BioEnergy Lists: Improved Biomass Cooking Stoves

From ronallarson at QWEST.NET Sun Jun 1 10:11:11 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:24 2004
Subject: Energy in V.S. out.....
In-Reply-To: <200305311603.h4VG35o04250@ns1.repp.org>
Message-ID: <SUN.1.JUN.2003.081111.0600.RONALLARSON@QWEST.NET>

Crispin and stovers

You said yesterday (with my interspersed notes):

>We should remember that when one talks of large socal arrays the Sahara is
>often mentioned as an ideal place for large scale implementation. The
>Sahara is, in many places, clouded with high dust for months and although
>there is bright sunshine, the sun itself can't be seen. It is not clear
>where to point an array and focusing systems are useless for a fair portion
>of the time.

Agreed. I wish I knew more about why the Sahara is so poor for insolation
and how much degradation there is now compared to 20 years ago, when it
seemed quite clear to me.
>
>The Western US deserts seem to be far clearer, true?

Yes. However our EPA is mandating our Western States to do more to clean
up what we call "regional haze" - which has gotten steadily worse over
time - due to particulates from coal plants. Many states (not my own of
Colorado) have endorsed a regional plan for cleanup. We as usual are going
it alone - which probably means nothing will be done. The regional (not
state) plan calls for a renewable portfolio standard that is more
comprehensive than any other I have seen (I think 20% RE energy by 2015?).
To get on the subject of biomass (not exactly stoves) - there is a role in
here for biomass - but most likely wind would be the big winner. However
many of the affected haze states have a better solar resource than wind
resource - so that ties in to this PV question.

>
>As for the energy content of a solar PV array, I suspect that the figures
>for 'energy content' don't reflect the gasoline the plant operator used to
>make the epoxy that glues the array together and so on. The "real" energy
>content of a panel would require that one simulate a whole city with
>education and retirement homes manufacturing only panels so one ca see what
>energy investment is made in a whole community in order to produce panels.
>I really doubt that the power generated by the panel will come close to the
>total energy portion expended by a society in creating the panel.
>
rwl: No - the payback time computations I believe cover all the things you
talk about. The biggest bump comes from the aluminum in the frame.
The most recent issue of "Science" (Issue 5623, p 1219) talks about
dye-sensitized TiO2 nanocrystal approach, a recent very positive result, and
a possible near-term cost reduction by a factor of five. My guess is that
this will have a big reduction in energy payback time.
As I am trying to track down why people think renewables can't be a net
energy producer, I'd like to understand where you hear otherwise. Wind has
a payback measured in months - why should PV at a few years be a surprise?
(I have heard this wind # may not include the concrete - so I need to check
further)

>A solar panel is really a battery that is activated by direct sunlight.

rwl: I don't like the analogy. I am comfortable that it is an energy
converter - photons generating electrons. Incidentally the above mentioned
approach operates differently - conduction of the electrons is not through
the same material where the electrons are produced. Only now at 10% or so -
but I think we will see higher. Swiss inventor's name is Gratzel.

>
>There are highly positive energy returns on hydro systems and
>probably solar
>steam engines which have a far higher % energy capture figure.

RWL: Yes. Hydro is not well-favored by many because of the land-use and
silting issues, but certainly once one has head, the efficiency of
conversion can be high - and I think (not sure) the same for energy payback
time. Run of the river hydro should certainly have good energy payback
time.
I was greatly surprised to read that hydrogen production (trying to get a
tie-in to future cooking needs in this digression) can be quite efficient
using solar concentrators - people believe they can do better than 60% with
high temperature reactions. Incidentally I think the PV record efficiency
is over 30% at 50 suns (not sure what scale that was at) - which is better
than most remote diesel uses - and you only have one shot at those photons.
>
>Regards
>Crispin in need of a little solar heat at this time of year myself

RWL: we just had a record (for May) day of 94 F (almost 39C) recently.
Your achieving comfort (heat) from solar sources is easier and cheaper than
ours (coolth) - but air-conditioning is driving our (very high marginal
cost) electricity demand on these hot days - right when solar (PV and STE,
not wind) is doing its best job. A few states are understanding this - but
not ours.

Ron
>

From ronallarson at QWEST.NET Sun Jun 1 10:26:11 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:24 2004
Subject: more on clay, potters, and charcoal-making stoves
Message-ID: <SUN.1.JUN.2003.082611.0600.RONALLARSON@QWEST.NET>

Stovers: Richard Boyt and I are having a (semi-private) discussion on
making charcoal-making stoves out of clay. Please ignore unless you think
you may want to try the same.

Richard has sent me a new paper design which has gone to Tom Miles, along
with some of my comments. My notes will be unintelligible until you see
Richard's nice sketch - so I am not sending them; this note is only on my
own progress - which Richard has been kind enough to continue on.

Richard:

The purpose of this post is mainly to describe the new ideas (#3 and 4) I
am trying out after the previously mentioned designs in my post of May 25 to
you and "Stoves". After this next week, this post will allow me to be more
concise on what I have learned from working with clay for natural-draft
charcoal-making stoves (which require separate and fairly complete control
of both primary and secondary air). The older versions (just out of kiln -
no testing yet)

#1 - double walled ceramic two "can" affair- each of height about 18.5 cm
and ID = 10.5 cm
and
"#2 - hourglass design" - single wall - total height of 37 cm, with smallest
"throat" of ID =7.5 cm

New are two of single wall design:
#3 is a thrown single tall cylinder of 24 cm total height and ID = 9.5 cm

#4 is a slab-built a little taller (29 cm) and narrower (8 cm)

Like #1, both of these are "welded" to flat bottom "disks (flat plates -
not washers)" of about 19-20 cm diameter to provide better stability.

Still trying for preheating, #3 has a vertical heat collecting "rectangular
channel (RC)" (with inner dimensions of about 5 x 20 mm) on the outer
portion of the upper combustion chamber" that should allow some preheating
of air. This can be bypassed. Then a full ring surrounds all the secondary
air inlet holes with dimensions about like the RC. This is supposed to
provide a wind shield and some secondary air heating. Maybe 50 small
secondary air holes of diameter maybe 2mm - these all punched with small
"drill". I have found it much easier to punch these through clay than
through metal.
At the bottom the primary air holes are maybe 8 mm across and maybe 15-20
of them. I created a wind shield for these bottom holes by using a thin
"slanted washer" that is also supposed to provide a total air seal and
structural support between the vertical wall and the bottom stability disk.
I found this somewhat difficult to do at first - but think a good potter
could do the whole thing in well less than an hour (the "slanted washer" in
5-10 minutes).

#4 (two initially 1/4" thick (6mm) tall flat slab pieces) is somewhat
similar - but here I tried to put the heat collecting vertical section
inside rather than outside. I created the (now) roughly triangular down
draft portion with one thinner "strip" that I "welded" in place (in #2, I
needed three separate pieces to create the air preheat "column"). I
continued the "inner welded strip" down through the fuel (pyrolyzing)
section the same way, but with these two air supply sections separated from
each other by a small barrier. The "diameter" of this sort of triangular
cross section "hollow column" is about 25 mm. There are upper and lower
outer holes for plugging or partial plugging for both the primary and
secondary air regions.

I welded small "handles" on all but #2 hourglass (had gotten too dry by
time I remembered). I fired first at cone 06 and later at cone 9 - after
adding a bit of glaze at places where cracks had appeared or I thought might
appear. The only bad cracks appeared in #1 (double wall slab) and I think
will be tough to avoid. The glaze did mostly a good job of filling these,
but I do have some leakage - but I don't think is in places which will much
influence performance. I am guessing form this experience that we may
decide that a double wall is too tough to implement in clay - and that the
outer "wall" can be made out of light gauge metal. Out of all the 5 pieces
making up these four stoves, I only ended up with one obvious small crack at
the bottom of one - and this was my fault for not being more careful in a
patch.

Observations from a "potting perspective" so far:
I think the overall primary and secondary air-control capability from
working with clay is very good. I believe I have gotten a reasonable
approximation to commercial construction techniques when working with these
pyrolyzing-type stoves. Whether it can stand up to regular use for very
long times remains to be seen. I am still not happy with what I have - but
the next week should allow me to learn a good bit more about the ease of use
of different types - as I now can check:
single (2,3,4) vs. double walls (#1),
shielded (1,3,4) vs. unshielded (#2),
stackable (#1) vs. unipiece (# 2,3,4);
secondary air pre-heat vs. not (most all cases),
ability to "hang" metal both inside and outside or none (for all cases, I
think).
broad conical base (#2) vs. large flat bottom plate

I am worried I may not:
a). have allowed for enough air flow (paths seemed to have shrunk more
than I thought - and I can't change them now)
b). have done a good enough job with the bottom grates, but think that
will be easy to fix in later models. The clay was still too wet when I was
working most of the grates into place. I need to do a better job on
measuring before barging ahead - as I could do with simpler geometries.

One of these four ought to work like the metal ones you and I have tested.

So this is to ask you for any further comments based on this again crude
description. I am sending separately comments on your nice sketch which Tom
Miles will figure out how to get up at his site.

Ron

From snkm at BTL.NET Sun Jun 1 10:44:23 2003
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:24 2004
Subject: Charcoal making
Message-ID: <SUN.1.JUN.2003.084423.0600.SNKM@BTL.NET>

Dear Listers --

As I have an ever increasing pile of coconut shells in regards to this
venture:

http://www.turneffecoconut.com

And am ever searching for how best to optimize my need of heat and by
products -- in this case charcoal??

That is -- can't I eat my cake and still have it to??

Well -- here is one good looking solution:

http://aewgasifiers.netfirms.com/charcoalmaker.htm

That might be of interest to some on this list.

The blurb:

The present methods used for charcoal making from Coconut Shells is energy
inefficient and also detrimental to Environment. By adopting old
techniques, lots of smoke is left to the atmosphere causing pollution. The
heat emitted from the volatiles present in the Coconut Shells is also wasted.

Whereas in Thermal Gasifiers, the coconut Shells are burnt under controlled
conditions with limited amount of air and by Thermo-Chemical reaction, the
volatiles also are converted into gaseous fuel. By continuously creating
movement in the combustion zone, the charcoal formed is discharged through
a rotating grate. The gas formed will be fed to a specially made Burner
where it can be burnt for emitting heat. The Burner can located at the user
point for any heating needs. Hence in this method, Charcoal is the main
product and the gas is bye-product. This method can be adopted at the
Biomass Source point so that transport charges can be saved. Any
non-technical persons can operate this Gasifier and also the system needs
only 1.5 HP Power to operate it. This is a Environmental Friendly Device.

******************

Then there is this:

Charcoal output 150 Kg/Hr ( 3 Tons/Day approx.)

Feed Material Coconut Shell Pieces

Feed Consumption 500 Kgs/Hour

Oops -- a little to big for my operation --

Peter Singfield - Belize

From lanny at ROMAN.NET Sun Jun 1 10:42:35 2003
From: lanny at ROMAN.NET (Lanny Henson)
Date: Tue Aug 10 18:30:24 2004
Subject: A Bulky Biomass Burner (BBBD1)
Message-ID: <SUN.1.JUN.2003.104235.0400.LANNY@ROMAN.NET>

Dear Stove Friends,
I did a quick project to lift my spirits. Been very busy, cant wait till I
can get a whole weekend for hobby time.

I thought that a burner to burn bulky biomass may be handy. I welded 3 drums
together and added a door and a central chimney system sort of like a
sawdust stove.
It works great, by that I mean that it burns clear. It burns newspaper,
magazines, junk mail, leaves, grass, limbs and scrap wood and with sawdust
mixed in.
It has a few problems. The door leaks smoke and is too small. Also it is top
heavy. I leaned a short ladder ageist it and it fell over, while burning!
But I am very pleased since it is a first prototype.
I may try to morph this thing into a charcoal unit.
Lanny Henson

 

http://www.lanny.us/bbbd1.html

From ronallarson at QWEST.NET Sun Jun 1 11:31:47 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:24 2004
Subject: A Bulky Biomass Burner (BBBD1)
In-Reply-To: <200306011421.h51ELpo24781@ns1.repp.org>
Message-ID: <SUN.1.JUN.2003.093147.0600.RONALLARSON@QWEST.NET>

Lanny - I like the idea of turning it into a charcoal- maker. Hope you can
also find a way to generate steam or something useful as well.

Re the door - should be able to get an interior low pressure if the door is
below the majority of the flames.

Picture soon?

Ron

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of Lanny Henson
>Sent: Sunday, June 01, 2003 8:43 AM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: A Bulky Biomass Burner (BBBD1)
>
>
>---------------------- Information from the mail header
>-----------------------
>Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
>Poster: Lanny Henson <lanny@ROMAN.NET>
>Subject: A Bulky Biomass Burner (BBBD1)
>-------------------------------------------------------------------
>------------
>
>Dear Stove Friends,
>I did a quick project to lift my spirits. Been very busy, cant wait till I
>can get a whole weekend for hobby time.
>
>I thought that a burner to burn bulky biomass may be handy. I
>welded 3 drums
>together and added a door and a central chimney system sort of like a
>sawdust stove.
>It works great, by that I mean that it burns clear. It burns newspaper,
>magazines, junk mail, leaves, grass, limbs and scrap wood and with sawdust
>mixed in.
>It has a few problems. The door leaks smoke and is too small. Also
>it is top
>heavy. I leaned a short ladder ageist it and it fell over, while burning!
>But I am very pleased since it is a first prototype.
>I may try to morph this thing into a charcoal unit.
>Lanny Henson
>
>
>
>http://www.lanny.us/bbbd1.html
>
>

From ronallarson at QWEST.NET Sun Jun 1 11:49:22 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:24 2004
Subject: Charcoal making
In-Reply-To: <200306011403.h51E39o24579@ns1.repp.org>
Message-ID: <SUN.1.JUN.2003.094922.0600.RONALLARSON@QWEST.NET>

Peter (cc stoves)

Today you said (and I add a few comments):

>Dear Listers --
>
>As I have an ever increasing pile of coconut shells in regards to this
>venture:
>
>http://www.turneffecoconut.com

RWL: Yours is a very effective web site. I enjoyed reading through it.
Looks like you must be a pretty important part of that local economy.
>
>And am ever searching for how best to optimize my need of heat and by
>products -- in this case charcoal??
>
>That is -- can't I eat my cake and still have it to??

RWL: I hope so - but we still don't seem to have all the right
ingredients. That is I wish we had a low cost external combustion unit - or
efficient low cost thermoelectrics, etc. It's coming. We just need higher
petrol and gas prices.
>
>Well -- here is one good looking solution:
>
>http://aewgasifiers.netfirms.com/charcoalmaker.htm

RWL: I liked the idea that the waste gas was considered the "by-product".
I don't think enough people developing gasifiers think of the charcoal as
having enough value. But as you know the usual production of charcoal is
awfully wasteful and polluting. Has to be a way to combine the processes
effectively.
This Indian firm looks good - but others on the list may know also of
others there doing the same or similar. India seems to be in the lead in
this area.
I like the idea that they have some sort of rotating platform.
Note the message today also from Lanny Henson - somewhat similar.

best of luck. Ron

>
>That might be of interest to some on this list.
>
>The blurb:
>
>The present methods used for charcoal making from Coconut Shells is energy
>inefficient and also detrimental to Environment. By adopting old
>techniques, lots of smoke is left to the atmosphere causing pollution. The
>heat emitted from the volatiles present in the Coconut Shells is
>also wasted.
>
>Whereas in Thermal Gasifiers, the coconut Shells are burnt under controlled
>conditions with limited amount of air and by Thermo-Chemical reaction, the
>volatiles also are converted into gaseous fuel. By continuously creating
>movement in the combustion zone, the charcoal formed is discharged through
>a rotating grate. The gas formed will be fed to a specially made Burner
>where it can be burnt for emitting heat. The Burner can located at the user
>point for any heating needs. Hence in this method, Charcoal is the main
>product and the gas is bye-product. This method can be adopted at the
>Biomass Source point so that transport charges can be saved. Any
>non-technical persons can operate this Gasifier and also the system needs
>only 1.5 HP Power to operate it. This is a Environmental Friendly Device.
>
>******************
>
>Then there is this:
>
>Charcoal output 150 Kg/Hr ( 3 Tons/Day approx.)
>
>Feed Material Coconut Shell Pieces
>
>Feed Consumption 500 Kgs/Hour
>
>
>Oops -- a little to big for my operation --
>
>Peter Singfield - Belize
>
>

From snkm at BTL.NET Sun Jun 1 13:03:58 2003
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:24 2004
Subject: Charcoal making
Message-ID: <SUN.1.JUN.2003.110358.0600.SNKM@BTL.NET>

Getting to the meat:

> RWL: I hope so - but we still don't seem to have all the right
>ingredients. That is I wish we had a low cost external combustion unit - or
>efficient low cost thermoelectrics, etc. It's coming. We just need higher
>petrol and gas prices.

All to true -- fossil fuels are still to cheap.

But I have always been under the impression that it is much easier to
gasify charcoal to run an IC engine than it is to gasify biomass.

In regards to:

>or efficient low cost thermoelectric

That situation has improved dramatically just lately. Here are just to
examples:

http://stonepathpower.com/product_info.htm

We suspect but can't prove that they are accomplishing this feat using the
ORC (Organic Rankine Cycle) -- that is a refrigerant as a working fluid.

Next:

http://www.users.globalnet.co.uk/~mbiddle/

This system is a proclaimed ORC and has as Working fluid - Hydrofluoroether

More on that at:

http://st-support-cooling-electronics.web.cern.ch/st-support-cooling-electro
nics/CWGWeb/TABLE8-5.PDF

As for me here -- I do have one spare -- single cylinder -- old Style
lister diesel -- 6 HP -- 650 RPM -- that is just dying to be converted into
a 6 hp steam or ORC engine.

Cost of that -- new -- delivered here to my house in Belize -- was $650 US.

Meanwhile I increase my reserves of fossil fuel -- namely used car engine
oil. Which I pay 50 cents US per gallon for.

That might be expensive in the US -- but here where diesel sells for $250
per US gallon -- it is a bargain.

After my cisterns are filled -- and they have settled for a few years -- to
clear oil again -- this "fuel" will work fine in my other old style Listers
-- and solves where to get the lubrication in a Mad Max world -- problems.

We probably have 5 more years of cheap fossil fuels -- and that is not so
much time to get "ready".

Get ready for Mad Max world to!!

Peter

At 09:49 AM 6/1/2003 -0600, you wrote:
>Peter (cc stoves)
>
> Today you said (and I add a few comments):
>
>
>>Dear Listers --
>>
>>As I have an ever increasing pile of coconut shells in regards to this
>>venture:
>>
>>http://www.turneffecoconut.com
>
> RWL: Yours is a very effective web site. I enjoyed reading through it.
>Looks like you must be a pretty important part of that local economy.
>>
>>And am ever searching for how best to optimize my need of heat and by
>>products -- in this case charcoal??
>>
>>That is -- can't I eat my cake and still have it to??
>
> RWL: I hope so - but we still don't seem to have all the right
>ingredients. That is I wish we had a low cost external combustion unit - or
>efficient low cost thermoelectrics, etc. It's coming. We just need higher
>petrol and gas prices.
>>
>>Well -- here is one good looking solution:
>>
>>http://aewgasifiers.netfirms.com/charcoalmaker.htm
>
> RWL: I liked the idea that the waste gas was considered the "by-product".
>I don't think enough people developing gasifiers think of the charcoal as
>having enough value. But as you know the usual production of charcoal is
>awfully wasteful and polluting. Has to be a way to combine the processes
>effectively.
> This Indian firm looks good - but others on the list may know also of
>others there doing the same or similar. India seems to be in the lead in
>this area.
> I like the idea that they have some sort of rotating platform.
> Note the message today also from Lanny Henson - somewhat similar.
>
>best of luck. Ron
>
>>
>>That might be of interest to some on this list.
>>
>>The blurb:
>>
>>The present methods used for charcoal making from Coconut Shells is energy
>>inefficient and also detrimental to Environment. By adopting old
>>techniques, lots of smoke is left to the atmosphere causing pollution. The
>>heat emitted from the volatiles present in the Coconut Shells is
>>also wasted.
>>
>>Whereas in Thermal Gasifiers, the coconut Shells are burnt under controlled
>>conditions with limited amount of air and by Thermo-Chemical reaction, the
>>volatiles also are converted into gaseous fuel. By continuously creating
>>movement in the combustion zone, the charcoal formed is discharged through
>>a rotating grate. The gas formed will be fed to a specially made Burner
>>where it can be burnt for emitting heat. The Burner can located at the user
>>point for any heating needs. Hence in this method, Charcoal is the main
>>product and the gas is bye-product. This method can be adopted at the
>>Biomass Source point so that transport charges can be saved. Any
>>non-technical persons can operate this Gasifier and also the system needs
>>only 1.5 HP Power to operate it. This is a Environmental Friendly Device.
>>
>>******************
>>
>>Then there is this:
>>
>>Charcoal output 150 Kg/Hr ( 3 Tons/Day approx.)
>>
>>Feed Material Coconut Shell Pieces
>>
>>Feed Consumption 500 Kgs/Hour
>>
>>
>>Oops -- a little to big for my operation --
>>
>>Peter Singfield - Belize
>>
>>
>
>

From hseaver at CYBERSHAMANIX.COM Sun Jun 1 13:48:32 2003
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:30:24 2004
Subject: Charcoal making
In-Reply-To: <3.0.32.20030601110210.00954c20@btlmail.btl.net>
Message-ID: <SUN.1.JUN.2003.124832.0500.HSEAVER@CYBERSHAMANIX.COM>

On Sun, Jun 01, 2003 at 11:03:58AM -0600, Peter Singfield wrote:
>
> >or efficient low cost thermoelectric
>
> That situation has improved dramatically just lately. Here are just to
> examples:
>
> http://stonepathpower.com/product_info.htm
>
> We suspect but can't prove that they are accomplishing this feat using the
> ORC (Organic Rankine Cycle) -- that is a refrigerant as a working fluid.
>
> Next:
>
> http://www.users.globalnet.co.uk/~mbiddle/
>
> This system is a proclaimed ORC and has as Working fluid - Hydrofluoroether
>

Those aren't thermoelectric.
Here are examples of thermoelectric:

http://www.hi-z.com/websit07.htm

http://www.tetech.com/modules/

http://www.peltier-info.com/generators.html

 

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com

From adkarve at PN2.VSNL.NET.IN Sun Jun 1 11:33:34 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:24 2004
Subject: A Bulky Biomass Burner (BBBD1)
Message-ID: <SUN.1.JUN.2003.210334.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Mr. Henson,
A contraption very similar to what you describe (but more stable) was made
by us to burn dry leaves in the campus of a school. The burner was a
metallic cylinder having a diameter of about 2 feet (60 cm) and height of
about 3 feet 9cm. It had a central column, having a diameter of 6 inches (15
cm). After packing the leaves tightly in the stove, this column was removed
to leave a central lumen. This stove burned continuously for almost 3 hours,
with a beautiful blue flame. They used this stove in the school hostel for
cooking food. However, the biomass was completely burned to give ash and not
charcoal.
Yours
A.D.Karve
-----Original Message-----
From: Lanny Henson <lanny@ROMAN.NET>
To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
Date: Sunday, June 01, 2003 8:37 PM
Subject: [STOVES] A Bulky Biomass Burner (BBBD1)

>Dear Stove Friends,
>I did a quick project to lift my spirits. Been very busy, cant wait till I
>can get a whole weekend for hobby time.
>
>I thought that a burner to burn bulky biomass may be handy. I welded 3
drums
>together and added a door and a central chimney system sort of like a
>sawdust stove.
>It works great, by that I mean that it burns clear. It burns newspaper,
>magazines, junk mail, leaves, grass, limbs and scrap wood and with sawdust
>mixed in.
>It has a few problems. The door leaks smoke and is too small. Also it is
top
>heavy. I leaned a short ladder ageist it and it fell over, while burning!
>But I am very pleased since it is a first prototype.
>I may try to morph this thing into a charcoal unit.
>Lanny Henson
>
>
>
>http://www.lanny.us/bbbd1.html
>

From adkarve at PN2.VSNL.NET.IN Mon Jun 2 22:22:14 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:24 2004
Subject: stove for light biomass
Message-ID: <TUE.3.JUN.2003.075214.0530.ADKARVE@PN2.VSNL.NET.IN>

Tom Reed wated to know structural details of the stove described by me in my
last communication. The stove consists of a cylindrical metallic body,
closed at the bottom, but having a close fitting lid at the top. The lid
has the same diameter as the cylinder. The lid has also a hole in the
centre, having the same diameter as the central column that is kept in the
stove while packing the fuel into it. The stove body, i.e. the metallic
cylinder also has a hole at the bottom, having the same diameter as the
central column. Before packing the light biomass into the stove, a wooden
pole or any other cylindrical long object is inserted into the hole at the
bottom of the stove and another similar object is held vertically in the
centre of the stove body. These two pieces together form an L. Light
biomass like sawdust, wood shavings, dry leaves, paper cuttings, rags, etc.
can be used as fuel. These items are packed around the central column.
After filling the stove with the fuel, one puts the lid on. The central
column juts out through the hold in the lid. The column as well as the
horizontal piece at the bottom are both gently removed, to leave an L shaped
lumen in the biomass. The biomass is ignited from the bottom, by inserting
a burning tinder through the horizontal arm of the L. The flame comes out of
the hole in the lid. The lid is also fitted with three supports on which the
cookpot rests. For getting a blue flame, there is a definite
length-to-breadth ratio of the central lumen left in the biomass. The lumen
height has to be 6 times as much as the lumen diameter. Thus in the case of
our oil-drum stove, because the height of the central lumen was 90 cm, the
diameter had to be 15 cm. If the height is less, one has to have a
correspondingly narrower lumen. We have now made a smaller stove, that is
just 15 cm tall. In this case the diameter of the lumen was only 2.5 cm.
The flame coming out of such a stove was too small. Therefore, we provided
this stove with four vertical holes, each 2.5 cm wide. It accommodates about
1 kg sawdust and burns continuously with a blue flame for about 45 minutes.
In this particular case, the pot supports had to be 4 cm tall to get the
maximum efficiency. The height of the supports has to be determined by trial
and error.
Dr.A.D.Karve, President,
Appropriate Rural Technology Institute,

From jeff.forssell at CFL.SE Tue Jun 3 02:40:12 2003
From: jeff.forssell at CFL.SE (Jeff Forssell)
Date: Tue Aug 10 18:30:24 2004
Subject: stove for light biomass
Message-ID: <TUE.3.JUN.2003.084012.0200.JEFF.FORSSELL@CFL.SE>

I have a hard time visulizing this:
> We have now made a smaller
> stove, that is
> just 15 cm tall. In this case the diameter of the lumen was
> only 2.5 cm.
> The flame coming out of such a stove was too small.
> Therefore, we provided
> this stove with four vertical holes, each 2.5 cm wide. It
> accommodates about
> 1 kg sawdust and burns continuously with a blue flame for
> about 45 minutes.
>
Do you have a link to some pictures/drawings

Jeff Forssell (tv? s)
SWEDISH AGENCY FOR FLEXIBLE LEARNING (CFL)
Box 3024
SE-871 03 H?RN?SAND /Sweden

<http://www.cfl.se/english/index.htm>
+46(0)611-55 79 48 (Work) +46(0)611-55 79 80 (Fax Work)
+46(0)611-22 1 44 (Home) ( mobil: 070- 35 80 306; [070-4091514])

residence:
Gamla Karlebyv?gen 14 / SE-871 33 H?rn?sand /Sweden

e-mail: every workday: jeff.forssell@cfl.se <mailto:jeff.forssell@cfl.se>
(travel, visiting: jeff_forssell@hotmail.com & MSMessenger)

Personal homepage: <http://www.torget.se/users/i/iluhya/index.htm>
My village technology page: http://home.bip.net/jeff.forssell

Instant messengers Odigo 792701 (ICQ: 55800587; NM/MSM use hotmail address)

From rdboyt at YAHOO.COM Wed Jun 4 08:11:15 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:24 2004
Subject: Ceramics for Stoves, Part 3B
Message-ID: <WED.4.JUN.2003.051115.0700.RDBOYT@YAHOO.COM>

Ceramics for Stoves, Part 3B
Test Firing Local Clays- Re-discovery of a "Natural"
Kiln

Again, greetings from Pottershop Holler, where the sky
gets smaller as the trees grow taller.

Before I continue with ideas on primitive kiln and
stove designs, I want to backtrack to fill a few holes
I've left in earlier writings. Sometimes I have
called for equipment or materials that are not likely
to be available to a primitive stove maker. If a pick
ax is not available for digging clay, you could use a
sharp forked stick. To remove excess water from the
clay slurry, you could use sheets of newspaper,
cardboard, plastic, metal, tin cans, plates, tightly
woven cloth, buckets, tubs, flat rocks, broad leaves,
animal skins, wooden boards and bowls-- anything that
can hold the slurry and absorb and/or evaporate excess
water can substitute for the plaster-of-paris bats and
bowls I previously called for. After we build a fair
sized kiln, we can make all the bats, bowls, and tubs
we'll ever need.

I suggested that very early kilns may have been
specially shaped bon-fires, and I suggest that Mother
Nature herself may have shown one way to build them.
Lightning sets fire to the forest and finds the hollow
center of a tree. The tree then becomes the stove,
the fuel, and the chimney. This combination creates a
reverberatory furnace with the heat bouncing back and
forth between the glowing red hot walls. Very hot,
and a roaring torch of flame out the top. On a
related note, I just heard over the BBC that in
Tasmania, the world's tallest tree "El Grande", some
74 meters (242') high and nearly 400 years old has
burned after accidentally catching fire while workers
were clearing brush. I'll make an uninformed guess
that it was hollow with openings at its base and along
the trunk where limbs had been discarded. It would be
very difficult to stop a fire like this, once started.

A few years ago, we harvested some big old declining
oaks and found a few that were hollow and useful only
for firewood. We cut one to firewood lengths and
propped a half-meter (18") chunk on end on several
rocks to make space at the bottom for a draft, and
built a fire inside. It smoked and flamed a bit at
first, but once it got going, the entire interior
glowed, but with no sound, no flame, no smoke. Just a
pale transparent violet haze dancing over the surface
of the red-hot coals and an invisible steady hot
column of gasses coming out the top. We lit a few of
these "stump stoves" for family gatherings, and with a
grill on top, cooked hamburgers; and with sharp
pointed sticks, cooked hot dogs. The heat was so
controlled that I found I could roast marshmallows
with my fingers without burning fingers or
marshmallows. More convenient, however with a short
throwaway plastic fork that stays cool so the
marshmallows don't slide off. Try that over a
bon-fire.

A chimney made of a stack of tin cans can give the
fire quite a "kick". Remove the ends of several cans.
Crimp one end of each can with the jaws of a modified
pair of pliers. Insert the crimped end of each can
into the uncrimped end of another until you have the
height you want. Make an adapter out of a larger can
or metal pail to bridge the opening at the top of the
stump. Light weight, easy on, easy off (more details
on how to make tin can chimneys later).

So it is growing dark and the party is over, and it is
time to break camp. No need for flashlights-- just
drop in a couple of sticks. They burst into flame
almost instantly, and a half meter (18") plume of
bright yellow flame races upward, lighting the
landscape. Now, time to put the fire out. Two of us
lift the still burning, yet heavy stump stove off its
supports and place it firmly on soft ground to cut off
all combustion air. Amazingly, it has been burning
steadily for two hours, and the outside isn't even
warm. This leads me to conjecture that wood doesn't
burn (Das, you'll like this!). When hot enough, wood
pyrolizes, giving off combustible gasses. It is these
gasses that burn and in burning heat the wood to cause
it to give off more gasses which burn. I suggest that
this is the much same effect as seen in boiling water.
Adding heat does not raise the temperature of the
water, it only makes it boil more quickly. The
boiling off or evaporation of water vapor literally
keeps the water from getting hotter. Same with wood.
Starting off at about 250 degrees C (500 degrees F),
the boiling off of gasses keeps the wood from getting
hotter. Once completely pyrolized, the wood becomes
char, but char does not burn. Like wood, it vaporizes
and the gasses burn to heat the char to drive off more
gasses. I'd bet this is a considerable
oversimplification, but observation suggests that this
may be at least partly true.

Time to leave. Slosh the glowing insides with water--
a toy water gun works for stubborn hot spots. Cap the
top with a hunk of well-weighted sheet metal sealed by
a gasket of wet wood ash. Charcoal can really be
stubborn in not going out. If it can, it will find
even the smallest leak of air. However, we used one
single stump stove for three parties before it finally
burned out one side and collapsed. Save any char that
is left. We can use it later to make a lightweight
ceramic insulation. Also save ash. We can use it to
make a high-potassium liquid that serves as a
semi-glaze. I have used it to harden the surface of
lightweight ceramic insulation. More on that later.

If hollow stumps are in short supply, split a big
solid chunk of wood, hew out the center, and bind the
outer pieces back together with bailing wire, big
rubber bands cut from old inner tubes, or anything
else that will hold the wood pieces tightly together.
Use wet wood ash or clay slurry to make airtight
gaskets where needed, or to plug open knot holes or
beef up thin places. To get a really hot burn, stack
the stumps. High enough, and it ought to roar!

This whole idea of a stump stove is so simple that I
think it likely that prehistoric people used it to
fire their pots. Careful examination of chunks of
unburned char can show how it was burned. The
curvature of growth rings and the character of the
burned surfaces suggest fire inside a cavity.
However, the few archeologists I have talked to
admitted that they had not heard of the idea of very
early stump stoves.

I admit, I cut my stump stoves to length with a chain
saw. Not much chance of that in a primitive
environment, but cross-cut saws and axes are not
uncommon in underdeveloped countries. A chain saw
could cut vertical slots deep into the log to prepare
a hole. A long drill bit could make a pilot hole, and
careful firing might widen it enough to make a stump
stove. Perhaps the greatest value of a stump stove is
its demonstration of the principle of reverberatory
geometry that can be used to create efficient cooking
stoves as well as kilns.

So we have a small, very primitive kin capable of
firing clay. Many other kiln designs could do the
job, but most of them involve heavy, stationary
structures and lots of work, materials, and techniques
not available to very primitive stove makers. I
encourage readers to explore and report on other
designs for simple kilns. I confess that I'm still
getting a lot of use out of my tabletop electric kiln.

Next entry should be Ceramics for Stoves: 3C- "Test
Firing Local Clays Using a Primitive Kiln".

In the mean time, prepare several disks of plastic
clay about 1 cm (1/2") thick and 3 cm (1.75") in
diameter. Weigh each one accurately, then dry and
weigh again to determine the percentage weight of
water required to reach plasticity.

Sorry this goes slow, but I'm still figuring out how
to make it all work. Be patient. I think I know
where I'm going. By the way, use a mirror when you
look down the inside a hot tin can chimney, and oh
yes, don't worry-- you eyebrows will grow back.

Dick Boyt
20479 Panda Rd
Neosho, MO 64850
U.S.A.
rdboyt@yahoo.com

__________________________________
Do you Yahoo!?
Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
http://calendar.yahoo.com

From psanders at ILSTU.EDU Thu Jun 5 18:26:39 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:24 2004
Subject: Where to find this reference
Message-ID: <THU.5.JUN.2003.172639.0500.PSANDERS@ILSTU.EDU>

Stovers,

I cannot locate my copy nor reference to the publication that said that
indoor air pollution is the #4 worst cause of early death in developing
countries. I thought it was by the WHO, but I cannot find the publication
on the web.

Please send the title and where I can download or read a copy.

Thanks,

Paul
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From robertoescardo at ARNET.COM.AR Thu Jun 5 20:03:53 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:24 2004
Subject: Where to find this reference
Message-ID: <THU.5.JUN.2003.210353.0300.ROBERTOESCARDO@ARNET.COM.AR>

Dear Paul:
The report can be found at
http://www.who.int/whr/2002/en/
The important parts are chapter four and annex 6 and 14_16
Regards
Roberto

----- Original Message -----
From: "Paul S. Anderson" <psanders@ILSTU.EDU>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, June 05, 2003 7:26 PM
Subject: [STOVES] Where to find this reference

> Stovers,
>
> I cannot locate my copy nor reference to the publication that said that
> indoor air pollution is the #4 worst cause of early death in developing
> countries. I thought it was by the WHO, but I cannot find the publication
> on the web.
>
> Please send the title and where I can download or read a copy.
>
> Thanks,
>
> Paul
> Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From robertoescardo at ARNET.COM.AR Fri Jun 6 15:06:11 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:24 2004
Subject: Polyethylene and PVC separation
Message-ID: <FRI.6.JUN.2003.160611.0300.ROBERTOESCARDO@ARNET.COM.AR>

Does anybody know about a cheap and simple method to separate PVC from polyethylene? We tested paper - poliethilene - sawdust briquettes and thet burn very well, but PVC contamination is a danger. Thanks
Roberto.

From tmiles at TRMILES.COM Sun Jun 8 01:13:11 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:24 2004
Subject: more on clay, potters, and charcoal-making stoves
Message-ID: <SUN.8.JUN.2003.011311.0400.TMILES@TRMILES.COM>

The ceramic charcoal making stove that Ron Larson and Richard Boyt are
discussing can be seen at:
http://www.repp.org/discussiongroups/resources/stoves/Boyt/ceramstove/ceram
stove.html

or from the main stoves page find Ron Larson or Richard Boyt at:
http://www.repp.org/discussiongroups/resources/stoves/

Tom Miles

From tmiles at TRMILES.COM Sun Jun 8 16:20:07 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:24 2004
Subject: Biomass Cookstoves Weblog 6/8/2003
Message-ID: <SUN.8.JUN.2003.132007.0700.TMILES@TRMILES.COM>

Ceramic stoves, insulation, charcoal and gasification are all reflected in
new additions to the Biomass Cookstoves website.

Richard Boyt continues his advice on ceramics for stoves with Testing Firing
Clays parts 3A - Primitive Kilns and 3B Rediscovery of a Natural Kiln. See
also How to Construct a Kiln for Clay Stove Firing by Christa Roth (ISFP
Malawi)

Richard Boyt and Ron Larson are discussing construction of a ceramic
charcoal making stove.

Richard Njagu shows us new pictures of his Henya Stove and the local clays
he uses.

http://www.repp.org/discussiongroups/resources/stoves/

Tom Miles

From ronallarson at QWEST.NET Sun Jun 8 19:57:51 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: Brief Report on Approvecho Meeting
Message-ID: <SUN.8.JUN.2003.175751.0600.RONALLARSON@QWEST.NET>

Stovers (cc Dean, attendees, Ethos):

I've now been back a few days from the small stoves testing meeting held at
the Approvecho facility near Cottage Grove Oregon (near Eugene). Dean is
writing up a full report (and I promised to add to it) and so I am just
going to throw in a few overall remarks that might help Dean (and I hope
others of us there will also write on their thoughts). And that
non-attendees will ask questions.

1. There were about 12-15 there - about half stove "veterans" and about
half newcomers - a good mix - all very interested in stoves.

2. A majority there were most interested in and knowledgeable on the
Rocket Stove. I was able to try some new tests with a charcoal-maker.
Others helped to run tests on four other donated stoves - those from Tom
Reed, Paul Anderson, Crispin, and Lanny Henson.

3. Two tests were run (and I assume Dean will give some reports later)
a) efficiency - a standard water load (5 liters) and a standard fuel supply
(if appropriate) - 700 grams wood.
b) emissions - a CO test with 4 liters water and 400 grams wood Two HOBO
CO meters at different heights in a fairly tight room (exchange time about
20 minutes. Also an older "smoke stack" unit (Enerec?) had been donated and
was only partly useful - but gave CO2 and O2 as well as CO readings when
higher than 0.1 % (not sufficiently sensitive for this meeting).

4. Most everyone alternately participated in the tests or in
lectures/classes in the AM or PM. One day with Larry Winiarski on design
principles (I missed this as I had quite a few stoves to test) ; another
day with Ken Goyer on insulative bricks. Other days were more flexible -
people mostly doing what they wanted. I had an hour or so to talk about
charcoal making. Tammy had to leave after end of day 2

5. Some new ideas for me to follow up on:

a) The placement of sawdust in a small can placed in the middle of the
combustion area seemed to have pyrolyzed successfully with the pyrolysis
gases helping out. I think doing this with sawdust (or leaves, etc) on the
outside might be better - insulating as well as adding to the fuel supply
and charcoal output. The radially directed heat can thereby be useful. The
outer fuel supply option has not yet tested.

b) Use of a thin metal horizontal "windpumper" deflector "disk" between
the pyrolysis and combustion regions to achieve a swirl (idea coming from
Jess and Morgan of Colorado State) - looked quite good. Seems like it could
have general applicability.

c) The balancing of a larger upper pyrolysis unit (coffee can) on the
lower fuel chamber (also coffee can - but smaller diameter) worked well.
Three screws could be on either the upper (pointed in) or lower can (pointed
out). I think the former would be better (easier to load fuel) - but I only
tried the latter. I had about (wasn't measured) a 7 mm gap between the
cans - and believe it was much too large - based on measured low CO2 (3%),
high O2(18%) readings obtained by Jess. In a test about 6-7 years ago they
were about equal at 10-11 % - which I think is a good range. Earlier, the
secondary air gap was much smaller (maybe 1-2 mm?), when the two cans were
of the same diameter (and wired together) or the whole was of one piece of
metal - with many small holes of 2-3 mm diameter. The Rocket had even
smaller(larger) levels of CO2(O2) - which also indicated low temperatures at
the pot due to excess air.
I now feel it important to control secondary air - for this excess air
reason.

d) Dean said he had some success in obtaining light output from slits in a
metal combustion region. I am anxious to try the same - I am going to try a
glass lantern "bowl" for the combustion region with a piece of 4" stove pipe
for the fuel container (and possibly some additional heat capture - but with
light and heat as the major purpose).

e) I was very impressed with the many types of insulative bricks that have
been developed. For me, one of the easiest to work with is a brick that
starts as 85% charcoal and 15% clay (final density about 50%). But also
saw some nice bricks made from vermiculite and pumice.

f) It is very important that the operator be able to see the flames. I
did a poor job at Approvecho (and is a problem with ceramics).

g) I need to work out a means of supporting the pot independently of the
pyrolysis and combustion chambers (for safety reasons)

h) In a separate message, I will report on the various ceramic designs
(none of which were too successful).

i) I need to become more familiar with the modeling program and results
given by Dale Andreatta -
http://www.repp.org/discussiongroups/resources/stoves/#Dale_Andreatta . His
analytical material needs to be expanded by others (Dale will be saying more
about the test room, I believe).

 

6. My main conclusions on this meeting and this sort of meeting:

a). A major benefit is being able to talk over ideas with other
researchers - both formally and informally. I hope Dean will plan another
and that others will jump in as well.

b). It is very helpful to have a standardized format of testing - even if
not perfect, and this type of meeting and testing should be replicated.

c). We still need to work out appropriate test procedures (such as
monitoring CO2).
1) Results should not be reported (or should be carefully caveated) if
the same amount of fuel cannot be consumed in the tests - or if the pots and
stoves are not relatively well matched. Not all stoves are designed for the
same jobs.
2) Foundations and government sources should support stove testing
laboratories in much larger numbers.
3) We should start a new "stoves" thread on test procedures.
4) I pointed out my unhappiness with the way efficiency computations
handled charcoal production (too complicated to explain here).

d). There is a lot to be gained from working closely with Universities on
class and special projects.

From ronallarson at QWEST.NET Sun Jun 8 21:01:47 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: Cookstoves as an student design project?
In-Reply-To: <001901c32be7$f63df080$1341083e@dell>
Message-ID: <SUN.8.JUN.2003.190147.0600.RONALLARSON@QWEST.NET>

Steven and Elsen:

1. First thanks to Elsen for replying while I was at the Approvecho
meeting.

2. Because I just sent out a general report on a meeting that partly
addresses exactly what you are asking about (student involvement) - and
because I want to get all "stove" list members thinking this way, I am going
public with a message you started in private. I think you will not mind -
but I apologize if needed.

3. More notes below - first on Elsen's response and then on your
questions.

>-----Original Message-----
>From: elk [mailto:elk@wananchi.com]
>Sent: Thursday, June 05, 2003 10:56 PM
>To: Dr. Steven Rogak; ronallarson@qwest.net
>Subject: Re: Cookstoves as an student design project?
>
>
>Stephen;
>
>Getting the right stove to the appropriate user and communicating the
>information while imparting the motivation to ensure said user
>actually uses
>stove in question........ there's a challenge equal to that of the stove
>design.

(RWL): Agreed. There are not many major success stories to report. The
country that has done the best job is China - and a report will be coming
soon on reasons why. We need to lower costs AND explain the many reasons
for spending a bit more for a better (more efficient, more healthy, etc)

>
>Institutional stoves may be easier though. The user possesses a somewhat
>different set of assessment criteria and a less subjective administrative
>judgment of the stove is normally made in addition to the actual
>users- e.g.
>manager + cook.

(RWL): Agreed. So your students might work in that direction. One way to
proceed might be to find successful stoves being used commercially and try
to figure out how to improve - or just to understand how the success was
achieved.
>
>To this end there's orphanages, refugee centres, schools, clinics and
>hospitals as well as restaurants and hotels...... and when there's a
>commercial aspect involved, objectivity is often increased.

(RWL): Agreed
>
>Might follow this thread via a church to one of their developing world
>'feeding centres & the like.
>
>BTW- any ideas where I could source very small TEGs (Thermo-electric
>generators)? I've a budding idea about slapping one of these on the side of
>a domestic charcoal 'jiko' here & generating a watt or so to power a small
>LED cluster hanging over the cook-pot........ might be an idea for one of
>your students to investigate. Now THAT wouldn't be a hard sell here! I'd be
>happy to get involved. I've the .8 watt white 9-LED clusters already.

(RWL): An interesting area for student work - not much has gone on here.
>
>Ronal- there's been some discussion about Russian-made TEGs on the
>list- did anyone ever mention sources?

(RWL): I have a friend doing work here - and can get him involved if
needed when anyone is going big. otherwise - look at
http://www.peltier-info.com/
>
>Be happy to discuss further. If the cost can be kept 'way down, I could get
>funding for production & dissemination on a commercial basis easily enough.
>A very big need for lighting here & it'd be a neat tie-in to our
>(Chardust's) eco-friendly charcoal manufacture.

(RWL): See also my notes sent out earlier today - which mention work by
Dean Still on this lighting issue.
>
>rgds;
>elk
>
>--------------------------
>Elsen L. Karstad
>elk@wananchi.com
>www.chardust.com
>Nairobi Kenya
>
>
>
>----- Original Message -----
>From: "Dr. Steven Rogak" <rogak@mech.ubc.ca>
>To: <ronallarson@qwest.net>; <elk@wananchi.com>
>Sent: Friday, June 06, 2003 1:17 AM
>Subject: Cookstoves as an student design project?
>
>
>> Dear Ron and Elsen:
>> I am considering running a mechanical engineering design project in
>> which the students would build/test/improve a cookstove appropriate to a
>> particular developing country. There seems to be enough technical
>> information on this topic to get the students going, but the big question
>> seems to be getting the stove into use or at least getting the
>> information to potential users. My preference is to have the students
>> work on the design for a very specific location, but failing this, the
>> students might disseminate their design evaluations through crest or
>> other organization.
>>
RWL: 1) I really want to encourage your running this design project.
There are several huge world problems that can be addressed and I believe
your students will find plenty to be challenged by.

2) I agree that there is plenty of technical information available. The
challenge is to solve the design problems cheaply.

3) The specific location problem is a great idea. I think we have plenty
of "stoves" contributors to assist in most parts of the world.

4) I am sure that the "stoves" list would love to assist in critiquing the
student designs.

5) The experience will be valuable even if the designs are not ultimately
taken up,

>> Do you have any suggestions for linking the student work to end users?
>>
RWL: 1) I suggest the students start with the "stoves" archives and make
contact with several of the "stovers" writing about the needs or solutions
they like the most. No promises, but I think many of us will respond.

2) Look up the "ethos" list - which is very much University oriented,

3) There is a new growing University-oriented organization called
"Engineers Without Borders" - with strong ties into Canada.

4) I would guess that the ASME or several similar groups could provide
leads internationally.

5) A major advantage of working in the University framework can be good
test equipment - something most of us on "stoves" don't have.

6) There are several other stoves groups around the world - that I am sure
you can find through a "Google" search - or noting on "stoves". Look for
HEDON, ARE COP, Energia, etc. At one tie, Canada had a lead role in this
area.

7) When you are ready, I am sure many of us can suggest fundamental design
issues we would like to see addressed.

Best of luck - look forward to working with you. Ron

 

>> Steve Rogak
>> Associate Professor
>> Department of Mechanical Engineering, University of British Columbia
>>
>>
>
>
>

From nariphaltan at SANCHARNET.IN Sun Jun 8 21:14:07 2003
From: nariphaltan at SANCHARNET.IN (nariphaltan)
Date: Tue Aug 10 18:30:25 2004
Subject: Cookstoves as an student design project?
Message-ID: <MON.9.JUN.2003.064407.0530.>

You might look at; http://education.vsnl.com/nimbkar/housenergy.html

There are some interesting ideas for research.

Dr. Anil K. Rajvanshi
Director
Nimbkar Agricultural Research Institute
P.O.Box 44, Phaltan - 415523
Maharashtra, INDIA
Ph: 91-2166-222396/220945

http://www.nariphaltan.org
http://nariphaltan.virtualave.net
E-mail:nariphaltan@sancharnet.in

For discussion on sustainability and spirituality join Yahoo groups
http://groups.yahoo.com/group/suspri
----- Original Message -----
From: "Ron Larson" <ronallarson@QWEST.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, June 09, 2003 6:31 AM
Subject: Re: [STOVES] Cookstoves as an student design project?

> Steven and Elsen:
>
> 1. First thanks to Elsen for replying while I was at the
Approvecho
> meeting.
>
> 2. Because I just sent out a general report on a meeting that
partly
> addresses exactly what you are asking about (student involvement) - and
> because I want to get all "stove" list members thinking this way, I am
going
> public with a message you started in private. I think you will not mind -
> but I apologize if needed.
>
> 3. More notes below - first on Elsen's response and then on your
> questions.
>
> >-----Original Message-----
> >From: elk [mailto:elk@wananchi.com]
> >Sent: Thursday, June 05, 2003 10:56 PM
> >To: Dr. Steven Rogak; ronallarson@qwest.net
> >Subject: Re: Cookstoves as an student design project?
> >
> >
> >Stephen;
> >
> >Getting the right stove to the appropriate user and communicating the
> >information while imparting the motivation to ensure said user
> >actually uses
> >stove in question........ there's a challenge equal to that of the stove
> >design.
>
> (RWL): Agreed. There are not many major success stories to
report. The
> country that has done the best job is China - and a report will be coming
> soon on reasons why. We need to lower costs AND explain the many reasons
> for spending a bit more for a better (more efficient, more healthy, etc)
>
> >
> >Institutional stoves may be easier though. The user possesses a somewhat
> >different set of assessment criteria and a less subjective administrative
> >judgment of the stove is normally made in addition to the actual
> >users- e.g.
> >manager + cook.
>
> (RWL): Agreed. So your students might work in that direction.
One way to
> proceed might be to find successful stoves being used commercially and try
> to figure out how to improve - or just to understand how the success was
> achieved.
> >
> >To this end there's orphanages, refugee centres, schools, clinics and
> >hospitals as well as restaurants and hotels...... and when there's a
> >commercial aspect involved, objectivity is often increased.
>
> (RWL): Agreed
> >
> >Might follow this thread via a church to one of their developing world
> >'feeding centres & the like.
> >
> >BTW- any ideas where I could source very small TEGs (Thermo-electric
> >generators)? I've a budding idea about slapping one of these on the side
of
> >a domestic charcoal 'jiko' here & generating a watt or so to power a
small
> >LED cluster hanging over the cook-pot........ might be an idea for one
of
> >your students to investigate. Now THAT wouldn't be a hard sell here! I'd
be
> >happy to get involved. I've the .8 watt white 9-LED clusters already.
>
> (RWL): An interesting area for student work - not much has gone
on here.
> >
> >Ronal- there's been some discussion about Russian-made TEGs on the
> >list- did anyone ever mention sources?
>
> (RWL): I have a friend doing work here - and can get him
involved if
> needed when anyone is going big. otherwise - look at
> http://www.peltier-info.com/
> >
> >Be happy to discuss further. If the cost can be kept 'way down, I could
get
> >funding for production & dissemination on a commercial basis easily
enough.
> >A very big need for lighting here & it'd be a neat tie-in to our
> >(Chardust's) eco-friendly charcoal manufacture.
>
> (RWL): See also my notes sent out earlier today - which mention
work by
> Dean Still on this lighting issue.
> >
> >rgds;
> >elk
> >
> >--------------------------
> >Elsen L. Karstad
> >elk@wananchi.com
> >www.chardust.com
> >Nairobi Kenya
> >
> >
> >
> >----- Original Message -----
> >From: "Dr. Steven Rogak" <rogak@mech.ubc.ca>
> >To: <ronallarson@qwest.net>; <elk@wananchi.com>
> >Sent: Friday, June 06, 2003 1:17 AM
> >Subject: Cookstoves as an student design project?
> >
> >
> >> Dear Ron and Elsen:
> >> I am considering running a mechanical engineering design project in
> >> which the students would build/test/improve a cookstove appropriate to
a
> >> particular developing country. There seems to be enough technical
> >> information on this topic to get the students going, but the big
question
> >> seems to be getting the stove into use or at least getting the
> >> information to potential users. My preference is to have the students
> >> work on the design for a very specific location, but failing this, the
> >> students might disseminate their design evaluations through crest or
> >> other organization.
> >>
> RWL: 1) I really want to encourage your running this design
project.
> There are several huge world problems that can be addressed and I believe
> your students will find plenty to be challenged by.
>
> 2) I agree that there is plenty of technical information
available. The
> challenge is to solve the design problems cheaply.
>
> 3) The specific location problem is a great idea. I think we
have plenty
> of "stoves" contributors to assist in most parts of the world.
>
> 4) I am sure that the "stoves" list would love to assist in
critiquing the
> student designs.
>
> 5) The experience will be valuable even if the designs are not
ultimately
> taken up,
>
> >> Do you have any suggestions for linking the student work to end users?
> >>
> RWL: 1) I suggest the students start with the "stoves" archives
and make
> contact with several of the "stovers" writing about the needs or solutions
> they like the most. No promises, but I think many of us will respond.
>
> 2) Look up the "ethos" list - which is very much University
oriented,
>
> 3) There is a new growing University-oriented organization called
> "Engineers Without Borders" - with strong ties into Canada.
>
> 4) I would guess that the ASME or several similar groups could
provide
> leads internationally.
>
> 5) A major advantage of working in the University framework can
be good
> test equipment - something most of us on "stoves" don't have.
>
> 6) There are several other stoves groups around the world - that
I am sure
> you can find through a "Google" search - or noting on "stoves". Look for
> HEDON, ARE COP, Energia, etc. At one tie, Canada had a lead role in this
> area.
>
> 7) When you are ready, I am sure many of us can suggest
fundamental design
> issues we would like to see addressed.
>
> Best of luck - look forward to working with you. Ron
>
>
>
> >> Steve Rogak
> >> Associate Professor
> >> Department of Mechanical Engineering, University of British Columbia
> >>
> >>
> >
> >
> >
>

From rdboyt at YAHOO.COM Mon Jun 9 07:37:10 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:25 2004
Subject: photoelectrochemical technology
Message-ID: <MON.9.JUN.2003.043710.0700.RDBOYT@YAHOO.COM>

Stovers all:

It is with great enthusiasm that I bring to the
attention of this forum wonderful news of a technology
that I believe may prove to be a primary contributor
to the search for long term sustainable energies. As
such, it should be of particular interest to stovers.
While I cannot yet understand or describe this
technology in precise detail, on the surface at least,
it appears to promise to surpass even the potentials
of high temperature depolymerization and cold fusion.

While some understanding and attempts to utilize this
technology are relatively new, its basic principles
are ancient. In essence, it relies upon a remarkably
complex interconnection of physics, chemistry and
geometry that uses the sun's energy to
photoelectrochemically break apart molecules of water
and carbon dioxide. It then combines the resulting
hydrogen and carbon to produce a myriad of
hydrocarbons. The technology combines some of these
hydrocarbons to form solids of such great dimensions
and strength that they may be used to build sizable
architectural structures. Other uses for the
hydrocarbons may be found in the manufacture of
plastics, adhesives, foods, medicines, solid, liquid
and gaseous fuels, and countless other products.
Surprisingly, the technology derives its carbon
dioxide directly from the air, then releases excess
oxygen back into the air.

Certainly, the most remarkable feature of this
technology is the advanced development of
pre-programmed controls that permit it to build copies
of itself, much like a CNC lathe which can be
programmed to totally reproduce itself, complete with
programming. The structure it builds automatically
repairs itself if damaged and thus requires very
little maintenance. This structure forms a rigid
framework shaped to hold a multitude of solar cells in
such a manor as to efficiently collect sunlight,
search for the carbon dioxide. It also builds and, if
necessary repairs, if necessary replaces its solar
cells. These cells and, indeed, the entire structure
are totally biodegradable.

Admittedly, the support structures are tall and do
impose themselves upon the landscape, a bit like
windmills. But this may at least be partially
forgiven, for in fact, some people find them to be
somewhat aesthetically pleasing. In large groupings,
they do take up a lot of space, but it can be shown
that these groupings can be arranged to actually
modify local climates, reducing the extremes of wind,
temperature, humidity, and even precipitation. Of
particular interest to stovers should be the welcome
news that these structures collect and store great
quantities of chemical energy that can be released as
heat and light when burned. One last, and perhaps
most important observation is that this appears to be
a technology that promises to be truly long-term
sustainable.

Cryptically yours,
Dick Boyt
Pottershop Hollow Tree Farm
20479 Panda Rd
Neosho, MO 64850
U.S.A.

__________________________________
Do you Yahoo!?
Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
http://calendar.yahoo.com

From kchisholm at CA.INTER.NET Mon Jun 9 08:37:12 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:25 2004
Subject: photoelectrochemical technology
Message-ID: <MON.9.JUN.2003.093712.0300.KCHISHOLM@CA.INTER.NET>

Dear Richard

Your description of the phytochemical technology system is indeed
appreciated. All too often we look for the new and the different, rather
than seeking to utilize that which is all around us. It is perhaps a
phenomenon related to the ones where we never miss the water until the well
runs dry, or never appreciate our health until we lose it.

Kevin Chisholm
Downtown Barrachois
Cape Breton, NS

----- Original Message -----
From: "Richard Boyt" <rdboyt@YAHOO.COM>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Monday, June 09, 2003 8:37 AM
Subject: [STOVES] photoelectrochemical technology

> Stovers all:
>
> It is with great enthusiasm that I bring to the
> attention of this forum wonderful news of a technology
> that I believe may prove to be a primary contributor
> to the search for long term sustainable energies. As
> such, it should be of particular interest to stovers.
> While I cannot yet understand or describe this
> technology in precise detail, on the surface at least,
> it appears to promise to surpass even the potentials
> of high temperature depolymerization and cold fusion.
>
> While some understanding and attempts to utilize this
> technology are relatively new, its basic principles
> are ancient. In essence, it relies upon a remarkably
> complex interconnection of physics, chemistry and
> geometry that uses the sun's energy to
> photoelectrochemically break apart molecules of water
> and carbon dioxide. It then combines the resulting
> hydrogen and carbon to produce a myriad of
> hydrocarbons. The technology combines some of these
> hydrocarbons to form solids of such great dimensions
> and strength that they may be used to build sizable
> architectural structures. Other uses for the
> hydrocarbons may be found in the manufacture of
> plastics, adhesives, foods, medicines, solid, liquid
> and gaseous fuels, and countless other products.
> Surprisingly, the technology derives its carbon
> dioxide directly from the air, then releases excess
> oxygen back into the air.
>
> Certainly, the most remarkable feature of this
> technology is the advanced development of
> pre-programmed controls that permit it to build copies
> of itself, much like a CNC lathe which can be
> programmed to totally reproduce itself, complete with
> programming. The structure it builds automatically
> repairs itself if damaged and thus requires very
> little maintenance. This structure forms a rigid
> framework shaped to hold a multitude of solar cells in
> such a manor as to efficiently collect sunlight,
> search for the carbon dioxide. It also builds and, if
> necessary repairs, if necessary replaces its solar
> cells. These cells and, indeed, the entire structure
> are totally biodegradable.
>
> Admittedly, the support structures are tall and do
> impose themselves upon the landscape, a bit like
> windmills. But this may at least be partially
> forgiven, for in fact, some people find them to be
> somewhat aesthetically pleasing. In large groupings,
> they do take up a lot of space, but it can be shown
> that these groupings can be arranged to actually
> modify local climates, reducing the extremes of wind,
> temperature, humidity, and even precipitation. Of
> particular interest to stovers should be the welcome
> news that these structures collect and store great
> quantities of chemical energy that can be released as
> heat and light when burned. One last, and perhaps
> most important observation is that this appears to be
> a technology that promises to be truly long-term
> sustainable.
>
> Cryptically yours,
> Dick Boyt
> Pottershop Hollow Tree Farm
> 20479 Panda Rd
> Neosho, MO 64850
> U.S.A.
>
>
> __________________________________
> Do you Yahoo!?
> Yahoo! Calendar - Free online calendar with sync to Outlook(TM).
> http://calendar.yahoo.com

From dstill at EPUD.NET Tue Jun 10 03:23:39 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:25 2004
Subject: ETHOS Stove Testing and Design Seminar
Message-ID: <TUE.10.JUN.2003.002339.0700.DSTILL@EPUD.NET>

Dear Friends,

Ron mentioned the seminar and I am following up to say that we are crunching
numbers and will have something to report in about a week... I had a great
time. Learned 5 things which is close to a record for a week...Larry
Winiarski ran his 1960 Ford pick-up on wood gas, which had a few folks
snapping pictures! We ran three tests each on the Vesto, Juntos, Turbo,
Rocket, Lanny's, Ron's pyrolizers, open fire. We also got continuous CO
readings in a enclosed room while using each stove.

One of the valuable lessons that the week taught us was how to improve the
testing. Dale Andreatta and Tami Bond are helping us to get ready for the
next seminar.

The sandwiches were great, coffee hot, weather lovely, Joe and Allen (ISU)
(MU) danced with the prettiest girls in Eugene. I hope that Morgan and Jesse
caught lots of fish on their way back to Colorado (CSU)! Rosalie (HSU) will
be going with us to Honduras to learn how to commercially disseminate
stoves.

Results to follow.

Best,

Dean

From enecon_jfb at HOTMAIL.COM Mon Jun 9 19:52:01 2003
From: enecon_jfb at HOTMAIL.COM (Jim Bland)
Date: Tue Aug 10 18:30:25 2004
Subject: Polyethylene and PVC separation
Message-ID: <TUE.10.JUN.2003.095201.1000.ENECONJFB@HOTMAIL.COM>

Polyethylene will float on water (s.g. 0.91 - 0.96), PVC will sink (s.g
1.2 - 1.55).

Regards,

Jim

Enecon Pty. Ltd.
Level 2, 35 Whitehorse Rd., Deepdene VIC 3103, Australia
PO Box 555, Deepdene DC VIC 3103, Australia
Tel: +61-3-9817 6255
Fax: +61-3-9817 6455
www.enecon.com.au
----- Original Message -----
From: Roberto Escard? <robertoescardo@ARNET.COM.AR>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Saturday, June 07, 2003 5:06 AM
Subject: [STOVES] Polyethylene and PVC separation

Does anybody know about a cheap and simple method to separate PVC from
polyethylene? We tested paper - poliethilene - sawdust briquettes and thet
burn very well, but PVC contamination is a danger. Thanks
Roberto.

From tmiles at TRMILES.COM Mon Jun 9 20:25:34 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:25 2004
Subject: [ethos] Stoves for Rice Hulls? Coconut Husks? Coconut copra
meal?
Message-ID: <MON.9.JUN.2003.172534.0700.TMILES@TRMILES.COM>

Bryan,

Rice hull stoves, burners and gasifiers abound. All the more reason to ask
this group.

Search for "rice" on the Biomass Cooking Stoves website and you'll find
several references. Also do a search on "coconut" on the stoves site.
http://www.repp.org/discussiongroups/resources/stoves/ And search
www.repp.org for rice husk stove

Also look at www.arecop.org and www.repp.org

Rice hull gasification has also been the subject of considerable
development. Rob Bakker at the International Rice Research Institute is
involved in field operations but he has a strong background in gasification
at US Davis with professor Bryan Jenkins. Contact Bryan (Agricultural and
Biological Engineering Department) who has years of experience with rice
hull gasification in the Philippines and elsewhere. Of course there is the
experience in India with rice hulls. See my list of gasification references
on REPP at http://www.repp.org/articles/static/1/1011975339_7.html and
http://crest.org/discussiongroups/resources/gasification/200kWCHP.html
It seems like there has been a trail of US gasification exports going to the
Philippines for many years to set up small systems but I have no idea where
they might be. I think one of Doug William's 14 NEI Fluidyne Pacific Class
Gasifiers (New Zealand) was used on coconut hulls but you'd have to ask him.
http://www.fluidynenz.250x.com/

As you will find on the Stoves and ARECOP websites that IRRI also has their
own rice husk stove based on the Vietnamese Lo Trau which has spawned
similar rice stoves in kenya, Peru and most recently used by REAP in their
Mayon turbo stove. A diagram of the Lo-trau can be seen at:
http://footsteps.tearfund.net/english/pdf/21e_mid.pdf

Rice husks in Peru are reported in Boiling Point No. 42, 2002. (ITDG)

I would depend on the coconut husk burner for reliability. Waste heat from
the producer gas engine is a nice idea but often not reliable as a sole
source.

When a material is valuable as a meal it can also be pelletized. The main
concern is wheter the added cost and complexity of pelletizing can be paid
for by the feed value. Usually it does not unless the meal is combined with
other feedstuffs to make a whole ration feed. The value of copra meal is as
a substitute for imported corn and soy bean. UP Los Banos found that copra
meal can be used up to 40% in pig rations. If that can be done commercially
there is no need to pelletize.
http://www.stii.dost.gov.ph/tekno/book1/book1_62.htm There would not seem to
be an export market.

Hope this helps,

Tom

----- Original Message -----
From: "Bryan Willson" <Bryan.Willson@colostate.edu>
To: <STOVES@LISTSERV.REPP.ORG>; <ethos@vrac.iastate.edu>; "Ron Larson"
<ronallarson@qwest.net>
Sent: Monday, June 09, 2003 8:08 AM
Subject: [ethos] Stoves for Rice Hulls? Coconut Husks? Coconut copra meal?

> Forgive me if these topics have already been addressed. Hard to imagine
> stove / fuel topics which haven't been covered.
>
> I just returned from a trip to the Philippines on our 2-stroke engine
> conversion project and made a side trip to the island of Panay to visit a
> project where one of my PhD students will be spending a year. The project
> is located in Ibajay, outside of Kalibo, at a cooperative organized by
1000+
> coconut growers. It involves gasifying coconut husks to run a 15 kW
engine
> which powers machinery to allow extraction of coir - the fibrous material
> which surrounds the coconut. The coir is then spun into twine which is
> woven into matting for export. That's a gross oversimplification of a
> fascinating, integrated project, but works to set the stage for my
> questions.
>
> Several stoves questions came up during the visit:
>
> 1) The group us burning coconut husks to dry the coconut copra (the "meat"
> of the coconut) so it can be pressed to remove the oil. The quality of
the
> oil is much higher if the copra is heat-dried than air-dried. Currently,
> heat for drying comes from a simple diffusion burner in which coconut
husks
> are burned. Wasn't there a thread some months back on coconut-husk
stoves?
> Ideally, the heat for drying will ultimately come from waste heat from the
> producer gas unit and/or the producer gas engine so this question may
> ultimately become moot. If so, then the coconut shells are widely
available
> local fuel and a clean coconut-husk stove is needed.
>
> 2) After expelling the oil from the copra, oil-rich copra meal is left.
It
> occurs to me that this could be pressed into high quality fuel pellets.
Any
> thoughts on this? Currently the copra meal is sold as animal feed as it
is
> reasonably high in protein. What is the "bigger picture" here? Assuming
> that the meal is available either as a high quality fuel or a high quality
> animal feed - which is more "valuable" in terms of human health?
>
> 3) The group is interested in stoves and has designed a rice-hull burner.
I
> haven't seen it in action but it appears to be pretty basic and I'm told
> it's pretty smoky. Has this issue been addressed on the list-serve? Is
> there any prognosis of compacting / densifying the rice husks into
pellets,
> or is there a clean way to burn them in their raw form?
>
>
> Sorry for raising 3 somewhat dissimilar questions at once. Please feel
free
> to comment on any of issues.
>
>
> Thanks!
>
> - Bryan Willson
>
>
>
> Dr. Bryan Willson
> Professor of Mechanical Engineering
> Research Director, Engines & Energy Conversion Laboratory
> Department of Mechanical Engineering
> Colorado State University
> Fort Collins, Colorado 80523-1374
> Phone: (970)-491-4783
> Mobile: (970)-227-5164
> Text Messaging: 9702275164@mobile.att.net
> FAX: (970)-491-4799
> EECL Web Site: www.engr.colostate.edu/eecl/
> Alternate Engines Lab Contact: Ms. Kathy Nugent - (970)-491-4785
>
>
>

From robertoescardo at ARNET.COM.AR Tue Jun 10 15:58:29 2003
From: robertoescardo at ARNET.COM.AR (=?iso-8859-1?Q?Roberto_Escard=F3?=)
Date: Tue Aug 10 18:30:25 2004
Subject: Fw: [STOVES] Polyethylene and PVC separation
Message-ID: <TUE.10.JUN.2003.165829.0300.ROBERTOESCARDO@ARNET.COM.AR>

Richard:
I tried to send the mail to directly to you, but it is rejected as spam.
Roberto.
----- Original Message -----
From: Roberto Escard?
To: rstanley@legacyfound.org
Sent: Tuesday, June 10, 2003 4:13 PM
Subject: Fw: [STOVES] Polyethylene and PVC separation

 

----- Original Message -----
From: Roberto Escard?
To: rstanley@legacyfound.org
Sent: Tuesday, June 10, 2003 3:44 PM
Subject: Re: [STOVES] Polyethylene and PVC separation

Estimado Richard:
First the answers:
1) The briquette makers (BM) are getting most of the plastics from the waste dumps. In our country there is common to use PVC (not polyetylene) bags for garbage disposal I instructed the BM not to use black o grey bags (usually PVC) only the white or translucent ones (sure not PVC), but I am not sure they are following my advice.
2) They are making two models of briquettes:
A) A cilyndrical, solid, 15 centimeters long, 6 centimeters diameter, using starch, or waste flour or potatoes skin as binder. Combustible material is usually a mix of sawdust, wood shavings and paper. Wet process at ambient temp, pressed at 5 kilos/sq centimeter. (70 psia) That is the "clasic" briquete here (It resembles a wood log) not a very eficient one indeed.
B) Cubitos (little cubes) that I introduced a few months ago. There are 10 centimeters cubes, with a 3 centimeters dia holow core. (More or less the same size as your briquettes I guess) We do not use any binder but more paper than in "clasic".
Combustible is a mix of paper, wood shavings, leaves and wood chips.
Wet process, I had to calculate the pressing pressure, I guess more or less the same as in the classical ones.
In both cases we cut the plastic film in approximately 2 X 4 centimeters pieces. I told the BM not to add "very much" plastic in the briquettes, but I do not know how much there are actually using.
Our chip makers live in a peri urban zone in a touristic area, and as you say, the plastic bags pose an aesthectic problem: The zone is quite windy and the bags spread in big areas around the dumps. What I plan to do is to convince the local authorities to pay the waste "recovers" (How are they called in english?) to pick the bags and give they to te BM, once we are sure about their use.
BTW: Briquette making is a recent activity in our area (patagonian andes) there is plenty of wood in the zone (national forests) but not easily available. There are only a dozen of groups (mostly NGO?s) working in the field now, but I suposse they will be a strong grow in the near future, many people who used LPG can not afford it now due to price increases and the economic situation and are stepping down the energy ladder.
Some questions to you:
1) The ratio 1 bag/125 gram (7% dry basis?) briquette is the result of burning tests or of the availability of polyethylene? Have you any info about the maximum possible plastic content? (I tried to make pure polyethylene - clay briquettes, but I could not make enough test, it seems to work)
2) How do you crush the bags to cornflake size?
3) Just curiosity: Are there black polyethylene film? I have never seen it, no one makes it in our country.

Thanks a lot for your advices, get in touch
Kind regards
Roberto.

 

----- Original Message -----
From: Richard Stanley
To: Roberto Escard?
Sent: Monday, June 09, 2003 3:44 AM
Subject: Re: [STOVES] Polyethylene and PVC separation

Estimado Roberto,
I offer you two questions and some ideas about plastic bag use in briquettes
<snip>

From psanders at ILSTU.EDU Wed Jun 11 01:11:50 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:25 2004
Subject: Stoves Grand Challenges
Message-ID: <WED.11.JUN.2003.001150.0500.PSANDERS@ILSTU.EDU>

Stovers, (list moderators for ETHOS, HEDON, ARECOP, and GTZ-ProBEC might
want to forward this to their list members.)

Have you heard about the US$200 million from the Gates Foundation about
Global Challenges in World Health? Well worth knowing about. You can go
to http://www.grandchallengesgh.org/
for all the info. It relates to health of people in the developing countries.

Basically, this is ONLY a call for 2-page recommendations of topics that
will undergo selection to specify later (August) the topics for requesting
proposals for funding. Those who send recommendations that are selected
will NOT have an advantage over others. The deadline is 15 June 2003 (this
week).

The recommendations must be for "a discrete scientific or technological
innovation," NOT for a "problem."

Tom Reed and I have prepared one about stoves. There is plenty of breadth
for our various stoves projects, and the first page is almost "generic" in
case you want to use it for a recommendation of your own.

Our "discrete innovation" concerns the small gasifiers, and is most of the
second page. And a key objective is to get major funding for a Stoves
Laboratory and personnel and cooperation internationally. You can read
below what I will be sending.

I will be sending to the Grand Challenges organizers in very soon, but I
have one day to spare to show it to you. If you can think of some why to
help get this or other stoves issues included on the final list of Grand
Challenge topics, please try. Perhaps comments from the leaders of the
various groups of stove people could give an endorsement.

If we get a stoves topic onto the list of selected Grand Challenges, you
will all be contacted (via the Stoves list serve) for suggestions on how to
structure the research grant proposals (plural).

So here it is, but in e-mail formatting, not as an attachment. I
"pre-checked" this message with a copy to myself, and the content is
readable, and the hot-links all work.

THIS IS A NEAR-FINAL DRAFT !!!!!! One change will probably be the Web
address for Reference # 4 (about my work with the Juntos
gasifiers.) Also, I can still put in one more reference (limit is 5).

I hope you enjoy this. Paul

Title: "Top-Lit Up-Draft - TLUD" Gasifier Technology for Improved Cook
Stoves (ICS) to Reduce Indoor Air Pollution (IAP) and Thereby Avoid Lower
Respiratory Infections (LRI)
A recommendation to the "Grand Challenges in Global Health" initiative of
the Bill and Melinda Gates Foundation.
Prepared by Paul S. Anderson and Thomas B. Reed. Submitted in
mid-June 2003.

2-page limit:
Short title: Improved Cook Stoves (ICS) and TLUD Gasifier Technology to
Avoid Lower Respiratory Infections (LRI).
Summary: Lower Respiratory Infections (LRI) form the second worst health
problem for developing countries. The solution is avoidance of the cause,
a smoky kitchen. People must cook; so one solution is an appropriate
clean-burning stove that is sustainable with the household's financial
limitations and available fuels. "Top-Lit Up-Draft - TLUD" gasifier stoves
are a new technology securely founded on historically established pure
science concerning the control of the air-fuel ratio. The roadblocks to
achieving the benefits of TLUD gasifiers relate to "time-on-task" true
scientific research with reasonable funding. Then the already operational
ways to disseminate Improved Cook Stoves (ICS) can be implemented. [We
recognize that other innovations for ICS should also be considered as
rigorous research topics to reduce LRI.]
1. The # 2 health problem for high-mortality developing countries:
Lower Respiratory Infections (LRI) form a group that is classified by the
World Health Organization (WHO) as the second worst category of disease and
injury that impacts the "Disability-Adjusted Life Years - DALYs" of people
in the poorest countries of the world. In The World Health Report 2002
(WHO, 2002, Annex Table 14 on page 232 is Ref
#1: http://www.who.int/whr/2002/whr2002_annex14_16.pdf ), for the High
Mortality Developing Countries (HMDC), LRI with 8.2% of DALYs is second
only to HIV/AIDS (9.0% DALYS) and worse than Diarrhoeal Diseases (6.3%
DALYs) and even the combined Childhood Cluster Diseases (5.5% DALYs).
The risk factors that cause these leading diseases are in the cited
table. Concerning LRI in these poorest countries, the four named factors
include two (zinc deficiency and underweight) that are multi-faceted
nutritional problems, and one (tobacco) that is an "individual choice"
mainly of adult men. The other risk factor that clearly has the most
direct impact on LRI is "indoor smoke from solid fuels," elsewhere referred
to as Indoor Air Pollution (IAP). Note that "indoor smoke from solid
fuels" (or IAP) is the fourth worst risk factor (with 3.7% DALYs) for the
HMDC, and is the eighth worst risk factor (1.9% DALYs) in the low mortality
developing countries (LMDC) (Annex Table 15).
2. Realities, roadblocks and rationale concerning possible solutions:
Pre-historic people brought fire into their caves, and IAP began to cause
health problems. Still today, about two billion people still cook every
meal with solid, biomass fuels (sticks, dung, agricultural wastes, etc.) on
the proverbial "three-stone fire" or on "Improved Cook Stoves - ICS" that
are only slightly better.
On the other hand, modern developed societies, to escape the undesirable
aspects of burning biomass in open fires or in low-quality stoves, have
used science and technology to make two simultaneous adjustments: A. They
have shifted to processed and refined fuels such as propane, kerosene,
"natural" gas, and electricity, and B. they have developed many combustion
devices (commonly called "stoves") that can burn those fuels cleanly, that
is, with a minimum of emissions and/or with efficient venting via
chimneys. The scientifically determined and technologically controlled
mixing of the air and fuels to obtain optimal combustion with minimal
harmful emissions is the ultimate key to clean burning and consequent good
health.
Although we can praise the valiant efforts by (some) governments, agencies,
and individuals to bring to the poor the established solutions for modern
cooking (including rural electrification, transport/supply of modern fuels,
subsidized stoves, and stove-use training programs), those efforts are not
viable solutions. The costs are great, the pace is extremely slow, and the
solutions are neither sustainable nor appropriate for the realities
(minimal finances, precarious housing, etc.) of many people in the
developing world. Furthermore, the processed fuels are mainly from fossil
sources known to be finite and eventually insufficient.
The solution we seek is a clean-combustion-stove that is "sustainable" and
"appropriate" for the developing world. It must be low cost, capable of
using renewable biomass fuels for very small fires, and "user-friendly" for
people with little education. Rigorous science is needed to prove that any
candidate stove and its fuels are indeed clean burning with correct
air-fuel ratios throughout the duration of the combustion.
Two main roadblocks impact all of the activities concerning innovations for
Improved Cook Stoves (ICS): A) fragmented efforts and B) the lack of
essential scientific measurements about air-fuel ratios and resultant
emissions. The availability of scientific measurements would document and
guide the experiments that will identify the correct air-fuel ratios for
development of technology to accomplish the air-controls necessary for the
diverse biomass fuels that will be used in the developing
countries. Although a few universities have good laboratories for some
stoves issues, none is both equipped and available (adequately funded) to
focus rigorously (exclusively) on the issues of emissions and air-fuel
ratios for stoves and biomass fuels that are appropriate and sustainable
for developing countries. Measurement techniques exist; pockets of
experimentation function; scientists know a great deal about fires and
fuels for developed societies. Even Internet List-Serves and associations
(HEDON, ARECOP, STOVES-REPP, ETHOS, GTZ/ProBEC) maintain contact between
the ICS enthusiasts found on every inhabited continent. (Ref. #2: Go to
the REPP site and do a "Search this site" on any of the names found in this
current document: http://www.repp.org/discussiongroups/resources/stoves/
). Almost everyone's work reported there is voluntary or is a "side
interest" of employment. Some funding has kept things going, but major
funding for a concerted effort about the air-fuel ratios and ICS-related
fire-needs of developing societies is now and has been long absent.
3. Sound scientific foundations for "TLUD gasifier" advances in
Improved Cook Stoves-ICS:
[Although various innovations for ICS should also be considered as
rigorous research topics, we focus on one here.]
A world-recognized expert on gasification of biomass, Dr. Thomas B. Reed,
has proposed and done initial testing on an innovative way to burn
biomass. He initially called it an "Inverted Down-Draft IDD" gasifier; we
currently call it a "Top-Lit Up-Draft TLUD" gasifier. [Note: The
terminology is not yet established, but large, industrial gasifiers can be
classified as "Top-Lit Down-Draft TLDD" or "Bottom-Lit Up-Draft BLUD," as
is a standard wood fire.]
The fundamental characteristics of "Top-Lit Up-Draft TLUD"
gasifiers are:
One: A controllable amount of primary air enters at the bottom and is
drawn upwards through a chamber filled with dry biomass. (Such biomass
includes wood chips, corncobs, briquettes/pellets, dung chips, and coconut
husks.)
Two: A small fire is lit on the top of the biomass, so the fire smolders
(pyrolysis at relatively low heat) because of the limited oxygen reaching
it from the bottom. All of the oxygen is consumed, so the smoke is hot and
without oxygen.
Three: A controllable amount of secondary air enters into the hot smoke,
and the smoke plus oxygen is highly flammable, producing a "gas flame" that
can be used for cooking, heating, etc.
In short, the TLUD gasifiers intentionally create emissions (smoke) that
are then combusted in controlled conditions to replicate a gaseous fire
with minimal emissions. The by-product is charcoal that can also be burned.
Dr. Reed's moment of inspiration about TLUD gasification was in 1985. The
initial laboratory testing produced a paper with Dr. Ronal Larson entitled
"A Wood-Gas Stove for Developing Countries" (Reed and Larson, 1996, Ref. #
3: http://www.repp.org/discussiongroups/resources/stoves/Reed/T1.htm ).
In more recent years, perhaps twenty people in relative isolation have
undertaken experimentation and development of TLUD gasifiers. One of them,
Dr. Paul S. Anderson, (Ref. # 4:
http://www.repp.org/discussiongroups/resources/stoves/Anderson/Anderson_Juntos.html
) has made about 50 different TLUD gasifiers using refuse tin cans up
through quality sheet-metal products, some with blowers and fans. The
experiences clearly show the soundness of the scientific and technical
foundation of the small-scale TLUD biomass gasifiers.
Many variables can impact the TLUD gasifiers: air-fuel ratios, the sizes
and positions of the primary and secondary air holes, pre-heating of air,
natural vs. chimney-induced vs. fan-forced draft, stove sizes, insulation,
fuel types, fuel sizes, efficiencies, emissions, alternatives for stove
controls, etc. Not one variable has been scientifically examined
thoroughly for optimization. For this we need at least one major
laboratory created or up-graded specifically to undertake the TLUD gasifier
experimentation. Also, we want the parameters of the testing to be
identified and guided by the combined efforts of the best thinking that can
be brought together at the laboratory and/or at highly specific workshops
and seminars. As we overcome those two roadblocks, the following
anticipated scientific and technical advances could be expected:
a. Obtain scientific measurements of the performance of the
different existing ICS stove technologies as used in developing
societies. These important benchmarks have not been gathered in comparable
and controlled conditions.
b. Determine the optimal ("least emissions") air-fuel ratios, and the
placement and timing of the air entrance into the TLUD gasifier stoves of
different sizes for each of many potentially important specific biomass fuels.
c. Establish the relative and absolute values of raw versus
partially-processed versus fully-processed or refined biomass fuels,
resulting in better uses of fuels for different purposes, plus human and
environmental health benefits.
d. Provision of guidelines about materials and designs for
TLUD gasifier stove construction, with attention to costs and benefits for
serving the needs of the major levels of development within the developing
countries.
4. Impact of solving the Grand Challenge of indoor air pollution:
a. Industries (and jobs) will be created to make and market
the stoves for the appropriate contexts of the target communities. The
stoves will range from "local-made extremely simply inexpensive single
purpose models" to sophisticated industrialized models with heat sensors,
timers, blowers, and multiple purposes (boil, fry, bake, roast,
etc.). TLUD gasifiers will have many variations: heat radiating (for
warmth) and heat insulated (for hot environments); specific to available
biomass fuels of various qualities; and industrial sizes to serve small
bakeries, processing factories, and other heat-powered facilities, perhaps
even to generate electricity via Sterling engines or thermoelectric devices.
b. Respiratory health problems from indoor air pollution in poor
societies will diminish greatly. TLUD gasifiers are for disease
prevention, which is better than curative health care. Stoves-safety
should also improve.
c. Reductions in OUTdoor air pollution will also occur,
including less of the "Asian Brown Cloud ABC."
d. Efficiency and variety of biomass fuels should
increase. Some literally waste biomass or even environ-mental pollutants
could become fuel resources. Processing and refinement of biomass will
also occur, according to needs.
e. When fuels burn better and can be obtained closer to home,
the added advantage of reduced drudgery labor for women and children will
also encourage more rapid acceptance and use.
f. The scientific and technical advances discussed above will
be immediately placed into the prototypes and early production models that
will be placed into actual communities to gain feedback on
user-friendliness and other "non-laboratory" factors. Therefore, the
advances are only a single step away from implementation into functional
stoves.
5. Feasibility of implementation:
The proposed solution(s) are, by definition, to have low-cost,
local, and sustainable implementation. Governments, agencies and
individuals around the world are anxiously poised to implement appropriate
solutions to the combined problems of indoor air pollution, deforestation,
and domestic energy. Current funding for ICS efforts will shift toward the
solutions scientifically proven to work. We will nurture our strong links
to the ICS specialists who know the realities of domestic cooking and
heating practices in the developing world. Social change in developing
countries can be slow, but when new stoves show immediate improvement of
the indoor air quality and use of more easily obtained and less expensive
fuels, social change can and will occur.
6. Other comments: We have much more to say, but no available space. We
will answer any questions you have. We will provide solutions. PSA & TBR

######## end ######

 

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From ventfory at IAFRICA.COM Wed Jun 11 04:55:58 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:25 2004
Subject: Thoughts - Prototype clay biomass-pyrolyzing stove
Message-ID: <WED.11.JUN.2003.105558.0200.VENTFORY@IAFRICA.COM>

Ron and Richard (and stovers),

Any progress with your clay type pyrolyzing stove? I think it is a very good idea, has any other stovers tried doing that?

Chimney
If it is clean burning like this new technology allows, does it need a fixed chimney? Small stoves are preferred for their portability. The way I understand it, the higher the chimney (or internal chimney) the higher the resultant draft, so for start-up that is OK until you have to turn it down for pot simmering. Controlling primary air can attempt to reduce the draft and therefore the emission temps at the exit point. It is not advisable to alter the airflow to achieve lower exit temperatures in a pyrolyser or gasifier as it will affect the required A/F ratios. One would have to constantly adjust the primary air to counteract high draft created by the fixed chimney. I do not see a primary air control in your prototype though. I suppose that is generally why an internal chimney is preferred, it gives you a high natural draft (by selecting a higher chamber) without having to apply chimneys to it.

If you then dump the external chimney the internal chimney below the pot will give you the required draft in any case. Tom R mentioned "it is also useful to limit the flow of gases upward with a bluff body so that you get a ring of heat and better draft. The gases from that area of charcoal (biomass) can't fill the upper chamber, and so result in instability as some gases rise and others fall."

Your pot will act as a bluff body, the areas along the side of the pot will aid the draft (and obviously heat transfer), plus at the top where you show the chimney, you could rather utilize this heat by placing a pot on top (two pot stove?). If others disagree I would like to hear about i.e. reasons why it won't work or hard to achieve. I am working on a similar type stove with an oven below and a hob above it, running on charcoal.

Secondary air
If you have your secondary air drawn in from the top near the hob, chances are that it will be pre-heated and contain emission gases with some PIC which is directed back for complete burning. I am encouraged by this method in my trials and think it will make a difference to cleaning up emissions in chimney-less stoves.

Does it pyrolyze biomass yet? I would like to see photos of your current prototype.

Regards

Kobus

From psanders at ILSTU.EDU Wed Jun 11 12:35:35 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:25 2004
Subject: Stoves Grand Challenges
In-Reply-To: <IKEDKFNCEGGOEHHJPHKDMEDCFFAA.Bryan.Willson@colostate.edu>
Message-ID: <WED.11.JUN.2003.113535.0500.PSANDERS@ILSTU.EDU>

Stovers,

Bryan caught the change (on first page, but not on the "submissions" page)

At 08:12 AM 6/11/03 -0600, Bryan Willson wrote:
>Just as an aside - I note that the deadline for submission has been extended
>to July 1.

That does give us more time, and I will not submit today as I had
planned. Also, my 2 pages have over 1900 words, and the limit is 1500. So
I am chopping out, and now have about 1750 words. Anything additional
that goes in will require an equal number of words to come out. Not an
easy task.

I go tomorrow to Oregon for a week and will have at least a day with Dean
Still and Aprovecho.

Notes:
A Grand Challenge (as defined by the funding agency) relates
SPECIFICALLY to "a DISCRETE scientific or technological innovation which
will break through the roadblock that stands between where we are now and
where we would like to be in science, medicine, and public health."
What roadblocks do we face concerning elimination of "indoor smoke
from solid fuel"?
What innovations COULD break a roadblock?

Tom Reed and I are advocating the TLUD (or IDD) small gasifiers as AN
innovation and that the roadblock is lack of understanding of the air-fuel
ratios and their control. Therefore, funding is needed for science and
technology to do the job of understanding and creating a "low-emissions"
domestic stove using biomass in the developing countries. And John Davies
coal gasifier is absolutely in this category and will be cited in the
coming revisions.

I have tried to write the 2-pages (that I sent to you last night) to allow
for other stove innovations, EITHER by themselves OR as part of a TLUD
gasifier effort. For example, low-mass ceramic brick for stove interiors
could be a great help in a TLUD gasifier. And the "Rocket Stove" concept
of inserting fuel with Bottom burning plus air control has great merit,
especially (in my opinion) in conjunction with the TLUD gasifier below (as
seen on the Stoves web pages of my early work). And Crispin's stoves,
which he has come to call "semi-gasifiers", bring additional thoughts to
the process.

But are any of those efforts (or others) singly or together sufficient to
be "a discrete innovation" to get "Improved Cook Stoves - ICS" onto the
list of Grand Challenges for which a "request for proposals" will be
issued? (Please comment on this !!)

As a collection of stove enthusiasts linked by Stoves-REPP, HEDON, ETHOS,
ARECOP, GTZ/ProBEC (and others in China or Russia or somewhere), WE
constitute the greatest assembly of knowledge about ICS. (Moderators
of those and other networks need to communicate about this discussion as
they see fit to their members. And please inform us via the Stoves list
serve about if you are sending those messages.)

But can we get our "topic" on the list of Grand Challenges?

Financially, the cumulative funded proposals for laboratories and
conferences/workshops and other things yet to be proposed could be from 2
to 40 million US$, that being 1% to 20% of the Gates funding. I suspect a
reasonable expectation would be 5 to 10 percent, being 10 to 20 million
dollars, to be used in a 5 to 10 year period.

We should not count our chickens before they are hatched. We do not have a
penny yet. But now is the time for some serious thinking and pre-planning.

Time now to get our act together!!!

Time now for "scientists and engineers" (the "pure" kind who thrive in
laboratories) to come forward. Where are the candidate laboratories? Who
can handle what issues?

Time now to develop FAR BETTER connections between the different
continents, or we will see proposals competing needlessly, with some
winners and some losers, instead of a united team with centers of excellence.

I would also like to see some of the funding identified for "specialty
studies." What comes to mind are the abundant waste cahune nuts in Belize
as a possible fuel.

Tom Reed and Paul Anderson do want to be involved, and we do know the
issues of the TLUD gasifiers and will probably have some
coordination/consulting/dissemination duties. But neither of us expects to
operate laboratories or administer the bookkeeping.

It will be interesting to see what discussion follows about the Grand
Challenges of Stoves in Global Health.

Paul

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From tmiles at TRMILES.COM Sun Jun 15 01:40:12 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:25 2004
Subject: Biomass Cookstoves Weblog 6/14/2003
Message-ID: <SAT.14.JUN.2003.224012.0700.TMILES@TRMILES.COM>

Reports, comments and pictures from the ETHOS Stove Design and Testing
Seminar held June 2-6, 2003 are available on the stoves page at:
http://www.repp.org/discussiongroups/resources/stoves/Ethos/Seminar/ETHOSSem
inar2003.html

For larger frame individual pictures see:
http://www.trmiles.com/stoves/Ethos/Seminar/ETHOSSeminar2003.html
The presentation on my web site has some bugs so I won't transfer the larger
format to REPP.org until July when I have time to format it correctly. To
switch between "rolls" you may have to use the "History" button on Internet
Explorer to go back to the main seminar page.

Information on the development of Lo Trau rice hull stoves in the
Phillippines from REAP and IRRI has also been posted.

Tom Miles

From ronallarson at QWEST.NET Tue Jun 17 14:04:44 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: ceramic stoves
In-Reply-To: <20030617163926.327.qmail@web13203.mail.yahoo.com>
Message-ID: <TUE.17.JUN.2003.120444.0600.RONALLARSON@QWEST.NET>

Hi Dick (cc others). Notes below.

>-----Original Message-----
>From: Richard Boyt [mailto:rdboyt@yahoo.com]
>Sent: Tuesday, June 17, 2003 10:39 AM
>To: Ron Larson
>Subject: Re: ceramic stoves
>
>
>Dear Dr. Larson:
>
>Glad you are home safely, and look forward to more
>reports on your visit to Aprovecho. I appreciate
>greatly your invitation of May 25, 03 to comment on
>your new stove designs. It was your descriptions that
>prompted me to make the drawing which added some of my
>own ideas to yours.
>
>Your description of your work on clay models also
>encouraged me to throw and join several cylinders and
>cones, and to explore the problems of mating them to a
>lining of a light weight insulative clay. This clay
>mix must be formulated to match the drying and firing
>shrinkage of a more rigid strong clay exoskeleton.
>Perhaps a thin outside skin of sheet metal would weigh
>less.
>
RWL: This looks like a very difficult problem. But important. I wish you
luck. I will try to assist as a secondary tester - and recommend Ken Goyer
(with whom I stayed in Eugene) to whom I am also sending this. Finding low
cost means of getting low or zero shrinkage would be a big help in
developing countries.
I want to emphasize how pleased I was to work with "printer plates". These
are probably available in many developing countries and are cheap - and easy
to work with. I think they will stand up well where there is an inner layer
of ceramics - and can be used to make molds.

>I did not request Tom Miles to put my drawings on the
>stove site. It should have been a drawing of one of
>YOUR stoves. I would be happy to make drawings for
>you. I fear that it may appear to you and others that
>I would use your good name to promote my own ideas. I
>regret that I did not notify Tom not to publish my
>drawing, but unless I have offended you, perhaps no
>real harm has been done.
>
(RWL): I was pleased he did and am sure no harm has been done - and I am
not very happy with my designs. I will try to send more comments on what I
learned - but I leave in 40 hours for the ASES meeting in Austin and am
behind.

>I will continue to write you and let you decide what
>should or should not go to Tom. I presently am making
>clay models of a grate. The large-bottomed base I
>proposed is largely to be made up of a lightweight
>clay based insulation, cast perhaps, inside a thin
>metal shell. The small fuel container would be metal
>with a clay liner inside. The cylinder above that
>holds the pot would be strong ceramic, again, perhaps
>inside a metal collar. Outside and inside measurement
>tolerances would be important to make a good seal.
>The embedded primary and secondary air downflow
>(pipes) would be cast into the lightweight insulated
>ceramic body that preheats them. I would form these
>channels from a material that would burn out when the
>main body is fired. Yes, I have too many entry holes.

RWL: Lots of good ideas here. I will send this to Tom. One big lesson I
learned at Aprovecho is that I need to better understand the excess air
implications of the size of the secondary air gap. What I described was
much too large in some cases and too small in others. I need a means of
determining either CO2 or O2 in the exiting flame. So having a means of
varying this air is important (and you have it). I am presently thinking of
three screws holding the upper combustion chamber apart from the lower
pyrolysis chamber. The gap can be varied (in the product testing phase) by
changing the size of these three screws. It is important that there be a
wind shield (and air preheater?) that can be held in place by these three
screws. I am now thinking that it is important that these two chambers be
separable - so that the charcoal can be quickly "extinguished". (But it may
be possible to do this with one solid unit.)

> I like your idea of controlling holes with plugs.
>The cap above the pot holder would be insulative clay.
>
RWL: This is where Ken can provide useful expertise.

>The chimney and its adapters are loose fitting and
>very light, made of tin cans, held in place by
>gravity. I do use gloves when I lift it off.
>Sometimes I use a 3 ft. heat pipe chimney on the stump
>stove that weighs less than three pounds, including
>two size adaptors. Easily removable to check the
>food. Chimney height can be made adjustable to fit
>the needs for draft to control the fire.
>
RWL: Again several important ideas here. I am concerned about the need
for gloves (which I use all the time with test stoves - but think we should
find a way to avoid). Lanny Henson's stove chimney design might be a good
way to go. This requires a good match between the pot and the stove - but
this is also something we should strive to achieve as well.
At the Aprovecho meeting, we used a "capture pipe" like yours (but it was
limited to capturing the exhaust steam - so as to not have the steam release
influence the CO measurements). It was possible to use, but I think most
cooks in developing countries would find was to avoid its use.
I think we need to start recommending the greater use of the multiple small
tin cans for low cost stove chimneys. I'd like to hear if anyone has had
success in disseminating this approach.
We need to continue this part of the discussion a lot. I think we may have
problems coupling the metal and ceramic technologies here.

>As with the old "ten can" stove, the char can be
>burned or recovered after it has cooled by being
>denied combustion air or quenched with water. I do
>not show scale in the drawing. Visualize it with a
>gallon-sized or smaller pot. All parts, including
>some not shown, can be assembled in various geometries
>that permit roasting, baking, boiling, frying, etc.

(RWL): Again - lots to talk about here. On burning the charcoal after
production - I have not seen this to be successful (as the combustion is
taking place at the bottom of the assembly - too far from the cook pot). I
worry about the thermal shock in quenching with water in a ceramic unit. We
still have a lot to learn about this aspect of the charcoal-making stove.

>I have just seen photos from Aprovecho and recognized
>your hour-glass ceramic stove. I wish I could see
>more. Would like to help you in any way I can.
>
>I work very slowly, and so it will be some time before
>I can test the ideas shown in the drawing. I am
>presently much engaged with formulating strong,
>insulative clay mixes. I will send samples, but first
>I must have your "snail mail" address. Hoping that
>this finds you well and rested from your trip.
>
RWL: You may think you are working slowly - but you are doing more than
anyone else in this area. Thanks for that. We both have a lot to learn
from Ken Goyer and others at Aprovecho on insulative bricks. I was much
impressed by one Dean Still showed me made with just charcoal (85%) clay -
as almost everyone has both these ingredients. I am afraid that it will be
hard to also make it non-shrinking, but it looked adequately strong and was
very light. Make sure you look at the good article on this subject by Dale
Andreatta at Tom Mile's site. Sine you are so skilled with both metal work
and clay, I hope you will not
My snailmail address is 21547 Mountsfield, Golden, CO 80401. Thanks for
the salutation and I hope all is well with you also.

Ron

>Sincerely,
>
>Dick Boyt
>
>
>__________________________________
>Do you Yahoo!?
>SBC Yahoo! DSL - Now only $29.95 per month!
>http://sbc.yahoo.com
>
>

From tmiles at TRMILES.COM Wed Jun 18 10:42:31 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:25 2004
Subject: Stove Testing Seminar Summary and Results
Message-ID: <WED.18.JUN.2003.074231.0700.TMILES@TRMILES.COM>

I have posted Dean's Summary and Results of the Stove Testing Seminar in pdf format on the Stoves web pages.

Tom Miles

From ronallarson at QWEST.NET Wed Jun 18 11:04:43 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: [ethos] [Fwd: stove photos]
In-Reply-To: <002a01c33542$dd839e50$6501a8c0@OFFICE3>
Message-ID: <WED.18.JUN.2003.090443.0600.RONALLARSON@QWEST.NET>

Tom, Lisa, Stuart, Ethos, stoves:

1. Re photographs - I also appreciate these. Great additions to Tom's
files. One question I have is on the height of the cooking and wood-entry
surfaces. Any standards developing (as in the US- where all are same, I
think, at? It is nice to be able

It looks pretty likely that I will take a trip to Peru in late July-early
August. Anyone able to supply any stoves contacts there?

I'm especially hoping that Lisa can make some contacts at her meeting in
Mexico that I can follow up with.

Ron

>-----Original Message-----
>From: owner-ethos@vrac.iastate.edu
>[mailto:owner-ethos@vrac.iastate.edu]On Behalf Of Tom Miles
>Sent: Tuesday, June 17, 2003 8:39 PM
>To: Stuart Conway; ethos; Lisa Buttner
>Subject: Re: [ethos] [Fwd: stove photos]
>
>
>Stuart,
>
>I'm sure there are many stories behind each of the pictures and the 5800
>stoves tat you mentioned. (Does that include Pat Manley's 1000 stoves?)
>
>I don't have time to put the pictures and their stories up on the Cocinas y
>Estufas Mejoradas website
>http://www.repp.org/discussiongroups/resources/estufas/ before the Mexico
>conference but I look forward to seeing the stories in Spanish so that we
>can include them along with the reports of the stove performance from your
>surveys.
>
>I also hope that Lisa will direct people to the Cocinas y Estufas site and
>to the bioenergia and stoves email lists so that we can generate some
>discussion to help support dissemination in Mexico, Central and South
>America.
>
>Saludos,
>
>Tom
>
>----- Original Message -----
>From: "Stuart Conway" <stuart@treeswaterpeople.org>
>To: "ethos" <ethos@vrac.iastate.edu>; "Lisa Buttner" <LButtner@winrock.org>
>Sent: Tuesday, June 17, 2003 4:56 PM
>Subject: [ethos] [Fwd: stove photos]
>
>
>> Lisa,
>>
>> Here are some more photos for the conference in Mexico, including some
>> that Jeremy Foster took in Michoacan. Larry Winiarski and Jeremy built
>> some Justa stoves to demonstrate them for GIRA.
>>
>> Stuart
>>
>
>
>
>

From ronallarson at QWEST.NET Thu Jun 19 08:36:39 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: Gasification for biomass briquettes
In-Reply-To: <000901c33683$4a0bd150$523029c4@biomassenergy>
Message-ID: <THU.19.JUN.2003.063639.0600.RONALLARSON@QWEST.NET>

Peter (cc AD and Stoves):

I am taking the liberty of sending your request for information on
efficiently using the pyrolysis gases from your charcoal briquette making
operation on to our full "stoves" list. This is to ask all "stovers" to
assist as this is a most important question.

There are a number of people on the list who are using gasifiers for
producing gases for engines and/or stoves. There are also others developing
pyrolysis units - attempting to get charcoal. My own interest is in using
small cookstoves to produce charcoal as a co-product. I feel this is at a
stage where persons like yourself need to see if this could be profitable -
you supply the fuel in a suitable biomass form (pillows or cylinders, etc)
and the stove user returns charcoal to you for your processing into a final
product. There is plenty of material on this type of charcoal-making stove
in the early archives of "stoves" - but no commercial activity yet. More
development is needed. We have also talked about using the pyrolysis gases
for larger commercial operations like bakeries, pottery kilns, cement
making, or any place where biomass is being consumed for large thermal
operations. In all of these, I believe charcoal can be a useful and
income-generating sideline. So far, I am not aware of anyone doing this -
the pyrolysis gases are usually exhausted - and as you point out - should
not be. Here is hoping you will have generated the interest of some
manufacturer of gasifiers to instead produce a charcoal maker. I just did
a google search on "India gasifier manufacturers" and found many lists.
Perhaps Dr. Karve or others in India can tell who has a unit that might
emphasize charcoal rather than gases.

Several more answers below.
-----Original Message-----
From: Peter [mailto:peter.gathercole@raha.com]
Sent: Thursday, June 19, 2003 10:53 AM
To: ronallarson@qwest.net
Cc: adkarve@PN2.VSNL.NET.IN
Subject: Gasification for biomass briquettes

Dear Ron/Mr Karve/Paul,

I am Peter Gathercole of Biomass Energy Tanzania Limited and we are
developing the biomass briquetting market in Tanzania. I have been in
contact with NEWDAWN and Crispin who has kindly send me your contact details
for advise on the questions I raised below. Would it be possible to obtain
some imfo from you guys on a way ahead for us to encourage the use of the
product by removing the volatiles efficiently and usefully, which then
enable the briquettes to be more user friendly than without carbonisation.
We are looking at many issues relating to improved stoves (NEWDAWN) and
locally made insulated units with increase secondary air ways to improve
combustion and use up the gases rather than waste them.

 

If you can assist I would be highly appreciative.

 

Please find questions I raised to Crispin:

 

Dear Crispin,

We are looking at extracting the volatiles from our biomass briquettes on
a commercial basis to improve the saleability of the briquette product and
also to harness the gas from the wood waste. Do you have any base date on
wood fuel gas constituents or composition of the gases, on a variety of
biomass woody wastes.

 

(RWL): I do not have much other than that there will be a tremendous
array of constituents - and of course many pyrolyzers are attempting to
condense and capture various liquids. The gases are primarily methane, CO
and hydrogen. Your main concern will be that the effluent gases not contain
too much moisture vapor - so that fairly dry biomass must be the starting
point. Otherwise, the gases will not be ignitable. here is hoping that
people like Dr. Michael Antal or Dr. Tom reed can answer your question with
full literature citations. There is plenty of scientific literature on this
subject.

 

Also any data on gasifiers which could be used on small scale to produce
such gas and leave a carbonised briquette which could then be sold. We are
looking at a more efficient way of empowering the current charcoal producers
to continue with briquettes and harness the energy within their communities
to produce alternative charcoal, cook at the same time on the gas extracted.
(communal cooking and making charcoal).

 

(RWL): I would urge you not to use the word "gasifier" to describe
what you are doing - I prefer "pyrolyzer." I find that the people expert in
"gasifiers" are interested in minimizing the production of charcoal.

 

Best of luck.

Ron

 

BRs

 

 

Peter Gathercole

Development Director

Biomass Energy Tanzania Limited

PO Box 31748, Dar Es Salaam, Tanzania

Tel/Fax: +255 22 2666667 Cell:+ 255 (0)744 785340

The data contained within this email and any accompanying or attached file
is legally privileged. The information is intended only for the use of the
individual or entity for whom it was intended. If you are not the intended
recipient, you are hereby notified that any disclosure, copying, storing,
distribution or taking of any action in reliance on the contents of this
email is strictly prohibited. If you have received this email in error, you
please notify us immediately by telephone, fax or return email and
thereafter delete the transmission you have received. We shall be pleased to
reimburse any reasonable costs incurred.

From ronallarson at QWEST.NET Thu Jun 19 09:46:32 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: Thoughts - Prototype clay biomass-pyrolyzing stove
In-Reply-To: <200306110811.h5B8BU017258@ns1.repp.org>
Message-ID: <THU.19.JUN.2003.074632.0600.RONALLARSON@QWEST.NET>

Kobus (cc Richard, Stoves)

On June 11 you said (with my inserts)
>
>Ron and Richard (and stovers),
>
>Any progress with your clay type pyrolyzing stove? I think it is a very =
>good idea, has any other stovers tried doing that?
>
(RWL): Some progress reported back by me to "stoves" on June 8. But I
really only said that my ceramic versions were not yet successful. I think
I was not adequately accounting for the extra thickness with ceramics over
my experience with metal stoves - as applies to air hole sizes, etc.

>Chimney
>If it is clean burning like this new technology allows, does it need a =
>fixed chimney? Small stoves are preferred for their portability. The =
>way I understand it, the higher the chimney (or internal chimney) the =
>higher the resultant draft, so for start-up that is OK until you have to =
>turn it down for pot simmering. Controlling primary air can attempt to =
>reduce the draft and therefore the emission temps at the exit point. It =
>is not advisable to alter the airflow to achieve lower exit temperatures =
>in a pyrolyser or gasifier as it will affect the required A/F ratios. =
>One would have to constantly adjust the primary air to counteract high =
>draft created by the fixed chimney. I do not see a primary air control =
>in your prototype though. I suppose that is generally why an internal =
>chimney is preferred, it gives you a high natural draft (by selecting a =
>higher chamber) without having to apply chimneys to it.

(RWL): I have never attached a large chimney to any of my charcoal-making
stoves - but if I did, I don't believe it would be like the recent Boyt
design. But I do think that one can still control output power (related to
temperature) with primary air control - even with the higher draft with a
chimney. In my experiments, I have found a plug to be the easiest way to
control primary air. I have not found it necessary to control secondary
air - but I do think my "Aprovecho" experiments were with too much secondary
air.
You say above " Controlling primary air can attempt to reduce the draft and
therefore the emission temps at the exit point." I would not state the
problem that way - rather controlling primary air controls the amount of
pyrolysis gases produced and when combusted, the output power and
temperatures are controlled by the greater production of hot gases. So
controlling primary air is a very useful feature of such a stove - and not
one generally available to the usual stove. In Tom Reed's or the Z-stove
forced air designs, the fan speed serves a similar function. I don't think
I quite understand your last sentence - but certainly the pyrolysis stove
would not work without a small enclosed combustion region (which serves some
"chimney " functions - perhaps what you are calling an internal chimney.
The taller this chimney the more likely to achieve complete combustion and
less soot on the pot and less quenching and noxious emissions. But this
also leads to greater expense and thermal losses. I have found that a
height that is 150 % to 200 % of the diameter is acceptable - but this needs
a lot more work.
>
>If you then dump the external chimney the internal chimney below the pot =
>will give you the required draft in any case. Tom R mentioned "it is =
>also useful to limit the flow of gases upward with a bluff body so that =
>you get a ring of heat and better draft. The gases from that area of =
>charcoal (biomass) can't fill the upper chamber, and so result in =
>instability as some gases rise and others fall."

RWL: I agree with your first sentence of course - but not sure of rest. I
don't believe that a "bluff body" is going to improve draft. I have tried
something similar as a means of reducing the distance needed for the
secondary air to diffuse to the pyrolysis gases. In most of Tom's recent
work, his use of forced air allows a very short combustion region - almost
no "chimney". In most cases, I think we can narrow the combustion region
(perhaps by internal insulation) - but I think I would be able to observe
downward flowing cold air and don't think that has been occurring. The
"bluff body" should be helpful in maintaining ignition.
>
>Your pot will act as a bluff body, the areas along the side of the pot =
>will aid the draft (and obviously heat transfer), plus at the top where =
>you show the chimney, you could rather utilize this heat by placing a =
>pot on top (two pot stove?). If others disagree I would like to hear =
>about i.e. reasons why it won't work or hard to achieve. I am working =
>on a similar type stove with an oven below and a hob above it, running =
>on charcoal. =20

RWL: The pot has always seemed to me to be a "quencher" - if the flames
are reaching it. Then we get unburned gases and harmful emissions. (This
one of the reasons that I think we should be investigating "swirl" so as to
get a longer flame path length but without adding height). But I like your
other arguments (added chimney height from a "shield" - (Aprovecho is
calling this a "Baldwin" shield (also called convective) - and the two pot
idea.
I would like very much to hear about the oven and "hob" (whose definition I
don't know).
>
>Secondary air
>If you have your secondary air drawn in from the top near the hob, =
>chances are that it will be pre-heated and contain emission gases with =
>some PIC which is directed back for complete burning. I am encouraged =
>by this method in my trials and think it will make a difference to =
>cleaning up emissions in chimney-less stoves. =20
>=20

RWL: I still don't have enough experience yet to comment on the
pre-heating. I am dubious of trying to bring back any PICs (Products of
Incomplete Combustion)- as they could prevent adequate O2. Please tell us
more on your experiments.

>Does it pyrolyze biomass yet? I would like to see photos of your =
>current prototype.

(RWL): No problem in bioass pyrolysis with metal units - many hundreds of
successful test reported in the early stoves archives. But not any I am
aware of with a totally ceramic unit. No current ceramic prototype worth
sending out a photograph on. But this is not to say there should be an
insurmountable problem - just need more work, I hope.

>
>Regards
>
>Kobus
>
>

From ventfory at IAFRICA.COM Thu Jun 19 09:54:06 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:25 2004
Subject: New activated carbon-from-wood plant
Message-ID: <THU.19.JUN.2003.155406.0200.VENTFORY@IAFRICA.COM>

Construction of a 10,9 Million USD carbon-from-wood plant has begun in Estcourt, in western KwaZulu Natal, South Africa. It is scheduled to start production in January 2004, managed by Karbotek, an Italian/South African partnership. It is a spin off to the 6,4 Billion USD strategic arms deal for the South African Defence Force.

For more information goto:
http://free.financialmail.co.za/03/0516/business/bbus.htm
>>>
Kobus

From kchisholm at CA.INTER.NET Thu Jun 19 10:40:39 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:25 2004
Subject: Gasification for biomass briquettes
Message-ID: <THU.19.JUN.2003.114039.0300.KCHISHOLM@CA.INTER.NET>

----- Original Message -----
From: "Ron Larson" <ronallarson@QWEST.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, June 19, 2003 9:36 AM
Subject: Re: [STOVES] Gasification for biomass briquettes

> (RWL): I do not have much other than that there will be a
tremendous
> array of constituents - and of course many pyrolyzers are attempting to
> condense and capture various liquids. The gases are primarily methane, CO
> and hydrogen. Your main concern will be that the effluent gases not
contain
> too much moisture vapor - so that fairly dry biomass must be the starting
> point. Otherwise, the gases will not be ignitable.

What is your general impression on a good range of moisture contents of feed
biomass for easy gasification operation, yielding a gas which is readily
combustible? For example, "too much" moisture" may yield a gas which is
difficult to ignite, and "too little moisture" may yield too much tar and
volatile loss.

>
> Also any data on gasifiers which could be used on small scale to
produce
> such gas and leave a carbonised briquette which could then be sold. We are
> looking at a more efficient way of empowering the current charcoal
producers
> to continue with briquettes and harness the energy within their
communities
> to produce alternative charcoal, cook at the same time on the gas
extracted.
> (communal cooking and making charcoal).

Note that there may be a different "optimum moisture range for:
1: A case where it is desired to maximize the production of clean
combustible gas.
and
2: A case where it is desired to "degass the briquettes" in a way that
charcoal yield is maximized, while still producing combustible "off gas."
>
>
>
> (RWL): I would urge you not to use the word "gasifier" to describe
> what you are doing - I prefer "pyrolyzer." I find that the people expert
in
> "gasifiers" are interested in minimizing the production of charcoal.
>
Good point indeed!! :-)

Kindest regards,

Kevin

From tmiles at TRMILES.COM Thu Jun 19 11:10:55 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:25 2004
Subject: PROLENA honoured in Ashden Awards 2003
Message-ID: <THU.19.JUN.2003.081055.0700.TMILES@TRMILES.COM>

Following is Grant's report on t he Ashden Awards 2003.

Congratulations Prolena.

Thanks to Grant and to Ron Larson for making Stovers aware of the award.

Tom Miles

----- Original Message -----
From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
Sent: Thursday, June 19, 2003 7:07 AM
Subject: [hedon] HEDON member PROLENA honoured in Ashden Awards 2003

> The award ceremony for the 2003 Ashden Awards was held on 18 June 2003
> in London. A total of 6 finalists from developing countries under the
> categories of 'Food Security', 'Enterprise' and 'Community Welfare'
> were recognised for their outstanding and innovative renewable energy
> projects.
>
> For full details see http://www.hedon.info/news.php?op=view&rowid=62
>
> Congratulations to Rog?rio Carneiro de Miranda, representing the NGO
> PROLE?A in Nicaragua, an active HEDON member, who was awarded the
> runner-up prize in the 'Food security' category. The PROLE?A project
> works to produce and promoting fuel-efficient stoves for small
> household tortilla businesses.
>
> The winner in the food security category was the Energy and Research
> Training Centre in Eritrea. The centre works with local women to
> produce and distribute smokeless, fuel efficient clay stoves which
> reduce firewood collection time whilst creating cleaner, healthier
> living and working environments. The Award will be used to train 900
> women to make stoves, each of whom will train a further 10 women in
> their village to do the same.
>
> Details of the other award winners, and links to the Ashden Awards
> webpage may be found on the HEDON Household Energy Network webpage at:
>
> http://www.hedon.info/news.php?op=view&rowid=62
>
> The HEDON Household Energy Network was instrumental in bringing the
> awards to the attention of a large number of those that applied and
> for assisting a number of small organisations in developing countries
> to make their applications.
>
> --
> Grant Ballard-Tremeer PhD, visit Eco on the web at http://ecoharmony.com
> HEDON Household Energy Network http://hedon.info
> SPARKNET Knowledge Network in Southern and East Africa
http://sparknet.info
> -------------------

From psanders at ILSTU.EDU Thu Jun 19 13:07:54 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:25 2004
Subject: Gasification for biomass briquettes
In-Reply-To: <NGBBKDEHILILFNJPHEFIOEAFCPAA.ronallarson@qwest.net>
Message-ID: <THU.19.JUN.2003.120754.0500.PSANDERS@ILSTU.EDU>

Peter (and Ron and all),

Please include me in any discussion on biomass briquettes and their
gasification.

Seems that Peter is not on the Stoves List Serve, and maybe this topic
should (eventually, but not immediately) have a separate (side) discussion
once we have identified the people who want to do this discussion. (Then
we can send periodic up-dates to the whole Stoves list.)

So others should express their interest to be sure that they join with
"Peter, Paul and Ron." Should include Richard Stanley and others. We
need to compile a list (not a list-serve) so that everyone gets copies of
the messages.

In Mozambique, with my co-worker Apolinario Malawene, we are making biomass
briquettes for burning in small gasifiers. Our materials for the
briquettes are like Richard Stanley's (he got us started with this), but
with diameters of about 5 or 6 cm, and no holes in the center. We are not
far enough along to say if we want to save the charcoal or want to try to
burn it in location in the stoves.

Peter, how dense are your briquettes? The compaction of ours is low, and
after gasification they are very weak and would not hold up well to
handling and transport.

But I know that gasifier (pyrolyzed) corn cobs are great little
"briquettes" that can be transported as charcoal.

Paul
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From ronallarson at QWEST.NET Thu Jun 19 13:22:46 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: PROLENA honoured in Ashden Awards 2003
In-Reply-To: <200306191423.h5JEN7G16545@ns1.repp.org>
Message-ID: <THU.19.JUN.2003.112246.0600.RONALLARSON@QWEST.NET>

Tom, Grant, and other stovers:

I do not know the full story of this award to the Ashden-award winning
Eritrean group but hope that someone will congratulate them and invite them
to report to "stoves" on their work. (I haven't been able to locate a good
web site for the stoves work.)
This message is especially directed to Robert van Buskirk (see
http://www.punchdown.org/rvb/mogogo/index.html) I have no way of knowing
how much help Robert provided to the Eritreans - but I am especially
impressed by the high technical quality of what I see at Robert's
"Punchdown" site. I congratulate him too for all his efforts there, even if
the Ashden award is not for that assistance.

Ron

 

>-----Original Message-----
>From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>Behalf Of Tom Miles
>Sent: Thursday, June 19, 2003 9:11 AM
>To: STOVES@LISTSERV.REPP.ORG
>Subject: PROLENA honoured in Ashden Awards 2003
>
>
>---------------------- Information from the mail header
>-----------------------
>Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
>Poster: Tom Miles <tmiles@TRMILES.COM>
>Subject: PROLENA honoured in Ashden Awards 2003
>-------------------------------------------------------------------
>------------
>
>Following is Grant's report on t he Ashden Awards 2003.
>
>Congratulations Prolena.
>
>Thanks to Grant and to Ron Larson for making Stovers aware of the award.
>
>Tom Miles
>
>----- Original Message -----
>From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
>Sent: Thursday, June 19, 2003 7:07 AM
>Subject: [hedon] HEDON member PROLENA honoured in Ashden Awards 2003
>
>
>> The award ceremony for the 2003 Ashden Awards was held on 18 June 2003
>> in London. A total of 6 finalists from developing countries under the
>> categories of 'Food Security', 'Enterprise' and 'Community Welfare'
>> were recognised for their outstanding and innovative renewable energy
>> projects.
>>
>> For full details see http://www.hedon.info/news.php?op=view&rowid=62
>>
>> Congratulations to Rog?rio Carneiro de Miranda, representing the NGO
>> PROLE?A in Nicaragua, an active HEDON member, who was awarded the
>> runner-up prize in the 'Food security' category. The PROLE?A project
>> works to produce and promoting fuel-efficient stoves for small
>> household tortilla businesses.
>>
>> The winner in the food security category was the Energy and Research
>> Training Centre in Eritrea. The centre works with local women to
>> produce and distribute smokeless, fuel efficient clay stoves which
>> reduce firewood collection time whilst creating cleaner, healthier
>> living and working environments. The Award will be used to train 900
>> women to make stoves, each of whom will train a further 10 women in
>> their village to do the same.
>>
>> Details of the other award winners, and links to the Ashden Awards
>> webpage may be found on the HEDON Household Energy Network webpage at:
>>
>> http://www.hedon.info/news.php?op=view&rowid=62
>>
>> The HEDON Household Energy Network was instrumental in bringing the
>> awards to the attention of a large number of those that applied and
>> for assisting a number of small organisations in developing countries
>> to make their applications.
>>
>> --
>> Grant Ballard-Tremeer PhD, visit Eco on the web at http://ecoharmony.com
>> HEDON Household Energy Network http://hedon.info
>> SPARKNET Knowledge Network in Southern and East Africa
>http://sparknet.info
>> -------------------
>
>

From ronallarson at QWEST.NET Thu Jun 19 16:15:05 2003
From: ronallarson at QWEST.NET (Ron Larson)
Date: Tue Aug 10 18:30:25 2004
Subject: Eritrea Stoves Project Update
In-Reply-To: <3EF2013D.A42A4D54@lbl.gov>
Message-ID: <THU.19.JUN.2003.141505.0600.RONALLARSON@QWEST.NET>

Robert (cc stoves)

Thanks for the update.

I am impressed that you were able to get the carbon credits . No time to understand your report for another 10 days away - but perhaps you could tell "stoves" some of the steps that one has to take for others to replicate your success. You have probably said how much this is worth per stove - but I haven't had time to read yet (but have sent on to Tom Mills to see if the 47 pages are too much - maybe send to another site if so??).

I am still very impressed!

Ron

>-----Original Message-----
>From: Robert Van Buskirk [mailto:rdvanbuskirk@lbl.gov]
>Sent: Thursday, June 19, 2003 12:30 PM
>To: Ron Larson
>Cc: Tom Miles; STOVES@LISTSERV.REPP.ORG; robert@punchdown.org
>Subject: Eritrea Stoves Project Update
>
>
>
>Dear Ron:
>
>Just to give you a brief update on the Eritrea stoves project.
>
>We made two visits, one in January and one in March, and completed
>the work on developing the carbon credit calculation methodologies.
>In March we completed the verification of the carbon credits which
>is documented in the report:
>
>http://www.punchdown.org/rvb/mogogo/EDISPVerifyDoc200303.html
>
>This document also has links to spreadsheets with the complete
>village interview data from about 17 villages which was primarily
>collected with the hard work of the Energy Research and Training
>Center in Eritrea staff.
>
>Regarding the Ashden award, I am glad to hear that the Eritreans
>won this year. I simply provided information and data for the
>Ashden committee from our continuing evaluation, and technical
>analysis work of the project analysis. I think that the award
>will be a substantial boost to the Eritrean efforts. Currently
>they are installing stoves at the rate of about 3,000/year and
>they need to grow the installation rate to about 25,000/year
>if they are going to replicate the success of the Chinese
>national stove program. Training 900 stove construction artisans
>will help create the increased grassroots demand pull for this
>growth.
>
>The challenges for program growth also exist on the supply side.
>This is because in order to make the stoves affordable, about
>$10 worth of materials need to be provided by the government.
>Some of this may be paid for by carbon credits. The Eritreans
>have sold some carbon credits from the program (including the
>4000 tonnes verified in the above report). The carbon credits
>are being bought at the retail end by a law firm, Baker McKenzie
>which is using them to offset its carbon emissions impacts in
>order to become carbon neutral. From the Future Forests web
>site (http://www.futureforests.com/press/supportandoffers.asp):
>
>"Baker McKenzie
>This leading global law firm has increased its commitment to
>sustainability by making all of its London offices Carbon Neutral
>in 2002, following a switch in energy use to renewable sources.
>Over half a million people over the next seven years will benefit
>from Baker & McKenzies investment into energy efficient stoves
>in Eritrea, cutting CO2 emissions"
>
>We also had a graduate student, Ayca Ergeneman from the Goldman
>School of Public Policy who did a comparative analysis of Indian,
>Chinese, Ethiopian, and Eritrean rural stove programs. I will send
>a draft of this report to Ron. We will probably make some fairly
>minor modifications and then publish this as a Lawrence
>Berkeley National Laboratory report.
>
>So I think that the conceptual plan is to grow the capacity and
>resources of the Eritrea stove program by 25% to 100% per year
>to get installation rates up to 25,000 stoves per year within
>3-5 years, and then sustain a minimum 25,000 stove/year installation
>rate for at least 10 years to transform most households to the
>improved stoves. Or if we are lucky perhaps installation rates
>can increase to 50,000 to 100,000 per year, in which case it will
>be possible to cover the whole country in less than 10 years.
>
>If the installation rate is 4,000 to 8,000 stoves in this year,
>then the Eritrea program will be more or less on schedule. I
>will visit Eritrea again at the end of 2003, and probably
>produce another carbon credit verification report with updated
>data.
>
>Sincerely,
>
>Robert Van Buskirk
>volunteer
>Eritrea Technical Exchange and
>Scientist,
>Lawrence Berkeley National Laboratory
>
>
>Ron Larson wrote:
>>
>> Tom, Grant, and other stovers:
>>
>> I do not know the full story of this award to the
>Ashden-award winning
>> Eritrean group but hope that someone will congratulate them and
>invite them
>> to report to "stoves" on their work. (I haven't been able to
>locate a good
>> web site for the stoves work.)
>> This message is especially directed to Robert van Buskirk (see
>> http://www.punchdown.org/rvb/mogogo/index.html) I have no way of knowing
>> how much help Robert provided to the Eritreans - but I am especially
>> impressed by the high technical quality of what I see at Robert's
>> "Punchdown" site. I congratulate him too for all his efforts
>there, even if
>> the Ashden award is not for that assistance.
>>
>> Ron
>>
>> >-----Original Message-----
>> >From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On
>> >Behalf Of Tom Miles
>> >Sent: Thursday, June 19, 2003 9:11 AM
>> >To: STOVES@LISTSERV.REPP.ORG
>> >Subject: PROLENA honoured in Ashden Awards 2003
>> >
>> >
>> >---------------------- Information from the mail header
>> >-----------------------
>> >Sender: The Stoves Discussion List <STOVES@LISTSERV.REPP.ORG>
>> >Poster: Tom Miles <tmiles@TRMILES.COM>
>> >Subject: PROLENA honoured in Ashden Awards 2003
>> >-------------------------------------------------------------------
>> >------------
>> >
>> >Following is Grant's report on t he Ashden Awards 2003.
>> >
>> >Congratulations Prolena.
>> >
>> >Thanks to Grant and to Ron Larson for making Stovers aware of the award.
>> >
>> >Tom Miles
>> >
>> >----- Original Message -----
>> >From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
>> >Sent: Thursday, June 19, 2003 7:07 AM
>> >Subject: [hedon] HEDON member PROLENA honoured in Ashden Awards 2003
>> >
>> >
>> >> The award ceremony for the 2003 Ashden Awards was held on 18 June 2003
>> >> in London. A total of 6 finalists from developing countries under the
>> >> categories of 'Food Security', 'Enterprise' and 'Community Welfare'
>> >> were recognised for their outstanding and innovative renewable energy
>> >> projects.
>> >>
>> >> For full details see http://www.hedon.info/news.php?op=view&rowid=62
>> >>
>> >> Congratulations to Rogrio Carneiro de Miranda, representing the NGO
>> >> PROLE A in Nicaragua, an active HEDON member, who was awarded the
>> >> runner-up prize in the 'Food security' category. The PROLEA project
>> >> works to produce and promoting fuel-efficient stoves for small
>> >> household tortilla businesses.
>> >>
>> >> The winner in the food security category was the Energy and Research
>> >> Training Centre in Eritrea. The centre works with local women to
>> >> produce and distribute smokeless, fuel efficient clay stoves which
>> >> reduce firewood collection time whilst creating cleaner, healthier
>> >> living and working environments. The Award will be used to train 900
>> >> women to make stoves, each of whom will train a further 10 women in
>> >> their village to do the same.
>> >>
>> >> Details of the other award winners, and links to the Ashden Awards
>> >> webpage may be found on the HEDON Household Energy Network webpage at:
>> >>
>> >> http://www.hedon.info/news.php?op=view&rowid=62
>> >>
>> >> The HEDON Household Energy Network was instrumental in bringing the
>> >> awards to the attention of a large number of those that applied and
>> >> for assisting a number of small organisations in developing countries
>> >> to make their applications.
>> >>
>> >> --
>> >> Grant Ballard-Tremeer PhD, visit Eco on the web at
http://ecoharmony.com
> >> HEDON Household Energy Network http://hedon.info
> >> SPARKNET Knowledge Network in Southern and East Africa
> >http://sparknet.info
> >> -------------------
> >
> >

From tmiles at TRMILES.COM Thu Jun 19 20:28:15 2003
From: tmiles at TRMILES.COM (Tom Miles)
Date: Tue Aug 10 18:30:25 2004
Subject: Eritrea Dissemination of Improved Stoves Program
Message-ID: <THU.19.JUN.2003.172815.0700.TMILES@TRMILES.COM>

The report "DISSEMINATION OF IMPROVED COOKSTOVES IN RURAL AREAS OF THE
DEVELOPING WORLD: Recommendations for the Eritrea Dissemination of Improved
Stoves Program", Spring 2003, by Ay?a Ergeneman for Eritrea Energy Research
and Training Center (ERTC), can be found on the biomass cooking stoves
website in HTML and pdf (1 MB) format.

Many thanks to Robert Van Buskirk for providing this report and
congratulations to the ERTC for the Ashden Award in Food Security.

Tom Miles
Ron Larson

http://www.repp.org/discussiongroups/resources/stoves/Vanbuskirk/EriStoveAPA
Report.htm

From ventfory at IAFRICA.COM Fri Jun 20 04:38:44 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:25 2004
Subject: Fw: [ethos] [Fwd: stove photos] Briquette gasification
Message-ID: <FRI.20.JUN.2003.103844.0200.VENTFORY@IAFRICA.COM>

Ron, Richard S and stovers
Ron said

>I guess I still have not heard of anyone "gasifying" or pyrolyzing your "non-biomass" >briquettes - only combusting. I hope Kobus can clarify if he has been doing this.

Yes Ron I am trying to help Richard Stanley build a non-woody biomass briquette stove on gasification principles. I am still awaiting arrival of briquettes. Richard has been kind enough to send me the manual for building and using his briquette making press in exchange for me building him the stove. The manual is for sale, but the improved press manual will only be ready in a couple of weeks for those who are interested in buying it.

I am using "riser" material which is easy to cut or for drilling holes. No progress yet, but be sure that I will have some ongoing questions to the list as I try to help my "neighbour" in Kampala, Uganda.

Richard S said: He has (in response to an earlier concern of yours, I think) various formulae for calculating chamber size based on calorific value of the fuel and size/shape /weight of fuel load used.

I am using formulas made available by Piet Visser of BTG ( www.cookstove,net ) on the Crest page.

They yield similar results to Ron's suggestion of making the comb. chamber height 150 - 200% of the combustion chamber diameter.

Regards

Kobus

ventfory@iafrica.com

From ventfory at IAFRICA.COM Fri Jun 20 04:25:02 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:25 2004
Subject: Fw: Thoughts - Prototype clay biomass-pyrolyzing stove
Message-ID: <FRI.20.JUN.2003.102502.0200.VENTFORY@IAFRICA.COM>

Ron,

Referring to email sent to list on 19th June

Ron, I value your comments on my observations of the clay type pyrolysers.

Instead of me saying ...it is not advisable to alter airflow to achieve lower exit temperatures (huhh?)... I should have said...it is not advisable to alter the airflow to turn down the power...as it will interfere with the A/F ratios required for gasification/pyrolysis.

Thank you for explaining that primary air controls the amount of pyrolysis gases produced...and the output power...are controlled by the greater production of hot gases...

My usage of oven and hob relates to a new design for the upmarket buyer, unless I can streamline the eventual production process. The oven is basically a aluminium pot with an oven stand inside. The "oven pot" is removed only during start-up and to place or remove food inside (i.e whole chicken or cakes et). It has a non-adjustable insulated sleeve to enhance convection to the outside of the standard pot, but instead of having the flue gases exit straight up they first hit a stove top and exit horizontally trough specially sized and strategically placed holes. The cross-sectional area of the exit point of the comb. chamber is maintained throughout the oven, i.e. around the oven pot and exit holes underneath the top stovetop plate. The "hob" refers to an accessory similar to a LP gas type accessory for placing pots or pans on. Instead of such an accessory a simple hole at the top of the oven assembly brings the hot emission gases in contact with a second pot of any shape and size. No prototype yet.

I said:
>If you have your secondary air drawn in from the top near the hob, =
>chances are that it will be pre-heated and contain emission gases with =
>some PIC which is directed back for complete burning. I am encouraged =
>by this method in my trials and think it will make a difference to =
>cleaning up emissions in chimney-less stoves.

You said: RWL: I still don't have enough experience yet to comment on the
pre-heating. I am dubious of trying to bring back any PICs (Products of
Incomplete Combustion)- as they could prevent adequate O2. Please tell us
more on your experiments.

All I've tried was merely drawing mostly O2 from the top of the stove near the exit point of the combustion chamber via a metal cylinder/sleeve back down in line with where I indicated my two 3/4 inch holes on my stove page. Just a note to Tom and Crispin that I have now drilled 22 holes (10mm thick, 40mm apart) 100 mm down from the top of the chamber and at an upward angle (45?) and filled up the two 3/4 inch holes with high temperature tolerant concrete, seems to bond well with "risers".

The amounts of PIC drawn back down with the O2 is not known, but through trial and error a nice balance can be obtained. Will keep you informed on prototype development.

Regards

Kobus

From ventfory at IAFRICA.COM Fri Jun 20 04:58:51 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:25 2004
Subject: Fw: [STOVES] New activated carbon-from-wood plant
Message-ID: <FRI.20.JUN.2003.105851.0200.VENTFORY@IAFRICA.COM>

Dear Kevin

Thanks for the interest, unfortunately I do not have much information, but
we are investigating this and will let you and the list know. The plant
will utilize the renewable resources in KwaZulu Natal from properly
maintained FSC certified plantations, mostly Eucalyptus hardwood spp from
Australasia and not the waste (maybe some waste). The FSC accreditation is
required by the plantations wishing to supply the plant, as specified by the
overseas buyers of the carbon. The plant will compete with the paper pulp
mills located along the East coast of KwaZulu Natal, which will hopefully
dramatically increase the current price paid for Eucalyptus spp by these
paper mills. As mentioned in the link to the report a substantial saving is
realised by the growers (Mill delivered price), by not having to transport
timber so far away anymore.

Will keep you posted.

Regards

Kobus

----- Original Message -----
From: Kevin Chisholm <kchisholm@ca.inter.net>
To: Kobus <ventfory@IAFRICA.COM>
Sent: Thursday, June 19, 2003 4:50 PM
Subject: Re: [STOVES] New activated carbon-from-wood plant

> Dear Kobus
>
> I am very interested in the Karbotek concept for utilizing waste biomass
for
> charcoal production here in Nova Scotia.
>
> Are there any particular wood requirements that make the process
> particularly advantageous for South Africa? (Typical wood waste here would
> be from White Spruce, Balsam Fir and White birch.)
>
> Wood cost here, in chip form, would be about $C 40 per ton ( about ZAR240
> per ton, or say ZAR265 per tonne delivered within a 40 km haul distance.
Is
> that in the acceptable range, or would raw material costs be very much
less
> in South Africa?
>
> Kindest regards,
>
> Kevin
> ----- Original Message -----
> From: "Kobus" <ventfory@IAFRICA.COM>
> To: <STOVES@LISTSERV.REPP.ORG>
> Sent: Thursday, June 19, 2003 10:54 AM
> Subject: [STOVES] New activated carbon-from-wood plant
>
>
> Construction of a 10,9 Million USD carbon-from-wood plant has begun in
> Estcourt, in western KwaZulu Natal, South Africa. It is scheduled to
start
> production in January 2004, managed by Karbotek, an Italian/South African
> partnership. It is a spin off to the 6,4 Billion USD strategic arms deal
> for the South African Defence Force.
>
> For more information goto:
> http://free.financialmail.co.za/03/0516/business/bbus.htm
> >>>
> Kobus
>

From psanders at ILSTU.EDU Fri Jun 20 09:02:33 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:25 2004
Subject: Gasification for biomass briquettes
In-Reply-To: <000001c33750$404e4ad0$573029c4@biomassenergy>
Message-ID: <FRI.20.JUN.2003.080233.0500.PSANDERS@ILSTU.EDU>

Peter,

The picture did not arrive. Best to send it just to those who request it
(I request it.) because of file size going to all of the Stoves List Serve
(or to Tom Miles who will put it on the internet site.)

About Shimada briquettes, I think of them as about 10 to 12 cm diameter and
15 to 20 cm long. Is that about right? If yes, then their size becomes a
problem with pyrolysis to create charcoal (with the charcoal pieces
probably too large for most charcoal burning stoves, meaning the people
will break it up). I could be totally wrong.

But if correct, then why not make the biomass briquettes smaller to begin
with. I purchased some 5 to 6 cm diameter densified sawdust briquettes in
South Africa, but I know that that machine and another one in Maputo,
Mozambique, are both idle now. I would love to have a reliable supply of
that size of briquette.

I have heard Crispin call his VESTO stove a "semi-gasifier" but not a
full-fledged gasifier.

Also, are you seeking gasifiers for larger purposes (more biomass and a
larger fire)? My largest thus far was with an 8 or 10 inch (20 or 25 cm)
diameter (I do not remember which, and it is in Maputo now, and I am in the
USA until early July). Anyway, it is big, with about 50 cm height of the
fuel chamber for pyrolysis (and charcoal making, if desired.) I was
burning coconut husks (not the hard shells) with far too much heat / flame
(from the combustion of the "smoke") for any reasonable domestic use. That
unit plus your briquettes might run a bakery, with charcoal as the by-product.

Paul

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From Gavin at AA3GENERGI.FORCE9.CO.UK Fri Jun 20 15:22:40 2003
From: Gavin at AA3GENERGI.FORCE9.CO.UK (Gavin Gulliver-Goodall)
Date: Tue Aug 10 18:30:26 2004
Subject: Gasification for biomass briquettes
In-Reply-To: <4.3.1.2.20030619114953.01de4590@mail.ilstu.edu>
Message-ID: <FRI.20.JUN.2003.202240.0100.GAVIN@AA3GENERGI.FORCE9.CO.UK>

My experience of briquettes- compressed small particles - maybe bound in
your circumstances, is that they break down into the small particles again
as they are combusted (or gasified) will be as powder so in which case the
char - if you get any will need briquetting again
In fact the fact that they decompose in a nice controlled way ! is inherent
in the advantages as the combustinon is more complete and air/fuel mixing
more optimal.

- I'm sure AJH will have a view on this.

gavin

Gavin Gulliver-Goodall
3G Energi,

Tel +44 (0)1835 824201
Fax +44 (0)870 8314098
Mob +44 (0)7773 781498
E mail Gavin@3genergi.co.uk <mailto:Gavin@3genergi.co.uk>

The contents of this email and any attachments are the property of 3G Energi
and are intended for the confidential use of the named recipient(s) only.
They may be legally privileged and should not be communicated to or relied
upon by any person without our express written consent. If you are not an
addressee please notify us immediately at the address above or by email at
Gavin@3genergi.co.uk <mailto:Gavin@3genergi.co.uk>. Any files attached to
this email will have been checked with virus detection software before
transmission. However, you should carry out your own virus check before
opening any attachment. 3G Energi accepts no liability for any loss or
damage that may be caused by software viruses.

-----Original Message-----
From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On Behalf
Of Paul S. Anderson
Sent: Thursday, June 19, 2003 18:08
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] Gasification for biomass briquettes

Peter (and Ron and all),

Please include me in any discussion on biomass briquettes and their
gasification.

Seems that Peter is not on the Stoves List Serve, and maybe this topic
should (eventually, but not immediately) have a separate (side) discussion
once we have identified the people who want to do this discussion. (Then
we can send periodic up-dates to the whole Stoves list.)

So others should express their interest to be sure that they join with
"Peter, Paul and Ron." Should include Richard Stanley and others. We
need to compile a list (not a list-serve) so that everyone gets copies of
the messages.

In Mozambique, with my co-worker Apolinario Malawene, we are making biomass
briquettes for burning in small gasifiers. Our materials for the
briquettes are like Richard Stanley's (he got us started with this), but
with diameters of about 5 or 6 cm, and no holes in the center. We are not
far enough along to say if we want to save the charcoal or want to try to
burn it in location in the stoves.

Peter, how dense are your briquettes? The compaction of ours is low, and
after gasification they are very weak and would not hold up well to
handling and transport.

But I know that gasifier (pyrolyzed) corn cobs are great little
"briquettes" that can be transported as charcoal.

Paul
Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From crispin at NEWDAWN.SZ Sat Jun 21 05:45:52 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:26 2004
Subject: Gasification for biomass briquettes - Paul
Message-ID: <SAT.21.JUN.2003.114552.0200.CRISPIN@NEWDAWN.SZ>

Dear Paul

Nice to hear from you.

>About Shimada briquettes, I think of them as
>about 10 to 12 cm diameter and 15 to 20
>cm long.

That seems pretty large. Does it have a 'linear' burn? What is the sort of
heat/gas generation over time? I was wondering if having one about 1/2 the
size (in height) would be better in an enclosed stove so that the amount of
heat can be held down for long simmers. They do tend to get roaring after
they are partly burned.

Peter Gathercole in Dar es Salaam who wrote to the group a day or so ago is
working on biomass briquettes (in general) and is thinking about trying to
gasify them because he sees a future in making the charcoal into briquettes.
It seems to me that the height and as you point out, the amount of charcoal
produced at a time, would be nowhere near optimal. I think the top
charcoal would be burned off as the bottom lights up.

>I purchased some 5 to 6 cm diameter densified sawdust briquettes in
>South Africa,

I hear there are 6 such machines, perhaps not including the German one at
Chet Industries in Butterworth which is a 50mm one - 60 HP!

>I would love to have a reliable supply of
>that size of briquette.

Is you contact Walter Ebling at PMSA (++27) 11-397-3755 he might be able to
get you in contact with a guy who is compressing peanut shells. Walter has
some samples in his closet at work. Hard as a rock - a round-cornered
square.

>I have heard Crispin call his VESTO stove a "semi-gasifier"
>but not a full-fledged gasifier.

I have tried to make it burn all the fuel while still having some measure of
control over the total heat output. There is definitely a gasifying phase
when new wood is being burned (with the heat control set to 'low') in the
absence of enough air, as a way of keeping the heat under control. It does
seem to work, but perhaps I will have to increase the amount of secondary
air available.

For the moment we have dropped the secondary air controller as the
grate+downward air flow pre-heating arrangement seems to be able to regulate
the air adequately by itself - it was a big of mechanical overkill. However
the latest emission report I have from Germany shows that when the fire is
reduced (primary air shut off to enter the gasifier mode) the emissions
_can_ increase by a lot. Just when, during the burn, and in what state the
fuel is when the emissions increase is not clear yet to me. For example, if
it is during a charcoal-burning phase before a refueling point, I can
overcome that by increasing the amount of secondary air provided, and return
to having that amount controlled by an additional part. This makes the
stove wonderful as a lab device showing that phenomenal results are
possible, but Rina says it makes the stove too difficult to train people to
use optimally - and she is right. They tend to leave everything open
because they are not used to fiddling with devices to reduce invisible
gases.

Whatever is going to sell well (meaning, in statistically and
environmentally meaningful quantities) is going to have to be very simple to
train and use. Two controls are probably one too many.

By the way, the German Prof says that he measured a 3% _increase_ in PHU
when the Vesto fire was fully turned down. That is when the overall gas
flow is slowest. I have shown the same thing but it does seem to contradict
what some are saying about heat transfer.

On the issue of total emissions, I need to find out if the total exposure to
CO by a cook is less when:

1. the primary air is open and more fuel is burning (more total fuel
used, more total CO but at a lower concentration). The CO2:CO ratio is
about 50:1 in this condition.

or

2. the primary air is closed and it is gasifying the wood, burning much
less total wood per 'cook' but at some point generating a higher CO content
(at the end of the burn?).

If the CO production is only high at the very end (something the Harare lab
found with our Shisa Stove) then the recommended practice of opening the
primary air when the charcoal is made and starts to burn needs to be
emphasized. Burning charcoal in a gasifier / semi-gasifier seems to produce
a high CO concentration - presumably due to inadequate secondary air, as Tom
(thanks) has pointed out with his required A/F numbers.

If I am going to retain a single controller, I may have to provide unneeded
secondary air early on in order to have lower CO numbers later on in a
air-choked charcoal burn. That will lower the CO2 concentration further
early on through dilution. BTW the Prof got numbers like 175ppm CO 200mm
above the pot (exit gases) and Harare got 65ppm, possibly by lighting a
smaller fire - not sure. If so, it points to a need for more secondary air.

Regards
Crispin

From rstanley at LEGACYFOUND.ORG Sat Jun 21 06:39:04 2003
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:26 2004
Subject: Pyrolification of biomass briquettes
Message-ID: <SAT.21.JUN.2003.133904.0300.>

Paul, Gavin et al.,

We have also been looking to into gassification of our "Holey" fuel briquettes
too. An initial continuous feed, gassifying stove design emerged in concept
through the kind and ingenious efforts of Lenny Hansen. This design has been
augmented by discussions with Ron and most recently Kobus Venter who has tanke
te initiativee further with the promise of actually making a prototype based on
engineered criteria and his own unique contacts inte stives list and other
newsgrouos and local contacts. Once Kobus has the chance to test it with
briquettes just send down to him, we will post the findings (+& -) out to you
all.

As to char or no char pyrolisis or gassification, do not yet know what would be
left because we have not attempted same. I agree that a re-briquetting process
would have to be undertaken to utilise any resulting char which is agreed,
quite friable. Fortunately however, the process for compaction and briquetting
will have already been established by fact of having the holey briquette
available in the first place. Technically at least it would be an easy matter
to simply re process the char into a solid briquete. As mentioned to Ron Larson
earlier though, some form of clay or corn starch binder (=the fines off the
local maize/posho/ chigayo/molino milling floor, or those residuals from
cassava processing for example) would be needed but that should pose no
problem. The issue is not technical but one of cost and other options available
for the producer. What we experience is that the trained microentprepreneurs
will tend to simply produce the initial briquette out of charcoal fines (can
utilise up to 45% by volume) using some form of binder by way of more fibrous
material and/or the above mentioned wastes.

As a side bar, there arises in theory a certain positive irony in
producing charcoal fines-based biquettes in that because of the
dilution factor, overall charcoal demand is actually reduced. Here
in Kampala for example 30,000 tones of wastes (as fines and dust) are
generated every year, right at the urban retail seller's sites,
scatterd as they typically are, throughout the city. This waste is
generated by 70% of its 1.2 million citisens, consuming, very
conservatively, 120 tons of raw charcoal each year.

Thats a lot of readily available charcoal waste to play with.

If one incorporated the 30,000 tons of charcoal waste as 40% of the
overall fuel briquette (weight and volume are about equal for dry
biomass and charcoal fines for this discussion) and if one
extrapolates the known daily holey briquette consumption figures from
similar cultures in neighboring nations, one comes to the conclusion
that utilisation of these wastes will reduce overall demand raw
charcoal We calculate reduction in demand for raw charcoal by as much
as 25% in fact. How this compares to reprocessing char from
pyrolosis or "pyrolification", into charcoal for resale in the same
open market, is a good question.

I know that making a briquette locally in Kampala on a local 6 person trained
microentrepreneur team basis, using an enticing local street daily wage of 4000
Uganda Shillings (Ush) --- 2000 Ush =1 USD currently---would cost about 2.4 US
cents. This results in a daily cost to the 6 person family (extrapolating from
regional family structure and consumption figures) of between 28 and 30 US
cents per day as a delivered cost. By comparison, charcoal costs in Kampala,
about 10,000 - 12,000 Ush per 50-60 kg bag and (assuming that all the
charcoal is as good as what is shown on top) last about two weeks for same
family. The cost per family per day or charcoal is therefore about 40 - 43 US
cents per day. Add in slippage wastes etc., etc. and the holey briquette would
seems fairly competitive at least before one plunges into real local market
interests. Charcoal-based briquetes may be preferred for meat and high heat
applications but often, one simply wants to steep beans or just keep water warm
all day long, or just induce aromas using traditional plants and herbs which
drive away mossies in the evening-- all of which requires quite different
blends. Its a rather big arena, this cooking preferences issue and it seems
that we are just on the proverbial "tip of the iceberg".

Tulabagane',

Richard Stanley
Kampala

 

Gavin Gulliver-Goodall wrote:

> My experience of briquettes- compressed small particles - maybe bound in
> your circumstances, is that they break down into the small particles again
> as they are combusted (or gasified) will be as powder so in which case the
> char - if you get any will need briquetting again
> In fact the fact that they decompose in a nice controlled way ! is inherent
> in the advantages as the combustinon is more complete and air/fuel mixing
> more optimal.
>
> - I'm sure AJH will have a view on this.
>
> gavin
>
> Gavin Gulliver-Goodall
> 3G Energi,
>
> Tel +44 (0)1835 824201
> Fax +44 (0)870 8314098
> Mob +44 (0)7773 781498
> E mail Gavin@3genergi.co.uk <mailto:Gavin@3genergi.co.uk>
>
> The contents of this email and any attachments are the property of 3G Energi
> and are intended for the confidential use of the named recipient(s) only.
> They may be legally privileged and should not be communicated to or relied
> upon by any person without our express written consent. If you are not an
> addressee please notify us immediately at the address above or by email at
> Gavin@3genergi.co.uk <mailto:Gavin@3genergi.co.uk>. Any files attached to
> this email will have been checked with virus detection software before
> transmission. However, you should carry out your own virus check before
> opening any attachment. 3G Energi accepts no liability for any loss or
> damage that may be caused by software viruses.
>
> -----Original Message-----
> From: The Stoves Discussion List [mailto:STOVES@LISTSERV.REPP.ORG]On Behalf
> Of Paul S. Anderson
> Sent: Thursday, June 19, 2003 18:08
> To: STOVES@LISTSERV.REPP.ORG
> Subject: Re: [STOVES] Gasification for biomass briquettes
>
> Peter (and Ron and all),
>
> Please include me in any discussion on biomass briquettes and their
> gasification.
>
> Seems that Peter is not on the Stoves List Serve, and maybe this topic
> should (eventually, but not immediately) have a separate (side) discussion
> once we have identified the people who want to do this discussion. (Then
> we can send periodic up-dates to the whole Stoves list.)
>
> So others should express their interest to be sure that they join with
> "Peter, Paul and Ron." Should include Richard Stanley and others. We
> need to compile a list (not a list-serve) so that everyone gets copies of
> the messages.
>
> In Mozambique, with my co-worker Apolinario Malawene, we are making biomass
> briquettes for burning in small gasifiers. Our materials for the
> briquettes are like Richard Stanley's (he got us started with this), but
> with diameters of about 5 or 6 cm, and no holes in the center. We are not
> far enough along to say if we want to save the charcoal or want to try to
> burn it in location in the stoves.
>
> Peter, how dense are your briquettes? The compaction of ours is low, and
> after gasification they are very weak and would not hold up well to
> handling and transport.
>
> But I know that gasifier (pyrolyzed) corn cobs are great little
> "briquettes" that can be transported as charcoal.
>
> Paul
> Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
> Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
> Dept of Geography - Geology (Box 4400), Illinois State University
> Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
> E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From rstanley at LEGACYFOUND.ORG Sat Jun 21 07:04:56 2003
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:26 2004
Subject: Gasification for biomass briquettes - Paul
Message-ID: <SAT.21.JUN.2003.140456.0300.>

Dear Crispen, Kobus, Paul, et al,

Did you ever consider that with the given possibility of controlling the height
of the manufactured briquette, one could locate the secondary holes, such
they would only be exposed as the briquettes burned down into the ember stage
which I ('m guessing) is the right time for introducing such ?

At the same time, at least with the loser density (.22 - .30 g/cc) hand made
wet process briquettes, a considerable amount of ash is produced. The bottom
grates of the same stove can be sized to limit ash fall off through the grate,
and hence block off primary air flow-- again at the right stage of the burn. Is
it too far fetched to conceive of a stove designed around the fuel which would
not require adjustments with the cost and training implications indicated in
the discussions below ?

We are now into development of a gassifier-pyrolosis, or perhaps a "pyrolifier"
stove for the holey briquettes; hence my interest.

Richard Stanley
Kampala

 

Crispin wrote:

> Dear Paul
>
> Nice to hear from you.
>
> >About Shimada briquettes, I think of them as
> >about 10 to 12 cm diameter and 15 to 20
> >cm long.
>
> That seems pretty large. Does it have a 'linear' burn? What is the sort of
> heat/gas generation over time? I was wondering if having one about 1/2 the
> size (in height) would be better in an enclosed stove so that the amount of
> heat can be held down for long simmers. They do tend to get roaring after
> they are partly burned.
>
> Peter Gathercole in Dar es Salaam who wrote to the group a day or so ago is
> working on biomass briquettes (in general) and is thinking about trying to
> gasify them because he sees a future in making the charcoal into briquettes.
> It seems to me that the height and as you point out, the amount of charcoal
> produced at a time, would be nowhere near optimal. I think the top
> charcoal would be burned off as the bottom lights up.
>
> >I purchased some 5 to 6 cm diameter densified sawdust briquettes in
> >South Africa,
>
> I hear there are 6 such machines, perhaps not including the German one at
> Chet Industries in Butterworth which is a 50mm one - 60 HP!
>
> >I would love to have a reliable supply of
> >that size of briquette.
>
> Is you contact Walter Ebling at PMSA (++27) 11-397-3755 he might be able to
> get you in contact with a guy who is compressing peanut shells. Walter has
> some samples in his closet at work. Hard as a rock - a round-cornered
> square.
>
> >I have heard Crispin call his VESTO stove a "semi-gasifier"
> >but not a full-fledged gasifier.
>
> I have tried to make it burn all the fuel while still having some measure of
> control over the total heat output. There is definitely a gasifying phase
> when new wood is being burned (with the heat control set to 'low') in the
> absence of enough air, as a way of keeping the heat under control. It does
> seem to work, but perhaps I will have to increase the amount of secondary
> air available.
>
> For the moment we have dropped the secondary air controller as the
> grate+downward air flow pre-heating arrangement seems to be able to regulate
> the air adequately by itself - it was a big of mechanical overkill. However
> the latest emission report I have from Germany shows that when the fire is
> reduced (primary air shut off to enter the gasifier mode) the emissions
> _can_ increase by a lot. Just when, during the burn, and in what state the
> fuel is when the emissions increase is not clear yet to me. For example, if
> it is during a charcoal-burning phase before a refueling point, I can
> overcome that by increasing the amount of secondary air provided, and return
> to having that amount controlled by an additional part. This makes the
> stove wonderful as a lab device showing that phenomenal results are
> possible, but Rina says it makes the stove too difficult to train people to
> use optimally - and she is right. They tend to leave everything open
> because they are not used to fiddling with devices to reduce invisible
> gases.
>
> Whatever is going to sell well (meaning, in statistically and
> environmentally meaningful quantities) is going to have to be very simple to
> train and use. Two controls are probably one too many.
>
> By the way, the German Prof says that he measured a 3% _increase_ in PHU
> when the Vesto fire was fully turned down. That is when the overall gas
> flow is slowest. I have shown the same thing but it does seem to contradict
> what some are saying about heat transfer.
>
> On the issue of total emissions, I need to find out if the total exposure to
> CO by a cook is less when:
>
> 1. the primary air is open and more fuel is burning (more total fuel
> used, more total CO but at a lower concentration). The CO2:CO ratio is
> about 50:1 in this condition.
>
> or
>
> 2. the primary air is closed and it is gasifying the wood, burning much
> less total wood per 'cook' but at some point generating a higher CO content
> (at the end of the burn?).
>
> If the CO production is only high at the very end (something the Harare lab
> found with our Shisa Stove) then the recommended practice of opening the
> primary air when the charcoal is made and starts to burn needs to be
> emphasized. Burning charcoal in a gasifier / semi-gasifier seems to produce
> a high CO concentration - presumably due to inadequate secondary air, as Tom
> (thanks) has pointed out with his required A/F numbers.
>
> If I am going to retain a single controller, I may have to provide unneeded
> secondary air early on in order to have lower CO numbers later on in a
> air-choked charcoal burn. That will lower the CO2 concentration further
> early on through dilution. BTW the Prof got numbers like 175ppm CO 200mm
> above the pot (exit gases) and Harare got 65ppm, possibly by lighting a
> smaller fire - not sure. If so, it points to a need for more secondary air.
>
> Regards
> Crispin

From solar1 at ZUPER.NET Sat Jun 21 13:18:11 2003
From: solar1 at ZUPER.NET (Sobre la Roca: Energ=?ISO-8859-1?B?7Q==?=a Solar para el
Desarrollo)
Date: Tue Aug 10 18:30:26 2004
Subject: Improved cook stove presentation - request for information
Message-ID: <SAT.21.JUN.2003.131811.0400.SOLAR1@ZUPER.NET>

Dear stovers and solar cookers, et. al,
I am better known on the solar cooking list, although I read and have
learned a lot from all on both. I work with a project combining solar
cooking, retained heat cooking and efficient wood cooking into a system we
call Ecological Cookers. We use the rocket principals in our improved wood
cooker, and we have shared information with Dean Still since 1999. We work
in Bolivia and southern Peru.

I have been invited to make a presentation at a Global Village Energy
Partnership Regional Conference for Latin America and Caribbean. The topic
I was given specifically is, Improved Cookstoves: An essential Element in
Bettering Household Health (roughly translated from the Spanish - ?Cocinas
mejoradas: un mejoramiento esencial de la salud domestica? ).

Since policy makers and international donors such as World Bank and USAID,
etc. from most of the Central and South American countries will attend this
conference I think it is a great platform to report on how improved stoves
and solar cookers in different countries are being disseminated.

With that offer in mind, if you would like information about your work
included in the presentation and proceedings please send me the following,
according to this format...
1. Name and location of program
2. Executers and financers of the program (with contact information), cost
of project to date.
3. A 2- 4 paragraph summary of the program, history, results so far, future
projections, perceived needs. What makes it a good program? How it could be
improved? Future needs?
4. Who is benefiting and how many participants
5. Type of improved stove or charcoal burner
6. How stoves are being delivered, costs, micro-credits
7. Measurable impact on health - beneficiaries
8. 1 -4 photographs in jpg format.

Please send me this information by Tuesday June 24.

I want to include programs from Latin America as well as Asia and Africa to
give a comparison, and hopefully impact the donor organizations with a
knowledge of the volume of work being executed. As you know there has been
little attention given to funding stove projects. Perhaps your project
information can help change that syndrome.

Please let me know what you think.

Un abrazo
David
--
"Sustainable development meets the needs of the present without compromising
the ability of future generations to meet their own needs."

David Whitfield
Director
Centro de Desarrollo en Energ?a Solar
P.O. Box 4723
La Paz Bolivia South America
591-2-2414882 office 591 715 16356 La Paz or 774 24269
Cochabamba cellular

solar1@zuper.net

dewv@yahoo.com

http://www.solarcooking.org/media/broadcast/whitfield/bio-whitfield.htm

http://www.thehungersite.com

From cree at DOWCO.COM Sat Jun 21 14:49:20 2003
From: cree at DOWCO.COM (JOHN OLSEN)
Date: Tue Aug 10 18:30:26 2004
Subject: biomass briquettes
In-Reply-To: <002b01c337da$07828ba0$2a47fea9@md>
Message-ID: <SAT.21.JUN.2003.114920.0700.CREE@DOWCO.COM>

The SHIMADA produces 2 distinct products by extruding dry Biomass.
1.The "Heatlog", for stoves and fireplaces,and boilers,etc., is 6.5cm width,
cut to any length, normal size 25 cm.
2 The "Sizzler", for barbecue cooking,(replacing charcoal),6.5cm x 4cm
each of course has the centre hole. (holey briquette)
regards
John Olsen
see for pics
http://www.heatloginc.com/

From tombreed at ATTBI.COM Sat Jun 21 08:22:02 2003
From: tombreed at ATTBI.COM (Tom Reed)
Date: Tue Aug 10 18:30:26 2004
Subject: Toplit Updraft gasifier nomenclature?
Message-ID: <SAT.21.JUN.2003.062202.0600.TOMBREED@ATTBI.COM>

Dear Ron and all:

When I first developed the stove gasifier in 1985 I used the name
"Upsidedowndraft gasifier stove", since it was an "upsidedown" version of
the WWII downdraft gasifiers I know a lot about.
Sort of a joke... ; (

I found out soon that "upside down" is not a familiar work to foreigners, so
I changed it to "inverted downdraft" gasifier stove. That was fine in the
gasification world.

Then I worked with Ron Larson about 1995 and he wanted to call it a
"charcoal making stove" or a top lit stove". Lots of confusion outside the
gasifier field, and I would like to be both clear and descriptive.
~~~~~~~
How about "Toplit-Updraft" WoodGas Cookstove? It then contains instructions
for lighting which is the principle difference from "Bottom-Lit-Updraft"
gasifiers (that make lots of smoke and burn inefficiently).

Thoughts???

TOM REED
Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax

Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax

From adkarve at PN2.VSNL.NET.IN Sun Jun 22 12:01:52 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:26 2004
Subject: Gasification for biomass briquettes
Message-ID: <SUN.22.JUN.2003.213152.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Ron,
we use primarily light agrowaste and leaf litter from tree plantations as the rq material for making our charcoal. Because of the extremely low density of the target biomass it is too costly to transport it to a central charcoaling unit. We have therefore developed a portable unit which is taken to the field where the light agrowaste is available. The process of pyrolysis generates a lot of heat, but It is not possible to use the waste heat at that site.
Yours
A.D.Karve
-----Original Message-----
From: Ron Larson <ronallarson@qwest.net>
To: Peter <peter.gathercole@raha.com>; Stoves <STOVES@LISTSERV.REPP.ORG>
Cc: adkarve@PN2.VSNL.NET.IN <adkarve@PN2.VSNL.NET.IN>
Date: Thursday, June 19, 2003 6:01 PM
Subject: RE: Gasification for biomass briquettes

Peter (cc AD and Stoves):

I am taking the liberty of sending your request for information on efficiently using the pyrolysis gases from your charcoal briquette making operation on to our full "stoves" list. This is to ask all "stovers" to assist as this is a most important question.

There are a number of people on the list who are using gasifiers for producing gases for engines and/or stoves. There are also others developing pyrolysis units - attempting to get charcoal. My own interest is in using small cookstoves to produce charcoal as a co-product. I feel this is at a stage where persons like yourself need to see if this could be profitable - you supply the fuel in a suitable biomass form (pillows or cylinders, etc) and the stove user returns charcoal to you for your processing into a final product. There is plenty of material on this type of charcoal-making stove in the early archives of "stoves" - but no commercial activity yet. More development is needed. We have also talked about using the pyrolysis gases for larger commercial operations like bakeries, pottery kilns, cement making, or any place where biomass is being consumed for large thermal operations. In all of these, I believe charcoal can be a useful and income-generating sideline. So far, I am not aware of anyone doing this - the pyrolysis gases are usually exhausted - and as you point out - should not be. Here is hoping you will have generated the interest of some manufacturer of gasifiers to instead produce a charcoal maker. I just did a google search on "India gasifier manufacturers" and found many lists. Perhaps Dr. Karve or others in India can tell who has a unit that might emphasize charcoal rather than gases.

Several more answers below.
-----Original Message-----
From: Peter [mailto:peter.gathercole@raha.com]
Sent: Thursday, June 19, 2003 10:53 AM
To: ronallarson@qwest.net
Cc: adkarve@PN2.VSNL.NET.IN
Subject: Gasification for biomass briquettes

Dear Ron/Mr Karve/Paul,

I am Peter Gathercole of Biomass Energy Tanzania Limited and we are developing the biomass briquetting market in Tanzania. I have been in contact with NEWDAWN and Crispin who has kindly send me your contact details for advise on the questions I raised below. Would it be possible to obtain some imfo from you guys on a way ahead for us to encourage the use of the product by removing the volatiles efficiently and usefully, which then enable the briquettes to be more user friendly than without carbonisation. We are looking at many issues relating to improved stoves (NEWDAWN) and locally made insulated units with increase secondary air ways to improve combustion and use up the gases rather than waste them.

If you can assist I would be highly appreciative.

Please find questions I raised to Crispin:

Dear Crispin,

We are looking at extracting the volatiles from our biomass briquettes on a commercial basis to improve the saleability of the briquette product and also to harness the gas from the wood waste. Do you have any base date on wood fuel gas constituents or composition of the gases, on a variety of biomass woody wastes.

(RWL): I do not have much other than that there will be a tremendous array of constituents - and of course many pyrolyzers are attempting to condense and capture various liquids. The gases are primarily methane, CO and hydrogen. Your main concern will be that the effluent gases not contain too much moisture vapor - so that fairly dry biomass must be the starting point. Otherwise, the gases will not be ignitable. here is hoping that people like Dr. Michael Antal or Dr. Tom reed can answer your question with full literature citations. There is plenty of scientific literature on this subject.

Also any data on gasifiers which could be used on small scale to produce such gas and leave a carbonised briquette which could then be sold. We are looking at a more efficient way of empowering the current charcoal producers to continue with briquettes and harness the energy within their communities to produce alternative charcoal, cook at the same time on the gas extracted. (communal cooking and making charcoal).

(RWL): I would urge you not to use the word "gasifier" to describe what you are doing - I prefer "pyrolyzer." I find that the people expert in "gasifiers" are interested in minimizing the production of charcoal.

Best of luck.

Ron

BRs

Peter Gathercole

Development Director

Biomass Energy Tanzania Limited

PO Box 31748, Dar Es Salaam, Tanzania

Tel/Fax: +255 22 2666667 Cell:+ 255 (0)744 785340

The data contained within this email and any accompanying or attached file is legally privileged. The information is intended only for the use of the individual or entity for whom it was intended. If you are not the intended recipient, you are hereby notified that any disclosure, copying, storing, distribution or taking of any action in reliance on the contents of this email is strictly prohibited. If you have received this email in error, you please notify us immediately by telephone, fax or return email and thereafter delete the transmission you have received. We shall be pleased to reimburse any reasonable costs incurred.

From psanders at ILSTU.EDU Sun Jun 22 14:43:28 2003
From: psanders at ILSTU.EDU (Paul S. Anderson)
Date: Tue Aug 10 18:30:26 2004
Subject: Grand Challenges (and stoves)
Message-ID: <SUN.22.JUN.2003.134328.0500.PSANDERS@ILSTU.EDU>

Stovers,

A week ago I sent out the draft of an item about the Gate's funding on
Grand Challenges in Global Health, and about stoves being part of the
solution for serious respiratory diseases.

Where are you, stovers? ONE reply or comment came back to me. Another
private discussion said "we already know what we need to know about how
stoves work".

Am I totally out of touch? I thought we needed a LOT of work about stoves
in relation to less smoke inside of the homes of impoverished people.

I will finalize my 2 pages and send them in late tomorrow. I hope that
stoves make the "short list" for the Grand Challenges to be funded.

Meanwhile, I am finishing my Juntos gasifer that I will take to the Biomass
Energy meeting in Morelia, Mexico this week. Each time I make one of these
Top-Lit Up-Draft (TLUD) pyrolysis gasifiers, I learn something new.

Paul

Paul S. Anderson, Ph.D., Fulbright Prof. to Mozambique 8/99 - 7/00
Rotary University Teacher Grantee to Mozambique >10 mo of 2001-2003
Dept of Geography - Geology (Box 4400), Illinois State University
Normal, IL 61790-4400 Voice: 309-438-7360; FAX: 309-438-5310
E-mail: psanders@ilstu.edu - Internet items: www.ilstu.edu/~psanders

From kchisholm at CA.INTER.NET Sun Jun 22 15:55:38 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:26 2004
Subject: Grand Challenges (and stoves)
Message-ID: <SUN.22.JUN.2003.165538.0300.KCHISHOLM@CA.INTER.NET>

Dear Paul
----- Original Message -----
From: "Paul S. Anderson" <psanders@ILSTU.EDU>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Sunday, June 22, 2003 3:43 PM
Subject: [STOVES] Grand Challenges (and stoves)

> Stovers,
...del...>
> Am I totally out of touch? I thought we needed a LOT of work about stoves
> in relation to less smoke inside of the homes of impoverished people.
>
A stovepipe discharging outside teh living space will solve the problem,
wouldn't you say?

Kevin

From tombreed at ATTBI.COM Sun Jun 22 12:09:35 2003
From: tombreed at ATTBI.COM (Tom Reed)
Date: Tue Aug 10 18:30:26 2004
Subject: "Gasification" vs "pyrolyser" vs combustor
Message-ID: <SUN.22.JUN.2003.100935.0600.TOMBREED@ATTBI.COM>

Dear Ron and All:

Ron Larson at "stoves" said

> (RWL): I would urge you not to use the word "gasifier" to describe
> what you are doing - I prefer "pyrolyzer." I find that the people expert
in
> "gasifiers" are interested in minimizing the production of charcoal.
>
I would like to take issue with Ron on this - too bad we get so little time
to discuss these matters, considering we are only 1 mile apart (as the crow
flies).

I have been working in the field of biomass pyrolysis, combustion and
gasification since 1974, so I try to be very careful of my use of words in a
field where there are many redundant terms.

I developed the "inverted downdraft gasifier" in 1985 while traveling in
Africa and gave it that name because it was derived from the conventional
downdraft gasifiers that I had worked with extensively. I soon discovered
that inverted downdraft is in a sense a double negative, so could be
confusing to anyone not familiar with downdraft gasifiers, which is
99.9999999% of the world.

I recently in an "I surrender" Email recommended that it might be called a
"toplit-updraft gasifier, since the flow of air is like an updraft gasifier,
but it is lit on top. This is all important, since lighting an updraft
gasifier on the bottom (conventional) burns all the charcoal and liberates
copious tars and makes tall flare flames.

Meanwhile, Ron Larson, when I first showed it to him in 1995, decided,
independently, to call it a "charcoal making gasifier", then later a "toplit
gasifier". Now he recommends that we call it a "pyrolyser". Shifting
sands!

~~~~~~~~~~~~~~
Conventional "slow pyrolysis" produces charcoal, gas and condensable
volatile materials (tars) in about equal proportions and was practiced
widely from Egyptian times through 1950 when the last plant closed down in
the U.S. "Fast Pyrolysis" has become the darling of the liquid fuel teams,
since it can produce > 60% liquid tar-fuel from biomass. Is that what Ron
is recommending as a name?

~~~~~~~~~~~~~~
All downdraft gasifiers produce 5-25% charcoal, but their major intent is to
produce a combustible gas for heat or engines. They also produce typically
0.1% volatile tars that must be removed. But since their intent is to
produce gas, they are called downdraft gasifiers.

~~~~~~~~~~~~~
We will continue to call our forced draft toplit-updraft gasifier a "WoodGas
stove", since it makes a combustible gas which can be burned cleanly with
the right proportion of combustion/gasification air (about 6/1). If Ron
wants to call it a pyrolyser (which doesn't draw attention to the fact that
75% of the energy comes off as a gas) I can't stop him.

Comments?

Yours for better and standard nomenclature - Tom
- The BEF

 

Dr. Thomas B. Reed
1810 Smith Rd., Golden, CO 80401
tombreed@attbi.com; 303 278 0558 Phone; 303 265 9184 Fax
----- Original Message -----
From: "Ron Larson" <ronallarson@QWEST.NET>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, June 19, 2003 6:36 AM
Subject: Re: [STOVES] Gasification for biomass briquettes

> Peter (cc AD and Stoves):
>
> I am taking the liberty of sending your request for information on
> efficiently using the pyrolysis gases from your charcoal briquette making
> operation on to our full "stoves" list. This is to ask all "stovers" to
> assist as this is a most important question.
>
> There are a number of people on the list who are using gasifiers for
> producing gases for engines and/or stoves. There are also others
developing
> pyrolysis units - attempting to get charcoal. My own interest is in using
> small cookstoves to produce charcoal as a co-product. I feel this is at a
> stage where persons like yourself need to see if this could be
profitable -
> you supply the fuel in a suitable biomass form (pillows or cylinders, etc)
> and the stove user returns charcoal to you for your processing into a
final
> product. There is plenty of material on this type of charcoal-making
stove
> in the early archives of "stoves" - but no commercial activity yet. More
> development is needed. We have also talked about using the pyrolysis
gases
> for larger commercial operations like bakeries, pottery kilns, cement
> making, or any place where biomass is being consumed for large thermal
> operations. In all of these, I believe charcoal can be a useful and
> income-generating sideline. So far, I am not aware of anyone doing this -
> the pyrolysis gases are usually exhausted - and as you point out - should
> not be. Here is hoping you will have generated the interest of some
> manufacturer of gasifiers to instead produce a charcoal maker. I just
did
> a google search on "India gasifier manufacturers" and found many lists.
> Perhaps Dr. Karve or others in India can tell who has a unit that might
> emphasize charcoal rather than gases.
>
> Several more answers below.
> -----Original Message-----
> From: Peter [mailto:peter.gathercole@raha.com]
> Sent: Thursday, June 19, 2003 10:53 AM
> To: ronallarson@qwest.net
> Cc: adkarve@PN2.VSNL.NET.IN
> Subject: Gasification for biomass briquettes
>
>
> Dear Ron/Mr Karve/Paul,
>
> I am Peter Gathercole of Biomass Energy Tanzania Limited and we are
> developing the biomass briquetting market in Tanzania. I have been in
> contact with NEWDAWN and Crispin who has kindly send me your contact
details
> for advise on the questions I raised below. Would it be possible to obtain
> some imfo from you guys on a way ahead for us to encourage the use of the
> product by removing the volatiles efficiently and usefully, which then
> enable the briquettes to be more user friendly than without carbonisation.
> We are looking at many issues relating to improved stoves (NEWDAWN) and
> locally made insulated units with increase secondary air ways to improve
> combustion and use up the gases rather than waste them.
>
>
>
> If you can assist I would be highly appreciative.
>
>
>
> Please find questions I raised to Crispin:
>
>
>
> Dear Crispin,
>
> We are looking at extracting the volatiles from our biomass briquettes
on
> a commercial basis to improve the saleability of the briquette product and
> also to harness the gas from the wood waste. Do you have any base date on
> wood fuel gas constituents or composition of the gases, on a variety of
> biomass woody wastes.
>
>
>
> (RWL): I do not have much other than that there will be a
tremendous
> array of constituents - and of course many pyrolyzers are attempting to
> condense and capture various liquids. The gases are primarily methane, CO
> and hydrogen. Your main concern will be that the effluent gases not
contain
> too much moisture vapor - so that fairly dry biomass must be the starting
> point. Otherwise, the gases will not be ignitable. here is hoping that
> people like Dr. Michael Antal or Dr. Tom reed can answer your question
with
> full literature citations. There is plenty of scientific literature on
this
> subject.
>
>
>
> Also any data on gasifiers which could be used on small scale to
produce
> such gas and leave a carbonised briquette which could then be sold. We are
> looking at a more efficient way of empowering the current charcoal
producers
> to continue with briquettes and harness the energy within their
communities
> to produce alternative charcoal, cook at the same time on the gas
extracted.
> (communal cooking and making charcoal).
>
>
>
>
> Best of luck.
>
> Ron
>
>
>
> BRs
>
>
>
>
>
> Peter Gathercole
>
> Development Director
>
> Biomass Energy Tanzania Limited
>
> PO Box 31748, Dar Es Salaam, Tanzania
>
> Tel/Fax: +255 22 2666667 Cell:+ 255 (0)744 785340
>
> The data contained within this email and any accompanying or attached
file
> is legally privileged. The information is intended only for the use of the
> individual or entity for whom it was intended. If you are not the intended
> recipient, you are hereby notified that any disclosure, copying, storing,
> distribution or taking of any action in reliance on the contents of this
> email is strictly prohibited. If you have received this email in error,
you
> please notify us immediately by telephone, fax or return email and
> thereafter delete the transmission you have received. We shall be pleased
to
> reimburse any reasonable costs incurred.

From rstanley at LEGACYFOUND.ORG Mon Jun 23 05:04:42 2003
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:26 2004
Subject: "Gasification" vs "pyrolyser" vs combustor
Message-ID: <MON.23.JUN.2003.120442.0300.>

How about "pyrolifier" whether, top or bottom lit. Just Kidding...

Either way, I just wanted to also say how much I appreciate both of your
contributions Tom and Ron. Thye are to me, unique invaluable and highly
stimulating to those of us field rats out here !

To wit, I am hot into development of a "pyrolifier" stove (for lack of a better
term until we test it for char content) which is to be tailored to our low mass
(.22-.25 g.cc) holey briquette. It would seem that from the discussions, the
hole placement and air induction timing (for primary and more particularly
secondary air) is critical to effective gassification. The benefit of having a
very controlled size and shape of the fuel load (read in our case, two stacked
briquettes (with an overall starting dimension of 10 cm dia x 15 cm height with
30 mm ID core hole) can offer a lot to simplifying the management secondary air
feed and primary air restriction.

My though is that as the briquettes burn off the volatiles and commence
carbonisation "char" stage they of course will be reduced in height . Perhaps
this fact can then be utilised by positioning the secondary air holes such that
they are only esposed as the char stage begins. Perhaps as well, the grate
design can be made such that it tends to clog a bit to restict primary air as
the char stage begins. Tell me if this is too much to ask of a gassifier. If
it can work and we will know in a couple of months, it will markdly upgrade the
heat output of the holey briquette (something many have challenged it on) and
entice a far larger market to its use. Am working with far more analytically
trained Kobus Venter on this and basing the initial design on Lenny Hansen's
conceptual support, although it is being considerably modified by Kobus' use of
a special insulative riser for the combustion chamber.

One final thought on the design and this is from Lenny, concerns the shape of
the exit or cooking surface. We are proposing the use of three equally
space, stepped rails, mounted as spokes inside a funnel shaped cooking surface.
This is to acomodate several different sizes of pot while expanding exit gas
contact and controlling (by virtue of rail thickness) the pass through rate of
said exhasut gas. Most stoves attempt to achieve all this by the addition of
more sleeves or different hole inserts or simply attempt to standardise the pot
but I'm trying to bring the mountain to mohammed here. One size fits all, or
can it ??

Your thoughts ??

Finally, I note that you are both physically close to an enteprising young
engineer named Mike Lupton who is a real driving force behind UC Boulder's
"Engineers without Borders". His group is just about to venture into the stoves
arena in Haiti and perhaps by this email he can get in contact with you and the
group to save himslf a lot of time while possibly adding to the groups overall
knowledge base. His email is as shown in the CC line above. May be entirely out
of turn on this, as you may well already know each other. if so, my apologies
in advance, for any redundancies and presumptions.

Anon

Richard Stanley
Kampala and soon, Ashland Oregon, for July

>
> >
> >

From dstill at EPUD.NET Mon Jun 23 21:21:20 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:26 2004
Subject: Grand Challenges (and stoves)
Message-ID: <MON.23.JUN.2003.182120.0700.DSTILL@EPUD.NET>

Dear Kevin,

This will be a "true stove pipe", in terms of an
"exhaust pipe" that will actually be connected in a sealed fashion to the
combustion zone. By submerging the pot into the stove body, a tight fit to
the pot sends exhaust up the chimney. I'll send a diagram. Hope it works!

All Best,

Dean

From dstill at EPUD.NET Mon Jun 23 23:57:15 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:26 2004
Subject: Fw: [ethos] 5 things
Message-ID: <MON.23.JUN.2003.205715.0700.DSTILL@EPUD.NET>

>The Five Things I Thought About After The ETHOS Testing and Design Seminar
>(Please Comment!!)
>
>1.) The standard VITA water boiling test may not accurately predict how
much
>fuel is used for cooking because A.) Simmering is a longer process (60 to
>120 minutes for beans) than bringing the pot to initial boiling (15
minutes)
>but the time difference is not accounted for in the test. B.) More
>importantly, the water-boiling test credits steam produced in the simmering
>phase but excess steam is not penalized. Water at a rolling boil produces
>much more steam than water at 100C, which is not at a rolling boil. In a
>simple experiment, I put one cup of water in two equal sized pots on a gas
>stove. I used full power to bring each to a rolling boil. One pot was left
>at a rolling boil at full power but the other was held at 100C at a greatly
>reduced and more fuel-efficient power. When all water had evaporated from
>the rolling boil pot, 5/8th of the water remained in the simmering pot. A
>stove with good turn down would make much less steam which is good for fuel
>efficient cooking but bad for scoring high on the WBT.
>2.) I think that Prasad and Sangen in ?Technical Aspects of Wood Burning
>Cookstoves? (1983) were more accurate by stressing the importance of
>efficiency at simmering. They measuring high power initially as a separate
>timed criteria. But in their view, high power performance is mostly
>important for pleasing cooks with rapid boiling times. As they explain,
fuel
>efficiency in a cook stove is more heavily dependent on efficiency of low
>power operation. They show how supposedly inefficient stoves with good turn
>down can use less wood in cooking tests. Page 215. Rob Bailis, Adriana
>Valencia and I had a similar impression when the Jiko used half again as
>much wood as the Rocket in cooking lentils although the scores on the WBT
>were close.
>3.) The Three Stone Fire scores very high in our tests. This result only
>extends a semi buried tradition of the open fire doing well in the WBT. The
>open fire was presumed to be very inefficient by early stove designers. But
>scores of more careful researchers, like Grant Ballard-Tremeer, Tami Bond,
>Emma George, Sam Baldwin, etc, report the three stone fire as doing better
>than many stoves in the WBT. I believe that the possible error in the WBT,
>rewarding not penalizing excess production of steam in the simmering phase
>and exaggerating the importance of the high power phase, artificially
>inflates the open fire scores. I believe that Prasad and Sangen are closer
>to predicting fuel efficiency in cooking by highlighting good turn down and
>simmering performance in their version of the WBT. If we look at the Time
>Under Curve results (suggested by Dr. Alan Berick), and compare with scores
>on the WBT, faults in our WBT equations seem apparent to me.
>4.) I believe that a stove that can simmer efficiently like Lanny?s stove,
>which scored an amazing 6,000 seconds in Time Under Curve, will be most
>efficient in cooking food, especially foods that simmer for a long time. A
>great stove would be able to both efficiently produce high power to boil
>quickly and efficiently turn down power so that heat lost from the pot is
>replaced without generating excess steam i.e., too much heat. Is this about
>10 to 1 turn down?
>5.) It seems reasonable to imagine that many stoves with great turn down
may
>save firewood even if they are imperfect in other respects. The only real
>defect in the open fire is that it goes out easily when sticks are
>withdrawn. Expert operation is required to achieve turndown and ease of use
>reinforces bigger and wasteful fires. Perhaps stoves can easily save
>firewood if they are efficient at delivering Low Power to the pot.
>
>
>

From elk at WANANCHI.COM Tue Jun 24 08:57:52 2003
From: elk at WANANCHI.COM (elk)
Date: Tue Aug 10 18:30:26 2004
Subject: Re-worked website
Message-ID: <TUE.24.JUN.2003.155752.0300.ELK@WANANCHI.COM>

Stovers;

We've just re-worked and updated the Chardust website. www.chardust.com
Please pay a visit Any & all editorial comments, criticisms or questions are
welcome.

rgds;
elk

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

From adkarve at PN2.VSNL.NET.IN Mon Jun 23 23:26:56 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:26 2004
Subject: Charcoal from bamboo
Message-ID: <TUE.24.JUN.2003.085656.0530.ADKARVE@PN2.VSNL.NET.IN>

Bamboo is one of the fastest growing woody species of plants. We have
decided to make charcoal from bamboo. Charcoal is a cleanly burning fuel and
much better than wood as a household fuel. We have developed a
stove-and-cooker system made totally out of stainless steel, and costing
just US$ 8. It uses just 100g charcoal to cook rice, beans (or meat) and a
vegetable for a family of 5.
We plan to harvest three year old bamboo culms, which allows one and two
year old culms to stand in the clump. In this way, the plantation is never
completely denuded of its vegetal cover. We have induced 100 farmers in the
vicinity of our research station to plant 100 bamboo seedlings each of
Dendrocalamus strictus. Under our climatic conditions it develops solid
culms without lumen. Our oven-and-retort system works beautifully for
making charcoal from this variety of bamboo. The retorts would be filled
with bamboo culms cut into suitable lengths to fit into the retorts. The
branches and leaves would be used for heating the retorts from outside, to
pyrolyse the bamboo culms enclosed in the retorts. The retorts are so
designed, that the pyrolysis gas is released below the retort, where it
burns to add to the process heat. Each farmer is expected to produce about
700 culms on an average. The kiln is portable. It would be taken to the
client's farm and operated there. Only the charcoal would be transported and
not the bamboo. I shall be grateful to receive any suggestions and tips from
readers.
Yours sincerely
Dr.A.D.Karve, President,
Appropriate Rural Technology Institute
Pune, India

From ventfory at IAFRICA.COM Tue Jun 24 08:16:28 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:26 2004
Subject: Fw: [ethos] 5 things
Message-ID: <TUE.24.JUN.2003.141628.0200.VENTFORY@IAFRICA.COM>

Dean you said

>Expert operation is required to achieve turndown and ease of use
>reinforces bigger and wasteful fires. Perhaps stoves can easily save
>firewood if they are efficient at delivering Low Power to the pot.

What about achieving a natural hassle- free turndown and Low Power burn?

With gasifying stoves I think it is possible to achieve a prolonged "Low Power" burn as part of the carbon burn phase (charcoal) following complete gasification, but only when using refractory ceramics, with their highly insulative properties. Such combustion chambers can maintain internal combustion temperatures, without a tall flame, for surprisingly long times, sufficient for pot simmering.

Look at my example: My initial fuel load recommendation to the users of my charcoal stove was 600 grams, to allow them at least 45 minutes of cooking on a "producer-gas".

They have however reduced the fuel load to as little as 100 grams, with little regard for the gas part of the burn, since adequate simmering temperatures are achieved for cooking a meal that takes 1 to 1.5 hours to cook, done almost entirely (70%?) on the carbon burn alone.

100g - 300g of charcoal used twice daily, normally for heating the house early in the morning and for cooking supper late in the afternoon has also meant incredible energy savings by way of reduced electricity (cooking), fuelwood (cooking) and paraffin (heating) usage.

Regards

Kobus
ventfory@iafrica.com

From kchisholm at CA.INTER.NET Tue Jun 24 11:01:56 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:26 2004
Subject: Charcoal from bamboo
Message-ID: <TUE.24.JUN.2003.120156.0300.KCHISHOLM@CA.INTER.NET>

Dear Dr. Karve

I am very impressed with your many good works and accomplishments.

Drying the bamboo cane to "the optimal" moisture content would ensure that
charcoal yield is maximized.

1: Do you know what the "optimal moisture content" is for bamboo that is to
be made into charcoal?

2: What is the moisture content of the bamboo as harvested?

3: Do you "pre-dry" it before feeding to the charcoal retorts, and if so,
how do you do this?

4: Would you have a graph showing "Charcoal Yield vs Moisture Content of
Bamboo Charged to Retorts?"

Kindest regards,

Kevin Chisholm

----- Original Message -----
From: "A.D. Karve" <adkarve@PN2.VSNL.NET.IN>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, June 24, 2003 12:26 AM
Subject: [STOVES] Charcoal from bamboo

> Bamboo is one of the fastest growing woody species of plants. We have
> decided to make charcoal from bamboo. Charcoal is a cleanly burning fuel
and
> much better than wood as a household fuel. We have developed a
> stove-and-cooker system made totally out of stainless steel, and costing
> just US$ 8. It uses just 100g charcoal to cook rice, beans (or meat) and a
> vegetable for a family of 5.
> We plan to harvest three year old bamboo culms, which allows one and two
> year old culms to stand in the clump. In this way, the plantation is never
> completely denuded of its vegetal cover. We have induced 100 farmers in
the
> vicinity of our research station to plant 100 bamboo seedlings each of
> Dendrocalamus strictus. Under our climatic conditions it develops solid
> culms without lumen. Our oven-and-retort system works beautifully for
> making charcoal from this variety of bamboo. The retorts would be filled
> with bamboo culms cut into suitable lengths to fit into the retorts. The
> branches and leaves would be used for heating the retorts from outside, to
> pyrolyse the bamboo culms enclosed in the retorts. The retorts are so
> designed, that the pyrolysis gas is released below the retort, where it
> burns to add to the process heat. Each farmer is expected to produce about
> 700 culms on an average. The kiln is portable. It would be taken to the
> client's farm and operated there. Only the charcoal would be transported
and
> not the bamboo. I shall be grateful to receive any suggestions and tips
from
> readers.
> Yours sincerely
> Dr.A.D.Karve, President,
> Appropriate Rural Technology Institute
> Pune, India

From tstubb at IHUG.CO.NZ Tue Jun 24 14:08:21 2003
From: tstubb at IHUG.CO.NZ (Thomas Stubbing)
Date: Tue Aug 10 18:30:26 2004
Subject: Charcoal from bamboo
Message-ID: <WED.25.JUN.2003.060821.1200.TSTUBB@IHUG.CO.NZ>

Dear Dr Karve,

Having a few years ago carbonised a sample of bamboo from Central America in a
small kiln employing clean combustion of the pyrolyss gases to help dry and
carbonise the load, I know that what you are planning works.

I also know that bamboo is possibly the world's fastest growing plant in terms
of adding dry weight per hectare per annum and that it's clumps, properly cared
for as you describe by leaving the younger culms, can survive almost
indefinately.

However, by continually harvesting the three year old culms the farmers will, I
think, gradually deplete the soil's minerals, so I would recommend that the ash
from your stove and cooker system and any other stoves used is returned to the
farmers to be returned to the soil around the clumps.

Aftre reading your message, I read Kevin Chisholm's response:

Drying the bamboo cane to "the optimal" moisture content would ensure
that
charcoal yield is maximized.

1: Do you know what the "optimal moisture content" is for bamboo that
is to
be made into charcoal?

2: What is the moisture content of the bamboo as harvested?

3: Do you "pre-dry" it before feeding to the charcoal retorts, and if
so,
how do you do this?

4: Would you have a graph showing "Charcoal Yield vs Moisture Content
of
Bamboo Charged to Retorts?"

In my view:

1. Pre-drying wouldn't significantly increase the charcoal yield per culm
because there is little shrinkage of the stems during drying, so the DRY
weight contained in the kiln would not increase substantially,
2. Pre-drying is labour-intensive and takes much longer at temperatures below
that at which the bamboo is carbonised in the kiln, and
3. The charcoal yield from DRY bamboo and other biomass carbonised in an
airtight retort is around 50% so, if for example the un-carbonised
material's initial moisture content is 33.3%, the result of carbonising
each 300 kg of it will be to release 100 kg of 'steam' and 100 kg of
pyrolysis gases, leaving 100 kg of charcoal.

I hope this helps.

Regards,

Thomas J Stubbing

"A.D. Karve" wrote:

> Bamboo is one of the fastest growing woody species of plants. We have
> decided to make charcoal from bamboo. Charcoal is a cleanly burning fuel and
> much better than wood as a household fuel. We have developed a
> stove-and-cooker system made totally out of stainless steel, and costing
> just US$ 8. It uses just 100g charcoal to cook rice, beans (or meat) and a
> vegetable for a family of 5.
> We plan to harvest three year old bamboo culms, which allows one and two
> year old culms to stand in the clump. In this way, the plantation is never
> completely denuded of its vegetal cover. We have induced 100 farmers in the
> vicinity of our research station to plant 100 bamboo seedlings each of
> Dendrocalamus strictus. Under our climatic conditions it develops solid
> culms without lumen. Our oven-and-retort system works beautifully for
> making charcoal from this variety of bamboo. The retorts would be filled
> with bamboo culms cut into suitable lengths to fit into the retorts. The
> branches and leaves would be used for heating the retorts from outside, to
> pyrolyse the bamboo culms enclosed in the retorts. The retorts are so
> designed, that the pyrolysis gas is released below the retort, where it
> burns to add to the process heat. Each farmer is expected to produce about
> 700 culms on an average. The kiln is portable. It would be taken to the
> client's farm and operated there. Only the charcoal would be transported and
> not the bamboo. I shall be grateful to receive any suggestions and tips from
> readers.
> Yours sincerely
> Dr.A.D.Karve, President,
> Appropriate Rural Technology Institute
> Pune, India

From rstanley at LEGACYFOUND.ORG Tue Jun 24 15:55:01 2003
From: rstanley at LEGACYFOUND.ORG (Richard Stanley)
Date: Tue Aug 10 18:30:26 2004
Subject: Charcoal from bamboo
Message-ID: <TUE.24.JUN.2003.225501.0300.>

Dear AD,

Thanks for the information about bamboo retorts and charoal making.

The stoves group falls into two camps it seems: One pro, charcoal making and
the other, pro the more efficent use of fuelwood directly. (I'm a bit outside
both camps). Aside from the other obvious benefits of your ingenious system of
retorting in the field , What is the comparison in heat loss versus heat gained
in charcoal making:
IE., How much do your gain in terms of total thermal energy of the charcoal
minus the heat lost in making it in your retort and how does this compare to
simply harvesting and burning the bamboo in the kitchen directly.

kind regards,

Richard Stanley
Kampala

"A.D. Karve" wrote:

> Bamboo is one of the fastest growing woody species of plants. We have
> decided to make charcoal from bamboo. Charcoal is a cleanly burning fuel and
> much better than wood as a household fuel. We have developed a
> stove-and-cooker system made totally out of stainless steel, and costing
> just US$ 8. It uses just 100g charcoal to cook rice, beans (or meat) and a
> vegetable for a family of 5.
> We plan to harvest three year old bamboo culms, which allows one and two
> year old culms to stand in the clump. In this way, the plantation is never
> completely denuded of its vegetal cover. We have induced 100 farmers in the
> vicinity of our research station to plant 100 bamboo seedlings each of
> Dendrocalamus strictus. Under our climatic conditions it develops solid
> culms without lumen. Our oven-and-retort system works beautifully for
> making charcoal from this variety of bamboo. The retorts would be filled
> with bamboo culms cut into suitable lengths to fit into the retorts. The
> branches and leaves would be used for heating the retorts from outside, to
> pyrolyse the bamboo culms enclosed in the retorts. The retorts are so
> designed, that the pyrolysis gas is released below the retort, where it
> burns to add to the process heat. Each farmer is expected to produce about
> 700 culms on an average. The kiln is portable. It would be taken to the
> client's farm and operated there. Only the charcoal would be transported and
> not the bamboo. I shall be grateful to receive any suggestions and tips from
> readers.
> Yours sincerely
> Dr.A.D.Karve, President,
> Appropriate Rural Technology Institute
> Pune, India

From kchisholm at CA.INTER.NET Tue Jun 24 14:52:18 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:26 2004
Subject: Charcoal from bamboo
Message-ID: <TUE.24.JUN.2003.155218.0300.KCHISHOLM@CA.INTER.NET>

Dear Thomas

----- Original Message -----
From: "Thomas Stubbing" <tstubb@IHUG.CO.NZ>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Tuesday, June 24, 2003 3:08 PM
Subject: Re: [STOVES] Charcoal from bamboo

Thanks for your helpful comments...

Del...>
> In my view:
>
> 1. Pre-drying wouldn't significantly increase the charcoal yield per
culm
> because there is little shrinkage of the stems during drying, so the
DRY
> weight contained in the kiln would not increase substantially,

My concern here is that moisture from the interior of the charge would react
with "already formed charcoal" on the outside of the charge, as per:
H2O + C ----> CO + H2

> 2. Pre-drying is labour-intensive and takes much longer at temperatures
below
> that at which the bamboo is carbonised in the kiln, and

Yes indeed. However, depending on climate conditions, it may be practical to
cut the bamboo, stack it, and let it air dry for a period of time.

> 3. The charcoal yield from DRY bamboo and other biomass carbonised in an
> airtight retort is around 50% so, if for example the un-carbonised
> material's initial moisture content is 33.3%, the result of
carbonising
> each 300 kg of it will be to release 100 kg of 'steam' and 100 kg of
> pyrolysis gases, leaving 100 kg of charcoal.

OK!! This could form the basis for a criteria to determine if pre-drying of
the bamboo is worthwhile or not.
>
> I hope this helps.
>
Yes indeed. With this information, Dr. Karve should be able to get some good
insights into the merits, or lack thereof, of pre-drying the bamboo.

Kindest regards,

Kevin Chisholm

From adkarve at PN2.VSNL.NET.IN Wed Jun 25 00:18:03 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:26 2004
Subject: high and low fire in wood burning stoves
Message-ID: <WED.25.JUN.2003.094803.0530.ADKARVE@PN2.VSNL.NET.IN>

The National Programme on Improved Cookstoves, organised by the Ministry of
Non-Conventional Energy Sources, Government of India, was terminated by the
ministry in the year 2002 after almost 20 years of implementation, because
it failed to achieve the expected success. We have been asking housewives
why they did not like the improved cookstoves that were being propagated
under this programme. One of the reasons for their not wanting these stoves
was that the new cookstoves cooked too slowly. In rural areas, it is
generally the practice that the housewife starts cooking flat unleavened
bread, called bhakri, early in the morning. The bhakri, which looks like the
mexican tortilla, is made of sorghum, pearl millet or finger millet, and it
is at least 4 to 5 mm thick. An intense fire is needed for roasting the
bhakri through and through. The bhakri serves the family as breakfast and
it is also taken to work as packed lunch. In a typical household of about 5
to 6 people, the housewife has to bake at least 20 to 24 such bhakris. They
are baked one after another. So she needs a big fire in her stove
continuously for about an hour and half.
The National Programme on Improved Cookstoves was conducted as a
multilocational programme through a number of local units called the
Technical Backup Support Units, which developed the cookstoves according to
the regional requirements. But in order to obtain some uniformity, the
norms regarding the efficiency and emissions were prescribed by the Ministry
and a uniform set of tests was also prescribed to monitor these parameters.
In the case of efficiency, it was the boiling and evaporation test. It was
also prescribed that this test be conducted at a burning rate of about 1 kg
wood per hour. As a result, the cookstoves that got evolved under this
programme performed quite well when one adhered to the prescribed burning
rate of fuel, but in actual practice, the housewives burned fuel at a higher
rate. Because the firebox of the improved cookstoves was designed to accept
only a few sticks at a time, the stove choked when it was stuffed with more
wood than optimum. As a result the fire intensity was much less than desired
and it also produced a lot of smoke. It was very frustrating and irritating
for the housewife to have the whole family shouting at her for the bhakris,
and she not being able to produce them as fast as they ate. After a couple
of days of trial and error, she ultimately removes the improved cookstove
and starts using her older cookstove.
LPG has become very popular, wherever it was introduced, not only because it
has a blue and non-polluting flame, but also because of its intense heat and
the finger-tip control of the fire intensity. Biogas represents a very
similar technology, but it is useful only to families having at least 6 to 8
heads of cattle. In addition, its fermenter is also extremely bulky, the
minimum size being 2 cubic meters. Such an apparatus has to be installed
outdoors, because the kitchen just does not have enough space to accommodate
it. In villages, the houses are built so close to each other, that there is
no space for the biogas plant. As a result, in spite of the technology
being vigorously promoted by The Ministry of Non-conventional Energy
Sources, there exist only about 2 million biogas plants in India. Even
operating the biogas plant is not very user friendly. The housewife has to
feed it daily with about 100 litres of dung slurry and she has to dispose
off the same quantity of effluent. This is heavy physical labour and the
housewife often deliberately sabotages the biogas plant in order to avoid
this extra chore. A survey showed that out of the 2 million biogas plants
that were constructed in India during the past 20 years, as many as 1.6
million biogas plants were out of order, and not in use.
I have developed a highly compact biogas plant, having a volume of just
400 litres. It operates on waste starch (spoilt grain, nonedible seed of
various species, oilcake of non-edible oilseeds, rhizomes of banana, canna,
nutgrass, arums, flour swept from the floor of a flour mill etc.) and
produces about 800 litres of gas from just 1 kg starch. It produces daily
just 5 litres of effluent, which can just be thrown at the base of any tree,
or applied to the vegetable bed in the backyard. The retention time of dung
in the dung-based biogas fermenter is 6 weeks, while that of starch is only
6 hours, which is why the volume of the fermenter could be reduced. The
biogas produced from starch has about 60% methane by weight, while that
produced from cattle dung has only 25% methane by weight. As a result, even
the 800 litres produced by my biogas plant is enough for cooking the meal of
a family.
We are trying to commercialise this new biogas fermenter. It costs only
US$30 as against US$250 for the conventional biogas fermenter.
Yours A.D.Karve
-----Original Message-----
From: Dean Still <dstill@epud.net>
To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
Date: Tuesday, June 24, 2003 11:33 AM
Subject: [STOVES] Fw: [ethos] 5 things

>>The Five Things I Thought About After The ETHOS Testing and Design Seminar
>>(Please Comment!!)
>>
>>1.) The standard VITA water boiling test may not accurately predict how
>much
>>fuel is used for cooking because A.) Simmering is a longer process (60 to
>>120 minutes for beans) than bringing the pot to initial boiling (15
>minutes)
>>but the time difference is not accounted for in the test. B.) More
>>importantly, the water-boiling test credits steam produced in the
simmering
>>phase but excess steam is not penalized. Water at a rolling boil produces
>>much more steam than water at 100C, which is not at a rolling boil. In a
>>simple experiment, I put one cup of water in two equal sized pots on a gas
>>stove. I used full power to bring each to a rolling boil. One pot was left
>>at a rolling boil at full power but the other was held at 100C at a
greatly
>>reduced and more fuel-efficient power. When all water had evaporated from
>>the rolling boil pot, 5/8th of the water remained in the simmering pot. A
>>stove with good turn down would make much less steam which is good for
fuel
>>efficient cooking but bad for scoring high on the WBT.
>>2.) I think that Prasad and Sangen in ?Technical Aspects of Wood Burning
>>Cookstoves? (1983) were more accurate by stressing the importance of
>>efficiency at simmering. They measuring high power initially as a separate
>>timed criteria. But in their view, high power performance is mostly
>>important for pleasing cooks with rapid boiling times. As they explain,
>fuel
>>efficiency in a cook stove is more heavily dependent on efficiency of low
>>power operation. They show how supposedly inefficient stoves with good
turn
>>down can use less wood in cooking tests. Page 215. Rob Bailis, Adriana
>>Valencia and I had a similar impression when the Jiko used half again as
>>much wood as the Rocket in cooking lentils although the scores on the WBT
>>were close.
>>3.) The Three Stone Fire scores very high in our tests. This result only
>>extends a semi buried tradition of the open fire doing well in the WBT.
The
>>open fire was presumed to be very inefficient by early stove designers.
But
>>scores of more careful researchers, like Grant Ballard-Tremeer, Tami Bond,
>>Emma George, Sam Baldwin, etc, report the three stone fire as doing better
>>than many stoves in the WBT. I believe that the possible error in the WBT,
>>rewarding not penalizing excess production of steam in the simmering phase
>>and exaggerating the importance of the high power phase, artificially
>>inflates the open fire scores. I believe that Prasad and Sangen are closer
>>to predicting fuel efficiency in cooking by highlighting good turn down
and
>>simmering performance in their version of the WBT. If we look at the Time
>>Under Curve results (suggested by Dr. Alan Berick), and compare with
scores
>>on the WBT, faults in our WBT equations seem apparent to me.
>>4.) I believe that a stove that can simmer efficiently like Lanny?s stove,
>>which scored an amazing 6,000 seconds in Time Under Curve, will be most
>>efficient in cooking food, especially foods that simmer for a long time. A
>>great stove would be able to both efficiently produce high power to boil
>>quickly and efficiently turn down power so that heat lost from the pot is
>>replaced without generating excess steam i.e., too much heat. Is this
about
>>10 to 1 turn down?
>>5.) It seems reasonable to imagine that many stoves with great turn down
>may
>>save firewood even if they are imperfect in other respects. The only real
>>defect in the open fire is that it goes out easily when sticks are
>>withdrawn. Expert operation is required to achieve turndown and ease of
use
>>reinforces bigger and wasteful fires. Perhaps stoves can easily save
>>firewood if they are efficient at delivering Low Power to the pot.
>>
>>
>>
>

From adkarve at PN2.VSNL.NET.IN Tue Jun 24 22:33:06 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:26 2004
Subject: Charcoal from bamboo
Message-ID: <WED.25.JUN.2003.080306.0530.ADKARVE@PN2.VSNL.NET.IN>

Generally, the charred material is about one third by weight of the original
plant biomass. But since we also burn some biomass outside the retorts to
start the process of pyrolysis, the total char yield is about 20% of the
starting weight of the total biomass. The calorific value of the char
should theoretically be about 8000 kcal/kg, but is generally lower due to
non-combustible components like silicon, calcium, potassium etc. In the case
of sugarcane leaves, the calorific value of our briquettes is about 4500
kcal/kg, the same as wood. We have not yet determined the calorific value of
bamboo char.
The main advantage of charcoal is that it is a cleanly burning fuel. With a
wood fire, it is necessary to have a chimney, which not only adds to the
cost of the cookstove but also requires frequent cleaning. In India, one of
the reasons for the failure of the National Programme on Improved Cookstoves
was that housewives did not want a stove with a chimney.
I give below a short description of the charcoaling process developed by us
for sugarcane leaves.
Yours A.D.Karve
Briquetted charcoal from sugarcane trash

Appropriate Rural Technology Institute,

Maninee Apartments, Survey no. 13, Dhayarigaon, Pune 411 041, India.

INTRODUCTION

Dry leaves, left in the field after harvest of sugarcane, are called trash.
On an average, a hectare of sugarcane generates about 10 tonnes of trash.
Because it has no value as cattle fodder, and because it also resists
decomposition, the trash is burnt in situ, in order to clear the field for
the next crop. It is estimated, that in the State of Maharashtra, more than
4000,000 tonnes of trash are destroyed in this way. Pyrolysing the trash and
converting it into fuel briquettes, can be a very profitable, small scale,
rural business.

THE PROCESS

The charring kiln, a portable cylindrical structure (about 150 cm wide and
100 cm tall) made out of sheet iron, is placed in the field, where sugarcane
harvest is in progress. The trash is filled into cylindrical metal
containers, 37.5 cm wide and 60 cm tall. The kiln takes 7 such containers at
a time. All containers together accommodate 21 kg of trash. After loading
the containers into the kiln, the top of the kiln is closed with sheet metal
lid, which is provided with a chimney. About 10 kg trash is burnt underneath
the containers (in the kiln) to start the process of pyrolysis. The heat of
the trash burning underneath the containers pyrolyses the trash in the
containers. Pyrolysis gas generated in the process leaves the containers
through holes in their bottom, and it too burns, to serve as additional fuel
in this process. Each batch, taking about 40 minutes to complete, produces
about 7 kg char (30% of the trash filled in the barrels) Working with two
sets of barrels, and completing 8 batches in a working shift of 8 hours, a
couple of workers can produce about 50 kg char per day. The cha is powdered,
mixed with a suitable binder, and shaped, with the help of a mold, into
briquettes. The briquettes are laid out in the sun for drying.

ECONOMIC CONSIDERATIONS

The operator must have some land for drying the briquettes. The capital cost
of the kiln and the set of 21containers is about Rs. 13,000 (US $ 270). It
is recommended that the menfolk of a family produce the char while the
womenfolk make the briquettes. Thus a family unit of 4 or 5 persons can
produce daily 50 kg briquettes, which can be sold at a price of Rs.5 per kg.
A family can thus earn daily Rs. 250 (US$5) per day, which is equivalent to
the income of an urban middle class family. Use can be made of other
agricultural wastes such as stems of cotton, stalks of wheat, rice,
pigeonpea, safflower, castor, maize cobs, or leaf litter from any plantation
crop like rubber, cashew, mango, papaya, etc. If the 16 weeks of the rainy
(monsoon) season are excluded, such a unit can work for about 36 weeks in a
year, earning more than Rs. 60,000. (US$ 1200).

-----Original Message-----
From: Richard Stanley <rstanley@legacyfound.org>
To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
Date: Wednesday, June 25, 2003 1:43 AM
Subject: Re: [STOVES] Charcoal from bamboo

>Dear AD,
>
>Thanks for the information about bamboo retorts and charoal making.
>
>The stoves group falls into two camps it seems: One pro, charcoal making
and
>the other, pro the more efficent use of fuelwood directly. (I'm a bit
outside
>both camps). Aside from the other obvious benefits of your ingenious system
of
>retorting in the field , What is the comparison in heat loss versus heat
gained
>in charcoal making:
>IE., How much do your gain in terms of total thermal energy of the charcoal
>minus the heat lost in making it in your retort and how does this compare
to
>simply harvesting and burning the bamboo in the kitchen directly.
>
>kind regards,
>
>Richard Stanley
>Kampala
>
>
>"A.D. Karve" wrote:
>
>> Bamboo is one of the fastest growing woody species of plants. We have
>> decided to make charcoal from bamboo. Charcoal is a cleanly burning fuel
and
>> much better than wood as a household fuel. We have developed a
>> stove-and-cooker system made totally out of stainless steel, and costing
>> just US$ 8. It uses just 100g charcoal to cook rice, beans (or meat) and
a
>> vegetable for a family of 5.
>> We plan to harvest three year old bamboo culms, which allows one and two
>> year old culms to stand in the clump. In this way, the plantation is
never
>> completely denuded of its vegetal cover. We have induced 100 farmers in
the
>> vicinity of our research station to plant 100 bamboo seedlings each of
>> Dendrocalamus strictus. Under our climatic conditions it develops solid
>> culms without lumen. Our oven-and-retort system works beautifully for
>> making charcoal from this variety of bamboo. The retorts would be filled
>> with bamboo culms cut into suitable lengths to fit into the retorts. The
>> branches and leaves would be used for heating the retorts from outside,
to
>> pyrolyse the bamboo culms enclosed in the retorts. The retorts are so
>> designed, that the pyrolysis gas is released below the retort, where it
>> burns to add to the process heat. Each farmer is expected to produce
about
>> 700 culms on an average. The kiln is portable. It would be taken to the
>> client's farm and operated there. Only the charcoal would be transported
and
>> not the bamboo. I shall be grateful to receive any suggestions and tips
from
>> readers.
>> Yours sincerely
>> Dr.A.D.Karve, President,
>> Appropriate Rural Technology Institute
>> Pune, India
>

From adkarve at PN2.VSNL.NET.IN Tue Jun 24 22:24:10 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:26 2004
Subject: charcoal from bamboo
Message-ID: <WED.25.JUN.2003.075410.0530.ADKARVE@PN2.VSNL.NET.IN>

We intend to air dry the bamboo culms and I expect them to have about 10% moisture. In some of the initial trials with bamboo, we could get about 40 to 45% charcoal when compared to the air dried material that went into the retorts. However, taking into consideration the material that is burned outside the retorts, the total char yield would be much less. We shall of course load the bamboo stalks into the retorts and burn the branches outside the retorts.
Yours A.D.Karve

From crispin at NEWDAWN.SZ Wed Jun 25 05:24:25 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:26 2004
Subject: 5 things from Kobus
Message-ID: <WED.25.JUN.2003.112425.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

I agree pretty much with Kobus so I won't repeat those parts.

Kobus wrote:
>With gasifying stoves I think it is possible to achieve
>a prolonged "Low Power" burn as part of the carbon
>burn phase (charcoal) following complete gasification,
>but only when using refractory ceramics, with their highly
>insulative properties.

There is another option and I hope people are not wedded to the theory part
of the ceramic chamber without at least considering other, as yet largely
undiscussed, theories. I am refering to gas insulation using the incoming
air as the insulator.

Air is a very good insulator and can serve the same purpose as the cermaic
parts much of the time. The combustion chamber can be metal provided that
it is gas cooled (by the incoming air) so the life is increased.

A perforated metal combustion chamber provides preheating of the air at very
low cost and is, in practice, much easier to commercalize because it is
light and strong and easy to fabricate in quantity.

As the challenge of making a very small fire boils down to keeping it hot
and combusting well, it is difficult for me to see achieving this 'in the
open'. The fire will have to be contained, and if the primary air is
pre-heated, it can burn 'to the last drop' of fuel. Or the last nugget, if
you will.

Any stove that does not have pre-heated primary air will, near the end of
the fuel, simply go out because the incoming air will chill the fuel below
its ignition point. There will always be unburned charcoal lumps, typically
more than 100 gms if fuelled with wood and fed cold air. On damp winter
days it can be worse.

Another point which refers more to ADK's charcoal bamboo: if the charcoal
could be produced in a stove and burned immediately after its being
produced, then the maximum efficiency can be obtained. Making charcoal in
one place and letting it cool to be relighted in another place is less
efficient then burning the whole fuel in a single go, whether or not it is
made in a charcoal-producing stove or a retort. Charcoal is not cleaner
than wood: it is a stove comparison that must be made. Both wood and
charcoal are burned in any wood fire. Not enough effort is being made to
make clear-burning wood stoves because, in my view, charcoal has a cleaner
reputation. Well, charcoal usually produces a lot of CO. If the response
is that stoves can be made to burn that CO, I respond that wood can also be
made to burn very well. I have proof, as do many others.

The stove that can produce charcoal by gassifying the wood, followed by
burning the charcoal, while doing so in an enclosed space with pre-heated
primary air solves all the problems simultaneously: single device conversion
to heat, low initial fuel load, complete burning of fuel, low emissions,
controllability, low distribution cost, regional fabrication, mass marketing
potential through commercial outlets.

Sincerely
Crispin

From snkm at BTL.NET Wed Jun 25 09:03:31 2003
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:26 2004
Subject: 5 things from Kobus
Message-ID: <WED.25.JUN.2003.070331.0600.SNKM@BTL.NET>

Dear Stovers;

>Air is a very good insulator and can serve the same purpose as the cermaic
>parts much of the time. The combustion chamber can be metal provided that
>it is gas cooled (by the incoming air) so the life is increased.

I have built such a stove using scrap washing machine parts -- steel cement
reinforcing rod -- and a part of a metal drum.

The purpose is to boil 20 gallons of cane juice.

It works extremely well -- fuel is bagasse -- coconut husks -- coconut
shells -- or wood.

If I get a chance I'll take pictures and mount them.

I came to the conclusion that "air" is the best refractory -- it works
extremely well.

You'll all chuckle when you see pictures.

The stove is stable combustion no matter how strong the wind. Like a
hurricane lamp -- if you will.

Oh -- the steel cement rod is cut to short parts -- welded together to make
the fire-box which sits in center -- surrounded by "air".

>Any stove that does not have pre-heated primary air will, near the end of
>the fuel, simply go out because the incoming air will chill the fuel below
>its ignition point. There will always be unburned charcoal lumps, typically
>more than 100 gms if fuelled with wood and fed cold air. On damp winter
>days it can be worse.

This stove has an air feed directly under the steel burning cage -- and
only the finest ash is left.

This is an easy design for anyone to build. Further -- the entire stove
breaks down to parts easily.

Peter Singfield

Belize

At 11:24 AM 6/25/2003 +0200, Crispin wrote:
>Dear Stovers
>
>I agree pretty much with Kobus so I won't repeat those parts.
>
>Kobus wrote:
>>With gasifying stoves I think it is possible to achieve
>>a prolonged "Low Power" burn as part of the carbon
>>burn phase (charcoal) following complete gasification,
>>but only when using refractory ceramics, with their highly
>>insulative properties.
>
>There is another option and I hope people are not wedded to the theory part
>of the ceramic chamber without at least considering other, as yet largely
>undiscussed, theories. I am refering to gas insulation using the incoming
>air as the insulator.
>
>Air is a very good insulator and can serve the same purpose as the cermaic
>parts much of the time. The combustion chamber can be metal provided that
>it is gas cooled (by the incoming air) so the life is increased.
>
>A perforated metal combustion chamber provides preheating of the air at very
>low cost and is, in practice, much easier to commercalize because it is
>light and strong and easy to fabricate in quantity.
>
>As the challenge of making a very small fire boils down to keeping it hot
>and combusting well, it is difficult for me to see achieving this 'in the
>open'. The fire will have to be contained, and if the primary air is
>pre-heated, it can burn 'to the last drop' of fuel. Or the last nugget, if
>you will.
>
>Any stove that does not have pre-heated primary air will, near the end of
>the fuel, simply go out because the incoming air will chill the fuel below
>its ignition point. There will always be unburned charcoal lumps, typically
>more than 100 gms if fuelled with wood and fed cold air. On damp winter
>days it can be worse.
>
>Another point which refers more to ADK's charcoal bamboo: if the charcoal
>could be produced in a stove and burned immediately after its being
>produced, then the maximum efficiency can be obtained. Making charcoal in
>one place and letting it cool to be relighted in another place is less
>efficient then burning the whole fuel in a single go, whether or not it is
>made in a charcoal-producing stove or a retort. Charcoal is not cleaner
>than wood: it is a stove comparison that must be made. Both wood and
>charcoal are burned in any wood fire. Not enough effort is being made to
>make clear-burning wood stoves because, in my view, charcoal has a cleaner
>reputation. Well, charcoal usually produces a lot of CO. If the response
>is that stoves can be made to burn that CO, I respond that wood can also be
>made to burn very well. I have proof, as do many others.
>
>The stove that can produce charcoal by gassifying the wood, followed by
>burning the charcoal, while doing so in an enclosed space with pre-heated
>primary air solves all the problems simultaneously: single device conversion
>to heat, low initial fuel load, complete burning of fuel, low emissions,
>controllability, low distribution cost, regional fabrication, mass marketing
>potential through commercial outlets.
>
>Sincerely
>Crispin
>

From crispin at NEWDAWN.SZ Mon Jun 23 08:53:15 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:26 2004
Subject: Vesto emission data from Germany
Message-ID: <MON.23.JUN.2003.145315.0200.CRISPIN@NEWDAWN.SZ>

Dear Stovers

I am not sure exactly how this was done in terms of the fuel type, stage of the burn, or methods but I fearlessly report them anyway:

VESTO
CO in ppm
CO2 volume %
O2 in volume %
Soot figure at the rim of the pot [PIC's?]
Temperature

in ?C

At the flame in the combustion chamber
130

391

1011
5,6

8,7

12,8
15,2

12

8,1
3-4
350

553

277

At the side of the pot directly at the base of the pot
781
3,1
17,7
3-4
261

At the height of the pot
195
2,0
18,9
3-4
n.a.

20 cm above the pot
74
0,3
20,6
3-4
55

40 cm above the pot
184
0,2
20,7
3-4
32

These figures are, in my opinion, significantly different from those from the ProBEC lab in Harare. As I know nothing about how either of them did the tests I can only read them and hope other info comes from other sources.

Regards
Crispin

From rmiranda at INET.COM.BR Wed Jun 25 15:48:12 2003
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:30:26 2004
Subject: [ethos] peruvian stoves
In-Reply-To: <NGBBKDEHILILFNJPHEFIAEOPCOAA.ronallarson@qwest.net>
Message-ID: <WED.25.JUN.2003.164812.0300.RMIRANDA@INET.COM.BR>

Ron: I just came from Peru early June for a conference in Trujillo.
Unfortunately I did not came across anyone doing stoves, but I am aware of
people at Piura University involvement few years ago. Where in peru are you
going?

rogerio

At 09:04 a.m. 18/06/03 -0600, Ron Larson wrote:
>Tom, Lisa, Stuart, Ethos, stoves:
>
> 1. Re photographs - I also appreciate these. Great additions to
> Tom's
>files. One question I have is on the height of the cooking and wood-entry
>surfaces. Any standards developing (as in the US- where all are same, I
>think, at? It is nice to be able
>
> It looks pretty likely that I will take a trip to Peru in late
> July-early
>August. Anyone able to supply any stoves contacts there?
>
> I'm especially hoping that Lisa can make some contacts at her
> meeting in
>Mexico that I can follow up with.
>
>Ron
>
> >-----Original Message-----
> >From: owner-ethos@vrac.iastate.edu
> >[mailto:owner-ethos@vrac.iastate.edu]On Behalf Of Tom Miles
> >Sent: Tuesday, June 17, 2003 8:39 PM
> >To: Stuart Conway; ethos; Lisa Buttner
> >Subject: Re: [ethos] [Fwd: stove photos]
> >
> >
> >Stuart,
> >
> >I'm sure there are many stories behind each of the pictures and the 5800
> >stoves tat you mentioned. (Does that include Pat Manley's 1000 stoves?)
> >
> >I don't have time to put the pictures and their stories up on the Cocinas y
> >Estufas Mejoradas website
> >http://www.repp.org/discussiongroups/resources/estufas/ before the Mexico
> >conference but I look forward to seeing the stories in Spanish so that we
> >can include them along with the reports of the stove performance from your
> >surveys.
> >
> >I also hope that Lisa will direct people to the Cocinas y Estufas site and
> >to the bioenergia and stoves email lists so that we can generate some
> >discussion to help support dissemination in Mexico, Central and South
> >America.
> >
> >Saludos,
> >
> >Tom
> >
> >----- Original Message -----
> >From: "Stuart Conway" <stuart@treeswaterpeople.org>
> >To: "ethos" <ethos@vrac.iastate.edu>; "Lisa Buttner" <LButtner@winrock.org>
> >Sent: Tuesday, June 17, 2003 4:56 PM
> >Subject: [ethos] [Fwd: stove photos]
> >
> >
> >> Lisa,
> >>
> >> Here are some more photos for the conference in Mexico, including some
> >> that Jeremy Foster took in Michoacan. Larry Winiarski and Jeremy built
> >> some Justa stoves to demonstrate them for GIRA.
> >>
> >> Stuart
> >>
> >
> >
> >
> >

From rmiranda at INET.COM.BR Wed Jun 25 17:52:08 2003
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:30:26 2004
Subject: PROLENA honoured in Ashden Awards 2003
In-Reply-To: <005101c33674$fe7e1d50$6501a8c0@OFFICE3>
Message-ID: <WED.25.JUN.2003.185208.0300.RMIRANDA@INET.COM.BR>

Tom: Thanks a lot. It was a good reward for all these years of hard
working. rogerio

At 08:10 a.m. 19/06/03 -0700, Tom Miles wrote:
>Following is Grant's report on t he Ashden Awards 2003.
>
>Congratulations Prolena.
>
>Thanks to Grant and to Ron Larson for making Stovers aware of the award.
>
>Tom Miles
>
>----- Original Message -----
>From: "Grant Ballard-Tremeer" <grant@ecoharmony.com>
>Sent: Thursday, June 19, 2003 7:07 AM
>Subject: [hedon] HEDON member PROLENA honoured in Ashden Awards 2003
>
>
> > The award ceremony for the 2003 Ashden Awards was held on 18 June 2003
> > in London. A total of 6 finalists from developing countries under the
> > categories of 'Food Security', 'Enterprise' and 'Community Welfare'
> > were recognised for their outstanding and innovative renewable energy
> > projects.
> >
> > For full details see http://www.hedon.info/news.php?op=view&rowid=62
> >
> > Congratulations to Rog?rio Carneiro de Miranda, representing the NGO
> > PROLE?A in Nicaragua, an active HEDON member, who was awarded the
> > runner-up prize in the 'Food security' category. The PROLE?A project
> > works to produce and promoting fuel-efficient stoves for small
> > household tortilla businesses.
> >
> > The winner in the food security category was the Energy and Research
> > Training Centre in Eritrea. The centre works with local women to
> > produce and distribute smokeless, fuel efficient clay stoves which
> > reduce firewood collection time whilst creating cleaner, healthier
> > living and working environments. The Award will be used to train 900
> > women to make stoves, each of whom will train a further 10 women in
> > their village to do the same.
> >
> > Details of the other award winners, and links to the Ashden Awards
> > webpage may be found on the HEDON Household Energy Network webpage at:
> >
> > http://www.hedon.info/news.php?op=view&rowid=62
> >
> > The HEDON Household Energy Network was instrumental in bringing the
> > awards to the attention of a large number of those that applied and
> > for assisting a number of small organisations in developing countries
> > to make their applications.
> >
> > --
> > Grant Ballard-Tremeer PhD, visit Eco on the web at http://ecoharmony.com
> > HEDON Household Energy Network http://hedon.info
> > SPARKNET Knowledge Network in Southern and East Africa
>http://sparknet.info
> > -------------------

From hseaver at CYBERSHAMANIX.COM Wed Jun 25 22:57:55 2003
From: hseaver at CYBERSHAMANIX.COM (Harmon Seaver)
Date: Tue Aug 10 18:30:26 2004
Subject: Sugar to Hydrogen?
Message-ID: <WED.25.JUN.2003.215755.0500.HSEAVER@CYBERSHAMANIX.COM>

Spent last weekend at the Midwest Renewable Energy Fair -- the
largest event of it's kind. Totally awesome. I went last year for two
days, this year I just camped there for the whole 3 day affair, wish
they'd make it a week long. Anyway, one of the seminars was on this new
process for making H2. Seems pretty promising.

http://www.virent.com/technology.htm

--
Harmon Seaver
CyberShamanix
http://www.cybershamanix.com

From dstill at EPUD.NET Thu Jun 26 01:28:20 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:27 2004
Subject: THE EFFECT OF A CHIMNEY ON INDOOR LEVELS OF CO
Message-ID: <WED.25.JUN.2003.222820.0700.DSTILL@EPUD.NET>

Dear Stovers:

Today at the Aprovecho lab we tested a Rocket stove with chimney to see if
the chimney would adequately lower the levels of carbon dioxide in our 8' by
8' by 8' testing chamber. The residence time of air in the room is 19
minutes, indicating approximately three air exchanges per hour. At the
recent ETHOS Stove Testing and Design Seminar, Dr. Tami Bond and Dr. Dale
Andreatta tested three stoves without chimneys in the same chamber using a
higher and lower HOBO Carbon Monoxide data logger. The results were:

Vesto Stove
.Lower HOBO 4ppm
higher HOBO 510ppm
Vesto Stove
.Lower HOBO 16ppm
.higher HOBO 550ppm
Jiko Stove
.Lower HOBO 80ppm
higher HOBO 320ppm
Rocket Stove
Lower HOBO 13ppm
higher HOBO 140ppm

Today the same Rocket stove was fitted with a 4" in diameter 8" long metal
chimney that exited through the ceiling of the test chamber. Three tests
were run of the stove using 400 grams of wood for each test which averaged
about 40 minutes per burn.

Carbon Monoxide levels in the test chamber never rose above six parts per
million with an average of 3.5 parts per million for the three tests.

Using a simple chimney decreases CO levels quite drastically. If the stove
does not leak harmful emissions are removed from the indoor environment.

Best,

Dean Still
Aprovecho Research Center

From crispin at NEWDAWN.SZ Thu Jun 26 03:53:29 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:27 2004
Subject: THE EFFECT OF A CHIMNEY ON INDOOR LEVELS OF CO
Message-ID: <THU.26.JUN.2003.095329.0200.CRISPIN@NEWDAWN.SZ>

Dear Dean

That was pretty impressive. I do think you mean an 8 foot chimney, right?

You guys have a nice facility!

Regards
Envious Crispin

----- Original Message -----
From: "Dean Still" <dstill@epud.net>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, June 26, 2003 7:28 AM
Subject: [STOVES] THE EFFECT OF A CHIMNEY ON INDOOR LEVELS OF CO

Dear Stovers:

Today at the Aprovecho lab we tested a Rocket stove with chimney to see if
the chimney would adequately lower the levels of carbon dioxide in our 8' by
8' by 8' testing chamber. The residence time of air in the room is 19
minutes, indicating approximately three air exchanges per hour. At the
recent ETHOS Stove Testing and Design Seminar, Dr. Tami Bond and Dr. Dale
Andreatta tested three stoves without chimneys in the same chamber using a
higher and lower HOBO Carbon Monoxide data logger. The results were:

Vesto Stove..Lower HOBO 4ppm.higher HOBO 510ppm
Vesto Stove..Lower HOBO 16ppm..higher HOBO 550ppm
Jiko Stove..Lower HOBO 80ppm.higher HOBO 320ppm
Rocket Stove.Lower HOBO 13ppm.higher HOBO 140ppm

Today the same Rocket stove was fitted with a 4" in diameter 8" long metal
chimney that exited through the ceiling of the test chamber. Three tests
were run of the stove using 400 grams of wood for each test which averaged
about 40 minutes per burn.

Carbon Monoxide levels in the test chamber never rose above six parts per
million with an average of 3.5 parts per million for the three tests.

Using a simple chimney decreases CO levels quite drastically. If the stove
does not leak harmful emissions are removed from the indoor environment.

Best,

Dean Still
Aprovecho Research Center

From snkm at BTL.NET Thu Jun 26 08:51:37 2003
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:27 2004
Subject: [GASL] Sugar to Hydrogen?
Message-ID: <THU.26.JUN.2003.065137.0600.SNKM@BTL.NET>

At 09:57 PM 6/25/2003 -0500, Harmon Seaver wrote:
> Spent last weekend at the Midwest Renewable Energy Fair -- the
>largest event of it's kind. Totally awesome. I went last year for two
>days, this year I just camped there for the whole 3 day affair, wish
>they'd make it a week long. Anyway, one of the seminars was on this new
>process for making H2. Seems pretty promising.
>
>
>http://www.virent.com/technology.htm
>
>
>--
>Harmon Seaver
>CyberShamanix
>http://www.cybershamanix.com

Dear Listers;

Below is the clip from that page. Not much hard info there at all.

But this line:

"via the liquid-phase reforming of biomass-derived compounds such as sugars
and sugar alcohols."

Sounds like the high pressure super critical water process. With addition
of a catalyst processing.

You remember?? The one I have been harping on for the past many years.

HYDROGEN PRODUCTION FROM HIGH-MOISTURE CONTENT BIOMASS IN
SUPERCRITICAL WATER

University of Hawaii

***********************

It is very suitable for micro-scale production of H2 or methane. Very
efficient -- and very ignored by this mail list!!

Well -- time always tells -- we wait -- and we watch -- observers only --
no "doers" here.

With minimal resources I could have constructed a micro unit to do this
years ago!

Well, back to my micro-cane crusher -- setting up to produce lots of cane
juice -- but not for gasifying. For producing a local wine called "Chee-Cha"

How easy it would be to process cane juice to methane in a super critical
water reactor -- burning the bagasse as the heat energy for this
endothermic reaction.

All on a micro -- rsingle 3rd world house -- level.

Well -- one day -- maybe --

Peter Singfield
Belize

********appended********

The ACR Process

Virent Energy Systems is developing a new catalytic process that allows the
generation of either hydrogen rich fuel gas or medium to high-energy
density hydrocarbon fuel gas (20 to 34 MJ/Nm3) via the liquid-phase
reforming of biomass-derived compounds such as sugars and sugar alcohols.
The ACR process was discovered at the University of Wisconsin-Madison
Chemical Engineering Department in 2001 by Dr. Randy Cortright and
Professor James Dumesic. The process has the following characteristics and
advantages:

Liquid-Phase Reforming - The ACR process generates gas without the need to
volatilize water, which represents a major energy savings compared to
conventional gasification or anaerobic digestion. This exothermic process
generates its own processing energy when producing hydrocarbons, and over
85% of the sugar’s thermal energy is retained in the product fuel gas.
Furthermore, the ACR process requires only a simple two-phase separator to
remove the product gases - this also requires very little energy.

Low-Temperature Processing - The ACR process is most efficient at
temperatures where the water-gas shift reaction is also favorable for low
CO concentrations. Undesirable decomposition reactions typically
encountered when carbohydrates are heated are minimized at the low
temperature of the ACR process. Finally, the ACR process could also
utilize low-temperature waste heat as processing energy. (Process heat
equivalent to approximately 25 percent of hydrogen production stream will
be required if pure hydrogen is produced.)

Carbohydrate Feedstocks - The heterogeneous catalysts utilized in the ACR
process are expected to be effective for processing any water-soluble sugar
or sugar alcohol, regardless of carbon number and stereoisomer.
Accordingly, this process is expected to be able to produce fuel from a
single sugar, mixture of sugars, and oligomers of sugars. Finally, this
process is not adversely affected by furans and acetic acid that may be
found in some carbohydrate streams as a result of the extraction processes
utilized to remove the carbohydrates from biomass.

From Carl.Carley at EML.ERICSSON.SE Thu Jun 26 09:14:00 2003
From: Carl.Carley at EML.ERICSSON.SE (Carl Carley (EMP))
Date: Tue Aug 10 18:30:27 2004
Subject: [GASL] Sugar to Hydrogen?
Message-ID: <THU.26.JUN.2003.151400.0200.CARL.CARLEY@EML.ERICSSON.SE>

Peter,
Sounds like you're on the wrong list, check out wastewatts@yahoogroups.com, loads of 'doers' there

carl

-----Original Message-----
From: Peter Singfield [mailto:snkm@BTL.NET]
Sent: 26 June 2003 13:52
To: STOVES@LISTSERV.REPP.ORG
Subject: Re: [STOVES] [GASL] Sugar to Hydrogen?

At 09:57 PM 6/25/2003 -0500, Harmon Seaver wrote:
> Spent last weekend at the Midwest Renewable Energy Fair -- the
>largest event of it's kind. Totally awesome. I went last year for two
>days, this year I just camped there for the whole 3 day affair, wish
>they'd make it a week long. Anyway, one of the seminars was on this new
>process for making H2. Seems pretty promising.
>
>
>http://www.virent.com/technology.htm
>
>
>--
>Harmon Seaver
>CyberShamanix
>http://www.cybershamanix.com

Dear Listers;

Below is the clip from that page. Not much hard info there at all.

But this line:

"via the liquid-phase reforming of biomass-derived compounds such as sugars and sugar alcohols."

Sounds like the high pressure super critical water process. With addition of a catalyst processing.

You remember?? The one I have been harping on for the past many years.

HYDROGEN PRODUCTION FROM HIGH-MOISTURE CONTENT BIOMASS IN SUPERCRITICAL WATER

University of Hawaii

***********************

It is very suitable for micro-scale production of H2 or methane. Very efficient -- and very ignored by this mail list!!

Well -- time always tells -- we wait -- and we watch -- observers only -- no "doers" here.

With minimal resources I could have constructed a micro unit to do this years ago!

Well, back to my micro-cane crusher -- setting up to produce lots of cane juice -- but not for gasifying. For producing a local wine called "Chee-Cha"

How easy it would be to process cane juice to methane in a super critical water reactor -- burning the bagasse as the heat energy for this endothermic reaction.

All on a micro -- rsingle 3rd world house -- level.

Well -- one day -- maybe --

Peter Singfield
Belize

********appended********

The ACR Process

Virent Energy Systems is developing a new catalytic process that allows the generation of either hydrogen rich fuel gas or medium to high-energy density hydrocarbon fuel gas (20 to 34 MJ/Nm3) via the liquid-phase reforming of biomass-derived compounds such as sugars and sugar alcohols. The ACR process was discovered at the University of Wisconsin-Madison Chemical Engineering Department in 2001 by Dr. Randy Cortright and Professor James Dumesic. The process has the following characteristics and
advantages:

Liquid-Phase Reforming - The ACR process generates gas without the need to volatilize water, which represents a major energy savings compared to conventional gasification or anaerobic digestion. This exothermic process generates its own processing energy when producing hydrocarbons, and over 85% of the sugar's thermal energy is retained in the product fuel gas. Furthermore, the ACR process requires only a simple two-phase separator to remove the product gases - this also requires very little energy.

Low-Temperature Processing - The ACR process is most efficient at temperatures where the water-gas shift reaction is also favorable for low CO concentrations. Undesirable decomposition reactions typically encountered when carbohydrates are heated are minimized at the low temperature of the ACR process. Finally, the ACR process could also utilize low-temperature waste heat as processing energy. (Process heat equivalent to approximately 25 percent of hydrogen production stream will be required if pure hydrogen is produced.)

Carbohydrate Feedstocks - The heterogeneous catalysts utilized in the ACR process are expected to be effective for processing any water-soluble sugar or sugar alcohol, regardless of carbon number and stereoisomer. Accordingly, this process is expected to be able to produce fuel from a single sugar, mixture of sugars, and oligomers of sugars. Finally, this process is not adversely affected by furans and acetic acid that may be found in some carbohydrate streams as a result of the extraction processes utilized to remove the carbohydrates from biomass.

From snkm at BTL.NET Thu Jun 26 10:45:09 2003
From: snkm at BTL.NET (Peter Singfield)
Date: Tue Aug 10 18:30:27 2004
Subject: [GASL] Sugar to Hydrogen?
Message-ID: <THU.26.JUN.2003.084509.0600.SNKM@BTL.NET>

Carl -- your right!!

Have moved further discussion over to the Gas list "only" --

Most of the people on this list that might have interest are already there.

And yes -- putting a chimney on a stove is a good idea. Congrats all for
this deep perception!

Peter

At 03:14 PM 6/26/2003 +0200, Carl Carley (EMP) wrote:
>Peter,
>Sounds like you're on the wrong list, check out
wastewatts@yahoogroups.com, loads of 'doers' there
>
>carl
>
>-----Original Message-----
>From: Peter Singfield [mailto:snkm@BTL.NET]
>Sent: 26 June 2003 13:52
>To: STOVES@LISTSERV.REPP.ORG
>Subject: Re: [STOVES] [GASL] Sugar to Hydrogen?
>
>
>At 09:57 PM 6/25/2003 -0500, Harmon Seaver wrote:
>> Spent last weekend at the Midwest Renewable Energy Fair -- the
>>largest event of it's kind. Totally awesome. I went last year for two
>>days, this year I just camped there for the whole 3 day affair, wish
>>they'd make it a week long. Anyway, one of the seminars was on this new
>>process for making H2. Seems pretty promising.
>>
>>
>>http://www.virent.com/technology.htm
>>
>>
>>--
>>Harmon Seaver
>>CyberShamanix
>>http://www.cybershamanix.com
>
>Dear Listers;
>
>Below is the clip from that page. Not much hard info there at all.
>
>But this line:
>
>"via the liquid-phase reforming of biomass-derived compounds such as
sugars and sugar alcohols."
>
>Sounds like the high pressure super critical water process. With addition
of a catalyst processing.
>
>You remember?? The one I have been harping on for the past many years.
>
>HYDROGEN PRODUCTION FROM HIGH-MOISTURE CONTENT BIOMASS IN SUPERCRITICAL WATER
>
>University of Hawaii
>
>***********************
>
>It is very suitable for micro-scale production of H2 or methane. Very
efficient -- and very ignored by this mail list!!
>
>Well -- time always tells -- we wait -- and we watch -- observers only --
no "doers" here.
>
>With minimal resources I could have constructed a micro unit to do this
years ago!
>
>Well, back to my micro-cane crusher -- setting up to produce lots of cane
juice -- but not for gasifying. For producing a local wine called "Chee-Cha"
>
>How easy it would be to process cane juice to methane in a super critical
water reactor -- burning the bagasse as the heat energy for this
endothermic reaction.
>
>All on a micro -- rsingle 3rd world house -- level.
>
>Well -- one day -- maybe --
>
>Peter Singfield
>Belize
>
>
>********appended********
>
>The ACR Process
>
>Virent Energy Systems is developing a new catalytic process that allows
the generation of either hydrogen rich fuel gas or medium to high-energy
density hydrocarbon fuel gas (20 to 34 MJ/Nm3) via the liquid-phase
reforming of biomass-derived compounds such as sugars and sugar alcohols.
The ACR process was discovered at the University of Wisconsin-Madison
Chemical Engineering Department in 2001 by Dr. Randy Cortright and
Professor James Dumesic. The process has the following characteristics and
>advantages:
>
>Liquid-Phase Reforming - The ACR process generates gas without the need to
volatilize water, which represents a major energy savings compared to
conventional gasification or anaerobic digestion. This exothermic process
generates its own processing energy when producing hydrocarbons, and over
85% of the sugar's thermal energy is retained in the product fuel gas.
Furthermore, the ACR process requires only a simple two-phase separator to
remove the product gases - this also requires very little energy.
>
>
>Low-Temperature Processing - The ACR process is most efficient at
temperatures where the water-gas shift reaction is also favorable for low
CO concentrations. Undesirable decomposition reactions typically
encountered when carbohydrates are heated are minimized at the low
temperature of the ACR process. Finally, the ACR process could also
utilize low-temperature waste heat as processing energy. (Process heat
equivalent to approximately 25 percent of hydrogen production stream will
be required if pure hydrogen is produced.)
>
>
>Carbohydrate Feedstocks - The heterogeneous catalysts utilized in the ACR
process are expected to be effective for processing any water-soluble sugar
or sugar alcohol, regardless of carbon number and stereoisomer.
Accordingly, this process is expected to be able to produce fuel from a
single sugar, mixture of sugars, and oligomers of sugars. Finally, this
process is not adversely affected by furans and acetic acid that may be
found in some carbohydrate streams as a result of the extraction processes
utilized to remove the carbohydrates from biomass.
>

From dstill at EPUD.NET Thu Jun 26 20:05:04 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:27 2004
Subject: adding a chimney to a $5 cooking stove
Message-ID: <THU.26.JUN.2003.170504.0700.DSTILL@EPUD.NET>

.Dear Stovers,

So hard to type!... The cooking stove, made for ProBec, GTZ in South Africa,
was fitted with a 4" in diameter eight foot high metal chimney that exited
through the ceiling of the test chamber. The chimney lowered indoor CO
emissions to an average of 3.5 ppm.

The chimney was NOT eight inches long....

Great that a simple solution to indoor air pollution, the chimney, lowers
Carbon Monoxide levels so well...

Best,

Dean
Aprovecho
www.efn.org/~apro

From jmdavies at XSINET.CO.ZA Thu Jun 26 04:13:42 2003
From: jmdavies at XSINET.CO.ZA (John Davies)
Date: Tue Aug 10 18:30:27 2004
Subject: Heat Insulation
Message-ID: <THU.26.JUN.2003.101342.0200.JMDAVIES@XSINET.CO.ZA>

Crispin wrote,

> There is another option and I hope people are not wedded to the theory
part
> of the ceramic chamber without at least considering other, as yet largely
> undiscussed, theories. I am refering to gas insulation using the incoming
> air as the insulator.
>
> Air is a very good insulator and can serve the same purpose as the cermaic
> parts much of the time. The combustion chamber can be metal provided that
> it is gas cooled (by the incoming air) so the life is increased.
>

Greetings all,

Time to add my few cents worth.

Air is the best insulator known. All refractory material has a much greater
heat conductivity than any gas.,
but is used in order to trap small air pockets, to avoid the hot air from
migrating, and losing heat via the convection of the air. So the best
refractory composition would have a mass approaching zero, with the maximum
number of sealed air cells.

Crispin refers to using the incoming air as an insulator. Not strictly true,
what it is doing is to cool the metal and recycle the heat back to the
combustion area. The fact is that it does work, and promotes a layer of cool
fuel against the metal where a densely packed fuel bed is used.

Happy Stoving,
John Davies.

From rdboyt at YAHOO.COM Thu Jun 26 22:35:36 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:27 2004
Subject: Practical Tips For Potters Making Improved Cooking Stoves--
Forward and Introduction
Message-ID: <THU.26.JUN.2003.193536.0700.RDBOYT@YAHOO.COM>

Stovers all:

I have just received the booklet "Practical Tips for
Pottery Making; Improved Cooking Stoves- A Manual for
Potters and Stove Promoters", prepared by Tim Jones,
illustrated by Debbie Riviere, and published by Hofman
Systems Engineering b.v. PO Box 6423100 AP Schiedam,
The Netherlands (Nov 1993). It was graciously sent to
me by Auke Koopmans who wrote the foreword, in which
he states "There are no restrictions as to the use of
this book, as long as the text and illustrations are
not reproduced in any form for profitable gain." In
the forward, Dr. Koopmans writes "Improved cooking
stoves designed to make food preparation more fuel
efficient are now available... around the world."

"The most commonly used material for the construction
of all or part of stoves is fired clay, also called
pottery or ceramics. This is because it is a
low-cost, easily molded material that is available in
most parts of the world.

"Improved cooking stoves are not produced in highly
sophisticated pottery factories, but in small
workshops. The materials are normally not carefully
selected and refined, but comprised of what is
available locally. The production equipment is not
expensive machinery, but skilled labor, involving
techniques that have been passed down for generations.

"This booklet provides information on clay selection,
production methods, handy tips, etc., concerning the
production of fired clay cooking stoves. These tips
have been tried and tested in many countries. Because
of the considerable variations in the minerals that
make up local clays, there is no clay mixture recipe
or production method that guarantees crack-free
cooking stoves. A considerable amount of trial and
error is, and will remain, involved before the best
possible clay mixtures and production processes are
determined.

"The tests and production methods included in this
booklet have been chosen for their practicality. They
will provide a guide toward achieving the best results
from whatever is available. They cannot be used on
their own but will, combined with an already existing
knowledge of pottery, help avoid the most common
problems associated with improved cooking stove
production."

My reactions to the above quotations from the booklet
"Tips For Potters" are:
1) My own experiences with ceramics are decidedly
provincial when compared with the world-wide scope of
the observations found in the booklet.
2) My series on ceramics for stoves is aimed at
stovers both with and without previous experience with
ceramics. Your feedback would help confirm whether or
not I am hitting that mark.

The next submission of condensations from this booklet
will cover "Finding and Selecting Clay." It is
intended as a supplement to the ongoing series
"Ceramics for Stoves." Comments, suggestions,
criticisms, encouragements, and ideas will be welcome.

Dick Boyt

__________________________________
Do you Yahoo!?
SBC Yahoo! DSL - Now only $29.95 per month!
http://sbc.yahoo.com

From crispin at NEWDAWN.SZ Fri Jun 27 03:30:34 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:27 2004
Subject: adding a chimney to a $5 cooking stove - Dean
Message-ID: <FRI.27.JUN.2003.093034.0200.CRISPIN@NEWDAWN.SZ>

Thanks Dean.

Do you think a 3 inch chimney will work just as well? There is a big
different in price and getting a steel part to fit the 3 inch one is also
easier. 76mm is a standard fence pole size.

Thanks
Crispin

----- Original Message -----
From: "Dean Still" <dstill@epud.net>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Friday, June 27, 2003 2:05 AM
Subject: [STOVES] adding a chimney to a $5 cooking stove

.Dear Stovers,

So hard to type!... The cooking stove, made for ProBec, GTZ in South Africa,
was fitted with a 4" in diameter eight foot high metal chimney that exited
through the ceiling of the test chamber. The chimney lowered indoor CO
emissions to an average of 3.5 ppm.

The chimney was NOT eight inches long....

Great that a simple solution to indoor air pollution, the chimney, lowers
Carbon Monoxide levels so well...

Best,

Dean
Aprovecho
www.efn.org/~apro

From crispin at NEWDAWN.SZ Fri Jun 27 03:18:56 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:27 2004
Subject: Heat Insulation - John
Message-ID: <FRI.27.JUN.2003.091856.0200.CRISPIN@NEWDAWN.SZ>

Dear John

I agree with your 'strictly. What I was saying was supposd to mean the the
'effect' is that of an insulator.

Seeing as air is free and ceramic material is not, there is a certain logic
in using it for a cheap stove.

People have reported here that Rocket stoves have a problem using steel as
the chamber and that stainless steel, 3 series, was tried but that this too
burned through in a few months.

I agree with your comment that the cooling / insulating air recycling the
heat keeps the metal temperatures down, hopefully enough to greatly extend
the metal's life.

I know it seems to be a contradiction, but I keep nattering about how it is
important to get the incoming air temperatures up, while at the same times
saying that the metal temperatures must be kept down, however there is a
sense of scale involve that should be highlighted. If the metal temps can
be reduced to 400-500 and the air temps increased to 300-400 C, then it
appears that we have the best of both worlds.

If a vortex can be maintained in the centre of a rising column so most of
the heat production is going on, in effect in the middle of a tube made
entirely of air, then the 'outside' of the tube of air, which lies between
the burning vortex and the metal combustion chamber, insulates the metal
considerably.

This condition is quite easy to obtain, actually. One of the reasons people
appear to go for ceramics is to be able to have very hot flames next to the
walls and prevent the walls from deteriorating while maintaining a high
combustion pemperature. Fair enough. But it seems to be a lot of trouble
to go to if the problem can be avoided in the first place by spinning the
combustion.

I am going to try another grate aimed at achieving this, optimized for
charcoal.

Regards
Crispin
----- Original Message -----
From: "John Davies" <jmdavies@XSINET.CO.ZA>
To: <STOVES@LISTSERV.REPP.ORG>
Sent: Thursday, June 26, 2003 10:13 AM
Subject: [STOVES] Heat Insulation

Crispin wrote,

> There is another option and I hope people are not wedded to the theory
part
> of the ceramic chamber without at least considering other, as yet largely
> undiscussed, theories. I am refering to gas insulation using the incoming
> air as the insulator.
>
> Air is a very good insulator and can serve the same purpose as the cermaic
> parts much of the time. The combustion chamber can be metal provided that
> it is gas cooled (by the incoming air) so the life is increased.
>

Greetings all,

Time to add my few cents worth.

Air is the best insulator known. All refractory material has a much greater
heat conductivity than any gas.,
but is used in order to trap small air pockets, to avoid the hot air from
migrating, and losing heat via the convection of the air. So the best
refractory composition would have a mass approaching zero, with the maximum
number of sealed air cells.

Crispin refers to using the incoming air as an insulator. Not strictly true,
what it is doing is to cool the metal and recycle the heat back to the
combustion area. The fact is that it does work, and promotes a layer of cool
fuel against the metal where a densely packed fuel bed is used.

Happy Stoving,
John Davies.

From elk at WANANCHI.COM Fri Jun 27 06:14:33 2003
From: elk at WANANCHI.COM (elk)
Date: Tue Aug 10 18:30:27 2004
Subject: KCJ operating temps
Message-ID: <FRI.27.JUN.2003.131433.0300.ELK@WANANCHI.COM>

Stovers- some fuel for the ongoing insulation discussions:

The KCJ is a very popular 'improved' stove- a sheet-metal skinned open-top,
single pot, slightly hour-glass shaped charcoal burner that typically
carries between 700 to 1000 gm fuel. The upper half holds a fired-clay
insert with about ten 2 cm dia holes through to the lower ash-collecting
chamber. Lighting and power control is via an approx 6 X 9 cm hinged door
into the lower uninsulated chamber.

I've measured the Jiko temps while fully lit (30 min after ignition) burning
1 kg typical hardwood charcoal with a alu pot containing 2 litres boiling
water approx 4cm
above coals. I used a temperature probe that gave a digital readout (Rueger,
'Model K thermometer').

boiling water (immersion): 94 C (at 1800 m. asl)- indicates an acceptable
low-temp thermometer calibration.
Centre of coals (stove set at 'high power'- no probe contact: 813 C
1 cm from pot bottom above coals- no contact: 606 C
between coals & side, contacting inside of ceramic liner: 505 C
outside skin temp upper top contact temp: 165 C
inside lower ashbox (no contact) w. door open 148 C
outside skin temp lower ashbox w. door open (contact) 53 C
outside skin temp lower ashbox w. door closed for 4 min.- low power
(contact) 96 C

Seems to be some room for insulative improvements!

rgds;
elk

 

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

From ventfory at IAFRICA.COM Fri Jun 27 10:06:14 2003
From: ventfory at IAFRICA.COM (Kobus)
Date: Tue Aug 10 18:30:27 2004
Subject: Fw: KCJ operating temps
Message-ID: <FRI.27.JUN.2003.160614.0200.VENTFORY@IAFRICA.COM>

Stovers and Elsen,

regarding Elsen's observations:

[Elk]"The KCJ is a very popular 'improved' stove- a sheet-metal skinned open-top,
single pot, slightly hour-glass shaped charcoal burner that typically carries between 700 to 1000 gm fuel. "

A Photo of the KCJ can be seen at (thanks to Tom M):

http://www.rff.org/~ezzati/stoves.html
Go to the last photo below the inscription:

"Improved" stoves are made of a ceramic liner (seen below for Upesi and Lira) and a metal body (seen below for KCJ), connected with a mixture of vermiculite and cement

[Kv]Elsen:

Thanks for those measurements, I will refer and compare them to my findings, once I get my own testing equipment, hopefully quite soon.

How and where do you ignite the KCJ stove and have you made any observations regarding the high and low power phases the fuel load undergoes or any other observations that you could share with us?

And at what time defined point does the heat from the charcoal start to fade off to levels below 700?C and gradually lower that would be considered ineffective for pot simmering purposes.

Regards

Kobus

From rmiranda at INET.COM.BR Fri Jun 27 09:53:47 2003
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:30:27 2004
Subject: adding a chimney to a $5 cooking stove - Dean
In-Reply-To: <006701c33c7e$64c231a0$2a47fea9@md>
Message-ID: <FRI.27.JUN.2003.105347.0300.RMIRANDA@INET.COM.BR>

Crispin and Dean: we are a using a 3.5 inches chimney x 2.4 meters tall,
made of galvanized steel (26) which cost us in Nicaragua to produce US$ 6.7
, including the hat and the insert adapter to the stove.

rogerio

At 09:30 a.m. 27/06/03 +0200, Crispin wrote:
>Thanks Dean.
>
>Do you think a 3 inch chimney will work just as well? There is a big
>different in price and getting a steel part to fit the 3 inch one is also
>easier. 76mm is a standard fence pole size.
>
>Thanks
>Crispin
>
>
>----- Original Message -----
>From: "Dean Still" <dstill@epud.net>
>To: <STOVES@LISTSERV.REPP.ORG>
>Sent: Friday, June 27, 2003 2:05 AM
>Subject: [STOVES] adding a chimney to a $5 cooking stove
>
>
>.Dear Stovers,
>
>So hard to type!... The cooking stove, made for ProBec, GTZ in South Africa,
>was fitted with a 4" in diameter eight foot high metal chimney that exited
>through the ceiling of the test chamber. The chimney lowered indoor CO
>emissions to an average of 3.5 ppm.
>
>The chimney was NOT eight inches long....
>
>Great that a simple solution to indoor air pollution, the chimney, lowers
>Carbon Monoxide levels so well...
>
>Best,
>
>Dean
>Aprovecho
>www.efn.org/~apro

From adkarve at PN2.VSNL.NET.IN Thu Jun 26 20:20:59 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:27 2004
Subject: high and low fire in wood burning stoves
Message-ID: <FRI.27.JUN.2003.055059.0530.ADKARVE@PN2.VSNL.NET.IN>

Dear Dean,
Villagers generally have mud stoves having two pot-holes, giving more heat
at the
first hole and less at the second. The pothole giving more heat is used for
making bhakri (which is roasted) and the one giving lower heat is used for
simmering food that is to be cooked.
As far as the biogas fermenter is concerned, it is a small version of the
standard moving dome biogas plant, a very simple contraption
consisting of two drums, telescoping into one another. the outer drum is
open at the top and the inner one is open at its bottom. The outer drum is
filled with the material to be fermented and the inner drum is lowered into
it. A tap at the top of the inner drum is kept open while lowering the drum
into the outer one, and when it has been completely inserted into the outer
drum, the tap is closed. The gas accumulates in the inner drum which gets
lifted up due to increased buoyancy. (If a girl falls accidentally into
water, she should not remove her dress because the air caught in the dress
acts like a buoy :-))The inner drum is provided with a tap at the top,
through which the biogas can be led to the burner. Both the drums have a
capacity of approximately 200 litres.
A.D.Karve
-----Original Message-----
From: Dean Still <dstill@epud.net>
To: A.D. Karve <adkarve@PN2.VSNL.NET.IN>
Date: Thursday, June 26, 2003 11:08 AM
Subject: Re: [STOVES] high and low fire in wood burning stoves

>Dear Dr. Karve,
>
>As you pointed out previously stove designers need to listen to the cook
>before designing the stove. If women need to cook in a certain way, the
>stove needs to be an improvement for them, making their considerable daily
>chores easier not more difficult!
>
>In Mexico and Central America, cooks also make flat breads, tortillas, over
>a very hot flame. The stove needs to be able to produce this high power but
>if the stove cannot turn down sufficiently I am afraid that instead of
>efficiently simmering food only a rolling boil can be achieved which is
>wasteful of fuel.
>
>Do you have plans for the starch biogas fermenter? I would love to build
one
>here at Aprovecho.
>
>Best,
>
>Dean
>
>
>

From yark at U.WASHINGTON.EDU Fri Jun 27 17:18:17 2003
From: yark at U.WASHINGTON.EDU (Tami Bond)
Date: Tue Aug 10 18:30:27 2004
Subject: adding a chimney to a $5 cooking stove
In-Reply-To: <002201c33c3f$cac7be00$ea1e6c0c@default>
Message-ID: <FRI.27.JUN.2003.141817.0700.YARK@U.WASHINGTON.EDU>

Dean, & others,

> ...a 4" in diameter eight foot high metal chimney that exited through
> the ceiling of the test chamber. The chimney lowered indoor CO emissions
> to an average of 3.5 ppm. ... Great that a simple solution to indoor air
> pollution, the chimney, lowers Carbon Monoxide levels so well...

The chimney/no chimney discussion has woven throughout STOVES and ETHOS
debates throughout the years. I'd be interested in hearing a directed
discussion on this topic. (I am cc'ing ETHOS in the hopes that Laurie
Childers picks this up.)

I think it would be informative to include a chimney FAQ on the
stoves-REPP site. What are the advantages (removal of pollutants from
living space, better draft) and disadvantages (cost, durability)? Are
there case studies of situations where chimneys were and were not
successful? What's the oldest chimney stove out there?

Paul Anderson mentioned someone's comment that 'everything we need to know
about stoves is known'. If so, then it does need to be collected, right?
:-)

Tami

From adkarve at PN2.VSNL.NET.IN Sat Jun 28 02:52:48 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:27 2004
Subject: chimney
Message-ID: <SAT.28.JUN.2003.122248.0530.ADKARVE@PN2.VSNL.NET.IN>

Another reason for the failure of the improved cookstoves programme in India was the insistance of the Ministry of Non-conventional Soruces that all cookstoves must have a chimney. The recommended chimney was an asbestos-cement pipe, having an internal diameter of 4 inches and length of 10 feet. The cookstove worked satisfactorily for about 3 months, after which the chimney choked. The lack of draft and blockage of an outlet for smoke caused more smoke inside the kitchen than the traditional cookstove. The housewife was shown, at the time of installation of the cookstove, how to clean the chimney, but somebody had to climb on the roof for this chore. Being a tropical country, India does not have the professional chimneysweeps as in Northern Europe. The menfolk of the household considered this to be the responsibility of the housewife, and the housewife is generally physically fit to climb up on the roof of the house to clean the chimney. As a result the chimney never got cleaned and the housewife just stopped using the improved stove.
I relate this to warn others, who want to introduce a chimney in their programmes.
Yours A.D.Karve
We are now installing improved cookstoves based on charcoal or on biogas, and they do not need a chimney. As a result, there is great demand for our cooking devices as also for our fuels.

From kchisholm at CA.INTER.NET Sat Jun 28 07:20:53 2003
From: kchisholm at CA.INTER.NET (Kevin Chisholm)
Date: Tue Aug 10 18:30:27 2004
Subject: chimney
Message-ID: <SAT.28.JUN.2003.082053.0300.KCHISHOLM@CA.INTER.NET>

Dear Dr. Karve

The incident you describe sounds like a classic Bureaucratic Mess. The
Scenario usually goes something as follows:

"An arrogant bunch of Do-Good Bureaucrats in "head office" decide how things
are to be done. They never go to "The Field" to see the range conditions
under which the stove must operate, and to determine what the user wants the
stove to do. They don't look at the range of fuels available in various
local circumstances. They don't consider gender issues. They find out why
the present methods of cooking are employed, and what would be necessary in
a so-called " improved system" for the end users to consider it an improved
system.

They then order the stove people to come up with a solution. The stove
people come up with a solution that looks good on paper and works well in
the Lab.

The Bureaucrats stage a showing of the Stove with Chimney for their
Minister, using standardized fuels in a lab setting, and have 3 PhD's and 2
Lab Coated Technologists running the stove until the Minister goes back to
his office. Then they get a Grant approved for their next Lab Project, and
turn the stove over to "others" to install in the field. Their Project is
considered a success because it worked very well in the Lab with 3 PhD's and
2 Lab Coated Technologists. Indeed, the stove worked so well in the Lab,
that it can be sent immediately to the Field.

There is obviously no need for a Field Test Program, user training, or
follow-up on the stove. This money would be better spent doing more work in
the Lab. Additionally, nobody in the Ministry want to work in the Field,
because it is not a very nice place to work.

When the "improved" stove fails, it is not the fault of the people in The
Ministry, because the stove worked there. Clearly, the fault lies with the
people who were responsible for distributing the stove system to the end
users. But then, the Distributors report back to the Ministry that the End
User is "resistant to change" and does not want to operate the stove the way
it was used in the Lab. "

Now, isn't that a rather good formula to ensure that projects fail?
Everybody looks good, except for the End User who is blamed for project
failure.

Abandonment of the "chimney stove" because it plugs up is proof of a poorly
executed project. Some questions that should be addressed are:

"Why was the stove system so poorly designed that unburned combustibles are
allowed to escape"

"Why was the smoke and tar problem not discovered at the Lab Stage?"

"Why were there not provisions made for occasional cleaning of the chimney?"

"Why were Gender Issues not considered?"

"What would have happened to indoor air quality parameters if the "improved
stove" was fed fuel of a quality that was fed to the charcoal stove?"

Etc., etc, etc.

If I tried to sell a stove in Canada that vented the products of combustion
into the living space, I would be hit with enormous lawsuits, if I wasn't
shot by the Families of the victims before the Case came to Trial. I can't
see why it is any less unacceptable to subject poor people in third world
Countries to the ravages of an inside vented stove.

Kevin

 

Subject: [STOVES] chimney

Another reason for the failure of the improved cookstoves programme in India
was the insistance of the Ministry of Non-conventional Soruces that all
cookstoves must have a chimney. The recommended chimney was an
asbestos-cement pipe, having an internal diameter of 4 inches and length of
10 feet. The cookstove worked satisfactorily for about 3 months, after which
the chimney choked. The lack of draft and blockage of an outlet for smoke
caused more smoke inside the kitchen than the traditional cookstove. The
housewife was shown, at the time of installation of the cookstove, how to
clean the chimney, but somebody had to climb on the roof for this chore.
Being a tropical country, India does not have the professional chimneysweeps
as in Northern Europe. The menfolk of the household considered this to be
the responsibility of the housewife, and the housewife is generally
physically fit to climb up on the roof of the house to clean the chimney. As
a result the chimney never got cleaned and the housewife just stopped using
the improved stove.
I relate this to warn others, who want to introduce a chimney in their
programmes.
Yours A.D.Karve
We are now installing improved cookstoves based on charcoal or on biogas,
and they do not need a chimney. As a result, there is great demand for our
cooking devices as also for our fuels.

From jmdavies at XSINET.CO.ZA Sat Jun 28 05:56:25 2003
From: jmdavies at XSINET.CO.ZA (John Davies)
Date: Tue Aug 10 18:30:27 2004
Subject: Heat Insulation - John - further discussion.
Message-ID: <SAT.28.JUN.2003.115625.0200.JMDAVIES@XSINET.CO.ZA>

Greetings all,
Some further discussion.

Crispin wrote, ( content reduced )
> I agree with your 'strictly. What I was saying was supposd to mean the
the
> 'effect' is that of an insulator.

Quite right, the emphasis is on "effect".

> Seeing as air is free and ceramic material is not, there is a certain
logic
> in using it for a cheap stove.
>
> I agree with your comment that the cooling / insulating air recycling the
> heat keeps the metal temperatures down, hopefully enough to greatly extend
> the metal's life.
>
> If a vortex can be maintained in the centre of a rising column so most of
> the heat production is going on, in effect in the middle of a tube made
> entirely of air, then the 'outside' of the tube of air, which lies between
> the burning vortex and the metal combustion chamber, insulates the metal
> considerably.

But what is really happening here? Heat is still traveling to the wall by
radiation, which is cooled by the moving air layer. We have a problem here !

1 The air layer reduces the radiation to the metal, but reduces the
temperature of gasses reaching the pot,

2 this air cone does not react with the flame as the vortex conditions
produce largely laminar flow ( parallel flows with little mixing, causing
large excess air in the system. As I understand it approximately 100%
excess air is needed in the flame to to achieve total combustion, with a
light smoke haze produced with 30% excess, resulting in about 85%
combustion. So we are talking of 100% plus excess air. I think this
explains why the maximum efficiencies obtained with clean combustion are
about 25%.

So we sit with a compromise of material cost vs stove efficiency.
Personally, I prefer the "air insulation effect",
It would appear that there is a long way to go to reach the ideal situation.

Keep up the good work,

John Davies

From jmdavies at XSINET.CO.ZA Sat Jun 28 06:15:16 2003
From: jmdavies at XSINET.CO.ZA (John Davies)
Date: Tue Aug 10 18:30:27 2004
Subject: Stove chimneys
Message-ID: <SAT.28.JUN.2003.121516.0200.JMDAVIES@XSINET.CO.ZA>

Greetings,

The sizing of a chimney is an exact science requiring complicated
computations and outside the scope of practice of most of us, who use the
empirical route to develop our stove systems.

This brings one to the question. Has anybody come up with a simple formula
to change the chimney effect with predictable results ?

This can be divided into 2 areas. The effect of the chimney diameter, and
that of the height. I feel sure that there must be a correlation, within
certain limits, which will give the result of changes to the parameters on
an existing system.

Another item that comes to mind, is the effect of a horizontal section in
the chimney. Once again I come to the conclusion that an extra height of X
times the horizontal length will be needed.

Any ideas ?

John Davies.

From adkarve at PN2.VSNL.NET.IN Sat Jun 28 09:07:24 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:27 2004
Subject: chimney
Message-ID: <SAT.28.JUN.2003.183724.0530.ADKARVE@PN2.VSNL.NET.IN>

The fuel that is normally used in rural India is certainly not high grade
fuelwood. It consists of stalks of cotton, pigeonpea (Cajanus cajans), corn
shanks, dung cakes and the like. It is not even completely dry when the
housewife uses it. It produces a lot of tar and smoke. The method that is
advocated to clean the chimney is to run a cloth bag full of sand up and
down the chimney. It is able to remove the soot but not the tar that sticks
to the sides of the chimney and keeps accumulating. The traditional Indian
rural domestic cookstoves do not have a grate. We tried to produce
chimneyless stoves, that were provided with a grate, but because of the high
ash content of the low grade fuel, the space below the grate gets filled up
with ash and reduces the air supply to the fuel. These are the practical
problems faced in the field. As I stated in my previous communication, the
solution that we have adopted is to use charcoal or biogas, both of which
burn more cleanly than wood and neither requires a chimney. Charcoal is made
from agrowaste, such as sugarcane leaves, wheat straw, cotton stalks etc.
and it is briquetted. This technology has given rise to a cottage industry
in our part of the world and it is slowly spreading. The biogas made from
waste starch faced certain practical problems but they are being removed.
Processed fuels appears to be the key to solving the problem of indoor air
pollution caused by biomass burning stoves. We are currently testing a
chimneyless gasifier stove made by a talented researcher named Punchibunda
in Srilanka. This stove requires wood to be cut into small pieces. We are
investigating if this stove can be operated using cotton and pigeonpea
stalks cut into small pieces. If this stove accepts this material, then
providing housewives with pieces of these stalks could also become a cottage
industry.
Use of agrowaste as fuel is frowned upon by the soil scientists, because
biomass that would normally be used as soil amendment is now being burnt. I
asked all the soil scientists who were willing to talk to me, what the
biomass did to the soil. They all told me that it served as food for soil
microbes. My argument is that the highly signified and silicified
agrowaste is too tough for the soil micro-organisms to digest. So instead of
applying tonnes of such undigestible stuff to the soil, could be we apply
something that would be easier for the soil microbes to digest? The fact
that green manure raises the soil fertility to a greater extent than
farmyard manure, may be due to the higher digestibility of the green manure.
Any comments or suggestions?
A.D.Karve
-----Original Message-----
From: Kevin Chisholm <kchisholm@ca.inter.net>
To: A.D. Karve <adkarve@PN2.VSNL.NET.IN>; STOVES@LISTSERV.REPP.ORG
<STOVES@LISTSERV.REPP.ORG>
Date: Saturday, June 28, 2003 4:53 PM
Subject: Re: [STOVES] chimney

>Dear Dr. Karve
>
>The incident you describe sounds like a classic Bureaucratic Mess. The
>Scenario usually goes something as follows:
>
>"An arrogant bunch of Do-Good Bureaucrats in "head office" decide how
things
>are to be done. They never go to "The Field" to see the range conditions
>under which the stove must operate, and to determine what the user wants
the
>stove to do. They don't look at the range of fuels available in various
>local circumstances. They don't consider gender issues. They find out why
>the present methods of cooking are employed, and what would be necessary in
>a so-called " improved system" for the end users to consider it an improved
>system.
>
>They then order the stove people to come up with a solution. The stove
>people come up with a solution that looks good on paper and works well in
>the Lab.
>
>The Bureaucrats stage a showing of the Stove with Chimney for their
>Minister, using standardized fuels in a lab setting, and have 3 PhD's and 2
>Lab Coated Technologists running the stove until the Minister goes back to
>his office. Then they get a Grant approved for their next Lab Project, and
>turn the stove over to "others" to install in the field. Their Project is
>considered a success because it worked very well in the Lab with 3 PhD's
and
>2 Lab Coated Technologists. Indeed, the stove worked so well in the Lab,
>that it can be sent immediately to the Field.
>
>There is obviously no need for a Field Test Program, user training, or
>follow-up on the stove. This money would be better spent doing more work in
>the Lab. Additionally, nobody in the Ministry want to work in the Field,
>because it is not a very nice place to work.
>
>When the "improved" stove fails, it is not the fault of the people in The
>Ministry, because the stove worked there. Clearly, the fault lies with the
>people who were responsible for distributing the stove system to the end
>users. But then, the Distributors report back to the Ministry that the End
>User is "resistant to change" and does not want to operate the stove the
way
>it was used in the Lab. "
>
>Now, isn't that a rather good formula to ensure that projects fail?
>Everybody looks good, except for the End User who is blamed for project
>failure.
>
>Abandonment of the "chimney stove" because it plugs up is proof of a poorly
>executed project. Some questions that should be addressed are:
>
> "Why was the stove system so poorly designed that unburned combustibles
are
>allowed to escape"
>
>"Why was the smoke and tar problem not discovered at the Lab Stage?"
>
>"Why were there not provisions made for occasional cleaning of the
chimney?"
>
>"Why were Gender Issues not considered?"
>
>"What would have happened to indoor air quality parameters if the "improved
>stove" was fed fuel of a quality that was fed to the charcoal stove?"
>
>Etc., etc, etc.
>
>If I tried to sell a stove in Canada that vented the products of combustion
>into the living space, I would be hit with enormous lawsuits, if I wasn't
>shot by the Families of the victims before the Case came to Trial. I can't
>see why it is any less unacceptable to subject poor people in third world
>Countries to the ravages of an inside vented stove.
>
>Kevin
>
>
>
>Subject: [STOVES] chimney
>
>
>Another reason for the failure of the improved cookstoves programme in
India
>was the insistance of the Ministry of Non-conventional Soruces that all
>cookstoves must have a chimney. The recommended chimney was an
>asbestos-cement pipe, having an internal diameter of 4 inches and length of
>10 feet. The cookstove worked satisfactorily for about 3 months, after
which
>the chimney choked. The lack of draft and blockage of an outlet for smoke
>caused more smoke inside the kitchen than the traditional cookstove. The
>housewife was shown, at the time of installation of the cookstove, how to
>clean the chimney, but somebody had to climb on the roof for this chore.
>Being a tropical country, India does not have the professional
chimneysweeps
>as in Northern Europe. The menfolk of the household considered this to be
>the responsibility of the housewife, and the housewife is generally
>physically fit to climb up on the roof of the house to clean the chimney.
As
>a result the chimney never got cleaned and the housewife just stopped using
>the improved stove.
>I relate this to warn others, who want to introduce a chimney in their
>programmes.
>Yours A.D.Karve
>We are now installing improved cookstoves based on charcoal or on biogas,
>and they do not need a chimney. As a result, there is great demand for our
>cooking devices as also for our fuels.
>
>

From yark at U.WASHINGTON.EDU Sun Jun 29 01:58:25 2003
From: yark at U.WASHINGTON.EDU (Tami Bond)
Date: Tue Aug 10 18:30:27 2004
Subject: chimney
In-Reply-To: <004f01c33d67$a9ec7e40$f99a0a40@kevin>
Message-ID: <SAT.28.JUN.2003.225825.0700.YARK@U.WASHINGTON.EDU>

Dear Stovers, and especially Dr. Karve,

Thanks for your input. I hope to follow this thread and distill some pros
and cons of chimneys. Please correct me if I miss the main points.

According to Dr. Karve, the main problem with the chimneys was blockage,
and that problem was perpetuated because the chimneys couldn't be
conveniently cleaned. This led to rejection of the stoves with chimneys.

Kevin Chisholm asked:
> "Why was the stove system so poorly designed that unburned combustibles are
> allowed to escape"
> "Why was the smoke and tar problem not discovered at the Lab Stage?"

Recall that this discussion was triggered by Dean Still's message that a
chimney was a simple solution to the indoor air problem. This implied that
the combustion was still poor, but one could solve some of the health
problems by adding a chimney and removing the exhaust from the living
space. Dr. Karve's experience indicates that WHEN combustion is poor, the
chimney is NOT a good solution because it will clog up. And this leads to
my first simplistic entry in the Chimney FAQ:

Q. Why should we worry about improving combustion for health reasons?
Can't we just put a chimney on the stove and get the exhaust out of the
house?
A. No, because the chimney is likely to clog when combustion is poor.

--> *** COMMENTS? COMPLAINTS? *** <---
- Can the chimney be a cure-all under other circumstances or with
different designs?
- Anyone have experience with chimney corrosion or other failures, or is
clogging the main problem?
- Any experience with long-lived, unclogged chimneys?

I would also like to answer Kevin's statement:

> If I tried to sell a stove in Canada that vented the products of combustion
> into the living space, I would be hit with enormous lawsuits...

At least here in the U.S., it is perfectly acceptable to vent the products
of stovetop natural gas combustion into the living space. This may not be
the most healthy of practices, but it does illustrate a possible tradeoff
between clean fuels and ventilation.

Best regards,

Tami

From andrew.heggie at DTN.NTL.COM Sun Jun 29 07:54:14 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: Charcoal from bamboo
In-Reply-To: <014d01c33a8b$a4dce130$1c9a0a40@kevin>
Message-ID: <SUN.29.JUN.2003.125414.0100.>

On Tue, 24 Jun 2003 15:52:18 -0300, Kevin Chisholm wrote:

>My concern here is that moisture from the interior of the charge would react
>with "already formed charcoal" on the outside of the charge, as per:
>H2O + C ----> CO + H2

Unlikely to be significant at normal retort or kiln temperatures, this
reaction needs higher than 700C before it's significant.
>
>> 2. Pre-drying is labour-intensive and takes much longer at temperatures
>below
>> that at which the bamboo is carbonised in the kiln, and
>
>Yes indeed. However, depending on climate conditions, it may be practical to
>cut the bamboo, stack it, and let it air dry for a period of time.

Yes, this is adding solar energy to the equation, you add 2.3MJ of
energy for every kg of water you remove.
>
>> 3. The charcoal yield from DRY bamboo and other biomass carbonised in an
>> airtight retort is around 50% so, if for example the un-carbonised
>> material's initial moisture content is 33.3%, the result of
>carbonising
>> each 300 kg of it will be to release 100 kg of 'steam' and 100 kg of
>> pyrolysis gases, leaving 100 kg of charcoal.
>
>OK!! This could form the basis for a criteria to determine if pre-drying of
>the bamboo is worthwhile or not.

IMO this is only important if you have a further use for the offgas,
if not and it is flared cleanly and used to heat the charge then it
will make no difference to the yield. In practice with a kiln some
char is used in driving off water, so the dryer the charge the better.

Wood shrinks about 10% from fiber saturation point to dry so output
from a kiln will be higher if dry wood is used. I wonder how the
ration of lignin:hemicelulose:celuslose differs between wood and
bamboo?

AJH

From andrew.heggie at DTN.NTL.COM Sun Jun 29 07:54:20 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: Charcoal from bamboo
In-Reply-To: <3EF8AC74.8DA5F5F5@legacyfound.org>
Message-ID: <SUN.29.JUN.2003.125420.0100.>

On Tue, 24 Jun 2003 22:55:01 +0300, Richard Stanley wrote:

>IE., How much do your gain in terms of total thermal energy of the charcoal
>minus the heat lost in making it in your retort and how does this compare to
>simply harvesting and burning the bamboo in the kitchen directly.

Best case with wood would be about 50% of the energy remaining in the
char, in practice it will be below 30%. In the controlled environment
of a retort it may be possible to get far better energy remaining in
the char, but a lot of this would be in the form of volatile tars
retained in the char. Mike Antal posted that his method could increase
the carbon yield by redepositing soot into the char (IIRC).

In the case of the sugar cane trash I imagine there is no possibility
of harvesting, storing and utilising it in a domestic stove, so
questions of overall efficiency do not enter the equation, by charring
it the waste material is turned into a useful resource that the
charcoal burner may profit from.

AJH

From andrew.heggie at DTN.NTL.COM Sun Jun 29 07:56:08 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: Gasification for biomass briquettes
In-Reply-To: <MABBJLGAAFJBOBCKKPMGGEPNCMAA.Gavin@aa3genergi.force9.co.uk>
Message-ID: <SUN.29.JUN.2003.125608.0100.>

On Fri, 20 Jun 2003 20:22:40 +0100, Gavin Gulliver-Goodall wrote:

>My experience of briquettes- compressed small particles - maybe bound in
>your circumstances, is that they break down into the small particles again
>as they are combusted (or gasified) will be as powder so in which case the
>char - if you get any will need briquetting again
>In fact the fact that they decompose in a nice controlled way ! is inherent
>in the advantages as the combustinon is more complete and air/fuel mixing
>more optimal.

Hi Gav, I'm still here :-)

My few experiments with carbonising pellets seemed to show the better
the pellet was densified the more it remained intact as a solid bit of
char. I put this down to the "better" pellets undergoing a more
thorough "plasticising" of lignin which reformed on cooling and was
able to form a char matrix after pyrolysis. Of course the black art of
pelletising is to form a pellet that is just strong enough to allow
handling and transport and dense enough to optimise transport,
anything "better" is a waste of power in compression. In fact I
believe some pellet firms are experimenting with binders to reduce
compression costs.

With the high electrical cost of densifying it does seem odd to
briquette prior to carbonising, but who can second guess the
economics?

AJH

From andrew.heggie at DTN.NTL.COM Sun Jun 29 07:54:23 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: 5 things from Kobus
In-Reply-To: <00e101c33afd$fec58400$2a47fea9@md>
Message-ID: <SUN.29.JUN.2003.125423.0100.>

On Wed, 25 Jun 2003 11:24:25 +0200, Crispin wrote:

>
>There is another option and I hope people are not wedded to the theory part
>of the ceramic chamber without at least considering other, as yet largely
>undiscussed, theories. I am refering to gas insulation using the incoming
>air as the insulator.

Which is rocket science, well jet engine science at least!
>
>Air is a very good insulator and can serve the same purpose as the cermaic
>parts much of the time. The combustion chamber can be metal provided that
>it is gas cooled (by the incoming air) so the life is increased.
>
>A perforated metal combustion chamber provides preheating of the air at very
>low cost and is, in practice, much easier to commercalize because it is
>light and strong and easy to fabricate in quantity.

Yet the cost is in supplying power to the air, to my mind it either
means a chimney or a fan or you end up with too much excess air,
reducing the temperature difference for good heat exchange. I guess
it's fine for a good fuel but in my fan powered burner I find I need
about 50% excess air to burn 50% mc wood.

Of course my aim was to make a cheap, lightweight, chimney less fire.
I took to a powered air supply because it gave turbulence, flattened
the flame path and hence decreased the height of the combustion
chamber, which increased the overall stability of the device. I would
be pleased to see if the same could be done with natural convection.

I also think it will be necessary to have a ceramic hearth as in
gasifying mode the char will be above 1000C and in contact with its
holder, which is a different case from burning the pyrolysis off gas
which is produced at <500C and it's combustion can take place in a
vortex where the flame is kept away from metal parts.
>
>As the challenge of making a very small fire boils down to keeping it hot
>and combusting well, it is difficult for me to see achieving this 'in the
>open'. The fire will have to be contained, and if the primary air is
>pre-heated, it can burn 'to the last drop' of fuel. Or the last nugget, if
>you will.
>
>Any stove that does not have pre-heated primary air will, near the end of
>the fuel, simply go out because the incoming air will chill the fuel below
>its ignition point. There will always be unburned charcoal lumps, typically
>more than 100 gms if fuelled with wood and fed cold air. On damp winter
>days it can be worse.

I think this is more to do with control of primary air, it's not at
all unusual for CO to increase as the batch turns to charcoal, the
problem with natural convection is that you cannot maintain enough
intimate contact (superficial velocity?) between primary air and
coals, hence the offgas becomes a mixture of CO2 and CO which is
difficult to burn, especially in the absence of the higher calorific
value pyrolysis gases. With a fan you have the option of increasing
air velocity and maintaining the char in an updraught CO gasifying
mode.

>The stove that can produce charcoal by gassifying the wood, followed by
>burning the charcoal,

Can we change that to pyrolysing the wood, cleanly burning the
pyrolysis offgas, followed by gasifying the resulting char and cleanly
burning the resultant CO?

>while doing so in an enclosed space with pre-heated
>primary air solves all the problems simultaneously: single device conversion
>to heat, low initial fuel load, complete burning of fuel, low emissions,
>controllability, low distribution cost, regional fabrication, mass marketing
>potential through commercial outlets.

I think we can already do this, the challenge is to do it with no
external power sources, economically.

AJH

From crispin at NEWDAWN.SZ Sun Jun 29 12:11:21 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:27 2004
Subject: Heat Insulation - John - further discussion.
Message-ID: <SUN.29.JUN.2003.181121.0200.CRISPIN@NEWDAWN.SZ>

Dear John

You wrote:
>1 The air layer reduces the radiation to the metal, but reduces
>the temperature of gasses reaching the pot,

What I haven't seen discussed is the amount of heat that is gained by the
air when cooling the metal skin and where it goes. I sense a certain
aversion to the whole topic but I can't see why.

If heat is removed from the hot metal wall, and it is taken into that 100%
excess air, then what's the difference? The air was there before and it was
cold when entering. The heat didn't go away and hide somewhere.

In general the subject it treated as if there were two completely separate
things going on:

the cooling of the metal resulting in a cooler and more heat-absorbent
chamber wall, with the predicted effect you clearly describe: a cooler
combustion chamber

and

the bringing of heat into the incoming air, an amount of heat exactly equal
to the cooling of the metal walls, which is added to the combustion
temperature.

The argument I received so far is that the cooling of the walls results in
lower combustion chamber temps, as you describe, but I seem to be alone in
saying, at least in this group, that the heat is added (recycled I called
it) to the very same combustion for no net difference.

If there is no difference in the actual effect on the combustion
temperature, of the average total amount of heat inside the chamber, then
there is a decided bonus for the metal stove maker because the parts will
last longer. That is something that cannot be claimed for raising the
temperature of the all-metal chamber by insulating the outside, and many
tests seem to support this idea. Insulated metal combustion chambers do not
last long.

Secondarily, and not related to wall temperature, is the fact that it is
possible to get a very small fire to burn properly when the incoming air is
preheated to something like the ignition temperature of the fuel. I believe
this idea cannot be challenged but I will still keep an open mind about it.
You once described to me the trouble the railway engineers go to to get
preheated secondary air on the locomotive.

Peter's washing machine stove is basically a large Tsotso Stove in layout
and it at least has some preheating of the secondary air. He mentions in
passing that the wood burned to white ash completely. That is actually
something that is not as common as we might think.

I agree, John, with your description of the swirling but I need to draw
something on paper to go into it further.

One problem I have seen, or faced on the drawing board, with large Tsotsos
is getting the air into the centre reaches of the secondary combustion area.
I feel that spinning it increases the largest diameter that it is possible
to feed fresh air well into the centre. For the largest boilers I have made
for Gone Rural in Malkerns Valley, I used a briefcase shaped grate only
150mm wide and feed hot air in from both long sides. It works pretty well
in the 30-40kw range and burns everything to dust.

By the way that grate is 3mm 3CR12 and they lasted about 4 years before
burning through. The entire side pretty much went at once. I don't have
wall temps for that though. The staff there just told me that it looks like
"the fires of hell" when it is going. It has a 2.2 metre high 6 inch steel
chimney. They have 3 and have ordered a 4th.

So, back the my main point: if the incoming air is cooling the metal walls,
where does the heat go and what is the net effect on combustion?

Regards
Crispin wishing I have a stove in my office

From adkarve at PN2.VSNL.NET.IN Sun Jun 29 13:23:55 2003
From: adkarve at PN2.VSNL.NET.IN (A.D. Karve)
Date: Tue Aug 10 18:30:27 2004
Subject: chimney
Message-ID: <SUN.29.JUN.2003.225355.0530.ADKARVE@PN2.VSNL.NET.IN>

A chimney serves the dual purpose of taking the flue gases out of the house
and also producing a strong draft. I have seen cookstoves having a chimney
that opened within the kitchen. When the householder was asked why he had a
chimney at all, his answer was that the stove would not burn properly if the
chimney was not there. This obviously means that the draft produced by the
chimney made the stove burn better. Good supply of primary air gives a
cleaner burn, but it also exhausts the fuel at a faster rate and leaves very
little charcoal behind. Charcoal is required by the rural households for a
very special reason. Many of the agricultural hand tools , like pickaxes,
machetes, axe heads and sickles are locally made by the village blacksmith.
The raw material from which these implements are made are old leaf springs
of trucks. They are heated and hammered into the desired shape. When
villagers need the services of the blacksmith, they also have to provide him
with the charcoal, which he uses for heating the leaf spring, because we do
not have mineral coal in our part of the country. Therefore, the charcoal
formed in the cookstove is carefully collected and saved. Were it just
thrown into the field, we too would have had our terra preta :-).
A.D.Karve
-----Original Message-----
From: Tami Bond <yark@U.WASHINGTON.EDU>
To: STOVES@LISTSERV.REPP.ORG <STOVES@LISTSERV.REPP.ORG>
Date: Sunday, June 29, 2003 11:30 AM
Subject: Re: [STOVES] chimney

>Dear Stovers, and especially Dr. Karve,
>
>Thanks for your input. I hope to follow this thread and distill some pros
>and cons of chimneys. Please correct me if I miss the main points.
>
>According to Dr. Karve, the main problem with the chimneys was blockage,
>and that problem was perpetuated because the chimneys couldn't be
>conveniently cleaned. This led to rejection of the stoves with chimneys.
>
>Kevin Chisholm asked:
>> "Why was the stove system so poorly designed that unburned combustibles
are
>> allowed to escape"
>> "Why was the smoke and tar problem not discovered at the Lab Stage?"
>
>Recall that this discussion was triggered by Dean Still's message that a
>chimney was a simple solution to the indoor air problem. This implied that
>the combustion was still poor, but one could solve some of the health
>problems by adding a chimney and removing the exhaust from the living
>space. Dr. Karve's experience indicates that WHEN combustion is poor, the
>chimney is NOT a good solution because it will clog up. And this leads to
>my first simplistic entry in the Chimney FAQ:
>
>Q. Why should we worry about improving combustion for health reasons?
>Can't we just put a chimney on the stove and get the exhaust out of the
>house?
>A. No, because the chimney is likely to clog when combustion is poor.
>
>--> *** COMMENTS? COMPLAINTS? *** <---
>- Can the chimney be a cure-all under other circumstances or with
>different designs?
>- Anyone have experience with chimney corrosion or other failures, or is
>clogging the main problem?
>- Any experience with long-lived, unclogged chimneys?
>
>I would also like to answer Kevin's statement:
>
>> If I tried to sell a stove in Canada that vented the products of
combustion
>> into the living space, I would be hit with enormous lawsuits...
>
>At least here in the U.S., it is perfectly acceptable to vent the products
>of stovetop natural gas combustion into the living space. This may not be
>the most healthy of practices, but it does illustrate a possible tradeoff
>between clean fuels and ventilation.
>
>Best regards,
>
>Tami
>

From andrew.heggie at DTN.NTL.COM Sun Jun 29 15:31:59 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: Heat Insulation - John - further discussion.
In-Reply-To: <007501c33d6c$0ede0720$a71f27c4@default>
Message-ID: <SUN.29.JUN.2003.203159.0100.>

On Sat, 28 Jun 2003 11:56:25 +0200, John Davies wrote:

>> If a vortex can be maintained in the centre of a rising column so most of
>> the heat production is going on, in effect in the middle of a tube made
>> entirely of air, then the 'outside' of the tube of air, which lies between
>> the burning vortex and the metal combustion chamber, insulates the metal
>> considerably.
>
>But what is really happening here? Heat is still traveling to the wall by
>radiation, which is cooled by the moving air layer. We have a problem here !

I cannot see it is a problem, the effect is real enough and as long as
it keeps the steel surface temperature low then the container life
will increase.

Whether the steel is heated by radiation or the turbulent mixing of
the combustion products and incoming air I don't know. I measure flame
temperatures of >1100C (my K type thermocouple is only calibrated to
1200C) so with radiative transfers being proportional to T^4 it could
be a great deal, except I believe the flame emissivity of the premixed
combustion to be low. I measure surface temperatures of 250C on the
outside surface.
AJH

From andrew.heggie at DTN.NTL.COM Sun Jun 29 15:32:02 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: Heat Insulation - John - further discussion.
In-Reply-To: <00aa01c33e59$16f78ec0$36d0fea9@desmond>
Message-ID: <SUN.29.JUN.2003.203202.0100.>

On Sun, 29 Jun 2003 18:11:21 +0200, Crispin wrote:

>Dear John
>
>You wrote:
>>1 The air layer reduces the radiation to the metal, but reduces
>>the temperature of gasses reaching the pot,

I missed this bit
>
>What I haven't seen discussed is the amount of heat that is gained by the
>air when cooling the metal skin and where it goes. I sense a certain
>aversion to the whole topic but I can't see why.
>
>If heat is removed from the hot metal wall, and it is taken into that 100%
>excess air, then what's the difference? The air was there before and it was
>cold when entering. The heat didn't go away and hide somewhere.

I agree with Crispin but 100% excess air points to the air cooling of
the metal work leading to far too much air being entrained. If the
amount of combustion air does not change then there is no reason why
combustion temperature should be less.
>
>In general the subject it treated as if there were two completely separate
>things going on:
>
>the cooling of the metal resulting in a cooler and more heat-absorbent
>chamber wall, with the predicted effect you clearly describe: a cooler
>combustion chamber
>
>and
>
>the bringing of heat into the incoming air, an amount of heat exactly equal
>to the cooling of the metal walls, which is added to the combustion
>temperature.
>
>The argument I received so far is that the cooling of the walls results in
>lower combustion chamber temps, as you describe, but I seem to be alone in
>saying, at least in this group, that the heat is added (recycled I called
>it) to the very same combustion for no net difference.

Agreed.

AJH

From andrew.heggie at DTN.NTL.COM Sun Jun 29 15:37:11 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: chimney
In-Reply-To: <000001c33e64$86ef7e80$dd5f41db@adkarvepn2.vsnl.net.in>
Message-ID: <SUN.29.JUN.2003.203711.0100.>

On Sun, 29 Jun 2003 22:53:55 +0530, A.D. Karve wrote:

>of trucks. They are heated and hammered into the desired shape. When
>villagers need the services of the blacksmith, they also have to provide him
>with the charcoal, which he uses for heating the leaf spring, because we do
>not have mineral coal in our part of the country. Therefore, the charcoal
>formed in the cookstove is carefully collected and saved. Were it just
>thrown into the field, we too would have had our terra preta :-).

Thank you, that has been the first justification I have seen for the
micro scale production of charcoal in cooking stoves.

AJH

From crispin at NEWDAWN.SZ Sun Jun 29 12:25:53 2003
From: crispin at NEWDAWN.SZ (Crispin)
Date: Tue Aug 10 18:30:27 2004
Subject: 5 things from Kobus
Message-ID: <SUN.29.JUN.2003.182553.0200.CRISPIN@NEWDAWN.SZ>

Dear Andrew

>>The stove that can produce charcoal by gassifying the wood, followed
>>by burning the charcoal,

>Can we change that to pyrolysing the wood, cleanly burning the
>pyrolysis offgas, followed by gasifying the resulting char and cleanly
>burning the resultant CO?

You can as far as I am concerned. Perhaps the best answer is to add new
fuel as the old fuel goes to char. Thee complex gas mix will always be
easily ignited. If the pieces are big, say 300 gm, that would only be
necessary after...30 minutes?

I have having second thoughts again about removing the secondary air
controller on the Vesto. Perhaps I should make more provision for secondary
and and go back to making it variable. It will work wonders in a lab and
will fail in the field due to problems with the "implementer" :)

Still, things are going OK - still trying to get costs down by endlessly
making tools to squish parts.

If you want to think of something horrific, Werner in Namibia has added a
burner to a Vesto that holds a mixture of 85% old engine oil and 15% diesel.
Smokes a bit...

And don't kick the can!

Regards
Crispin

From jmdavies at XSINET.CO.ZA Sun Jun 29 18:03:00 2003
From: jmdavies at XSINET.CO.ZA (John Davies)
Date: Tue Aug 10 18:30:27 2004
Subject: Fw: [STOVES] Stove chimneys
Message-ID: <MON.30.JUN.2003.000300.0200.JMDAVIES@XSINET.CO.ZA>

----- Original Message -----
From: "Peter Verhaart" <pverhaart@optusnet.com.au>
To: "John Davies" <jmdavies@XSINET.CO.ZA>
Sent: Sunday, June 29, 2003 8:45 AM
Subject: Re: [STOVES] Stove chimneys

> A chimney has to dispose of the gas produced by the fire. If the power is
> known as well as the air factor (real air flow rate)/(stoiciometric air
> flow), the mass rate of flow can be determined. The volumetric rate of
flow
> depends on the temperature of the gases.
> Af all these parameters reasonable guesses can be made.
> The chimney draft creates flow, in a narrow chimney much of the draft is
> converted to velocity but this is not important below 3 m/s.
> In a clean burning fire wood is converted to Carbon dioxide and water
> vapour. Oven dry wood consists roughly of 50% carbon, the remainder is
> Oxygen and Hydrogen roughly in the proportion of water.
> A stove burning 1 kg of (oven dry) wood in one hour, producing power at
the
> rate of 5 kW (equivalent to a large kitchen gas burner) forms 44/12 * .5
kg
> of CO2 or
> .5/12 * 22.4 m3 of CO2 gas at 273 K or 0.93 m3.
> If all the Oxygen in the air was used, it would result in a gas volume of
5
> * .93 m3 = 4.65 m3.
> At the same time water vapour is produced to the tune of .5 kg, or more
> depending on the moisture content. This gives .5/18 * 22.4 = 0.622 m3
water
> vapour
> If we assume an air factor of 2, we get 9.3 m3 Adding the water vapour
> gives 9.922 m3
>
> and, assuming an average fluegas temperature of 300 C, we get a volume
of
> (273 + 300)/ 273 * 9.922 m3 = 20.825 m3
> Per second this is 0.00578 m3/second.
> Divide this by the cross sectional area of the chimney in m2, and we get
> the velocity of the flue gases. If this exceeds 3 - 5 m/s, we should look
> for a larger diameter.
>
> Assuming the average temperature of the flue gas in the chimney to be 300
> C, its density is around half of the ambient air.
> The density difference times the local acceleration of gravity times the
> height of the chimney gives the draft in Pascals.
> All this, as Tom Reed will be only too eager to affirm, is all quite rough
> but it will probably work.
>
> Peter Verhaart
>
>
>
> At 12:15 28/06/03 +0200, you wrote:
> >Greetings,
> >
> >The sizing of a chimney is an exact science requiring complicated
> >computations and outside the scope of practice of most of us, who use the
> >empirical route to develop our stove systems.
> >
> >This brings one to the question. Has anybody come up with a simple
formula
> >to change the chimney effect with predictable results ?
> >
> >This can be divided into 2 areas. The effect of the chimney diameter, and
> >that of the height. I feel sure that there must be a correlation, within
> >certain limits, which will give the result of changes to the parameters
on
> >an existing system.
> >
> >Another item that comes to mind, is the effect of a horizontal section in
> >the chimney. Once again I come to the conclusion that an extra height of
X
> >times the horizontal length will be needed.
> >
> >Any ideas ?
> >
> >John Davies.
>
>
>

From dstill at EPUD.NET Sun Jun 29 10:14:24 2003
From: dstill at EPUD.NET (Dean Still)
Date: Tue Aug 10 18:30:27 2004
Subject: Chimney FAQ
Message-ID: <SUN.29.JUN.2003.071424.0700.DSTILL@EPUD.NET>

Tami writes:

"Recall that this discussion was triggered by Dean Still's message that a
chimney was a simple solution to the indoor air problem. This implied that
the combustion was still poor, but one could solve some of the health
problems by adding a chimney and removing the exhaust from the living
space."

Dear Tami,

Why do you say that a chimney could "solve some of the health
problems" associated with indoor air pollution. Do you think that a chimney
that lowers CO to 3.5ppm is leaving dangerous emissions in the room? Are
people who use wood burning heating stoves in the U.S. exposing themselves
to "some health hazards"? I know that smoke pollutes the outer air, of
course.

Defining combustion that is dangerous to health as poor combustion that
would clog a chimney is a type 2 logical error. The stove that we tested was
making almost no smoke and no creosote (clean combustion) but it was
raising levels of indoor CO to uncomfortably high levels. Dr. Karve defined
poor combustion as clogging chimneys. The stove as tested would not clog the
chimney for a long time. Even clean combustion creates dangerously high
levels of CO in enclosed rooms.

This said, all chimneys in the U.S. and elsewhere require regular cleaning.
Some air tight heating stoves that burn coolly clog up chimneys before
Spring but certainly all chimneys must be cleaned once or twice a year. How
often do we wash the dishes, vacuum the carpet, take out the trash?

The HELPS stove and the Justa stove both use a chimney to protect the health
of the family. Families unaware of it are taught the importance of cleaning
the chimney. Cleaning the chimney takes several hours usually once or twice
a year. Knives and machetes need sharpening every day if used for work.
Every machine no matter how simple or well engineered requires constant
maintenance. Changing oil in the car happens frequently for some lucky
folks.

Evidence shows that chimneys can be a very effective answer to indoor
pollution created by burning biomass, charcoal, coal, etc. The same
pollution in the home kills many children and adults around the world. A
chimney can prevent unnecessary death and requires a small amount of
maintenance, taking much less time than care of animals, crops, fruit trees,
hunting equipment, housing, irrigation equipment, tools, transportation,
children, washing of clothes, personal hygiene, etc.

Would anyone on this List want to have an unvented wood burning cooking
stove in the kitchen they now use?

All Best,

Dean

From Mbobker at AOL.COM Sun Jun 29 21:56:18 2003
From: Mbobker at AOL.COM (Mbobker@AOL.COM)
Date: Tue Aug 10 18:30:27 2004
Subject: Chimney FAQ
Message-ID: <SUN.29.JUN.2003.215618.EDT.>

Dear Stovers -

Besides removing unhealthful products of combustion from the living space, a
chimney also enhances draft and, if properly outfitted, draft control. Good
draft makes for better combustion, at least with the kind of non-stove
equipment with which I work. Better combustion means more complete use of fuel, fewer
incomplete poc, and less particulates -- economic and health benefits all.

Chimneys should be required by local code....I know that the concept of
building codes will make many of you chuckle but at least urban areas should try to
get to such public health regulations. NYC burned coal until the early
1950's when its use was prohibited by local law.

Michael Bobker
New York City

From elk at WANANCHI.COM Mon Jun 30 07:29:21 2003
From: elk at WANANCHI.COM (elk)
Date: Tue Aug 10 18:30:27 2004
Subject: K.C.Jiko
Message-ID: <MON.30.JUN.2003.142921.0300.ELK@WANANCHI.COM>

Kobus asks;

>How and where do you ignite the KCJ stove and have you made any
observations regarding the high and low power phases the fuel load undergoes
or any other observations that you could share with us?<

>And at what time defined point does the heat from the charcoal start to
fade off to levels below 700?C and gradually lower that would be considered
ineffective for pot simmering purposes.

Standard practice is to light the jiko from within the ashbox lower half.
typically either a small mound of kerosene -soaked ash is lit, or an empty
1/2 litre waxed milk carton is used as effective 'kindling'. Generally the
ignition to cooking temperature is facilitated by fanning a piece of
cardboard vigorously at the open ashbox door. Watch out for much pyrotechnic
sparking from the charcoal at this point (This does not occur with our
vendor's waste briquettes).

The ashbox door is pretty effective at controlling the power. Charcoal
stoves do have an advantage over wood-burning stoves here, as primary air
can be reduced 'way below the point where a flame is extinguished. At an
experienced guess, I'd say that full power is between 900 and 1100 C, and
power can be turned down to below 700 C simply by closing the door. A
typical burn to low simmer lasts just over two hours without additional
fuel.

rgds;
elk

 

--------------------------
Elsen L. Karstad
elk@wananchi.com
www.chardust.com
Nairobi Kenya

From rdboyt at YAHOO.COM Mon Jun 30 14:55:26 2003
From: rdboyt at YAHOO.COM (Richard Boyt)
Date: Tue Aug 10 18:30:27 2004
Subject: Practical Tips For Potters Making Improved Cooking Stoves,
Part 2-- Finding and Selecting the Clay
Message-ID: <MON.30.JUN.2003.115526.0700.RDBOYT@YAHOO.COM>

Stovers all:

The following material is the second part of a
condensation from the booklet "Practical Tips For
Potters Making Improved Cooking Stoves. Prepared by
Tim Jones, Illustrated by Debbie Riviere. Published
by Hofman Systems Engineering b.v., PO Box 642 3100
AP, Schiedam, The Netherlands (1993).

FINDING AND SELECTING CLAY

"It is good to be able to have more than one type of
clay available, as it greatly increases the chances of
being able to get the best and most suitable mixture.
A combination of a smooth, sticky clay with another
one containing more sand and coarse particles is often
ideal, once the best mixture of the two is worked out.
A supply of sand for adding to the various clays also
needs to be found.

"The first step is to ask people in the are if they
know of any places where clay is available. Older
people are the most useful, as they are most likely to
remember where clay was dug in the past.

"River banks often provide a variety of clays layered
on top of each other. Check the river to see if there
is a source of fine sand, as well, that could be
collected. Different parts of one sand bank will
provide a good variety of sand grains, the river
having done the sieving.

"Wherever there has been any diggin for bulding a
house, road construction, or an irrigation canal, the
clays can be seen and sampled. If a good clay is
found, then it can be followed by the digging of small
test holes in the ground in a place where it can be
dug and collected more easily. Good clays that lie
deeper below the surface... could still be within
digging range, once the top layers have been removed.
There may be larger deposites of good clay that have
not been found because of their depth, these are
available once located in this way.

My reaction to the above quotations from the booklet
"Tips For Potters" are:
1) I am surprised at the emphasis on sand as an
ingredient in a clay mix. I have avoided appreciable
quantities of sand in clay, because silica expands
rather suddenly, and sometimes catastrophically during
firing at about 575 degrees C (1100 deg F). This can
cause cracks to form, particularly in thick sections
which do not heat up evenly.

2) A drill bit welded to a rod to lengthen it can
drill several feet underground in search for clay
deposits. A pair of "jabbers" used by farmers to set
wooden fence posts can bring up sizeable quantities of
clay for testing.

The next (third) submission of condensations from the
booklet will be "Testing the Clay For Cooking Stoves".

Comments, questions, and suggestions would be
appreciated. These condensations are intended to
parallel and suppement my submissions on "Ceramics For
Stoves."

Hope this proves useful,

Dick Boyt

__________________________________
Do you Yahoo!?
SBC Yahoo! DSL - Now only $29.95 per month!
http://sbc.yahoo.com

From andrew.heggie at DTN.NTL.COM Mon Jun 30 17:03:15 2003
From: andrew.heggie at DTN.NTL.COM (Andrew Heggie)
Date: Tue Aug 10 18:30:27 2004
Subject: 5 things from Kobus
In-Reply-To: <00b901c33e7b$aff58ab0$36d0fea9@desmond>
Message-ID: <MON.30.JUN.2003.220315.0100.>

On Sun, 29 Jun 2003 18:25:53 +0200, Crispin wrote:

>You can as far as I am concerned. Perhaps the best answer is to add new
>fuel as the old fuel goes to char. Thee complex gas mix will always be
>easily ignited.

Yes this is the point I was trying to make, if you have both CO2 and
CO being given off at the bottom if the updraught device and you are
driving pyrolysis offgas off the top then the higher calorific value
in the offgas creates conditions that allow all the CO to burn out.

To maintain this condition you need continuous feed, a stoker.

> If the pieces are big, say 300 gm, that would only be
>necessary after...30 minutes?

Maybe, but this would be serial batch loaded. Very large batch loaded
devices, such as the cross draught gasifier David Beedie built for me,
suffer from a thermal runaway, especially if the wood is very dry. I
found once the device got up to temperature, even if primary air was
stopped off, pyrolysis was self sustaining and offgas was produced
with virtually no possibility of outside control, apart from spraying
in water.

The interesting thing to me was that with wet lumps of wood this
condition did not occur, my thoughts were that the endothermy lent to
the wood by it's water content allowed the char that developed on the
surface to burn at about the same rate as the offgas was produced and
the next layer dried. It still burned cleanly even with 50%mc wood and
the primary air could control it.

AJH

From rmiranda at INET.COM.BR Mon Jun 30 17:48:38 2003
From: rmiranda at INET.COM.BR (Rogerio Carneiro de Miranda)
Date: Tue Aug 10 18:30:27 2004
Subject: Practical Tips For Potters Making Improved Cooking Stoves,
Part 2-- Finding and Selecting the Clay
In-Reply-To: <20030630185526.76264.qmail@web13204.mail.yahoo.com>
Message-ID: <MON.30.JUN.2003.184838.0300.RMIRANDA@INET.COM.BR>

Richard: keep going, we are listening, great contribution. Rogerio Miranda

At 11:55 a.m. 30/06/03 -0700, Richard Boyt wrote:
>Stovers all:
>
>
>The following material is the second part of a
>condensation from the booklet "Practical Tips For
>Potters Making Improved Cooking Stoves. Prepared by
>Tim Jones, Illustrated by Debbie Riviere. Published
>by Hofman Systems Engineering b.v., PO Box 642 3100
>AP, Schiedam, The Netherlands (1993).
>
>FINDING AND SELECTING CLAY
>
>"It is good to be able to have more than one type of
>clay available, as it greatly increases the chances of
>being able to get the best and most suitable mixture.
>A combination of a smooth, sticky clay with another
>one containing more sand and coarse particles is often
>ideal, once the best mixture of the two is worked out.
> A supply of sand for adding to the various clays also
>needs to be found.
>
>"The first step is to ask people in the are if they
>know of any places where clay is available. Older
>people are the most useful, as they are most likely to
>remember where clay was dug in the past.
>
>"River banks often provide a variety of clays layered
>on top of each other. Check the river to see if there
>is a source of fine sand, as well, that could be
>collected. Different parts of one sand bank will
>provide a good variety of sand grains, the river
>having done the sieving.
>
>"Wherever there has been any diggin for bulding a
>house, road construction, or an irrigation canal, the
>clays can be seen and sampled. If a good clay is
>found, then it can be followed by the digging of small
>test holes in the ground in a place where it can be
>dug and collected more easily. Good clays that lie
>deeper below the surface... could still be within
>digging range, once the top layers have been removed.
>There may be larger deposites of good clay that have
>not been found because of their depth, these are
>available once located in this way.
>
>My reaction to the above quotations from the booklet
>"Tips For Potters" are:
>1) I am surprised at the emphasis on sand as an
>ingredient in a clay mix. I have avoided appreciable
>quantities of sand in clay, because silica expands
>rather suddenly, and sometimes catastrophically during
>firing at about 575 degrees C (1100 deg F). This can
>cause cracks to form, particularly in thick sections
>which do not heat up evenly.
>
>2) A drill bit welded to a rod to lengthen it can
>drill several feet underground in search for clay
>deposits. A pair of "jabbers" used by farmers to set
>wooden fence posts can bring up sizeable quantities of
>clay for testing.
>
>The next (third) submission of condensations from the
>booklet will be "Testing the Clay For Cooking Stoves".
>
>Comments, questions, and suggestions would be
>appreciated. These condensations are intended to
>parallel and suppement my submissions on "Ceramics For
>Stoves."
>
>Hope this proves useful,
>
>Dick Boyt
>
>
>__________________________________
>Do you Yahoo!?
>SBC Yahoo! DSL - Now only $29.95 per month!
>http://sbc.yahoo.com