April 2002 Gasification Archive

For more information to help people develop better stoves for cooking with biomass fuels in developing regions, please see our web site: http://www.bioenergylists.org

From psanders at ilstu.edu Tue Apr 2 11:34:43 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:44 2004
Subject: Gasification "against the draft" question
Message-ID: <4.3.1.2.20020402152812.01bb3800@mail.ilstu.edu>

To Tom Reed and other Stovers,

I am back from southern Africa. All went well and I am even more motivated
to do stoves work than before.

As I presented the gasifier to selected people, a question arose:

Is it ESSENTIAL that the gasification process proceed through the biomass
"against the draft"? That is, the IDD version of the Reed-Larson gasifier
is TOP lighted and burns downward while the only available primary air is
coming UPWARD through the biomass fuel. Is that absolutely essential?

Or could the fuel be bottom lighted, and then later be "starved" of primary
air (via good control of the entry of primary air under the fuel supply),
resulting with the advantages of gasification?

I am not really interested in a "definition" reply, but in a "practical"
response about what actually is happening in the pyrolysis and secondary
burning processes if bottom lighted to burn upward "with the draft", and if
that could be beneficial to the cook-stove objectives.

Thanks in advance for any replies.

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

-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/200202/
http://crest.org/discussiongroups/resources/stoves/ (Under construction)
http://www.ikweb.com/enuff/public_html/Stoves.html (Original)

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com

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-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From tombreed at attbi.com Tue Apr 2 13:13:33 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:44 2004
Subject: Gasification "against the draft" question
In-Reply-To: <4.3.1.2.20020402152812.01bb3800@mail.ilstu.edu>
Message-ID: <002001c1da9b$f4009730$4bc0fd0c@TOMBREED>

Dear Paul and All:

The "against the draft" (Inverted Downdraft, char making, top burning etc.)
gasifiers burn at a VERY constant rate until the volatiles are gone, making
4-25% characoal in the process (depending on moisture content). Recommended
for fuel of 0-25% moisture content, maybe not over 30%, and for making
charcoal.

The bottom lit gasifier is essentially an "updraft gasifier" which makes
very high levels of tarry gas and releases the volatiles with a minimum of
combustion of the charcoal on the bottom. My impression is that the rate of
gas production is not nearly as constant. However, this mode has the
advantage that it consumes all the charcoal as it is made. It is
recommended for VERY wet biomass.
~~~~~~~~~~~~~
Paul and Bob: we are driving to Illinois in mid-May and hope we can see you
and the Weldons then. Will you all be around. Hope to be demonstrating the
WoodGas CampStove.

Your pal, TOM REED BEF STOVEWORKS
I will run some tests in the future to determine the characteristics of the
close coupled updraft gasifier more accuately.

----- Original Message -----
From: "Paul S. Anderson" <psanders@ilstu.edu>
To: "Apolinário J Malawene" <ajmalawene01@hotmail.com>; "Bob and Karla
Weldon" <bobkarlaweldon@cs.com>; "Ed Francis" <cfranc@ilstu.edu>;
"Tsamba--Alberto Julio" <ajtsamba@zebra.uem.mz>; "Lily Coyle"
<astrozen2000@hotmail.com>; <stoves@crest.org>
Sent: Tuesday, April 02, 2002 2:42 PM
Subject: Gasification "against the draft" question

> To Tom Reed and other Stovers,
>
> I am back from southern Africa. All went well and I am even more
motivated
> to do stoves work than before.
>
> As I presented the gasifier to selected people, a question arose:
>
> Is it ESSENTIAL that the gasification process proceed through the biomass
> "against the draft"? That is, the IDD version of the Reed-Larson gasifier
> is TOP lighted and burns downward while the only available primary air is
> coming UPWARD through the biomass fuel. Is that absolutely essential?
>
> Or could the fuel be bottom lighted, and then later be "starved" of
primary
> air (via good control of the entry of primary air under the fuel supply),
> resulting with the advantages of gasification?
>
> I am not really interested in a "definition" reply, but in a "practical"
> response about what actually is happening in the pyrolysis and secondary
> burning processes if bottom lighted to burn upward "with the draft", and
if
> that could be beneficial to the cook-stove objectives.
>
> Thanks in advance for any replies.
>
> 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
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Alex English, english@adan.kingston.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
>
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com

List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From das at eagle-access.net Tue Apr 2 20:36:48 2002
From: das at eagle-access.net (Das)
Date: Tue Aug 31 21:37:44 2004
Subject: CO detection
Message-ID: <200204030647.g336lvr29756@saturn.eagle-access.net>

Alex

The dilution method which I outline provides for measurement of CO at the
inlet to a probe. Dilution is between the probe inlet and the detector
cell. Precision is determined by the precision of flow measurement for
dilution ratio and the detector precision. This is definitely NOT room
dilution. Please re read my description. I think you will agree. I can
also do a similar measurement with inexpensive sensors for CO2 , O2.

A. Das
Original Sources/Biomass Energy Foundation
Box 7137, Boulder, CO 80306
das@eagle-access.net

----------
> From: *.English <english@adan.kingston.net>
> To: Das <das@eagle-access.net>
> Cc: stoves@crest.org
> Subject: Re: CO detection
> Date: Tuesday, November 27, 2001 7:49 PM
>
> Hello Das,
>
> Good ideas!
> However I think we need to take it a little farther. Your method will
> sample gases in a chimney, just under a pot or in a vent hood
> exhaust, but it does not account for excess air dilution through the
> stove. Without measuring O2 , CO2 or total mass flow we can't fairly
> compare combustion quality.
>
> So I supose the stove testing operation could be in a box on a
> scale with a fixed air change rate supplied by a blower that supplies
> not less than perhaps twice the air requirements of the stove at
> maximum power. If the air flow paterns don't bias stove function,
> would this go far enough to allow for valid rough comparisons?
>
> Alex English
>
>
>
> > Dilution Method for CO Measurement Inside STOVES
> >
> > In response to the CO monitoring question I am familiar with the
Nighthawk
> > CO detector which provides digital readout 35 to 999 ppm with a 2.5
minute
> > refresh rate. It is available inexpensively ($40 - 60) at most
hardware
> > and building supply stores.
> > This can be rigged using an air tight enclosure around the detector, a
> > small vacuum pump ( 1 cfm compressor from a dead refrigerator free) and
a
> > pair of floating ball flow meters ($10 to $20 new) to adjust for a
1000:1
> > dilution ratio. This would give a round number readout of 10 X CO %
for
> > 3.5 to 99.9 % CO. This is good for fuel gas measurement. All this
for
> > under $100 in parts. This is a lot better than the gas analyzer
industry
> > standard offer of $2000 per gas.
> >
> > Environmental CO measurement around STOVES
> > I have always appreciated a CO detector in the working environment
around
> > gasifier and combustion equipment.
> > This inexpensive Nighthawk CO detector indication is blanked out to
> > display zero CO for all levels below 35 ppm per Underwriters Laboratory
> > requirements to reduce the number of fire department calls. (Full
story is
> > available at http://www.avweb.com/articles/codetect.html#comparison).
This
> > casts a pall of suspicion on those zero CO readings at the end of
indoor
> > turbo stove runs.
> >
> > Private airplane pilots have found an inexpensive faster reading lower
> > threshold digital readout CO detector for cockpit have prevailed on a
CO
> > detector manufacturer to produce a low level CO detector the AIM Model
935
> > Low-Level CO Monitor www.Aeromedix.com or via a 24-hour toll-free
> > telephone number: 888-362-7123.
> >
> >
> >
> > A. Das
> > Original Sources/Biomass Energy Foundation
> > Box 7137, Boulder, CO 80306
> > das@eagle-access.net
> >
> > ----------
> > > From: Tami Bond <Tami.Bond@noaa.gov>
> > > To: stoves@crest.org
> > > Subject: Re: CO detection
> > > Date: Friday, November 23, 2001 8:58 PM
> > >
> > >
> > > Stovers,
> > >
> > > > We've talked and talked about CO metering on this list, but none
> > > > of our technically-inclined members have come up with a workable
> > > > and affordable instrument design yet.
> > >
> > > What's 'affordable'? There are at least a couple of CO devices on the

> > > market in the 250-300 USD range. There are combustion analyzers for
> > > under 1000 USD that will measure CO, CO2. (Bacharach is the most
> > > famous, I think-- often used in gas-furnace service, for example--
> > > www.bacharach-inc.com).
> > >
> > > Is that too much? What kind of price ought we to target?
> > >
> > > Trouble with the cheap devices is the response time is slow (~10
> > > minutes) and if your burn is changing rapidly you might miss high and

> > > low spots. That may not matter if you are measuring IAQ. I'm of the
> > > opinion that real-time monitoring is needed, though.
> > >
> > > What do we need to measure? What species, response times, ranges? I
am
> > > trying to organize thoughts on this, and started writing something
for
> > > circulation that I should've finished a couple of weeks ago. Then I
got
> > > bogged down by explaining procedures from USEPA vs procedures that
are
> > > reproducible by our 'real' clients-- that is, people without money.
But
> > > the paper is still in the works, I promise!
> > >
> > > Tami
> > >
> > >
> > >
> > > -
> > > Stoves List Archives and Website:
> > > http://www.crest.org/discussion/stoves/current/
> > > http://www.ikweb.com/enuff/public_html/Stoves.html
> > >
> > > Stoves List Moderators:
> > > Ron Larson, ronallarson@qwest.net
> > > Alex English, english@adan.kingston.net
> > > Elsen L. Karstad, elk@wananchi.com www.chardust.com
> > >
> > > List-Post: <mailto:stoves@crest.org>
> > > List-Help: <mailto:stoves-help@crest.org>
> > > List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> > > List-Subscribe: <mailto:stoves-subscribe@crest.org>
> > >
> > > Sponsor the Stoves List: http://www.crest.org/discuss3.html
> > > -
> > > Other Biomass Stoves Events and Information:
> > > http://www.bioenergy2002.org
> > > http://solstice.crest.org/renewables/biomass-info/
> > > http://solstice.crest.org/renewables/biomass-info/carbon.shtml
> > >
> > > For information about CHAMBERS STOVES
> > > http://www.ikweb.com/enuff/public_html/Chamber.htm
> >
> > -
> > Stoves List Archives and Website:
> > http://www.crest.org/discussion/stoves/current/
> > http://www.ikweb.com/enuff/public_html/Stoves.html
> >
> > Stoves List Moderators:
> > Ron Larson, ronallarson@qwest.net
> > Alex English, english@adan.kingston.net
> > Elsen L. Karstad, elk@wananchi.com www.chardust.com
> >
> > List-Post: <mailto:stoves@crest.org>
> > List-Help: <mailto:stoves-help@crest.org>
> > List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> > List-Subscribe: <mailto:stoves-subscribe@crest.org>
> >
> > Sponsor the Stoves List: http://www.crest.org/discuss3.html
> > -
> > Other Biomass Stoves Events and Information:
> > http://www.bioenergy2002.org
> > http://solstice.crest.org/renewables/biomass-info/
> > http://solstice.crest.org/renewables/biomass-info/carbon.shtml
> >
> > For information about CHAMBERS STOVES
> > http://www.ikweb.com/enuff/public_html/Chamber.htm
> >
> >

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com

List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm

From tombreed at attbi.com Wed Apr 3 04:29:55 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:45 2004
Subject: CO detection
In-Reply-To: <200204030647.g336lvr29756@saturn.eagle-access.net>
Message-ID: <00be01c1db1b$f62dc840$4bc0fd0c@TOMBREED>

Dear Das and All:

Glad to have Das applying his longtermskills to helping us solve our
problems at GASIFICATION and STOVES. And for Das, I'm sure the Info Flows
Both Ways...

I have known Das for 25 years and always find his knowledge exceeds that of
most of us.... I am now in partnership with his son, Shivaym Ellis (my
God-Grandson) developing the WoodGas CookStove. Shivayam graduated from
Colorado School of Mines two years ago and is currently working on an NREL
charcoal-gas project in Georgia. What a father-son team.

Tom Reed GASIFICATION ADMININSTRATOR

----- Original Message -----
From: "Das" <das@eagle-access.net>
To: <english@adan.kingston.net>
Cc: <stoves@crest.org>
Sent: Tuesday, April 02, 2002 6:50 PM
Subject: Re: CO detection

> Alex
>
> The dilution method which I outline provides for measurement of CO at the
> inlet to a probe. Dilution is between the probe inlet and the detector
> cell. Precision is determined by the precision of flow measurement for
> dilution ratio and the detector precision. This is definitely NOT room
> dilution. Please re read my description. I think you will agree. I can
> also do a similar measurement with inexpensive sensors for CO2 , O2.
>
>
> A. Das
> Original Sources/Biomass Energy Foundation
> Box 7137, Boulder, CO 80306
> das@eagle-access.net
>
> ----------
> > From: *.English <english@adan.kingston.net>
> > To: Das <das@eagle-access.net>
> > Cc: stoves@crest.org
> > Subject: Re: CO detection
> > Date: Tuesday, November 27, 2001 7:49 PM
> >
> > Hello Das,
> >
> > Good ideas!
> > However I think we need to take it a little farther. Your method will
> > sample gases in a chimney, just under a pot or in a vent hood
> > exhaust, but it does not account for excess air dilution through the
> > stove. Without measuring O2 , CO2 or total mass flow we can't fairly
> > compare combustion quality.
> >
> > So I supose the stove testing operation could be in a box on a
> > scale with a fixed air change rate supplied by a blower that supplies
> > not less than perhaps twice the air requirements of the stove at
> > maximum power. If the air flow paterns don't bias stove function,
> > would this go far enough to allow for valid rough comparisons?
> >
> > Alex English
> >
> >
> >
> > > Dilution Method for CO Measurement Inside STOVES
> > >
> > > In response to the CO monitoring question I am familiar with the
> Nighthawk
> > > CO detector which provides digital readout 35 to 999 ppm with a 2.5
> minute
> > > refresh rate. It is available inexpensively ($40 - 60) at most
> hardware
> > > and building supply stores.
> > > This can be rigged using an air tight enclosure around the detector, a
> > > small vacuum pump ( 1 cfm compressor from a dead refrigerator free)
and
> a
> > > pair of floating ball flow meters ($10 to $20 new) to adjust for a
> 1000:1
> > > dilution ratio. This would give a round number readout of 10 X CO %
> for
> > > 3.5 to 99.9 % CO. This is good for fuel gas measurement. All this
> for
> > > under $100 in parts. This is a lot better than the gas analyzer
> industry
> > > standard offer of $2000 per gas.
> > >
> > > Environmental CO measurement around STOVES
> > > I have always appreciated a CO detector in the working environment
> around
> > > gasifier and combustion equipment.
> > > This inexpensive Nighthawk CO detector indication is blanked out to
> > > display zero CO for all levels below 35 ppm per Underwriters
Laboratory
> > > requirements to reduce the number of fire department calls. (Full
> story is
> > > available at http://www.avweb.com/articles/codetect.html#comparison).
> This
> > > casts a pall of suspicion on those zero CO readings at the end of
> indoor
> > > turbo stove runs.
> > >
> > > Private airplane pilots have found an inexpensive faster reading lower
> > > threshold digital readout CO detector for cockpit have prevailed on a
> CO
> > > detector manufacturer to produce a low level CO detector the AIM Model
> 935
> > > Low-Level CO Monitor www.Aeromedix.com or via a 24-hour toll-free
> > > telephone number: 888-362-7123.
> > >
> > >
> > >
> > > A. Das
> > > Original Sources/Biomass Energy Foundation
> > > Box 7137, Boulder, CO 80306
> > > das@eagle-access.net
> > >
> > > ----------
> > > > From: Tami Bond <Tami.Bond@noaa.gov>
> > > > To: stoves@crest.org
> > > > Subject: Re: CO detection
> > > > Date: Friday, November 23, 2001 8:58 PM
> > > >
> > > >
> > > > Stovers,
> > > >
> > > > > We've talked and talked about CO metering on this list, but none
> > > > > of our technically-inclined members have come up with a workable
> > > > > and affordable instrument design yet.
> > > >
> > > > What's 'affordable'? There are at least a couple of CO devices on
the
>
> > > > market in the 250-300 USD range. There are combustion analyzers for
> > > > under 1000 USD that will measure CO, CO2. (Bacharach is the most
> > > > famous, I think-- often used in gas-furnace service, for example--
> > > > www.bacharach-inc.com).
> > > >
> > > > Is that too much? What kind of price ought we to target?
> > > >
> > > > Trouble with the cheap devices is the response time is slow (~10
> > > > minutes) and if your burn is changing rapidly you might miss high
and
>
> > > > low spots. That may not matter if you are measuring IAQ. I'm of the
> > > > opinion that real-time monitoring is needed, though.
> > > >
> > > > What do we need to measure? What species, response times, ranges? I
> am
> > > > trying to organize thoughts on this, and started writing something
> for
> > > > circulation that I should've finished a couple of weeks ago. Then I
> got
> > > > bogged down by explaining procedures from USEPA vs procedures that
> are
> > > > reproducible by our 'real' clients-- that is, people without money.
> But
> > > > the paper is still in the works, I promise!
> > > >
> > > > Tami
> > > >
> > > >
> > > >
> > > > -
> > > > Stoves List Archives and Website:
> > > > http://www.crest.org/discussion/stoves/current/
> > > > http://www.ikweb.com/enuff/public_html/Stoves.html
> > > >
> > > > Stoves List Moderators:
> > > > Ron Larson, ronallarson@qwest.net
> > > > Alex English, english@adan.kingston.net
> > > > Elsen L. Karstad, elk@wananchi.com www.chardust.com
> > > >
> > > > List-Post: <mailto:stoves@crest.org>
> > > > List-Help: <mailto:stoves-help@crest.org>
> > > > List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> > > > List-Subscribe: <mailto:stoves-subscribe@crest.org>
> > > >
> > > > Sponsor the Stoves List: http://www.crest.org/discuss3.html
> > > > -
> > > > Other Biomass Stoves Events and Information:
> > > > http://www.bioenergy2002.org
> > > > http://solstice.crest.org/renewables/biomass-info/
> > > > http://solstice.crest.org/renewables/biomass-info/carbon.shtml
> > > >
> > > > For information about CHAMBERS STOVES
> > > > http://www.ikweb.com/enuff/public_html/Chamber.htm
> > >
> > > -
> > > Stoves List Archives and Website:
> > > http://www.crest.org/discussion/stoves/current/
> > > http://www.ikweb.com/enuff/public_html/Stoves.html
> > >
> > > Stoves List Moderators:
> > > Ron Larson, ronallarson@qwest.net
> > > Alex English, english@adan.kingston.net
> > > Elsen L. Karstad, elk@wananchi.com www.chardust.com
> > >
> > > List-Post: <mailto:stoves@crest.org>
> > > List-Help: <mailto:stoves-help@crest.org>
> > > List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> > > List-Subscribe: <mailto:stoves-subscribe@crest.org>
> > >
> > > Sponsor the Stoves List: http://www.crest.org/discuss3.html
> > > -
> > > Other Biomass Stoves Events and Information:
> > > http://www.bioenergy2002.org
> > > http://solstice.crest.org/renewables/biomass-info/
> > > http://solstice.crest.org/renewables/biomass-info/carbon.shtml
> > >
> > > For information about CHAMBERS STOVES
> > > http://www.ikweb.com/enuff/public_html/Chamber.htm
> > >
> > >
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Alex English, english@adan.kingston.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
>
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
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> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>

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From psanders at ilstu.edu Thu Apr 4 04:03:20 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:45 2004
Subject: Gasification "against the draft" question
In-Reply-To: <4.3.1.2.20020402152812.01bb3800@mail.ilstu.edu>
Message-ID: <4.3.1.2.20020404075313.0184cac0@mail.ilstu.edu>

Tom (and all) comments below:

At 04:13 PM 4/2/02 -0700, Tom Reed wrote:
>Dear Paul and All:
>
>The "against the draft" (Inverted Downdraft, char making, top burning etc.)
>gasifiers burn at a VERY constant rate until the volatiles are gone, making
>4-25% characoal in the process (depending on moisture content). Recommended
>for fuel of 0-25% moisture content, maybe not over 30%, and for making
>charcoal.
The above is a good summary statement, but below you say "with a minimum of
combustion of the charcoal on the bottom" and THEN say a contradictory
statement that "it consumes all the charcoal as it is made". Please explain.

Please also comment on the role of PRIMARY air control (as is the case in
the control of primary air in the Reed-Larson IDD unit and in the Juntos
stove gasifier) WITH THE SECONDARY COMBUSTION OF THE PRODUCED GASES
occurring at some identifiable distance from the pyrolysis zone. Is that
in fact the case in what you describe in the paragraph below? If not
(therefore meaning that plenty of air can enter in the case below), is that
essentially what is occurring in the Rocket stove and other
"enclosed-chimney-vertical-heat-column" combustion units that do not
exercise control over the amount of primary air entering at the bottom?

>The bottom lit gasifier is essentially an "updraft gasifier" which makes
>very high levels of tarry gas and releases the volatiles with a minimum of
>combustion of the charcoal on the bottom. My impression is that the rate of
>gas production is not nearly as constant. However, this mode has the
>advantage that it consumes all the charcoal as it is made. It is
>recommended for VERY wet biomass.
> ~~~~~~~~~~~~~
>Paul and Bob: we are driving to Illinois in mid-May and hope we can see you
>and the Weldons then. Will you all be around. Hope to be demonstrating the
>WoodGas CampStove.

I will be away on 7 to 9 May and I MIGHT be away on the week of 11 May to
19 May. We are anxious to see the WG CampStove.

Paul

>Your pal, TOM REED BEF STOVEWORKS
>I will run some tests in the future to determine the characteristics of the
>close coupled updraft gasifier more accuately.
Original question was:
> > Is it ESSENTIAL that the gasification process proceed through the biomass
> > "against the draft"? That is, the IDD version of the Reed-Larson gasifier
> > is TOP lighted and burns downward while the only available primary air is
> > coming UPWARD through the biomass fuel. Is that absolutely essential?
> >
> > Or could the fuel be bottom lighted, and then later be "starved" of
>primary
> > air (via good control of the entry of primary air under the fuel supply),
> > resulting with the advantages of gasification?
> >
> > I am not really interested in a "definition" reply, but in a "practical"
> > response about what actually is happening in the pyrolysis and secondary
> > burning processes if bottom lighted to burn upward "with the draft", and
>if
> > that could be beneficial to the cook-stove objectives.
> >
> > Thanks in advance for any replies.
> >
> > Paul
> >

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From psanders at ilstu.edu Mon Apr 8 09:42:24 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:45 2004
Subject: Stoves - Matrix of issues
Message-ID: <4.3.1.2.20020408125301.018729d0@mail.ilstu.edu>

Stovers,

After my highly successful trip to southern Africa in March, I am finally
getting back to the old groove. One topic is the identification of the
key "components" to our "stoves" problem. We listed in previous months 3
(three) components: 1) fuel, 2) combustion chamber, and 3) uses (or what
I previously called cooking but now feel should be broader to include
heating and even small scale industrial uses like a bread bakery).

Now I think we should add to that list a fourth component: 4) "physical
structure" of the stove. Structure is NOT the combustion chamber, but all
the rest such as the side walls, the height issues, the materials of
construction, the safety of the structure, and more.

Therefore, I consider that the 4 components could form a matrix in which we
can identify BOTH the specifics of each component and ALSO the interactions
BETWEEN the components. I will make the matrix very small so it should
come through okay via e-mail. You can imagine (or draw in) the vertical lines
F = Fuel(s) C = Combustion chamber(s)
S = Structure U = Uses, as in domestic processes (cooking, heating,
etc) or even small industrial uses.

F C S U
----------------------------------------------------------------
F FX

---------------------------------------------------------------
C CX

---------------------------------------------------------------
S SX

--------------------------------------------------------------
U UX

--------------------------------------------------------------

1. The diagonal line of FX down to DX are the cell for simple description
of the F, C, S, and D. For example, how many fuels can you name? And
then, of that great number of fuels, which ones are found in your
geographic area of work, and which ones will actually be the foci of your
efforts.

2. Above the diagonal there are 6 cells, and below the diagonal are
another 6 cells. Those cells can be called F-C and F-S and F-U and
C-F,,,,,,,, etc. And in those cells are where we focus attention of the
interaction between the 2 named components. For example, the fuel and
combustion chamber relationship is acknowledged as being very important,
but there are variations or combinations that work better than
others. Here we have much work to do, OR we need to clearly state how our
already completed work fits into a particular cell of the matrix.

3. Additional factors that have impact are the challenges of cost (value
for the investment by whom), the social challenges (cultural acceptance of
burning dung, etc) or physical science issues (moisture content of fuels,
control of secondary air, etc) or environmental challenges (stop severe
ecosystem damage, etc).

I hope that this helps us focus our discussions and work.

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

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From psanders at ilstu.edu Mon Apr 8 17:26:21 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:45 2004
Subject: Who will submit a Shell Grant application for stoves?
Message-ID: <4.3.1.2.20020408212158.01873c80@mail.ilstu.edu>

Dear Stovers (and please forward to the ETHOS group),

Not much talk by Stovers about the Shell Foundation grants. There is an
element of competition even among ourselves, so maybe people are not
wanting to reveal their intentions. But it would be interesting to know
how many Stovers intend to submit proposals. No details, just a counting,
and maybe a topic or title if willing to submit.

Example: Paul Anderson and Crispin Pemberton-Pigott intend to submit a
proposal dealing with the Juntos stoves (several variations) and the area
of application is in southern Africa near Swaziland-Mozambique-South Africa.

Anyone else???

The deadline for the Preliminary proposals is 25 April, so there is still
time to participate.

Paul

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From psanders at ilstu.edu Mon Apr 8 17:58:25 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:45 2004
Subject: Assist with Shell Grant please
Message-ID: <4.3.1.2.20020408213354.01867220@mail.ilstu.edu>

Stovers and friends,

I am seeking possible collaborators with the Shell Grant that is being
prepared about the Juntos stoves (gasifier issues, etc.). I have several
collaborators in southern Africa to various degrees, but others could still
be welcome.

Specifically I am looking for the following ADDITIONAL collaborators (who
will get part of the money, but who provide some essential extras.):

1. Emissions testing. Must be scientific and rigorous, with appropriate
quantification according to the variables of fuels and combustion
chambers. You need to have the equipment and knowhow. We provide the
stove(s) and info about the fuels. Could be compatible with graduate or
honors student research, or be a "paid for" service. More than one
testing entity could be involved. Several thousand dollars could be
available, but this is not the big money expenditures of the grant. Highly
important to do this, but it is not the focus of the entire grant.

2. Efficiency testing: Very similar to the above statement, but this is
more closely linked to the issues of combustion chambers and the stove
structures (placement of the pots to get higher efficiency). Will deal
with at least three "energy settings" that are high, medium and low (as in
fast-to-boil, medium and simmer).

3. External examiners: We will seek an independent review periodically
during the 3 years of the Shell grant. Benefits probably include travel
to and within southern Africa for "on-site" observation of stove issues
with the communities of implementation. Prior knowledge of African
realities desired (or required).

Any candidates? Feel free to "self-nominate" or the suggest
others. Preliminary indications are needed by 20 April. (sooner is
better.) Be sure to indicate the "value" that is being contributed to the
project, as well as the amount of funding needed to deliver that value (can
be a range of values.) For example, professors who provide laboratory
services at the cost of paying the student technicians plus materials can
declare a value that includes the professor's (or other staff's) time.

Please feel free to make suggestions about any of the above. Write to the
whole stoves list if you wish, or send directly to me
at psanders@ilstu.edu for individualized consideration.

Please remember that this is the Juntos Stoves Project, and that Juntos
means "Together". Your participation is encouraged. And please feel free
to forward this message to others who might be interested (such as those in
the ETHOS group). I hope to hear from you soon.

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From ronallarson at qwest.net Mon Apr 8 19:59:03 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:45 2004
Subject: Stoves - Matrix of issues
In-Reply-To: <4.3.1.2.20020408125301.018729d0@mail.ilstu.edu>
Message-ID: <010601c1df83$9f068900$c8f76641@computer>

Paul (cc stoves):

I like your proposal - and thank you for starting this new line of
inquiry.

I have one suggestion to make - which is that air supply/control is of
very great importance - but is not (I think) specifically noted in your
first outline . I am pretty sure you want this to be included in your
second item c) combustion chamber. But as this is not explicitly spelled
out, I ask for your thoughts. My recommendation is that air control ONLY be
discussed in that c) category (and it not appear as a "structure" or other
topic).

Let me also suggest that the subject of "uses" is especially important
when discussing charcoal-making stoves - which is about the only place in
our discussion where air control has been mentioned. My perception is that
the emphasis on clean stoves in the US is now being handled almost entirely
by careful and clever primary and secondary air control (not catalytic
devices). I am afraid we have just barely begun to understand this topic
for simple cheap rural stoves - as proven by the poorer pollution
performance of some stoves that are ostensibly more efficient. My
discussions with John Crouch some time ago told me that we are going to have
to be a lot more clever about handling secondary air before we have an
acceptable stove.

This raises the issue of where we should expect to find data of the type
produced by Drs. Kirk Smith and Tami Bond - grams of various emissions per
unit something (kg fuel, kW, kWh output, hour, etc). Same for the resulting
health impacts. I guess these should appear under the topic "combustion"
also?

As someone interested in charcoal-making - I hope we can agree that your
"C" can be interpreted to mean "conversion" (with two outputs).

See a few more notes below.

----- Original Message -----
From: Paul S. Anderson <psanders@ilstu.edu>
To: Apolinário J Malawene <ajmalawene01@hotmail.com>; Bob and Karla Weldon
<bobkarlaweldon@cs.com>; Ed Francis <cfranc@ilstu.edu>; Tsamba--Alberto
Julio <ajtsamba@zebra.uem.mz>; Lily Coyle <astrozen2000@hotmail.com>;
<stoves@crest.org>
Sent: Monday, April 08, 2002 12:50 PM
Subject: Stoves - Matrix of issues

> Stovers,
>
> After my highly successful trip to southern Africa in March, I am finally
> getting back to the old groove. One topic is the identification of the
> key "components" to our "stoves" problem. We listed in previous months 3
> (three) components: 1) fuel, 2) combustion chamber, and 3) uses (or
what
> I previously called cooking but now feel should be broader to include
> heating and even small scale industrial uses like a bread bakery).
>
> Now I think we should add to that list a fourth component: 4) "physical
> structure" of the stove. Structure is NOT the combustion chamber, but all
> the rest such as the side walls, the height issues, the materials of
> construction, the safety of the structure, and more.
>
(RWL): Kirk has done a good job of balancing the various ways that
carbon can be converted and where the energy goes. I guess that all of the
carbon computations should be under "C", but that the energy flows should be
mostly split between "C" and "S". OK?

> Therefore, I consider that the 4 components could form a matrix in which
we
> can identify BOTH the specifics of each component and ALSO the
interactions
> BETWEEN the components. I will make the matrix very small so it should
> come through okay via e-mail. You can imagine (or draw in) the vertical
lines
> F = Fuel(s) C = Combustion chamber(s)
> S = Structure U = Uses, as in domestic processes (cooking, heating,
> etc) or even small industrial uses.

(RWL): I agree that it is important to limit the matrix to four items.
A fifth element (such as for "air") will introduce more complexity than we
need. I am tempted to suggest "uses" is of a different character than the
others - but let's see what happens. I think that we will find a lot of
differences in the type of cooking (baking vs broiling vs boiling, etc).
>
>
> F C S U
> ----------------------------------------------------------------
> F FX
>
> ---------------------------------------------------------------
> C CX
>
> ---------------------------------------------------------------
> S SX
>
> --------------------------------------------------------------
> U UX
>
> --------------------------------------------------------------
>
> 1. The diagonal line of FX down to DX are the cell for simple
description
> of the F, C, S, and D. For example, how many fuels can you name? And
> then, of that great number of fuels, which ones are found in your
> geographic area of work, and which ones will actually be the foci of your
> efforts.
>
> 2. Above the diagonal there are 6 cells, and below the diagonal are
> another 6 cells. Those cells can be called F-C and F-S and F-U and
> C-F,,,,,,,, etc. And in those cells are where we focus attention of the
> interaction between the 2 named components. For example, the fuel and
> combustion chamber relationship is acknowledged as being very important,
> but there are variations or combinations that work better than
> others. Here we have much work to do, OR we need to clearly state how our
> already completed work fits into a particular cell of the matrix.
>
(RWL): It will be interesting to see how the upper and lower off-diagonal
elements get treated - and whether we need 12 such cells or can get by with
only 6. As an example of the F-U and U-F cells, and my desire to say I
could not find a way to convert dung to charcoal in a charcoal-making
stove - is that the fuel dictating a use (F-U?) - or is this a U-F where the
use is eliminating a fuel? Or does it matter? I think it the last - and
that 6 might generally be the case (and if we had 12 boxes to fill, I might
say the same thing twice - which we surely don't want).

> 3. Additional factors that have impact are the challenges of cost (value
> for the investment by whom), the social challenges (cultural acceptance of
> burning dung, etc) or physical science issues (moisture content of fuels,
> control of secondary air, etc) or environmental challenges (stop severe
> ecosystem damage, etc).

(RWL): I am now a bit confused. Are you suggesting more elements - or
that we need to allocate these into the 10 (or 16) boxes? We could have a
separate matrix for each topic - or list them in order of importance - or
list them always in the same place (physical parameter first, then costs,
then social challenges, then ..., then ....?? As an example, we "know"
that charcoal-making stoves work less well as "moisture content of fuels"
increases. Where do we discuss this relationship (F-U?). Do we expect
there is always something interesting to say in every category?

Concerning other items in your list:
a. I suggest that costs may need to be broken into all four main
categories (F,C,U, S) - but probably not in all six off-diagonal entries,
with separate first cost and continuing elements.
b. Social challenges? - Good addition - needed to separate into 10
categories? (Probably so.)
c. Physical (come first? Maybe call "technical"? (see below))
d. Environmental ? (good addition - need to think more - but probably
like the others

So now we are up to about (4+6)*4=40 different topics. (trying to keep the
number down)

As I tried to follow your logic, I remembered a time when I worked for
the US Congress' Office of Technology Assessment (OTA). The TA literature
at that time had a seven-letter acronym called EPISTLE (Economic, political,
institutional, social, technological, legal, environmental). Any of these,
of course, could kill a technology and I'm sure we could find an example of
each for a real proposed technology being "killed" (and that could possibly
have been predicted in advance). With your system, I suggest we might
collapse to the four-letter "TEES" where "S" is really "SLIP".

Just a thought. Thanks again for starting this new thread. Have I got
your ideas correct?

Ron

(Sorry for the long delay from my last attention to "stoves" list
topics - but your interesting proposal came as I just finished a big project
on Sunday - and I should be caught up fairly soon. I have some thoughts on
your last questions to Tom Reed (I think unanswered) - but will wait a few
days.)

>
> I hope that this helps us focus our discussions and work.
>
> 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
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
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> -
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> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
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>

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From psanders at ilstu.edu Tue Apr 9 05:41:45 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:45 2004
Subject: Stoves - Matrix of issues
In-Reply-To: <4.3.1.2.20020408125301.018729d0@mail.ilstu.edu>
Message-ID: <4.3.1.2.20020409091536.01860530@mail.ilstu.edu>

Ron, Thanks for the thoughtful reply about the matrix.

I agree totally with your observations (except I did not understand the
"TEES" comment at the end, which seemed to be a minor point of your comments.)

Yes, air control is part of the combustion chamber issue. PERHAPS
(optional) some parts of the S (structure) could be part of the C
(combustion chamber). That is a matter of design that serves 2 functions.

Yes, charcoal making (or anything else that takes place with the "burning"
of the fuel) is MAINLY an issue for the C (combustion chamber), but of
course it is influenced by the F (fuel). To an even LESSER DEGREE,
charcoal making could be viewed as a U (use, that assumes intentional
action to make and save charcoal and not merely have a byproduct to be
thrown away) and could be influenced by the S (structure that lets the
charcoal be removed rather than just being burned because the structure had
no access to remove the charcoal). This is a good example of how all 4
aspects are interrelated, but ONE is vastly more important that the others.

Yes, I did not want the cost, environment, etc issues to be in the matrix,
but rather to be discussion points for the cells of the matrix. IF those
issues are viewed as a third dimension of the matrix (such as layers behind
the front main matrix), that could be helpful as long as we do not feel
that we must discuss every cell in every layer every time.

Among your EPISTLE "issues", the political and legal ones are SOOO
important to implementation, but also SOOO unimportant to the design
work. AFTER the better stove(s) are available and tested, THEN political
and legal become more important. (But let us not forget to lay the
groundwork so that the political and legal people do not turn against the
progress in stove designs before we even get a chance to show the impact of
any improvements.)

About the "top half" or bottom half or all of the matrix, I have no
defining comments except to say that the diagonal line of FX to UX must
be included in the discussion. So it is not an issue of 6 or 12
cells. It is an issue of 10 or 16 cells in the matrix.

I hope that helps.

I have deleted the prior message so as to keep this response short in bytes.

Paul

At 10:58 PM 4/8/02 -0600, Ron Larson wrote:
>Paul (cc stoves):
> I like your proposal - and thank you for starting this new line of
>inquiry.

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From dstill at epud.net Tue Apr 9 09:54:27 2002
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:37:45 2004
Subject: Rocket Stove Principles
Message-ID: <001401c1dfa8$b2d83c60$751d66ce@default>

Dear Friends,

I was typing up Larry's latest simple stove principles for Aprovecho's
newsletter, "News From Aprovecho", (two to three times a year, $30/year,
describes activity, I'm editing number 59) and thought I'd send it along.

Reflecting on the Rocket I might point out a interesting point: no secondary
air. I've tried adding heated secondary air into the top end of the internal
chimney above the combustion chamber but haven't noticed an improvement in
amount of smoke or in fuel efficiency. I ended up thinking that enough
primary air is left at the top of the combustion zone anyway. Adding air may
just reduce temperatures. I'll test this further with better equipment.

The Rocket stove is trying to create supportive conditions for complete
initial combustion which seems to pretty much work when the right amount of
fuel is introduced. The added draft created by the insulated chimney above
the fire pulls in lots of air, which like a fan, makes a hotter, vigorous
burn.

Anyway, here are Larry's principles of stove design:

Best,

Dean

Rocket Stove Principles

Dr. Larry Winiarski
Technical Director
Aprovecho Research Center
Apro@efn.org

1.) Insulate, particularly the combustion chamber, with low mass, heat
resistant materials in order to keep the fire as hot as possible and not to
heat the higher mass of the stove body.

2.) Within the stove body, above the combustion chamber, use an insulated,
upright chimney of a height that is about two or three times the diameter
before extracting heat to any surface (griddle, pots, etc.).

3.) Heat only the fuel that is burning (and not too much). Burn the tips of
sticks as they enter the combustion chamber, for example. The object is NOT
to produce more gasses or charcoal than can be cleanly burned at the power
level desired.

4.) Maintain a good air velocity through the fuel. The primary Rocket stove
principle and feature is using a hot, insulated, vertical chimney within the
stove body that increases draft.

5.) Do not allow too much or too little air to enter the combustion chamber.
We strive to have stoichiometric (chemically ideal) combustion: in practice
there should be the minimum excess of air supporting clean burning.

6.) The cross sectional area (perpendicular to the flow) of the combustion
chamber should be sized within the range of power level of the stove.
Experience has shown that roughly twenty-five square inches will suffice for
home use (four inches in diameter or five inches square). Commercial size is
larger and depends on usage.

7.) Elevate the fuel and distribute airflow around the fuel surfaces. When
burning sticks of wood, it is best to have several sticks close together,
not touching, leaving air spaces between them. Particle fuels should be
arranged on a grate.

8.) Arrange the fuel so that air largely flows through the glowing coals.
Too much air passing above the coals cools the flames and condenses oil
vapors.

9.) Throughout the stove, any place where hot gases flow, insulate from the
higher mass of the stove body, only exposing pots, etc. to direct heat.

10.) Transfer the heat efficiently by making the gaps as narrow as possible
between the insulation covering the stove body and surfaces to be heated but
do this without choking the fire. Estimate the size of the gap by keeping
the cross sectional area of the flow of hot flue gases constant. EXCEPTION:
When using a external chimney or fan the gaps can be substantially reduced
as long as adequate space has been left at the top of the internal short
chimney for the gasses to turn smoothly and distribute evenly. This is
tapering of the manifold. In a common domestic griddle stove with external
chimney, the gap under the griddle can be reduced to about one half inch for
optimum heat transfer.

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From ronallarson at qwest.net Tue Apr 9 18:46:20 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:45 2004
Subject: Stoves - Matrix of issues
In-Reply-To: <4.3.1.2.20020408125301.018729d0@mail.ilstu.edu>
Message-ID: <006601c1e042$a4fa1240$ece06641@computer>

Hi Paul (cc stoves):

(see below)

----- Original Message -----
From: Paul S. Anderson <psanders@ilstu.edu>
To: Ron Larson <ronallarson@qwest.net>; Apolinário J Malawene
<ajmalawene01@hotmail.com>; Bob and Karla Weldon <bobkarlaweldon@cs.com>; Ed
Francis <cfranc@ilstu.edu>; Tsamba--Alberto Julio <ajtsamba@zebra.uem.mz>;
Lily Coyle <astrozen2000@hotmail.com>; <stoves@crest.org>
Sent: Tuesday, April 09, 2002 8:49 AM
Subject: Re: Stoves - Matrix of issues

> Ron, Thanks for the thoughtful reply about the matrix.
>
> I agree totally with your observations (except I did not understand the
> "TEES" comment at the end, which seemed to be a minor point of your
comments.)
>
(RWL): Sorry. I took the 7-letter word "EPISTLE" (defined last time)
and broke it into the two 4-letter words: "TEES" and "SLIP" (with "S"
overlapping). "TEES" is therefore Technical + Economic+Environmental+Social
(with "S" or "Social" now including LIP = Legal +Institutional+Political).
(TEES is not "minor" - it is just a way to remember the order - which I
think is exactly your own.

<snip>
>
> Among your EPISTLE "issues", the political and legal ones are SOOO
> important to implementation, but also SOOO unimportant to the design
> work. AFTER the better stove(s) are available and tested, THEN political
> and legal become more important. (But let us not forget to lay the
> groundwork so that the political and legal people do not turn against the
> progress in stove designs before we even get a chance to show the impact
of
> any improvements.)
>
(RWL): I think you are perhaps saying we don't need to include "LIP"
(Maybe "SLIP") within all the 10 matrix elements defined by your . And this
probably is also true of many of the ten of your FCSU elements. So maybe
the 40 separate "descriptors" I noted could realistically drop to only
twenty or thirty "descriptors". We will end up with a better number after
we try writing a few of these. There is still a question in my mind whether
"LIP" or "SLIP" should be just done once outside of the matrix.

<snip>
>
> I have deleted the prior message so as to keep this response short in
bytes.
>
> Paul
>

(rwl): Me too.

Ron

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From psanders at ilstu.edu Thu Apr 11 08:43:37 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:45 2004
Subject: Gasifier fundamental question
In-Reply-To: <008f01c1e167$889c24a0$2a47fea9@md>
Message-ID: <4.3.1.2.20020411101646.00c77620@mail.ilstu.edu>

Stovers (especially Tom and Ron)

Crispin at New Dawn Engineering wrote to me:
>Dear Paul
... (snip)
>I wanted to see what people came
>up with as a reason for burning from the top down. I am singularly
>unimpressed with the reasoning. I suspect that it is a 'given' not to be
>questioned. I am still waiting to hear ANY reasonable explanation for not
>smoking off the wood in any pattern or position. Charcoal is made by
>running the smoke (from the charing process) through the uncharred wood.
>Why should it be different with a stove??
.....

VERY sound statements. Now, what do the experts say?

I can imagine that the issues of "fire present" versus "heat without fire,
as in a retort" could be very important, especially for issues of control
of the amount of gases being generated.

I think we have a requirement of burning the gases soon after generation
because we are dealing with SMALL stoves and POOR economic
conditions. And that also might influence what is and is not possible
with top lighting versus bottom lighting.

IMPORTANT NOTE: It is not really "top" vs "bottom" because SOME
gasifiers force the air downward through the fuel, making it the equivalent
of bottom lighting where the air flow is upward. Instead, the issue
focuses on the air flow going AGAINST the direction of the pyrolysis
front. Tom Reed called his stove the IDD (Inverted DownDraft gasifier)
and many people do not like that expression, because it is really an
UpDraft, BUT it is directed AGAINST the progression of the burning that
comes downward from the top

Therefore, when the draft and the progression of the burning are in the
SAME direction, IS there control of the gasification process (as separate
from the "burning" of the char after (or simultaneously with) the gases
having been driven off?

What this boils down to is this: How are the "against burn" draft and the
"with burn" draft crucial with the gasification process as envisioned for
the small-scale domestic household stoves such as the Juntos stoves or the
Reed-Larson IDD stoves or even the Reed "Turbo" stoves with blowers?

Looking forward to the replies. Tom R, please forward this to the
Gasification List serve if those people should see it, but request that
replies get sent to the Stoves List serve.

Paul

>Re you call for assistance:
>
>1. Emissions testing. Must be scientific and rigorous, with appropriate
>quantification according to the variables of fuels and combustion
>chambers. You need to have the equipment and knowhow. We provide the
>stove(s) and info about the fuels.
>
>I put the question the Executive of REASWA today and they were interested to
>do the testing here at the Cemistry Department of the Kwaluseni campus. It
>is a real possibility that the equipment could be bought by the project and
>used only for our purposes, and if others want to have things tested the
>project would get income from its use (like R1000 per test?).
>
>2. Efficiency testing: Very similar to the above statement, but this is
>more closely linked to the issues of combustion chambers and the stove
>structures (placement of the pots to get higher efficiency).
>
>Ditto. No reason not to build capacity in the local university. It will
>certainly be cheaper that the USA and we can do a lot more of it.
>
>We (REASWA) have a project that requires testing inside houses as well as
>stoves so these things seem to fit together with great synchronicity.
>
>3. External examiners: We will seek an independent review periodically
>during the 3 years of the Shell grant.
>
>Seems we have located someone already.
>
>I liked the grid of options and relationships for examining the stove
>components.
>
>I have thought about implementation and schools that prepare a lot of food
>for lunch feeding schemes are ripe for testing purposes as they are many and
>malleable. They also use a great deal of fuel collected by students. We
>can get 'professional' opinions from the cooks too.
>
>I am likely to go ahead with the solar stove project with GTZ and this fits
>well with the manufacturing capacities that are required. I will get three
>samples from them in the next few days.
>
>I haven't lit a match since you were here as I am tooooo busy but money is
>at last rolling slowly. The pumps for Moz are under way at last - 100 of
>them.
>
>Nothing else at the moment. Glad to hear you are up and running again.
>
>Regards
>Crispin

Stoves List Moderators:
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From crispin at newdawn.sz Thu Apr 11 12:03:59 2002
From: crispin at newdawn.sz (Crispin)
Date: Tue Aug 31 21:37:45 2004
Subject: RAPS Technologies: engineer wanted
Message-ID: <000001c1e19c$1f167dc0$6de80fc4@home>

From: Doug Banks <doug@raps.co.za>
Sent: Thursday, April 11, 2002 9:04 AM
Subject: RAPS Technologies: engineer wanted

Dear friend/colleague

We are looking for someone really good (with excellent potential) to help
with the areas of work described below at RAPS. A short 'advert' follows.
There is more info on the web address given. If you can pass it on to the
right sort of person, I would really appreciate it.

Yours sincerely,

Doug Banks

ENGINEER - Product Development and Commercialisation

RAPS Technologies has an opportunity for a graduate engineer with
a Masters degree and/or at least two years of relevant experience to:
Join the project team, and ultimately manage the ongoing
development and commercialisation of an exciting new software
and hardware based Energy Services Management System that
assists utilities in the delivery of energy services to rural
areas.

Provide assistance to the technical management of an off-grid
utility in northern KwaZulu Natal currently implementing the
management system.

Participate in other consulting and implementation work in the
field of rural and renewable energy, and energy efficiency
projects.

For further information see the web site: www.raps.co.za/rapstech
Queries: info@raps.co.za

---
RAPS - Rural Area Power Solutions (Pty) Ltd
224 Loristo Street, Pretorius Park, Pretoria, RSA
P.O. Box 34921 Glenstantia 0010, RSA
Tel: +27 12 99 88 280 Fax: +27 12 99 88 401
email: doug@raps.co.za http://www.raps.co.za

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From tombreed at attbi.com Thu Apr 11 17:51:05 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:45 2004
Subject: Gasifier fundamental question
In-Reply-To: <4.3.1.2.20020411101646.00c77620@mail.ilstu.edu>
Message-ID: <002c01c1e1cd$0c24ad00$4bc0fd0c@TOMBREED>

Dear Paul, Crispin and All:

If you light the stove at the bottom and then pour on the fuel, in the first
2-3 minutes ALL the volatiles are driven off, much faster than you can
supply secondary combustion air to burn them cleanly.

If you light the stove at the TOP, the pyrolysis front moves downward in a
very regular manner, releasing the fuel at a constant rate (10 g/hr = 3 kW
for our stoves on high).

See attached graphs of our latest campstove attached, with efficiencies of
38-45%, and graph of water temp, weight of fuel remaining...

(Why are we discussing what we can so easily try?)

Yours truly, TOM REED
----- Original Message -----
From: "Paul S. Anderson" <psanders@ilstu.edu>
To: "New Dawn Engineering" <admin@newdawn.sz>
Cc: "Ron Larson" <ronallarson@qwest.net>; <tombreed@attbi.com>; "Apolinário
J Malawene" <ajmalawene01@hotmail.com>; "Bob and Karla Weldon"
<bobkarlaweldon@cs.com>; "Ed Francis" <cfranc@ilstu.edu>; "Tsamba--Alberto
Julio" <ajtsamba@zebra.uem.mz>; "Lily Coyle" <astrozen2000@hotmail.com>;
<stoves@crest.org>
Sent: Thursday, April 11, 2002 11:51 AM
Subject: Gasifier fundamental question

> Stovers (especially Tom and Ron)
>
> Crispin at New Dawn Engineering wrote to me:
> >Dear Paul
> ... (snip)
> >I wanted to see what people came
> >up with as a reason for burning from the top down. I am singularly
> >unimpressed with the reasoning. I suspect that it is a 'given' not to be
> >questioned. I am still waiting to hear ANY reasonable explanation for
not
> >smoking off the wood in any pattern or position. Charcoal is made by
> >running the smoke (from the charing process) through the uncharred wood.
> >Why should it be different with a stove??
> .....
>
> VERY sound statements. Now, what do the experts say?
>
> I can imagine that the issues of "fire present" versus "heat without fire,
> as in a retort" could be very important, especially for issues of control
> of the amount of gases being generated.
>
> I think we have a requirement of burning the gases soon after generation
> because we are dealing with SMALL stoves and POOR economic
> conditions. And that also might influence what is and is not possible
> with top lighting versus bottom lighting.
>
> IMPORTANT NOTE: It is not really "top" vs "bottom" because SOME
> gasifiers force the air downward through the fuel, making it the
equivalent
> of bottom lighting where the air flow is upward. Instead, the issue
> focuses on the air flow going AGAINST the direction of the pyrolysis
> front. Tom Reed called his stove the IDD (Inverted DownDraft gasifier)
> and many people do not like that expression, because it is really an
> UpDraft, BUT it is directed AGAINST the progression of the burning that
> comes downward from the top
>
> Therefore, when the draft and the progression of the burning are in the
> SAME direction, IS there control of the gasification process (as separate
> from the "burning" of the char after (or simultaneously with) the gases
> having been driven off?
>
> What this boils down to is this: How are the "against burn" draft and the
> "with burn" draft crucial with the gasification process as envisioned for
> the small-scale domestic household stoves such as the Juntos stoves or the
> Reed-Larson IDD stoves or even the Reed "Turbo" stoves with blowers?
>
> Looking forward to the replies. Tom R, please forward this to the
> Gasification List serve if those people should see it, but request that
> replies get sent to the Stoves List serve.
>
> Paul
>
>
>
>
>
>
> >Re you call for assistance:
> >
> >1. Emissions testing. Must be scientific and rigorous, with appropriate
> >quantification according to the variables of fuels and combustion
> >chambers. You need to have the equipment and knowhow. We provide the
> >stove(s) and info about the fuels.
> >
> >I put the question the Executive of REASWA today and they were interested
to
> >do the testing here at the Cemistry Department of the Kwaluseni campus.
It
> >is a real possibility that the equipment could be bought by the project
and
> >used only for our purposes, and if others want to have things tested the
> >project would get income from its use (like R1000 per test?).
> >
> >2. Efficiency testing: Very similar to the above statement, but this is
> >more closely linked to the issues of combustion chambers and the stove
> >structures (placement of the pots to get higher efficiency).
> >
> >Ditto. No reason not to build capacity in the local university. It will
> >certainly be cheaper that the USA and we can do a lot more of it.
> >
> >We (REASWA) have a project that requires testing inside houses as well as
> >stoves so these things seem to fit together with great synchronicity.
> >
> >3. External examiners: We will seek an independent review periodically
> >during the 3 years of the Shell grant.
> >
> >Seems we have located someone already.
> >
> >I liked the grid of options and relationships for examining the stove
> >components.
> >
> >I have thought about implementation and schools that prepare a lot of
food
> >for lunch feeding schemes are ripe for testing purposes as they are many
and
> >malleable. They also use a great deal of fuel collected by students. We
> >can get 'professional' opinions from the cooks too.
> >
> >I am likely to go ahead with the solar stove project with GTZ and this
fits
> >well with the manufacturing capacities that are required. I will get
three
> >samples from them in the next few days.
> >
> >I haven't lit a match since you were here as I am tooooo busy but money
is
> >at last rolling slowly. The pumps for Moz are under way at last - 100 of
> >them.
> >
> >Nothing else at the moment. Glad to hear you are up and running again.
> >
> >Regards
> >Crispin
>
> 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
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
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> -
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>
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>

Campstove - 8cm.xls

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From ronallarson at qwest.net Thu Apr 11 19:19:21 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:45 2004
Subject: Comments on Ft. Collins, Colorado
Message-ID: <000501c1e1d9$9668fbe0$20f86641@computer>

Stovers:

We don't hear a lot from Stuart
Conway on this list - but we should hear more. I cannot think of anyone on
the list who has the same niche as Stuart - who is the International Director of
Trees, Water & Paper. His niche in part is collaborating with (finding
funds for) others in worthy development projects. In the stoves
area, this collaboration has included work with Rogerio Miranda (Nicaragua)
and with the folks at Approvecho. His office contained a nice looking
Approvecho stove - that Stuart had made himself for use in talking to local
schools.

His office is very close to the
main campus of Colorado State University - a land grant college with an
excellent reputation in forestry and in working with developing
countries. The office had about a half-dozen volunteers in mailing
out their Spring newsletter (Forests Forever) when I got there for a too-short
visit. I recommend looking at the TWP web-<FONT face=Arial
size=2>site: <A
href="http://www.treeswaterpeople.org">www.treeswaterpeople.org

I also had a chance for another
too-short visit with a person Stuart has recruited to help do some stoves
testing as part of classroom work at CSU. The person is Professor Bryan
Willson - who is Research Director for the ME Department's Engines and Energy
Conversion Laboratory. Just now becoming a "stoves" member, Bryan has
quite a history of development work in West Africa. It appears that the
Approvecho stove will receive some testing this semester (as Bryan's
students have been previously busy with the (highly successful) emissions
cleanup of two-cycle engines (which are heavily used in many developing
countries - and which have been major polluters).

From ronallarson at qwest.net Fri Apr 12 02:41:02 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:45 2004
Subject: Gasifier fundamental question
In-Reply-To: <4.3.1.2.20020411101646.00c77620@mail.ilstu.edu>
Message-ID: <005801c1e217$47cfa400$f8f66641@computer>

Paul (cc stoves):

You said yesterday <address snip>:

I confess my own efforts to find a way of utilizing the waste gases from
charcoal making for cooking (see the bioenergy list - before there was a
stoves list) had only to do with capturing the waste heat - and that I tried
bottom lighting as well - before I understood the process. If anyone can
pull that (charcoal-making) off with bottom lighting and natural updraft, I
would be delighted to hear it. Look again at the period when Elsen Karstad
was first trying to convert sawdust. He was only able to flare with
downdraft and the equivalent of bottom lighting. Also look at the earliest
days of the stoves list, when there were claims that one couldn't even make
charcoal this way - as it hadn't ever been done with a down-draft version
(as we have heard of recently from Piet Verhaart (Australia). (Aside - I
have been trying to produce charcoal in a down-draft design, but so far
unsuccessfully)

In summary, one can make or avoid making charcoal in many ways - but I
have yet to see a clean flaring approach with natural updraft and bottom
lighting. (That last sentence designed to exclude the use of
externally-heated retort-canister approaches.)

> VERY sound statements. Now, what do the experts say?
>
(RWL2): Sorry, I totally disagree they are SOUND. I doubt very much
that Cripin has conducted a successful top-lit, updraft experiment. Paul -
have you tried your own juntos stove work with bottom lighting of the lowest
element? I predict it will totally fail - if your interest is in a clean,
controllable process. Certainly one can bottom light - almost everyone
does - but I have yet to see any stove that is anywhere near as clean or
controllable as a top-lit, charcoal-making, updraft design. What some on
this list see as a failure (having charcoal left over), is the exact reason
I went into the development of the stove. With persons all over the world
selling charcoal as a fuel to be preferred over wood (mainly because it is
cleaner burning) - I fail to understand the logic on why charcoal production
is a problem.

> I can imagine that the issues of "fire present" versus "heat without fire,
> as in a retort" could be very important, especially for issues of control
> of the amount of gases being generated.
>
(RWL3): Sorry - please clarify your intent here. I don't ever recall
this list using the phrase "fire present" or "heat without fire" -
especially in a stove context. Hopefully other parts of this response will
get at your intent here.

> I think we have a requirement of burning the gases soon after generation
> because we are dealing with SMALL stoves and POOR economic
> conditions. And that also might influence what is and is not possible
> with top lighting versus bottom lighting.
>
(RWL4): It (everything in the first sentence - the burning requirement,
small stoves, poor economic conditions) "might" have some influence on
something - but certainly top lighting should not be discarded for any of
those reasons. I have used only scrap materials for almost all my top-lit
stoves. There is nothing inherently requiring any precision (ie high cost)
that I am aware of. Tom Duke (Iowa) within weeks of the first discussions
on this topic six years ago built one successfully using only a shovel. His
second experiment used nothing except an old (and long) stove pipe - both
pyrolysing and burning for hours and successfully leaving behind the
valuable co-products of a heated barn and charcoal.

> IMPORTANT NOTE: It is not really "top" vs "bottom" because SOME
> gasifiers force the air downward through the fuel, making it the
equivalent
> of bottom lighting where the air flow is upward.

(RWL5): Aha - I think I have found some of your confusion. This last
sentence is totally wrong. The usual down draft has bottom lighting and the
air flow is of course downward (whence the name "downdraft"), while the
pyrolysis front (which is stationary) is moving counter to the downward
moving material (with carefully crafted conical bins and pyrolysis region
dimensions that ensure proper continuous (not batch) operation. Lots of
charcoal is produced in these downdraft operations and some is even found
useful for pyrolysis gas cleanup after suitable cooling. I worry also
about your use of the word "forced". Atmospheric pressure does the forcing,
as a lower pressure is maintained on the gases' way to the internal
combustion engine for which the gasifier is supplying the fuel. I believe
some carbon dioxide sneaks through in this downdraft process (along with
lots of N2) - whereas my measurements on the top-lit stove showed ZERO CO2
in the updraft version. I think this is mandatory, as the downdraft design
is trying to consume the charcoal and must have some left-over oxygen below
the pyrolysis region to accompish that. In the top-lit, updraft
charcoal-making stove, the upper layer of charcoal converts any uprising CO2
back to the desired combustible CO. Any lowered production of charcoal is
highly desirable by leading to the even more highly desired CO.

> Instead, the issue
> focuses on the air flow going AGAINST the direction of the pyrolysis
> front.

(RWL6): This is a dangerous sentence because in all downdraft gasifiers
(not updraft or downdraft charcoal makers) one must have a stationary
pyrolysis front with downward flowing material. (granted this is equivalent
in relativistic terms). In an updraft gasifier, the flow of material is
also downwards, and the pyrolysis front is stationary, but the resulting
pyrolysis gases (drawn off of course at the top) now have considerable CO2
content along with the still valuable pyrolysis gases driven out of the wood
by the rising hot combustion (CO2) gases.

>Tom Reed called his stove the IDD (Inverted DownDraft gasifier)
> and many people do not like that expression, because it is really an
> UpDraft, BUT it is directed AGAINST the progression of the burning that
> comes downward from the top
>

(RWL7): I hate to be picky, but there is no "burning that comes downward
from the top". The pyrolysis front has chemical reactions that I feel
should not be called "burning". This is a relatively low temperature region
with not much energy release. I urge replacing your "burning" with the term
"pyrolysis". I understand Tom's desire to use "IDD", but I don't like it
for reasons other than that it is updraft. Only a few highly trained people
like Tom and Agua Das (I know no others on this list, and certainly not me)
understand the highly delicate and complicated downdraft gasifier principles
(in my opinion, the reason you see so few in use). Then when you compound
that with the term "inverted", you are guaranteed to have close to zero
comprehension of what is basically a simple process - pyrolysis in one
place - and close-coupled clean combustion a few cms away - all done with
natural convection. Tom's use of blowers to achieve pre-mixing and a blue
flame is an outgrowth of what is needed in (either updraft or down draft)
gasifiers - not what is needed in stoves (and I am not disparaging the use
of blowers - they have advantages).

> Therefore, when the draft and the progression of the burning are in the
> SAME direction, IS there control of the gasification process (as separate
> from the "burning" of the char after (or simultaneously with) the gases
> having been driven off?

(RWL8) Sorry - but again I am not sure of the question. Let me try
two definitive statements that might get at your question.

1). In gasification, one can do either updraft or downdraft design - both
with stationary pyrolysis regions and downward moving fuels - and the power
output is controllable by changing the primary airflow - either by changing
blower speeds or fuel stack height - and a relatively small amount of
charcoal is produced. The downdraft design gives a higher quality gas.

2) In pyrolysis-based stoves, the top-lit updraft design allows fine control
through control of the (very low volume) primary air supply and batch
loading; bottom lighting still entails pyrolysis reactions and eliminates
the batch-loading restriction, but allows output control only through fuel
loading and complete combustion is essentially impossible. There has been
essentially no work on a downdraft stove design with controllable primary
air (which would permit pyrolysis).

Aside - a batch gasifier for generator applications is essentially
worthless - at least in a modern fast-paced society. A batch stove is not
as desirable as one capable of feeding additional fuels - but at least some
think it can be tolerated if it brings other advantages to the table (such
as much cleaner combustion, controllability, high efficiency, and a saleable
co-product).

>
> What this boils down to is this: How are the "against burn" draft and the
> "with burn" draft crucial with the gasification process as envisioned for
> the small-scale domestic household stoves such as the Juntos stoves or the
> Reed-Larson IDD stoves or even the Reed "Turbo" stoves with blowers?
>

(RWL9) Again we have the terminology problems already stated above.
Limiting myself to updraft stoves (which includes all three of those at the
end of your question) , the term "top-lit" (which I think is the same as
your "against burn") I contend is absolutely crucial if one wants very clean
combustion and a controllable flame (controllable because air supply is
subdivided into two parts). If you move to the standard "bottom-lit" (I
think the same as your "with burn" designator"), you gain the advantage of
being able to prolong the cooking period at will, but you lose all
controllability (partially alleviated with constant tending), with much less
complete combustion (a dirtier output), and lower overall efficiency as an
optimum air supply CANNOT (at least I have never seen any claim or attempt
to do so) be achieved through fuel supply control alone.

Aside - the secondary air supply for top-lit stoves has not seemed to
need a separate control, as there seems to be approximately the correct
"feed-back" control built into the changing internal pressure conditions as
power level changes (where we have been calling this "turn-down" ratio).
But there has still been nowhere near enough technical study of the top-lit,
natural convection charcoal-making stove - maybe we will find that secondary
air control is also desirable.

Summary - I hope I have not left many more confused than before. I
repeat that I think there are huge differences in where one does the
lighting - and all are also directly related to the splitting of the air
supply into two components. I accept that striving for controllability and
clean combustion brings some down-sides - but I reject that high cost is one
of them. I contend that the advantages to the user of much less time spent
in fire tending, a much cleaner kitchen, the reduction in traditional
charcoal making and a saleable co-product MIGHT offset the batch nature,
some problemsin capuring the charcoal after cooking, and the need for some
new education in fire tending.

Going back to Cripin's last sentence in the opening paragraph - people do
not now make charcoal in the traditional (ie non-flaring) manner anywhere
near their kitchens. If we started paying more attention to doing that
charcoal-making job right (sustainably, as opposed to prohibiting it), I
predict we would soon see charcoal-making stoves everywhere. That is why
some of us continue to talk a lot about pyrolysis and split air supplies on
this list. I'd like to hear from both Paul and Crispin (and anyone else)
on which part of my argument failed to make sense.

> Looking forward to the replies. Tom R, please forward this to the
> Gasification List serve if those people should see it, but request that
> replies get sent to the Stoves List serve.
>
> Paul
>
>
<Snip a further reply from Crispin on non-directional topics that seem
unrelated to the first question posed by Paul to Tom Reed and myself>.

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From pverhaart at optusnet.com.au Fri Apr 12 02:43:48 2002
From: pverhaart at optusnet.com.au (Peter Verhaart)
Date: Tue Aug 31 21:37:45 2004
Subject: Fwd: Re: Gasifier fundamental question
Message-ID: <5.1.0.14.2.20020412214254.00a13e20@mail.optusnet.com.au>

>Date: Fri, 12 Apr 2002 21:41:01 +1000
>To: "Paul S. Anderson" <psanders@ilstu.edu>
>From: Peter Verhaart <pverhaart@optusnet.com.au>
>Subject: Re: Gasifier fundamental question
>
>At 12:51 11/04/02 -0500, you wrote:
>>Stovers (especially Tom and Ron)
>>
>>Crispin at New Dawn Engineering wrote to me:
>>>Dear Paul
>>... (snip)
>>>I wanted to see what people came
>>>up with as a reason for burning from the top down. I am singularly
>>>unimpressed with the reasoning. I suspect that it is a 'given' not to be
>>>questioned. I am still waiting to hear ANY reasonable explanation for not
>>>smoking off the wood in any pattern or position. Charcoal is made by
>>>running the smoke (from the charing process) through the uncharred wood.
>>>Why should it be different with a stove??
>
>
>Top down burning does not expose the lower layers of fuel to heat so there
>is less uncontrolable evolution of volatiles. Cleaner burning.
>Bottom up burning does expose all of the fuel above the combustion zone to
>heat leading to copious production of volatiles nobody knows how to get
>rid of except via a chimney which transports the smoke to the neighbours.
>
>Piet

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From dstill at epud.net Fri Apr 12 21:21:52 2002
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:37:45 2004
Subject: Shaping the top of the single pot cooking stove
Message-ID: <000c01c1e2cd$5bacaa20$241d66ce@default>

Dear Friends,

For many years, Larry has been reminding his students at Aprovecho that hot
flue gases need to scrape against pot surfaces for efficient heat transfer.
This is true when using one pot on top of a fire. Larry likes to taper the
gap between the top of the stove and the pot, keeping the same cross
sectional area. In other words, if there is an inch gap directly under the
center of the pot then the gap gradually decreases until it is very small
under the outer rim, say around 3/16" or so, depending on pot size... This
is a useful design characteristic!!!

If the gap under the pot stays constant a lot of heat escapes that could be
heating food. Today, I did a couple of experiments using a 12" in diameter
griddle called a comal used for making tortillas in Mexico. Three type k
thermocouples were placed in the middle (1) and the two opposite and
furthermost edges (2,3) of the steel comal. When the gap was correctly
formed into a diminishing taper to the outer edges there was about a 70
degree F. difference (at 440 degrees F) between the warmest (middle) and
coldest sensor. But when the taper was removed and the gap increased to
7/16" under the edges of the comal the difference in temperature more than
doubled. I chose to measure the difference at 440 degrees F. because I've
read that tortillas cook best at between 440 to 480 F.

I'll fool around with the gap some more but for now it seems that Larry's
rule of keeping the same cross sectional area under the pot and creating a
gradual, smooth curve from vertical to horizontal flow is quite beneficial.

How much fuel does it take to make tortillas in a Rocket stove? Well, I made
thin corn tortillas like we use for tacos. It took about a pound of wood to
make about a kilo of finished tortillas, burning about four 1/2" in diameter
sticks at a time, pushed into the fire as they were consumed. Four sticks
kept the center of the comal around the optimal temperature and eventually I
was making three at a time using the whole surface. I'll continue playing
around with comals, tortillas, and gaps and present a paper at the next
ETHOS meeting. Heck, I'll make everybody tacos!

Best,

Dean

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From crispin at newdawn.sz Fri Apr 12 21:24:21 2002
From: crispin at newdawn.sz (Crispin)
Date: Tue Aug 31 21:37:45 2004
Subject: Gasifier fundamental question
Message-ID: <002501c1e2b3$8fc59ac0$52e80fc4@home>

Dear Paul and All

First:
I wrote to Paul: "I am still waiting to hear ANY reasonable explanation for
not smoking off the wood in any pattern or position."

This followed the discussions and experiments we had together a few weeks
ago in Swaziland. Paul brought a few small gasifying stoves with him and we
lit a couple on my (cement) veranda.

We tried one with chopped wood and it flamed very nicely. Clean, hardly any
visible emissions after the flame was established (don't think it doesn't
smoke at all - it smokes at the beginning and a lot at the end).

When it burned down to charcoal, at which time it smoked profusely, I added
more chopped wood on top. It went out. Next time I added it just before
the pyrolysis stopped and it re-established itself as a gasifying stove.
This gassing and flaming continued as the new fuel (added on top of the hot
charcoal which remained at the bottom) pyrolysed to produce gas in the
regular way, though it no longer had a top-down flame front. It was hot
here and there.

It was top-lit to begin with and bottom lit for refueling and middle lit
during the second burn.

I have been reading for 6 months on this list that this cannot be done and
doesn't work and gives off uncontrollable amounts of gas. Paul told me just
before we did it that it wouldn't work, but Paul also taught me to try and
see just for the heck of it, so I did.

Refuelling works very nicely with regular wood. Perhaps it won't work with
pelletized wood.

Second:
I feel there are some apples mixed in with the oranges. Ron wrote,
"Charcoal is indeed made in the way Crispin describes. Unfortunately, it is
one of the most abominable practices on the face of the earth..."

Well...yes it is when done to produce charcoal from wood in a forest, but we
are not doing that. The significant difference is that in the stove we are
not burning wet wood. This is an important consideration. A number of the
complaints about the process and the chemical analyses discussed for
emissions and flamability of the gasses are made with reference to wet wood
in a forest, not dry wood in a stove. In other words some of the arguments
presented against bottom lighting a gassifying stove are based on an
analysis of wet wood charcoal production.

Tom recommends that the fuel be "...0-25% moisture content...". That is not
the condition in a forest-based charcoal production so to be useful we
should limit the discussion of charcoal making stoves to forseeable
conditions in a stove.

On Apr 03 Tom wrote, "...gasifiers burn at a VERY constant rate until the
volatiles are gone...".

This is a very important point and one that can be considered essential in
certain cooking applications. However constancy is not a good thing if you
want to vary the output of heat because once it is going I have found
gassifying stoves to be quite difficult to control vis-a-vis the heat
output. Getting high heat is difficult. It is very important to keep in
mind that there is zero hope of us in the field getting the fuel Tom is
using to achieve this constant heat output. The experiment, if I may call
it that, is burning unobtanium.

The heat requirement in our area is for a lot of heat at the beginning
followed by a significant turndown and a long simmer. This can be achieved
by lighting up a relatively large amount of gasses followed by a relatively
small amount after 20-30 minutes. This is approximately what happens if you
bottom light a charcoaling stove, according to Tom recent message with the
Camp Stove data attached. Tom's statement that the gas cannot be burned
effectively because of a lack of air being available immediately after
adding fuel to an operating stove is conditioned upon a certain stove
design, not something inherent in the making of gasses and charcoal.
Perhaps this observation could be rephrased as, "If you add fuel to an
operating IDD stove, there will initially be a large amount of gas
produced." The ability of the stove to burn it effectively is a different
matter and does not limit the type of stove you might construct.

I have not observed the gassing phenomenon Tom describes using chopped wood.
One reason for that may be the smaller surface-to-volume ratio of the wood
compared with the pellets.

Third:
It is important to me to know if Ron's statement, "The problem is that the
valuable combustible gases that are released are so diluted by carbon
dioxide and water content that it is not combustible when emitted from
traditional (or even improved) charcoal kilns." holds true for stove-based
gas production. Am I right in observing that this is only a problem when
working with wet wood in a forest? By forest I am thinking of a
batch-process stacked log charcoaling operation.

I have a chemistry question. If I were to charcoal a small amount of dry
wood in a stove, and produced the aforementioned high CO2 gasses, is that
not OK in that all I want is the heat, after all I am trying to cook here.
I am not particularly after CO.

I cannot yet grasp the difference between having, on the one hand, the
gasses mostly burned lower in the stove to CO2 and then burning off the
remaining CO with preheated secondary air and on the other hand, carefully
tinkering with the pyrolyzing zone to produce more CO and then burning it to
CO2 slightly higher in the stove. The end result is (hopefully) CO2 in both
cases. The amount of heat released is the same. Why all this concern for
intermediate gas quality?

Fourth:
Ron mentioned "...the period when Elsen Karstad was first trying to convert
sawdust. He was only able to flare with downdraft and the equivalent of
bottom lighting." This is interesting but might have been for a number of
reasons not applicable to our stoves. Was he using preheated secondary air?
If not, I am not surprised he had problems. Was he using preheated primary
air? That also might have helped a great deal.

Ron very reasonable asks, "With persons all over the world selling charcoal
as a fuel to be preferred over wood (mainly because it is cleaner burning) -
I fail to understand the logic on why charcoal production is a problem."

I don't see it as a problem per se, but I see it more as a non-issue, in
other words, not something worth chasing as a 'needed element' of a wood
stove. It does seem to be chucked in as an end in itself or an essential
feature. I can't imagine a better use for the charcoal than to leave it
where it is in the stove and burn it before it needs to be reheated to get
going. If the gassifying process is as clean as is claimed, and the burning
of charcoal is as clean as is claimed, why not just burn both the gasses and
the charcoal at the same time?

I fully agree with Ron that, "There is nothing inherently requiring any
precision (ie high cost) that I am aware of." Agreed. The 'stoves' Paul
has been making cost a few cents.

Fifth:
I am very interested in this: "In the top-lit, updraft charcoal-making
stove, the upper layer of charcoal converts any uprising CO2 back to the
desired combustible CO." I understand from previous submissions that this
process is highly endothermic and also that it reduced charcoal production.
True? Or perhaps is the charcoal carbon being liberated. To be very clear,
is the uprising CO2 knocking C off the charcoal to make CO, or is the CO2
being 'converted' back to CO leaving the charcoal unmodified?

Sixth:
Ron wrote, "In an updraft gasifier, the flow of material is also downwards,
and the pyrolysis front is stationary, but the resulting pyrolysis gases
(drawn off of course at the top) now have considerable CO2 content along
with the still valuable pyrolysis gases driven out of the wood
by the rising hot combustion (CO2) gases."

I understand this, but as with the forest charcoal production, this is not
directly applicable. We are not actually trying to produce wood-gas, we are
trying to cook or produce heat. Whether the heat is produced lower in the
stove or higher is a 'clean blue flame' is not important as the net effect
(if final gasses and heat) is the same.

The arguments proffered for the various combinations of stove layouts have
not satisified me on this point. Yes, one can tinker with the relative gas
ratios, and yes there are analogies in other gas and fire processes, but
they are not 100% related to the task at hand.

How can I say that? Well, one of the widely discussed limitations on stove
design, based on these theoretical and analagous arguments, is that you
cannot make a really clean fire using wood with bottom firing. Yet David
Hancock did it years ago with a production stove.

Another conclusion is that top-lit updraft gassifying stoves cannot be
refuelled. Now this is a very important claim because now we have Paul
building stoves that have slide-out containers so he can try to get the
charcoal out and reload the stove to continue cooking his porridge. Yet the
first time I tried refuelling with Paul's cheesy 10 cent top-lighting
updraft stove it worked very well.

Gentlemen and women, this is serious stuff. Why are workable designs being
ruled out? What am I missing here? It seems to me that features and
effects particular to individual stove layouts and fuels are being projected
onto stoves in general.

Seventh
I want to highlight the following by Ron in his 7th comment
>(RWL7): I hate to be picky, but there is no "burning that
>comes downward from the top". The pyrolysis front has
>chemical reactions that I feel should not be called "burning".

In our discussions in Swaziland, Paul and I had a problem trying to describe
this because if we call the pyrolyzing zone 'primary combustion' (there is
in fact some combustion) then we have above it a 'secondary combustion' zone
where the gasses are reacted with oxygen. Those unburned or partially
reacted gasses like CO which remain, can be burned in a zone above that and
we settled on 'tertiary combustion' for obvious reasons.

In an open wood fire these three combustions are in fact going on. The
gasses sprout from the wood (all wood fires are gas-producing), they are
burned and above that (in a Basintuthu stove for example) the combustion
products are reacted with hot 'secondary' air. There seems to be at least
some confusion about the terms 'primary combustion' and 'secondary
combustion' which are worthy of resolution. Air is provided to make the
charcoal. That is primary air. Air provided to burn the gasses higher up
will properly be called secondary air. Pre-heated air provided to react the
still remaining fuel gasses should then be called 'tertiary air'. While
unconventional, I don't see any way around this. The fact that people seem
not to be providing for tertiary combustion does not mean that it is not
required or would not clean up the emissions even further.

Eighth:
I fully believe Ron's statement, "The downdraft design gives a higher
quality gas." The thing is, we are not after producing gas, we are
producing heat for cooking and the quality of the gas is not important
unless it will not react with hot secondary air.

I do not agree with the statement, "...bottom lighting still entails
pyrolysis reactions and eliminates the batch-loading restriction, but allows
output control only through fuel
loading and complete combustion is essentially impossible."(RWL8)

Bottom lit stoves can be controlled by restricting the primary air which in
the extreme position, turns it into a gassifying stove. I don't think there
is any essential or net difference between burning wood to make a gas to be
burned nearby and burning wood to make gasses to be burned in the immediate
vincinity. If it all goes to CO2 and water, heat is heat.

"...the secondary air supply for top-lit stoves has not seemed to need a
separate control..."

That is something Paul and I are investigating.

Many thanks for all the energy contributors spend adding fuel to this fire!

Regards
Crispin

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From andrew.heggie at dtn.ntl.com Sat Apr 13 12:26:06 2002
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <002501c1e2b3$8fc59ac0$52e80fc4@home>
Message-ID: <q48hbu4op62rdh0ld8poiaiqmb2b82t16r@4ax.com>

On Sat, 13 Apr 2002 08:21:28 +0200, "Crispin" <crispin@newdawn.sz>
wrote:

>First:
>I wrote to Paul: "I am still waiting to hear ANY reasonable explanation for
>not smoking off the wood in any pattern or position."

Well for my first I will say I have now met or talked to 5 posters to
the list and one lurker, all but one have been both helpful and
honourable, so I would say contributions are likely to be designed to
be helpful. Ambiguities and wrong interpretation can arise. I think
Ronal, though correct about venting of pyrolysis products, got the
wrong end of the stick.

Second I agree with Peter Verhaart.

>
>It was top-lit to begin with and bottom lit for refueling and middle lit
>during the second burn.

Which is fine, top lighting conveys an advantage in itself, that is
making the pyrolysis products all pass through the flame, this gives
both an opportunity for them to reach a high temperature and an
ignition source.
>
>I have been reading for 6 months on this list that this cannot be done and
>doesn't work and gives off uncontrollable amounts of gas. Paul told me just
>before we did it that it wouldn't work, but Paul also taught me to try and
>see just for the heck of it, so I did.

I must have missed this, we have discussed updraught burning and
adding fresh fuel to top lit stoves in the past, the problems arise
when too much is added causing the local fuel:air ratio to take an
excursion beyond that which will hold a flame, this extinguishes the
flame even though the stove continues to generate pyrolysis gas.
>
>Refuelling works very nicely with regular wood. Perhaps it won't work with
>pelletized wood.

It works fine with pelletised wood in a top stoked pellet stove as
well as in an idd stove, subject to amounts.
>
>Second:
>I feel there are some apples mixed in with the oranges. Ron wrote,
>"Charcoal is indeed made in the way Crispin describes. Unfortunately, it is
>one of the most abominable practices on the face of the earth..."

Ronal's misunderstanding of your statement I believe.
>
>Well...yes it is when done to produce charcoal from wood in a forest, but we
>are not doing that. The significant difference is that in the stove we are
>not burning wet wood.

It is possible though, with top lighting and stoking if dry kindling
is used as a starter. A number of the list can vouch for this,
including the lurker who has scaled up and implemented a lightly
forced
draught device based on my design, CO down to 150ppm at >50kW(t)
burning freshly cut hazel chips.

>This is an important consideration. A number of the
>complaints about the process and the chemical analyses discussed for
>emissions and flamability of the gasses are made with reference to wet wood
>in a forest, not dry wood in a stove. In other words some of the arguments
>presented against bottom lighting a gassifying stove are based on an
>analysis of wet wood charcoal production.

I do not believe you are correct to draw this inference.
>
>Tom recommends that the fuel be "...0-25% moisture content...". That is not
>the condition in a forest-based charcoal production so to be useful we
>should limit the discussion of charcoal making stoves to forseeable
>conditions in a stove.

Let's leave charcoal making out of this for the moment, I did not
think you meant this in your apparently private e-mail which was
quoted on list, poor netiquette that.
>
>On Apr 03 Tom wrote, "...gasifiers burn at a VERY constant rate until the
>volatiles are gone...".
>
>This is a very important point

Indeed, to my mind it is a very important point, it allows the air
supplies to be treated in a simple manner, akin to controlling fuel
and air together, I think however it is but one special case of top
down burning.

>and one that can be considered essential in
>certain cooking applications. However constancy is not a good thing if you
>want to vary the output of heat because once it is going I have found
>gassifying stoves to be quite difficult to control vis-a-vis the heat
>output. Getting high heat is difficult.

I can see this, there is little positive feedback as in a bottom lit
design, high heat is available with forced convection though.

> It is very important to keep in
>mind that there is zero hope of us in the field getting the fuel Tom is
>using to achieve this constant heat output. The experiment, if I may call
>it that, is burning unobtanium.

Very good point, pellet fuel is a developed world waste disposal
solution at present.
>
>The heat requirement in our area is for a lot of heat at the beginning
>followed by a significant turndown and a long simmer. This can be achieved
>by lighting up a relatively large amount of gasses followed by a relatively
>small amount after 20-30 minutes. This is approximately what happens if you
>bottom light a charcoaling stove, according to Tom recent message with the
>Camp Stove data attached. Tom's statement that the gas cannot be burned
>effectively because of a lack of air being available immediately after
>adding fuel to an operating stove is conditioned upon a certain stove
>design, not something inherent in the making of gasses and charcoal.
>Perhaps this observation could be rephrased as, "If you add fuel to an
>operating IDD stove, there will initially be a large amount of gas
>produced." The ability of the stove to burn it effectively is a different
>matter and does not limit the type of stove you might construct.

I can live with that idea, there are a number of ways of adding fuel
to a top lit device without causing snuffing problems even without
resorting to under stoking.
>
>I have not observed the gassing phenomenon Tom describes using chopped wood.
>One reason for that may be the smaller surface-to-volume ratio of the wood
>compared with the pellets.

Pass on that, I may not have noticed the post.
>
>Third:
>It is important to me to know if Ron's statement, "The problem is that the
>valuable combustible gases that are released are so diluted by carbon
>dioxide and water content that it is not combustible when emitted from
>traditional (or even improved) charcoal kilns." holds true for stove-based
>gas production. Am I right in observing that this is only a problem when
>working with wet wood in a forest? By forest I am thinking of a
>batch-process stacked log charcoaling operation.

It certainly is a fact that if the cv of the offgas is diluted it will
reach a point where it will not support combustion, this dilution
could be by other combustion products, water or excess air, this is
why a fire will just smoulder, the air:carbon reaction will slowly
continue without strictures of air:fuel ratios, the offgas will not
ignite in either the absence of a flame, wrong air:gas ratio or low
temperature (from low cv of the total mass flow).
>
>I have a chemistry question. If I were to charcoal a small amount of dry
>wood in a stove, and produced the aforementioned high CO2 gasses, is that
>not OK in that all I want is the heat, after all I am trying to cook here.
>I am not particularly after CO.

Yes in retaining the carbon unburnt you are not releasing all the fuel
value of the wood, but did you mean high CO2 or high CO?
>
>I cannot yet grasp the difference between having, on the one hand, the
>gasses mostly burned lower in the stove to CO2 and then burning off the
>remaining CO with preheated secondary air and on the other hand, carefully
>tinkering with the pyrolyzing zone to produce more CO and then burning it to
>CO2 slightly higher in the stove. The end result is (hopefully) CO2 in both
>cases. The amount of heat released is the same. Why all this concern for
>intermediate gas quality?

I once saw a list of benefits of the gasification on one of the CRESt
list, I cannot remember it, but controllability is one of them, In any
case I think you are surmising the enthalpy of the gases in the two
systems will be the same, in practice this will not be the case
because of losses low down in the stove, CO generation will take place
at 1100C, CO2 generation ~2000C, with both columns of gas rising which
one has the highest propensity to lose heat?

In any case Alex English posted figures to suggest that the idd
pyrolysis front is probably not a good CO generator, the major
advantage of the idd offgas is that primary air is kept very low, heat
losses at the front are low and the offgas has not been diluted by
much nitrogen. The offgas is of similar cv to that from a retort
system and hence burns cleanly when secondary air is added.
>
>Fourth:
>Ron mentioned "...the period when Elsen Karstad was first trying to convert
>sawdust. He was only able to flare with downdraft and the equivalent of
>bottom lighting." This is interesting but might have been for a number of
>reasons not applicable to our stoves. Was he using preheated secondary air?
>If not, I am not surprised he had problems. Was he using preheated primary
>air? That also might have helped a great deal.

I do not see any references to preheating air, ELK will answer this.
My understanding is that it is primarily a pragmatic solution to a
waste problem in the presence of a market for charcoal briquettes, ELK
has not suggested it is efficient use of fuel.
>
>Ron very reasonable asks, "With persons all over the world selling charcoal
>as a fuel to be preferred over wood (mainly because it is cleaner burning) -
>I fail to understand the logic on why charcoal production is a problem."

The point being that wood can be cleanly burnt, in the face of this
people ought to be able to cook with wood. If cultural needs dictate
that cooking is done with charcoal then the charcoal should and can be
made in an environmentally sound manner, hopefully using the waste
energy in the offgas at the same time.
>
>I don't see it as a problem per se, but I see it more as a non-issue, in
>other words, not something worth chasing as a 'needed element' of a wood
>stove.

I agree, I do not see charcoal production from a cooking stove to be
an advantage per se.

> It does seem to be chucked in as an end in itself or an essential
>feature. I can't imagine a better use for the charcoal than to leave it
>where it is in the stove and burn it before it needs to be reheated to get
>going. If the gassifying process is as clean as is claimed, and the burning
>of charcoal is as clean as is claimed, why not just burn both the gasses and
>the charcoal at the same time?

Yes, however even commercial sized gasification units seem to discard
char with the ash, it's inevitable really as chemical reactions tend
to equilibriums, if you supply just the 1kg of air needed to gasify
1kg of dry biomass then some will react all the way to produce H2O and
CO2, hence some char must be left. In a simple stove we can add excess
air above the 6kg needed for stoichiomentric conditions, this allows
unreacted O2 to leave the system rather than unreacted C.
>
>I fully agree with Ron that, "There is nothing inherently requiring any
>precision (ie high cost) that I am aware of." Agreed. The 'stoves' Paul
>has been making cost a few cents.
>
>Fifth:
>I am very interested in this: "In the top-lit, updraft charcoal-making
>stove, the upper layer of charcoal converts any uprising CO2 back to the
>desired combustible CO."

Who said that? Tom Reed has previously said that to get to an
equilibriom where most of the carbon has reacted to CO requires a
temperature of >700C maintained through a bed of coals at least 20
particle diameters deep, I do not believe this equilibrium is
approached in a natural draught idd stove.

>I understand from previous submissions that this
>process is highly endothermic and also that it reduced charcoal production.

Intuitlivel if you increase production of CO or CO2 you must reduce
yield of char.

>True? Or perhaps is the charcoal carbon being liberated. To be very clear,
>is the uprising CO2 knocking C off the charcoal to make CO, or is the CO2
>being 'converted' back to CO leaving the charcoal unmodified?

My understanding which I have posted a number of times inviting
responses is:

1) At fairly low temperature ~200C an oxygen molecule dissaciates by
surface adsorption onto the carbon. O2 disocaition very mildly
endothermic.

2) CO is generated, strongly exothermic.

3) This CO immediately reacts with incoming oxygen to CO2, stongly
exothermic

4) in passing away from the reaction site if this CO2 has both high
enough temperature and residence time in contact with carbon it
reduces to CO, strongly endothermic.

3 and 4 cancel out, 2 exceeds 1 so overal CO production is exothermic.
>
>Sixth:
>Ron wrote, "In an updraft gasifier, the flow of material is also downwards,
>and the pyrolysis front is stationary, but the resulting pyrolysis gases
>(drawn off of course at the top) now have considerable CO2 content along
>with the still valuable pyrolysis gases driven out of the wood
>by the rising hot combustion (CO2) gases."
>
>I understand this, but as with the forest charcoal production, this is not
>directly applicable. We are not actually trying to produce wood-gas, we are
>trying to cook or produce heat. Whether the heat is produced lower in the
>stove or higher is a 'clean blue flame' is not important as the net effect
>(if final gasses and heat) is the same.

True if the overall combustion is equally clean. I have tinkered with
all sorts of burning, toplit top down burning has given me the
cleanest results, demonstrably so in the device recently built and
tested by one of this list to my initial design.
>
>The arguments proffered for the various combinations of stove layouts have
>not satisified me on this point. Yes, one can tinker with the relative gas
>ratios, and yes there are analogies in other gas and fire processes, but
>they are not 100% related to the task at hand.
>
>How can I say that? Well, one of the widely discussed limitations on stove
>design, based on these theoretical and analagous arguments, is that you
>cannot make a really clean fire using wood with bottom firing. Yet David
>Hancock did it years ago with a production stove.

Again I do not believe this has been claimed, Dean Still has a clean
burning updraught, bottom lit device. IDD and top lighting and top
down lighting have been put forward as tools to get a result, no one
has claimed they are the only way. They are relatively new concepts in
relation to humanities use of wood cooking, and as a result are novel
to many.
>
>Another conclusion is that top-lit updraft gassifying stoves cannot be
>refuelled.

Not so at all, I can remember posting about this way back as well as
in one of the coal cooking threads, I recall Ronal posting on it also.

>Now this is a very important claim because now we have Paul
>building stoves that have slide-out containers so he can try to get the
>charcoal out and reload the stove to continue cooking his porridge. Yet the
>first time I tried refuelling with Paul's cheesy 10 cent top-lighting
>updraft stove it worked very well.

Good.
>
>Gentlemen and women, this is serious stuff. Why are workable designs being
>ruled out?

They are not.

> What am I missing here?

Pass, I just take the view you can take the horse to water but you
cannot make it drink ;-).

>It seems to me that features and
>effects particular to individual stove layouts and fuels are being projected
>onto stoves in general.
>
>Seventh
>I want to highlight the following by Ron in his 7th comment
>>(RWL7): I hate to be picky, but there is no "burning that
>>comes downward from the top". The pyrolysis front has
>>chemical reactions that I feel should not be called "burning".

I think this is mistaken, I take burning to be an oxydation type
reaction, I do believe combustion can take place without flame, by
simple defintion.
>
>In our discussions in Swaziland, Paul and I had a problem trying to describe
>this because if we call the pyrolyzing zone 'primary combustion' (there is
>in fact some combustion)

Yes, but you can also have pyrolysis without combustion, as in a
retort.

> then we have above it a 'secondary combustion' zone
>where the gasses are reacted with oxygen. Those unburned or partially
>reacted gasses like CO which remain, can be burned in a zone above that and
>we settled on 'tertiary combustion' for obvious reasons.

As have many other combustion engineers in the past, in fact in large
furnaces many later stages of air addition are used between heat
removal stages to reduce formation of NOx.
>
>In an open wood fire these three combustions are in fact going on. The
>gasses sprout from the wood (all wood fires are gas-producing), they are
>burned and above that (in a Basintuthu stove for example) the combustion
>products are reacted with hot 'secondary' air. There seems to be at least
>some confusion about the terms 'primary combustion' and 'secondary
>combustion' which are worthy of resolution. Air is provided to make the
>charcoal. That is primary air.

Not quite, these terms originated in coal burning, coal is low in
volatiles and high in C, primary air refers to the air to gasify the
carbon, wheter it be to CO2 or CO, pyrolysis products are produced
when the heat of primary combustiion releases them.

> Air provided to burn the gasses higher up
>will properly be called secondary air.

> Pre-heated air provided to react the
>still remaining fuel gasses should then be called 'tertiary air'.

Fair enough

> While
>unconventional, I don't see any way around this. The fact that people seem
>not to be providing for tertiary combustion does not mean that it is not
>required or would not clean up the emissions even further.

Technically it would still be secondary combustion though.
>
>Eighth:
>I fully believe Ron's statement, "The downdraft design gives a higher
>quality gas." The thing is, we are not after producing gas, we are
>producing heat for cooking and the quality of the gas is not important
>unless it will not react with hot secondary air.

Yes

>
>I do not agree with the statement, "...bottom lighting still entails
>pyrolysis reactions and eliminates the batch-loading restriction, but allows
>output control only through fuel
>loading and complete combustion is essentially impossible."(RWL8)

It's true up to the stage that secondary combustion is established.
>
>Bottom lit stoves can be controlled by restricting the primary air which in
>the extreme position, turns it into a gassifying stove.

This can be true of bottom, mid or toplit.

> I don't think there
>is any essential or net difference between burning wood to make a gas to be
>burned nearby and burning wood to make gasses to be burned in the immediate
>vincinity. If it all goes to CO2 and water, heat is heat.

Yes as long as the conditions are such that combustion is complete and
the heat is liberated where it can be utilised.
>
>"...the secondary air supply for top-lit stoves has not seemed to need a
>separate control..."
>
>That is something Paul and I are investigating.

It is also a function of the earlier statement that offgas from an idd
stove is realtively constant, it is not true when a toplit stove is
allowed to turn into an updraught stove. I think there is some
confusion between top lit and idd.

AJH

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From harrick at sinfo.net Sat Apr 13 12:31:15 2002
From: harrick at sinfo.net (BHarrick)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <002501c1e2b3$8fc59ac0$52e80fc4@home>
Message-ID: <00bd01c1e332$30ae3e00$0f00000a@beatriz>

please change my email to:
harrick01@cwpanama.net

I would like if you can post a request for Hal Moore to write me.
Thanks,
Beatriz Harrick

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From psanders at ilstu.edu Sat Apr 13 12:52:22 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <002501c1e2b3$8fc59ac0$52e80fc4@home>
Message-ID: <4.3.1.2.20020413163522.0186ca60@mail.ilstu.edu>

Stovers,

Crispin wrote, and I emphasize:::::::

>Many thanks for all the energy contributors spend adding fuel to this fire!

And that includes Crispin messages, too.

Short Notes from Paul:

1. Ron correctly notes that MY terminology (such as use of "burning" when
I should say "pyrolysis") leaves much to be desired. But Ron responded so
well that now Crispin has been able to respond with some clear statements
that raise questions.

2. When properly functioning (which was not the case with my stoves on
Crispin's patio), the Juntos stove does NOT give noticeable "smoke" (that I
think of as "visible particles"), but there are certainly some issues of
unseen gasses, as with all stoves. When the Juntos gasifier unit has
sufficient chimney of a couple of inches, the gasification goes to the end
without smoke, with the result being only glowing charcoal. Problems arise
when some of the fuel has fallen through the grate and therefore continues
to give gasses (smoke) when the charcoal is removed.

3. A stove that is lighted, functioning, and hot is a different beast from
a cool-start stove. Therefore, adding in fuel on top of a hot charcoal bed
WITH EXTREME CONTROL OF THE PRIMARY AIR entering under the charcoal COULD
(in my humble opinion) have pyrolysis gasification down low where the
charcoal is in contact with the new fuel and then also have the secondary
combustion of the gases a few inches above the top of the fuel load. But
issues of fuel types (including different moisture content of the same
fuel) could become more important than when those fuels were in the
top-lighted gasification configuration.(?)

Please keep the comments coming, and feel free to separate out the diverse
topics into separate threads of messages.

I am learning, and I hope others are also.

Paul

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From CAVM at aol.com Sat Apr 13 18:26:54 2002
From: CAVM at aol.com (CAVM@aol.com)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of gasification
Message-ID: <44.1e48d702.29ea50c9@aol.com>

Andrew, et al, you said,

... "however even commercial sized gasification units seem to discardchar
with the ash, it's inevitable really as chemical reactions tend
to equilibriums, if you supply just the 1kg of air needed to gasify
1kg of dry biomass then some will react all the way to produce H2O and
CO2, hence some char must be left. In a simple stove we can add excess
air above the 6kg needed for stoichiomentric conditions, this allows
unreacted O2 to leave the system rather than unreacted C."

So, anybody have any idea how much water we get as a byproduct for the
gasification of X amount of biomass of any type? Can it be captured?

Neal Van Milligen

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From ronallarson at qwest.net Sat Apr 13 20:20:58 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <002501c1e2b3$8fc59ac0$52e80fc4@home>
Message-ID: <019e01c1e374$2818a5e0$71e06641@computer>

Dear Crispin (cc stoves):

Today you said: <snip header>

> First:
> I wrote to Paul: "I am still waiting to hear ANY reasonable explanation
for
> not smoking off the wood in any pattern or position."
>
> This followed the discussions and experiments we had together a few weeks
> ago in Swaziland. Paul brought a few small gasifying stoves with him and
we
> lit a couple on my (cement) veranda.
>
> We tried one with chopped wood and it flamed very nicely. Clean, hardly
any
> visible emissions after the flame was established (don't think it doesn't
> smoke at all - it smokes at the beginning and a lot at the end).
>
(RWL1): To those who haven't tried this, the early smoking is about
what you see with any stove start-up. That at the end (or if there is an
inadvertent flameout due to a breeze) is awful. This is one of the major
problems with charcoal-making stoves - and one that needs a lot more work.
I try to quickly snuff or transport the hot charcoal to another location.
Others open the primary supply a lot and try to consume it in situ. (In my
last paragraph, I discuss this in situ point further.)

> When it burned down to charcoal, at which time it smoked profusely, I
added
> more chopped wood on top. It went out. Next time I added it just before
> the pyrolysis stopped and it re-established itself as a gasifying stove.
> This gassing and flaming continued as the new fuel (added on top of the
hot
> charcoal which remained at the bottom) pyrolysed to produce gas in the
> regular way, though it no longer had a top-down flame front. It was hot
> here and there.
>
(RWL2): a. "the regular way, though it no longer had a top-down flame
front." perhaps needs a bit more discussion. I presume that the newly added
pieces were somewhat near the secondary air supply - but I am guessing that
they were profusely outgassing due to the relatively high temperature gases
coming from below and not due to surface reactions (as were occuring at the
pyrolysis front below). There is also considerable heat input from the
radiation coming from above. To those who haven't seen this phenomenon - it
is very satisfying to see the rapid increase in flaming, with the top-added
fuel. I agree that you can't do it late in the process. I should also note
that I try to use longish twigs and small branches - which do not shrink
greatly longitudinally as they are turned to charcoal. There is much
greater shrinkage radially. Thus the top of the charcoal in my tests is
probably closer to the secondary air supply in my tests than those Crispin
is describing - and certainly in those of Tom.
b. re "It was hot here and there." - I presume you are saying that you
did not have the relative uniformity I have been claiming. Can you describe
this more fully? I often get hot spots near the primary air holes - was
that the case? Was it a problem?

> It was top-lit to begin with and bottom lit for refueling and middle lit
> during the second burn.

(RWL3): Sorry - not understanding the "middle lit during the second
burn". Can you describe your control of primary air - and where the flame
appeared to originate? Could this be ignition of pyrolysis gases produced
as I described above? That is - where was the necessary oxygen coming
from - the primary air ports or the secondary air "ring".

>
> I have been reading for 6 months on this list that this cannot be done and
> doesn't work and gives off uncontrollable amounts of gas. Paul told me
just
> before we did it that it wouldn't work, but Paul also taught me to try and
> see just for the heck of it, so I did.
>
(RWL4): If you go back in the archives (not that I recommend the
search) - I believe you will find other discussions of adding extra fuel. I
don't remember any denial of that possibility. But if your aim is to
produce charcoal (my aim), this is not particularly helpful. I would say
that what you did was rather like the upper fuel container in Paul's Juntos
stove - and one that can be very helpful in long burns, requiring refueling

> Refuelling works very nicely with regular wood. Perhaps it won't work
with
> pelletized wood.

(RWL5): I think it should - if you also increase air flow openings to
compensate for the added air flow resistance .
>
> Second:
> I feel there are some apples mixed in with the oranges. Ron wrote,
> "Charcoal is indeed made in the way Crispin describes. Unfortunately, it
is
> one of the most abominable practices on the face of the earth..."
>
> Well...yes it is when done to produce charcoal from wood in a forest, but
we
> are not doing that. The significant difference is that in the stove we
are
> not burning wet wood. This is an important consideration. A number of
the
> complaints about the process and the chemical analyses discussed for
> emissions and flamability of the gasses are made with reference to wet
wood
> in a forest, not dry wood in a stove. In other words some of the
arguments
> presented against bottom lighting a gassifying stove are based on an
> analysis of wet wood charcoal production.

(RWL6): a. I contend that the copious smoke in traditional rural
charcoaling could often be flared - and that flaring should be mandated.
The first step is to use drier wood. Apparently this is usually not done,
for fear that the downed, piled (generally wet) wood will be stolen. But
the use of wet wood not only prevents flaring, but also requires
considerable combustion of produced charcoal to dry the wood out.
b. Several on the list have been exploring the use of recirculated
steam for drying the incoming wet wood - quite a fascinating way to use the
"waste" heat - and not having a problem with the flaring. I haven't seen a
cheap easy way to do this with a stove.
c. I lived for a few months in Sweden (partly working on charcoaling
stoves) in 1995. It seemed like every home had a huge pile of wood near
it - and I believe it was "seasoned" for two years. You obviously favor
using dry wood and I concur. My argument against bottom lighting is not
based on moisture content alone. I still don't believe one can get
adequately clean combustion or controllability with bottom lighting.

>
> Tom recommends that the fuel be "...0-25% moisture content...". That is
not
> the condition in a forest-based charcoal production so to be useful we
> should limit the discussion of charcoal making stoves to forseeable
> conditions in a stove.
>
(RWL7): One reason for my bringing in the "forest-based" approach was
to say that it seems to be based on bottom lighting. I have tried to read
everything I could on forest-based approaches - and never have found a
description of "top-lighting". Some of the Swedish charcoaling literature
seems to imply that something equivalent was happening (but in 3-D). The
standard (smoky, non flared) approaches to charcoaling are bottom lit -
presumably because this is so common for every other form of biomass
conversion.

> On Apr 03 Tom wrote, "...gasifiers burn at a VERY constant rate until the
> volatiles are gone...".
>
> This is a very important point and one that can be considered essential in
> certain cooking applications. However constancy is not a good thing if
you
> want to vary the output of heat because once it is going I have found
> gassifying stoves to be quite difficult to control vis-a-vis the heat
> output. Getting high heat is difficult. It is very important to keep in
> mind that there is zero hope of us in the field getting the fuel Tom is
> using to achieve this constant heat output. The experiment, if I may call
> it that, is burning unobtanium.
>
(RWL8): a. There has been considerable discussion on this list of
different ways to control the primary air - which seems to have a linear
relationship to output. We have talked about various plugs (my favorite),
and rotating and sliding flaps and vanes. A big topic of discussion has
been "turn-down" ratio - with "3" being a common value (Max power maybe 9
kW, min power maybe 3 - depending mostly on the diameter). But it appears
that you were doing your tests without being able to vary the primary air
supply - and that is a (probably "THE") key element of the top-lighting
approach. So when we brag about "constancy" - that is a statement of
constancy after setting the desired power level (within the turn-down ratio
limits). It is not meant at all to imply that only a single power level is
possible. I presume most of us also open the primary air port to the
maiximum during startup. The fuel I always try to use is picked up off the
ground - definitely not "unobtainium." And to repeat, the power output
variation is quite independent of the fuel - it is directly related to stove
size and primary air supply.
b. I am very confused about why your tests seemed to have no control
over primary air supply. If you can supply the data on weight of fuel and
duration of the pyrolysis phase, I can estimate your power output and I
assert that with some modifications you should be able to vary the power
(and/or time) over about a 3:1 ratio. Below are some comments on Tom's data
that are along this line - ie 10 grams per minute being about 3 kW.

> The heat requirement in our area is for a lot of heat at the beginning
> followed by a significant turndown and a long simmer. This can be
achieved
> by lighting up a relatively large amount of gasses followed by a
relatively
> small amount after 20-30 minutes. This is approximately what happens if
you
> bottom light a charcoaling stove, according to Tom recent message with the
> Camp Stove data attached. Tom's statement that the gas cannot be burned
> effectively because of a lack of air being available immediately after
> adding fuel to an operating stove is conditioned upon a certain stove
> design, not something inherent in the making of gasses and charcoal.
> Perhaps this observation could be rephrased as, "If you add fuel to an
> operating IDD stove, there will initially be a large amount of gas
> produced." The ability of the stove to burn it effectively is a different
> matter and does not limit the type of stove you might construct.

(RWL9): I think you have read Tom's message of Thursday correctly - but one
should not assume that his stove (or any) should be used that way to get a
lot of early power. I think Tom was also saying that there were way too
many emissions (unburned gases) because of the bottom-lighting. I am not
sure that Tom would agree that one can design a bottom lighting stove
(pyrolyzing or not) that will give the desired range of power output (It
sounds like you want a turndown ratio of perhaps 5 or more). The standard
US gas stove doesn't do that well with one burner I believe (I think Tom has
reported that electric ranges (like mine) have about 3 - anyone able to
report a number for a modern gas range?

In his Thursday message, Tom said: "(10 g/hr = 3 kW for our stoves on
high)". Tom obviously meant 10 g per minute or 600 g per hour. However,
since I saw this small typo, I looked more closely at Tom's data and can say
that a more accurate pair of values would be 7.5 g/minute and 450 g per
hour. Three other comments seem appropriate on Tom's nice data and graph
(which some may not have seen - as you have to change pages on his Excel
spread sheet).
a. First, the linearity of the power output (or g/min) data is well
apparent over a 37 minute period. I doubt anyone doing a non-pyrolyzing
stove can show anything similar over even a one minute period. This was all
done on a single (high) setting - but I am sure Tom could show us a similar
plot with a high and a low setting - both with similar linearity
b. The ratio of water evaporated to fuel converted (both in g/min - the
slopes) is very nearly 3 in Tom's test. I'd like to hear from others as to
whether they have a better Figure of Merit number to report. I do not know
whether Tom had a "convection/radiation shield" around the pot - but his
ratio is a very good one.
c. I want to argue that Tom's efficiency computation (in cell B20)
given by Tom is overly simplified - as it gives no credit to the charcoal
being produced (As indicated above, I would use a weight ratio slightly
less than the 220/70 given by Tom - but that is not my point). This
equation would be correct if no charcoal was being produced (assuming Tom's
energy density value of 18.9 MJ per kg is correct) - but we who like
charcoal have to be picky on this point. In some of the stove literature I
have seen, the residual charcoal weight (15.5%) is subtracted from the wood
weight for the efficiency computation. This would raise the efficiency
value by 1/(1-.155) or about 38%*1.18=45%. If one gives credit to the
different energy contents of wood (18.9 MJ/kg) and charcoal (28? MJ/kg), one
should subtract not 15.5% but something more like 15.5*(28/18.9) = 23%.
Thus Tom's energy efficiency might be revised from 45% to
38%/(1-(.145/.845)*(28/18.9)) = 38/(.75) = 50.7%.
[We have to come back to this later - but I have a further quibble with
even this adjustment, I don't like the subtraction of terms in a
denominator. I would rather be messing with two numerator co-product terms
that are additive. If we were only interested in making charcoal, Tom's data
would give a conversion efficiency of 15.5%*28/18.9 = 23%. I would add this
to Tom's computation of 38% (during this phase only, not overall) and get
61% efficiency. Who disagrees and why? ]

>
> I have not observed the gassing phenomenon Tom describes using chopped
wood.
> One reason for that may be the smaller surface-to-volume ratio of the wood
> compared with the pellets.
>

(RWL10): Not sure how to respond - I guess you are saying you never saw
too much gas when you added extra fuel. And I would say the same. Tom
would probably also agree if he added less fuel - or he might say that you
can always add too much.

> Third:
> It is important to me to know if Ron's statement, "The problem is that the
> valuable combustible gases that are released are so diluted by carbon
> dioxide and water content that it is not combustible when emitted from
> traditional (or even improved) charcoal kilns." holds true for stove-based
> gas production. Am I right in observing that this is only a problem when
> working with wet wood in a forest? By forest I am thinking of a
> batch-process stacked log charcoaling operation.
>
(RWL11) I say that the issue relates greatly to where the secondary air
is coming from. In stoves like the Rocket stove, both the primary air and
secondary air are introduced from below. If you are producing lots of
uncombusted gases along with the CO2 and steam, and the secondary air is not
mixed in soon enough, then you will have excessive emissions. My reading of
the limited lab measurements we have is that 5% CO in the exit stream is
common for usual (bottom lit) stoves. I don't think that the best are that
bad, but they are nowhere near zero either.

> I have a chemistry question. If I were to charcoal a small amount of dry
> wood in a stove, and produced the aforementioned high CO2 gasses, is that
> not OK in that all I want is the heat, after all I am trying to cook here.
> I am not particularly after CO.
>
(RWL12): As I am getting to this point - I have been out for the evening
and now pooped. Since I also find that Andrew Heggie has answered a lot of
these questions, and I have written too much, and am busy in the AM, I am
going to stop here. I will try to pick up again at this point - as Crispin
has asked some excellent questions. On this one question above, I would
say that it is very difficult - if not impossible - to produce charcoal and
CO2 at the same time. If you want charcoal, you are well off getting the CO
(and CH4 and H2) - which are better off burned as close to the pot as
possible. If one starts combusting the charcoal at the end of the
pyrolysis phase, that production of heat and CO2 is way at the bottom of the
pile of charcoal (we don't see a flame above the charcoal typically), and
the plots of energy output (as seen by achievable temperature in the pot)
are very discouraging. Although the charcoal is disappearing, essentially
no useful work is being accomplished - just because the charcoal and air
supply are in the wrong places. I feel it much better to salvage the
charcoal as soon as the pyrolysis front reaches the bottom - and then sell
it and/or use it in a combuster designed for that job. There is not a great
deal of money to be made this way, but for a woman making zero income, even
a small income can be quite liberating.

More promised. Ron

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From kchisholm at ca.inter.net Sat Apr 13 21:05:40 2002
From: kchisholm at ca.inter.net (Kevin Chisholm)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of gasification
In-Reply-To: <44.1e48d702.29ea50c9@aol.com>
Message-ID: <00ca01c1e37a$1e36aee0$3419059a@kevin>

Dear Neal
...del...
>
> So, anybody have any idea how much water we get as a byproduct for the
> gasification of X amount of biomass of any type?

I don't think there is any single answer to your question. The first
variable is the moisture in the fuel. The next variable is the specific
process employed.

A gasifying process with a "low temperature reaction", low moisture, and low
excess air, can be expected to produce an off-gas with most hydrogen tied
up in tars. A high temperature process, with optimal water and air can lead
to a gas which is low in tars, and high in CO, H20 and N2.

> Can it be captured?
>
The moisture can be dropped out with condensers. The degree of drop-out
depends on the dewwpoint of the exit gas.

Kevin Chisholm

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From adkarve at pn2.vsnl.net.in Sat Apr 13 21:50:17 2002
From: adkarve at pn2.vsnl.net.in (A.D. Karve)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
Message-ID: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>

Paul asked what difference it made if the gas burnt in the upper part of the
stove and the charcoal on the grate. According to him, heat was heat, and
as long as all the fuel was burnt, and all the heat released, it should not
make any difference, whether the heat came from the gas or from the
charcoal. I feel that the location of combustion has an effect on
transfering the heat to the pot. The charcoal burning on the grate is at
least six inches from the pot and therefore it may not trasfer all its heat
to the pot, whereas the gas burning just below the pot may trasnfer
relatively more heat to the pot. That is why it makes sense if the volatile
part of wood and the charcoal are burnt in two separate stoves, each
designed to burn a specific fuel.
A.D.Karve
-----Original Message-----
From: Paul S. Anderson <psanders@ilstu.edu>
To: Crispin <crispin@newdawn.sz>; Stoves <stoves@crest.org>
Cc: Bob and Karla Weldon <bobkarlaweldon@cs.com>; Ed Francis
<cfranc@ilstu.edu>; Tsamba--Alberto Julio <ajtsamba@zebra.uem.mz>; Lily
Coyle <astrozen2000@hotmail.com>
Date: Sunday, April 14, 2002 3:21 AM
Subject: Re: Gasifier fundamental question

>Stovers,
>
>Crispin wrote, and I emphasize:::::::
>
>>Many thanks for all the energy contributors spend adding fuel to this
fire!
>
>And that includes Crispin messages, too.
>
>Short Notes from Paul:
>
>1. Ron correctly notes that MY terminology (such as use of "burning" when
>I should say "pyrolysis") leaves much to be desired. But Ron responded so
>well that now Crispin has been able to respond with some clear statements
>that raise questions.
>
>2. When properly functioning (which was not the case with my stoves on
>Crispin's patio), the Juntos stove does NOT give noticeable "smoke" (that I
>think of as "visible particles"), but there are certainly some issues of
>unseen gasses, as with all stoves. When the Juntos gasifier unit has
>sufficient chimney of a couple of inches, the gasification goes to the end
>without smoke, with the result being only glowing charcoal. Problems arise
>when some of the fuel has fallen through the grate and therefore continues
>to give gasses (smoke) when the charcoal is removed.
>
>3. A stove that is lighted, functioning, and hot is a different beast from
>a cool-start stove. Therefore, adding in fuel on top of a hot charcoal bed
>WITH EXTREME CONTROL OF THE PRIMARY AIR entering under the charcoal COULD
>(in my humble opinion) have pyrolysis gasification down low where the
>charcoal is in contact with the new fuel and then also have the secondary
>combustion of the gases a few inches above the top of the fuel load. But
>issues of fuel types (including different moisture content of the same
>fuel) could become more important than when those fuels were in the
>top-lighted gasification configuration.(?)
>
>Please keep the comments coming, and feel free to separate out the diverse
>topics into separate threads of messages.
>
>I am learning, and I hope others are also.
>
>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
>
>
>-
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>
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From andrew.heggie at dtn.ntl.com Sun Apr 14 03:53:29 2002
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of gasification
In-Reply-To: <44.1e48d702.29ea50c9@aol.com>
Message-ID: <56tibusmnljj3f4plba5u3iife7jdah38s@4ax.com>

On Sat, 13 Apr 2002 23:26:01 EDT, CAVM@aol.com wrote:

>
>So, anybody have any idea how much water we get as a byproduct for the
>gasification of X amount of biomass of any type?

There should be no water in gasification of any solid fuel, the
products should ideally all leave the system as CO N2 and H2 in an air
blown gasifier. In practice tars and products like alkali metal
compounds are formed.

The question should go over to the gasification list.

I think you probably meant was can we calculate the amount of water in
the flue of a biomass combustion device, to which Kevin has given an
answer.

More fully we can calculate the water resulting from combustion of dry
biomass. Tom Reed has modeled woody biomass as C10H14O6 plus ash, as a
rule of thumb. So for each mole of this idealised "wood" we can
combust it to yield 7H2O, about 54% of the dry ash free weight of the
biomass.

To this must be added the water from the original moisture content of
the wood and the trivial amount in the humidity of the combustion air.

>Can it be captured?

Some quite easily with a flue gas condenser depending on the
temperature and humidity of the ambient air, the remainder only with
great difficulty. All at considerable additional capital cost.

AJH

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From kchisholm at ca.inter.net Sun Apr 14 06:08:24 2002
From: kchisholm at ca.inter.net (Kevin Chisholm)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>
Message-ID: <001d01c1e3c5$f93d6f60$3e19059a@kevin>

Dear Dr. Karve

I think Paul is asking the wrong question, when he asks if it makes any
difference where the fuel is being burned.

The answer to that question is, to me, in my blatant humble opinion, is very
obvious: It must be burned where the stove design requires it to be burned.

I also feel that a stove design which has a yellow flame contacting a
surface from which heat is being removed is a poor design, in that the
combustion in process will be partially quenched, leading to blackening of
the pots, loss of heat transfer capability, loss of heating value, and the
presence of the products of partial combustion in the off-gas products.

Kindest regards,

Kevin Chisholm

----- Original Message -----
From: "A.D. Karve" <adkarve@pn2.vsnl.net.in>
To: <stoves@crest.org>
Cc: "Paul S. Anderson" <psanders@ilstu.edu>
Sent: Saturday, April 13, 2002 10:03 PM
Subject: Re: Gasifier fundamental question

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From CAVM at aol.com Sun Apr 14 06:15:39 2002
From: CAVM at aol.com (CAVM@aol.com)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of gasification
Message-ID: <10d.10935d78.29eaf6e7@aol.com>

Let me explain my reasoning for thinking that water is a byproduct. We
developed a new heating system for poultry houses in part to combat the
humidity put into the air by the old open flame propane brood heaters. Now
the poultry houses in KY use our hot water heating system in many of the
houses.

If water vapor comes off of the combustion of propane and natural gas, I
reasoned that it would like wise be a byproduct of the combustion of gas from
a gasifier.

If I had an unlimited inexpensive fuel, a gasifier and a use for the heat
produced by the combustion of the gas, water could be a cheap byproduct of
the process. Let's say that I had a large coal mine in an arid area. I want
to gasify the coal, burn the gas and collect the water byproduct. Of course,
the burning of the gas would be in a value added process, not wasted.

If this is correct, even to a small degree, couldn't a gasifier stove in an
arid part of Africa, Afghanistan or anywhere, produce a small amount of
collectable water as it did its work?

Neal Van Milligen
CAVM@AOL.com

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From andrew.heggie at dtn.ntl.com Sun Apr 14 07:17:20 2002
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of gasification
In-Reply-To: <10d.10935d78.29eaf6e7@aol.com>
Message-ID: <2eajbu8deirv72dv7nrelf3fmpo0uqh2p2@4ax.com>

On Sun, 14 Apr 2002 11:14:47 EDT, CAVM@aol.com wrote:

>
>If water vapor comes off of the combustion of propane and natural gas, I
>reasoned that it would like wise be a byproduct of the combustion of gas from
>a gasifier.

Reasonable assumption for a gasifier working on woody biomass.
>
>If I had an unlimited inexpensive fuel, a gasifier and a use for the heat
>produced by the combustion of the gas, water could be a cheap byproduct of
>the process. Let's say that I had a large coal mine in an arid area. I want
>to gasify the coal, burn the gas and collect the water byproduct. Of course,
>the burning of the gas would be in a value added process, not wasted.

Trouble is that coal is basically carbon with a few hydrocarbons
associated with it i.e. very little hydrogen in the fuel, water is
only formed by the oxidation of this hydrogen. You can make hydrogen
during gasification of coal but only by adding water (which you don't
have available in this instance.
>
>If this is correct, even to a small degree, couldn't a gasifier stove in an
>arid part of Africa, Afghanistan or anywhere, produce a small amount of
>collectable water as it did its work?

Only if run on biomass and then only at vastly increased capital cost.

AJH

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From kchisholm at ca.inter.net Sun Apr 14 07:36:25 2002
From: kchisholm at ca.inter.net (Kevin Chisholm)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of gasification
In-Reply-To: <10d.10935d78.29eaf6e7@aol.com>
Message-ID: <006901c1e3d2$4381c560$3e19059a@kevin>

Dear Neal

What you are getting at basically is a "condensing stove."

This can certainly be done. Simply cool the flue gasses below their
dewpoint, and collect the dew.

However, there would probably be a lot of problems with condenser
construction and operation. It should be stainless steel, at least in the
"front end", and possibly plastics could be used in the "tail end" to get
extra surface for heat exchange. There may be operating problems with tars
and particulates building up on the condenser surfaces.

The "water quality" would be something else again. With a sulphurous fuel,
the condensate would be acidic. With biomass, it could be acid to neutral to
strongly alkaline, depending on the presence of ash and products of partial
or complete combustion.

As a "best possible scenario", contact somebody who sells a propane or
natural gas condensing furnace, and ask them about he quality of the
condensate. Biomass condensate would be downhill from there.

Kindest regards,
Kevin Chisholm

----- Original Message -----
From: <CAVM@aol.com>
To: <stoves@crest.org>
Sent: Sunday, April 14, 2002 12:14 PM
Subject: Water as a byproduct of gasification

> Let me explain my reasoning for thinking that water is a byproduct. We
> developed a new heating system for poultry houses in part to combat the
> humidity put into the air by the old open flame propane brood heaters.
Now
> the poultry houses in KY use our hot water heating system in many of the
> houses.
>
> If water vapor comes off of the combustion of propane and natural gas, I
> reasoned that it would like wise be a byproduct of the combustion of gas
from
> a gasifier.
>
> If I had an unlimited inexpensive fuel, a gasifier and a use for the heat
> produced by the combustion of the gas, water could be a cheap byproduct of
> the process. Let's say that I had a large coal mine in an arid area. I
want
> to gasify the coal, burn the gas and collect the water byproduct. Of
course,
> the burning of the gas would be in a value added process, not wasted.
>
> If this is correct, even to a small degree, couldn't a gasifier stove in
an
> arid part of Africa, Afghanistan or anywhere, produce a small amount of
> collectable water as it did its work?
>
> Neal Van Milligen
> CAVM@AOL.com
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
> Stoves List Moderators:
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> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>

Stoves List Moderators:
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From dstill at epud.net Sun Apr 14 09:09:28 2002
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:37:46 2004
Subject: ETHOS website
Message-ID: <006101c1e3ce$8e677ec0$9f1d66ce@default>

Dear Friends,

http://quickplace.udayton.edu/ETHOS Thanks to the amazing Chris Schmidt,
who directs ETHOS at University of Dayton, the ETHOS website is up and
flying. You can see and download the papers from the Seattle conference,
etc. Many folks are working on ETHOS projects and future papers will be
available at this site. There's even a picture of Larry, Dean, Tom, Ron,
Mark, Tami, etc. although without captions you'll only know me because I'm
probably the biggest white haired guy in the room, smiling.

Best,

Dean

Stoves List Moderators:
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From tombreed at attbi.com Sun Apr 14 13:33:18 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>
Message-ID: <001401c1e403$c7407690$4bc0fd0c@TOMBREED>

Dear All:

I agree with Karve that it makes a LOT of difference where the charcoal is
burned. In our WoodGas CampStove the volatiles burn at the top of the
gasifier with secondary air, producing a flame like propane and high heat.

When the volatiles are completely burned, the combustion/gasification of the
charcoal is near the bottom of the gasifier, 10 cm from the pot and so much
of the radiation heat is disipated.

However, if we INCREASE the air to the charcoal, it is gasified to CO in
sufficient quantity to produce a beautiful CO flame at the secondary air
holes.

The air fuel ratio for volatiles in a dry fuel is about 1. For charcoal it
is 6!

TOM REED BEF GASWORKS
----- Original Message -----
From: "A.D. Karve" <adkarve@pn2.vsnl.net.in>
To: <stoves@crest.org>
Cc: "Paul S. Anderson" <psanders@ilstu.edu>
Sent: Saturday, April 13, 2002 7:03 PM
Subject: Re: Gasifier fundamental question

> Paul asked what difference it made if the gas burnt in the upper part of
the
> stove and the charcoal on the grate. According to him, heat was heat, and
> as long as all the fuel was burnt, and all the heat released, it should
not
> make any difference, whether the heat came from the gas or from the
> charcoal. I feel that the location of combustion has an effect on
> transfering the heat to the pot. The charcoal burning on the grate is at
> least six inches from the pot and therefore it may not trasfer all its
heat
> to the pot, whereas the gas burning just below the pot may trasnfer
> relatively more heat to the pot. That is why it makes sense if the
volatile
> part of wood and the charcoal are burnt in two separate stoves, each
> designed to burn a specific fuel.
> A.D.Karve
> -----Original Message-----
> From: Paul S. Anderson <psanders@ilstu.edu>
> To: Crispin <crispin@newdawn.sz>; Stoves <stoves@crest.org>
> Cc: Bob and Karla Weldon <bobkarlaweldon@cs.com>; Ed Francis
> <cfranc@ilstu.edu>; Tsamba--Alberto Julio <ajtsamba@zebra.uem.mz>; Lily
> Coyle <astrozen2000@hotmail.com>
> Date: Sunday, April 14, 2002 3:21 AM
> Subject: Re: Gasifier fundamental question
>
>
> >Stovers,
> >
> >Crispin wrote, and I emphasize:::::::
> >
> >>Many thanks for all the energy contributors spend adding fuel to this
> fire!
> >
> >And that includes Crispin messages, too.
> >
> >Short Notes from Paul:
> >
> >1. Ron correctly notes that MY terminology (such as use of "burning"
when
> >I should say "pyrolysis") leaves much to be desired. But Ron responded
so
> >well that now Crispin has been able to respond with some clear statements
> >that raise questions.
> >
> >2. When properly functioning (which was not the case with my stoves on
> >Crispin's patio), the Juntos stove does NOT give noticeable "smoke" (that
I
> >think of as "visible particles"), but there are certainly some issues of
> >unseen gasses, as with all stoves. When the Juntos gasifier unit has
> >sufficient chimney of a couple of inches, the gasification goes to the
end
> >without smoke, with the result being only glowing charcoal. Problems
arise
> >when some of the fuel has fallen through the grate and therefore
continues
> >to give gasses (smoke) when the charcoal is removed.
> >
> >3. A stove that is lighted, functioning, and hot is a different beast
from
> >a cool-start stove. Therefore, adding in fuel on top of a hot charcoal
bed
> >WITH EXTREME CONTROL OF THE PRIMARY AIR entering under the charcoal
COULD
> >(in my humble opinion) have pyrolysis gasification down low where the
> >charcoal is in contact with the new fuel and then also have the secondary
> >combustion of the gases a few inches above the top of the fuel load. But
> >issues of fuel types (including different moisture content of the same
> >fuel) could become more important than when those fuels were in the
> >top-lighted gasification configuration.(?)
> >
> >Please keep the comments coming, and feel free to separate out the
diverse
> >topics into separate threads of messages.
> >
> >I am learning, and I hope others are also.
> >
> >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
> >
> >
> >-
> >Stoves List Archives and Website:
> >http://www.crest.org/discussion/stoves/200202/
> >http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> >http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
> >
> >Stoves List Moderators:
> >Ron Larson, ronallarson@qwest.net
> >Alex English, english@adan.kingston.net
> >Elsen L. Karstad, elk@wananchi.com www.chardust.com
> >
> >List-Post: <mailto:stoves@crest.org>
> >List-Help: <mailto:stoves-help@crest.org>
> >List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> >List-Subscribe: <mailto:stoves-subscribe@crest.org>
> >
> >Sponsor the Stoves List: http://www.crest.org/discuss3.html
> >-
> >Other Biomass Stoves Events and Information:
> >http://www.bioenergy2002.org
> >http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> >http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> >http://www.crest.org/articles/static/1/1011975672_7.html Carbon
> >
> >For information about CHAMBERS STOVES
> >http://www.ikweb.com/enuff/public_html/Chamber.htm
> >
> >
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Alex English, english@adan.kingston.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
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>
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>

From tombreed at attbi.com Sun Apr 14 13:41:30 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of combustion...
In-Reply-To: <10d.10935d78.29eaf6e7@aol.com>
Message-ID: <002001c1e404$ecd775b0$4bc0fd0c@TOMBREED>

Dear All:

I have long been puzzled by the emphasis on carbon dioxide as a greenhouse
gas. Water it the primary greenhouse gas and I found this statement at
http://www.greenhouse.gov.au/inventory/inventory/inv_content.html
"Water vapour is the major greenhouse gas in the Earth's atmosphere. Human
activity has little effect on water vapour concentrations compared with
natural systems like ocean evaporation. As the NGGI is primarily concerned
with greenhouse gas emissions resulting from human activity, water vapour is
not included."

The concentration of water is many times greater than CO2, and most
combustion processes release as much water as CO2. Switching to hydrogen
solves nothing....

Comments?

Tom Reed

----- Original Message -----
From: "AJH" <andrew.heggie@dtn.ntl.com>
To: <stoves@crest.org>
Sent: Sunday, April 14, 2002 10:15 AM
Subject: Re: Water as a byproduct of gasification

On Sun, 14 Apr 2002 11:14:47 EDT, CAVM@aol.com wrote:

>
>If water vapor comes off of the combustion of propane and natural gas, I
>reasoned that it would like wise be a byproduct of the combustion of gas
from
>a gasifier.

Reasonable assumption for a gasifier working on woody biomass.
>
>If I had an unlimited inexpensive fuel, a gasifier and a use for the heat
>produced by the combustion of the gas, water could be a cheap byproduct of
>the process. Let's say that I had a large coal mine in an arid area. I
want
>to gasify the coal, burn the gas and collect the water byproduct. Of
course,
>the burning of the gas would be in a value added process, not wasted.

Only if run on biomass and then only at vastly increased capital cost.

AJH

Stoves List Moderators:
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From tombreed at attbi.com Sun Apr 14 13:45:00 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:46 2004
Subject: Gasifier fundamental question
In-Reply-To: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>
Message-ID: <002801c1e405$6a434f10$4bc0fd0c@TOMBREED>

Dear All;

I agree with Kevin Chisholm's remarks about "yellow flame quenching". The
fraction of the visible yellow flame that is intercepted by the pot is the
fraction that is not burned well and by which heat transfer is reduced
(approximately).

It also blackens the pot. So our woodgas stoves are designed to burn with
appropriate air and no yellow flames.

TOM REED BEF STOVEWORKS
----- Original Message -----
From: "Kevin Chisholm" <kchisholm@ca.inter.net>
To: "A.D. Karve" <adkarve@pn2.vsnl.net.in>; <stoves@crest.org>
Sent: Sunday, April 14, 2002 9:04 AM
Subject: Re: Gasifier fundamental question

> Dear Dr. Karve
>
> I think Paul is asking the wrong question, when he asks if it makes any
> difference where the fuel is being burned.
>
> The answer to that question is, to me, in my blatant humble opinion, is
very
> obvious: It must be burned where the stove design requires it to be
burned.
>
> I also feel that a stove design which has a yellow flame contacting a
> surface from which heat is being removed is a poor design, in that the
> combustion in process will be partially quenched, leading to blackening of
> the pots, loss of heat transfer capability, loss of heating value, and
the
> presence of the products of partial combustion in the off-gas products.
>
> Kindest regards,
>
> Kevin Chisholm
>
> ----- Original Message -----
> From: "A.D. Karve" <adkarve@pn2.vsnl.net.in>
> To: <stoves@crest.org>
> Cc: "Paul S. Anderson" <psanders@ilstu.edu>
> Sent: Saturday, April 13, 2002 10:03 PM
> Subject: Re: Gasifier fundamental question
>
>
> > Paul asked what difference it made if the gas burnt in the upper part of
> the
> > stove and the charcoal on the grate. According to him, heat was heat,
and
> > as long as all the fuel was burnt, and all the heat released, it should
> not
> > make any difference, whether the heat came from the gas or from the
> > charcoal. ..
> ...del...
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200202/
> http://crest.org/discussiongroups/resources/stoves/ (Under construction)
> http://www.ikweb.com/enuff/public_html/Stoves.html (Original)
>
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Alex English, english@adan.kingston.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
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>
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> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
>
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>

From kchisholm at ca.inter.net Sun Apr 14 15:30:50 2002
From: kchisholm at ca.inter.net (Kevin Chisholm)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of combustion...
In-Reply-To: <10d.10935d78.29eaf6e7@aol.com>
Message-ID: <00d001c1e414$89440620$3e19059a@kevin>

Dear Tom

The problem with CO2 is that it "raises the base level" of Earth
Atmosphere's heat retaining capability.

With a higher average temperature, there is more energy available within the
biosphere, for "re-boiling" water vapor. One can thus expect more storms,
from this line of logic.

The offsetting factor could be that with more water vapor in the air, there
will be more clouds, and more reflection of sunlight back into Space, and a
tendency for Global Cooling to offset CO2's tendency for global warming.
However, if cloud cover does not increase significantly more than what it is
now, this "tempering mechanism" will not cut in.

Kindest regards,

Kevin Chisholm

From d.rl at virgin.net Mon Apr 15 01:02:08 2002
From: d.rl at virgin.net (David Reynolds-Lacey)
Date: Tue Aug 31 21:37:46 2004
Subject: Another Lurker pop's up!
Message-ID: <3CBAA511.A1738498@virgin.net>

Hello Stovers,

I have been lurking on the list for several months
now so it's about time to say hello to all of you.
I found the list during a search for "charcoal
retorts".

First, a little about myself. I am 58 and live in
Worcestershire, England, I retired 10 years. ago
from from my telecommunications business and have
dedicated my time since then to restoration and
conservation work. Five years ago I purchased a
much neglected and overgrown 150 acre semi natural
ancient woodland site near to my home and set
about restoring it using traditional methods. The
site has a long history in charcoal making
(especially for gunpowder production), small scale
coal mining and brick making. After spending 3
years restoring some of the infrastructure I began
coppicing work, with just 5 acres done to date. So
far I have only been able to produce firewood and
charcoal but when the coppice is in proper
rotation I intend to engage in a variety of
traditional woodland crafts. I am now able to
employ 2 full time workers and have one student
trainee from a local agricultural college, I will
provide more training places as we progress. It
is my aim to make my operation completely self
sustaining, both financially and energy-wise and
my current energy scheme is to produce heat and
electrical/mechanical power entirely from forest
debris using all equipment that I have built
myself. I care passionately about the environment
and having spent time in some developing
countries, especially South Africa, I would like
to think my work could also be of benefit in these
areas. My primary skills are in business
management, sales and marketing but I am a general
"all rounder" with a strong bias towards
mechanical engineering.

Whilst I haven't posted to the list before, I
have contacted 3 list members off list. The first
was Dan Dimiduk, who as well as giving me a great
deal of help and information also put me in
contact with Ken Boak, now Ken and I are looking
at projects involving flash steam, Stirling
engines and a "stoves" related project, which is
current. I also contacted Andrew Heggie and I am
the "Lurker" referred to in his last post. I have
been working with Andrew for a couple of months
now and have learnt a great deal from him, as well
as from from my own experiments with the "scaled
up" burner I have built, based on his design. I
have, of course, also learnt an enormous amount
from all of you who post here and now, as my
learning curve flattens, I find the going a little
easier.

I do not yet have the experience in combustion
technology to contribute a great deal but I have
made a few observations and I am starting to form
opinions of which I will throw a couple into the
"pot"

1. Whether making charcoal or producing heat,
first dry your fuel, then dry it and then dry it
again!

2. For best and controllable heat production,
forced draft, top down burning is the method of
choice where possible unless using all but the
driest of fuels and even then I feel it has
distinct advantages over normal aspiration.

I look forward to my future time on the list and I
will no doubt meet a few more of you on my various
travels, or indeed here in England when (and if)
any of you are over here.

Kind regards to you all.

David C. Reynolds-Lacey
Areley Wood Enterprises

From Carefreeland at aol.com Mon Apr 15 02:36:31 2002
From: Carefreeland at aol.com (Carefreeland@aol.com)
Date: Tue Aug 31 21:37:46 2004
Subject: Water as a byproduct of combustion...
Message-ID: <62.1e224309.29ec150c@aol.com>

Dear Kevin, Tom, Ron, and all stovers,
As far as the subject at hand. Greenhouse effect produced by CO2 has
a separate effect from that cooling produced by clouds.
When additional water is released into the air, the resulting higher
dew points not only add clouds but rain as well. Once water falls as rain, it
may be absorbed by soil instead of re-evaporating. This keeps a mostly
constant cloud cover percentage. This can vary with the location of the
moisture release. Condensation releases heat stored in the vapor state also
offsetting the cooling effects, but often at higher altitudes.
This is obviously a complex puzzle needing much more study. When the
weather service ignores the correct prediction of severe weather by anything
but their tried and proven methods, how can they ever comprehend this study.
I have shown time and again that the temperature of the water in the soil has
an effect on the atmosphere with sometimes devestating effects.
I appreciate all of the support and interest in my work. To Ron L.
And all those waiting responses, I request your patience as this is a very
pivotal point in my business. I have just hired a skilled helper and it is
like training a whole new crew when there is only two of us. The approach of
mothers day is also a yearly pressure point with our care of landscaping at
restaurants. That day is often the busiest of the year for eating out. The
significant local rain and fluctuating weather has only added pressure to the
schedule.
I am still reading all posts on many lists and will respond as I find
time. Just reading takes up most of my on line time now.
Great remarks by Crispin and all responses are very well thought out.
Can we break this up a little more next time though? My brain was steaming
after reading some of these long letters.
David, glad to see you step up to the plate for a swing (baseball
reference) your work will certainly be appreciated here on the stoves list.
Glad to see the lull in posting has ended on many lists. Even
biodigestion has been very active. I learn something new there daily.
Keep posting,
Dan Dimiduk

From ronallarson at qwest.net Mon Apr 15 04:25:00 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:46 2004
Subject: Another Lurker pop's up!
In-Reply-To: <3CBAA511.A1738498@virgin.net>
Message-ID: <002c01c1e481$4d40efe0$abe46641@computer>

David:

1. It sounds like you have found a wonderful vocation - and have found
excellent advice off-list. I don't think we should worry about lurking or
not - but glad to hear your message (and from any others at any time)..

2. One way to hurt your operation is to ask you too much and have too many
competitors join your approach. On the other hand, you have given the crux
of your approach and maybe you won't mind others coming along after you.

3. Therefore please consider this in terms of asking for more information
that might help developing countries - but in developed countries as well if
you wish. What part of what you are exploring is NOT appropriate right away
for those areas of Africa where you have spent the most time? As an
example - how important is the coppicing option? Or, charcoaling?

4. You are obviously very interested in charcoaling. What options have you
discovered for using the pyrolysis gases other than the drying approach of
Andrew?

5. Are there any more operational questions for the list?

6. Your list of conclusions was admirably short (drying and a forced-air,
top-down recommendation). Any others in a second tier?

7. Thanks for your message. Good to have your expertise with us.

Ron

----- Original Message -----
From: David Reynolds-Lacey <d.rl@virgin.net>
To: <stoves@crest.org>
Sent: Monday, April 15, 2002 4:01 AM
Subject: Another Lurker pop's up!

> Hello Stovers,
>
> I have been lurking on the list for several months
> now so it's about time to say hello to all of you.
> I found the list during a search for "charcoal
> retorts".
>
> First, a little about myself. I am 58 and live in
> Worcestershire, England, I retired 10 years. ago
> from from my telecommunications business and have
> dedicated my time since then to restoration and
> conservation work. Five years ago I purchased a
> much neglected and overgrown 150 acre semi natural
> ancient woodland site near to my home and set
> about restoring it using traditional methods. The
> site has a long history in charcoal making
> (especially for gunpowder production), small scale
> coal mining and brick making. After spending 3
> years restoring some of the infrastructure I began
> coppicing work, with just 5 acres done to date. So
> far I have only been able to produce firewood and
> charcoal but when the coppice is in proper
> rotation I intend to engage in a variety of
> traditional woodland crafts. I am now able to
> employ 2 full time workers and have one student
> trainee from a local agricultural college, I will
> provide more training places as we progress. It
> is my aim to make my operation completely self
> sustaining, both financially and energy-wise and
> my current energy scheme is to produce heat and
> electrical/mechanical power entirely from forest
> debris using all equipment that I have built
> myself. I care passionately about the environment
> and having spent time in some developing
> countries, especially South Africa, I would like
> to think my work could also be of benefit in these
> areas. My primary skills are in business
> management, sales and marketing but I am a general
> "all rounder" with a strong bias towards
> mechanical engineering.
>
> Whilst I haven't posted to the list before, I
> have contacted 3 list members off list. The first
> was Dan Dimiduk, who as well as giving me a great
> deal of help and information also put me in
> contact with Ken Boak, now Ken and I are looking
> at projects involving flash steam, Stirling
> engines and a "stoves" related project, which is
> current. I also contacted Andrew Heggie and I am
> the "Lurker" referred to in his last post. I have
> been working with Andrew for a couple of months
> now and have learnt a great deal from him, as well
> as from from my own experiments with the "scaled
> up" burner I have built, based on his design. I
> have, of course, also learnt an enormous amount
> from all of you who post here and now, as my
> learning curve flattens, I find the going a little
> easier.
>
> I do not yet have the experience in combustion
> technology to contribute a great deal but I have
> made a few observations and I am starting to form
> opinions of which I will throw a couple into the
> "pot"
>
> 1. Whether making charcoal or producing heat,
> first dry your fuel, then dry it and then dry it
> again!
>
> 2. For best and controllable heat production,
> forced draft, top down burning is the method of
> choice where possible unless using all but the
> driest of fuels and even then I feel it has
> distinct advantages over normal aspiration.
>
> I look forward to my future time on the list and I
> will no doubt meet a few more of you on my various
> travels, or indeed here in England when (and if)
> any of you are over here.
>
> Kind regards to you all.
>
>
> David C. Reynolds-Lacey
> Areley Wood Enterprises
>
>

From Tami.Bond at noaa.gov Mon Apr 15 05:08:01 2002
From: Tami.Bond at noaa.gov (Tami Bond)
Date: Tue Aug 31 21:37:47 2004
Subject: Water as a byproduct of combustion...
Message-ID: <1bdf915591.155911bdf9@pmel.noaa.gov>

Tom,

You would have to draw me out... ;-)

> I have long been puzzled by the emphasis on carbon dioxide as a
> greenhousegas. Water it the primary greenhouse gas...

The Earth's temperature is higher than one would expect without any
gases in the atmosphere. It's true that water vapor is the primary
cause. It's also generally accepted that human activity has little
effect as the major controlling processes are not releases by people
but the hydrologic cycle. The water vapor we release by burning coal,
wood or hydrogen doesn't change the concentration of water vapor in the
atmosphere by much.

Human activity does have an effect on CO2. The processes controlling
its concentration are uptake by plants (short time scale), uptake by
ocean (long time scale), weathering of rock (really long time scale) in
addition to what we dump in.

Isn't the water vapor greenhouse effect swamping any comparable effects
of CO2? Nope. That's because water vapor absorbs at different
wavelengths than CO2 does. The wavelengths that water vapor affects are
closer to saturated-- that is, H2O is already absorbing most of the
radiation at those wavelengths. If you add more H2O, the effect on
radiation is fairly small, just because there's not a lot more
radiation to absorb.

On the other hand, CO2 (and other greenhouse gases) absorbs at
different wavelengths where there is a nearly open 'window'. A small
amount can make a large difference. The question of 'climate change'
involves not what is absorbing the most radiation (water vapor is the
clear winner) but what is tipping the balance from its previous state
(other greenhouse gases).

The H2O-vapor wavelengths aren't completely saturated; hence the 'water
vapor feedback' effect. That is, if/as things get warmer, there ought
to be more water vapor in the atmosphere, and that will contribute to
even more warming-- but again, the warming per molecule of H2O is quite
a bit smaller than warming per molecule CO2.

Yes, Dan! Soil moisture, evaporation, condensation (or at least
parameterizations thereof) are in the climate models! Modelers have a
terrible time with convection processes because they are so small
compared to the modeling grids, but they're working on it. But these
models are on a very crude scale, maybe okay (or not??) for predicting
long-term trends, but certainly not with the resolution required for
daily weather predictions.

Tami

From psanders at ilstu.edu Mon Apr 15 06:57:34 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:47 2004
Subject: lightly forced draft Re: Another Lurker pop's up!
In-Reply-To: <3CBAA511.A1738498@virgin.net>
Message-ID: <4.3.1.2.20020415104702.018802d0@mail.ilstu.edu>

Dear Stovers, especially David and Andrew

<<<At 11:01 AM 4/15/02 +0100, David Reynolds-Lacey wrote:
<<<Hello Stovers,
I have been lurking on the list for several months now
... snip...
<<< I also contacted Andrew Heggie and I am
the "Lurker" referred to in his last post. I have
been working with Andrew for a couple of months
now and have learnt a great deal from him, as well
as from from my own experiments with the "scaled
up" burner I have built, based on his design.>>>
...end of snip..

And Andrew wrote earlier:

<<<It is possible though, with top lighting and stoking if dry kindling
is used as a starter. A number of the list can vouch for this,
including the lurker who has scaled up and implemented a lightly
forced draught device based on my design, CO down to 150ppm at >50kW(t)
burning freshly cut hazel chips.>>>

When Andrew mentioned David's work, I became curious about the "lightly
forced draft" and the device based on Andrew's design.

IF (please note the "IF") that information is able to be shared either to
the whole Stoves list or to individuals who agree to not divulge it (I do
so agree), would Andrew please send it and would David please provide
comments. (IF restricted information, please make that clear in order to
avoid any confusion.)

In my work on the Juntos stoves (plural), the issue of draft is extremely
important. Anything from natural draft to mechanical pumps to electrical
blowers could be important in the various segments of societies where
different traditions and financial resources must be taken into consideration.

Paul

From tombreed at attbi.com Mon Apr 15 07:01:29 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:47 2004
Subject: Water as a byproduct of combustion...
In-Reply-To: <1bdf915591.155911bdf9@pmel.noaa.gov>
Message-ID: <00d101c1e496$35dc4560$4bc0fd0c@TOMBREED>

Dear Tami:

You always add something new to the discussion ... thanks.

Granted that not all molecules absorb the same, I need to find a table of
total absorbtions for each species.

Puzzled. Are you saying that additional water vapor (forget clouds for now)
doesn't absorb proportionally to initial amounts? That water vapor
absorbtion is non-linear at the concentrations in the atmosphere (obviously
becomes non-linear as absorbtion approaches 100%). Are you saying that
absorbtion of radiation in one part of the IR spectrum gives different
heating than in another nearby part? Are you saying that the contribution
of 6-8 Gtons of CO2/yr are significant relative to the absorbtion of the
500,000 Gtons of water vapor in the air?
~~~~~~~~~
Then of course there is the long term question of whether we want to avoid
global warming at the risk of the overdue glaciation. (Typical interglacial
warming - 10,000 years; we are 12,000 years since last glacier).
~~~~~~~~~~
Have you read any of the "Earth's Children" series by Jean Auel, taking
place during the interglacial period of 25,000-30,000 years ago? Clan of
the Cave Bear is the best known, but there are three others and a new one
due this month after a hiatus of 15 years. I got started late reading them
and just finished "The Mamouth Hunters". Gives one a more global
perspective.

Your pal, TOM REED

----- Original Message -----
From: "Tami Bond" <Tami.Bond@noaa.gov>
To: "Tom Reed" <tombreed@attbi.com>
Cc: <stoves@crest.org>
Sent: Monday, April 15, 2002 8:07 AM
Subject: Re: Water as a byproduct of combustion...

>
> Tom,
>
> You would have to draw me out... ;-)
>
> > I have long been puzzled by the emphasis on carbon dioxide as a
> > greenhousegas. Water it the primary greenhouse gas...
>
> The Earth's temperature is higher than one would expect without any
> gases in the atmosphere. It's true that water vapor is the primary
> cause. It's also generally accepted that human activity has little
> effect as the major controlling processes are not releases by people
> but the hydrologic cycle. The water vapor we release by burning coal,
> wood or hydrogen doesn't change the concentration of water vapor in the
> atmosphere by much.
>
> Human activity does have an effect on CO2. The processes controlling
> its concentration are uptake by plants (short time scale), uptake by
> ocean (long time scale), weathering of rock (really long time scale) in
> addition to what we dump in.
>
> Isn't the water vapor greenhouse effect swamping any comparable effects
> of CO2? Nope. That's because water vapor absorbs at different
> wavelengths than CO2 does. The wavelengths that water vapor affects are
> closer to saturated-- that is, H2O is already absorbing most of the
> radiation at those wavelengths. If you add more H2O, the effect on
> radiation is fairly small, just because there's not a lot more
> radiation to absorb.
>
> On the other hand, CO2 (and other greenhouse gases) absorbs at
> different wavelengths where there is a nearly open 'window'. A small
> amount can make a large difference. The question of 'climate change'
> involves not what is absorbing the most radiation (water vapor is the
> clear winner) but what is tipping the balance from its previous state
> (other greenhouse gases).
>
> The H2O-vapor wavelengths aren't completely saturated; hence the 'water
> vapor feedback' effect. That is, if/as things get warmer, there ought
> to be more water vapor in the atmosphere, and that will contribute to
> even more warming-- but again, the warming per molecule of H2O is quite
> a bit smaller than warming per molecule CO2.
>
> Yes, Dan! Soil moisture, evaporation, condensation (or at least
> parameterizations thereof) are in the climate models! Modelers have a
> terrible time with convection processes because they are so small
> compared to the modeling grids, but they're working on it. But these
> models are on a very crude scale, maybe okay (or not??) for predicting
> long-term trends, but certainly not with the resolution required for
> daily weather predictions.
>
> Tami
>
>
>
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200204/
> http://crest.org/discussiongroups/resources/stoves/
> >
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
> >
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
> >
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
> >
> For information about CHAMBERS STOVES
>
>http://www.repp.org/discussiongroups/resources/stoves/Chambers/Chambers.htm
>

From tami.bond at noaa.gov Mon Apr 15 07:55:12 2002
From: tami.bond at noaa.gov (Tami Bond)
Date: Tue Aug 31 21:37:47 2004
Subject: Water as a byproduct of combustion...
In-Reply-To: <1bdf915591.155911bdf9@pmel.noaa.gov>
Message-ID: <3CBB05D3.5D3A50C1@noaa.gov>

Dear Tom,

> Puzzled. Are you saying that additional water vapor (forget clouds for now)
> doesn't absorb proportionally to initial amounts? That water vapor
> absorbtion is non-linear at the concentrations in the atmosphere (obviously
> becomes non-linear as absorbtion approaches 100%).

Yes, that's what I'm saying. Some of those windows are at 100%
saturation, but not all.

> Are you saying that
> absorbtion of radiation in one part of the IR spectrum gives different
> heating than in another nearby part?

No, I'm saying that there is still radiation left to absorb in some
parts of the spectrum, not in others. Absorption should all have more or
less the same effect.

> Are you saying that the contribution
> of 6-8 Gtons of CO2/yr are significant relative to the absorbtion of the
> 500,000 Gtons of water vapor in the air?

Sort of. Again, it's relative to what existed 'before', in the
'untouched' state (whatever that was). No question that H2O has a huge
effect: the planetary temperature would be something like 30 K lower
without it. But there is some radiation, e.g. 2-2.5 um, that H2O can't
touch and CO2 can. And there are some windows, e.g. 6-7 um, that are
completely saturated by H2O and it doesn't matter how much more H2O you
put up there. So yes, CO2 can have an effect even with all that water
vapor up there.

Another issue is that controls on H2O are mostly *not* anthropogenic.
The H2O concentration is largely governed by temperature, convection,
rainfall-- natural processes. The CO2 concentration does have a
substantial dependence on anthropogenic source strength. So again, 'we'
can change concentration of CO2, while keeping H2O more or less
constant, and the radiative change from 'previous' conditions is mainly
due to CO2. (Well, this is a pretty simplistic picture... I keep being
tempted to throw caveats in...)

> Then of course there is the long term question of whether we want to avoid
> global warming at the risk of the overdue glaciation. (Typical interglacial
> warming - 10,000 years; we are 12,000 years since last glacier).

Climate will change regardless of what we do. To me, the question is how
fast we want to change it, and whether the fact that it would change
anyway means that we should just do whatever we want. The
'geoengineering' possibility seems like a red herring to me; if one
pooh-poohs CO2 as a problem for current climate, how can one hope to
believe that it will offset some theoretical future cooling? We are
getting into philosophical debate here, which I am happy to continue-- I
learn something every time I go through it, and I can't stop myself
wondering about what we 'should' do!-- but we should probably take it
off-list.

> Have you read any of the "Earth's Children" series by Jean Auel, taking
> place during the interglacial period of 25,000-30,000 years ago?

Yes, I have read the first 3. Liked 'Cave Bear' the best because it
seemed to have the most focus on culture and least on 'anthroporn' but
they were all enjoyable nonetheless.

Have to get some work done now!

Tami

From psanders at ilstu.edu Mon Apr 15 08:26:22 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:47 2004
Subject: Gasifier fundamental question
In-Reply-To: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>
Message-ID: <4.3.1.2.20020415114116.018701b0@mail.ilstu.edu>

At 12:04 PM 4/14/02 -0300, Kevin Chisholm wrote:
>Dear Dr. Karve
>I think Paul is asking the wrong question, when he asks if it makes any
>difference where the fuel is being burned.
>
>The answer to that question is, to me, in my blatant humble opinion, is very
>obvious: It must be burned where the stove design requires it to be burned.

Some observations from Paul:
1. It is not "where the stove design requires...", but rather "where the
stoveS designS require it to be burned." We must think of multiple stoves
(plural). Even the very poor households generally have two or more places
and arrangements for burning different fuels (and we all agree that
charcoal is a different fuel than is wood or biomass) or for different
conditions of weather, etc.

2. The distance from the fuel to the pot is extremely important. Kevin
correctly points out the negative side of flames licking the bottom of the
pot, and therefore advocates more height in the stove structure for that
same heat level of fire. But charcoal needs to be close to the pot if it
is to be well used. Therefore, SOMETHING must move. Move the pot to a
lower position close to the charcoal; or move the charcoal to a higher
position close to the pot; or move the charcoal to a different stove (or
save it for use later) where the correct distance can be
maintained. Almost always, something must move.

3. I said "almost always" because of (at least) two situations:
3.a. The cook might be very happy with the low heat reaching the
pot that is "too high in distance" from the charcoal, as in just wanting to
simmer the pot after using the initial high heat to get the pot hot.
AND
3.b Tom Reed's turbo stove with blower can kick in the extra air
to burn the charcoal after the pyrolysis gasification has ended, and the
pot stays in the same place in relation to the fuel. BUT:
The BUT is that the extra air forced onto the charcoal essentially
creates a forge (or some other name for a very high temperature forced-air
stove). I tried that with one of my "tincanium" Juntos stoves and
promptly melted/vaporized/destroyed the aluminum air pipe in the bottom
under the fuel grate through which the primary air was being
forced. Furthermore, the higher heat would take a major toll on the life
span of the gasifier can. (This is in contrast to the relatively lower
temperatures in the can needed during the gasification stage.) The
alternative is to make a more-resistant-to-high-temperatures gasifier, and
we know that such metals and thicknesses do exist. But that raises the
cost of the stove (and also the cost to provide some form of forced
draft). It also raises the question of added "mass" that needs to be
heated, something that Dean and Larry do not favor (but they do recognize
that some material is needed, and maybe this increase in mass is not very
important.)

4. Therefore, I have the current opinion that removing the charcoal after
gasification of the biomass fuel is a highly appropriate procedure.

5. Addendum concerning Ronal's earlier comment about smoke at the end of
the gasification stage: When I have a decent chimney in place, or when
another combustion unit (such as an open-bottom rocket stove) is above the
gasifier, the natural draft keeps the gasification going all the way to the
end (I am using pellets and I was running at the not-quantified "plenty of
air" setting). I let it run 30 to 60 seconds extra, and when I pull out
the gasifier, I have no smoke and only glowing coals that I dump into an
old paint can and reseal.

6. In my work I am doing almost nothing concerning charcoal except to
witness that the gasifier does a nice job of creating the
charcoal. Basically, I have no difficulties with the ideas of charcoal
production and I am glad that folks like Ron and AD and Dan D. are able to
see justification in the charcoal side of things.

Paul

From hseaver at cybershamanix.com Mon Apr 15 09:07:08 2002
From: hseaver at cybershamanix.com (Harmon Seaver)
Date: Tue Aug 31 21:37:47 2004
Subject: Gasifier fundamental question
In-Reply-To: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>
Message-ID: <20020415180609.GA27179@cybershamanix.com>

On Mon, Apr 15, 2002 at 12:34:05PM -0500, Paul S. Anderson wrote:
> 3.b Tom Reed's turbo stove with blower can kick in the extra air
> to burn the charcoal after the pyrolysis gasification has ended, and the
> pot stays in the same place in relation to the fuel. BUT:
> The BUT is that the extra air forced onto the charcoal essentially
> creates a forge (or some other name for a very high temperature forced-air
> stove). I tried that with one of my "tincanium" Juntos stoves and
> promptly melted/vaporized/destroyed the aluminum air pipe in the bottom
> under the fuel grate through which the primary air was being

You don't really need the forced draft to burn up the charcoal, at least
with my experiments it all seemed to burn quite nicely if I gave it a little
more open draft at the end. However, my IDD stove had a much taller upper
section -- "chimney" effect -- which of course increases the natural
draft. Perhaps more experiments are in order with various length top sections --
to get the optimum draft without getting the pot too far away from the pyrolysis
area. Also more insulation in the upper part might make the distance between the
pyrolysis area and the pot less relative.
I also had no problems with melting anything, but my coffee can was
insulated with perlite/cement refractory, and it also had a stainless grate.

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

From psanders at ilstu.edu Mon Apr 15 09:48:22 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:47 2004
Subject: Gasifier fundamental question
In-Reply-To: <002501c1e2b3$8fc59ac0$52e80fc4@home>
Message-ID: <4.3.1.2.20020415134727.01881410@mail.ilstu.edu>

>On Sat, 13 Apr 2002 08:21:28 +0200, "Crispin" <crispin@newdawn.sz>
>wrote:
> >"...the secondary air supply for top-lit stoves has not seemed to need a
> >separate control..."

>and At 10:24 PM 4/13/02 +0100, AJH wrote in reply:
>It is also a function of the earlier statement that offgas from an idd
>stove is realtively constant, [[**MARK by Paul**]] it is not true when a
>toplit stove is
>allowed to turn into an updraught stove. I think there is some
>confusion between top lit and idd.

I can agree that there is confusion. Andrew, can you please explain your
statements above that come after the [MARK] and help me understand the
differences.

Thanks,

Paul

From kchisholm at ca.inter.net Mon Apr 15 17:14:37 2002
From: kchisholm at ca.inter.net (Kevin Chisholm)
Date: Tue Aug 31 21:37:47 2004
Subject: Gasifier fundamental question
In-Reply-To: <000201c1e383$d4b2e7c0$8351c5cb@adkarvepn2.vsnl.net.in>
Message-ID: <00e001c1e4ec$2fa14f00$ad19059a@kevin>

Dear Paul
Subject: Re: Gasifier fundamental question

...del...>
> Some observations from Paul:
> 1. It is not "where the stove design requires...", but rather "where the
> stoveS designS require it to be burned." We must think of multiple
stoves
> (plural). Even the very poor households generally have two or more places
> and arrangements for burning different fuels (and we all agree that
> charcoal is a different fuel than is wood or biomass) or for different >
conditions of weather, etc.

You are on the right track with a plurality of stoves for a plurality of
purposes.

The problem is that the more versatile a stove must be, the more compromises
that have to be made. Invariably one pays a big price in performance and
efficiency for universality. The more specific the design parameters that
the designer employs, the better th job he can do at accomplishing that
task.
>
Best wishes.

Kevin Chisholm

From d.rl at virgin.net Tue Apr 16 02:25:19 2002
From: d.rl at virgin.net (David Reynolds-Lacey)
Date: Tue Aug 31 21:37:47 2004
Subject: Another Lurker pop's up!
In-Reply-To: <3CBAA511.A1738498@virgin.net>
Message-ID: <3CBC0A09.5332F04F@virgin.net>

Stovers,

I think this reply covers questions raised by Ron and Paul. Tom, you asked at
the end of your email "But how did you know?" - Ans. - I didn't, I just tried
it to find out.

Ron Larson wrote:

> 2. One way to hurt your operation is to ask you too much and have too many
> competitors join your approach. On the other hand, you have given the crux
> of your approach and maybe you won't mind others coming along after you.

I consider my own work now as being philanthropic and not commercially
orientated (I've left all that behind) therefore I am pleased to share MY OWN
ideas providing that others don't make profit from them, however please bear in
mind in this instance that I am working with someone else's initial design in
order to help them out whilst also helping myself and eventually others, I am
therefore restricted as to what information I can divulge at this stage.

>
> 3. Therefore please consider this in terms of asking for more information
> that might help developing countries - but in developed countries as well if
> you wish. What part of what you are exploring is NOT appropriate right away
> for those areas of Africa where you have spent the most time? As an
> example - how important is the coppicing option? Or, charcoaling?

Please don't misunderstand my mention of visits to developing countries, the
purpose for my past visits has been either (other) business related or as a
tourist, and not related to any work of the type I do now, although I have
always wandered from the "normal visitor" paths to find out what is going on in
the REAL country I'm visiting. I will now of course on future visits seek out
and visit stoves/sustainable energy related organisations or individuals, with
this in mind, I expect to be in SA during late June early July.

Coppicing is most important to me - growing and harvesting fuel is no different
to growing and harvesting food, therefore traditional crop tending skills with a
minimum extra training is all that is required. I may be out on a limb here
(pardon the unintended pun) because I am not an expert on the type of trees
that grow in say, for example, Africa or whether they can be coppiced or indeed
are already coppiced, perhaps someone can answer this. To my mind short rotation
coppice is probably the best source of "managed" sustainable fuel, a coppiced
tree (or a pollarded one for that matter), correctly maintained, will produce
several tonnes of fuel for centuries and asks comparatively little in return.
The fuel produced is easily harvested and handled, it requires very little
preparation and with the correct burner it can be burnt wet (sappy) or dry,
either as faggots or chips. I am not convinced that charcoal, burnt in the
normal way (i.e producing radiant heat) is the way forward for heating cooking
pots, as moving the pot or the fuel bed involves more operator intervention, I
am a great believer in "fire and forget" with the only adjustment required being
to the air supply either manually or automatically and the occasionally addition
of fuel. I will shortly be posting some questions about cooking practices and
any replies will help me expand some ideas that I have - or kill them
completely!

> 4. You are obviously very interested in charcoaling. What options have you
> discovered for using the pyrolysis gases other than the drying approach of
> Andrew?

I produce charcoal (inter alia) only to generate income, by selling it into the
local barbecue market, Areley Wood Enterprises is set up as a not-for-profit
organisation, limited (with an intentional lower case "l") only by my personal
guarantee, It must be eventually financially self sustainable as well as energy
self sustainable in order to prove my theory. I will continue to produce
charcoal by the retort method except for occasional "pollution" days (sorry
Ron!) when we demonstrate to the public the making of charcoal in traditional
turf clamps. I will be using some of the the pyrolysis gasses in a recirculating
steam dryer for firewood logs and some will be recycled back into the retort,
with any excess being burnt to produce flash steam for a turbine and/or heat for
a Stirling engine.

>
> 5. Are there any more operational questions for the list?

Now I have broken the ice I will probably be posting more questions than answers
but I think it will be a while yet before I can consider becoming a net
contributor.

> 6. Your list of conclusions was admirably short (drying and a forced-air,
> top-down recommendation). Any others in a second tier?

All tests have been done with batch loading using what could be described as a
biomass dryer/gassifier/burner, the next stage is to design a fuel injection
system. I still intend to "play around" a little with air feed and combustion
chamber shape but we do have a burner that works as it is now. I will be working
with Ken Boak on a scaled down version for use as a cooking stove in the near
future.

David

From RSamson at reap-canada.com Tue Apr 16 08:41:08 2002
From: RSamson at reap-canada.com (RSamson@reap-canada.com)
Date: Tue Aug 31 21:37:47 2004
Subject: Update on REAP's stove program
Message-ID: <3CBC6272.6A8A874@reap-canada.com>

Dear stovers,

Here is an update from the Philippines on our current efforts with the
Mayon Turbo stove. We will be submitting a proposal to the Shell
Foundation for upscaling production in 5 countries and are looking for
partners to work with if any of you are interested or have suggestions.
Those of you waiting for a stove we will be shipping them shortly, sorry
for the delay but we made a few more modifications and we wanted you to
have the latest models.

This trip I have been working with our partners to optimize the smaller
model the Mayon Turbo 6000 and to reduce fuelbed fires in both models.
We have observed that there is somewhat more difficulty starting a fire
with the smaller model and that it tends to get a lot more fuelbed fire
activity. We have nearly eliminated fuelbed fires by putting a heat
shield at the base of our centre cone. This is essentially an upside
down skirt (4" in height on the 6000 model and 5" in height on the 7000
model) attached to the base of the centrepiece. It deflects the heat
away from the rice hull sitting in the hopper. It seems to work great
and if we just add fuel periodically it has eliminated the need for
stirring the rice hull in the hopper as a means to prevent or extinguish
fuelbed fires. On the larger model, fuelbed smoldering is basically
eliminated with this addition. We have also been finetuning the air.
Our quality of combustion is now rather impressive for such a low cost
cooker. We have a non-luminescent flame through the day and a blue
flame when cookingin the evening. With a limited amount of training, no
smoke events are experienced during the entire cook. One thing we have
noted is that there needs to be a good quality control when producing
the stoves. We have produced about 3700 to date. The distance the ash
pan is attached at the base of the hopper and the distance the
centerpiece is attached above the ashpan need to be consistent,
otherwise ease of operation and combustion quality can be affected.

Some other secondary issues we are examining is to assess alternative
materials for manufacturing the stove. Presently we are using 16 gauge
steel. On the old stove we are having some reports of the centrepiece
rusting out after about 18 months. Seems that the rice pot boils over
from time to time and helps rusts out the centerpiece. This may be
partly eliminated with the Mayon Turbo as the heat output is much less
erratic than the former model which had widely fluctuating heat output
(stove users simply opened up holes through the bottom of the ashpan to
avoid smoke).

We have also done a limited amount of testing with sawdust. Seems to
work best if mixed with rice hull. The stove appears to need extra air
if burning sawdust and it doesn’t flow as nicely. I would suggest
putting in three air injectors as a starting point for anyone looking to
burn sawdust. One could simply be blocked if burning rice hull. Hoping
to test coffee shells shortly.

Well I hope some of you have built stoves and are getting some results.
It would be rather good to hear about your efforts.

Roger Samson

Resource Efficient Agricultural Production-Canada
Box 125, Maison Glenaladale,
Ste Anne de Bellevue,
Quebec, CANADA
H9X 3V9
WWW.REAP-CANADA.COM
Tel. (514) 398-7743
Fax (514) 398-7972

"Creating ecological energy, fibre and food production systems"

From andrew.heggie at dtn.ntl.com Wed Apr 17 13:01:16 2002
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:47 2004
Subject: lightly forced draft Re: Another Lurker pop's up!
In-Reply-To: <3CBAA511.A1738498@virgin.net>
Message-ID: <88qrbug3nglr36d6falenl8sl3oeiplhk5@4ax.com>

On Mon, 15 Apr 2002 11:05:35 -0500, "Paul S. Anderson"
<psanders@ilstu.edu> wrote:

>IF (please note the "IF") that information is able to be shared either to
>the whole Stoves list or to individuals who agree to not divulge it (I do
>so agree), would Andrew please send it and would David please provide
>comments. (IF restricted information, please make that clear in order to
>avoid any confusion.)

It's a bit early to say which way this will go at present so I will
refrain from further comment. It is very simple, possibly obvious, but
contains proprietary techniques and will need a lot of work before it
can be deployed as a self standing cooking stove. I was never able to
progress it from my "heath Robinson" contraption Ronal saw until David
R-L took an interest. In its larger form it forms but one part of my
clean charcoal making scheme.

AJH

From andrew.heggie at dtn.ntl.com Wed Apr 17 13:02:00 2002
From: andrew.heggie at dtn.ntl.com (AJH)
Date: Tue Aug 31 21:37:47 2004
Subject: Gasifier fundamental question
In-Reply-To: <002501c1e2b3$8fc59ac0$52e80fc4@home>
Message-ID: <5oqrbu03pvhhbl4l40p7shmvd0blannri8@4ax.com>

On Mon, 15 Apr 2002 13:56:22 -0500, "Paul S. Anderson"
<psanders@ilstu.edu> wrote:

>
>>and At 10:24 PM 4/13/02 +0100, AJH wrote in reply:
>>It is also a function of the earlier statement that offgas from an idd
>>stove is realtively constant, [[**MARK by Paul**]] it is not true when a
>>toplit stove is
>>allowed to turn into an updraught stove. I think there is some
>>confusion between top lit and idd.
>
>I can agree that there is confusion. Andrew, can you please explain your
>statements above that come after the [MARK] and help me understand the
>differences.

Simply that many fires can be toplit, once the fire is established
(secondary burning) it can be fed and treated as "normal". The idd is
a special case of toplighting with primary air control. I believe you
published pictures of a toplit (idd) unit with a flame which was
orange with deep purple feathery edges. This showed a diffuse flame in
which the secondary air supply could never provide enough air at the
gases interface for complete combustion. With idd the primary air is
restricted so that pyrolysis products remain constant, combustion
takes place as a diffuse flame.

If you allow the pyrolysis front to rapidly move down the stack of
fuel and then start burning in an updraught fashion you are able to
have the benefits of a clean toplit start with the familiarity of a
traditional fire, which Crispin may be happy with. It will however
always be a slower start up, I think, as the toplit fire has only
radiation and conduction to feedback heat to the fuel stack, the
updraught fire has convection from combustion products in addition.

AJH

From dstill at epud.net Mon Apr 22 11:47:00 2002
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:37:47 2004
Subject: Fw: Constant area
Message-ID: <000c01c1ea68$40180960$831d66ce@default>

Dear Stovers,

I've been working on how to even the temperatures on a griddle (comal) so
that tortillas don't burn in one place and stay raw in another. When using a
large open fire the heat is generalized over a large surface. But placing a
stove's smaller diameter opening under the griddle can create an unwanted
hot spot. (If we're boiling beans on top of the griddle you want to put the
pot over as hot a spot as can be created and hope that the rest of the
griddle is at room temperature but making tortillas is different.)

My mentor, Larry Winiarski, discovered a long time ago that tapering the gap
under a pot, decreasing towards the rim, assists better heat transfer and
therefore more even temperatures. My recent experiments show this to be so.
I asked Ken Goyer, Aprovecho consultant, to write up for Emma in Uganda how
to calculate the cross sectional area under a pot. Larry starts a design out
by keeping the same cross sectional area throughout the whole stove allowing
the hot flue gases to flow unimpeded. This seems to be a good rule of thumb.

But, Emma is using an external chimney in her design which adds more draft
so gaps can be decreased a bit which helps heat transfer all the more.
Following is Ken Goyer's explaination of one of the important Rocket design
principles:

The way to calculate the height of the gap under the pot in
order to maintain a constant cross section is as follows:
First, figure out the area of the combustion chamber. If the
combustion chamber is five inches in diameter then the area is A=pie r
squared, or 3.14 x 2.5in. x 2.5in. = 19.6 square inches. 19.6 square
inches of gasses are proceeding up the rocket elbow and we want to
maintain the draft and not change it's velocity so we want to maintain
this cross section under the bottom of the pot as the gasses progress
outward toward the edge of the pot. At the top edge of the rocket elbow
the gasses are going to turn and follow the bottom of the pot. The five
inch diameter has a circumference of C = pie d or 3.14 x 5 inches =
15.7 inches. If this space were one inch high it would only be 15.7
square inches. But we need 19.6 square inches. So it needs to be higher
than one inch or 19.6 / 15.7 = 1.25 inches high over the edge of the
combustion chamber where the gasses are turning and flowing radially
under the pot. Now as the gasses go outward the circumference gets
bigger so the gap must get smaller in order to maintain the same cross
section. At 7 inches the circumference is C = pie x d or 3.14 x 7 = 22
inches. So the gap is 19.6 inches divided by 22 inches or .9 inches. At
9 inches the circumference is C = pie x d or 3.14 x 9 = 28 inches. 19.6
divided by 28 inches = .7 inches.
You can figure this height at any diameter under the pot. For
example if the pot was 20 inches in diameter circumference would be C =
pie x d or 3.14 x 20 = 63 inches and the gap would be 19.6 divided by 63
inches or .3 inches. You can figure this as precisely as you wish. You
can plot it for every inch of the diameter, or even every half inch. But
with three or four points you can get a good approximation of the cross
section at various diameters. I hope this helps to explain how to keep
the cross section equal under the pot so the combustion gasses can
maintain their velocity and scrub the pot at closely as possible.

Best
regards, Ken (and Dean)

From crispin at newdawn.sz Mon Apr 22 12:54:34 2002
From: crispin at newdawn.sz (Crispin)
Date: Tue Aug 31 21:37:47 2004
Subject: Constant area
Message-ID: <007e01c1ea47$ee9c8fe0$7ce80fc4@home>

Dear Ken (and Dean)

My late brother Andrew, a historian, would say that it it the historian's
role to say, "It is really not quite as simple as that," so I now quote
him.

>My mentor, Larry Winiarski, discovered a long time ago that tapering the
gap
>under a pot, decreasing towards the rim, assists better heat transfer and
>therefore more even temperatures.

I think the emphasis there should be on the words 'more even'.

Because of the nature of your application I suggest the follow for
consideration (not a total solution):

First, make the steel plate as thick as possible, especially as it is a
comercial application. The heat loss getting it hot in the morning is
amortized over a long cooking day and the cost will be well worth it if it
helps cook over a larger area. The thinner the plate the worse your temp
variations will be no matter what else you do.

Second, one of the simple ways to greatly reduce the temperature right over
the fire is to put another steel plate under that spot. This is not a
matter of thickening it, but of 'hanging' another plate with an air get
between them. The heat protection so provided varies with the distance it
stands off. Try a 200mm diameter 4mm plate 15mm down. The little plate will
get very hot (I would use some sort of stainless like an old pot bottom or
lid) but it will only pass a certain amount of heat through to the point on
the top directly over the fire.

This plate conserves heat in the flue gases so that as they get farther away
they are hotter than they used to be.

Third, as the gases get farther away they cool down and conduct less heat to
the plate. This has to be factored into your calculation making if FAR more
complicated. For example, if you follow the method you described, the gases
would drop from, say, 750C to 250C as it passes under the plate from center
to chimney. Clearly even though you are letting the gas touch the plate for
the same amount of time at each point by tinkering with the gap, you should
also have to slow it down so that it has more time to transfer remaining
heat to the plate as the temperature is lower and the heat transfer rate is
lower. Nifty, huh? So in fact the gap should be larger (to slow it down)
than the simple calculation of 'equal areas' (as I call that type of
solution).

Fourth, as the transfer of heat is greatly enhanced by turbulence, you
really should not have a smooth taper between two surfaces but rather have a
series of 'annular rings' each of which is progressively higher than the
previous (inner) one thus reducing the gap at that point only. This would
look like a stadium seating arrangement. One might call it a Stadium Flue
Control.

Now combine that idea with the change in depth to speed up the flue gases,
and you will have a series of donut-shaped chambers that get shallower
either towards the outside (or the inside - it is not yet clear). They will
create chambers where the heat can 'rest a while' to mix and then rush
through the gap to transfer heat to the plate. If the first ones are small
and shallow with a large clearance to the plate's underside, the hot gases
will speed by, and then as they cool down, they will linger longer
languishing around to dump their final heat upwards.

You can make these rings by planting a sheet metal strip into a clay
undersurface with the plate supported above.

Because the calculation is so complex, I suggest you simply start and
experiment a bit to see what you get. My suspicion is that you should be
able to use an inexpensive combination of a small reflector plate directly
above the fire and annular strips around it to move the majority of heat out
towards the periphery getting a large percentage of the plate to a
surprisingly even heat, given a steady fire.

Regards
Crispin

From kmbryden at iastate.edu Mon Apr 22 17:26:33 2002
From: kmbryden at iastate.edu (kenneth mark bryden)
Date: Tue Aug 31 21:37:47 2004
Subject: Constant area
In-Reply-To: <007e01c1ea47$ee9c8fe0$7ce80fc4@home>
Message-ID: <5.1.0.14.2.20020422203352.00b14368@localhost>

Crispin et al

I usually work in the lab and stay out of the spot light but I would like
to note that there are substantial downside issues for the solution that
Crispin suggests.

At 11:50 PM 4/22/2002 +0200, Crsipin wrote:

>First, make the steel plate as thick as possible, especially as it is a
>comercial application. The heat loss getting it hot in the morning is
>amortized over a long cooking day and the cost will be well worth it if it
>helps cook over a larger area. The thinner the plate the worse your temp
>variations will be no matter what else you do.

While the heat loss may be negligible in some applications, it is not in
all applications. In order to "smooth out" the temperature of the surface
the steel plate will need to be substantially heavier. Additionally the
heavier/thicker the plate the more heat capacity and the greater the
potential for injury to the user and the children, this occurs both during
use (the burn will go deeper - but I agree that they can get burnt on the
thinner top) and following cooking during the much longer cooldown period.
Remember that the top is much heavier.

>Second, one of the simple ways to greatly reduce the temperature right over
>the fire is to put another steel plate under that spot. This is not a
>matter of thickening it, but of 'hanging' another plate with an air get
>between them. The heat protection so provided varies with the distance it
>stands off. Try a 200mm diameter 4mm plate 15mm down. The little plate will
>get very hot (I would use some sort of stainless like an old pot bottom or
>lid) but it will only pass a certain amount of heat through to the point on
>the top directly over the fire.

This will significantly reduce the efficiency and hence the effectiveness
of the cooking surface and setup.

>This plate conserves heat in the flue gases so that as they get farther away
>they are hotter than they used to be.

Because the hot gases are kept away from the surface you allow slower
motion in the boundary layer reducing the heat transfer to the surface
relative to the scheme that Dean Still proposes. You also run the risk that
the flow of hot gases will not reattach to the surface of the grill
smoothly. The consequence of this is that more heat will end up in the
exhaust gas and be wasted. Or that you will have to do substantial amounts
of diddling to get everything to work right. This is in contrast to the
relatively simple technique proposed by Dean which he has tested. I would
note that keeping the area constant is not quite optimum, it is a good
first cut that can be implemented in the field with little effort.

>Third, as the gases get farther away they cool down and conduct less heat to
>the plate. This has to be factored into your calculation making if FAR more
>complicated. For example, if you follow the method you described, the gases
>would drop from, say, 750C to 250C as it passes under the plate from center
>to chimney. Clearly even though you are letting the gas touch the plate for
>the same amount of time at each point by tinkering with the gap, you should
>also have to slow it down so that it has more time to transfer remaining
>heat to the plate as the temperature is lower and the heat transfer rate is
>lower. Nifty, huh? So in fact the gap should be larger (to slow it down)
>than the simple calculation of 'equal areas' (as I call that type of
>solution).

No. if you slow it down the boundary layer thickens, the heat transfer
coefficient is reduced, and the problem gets worse. At the slower
velocities the flow may also become laminar. In fact a quick analysis
(conservation of energy at the plate surface) shows that you want the gases
to speed up toward the end, that is the optimum gap is smaller not larger.

>Fourth, as the transfer of heat is greatly enhanced by turbulence, you
>really should not have a smooth taper between two surfaces but rather have a
>series of 'annular rings' each of which is progressively higher than the
>previous (inner) one thus reducing the gap at that point only. This would
>look like a stadium seating arrangement. One might call it a Stadium Flue
>Control.

there are a couple of problems with this idea. Heat transfer is enhanced by
turbulence but the annular rings with which I think you are trying to trip
the flow into turbulence will only cause the flow to separate from the
surface. Remember that the Reynolds number is the primary driver for
turbulent flows and so trip wires only help flow that are already inclined
to be turbulent. If the flow is too slow the viscosity of the fluid will
return it to laminar. A micro pattern stamped on the surface may increase
heat transfer but it would require some testing and would likely be
difficult to implement in the field and would become gunked up shortly
after use began. Also it is likely the pattern needed to ensure turbulence
probably varies with the velocity of the hot gases. Since turn down is an
important function of a stove this could be a problem.The rings could be
used as fins to increase heat transfer but testing and computational
modeling in my lab has shown that the losses caused by the separation
region exceed the gain.

>Now combine that idea with the change in depth to speed up the flue gases,
>and you will have a series of donut-shaped chambers that get shallower
>either towards the outside (or the inside - it is not yet clear). They will
>create chambers where the heat can 'rest a while' to mix and then rush
>through the gap to transfer heat to the plate. If the first ones are small
>and shallow with a large clearance to the plate's underside, the hot gases
>will speed by, and then as they cool down, they will linger longer
>languishing around to dump their final heat upwards.

I don't quite understand this idea. Maybe you could draw it for me and I'll
think about it for a bit.

Regards
Mark

----------
Professor Mark Bryden
Department of Mechanical Engineering
Iowa State University
Ames, Iowa USA

From dadelcnu at hotmail.com Mon Apr 22 18:48:32 2002
From: dadelcnu at hotmail.com (First Last)
Date: Tue Aug 31 21:37:47 2004
Subject: Nut-hulled pellets for backup heat
Message-ID: <F151bC8wSA1XvpFVjCR00016399@hotmail.com>

I'm off grid with passive solar heat and PV for electricity. I want to burn
pellets for backup heat because of the recycled angle, but I live near
California's nut country and want to use pellets made from recycled nut
hulls.

Does anybody know of a nut hull pellet?

_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp.

--Boundary_(ID_zITSzAa7zKDExC5bexwAsA)--

From willing at mb.sympatico.ca Tue Apr 23 06:12:48 2002
From: willing at mb.sympatico.ca (Scott Willing)
Date: Tue Aug 31 21:37:47 2004
Subject: STOVES VIRUS WARNING Message "A funny website" carries a virus.
Message-ID: <3CC52FD3.16871.661D5@localhost>

The message "A funny website," just distributed via the stoves list,
carries a virus.

Delete it.

No, this is not a joke or a false alarm.

Scott Willing

From psanders at ilstu.edu Tue Apr 23 10:06:07 2002
From: psanders at ilstu.edu (Paul S. Anderson)
Date: Tue Aug 31 21:37:47 2004
Subject: Chimney info
Message-ID: <4.3.1.2.20020423135720.01be6ec0@mail.ilstu.edu>

Stovers,

My local newspaper carried the following short item is "Grab Bag" by L.M. Boyd:

"In William Shakespeare's day, houses didn't have chimneys. Fires, yes.
Chimneys, no. Or if any did, they were most exceptional."

Certainly the "chimney innovation" has not reached all of the impoverished
homes in the world. It makes you wonder if a Shell Foundation grant for
"Household energy and health" could be put together just about chimneys.

But then again, the "burners" on modern stoves (not counting ovens with
flues to vent the gasses) do not require chimneys. Therefore, it seems to
follow that clean burning of fuels (defined as the levels similar to
operating a modern LPG - gas stove-top??) is all that is necessary to
eliminate the need for chimneys.

Could some "Stovers" please comment about operation of their various models
of stoves indoors, outdoors, with chimney, without chimney.

Concerning the Juntos gasifier stove, we have not tackled that chimney
question yet. But we desire sufficiently clean combustion that it competes
with modern stoves and modern (processed) fuels.

Just some thoughts, about which others might want to add some comments.

Paul

From tombreed at attbi.com Tue Apr 23 11:12:25 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:47 2004
Subject: Chimney info
In-Reply-To: <4.3.1.2.20020423135720.01be6ec0@mail.ilstu.edu>
Message-ID: <007501c1eb00$f459d5a0$4bc0fd0c@TOMBREED>

Dear Paul and All:

Excellent question.

Our position at the BEF Stoveworks is that a simple hood (not necessarily a
chimney) will carry out both the emissions of the stove (small or large) AND
the cooking odors, oil mists (from deep fry) garlic etc. Every Indian
teepee or Anisasi Kiva had a "smoke hole". So every African hut should be
instructed in supplying one. Could be a very simple, cheap piece of sheet
metal near the eves....

I hope that Elizabeth Bates from Boiling Point will wish to put on some of
her nice African hood pictures for all of us to admire...

Yours truly, Tom Reed BEF
STOVEWORKS
----- Original Message -----
From: "Paul S. Anderson" <psanders@ilstu.edu>
To: "Bob and Karla Weldon" <bobkarlaweldon@cs.com>; "Ed Francis"
<cfranc@ilstu.edu>; "Tsamba--Alberto Julio" <ajtsamba@zebra.uem.mz>; "Lily
Coyle" <astrozen2000@hotmail.com>; <stoves@crest.org>
Sent: Tuesday, April 23, 2002 1:13 PM
Subject: Chimney info

> Stovers,
>
> My local newspaper carried the following short item is "Grab Bag" by L.M.
Boyd:
>
> "In William Shakespeare's day, houses didn't have chimneys. Fires, yes.
> Chimneys, no. Or if any did, they were most exceptional."
>
> Certainly the "chimney innovation" has not reached all of the impoverished
> homes in the world. It makes you wonder if a Shell Foundation grant for
> "Household energy and health" could be put together just about chimneys.
>
> But then again, the "burners" on modern stoves (not counting ovens with
> flues to vent the gasses) do not require chimneys. Therefore, it seems to
> follow that clean burning of fuels (defined as the levels similar to
> operating a modern LPG - gas stove-top??) is all that is necessary to
> eliminate the need for chimneys.
>
> Could some "Stovers" please comment about operation of their various
models
> of stoves indoors, outdoors, with chimney, without chimney.
>
> Concerning the Juntos gasifier stove, we have not tackled that chimney
> question yet. But we desire sufficiently clean combustion that it
competes
> with modern stoves and modern (processed) fuels.
>
> Just some thoughts, about which others might want to add some comments.
>
> 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
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200204/
> http://crest.org/discussiongroups/resources/stoves/
> >
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
> >
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
> >
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
> >
> For information about CHAMBERS STOVES
>
>http://www.repp.org/discussiongroups/resources/stoves/Chambers/Chambers.htm
>

From szemay at doctor.com Tue Apr 23 17:13:32 2002
From: szemay at doctor.com (szemay)
Date: Tue Aug 31 21:37:47 2004
Subject: A IE 6.0 patch
Message-ID: <0GV100K2QV7BR2@ipop2.tm.net.my>

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From tombreed at attbi.com Wed Apr 24 05:11:06 2002
From: tombreed at attbi.com (Tom Reed)
Date: Tue Aug 31 21:37:48 2004
Subject: Fw: smoke hoods
Message-ID: <000701c1eb97$a03fa840$4bc0fd0c@TOMBREED>

Dear Stovers:

This message came from Liz Bates at BOILING POINT. Check her site for
pictures of installed hoods that reduce IAP levels by 75%!

TOM REED

----- Original Message -----
From: "Liz Bates" <lizb@itdg.org.uk>
To: <tombreed@attbi.com>
Sent: Wednesday, April 24, 2002 2:17 AM
Subject: smoke hoods

> Hi Tom
> The project to which you refer is just coming to an end, and I've already
> put together an article for Boiling Point. As I'm on the 'stoves digest' I
> cannot comment directly. However, our studies in Kenya have found that in
> both the Maasai community in Kajiado, and in rural West Kenya (though this
> is a very small sample size), the smoke hoods have reduced the levels of
IAP
> by about 75%. I'll certainly put in a photo of the smoke hood in the
> article, but if anyone would like to read the final report of the project,
> it is on the ITDG website (currently in the 'What's new' section), short
and
> long version. The long version, complete with pix is a huge file - over
5MB,
> but the pix-free version is manageable, and gives numbers. I can also send
> people a short 4-page precis of the project if they would like. If you
want
> to pass this message around, or mention that people can get Boiling Point
if
> they let me have their mailing address, please feel welcome.
> Very best wishes
> Liz
>
>
> > Liz Bates
> > lizb@ITDG.org.uk
> > Intermediate Technology Development Group
> > Schumacher Centre for Technology Development
> > Bourton Hall
> > Bourton On Dunsmore
> > Warwickshire
> > CV23 9QZ
> > Tel: +44 - 01926 634400
> > Fax: +44 - 01926 634401
> > www.itdg.org
> >
> > Company Reg. No 871954, England
> > Charity No 247257
> >
> >
> >
> >
> >
> >
> >
> This email and any files transmitted with it are confidential and intended
> solely for the use of the individuals or entity to whom they are
addressed.
> ITDG and it subsidiaries(ITC and ITDG Publishing) cannot accept liability
or
> contractual inferences for statements which are clearly the senders own
and
> not made on behalf of ITDG or it subsidiaries(ITC and ITDG Publishing).

From das at eagle-access.net Wed Apr 24 10:10:45 2002
From: das at eagle-access.net (Das)
Date: Tue Aug 31 21:37:48 2004
Subject: STOVES VIRUS WARNING Message "A funny website" carries a virus.
Message-ID: <200204241911.g3OJB3p04919@saturn.eagle-access.net>

how did this virus get distributed to ;the stoves list?

A. Das
Original Sources/Biomass Energy Foundation
Box 7137, Boulder, CO 80306
das@eagle-access.net

----------
> From: Scott Willing <willing@mb.sympatico.ca>
> To: stoves@crest.org
> Subject: STOVES VIRUS WARNING Message "A funny website" carries a virus.
> Date: Tuesday, April 23, 2002 8:56 AM
>
> The message "A funny website," just distributed via the stoves list,
> carries a virus.
>
> Delete it.
>
> No, this is not a joke or a false alarm.
>
> Scott Willing
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200204/
> http://crest.org/discussiongroups/resources/stoves/
> >
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
> >
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
> >
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon
> >
> For information about CHAMBERS STOVES
>
>http://www.repp.org/discussiongroups/resources/stoves/Chambers/Chambers.htm

From willing at mb.sympatico.ca Wed Apr 24 10:42:51 2002
From: willing at mb.sympatico.ca (Scott Willing)
Date: Tue Aug 31 21:37:48 2004
Subject: STOVES VIRUS WARNING Message "A funny website" carries a virus.
In-Reply-To: <200204241911.g3OJB3p04919@saturn.eagle-access.net>
Message-ID: <3CC6C44F.14599.120BB12@localhost>

I have no idea, but typically viruses of this replicate themselves by
mailing a copy out to everyone in an infected person's address book. I
would guess that someone picked up the virus and the stoves list was
one of their stored addresses. When you get your copy, it looks
indistinguishable from a message sent by the owner of the machine,
who may well be someone you know.

Many such viruses exploit the "features" of Microsoft Outlook to spread.

But regardless of what you use for an email client, effective defence
requires a good virus checker, *constantly updated and properly
configured,* with constant vigilance (especially, being highly suspicious
of ANY attachment) and, in some cases, disabling convenience
features of your email client in favor of increased security.

-=s

On 24 Apr 2002 at 12:34, Das wrote:

> how did this virus get distributed to ;the stoves list?
>
> A. Das
> Original Sources/Biomass Energy Foundation
> Box 7137, Boulder, CO 80306
> das@eagle-access.net
>
> ----------
> > From: Scott Willing <willing@mb.sympatico.ca>
> > To: stoves@crest.org
> > Subject: STOVES VIRUS WARNING Message "A funny website" carries a
> > virus. Date: Tuesday, April 23, 2002 8:56 AM
> >
> > The message "A funny website," just distributed via the stoves list,
> > carries a virus.
> >
> > Delete it.
> >
> > No, this is not a joke or a false alarm.
> >
> > Scott Willing
> >
> > -
> > Stoves List Archives and Website:
> > http://www.crest.org/discussion/stoves/200204/
> > http://crest.org/discussiongroups/resources/stoves/
> > >
> > Stoves List Moderators:
> > Ron Larson, ronallarson@qwest.net
> > Elsen L. Karstad, elk@wananchi.com www.chardust.com
> > >
> > List-Post: <mailto:stoves@crest.org>
> > List-Help: <mailto:stoves-help@crest.org>
> > List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> > List-Subscribe: <mailto:stoves-subscribe@crest.org>
> > >
> > Sponsor the Stoves List: http://www.crest.org/discuss3.html
> > -
> > Other Biomass Stoves Events and Information:
> > http://www.bioenergy2002.org
> > http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> > http://www.crest.org/articles/static/1/1011975339_7.html
> > Gasification
> > http://www.crest.org/articles/static/1/1011975672_7.html Carbon
> > >
> > For information about CHAMBERS STOVES
> >
> >http://www.repp.org/discussiongroups/resources/stoves/Chambers/Chambe
> >rs.htm
>
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/200204/
> http://crest.org/discussiongroups/resources/stoves/
> >
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
> >
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
> >
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
> http://www.crest.org/articles/static/1/1011975339_7.html Gasification
> http://www.crest.org/articles/static/1/1011975672_7.html Carbon > For
> information about CHAMBERS STOVES
> >http://www.repp.org/discussiongroups/resources/stoves/Chambers/Chambe
> rs.htm
>

From pverhaart at optusnet.com.au Wed Apr 24 21:09:05 2002
From: pverhaart at optusnet.com.au (Peter Verhaart)
Date: Tue Aug 31 21:37:48 2004
Subject: Fwd: Re: Chimney info
Message-ID: <5.1.0.14.2.20020425160323.00a601b0@mail.optusnet.com.au>

As usual I forgot to CC this to the Stoves List.
I also forgot to mention that Larry Winiarsky's Rocket Stove could very
likely, for the same reason, be used indoors without a chimney.
Piet
>Date: Wed, 24 Apr 2002 21:03:37 +1000
>To: "Paul S. Anderson" <psanders@ilstu.edu>
>From: Peter Verhaart <pverhaart@optusnet.com.au>
>Subject: Re: Chimney info
>
>At 14:13 23/04/02 -0500, you wrote:
>>Stovers,
>>
>>My local newspaper carried the following short item is "Grab Bag" by L.M.
>>Boyd:
>>
>>"In William Shakespeare's day, houses didn't have chimneys. Fires, yes.
>>Chimneys, no. Or if any did, they were most exceptional."
>>
>>Certainly the "chimney innovation" has not reached all of the
>>impoverished homes in the world. It makes you wonder if a Shell
>>Foundation grant for "Household energy and health" could be put together
>>just about chimneys.
>>
>>But then again, the "burners" on modern stoves (not counting ovens with
>>flues to vent the gasses) do not require chimneys. Therefore, it seems
>>to follow that clean burning of fuels (defined as the levels similar to
>>operating a modern LPG - gas stove-top??) is all that is necessary to
>>eliminate the need for chimneys.
>
>Yes. Complete burning of wood, as took place in the Downdraft stove, does
>not need a chimney to dump noxious gases outside the kitchen. The CO/CO2
>ratio we measured in Eindhoven was significantly below that for kerosene
>burners used indoors.
>
>Peter Verhaart

From Gavin at roseplac.worldonline.co.uk Thu Apr 25 07:54:04 2002
From: Gavin at roseplac.worldonline.co.uk (Gavin Gulliver-Goodall)
Date: Tue Aug 31 21:37:48 2004
Subject: STOVES VIRUS WARNING
In-Reply-To: <200204241911.g3OJB3p04919@saturn.eagle-access.net>
Message-ID: <MABBJLGAAFJBOBCKKPMGMEBPCFAA.Gavin@roseplac.worldonline.co.uk>

I did not get an attachment or a virus warning from my up to date checker
So did the list filter the nasty bits?

Gavin
-----Original Message-----
From: Das [mailto:das@eagle-access.net]
Sent: Wednesday, April 24, 2002 19:35
To: stoves@crest.org
Subject: Re: STOVES VIRUS WARNING Message "A funny website" carries a virus.

how did this virus get distributed to ;the stoves list?

A. Das
Original Sources/Biomass Energy Foundation
Box 7137, Boulder, CO 80306
das@eagle-access.net

From postmaster at crest.org Thu Apr 25 17:11:24 2002
From: postmaster at crest.org (postmaster)
Date: Tue Aug 31 21:37:48 2004
Subject: Undeliverable mail--"action "
Message-ID: <0GV500DDEKNWZU@ipop2.tm.net.my>

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From dstill at epud.net Sat Apr 27 20:43:38 2002
From: dstill at epud.net (Dean Still)
Date: Tue Aug 31 21:37:48 2004
Subject: Fw: Uganda Stove Pictures
Message-ID: <005101c1ee0c$5d6fa2a0$381d66ce@default>

>Dear Friends,

Sending some very small pictures of a fun project.
>
>Emma in Uganda and I have been designing a submerged pot Rocket type stove
>for the last couple of weeks following her testing of Lorena stoves.
>Exposing the sides as well as the bottom of the pot(s) to heat does wonders
>for fuel efficiency. As does using insulative materials between the pot and
>stove body. In this case, Ken Goyer made insulative fire bricks that left
>the appropriate small gap around the pots. The combustion chamber, also
made
>from his recipe, is a 12" high cylinder, 5" ID, placed under the first,
>larger pot.
>
>I tested the prototype today using one pound of wood. The 6.6 pounds of
>water in the first pot (12" diameter) boiled in ten minutes. Figuring
>8,600BTU/pound of wood 40% of the heat either heated water or turned it to
>steam.
>
>We've had a great week of sunny, windy weather here in Oregon and it's been
>very pleasurable to build this stove with Ken and Peter Scott, who is
>heading to South Africa soon to build similiar type stoves.
>
>Best,
>
>Dean
>
>
>

-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/200204/
http://crest.org/discussiongroups/resources/stoves/
>
Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>
>
Sponsor the Stoves List: http://www.crest.org/discuss3.html
-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://www.crest.org/articles/static/1/1010424940_7.html Bioenergy
http://www.crest.org/articles/static/1/1011975339_7.html Gasification
http://www.crest.org/articles/static/1/1011975672_7.html Carbon
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From elk at wananchi.com Sun Apr 28 16:18:37 2002
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:37:48 2004
Subject: How are you
Message-ID: <0GVB004EA27IU9@ipop4.tm.net.my>

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From ronallarson at qwest.net Sun Apr 28 17:47:44 2002
From: ronallarson at qwest.net (Ron Larson)
Date: Tue Aug 31 21:37:48 2004
Subject: bad news - maybe a virus
Message-ID: <00ac01c1ef26$c249d9a0$eeee6541@ronallarson>

Elsen

Almost for sure you sent a virus
to the web (stoves). I will try to determine what it was - I opened as it
had your name on. Better do a scan. We all got a relatively smutty
picture. (very few bytes) Also a Txt message, that said 0
bytes.

If you can determine from other
replies what it was, it would help us all get rid of it.

Right at the same time, I got another from
"webmaster" - and I didn't go quite so far in trying to open it - but my guess
is it also could have come from your computer. This one only (?) went to
me - not to the stoves list. Anyone else get that one?

Ron

From thomas.stubbing at heat-win.co.uk Sun Apr 28 20:51:09 2002
From: thomas.stubbing at heat-win.co.uk (Thomas Stubbing)
Date: Tue Aug 31 21:37:48 2004
Subject: bad news - maybe a virus
In-Reply-To: <00ac01c1ef26$c249d9a0$eeee6541@ronallarson>
Message-ID: <3CCCDEB5.C5122478@heat-win.co.uk>

Dear Ron et al,
Re. your message, another came this morning which, after its virus-infected
attachment had been deleted, simply read:
"Subject:         How are you
Date:        Mon, 29
Apr 2002 09:16:32 +0800 (SGT)
From:        elk <elk@wananchi.com>
To:       stoves@crest.org"
There was no text, and my Norton AntiVirus 2002 reported that the virus
in the attachment it had deleted was "W32.Kles.gen@mm".
I hope this helps.
Regards,
Thomas J Stubbing

Ron Larson wrote:

Elsen
Almost for sure you sent a virus to the web (stoves). I will try
to determine what it was - I opened as it had your name on. Better
do a scan. We all got a relatively smutty picture. (very few
bytes) Also a Txt message, that said 0 bytes.
If you can determine from other replies what it was, it would help us all
get rid of it. Right
at the same time, I got another from "webmaster" - and I didn't go quite
so far in trying to open it - but my guess is it also could have come from
your computer. This one only (?) went to me - not to the stoves list.
Anyone else get that one? Ron

From elk at wananchi.com Sun Apr 28 23:09:34 2002
From: elk at wananchi.com (elk)
Date: Tue Aug 31 21:37:48 2004
Subject: Virus info & removal tool
Message-ID: <00b501c1ef55$7cc61720$6e44083e@default>

This is most embarrassing! Sorry about that. I had
my Norton Antivirus program set for updating on a 14-day interval, and this new
virus has obviously slipped through my defenses.

Here is the info on the virus & links to the
Microsoft site that allows you to remove it.

elk

Again, my humble apologies for any
inconvenience.

--------------------------Elsen L.
Karstadelk@wananchi.com<A
href="http://www.chardust.com">www.chardust.comNairobi
Kenya

We would like to bring it to your attention that there is a NEW virus
currently spreading. The following is the description of the
virus.Name:
W32/Klez-GAliases:        <A
href="mailto:Win32.Klez.I@mm">Win32.Klez.I@mmType:
Internet and Network Worm, written in Visual C
language.Size:
84.6KbRisk:
MediumDESCRIPTION:W32/Klez-G is a slight modification of
Worm/Klez-A is an Internet worm capable of spreading through the local
network under Windows32-bit systems and infected EXE Files. In order to be
able to remain as a resident virus in the workspace, it infects the file
KERNEL32.DLL.Like other variations, the worm arrives through e-mail in
the following format:Subject Lines include (but not limited
too):- Fw: A nice game- Re: A WinXP patch- Re: Good removal
tools- Fw: A humour website- how are you- For more information,
please visitBody Text (examples):- This is a nice gameThis
is my first work.Your're the first player.I would expect you would enjoy
it- Hello,This is a humour gameThis game is my first work.You're
the first player.I expect you would like it.Attachment
(examples):- kitty.exe- rock.exe- play.scrIt uses an
exploit (a security hole) that allows the attachment to be executed when
viewing the message with Microsoft OutlookExpress or Outlook (without
Service Packs installed). This method is similar to the one used by Nimda or
Kak worms.Microsoft has issued a patch which protects users against this
vulnerability. It can be downloaded by visiting <A
href="http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-020.asp">http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-020.aspREMOVAL
TOOL:Microsoft has issued a patch which protects users against this
vulnerability. It can be downloaded by clicking here.<A
href="http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-020.asp">http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/bulletin/MS01-020.asp

From d.rl at virgin.net Mon Apr 29 00:00:07 2002
From: d.rl at virgin.net (David Reynolds-Lacey)
Date: Tue Aug 31 21:37:48 2004
Subject: VIRUS PROTECTION UPDATE
Message-ID: <3CCD0B7B.53141ACD@virgin.net>

Stovers,

This current virus attack is very worrying and I
would most respectfully suggest that it is every
poster's responsibility to the group to have
up-to-date virus protection which is updated EVERY
DAY, this automated procedure is easy to initiate
in all anti virus programs, most of which default
to 14 days which is just far too long to risk. A
new virus (often several) appear/s just about
every day, many only exploit the "holes" in
Microsoft's products, which I am pleased and
relieved to say I don't use.

One to watch for at the moment uses the .com
extension rather than .exe. When someone in their
"wisdom" decided on the .com extension for domain
names, they failed to take into account that the
same extension is used for compiled, executable
files, therefore beware of these files
masquerading as links, if you click on them they
will execute. I never, ever click on links with
.com extensions, I simply cut and paste them to my
browser location window from where executable
files cannot be run.

I am not sure how the "list" is scanned for virus
attack perhaps someone could let me (us) know the
procedure followed.

Many thanks

David

From crispin at newdawn.sz Mon Apr 29 00:48:44 2002
From: crispin at newdawn.sz (Crispin)
Date: Tue Aug 31 21:37:48 2004
Subject: Site for update to OE 5.01 or 5.5
Message-ID: <008801c1ef62$9207c220$71e80fc4@home>

I found it at

http://www.microsoft.com/windows/ie/downloads/critical/q290108/default.asp

Select the correct Service pack (there are only 2). It is 523K.

Regards
Crispin

From crispin at newdawn.sz Tue Apr 30 22:08:40 2002
From: crispin at newdawn.sz (Crispin)
Date: Tue Aug 31 21:37:48 2004
Subject: Info on the Klez.H worm that Eld did _not_ send out
Message-ID: <001b01c1f0df$cc4f3200$2a47fea9@md>

Dear Stovers

Sorry for the length of this but things are getting worse, it appears.

Elk has checked his machine and it is clean. The worm is apparently able to
pick up other email addresses and substitute them to make it appear as the
sender. The effect of this is to make it more difficult to track down the
infected machine and warn the real sender early. It is called address
spoofing. The name has also changed at least once to Kles.gen and it
appears people are stitching together parts of other worms. You can read
the little braggart's 'copyright' claim at the bottom of this message.

I received another copy this morning with an attachment of 170k which is the
largest version I have seen. I sent it in for checking (without
opening/reading it! - just drag and drop to the outgoing message) and
received the following reply. Please note how many additional file names
are appearing on people's drives.

In a bizarre twist, the one that arrived this morning gave as its 'sender' a
unique word taken from the filename of one of the files on our New Dawn
Engineering website. I am investigating the source of that message.

I have been communicating with the My eTrust systems engineer and they have
modified their cleaning approach to include the disabled versions of the
worm which I discovered hiding inside the .rar files. There were 9 on one
of my machines. It is in update v2004. Also see below.

Here in the 'bush' people are struggling to get their systems back up and
running. This is due to the expense (in our currencies) of antivirus
programs and professional help and the inconvenience and cost of getting
regularly downoaded updates.

Regards
Crispin

----- Original Message -----
From: Glen Iris EZ AV-Support <EZ_AVSupport@ca.com>
To: <crispin@newdawn.sz>
Sent: Wednesday, May 01, 2002 8:01 AM
Subject: myetrust technical issue : ref No.20020501153351614

****PLEASE NOTE: Further queries on this issue may be answered by a
different technician.****
****It is therefore very important that you include the full history of this
issue when replying so that we can provide an informed answer to your query
quickly.****

Thank you for your e-mail.

The file you sent us contained Win32.Klez.H which is detected and cleaned by
update 1993 or higher which is available for download from our website.

You should scan all files on your harddisk with EZ AV and then restart your
computer.

To scan all files go to:
[snip]

The worm spreads through open shares. If your hard drives are shared either
remove the share or password protect the share.

You should also download and install all Microsoft critical updates for your
computer. To ensure your Windows operating system has all critical updates
from Microsoft installed you can go to: http://windowsupdate.microsoft.com
and click on Product Updates

The following information is available at:

http://www3.ca.com/Virus/Virus.asp?ID=11779

Win32.Klez.H is a mass mailing network aware worm that spreads by using SMTP
and taking advantage of open network shares. In addition it drops a
polymorphic file infector virus into the Program Files directory.

The body of the message may be constructed from a list of phrases inside the
virus. Each message contains HTML code which exploits the "Incorrect MIME
Header" vulnerability in Internet Explorer Outlook and Outlook Express. If
successful the e-mail attachment will be opened on viewing the message
without the users knowledge.

For more information on this vulnerability see:

http://www.microsoft.com/technet/security/bulletin/ms01-020.asp

The attachment names vary as they are randomly generated. The extension is
randomly chosen from the following list:
.exe
.scr
.pif
.bat

Klez.H uses a variety of Subject lines that can include the following words
and phrases:

how are you
lets be friends
darling
so cool a flashenjoy it
your password
honey
some questions
please try again
welcome to my hometown
the Garden of Eden
introduction on ADSL
meeting notice
questionnaire
congratulations
sos!
japanese girl VS playboy
lookmy beautiful girl friend
eager to see you
spice girls vocal concert
japanese lass sexy pictures
Detected
Hi
Hello
Re:
Fw:
Undeliverable mail--"*****"
Returned mail-"*****"
a ***** ***** game
a ***** ***** tool
a ***** ***** website
a ***** ***** patch
***** removal tools

The Subject line may also include the name of the recipient.

The message body can be randomly constructed or in some cases left empty.
The following is a sample list that contains words and phrases that may be
used to construct the message body. The worm may also use the words and
phrases listed above for Subject construction:

The following mail cant be sent to *****:
The attachment
The file
is the original mail
give you the *****
is a ***** dangerous virus that *****
can infect on Win98/Me/2000/XP.
spread through email.
very
special
http://
www.
.com
For more informationplease visit
This is
This game is my first work.
Youre the first player.
I ***** you would ***** it.
enjoy
like
wish
hope
expect
Happy
Have a
Christmas
New year
Saint Valentines Day
Allhallowmas
April Fools Day
Lady Day
Assumption
Candlemas
All SoulsDay
Epiphany

where ***** is a word randomly selected from the following list:

new
funny
nice
humour
excite
good
powful
WinXP
IE 6.0
W32.Elkern
W32.Klez.E
Symantec
Mcafee
F-Secure
Sophos
Trendmicro
Kaspersky

Klez.H may use address spoofing to make the e-mail it sends appear as if it
has come from another machine. It uses addresses that it locates in the
infected system to display in the "From" line of the e-mail.

The worm can also send a message with the Subject:

"Worm Klez.E immunity"

and the message body:

[Beginning of message]
"Klez.E is the most common world-wide spreading worm.Its very dangerous by
corrupting your files. Because of its very smart stealth and anti-anti-virus
technicmost common AV software cant detect or clean it. We developed this
free immunity tool to defeat the malicious virus. You only need to run this
tool onceand then Klez will never come into your PC.

NOTE: Because this tool acts as a fake Klez to fool the real wormsome AV
monitor maybe cry when you run it.
If soIgnore the warningand select continue. If you have any questionplease
mail to me."
[End of message]

When the attachment is executed the worm drops a copy of itself into the
System directory. It then sets up a registry key to run itself on Windows
startup:

HKLM\Software\Microsoft\Windows\CurrentVersion\Run\="C:\WINDOWS\SYSTEM\"

The file name and registry value name are identical and are randomly
generated but always begin with "Wink". For example "Winkhj.exe".

The worm creates further copies of itself by inserting its code into .rar
archives. Note: On machines where Klez.H has [been] activated, CA antivirus
solutions report these files as infected; users need to manually delete
infected files located inside archives.

Klez.H also drops and activates a polymorphic virus - Win32/Wqk.C.

The encrypted text inside the worm code reads:

" & Win32 Foroux V1.0
Copyright 2002made in Asia
About Klez V2.01:
1Main mission is to release the new baby PE virusWin32 Foroux
2No significant change.No bug fixed.No any payload.
About Win32 Foroux (plz keep the namethanx)
1Full compatible Win32 PE virus on Win9X/2K/NT/XP
2With very interesting feature.Check it!
3No any payload.No any optimization
4Not bug freebecause of a hurry work.No more than three weeks from having
such idea to accomplishing coding and testing"

Klez also acts as a companion virus. It locates a Win32 PE program copies it
under a different name (using a random extension) and overwrites the
original with the worm code (e.g. - it copies MSACCESS.EXE to MSACCESS.UYI
and overwrites the original MSACCESS.EXE).

During this action the virus does not increase the size of the infected
program and keeps its original resources so it presents a user with the same
icon.

The copy of the original file is marked as system and hidden. It is also
compressed. As such the file is no longer a Win32 executable.
When a user executes a file that has been overwritten with the worm code -
for example - MSACCESS.EXE the worm runs first then it locates decompresses
and executes the original program.

Regards,

Steve Trusler
Systems Engineer
My eTrust Antivirus Support Team
Computer Associates

**** IMPORTANT INFORMATION ****
It is very important to update your antivirus product often to detect new
viruses written every day.

The Virus Update is updated almost every day and is available from
http://my-etrust.com/products/subscriptions/AntiVirus/

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