50 kilowatt wood pellet gasifier / charcoal maker (Sept
27, 2000)
Alex English english@kingston.net
What we have
here is a demonstration of gasification in one of its simplest, yet most
effect, forms. This is an old water heater fitted with an air distribution
manifold base and a partial premix burner on top.
The cylinder holds 100kg of wood pellets containing 1860 MJoules
of energy. The column of pellets is lit on top.
Air flow up through the pellets feeds the pyrolysis process, which
creeps down at a rate of aproximately 20cm per hour.
The tar rich gas is continuously burned with a stable orange flame.
7.5 hours later the flame turns to blue as the pyrolysis
front reaches the bottom and the volatile component of the fuel is
used up. At this point the cylinder can be sealed and the
20 kg of charcoal, containing about 560 MJoules of energy, are allow
to cool. The heat output for those seven hours was about 50kWatts. Fan
energy consumption is about 120 watts. A few modifications would eliminate
the need for any fans.
Green wood chips, bark waste and hay have also been tried with less
consistant results so far.
Charcoal by product
from dry wood pellets and dry hay.
