[Gasification] Charcoal Gasifiers

[Robert Kana]

Dear Tom,
Several years ago, I coupled 11 Adam retorts together. Each kiln was 
almost 4 m3 capacity. We load the kilns with sawdust wooden briquettes, 
2613 kg average and yield was 31.6 % good quality charcoal.  As you know 
we had 2 chimneys, one in the front where the burning wood and later 
burning woodgas come out, and the second one in the back connected to 
the wood chamber. Briquettes were very dry, it took about 12-18 hours to 
get the wood gas. Than back chimney was closed and wood gas was pushed 
in to fire chamber in front of the kiln. And it burned none stop for 
almost 48 hours. I started wondering, what can we do with this gas? 
Briquettes were high density and very dry about 6000 Kcal. per kg. The 
energy was burned equaled 18233 Kwh. I was amazed and started asking 
questions how to use this energy? The gas we burned was dirty. Than I 
find out about wood gas, gasifiers... After long research and with the 
help of many people from this forum, I build my first gasifier.
While in operation, I coupled all the back chimneys, put a long 
galvanize pipe 38 cm diameter, with 10 degrees slant. I distilled the 
smoke coming out of drying wood, every day we were getting wood vinegar 
400 liters and more. Unfortunately no one was interested, I even offered 
to local farmers associating free of charge, I gave samples to 
universities to some research, nobody was interested. Wood vinegar is 
highly used in Japan for vegetable gardens, flowers, in bathtub water as 
detoxification the body and clean the skin and so an...
The back chimney was filled with tar in no time. This was the tar at the 
beginning of coming out the wood gas.  Still was bad enough for us to 
clean the back chimney every month. The rest of the wood gas was burned 
in the chamber.
We tried to get the gas with out burning and move to the kiln where we 
dry the sawdust. The result was very good until the tar clogged the 
pipes in less than a week. Finally I gave up trying the gas was 
extremely dirty.
There are couple of problems taken gas from the kilns. One we can not 
suck the gas, than we would introduce extra oxygen to the kiln, that 
would effect the quality of the charcoal. Second if we use the small 
chimney to collect the gas and collect from there, we would taken extra 
air and mix with the wood gas, I think that would be dangerous..
Now we are working with 47 ovens, still every day I look at the wood gas 
that we burn, and still we are buying wood and rice husk to burn in my 
oven to dry the saw dust.
If anybody has an idea, how to collect this gas, I am willing to try.
Regards,
Robert
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