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Would be very interested in results. My understanding is that the problem with charcoal is that it never gets hot enough (a) to burn out all of the tars and other aromatics and (b) to form the carbons into the necessary sheets of ring structures. If this is not true, why are we so excited about biochar when the alternative of using charcoal is so close at hand?
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Dr. D. Michael Shafer
Founder and Director, Warm Heart
Michael, cc Kevin
It should be fairly easy to test with seed sprouting at a kitchen window.
I view all char as pretty much the same (if. The interior reaches the same temperatures. The reason is that all combustion is two-stage. The first stage is char-mkaing - followed by a second stage where the char is combusted. In the first stage, gases exiting through the outer layer of char prevents oxygen to get to the char itself. After all the internal gases are released (as the interior comes up to a final temperature) - then the oxygen can finally hit the hot outer layer of char.
Michael thinks that because the char from three stone is not made without oxygen, it will not work as biochar. What do you think?
No. Some soils will be wrong of course. I think the temperature range produced by most TLUDs is like 3 stone fires and TLUDs have some good reports (thinking of Bangladesh)
I’m almost finished with.a drawing of new idea for replacing multiple stones below the wood supply. Can use your existing tripod potholders. Might add 70-80%. A skirt seems worthwhile and cheap here also.
Do you know of any reason that embers pulled from three stone would not make good biochar? Maybe not perfect biochar but good biochar? Someone from SNV suggested they would not make good biochar but I don't think this SNV person is an expert on biochar.
Here is the SNV embers report
. It is very encouraging. Pulling embers out of the fire resulted in a negligible increase in fuel usage. The weight of the char exceeded the weight of the additional wood.
The problems (cook time, tending, smoke) referenced by SNV are not problems that have been expressed by the women in Africa. We are exploring.
We are already training farmers to crush the char, mix with urine and ashes and apply to their fields. This is at a small scale now but can be expanded easily.
I see great potential for this, especially where farmland is degraded, like most of SS Africa. I'm talking with SNV about more testing.
We are shifting to metal tongs (35x2 cm). They are simple to make, use very little metal (140 sq cm), are cheap ($0.15 - 0.20) and durable.
We are seeing promise in this. Tongs are made from bamboo, very cheap and easy. Women pull the embers out as they cook. Here is a photo. A video is attached.
<Pile of char from tongs - Kasese.jpeg>
This woman collected 400g in a day. She did not notice any change in fuel usage or smoke.
SNV Vietnam is going to do a water boil test to determine whether there is a change in fuel usage. It seems like it should require more wood.
Kevin McLean, President