Thanks Tom
That was really informative. I have been testing a TLUD coal stove from Turkey (“Silver” is the producer). The air supply needed work but it was very clean for a long time when not operated in the suggested manner (just about the opposite actually). I have never seen so many zeros in a row. The CO/CO2 ratio fell below 0.00% (about 0.008%) for several hours burning wet lignite. Operated as suggested the excess air dropped to less than 1% which obviously is not so good. It will get a few adjustments I feel – they received very specific alteration suggestions. The problem is the same as with all the batch stoves: if it is refuelled in a ‘traditional’ manner, the smoke is far worse than the traditional stove. That means training people not to do what comes naturally (let the stove die out and refuel and relight from scratch. Big task. Regards Crispin +++ Subject: Re: [Stoves] [biochar] Capturing carbon in the timber industry Crispin, Lots of work was done on bark utilization by Jean Mater, Mater Engineering, from about 1945 on. Her work is in USFS publications. Jean died a couple of years ago. When the US National Renewable Energy Laboratory (NREL)was researching fast pyrolysis the principal contractor (Midwest Research) patented several chemicals from bark pyrolysis with major wood industries. They were mostly resins for use as industrial adhesives. I think Ensyn (Canada) also has a process to make adhesives from pyrolysis products. As far as I know these products are not in commercial use. I'm sure that the cost to make charcoal for Maputo is considerably lower than here. One challenge for Southern Africa is how to make the portable metal bush kilns more efficient and environmentally friendly while keeping the cost and capital low enough to benefit the population that is now making charcoal. How can you make kilns that are more attractive than earth kilns? It's hard to beat labor vs capital. Oil making pyrolyzers have substantial capital investments. 70% yield oil (15% char + 15% gas) requires an industrial plant (Dynamotive, Ensysn). Either the gas or char is consumed in the process. Slow pyrolysis yields about equal quantities of oil, char and gas. In both cases you are externally heating the wood at about 450C. For high oil yields the wood is finely divided and typically pyrolyzed using an externally heated sand carrier, as in a circulating fluidized bed. Manuel Garcia Perez, Washington State University, provided a nice overview of pyrolysis technologies in his November presentation at a Washington Future Energy Conference: http://www.futureenergyconference.com/2010/FECWA-Presentations/4D_Garcia.pdf Gasifiers yield 2-5% char and gas and tars. Reaction temperatures are about 800C for the char. The beauty of the TLUD is the gas yield for cooking and a higher yield of char. Tom
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