[Stoves] [biochar] Capturing carbon in the timber industry

[Tom Miles]

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

 

 

 

From: stoves-bounces at lists.bioenergylists.org [mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Crispin Pemberton-Pigott
Sent: Monday, December 20, 2010 3:30 AM
To: 'Discussion of biomass cooking stoves'
Subject: Re: [Stoves] [biochar] Capturing carbon in the timber industry

 

Dear Tom

 

Is there perhaps valuable oil in the bark not found in the wood?

 

The $150 is just below the street price of charcoal in Maputo so it is high. One certainly could not bury that much money.

 

Do you happen to know the charring temperature for (predominantly) oil in the output?

 

Thanks

Crispin

 

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