Bio-char Correspondence, A

Hi D -

I've heard your name a billion times because many Zambians tend to think all Americans know one another; however I am familiar with your work with XXXXXX/ XX XXXX and have eaten your peanut butter and breakfast cereal very often. My name is Carl Wahl and I work for Concern Worldwide in Western Province heading up the Conservation Agriculture projects in Mongu, Kaoma, and Senanga (plus many new districts we're not sure of yet). 

I would love to hear more about your bio-mass / charcoal project. Are you trying to do distributed or centralized production? We (NGI, CeLIM, and myself) are working on various ways to make cheap and clean sources of charcoal; NGI and I are more interested in bio-char as a soil amendment because of our incredibly sandy soils; CeLim through Caritas and the Mongu Diocese are looking for ways to make sustainable charcoal. 

Currently, I'm been banging around with a TLUD system using a very slightly modified 55 gallon drum. Great if you have a uniform product of sufficient size to ensure airflow (e.g. bamboo or pigeon pea stems), but I think you'd need some forced air and a good draft for things like rice husks / sawdust. The big thing with smaller diameter feedstock is that it's hard to get good combustion of the gases driven of by the pyrolysis ... without that, you get a very smoky (and GHG-wise a very dirty) burn. 

Another thing I'm likely going to pilot at Kasisi in the next month or two is a double-drum system, e.g. a smaller diameter drum filled with feedstock upside-down inside a 55-gallon drum; in the airspace between the drums, you pack in a dry fuelsource that "bakes" the feedstock in the inner drum, eventually flaring off the volatiles in a relatively clean process. However, you need to gather additional biomass to get the process going. 

One thing we have identified for sure with the CeLim folks: making briquettes from bimass feedstock using an extruder and then making the charcoal hasn't worked very well, as the charring process weakens the briquettes and makes a lighter density, cold-burning (relatively) product. We'd like to figure out a way to make the char first, crush the char, mix with an adherent (e.g., shredded and boiled cassava), and then extrude.

Blah-blah-blah. Would enjoy meeting up with you sometime and chatting about what worked in XXXXXXX province as we did some of the same stuff in Senanga. 

Best,

Carl