[Gasification] Chunking wood for small scale biochar production

David Coote dccoote at mira.net
Wed Jan 1 17:53:41 CST 2014

An inexpensive tool to chunk efficiently wood for small scale biochar 
production would be very handy. I have loads of waste woody biomass on 
my farm. There's no community scale biomass energy plants in the 
northern hemisphere sense in Gippsland (SE corner of Australia) so no 
local markets of this nature for the material. This may change in the 
next few years but in the interim I'd like to make some char as a 
weekend project. One of my nephews is a qualified boiler maker with 
tickets for various specialist welding techniques. He's interested in 
building a small char system. This would probably be similar to the 
popular 44 gallon drum with internal retort (so an indirect 
implementation) but using a better quality steel so a bit longer 
lasting. And we'll lag the drum, put a safety enclosure around it and so on.

One of the challenges of trying to do this beyond a hobby approach is 
chunking the material to be used for  combustion and char. I haven't got 
time to lovingly handcarve the feedstock into the appropriate size and 
form. Using an axe, saw, firewood splitter, bypass pruners would all be 
possible for different sized feedstocks (windthrow, prunings, thinnings, 
harvest residue etc) albeit labour intensive.  Something like an old 
chaff cutter would be very useful for some feedstocks. I think there are 
some commercial chunkers that would do what I want but they are 
prohibitively expensive


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