Kudos to the Warm Heart team for developing a series of trough-shaped Flame Carbonizers designed to work with a diverse array of feedstocks available to small farmers in Thailand and elsewhere. These kilns are similar to the pyramid shaped kilns except they are elongated into troughs in order to accommodate long stalks, branches and stems without the need for cutting. They are brilliant for bamboo!
Warm Heart has done a wonderful job of not only matching kiln design to feedstock, but also of creating and documenting the stoking techniques needed for efficient production with diverse feedstocks, especially light weight materials like rice straw that can ash very quickly if not properly fed to the kiln.
Warm Heart has also provided dimensions and welding details for constructing the kilns. That warms my Open Source heart!
Some pictures below, but make sure you visit the Warm Heart site for all the details: http://warmheartworldwide.org/new-type-fc-biochar-production-unit/
The Warm Heart Trough Flame Carbonizer
Stoking corn stalks
Stoking rice straw using the "drag method"
Wet blanket quenching method - very innovative!
Stoking bamboo in a longer, narrower kiln
Quenching bamboo biochar