As a followup to my last biochar post, i was sent the following document from Karl Frogner of UBI. Karl asked me to make it available, so i’ve put it here: Biochar Ovens, until UBI has a place for it on their own site.
It describes experiments conducted in Mongolia on making biochar in a steel drum where the combustion occurs in a metal center tube. Innovative and fascinating! I want to try it here on my farm, but i’ll have to somehow locate some heavy large-diameter metal pipe, and be able to make holes in it.