{"id":407,"date":"2010-08-02T00:29:50","date_gmt":"2010-08-02T10:29:50","guid":{"rendered":"http:\/\/washedashore.com\/eggsntea\/?p=407"},"modified":"2010-08-02T00:29:50","modified_gmt":"2010-08-02T10:29:50","slug":"biochar-from-kiln-to-pit","status":"publish","type":"post","link":"http:\/\/ahualoa.net\/farmblog\/2010\/08\/biochar-from-kiln-to-pit\/","title":{"rendered":"Biochar: from kiln to pit"},"content":{"rendered":"

Those of you following the biochar-hawaii<\/a> list know that i’ve stopped using my kiln, and am now focused on making biochar in a pit. This is both for reasons of scalability and wear; my 55-gal steel drum kiln\/retort could only make ~23-gal of char, and the surrounding kiln blocks cracked from repeated heating.<\/p>\n

Hence, a pit. Mine is lined with blocks for clean char and easy unloading. Continuously fed wood, pyrolysis occurs at the air-starved bottom of the pile, gradually the pit fills up, then i cover and let it cool for a day, before opening and scooping out the finished char:<\/p>\n

\"\"<\/a> \"\"<\/a> \"\"<\/a> \"\"<\/a> \"\"<\/a><\/p>\n

That first small pit worked well, so i made it bigger and sure enough, it scales well:<\/p>\n\n\n\n\n\n\n\n
Width<\/td>\nLength<\/td>\nDepth<\/td>\nGallons<\/td>\nCubic feet<\/td>\n# of blocks<\/td>\nGallons of Char<\/td>\n<\/tr>\n
24<\/td>\n32<\/td>\n16<\/td>\n53.2<\/td>\n7.11<\/td>\n33<\/td>\n16.5<\/td>\n<\/tr>\n
32<\/td>\n48<\/td>\n16<\/td>\n106.4<\/td>\n14.22<\/td>\n48<\/td>\n34<\/td>\n<\/tr>\n
32<\/td>\n48<\/td>\n24<\/td>\n159.6<\/td>\n21.33<\/td>\n60<\/td>\n68<\/td>\n<\/tr>\n
32<\/td>\n48<\/td>\n24<\/td>\nOn second burn:<\/td>\n82<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

That 82-gallon operation took 2.5 hours to do the burn, then 2.25 hours the next day to unload, crush, sort, sift, and load into buckets. That’s 82\/4.75 = 17.25 gallons of char per hour of work. That’s not bad, given that i’m working with some cheap concrete blocks, a piece of old corrugated roofing, and a shovel. With more money and technology, like a continuous pyrolysis machine<\/a>, you could certainly get vastly more char per hour of labor, but those machines start at $100,000. I’m feeling quite happy about my pit. The Biochar2010 album<\/a> has all the pictures.<\/p>\n

I gave a biochar talk to the Kona Coffee Grower’s Association on June 2. 10 minutes of that talk<\/a> got uploaded to YouTube. I then addressed the Hawaii Tropical Fruit Growers on July 19, that time with a fancy presentation with charts and pictures. Next will probably be an evening talk in Waimea on August 8, and then a 1-day workshop on making and using biochar here at our farm, date TBA.<\/p>\n","protected":false},"excerpt":{"rendered":"

Those of you following the biochar-hawaii list know that i’ve stopped using my kiln, and am now focused on making biochar in a pit. This is both for reasons of scalability and wear; my 55-gal steel drum kiln\/retort could only make ~23-gal of char, and the surrounding kiln blocks cracked from repeated heating. Hence, a […]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[10],"tags":[],"class_list":["post-407","post","type-post","status-publish","format-standard","hentry","category-biochar"],"_links":{"self":[{"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/posts\/407","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/comments?post=407"}],"version-history":[{"count":2,"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/posts\/407\/revisions"}],"predecessor-version":[{"id":409,"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/posts\/407\/revisions\/409"}],"wp:attachment":[{"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/media?parent=407"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/categories?post=407"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/ahualoa.net\/farmblog\/wp-json\/wp\/v2\/tags?post=407"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}