Michael Cox wrote:Hi Folks,
The cone kilns which were first appearing two or three years ago looked promising....
Post 1/22/2017 2:13:22 PM Subject: Biochar making - various kiln designs
"[...] I have used open fires "
Bryant RedHawk wrote:I don't have a photo but I will give the description of one of the simplest "oven" designs that I've tried and found to work quite well for biochar production.
Use a steel 55 gal. drum with a retaining ring held in place lid, this is your oven (they last long enough to off set the small cost of buying a used one every time one wears out).
take a 2 foot piece of steel pipe (or anything that is usually used as a flue pipe, even the ones used for venting hot water heaters work well) set it in the center of the lid and mark around it so you can see the line.
remove the pipe and use a 1/4" drill bit to make a dozen or so holes in the lid inside the pipe's line you just made.
next is fastening the section of pipe you used to make your circle mark to the lid of the drum. (I used tin snips to make 8 tabs, remove the "waste" and then I drilled and pop riveted the vent pipe to the lid)
Use 4 8x16 inch concrete blocks spaced around the bottom rim so the drum will sit up off the ground (set these so the drum sits on the center reinforcement of the blocks)
Take the barrel off the positioned blocks and dig out the soil in the center so you have a pit for building a fire.
To use this for making charcoal or biochar you just fill the drum with your wood, packing it in as tightly as possible.(this is easiest to do if the drum is laying on its side, then stood up on top of the blocks and more sticks pushed in to really pack the drum)
stand the drum on the concrete blocks after laying the wood for the fire, place the lid on and use the clamp ring to fasten the lid to the drum.
Light the fire under the drum, keep the fire as hot as you can make it, once the wood heats up use a long match or stick to ignite the fumes that will be coming out of the "stack".
This is a pretty simple TLUD type of setup and it works.