NOTE: I am no longer supporting this design as I believe these retort styled systems are pressure explosions waiting to happen. If you are interested in producing biochar I would suggest you look at the commercially run TLUD based Bazman Rumbler or keep an eye out for the new ‘in development’ Bazman Bincharra.
Welcome to the GIBBR project (Gas Ignition Biochar Batch Reactor)
This is an open source style of project. Please read the warning at the bottom of this page. If you have any issue with this design or claim ownership, contact me directly by comment below.
Project overview: I wanted to develop a safe(ish) way to produce Biochar in a vessel around the size of a 44 gallon drum, it needed to be mobile so I could wheel it into place outside my shed, it needed to be able to produce enough Biochar for my 2000m2 permaculture food forest, I wanted a system which would not spark and produce any smoke because of our long dry seasons and fire bans, it needed to accept logs, branches and chunky feed stock. It was to use LPG gas for ignition. Feedstock has to have a low moisture content, fresh green waste is not suitable for this style of system as I have discovered.
Development of this system has come about from a lot of trial and error, cutting the system up and rebuilding, I’m always open to positive feedback and suggestions and I’m sure a lot of refinement will continue into the future. If your serious about developing a GIBBR style system feel free to message me.
Note: the photos in the plan are slightly different, the reaction chamber exhaust pipe should travel down next to the reaction chamber reducing wood smoke condensation.
The syn-gas produced by the system vents directly inside the powerburner flames, the reason for this is to vaporise all early stage smoke, as this early stage smoke can have quite a high moisture content and is not very flammable, once the exothermic reaction occurs the LPG gas burners can be shut down as the produced syn-gases are highly flammable and the system will fuel itself until finished. Try and stay upwind of the running system while watching it, this will reduce your exposure to any toxic gases produced.
This photo gives you a bit of an idea of what you are dealing with.
Please read this warning: This system runs super hot (650+ degrees Celsius), it produces extremely flammable gases, touching any metal part of the machine when running or for hours after operation will burn skin, all exhaust gases are toxic so operation outside is important. Blocking or jamming the exhaust pipe out of the reaction chamber will cause the system to possibility explode, killing or burning anyone near by. The reaction chamber should be at normal atmosphere with a slight increase in pressure when the system goes exothermic. Much care and respect needs to be taken around this system, children should never ever be allowed near the system when running. The ground around the system should be clear as grass will catch fire from radiant heat produced. Never put sealed containers inside the running reactor. Always wear thick leather gloves, safety glasses, with all skin and hair covered. Once the system has gone exothermic it is extremely difficult and dangerous to try and stop. You need to stay with the system during operation and access to a water hose to dampen the ground is important. I accept NO responsibility for any damage you or your system creates. This system is not suitable for small backyards sorry, try looking up ‘biochar gasifier stove’. Check with your council and maybe just let your local fire department know what you’re up too.