Simple wood gasifier
Wood gasification is the process of turning wood into carbon monoxide and hydrogen by reacting the raw material (wood) at high temperatures with a controlled amount of oxygen. Without oxygen, the wood can't burn so it transforms into gas. This gas can be used as fuel in an internal combustion engine.
During World War II wood gas generators where used to fuel automobiles in Europe. I've been thinking about building one and seeing if I could run a small lawn mower engine off of wood gas.
For an experiment I built this small wood gasifier. My setup is not a full scale gasifier. It justs pyrolysizes the wood. A few more steps are needed for full gasification. The gas coming out of the can, has a high tar content. If used in an engine, it would eventually coat the cylinder with tar and cause it to seize up.
All I used was a quart paint can, propane stove and some plumbing fittings. I used the propane stove just to make things easy. In a regular gasifier, charcoal is used as the heat source. The plumbing fittings where used to carry the gas away from the can. They are not really needed, but I wanted to make sure I showed that the gas can be piped away. First I drilled a hole in the lid of the paint can. Then put a connector in the hole and J.B. welded the connector to make sure it had an air tight seal. I then added a few more pipe fittings just to show that the gas could be piped away. Last I made a burner out of a small tomato paste can.
I filled the paint can with dry wood and made sure the lid was on tight. A minute or two after I put the paint can on the stove, wood gas/smoke started to come out of the plumbing pipe. The wood gas easily ignited. It took a few more minutes before enough gas was being produced to sustain a flame.
The gas contains carbon monoxide which is both flammable and poisonous, so you need to make sure to do this outside and not breath in the gas. Because you have a paint can full of flammable gas, there is always the chance the can could blow up. Hopefully just the top would pop off with a loud boom, but I wouldn't put my head to near the can.
Here you can see the wood gas coming up through the plumbing.
All that is left of the wood is charcoal.
My next plans are to scale this up and use charcoal as the heat source. There are a ton of plans on the net. One of the best documents I found, was made by FEMA back in the 1980's. It describes how wood gasification works and how to build a would gasifier for use on a tractor.