This project goes over the build of a cross flow wood gasifier that powers a generator or a car or any kind of internal combustion engine using nothing more than wood scraps, paper, coal or any other organic materials. This unit was built in nothing more than an angle grinder, and a hand drill and parts that you can find lying around.
These devices are taking advantage of a process called gasification, in which you can take any kind of organic biomass, really anything natural that burns and by heating it up, you are able to break it down through a process called pyrolysis to its basic elements. This creates a gas called syngas or wood gas. Here we are burning biomass in an oxygen deprived environment. And that heat which is sustained through just enough oxygen to not spread to ignite the gases produced by the heat interacting with the surrounding material is the process that we are using to create wood gas.
The gases coming out contains things like water vapor from moisture content in the wood, also creates tar and creosote .So we need to filter out the gas. And the main concern of getting that gas to be clean enough to run an engine is by cooling it down. We connect the unfiltered gas coming from the pressure pot into a radiator to cool it down and then further connected to a bucket filled with saw dust to filter .
The reactor unit is made of an old 5 gallon painting pressure pot . The first step is to burn it out removing old residue and paint. Also burn out the inside container as well.
Make sure everything on the lid of the pressure pot is removed and sealed off with a plug or bolt. Remove the rubber gasket on the backside of the lid. The holes on surface of the lid are covered with three eighth inch bolts.
At the bottom of the pot , we attach two pipes for the the air intake and the syn gas suction output. These pipes are held tightly to the pot with the help of one and quarter inch pipe flanges.
The air comes up from the bottom, the gasification happens in the middle of this reactor and the ash gets sifted to the bottom through a passive shaker grate. The output pipe is capped at the top to prevent the residue ash going out and small holes are drilled along the pipe to allow the wood gas to pass through.
Next step is to build the grate insert where the fuel will actually sit on and burn on. The grate will sit about two and a half inches off the bottom of the pot. The grate is made from the other stainless steel container that came with the pressure spray painting pot.
Grid of holes are drilled along the surface of the grate using a quarter inch drill bit. The grate is finally is inserted into the reactor pot chamber .
The gasket on the back of the lid of the pot is removed and replaced with fiberglass rope that can withstand temperature up to 2000 degree Fahrenheit. The rope is secured in place using a gasketing cement and stove sealer. The lid is clamped in place until the gasket cement is dry.
The next step is to build the cooling and the filtering system. To get all the tar and steam to condense back into their liquid form , we use a old oil heater radiator that act as a condensate catcher . The gas coming out of the reactor is connected to the radiator which gets most of the heat out of them.
We build the filtration system using a 5 gallon metal bucket to get the gas as clean as possible. The output pipe is attached to the bottom of the bucket using a flange. The bucket is filled with a filter medium such as wood shavings or sawdust that will trap any sort of particulates and get more tar out of the gas.
An old car blower from a toyota is attached to the top of this bucket to get that gas up to the point where it can burn. The blower motor is supported with a old 10 tin can that is then secured at the center of top of the bucket .Another soup can is soldered to the 10 can on the side to attach the output hose pipe.
We don't want there to be enough oxygen to actually just burn all the material in there before we can extract the gases . So we are limiting this by using a one way gate valve . The one way valve is important to prevent flashbacks if too much oxygen is there inside the reactor .
We load the reactor with wood sticks and put some starter down in there, which is just some cloth, some paper and a sprinkle some wood pellets on top just to give us something small to start off with. We pack the reactor leaving a spot in the center . The fans is turned on and we start the ignition process.