Wood Gas

Wood Gas is composed of H2 and Carbon Monoxide. Both of these gases are flammable hence its' usability as fuel. It can be produced from wood, as the name implies. A "Gasifier", the device that makes Wood Gas, heats wood in an near airless environment. The wood goes through pyrolysis which creates tars(in the gas phase) and wood gas.

Down Draft Stratified Wood Gasifier

Terms

• Stratified: Its called stratified because of the different layers of wood in different states of decomposition.
• Down Draft: The gasifier uses a down draft that originates at the wood hopper opening. This downdraft flows through the inactive wood layer down to the pyrolysis layer where it feeds the heat reaction, but isn't enough to actually burn the wood. As the air enter the pyrolysis layer it pushes the newly released wood gas and tars down the fire tube, through the ash chamber and filter unit, and into the engine/storage unit.

Components

• Wood hopper: metal cylinder (I used a galvanized trash can) holds inactive wood, wood going through pyrolysis, and ash and charcoal which falls down the fire tube.
• Fire Tube: A metal cylinder(mine is about 6 inch in diameter) attached to a flat metal circle. Needs to be slightly smaller then the hopper so it can fit just inside the mouth. The fire tube connection to the hopper must be air tight(it would be best to Braze it).
• Ash Chamber: Metal cylinder about the same size as the hopper. Ash and charcoal dust falls through the grate into this component, and they must be removed on a regular basis. The wood hopper(with fire-tube) is brazed to the ash chamber to make it air tight. A hatch needs to be added to allow for ash/charcoal dust removal. The gas flows from the fire-tube through the ash chamber and on to the filter unit.
• Filter Unit: 5 gallon metal bucket filled with wood chips. The filter unit catches ash and charcoal dust that is light enough to flow with the wood gas.