Welshboy, List
There is a steep learning curve in using woodgas as a fuel. Gasifiers produce a mix of carbon monoxide and hydrogen. Do not even consider running one indoors.
Whilst in principle it is a matter of heating suitable chunks of wood in a reduced oxygen atmosphere, there is a lot more to it than that.
Gasifiers are notoriously difficult to keep running well and require a lot of tinkering and attention to keep them running constantly.
The fuel has to be the right moisture content and the right size and shape for it to fall correctly into the gasifying zone and produce gas efficiently. Every so often you have to rattle the grate to help the fuel fall.
Wood gas has a calorific value about 1/6th that of natural gas and needs to be mixed almost exactly 1:1 with air to burn efficiently and so jets and burners would have to be changed accordingly. This makes the idea of converting a domestic boiler less overall attractive.
There are however gasifying stoves appearing on the market. These heat the wood in an upper chamber and the wood gas is drawn through to another chamber to be burned with the correct quantity of preheated air. These stoves are considerably more efficient than the traditional cast iron stove.
Just this weekend I saw these photos of someone who had converted his furnace (US) to be a gasifying stove.
http://lakeweb.net/gasifier/Gasifier_Furnace.htmlThe wood is placed in the upper chamber and the woodgas is burned below - see pictures. It looks like he has cast the "nozzle" from fireclay or other refactory ceramic and is burning the gas in a "box" made from storage heater bricks - the idea being that these will soak up the heat and release it slowly.
Might I suggest that you join a group such as
WoodGas@yahoogroups.com where you will find a lot of fellow gasification enthusiasts.
YouTube now has many videos of home made gasifiers - none of them look particularly tame!
Ken
