Wood gasification is a process that converts organic or fossil fuel-based carbonaceous materials into carbon monoxide, hydrogen, and carbon dioxide. This is achieved by reacting the material at high temperatures (>700 °C), without combustion, with a controlled amount of oxygen and/or steam. The resulting gas mixture is called syngas or producer gas and is itself a fuel.

In simple terms, here are the basic steps of wood gasification:

Drying: As the wood is heated, the first process that occurs is drying. Moisture is removed from the wood at around 100°C.

Pyrolysis: This step happens around 200-300°C. The wood starts to break down chemically, and volatile components are vaporized, leaving behind charcoal. The volatile substances are a mixture of complex hydrocarbons, which are combustible.

Combustion: In the combustion zone, the volatile hydrocarbons, carbon dioxide, and water vapor from the previous step react with oxygen and burn. This burning process produces heat, carbon dioxide, and water vapor. The heat is used for the next step, gasification.

Gasification: This is the final step, which occurs at around 800-1000°C. Here, carbon in the charcoal reacts with steam and carbon dioxide to form carbon monoxide and hydrogen, also known as syngas.

The syngas produced can be used as a fuel in engines, for heating, or in the production of chemicals. Wood gasification is considered a form of renewable energy if the wood source is managed sustainably. It’s also a way of converting biomass waste into usable energy.