Gasifier Stoves

Introduction – the Gasifier Principle

Micro-gasifiers cookstoves are small gasifier devices that create their own gas from solid biomass and are small enough to fit directly under a cook-pot. Gasifiers can separate gas generation from gas combustion in space and time. In a reactor (gas generator) that is optimized for heat-dependent drying and pyrolysis, solid biomass is first converted into gases and vapors. These are guided into a combustion zone (gas burner) where they are burnt with a surplus of oxygen from a secondary air inlet. The following infographic shows this principle.

In a conventional fire the heat is controlled by regulating the fuel supply: the more fuel we add, the more heat we generate, provided sufficient air is available for the combustion. In contrast to this, gasifiers control and optimize both processes separately to achieve efficient and clean utilization of the fuel:

regulating the heat that is reaching the solid biomass to optimize the drying and pyrolysis process
controlling the supply of air and regulating the availability of oxygen for optimizing the subsequent steps of wood gas combustion and char gasification. More air to the ‘gas-generator’ produces more gas that can be combusted in the ‘gas-burner’. The regulation, however, is a bit tricky and one of the challenges is to find a better solution to this.

Gasifier stoves are currently the cleanest burning option to burn solid biomass in a cook stove. The “gas burner” provides the convenience and efficiency similar to cooking on fossil gas with very little soot and other emissions.[1]

For more information on the process of wood gas generation see also Cooking with Woodgas.