A biomass gasifier is a device that converts biomass (wood blocks, wood chips, rice husk, saw dust, and other such agricultural residues) into a combustible gas called "producer gas". The producer gas has a lower calorific value than CNG/LPG, but still can be used in oven/furnaces where the temperature requirement is up to 900 °C.

The gas generated from the gasifier is called "producer gas". The main combustible components of the producer gas are Carbon monoxide (20-25% v/v), Hydrogen (8-10% v/v), Methane(2-4% v/v) and small quantities of other higher gaseous hydrocarbons besides other non-combustibles like Carbon dioxide (8-10% v/v) and nitrogen (50-55% v/v). The typical calorific value of this gas is 1200 kcal/m3, which much less than LPG/CNG. Typically flame temperatures of over 1000 oC can be achieved by this gas.

The gasifier is a thermal reactor which thermally cracks the biomass into a gaseous state by the application of intense heat in a controlled oxygen starved atmosphere. The biomass is fed at the top of the reactor and moves downwards towards the grate by gravity. During this motion, it passes through the "drying", "pyrolysis", "controlled combustion" and "reduction" zones in that order. The boundaries of each of the zone above are not rigid but transitional. Moreover, depending on the wood characteristics and the load, the height of each zone also varies. Each of the zones, have a specific reaction component to perform, resulting in the formation of "producer gas" and ash/char mixture at the end of the reduction zone, where the grate is located.

Applications with temperature requirement up to 900 oC can use producer gas / gasifier without any problems and any change in the existing system. With air preheating, the temperature requirement up to 1100 oC can be met.

No, Gasifiers have a very high thermal inertia, which ensure a very stable gas production.

No, the wood/biomass takes over 2 hours to get fully converted to producer gas. Hence, small variations in fuel quality/characteristics get averaged out, and a fairly uniform quality of gas is produced.