The invention belongs to the field of
new energy, and particularly relates to a water-cooled grate
biomass gasifier and a
biomass gasification method. The water-cooled grate
biomass gasification furnace comprises a gasification furnace body of a downdraft structure, the gasification furnace body is internally provided with a feeding
system, the feeding
system comprises a feeding chute, a feeding sealing door and a feeding sealing door, the feeding chute is provided with an anaerobic
system pipeline, and a feeding grate is located below the feeding sealing door; the water-cooling fire grate
assembly is composed of multi-stage
welding type water-cooling fire grate segments, and a cooling water cavity is formed in the water-cooling fire grate
assembly. The
hearth is divided into a
drying layer, a
pyrolysis layer, a reduction layer and an oxidation layer in the material moving direction. The gasifying agent supply system comprises a primary air duct, a secondary air duct, a
steam injection pipeline I and a
water vapor injection pipeline II, wherein
pure oxygen is introduced into the primary air duct; the cooling circulation system comprises a circulation pipeline, a circulation water pump and a radiator, wherein the circulation water pump and the radiator are installed on the circulation pipeline. The circulation pipeline is communicated with the water-cooling fire grate
assembly to form a closed circulation loop. The device is high in reliability, long in service life, low in emission, easy to control and good in gasification effect.