Prepyrolysis type fluidized bed biomass gasification device

The utility model aims to provide the pre-pyrolysis type fluidized bed biomass gasification device, firstly, biomass raw materials with larger size difference can be pretreated in the fixed bed pyrolyzer, and the biomass raw materials are stirred, preheated and preliminarily pyrolyzed through the heating and gasification effects of the refluxed high-temperature synthesis gas, so that the biomass raw materials are fully gasified, and the biomass raw materials are fully gasified; the biomass raw material enters the fluidized bed gasifier in a smaller and more uniform state, the operation stability in the fluidized bed gasifier is improved, and meanwhile, part of high-temperature synthesis gas flows back into the fixed bed pyrolyzer, so that the biomass raw material is preheated, and the energy consumption is reduced. And the part of synthesis gas enters the fluidized bed gasifier again through the sealed spiral feeder to participate in the carbon gasification reaction, so that the concentration and the heat val