Biomass fuel gasification furnace

The invention provides a biomass fuel gasifier which comprises a cylindrical gasifier body, a feeding device and an air extractor, a combustion chamber, a gas purification chamber and a tar processor are arranged in the gasifier body, the tar processor is arranged in the gas purification chamber and comprises a top ash outlet formed in the upper end of the tar processor, and the top ash outlet extends out of the gasifier body towards the top of the gasifier body. And a sealing cover capable of being opened and closed is arranged on the top ash outlet. The top ash outlet is formed in the tar processor, a pipeline of the tar processor is soaked, cleaned or brushed, cleaning convenience of the tar processor is improved, the risk of being blocked is reduced, the tar processor is arranged in the gas purification chamber, damage to the tar processor is reduced, and the tar processor can be used for gas purification. The service life is prolonged; the gasification effect on tar in smoke is improved; according to the