Process for preparing fuel gas through graded pyrolysis and gasification of powdered coal

Abstract

A process for preparing fuel gas through gasification of powdered coal, comprising: contacting powdered coal and ash residue in a riser reactor under hydrogenation conditions to perform a pyrolysis reaction and a gas-phase tar cracking reaction; subjecting it to a primary gas-solid separation to obtain a gasified gas and a solid fraction; subjecting the gasified gas to a secondary gas-solid separation to obtain a solid fraction containing fine particle semi-coke and a gasified gas; subjecting the solid fraction to a gasification calcination reaction, flowing the gasified coal gas and the high-temperature ash residue u into the riser reactor; subjecting the solid fraction containing fine particle semi-coke to a melting gasification reaction, falling the liquid residue to the material-returning device of fluidized bed for cooling and solidification, and feeding the second high-temperature gasified coal gas to the riser reactor via a high-temperature gasified gas returning pipe.