The gasification efficiency of a novel two-stage gasifier was studied and analyzed by numerical simulation.In this model the coal-water slurry(CWS)gasification process was divided into several sub-models:water droplet evaporation

coal pyrolysis

gas homogeneous reaction and gas-solid heterogeneous reaction.Turbulent flow mixing and chemical reaction were considered in the rate of gas phase reaction.The unreacted-core shrinking model was used to describe the rate of gas-solid heterogeneous reaction.The realizable k-ε turbulence model was used for the gas phase flow

and coal-water slurry particles were tracked by the Random-Trajectory model.The CWS gasification model was verified based on the model subject of a pilot-scale opposed multi-burner(OMB)gasifier.The simulation result showed that effective gas composition of the novel two-stage gasifier was 85.91%

and cold gas efficiency was 76.42%.