Solid fuel staged gasification-combustion dual-bed polygeneration system and method

A solid fuel staged gasification-combustion dual-bed polygeneration system comprises a combustion system, a gasification system, a synthesis gas cooling and purification system and a synthesis gas methanation system. The combustion system is associated with the gasification system by means of a circulating feedback system. The combustion system uses circulating fluidized bed combustion. The gasification system uses a fluidized bed incomplete gasification method. Semi-coke generated returns to the combustion system for reuse. The synthesis gas cooling and purification system uses a water circulation and combustible recycling method. CO 2 and water vapor produced in the synthesis gas methanation system as byproducts are recycled in the solid fuel staged gasification-combustion dual-bed polygeneration system, thereby maximizing the energy utilization efficiency in the system.