Circulating fluidized bed and pyrolysis bed combined gasification process and device

Abstract

The invention provides a circulating fluidized bed and pyrolysis bed combined gasification process and device, and relates to a coal gasification technology. The gasification process is characterized in that a fluidized bed technology is used for pyrolysis and gasification, and coal free of tar and other pollutants is converted into gas; semicoke coal and the like are gasified and burnt out by a pyrolysis bed; coal-containing fly ash is removed from the gas with a precipitation separation method and is returned to fluidized bed gasifier by a screw conveyor to be pyrolyzed and gasified circularly. The fluidized bed gasifier, a cyclone separator, the pyrolysis bed and a sedimentation chamber which are connected are used for combustion and transport of raw coal, the gas, the semi-coke and the coal-containing fly ash, and accordingly, the purpose of the invention is achieved. The gasification process and device have the beneficial effects that the gasification rate of the raw coal is high, and tar and other pollutants are not produced; the circulating fluidized bed is applicable to equipment with large, medium and small gasification rates, and regulation range of gas production capacity in unit time is broad.

Description

technical field [0001] The invention relates to a coal-to-gas compound gasification device, specifically a gasification furnace for sequential fluidized pyrolysis gasification of a circulating fluidized bed and a pyrolysis bed, which is used for the gasification of raw coal and belongs to the technology of coal gasification equipment field. Background technique [0002] With the rapid development of industrial economy, coal combustion has become an indispensable way to obtain heat in the process of industrial production. However, direct burning of coal will cause great pollution to the environment, so the state has issued a large number of documents about prohibiting direct burning of coal for heating in recent years. Instead, raw coal is converted into clean and pollution-free gas for combustion to obtain heat. For this reason, various gasifiers for converting raw coal into gas have been designed, such as fixed-bed gasifiers, circulating fluidized-bed gasifiers, etc. Form...

AI Technical Summary

Problems solved by technology

However, after studying the existing various forms of gasifiers, it is found that each gasifier has its own advantages and disadvantages. For example, the fixed bed gasifier has high coal conversion rate and thermal efficiency, and the coal gas contains a large amount of tar and other pollutants; Circulating fluidized bed gasifier produces clean gas without tar and other pollutants. However, the thermal efficiency of raw coal is low, and the coal slag contains a large amount of semi-coke. It is necessary to transport the coke-containing coal slag to a low-demand combustion environment for re-combustion , such as thermal feedstock for combustion in thermal power plants

On the one hand, it reduces the utilization rate of coal, on the other hand, it increases the transportation labor and other costs

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