Process for preparing synthesis gas by gasifying raw materials with different coal quality characteristics by adopting oxygen-enriched circulating fluidized bed

Abstract

The invention discloses an oxygen-enriched gasification process for a circulating fluidized bed gasifier, which comprises the following steps: introducing a mixed gas, namely a gasifying agent, formed by mixing oxygen, water vapor and carbon dioxide or air into the fluidized bed gasifier; raw material coal is added into a gasification furnace and is subjected to gasification reaction with a gasification agent; crude synthesis gas containing carbon monoxide and hydrogen generated in the reaction and gasified fly ash are introduced into a cyclone separator together, most of the fly ash settles to enter the bottom of the cyclone separator and returns to the gasifier to be gasified again, and a small amount of the fly ash and the crude synthesis gas enter the next treatment section. According to the oxygen-enriched gasification method of the circulating fluidized bed, the temperature in the gasification furnace can be effectively controlled, and the problem that the bottom of the gasification furnace is prone to slagging due to local overheating is solved. In addition, due to the fact that all the components of the gasifying agent are gas capable of participating in the gasification reaction, controllable components of the coal gasification product crude synthesis gas can be achieved by regulating and controlling the proportion of all the components of the gasifying agent, and the gasifying agents with different component proportions can be matched according to feed coal with different coal quality characteristics.

Description

technical field [0001] The invention relates to the technical field of coal gasification, in particular to a process for producing synthesis gas from coal gasification of raw materials with different characteristics of coal by adopting an oxygen-enriched circulating fluidized bed. Background technique [0002] In the process of coal gasification, due to the uneven operating temperature, a large amount of VOCs and tar substances will inevitably be produced in the lower temperature area, resulting in low effective gas production and complex composition, which is not conducive to the normal operation of subsequent separation or purification processes. In addition, coal with high alkali and low ash melting point is prone to excessive heating temperature at the bottom of the fluidized bed gasifier, resulting in serious slagging and adverse effects on operation. At the same time, for raw coal with different coal quality characteristics, it is necessary to replace and deploy differ...

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Problems solved by technology

[0003] The invention aims to adopt the oxygen-enriched gasification process of the circulating fluidized bed to reduce or avoid the formation of VOCs and tar substances in the crude synthesis gas at the outlet

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