Coal gasification method

Abstract

The invention provides a fluidized bed-entrained flow bed gas gasification method. The method comprises the following steps: 1) carrying out reaction on raw material coal and a mixture of air and steam or a mixture of oxygen and steam to obtain gas containing incompletely reacted coal and ash; 2) separating the gas obtained from the step 1) to obtain condensed fine coal air-flow and light fine coal air-flow, and carrying out reaction on the condensed fine coal air-flow with air or oxygen to obtain gas containing coal and ash; 3) carrying out reaction on the gas obtained from the step 2) and steam to obtain gas containing coal and ash; 4) carrying out reaction on the gas obtained from the step 3), the light fine coal air-flow separated from the step 2) and a mixture of steam and carbon dioxide to obtain final gas containing coal and ash. The method lowers investment and operating cost of a traditional pulverizing system by an entrained flow bed gasification method and has a substantially increased gasification temperature than a traditional fluidized bed gasification method, so as to reduce equipment cost and increase gasification efficiency.

Description

technical field [0001] The invention belongs to the field of coal gasification technology, and relates to a coal gasification method, in particular to a novel fluidized bed-entrained bed gasification coal gasification which combines fluidized bed gasification and entrained bed gasification to improve gasification efficiency and reduce costs method. Background technique [0002] Modern industrial coal gasification processes mainly include fixed bed gasification, fluidized bed gasification and entrained bed gasification. [0003] Fixed bed gasification must use lump coal (6 ~ 50mm). Coal and gasification agent flow countercurrently, cold coal enters and cold gas flows out, which is beneficial to reduce oxygen consumption in the gasification process and improve gasification efficiency. However, on the other hand, in order to prevent the ash sintering in the gasification process, the amount of steam used is relatively large, which causes a large consumption of sensible heat in...

AI Technical Summary

Problems solved by technology

However, the disadvantages of the conventional fluidized bed are: 1) to prevent slagging, the operating temperature is low (850 ° C ~ 950 ° C), so it is only suitable for lignite and high-activity bituminous coal; The amount is relatively high (up to about 10% of the coal amount), and another boiler must be installed for combustion

This process needs to control the reaction temperature of the second stage, which is easy to produce coal tar

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