Two-step method for gasification of pulverized coal fluidized bed and device utilizing method

Abstract

The invention relates to a two-step method for gasification of a pulverized coal fluidized bed and a device utilizing the method. The two-step method for gasification of the pulverized coal fluidized bed includes: the first step, gas generated from a gasification furnace is led into a dry distillation column and runs through a feed coal layer in the dry distillation column to heat, dry and distill feed coal, so that temperature of the feed coal raises and water content thereof is evaporated and separated, high-heating-value gas such as CH4, H2 and the like are decomposed from the feed coal, most carbon-bearing flyash carried by gas can be adsorbed and filtered by the feed coal layer when flowing through the feed coal layer, and accordingly gas can be purified; the second step, the feed coal is dehydrated, dried and distilled to be hot semi-coke, the hot semi-coke is fed into the gasification furnace to be gasified, carbon-bearing flyash enters the gasification furnace to be gasified along with the semi-coke, and accordingly carbon conversion efficiency is improved. By the two-step method, carbon-bearing flyash carried with gas can be filtered and fed into the gasification furnace to be gasified circularly during the gasification process of the fluidized bed utilized for any coal types, so that carbon conversion efficiency is increased greatly, heating value of gas is increased, utilization of sensible heat of gas is improved, and pollution of flyash to environments is decreased.

Description

[0001] technical field [0002] The invention relates to the technical field of coal gasification, in particular to a two-step pulverized coal fluidized bed gasification method and device. Background technique [0003] Fluidized bed gasification is a relatively advanced gasification technology between fixed bed and entrained flow bed. Its advantages are that it can use 0-10mm pulverized coal as gasification raw material. It has wide adaptability of coal types and low operating cost. , There is no tar in the gasification process, the gasification intensity is higher than that of fixed bed, and the investment is lower than that of entrained bed. The disadvantage is that the temperature of the gas at the outlet of the fluidized bed gasifier is very high, usually between 900 and 1050 °C, and it is not suitable to use bag dust removal, because a large amount of carbon-containing dust is entrained in the gas, and a high-temperature cyclone separator is usually used to separate...

AI Technical Summary

Problems solved by technology

For young coal such as lignite, the moisture content is very high, which seriously affects the gasification efficiency. Due to the poor thermal stability of lignite, it is easy to crack when heated, and the drying of lignite has always been a difficult technical problem to solve.

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