Circulating fluidized bed coal gasification method and device with fine powder ash fusion

Abstract

A circulating fluidized bed coal gasification method with fine powder ash fusion comprises the following steps that (a), coal (B) and a gasifying agent (A) are delivered into a circulating fluidized bed coal gasification furnace (1) to be subjected to a gasification reaction, and coal gas (C) and gasified fine powder ash (D) are generated; (b), the coal gas (C) and the gasified fine powder ash (D) are separated; (c), the separated gasified fine powder ash (D) is collected; (d), the gasified fine powder ash (D) obtained in the step (c) is delivered into a smelting furnace (3); (e), carbon-contained high temperature gas (H) rich in CO and CO2 and high temperature liquid slag (P) are generated; and (f), the carbon-contained high temperature gas (H) is delivered back into a gasification furnace hearth of the circulating fluidized bed coal gasification furnace (1) or a refeed valve, and the high temperature liquid slag (P) is discharged out of the smelting furnace (3). The invention further provides a circulating fluidized bed coal gasification device with the fine powder ash fusion. The circulating fluidized bed coal gasification device and method with the fine powder ash fusion are high in gasification efficiency and carbon conversion efficiency.

Description

technical field [0001] The invention belongs to the technical field of coal gasification, and relates to a coal gasification method and device, in particular to a circulating fluidized bed coal gasification method with fine powder ash melting and a device using the method. Background technique [0002] Classified according to the movement state of solid fuel, modern coal gasification processes mainly include moving bed (also known as fixed bed) gasification, entrained bed gasification and fluidized bed gasification. [0003] The moving bed coal gasification process mainly uses lump coal as raw material, and its main advantages include: low-quality coal can be used for gasification; high pressure gasification production capacity; low oxygen consumption, which is the lowest oxygen consumption among the three types of coal gasification methods The method; the operating temperature of the reaction furnace and the outlet gas temperature are low, the carbon efficiency is high, and...

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Problems solved by technology

[0008] It is an effective way to improve the carbon conversion rate of the system by sending the fine powder ash generated by the reaction in the traditional fluidized bed or circulating fluidized bed coal gasifier into the high temperature reactor for secondary reaction, but there are three major problems: first, the existing The return of heat after carbon conversion in fine powder ash technology is mainly used to supplement the heat in the lower part of the gasifier, while the upper part of the gasifier furnace is a severe gasification reduction zone, which requires a lot of heat to improve the gasification reaction efficiency. For circulating fluidization bed coal gasifier, heat supplement from the lower part of the gasifier cannot fundamentally solve the problem of gasification heat supplement; secondly, the gasification fine powder ash produced by circulating fluidized bed coal gasification has high carbon content and a large amount. Proper disposal will cause dust pollution; finally, the fine powder ash of circulating fluidized bed coal gasification is mainly semi-coke with low volatile content, no water, and poor reactivity. To achieve high-temperature gasification or combustion of fine powder ash, ensure Liquid slag discharge is a major technical difficulty, and the existing technology does not provide a feasible solution

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