Circulating fluidized bed gasifying system and gasifying method thereof

Abstract

The invention discloses a circulating fluidized bed gasifying system and a gasifying method thereof. The circulating fluidized bed gasifying system comprises a fuel breaking and feeding system, a fluidized bed gasifying system, a residue discharging system, a synthetic gas waste heat recycling system, a flyash removal circulatory conveying and utilization system, a crude gas purifying and distributing system and the like. The whole waste heat recycling system and flyash reutilization system are used herein, gasifying sensible heat of synthetic gas is completely used to produce saturated steam and superheated steam, a circulating remelting gasifying scheme and a boiler combustion scheme may be used for flyash, energy utilization efficiency is maximized, water resource consumption is minimized, and the circulating fluidized bed gasifying system is applicable to fuel gas preparation systems for the industries such as ceramics, industrial kilns, glass kilns and steel making, and has a promising application prospect for use as coal-derived fuel gas station mainstream techniques.

Description

technical field [0001] The invention relates to a circulating fluidized bed gasification system and a gasification method thereof, belonging to the technical field of coal gasification. Background technique [0002] There are abundant reserves of low-rank coal such as lignite in the world. At present, my country's low-rank coal resources such as lignite account for about 55% of the country's proven coal reserves, and more than 80% of the coal stock in Southeast Asia is lignite. In addition, Australia, Africa and other places also have abundant reserves low-rank coals such as lignite. Low-rank coals such as lignite have the remarkable characteristics of low heat, high water, and high volatile matter, and some lignites are also accompanied by low ash and high sulfur characteristics. At present, lignite is mainly used for power generation through fluidized bed boilers and pulverized coal furnaces, among which fluidized bed boilers are more commonly used, and a small amount of c...

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Problems solved by technology

[0006] 3. The calorific value of the output syngas is high, and the system efficiency is low;

[0009] 1. The bed height fluctuates greatly in the pressurized fluidized bed gasifier, and the carbon conversion rate is low;

[0010] 2. After fluidized bed gasification, the product entrains a large amount of particulate matter, and the service life of waste heat recovery equipment is short;

[0011] 3. Fluidized bed gasification mostly adopts the recycling method, and the design of high-efficiency cyclone separator is difficult;

[0012] 4. Fluidized bed gasification and slagging design is unique, the operating conditions are harsh, and the reliability is low;

[0014] 6. After fluidized bed gasification, the content of residual carbon in fly ash is relatively high, the particle size is relatively small, and post-processing is difficult

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