Circulating fluidized bed boiler and desulfurization method

Abstract

The invention provides a circulating fluidized bed boiler and a desulfurization method. The circulating fluidized bed boiler comprises an in-furnace desulfurization system and an out-furnace desulfurization system which are communicated in sequence, wherein the in-furnace desulfurization system comprises a hearth; the hearth is provided with a first inlet, the circulating fluidized bed boiler further comprises a limestone conveying pipeline and a quicklime conveying pipeline, and the limestone conveying pipeline and the quicklime conveying pipeline are communicated with the first inlet. In thewhole process of starting the circulating fluidized bed boiler, when the boiler does not reach the optimal temperature range of the limestone reaction, quicklime (calcium oxide) as a desulfurizing agent is first directly adopted for directly reacting with sulfur dioxide in flue gas in the hearth for desulfurization reaction; when the optimal reaction temperature range of the in-furnace limestonedesulfurization system reaches in the boiler, an out-furnace circulating fluidized bed ash circulation system is established, limestone is fed into by the limestone conveying pipeline for desulfurization of sulfur-containing flue gas, high calcium oxide content in the hearth can be kept all the time so as to achieve the efficient desulfurization effect in the furnace.

Description

technical field [0001] The invention relates to the technical field of circulating fluidized bed boilers, in particular to a circulating fluidized bed boiler and a desulfurization method. Background technique [0002] Circulating fluidized bed boilers are the best way to utilize low-quality coal and coal washing waste on a large scale, and can achieve emission standards of sulfur dioxide and nitrogen oxides at a low cost. At present, circulating fluidized bed boiler technology has developed to supercritical steam parameters of 350MW and above, and 17 supercritical circulating fluidized bed units have been put into operation so far, which has played a positive role in improving the level of manufacturing equipment in my country. [0003] With the increasingly serious environmental protection situation in China, coupled with the sharp decline in the utilization hours of coal-fired power generation units, the units start and stop frequently, and it is difficult to control the s...

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Problems solved by technology

[0005] The main purpose of the present invention is to provide a circulating fluidized bed boiler and a desulfurization method to solve the problem of poor desulfurization effect of circulating fluidized bed boilers in the prior art

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