Comprehensive utilization method and system for bottom slag quenching treatment of circulating fluidized bed boiler

Abstract

The invention discloses a comprehensive utilization method and system for bottom slag quenching treatment of a circulating fluidized bed boiler. The comprehensive utilization system is mainly composedof a quenching slag cooler, a heat exchanger, a bottom slag treatment device and a condensation heat exchanger. The comprehensive utilization method and system aim to solve the problems that a CFB boiler unit is large in slag discharge amount, low in sulfur slag utilization rate, large in limestone usage amount, too high in slag discharge temperature and the like. According to the comprehensive utilization method and system, furnace slag generated by a hearth is directly subjected to contact quenching treatment. The generated quenching bottom slag is firstly dried by tail fume and then is subjected to component analysis in a bottom slag component separation treatment device, and the bottom slag with high free CaO content is used as a desulfurizing agent and is sent back to the boiler again; the bottom slag with low content of free CaO and CaSO4 is used as cement admixture; and the bottom slag with high CaSO4 content is used as a cement adjusting retarder. The generated high-temperature steam and the dried fume are subjected to heat exchange with feed water and then enter a coal economizer as "economizer feed water". According to the comprehensive utilization method and system, residual heat of the slag is fully utilized, boiler fuel is saved, thermal pollution is reduced, and the thermal efficiency of the boiler is further improved.

Description

technical field [0001] The invention belongs to the field of circulating fluidized bed bottom slag treatment, and in particular relates to a comprehensive utilization method and system for rapid cooling treatment of circulating fluidized bed boiler bottom slag. Background technique [0002] With the widespread application of large circulating fluidized bed boilers (CFB) boilers. In the process of its practical application, the existing problems are becoming more and more prominent, seriously hindering its development and application. According to incomplete statistics, at present, the total discharge of desulfurization ash in my country is more than 30 million tons per year, and the discharge of desulfurization ash produced by CFB boiler power plants is increasing year by year. However, CFB boilers mostly use low-quality coal and high-sulfur coal, and the ash and sulfur content in coal are relatively high. Therefore, a large amount of limestone needs to be added for desulf...

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Problems solved by technology

Aiming at the low utilization rate of desulfurization ash and slag in the operation of CFB boiler units in my country, the large amount of limestone used, and the high failure rate of boiler overheating and slag coolers, a new method for comprehensive utilization of ash and slag in CFB boiler units is proposed to solve the problem of CFB desulfurization The problem of low ash utilization rate

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