Operation And Optimization Of Wind-water Combined Ash Coolers For 300MW Circulating Fluidized Bed Boiler Firing Gangue

With the energy crisis getting serious, the circulating fluidized bed combustion technology as a new generation of clean and efficient combustion technology has developed rapidly in China. The circulating fluidized bed boiler burn the the fuel which contains a high proportion of slag, and much more heat will be lost when the slag is discharged. Slag cooler can not only ensure the ash discharged smoothly but also can recycle waste heat of boiler slag, which can improve the thermal efficiency of the boiler unit. The operation condition of the slag cooler directly affects the safe and economic operation level of the whole unit.In this paper, the performance characteristics and research status of various types of slag cooler are analyzedat at home and abroad, including air-water combined slag cooler.drum type slag cooler and so on. Among them, air-water combined slag cooler is the earliest and most widely used in dry slag disposal system of circulating fluidized bed boiler in China. Although there are many problems in the operation of air-water combined slag cooler. But it has the advantages of good heat exchange effect, large amount of slag, low temperature of slag and so on. Therefore, to improve the operation reliability and economy of the slag cooler, which is of great significance to the energy saving and emission reduction of the unit.The research object of this paper is 200 MW air-water combined slag cooler of coal gangue circulating fluidized bed boiler which is from Shanxi Zhangdian Guodian Wangping Power Co., Ltd. Based on its structure and design parameters. The gas solid two phase flow in the cooling chamber was simulated by using FLUENT software. Finally, we can get the results that the air distribution, slag particle size, wall channel size and other parameters have influence on the slagging process. We also calculated and analyzed the effects of the amount of slag,the temperature of slag and slag moderate cooling water backwater location on boiler thermal efficiency and steam turbine economy.