神华神东山西河曲发电有限公司(河曲CFB电厂)超临界350 MW机组循环流化床(CFB)锅炉超低排放技术路线为炉内高效脱硫抑氮+选择性非催化还原(SNCR)脱硝技术+炉外烟气循环流化床法脱硫工艺.通过现场试验,验证了床层温度、运行氧量和炉内钙硫摩尔比等运行参数对炉膛出口NOx、SO2排放的影响规律,以及向CFB锅炉内加入石灰石和设置前置电除尘器对脱硫脱硝运行经济性的影响.结果表明:可通过试验调整运行参数,控制炉外脱硫塔入口SO2质量浓度,综合比较锅炉热效率、炉内喷钙系统石灰石消耗量、脱硝系统尿素消耗量和炉后脱硫系统Ca(OH)2消耗量,选取最佳运行参数,实现燃烧效率和炉内脱硫、脱硝系统运行经济性最优;炉外脱硫系统前设置前置电除尘器,经济性更佳.该结论为采用烟气循环流化床法脱硫工艺的新建机组和实施超低排放改造的大型CFB锅炉提供了参考.%For the supercritical 350 MW unit circulating fluidized bed (CFB) boiler in Shenhua Shendong Shanxi Hequ Power Generation plant (Hequ CFB plant), the ultra low emission technological route is efficient desulfurization and nitrogen suppression in the furnace, selective non-catalytic reduction (SNCR) denitration and CFB flue gas desulfurization system outside the furnace. By means of site test, the influence of parameters such as bed temperature, oxygen concentration and mole ratio of calcium to sulfur inside the furnace on emission characteristics of NOx and SO2 was verified, and the effects of adding limestone into the furnace and setting pre-electrostatic dust precipitator on economy of desulfurization and denitration were also discussed. The results indicate that, the SO2 concentration at entrance of the CFB flue gas desulfurization system outside the furnace can be controlled by adjusting the operation parameters. The optimal operation parameters were chosen after carefully comparing the boiler efficiency, limestone consumption inside and outside the furnace and urea consumption in the denitration system, then the optimum combustion efficiency and economy of desulfurization and denitration were achieved. Setting the pre-electrostatic dust precipitator at inlet of the CFB flue gas desulfurization system increased the unit economy. The research can provide references for the newly built and retrofitted large-scale CFB units with CFB flue gas desulfurization system.
展开▼
