火电厂脱硫系统石膏脱水困难案例分析及对策

结合山西大土河焦化有限责任公司热电一分厂3×75 t/h循环流化床锅炉石灰-石膏湿法烟气脱硫工程实例,针对石膏脱水异常导致脱硫系统无法正常运行的问题,采用定性分析方法,根据浆液颜色其及沉降分离状况,以及浆液脱水滤饼外观,快速准确地判断出其主要原因为浆液中飞灰、CaSO₃·1/2H₂O和未溶解的氢氧化钙含量过高。采用降低飞灰含量,疏通氧化空气管路,投加石膏晶种和及时调整运行状态的方法,使问题得以解决。所采用的定性分析方法适用于脱硫工程中的应急处理。

Case Analysis and Solutions of Gypsum Dewatering for FGD Systems of Power Plants

Based on the case of the lime/gypsum wet flue gas desulfurization(WFGD) system for the 3×75 t/h circulating fluidized bed boiler in the cogeneration power plant of Shanxi Datuhe Coking and Chemical Co., Ltd., the main causes for abnormal gypsum dewatering which leads to abnormal operation of the system are determined quickly and accurately by using the qualitative analysis method according to the color, setting and separation of the slurry and the appearance of the dewatered slurry filter cake, including the high fly ash content, high CaSO₃·1/2H₂O content and high dissolved calcium hydroxide content in the slurry. By lowering the fly ash content, dredging the oxidation air pipeline, adding gypsum seed and timely adjusting the operation condition, the problem is solved, which indicates that the qualitative analysis method is suitable for emergency treatment of WFGD systems.