双塔双循环脱硫除雾器故障分析及对策研究

除雾器是湿法烟气脱硫系统关键设备之一，其性能直接影响脱硫系统甚至机组的安全运行。以某660 MW燃煤机组双塔双循环脱硫系统除雾器堵塞并导致部分模块掀翻故障为例，对影响除雾器性能的空塔流速、安装空间、冲洗水压等设计因素，入口烟尘浓度，除雾器冲洗水量，浆液、石膏及结垢物成分等进行了全面分析。结果表明：脱硫系统水平衡控制不当以及二级塔pH值控制偏高是除雾器故障主要原因。为降低除雾器运行风险，针对双塔双循环脱硫系统水平衡和浆液pH值控制，给出了合理建议。

Failure Analysis and Countermeasures of Double Tower Double Cycle Desulfurization Demister

As one of the most critical equipments in wet flue gas desulfurization system, the performance of the demister will directly affect the operation security of the desulfurization system and even compromise the generation unit itself. This paper took the failure scenario of the double tower double cycle desulfurization of a 660 MW coal-fired unit as an example, in which the blockage of demister caused overturn fault on some modules. The comprehensive analysis was also conducted regarding the demister design factors (such as the air velocity within the cooling tower, the mounting space, the pressure of flush water etc.), the concentration of entrance smoke, the rinse water volume of demister as well as the components of slurry, gypsum and fouling materials. It was found that the improper water balance control of desulfurization system and the high pH value settings of the secondary tower were the major culprits of demister failure. In order to reduce the risk of operation failure of the demister, some reasonable suggestions were given for the control of water balance and slurry pH value of the double tower double cycle desulfurization system.