某燃煤发电厂反渗透膜系统脱盐率下降案例分析

A Case Study on the Decline of the Desalination Rate in the Reverse Osmosis Membrane System of a Coal-fired Power Plant

以某燃煤发电厂反渗透系统脱盐率异常下降事件为案例,研究了膜脱盐率下降原因,指出预处理系统杀菌剂加药量调整后,还原剂加药量没有相应的调整导致反渗透膜进水余氯超标,是导致膜被轻度氧化的直接原因;通过解剖实验,发现膜片有背压破坏现象,排查出清洗管路设置错误是导致清洗中分段产生背压的直接原因;提出了调整还原剂加药量、更改管路连接及设置膜片背压联锁值的解决措施,并成功恢复了反渗透系统的正常运行。

Taking an abnormal decrease of the desalination rate in the reverse osmosis system of a coal-fired power plant as an instance,the reasons for the decrease of the desalination rate in the membrane were analyzed.After adjusting the dosage of germicide in the pre-treatment system,the dosage of reducing agent was not adjusted accordingly,leading to the excess of residual chlorine in the influent,which caused the mild oxidation of the membrane directly;By anatomical tests,the membrane was damaged owing to the back-pressure,and it was found that the incorrect setting of the cleaning pipeline was the direct reason of back-pressure generation in the cleaning section;Several solutions including adjusting the dosage of reducing agent,changing the pipe connection and setting the interlock value of the diaphragm back pressure were proposed,in which the normal operation of the reverse osmosis system was restored successfully.