火电厂用水量很大,其中循环水用量最大,占电厂用水总量的70％以上.为探索循环水高浓缩倍率运行控制技术,对纳滤工艺处理电厂循环水补充水进行研究,并在某电厂进行了中试试验,规模为18 m3/h.试验结果表明,在回收率为90％时,纳滤膜脱盐率70％左右,对Ca2+、Mg2+、SO42-等二价离子的去除率大于80％,产水COD质量浓度≤2 mg/L.以纳滤产水为试验水源进行循环水静态阻垢试验及挂片腐蚀试验,结果表明,若采用纳滤产水作为循环水补充水,循环水的极限浓缩倍率可高达33.98,循环水系统将可实现超高浓缩倍率运行和冷却塔零排污,节水效果和环保效益均显著.%Large quantities of water are required in thermal power plants,of which primarily the circulating cooling water accounts for over 70％ of the total water consumption.To explore the operating control technique of the circulating cooling water with high concentration ratio,the make-up water treatment with nanofiltration (NF) processing is studied and tested in a power plant with the processing capacity of 18 m3/h.The test results show that at the recovery of 90％,the desalination rate is about 70％,while the removal rate of divalent ions,such as Ca2+,Mg2+ and SO42-,is over 80％ and the COD of yielding water is not more than 2 mg/L.Then,the NF processed water is used in the static scale inhibition test and the coupon corrosion test.The test results show that the concentration ratio of the circulating water can be maximized by as much as 33.98 times,and at this time,the circulating water system can operate at high concentration ratio with zero cooling tower discharge,which exhibits remarkable water-saving effect and environmental benefits.
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