摘要：

某火电厂循环冷却排污水经净化处理后再次回用，但净化处理系统反渗透（RO）膜单元运行中出现故障，存在反渗透段间压差快速上升，产水率和脱盐率下降等现象，通过对反渗透进水水质分析、循环冷却系统水源变化分析、膜元件标准测试、膜元件解剖、膜片染色试验、污染物灼烧失重分析和污染物成分鉴定等工作分析RO膜单元运行故障原因。结果表明，采用城市中水作为循环冷却系统补水后，经循环冷却系统浓缩后的排污水中有机物、钙镁离子、磷酸根离子和碱度等含量偏高，是造成反渗透膜污堵的主要原因，膜污染物以磷酸盐无机污垢为主要成分，有机污垢为次要成分，同时伴随硅垢、铁垢等污垢物。采取增加碱加药装置和非氧化杀菌剂加药装置、修复硫酸加药装置、对现有反渗透膜进行彻底离线化学清洗等措施，使反渗透系统恢复正常运行，有效解决了运行中反渗透膜频繁污堵问题。

关键词: 火电厂, 循环冷却排污水, 回用, 反渗透, 膜污堵

Abstract:

After purification treatment, the circulating cooling wastewater from a certain thermal power plant was reused. However, malfunction occurred during the operation of the reverse osmosis (RO) membrane unit in the purification treatment system, resulting in a rapid increase of pressure difference between the RO sections and a decrease of water production and desalination rates. Through analysis of inlet water quality of reverse osmosis, changes in the water source of circulating cooling system, membrane element standard testing, membrane element dissection, membrane staining test, foulants burning weight loss analysis, and foulants component identification, etc., the cause of malfunction of RO membrane unit was analyzed. The results indicated that after using urban reclaimed water as influent of circulating cooling system, the concentrated wastewater from the circulating cooling system contained high levels of organic matter, calcium and magnesium ions, phosphate ions, and alkalinity, which were the main causes of reverse osmosis membrane fouling. Membrane foulants were mainly composed of inorganic phosphate fouling, with organic fouling as a secondary component, accompanied by fouling such as silicon fouling and iron fouling. Measures such as adding alkali dosing devices and non-oxidizing bactericide dosing device, repairing sulfuric acid dosing device, and thoroughly offline chemical cleaning of reverse osmosis membranes were taken to restore normal operation of the reverse osmosis system, effectively solving the problem of frequent fouling and blockage of the reverse osmosis membrane during operation.

Key words: thermal power plant, circulating cooling wastewater, reuse, reverse osmosis, membrane fouling

中图分类号: 

• X703

• TM628