Abstract:

Based on the specific conditions of using primary reverse osmosis desalinated seawater as make-up water in the circulating cooling water system of a coastal power plant, and considering the technical requirements for system corrosion and scale inhibition, a scale and corrosion inhibitor suitable for 9-fold concentrated water quality was developed, and its corrosion inhibition mechanism was revealed. The results showed that the composite scale and corrosion inhibitor was composed of SC215 scale and dispersion agent (mainly hydrolyzed polymaleic anhydride, HPMA), 2-phosphate-1,2,4-tricarboxylic acid butane (PBTCA), aminotrimethylphosphonic acid (ATMP), and Zn²⁺. The optimal dosages were 8, 4, 4, and 3.6 mg/L, respectively. Under the experimental conditions of 50 ℃, 80 r/min, and 72 hours, the corrosion rate of 20^# carbon steel could be reduced to 0.015 5 mm/a, with a corrosion inhibition rate as high as 98.83% in 9-fold prepared water. Electrochemical analysis indicated that this agent acted as a mixed-type corrosion inhibitor, primarily through cathodic inhibition, and the corrosion electrochemical reaction was primarily controlled by the charge transfer process. Taking the system with a circulating water volume of 50 000 m³/h as an example for economic evaluation, the cost of chemical raw materials was about 467 000 yuan/a, which had good engineering application prospects.

Key words: scale-corrosion inhibitor, seawater desalination, primary product water, 9-fold concentrated

摘要：

针对某滨海电厂循环冷却水系统采用反渗透海水淡化一级产品水作为补充水的特殊工况，结合系统防腐与阻垢技术要求，研发了一种适用于9倍浓缩水质的阻垢缓蚀剂配方，并揭示了其缓蚀机理。结果表明，该复合阻垢缓蚀剂由SC215阻垢分散剂〔以水解聚马来酸酐（HPMA）为主〕、2-膦酸基-1，2，4-三羧酸丁烷（PBTCA）、氨基三亚甲基膦酸（ATMP）和Zn²⁺组成，最佳投加质量浓度依次为8、4、4、3.6 mg/L。在50 ℃、80 r/min、72 h的试验条件下，在9倍配制水中可使20^#碳钢的腐蚀速率降至0.015 5 mm/a，缓蚀率高达98.83%。电化学分析表明，该药剂属于以阴极抑制为主的混合型缓蚀剂，腐蚀电化学反应主要受电荷传递过程控制。以循环水量为50 000 m³/h的系统为例进行经济性评估，药剂原料成本约为46.7万元/a，具备良好的工程应用前景。

关键词: 阻垢缓蚀剂, 海水淡化, 一级产水, 9倍浓缩

CLC Number: 

• P747

• TQ085