pH值对冷冻盐水成分及腐蚀速率的影响

Impacts of pH on Freezing Brine Compositions and Corrosion Rate

A企业现场冷冻盐水系统须在弱碱性条件下才能正常工作，目前该系统出现异常现象，整体呈酸性，pH值低至4．11，系统腐蚀已非常严重。为解决这一问题，通过旋转挂片质量损失法实验来评价pH值对冷冻盐水系统的成分及腐蚀速率的影响，从而寻找出更合理的pH值范围。由实验结果得出，冷冻盐水系统在弱碱性pH值7-9条件下药剂的缓蚀效果最好；当缓蚀剂加药质量分数为0．5％时，用碱性药剂将A企业现场冷冻盐水的pH调至弱碱性，可将冷冻盐水系统中大量的铁成分以沉淀方式去除，此时可以大大的降低系统的腐蚀速率，从而达到缓蚀效果，维持系统的稳定运行。

The freezing brine system in a company can only work normally in the weak alkali conditions. Now the system becomes acidic and the pH is as low as 4.11, which indicate that the system suffers from very serious corrosion. To solve this problem, the weight - loss coupon tests have been performed to evaluate the impacts of pH on freezing brine compositions and corrosion rate so as to find out a more appropriate range of pH value. The test results show that the corrosion inhibitor offers excellent efficiency when the pH of freezing brine is weak alkaline of 7 -9. When the dosage of corrosion inhibitor is 0.5% and the pH of freezing brine system is adjusted to weak alkaline by using alkaline chemicals, a large amount of iron in freezing brine system can be removed by precipitation. As the result, the corrosion rate of the system can be greatly reduced. The corrosion inhibition objectives and the stable operation of the system have been achieved.