柠檬酸清洗工艺在新建超临界锅炉上的应用

Experience of citric acid pickling process for new supercritical boiler

神华河北国华沧东发电有限责任公司新建的四号机组采用国产超临界锅炉,投产前采用柠檬酸酸洗、凝结水泵大流量水冲洗、低温柠檬酸漂洗、双氧水钝化的化学清洗工艺。清洗实践表明,锅炉酸洗后水冲洗时间仅1.83h即冲洗合格,冲洗排水铁含量降至14mg/L;低温柠檬酸漂洗工艺有效控制了漂洗过程的铁含量始终在300mg/L以下;碱性双氧水钝化取得了优良的钝化效果,酸性硫酸铜点滴变色时间达到了16s。

The homemade unit 4 boiler of Shenhua Hebei Guohua Cangdong Power Generation Co., Ltd. is a supercritical boiler, which was pickled before put into production. The pickling process consists of citric acid cleaning, large flow flushing with condensate pump, citric acid rinsing, and hydrogen peroxide passivating. The field chemical cleaning showed that it takes only 1.83 hours for the flush drain containing 14mg/L Fe to reach requirement, the low-temperature citric acid rinse efficiently controls Fe content in the rinse solution less than 300 mg/L, and that basic hydrogen peroxide passivation results in excellent passivating film, upon which blue acidic copper sulfate changes red after 16 seconds.