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某制盐公司采用电渗析设备,拆开内部结构检查时发现负极板有严重的腐蚀现象,负极板材质为316L。本文重点结合电渗析设备在生产过程中的实际运行条件,分析负极板腐蚀原因,而制定出合理的预防措施。分析结果表明:(1)负极板腐蚀属于坑蚀、缝隙腐蚀、氢脆现象,腐蚀现象深入基体内部,是在综合因素共同作用下的结果;(2)在电渗析运行过程中可以在物料中加入适量硝酸作为缓蚀剂,从而达到降低对不锈钢腐蚀作用。(3)电极板与电极连接处采用低氢焊条。酸洗时,选用缓蚀剂或采取降低引入氢量的工艺。在运行过程中定期排出ED设备管道中的气泡;(4)由于316L材质是无法满足生产工艺设备性能的要求,需合理选取负极板材质,建议宜采用TA8材质。
A salt company using electrodialysis equipment, open the internal structure inspection revealed a serious corrosion of the negative plate, negative plate material is 316L. This article focuses on the actual operation of electrodialysis equipment in the production process, analyze the causes of negative plate corrosion, and to develop reasonable preventive measures. The results show that: (1) The corrosion of the negative plate belongs to pitting corrosion, crevice corrosion and hydrogen embrittlement, and the corrosion phenomenon goes deep into the matrix, which is the result of the combined factors; (2) During the electrodialysis operation, Adding appropriate nitric acid as a corrosion inhibitor, so as to reduce the corrosion of stainless steel. (3) the electrode plate and electrode connections using low hydrogen electrode. Pickling, the choice of corrosion inhibitor or take to reduce the amount of hydrogen introduced into the process. (4) As the 316L material is unable to meet the requirements of the production process and equipment performance, it is necessary to select the material of the negative electrode plate reasonably, it is recommended to adopt the TA8 material.