湿式氨法烟气脱硫工艺中SO_4^(2-)对Cl^-点蚀的影响研究  

Effects of SO_4^(2-) on Cl^- Pitting Corrosion in Wet Ammonia Desulfurization Process

作　　者：邹洋 刘希武 许兰飞 李辉 

机构地区：[1]中石化炼化工程(集团)股份有限公司洛阳技术研发中心,河南洛阳471003

出　　处：《石油化工腐蚀与防护》2017年第5期6-8,共3页Corrosion & Protection In Petrochemical Industry

基　　金：中国石油化工股份有限公司科技开发项目"烟气净化过程中的腐蚀机理及合理选材技术研究"(15111R110)

摘　　要：采用循环动电位极化法研究了模拟湿式氨法烟气脱硫吸收液环境下SO_4^(2-)对Cl^-引起的304L不锈钢和316L不锈钢点蚀的影响。研究结果表明:随着SO_4^(2-)含量与Cl^-含量的比值升高,点蚀电位升高,点蚀不易发生;在质量分数为20%的(NH_4)_2SO_4溶液中,当Cl^-质量分数低于15 000μg/g时,304L不发生点蚀;Cl^-质量分数低于16 000μg/g时,316L不发生点蚀。从离子竞争吸附的角度对SO_4^(2-)抑制Cl^-点蚀的作用机理进行了分析。在实际湿式氨法烟气脱硫吸收液环境下,Cl^-的质量分数一般控制在15 000μg/g以下,选用304L不锈钢即可满足现场工况要求。By adopting the method of cyclic potentiodynamic polarization,influences of SO_4^（2-） on Cl^-pitting corrosion on 304 L and316 L stainless steels was studied under the simulated absorption solution environment in wet ammonia desulfurization process. The results showed that pitting corrosion was less likely to occur with the increase of pitting potential and content ratio of SO_4^（2-） to Cl^-;304 L was immune to pitting corrosion when mass fraction of（ NH_4）_2 SO_4 was 20% and Cl^-content was below 15 000 μg/g; 316 L stainless steel was immune to pitting corrosion when mass fraction of Cl^-was below 16 000 μg/g. Mechanism of SO_4^（2-） inhibition on Cl^-pitting was analyzed from the viewpoint of ion competitive adsorption. Generally,mass fraction of Cl^-controlled within 15 000μg/g and hence 304 L stainless steel was enough under the actual environment of wet ammonia desulfurization absorption solution.

关 键 词：烟气脱硫 点蚀 SO42- Cl- 竞争吸附 

分 类 号：TG172[金属学及工艺—金属表面处理] X742[金属学及工艺—金属学]