循环水不锈钢换热器抗氯离子应力腐蚀研究  

Study on Resistance Against Stress Corrosion off Chlorine Ions of Cooling Water Stainless Steel Heat Exchangers

作　　者：董绍平[1] 

机构地区：[1]中国石油化工股份有限公司镇海炼化分公司,浙江宁波315207

出　　处：《石油化工腐蚀与防护》2012年第1期36-40,共5页Corrosion & Protection In Petrochemical Industry

摘　　要：炼油、化工装置中换热器占总设备数量的40%左右,占总投资的30%～45%,换热设备中大约有1/3是水冷器,其中不锈钢换热器容易受循环冷却水中Cl-影响而发生应力腐蚀,这就制约着有污水回用的循环水系统提升浓缩倍数。通过调研得出这种腐蚀受Cl-的含量、温度影响较大,pH值也有一定的影响。文章提出了当温度为50～80℃及pH值大于8时,工业循环水的Cl-质量浓度最大可达1 000 mg/L。还介绍了列管式和盘管式换热器的应力腐蚀开裂情况,并依据对现场调研结果得出换热器易发生应力腐蚀的部位主要包括胀接部位、U形管的弯曲部位、折流挡板和换热管其它部位等。并建议在循环水系统内进行挂片试验进一步研究不同因素和换热器不同部位对应力腐蚀的影响,以便提出防护措施。The heat exchangers in petroleum refineries and chemical plants account to about 40% of the total equipment quantity and 30% -45% of total equipment investment. In heat exchange equipment, one third is water cooler. The stainless steel heat exchangers are subject to stress corrosion caused by C1 - in cooling water, which will limit the increase of concentration of cooling water system. The investigation study confirms that the C1- content and temperate have a greater impact on the corrosion and pH value also has a certain influence. At a temperature of 50 - 80 ~C and pH value of 8, the maximum mass concentration of C1 - in industry cooling water can be as high as 1000 mg/L. The stress corrosion cracking （SCC） of tube heat exchangers and coil heat exchangers is introduced. The field investigation has found that the locations which are subject to stress corrosion in heat exchanger are mainly expanded connections, bent of U tube, rod baffles, heat exchanger tubes, etc. It is suggested to have coupon testing in cooling water system to further study the impact of different factors and different locations on stress corrosion so as to propose appropriate corrosion protection measures.

关 键 词：不锈钢换热器 氯离子 应力腐蚀 

分 类 号：TG172.9[金属学及工艺—金属表面处理] TQ050.9[金属学及工艺—金属学]