国内炼油厂污水罐腐蚀现状及失效原因分析

Corrosion Status and Failure Reason Analysis of Sewage Tanks in Domestic Refineries

统计分析了国内多家炼油厂污水罐的腐蚀开裂现状及腐蚀介质成分,发现硝酸根是一个能引起应力腐蚀的重要腐蚀性成分。在分析了各腐蚀性成分的腐蚀机理和腐蚀产物的基础上,得出以下结论:硫化氢+氨+硝酸根+水造成的应力腐蚀是污水罐开裂泄漏的真正原因,其中湿硫化氢应力腐蚀是污水罐失效的主因,氨和硝酸根应力腐蚀是次因,且氯离子具有促进碱性环境中湿硫化氢应力腐蚀的作用。

The present situations of corrosion cracking of many sewage tanks and the composition of corrosive mediums in domestic refineries are statistically analyzed.It is found that nitrate is an important corrosive component that can cause stress corrosion.Based on the analysis of corrosion mechanism and corrosion products for different corrosive components,the following conclusions are drawn:the stress corrosion caused by hydrogen sulfide+ammonia+nitrate+water is the real reason for cracking and leakage of the sewage tanks,in which the stress corrosion caused by wet hydrogen sulfide is the main factor,the stress corrosion caused by ammonia and nitrate is secondary factor;and chloride ion has the effect of promoting wet hydrogen sulphide stress corrosion in alkaline environment.