典型汽油加氢流程中管壳式换热器局部腐蚀的分析研究

Analysis and research on local corrosion of tube shell heat exchangers in the typical gasoline hydrogenation process

针对某石化公司在大检修期间换热器中存在的腐蚀问题,特别是发生严重腐蚀的换热器进行宏观检测,超声波检测分析。发现换热器发生腐蚀失效的主要原因是原油中富含了氯、氮、硫等离子,形成HCl+H2S+NH3+H2O等腐蚀体系,从而导致换热管束、管板发生了严重的局部腐蚀,包括换热管束的孔蚀、管束与折流板处以及管板接口处的缝隙腐蚀。针对上述现象,本文依据现场腐蚀情况以及工艺流程,探讨了腐蚀机理以及防腐措施。

A petrochemical company existed some problems of heat exchangers in corrosion during the overhaul. We made macro detection and analysis of ultrasonic testing for the heat exchangers where it developed seriously. We figure out that the corrosion of the heat exchangers failure was mainly due to the crude oil which is rich in chlorine, nitrogen, and sulfur plasma, forming the corrosion system of HCI＋H2S＋NH3＋H2O. Consequently it leads to a heat exchange tube and tube plate that occurred serious beam local corrosion, including heat exchange tube bundle of pitting corrosion, tube bundle and baffle plate and tube plate joints of crevice corrosion. In view of the above phenomenon, this paper discusses the corrosion mechanism and corrosion protection measures according to the corrosion situation and technological process.