液化气及干气脱硫装置的腐蚀与防护

中国石化股份有限公司济南分公司的液化气及干气脱硫装置是该公司1.40Mt/a重油催化裂化装置的配套装置,自1996年开工运行以来,塔底重沸器和它的出口管线以及贫/富胺液换热器等部位多次发生腐蚀泄漏事故。液化气、干气脱硫装置的腐蚀属胺-H2S-CO2-H2O体系的腐蚀,温度以及杂质Cl-等对腐蚀有重要影响;当温度低于特定值时,上述体系的腐蚀十分微弱,在相变区域或高流速区域腐蚀则十分剧烈;而Cl-的聚集则会造成局部腐蚀破坏。采取及时补充新鲜溶剂,在溶剂系统加注缓蚀剂和采取隔绝空气(油封、氮封、内浮盘)措施,可取得良好的防护效果。

Corrosion of LPG and Dry Gas Desulfurization Units and Protection

A number of corrosion leaks occurred in the tower bottom reboiler, reboiler outlet pipelines and lean/rich amine heat exchanger in the LPG and dry gas desulfurization unit of 1.4 M t/yr heavy oil FCC unit in Jinan Petrochemical Company/SINOPEC. The corrosion is the corrosion of amine-H2-CO2-H2O system, on which the temperature and Cl- impurity have a greater impact. When the temperature is lower than a certain value, the corrosion of the above system is weak while at the phase-change section or high-velocity section, the sharp corrosion is obvious. The centralization of Cl- will lead to the corrosion failure. The equipment can be protected from corrosion by addition of fresh solvent in a timely manner and application of corrosion inhibitors in solvent system and isolation from air (oil sealing, nitrogen blanketing, using of internal floating deck).