S Zorb装置进料泵运行故障剖析

Analysis of accidents in operation of feed pump of S Zorb unit

S Zorb装置主要用于催化裂化汽油的脱硫,能以较低的辛烷值损失生产硫质量分数在10μg/g以下的超低硫汽油,较易脱除一般加氢精制装置难以脱除的噻吩类硫。中国石化青岛炼油化工有限责任公司1. 5 Mt/a S Zorb装置自2015年9月开工至今,已运行3 a,装置原料进料泵连续几次出现设备故障,直接影响了装置平稳、长周期运行。分析了原料进料泵的故障原因是原料中活性硫化氢、噻吩类化合物与铁反应生成硫化亚铁,非活性硫化物热分解后生成活性硫,进一步又与铁反应生成硫化亚铁等腐蚀产物,加之过滤器密封不严,导致泵运行故障,提出了整改措施。

S Zorb unit is mainly operated to remove sulfur from FCC gasoline so as to produce ultra-low sulfur gasoline with sulfur lower than 10 ppm at a lower loss of octane number. It is much easier to remove thiophene sulfur than other general hydrotreating units. The 1. 5 MM TPY S Zorb unit in SINOPEC Qingdao Refining & Chemical Co.,Ltd. has been operating for more than 3 years since its start-up in September,2015.The feed pump of the unit has experienced several failures,which have directly affected the stable long-term operation of the unit. The root causes of accidents of feed pumps are analyzed. It is concluded that the main causes are: the active hydrogen sulfide and thiophene compounds in the feedstock react with iron to form iron sulfide; After thermal decomposition,the non-active sulfides form active sulfur,which reacts with iron to form corrosion products like iron sulfide,etc. In addition,the seal of filter does not work properly,which causes the operation accident of pump. Associated counter measures are recommended.