催化裂化汽油加氢装置床层压力降大的原因与对策

Causes of high pressure rise in the bed of FCC gasoline hydrotreating unit and countermeasures

中化弘润石油化工有限公司催化裂化汽油加氢装置存在一级反应器(一反)床层压力降升高的问题,对床层杂质组分的分析发现,一反分配盘和积垢篮内的黑色粉末中碳质量分数分别为69.6%和64.9%,确定引起床层压力降升高的根本原因是结焦物积垢。从积炭的来源进行推断,结焦物来源于一反进料换热器壳程,脱落后被带入一反床层。采取的应对措施为:对装置原料控制及工艺操作进行优化;加强原料控制;提高氢油比;一反进料换热器壳程出口温度降低约20℃;充分发挥一反保护剂的作用;从而减缓了催化剂表面的结焦趋势。通过调整,装置一反床层压力降上升问题得到有效控制,2016年9月装置开工运行至2017年9月一反床层压力降维持稳定(60~75 k Pa),基本解决了一反床层压力降升高问题,保证了装置的长周期平稳运行。

The 1 st-stage reactor of the FCC gasoline hydrotreating unit of SINOCHEM Hongyun Petrochemical Co.,Ltd.suffered from high pressure drop in the reactor bed.The analysis of the residues in the reactor bed has found that the percentages of carbon contents in the black particles in the distributor and fouling basket are 69.6%（w） and 64.9%（w） respectively.It is concluded that the culprits of rising pressure drop of reactor bed are the fouling of coking materials.To trace the source of coke accumulation,it is concluded that the coking materials come from the shell side of feed exchanger of 1 st-stage reactor,which are carried over to the bed of 1 st-stage reactor after spalling.The countermeasures are：the feedstock and process operating conditions of the unit are optimized;the hydrogen to oil ratio is increased;the outlet temperature of the shell side of heat exchanger for the 1 st-stage reactor feed is lowered by about 20 ℃;and the coking tendency is reduced.The performances of guard catalysts of 1 st-sage reactor are put into full play.At the same time,the coke formation on the surface of catalysts is mitigated.The pressure drop rise is effectively brought under control by adjusting the 1 st-stage reactor operation.The pressure drop of the 1 st-stage reactor bed remained stable between September,2016 when it was started up and September,2017.In this time period,the pressure drop in the reactor bed was maintained at 60 - 75 kPa,which has basically solved the problem of rising pressure drop of 1 st-stage reactor bed and ensured the long-term stable operation of the unit.