OCT-MD装置保护反应器压力降上升的原因分析

Cause analysis of increase of pressure drop in guard reactor of gasoline hydrotreating unit

分析了中国石油化工股份有限公司武汉分公司OCT-MD装置预加氢保护反应器压力降快速提高的原因,并提出撇头处理方案。由于Ⅱ套FCC装置气压机运行不正常,润滑油进入稳定汽油中,FCC汽油实际胶质由正常不大于5.0mg/（100mL）大幅度提高到10.0～27.0mg/（100mL）。OCT-MD装置预加氢保护反应器压力降快速升高,由开工初期0.08MPa增加到0.28MPa。上层撇头焦粉中SO3,Na2O,Fe2O3,WO3的质量分数分别达到50.0%,22.0%,8.0%,6.0%左右,表明装置脱臭单元脱水分离不彻底,微量Na,Co等元素带入反应器,润滑油、二烯烃等结焦前身物以Na,Fe为晶核聚合结焦,是造成反应器压力降上升的原因。另外,Ⅱ套FCC装置运行正常情况下,稳定汽油、脱臭汽油、重馏分性质基本稳定,不会造成预加氢保护反应器压力降快速提高。

The causes of rapid increased pressure drop in the guard reactor in the OCT-MD hydrtreating unit were studied,and skimming was proposed. Due to the abnormal operation of the gas compressor in FCC Unit Ⅱ and the lubricant oil entering the stabilized gasoline,the existing gum in FCC gasoline was significantly increased from ≤5. 0 mg /（100 m L） to 10. 0 ～ 27. 0 mg /（100 m L）,and the pressure drop in the guard reactor of OCT-MD Unit was rapidly raised from 0. 08 MPa to 0. 28 MPa. The SO_3,Na_2 O,Fe_2O_3and WO_3 in the powdered coke of skimming catalyst reached 50. 0%,22. 0%,8. 0% and 6. 0% respectively. All these show that dehydration separation is not complete in the sweetening section of FCC Unit and trace amounts of sodium and cobalt is entrained into the reactor. The cause of the increase of pressure drop in the reactor is that the coking precursor of lubricant oil and diolefin is polymerized coking based on sodium and iron as crystal nucleus. During the normal operation of FCC Unit Ⅱ,the basic properties of stabilized gasoline,sweetened gasoline and heavy distillates are normal,which will not lead to the rapid increase of pressure drop in prehydrogenation guard reactor.