汽油和柴油加氢装置石脑油烯烃含量高的对策

Countermeasures for high olefins in naphtha of gasoline and diesel hydrotreating units

中国石油化工股份有限公司石家庄炼化分公司汽油、柴油加氢装置的石脑油烯烃含量从2011年12月开始逐渐升高,2012年1—2月由于另一套液相加氢装置开工,装置因原料不足降处理量后烯烃含量略有好转,3月恢复处理量后烯烃质量分数在0.8%左右,2012年9月石脑油烯烃质量分数高达1.18%以上,而且居高不下,到11月石脑油烯烃含量偏高已危及到石脑油产品出厂。通过对反应器出口及换热器前后油品质量分析数据的分析,催化剂活性严重下降导致石脑油烯烃含量增大的主要原因,由于生产任务制约装置无法停工换剂。通过逐渐提高加氢深度的办法应对石脑油烯烃高问题,即控制循环氢纯度87%以上;将反应器入口温度从350℃提高到360℃,维持反应器床层最高温度390℃以上;提高高分压力至7.2 MPa;降低处理量至70 t/h等措施维持装置运行,降低了石脑油烯烃含量,保证了石脑油产品合格出厂。

The olefins in the naphtha of gasoline and diesel hydrotreating units in SINOPEC Shijiazhuang Refining Chemical Co.,Ltd. began to rise since December 2011. The olefin in naphtha gradually began to be accepted in January and February,2012 because of the reduction of processing capacity due to the insufficient feedstock supply of a liquid-phase hydrotreating unit. The olefin remained at about 0. 8% after the processing capacity was restored in March,2012. In September,2012,the mass percentage of olefins in naphtha rose to over 1. 18% and remained at the high level till it was not accepted for going out of plant in November,2012. It is known from the analysis of the oil products at the outlet of reactor and inlet and outlet of the heat exchanger that the rising olefins in naphtha were caused by the serious dropping of catalyst activity. Due to the requirement of production,the unit had to be kept in operation without shutting down for catalyst replacement.The olefins in naphtha was finally reduced to accepted level by deepening hydrogenation processing,controlling the purity of recycle hydrogen at over 87%,elevating the reactor inlet temperature form 350 ℃ to 360 ℃,maintaining the reactor bed temperature at over 390 ℃,raising the pressure of high pressure separator to7. 2 MPa and reducing the processing capacity to 70 t/h. The specifications of naphtha product were accepted for going out of plant.