全馏分催化汽油抽提降苯工艺研究

Process of benzene reduction via extraction from full-range catalytic gasoline

针对国Ⅵ汽油标准下催化汽油存在的苯含量超标问题,通过液液抽提的方式,对全馏分催化汽油进行了降苯工艺研究。通过对12种溶剂进行筛选,确定了最优的抽提溶剂乙二醇(EG);考察了以EG为抽提溶剂条件下,萃取时间、温度、溶剂比对抽提效果的影响;并进行了炼厂全馏分催化汽油的九级离心萃取实验。实验结果表明,EG具有优异的动力学性能,在5 min内即可与原料达到液液相平衡;提高溶剂比对萃取选择性影响不大,但会显著提高苯的脱除率;提高温度同样会提高苯的脱除率,但会降低萃取选择性;在优选实验条件下,苯含量最高可由原料的1.37%(w)降低至0.64%(w),脱除率达64%(φ),同时可保证其余芳烃收率在78%以上。

To address the issue of excessive benzene content in catalytic gasoline under the ChinaⅥgasoline standard,a study was conducted on the benzene reduction process of full-range catalytic gasoline using liquid-liquid extraction.Ethylene glycol(EG)was identified as the optimal extraction solvent after screening 12 solvents.The effects of extraction time,temperature,and solvent ratio on the extraction efficiency were investigated using EG.The results indicate that EG exhibits excellent kinetic performance,achieving liquid-liquid equilibrium with the feedstock within 5 min.Increasing the solvent ratio has little effect on the extraction selectivity but significantly increases the benzene removal efficiency.Raising the temperature also increases benzene removal efficiency but reduces extraction selectivity.In a nine-stage centrifugal extraction experiment with full-range catalytic gasoline,the benzene content is reduced from 1.37%(w)to a maximum of 0.64%(w),achieving a removal efficiency of 64%(φ),while maintaining the yield of other aromatic hydrocarbons above 78%.