裂解汽油一段选择性加氢的工艺条件研究

Operating Conditions for Selective Hydrogenation of Pyrolysis Gasoline in the First Stage

采用高压搅拌釜式反应器,在消除催化剂内外扩散影响的基础上,以环戊二烯、苯乙烯和1-己烯与溶剂正庚烷组成的混合物为模型化合物,对裂解汽油一段选择性加氢的操作条件进行了研究。发现当反应温度和压力升高时,各个组分的转化率都随之增高,但是双烯的加氢选择性变差。当单烯和双烯组分共存时,环戊二烯和苯乙烯优先进行加氢反应,当双烯浓度降至一定程度时,1-己烯才进行加氢。此外还采用固定床考察了温度、压力和氢油比对裂解汽油加氢的影响。结果表明,较合适的反应条件为313 K,2.5～3.0 MPa和氢油比25。

The selective hydrogenation of pyrolysis gasoline （pygas） over Pd/Al2O3 catalyst was investigated in an autoclave in the absence of internal and external transport limitation. The mixture composed of cyclopentadiene, styrene, 1-hexene and solvent n-heptane was used as a model compound to study the operation conditions of the first-stage selective hydrogenation of pygas. The results showed that the conversion of cyclopentadiene, styrene and 1-hexene increased with the increasing of the reaction temperature and pressure, while the selectivity of diolefin decreased. The cyclopentadiene and styrene were superior in hydrogenation, while the hydrogenation of 1-hexene became evident only when the concentration of diolefins decreased to a certain degree. Then effects of temperature, pressure and the volume ratio of hydrogen to pygas on hydrogenation were investigated in a fixed bed reactor. The results showed that the appropriate conditions were 313 K, 2.5-3.0 MPa and the volume ratio of hydrogen to pygas 25.