硫化物对裂解汽油一段加氢用Pd/Al_2O_3催化剂性能的影响

Effects of sulfur compounds on performance of Pd /Al_2O_3 catalyst for first-stage hydrogenation of pyrolysis gasoline

采用固定床反应器考察了多种硫化物(二硫化碳、二甲基二硫与噻吩)对裂解汽油一段加氢用Pd/Al2O3催化剂加氢性能的影响。在相同的工艺条件下,硫化物的毒性顺序为:二硫化碳>二甲基二硫>噻吩。CS2对催化剂加氢性能的影响最为明显,原料油中CS2质量分数达到6μg/g后,催化剂就迅速发生中毒,产品双烯值增高。催化剂失活的原因是CS2主要以物理吸附的方式占据催化加氢活性中心,导致催化剂对共轭烯烃与氢气失去吸附活性。

The effects of sulfur compounds such as carbon disulfide, dimethyl disulfide and thiophene on the performance of Pd/Al2 O3 catalyst for first-stage hydrogenation of pyrolysis gasoline are conducted with a fixed-bed reactor. The toxicity order is shown as： carbon disulfide 〉 dimethyl disulfide 〉 thiophene under the same process conditions. The poisoning effect of carbon disulfide on the reactivity of pyrolysis gasoline hydrogenation over Pd/Al2 O3catalyst is the most serious. The catalyst rapidly loses hydrogenation activity, leading to the increase of dienes values, when CS2 concentration of the feed stock reaches 6 μg/g. The possible cause of catalyst deactivation is that CS2 occupies the catalytic hydrogenation activity centers mainly by physical adsorption, which results in loss of adsorption activity of Pd/Al2 O3 catalyst for conjugated dienes and hydrogen.