苯对Pt/Ga_2O_3/WO_3/ZrO_2和Pd/Al_2O_3/WO_3/ZrO_2催化剂上正己烷异构化反应的影响

Influence of benzene on isomerization of n-hexane over Pt/Ga_2O_3/WO_3/ZrO_2 and Pd/Al_2O_3/WO_3/ZrO_2 catalysts

研究了苯对Pt/Ga2O3/WO3/ZrO2(PtGWZ)和Pd/Al2O3/WO3/ZrO2(PdAWZ)催化剂上正己烷异构化反应的影响。结果表明,苯可影响PtGWZ和PdAWZ上正己烷异构化反应性能,苯含量越高影响越显著。与PdAWZ相比较,苯对PtGWZ上正己烷异构化反应的影响相对较小;苯对PtGWZ上正己烷异构化反应活性的影响是可逆的,撤除苯后PtGWZ对正己烷异构化的催化性能可完全恢复;苯对PtGWZ上正己烷异构化反应的稳定性没有影响。苯对PdAWZ上正己烷异构化反应活性的影响是不可逆的,PdAWZ用于含苯正己烷异构化反应催化剂会逐渐失活。热失重法积炭分析结果表明,相同条件下,含苯正己烷异构化反应后,PtGWZ上的积炭量较PdAWZ上的积炭量少。分析讨论了苯对PtGWZ和PdAWZ上正己烷异构化反应影响差异性的原因。

The effect of benzene on the isomerization of n-hexane over Pt/Ga2O3/WO3/ZrO2 （PtGWZ） and Pd/Al2O3/ WO3/ZrO2 （PdAWZ） catalysts were investigated comparatively. The results indicate that the activities of both PtGWZ and PdAWZ catalysts for n-hexane isomerization decrease with the increase of benzene amounts in the feed. Compared with PdAWZ catalyst, PtGWZ catalyst is less influenced by benzene. The inhibiting effect of benzene on the isomerization activities of PtGWZ is reversible and the activity for n-hexane isomerization can be fully recovered when benzene containing feed is replaced by pure n-hexane. However, the inhibiting effect of benzene on n-hexane isomerization activity of PdAWZ is irreversible. For the benzene containing feed, the deactivating effect can be observed on PdAWZ catalyst, but no deactivating effect on PtGWZ catalyst can be found. This deactivating effect is due to a rapid coke formation from cyclohaxane, which formed from benzene hydrogenation on the catalysts. The reasons for the different inhibiting effects of benzene on the isomerization activities of PtGWZ and PdAWZ catalysts are discussed.