Nickel Catalysts For The First-stage Selective Hydrogenation Of Pyrolysis Gasoline (PG) Research

The main task of this paper was based on the review of the progress on catalysts for the first-stage selective hydrogenation of pyrolysis gasoline(PG) and the analysis of the situation of these researches.Using equivalent volume impregnation method,were developed new Ni/Al₂O₃ and Ni/TiO₂-Al₂O₃ catalysts first stage selective hydrogenation of PG. With N₂physics-sorption,XRD(X-ray diffraction),H₂-TPR(H₂-temperature programmed reduction),and SEM(Scanning Electron Microscopy) was used to study and characterize preparation of Ni/Al₂O₃ and Ni/TiO₂-Al₂O₃ the first stage selective hydrogenation of PG catalyst.And evaluate the catalysts activity and selectivity.1,BET results show that the surface area almost the same when Al₂O₃ carrier calcination temperature at 900℃,TiO₂-Al₂O₃ at 850℃,but between 20～110nm,TiO₂-Al₂O₃ carrier pore volume bigger than carriers Al₂O₃,this is more conducive to internal diffusion control reaction of PG selective hydrogenation.2,XRD results show that the catalysts crystal phase have no Ni metal diffraction peaks.This means that the catalysts does not exist phase metallic Ni or Ni particle diameter less than 2nm.And about TiO₂-Al₂O₃ support,TiO₂ crystal phase isβ-TiO₂,and is Al₂O₃amorphous.3,Ni/TiO₂-Al₂O₃ reduction temperature is lower than Ni / Al₂O₃ catalysts.Therefore Ni interaction with TiO₂-Al₂O₃ carrier weaker than Ni and Al₂O₃,this will be beneficial to sulfiding and activation of catalyst.4,Through small-scale evaluation,results show that the Ni/TiO₂-Al₂O₃ catalyst per unit mass metal hydrogenation activity better than Ni/Al₂O₃ catalyst.