SRGO hydrotreating over Ni-phosphide catalysts on granulated Al2O3

Abstract

Abstract Ni-phosphides present a promising alternative to the conventional hydrotreatment NiMo sulfides. The hydrotreatment catalysts are supported on Al2O3 granules, and the similarly Al2O3 supported Ni-phosphide catalysts provide an interesting case for comparison. In this work the Ni-phosphide catalysts supported on Al2O3 granules were prepared using two procedures: 1) temperature-programmed reduction of “phosphite”-type precursor in hydrogen flow (TPR_I catalyst), 2) treatment of Ni nanoparticles with triphenylphosphine solution at elevated temperature (LP catalyst). The catalysts were characterized by ICP-AES chemical analysis, N2 physisorption, XRD, TEM, XPS, 27Al MAS NMR. The Ni2P particles were found in LP samples, while TPR method gives the mixture of Ni12P5 and Ni2P particles and amorphous AlPO4 on the alumina surface. The behavior of granulated Ni phosphide and conventional sulfided NiMo/Al2O3 catalysts was compared in hydroprocessing of straight-run gas oil (SRGO) at 340\u2009°C, 4\u2009MPa, V(H2)/V(feed) - 400 Nm3/m3, LHSV - 1,5\u2009h-1. Hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activity of nickel phosphide catalysts were shown to be lower in comparison with NiMo/Al2O3. Hydrotreating of S-containing model compounds (DBT, 4-MDBT, 4,6-DMDBT) was carried out over TPR_I catalyst, and a negative effect of dimethyl disulfide (DMDS) and acridin additions on the HDS activity was observed.