Hydrogenation of aromatic compounds during gas oil hydrodewaxing: I. Effect of ruthenium content and method of nickel catalyst preparation

Ni-based (8 wt.% NiO) dewaxing catalysts for the hydroconversion of the hydroraffinate of oil fraction (d20 °C = 0.845 g/cm3; cloud point (CP) = −2 °C; aromatics = 25.8 wt.%; S = 25 ppm) were modified with Ru. The effect of Ru content (0.6, 0.75 and 0.9 wt.% of RuO2) and the methods of Ni catalyst preparation were examined. The catalysts were characterised by N2 sorption, TPR, ICP, XRD, SEM, XPS, H2 chemisorption. Activity was tested in a continuous-flow system at 6 MPa (LHSV, 2.5 h−1; H2:CH, 350 N m3/m3). NiO and RuO2 were found to exert a synergic effect on catalytic activity. The rise in RuO2 content from 0.6 to 0.9 wt.% increased the HDA of HON from 23 to 65% at 240 °C and was parallelled by a drop in CP (by about 15 °C). The effect of Ru was found to depend on the method of Ni catalyst preparation.