UPGRADING OF BITUMEN-DERIVED HEAVY OILS OVER A COMMERCIAL HDN CATALYST

The hydrotreatment of PR Spring bitumen-derived heavy oils was achieve d in a fixed-bed reactor over presulfided commercial NiMo/alumina hydr odenitrogenation catalysts. The extents of heteroatom and metal remova l and of Conradson carbon residue (CCR) and residuum ( > 811 K) conver sion were determined as a function of process operating variables: tem perature (625-685 K) and liquid hourly space velocity (0.14-0.80 h(-1) ). Pressure and hydrogen/oil ratio were fixed at 13.7 MPa and 890 m(3) m(-3) in all experiments. Differences between heteroatom removal and residuum conversion and between CCR conversion and metal removal were investigated and product distributions and yields were studied. The de gree of Ni, N and S removal and of CCR and residuum conversion increas ed significantly as reciprocal LHSV and temperature increased. The res iduum fraction ( > 811 K) became significantly converted with increasi ng residence time and the yields of gas oil (617-811 K), distillate (4 77-617 K), naphtha (i.b.p.-477 K) and C-1-C-4 gases increased continuo usly. Residuum was significantly converted to volatiles at higher temp eratures. The yields of distillate, naphtha and gas increased rapidly at higher temperatures. (C) 1997 Elsevier Science Ltd.