THERMAL-CONVERSION OF PR SPRING BITUMEN-DERIVED HEAVY OIL IN THE PRESENCE OF NA ALUMINA/

The thermal cracking of PR Spring bitumen-derived heavy oils in the pr esence of hydrogen was studied in a fixed-bed reactor as a function of process operating variables. The reactor was filled with a catalytica lly inert sodium exchanged alumina. The packing consisted of an alumin a hydrodenitrogenation catalyst support which had been impregnated wit h 2 wt.% sodium to reduce the acidity of the alumina. Thermal reaction s were investigated with regard to denitrogenation, desulfurization, d emetallation, Conradson carbon residue (CCR) reduction and residuum co nversion. The process operating variables investigated were temperatur e (642-683 K), and WHSV (0.25-0.74 h(-1)). The reactor pressure and hy drogen-to-oil ratio were fixed at 13.7 MPa and 890 m(3)/m(3) (5000 scf H-2/bbl); respectively, in all experiments. The product distributions and yields were also determined as a function of process operating va riables. Residuum conversion over the sodium-impregnated catalyst supp ort was greater in all cases relative to nitrogen and sulfur removal d ue to thermal cracking of the residuum. Only low levels of heteroatom conversion were possible via thermal reactions. The extent of nitrogen removal over the sodium-impregnated catalyst support was lower than t hat of all other classes of component-types. Significant levels of CCR conversion were obtained despite the absence of metal sulfides on the alumina and were attributed to hydrothermal conversion. (C) 1998 Else vier Science B.V. All rights reserved.