Characteristics of CANMET coprocessing distillates at different coal concentrations

Abstract

The effect of feed coal concentration on the characteristics of gross and fractionated coprocessing distillates was investigated. Elemental analysis, 1H n.m.r., high performance liquid chromatography (h.p.l.c.) and field ionization mass spectrometry (f.i.m.s.) were used in this study. The distillates (205–525 °C) were obtained by coprocessing Forestburg subbituminous coal at three concentration levels, 3.7, 23.9 and 39.5 wt% (based on a maf slurry feed) and Cold Lake vacuum bottoms from Alberta in a nominal 1 kg/h bench-scale unit. Gross distillate characteristics as determined by elemental and 1H n.m.r. analyses indicate that as coal concentration is increased, more coal-derived liquids contribute to the distillate. For detailed analysis, distillates from 3.7 and 23.9 wt% coal concentration were separated into five different fractions using a Polar Amino Cyano (PAC) column. Analysis of the fractions indicated that increasing coal concentration from 3.7 to 23.9 wt% results in an increase in the amount of polar materials and a subsequent decrease in the amount of saturated compounds. The wt% of monoaromatics and polyaromatics was not affected by the amount of coal present in the slurry feed. The number and weight average molecular weights of the distillates boiling between 205 °C–525 °C and their hydrocarbon-type fractions decreased as the coal concentration increased. Each hydrocarbon-type fraction was analysed by 1H n.m.r. and f.i.m.s. to determine the effect of coal concentration on compound-type distribution. The results show that increasing coal concentration has a significant effect on compound-type distribution and, in part, coal may enhance the upgrading of bitumen. Based on preliminary isotopic mass balance measurements that take advantage of the difference between the 13C 12C ratio of coal and bitumen, the amount of coal-derived carbon in the coprocessing distillate was estimated.