CANMET coprocessing of low-rank Canadian coals

An extensive research program is underway at CANMET on the simultaneous liquefaction of coal and upgrading of heavy oil or petroleum residues. CANMET coprocessing is a single-stage once-through process that utilizes an inexpensive disposable catalyst. It can be viewed as an extension of the CANMET hydrocracking process with high coal concentration in the slurry feed. The feasibility of CANMET coprocessing was tested for a number of coals and residues to assess their suitability as coprocessing feedstocks and to generate a database of the product yield structure for each coal. The process performance using different feedstocks is compared. Using Cold Lake vacuum bottoms as a coprocessing medium, eight coal feedstocks were investigated. The process was feasible for all the coals with marginal variations, among the low rank coals, in the distillate yields and qualities and in the coal conversions. Similarly, using an Alberta subbituminous coal, the process was shown to be feasible for the residues tested. It was found that the residues originating from bitumens/heavy oils result in higher pitch conversions and higher distillate yields than those originating from conventional crudes. The distillates produced from conventional crude residues, however, are of a better quality than those produced from bitumen/heavy oil residues.