Production of bitumen-derived hydrocarbon liquids from Utah's tar sands

reportIn previous work done on Utah's tar sands, it had been shown that the fluidized-bed pyrolysis of the sands to produce a bitumen-derived hydrocarbon liquid was feasible. The research and development work conducted in the small-scale equipment utilized as feed a number of samples from the various tar sand deposits of Utah and elsewhere. The results obtained from these studies in yields and quality of products and the operating experience gained strongly suggested that larger scale operation was in order to advance this technology. Accordingly, funding was obtained from the State of Utah through Mineral Leasing Funds administered by the College of Mines and Earth Sciences of the University of Utah to design and build a 4-1/2 inch diameter fluidized-bed pilot plant reactor with the necessary feeding and recovery equipment. The current United States Department of Energy contract supplied the funds to test and operate the unit. This report covers the calibration and testing studies carried out on this equipment. The tests conducted with the Circle Cliffs tar sand ore gave good results. The equipment was found to operate as expected with this lean tar sand (less than 5% bitumen saturation). The hydrocarbon liquid yield with the Circle Cliffs tar sand was found to be greater in the pilot plant than it was in the small unit at comparable conditions. Following this work, the program called for an extensive run to be carried out on tar sands obtained from a large representative tar sand deposit to produce barrel quantities of liquid product. For the extended run, a moderately high grade ore from Whiterocks was obtained. Operation with this grade of tar sand (8-11%) bitumen presented many difficulties, including significant problems with ore preparation, ore feeding, and product recovery. The problems encountered and solutions devised are described in the report in detail. The unit w as made operable and many days of operation were accomplished. Approximately one barrel of product was made and extensively evaluated. The overall material balance from the operation was excellent, and yields of liquid product in excess of 55 wt % of the bitumen fed to the unit were obtained. The API gravity was increased and weight percent of the product boiling below residuum temperatures was 87.5%, as compared with only 25.4% for the native bitumen. The experience obtained with these studies has provided sufficient data to justify further development of the fluidized-bed concept for tar sand processing. We feel very confident that with further upgrading of the unit, it will be ready for around-the-clock operation with Utah's tar sands with excellent results