Recycle Oil Pyrolysis and Extraction of Tar Sand

Western Research Institute is developing a new pyrolysis process called ROPE© (Recycle Oil Pyrolysis and Extraction) for recovering products from tar sands that require a minimum of upgrading to produce finished, marketable fuels or that can be used as a diluent to decrease the pour point of bitumen for transportation. The concept consists of two pyrolysis steps: (1) retorting tar sand at a lower temperature (T < 420°C) with the bitumen and product oil; and (2) completing the pyrolysis of the residue at a higher temperature (T > 420°C) in the absence of product oil recycle. Three tar sand resources, Asphalt Ridge (Utah), Sunnyside (Utah), and Athabasca (Alberta), have been investigated using a two-inch-diameter process development unit (PDU). Experimental results from three tar sands indicate that oil yields from the ROPE© process will be greater than those from conventional pyrolysis processes. The product oils produced from each of the resources have been evaluated using selected analytical techniques. Differences were observed in the characteristics of the distillable liquid products from the three resources. These differences are discussed in relation to the potential end uses of the products. Depending upon the characteristics, unleaded gasoline blending stocks, diesel fuels, and aviation fuels can be produced. INTRODUCTION A major obstacle to commercialization of U.S. tar sand is the high cost associated with the mining and processing of the tar sand and bitumen. In order to reduce the financial risks and encourage tar sand commercialization, new processing technologies must be developed. These technologies should produce greater oil yield and a product that requires a minimum of upgrading to produce a marketable product Recent preliminary data (Cha e t al., 1986 and 1987) from the ROPE© (Recycle Oil Pyrolysis and Extraction ) concept suggest that processing tar sand with product oil recycling may achieve these results. It is in the best interests of the energy industry to explore the potential of this concept to develop a tar sand industry. The overall objective of this research has been to develop a process that (1) produces greater oil yields than the other pyrolysis processes, (2) produces an upgraded feedstock, (3) produces products that can be used as a diluent to decrease the pour point of bitumen for transportation, and (4) can be used as a solvent for extraction processes. The ROPE© concept consists of two pyrolysis steps: (1) retorting the tar sand at a lower temperature (T < 420^) with the bitumen and product oil; and (2) completing the pyrolysis of residue at a higher temperature (T > 420°Q in the absence of product oil recycle. Three tar sand resources, Asphalt Ridge (Utah), Sunnyside (Utah), and Athabasca (Alberta), have been investigated using a two-inch-diameter process development unit (PDU). A summary of these investigations is provided in this report EXPERIMENTAL APPARATUS AND PROCEDURE Screw Pyrolysis Reactor System (Process Development Unit, PDU) A two-inch-diameter screw pyrolysis reactor (SPR) system was constructed to provide a continuous retorting system for tar sand (Figure 1). The SPR system consists six subsystems: horizontal screw pyrolysis reactor (HSPR); inclined screw pyrolysis reactor (ISPR); feeder; heavy oil tank and pump; reflux condensers and flasks; and solids collection tank. The HSPR has a 1.5-inch-diameter screw enclosed in a two-inch-diameter casing 104 inches long. It is equipped with three separately controlled heaters and three condensers and condensate collection pots, one for each zone. The ISPR also has a 1.5-inch-diameter screw enclosed in a two-inch-diameter casing 96 inches long. It is equipped © Copyright 1987 Western Research Institute