The economic recovery and utilization of heavy hydrocarbons, including bitumen, is one of the world's toughest energy challenges. The demand for heavy crudes such as those extracted from oil sands has increased significantly in order to replace the dwindling reserves of conventional crude. These heavy hydrocarbons, however, are typically located in geographical regions far removed from existing refineries. Consequently, the heavy hydrocarbons are often transported via pipelines to the refineries. In order to transport the heavy crudes in pipelines they must meet pipeline quality specifications.
The extraction of bitumen from mined oil sands involves the liberation and separation of the bitumen from the associated sands in a form that is suitable for further processing to produce a marketable product. Among several processes for bitumen extraction, the Clark Hot Water Extraction (CHWE) process represents an exemplary well-developed commercial recovery technique. In the CHWE process, mined oil sands are mixed with hot water to create slurry suitable for extraction as bitumen froth.
After extraction, the heavy oil slurry (e.g. bitumen froth) may be subjected to a paraffinic froth treatment process. In such a process, the slurry or froth may be introduced into a froth separation unit (FSU) wherein the froth is separated into a diluted bitumen stream and a tailings stream. The diluted bitumen stream may be directed to a solvent recovery unit (SRU) for flashing or other processing to produce a hot bitumen product stream and a solvent stream. The hot bitumen product stream may be sent to a pipeline for production and the solvent stream may be recycled in the treatment process.
Electrostatic desalters/dehydrators have been utilized in the oil field and at refineries for the purpose of removing contaminants in the oil being processed. This generally results in reduced corrosion and fouling, control of trace metal content, and improved wastewater treatment. See, e.g. SAMS, GARY W. AND WARREN, KENNETH W., New Methods of Application of Electrostatic Fields, AIChE Spring National Meeting, New Orleans, La., April 2004. Such units may be used in a variety of configurations. See, e.g. U.S. Pat. No. 6,860,979. Electrostatic desalters may also be used to treat heavy oils. See, e.g. THOMASON, WILLIAM H., ET AL, Advanced Electrostatic Technologies for Dehydration of Heavy Oils, SPE 97786, November 2005.
Methods to optimize the efficiency of settlers can significantly impact the efficiency of heavy hydrocarbon (e.g. bitumen) recovery processes. There exists a need in the art for a low cost method to produce pipeline quality hydrocarbons from heavy oil or bitumen.