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 asphaltene-containing oils (e.g., heavy oil and bitumen) from mined oil sands involves the liberation and separation of 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 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. The diluted bitumen stream is an asphaltene-containing oil and very often is a “near-incompatible” oil.
A “near-incompatible” oil is an oil that is close to the conditions (e.g., composition, temperature, pressure, etc.) for precipitating asphaltenes. Asphaltene precipitation results in the deposition of organic solids, such as foulant and coke, on equipment such as refinery process equipment that contact the oil. Even small amounts of foulant or coke on such equipment results in large energy loss because of much poorer heat transfer through the foulant and coke as opposed to metal walls alone. Moderate amounts of foulant and coke cause high pressure drops and interfere with and make process equipment operation inefficient. Significant amounts of foulant or coke may plug up process equipment to prevent flow or otherwise make operation intolerable, requiring the equipment to be shut down and cleaned.
U.S. Pat. No. 5,871,634 discloses a method for blending potentially incompatible petroleum oils. The method includes determining insolubility numbers for the separate oils and a solubility blending number for the mixed oils and calculating a ratio of oils to produce a compatible mixture. U.S. Pat. No. 5,997,723 discloses a similar method for blending near or potentially incompatible petroleum oils.
Asphaltene precipitation leads to fouling of equipment in heavy oil recovery processes, which significantly impact the efficiency of such heavy hydrocarbon (e.g., bitumen) recovery processes. As such, there exists a need in the art for efficient, low cost methods and systems to produce pipeline specification bitumen that do not foul the process equipment. In particular, methods and systems that efficiently generate compatible oil streams during heavy hydrocarbon recovery processes are needed.
USPTO Backgrounds
USPTO Backgrounds