Petroleum Diesel-Assisted Ambient Temperature Aqueous-Nonaqueous Hybrid Bitumen Extraction Process

Abstract

Solvents are used in the oil sands industry to reduce the viscosity of bitumen and hence to assist recovery of bitumen prior to its upgrading. Solvents can also be added to the ores to reduce energy consumption during the aqueous-nonaqueous hybrid bitumen extraction process at ambient conditions. The interfacial tension and zeta potential of petroleum diesel in water were measured to confirm the presence of surface active chemicals in petroleum diesel. Functional groups of the surface active species were found to be present in petroleum diesel using fourier transform infrared spectroscopy and gas chromatography mass spectrometry techniques. The characterization techniques confirmed the presence of aliphatic compounds and aromatic compounds in the petroleum diesel, which make petroleum diesel an effective solvent as process aids for bitumen extraction from oil sands ores. Different ores were used at various petroleum diesel dosages to evaluate the performance/efficiency of petroleum diesel on bitumen extraction process from the selected types of ores. The overall extraction performance of selected ores was improved as more petroleum diesel was added to the ores prior to the batch extraction process. The addition of petroleum diesel led to higher initial rates of bitumen liberation and decreased induction time for bitumen and air bubble attachment. The results showed that the optimum addition of petroleum diesel is approximately 10% by mass of bitumen in ore. Dodecane was used as a model solvent to estimate the loss of petroleum diesel to tailings using thermogravimetric analysis techniques. The solvent loss was found to meet the specification of 4 barrels of solvent per 1000 barrels of bitumen produced. Both petroleum diesel and dodecane showed similar impact on bitumen extraction from oil sands ores. The bitumen liberation analysis showed that the reduction of bitumen viscosity is the main factor for improving bitumen recovery in the aqueous-nonaqueous hybrid bitumen extraction process. The similar performance between petroleum diesel and dodecane indicates that the natural surfactants of petroleum diesel did not play a strong role in improving the bitumen extraction from oil sands ores. The reduction in viscosity of bitumen facilitates the migration of bitumen natural surfactants to the interface as shown by lower interfacial tensions between bitumen and water, which play a strong role in bitumen liberation process.