Comprehensive study on cleaner production of heavy oil from Athabasca oil sands using chemical additives in biodiesel-assisted ambient-aqueous bitumen extraction process

Abstract

The massive unconventional petroleum resources of Athabasca oil sands in Alberta, Canada are currently being excavated and processed using the hot water bitumen extraction (HWBE) process and steam-assisted gravity drainage (SAGD) technology. A major challenge associated with HWBE process is high energy intensity for maintaining an operation temperature of 40–55 °C. Solvent-assisted ambient aqueous bitumen extraction processes, in which a portion of solvent is added for oil sands pretreatment prior to extraction process, have been reported to be capable of reducing the energy intensity via ambient temperature oil sands extraction operations. However, there is still a gap between the current solvent-assisted process and industrial expectations. This study focuses on optimization of biodiesel-assisted ambient aqueous bitumen extraction, an example of the solvent-assisted process, by incorporating methyl isobutyl carbinol (MIBC) and ethylene oxide-propylene oxide (EO-PO) copolymer in oil sands pretreatment. The idea is to take advantage of such chemicals and demulsifiers used downstream of heavy oil (known as bitumen) extraction process by their addition upfront as in the case of biodiesel-assisted hybrid extraction process. With the incorporation of these chemicals and demulsifiers in the improved biodiesel-assisted process, both bitumen liberation and bitumen flotation efficiency were improved significantly with the addition of biodiesel/MIBC mixture at 10 wt% of bitumen. The results from bench-scale experiments revealed a higher bitumen recovery and a cleaner bitumen froth by the improved biodiesel-assisted process at ambient temperature as compared with the traditional biodiesel-assisted process, as well as current industrial HWBE process, featuring a cleaner production of heavy oil from Athabasca oil sands and other heavy oil resources.