The development of life cycle greenhouse gas emission footprints of novel pathways for the solvent-assisted and solvent-electromagnetic heating oil sands extraction processes

Abstract

Steam-based oil sands extraction methods are emissions-intensive. Solvent-assisted and solvent-electromagnetic heating are alternative methods with the potential to lower greenhouse gas emissions (GHG). However, identifying an energy-efficient process pathway for these technologies remains a major concern. This is a gap in the research. In this study, we developed simulation models to assess the performance of solvent-assisted, solvent-electromagnetic heating, and steam-assisted oil sands extraction central processing facilities. Three central processing facilities (pathways) were developed for solvent-assisted and solvent-electromagnetic heating processes to recover bitumen and solvent from emulsions. Pathways I and III use a low-temperature and a high-temperature distillation system, respectively, to purify the solvent. Pathway II uses a high-pressure separator to lower the amount of non-condensable gases in the solvent. Each pathway was applied to a deep and a shallow reservoir. Sensitivity and uncertainty analyses were conducted to present the GHG emission results. The results show that pathways I and III produce satisfactory solvent purity and minimize solvent losses in the central processing facility, and pathway II does not. Pathway II can be applied when a high degree of purity is not required. The life cycle GHG emissions from pathways I and II may not be favorable to the solvent-assisted process if the electricity emission factor and solvent-to-oil ratio are high. The lowest GHG emissions are from pathway III. The life cycle GHG emissions of the solvent-electromagnetic heating extraction in pathway III range from 34.4 to 61.7 and 23.3 to 43.9 kgCO2e/b-e for the deep and shallow reservoirs, respectively, while solvent-assisted emissions range from 26.6 to 48.2 and 20.2 to 40.0 kgCO2e/b-e for the deep and shallow reservoirs, respectively. Steam-assisted gravity drainage emissions range from 72.7 to 111.6 kgCO2e/b. The results show that solvent-assisted and solvent-electromagnetic heating processes can provide better performance than steam-assisted gravity drainage when a high-temperature distillation is installed in the central processing facility to recycle the solvent.