Energy & Fuels, Vol.34, No.10, 12757-12770, 2020
Modeling Greenhouse Gas Emissions from Oil Sands Partial Upgrading Technologies Using a Life Cycle-Based Model
As the Canadian oil sands industry continues to evolve, so do challenges associated with the industry's greenhouse gas (GHG) emissions. In recent years, the industry has turned its attention to the development of partial upgrading technologies that reduce the viscosity of oil sands bitumen so it can flow through pipelines without adding diluent or as much diluent (a thinning agent). Partial upgrading offers the potential to avoid the high capital costs of adding new full upgrading capacity and the high and volatile costs of diluent. However, the GHG emissions performance of the majority of these new technologies is unknown. We report enhancements to the Oil Sands Technologies for Upgrading Model (OSTUM 3.0), a model that estimates GHG emissions intensities of upgrading technologies, enabling the evaluation and comparison of full and partial upgrading technologies. We develop new modules to estimate the direct and indirect GHG intensities of two technologies: MEG Energy's HI-Q Process (representative of thermal cracking and solvent deasphalting) and ENI's Slurry Technology (EST) (representative of slurry-phase hydroconversion). The HI-Q base, low, and high scenario GHG intensities are 3.7, 2.3, and 6.4 grams of carbon dioxide equivalent per megajoule of partially upgraded bitumen (g CO(2)e/MJ PUB, or 20.4, 12.7, and 35.3 kg CO(2)e/barrel of bitumen feed), respectively, and are 8.3, 6.6, and 12.3 g CO(2)e/MJ PUB (or 51.8, 40.9 and 76.5 kg CO(2)e/barrel of bitumen) for EST. The GHG intensities are not directly comparable as EST produces a higher quality and bottomless PUB (26.8 degrees API, 1.6 wt % S vs 19.1 degrees API, 3.7 wt % S). Our analysis found that product yields, product quality, GHG intensities, and emission sources can vary considerably between partial upgrading technologies. OSTUM 3.0 is a tool that can help technology developers, researchers, and policymakers better understand the GHG performance of these emerging technologies.