Multiphysics Approach to Developing a New Heavy Oil Upgrading Technology

Continuous increases in the sulfur content and average molecular weight of remaining petroleum reserves are straining refinery capacity using current technologies.  New technologies are required for cleaner, energy efficient utilization of sulfur rich heavy oils.   Treating heavy oils and bitumen in supercritical water has been known since the 1980s to reduce their molecular weight distributions and sulfur contents.  Crucially, supercritical water treatment does not promote coke formation, does not require catalysts, and reduces heavy oil asphaltene content.  However, commercialization has been held back by contradictory literature data and a lack of fundamental understanding of the chemical reactivity, thermodynamic phase behavior, and transport phenomena at supercritical conditions.  This paper will present an overview of an on-going research effort to provide a deeper fundamental engineering understanding of the relevant physical and chemical processes.  Experimental work has been performed on model systems to measure global rate constants, close material balances, and identify decomposition products.  Catalysts have been deployed to help understand chemical mechanisms and evaluate the potential of catalytic enhancement of the supercritical water process.  Computational work has utilized these experimental data to construct extensive reaction networks that elucidate the role of water, the water gas shift reaction, and primary reaction pathways.  Transport and thermodynamic simulations provide understanding of the relevant heat, mass, and momentum time scales and how they interact with the complex, multi-component, near-critical thermodynamic phase behavior and relevant chemical time scales.