Pore-Scale Analysis of Green Solvents for Solvent-Based Bitumen Recovery

Bitumen is a critical resource for materials and energy, but its high viscosity requires energy-intensive recovery methods with significant environmental impacts. While CO2 emissions per barrel from oil sands have decreased by 30% over two decades, further innovations are needed for sustainable extraction. We studied green solvents derived from biomass as an environmentally friendly alternative to hydrocarbons in solvent-assisted bitumen recovery. Using Hansen solubility parameters, we optimized binary solvent mixtures to enhance the solubility and minimize viscosity. A novel high-pressure microfluidic device was used to simulate reservoir conditions, verify predictions based on Hansen solubility, and evaluate recovery performance, while dynamic light scattering and elemental analyses revealed the effect of solvent composition on bitumen precipitation and solubility. In toluene/furfural and toluene/guaiacol mixtures, the particle size of dispersed species was larger than that in toluene/ethyl acetate. Moreover, heptane/ethyl acetate caused a higher precipitation of the aromatic fractions. These findings advance the understanding of green solvents for reducing the carbon footprint of bitumen recovery technologies.