Crude oil fractionation by heat-based distillation is an energy-intensive, carbon-emitting process that accounts for nearly 1% of the world’s energy use. New polymer membrane technology developed by researchers from Georgia Institute of Technology, Imperial College London and ExxonMobil could be deployed to reduce both emissions and energy usage compared to traditional refining processes.

The new low-energy membranes might be substituted for certain steps in the distillation process to allow A molecular model of the polymer membrane, with the pores shown in blue. Source: Imperial College Londonimplementation of a less energy-intensive hybrid refining system. The spirocyclic polymer formulated by the researchers was applied to a robust substrate to form membranes able to separate complex hydrocarbon mixtures through the application of pressure rather than heat. The 200 nm thick films were incorporated into membrane modules using a roll-to-roll process, and the resulting glassy, microporous materials were demonstrated to fractionate light crude oil through a combination of class- and size-based sorting of molecules.

The new membrane proved effective at recovering gasoline and jet fuel from crude oil samples. The polymers were used to separate light shale crude oil and succeeded in fractionation of molecular weights of about 170 daltons. The scalable, selective membranes offer potential for the hybridization of energy-efficient technology with conventional processes such as distillation.