Professor Dong-Yeun Koh’s research team at KAIST have developed a next-generation polymer membrane that can separate crude oil at room temperature without boiling, offering a potential alternative to distillation, the dominant refining process for more than a century.

 KAIST research team have developed a next-generation polymer membrane technology that could significantly reduce the energy use and carbon emissions of crude oil refining. The study addresses a major limitation of conventional refining, which has relied for more than a century on distillation, a highly energy-intensive process that separates crude oil by heating it to temperatures above 350°C and then cooling it. Globally, refineries consume about 1,100 TWh of energy each year through distillation, while Korea’s refining and petrochemical industries also contribute substantially to national greenhouse gas emissions.

The research team, led by Professor Dong-Yeun Koh proposed a new membrane-based approach that can separate crude oil at room temperature without boiling. Until now, precise molecular separation was generally believed to require a thin selective layer on the membrane surface. However, such layers increase manufacturing complexity, raise costs, and are prone to defects during large-area scale-up.

In contrast, the team used a porous polyacrylonitrile (PAN) membrane without any additional selective coating. PAN is a durable and chemically stable polymer widely used in industrial membranes. When crude oil passed through the PAN membrane, heavy hydrocarbon components selectively adsorbed onto the pore walls inside the membrane. This naturally narrowed the pores and spontaneously formed separation channels smaller than 2 nanometers, roughly one-fifty-thousandth the width of a human hair.

This self-formed nanostructure allowed lighter components such as naphtha, gasoline and kerosene to pass through rapidly, while heavier fractions were effectively blocked. Notably, what is usually considered fouling—the accumulation of oily components on membrane surfaces—was instead used as a functional mechanism to create precise separation pathways.

 The membrane achieved a crude oil separation rate about 23 times faster than the best previously reported membrane performance and operated stably for 28 consecutive days without performance loss. Because the technology can be installed as filter modules in existing refinery pipeline systems, it may be implemented without large-scale replacement of current facilities.

Process simulations showed that combining the PAN membrane with conventional distillation could reduce energy consumption by 31.6%, carbon dioxide emissions by 37.6%, and operating costs by 36%. The researchers estimate that applying this technology across Korea’s refining and petrochemical industries could reduce greenhouse gas emissions by about 10 million tons annually, comparable to the yearly emissions of approximately 4 million passenger cars.

Beyond crude oil refining, the technology may also be applied to waste plastic pyrolysis oil upgrading, battery solvent recovery, pharmaceutical purification, and other precision chemical separation processes. The study was published online in Nature on June 25.

※ Paper Name : Crude Oil Fractionation by Means of Mesoporous Polyacrylonitrile Membranes . DOI 10.1038/s41586-026-10677-3
Figure Reference : https://www.nature.com/articles/s41586-026-10677-3