A domestic research team has developed a membrane separation technology that filters crude oil at room temperature without boiling it at high heat. The result shows potential to supplement or partly replace the distillation process that has served as the refining industry's basic method for more than 100 years.
The Ministry of Science and ICT said on the 25th that a research team led by Professor Ko Dong-yeon in the Department of Chemical and Biomolecular Engineering at KAIST succeeded in precisely separating components in crude oil at room temperature using an inexpensive polymer membrane. The study was published the same day in the international journal "Nature."
Current refining processes largely rely on distillation, which heats crude oil to more than 350 degrees and uses differences in boiling points to separate it into gasoline, kerosene and diesel. It is effective but has limits in that it uses a large amount of energy and emits a lot of carbon dioxide.
The team tried passing crude oil through a membrane instead of boiling it. A membrane is a filter with very small pores. Until now, the prevailing view was that to precisely distinguish differences in molecular size, a separate thin functional layer had to be applied to the membrane surface. But creating a selective layer and coating it uniformly is expensive and becomes more prone to defects as production scales up to large areas.
In this study, the researchers used a porous polymer film without a separate coating. They flowed crude oil directly through a membrane made of polyacrylonitrile (PAN). Then, heavy components in the crude oil adhered to the membrane's tiny pores and spontaneously formed even smaller pathways of 2 nanometers (nm, one-billionth of a meter) or less.
Generally, the phenomenon of oil components sticking to a membrane is regarded as fouling that degrades performance, but the team used this effect in reverse. As crude oil passed through the membrane, it formed a more precise sieve on its own, and as a result, light naphtha, gasoline and kerosene components passed quickly while heavy components were effectively filtered.
The newly developed method achieved a separation rate more than 23 times faster than previously reported crude-oil membranes, and it showed almost no performance decline even after 28 days of use. It could be applied by adding a filter module to piping without replacing entire existing refining facilities.
Analysis showed that if crude oil is first passed through the membrane and only the remaining components are processed in a conventional distillation column, energy use can be cut by 31.6%, carbon dioxide emissions by 37.6% and operating costs by 36%. The team sees the technology expanding beyond refining to a range of chemical processes, including purification of pyrolysis oil from waste plastics, battery solvent recovery and pharmaceutical purification.
Professor Ko Dong-yeon said, "Thanks to close collaboration with HD Hyundai Oilbank, which supplied actual crude oil, we were able to validate the technology to a level aligned with industrial reality." Co-corresponding author Professor Lee Jae-woo of KAIST said, "We will continue research to advance large-area modularization and long-term operation technologies so they can be applied to real industrial processes."
References
Nature (2026), DOI: https://doi.org/10.1038/s41586-026-10677-3