"This is a whole new way of envisioning a separation process," says Zachary P. Smith, an associate professor of chemical engineering at MIT. He highlights the potential of separating components based on shape and size rather than boiling them.
In a groundbreaking development, MIT engineers in the USA have created a membrane capable of filtering crude oil components by molecular size. This innovation, revealed in Science, promises a significant reduction in the energy-intensive process of crude oil fractionation, which currently accounts for about 6% of global CO2 emissions.
The new membrane efficiently separates heavy and light oil components and resists swelling, a common issue with other oil separation membranes. Made as a thin film, it can be manufactured using existing industrial techniques, paving the way for widespread adoption.
Conventional heat-driven oil fractionation consumes about 1% of global energy. Using membranes could slash energy consumption by an estimated 90%. The MIT team modified polymers used in reverse osmosis water desalination to achieve this, adapting them for hydrocarbon separation.
The modified membrane uses an imine bond, more rigid and hydrophobic than the amide bond in water desalination membranes. This allows hydrocarbons to pass through quickly without causing swelling. The introduction of triptycene further refines the pore size for hydrocarbon passage.
Andrew Livingston, a professor of chemical engineering at Queen Mary University of London, calls this "an important step toward reducing industrial energy consumption." He emphasizes its innovative application of interfacial polymerization to hydrocarbon feedstocks.
In tests, the membrane achieved a 20-fold increase in toluene concentration compared to the original mixture. It also efficiently separated naphtha, kerosene, and diesel by molecular size. Researchers envision a cascade of these filters to purify complex mixtures and isolate desired chemicals.
Taehoon Lee, a former MIT postdoc, notes that interfacial polymerization is already used for water desalination membranes. This makes adapting existing manufacturing lines for mass production feasible, potentially revolutionizing crude oil processing.