Turning crude oil into useful fuels like gasoline, diesel, and heating oil currently requires a lot of energy.
In fact, this process—called fractionation—accounts for about 6% of the world’s carbon dioxide emissions.
That’s because the method used today involves heating oil to high temperatures to separate its components by their boiling points.
Now, engineers at MIT have come up with a cleaner, more efficient method that could revolutionize the way oil is refined.
Instead of relying on heat, their new technique uses a special membrane that filters oil components based on the size and shape of their molecules. This could dramatically cut down the energy needed for refining and, in turn, reduce carbon emissions.
Professor Zachary Smith, who led the research, describes it as a totally new way of thinking about oil separation.
Rather than boiling the mixture, they use ultra-thin filters to sort the different components.
These filters can separate even the tiniest molecules with incredible precision, and they don’t swell or break down when exposed to crude oil—an issue that has plagued earlier attempts.
The team’s findings, published in Science, show promise for large-scale use because the new membrane can be made using an industrial technique already used in water desalination.
In that process, called interfacial polymerization, a thin film forms between two liquids—water and an organic solvent. Chemicals from each liquid meet at the border and react, creating a strong membrane.
While this method works well for turning seawater into drinking water, the traditional membrane it produces (made of a material called polyamide) isn’t suitable for separating crude oil components. It absorbs too much oil, swells up, and loses its ability to sort molecules by size.
To fix this, the researchers made a few clever tweaks. First, they changed the chemical bond holding the membrane together—from an amide bond to an imine bond.
This new bond is tougher and repels oil, preventing swelling. Then, they added a molecule called triptycene that helps the membrane form tiny pores that are just the right size to filter oil molecules.
In tests, the new membrane successfully separated light and heavy parts of oil mixtures, such as naphtha, kerosene, and diesel. In one case, it increased the concentration of a chemical called toluene by 20 times compared to its original amount. This suggests that using a series of these membranes could replace parts of traditional oil refining processes—cutting emissions and saving energy.
What makes this discovery even more promising is that the manufacturing method is already well known and widely used in the water industry. The researchers believe it will be relatively easy to adapt existing production lines to create these new oil-filtering membranes on a large scale.
If widely adopted, this new technology could transform oil refining from one of the world’s most energy-hungry processes into a cleaner, more efficient operation.
Source: MIT.
