Scientists from oil giant ExxonMobil and the Georgia Institute of Technology in the US have developed a potential breakthrough in reducing the amount of energy and emissions associated with manufacturing plastics.
Results of the research were published in the peer-reviewed journal Science, and ExxonMobil said that if brought to an industrial scale the new technology could slash industry's global annual carbon dioxide emissions by up to 45 million tonnes, or the equivalent of around five million households.
It could also cut the cost of making plastics worldwide by up to $2bn (€1.77bn) a year.
Using a molecular-level filter, the new process employs a form of reverse osmosis to separate para-xylene, a chemical building block for polyester and plastics, from complex hydrocarbon mixtures. The current commercial-scale process used around the world relies on energy and heat to separate those molecules.
Vijay Swarup, vice president of research and development at ExxonMobil Research and Engineering Company , said: “Through collaboration with strong academic institutions like Georgia Tech, we are constantly exploring new, more efficient ways to produce the energy, chemicals, and other products consumers around the world rely on every day.
“If advanced to commercial-scale application, this technology could significantly reduce the amount of greenhouse gas emissions associated with chemical manufacturing.”
ExxonMobil said the research “successfully demonstrated that para-xylene can be separated from like chemical compounds known as aromatics by pressing them through a membrane that acts as a high-tech sieve, similar to a filter with microscopic holes”.
Commercially practiced separations involve energy-intensive crystallisation or adsorption with distillation. Globally, the amount of energy used in conventional separation processes for aromatics is equal to about 20 average-sized power stations.
Initially the ExxonMobil and Georgia Tech team developed a new carbon-based membrane that can separate molecules as small as a nanometer. The membrane was then incorporated into a new organic solvent reverse osmosis process, during which aromatics were pressed through the membrane, separating out para-xylene.
"In effect, we'd be using a filter with microscopic holes to do what an enormous amount of heat and energy currently do in a chemical process similar to that found in oil refining,” said Mike Kerby, corporate strategic research manager at ExxonMobil.
Researchers said the carbon-based membrane was about 50 times more energy efficient than the current state-of-the-art membrane separation technology. Because the new membrane is made from a commercially-available polymer, ExxonMobil said it believed it had the potential for commercialisation and integration into industrial chemical separation processes.