Plastic production in the United States is surging due to an abundance of cheap natural gas — which contains the building block of plastic — and a friendly regulatory environment in Washington.
Amid growing concerns about the environmental effects of ethylene production facilities like Beaver County’s Shell Pennsylvania Petrochemicals Complex, researchers at the University of Pittsburgh Swanson School of Engineering, about 35 miles southeast of the cracker plant, may have found a way to make plastic production leaner and cleaner.
Speaking with NEXTpittsburgh, Karl Johnson, W.K. Whiteford Professor in Pitt’s Department of Chemical and Petroleum Engineering, explains that the foundation of many types of plastic is ethylene, an organic compound that can be made from ethane gas.
“Ethane is very cheap and not very useful, but ethylene is very useful,” Johnson says.
Under current engineering systems, like the one going up in Beaver County, the molecules are separated via a complex process of cooling, liquefying, pressurizing and distilling natural gas.
“It not only takes time,” Johnson says. “It takes a lot of energy and it takes a lot of money to sort molecules.”
In a paper published in the Journal of the American Chemical Society in August, Johnson and co-authors Götz Veser from the Department of Chemical and Petroleum Engineering, and Nathaniel Rosi from the Department of Chemistry present research detailing a new system that could separate ethylene in a fraction of the time, labor and energy used in traditional systems.
Their process relies on a chamber containing a porous, crystal filter specially designed to have holes nearly the same size as the molecules. Within these pores are copper atoms that naturally bind to ethylene while allowing the ethane to pass through.
The result is significantly purer ethylene at a fraction of the cost, both financial and environmental, Johnson says. “If it were to work, you could separate this mixture with much less energy; you would produce much less CO2.”
While he’s optimistic about the potential of their work, Johnson is quick to emphasize that much more research will be needed before their technology shows up in Beaver County. “This is very basic research,” he says. “I’m not even sure this will absolutely work on an industrial scale.”
To date, Johnson has had no contact with Royal Dutch Shell about applying the research to the Beaver plant.
Still, he’s cautiously optimistic that their ongoing research, funded by the U.S. Department of Energy, could have a positive impact on the plastics industry.
“In future years,” he says, “this might be a viable thing.”