Firms explore greener ethylene

Chemical companies are ramping up efforts to untangle one of the knottiest problems in industrial chemistry: an environmentally friendlier route to ethylene.

Dow and Shell have teamed up to advance electric cracking. And the start-up EcoCatalytic says it has scaled up a pilot unit that uses oxidative dehydrogenation to convert ethane into ethylene.

The conventional steam-cracking method of making petrochemicals is highly energy intensive. Hydrocarbon-fueled furnaces are heated to more than 800 °C, a temperature necessary to convert alkanes such as ethane into alkenes like ethylene, one of the building blocks of petrochemicals.

At Dow and Shell, work is already underway to develop an ethylene cracker that uses heat from electricity instead of combustion. Such a setup could save CO₂ emissions if the electrical grid is powered by renewable energy.

“This new work with Dow has the potential to contribute to the reduction of carbon emissions from the manufacture of chemicals,” Thomas Casparie, executive vice president of Shell’s chemical business, says in a statement.

BASF has been working with the engineering firm Linde on technology to electrify its crackers. The German chemical company says switching to electric power could cut cracker CO₂ emissions by 90%.

And a Finnish start-up, Coolbrook, is developing a process that uses high-speed rotors powered by electricity to generate the heat needed to crack the feedstock.

An industry consultant, who asked not to be named, questions the electricity consumption of a large chemical plant. “You might need an entire fleet of wind turbines to power an ethylene cracker,” he says.

Woburn, Massachusetts–based EcoCatalytic contends that its oxidative process can fetch CO₂ emission savings of 80%. In it, a metal oxide transfer agent provides for the conversion of ethane into ethylene and water. The transfer agent is then reoxidized with air.

Company founder John A. Sofranko compares the process to hemoglobin in respiration but at “much higher temperature and much larger scale.”

EcoCatalytic has received a $2 million grant from the US Department of Energy. Southwest Research Institute built and operates the pilot plant, which is in San Antonio, Texas.