Lifelong sailor James Holm admits he was literally moved to tears a few years ago when he saw the extent of the plastic pollution on a remote island off the coast of Panama. Now, Holm and chemist Swaminathan Ramesh of EcoFuel Technologies have joined forces to develop a solution to the problem – a mobile technology to transform plastic waste to produce hydrocarbon fuel.
The pair are currently testing a prototype reactor designed by Ramesh in a demonstration project for the government of the city of Santa Cruz, California, they reported at the ACS meeting in San Francisco. They envisage the technology could one day be implemented on the back of trailers on land or placed aboard boats that convert ocean waste plastic floating on the ocean to fuel to power the vessels. Any remaining fuel could then be sold back in port.
Pyrolysis technologies to break down or depolymerise unwanted polymers have been around for years, Ramesh said. But they have generally operated at very high temperatures, generating hydrocarbons that require costly refining steps before the fuel is useable.
‘Previous plastics to fuel conversion technologies have so far involved very large systems, big enough to fill stadiums. They haven’t been practical onboard vessels,’ elaborated Holm, who is executive director of non-profit organisation Clean Oceans International. EcoFuel’s Plastics To Fuel (PTF) reactors, in contrast, are roughly the size and shape of your living room sideboard and convert 100-100,000 pounds of plastic waste to fuel per day.
Polyolefin wastes floating on the ocean can be collected to either gasoline or diesel via a continuous process in 80-90 or 90% yield, respectively, Ramesh noted. For safety reasons aboard vessels, the pair are mainly interested in making diesel fuel because of its higher ignition flash point.
The technology breakthrough has been to use a metallocene catalyst deposited on a porous support material, he explained. The technology is cost effective at small scale, runs at lower temperatures and produces fuels directly without further refining.