Yale scientists have developed a new process that could turn discarded plastic water bottles into jet fuel, offering a breakthrough in recycling and sustainable aviation.
Yale University researchers have figured out how to convert plastic waste into “fuel-range chemicals” that could eventually power turbines and diesel engines and jets. Once refined, these “fuel-range hydrocarbons,” a building block, will become the final product jet and diesel fuel. The process could help reduce plastic pollution and provide a ready supply of fuel, the researchers said.
What makes the scientists’ findings groundbreaking is that the process can be scaled up and made commercially viable since it does not use catalysts, but relies on controlled intense heat, they said. “You have an increasing amount of plastic and you have an increasing demand on jet fuels, right?” said Yale scientists Liangbing Hu, who co-founded, Polymer-X Inc., a “climate technology” start-up, to attract investors.
Through Polymer-X, Liangbing Hu said their plan is to transition it from the university lab to the marketplace and are working with other companies and funding agencies to further test the technology. Jet fuel is the goal, as air travel will keep increasing. A battery-powered electric plane may not become a viable option in the near future because the battery would need to be as large as the plane, Liangbing Hu noted.
“For an airplane, you will actually have to rely on fuel,” he said. “Especially for long-range planes, like if you go to Europe, you cannot have a battery-powered plane.” Liangbing Hu’s New Haven lab was the research hub. He is a professor of electrical and computer engineering and material science and is also director of Center for Materials Innovation, a research center at the university.
The team also included Shu Hu, a Yale assistant professor of chemical and environmental engineering, Qi “Tony” Dong, president and co-founder of Polymer-X, who is now an assistant professor at Purdue University. Dong and Liangbing Hu said they are aiming to develop a commercial product in five to 10 years. The startup is “leading the R&D effort based on the technology reported in this study,” said Dong, who was a lead author on it.
Through repeated testing and proving the concept, Dong said their hope is to “lower the barrier, build the confidence, so big companies can work with us and take it from there to the next step.” Their long-term plan is for larger companies to “scale it up into many, many tons to have a real impact,” Dong said.
The United Nations Environment Programme estimates the equivalent of 2,000 garbage trucks full of plastic are dumped into oceans, rivers and lakes daily, with 19 million to 23 million tons leaching into aquatic ecosystems. The researchers found the best and least expensive method to turn plastic into fuel is to use electricity to create intense heat up to 1,650 degrees in place of costly catalysts to cut the molecular structures in a process called “electrified pyrolysis”.
“Jet fuel is a shorter version of the plastic after cutting,” Liangbing Hu said. “You basically cut them into shorter segments. Typically, what people do in the past is that they use expensive catalysts to cut them.” Dong said they can cut the plastic by increasing and decreasing the temperature in a reactor. The heat functions “almost like a scissors to cut the long polymer plastic chain into small fuel chains,” he added.
“Instead of trying to re-melt it, re-mold it into another shape of using the plastic waste, we convert them into one high-end product,” Liangbing Hu said. “That is the jet fuel.” The heat turns plastic waste, which the scientists said is “basically a long chain of polymers” into a “high-end product” from trash. Through the process, the long chains of plastic molecules are broken down and converted into smaller hydrocarbons, which can be turned into a form of energy that becomes fuel, according to the scientists.
“So we waste only a little bit,” Dong said. “Our reactor is catalyst free, a critical and unique feature in our process.” While others have tried to turn plastic into fuel, their methods typically relied on the use of a “very expensive or unstable catalyst”. This method turns less than 50% of plastic into fuel, while the rest is “wasted,” Liangbing Hu said. The Yale scientists’ approach converts 70% or 80%, he added.
“It’s a big gain in terms of economics,” Liangbing Hu said. “That means about 80% of waste is no longer waste. It’s a useful resource.” The fact that plastic is so inexpensive has made it easy for consumers to discard it without concern, creating a pollution problem, they said. “People use plastic for shopping bags and other items because it’s stable and very cheap,” Dong said.
The heater is powered by electricity, which is becoming a more efficient energy source, Liangbing Hu said. “The cost is actually decreasing to the level that we can widely use the electricity to do the job,” he said.
News Courtesy : New Heaven Register