Researchers at Washington State University claim they have created a way to make jet fuel from plastic waste. Landfills in the US take in about 28 million tons of plastic waste each year, according to the EPA. It sits there for centuries, taking up space and making a mockery of the idea that human beings are even a little bit sapiens.
But what if that trash could be made into something useful, like jet fuel? Professor Hanwu Lei and his colleagues say they have done precisely that. “Plastic is hard to break down,” Lei says, according to a report by Science Daily. “You have to add a catalyst to help break the chemical bonds. There is a lot of hydrogen in plastics, which is a key component in fuel.”
That catalyst is activated carbon, which has a larger surface area than ordinary carbon. The researchers take low density polyethylene and mix it with a variety of waste plastic products, like water bottles, milk bottles, and plastic bags. The grind it all up into three millimeter pellets — about the size of a grain of rice.
The plastic granules are then placed on top of the activated carbon in a tube reactor at temperatures ranging from 430 to 571 degrees Celsius. The result is liquid diesel fuel that can then be converted to jet fuel. Since the carbon is a catalyst, it can be recovered at the end of the process and reused.
After testing several different catalysts at different temperatures, the best result they obtained is a mixture of 85% jet fuel and 15% diesel fuel. “Waste plastic is a huge problem worldwide,” says Lei. “This is a very good, and relatively simple, way to recycle these plastics.”
The process is highly efficient. “We can recover almost 100 percent of the energy from the plastic we tested,” Lei says. “The fuel is very good quality and the byproduct gasses produced are high quality and useful as well.” The process is easily scalable, making it suitable for use in factories or on farms, where farmers could turn plastic waste into diesel. “You have to separate the resulting product to get jet fuel,” Lei said. “If you don’t separate it, then it’s all diesel fuel.”
While the research is encouraging — there are billions of tons of waste plastic in the world and finding a commercially viable use for it could reinvigorate the recycled plastic industry — wouldn’t it be better to stop making millions of tons of new plastics every year?
The conundrum is similar to the carbon emissions problem. While some researchers are busy finding ways to recapture CO2 in the atmosphere and turn it into fuel, or rocks, or (yikes!) more plastics, wouldn’t it make more sense to stop burning fossil fuels in the first place? Lei’s work may be an important part of solving the plastic waste problem, but it should also shine a light on the ignorance of people who would gladly trade the future of the Earth for the convenience of throw away water bottles.