While fuel shortages due to the Iran war made some countries double down on electrification, they also highlighted one industry that could be quite literally grounded without fossil fuels: aviation. Flying relies on fossil-based jet fuels and is extremely hard to decarbonize.
Researchers in China now report a process that could help bring down flying’s carbon emissions while also tackling the plastic waste crisis. The two-step process converts plastic waste into high-quality jet fuel more efficiently and at much less cost than other methods researchers have reported in the past to convert plastic waste to fuels.
The team’s preliminary analysis, reported in published in Nature Energy, shows that the plastic-based fuel would cut carbon dioxide emissions by 73% compared with petroleum-based jet fuel.
The plastic that the researchers break down is polystyrene. This lightweight polymer, often commonly called Styrofoam, is used to make packaging and insulation. It is notoriously expensive and challenging to recycle. Besides usually being contaminated, it is composed mostly of air, which makes sorting and transportation difficult. Nearly all waste polystyrene goes to landfill today.
The team from Nanjing Forestry University and Tsinghua University designed a new catalyst that breaks down polystyrene at high temperatures in the presence of hydrogen. Their process runs continuously in a tandem reactor.
Both are hydrocarbons, right? I expected the petroleum-to-plastic synthesis to be one-way though
Not really, there are also polyesters and polyamides. These used here are hydrocarbons, and turns out there's a tool for that. You see, in oil refining there's a lot of stuff manufactured that it's useless without further processing, as in, after distillation and vacuum distillation you might end up with half of weight of oil or more as asphalt or heavy oils that barely can be sold. So in order to make them useful, these products are broken down into smaller molecules, and then are separated again. What they're doing is similar to process called hydrocracking that is commonly used to turn heavy vacuum distillates, think something like motor oil or other greases, to diesel