Researchers at the University of Illinois, or more precisely the Illinois Sustainable Technology Center, have discovered a process that can turn used plastic shopping bags into a compatible drop-in diesel fuel and a number of petroleum products. The recycling process also works to recover most of the initial manufacturing inputs that go into producing plastic shopping bags. Given that each year an estimated 100 billion shopping bags are thrown away in the US alone, this is great news indeed.
According to the researchers, the recycling process actually produces a lot more energy than it requires, along with resulting in the creation of transportation fuels such as diesel. The latter can then be blended with existing ultra-low-sulfur diesels and biodiesels. The other products that can be obtained by this shopping bag recycling process include natural gas, naphtha, gasoline, waxes and lubricating oils, namely engine oil and hydraulic oil. As the lead researcher, Brajendra Kumar Sharma, put it: “You can get only 50 to 55 percent fuel from the distillation of petroleum crude oil. But since this plastic is made from petroleum in the first place, we can recover almost 80 percent fuel from it through distillation.”
To recycle the shopping bags, the researchers used a process called pyrolysis, which has been used previously to transform plastic bags into crude oil products. The process works by heating the plastic bags in an oxygen-free chamber to obtain the oil. However, the University of Illinois research team has managed to refine the material created through pyrolysis into different petroleum products, and have achieved their goal of producing a fuel that meets the standards for ultra-low-sulfur diesel and biodiesel fuels.
The results of their study revealed that the fuels which result from their process can be blended into regular diesel at rates of up to 30%, without any compatibility issues or any necessary changes. In fact, nearly all properties of the produced fuel were within ASTM D975 and EN 590 diesel specifications, while the derived cetane number (the measure of the combustion quality of diesel requiring compression ignition), and lubricity were superior to conventional diesel fuel.
These findings are very promising, since they could prove to be the answer of how to successfully and effectively recycle plastic bags. However, before the process can be used to recover the initial inputs from manufacturing plastic bags and reduce the amount of petroleum required for diesel and other fuels, it must first be successfully scaled up to help in dealing with the massive amounts of discarded shopping bags. The challenge of getting people to recycle their shopping bags, however, still remains.