Each year, Americans discard about 100 million plastic bags, while only 13% are recycled. The rest of the bags end up in the trash or as free-floating litter. Due to environmental concerns, the plastic bag is being slowly phased out, with some cities restricting or even banning their use in retail and grocery stores; at the same time, we are finding new ways to recycle plastic bags already in circulation.
Researchers at the University of Illinois at Urbana-Champaign’s (UIUC)Sustainable Technology Center (ISTC) recently reported that through pyrolysis, a process which breaks down material in the absence of oxygen, they were able to covert 80% of a petroleum-based plastic bag into fuel meeting national U.S. standards for diesel. The researchers, led by scientist Brajendra Kumar Sharma, published their 2014 findings in Fuel Processing Technology.
The ISTC team have built on previous research into extracting crude oil from plastic bags, by refining the oil, adding an antioxidant, and producing a diesel product comparable to U.S. Diesel No. 2. They then blended 30% of their product into diesel, with “no compatibility problems,” according to Sharma. “We can just use it as a drop-in fuel in the ultra-low-sulfur diesel without the need for any changes,” he told the UIUC’s News Bureau.
Currently this technology may only be available on a household scale to experienced DIY chemists, and to those who can afford to purchase pre-built fuel conversion devices such as those made by the Japan-based Blest Corporation. Most of us will have to wait until the technology expands into the commercial arena.
A team of Indian researchers compiled a 2014 report for the International Journal of Environment and Waste Management detailing their development of a method, also through pyrolysis, of converting the low-density polyethylene (LDPE) in plastic bags to fuel using the clay mineral kaolin as a catalyst. Their aim was to use the kaolin to increase the yield at lower temperatures, as well as to reduce the amount of reaction time. The researchers, chemist Achyut Kumar Panda and chemical engineer Raghubansh Kumar Singh, intend the method as a way to efficiently convert plastics to fuel on a commercial scale. With a 1:2 ratio of kaolin to plastic, Panda and Singh were able to produce up to about 8% more fuel than without the catalyst. Like ISTC, they reported that the properties of the oil were similar to that of diesel fuel.
Panda and Singh, as well as Sharma’s team at ISTC, hope that the use of plastic bags for diesel fuel could reduce their presence as a major pollutant; plastic bags contribute to the clots of discarded plastic and other garbage that make their way into oceans and disrupt both coastline and marine wildlife.