Turning Plastic Waste Into Energy

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Plastic waste is choking our oceans, killing wildlife, and its nanoparticles are finding their way into almost every living being. Last year, in a study reported by the Guardian, microscopic plastic particles were found in the blood of 80% of the human subjects tested.

Team 24011 is building an apparatus that would turn waste plastic into energy via pyrolysis, an intense heating process. The idea is that it could be used in natural disaster recovery efforts or in very remote locales, to convert available waste to provide emergency power.

Burning plastics, at first blush, does not seem to be a net positive environmentally, but there are some critical caveats here. First, pyrolysis is a controlled heating process, explained Raphael Lepercq,  who is an adviser to the team and completed his UA master’s degree in electrical and computer engineering in December 2023.

“It burns the material to break it down, but not to the point of conflagration,” said Lepercq, who is now a junior software engineer at PeakView Solutions, which is sponsoring the project.

In addition, the process restricts harmful byproducts. “It's thermal decomposition in the absence of oxygen. So it's basically burning it, but without the air,” said Daniel John Hutton, the student project leader. “When you do that, instead of combustion products like carbon dioxide, carbon monoxide, and other greenhouse gases and toxic chemicals, you actually get just the decomposed polymer.”

The energy product from the pyrolysis is a light hydrocarbon, which is a hydrocarbon with a low molecular weight, like butane or propane. “We’re essentially taking the plastics, which have been created from crude oil, and turning them back into a something like gasoline or diesel that can power a generator,” said Hutton, a chemical engineering major. “The main environmental benefit is removing plastics from the environment in a virtually emission-free way, and you have a negative net carbon effect as you’ve removed it from sources that were already contaminating the environment.”

Lepercq said the team is working hard to have a prototype ready for Craig M. Berge Design Day on April 29. “That’s the plan. Hopefully we can even have visitors bring their own plastic waste to toss into the machine,” he said. “It might take a few hours, but they could come back and see the fuel that was produced from that trash.”

For Hutton, the pyrolysis project could have been specifically designed for his career ambitions. When he saw the description last summer, he applied to join the team right away.

“I am really interested in using chemical catalysis to convert waste feed stocks like plastics, biomass and other materials that we normally have to throw away into usable, sustainable chemicals,” Hutton said.

According to Manny Miera, founder and CEO of PeakView Solutions, the team has gelled and is hitting top gear at just the right time.

 “It has been an amazing experience working with the students. At the beginning of the project, most of them didn't know each other,” said Miera, a 1992 computer engineering graduate. “I’ve seen them transform from a disparate group with different engineering backgrounds to a unified team.”

“For PeakView, this is an opportunity to give back to the University of Arizona and the community of Tucson where I grew up,” he said. “There’s no doubt that my experiences at the university, including my own capstone project, contributed to the success of founding PeakView Solutions 17 years ago.”