Science

Researchers convert plastic bags into a variety of petroleum products

Researchers convert plastic ba...
Brajendra Kumar Sharma, center, with research chemist Dheeptha Murali, left, and process chemist Jennifer Deluhery, converted plastic shopping bags into diesel fuel (Photo by L. Brian Stauffer)
Brajendra Kumar Sharma, center, with research chemist Dheeptha Murali, left, and process chemist Jennifer Deluhery, converted plastic shopping bags into diesel fuel (Photo by L. Brian Stauffer)
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Used plastic shopping bags can be converted into petroleum products that serve a multitude of purposes (Image: Julie McMahon)
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Used plastic shopping bags can be converted into petroleum products that serve a multitude of purposes (Image: Julie McMahon)
From plastic bags, the team produced equivalents of (from left to right, in vials) gasoline, diesel #1, diesel #2 and vacuum gas oil (Photo: L. Brian Stauffer)
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From plastic bags, the team produced equivalents of (from left to right, in vials) gasoline, diesel #1, diesel #2 and vacuum gas oil (Photo: L. Brian Stauffer)
Brajendra Kumar Sharma, center, with research chemist Dheeptha Murali, left, and process chemist Jennifer Deluhery, converted plastic shopping bags into diesel fuel (Photo by L. Brian Stauffer)
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Brajendra Kumar Sharma, center, with research chemist Dheeptha Murali, left, and process chemist Jennifer Deluhery, converted plastic shopping bags into diesel fuel (Photo by L. Brian Stauffer)
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Despite efforts to limit their use through implementation of charges or bans, billions of plastic bags continue to clog landfills, waterways and the world's oceans every year. Already a potential source for carbon fiber and carbon nanotubes, researchers have provided another reason not to throw the ubiquitous bags away by converting them into a range of petroleum products.

The researchers from the Illinois Sustainable Technology Center (ISTC) at the University of Illinois used a process known as pyrolysis, which involves heating the plastic bags in an oxygen-free chamber. Although this technique has been used by other research teams to convert plastic bags back into crude oil (which they are originally produced from) the U of I team went the next step and fractionated the crude oil into different petroleum products.

From plastic bags, the team produced equivalents of (from left to right, in vials) gasoline, diesel #1, diesel #2 and vacuum gas oil (Photo: L. Brian Stauffer)
From plastic bags, the team produced equivalents of (from left to right, in vials) gasoline, diesel #1, diesel #2 and vacuum gas oil (Photo: L. Brian Stauffer)

In this way, the researchers were able to produce natural gas, naphtha, gasoline, waxes, and lubricating oils, such as engine oil and hydraulic oil. They also produced diesel that can be blended with existing ultra-low-sulfur diesels and biodiesels, which the team tested for compliance with US standards.

"A mixture of two distillate fractions, providing an equivalent of U.S. diesel #2, met all of the specifications required of other diesel fuels in use today – after addition of an antioxidant," said Brajendra Kumar Sharma, a senior research scientist at the ISTC. "This diesel mixture had an equivalent energy content, a higher cetane number (a measure of the combustion quality of diesel requiring compression ignition) and better lubricity than ultra-low-sulfur diesel."

The team blended up to 30 percent of the plastic bag-derived diesel into regular diesel with no problems and found no compatibility issues with biodiesel.

"It’s perfect," said Sharma. "We can just use it as a drop-in fuel in the ultra-low-sulfur diesel without the need for any changes."

Sharma says the conversion process also produces significantly more energy than it uses. "You can get only 50 to 55 percent fuel from the distillation of petroleum crude oil," he said. "But since this plastic is made from petroleum in the first place, we can recover almost 80 percent fuel from it through distillation."

The team's study appears in the journal Fuel Processing Technology.

Source: University of Illinois

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12 comments
Carol Zedeck
I'm finding it hard to understand the notion that this produces "more" ENERGY than it requires. My guess is that this notion comes about from not factoring in all the energy inputs required to run the process and to produce the additives......Can someone respond to this??? Most processes I am familiar with, if not all, seem to balance out along the way, as much as we would love to have a better energy deal.....
BeWalt
Cool. Like having an undo button on a thing made from crude oil.
Which gets me to the stupid side of our usage of crude oil: Burning it for one-time purposes such as transportation. Once done, it's gone. No undo button.
What a difference.
CaptD
I predict soon there will be a "Gold Rush" of harvesting vessels that will compete with each other to turn the huge "Vortex of Waste" now floating in the Northern Pacific Ocean into much needed raw materials in the most efficient way.
Good news for the Planets ecology!
Jack Rock
In response to Carol Zedeck:
I do not know for certain, but here are my assumptions. They are calculated "energy used" as the input energy required to put the bag through pyrolysis, and the "energy output" as the usable energy derived through combustion of the resultant fuel.
In this way, it is not violating the 2nd law of thermodynamics, because there is significant chemical energy stored in the bag which is converted into a more useful form through the research team's process.
This is not dissimilar to the act of extracting and refining oil; if it took us more energy to extract and refine the oil than we actually got out of using the oil, it would be pointless to even go through the process :)
Hope that cleared it up a bit?
Ron Evans
I am excited at all the calories that will be burned by people climbing trees to get the bags. O also walking waterways collecting all the bags caught there. As the Beatles sang, "Let It Be"
Stephen N Russell
More reason & save & now reuse for Fuel vs waste, awesome theres our fuel America, no more from OPEC, all from plastic bags, & in CA we ban plastic bags, maybe reuse for Fuel then OK Governor Brown.
BMFan
Shopping bags made from LDPE & HDPE are 100% recyclable so why not just turn them back into bags which is less effort and energy than turning them into petroleum products
Martin Winlow
@CaptD
I predict (and have done for ages) that, one day, we will start mining landfill sites for all those precious things that were once just rubbish.
Slowburn
@ BMFan
This process won't be ruined by a bit of the wrong plastic being put in the mix thereby saving huge amounts of energy from not having to sort the mix.
u-day
This was done before
A japanese scientist did Blest Machine
https://www.youtube.com/watch?v=KBUGAUGqaY4
A man from ethiopia made it
https://www.youtube.com/watch?v=1Qi54pTAXZ4