Posted on 04/23/2021 12:20:00 PM PDT by Red Badger
If you didn't know already, we have bad news - the plastic recycling industry is severely under-performing. Only 9 percent of plastic waste ever produced has been recycled. Around 12 percent has been burnt, leaving 79 percent of all plastic ever produced still out there in the world.
While we work out how to be less reliant on these materials, researchers have also been investigating how to reuse one of the most common types of plastic – polyolefin – by turning it into fuel.
"Single-use plastics impose an enormous environmental threat, but their recycling, especially of polyolefins, has been proven challenging," researchers from the University of Delaware (UD) write in a new paper.
"We report a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons."
This is definitely not the first time scientists have turned plastic into fuel (in fact, we've been reporting on these methods for years), but like most material sciences, the goal is to get the most plastic converted into the most fuel, at the cheapest cost and using the least amount of resources to do so.
The new technique ticks plenty of those boxes: it uses 50 percent less energy than similar technologies, can be done at temperatures of a normal kitchen oven, and doesn't involve adding carbon dioxide into the atmosphere. All exciting steps in the right direction.
"Plastic waste is a serious environmental issue. I believe that this research can help lead to better methods of plastic repurposing," said Andrew Danielson, a UD chemical engineer.
The team uses a chemical process called hydrocracking to break down the carbon bonds in the plastic, using a catalyst made up of minerals called zeolites and mixed metal oxides.
plastic fuel (Liu et al., Science Advances, 2021)
Mixed metal oxides are used to break down large molecules, while zeolites foster the formation of branched molecules – a technique which makes the plastic goop more easily translated into an end product.
"Alone these two catalysts do poorly. Together, the combination does magic, melting the plastics down and leaving no plastic behind," UD biomolecular engineer Dion Vlachos said.
"These are not exotic materials, so we can quickly start thinking about how to use the technology."
As an added bonus, the team's process doesn't need to separate different types of plastics, which is helpful when many of the plastic products now sold are multicomponent - either as composites, blends, or having multiple layers of different types.
This is far from the end of plastic waste, of course, and only deal with one symptom of the larger issue. To create a circular economy, we have to eventually stop pulling oil from the ground to make plastic, which is something that the researchers are well aware of.
"As this circular economy gets going, the world will need to make fewer original plastics because we will be reusing materials made today into the future," Vlachos said.
"We want to use green electricity to drive the chemical processing involved in making new things … that's where we are headed over the next 10 to 20 years."
Sounds like itis time to get started.
The research has been published in Science Advances.
My kitchen oven is warming up as I type this.
You tie them to a 2X6 and cook them over an open flame for 6-8 hours. Then eat the 2X6.
He is definitely a consummate actor.
I think he’s retired? No?................
Take the challenge!
I do like him though.
Wheelabrator Technologies burns our trash here in NH, boils water, turns a turbine with the steam and produces electricity.
Trex, Azek/Timbertech and several other composite decking manufactures are turning plastic back into a product that is replacing wood decking.
I have always thought one of Hoffman’s best movies was “Marathon Man”.
Although, Lawrence Olivier’s character was more memorable.
“Is it safe?”
He was good in Papillon, one of my all-time favorite movies.
But what about tires? Steel belted radials?
We already recycle those................
No, the picture at the site is not one of the fungus mentioned.
Doesn’t it take more energy to convert?
I’m waiting for the day they can convert discarded rubber tires into metallurgical coal. (not just any old coal, met coal is specific to blast furnaces = steelmaking)
It’s a fairly low temp, 200°C - 250°C reaction..................
Plastic wastes provide asphalt with an average compressive strength of 23.8 MPa. Another commonly used material in pavements is used rubber tires. These tires can come from cars, trucks, trailers, and many other venues as well.
We have nuclear technology that can be put to use RIGHT NOW to take care of the needs of “green” electric power generation.
Uranium-fueled Light-Water reactors are coming to the end of their useful lifetimes, and there is great resistance to beginning construction. But while they were running, they emitted NO carbon dioxide, and they could run flat-out full output 24/7/365 for years at a time until needing refueling. Of course, one of the great disadvantages is that when they WERE refueled, the “spent” uranium fuel rods were still highly radioactive, and would remain so for perhaps centuries. So there was the problem of storage of this radioactive “waste”, and who were going to be the custodians at it “cooled out”.
Enter Thorium-fueled Molten Salt reactors. For one thing, the element needed for fuel is some four times as abundant in the earth’s crust as uranium, but its radioactivity could only be activated in the presence of a small amount of the vast quantity of “spent” uranium fuel rods. More than 90% of its potential energy still remains in the “waste” fuel, which is used for “kindling” to get the thorium reaction going. So over time, the “spent” uranium fuel rods get used up, and the amount of radioactivity in the spent thorium reactor fuel is very small in comparison, and compromised of relatively short half-life isotopes.
But like the Light Water reactors, the Molten Salt reactors can be run 24/7/365 for years, and have the advantage of being able to be incrementally refueled “on the go”, so to speak. The real problem comes with the breakdown of the container and the components of the reactor, which tend to become brittle. But even if the mechanism should burst, the reaction stops almost immediately, as the molten salt cools, and there is no radioactivity release. Inherently much safer than Light Water reactors.
The reason that the decision was made to go with uranium as fuel, and not thorium, was that the uranium fuel broke down into bomb-grade plutonium, and thorium does not.
I know, but at quite a cost, as opposed to just “dropping them off.” And the steel adds complications in grinding. A vast number are just sitting around, discarded, in various sized piles.
More power to them if they have improved the economics of recycling.
You want to recycle EVERYTHING in a landfill? The technology for that already exists, as well.
Plasma gasification is an extreme thermal process using plasma which converts organic matter into synthesis gas called Plasma Converted Gas (PCG), syngas or Hydrogen and Carbon Monoxide, both combustible fuels, which can then be burned to generate electricity at the site, through a steam driven turbine that uses superheated steam, or directly as a ground-based gas turbine.
Our heating fuel is 20% this stuff.
When I pulled the rear of my System 2000 boiler to clean it last d=fall, it was the cleanest it has ever been.
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