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New Chemical Process Can Convert Nearly a Quarter of All Plastic Waste Into Fuel (vice.com)
"Researchers at Purdue University have developed a new chemical process that they say can convert approximately one-quarter of the world's plastic waste into gasoline and diesel-like fuels," writes Slashdot reader dmoberhaus. Motherboard explains how it works: As detailed in a paper published this week in Sustainable Chemistry and Engineering, the chemists discovered a way to convert polypropylene -- a type of plastic commonly used in toys, medical devices, and product packaging like potato chip bags -- into gasoline and diesel-like fuel. The researchers said that this fuel is pure enough to be used as blendstock, a main component of fuel used in motorized vehicles. Polypropylene waste accounts for just under a quarter of the estimated 5 billion tons of plastic that have amassed in the world's landfills in the last 50 years.
To turn polypropylene into fuel, the researchers used supercritical water, a phase of water that demonstrates characteristics of both a liquid and a gas depending on the pressure and temperature conditions. Purdue chemist Linda Wang and her colleagues heated water to between 716 and 932 degrees Fahrenheit at pressures approximately 2300 times greater than the atmospheric pressure at sea level. When purified polypropylene waste was added to the supercritical water, it was converted into oil within in a few hours, depending on the temperature. At around 850 degrees Fahrenheit, the conversion time was lowered to under an hour. The byproducts of this process include gasoline and diesel-like oils. According to the researchers, their conversion process could be used to convert roughly 90 percent of the world's polypropylene waste each year into fuel.
To turn polypropylene into fuel, the researchers used supercritical water, a phase of water that demonstrates characteristics of both a liquid and a gas depending on the pressure and temperature conditions. Purdue chemist Linda Wang and her colleagues heated water to between 716 and 932 degrees Fahrenheit at pressures approximately 2300 times greater than the atmospheric pressure at sea level. When purified polypropylene waste was added to the supercritical water, it was converted into oil within in a few hours, depending on the temperature. At around 850 degrees Fahrenheit, the conversion time was lowered to under an hour. The byproducts of this process include gasoline and diesel-like oils. According to the researchers, their conversion process could be used to convert roughly 90 percent of the world's polypropylene waste each year into fuel.
less than 100% efficiency is still less than 100%
The image of water that is both liquid and gas is amusing
Plastic is literally fuel for the burner as it's almost always made out of petrochemicals. Why would you lose a massive amount of energy to make it a liquid fuel instead of a solid one?
So, they have discovered a method to convert millions of tons of plastic into fossil fuels that can be burned to release yet more sequestered carbon into the atmosphere. That's sure to solve our ongoing problem with carbon emissions causing climate change.
Their conversion process could be used to convert roughly 90 percent of the world's polypropylene waste each year into fuel.
Then we can put this fuel into our cars and burn, dumping all that carbon into the atmosphere, where it can no longer be any harm to our planet.
Oh wait...
My grandma's stove converts 100% of plastic waste into heat fuel.
At high enough pressures and temperatures, anything with carbon will turn into light hydrocarbons.
But if it turns out that the math means this is practical, then this would be very cool.
Put it in the wood-burning stove and enjoy free fuel for life.
So whatever plastic is currently capturing carbon, can return it right back into the atmosphere.
Plastics containing just H and C can probably be burned without much processing. The problem is that most recycled plastic is a mix of all sorts, including a lot of popular Cl containing plastics that are really nasty to burn.
If there are sources of sufficiently pure hydrocarbon plastics (polyethylene, polypropylene and the like) and if this is more cost effective and energy effective than other methods, its fine. I expect the bigger problem is the initial purification. Maybe there is a solution to separating out the other plastics?
But let's talk about how energy intensive it is to get water into that supercritical state.
Probably so expensive with current "green" technology that it would make more sense to just work on optimizing fossil fuel usage.
Sure we could achieve this easily with nuclear power, but with dolts like Ocasia-Cortez running around trying to gut our nuclear industry it just ain't going to happen.
Cool science, but not readily useful.
So with huge amounts of energy, they can covert low-cost waste into fuel that can release small amounts of energy. Kind of like how you can fuel your car with corn, if you spend more hydrocarbons growing and processing it that you get as energy in the ethanol.
And advocates that as completely without health risk.
Is the chemical process called fire? cause plastic already burns and powers many cities trash to power conversation centers.
Scientific writing should always be in celsius, with farenheit in parentheses.
between 716 and 932 degrees Fahrenheit = 380C to 500C. Looks like the author already took the perfectly workable celsius and obfuscated it by turning it into farenheit, which is stupid since no human would have an appreciation of what 716 farenheit is like compared to the normal temperature ranges they're familiar with anyway.
around 850 farenheit = around 450C.
As they are just taking resources and providing nothing for society
Critically absent from this article is the amount of engergy required for the process, and what the net gain or loss is. Need to read the paper.
OLD NEWS!
I remeber, around 2010, this crazy old japanese dude claimed he invented the process using a modified electric rice cooker.
Sauce: http://www.blest.co.jp/eng/envronmental/
isoenergetic conversion has to be better.
Some drink at the fountain of knowledge. Others just gargle.
Yeah!
Whatever you are talking about.
Anyway, I hope all those countries dumping plastic in their rivers take note of this.
At least until they smarten up like the old USA!
Now, if they're going to convert plastic into fuel, which plastic do you think they're going to use? Obviously the former. Meaning (1) it will have zero effect on plastic pollution in the environment, and (2) you're just spending extra energy and money to convert petroleum byproducts into fuel, instead of just using new petroleum as fuel. You're just paying extra to swap carbon sequestered underground as plastics, for carbon sequestered underground as natural petroleum.
Any solution to address environmental plastic pollution must address the non-collection problem. That means either enforcing proper disposal of plastic waste, designing plastic waste to degrade more quickly in the environment, or reducing the use of plastics entirely. This plastic to fuel idea does none of these things. The only thing it does is reduce the space taken up in landfills.
I remember my chemistry professor talking about how stupid it was to recycle plastics. He said we should just burn them for electricity instead of sorting, transporting, and otherwise expending all kinds of energy and effort in recycling. I'm guessing he brought this up in class because the city was debating a waste to energy plant and that burning plastics was part of that debate.
What I'm wondering is where the energy would come from to reach these intense temperatures and pressures for this process. Not many things burn this hot. Would this be a kind of coal blast furnace like that used to make steel? That seems like a rather silly idea if the goal is to reduce the production of waste and CO2.
There is a technology that can reach these temperatures. This technology also produces very little carbon, and theoretically none. That is the molten salt reactor, nuclear power. The US Navy is developing a technology much like this, only they use carbon sourced from CO2 dissolved in seawater. They want high temperature reactors too. Although the high pressures like this process uses might turn them off. They want to get away from the use of high pressure steam as that created inherent hazards to the crew on a ship. High temperatures are also a hazard but a ship at sea is surrounded by a huge heat sink, and any steam from that hot stuff meeting the water would be at atmospheric pressures.
This plastic to fuel process is a nice idea but hardly new. I believe that gentlemen named Fischer and Tropsch developed this same process nearly a century ago in Germany. All they are doing is limiting the feedstock for the process to plastics, but the process would work on most any carbon based material.
I am armed because I am free. I am free because I am armed.
That would be interesting.
The abstract, though, says: "supercritical water at 380–500 C and 23 MPa" which is 230 bar, which is still a respectable pressure (3300 psi) but the sort of "reasonable" pressure encountered in modern steam turbine power generation, etc.
less than 100% efficiency is still less than 100%
“The best is the enemy of the good.” - Voltaire
"Better a diamond with a flaw than a pebble without." - Confucius
If you think you're so damn smart, invent a better method. Or kindly STFU.
It is not a solution to carbon emission. However it will not "Increase" fuel consumption (Thus CO2 emission) by itself, merely replace some of it. If the claim is true then it will reduce the extra plastic problem that polluting every corners of the Earth.
> estimated 5 billion tons of plastic that have amassed in the world's landfills
Plastic is lighter than water and water weights 1 ton per 1 cubic meter. So, ideally packed 5,000,000,000 tons of plastic would fit into 5 cubic kilometers, e.g. 5 km x 10 km x 100 m landfill. I don't see a problem. It looks like a very good way to keep carbon from atmosphere.
Nature has been creating oil by this process for millions of years.
Where does the energy come from to heat water tp 900F and compress it to 2300 BAR? That is an IMMENSE amount of energy.
Why not just use the waste to create a durable good like deck material, park benches, and so on?
Did I say that? I said you're a moron who advocates microplastic in food because you assert it has no health effects. Who's stalking? Your faggot ass blurted that out and then came back to blurt this dumbass shit.
Get laid professor. You know nothing about this.
What I'm wondering is where the energy would come from to reach these intense temperatures and pressures for this process. Not many things burn this hot. Would this be a kind of coal blast furnace like that used to make steel? That seems like a rather silly idea if the goal is to reduce the production of waste and CO2.
The pressures are hard, yes. But the temperature is easy. Every flame I've heard of will reach that temperature (500C). Even a candle flame reaches 1000C.
A cat can't teach a dog to bark.
less than 100% efficiency is still less than 100%
But the energy could come from solar, wind... nighttime use of those nuclear reactors we ought to be building.
(given that electricity storage is difficult, could this process make nuclear reactors more profitable?)
No sig today...
"At least until they smarten up like the old USA!" Didn't you miss your [sarcasm] tags
You shouldn't need high temperature or pressure to burn these in a trash-to-smoke power plant. (I think the fancy term now is "co-generation" but I'm a bit behind on the latest buzz words). If you burn *just* plastic, you may need to be creative but if you mix it with other things that burn easily (such as paperboard), it should all just burn and generate heat. If not just add something that burns hotter to the mix. If you can *separate* the plastic, I suggested in a previous post just to mix it with your coal stream at existing coal-fired plants. They do this with wood pellets already.
Holy fuck people...
From the linked journal:
temperature: 450 C
pressure: 23 Mpa
It is not 2300 bar, it's 230 bar.
Standard propane burns at 1980 C in air and thats the same pressure as a scuba tank. So temperature and pressure are easy to achieve. This can reduce solid plastics waste and potentially reduce the consuption of crude oil.
And maybe we can stop dumping plastics in the ocean and killing all the damned sea life.
Oh yeah, stop burning plastics. The extraneous chemicals in there are going to kill you and the surrounding environment.
To expand on this, it's ridiculously cheap and easy to build a propane or charcoal-fired crucible that will readily melt aluminum at temperatures substantially higher than what's needed here. As you point out, the difficulty is not the temperature, but in handling the required pressures.
Please stand clear of the doors, por favor mantenganse alejado de las puertas
Wonder want happens to non-PP plastics that are in the mix? It's the waste sorting that costs.
There are plenty of locations with waste heat that could co-power a process like this for low incremental cost. So those bleating about 100% efficiency are walking the wrong road.
Turning what is otherwise waste into something *useful* is definitely a plus.
Ferret
Sic gorgiamus allos subjectatos nunc
And the energy cost to raise the temperature to 450C? And to pressurize at 2300 atms? For hours?
I have a feeling this would cost far, far more, than the energy in the fuels obtained...hmmmm....
...is sorting plastic waste. How are they going to separate polypropylene from the other plastics? Has anyone come up with a cost effective way to do it that doesn't involve child labour in developing countries?
How many more will there be? Turning CORN into fuel was a wasteful enterprise, that benefits only the "farm industry". Many other things can be turned into fuel.
The pressures are hard, yes. But the temperature is easy. Every flame I've heard of will reach that temperature (500C). Even a candle flame reaches 1000C.
But how can they get to these temperatures without burning anything? The goal, so it seems, is to avoid carbon going into the atmosphere.
I assume electric heat can get hot enough but then there is still the question on where to get the energy. Any heat engine that converts boiling water to steam for turning a turbine would be quite wasteful use of that heat if the electricity is then just run to an electric heater. If there is something that is hot enough to begin with then the inefficient process of converting the heat to electricity and back again can be avoided.
Solar thermal might get hot enough but only for a few hours per day. There's no wind or hydro process that gets this hot. Burning bio-mass might be carbon neutral but that's burning a lot of stuff that could be better used for food, clothing, fertilizer, or erosion control.
I say we just burn the plastic. I'm guessing my chemistry professor would still agree.
In the end the carbon in the plastic is still burned, only as a higher grade fuel by "upgrading" into something more convenient and having a higher market value. I'm constantly "reminded" that the future is electric cars anyway (which I do not believe but whatever). If true then this process will become worthless before it ever gets started.
I say don't bother, just burn the plastic to make electricity. I'm convincing myself of the futility of this process as I type this. Interesting chemistry, that's certain, just unlikely to be economically or environmentally viable.
I am armed because I am free. I am free because I am armed.
What throughput in this process ?
How many energy do they consume to transform back these plastics ?
Woudn't be better to directly use this energy for the final usage ?
-- Laurent Pointal
One way or another, the solution to all plastic waste is to blow it out of tail pipes hither and yon.
No U. Not my problem.
Just shut up already. You disqualify yourself with the ridiculous statement about the difficulty of achieving those high temps. A common cigarette lighter burns hotter. So I guess we are supposed to consider nuclear power advice from you? Yeesh.
Produces energy and gets rid of nasty byproducts.
Yep, my mistake for confusing Fahrenheit for Celsius. There's still the issue of where this energy comes from. Nuclear power is still the lowest carbon energy source we know of. Anything other than nuclear power is not nearly as good of a solution for the reduction of global warming. Best part is it produces the heat needed without the inefficiency of converting the energy collected into electricity and then converting that into heat.
Is global warming a problem? Then let's use the best tools for the job to fix it.
I am armed because I am free. I am free because I am armed.
All the electricity they put in to convert the plastic in a fuel, probably doesn't return 10% from the fuel so created. It would be more efficient to use the electricity directly to do the things we normally would do, such as charge the battery in an electric vehicle. Also, you can use plastic directly as plastic to do plastic things -- like making reusable shopping bags -- at probably 1/1000 the energy requirement of making fuel from the same material.
No. This has nothing to do with finding a use for plastic. It has everything to do with making a story about how we're going to keep current-technology ICE automobiles and trucks on the road for longer. In 5 years when people are losing their minds over how we use fossil fuels, the transportation sector and trot out their "oh but we run on plastic now" pony. It doesn't even need to be technically true, they can make the claim and most people would just shrug and go back to watching the Kardashians.
=^..^= all your rodent are belong to us
I was going to post s.t. like this, but you beat me to it.
Decades ago, I was Main Propulsion Assistant on a Guided Missile Destroyer. It was propelled by steam turbines, with steam at 1200 psi and 975 degrees (superheated). That's ~80 bar, and the steam was truly dangerous. A leak wouldn't scald you, it'd cut you in half. (I avoided that, as you may have surmised.) Some land-based boilers go higher than that, perhaps 3500 psi, or ~240 bar. For this plastic operation, they're talking nearly an order of magnitude higher than that. I can't imagine what kind of apparatus that would take (not just the pressure vessel), how much fuel (presumably plastic, but still) it would have to burn, and how long the cool-down would be to get the oil back out and put more plastic in. Unless you could somehow shred the plastic, add water, and pump that into the pressure vessel. But that would be one heck of a feed pump to pressurize to 2300 bar.
I think a better idea would be to let nature do the work: drop the plastic into a subduction zone, and wait for the oil to come back up.
Might oughta stand clear of the 2300 bar pressure vessel, too...
Oops, there was a mistake in the synopsis of the article here at /. The pressure the experiment used was 23 MPa =~ 3300 psi--NOT 2300 bar. Off by an order of magnitude. This is still a very high (and dangerous) pressure, but not as outlandish as it seemed.
BTW, there are two links in the /. article. The first is too motherboard.vice.com, and that contains the incorrect figure of 2300 * atmospheric pressure. That's apparently where the 2300 bar figure in /. comes from. The other link is to an abstract written by the scientists, and it uses the figure of 23 MPa. The abstract (and presumably the full article) also addresses another issue brought up by commenters here: "Preliminary analyses indicate that this conversion process is net-energy positive and potentially has a higher energy efficiency and lower greenhouse gas emissions than incineration and mechanical recycling."
https://slashdot.org/comments.pl?sid=12642660&cid=57354060
Because we couldn't use clean energy like solar or wind (that is battery backed if you want more reliability) that uses a resistive heating wire (like an electric stove top element)?
Burning plastic releases highly toxic gasses and unless you have extremely hot incinerators with scrubbers to remove all the toxins then you're going to make people sick. Also the ash & sludge from the incinerator is highly toxic too.
The conversion process sounds expencheap, I wonder how practical this conversion is in a real world scenario.
Because we couldn't use clean energy like solar or wind (that is battery backed if you want more reliability) that uses a resistive heating wire (like an electric stove top element)?
Right, you can't. Solar and wind power cost too much, is horribly unreliable, takes an incredible amount of land and other resources, and any claims that batteries will solve these problems only adds to the cost and resources consumed.
Burning plastic releases highly toxic gasses and unless you have extremely hot incinerators with scrubbers to remove all the toxins then you're going to make people sick. Also the ash & sludge from the incinerator is highly toxic too.
Assuming that's true, that we can't burn it safely and/or economically, then bury it. We aren't going to run out of holes to dump things into any time soon.
I am armed because I am free. I am free because I am armed.
The rule of thumb is that hydrocarbons contain around 9 kcal of energy per gram. One kcal is enough to raise a gram of water by a thousand degrees, and almost every other substance is heated more easily than water (specific heat being around 1/4 to 1/2 that of water). PP has a specific heat of 0.46 calorie per gram degree. If my math is correct, burning one gram of plastic (not necessarily PP) could heat a little over 5 grams of PP to the needed temperatures.
A cat can't teach a dog to bark.
"When purified polypropylene waste is added..."
Which of those streams contains PURIFIED waste ?!?!?
I am sure someone can come up with a plan to turn anything into something. The problem is that pile of plastic contains a dozen anythings in unknown ratio at the same time.....none of which will be 'purified'
PURIFIED waste stream should hold me throughout the day tho :O Theory Reality