Continuous System For Converting Waste Plastics Into Crude Oil

rtoz writes: A MIT spinout company aims to end the landfilling of plastic with a cost-effective system that breaks down nonrecycled plastics into oil, while reusing some of the gas it produces to operate. To convert the plastics into oil, this new system first shreds them. The shreds are then entered into a reactor — which runs at about 400 degrees Celsius — where a catalyst helps degrade the plastics' long carbon chains. This produces a vapor that runs through a condenser, where it's made into oil. Much of the system's innovation is in its continuous operation (video). This company aims to produce more refined fuel that recyclers can immediately pump back into their recycling trucks, without the need for oil refineries. Currently, 2 trillion tons of plastic waste is sitting in U.S. landfills, so there is a huge demand for this technology.

Ocean garbage patches?

[Joe Gillian]

Why even bother with the landfills? There are massive garbage patches floating around in the oceans, the vast majority of which are plastics. If you can get a big enough tanker and implement this system on it, you could probably cut the amount of fuel needed even further - the tanker goes into a garbage patch, melts all the plastic down, keeps the oil, and uses some of it to get back to land. It would probably be more effective than loading fleets of trucks.

Oil - Plastic - Back to Oil?

[Irate Engineer]

I don't know how they define "cost effective", but since the plastic mostly came from oil in the first place, any energy expenditure to recover it is a net minus overall.

For an individual organization that can get a hold of a lot of landfill plastic cheap, this may be a win, but overall it is a fuel source with an energy return on investment (EROI) less than 1.

We're in trouble if we have to start resorting to this as an energy source. Deep trouble.

Re:Oil - Plastic - Back to Oil?

[Lab Rat Jason]

While I totally agree with this, I think it misses the point.

Assuming that plastic is provided for free (cities or landfills are already pulling plastic out via a separation step) then enough energy can be *recovered* from the plastic to power the recovery process with a net gain. The goal is not energy independence... it's prevention of non-biodegradable items making it into the landfill.

There was a story a few months ago about an MIT project [inhabitat.com] to float a collector out into the ocean to pick up plastic... maybe these two teams should get together.

Re:Ocean garbage patches?

[mlts]

Expanding on that, the US Navy (and I'm sure other nation's ship fleets) have excellent nuclear reactors. Even with current technology, thermal depolymerization wouldn't be that hard to do, especially near the Pacific Gyre with the large amount of floating waste available there. Then said ship either stays put, transferring the recovered crude to another vessel, or returns to harbor with useful resources.

Re:Ocean garbage patches?

[Smidge204]

Plus, you'd scoop up a lot more oceanic plant and animal life trying to extract that plastic material.

Actually, the critters might be a better fuel source than the plastics...
=Smidge=

2 trillion tons

[Bob the Super Hamste]

The statement that there is 2 trillion tons of plastic in land fills got me wondering how much oil actually goes into producing something. From what I can gather a barrel of oil weighs about 300 pounds so if there aren't any other external inputs into making plastics that would mean that about 13 trillion barrels of oil have been turned into plastic. This doesn't seem the least bit right given that under 2 trillion barrels of oil have been extracted and not all of that went into making plastic. So how much oil actually goes into making plastic and how much is other stuff is use?

This leads me to my next question which is how much of the weight of the plastic is turned into oil? If it is over 1/6 of it then we have the equivalent of more than all presently extracted oil in our land fills already.

Old Tech (Pyrolysis), Why it didn't sail

[retroworks]

Pyrolysis for "recycling" plastic waste into oil (or tire waste into oil) has been around since at least the 1990s. The main problems are 2: A) As Irate Engineer states, a polymer is an "added value" and deconstructing polymers back to oil always fails economically when actual recycling to like-polymers is available, and B) as Itzy says, the comparative value of returning it to fuel, vs. leaving it in an Municipal Solid Waste to energy facility and burning it, is small.

I read TFA and cannot figure out what differentiates this from the pyrolysis "waste investments" of the 1990s, none of which really sailed.