Trash problem? No, it's a Power Solution!

[rhoenix]

Cheesy thread title, I know, but I couldn't help it. I think this is clever.

Recently St. Lucie County in Florida announced that it has teamed up with Geoplasma to develop the United States’ first plasma gasification plant. The plant will use super-hot 10,000 degree fahrenheit plasma to effectively vaporize 1,500 tons of trash each day, which in turn spins turbines to generate 60MW of electricity - enough to power 50,000 homes! Cutting down on landfill waste while generating energy is a pretty win-win proposition, and the plant will also be able to melt down inorganic materials to be reused for other applications, such as in roadbed and heavy construction.

Plasma gasification was invented by NASA 40 years ago to recreate re-entry temperatures for spacecraft. The process uses an electrical arc to heat up gas to form Plasma, which in turn breaks down waste. The intense heat of the plasma gasifies municipal waste, converting it into “syngas”, which is then cleaned to remove volatile elements. Next, the vapor is sent through a turbine to generate electricity.

Plasma Gasification plants generate much less emissions than standard waste incineration plants, and also cuts down on landfills, which are the US’s largest human caused producer of methane gas. No word yet on the cost-effectiveness of maintaining such plants (all that plasma gas and filtration must be expensive), but if Geoplasma is able to make the process more efficient they could simultaneously solve our landfill problems while generating a significant amount of energy.

There are many pictures on the site, which does make up for a somewhat sparse article. However, I feel this idea has great potential, and I'd like to see where this goes.

Additional links from the article:
Geoplasma - the company responsible
[url=http://en.wikipedia.org/wiki/Plasma_arc_waste_disposal]Wikipedia article on Plasma Arc Waste Disposal

[rhoenix]

Yeah, should've previewed, I know.

Additional links from the article:
Geoplasma - the company responsible
Wikipedia article on Plasma Arc Waste Disposal

[Samuel]

We have incinerated trash since... Roman times? And got power from it since the 70s.

This is just a more efficient upgrade that use its waste heat to melt stuff down. Which is admitadly an improvement, but probably insanely expensive.

[NoXion]

I wonder what the trade-off is between the energy needed to produce the plasma arc and the energy produced by the spinning turbines - I would have thought that there wouldn't be a net energy gain.

[Kuroneko]

I wonder what the trade-off is between the energy needed to produce the plasma arc and the energy produced by the spinning turbines ...

Quantitatively? I wonder as well, and also about how clean it is.

- I would have thought that there wouldn't be a net energy gain.

You're right--imply atomizing it and passing it through turbines shouldn't give a net energy gain. However, depending on what the end results are, there could be; i.e., if after atomization the atoms recombine to form other compounds, especially if they are subsequently burned. The gasification itself would be just a step to remove pollutants.

[Ted C]

Does no one else see a thermodynamic problem, here?

Surely the amount of energy being thrown into that trash to vaporize it is far more than they're getting back out when the plasma turns the turbine.

[NoXion]

Does no one else see a thermodynamic problem, here?

Surely the amount of energy being thrown into that trash to vaporize it is far more than they're getting back out when the plasma turns the turbine.

Well, burning waste does produce energy. Somebody far more qualified than I am would have to do the mathematics to be sure of it.

[SCRawl]

Does no one else see a thermodynamic problem, here?

Surely the amount of energy being thrown into that trash to vaporize it is far more than they're getting back out when the plasma turns the turbine.

Well, burning waste does produce energy. Somebody far more qualified than I am would have to do the mathematics to be sure of it.

Yeah, but according to the OP they're not just burning it -- they're turning it into vapour. That change of state has an energy cost associated with it.

In any case, it would appear as though they're vapourizing the trash in order to diminish or eliminate pollutants in the output stream, and taking advantage of the fact that this process releases some energy. The energy that you'd get out wouldn't be as much as is being put in, but it's better than just releasing it for a complete loss. Long story short, it ends up costing a little less (net) energy to get rid of the trash by putting some turbines on the back end.

[Beowulf]

Dudes, they're burning the syngas in gas turbines. That's where the power comes from. Input of plant: lots of trash. Output: some metal wastes, a shitload of CO2, and power.

[Singular Intellect]

There's no violation of Thermodynamics when one considers that the trash itself is argueably 'fuel'.

It's merely a matter of figuring out the efficiency of this system.

[Darth Tanner]

Seems like an incredibly expensive and needlessly complex way of building a waste incinerator. Plus I have doubts on how green it actually is seeing as the gas has to be filtered for 'volatile elements'. If your going to go to all that trouble and expense why not simply build a standard incinerator with carbon capture technology. Without any cost analysis it’s impossible to say if the idea has any merit or is simply media hype over hi-tech magical solutions.

[Molyneux]

Yet another proof of the old adage: everything is better with fire.

[Kuroneko]

Does no one else see a thermodynamic problem, here?

See the post directly above yours.

Surely the amount of energy being thrown into that trash to vaporize it is far more than they're getting back out when the plasma turns the turbine.

That would be true if that's all that happens in the plant, since atomization and ionization have an energy cost. The latter is fully recoverable through recombination, although of course one can't get it back completely in terms of useful (non-thermal) energy. However, the atoms are themselves reactive, and as they associate into compounds, there is an energy gain because the chemical binding energy is negative--since they will in general be different compounds, this would at least partially offset the atomization costs (perhaps even be greater, depending on the initial compounds). If other elements are brought in (e.g., the resulting compounds are themselves burned), the setup begins to look functionally like a high-tech incinerator that happens to filter the waste before burning it rather than after.

Seems like an incredibly expensive and needlessly complex way of building a waste incinerator. Plus I have doubts on how green it actually is seeing as the gas has to be filtered for 'volatile elements'.

It's potentially very clean--this method is sometimes used for disposal of chemical weapons. The facility cost is offset by selling the electricity; however, whether the planet can stay clean and still generate enough electrical power to be economically viable is a good question.

[Samuel]

Yet another proof of the old adage: everything is better with fire.

Technically we have finally found a use for plasma weaponry

Still, I'm wondering exactly what they are going to be putting into it that they can reclaim large amounts of metal. Anyone know?

[Dave]

Still, I'm wondering exactly what they are going to be putting into it that they can reclaim large amounts of metal. Anyone know?

What do you find in a typical landfill/dump? You could run rebar concrete through the machine, for all it cares. I think the large amount of metal they're claiming would be due to the sheer amount of stuff you run through it. Eventually you will get metals in the slag.

Put another way, household trash could include aluminum cans, tin cans (e.g. from preserved foodstuffs), spare change that got thrown away, staples and so on. Add that to the volume of trash you run through this, and you might get a decent amount of metals in the slag.

[Erik von Nein]

Yeah, this would be good for all the rare earth metals that get used in electronic devices like cell phones and such. They're apparently starting to see the amount recovered from mining decrease, coming up soon to a "peak earth metals" of sorts. There's quite a lot buried in landfills, and this process may end up being cheaper, depending on how rare these rare earth metals get.

[Sea Skimmer]

Amusingly in ordered to be ‘green’ the latest USN warships are being fitted with this kind of system to burn up trash, and avoid dumping it over the side. The USN… Green until the first PLO depot gets on the target list.

[rhoenix]

Article update, courtesy of Popular Science:

Trash is a stinky topic. With 130 million tons of it hitting landfills annually, it is the nation's largest human-caused producer of methane gas. And now, residents in Florida's St. Lucie County are turning that stench to gold. Or at least to gas. The county has paired up with Atlanta-based company Geoplasma to implement a plasma gasification plant. Originally created by NASA 40 years ago (so that spacecrafts could maintain their reentry temperatures), plasma gasification is now a useful waste treatment technology process that uses an electrical arc to break down waste using high temperatures. [Ed note: for a comprehensive background check out last year's "The Prophet of Garbage"] However, few plants exist in the world, let alone in the U.S.—and most for industrial purposes

That is about to change for those in Florida. Geoplasma is developing a plant for St. Lucie County to vaporize 1,500 tons of trash a day into pressurized gas, which will then use turbines to generate 60MW, enough electricity for 50,000 homes. Although the process uses temperatures of up to 10,000 degrees Fahrenheit, emissions from plasma gasification plants are considerably lower than standard waste incineration plants. Furthermore, nothing in the process goes to waste—inorganic trash, such as metals, condense in the process and can be used for roadbeds and heavy construction, and even the steam from the high temperatures can be used to generate more electricity. The plant is expected to go live by 2011.

Not that much more information, but still looking encouraging thus far.