Clean Energy From Garbage

[BigV]

rkzenrage:

Compare the economies of worldwide waste management to worldwide electricity production and consumption. You'll see that waste management is dwarfed by the energy economy. To me, the big story is the "any fuel - no pollution - energy production", not the novelty of being able to stoke the fires with Slim-Fast, concrete and fiberglass.

Burying the lead that way makes me... curious and a little suspicious. Perhaps that's too strong a word. Skeptical and interested to know more. There's got to be more, don't you agree?

Perhaps the most amazing part of the process is that it’s self-sustaining. Just like your toaster, Startech’s Plasma Converter draws its power from the electrical grid to get started. The initial voltage is about equal to the zap from a police stun gun. But once the cycle is under way, the 2,200˚F syngas is fed into a cooling system, generating steam that drives turbines to produce electricity. About two thirds of the power is siphoned off to run the converter; the rest can be used on-site for heating or electricity, or sold back to the utility grid. “Even a blackout would not stop the operation of the facility,” Longo says.

Once the system was under way it would feed the power back into it's own grid.
As I stated in my last post. Even it if only self sustained and got rid of garbage that would have created toxic landfills we should be dancing in the streets.

[Kitsune]

Originally Posted by BigV

So why isn't this the freakin Next Big Thing? What's the catch? Assuming no pollutants are produced or emitted based on what goes in, and that anything can be used as fuel, why are dirty coal and remote expensive dangerous oil still tops of the pops?

I'm not deliberately being obtuse (it's a character flaw, you'll just have to endure it), I just feel that it doesn't all pencil out, based on my limited understanding of the inputs.

It doesn't all pencil out because it is a PopSci article and leaves an incredible amount to the imagination. A significant portion of the process is omitted and I feel the tone of the article, "we put trash in and nothing but energy and flowers comes out", is a bit misleading.

Getting from Syngas to ethanol isn't a simple or very efficient process. It is also cheaper, easier, and more efficient to simply pull natural gas (double the energy density of Syngas) from the ground than it is to use Syngas.

Regardless, all of these methods still generate quite a lot of greenhouse gases, so viewing this as a "green fuel" isn't entirely straight. Burning municipal waste to generate electricity is especially difficult and others have tried it:

Two similar facilities run by different companies in Australia and Germany closed after failing to meet emissions standards.

...

Dioxin emissions are possible from plasma arcs when chlorine is present. Process gas cleanup is necessary when gasifying waste streams such as municipal waste streams known to contain heavy metals, chlorine/fluorine, sulfur, etc.

In 2004, the city of Honolulu considered a plasma arc/torch proposal for processing municipal solid waste. The city's Department of Environmental Services evaluated the plasma process and found that using plasma arc/torch technology would significantly boost waste disposal costs (High Electricity inputs) without accurately considering environmental advantages.

This process is not perfectly clean nor efficient by any measure.

An interesting note on the high temperatures and the metal containment shell:

One other issue regarding plasma systems is in the life of their liners. The liner is an important aspect of separating the high interior temperatures of the plasma system from the [metal] shell of the plasma container. Liners are highly susceptible to both chlorine attack and to local variabilities in [high] temperatures - both of which would be found with typical municipal waste systems, and are not likely to last more than a year in service.

Refinement of this process might make it feasible in the future, but even then this comes down to burning waste for fuel. Mercury, lead, and other toxic elements are still going to be byproducts of municipal trash burning unless the input is closely monitored and sorted. Chances are high that requirement makes this far too costly.

[BigV]

Originally Posted by Kitsune

It doesn't all pencil out because it is a PopSci article and leaves an incredible amount to the imagination. A significant portion of the process is omitted and I feel the tone of the article, "we put trash in and nothing but energy and flowers comes out", is a bit misleading.

Bullseye. And you do have a flair for humor. Very funny.

[HungLikeJesus]

Originally Posted by glatt

Pretty cool. It's not completely clean, of course. When the fuels are burned to make electricity, there is some pollution.

They've been talking about this for years. It's time for some cities to implement it.

I posted about another company's similar process a few years ago.

Here's an update on the Changing World Technologies TDP: http://i-r-squared.blogspot.com/2007...s-reality.html

It's a little long. Here's a short excerpt:

The Bloom Comes off the Rose

So, where does the technology stand today? How far off were those $8 or $15/bbl costs estimates? After all they had run the pilot plants. They had "done so much testing in Philadelphia", they "already know the costs." Turns out they didn't:

Reports from 2005 summarized some economic setbacks which the Carthage plant encountered since its planning stages. It was thought that concern over mad cow disease would prevent the use of turkey waste and other animal products as cattle feed, and thus this waste would be free. As it turns out, turkey waste may still be used as feed in the United States, so that the facility must purchase that feed stock at a cost of $30 to $40 per ton, adding $15 to $20 per barrel to the cost of the oil. Final cost, as of January 2005, was $80/barrel ($1.90/gal).

There's a lot more.

If you're still interested, there's a follow-up to that article here: http://i-r-squared.blogspot.com/sear...20Technologies

[glatt]

Cool. So the technology was proven, but it just wasn't as economical as they hoped due to market reasons.

[HungLikeJesus]

It seems that the technology works, it just wasn't as efficient as they projected (I don't know how they did all the pilot tests without finding that), plus the economics were highly optimistic.

Also, the person in charge is a salesman and not an engineer, and keeps using known-bad data.

I work in this field and see this, unfortunately, too often.