Slashdot Mirror
Plasma Plants Vaporize Trash While Creating Energy
Jason Sahler writes "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!"
How much energy is used in generating that 10,000 degree plasma, hmm? Less than what it'll output by incinerating trash? I'd like to see that.
It's apparently self sustaining.
Want to improve your Karma? Instead of "Post Anonymously", try the "Post Humously" option.
What could possibly go wrong? I dunno, lots of things. The whole place could catch on fire. Or someone could be electrocuted by equipment on site. Or someone has an accident on a ladder and falls and hurts himself. Or gets in a car crash on the way to work. (That's probably the most dangerous risk right there!)
What, you wanted something exotic? 5,600 degrees C is weak. A lightning bolt can hit 30,000 Kelvin. Somehow the Earth escapes destruction though!
The World Wide Web is dying. Soon, we shall have only the Internet.
This page explanis the technology:
plasmawastedisposal.com
Their web site just screams "vaporware". In fact, the useful-scale project has been cancelled, and only a small "demonstration plant" will be built.
The real questions about this are 1) do they really get out more energy than they put in, and 2) how much processing of the exhaust gases is required? Westinghoue Plasma Corporation (which, sadly, has little to do with Westinghouse) claims that 1000 tonnes (metric?) of solid waste produces the energy equivalent of 1 (one) barrel of oil. So this isn't a big energy producer. Ordinary waste-to-energy plants do better than that, but don't burn as clean as a plasma arc.
The other problem is what comes out. Organic compounds are literally blasted apart into atoms at those temperatures, so it deals with biowaste just fine. CO2 comes out, of course. NOx, maybe. Everything heavier (metals, etc.) is supposed to come out as a "molten slag" suitable for cement aggregate. Not sure what the cement industry thinks of this. They're usually quite picky about what's allowed in cement aggregate. Some contaminants interfere with the chemistry of concrete curing and make bad concrete. It might be good for filling in swamps and such.
A high temperature incinerator was proposed for Victoria, Australia. The "who will think of the children" shot it down and we still have landfill. Here is a link: http://homepage.mac.com/herinst/sbeder/incinerator2.html
also google for "high temperature incinerator" +victoria
it is only after a long journey that you know the strength of the horse.
While I'm skeptical that this is net-energy-positive, it isn't a closed system. The trash represents an additional energy source. In fact, I think it's fair to say that if this system doesn't produce more electricity than it uses, it's a monumental waste of waste-energy. This makes sense only if they can produce more electricity (after subtracting electricity input) than a simple steam plant could from the same trash input. It really isn't all that helpful to spend more energy to produce less energy.
What changed under Obama? Nothing Good
Self-sustaining != Self-starting
It is self sustaining in the way your car's electrical system is: It provides enough juice to start the engine, which recharges your battery and runs your radio/lights/cigarette lighter.
The standard conversion is actually closer to 1MW per 1000 homes (1kW per home) on average. When you're running the drier or the electric stove, sure it's a lot more. But if you're just watching TV with a few lights on it is probably closer to a 400W load. The big problem happens around 4:45PM. Businesses are still open, but people have gone home and turned all the lights on. So the load usually peaks around that time. Obviously the grid has more capacity than 1kW per home, but on average this is about the average usage. What does your monthly bill say? If it is around 650-800 kW-hr then you only use about 1kW on average. (I have worked for a large utility and now work for a turbine manufacturer)
Even those who arrange and design shrubberies are under considerable economic stress at this period in history.
Burning garbage creates highly toxic materials, like dioxin. So does gasifying the garbage, apparently, according to this position paper. The article doesn't address this issue.
There is a reasoned and informative opposition to this plant. By ignoring this opposition, the featured article reads like a PR piece.
This process will NOT "create" energy.
seriously. at best this sounds like a marginally novel take on cogeneration.
2 1337 4 u!
One of the problems we are going to face Real Soon, is "Peak Oil". Another is funnily enough "Peak Soil"[1] and yet another is too much CO2 in the atmosphere.
A plasma turns everything into the basic element and from there to the lowest energy state, so yeah we get plenty of energy out, but it doesn't help so much with peak oil, peak earth or too much co2 in the atmosphere.
Some of the benefits of pyrolysis however:
1: Energy is produced.
2: Liquid fuels can be produced for transport.
3: Biochar/Agrichar byproducts can be used to improve agricultural soils.
The biochar byproduct can make the process carbon negative.
[1] Degradation of agricultural soils.
Deleted
I do a LOT of work on refuse disposal options, principally for the UK food industry. From the top of my head:- Use of plasma for waste disposal, this is not new, there was a french system proposed a few years ago for disposal of medical waste, looks like pathogens get a bit uncomfortable at tempertaures of several thousands of C. (this is from a New Scientist article, unable to refernce at the moment) The article references syngas, this is usually derived from anaerobic heating (>600oC) of organic matter and was used to make town gas from coal for street lighting. This can be used on food wastes (there is a huge amount in the UK) and run through the Fischer Troupe process to make petrol etc. The downsides :-
High pressure - increases capital costs geometrically with scale.
Chemical plant - NIMBYS do not like them (what a suprise. )
Process does not like water - food waste is 60% water.
Energy intensive (work out how much energy is needed to volitise teh 5 Million tonnes of food waste generated in the UK each year - its a lot).
The upsides :-
Established and proven technology.
Lots of very cheap raw material.
Use the energy content of the raw material to dry and vaporise the residue (an approx. 30% energy cost penalty - but the source is cheap)
Will consume anything organic, so mixed and contaminated food waste not a problem - will accomodate glass and metal contaminants
Best of all, as the plant scales down, there is an exponential decrease in the wall thickness needed for pipework etc. needed, so cost decreases at the same rate. You could have a pallet sized unit getting through a tonne per hour (Perdue University have done this for cleaning up waste at militry bases) for a very worthwhile cost. Note in the UK, landfill costs are now in the region of £60/tonne and rising by £8/year due to land fill tax. God help you if you have to render high risk material prior to landfill, your are then looking at a cost of about £100/tonne. A £25M t/o food plant will easily generate 2000 tonnes of food waste per year. This is significant, given most food manufacturers are operating on net margins in the very low single figures. A back of the metaphorical fag packet calculation showed that we could generate enough petrol from such sources in the UK to meet our commitment to add 5% from renewables to our petrol every year.
Just release the carbon into the air, so the trees can use it. Or do we hate trees now?
Also, rotting garbage turns into methane and CO2. If you didn't know that.
“Common sense is not so common.” — Voltaire
Aren't there plenty of simple molecules and elements that are toxic, not just metals?
Most elements are only toxic when part of specific molecules. They're toxic because they're highly reactive, and reaction means they're going to a lower energy state. At some point, the energy state should become low enough that they're pretty inert.
Ofcourse stuff that's toxic because of radioactivity instead of chemical properties is a different matter. But if you vaporize it and mix it with lots of inert material, you should end up with something that's about as radioactive as sea water.
We should focus on reuse and recycling, not vaporization.
Of course, but recycling isn't always practical.
From http://biowaste.blogspot.com/2007/01/geoplasma-answers-trash-vaporization.html:
1. Question: How much energy does the plasma-arc use?
Answer: The plasma-arc facility uses approximately 40 megawatts of energy per hour. This is approximately one-quarter of the total output of hourly energy received from MSW.
2. Question: What will be the source of the plasma-arc energy?
Answer: The facility will receive its energy from its total output. For St. Lucie, it is expected that the 3,000 tons of MSW processed per day will create 160 megawatts of energy per hour. As stated previously, 40 megawatts will be used to power the facility and the remaining 120 megawatts will be sold to an Electric Utility.
3. Question: What does the energy source emit?
Answer: See question 5.
4. Question: Is the high heat of the plasma-arc being captured and utilized?
Answer: Because of the nature of a closed-loop system the heat will be captured and utilized both in the plasma gasification process and later in the production of steam.
5. Question: How are they going to combust the syngas to keep the emissions low?
Answer: There is no combustion during the gasification process. The Plasma-arc gasification process is a chemical reduction process that converts MSW from its original state to a glass-like aggregate solid at the bottom, and a synthetic fuel gas, also known as syngas, at the top.
Once gasification is over, the syngas is cleaned in a multi-step process, bringing it to levels near natural gas cleanliness. It is then compressed before being used as fuel for a gas turbine.
The gas turbine for this process is a modified natural gas turbine that mixes the cleaned syngas with air from the atmosphere, combusts the mixture and sends the hot gases through a turbine. The turbine spins an electric generator to produce electricity. The discharged hot gases are then passed through a heat recovery steam generator to produce more steam and to cool the hot gases. The cooler exhaust gases are then discharged into the atmosphere via a stack.
Emissions from this process are very similar to natural gas combined cycle plants which are considered to be 'clean' and are located and permitted all over the U.S., and for that matter the whole world.
This sig is intentionally left blank.
Some simple facts to explain why it works:
1. Garbage contains a lot of energy (hydrocarbons in plastics, rubber, food, paper, etc).
2. Garbage contains some metals (aluminum, iron, copper, zinc, nickle, etc).
3. Garbage contains a far amount of inert material (earth, ceramics, etc).
So, you run everything through a big grinder, feed the dust to an electric torch which turns it into plasma, which of course breaks all those fancy compounds down into simpler elements:
1. Hydrocarbon gas - synthgas (methane like stuff).
2. Steam -- the water trapped in plant materials mostly (grass clippings, banana peals, stuff like that).
3. Metallic gas - which you can optionally separate by element if you have the right equipment.
4. Slag - inert silica mostly, mixed with other crud (which you can use as building materials).
Important thing to remember is the electric torch doesn't burn the garbage -- burning is inefficient and pointless. You want to separate all the various elements so you can make efficient use of them:
1. The hydrocarbons are pull off as synthgas, which you use some of to run a generator to power the torch and the surplus you sell to a conventional natural gas power planet for profit!
2. The steam which you separate and sell to as heat for commercial or residential use.
3. The metals you sell as scrap -- either high or low quality depending on your ability to separate the elements from the plasma.
4. The silica slag you can mold into pavers while it's still hot, or spin into a ceramic like wool as insulation, or into black pebbles as ground cover or whatnot.
The process has a number of advantages:
1. It is profitable -- it produces more energy than it consumes.
2. It's low tech -- you can set up the facility inside the garbage dump and avoid shipping the garbage around.
3. It sterile -- it consumes medical waste, contaminated material, toxic junk as readily as normal waste and it reduces it all to simple lemony fresh clean compounds (makes the birds sing). You can't feed it radioactive material obviously, as that would foul up the works.
4. It's happy -- converts garbage back into useful things.
Biggest obstacle has been the patents on the process which expired a year or two ago. Rejoice, garbage is the new valuable resource!
Plasco has had a Plasma gasification pilot that has been running for a while here in Ottawa. I seem to recall over the summer news was that it produced less energy than hoped, but was still self supporting.
Links:
http://www.plascoenergygroup.com/
Yes, they seperate the bad stuff out. From TFA:
The intense heat of the plasma gasifies municipal waste, converting it into "syngas", which is then cleaned to remove volatile elements.
This process is not new -- it's been done elsewhere (Japan, Canada, UK) before. It works. They know what they're doing.
Slashdotted... mirror here: Plasma Plants Will Vaporize Trash While Generating Energy
Your post advocates a
.)
[ ] physical [ ] legislative [ ] market-based [ ] chemical
approach to waste management. Your idea will not work. Here is why it won't work. (One or more of the following may apply to your particular idea, and it may have other flaws
[x] it violates the First Law of Thermodynamics
[ ] it violates the Second Law of Thermodynamics
[x] catalysts are NOT magic
Specifically, your plan fails to account for
[x] the energy needed to accomplish your simple tranformation
[x] it requires more non-renewable energy inputs than the renewable energy produced by it.
[ ] It requires immediate cooperation from the entire world all at once.
[ ] People will cheat.
[ ] It requires the population to act contrary to self-interest.
[x] Extensive existing infrastructure.
[ ] Problems storing power.
[ ] Inefficient power transport systems.
[ ] Variable weather.
[x] Rich and powerful industries and lobby groups who stand to lose money.
[ ] Politicians who know nothing about science.
[ ] It uses Nuclear power, and that scares a large number of people who don't get the science behind it.
[x] It uses science, and that scares a large number of people who don't get the science behind it.
In summary:
[ ] Nice try, but it won't actually work.
[x] You're a scammer trying to blind investers with psuedoscience.
[ ] You're completely nuts.
The process doesn't break down atoms (that would be fission) it only breaks the molecular bonds. All elements would be preserved for reuse.
In Soviet Russia meme tires of you!