Slashdot Mirror
Purdue Makes Trash To Electricity Generator
musicon writes "A group of scientists at Purdue University have created a portable refinery that efficiently converts food, paper, and plastic trash into electricity. The machine, designed for the U.S. military, would allow soldiers in the field to convert waste into power. It could also have widespread civilian applications in the future. Researchers tested the first tactical biorefinery prototype in November and found that it produced approximately 90 percent more energy than it consumed."
Wake me when they invent the Flux Capacitor.
that in order to run the kit and transform the rubbish into a form that actually powers the generaor, they require x energy.
From the consumption of the next stage they get x + 90% energy, , otherwise it's a load of keech.
So, as we've all been commenting, this makes no sense. They simply must mean that it takes a certain amount of energy to power the thing. And that this energy (is it electric?) plus the mass being 'converted', will produce 90% more energy than it took to power the contraption.
Maybe I'm just rationalising outrageous claims or something, but I simply can't think of another way that this could make any sense.
Actually, they combine trash with ethanol to run a diesel engine ... The electricity produced is 90% higher than it would be with only ethanol. ... is what I understood :)
"No no, this thing needs more kick than that. It's nuclear - that's the only way I can generate the 1.21 gigawatts of energy I need."
Which part of this sentence:
don't you understand?Ignore this signature. By order.
This is described as energy returned on energy invested, or EROEI, of 1.9, which is not all that great. Ethanol from corn has a value of about 1.25, and that number is from its proponents. Anything below 1.0 is a lose.
US oil production has a value of about 3. That number declines over time; it was as high as 100 in the early days of oil production. (Look up "Spindletop") Saudi oil production has a value of about 10. Wind energy has a value of around 5. Solar power values depend on how long the equipment lasts; energy breakeven on solar cells happens some time around 5 years.
This seems to have two uses, both of which are, by them selves very amazing, together even more amazing:
1. It reduces garbage 30:1 and turns it into "ash" which seems to be a very easy thing to dispose of (especially at 1/30th of the amount)
2. It CREATES energy in the process.
As for the 90% thing, i believe they are saying that the input power would be what-ever power source you give it to turn the trash into electricity, I am pretty sure that the energy already in the trash is not counted in the input.
Just think, not only could you use your own garbage to power this thing, but just consider the fact that the one thing we have been trying to find a way to get rid of, and inadvertently stockpiling in land fills, can now be reduced by a factor of 30 and turned into electricity, just take a bunch of these to a local landfill and viola, less garbage and more electricity.
Any municipal government that does not take advantage of this (assuming it gets further developement) should be considered completely incompetent.
90% more energy than it consumes, eh. So all we have to do now is hook this thing up to, say, a pastry factory, a good supply of flour, fat, water and such, and there will be free, unlimited pastry and energy for everyone, assuming we feed the pastry scraps and uneaten pies, pasties and tarts back in the other end! :D
// cinn
If a lot of people have been working on a problem for a long time, you shouldn't expect a huge breakthrough. The reason I say these people are dreaming in technicolor is that they imagine that every restaurant will want one of these to process its food waste. The technology to do that has existed for a long time. The reason everyone isn't doing it is because it isn't economic.
People have been doing biodigesters since forever. The guys at Purdue haven't said they have found a magical new process. AFAICT, they are using the same process as everyone else. Ergo, they should have the same results as everyone else.
The other part of their system involves gassifying paper and plastic trash. That's another area where people have been working for a long time. It's the holy grail for municipal trash disposal. In fact, many municipalities are generating electricity from garbage but their plants are glorified incinerators not gas generators. In the early twentieth century many/most cities had gassification plants for coal. Now they are having to clean up the coal tar that was left behind to pollute the environment. The guys at Purdue didn't mention how nasty the waste product from their process might be. The people converting turkey guts to oil said that was one of the main problems they had to solve.
The guys in the story seem to have combined existing technologies and they haven't mentioned the known issues that the existing technologies suffer from. I don't expect to see one of these behind my local restaurant any time soon.
Not on a large scale, I think. This is likely to be a very polluting energy source. Hence it being described as "tactical." Good for emergency use - or for a desperately poor village that doesn't have any electricity to meet basic needs. But not to power your Plasma TV or Playstation.
... and then they built the supercollider.
The local landfill where I live, the Johnston landfill, here in Rhode Island, operates a methane recovery plant. This methane gas then flow through eleven twelve-cylinder turbocharged engines, to power a bank of generators.
This produces 15.3 megawatts of power. 1.3 megawatts is used to power the plant and landfill site. The remaining 14 megawatts is sold back to the grid, and provides power for 21,000 homes.
It's not quite 1.21 gigawatts, but it's still pretty cool.
RTFA they say the generator has to run off diesel oil for several hours to power the bioreactor/reformer. Once the components have had time to break the waste material down into ethanol, methane, and propane that gets funneled back into the generator that the net result is 90% additional output. If it was to take 10 liters of diesel to start the process, after using those 10 liters, and also burning the resultant fuels from the bioreactor/reformer it would be approximatly equal in electric output to having only used a plain old generator with 19 liters of diesel. In addition it reduces the trash input to aproximatly 1/30th of the volume in ash. It is bascially a mobile trash incenerator/generator that can be jumped started with diesel. Electrical plants that burn trash to produce electricty has been around for a long time. This sounds only slightly more efficent/environmentally friendly in that they use a bioreactor to produce ethonal from the biowastes, and use gasification techniques on the other types of trash instead of just plain burning all the trash together with a steam generator.
No matter is 'converted' to energy, it is only a chemical process to rearrange the the energy in the chemical bonds of the existant trash into a more useful form of energy(ie. electricity). Same as burning coal or any other fuel, the energy is released in the form of heat to provide work.
Would not be benificial to the average joe, however for the military I am guesing that it is a much better solution. We do not actually know how much more it weighs over a standard military generator and all the fuel that would be lugged around. In addition it reduces a units "signature" by removing the trash that would otherwise have to be hauled back out or destroyed in some other way. Also once it had been primed with several hours worth of diesel, it would be self supporting untill you either ran out of trash, or moved the unit somewhere and had to reprime it. I can see it reducing the logistics for diesel fuel and trash hauling for a military unit setting up a temporary base of operations.
In don't know, quite possibly. The point is that smaller generators are generally more polluting and less efficient. Being a diesel, and using waste-generated fuel, it probably generates more particulate pollution than your 2-stroke, but saves some fossil fuel and gets rid of some waste.
But in general, small generators suck, which is why they are only used for emergency and other limited applications.
No, for that, you'll have a centralized power plant outside the local dump, with all the pollution controls of any other power plant.But you'd probably do better by recycling the waste to create other materials, and using sources such as solar and wind for electricity generation. Electricity is not our only demand, materials are also needed. Better to re-use those solid materials when possible than to simply burn it for energy.
... and then they built the supercollider.
Are you perhaps not aware that military forces need large supplies of electricity, just as much as they need fuel for their tanks? That's an idiotic assumption to make. What makes you think this multi-ton diesel engine is going to only be equivalent of a small generator? I have no doubt it's aiming to replace the equally large generators, that are currently in-use by the US military. A tiny, lightweight generator isn't going to handle that kind of load. 190% is a hell of a lot. Half as many fuel shipments... Half as many people putting their lives on the line to truck in that fuel. Less fuel spent in the trucks (or planes) that actually hauls that fuel in. etc.
That's not even mentioning the perhaps equally large benefit of easy disposal of waste. Not having to ship it out to a dump in a war zone could save many lives, as well as even more fuel.
It sounds great. My only question is why they're using a diesel engine, when the military currently uses turbines, which are generally more fuel efficient, and require less maintenance.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
I, for one, fear the military applications of this...not like it wasn't possible before, but perhaps this might give some people ideas that would ultimately be used to kill people...
Uh, nevermind, I just read TFS.
Set your phasers on "funky"!
The reaction requires energy to fuel it, but the end result is 90% more than what you put into it. You can't just make a pile of trash and will it to create energy. Well you can, but uh...good luck with that.
Well, the article states it produced approximately 90 percent more energy than it consumed. Strictly read, this means that 1.9 units are produced per consumed energy unit, since totals are mentioned.
As such, the energy efficiency would be 100*(1-1/2.9)%=65,51%. I don't know the usual efficiency of this kind of generator, but 65% seems to be far too much (since combustion is used in the process).
Windows Vista runs my Sim City just fine!
There were a fairly large number of motor vehicles converted to wood gas during oil shortages in and after WWII.
FEMA wrote a book in 1989 on how to build your own. I think they had the foresight to realize that the U.S. military will eventually commandeer the available oil supplies again and we can try and figure out how to get to work burning garbage and the trees out of the backyard.
/* This is not a Hummer. */
I didn't say all of it. But it would be possible if humans actually cared enough to put any effort into sustainable energy. Why do you think it's not possible?
Yeah, good luck generating all the world's electricity from solar and wind. Let me know when you've finished that up...I didn't say all of it. But it would be possible if humans actually cared enough to put any effort into sustainable energy. Why do you think it's not possible?
Why the defeatist attitude? Humans have done many things that were deemed impossible only a short time ago. Like flying, or reaching the moon, or transmitting messages invisibly through the air. Solar and wind power are proven to work, we just lack the will to implement it properly. In many ways, powering everything from sustainable sources is much less "far out" than travelling into space was considered a short time ago. I guess we shouldn't bother trying, because you don't think it's possible?
... and then they built the supercollider.
Easy enough to do. What the article means is that for every joule the energy consumes it generates 1.9 joules. The joules it is consuming are not from the trash itself. It might be converting the trash at an efficiency of only 5% (making that number up, of course). It's just saying that it does, in fact, actually generate a net positive amount of energy while consuming the trash.
Somehow I suspect I haven't made this any clearer.
Consider the "Mr. Fusion" reference. We've created fusion generators that actually produce energy through fusion. However, so far, they've all produced less energy than it has actually required to run them, thus resulting in a net negative. All that 90% figure means is that this is a net positive.
Ben Hocking
Need a professional organizer?
We will never see this thing in action. ExxonMobil will buy the patent and keep it stored in very safe place!
Only globaly/universally. From the point of view of the (non-closed) system of the machine, it is giving out more energy than it is getting in.
Pointing at the mass and saying E=mc^2 is about as useful in this context as pointing to a lump of coal in your living room and saying that it can heat the room for the rest of your life. But it remains a lump of coal until you extract the energy. If you use less energy to ignite and burn the coal than it emits then you're ahead of the game, regardless of E=mc^2 or any other pointless appeals to thermodynamics.
I'm not saying you're wrong; I'm saying that your argument is irrelevant to a discussion of the usefulness of this device.
TWW
"Encyclopedia" is to "Wikipedia" what "Library" is to "Some people at a bus stop"
Not all materials are metals which can be relatively inexpensively melted back down and used with no negative effects in the next recycled generation. Paper recycling, for example, might be a cure worse than the disease.
The harsh chemicals used to remove the many and varied dyes from paper to be recycled are pretty terrible to begin with (And unlike bleaching regular pulp, you don't know what's going to be there, so you can't reformulate all that well), then you end up throwing the recovered pulp right back into the pulper anyway, so while there are likely some gains in energy, it's not necessarily friendly to the environment. Making matters worse, recycled paper seems to have less strength than original pulp.
In the end, you're making more use of toxic chemicals for a product of lower quality. I'm sure there are other similar materials where the friendly concept meets unfriendly process control reality.
It's been a long time.
2 stroke engines are far more polluting than either 4 stroke gas or diesel engines. They must mix their oil with their fuel, creating an exhaust that cannot be cleaned up (well) with catalytic converters or urea injection. This is why they have been all but banned in advanced industrialized nations.
One aspect of large scale solar fabrication is that heat management is easier. One only has to get silicon up to temperature but you don't have to keep it there with more energy in, so the 5 year figure you give is coming down dramatically. EROEI should end up near 40 on a single fabrication cycle, and potentially much higher depending on how recycling of the cells is handled during subsequent fabrication cycles. If the dopant gradiant is preserved through a cell-by-cell reannealing process to repair cosmic ray damage, then the energy requirements for recycling solar cells could be quite low compared to the initial fabrication requirements and thus boost the final EROEI over many recovery cycles. If not, one still saves on initial purification costs. Since we are considering a 40 year cycle, it is possible that silicon will be displaced by something more efficient, and it will become a nitch application, in which case determining the recycled EROEI will depend on how much silicon is retained in the energy generation sector.s -selling-solar.html
--
Happy days are here again: http://mdsolar.blogspot.com/2007/01/slashdot-user
I think you mis-understood the use of the term "tactical". Since the point of the generator was military, i think "tactical" referred to that it is portable and flexible relative to other waste-disposal means and/or energy-generating means. And on what basis do you say "likely to be a very polluting energy source"? The article linked said that the reduction of materials was a 30-1 ratio and that the EPA designated all the output materials (ash) "benign". So where do you get the conjecture "very" from? So it won't power my playstation, but it might power my block.
The outcome of any serious research can only be to make two questions grow where only one grew before. - Thorstein
On surplus food, we actually keep that stuff around as a hedge against crop failure. The current surplus is quite low: http://www.earth-policy.org/Indicators/Grain/index .htm while demand for this as a biofuel is growing: http://www.earth-policy.org/Updates/2007/Update63. htm. So, while we do need energy, s -selling-solar.html
our need for food seems a little more basic and setting up a competition between the two may be a big mistake.
--
Solar: It's not for dinner. http://mdsolar.blogspot.com/2007/01/slashdot-user
Can you.. you know... go in it?
Slashdot Burying Stories About Slashdot Media Owned
Did you RTFA? What leads you to believe that this will be a "very polluting energy source"?
From TFA:
"Much of the fuel the system combusts is carbon-neutral... Carbon-neutral fuels like ethanol do not cause an appreciable net increase in atmospheric levels of the greenhouse gas carbon dioxide. This is because the fuel releases carbon that has only recently been taken up by plants during photosynthesis, the process by which plants convert carbon dioxide to oxygen and sugars...
The machine produces a very small amount of its own waste, Warner said, mostly in the form of ash that the Environmental Protection Agency has designated as "benign," or non-hazardous. Any leftover materials from the bioreactor are put into the gasifier, which has to be emptied every two to three days.
"It's about enough to fill a regular sized trash bag, and it represents about a 30-to-1 volume reduction," Warner said."
So it burns clean AND it reduces the garbage that you put into it by a 30:1 ratio. Sounds pretty non-polluting to me. My only question is... why can't I have one of these things powering my house? I could dump my garbage into it every day and lower/eliminate my electric bill. Or maybe that's not practical. Maybe it requires an inordinately large amount of waste to run it. But still, they could build a bunch of these right next to a garbage dump and just start powering the city off of all our old garbage.
WATYF
2 stroke GASOLINE engines.
2 stroke diesel engines are extremely efficient. That's why they're used in extremely large engines. eg, The ones that power ships.
They're also less polluting than their gasoline counterparts.
2 stroke gasoline engines the oil is mixed with the fuel, this means you can use a gasoline 2 stroke in any orientation without oil starvation. (Weedeaters, Chainsaws, etc). They also have a very high power-weight ratio which makes them ideal for these applications.
2 stroke diesel engines have crankcase oil. Lubricating oil isn't mixed with fuel oil. Turbo/Super chargers force old air out.
At the same time 2 stroke diesel engines aren't something that are practical for small scale use. Some of these engines have cylinders that you can stand in. They run at well under 1000 RPM, even for max speed.
This product sounds like the best of all worlds: Start with waste biomatter, force decomposition using power from fuel oil, incinerate the rest, and eventually use the synthetic oil to power the generator. Would be extremely beneficial in a disaster area, such as after a huricaine, where you have plenty of building waste (wood) and an immediate need for local generation.
I, for one, welcome our garbage-converting overlords.
Don't tell me to get a life. I'm a gamer; I have LOTS of lives!
This will probably have fewcivilian applications. There are already co-generation plants that burn "trash". There just aren't any that you can put on a truck and move around. The usefulness to the military is obvious: reduce the load on the supply lines. It may have applications in disaster response as well.
The problem with the kind of waste this thing runs on isn't that we throw out the energy contained within it. It's that we throw out the matter contained in it. The matter still has to (a) come from some place and (b) go to some place. True, if the choice was landfilling anything we throw out and using co-generation, co-generation is a better alternative becuse it reduces the total energy consumption used to create/use/dispose of things a bit.
But you're still extracting the same amount of matter and throwing away the same amount of matter, just in different forms.
Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
Slashdot gets worse every day... Pipedot: News for nerds, without the corporate slant
Hmm... last I checked, we were trying our hardest to make sure 'interesting' states like Iran and North Korea weren't allowed to use nuclear power. So unless and until we feel comfortable giving everybody access to nuclear power (and not just the states we trust), nuclear power won't be a good solution.
I don't care if it's 90,000 hectares. That lake was not my doing.
sure Series 71 810 ftlbs @ 1200 rpm 290 hp governed at 2100 rpm (supercharged & turbocharged/aftercooled), that's some serious power. Detroit Diesel 2-Cycle Engine has video and sound clips of the various engines. Hummm a 2-71 would give you about 80 HP and one interesting and very chopper.
Apocalypse Cancelled, Sorry, No Ticket Refunds