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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."
I will not break the second law of thermodynamics
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.
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.
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.
OK, so it's 90% efficient, producing 190% of the fuel energy that's required to get it going.
;)
The question is, how much power is that? And does it merit the machine's use.
Thinking about it, it requires a couple of hours running on diesel to prime itself - so a rough guess, assuming its engine is similar to that of a small car, would be that it takes half a dozen to a dozen gallons of diesel to prime it.
In exchange, you get 190% of that in low grade fuel that its robust enough generator can process. So the equivalent energy output of maybe two dozen gallons of diesel but in a low enough grade form that you wouldn't want to put it near a regular engine.
The unit's described as about the size of a small van. Except it's likely denser so let's guess around five tons and it's cumbersome as all hell.
So, end result, you get the equivalent power output of maybe ten gallons of diesel, in a form you can't use to actually power anything much else, several hours later... in a form that likely consumes far more than that ten gallons or so to get it in to the field it's supposed to be used in.
It's cool as a concept but 190% of not a lot is still not a lot - and when the pain of getting it there and waiting for it outweighs the 90% of not a lot extra you get, it starts making more sense on efficiency grounds to stick with lugging a small generator and a couple of five gallon cans of a far more usable fuel.
In short: Just because you can do something, doesn't mean you should do it.
But I'm guessing the publicity will get them their second round funding, which is, I'm guessing, the real point of this.
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).
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.
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"
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
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 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.
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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.