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The reactor is a relatively tiny 2-foot-high apparatus of tubes and wires that creates hydrogen from corn-based ethanol. A fuel cell, which acts like a battery, then generates power.

"This points to a way to make renewable hydrogen that may be economical and available," said Lanny Schmidt, a chemical engineer who led the study. The work was outlined in Friday's issue of the journal Science.

Hydrogen power itself is hardly a new idea. Hydrogen fuel cells already propel experimental vehicles and supply power for some buildings. NASA has used them on spacecraft for decades.

But hydrogen is expensive to make and uses fossil fuels. The researchers say their reactor will produce hydrogen exclusively from ethanol and do it cheaply enough so people can buy hydrogen fuel cells for personal use.

They also believe their technology could be used to convert ethanol to hydrogen at fuel stations when cars that run solely on hydrogen enter the mass market.

Hydrogen does not emit any pollution or greenhouse gases. But unlike oil or coal, hydrogen must be produced -- there are no natural stores of it waiting to be pumped or dug out of the ground.

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Suncor to build plant?

The only question is, how much corn or other biomass would be needed to produce the fuel our society needs? I imagine we could do it, but does anyone know?

[ 13 February 2004: Message edited by: Mike Keenan ]

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As spake by Mike Keenan:
Electrolysis would require an awful lot of electricity and (if sea water were used) would also produce chlorine as a byproduct.

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(Niglet)

This is actually only true for salt water. Fresh water would not liberate chlorine in the electrolysis, but due to lack of ready ions, would also mean a helluva slow electrolysis.

(/Niglet)

Ideally fresh water would be used, spiked with a tiny amount of, say, sodium nitrate, or some other salt which provides the ready flow of ions, but which doesn't participate in the electrolysis itself.

Megolookupsomereductionpotentialsnow.

[ 14 February 2004: Message edited by: DrConway ]

However, what are the waste products? I am guessing that the hydrogen comes from the hydroxyl radical on the ethane so the other products are ethane and oxygen.

As long as the oxygen concentration stays low enough to obviate combustion risks that part shouldn't be a problem.

I suspect ethane is a good infrared block but might be too heavy to float high enough in the atmosphere to be a good (bad?) greenhouse gas. The trick then is to avoid suffocating concentrations in basements. On an industrial level it should get captured as petrochemical feedstock.

One tthing about all this is that the energy density is low so the total volumes will be quite high.

Each would have its advantages. Breaking the alcohol down all the way would be good in that you'd get much more hydrogen from a given amount of alcohol, but would have the drawback of not producing the useful byproducts that Gir mentions, and would be CO2-neutral, whereas if ethylene is produced and used to make plastics, then you'd have a net removal of CO2 from the air, which we could definitely use right now.

So does anyone know how this thing actually works?

Update (added a few minutes later when I decided to exert the effort to actually look it up) According to this link the byproducts are CO2 and "minor products". It says that it produces 4 hydrogen molecules per ethanol molecule; that presumably means that 2 atoms have to come from water, unless they're being sloppy and meant 4 hydrogen atoms (i.e. 2 molecules) per ethanol molecule. I presume the "minor products" mentioned might include carbon monoxide, acetaldehyde, and the like, though the article doesn't elaborate.

[ 14 February 2004: Message edited by: Mike Keenan ]

Higher concentrations have to be gotten by distillation.

And yeah, TPaine brings up an important point. This method of producing ethanol is horribly inefficient, and companies like Archer Daniels Midland that produce this stuff on an industrial scale get huge subsidies from the US Government because otherwise they can't make a profit on the sale of the stuff.

On the other hand, I do see a big future for electric cars; and for solar generation of electricity. The amount of light that falls on Lake Superior in a single day contains the energy needed to heat all North American homes for a year. (don't quote me, I heard this on the radio) The biggest waste of energy is idling internal combustion engines; most of which happens while stopped in traffic. Electric motors don't idle.

The second biggest waste of energy is long distance transmission. (Or maybe hauling crude across the oceans.) We are going to have to have power generation closer to home. Having a dam in northern Canada supplying electricity to California is extremely wasteful and it should stop. (Besides, Californians don't pay their hydro bills.)

As for electric cars, if you mean battery electric cars, there are other problems to consider. Most storage batteries, even setting aside their size and weight, contain heavy metals (lead, cadmium, etc) and thus pose a serious disposal problem when they lose the ability to hold a charge. Of course, if they could be recycled efficiently enough, that would not be a problem. But pure electric cars don't do well in a climate like ours.

My suggestion for the short term- biodiesel. Like ethanol, it can be produced from a number of crops (I heard a story on CBC last year about a guy who runs his BMW, without modification, on biodiesel that he makes from used french fry oil). The idling problem is easily overcome- indeed it already has been overcome by Toyota and Honda in the hybrid cars that they've been selling for the last couple of years. And you don't have to limit yourself to piston engines, either- gas turbines will also run fine on the stuff (or indeed on gasoline, ethanol, methanol, kerosene, or hydrogen- great if you don't want to have to come out with a new engine design every few years until a standard is achieved). Gas turbines work fine in hybrids (indeed, better than they do on their own) and the modern ones run very cleanly. The main problem is that they're more expensive to make and maintain than piston engines (gas or diesel). Of course hybrid cars still use storage batteries, but they don't need such large batteries, so the problems of size, weight, and disposal are much less serious. As an aside, you could put solar panels on the car roof, which might significantly improve fuel economy since the engine has to do less work to power the motor and charge the batteries.

As for nuclear power, I assume you mean fission, because we haven't made a practical fusion reactor yet. I still have serious reservations about this, since the waste disposal problem has yet to be solved (and may never be solved) and any reactor with an acceptable level of safety from accidents is extremely expensive to maintain (most nuclear reactors require large subsidies to keep running). It might be a good energy source to use on the Moon, but not on Earth. That said, fission energy just might be the lesser evil compared to fossil fuels, for the short term anyway.

On the other hand, if fusion can be made practical, it holds great promise- its only byproducts are helium and heat. I am, however, curious about the climatic effects of releasing helium in large amounts into the atmosphere. I know it's chemically inert, of course, but would it have an effect on the greenhouse effect (one way or another)? Or would it escape to space because it's so light? I presume the answer is known by someone, but I've never seen any commentary on this.

[ 14 February 2004: Message edited by: Mike Keenan ]

The main danger from fusion power is the high neutron flux it generates, which can degrade the reactor vessel over time. Think of these high-energy neutrons as being like billiard balls smacking a large concrete wall. Over time you will start seeing small dents and cracks in the wall.

Same principle, although some neutrons will fly through the "wall".

Some fusion reactions do not generate a neutron flux, but do generate a high gamma ray flux, which can also cause fatiguing of the reactor vessel walls, and in much the same way as neutron fatigue operates.

Not to say that these are insurmountable problems, but it's not as simple as just going "BAMMO! Smash two protons together!"

As for nuclear fission, the main problem with the waste is that there are comparatively few practical uses for radioactive isotopes. In radiochemistry and radiobiology, the primary isotopes of practical interest are tritium (hydrogen-3), carbon-14 and phosphorus-32. Chlorine-36 is used to a lesser extent - and all four of those are primarily used in tracing metabolic pathways in plants or animals.

Americium-241 is used in smoke detectors because it's a comparatively long-lived alpha source that still degrades to nothing in a respectable time interval, rather than remaining radioactive for billions of years.

Technetium isotopes find uses in medical imaging, primarily.

There are no known practical uses for Promethium or most of the actinides (aside from thorium, uranium and plutonium for obvious reasons).

The majority of radioactive isotopes, however, produced in a fission reactor, are simply waste products. A minority of stable isotopes DO get produced in fission reactions but this is the exception and not the rule.

However, there is a fella who thinks he's found a solution to the problem. What's makes radioactive isotopes unstable? Their out-of-whack neutron-to-proton ratios (or, in the case of elements beyond bismuth, the lack of sufficient nuclear binding force to hold the nucleus together). Normally, you have to let them disintegrate on their own, taking their sweet time doing it.

Solution: Aim a beam of protons at the suckers and blast off some excess neutrons. Hello, stable isotope formation.

1. The nuclei are surrounded by a bunch of electron shells, which will tend to repel the protons before they hit the nucleus. I guess you could ionize the hell out of the waste products, but that would take a lot of energy.

2. Making a beam of protons to do that would take a pretty decent particle accelerator, I imagine. This too would take a lot of energy.

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Originally posted by Mike Keenan:
Very interesting. I'd never heard of that before, though it makes sense. Two problems come to mind, however.

1. The nuclei are surrounded by a bunch of electron shells, which will tend to repel the protons before they hit the nucleus. I guess you could ionize the hell out of the waste products, but that would take a lot of energy.

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Electrons are negatively charged. Protons are positively charged. There would not be repulsion, but attraction.

You are correct that a problem would be protons ionizing the target atoms and being thrown off past the target as hydrogen atoms. Great, since we still just get hydrogen atoms at the beam collector, but kind of useless.

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2. Making a beam of protons to do that would take a pretty decent particle accelerator, I imagine. This too would take a lot of energy.

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Back of the envelope calculation involving overcoming what's called the "Coulomb barrier" (the protons collectively impose a potential which repels inbound positive charges, whether or not the nucleus is radioactive) of a nucleus in the middle of the Periodic Table, reveals that the inbound energy needs to be in the realm of 10 MeV (mega-electronvolts), which is in the realm of the proton accelerator out at TRIUMF, which goes to 500 MeV. But yeah, that's not a backyard undertaking. `

[ 15 February 2004: Message edited by: DrConway ]

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Originally posted by DrConway:

Electrons are negatively charged. Protons are positively charged. There would not be repulsion, but attraction.

[ 14 February 2004: Message edited by: DrConway ]

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The only problem with biodiesel, from a production standpoint, is the alcohol. For the same reason that ETHANOL-GAS mixtures are NOT a good idea, namely EHTANOL production is extremely energy intensive-->requires fractional distillation to achieve the purity necessary. However if Biodiesel is based on fermented Biomass (methanol), the energy requirements would be somewhat minimised, however this would not be acceptable to the corporate farm lobby which plans on making a tidy profit of ethanol for fuel production. That or we go back to the old Direct vertical stroke engines found for example on old tractors and use straight 'filtered' cooking oil!

IF we could put a meter on the sun, you'd see a Solar panel on every centimetre of spare roof space.

[ 16 February 2004: Message edited by: HalfAnHourLater ]

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Originally posted by Willowdale Wizard:
no my friends, the perfect fuel is helium-3.

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Originally posted by Mike Keenan:

As for electric cars, if you mean battery electric cars, there are other problems to consider.

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Personally, I'm gung ho about the potential of flywheel cars.
Then there's that guy in France with the compressed air jobbies if they ever get off the prototype stage. These are effectively electric cars in that you use electricity to compress the air, so the tube full of compressed air is in effect a storage battery.

[ 16 February 2004: Message edited by: Rufus Polson ]

[ 16 February 2004: Message edited by: Mike Keenan ]