In which the press and the government prove they don't understand scientific basics

[unixronin]

ERIE, Pa. - An Erie cancer researcher has found a way to burn salt water, a novel invention that is being touted by one chemist as the "most remarkable" water science discovery in a century.

John Kanzius happened upon the discovery accidentally when he tried to desalinate seawater with a radio-frequency generator he developed to treat cancer.  He discovered that as long as the salt water was exposed to the radio frequencies, it would burn.

[...]

The radio frequencies act to weaken the bonds between the elements that make up salt water, releasing the hydrogen, Roy said.  Once ignited, the hydrogen will burn as long as it is exposed to the frequencies, he said.

[...]

Roy will meet this week with officials from the Department of Energy and the Department of Defense to try to obtain research funding.

The scientists want to find out whether the energy output from the burning hydrogen — which reached a heat of more than 3,000 degrees Fahrenheit — would be enough to power a car or other heavy machinery.

OK.  Who else sees the beginner-obvious problem with this "discovery"?

Hint:  The Laws of Thermodynamics.

This is, of course, beyond both the AP and the government bureaucracy.

Comments

[robbat2.livejournal.com]

Wouldn't piping the plain salt water be more effective and safer? Depending on their extraction efficiency.

While thermodynamics do apply, having salt water as a way to store the energy and still being able to extract it does use, it's corrosive, but a lot less so than the internals of other forms of energy storage. If they can do it without setting it alight, it might also be very interesting for a hyrodogen fueling station setup. Pipe salt water, convert to hydrogen on the far side as needed.

[novel-tharkun.livejournal.com]

Yes & no. The energy to extract the Hydrogen would at best equal the energy obtained, and the latter would actually be less. Using a solar or other otherwise-wasted energy source isn't as helpful. San Diego was specified for, I assume, having an excess of the mentioned solar power. By transferring prior to extraction, you need that power on hand to obtain the power source.

From my (outdated) readings, storage in metal hydrides was almost equivalent in energy density to cryogenics, and far less equipment was needed. The resultant material for transport was higher density, but it has fewer safety concerns, which leave the engineering scales somewhat in balance.

[unixronin.livejournal.com]

From my (outdated) readings, storage in metal hydrides was almost equivalent in energy density to cryogenics, and far less equipment was needed. The resultant material for transport was higher density, but it has fewer safety concerns, which leave the engineering scales somewhat in balance.

Metal hydride storage showed great promise for energy density, yes. However, my recollection is there are technical hurdles which have not yet been solved that make it impractical, one of which — if I recall correctly — is the necessity to heat the hydride to about 400°F to initiate hydrogen release, which means "engine" startups require a lot of stored electrical power. What's worse, the heat to "start" the hydride system cannot be recovered when you shut the system off, so it is lost, making short runs extremely inefficient. Another problem is the mass and cost of the hydride matrix itself.

Currently, the technology of fuel cells "burning" hydrogen produced from liquid hydrocarbon fuel by a reformer is looking a lot more technically feasible. Much of the current research is going into methanol reformers (http://en.wikipedia.org/wiki/Methanol_reformer), but methanol reformers have the drawback that even though the reformer/fuel-cell combination is much more efficient than burning the hydrocarbons in an internal combustion engine, the reformer still produces CO₂ as a by-product.

It'd be nice to see really practical fuel-cell cars, but it's too early yet to tell whether it's actually going to happen. The Tesla roadster (http://www.teslamotors.com/index.php) has proved that an electric vehicle can perform well enough and operate economically enough to be accepted in the market (the Tesla's power cost of 2¢/mile compares very favorably with internal-combustion powered vehicles running on gasoline, diesel, or liquefied petroleum gas), but that's only half the problem. It's also got to be affordable to the mass market, both to own and to maintain; the Tesla costs about $100,000, far beyond what most people can afford to spend on a car. (According to Tesla, this includes the cost of recycling the battery pack when it wears out, but they're rather cagey about how much that cost actually is.)

[unixronin.livejournal.com]

It's really not the water that's the issue. And your water supply doesn't need to be salt water — you can re-use the salt, just add new water as you electrolyze it. (That's all this really is, just a different method of electrolysis using RF energy instead of direct electrical current.) The issue, really, is that you're not gaining any energy — all you're doing is electrolyzing water, leaving you with hydrogen gas that's rather more difficult to store and transport than it would be to just use the electrical energy that you electrolyzed it with for power instead in the first place. Whether you supply it directly as current or as RF, it takes a certain amount of energy to break the hydrogen-oxygen bonds, and you're always going to have to put at least that much energy in to break them, and you're only ever going to get at most that much energy back out by recombining them. The only thing it's really adding is conversion losses.

GM is experimenting with fuel cells and high-pressure hydrogen storage tanks in its Hy-Wire (http://auto.howstuffworks.com/hy-wire.htm) project, which has a stack of 200 fuel cells running off three carbon-composite high-pressure hydrogen tanks buried inside the "skateboard" and producing 124 kilowatts peak power, 94 kilowatts sustained. The Hy-Wire does a good job of illustrating the problem. The Hy-Wire's tanks weigh 165lb, but hold just 4.5lb of hydrogen compressed to 5,000psi (350 bar). GM is hoping to double that to 10,000psi in future versions, to increase range.

GM is being pretty cagey about what the vehicle's current range is, but we can do a back-of-the envelope calculation. The calorific value of hydrogen is 150 kJ/g, three times that of gasoline (http://home.att.net/~cat6a/fuels-VII.htm), so that 4.5lb of hydrogen is the energy equivalent of 13.5lb of gasoline ... which, at 737.22 kg/m³, or about 6.15 pounds per gallon (http://en.wikipedia.org/wiki/Gasoline), is just barely less than 2.2 gallons. A vehicle the size of a minivan doesn't go far on 2.2 gallons of gas. On most vehicles, that's about when the "low fuel" light comes on. Granted, fuel cells are more efficient than IC, but I'd still be surprised if the Hy-Wire's range to empty is much over a hundred miles, and very surprised if it's over 120.

(Compressing that 4.5 pounds of hydrogen to 5,000psi in the first place takes a fair bit of energy, too. Calculation of the actual amount of energy required is left as an exercise for the reader.)