Posted on 11/17/2007 12:44:57 AM PST by neverdem
If the hoped-for hydrogen economy is ever to become a reality, researchers must devise efficient ways to produce and store the gas. That will require a series of breakthroughs that have been slow in coming. But researchers in the United States have hit upon a material for storing hydrogen that could be far better than the competition--just the sort of break hydrogen researchers are looking for.
Hydrogen has long been seen as a potentially green alternative to gasoline, which is produced from fossil fuels and gives off the greenhouse gas carbon dioxide when burned. When piped through a fuel cell, hydrogen molecules (H2) combine with oxygen, producing only electricity and water. At room temperature, however, hydrogen is a gas, which makes it difficult to store enough of it on board a car to drive long distances. The gas can be compressed in high-pressure tanks or cooled to a liquid at ultracold temperatures. But both of those strategies require large amounts of energy themselves.
As an alternative, researchers have been searching for materials that can hold large amounts of H2 and release it on demand. But so far the best performers, which are known as metal hydrides, hold only about 2% of their weight in hydrogen at room temperature, well below what is needed for a practical gas tank. Other materials can get up to 7% but require either high or low temperatures, and thus added energy and cost.
Last year, however, researchers led by Taner Yildirim at the National Institute of Standards and Technology in Gaithersburg, Maryland, calculated that a material made from certain metals, such as titanium, and a small hydrocarbon called ethylene should form a stable complex that could bind up to 14% of its weight in hydrogen. Adam Phillips, a physicist and postdoc in the lab of Bellave Shivaram at the University of Virginia, Charlottesville, decided to give the proposal a try.
Phillips used a laser to vaporize titanium in a gas of ethylene. The combined material settled out of the gas and on to a substrate to form a film. When Phillips added hydrogen at room temperature and weighed the result, he found the 14% added weight, just as predicted. After running a series of successful control studies, Phillips and Shivaram reported their new material on Monday at the International Symposium on Materials Issues in a Hydrogen Economy in Richmond, Virginia.
The new result is "extremely interesting," says Gholam-Abbas Nazri, a hydrogen storage expert at the General Motors Research and Development Center in Warren, Michigan. However, Nazri adds, "we have to be very cautious." There have been numerous false starts in the field before, he says. And researchers still must make the material in bulk, demonstrate that it works in that form, and show that it will release hydrogen as easily as it sops it up.
Even with those caveats, George Crabtree, a physicist at Argonne National Laboratory in Illinois, says the result "is one of the most promising developments of the last few years."
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Only true at elevated temperatures. At room temperature, the rate is so slow as to be negligible. Highr pressure hydrogen cylinders are steel (not sure which alloy, but definitely not stainless, because they rust where their paint is chipped/abraded).
It depends. If you do large-scale solar in the desert Southwest, and need to get the energy to New York, transmission of hydrogen by pipeline is more efficient than trying to transmit the electricity directly.
Well stated.
Indeed, the real issue is that hydrogen ions are very small, so small that they easily slip into the metal lattice structure of mast materials designed for strength, used in bulk, in the design of the machines used to propel the vehicles they drive. When embedded in those structures, they act as inclusions which change the materials physical properties, including becoming dislocation generators, causing embrittlement and crack formation.
The high pressures and temperatures merely exasperate the problem, which also exists at lower temperatures and pressures.
I also haven’t seen what other emission problems might result from slight percentages of hydrogen ion and hydroxl ions being released by incomplete or secondary reactions.
Actually virtually all of the hydrogen manufactured in the United States comes from the thermal cracking of crude oil. I worked in the industry for 25 years. Natural gas is far too valuable to waste in manufacturing hydrogen. The methane used in hydrogen manufacturing comes from thermal cracking, they do not bring methane into the refineries from outside.
Then I guess they're right! We're Doomed!
I think that you should reconsider your last sentence after giving due thought to the actual meaning of words.
As I said before ALL hydrocarbon burning vehicles produce water as a combustion product. The white exhaust you see is WATER (steam). Carbon dioxide is invisible in gaseous form.
It’s the smallest POSSIBLE molecule, isn’t it?
Water vapor will make rain in places where it wouldn’t otherwise rain, therefore it is unacceptable.
Producing hydrogen from methane is a bad idea - it's too inefficient. However, producing hydrogen from water by electrolysis or the action of microorganisms seems to be a viable process.
“As I said before ALL hydrocarbon burning vehicles produce water as a combustion product. The white exhaust you see is WATER (steam). Carbon dioxide is invisible in gaseous form.”
Jesus Christ dude, stop using trace elements as an arguement. “Well people exhale water,” no duh. A Hydrogen car would put out a buttload more water then a car.
Black ice.
Actually, the helium molecule is smaller since it is composed of only a single atom. That is why helium diffuses through materials even faster than molecular hydrogen.
One of the most powerful vehicles ever produced, the Saturn V moon rocket, was hydrogen fueled.
My vote is for dilithium crystals held in a warp plasma field...
I've been trying to figure out a way to explain this to the people who think H2 is a "silver bullet fuel".
I like to think of it in terms of money representing energy units. I may not have the numbers right, but the concept is what matters...
Let's say that crude comes out of the ground at $100. Refining and transportation takes $50 and you are left with $50. That's $50+ because crude comes out of the ground with positive value and all that we do is spend some of that value to make a useful form of fuel and end up with a smaller positive value.
Now let's say that we have to SPEND $100 to make H2 that only has an energy value of $25. Our "fuel" now has a value of $75-, or a negative value. This is because I had to pay more for making it than it ends up being worth.
If I'm investing money, H2 is a loser. But since in this example money represents energy units, H2 takes more energy to make than we get back. Petroleum for all it's negatives is a very good energy source. Efficiency in production and use should always be sought when it makes economical sense. But compared to the H2 energy balance, there is no comparison.
If we can come up with a way to make H2 that does not use fossil fuels to produce it (nuclear power), or an efficient and economical alternative method like direct solar conversion, bacterial conversion, etc, it could become more useful as an energy storage medium, but it isn't really a fuel since it must be manufactured.
“One of the most powerful vehicles ever produced, the Saturn V moon rocket, was hydrogen fueled.”
So what. Thee most powerful explosions was hydrogen too.
After launch, nobody drove under the launchpad while going to work either.
OIL products like gasoline and diesel also have the highest BTU per weight, per volume, then all other alternatives. It also doesn’t need to be storred under extreme pressure, or cryogenically. And the engines which use OIL don’t need precious metals like platinum or titanium. Geez.
But doesn’t He have a molecular weight of 2 while H has 1? Is it just more dense?
I think a hallmark of liberalism is wanting change for its own sake. What we have (whatever it is... fuel, enemies) isn’t good enough. We should have OTHER fuel, enemies.
I think they need to keep working on it. I’m fascinated with the idea of using H+ as energy. Just have to find a way to make an energy profit.
YEah but. It’s still very flammable. Just best among the alternatives right now.
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