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New Way to Make Hydrogen
zymano writes "Hydrogen is expensive to make and difficult to store. The most common way in making hydrogen is electrolyzing pure water. A new startup is trying a new way to make hydrogen. The process uses sodium which industry shuns because it generates sparks and heat when mixed with water. Signa has devised a way to mix sodium with silica gel or crystalline silicon to create a powder that essentially strips electrons from the sodium molecules in advance and stores them. When water is introduced, the chemical reaction proceeds calmly. The powder generates hydrogen efficiently. More than 9 percent of a kilogram of the powder gets converted to hydrogen and little energy is lost through heat."
This process may be efficient, but sodium doesnt grow on trees (or mined out of the ground). The easiest way to get it is.... electrolysis of sodium chloride.
So you've just shifted the electrolysis problem further upstream and instead of using nice friendly water, you're passing current through nasty, mean molten salt.
mush of reacted silica gel, sodium, and water??
..you'd have about 10-11 kilos of mush left afterwards.
Say you need one kilo of hydrogen... (Which is about 6 cubic inches in liquifidy form, which is roughly equal to 7.5 gallons of gasolene for the energy you get out of it.. and I go thru around 15 gallons of gass in a week due to my job)
What do you do to recycle or reuse this stuff? How much energy do you have to put into (transporting it, creating/obtaining it, mixing it, etc) it before you can get any out, and how much energy is needed to deal with the waste afterwards?
Because at my current usage a person would have to produce 88 kilos of left overs... per month. Just for me to keep my job with a hydrogen powered car instead of a gasolene powered one I already own.
seems very innefficient for such a efficient proccess.
The idea is not producing hydrogen with sodium as an energy source. There is no pure sodium whatsoever around, it's too reactive (same reason there is no hydrogen in the atmosphere).
So, instead of buying methanol cartridges, we would buy sodium sticks, put some water in a small tank in our laptop, and this would produce hydrogen and power for the machine.
Furthermore, the most common way of producing hydrogen is not electrolysis, but reforming of hydrocarbons (oil and natural gas), which is done on an industrial scale in any refinery.
The article itself has a good number of inaccuracies. For instance, other than the electrolysis thing, you read:
This is insane. The powder does not get converted to hydrogen, the water does. And still I'm afraid a unit error may be lurking.
The PEM fuel cells are not a way to store hydrogen, but a way to convert it to electricity; the solid oxide fuel cells will never be used in vehicles, since they are expensive, running at temperatures up to 1000 degrees, good only for large-scale plants, and brittle. And they take 8 hours to start up, and they can start up only so many times before they start cracking (about ten).
Oh my, did they know that hydrogen is extremely reactive, and will burn with oxygen at the first occasion? You don't even need a spark, all it takes is the static electricity of a windy day. CO2 accumulates, hydrogen would disappear rapidly.
Of course it is. It contains energy. There is no such thing as an energy carrier that does not contain some sort of danger. It would not be much of an energy carrier if it were inert. So, gasoline burns, hydrogen burns, nuclear goes bad big time, methanol burns, and lithium batteries explode if you hammer them or if they are produced with poor standards.
Solid oxide fuel cells do not require a catalyst. They are the only ones that do not, since they operate at high temperatures. Assuming the article meant SOFC.
Common misconception, hydrogen costs about 0.8 euro per gasoline liter equivalent: in Europe that's already way convenient. It's the infrastructure that's missing.
Alkaline metals being ignored? Of all the bullshit... they might not be C, O or even Al, but most know sodium better than technetium, praseodimiun or some transition metal forgotten somewhere in the limbo of rare earths.
Victims of 9/11: <3000. Traffic in the US: >30,000/y
Well, you combine it with oxygen to form water, and then ship it through a pipeline.... oh, nevermind...
That's right. All your base.
A use for all those "WARNING DO NOT EAT ME" packets.
There is truth in humor.
if i only had some mod points... you have, good sir, embiggened us all with your cromulent analysis.
Why do we need to make hydrogen? There's TONS of it sitting right out in the open, ripe for the taking!
My fellow slashdotters, what we need only to do is MINE THE SUN!
All we need is a space shuttle, and a team of roughneck oil workers. With a bit of training they will be SPACE MINERS, and we can send them on their merry way into the sun to mine it for us!
They are also using solar power to create the hydrogen - they have an experimental plant in the Mojave desert, here in California.
The cool thing is that this is a functional, buildable product created by a major car manufacturer. As soon as the hydrogent fuel supply infrastructure exists, they could start cranking these out more or less immediately. If a driver gets stuck in an area where no H2 fueling stations exist, it runs just fine on old-fashioned gasoline. For more information, see their website.
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The story states:
"The most common way in making hydrogen is electrolyzing pure water."
From what I understand, this is wrong. I've heard that most hydrogen is ironically produced as a byproduct of refining oil.
Wikipedia for instance http://en.wikipedia.org/wiki/Hydrogen says that:
"Commercial bulk hydrogen is usually produced by the steam reforming of natural gas."
Coming from a country where a sizeable percentage of energy is generated by wind mills..
- We don't put them right next to places where migrating birds are known to stop. There are no problems with dead birds - they avoid the mills, but it wouldn't do to upset them.
- LF and interference; They are noisy yes, but the LF/interference thing is tinfoil-hat stuff.
- They are ugly; yup. So are smokestacks.
Anyway. Trials are underway to stuff carbon back into the drilling holes instead of releasing it into the air. That shuld keep oil and natural gas CO2 emmission close to zero for power plants.
...and then keep building monstrosities of excess like the Hummer 2...
Your mostly right, except it's called the H2H for the hydrogen version of the Hummer. (See www.hummer.com and click "Hydrogen Hummer" for a video of the governator of Kalifornia endorsing it.)
its not something that does damage as in sets us back. people really overblow this problem. It means growth will slow down. And guess what, those rising oil prices are the greatest incentive towards making cars more "green".
Think about all the people who choose to buy fuel efficient cars. Every person I know who buys them does so because it saves them a great deal of money on gas. Oil prices get up to 70 or 80 dollars a barrel(which isn't hard to imagine with production not increasing by much and China beginning to consume oil on the level of the US) and you will see very few people who are willing to spend 100 dollars to drive a hummer 100 miles. It just gets too damn expensive.
Money works both ways. Making it drives what companies will produce and saving it drives what consumers demand(in large part). So I say if you really want to protect the environment from car emissions, find some way to double the price of oil rather quickly.
1) The most common source of hydrogen is hydrocarbon reforming, done at oil refineries. It's the only economically viable method for bulk quantities. Thus, hydrogen energy is currently dependent on fossil fuels.
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2) You cannot electrolyze pure water -it's a poor conductor. You need some salt, or other electrolyte. Even then, the amount of electrical energy that goes in is less than the energy value of the hydrogen that comes out. And guess where most of the electricity comes from . .
3) Sodium metal causes a fire when dropped into water because of the hydrogen it releases. The activation energy for the reaction between oxygen and hydrogen is very low, and the heat released from the sodium metal - being converted into sodium hydroxide (aka lye, or Drano)- is more than sufficient to cause the reaction (fire).
4) Sodium metal is made by electrolyzing molten sodium chloride (table salt). A very expensive, energy consuming reaction, not to mention nasty (it releases chlorine gas, also).
5) The amount of energy released when an electron is stripped from a sodium atom is the same, whether it's in water or in silica.The energy is either converted to heat or to some other form of energy. Ever hear of conservation of energy (or mass/energy for nuclear reactions)? Unless they've developed something that can do what the transporters and replicators on Star Trek do, the enrgy is still going somehwere. Entropy demands it, otherwise we'd have perpetual motion machines, and ebergy would not be an issue.
6) Mediating the reactivity of alkalai metals is nothing new - that's what amalgams do.
This story does not deserve the attention it has already received.
MM