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Discussion in 'Current Events' started by Stelliform, Feb 13, 2004.
Pretty Cool stuff!
I've heard knowledgeable people say that if we had developed hydrogen-fueled engines before hydrocarbon-fueled engines, we wouldn't ever even consider using gasoline, much less diesel fuel.
Of course, I mention the Hindenberg and they roll their eyes....
There are 2 issues with hydrogen power.
1) You need power to make it. You can''t go and dig it up somewhere. Oil coal, natural gas etc have been piling up energy since the dawn of time. When we want hydrogen we have to make it. In this case from ethanol. (On a side note: where does the carbon from the ethanol go?)
2) Energy density wise it is hard to be gasoline on a per m^3 basis and its good on a per kg basis. It is hyper-($%#$ can't remember word) You get energy for breaking it down. Hydrogen is a pain to work with. It is hard to compress to any reasonable density, it tends to leak through solid metal and in the process makes it brittle.
True -- I've heard that there are significant hurdles in making H2 work well. (I think the idea behind solving the storage problem is to have a mechanism that releases it from methane/ethanol/whatever on an as-needed basis.)
Regardless, the whole draw of this is the no/low-pollution aspect. But your question of what becomes of the waste products is a good one.
Some of my friends way back in high school made their own Hydrogen fuel car by modifying an existing old junker. They used standard gas cylinders filled with Hydrogen and Oxygen. Refilling the cylinders was a bit of a pain and the car would likely be dangerous in a severe accident. It tended to leak a lot of water.
Likely it is falls out of solution as sediment and collects at the bottom of the ethanol holding tank while the hydrogen raises to the top. If the carbon were collected in anyway that made is gaseous (such as by carbon dioxide) it could interfere with the burning of the hydrogen and efficiency of the reaction.
I think you might be looking for hyperthermic. But the reaction has to be hyperthermic either way or you wouldn't get any energy from hydrogen either . But I understand what you mean by Hydrogen being a pain - didn't know it could leak through metal tho . I imagine that's due to it's size and the relatively large holes (by comparison) that are in most alloys.
That's because hydrogen is actually relatively non-reactive with oxygen under normal circumstances. You need an electric spark or flame to actually get the hydrogen to ignite. If your going to worry about raw elements in an oxygen atmosphere, Sodium, Potassium and the other Alkalis are MUCH more reactive than Hydrogen, mostly because Hydrogen exists naturally in a diatomic state. This makes it much more stable than the metal's below it, and in terms of reactivity, closer to the halides (Fluorine, Chlorine, etc).
Agreed -- in fact, very deep scuba divers actually add a small percent of hydrogen gas to their breathing mix which doesn't spontaneously react with the available oxygen.
I'm not so sure that the concern is with raw elements, per se, but rather that automobiles are a spark-rich environment.
Don't get me wrong -- I forsee hydrogen fuel as the future. The big question is are the risks less or greater. Since the risks are different from fossil fuel engines, comparisons may not be so straight forward.
I thought that was helium in the mix....
Anyways, I saw this title and thought it was a nuclear reactor/fusion
This technology is going to be needed for fuel cells to become a viable working system. Making hydrogen from ethanol has economic impact as well - requiring a lot of distillation from crops. There isn't enough hydrogen freely available yet to supply a huge demand.
Great stuff.....I wonder if you could have a separate system that would convert plant material into hydrogen....all those grass clippings/leaves/weeds could be put to good use Make a nice closed system.
I'll withhold judgment
I can remember when those scientists thought they had Cold Fusion going (even made the cover of Time Magazine) and that came to be a big fat zero...
Yes. Hydrogen leaks through metals thats one way they separate tritium from helium. They filter it through a sheet of palladium
I don't think it is hyperthermic. If you take a look at the enthalpy(I think) of combustion hydrogen is 0, oxygen is 0, carbon is 0, Gasoline is 18,000 (kJ/Kmol) Acetylene is like 30,000. (These numbers are from memories a decade old of thermo2 so take them with a grain of salt.) H20 is -180,000 CO is -150,000 with CO2 being -280,000.
You can actually get energy burning Carbon Monoxide and they actually used to use it. (Gas lights...)
Most of the Hindenburg was the shellacked canvas impregnated with powdered aluminum...
Hydrogen burns almost clear.
Re: I'll withhold judgment
They got it working. Its just not as easy as everyone thought it was. They actually even managed to get enough power out of it that they could in theory slap in a carnot engine and generator to power it. This is an accomplishment given the fact that it was still low temperature.
Honda is actually working on some cold fusion research. There are a few things that need to be done to get anything that is useful though. Once someone does it, everyone will have it.
Re: Re: I'll withhold judgment
If anyone can accomplish this certainly it will be Honda. Detroit needs to focus more on alternatives also. I think that they were first with the Hybrid. If ti turns out that they use ethanol, then the Midwest will be the beneficiary. Finally clean energy.
sure fossil fuels might have a high energy to mass ratio and all that, but stores of energy like that, found somewhere on the earth just sitting there, waiting to be tapped, all have a problem; they're limited. on top of that, obtaining energy from them is usually harmful to the environment, although it seems like not too many people care about that. at least that stuff is gonna become quite scarce in the coming years.
yeah, hydrogen gas isn't readily available on our planet... maybe some day we can hook up a pipe line to jupiter or something like that.... hydrogen is of course by far the most abundant element in the universe.
but until then, whether we obtain hydrogen gas through vegetation or electrolysis of water or something along those lines, it can be a great way to store energy that ultimately comes from the sun into something that's portable (although at this point, the portability is somewhat limited, but i think those issues will be worked out soon enough).
i think the combustion of ethanol instead of pure hydrogen also brings up a lot of issues, but these are to me a bit more serious than the technicalities of storing hydrogen gas. For one thing, there are byproducts which have to be completely recycled somehow if its to be a truly sustainable fuel. Also, producing the ethanol in the first place would need a crazy amount of agricultural land, if you're hoping to power homes and vehicles with this stuff. i know we produce more than enough food on this planet, but supplying a significant chunk of our society's energy would be quite the added burden.
we just need clean ways of generating electricity, then we can use that electricity to store our energy in hydrogen gas that we get out of the ocean. after we burn the gas, the water vapour goes into the atmosphere and eventually rains back down on us. its a great way of taking energy from the sun and turning it into something that can move our cars around.
The only problem with solar power is that even if we could get 100% of the energy from sunlight to electricity, it wouldn't be enough to power everything.
The only real alternative clean source of power is going to be nuclear. Sadly politics stepped in some time ago and left us in the US with 40 year old technology.
I think that even burning ethanol creates greenhouse gases, so if you believe in global warming, greenhouse gases might not be good thing.
I read a study on the Hindenberg disaster, and the Hydrogen wasn't the main cause of the explosion. The biggest problem that they had was the paint on the 'balloon.' Of course they didn't know that it would be a problem back then, but the paint they used was chemically extremely similar with NASA's current rocket fuel technology. If only they'd known huh? It certainly does seem like a poor decision to put flammable gas inside a rocket fuel painted balloon and then use it to transport people.
Personally I blame Jane Fonda.
Who growing up as a kid wanted a fast breeder reactor.
Fast breeders would be nice but won't happen, stupid politicians!
They could at least reprocess the spent fuel we have now, but I don't see that happening any time soon.
Currently, we are changing from a carbon based to a hydrogen based society. We have actually stopped increasing our use of carbon based fuels, and are on the beginning of the decline. Right now, the most promising thing is natural gas. Methane is much cleaner than other fossil fuels. We actually have enough coal to provide energy for the world for another 200 years, but we'd never use it because it's so dirty.
Nuclear power is also very safe too. The US Navy has a flawless record with nuclear power, and the only US nuclear accident was because of poorly trained staff not knowing what they were doing at Three Mile Island. The computer fixed the problem, but the people there did their own thing, and almost had a meltdown on their hands. Proper staff training, and even smarter computer systems can ensure safe and reliable nuclear power...
That along with fast breeders were made illegal by Jimmy Carter due to weapons fears. One would think that making new fuel rods out of spent fuel would be safer than just sticking it someplace.
Just don't let MS write the software! Think about the havoc a worm could do in that system! Encountered a Fatal Error, indeed.
That's not completely true. Popular Science showed a few years back where something like 100 square miles (I don't remember the exact number) of solar cells with todays technology in the undeveloped portions of Arizona could develop enough power for the entire United States which is by far the biggest resource user in the world.