Naked Science Forum
General Science => General Science => Topic started by: adamgalas on 25/09/2006 18:50:41
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Today in my University Chem course we discussed redox reactions and activity series. I couldn't help but notice that if one runs steam over Iron the result is Iron 3 oxide and H2 gas.
Since the biggest problem with fuel cell cars is how to get H2 without the use of non renewable natural gas or energy inefficient electrolysis, how about the following solution.
1. Use near surface geo-thermal sites, or drill down 2-3 kilometers. At that depth, there are very hot rocks.
2. Pipe water down that turns to steam and is piped back up.
3. Run steam over Iron blocks.
4. Use some steam powered piston to compress H2 gas into tank for storage.
5. Remove Iron blocks periodicly and mix them with Carbon to return turn the Fe2O3 into usable Fe again. The CO2 that is produced can be pumped,(via another steam piston) into a storage tank.
6. Pump the Co2 from the Storage tank into a closed system algea pond so that the algea can generate massive amounts of biodiesel.
I don't have the specifics of the steam pumps worked out yet, but does this basic idea seem to work.
It seems to offer lots of H2 gas for the hydrogen economy while utilizing free geo-thermal power. And of course the algea will provide biodiesel which can suplement H2 in case enough is not produced.
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If we had the technology to do all of this, probably it would be more simple to use the steam to drive geothermical power plants, and then use the electricity produced, in a more convenient way, even to produce hydrogen. But this is only my opinion. However, your idea is not bad.
By the way, welcome in this forum, adamgalas!
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Thank you for the warm greeting Lightarrow, but I must explain why your idea would not work.
Electrolysis for generating H2 is only 10% efficient if I recall correctly. This is why so many in the alternative energy community are mad as hell at all proponents of fuel cells.
They correctly point out that the current # 1 method for achieving H2 is natural gas, and the process for extraction releases CO2, thus not solving global warming, nor our reliance on fossil fuels.
Electrolysis, though woefully inefficient is feasible, Honda Motor Co currently does this in one of their California Hydrogen stations useing Solar power. However that station takes all week just to generate enough H2 for 1 car.
Electrolysis for tens of millions of cars would consume hundred's of powerplants worth of electricity, and currently those powerplants run mostly on Coal, the dirtiest fossil fuel available.
In order to use electrolysis in an eco/sustainable friendly manner one would need alternative fuels, such as solar, wind, hyrdo, wave, geo-thermal ect. But there is simply not enough of such power available.
Realistically we would need to conserve massivly, build forests of wind turbines, fill desserts with solar panels and have wave power collectors on every beach just to meet today's needs. Throw in the extra power demand for Electrolysed H2 and you can see the problem.
Proponents of the H2 eonomy then stike back with, "nuclear power is plentifull and clean, at least no CO2". But this will also not work.
It would take decades to build all the nuke plants needed and how soon would it be until we ran out of U-238? As time went on it would take more and more mining to get just one ton of low grade ore, and that would need to be enriched, thus consuming even more power.
Thus the need for a means of generating H2 that doesn't use massive quantities of electricity, nor needs fossil fuels.
Currently there are two methods of this that I know of.
1. Certain bacteria and algea can be made to generate H2 when certain nutrients are denied to them. Researchers are currently working on massivly increasing yields so that a commercial operation of this manner could succeed.
2. More currently feasible is biomass, having trash collect and be decomposed by bacteria. The bacteria give off methan, which is CH4, from which 2 moles of H2 can be generated for each 1 mole of the gas. The CO2 generated in this process can be sequestered, or better yet, pumped into the closed system algea bio-sheres I mentioned previously.
In case you haven't heard, certain species of algea, those extremly high in lipid concentrations, can be made into biodiesel. In a secure closed system, given enough sunlight and CO2, these wonderfull creatures can be made to yield 20,000 gallons of biodiesel/acre/year.
In case you are unaware, Biodiesel is a completely non toxic fuel that contains more energy/gallon than gasoline, and so gets better mileage. It is one of the best hopes for a sustainable and prosperous future.
3. The method I just described. It would only require that one be close to some body of water, preferably fresh as not to fill the shaft with salt.
Having thought a little bit more about it I can now imagine an additional benefit. Since liquid H20 expands by 1000 times when turned to steam, flooding a deep enough shaft, (if the rocks are 200-300 degrees Celsius) the amount of steam generated with litterally be explosive. This steam will not need to be pumped to the surface but will explode out like the oil gushers of the old energy era.
If one had the pipe opening into a iron matrix like structure, of which their were several, each slightly offset from the others, then the all of the escaping steam would come in contact with the Iron and all of the oxygen would be stripped away, deposited on the iron in the form of rust, while the lighter and now free H2 would rise upwards were it could be collected and pumped, via steam pump, into a high pressure holding tank.
In order to maximize output the iron matricies would be attached to rotating arms that were constantly in motion. As one side of the iron rotated in front of the steam pipe, the opposite sides,(it would actually be a circle) would rotate out of the steam and into the back of the device.
Here there would be high pressure air sprayer,(pressure maintained by a steam piston) that sanded the iron matricies with graphite. This would cleanse the iron of its rust and leave it ready for more steam by the time it rotated back into position in front of the steam pipe.
The excesse graphite would fall to the bottom of a collection tray that would use a heppa filters, (on a moving conveyer so as not to et clogged) to collect carbon but allow the heavier than air CO2 to drift down into a colletion chamber where another steam piston would be waiting to pump it into tanks from which it would be sent to nearby algea farms to generate biodiesel.
This system would be powered completely by geo-thermal heat, and would be locatable anywhere there is a fresh water source, preferablly self replenashing, such as a river. Any power required that would be inefficient to be generated steam could come from the biodiesel generated in the nearby algea farm, or wind and or solar
The entire opperation, both steam H2 and Algea biodiesel would be 100% renewable, non-polluting,(biodiesel generated in the manner described would be 100% carbon neutral) and self reliant in terms of its own energy needs.
Now if only I had won the powerball lottery I would have the $60 million needed to build such a plant:)
Hope that helps explain some of the current issues with the hydrogen economy.
Before I go I should mention that with the latest in plug in hybrid technology and advances in batteries, it is now regarded by many in the alternative energy community that Full blown eletric cars will eventually come to dominate the future automotive needs of the world.
The reason is that current hybrids have opened people's eyes to the benefits of green tech. People no longer fear buying a hyrbid because the reliability of the Prius and its bretheran have proved the tehnology ready for prime time.
Now Toyota and Nissan are saying that by 2010 they will introduce hyrbids with larger more powerfull batteries that can take a vehicle 25-50 miles on pure electricity. This means that MPG of gas will rise to 100 + (electricity to charge them will come from evening low peak hours, which are much cheaper than gas).
By 2015 as batteries become 2-3 times more energy dense than today the range on a PHEV will increase to 75-100 miles.
By 2020 batteries will improve even more and better methods of manufaturing Carbon fiber will allow vehicles to weight 35-40% less, thus extending range to 200-300 miles.
By 2025 range will achieve 400-500 miles and the gas engine will be eliminated completely. Thus will come the Eletric car.
The benefits of which inchlude the best possible energy efficiency, (electric motors have almost no moving parts and the fewer steps needed to turn the wheels, the better the efficiency.)
Thus many argue that by the time fuel cells become economical, EVs, which can be powered by completly fungible, renewable power, will make them obsolete at inception.
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The problem that you don't seem to have taken into account is that making iron consumes large amounts of energy. A tonne of iron consumes several tonnes of coal to produce, so unless you know of a plentiful source of native iron I don't think this would work. Especially as it is far more efficient to recycle iron to make more iron than to make it anew..
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quote:
Originally posted by adamgalas
5. Remove Iron blocks periodicly and mix them with Carbon to return turn the Fe2O3 into usable Fe again.
Better keep in mind that this little detail requires a blast furnace in order to have an acceptable yield !
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I didn't say it because I imagined he to use the same inner ground heat for that purpose.
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In terms of iron supply I will purchse used iron for my geo-thermal hyrdo-pipe. I apologize for describing the iron utulization so poorly. It would look like giant tennis rackets with iron strings, staggered and attached to a giant roating drum.
The graphite sanding would quickly remove all rust from the iron as the drum rotated, placing the rejeuvinated iron back in front of the pipe.
I realize that many questions still remain about such an opperation, such as how exactly would the steam piston pumps work, how many pipes would it take just to run the equipment, ect.
Unfortunately the idea is just a prototype in my head.
I am currently busy with my studies, (pre-med with a major in Economics) and so don't have the luxury to draw up blue prints.
But If I ever fall into a massive pile of money, such as winning the lottery, or having my small cap stocks explode, then perhaps I will fulfull a life long dream of building an empire consisting of companies that generate clean, renewable energy.
Heck, even if the hydrogen economy dies in its cradle, I could still build a geo-thermal power plant anywhere near a river. Those super EVs have to get power from somewhere, so why not from Geo-Green Power?
Of course if anyone is interested in investing in such a start up I will devote all my energies into such an endevour. I am currently studying at the University of Minnesota and we have some very good engineers who could help with the fine details of such a project. In addition I could find some top-key business managers at the Carlson School of business. Of course, I am wasting time babbling on like this as it is highly unlikely that we hear at the naked scientist forums could raise the millions needed just to build a proof of concept power plant.
Oh, well one can dream.
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I am unconvinced that the hydrogen economy is the right route. hydrogen is particularly difficult to store effeciently and it is probably better to do an accelerated carbon cycle and manufacture short chain hydrocarbons to make petrol using carbon dioxide water and sunlight using catalysts.
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in the quote on quote "fourth generation nuclear reactors", they will use spheres of uranium coated in various things, this not only prevents a melt down (by what they coat it in, i forget sory, but htis is what the article said) it will also produce electricity and excess heat that could be used to split water to hydrogen...or something
idk but personally i think nuclear and/or wind + solar is the best way to go, and then it will just be an electriciyt economy, not a oil economy