Half a croissant, on a plate, with a sign in front of it saying '50c'
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Free Atmosphere Fuel Cell

Power for the future
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(+3, -1)
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Fuel cells work by passing hydrogen across one electrode and Oxygen (or just air) over the other. (Hydrogen ions then go through some gooey stuff in the middle, electrons widdle around any electric circuit you care to mention, they all meet up and you get water while powering the electric circuuit of your choice.)

If you fitted a membrane over the hydrogen electrode that only allowed hydrogen to pass you could expose both electrode to the air and get some free juice.

The worlds energy problems solved!


1) Can we make the membrane? (trivial I would have thought - hydrogen atoms are skinny which should help)

2) Is there enough spontaneous splitting apart of water in the atmosphere to produce enough free hydrogen impacting on this membrane or is there any common process or situation that leaves a bit of hydrogen 'kicking about'?

st3f, Apr 18 2001

Maxwell's Demon Tamed http://www.sciam.co...ue/0299scicit1.html
Random molecular motions can be put to good use [st3f, Apr 18 2001, last modified Oct 21 2004]

DOE H2 Conference http://www.eren.doe.../docs/28890toc.html
Proceedings of the 2000 Hydrogen Program Review [Dog Ed, Apr 18 2001, last modified Oct 21 2004]


       yeah, im not sure the membrane can be produced, but then im not too good with stuff at the molecular level. then again, it's probably possible given the advances of today's nanotechnologies, so im for any cool way to get electricity.
tkeyser, Apr 18 2001

       Water has a certain amount of dissociated hydrogen naturally (the pH of neutral water is 7, which means that there's a hydrogen ion concentration of 10^-7 moles/liter).   

       So basically what you're trying to do is use reverse-osmosis to extract hydrogen, and then burn that hydrogen for energy. The problem is that reverse osmosis only works when there's a large pressure differential --- you need to force the hydrogen through the membrane. In order to get hydrogen for your fuel cell, you're either going to have to pressurize the air going through the membrane (which would take energy), OR have the interior of the cell at low pressure, which means you'd have to pump the exhaust gases up to atmospheric pressure in order to get rid of them, which would take energy.   

       I have a hunch that the amount of energy required to do the pumping would exactly balance the energy you could theoretically extract from burning the hydrogen ... physics is funny like that sometimes.
wiml, Apr 18 2001

       Peter, I don't think this is really a free-energy scheme, it's more like resource extraction. The membrane bit is probably very feasible--selectively-permeable 'branes are used at the industrial level in dissolved-oxygen sensors, chlorinated water sensors, oxidation-reduction potential sensors, etc.   

       I agree with wiml, atmospheric H2 is really sparse. (This is a Good Thing. I would hate living in an explosive atmosphere. Briefly.) And I suspect any industry which generates H2 as a byproduct is already using the gas--landfills and sewage treatment plants produce methane and many of them use it to produce electricity.   

       Can you somehow use hydrogen sulfide instead, perhaps by using some sort of catalyst to split the gas into free H2 and nice marketable sulfur? Or make a fuel cell that uses methane more efficiently than conventional cogeneration technology (big diesel-type methane-burning piston engines)?   

       This is neat, and I like the idea.
Dog Ed, Apr 18 2001

       I would just like to speicify that, as a native Californian, and as such very interested in renewable energy resources (tranferring virtually inexhaustible abundant natural resources, such as sun, wind, air molecules, into usable electricty/energy), I would never in my life deign to use the term "widdle."
globaltourniquet, Apr 18 2001

       From the original posting my feeling is that:   

       1) A membrane must be possible but as wiml states there must either be lots of free hydogen about or gas under pressure for it to work   

       2) is more difficult.   

       Although Hydrogen is the most common element it is quite reactive and therfore quite sparse in its unattached form. What we need for this to work is one of the following. (please add if you find more)   

       a) Local concentrations of hydrogen. Dog Ed says that any industry producing hydrogen gas as a by product would use it for something already. I agree. They'd be daft not to. What about small scale processes where it is not economic to capture hydrogen? Are there any? Would they produce enough H2 for a membrane to be useful?   

       b) Pressure to force sparse amounts of hydrogen across a membrane. I don't like the idea of generating the pressure myself. Sounds self defeating. Again we would need to find situations where a pressure difference would occur natuarlly. I can't think of any gaseous ones but how about using water as a hyrdogen source. Mains water is already pressurised and if you sink the fuel cell membrane device into sea water you would get pressure from the depth. Question is would either of these get H2 across a membrane.   

       c) Use Hydrogen Sulphide [Dog Ed]. My main aim with this posting was to try and use things that are freely available or are waste products of another process. Is Hydrogen Sulphide produced as waste by any industry?
st3f, Apr 19 2001

       st3f: I think Peter's cutting remark about high-school chemistry (I didn't have chemistry, just hormones) was meant to remind me that you'll put more energy into producing H2 from H2S than you'll get out. H2S is flammable, but I don't know that it is used as a fuel. It is a despised pollutant; I'll try to find out what industries produce it in quantity. Here are its vital stats:   

       chemical compound, H2S, a colorless, extremely poisonous gas that has a very disagreeable odor, much like that of rotten eggs. It is slightly soluble in water and is soluble in carbon disulfide. Dissolved in water, it forms a very weak dibasic acid that is sometimes called hydrosulfuric acid. Hydrogen sulfide is flammable; in an excess of air it burns to form sulfur dioxide and water, but if not enough oxygen is present, it forms elemental sulfur and water. Hydrogen sulfide is found naturally in volcanic gases and in some mineral waters. It is often formed during decay of animal matter. It is a part of many unrefined carbonaceous fuels, e.g., natural gas, crude oil, and coal; it is obtained as a byproduct of refining such fuels.   

       <addendum>The above paragraph is a quick grab from on-line encyclopedia</addendum>
Dog Ed, Apr 19 2001

       If I understand Dog Ed what we have is the chemical reaction:   

       2H2S + O2 -> 2H2O + S2   

       [Supply your own subscript]
(not sure whether it should be S2 or 2S but I'll let it ride if you will)

       ...and that the above is a sustainable exothermic reaction.
What we would like to do is create a middle stage:

       2H2S + O2 -> 2H2 + S2 + O2 -> 2H2O + S2   

       The second reaction we can make energy on - hopefully enough to drive the first if it is not energetically favourable.   

       My chemistry is very old and wasn't too sharp in the first place so I'll have to ask the questions: Is this what we are trying to achieve with 2c? Could this work?   

       Please post back on 2a, 2b if you have any ideas too.   

       PS I don't want to start a flame here (pun unintentional) but the only change I recall making to the title is moving it from lower case to title case to make it fit with the other entries. To clarify any confusion the posting is about "free energy" only in the sense that no-one else is using it. I'm not attempting to break *any* laws of thermodynamics. Not today anyway. :o)
st3f, Apr 19 2001

       You can of course produce energy from H2S; it burns, if nothing else.   

       You cannot produce energy from "free atmospheric hydrogen". Your plans to do so are on a par with Maxwell's Demon and will never work. If you could generate hydrogen from air, you wouldn't need any fancy fuel cells -- just burn the stuff! No, no, no, completely impossible.
egnor, Apr 19 2001

       Added link "Maxwell's Demon Tamed".   

       Egnor. I agree with you - the "Free Atmosphere Fuel Cell" is not viable in the form I originally stated it - but not for the reason you state.   

       I don't believe that Maxwell's Demon is a problem here.   

       I do believe that scarcity of hydrogen is.   

       Have a read of the link and see if you can find a set of reasonable circumstances that will allow the system to be viable.
st3f, Apr 19 2001

       Quick comments to everyone:   

       Peter - Sorry, you can't patent anything that's already been put in the public domain. :o) (not that I understand you'd want to anyway)   

       Dog Ed - I've realised very late in the day that the H2S idea breaks down to two reactions:   

       2H2S ->; 2H2 + S2
2H2+ O2 -> 2H2O

       The first costing energy to produce the hydrogen - the second being a straight forward fuel cell reaction. There's no need for the hydrogen permeable membrane and I propose removing the idea from this posting. Do you want to create an item, "Using a fuel cell to generate electricity from Hydrogen Sulphide" or some such. I'll then delete the stuff from this posting and link to you for that.   

       All: I want to do an edit within the week to try to present the idea so that I can make more sense from the feedback. e.g. Peter's last one - I don't know whether he's saying that he doesn't believe a hydrogen permeable membrane will work a) because of Maxwell's Demon b) at all for some other reason c) in the atmosphere but may work somewhere else d) in any locaytion he can think of but there may be one somewhere. comments may disappear but I'll try to keep the balance and structure.
st3f, Apr 20 2001

       st3f: Forget the details. It's all about conservation of energy (which is why I brought up Maxwell's Demon). If there were free chemical energy in the atmosphere waiting for liberation, it would already be liberated. (That's why there's no free atmospheric hydrogen; it's all combined with the oxygen and sitting in the ocean. Well, that and the fact that it tends to escape into space...)
egnor, Apr 20 2001

       Peter - fair comment on the patent. (I'll delete you later) :o)   

       egnor - I see where you're coming from. I hope you'll indulge me in a quick think before I edit this entry down at the weekend ready for long term hibernation.   

       Thought: A thermocouple is a neat idea but is no use without a temperature gradient. Is there a situation we can find in the world where one plate of the fuel cell (with hydorgen passing membrane in place) will encounter significantly more unbound hydrogen than the other plate which is exposed to air.
st3f, Apr 20 2001

       st3f: Your rusty chemistry is better than mine anyway. I suggest that if you want to run with any kind of H2S utilization it should be under your rubric.   

       I might also tentatively mention that the original idea was original, but we may be moving from halfbaked toward refinements of existing technology.
Dog Ed, Apr 20 2001

       [*****Have a read of the link and see if you can find a set of reasonable circumstances that will allow the system to be viable.*****]   

       st3f: Several papers bearing on your idea were presented at last year's Hydrogen Program Review Conference (US DOE)   

       Membranes: Unqualified go. Current technology uses palladium alloys or organic polymer membranes. Better membranes (ca 20 microns thick) are being developed using zeolite-type molecular sieves.   

       Hydrogen from H2S waste streams: Under development. Current technology (the Claus Process, whatever that is) recovers only the elemental sulfur and wastes the hydrogen (as water). The developing technology uses superadiabatic combustion to recover H2 and elemental sulfur along with water; apparently the key is to combust the H2S at very high temperature in a porous ceramic medium. According to the authors, this offers "...the potential for hydrogen production at very low or even negative cost..."   

       Hydrogen from water: Under development. "We have been investigating the use of organic pigments as semiconductor photocatalysts in a dual stage water decomposition scheme that would ultimately use solar energy to generate hydrogen from water."   

       So there you have it, st3f. You may not get H2 from the atmosphere, but everything else we've talked about is being seriously explored. I'll post the link to the DOE conference page; the papers I referenced are "Defect-Free Thin Film Membranes For H2 Seperation and Isolation," "Hydrogen Production by Superadiabatic Combustion of Hydrogen Sulfide," and "Solar Photocatalytic Hydrogen Production From Water Using A Dual Bed Photosystem."
Dog Ed, Apr 24 2001

       Note that this is *not* free energy. Photocatalysts, for example, require sunlight to split water.
egnor, Apr 24 2001

       egnor: No, of course it's not free energy. The authors of the paper on the process call it "...the highly efficient storage of solar energy in the form of H2 via photocatalytic decomposition of water." Also, see comment of Apr. 18: [I don't think this is really a free-energy scheme, it's more like resource extraction.]   

       What's interesting to me is the way st3f's idea morphed under Halfbaked discussion into a form using technology that is indeed being actively explored. The Halfbakery does, oddly enough, connect to the real world.   

       Pats on the back all around, I think.
Dog Ed, Apr 24 2001

       Hi all, The idea of using Hydrogen Sulfide for anything is probably not a very good one. Considering the first scent of rotten eggs destroys the smell sense in your nose leading to breathing more and higher concentrations and within a few seconds DEATH. At least with pure hydrogen it will dissipate quickly and if you breath some it won't extinguish your life instantly. After working in the oil fields for a spell i can assure you that any flammable byproduct from the well is used in either the natural gas we use for cooking or within the oil field equipment itself. Some wells use the natural gas produced by the well itself to power a combustion engine that runs the pumping unit. I guess one question would be what about using the difference in temps to create the pressure differential. Second if that doesn't produce enough of a pressure differential, then what about the use of gases in a liquid stated to produce a larger differential. Third is why bother using a membrane to try to produce a small amount of electrical power when hydrogen itself could be used for a combustion engine, converting a gasoline engine to run on natural gas is being done as we speak wouldn't it be feasible to use the same setup to deliver hydrogen to the engine to create power. most people think of the Hindenberg when you mention hydrogen, but we all know that mixing hydrogen with oxygen creates water. If you were to insert a small cylinder of oxygen into the larger cylinder of hydrogen that is released during a serious accident if the hydrogen tank is ruptured, this would take any worry of the hydrogen tank exploding as water doesn't explode. Last ... I know that using hydrochloric acid and adding zinc pellets will produce hydrogen ...is there something that mixed with water in a normal fashion will cause the hydrogen to break from the oxygen atom? Chemistry was 20 years ago and actually I will be taking college chemistry this summer .... may have an answer after that ....   


whampoo, Apr 05 2003

       Sodium, Cesium and a few other highly reactive metals will displace hydrogen from water - and the reaction is QUITE exothermic.   

       Referencing an earlier post, yes Zinc and many other elemental metals will displace hydrogen from any acid, depending on their reactivity. Maybe scrap metal in some kind of organic acid could be used as a weird kind of semi-renewable energy source, but the inefficiencies would be, IMO, pretty severe.
justibone, Mar 12 2005

       <offbeat> good moniker "whampoo" <offbeat>
skinflaps, Mar 12 2005


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