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Turning Salt Water into Fuel

  1. Feb 5, 2009 #1
    Here's the link:

    http://www.popsci.com/scitech/article/2007-11/turning-water-fuel

    I find the idea interesting that the radio waves may assist in breaking the oxygen-hydrogen bonds of the water molecule. But, why should this effect only exist with salt water and not pure water? Salt water is ionic and permits current flow?

    The applicability of such an idea for a potential fuel seems very far off. The radio wave generator requires a large energy input compared to the output from ignited gases.
     
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  3. Feb 5, 2009 #2

    mgb_phys

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    It's not a fuel source, you need to put more energy in to break the O-H bond than you will get back when you make it again by burning.
    At most it's a hydrogen generator - with the slightly inconvenient feature that it generates an explosive H2 O2 mix rather than just H2
     
  4. Feb 5, 2009 #3
    Yes, this makes sense in regard to the setup of this device.

    According to the article,
    What about the idea of using radio waves to break the bonds? How would that work? I've seen various claims before, which include using resonance frequencies (not the claim here though), but have yet to see a reputable source of validation. From the appearance of this setup, my current thoughts include some quasi-electrolysis effect due to the ionic components of the solution and increased thermal agitation caused by radio waves.
     
  5. Feb 5, 2009 #4

    Ivan Seeking

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  6. Feb 6, 2009 #5
    Thanks for the link.

    The article link in the other thread actually discusses the same "discovery" as the one I posted in this thread.

    There is a lot of bad science in that article. First, the salt water does not ignite; it's the hydrogen and oxygen gases. Second, the energy inputs required to heat the water and create the gases require far more energy than usable energy outputted from the combustion of gases.

    Case closed.
     
  7. Feb 6, 2009 #6

    Ivan Seeking

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    Yes, but the point of linking the thread was the discussion that follows.

    Correct.
     
  8. Feb 6, 2009 #7
    The only use of sea water really, is in fusion fuel production, as said breaking down water into it's constituents is energy heavy.
     
  9. Feb 11, 2009 #8
    Simply, could you explain a proof for the energy variation. I can't understand why more energy is consumed than released. According to the law of conservation of energy " energy can not be created nor destroyed but it can be converted from one form to another"

    so Is there an explaination?

    thanks.
     
  10. Feb 11, 2009 #9

    mgb_phys

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    Yes to be strictly accurate you will get out exactly the same energy from the bond that you put in = conservation of energy.
    But the system as a whole will not be perfectly efficent, there will be waste heat for instance, so overall the machine will take more energy to split the water than you will get back when you burn it.
     
  11. May 6, 2010 #10
    That is true, but does it not apply to other fuels? How much energy is put into 1L of unleaded fuel from the moment they started drilling as crude, than transported and finaly refined and what you get after burned in a combustion engine? The engine does not use 100% of it either, is more what 16%?
     
  12. May 6, 2010 #11
    Yes its called HHO gas and of course it explodes... (better) burns but so does propane.
     
  13. May 6, 2010 #12

    CEL

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    If you consider the energy spent for drilling, refining and transporting fuel, it is of course less than the energy provided by burning the fuel, otherwise it would be stupid to do it.
    But the energy contained in crude oil comes from the organisms that originated it. Such organisms obtained their energy either from the Sun or by eating other organisms.
    Of course, the energy obtained by burning fuel is a tiny part of the solar energy used to generate it.
     
  14. May 6, 2010 #13
    yes, and its a pitty to burn the stuff anyway where a lot of it is lost as heat, better would be the use of fuel cells and if the water would be splitted into hho gas with help of the energy of wind and solar panels to feed the cells then it does not matter that much if you have to put more in then you get... wind and sun are for free...
    Something like this is a cool idea http://www.h2-vehicles.com/hydrogen-watercraft.htm [Broken]
     
    Last edited by a moderator: May 4, 2017
  15. May 6, 2010 #14

    Ivan Seeking

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    First of all, the stuff is H2 - hydrogen gas - not HHO. HHO is a popular term that refers a stoichiometric mixture of hydrogen and oxygen [two parts hydrogen, and one part oxygen]. Fuel cells want H2, not HHO. If you store HHO, you have a bomb.

    The idea that we can burn hydrogen in an engine, or use it in a fuel cell, isn't news to anyone. The problem is that the liberation of hydrogen, using electrolysis, is far too inefficient to be useful to produce fuel for combustion [to burn it in your car]. Perhaps it will make sense for fuel cells if and when the price of fuel cells come down. Right now they are fantastically expensive - much more than you would pay for fuel over the life of your vehicle.
     
    Last edited by a moderator: May 4, 2017
  16. May 6, 2010 #15

    CEL

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    Not only that. Producing hydrogen is expensive. Solar and wind power are alternative sources, to be used to complement other sources of electrical energy.
    In the far future (for decades it is promised for the next fifty years), when fusion power is available, people can build fusion plants in the ocean. These plants will extract deuterium from the water, to use in the reaction and can use the generated energy to split the water and obtain hydrogen, that will be shipped to the consumers.
    When this happens, I am sure that fuel cells will be cheap enough.
     
  17. May 6, 2010 #16

    Ivan Seeking

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    We will see. Right now, to me, fuel cells are a pipe dream. I see algae derived fuels [biodiesel and ethanol] a far more likely option. It may even make sense to burn hydrogen in combustion engines before fuel cells make sense.

    There is a group at MIT working to get hydrogen from algae.
     
    Last edited: May 6, 2010
  18. May 6, 2010 #17
    If that happens, I am investing heavily in platinum! I wonder if these cells will ever be used if there must be hydrogen in a tank, would that be a safety issue? Just as a pressure vessel I Would think it could be dangerous. Perhaps something that liberates hydrogen, much as lithium deuteride is used to liberate tritium, but without the KABOOM.
     
  19. May 6, 2010 #18

    mgb_phys

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    Yes, but so is a tank of gasoline.
    H2 is slightly safer than propane. But you are going to need some engineering on the nozzle so that a gas station attendant in New Jersey isn't wrenching regulators on 3000psi tanks.
    A couple of companies are looking at H2 absorbed onto a metal matrix, a few others are looking at liquid hydrogen.
     
  20. May 7, 2010 #19
    I am not claiming that hydrogen is dangerous and gasoline is not, there is a reason fuel-air bombs use what is essentially petrol. I was thinking more of the high pressure than the gas itself. I saw a funny video of a Thai "Anti smoking day" with this older gentleman cutting a large floating cigarette filled with balloons that had been mistakenly filled with H2! A spark from the metal ribbing ignited the hydrogen, blew a bunch of other balloons... and nobody was seriously hurt, just surprised. I cannot see this happening with gasoline, people would be terribly injured.

    I have some faith in engineering when it comes to pressure, and while a fireball is impressive, H2 burns so quickly it is better than burning gas which takes a car down to frame-rails! I like the idea of H2 absorption on metal, but either would be wonderful if electrolysis can be made efficient.
     
  21. May 7, 2010 #20

    mgb_phys

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    You can make the clyinders out of carbon fibre composites - there are a couple of compressed air prototype cars that do this and meet crash safety standards.
    High pressure industrial gas cylinders are massively over engineered and rarely fail, the weakspot is the valve/regulator assembly, I must admit I'm always nervous changing a regulator on a HP cylinder.
    But engineering a self sealing locking idiot proof connector isn't impossible

    There are a couple of problems with filling, if you do it quickly you have a heat issue - especially if the cylinder is embedded inside a car.

    Personally for a whole bunch of supply-chain efficency reasons I can't see H2 winning over LPG/LNG, if you are going to use energy to make H2 from water you might as well use the same energy to make CH4 from coal beds or grow algea.
     
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