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Making gasoline from seawater (to store energy)

  1. Apr 10, 2014 #1

    berkeman

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    This looks like it's mainstream work being done at the Naval Research Lab -- interesting stuff:

    U.S. Navy's new stealth destroyer
    http://www.cnn.com/2014/04/10/tech/innovation/navy-new-technology/index.html?hpt=hp_t2
     
    Last edited: Apr 17, 2014
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  3. Apr 10, 2014 #2

    Integral

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    I shared an article about that on our Facebook page a couple of days ago.

    Interesting stuff.
     
  4. Apr 10, 2014 #3

    berkeman

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    Does anybody have a link to the NRL research directly? I'll look when I have a chance...
     
  5. Apr 10, 2014 #4

    Ivan Seeking

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    Sounds cool but the bottom line [price] is what matters, and that still seems to be a pipe dream. Also, what is the net energy return? It is a long way from proof of concept in a lab to $3 a gallon.
     
  6. Apr 11, 2014 #5

    Astronuc

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    It sounds like Fischer-Tropsch synthesis in which one makes alkanes from CO2 or CO and H2.

    http://en.wikipedia.org/wiki/Fischer–Tropsch_process

    http://www.netl.doe.gov/publications/factsheets/rd/R&D089.pdf

    Press release from NRL (2012)
    http://www.nrl.navy.mil/media/news-releases/2012/fueling-the-fleet-navy-looks-to-the-seas

    There are apparently some patents out there
    http://www.wvcoal.com/research-development/us-navy-2014-co2-to-jet-fuel.html [Broken]


    F-T Synthesis was something I looked into about 20 years ago for some other reasons, but I was aware that it was the basis of synthetic fuel.
     
    Last edited by a moderator: May 6, 2017
  7. Apr 11, 2014 #6

    mfb

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    Then we still need an energy source for that. Well, looks like a great storage method if it works out.
     
  8. Apr 12, 2014 #7

    ZapperZ

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    I still want to know how much energy it takes to produce such a thing. If it uses more energy than it produces (yeah hydrogen fuel, I'm looking at YOU!), then this hasn't solved anything.

    Zz.
     
  9. Apr 12, 2014 #8

    Vanadium 50

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    Sure it has. An aircraft carrier is nuclear powered, but the aircraft are not, which requires the task force to carry a lot of jet fuel with it. If you could use the nuclear plant to make jet fuel - even inefficiently - you solve this problem. This saves you money on fuel, on ships to carry the fuel, on ships to protect ships that carry that fuel, and so on.
     
  10. Apr 12, 2014 #9

    Astronuc

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    I believe the plan has been to use solar (sunlight) as the energy source. Certainly power from a nuclear plant (in a carrier as V50 mentioned) would be a possibility.

    There is also waste heat in various process industries.
     
  11. Apr 12, 2014 #10

    ZapperZ

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    But the problem here is that if it comes directly from the grid, you need to make a variable estimate of how much you save, since the grid isn't exclusively from nuclear power, and the contribution from it varies from week to week. If this is plugged in directly from a nuclear power plant, then sure, even the hydrogen fuel will be beneficial.

    Zz.
     
  12. Apr 12, 2014 #11

    Astronuc

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    Certainly these are considerations.

    Nuclear is being considered for large scale hydrogen production, but one has to look at how much energy is required to make the usable form of chemical energy.

    I seem to remember that it used to take 1 barrel of oil to make 5 (or more), but now it's more like 1 to 3. That's fine if there is an unlimited source of oil.

    Ideally, solar energy (rather abundant) would be used to transform CO/CO2 and H2 into liquid fuels, which are more or less necessary for transportation, particularly aircraft and ships.

    Energy storage is another area of significant research.

    Even nuclear is limited, as are all fossil fuels. The only source of abundant energy is solar, which also drives wind and hydro, via the atmosphere. Geothermal is rather limited.
     
  13. Apr 12, 2014 #12

    mfb

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    Fusion energy would be limited as well, but the available amount is so gigantic that the limits are far away.
     
  14. Apr 16, 2014 #13

    Ryan_m_b

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    It definitely has the potential to solve a host of issues if we don't look at it as a way of producing power but instead of storing it. If a series of Fischer-Tropsch processes could be powered by source of renewable energy (PV for this purpose would be a form of artificial photosynthesis) then we would have solved a huge problem in energy storage that doesn't involve any significant reworking of the trillions of dollars of oil infrastructure world wide.

    This would probably come under chemical or electrical engineering. Would be interesting to see a discussion on it. We have a similar thread somewhere on algae fuel which could potentially do a similar thing, only using biological processes. There are even projects along these lines looking at using synthetic bacteria for the same effect.
     
  15. Apr 17, 2014 #14

    berkeman

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    (Moderator note -- thread moved to EE from the Mentor discussion forums...)
     
  16. Apr 17, 2014 #15
    Very interesting! There seems to be a lot of interest in this story from the people I've talked with.
     
  17. Apr 17, 2014 #16
    Definitely interesting, thanks for sharing this, you can tell the ships straight-line shape is designed to reduce the radar profile, in much the same way a stealth aircraft does. Rounded surfaces are an easy to detect profile.
     
    Last edited: Apr 17, 2014
  18. Apr 19, 2014 #17

    OmCheeto

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    You kids should hang out in the regular forum more often. :wink:

    My response:

    When I saw this the other day, my mind started racing.

    ps. Has anyone seen RonL lately? His obsession with compressors made absolute sense while my mind was spinning.
     
  19. Apr 21, 2014 #18

    sophiecentaur

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    I cannot imagine that seawater, with all its impurities, would be the best medium to use for a system like this. Pure water (or some controlled solution of chemicals) could easily be carried on a ship and, of course, recycled within the cycle of energy storage and use.
     
  20. Apr 21, 2014 #19
    ships are already designed with condensers to extract fresh water from sea water, the amount of fresh water a ship needs to carry for a 6 month NATO voyage is simply impossible. This is simply an extension to the sea water processing they already do. FWI they also process human waste and bilge water through a waste water processing system. For the bilge water which invariably has oils mixed in they utilize a centrifuge. The human waste treatment system is one that does not require settling times and a flocculant. Usually it uses a cathodic electrical system to kill any bacteria etc. Coincidentally the salt extracted for fresh water can be used to support the waste water treatment system

    lol ever have a 1 minute Pusser shower? wet turn off water, lather, rinse in less than 1 minute of water use
    Your right that seawater is probably not the best medium to use but its readily available, reduces storage, and is already being processed for ship use in numerous ways. Liquid storage on ships reduces ship stability as liquids slosh around and tend to add rocking motion to a ship. Modern ships now use a baffling tanks system where any remaining volume on a ship is filled with sea water to keep them 95% full at all times. This helps lower a ships center of gravity which is essential for ship stability
     
    Last edited: Apr 21, 2014
  21. Apr 21, 2014 #20

    SteamKing

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    It's not clear, but I think the poster is referring to 'ballast' tanks. 'Baffling' is a means whereby large tanks have light, somewhat open baffle plates fitted inside to control the sloshing motion of fluid contents when the tank is partially filled.

    Many years ago, small combatants, like destroyers, suffered a reduction in stability as they burned off fuel. To counteract this, the USN came up with a system whereby fuel tanks would be piped to allow the fuel tank to admit seawater as the fuel was taken from the tank, since the fuel would float on top of the water. At this time, naval vessels burned heavy residual fuel, and there were no pollution regulations to speak of.

    Now, conventionally powered naval vessels burn distillate fuels (similar to diesel fuel), whether the plant is steam, gas turbine or diesel, and needless to say, there are pollution regs out the wazoo. Ballasting of fuel tanks is no longer permitted (indeed it is prohibited), nor is it desirable from the standpoint of contamination of the fuel system of a vessel.

    Even commercial oil tankers, which once would add ballast to cargo tanks if they happened to be traveling light or needed the ballast for structural reasons, now must be constructed to use segregated ballast tanks, which are separate from all cargo or fuel tanks.

    The trick to maintaining vessel stability with large numbers of liquid tanks is to keep the tanks as small as practicable and to keep the number of partially filled tanks to a minimum at all times.
     
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