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The Military Transportation Science Technology

Navy Creates Fuel From Seawater 256

New submitter lashicd sends news that the U.S. Naval Research Laboratory has announced a successful proof-of-concept demonstration of converting seawater to liquid hydrocarbon fuel. They used seawater to provide fuel for a small replica plan running a two-stroke internal combustion engine. "Using an innovative and proprietary NRL electrolytic cation exchange module (E-CEM), both dissolved and bound CO2 are removed from seawater at 92 percent efficiency by re-equilibrating carbonate and bicarbonate to CO2 and simultaneously producing H2. The gases are then converted to liquid hydrocarbons by a metal catalyst in a reactor system. ... NRL has made significant advances in the development of a gas-to-liquids (GTL) synthesis process to convert CO2 and H2 from seawater to a fuel-like fraction of C9-C16 molecules. In the first patented step, an iron-based catalyst has been developed that can achieve CO2 conversion levels up to 60 percent and decrease unwanted methane production in favor of longer-chain unsaturated hydrocarbons (olefins). These value-added hydrocarbons from this process serve as building blocks for the production of industrial chemicals and designer fuels."
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Navy Creates Fuel From Seawater

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  • They do. (Score:5, Insightful)

    by jcr ( 53032 ) < .ta. .rcj.> on Wednesday April 09, 2014 @02:29AM (#46702335) Journal

    All US carriers are nuclear-powered, and being able to synthesize aviation fuel would drastically reduce the logistics cost of operating them.


  • by popo ( 107611 ) on Wednesday April 09, 2014 @02:44AM (#46702389) Homepage

    No. Nothing like nuclear fusion. This is not an energy source. It is a fuel source.

  • by wonkey_monkey ( 2592601 ) on Wednesday April 09, 2014 @03:28AM (#46702529) Homepage

    I think that's sort of what the GP is getting at. It's a fuel source, not an energy source.

    It takes more energy to make hydrocarbons from water and CO2 than you get when you burn the hydrocarbons.

    What about the energy currently required to keep ships stocked up on aviation fuel, though?

  • by multi io ( 640409 ) <> on Wednesday April 09, 2014 @03:34AM (#46702543)

    By the time you're going to all of this trouble to turn electricity into fuel, it is unlikely that you'd want to run a car on it - you'd rather just have an electric car.

    Not sure about that. Electrical energy can't be stored easily -- you need some high-tech battery with all kinds of electrolytes and complicated chemicals, and still the capacity is relatively measly. Electricity works much better if it can be consumed right after it is produced, without storing it (but if this can be achieved, electricity is otherwise very flexible -- it can be scaled up and down easily, and it can be transported quickly over long distances). HC fuels OTOH work well for storing energy -- they already store it, you just have to pour them into any airtight vessel, and they'll stay there until you burn them. So electricity and HC fuels might compliment each other quite well if the right technologies are in place. Any process that can convert electricity into fuel (and also happens to consume and thus neutralize the byproduts of burning the fuel) should be almost like a gold mine, if it can be scaled up sufficiently. So if this water-to-fuel conversion or similar processes can be made to work efficiently, chances are liquid fuels will continue to be the preferred method for large-scale mobile energy consumption needs.

  • Re:They do. (Score:5, Insightful)

    by CodeBuster ( 516420 ) on Wednesday April 09, 2014 @04:11AM (#46702643)
    There's no doubt that manufacturing fuel on board is desirable from a logistics standpoint. The question is cost, not just monetary but energy. As you're no doubt aware, hydrocarbon fuels are incredibly energy dense which means that an equal amount (and probably more) energy most go into their creation from scratch using the most basic raw materials, H2, CO2 and CO. The question is how much space is available onboard for production scale versions of these reactors and how much steam and electric power will the reactor have to supply to make this work. I don't know, but I would guess lots. This fuel production sounds like an energy hungry process. How much power and steam can be spared from other onboard needs to power fuel production? Would this stress the reactors, possibly reducing service life or requiring more frequent nuclear refuels? There are trade-offs here, it's not a slam dunk.
  • by Joce640k ( 829181 ) on Wednesday April 09, 2014 @05:40AM (#46702887) Homepage

    At least it's part of a CO2 cycle, not some new CO2 we dug out of the ground.

  • Re:They do. (Score:5, Insightful)

    by flyingsquid ( 813711 ) on Wednesday April 09, 2014 @06:04AM (#46702975)

    There's no doubt that manufacturing fuel on board is desirable from a logistics standpoint.

    Is it, though? If you run out of fuel, just refuel the damn thing. At sea refueling is trivially easy, all you need is a ship that can carry a lot of fuel, a pump, and a hose. Pretty much any ship will work if it will carry enough- for example in the summer fishing season in Alaska, the canneries hire on the big Bering Sea crab boats to act as tenders, and they provide fuel to the smaller salmon boats. Refueling a destroyer at sea isn't all that different except in scale, and the Navy has logistics ships designed specifically to do this.

    The other variable that needs to be considered is time. I'm guessing that not only is this process very energy-intensive, it takes a while. The article shows them fueling a hobby plane with the fuel they've generated, which suggests they're not exactly churning the stuff out by the barrel. Unless you can create a system that can deliver tens of thousands of gallons a day, it's probably going to be far faster to divert a support ship and have it show up with 7 million gallons of the stuff.

    And realistically, when is a carrier or other ship likely to be far from supply lines? Current and potential flashpoints would include places like Syria, the Ukraine, Iraq, Iran, Afghanistan, Pakistan, Taiwan, and North Korea. Likely areas of operation for the Navy will be the Mediterranean, Arabian Sea, South China Sea, and the Sea of Japan. None are far from civilization. Not coincidentally, the U.S. already has bases near all of these places. The U.S. Navy did have a tough time in the Pacific theater in WWII, trying to fight the Japanese in Indonesia on the far side of the Pacific, and that was even after they had the good fortune that the Japanese didn't think to bomb the fuel tanks in Hawaii. Part of what they learned from Pearl Harbor is that you don't wait until the fighting starts to establish a supply chain and stockpile fuel.

  • by itsdapead ( 734413 ) on Wednesday April 09, 2014 @06:08AM (#46702989)

    Chlorine gas is toxic. It was used in shells to poison troops in WW1.

    Whereas both hydrogen and oxygen are perfectly safe and have never been known to case any sort of problem whatsoever... well, ok, there was the Hindenburg, and Apollo 1, and...

    So if you do the described experiment while locked in a badly-ventilated room, leave it running for long enough to increase Ever Ready's share price by 1%, ignore the eye-watering stink that even a whiff of chlorine will produce and then light a cigarette, you could be in real trouble. If only from all the crap in the cigarette smoke...

    However, all this pales into insignificance alongside the experiment's reckless use of the liquid death that is Dihydrogen Monoxide []!

    Seriously, guys, when everything is described as dangerous, nothing gets treated as dangerous. If you're not sure what it is, don't wait for someone on the internet to tell you not to snort it.

  • by mysidia ( 191772 ) on Wednesday April 09, 2014 @06:33AM (#46703063)

    4th grader in what country? Your USA-centrism is showing.

    In other first world countries; any 2nd grader should know this.

  • Re:They do. (Score:4, Insightful)

    by pupsocket ( 2853647 ) on Wednesday April 09, 2014 @06:46AM (#46703107)

    Japan, like most of civilization, is not a fuel source, just a fuel depot. A foreign base is an advantage and a disadvantage, an overhead expense, a sore in foreign relations, and a vulnerability requiring additional defense.

    As far as supply lines go, this is like taking off the pump-fed diving suit and breathing with gills.

    Your point is well taken if this process is just an auxiliary. But if every vessel in an armada can refill from purpose-built reactor-powered saltwater-crackering seaworthy catalytic beds, then it's a much different force, one that can't be stopped at the Solomon Islands.

  • by smash ( 1351 ) on Wednesday April 09, 2014 @07:00AM (#46703145) Homepage Journal
    You realise that doesn't make it a FOSSIL fuel right?
  • Re:They do. (Score:5, Insightful)

    by drinkypoo ( 153816 ) <> on Wednesday April 09, 2014 @07:46AM (#46703327) Homepage Journal

    There's no doubt that manufacturing fuel on board is desirable from a logistics standpoint.

    Is it, though? If you run out of fuel, just refuel the damn thing. At sea refueling is trivially easy, all you need is a ship that can carry a lot of fuel, a pump, and a hose.

    And a supply line for those ships, and all the military vessels that entails. If you don't need the supply line, then you can project force with many fewer vessels.

  • Re:liquid hydrogen (Score:5, Insightful)

    by khallow ( 566160 ) on Wednesday April 09, 2014 @08:26AM (#46703535)

    china's plan to convert coal to hydrogen to methane is about 50 percent energy efficient. For big commercial aircraft, it will be better to use liquid hydrogen directly.

    The problem with this is that it's cryogenic with an extremely low boiling point of 20 K (Kelvin). You would have to carry a much heavier tank and insulation for the liquid hydrogen on the aircraft. There's also hydrogen leaks and transport of it to the airport from wherever it is produced.

    You would also need to handle boil off of hydrogen while the plane is on the ground and the hazards of handling extreme cryo fluids, which is much more dangerous than handling jet fuel/kerosene. For example, oxygen condenses at 50 K meaning a poorly insulated tank (say due to damage inflicted while conducting maintenance) could be condensing liquid oxygen inside the plane's wing.

    Further, there isn't a good reusable tank material for handling liquid hydrogen. Composites weaken over time due to gas pockets in the composite material (and thermal cycling) while metals such as aluminum are subject to hydrogen embrittlement.

    I think there would be a huge redesign of aircraft in order to use liquid hydrogen directly. Thicker wings say from a flying wing design would be more fuel efficient.

    There would probably also be huge logistics changes. Fuel tanks would probably have to be kept at extreme cryo temperatures indefinitely (including overnight) in order to prevent thermal cycling. You couldn't have the aircraft sit on the tarmac for hours because it would either lose too much fuel due to boil off or require considerable refrigeration power to keep boil off from happening. A traffic jam combined with a hot day and loss of grid power, would be a disaster for an airport.

    Meanwhile methane can be converted to normal jet fuel with some additional loss of energy. For example, a coal burning plant/refinery on site of a coal mining operation could produce methane or longer chain hydrocarbons directly.

    And at the current state of affairs, the cheapest hydrogen source is methane. Any plan for creating hydrogen from water is going to run into a similar degree of energy loss as that of converting coal and water to methane and syngas.

  • by Talderas ( 1212466 ) on Wednesday April 09, 2014 @08:38AM (#46703607)

    If it was widespread and viable it means the fuel is coming out of the ocean rather from underground. So the carbon being released into the air would be the very sort of carbon that is being trapped in the oceans rather than stuff that's been locked underground for millions of years.

  • Re:Energy (Score:2, Insightful)

    by Anonymous Coward on Wednesday April 09, 2014 @08:39AM (#46703609)

    Storing electricity in burnable liquid form probably *is* the breakthrough in electrical storage...

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