The US Navy's Seawater-to-Fuel Breakthrough

[Nice Squirrel]

http://www.nrl.navy.mil/media/news-...t-takes-flight-with-fuel-from-the-sea-concept

Navy researchers at the U.S. Naval Research Laboratory (NRL), Materials Science and Technology Division, demonstrate proof-of-concept of novel NRL technologies developed for the recovery of carbon dioxide (CO2) and hydrogen (H2) from seawater and conversion to a liquid hydrocarbon fuel.

Fueled by a liquid hydrocarbon—a component of NRL's novel gas-to-liquid (GTL) process that uses CO2 and H2 as feedstock—the research team demonstrated sustained flight of a radio-controlled (RC) P-51 replica of the legendary Red Tail Squadron, powered by an off-the-shelf (OTS) and unmodified 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.

"In close collaboration with the Office of Naval Research P38 Naval Reserve program, NRL has developed a game changing technology for extracting, simultaneously, CO2 and H2 from seawater," said Dr. Heather Willauer, NRL research chemist. "This is the first time technology of this nature has been demonstrated with the potential for transition, from the laboratory, to full-scale commercial implementation."
- See more at: http://www.nrl.navy.mil/media/news-...uel-from-the-sea-concept#sthash.hBdmIZu5.dpuf

Could this mean the end of dependence on oil?

 

[Coleman Smith]

Naw, Exxon will just buy the patent and kill the project.

 

[NobleSavage]

The process of conversion requires more energy than is given off by the burning of the liquid hydrocarbons. It would only work on nuclear powered Navy vessels that have that extra energy. The point is to make liquid fuel for the jets. Right now the aircraft carriers have to be resupplied by tankers. It's a win for logistics not necessary oil dependance. Theoretically, we could replace our fossil fuel use with this but it would be A LOT more expensive at the pumps and we have to set up new energy plants (nuclear maybe) to act as the input.

 

[GenesisNemesis]

I know there's a lot of water on Earth, but how could sea level be affected by this, if at all?

 

[beero1000]

I know there's a lot of water on Earth, but how could sea level be affected by this, if at all?

Almost certainly not at all.

 

[ramoss]

Not immediately. First, it has to be scaled up. Next, the 'price' of a gallon of the fuel is estimated to be between 3 and 6 bucks... so that is a bit on the expensive side. it will be economical for the Navy, since they won't have to worry about refueling ships doing transfers at sea, or having ships interrupt their mission to fuel for the smaller vessels.

However, eventually it will be a game changer. The price of oil will go up, because the oil that is left will be harder to extract. The cost of hydrogen production is going down (there are several technologies in development now that can make hydrogen production much cheaper). .. and when it comes to the source of CO2, the navy is extracting it from sea water, and the on land sources probably will be cheaper. It all depends on the final cost of scaling it up, and how other technologies emerge. It will make life interesting, that is for sure.

 

[skepticalbip]

I know there's a lot of water on Earth, but how could sea level be affected by this, if at all?

The only loss of water would seem to be from any Hydrogen that accidentally escaped during the process. The process takes water and CO2 to make the hydrocarbon fuel then when the fuel is burned water and CO2 (and heat) are produced. The water eventually ends up in the oceans again.

Pretty much a cycle: Use water, CO2, and energy to make a hydrocarbon fuel. Burn the fuel and you get back the water, CO2, and some of the energy.

 

[travc]

The process of conversion requires more energy than is given off by the burning of the liquid hydrocarbons. It would only work on nuclear powered Navy vessels that have that extra energy. The point is to make liquid fuel for the jets. Right now the aircraft carriers have to be resupplied by tankers. It's a win for logistics not necessary oil dependance. Theoretically, we could replace our fossil fuel use with this but it would be A LOT more expensive at the pumps and we have to set up new energy plants (nuclear maybe) to act as the input.

This sort of apparent ease and efficiency making energy dense and easy to use fuel is a big deal though.
Fuel != energy... Fuel always has less energy than what went into creating it. However, making fuel is a real problem. What we really want is a way to generate energy using whatever method is best / most efficient at a particular location and convert it into a common fuel... and this method seems to fit that bill nicely.

 

[G O R T]

I know there's a lot of water on Earth, but how could sea level be affected by this, if at all?

Worldwide, over 90 million barrels of oil are being used as fuel every day.
How much water is that creating?
Anyone know pounds of fuel > pounds of water?

 

[NobleSavage]

A 2010 report estimated that in order to produce 100,000 gallons of jet fuel in a day—assuming the process is 100 percent efficient—“the minimum amount of seawater that must be processed is 8,900,000 cubic meters. This is equivalent to a cube of seawater that is about 200 meters on each side.”

In real life, you’d expect the cube of seawater you'd need to be twice that size, which is a lot of liquid.

http://www.vice.com/read/can-we-really-fly-planes-on-seawater

 

[bilby]

I know there's a lot of water on Earth, but how could sea level be affected by this, if at all?

Worldwide, over 90 million barrels of oil are being used as fuel every day.
How much water is that creating?
Anyone know pounds of fuel > pounds of water?

Roughly the same volume of water is generated as the volume of fuel burned - once it cools to standard temperature and pressure.

Using isooctane as an example hydrocarbon fuel, we have:

2C₈H₁₈ + 25O₂ -> 16CO₂ + 18H₂O

The approximate masses are (g/mol):
H=1
C=12
O=16

so that's:

228g Octane + 800g Oxygen -> 704g Carbon Dioxide + 324g Water

Now Octane has a density of about 703kg/m³, and water is 1000kg/m³, so the volumes of liquid at STP on each side, when burning 1000 moles of octane are:

Octane = 228kg @ 703kg/m³ = 0.324m³
Water = 324kg @ 1000kg/m³ = 0.324m³

So burning 90 million barrels of octane fuel generates about 90 million barrels of water. (90 million barrels is about ten million cubic metres, which is a minuscule fraction - one part in a hundred billion - of the 1.3 billion cubic kilometres of the world's oceans).

If all of the world's 90 million barrels a day came from seawater, and averaged a year before being burned as fuel and returned as rain, the resulting drop in ocean levels would be microscopic; certainly far less than the natural variation in ocean levels due to global temperature fluctuations, even before we consider global warming.