Tech News: U.S. Navy Reports Developments RE: Converting Seawater To Fuel

[clsage]

Sharing this here because, even though the tech is totally different, in candor it reminded me of the old 'starships diving into gas giants to refuel' trope from various SF stories and/or games (eg: The Mote In God's Eye and the game which appears to have derived from it 'Traveller' (the classic version with the little black books)). Of course, it also has some plot hook usages in other genres as well.

 

http://news.yahoo.com/us-navy-game-changer-converting-seawater-fuel-150544958.html

 

-Carl-

[Vondy]

I did some digging and the cost per gallon in the lab is somewhat high, but the Navy's projections for cost once efficiencies are tweaked for real-world production run between $.79 and $1.21 per gallon. Also, the tech is almost identical to the tech proposed to scrub hydrocarbons from the atmosphere. However, the Navy's projected cost per metric tonne is $114 compared to the commonly used $559. I suspect this is because 1) hydrocarbons are more easily soluble in water, and 2) are significantly more concentrated in our seas. On the other hand, focusing on cleaning up the seas seems more efficient -- and is ultimately where the airborne hydrocarbons end up. A sword that can double as a ploughshare -- scrubbing the high seas clean of hydrocarbons and the enemy in one deft stroke! On the other hand, we would need more scrubbers than just our fleets engines to do it. The estimated cost to get us to target levels would be a trillion dollars spread over a century. On the other hand, we blew that in a decade on Iraq -- so one could argue its just a question of priorities. It is cool though. And, soon we'll have RAIL GUNS to boot!

[Old Man]

Speaking of railguns, http://bgr.com/2014/04/08/u-s-navy-railgun-video/

 

Deploying in 2016.

[Old Man]

I wonder if the seawater-fuel technology could be scaled up to the point where it could be used to remove significant amounts of greenhouse gases from the sea, which absorbs it from the air.

[Cancer]

Interesting suggestion. What I don't know is how fast the atmosphere-ocean connection for gas exchange is in the oceans. That is akin to asking the mixing timescale between different parts of the ocean, and there's significant vertical structure.

[Old Man]

I think the atmospheric-oceanic diffusion is pretty well known, at least at the surface; shallow water CO2 concentrations appear to follow atmospheric changes on the order of 3-4 years.  How CO2 diffuses vertically through the water column is less well known, so we don't know how long or how well the seas will continue to suck CO2 out of the atmosphere.  But most of the reefs and fish I'm concerned with are in shallow water anyway.

 

I'm probably dreaming, given the sheer amount of CO2 that gets shot into the air on an annual basis.  But I've reached the conclusion that just reducing or eliminating fossil fuels probably isn't going to be enough, even if it were possible, and that mankind will have to remove CO2 from the atmosphere directly.  So far the most efficient means of doing that that I've found is through sequestration of biochar--taking crop waste, which removed a great deal of CO2 from the air during growth, burning it for energy, and capturing the resulting char and gaseous CO2.  But using this seawater process as an energy-positive method of extracting and containing CO2 could add to that.  If it scales up.

[Old Man]

Did some digging and found a 2009 report on the same people.  What they were doing then was experimenting with the Fischer-Tropsch process, using an iron-based catalyst to reduce the amount of unwanted methane in the output hydrocarbons.  But it appears that this latest breakthrough occurs before that process, in getting the CO2 and H2 out of the water to begin with.  No details on that that I can find yet.

[Vondy]

I wonder if the seawater-fuel technology could be scaled up to the point where it could be used to remove significant amounts of greenhouse gases from the sea, which absorbs it from the air.

 

One article I read indicated the answer was "yes." And, the fuel could be used to power other ships, or maybe cars -- which would mitigate operating expenses. One of the benefits of the Navy program is that they don't have to replace the engines on the ships these units would operate on. Some engineers familiar with the Navy tech speculated it could be scaled up and placed on a platform akin to an oil drilling platform -- which would also allow you to suck up deeper water if need be. But, for that to happen, you need investment dollars -- from government or business.

[Old Man]

Okay, I found a better article: http://www.nrl.navy.mil/media/news-releases/2014/scale-model-wwii-craft-takes-flight-with-fuel-from-the-sea-concept .  With a headline about a model airplane. 

 

Anyway, the new development seems to be a new electrolytic cation exchange module (E-CEM). I can't find any details on how it works, but producing gaseous CO2 and H2 from seawater at 92% efficiency is unreal.

[Christopher]

On the other hand, focusing on cleaning up the seas seems more efficient -- and is ultimately where the airborne hydrocarbons end up. A sword that can double as a ploughshare -- scrubbing the high seas clean of hydrocarbons and the enemy in one deft stroke!

No, this sword won't remove the Gasses. It only takes them out of the water to immediately put it back into the air. Where they just go into the water again.

 

I wonder if the seawater-fuel technology could be scaled up to the point where it could be used to remove significant amounts of greenhouse gases from the sea, which absorbs it from the air.

That would still leave the question store it. Remeber that Oil was a source of Hydrocarbons sealed under the earth, before we tapped into it. If we just take it out to isntantly use it we just found a way to recycle our fuel exhaust - to make it new exhaust.

While we would need less new fuel from Oil, we would not actually reduce the Greenhouse gasses already around - only how much new gasses we add.

[Vondy]

No, this sword won't remove the Gasses. It only takes them out of the water to immediately put it back into the air. Where they just go into the water again.

 

Strange that non-navy environmental scientists who analyzed the technology all concurred it would have a positive effect.

 

I'll take the published, paid and non-biased pros opinion over pixels on a message board *every time.*

[Christopher]

Strange that non-navy environmental scientists who analyzed the technology all concurred it would have a positive effect.

 

I'll take the published, paid and non-biased pros opinion over pixels on a message board *every time.*

Please reference them. I would like to know the logic/math/physics behind that.

 

In Layman terms "Hydrocarbon" is what makes Oil, Coal and Earthgasses and the like a good Fuelstuff. It's the single most prevelant source of energy of our day (until Fusion power get's around).

 

Also we need to exclude that this "recycled" energy it is just another "Fake Clean Energy" thing like the Fuel Cells. Thier use might not produce any greenhouse gasses, but it is not an energy source. It's an energy storage. And the production and transportation of said energy creates signicant amounts of the greenhouse gasses (again, until Fusion comes along for the cheap & clean electricity).

[BlueCloud2k2]

There are other uses for oil besides fuel.

 

Plastics come to mind.

 

Maybe sequester  the carbon itself for carbon nanotube?

[Old Man]

Please reference them. I would like to know the logic/math/physics behind that.

 

In Layman terms "Hydrocarbon" is what makes Oil, Coal and Earthgasses and the like a good Fuelstuff. It's the single most prevelant source of energy of our day (until Fusion power get's around).

 

Also we need to exclude that this "recycled" energy it is just another "Fake Clean Energy" thing like the Fuel Cells. Thier use might not produce any greenhouse gasses, but it is not an energy source. It's an energy storage. And the production and transportation of said energy creates signicant amounts of the greenhouse gasses (again, until Fusion comes along for the cheap & clean electricity).

 

No one is claiming this is a new source of energy.  It's big for the Navy because it would let them use their reactor-equipped vessels to turn seawater into oil for non-nuclear ships while at sea. 

 

My own interest is as a means of removing carbon from the seas and thereby countering climate change.  Taking CO2 out of the oceans at 92% efficiency would make carbon sequestration much more cost effective. 

[Teflon Billy]

No one is claiming this is a new source of energy.  It's big for the Navy because it would let them use their reactor-equipped vessels to turn seawater into oil for non-nuclear ships while at sea. 

 

My own interest is as a means of removing carbon from the seas and thereby countering climate change.  Taking CO2 out of the oceans at 92% efficiency would make carbon sequestration much more cost effective. 

What I think would be awesome is if they created nuclear power super-tankers that just sit off the coast (or wherever is the most advantageous) and churn through sea water until they are full and then return to port, offload, wash, rinse, repeat.

 

TB

[Old Man]

That would be pretty cool, although I wonder if it wouldn't be more efficient to just put the reactor onshore. 

[Lawnmower Boy]

Indeed. Once we have the cheap energy, this will be how we solve all the world's problems. CVNs take us a short step along the way. The process, and an atmospheric equivalent, are even more promising. There are many places around the world with hydroelectric, wind, or solar capacity that cannot be feasibly tapped due to transmission distances (or the fact that they're on remote desert islands) that could be used to put oil back into our petroleum based logistical infrastructure. However, as I imagine how my favourite project (a plant at the abandoned hydroelectric dam at Ocean Falls) would work, I can see the advantages of the CVN project. There are pretty serious ecological implications if all the dissolved carbon dioxide in a relatively constricted body of water is extracted, I should think. 

[Teflon Billy]

I honestly feel that solving Global Warming is not going to be one of fossil fuel use reduction but of engineering. Engineering projects that will scrub the atmosphere clean, because unless we all want to take a giant step back and involve a whole lot of starvation and death, we aren't going to get there by cutting carbon emissions (at least not in the way the Greenies want us to, and it isn't going to be by solar or wind either.)

 

Nuclear reactors for cheap abundant energy used to power the machines that will efficiently (probably involving as yet undiscovered catalysts) pull the atmostpheric polutants out of the atmospher, as well as purify sea water, and a whole host of other environmental issues.

 

Cheap power, that is the thing that we should be focusing on IMO.

 

TB

[TheQuestionMan]

Brilliant

[BlueCloud2k2]

Agreed!