Making gasoline from seawater (to store energy)

[berkeman]

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

Researchers at the U.S. Naval Research Laboratory, Materials Science and Technology Division, said this week they have demonstrated proof-of-concept on the ability to draw carbon dioxide and hydrogen from seawater and turn it into forms of gasoline.

Heather Willauer, a Naval Research Laboratory chemist, called the technology "game changing."

"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," she said in a statement.

The lab's researchers used "an innovative and proprietary NRL electrolytic cation exchange module" to remove the carbon dioxide from the water and produce hydrogen gas in the process.

"The gases are then converted to liquid hydrocarbons by a metal catalyst in a reactor system," the research lab's statement said.

The fuel produced was used to power the engine of a small model aircraft, the researchers said.

The process could be ramped up to produce a replacement for jet fuel at a cost of $3 to $6 per gallon within a decade, the researchers said. That step would come on land, with versions to be used on ships coming later, they said.

 

[Integral]

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

Interesting stuff.

 

[berkeman]

Does anybody have a link to the NRL research directly? I'll look when I have a chance...

 

[Ivan Seeking]

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.

 

[Astronuc]

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 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.

 

[mfb]

Then we still need an energy source for that. Well, looks like a great storage method if it works out.

 

[ZapperZ]

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.

 

[Vanadium 50]

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.

 

[Astronuc]

Then we still need an energy source for that. Well, looks like a great storage method if it works out.

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.

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.

 

[ZapperZ]

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.

 

[Astronuc]

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.

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.

 

[mfb]

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.

Fusion energy would be limited as well, but the available amount is so gigantic that the limits are far away.

 

[Ryan_m_b]

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.

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.

 

[berkeman]

(Moderator note -- thread moved to EE from the Mentor discussion forums...)

 

[Greg Bernhardt]

Very interesting! There seems to be a lot of interest in this story from the people I've talked with.

 

[Mordred]

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.

 

[OmCheeto]

(Moderator note -- thread moved to EE from the Mentor discussion forums...)

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

Sorry about the long response.
Both articles state the efficiency is about 60 %, but if the input power was was surplus,
it had little value anyway.
http://www.greencarcongress.com/2013/06/audi-20130625.html
http://www.fraunhofer.de/en/press/research-news/2010/04/green-electricity-storage-gas.html
http://www.nrl.navy.mil/media/news-releases/2012/fueling-the-fleet-navy-looks-to-the-seas

My response:

...
SWEET!
...

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.

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.

 

[sophiecentaur]

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.

 

[Mordred]

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.

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

 

[SteamKing]

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

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.

 

[Mordred]

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.

thanks I couldn't recall the correct tank term, lol been over 15 years since I last served on ship

 

[sophiecentaur]

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

I see. So it's not actually "seawater" that's used but water obtained from the sea. I could just imagine a steady need for replacement of corroded pipes, valves and pumps etc..

 

[Mordred]

I see. So it's not actually "seawater" that's used but water obtained from the sea. I could just imagine a steady need for replacement of corroded pipes, valves and pumps etc..

definitely, I don't know the exact specifications of the amount of salt needed for the fuel process but the waste treatment needs a 7% brine solution. Which provides a better conductor than fresh water. Plumbing on ships is a continuous repair, both from salt and from stresses due to translational shock from waves. Soft solder is never used as it cannot handle the shock so they use silver solder and a copper nickel mix piping on most but not all plumbing systems.

 

[nsaspook]

Navy background document for this research.
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA539765

I can see how it would be useful if you already have a power source with excess power idling but having a refining plant inside a already packed ship, using tens of megawatts of electrical energy to generate volatile pumped ethylene, propylene, and butylene (with methane byproducts) compounds as the base carbons for the (relatively safe) complex fuel hydrocarbons might be quite a risk because fuel fires were the #1 thing we trained on in Navy fire fighting school. Heavy fuel fires are dangerous but manageable because there is rarely an explosion from the fuel itself but the primary catalyst products here are easy to react and oxidize back to CO2 and water.

 

[Mordred]

nice article, covers a lot of the details thanks

 

[f95toli]

I see. So it's not actually "seawater" that's used but water obtained from the sea. I could just imagine a steady need for replacement of corroded pipes, valves and pumps etc..

Presumably they use titanium parts. Very expensive to install but save money in the long run. My dad works for the oil industry in Norway, they use titanium for everything including the plumbing on the housing platforms (hes had an interesting career: he started out as a domestic plumber but is now an engineer responsible for installing pipes on gas/oil platforms).

 

[dipole]

What is the waste product, carbon dioxide? If so, then this may help solve some issues, but it just adds to others.

 

[Astronuc]

I see. So it's not actually "seawater" that's used but water obtained from the sea. I could just imagine a steady need for replacement of corroded pipes, valves and pumps etc..

There are a number of advanced stainless steels, e.g., 254 SMO, 654 SMO, AL-6XN, (these are 6 Mo stainless steels, which have been around more than 20 years) etc, that are resistant to corrosion in chloride and NaCl solutions, i.e., seawater. These alloys are used in marine structures as well as on-shore distillation systems for extracting potable (fresh) water from seawater.

Navies have a long history of extracting water from seawater, and submarines extract water and oxygen from seawater while submerged. Obviously, nuclear powered submarines use electricity from the nuclear plant to run the processes.

 

[Astronuc]

What is the waste product, carbon dioxide? If so, then this may help solve some issues, but it just adds to others.

Burning aviation (fossil) fuel generates CO₂ and H₂O, and the Fischer-Tropsch synthesis takes energy and reverses the process, i.e., CO₂ + H₂ => C_xH_2x+2 + water, with the intermediate process of H₂O to H₂ + O₂.

It's a closed loop for the chemical process. On the other hand, there needs to be an energy source.

Liquid fuels are simply a medium in which chemical energy is stored.

 

[mheslep]

... submarines extract water and oxygen from seawater while submerged. Obviously, nuclear powered submarines use electricity from the nuclear plant to run the processes.

Do they? AFAIK subs recycle, i.e. they purify their grey water and scrub CO2 out of the air.

 

[sophiecentaur]

Reverse osmosis is much less energy consuming than electrolysis so you are probably right. What scrubbing process would be used? I don't know a lot about that sort of Chemistry.

 

[SteamKing]

Do they? AFAIK subs recycle, i.e. they purify their grey water and scrub CO2 out of the air.

You run a steam plant, you want to have a water-maker somewhere aboard. Even the old diesel-driven fleet boats from WWII had water-makers aboard, not for making potable water so much but for maintaining the acid in the batteries used to drive the vessel while submerged.

http://www.fleetsubmarine.com/fresh_water.html

The regulations governing the discharge of greywater from USN vessels are currently evolving, with the goal being to minimize the amount of solid waste and untreated liquid waste which is discharged during operation, but that doesn't necessarily mean that the grey water is re-cycled back into the potable water or feed water systems.

Most shipboard water-makers are of the 'flash' type, where seawater is fed into a low-pressure chamber, in which the water flashes into vapor, leaving a concentrated brine behind. The brine is dumped and the flashed vapor is condensed back to liquid water, without the salt.

 

[OmCheeto]

...
Liquid fuels are simply a medium in which chemical energy is stored.

Interesting.

 

[BigWill]

seawater is a natural electrolyte and sunshine a natural source of power

 

[sophiecentaur]

seawater is a natural electrolyte and sunshine a natural source of power

Does the adjective "natural" make it an engineering proposition? Its only advantage is that it's cheap to obtain (if you happen to live near the coast).