9 ms·

Making Jet Fuel From Seawater While at Sea

72 points by joe24pack 14y ago

gunn 14y ago
Okay great. Where does the energy come from?
- landryraccoon 14y ago
  If it's an aircraft carrier, probably the nuclear power plant on board.
  - pixie_ 14y ago
    Yep, it's a pretty good use of 200MW of power when you're just sitting around in the ocean.
    - dctoedt 14y ago
      > when you're just sitting around in the ocean Watch any of the documentary series about life aboard an aircraft carrier [1] and you'll see that there's essentially no "just sitting around in the ocean." But your main point is still accurate: If there's power available, putting it to work making jet fuel might be a good trade-off for the additional drain on the nuclear fuel. [1] E.g., http://www.pbs.org/weta/carrier/ http://www.pbs.org/weta/carrier/
      - sophacles 14y ago
        From friends and family in the navy: whenever you see a fleet or battle group "stationed" somewhere, it means they are basically doing right turns in the middle of the ocean (a joke being that someone has to balance the effect of all those left turning NASCAR races). While they are doing operations etc, a lot of this time is considered extremely boring, more so than even long voyages going somewhere. Further, they usually aren't going full speed, so to some extent they are "just sitting there", particularly in the effect that they aren't using the full output of their power systems - leaving lots of power and (if needed people time) available for fuel "creation".
        dctoedt 14y ago
        Former Navy aircraft-carrier nuclear engineering officer here. The basic point --- that a carrier might be able to refine its own jet fuel --- is certainly valid. But so that future readers don't get the wrong idea: Any time a carrier is at sea, it does a lot of flight ops just about every day, whether for actual missions, for war games, or just refresher training. That in turn means most of the crew is hustling, usually 12 to 14 hours a day minimum, and sometimes 'round the clock. Maintenance has to be done in the gaps. When we were at sea, it was rare to get six hours of uninterrupted sleep in a night. Somehow I doubt that has changed.
jws 14y ago
Extract CO2 and H2 from seawater, react to form hydrocarbons of varying lengths, then refine. Presumably all powered by the nuclear reactors. initial studies predict that jet fuel from seawater would cost in the range of $3 to $6 per gallon to produce
- ChuckMcM 14y ago
  That is exactly why its such a big deal. Current jet fuel costs over $8/gal delivered. It costs so much because even if it comes out of the refinery at San Diego at $2/gal it has to be loaded into an oiler [1] and then driven out to sea where the carrier task group is. If you're on a nuclear powered aircraft carrier you have plenty of electricity so this is a pretty huge win. Of course an alternative way to make this feasible for the fleet would be to build a nuclear powered oiler. It could process seawater into jet fuel as it cruised along with the fleet and transfer fuel as needed, but to this day fuel transfer at sea is one of the more dangerous things they do. [1] http://en.wikipedia.org/wiki/Replenishment_oiler http://en.wikipedia.org/wiki/Replenishment_oiler
  - jnw2 14y ago
    http://en.wikipedia.org/wiki/USS_Gerald_R._Ford_(CVN-78) http://en.wikipedia.org/wiki/USS_Gerald_R._Ford_(CVN-78) notes that ``Unfortunately the power limitations for the Nimitz class make the installation of the recently developed [Electromagnetic Aircraft Launch System] impossible.'', which seems to indicate that existing nuclear powered aircraft carriers don't always have large amounts of electricity to spare. However, more electricity will be available on future aircraft carriers.
    - danmaz74 14y ago
      But the launch system has to work reliably at any moment, especially when the ship is in full operation at a time of crisis. On the other hand, this process could work at off-peak times, of which I think there is plenty on a carrier too.
    - ChuckMcM 14y ago
spullara 14y ago
When energy is cheap, plentiful and clean things like this are possible. If only we built more nuclear power plants and solar power farms. Turning coal into jet fuel isn't a great idea :)
- ryanwaggoner 14y ago
  Rejoice then, because this will almost certainly be done on carriers powered by nuclear power plants.
  - spullara 14y ago
    But of course! That was sort of my point...
    - ryanwaggoner 14y ago
      Duh...my bad. It's late :)
rdl 14y ago
One of the main endurance (and damage control) problems for a nuclear carrier is the huge amount of jet fuel used by the air wing, so this would be a huge deal. After jet fuel, they just need to underway replenish armaments and food, both of which are easier than fuel (food isn't dangerous, and most missions don't expend weapons now, so the total volume is lower than for fuel).
wamatt 14y ago
Very interesting. Can someone who knows about this stuff comment on whether the energy required to extract the H2 from the water, is more than the energy contained in the chemical bonds of the H2 itself? (assume both sides of the comparison contain equal number of molecules) I suspect it is.. otherwise they are potentially sitting on a much more important innovation, than mere jet fuel.
- jordanb 14y ago
  Consider it from the perspective of the conservation of energy: 2H2 + O2 = 2H2O + energy The energy is on the right because the reaction is exothermic. The opposite reaction must be endothermic and must have the same amount of energy on the left: 2H2O + energy = 2H2 + O2 Otherwise, energy isn't conserved. Because nothing is 100% efficient, there's also energy lost to inefficiencies. So the answer to your question is that yes, you need more energy to make the second reaction happen than is stored in the chemical bond.
deleted 14y ago
[deleted]
sien 14y ago
This is a good reason why Tesla cars are folly. This is why electric vehicles won't work. I'll copy in most of a comment I made a few days back. Let's say tomorrow some grad student gets fusion going at a very low price. The best way to use this to power cars would be to use it to create a fuel with a high energy density. If you had 'free energy' you'd extract C02 from the atmosphere and turn it into a hydrocarbon. For more info look at: http://en.wikipedia.org/wiki/Energy_density http://en.wikipedia.org/wiki/Energy_density and this interview with Nobel Prize winning Physicist Robert Laughlin http://www.econtalk.org/archives/2010/08/laughlin_on_the.htm.. http://www.econtalk.org/archives/2010/08/laughlin_on_the.htm.... the key quote is: "The ones that are technically trained get it right away: hydrocarbons, which we burned today have the greatest energy density possible of all fuels. Things that have carbon in them. Will people fly airplanes? Usually people say yes for the same reasons. Well, how are you going to make the airplanes fly? Battery. Batteries are pretty heavy. Oh--you can't have airplanes unless you have hydrocarbon fuels. You could in theory do it with hydrogen, but it's highly dangerous, noxious fuel. Quantum-mechanically, we know the energy content of those fuels is optimal. There will never be anything that beats them." A massive breakthrough in energy density for batteries might be possible but it's unlikely. Huge resources have been put into improving batteries and while they have improved it's not been enough to get near the energy density of hydrocarbons.
- Mvandenbergh 14y ago
  Most people miss the difference between hydrocarbon fuels as energy source* and as energy carrier. If you make HC fuels from atmospheric or oceanic carbon, you have a nice closed cycle. (*) Technically fossilised solar energy of course.
- ta12121 14y ago
  No. Electrolysing water to make H2 and extracting CO2 from the environment, and then synthesizing hydrocarbons from them, is extremely energy inefficient. Sure, theoretically, it can be done, and maybe one day it could even be done efficiently. But Tesla is making battery-electric cars that work today. The military does not care about efficiency because they have nuclear reactors on their ships and their goal is to not to have to transport liquid fuel.
bluestix 14y ago
R.I.P Stan Meyer
FrojoS 14y ago
Once again, military research might lead the way. Note, if they invest into this, it's _not_ because of reduced price, increased efficiency or reduced greenhouse effects, but because of an _strategic_ advantage against "the enemy". Personally, I read about similar methods, for synthesizing carbon based fuels, many times before. Most of them were private founded but rather small scale. I can't judge if there was a significant science or engineering breakthrough. So, I suspect the only thing that might have changed, is that a clever guy convinced the military this would be a huge strategic advantage. The ironic thing is, the US could instead focus on producing all their fuel at home to end the dependency on oil from the middle east. Then, they would have an even bigger strategic advantage and wouldn't need as much military investment. Anyway, we might end up with synthetic carbon based fuel with all its advantages - and probably the military can keep their carriers.
- 1rae 14y ago
  I think Sasol (SA) has this Gas-To-Liquid fuel system working, and on a larger commercial scale http://www.sasol.com/sasol_internet/frontend/navigation.jsp?navid=21300010&rootid=2 http://www.sasol.com/sasol_internet/frontend/navigation.jsp?...
Roritharr 14y ago
Isn't this also heavily destructive to our ecosystem because they use the carbon trapped in the water and release it into our atmosphere? Didn't we want more trapped carbon than less? I don't get why everyone finds this great since it takes a very long time for carbon in the atmosphere to get trapped in seawater.
- zmmz 14y ago
  It's not that simple: CO2 in atmosphere -> CO2 in water -> Ocean acidification[1] -> Change in ocean ecosystem The oceans absorb OC2 from the atmosphere, which you could argue is good, but it is not without consequences. Putting CO2 in the water moves the problem from having it in the atmosphere elsewhere, but it's still a problem. In some ways then, this can be seen as a good thing, because it is undoing the effects that increased CO2 in the atmosphere has on the oceans. Obviously though, I doubt that its effects would be at all noticeable. The wiki article already linked has a chapter called 'Possible Impact'. 1: http://en.wikipedia.org/wiki/Ocean_acidification http://en.wikipedia.org/wiki/Ocean_acidification
  - Roritharr 14y ago
    I'm not for putting more carbon into the oceans... just against taking the currently stored carbon out.
    - regularfry 14y ago
      There is already too much. Any we can take out is a good thing.
      - xefer 14y ago
        But it's taking carbon out of the ocean and releasing it into the atmosphere. The issue becomes, how long does it take for the released atmospheric CO2 to be reabeorbed back into he ocean? Does it do more harm in the atmosphere or in the ocean?
jimworm 14y ago
France could certainly use this technology. With their abundance of unused nuclear power and access to the sea, this could bridge the gap between hydrocarbon powered and electric vehicles.

72 points by joe24pack 14y ago

gunn 14y ago

Okay great. Where does the energy come from?

landryraccoon 14y ago
If it's an aircraft carrier, probably the nuclear power plant on board.
- pixie_ 14y ago
  Yep, it's a pretty good use of 200MW of power when you're just sitting around in the ocean.
  - dctoedt 14y ago
    > when you're just sitting around in the ocean Watch any of the documentary series about life aboard an aircraft carrier [1] and you'll see that there's essentially no "just sitting around in the ocean." But your main point is still accurate: If there's power available, putting it to work making jet fuel might be a good trade-off for the additional drain on the nuclear fuel. [1] E.g., http://www.pbs.org/weta/carrier/ http://www.pbs.org/weta/carrier/
    - sophacles 14y ago
      From friends and family in the navy: whenever you see a fleet or battle group "stationed" somewhere, it means they are basically doing right turns in the middle of the ocean (a joke being that someone has to balance the effect of all those left turning NASCAR races). While they are doing operations etc, a lot of this time is considered extremely boring, more so than even long voyages going somewhere. Further, they usually aren't going full speed, so to some extent they are "just sitting there", particularly in the effect that they aren't using the full output of their power systems - leaving lots of power and (if needed people time) available for fuel "creation".
      - dctoedt 14y ago
        Former Navy aircraft-carrier nuclear engineering officer here. The basic point --- that a carrier might be able to refine its own jet fuel --- is certainly valid. But so that future readers don't get the wrong idea: Any time a carrier is at sea, it does a lot of flight ops just about every day, whether for actual missions, for war games, or just refresher training. That in turn means most of the crew is hustling, usually 12 to 14 hours a day minimum, and sometimes 'round the clock. Maintenance has to be done in the gaps. When we were at sea, it was rare to get six hours of uninterrupted sleep in a night. Somehow I doubt that has changed.

jws 14y ago

Extract CO2 and H2 from seawater, react to form hydrocarbons of varying lengths, then refine. Presumably all powered by the nuclear reactors. initial studies predict that jet fuel from seawater would cost in the range of $3 to $6 per gallon to produce

ChuckMcM 14y ago
That is exactly why its such a big deal. Current jet fuel costs over $8/gal delivered. It costs so much because even if it comes out of the refinery at San Diego at $2/gal it has to be loaded into an oiler [1] and then driven out to sea where the carrier task group is. If you're on a nuclear powered aircraft carrier you have plenty of electricity so this is a pretty huge win. Of course an alternative way to make this feasible for the fleet would be to build a nuclear powered oiler. It could process seawater into jet fuel as it cruised along with the fleet and transfer fuel as needed, but to this day fuel transfer at sea is one of the more dangerous things they do. [1] http://en.wikipedia.org/wiki/Replenishment_oiler http://en.wikipedia.org/wiki/Replenishment_oiler
- jnw2 14y ago
  http://en.wikipedia.org/wiki/USS_Gerald_R._Ford_(CVN-78) http://en.wikipedia.org/wiki/USS_Gerald_R._Ford_(CVN-78) notes that ``Unfortunately the power limitations for the Nimitz class make the installation of the recently developed [Electromagnetic Aircraft Launch System] impossible.'', which seems to indicate that existing nuclear powered aircraft carriers don't always have large amounts of electricity to spare. However, more electricity will be available on future aircraft carriers.
  - danmaz74 14y ago
    But the launch system has to work reliably at any moment, especially when the ship is in full operation at a time of crisis. On the other hand, this process could work at off-peak times, of which I think there is plenty on a carrier too.
  - ChuckMcM 14y ago

spullara 14y ago

When energy is cheap, plentiful and clean things like this are possible. If only we built more nuclear power plants and solar power farms. Turning coal into jet fuel isn't a great idea :)

ryanwaggoner 14y ago
Rejoice then, because this will almost certainly be done on carriers powered by nuclear power plants.
- spullara 14y ago
  But of course! That was sort of my point...
  - ryanwaggoner 14y ago
    Duh...my bad. It's late :)

rdl 14y ago

One of the main endurance (and damage control) problems for a nuclear carrier is the huge amount of jet fuel used by the air wing, so this would be a huge deal. After jet fuel, they just need to underway replenish armaments and food, both of which are easier than fuel (food isn't dangerous, and most missions don't expend weapons now, so the total volume is lower than for fuel).

wamatt 14y ago

Very interesting. Can someone who knows about this stuff comment on whether the energy required to extract the H2 from the water, is more than the energy contained in the chemical bonds of the H2 itself? (assume both sides of the comparison contain equal number of molecules) I suspect it is.. otherwise they are potentially sitting on a much more important innovation, than mere jet fuel.

jordanb 14y ago
Consider it from the perspective of the conservation of energy: 2H2 + O2 = 2H2O + energy The energy is on the right because the reaction is exothermic. The opposite reaction must be endothermic and must have the same amount of energy on the left: 2H2O + energy = 2H2 + O2 Otherwise, energy isn't conserved. Because nothing is 100% efficient, there's also energy lost to inefficiencies. So the answer to your question is that yes, you need more energy to make the second reaction happen than is stored in the chemical bond.

deleted 14y ago

[deleted]

sien 14y ago

This is a good reason why Tesla cars are folly. This is why electric vehicles won't work. I'll copy in most of a comment I made a few days back. Let's say tomorrow some grad student gets fusion going at a very low price. The best way to use this to power cars would be to use it to create a fuel with a high energy density. If you had 'free energy' you'd extract C02 from the atmosphere and turn it into a hydrocarbon. For more info look at: http://en.wikipedia.org/wiki/Energy_density http://en.wikipedia.org/wiki/Energy_density and this interview with Nobel Prize winning Physicist Robert Laughlin http://www.econtalk.org/archives/2010/08/laughlin_on_the.htm.. http://www.econtalk.org/archives/2010/08/laughlin_on_the.htm.... the key quote is: "The ones that are technically trained get it right away: hydrocarbons, which we burned today have the greatest energy density possible of all fuels. Things that have carbon in them. Will people fly airplanes? Usually people say yes for the same reasons. Well, how are you going to make the airplanes fly? Battery. Batteries are pretty heavy. Oh--you can't have airplanes unless you have hydrocarbon fuels. You could in theory do it with hydrogen, but it's highly dangerous, noxious fuel. Quantum-mechanically, we know the energy content of those fuels is optimal. There will never be anything that beats them." A massive breakthrough in energy density for batteries might be possible but it's unlikely. Huge resources have been put into improving batteries and while they have improved it's not been enough to get near the energy density of hydrocarbons.

Mvandenbergh 14y ago
Most people miss the difference between hydrocarbon fuels as energy source* and as energy carrier. If you make HC fuels from atmospheric or oceanic carbon, you have a nice closed cycle. (*) Technically fossilised solar energy of course.
ta12121 14y ago
No. Electrolysing water to make H2 and extracting CO2 from the environment, and then synthesizing hydrocarbons from them, is extremely energy inefficient. Sure, theoretically, it can be done, and maybe one day it could even be done efficiently. But Tesla is making battery-electric cars that work today. The military does not care about efficiency because they have nuclear reactors on their ships and their goal is to not to have to transport liquid fuel.

bluestix 14y ago

R.I.P Stan Meyer

FrojoS 14y ago

Once again, military research might lead the way. Note, if they invest into this, it's _not_ because of reduced price, increased efficiency or reduced greenhouse effects, but because of an _strategic_ advantage against "the enemy". Personally, I read about similar methods, for synthesizing carbon based fuels, many times before. Most of them were private founded but rather small scale. I can't judge if there was a significant science or engineering breakthrough. So, I suspect the only thing that might have changed, is that a clever guy convinced the military this would be a huge strategic advantage. The ironic thing is, the US could instead focus on producing all their fuel at home to end the dependency on oil from the middle east. Then, they would have an even bigger strategic advantage and wouldn't need as much military investment. Anyway, we might end up with synthetic carbon based fuel with all its advantages - and probably the military can keep their carriers.

1rae 14y ago
I think Sasol (SA) has this Gas-To-Liquid fuel system working, and on a larger commercial scale http://www.sasol.com/sasol_internet/frontend/navigation.jsp?navid=21300010&rootid=2 http://www.sasol.com/sasol_internet/frontend/navigation.jsp?...

Roritharr 14y ago

Isn't this also heavily destructive to our ecosystem because they use the carbon trapped in the water and release it into our atmosphere? Didn't we want more trapped carbon than less? I don't get why everyone finds this great since it takes a very long time for carbon in the atmosphere to get trapped in seawater.

zmmz 14y ago
It's not that simple: CO2 in atmosphere -> CO2 in water -> Ocean acidification[1] -> Change in ocean ecosystem The oceans absorb OC2 from the atmosphere, which you could argue is good, but it is not without consequences. Putting CO2 in the water moves the problem from having it in the atmosphere elsewhere, but it's still a problem. In some ways then, this can be seen as a good thing, because it is undoing the effects that increased CO2 in the atmosphere has on the oceans. Obviously though, I doubt that its effects would be at all noticeable. The wiki article already linked has a chapter called 'Possible Impact'. 1: http://en.wikipedia.org/wiki/Ocean_acidification http://en.wikipedia.org/wiki/Ocean_acidification
- Roritharr 14y ago
  I'm not for putting more carbon into the oceans... just against taking the currently stored carbon out.
  - regularfry 14y ago
    There is already too much. Any we can take out is a good thing.
    - xefer 14y ago
      But it's taking carbon out of the ocean and releasing it into the atmosphere. The issue becomes, how long does it take for the released atmospheric CO2 to be reabeorbed back into he ocean? Does it do more harm in the atmosphere or in the ocean?

jimworm 14y ago

France could certainly use this technology. With their abundance of unused nuclear power and access to the sea, this could bridge the gap between hydrocarbon powered and electric vehicles.