Fuel from seawater?

[freakazoid]

sorry, but the use of a natural resource does not constitute free.

... I think it kind of does.

[geronimotwo]

... I think it kind of does.

every form of energy we have today uses something else to create it, therefore it is not free.  i would include solar with this, even aside from the manufacturing of the panels, as photons are required to free electrons in the sillicon chips.  evidently, my definition of free is more strict than others here.  i can live with that. 

to elaborate on my water comment earlier.   water is the most precious resource that we have.  without it all life on this planet would cease to exist, as we know it.  arguing that we can harvest it from other parts of the solar system does not change that it is, aside from an intersteller comet, a finite supply within our reach.  converting water to use the hydrogen for energy may not release dangerous chemicals, but it does use the water itself, which leads to the remaining water having a higher concentration of not only minerals but pollutants as well.  when water has a higher concentration of minerals it changes the cycle of the evaporation process, which may or may not effect weather patterns and the availability of fresh water.   certainly one can argue that we would use such a small amount of water that it wouldn't have an immediate impact on life as we know it.  i might agree with that where one or twenty naval ships are concerned, but we also have to wiegh the importance of water itself before we make decisions that will irrevocably change the future of our planet.  i'm not concerned about the next 5 or even 50 years, i would hope that we can plan for the next 50,000 (assuming that we haven't made other foolish decisions along the way).  certainly all of the previous concerns are speculation on my part, but water is our future.  don't mess with it!

[birdman]

every form of energy we have today uses something else to create it, therefore it is not free.  i would include solar with this, even aside from the manufacturing of the panels, as photons are required to free electrons in the sillicon chips.  evidently, my definition of free is more strict than others here.  i can live with that. 

to elaborate on my water comment earlier.   water is the most precious resource that we have.  without it all life on this planet would cease to exist, as we know it.  arguing that we can harvest it from other parts of the solar system does not change that it is, aside from an intersteller comet, a finite supply within our reach.  converting water to use the hydrogen for energy may not release dangerous chemicals, but it does use the water itself, which leads to the remaining water having a higher concentration of not only minerals but pollutants as well.  when water has a higher concentration of minerals it changes the cycle of the evaporation process, which may or may not effect weather patterns and the availability of fresh water.   certainly one can argue that we would use such a small amount of water that it wouldn't have an immediate impact on life as we know it.  i might agree with that where one or twenty naval ships are concerned, but we also have to wiegh the importance of water itself before we make decisions that will irrevocably change the future of our planet.  i'm not concerned about the next 5 or even 50 years, i would hope that we can plan for the next 50,000 (assuming that we haven't made other foolish decisions along the way).  certainly all of the previous concerns are speculation on my part, but water is our future.  don't mess with it!

No, it really doesn't.
Burning the hydrogen creates exactly the same a mount of water that was used to make the hydrogen.
As for increasing mineral content, even if the world did this for ALL of its energy needs, AND we used 100x as much energy it would make less than a 1% difference in the amount of water vapor created every day! less than a 0.1% difference in total atmospheric water vapor content! and less than a 0.0000001% difference in the relative concentration of minerals and other dissolved materials in water.

[geronimotwo]

i guess my knowledge of this stuff is limited.  how is it that we can separate and burn hydrogen from molecules that created the water, and still end up with the same amount of water?   for example, if we have 100 molecules of h2o, that would lead me to believe that there are 200 hydrogen atoms, and 100 oxygen atoms.   next we break up these molecules and use half of the hydrogen to create energy.  yes, the other half mayl combine with the oxygen that's left and create water, but how can we say it makes the same amount of water? 

[dogmush]

Burning is called "oxidizing" for a reason. We use all 200 H atoms for energy. And when we burn them they recombine with oxygen to go back to H2O.

Think of the hydrogen as a fancy battery. We add energy to get the liquid hydro carbon. When we extract the energy it reverts back to H2O.  The shall chemistry is more complicated, but that's roughly it.

[Tallpine]

i guess my knowledge of this stuff is limited.  how is it that we can separate and burn hydrogen from molecules that created the water, and still end up with the same amount of water?   for example, if we have 100 molecules of h2o, that would lead me to believe that there are 200 hydrogen atoms, and 100 oxygen atoms.   next we break up these molecules and use half of the hydrogen to create energy.  yes, the other half mayl combine with the oxygen that's left and create water, but how can we say it makes the same amount of water? 

You ever notice the water dripping out of your tail pipe before it gets hot enough to all turn to vapor 

[RoadKingLarry]

You ever notice the water dripping out of your tail pipe before it gets hot enough to all turn to vapor 

Chemtrails...

[230RN]

use half of the hydrogen to create energy

By burning it.  Which means recombining it with oxygen.  Which creates water again.  2H2 + O2 ---> 2H2O +heat and light.

The deficit comes in splitting the hydrogen off from the oxygen in the first place.  It takes a lot of energy to do that  --which comes from burning oil/coal/gas, nuclear fission, wind and water turbines photovoltaic cells, whatever.

[Scout26]

What birdman said.  (If the numbers are even that large, I would bet on much, much smaller)

Keep in mind that every living creature derives it's ability to sustain life by ingesting a variety of chemicals (including water), breaking and changing the chemical bonds to release that energy to stay alive.  We convert O2 to CO2, H20 into H4N2CO and C4H7N3O and also create many other "waste" products.

G2,

Your worry about water would be the same as saying we should stop breathing because we'll use up all the O2 in the atmosphere.    There's a constant cycle of nature, and living beings, breaking and creating molecular bonds; so that "running out", of something as ubiquitous as water is simply impossible.

[geronimotwo]

By burning it.  Which means recombining it with oxygen.  Which creates water again.  2H2 + O2 ---> 2H2O +heat and light.

The deficit comes in splitting the hydrogen off from the oxygen in the first place.  It takes a lot of energy to do that  --which comes from burning oil/coal/gas, nuclear fission, wind and water turbines photovoltaic cells, whatever.

i understand that part, but why is no one acknowledging that for there to be an energy output portions of the h2o are consumed?  and depending on the output, i am guessing a larger portion than what recombines to make water in the end.  much like the few drips of water coming out of the tailpipe, bur much larger portions of fuel are being used.   are there any charts available showing water-in vs water-out on this tech?

[birdman]

i understand that part, but why is no one acknowledging that for there to be an energy output portions of the h2o are consumed?  and depending on the output, i am guessing a larger portion than what recombines to make water in the end.  much like the few drips of water coming out of the tailpipe, bur much larger portions of fuel are being used.   are there any charts available showing water-in vs water-out on this tech?

None of the h2o is consumed.  Its conservation of mass.
-technically- a water molecule has a less mass than its constituent atoms, (like 1/1,000,000,000th), due to E=mc2,
But that isn't your point.
Your point is however incorrect, the number of hydrogen and oxygen atoms stays the same, we just re-arrange them.
Creating hydrogen from water:
2h2o + energy = 2h2 + 1 o2 (4 hydrogen and 2 oxygen on both sides of the equation)
Burning hydrogen
2h2 + o2 = 2h2o + energy (same 4 hydrogen and 2 oxygen on oth sides)
Note its the same in and out.

Burning is called "oxidizing" for a reason. We use all 200 H atoms for energy. And when we burn them they recombine with oxygen to go back to H2O.

Think of the hydrogen as a fancy battery. We add energy to get the liquid hydro carbon. When we extract the energy it reverts back to H2O.  The shall chemistry is more complicated, but that's roughly it.

Precisely.

[geronimotwo]

 my limited understanding of physics/chemistry isn't helping me to grasp how energy is produced without the consumption/changing of mass.      

so what form does the energy take?  is it heat that we use to produce steam and run an electric turbine?  is it an internal combustion engine?  does it directly release electrons to be used for consumption?

[freakazoid]

If you don't lose any then couldn't you run forever with just a pinch of water, it would be constantly recycling itself?

[Tallpine]

my limited understanding of physics/chemistry isn't helping me to grasp how energy is produced without the consumption/changing of mass.      

so what form does the energy take?  is it heat that we use to produce steam and run an electric turbine?  is it an internal combustion engine?  does it directly release electrons to be used for consumption?

It takes energy to decompose (electrolysis, usually) water into H and O.  Recombining them releases energy and yields water as "waste".

This is what used to be called 5th grade science.

[birdman]

so what form does the energy take?  is it heat that we use to produce steam and run an electric turbine?  is it an internal combustion engine?  does it directly release electrons to be used for consumption?

All of the above.
Heat produced for steam in a boiler, heat causing an increase in pressure which does work in an internal combustion engine, electrons driven across a potential difference in a fuel cell.

If you don't lose any then couldn't you run forever with just a pinch of water, it would be constantly recycling itself?

Well, you put energy in to crack the water, then get energy out when you recombine it.
So think of it like a battery analogy--you charge it by separating the water (and storing the hydrogen and oxygen), then you discharge it by recombining them, getting energy out.
You can't run forever because each process isn't 100% efficient.

[drewtam]

@G

It seems you are getting tripped up on conservation of mass
http://www.iun.edu/~cpanhd/C101webnotes/matter-and-energy/masscons.html

vs conservation of energy.
http://en.wikipedia.org/wiki/Conservation_of_energy


Imagine this flow chart:
Energy in = 100 units. [The energy comes from nuclear fission's heat].
Mass in  = 100 H2O

Energy out = 80 units waste heat + 20 units chemical energy
Mass out = 100 H2 + 50 O2

Notice 'mass in' equals 'mass out'.
'Energy in' equals 'energy out'. But 20 units of energy are now hidden / stored in the more volatile H2 & O2 gases. The other 80 units of waste heat are rejected to the atmosphere.


The volatile fuel is now transported to the gas station, and the car's fuel tank.
The car engine takes in 50 O2 & 100 H2. [Remember, this is still worth 20 units of energy stored up.]
Energy in  = 20 units
Mass in = 100 H2 + 50 O2

Energy out = 15 units waste heat + 5 units mechanical energy (running the car)
Mass out = 100 H2O

Notice 'mass in' equals 'mass out'.
'Energy in' equals 'energy out'.

The volatile H2 & O2 gases are now reduced to the very same amount of H2O again, which cycles back through the planet. The chemistry carried energy from the nuclear reactor to the cars wheels. Its like a truck carrying cargo inside, it consumes energy but the truck itself doesn't get changed. Of the 100 units of energy that the nuclear reactor produced, only 5 units made it to the car wheels, the other 95 is waste. No perpetual motion machines. It takes continually needing more nuke fuel to keep the energy process going. But the energy transportation system is not degraded at all. Water in equals water out.

[RevDisk]

The synfuel process doesn't create pure water, if you balance out all those equations, its a net input of water (which then is output when you burn the fuel).
Also, don't get the co2 from the air, get it from the water, where its more concentrated, and easier to extract (very easy in fact).  The whole point of the OP idea was it does the hydrogen plus CO2 part in situ using the dissolved CO2. 
Thus, water in, synfuel and surplus oxygen out.

Also, most desalination isn't distillation (re: your "chill it down" comment), its reverse osmosis, as that is far more economical from an energy basis.

Didn't know that about co2 and seawater. I have friends that work for Air Products, and they get a large amount of their atmospheric industrial gasses from fractional distillation of liquid air. I'm fuzzy on the engineering specifics, however. Industrial bulk chemical engineering processes is admittedly not one of specialties.

Chill it down was a guess that the hydrogen might be stored/processed in liquid form. Again, hazy on either liquid or merely compressed would be a more practical form. I do know from personal experience that hydrogen is a slippery bugger.