Burning seawater..

[Gubbi]

If, assuming that amount of energy to break apart the salt water is less than energy that comes out of the fuel cell, then its a win,

Which is isn't.

You use radiowaves to break up water:
1. H2O -> H2 + O
Then use a fuel cell to recombine it.
2. H2+O -> H2O

End result is a lot of energy wasted.

Cheers

 

[soylent]

You're obviously assuming step 1 is where the energy of the system is coming from, and steps 2, 3 are simply drags on the system.

And you are assuming otherwise?

If, assuming that amount of energy to break apart the salt water is less than energy that comes out of the fuel cell, then its a win...

I'd like to assume that the first rule of thermodynamics is true until proven otherwise.

 

[weaksauce]

What's the salt for and what's the difference between that and this?
http://youtube.com/watch?v=pXo7CVFI5Sk

Different flame obviously.

 

[RussSchultz]

And you are assuming otherwise?

I'd like to assume that the first rule of thermodynamics is true until proven otherwise.

Why would the first rule of thermodynamics be broken?

How do we get more energy out of gasoline than the spark to ignite it?

Its because the energy was put 'into' the system from the outside (i.e. the energy to form the gasoline isn't part of the system).

I'm assuming that something about the salt and/or radio waves acts as a catalyst that lowers the energy of activation/splitting of the water into H and O, not simply that the energy put in to split is apart is regained when it goes through the fuel cell or combustion. Otherwise, you're right, completely uninteresting.

 

[3dilettante]

I don't know about the utility of this, given the data available.

It's not the first time someone's microwaved salt water.
It's not the first time someone's bounced radio waves off of seawater.

It seems plausible a flame could be generated with enough energy put in, but I'd expect that if it were to lead to a useful combustion reaction, the eureka moment should have happened decades ago.

 

[Mintmaster]

How do we get more energy out of gasoline than the spark to ignite it?

Its because the energy was put 'into' the system from the outside (i.e. the energy to form the gasoline isn't part of the system).

Right. The sun's energy created the gasoline millions of years ago. So in your system, where does the energy to form the H2 come from? Black magic?

I'm assuming that something about the salt and/or radio waves acts as a catalyst that lowers the energy of activation/splitting of the water into H and O, not simply that the energy put in to split is apart is regained when it goes through the fuel cell or combustion. Otherwise, you're right, completely uninteresting.

Russ, do you know what a catalyst is?

You don't change the energy balance of a reaction. All you do is change the kinetics. For combustion, a catalyst is useless. A flame, by definition, is self sustaining, i.e. the energy from a unit of fuel is enough to overcome the activation energy from the next unit. Activation energy, however, has nothing to do with the energy released. Only the enthalpy of the reaction matters there.

You can't split water into H2 and O2 with less energy than you get from recombining them when burning hydrogen. That you thought otherwise is absolutely shocking to me, as you always came across to me as reasonably informed about science. I almost thought someone else is posting under your account.

 

[RussSchultz]

Russ, do you know what a catalyst is?

Yes, its something that lowers the activation energy.

You don't change the energy balance of a reaction. All you do is change the kinetics.

I never said it did.

You can't split water into H2 and O2 with less energy than you get from recombining them when burning hydrogen. That you thought otherwise is absolutely shocking to me, as you always came across to me as reasonably informed about science. I almost thought someone else is posting under your account.

I'm not a chemist, so forgive me for deferring to the chemist/phsycists in the piece. I'm assuming there's something they're interested in with respect to energy generation. A novel way to achieve electrolosis really isn't all that interesting..

And, for the record, I never assumed in a closed system that energy could be obtained from chemical reactions. I assume that something was consumed in the process. Just like the 'aluminum slurry' catalyst that was discussed a few weeks/months that split water, that particular reaction was energy positive. The whole cycle obviously isn't, as de-oxydizing the aluminum was energy intensive, making this, in my opinion, a transport mechanism/battery more than a "free energy" concept.

 

[doob]

I might be saying the dumbest thing on this thread so far, but lets consider the most efficient microwave possible, how much cubic meters(or less than) of salt water would it be able to ignite? Wouldn't that increase the output of energy released?

 

[3dilettante]

The way it would most likely work is exposing the surface of the brine to an external transmitter.

At a given instant, it would be best described as burning a given area of water surface, which is closer to an area problem than a volume one.
This would bring up two different dimensions of diminishing returns for increasing the amount of brine processed.

More brine is likely to increase volume faster than surface area exposed, which means more energy is needed to move more water and radiate it. This unfortunately puts a cap on the rate of burning, as water won't burn until near the surface.

This can be handled if the water is spread out, but the wider area would require the transmitter be either further away (inverse square) or more of them would be needed (quadratic increase in the amount of area to be covered).

The description is lacking, but that's how I'd see an accidental discovery happening like this.

 

[soylent]

Why would the first rule of thermodynamics be broken?

How do we get more energy out of gasoline than the spark to ignite it?

The molecules in gasoline and the oxygen required to burn it have a bonding energy higher than that of the reaction products. It's in a potential well so we need to supply enough heat for the reaction to start occuring; when it has started it is self-sustaining because the reaction is strongly exothermic.

That's not the case here. They are essentially bringing along the exhaust and combining it with some salt(the 'ash' from burning free sodium and chlorine all those billions of years ago...) and constructing the fuel on the fly using batteries.

The salt is unchanged and the water goes to hydrogen gas + oxygen gas and back into water. There's no internal energy you can tap into, all the energy you get out is energy you have put in. For it to be of any use you have to get more out than you put in, if that's the case you can just close the loop and build a perpetual motion generator.

Its because the energy was put 'into' the system from the outside (i.e. the energy to form the gasoline isn't part of the system).

Right, by photosynthesis all those millions of years ago when the oceans where in an anoxic state. That's not the case here; you're not extracting energy from the salt water because there's no storage mechanism. The products of the reaction are the same as the reactants.

I'm assuming that something about the salt and/or radio waves acts as a catalyst that lowers the energy of activation/splitting of the water into H and O, not simply that the energy put in to split is apart is regained when it goes through the fuel cell or combustion. Otherwise, you're right, completely uninteresting.

A catalyst lowers the excess(activation energy) energy you have to put in to make the reaction occur at feasible rates. Molecules are stable because they are in a potential well; if you twist them and turn them or start trying to pulling atoms off you increase its internal energy. There's an intermediate state in a reaction that costs more energy than either the reactants or products.

 

[Mintmaster]

Yes, its something that lowers the activation energy.

Well then do you know what activation energy is? It has nothing to do with the energy consumed.

And, for the record, I never assumed in a closed system that energy could be obtained from chemical reactions. I assume that something was consumed in the process. Just like the 'aluminum slurry' catalyst that was discussed a few weeks/months that split water, that particular reaction was energy positive. The whole cycle obviously isn't, as de-oxydizing the aluminum was energy intensive, making this, in my opinion, a transport mechanism/battery more than a "free energy" concept.

In the aluminum piece, aluminum was not a catalyst. It's the fuel. You start with aluminum and water, then end up with aluminum oxide and water. The aluminum is transporting the energy.

Here, you are starting with water and end up with water. There is no energy transport mechanism here and that's what I'm trying to tell you. It's just another way to create hydrogen (and for that process salt may indeed be a catalyst), except the hydrogen is burned immediately after you create it so it's rather useless at the moment. Maybe it could one day replace electrolysis, but we still need a way to store the hydrogen efficiently.

 

[DemoCoder]

I just skimmed this thread, is there any information that shows that this is anything other than a less efficient electrolysis method? If it were more efficient than regular electrolysis, I'd be surprised, but if the salt is really acting to increase the efficiency, then I wonder if the same would apply to tradition electrolysis.

In other words, any efficiency comparisons should take apples-to-oranges and apples-to-apples into comparison.

 

[nelg]

I wonder if the magnesium content of seawater might play a role. Similar to the method in the other thread about using aluminum as a catalyst to break apart water. If the the magnesium chloride in sea water can be broken apart, the unbound mag may be able to react with the water.

I think that, even though there is no net energy produced, ideas such as this may prove very useful as storage mediums. Allowing for higher utilization of existing hydro generation.

 

[soylent]

I think that, even though there is no net energy produced, ideas such as this may prove very useful as storage mediums. Allowing for higher utilization of existing hydro generation.

He isn't storing any energy in sea water.

 

[Mintmaster]

I wonder if the magnesium content of seawater might play a role. Similar to the method in the other thread about using aluminum as a catalyst to break apart water. If the the magnesium chloride in sea water can be broken apart, the unbound mag may be able to react with the water.

A) In the other thread, aluminum was a fuel, not a catalyst. Solid aluminum reacted to become aluminum oxide. Hydrogen is the means of getting that energy into the engine.
B) Magnesium chloride already is broken up into ions. It's in a lower energy state than solid magnesium chloride, which in turn is probably in a lower energy state than magnesium oxide (i.e. you'd get more energy out reacting solid Mg with Cl2 than with O2).

I think that, even though there is no net energy produced, ideas such as this may prove very useful as storage mediums. Allowing for higher utilization of existing hydro generation.

As soylent said, there is no storage here. Unless, of course, you capture the hydrogen, but using hydrogen as an energy storage medium isn't exactly groundbreaking.

The aluminum idea, OTOH, is indeed a new storage mechanism.

 

[Bigus Dickus]

Flash from the past! I went through this same line of thought in 6th grade. Of course, I didn't know about the new nifty electrolysis method this guy may have discovered, but that seems irrelevant.

I was all excited back then when I learned that electricity could split water into hydrogen and oxygen, and that you could combine and ignite the hydrogen and oxygen to power an internal combustion engine! Until I did some research at the public library and learned that the energy required to split water into H2 and O is greater than that released from combusting H2 and O.

Sigh. I guess this guy skipped 6th grade.

 

[ninelven]

Sigh. I guess this guy skipped 6th grade.

"Why does everyone think this is a form of electrolysis?"
"He says that the process would not be considered a form of electrolysis."

.
.
.

...do people even read anymore?

 

[soylent]

"Why does everyone think this is a form of electrolysis?"
"He says that the process would not be considered a form of electrolysis."

.
.
.

...do people even read anymore?

I know, it's too generous; in electrolysis you get to keep the hydrogen without burning it immediately.