Wednesday, September 12, 2007

Burning Salt Water

A friend sent me this article. John Kanzius accidentally discovered he could make salt water burn by subjecting it to radio waves.

This does not seem like a hoax. It's reported by reliable news sources. Kanzius is a scientist and seems to have been careful in his approach. He had it independently checked by a chemist. Of course, I want to believe it because it is very cool.

You can do the same thing with pure water by running an electric current through water. We did it in high school chemistry. The electric current breaks water (no salt needed) into hydrogen and oxygen. The problem is that it takes more electric energy to break apart the water than the energy you get from the combustion.

Radio waves are electromagnetic fields. It makes sense that they could affect the bonds of water in a similar way to passing a current through the water. I would think the frequency matters. If so, Kanzius was very lucky.

So I'm pretty sure Kanzius came up with something. It is at least a very neat chemistry demonstration. Is it anything more? Can it solve the energy crisis?

The key question: how much energy is being put in by the radio frequency generator? Is the energy output significantly greater than the input? Kanzius' system needs to output significantly more energy than input for it to work. The articles I found don't mention how much energy is put into the system and how much comes out. Those measurements are critical.

Burning water and hydrogen is very clean and efficient. The by-product is water! I'm not sure if the sodium and chlorine are also getting burned -- they might produce something nasty.

Uh oh... now I feel like this is perpetual motion. Let me explain.

A non-perpetual motion reaction consumes the fuel. Gasoline is used in most car engines. Gasoline combines with oxygen when burned. The gasoline is made up of hydrogen and carbon atoms. When it burns they combine with oxygen and produce things like water, carbon, carbon-monoxide and carbon-dioxide. The gasoline is gone. The reaction is not circular. Energy came out, but the fuel was consumed. You need more fuel to keep going. I can't be precise about the reaction because I don't know enough about gasoline chemistry but the idea is: Gasoline + Oxygen + EnergyIn ==> Water + Carbon + Carbon-monoxide + Carbon-dioxide + OtherStuff - EnergyOut (EnergyIn is the ignition spark and EnergyOut is the heat from burning).

In Kanzius' system I think the reaction looks like this: Water + EnergyIn ==> Hydrogen + Oxygen + EnergyIn2 ==> Water - EnergyOut (EnergyIn is energy in from radio waves, EnergyIn2 is the spark to light the fire and EnergyOut is heat from burning). For this to work as a power source EnergyOut must be greater than EnergyIn and EnergyIn2. That means there is some left over energy = EnergyOut - EnergyIn - EnergyIn2 = EnergyNet. EnergyNet can be taken out of the system which is what makes this useful. So far, so good, just like gasoline. However, the resulting product is water. The reaction does not consume the fuel. That is a perpetual motion machine, which is not possible. The laws of thermodynamics state that any process like this must lose energy.

Kanzius' system requires more than water. It also requires salt. The salt molecule is made up of sodium and chlorine, which is why it is called sodium chloride. Do the sodium and chlorine somehow change the reaction so it is not circular? Is the salt consumed? Do sodium and chlorine interact with the oxygen and hydrogen to produce something else and avoid the water product? It's been a long time since I've had chemistry. Any ideas?

Say Kanzius' system actually does produce significant energy. There are still other questions.
  1. Does the salt produce nasty by-products when burned?
  2. How cheap is the radio frequency generator?
  3. Can the system be usefully packaged?
  4. The external combustion Stirling engine (which a Kanzius system powered) is not very efficient cost or weight-wise. It is not very good for vehicles like cars. Is there another way to harness Kanzius energy?
  5. Can salt water be used for internal combustion and thus be more suitable for cars? Salt water is very corrosive which could cause all sorts of maintenance issues. It also could be very difficult to set up proper radio frequency generators in internal combustion engines.
I hope this turns out well, but there is reason for skepticism. The easiest answer will be that despite the obvious high temperature and energy of the burning the input energy is actually greater than the output energy when all is properly measured.

A final thought occurs to me. If it is the salt that is consumed, conceivably you could conserve the water and just keep adding salt. This means the real fuel would be salt, not salt water. You would also get a nifty desalinization process, which is what Kanzius was going for in the first place. This would make it a great way to to propel a ship. Your engine uses sea water for fuel and outputs the fresh water you need to survive. A ship, by the way, is big enough to possibly use a Stirling engine effectively.

1 comment:

Don the Baptist said...

Thanks for the exposition of the various aspects. Clear and concise.