Sea water and AC-current?

[BigJackW]

Hi

 

I'm working as an electrician doing installation on ships etc. When we're testing generators we use a thub with sea water in it and 3 copper tubes connected to the three-phase 230v system. We're gradually lowering the tubes into the water which results in a increase of current flowing. No problem to pull 300++ amps.

 

My question is, are there any chemical reaction happening when applying 3phase AC current to sea water like that, or will the water just boil?

[EratosthenesII]

FWIW electrolysis uses low volts DC so my guess is a lot more steam generated than hydrogen. Al smelter uses 3-5volts DC

[studiot]

As an electrician you need to be aware of 'electrode boilers', which are often three phase.

 

 

Google is your friend.

There's lots there.

[Enthalpy]

I did similar things and got mainly vapour. But, yes, chemical reactions happen. One would have expected a production of hydrogen and chlorine, but even with DC they readily combine and produce sodium hypochlorite - this will happen even more with AC.

 

Beware hypochlorite - the very one used in household - is a poison. It's the one poison that kills most people in Europe. But when you smell it you have still time to vent the room.

 

In addition, electrodes react heavily with evolving gas, because they ions and single atoms right in contact with the electrodes are very corrosive. You normally get some little soluble copper compound in the liquid after some time, green or blue depending on luck. Electrodes that resist these conditions are difficult to choose, with graphite being more affordable than precious metals like platinum.