Half a croissant, on a plate, with a sign in front of it saying '50c'
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Bubble power induced electrolysis

Electrolysis powered by sea current and gas bubbling
  [vote for,

This idea is NOT about perpetual motion or anything of the sort.

Pipe inserted in sea in a horizontal diagonal position, so: /

Seawater enters the bottom. Turns a turbine in the middle.

The turbine serves as a dynamo or powers an electric generator.

As the water passes through the turbine, it generates electricity sent to two electrodes causing electrolysis.

Bubbling upward (separately) the gasses will cause a steady flow of water upward, which continues to power the turbines as an air pump does (see link)

If a sufficient percentage of power is returned to the process, it:

1. May cause the process to be steady and continuous, despite the changing power of the sea currents.

2. May even be of practical value (I'm thinking 20% or more...)

Is there a way to figure in advance how much energy can be retrieved from this?


Some extra thoughts to be discussed only if the main idea isn't debunked:

Possible additions:

1. The turbine itself serves as the set of electrodes - either the rotor is one electrode (say anode) while the stator is a different electrode (say cathode), or the rotors are built of an anode and cathode with some electric insulation between them.

2. Water and gas emit from top of pipe from an exit thinner than the entrance to the pipe at the bottom, causing a "venturi effect" for the sea current.

3. The oxygen can be emited on the peripheral of the pipe while the hydrogen at the center of the pipe. Above the emition of hydrogen an extra pipe can be inserted within the main pipe, keeping the gasses separated

pashute, Oct 05 2016

Airlift pump https://en.wikipedi...g/wiki/Airlift_pump
[pashute, Oct 05 2016]

Lake Nyos degassing https://en.wikipedi...Lake_Nyos#Degassing
A self-sustaning "bubble" pump [8th of 7, Oct 05 2016]


       //This idea is NOT about perpetual motion or anything of the sort.//   

       So, you are putting in electricity to do the electrolysis, above and beyond the electricity generated by the turbine?   

       You won't get any net energy out of such a system. Electrolysis under high pressure (as at the bottom of the tube) will require more energy than electrolysis under low pressure. In other words, you get no net benefit from using the rising bubbles.
MaxwellBuchanan, Oct 05 2016

       Because of the dissolved salts in sea water, you're going to get Chlorine liberated along with the Oxygen.   


       OK ... so gas is liberated at depth. It rises up the water column, pushing water above it; thus it has potential energy.   

       The question is, how much ? It will probably be necessary to approach this via a simplified approximation.   

       Consider 1 litre of gas (at STP) at a depth of 100m. It will be at a pressure of 1 Bar for every ten metres of depth, thus under a pressure of 10Bar it will have a volume of 0.1 l. As the bubble rises, its volume will increase in proportion to the decrease in pressure.   

       As the relationship is linear, the lifting force over the range can be approximated to the force at 50m (0.5 l) over the full range. So, the buoyancy force is equivalent to 5N over a 100m travel.   

       That's 50 J of energy. How much of that can be recovered ?   

       Water turbines can be quite efficient, but being pessimistic, say 50%, including generation losses. A pipe operating at 1l/s at the surface would produce 25W.   

       How much electrical energy is needed to liberate 1 litre of gas ?   

       PEM gives a figure of 4.5 kWh/m3 which is 4.5 Wh/litre. 1 Wh is 3600J. That's about 7 times the recovered energy from the turbine.   

       But you still have the electrolysis gas, but because it's sea water it will be "dirty". Hmmm.
8th of 7, Oct 05 2016

       8th, are you saying one 7th?
pashute, Oct 15 2016


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