Osmotic power plant

Osmotic power plant.



Osmotic power – power plant for generating electrical energy due to the diffusion of liquids (process of osmosis).


Description of osmotic power plants and the principle of its operation

The advantages of osmotic power plant


Description of osmotic power plants and the principle of its operation:

Osmotic power – power plant for generating electric energy due to the diffusion of liquids (process of osmosis).

Under the osmosis (from the Greek. ὄσμος — push pressure) refers to the process of unilateral diffusion through a semipermeable membrane of solvent molecules in the direction of greater concentration of dissolved substance of volume with a lower concentration of solute. The phenomenon of osmosis is observed in environments where the mobility of the solvent more solute mobility. An important special case of osmosis is osmosis through a semi-permeable membrane.

The principle of osmotic power plant based on mixing of salt and fresh water. Mixing takes place in the reservoir, which is divided into two compartments semi-permeable membrane. Called a semi-permeable membranethat has sufficiently high permeability is not for everyone, but for some substances, in particular, for solvent (which is water or water molecules). The mobility of the dissolved substances (i.e. salt) in the membrane is relatively small. In one compartment of the sea water and the other fresh. Due to different salt concentration in marine and fresh water, the molecules of water (solution) from the freshwater compartment in an effort to equalize the concentration of salt pass through the membrane into the compartment with sea water. The result of a blend of molecules of water (solution) through a semi-permeable membrane in the compartment with sea water is formed by the excess pressure, which in turn is used to rotate turbines, generating electricity. This osmotic pressure arises from the fact that the system tries to equalize the concentration of a solution (water molecules) in both compartments (the principle of Le Chatelier), separated by a membrane and is described by the second law of thermodynamics. It is equal to the excess external pressure that should be applied from solution (water molecules) to stop the process, i.e. to create the conditions of osmotic equilibrium.

When the concentration of the salt in 35 g/liter by osmosis creates a pressure 2 389 464 Pascal, or about 24 atmospheres, which corresponds to a dam height of 240 m.

The pressure force (the osmotic force) depends on the area of the membrane, its permeability and selectivity. Membrane that are necessary for the operation of osmotic power plants, similar to those used in industry for desalination of water, but should be much thinner.

Currently, the efficiency of membranes is about 1 W/m2. The index, which will make the osmotic power plant is profitable (commercially available) and 5 watts/m2.

The use of the osmotic power plant is limited to only the mouths of rivers where fresh water flows into the salt water of the sea.

On assurances of scientists, if the osmotic power plant will be installed in the mouth of every river on the planet Earth, they will be able to provide 20% of world electricity demand.


The advantages of osmotic power plant:

– an alternative renewable energy source

– unlike the wind and sun is a continuous, renewable source of energy,

– there is no greenhouse effect,

– 100% environmental friendliness.


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