Process for the production of hydraulic energy and production of potable water by direct osmosis

An installation for production of hydraulic energy by direct osmosis from two saline solutions having different concentrations, comprising:

• a module of inverse osmosis semipermeable membranes comprising
• a casing,
• two separate supply inlets for the solutions inside the module, the two separate supply inlets including a first supply for brine and a second supply inlet for brackish water,
• two separate outlets for two respective flows generated inside the module by means of direct osmosis, the two separate outlets including a first outlet for a diluted brine flow, and a second outlet for a concentrated brackish water flow, and
• semipermeable membranes separating the two solutions from their entry into the module until their exit thereof,
• wherein the module of inverse osmosis semipermeable membranes are a module of hollow fibre semipermeable membranes with a double inlet and outlet port having the following characteristics
• product flow (permeate):
• 34 m3/D;
• minimum product flow (permeate):
• 32 m3/D;
• salt rejection:
• 99.6%;
• minimum salt rejection:
• 99.4%
• maximum pressure in working conditions:
• 8.23 MPa;
• temperature range in working conditions:
• between 5° C.-40° C.;
• and
• brine flow in working conditions:
• higher than or equal to 25-120 m3/D;
• a first hydraulic pump feeding a brine flow towards the interior of the module at a pressure P1 through the first supply inlet thereof, P1 being lower than the osmotic pressure difference between the osmotic pressure of the brine and the osmotic pressure of the brackish water;
• a second hydraulic pump, connected to a tertiary waste water treatment plant from which the brackish water comes from, feeding said brackish water flow at a pressure P2 towards the interior of the module through the second supply inlet thereof, the pressure P2 being sufficient to overcome load losses through the module of membranes plus a necessary pressure for final disposal of the concentrated brackish water;
• a device connected to the diluted brine flow outlet of the module, the device comprising at least one hydraulic turbine producing energy by means of the passage of the diluted brine flow;
• and
• a third hydraulic pump driving the diluted brine flow after its passage through the device comprising the at least one turbine, to an inlet of a water desalination plant by inverse osmosis to produce supplementary water of potable quality.