Osmotically-assisted desalination method and system

摘要

Systems and methods for osmotically assisted desalination include using a pressurized concentrate from a pressure desalination process to pressurize a feed to the desalination process. The depressurized concentrate thereby produced is used as a draw solution for a pressure-retarded osmosis process. The pressure-retarded osmosis unit produces a pressurized draw solution stream that is used to pressurize another feed to the desalination process. In one example, the feed to the pressure-retarded osmosis process is impaired water.

主权项

1. A water treatment method comprising:
passing a first solute stream through a low pressure inlet of a first pressure exchanger to produce a pressurized first solute stream; passing the pressurized first solute stream through a booster pump and through an inlet of a pressure desalination unit to produce a stream of desalinated water and a pressurized concentrate stream; passing the pressurized concentrate stream into a high pressure inlet of the first pressure exchanger to produce a depressurized concentrate stream, wherein the pressure from the pressurized concentrate stream is transferred to the first solute stream to produce the pressurized first solute stream; passing the depressurized concentrate stream into a draw solution side of a pressure-retarded osmosis unit; passing a stream of impaired water into a feed side of the pressure-retarded osmosis unit, wherein water from the impaired water crosses a membrane in the pressure-retarded osmosis unit and enters and pressurizes the depressurized concentrate stream, producing a pressurized diluted draw solution stream; passing the pressurized diluted draw solution stream through a high pressure inlet of a second pressure exchanger; passing a second solute stream through a low pressure inlet of the second pressure exchanger, wherein pressure from the pressurized diluted draw solution stream is transferred to the second solute stream to produce a pressurized second solute stream and a depressurized diluted draw solution stream; and passing the pressurized solute stream through the inlet of the pressure desalination unit.