Osmotic methods and systems involving energy recovery
AssigneeGradiant Corporation
InventorRichard Stover
Life of this patent
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Abstract
Liquid solution concentration methods and related systems involving osmosis units and energy recovery are generally described. In some embodiments, an osmotic system has a pump, a first reverse osmosis unit, a second reverse osmosis unit, and one or more energy recovery devices. Various embodiments are directed to features such as balancing streams, recirculation streams, and/or valving that alone or in combination may afford improved energy efficiency and/or system performance. Some embodiments may improve performance of certain types of energy recovery devices in combination with osmosis units, such as isobaric or turbine energy recovery devices.
Claims20
A method, comprising:
- increasing a pressure of at least a portion of a feed stream comprising a solvent and a solute to form a pressurized feed stream;
- transporting a first reverse osmosis unit retentate inlet stream to a retentate side of a first reverse osmosis unit such that:
- a first reverse osmosis unit retentate outlet stream exits the retentate side of the first reverse osmosis unit, the first reverse osmosis unit retentate outlet stream having an osmotic pressure that is greater than an osmotic pressure of the first reverse osmosis unit retentate inlet stream, and
- at least a portion of liquid from the first reverse osmosis unit retentate inlet stream is transported from the retentate side of the first reverse osmosis unit, through an osmotic membrane of the first reverse osmosis unit, to a permeate side of the first reverse osmosis unit;
- transporting a second reverse osmosis unit retentate inlet stream to a retentate side of a second reverse osmosis unit such that:
- a second reverse osmosis unit retentate outlet stream exits the retentate side of the second reverse osmosis unit, the second reverse osmosis unit retentate outlet stream having an osmotic pressure that is greater than an osmotic pressure of the second reverse osmosis unit retentate inlet stream, and
- at least a portion of liquid from the second reverse osmosis unit retentate inlet stream is transported from the retentate side of the second reverse osmosis unit, through an osmotic membrane of the second reverse osmosis unit, to a permeate side of the second reverse osmosis unit where the portion of the liquid forms some or all of a second reverse osmosis unit permeate outlet stream that is transported out of the permeate side of the second reverse osmosis unit;
- reducing a pressure of at least a portion of the second reverse osmosis unit retentate outlet stream to form a reduced-pressure concentrate stream;
- and
- using at least a portion of energy recovered from the reducing of the pressure of the at least a portion of the second reverse osmosis unit retentate outlet stream to increase a pressure of an energy recovery stream to form a pressurized energy recovery stream;
- wherein:
- the first reverse osmosis unit retentate inlet stream comprises at least a portion of the pressurized feed stream, at least a portion of the pressurized energy recovery stream, and at least a portion of the second reverse osmosis unit permeate outlet stream;
- the second reverse osmosis unit retentate inlet stream comprises at least a portion of the first reverse osmosis unit retentate outlet stream;
- and
- the energy recovery stream comprises a balancing stream comprising at least a portion of the feed stream.
Dependencies are inferred from the claim text.