US 11,667,549 B2
Osmotic methods and systems involving energy recovery
Richard Stover, Waltham, MA (US)
Assigned to Gradiant Corporation, Woburn, MA (US)
Filed by Gradiant Corporation, Woburn, MA (US)
Filed on Aug. 8, 2022, as Appl. No. 17/882,701.
Application 17/882,701 is a continuation of application No. PCT/US2021/059441, filed on Nov. 16, 2021.
Claims priority of provisional application 63/114,643, filed on Nov. 17, 2020.
Claims priority of provisional application 63/114,656, filed on Nov. 17, 2020.
Claims priority of provisional application 63/114,648, filed on Nov. 17, 2020.
Claims priority of provisional application 63/114,652, filed on Nov. 17, 2020.
Prior Publication US 2022/0380233 A1, Dec. 1, 2022
Int. Cl. C02F 1/44 (2023.01); C02F 1/26 (2023.01); B01D 61/06 (2006.01); B01D 61/02 (2006.01)
CPC C02F 1/441 (2013.01) [B01D 61/06 (2013.01); C02F 1/265 (2013.01); B01D 61/026 (2022.08); B01D 2317/022 (2013.01); C02F 2301/066 (2013.01); C02F 2303/10 (2013.01)] 51 Claims
OG exemplary drawing
 
9. 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 a recirculation stream comprising a first portion of the first reverse osmosis unit retentate outlet stream, wherein the recirculation stream is combined with the at least a portion of the pressurized energy recovery stream prior to incorporation into the first reverse osmosis unit retentate inlet stream;
the second reverse osmosis unit retentate inlet stream comprises a second portion of the first reverse osmosis unit retentate outlet stream; and
the energy recovery stream comprises at least a portion of the second reverse osmosis unit permeate outlet stream.