Osmotic separation systems and methods

Abstract

The present invention relates generally to osmotically driven membrane systems and processes, and more particularly to systems and processes for treating feed streams without pretreatment and with no increase in brine concentration for zero liquid discharge, including forward osmosis Fractionation (FO), Direct Osmotic Concentration (DOC), Pressure Assisted Forward Osmosis (PAFO) and Pressure Retarded Osmosis (PRO). The system comprises: a plurality of forward osmosis units, each unit having a semipermeable membrane module and a tank; and a separation system in fluid communication with the plurality of forward osmosis units and configured to separate a dilute draw solution into a concentrated draw solution and solvent system.

Description

[0001] Cross References to Related Applications [0002] This application claims priority and benefit to U.S. Provisional Patent Application No. 61 / 976,714, filed April 8, 2014, and U.S. Provisional Patent Application No. 62 / 069,627, filed October 28, 2014; hereby incorporated by reference are incorporated herein in their entirety in their entirety. technical field [0003] One or more aspects relate generally to osmotic separation. More specifically, one or more aspects relate to the separation of solutes from aqueous solutions using an osmotically driven membrane process (eg, forward osmosis). Background technique [0004] Forward osmosis has been used for desalination. Typically, the forward osmosis desalination process involves a vessel with two chambers separated by a semipermeable membrane. One chamber holds sea water. The other chamber contains the concentrated solution, whereby a concentration gradient is created between the seawater and the concentrated solution...

AI Technical Summary

Problems solved by technology

For example, most pretreatment processes make the overall process more expensive by requiring the use of additional energy or chemicals (e.g., lime softening) or further steps (e.g., regeneration of ion exchange resins)

Additionally, the concentrated feed solution may present disposal issues after forward osmosis treatment

For example, highly concentrated brine presents environmental disposal issues, e.g. discharge of concentrated brine into water bodies can adversely affect local ecosystems

While some solutions exist to these problems, they are often expensive and / or add undue complexity to the basic forward osmosis process

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