Recovery of retrograde soluble solute for forward osmosis water treatment
AssigneeTrevi Systems Inc.
InventorsGary Carmignani, Steve Sitkiewitz, John Wilfred Webley
Life of this patent
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Abstract
Improved systems and processes for forward osmosis water purification or desalination are herein disclosed. According to one embodiment a process for purifying contaminated water is provided wherein a contaminated feed solution stream comprising water and with a first osmotic pressure is passed through a semipermeable membrane to a draw side having a draw solution stream with a second osmotic pressure on a draw side of the semipermeable membrane. The diluted draw solution stream is heated, agglomerated and cooled to produce a cooled single phase water rich stream that is purified to produce a water product stream.
Claims23
A process for purifying contaminated water comprising:
- providing a contaminated feed solution stream comprising water and having a first osmotic pressure on a feed side of a semipermeable membrane;
- providing a liquid draw solution stream comprising a liquid draw solute and having a second osmotic pressure on a draw side of the semipermeable membrane;
- passing water through the semipermeable membrane to the draw side to produce a diluted draw solution stream;
- heating the diluted draw solution stream to initiate phase separation and produce a two phase effluent stream comprising a liquid phase of draw solute and a liquid phase of water;
- agglomerating the draw solute in the two phase effluent stream using a coalescer to produce a two phase effluent stream comprising a liquid phase of agglomerated draw solute and a liquid phase of water;
- separating the agglomerated draw solute from the two phase effluent stream using a gravity phase separator to produce a water rich stream comprising water and residual draw solute and a solute rich stream comprising agglomerated draw solute and water;
- cooling the water rich stream to produce a cooled single phase water rich stream;
- and
- separating the residual draw solute from the cooled single phase water rich stream to produce a residual draw solute stream and a purified water product stream.
A system for purifying contaminated water comprising:
- a semipermeable membrane comprising a feed side for receiving a contaminated feed solution stream comprising water and having a first osmotic pressure and a draw side for receiving a liquid draw solution stream comprising a liquid draw solute and having a second osmotic pressure, wherein the semipermeable membrane is configured to pass water from the contaminated feed solution stream to the draw side to produce a diluted draw solution stream;
- a first heat exchanger configured for heating the diluted draw solution stream to initiate phase separation and produce a two phase effluent stream comprising a liquid phase of draw solute and a liquid phase of water;
- a coalescer configured for agglomerating the draw solute in the diluted draw solution stream to produce an agglomerated two phase effluent stream comprising a liquid phase of agglomerated draw solute and a liquid phase of water;
- a gravity phase separator configured for separating the agglomerated draw solute from the agglomerated two phase effluent stream to produce a water rich stream comprising water and residual draw solute and a solute rich stream comprising agglomerated draw solute and water;
- a second heat exchanger configured for cooling the water rich stream to produce a cooled single phase water rich stream;
- and
- a reverse osmosis module configured for separating the residual draw solute from the cooled single phase water rich stream to produce a residual draw solute stream and a purified water product stream.
Dependencies are inferred from the claim text.