Systems and methods of draw solution recovery with energy saving evaporation supporting forward osmosis membrane crystallization

A forward osmosis membrane crystallizer system for crystallizing sparingly soluble salts from a mixed brine, the forward osmosis membrane crystallizer system comprising:

• an input for introducing the mixed brine into the system;
• at least one of reverse osmosis membrane, nanofiltration membrane, or osmotically assisted reverse osmosis membrane for concentrating or separating the mixed brine;
• an input for introducing one or more antiscalants into the system to suppress crystal formation;
• and
• a forward osmosis membrane crystallizer including at least one forward osmosis membrane and an input for receiving a high osmotic strength draw solution on the permeate side of the at least one forward osmosis membrane of the forward osmosis membrane crystallizer, the input configured to provide the high osmotic strength draw solution having an osmotic pressure greater than an osmotic pressure of the mixed brine osmotic pressure;
• and
• wherein the forward osmosis membrane is configured to concentrate one or more of the sparingly soluble salts in the mixed brine so that a concentration of the sparingly soluble salts becomes above equilibrium saturation until the one or more antiscalants no longer suppresses crystal formation and crystals form on a surface of the at least one forward osmosis membrane.

A forward osmosis membrane crystallizer system for crystallizing sodium chloride to high purity levels around or above 99.0%, the forward osmosis membrane crystallizer system comprising:

• an input for introducing a multivalent ion depleted, highly concentrated monovalent mixed brine stream into the system;
• a forward osmosis membrane crystallizer including at least one forward osmosis membrane;
• and
• an input for introducing a highly concentrated draw solution having an osmotic potential greater than the sodium chloride brine osmotic potential into the system;
• wherein the forward osmosis membrane is configured to allow the highly concentrated at least one draw solution to remove water from the highly concentrated sodium chloride brine stream to a point where the sodium chloride concentration exceeds saturation and crystalizes on the at least one forward osmosis membrane.

A method for crystallizing sodium chloride to high purity levels around or above 99.0%, the method comprising:

• introducing a multivalent ion depleted, highly concentrated monovalent mixed brine stream containing sodium chloride into a forward osmosis membrane crystallizer having at least one forward osmosis membrane;
• providing a flow of highly concentrated draw solution, having an osmotic potential greater than an osmotic potential of the multivalent ion depleted, highly concentrated monovalent mixed brine stream, to a permeate side of the at least one forward osmosis membrane of the forward osmosis membrane crystallizer thereby removing water from the multivalent ion depleted, highly concentrated monovalent mixed brine stream and into the highly concentrated draw solution;
• concentrating the multivalent ion depleted, highly concentrated monovalent mixed brine stream in the forward osmosis membrane crystallizer to a point where a concentration of the sodium chloride exceeds saturation to form crystals on the at least one forward osmosis membrane;
• reconcentrating the highly concentrated draw solution;
• and
• removing the crystals from the at least one forward osmosis membrane.