Antisolvent process for treating liquids that include high total dissolved solids

• US 9,416,033 B2
• Filed: 12/06/2012
• Issued: 08/16/2016
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Drake Water Technologies, Inc.
• Original Assignee: Drake Water Technologies, Inc.
• Inventors: Drake, Ronald N.
• Primary Examiner(s): Mellon, David C
• Application Number:
  US13/706,943
• Publication Number:
  US 20130140234A1
• Time in Patent Office: 1,349 Days
• US Class Current: 1/1
• CPC Class Codes: C02F 1/02 by heating methods of steam generation F22B; preheating boiler feed-water or accumulating preheated boiler feed-water F22D
• CPC Class Codes: C02F 1/16 using waste heat from other processes
• CPC Class Codes: C02F 1/38 by centrifugal separation
• CPC Class Codes: C02F 1/441 by reverse osmosis
• CPC Class Codes: C02F 1/5272 using specific organic precipitants
• CPC Class Codes: C02F 2001/007 Processes including a sedimentation step
• CPC Class Codes: C02F 2001/5218 Crystallization
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage

Abstract

The present invention provides a low energy alternative to conventional thermal/evaporation processes for “zero liquid discharge” treatment of strong saline brines. The products of the process include a salt-free liquid and solid salt. In particular, an antisolvent can be mixed with liquids containing high total dissolved solids. The mixture can be chilled, whereby solid salt is precipitated and separated from the mixture at near ambient temperature leaving a mixed liquor. The antisolvent can be selected from a class of organic compounds that form solutions with salt brines that exhibit a critical solution temperature lower than a critical solution temperature of the salt brines alone. The mixed liquor can be heated to a temperature above its lower critical solution temperature to produce an antisolvent liquid phase for recycle to the process. Finally, a reduced salinity aqueous phase can be polished by reverse osmosis or other conventional technology to produce clean water for discharge or beneficial use.

Claims

1. A system for treating a high total dissolved solids liquid, the system comprising:

a temperature-reduction vessel that receives a high TDS liquid and an antisolvent such that a mixture is formed inside the temperature-reduction vessel at a temperature below a critical solution temperature of the mixture, thereby causing precipitation of salt and production of a salt slurry;

a separator receiving the salt slurry and separating the salt slurry into a mixed liquor and a salt cake;

a heating vessel receiving the salt cake and applying heat to the salt cake to produce dry salt and a mixed vapor;

a phase separator receiving a recuperated mixed liquor, a temperature of the recuperated mixed liquor in the phase separator being greater than a lower critical solution temperature of the recuperated mixed liquor, and thus causing the recuperated mixed liquor to separate into an antisolvent phase and an aqueous phase;

a recuperator receiving the antisolvent phase and the mixed liquor and indirectly transferring heat from the antisolvent phase to the mixed liquor thus turning the mixed liquor into the recuperated mixed liquor;

a heater that applies heat to the recuperated mixed liquor such that the temperature of the recuperated mixed liquor in the phase separator is greater than the lower critical solution temperature of the recuperated mixed liquor; and

a fluid path between the phase separator and the temperature-reduction vessel for passing antisolvent back into the temperature-reduction vessel,

wherein the phase separator is coupled to the heating vessel, the heater, and the recuperator.

2. The system of claim 1, further comprising a polisher that polishes the aqueous phase producing clean water and returning any solution having a concentration of salt to the temperature-reduction vessel.

3. The system of claim 2, wherein the antisolvent is at a lower temperature than the solution having a concentration of salt therein.

4. The system of claim 2, wherein the phase separator includes a mixed vapor input coupled to a mixed vapor output of the heating vessel, the mixed vapor input configured to receive the mixed vapor from the heating vessel.

5. The system of claim 1, wherein the recuperator includes a first antisolvent output coupled to an input of the temperature-reduction vessel and configured to pass antisolvent to the temperature-reduction vessel.

6. The system of claim 1, wherein the phase separator includes a second antisolvent output coupled to an input of the recuperator and configured to pass antisolvent to the recuperator.

7. A system for treating a high total dissolved solids liquid, the system comprising:

a temperature-reduction vessel that receives a high TDS liquid and an antisolvent such that a mixture is formed inside the temperature-reduction vessel at a temperature below a critical solution temperature of the mixture, thereby causing precipitation of salt and production of a salt slurry;

a separator receiving the salt slurry and separating the salt slurry into a mixed liquor and a salt cake;

a heating vessel receiving the salt cake and applying heat to the salt cake to produce dry salt and a mixed vapor;

a phase separator receiving a recuperated mixed liquor, a temperature of the recuperated mixed liquor in the phase separator being greater than a lower critical solution temperature of the recuperated mixed liquor, and thus causing the recuperated mixed liquor to separate into an antisolvent phase and an aqueous phase, the phase separator including a mixed vapor input coupled to a mixed vapor output of the heating vessel, the mixed vapor input configured to receive the mixed vapor from the heating vessel;

a recuperator receiving the antisolvent phase and the mixed liquor and indirectly transferring heat from the antisolvent phase to the mixed liquor thus turning the mixed liquor into the recuperated mixed liquor; and

a heater that applies heat to the recuperated mixed liquor such that the temperature of the recuperated mixed liquor in the phase separator is greater than the lower critical solution temperature of the recuperated mixed liquor.

8. The system of claim 7, wherein the temperature reduction vessel maintains liquids therein at a steady-state temperature at or below 25°

C.

9. The system of claim 7, further comprising a polisher that polishes the aqueous phase producing clean water and returning any solution having a concentration of salt to the temperature-reduction vessel.

10. The system of claim 7, wherein the antisolvent is at a lower temperature than the solution having a concentration of salt therein.

11. A system comprising:

a temperature control vessel having an input and an output, the input configured to receive high TDS waste fluids;

a separator coupled to the output of the temperature control vessel and having a first and second output;

a dryer coupled to the first output of the separator and having a first and second output;

a heater coupled to the second output of the separator via a first path and further having an output; and

a phase separator having a first and second input and a first and second output, the first input of the phase separator coupled to the first output of the dryer, the second input of the phase separator coupled to the output of the heater, the first output of the phase separator coupled to the input of the temperature control vessel via a second path.

12. The system of claim 11, further comprising a polisher coupled to the second output of the phase separator, and having a first and second output, the first output of the polisher coupled to the input of the temperature control vessel.

13. The system of claim 11, wherein the temperature control vessel is configured to chill fluids therein to below a lower critical solution temperature or heat fluids therein to above an upper critical solution temperature, and wherein the phase separator is configured to heat fluids therein to above the lower critical solution temperature or chill fluids therein to below the upper critical solution temperature.

14. The system of claim 13, wherein the lower critical solution temperature is 25°

C. or lower.

15. The system of claim 11, wherein the second path between the phase separator and the temperature control vessel includes a recuperator, and the first path between the separator and the heater includes the recuperator, wherein the recuperator is arranged to transfer thermal energy between the first path and the second path.

16. The system of claim 15, wherein the recuperator is arranged so as to preclude direct physical contact between liquids in the first and second paths.