Methods and systems for producing treated brines for desalination

Patent metadata

Field	Value
Publication number	US-10308526-B2
Application number	US-201514719299-A
Country	US
Kind code	B2
Filing date	May 21, 2015
Priority date	Feb 11, 2015
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

Water treatment systems and associated methods are generally described. Certain embodiments of the water treatment systems and methods described herein may be used to treat water comprising one or more contaminants (e.g., oil, grease, suspended solids, scale-forming ions, volatile organic material) to remove at least a portion of the one or more contaminants. In some embodiments, at least a portion of the treated water may be used directly in certain applications (e.g., oil and/or gas extraction processes). In some embodiments, at least a portion of the treated water may undergo desalination to produce substantially pure water and/or concentrated brine.

First claim

What is claimed is:

1. A method for treating water, comprising:
supplying a first portion of a saline water input stream having a first concentration of a scale-forming ion to an ion-removal apparatus;
removing, within the ion-removal apparatus in a first ion-removal step, at least a portion of the scale-forming ion from the first portion of the saline water input stream by adding at least one ion-removal composition to the ion-removal apparatus to induce precipitation of the portion of the scale-forming ion within the first portion of the saline water input stream and produce a first ion-diminished stream having a second concentration of the scale-forming ion, wherein the second concentration is lower than the first concentration;
collecting a product stream comprising at least a portion of the first ion-diminished stream;
after removing, within the ion-removal apparatus in the first ion-removal step, at least a portion of the scale-forming ion from the first portion of the saline water input stream to produce the first ion-diminished stream, removing, within the ion-removal apparatus in a second ion-removal step, at least a portion of the scale-forming ion from a second portion of the saline water input stream by adding at least one ion-removal composition to the ion-removal apparatus to induce precipitation of the portion of the scale-forming ion within the second portion of the saline water input stream and produce a second ion-diminished stream having a third concentration of the scale-forming ion, wherein the third concentration is lower than the second concentration; and
feeding the second ion-diminished stream to a desalination system to produce a substantially pure water stream having a lower concentration of a dissolved salt than the second ion-diminished stream and a concentrated brine stream having a higher concentration of the dissolved salt than the second ion-diminished stream,
wherein the at least one ion-removal composition that is added to the ion-removal apparatus in the second ion-removal step comprises at least one chemical that:
induces precipitation of scale-forming ions in the second ion-removal step, and
was either not added to the ion-removal apparatus during the first ion-removal step or was added to the ion-removal apparatus during the first ion-removal step in an amount that is different from an amount of the chemical added during the second ion-removal step.

2. The method according to claim 1 , further comprising mixing at least a portion of the first ion-diminished stream and at least a portion of the substantially pure water stream to produce a mixed water stream.

3. The method according to claim 2 , wherein the mixing ratio by mass of the substantially pure water stream to the first ion-diminished stream is in the range of about 2:1 to about 4:1.

4. The method according to claim 2 , wherein the product stream is a first product stream, and further comprising collecting a second product stream comprising at least a portion of the substantially pure water stream, collecting a third product stream comprising at least a portion of the concentrated brine stream, and/or collecting a fourth product stream comprising at least a portion of the mixed water stream.

5. The method according to claim 1 , wherein at least about 5% of the scale-forming ion is removed from the saline water input stream within the ion-removal apparatus to produce the first ion-diminished stream.

6. The method according to claim 1 , wherein the first ion-diminished stream contains the scale-forming ion in an amount of about 5000 mg/L or less.

7. The method according to claim 1 , wherein the second ion-diminished stream contains the scale-forming ion in an amount of about 750 mg/L or less.

8. The method according to claim 1 , further comprising removing, within a separation apparatus fluidically connected to the ion-removal apparatus, at least a portion of a suspended and/or emulsified immiscible phase from the saline water input stream, the first ion-diminished stream, and/or the second ion-diminished stream to form at least one immiscible-phase-diminished stream.

9. The method according to claim 8 , wherein the separation apparatus comprises an induced air flotation (IAF) separator.

10. The method according to claim 8 , further comprising removing, within a suspended solids removal apparatus fluidically connected to the ion-removal apparatus, at least a portion of suspended solids from the saline water input stream, the first ion-diminished stream, the second ion-diminished stream, and/or the at least one immiscible-phase-diminished stream to form at least one suspended-solids-diminished stream.

11. The method according to claim 10 , further comprising increasing or decreasing the pH of the first ion-diminished stream, the second ion-diminished stream, the at least one immiscible-phase-diminished stream, and/or the at least one suspended-solids-diminished stream to form at least one pH-adjusted stream.

12. The method according to claim 11 , further comprising removing, within a volatile organic material (VOM) removal apparatus fluidically connected to the ion-removal apparatus, at least a portion of VOM from the saline water input stream, the first ion-diminished stream, the second ion-diminished stream, the at least one immiscible-phase-diminished stream, the at least one suspended-solids-diminished stream, and/or the at least one pH-adjusted stream to form at least one VOM-diminished stream.

13. The method according to claim 1 , further comprising precipitating at least a portion of the salt from the concentrated brine stream.

14. The method according to claim 1 , wherein the desalination system is a humidification-dehumidification (HDH) desalination system.

15. The method according to claim 14 , wherein the HDH system comprises a bubble column humidifier and/or a bubble column dehumidifier.

16. The method according to claim 1 , wherein the dissolved salt is sodium chloride (NaCl).

17. The method of claim 1 , wherein the at least one ion-removal composition that is added to the ion-removal apparatus in the second ion-removal step comprises at least one chemical that:
induces precipitation of scale-forming ions in the second ion-removal step, and
was not added to the ion-removal apparatus during the first ion-removal step.

18. The method of claim 1 , wherein the at least one ion-removal composition that is added to the ion-removal apparatus in the second ion-removal step comprises at least one chemical that:
induces precipitation of scale-forming ions in the second ion-removal step, and
was added to the ion-removal apparatus during the first ion-removal step in an amount that is different from an amount of the chemical added during the second ion-removal step.

19. The method of claim 1 , wherein the ion-removal apparatus is part of a water treatment system, and further comprising discharging the collected product stream from the water treatment system to be used in an oil and gas extraction operation.

Assignees

• Gradiant Corp

Inventors

• St John Maximus G
• Lam Steven
• Govindan Prakash Narayan

Classifications

• C02F1/42

  by ion-exchange (ion-exchange in general B01J) · CPC title

• C02F1/24

  by flotation (C02F1/465 takes precedence) · CPC title

• C02F1/20

  by degassing, i.e. liberation of dissolved gases (degasification of liquids in general B01D19/00; arrangement of degassing apparatus in boiler feed supply F22D) · CPC title

• C02F9/00 Primary

  Multistage treatment of water, waste water or sewage · CPC title

• C02F1/5236

  using inorganic agents · CPC title