Control system and method for multiple parallel desalination systems

Patent metadata

Field	Value
Publication number	US-10513445-B2
Application number	US-201715600532-A
Country	US
Kind code	B2
Filing date	May 19, 2017
Priority date	May 20, 2016
Publication date	Dec 24, 2019
Grant date	Dec 24, 2019

Abstract

Embodiments described herein generally relate to humidification-dehumidification desalination systems, including apparatuses that include a vessel comprising a humidification region (e.g., a bubble column humidification region) and a dehumidification region (e.g., a bubble column dehumidification region), mobile humidification-dehumidification (HDH) desalination systems (e.g., systems having a relatively low height and/or a relatively small footprint), and associated systems and methods. Certain embodiments generally relate to methods of operating, controlling, and/or cleaning desalination systems comprising a plurality of desalination units (e.g., HDH desalination units).

First claim

What is claimed is:

1. A method of removing scale, comprising:
providing a desalination system comprising a plurality of desalination units, wherein two or more desalination units of the plurality of desalination units are heat exchanger-containing desalination units that each comprise a humidifier, a dehumidifier, and a first heat exchanger fluidically connected to the humidifier;
flowing a first fluid stream through a first fluidic pathway of the first heat exchanger of each heat exchanger-containing desalination unit;
flowing a second fluid stream through a second fluidic pathway of the first heat exchanger of each heat exchanger-containing desalination unit;
measuring a first temperature of each second fluid stream downstream of the first heat exchanger;
determining a number average first temperature of all the first temperatures measured in the measuring step;
identifying at least one fouled first fluidic pathway characterized by a first temperature measured in the measuring step that differs from the number average first temperature by greater than 10% on the Kelvin scale; and
selectively flowing a de-scaling composition through only the at least one fouled first fluidic pathway.

2. The method of claim 1 , wherein the first fluid stream is a salt-containing water stream.

3. The method of claim 2 , wherein the salt-containing water stream comprises seawater, brackish water, flowback water, water produced from an oil or gas extraction process, and/or wastewater.

4. The method of claim 1 , wherein the second fluid stream is a heating fluid stream.

5. The method of claim 4 , wherein the heating fluid stream comprises water.

6. The method of claim 1 , wherein the first temperature of each second fluid stream is measured at a liquid outlet of the second fluidic pathway of the first heat exchanger.

7. The method of claim 1 , further comprising flowing a first fluid stream from a common source of the first fluid stream to the first heat exchanger of each heat exchanger-containing desalination unit.

8. The method of claim 7 , wherein the common source of the first fluid stream is a central feed tank.

9. The method of claim 1 , further comprising flowing a second fluid stream from a common source of the second fluid stream to the first heat exchanger of each heat exchanger-containing desalination unit.

10. The method of claim 9 , wherein the common source of the second fluid stream is a boiler.

11. The method of claim 1 , further comprising measuring a first temperature of each first fluid stream downstream of the first heat exchanger.

12. The method of claim 11 , wherein the first temperature of each first fluid stream is measured at a liquid outlet of the first fluidic pathway of the first heat exchanger.

13. The method of claim 11 , further comprising selectively increasing a flow rate of a second fluid stream flowing through a first heat exchanger of a heat exchanger-containing desalination unit if the first temperature of the first fluid stream flowing through the first heat exchanger falls below a threshold temperature.

14. The method of claim 13 , wherein the increasing flow rate step is performed by an automatic feedback control system.

15. The method of claim 1 , further comprising measuring a second temperature of each second fluid stream upstream of the first heat exchanger.

16. The method of claim 15 , wherein the second temperature of each second fluid stream is measured at a liquid inlet of the first heat exchanger.

17. The method of claim 15 , further comprising determining a relative standard deviation of all the second temperatures of the first fluid streams or a relative standard deviation of all the second temperatures of the second fluid streams, wherein the relative standard deviation is about 50% or less.

18. The method of claim 17 , wherein the relative standard deviation is about 20% or less.

19. The method of claim 1 , wherein the scale comprises a salt comprising Mg 2+ , Ca 2+ , Sr 2+ , and/or Ba 2+ .

20. A method of removing scale, comprising:
providing a desalination system comprising a plurality of desalination units, wherein two or more desalination units of the plurality of desalination units are heat exchanger-containing desalination units that each comprise a humidifier, a dehumidifier, and a first heat exchanger fluidically connected to the humidifier;
flowing a first fluid stream through a first fluidic pathway of the first heat exchanger of each heat exchanger-containing desalination unit;
flowing a second fluid stream through a second fluidic pathway of the first heat exchanger of each heat exchanger-containing desalination unit;
measuring a first flow rate of each second fluid stream downstream of the first heat exchanger;
determining a number average first flow rate of all the first flow rates measured in the measuring step;
identifying at least one fouled first fluidic pathway characterized by a first flow rate measured in the measuring step that differs from the number average first flow rate by greater than 10%; and
selectively flowing a de-scaling composition through only the at least one fouled first fluidic pathway.

21. The method of claim 20 , wherein the first fluid stream is a salt-containing water stream.

22. The method of claim 20 , wherein the second fluid stream is a heating fluid stream.

23. The method of claim 20 , wherein the first flow rate of each second fluid stream is measured at a liquid outlet of the second fluidic pathway of the first heat exchanger.

24. The method of claim 20 , further comprising flowing a first fluid stream from a common source of the first fluid stream to the first heat exchanger of each heat exchanger-containing desalination unit.

25. The method of claim 24 , wherein the common source of the first fluid stream is a central feed tank.

26. The method of claim 20 , further comprising flowing a second fluid stream from a common source of the second fluid stream to the first heat exchanger of each heat exchanger-containing desalination unit.

27. The method of claim 26 , wherein the common source of the second fluid stream is a boiler.

28. The method of claim 20 , further comprising measuring a first temperature of each first fluid stream downstream of the first heat exchanger.

29. The method of claim 28 , wherein the first temperature of each first fluid stream is measured at a liquid outlet of the first fluidic pathway of the first heat exchanger.

30. The method of claim 20 , wherein the scale comprises a salt comprising Mg 2+ , Ca 2+ , Sr 2+ , and/or Ba 2+ .

Assignees

• Gradiant Corp

Inventors

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

Classifications

• C02F2301/028

  Tortuous · CPC title

• C02F5/08

  Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents · CPC title

• C02F1/10 Primary

  by direct contact with a particulate solid or with a fluid, as a heat transfer medium · CPC title

• C02F2103/365

  from petrochemical industry (e.g. refineries) · CPC title

• C02F2303/22

  Eliminating or preventing deposits, scale removal, scale prevention (C02F1/042, C02F1/4602, C02F5/00 take precedence) · CPC title