CRYSTALLIZER AND METHOD FOR WATER RECLAMATION

Abstract

A method and crystallizer for treating produced water through the steps of feeding produced water to a porous pipe in a chamber wherein the chamber is cylindrically shaped having an interior wall with a top and a bottom; feeding gaseous nitrogen to a nozzle present in the chamber, which is in fluid communication with an interior pipe; feeding the produced water to the interior pipe wherein slush is formed in the pipe and this slush is forced through the interior pipe to the top of the chamber; operating at least one scraper which is mounted circumferentially about the porous pipe and having arms that extend outwardly from the scraper center in contact with the interior wall of the chamber wherein the scraper will remove salt crystals from the interior walls of the chamber; recovering salt crystals from the bottom of the chamber; and recovering fresh water from the chamber.

Claims

1. A crystallizer comprising a chamber being cylindrical in shape and comprising an interior wall and a top and a bottom, the chamber being in fluid communication with a pipe for introducing produced water, the pipe is in fluid communication with a porous pipe to allow for distribution of the produced water through the interior of the chamber; a source of gaseous nitrogen in fluid communication with a nozzle wherein the nozzle is located inside the chamber and is in fluid communication with an interior pipe which is further in fluid communication with the produced water; at least one scraper which is mounted circumferentially about the porous pipe and having arms that extend outwardly from the scraper center in contact with the interior wall of the chamber thereby scraping salt crystals on the interior wall of the chamber; and a top pipe in fluid communication with the chamber thereby to remove fresh water from the chamber.

2. The crystallizer as claimed in claim 1 wherein the produced water is from an oil and gas production process.

3. The crystallizer as claimed in claim 1 wherein the gaseous nitrogen is formed by feeding liquid nitrogen to a fluid temperature control system.

4. The crystallizer as claimed in claim 1 wherein gaseous nitrogen is recovered from the chamber and fed to the fluid temperature control system.

5. The crystallizer as claimed in claim 1 wherein the porous pipe distributes the produced water throughout the chamber.

6. The crystallizer as claimed in claim 1 wherein the nozzle feeds produced water and gaseous nitrogen to the interior pipe.

7. The crystallizer as claimed in claim 1 wherein slush or ice crystals are formed in the interior pipe.

8. The crystallizer as claimed in claim 1 wherein the scraper is operated periodically.

9. The crystallizer as claimed in claim 1 wherein the scraper rotates between 0 and 180.

10. The crystallizer as claimed in claim 1 having salts removal means from the bottom of the chamber.

11. A method for treating produced water comprising the steps of: a) Feeding produced water to a porous pipe in a chamber wherein the chamber is cylindrically shaped having an interior wall with a top and a bottom; b) Feeding gaseous nitrogen to a nozzle present in the chamber, wherein the nozzle is in fluid communication with an interior pipe; c) Feeding the produced water to the interior pipe wherein slush is formed in the pipe and this slush is forced through the interior pipe to the top of the chamber; d) Operating at least one scraper which is mounted circumferentially about the porous pipe and having arms that extend outwardly from the scraper center in contact with the interior wall of the chamber wherein the scraper will contact and remove salt crystals from the interior walls of the chamber; e) Recovering salt crystals from the bottom of the chamber; and f) Recovering fresh water from the chamber.

12. The method as claimed in claim 11 wherein the produced water is from an oil and gas production process.

13. The method as claimed in claim 11 wherein the gaseous nitrogen is formed by feeding liquid nitrogen to a fluid temperature control system.

14. The method as claimed in claim 11 wherein gaseous nitrogen is recovered from the chamber and fed to the fluid temperature control system.

15. The method as claimed in claim 11 wherein the porous pipe distributes the produced water throughout the chamber.

16. The method as claimed in claim 11 wherein the nozzle feeds produced water and gaseous nitrogen to the interior pipe.

17. The method as claimed in claim 11 wherein slush or ice crystals are formed in the interior pipe.

18. The method as claimed in claim 11 wherein the scraper is operated periodically.

19. The method as claimed in claim 11 wherein the scraper rotates between 0 and 180.

20. The method as claimed in claim 11 wherein salts are removed from the bottom of the chamber.

21. The method as claimed in claim 11 wherein the fresh water is recovered from the chamber through a top pipe.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The figure is a schematic of a crystallizer for use in the methods of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0033] A crystallizer 1 is shown in the Figure as well as a schematic of the operation of the crystallizer in the method of the invention. Produced water from an oil and gas production process is fed through line 4 to a porous pipe G which will distribute the produced water throughout the chamber C.

[0034] Liquid nitrogen is fed from a liquid nitrogen source A through line 1 to a fluid temperature control system B which will cool the liquid nitrogen and form gaseous nitrogen. Such a system may be a CUMULUS system available from Linde AG. The gaseous nitrogen is fed from the fluid temperature control system B through line 2 to the chamber C where it will enter a nozzle D.

[0035] The nozzle D will also be in fluid communication with the produced water present in chamber C and will direct the produced water and gaseous nitrogen to an interior pipe F where they will form slush or ice crystals in the interior pipe F. This slush or ice crystals will be forced through the top of the interior pipe F where they can be recovered as fresh water from the chamber through line 6.

[0036] The gaseous nitrogen will be recovered from the top of the chamber C where it will be fed through line 7 to the fluid temperature control system B where it can then be cooled in temperature and fed through line 8 back to the chamber C and nozzle D.

[0037] A scraper E is mounted circumferentially around the porous pipe G. The scraper E will have arms extending outwards from its center and these arms will contact at least a portion of the height of the interior wall of the chamber C. This scraper will be driven by an electric motor or exhaust gaseous nitrogen. This scraper E will be operated periodically and the arms will contact salts that have formed on the interior walls of the chamber C. These salts are the byproducts of contaminants present in the produced water and will be separated out as a result of the operation of the crystallizer 1. The salts will be removed from the bottom of the chamber C through line 5 where they can be recovered, purified further as necessary and reused in suitable industrial operations or disposed of in an environmentally responsible manner.

[0038] While this invention has been described with respect to particular embodiments thereof, it is apparent that numerous other forms and modifications of the invention will be obvious to those skilled in the art. The appended claims in this invention generally should be construed to cover all such obvious forms and modifications which are within the true spirit and scope of the invention.