CRYSTALLIZER FOR WATER RECLAMATION

Abstract

A crystallizer for use in treating produced water is disclosed. The crystallizer is a combination of a source of nitrogen in fluid communication with at least one connecting tube which is in fluid communication with a chamber which is in fluid communication with a discharge tube. The produced water from an oil and gas operation is fed into the crystallizer which will separate out contaminants from the water producing fresh water.

Claims

1. A crystallizer comprising a source of nitrogen in fluid communication with at least one connecting tube which is in fluid communication with a chamber which is in fluid communication with a discharge tube.

2. The crystallizer as claimed in claim 1 wherein the nitrogen is gaseous nitrogen and liquid nitrogen.

3. The crystallizer as claimed in claim 1 wherein the source of nitrogen is in fluid communication with at least one connecting tube by a nozzle.

4. The crystallizer as claimed in claim 1 wherein the at least one connecting tube is a plurality of connecting tubes.

5. The crystallizer as claimed in claim 1 wherein when a plurality of connecting tubes is present each successive connecting tube is greater in diameter than the connecting tube preceding it.

6. The crystallizer as claimed in claim 1 wherein a source of feedwater is in fluid communication with the at least one connecting tube.

7. The crystallizer as claimed in claim 6 wherein the feedwater is produced water from an oil and gas operation.

8. The crystallizer as claimed in claim 7 wherein the feedwater and gaseous nitrogen rise through the at least one connecting tube.

9. The crystallizer as claimed in claim 1 wherein the gaseous nitrogen will change velocity it rises through the at least one connecting tube.

10. The crystallizer as claimed in claim 9 wherein the nitrogen provides agitation inside of the at least one connecting tube.

11. The crystallizer as claimed in claim 1 wherein salt crystals and ice crystals separate in the at least one connecting tube.

12. The crystallizer as claimed in claim 1 wherein the at least one connecting tube is present in the chamber.

13. The crystallizer as claimed in claim 1 wherein the chamber holds a fluid.

14. The crystallizer as claimed in claim 1 wherein water is sprayed from the connecting tube into the chamber.

15. The crystallizer as claimed in claim 1 wherein the water sprayed contains ice crystals.

16. The crystallizer as claimed in claim 15 wherein the discharge tube discharges water.

17. The crystallizer as claimed in claim 1 wherein salts are recovered from the at least one connecting tube.

18. The crystallizer as claimed in claim 1 wherein the crystallizer is mounted on a skid.

19. The crystallizer as claimed in claim 1 wherein the flow of nitrogen is continuous.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is a schematic of a crystallizer as described in the present invention.

[0033] FIG. 2 is a schematic of the interaction of two or more crystallizers.

DETAILED DESCRIPTION OF THE INVENTION

[0034] FIG. 1 shows a low-energy, direct contact crystallizer that can be employed for reclaiming produced water. The main crystallizer housing 1 is designed to crystallize the incoming produced water stream 5 into salt and ice crystals through the use of a cryogenic fluid such as liquid nitrogen 6. The crystallizer will also separate the salt and water crystals through a multi-diameter draft tube 2 from the top of the draft tube 2 to a chamber 11 where through a water spray 12 the crystals are converted into fresh water stream and this reclaimed water stream is removed through discharge pipe 13.

[0035] Liquid nitrogen and gaseous nitrogen (GAN) are both fed through line 6. They both provide cooling required for the eutectic freeze crystallization of the produced water. The gaseous streams also provide energy required for agitation and through the multi-diameter draft tube 2 provides separation of water crystals from salt solution and salt crystals.

[0036] As such, three effects are achieved, namely heat transference, inducing agitation and separation without a pump or agitator motor being present.

[0037] The draft tube 2 is divided into several sections of increasing diameter as the flow of fluid progresses upwards. The LIN and/or GAN are fed through nozzle 6 into connecting tube 7 which is fluidly connected to nozzle 6. Connecting tube 7 is fluidly connected to connecting tube 8 which is larger in diameter than connecting tube 7. Connecting tube 8 fluidly connects to connecting tube 9 which is greater in diameter than connecting tube 8. For purposes of FIG. 1, connecting tube 9 fluidly connects to connecting tube 10 which is larger in diameter than connecting tube 9.

[0038] As the GAN rises through the draft tube 2 which comprises the connecting tubes 7, 8 and 9, its velocity changes and decreases because of the increase in diameter through the respective connecting tubes. This decrease in velocity will lead to a separation in the crystals formed (ice crystals versus salt crystals) and the ice crystals, being lighter will require a lower terminal falling velocity. The salt crystals being heavier will require a higher terminal falling velocity. So as the GAN rises along the draft tube 2, the heavy crystals of salt will settle down and the lighter ice crystals will be directed to the spray chamber 11 where they are sprayed with a portion of the portion of fresh water and withdrawn as reclaimed water stream 13.

[0039] The nozzle 6 is designed to fluidly connect to the first connecting tube 7 and to feed either or both GAN and LIN to the connecting tube 7. Feed water is also fed to connecting tube 7 through line 5 which is shown as two separate feed lines in fluid communication with connecting tube 7. This feed water through line 5 can be the water that is going to be subject to treatment such as the produced water from an oil and gas operation.

[0040] A chamber 3 is present to collect the salt crystals. Pipe 4 which is present in the bottom of chamber 3 will assist in removing the salt crystals out of the crystallizer.

[0041] FIG. 2 is a schematic representation of more than one crystallizer working in conjunction with each other. This schematic simply shows the crystallizer as described with respect to the description of FIG. 1 and particularly the draft tube 2 for three crystallizers. This demonstrates that the present invention can address greater flow rates by increasing the number of draft tube assemblies to two or three depending upon the increased flow rate. This also allows for the present invention to be similar to traditional membrane based reverse osmosis units for flow rates.

[0042] 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.