Dispersion and conditioning techniques for thick fine tailings dewatering operations

Patent metadata

Field	Value
Publication number	US-9708206-B2
Application number	US-201314408695-A
Country	US
Kind code	B2
Filing date	Jun 21, 2013
Priority date	Jun 21, 2012
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

Techniques are described that relate to enhancing flocculation and dewatering of thick fine tailings, for example by reducing process oscillations. One example method includes dispersing a flocculant into thick fine tailings having a turbulent flow regime to produce turbulent flocculating tailings; subjecting the turbulent flocculating tailings to shear to build up flocs and increase yield stress, to produce a flocculated material having a non-turbulent flow regime; and shear conditioning the flocculated material to decrease the yield stress and produce conditioned flocculated tailings within a water release zone; and dewatering the conditioned flocculated tailings, for example by employing sub-aerial deposition. The thick fine tailings may have a Bingham Reynolds Number of at least 40,000 upon flocculant addition. Inhibiting process oscillations may include providing turbulent tailings feed, configuring a downstream pipeline assembly to reduce backpressure fluctuations and/or reducing air content in the flocculant solution, for example.

First claim

The invention claimed is:

1. A method of treating thick fine tailings, comprising:
providing an in-line flow of the thick fine tailings;
adding a flocculant into the in-line flow of the thick fine tailings to produce an in-line flow of flocculating tailings material, wherein the in-line flow of the thick fine tailings has a turbulent flow regime upon addition of the flocculant;
shearing the in-line flow of the flocculating tailings material to induce floc build-up, increase a yield stress thereof and reduce turbulence thereof, to thereby produce a non-turbulent, in-line flow of flocculated material;
subjecting the in-line flow of the flocculated material to shear conditioning to decrease the yield stress thereof and produce a conditioned flocculated tailings material that is within a water release zone wherein water separates from the conditioned flocculated tailings material; and
dewatering the conditioned flocculated tailings material.

2. The method of claim 1 , wherein the in-line flow of the thick fine tailings has a Bingham Reynolds Number of at least 40,000 upon addition of the flocculant.

3. The method of claim 1 , wherein the in-line flow of the thick fine tailings has a Bingham Reynolds Number of at least 50,000 upon addition of the flocculant.

4. The method of claim 1 , wherein the in-line flow of the thick fine tailings has a Bingham Reynolds Number of at least 60,000 upon addition of the flocculant.

5. The method of claim 1 , wherein the in-line flow of the thick fine tailings has a Bingham Reynolds Number of between 40,000 and 65,000 upon addition of the flocculant.

6. The method of claim 1 , wherein the flow of the thick fine tailings has a Bingham Reynolds Number of between 45,000 and 60,000 upon addition of the flocculant.

7. The method of claim 1 , wherein providing the turbulent flow regime comprises regulating a feed flow rate of the thick fine tailings above a minimum threshold.

8. The method of claim 1 , wherein providing the turbulent flow regime comprises configuring a pipeline assembly that transports the flow of thick fine tailings for addition of the flocculant and transports the flocculating tailings after addition of the flocculant, to have a sufficiently small pipe diameter.

9. The method of claim 1 , wherein providing the turbulent flow regime comprises ensuring a sufficiently low viscosity of the in-line flow of the thick fine tailings upon addition, of the flocculant.

10. The method of claim 1 , wherein the non-turbulent in-line flow of flocculated material has a laminar flow regime.

11. The method of claim 1 , wherein the in-line flow of the thick fine tailings is provided by pumping at a substantially constant flow rate.

12. The method of claim 1 , wherein the in-line flow of the thick fine tailings is provided by pumping at substantially constant rotations per minute.

13. The method of claim 1 , wherein the adding of the flocculant comprises injecting a solution comprising the flocculant into the in-line flow of the thick fine tailings.

14. The method of claim 13 , wherein the adding of the flocculant is performed by ratio control with respect to the in-line flow of the thick fine tailings.

15. The method of claim 1 , wherein the dewatering comprises depositing the conditioned flocculated tailings material onto a sub-aerial deposition site.

16. The method of claim 1 , wherein the dewatering comprises subjecting the conditioned flocculated tailings material to thickening and/or filtering.

17. A method of dispersing a flocculant into an in-line flow of thick fine tailings, comprising:
providing the in-line flow of the thick fine tailings with a turbulent flow regime to provide a turbulent feed;
adding the flocculant into the turbulent feed to produce an in-line turbulent flow of flocculating tailings material;
shearing the in-line turbulent flow of the flocculating tailings material to induce floc build-up, increase a yield stress thereof and reduce turbulence thereof, to thereby produce a non-turbulent in-line flow of flocculated material.

18. The method of claim 17 , wherein providing the turbulent flow regime comprises regulating a feed flow rate of the thick fine tailings above a minimum threshold; configuring a pipeline assembly to have a sufficiently small pipe diameter, wherein the pipeline assembly transports the turbulent feed and the in-line turbulent flow of flocculating tailings material; and ensuring a sufficiently low viscosity of the in-line flow of the thick fine tailings upon addition of the flocculant.

19. The method of claim 17 , wherein the adding of the flocculant comprises co-annularly injecting a plurality of jets comprising the flocculant into the turbulent feed.

20. The method of claim 19 , wherein the jets comprising the flocculant extend into the turbulent feed co-directionally with the flow direction thereof.

21. A system for treating thick fine tailings, comprising:
a feed pipeline assembly for providing an in-line flow of the thick fine tailings;
a pump for pumping the in-line flow of the thick fine tailings;
an in-line addition assembly in fluid communication with the feed pipeline assembly for adding a flocculant into the in-line flow of the thick fine tailings to produce an in-line flow of flocculating tailings material;
wherein the pump, the feed pipeline assembly and the in-line addition assembly are configured to ensure the thick fine tailings has a turbulent flow regime upon addition of the flocculant;
a floc build-up pipeline assembly in fluid communication with the in-line addition assembly and configured to shear the in-line flow of the flocculating tailings material to increase a yield stress thereof and to produce a non-turbulent in-line flow of flocculated material;
a shear conditioning pipeline assembly configured to shear condition the non-turbulent in-line flow of flocculated material to decrease the yield stress thereof and produce a conditioned flocculated tailings material that is within a water release zone wherein water separates from the conditioned flocculated tailings material; and
a dewatering unit in fluid communication with the shear conditioning pipeline assembly for receiving and dewatering the conditioned flocculated tailings material.

22. The system of claim 21 , wherein the in-line addition assembly comprising an injector for adding a solution comprising the flocculant into the in-line flow of the thick fine tailings.

23. The system of claim 22 , further comprising a flocculant addition controller for controlling the addition of the flocculant into the in-line flow of the thick fine tailings.

24. The system of claim 23 , wherein the flocculant addition controller is configured to provide ratio control of the flocculant with respect to the in-line flow of the thick fine tailings.

25. The system of claim 21 , wherein the dewatering unit comprises a sub-aerial deposition site.

26. A method of treating thick fine tailings, comprising:
dispersing a flocculant into the thick fine tailings having a turbulent flow regime to produce a turbulent flocculating tailings material;
subjecting the turbulent flocculating tailings material to shear to build-up flocs and increase a yield stress thereof, to produce a flocculated material having a non-turbulent flow regime; and
shear conditioning the flocculated material to decrease the yield stress thereof and produce a conditioned flocculated tailings material

Assignees

• Suncor Energy Inc

Inventors

• Bugg Trevor
• Sanchez Ana
• Revington Adrian
• Macaulay James Patrick

Classifications

• C10G7/04 Primary

  Dewatering · CPC title

• C02F2209/40

  Liquid flow rate · CPC title

• C02F1/5281

  Installations for water purification using chemical agents · CPC title

• C02F1/5209

  Regulation methods for flocculation or precipitation · CPC title

• B01D21/01

  using flocculating agents (for purifying water C02F1/52; for liquid radioactive waste G21F9/10) · CPC title