CA2006483C - Accelerated sedimentation of sludge - Google Patents
Accelerated sedimentation of sludgeInfo
- Publication number
- CA2006483C CA2006483C CA 2006483 CA2006483A CA2006483C CA 2006483 C CA2006483 C CA 2006483C CA 2006483 CA2006483 CA 2006483 CA 2006483 A CA2006483 A CA 2006483A CA 2006483 C CA2006483 C CA 2006483C
- Authority
- CA
- Canada
- Prior art keywords
- sludge
- fines
- mixture
- bitumen
- surfactant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Treatment Of Sludge (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
A process is provided for treating the sludge in the tailings pond of a plant which uses the hot water process for extracting bitumen from oil sand. A predetermined quantity of a cationic surfactant is added to the sludge and the mixture is retained for a predetermined time. The mixture is aerated to flocculate and float off the fines and the residual oil, a portion of which is removed. As a result the sedimentation of the sludge is thereby accelerated.
Description
~3;?~ 3
2 The invention relates -to a process for treating the
3 sludge in a tailings pond of plant which uses the hot water
4 process for extractiny bitumen from oil sand.
S BACKGROUND OE' THE INVEN~ION
6 In the Athabasca region of Albe.rta, C~n~a, geological 7 depositions of oil sand occur. T~e:re are ln commercial 8 opera~ion, two plan~s which use the hot water extraction process g for extracting bitumen from the oil sand. The hot water extraction process has been well detailed in both publications 11 and patents.
12 Briefly, the first step of the hot water process 13 involves conditioning the oil sand by mixing the mined. oil sand 14 with hot water and sodium hydroxide in a rotating drum to form a slurry~ The slurry is then screened and diluted with additional 16 hot water prior to being pumped into a flotation/settling vessel.
17 In this vessel, re~erred to as the PSVI most of the solids 18 (largely sand) sink to the base of the vessel, and are withdrawn 19 therefrom as an underflow stream termed primary tailings. A
major portion of the bitumen, present in the form of suspended 21/ globules, films over entrained air bubbles and rises to form 22 primary bitumen froth which is recovered.
23 A middlings stream comprising less floatable bitumen 24 together with clay particles forms between the settled solids and floating froth layers. The middlings stream is withdrawn from 26 the PSV and subjected to secondary flotation in sub-aerated cells 27 to produce secondary bitumen froth and a tailings stream which 28 contains water, solids and a small amount of bitumen.
~13'0~ 13 l The fro~h streams are combined and subjected to 2 centrifugal ~eparation to yield pure bitumen and a tailings 3 stream. Again, this tailings stream comprises water, solids and 4 bitumen.
The three tailings streams are then combined and 6 discharged into a tailings pond.
7 The combin~d tailings stream thus comprises coarse sand 8 grains, fine clay particles (referred to as fines), water, and g some bitumen. By fines is meant those particles having an average size less than forty microns.
11 The tailings pond, typically, has a depth of 12 approximately 125-150 feet. Upon discharge of a combine~
13 tailings stream into ~he pond, a~er what is re~erred to as the 14 first sedimentation stage, the stream settles into an uppex layer of clarified water oP about 15 fe0t in depth, a sludge layer of 16 about 60 feet in depth and a lower layer of dirty water.
17 Typically, the upper layer of clarified water is recycled to the ~8 plant. The lower sludge plus water layer is considered to be in, 19 what is termed, a steady~state pseudo-stabilized condition.
Hereinafter, the term 'sludge' will refer to these two layers in 21 the pseudo-stabilized state. Without being bound by same, it is 22 believed that it is the presence of fines which deletiorously 23 stabilizes the sludge layer thereby preventing normal settling of 24 the solids.
The properties of sludge are outlined in further detail 26 in a paper entitled ~Behaviour of Oil S~nd Tailings Sludge~ by J.
27 T. Scott et. al., published by the Petroleum Society of CIM in 28 Paper No. 82-33-85.
29 The prior art patents describe numerous se~i -ntation ~'~r~ 3 1proces~es~ exemplary patents being Canadian Patent 1,247,550, 2U~S. 4,783,268, and Canadian Patent 1,236,419.
3It is an objective of the present inven-tion to separate 4and remova the ~ines and residual bitumen from the sludge thereby 5permitting the r~ ~ining solids to settle and as a result recover 6improved yields of recycle water.
7SUMMARY OF THE IN~NllON
8The present invention is based on the discovery that a 9cationic surfactant is preferentially adsorbed by the fines in 10the sludge. When the sludge is aerated and diluted, the fines 11together with the residual bitumen are flocculated, and can be 12floatad off and removed. In the absence of a surfactant, the 13residual bikumen .- ~;n~ in the sludge.
1~In accordance with the present inven~ion there is 15provided a process for treating sludge in the tailings pond of a 16plant using the hot water extraction process to extract bitumen 17from oil sands. The process involves first adding a 18predetermined quantity of a cationic surfactant to said sludge.
19The mixture is agitated for a sufficient period of time for the 20surfactant to preferentially contact the fines.
21The cationic surfactant may be selected from alkyl 22amines or alkyl derivatives of ammonia and fatty acids.
23The quantity of surfactant would range between about 24100 g/tonne to about 1,000 g/tonne.
25The mixture is then aerated to flocculate and float 26said fines. A fraction of the flocculated fines is removed. As 27a result the rate of sedimentation of said sludge is accelerated.
28In a broad aspect, the invention relates to a process 1 -for treating a ~ines~con-taining sluclge in -the tailings pond of a 2 plant which uses the ho~ water process used for extracting 3 bitumen from oil sand which comprises:
4 adding a predetermined quantity of a cationic surfactant to said sludge;
retAining said mixture under agitation for a suf~icient 7 period of time to permit said surfactant to contact said fines;
8 aerating said mixture to -flocculate and float said g fines;
diluting said mixture; and 11 removing a fraction of said floccula~ed fines and 12 residual bitumen to thereby accelerate the rate of sedimentation 13 of said sludge.
Figure 1 is a plot of the rate of sedimentation of 16 fines versus time.
17 Figure 2 is an illustrative representation showing 18 settling of treated ~ludge with various quantities of surfackant 19 and untreated sludge.
Figure 3 is a schematic showing a plant process.
22 Having reference ~o the accompanying figures, there is 23 provided a process for accelerating the rate of sedimentation of 24 a sludge found in the tailings pond of a plant using the hot water process for the extraction of bitumen from oil sands.
26 The schematic for the process for a plant producing 27 20,700 b/d bitumen is illustrated in Figure 3.
~~3 ExpERIMENTAL
2 The following laboratory ~est work is included to 3 clemonstrate the operability of the present invention.
4 The measure o~ sedimentation rate of the sludge was assessed using the standard sedimentation kest of Coe and 6 Clerenger wherein the position of the interface with settling 7 time is used as an indicia of settling rate.
8 A standard dressinq test appara~ls ~WEMCO Flotation 9 Cell) was used for processing the sludge prior to the ~atch-settling test. A specimen of untreated sludge (A) was kept as a 11 control. No chan~e in the behaviour of the sludge or interface 12 separation was observed.
13 More speci;Eically, 500 cc of sludge was introciuced into 1~ the flotation cell. 3500 cc of tap water was added to dilute the mixture. 0.065 g of d.iamine (supplied by AICZO Chemicals Ltd. CES
16 109), was added to the cell. The mixtuxe was mixed for about 5 17 minutes to allow time for the surfactant to contact the solids.
18 The pH was adjusted to about 8.2. The mixture was then aerated 19 in the flota-tion apparatus and the froth collected for 5 minutes.
3500 cc of tap water was added to dilute the mixture. The 21 flocculated fines were floated and the resultant froth was 22 removed from the mixture. 450 cc of the froth was ~ransferred to 23 a 500 cc glass, graduated cylinder. The evolution of the 24 interface i.e. settling was observed for approximately 1000 minutes. The results are illustrated in ~igure 2.
2~ B represents addition of 200 g of diamine/tonne of 27 solids contained in the sludge; C represents addition of 300 g of 28 diamine/tonne of solids contained in the sludge; D represents 29 addition of 475 g of diamine/tonne of solids contained in the sludge and E shows the effec-t of addi-tion of 700 g of 2 diamine/tonne of solids con~ained in the sludge.
S BACKGROUND OE' THE INVEN~ION
6 In the Athabasca region of Albe.rta, C~n~a, geological 7 depositions of oil sand occur. T~e:re are ln commercial 8 opera~ion, two plan~s which use the hot water extraction process g for extracting bitumen from the oil sand. The hot water extraction process has been well detailed in both publications 11 and patents.
12 Briefly, the first step of the hot water process 13 involves conditioning the oil sand by mixing the mined. oil sand 14 with hot water and sodium hydroxide in a rotating drum to form a slurry~ The slurry is then screened and diluted with additional 16 hot water prior to being pumped into a flotation/settling vessel.
17 In this vessel, re~erred to as the PSVI most of the solids 18 (largely sand) sink to the base of the vessel, and are withdrawn 19 therefrom as an underflow stream termed primary tailings. A
major portion of the bitumen, present in the form of suspended 21/ globules, films over entrained air bubbles and rises to form 22 primary bitumen froth which is recovered.
23 A middlings stream comprising less floatable bitumen 24 together with clay particles forms between the settled solids and floating froth layers. The middlings stream is withdrawn from 26 the PSV and subjected to secondary flotation in sub-aerated cells 27 to produce secondary bitumen froth and a tailings stream which 28 contains water, solids and a small amount of bitumen.
~13'0~ 13 l The fro~h streams are combined and subjected to 2 centrifugal ~eparation to yield pure bitumen and a tailings 3 stream. Again, this tailings stream comprises water, solids and 4 bitumen.
The three tailings streams are then combined and 6 discharged into a tailings pond.
7 The combin~d tailings stream thus comprises coarse sand 8 grains, fine clay particles (referred to as fines), water, and g some bitumen. By fines is meant those particles having an average size less than forty microns.
11 The tailings pond, typically, has a depth of 12 approximately 125-150 feet. Upon discharge of a combine~
13 tailings stream into ~he pond, a~er what is re~erred to as the 14 first sedimentation stage, the stream settles into an uppex layer of clarified water oP about 15 fe0t in depth, a sludge layer of 16 about 60 feet in depth and a lower layer of dirty water.
17 Typically, the upper layer of clarified water is recycled to the ~8 plant. The lower sludge plus water layer is considered to be in, 19 what is termed, a steady~state pseudo-stabilized condition.
Hereinafter, the term 'sludge' will refer to these two layers in 21 the pseudo-stabilized state. Without being bound by same, it is 22 believed that it is the presence of fines which deletiorously 23 stabilizes the sludge layer thereby preventing normal settling of 24 the solids.
The properties of sludge are outlined in further detail 26 in a paper entitled ~Behaviour of Oil S~nd Tailings Sludge~ by J.
27 T. Scott et. al., published by the Petroleum Society of CIM in 28 Paper No. 82-33-85.
29 The prior art patents describe numerous se~i -ntation ~'~r~ 3 1proces~es~ exemplary patents being Canadian Patent 1,247,550, 2U~S. 4,783,268, and Canadian Patent 1,236,419.
3It is an objective of the present inven-tion to separate 4and remova the ~ines and residual bitumen from the sludge thereby 5permitting the r~ ~ining solids to settle and as a result recover 6improved yields of recycle water.
7SUMMARY OF THE IN~NllON
8The present invention is based on the discovery that a 9cationic surfactant is preferentially adsorbed by the fines in 10the sludge. When the sludge is aerated and diluted, the fines 11together with the residual bitumen are flocculated, and can be 12floatad off and removed. In the absence of a surfactant, the 13residual bikumen .- ~;n~ in the sludge.
1~In accordance with the present inven~ion there is 15provided a process for treating sludge in the tailings pond of a 16plant using the hot water extraction process to extract bitumen 17from oil sands. The process involves first adding a 18predetermined quantity of a cationic surfactant to said sludge.
19The mixture is agitated for a sufficient period of time for the 20surfactant to preferentially contact the fines.
21The cationic surfactant may be selected from alkyl 22amines or alkyl derivatives of ammonia and fatty acids.
23The quantity of surfactant would range between about 24100 g/tonne to about 1,000 g/tonne.
25The mixture is then aerated to flocculate and float 26said fines. A fraction of the flocculated fines is removed. As 27a result the rate of sedimentation of said sludge is accelerated.
28In a broad aspect, the invention relates to a process 1 -for treating a ~ines~con-taining sluclge in -the tailings pond of a 2 plant which uses the ho~ water process used for extracting 3 bitumen from oil sand which comprises:
4 adding a predetermined quantity of a cationic surfactant to said sludge;
retAining said mixture under agitation for a suf~icient 7 period of time to permit said surfactant to contact said fines;
8 aerating said mixture to -flocculate and float said g fines;
diluting said mixture; and 11 removing a fraction of said floccula~ed fines and 12 residual bitumen to thereby accelerate the rate of sedimentation 13 of said sludge.
Figure 1 is a plot of the rate of sedimentation of 16 fines versus time.
17 Figure 2 is an illustrative representation showing 18 settling of treated ~ludge with various quantities of surfackant 19 and untreated sludge.
Figure 3 is a schematic showing a plant process.
22 Having reference ~o the accompanying figures, there is 23 provided a process for accelerating the rate of sedimentation of 24 a sludge found in the tailings pond of a plant using the hot water process for the extraction of bitumen from oil sands.
26 The schematic for the process for a plant producing 27 20,700 b/d bitumen is illustrated in Figure 3.
~~3 ExpERIMENTAL
2 The following laboratory ~est work is included to 3 clemonstrate the operability of the present invention.
4 The measure o~ sedimentation rate of the sludge was assessed using the standard sedimentation kest of Coe and 6 Clerenger wherein the position of the interface with settling 7 time is used as an indicia of settling rate.
8 A standard dressinq test appara~ls ~WEMCO Flotation 9 Cell) was used for processing the sludge prior to the ~atch-settling test. A specimen of untreated sludge (A) was kept as a 11 control. No chan~e in the behaviour of the sludge or interface 12 separation was observed.
13 More speci;Eically, 500 cc of sludge was introciuced into 1~ the flotation cell. 3500 cc of tap water was added to dilute the mixture. 0.065 g of d.iamine (supplied by AICZO Chemicals Ltd. CES
16 109), was added to the cell. The mixtuxe was mixed for about 5 17 minutes to allow time for the surfactant to contact the solids.
18 The pH was adjusted to about 8.2. The mixture was then aerated 19 in the flota-tion apparatus and the froth collected for 5 minutes.
3500 cc of tap water was added to dilute the mixture. The 21 flocculated fines were floated and the resultant froth was 22 removed from the mixture. 450 cc of the froth was ~ransferred to 23 a 500 cc glass, graduated cylinder. The evolution of the 24 interface i.e. settling was observed for approximately 1000 minutes. The results are illustrated in ~igure 2.
2~ B represents addition of 200 g of diamine/tonne of 27 solids contained in the sludge; C represents addition of 300 g of 28 diamine/tonne of solids contained in the sludge; D represents 29 addition of 475 g of diamine/tonne of solids contained in the sludge and E shows the effec-t of addi-tion of 700 g of 2 diamine/tonne of solids con~ained in the sludge.
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for treating a fines-containing sludge in the tailings pond of a plant which uses the hot water process for extracting bitumen from oil sand which comprises:
adding a predetermined quantity of a cationic surfactant to said sludge;
retaining said mixture under agitation for a sufficient period of time to permit said surfactant to contact said fines;
aerating said mixture to flocculate and float said fines;
diluting said mixture; and removing a fraction of said flocculated fines and residual bitumen to thereby accelerate the rate of sedimentation of said sludge.
adding a predetermined quantity of a cationic surfactant to said sludge;
retaining said mixture under agitation for a sufficient period of time to permit said surfactant to contact said fines;
aerating said mixture to flocculate and float said fines;
diluting said mixture; and removing a fraction of said flocculated fines and residual bitumen to thereby accelerate the rate of sedimentation of said sludge.
2. The process as set forth in claim 1 wherein said cationic surfactant comprises a monopolar, ionizable compound selected from an alkyl amine or an alkyl derivative of ammonia and a fatty acid.
3. The process as set forth in claim 2 wherein the quantity of said surfactant ranges from between about 100 g/tonne to about 1,000 g/tonne.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2006483 CA2006483C (en) | 1989-12-20 | 1989-12-20 | Accelerated sedimentation of sludge |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2006483 CA2006483C (en) | 1989-12-20 | 1989-12-20 | Accelerated sedimentation of sludge |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2006483A1 CA2006483A1 (en) | 1991-06-20 |
| CA2006483C true CA2006483C (en) | 1999-01-19 |
Family
ID=4143869
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2006483 Expired - Fee Related CA2006483C (en) | 1989-12-20 | 1989-12-20 | Accelerated sedimentation of sludge |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2006483C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104271212A (en) * | 2012-02-02 | 2015-01-07 | 绿色能源有限公司 | Methods for recovering and/or removing reagents from porous media |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011032253A1 (en) | 2009-09-15 | 2011-03-24 | Suncor Energy Inc. | Process for drying oil sand mature fine tailings |
| CA2936031C (en) | 2009-09-15 | 2019-09-03 | Adrian Peter Revington | Techniques for flocculating and dewatering fine tailings |
| AU2009354586A1 (en) | 2009-10-30 | 2012-05-24 | Suncor Energy Inc. | Depositing and farming methods for drying oil sand mature fine tailings |
-
1989
- 1989-12-20 CA CA 2006483 patent/CA2006483C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104271212A (en) * | 2012-02-02 | 2015-01-07 | 绿色能源有限公司 | Methods for recovering and/or removing reagents from porous media |
| CN104271212B (en) * | 2012-02-02 | 2017-03-29 | 绿色能源有限公司 | For the method for reclaiming from permeability medium and/or remove reagent |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2006483A1 (en) | 1991-06-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |