CA2004352C - Hot water extraction process and apparatus - Google Patents
Hot water extraction process and apparatusInfo
- Publication number
- CA2004352C CA2004352C CA 2004352 CA2004352A CA2004352C CA 2004352 C CA2004352 C CA 2004352C CA 2004352 CA2004352 CA 2004352 CA 2004352 A CA2004352 A CA 2004352A CA 2004352 C CA2004352 C CA 2004352C
- Authority
- CA
- Canada
- Prior art keywords
- slurry
- bitumen
- separation
- vessel
- froth
- 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 - Lifetime
Links
- 238000000034 method Methods 0.000 title claims abstract description 56
- 238000003809 water extraction Methods 0.000 title description 4
- 239000010426 asphalt Substances 0.000 claims abstract description 88
- 238000000926 separation method Methods 0.000 claims abstract description 82
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 53
- 239000002002 slurry Substances 0.000 claims abstract description 50
- 230000003750 conditioning effect Effects 0.000 claims abstract description 33
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 32
- 239000007787 solid Substances 0.000 claims abstract description 32
- 238000011084 recovery Methods 0.000 claims abstract description 24
- WVYWICLMDOOCFB-UHFFFAOYSA-N 4-methyl-2-pentanol Chemical compound CC(C)CC(C)O WVYWICLMDOOCFB-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000003350 kerosene Substances 0.000 claims abstract description 13
- 239000004576 sand Substances 0.000 claims abstract description 13
- 230000001143 conditioned effect Effects 0.000 claims abstract description 11
- 230000005484 gravity Effects 0.000 claims abstract description 10
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 239000006185 dispersion Substances 0.000 claims description 3
- 238000009291 froth flotation Methods 0.000 claims description 2
- 238000005086 pumping Methods 0.000 claims description 2
- 239000003518 caustics Substances 0.000 description 23
- 239000010802 sludge Substances 0.000 description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 238000005188 flotation Methods 0.000 description 8
- 239000000126 substance Substances 0.000 description 8
- 239000004927 clay Substances 0.000 description 7
- 239000012071 phase Substances 0.000 description 7
- 238000000605 extraction Methods 0.000 description 5
- 239000003027 oil sand Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 238000005065 mining Methods 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- 239000000080 wetting agent Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- YNPNZTXNASCQKK-UHFFFAOYSA-N Phenanthrene Natural products C1=CC=C2C3=CC=CC=C3C=CC2=C1 YNPNZTXNASCQKK-UHFFFAOYSA-N 0.000 description 1
- DGEZNRSVGBDHLK-UHFFFAOYSA-N [1,10]phenanthroline Chemical compound C1=CN=C2C3=NC=CC=C3C=CC2=C1 DGEZNRSVGBDHLK-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000002283 diesel fuel Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000009533 lab test Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 235000010755 mineral Nutrition 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 235000017550 sodium carbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000007790 solid phase Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/02—General arrangement of separating plant, e.g. flow sheets specially adapted for oil-sand, oil-chalk, oil-shales, ozokerite, bitumen, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/02—Froth-flotation processes
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/04—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by extraction
- C10G1/047—Hot water or cold water extraction processes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03D—FLOTATION; DIFFERENTIAL SEDIMENTATION
- B03D1/00—Flotation
- B03D1/14—Flotation machines
- B03D1/1406—Flotation machines with special arrangement of a plurality of flotation cells, e.g. positioning a flotation cell inside another
Landscapes
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Geology (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Extraction Or Liquid Replacement (AREA)
Abstract
A process for the separation and recovery of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises the steps of slurrying 30 to 70% by weight oil sands in water, heating said slurry to a temperature in the range of about to about 90°C, adding an effective amount of conditioning agents and air to said slurry and intimately admixing said conditioning agents and air with the slurry, preferably in a pipeline, feeding said conditioned and aerated slurry into said separation vessel and recovering bitumen as a froth. The conditioned and aerated slurry is introduced underwater into the separation vessel in a froth flotation-gravity separation zone wherein bitumen floats to the surface as a froth and coarse solids and a portion of fines fall by gravity to a bottom discharge portion of the vessel. The conditioning agents have the characteristics of kerosene and methyl-isobutyl-carbinol in an effective amount in the range of about 200 to 400 ppm and said kerosene and methyl-isobutyl-carbinol are present in the ratio of about 2:1. The separation vessel has a froth flotation-gravity separation zone and a quiescent zone adjacent thereto with at least one cone bottom for collecting and removing sand and fine solids.
Description
Z0()4352 .
~ACKGROUND OF THE INVENTION
This invention relates to a process and apparatus for the separation of bitumen from oil sands and, more particularly, relates to an enhanced process and apparatus for the separation and recovery of bitumen from oil sands using a hot water process.
One method for recovering bitumen from oil sands, such as the Athabasca oil sands mined in Alberta, Canada, i8 known as the Clark hot water process. In this process, the oil sands feed mined by bucket wheels, draglines, shovels and the like is transported via conveyor belts from a mining face to an extraction plant. The oil sands feed is then digested in a rotating tumbler with hot water and caustic lNaOH) is added to assist separation of the bitumen from the sands by flotation using specific gravity differential between bitumen and water and solids while the residual mineral matter is gravity separated and discarded or further treated for serondary recovery of bitumen.
It has been found that the separation technique in the Clark hot water process utilizing caustic results in a stream of fine tailings that require a period of time as long as several months for partial settling of the fines and as long as 3 to 5 years to reach a 30~ by weight solids mature sludge. The resulting sludge still is unable to support the weight of tailings above it, thus necessitating large tailings ponds as the sludge accumulates.
The caustic used in the Clark hot water process also changes the properties of the bitumen froth product and makes it difficult to purify to the desired level of pipeline crude. For example, caustic addition changes the dielectric properties of bitumen and makes it difficult to purify the bitumen by the electrostatic coalescence method.
Another method of recovering bitumen from oil sands involves the transportation and treatment of an aqueous 2004~5X
.
slurry of the oil sands feed in cold water, i.e. ambient temperature, as described in co-pending Canadian Patent Applicatlon Serial No. 563,190, filed March 31, 1988.
While this approach reduces the cost of the conveyor transportation when using pipeline transportation and obviates the heating of the water, the separation process requires the input of mechanical shear to liberate the bitumen and to compensate for the lack of heat. While conditioning agents are used in this process, the slurry has to be subjected to an equivalent of high shear mixing in order to ensure satisfactory bitumen recovery.
U.S. Patent No. 4,425,227 issued January 20, 1984 discloses an ambient froth flotation process for the recovery of bitumen from oil sands in which oil sands are milled with water, having collector selected from light hydrocarbon oil in an amount in the range of 0.13 to 1.4 by weight based on raw oil sands feed together with a dispersing/wetting agent such as soda ash and sodium hydroxide generated by addition of hydrated lime to tailings for use in the recycle water. Excessive and costly quantities of collectors and dispersing/wetting agents are used in this process which can adversely affect subsequent settling and disposal of tailings fines.
It is an object of the present invention to provide a process for separating and recovering bitumen from oil sands by the hot water process in which reduced and cost effective quantities of conditioning agents are used.
It is another object of the present invention to provide a process for separating and recovering bitumen from oil sands in which the tailings, particularly the fines portion, settle rapidly into a geotechnically stable mass to free water from the fines for recycle purposes or discharge and to substantially reduce the size of tailings 200~
ponds. The settled fines are geotechnically competent and can support additional layering of coarse sand thereon to improve tailings management by the ability to accumulate alternate layers of coarse and fine solids.
It is a further object of the present invention to provide an improved process and an apparatus for concurrent froth flotation-gravity separation of bitumen from coarse and fine solids in the oil sands.
SUMMARY OF THE INVENTION
It has been found that the substitution of conditioning agents having the characteristic~ of kerosene (Rl and methyl-isobutyl-carbinol ~MIBC) in place of the caustic used in the conventional hot-water process, usually sodium hydroxide (NaOHI, surprisingly enhances bitumen separation in a hot water process and improves the settling characteristics of the sand and fines tailings. More particularly, it has been found that the addition of kerosene and MIBC in a ratio of about 2:1, added in an amount of about 200 to 400 parts per million (ppm) with an effective amount of air to an oil sands slurry for intimate mlxing prior to discharge underwater lnto a separation vessel provides effective separation of bitumen from solids while imparting improved settling characteristrics to coarse and fine solids in a hot water separation process.
The conditioned and aerated slurry is discharged under water into a separation vessel wherein aerated bitumen rises to the surface as froth while coarse solids and a portion of fines sink by gravity to a bottom discharge portion of the vessel. R~ -ini~g bitumen and fines flow to a quiescent zone for continued separation of bitumen, which rises to surface as froth, from the fines which fall by gravity to a bottom discharge.
The efficient separation of bitumen from the , 20~4,~5;~
aerated feed slurry for optimum bitumen recovery is achieved with a novel discharge mechanlsm which provides fine air bubbles to form a stable bituminous product.
According to the present invention, there i8 thus provided a process for the separation and recovery of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises slurrying 30 to 70~ by weight oil sands in water, either in a tumbler as known in the Clark hot water process or in a pipeline of predetermined length, heating said slurry to a temperature in the range of about 30 to about 90oC, preferably about 800C, adding an effective amount of conditioning agents and air to said slurry, and intimately ~-~ ixing said conditioning agents and air with the slurry prior to feedlng conditioned and aerated slurry into said separation vessel, and recovering bitumen as a froth.
In accordance with another aspect of the invention, there is provided a process for the separation of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises slurrying 30 to 70~ by weight oil sands in water, heating said slurry to a temperature in the range of about 30 to about 90oC, preferably about 800C, pumping said slurry through a pipeline to the separation vessel, adding to the slurry in the pipeline an effective amount of conditioning agents and air prior to feeding said slurry into the said separation vessel for intimate admixture of the conditioning agents and air with the slurry, and feeding said conditioned and aerated slurry underwater into the separation vessel in a froth flotation-gravity separation zone wherein bitumen floats to the surface as a froth and coarse solids and a portion of fines fall by gravity to a bottom discharge portion of the vessel.
20~4;~}5;~
f ' ' - The conditioning agents have the characteristics of kerosene/MIBC, preferably in a ratio of about 2:1, added in a total amount of about 200 to 400 ppm of the oil sands slurry.
BRIEF DESCRIPTION OF THE DRAWINGS
The process and apparatus of the invention will now be described with reference to the accompanying drawings, in which:
Figure 1 is a schematic flowsheet and apparatus showing the process of the present invention;
Figure 2 is a schematic flowsheet and apparatus showing another embodiment of the apparatus of the present application;
Figure 3 is a graph showing bitumen recovery relative to conditioning agent concentration in hot water separation processes conducted at 800C in accordance with the present invention compared to the conventional hot water process using caustic;
Figure 4 is a graph showing bitumen recovery relative to conditioning agent concentration at various temperatures;
Figure 5 is a graph showing settling rates of tailing fines from the process of the present invention compared to settling rates of tailing fines from the conventional hot water process.
and;
Figure 6 is a perspective view of a discharge ~ -mechanism of the present invention.
Zo~4~S;~
DESCRIPTION OF THE PREF~RRED EMBODIMENTS
With reference now to Figure l, Figure 1 is a schematic flow diagram showing the preferred embodiment of the method and apparatus of the present invention in which oil sands mined by conventional dry mining or by dredging, indicated by numeral 10, are slurried with water and pumped by pump 12 through pipeline 14 to separation vessel 16.
The slurry can be heated by the injection of steam 18 before or after pump 12 and conditioning agents 22 and air 24 injected into pipeline 14 sufficiently upstream from the separation vessel 16 to permit intimate admisture of the conditioning agents and air with the slurry.
The conditioned and aerated slurry is introduced underwater into a horizontally elongated separation vessel 16 in a froth flotation-gravity separation zone 26 wherein the aerated bitumen rises to the surface as a bitumen froth 28 while the coarse solids and a portion of fines sink to the discharge portion of the vessel 30 as tailings 32. The r~ -ini~g fine solids and r~ g~ining bitumen that did not attach to air bubbles, are moved horizontally along the vessel shown in Figure 1 to a quiescent zone 34 in which a substantial portion of r= sin~ng bitumen rises to the surface to join the froth 28. A substantial portion of r.~ ning fine solids fall by gravity to the bottom of separation vessel 16 to be raked into discharge portion 30, preferably having a cone configuration for collection and discharge from the vessel. Instead of rakes, the bottom of the quiescent zone may have a plurality of cone configurations depicted by broken lines 31 for discharge to tailings. A continuously moving froth skimmer moves the bitumen froth to the discharge end 38 of vessel 16 for discharge over weir 40 while the tailings solids are discharged to a tailings pond 42 or to a similar 20~4~
-separatlon vessel 44 for secondary bitumen recovery in the same manner as discussed hereinabove with reference to the separation in separation vessel 16.
The apparatus of the present invention combines the features of both pneumatic flotation and gravity separation in a single unit operation wherein two opposing phen~ _na occur, namely aerated bitumen particles rise to the surface at a known velocity in an opposite direction from liberated sand particles which tend to settle under gravity at relatively fast velocities. The introduction of the conditioned and aerated slurry into the separation vessel below the surface of the froth flotation-gravity separation zone in1 izes trapping or drawing of bitumen particles into the settling solids stream to become entrapped in the tailings. The cone bottom discharge portion of the vessel allows the collection and separation of solids while the elongated upper portion of the separation vessel extending from the froth flotation-gravity separation zone 26 to a quiescent zone 34 provides sufficient residence time for the bitumen to rise to the surface and to be collected in the bitumen froth 28.
Figure 2 illustrates schematically another embodiment of the present invention as applied to the separation stages of the Clark hot water process in which the separation vessel 50 contains a froth flotation-gravity separation zone 52 to which conditioned and aerated oil sands slurry i8 introduced below the surface thereof for separation of bitumen from the oil sands in the manner described hereinabove in zone 26 of vessel 16. Bitumen froth 54 is discharged as a product stream 56 while bitumen in the middlings is discharged by line 58 to flotation vessel 60 for further recovery of bitumen as a concentrate 62 to be added to product stream 56 while the -tailings from separation vessel 50 are fed to secondary recovery vessel 64. The feed of middlings 58 to flotation vessel 60 and feed of tailings 63 to secondary separation vessel 64 are introduced below the surface of the vessels. Tailings from flotation vessel 60 and from secondary vessel 64 are discharged to a tailings pond 42.
Figure 6 illustrates a discharge dispersion apparatus 70 secured to the end of pipeline 14 and disposed below the surface 72 of the bitumen froth within froth flotation-gravity separation zone 26 of vessel 16.
Apparatus 70 comprises an outer cone 74 concentric with inner cone 76 defining a conlcal annulus 78 of uniform width therebetween and open-ended at 80. A plurality of openings 82 are formed on outer cone 74 for the unlform dispersion of small air bubbles from openings 82 and from annular openings at 80 into zone 26 for production of a stable bitumen froth.
The conventional Clark hot water process in which bitumen from the oil sands is floated as a froth from coarse sand and fines at a temperature of about 80OC
utilizes caustic, as has been discussed, for conditioning the oil sands prior to separation of bitumen from the sands. With reference to Figure 3, it is shown that optimum recovery of bitumen is attained at about 1100 ppm of caustic, as is well known for this prior art process.
In accordance with the process of the present invention, optimum recovery of bitumen is attained at a concentration of conditioning agents comprises of kerosene and MIB0 in the range of about 200-400 ppm for an ore having 9.5% by weight bitumen and 23~ by weight fines, for a substantial savings in the cost of said conditioning agents compared to the use of caustic. Although it is understood that theoretical considerations are not binding, . t Z~
it is believed that the kersosene acts as a collector by increasing the hydrophobicity of the liberated bitumen and that the-MIBC acts as a frother to increase the affinity of bitumen to air bubbles. Although the description proceeds with reference to kerosene as a collector, it will be understood that other collectors having the characteristics of kerosene such as diesel fuel, No. 2 burner oil and the like may be satisfactory as a collector. In like manner, other frothers having the characteristics of MIBC may be used.
A ratio of K:MIBC of about 2:1 was found to provide optimum conditioning of the bitumen.
The process of the invention and its utility will now be discussed with reference to the following non-limitative examples.
Batch test extractions were employed to simulate the hot water extraction process. The extraction unit is a modified Denver(IM) flotation cell, operated at 10 to 13 rev/s to provide mixing for slurrying oil sand with hot water in a water jacketed stainless steel pot. The oil sand slurry was maintained at a desired temperature by circulating hot water from the water bath through the jacket of the pot.
A published procedure for the laboratory test on the hot water bitumen extraction from oil sand and its test conditions in accordance with the paper by Sanford, E.C.
and Seyer, F.A. entitled "Processibility of Athabasca Tar Sand Using a Batch Extraction Unit: The Role of NaOH", CIM
Bulletin, March 1979 was closely followed in this study.
The test procedure involves four distinct steps.
The pot is charged with 500 grams of oil sand lumps and 150 mL of hot water, the desired slurry temperature is 20~
` : !
established, and the charges are slurried at an impeller speed of 10 rev/s for 10 minutes with air aeration at 7 mL/s at the same time. This step simulates oil sand slurrying in the tumblers in the continuous process. An additional 1000 mL of hot flood water is then added at the end of 10 minutes. This step approximates the separation process in the primary vessels. The mixing is then continued at the same speed for another 10 minutes without aeration before the floated bitumen is s~i ^d. The slurry next is subjected to another 5 minutes of mixing at 13 rev/s while air is injected at approximatrely 3.9 mL/s to simulate secondary recovery. At the end of the run, product froth is collected in the same manner as secondary froth. Finally, the r ~ der in the pot is drained and analyzed for residual bitumen not recovered by the process.
For the bitumen recovery test run, tailings, primary and secondary froth samples are weighed and sent for bitumen/water/solids analyses. The analytical data are used for establishing material balance and bitumen recovery.
For the sludge settling data run, the tailings sample, after the removal of coarse sands, is allowed to settle in a lL graduated cylinder. The position of the interface between sludge and clear water is recorded with time. At the end of 10 days settling time, the sludge layer is separated from the clear water layer and analyzed for solids content or density.
A batch of oil sands sample was analyzed and the sample is shown in the following table.
- 10 ~
20~)4;~;2 - Table 1 Wt ~ Bitumen 9.5 Wt~ Water 3.5 'Wt~ Solids 87.0 Wt~ Fines in solids 22.6 As shown in Figure 3, the results of the tests using the conditioning agents of the present invention indicate that recovery increased steadily with increasing chemical level, varying from 65~ with no chemical addition to 93.8~ with 200 ppm chemicals addition. Beyond the 200 ppm level, recovery dropped slightly due to the chemical overdosing. The ratio of the collector chemical ~K~ to the frother chemical ~MI was maintained at the value of 2:1 for these tests. While the addition of the collector chemical ~K~ was meant to increase the hydrophobicity of the liberated bitumen, the addition of the frother chemical ~M) was used to improve the affinity of bitumen to air bubbles.
The test data as shown in Figure 3 indicate that addition of the two chenmicals to the the slurry significantly increased the bitumen recovery in the separation steps.
Tests using caustic addition also d~ -nstrated similar behavior, but the trend showing higher bitumen recovery with increases in caustic addition rate occurred only at much higher dosages, i.e. in the range between 400 and 1,100 ppm. The recovery ultimately reached over 90 when 1,100 ppm of caustic was added.
Tests were conducted to investigate the effectiveness of adding the conditioning agents of the invention and caustic at lower temperatures, i.e. 50 and 30OC. Results of these tests are shown in Figure 4 together with the 80OC test data. At the reduced temperatures, bitumen liberation is low, reflecting a low 20~4~i2 t--bitumen recovery obtained using both addition ofconditioning agents according to the present invention and addition of caustic.
It was found that tailings produced from the process using the conditioning agent of the invention settle rapidly and do not form a stable sludge. The tailings water clarify within in several days and can be reused. In comparison, tailings produced from the hot water extraction process using caustic settle slowly and usually take years to become a mature sludge (containing about 35~ solids).
To investigate the settling characteristics of the fines portion of the tailings obtained from the hot water extraction process using the conditioning agents of the invention and caustic, four tests were performed at 800C
using the above-described sample. Two of the tests were conducted by adding 1,100 ppm of caustic, and the other two by adding 200 ppm K:MIBCin the ratio of 2:1. The tailings consist of coarse sand, clay fines, water and a trace of bitumen ( 0.5~). The procedure which was generally followed comprised settling the coarse sand from the taillng slurry immediately following the bitumen separation steps as described above. The tailing water and clay fines were decanted into a one liter capacity graduated cylinder and allowed to settle for about a week to 10 days. In the case of the tailings produced according to the present invention, settling of the fines occurred as soon as the slurry established a quiescent state in the graduated cylinder, and two distinct layers were observed: (1) a loosely compacted layer of clay fines at the bottom of the graduated cylinder, and (2) a clear water phase on top of the clay sludge. The water phase appeared to be slightly 20~4~Ej2 murky initially, but began to clarify in about 15 minutes.
Later, the top water phase increased in volume as water from the solid phases continuously migrated upwardly to the clear water phase, thus increasing the density of the sludge phase. The location of the interface between the clear water layer and the sludge layer was recorded at various times throughout the test. At the end of the settling test? the supernatant liquid was separated from the sediment and the sediment was removed and oven dried to determine the amount of solids in the sludge.
The solid weight and the interface locations recorded during the tests provided the time variations of the tailing sludge density, which are shown in a semi-log plot in Figure 5. The tailing sludges from the two tests according to the present invention increased in density quite rapidly, reaching a pulp density of about 27% solids in about 5 days from the initial 6-7% solids content. In contrast, the caustic treated tailings remained practically unchanged at about 4.5% showing little or no fines settling duriing the same period. The above data indicate that the flotation tailings from the process of the present invention would settle much faster than the caustic treated tailings and hence would require less tailings pond area.
Further, a substantial amount of water can be made available for recycle when the conditioning agents of the invention are used in place of caustic in the process.
Tests were also conducted to investigate the strength of the settled fines. The procedure followed for this test was to allow settling of a whole tailings sample produced according to the present invention in a 2-liter graduated cylinder for about a week. Following this period, a portion of the top clear water was siphoned off ~, ~0~4~3æ
and a fresh batch of a simllarly prepared tailings sample was then added on top of the settled bed of fines from the first tailings sample. Another batch of sample was added in a similar fashion a week later. Changes of the interfaces between various layers due to either fines settling or compression from the top layers were noted with time. The bed of the settled sand plu5 clay phases from the first sample appeared to support the second and third batches of tailings samples. The preliminary qualitative data suggest that the tailings produced by the process of the present invention can be layered alternatively between coarse sand and fines clay, and would not create sludge problems such as these experlenced with the caustic dosed tailings. Such a layering phenomenon was not observed in a similar test with the tailings from the caustic hot water process in which the coarse sands from the second tailing sample sank through the clay phase to the bottom.
The present invention provides a number of important advantages. The quantity of conditioning agents required for a hot water process separation of bitumen from oil sands is substantially reduced resulting in the cost savings. The quality of bitumen produced is not adversely affected by the conditioning agents while the settling characteristics of tailings fines are substantially enhanced compared to tailings fines produced by the hot water process using caustic. The conditioning agents and air for further flotation can be introduced and intimately admixed with the slurry in a pipeline before introduction to a separation vessel.
The separation vessel preferably has a froth flotation-gravity separation zone into which the conditioned and aerated slurry is fed below the surface ~- Z0~4352 thereof for effective frothing of the bitumen and a quiescent zone.
It will be understood of course that modifications can be made in the embodiment of the process and apparatus of the invention illustrated and described herewin without departing from the scope and purview of the invention as defined by the appended claims.
~ACKGROUND OF THE INVENTION
This invention relates to a process and apparatus for the separation of bitumen from oil sands and, more particularly, relates to an enhanced process and apparatus for the separation and recovery of bitumen from oil sands using a hot water process.
One method for recovering bitumen from oil sands, such as the Athabasca oil sands mined in Alberta, Canada, i8 known as the Clark hot water process. In this process, the oil sands feed mined by bucket wheels, draglines, shovels and the like is transported via conveyor belts from a mining face to an extraction plant. The oil sands feed is then digested in a rotating tumbler with hot water and caustic lNaOH) is added to assist separation of the bitumen from the sands by flotation using specific gravity differential between bitumen and water and solids while the residual mineral matter is gravity separated and discarded or further treated for serondary recovery of bitumen.
It has been found that the separation technique in the Clark hot water process utilizing caustic results in a stream of fine tailings that require a period of time as long as several months for partial settling of the fines and as long as 3 to 5 years to reach a 30~ by weight solids mature sludge. The resulting sludge still is unable to support the weight of tailings above it, thus necessitating large tailings ponds as the sludge accumulates.
The caustic used in the Clark hot water process also changes the properties of the bitumen froth product and makes it difficult to purify to the desired level of pipeline crude. For example, caustic addition changes the dielectric properties of bitumen and makes it difficult to purify the bitumen by the electrostatic coalescence method.
Another method of recovering bitumen from oil sands involves the transportation and treatment of an aqueous 2004~5X
.
slurry of the oil sands feed in cold water, i.e. ambient temperature, as described in co-pending Canadian Patent Applicatlon Serial No. 563,190, filed March 31, 1988.
While this approach reduces the cost of the conveyor transportation when using pipeline transportation and obviates the heating of the water, the separation process requires the input of mechanical shear to liberate the bitumen and to compensate for the lack of heat. While conditioning agents are used in this process, the slurry has to be subjected to an equivalent of high shear mixing in order to ensure satisfactory bitumen recovery.
U.S. Patent No. 4,425,227 issued January 20, 1984 discloses an ambient froth flotation process for the recovery of bitumen from oil sands in which oil sands are milled with water, having collector selected from light hydrocarbon oil in an amount in the range of 0.13 to 1.4 by weight based on raw oil sands feed together with a dispersing/wetting agent such as soda ash and sodium hydroxide generated by addition of hydrated lime to tailings for use in the recycle water. Excessive and costly quantities of collectors and dispersing/wetting agents are used in this process which can adversely affect subsequent settling and disposal of tailings fines.
It is an object of the present invention to provide a process for separating and recovering bitumen from oil sands by the hot water process in which reduced and cost effective quantities of conditioning agents are used.
It is another object of the present invention to provide a process for separating and recovering bitumen from oil sands in which the tailings, particularly the fines portion, settle rapidly into a geotechnically stable mass to free water from the fines for recycle purposes or discharge and to substantially reduce the size of tailings 200~
ponds. The settled fines are geotechnically competent and can support additional layering of coarse sand thereon to improve tailings management by the ability to accumulate alternate layers of coarse and fine solids.
It is a further object of the present invention to provide an improved process and an apparatus for concurrent froth flotation-gravity separation of bitumen from coarse and fine solids in the oil sands.
SUMMARY OF THE INVENTION
It has been found that the substitution of conditioning agents having the characteristic~ of kerosene (Rl and methyl-isobutyl-carbinol ~MIBC) in place of the caustic used in the conventional hot-water process, usually sodium hydroxide (NaOHI, surprisingly enhances bitumen separation in a hot water process and improves the settling characteristics of the sand and fines tailings. More particularly, it has been found that the addition of kerosene and MIBC in a ratio of about 2:1, added in an amount of about 200 to 400 parts per million (ppm) with an effective amount of air to an oil sands slurry for intimate mlxing prior to discharge underwater lnto a separation vessel provides effective separation of bitumen from solids while imparting improved settling characteristrics to coarse and fine solids in a hot water separation process.
The conditioned and aerated slurry is discharged under water into a separation vessel wherein aerated bitumen rises to the surface as froth while coarse solids and a portion of fines sink by gravity to a bottom discharge portion of the vessel. R~ -ini~g bitumen and fines flow to a quiescent zone for continued separation of bitumen, which rises to surface as froth, from the fines which fall by gravity to a bottom discharge.
The efficient separation of bitumen from the , 20~4,~5;~
aerated feed slurry for optimum bitumen recovery is achieved with a novel discharge mechanlsm which provides fine air bubbles to form a stable bituminous product.
According to the present invention, there i8 thus provided a process for the separation and recovery of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises slurrying 30 to 70~ by weight oil sands in water, either in a tumbler as known in the Clark hot water process or in a pipeline of predetermined length, heating said slurry to a temperature in the range of about 30 to about 90oC, preferably about 800C, adding an effective amount of conditioning agents and air to said slurry, and intimately ~-~ ixing said conditioning agents and air with the slurry prior to feedlng conditioned and aerated slurry into said separation vessel, and recovering bitumen as a froth.
In accordance with another aspect of the invention, there is provided a process for the separation of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises slurrying 30 to 70~ by weight oil sands in water, heating said slurry to a temperature in the range of about 30 to about 90oC, preferably about 800C, pumping said slurry through a pipeline to the separation vessel, adding to the slurry in the pipeline an effective amount of conditioning agents and air prior to feeding said slurry into the said separation vessel for intimate admixture of the conditioning agents and air with the slurry, and feeding said conditioned and aerated slurry underwater into the separation vessel in a froth flotation-gravity separation zone wherein bitumen floats to the surface as a froth and coarse solids and a portion of fines fall by gravity to a bottom discharge portion of the vessel.
20~4;~}5;~
f ' ' - The conditioning agents have the characteristics of kerosene/MIBC, preferably in a ratio of about 2:1, added in a total amount of about 200 to 400 ppm of the oil sands slurry.
BRIEF DESCRIPTION OF THE DRAWINGS
The process and apparatus of the invention will now be described with reference to the accompanying drawings, in which:
Figure 1 is a schematic flowsheet and apparatus showing the process of the present invention;
Figure 2 is a schematic flowsheet and apparatus showing another embodiment of the apparatus of the present application;
Figure 3 is a graph showing bitumen recovery relative to conditioning agent concentration in hot water separation processes conducted at 800C in accordance with the present invention compared to the conventional hot water process using caustic;
Figure 4 is a graph showing bitumen recovery relative to conditioning agent concentration at various temperatures;
Figure 5 is a graph showing settling rates of tailing fines from the process of the present invention compared to settling rates of tailing fines from the conventional hot water process.
and;
Figure 6 is a perspective view of a discharge ~ -mechanism of the present invention.
Zo~4~S;~
DESCRIPTION OF THE PREF~RRED EMBODIMENTS
With reference now to Figure l, Figure 1 is a schematic flow diagram showing the preferred embodiment of the method and apparatus of the present invention in which oil sands mined by conventional dry mining or by dredging, indicated by numeral 10, are slurried with water and pumped by pump 12 through pipeline 14 to separation vessel 16.
The slurry can be heated by the injection of steam 18 before or after pump 12 and conditioning agents 22 and air 24 injected into pipeline 14 sufficiently upstream from the separation vessel 16 to permit intimate admisture of the conditioning agents and air with the slurry.
The conditioned and aerated slurry is introduced underwater into a horizontally elongated separation vessel 16 in a froth flotation-gravity separation zone 26 wherein the aerated bitumen rises to the surface as a bitumen froth 28 while the coarse solids and a portion of fines sink to the discharge portion of the vessel 30 as tailings 32. The r~ -ini~g fine solids and r~ g~ining bitumen that did not attach to air bubbles, are moved horizontally along the vessel shown in Figure 1 to a quiescent zone 34 in which a substantial portion of r= sin~ng bitumen rises to the surface to join the froth 28. A substantial portion of r.~ ning fine solids fall by gravity to the bottom of separation vessel 16 to be raked into discharge portion 30, preferably having a cone configuration for collection and discharge from the vessel. Instead of rakes, the bottom of the quiescent zone may have a plurality of cone configurations depicted by broken lines 31 for discharge to tailings. A continuously moving froth skimmer moves the bitumen froth to the discharge end 38 of vessel 16 for discharge over weir 40 while the tailings solids are discharged to a tailings pond 42 or to a similar 20~4~
-separatlon vessel 44 for secondary bitumen recovery in the same manner as discussed hereinabove with reference to the separation in separation vessel 16.
The apparatus of the present invention combines the features of both pneumatic flotation and gravity separation in a single unit operation wherein two opposing phen~ _na occur, namely aerated bitumen particles rise to the surface at a known velocity in an opposite direction from liberated sand particles which tend to settle under gravity at relatively fast velocities. The introduction of the conditioned and aerated slurry into the separation vessel below the surface of the froth flotation-gravity separation zone in1 izes trapping or drawing of bitumen particles into the settling solids stream to become entrapped in the tailings. The cone bottom discharge portion of the vessel allows the collection and separation of solids while the elongated upper portion of the separation vessel extending from the froth flotation-gravity separation zone 26 to a quiescent zone 34 provides sufficient residence time for the bitumen to rise to the surface and to be collected in the bitumen froth 28.
Figure 2 illustrates schematically another embodiment of the present invention as applied to the separation stages of the Clark hot water process in which the separation vessel 50 contains a froth flotation-gravity separation zone 52 to which conditioned and aerated oil sands slurry i8 introduced below the surface thereof for separation of bitumen from the oil sands in the manner described hereinabove in zone 26 of vessel 16. Bitumen froth 54 is discharged as a product stream 56 while bitumen in the middlings is discharged by line 58 to flotation vessel 60 for further recovery of bitumen as a concentrate 62 to be added to product stream 56 while the -tailings from separation vessel 50 are fed to secondary recovery vessel 64. The feed of middlings 58 to flotation vessel 60 and feed of tailings 63 to secondary separation vessel 64 are introduced below the surface of the vessels. Tailings from flotation vessel 60 and from secondary vessel 64 are discharged to a tailings pond 42.
Figure 6 illustrates a discharge dispersion apparatus 70 secured to the end of pipeline 14 and disposed below the surface 72 of the bitumen froth within froth flotation-gravity separation zone 26 of vessel 16.
Apparatus 70 comprises an outer cone 74 concentric with inner cone 76 defining a conlcal annulus 78 of uniform width therebetween and open-ended at 80. A plurality of openings 82 are formed on outer cone 74 for the unlform dispersion of small air bubbles from openings 82 and from annular openings at 80 into zone 26 for production of a stable bitumen froth.
The conventional Clark hot water process in which bitumen from the oil sands is floated as a froth from coarse sand and fines at a temperature of about 80OC
utilizes caustic, as has been discussed, for conditioning the oil sands prior to separation of bitumen from the sands. With reference to Figure 3, it is shown that optimum recovery of bitumen is attained at about 1100 ppm of caustic, as is well known for this prior art process.
In accordance with the process of the present invention, optimum recovery of bitumen is attained at a concentration of conditioning agents comprises of kerosene and MIB0 in the range of about 200-400 ppm for an ore having 9.5% by weight bitumen and 23~ by weight fines, for a substantial savings in the cost of said conditioning agents compared to the use of caustic. Although it is understood that theoretical considerations are not binding, . t Z~
it is believed that the kersosene acts as a collector by increasing the hydrophobicity of the liberated bitumen and that the-MIBC acts as a frother to increase the affinity of bitumen to air bubbles. Although the description proceeds with reference to kerosene as a collector, it will be understood that other collectors having the characteristics of kerosene such as diesel fuel, No. 2 burner oil and the like may be satisfactory as a collector. In like manner, other frothers having the characteristics of MIBC may be used.
A ratio of K:MIBC of about 2:1 was found to provide optimum conditioning of the bitumen.
The process of the invention and its utility will now be discussed with reference to the following non-limitative examples.
Batch test extractions were employed to simulate the hot water extraction process. The extraction unit is a modified Denver(IM) flotation cell, operated at 10 to 13 rev/s to provide mixing for slurrying oil sand with hot water in a water jacketed stainless steel pot. The oil sand slurry was maintained at a desired temperature by circulating hot water from the water bath through the jacket of the pot.
A published procedure for the laboratory test on the hot water bitumen extraction from oil sand and its test conditions in accordance with the paper by Sanford, E.C.
and Seyer, F.A. entitled "Processibility of Athabasca Tar Sand Using a Batch Extraction Unit: The Role of NaOH", CIM
Bulletin, March 1979 was closely followed in this study.
The test procedure involves four distinct steps.
The pot is charged with 500 grams of oil sand lumps and 150 mL of hot water, the desired slurry temperature is 20~
` : !
established, and the charges are slurried at an impeller speed of 10 rev/s for 10 minutes with air aeration at 7 mL/s at the same time. This step simulates oil sand slurrying in the tumblers in the continuous process. An additional 1000 mL of hot flood water is then added at the end of 10 minutes. This step approximates the separation process in the primary vessels. The mixing is then continued at the same speed for another 10 minutes without aeration before the floated bitumen is s~i ^d. The slurry next is subjected to another 5 minutes of mixing at 13 rev/s while air is injected at approximatrely 3.9 mL/s to simulate secondary recovery. At the end of the run, product froth is collected in the same manner as secondary froth. Finally, the r ~ der in the pot is drained and analyzed for residual bitumen not recovered by the process.
For the bitumen recovery test run, tailings, primary and secondary froth samples are weighed and sent for bitumen/water/solids analyses. The analytical data are used for establishing material balance and bitumen recovery.
For the sludge settling data run, the tailings sample, after the removal of coarse sands, is allowed to settle in a lL graduated cylinder. The position of the interface between sludge and clear water is recorded with time. At the end of 10 days settling time, the sludge layer is separated from the clear water layer and analyzed for solids content or density.
A batch of oil sands sample was analyzed and the sample is shown in the following table.
- 10 ~
20~)4;~;2 - Table 1 Wt ~ Bitumen 9.5 Wt~ Water 3.5 'Wt~ Solids 87.0 Wt~ Fines in solids 22.6 As shown in Figure 3, the results of the tests using the conditioning agents of the present invention indicate that recovery increased steadily with increasing chemical level, varying from 65~ with no chemical addition to 93.8~ with 200 ppm chemicals addition. Beyond the 200 ppm level, recovery dropped slightly due to the chemical overdosing. The ratio of the collector chemical ~K~ to the frother chemical ~MI was maintained at the value of 2:1 for these tests. While the addition of the collector chemical ~K~ was meant to increase the hydrophobicity of the liberated bitumen, the addition of the frother chemical ~M) was used to improve the affinity of bitumen to air bubbles.
The test data as shown in Figure 3 indicate that addition of the two chenmicals to the the slurry significantly increased the bitumen recovery in the separation steps.
Tests using caustic addition also d~ -nstrated similar behavior, but the trend showing higher bitumen recovery with increases in caustic addition rate occurred only at much higher dosages, i.e. in the range between 400 and 1,100 ppm. The recovery ultimately reached over 90 when 1,100 ppm of caustic was added.
Tests were conducted to investigate the effectiveness of adding the conditioning agents of the invention and caustic at lower temperatures, i.e. 50 and 30OC. Results of these tests are shown in Figure 4 together with the 80OC test data. At the reduced temperatures, bitumen liberation is low, reflecting a low 20~4~i2 t--bitumen recovery obtained using both addition ofconditioning agents according to the present invention and addition of caustic.
It was found that tailings produced from the process using the conditioning agent of the invention settle rapidly and do not form a stable sludge. The tailings water clarify within in several days and can be reused. In comparison, tailings produced from the hot water extraction process using caustic settle slowly and usually take years to become a mature sludge (containing about 35~ solids).
To investigate the settling characteristics of the fines portion of the tailings obtained from the hot water extraction process using the conditioning agents of the invention and caustic, four tests were performed at 800C
using the above-described sample. Two of the tests were conducted by adding 1,100 ppm of caustic, and the other two by adding 200 ppm K:MIBCin the ratio of 2:1. The tailings consist of coarse sand, clay fines, water and a trace of bitumen ( 0.5~). The procedure which was generally followed comprised settling the coarse sand from the taillng slurry immediately following the bitumen separation steps as described above. The tailing water and clay fines were decanted into a one liter capacity graduated cylinder and allowed to settle for about a week to 10 days. In the case of the tailings produced according to the present invention, settling of the fines occurred as soon as the slurry established a quiescent state in the graduated cylinder, and two distinct layers were observed: (1) a loosely compacted layer of clay fines at the bottom of the graduated cylinder, and (2) a clear water phase on top of the clay sludge. The water phase appeared to be slightly 20~4~Ej2 murky initially, but began to clarify in about 15 minutes.
Later, the top water phase increased in volume as water from the solid phases continuously migrated upwardly to the clear water phase, thus increasing the density of the sludge phase. The location of the interface between the clear water layer and the sludge layer was recorded at various times throughout the test. At the end of the settling test? the supernatant liquid was separated from the sediment and the sediment was removed and oven dried to determine the amount of solids in the sludge.
The solid weight and the interface locations recorded during the tests provided the time variations of the tailing sludge density, which are shown in a semi-log plot in Figure 5. The tailing sludges from the two tests according to the present invention increased in density quite rapidly, reaching a pulp density of about 27% solids in about 5 days from the initial 6-7% solids content. In contrast, the caustic treated tailings remained practically unchanged at about 4.5% showing little or no fines settling duriing the same period. The above data indicate that the flotation tailings from the process of the present invention would settle much faster than the caustic treated tailings and hence would require less tailings pond area.
Further, a substantial amount of water can be made available for recycle when the conditioning agents of the invention are used in place of caustic in the process.
Tests were also conducted to investigate the strength of the settled fines. The procedure followed for this test was to allow settling of a whole tailings sample produced according to the present invention in a 2-liter graduated cylinder for about a week. Following this period, a portion of the top clear water was siphoned off ~, ~0~4~3æ
and a fresh batch of a simllarly prepared tailings sample was then added on top of the settled bed of fines from the first tailings sample. Another batch of sample was added in a similar fashion a week later. Changes of the interfaces between various layers due to either fines settling or compression from the top layers were noted with time. The bed of the settled sand plu5 clay phases from the first sample appeared to support the second and third batches of tailings samples. The preliminary qualitative data suggest that the tailings produced by the process of the present invention can be layered alternatively between coarse sand and fines clay, and would not create sludge problems such as these experlenced with the caustic dosed tailings. Such a layering phenomenon was not observed in a similar test with the tailings from the caustic hot water process in which the coarse sands from the second tailing sample sank through the clay phase to the bottom.
The present invention provides a number of important advantages. The quantity of conditioning agents required for a hot water process separation of bitumen from oil sands is substantially reduced resulting in the cost savings. The quality of bitumen produced is not adversely affected by the conditioning agents while the settling characteristics of tailings fines are substantially enhanced compared to tailings fines produced by the hot water process using caustic. The conditioning agents and air for further flotation can be introduced and intimately admixed with the slurry in a pipeline before introduction to a separation vessel.
The separation vessel preferably has a froth flotation-gravity separation zone into which the conditioned and aerated slurry is fed below the surface ~- Z0~4352 thereof for effective frothing of the bitumen and a quiescent zone.
It will be understood of course that modifications can be made in the embodiment of the process and apparatus of the invention illustrated and described herewin without departing from the scope and purview of the invention as defined by the appended claims.
Claims (11)
1. A process for the separation and recovery of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises the steps of slurrying 30 to 70% by weight oil sands in water, heating said slurry to a temperature in the range of about 30 to about 90°C, adding an effective amount of conditioning agents having the characteristics of kerosene and methyl-isobutyl carbinol and air to said slurry and intimately admixing said conditioning agents and air with the slurry, feeding said conditioned and aerated slurry into said separation vessel, and recovering bitumen as a froth.
2. A process for the separation of bitumen from oil sands containing bitumen and coarse and fine solids in a separation vessel which comprises slurrying 30 to 70% by weight oil sands in water, heating said slurry to a temperature in the range of about 30 to about 90°C , pumping said slurry through a pipeline to the separation vessel, adding to the slurry an effective amount of conditioning agents having the characteristics of kerosene and methyl-isobutyl carbinol and air in the pipeline prior to feeding said slurry into said separation vessel for intimate admixture of the conditioning agents and air with the slurry, and feeding said conditioned and aerated slurry underwater into the separation vessel in a froth flotation-gravity separation zone wherein bitumen floats to the surface as a froth and coarse solids and a portion of fines fall by gravity to a bottom discharge portion of the vessel.
3. A process as claimed in claim 1 or 2 wherein said slurry is heated to about 80°C.
4. A process as claimed in claim 1 or 2 wherein said slurry is heated to about 80°C, and wherein said conditioning agents have the characteristics of kerosene and methyl-isobutyl carbinol in an effective amount in the range of about 200 to 400 ppm.
5. A process as claimed in claim 1 or 2 wherein said slurry is heated to about 80°C, wherein said conditioning agents have the characteristics of kerosene and methyl-isobutyl carbinol in an effective amount in the range of about 200 to 400 ppm, and wherein said kerosene and methyl-isobutyl-carbinol are present in the ratio of 2:1.
6. A process as claimed in claim 4 in which said separation vessel has a froth flotation-gravity separation zone and a quiescent zone adjacent thereto.
7. A separation vessel for separating and recovering bitumen from an oil sands slurry comprising a froth flotation-quiescent zone having a cone discharge bottom, a feed inlet for introducing the oil sands slurry thereinto below the surface of a froth layer therein for separation of bitumen as a froth from coarse sand and a portion of fines, a quiescent zone contiguous to said froth-flotation quiescent zone for receiving remaining bitumen and fines for continued separation of bitumen from the fines, means for removing the bitumen as a froth from the vessel, and means for collecting coarse sand and fines from the froth flotation-gravity separation zones for discharge from the bottom of the vessel.
8. A separation vessel as claimed in claim 7 in which said means for collecting the coarse sand and fines comprises at least one cone bottom below the froth flotation-gravity separation zone and the quiescent zone.
9. A separation vessel as claimed in claim 8 in which said vessel is horizontally elongated having a feed inlet into the froth flotation-gravity separation zone at one end adjacent the cone bottom and the quiescent zone contiguous thereto has a rake therebeneath for raking settled solids into the cone bottom.
10. A separation vessel as claimed in claim 8 in which said vessel is horizontally elongated having a feed inlet into the froth flotation-gravity separation zone at one end adjacent the cone bottom and the quiescent zone contiguous thereto has a series of cone bottoms for collecting coarse sand and fines for discharge from the bottom of the vessel.
11. A separation vessel as claimed in claim 7, 8 or 9 in which said feed inlet comprises an outer cone concentric with an inner cone defining a conical annulus of uniformn width therebetween open-ended into the froth flotation-gravity separation zone below the surface of the front layer, said outer cone having a plurality of openings formed therein for the uniform dispersion of small air bubbles and slurry into said froth flotation-gravity separation zone.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2004352 CA2004352C (en) | 1989-12-01 | 1989-12-01 | Hot water extraction process and apparatus |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2004352 CA2004352C (en) | 1989-12-01 | 1989-12-01 | Hot water extraction process and apparatus |
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| CA2004352C true CA2004352C (en) | 1995-02-21 |
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| WO2016064495A1 (en) * | 2014-10-22 | 2016-04-28 | Exxonmobil Upstream Research Company | Horizontal-flow oil sands separator for an aqueous extraction process |
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| US8127842B2 (en) | 2008-08-12 | 2012-03-06 | Linde Aktiengesellschaft | Bitumen production method |
| US20120228195A1 (en) | 2011-03-09 | 2012-09-13 | Zhixiong Cha | Method for improving oil sands hot water extraction process |
| US20190225889A1 (en) | 2016-07-18 | 2019-07-25 | Dow Global Technologies Llc | Method to extract bitumen from oil sands using aromatic amines |
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| WO2016064495A1 (en) * | 2014-10-22 | 2016-04-28 | Exxonmobil Upstream Research Company | Horizontal-flow oil sands separator for an aqueous extraction process |
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