U.S. patent application number 12/181131 was filed with the patent office on 2008-11-13 for separation and recovery of bitumen oil from tar sands.
This patent application is currently assigned to RJ OIL SANDS INC.. Invention is credited to Wade Ralph Bozak, Roderick Michael Facey.
Application Number | 20080277318 12/181131 |
Document ID | / |
Family ID | 35637041 |
Filed Date | 2008-11-13 |
United States Patent
Application |
20080277318 |
Kind Code |
A1 |
Bozak; Wade Ralph ; et
al. |
November 13, 2008 |
SEPARATION AND RECOVERY OF BITUMEN OIL FROM TAR SANDS
Abstract
A process for the separation of bitumen oil from tar sands and
the like. Slurry is supplied to a mixing chamber of a jet pump at
an input end of the process. The slurry is agitated within the jet
pump to effect a partial to full phase separation of the oil
fraction from the solids fraction of the slurry. The partially to
fully separated slurry is discharged into a pipeline and later into
a hydrocyclone to effect a second phase separation of the slurry.
One or more hydrocyclone separators may be used to separate the
bitumen oil and liquid from the solids fraction.
Inventors: |
Bozak; Wade Ralph;
(Edmonton, CA) ; Facey; Roderick Michael;
(Edmonton, CA) |
Correspondence
Address: |
CHRISTENSEN, O'CONNOR, JOHNSON, KINDNESS, PLLC
1420 FIFTH AVENUE, SUITE 2800
SEATTLE
WA
98101-2347
US
|
Assignee: |
RJ OIL SANDS INC.
New Westminster
CA
|
Family ID: |
35637041 |
Appl. No.: |
12/181131 |
Filed: |
July 28, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10895364 |
Jul 21, 2004 |
7416671 |
|
|
12181131 |
|
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Current U.S.
Class: |
208/390 |
Current CPC
Class: |
C10G 1/047 20130101 |
Class at
Publication: |
208/390 |
International
Class: |
C10G 1/04 20060101
C10G001/04 |
Claims
1. A process for phase separation of tailings comprising a solids
fraction and an oil and water fraction, the process comprising the
steps of: supplying the tailings to a mixing chamber of a jet pump,
the jet pump being supplied with wash fluid from a power source;
agitating the tailings within the mixing chamber of the jet pump to
effect a partial to full phase separation of the oil and water
fraction from the solids fraction of the tailings; and discharging
of the partially to fully separated oil and water fraction and
solids fraction of the tailings from the jet pump.
2. The process of claim 1 in which the jet pump operates at a
Reynolds number above 250,000.
3. The process of claim 1 in which the slurry is supplied from a
hopper, wherein the hopper is free of phase separation devices.
4. The process of claim 1 in which the partially to fully separated
oil and water fraction and solids fraction of the tailings is
discharged from the jet pump into a phase separation device.
5. The process of claim 1 in which discharging further comprises
discharging the partially to fully separated oil and water fraction
and solids fraction of the tailings from the jet pump into a
pipeline for continued separation through mixing and contact with
the wash fluid within the pipeline.
6. The method of claim 5, further comprising discharging the
partially to fully separated mixture of the oil and water fraction
and the solids fraction of the tailings from the pipeline into a
phase separation device to effect a second phase separation of the
tailings and produce a first output stream comprising the solids
fraction and a second output stream comprising the oil and water
fraction.
7. The process of claim 6 further comprising repeating the process
steps of claim 6 to yield a solids fraction and chemically
conditioning the solids fraction with calcium oxide.
8. The process of claim 6 further comprising treating all or
portions of the first output stream with a thermal screw to produce
a solids fraction free of any residual water and hydrocarbons.
9. The process of claim 6 in which the phase separation device
comprises a hydrocyclone.
10. The process of claim 1 in which the tailings comprises tailings
from a mining or drilling operation.
11. A method for treating a mixture comprising tailings, the
mixture having a solids fraction, a hydrocarbon fraction, and a
water fraction, the method comprising the steps of: supplying the
mixture to a mixing chamber of a jet pump; supplying a primary flow
to an input of the jet pump; and operating the jet pump using the
primary flow to agitate the mixture and propel an agitated mixture
from the jet pump to effect at least a partial phase separation of
the hydrocarbon fraction from the solids fraction and the water
fraction.
12. The process of claim 11 in which the agitated mixture is
discharged from the jet pump into a phase separation device.
13. The method of claim 11 in which the agitated mixture is
discharged from the jet pump into a pipeline for continued
separation through mixing and contact with the wash fluid within
the pipeline.
14. The method of claim 13 further comprising discharging the
agitated mixture from the pipeline into a phase separation device
to effect a second phase separation of the agitated mixture and
produce a first output stream comprising the solids fraction and a
second output stream comprising the hydrocarbon fraction and the
water fraction.
15. The method of claim 11 in which the mixture is supplied from a
hopper, and in which the hopper is free of phase separation
devices.
16. The method of claim 11 in which the jet pump operates at a
Reynolds number above 250,000.
17. The method of claim 14 in which the phase separation device
comprises a hydrocyclone.
18. A process for phase separation of a mixture comprising tailings
and having a solids fraction and a hydrocarbon fraction, the
process comprising the steps of: supplying the mixture to a mixing
chamber of a jet pump; supplying a primary flow to an input of the
jet pump; and operating the jet pump using the primary flow to
agitate the mixture and discharge the agitated mixture from the jet
pump to effect at least a partial phase separation of the
hydrocarbon fraction from the solids fraction.
19. The process of claim 18 in which the agitated mixture is
discharged from the jet pump into a phase separation device.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of prior U.S.
non-provisional application Ser. No. 10/895,364 filed Jul. 21,
2004.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a method for separating bitumen
oil from tailings.
[0003] The current industry practice for extracting bitumen from
tar sands and the like is the hot water process, utilizing
aggressive thermal and mechanical action to liberate and separate
the bitumen. The hot water process is typically a three-step
process. Step one involves conditioning the oil sands by vigorously
mixing it with hot water at about 95 degrees Celsius and steam in a
conditioning vessel to completely disintegrate the oil sands. Step
two is the gravity separation of the sand and rock from the slurry,
allowing the bitumen to float to the top where it is concentrated
and removed as a bitumen froth. Step three is treatment of the
remainder slurry, referred to as the middlings, using froth
floatation techniques to recover bitumen that did not float during
step two. To assist in the recovery of bitumen during step one,
sodium hydroxide, referred to as caustic, is added to the slurry in
order to maintain the pH balance of the slurry slightly basic, in
the range of 8.0 to 8.5. This has the effect of dispersing the
clay, to reduce the viscosity of the slurry, thereby reducing the
particle size of the clay minerals.
[0004] A problem related to the industry practice is that the
addition of caustic, coupled with the vigorous and complete
physical dispersal of the fines, produces a middlings stream that
may contain large amounts of well dispersed fines held in
suspension. The recovery of bitumen from these middlings stream
increases with the increase in the fines concentration over time.
In addition, the middling stream that remains following step three,
referred to as the scavenging step, poses a huge disposal problem.
Current practice for the disposal of the resultant sludge involves
the pumping of the sludge into large tailings ponds. This practice
poses serious environmental risks.
[0005] The industry practice for the extraction of bitumen from oil
sands has been to maximize the recovery of bitumen while minimizing
the production of sludge, which require treatment and disposal. The
industry practice typically provides for a bitumen recovery of
between about 80% and 95% of the total amount of bitumen contained
in the oil sands. Lower bitumen recoveries are experienced with oil
sands of high fine material and low bitumen contents. To increase
bitumen recovery, methods have arisen to reheat and recycle water
recovered during the solids de-watering phase to re-expose the
suspension of dispersed fine material to the conditioning bath,
whereby the dispersed fine material may undergo further froth
floatation treatment for bitumen recovery.
SUMMARY OF INVENTION
[0006] A process for the separation of bitumen oil from tailings is
disclosed. In an embodiment, slurry comprising tailings is supplied
to a mixing chamber of a jet pump at an input point of the
separation process. The slurry is agitated within the jet pump to
effect a partial to full phase separation of the oil and water
fraction from the solids fraction of the slurry. One or more phase
separation devices, for example hydrocyclone separators, may be
used to separate and concentrate any remaining residual bitumen oil
and liquid from the solids fraction.
[0007] In some embodiments, the process distinguishes itself from
others in that it does not require the use of elutriation vessels,
clarifiers, separators, baths or similar devices to condition
and/or to separate the oil and liquids from the solids fraction.
Bitumen separation may be achieved during mixing within the jet
pump and within the pipeline. The extraction of bitumen oil from
the tar sands and the release of the solid particles from the oil
sand matrix continues in the slurry exiting the jet pump as the jet
pump transports the slurry to the material separation and
classification process.
[0008] Pre-conditioning of the raw material is not a requirement of
this process, greatly reducing the infrastructure of the plant.
Rather the solids fraction of the slurry is physically and/or
chemically conditioned by the wash fluid that can consist of a cold
or hot water, or a solvent or a water chemically treated or a
mixture of all. In some embodiments, the use of elutriation
vessels, clarifiers, separators, baths or the like may be replaced
with hydrocyclone separators. The hydrocyclone separators are
designed to separate and classify the slurry stream using
centrifugal forces into two stream fractions consisting of water
and oil and solids. The processes disclosed herein can be applied
to separate bitumen attached to any type of solid. Further,
multiple wash step loops are possible to maximise bitumen
separation and recover, or to achieve any level of treatment
recovery desired.
[0009] An apparatus according to an aspect of the invention
comprises hopper, motive pump, jet pump, pipeline, and hydrocyclone
separator. The hopper is designed to receive the raw material and
can be shaped as a cone bottom vessel or alternatively equipped
with a mechanical auger designed to convey material to the inlet of
the jet pump. The motive pump is designed to supply the high
pressure fluid necessary to operate the jet pump which by use of a
nozzle within the jet pump the fluid is converted into a high
velocity jet to produce a vacuum within the mixing chamber of the
jet pump to suction the tar sands into the inlet of the jet pump.
Further aspects of the invention are described in the detailed
description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] An exemplary embodiment is now described in detail with
reference to the drawings, in which:
[0011] FIGS. 1A-1F are flow charts of a process of separation and
recovery of bitumen from tar sands in which the proposed invention
may be used, in which FIG. 1A shows a first wash treatment process
of the input slurry with water, FIG. 1B shows wash steps with
solvent on the heavier output from the steps of FIG. 1A, FIG. 1C
shows wash steps with water on the heavier output from FIG. 1B,
FIG. 1D shows a first oil\water separation treatment process on the
lighter output from the process of FIG. 1A, FIG. 1E shows process
steps for the treatment of de-watered solids using a thermal screw,
FIG. 1F shows treatment of recovered wash water;
[0012] FIG. 1G is a flow chart that shows the interrelationship of
FIGS. 1A-1F;
[0013] FIG. 2 is a schematic of the feed hopper, jet pump, pipeline
and hydrocyclone according to the invention; and.
[0014] FIG. 3 is a detailed schematic of a jet pump for use in a
method according to the invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0015] With reference to FIGS. 1A-1F, an overview of a process for
the separation and recovery of bitumen oil from tar sands and the
like is described. Tar sands, also referred to as oil sands, are a
matrix of bitumen, water, and mineral material. The bitumen
consists of viscous hydrocarbons, which acts as a binder for the
other components of the oil sand matrix. A typical deposit of oil
sand will contain about 10% to 12% bitumen and about 3% to 6%
water. The mineral material consists of rock, sand, silt and clay.
Clay and silt are considered to be fines. Mineral material can
contain about 14% to 30% fines. Although it is understood that the
described process and apparatus may be applied to removing oil from
any type of particulate material, in accordance with a preferred
embodiment of the invention, the process and apparatus are applied
to separating and recovering bitumen oil from tar sands, such as
that derived from mining or drilling operations.
[0016] As shown in FIG. 1A, tailings 1 from, for example a mining
or drilling operation, may be fed into a receiving hopper 2 via
preferably a belt conveyor 3 or alternatively via a front end
loader 4 at an input end of the tar sands separation process. At
the input end, the unprocessed tar sands have undergone little or
no processing, and no phase separation. The belt conveyor 3
features a troughed belt on 20 degree or greater idlers and are
readily available in the industry. The receiving hopper 2 may be
supplied with a mechanical grinder 5 and has its discharge coupled
to a jet transfer pump 6. The mechanical grinder 5 is also readily
available in the industry. The jet pumps 6 is also readily
available in the industry, such as those manufactured by Genflo
Pumps, but some care must be taken in choosing the jet pump, and it
is preferred to use the jet pump shown in FIG. 3. The jet pump 6
should operate at a high Reynolds number, above 250,000, and
preferably in the order of 650,000 to 750,000. Such a Reynolds
number may be obtained by a combination of high pressure, for
example 80 psi or more, and a sufficiently long mixing chamber, as
for example shown in FIG. 3. All jet pumps described in this patent
document preferably have this configuration.
[0017] As the tar sands enter the receiving hopper 2 they may be
mechanically ground, preferably using a mechanical grinder 5 to
produce particles 50 mm in size or smaller. The jet transfer pump 6
at the respective base of cone 7 of the receiving hopper 2 mixes
the ground tar sands 1 with a hot water stream from line 8 to
produce a hot slurry mixture in line 9 which is passed into a first
hydrocyclone separator 10. Centrifugal forces within the first
hydrocyclone separator 10 separate a large portion of the solids
from the bitumen oil and water mixture. The solids are removed from
the bottom of hydrocyclone separator 10 and gravity discharged into
cone bottom hopper 11. The remaining slurry mixture, comprising
primarily of the bitumen oil and water, in line 12, is gravity
discharged into a centrate collection tank 13. Any residual solids
in this stream settle to the bottom of the centrate collection tank
13. The oil and water are removed from the top at point 14 of the
centrate collection tank. A further jet transfer pump 15 located at
base 16 of the centrate collection tank 13 removes and mixes the
solids with the hot water stream in line 17 and passes it through
line 18 to a second hydrocyclone separator 19. Centrifugal forces
within the second hydrocyclone separator 19 separate the remaining
portion of the solids from the oil and water fractions. The solids
are removed from the bottom of hydrocyclone separator 19 and
gravity discharged into the cone bottom hopper. A jet transfer pump
20 located at base 21 of the cone bottom hopper 11 removes and
mixes the solids with the hot water stream in line 22 and passes it
through line 23 to the inlet of centrifuge 24. Optionally, the
water wash step can be repeated multiple times with each step
identical to the preceding step.
[0018] As shown in FIG. 1B, solids removed from the bottom of the
cone bottom hopper 11 are de-watered using centrifuge 24,
preferably a basket or solid bowel centrifuge. Alternative
mechanical dewatering technology such as inclined dewatering screws
or belt filter presses can also be used. De-watered solids 25 are
discharged into a cone bottom receiving hopper 26. A jet transfer
pump 27 at the base of the cone 28 of the receiving hopper 26 mixes
the solids with the heated solvent stream from line 29 to produce
the heated slurry mixture in line 30 which is passed into the first
hydrocyclone separator 31. Centrifugal forces within the first
hydrocyclone separator 31 separate a large portion of the solids
from the oil and solvent mixture. The solids are removed from the
bottom of hydrocyclone separator 31 and gravity discharged into the
cone bottom hopper 32. The remaining slurry mixture, comprised
primarily of the oil and solvent, in line 33, is gravity discharged
into the centrate collection tank 34. Any residual solids in this
stream settle to the bottom of the centrate collection tank 34. The
oil and solvent are separated from the top of centrate collection
tank at point 35. The jet transfer pump 36 located at the
respective base 37 of the centrate collection tank 35 mixes the
solids with the heated solvent stream in line 38 and passes it
through line 39 to the second hydrocyclone separator 40.
Centrifugal forces within the second hydrocyclone separator 40
separates the remaining portion of the solids from the oil and
solvent mixture. The solids are removed from the bottom of
hydrocyclone separator 40 and gravity discharged into the cone
bottom hopper 32. Optionally, the solvent wash step can be repeated
multiple times with each step identical to the preceding step.
[0019] Referring to FIG. 1C, solids that are deposited in cone
bottom hopper 32 are removed via jet pump 41 at base 42 and
de-watered by centrifuge 43, preferably using a basket or solid
bowel centrifuge. Other alternative mechanical dewatering
technology can be used such as inclined dewatering screws and or
belt filter presses. De-watered solids 44 are gravity discharged
into a cone bottom receiving hopper 45. Jet transfer pump 46 at the
base of the cone 47 of the receiving hopper 45 mixes the de-watered
solids with the hot water stream from line 48 to produce the hot
slurry mixture in line 49 which is passed into a hydrocyclone
separator 50. Centrifugal forces within the first hydrocyclone
separator 50 separate a large portion of the solids from the oil
and water mixture. The solids are removed from the bottom of
hydrocyclone separator 50 and gravity discharged into cone bottom
hopper 51. The remaining slurry mixture, comprised of the oil and
water, in line 52, is gravity discharged into centrate collection
tank 53. The solids settle to the bottom of the centrate collection
tank 53. The oil and water are removed from the top at point 54 of
the centrate collection tank. Jet transfer pump 55 located at base
56 of centrate collection tank 54 removes and mixes the solids with
the hot water stream in line 57 and passes it through line 58 to a
second hydrocyclone separator 59. Centrifugal forces within the
second hydrocyclone separator 59 separate the remaining portion of
the solids from the oil and water mixture. The solids are removed
from the bottom of hydrocyclone separator 59 and gravity discharged
into the cone bottom hopper 51. Optionally, the hot water wash step
can be repeated multiple times with each step identical to the
preceding step. As a further option, the solids collected from cone
bottom hopper 51, mostly clays and silts, can be further treated by
further thickening then fed into a thermal screw. There, the solids
may be mixed with calcium oxide. The use of calcium oxide is
contemplated in an embodiment of the invention to chemically
condition the solids. Calcium oxide addition is to coagulate the
solids to release sorbed water, which if added in sufficient
concentration will locally increase the temperature of the solids,
coupled with the heat input form the other direct and indirect
heating systems can cause the water and any residual hydrocarbons
to vaporize. The thermal screw may be equipped with a vapour
recovery system since the reaction would be exothermic. A dry
solids stream is produced after the oxidation of any remaining
hydrocarbons in the clay and silt slurry.
[0020] Solids that are deposited in the cone bottom hopper 51 are
removed via jet pump 60 at the base 61 and mixed with hot water
stream in line 62 and passes it through line 63 the inlet of
centrifuge 64 preferably using a basket or solid bowel centrifuge.
Other alternative mechanical dewatering technology can be used such
as inclined dewatering screws and/or belt filter presses.
De-watered solids 65 can be optionally discharged into receiving
pile 66 or alternatively discharged into cone bottom receiving
hopper 67 for thermal treatment. Solids requiring additional
thermal treatment for treatment and recovery of any residual
hydrocarbons or alternatively for further drying are to be blended
and mixed with calcium oxide in a controlled manner directly within
the thermal screw at the inlet point of the thermal screw. Mixing
calcium oxide with moist solids chemically reacts with the moisture
associated with the solids to locally increase the temperature of
solids through direct heating caused by the exothermic reactions,
causing both moisture and residual hydrocarbons to vaporize. The
mix ratio of calcium oxide is a function of the desired temperature
increase, which to achieve can require the addition of water to the
solids in hopper 67. Residual de-watered solids, consisting of the
clays and silts recovered from the wastewater treatment process can
be discharged via line 68 into the cone bottom receiving hopper 67
for thermal treatment.
[0021] Referring in particular to FIG. 1E, subsequently, and
optionally, a thermal screw 69 may be used to treat a portion of
the entire solids fraction for removal of any residual hydrocarbons
or alternatively for further drying. The thermal screw 69 is
configured to contemplate the direct and indirect heating of the
solids for treatment by exposing the solids directly to direct heat
produced through the addition of calcium oxide and through the
addition of either hot exhaust gases from a combustion engine or
alternatively a hot inert gas. Calcium oxide is to be metered
directly into the thermal screw at the inlet point for blending and
mixing with the solids. Indirect heating is provided by the heater
system 73 which can consist of the heating of the outside trough
surface of the thermal screw using electric heaters, or an outside
jacket designed to receive and circulate hot oil or alternatively
steam for contact with the surface. A rotary valve 70 at the base
of cone 71 of the receiving hopper 67 meters the de-watered solids
into the thermal screw 69. A rotary valve (not shown) at the base
of cone 174 meters calcium oxide into the solids fraction as it
enters the thermal screw 67. Both rotary valves are equipped with a
variable frequency drive to provide operational control of the feed
input. The thermal screw 69 preferably consists of a screw conveyor
complete with a gas manifold collection system 72, heating system
73, cooler 74, gas-liquid separator 75, blower 76, inert gas
storage system 77, and inert gas recycle system at point 78. The
de-watered solids are introduced into the thermal screw at point
69. Hot inert gas from the inert gas recycle system 78 or
alternatively the hot exhaust gases from a combustion engine (not
shown) is introduced into the thermal screw using a rotary swivel
at 79 via line 80. Prior to introduction into the thermal screw 69
the inert gas is indirectly heated to the operating temperature of
the thermal screw through the wrapping of the inert gas line 81
between the heater system 73 and body of the thermal screw 82. In
the case where hot exhaust gases are used, the gases can be
injected directly into the thermal screw without indirect
pre-heating of the gases. Hot gases 83 from within the thermal
screw 69 consisting principally of vaporized hydrocarbons and water
vapor are removed under a vacuum in the case where an inert gas
storage supply is used or alternatively under positive pressure in
the case where hot exhaust gases from a combustion engine are used
for direct heating and the maintaining of a non-oxidizing
environment within the thermal screw from the thermal screw via
line 84 at multiple gas discharge ports on top of the screw housing
shown at the respective locations 85, 86 and 87.
[0022] The hot gases removed from the thermal screw via line 84 are
separated into two gas streams at point 88. Hot gases in line 89
are passed into the water knockout drum 90 for water removal after
which the gases pass through line 91 to the fuel inlet system of
the gas fired co-generation unit 92.
[0023] Hot gases in line 93 are passed into the cooler at point 94,
where the hot gas mixture is cooled using an air cooler 74.
Alternatively, a chiller may be used instead. Exiting via line 95
from the cooler 74 is a cooled multi-phase mixture consisting of
the inert gas and liquid droplets of oil and water. The mixture
enters the gas-liquid separator 75 at point 96 where the condensate
is separated from the inert gas. The inert gas exits the gas-liquid
separator 75 via line 98.
[0024] Blower 76 preferably a rotary lobe blower withdraws the hot
gases from the thermal screw under a vacuum or positive pressure
depending on the source and nature of the hot gases used for direct
heating and maintenance of the non-oxidizing environment. The
blower is equipped with a variable speed drive to control the
vacuum pressure under which the thermal screw 69 is operated.
[0025] The inert gas is discharged from the blower 76 via line 99,
where at point 101, the line is split into two gas streams shown
via lines 102 and 103. Control valves 104 and 105 and gas flow
meter 106 regulate the inert gas flow that is recycled to the
thermal screw 69. Inert gas via line 107 and recycled gas 108 are
indirectly heated using the hot outside surface of the thermal
screw housing before entering the swivel connection at 78 of the
holoflyte screw auger of the thermal screw. Excess exhaust gas, via
line 102, enters a vapor recovery unit 109 where the gas is further
chilled to remove any residual hydrocarbons and vaporized metals.
The inert gas is discharged from the vapor recovery system via line
110 to the atmosphere at point 111. Optionally the entire inert gas
stream via line 99 can be recycled via line 103 or alternatively
discharged via line 102 to be processed by the vapor recovery unit
109 as would be the case for hot exhaust gases utilized from a
combustion engine for direct heating.
[0026] Referring in particular to FIG. 1D, oily materials separated
by hydrocyclone separators 10, 19, 31, 40, 50 and 59 and discharged
into centrate collection tanks 13, 34 and 53 via lines 12, 33, and
52 are treated separately for the recovery of bitumen oil for the
different oil-water mixtures via lines 112 and 114 and oil-solvent
mixture streams via line 113. All, or a portion of all, the solids
fraction de-watered using the centrifuges 115 and 116 are gravity
discharged into the feed hoppers 45 and 67 of the thermal screw 69.
The oil-water fraction of the oily material deposited in centrate
collection tank 13 overflows via line 112 into a floatation unit
175. Air is introduced via a line 176 into the floatation unit 175
through fine bubble diffusers at 117 to produce fine bubbles to
float and concentrate the bitumen oil to produce a froth which
discharges via line 118 into the oil-water separator 119.
[0027] The concentrated oil-water mixture is removed at point 120
of the floatation unit 175 and passed via line 118 to the oil/water
separator 119. The oil water separator 119 separates the oil from
the water, with the oil removed via line 121 and passed into the
oil storage tank 122. The water is removed via line 123 which then
interconnects with line 124 to form line 125 which is passed into
the rapid mix tank 126.
[0028] The water mixture enters the rapid mix tank 126 where it is
treated with the primary coagulant 127 introduced via a line into
the mix tank 128. Synthetic polymers are the preferred coagulant,
but metal-based coagulants can also be used. The treated water
mixture exits the rapid mix tank 126 via line 129 and enters into
the flocculation unit 130. The treated water mixture flows through
a series of baffled slow mix chambers equipped with slow rotating
mechanical mixers. Residual particles in the water mixture are
coagulated and agglomerated within the flocculation unit.
[0029] The coagulated water exists the flocculation unit 130 via
line 131 and enters into the sedimentation tank 132. The coagulated
solids are gravity settled in the sedimentation tank 132. The jet
pump 133 at the base 134 of the sedimentation tank 132 removes and
transfers the coagulated solids via line 135 to the mechanical
de-watering unit 116, preferably a basket or solid bowel
centrifuge. The de-watered solids exits the centrifuge via line 136
and are transferred to the cone bottom receiving hopper 67 of the
thermal screw 69.
[0030] Referring in particular to FIG. 1F, the water from the
sedimentation tank 132 overflows via a weir at point 137 and is
discharged via line 138 to the surge tank 139. From surge tank 139
the water is pumped via line 140 into the filtration unit 141 for
the removal of any residual solids carryover from the sedimentation
tank 132. Residual solids are captured within filtration unit 141.
The clarified water exits the filtration unit 141 via line 142 and
enters the storage tank 143. From the storage tank water enters the
vacuum filtration unit 144.
[0031] Optionally, the filter unit 141 and vacuum filtration unit
144 may be by-passed via line 145 with the clarified water directly
recycled via line 146 to the water storage tank 147.
[0032] Clarified water via line 148 enters the vacuum filtration
unit 144 where it is heated under a vacuum to produce distilled
water. Distilled water exits via line 149 from the vacuum
filtration unit 144 where it is pumped to the water storage tank
147. The brine concentrate containing the impurities is discharged
from the vacuum filtration unit 144 via line 150 into the
concentrate tank 151 for disposal. Optionally, the concentrate can
be recycled back to the vacuum filtration unit using a control loop
that relies on the resultant brine concentration for additional
distillation to recover as much as distilled water as possible.
[0033] With reference to FIG. 2, the operation of a preferred feed
hopper, jet pump and hydrocyclone is described in further detail.
The tar sands material is first deposited into feed hopper 152 that
has an elongated trough at its base within which lies an auger 153.
The tar sands material is then augured with auger 153 to the inlet
of the jet pump 154. A pressurized wash fluid 155 is fed to the
inlet nozzle 156 of the jet pump 154 using a conventional
centrifugal pump (not shown). The jet pump inlet nozzle 156 directs
a flow into the mixer 157 educting the tar sands into the jet pump
154 where extreme turbulence and mixing occurs at point 158. The
slurry flow slows in velocity in the diffuser 159. The slurry then
flows into an engineered pipeline 160 of a sufficient length
required to optimize separation for the wash fluid used from where
it enters the entrance of the hydrocyclone 161. A centrifugal force
is created in the upper chamber 162 of the hydrocyclone. The solids
are forced to the outside of the hydrocyclone at point 163 and the
wash fluid and bitumen are forced to the center of the hydrocyclone
at point 164. The solids exit the hydrocyclone at the vortex 165 as
an underflow. The wash fluid and bitumen exit the hydrocyclone as
an overflow at point 166 at the top of the hydrocyclone. The wash
fluid and bitumen are transported in a flexible pipeline 167 to the
next phase which can be a repeat of the first step.
[0034] With reference to FIG. 3, the operation of the jet pump 154
(FIG. 2) is described in further detail. Unlike other pumps, a jet
pump has no moving parts. A typical jet pump consists of the
following: a jet supply line 168, a nozzle 169, a suction chamber
171, a mixing chamber 172 and a diffusor 173 leading to a discharge
line. In a jet pump, pumping action is created as a fluid (liquid,
steam or gas) passes at a high pressure and velocity through the
nozzle 169 and into a chamber 171 that has both an inlet and outlet
opening. Pressurised wash fluid is fed into the jet pump 154 (FIG.
2) at jet supply line 168. The wash fluid passes through inlet
nozzle 169, where it meets tar sand material gravity fed from
hopper inlet 170 at the suction chamber 171. The resulting slurry
is mixed and agitated within the mixing chamber 172 where it
undergoes an initial phase separation of oil fraction from solid
fraction. The agitated slurry slows in velocity in the diffuser
173. Upon entry into the jet pump 154 (FIG. 2), the tar sands
material from hopper 152 is entrained and mixed with the wash fluid
from the nozzle 169, which undergoes a substantial pressure drop
across the jet pump 154 (FIG. 2) and causes extreme mixing of the
slurry. The extreme mixing and pressure drop causes cavitation
bubbles to develop on the inside of chamber 171, which implode on
solid particles to enhance the separation of the bitumen oil from
the solid particles.
[0035] The jet pump of the present invention functions as an
ejector or an injector or an eductor, distinct from a venturi pump
and an airmover. A venturi has little in common conceptually with a
jet pump. A venturi is a pipe that starts wide and smoothly
contracts in a short distance to a throat and then gradually
expands again. It is used to provide a low pressure. If the low
pressure is used to induce a secondary flow it becomes a pump,
resulting in a loss of pressure in the throat. If the secondary
flow is substantial the loss will be too great to have a venturi
operate like a pump. To operate like a pump it would have to be
redesigned as a jet pump. Venturi pumps have limited capacity in
applications like chemical dosing where a small amount of chemical
is added to a large volume of fluid. A jet pump is a pump that is
used to increase the pressure or the speed of a fluid. Energy is
put into the fluid and then taken out by a different form. In a jet
pump energy is added by way of a high speed jet fluid called the
primary flow. In the design shown in FIG. 3, the primary flow is
produced by jet nozzle 169. Energy is taken out mostly as increased
pressure of a stream of fluid passing through. In a jet pump this
stream is called the secondary flow and it is said to be entrained
by the primary flow. A jet pump is designed to be energy efficient.
A venturi pump does not have the capacity to induce large volumes
of flow, where as a jet pump can and operate energy efficient.
Unlike a venturi pump, a jet pump consists of a nozzle, mixing
chamber and diffuser. In a jet pump these components are
specifically engineered to have the pump operate energy efficient.
A venturi pump does not have a defined nozzle, but instead a
constriction in the pipe. It also does not have a defined mixing
chamber.
[0036] The wash fluid can be combination of fluids used singularly
or in combination in multiple loops consisting of a chemically
treated or chemical free hot or cold water or alternatively a hot
or cold solvent. The wash fluid can chemically and/or physically
react with the bitumen oil to partition the oil to the liquid phase
to permit separation and recovery by hydrocyclone separation. The
continuous supply of wash fluid by the motive pump provides for the
transport of the tar sands carried in a wash fluid stream to
continue the extraction of bitumen from the oil sands in the
pipeline. Hydrocyclone separator 161 is used to classify and remove
the bitumen oil and water fraction from the solids fraction, with
the solid fraction deposited into a second hopper. If necessary,
the solids fraction can be repeatedly treated for additional
bitumen recovery by repeating the process.
Process Conditions
[0037] As the tar sands enter the receiving feed hopper, they are
mechanically ground, preferably using a horizontal shear mixer, to
reduce the solid particles to 25 mm in size or smaller. The motive
pump (not shown), preferably of a centrifugal pump, is configured
to draw chemical free hot water of a temperature at about 95
degrees Celsius from a hot water tank to produce a high pressure
water stream at the inlet of the jet pump. At the jet pump inlet
the high pressure water stream, at approximately 120 psi, is
converted within the jet pump nozzle into a high velocity water
jet, referred to as the primary flow. The substantial pressure drop
within the jet pump draws the slurry mixture from the hopper,
referred to as the secondary flow, into the jet pump where it is
mixed with the primary flow to achieve a resultant percent solids
concentration of 25% or less by volume.
[0038] The optional treatment of the clays and fines, collected
after the solids are collected from the first wash process, would
be thickened to approximately 60% solids before being fed into the
thermal screw.
[0039] This invention therefore contemplates the use of jet pumps
to effect separation of oil from solid particles. In some
embodiments, this method distinguishes itself from other processes
in that it does not require the use of elutriation vessels,
clarifiers, separators, baths or the like to condition and or
separate the oil and liquids from the solids fraction. Bitumen
separation may be achieved during mixing within the jet pump and
pipeline during transport. No other vessels or technologies are
required to effect separation of bitumen oil from solids. Therefore
the process is substantially simplified in comparison to existing
hot water or solvent bitumen extraction processes. The use of
centrifugal forces by way of hydrocyclones and centrifuges are
employed throughout the process for separation and classification
of the different stream fractions consisting of water, oil, and
solids. In accordance with aspects of this invention, physical,
chemical and thermal processes are employed to separate, treat and
recover bitumen oil from solid particles, irrespective of the oil
and solid type and concentration. Direct and indirect heating of
the different medias are provided using a variety of chemical and
chemical free treatment liquid wash and thermal processes to effect
separation of bitumen oil from the solids. Such process strategy
provides for the treatment of all solid particle types, including
those particles of high surface activity consisting of silts and
clays, prone to adsorb and retain oil contamination. Treatment and
disposal of the fines are provided in the process contemplated,
maximizing the recovery of bitumen.
[0040] There are no moving parts contacting the slurry, making this
process less mechanically intensive and subsequently more
economical to operate from a O&M standpoint, compared to other
bitumen recovery processes. Each step of the method is configured
and optimized to separate bitumen with the end process being
bitumen recovery.
[0041] The method has application in the processing of tar sands,
production sand, drill cuttings derived from bitumen laden
geological formations using water based drill fluids, contaminated
oily sand or gravel, and contaminated soil.
[0042] Immaterial modifications may be made to the embodiments
disclosed here without departing from the invention.
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