U.S. patent application number 10/738089 was filed with the patent office on 2005-06-23 for mine site oil sands processing.
Invention is credited to Coward, Juhan, Cymerman, George, McTurk, Jim.
Application Number | 20050134102 10/738089 |
Document ID | / |
Family ID | 34808906 |
Filed Date | 2005-06-23 |
United States Patent
Application |
20050134102 |
Kind Code |
A1 |
Cymerman, George ; et
al. |
June 23, 2005 |
Mine site oil sands processing
Abstract
A process line comprising a combination of mobile and
relocatable equipment units is provided at an oil sand mine site.
The process line may comprise: a mobile shovel; a mobile bin and
double roll crusher; a relocatable conveyor belt extending along
the mine face; a relocatable slurry preparation assembly, such as a
secondary crusher and jet pump; a pipeline; and a relocatable
desanding circuit of separators. The process line conducts the
following steps: mining the oil sand; crushing it to conveyable
size; conveying it to a slurry preparation location; further
crushing it to slurrying size and mixing it with heated water to
produce a pumpable, aerated oil sand slurry; transporting and
conditioning the slurry in the pipeline; desanding it to produce a
product comprising bitumen and water and tailings; depositing
tailings in a retention facility; and removing the product from the
mine site in a pipeline.
Inventors: |
Cymerman, George; (Edmonton,
CA) ; Coward, Juhan; (Edmonton, CA) ; McTurk,
Jim; (Fort McMurray, CA) |
Correspondence
Address: |
MILLEN, WHITE, ZELANO & BRANIGAN, P.C.
2200 CLARENDON BLVD.
SUITE 1400
ARLINGTON
VA
22201
US
|
Family ID: |
34808906 |
Appl. No.: |
10/738089 |
Filed: |
December 18, 2003 |
Current U.S.
Class: |
299/7 |
Current CPC
Class: |
E02F 7/00 20130101; E02F
1/00 20130101; E21C 41/31 20130101; E21C 41/26 20130101 |
Class at
Publication: |
299/007 |
International
Class: |
E02F 007/00 |
Claims
1. A process line for producing an oil sand slurry at a mine site
having mineable oil sand, a mine face, a slurry preparation
location and a desanding location, comprising: mobile excavating
means for advancing along the mine face and excavating oil sand;
mobile sizing means for advancing along behind the excavating
means, receiving excavated oil sand and comminuting it to
conveyable size; relocatable first conveyor means for receiving the
oil sand from the sizing means, conveying it to the slurry
preparation location and delivering it thereto; relocatable slurry
preparation means, at the slurry preparation location, for
utilizing the oil sand delivered thereto, further comminuting it to
pumpable size and mixing it with heated water to produce a
pumpable, aerated, aqueous oil sand slurry; and first pipeline
means, connected with the slurry preparation means, for receiving
the slurry, transporting it while simultaneously conditioning it
and delivering it to the desanding location for desanding.
2. The process line as set forth in claim 1 wherein the first
conveyor means is a belt conveyor extending along the mine
face.
3. A process for producing an oil sand slurry at a mine site having
mineable oil sand, a mine face, a slurry preparation location and a
desanding location, comprising: excavating oil sand progressively
along the mine face; comminuting the oil sand to conveyable size;
conveying the comminuted oil sand along the mine face to the slurry
preparation location; mixing the oil sand with heated water at the
slurry preparation location and producing a pumpable, aerated,
aqueous oil sand slurry; and transporting the slurry through a
pipeline from the slurry preparation location to the desanding
location for desanding.
4. A process line for producing desanded product, comprising
bitumen and water, and tailings, comprising sand and water, at a
mine site having mineable oil sand, a mine face, a slurry
preparation location and a desanding location, comprising: mobile
excavating means for advancing along the mine face and excavating
oil sand; mobile sizing means for advancing along behind the
excavating means, receiving excavated oil sand and comminuting it
to conveyable size; relocatable first conveyor means for receiving
the oil sand from the sizing means, conveying it to the slurry
preparation location and delivering it thereto; relocatable slurry
preparation means, at the slurry preparation location, for
utilizing the oil sand delivered thereto, further comminuting it to
pumpable size and mixing it with heated water to produce a
pumpable, aerated, aqueous oil sand slurry containing liquid and
sand components; first pipeline means, connected with the slurry
preparation means, for receiving the slurry, transporting it while
simultaneously conditioning it and delivering it to the desanding
location; and relocatable desanding means, at the desanding
location and connected with the first pipeline means, for receiving
the slurry and separating liquid and sand components of the slurry
to produce separate streams of desanded product and tailings.
5. The process line as set forth in claim 4 comprising: a product
pipeline, connected with the desanding means, for transporting the
desanded product stream from the mine site.
6. The process line as set forth in claim 5 wherein the mine site
has a tailings retention facility and comprising: means, connected
with the desanding means, for depositing tailings at the retention
facility.
7. The process line as set forth in claim wherein the desanding
means comprises: a series of countercurrently operating separators
for progressively treating slurry to separate bitumen from
sand.
8. The process line as set forth in claim wherein: the first
conveyor means extends along the mine face; and the desanding means
comprises a series of countercurrently operating separators for
progressively treating slurry to separate bitumen from sand.
9. A process for producing desanded product, comprising bitumen and
water, and tailings, comprising sand and water, at a mine site
having mineable oil sand, a mine face, a slurry preparation
location and a desanding location, comprising: excavating oil sand
progressively along the mine face; comminuting the oil sand to
conveyable size; conveying the comminuted oil sand along the mine
face to the slurry preparation location; mixing the oil sand with
heated water at the slurry preparation location and producing a
pumpable, aerated, aqueous oil sand slurry having bitumen and sand
components; transporting the slurry through a pipeline from the
slurry preparation location to the desanding location; and
separating bitumen and sand components of the slurry to produce
separate desanded product and tailings.
10. The process as set forth in claim 9 wherein: the mine site has
a tailings retention facility, and comprising: transporting the
desanded product from the mine site in a pipeline; and depositing
tailings in the retention facility.
11. The process line of claim 1, wherein: the sizing means
comprises a first surge bin for receiving and dispensing excavated
oil sand, a first double roll crusher for comminuting the dispensed
oil sand and means for conveying the dispensed oil sand from the
screen means to the crusher.
12. The process line of claim 1, wherein: the slurry preparation
means comprises a second surge means for receiving and dispensing
oil sand from the first conveyor means, a second double roll
crusher for comminuting the oil sand, means for conveying oil sand
from the second surge means to the second double roll crusher, a
jet pump for mixing the oil sand with heated water, a hopper for
feeding the oil sand to the jet pump, means for conveying oil sand
from the second double roll crusher to the hopper and means for
supplying heated water to the jet pump.
13. A process line for producing an oil sand slurry at a mine site
having mineable oil sand, a mine face, a slurry preparation
location and a desanding location, comprising: mobile excavating
means for advancing along the mine face and excavating oil sand;
mobile sizing means for advancing along behind the excavating
means, receiving excavated oil sand and comminuting it to
conveyable size; relocatable first conveyor means for receiving the
oil sand from the sizing means, conveying it to the slurry
preparation location and delivering it thereto; relocatable slurry
preparation means, at the slurry preparation location, for
utilizing the oil sand delivered thereto and mixing it with heated
water to produce a pumpable, aerated, aqueous oil sand slurry; and
first pipeline means, connected with the slurry preparation means,
for receiving the slurry, transporting it while simultaneously
conditioning it and delivering it to the desanding location for
desanding;
14. The process line of claim 13 wherein the first conveyor means
is a belt conveyor extending along the mine face.
15. The process line of claim 13 wherein: the slurry preparation
means comprises a rotary digester, means for receiving oil sand
from the first conveyor means and feeding it to the rotary digester
and means for supplying heated water to the rotary digester.
16. A process line for producing desanded product, comprising
bitumen and water, and tailings, comprising sand and water, at a
mine site having mineable oil sand, a mine face, a slurry
preparation location and a desanding location, comprising: mobile
excavating means for advancing along the mine face and excavating
oil sand; mobile sizing means for advancing along behind the
excavating means, receiving excavated oil sand and comminuting it
to conveyable size; relocatable first conveyor means for receiving
the oil sand from the sizing means, conveying it to the slurry
preparation location and delivering it thereto; relocatable slurry
preparation means, at the slurry preparation location, for
utilizing the oil sand delivered thereto and mixing it with heated
water to produce a pumpable, aerated, aqueous oil sand slurry;
first pipeline means, connected with the slurry preparation means,
for receiving the slurry, transporting it while simultaneously
conditioning it and delivering it to the desanding location; and
relocatable desanding means, at the desanding location and
connected with the first pipeline means, for receiving the slurry
and separating liquid and sand components of the slurry to produce
separate streams of desanded product and tailings.
17. The process line of claim 16 wherein the first conveyor means
is a belt conveyor extending along the mine face.
18. The process line of claim 16 wherein: the slurry preparation
means comprises a rotary digester, means for receiving oil sand
from the first conveyor means and feeding it to the rotary digester
and means for supplying heated water to the rotary digester.
19. The process line as set forth in claim 16, wherein the
desanding means comprises: a series of countercurrently operating
separators for progressively treating slurry to separate bitumen
from sand.
20. The process line as set forth in claim 13, comprising: a
product pipeline, connected with the desanding means, for
transporting the desanded product stream from the mine site.
21. The process line as set forth in claim 20 wherein the mine site
has a tailings retention facility and comprising: means, connected
with the desanding means, for depositing tailings at the retention
facility.
22. The process line as set forth in claim 7, wherein at least one
separator is a cycloseparator.
23. The process line as set forth in claim 7, wherein at least one
separator is an inclined plate settler.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a system, located at a mine
site, for mining oil sand, slurrying it and desanding the slurry to
produce a pipelineable stream of bitumen, fines and water.
BACKGROUND OF THE INVENTION
[0002] Oil sand from the Fort McMurray region of Alberta has now
been commercially surface mined and processed for about 40 years,
to extract and recover the contained bitumen.
[0003] The initial technique used can broadly be described as
follows:
[0004] excavating oil sand;
[0005] crushing the as-mined oil sand, which contains large lumps
and rocks, in stages, to a size which can be slurried and
pumped;
[0006] mixing the crushed oil sand with heated water and,
optionally, caustic or other process aids, to produce a slurry. In
the course of mixing and subsequent pipelining, lumps are ablated,
bitumen is liberated from the oil sand and is dispersed into the
water phase, air bubbles are entrained and bitumen droplets
coalesce and are aerated (the sum of these results is referred to
as `conditioning`);
[0007] temporarily retaining the conditioned slurry under quiescent
conditions in a large gravity separation vessel (referred to as the
`PSV`)--during this separation or flotation step, the sand settles
and is removed as an underflow, together with some bitumen and
water, and the aerated bitumen, contaminated with water and solids,
including fines, rises and is recovered as a froth;
[0008] optionally, withdrawing watery middlings from the PSV and
treating the middlings in induced air flotation cells to recover
contained bitumen as a contaminated froth while rejecting water and
solids as an underflow;
[0009] processing the PSV underflow to recover contained bitumen as
froth while rejecting water and solids (together with small amounts
of contained residual bitumen) as an underflow;
[0010] discarding the various water and solids underflows as
tailings into retention areas; and
[0011] combining and cleaning the froth streams in means such as
centrifuges to remove residual water and solids and produce
relatively clean bitumen ready for upgrading.
[0012] In selecting and developing the detailed steps, conditions
and equipment units that embody this broadly described system, it
needs to be appreciated that many factors have an influence in
arriving at the final implementation. Some of these factors
are:
[0013] The oil sand is erosive and tacky and the throughput of oil
sand is large. A typical circuit or process line, involving process
steps and equipment units, might process 8000 tonnes of oil sand
per hour. So the equipment used needs to facilitate processing this
scale of throughput of erosive, tacky material;
[0014] The oil sand contains clays that affect processing
detrimentally and the composition of the oil sand varies on an
on-going basis, particularly with respect to bitumen and clay
contents. It is therefore desirable to provide a system that is
amenable to oil sands blending;
[0015] The system involves a line of sequential equipment units and
steps. Therefore, periodic upsets along the processing line can
create problems both upstream and downstream. It follows that surge
capabilities and inventory supply along the line are therefore
desirable, together with the feasibility of bypassing units if
required;
[0016] The mining operations can be remote from the gravity
separation and cleaning process operations and this separation
usually increases steadily as mining proceeds. So a system adapted
to cope with on-going variation in separation is desirable;
[0017] The bitumen constitutes only a small fraction of the oil
sand. The main component is sand. The sand is, of course, without
value and thus there is incentive to separate it out of the slurry
at the first opportunity and deposit it as fill in the mine pit. So
a system which is amenable to this end is desirable; and
[0018] Of course it is desirable that the recovery of bitumen be
maximized and the loss of bitumen with the tailings minimized.
[0019] In the early embodiments of these facilities, the as-mined
oil sand was transported on belt conveyors from the mine sites to
central processing plants. However, the conveyors, often stretching
for miles, were expensive and difficult to operate. Later it was
found feasible to crush and mix the oil sand with heated water at
the mine site and then pump the resulting slurry through a pipeline
directly to a remote PSV. Today, this type of operation is being
implemented as new mining areas are developed. At the applicants'
facility, this scheme more specifically involves:
[0020] advancing a mobile shovel along the mine face to excavate
oil sand and load it into large trucks which haul the as-mined oil
sand some distance to a double roll crusher;
[0021] dumping the as-mined oil sand into a hopper feeding the
double roll crusher, which crushes the oil sand to conveyable size
(i.e. -24 inches);
[0022] delivering the crushed ore to a surge pile using a belt
conveyor;
[0023] gravity feeding oil sand from the surge pile to another belt
conveyor and delivering it to the top end of a mixer tower. The
mixer tower incorporates a downwardly descending arrangement of a
slurry mixer, a slurry screen and a pump box. In the course of
moving down through the tower elements, the oil sand is mixed with
heated water in the mixer to form the slurry and the slurry is then
screened to remove oversize. The screened slurry is received in the
pump box and the oversize is dumped on the ground for removal or is
transferred to a secondary tower where similar operations are
repeated on the oversize; and
[0024] then pumping the slurry in the pump box through a pipeline
to a PSV located at a processing plant remote from the mine
site.
[0025] However, the trucks constitute a significant portion of
material handling cost and the distance they must travel becomes
greater as the mine face moves away from the mixer tower.
[0026] Thus there exists a need for a different combination of
processing steps and equipment units, which eliminates or reduces
reliance on trucks and which can better cope with the gradual
advance of the mine face.
SUMMARY OF THE INVENTION
[0027] The phrase "mine site", as used herein, means an area of
land presently undergoing strip mining to excavate oil sand and
which has one or more mine faces and one or more tailings retention
facilities, which may be dike-enclosed areas or mined-out pits.
[0028] The adjective `mobile`, as used herein, is intended to
indicate that equipment is mounted on driven tracks or the like for
on-going advancement over terrain.
[0029] The adjective `relocatable`, as used herein, is intended to
indicate that equipment is of a transportable size and on skids or
the like, or can be readily disassembled into transportable
sections, whereby it is stationary when operating but it is
feasible to periodically move it from location to location, perhaps
every few months.
[0030] The term "unit", as used herein, is intended to mean a
single piece of equipment or an assembly of pieces of equipment,
which functions to perform one or more defined steps such as
crushing and/or mixing.
[0031] In accordance with one embodiment of the invention, a
process line comprising a combination of operatively connected
mobile and relocatable equipment units is provided at a mine site.
The process line functions to excavate oil sand and produce a
stream of pumpable, aerated, aqueous oil sand slurry. More
particularly, the process line comprises:
[0032] a mobile excavating means for advancing along a mine face
and excavating oil sand;
[0033] a mobile sizing means for advancing along behind the
excavating means, receiving the oil sand and comminuting it to
conveyable size;
[0034] a relocatable first conveyor means, preferably extending
along the mine face, for receiving the once comminuted oil sand
from the sizing means and conveying it to a slurry preparation
location;
[0035] a relocatable slurry preparation means, at said location,
for mixing the oil sand with heated water and producing a pumpable,
aerated, aqueous oil sand slurry; and
[0036] a first pipeline means for receiving the slurry and pumping
and transporting it while simultaneously conditioning it, whereby
said means produces a stream of slurry amenable for desanding and
delivers it to a desanding location.
[0037] In one preferred feature of this embodiment of the process
line, a lengthy first conveyor means, extending along the mine
face, permits the slurry preparation means to remain stationary for
a period of time, while coupling it for oil sand supply with the
mobile and advancing excavating and sizing means.
[0038] In another feature of this embodiment, the slurry is moved
through a pipeline, while on the mine site, to condition it in
preparation for desanding.
[0039] In another aspect of the described embodiment, a process is
provided comprising the steps of:
[0040] excavating oil sand progressively along a mine face;
[0041] comminuting the oil sand to conveyable size;
[0042] conveying the comminuted oil sand along the mine face to a
slurry preparation location on the mine site;
[0043] mixing the oil sand with heated water at the slurry
preparation location and producing a pumpable, aerated, aqueous oil
sand slurry; and
[0044] transporting the slurry through a pipeline from the slurry
preparation location to a desanding location.
[0045] In an optional extension of the previously described process
and process line, a relocatable desanding means is connected with
the first pipeline means at the desanding location. The desanding
means functions to receive the slurry and separate liquid and sand
components of the slurry. It produces a desanded product, mainly
consisting of bitumen, fines and water, and tailings, which mainly
consists of sand, fines and water.
[0046] The desanding means preferably comprises a circuit of
separators, arranged in series and operating countercurrently,
wherein the underflow (or heavy fraction output) of one separator
is fed to the next separator, the underflow of the last separator
is tailings and the overflow (or lighter fraction output) of the
first separator goes to a product pipeline, which transports it
from the mine site, while the overflow of each following separator
is recycled to the preceding separator.
[0047] It is a feature of the desanding circuit that subjecting
separator underflow to secondary separation improves the
probability of recovering contained bitumen.
[0048] The underflow of the last separator may be discarded into a
dike-enclosed retention area or mined-out pit or otherwise
processed as described below.
[0049] In a preferred embodiment, a plurality of such process lines
are employed at the same mine site. As a consequence it is possible
to transfer oil sand ore or slurry between process lines to cope
with upsets or equipment repairs.
DESCRIPTION OF THE DRAWINGS
[0050] FIG. 1 is a schematic showing the process line for
excavating, conveying and preparing a pipelineable slurry;
[0051] FIG. 2 is a schematic showing the process line at a mine
site having mineable oil sand and employing the steps of:
excavating oil sand; conveying it; mixing it with water to form a
slurry; transporting and conditioning the slurry; and desanding it
to produce desanded product and tailings;
[0052] FIG. 3 is a schematic similar to FIG. 2 but showing an
inclined settler substituted for a cycloseparator in the desanding
circuit;
[0053] FIG. 4 is a schematic showing a plurality of process lines
at a mine site, wherein in one process line a bucket wheel
excavator is substituted for a shovel, and further showing a
tailings retention facility and a thickener for concentrating fine
solids from the tailings;
[0054] FIG. 5 is a perspective view of a rotary digester, which may
be used in the process line to form the slurry;
[0055] FIG. 6 is a view similar to FIG. 5, showing part of the drum
wall broken away to display internal lifters;
[0056] FIG. 7 is a side view of a cycloseparator, which may be used
in the desanding circuit showing the internal section of the vortex
finder in dotted lines; and
[0057] FIG. 8 is a sectional side view showing an inclined
settler.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0058] A process line 1 in accordance with the invention comprises
a series of operatively connected processing units located at a
mine site 2. The mine site 2 is positioned on a body of mineable
oil sand 3, such as exists in the Fort McMurray region of Alberta.
The mine site 2 has one or more mine faces 4, a slurry preparation
location 5, a desanding location 6 and a tailings retention
facility 7. As the mine faces 4 advance, one or both of the
locations 5, 6 will periodically advance as well. As shown in FIG.
4, a plurality of process lines 1 may be in use on the mine site
2.
[0059] In the preferred embodiment (as shown in FIGS. 1 and 2),
each process line 1 comprises:
[0060] A mobile mining shovel 10, which is mounted on driven tracks
11. The shovel 10 is positioned at the mine face 4 for excavating
the oil sand 3. It is operative to advance along the mine face 4.
Otherwise stated, the shovel 10 provides mobile excavating means
for advancing along the mine face 4 and excavating oil sand 3;
[0061] A mobile sizing unit 12 which comprises a surge bin 13, an
apron feeder 16, a double roll crusher 14, and a conveyor and belt
wagon 15. The sizing unit 12 is mounted on one or more platforms
17, each supported on drive tracks 18.
[0062] In operation the shovel 10 dumps oil sand 3 into the surge
bin 13. The apron feeder 16 feeds oil sand 3 from the bin 13 to the
crusher 14. The crusher 14 comminutes the excavated oil sand 3 to a
size that is conveyable on a belt conveyor, for example to -24
inch. The feed conveyor 19 deposits the oil sand 3 onto the
conveyor and belt wagon 15 which feeds the adjacent mine face
conveyor belt 20.
[0063] In summary, the sizing unit 12 provides mobile sizing means
for advancing along behind the excavating means, receiving
excavated oil sand and comminuting it to conveyable size;
[0064] An elongate, relocatable conveyor belt 20 which extends
along the mine face 4. The conveyor belt 20 receives the oil sand 3
from the feed conveyor 19 and conveys it to a surge pile 21 located
at the slurry preparation location 5.
[0065] In summary, a relocatable first conveyor means receives the
oil sand 3 from the sizing means, conveys it to the slurry
preparation location 5 and delivers it thereto;
[0066] A relocatable slurry preparation unit 25 positioned at the
slurry preparation location 5. The unit 25 comprises the surge pile
21, a feed conveyor 26, a hopper 27, a feed conveyor 29, a double
roll crusher 30, a feed conveyor 31, a hopper 32, a jet pump 33 and
a source 34 of heated water.
[0067] In operation, oil sand 3 is fed from the surge pile 21 by
the feed conveyor 26 into the hopper 27 and fed by the conveyor 29
to the crusher 30. The sum of these actions is referred to
collectively as utilizing the oil sand. The crusher 30 comminutes
the oil sand to pumpable size, typically 4 inches. A conveyor 31
feeds the crushed oil sand 3 into the gravity feed hopper 32 of the
jet pump 33. The hopper 32 dispenses the oil sand 3 into the jet
pump 33, where it is entrained into a jet of motive heated water. A
source 34 supplies the water to the jet pump 33. The jet pump 33
mixes the oil sand 3 and water, while entraining air, to produce a
pumpable, aerated, aqueous oil sand slurry 35.
[0068] In summary, there is provided relocatable slurry preparation
means, at the slurry preparation location 5, for utilizing the oil
sand 3 delivered thereto, further comminuting it to pumpable size
and mixing it with heated water to produce a pumpable, aerated,
aqueous oil sand slurry 35;
[0069] A slurry pipeline 40 which is connected with the outlet of
the jet pump 33 and extends to the desanding location 41. The
pipeline 40 may include one or more slurry pumps 42.
[0070] In the course of being pumped through the pipeline 40, the
slurry stream 35 is mixed and conditioned.
[0071] In summary, there is provided a first pipeline means,
connected with the slurry preparation means, for receiving the
slurry 35, transporting it while simultaneously conditioning it,
and delivering it to the desanding location 6 for desanding;
[0072] A relocatable desanding circuit 43, which is positioned at
the desanding location 6 and is connected with the downstream end
of the slurry pipeline 40.
[0073] The desanding circuit 43 comprises a series of
countercurrently operating separators. More particularly, the
separators used are centrifugal cycloseparators 44, 45, 46, one of
which is shown in FIG. 7. The cycloseparators 44, 45, 46 are,
respectively, generally cylindrical, hollow vessels 47,48, 49
having internal chambers 50, 51, 52, tangential inlets 53, 54, 55
at the upstream end and central vortex finder outlets 56, 57, 58
and peripheral outlets 59, 60, 61 at the downstream ends.
[0074] The slurry stream 35 is pumped from the pipeline 40 into the
tangential inlet 53 of the first cycloseparator 44 (shown in FIG.
2). The slurry spins as it advances longitudinally through the
vessel chamber 50. The heavier fraction (mainly sand, fines and
some water and bitumen) concentrates outwardly and leaves the
vessel chamber 50 as an underflow stream 62 through the peripheral
outlet 59. The lighter fraction (mainly bitumen, fines and water)
concentrates inwardly and leaves the vessel chamber 50 as a central
overflow stream 63 through the vortex finder outlet 56. The first
separator overflow stream 63 is fed as desanded product to a
product pipeline 65 which transports it from the mine site 2 to a
remote processing plant (not shown). The first separator underflow
stream 62 is fed through outlet 59 and line 66 to the inlet 54 of
the second separator 45. The same type of centrifugal separation
occurs in the second separator chamber 51. The overflow stream 67
from the second separator chamber 51 is recycled through line 68 to
the inlet 53 of the first cycloseparator 44. The underflow stream
69 from the second cycloseparator 45 is fed through the line 70 to
the inlet 55 of the third cycloseparator 46. Water may also be
added as required through line 71 to the inlet 55 of the third
cycloseparator 46, as the underflow stream, 69 may need dilution.
The overflow stream 72 from the third cycloseparator 46 is recycled
through line 73 to the inlet 54 of the second cycloseparator 45.
The underflow stream 74 from the third cycloseparator 46 is removed
through the line 75 as tailings.
[0075] In summary, there is provided relocatable desanding means,
at the desanding location and connected with the first pipeline
means, for receiving the slurry and separating liquid and sand
components of the slurry to produce separate streams of desanded
product and tailings;
[0076] Means are provided for depositing the tailings at the
retention facility 7 (see FIG. 4). In the preferred embodiment, a
mobile boom 80, carrying a cyclone 81 at its upper end, is
positioned alongside the retention facility. The line 74 feeds the
stream 74 of tailings to the cyclone 81, which separates the
tailings components to produce an underflow stream 82, mainly
comprising sand and some water, and an overflow stream 83, mainly
comprising water and fine solids (clay). The underflow stream 82 is
deposited on the beach 84 of the retention facility 7. The overflow
stream 83 is conveyed through a line 85 to a thickener 86. The
thickener 86 separates the cyclone overflow components to produce a
paste-like underflow stream 87, which is deposited in the mined out
pit, and a water stream 88 which may be recycled to the desanding
circuit 43.
[0077] Variants
[0078] It is to be understood that applicants contemplate that a
person skilled in the art may substitute units without
significantly affecting the way in which the process line 1
works.
[0079] For example:
[0080] A bucketwheel excavator 90, shown in FIG. 4, may be
substituted for the shovel 10;
[0081] A rotary digester 91, shown in FIGS. 5, 6, may be
substituted for the jet pump 33. The digester 91 is capable of
processing larger lumps of oil sand and thus may not require a
secondary crusher 30.
[0082] The digester 91 is a rotatable drum 92 having internal
lifters 93, drive means 94 and a trommel screen 95. The oil sand
and water are fed into a feed box 96 and are tumbled within the
drum 92 to mix them and condition the produced slurry. The screen
95 removes oversize and the screened slurry is pumped through
pipeline 40 by pump 97; and
[0083] an inclined plate separator 100, shown in FIG. 8, may be
substituted for a cycloseparator.
[0084] The slurry is fed into the bottom inlet 99 of the separator
100 from pipeline 40. The sand separates and drops along the
internal plates 101 and is withdrawn through the outlet 102. The
water, some bitumen and fine solids leave through the top outlet
103.
[0085] The scope of the invention is defined by the claims now
following.
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