U.S. patent application number 14/115713 was filed with the patent office on 2014-03-20 for heat and water integration process for an oil sand operation with direct steam injection of warm thickener overlfow.
This patent application is currently assigned to FORT HILLS ENERGY L.P.. The applicant listed for this patent is Blair James Penner, Shawn Van Der Merwe. Invention is credited to Blair James Penner, Shawn Van Der Merwe.
Application Number | 20140076785 14/115713 |
Document ID | / |
Family ID | 47215846 |
Filed Date | 2014-03-20 |
United States Patent
Application |
20140076785 |
Kind Code |
A1 |
Penner; Blair James ; et
al. |
March 20, 2014 |
HEAT AND WATER INTEGRATION PROCESS FOR AN OIL SAND OPERATION WITH
DIRECT STEAM INJECTION OF WARM THICKENER OVERLFOW
Abstract
A heat and water integration process for an oil sands operation
includes subjecting warm oil sands tailings to thickening to
produce thickened tailings and warm water overflow; subjecting the
warm water overflow to direct steam injection (DSI) to produce
steam heated thickener water; providing the steam heated thickener
water to a unit of the oil sand operation; and producing the warm
oil sands tailings from the oil sands operation. The oil sand
operation unit may be an oil sand ore preparation unit and/or a
primary separation unit, for example. The heated thickener water
can replace water taken from pond inventories. The DSI may use
excess, low quality, wet, low pressure and/or blow-down steam. The
process enables improved heat and water usage in oil sands
processing.
Inventors: |
Penner; Blair James;
(Calgary, CA) ; Van Der Merwe; Shawn; (Calgary,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Penner; Blair James
Van Der Merwe; Shawn |
Calgary
Calgary |
|
CA
CA |
|
|
Assignee: |
FORT HILLS ENERGY L.P.
Calgary
AB
|
Family ID: |
47215846 |
Appl. No.: |
14/115713 |
Filed: |
May 2, 2012 |
PCT Filed: |
May 2, 2012 |
PCT NO: |
PCT/CA2012/050287 |
371 Date: |
November 5, 2013 |
Current U.S.
Class: |
208/391 |
Current CPC
Class: |
B03D 2203/006 20130101;
C10G 1/045 20130101; B01D 21/267 20130101; C10G 1/047 20130101 |
Class at
Publication: |
208/391 |
International
Class: |
C10G 1/04 20060101
C10G001/04 |
Foreign Application Data
Date |
Code |
Application Number |
May 20, 2011 |
CA |
274823 |
Claims
1. A heat and water integration process for an oil sands operation,
comprising: subjecting a warm oil sands tailings stream to
thickening to produce a thickened tailings component and a warm
water overflow component; subjecting at least a portion of the warm
water overflow component to direct steam injection to produce a
steam heated thickener water; providing the steam heated thickener
water to a unit of the oil sand operation; and producing the warm
oil sands tailings from the oil sands operation.
2. The heat and water integration process of claim 1, wherein the
unit of the oil sand operation is selected from (i) an oil sand ore
preparation unit and (ii) a primary separation unit.
3. The heat and water integration process of claim 2, wherein the
primary separation unit receives an oil sand slurry and froth for
separation and at least a portion of the steam heated thickener
water is used as froth under-wash in the primary separation
unit.
4. The heat and water integration process of claim 2, wherein the
oil sand ore preparation unit receives oil sand ore and at least a
portion of the steam heated thickener water is used as hot
slurrying medium in the oil sand ore preparation unit.
5. The heat and water integration process of claim 1, comprising
supplying ambient recycle water from a pond to the unit of the oil
sands operation.
6. The heat and water integration process of claim 5, comprising
combining a portion of the ambient recycle water with a portion of
the warm water overflow component to produce a warm process water
stream and supplying the warm process water stream to an oil sand
ore preparation unit.
7. The heat and water integration process of claim 5, comprising
heating a portion of the ambient recycle water in a heat exchanger
to produce a heated recycle water and supplying the heated process
water to an oil sand ore preparation unit.
8. The heat and water integration process of claim 5, comprising
heating a portion of the ambient recycle water in a heat exchanger
to produce a heated recycle water and supplying the heated process
water to a primary separation unit.
9. The heat and water integration process of claim 8, wherein the
wherein the primary separation unit receives an oil sand slurry and
froth for separation and at least a portion of the steam heated
thickener water and the heated recycle water are combined and used
as froth under-wash in the primary separation unit.
10. The heat and water integration process of claim 7, comprising:
providing steam from a central steam source; using a first portion
of the steam in the direct steam injection; and using a second
portion of the steam for heating the ambient recycle water in the
heat exchanger.
11. The heat and water integration process of claim 5, wherein the
warm water overflow component has a temperature between about
20.degree. C. and about 45.degree. C. higher than the recycle pond
water.
12. The heat and water integration process of claim 1, wherein the
direct steam injection heats the warm water overflow component from
an initial temperature between about 20.degree. C. and about
50.degree. C. to a temperature of the steam heated thickener
overflow between about 70.degree. C. and about 90.degree. C.
13. The heat and water integration process of claim 12, wherein the
temperature of the steam heated thickener overflow is between about
75.degree. C. and about 85.degree. C.
14. The heat and water integration process of any one of claims 1
to 13, wherein the direct steam injection has a steam input between
about 20 to 90 kG/t of oilsand.
15. The heat and water integration process of claim 14, wherein the
steam input is between about 150 tonnes/hr and about 300
tonnes/hr.
16. The heat and water integration process of claim 1, wherein the
direction steam injection comprises maintaining sufficient
backpressure on the steam heated thickener water downstream of the
direction steam injection so as to sub-cool the warm water overflow
component.
17. The heat and water integration process of claim 1, wherein the
direction steam injection uses steam selected from the group
consisting of excess steam, low quality steam, wet steam, low
pressure steam and blow-down steam.
18. The heat and water integration process of claim 1, wherein the
direction steam injection uses steam having a pressure at least 45
psia.
19. The heat and water integration process of claim 1, wherein the
direction steam injection uses steam containing non-condensable
gases.
20. The heat and water integration process of claim 1, wherein the
direction steam injection uses saturated steam.
21. The heat and water integration process of claim 1, wherein the
direction steam injection uses steam generated by a low pressure
boiler.
22. The heat and water integration process of claim 1, wherein the
direction steam injection uses steam generated from condensate
blowdown.
23. The heat and water integration process of claim 1, comprising
providing a knock-out or steam trap system upstream of the
direction steam injection.
24. The heat and water integration process of claim 1, wherein the
process is conducted at least in wintertime.
25. A process for producing bitumen, comprising: subjecting oil
sands ore to extraction operations using hot extraction water, in
order to produce bitumen and a warm oil sands tailings stream;
subjecting the warm oil sands tailings stream to thickening to
produce a thickened tailings component and a warm water overflow
component; subjecting at least a portion of the warm water overflow
component to direct steam injection to produce a steam heated
thickener water; and providing the steam heated thickener water to
the extraction operations as part of the hot extraction water.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to the field of oil
sands processing and in particular relates to a heat and water
integration process for reuse of hot thickener overflow water.
BACKGROUND
[0002] Oil sands processing requires hot water for a number of unit
operations. In particular, oil sands ore preparation and primary
separation cells require hot water.
[0003] It is known to recuperate water from fresh river sources or
from large ponds used to store water previously used and affected
by the oil sands processing. The recycle pond water can be heated
and used in oil sands extraction operations, for example.
[0004] However, recycle process water contains a number of
contaminants such as residual bitumen, suspended mineral solids and
various salts. Due to the composition of recycle process water,
heating in conventional indirect heating devices--such as shell and
tube or plate heat exchangers--results in fouling of heat transfer
surfaces. One known mitigation measure to combat this fouling is to
install exchanger areas to facilitate maintenance and cleaning of
heat transfer areas.
[0005] Thickeners are used in oil sands extraction and froth
treatment operations to increase the solids concentration of an
input stream and produce overflow water. Thickener overflow water
has been considered for reuse in upstream extraction processes
after being heated to desired temperatures. However, as thickeners
are prone to upsets, the variable composition of thickener overflow
leads to fouling of heat exchanger transfer areas. Thickener water
is viewed as having low quality heat making it unsuitable for many
applications in oil sands processing.
[0006] Direct steam injection is also known for heating bitumen
froth prior to froth treatment, as disclosed in Canadian patent No.
2,455,011 (Gaston et al.).
[0007] However, it has been generally viewed that direct steam
injection is not suitable for several heating applications since
the steam/condensate are lost to the process fluid, thus requiring
higher upstream make-up water and water treatment requirements to
compensate for the lost steam/condensate. This is particularly the
case for steam generation systems that produce high quality steam,
e.g. over 600 psia, for steam/power cogeneration applications. In
these high quality steam generation systems, it is important to
recycle a maximum amount of condensate for reuse as steam to
maintain economic feasibility and such high quality
steam/condensate is not misused for general stream heating.
[0008] In summary, known practices and techniques for providing hot
water to oil sands operations have various drawbacks and
inefficiencies, and there is indeed a need for a technology that
overcomes at least some of those drawbacks and inefficiencies.
SUMMARY OF THE INVENTION
[0009] The present invention responds to the above-mentioned need
by providing a process for heat and water integration of an oil
sands extraction and bitumen production operation.
[0010] In one embodiment, the invention provides a heat and water
integration process for an oil sands operation, comprising: [0011]
subjecting a warm oil sands tailings stream to thickening to
produce a thickened tailings component and a warm water overflow
component; [0012] subjecting at least a portion of the warm water
overflow component to direct steam injection to produce a steam
heated thickener water; [0013] providing the steam heated thickener
water to a unit of the oil sand operation; and [0014] producing the
warm oil sands tailings from the oil sands operation.
[0015] In one aspect, the unit of the oil sand operation is
selected from (i) an oil sand ore preparation unit and (ii) a
primary separation unit.
[0016] In another optional aspect, the primary separation unit
receives an oil sand slurry and froth for separation and at least a
portion of the steam heated thickener water is used as froth
under-wash in the primary separation unit.
[0017] In another optional aspect, the oil sand ore preparation
unit receives oil sand ore and at least a portion of the steam
heated thickener water is used as hot slurrying medium in the oil
sand ore preparation unit.
[0018] In another optional aspect, the process includes supplying
ambient recycle water from a pond to the unit of the oil sands
operation.
[0019] In another optional aspect, the process includes combining a
portion of the ambient recycle water with a portion of the warm
water overflow component to produce a warm process water stream and
supplying the warm process water stream to an oil sand ore
preparation unit.
[0020] In another optional aspect, the process includes heating a
portion of the ambient recycle water in a heat exchanger to produce
a heated recycle water and supplying the heated process water to an
oil sand ore preparation unit.
[0021] In another optional aspect, the process includes heating a
portion of the ambient recycle water in a heat exchanger to produce
a heated recycle water and supplying the heated process water to a
primary separation unit.
[0022] In another optional aspect, the primary separation unit
receives an oil sand slurry and froth for separation and at least a
portion of the steam heated thickener water and the heated recycle
water are combined and used as froth under-wash in the primary
separation unit.
[0023] In another optional aspect, the process includes providing
steam from a central steam source; using a first portion of the
steam in the direct steam injection; and using a second portion of
the steam for heating the ambient recycle water in the heat
exchanger.
[0024] In another optional aspect, the warm water overflow
component has a temperature between about 20.degree. C. and about
45.degree. C. higher than the recycle pond water.
[0025] In another optional aspect, the direct steam injection heats
the warm water overflow component from an initial temperature
between about 20.degree. C. and about 50.degree. C. to a
temperature of the steam heated thickener overflow between about
70.degree. C. and about 90.degree. C.
[0026] In another optional aspect, the temperature of the steam
heated thickener overflow is between about 75.degree. C. and about
85.degree. C.
[0027] In another optional aspect, the direct steam injection has a
steam input between about 20 to 90 kG/t of oilsand.
[0028] In another optional aspect, the steam input is between about
150 tonnes/hr and about 300 tonnes/hr.
[0029] In another optional aspect, the direction steam injection
comprises maintaining sufficient backpressure on the steam heated
thickener water downstream of the direction steam injection so as
to sub-cool the warm water overflow component.
[0030] In another optional aspect, the direction steam injection
uses steam selected from the group consisting of excess steam, low
quality steam, wet steam, low pressure steam and blow-down
steam.
[0031] In another optional aspect, the direction steam injection
uses steam having a pressure at least 45 psia.
[0032] In another optional aspect, the direction steam injection
uses steam containing non-condensable gases.
[0033] In another optional aspect, the direction steam injection
uses saturated steam.
[0034] In another optional aspect, the direction steam injection
uses steam generated by a low pressure boiler.
[0035] In another optional aspect, the direction steam injection
uses steam generated from condensate blowdown.
[0036] In another optional aspect, the process includes providing a
knock-out or steam trap system upstream of the direction steam
injection.
[0037] In another optional aspect, the process is conducted at
least in wintertime.
[0038] The invention also provides a system for implementing the
process and its embodiments as described above and herein. The
system includes a thickener that produces a thickened tailings
component and a warm water overflow component, a direct steam
injection device for subjecting at least a portion of the warm
water overflow component to direct steam injection to produce a
steam heated thickener water; a unit of the oil sand operation for
receiving at least part of the steam heated thickener water.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a process flow diagram of a bitumen production
operation with direct steam injection (DSI) for hot thickener
water.
[0040] FIG. 2 is a process flow diagram of a bitumen extraction
operation with hot thickener water DSI heating and integration.
[0041] FIG. 3 is a process flow diagram of a froth treatment
operation with a thickener for the froth treatment tailings.
DETAILED DESCRIPTION
[0042] FIG. 1 illustrates an embodiment of the process of the
present invention. In this embodiment, a bitumen production
operation 10 receives oil sand 12 and produces a bitumen product
14. The bitumen production operation 10 also receives other process
streams and produces output streams. One output stream is a warm
tailings stream 16, which contains mineral solids such as sand,
silt and clay, residual bitumen and components thereof and water in
varying proportions depending on the particular source and
processing conditions that generated the tailings.
[0043] In one aspect, the warm tailings stream 16 is produced by a
tailings solvent recovery unit (TSRU) for treating the solvent
diluted tailings from a bitumen froth separation unit (FSU). The
TSRU recovers the solvent from the solvent diluted tailings and
generates TSRU tailings. In another optional aspect, the warm
tailings stream 16 is derived from middlings and/or bottoms of a
primary separation vessel (PSV). More regarding the source of the
warm tailings stream 16 and related reutilization of water and heat
will be discussed further herein-below.
[0044] Referring to FIGS. 1 and 2, the warm tailings stream 16 is
supplied to a thickener 18 for producing a thickener underflow
component 20 and a warm water overflow component 22. The thickener
18 may have a variety of constructions and structural or
operational aspects to achieve the separation. In one operational
aspect, the thickener is as generally described in Canadian patent
application No. 2,454,942 (Hyndman et al.), though it may
alternatively have various other constructions. The thickener may
produce only the thickener underflow component 20 and the warm
water overflow component 22 or it may have other outlets for
producing additional streams such as a recovered hydrocarbon stream
(not illustrated).
[0045] The thickener underflow component 20 may then be provided to
a tailings disposal equipment or piping 24 and eventually be fed to
a tailings pond.
[0046] The warm water overflow component 22 is subjected to direct
steam injection (DSI) 26 to produce steam heated process water 28.
The steam heated process water 28 can then be used in the bitumen
production operation 10.
[0047] FIG. 1 illustrates an embodiment wherein the DSI 26 is used
to heat thickener overflow water 22 by direct steam injection and
the steam heated process water 28 is used as hot process water
within the bitumen production process area.
[0048] FIG. 2 illustrates an embodiment wherein the DSI 26 is used
to heat thickener overflow water 22 by direct steam injection and
the steam heated process water 28 is used as hot process water in
an ore preparation area and as froth wash water in a primary
separation vessel (PSV).
[0049] It is noted that the figures do not show miscellaneous
extraction process water connections for mixing, flushing, etc.,
which are present in a bitumen extraction operation.
[0050] Referring to FIG. 2, the oil sand 12 is mixed with hot
process water 30 which may contain excess steam heated thickener
overflow 28 to form oil sand slurry 32 that is conditioned, i.e.
liberates the bitumen from the sand in a conditioning slurry
pipeline. It is noted that other names such as hydro-transport
slurry pipeline are used in literature. In the illustrated
embodiment, flotation froth 34 from a downstream unit is injected
into the conditioned oil sand slurry 32 upstream of the separation
cell 35 (also referred to as a "primary separation vessel (PSV)"
and "sep cell" herein). An amount of the steam heated process water
28 may be added to the sep cell as froth under-wash 36 to improve
the froth quality by washing and heating the bitumen froth as it
rises through a hot water layer. In order to stabilize the hot
water layer within the sep cell, the water temperature is higher
than the feed slurry, preferably 10.degree. C. higher and still
preferably 20.degree. C. higher. The sep cell 35 produces a bitumen
froth overflow 38 that is transferred to froth treatment 39. Note
that the bitumen production module 10 of FIG. 1 encompasses froth
treatment in which steam is a utility.
[0051] Referring to FIG. 2, the sep cell 35 also produces a
middlings stream 40 and a bottoms stream 42. Preferably, the
middlings stream 40 is subjected to middling flotation 44 to
produce flotation tailings 48 and middling flotation froth 46 to
make up part of the flotation froth 34. The middling floatation 44
may be conventional or column floatation.
[0052] The sep cell bottoms tailings 42 are combined with the
middling flotation tailings 48 and the combined stream 50 is fed to
a tailings cyclones 52. Cyclone overflow 54 is processed by final
flotation 56 (either conventional or column) to recover the
remaining portion 58 to make up the flotation froth 34.
[0053] In one aspect, the warm tailings stream 16 is at least
partially produced as underflow from the final floatation unit 56
which treats derivative middlings and bottoms streams from the sep
cell 35. The warm tailings stream 16 is processed by one or more
thickeners 18 for water and heat recovery.
[0054] The thickeners 18 may also recover water from other warm
tailings streams including froth treatment tailings (also referred
to as TSRU tailings). A portion of recovered thickener water 22 is
DSI heated and used where possible to minimize heat and water
requirements from cold recycle water and indirect steam heat
exchangers. The steam heated thickener water 28 is employed as warm
process water in extraction for flushing and other process
operations.
[0055] Still referring to FIG. 2, the thickened tailings 20 from
the thickener 18 are combined with cyclone tailings 60 as overall
extraction tailings 62 that are transferred to the tailing disposal
area 24. Tailing water 64 is collected in a tailings pond 66 where
suspended minerals settle and the tailings water cools to ambient
conditions for reuse in bitumen extraction as recycle water 68.
[0056] Recycle water 68 is returned to extraction for general use
as extraction water 70 (generally cold for flush purposes) and
heated by steam heat exchangers 72 for use as hot process water 30
in ore preparation and optionally as part of the froth underwash
water 36. The steam heat exchangers 72 use natural gas 74 or other
fuel sources supplied to steam boilers 76. A water treatment plant
78 treats water make-up 80, typically river water, to produce
treated water 82, so as to maintain condensate inventory for steam
production. Condensate 84 from the steam heat exchangers 72 is
recycled to steam boilers 76 to produce steam 86.
[0057] In one preferred aspect of the present invention, the steam
used for the DSI is selected from excess, low quality, wet, low
pressure or blow-down steam. For instance, low quality, wet or low
pressure steam which are not suited to many oil sand processing
applications may be advantageously used for heating the thickener
overflow water to produce steam heated thickener water which has
high quality heat for reuse in extraction or production processes.
In addition, in large oil sand processing facilities in which large
amounts of steam are generated, there is a corresponding large
amount of condensate generated and blowdown is periodically
required. This excess blowdown condensate may be used to generate
steam for thickener water DSI effectively dumping the blowdown
condensate into the thickener water. Furthermore, the steam may be
generated by retrofitting a plant with a low pressure boiler or the
like along with a thickener for recovering heat and water from the
oil sand processing operation for recycling. Retrofitting oil sand
plants with a boiler and thickener enables the water recovered as
thickener overflow to offset the water lost as condensate in DSI,
in addition to the low quality heat recovery from the thickener.
Understanding of the overall plant allows matching appropriate
steam and condensate streams with the DSI heating of thickener
overflow water. In some embodiments, condensate that would
otherwise be dumped is recycled as steam into the thickener water
for heating and reuse in oil sand processing operations. In one
aspect, the DSI steam used for thickener water heating has a
temperature between 140 to 215.degree. C. and a pressure between 50
and 400 psia and may contain non-condensable gases such as carbon
dioxide, air and the like that may be purged to maintain condensing
steam heat exchangers. There may be a knock-out or steam trap
system (not illustrated) just upstream of the DSI unit. The
knock-out or steam trap system may be used to remove water from the
steam, for example when above 10-15% water, and the removed water
may be recycled back into the process.
[0058] The excess thickener overflow water 22 is thus heated by DSI
units 26 that may be operated in series or parallel. The
arrangement of series or parallel DSI permits selective heating of
excess thickener water to match specific temperature requirements
for the end use of the steam heated process water. For example, the
steam heated thickener water 28 supplied as froth under-wash 36
would be heated to the temperature needed for cleaning/heating the
froth 34 separated in the sep cell 35.
[0059] For DSI operations, the water treatment capacity to supply
treated water 80 is increased to reflect the lost condensate
associated with the portion of the steam injected as direct
injection steam 88 into the DSI units.
[0060] The DSI heating of thickener overflow water for reuse in the
oil sand extraction or bitumen production operation reduces capital
as DSI unit have a lower cost compared to exchangers, improves
reliability for instance due to no fouling of exchanger surfaces
and recovery of both heat and water via the thickener. Thickeners
are prone to upsets leading to thickener water with variable
compositions which can cause abrupt increases in solids or
hydrocarbon content causing fouling of heat exchanger surfaces. DSI
allows robust heating of thickener overflow water to replace or
offset conventional heat exchanged hot process water from recycle
pond water. In addition, the thickener water is provided about
20.degree. C. to about 45.degree. C. hotter than the ambient
temperature of recycle water, since tailings ponds cool tailings
water while allowing suspended solids to settle out to mature fine
tailings. It is also noted that overflow water from thickeners are
further advantageous in this respect since the flow rates of the
thickener overflow streams is sufficiently moderate that the
increase make-up water required for the DSI heating is exceeded by
the cost and efficiency savings achieved by the process of the
present invention. Large volumes of water to be DSI heated would
experience erosion of the cost advantage due to the increased
make-up water to produce steam. It is also noted that, in one
aspect, the thicker overflow DSI heating complements existing
exchanger heating arrangements since the quantity of water produced
by the thickener normally will not replace all the exchangers.
Thus, there is a combination of DSI and exchanger heaters for
providing the hot water requirements to the bitumen production and
oil sand extraction operations. This equipment mix also provides
mutual redundancy.
[0061] In another optional aspect, the water make-up 80 may be
supplied from the recycle water system which would thus provide a
closed loop on water usage, i.e. no net water import to the
system.
[0062] It is also noted that the DSI heating may be conducted in a
manner as disclosed in Canadian patent application No. 2,735,311
(van der Merwe).
[0063] DSI units also rely on steam at pressures above the water
pressure. Where this steam is produced by boilers that require high
quality condensate for reliable operation, steam production is
associated with significant utility infrastructure for the recovery
of steam condensate and make-up water treatment. As DSI units can
utilize purged steam with non-condensables without infrastructure
to return condensate, the DSI provides an alternate process method
for recovery and reuse of the energy in low quality steam and
minimize costs associated with infrastructure.
[0064] Referring now to FIG. 3, in another embodiment, the
thickener 18' may be associated with a froth treatment operation 39
to thicken froth treatment tailings. The bitumen froth 38 is fed to
a dearator 89 and then to primary and secondary stage froth
separation units 90, 92 which are arranged in a counter-current
configuration. Fresh solvent 94 which may be paraffinic or
naphthenic is added to the second stage froth separation unit 92.
The high diluted bitumen 96 is treated in a solvent recovery unit
which may include two flash vessels 98, 100 to produce recovered
solvent 102 and solvent recovered bitumen 104. The second stage
froth separation unit 92 produces an underflow 106 that is solvent
diluted tailings which are treated in a tailings solvent recovery
unit which may include first and second stage flash or stripping
vessels 108, 110 to recover solvent stream 111. These stripping
vessels 108, 110 may be fed with steam 112. The solvent recovered
tailings 114 fro the second stage stripping vessel 110 may be
provided as the warm tailings stream 16 to the thickener 18'.
[0065] Engineering studies and calculations were effectuated for
average conditions to identify direct steam injection for thickener
overflow water for reducing energy in terms of steam requirements
to supply hot process water with a temperature of 85.degree. C.
which is typical for use in oil sands ore preparation. The steam
was considered with an enthalpy of 571 kJ/kg. Note that t/t refers
to metric tonnes per metric tonnes.
TABLE-US-00001 Process water recycled from tailings pond 0.792 t/t
oilsand Total Hot Process Water (HPW) for extraction 0.40 t/t
oilsand Warm Process Water recovered from thickener 0.48 t/t
oilsand Excess Warm Process Water (WPW) without DSI 0.085 t/t
oilsand HPW for froth under wash (FUW) 0.062 t/t oilsand Steam for
hot process water without DSI 575 kg/t oilsand Steam for FUW with
DSI 48 kg/t oilsand Total Steam for HPW with DSI to FUW 533 kg/t
oilsand
[0066] The analysis identified the application of DSI units for
heating warm process water recovered from extraction thickeners
reduces the energy required for processing oil sand and improves
the overall efficiency for bitumen extraction. It is noted that
this calculation data has not been optimized and it should be
understood that additional energy may be recovered in variants of
the present invention, for instance by finding additional uses for
the heated thickener water in other oil sands process units and
applications.
[0067] Finally, it should be understood that the present invention
is not limited to the embodiments, aspects, examples and
figures.
* * * * *