U.S. patent application number 14/871184 was filed with the patent office on 2016-04-28 for horizontal-flow oil sands separator for a solvent extraction process.
The applicant listed for this patent is Chien-Chiang Chen, Edward J. Grave, Paul D. Oldenburg, Andrew P. Steinhauser. Invention is credited to Chien-Chiang Chen, Edward J. Grave, Paul D. Oldenburg, Andrew P. Steinhauser.
Application Number | 20160115391 14/871184 |
Document ID | / |
Family ID | 54291722 |
Filed Date | 2016-04-28 |
United States Patent
Application |
20160115391 |
Kind Code |
A1 |
Steinhauser; Andrew P. ; et
al. |
April 28, 2016 |
Horizontal-Flow Oil Sands Separator for a Solvent Extraction
Process
Abstract
The disclosure includes techniques for recovering hydrocarbons
from a bituminous feed in a non-aqueous extraction process,
comprising a vessel that comprises a feed inlet on a proximate end
of the vessel, a feed outlet on a distal end of the vessel, a
bitumen outlet, and a plurality of hoppers, wherein each hopper
comprises a tailing outlet.
Inventors: |
Steinhauser; Andrew P.;
(Friendswood, TX) ; Grave; Edward J.; (Montgomery,
TX) ; Oldenburg; Paul D.; (Cypress, TX) ;
Chen; Chien-Chiang; (Spring, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Steinhauser; Andrew P.
Grave; Edward J.
Oldenburg; Paul D.
Chen; Chien-Chiang |
Friendswood
Montgomery
Cypress
Spring |
TX
TX
TX
TX |
US
US
US
US |
|
|
Family ID: |
54291722 |
Appl. No.: |
14/871184 |
Filed: |
September 30, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62067279 |
Oct 22, 2014 |
|
|
|
Current U.S.
Class: |
208/390 ;
196/14.52 |
Current CPC
Class: |
B01D 11/0242 20130101;
B01D 11/0284 20130101; C10G 1/04 20130101; B01D 11/00 20130101;
B01D 21/0003 20130101; B01D 21/10 20130101; B01D 11/0223 20130101;
B01D 21/34 20130101; C10G 1/045 20130101 |
International
Class: |
C10G 1/04 20060101
C10G001/04 |
Claims
1. A system for recovering hydrocarbons from a bituminous feed in
an oil sands solvent extraction process, comprising: a vessel
comprising: a feed inlet on a proximate end of the vessel; a feed
outlet on a distal end of the vessel; a bitumen outlet; and a
plurality of hoppers, wherein each hopper comprises a tailing
outlet.
2. The system of claim 1, wherein the vessel further comprises at
least one perforated baffle.
3. The system of claim 1, wherein at least one hopper is of a
different size or shape than another hopper.
4. The system of claim 1, wherein the vessel further comprises a
solvent injection inlet.
5. The system of claim 1, further comprising a second separator
operatively coupled to the feed outlet or a tailing outlet of a
hopper.
6. The system of claim 5, wherein the secondary separator is
operatively coupled to the tailing outlet of a hopper, wherein the
secondary separator comprises a plurality of secondary separator
vessels, and wherein each secondary separator vessel comprises at
least one secondary hopper.
7. A method for recovering hydrocarbons in an oil sands solvent
extraction process, comprising: passing a bituminous feed through
an inlet of a vessel; passing the bituminous feed across a
plurality of hoppers disposed on a lower end of the vessel;
separating the bituminous feed into a stream comprising bitumen and
a stream comprising tailings; passing the stream comprising bitumen
from the vessel; and passing the stream comprising tailings from
the vessel.
8. The method of claim 7, further comprising adjusting the flow
rate of the bituminous feed flow based at least in part on the
residence time required to obtain a predetermined separation.
9. The method of claim 7, further comprising passing the stream
comprising tailings to a secondary separator structure, wherein the
secondary separator structure comprises a second vessel having a
second plurality of hoppers.
10. The method of claim 9, further comprising injecting a solvent
into the secondary separator structure, the vessel, or both.
11. The method of claim 9, wherein the secondary separator
structure comprises a plurality of second vessels each comprising
at least one hopper.
12. The method of claim 9, further comprising: passing the stream
comprising tailings to a plurality of wash stages in a
counter-current configuration.
13. The method according to claim 12, further comprising: adding
neat solvent to a final wash stage; generating a stream comprising
solvent diluted bitumen; and generating a second stream comprising
tailings.
14. The method according to claim 13, wherein the stream comprising
solvent diluted bitumen is used as the wash fluid for preceding
wash stages.
15. The method of claim 7, further comprising passing at least a
portion of the additional bitumen to the inlet of first vessel.
16. The method of claim 7, wherein passing the stream comprising
tailings from the vessel through an outlet of the vessel occur via
a unitary outlet.
17. The method of claim 7, wherein the bituminous feed comprises a
solvent-extracted bitumen, further comprising: passing the stream
comprising bitumen to a solvent recovery unit; and separating the
stream comprising bitumen into a stream comprising a
solvent-extracted bitumen and a stream comprising solvent.
18. The method according to claim 7, further comprising:
precipitating a portion of the asphaltenes from the bituminous
feed; separating the stream comprising solvent, bitumen,
asphaltenes, and tailings into: a solvent containing bitumen stream
and a tailings stream containing asphaltenes
19. The method of claim 18, wherein the bituminous feed comprises a
bituminous froth.
20. The method of claim 7, wherein separating the bituminous feed
occurs substantially in a mine, further comprising transporting at
least a portion of the stream comprising bitumen to a
geographically remote location.
21. A system for separating a bituminous feed in an oil sands
solvent extraction process, comprising: a vessel; an inlet device
coupled to a vessel and configured to receive the bituminous feed;
an outlet device coupled the vessel and configured to discharge a
tailings feed; a plurality of bitumen outlets disposed on the
vessel; a plurality of hoppers disposed on a lower end of the
vessel, wherein each hopper comprises a tailing outlet; and a
secondary extraction vessel operatively coupled to the outlet
device so as to pass bitumen extracted in the secondary extraction
vessel to the inlet device in a counter-current extraction.
22. The system of claim 21, further comprising a secondary
separator structure, wherein the secondary separator structure
comprises a plurality of vessels having a second plurality of
hoppers, wherein the secondary separator structure comprises an
injection inlet for injecting water or a solvent, and wherein the
injection inlet is coupled to an injection header extending to at
least two of the plurality of vessels.
23. The system of claim 22, further comprising a solvent recovery
unit operatively coupled to at least one bitumen outlet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the priority benefit of U.S. patent
application Ser. No. 62/067,279 filed Oct. 22, 2014 entitled
HORIZONTAL-FLOW OIL SANDS SEPARATOR FOR A SOLVENT EXTRACTION
PROCESS, the entirety of which is incorporated by reference
herein.
BACKGROUND
[0002] This section is intended to introduce various aspects of the
art, which may be associated with the present disclosure. This
discussion is believed to assist in providing a framework to
facilitate a better understanding of particular aspects of the
present disclosure. Accordingly, it should be understood that this
section should be read in this light, and not necessarily as
admissions of prior art.
[0003] Oil sands are sand deposits which in addition to sand
comprise clays, connate-water and bitumen. Depending on the depth
of the deposit, bitumen may be recovered by mining or in situ
thermal methods. Oil sand ore in a mining and extraction operation
is typically processed using mechanical means and chemicals
addition to separate the bitumen from the sands. Recovering the
highly viscous bitumen from the oil sand poses numerous challenges,
particularly since large quantities of heat and water are required
to extract the bitumen. Further, most oil sand deposits are located
in remote areas (such as, for example, in northeastern Alberta,
Canada), which can contribute to increased costs for transportation
and processing, especially in harsh weather conditions. Because of
these challenges, obtaining a good yield of bitumen product from
the oil sands is desired in order to reduce costs and waste.
[0004] In conventional gravity separators, a slurry stream
comprising liquid and solid particles is delivered to a vessel
where the solid particles settle by gravity and are removed from
the bottom of the vessel, while the clarified liquid is removed
from the top of the vessel. In most processes, the solid particles
are distributed in size, where the large particles settle more
quickly and the small particles settle more slowly. Particles that
have settling velocities smaller than the upward flux (superficial
velocity) of the liquid may not settle at all, but may instead be
carried over with the clarified liquid. Conventional separators
generally achieve their optimum separation efficiency by having a
uniform upward velocity distribution as this determines the
theoretical limit of the maximum particle size that can be carried
over. Increasing the vessel size, for example, decreases the upward
velocity and thereby reduces the size of the largest particles that
carry-over, thereby increasing the fraction of particles that
report to the underflow.
[0005] The water-based extraction process (WBE) is a commonly used
process to extract bitumen from mined oil sands. In another
technique, a non-water-based extraction process can be used to
treat the strip or surface mined oil sands. The non-water-based
extraction process may interchangeably be referred to as a solvent
based extraction process or an oil sands solvent extraction
process. The commercial application of a solvent based extraction
process has, for various reasons, eluded the oil sands industry. A
major challenge associated with the solvent based extraction
process is the tendency of fine particles within the oil sands to
hamper the separation of solids from the heavy oil extracted. The
heavy oil extracted may interchangeably be referred to as bitumen
extract. Fine particles may interchangeably be referred to as a
fine solids stream or fines.
[0006] One proposed way to handle the challenge of fine particles
is described in Canadian Patent No. 1,169,002 (Karnofsky).
Karnofsky describes a process wherein an oil sands slurry is
separated into a coarse solids stream and a fine solids stream by
gravity separation. Bitumen extract is removed from the coarse
solids stream by using a series of percolating beds. Bitumen
extract is removed from the fines solids stream by using a
complicated system of clarifiers, thickeners, and filters. Despite
the process described in Karnofsky, solid-liquid separation of the
fines solids stream remains a challenge.
[0007] Another proposed way to handle the challenge of fine
particles is by using a solid agglomeration process. The solid
agglomeration process was coined Solvent Extraction Spherical
Agglomeration (SESA). A description of the SESA process can be
found in Sparks et al., Fuel 1992(71); pp 1349-1353. Previously
described methodologies for SESA have not been commercially
adopted. In general, the SESA process involves mixing oil sands
with a hydrocarbon solvent to form an oil sands slurry, adding an
aqueous bridging liquid to the oil sands slurry to form a mixture,
agitating the mixture in a slow and controlled manner to nucleate
particles, and continuing such agitation so as to permit these
nucleated particles to form larger multi-particle spherical
agglomerates for removal. The aqueous bridging liquid may be water
or an aqueous solution since the solids of oil sands are mostly
hydrophilic and water is immiscible to hydrocarbon solvents. The
aqueous bridging liquid preferentially wets the solids. With the
right amount of the aqueous bridging liquid and suitable agitation
of the slurry, the aqueous bridging liquid displaces the suspension
liquid on the surface of the solids. As a result of interfacial
forces among three phases (i.e. the aqueous bridging liquid, the
suspension liquid, and the solids), fine particles within the
solids consolidate into larger, compact agglomerates that are more
readily separated from the suspension liquid.
[0008] U.S. Pat. No. 4,719,008 (Sparks) describes a process that
applies SESA using a micro-agglomerate procedure. In Sparks, the
SESA process occurs within a slowly rotating horizontal vessel. The
conditions of the slowly rotating horizontal vessel are that which
favor the formation of large agglomerates; however, a light milling
action is used to continuously break down the agglomerates. The
micro-agglomerates are formed by obtaining an eventual equilibrium
between cohesive and destructive forces. Since rapid agglomeration
and agglomerates of large size can lead to bitumen recovery losses
owing to entrapment of bitumen extract within the agglomerated
solids, the level of bridging liquid is kept to as low as possible
commensurate with achieving economically viable solid-liquid
separations.
[0009] With the formation of micro-agglomerates, the process of
solid-liquid separation using common separation devices is easier
compared to a situation where fine particles are not
micro-agglomerated. Applicable separation devices include at least
one of gravity separators, centrifuges, cyclonic separation
devices, screens and filters. Although the separation devices have
been shown to be effective in separating agglomerates from liquids,
they have disadvantages that may limit their application in an oil
sands solvent extraction process. For example, gravity separators,
such as clarifiers and incline plate separators, can result in a
bitumen extract of low solids content; the underflow from the
gravity separators is expected to have a substantial amount of
bitumen extract entrained within the underflow. Because of this
bitumen entrainment in the underflow, a significant amount of wash
solvent and many wash stages is needed to separate the substantial
amount of bitumen extract--interchangeably referred to as residual
bitumen--from the solids. Cyclonic separation devices, such as
hydrocyclones, are compact and allow for rapid separation of solids
from liquids. However, it is difficult to use cyclonic separation
devices to clarify the bitumen extract and concentrate the solids
stream to, say, greater than 50 wt. % solids. In solid-liquid
separation processes, paste thickeners, centrifuges or filters are
known to produce solid slurries of greater than 50 wt. %. The paste
thickeners, centrifuges or filters have moving parts that may
challenge their reliability in the high solids content and
hydrocarbon environment of the solvent extraction process.
[0010] Consequently, a need exists for an efficient oil sands
separator in an oil sands solvent extraction process that reduces
the space requirements at the site. Further, a need exists for an
efficient oil sands separator for an oil sands solvent extraction
process that reduces the difficulties and/or expenses associated
with manufacture and/or transportation to remote sites.
[0011] Bitumen product cleaning generally refers to another stage
within the oil sands process wherein solid separation is required.
In a bitumen product cleaning process, bitumen extracted from the
ore yet still containing varying amounts of water and solids is
subjected to a deasphalting process, which forms asphaltene-rich
aggregates that can be removed with residual solids and water via
gravity settling. Conventional gravity settling may generally refer
to techniques for separating a feed containing immiscible phases of
different densities, e.g., settling of a feed in a vessel to obtain
a heavier phase zone in the vicinity of the base and a lighter
phase zone above an interface with the heavier phase zone. U.S.
patent publication number 2012/014,653, titled "Apparatus and
Method for Separating a Feed Material Containing Immiscible Phases
of Different Densities," contains a representative gravity settling
approach.
SUMMARY
[0012] One embodiment includes a system for recovering hydrocarbons
from a bituminous feed in an oil sands solvent extraction process,
comprising a vessel comprising a feed inlet on a proximate end of
the vessel, a feed outlet on a distal end of the vessel, a bitumen
outlet, and a plurality of hoppers, wherein each hopper comprises a
tailing outlet.
[0013] Another embodiment includes a method for recovering
hydrocarbons in an oil sands solvent extraction process, comprising
passing a bituminous feed through an inlet of a vessel, passing the
bituminous feed across a plurality of hoppers disposed on a lower
end of the vessel, separating the bituminous feed into a stream
comprising bitumen and a stream comprising tailings, passing the
stream comprising bitumen from the vessel, and passing the stream
comprising tailings from the vessel.
[0014] Still another embodiment includes a system for separating a
bituminous feed in an oil sands solvent extraction process,
comprising a vessel, an inlet device coupled to a vessel and
configured to receive the bituminous feed, an outlet device coupled
the vessel and configured to discharge a tailings feed, a plurality
of bitumen outlets disposed on the vessel, a plurality of hoppers
disposed on a lower end of the vessel, wherein each hopper
comprises a tailing outlet, and a secondary extraction vessel
operatively coupled to the outlet device so as to pass bitumen
extracted in the secondary extraction vessel to the inlet device in
a counter-current extraction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The advantages of the present techniques are better
understood by referring to the following detailed description and
the attached drawings, in which:
[0016] FIG. 1 is a schematic diagram of a separator system for
separating a bituminous feed in an oil sands solvent extraction
process.
[0017] FIG. 2 is a cross section of a horizontal-flow separator
system for recovering hydrocarbons from a bituminous feed in an oil
sands solvent extraction process.
[0018] FIG. 3A is an inlet side view cross sectional diagram of a
system for recovering hydrocarbons from a bituminous feed in an oil
sands solvent extraction process.
[0019] FIG. 3B is a perspective view of the system for recovering
hydrocarbons from a bituminous feed in an oil sands solvent
extraction process.
[0020] FIG. 4 is a block diagram describing a process for
recovering hydrocarbons from a bituminous feed in an oil sands
solvent extraction process.
[0021] FIG. 5 is a block diagram describing a continued process for
recovering hydrocarbons from a bituminous feed in an oil sands
solvent extraction process.
[0022] FIG. 6 is an embodiment of system for recovering
hydrocarbons from a bituminous feed in an oil sands solvent
extraction process.
DETAILED DESCRIPTION
[0023] In the following detailed description section, specific
embodiments of the present techniques are described. However, to
the extent that the following description is specific to a
particular embodiment or a particular use of the present
techniques, this is intended to be for exemplary purposes only and
simply provides a description of the exemplary embodiments.
Accordingly, the techniques are not limited to the specific
embodiments described herein, but rather, include all alternatives,
modifications, and equivalents falling within the true spirit and
scope of the appended claims.
[0024] Disclosed herein is a horizontal-flow separator for
separating bitumen/water/solids stream(s) in oil sands operations.
Many configurations are possible, some including small diameter
fingers to accomplish polishing of the solvent/bitumen prior to
further processing and commercialization. For example, the primary
separator vessel may be the first stage separator in a process,
with the smaller fingers serving as the second stage separator.
Alternately, both stages could simultaneously accomplish one step
of separation in the overall process. Some embodiments place feeds
or draws between these two parts of a separation system. Conical
section(s) in the first and/or second stage separators may have
different base angles and/or sizes depending on the various
physical properties and/or characteristics of the liquids and
solids being processed.
[0025] Horizontal-flow separators may be inherently better at
remove smaller particles often found in oil sands tailings.
Additionally, horizontal-flow separators may allow designers an
additional degree of freedom in sizing the separator(s). Owing to
Stokes' Law, vertical-flow separators depend on the upflow velocity
to determine the theoretical particle cut-size obtainable with the
separator. Both diameter (superficial fluid velocity) and length
(residence time) can be adjusted for horizontal-flow separators to
meet product stream specifications based upon Stokes' Law settling.
However, disclosed horizontal-flow designs allow designers
additional degrees-of-freedom in configuring the separator(s). As
the disclosed separators include generally smaller diameter vessels
(or even pipe size fingers), it is likely to facilitate manufacture
and transport to remote sites, resulting in capital savings over
the current separator technology. Labor costs to erect the
separator should also be reduced in view of the above.
[0026] At the outset, for ease of reference, certain terms used in
this application and their meanings as used in this context are set
forth. To the extent a term used herein is not defined herein, it
should be given the broadest definition persons in the pertinent
art have given that term as reflected in at least one printed
publication or issued patent. Further, the present techniques are
not limited by the usage of the terms shown herein, as all
equivalents, synonyms, new developments, and terms or techniques
that serve the same or a similar purpose are considered to be
within the scope of the present claims.
[0027] As used herein, the term "Bitumen" is a naturally occurring
heavy oil material. Generally, it is the hydrocarbon component
found in oil sands. Bitumen can vary in composition depending upon
the degree of loss of more volatile components. It can vary from a
very viscous, tar-like, semi-solid material to solid forms. The
hydrocarbon types found in bitumen can include aliphatics,
aromatics, resins, and asphaltenes. A typical bitumen might be
composed of:
[0028] 19 weight (wt.) % aliphatics (which can range from 5 wt.
%-30 wt. %, or higher);
[0029] 19 wt. % asphaltenes (which can range from 5 wt. %-30 wt. %,
or higher);
[0030] 30 wt. % aromatics (which can range from 15 wt. %-50 wt. %,
or higher);
[0031] 32 wt. % resins (which can range from 15 wt. %-50 wt. %, or
higher); and
[0032] some amount of sulfur (which can range in excess of 7 wt.
%).
In addition, bitumen can contain some water and nitrogen compounds
ranging from less than 0.4 wt. % to in excess of 0.7 wt. %. The
percentage of the hydrocarbon found in bitumen can vary. The term
"heavy oil" includes bitumen as well as lighter materials that may
be found in a sand or carbonate reservoir.
[0033] As used herein, the term "bituminous feed" refers to a
stream derived from oil sands that requires downstream processing
in order to realize valuable bitumen products or fractions. The
bituminous feed is one that comprises bitumen along with
undesirable components. Such a bituminous feed may be derived
directly from oil sands, and may be, for example, raw oil sands
ore. Further, the bituminous feed may be a feed that has already
realized some initial processing, e.g., non-aqueous extraction
(NAE) processing, solvent extraction processing, etc., but
nevertheless requires further processing. Also, recycled streams
that comprise bitumen in combination with other components for
removal as described herein can be included in the bituminous feed.
A bituminous feed need not be derived directly from oil sands, but
may arise from other processes. For example, a waste product from
other processes which comprises bitumen that would otherwise not
have been recovered, may be used as a bituminous feed. Such a
bituminous feed may be also derived directly from oil shale oil,
bearing diatomite or oil saturated sandstones.
[0034] As used herein, the phrase "fine particles" means those
solids having a size of less than 44 microns (.mu.m), that is,
material that passes through a 325 mesh (44 micron). The
aforementioned range includes any number within the range.
[0035] As used herein, the phrase "coarse particles" means those
solids having a size of greater than 44 microns (.mu.m). The
aforementioned range includes any number within the range.
[0036] As used herein, the phrase "Heavy oil" includes oils which
are classified by the American Petroleum Institute ("API"), as
heavy oils, extra heavy oils, or bitumens. The term "heavy oil"
includes bitumen. Heavy oil may have a viscosity of about 1,000
centipoise (cP) or more, 10,000 cP or more, 100,000 cP or more, or
1,000,000 cP or more. In general, a heavy oil has an API gravity
between 22.3.degree. API (density of 920 kilograms per meter cubed
(kg/m.sup.3) or 0.920 grams per centimeter cubed (g/cm.sup.3)) and
10.0.degree. API (density of 1,000 kg/m.sup.3 or 1 g/cm.sup.3). An
extra heavy oil, in general, has an API gravity of less than
10.0.degree. API (density greater than 1,000 kg/m.sup.3 or 1
g/cm.sup.3). For example, a source of heavy oil includes oil sand
or bituminous sand, which is a combination of clay, sand, water and
bitumen. The recovery of heavy oils is based on the viscosity
decrease of fluids with increasing temperature or solvent
concentration. Once the viscosity is reduced, the mobilization of
fluid by steam, hot water flooding, or gravity is possible. The
reduced viscosity makes the drainage quicker and therefore directly
contributes to the recovery rate.
[0037] As used herein, the terms "bitumen", "bitumens", and
"bituminous feed" are used interchangeably.
[0038] As used herein, the term "solvent" can refer to either a
single chemical component, or a mixture of chemical components, to
promote the dissolution of other chemical compounds.
[0039] As used herein, the terms "solvent extracted bitumen" and
"solvent diluted bitumen" refer to bitumen that is dissolved into
another hydrocarbon. This other hydrocarbon could refer to a
solvent used to extract the bitumen to facilitate removal from the
other ore components or alternatively could refer to a solvent that
dissolves only a portion of the bitumen molecules.
[0040] As used herein, the term "hopper" means a container with a
narrow opening at bottom. This definition is intended to encompass
frustum-shaped hoppers, e.g., pyramidal frustum, conical frustum,
square frustum, pentagonal frustum, etc., as well as various
prismatoids and other slant geometries that may be suitably be
employed by those of skill in the art to practice the techniques
described herein.
[0041] As used herein, the term "hydrocarbon" means an organic
compound that primarily includes the elements of hydrogen and
carbon, although nitrogen, sulfur, oxygen, metals, or any number of
other elements may be present in small amounts. Hydrocarbons
generally refer to components found in heavy oil or in oil sands.
However, the techniques described are not limited to heavy oils but
may also be used with any number of other reservoirs to improve
gravity drainage of liquids. Hydrocarbon compounds may be aliphatic
or aromatic, and may be straight chained, branched, or partially or
fully cyclic.
[0042] As used herein, the term "macro-agglomeration" means the
consolidation of both fine particles and coarse particles that make
up the oil sands. Macro-agglomerates may have a mean diameter of 2
millimeters (mm) or greater.
[0043] As used herein, the term "micro-agglomeration" means the
consolidation of fine particles that make up the oil sands.
Micro-agglomerates may have a mean diameter of less than 2
millimeters (mm).
[0044] As used herein, the term "tailings" means an underflow
material remaining in a mixture after bitumen is separated from an
oil sands or a bituminous feed. Tailings generally comprise the
refuse material comprising fine and/or coarse particles of sand
and/or clay, traces of bitumen, asphaltenes, etc. remaining after
the bitumen has been extracted from the bituminous feed.
[0045] As used herein, the phrase "product cleaning" refers to a
process wherein bitumen is subjected to a process to reduce
impurities (including, but not limited to, water and solids) to
levels that allow for direct marketing to refineries or to match
feed requirements for other conversion technologies focused on
generating a synthetic crude oil or to meet pipeline product
specifications.
[0046] As used herein, the phrases "solvent-based recovery process"
or "solvent extraction process" include any type of hydrocarbon
recovery process that uses a solvent, at least in part, to enhance
the recovery, for example, by diluting or lowering a viscosity of
the hydrocarbon. Solvent-based recovery processes may be used in
combination with other recovery processes, such as, for example,
thermal recovery processes. As used herein, the terms "a" and "an,"
mean one or more when applied to any feature in embodiments of the
present inventions described in the specification and claims. The
use of "a" and "an" does not limit the meaning to a single feature
unless such a limit is specifically stated.
[0047] As used herein, the term "about" means .+-.10% of the
subsequent number, unless otherwise stated.
[0048] As used herein, the terms "approximate," "approximately,"
"substantial," and "substantially," mean a relative amount of a
material or characteristic that is sufficient to provide the
intended effect. The exact degree of deviation allowable in some
cases may depend on the specific context. It should be understood
by those of skill in the art who review this disclosure that these
terms are intended to allow a description of certain features
described and claimed without restricting the scope of these
features to the precise numeral ranges provided. Accordingly, these
terms should be interpreted as indicating that insubstantial or
inconsequential modifications or alterations of the subject matter
described and are considered to be within the scope of the
disclosure.
[0049] As used herein, the definite article "the" preceding
singular or plural nouns or noun phrases denotes a particular
specified feature or particular specified features and may have a
singular or plural connotation depending upon the context in which
it is used.
[0050] FIG. 1 is a schematic diagram of a conventional separator
system 100 for separating a bituminous feed in an oil sands solvent
extraction process. The separator system 100 includes a deep cone
settler 102 is depicted for receiving agglomerated slurry 104 from
an agglomerator (not depicted). The deep cone settler 102 permits
settling of agglomerated solids to the lower region 106, while a
low solids bitumen extract 108 can be drawn off as overflow. A pump
110 is used to convey the overflow to further cleaning or solvent
removal in a solvent recovery unit. A vent gas 112a and 112b is
provided to and removed from the deep cone settler 102 to provide a
low oxygen environment within the deep cone settler 102. One or
more pumps 114 may be used to pump agglomerates 116 to a
counter-current washer 118, e.g., a belt filter or a rotary pan
filter, for effecting recovery of residual bitumen from
agglomerates.
[0051] FIG. 2 is a cross section of a horizontal-flow separator
system 200 for recovering hydrocarbons from a bituminous feed in an
oil sands solvent extraction process. The system 200 includes a
vessel 202 having a feed inlet 204 on a proximate end 206 of the
vessel 202 and a feed outlet 208 on a distal end 210 of the vessel
202. The vessel 202 also has a plurality of bitumen outlets 212 on
an upper end 214 of the vessel 202 and hoppers 216 having solvent
and/or tailing outlets 218 on a lower end 221 of the vessel 202.
The vessel 202 optionally houses a plurality of internal flow path
obstructions or baffles 220, e.g., perforated baffles, disposed
across the internal surface of the vessel 202. The bitumen outlets
212 optionally comprise outlet baffles 222, e.g., perforated
baffles. While shown at approximately the midline of the top of the
vessel 202, those of skill in the art will recognize that the
bitumen outlets 212 may alternately or additionally be located
elsewhere on the upper end 214 of the vessel 202, e.g., on or
towards the distal end 210, within the scope of this disclosure.
Similarly, while shown at approximately the centerline of the
vessel 202, those of skill in the art will appreciate that a
plurality of suitable locations exist for placement of the feed
inlet 204 and the feed outlet 208, e.g., on the upper end 214, the
lower end 221, or a side, upper, or lower wall of the vessel 202 at
the proximate end 206 or distal end 210 of the vessel 202. Such
alternate placement may be based on a variety of considerations,
e.g., obtaining a desired flowpath into and/or out of the vessel
202, structural limitations external to the vessel 202, etc. The
vessel 202 may optionally include one or more injection inlets (not
depicted) for injecting water and/or solvent.
[0052] In operation, a bituminous feed may enter the vessel 202
through the feed inlet 204. The feed may flow horizontally across
the vessel 202 and the hoppers 216 to the feed outlet 208. As feed
flows across the hoppers 216, the angle of the wall(s) of each
hopper 216 and the upflow (rise) created by feed incidence against
the wall(s) of each hopper 216 may cause separation according to
known particle settling principles, e.g., Stokes' Law settling.
This process causes bitumen to float to the top of the vessel 202
where it may be collected via bitumen outlets 212. In some
embodiments, the size, shape, and/or narrowing angle of the hopper
(or incidence wall angle) of the hoppers 216 are varied from one
hopper 216 to another, e.g., to obtain bulk and fine settling, to
alter the rate of rise and/or settling, etc. In some embodiments,
separation may alternatively or be additionally accomplished
through horizontal flow settling as in traditional three-phase
separators. Thus, hoppers 216 may function to collect high solid
component streams for ease of continuous removal (e.g., separation
may not necessarily be created by upflow caused by impedance
against hopper walls).
[0053] The velocity of the bituminous feed flow may be altered by a
variety of techniques known in the art, e.g., via pressurization,
preliminary feed treatment, additional pumps, etc., in order to
obtain certain desired separation characteristics within the vessel
202. Alternately or additionally, as described above, baffles 220
and/or 222 may be optionally added at various points to impede or
direct flow. Additionally, some embodiments may inject water and/or
solvent into the feed stream via an injection inlet disposed on the
vessel 202 in order to alter one or more characteristics of the
feed, e.g., viscosity, separation, disaggregation, etc. As the feed
separates, water and/or tailings, may pass through the solvent
and/or tailing outlets 218 as bitumen is collected through the
bitumen outlets 212. A feed stream comprising substantially
unseparated bituminous feed may continue through the feed outlet
208. In some embodiments, at least a portion of the discharge
through the feed outlet 208 is recycled through the vessel 202. In
some embodiments, at least a portion of the discharge through the
feed outlet 208 is passed to a second vessel 202 to substantially
repeat the process.
[0054] FIG. 3A is an inlet side view cross sectional diagram of a
system 300 for recovering hydrocarbons from a bituminous feed in a
solvent extraction process. FIG. 3B is a perspective view of the
system 300 for recovering hydrocarbons from a bituminous feed in a
solvent extraction process. The components of the system 300 may be
substantially the same as the corresponding components of FIG. 2
unless otherwise noted. The system 300 comprises a secondary
separator 302 commonly coupled to the tailing outlets 218. Some
embodiments may attach a secondary separator 302 to less than all
of the tailing outlets 218, and other embodiments may attach
separate secondary separators 302 to one or more of the tailing
outlets 218. The secondary separator 302 has a water and/or solvent
injection inlet 303 for injecting water and/or solvent. Those of
skill in the art will appreciate that in some embodiments the
solvent injection inlet 303 may optionally comprise a common
injection header spanning the length of a common secondary
separator 302 or a plurality of secondary separators 302 (in
suitable embodiments) for distributing the water and/or solvent.
The secondary separator 302 has a plurality of secondary vessels
304, also referred to herein as "fingers" 304, having a plurality
of secondary hoppers 306 with secondary water and/or tailings
outlets 308. While depicted with a plurality of secondary hoppers
306, alternate embodiments may have more, fewer, or even no
secondary hoppers 306. Further, different fingers 304 may have
differing numbers of secondary hoppers 306, and may include
differing sizes, shapes, and/or narrowing angles of any of the
secondary hoppers 306. The fingers 304 each have a hydrocarbon or
bitumen outlet 310 for passing hydrocarbons therethrough. Although
not depicted, those of skill in the art will appreciate that a
plurality of baffles may be optionally added in the secondary
separator 302 as described above with respect to the baffles 220
and/or 222 in the vessel 202.
[0055] In operation, the vessel 202 portion of the system 300 may
function as described above in connection with the system 200.
Namely, a bituminous feed may enter the vessel 202 through the feed
inlet 204. The feed may flow horizontally across the vessel 202 and
the hoppers 216 to the feed outlet 208. As feed flows across the
hoppers 216, the angle of the wall(s) of each hopper 216 and the
upflow (rise) created by feed incidence against the wall(s) of each
hopper 216 causes separation according to known particle settling
principles. This process causes bitumen to float to the top of the
vessel 202 where hydrocarbons may be collected via bitumen outlets
212. As the feed separates, a stream comprising substantially
unseparated bituminous feed may continue through the feed outlet
208 as bitumen is collected through the bitumen outlets 212.
Solvent, tailings, and/or some amount of bituminous feed
(collectively, the "secondary bituminous feed") may pass through
the solvent and/or tailing outlets 218 and into the secondary
separator 302. Solvent may be injected into the secondary separator
302 at the solvent injection inlet 303 in order to alter one or
more characteristics of the secondary bituminous feed, e.g.,
viscosity, separation, disaggregation, etc. It will be noted that a
variety of locations are available for placing the injection inlet
303, including at each water and/or tailings outlet 218, and such
alternate embodiments are within the scope of this disclosure. The
secondary bituminous feed may be passed through the fingers 304 for
secondary or second phase separation. Second phase separation in
each of the fingers 304 may occur in substantially the same the
same way as the initial or first phase separation in the vessel
202. Specifically, as the secondary bituminous feed flows across
the secondary hoppers 306, the angle of the wall(s) of each hopper
306 and the upflow (rise) created by feed incidence against the
wall(s) of each hopper 306 causes separation according to known
particle settling principles. This process causes hydrocarbons or
bitumen to float to the top of the fingers 304 where the
hydrocarbons or bitumen may be collected via bitumen outlets 310.
The remainder of the secondary bituminous feed, which may comprise
substantially tailings, may be discharged through the secondary
water and/or tailings outlets 308. Following discharge, the
remaining secondary bituminous feed may be recirculated and/or
otherwise combined with the bituminous feed, may be sent for
further processing, may be collected and disposed of as tailings,
or may undergo another process as optionally determined according
to the skill of those in the art.
[0056] FIG. 4 is a block diagram describing a process 400 for
recovering hydrocarbons in a solvent extraction process. At block
402, the process 400 may pass a bituminous feed through an inlet,
e.g., the feed inlet 204 of FIG. 2, of a vessel, e.g., the vessel
202 of FIG. 2. At block 404, the process 400 may flow the solvent
extracted bitumen across a plurality of hoppers, e.g., the hoppers
216 of FIG. 2, disposed on a lower end of the vessel. At block 406,
the process 400 may separate the solvent extracted bitumen to
obtain bitumen and tailings. Separating the solvent extracted
bitumen may include flowing the solvent extracted bitumen across
the hoppers. In so doing, the angle of the wall(s) of each hopper
and the upflow (rise) created by feed incidence against the wall(s)
of each hopper may cause separation according to known particle
settling principles, e.g., Stokes' Law settling. At block 408, the
process 400 may remove the hydrocarbons and/or solvent extracted
bitumen from the vessel, e.g., via bitumen outlets 212. At block
410, the process 400 may remove at least a portion of the tailings
created from the separation process from the vessel. For example,
the tailings may be discharged through one or more solvent and/or
tailing outlets, e.g., the solvent and/or tailing outlets 218 of
FIG. 2. At block 412, the process 400 may pass at least a portion
of the solvent extracted bitumen through an outlet, e.g., the feed
outlet 208 of FIG. 2, of the vessel.
[0057] FIG. 5 is a block diagram describing a continued process 500
for recovering hydrocarbons in a solvent extraction process. The
process 500 may comprise the process 400 and may begin after block
412 of FIG. 4. At block 502, the at least a portion of the solvent
extracted bitumen, or secondary solvent extracted bitumen stream,
is passed to a secondary separator, e.g., the secondary separator
302 of FIG. 3. At block 504, the secondary solvent extracted
bitumen stream is fed to at least one secondary vessel finger,
e.g., a finger 304 of FIG. 3. At block 506, each finger may
separate the secondary solvent extracted bitumen stream. For
example, each finger may comprise at least one hopper, e.g., a
secondary hopper 306 of FIG. 3, and may flow the secondary solvent
extracted bitumen across the hopper to obtain a desired settling of
the secondary solvent extracted bitumen. At block 508, hydrocarbons
or bitumen may be collected through one or more finger outlets,
e.g., a bitumen outlet 310, and the remainder of the secondary
solvent extracted bitumen, which may comprise substantially
tailings, may be discharged through one or more outlets, e.g.,
solvent and/or tailings outlets 308 of FIG. 3.
[0058] FIG. 6 is an embodiment of a system 600 for recovering
hydrocarbons from a bituminous feed in a solvent extraction
process. The components of the system 600 may be substantially the
same as the components of the system 300 of FIG. 3 except as
otherwise noted. The bituminous feed input 602 into the system 600
is configured to receive a bituminous feed comprising substantially
solvent-extracted bitumen having agglomerated solids. The system
600 includes two separator systems 604a and 604b, e.g., each a
system 300 of FIG. 3, modified as noted herein, arranged in a
counter-current configuration. It will be appreciated that the
systems 604a and 604b each comprise a unitary outlet for tailings,
e.g., lines 606a and 606b, respectively. The output stream of
tailings passed via line 606a is passed to the system 604b, e.g.,
serving as the bituminous feed input into the system 604b, while
the output stream of tailings from the system 604b passed via line
606b is passed to a solids desolventizer 608 in order to thereby
pass a stream comprising dry solids via line 610. The solvent
recovered by the desolventizer 608 may be returned via line 612 to
the stream of tailings in line 606a for further processing via the
system 604b. Bitumen may exit the system 604a and be split into two
lines, 614a and 614b. Line 606a may carry bitumen to a solvent
recovery unit 616. The solvent recovery unit 616 may separate the
received feed into a stream comprising bitumen, passed via line
618, and a stream comprising "neat" or "lean" solvent, passed via
line 620. The stream comprising neat solvent passed via line 620
may join the stream comprising solvent passed via line 612. Line
614b may return at least a portion of the bitumen to the inlet of
the system 604a. To enable the counter-current configuration, rich
solvent may exit the system 604b via line 614c and return to join
the bituminous input feed 602. Although depicted with only two wash
stages, i.e., the configuration of systems 604a and 604b, the
number of wash stages may be optionally extended, e.g., by passing
the tailings stream to a series of wash stages arranged in a
counter-current wash configuration, to meet a specified bitumen
recovery requirement. As will be understood by those of skill in
the art, in a counter-current configuration neat solvent is exposed
to a solvent-diluted bitumen stream while rich solvent is exposed
to a bitumen stream without or comprising comparatively less
solvent than the solvent-diluted bitumen, e.g., the bituminous
feed.
[0059] FIG. 6 provides another embodiment wherein the solvent
extracted bitumen is subjected to a bitumen product cleaning stage.
In this embodiment, solvent extracted bitumen enters at 602 and is
contacted by paraffin-rich stream 614c to promote partial
deasphalting, or precipitating a portion of the asphaltenes from
the bituminous feed. This combined stream enters the system 604a to
generate an overflow stream comprising solvent diluted bitumen 614a
(i.e., comprising both solvent and bitumen) and an underflow stream
containing precipitated asphaltenes, water, and solids passed via
line 606a. This underflow stream is contacted by recycled
paraffin-rich solvent, recycled via solvent recovery process
desolventizer 608 and 616, and sent to another system 604b. The
underflow from the system 604b is subjected to solvent recovery
process desolventizer 608 to generate a tailings stream 610
containing asphaltenes. The overflow stream 614a from the initial
system 604a is subjected to solvent recovery 616, generating a
solvent recycle stream 620 and a bitumen product stream 618.
[0060] While the present techniques may be susceptible to various
modifications and alternative forms, the exemplary embodiments
discussed herein have been shown only by way of example. However,
it should again be understood that the techniques disclosed herein
are not intended to be limited to the particular embodiments
disclosed. Indeed, the present techniques include all alternatives,
modifications, combinations, permutations, and equivalents falling
within the scope of the disclosure and appended claims.
* * * * *