WO2016064495A1

WO2016064495A1 - Horizontal-flow oil sands separator for an aqueous extraction process

Info

Publication number: WO2016064495A1
Application number: PCT/US2015/050571
Authority: WO
Inventors: Andrew P. STEINHAUSER; Edward J. Grave; Paul D. Oldenburg
Original assignee: Exxonmobil Upstream Research Company
Priority date: 2014-10-22
Filing date: 2015-09-17
Publication date: 2016-04-28
Also published as: CA2959426A1; US20160115390A1

Abstract

The disclosure includes techniques for recovering hydrocarbons from a bituminous feed in an 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.

Description

HORIZONTAL-FLOW OIL SANDS SEPARATOR FOR AN AQUEOUS EXTRACTION PROCESS

CROSS REFERENCE TO RELATED APPLICATIONS

[ΘΘΘ1 ] This application claims the priority benefit of United States Provisional Patent Application No. 62/067,280 filed October 22, 2014 entitled HORIZONTAL-FLOW OIL SANDS SEPARATOR FOR AN AQUEOUS EXTRACTION PROCESS, the entirety of which is incorporated 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 passed or removed from the bottom of the vessel, while the clarified liquid is passed or 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] To achieve the separation described above in an aqueous extraction process, conventional practice is to utilize a comparatively large diameter, vertical-flow separator with multiple inlet nozzles and a conical bottom to separate the solvated bitumen/water/solid stream. Depending on the particular aqueous extraction process, there may be one or multiple separators used in parallel and/or series. The separators may use flow conditioning devices in the inlets or within the body of the separator itself. Owing to their comparatively large size and the remoteness of typical oil sands sites, these separators are often difficult/expensive to manufacture and transport to site.

0006] Consequently, a need exists for an efficient oil sands separator in an aqueous extraction process that reduces the space requirements at the site. Further, a need exists for an efficient oil sands separator for an aqueous extraction process that reduces the difficulties and/or expenses associated with manufacture and/or transportation to remote sites.

[0007] 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. Patent publication number US2012-0145653, titled "Apparatus and Method for Separating a Feed Material Containing Immiscible Phases of Different Densities," contains a representative gravity settling approach.

SUMMARY

10008] One embodiment includes a system for recovering hydrocarbons from a bituminous feed in an 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.

[0009] Another embodiment includes a method for recovering hydrocarbons in an aqueous 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, a stream comprising tailings, and a stream comprising middlings, passing the stream comprising bitumen from the vessel, passing the stream comprising tailings from the vessel, and passing the stream comprising middlings through an outlet of the vessel.

[0010] Still another embodiment includes a system for separating a bituminous feed in an aqueous 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 middlings 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

[00 ] The advantages of the present techniques are better understood by referring to the following detailed description and the attached drawings, in which:

[ΘΘ12] FIG. 1 is a schematic diagram of a separator system for separating a bituminous feed in an aqueous extraction process.

[0013] FIG. 2 is a cross section of a horizontal-flow separator system for recovering hydrocarbons from a bituminous feed in an aqueous extraction process.

[0014] FIG. 3A is an inlet side view cross sectional diagram of a system for recovering hydrocarbons from a bituminous feed in an aqueous extraction process.

[001$] FIG. 3B is a perspective view of the system for recovering hydrocarbons from a bituminous feed in an aqueous extraction process.

[ΘΘ16] FIG. 4 is a block diagram describing a process for recovering hydrocarbons from a bituminous feed in an aqueous extraction process. 10017] FIG. 5 is a block diagram describing a continued process for recovering hydrocarbons from a bituminous feed in an aqueous extraction process.

[0018] FIG. 6A is an embodiment of system for recovering hydrocarbons from a bituminous feed in an aqueous extraction process.

[ΘΘ1 ] FIG. 6B is another embodiment of system for recovering hydrocarbons from a bituminous feed in an aqueous extraction process.

DETAILED DESCRIPTION

[0020] 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.

[0021 ] 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.

10022] 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.

[ΘΘ23] 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.

[ΘΘ24] 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:

19 weight (wt.) % aliphatics (which can range from 5 wt. % - 30 wt. %, or higher);

19 wt. % asphaltenes (which can range from 5 wt. % - 30 wt. %, or higher);

30 wt. % aromatics (which can range from 15 wt. % - 50 wt. %, or higher);

32 wt. % resins (which can range from 15 wt. % - 50 wt. %, or higher); and 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.

[ΘΘ25] As used herein, the term "bituminous feed" refers to a stream derived via an aqueous extraction process 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., aqueous extraction processing, 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 extraction 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.

[0026] As used herein, the term "bituminous froth" refers to a stream comprising substantially more bitumen than middlings or tailings following separation or processing of the bituminous feed. A representative composition of a bituminous froth may include about 60 percent by weight (%/wt) bitumen, about 30%/wt water, and about 10%/wt solids, such as fine or coarse particulate. As will be understood by those of skill in the art, this composition may vary significantly depending on, inter alia, the composition of the bituminous feed. [ΘΘ27] As used herein, the phrase "fine particles" means those solids having a size of less than 44 microns (μιη), that is, material that passes through a 325 mesh (44 micron). The aforementioned range includes any number within the range.

[0028] As used herein, the phrase "coarse particles" means those solids having a size of greater than 44 microns (μιη). The aforementioned range includes any number within the range.

[ΘΘ29] 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° API (density of 920 kilograms per meter cubed (kg/m³) or 0.920 grams per centimeter cubed (g/cm³)) and 10.0° API (density of 1,000 kg/m³ or 1 g/cm³). An extra heavy oil, in general, has an API gravity of less than 10.0° API (density greater than 1,000 kg/m³ or 1 g/cm³). 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.

[0030] 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.

|0031] 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.

|0032] As used herein, the term "middlings" means a stream containing a watery suspension of bitumen and dispersed solids, e.g., fine particles, coarse particles, etc., that remains after a bituminous feed has been separated into a stream of substantially bitumen or bitumen froth and a stream of substantially tailings.

[0033] As used herein, the term "tailings" means an underflow material remaining suspended in a mixture after bitumen and/or middlings are 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, etc. remaining after the bitumen or bitumen froth has been extracted from the bituminous feed.

|0034] 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. In solvent-based recovery processes, a solvent is injected into a subterranean reservoir. The solvent may be heated or unheated prior to injection, may be a vapor or liquid and may be injected with or without steam. Solvent-based recovery processes may include, but are not limited to, solvent assisted cyclic steam stimulation (SA-CSS), solvent assisted steam assisted gravity drainage (SA-SAGD), solvent assisted steam flood (SA-SF), vapor extraction process (VAPEX), heated vapor extraction process (H-VAPEX), cyclic solvent process (CSP), heated cyclic solvent process (H-CSP), solvent flooding, heated solvent flooding, liquid extraction process, heated liquid extraction process, solvent-based extraction recovery process (SEP), thermal solvent-based extraction recovery processes (TSEP), and any other such recovery process employing solvents either alone or in combination with steam. A solvent-based recovery process may be a thermal recovery process if the solvent is heated prior to injection into the subterranean reservoir. The solvent-based recovery process may employ gravity drainage.

[0035] 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.

[ΘΘ36] As used herein, the term "about" means ±10% of the subsequent number, unless otherwise stated.

|0037] 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.

|0038] 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.

[ΘΘ39] FIG. 1 is a schematic diagram of a conventional separator system 100 for separating a bituminous feed. The separator system 100 includes a deep cone settler 102 is depicted for receiving a feed 104. The deep cone settler 102 permits settling of 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 passed or removed from the deep cone settler to provide a low oxygen environment within the deep cone settler 102. One or more pumps 114 may be used to pump the discharge 116 to a countercurrent washer 118 for disposal and/or further processing.

[0040] FIG. 2 is a cross section of a horizontal-flow separator system 200 for recovering hydrocarbons from a bituminous feed in an aqueous 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 water 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.

[0041] In operation, a bituminous feed, e.g., from a hydrotransport pipeline transporting an aqueous oil sands slurry, 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 3-phase separators. 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).

[ΘΘ42] 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, frothing, disaggregation, etc. As the feed separates, water and/or tailings, may pass through the water and/or tailing outlets 218 as bitumen is collected through the bitumen outlets 212. A feed stream comprising substantially middlings and/or 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. Embodiments using the vessel 202 in place of a Primary Separation Cell in a water-based process may generate a middlings stream that is sent to a secondary recovery system comprising a number of stirred vessels in series. The underflow from secondary recovery becomes a tailings (waste) stream. Such embodiments may feed the overflow back into the Primary Separation Cell.

|0043] FIG. 3A is an inlet side view cross sectional diagram of a system 300 for recovering hydrocarbons from a bituminous feed in an aqueous extraction process. FIG. 3B is a perspective view of the system 300 for recovering hydrocarbons from a bituminous feed in an aqueous 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.

[ΘΘ44] 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 middlings and/or unseparated bituminous feed may continue through the feed outlet 208 as bitumen is collected through the bitumen outlets 212. Water, tailings, and/or some amount of bituminous feed (collectively, the "secondary bituminous feed") may pass through the water and/or tailing outlets 218 and into the secondary separator 302. Water and/or solvent may be injected into the secondary separator 302 at the water and/or solvent injection inlet 303 in order to alter one or more characteristics of the secondary bituminous feed, e.g., viscosity, separation, frothing, 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.

[0045] FIG. 4 is a block diagram describing a process 400 for recovering hydrocarbons in an aqueous 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 bituminous feed 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 bituminous feed to obtain bitumen and tailings. Separating the bituminous feed may include flowing the bituminous feed 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 bitumen from the vessel, e.g., via bitumen outlets 212. At block 410, the process 400 may pass or 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 water and/or tailing outlets, e.g., the water and/or tailing outlets 218 of FIG. 2. At block 412, the process 400 may pass at least a portion of the bituminous feed and/or a stream comprising middlings through an outlet, e.g., the feed outlet 208 of FIG. 2, of the vessel.

[ΘΘ46] FIG. 5 is a block diagram describing a continued process 500 for recovering hydrocarbons in an aqueous 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 bituminous feed, or secondary bituminous feed, is passed to a secondary separator, e.g., the secondary separator 302 of FIG. 3. At block 504, the secondary bituminous feed is fed to at least one secondary separator finger, e.g., a finger 304 of FIG. 3. At block 506, each finger may separate the secondary bituminous feed. For example, each finger may comprise at least one hopper, e.g., a secondary hopper 306 of FIG. 3, and may flow the secondary bituminous feed across the hopper to obtain a desired settling of the secondary bituminous feed. 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 bituminous feed, which may comprise substantially tailings, may be discharged through one or more outlets, e.g., water and/or tailings outlets 308 of FIG. 3.

0047] FIG. 6A is an embodiment of an aqueous extraction process 600 for recovering hydrocarbons from a bituminous feed in an aqueous extraction process comprising a system 300. The system 300 may be substantially the same as the system 300 of FIG. 3 unless otherwise noted. In the aqueous extraction process 600, the system 300 replaces a conventional primary separation vessel, e.g., the deep cone settler 102 of FIG. 1. The aqueous extraction process 600 further includes a secondary extraction 602 for performing conventional oil sands separation following initial separation in the system 300. As illustrated, a bituminous feed may be passed to the system 300 via line 604 and processed, e.g., according to the process 400 of FIG. 4, to create a stream comprising bitumen froth passed via line 606, a stream comprising tailings passed via line 608, and a stream comprising middlings passed via line 610. Following processing in the system 300, a stream comprising middlings may be passed to the secondary extraction 602 where the middlings are further processed to create an output stream comprising flotation tailings via line 614 and an output stream comprising bitumen via line 616. Line 616 is depicted in a countercurrent configuration, returning a stream comprising bitumen froth to the input of the system 300.

|0048] In some embodiments, e.g., embodiments wherein the process 600 is placed in the context of lean froth production (LFP), the process 600 occurs substantially within a mine, e.g., to allow for reduced tailings transport for in-pit tailings disposal. In such embodiments, the process 600 may serve to perform an initial bitumen separation from sand and clay prior to transport, e.g., transporting substantially oil sand froth, and secondary processing at a geographically remote location, e.g., a central plant.

[ΘΘ49] FIG. 6B is an embodiment of an aqueous extraction process 650 for recovering hydrocarbons from a bituminous feed. The system 650 may replace a conventional froth settling unit within a Paraffin Froth Treatment (PFT) process. A PFT is a process known by those of skill in the art for separating water, solids, and asphaltenes from a solvent-diluted bitumen feed. The aqueous extraction process 650 depicts a counter-current extraction and, consequently, the process 650 comprises two separator systems 652a and 652b, e.g., each a system 300 of FIG. 3, modified as noted herein. It will be appreciated that the systems 652a and 652b each comprise a unitary outlet for middlings and/or tailings, e.g., lines 654a and 654b, respectively. The output stream comprising middlings and/or tailings passed via line 654a is passed to the system 652b, e.g., serving as the input bituminous feed into the system 652b, while the output stream comprising middlings and/or tailings passed via line 654b is passed to a tailings solvent recovery unit 658. The tailings solvent recovery unit 658 separates the received stream into a stream comprising froth treatment tailings, passed via line 660, and a stream comprising solvent, which may join with the middlings and/or tailings line 654a via line 662. The systems 652a and 652b each comprise outlets for passing bitumen separated in the systems 652a and 652b, lines 656a and 656b, respectively. Bitumen and/or bitumen froth passed via line 656a is carried to a solvent recovery unit 664, which separates the received feed into a stream comprising bitumen, passed via line 666, and a stream comprising solvent, which may join with the solvent recovery unit return line 662 via line 668. At least a portion of the bitumen and/or bitumen froth passed via line 656a may be returned to the inlet of the system 652a via line 656c.

[0050] 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.

Claims

CLAIMS What is claimed is:

1. A system for recovering hydrocarbons from a bituminous feed in an aqueous 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 claims 1 or 2, wherein at least one hopper is of a different size or shape than another hopper.

4. The system of any of claims 1-3, wherein the vessel further comprises a solvent injection inlet.

5. The system of any of claims 1-4, 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 feed in an aqueous 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, a stream comprising tailings, and a stream comprising middlings; passing the stream comprising bitumen from the vessel;

passing the stream comprising tailings from the vessel; and

passing the stream comprising middlings through an outlet of the vessel.

8. The method of claim 7, further comprising adjusting the speed of the bituminous feed flow based at least in part on the residence time required to obtain a predetermined separation.

9. The method of claims 7 or 8, further comprising passing the 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 any of claims 7-9, further comprising injecting water or a solvent into the secondary separator structure, the vessel, or both.

11. The method of any of claims 7-10, wherein the secondary separator structure comprises a plurality of second vessels each comprising at least one hopper.

12. The method of any of claims 7-11, further comprising:

passing the stream comprising middlings to an inlet of a second vessel;

passing the stream comprising middlings across a second plurality of hoppers disposed on a lower end of the second vessel;

separating stream comprising middlings to obtain additional bitumen, additional tailings, and additional middlings;

passing the additional bitumen from the second vessel;

passing the additional tailings from the second vessel; and

passing the additional middlings through an outlet of the second vessel.

13. The method of any of claims 7-12, further comprising passing at least a portion of the additional bitumen to the inlet of first vessel.

14. The method of any of claims 7-13, wherein passing the stream comprising tailings from the vessel and passing the stream comprising middlings through an outlet of the vessel occur via a unitary outlet.

15. The method of any of claims 7-14, wherein the bituminous feed comprises a bituminous froth.

16. The method according to claims 7-15, further comprising:

precipitating a portion of 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.

17. The method of any of claims 7-16, 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 of any of claims 7-17, 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.

19. A system for separating a bituminous feed in an aqueous 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 middlings 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.

20. The system of claim 19, 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.

21. The system of claim 19, further comprising a solvent recovery unit operatively coupled to at least one bitumen outlet.