CA2897842A1 - Process and apparatus for partially deasphalting bitumen - Google Patents
Process and apparatus for partially deasphalting bitumen Download PDFInfo
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- CA2897842A1 CA2897842A1 CA2897842A CA2897842A CA2897842A1 CA 2897842 A1 CA2897842 A1 CA 2897842A1 CA 2897842 A CA2897842 A CA 2897842A CA 2897842 A CA2897842 A CA 2897842A CA 2897842 A1 CA2897842 A1 CA 2897842A1
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- overflow
- pumpbox
- underflow
- hydrocyclone
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/02—General arrangement of separating plant, e.g. flow sheets specially adapted for oil-sand, oil-chalk, oil-shales, ozokerite, bitumen, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/24—Feed or discharge mechanisms for settling tanks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/24—Feed or discharge mechanisms for settling tanks
- B01D21/245—Discharge mechanisms for the sediments
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D21/00—Separation of suspended solid particles from liquids by sedimentation
- B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
- B01D21/267—Separation of sediment aided by centrifugal force or centripetal force by using a cyclone
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- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
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- Oil, Petroleum & Natural Gas (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The use of parafinnic solvent to treat mined oil sand extraction froths is a known technology. The high temperature version of the process includes a partial deasphalting of the bitumen (partial upgrading) and the production of hard, stable agglomerates of the precipitated asphaltene and mineral. In the present invention, the first stage of the process is replaced with a higher G-Force apparatus, namely a hydrocyclone, improving quality and mitigating the cost associated with large, field fabricated pressure vessels when applied to typical Canadian mined oil sands production volumes.
Description
PROCESS AND APPARATUS FOR PARTIALLY
DEASPHALTI NG BITUMEN
FIELD OF INVENTION
This invention relates to process and apparatus for the treatment of bitumen froth streams that result from oil sands mining operations, in particular the bitumen froth stream generated by warm water extraction processes.
BACKGROUND OF INVENTION
The Athabasca region of Alberta, Canada has world scale bitumen deposits, some of which can be produced efficiently through surface mining. The standard flowsheet for removing the bitumen from the sands in these "mined oil" facilities includes a water washing/flotation process that results in a frothy emulsion of the bitumen containing typically 30%
water and 10% mineral along with the bitumen and some gas.
There are a variety of methods used for cleaning this froth product, with high temperature paraffinic froth treatment recently being the preferred because it produces a very clean, partially upgraded (through asphaltene rejection) bitumen product. At typical production levels for this process, the separation vessels are very large pressure vessels, so there is interest in methods for reducing the size requirements CA 2,750,837 teaches the cleaning of oil sands froth using high temperature parafinnic solvent to partially deasphalt the bitumen and create high settling rate agglomerates allowing the cleaning of the bitumen to a fungible specification. It teaches a process with two stages of separation and counter current flow of solvent.
US 8,262,865 teaches the addition of an electrostatic precipitator to the treatment train for the separated diluted bitumen from a process such as that describes in CA
DEASPHALTI NG BITUMEN
FIELD OF INVENTION
This invention relates to process and apparatus for the treatment of bitumen froth streams that result from oil sands mining operations, in particular the bitumen froth stream generated by warm water extraction processes.
BACKGROUND OF INVENTION
The Athabasca region of Alberta, Canada has world scale bitumen deposits, some of which can be produced efficiently through surface mining. The standard flowsheet for removing the bitumen from the sands in these "mined oil" facilities includes a water washing/flotation process that results in a frothy emulsion of the bitumen containing typically 30%
water and 10% mineral along with the bitumen and some gas.
There are a variety of methods used for cleaning this froth product, with high temperature paraffinic froth treatment recently being the preferred because it produces a very clean, partially upgraded (through asphaltene rejection) bitumen product. At typical production levels for this process, the separation vessels are very large pressure vessels, so there is interest in methods for reducing the size requirements CA 2,750,837 teaches the cleaning of oil sands froth using high temperature parafinnic solvent to partially deasphalt the bitumen and create high settling rate agglomerates allowing the cleaning of the bitumen to a fungible specification. It teaches a process with two stages of separation and counter current flow of solvent.
US 8,262,865 teaches the addition of an electrostatic precipitator to the treatment train for the separated diluted bitumen from a process such as that describes in CA
2,750,837.
CA 2,746,987 teaches a method to upgrade oil sand compositions which comprises the steps of: contacting an oil sand composition with water to form an oil sand slurry;
separating the oil sand slurry into a froth containing water and hydrocarbon mixture and a underflow stream comprising solids and water; increasing the pressure of the froth to a pressure above about 22.1 MPa; heating the froth to a temperature above about 374 C; allowing the froth to remain at a pressure above about 22.1MPa and a temperature above about 374 C for a period long enough for the hydrocarbons in the froth to be at least partially upgraded to become an upgraded froth; and to separate the upgraded froth into an upgraded hydrocarbon stream and an stream containing water, solids and asphaltenes.
It is stated that the required temperature and pressure are the critical temperature and pressure for water. Hydrocarbons in the froth become miscible in water when the water is at supercritical conditions.
CA 2,638,120 teaches a process using a primary settler to produce an overflow stream of primary raw dilbit, comprising bitumen containing water and some fine solids, and an underflow stream of primary tails, comprising solids, water and residual bitumen;
removing the overflow stream of primary raw dilbit and subjecting it to gravity settling in a clarifier vessel for sufficient time to produce an overflow first stream of cleaned dilbit and an underflow stream of clarifier sludge; diluting the primary tails with hydrocarbon diluents and subjecting the diluted primary tails to gravity settling in a secondary settler to produce an overflow second stream of cleaned dilbit and an underflow stream of secondary tails; and removing the clarifier sludge and diluting the clarifier sludge with a hydrocarbon diluent, if necessary, and subjecting the clarifier sludge to gravity separation to produce a third stream of cleaned dilbit. It is stated that in one embodiment the clarifier sludge is subjected to gravity separation in a centrifuge, for example, a disc centrifuge, a scroll centrifuge or a series of disc and/or scroll centrifuges. In another embodiment, other gravity separation means known in the art can be used such as hydrocyclones, cycloseparators, propelled vortex separators and the like.
CA 2,610,122 teaches an extraction system for extracting bitumen froth from a slurry containing bitumen, solids and water comprising: a cyclone separation facility for separating the slurry into a solids component stream and a bitumen froth stream, the bitumen froth stream including bitumen, water and fine solids; and a froth concentration facility for separating the bitumen froth stream into a final bitumen enriched froth stream, and a water and fine solids stream.
It had been proposed in a paper by Madge and Garner that the use of a hydrocyclone in paraffinic froth treatment (in general) could improve the solvent requirement for the asphaltene precipitation (less solvent required for the same level of precipitation) which would result in knock-on improvements in the downstream processes. However, they had not considered the use of a hydrocyclone as the first stage separator.
Despite the number of available processes, there is still a need for a more efficient process to remove contaminants from the bitumen froth generated during paraffinic froth treatment. The present invention provides means for improved creation and management of the agglomerates in the first stage of the process allowing for more subtle downstream processing of any remaining water. It also addresses a pragmatic issue in the scale of minable oil sands, that being the size of the separation vessels (and thus the direct logistics of their fabrication/transport and siting). This has knock-on impacts in the management of flammable inventories, flare sizing, blast and jet fire radii and de-inventory volumes.
SUMMARY OF THE INVENTION
The present invention is applied to the sequential separation of bitumen from gangue materials left over by the warm water extraction process use for oil sands in the Athabasca region of Canada. This process uses a counter-current flow of paraffinic solvent in 2 stages to clean the mineral and water of maltene (the non-asphaltene component of bitumen) content, then to clean the bitumen product of mineral, water and some of its asphaltene.
There are standard concerns with the use of a hydrocyclone in this manner. In particular, the split needs to be managed around a feed whose bulk composition varies quite substantially and there is an inherent lack of equalization. In the proposed apparatus and flowsheet this is managed by the normally applied manipulation of the dead-band pressure for the cyclopack in combination with, the addition of free water to provide a volumetric phase buffer and the use of a secondary separation in the overflow pumpbox which allows the management of water overflow in the event of poor equalization.
CA 2,746,987 teaches a method to upgrade oil sand compositions which comprises the steps of: contacting an oil sand composition with water to form an oil sand slurry;
separating the oil sand slurry into a froth containing water and hydrocarbon mixture and a underflow stream comprising solids and water; increasing the pressure of the froth to a pressure above about 22.1 MPa; heating the froth to a temperature above about 374 C; allowing the froth to remain at a pressure above about 22.1MPa and a temperature above about 374 C for a period long enough for the hydrocarbons in the froth to be at least partially upgraded to become an upgraded froth; and to separate the upgraded froth into an upgraded hydrocarbon stream and an stream containing water, solids and asphaltenes.
It is stated that the required temperature and pressure are the critical temperature and pressure for water. Hydrocarbons in the froth become miscible in water when the water is at supercritical conditions.
CA 2,638,120 teaches a process using a primary settler to produce an overflow stream of primary raw dilbit, comprising bitumen containing water and some fine solids, and an underflow stream of primary tails, comprising solids, water and residual bitumen;
removing the overflow stream of primary raw dilbit and subjecting it to gravity settling in a clarifier vessel for sufficient time to produce an overflow first stream of cleaned dilbit and an underflow stream of clarifier sludge; diluting the primary tails with hydrocarbon diluents and subjecting the diluted primary tails to gravity settling in a secondary settler to produce an overflow second stream of cleaned dilbit and an underflow stream of secondary tails; and removing the clarifier sludge and diluting the clarifier sludge with a hydrocarbon diluent, if necessary, and subjecting the clarifier sludge to gravity separation to produce a third stream of cleaned dilbit. It is stated that in one embodiment the clarifier sludge is subjected to gravity separation in a centrifuge, for example, a disc centrifuge, a scroll centrifuge or a series of disc and/or scroll centrifuges. In another embodiment, other gravity separation means known in the art can be used such as hydrocyclones, cycloseparators, propelled vortex separators and the like.
CA 2,610,122 teaches an extraction system for extracting bitumen froth from a slurry containing bitumen, solids and water comprising: a cyclone separation facility for separating the slurry into a solids component stream and a bitumen froth stream, the bitumen froth stream including bitumen, water and fine solids; and a froth concentration facility for separating the bitumen froth stream into a final bitumen enriched froth stream, and a water and fine solids stream.
It had been proposed in a paper by Madge and Garner that the use of a hydrocyclone in paraffinic froth treatment (in general) could improve the solvent requirement for the asphaltene precipitation (less solvent required for the same level of precipitation) which would result in knock-on improvements in the downstream processes. However, they had not considered the use of a hydrocyclone as the first stage separator.
Despite the number of available processes, there is still a need for a more efficient process to remove contaminants from the bitumen froth generated during paraffinic froth treatment. The present invention provides means for improved creation and management of the agglomerates in the first stage of the process allowing for more subtle downstream processing of any remaining water. It also addresses a pragmatic issue in the scale of minable oil sands, that being the size of the separation vessels (and thus the direct logistics of their fabrication/transport and siting). This has knock-on impacts in the management of flammable inventories, flare sizing, blast and jet fire radii and de-inventory volumes.
SUMMARY OF THE INVENTION
The present invention is applied to the sequential separation of bitumen from gangue materials left over by the warm water extraction process use for oil sands in the Athabasca region of Canada. This process uses a counter-current flow of paraffinic solvent in 2 stages to clean the mineral and water of maltene (the non-asphaltene component of bitumen) content, then to clean the bitumen product of mineral, water and some of its asphaltene.
There are standard concerns with the use of a hydrocyclone in this manner. In particular, the split needs to be managed around a feed whose bulk composition varies quite substantially and there is an inherent lack of equalization. In the proposed apparatus and flowsheet this is managed by the normally applied manipulation of the dead-band pressure for the cyclopack in combination with, the addition of free water to provide a volumetric phase buffer and the use of a secondary separation in the overflow pumpbox which allows the management of water overflow in the event of poor equalization.
3 The process according to a preferred embodiment of the present invention uses a counter-current flow of paraffinic solvent in 2 stages to clean the bitumen product of mineral, water and some of its asphaltene.
The process according to a preferred embodiment of the present invention uses a hydrocyclone to replace the first stage settler (in which the bitumen stream is cleaned). This reduces the requirement for a large pressure vessel and improves the product quality because of the higher G-force separation. Preferably, the proposed process and apparatus can also manage the split needs by the manipulation of the dead-band pressure for the cyclopack in combination with, the addition of water to provide a separation phase and the use of a secondary separation in the overflow pumpbox which allows the management of water overflow in the event of poor equalization.
Pump boxes are a common piece of equipment in the processing industry and are used to allow for controlled feed rates through a pump, in other words some equalization of upstream flow to the pumped flow. In our case the sizing of the pump box, though based on allowing for a secondary separation (water from product) is not particularly different than would be required for its primary purpose of flow equalization.
According to a preferred embodiment of the present invention, the process improves the initial separation both from a size/density perspective (resulting in moderately cleaner product) and from a loading (quantity and quality) perspective, as the great bulk of agglomerates produced through the precipitation of asphaltene will be immediately directed to the first stage underflow stream and the remaining material is less likely to foul any internals in the pump box. It also has merit from a mixing energy perspective which has been shown to benefit the high temperature paraffinic froth treatment process.
BRIEF DESCRIPTION OF THE FIGURES
The invention may be more completely understood in consideration of the following description of various embodiments of the invention in connection with the accompanying figure, in which:
The process according to a preferred embodiment of the present invention uses a hydrocyclone to replace the first stage settler (in which the bitumen stream is cleaned). This reduces the requirement for a large pressure vessel and improves the product quality because of the higher G-force separation. Preferably, the proposed process and apparatus can also manage the split needs by the manipulation of the dead-band pressure for the cyclopack in combination with, the addition of water to provide a separation phase and the use of a secondary separation in the overflow pumpbox which allows the management of water overflow in the event of poor equalization.
Pump boxes are a common piece of equipment in the processing industry and are used to allow for controlled feed rates through a pump, in other words some equalization of upstream flow to the pumped flow. In our case the sizing of the pump box, though based on allowing for a secondary separation (water from product) is not particularly different than would be required for its primary purpose of flow equalization.
According to a preferred embodiment of the present invention, the process improves the initial separation both from a size/density perspective (resulting in moderately cleaner product) and from a loading (quantity and quality) perspective, as the great bulk of agglomerates produced through the precipitation of asphaltene will be immediately directed to the first stage underflow stream and the remaining material is less likely to foul any internals in the pump box. It also has merit from a mixing energy perspective which has been shown to benefit the high temperature paraffinic froth treatment process.
BRIEF DESCRIPTION OF THE FIGURES
The invention may be more completely understood in consideration of the following description of various embodiments of the invention in connection with the accompanying figure, in which:
4 Figure 1 is a schematic showing the apparatus according to a preferred embodiment of the present invention for treating a bitumen froth stream;
Figure 2 is a cross-sectional view of the hydrocyclone illustrating the internal stream flow;
Figure 3 is a side view of the pumpbox according to a preferred embodiment of the present invention showing the inclined plates;
Figure 4 is a close up view of the inclined plates in the pumpbox according to a preferred embodiment of the present invention;
Figure 5 is top view of the plate pack inside the pumpbox according to a preferred embodiment of the present invention;
Figure 6 is a schematic representation of the flow and separation at the inclined plates; and Figure 7 is a schematic representation of the flow and separation at the inclined plates.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 provides a preferred embodiment of the process according to the present invention.
This schematic shows the overall process layout of the two stage froth treatment circuit.
Froth (101) is fed into the front of the process where it meets an "intermediate solvent"
(102), which is overflow from the second stage settler. Water (103) may also be added at this point to provide an appropriate split volume (one that falls within a reasonable operating range for the cyclone). This mixture passes to the cyclo-pack distributor (104) from which it is directed to one of many cyclones (105). The underflow (155 not shown) from the cyclone passes to the underflow launder (106). The overflow (165 not shown) is directed to the knuckle of the overflow pump box (107) and redirected into the horizontal plane allowing it to slow and separate. The free water in this stream can drop immediately into the cone of the pump box. The remaining hydrocarbon rises through the column of the pump box, and water droplets continue to drain from it. It passes over the internal weir (128) of the overflow launder (108) and proceeds to product (109).
The pump box underflow (110) is Erected to the hydrocyclone underflow stream (111) and together, after contact with fresh solvent (112) such as distilled pentane, they are directed to a conventional second stage settler (113). The overflow of the second stage settler goes through an accumulator (114) and goes back as stream (102) to the hydrocyclone feed (101) as the intermediate solvent. Intermediate solvent is pentane which has been in contact with bitumen and contains some maltenes. The underflow (115) of the second stage settler (113) goes to a tailing solvent recovery unit.
The stream flow inside of a hydrocyclone is shown in Figure 2. A cyclone separates the mixed feed (201) by a combination of g forces, higher than unity g force towards the wall and a single g towards the vertical base. The vertical separation is coupled with the 1 g gradient through the cyclone and the height of the end weirs, which are the Apex (202) and Vortex Finder (203). The separation occurs over a short distance, parallel to the main g force. The retention time for the separation is perpendicular to the main g-force direction. Manipulating the diameter and length result in the desired degree of separation.
Segregation is achieved by the balance or split between the dense phase (204) and light phase (205) flows. The apex flow (at 202) is substantially fixed, while the flow through the vortex finder (at 203) is a function of the pressure drop through the cyclone. The pressure drop through the hydrocyclone is manipulated by managing the volume fed to the hydrocyclone, which in turn, is managed by manipulating the number of cyclones processing a given volume of fluid. The addition of water can allow for complete segregation of the light and dense phases by allowing water to split in both directions. Therefore, according to a preferred embodiment of the present invention, the split in the hydrocyclones is managed through feed pressure dead-band and water addition.
A plate pack (301) which can be used to "polish" the hydrocarbon of water droplets (302) is shown in Figure 3. These plates convert the feed flow (303), coming from the bottom portion of the pumpbox, from vertical to the equivalent of horizontal, removing the upward flux from resisting the droplet settling. The plate pack is substantially rectangular and is fed from the chord of the vessel through plate side slots (304). The overflow (305) is directed to the product launder and the underflow is directed to the vessel wall, where the fine droplets (302) containing mostly water and fine solids are directed downwards through gravity and are unlikely to be re-entrained.
The inlet feed from the hydrocyclone overflow is located in the lower section of the pumpbox with the feed horizontally directed. The positioning of the feed is preferably done to prevent unnecessary mixing of the already separated water droplets with the incoming high hydrocarbon content stream and therefore allow for the most efficient separation of hydrocarbon and water inside a vessel containing as few internals as possible.
The mechanism of the inclined plate separation is explained in Figures 6 and 7.
Conventional separators are classified in two broad categories: vertical (401) and horizontal (402).
As is well understood by the person skilled in the art, vertical vessels handle difficult materials and solids better than horizontal vessels due to the relative lack of horizontal build-up points. As is also known in the art, horizontal vessels have the advantage that the vertical flux that must be overcome by a droplet passing through the bulk flow is roughly zero. Inclined plates (403) behave in separation similarly to a horizontal settler as the plates remain in a consistent vertical position relative to the bulk flow for an equivalent of zero vertical flux. At the same time, the plates sloped surface allows for the bulk gravity transport of solids and other dense phase materials which would otherwise not flow in a horizontal settler. Inclined plates also allow for the stacking of cross sectional area. As is well understood by the person skilled in the art, the final selection of separator format is a function of materials handling, final size of equipment, and confidence in the engineering, resulting in a lowest cost/risk mix.
Preferably, the second stage settler comprises inclined plates therein to improve the throughput to diameter ratio for that vessel.
Preferably, the hydrocyclones are in the size range of 10-26 inches.
Preferably also, the dead-band and water control are adapted to maintain a split with greater than 85% of the "cleaned hydrocarbon phase" going to overflow. This provides for a final pumped overflow stream having a mineral inclusion of less than 500 ppm. In a preferred embodiment, the overflow pumpbox is equipped with downcomers for the hydrocyclone overflow and product is released over a weir such that tramp material remains in the bottom of the pump box and is thus segregated from the product.
More preferably, the pumpbox comprises a second outlet on the pumpbox through which tramp material can be directed to a second stage if processing.
According to a preferred embodiment, there is provided a fluid connection between the overflow of the settling vessel (second stage settler accumulator vessel) and the inlet feed. This provides a two-fold advantage of re-processing the extracted bitumen from the last separation unit (the settling vessel according to the embodiment of Figure 1) and dilution of the incoming feed prior to entering the first separation stage (consisting of a hydrocyclone as per the embodiment illustrated in Figure 1).
The present invention provides for an advantageous method of aggressively treating paraffinic froth treatment tailings by subjecting the latter to a first stage of high efficiency separation and further subjecting the tailings from the first stage to a second treatment stage comprising a settling stage thereby enhancing bitumen recovery.
The embodiments described herein are to be understood to be exemplary and numerous modification and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the claims appended hereto, the invention may be practiced otherwise than as specifically disclosed herein.
Figure 2 is a cross-sectional view of the hydrocyclone illustrating the internal stream flow;
Figure 3 is a side view of the pumpbox according to a preferred embodiment of the present invention showing the inclined plates;
Figure 4 is a close up view of the inclined plates in the pumpbox according to a preferred embodiment of the present invention;
Figure 5 is top view of the plate pack inside the pumpbox according to a preferred embodiment of the present invention;
Figure 6 is a schematic representation of the flow and separation at the inclined plates; and Figure 7 is a schematic representation of the flow and separation at the inclined plates.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 provides a preferred embodiment of the process according to the present invention.
This schematic shows the overall process layout of the two stage froth treatment circuit.
Froth (101) is fed into the front of the process where it meets an "intermediate solvent"
(102), which is overflow from the second stage settler. Water (103) may also be added at this point to provide an appropriate split volume (one that falls within a reasonable operating range for the cyclone). This mixture passes to the cyclo-pack distributor (104) from which it is directed to one of many cyclones (105). The underflow (155 not shown) from the cyclone passes to the underflow launder (106). The overflow (165 not shown) is directed to the knuckle of the overflow pump box (107) and redirected into the horizontal plane allowing it to slow and separate. The free water in this stream can drop immediately into the cone of the pump box. The remaining hydrocarbon rises through the column of the pump box, and water droplets continue to drain from it. It passes over the internal weir (128) of the overflow launder (108) and proceeds to product (109).
The pump box underflow (110) is Erected to the hydrocyclone underflow stream (111) and together, after contact with fresh solvent (112) such as distilled pentane, they are directed to a conventional second stage settler (113). The overflow of the second stage settler goes through an accumulator (114) and goes back as stream (102) to the hydrocyclone feed (101) as the intermediate solvent. Intermediate solvent is pentane which has been in contact with bitumen and contains some maltenes. The underflow (115) of the second stage settler (113) goes to a tailing solvent recovery unit.
The stream flow inside of a hydrocyclone is shown in Figure 2. A cyclone separates the mixed feed (201) by a combination of g forces, higher than unity g force towards the wall and a single g towards the vertical base. The vertical separation is coupled with the 1 g gradient through the cyclone and the height of the end weirs, which are the Apex (202) and Vortex Finder (203). The separation occurs over a short distance, parallel to the main g force. The retention time for the separation is perpendicular to the main g-force direction. Manipulating the diameter and length result in the desired degree of separation.
Segregation is achieved by the balance or split between the dense phase (204) and light phase (205) flows. The apex flow (at 202) is substantially fixed, while the flow through the vortex finder (at 203) is a function of the pressure drop through the cyclone. The pressure drop through the hydrocyclone is manipulated by managing the volume fed to the hydrocyclone, which in turn, is managed by manipulating the number of cyclones processing a given volume of fluid. The addition of water can allow for complete segregation of the light and dense phases by allowing water to split in both directions. Therefore, according to a preferred embodiment of the present invention, the split in the hydrocyclones is managed through feed pressure dead-band and water addition.
A plate pack (301) which can be used to "polish" the hydrocarbon of water droplets (302) is shown in Figure 3. These plates convert the feed flow (303), coming from the bottom portion of the pumpbox, from vertical to the equivalent of horizontal, removing the upward flux from resisting the droplet settling. The plate pack is substantially rectangular and is fed from the chord of the vessel through plate side slots (304). The overflow (305) is directed to the product launder and the underflow is directed to the vessel wall, where the fine droplets (302) containing mostly water and fine solids are directed downwards through gravity and are unlikely to be re-entrained.
The inlet feed from the hydrocyclone overflow is located in the lower section of the pumpbox with the feed horizontally directed. The positioning of the feed is preferably done to prevent unnecessary mixing of the already separated water droplets with the incoming high hydrocarbon content stream and therefore allow for the most efficient separation of hydrocarbon and water inside a vessel containing as few internals as possible.
The mechanism of the inclined plate separation is explained in Figures 6 and 7.
Conventional separators are classified in two broad categories: vertical (401) and horizontal (402).
As is well understood by the person skilled in the art, vertical vessels handle difficult materials and solids better than horizontal vessels due to the relative lack of horizontal build-up points. As is also known in the art, horizontal vessels have the advantage that the vertical flux that must be overcome by a droplet passing through the bulk flow is roughly zero. Inclined plates (403) behave in separation similarly to a horizontal settler as the plates remain in a consistent vertical position relative to the bulk flow for an equivalent of zero vertical flux. At the same time, the plates sloped surface allows for the bulk gravity transport of solids and other dense phase materials which would otherwise not flow in a horizontal settler. Inclined plates also allow for the stacking of cross sectional area. As is well understood by the person skilled in the art, the final selection of separator format is a function of materials handling, final size of equipment, and confidence in the engineering, resulting in a lowest cost/risk mix.
Preferably, the second stage settler comprises inclined plates therein to improve the throughput to diameter ratio for that vessel.
Preferably, the hydrocyclones are in the size range of 10-26 inches.
Preferably also, the dead-band and water control are adapted to maintain a split with greater than 85% of the "cleaned hydrocarbon phase" going to overflow. This provides for a final pumped overflow stream having a mineral inclusion of less than 500 ppm. In a preferred embodiment, the overflow pumpbox is equipped with downcomers for the hydrocyclone overflow and product is released over a weir such that tramp material remains in the bottom of the pump box and is thus segregated from the product.
More preferably, the pumpbox comprises a second outlet on the pumpbox through which tramp material can be directed to a second stage if processing.
According to a preferred embodiment, there is provided a fluid connection between the overflow of the settling vessel (second stage settler accumulator vessel) and the inlet feed. This provides a two-fold advantage of re-processing the extracted bitumen from the last separation unit (the settling vessel according to the embodiment of Figure 1) and dilution of the incoming feed prior to entering the first separation stage (consisting of a hydrocyclone as per the embodiment illustrated in Figure 1).
The present invention provides for an advantageous method of aggressively treating paraffinic froth treatment tailings by subjecting the latter to a first stage of high efficiency separation and further subjecting the tailings from the first stage to a second treatment stage comprising a settling stage thereby enhancing bitumen recovery.
The embodiments described herein are to be understood to be exemplary and numerous modification and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the claims appended hereto, the invention may be practiced otherwise than as specifically disclosed herein.
Claims (16)
1. A high temperature paraffinic froth treatment process in which the froth is first sent to a hydrocyclone to produce:
- an overflow stream containing a highly refined hydrocarbon phase containing more than 99.8% hydrocarbon with less than 500ppm of mineral and free water and - a low hydrocarbon content underflow stream;
the underflow stream is sent to a settling vessel and the overflow is sent to a pumpbox, said pumpbox comprising at least one oil/water separator to separate hydrocarbons from water and other impurities; said overflow stream being injected at a lower section of the pumpbox and the hydrocarbons, water and solids being further separated in part, by settling and, in part, by exposure to the oil/water separator.
- an overflow stream containing a highly refined hydrocarbon phase containing more than 99.8% hydrocarbon with less than 500ppm of mineral and free water and - a low hydrocarbon content underflow stream;
the underflow stream is sent to a settling vessel and the overflow is sent to a pumpbox, said pumpbox comprising at least one oil/water separator to separate hydrocarbons from water and other impurities; said overflow stream being injected at a lower section of the pumpbox and the hydrocarbons, water and solids being further separated in part, by settling and, in part, by exposure to the oil/water separator.
2. The process according to claim 1, wherein the overflow is directed to the lower section of a pumpbox and subjected to a settling step for removal of water and other contaminants in the overflow.
3. The process according to claim 2, wherein the separation by the oil/water separator involves the upward movement of hydrocarbons through the oil/water separator and enhanced separation and/or the coalescing thereof on the separator combined with the downward movement of water and solids through the separator.
4. The process according to claim 2, wherein the settling step comprises a discharge of the underflow from the pumpbox towards a settling vessel.
5. The process according to claim 4, wherein the underflow from the pumpbox is combined with the underflow from the hydrocyclone prior to entering the settling vessel.
6. The process according to claim 5, wherein the underflow from the pumpbox, combined with the underflow from the hydrocyclone are further mixed with additional solvent prior to entering the settling vessel.
7. A process according to claim 1 where the overflow stream from the hydrocyclone is directed to the lower portion of the overflow pumpbox and the final product is removed via an overflow launder in the overflow pumpbox.
8. A process according to any one of claims 4 to 6 where tramp material separated from the overflow stream in the overflow pumpbox bottom is directed to the second stage settler.
9. An apparatus for the partial deasphalting of bitumen comprising:
- a froth feed;
- a hydrocyclone fluidly connected to the froth feed; said hydrocyclone comprising an inlet, an overflow and an underflow, said underflow being in fluid communication with a settling vessel; and - a pumpbox fluidly connected to the overflow of the hydrocyclone.
- a froth feed;
- a hydrocyclone fluidly connected to the froth feed; said hydrocyclone comprising an inlet, an overflow and an underflow, said underflow being in fluid communication with a settling vessel; and - a pumpbox fluidly connected to the overflow of the hydrocyclone.
10. The apparatus according to claim 9, further comprising an oil/water separator positioned inside the pumpbox above the feed from the hydrocyclone overflow.
11. The apparatus according to claim 10 further comprising a product launder comprising a vertical weir positioned above a top edge of the oil/water separator.
12. The apparatus according to claim 9 further comprising an underflow hydrocyclone launder adapted to collect the underflow from he hydrocyclone and direct it to a second stage settler.
13. The apparatus according to claim 12 wherein the second stage settler comprises an underflow fluidly connected to a tailings solvent recovery unit.
14. The apparatus according to claim 13 wherein the second stage settler comprises an overflow fluidly connected to an accumulator fluidly connected to the froth feed
15. The apparatus according to any one of claims 9 to 14, where the overflow of the pumpbox further comprises inclined plates adapted to remove impurities from the dissolved bitumen.
16. The apparatus according to any one of claims 9 to 15, further comprising a fluid connection between the overflow of the settling vessel and the inlet feed.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2897842A CA2897842A1 (en) | 2015-07-21 | 2015-07-21 | Process and apparatus for partially deasphalting bitumen |
| CA2936316A CA2936316C (en) | 2015-07-21 | 2016-07-18 | Process and apparatus for partially deasphalting bitumen |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2897842A CA2897842A1 (en) | 2015-07-21 | 2015-07-21 | Process and apparatus for partially deasphalting bitumen |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2897842A1 true CA2897842A1 (en) | 2017-01-21 |
Family
ID=57810240
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2897842A Abandoned CA2897842A1 (en) | 2015-07-21 | 2015-07-21 | Process and apparatus for partially deasphalting bitumen |
| CA2936316A Active CA2936316C (en) | 2015-07-21 | 2016-07-18 | Process and apparatus for partially deasphalting bitumen |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2936316A Active CA2936316C (en) | 2015-07-21 | 2016-07-18 | Process and apparatus for partially deasphalting bitumen |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA2897842A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10954448B2 (en) | 2017-08-18 | 2021-03-23 | Canadian Natural Resources Limited | High temperature paraffinic froth treatment process |
| US11001762B2 (en) | 2017-04-06 | 2021-05-11 | Suncor Energy Inc. | Partial upgrading of bitumen with thermal treatment and solvent deasphalting |
-
2015
- 2015-07-21 CA CA2897842A patent/CA2897842A1/en not_active Abandoned
-
2016
- 2016-07-18 CA CA2936316A patent/CA2936316C/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11001762B2 (en) | 2017-04-06 | 2021-05-11 | Suncor Energy Inc. | Partial upgrading of bitumen with thermal treatment and solvent deasphalting |
| US10954448B2 (en) | 2017-08-18 | 2021-03-23 | Canadian Natural Resources Limited | High temperature paraffinic froth treatment process |
Also Published As
| Publication number | Publication date |
|---|---|
| CA2936316C (en) | 2023-09-19 |
| CA2936316A1 (en) | 2017-01-21 |
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