CA2305407C - Three-phase rotary separator - Google Patents
Three-phase rotary separator Download PDFInfo
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- CA2305407C CA2305407C CA002305407A CA2305407A CA2305407C CA 2305407 C CA2305407 C CA 2305407C CA 002305407 A CA002305407 A CA 002305407A CA 2305407 A CA2305407 A CA 2305407A CA 2305407 C CA2305407 C CA 2305407C
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Abstract
The method of operating rotating separator apparatus, to which fluid, including gas and liquids is supplied in a fluid jet at via a nozzle, which includes separating the liquids from the gas in the stream, at a first zone within the rotating appratus, and separating the liquids into liquids of differing density at a second zone within the apparatus.
Description
THREE-PHASE ROTARY SEPARATOR
BACKGROUND OF THE INVENTION
This invention relates generally to separation of three fluid phases-gas, oil and water, and more particularly concerns achieving such separation using rotating separator apparatus. In addition, the invention concerns methods of operating rotary separator apparatus in relation to scoop means immersed in a liquid ring on the rotary separator. Solids entrained in the flow must also be separated.
In existing non-rotary methods, a large gravity separation tank is required to be used, and only partial separation of oil and water phases is achievable. Therefore, additional treatment is required for separating those constituents. Secondary treatment methods require expenditure of large amounts of power, as for example via high speed centrifuges.
Another advantage is the size and weight of the required vessels.
For offshore oil and gas productions, the large separation vessels require large, expensive structures to support their weight.
From US-A-4,087,261 there is known a rotating separator apparatus which shows scoops fully submerged in the apparatus to remove separated liquids. As shown, the flowrate from a fully submerged scoop is fixed by the liquid velocity and the scoop inlet area. Increases in flowrate would cause the liquid entering a particular submerged scoop to overflow it and go into another scoop. Decreases in flowrate would cause the scoop to take in additional liquid from another zone.
BACKGROUND OF THE INVENTION
This invention relates generally to separation of three fluid phases-gas, oil and water, and more particularly concerns achieving such separation using rotating separator apparatus. In addition, the invention concerns methods of operating rotary separator apparatus in relation to scoop means immersed in a liquid ring on the rotary separator. Solids entrained in the flow must also be separated.
In existing non-rotary methods, a large gravity separation tank is required to be used, and only partial separation of oil and water phases is achievable. Therefore, additional treatment is required for separating those constituents. Secondary treatment methods require expenditure of large amounts of power, as for example via high speed centrifuges.
Another advantage is the size and weight of the required vessels.
For offshore oil and gas productions, the large separation vessels require large, expensive structures to support their weight.
From US-A-4,087,261 there is known a rotating separator apparatus which shows scoops fully submerged in the apparatus to remove separated liquids. As shown, the flowrate from a fully submerged scoop is fixed by the liquid velocity and the scoop inlet area. Increases in flowrate would cause the liquid entering a particular submerged scoop to overflow it and go into another scoop. Decreases in flowrate would cause the scoop to take in additional liquid from another zone.
SUMMARY OF THE INVENTION
it is a major object of the invention to provide a simple, effective method and appa.ratus meeting the above needs.
According to the present invention, there is provided a method of operating a rotating separator apparatus, to which fluid including gas and liquid is supplied in a fluid jet as via a nozzle , the method comprising the steps of providing at said apparatus an outlet for flowing li(juid A of higher density, and providing at said apparatus an outlet for flowing liquid B of lesser density, said liquids A and B having a stable interface location determined by the relative locations of said outlets, providing at least one of said outlets in the form of a scoop immersed in at least one of said liquids collecting as a centrifugally-induced liquidous ring travelling relative to the scoop, and further a) separating the liquids from the gas in said stream, at a first zone within said rotating apparatus, b) separating the liquids into liquids of differing density at a second zone within said apparatus, c) said separating including providing a scoop immersed in at least one of said liquids traveling relative to the scoop, the method being characterised by the further step of d) providing a movable inlet barrier in association with the scoop to block entry of gas into the scoop.
According to the present invention, there is also provided a rotating separator apparatus comprising means as a nozzle to supply a fluid including gas and liquid to the separator, the separator further comprising an outlet for flowing liquid A of higher density, and an outiet for flowing liquid B of lesser density, said liquids A and B having a stable interface location determined by the relative locations of said outlets, at least one of said outlets having the form of a scoop immersed in at least one of said liquids collecting as a centrifugally-2a induced liquidous ring travelling relative to the scoop, the apparatus further camprising a) means for separating the liquids from the gas in said stream, at a first zone within said rotating apparatus, b) means for separating the liquids into liquids of differing density at a second zone within said apparatus, c) means for said separating including a scoop immersed in at least one of said liquids travelling relative to the scoop, and being characterized by d) a movable inlet barrier in association with the scoop to block entry of gas into the scoop.
it is another object to provide method and apparatus to achieve complete separation of- gas, oil, water, and solids. It operates either by the two-phase' fluid energy or by a supplementary motor drive. It has a self-regulating featuze to handle widely varying ratios of gas, oil and water with no externa:L controls.
A further olaject concerns removal from the fluid jet of entrained solid parti.cles, the method including providing a solids removal passage in" the rotating-separator apparatus, and including separating i . , i J . . , = , . . .
t . 1'= . a r . ' ' i ' . t i ' , t '.
~the particles which are separated. by transfer to the passage.
Yet another object includes provision at the rotating separator apparatus of a passage for receiving a liquid A of higher density, providing at the apparatus an outlet for liquid A, and providing at the apparatus an outlet for liquid B of lesser density, the liquids A and B having a stable interface location determined by the relative locations of the outlets and passage, such that substantially complete separation of flowing liquids A
and B occurs for a relatively wide range of flows. At least one of the outlets may advantageously be in the form of a scoop immersed in at least one of the liquids flowing as in a liquidous ring relative to the scoop. A
movatie barrier may be provided in association k ith the scoop to block entry of gas into the scoop.
An additional object includes supporting the barrier for movement in response to changes in force applied to the barrier by at least one of the liquids flowing relative to the scoop.
A still further object includes providing one or more of the outlets at the rotating separator apparatus to have the form of an open weir, and flowing liquid via that weir to a passage leading to a liquid nozzle, as will be described.
Finally, it is an object of the invention to provide for liquid leaving the nozzle in the form of a jet producing thrust, and including transferring the thrust to the rotating separator apparatus.
ey These and other objects and advantages of the . ~..a-..-' . .. . ..õ.tito .. __"x . . -. ....
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.. ... ..
invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which:
DRAWING DESCRIPTION
Fig. 1 is a sectional view, i.e., an axial radial plane, of three-phase rotary apparatus incorporating the invention;
Fig. 1 a is a view like Fig. 1;
Fig. 2 is a fragmentary section showing details of a scoop having an entrained immersed in a rotating ring of liquids, and taken in a plane normal to the axis of separator rotation;
Fig. 3 is a fragmentary section taken on lines 3-3 of Fig. 2;
Fig. 4 is a view like Fig. 2 showing a modification;
Fig. 5 is a view taken on lines 5-5 of Fig. 4; and Fig. 6 is a fragmentary section showing an open weir outlet to a liquid nozzle.
DETAILED DESCRIPTION
Fig. 1 shows a version of the three-phase rotary separator structure 32. A mixture of oil, gas and water is expanded in nozzle 17. The resulting gas and liquid jet 1 is well collimated. The jet impinges generally tangentially onto a moving (rotating) surface 2. As shown in U.S. Patent 5,385,446, the surface is solid with holes 3, to permit drainage of the liquids and solids. Surface 2 is defined by the inner side of a rotating separator annulus 2a connected as by rotor 8 and structure 31 to a rotating shaft 19 of structure 32. Shaft bearings are shown at=
locations l3a. The moving surface may alternatively be comprised of the separated liquid, in which case no solid surface 2 is required. -The centrifugal force field acting on the gas and liquid jet, when it impacts the moving surface, causes an immediate radially inward separation of the gas from the liguids. The separated gas flows through gas blades 3 in the Yotor 8, transferring power to the rotor and shaft 19. The gas leaves through an exit port 18.
Blades 9 are.spaced about the rotor axis 19b.
The oil and water, and any particulate solids, flow into the. space between the outer wall 20 and the separating surface 2, in the, centrifugal force field.
The grea-ter density of water causes it to acquire a radial outwar-d velocity and separate from the oil f low 4.
Separated water is indicated at S. The separating oil and water flow axially through slots at location 3a in the rotor, toward the oil outlet 10, and toward the water outlet 13, respectively.
If the tangential velocity of the gas and liquid jet 1 impinging on the separating surface 2 i s greater than the rotating surface speed, the liquids wi.3_l..
be slowed by frictional forces transferring power to the PC'I'/N097/00267 . . E'' . . . Q . , , < < . , , . .
separating surface and hence to the rotor and shaft. Zf the tangential velocity of the jet is lower than the desired rotating surface speed, external power must be transferred to the shaft, and hence rotor and separating surface, to drag the slower liquids up to the speed of the rotating surface. The power can be transferred, for example by a motor, or by the shaft of another rotary separator.
The solids, being heavier than the water, are thrown to the inner side of the wall 20. The solids are collected at the farthest radial position 6 of that wall, and flow at 21 with a small amount of water into a volute 22 from which they are discharged.
A barrier 12 to the balance of the water and cll- flow-ng --g'tGFardlV_.,_..: s tile water to flow through structure-defined passages 23 located below (outwardly of ) the water-oil interface 7, formed by the centrifugal force field.
The relative placement of the oil outlet 10 in the oil collection zone 10a, and the water outlet 13, in the water collection zone 13a beyond barrier 12 causes the oil-water interface 7a to form at a location radially outward of both the oil outlet and the water outlet, but which is radially inward from the water passages 23.
This location of the rotating interface at 7a effects separation of the oil and water. Note that interface 7a intersects barrier 12, and that 2ones 10a and 13a are at opposite axial sides of barrier 12. The interface radial location is determined by the following relation, listing dimensions as shown in Fig. 1a:
C~ .
~}d ~~ '-4vnra~ua?4cImCIm~TM ..=-. '_ . .-, . . . . . . , h_ . .: . , - ",rr.... ..._, . -.._...._...._.--. ns..rrrs-"~'~~~.~... tF. _ poW ( r2s - r2o )= P~,m ( r't2_r2~ ) where p, = oil density põ = water density m = rpm of surface 2 ri = radius to oil - water interface r, = radius to oil outlet rõ = radius to water outlet The interface location is independent of the relative amounts of water and oil, so long as the pressure drop of liquid in flowing from the interface location to the outlets is small compared to the large-centrifugally-induced head from the rotating liquids.
The liquid outlets are typically.open scoops of the type shown in Figs. 2, 3,=4, and S.
In Fig: 2 a rotary separator is show-n at 110 and having an annular portion 111 with a surface llla facing radially inwardly toward the separator axis 112 of rotation (the same as axis 19b in Fig. 1). A liquid film or layer builds up-as a-ring 113 on the rotating surface and is shown to have a thickness "t". Such liquid may typically be supplied in a jet, as from a two-phase nozzle. The nozzle, jet'and separator elements are schematically shown in Fig. 5. See also U.S. P atent 5,385,446, incorporated herein by reference, and wherein the momentum of the jet is transferred to the separator at its inner surface llla, inducing.rotation.
A scoop or diffuser structure is provided at 114 for removing liquid in the ring 113. The scoop has an entrance 115 defined by radially separated inner and outer lips 115a and 115b presented toward the relatively ~-' CA 02305407 2000-03-30 ,' .
oncoming liquid in the ring. Lip 115b is immersed"In the liquid ring; and lip 115a is located radially inwardly of the inner surface 113a of the liquid ring. Ring liquid at 113b, radially inwardly of the scoop lip 115b, enters the scoop at 113c, and flows via a passage 116 in the scoop toward outlet 117. The scoop is normally non-rotating, i.e., fixed, or it may rotate, but at a slower rate than the separator.
Gas that has separated from the liquid that builds up as layer 113 collects in the separator interior, as at 118. Since lip 115a lies inwardly of the liquid ring inner surface 113a, there is a tendency for separated gas to enter the scoop at region 120, due to the drag effect of the rotating liquid ring upon the gas adjacent the liquid surface 113a.
Barrier structure is provided, and located proximate the scoop entrance or inlet, to block gas exiting to the scoop. one such barrier structure is indicated at 121, and as having a-barr-ier surface 121a projecting radially outwardly of the scoop inner lip 115b, i.e., toward the liquid ring, whereby liquid on the ring travels relatively past barrier surface 121a to enter the scoop at its inlet. The barrier surface has a doctor tip extent, indicated at 121b, controlling the radial thickness at t2 of the liquid ring that enters the scoop. In this regard, tz is normally less than tl. The doctor tip extent 121b is also normally of a width (parallel to axis 112) about the same as that of the scoop inlet.
The barrier surface is shown to have taper in ~~.
I
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,~. CA 02305407 2000-03-30 ' .; ,9 , .", ,". ,='= ''~.- , ; ; ; ; : ; ;
the direction of relative travel of liquid that enters the scoop, and that taper is preferably convex, to minimize or prevent build up of liquid in a turbulent wake at the scoop entrance. Note in Fig. 3 that the scoop inlet width w is of lesser extent than the liquid in the ring, i.e., ring liquid exists at widthwise opposite sides of the scoop, as at 113e and 113f.
Accordingly, separated gas is prevented, or substantially prevented, from entering the scoop to flow to the outlet, and an efficient gas-liquid separation is achieved.
Another aspect concerns the provision of means for effecting controllable displacement of the barrier structure toward the liquid ring, whereby the thickness t2 of the liquid layer entering the scoop is controlled.
In the Fig. 2 and Fig. 3 example, such barrier displacement control means is shown in the form of a spring 125, positioned to urge the barrier structure toward the liquid ring. A balance is achieved between the force of the spring acting to urge the barrier toward the liquid ring, and the force of liquid impinging on the convex surface 121a of the barrier, to position the barrier radially as a function of separator rotary speed, liquid ring. rotary speed, and liquid viscosity, whereby a controlled rate of liquid ingestion into the scoop to match liquid supply to the ring is achieved, and without air ingestion, i.e., the inlet is left open to liquid inflow, but is blocked for gas.
Guide structure is also provided for guiding such displacement of the barrier structure as it moves in r.4 ~~4M
. , . . ,,. , , . ,. . ,,. ,.
direction toward and away from the liquid ring. See for example engaged relatively sliding surfaces 129 and 130 of the barrier and scoop stem 131, attached to the scoop and sliding in the bore in a sleeve 129a attached to the scoop. A stop 134 on the stem is engageable with the end 133a of the sleeve to limit radially outward movement of the barrier structure, and its doctor tip, as referred to.
Figs. 4 and 5 show use of a foil 40 or foils immersed in the liquid and angled relative to the direction of liquid ring travel, to receive liquid impingement acting to produce a_force component in a radially outward (away from axis 12) direction. That foil is connected to the barrier structure 121, as via struts.42, to exert force on the barrier acting to move it into or toward the liquid. Such force countered by the force exerted on the barrier convex surface, as referred to above, and a balance is achieved, as referred to. No spring is used in this example.
The advantage of these types of outlets for the three-phase separator are that large changes in liquid flow rate can be accommodated with only small changes in liquid height. This enables large changes in oil flow or water flow to be swallowed by the outlet without large increases in the pressure drop or location of the oil-water interface 7.
Another form of outlet is shown in Fig. 6. An open outlet passage 50 is placed at the location of the desired radially inwardly facing oil level 51. The oil flows into the passage and forms a gas-oil interface 43 51, at the location where the jet flow 45, from a liquid (oil) nozzle 44, which is produced by the centrifugally-induced head from that interface location, equals the incoming oil flow. Nozzle 44 is spaced radially outwardly from outlet passage 50, and connected thereto by a duct 54 (an open weir), which rotates with the rotor. The nozzle opening is preferably sized for the maximum possible oil flow.
Flows less than that maximum cause the interface 43 to move more radially outward, reducing the head, and hence flow from the nozzle.
A similar arrangement is shown for the water outlet 52. The principles are the same as described for the oil outlet. See water radially inwardly facing level 62, gas-water interface 63, flow 65 from liquid (water) nozzle 64, and duct 70 (an open weir).
The provision of these outlets enables additional power to be generated from the reaction forces of the water and oil jets emanating from the associated nozzles. The outlet flows can be collected in volutes similar to that previously shown in Fig. 1 a.
Either type of outlet can be used for either liquid, independently of the type of outlet chosen for the other liquid.
it is a major object of the invention to provide a simple, effective method and appa.ratus meeting the above needs.
According to the present invention, there is provided a method of operating a rotating separator apparatus, to which fluid including gas and liquid is supplied in a fluid jet as via a nozzle , the method comprising the steps of providing at said apparatus an outlet for flowing li(juid A of higher density, and providing at said apparatus an outlet for flowing liquid B of lesser density, said liquids A and B having a stable interface location determined by the relative locations of said outlets, providing at least one of said outlets in the form of a scoop immersed in at least one of said liquids collecting as a centrifugally-induced liquidous ring travelling relative to the scoop, and further a) separating the liquids from the gas in said stream, at a first zone within said rotating apparatus, b) separating the liquids into liquids of differing density at a second zone within said apparatus, c) said separating including providing a scoop immersed in at least one of said liquids traveling relative to the scoop, the method being characterised by the further step of d) providing a movable inlet barrier in association with the scoop to block entry of gas into the scoop.
According to the present invention, there is also provided a rotating separator apparatus comprising means as a nozzle to supply a fluid including gas and liquid to the separator, the separator further comprising an outlet for flowing liquid A of higher density, and an outiet for flowing liquid B of lesser density, said liquids A and B having a stable interface location determined by the relative locations of said outlets, at least one of said outlets having the form of a scoop immersed in at least one of said liquids collecting as a centrifugally-2a induced liquidous ring travelling relative to the scoop, the apparatus further camprising a) means for separating the liquids from the gas in said stream, at a first zone within said rotating apparatus, b) means for separating the liquids into liquids of differing density at a second zone within said apparatus, c) means for said separating including a scoop immersed in at least one of said liquids travelling relative to the scoop, and being characterized by d) a movable inlet barrier in association with the scoop to block entry of gas into the scoop.
it is another object to provide method and apparatus to achieve complete separation of- gas, oil, water, and solids. It operates either by the two-phase' fluid energy or by a supplementary motor drive. It has a self-regulating featuze to handle widely varying ratios of gas, oil and water with no externa:L controls.
A further olaject concerns removal from the fluid jet of entrained solid parti.cles, the method including providing a solids removal passage in" the rotating-separator apparatus, and including separating i . , i J . . , = , . . .
t . 1'= . a r . ' ' i ' . t i ' , t '.
~the particles which are separated. by transfer to the passage.
Yet another object includes provision at the rotating separator apparatus of a passage for receiving a liquid A of higher density, providing at the apparatus an outlet for liquid A, and providing at the apparatus an outlet for liquid B of lesser density, the liquids A and B having a stable interface location determined by the relative locations of the outlets and passage, such that substantially complete separation of flowing liquids A
and B occurs for a relatively wide range of flows. At least one of the outlets may advantageously be in the form of a scoop immersed in at least one of the liquids flowing as in a liquidous ring relative to the scoop. A
movatie barrier may be provided in association k ith the scoop to block entry of gas into the scoop.
An additional object includes supporting the barrier for movement in response to changes in force applied to the barrier by at least one of the liquids flowing relative to the scoop.
A still further object includes providing one or more of the outlets at the rotating separator apparatus to have the form of an open weir, and flowing liquid via that weir to a passage leading to a liquid nozzle, as will be described.
Finally, it is an object of the invention to provide for liquid leaving the nozzle in the form of a jet producing thrust, and including transferring the thrust to the rotating separator apparatus.
ey These and other objects and advantages of the . ~..a-..-' . .. . ..õ.tito .. __"x . . -. ....
...:. .. '~ " . ..! F.. - .,s::: .. -Y . V.e-:'.3r...u - . .. ..., . n.._ __..
.. ... ..
invention, as well as the details of an illustrative embodiment, will be more fully understood from the following specification and drawings, in which:
DRAWING DESCRIPTION
Fig. 1 is a sectional view, i.e., an axial radial plane, of three-phase rotary apparatus incorporating the invention;
Fig. 1 a is a view like Fig. 1;
Fig. 2 is a fragmentary section showing details of a scoop having an entrained immersed in a rotating ring of liquids, and taken in a plane normal to the axis of separator rotation;
Fig. 3 is a fragmentary section taken on lines 3-3 of Fig. 2;
Fig. 4 is a view like Fig. 2 showing a modification;
Fig. 5 is a view taken on lines 5-5 of Fig. 4; and Fig. 6 is a fragmentary section showing an open weir outlet to a liquid nozzle.
DETAILED DESCRIPTION
Fig. 1 shows a version of the three-phase rotary separator structure 32. A mixture of oil, gas and water is expanded in nozzle 17. The resulting gas and liquid jet 1 is well collimated. The jet impinges generally tangentially onto a moving (rotating) surface 2. As shown in U.S. Patent 5,385,446, the surface is solid with holes 3, to permit drainage of the liquids and solids. Surface 2 is defined by the inner side of a rotating separator annulus 2a connected as by rotor 8 and structure 31 to a rotating shaft 19 of structure 32. Shaft bearings are shown at=
locations l3a. The moving surface may alternatively be comprised of the separated liquid, in which case no solid surface 2 is required. -The centrifugal force field acting on the gas and liquid jet, when it impacts the moving surface, causes an immediate radially inward separation of the gas from the liguids. The separated gas flows through gas blades 3 in the Yotor 8, transferring power to the rotor and shaft 19. The gas leaves through an exit port 18.
Blades 9 are.spaced about the rotor axis 19b.
The oil and water, and any particulate solids, flow into the. space between the outer wall 20 and the separating surface 2, in the, centrifugal force field.
The grea-ter density of water causes it to acquire a radial outwar-d velocity and separate from the oil f low 4.
Separated water is indicated at S. The separating oil and water flow axially through slots at location 3a in the rotor, toward the oil outlet 10, and toward the water outlet 13, respectively.
If the tangential velocity of the gas and liquid jet 1 impinging on the separating surface 2 i s greater than the rotating surface speed, the liquids wi.3_l..
be slowed by frictional forces transferring power to the PC'I'/N097/00267 . . E'' . . . Q . , , < < . , , . .
separating surface and hence to the rotor and shaft. Zf the tangential velocity of the jet is lower than the desired rotating surface speed, external power must be transferred to the shaft, and hence rotor and separating surface, to drag the slower liquids up to the speed of the rotating surface. The power can be transferred, for example by a motor, or by the shaft of another rotary separator.
The solids, being heavier than the water, are thrown to the inner side of the wall 20. The solids are collected at the farthest radial position 6 of that wall, and flow at 21 with a small amount of water into a volute 22 from which they are discharged.
A barrier 12 to the balance of the water and cll- flow-ng --g'tGFardlV_.,_..: s tile water to flow through structure-defined passages 23 located below (outwardly of ) the water-oil interface 7, formed by the centrifugal force field.
The relative placement of the oil outlet 10 in the oil collection zone 10a, and the water outlet 13, in the water collection zone 13a beyond barrier 12 causes the oil-water interface 7a to form at a location radially outward of both the oil outlet and the water outlet, but which is radially inward from the water passages 23.
This location of the rotating interface at 7a effects separation of the oil and water. Note that interface 7a intersects barrier 12, and that 2ones 10a and 13a are at opposite axial sides of barrier 12. The interface radial location is determined by the following relation, listing dimensions as shown in Fig. 1a:
C~ .
~}d ~~ '-4vnra~ua?4cImCIm~TM ..=-. '_ . .-, . . . . . . , h_ . .: . , - ",rr.... ..._, . -.._...._...._.--. ns..rrrs-"~'~~~.~... tF. _ poW ( r2s - r2o )= P~,m ( r't2_r2~ ) where p, = oil density põ = water density m = rpm of surface 2 ri = radius to oil - water interface r, = radius to oil outlet rõ = radius to water outlet The interface location is independent of the relative amounts of water and oil, so long as the pressure drop of liquid in flowing from the interface location to the outlets is small compared to the large-centrifugally-induced head from the rotating liquids.
The liquid outlets are typically.open scoops of the type shown in Figs. 2, 3,=4, and S.
In Fig: 2 a rotary separator is show-n at 110 and having an annular portion 111 with a surface llla facing radially inwardly toward the separator axis 112 of rotation (the same as axis 19b in Fig. 1). A liquid film or layer builds up-as a-ring 113 on the rotating surface and is shown to have a thickness "t". Such liquid may typically be supplied in a jet, as from a two-phase nozzle. The nozzle, jet'and separator elements are schematically shown in Fig. 5. See also U.S. P atent 5,385,446, incorporated herein by reference, and wherein the momentum of the jet is transferred to the separator at its inner surface llla, inducing.rotation.
A scoop or diffuser structure is provided at 114 for removing liquid in the ring 113. The scoop has an entrance 115 defined by radially separated inner and outer lips 115a and 115b presented toward the relatively ~-' CA 02305407 2000-03-30 ,' .
oncoming liquid in the ring. Lip 115b is immersed"In the liquid ring; and lip 115a is located radially inwardly of the inner surface 113a of the liquid ring. Ring liquid at 113b, radially inwardly of the scoop lip 115b, enters the scoop at 113c, and flows via a passage 116 in the scoop toward outlet 117. The scoop is normally non-rotating, i.e., fixed, or it may rotate, but at a slower rate than the separator.
Gas that has separated from the liquid that builds up as layer 113 collects in the separator interior, as at 118. Since lip 115a lies inwardly of the liquid ring inner surface 113a, there is a tendency for separated gas to enter the scoop at region 120, due to the drag effect of the rotating liquid ring upon the gas adjacent the liquid surface 113a.
Barrier structure is provided, and located proximate the scoop entrance or inlet, to block gas exiting to the scoop. one such barrier structure is indicated at 121, and as having a-barr-ier surface 121a projecting radially outwardly of the scoop inner lip 115b, i.e., toward the liquid ring, whereby liquid on the ring travels relatively past barrier surface 121a to enter the scoop at its inlet. The barrier surface has a doctor tip extent, indicated at 121b, controlling the radial thickness at t2 of the liquid ring that enters the scoop. In this regard, tz is normally less than tl. The doctor tip extent 121b is also normally of a width (parallel to axis 112) about the same as that of the scoop inlet.
The barrier surface is shown to have taper in ~~.
I
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,~. CA 02305407 2000-03-30 ' .; ,9 , .", ,". ,='= ''~.- , ; ; ; ; : ; ;
the direction of relative travel of liquid that enters the scoop, and that taper is preferably convex, to minimize or prevent build up of liquid in a turbulent wake at the scoop entrance. Note in Fig. 3 that the scoop inlet width w is of lesser extent than the liquid in the ring, i.e., ring liquid exists at widthwise opposite sides of the scoop, as at 113e and 113f.
Accordingly, separated gas is prevented, or substantially prevented, from entering the scoop to flow to the outlet, and an efficient gas-liquid separation is achieved.
Another aspect concerns the provision of means for effecting controllable displacement of the barrier structure toward the liquid ring, whereby the thickness t2 of the liquid layer entering the scoop is controlled.
In the Fig. 2 and Fig. 3 example, such barrier displacement control means is shown in the form of a spring 125, positioned to urge the barrier structure toward the liquid ring. A balance is achieved between the force of the spring acting to urge the barrier toward the liquid ring, and the force of liquid impinging on the convex surface 121a of the barrier, to position the barrier radially as a function of separator rotary speed, liquid ring. rotary speed, and liquid viscosity, whereby a controlled rate of liquid ingestion into the scoop to match liquid supply to the ring is achieved, and without air ingestion, i.e., the inlet is left open to liquid inflow, but is blocked for gas.
Guide structure is also provided for guiding such displacement of the barrier structure as it moves in r.4 ~~4M
. , . . ,,. , , . ,. . ,,. ,.
direction toward and away from the liquid ring. See for example engaged relatively sliding surfaces 129 and 130 of the barrier and scoop stem 131, attached to the scoop and sliding in the bore in a sleeve 129a attached to the scoop. A stop 134 on the stem is engageable with the end 133a of the sleeve to limit radially outward movement of the barrier structure, and its doctor tip, as referred to.
Figs. 4 and 5 show use of a foil 40 or foils immersed in the liquid and angled relative to the direction of liquid ring travel, to receive liquid impingement acting to produce a_force component in a radially outward (away from axis 12) direction. That foil is connected to the barrier structure 121, as via struts.42, to exert force on the barrier acting to move it into or toward the liquid. Such force countered by the force exerted on the barrier convex surface, as referred to above, and a balance is achieved, as referred to. No spring is used in this example.
The advantage of these types of outlets for the three-phase separator are that large changes in liquid flow rate can be accommodated with only small changes in liquid height. This enables large changes in oil flow or water flow to be swallowed by the outlet without large increases in the pressure drop or location of the oil-water interface 7.
Another form of outlet is shown in Fig. 6. An open outlet passage 50 is placed at the location of the desired radially inwardly facing oil level 51. The oil flows into the passage and forms a gas-oil interface 43 51, at the location where the jet flow 45, from a liquid (oil) nozzle 44, which is produced by the centrifugally-induced head from that interface location, equals the incoming oil flow. Nozzle 44 is spaced radially outwardly from outlet passage 50, and connected thereto by a duct 54 (an open weir), which rotates with the rotor. The nozzle opening is preferably sized for the maximum possible oil flow.
Flows less than that maximum cause the interface 43 to move more radially outward, reducing the head, and hence flow from the nozzle.
A similar arrangement is shown for the water outlet 52. The principles are the same as described for the oil outlet. See water radially inwardly facing level 62, gas-water interface 63, flow 65 from liquid (water) nozzle 64, and duct 70 (an open weir).
The provision of these outlets enables additional power to be generated from the reaction forces of the water and oil jets emanating from the associated nozzles. The outlet flows can be collected in volutes similar to that previously shown in Fig. 1 a.
Either type of outlet can be used for either liquid, independently of the type of outlet chosen for the other liquid.
Claims (25)
1. A method of operating a rotating separator apparatus (32, 110), to which fluid including gas and liquid is supplied in a fluid jet (1) as via a nozzle (17), the method comprising the steps of providing at said apparatus an outlet (13) for flowing liquid A of higher density, and providing at said apparatus an outlet (10) for flowing liquid B of lesser density, said liquids A and B having a stable interface location (7a) determined by the relative locations of said outlets (10, 13), providing at least one of said outlets (10, 13) in the form of a scoop (114) immersed in at least one of said liquids collecting as a centrifugally-induced liquidous ring (113) travelling relative to the scoop (114), and further a) separating the liquids from the gas in said stream, at a first zone within said rotating apparatus (32, 110), b) separating the liquids into liquids of differing density at a second zone within said apparatus (32, 110), c) said separating including providing a scoop (114) immersed in at least one of said liquids traveling relative to the scoop (114), the method being characterised by the further step of d) providing a movable inlet barrier (121) in association with the scoop (114) to block entry of gas into the scoop (114).
2. The method of claim 1 wherein the fluid jet (1) has momentum, and including transferring energy from the jet (1) to said rotating apparatus (32, 110).
3. The method of claim 1 including transferring power from an external source to said rotating apparatus (32, 110).
4. The method of claim 1 wherein the fluid jet contains solid particles, and including providing a solids removal passage (22) in the rotating apparatus (32, 110), and including conducting the particles (21) which are separated by centrifugal force to said passage (22).
5. The method of claim 1 which includes providing each of said outlets (10, 13) in the form of a scoop immersed (114) in the liquid flowing to said outlet (10, 13) and collecting as a centrifugally-induced liquidous ring (113) travelling relative to the scoop (114).
6. The method of claim 1 which includes providing at least one of said outlets (10, 13) in the form of an open weir (54, 70).
7. The method of claim 6 which includes flowing liquid via said weir (54, 70) to a passage (50, 52) leading to a liquid nozzle (44, 64).
8. The method of claim 1 including supporting the barrier (121) for movement in response to changes in force applied to the barrier (121) by at least one of said liquids flowing relative to the scoop (114).
9. The method of claim 7 wherein liquid leaves the nozzle (44, 64) in the form of a jet-producing thrust (45, 65), and including transferring said thrust (45, 65) to said rotating separator apparatus (32, 110).
10. The method of claim 1 wherein blades (9) are provided in association with said rotating operation apparatus (32, 110) and including flowing the separated gas to the blades (9) to produce power transferred to the rotating apparatus (32, 110).
11. The method of claim 2 including providing a rotating annular surface (2) at which the liquids are separated- from the gas.
12. The method of claim 11 wherein said surface (2) is provided by providing a separator annulus (2a) that is ported to pass liquids centrifugally away from gas.
13. The method of claim 11 wherein said surface (2) is provided by separated liquids collecting centrifugally in a rotating ring.
14. The method of claim 1 which includes providing rotating barrier structure (12) between said outlets (10, 13), and passage means (23) for water to flow from one axial side of the barrier structure (12) to the opposite axial side of the barrier structure (12) toward said water outlet (13), the oil collecting at said one side of the barrier structure (12), and the water collecting at the opposite side of said barrier structure (12).
15. The method of claim 1 including producing water and oil pressure heads in water and oil flow via said nozzles (64, 44), and discharging water and oil in jets (65, 45) pressurized by said heads, for producing thrust transferred to said apparatus (32, 110).
16. Rotating separator apparatus (32, 110) comprising means as a nozzle to supply a fluid including gas and liquid to the separator, the separator further comprising an outlet (13) for flowing liquid A of higher density, and an outlet (10) for flowing liquid B of lesser density, said liquids A and B having a stable interface location (7a) determined by the relative locations of said outlets (10, 13), at least one of said outlets (10, 13) having the form of a scoop (114) immersed in at least one of said liquids collecting as a centrifugally-induced liquidous ring (113) travelling relative to the scoop (114), the apparatus further comprising a) means for separating the liquids from the gas in said stream, at a first zone within said rotating apparatus (32, 110), b) means for separating the liquids into liquids of differing density at a second zone within said apparatus (32, 110), c) means for said separating including a scoop (114) immersed in at least one of said liquids travelling relative to the scoop (114), and being characterized by d) a movable inlet barrier (121) in association with the scoop (114) to block entry of gas into the scoop (114).
17. The apparatus of claim 16 wherein the fluid jet (1) has momentum, and including means for transferring energy from the jet (1) to said rotating apparatus (32, 110).
18. The apparatus of claim 16 including means for transferring power from an external source to said rotating apparatus (32, 110).
19. The apparatus of claim 16 wherein the fluid jet contains solid particles, and including a solids removal passage (22) in the rotating apparatus (32, 110), and including means for conducting the particles (21) which are separated by centrifugal force to said passage (22).
20. The apparatus of claim 16 which includes each of said outlets (10, 13) having the form of a scoop (114) immersed in the liquid flowing to said outlet (10, 13) and collecting as a centrifugally-induced liquidous ring (113) travelling relative to the scoop (114).
21. The apparatus of claim 16 which includes at least one of said outlets (10, 13) being in the form of an open weir (54, 70).
22. The apparatus of claim 21 which includes means flowing liquid via said weir (54, 70) to a passage (50, 52) leading to a liquid nozzle (44, 64).
23. The apparatus of claim 16 including means supporting the barrier (121) for movement in response to changes in force applied to the barrier (121) by at least one of said liquids flowing relative to the scoop (114).
24. The apparatus of claim 22 wherein liquid leaves the nozzle (44, 64) in the form of a jet-producing thrust (45, 65) and including means transferring said thrust (45, 65) to said rotating separator apparatus (32, 110).
25. The apparatus of claim 16 wherein blades (9) are provided in association with said rotating operation apparatus (32, 110), and including means flowing the separated gas to the blades (9) to provide power transferred to the rotating apparatus (32, 110).
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| PCT/NO1997/000267 WO1999017884A1 (en) | 1996-05-30 | 1997-10-03 | Three-phase rotary separator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2305407A1 CA2305407A1 (en) | 1999-04-15 |
| CA2305407C true CA2305407C (en) | 2007-05-29 |
Family
ID=19907849
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002305407A Expired - Fee Related CA2305407C (en) | 1997-10-03 | 1997-10-03 | Three-phase rotary separator |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU739662B2 (en) |
| CA (1) | CA2305407C (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4087261A (en) * | 1976-08-30 | 1978-05-02 | Biphase Engines, Inc. | Multi-phase separator |
-
1997
- 1997-10-03 CA CA002305407A patent/CA2305407C/en not_active Expired - Fee Related
- 1997-10-03 AU AU46384/97A patent/AU739662B2/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| AU4638497A (en) | 1999-04-27 |
| CA2305407A1 (en) | 1999-04-15 |
| AU739662B2 (en) | 2001-10-18 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20171003 |