EP0299966A1

EP0299966A1 - Apparatus for separating mixtures

Info

Publication number: EP0299966A1
Application number: EP87902326A
Authority: EP
Inventors: Shui-Yin Lo; Noel Carroll
Original assignee: Conoco Specialty Products Inc
Current assignee: Lubrizol Specialty Products Inc
Priority date: 1986-04-07
Filing date: 1987-04-06
Publication date: 1989-01-25
Also published as: JPH01502407A; KR880701135A; GB2209691A; GB8823327D0; SE8803546D0; WO1987006159A1; GB2209691B; EP0299966A4; SE8803546L

Abstract

Un appareil centrifuge, servant à séparer des mélanges liquides multiphases de composants ayant des densités différentes, se caractérise par des organes d'entraînement (24, 54) destinés à faire tourner un élément creux allongé (5, 12) présentant une extrémité d'admission et une extrémité de sortie ainsi qu'un axe central (X-X), par un organe d'admission (30) pour l'admission du mélange liquide dans l'élément creux et par des organes de sortie (40, 38) pour l'écoulement vers l'extérieur de courants séparés d'au moins deux composants du mélange liquide. L'élément creux rotatif (5, 12) engage de façon hermétique l'organe d'admission (30) et les organes de sortie (40, 38) et, dans un mode de réalisation, comporte un élément spiraloïde ou hélicoïdal (7) fixé à la paroi interne de l'élément rotatif (5, 12) en vue de sa rotation avec ledit élément et, dans un autre mode de réalisation, comprend une première et une seconde sections d'extrémité creuses (32, 44), l'une comportant une ou plusieurs entrées d'alimentation (17, 36) et l'autre étant pourvue de conduits d'évacuation (46, 48, 51, 52, 15).A centrifugal device for separating multi-phase liquid mixtures from components of different densities is characterized by drive members (24, 54) for rotating an elongated hollow member (5, 12) having an inlet end and an outlet end as well as a central axis (XX), by an inlet member (30) for the admission of the liquid mixture into the hollow element and by outlet members (40, 38) for the outward flow of separate streams of at least two components of the liquid mixture. The rotary hollow element (5, 12) hermetically engages the inlet member (30) and the outlet members (40, 38) and, in one embodiment, comprises a spiraloid or helical member (7) attached to the inner wall of the rotary member (5, 12) for rotation with said member and, in another embodiment, includes first and second hollow end sections (32, 44), l 'one comprising one or more supply inlets (17, 36) and the other being provided with discharge ducts (46, 48, 51, 52, 15).

Description

"APPARATUS FOR SEPARATING MIXTURES" This invention relates generally to apparatus for separating mixtures of the type containing liquids, solids and/or gases and more particularly, though not exclusively, to the separation of multi-phase fluids, such as, for example, oil, water and/or gas.

According to the present invention there is provided apparatus for separating multi-phase mixtures comprising an elongate hollow member having an inlet end and an outlet end and a central axis, inlet means for inlet of liquid mixture to be separated to the member at a location at the inlet end of the member and outlet means for outflow of separated streams of at least two components of the liquid mixture, being of different densities, and means for rotating said member to effect the separation of the components of the mixture when admitted via said inlet means, for said outflow via said outlet means. Preferably, the inlet means comprises a hollow head section with one or more feed inlets extending to the open interior thereof , said head section including an open end, the inlet end of said member -2- being sealingly and rotatingly engaged within the open end of the head section whereby, in use, liquid mixture fed to the inlet means passes via the or each said feed inlet into the open interior of the head section and thence into the said hollow member via the open end of said head section and via an adjacent portion, such as via an open end, of the rotatable member.

In one arrangement, the or each said feed inlet may be arranged substantially tangentially to the central axis of the hollow member. In other arrangements the feed inlet is arranged substantially co-axially with the central axis of the hollow member. In the latter arrangement, the mixture to be separated is fed into the hollow member axially with respect thereto. Means may be provided to assist in generating the rotational velocity of the mixture in addition to the rotating hollow member.

Preferably the outlet means comprises a second hollow head section sealingly and rotatably engaged with the said other end of said rotatable hollow member and into the interior of which, in use, components of said mixture pass from said member, such as via an open end thereof,said second head section being provided with at least one take-off duct open to the interior of the second head section and positioned to remove one of the separated streams. The second head section may include a further one or more take-off ducts positioned to remove another of the separated streams. In another arrangement the outlet means may comprise one or more outlets arranged substantially tangentially to the central axis of the member for receiving the more dense separated stream and a co-axial outlet or outlets for removing the less dense separated stream of the mixture. Preferably the co-axial outlets are disposed at the outlet end of said member although in some instances the co-axial outlets may be disposed at the inlet end.

In a preferred embodiment the member includes therein a generally spiral or helix like separator element having a central axis co-axial with that of the hollow member the separator element being at least partially disposed within the hollow member for rotation therewith about the central axis. An axial passage or zone may be disposed in the region of the central axis extending between the inlet and outlet of the hollow member. In one preferred form the hollow member comprises a tapered hollow member with the larger end preferably forming the inlet, and the smaller end forming the outlet.

Preferred embodiments of the invention will hereinafter be described with reference to the accompanying drawings in which:

Figure 1 is a schematic side elevation of one form of apparatus according to the invention; Figure 2 is a schematic view of a part of another form of apparatus according to the invention; Figure 3 is a schematic sectional view of apparatus which includes the part shown in Figure 2; Figure 4 is a schematic layout of a system incorporating apparatus according to the invention; and

Figure 5 is a schematic view of apparatus according to a further embodiment of the invention. Referring to Figure 1 of the drawings, the apparatus 10 comprises a hollow rotatable member 12 which is in the form of an elongate hollow cylinder having an inlet end 13 and an outlet end 19. The hollow member 12 is mounted in be.aring 14, for rotation about its central axis X-X. A drive means comprising an electric motor 54 operatively connected to member 12 via belt 55 for causing rotation of the member 12. The apparatus further includes an inlet means 30 at one end thereof comprising a hollow structure 32 having an open end which communicates with hollow member 12. An inlet duct 36 in this case is in the form of a tangentially feed pipe which opens into the structure 32. An appropriate seal is provided between the structure 32 and the hollow member 12. An outlet 38 is provided in the structure 32 which operates in a manner which will be hereinafter described. _* Outlet means 40 provided at the other end of the hollow member 12, this outlet means comprising structure 44 having an open end facing into the hollow member 12. This is similar in structure to the inlet means and includes a tangentially outlet duct 51 and an axial outlet duct 52.

Baffles (not shown) may be provided on the interior of the hollow member 12 to assist in generating the flow of the mixture as it passes through the hollow member. These baffles may be in the form of circumferentially spaced longitudinally extending ribs. Ref rring specifically to Figures 2 and 3, the apparatus generally indicated at 1 comprises a rotatable hollow member 5 in the form of a hollow cylinder having a central axis X-X with an inlet end and an outlet end. A generally spiral or helix like separator element 7 is at least partially disposed within the member 5 for rotation therewith about the central axis. An axis passage or zone in the region of the central axis X-X extends between the inlet and outlet ends of the hollow member.

The arrangement is such that in use a multi-phase mixture for separation can enter the hollow member through the feed inlet 17 and is separated at least partially into separate phases with the less dense phase forming a central core in the axial passage or zone and the more dense phase being urged radially outwardly therefrom. The separated phases under the action of the rotating generator and hollow member can be delivered towards the outlet of the cavity where they can be discharged and collected in any suitable manner.

As shown in one form, the elongated member is of substantially constant cross-section. In another form, the elongated member comprises a tapered hollow element with the larger end preferably forming the inlet, and the smaller end forming the outlet. The tapered portion may have curved or straight walls or a combination of both. Furthermore, it may include parallel sided sections as well.

Preferably, the hollow member is mounted for rotation about the longitudinal axis between the open ends. The separator element 7 as shown in the form of a spiral or helical member which is secured at its outer peripheral edge to the inner surface of the hollow member 5. Where the hollow member 5 is of constant cross-sectional cylindrical form as shown, the separator element spiral is also of constant cross-sectional outer dimension, whereas in the case of the tapered main body, the spiral or helical element is configured to follow the taper of that of the body portion. Preferably the spiral of helical member comprises a ribbon-like flat strip which winds around its central axis and in spaced relation thereto so that the space between its inner peripheral edge and the central axis define the axial passage or zone referred to above. A central collecting tube 4, is disposed within the axial passage and extends partially along the length of the element.

*The apparatus a's shown further includes an outer housing 3 with the hollow member 5 being disposed therein for rotation relative thereto the feed inlet 17 being in housing 3. Take-off ports 15 and 16 are provided for receiving the phases separated during the passage of the mixture through the hollow member. The hollow member may be mounted for rotation relative to the housing by means of suitable bearings and seals may be provided at each end of the main body to provide a seal between its inlet and outlet ends. Drive means may be provided for rotating the main body. The drive means may comprise a motor operatively supported by the housing for rotating the main body relative thereto. Suitable transmission means, such as gearing or the like may provide for the rotation of the two members relative to one another. Any suitable form of drive means may be used such as an air motor, electric motor or the like.

The apparatus of the present invention may be used in a system which may comprise a plurality of such apparatus arranged in series for selectively separating the various phases from one another. In this regard reference can be had to Figure 4.

Material to be separated is fed into the apparatus through inlet 15 and is caused to at least partially separate owing to the rotation of the hollow member 5. It is to be appreciated that inlet 15 can be of the same diameter as body portion 6. The lightest phase of the mixture tends to concentrate in the core or passage 19 and can be collected at outlet 16. The heavier phase is caused to move towards the outer part of the generator and can be collected at outlet 17.

One example of a system for separating mixtures of oil/water/gas using apparatus according to the invention is shown in Figure 4. In this system, the mixture to be separated is delivered through a choke 20 to a first apparatus according to the invention 21. Gas is discharged through line

22 and a detector 25 monitors the amount of oil being discharged with the gas. The oil/water mixture is fed through line 27 to a second apparatus

23 according to the invention where the oil and water are further separated from one another.

A gas detector 29 monitors the quality of gas entering the second apparatus 25. The separated water is passed through a cyclone separator 37 which may be of the type described by applicant in several of its co-pending applications. A pump 35 transfers the separated oil back to the second apparatus 25.

The apparatus 10 shown in Figure 5 of the drawings is similar to that of Figure 1 and comprises a hollow rotatable member 12 which may, for example, be in the form of an elongate hollow cylinder of constant diameter, or of diameter which varies from place to place .along the length thereof, such as being tapered.

The member 12 is mounted in bearing 14, for rotation about an axis X-X. As shown, this rotation is effected by drive means 22 comprising an electric motor 24 and co-operating gears 26, 28 coaxially mounted, respectively, on the member 12 and on the output shaft of the motor 24. The apparatus 10 further includes, at one end of the member 12, an inlet means 30 comprising a hollow structure 32 in this case being formed of a hollow cylinder structure 32 closed at one end by an end wall 34 and having an open opposite end into which one open end of the member 12 extends. The structure 32 has an inlet duct 36 in this case in the form of a tangential feed pipe which opens into the structure 32 at a location towards the closed end thereof. The open end of the member 12, where it extends into the open end of the inlet structure 32, is provided with seal means (not shown) which is effective to peripherally seal an annular gap between the outer surface of the member 12 and the inner surface of the open end of the structure 32 into which the member 12 extends, whilst permitting free rotation of the member 12 -relative to structure 32.

At the opposite end of the member 12, the separator 10 is provided with outlet means 40. This is shown as comprising an elongate hollow outlet structure 44. Structure 44 includes a hollow generally tapered member 44a of circular cross-section which extends into an adjacent open end of the member 12. Seal means (not shown) is provided for sealing the annular gap between the periphery of the outer surface of the member 44a, where it extends into the member 12, and the inner surface of the open end of the member 12 at that location.

At the end of the structure 33 furtherest away from member 12, the member 44a opens to an outlet duct 46 for take-off of one component of the liquid to be separated in the separator. Duct 46 may comprise an extension of the member 44a. A second outlet duct 48 is also provided, this being in the form of a tube which extends into the duct 46 and is open to the duct 46 centrally thereof, leaving a space of annular form between the periphery of this tube and the interior surface of the duct 46.

The sealing means provided between outlet structure 40 and the member 12, is so arranged as to permit free rotation of the member 12 whilst still maintaining a fluid tight seal between the ember 12 and the outlet structure. Since the sealing means between inlet structure 32 and the member 12 is also so characterized, the structures 32 and 40 may be stationary, notwithstanding that the member 12 in use is rotated.

To use the apparatus, liquid mixture to be separated is passed into the inlet means 30 via the duct 32, and thence passes within the internal cylindrical interior of the inlet structure 32, with a helical motion around the common axis of the structure 32 and the member 12. Thence, the liquid to be separated passes into the member 12 undergoes a helical motion about axis X-X and travels lengthwise along member 12, whilst being to centrifugal action whereby at the end of the member 12 nearest structure 44, the more dense of the constituent components of the mixture are thrown outwardly to occupy a layer of annular form around the internal periphery of the member 12, whilst the less dense components occupy a central core close to the axis X-X of the member 12. The so separated components are then passed axially through the member 44, the more dense components passing directly out the duct 46 whilst the less dense components are passed out the duct 48 which, as explained previously, is open at a location positioned centrally about the axis 20.

The described apparatus has been found to be very satisfactory for separating oil-water mixtures in which case the oil emerges from duct 48 and the water emerges at duct 46. Although member 44a is shown as being tapered, it may be of any other form such as parallel sided cylindrical.

Claims

CLAIMS :

1. Apparatus for separating multi-phase mixtures characterized by an elongate hollow member (5,

12) having an inlet end and an outlet end and a central axis (X-X), inlet means (30) for inlet of liquid mixture to be separated to the hollow member (5, 12) at a location at the inlet end of the hollow member and outlet means (40, 38) for outflow of separated streams of at least two components of the liquid mixture, being of different densities, and means (24, 54) for rotating said hollow member (5, 12) to effect the separation of the components of the mixture when admitted via said inlet means, for said outflow via said outlet means.

2. Apparatus according to claim 1 wherein said inlet means (30) comprises a hollow head section (32) with one or more feed inlets (17, 36) extending to the open interior thereof, said head section

(32) including an open end, the inlet end of said hollow member (5, 12) being sealingly and rotatingly engaged within the open end of the head section (32) whereby , in use, liquid mixture fed to the inlet means passes via the or each said feed inlet into the open interior of the head section and thence into the said hollow member via the open end of said head section.

3. Apparatus according to claim 2 wherein said outlet means (40) comprises a second hollow head section (44) sealingly and rotatably engaged with the outlet end of said rotatable member and into the interior of which, in use components of said mixture pass from said member, such as via an open end thereof, of said second head section being provided with take-off ducts (46, 48, 51, 52, 15) open to the interior of the second head section and positioned to remove the separated streams.

4. Apparatus according to claim 1 or claim 2 wherein said outlet means comprises one or more outlets (51) arranged substantially tangentially to the axis of the member for receiving the dense mixture and a co-axial outlet or outlets (52,

38) for removing the less dense phase of the mixture.

5. Apparatus according to claim 4 wherein said co-axial outlets (52) are disposed at said outlet end of said member.

6. Apparatus according to anyone of claims 1 to 5 wherein said member includes a generally spiral or helix like separator elements (4) having its axis co-axial with the central axis, the separator element being at least partially disposed within the hollow member for rotation therewith the body about the central axis, there being an axial passage or zone in the region of the central axis extending between the inlet and outlet of the hollow member (5).

7. Apparatus according to any preceding claim wherein said hollow member comprises a tapered hollow member with the larger end preferably forming the inlet, and the smaller end forming the outlet.