MXPA00003256A - Three-phase rotary separator - Google Patents

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

ROTARY SEPARATOR OF THREE PHASES DESCRIPTION OF THE INVENTION The invention relates generally to the separation of three phases of fluid-gas, oil and water and more particularly has to do with achieving such separation using a rotating separating apparatus. In addition, the invention relates to methods of operating the rotating separator apparatus in relation to the spoon means immersed in a liquid ring on the rotary separator. The solids that entered the flow must also be separated. In existing non-rotating methods, a dense gravity separation tank is required to be used, and only partial separation of the oil and water phases is achieved. Therefore, additional treatment is required to separate those constituents. Secondary treatment methods require the consumption of large amounts of energy, for example by means of speed centrifugal machines. Another advantage is the size and weight of the containers required. For submarine oil and gas production, large container separation requires large, expensive structures to support its weight. From US-A-4 087 261 it is known from a rotary separating apparatus that shows spoons fully immersed in the apparatus to remove the separated liquids. As shown, the flow velocity of a fully submerged spoon is set by the speed of the liquid and the entrance area of the spoon. The increase in flow velocity would cause the liquid to enter a particular submerged spoon to flood it and go to another spoon. The decrease in flow velocity would cause the spoon to take additional liquid from another area. There is a need for improved means to efficiently achieve the separation of the three phases - gas, oil and water; further, there is a need to achieve such separation in a mixture of such fluids passing through a nozzle, as in a jet stream.

BRIEF DESCRIPTION OF THE INVENTION It is a main object of the invention to provide a simple, effective method and an apparatus that meets the above needs.

Basically, the above object is fulfilled by operating the rotary separating apparatus to which fluid, including gas and liquid (such as oil and water mixed together) are supplied in a fluid jet, by means of a nozzle, the steps of the basic method they include: a) separating the liquids from the gas in the stream, in a first zone within the rotary apparatus. b) separating the liquid into liquids of different density in a second zone within the apparatus, characterized by c) such separation includes providing a spoon submerged in at least one of the liquids traveling in relation to the spoon. As will be apparent, the fluid jet has a momentum which is used to transfer energy from the jet to the rotating separator apparatus. The energy can be transferred from an external source to the rotary separator. It is another object to provide method and apparatus to complete the separation of gas, oil, water and solids. It is operated either by the two-phase fluid energy or by an additional motor actuator. This has a self-regulating characteristic to widely handle various proportions of gas, oil and water without external controls. A further object relates to the removal of the fluid jet from solid particles entering, the method includes providing a solids removal passage in the rotating separator apparatus, and includes separating the particles that were separated by transfer to the passage. Still another object includes the provision in the rotary separating apparatus of a passage for receiving a very high density liquid A, providing in the apparatus an outlet for the liquid B of lower density, liquids A and B having a stable interface location determined by the relative locations of departures and passages, so that the 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 spoon submerged in at least one of the liquids flowing as in a ring of liquids in relation to the spoon. A movable barrier of entry can be provided in association with the bucket to block the entry of gas into the bucket. A further object includes supporting the barrier to move in response to changes in forces applied to the barrier by at least one of the liquids flowing in relation to the bucket. Yet a further object includes providing one or more of the outlets in the rotary separator apparatus to have the shape of an open dam, and fluid fluid through that dam to a passage leading to the liquid nozzle as will be described. Finally, it is an object of the invention to provide for the liquid exiting the nozzle in the form of a pulse that produces a jet and including transferring the pulse to the rotary separator apparatus. These and other objects and advantages of the invention as well as the details of an illustrative embodiment will be fully understood from the following specification and drawings, in which: DESCRIPTION OF THE DRAWINGS Figure 1 is a sectional view, that is, an axial radial plane, of three phases of the rotary apparatus embodying the invention; Figure la_ is a view similar to the Figure 1; Figure 2 is a fragmentary section showing the details of a spoon having a submersed drag in a rotating liquid ring, and which captures a plane normal to the axes of the rotation of the separator; Figure 3 is a fragmentary section taken from lines 3-3 of Figure 2; Figure 4 is a view similar to Figure 2 showing a modification; Figure 5 is a view taken on lines 5-5 of Figure 4; and Figure 6 is a fragmentary section showing an open dam outlet to a liquid nozzle.

DETAILED DESCRIPTION Figure 1 shows a version of the structure 32 of the three-phase rotary separator. A mixture of oil, gas and water expands in a nozzle 17. The resulting gas and the jet of liquid 1 is well collimated. The jet strikes generally and tangentially on a surface 2 that moves (rotates). See in this regard the description in U.S. Patent 5 385 446, incorporated herein by reference. In this case shown, the surface is solid with holes 3 to allow drainage of liquids and solids. The surface 2 is defined by the lateral entrance of a rotary separating ring 2a connected by a rotor 8 and structure 31 to a rotary arrow 19 of structure 32. The bearings of the arrow are shown in the locations 19a_. The surface movement can alternatively be compressed from the separated liquid, and in which case the non-solid surface 2 is required. The centrifugal force fields act on the gas and liquid jet, when it impacts the moving surface, it causes an immediate radially inward separation of the gas from the liquids. The gas flow separated through the gas blades 9 in the rotor 8, which transfer energy to the rotor and arrow 19. The gas exits through an exit port 18. The blades 9 are spaced around the rotor shaft 19b_. The oil and water, and any solid particles, flow into the space between the outer wall 20, and the separated surface 2, in the centrifugal force field. The greater density of the water causes it to acquire a radial outward speed and separated from the flow 4 of oil. The separated water is indicated at 5. The separation of the oil and the water flows axially through the slots at the location 8a in the rotor, towards the oil outlet 10 and towards the water outlet 13, respectively. If the tangential velocity of the gas and the jet of liquid 1 impacting on the separation surface 2 is greater than the surface velocity of rotation, the liquids will be of 1 st degree due to the frictional forces that transfer energy to the surface. of separation and consequently to the rotor and to the arrow. If the tangential velocity of the jet is less than the desired rotational surface velocity, the external energy must be transferred to the arrow, and consequently the rotor and the separation surface, drag the slower liquids up to the speed of the rotation surface . The energy can be transferred, for example by means of a motor, or by the arrow of the other rotary separator. The solids, which are heavier than water, are thrown to the inner side of the wall 20. The solids are collected in the radial position 6 furthest from the wall, and the flow in 21 with a small amount of water towards a volute 22 from which it is downloaded. A barrier 12 for the rest of the water and oil flowing to the right forces the water to flow through passages 23 of defined structure located below (out of) the interphase 7 of water / water 1, formed through the centrifugal force field. The relative placement of oil outlet 10 and zone 10a_ of oil collection and water outlet 13, in the water collecting area 13a beyond the barrier 12 causes the interface 7a of the water pipe to form in a location radially outward of both, the oil outlet and the water outlet, although which is radially inward of water passage 23. This location of the rotating interface in 7a effects the separation of oil and water. Note that the interface 7 a_ intersects the barrier 12, and that the zone 10a and 13a are on axially opposite sides of the barrier 12. The location of the radial interface is determined by the following relationship, the dimensions are listed as shown in FIG. Figure the: P o? (r: 1-r20) = P "? (r2x-r2w) where Po = oil density Pw = water density? = rpm of the surface 2 r _ = radius for the water-oil interface ro = radius for the oil outlet rw = radius for the water outlet. The location of the interface is independent of the relative amounts of water and oil, with the proviso that the liquid pressure drop in the current from the interface location to the output is smaller compared to the large centrifugally induced head. from the rotation liquids. The liquid outlets are typically open spoons of the type shown in Figures 2, 3, 4 and 5.

In Figure 2, a rotary separator is shown at 110 and has an annular portion 111 with a llla_ facing surface radially inward from the spacer shaft 112 (like the same axle 19b_ in Figure 1). A film or liquid layer constructed as a ring 113 on the surface of rotation and is shown to have a thickness Such liquid can typically be supplied in a jet, such as from a two-phase nozzle. The nozzle, the jet and the separating elements are schematically shown in Figure 5. See also U.S. Patent 5 385 446, incorporated herein by reference, and wherein the momentum of the jet is transferred to the separator at its internal llla_ surface, inducing rotation. A spoon or diffuser structure is provided at 114 for removing liquid in ring 113. The ladle has an inlet 115 defined by radially spaced outer and inner edges 115a_ and 115b_ presented to the relatively incoming liquid in the ring. The edge 115b_ is immersed in the liquid ring; and the flange 115a_ is located radially inward of the inner surface 113a_ of the liquid ring. The liquid of the ring 113b_, radially inward of the flange 115b, introduces the ladle into 113c_, and flows through a passage 116 in the ladle towards the outlet 117. The ladle is normally not rotary ie it is fixed, or it can rotate, but at a slower speed than the separator. The gas that has been separated from the liquid that is constructed as a layer 113 collected in the interior separator, as in 118. Since the edges 115a_ rest inward from the interior surface 113a_ of the liquid ring, there is a tendency to separate the gas to introduce the spoon in the region 120, due to the slow advancing effect of the liquid ring rotating in the gas adjacent the surface 113a of the liquid. The barrier structure is provided, and is located near the entrance or access of the bucket, to block the existing gas in the bucket. One such barrier structure is indicated at 121, and when it has a barrier surface 121a projecting radially outwardly from the inner edge of the bucket 115b, that is, towards the liquid ring, where the liquid on the ring travels relatively passing barrier surface 121 a_ to introduce the spoon inside. The barrier surface has a doctor tip extension, indicated at 121b_, which controls the radial thickness at t 2 of the liquid ring that the spoon introduces. In this regard, t2 is usually less than you. The doctor tip extension 121b is also usually of an amplitude (parallel to the axis 112) approximately the same as that of the inner spoon. The barrier surface is shown to have a conical junction in the direction of relative travel of the liquid entering the ladle, and that the conical junction is preferably convex, to minimize or prevent the construction of the liquid in a turbulent eddy wake at the inlet of the spoon. Note in Figure 3 that the internal amplitude w of the bucket is smaller than the liquid in the ring, that is, the liquid in the ring comes out on opposite sides in the direction of the bucket's amplitude, as in 113e_ and 113f_ . Accordingly, the separated gas is prevented or substantially prevented, from entering the ladle to flow to the outlet, and a gas-liquid separation is achieved.

Another aspect that has to do with the provision of means for effecting the controllable displacement of the barrier structure towards the liquid ring whereby the thickness t2 of the layer of liquid entering the ladle is controlled. In the example of Figure 2 and Figure 3, such barrier displacement control means are shown in the form of a spring 125, positioned to push the barrier structure toward the liquid ring. A balance is achieved between the force of the spring acting to push the barrier towards the liquid ring, and the force of the liquid striking the convex surface 121a_ of the barrier, to place the barrier radially as a function of the rotary speed of the separator, the rotational speed of the liquid ring, and the liquid viscosity, whereby a controlled speed of liquid intake within the bucket to balance the liquid supply, and without ingestion of air, that is, the interior is left open for liquid intake, but is blocked for the gas. The guide structure is also provided to guide such displacement of the barrier structure as it moves in the direction towards and away from the liquid ring. See for example 'the relatively coupled sliding surface 129 and 130 of the barrier and the bucket rod 131, attached to the bucket and slid into the hole in a sleeve 129a_ attached to the bucket. A detent 134 on the rod is capable of engaging the edge 133a_ of the sleeve to radially limit the outward movement of the barrier structure, and its doctor tip, as referred to. Figures 4 and 5 show the use of a hydrophobic fin or hydrophobic fins submerged in the liquid and angled in relation to the direction of travel of the liquid ring, to receive the shock of liquid acting to produce a force component in a liquid. direction radially outward (away from axis 12). This hydrophobic fin is connected to the barrier structure 121, as by means of struts 42, to exert force on the barrier acting to move them into or into the liquid. Such a force is disturbed by the force exerted on the convex barrier surface, as referred to in the foregoing, and a balance was achieved, as he referred to. In this example, springs are not used.

The advantages for this type of output for the three-phase separators are that large changes in the liquid flow velocity can be accommodated with only small changes in the liquid height. This allows large changes in oil flows or water flows to be swallowed by the outlet without large increases in drip pressure or location of oil-water interface 7. Another form of output is shown in Figure 6. An exit passage opening 50 is placed at the location of the desired level of oil 51 facing radially inwardly. The oil flows into the passage and forms a gas-oil interface 43 in the location where the jet flow 45, from a liquid (petroleum) in the nozzle 44 that is introduced by the centrifugally induced head from the interface location, equal to the oil flow input. The nozzles 44 are spaced radially outwardly from the exit passage 50, and connected thereto by a duct 54 (an open dam), which rotates with the rotor. The nozzle opening is preferably sized for the maximum possible oil flow. The smaller flows than those maximums cause the interface 43 to move radially outwards, and consequently flow from the nozzle. A similar arrangement is shown for water outlet 52. The principles are the same as described for the oil output. See level 62 facing radially inward of the water, gas-water interface 63, flow 65 from the liquid (water) of nozzle 64, and duct 70 (a dam opening). The provision of these outputs allows additional energy to be generated from the reaction forces of the water and oil jets emanating from the associated nozzles. The outflows can be collected in volutes similar to those previously shown in Figure la. Any type of outlet can be used for any liquid, regardless of the type of outlet chosen by the other liquid.

Claims (31)

1. In the method for operating the rotating separator apparatus, to which fluid, including gas and liquid is supplied in a fluid jet as by means of a nozzle, the steps include a) separating the liquid from the gas in the stream, in a first zone within the rotating apparatus, and b) separating the liquids in liquids of different density in a second zone within the apparatus. characterized by c) the separation includes providing a spoon submerged in at least one of the liquids traveling in relation to the spoon.

2. The method of claim 1 wherein the fluid jet has a momentum, and includes transferring energy from the jet to the rotating apparatus.

3. The method of claim 1 which includes transferring energy from an external source to the rotating apparatus.

4. The method of claim 1 wherein the fluid jet contains solid particles, and includes providing a passage for removal of solids in the rotating apparatus, and includes driving the particles which are separated by centrifugal force to the passage.

5. The method of claim 1, which includes providing in the apparatus an outlet for liquid A flowing from the greater density, and providing in the apparatus an outlet for liquid B flowing from the lower density, liquids A and B having a stable interface location determined by the relative location of the outputs.

6. The method of claim 5, which includes providing at least one of the outlets in the form of a spoon submerged in at least one of the liquids that collect as a centrifugally-induced liquid ring traveling in relation to the spoon.

7. The method of claim 5 which includes providing each of the outlets in the form of a spoon submerged in the liquid flowing to the outlet and collecting as a ring of centrifugally induced liquid traveling in relation to the spoon.

8. The method of claim 5, which includes providing at least one of the exits in the form of an open dam.

9. The method of claim 8, which includes liquid flowing through the dam to a passage leading to a liquid nozzle.

10. The method of claim 6, which includes providing a movable internal barrier in association with the bucket to block the entry of gas into the bucket.

11. The method of claim 10, which includes supporting the barrier for movement in response to the change in force applied to the barrier by at least one of the liquids flowing in relation to the bucket.

12. The method of claim 9, wherein the liquid exits the nozzle in the form of a pulse that produces a jet, and which includes transferring the pulse to the rotating separator apparatus.

13. The method of claim 1, wherein the blades are provided in association with the rotary operating apparatus and includes flowing the separated gas to the blades to produce energy transferred to the rotating apparatus.

14. The method of claim 2, which includes providing a rotating annular surface in which the liquids are separated from the gas.

15. The method of claim 14, wherein the surface is provided by the provision of a separator ring that is cut to pass liquids centrifugally away from the gas.

16. The method of claim 14, wherein the surface is provided by separating the centrifugally collected liquids in a rotating ring.

17. The method of claim 5, which includes providing a rotary barrier structure between the outlets, and the passage means for water to flow from an axial side of the barrier structure to the opposite axial side of the barrier structure toward the outlet of water, oil collected on one side of the barrier structure, and water collected on the opposite side of the barrier structure.

18. The method of claim 5, which includes producing water and oil pressure heads in the flow of water and oil by means of nozzles, and discharging water and oil in pressurized jets through the heads, to produce impulse transferred to the apparatus.

19. In the rotating separator apparatus, to which fluid includes gas, the liquid is supplied in a fluid jet by means of a nozzle, the combination including a) means for separating the liquids from the gas in the stream, in a first zone within the rotary apparatus, and b) means for separating liquids in liquids of different density in a second zone within the apparatus, characterized by c) means for separation including a spoon submerged in at least one of the liquids traveling in relation to the spoon .

20. A combination of claim 19, wherein the fluid jet has momentum, and includes means for transferring energy from the jet to the rotating apparatus.

21. A combination of claim 19, including means for transferring energy from an external source to the rotating apparatus.

22. A combination of claim 19, wherein the fluid jet contains solid particles, and includes a solids removal passage in the rotating apparatus, and includes means for driving the particles which are separated by centrifugal force to the passage.

23. The combination of claim 19, which includes means for providing in the apparatus an outlet for liquid A flowing from the greater density, and an outlet for liquid B flowing from the lower density, liquids A and B have a location of stable interphase determined by the relative location of the outputs.

24. A combination of claim 20, including at least one of the outlets having the shape of a spoon submerged in at least one of the liquids collected as a ring of centrifugally induced liquids traveling in relation to the spoon.

25. Combination of the rei indication 23, which includes each of the outlets that has the shape of a spoon immersed in the liquid that flows to the outlet and collected as a ring of centrifugally induced liquid traveling in relation to the spoon.

26. A combination of claim 23, including at least one of the exits that is in the shape of an open dam.

27. A combination of claim 26, which includes liquid means flowing through the dam to a passage leading to a liquid nozzle.

28. Combination of claim 24, which includes an internal barrier movable in association with the bucket to block the entry of gas into the bucket.

29. A combination of claim 28, including means for supporting the barrier for movement in response to changes in force applied to the barrier by at least one of the liquids flowing in relation to the bucket.

30. The combination of claim 27, wherein the liquid exits the nozzle in the form of a pulse that produces a jet, and means including transferring the pulse to the rotating separator apparatus.

31. A combination of claim 19, wherein the blades are provided in association with the rotary operating apparatus, and include means for flowing the separated gas to the blades to provide energy transferred to the rotating apparatus.