GB2250328A

GB2250328A - Apparatus for dividing a stream of multi-phase fluid

Info

Publication number: GB2250328A
Application number: GB9125033A
Authority: GB
Inventors: Michael Hales
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1990-11-28
Filing date: 1991-11-26
Publication date: 1992-06-03
Also published as: NO914633L; NO914633D0; GB9025829D0; GB9125033D0

Abstract

An apparatus for dividing a stream of multi-phase fluid to form a plurality of streams is provided. The apparatus comprises a vessel provided with an inlet conduit and a plurality of dividing chambers arranged in the vessel, each dividing chamber having an inlet opening at or near said inlet conduit and being in fluid communication with the inlet conduit via said inlet opening. A plurality of outlet conduits are provided, each outlet conduit extending from the vessel and being in fluid communication with one of said dividing chambers. <IMAGE>

Description

APPARATUS FOR DIVIDING A STREAM OF MULTI-PHASE FLUID The invention relates to an apparatus for dividing a stream of multi-phase fluid to form a plurality of streams. Division of a stream of multi-phase fluid is for example required when in an offshore operation oil and gas are simultaneously transported through a pipeline network having branch connections. When the stream of oil and gas passes such a branch connection the stream is divided to form a plurality of streams, each stream of the plurality of streams being routed through a pipeline branch. In such conditions the problem may occur that the streams in the pipeline branches have unequal fractions of oil and unequal fractions of gas. The problem may even be more pronounced when slug flow occurs, whereby alternating batches of liquid and gas flow through the network.

An apparatus for dividing a stream of multi-phase fluid in a plurality of streams is proposed in US patent No. 4 505 297 disclosing a vessel provided with an inlet conduit and a plurality of outlet conduits. When a stream of multi-phase fluid in the form of a mixture of liquid and gas enters the known vessel via the inlet conduit, the flowrate of the mixture decreases in the vessel because of the larger internal diameter of the vessel compared to the inlet conduit, which may result in a separation of the phases and a non-uniform distribution of the liquid and the gas in the vessel. Such non-uniform distribution leads to different fractions of liquid and different fractions of gas in the streams discharged through the outlet conduits.

It is an object of the invention to provide an apparatus for dividing a stream of multi-phase fluid in a plurality of streams having substantially equal fractions of each phase.

The object is achieved by providing an apparatus for dividing a stream of multi-phase fluid to form a plurality of streams, comprising a vessel provided with an inlet conduit, a plurality of dividing chambers arranged in the vessel, each dividing chamber having an inlet opening at or near said inlet conduit and being in fluid communication with the inlet conduit via said inlet opening, and a plurality of outlet conduits, each outlet conduit extending from the vessel and being in fluid communication with one of said dividing chambers. When a stream of multi-phase fluid flows through the inlet conduit, the fluid enters the dividing chambers via the inlet openings thereof before the flowrate of the fluid decreases in the vessel and thus before separation of the phases can occur.

Thus, in each dividing chamber a stream of fluid is formed, the streams in the dividing chambers having substantially equal fractions of each phase. The fluid in each dividing chambers is discharged therefrom through the outlet conduit in communication with the dividing chamber.

In a suitable embodiment of the apparatus according to the invention the vessel has an outer wall formed as a body of revolution around a central longitudinal axis, and the inlet conduit is coaxially arranged at an end of the vessel.

In order that the stream of multi-phase fluid is smoothly divided in a plurality of streams the dividing chambers are suitably defined by a plurality of longitudinal dividing walls arranged in the vessel, each dividing wall extending radially from near the central longitudinal axis of the vessel to the outer wall thereof.

Suitably, each dividing wall extends longitudinally from near the inlet conduit to a flat plate arranged perpendicular to the central longitudinal axis and opposite to said inlet conduit.

The amount of fluid entering the individual dividing chambers can be made adjustable by providing the vessel with means for adjusting the angular position of each dividing wall relative to the outer wall of the vessel, because the inlet areas of the inlet openings are dependent on the mutual angular positions of the dividing walls.

The angular position of each dividing wall relative to the outer is suitably made adjustable when the dividing walls are adjustably attached to a rod extending in the vessel along the central longitudinal axis thereof so as to allow adjustment of said angular position of the dividing wall.

The invention will now be discussed in more detail with reference to the accompanying drawings, in which Fig. 1 shows schematically a longitudinal side view of an embodiment of the apparatus according to the invention; Fig. 2 shows schematically cross-section 2-2 of Fig. 1; and Fig. 3 shows schematically cross-section 3-3 of Fig. 2.

In Figs. 1-3 is shown a vessel 1 having an outer wall 3 with a cylindrical lower part 5 and a frusto-conical upper part 7, and a dome-shaped end wall 9 arranged opposite to the frusto-conical upper part 7 of the outer wall 3. A coaxial inlet conduit 11 is in fluid communication with the interior of the vessel 1 at the frusto-conical upper part 7 of the outer wall 3. The inlet conduit 11 has a section 13 of reduced diameter connected to the frusto-conical upper part 7 of the outer wall 3. A flat plate 15 extends in the vessel 1 near the dome-shaped end wall 9 and perpendicular to a central longitudinal axis 17 of the vessel 1.

A cylindrical rod 19 extends in the vessel 1 along the central longitudinal axis 17 thereof, which rod 19 is at one end 21 welded to the dome-shaped end wall 9 and supported at its other end byradial struts 23 extending from the rod 19 to the inner surface of the coaxial inlet 11. Three upper hubs 25, 27, 29 are tightly but rotatably arranged around an upper section 30 of reduced diameter of the rod 19, and three lower hubs 31, 33, 35 are tightly but rotatably arranged around a lower section 36 of reduced diameter of the rod 19. Three longitudinal dividing walls in the form of a first dividing wall 38, a second dividing wall 40 and a third dividing wall 42 are arranged in the vessel 1, each dividing wall 38, 40, 42 being fixedly attached to one of the upper hubs 25, 27, 29 and one of the lower hubs 31, 33, 35.Each dividing wall 38, 40, 42 extends longitudinally from the flat plate 15 into the inlet conduit 11 and radially from the rod 19 to the inner surface of the outer wall 3, the dividing walls 38, 40, 42 being arranged at equal mutual angular spacings. However, the mutual angular spacings of the dividing walls 38, 40, 42 can be adjusted by rotating the dividing walls 38, 40, 42 around the rod 19.

A first dividing chamber 44 is defined between the flat plate 15, the outer wall 3, the first dividing wall 38 and the second dividing wall 40. A second dividing chamber 46 is defined between the flat plate 15, the outer wall 3, the second dividing wall 40 and the third dividing wall 42. A third dividing chamber 48 is defined between the flat plate 15, the outer wall 3, the third dividing wall 42 and the first dividing wall 38. Each dividing chamber 44, 46, 48 has an inlet opening (not shown) in the form of an open upper end of the chamber 44, 46, 48. Each dividing chamber 44, 46, 48 is provided with an outlet conduit 50, 52, 54 extending through the outer wall 3, whereby each outlet conduit 50, 52, 54 has a protruding section 56, 58, 60 which protrudes into the dividing chamber 44, 46, 48.

During normal use of the apparatus shown in Figs. 1-3 a stream of multi-phase fluid of a fraction liquid and a fraction gas is supplied from the inlet conduit 11 to the vessel 1. When the fluid enters the section 13 of reduced diameter of the inlet conduit 11 the flow accelerates and the fluid is mixed due to the abrupt reduction in diameter. Mixing of the fluid in the inlet conduit 11 ensures that the liquid and the gas are uniformly distributed over the cross-section of the inlet conduit 11 as the fluid arrives at the upper ends of the dividing walls 38, 40, 42 and enters the dividing chambers 44, 46, 48. Thus, three streams of fluid (not shown) are formed, one in each dividing chamber 44, 46, 48. The three streams have equal fractions of liquid and equal fractions of gas because of the uniform distribution of the fluid over the cross-section of the inlet conduit as the fluid enters the dividing chambers 44, 46, 48. The fluid of each stream is discharged through the outlet conduits 50, 52, 54. Liquid which flows in a dividing chamber 44, 46, 48 along the inner surface of the outer wall 3 is prevented from flowing directly into the outlet conduit 50, 52, 54 which extends into said dividing chamber 44, 46, 48 because the outlet conduit 50, 52, 54 protrudes into the dividing chamber 44, 46, 48. Such liquid can only enter the outlet conduit 50, 52, 54 after mixing with the fluid in the dividing chamber 44, 46, 48, so that it is prevented that liquid flows into the outlet conduit 50, 52, 56 separately from the mixture. Thus, it is achieved that the fluid of the streams discharged through said outlet conduits 50, 52, 54 forms a homogeneous mixture of multi-phase fluid, the three streams having equal fractions of liquid and equal fractions of gas.

Various modifications of the present invention will become apparent to those skilled in the art from the foregoing description and drawings. Such modifications are intended to fall within the scope of the appended claims.

Claims

1. Apparatus for dividing a stream of multi-phase fluid to form a plurality of streams, comprising a vessel provided with an inlet conduit, a plurality of dividing chambers arranged in the vessel, each dividing chamber having an inlet opening at or near said inlet conduit and being in fluid communication with the inlet conduit via said inlet opening, and a plurality of outlet conduits, each outlet conduit extending from the vessel and being in fluid communication with one of said dividing chambers.

2. The apparatus of claim 1, wherein the vessel has an outer wall formed as a body of revolution around a central longitudinal axis, and wherein the inlet conduit is coaxially arranged at an end of the vessel.

3. The apparatus of claim 2, wherein said dividing chambers are defined by a plurality of longitudinal dividing walls arranged in the vessel, each dividing wall extending radially from near the central longitudinal axis of the vessel to the outer wall thereof.

4. The apparatus of claim 3, wherein each dividing wall extends longitudinally from near the inlet conduit to a flat plate arranged perpendicular to the central longitudinal axis and opposite to said inlet conduit.

5. The apparatus of claim 3 or 4, wherein the vessel is provided with means for adjusting the angular position of each dividing wall relative to the outer wall of the vessel.

6. The apparatus of claim 5, wherein said dividing walls are adjustably attached to a rod extending in the vessel along the central longitudinal axis thereof so as to allow adjustment of said angular position of each dividing wall.

7. The apparatus of any one of claims 1-6, wherein each outlet conduit has a protruding section which protrudes into the dividing chamber the outlet conduit is in communication with.

8. The apparatus of any one of claims 1-7, wherein the inlet conduit has a section of reduced diameter arranged near the housing.

9. The apparatus of any one of claims 2-8, wherein the longitudinal axis of the vessel extends substantially in vertical direction.

10. The apparatus of claim 9, wherein the stream of multi-phase fluid comprises substantially liquid and gas, and wherein the coaxial inlet conduit is connected to the upper end of the vessel.

11. The apparatus substantially as described hereinbefore with reference to the drawings.