Fluid inlet device for use in gas liquid separators

Abstract

The present invention provides a fluid inlet device (1) for a separator, comprising a lower part (2) and an upper part (3), wherein the lower part (2) comprises an inner wall surface (4) having a horizontal cross-section comprising a circular arc, a top section (5) comprising a fluid outlet (6), a bottom section (7) comprising a liquid outlet (8), and a tangential fluid inlet (9) for introduction of a fluid flow to the inner wall surface (4); the upper part (3) comprises multiple guiding vanes (10) arranged to guide a fluid flow, entering the upper part through the fluid outlet (6), in a horizontal direction away from the fluid outlet.

Claims

1. A fluid inlet device for a separator having an outer wall which comprises an inner surface that defines an interior of the separator, the fluid inlet device comprising: a lower part and an upper part which are configured to be positioned in the interior of the separator radially inwardly of the inner surface of the outer wall of the separator; wherein the lower part comprises an inner wall surface having a horizontal cross-section comprising a circular arc, a top section comprising a fluid outlet, a bottom section comprising a liquid outlet, and a tangential fluid inlet for introduction of a fluid flow to the inner wall surface; wherein the upper part comprises multiple guiding vanes arranged to guide a fluid flow entering the upper part through the fluid outlet in a horizontal direction away from the fluid outlet; and wherein the upper part comprises a top plate which extends radially over the multiple guiding vanes.

2. The fluid inlet device according to claim 1, wherein each of the multiple guiding vanes comprises a pocket arranged to capture a liquid film migrating along the guiding vane.

3. The fluid inlet device according to claim 2, wherein each of the multiple guiding vanes comprises a substantially vertical edge distal to the fluid outlet, and wherein the pocket is arranged at the vertical edge.

4. The fluid inlet device according to claim 1, wherein the top section of the lower part comprises a plate element in which the fluid outlet is arranged.

5. The fluid inlet device according to claim 4, wherein the plate element extends at least from a top edge of the inner wall surface to a circumference of the fluid outlet.

6. The fluid inlet device according to claim 4, wherein each of the guiding vanes is arranged on an upper surface of the plate element and extends from an inner circumference to an outer circumference of the plate element.

7. The fluid inlet device according to claim 1, further comprising a fluid obstruction vane arranged at the inner wall surface.

8. The fluid inlet device according to claim 1, wherein a cross-sectional area of the fluid outlet is larger than a cross-sectional area of the liquid outlet.

9. The fluid inlet device according to claim 1, wherein the guiding vanes are curved.

10. The fluid inlet device according to claim 1, further comprising a liquid protection plate arranged below the liquid outlet.

11. The fluid inlet device according to claim 6, wherein each guiding vane extends from an inner circumference of the plate element to beyond an outer circumference of the plate element.

12. The fluid inlet device according to claim 8, wherein a ratio of the cross-sectional area of the fluid outlet to the cross-sectional area of the liquid outlet is greater than 2.

13. The fluid inlet device according to claim 8, wherein a ratio of the cross-sectional area of the fluid outlet to the cross-sectional area of the liquid outlet is greater than 3.

Description

SHORT DESCRIPTION OF THE DRAWINGS

(1) The invention is described in detail by reference to the following drawings:

(2) FIG. 1 is a cross-sectional side view of a prior art scrubber featuring a vane inlet device.

(3) FIG. 2 is a cross-sectional side view of a prior art scrubber featuring a cyclonic inlet device.

(4) FIG. 3 is a cross-sectional side view of a scrubber featuring a fluid inlet device according to the invention.

(5) FIG. 4 is a transverse cross-sectional view of the fluid inlet device in FIG. 3.

(6) FIG. 5 is a transverse cross-sectional view of the fluid inlet device in FIG. 3.

(7) FIG. 6 is a perspective side view of the fluid inlet device in FIG. 3.

(8) FIG. 7 is a perspective top view of the fluid inlet device in FIG. 3.

(9) FIG. 8 is a transverse cross-sectional view of a further embodiment of a fluid inlet device according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(10) Two prior art fluid inlet devices are shown in FIGS. 1 and 2. Each of the fluid inlet devices is arranged in a scrubber vessel. The inlet device in FIG. 1 provides an initial gas/liquid separation by the use of vanes, while the inlet device in FIG. 2 provides an initial gas/liquid separation by use of an inlet cyclone (or hydrocyclone). As discussed above, both types of inlet devices have shortcomings regarding their ability to handle various flow regimes.

(11) The present invention provides a novel fluid inlet device as shown in FIGS. 3-7, which comprises a cyclonic separation section 2 (i.e. a lower part) for removal of bulk liquids by use of centrifugal force, in combination with a guiding vanes section 3 (i.e. an upper part) arranged above the cyclonic separation section to remove the remaining droplets from the gas stream.

(12) The fluid inlet device has been developed with the aim of: Minimizing the effect of unstable fluid flow conditions in the upstream piping of a gas/liquid separator, i.e. scrubber. Minimizing the destruction of any existing liquid film coming from the upstream piping of the separator. The cyclonic separation section provides an initial bulk separation of the incoming fluid flow, directing the bulk liquid toward the bottom of the cyclonic separation section and the gas phase in an upwards direction. Removing droplets from the gas phase exiting the cyclonic separation section. Due to the curved geometry of the guiding vanes, the droplets are directed towards the guiding vane walls where they coalesce, then the created coalesced liquid film/layer continues flowing towards the pockets where it is captured and drained in a downwards direction. Minimizing the amount of gas flow hitting the liquid surface at the bottom of the scrubber, in order to limit liquid re-entrainment. An anti-re-entrainment plate is installed below the drain pipe (i.e. the liquid outlet) to protect the liquid surface. Feeding the scrubber/separator symmetrically from the center as opposed from the side, while still obtaining a tangential direction of the inlet flow relative an inner wall surface of the cyclonic separation section. This is obtained by use of a tangential connecting box.

(13) The features of this device include the special design of pocketed guiding vanes 10 (see FIG. 5) in an upper part 3 of the device. Said vanes provide multiple tangential outlets 17 for the gas flow entering the upper part from the cyclonic separation section 2 of the device, while capturing a substantial amount of the droplets entrained in the gas flow. The tangential exit of the gas flow is also beneficial for improving the gas distribution in the upper section of a scrubber (i.e. gas/liquid separator), as well as to re-direct any droplets remaining in the gas flow towards the inner walls of the scrubber.

(14) A fluid inlet device 1 according to the present invention arranged in a scrubber is shown in FIG. 3. The fluid inlet device comprises a cyclonic separation section 2, wherein a bulk separation of a gas/liquid flow is performed by use of centrifugal force. The bulk separated liquid exits the cyclonic separation section 2 via a liquid outlet 8 in the bottom section of the lower part. An anti-re-entrainment plate 18 (or liquid protection plate) is arranged below the liquid outlet to limit the re-entrainment of droplets, from the liquid accumulated at the bottom of the vessel, into the gas phase.

(15) A cross-sectional view A-A of the cyclonic separation section 2 and the wall 19 of the scrubber is shown in FIG. 4. The cyclonic separation section 2 comprises a tangential inlet 9 for a fluid flow to be separated, a circular inner wall surface 4, a fluid obstruction vane 20 and the liquid outlet 8.

(16) The gas-liquid mixture (i.e. fluid flow to be separated) originates from an upstream piping into the fluid inlet device 1 of the scrubber. The flow is passed by means of a tangential connecting box (providing the tangential inlet 9) into the cyclonic separation section 2. Due to the applied centrifugal force, the bulk liquid of the fluid flow is separated from the major part of the gas phase and flows over the inner wall surface 4 of the cyclonic separation section. In this particular embodiment, the inner wall surface have a circular horizontal cross-section. However, embodiments wherein the inner wall surface have a horizontal cross-section comprising only a circular arc (i.e. not a full circular cross-section) is also contemplated. The circular arc may for instance extend from the tangential inlet to the fluid obstruction vane. The fluid obstruction vane 20 interrupts the flow of the bulk liquid, which is then drained out of the cyclonic separation section via the central bottom pipe 8 (i.e. a liquid outlet) arranged in a bottom section 7. In some embodiments, the fluid obstruction vane 20 may advantageously comprise a pocket and/or may have a curved shape, as described for the guiding vanes 10. The bulk liquid exits the liquid outlet at the bottom of the cyclone along with a minor part of the gas phase. In some embodiments, the liquid outlet may advantageously be arranged off-center, for instance below or in front of the fluid obstruction element. The anti-re-entrainment plate 18 is arranged below the liquid outlet 8 to avoid direct impact of the minor part of the gas phase on the liquid surface at the bottom of the scrubber.

(17) The major part of the gas phase and the remaining liquid droplets flow upwards at the center of the cyclonic separation section 2 and through the circular opening 6 (i.e. a fluid outlet) to the guiding vanes section 3 (i.e. the upper part) of the fluid inlet device, see FIGS. 5 and 7. For illustrative purposes, the plate element 15 in which the circular opening 6 is arranged is omitted from FIG. 5. The plate element is arranged between the cyclonic separation section 2 and the guiding vanes section 3, and prevents the bulk liquid flow along the inner wall surface of the cyclonic separation section from entering the guiding vanes section. In the guiding vanes section, the mixture of gas and liquid droplets exits the fluid inlet device in a tangential manner by passing multiple curved guiding vanes 10. Each of the multiple guiding vanes comprises a pocket 12 arranged on one end of the guiding vane to capture/trap most of the remaining droplets, which coalesce on the guiding vanes. In this particular embodiment, the pocket is arranged at the vertical edge 11, i.e. the edge of the guiding vane being distal to the circular opening 6. After capture, the coalesced droplets are drained in a downwards direction. The guiding vanes extend beyond the upper edge 16 of the cyclonic separation section, such that coalesced liquid is easily drained away from the fluid inlet device. Further, in this particular embodiment the guiding vanes section, see FIG. 6 comprises a top plate 13 having a hole 14 (i.e. center opening) in the center to reduce the gas recirculation above the fluid inlet device, as well as to improve the flow distribution in the upper section of the scrubber. The presence of the hole 14 is not an essential feature and it may be omitted depending on the specific application of the fluid inlet device.

(18) A topside perspective view of the fluid inlet device without the top plate 13 is shown in FIG. 7.

(19) A cross-sectional view of an alternative embodiment of the fluid inlet device is shown in FIG. 8. The view corresponds to the A-A section shown in FIG. 4. In this embodiment, the fluid obstruction vane 20 features a pocket 21 at the vane edge 22 and have a curved shape. Further, the liquid outlet 8 is positioned off center and in front of the fluid obstruction vane, i.e. in front of the vane surface facing a bulk liquid flow along the inner wall surface.