GB2503261A

GB2503261A - Inlet device

Info

Publication number: GB2503261A
Application number: GB201210970A
Authority: GB
Inventors: John Thomas Turner
Original assignee: ZETA PDM Ltd
Current assignee: ZETA PDM Ltd
Priority date: 2012-06-21
Filing date: 2012-06-21
Publication date: 2013-12-25
Also published as: GB201210970D0

Abstract

An inlet device 10, for use with a fluid separation vessel, comprises: a hollow body 11 provided with a plurality of inlets 12 and a plurality of corresponding outlets 13. Each inlet and its corresponding outlet is connected by a channel (14, Fig 5) through which a single-phase or multi-phase fluid may flow. Each channel has an inlet portion (15, Fig 5) and an outlet portion (16, Fig 5), the inlet portion extending in a first direction through the body and the outlet portion extending in a second direction through the body. The plurality of inlets is configured as a series of concentric apertures 17 centred about an axis which extends in the first direction and subdivided by at least one radial vane 18. The plurality of outlets is configured as a series of adjacent, at least partially annular apertures 19 centred about said axis and subdivided by the said at least one radial vane 18. The outermost inlet apertures 17b lead to the outlet apertures 19a closest to the plurality of inlets (the uppermost outlet apertures), and the innermost inlet apertures 17a lead to the outlet apertures 19b farthest from the plurality of inlets (the lowermost outlet apertures). Advantageously the device may be used with a vapour-liquid separation vessel and provides initial separation and de-foaming of bulk liquids from vapour from a multi-phase input fluid.

Description

Inlet Device The present invention relates to an inlet device for use with a fluid separation vessel, such as a vapour-liquid separation vessel, and especially, but not exclusively, for use with an oil-gas separation vessel.

A fluid separation vessel may be required to operate with single-phase fluid flow conditions, two-phase fluid flow conditions, or multi-phase fluid flow conditions. A two-phase separation vessel separates the two-phase input fluid into: (1) vapour (gas) and (2) total liquid; a three-phase separation vessel separates the three-phase input fluid into (1) vapour (gas), (2) a liquid oil phase and (3) a liquid aqueous phase. In all cases, any solids entrained in the input fluid may also be removable and, in all cases, density differentials between the components of the input fluid may be utilised in a gravity separation step.

A vapour-liquid separation vessel is a pressurised device used in several industrial applications to separate a vapour-liquid mixture into one or more of its constituent components. Industries and applications in which a vapour-liquid separation vessel may be employed include: oil refineries, natural-gas processing plants, petrochemical and chemical plants, refrigeration systems, air-conditioning systems, compressor systems, gas pipelines, geothermal power plants, combined cycle power plants and paper mills, to name but a few. Accordingly, a vapour-liquid separation vessel is typically provided with a fluid inlet, a vapour outlet, at least one liquid outlet and, optionally, a solids outlet or collection means, with the vessel itself otherwise being sealed to its external environment.

Transfer of a single-phase or multi-phase input fluid into a fluid separation vessel (via the fluid inlet provided) is usually achieved by means of a pipe, hose, channel or other such fluid communication means, which is connected to the vessel by means of an inlet device, typically by means of an appropriate seal. An inlet device should ensure correct operation of the separation vessel, enable an even flow distribution into and through the said vessel, thereby preventing channelling and maximising gravity separation, particularly of the initial bulk mixture, and enabling maximised separation of the fluid into its constituent components, thus increasing the throughput of the said vessel.

Many different types of inlet devices are known in the art, with varying designs depending on the intended application and/or the industry of use. For example, in the oil production industry, where separation vessels are used to separate oil-well fluids into oil, gas and water (and sand/solids where present), inlet baffles devices, half-open pipe devices, vane-type inlet devices and cyclonic inlet devices are all known, each having their own particular benefits and preferred circumstances of use.

An ill-designed and/or ill-chosen inlet device can, depending on the circumstances of its use, lead to a number of separation problems in the separation vessel to which said inlet device is fitted, including poor vapour and liquid distribution through a vapour-liquid separation vessel and an increased liquid content entrained in the vapour removed from the separation vessel. In an oil production separation vessel, a further separation problem that may arise is the occurrence of small water-in-oil (W/O) and oil-in-water (01W) emulsion droplets in each of the separated oil and water components, from which the internal phase is increasingly difficult to separate. This leads to contamination of the separated oil and water components.

When the input fluid to be separated is an oil-well multi-phase fluid, for example, the physical characteristics of the fluid itself may exacerbate any one or more of the problems described above. These deleterious characteristics include instability of the flow, and often include a swirling and/or rotational component, which is usually non-uniform and maldistributed across the diameter of the pipe (or the like) which feeds the flow to a separation vessel, and which may randomly split into discrete phase zones resulting in a type of hammer-action as it travels along the said pipe. This is known in the art as slugging".

Thus, despite the numerous different types of inlet device which are known and used in the art, there is a continuous need for improvement so as to minimise some, if not all, of the problems highlighted above. It is this need which the present inventor has sought to address.

Accordingly, a first aspect of the present invention provides an inlet device, for use with a fluid separation vessel, comprising: a hollow body provided with a plurality of inlets and a plurality of corresponding outlets, each inlet and its corresponding outlet being connected by a channel through which a single-phase or multi-phase fluid may flow, each channel having an inlet portion and an outlet portion, the inlet portion extending in a first direction through the body and the outlet portion extending in a second direction through the body, wherein the plurality of inlets is configured as a series of concentric apertures centred about an axis which extends in the first direction and subdivided by at least one radial vane, and wherein the plurality of outlets is configured as a series of adjacent, at least partially annular apertures centred about said axis and subdivided by the said at least one radial vane, whereby the outermost inlet apertures lead to the outlet apertures closest to the plurality of inlets (the uppermost outlet apertures), and the innermost inlet apertures lead to the outlet apertures farthest from the plurality of inlets (the lowermost outlet apertures).

For the avoidance of doubt, the terms uppermost" and "lowermost" define the relative locations of the series of outlet apertures in relation to the location of the plurality of inlets, and although these terms in particular refer to a preferred orientation of the inlet device when in use (as will be shown in more detail in the figures), they should be construed in accordance with the actual orientation of the device.

The inlet device of the present invention, when used with a fluid separation vessel, and especially a vapour-liquid separation vessel, enables the initial separation and de-foaming of bulk liquids from vapour from a multi-phase input fluid and the reduction of momentum of the output fluid so that the potential for droplet shatter, or bubble re-entrainment, is minimised. Furthermore, such use of the inlet device enables the reduction of re-entrainment of liquid into the vapour phase from the surface of the separated liquid or vapour re-entrainment into the liquid phase, and the reduction of turbulence and/or re-circulation in the liquid collection area of the vessel. It also transfers the inlet flow smoothly to the outlet, thereby creating a minimum pressure drop so as to maintain a high volume throughput. Thus, the inlet device of the present invention is designed so as to provide improved, and preferably maximised, separation efficiency as compared to known inlet devices under otherwise similar or identical circumstances.

Furthermore, the inlet device of the present invention is robust, compact, easily removable and replaceable and, conveniently, it can be retrofitted to existing separation vessels as well as being provided for new separation vessels.

The hollow body of said inlet device may be formed with a neck portion having a diameter, DN, and a skirt portion having a diameter the diameter of the neck portion being less than the diameter of the skirt portion, such that the unit volume of the device in the neck portion is less than the unit volume of the device in the skirt portion.

The neck portion may be provided with the plurality of inlets, whilst the skirt portion may be provided with the plurality of outlets.

In one embodiment of the invention, the series of concentric apertures divided by at least one radial vane which form the plurality of inlets is preferably symmetrically divided by the said vane. Consequently, the series of adjacent, at least partially annular apertures, which form the plurality of outlets, and which are also subdivided by the said radial vane, would also be symmetrically divided. Of course it is possible, however, for the inlet and outlet apertures to be non-symmetrically divided.

Additionally, or in the alternative, the plurality of outlets comprised in the device of the invention may be configured as a series of adjacent, fully annular apertures, rather than at least partially annular apertures.

In the inlet device of the invention, the second direction, along which an outlet portion of a channel extends, may preferably be substantially normal, i.e. substantially at 90°, to the first direction, along which the corresponding inlet portion of the channel extends.

Further preferably, the second direction may be ± 10° to a direction which is normal to the first direction, and yet preferably the second direction may be only ± 20° to a direction which is normal to the first direction. Most preferably, the second direction may be ± 30° to a direction which is normal, i.e. at 90°, to the first direction, or at an even greater angle still. The first direction may be considered as the axial direction, whilst the second direction may be considered as, or at an angle to, the radial direction.

Advantageously, the series of concentric apertures forming the plurality of inlets, and the series of adjacent, at least partially annular apertures forming the plurality of outlets, may be subdivided, and preferably symmetrically subdivided, by six or eight radial vanes. The concentric inlet apertures may be circular or substantially circular, with a pair of radial vanes being located end-to-end (forming a diametric vane) across the diameter of each circle, thus providing nested sectors as the inlet apertures.

Correspondingly, the inlet portions of the channels may be considered as formed from nested cylinders which are subdivided across their diameters. Similarly, the adjacent annular apertures, when viewed along the first direction, are provided to extend in the second direction in overlapping, sectored layers.

Preferably the plurality of inlets may comprise between eighteen and forty apertures, being provided in three, four, or five nested series of six or eight apertures. Similarly, the plurality of outlets preferably may comprise between eighteen and forty apertures, being provided in three, four or five stacked series of six or eight apertures. Such an array of apertures for each of the plurality of inlets and the plurality of outlets is believed to provide the optimum throughput efficiency for the inlet device by minimising the pressure drop therethrough and by providing sufficient control over boundary layer separation effects.

Beneficially, in the inlet device of the invention, the ratio of the area (A1) of an inlet aperture to the area (Ao) of its corresponding outlet aperture, A1:A0, may be substantially identical for each pair of inlet and outlet apertures. Such a feature is useful as it may ensure a symmetrical, uniform distribution of fluid from each outlet, with all channels experiencing a substantially equal volumetric flow rate of fluid, such that a substantially equal, if not exactly equal, share of the input fluid is expelled through each outlet aperture. The ratio (Ai:Ao) may preferably be in the range from 1:2 to 1:12, further preferably in the range from 1:4 to 1:10, and most preferably in the range of from 1:4 to 1:8. Again, it is believed that these ranges of ratios provide the optimum throughput efficiency for the inlet device by minimising the pressure drop therethrough and by providing sufficient control over boundary layer separation effects.

To facilitate the change in direction of flow moving through a channel connecting an inlet with its corresponding outlet from the first direction to the second direction, a curved channel portion may be provided between the inlet portion and the outlet portion of said channel.

The inlet device of the invention is designed to be connected to an inlet pipe provided within a fluid separation vessel. The curved channel portion of the inlet device may preferably be designed so as to have a radius of curvature that is a multiple of the diameter, D1, of the inlet pipe, typically between 1 D1 and 4D1. The inlet pipe diameter may be in the range from 15010 500 mm Advantageously, in the inlet device of the invention, the first direction, along which an inlet portion of a channel extends, may be configured so as to be substantially co-directional with the overall direction of the single-phase or multi-phase fluid flow through said inlet device.

An inlet device according to the invention can be used with flow rates typical of the application in question, for example, flow rates in the range from 50 to 600 kg/s are regularly encountered in the oil and gas production industries. By way of illustration, gas dominated input flows would have a density around SOkg/m3, whereas liquid dominated flows would have density around 1 000kg/m3.

Beneficially, the inlet device of the invention is formed from any suitably durable material, which is able to withstand the temperatures and forces (shear, abrasive, etc.) which may be imparted thereto by the input fluid, for example a high grade stainless steel.

According to a second aspect of the present invention there is provided a fluid separation apparatus, preferably a vapour-liquid separation apparatus, comprising a separation vessel and an inlet device as hereinbefore described.

The inlet device according to the invention may be used with any type of fluid separation vessel, including two-phase and three-phase separation vessels, in any of the industries described earlier, but particularly in the oil and petroleum production industries, and with vertical, horizontal and/or spherical separation vessels.

Furthermore, the inlet device may be installed on land-based process equipment, on an oil production platform tethered to the sea bed, or on a Floating Production, Storage, and Offloading (FFSO) system. Such universal usage is made possible by the design of the inlet device, the dimensions of which can easily be varied so as to achieve particular throughput characteristics for any given separation vessel.

According to a third aspect of the present invention there is provided use of an inlet device as hereinbefore described in a process for separating vapour from a liquid. The process may be used in any of the industries described earlier, but particularly in the oil and petroleum production industries for the separation of gas, oil, water and possibly sand from the multi-phase input oil-well fluid.

For a better understanding, the present invention will now be more particularly described, by way of a non-limiting example only, with reference to the following schematic drawings (not to scale) in which: Figure la is a perspective view of an inlet device according to the invention; Figure lb is a further perspective view of the inlet device shown in Figure 1 a; Figure 2 is plan view from above of the inlet device shown in Figures 1 a and lb; Figure 3 is plan view from below of the inlet device shown in Figures la and ib; Figure 4 is a side elevation of the inlet device shown in Figures la and ib; Figure 5 is a cross-sectional perspective view taken along the line A-A of the inlet device shown in Figure 2; Figure 6 is a cross-sectional perspective view taken along the line B-B of the inlet device shown in Figure 2; Figures 7a-7h are cross-sectional views of alternative inlet devices when viewed along a line similar to B-B for the inlet device shown in Figure 2; Figure 8 is a cross-sectional view of a vertical vapour-liquid separation apparatus including the inlet device shown in Figures 1 a and 1 b; Figure 9 is a cross-sectional view of a horizontal vapour-liquid separation apparatus including the inlet device shown in Figures 1 a and 1 b; and Figure 10 is a plan view from above of an alternative inlet device according to the invention.

Figures la and lb show an inlet device 10 comprising a hollow body 11 formed with a narrower neck portion 11 a which widens into a skirt portion 11 b. Neck portion 11 a is provided with a plurality of inlets 12 and skirt portion llb is provided with a plurality of corresponding outlets 13 through which a multi-phase fluid (not shown) may flow. The plurality of inlets 12 is configured as a series of concentric, circular apertures 17 which are centred about an axis which extends in a first, axial direction (A) and which are symmetrically subdivided by eight radial vanes 18; the plurality of outlets 13 is configured as a series of adjacent annular apertures 19 which are also centred about said axis and symmetrically sub-divided by said eight radial vanes 18.

As shown, inlet device 10 comprises twenty-four inlet apertures, provided in three nested series of eight apertures, and twenty-four outlet apertures, provided in three stacked series of eight apertures. The innermost inlet apertures 1 7a lead to the outlet apertures farthest from the plurality of inlets (the lowermost outlet apertures 1 9b), whilst the outermost inlet apertures 17b lead to the outlet apertures closest to the plurality of inlets (the uppermost outlet apertures 19a). As discussed earlier, the terms "uppermost" and "lowermost" define the relative locations of the series of outlet apertures in relation to the location of the plurality of inlets, and although these terms in particular refer to a preferred orientation of the inlet device when in use (as shown in Figure la), they should be construed in accordance with the actual orientation of the device.

Extending around the periphery of outermost inlet apertures 17b is an annular lip 20, in which a number (eight as shown) of fixing holes 21 are provided, to enable inlet device to be connected, preferably by means of an appropriate seal (not shown), to a vapour-liquid separation vessel (not shown).

In use, a single-phase or multi-phase fluid (not shown) is introduced into inlet device 10 in a single stream in axial direction (A) and emerges in a number of streams of substantially equal volumetric flow rate in a second direction, which as shown in Figure lb is a radial direction (Fl).

Figure 2 clearly shows inlet device 10 when viewed in plan from above, emphasizing, in particular, the manner in which the eight radial vanes 18 divide each of the three concentric circular apertures in series 17 to form nested circular sectors.

Figure 4 shows inlet device 10 when viewed from a side (the device shown having rotational symmetry), and clearly illustrates the relative dimensions of neck portion 1 la and skirt portion 11 b of body 11.

Turning to Figure 5, we see that inlet device 10 further comprises channels 14 connecting each inlet in plurality of inlets 12 with its corresponding outlet in plurality of outlets 13. Each channel 14 comprises an inlet portion 15, an outlet portion 16 and a curved channel portion 24 therebetween. Each inlet portion 15 extends from an inlet aperture in the first, axial direction (A) into and through the body to curved channel portion 24, which facilitates a change in direction of channel 14, which in turn extends to outlet portion 16 which extends to an outlet aperture in the second, radial direction (R). Thus as shown, an input fluid would undergo a change in direction of substantially 9Q0 from its input axial direction (A) to its output radial direction (R) because radial direction (R) is substantially normal to axial direction (A).

As a result of the presence of curved channel portions 24, a dimple (also referred to in the art as a centre-body) 23, centred about the central axis of device 10, results in the base plate 22 of device 10, as is best shown in Figure 3. Dimple 23 provides the necessary curvature to facilitate the change of fluid flow direction in the channels 14 extending between innermost inlet apertures 17a and lowermost outlet apertures 19b.

In Figure 6, the areas A1 of each inlet aperture are shaded with different hatching patterns, and the areas A0 of each corresponding outlet aperture are shaded with matching hatching patterns. The ratio of outermost inlet aperture to uppermost outlet aperture, AIa):Ao(a), is preferably identical with the ratio of the central inlet aperture to the central outlet aperture, AI(b):AO(bI, which is further preferably identical with the ratio of innermost inlet aperture to lowermost outlet aperture, AI(:AO(0), i.e. AI(a):Ao(a) = AI(b):AQ(b) = AI(0):AQ) = A1:A0 In Figure 6, the ratio of A1:A0 is 1:4; this is also shown in Figure 7a which further illustrate the relative dimensions of channels 14 and the relative orientation of the outlet portions 16 in the second direction to the first axial direction (A). However, other area ratios are possible, as shown in Figures 7b-7h. Thus, Figures 7b-7d illustrate the area ratio of A1:A0 as 1:8, whilst Figures 7e-7h illustrate the area ratio of A1:Ao as 1:6. In Figures 7b-7h, the relative orientation of the outlet portions 16 of channels 14 in the second direction to the first axial direction (A) are shown as varying by ± 10 ° to the radial direction (R). Correspondingly, the curved channel portions 24 in each of Figures 7b-7h have varying radii of curvature to facilitate the differing angles of orientation of outlet portions 16.

Turning to Figures 8 and 9, these illustrate vapour-liquid separation apparatus comprising a vertical separation vessel 100 (Figure 8) or a horizontal separation vessel (Figure 9) and an inlet device 10.

Vertical separation vessel 100 is provided with a single-phase or multi-phase fluid inlet 101 leading to an inlet pipe lola (of diameter Dip), a vapour outlet 102 and a liquid outlet 103. Inlet device 10 is shown as being connected in a fluid-tight manner with an appropriate seal within vessel 100 to inlet pipe lola. Inlet pipe lOla is provided above the liquid level in a primary separation section (1) of vessel 100, which is typically a first gravity separation section in which larger liquid droplets fall out of the input vapour-liquid fluid mixture (not shown) under the influence of gravity. In the secondary separation section (2), smaller particles of liquid are removed from the largely vaporous fluid, again by gravity separation and the turbulence of the gas flow is reduced. Any remaining fine liquid mist particles may be removed from the largely vaporous fluid via mist extractor (4). Liquid droplets which have formed under the influence of gravity accumulate in liquid accumulation section (3) as a bulk liquid (possibly multi-phase, e.g. oil and water), which is subsequently removed from vessel 100 via liquid outlet 103, optionally via a vortex breaker (5), or further separated into its constituent components (e.g. oil and water).

Horizontal separation vessel 200 is very similar to vertical separation vessel 100 in both its constructions and operation, and indeed like features have been provided with like reference numbers however increased in value by one hundred. Vessel 200 is thus provided with a single-phase or multi-phase fluid inlet 201 leading to an inlet pipe 201a (again of diameter a vapour outlet 202 and a liquid outlet 203. Inlet device is shown as being connected in a fluid-tight manner with an appropriate seal within vessel 200 to inlet pipe 201a. Inlet pipe 201a is provided above the liquid level in a primary separation section (1) of vessel 200, which is typically a first gravity separation section in which larger liquid droplets fall out of the input vapour-liquid fluid mixture (not shown) under the influence of gravity. In the secondary separation section (2), smaller particles of liquid are removed from the largely vaporous fluid, again by gravity separation and the turbulence of the gas flow is reduced. Any remaining fine liquid mist particles may be removed from the largely vaporous fluid via mist extractor (4).

Liquid droplets which have formed under the influence of gravity accumulate in liquid accumulation section (3) as a bulk liquid (possibly multi-phase, e.g. oil and water), which is subsequently removed from vessel 200 via liquid outlet 203, optionally via a vortex breaker (5), or further separated into its constituent components (e.g. oil and water).

With both types of separation vessels 100, 200, inlet device 10 is shown as being located above the surface of the separated liquid, however it is equally possible that the device could be submerged beneath the surface of the liquid.

Figure 10 shows alternative inlet device 500 comprising a hollow body 501 formed with a narrower neck portion 501a which widens into a skirt portion 501b. Neck portion 501a is provided with a plurality of inlets 502 and skirt portion 501b is provided with a plurality of corresponding outlets 503 through which a multi-phase fluid (not shown) may flow. The plurality of inlets 502 is configured as a series of concentric, circular apertures 507 which are centred about an axis which extends in a first, axial direction (which extends into the page) and which are symmetrically subdivided by eight radial vanes 508; the plurality of outlets 503 is configured as a series of adjacent, partially annular apertures which are also centred about said axis and symmetrically sub-divided by said eight radial vanes 508. As compared to inlet device 10 shown in plan in Figure 2 which is designed to distribute the outlet flows substantially evenly over 3600 about the first axial direction, inlet device 500 shown in Figure 10 is designed to distribute the outlet flows (shown by the eight outwardly extending arrow heads) substantially evenly over an angular range of less than 3600.

Inlet device 500 comprises sixteen inlet apertures, provided in two nested series of eight apertures, and sixteen outlet apertures, provided in two stacked series of eight apertures. The innermost inlet apertures lead to the outlet apertures farthest from the plurality of inlets (the lowermost outlet apertures), whilst the outermost inlet apertures lead to the outlet apertures closest to the plurality of inlets (the uppermost outlet apertures). As discussed earlier, the terms "uppermost' and "lowerrriost" define the relative locations of the series of outlet apertures in relation to the location of the plurality of inlets, and although these terms in particular refer to a preferred orientation of the inlet device when in use (for example, as shown in Figure la), they should be construed in accordance with the actual orientation of the device.

Although not shown in Figure 10, an annular lip may extend around the periphery of outermost inlet apertures; a number of fixing holes may be provided to enable inlet device 500 to be connected, preferably by means of an appropriate seal (not shown), to the inlet pipe supplying a fluid separation vessel (not shown).

In use, a single-phase or multi-phase fluid (not shown) is introduced into inlet device 500 in a single stream in the axial direction and emerges in a number of streams of substantially equal volumetric flow rate in a second direction (shown by the eight outwardly extending arrow heads), which is a radial direction.

With both types of separation vessels 100, 200, inlet devices 10, 500 enable the initial separation and de-foaming of bulk liquids from the multi-phase input fluid, the reduction of momentum of the output fluid so that the potential for droplet shatter, or bubble re-entrainment, is minimised, the reduction of re-entrainment of liquid into the vapour phase from the surface of the separated liquid or vapour re-entrainment into the liquid phase, and the reduction of turbulence and/or re-circulation in the liquid collection area of the vessel. It also transfers the inlet flow smoothly to the outlet, thereby creating a minimum pressure drop so as to maintain a high volume throughput.

Claims

CLAIMS: 1. An inlet device, for use with a fluid separation vessel, comprising: a hollow body provided with a plurality of inlets and a plurality of corresponding outlets, each inlet and its corresponding outlet being connected by a channel through which a single-phase or multi-phase fluid may flow, each channel having an inlet portion and an outlet portion, the inlet portion extending in a first direction through the body and the outlet portion extending in a second direction through the body, wherein the plurality of inlets is configured as a series of concentric apertures centred about an axis which extends in the first direction and subdivided by at least one radial vane, and wherein the plurality of outlets is configured as a series of adjacent, at least partially annular apertures centred about said axis and subdivided by the said at least one radial vane, whereby the outermost inlet apertures lead to the outlet apertures closest to the plurality of inlets (the uppermost outlet apertures), and the innermost inlet apertures lead to the outlet apertures farthest from the plurality of inlets (the lowermost outlet apertures).
2. An inlet device as claimed in claim 1 wherein the series of concentric apertures divided by at least one radial vane is symmetrically divided by the said vane.
3. An inlet device as claimed in claim 1 or claim 2 wherein the series of adjacent, at least partially annular apertures divided by the said at least one radial vane is symmetrically divided by the said vane.
4. An inlet device as claimed in any preceding claim wherein the plurality of outlets is configured as a series of adjacent, annular apertures.
5. An inlet device as claimed in any preceding claim wherein the second direction, along which an outlet portion of a channel extends, is substantially normal to the first direction, along which the corresponding inlet portion of the channel extends.
6. An inlet device as claimed in claim 5 wherein the second direction, along which an outlet portion of a channel extends, is ± 100 to a direction which is normal to the first direction, along which the corresponding inlet portion of the channel extends.
7. An inlet device as claimed in any preceding claim wherein the series of concentric apertures forming the plurality of inlets, and the series of adjacent, at least partially annular apertures forming the plurality of outlets, are subdivided, and preferably symmetrically subdivided, by six or eight radial vanes.
8. An inlet device as claimed in any preceding claim wherein the plurality of inlets comprises between eighteen and forty apertures, provided in three, four or five nested series of six or eight apertures.
9. An inlet device as claimed in claim 8 wherein the plurality of outlets preferably comprises between eighteen and forty apertures, being provided in three, four or five stacked series of six or eight apertures.
10. An inlet device as claimed in any preceding claim wherein the ratio of the area (A1) of an inlet aperture to the area (A0) of its corresponding outlet aperture, A1:A0, is substantially identical for each pair of inlet and outlet apertures.
11. An inlet device as claimed in claim 10 wherein the ratio (Ai:A0) is in the range of from 1:2 to 1:12, further preferably in the range of from 1:4 to 1:10, and most preferably in the range of from 1:4 to 1:8.
12. An inlet device as claimed in claim 10 or claim 11 being configured so as to divide equally the flow of single-phase or multi-phase fluid which may flow through said inlet device between each of the inlet/outlet apertures.
13. An inlet device as claimed in any preceding claim wherein a curved channel portion is provided between the inlet portion and the outlet portion of a channel.
14. An inlet device as claimed in claim 13 wherein the curved channel portion has a radius of curvature that is a multiple of the diameter, D1, of an inlet pipe provided within a fluid separation vessel to which the device is connectable, typically between 1 D1 and 4D1.
15. An inlet device as claimed in any preceding claim wherein the first direction, along which an inlet portion of a channel extends, is configured so as to be substantially co-directional with the overall direction of the single-phase or multi-phase fluid flow through said inlet device.
16. A fluid separation apparatus comprising a fluid separation vessel, and an inlet device as claimed in claim 1.
17. A vapour-liquid separation apparatus comprising a vapour-liquid separation vessel, and an inlet device as claimed in claim 1.
18. Use of an inlet device as claimed in claim 1 in a process for separating vapour from a liquid.
19. An inlet device substantially as hereinbefore described with reference to and as shown in Figures 1-7 and 10 of the accompanying drawings.
20. A vapour-liquid separation apparatus substantially as hereinbefore described with reference to and as shown in Figures 8 and 9 of the accompanying drawings.
21. Use of an inlet device substantially as hereinbefore described.