SEPARATOR FOR A MULTI-PHASE FLOW

Abstract

A separator for separating a multi-phase flow comprises: a first chamber at an upstream end of the separator, the first chamber comprising an inlet for an inlet flow to enter the first chamber; a second chamber at a downstream end of the separator, the second chamber comprising an outlet for a separated gas flow to exit the second chamber; and a mesh located between the first chamber and the second chamber for separating phases of the multi-phase flow, wherein the mesh is configured to receive the multi-phase flow from the first chamber at an upstream face of the mesh, and is configured to allow the separated gas flow to flow into the second chamber from a downstream face of the mesh.

Claims

1. A separator for separating a multi-phase flow, the separator comprising: a first chamber at an upstream end of the separator, the first chamber comprising an inlet for an inlet flow to enter the first chamber; a second chamber at a downstream end of the separator, the second chamber comprising an outlet for a separated gas flow to exit the second chamber; a mesh located between the first chamber and the second chamber for separating phases of the multi-phase flow, wherein the mesh is configured to receive the multi-phase flow from the first chamber at an upstream face of the mesh, and is configured to allow the separated gas flow to flow into the second chamber from a downstream face of the mesh, wherein the upstream face of the mesh is spaced apart from the inlet into the first chamber by a distance H.sub.1, wherein H.sub.1 is related to the mesh diameter d by the following relationship:
H.sub.1>0.5 d

2. A separator according to claim 1, wherein the mesh is rotatable.

3. A separator according to claim 1, wherein H.sub.1 is less than ten times the mesh diameter, or less than five times the mesh diameter, or less than three times the mesh diameter, or less than two times the mesh diameter.

4. A separator according to claim 1 any prcceding claim 1, wherein the second chamber at least partially projects into the first chamber by a distance H.sub.2, wherein
H.sub.2>0.5 d

5. A separator according to claim 4, wherein H.sub.2 is less than ten times the mesh diameter, or less than three times the mesh diameter, or less than two times the mesh diameter, or is less than the mesh diameter d.

6.-9. (canceled)

10. A separator according to claim 1, wherein the mesh diameter d is between 20 mm and 750 mm.

11. A separator according to claim 1, wherein the first chamber, mesh and second chamber are arranged such that flow through the first chamber to the mesh, and through the mesh to the second chamber is in a generally axial direction.

12. A separator according to claim 1, wherein flow through the first chamber to the mesh, and through the mesh to the second chamber is in a generally vertically upwards direction, and/or wherein the inlet projects into the first chamber through a bottom face of the first chamber, whereby a collection reservoir for collecting a non-gas phase from the multi-phase flow is defined at the bottom of the first chamber with an outer wall defined by the sidewall(s) of the first chamber, and an inner wall defined by the inlet, optionally wherein the collection reservoir comprises a drain for draining off the non-gas phase.

13. A separator according to claim 1, wherein flow through the first chamber to the mesh, and through the mesh to the second chamber is in a generally horizontal direction, and a collection reservoir for collecting a non-gas phase from the multi-phase flow is defined at the bottom of the first chamber, optionally wherein the collection reservoir comprises a drain for draining off the non-gas phase.

14. A separator according to claim 1, wherein the mesh has a pore density of between 10 ppi and 100 ppi.

15. A separator according to any preceding claim 1, wherein the mesh comprises an open-cell structure, optionally having either a random or regular pore structure.

16. A separator according to any preceding claim 1, wherein the first chamber and second chamber are pressure vessels, for separating a multi-phase flow pressurised to greater than atmospheric pressure, or for separating a multi-phase flow at lower than atmospheric pressure.

17. A separator according to any preceding claim 1, comprising a motor for rotating the mesh, wherein the motor comprises an output shaft, wherein the mesh is attached to the output shaft, or wherein the mesh is provided on a second shaft, and the second shaft is driven by the output shaft via a magnetic coupling.

18. A separator system comprising a plurality of separators according to claim 1, wherein the plurality of separators are arranged in parallel or in series.

19. A method of separating a multi-phase flow comprising: flowing a multi-phase flow into an upstream face of a mesh provided in a first chamber of a separator, whereby a non-gas phase is forced radially out through interconnected pores in the mesh towards the periphery of the mesh, whilst a gas phase passes axially through the mesh, out of a downstream face of the mesh into a second chamber, wherein the upstream face of the mesh is spaced apart from the inlet into the first chamber by a distance H.sub.1, wherein H.sub.1 is related to the mesh diameter d by the following relationship:
H.sub.1>0.5 d

20. (canceled)

21. The method of claim 19 comprising the use of one of a or b): a) a separator comprising: a first chamber at an upstream end of the separator, the first chamber comprising an inlet for an inlet flow to enter the first chamber; a second chamber at a downstream end of the separator, the second chamber comprising an outlet for a separated gas flow to exit the second chamber; a mesh located between the first chamber and the second chamber for separating phases of the multi-phase flow, wherein the mesh is configured to receive the multi-phase flow from the first chamber at an upstream face of the mesh, and is configured to allow the separated gas flow to flow into the second chamber from a downstream face of the mesh, wherein the upstream face of the mesh is spaced apart from the inlet into the first chamber by a distance H.sub.1, wherein H.sub.1 is related to the mesh diameter d by the following relationship:
H.sub.1>0.5 d; or b) a plurality of separators arranged in parallel or in series.

22. The method of claim 19, comprising separating gas from liquid entrained in the gas, and/or comprising separating gas from a suspension of solid particles captured in liquid droplets which are entrained in the gas and/or comprising separating a first gas from a second gas, wherein the first gas and second gas are present in a mixture of gases in the inlet flow, and the second gas is absorbed by the liquid droplets.

23. The method of claim 19, comprising rotating the mesh, optionally at a speed of 500 to 6,000 rpm.

24. The method of claim 19, wherein a flow rate of the multi-phase flow is 50 m.sup.3/hour-30,000 m.sup.3/ hour.

25. The method of claim 19, comprising collecting and draining off a non-gas phase separated from the multi-phase flow.

26.-97. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0386] Certain exemplary embodiments will now be described in greater detail by way of example only and with reference to the accompanying drawings in which:

[0387] FIG. 1 shows a vertically-oriented separator;

[0388] FIG. 2 shows a horizontally-oriented separator;

[0389] FIG. 3 shows a mesh holder for the mesh of a separator;

[0390] FIG. 4 shows a mesh holder for the mesh of a separator;

[0391] FIG. 5 shows a separator comprising a mesh holder;

[0392] FIGS. 6 and 7 show a separator comprising a fan;

[0393] FIGS. 8 to 10 show means for adding liquid within a separator;

[0394] FIG. 11 shows a separator included in a compressor system;

[0395] FIG. 12 shows a separator included in a dry gas seal system;

[0396] FIG. 13 shows a separator included in a compressor system;

[0397] FIG. 14 shows a separator included in a seismic shock system for sub-sea seismic exploration;

[0398] FIG. 15 shows a separator included in an exhaust gas recirculation system;

[0399] FIG. 16 shows a separator included in an exhaust gas cleaning system;

[0400] FIG. 17 shows a separator included in a kitchen ventilation system;

[0401] FIG. 18 shows efficiency as a function of the volumetric flow rate for a separator with a mesh rotating at 3000 rpm, and a separator with the mesh stationary;

[0402] FIG. 19 shows efficiency as a function of the volumetric flow rate for separators with two different values of the parameter t/H.sub.3;

[0403] FIG. 20 shows efficiency as a function of the volumetric flow rate for separators with two different values of the parameter s; and

[0404] FIG. 21 shows efficiency as a function of the volumetric flow rate for separators with two different values of the parameter H.sub.1/D.

DETAILED DESCRIPTION

[0405] FIG. 1 shows a gas/liquid separator 100. The separator comprises a first chamber 22 and a second chamber 28. Between the first chamber 22 and second chamber 28 is provided a mesh 24. The separator 100 receives a gas/liquid flow 10 (i.e. an inlet flow comprising gas containing entrained droplets of liquid). The gas/liquid flow 10 enters the first chamber 22 of the separator through an inlet 20, at an upstream end of the separator 100.

[0406] The mesh 24 comprises a metal foam, and is structurally self-supporting. The mesh 24 has an open-cell structure comprising a plurality of passageways formed from interconnected pores in the metal structure. The mesh 24 has a random cell structure. In this embodiment, the porosity (i.e. the volume of the pores divided by the total volume) of the mesh 24 is approximately 90%. The average pore diameter is 1 mm. The pore density is 10 ppi. In this embodiment, the mesh 24 comprises aluminium. The mesh 24 is rotated about an axis A by a motor 58.

[0407] The mesh 24 has a diameter d, and the first chamber 22 has a diameter D. In the present embodiment, the diameter d of the mesh is 150 mm and the diameter D of the first chamber is 250 mm. The distance s between the outer periphery 24c of the mesh 24 and the wall 22a of the first chamber 22 is 50 mm. The distance s and diameter d of the mesh are then related as follows: s=0.33d.

[0408] The mesh 24 is positioned such that the upstream surface 24a of the mesh 24 is a distance H.sub.1 from the top of the inlet 20. In the present embodiment, the distance H.sub.1 is twice the diameter of the mesh 24 (i.e. H.sub.1=2d). Such an arrangement leads to good separation efficiency. In this embodiment, the distance H.sub.1 is 300 mm.

[0409] The mesh 24 is positioned such that the downstream surface 24b of the mesh 24 is a distance H.sub.2 from the top 22b of the first chamber 22. In the present embodiment, the distance H.sub.2 is equal to the diameter of the mesh 24 (i.e. H.sub.2=d). Such an arrangement leads to good separation efficiency. In this embodiment, the distance H.sub.2 is 150 mm.

[0410] In this embodiment, the thickness t of the mesh 24 is 100 mm. The thickness t and diameter d of the mesh are then related as follows: t=0.67d. The mesh rotates at approximately 3,000 rpm.

[0411] As the gas/liquid flow 10 passes through the mesh 24, the liquid is centrifuged and coalesces within the pores of the mesh 24. The flow of coalesced liquid 40 is forced radially outwards towards the outer periphery 24c of the mesh 24 by the centrifugal force generated as a result of the rotation of the mesh 24. The flow of coalesced liquid 40 is spun across the gap between the outer periphery 24c of the mesh 24 and the wall 22a of the first chamber 22, and collects on the wall 22a of the first chamber 22. The flow of coalesced liquid 40 then flows down the wall 22a of the first chamber 22, to collect in the liquid collection reservoir 42 in the base of the first chamber 22. The liquid collection reservoir 42 is an annular space defined by the wall 22a and base 22c of the first chamber 22 and the outer wall 20a of the inlet 20. Liquid (also possibly including solid particles) collected in the liquid collection reservoir 42 can be drained away through drainage pipe 44, which in this example, includes a valve 46.

[0412] Meanwhile, the flow of gas 30, which no longer contains liquid contaminants, passes axially through the mesh 24, into a second chamber 28 and out of the second chamber 28 through an outlet 32. Whilst flow through the first chamber 22, mesh 24 and second chamber 28 is generally axial, flow out of the outlet need not be in the axial direction, i.e. the outlet 32 from the second chamber 28 can have any orientation. In FIG. 1, the outlet 32 is perpendicular to the axis of the separator.

[0413] At the downstream surface 24b of the mesh 24, around the outer periphery, is provided a seal 26 which prevents any flow into the second chamber 28, except through the mesh 24. In this embodiment, the seal 26 is a labyrinth seal. However, other types of seal may alternatively be used, or no seal may be present.

[0414] The separator 100 shown in FIG. 1 is vertically oriented, such that the first chamber 22 is arranged vertically below the second chamber 28, and the inlet 20 to the separator comprises a vertically oriented pipe which protrudes vertically upwards into the first chamber 22 in the direction towards the mesh 24. Flow through the separator 100 then broadly follows the upwards vertical direction, and liquid separated from the multi-phase flow collects in a collection reservoir 42 at the base of the first chamber 22, where the liquid collection reservoir 42 is an annular space defined by the wall 22a and base 22c of the first chamber 22 and the outer wall 20a of the inlet 20.

[0415] The separator 100a shown in FIG. 2 is similar to the separator 100 shown in FIG. 1, and like features are not explained in detail again here. Instead, differences between the two embodiments will be explained. Whilst the separator 100 shown in FIG. 1 is vertically oriented, the separator 100a shown in FIG. 2 is horizontally oriented. Flow through the separator 100a broadly follows the horizontal direction, from left to right as shown in FIG. 2. In this embodiment, rather than the inlet 20 being a vertically oriented pipe, it is instead a horizontally oriented pipe. The bottom of the first chamber 22 forms a liquid collection reservoir 42a, with a drain to drain off the collected liquid.

[0416] Whatever the orientation of the separator, flow from the inlet 20 to the first chamber 22, through the mesh 24 and into the second chamber 28 is in a broadly axial direction.

[0417] FIGS. 3 and 4 show mesh holders 50, 50a for the mesh 24 of a separator. Either mesh holder 50, 50a may be used in any of the separators described herein, but the use of such a mesh holder is not essential to the operation of the described separators. The mesh may be held by any form of support structure which allows the mesh to be rotated.

[0418] FIG. 3 shows a perspective view of a first mesh holder 50, with the mesh 24 shown slightly withdrawn from its position within the mesh holder 50, to aid visibility of the structure.

[0419] The mesh holder 50 comprises a rigid cylindrical body portion 52 extending between a first end and a second end. The second end comprises a plurality of fan blades 56 (in this case, six blades) extending inwardly from the cylindrical body portion 52. These fan blades 56 are configured such that the mesh holder 50 operates as an axial fan when the mesh holder 50 is rotated, thereby compensating (at least partially) for the pressure loss through the mesh 24, and helping to draw flow through the mesh 24. The mesh holder 50 comprises a central axle 54, and the fan blades 56 extend from the cylindrical body portion 52 inwardly to the central axle 54.

[0420] At the first end of the rigid cylindrical body portion 52, the mesh holder 50 is open so as to receive the mesh. The cylindrical body portion 52 overlaps the outer periphery of the mesh 24 at the downstream end of the mesh 24, so that the mesh 24 is inserted a short distance into the first end of the cylindrical body portion 52 (for example, 5 mm). The mesh holder 50 provides a rigid outer support for the mesh 24. The cylindrical body portion 52 comprises a slanted inner lip 52a to drain away any liquid reaching the mesh perimeter at this location towards the sides of the mesh 24 which are not covered by the cylindrical body portion 52. The slanted inner lip 52a also defines the extent to which the mesh 24 can be inserted into the mesh holder 50—when the mesh 24 abuts against the inner lip 52a, it cannot move further into the mesh holder 50.

[0421] In this embodiment, the mesh 24 is glued round its outer periphery to secure it within the mesh holder 50. Alternatively, the mesh is not glued, but is secured by a tight interference fit with the mesh holder 50. Securing the mesh around its periphery (either by adhesive or using an interference fit) means that there is no overlap between the mesh holder 50 and the upstream face of the mesh 24. Any overlap with the mesh holder 50 and the upstream face of the mesh 24 results in a degree of blinding of the mesh 24 to the flow into the mesh 24, and this is generally to be minimised or avoided. The mesh 24 and mesh holder 50 may also be adhered to each other where the central axle 54 of the mesh holder 50 abuts against the downstream face of the mesh 24 received within the mesh holder 50.

[0422] FIG. 4 shows a cross-sectional view of a similar mesh holder 50a with the mesh 24 in the installed position within the mesh holder 50a. This mesh holder 50a differs from the mesh holder shown in FIG. 3 by virtue of the means of attachment between the mesh 24 and the mesh holder 50a. In the embodiment shown in FIG. 4, the mesh 24 comprises a through-hole 24d coaxial with a central axis of the mesh. The mesh 24 is secured to the mesh holder 50a with a fastener 55 which passes through the through-hole and fastens to the central axle 54 of the mesh holder 50a. The fastener comprises a wide end portion 55a that is wider than the through-hole 24d, which abuts the upstream face 24a of the mesh 24.

[0423] FIG. 5 shows the mesh holder 50 of FIG. 3 in a horizontal separator 100b (but equally the mesh holder 50a of FIG. 4 could be used, and/or the separator could be vertically-oriented). The central axle 54 of the mesh holder 50 is integral with an output shaft of the motor 58. Alternatively, the central axle 54 of the mesh holder 50 could be rotated by the motor output shaft via a magnetic coupling between the central axle 54 and the output shaft.

[0424] As also shown in FIG. 5, an outer periphery of the cylindrical body portion 52 of the mesh holder 50 forms a sealing surface that contacts an inner wall of the second chamber.

[0425] As noted above, the mesh holder is configured with fan blades 56 to act as an axial fan when rotated, to help draw the multi-phase flow into the mesh 24, and the separated gas-flow out of the mesh 24. This compensates (at least partially) for pressure losses through the mesh 24.

[0426] As an alternative to integrating an axial fan with the mesh holder, the axial fan functionality can be moved away from the mesh holder, by providing axial fan blades separately from the mesh holder. This is shown in FIGS. 6 and 7. In FIG. 6, the separator 100c comprises a fan 59 provided on a motor shaft on the opposite side of the motor 58 from the mesh 24. In FIG. 7, the separator 100d comprises a fan 59 provided on a motor shaft between the motor 58 and the mesh 24. In both cases, the motor 58 is arranged to drive rotation of both the mesh 24 and the fan 59. The fan 59 in either case may have any configuration suitable for producing an appropriate pressure change. The fan 59 may have between 2 and 10 blades, for example 6 blades.

[0427] Whilst FIGS. 6 and 7 show horizontally-oriented separators, clearly the configuration of the fan 59 and motor 58 illustrated therein could equally be applied within a vertically-oriented separator.

[0428] FIGS. 8, 9 and 10 show possible configurations for separators incorporating a nozzle or a plurality of nozzles for spraying a liquid into inlet flow or onto the mesh. This can be done to achieve one or more of the following effects: [0429] 1) cleaning of the mesh, by removing accumulated contaminants stuck to the mesh; [0430] 2) wetting the mesh surface, so that contaminants have difficulty sticking, thereby maintaining the mesh in a clean state; [0431] 3) capturing solid particles or oil-based droplets within liquid droplets, to allow the solid/oil-based particles to be separated from the multi-phase flow; [0432] 4) capturing a particular gas within liquid droplets, to allow that gas to be separated from the multi-phase flow; and [0433] 5) fire suppression.

[0434] The liquid sprayed into the inlet flow or onto the mesh comprises one of more of: water, detergent, surfactant, alcohol, fire-suppressant. This can be chosen taking into consideration the particular use of the separator, the types of particles present in the inlet flow, and the likely problems that these pose.

[0435] The separators of FIGS. 8, 9 and 10 incorporate a reservoir (not shown) for holding the liquid to be added and a pump (also not shown) for pumping the liquid from the reservoir to the nozzle.

[0436] FIG. 8 shows a separator 100e comprising a nozzle 60a upstream of the mesh 24. A nozzle positioned here sprays additional liquid into the inlet flow, allowing contaminants to be entrained in droplets of the additional liquid before they hit the mesh 24. Because the nozzle 60a is upstream of the mesh, liquid can be added during operation of the separator; any added liquid is then separated from the gas flow via the mesh, in the same way that liquid present in the inlet flow is separated from the gas-flow.

[0437] FIG. 9 shows a separator 100f comprising a nozzle 60b downstream of the mesh 24. In this case, liquid is only added through the nozzle 60b when the separator is not operational, since otherwise, liquid is added back into the separated gas flow. Providing a nozzle 60b in this location allows the mesh to be cleaned when the separator is not operating.

[0438] FIG. 10 shows an alternative configuration for a nozzle, referred to as an “at-mesh” configuration. Here, the mesh 24 is mounted on an axle 70, and the axle 70 comprises a blind central bore 70a running a short distance into the axle 70. Two (or more) radial passages 70b run from the central bore 70a out of the axle 70. The radial passages 70b exit the axle 70 at positions which overlap with the mesh 24, i.e. the mesh 24 covers over the radial passages 70b. A pipe 60c is configured to spray liquid up into the central bore 70a, through the radial passages 70b, and into the interior of the mesh. Such a configuration allows the mesh to be cleaned when the separator is not operating. Additionally, liquid can be sprayed into the mesh during operation of the separator. Any liquid added into the mesh in this way is separated from the separated gas stream under the action of the mesh.

[0439] In each case, the particular characteristics of the liquid addition (for example, the flow rate, droplet size produced by the nozzle(s), and the spray pattern (for example, flat fan, full cone, and mist)) can be chosen according to the particular characteristics of the multi-phase flow received by the separator.

[0440] The additional liquid added into the separator can be drained away via the same drain system incorporated into the separator to drain off any non-gas phase separated out of the multi-phase flow. Drainage may be continuous, particularly in cases where additional liquid is added continuously to the multi-phase flow during operation of the separator.

[0441] Whilst the nozzles shown in FIGS. 8 and 9 are incorporated into vertically-oriented separators, they could of course be integrated into horizontally-oriented separators (or separators with any orientation). Moreover, nozzles of the kind shown in FIGS. 8, 9 and 10 may be provided all three together or in any combination of two of the nozzles in one separator. Any number of nozzles can be provided at any of the upstream, downstream or at-mesh locations.

[0442] FIG. 11 shows a separator 100 included upstream of the inlet of a compressor 300. Intake gas for use by compressors 300 may not always be clean. In particular, it may include liquids and solid particles. Over time, these may cause damage to the internal components of the compressor 300. Installing a separator 100 as disclosed herein prior to the compressor 300 intake can largely eliminate such contaminants from the intake gas.

[0443] FIG. 12 shows a separator 100 included upstream of an intake to a dry gas seal 320. For the dry gas seal 320 to operate correctly and safely, the feed gas must be very dry and clean. Installing a separator 100 as disclosed herein to process the feed gas prior to feeding it to the dry gas seal 320 can largely eliminate contaminants from the feed gas.

[0444] FIG. 13 shows a separator 100 included downstream of an outlet of a compressor 300. It is common for compressors 300 to bleed lubricants into the compressed gas. Over time, rubber particulate matter from worn seals can also make its way into compressed gas. The lubricant and rubber particles collect in gas lines downstream of the compressor, and can create a fire and explosion hazard. Installing a separator 100 as disclosed herein at the outlet of the compressor 300 is a relatively cheap and efficient way to remove lubricant and rubber particles from the compressed gas.

[0445] FIG. 14 shows a separator 100 included in a seismic shock system for sub-sea seismic exploration. The system comprises a compressor 300 which feeds compressed gas to a manifold 340. Gas lines 350 downstream of the manifold 340 extend to cannons 360 that release the compressed gas in a burst, creating the seismic shock that is recorded in order to carry out the sub-sea seismic exploration. A separator 100 can be installed before or after the manifold 340 (installation upstream of the manifold 340 is shown in FIG. 14), in order to reduce the presence of lubricant, rubber particles and other possible contaminants from the compressed gas in the gas lines 350.

[0446] FIG. 15 shows two parallel separators 100 (of course a greater number of separators could be used in parallel) in an exhaust gas recirculation system. Such a system takes a portion of the exhaust gas from an engine 380 (in this example, a marine diesel engine), cleans it in the separators 100, then feeds the cleaned gas to a fan/turbo compressor 370 which feeds the cleaned gas back into the engine 380. This reduces the combustion temperature in the engine 380, and thereby reduces the production of pollutant NOx gases.

[0447] The exhaust contains particles and liquids, and if the exhaust is not cleaned in the separators 100, these contaminants can eventually destroy the fan/compressor 370. In order to remove the finest carbon particles, the exhaust gas flow can be sprayed (for example, within the separator) with a liquid such as water and detergents/surfactants. This allows the fine carbon particles to be captured by the water droplets, to then be separated from the gas flow.

[0448] FIG. 16 shows two parallel separators 100 (of course a greater number of separators could be used in parallel) in an exhaust gas scrubbing system. Such a system takes the exhaust gas from an engine 380 (in this example, a marine diesel engine), showers it with brine in a chamber that allows misted brine to interact with the exhaust flow for around 1 to 3 seconds before it arrives in the separator, cleans it in the separators 100, then exhausts it to the atmosphere.

[0449] FIG. 17 shows a separator 100 in a kitchen ventilation system. Using cooking equipment 400 produces air laden with water vapour and fat droplets etc. Fatty deposits in kitchen ventilation systems are a serious fire risk and so ideally, such particles should be removed from the air entering the ventilation system. As shown in FIG. 17, air is drawn into a ventilation hood 410 and through a separator 100. The separator 100 separates liquids and fat droplets from the air stream, and allows only clean air to flow into the ventilation duct 420.

[0450] FIG. 18 shows efficiency of a separator as a function of the gas flow rate Q (in m.sup.3/hour) for two cases. Efficiency is defined as follows:

[00001]$100\times \frac{\begin{array}{c}\mathrm{mass}\mathrm{of}\mathrm{the}\mathrm{non}-\mathrm{gas}\mathrm{phase}\\ \mathrm{separated}\mathrm{from}\mathrm{the}\mathrm{multi}-\mathrm{phase}\mathrm{flow}\end{array}}{\begin{array}{c}\mathrm{mass}\mathrm{of}\mathrm{the}\mathrm{non}-\mathrm{gas}\mathrm{phase}\mathrm{initially}\\ \mathrm{present}\mathrm{in}\mathrm{the}\mathrm{multi}-\mathrm{phase}\mathrm{flow}\end{array}}$

[0451] In the first case, the mesh is rotated at 3000 rpm. Efficiency of the separator is above 95% for flow rates from 100 m.sup.3/hour to around 450 m.sup.3/hour. In the second case, the mesh is not rotated, and efficiency falls rapidly at higher flow rates.

[0452] FIG. 19 shows efficiency of a separator as a function of the gas flow rate Q (in m.sup.3/hour) for two cases with different values of mesh thickness t (shown as a fraction of H.sub.3, the total height of the separator vessel. In the first case, t/H.sub.3 is 0.0014. In the second case, t/H.sub.3 is 0.0006. More efficient separation is achieved in the second case (smaller mesh thickness) at higher flow rates.

[0453] FIG. 20 shows efficiency of a separator as a function of the gas flow rate Q (in m.sup.3/hour) for three cases, each with a different value of s (the distance between the outer periphery of the mesh and the wall of the first chamber). Efficiency remains high even at high flow rates for the largest value of s.

[0454] FIG. 21 shows efficiency of a separator as a function of the gas flow rate Q (in m.sup.3/hour) for two cases with different values of H.sub.1, shown in comparison to D, the diameter of the separator. In the first case, H.sub.1/D is 5, and in the second case, H.sub.1/D is 10. The efficiency of separation is higher in the second case. This demonstrates that higher values of H.sub.1 are advantageous.