GB2362118A

GB2362118A - Cyclone separator tube with a thinning in an outer wall opposite to an inlet allowing closer stacking, also a related vessel, assembly and stacking method

Info

Publication number: GB2362118A
Application number: GB0111133A
Authority: GB
Inventors: Peter Gould; Martin Dennis Grewer
Original assignee: KGD PROCESS INTERNAT Ltd
Current assignee: KGD PROCESS INTERNAT Ltd
Priority date: 2000-05-09
Filing date: 2001-05-08
Publication date: 2001-11-14
Anticipated expiration: 2021-05-08
Also published as: GB0011026D0; GB0111133D0; GB2362118B

Abstract

A cyclone separator tube has an inlet end 21, and underflow outlet end (34, fig 10) with a generally concentric interior therebetween and a thinning in the outer wall in a region 6 generally opposite the inlet end 21, so such that the tube has eccentric / non-concentric outer wall 5,6. This arrangement may allow the closer stacking of cyclone tubes within a parallel array without reducing their inner circumferences, in comparison to standard, uniform thickness walled cyclones as can be seen in the transition from fig.3 to fig.4. Also disclosed is a cyclone separator comprising an array of such cyclone tubes in a parallel array in a pressure vessel (10, fig.5). Also disclosed is a cyclone separator assembly, including a spacer (29, fig.7, 39, fig.11) providing mechanical support for cyclone tubes between adjacent wall member (14, 15, fig.5) of a cyclone separator assembly (10, fig.5). Further disclosed is a method of increasing the packing density of an existing standard cyclone separator by replacing its cyclone tubes with those described above along with a number of supporting components.

Description

2362118 CYCLONE SEPARATOR ASSEMBLY AND METHOD This invention relates to

cyclone separators, particularly but not exclusively to hydrocyclone separators such as those used to separate out the liquid constituents of oily water.

Cyclone separators have been known for many years and typically consist in the case of hydrocyclone separators of a generally cylindrical hollow pressure retaining vessel divided into three chambers by dividing plates disposed generally transversely to the cylindrical axis. The central chamber has a connection nozzle for the fluid mixture inlet and the two end chambers collect the is separated liquids, the first chamber for the less dense liquid and the second chamber for the more dense liquid.

Each chamber has various connection nozzles permitting the liquids to be removed from the vessel and at least one hydrocyclone separator tube is disposed through openings in each of the dividing plates.

For maximum packing efficiency a number of such separator tubes may be evenly spaced around one or more centrally disposed tube or tubes so that for any given internal diameter of the pressure vessel a typical configuration could be six separator tubes surrounding a seventh tube, 2 although it will be understood that other packing arrangements may be used.

A feature of cyclone separator tubes is that they must have one or more inlet ducts whereby the fluid to be separated out, such as liquid in the form of oily water, can be introduced tangentially, thereby causing the fluid mixture to rotate within the tube and f orm. a vortex in the centre comprised of less dense fluid. Since the outlet end of the tube is narrower than the inlet end due to the tube at least partially tapering inwardly along its length, the speed of the fluid mixture rotation increases or is maintained along the length of the tube. As a consequence it will be appreciated that with such tubes being is conventionally entirely concentric the maximum number of tubes which can be packed within the pressure vessel is largely dictated by the maximum external diameter of the tubes, which occurs at a point close to the one or more inlet ducts of each tube.

The present invention is derived from the realisation that whilst the interior of a cyclone separator tube must necessarily be mostly concentric to a common central axis, nevertheless the tube wall does not need to be uniformly thick and hence externally concentric about the same common axis. Substantial savings in space and hence increased packing efficiency can therefore be achieved if the 3 external diameter at the inlet end at least is made non concentric with the interior. With this arrangement, more tubes may be confined within the pressure vessel to thereby make the entire separator assembly more efficient per unit volume.

According to a first aspect of the invention there is provided a cyclone separator comprising or including a pressure vessel containing one or more cyclone separator tubes, the or each tube having an inlet end, an outlet end 0 and a concentric interior therebetween, characterised in that the outer wall of the or each tube is non-concentric with the interior thereof, at least at the inlet end of the tube, to thereby increase the available packing density is within the pressure vessel.

With this arrangement it is found that by positioning the separator tubes such that, generally speaking, the thickest wall of one tube is disposed next to the thinnest wall of an adjacent tube, it is possible to increase the number of tubes present within a given pressure vessel even though the same internal diameter and shape of each tube is retained as compared with conventional tubes.

In a second aspect of the invention there is provided a method of replacing internal components of conventional cyclone separator assemblies with components which include 4 cyclone separator tubes according to the invention and dimensionally compatible accessories therefor to thereby increase the number of tubes that can be packed within the pressure vessel.

According to a third aspect of the invention the cyclone separator assembly optionally comprises or includes spacer means for fitting over or around one end of the or each separator tube to provide localised mechanical support between adjacent wall members of the pressurevessel, 0 through at least one of which the or each tube extends, thereby permitting axial movement of the or each tube whilst retaining the mechanical integrity of said one or each wall member.

Conveniently, the angular collar includes a shoulder portion for supporting a local portion of the pressure vessel wall through which the overflow exit end of the separator tube extends. Alternatively, the spacer may comprise a pair of spacer bars connected together by a web, and from a central portion of which extends a stud adapted to be received within a correspondingly shaped bore in the overflow exit end of a separator tube within the cyclone separator assembly, the spacer bars Providing the required localised mechanical support.

According to a fourth aspect of the invention there is provided a cyclone separator tube having an inlet end, an underflow outlet end and a concentric interior there- between, characterised in that the outer walls of the tube are non-concentric with the interior thereof, at least at the inlet end of the tube, the tube walls being relatively thick in this region compared to the thickness of the tube walls diametrically opposite thereto.

Preferably, the overflow exit end is in the 0 f orm of a hollow spigot coaxial with the major axis of the interior of the tube, which spigot may include an exit duct in the side wall thereof. The free end of the spigot may also include a slot adapted to, in combination with formations is on or in a cyclone separator into which the cyclone separator tube is to be fitted, prevent rotation of the tube about its major axis.

The invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 shows a cross-section of the inlet end of a conventional cyclone separator tube; Figure 2 shows a corresponding cross-section of a cyclone separator tube for a cyclone separator assembly in accordance with the invention; 6 Figure 3 shows a conventional configuration of the separator tubes of Figure 1 within a pressure vessel; Figure 4 shows the corresponding configuration using the separator tubes of Figure 2; Figure 5 is a general assembly drawing showing a cyclone separator assembly according to the invention incorporating the separator tubes of Figure 2; 0 Figure 6 is a sectional side view of a f irst embodiment of a separator tube according to the invention; is Figure 7 is a detail sectional side view of the tube of Figure 6 shown installed in the pressure vessel of Figure 5, only part of which is shown; Figure 8 is a sectional view along the lines A-A of Figure 20 7; Figure 9 is a sectional view along the lines B-E of Figure 7; Figure 10 is a view corresponding to that of Figure 6 but showing a sectional side view of an alternative separator tube according to the invention; 7 Figure 11 is a view corresponding to that of Figure 7 showing the separator tube of Figure 10 installed ina pressure vessel with the aid of a novel spacer collar, and Figure 12 is an end view of the spacer collar of Figure 11 from the direction "C-C".

Referring firstly to Figure 1, there is shown a simplistic sectional view of the inlet end of a conventional cyclone separator tube 1 having a fluid inlet duct 2 comprising a passage through which a jet of fluid, shown arrowed, can be injected tangentially under pressure into the inside 3 of the tube 1 to thereafter circulate in the manner as indicated. As will be appreciated by those skilled in the art, because of the fluid rotation within the tube and because the tube tapers inwardly towards its underflow outlet end (not shown) it is possible to separate fluid such as oily water into its constituent parts with the denser pure water occupying the outermost regions of the inside of the tube 1 and the less dense oil occupying a central position, at which respective positions the purified water exits via the underflow outlet and the oil may then be drawn off in the opposite direction through a centrally disposed conduit, or overflow outlet, (not shown) as described, by way of example only, in UK Patent No. GB 2 258 174 B and European Patent Application No. EP 0 815 945, 8 the disclosures of each of which are incorporated herein by reference.

In Figure 2 there is shown a cyclone separator tube 4 for use in a cyclone separator assembly according to the first aspect of the invention in which it will be seen that the side walls are not uniformly'thick and the inside wall 4b is therefore not concentric with the outside wall 4a even though the tube 4 is of the same internal diameter as the tube 1 of Figure 1. This results in the tube 0 4 having a relatively thick side shown generally at 5 and a relatively thin side shown generally at 6 with the external diameter of the tube therefore being correspondingly reduced as compared with the external diameter of the tube 1 of Figure is 1.

The tube 4 has a partially curved inlet duct 7 adjacent to which is a recessed area 8 having a smooth profile. This shaping allows liquid, such as oily water, to flow smoothly into the duct 7 with little or minimal risk of shear occurring to an oil particle or droplet, although it will be understood that the inlet duct 7 could instead take the form of that shown in Figure 1 if desired.

With the configuration of the tubes 4 being non-concentric this allows for more tubes to occupy the same space than for the tubes 1 shown and described with reference to 9 Figure 1, whilst retaining sufficient material around the inlet to allow it to be shaped satisfactorily in order to avoid or minimise the risk of droplet shear occurring.

In Figure 3 it will be seen that a total of seven conventional tubes 1 can be packed reasonablyclosely within the confines of a cylindrical pressure vessel 9 with six tubes 1 surrounding a centrally disposed seventh tube 1.

In contrast, from Figure 4 it will be seen that with the non-concentric tubes 4 of the invention, if they are orientated in the manner shown with the thin walled portions 6 generally being positioned adjacent to the thick walled portions 5, it is possible to position a total of nine such tubes 4 into the same sized pressure vessel 9 as is shown in Figure 3 even though the internal diameter of all of the tubes 4 is identical to that of the tubes 1. As will be appreciated, this effectively increases the efficiency of the apparatus in terms of compactness and flow rates of fluids such that in practice is has been found that up to 20% increase in efficiency can be achieved over conventionally packed pressure vessels.

In Figure 5 there is shown a sectional side elevation of a hydrocyclone separator assembly according to the invention in which a pressure vessel shown generally at 10 comprises a fluid inlet chamber 11 a first outlet chamber shown generally at 12 and a second outlet chamber 13. The first outlet chamber 12 is defined by an end plate 14 secured to a recessed dividing plate 15 having an overflow outlet port 16 to allow the exit of less dense fluid from the separator in the direction shown arrowed.

The second outlet chamber 13 is largely cylindrical in shape but has a rounded off end portion 17 as is conventional in pressure vessel design. The second chamber 13 is closed off by means of an annular plate 18 and includes an underflow outlet port 19 to allow the exit of denser fluid than that exiting from the overflow outlet port 16, again in the direction shown arrowed.

is The central chamber 11 is primarily cylindrical and is closed off by, respectively, the recessed plate 15 and annular plate 18, through coaxial bores in each of which extend a number of cyclone separator tubes 4 described in more detail in Figures 6 to 9. The central chamber 11 includes an inlet port 20 through which fluid to be separated, such as oily water, can be introduced under pressure in the direction shown arrowed.

It should be noted that, if desired, the cyclone separator tubes 4 may be partially replaced by blank tubes, thereby permitting more or less fluid to pass through the pressure 11 vessel whilst maintaining required process efficiency of oil and water separation. Such blank tubes may be hollow or solid but will not allow the fluid to pass from the inlet chamber to any other chamber.

Turning now to Figure 6, there is shown in section the inlet end of a separator tube 4 in accordance with the invention in which the inside walls 4b are concentric about a common internal central axis whereas the outer walls 4a are not and include a relatively thick-walled region shown generally at 5 into which has been cut a suitably shaped and slotted inlet duct 21 for permitting fluid to be separated to be injected tangentially therein, and a thin walled section shown generally at 6, the regions 5 and 6 is corresponding to those shown and described with reference to Figure 2.

The separator tube 4 tapers inwardly towards its underflow outlet end (not shown) and at the opposite end includes a small centrally disposed overflow outlet orifice 22 to allow for escape of lighter fluid, such as oil if the initial mixture is oily water, in the direction shown arrowed. The tube 4 also includes an annular groove 23 around its periphery into which an 0-ring seal can be introduced.

12 A hollow spigot 24 extends from the closed end of the tube 4 and is coaxial with the overflow outlet orifice 22. The spigot 24 includes an open-ended slot 25 and an exit duct 26, the functions of which will now be described with reference to Figures 7 to 9.

In Figure 7 the generally closed end of the tube 4 is shown extending through a bore 27 in the recessed plate 15 and an O-ring seal 28 is shown received within the annular slot 23 of the tube 4 to thereby seal the space therebetween. The free end of the spigot 24 is shown abutting the inside face of the end plate 14 and is surrounded by a spacer element in the form of a generally cylindrical spacer collar 29 having a flanged shoulder 30 to provide mechanical support for the recessed plate 15 around the bore 27 when pressurised by the introduction of fluid under pressure into the inlet chamber 11. It is a feature of this aspect of the invention that the number of spacer collars 29 can be varied to suit the degree of support required for the recessed plate 15 such that all or only some of the spigots 24 may have associated spacer collars 29 around them.

As can be seen from Figure 8, the spacer collar 29 has an inwardly disposed key portion 31 of size sufficient to receive the slotted portion 25 of the spigot 24.

13 In Figure 9 it will be seen that a central portion of the collar 29 does not include the key 31 but is instead provided with an opening 32, the slot 25, duct 26 and opening 32 collectively permitting escape of less dense fluid exiting the inlet chamber 11 via the overflow outlet orifice 22.

As will be appreciated, the generally cylindrical spacer collar 29 transmits the localised load exerted on the recessed plate 15 to the end plate 14, thereby 0 minimising the bending of the plate 15 such that its thickness, weight and cost can be kept to a minimum. A further advantage of this design is that longitudinal movement of the separator tubes 4 is not restricted so that consequent mechanical stresses on them are kept to a minimum.

In Figures 10 to 12 respectively there is shown a second embodiment of the invention in which a separator tube shown generally at 33 has an underflow end 34 which is cylindrical externally, as opposed to being tapered. At the other end there is a spigot 35 having a slotted portion 36 corresponding, respectively, to spigot 24 and slotted portion 25 of the separator tube shown with reference to Figures 6 to 9. However, in this embodiment the slot 36 terminates before reaching the end of the spigot 35 and, as can be seen more clearly with reference to Figure 10, the free end of the spigot 35 is provided with a further slot 14 37 disposed orthogonally relative to the slot 36. The slot 37 is adapted to fit over and around a central web portion 38 of a spacer element shown generally at 39 which includes a pair of spacer bars 40,41 extending from respect ends of the web 38. Extending centrally from the web 38 is a location stud 42 of diameter corresponding to the internal diameter of the spigot 35.

As can be seen with reference to Figure 11, the spacer element 39 provides mechanical support between the pressure vessel end plate 14 and the recessed plate 15, thereby providing mechanical support for the latter from pressure within the fluid inlet chamber 11. However, in this embodiment it will be apparent that an area of potential mechanical weakness, namely the opening 32 in the collar 29 of the embodiment described in Figure 7, is dispensed with in favour of the spacer bars 40,41 which, because they are held at a position orthogonal to the underflow exit slot 36 by, in combination, the location of the stud 42 within the spigot 35 and the location of the slotted end 37 thereof about opposing sides of the web 38 the spacer bars 40,41 therefore never interfere with the flow of fluid.

Although the realisation that cyclone separator tubes do not have to be concentric such that cyclone separator assemblies can be made in accordance with the invention with a higher packing density of separator tubes than is conventional cyclone separators with concentric separate tubes, thereby increasing the overall efficiency, nevertheless it is also a feature of the invention that conventional cyclone separator assemblies can be upgraded to utilise the invention. This can be achieved by the relatively simple expedient of replacing the internal dividing plates within the pressure vessel which have bores for receiving respective ends of conventional separator tubes with dividing plates adapted to receive the non concentric separator tubes of the invention, such that more tubes can then be packed within the space available within the pressure vessel, thereby increasing overall efficiency.

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Claims

1. A cyclone separator comprising or including a pressure vessel (10) containing one or more cyclone separator tubes (4,33), the or each tube having an inlet end (21) adjacent an overflow outlet end (22), an underflow outlet end and a concentric interior therebetween, CHARACTERISED IN THAT the outer wall of the or each tube is non-concentric with the interior thereof, at least at the inlet end of the tube, the tube walls being relatively thick in this region 0 compared to the thickness of the tube walls diametrically opposite thereto.

2. A cyclone separator assembly (10,12) comprising or is including a spacer (29,39) for fitting over or around one end of the or each separator tube (4,33) to provide localised mechanical support between adjacent wall members (14,15) of the pressure vessel (10) through at least one of which the or each tube extends, thereby permitting axial movement of the or each tube whilst retaining the mechanical integrity of said one or each wall member around said location.

3. A cyclone separator assembly according to Claim 2 wherein the spacer comprises a substantially annular collar (29) for surrounding the overflow outlet end (22) of the 17 separator tube (4), the collar including an exit duct (26) for the separated fluid.

4. A cyclone separator assembly according to Claim 3 wherein the annular collar (29) includes a shoulder portion (30) for supporting a local portion of the pressure vessel wall (15) through which the overflow exit end (22) of the separator tube (4,33) extends.

5. A cyclone separator assembly according to Plaim 2 in which the spacer (39) comprises a pair of spacer bars (40,41) connected together by a web (38), from a central portion of which extends a stud (42) adapted to be received within a correspondingly shaped bore in the overflow exit end (22) of a separator tube within the cyclone separator assembly.

6. A cyclone separator assembly according to claim 5 further characterised in that the overflow exit end (22) of the or each separator tube is in the form of a hollow spigot (24) coaxial with the major axis of the interior of the tube (33).

7. A cyclone separator assembly according to claim 6 in which the spigot (24) includes an exit duct (26) in the sidewall thereof.

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8. A cyclone separator assembly according to any one of claims 5 to 7 further characterised in that the free end of the overflow exit end of the or each separator tube includes a slot (32,37) co-operable with a formation (31,38) on the spacer (29,39) to thereby prevent relative rotation therebetween about the major axis of the tube.

9. A cyclone separator tube having an inlet end (5), an underflow outlet end (34) and a concentric interior there between, CHARACTERISED IN THAT the outer walls of the tube 0 are non-concentric with the interior thereof, at least at the inlet end of the tube, the tube walls (5) being relatively thick in this region compared to the thickness of the tube walls (6) diametrically opposite thereto.

is

10. A cyclone separator tube according to claim 9 further characterised in that the overflow exit end is in the form of a hollow spigot (24) coaxial with the major axis of the interior of the tube (4,33).

11. A cyclone separator tube according to claim 10 further characterised in that the spigot includes an exit duct (26) in the sidewall thereof.

12. A cyclone separator tube according to claim 10 or claim 11 further characterised in that the free end of the spigot (24) includes a slot (25) adapted to, in combination 19 with formations (31,38,42) on or in a cyclone separator assembly into which the cyclone separator tube is to be fitted, prevent rotation of the tube about its major axis.

13. A method of increasing the packing density of cyclone separation tubes within conventional cyclone separation assemblies by replacing internal dividing walls components adapted to receive a number of conventional cyclone separator tubes with corresponding components adapted to 10 receive a greater number of cyclone separator tubes according to Claims 9 to 12 and dimensionally compatible accessories therefor, to thereby increase the packing density of tubes within the pressure vessel. is

14. A method according to Claim 13 wherein adjacent cyclone separator tubes as claimed in Claims 9 to 12 are packed within the cyclone separator assembly such that the relatively thick-walled inlet end of at least one tube is disposed substantially next to the thinnest wall of an 20 adjacent tube, to thereby maximise the packing density of at least two said tubes within the cyclone separator assembly.

15. A method according to Claims 13 or 14 further 25 characterised in that substantially all of the cyclone separator tubes within the cyclone separator assembly are positioned to maximise the available packing density within the assembly.

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