Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
  • B04C11/00—Accessories, e.g. safety or control devices, not otherwise provided for, e.g. regulators, valves in inlet or overflow ducting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0217—Separation of non-miscible liquids by centrifugal force
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/04—Breaking emulsions
  • B01D17/047—Breaking emulsions with separation aids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
  • B04C5/00—Apparatus in which the axial direction of the vortex is reversed
  • B04C5/08—Vortex chamber constructions
  • B04C5/081—Shapes or dimensions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
  • B04C5/00—Apparatus in which the axial direction of the vortex is reversed
  • B04C5/12—Construction of the overflow ducting, e.g. diffusing or spiral exits
  • B04C5/13—Construction of the overflow ducting, e.g. diffusing or spiral exits formed as a vortex finder and extending into the vortex chamber; Discharge from vortex finder otherwise than at the top of the cyclone; Devices for controlling the overflow
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
  • B04C—APPARATUS USING FREE VORTEX FLOW, e.g. CYCLONES
  • B04C5/00—Apparatus in which the axial direction of the vortex is reversed
  • B04C5/22—Apparatus in which the axial direction of the vortex is reversed with cleaning means
  • B04C5/23—Apparatus in which the axial direction of the vortex is reversed with cleaning means using liquids

Definitions

• This invention relates to a cyclone separator.
• United States Patent 4,237,006 (Coleman et al) describes a cyclone separator having a separating chamber having first, second and third contiguous cylindrical portions arranged in that order, the first cylindrical portion being of greater diameter than the second cylindrical portion and the third cylindrical portion being of lesser diameter than the second cylindrical portion, the first cylindrical portion having an overflow outlet at the end thereof opposite to said second cylindrical portion and a tangentially directed feed inlet, the separator being adapted to separate liquids one from the other in a mixture when infed into said separating chamber via said feed inlet, one said liquid emerging from said overflow outlet and the other passing through said third cylindrical portion in the direction away from said second cylindrical portion to emerge from an underflow outlet of the separator at the end of said separating chamber remote from said first cylindrical portion.
• the above separator is intended specifically, but not exclusively, for separating oil from water, the oil in use emerging from the overflow outlet and the water from said third cylindrical portion.
• the aforementioned cylindrical portions may not be truly cylindrical, in the sense that they do not need in all cases to present a side surface which is linear in cross-section and parallel to the axis thereof.
• United States Patent 4,237,006 describes arrangements wherein the first cylindrical portion has a frustoconical section adjacent the second cylindrical portion and which provides a taper between the largest diameter of the first cylindrical portion and the diameter of the second cylindrical portion where this meets the first cylindrical portion.
• the aforementioned patent specification describes arrangements wherein a similar section of frustoconical form is provided to cause a tapering in the diameter of the second cylindrical portion from a largest diameter of the second cylindrical portion to the diameter of the third cylindrical portion.
• the second cylindrical portion exhibits a constant taper over its whole length.
• d 0 is the internal diameter of said overflow outlet
• d 1 is the diameter of the first portion
• d 2 is the diameter of the second portion
• d 3 is the diameter of the third portion
• 1 2 is the length of the second portion
• a 1 is the total cross-sectional area of all the feed inlets measured at the points of entry into the separating chamber normal to the inlet flow.
• the overflow outlet may present a stepped bore with a first bore portion adjacent the first cylindrical portion being of greater diameter than a second bore portion thereof further from the first cylindrical portion.
• the first bore portion may have a diameter d 0 in the range 0.0035 ⁇ d 0 /d 1 ⁇ 1 and the second bore portion may have a diameter d 5 in the range 0.0035 ⁇ d 5 /d 1 ⁇ d 0 /d 1 .
• the invention provides an improved cyclone separator of the first above described kind wherein said overflow outlet presents the above mentioned stepped bore and wherein the stepped bore is characterised by the provision of a passageway leading from the said first bore portion to the exterior of the separator.
• the bore portions are conveniently of circular cross section but may have any convenient cross section.
• valve means is provided selectively operable to permit flow from said passageway.
• Means may be provided sensitive to flow through the separator to control said valve means to permit said flow from said passageway on occurrence of flow through said second bore portion falling below a pre-selected rate. The flow may be measured by means positioned to be sensitive to flow in or from the second bore portion or by means positioned to be sensitive to flow in or through the first bore portion.
• the valve means may also be controlled to be operated by means responsive to the ratio of quantities of the liquid components in the liquid mixture to be separated whereby to open said valve means and permit flow from said passageway under the condition where the ratio exceeds a predetermined magnitude.
• the said valve may be opened under the condition where the oil content in emitted oil-water mixture exceeds, say, one-half percent.
• means is provided operable to connect said passageway for flow of liquid thereinto and back into the separating chamber via said first bore portion, to facilitate clearing of blockages in the overflow outlet.
• Figure 1 is a cutaway perspective view of a cyclone separator constructed in accordance with the present invention
• Figure 2 is an enlarged axial cross-sectional view of the overflow outlet of the separator of Figure 1;
• Figure 3 is an enlarged fragmentary cross-sectional view of the overflow outlet of the separator of Figure 1.
• the separator 10 shown in Figure 1 has a separating chamber 25 having first, second and third cylindrical portions 12, 14 and 16 coaxially arranged in that order. These cylindrical portions are generally similar to the corresponding first, second and third cylindrical portions of the separating chamber of the cyclone separator described in the aforementioned United States patent 4,237,006, the disclosures of which are hereby incorporated into the present specification to form part thereof.
• the first cylindrical portion 12 has two feect pipes 26, 28 associated therewith, these being arranged to feed tangentially into the cylindrical portion 12 via respective inlet apertures of which only one aperture, namely aperture 30 associated with pipe 26, is visible in the drawing.
• the two feed inlet apertures are diametrically arranged one relative to the other and positioned close to the end of portion 12 remote from portion 14.
• the end of portion 12 remote from portion 14 also has a circular outlet opening 32 which leads to an overflow outlet pipe 34.
• a tapered part 12a of the separating chamber is positioned between the first and second portions 12, 14 towards the second cylindrical portion 14. As explained in United States Patent 4,237,006 however, such tapered section is not essential.
• the second cylindrical portion 14 exhibits a taper over its length, tapering from a diameter at the end adjacent part 12a equal to the diameter of part 12a at the junction between the two portions to a somewhat lesser dimension at its opposite end.
• Cylindrical portion 16 is a constant diameter equal to the minimum diameter of portion 14.
• the length 1. of portion 12, its diameter d 1 , the taper angle " ⁇ " of the tapered part 12a, the internal diameter d 0 of the outlet pipe 34 at its greatest diameter end, the length and diameter 1 2 , d 2 of the second portion 14, the taper angle " ⁇ " of the second portion 14 and the length 1 3 and diameter d 3 of the third cylindrical portion, as well as the total area A i of the two feed inlet apertures 30 may all be selected in accordance with the parameters mentioned in United States patent 4,237,006 although the outlet diameter d 0 need not constrained to be within limits as described therein, nor need the length 1 2 be selected to not exceed the maximum limit of 25 for the ratio 1 2 / d 2 .
• portion 18 may be added to the separating chamber 25, this portion being designated by reference numeral 18 in the figure.
• Portion 18 has a part 18a adjacent portion 16 which is of frustocpnical configuration, tapering from a maximum diameter equal to d 3 at its end closest to and adjoining to the outlet end of cylindrical portion 16, to a diameter d. at its outlet end.
• fourth portion 18 includes an outlet pipe 18b which is of internal diameter d 4 , this leading to an underflow outlet 23.
• the angle " ⁇ " being the conicity or half-angle of the frustoconical surface of part 18a is about 45°, although angles in the range 30 to 60 are generally satisfactory.
• the ratio d 4 /d 3 be in the range 1:3 to 2:3.
• the length of part 18a is not critical to the invention and in any event is normally fixed by the selection of the aforementioned ratio of diameters d 4 to d 3 .
• the length of the pipe 18b has not been found to be important to the operation of the invention.
• part 18a is shown as having a truly frustoconical cross-sectional form (that is to say it is shown as having a side surface which exhibits a linear sloping configuration relative to the axis of the portion when viewed in section) this is not essential.
• the part 18 may have a conicity angle which varies along the length thereof such as either increasing or decreasing the direction from the greater diameter end to the lesser diameter end thereof. In any event, it is preferred that the length of the part 18 be roughly the same as the maximum diameter thereof.
• liquid to be separated is admitted tangentially to the interior of cylindrical portion 12 via feed pipes 26, 28, the denser component of the liquid then travelling lengthwise through the separator to emerge from outlet 23 of pipe 18b, whilst the lighter component emerges from pipe 34.
• the tapered part 12a may be of length about 160mm.
• the first, second and third cylindrical portions may also in such a case have diameters as follows: first cylindrical portion, diameter d 1 , 116mm, second cylindrical portion 14; diameter 58mm at diameter d 2 tapering to 27mm at diameter d 3 , cylindrical portion 16, diameter d 3 , 27mm.
• the feed inlets 30 may have diameters of 20mm with the overflow outlet 32 being of diameter 2.5mm.
• Figure 2 shows outlet pipe 34 in more detail.
• the pipe has a stepped interior bore leading from outlet opening 32. More particularly, the bore has a first portion 34' adjacent outlet 32 of diameter equal to the diameter of outlet 32 and a second portion 34" away from outlet 32 of lesser diameter than bore portion 34'.
• Bore portion 34' may be of diameter d in the range 0.125 to 0.625 preferably 0.17 to 0.47 times the diameter d. of portion 12 of the separating chamber 25.
• Bore portion 34" may be of diameter d 5 0.015 to 0.05 preferably 0.025 to 0.035 times the diameter d 1 of portion 12 of the separating chamber 25.
• the first bore portion may have a diameter d 0 anywhere in the range 0.0035 ⁇ d 0 /d 1 ⁇ 1 and the second bore portion may have a diameter d 5 in the range 0.0035 ⁇ d 5 /d 1 ⁇ d 0 /d 1 .
• the length of the bore portion 34" is not important. It has been determined that the efficiency tends to decrease slightly as the length L, of the bore portion 34' is increased. With increasing length L, a point is eventually reached where the operation of the cyclone becomes unstable. It has also been found that the smaller the diameter d 0 , the larger can be the length L before unstable operation occurs. Generally the ratio L/d 0 may be up to 10 at least for ratios d 0 /d 2 ⁇ 0.31.
• the split ratio F is defined as the ratio
• the efficiency was determined by measuring the concentration C 1 of oil in the inlet mixture and the concentration of oil C 2 in the water delivered from the underflow outlet of the separator so that efficiency E is defined as the ratio
• outlet pipe 34 also has a passageway 51 formed through the side wall thereof and providing communication between the bore portion 34' and the exterior of the outlet pipe 34.
• This passageway may for example have a diameter in the range 0.05 to 0.10 of the diameter d 1 .
• Passageway 51 provides communication, via an exterior pipe 55 to a valve 53.
• valve 53 may be closed so that overflow passes from the outlet 32 through the bore portion 34' and thence through the bore portion 34".
• liquid may be admitted into the bore portion 34' via the pipe 55 and passageway 51 by connecting the outlet of the valve 53 to suitable high pressure liquid supply to permit liquid flow back through the passageway 34' through the outlet 32 and into the separating chamber of the separator.
• the supply of high pressure liquid may be the supply of liquid to be separated which may, for example, be temporarily diverted from inflow into the inlet pipes 26, 28 during the time of admission of the liquid through the passageway 51 into the outlet pipe 34. It is possible, in an alternative embodiment of the invention (not shown), to provide
• flow sensing means operable to sense the flow from the outlet pipe 34 and to automatically operate the valve 53 to divert the incoming liquid flow which is normally passed to the inlet pipes 26,28 to flow through passageway 51 to the bore portion 34' for blockage clearing.
• the invention is not confined to arrangements where there is a single passageway 51.
• two or more such passageways of various diameters may be provided. These may be selectively operable in accordance with the measured oil content or, for example, one may be used for diverting outflow under the high oil content condition and another used for clearance of blockages.
• Operation of the separator of the invention may be facilitated by arranging for entrainment of a suitable emulsion breaker into the incoming water-oil mixture.
• the entrainment may be effected by use of known dosing techniques such as injecting an emulsion breaker into the incoming liquid prior to feeding to the feed pipes 26, 28.
• Emulsion breakers or surfactants, are thought to be effective in facilitating separation of oily water because the oil is naturally present in the form of droplets which, by surface tension effects, are resistant to separating movement under centrifugal action in the separator.
• emulsion breakers act to reduce such surface tension effects to render the droplets more mobile under centrifugal forces.
• the concentration of added emulsion breaker may be selected to be in the range 2 to 100 p.p.m.
• the effectiveness of the emulsion breaker is dependent on the extent of kinetic mixing which occurs and the residence time in the mixture prior to admission to the separator. Good mixing and adequate residence time are necessary for best results. Generally, however, the described method of injection into the incoming liquid has been found satisfactory.
• Example 1 was repeated but with the injection into the oil-water mixture prior to admission to the separator of 30 p.p.m. of a commercial emulsion breaker type sold under the name Applied Chemicals type 8980. Injection was made into a pipe leading to the separator inlet by use of a piston pump from a reservoir of the emulsion breaker. The separated water at the underflow outlet of the separator was found to have a concentration of 14 p.p.m. oil.

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• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Geometry (AREA)
• Cyclones (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=3770302

Family Applications (1)

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• 1984
  • 1984-08-29 BR BR8407045A patent/BR8407045A/pt unknown
  • 1984-08-29 EP EP84903160A patent/EP0158641A1/de not_active Withdrawn
  • 1984-08-29 JP JP59503245A patent/JPS61500009A/ja active Pending
  • 1984-08-29 GB GB08510248A patent/GB2158372B/en not_active Expired
  • 1984-08-29 WO PCT/AU1984/000164 patent/WO1985000990A1/en not_active Application Discontinuation
  • 1984-08-29 NL NL8420224A patent/NL8420224A/nl unknown
• 1985
  • 1985-04-30 OA OA58582A patent/OA08005A/xx unknown
  • 1985-05-01 DK DK195785A patent/DK195785D0/da not_active Application Discontinuation

Non-Patent Citations (1)

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