WO2012123489A1 - Method and apparatus for separating solids from a liquid suspension thereof - Google Patents

Method and apparatus for separating solids from a liquid suspension thereof Download PDF

Info

Publication number
WO2012123489A1
WO2012123489A1 PCT/EP2012/054451 EP2012054451W WO2012123489A1 WO 2012123489 A1 WO2012123489 A1 WO 2012123489A1 EP 2012054451 W EP2012054451 W EP 2012054451W WO 2012123489 A1 WO2012123489 A1 WO 2012123489A1
Authority
WO
WIPO (PCT)
Prior art keywords
vessel
liquid
solids
wall
peripheral wall
Prior art date
Application number
PCT/EP2012/054451
Other languages
French (fr)
Inventor
Anthony Convery
Original Assignee
Cde Global Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Cde Global Limited filed Critical Cde Global Limited
Publication of WO2012123489A1 publication Critical patent/WO2012123489A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2444—Discharge mechanisms for the classified liquid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/01—Separation of suspended solid particles from liquids by sedimentation using flocculating agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/003—Sedimentation tanks provided with a plurality of compartments separated by a partition wall
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/24—Feed or discharge mechanisms for settling tanks
    • B01D21/2405—Feed mechanisms for settling tanks
    • B01D21/2411—Feed mechanisms for settling tanks having a tangential inlet
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/26—Separation of sediment aided by centrifugal force or centripetal force
    • B01D21/267—Separation of sediment aided by centrifugal force or centripetal force by using a cyclone
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D21/00—Separation of suspended solid particles from liquids by sedimentation
    • B01D21/28—Mechanical auxiliary equipment for acceleration of sedimentation, e.g. by vibrators or the like
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/008—Control or steering systems not provided for elsewhere in subclass C02F
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/38—Treatment of water, waste water, or sewage by centrifugal separation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
    • C02F1/56—Macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/125—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using screw filters
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/127—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering by centrifugation
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F2001/007—Processes including a sedimentation step
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2201/00—Apparatus for treatment of water, waste water or sewage
    • C02F2201/008—Mobile apparatus and plants, e.g. mounted on a vehicle

Definitions

  • the present invention relates to a method and apparatus for separating solids from a liquid suspension thereof and in particular, but not exclusively, to a method and apparatus for separating fines (i.e. solids held in suspension) from waste water downstream of a sand washing apparatus.
  • Sand is typically washed with water during extraction to remove contaminants from the sand.
  • Sand is typically contaminated with solid impurities, such as finely divided clay and other fines. These impurities are removed from the sand by a washing process using water and the waste water, containing the impurities, is removed from the sand, typically in a cyclone separator or similar dewatering apparatus.
  • the waste water carries the impurities from the sand in suspension.
  • these impurities must be removed from the water. This is typically done by adding a flocculating agent to which the fines bind to bring them out of suspension, and passing the water into a settling tank wherein the fines are able to settle out under the action of gravity.
  • Flocculation is a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters, typically by binding to a flocculant. This settling process may take some time and requires a relatively large settling tank to deal with the volume of water to be treated, increasing the amount of water required for a sand washing process and/or placing a limit on the speed of the overall process.
  • the collected concentrated solids can be removed from the lower region of the settlement tank for subsequent dewatering and disposal.
  • the cleaned or clarified water is removed from an upper region of the settlement tank to be re-used in the washing process.
  • a method of separating solids from a liquid suspension thereof comprising the steps of adding a flocculating agent to said liquid having solids suspended therein, introducing said liquid into a vessel having a curved peripheral wall, imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, removing said liquid from an upper region of the vessel and removing said collected solids from a lower region of the vessel.
  • the present invention enables the mixture of solids suspended in a liquid to be separated into a clarified liquid stream for re-use and a concentrated solids stream which can be subsequently dewatered in downstream processes.
  • the step of imparting rotation to the liquid may comprise stirring the liquid within the vessel by means of a stirring device, such as one or more paddles or vanes, adapted to be moved in a rotary fashion within the vessel.
  • a stirring device such as one or more paddles or vanes
  • the step of imparting rotation to the liquid is controlled so that the flocculated solids are moved to the curved peripheral wall of the vessel by centrifugal action without breaking up the flocculated solids.
  • the liquid is constrained to move through an annular space within the vessel as it enters the vessel such that the liquid follows a substantially downwardly extending spiral path through said annular space.
  • said annular space is defined between concentric cylindrical surfaces within the vessel.
  • the method may comprise the further step of dewatering the collected solids downstream of said vessel, preferably by means of a centrifugal separator or a screw conveyor or similar.
  • an apparatus for separating solids from a liquid suspension thereof comprising a vessel having a curved peripheral wall, means for adding a flocculating agent to said liquid having solids suspended therein, means for introducing said liquid into said vessel, means for imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, means for removing said liquid from an upper region of the vessel and means for removing said collected solids from a lower region of the vessel.
  • Said means for introducing said liquid into the vessel may comprise a tangentially directed inlet such that said liquid is introduced into said vessel in a tangential direction to impart rotation to said liquid.
  • said means for imparting rotation to the liquid comprises a stirring device, such as one or more paddles or vanes, adapted to be moved in a rotary fashion within the vessel.
  • said rotation imparting means are controlled and/or adapted so that the flocculated solids are moved to the curved peripheral wall of the vessel by centrifugal action without breaking up the flocculated solids.
  • At least an upper region of the vessel may comprise a substantially cylindrical outer wall defining said curved peripheral wall.
  • a substantially cylindrical inner wall may be provided within the vessel coaxially arranged within said outer wall to define an annular space between said inner and outer walls, said means for introducing said liquid into the vessel being arranged to introduce said liquid into said annular space, preferably adjacent an upper end of said inner and outer walls.
  • the upper end of the inner walls terminates below the upper end of the outer wall.
  • the outer wall of the vessel may be connected to the inner wall by means of an annular plate extending between said outer and inner walls adjacent an upper end of the inner and outer walls to form the bottom of a weir defined between the inner and outer walls adjacent an upper end of the vessel.
  • Said means for removing water from the vessel may comprise an outlet communicating with said weir for draining water from the weir.
  • said means for introducing said liquid into the vessel comprises an inlet located in the outer wall below said annular plate.
  • Said stirring device may be provided in said annular space between said outer an inner walls of the vessel.
  • said stirring device comprises one or more paddles provided within or extending into said annular space between said inner and outer walls, said paddles being mounted to rotate around said annular space about a rotational axis arranged coaxially with the cylindrical inner and outer walls of the vessel.
  • said paddles are driven by means of a motor, such as an electric or hydraulic motor.
  • a speed control means is provided for controlling the speed of movement of said paddles so that the flocculated solids are urged towards the outer wall of the vessel without substantial breaking up of the flocculated solids due to the action of the paddles.
  • the lower region of the vessel may comprise a substantially conical solids collection region, said means for removing said solids from the vessel comprising an outlet provided a lower end of said solids collection region.
  • the lower region of the vessel be any other shape, for example tubular, and may comprise a flat, dished or domed base.
  • the apparatus may further comprise dewatering means for dewatering the collected solids downstream of said vessel.
  • Said dewatering means may comprise a centrifugal separator or a screw conveyor or similar.
  • FIG. 1 is a schematic view of the apparatus for separating solids from a liquid suspension in accordance with an embodiment of the present invention
  • Figure 2 is a front view of the solids separation vessel of the apparatus of Figure 1 ;
  • Figure 3 is a perspective view of an upper part of the vessel of Figure 2;
  • Figure 4 is a schematic sectional perspective view of the vessel of Figure 2;
  • an apparatus for separating solids from a liquid suspension in accordance with an embodiment of the present invention comprises an polyelectrolyte dosing device 10 for adding a flocculating agent to waste water 12 containing solid contaminants in suspension, a solids separation vessel 20 for separating flocculated solids from the water, a centrifuge separator 30 for removing water from the solids downstream of the solids separation vessel 20, a screw conveyor 40 for solids discharge downstream of the centrifuge separator 40, a clarified water storage tank 50 for receiving clarified water from the solids separating vessel 20 and the centrifuge separator 30 and an electrical control system.
  • the solids separation vessel 20 consisting of outer and inner concentric vertically arranged cylinders 100,102.
  • a lower portion of the vessel 20 is defined by a conical section 104, the lower end of the outer cylinder 100 adjoining the upper end of said conical section 104.
  • the conical lower section 104 of the vessel 20 defines a closed bottom having a centrally located flanged solids outlet 106.
  • the inner cylinder 102 is open at both ends.
  • the top of the inner cylinder 102 is lower than the top of the outer cylinder 100.
  • the bottom of the inner cylinder 102 is higher than the bottom of the outer cylinder 100.
  • the outer cylinder 100 is connected to the inner cylinder 102 by means of an annular plate 108, which forms the bottom of a weir section 1 10 which is located towards the top of the vessel 20 for receiving clarified water.
  • a flanged water outlet 1 12 is located on the outer wall of the weir section 1 10.
  • the annular plate 108 may be inclined downwardly towards the water outlet 1 12.
  • a flanged waste water inlet 1 14 is provided in the outer cylinder 100, said inlet 1 14 extending tangentially directly below the weir section 1 10 to direct water entering the vessel 20 in a tangential direction into the annular space 105 defined between the inner and outer cylinders 100,102.
  • a centrally mounted motor driven paddle assembly consisting of two diametrically opposed rectangular paddles 1 16,1 18, is mounted to rotate within the annular space defined between the inner and outer cylinders, driven by an electric motor 120.
  • washing process waste water 12 is dosed with polyelectrolyte flocculent upstream of the solids separation vessel 20 by means of the dosing device 10.
  • the dosing device 10 may dilute and mix the flocculant into water to create a flocculant solution that can be mixed into the waste water 12.
  • the waste water 12 and flocculant solution may be mixed in a mixing device 1 1 , such as a baffled chamber, before the flocculated waste water enters the annular space 105 defined between the inner and outer cylinders 100,102 through the water inlet 1 14.
  • the flow enters the vessel tangentially at the top of said annular space 105 below the weir section 1 10 and flows a spiral path as it circulates around and down said annular space 105.
  • the circulatory velocity is controlled and regulated by the speed of the rotating paddles 1 16,1 18 under the control of the motor 120.
  • the circulatory velocity is controlled so that the flocculated solids are moved to the outer wall of the vessel 20 under the action of centrifugal force without being broken up by such motion.
  • the use of the rotating paddle assembly enables sufficiently accurate control of such circulatory velocity to achieve such objective, enabling the solids to be effectively brought of suspension and separated from the water much more rapidly than can be achieved with known settling tank arrangements.
  • sufficient control of the circulatory velocity may be achieved by virtue of the speed and direction at which the waste water is introduced into the annular space 105 between the inner and outer cylinders 100,102, obviating the need for the rotating paddle assembly.
  • the circulatory velocity may be controlled to achieve a centrifugal acceleration of between 1 g and 3g.
  • a typical hydrocyclone has a centrifugal acceleration of between 15g and 70g
  • a typical centrifuge decanter separator such as that used in waste water solids separation
  • the flocculated solids within the flow are subjected to a centrifugal force as they rotate around the annular space 105 between the outer and inner cylinders 100,102, resulting in classification/stratification of the slurry, with the solids migrating to the outer wall of the vessel 20 to settle in a lower region of the vessel 20.
  • the solids rich slurry at the outer wall is drawn radially inwards along the wall of the conical lower region 104 of the vessel 20 and exits through the central outlet 106.
  • the clarified water enters the cylindrical space 122 defined within the inner cylinder 102, through its base.
  • the clarified water rises through said cylindrical space 122 within the inner cylinder 102 and overflows over the upper end of the inner cylinder 102 into the weir section 1 10 before being discharged from the weir section 1 10 through the water outlet 1 12 such that the water can be reused.
  • the apparatus may provide a clarified water outflow from the water outlet having a solids content of less than 0.02% solids by weight while the solids rich slurry delivered out of the central outlet 106 may have a solids content of around 20% to 25% solids by weight.
  • the apparatus in accordance with the present invention may provide a compact and readily transportable complete waste water treatment system for use in aggregate and mineral washing applications (as well as a variety of process water treatment applications in a variety of sectors where there is a requirement to remove fine particle solids). It may be suitable for use in temporary wash plants which relocate regularly. It may also offer a cost effective option for export and shipping worldwide in permanent static installations when compared to alternative technologies.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Organic Chemistry (AREA)
  • Physical Water Treatments (AREA)
  • Centrifugal Separators (AREA)
  • Separation Of Suspended Particles By Flocculating Agents (AREA)

Abstract

A method of separating solids from a liquid suspension thereof comprising the steps of adding a flocculating agent to said liquid having solids suspended therein, introducing said liquid into a vessel having a curved peripheral wall, imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, removing said liquid from an upper region of the vessel and removing said collected solids from a lower region of the vessel.

Description

Method and Apparatus for Separating Solids
from a Liquid Suspension Thereof
The present invention relates to a method and apparatus for separating solids from a liquid suspension thereof and in particular, but not exclusively, to a method and apparatus for separating fines (i.e. solids held in suspension) from waste water downstream of a sand washing apparatus.
Sand is typically washed with water during extraction to remove contaminants from the sand. Sand is typically contaminated with solid impurities, such as finely divided clay and other fines. These impurities are removed from the sand by a washing process using water and the waste water, containing the impurities, is removed from the sand, typically in a cyclone separator or similar dewatering apparatus. The waste water carries the impurities from the sand in suspension.
Before the waste water can be re-used, these impurities must be removed from the water. This is typically done by adding a flocculating agent to which the fines bind to bring them out of suspension, and passing the water into a settling tank wherein the fines are able to settle out under the action of gravity. Flocculation is a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters, typically by binding to a flocculant. This settling process may take some time and requires a relatively large settling tank to deal with the volume of water to be treated, increasing the amount of water required for a sand washing process and/or placing a limit on the speed of the overall process. The collected concentrated solids can be removed from the lower region of the settlement tank for subsequent dewatering and disposal. The cleaned or clarified water is removed from an upper region of the settlement tank to be re-used in the washing process. According to a first aspect of the present invention there is provided a method of separating solids from a liquid suspension thereof comprising the steps of adding a flocculating agent to said liquid having solids suspended therein, introducing said liquid into a vessel having a curved peripheral wall, imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, removing said liquid from an upper region of the vessel and removing said collected solids from a lower region of the vessel.
Thus the present invention enables the mixture of solids suspended in a liquid to be separated into a clarified liquid stream for re-use and a concentrated solids stream which can be subsequently dewatered in downstream processes.
Preferably said liquid is removed from a substantially central region of said upper region of the vessel. The step of imparting rotation to the liquid may comprise stirring the liquid within the vessel by means of a stirring device, such as one or more paddles or vanes, adapted to be moved in a rotary fashion within the vessel. Preferably the step of imparting rotation to the liquid is controlled so that the flocculated solids are moved to the curved peripheral wall of the vessel by centrifugal action without breaking up the flocculated solids.
Preferably the liquid is constrained to move through an annular space within the vessel as it enters the vessel such that the liquid follows a substantially downwardly extending spiral path through said annular space. Preferably said annular space is defined between concentric cylindrical surfaces within the vessel.
The method may comprise the further step of dewatering the collected solids downstream of said vessel, preferably by means of a centrifugal separator or a screw conveyor or similar.
According to a further aspect of the present invention there is provided an apparatus for separating solids from a liquid suspension thereof comprising a vessel having a curved peripheral wall, means for adding a flocculating agent to said liquid having solids suspended therein, means for introducing said liquid into said vessel, means for imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, means for removing said liquid from an upper region of the vessel and means for removing said collected solids from a lower region of the vessel.
Said means for introducing said liquid into the vessel may comprise a tangentially directed inlet such that said liquid is introduced into said vessel in a tangential direction to impart rotation to said liquid.
Preferably said means for imparting rotation to the liquid comprises a stirring device, such as one or more paddles or vanes, adapted to be moved in a rotary fashion within the vessel. Preferably said rotation imparting means are controlled and/or adapted so that the flocculated solids are moved to the curved peripheral wall of the vessel by centrifugal action without breaking up the flocculated solids. At least an upper region of the vessel may comprise a substantially cylindrical outer wall defining said curved peripheral wall. A substantially cylindrical inner wall may be provided within the vessel coaxially arranged within said outer wall to define an annular space between said inner and outer walls, said means for introducing said liquid into the vessel being arranged to introduce said liquid into said annular space, preferably adjacent an upper end of said inner and outer walls. Preferably the upper end of the inner walls terminates below the upper end of the outer wall. The outer wall of the vessel may be connected to the inner wall by means of an annular plate extending between said outer and inner walls adjacent an upper end of the inner and outer walls to form the bottom of a weir defined between the inner and outer walls adjacent an upper end of the vessel. Said means for removing water from the vessel may comprise an outlet communicating with said weir for draining water from the weir. Preferably said means for introducing said liquid into the vessel comprises an inlet located in the outer wall below said annular plate.
Said stirring device may be provided in said annular space between said outer an inner walls of the vessel. In one embodiment said stirring device comprises one or more paddles provided within or extending into said annular space between said inner and outer walls, said paddles being mounted to rotate around said annular space about a rotational axis arranged coaxially with the cylindrical inner and outer walls of the vessel. Preferably said paddles are driven by means of a motor, such as an electric or hydraulic motor. Preferably a speed control means is provided for controlling the speed of movement of said paddles so that the flocculated solids are urged towards the outer wall of the vessel without substantial breaking up of the flocculated solids due to the action of the paddles.
The lower region of the vessel may comprise a substantially conical solids collection region, said means for removing said solids from the vessel comprising an outlet provided a lower end of said solids collection region. However, it is envisaged that the lower region of the vessel be any other shape, for example tubular, and may comprise a flat, dished or domed base.
The apparatus may further comprise dewatering means for dewatering the collected solids downstream of said vessel. Said dewatering means may comprise a centrifugal separator or a screw conveyor or similar.
An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which :- Figure 1 is a schematic view of the apparatus for separating solids from a liquid suspension in accordance with an embodiment of the present invention;
Figure 2 is a front view of the solids separation vessel of the apparatus of Figure 1 ; Figure 3 is a perspective view of an upper part of the vessel of Figure 2; Figure 4 is a schematic sectional perspective view of the vessel of Figure 2;
As shown in Figure 1 , an apparatus for separating solids from a liquid suspension in accordance with an embodiment of the present invention comprises an polyelectrolyte dosing device 10 for adding a flocculating agent to waste water 12 containing solid contaminants in suspension, a solids separation vessel 20 for separating flocculated solids from the water, a centrifuge separator 30 for removing water from the solids downstream of the solids separation vessel 20, a screw conveyor 40 for solids discharge downstream of the centrifuge separator 40, a clarified water storage tank 50 for receiving clarified water from the solids separating vessel 20 and the centrifuge separator 30 and an electrical control system.
As shown in Figures 2 to 4, the solids separation vessel 20 consisting of outer and inner concentric vertically arranged cylinders 100,102. A lower portion of the vessel 20 is defined by a conical section 104, the lower end of the outer cylinder 100 adjoining the upper end of said conical section 104. The conical lower section 104 of the vessel 20 defines a closed bottom having a centrally located flanged solids outlet 106. The inner cylinder 102 is open at both ends. The top of the inner cylinder 102 is lower than the top of the outer cylinder 100. The bottom of the inner cylinder 102 is higher than the bottom of the outer cylinder 100. The outer cylinder 100 is connected to the inner cylinder 102 by means of an annular plate 108, which forms the bottom of a weir section 1 10 which is located towards the top of the vessel 20 for receiving clarified water. A flanged water outlet 1 12 is located on the outer wall of the weir section 1 10. The annular plate 108 may be inclined downwardly towards the water outlet 1 12. A flanged waste water inlet 1 14 is provided in the outer cylinder 100, said inlet 1 14 extending tangentially directly below the weir section 1 10 to direct water entering the vessel 20 in a tangential direction into the annular space 105 defined between the inner and outer cylinders 100,102. As can be best seen from Figure 4, a centrally mounted motor driven paddle assembly, consisting of two diametrically opposed rectangular paddles 1 16,1 18, is mounted to rotate within the annular space defined between the inner and outer cylinders, driven by an electric motor 120.
In use, washing process waste water 12 is dosed with polyelectrolyte flocculent upstream of the solids separation vessel 20 by means of the dosing device 10. The dosing device 10 may dilute and mix the flocculant into water to create a flocculant solution that can be mixed into the waste water 12. The waste water 12 and flocculant solution may be mixed in a mixing device 1 1 , such as a baffled chamber, before the flocculated waste water enters the annular space 105 defined between the inner and outer cylinders 100,102 through the water inlet 1 14. The flow enters the vessel tangentially at the top of said annular space 105 below the weir section 1 10 and flows a spiral path as it circulates around and down said annular space 105. The circulatory velocity is controlled and regulated by the speed of the rotating paddles 1 16,1 18 under the control of the motor 120. The circulatory velocity is controlled so that the flocculated solids are moved to the outer wall of the vessel 20 under the action of centrifugal force without being broken up by such motion. The use of the rotating paddle assembly enables sufficiently accurate control of such circulatory velocity to achieve such objective, enabling the solids to be effectively brought of suspension and separated from the water much more rapidly than can be achieved with known settling tank arrangements. However, it is envisaged that sufficient control of the circulatory velocity may be achieved by virtue of the speed and direction at which the waste water is introduced into the annular space 105 between the inner and outer cylinders 100,102, obviating the need for the rotating paddle assembly. The circulatory velocity may be controlled to achieve a centrifugal acceleration of between 1 g and 3g. For comparison, a typical hydrocyclone has a centrifugal acceleration of between 15g and 70g, whereas a typical centrifuge decanter separator, such as that used in waste water solids separation, has a centrifugal acceleration of between 2000g and 3000g. The flocculated solids within the flow are subjected to a centrifugal force as they rotate around the annular space 105 between the outer and inner cylinders 100,102, resulting in classification/stratification of the slurry, with the solids migrating to the outer wall of the vessel 20 to settle in a lower region of the vessel 20. The solids rich slurry at the outer wall is drawn radially inwards along the wall of the conical lower region 104 of the vessel 20 and exits through the central outlet 106. The clarified water enters the cylindrical space 122 defined within the inner cylinder 102, through its base. The clarified water rises through said cylindrical space 122 within the inner cylinder 102 and overflows over the upper end of the inner cylinder 102 into the weir section 1 10 before being discharged from the weir section 1 10 through the water outlet 1 12 such that the water can be reused.
For a waste water stream 12 having a solids content of approximately 5% solids by weight the apparatus may provide a clarified water outflow from the water outlet having a solids content of less than 0.02% solids by weight while the solids rich slurry delivered out of the central outlet 106 may have a solids content of around 20% to 25% solids by weight.
The apparatus in accordance with the present invention may provide a compact and readily transportable complete waste water treatment system for use in aggregate and mineral washing applications (as well as a variety of process water treatment applications in a variety of sectors where there is a requirement to remove fine particle solids). It may be suitable for use in temporary wash plants which relocate regularly. It may also offer a cost effective option for export and shipping worldwide in permanent static installations when compared to alternative technologies.
The invention is not limited to the embodiment(s) described herein but can be amended or modified without departing from the scope of the present invention.

Claims

Claims
1 . A method of separating solids from a liquid suspension thereof comprising the steps of adding a flocculating agent to said liquid having solids suspended therein, introducing said liquid into a vessel having a curved peripheral wall, imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, removing said liquid from an upper region of the vessel and removing said collected solids from a lower region of the vessel.
2. A method as claimed in claim 1 , wherein said liquid is removed from a substantially central region of said upper region of the vessel.
3. A method as claimed in claim 1 or claim 2, wherein the step of imparting rotation to the liquid comprises stirring the liquid within the vessel by means of a stirring device, such as one or more paddles or vanes, adapted to be moved in a rotary fashion within the vessel.
4. A method as claimed in claim 3, wherein the step of imparting rotation to the liquid is controlled so that the flocculated solids are moved to the curved peripheral wall of the vessel by centrifugal action without breaking up the flocculated solids.
5. A method as claimed in any preceding claim, wherein the liquid is constrained to move through an annular space within the vessel as it enters the vessel such that the liquid follows a substantially downwardly extending spiral path through said annular space.
6. A method as claimed in claim 5, wherein said annular space is defined between concentric cylindrical surfaces within the vessel.
7. A method as claimed in any preceding claim, comprising the further step of dewatering the collected solids downstream of said vessel, preferably by means of a centrifugal separator or a screw conveyor or similar.
8. An apparatus for separating solids from a liquid suspension thereof comprising a vessel having a curved peripheral wall, means for adding a flocculating agent to said liquid having solids suspended therein, means for introducing said liquid into said vessel, means for imparting a rotation to said liquid within the vessel whereby the flocculated solids are moved to said curved peripheral wall by centrifugal action, said solids moving down said curved peripheral wall to a lower region of the vessel under the action of gravity such that said solids collect in a lower region of said vessel, means for removing said liquid from an upper region of the vessel and means for removing said collected solids from a lower region of the vessel.
9. An apparatus as claimed in claim 8, wherein said means for introducing said liquid into the vessel comprises a tangentially directed inlet such that said liquid is introduced into said vessel in a tangential direction to impart rotation to said liquid.
10. An apparatus as claim 8 or claim 9, wherein said means for imparting rotation to the liquid comprises a stirring device adapted to be moved in a rotary fashion within the vessel.
1 1 . An apparatus as claimed in claim 10, wherein said stirring device comprises one or more paddles or vanes.
12. An apparatus as claimed in claim 10 or claim 1 1 , wherein said rotation imparting means are controlled and/or adapted so that the flocculated solids are moved to the curved peripheral wall of the vessel by centrifugal action without breaking up the flocculated solids.
13. An apparatus as claimed in any of claims 8 to 12, wherein at least an upper region of the vessel comprises a substantially cylindrical outer wall defining said curved peripheral wall.
14. An apparatus as claimed in claim 13, wherein a substantially cylindrical inner wall is provided within the vessel coaxially arranged within said outer wall to define an annular space between said inner and outer walls, said means for introducing said liquid into the vessel being arranged to introduce said liquid into said annular space.
15. An apparatus as claimed in claim 14, wherein said means for introducing said liquid into the vessel is arranged to introduce said liquid into said annular space adjacent an upper end of said inner and outer walls.
16. An apparatus as claimed in claim 14 or claim 15, wherein the upper end of the inner wall terminates below the upper end of the outer wall.
17. An apparatus as claimed in any of claims 14 to 16, wherein the outer wall of the vessel is connected to the inner wall by means of an annular plate extending between said outer and inner walls adjacent an upper end of the inner and outer walls to form the bottom of a weir defined between the inner and outer walls adjacent an upper end of the vessel.
18. An apparatus as claimed in claim 17, wherein said means for removing water from the vessel comprises an outlet communicating with said weir for draining water from the weir.
19. An apparatus as claimed in claim 18, wherein said means for introducing said liquid into the vessel comprises an inlet located in the outer wall below said annular plate.
20. An apparatus as claimed in any of claims 14 to 29, when dependent upon claim 10, wherein said stirring device is provided in said annular space between said outer an inner walls of the vessel.
21 . An apparatus as claimed in claim 20, wherein said stirring device comprises one or more paddles provided within or extending into said annular space between said inner and outer walls, said paddles being mounted to rotate around said annular space about a rotational axis arranged coaxially with the cylindrical inner and outer walls of the vessel.
22. An apparatus as claimed in claim 21 , wherein said paddles are driven by means of a motor.
23. An apparatus as claimed in claim 22, wherein said motor comprises an electric or hydraulic motor.
24. An apparatus as claimed in any of claims 21 to 23, wherein a speed control means is provided for controlling the speed of movement of said paddles so that the flocculated solids are urged towards the outer wall of the vessel without substantial breaking up of the flocculated solids due to the action of the paddles.
25. An apparatus as claimed in any of claims 8 to 24, wherein the lower region of the vessel comprises a substantially conical solids collection region, said means for removing said solids from the vessel comprising an outlet provided a lower end of said solids collection region.
26. An apparatus as claimed in any of claims 8 to 25, further comprising dewatering means for dewatering the collected solids downstream of said vessel.
27. An apparatus as claimed in claim 26, wherein said dewatering means comprise a centrifugal separator or a screw conveyor or similar.
PCT/EP2012/054451 2011-03-14 2012-03-14 Method and apparatus for separating solids from a liquid suspension thereof WO2012123489A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB1104210.8 2011-03-14
GB1104210.8A GB2488995B (en) 2011-03-14 2011-03-14 Apparatus for separating solids from a liquid suspension thereof

Publications (1)

Publication Number Publication Date
WO2012123489A1 true WO2012123489A1 (en) 2012-09-20

Family

ID=43980894

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2012/054451 WO2012123489A1 (en) 2011-03-14 2012-03-14 Method and apparatus for separating solids from a liquid suspension thereof

Country Status (2)

Country Link
GB (1) GB2488995B (en)
WO (1) WO2012123489A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104709621A (en) * 2015-03-17 2015-06-17 张建臣 Liquid laminar flow processor
CN111995022A (en) * 2020-08-31 2020-11-27 李玲 Solid-liquid separation equipment, use method thereof and sewage treatment system
CN114247211A (en) * 2022-03-02 2022-03-29 山东沃华远达环境科技股份有限公司 Medical sewage treatment device based on centrifugal separation is carried out floater
CN114797194A (en) * 2022-04-11 2022-07-29 贺诚 Virtual pool bottom, separation method and double-cyclone separator based on virtual pool bottom

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015114519A1 (en) * 2015-07-07 2017-01-12 Pwk Wasser & Kunststofftechnik Gmbh & Co. Kg Tangential Separator (TS)
WO2018058197A1 (en) * 2016-09-30 2018-04-05 Hydrus Technology Pty. Ltd. Clarifier
WO2021232103A1 (en) * 2020-05-20 2021-11-25 Ryan Wallis Mine wastewater desludging apparatus
CN112843798A (en) * 2020-12-28 2021-05-28 应康伟 Sewage treatment device capable of carrying out sludge treatment

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2425932A (en) * 1947-08-19 Gkit separator
US3965013A (en) * 1974-10-31 1976-06-22 Jackson George F Gravity clarifier
EP1002563A1 (en) * 1998-11-17 2000-05-24 FirstEnergy Ventures Method and apparatus for separating fast settling particles from slow settling particles

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2899823B1 (en) * 2006-04-18 2008-08-29 Labono Sas EFFLUENT PURIFICATION DEVICE
JP4872117B2 (en) * 2008-01-21 2012-02-08 有限会社カワセツ Continuous coagulation treatment equipment for contaminated water

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2425932A (en) * 1947-08-19 Gkit separator
US3965013A (en) * 1974-10-31 1976-06-22 Jackson George F Gravity clarifier
EP1002563A1 (en) * 1998-11-17 2000-05-24 FirstEnergy Ventures Method and apparatus for separating fast settling particles from slow settling particles

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104709621A (en) * 2015-03-17 2015-06-17 张建臣 Liquid laminar flow processor
CN111995022A (en) * 2020-08-31 2020-11-27 李玲 Solid-liquid separation equipment, use method thereof and sewage treatment system
CN114247211A (en) * 2022-03-02 2022-03-29 山东沃华远达环境科技股份有限公司 Medical sewage treatment device based on centrifugal separation is carried out floater
CN114247211B (en) * 2022-03-02 2022-05-06 山东沃华远达环境科技股份有限公司 Medical sewage treatment device based on centrifugal separation is carried out floater
CN114797194A (en) * 2022-04-11 2022-07-29 贺诚 Virtual pool bottom, separation method and double-cyclone separator based on virtual pool bottom

Also Published As

Publication number Publication date
GB2488995B (en) 2013-05-29
GB2488995A (en) 2012-09-19
GB201104210D0 (en) 2011-04-27

Similar Documents

Publication Publication Date Title
WO2012123489A1 (en) Method and apparatus for separating solids from a liquid suspension thereof
CN101428247B (en) Pollution-free oil-containing mud cleaning treatment method and treatment system thereof
CN101580322B (en) Sewage processing method and sewage processing device
US4999115A (en) Method and apparatus for use in separating solids from liquids
KR101358629B1 (en) Cyclone settling apparatus
WO2009137867A1 (en) Apparatus and method for mechanical deaeration
KR102406986B1 (en) Wastewater treatment device
CA2788623C (en) Ballast flocculation and sedimentation water treatment system with simplified sludge recirculation, and process therefor
CN209537204U (en) Magnetic loads water treatment facilities
JP2008246282A (en) Muddy water purifying separator
CN107983526B (en) Grading treatment process of silicon carbide micro powder
JP3676659B2 (en) Solid-liquid separator having stirring flow forming means
CN107473339B (en) Mine water magnetic coagulation treatment device and process
CN207619149U (en) A kind of granulation clarification desulfurization wastewater treatment system
CN105833569A (en) Outer rotational flow limited flow channel membrane separator and method for demulsifying emulsion membrane through same
CN201458889U (en) Sewage treatment device
WO1997035655A1 (en) Water treatment system
CN102153213A (en) Two-stage centrifugal desliming technology
KR200220590Y1 (en) Sewage treatment centrifuge with separation of suspended solids
KR101889663B1 (en) Circular Type Thickener
WO1997035654A1 (en) Wastewater treatment system
CN111807677A (en) Zero-emission purification treatment method and treatment system for high-viscosity polymer-containing oil sludge
KR900006074B1 (en) Method and apparatus for seperating solids from liquids
CN210261531U (en) Zero-emission purification treatment system for high-viscosity polymer-containing oil sludge sand
KR102308038B1 (en) Integrated waste water treatment tank facility for wet type sand product plant

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12709092

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 12709092

Country of ref document: EP

Kind code of ref document: A1