WO2009010631A1 - Procédé d'utilisation d'un séparateur et séparateur - Google Patents

Procédé d'utilisation d'un séparateur et séparateur Download PDF

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Publication number
WO2009010631A1
WO2009010631A1 PCT/FI2008/050424 FI2008050424W WO2009010631A1 WO 2009010631 A1 WO2009010631 A1 WO 2009010631A1 FI 2008050424 W FI2008050424 W FI 2008050424W WO 2009010631 A1 WO2009010631 A1 WO 2009010631A1
Authority
WO
WIPO (PCT)
Prior art keywords
liquid
bowl
separated
pressure
separator
Prior art date
Application number
PCT/FI2008/050424
Other languages
English (en)
Inventor
Raine Peltokoski
Original Assignee
Wärtsilä Finland Oy
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 Wärtsilä Finland Oy filed Critical Wärtsilä Finland Oy
Priority to EP08787701.5A priority Critical patent/EP2170521B1/fr
Publication of WO2009010631A1 publication Critical patent/WO2009010631A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/04—Periodical feeding or discharging; Control arrangements therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B1/00—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles
    • B04B1/04—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles with inserted separating walls
    • B04B1/08—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles with inserted separating walls of conical shape
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B1/00—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles
    • B04B1/10—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles with discharging outlets in the plane of the maximum diameter of the bowl
    • B04B1/14—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles with discharging outlets in the plane of the maximum diameter of the bowl with periodical discharge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B13/00—Control arrangements specially designed for centrifuges; Programme control of centrifuges

Definitions

  • the invention relates to a method of using a centrifugal separator.
  • the invention also relates to a centrifugal separator.
  • centrifugal separator can additionally be used for separating sludge and other solids from a liquid.
  • a separator com- prises a rotatable bowl, i.e. a rotor, having a stack of disks and a sludge vol ⁇ ume for the liquid to be separated.
  • the solids and/or the heavier liquid i.e. the liquid having a higher density
  • the separated liquid is transferred through the disk stack to the inner part of the bowl, wherefrom it is discharged from the separator.
  • centrifugal separators in connection with piston engines in marine or power plant use are used for separating sludge and water from l ⁇ bri- cation oil and fuel oil.
  • the sludge separated from the oil is periodically discharged from the bowl via an outlet opening during discharge sequences.
  • heavier liquid i.e. so-called displacement water
  • the lighter liquid i.e. oil
  • the pressure of the separated liquid that is to be removed from the separator is measured. If during an alarm delay, the pressure does not increase to a predetermined limit value, there may be a failure in the separator and the control system of the separator triggers the alarm. If the volume flow of the liquid to be sepa ⁇ rated is low, the filling of the separator and the increase in pressure to a suffi- cient level after the discharge sequence may take longer than the duration of the alarm delay, whereby the control system triggers an unnecessary alarm.
  • the object of the invention is to provide a solution that can be used to optimize the duration of the alarm delay of the separator.
  • the invention provides considerable advantages.
  • the duration of the alarm delay can be optimized on the basis the volume flow of the liquid to be scpa- rated which reduces the number of fatse alarms when the volume flow of the liquid to be separated is low.
  • the alarm in the event of a failure, the alarm can be triggered earlier when the volume flow of the liquid to be separated is high.
  • centrifugal separator 1 used for separating two liquids having different densities from each other and/or separating sludge and other solids from the liquid.
  • centrifugal separators 1 There are two main types of centrifugal separators 1.
  • One is a so-called clarifier separator, used for separating solids and sludge from liquid.
  • the other is the so-called purifier separator used for separating heavier liquid and solids/siudge from a lighter liquid.
  • the centrifugal separator 1 can be used for separating water and/or sludge and other solids from fuei and lubrication oii from the oil.
  • the centrifugal separator 1 can be either of the above-mentioned types.
  • the separator 1 comprises a rotor i.e. a bowl 2 rotatable about an axis of rotation 3.
  • the bowl 2 comprises a body 4 inside which there is a disk stack 13 and sludge volume 6.
  • the body 4 comprises two halves arranged against each other, a lower half 27 and an upper half 26, The lower half is pressed against the upper half by means of a force caused by the pressure of closure liquid introduced into the closure chamber 24 via line 25.
  • the disk stack 13 and the sludge volume 6 envelope the axis of rotation 3, whereby sludge and other solids and/or liquid having higher density are transferred by centrifugal force during the rotation of the bowl 2 into the outermost volume of the bowl, the so-called sludge volume 6.
  • the liquid having smaller density is transferred into the innermost part 7 of the bowl.
  • the bowl 2 is enveloped by a stationary housing (not shown).
  • the separator 1 has an inlet duct, i.e. a stationary iniet tube 8 for introducing the liquid to be separated into the bowl 2.
  • the inlet tube 8 has a pump 9 by means of which liquid is pumped into the bowl 2.
  • the rotation speed of the pump 9 is regulated by means of a frequency converter 10.
  • the bowl 2 com- prises a disk stack 13 between the disks of which the heavier liquid and/or sludge or other solids are separated from the lighter liquid.
  • the inlet tube 8 is located in the middle part of the bowl 2 parallel with the axis of rotation 3 and its inlet opening is on the axis of rotation 3, whereby the liquid to be sepa- rated is introduced to the lower part of the bowl 2, under the distributor 28 located under the disk stack 13.
  • the separator 1 also has an outlet duct, i.e. a stationary discharge tube 11, for discharging the separated, i.e. lighter liquid i.e. liquid having a lower density from the bowl 2.
  • the opening of the discharge tube 11 is located in the inner part 7 of the bowl.
  • the discharge tube 11 is provided with a pressure sensor 12 for measuring the pressure of the separated, i.e. lighter, liquid discharged from the separator.
  • the outer circumference of the bowl 2 comprises openable and closable discharge openings 14 through which sludge and other solids are removed from the bowl during the discharge sequence.
  • the discharge openings are opened by sliding the lower haif 27 downwards.
  • the movement of the lower half 27 is provided by means of control liquid introduced to the control chamber 17 via a control liquid channel 16.
  • the control chamber 17 comprises a discharge mechanism that allows the pressure in closure chamber 24 to be discharged via the nozzles 23 of the control chamber 17 by the influence of the pressure of the control fluid.
  • the pressure in the bowl 5 causes the tower half 27 to slide downwards and the discharge openings open.
  • the bowi is closed by ending the introduction of control liquid into the control chamber 17 and by adding closure liquid into the closure chamber 24.
  • Tho separator 1 is provided with a displacement liquid inlet tube 19 connected to the inlet tube 8 for introducing displacement liquid to the bowl 2 via inlet tube 8. Introduction of displacement liquid fills the bowl with a heavier liquid and thus prevents discharging the lighter liquid from the bowl via dis- charge openings 14 during the discharge sequence.
  • the inlet tube 19 of displacement liquid is provided with a closure valve 20, such as an electric solenoid valve by means of which the flow of displacement liquid into the bowl can be allowed or prevented.
  • the inlet tube 19 of the displacement liquid is provided with a pressure sensor 21 for measuring the pressure of the d ⁇ s- placement liquid. The sensor 21 is located before the closure valve 20 in the flow direction of the displacement liquid in the displacement liquid inlet tube 19.
  • the separator 1 additionally comprises an electric control system 22 arranged to collect information from various measurement points, i.e. the measurement signals of the displacement liquid pressure sensor 21 and the discharge tube pressure sensor 21.
  • the control system 22 controls the closure valve 20 on the basis of the pressure measurement of the displacement liquid.
  • the control system 22 adjusts the opening time of the closure valve 20 i.e. the in- troduction time of displacement liquid into the bowl 2 on the basis of the measurement data from the pressure sensor 21.
  • the displacement liquid introduction volume is thus kept constant or nearly constant during the introduction sequence.
  • control system 22 is provided with information about the control frequency or output frequency of the frequency converter 10, the frequencies being at least nearly relative to the rotation speed of the pump 9, and the measurement signal of the pressure sensor of the discharge tube 12.
  • the control system 22 adjusts the length of the alarm delay after the dis ⁇ charge sequence on the basis of the rotation speed of the pump 9. An alarm is triggered if after the discharge sequence, during an alarm delay subse ⁇ quent to the beginning of the separation, there is no signal indicating suffi- cie ⁇ t pressure from the pressure sensor of the discharge tube 12, i.e. there is no liquid flow at all in the discharge tube or the pressure of the liquid is too low.
  • the bow! 2 is rotated about the axis of rotation 3 during the operation of the centrifugal separator 1.
  • the liquid to be separated is pumped with a pump 9 via inlet tube 8 to the bowl 2.
  • the flow of the liquid introduced into the bowl 2 is adjusted to be suitable by changing the rotation speed of the pump 9 by means of a frequency converter 10.
  • the control system 22 changes the output frequency of the frequency converter 10, i.e. in practice the rotation speed of the pump 9 on the basis of the need at the target application of the separated liquid.
  • the heavier liquid i.e. liquid with a higher density, and/or sludge and other solids are transferred to the outer part of the bowl, i.e. the sludge volume 6.
  • the lighter liquid, i.e. liquid with a lower density is transferred through the disk stack 13 into the inner part 7.
  • a purifier type separa- tor the heavier liquid is continuously discharged from the outer part 6 via a so-called gravity disc (not shown).
  • Separated, i.e. lighter, liquid is removed from the bowl 2 via discharge tube 11. Heavier liquid and/or sludge and solids are discharged from the sludge volume 6 of the bowl periodically via discharge openings 14, Prior to beginning of the discharge sequence the introduction of the liquid to be separated to the bowl 2 via the inlet channel 8 is stopped. Subsequent to this, the closure valve 20 is opened and the introduction of displacement liquid to the bowl 2 is started. The density of the displacement liquid is higher than that of the separated liquid. Usually the displacement liquid is the same as the heavier liquid in the sludge volume 6 of the bowl, typically water. Due to the in ⁇ troduction of the displacement liquid the amount of the heavier liquid in the bowl 2 is increased, whereby the interface 29 between the lighter and the heavier liquid moves towards the inner part 7 of the bowl.
  • a suitable introduction amount of displacement liquid can be defined, for example, by testing or on the basis of the properties of the liquid to be separated.
  • the duration of the introduction sequence is adjusted on the basis of the pressure of the displacement liquid. The pressure of the displacement liquid is measured in the displacement liquid introduction tube by means of measuring device 21 and the measurement signal in directed to the control system 22.
  • the control system 22 defines the duration of the introduction sequence on the basis of the measured pressure of the displacement liquid and controls the closure valve 20 correspondingly.
  • the aim is to maintain a constant or essentially constant amount of displacement liquid being introduced into the bowl during the introduction sequence. For example, if the pressure of the displacement liquid is 6 bar, the duration of the introduction sequence is adjusted to 4 seconds. Correspondingly, if the pressure of the displacement liquid is 2 bar, the length of the introduction sequence is 7 seconds.
  • the introduction of the displacement liquid is stopped by closing the closure valve 20.
  • Control liquid is introduced into the control chamber 17 via control channel 16. Due to the hydraulic pressure in the control cham- ber 17 the lower half of the bow! is displaced from its place, revealing the discharge openings 14. The heavier liquid and sludge are discharged from the bowl via discharge openings 14 to the housing enveloping the bowl.
  • the aim is to provide as smali as possible loss of the lighter, separated liquid, usually oil, during the discharge of the bowl.
  • the in- troduction of control liquid is stopped and the hydraulic pressure in the control chamber 17 is discharged via nozzles 23.
  • closure liquid is introduced under the lower half 26 of the bowl into the chamber 24, whereby the lower half 27 moves upwards and again covers the discharge openings 14 and the discharge sequence ends.
  • the length of the discharge sequence is about one second or some seconds, if the introduction of control liquid and closure liquid are controlled by different solenoid valves.
  • the same control liquid both opens and closes using channel arrangements inside the bowl in less than a second, even in a fraction of a second.
  • the adjustment of the duration of the displacement liquid introduction sequence can be carried out as an adjustment taking place as a function of a continuous measurement. For example, as the closure valve 20 opens, the pressure of the displacement liquid in the displacement liquid inlet tube 19 decreases. The pressure of the displacement liquid in the inlet tube 19 is continuously measured during the introduction sequence and the control system 22 continuously defines a new value for the duration of the introduction sequence on the basis of the average pressure during the introduction se- quence. When the duration of the displacement liquid introduction sequence defined on the basis of the average pressure is reached, the control system 22 closes the closure valve 20 and the introduction of displacement liquid into the bowl 2 ends. In this embodiment it is also desirable to maintain the amount of displacement liquid introduced into the bowl 2 constant or essen- tially constant during the introduction sequence regardless of pressure changes.
  • the adjustment of the duration of the displacement liquid introduction sequence can also be carried out by calculating the volume flow of the dis- placement liquid with the Bernoulli equation.
  • the pressure measurements of the inlet tube 19 and the throttle allow calculating the volume flow of the liquid flowing in the inlet tube 19 of the displacement liquid by using Ber- noulli's equation and continuity equation, when the measurement points of pressure are at the same height.
  • the flow speed can be used for determining the volume flow of the displacement liquid by using the cross-sectional flow area of the displacement liquid inlet tube.
  • the control system 22 defines the duration of the introduction sequence on the basis of the throttle of the water volume flowing the displacement liquid inlet tube 19 and the pressure measurements of the inlet tube 19 and controls the closure valve so that the amount of water introduced into the bowl during the introduction duration of the displacement liquid is as desired, In this embodiment it is also desirable to maintain the amount of displacement liquid introduced into the bowl constant or essentially constant during the introduction sequence regardless of pressure changes.
  • the correct opening time is calculated continuously for the displacement water valve 20.
  • the control system 22 also changes the length of the alarm delay as a function of the volume flow of the liquid to be separated introduced into the separator.
  • the alarm delay starts when separating is started again after the discharge sequence has ended.
  • an alarm is triggered.
  • the pressure of the separated liquid is measured by means of a pressure sensor 12 and the control system 22 triggers an alarm in case the signal from the pressure sensor 12 indicates the pressure in the discharge tube 11 to be less than a predetermined limit value after the alarm delay. Too low a pressure in the discharge tube 11 after the alarm delay can mean a malfunction of the separator, such the discharge openings 14 having not closed.
  • the alarm limit of pressure can be, for example, the same as the minimum pressure required by the target application of the separated liquid.
  • the rotation speed of the pump 9 has an effect on the speed at which the pressure in the discharge tube 11 returns to its normal level after the discharge sequence of the separation chamber 5. With a lower rotation speed the separator fills and the pressure returns slower than with a higher speed.
  • the length of the alarm delay is adjusted on the basis of the volume flow of the liquid to be separated introduced into the separator.
  • the volume flow of the liquid to be separated can be defined with, for example, a measurement apparatus suitable for the purpose or on the basis of the rotation speed of the pump 9 or on the basis of the output frequency or control frequency of the frequency converter 10.
  • the control system 22 adjusts the length of the alarm delay. For example, when the pump rotates at a speed corresponding to a frequency converter output frequency of 50 Hz, the length of the alarm delay is 10 seconds. If the rotation speed of the pump 9 changes to correspond with a frequency converter output frequency of 15 Hz, the control system 22 changes the length of the alarm delay to 40 seconds.
  • the alarm con be, for example, a message displayed on screen in the control room and/or the control system 22 can cut the introduction of the liquid to be separated into the separator.
  • the duration of the sealing liquid introduction sequence (purifier separator) can be defined using the pressure measurement of the sealing liquid with methods s ⁇ m ⁇ iar to those used for de- fining the length of the displacement liquid introduction sequence. The same methods can also be used for defining the durations of the introduction sequences of control liquid and closure liquid.

Landscapes

  • Centrifugal Separators (AREA)

Abstract

L'invention concerne un séparateur centrifuge et un procédé d'utilisation d'un séparateur centrifuge (1) comprenant une cuve (2) pour le liquide destiné à être séparé. Ledit procédé consiste à injecter le liquide destiné à être séparé dans la cuve (2), à évacuer le liquide séparé de la partie interne (7) de la cuve, à éliminer périodiquement les scories du récipient extérieur (6) de la cuve au cours des cycles de vidange, à mesurer la pression du liquide séparé évacué de la cuve (2), et à déclencher une alarme, si après le retard d'alarme suivant le cycle de vidange, la pression du liquide séparé évacué de la cuve (2) se trouve en dessous d'une valeur limite préétablie. Le flux volumique du liquide injecté dans la cuve (2) et séparé est défini, et la durée du retard d'alarme est réglée en fonction du flux volumique du liquide destiné à être séparé.
PCT/FI2008/050424 2007-07-13 2008-07-10 Procédé d'utilisation d'un séparateur et séparateur WO2009010631A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP08787701.5A EP2170521B1 (fr) 2007-07-13 2008-07-10 Procédé d'utilisation d'un séparateur et séparateur

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI20075544 2007-07-13
FI20075544A FI119975B (fi) 2007-07-13 2007-07-13 Menetelmä separaattorin käyttämiseksi ja separaattori

Publications (1)

Publication Number Publication Date
WO2009010631A1 true WO2009010631A1 (fr) 2009-01-22

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI2008/050424 WO2009010631A1 (fr) 2007-07-13 2008-07-10 Procédé d'utilisation d'un séparateur et séparateur

Country Status (3)

Country Link
EP (1) EP2170521B1 (fr)
FI (1) FI119975B (fr)
WO (1) WO2009010631A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7678039B2 (en) * 2006-02-13 2010-03-16 Alfa Laval Corporate Ab Method of monitoring operation of a centrifugal separator using pressure measurement
US8702576B2 (en) * 2010-03-19 2014-04-22 Alfa Laval Corporate Ab Device and method for monitoring and adjusting the radial position of an interface layer in a nozzle centrifuge
KR20160137583A (ko) * 2014-03-31 2016-11-30 바르실라 핀랜드 오이 원심 분리기의 배출 시기를 제어하기 위한 방법 및 원심 분리기
CN110538727A (zh) * 2019-09-26 2019-12-06 南京绿岛机械设备有限公司 一种带有自排渣结构的乳胶碟式分离机

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5800330A (en) * 1994-07-22 1998-09-01 Alfa Laval Ab Method and equipment for monitoring a centrifugal separator
WO2000053331A1 (fr) * 1999-03-08 2000-09-14 Alfa Laval Ab Procede et appareil indiquant un etat de fonctionnement non desire dans un separateur centrifuge

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5800330A (en) * 1994-07-22 1998-09-01 Alfa Laval Ab Method and equipment for monitoring a centrifugal separator
WO2000053331A1 (fr) * 1999-03-08 2000-09-14 Alfa Laval Ab Procede et appareil indiquant un etat de fonctionnement non desire dans un separateur centrifuge

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7678039B2 (en) * 2006-02-13 2010-03-16 Alfa Laval Corporate Ab Method of monitoring operation of a centrifugal separator using pressure measurement
US8702576B2 (en) * 2010-03-19 2014-04-22 Alfa Laval Corporate Ab Device and method for monitoring and adjusting the radial position of an interface layer in a nozzle centrifuge
KR20160137583A (ko) * 2014-03-31 2016-11-30 바르실라 핀랜드 오이 원심 분리기의 배출 시기를 제어하기 위한 방법 및 원심 분리기
JP2017509479A (ja) * 2014-03-31 2017-04-06 ワルトシラ フィンランド オサケユキチュア 遠心分離機の排出タイミング制御方法及び遠心分離機
US10201817B2 (en) 2014-03-31 2019-02-12 Wartsila Finland Oy Method for controlling discharge timing of centrifugal separator and centrifugal separator based on pressure measurement
KR102266818B1 (ko) * 2014-03-31 2021-06-17 바르실라 핀랜드 오이 원심 분리기의 배출 시기를 제어하기 위한 방법 및 원심 분리기
CN110538727A (zh) * 2019-09-26 2019-12-06 南京绿岛机械设备有限公司 一种带有自排渣结构的乳胶碟式分离机

Also Published As

Publication number Publication date
EP2170521B1 (fr) 2017-04-19
EP2170521A1 (fr) 2010-04-07
FI20075544A0 (fi) 2007-07-13
FI20075544A (fi) 2009-01-14
FI119975B (fi) 2009-05-29

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