WO1998044188A1 - Procede et appareil permettant de remplir un reservoir de pate a papier - Google Patents

Procede et appareil permettant de remplir un reservoir de pate a papier Download PDF

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Publication number
WO1998044188A1
WO1998044188A1 PCT/FI1998/000286 FI9800286W WO9844188A1 WO 1998044188 A1 WO1998044188 A1 WO 1998044188A1 FI 9800286 W FI9800286 W FI 9800286W WO 9844188 A1 WO9844188 A1 WO 9844188A1
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WO
WIPO (PCT)
Prior art keywords
pulp
tank
recited
feeding member
feeding
Prior art date
Application number
PCT/FI1998/000286
Other languages
English (en)
Finnish (fi)
Inventor
Olavi Toukonummi
Original Assignee
Ahlström Pumput 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 Ahlström Pumput Oy filed Critical Ahlström Pumput Oy
Priority to AU67328/98A priority Critical patent/AU6732898A/en
Publication of WO1998044188A1 publication Critical patent/WO1998044188A1/fr

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1026—Other features in bleaching processes
    • D21C9/1052—Controlling the process
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C7/00—Digesters
    • D21C7/06—Feeding devices

Definitions

  • the present invention relates to a method and apparatus for filling a pulp tank.
  • the invention is especially well applicable in the wood processing industry to filling high consistency pulp tanks, storage and bleaching tanks, and corresponding tanks containing fiber suspensions .
  • Pulp tanks used in the wood processing industry are most commonly tanks containing high-consistency pulp, the consistency being 10 - 20 %, although pulp at a lower consistency is also used occasionally. These tanks are used for example for storing pulp or as blow tanks of some apparatus, i.e. for example for storing pulp which comes in batches from batch digesters, the pulp being then used as a uniform flow in the subsequent treatment apparatus. In other words, it is characteristic of tanks according to the invention that the level thereof varies to a great extent, although they most commonly have an optimum level, and the intention is to keep the surface of the pulp at this level .
  • a complete change of stock in towers like this may take days or at least several hours, the pulp discharged from the tank being thus a mixture of old and new pulp of this time span.
  • this "intermediate pulp” may in the worst case be totally unusable.
  • the old pulp staying longer in the tank and the new pulp permeating deeper into the tank liquid is gradually filtered from the surface of the pulp layer, whereby the surface layer hardens and gets thus damaged more easily.
  • the pulp is introduced from down below a rotating plate provided with blades (SE-C-502 , 971) in such a way that the blades spread the pulp turned into drops in the device all over the cross-section of the tower.
  • the rotative velocity of the electric motor used for the rotating of the plate may be changed to achieve different spreading degrees for the pulp, whatever that means.
  • This method has the same problems as the rotating plate, i.e. the pulp turns into drops and a lot of air is bound to the pulp.
  • Another problem which could be mentioned is that when using rotating plates or the like described in the prior art, the changing of the surface level is not taken into account and therefore such plates are applicable only to a particular standard surface level .
  • the surface level most often corresponds to a full tank, in which case the plate or the like is located only a little above the pulp level in the tower.
  • the presumption is that the process is continuous and the surface level of the tower is therefore standard - which is the case in many objects of use, of course - whereby it would suffice to adjust the rotative velocity of the plate suitable for the standard surface level when taking the apparatus into use .
  • the plate In a case where there is less pulp in the tower, the plate would throw the pulp against the wall of the tower, and at this phase at the latest, the pulp would be turned into drops, binding a large amount of air to itself.
  • US patent publication 4,278,498 discloses a filling arrangement for a bleaching tower, in which the pulp is introduced into the tower through a rotating tube channel in such a way that it is spread into the tower in layers .
  • the method relates to a continuous process, in which the surface level of the tower is virtually standard, and in which, according to our understanding, it is not that important for the pulp to be spread quite uniformly into the tower, as the consistency of the pulp introduced therein is in the HC range, i.e. 35 - 50 %, according to the publication. With consistencies this high there is no substantial risk that the pulp would penetrate deep into the pulp layer already in the tower, as far as the feeding direction is not quite vertical.
  • a further problem not treated above relates to storage of bleached pulp.
  • Fig. 1 One example of this is illustrated in which the brightness of the pulp discharged out of the tower is presented as a function of the surface level of the tower, according to measurements performed in a cellulose mill. The figure shows, first of all, that the brightness of the pulp decreases as the surface in the tower sinks.
  • Fig. 1 is a graphic illustration of a problem observed in connection with a prior art pulp tank, i.e. an illustration of the brightness of pulp as a function of the surface level of the tank; and Fig. 2 is an illustration of an apparatus in accordance with a preferred embodiment of the invention;
  • the apparatus comprises a rotating feeding member 12 arranged in the upper part of the pulp tank 10, preferably on the top or cover thereof, and preferably in connection with the shaft being central relative to the tank; means 14 to rotate the feeding member; means 16 to introduce pulp to said feeding member 12; and means 18 to control the operation of the feeding member.
  • the means 16 may be composed of a tube directed through the cover of the tank, as illustrated in Fig. 2, or alternatively of a tube extending through the side wall to the central axis of the tank, or of the like.
  • the feeding member 12 is a tube curve arranged in the lower part of a vertical pulp tube or the like, the supply opening of which is directed substantially toward the wall of the tank, i.e. the pulp tank 10.
  • the form of the device is not such that it would turn a pulp flow into drops; instead, it attempts to keep the pulp flow uniform, thus preventing the binding of air to the pulp as far possible.
  • the supply opening of the tube curve is directed horizontally or to some extent upward or downward but the essential thing is that the supply direction of the pulp from the supply opening together with the rotative velocity of said feeding device ensure that the pulp can be supplied under all operating conditions of the tank (i.e.
  • the rotating means 14 of the feeding device is preferably an electric motor, the velocity of which can be controlled. If needed, the motor is provided with a reduction gear.
  • the controlling means 18 of said feeding device 12 comprise a surface level detector, which is a part of the standard equipment of any tank, and of a control unit 22.
  • the control unit in turn, comprise a clock or a corresponding timer device used in the way described in the following examples .
  • the control unit 22 has originally been given information at least on the diameter of the tank, the height of the feeding member and the pressure and/or velocity of the pulp in the feeding member 12. Having received the information on the surface level of the tank, the control unit 22 can, on the basis of the calculation algorithm created for it beforehand, determine the rotative velocity of the feeding member 12 in such a way that the pulp flow discharging from the feeding member 12 will end up at the connecting point of the wall of the tank 10 and the pulp surface. In practice, this velocity becomes the maximum rotative velocity of the feeding member 12.
  • the control unit 22 maintains the rotative velocity of the feeding member 12 standard for a given time (by means of the timer) , for example in such a way that pulp is fed to the border area of the tank to such an extent that the surface changes about 50 cm, or more generally expressed, the desired amount.
  • the rotative velocity of the feeding member 12 is reduced either evenly or step by step so that each point of the tank (the diameter of the tank) receives an equal amount (measured as the change in the surface level) of pulp.
  • control unit 22 determines the required rotative velocity for the feeding member 12 and the maintenance time of the velocity.
  • the control unit is "taught" to act in a predetermined way. This "teaching" is done in such a way that at each height of the tank (for example at intervals of 1 m) , the following are determined: the maximum rotative velocity of the feeding member, and a required number of lower rotating velocities and the maintenance times thereof, by means of which the tank can be filled substantially evenly.
  • the control unit selects the information to be used in control of the operation of the feeding member on the basis of the information given to it by the the surface level detector.
  • the tank is being filled or emptied, which means that the surface level in the tank varies, in other words the pulp flow entering the tank and the one to be removed from the tank are not in balance.
  • the control unit 22 must be able to detect the surface level of the tank all the time and to draw conclusions on the basis of that for the required changes to the operating information of the feeding member 12.
  • the control unit 22 has to be able to take into account that the feed jet behaves in a different manner when the surface level of the tank is low than when it is in the middle or upper part of the tank.
  • the best way to "teach" these aspects to the control unit 22 is in the manner described above. In other words, when taking the apparatus into use, optimum values are determined for each surface level as well as for the rotating velocities of the feeding member 12 and the maintenance times thereof.
  • another way to control the filling of the tank is to construct the feeding member in such a way that the direction of the pulp flow coming out of it changes, whereby also the distance from the axis of the tank to which the pulp flow extends, changes as well.
  • This may be effected for example by arranging the direction of the supply opening to be changed by a special guide plate or chute. When turning this plate or chute chiefly on a horizontal plane, the direction and extension range of the pulp flow in the tank changes.
  • Another possibility is to arrange a guide plate at the end of a substantially vertical feeding tube. Said plate would either stay in position, rotate or be rotatable, and would be located at a given distance from the inlet opening of the tube, being movable in a vertical direction.
  • the diameter of such a plate may be larger than the inlet opening of the feeding tube, in which case the shorter the distance between the inlet opening and the plate is, the longer the distance of the pulp flow is from the center of the tank, due to the effect of the plate.
  • the guide plate may be totally horizontal, although preferably it is conical, guiding hence pulp to the side. In all embodiments described here, it is possible to keep the rotative velocity standard and to change some other parameter affecting the course of the pulp to be fed to the tank. These parameters may be "taught" to the control unit in the way described above, or it is also possible to create a calculation algorithm for the parameters, by means of which the control unit is able to determine the changes required in the course of the pulp in order for the tank to be filled evenly.
  • the feeding means when using a horizontal or conical plate disposed at the end of the feeding tube, the feeding means does not necessarily have to rotate at all, but it is possible to affect the course of the pulp passing to the tank by changing the position of the guide plate.
  • Yet one use of object according to the invention worth mentioning is the cleaning of the wall of the tank in a case where some pulp has been stuck to the wall .
  • either the rotative velocity of the feeding means or the direction of the inlet opening thereof is changed in such a way that the pulp flow will hit the wall of the tank, detaching thus the pulp layer stuck to it.
  • Such a function may be arranged either at a particular level of the tank wall or extended to the whole height of the tank.
  • the control unit may be "taught" to perform a wash of the whole wall surface, for example once a week.
  • the form of the tank does not have to be as described in the appended figure, i.e. a tank with a cylindric bottom portion narrowed by an intermediate part, but it may as well be cylindric all over its height and provided with either an even or inclined bottom, or with a cylindric or semi-spherical bottom portion.
  • the filling arrangement according to the invention is applicable to the filling of tanks of any form.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

La présente invention concerne un procédé et un appareil permettant de remplir un réservoir de pâte à papier, et est caractérisée en ce que la pâte est dirigée dans un réservoir (10) par l'intermédiaire d'un élément d'alimentation rotatif (12) monté en liaison avec le couvercle ou au moins sur la partie supérieure du réservoir de telle sorte que la plage d'extension d'écoulement de la pâte en provenance de l'élément d'alimentation (12) soit modifiée de façon à remplir le réservoir (10) uniformément au moyen d'un détecteur de niveau de surface et d'une unité de commande (22).
PCT/FI1998/000286 1997-04-01 1998-03-31 Procede et appareil permettant de remplir un reservoir de pate a papier WO1998044188A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU67328/98A AU6732898A (en) 1997-04-01 1998-03-31 Method and apparatus for filling a pulp tank

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI971330 1997-04-01
FI971330A FI118130B (fi) 1997-04-01 1997-04-01 Menetelmä ja laitteisto massatornin täyttämiseksi

Publications (1)

Publication Number Publication Date
WO1998044188A1 true WO1998044188A1 (fr) 1998-10-08

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1998/000286 WO1998044188A1 (fr) 1997-04-01 1998-03-31 Procede et appareil permettant de remplir un reservoir de pate a papier

Country Status (3)

Country Link
AU (1) AU6732898A (fr)
FI (1) FI118130B (fr)
WO (1) WO1998044188A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008028771A1 (fr) 2006-09-07 2008-03-13 Sulzer Pumpen Ag Procédé et appareil de remplissage et de nettoyage d'une tour de pâte à papier
CN105780573A (zh) * 2016-04-14 2016-07-20 华南理工大学 一种中浓浆泵立管液位自动调节方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI108150B (fi) 1999-02-15 2001-11-30 Sulzer Pumpen Ag Menetelmä ja laitteisto massan käsittelemiseksi

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE491166C (de) * 1928-09-06 1930-02-11 Tryggve Ferdinand Christiansen Vorrichtung zum Ein- bzw. Auffuellen von zerkleinertem Holz u. dgl. in Zellstoffkochern
US2858213A (en) * 1956-04-20 1958-10-28 Condi Engineering Corp Wood chip digestion
US2990710A (en) * 1958-10-13 1961-07-04 Improved Machinery Inc Pulp bleaching apparatus
US3053068A (en) * 1957-08-21 1962-09-11 Sunds Verkst Er Aktiebolag Towers for bleaching pulp material, especially cellulose pulp
US4621507A (en) * 1984-04-02 1986-11-11 Kamyr Ab Distributing device for suspensions
WO1995008020A1 (fr) * 1993-09-16 1995-03-23 Kvaerner Pulping Technologies Ab Agencement d'etalage de pate a papier dans un conteneur

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE491166C (de) * 1928-09-06 1930-02-11 Tryggve Ferdinand Christiansen Vorrichtung zum Ein- bzw. Auffuellen von zerkleinertem Holz u. dgl. in Zellstoffkochern
US2858213A (en) * 1956-04-20 1958-10-28 Condi Engineering Corp Wood chip digestion
US3053068A (en) * 1957-08-21 1962-09-11 Sunds Verkst Er Aktiebolag Towers for bleaching pulp material, especially cellulose pulp
US2990710A (en) * 1958-10-13 1961-07-04 Improved Machinery Inc Pulp bleaching apparatus
US4621507A (en) * 1984-04-02 1986-11-11 Kamyr Ab Distributing device for suspensions
WO1995008020A1 (fr) * 1993-09-16 1995-03-23 Kvaerner Pulping Technologies Ab Agencement d'etalage de pate a papier dans un conteneur

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2008028771A1 (fr) 2006-09-07 2008-03-13 Sulzer Pumpen Ag Procédé et appareil de remplissage et de nettoyage d'une tour de pâte à papier
US8128785B2 (en) 2006-09-07 2012-03-06 Sulzer Pumpen Ag Method and apparatus for filling and cleaning a pulp tower
US8409402B2 (en) 2006-09-07 2013-04-02 Sulzer Pumpen Ag Method and apparatus for filling and cleaning a pulp tower
CN105780573A (zh) * 2016-04-14 2016-07-20 华南理工大学 一种中浓浆泵立管液位自动调节方法
CN105780573B (zh) * 2016-04-14 2017-11-07 华南理工大学 一种中浓浆泵立管液位自动调节方法

Also Published As

Publication number Publication date
FI971330A0 (fi) 1997-04-01
FI118130B (fi) 2007-07-13
FI971330A (fi) 1998-10-02
AU6732898A (en) 1998-10-22

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