WO2010039092A1 - Presse de lavage pour laver une pâte à papier - Google Patents

Presse de lavage pour laver une pâte à papier Download PDF

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Publication number
WO2010039092A1
WO2010039092A1 PCT/SE2009/051072 SE2009051072W WO2010039092A1 WO 2010039092 A1 WO2010039092 A1 WO 2010039092A1 SE 2009051072 W SE2009051072 W SE 2009051072W WO 2010039092 A1 WO2010039092 A1 WO 2010039092A1
Authority
WO
WIPO (PCT)
Prior art keywords
pulp
vat
passage
washing
arrangement
Prior art date
Application number
PCT/SE2009/051072
Other languages
English (en)
Inventor
Stefan Mattsson
Magnus Danielsson
Original Assignee
Metso Paper, Inc.
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 Metso Paper, Inc. filed Critical Metso Paper, Inc.
Priority to CA2736723A priority Critical patent/CA2736723A1/fr
Priority to EP09818061.5A priority patent/EP2344694A4/fr
Priority to CN200980139748.7A priority patent/CN102171393B/zh
Publication of WO2010039092A1 publication Critical patent/WO2010039092A1/fr

Links

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
    • D21C9/02—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents
    • D21C9/06—Washing ; Displacing cooking or pulp-treating liquors contained in the pulp by fluids, e.g. wash water or other pulp-treating agents in filters ; Washing of concentrated pulp, e.g. pulp mats, on filtering surfaces
    • 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
    • D21C9/18—De-watering; Elimination of cooking or pulp-treating liquors from the pulp

Definitions

  • the present invention relates to washing of cellulose pulp and in particular to press washing with two co-operating cylindrical press rolls.
  • Pulp washing is a key operation in the chemical pulping line.
  • washers There are many different types of washers available, some of which are based on press washing and comprise means for pressing the pulp such that fluid is removed. After pressing, the pulp is normally diluted to a desired thickness.
  • a well-known type of press washer has two co-operating cylindrical press rolls, arranged with their rotation center in the same horizontal plane.
  • the outer surface of each press roll is perforated and, during operation, cellulose pulp is input to a restricted space between the perforated roll surface and a restriction member, such as a trough, whereby a pulp web is formed on the perforated roll surface.
  • the press rolls are arranged to rotate in opposite directions so as to transport the respective pulp webs in the direction of rotation to be pressed in a so-called pinch or nip where the distance between the press rolls is smallest.
  • the fluid removed from the pulp passes through the perforated roll surface in a radially inward direction and can for example be transported to the ends of the respective press roll by means of axial filtrate channels.
  • a press washer of the described general type is disclosed in US Patent 3,980,518, for example.
  • pulp is input separately to each drum and there is one pulp distribution unit (inlet box) for each drum.
  • the pulp is in US Patent 3,980,518 distributed onto the press rolls through an adjustable narrow gap.
  • Another example of a pulp distribution unit is disclosed in WO 94/10380, where pulp is deflected in a curved passage in order to supply the press rolls with a uniformly distributed and parallel flow.
  • WO 03/016618 describes an arrangement with several distribution units that are separately controlled.
  • a general object of the invention is to provide an improved arrangement for washing cellulose pulp.
  • a specific object is to achieve an improved pulp input mechanism.
  • Another object is to achieve appropriate pulp distribution and formation.
  • the present invention proposes a washing arrangement comprising a pulp inlet arranged beneath the pinch, which together with an inner and outer vat structure form a most advantageous pulp input and distribution mechanism.
  • the incoming pulp is transported through a zone for pulp distribution defined by the outer vat and thereafter formed on the roll surface and transported through a zone for dewatering and pressing (and washing) defined by the inner vat.
  • an arrangement for washing cellulose pulp comprising two press rolls with perforated outer surfaces, arranged to rotate in opposite directions during operation such that the pulp is pressed into a pinch between the press rolls, an inner vat, arranged at a distance from the perforated outer surfaces so as to partially enclose the press rolls in the circumferential direction, an inner pulp passage being formed for each press roll substantially between the perforated outer surface and the inner vat, and a pulp inlet for introducing pulp to the washing arrangement.
  • the washing arrangement further comprises an outer vat, arranged at a distance from the inner vat so as to at least partially enclose the inner vat and form an outer pulp passage for each press roll, the outer pulp passage being connected to the inner pulp passage.
  • the pulp inlet is connected to a central portion of the outer vat, whereby, in operation, pulp introduced via the pulp inlet is transported through the outer pulp passage substantially opposite the direction of rotation and thereafter through the inner pulp passage substantially in the direction of rotation before reaching the pinch.
  • Fig. 1 is a schematic transverse cross-section of a washing arrangement according to an exemplifying embodiment of the present invention
  • Fig. 2 is a schematic transverse cross-section of a washing arrangement according to another exemplifying embodiment of the present invention.
  • Fig. 3A is a schematic transverse cross-section of a washing arrangement with a pulp input unit according to still another exemplifying embodiment of the present invention.
  • Fig. 3B is a schematic and partial side view of the pulp input unit of the washing arrangement in Fig. 3A.
  • Fig. 1 is a schematic transverse cross-section of a washing arrangement according to an exemplifying embodiment of the present invention.
  • the illustrated washing arrangement 100 comprises two co-operating cylindrical press rolls/drums 110, 110', arranged to rotate in opposite directions R, R' during operation and each having a perforated outer surface 112, 112', such as a surface of perforated metal sheet.
  • the rotation centers are normally arranged in the same horizontal plane and it may often be preferred that one rotation center is fixed, whereas the other rotation center is allowed to slide somewhat.
  • the washing arrangement 100 further presents an inner vat 120, arranged at a distance from the perforated outer surfaces 112, 112' of the press rolls 110, 110' so as to partially enclose the press rolls in the circumferential direction, whereby an inner pulp passage 122, 122' is defined for each press roll between the perforated outer surface 112, 112' and the inner vat 120.
  • an outer vat 140 arranged to form an outer pulp passage 142, 142' for each press roll.
  • the outer vat 140 defines an outer wall of the respective outer pulp passage 142, 142'.
  • the pulp inlet 130 is connected to a central portion of the outer vat 140, "central” with respect to the extension of the outer vat in the circumferential direction (as seen in Fig. 1).
  • the outer pulp passage 142, 142' is connected to the pulp inlet 130 at one end and to its corresponding inner pulp passage 122, 122' at the other end.
  • the inner vat 120 and the outer vat 140 comprises non-interrupted surfaces substantially enclosing the entire inner pulp passages 122, 122' and outer pulp passages 142, 142', respectively, in the circumferential direction and covering the entire press rolls 110, 110' in a longitudinal (i.e. axial) direction.
  • the press rolls 110, 110' rotate in opposite directions R, R' and pulp fed from the pulp inlet 130 is transported through the respective outer pulp passages 142, 142' in a direction substantially opposite these rotations.
  • a pulp web (not shown) is formed on the respective perforated outer surfaces 112, 112' of the press rolls 110, 110'.
  • the pulp first comes in contact with the perforated outer surface 112, 112' at the upper portion of the respective press roll 110, 110' and the pulp web is formed "spontaneously" due to a pressure difference between the inner vat 120 and the inside of the press roll 110, 110'.
  • the pulp In the inner pulp passage 122, 122', the pulp is, guided by the inner vat 120, transported in the direction of rotation R, R' of the press rolls 110, 110' and eventually pressed in a pinch/nip 114 where the distance between the press rolls 110, 110' is smallest.
  • the inner pulp passage 122, 122' for each press roll 110, 110' is thus a space where pulp, during operation, is transported in direction of rotation substantially between the perforated outer roll surface 112, 112' and the inner vat 120 and further to the pinch 114.
  • the inner pulp passage 122, 122' extends from where the pulp, at the end of the outer pulp passage 142, 142', meets a substantially clean press roll surface to the pinch 114.
  • the inner pulp passage 122, 122' extends, in the circumferential direction, so as to, in operation, provide a pulp web on the perforated outer surface 112, 112' of about 220-270° from the beginning of the inner pulp passage to the pinch 114.
  • the angle defined by the lines intersecting the rotation center and the pinch 114 and the beginning of the inner pulp passage 122, 122', respectively, preferably lies within the interval of 220-270°.
  • the inner pulp passage 122, 122' may be converging, diverging, or parallel to the perforated outer surface 112, 112', or, alternatively, a combination of said features.
  • the illustrated press rolls 110, 110' comprise a plurality of axial filtrate channels 116, 116', arranged to receive filtrate that passes through the perforated outer surfaces 112, 112'. Filtrate is, during operation, transported through the perforated outer surfaces 112, 112' and radially inwards into the axial filtrate channels 116, 116', and thereafter typically collected and output from the washing arrangement 100, e.g. at one or both ends.
  • washing liquid is in the example of Fig. 1 supplied to the pulp web (with devices 156).
  • pulp is in this example output by means of a screw arrangement 118, which transfers the pulp to a subsequent process stage (not shown), such as a standpipe or another unit where the pulp may be diluted and processed.
  • the outer pulp passage constitutes a zone for distribution of the pulp by means of pump pressure and, as will be described below, possible also stirring at the pulp inlet.
  • the actual washing activities take place as the pulp is transported on the perforated roll surface in the inner pulp passage, which accordingly constitutes a zone for dewatering, displacement and pressing.
  • the inner pulp passage is just a zone for dewatering and pressing.
  • the beginning of the inner pulp passage may be viewed as a zone for pulp formation in the sense that this is where the pulp web is formed on the press roll.
  • the illustrated washing arrangements of Fig. 1, 2, and 3 A all disclose means for washing liquid addition arranged in connection with the inner vat 120 such that, in operation, washing liquid is added to the pulp in the inner vat 120.
  • washing liquid addition devices 156 such as nozzles, or simple apertures/holes, the washing liquid is typically distributed over the pulp web by means of a pressure difference.
  • the means for washing liquid addition includes a partitioning wall 152 arranged substantially between the inner vat 120 and the outer vat 140 such that a space for washing liquid 154 is defined by the partitioning wall 152 and the inner vat 120.
  • the space for washing liquid 154 may contain lines/pipes for the washing liquid to be added to the inner vat 120 or, alternatively, washing liquid could be flowing freely therein.
  • the space for washing liquid 154 extends, in the circumferential direction, so as to enclose at least a portion of the respective inner pulp passages 122, 122'.
  • the partition wall 152 extends between the two lowermost points of the inner vat 120, thus forming a space for washing liquid 154 enclosing only the last portion of the respective inner pulp passages 122, 122'.
  • Washing liquid is in this embodiment supplied to the pulp web at a single position per press roll 110, 110' in the circumferential direction. (In the longitudinal direction there may be a plurality of washing liquid addition points distributed axially.) hi the embodiment of Fig.
  • the space for washing liquid 154 extends, in the circumferential direction, so as to enclose substantially the entire inner pulp passage 122, 122' and comprises two washing liquid addition devices 156 per press roll, distributed circumferentially.
  • the number and position of the washing liquid addition devices 156 may of course vary and there may very well be more than two washing liquid addition devices distributed circumferentially.
  • the space for washing liquid 154 extends between the two outermost (left and right) points of the inner vat 120, thus forming a space for washing liquid 154 enclosing a substantial portion of the inner pulp passage 122, 122'.
  • the partitioning wall 152 may be integrally formed e.g. with a pulp input unit 132.
  • the partitioning wall 152 serves as an inner wall of at least a portion of the respective outer pulp passages 142, 142', the partitioning wall being a guide surface for the pulp in that portion of the outer pulp passages 142, 142'.
  • the partitioning wall 152 is then arranged such that the pulp flow does not encounter sharp edges or throttles, i.e. such that a smooth outer pulp passage 142, 142' is accomplished. The pulp distribution is thereby further improved.
  • Washing liquid addition is optional in the washing arrangement of the present invention.
  • the described feature of a partitioning wall 152 serving as a guide surface is not restricted to applications with washing liquid addition but may be useful also in pure dewatering presses. Also in such cases, the partitioning wall 152 is arranged substantially between the inner vat
  • the partitioning wall is a guide surface for the pulp in that portion of the outer pulp passage.
  • washing liquid addition may, on the other hand, also be embodiments with washing liquid addition but without the partitioning wall 152 (and the space for washing liquid 154), in which cases washing liquid is added directly to the inner vat 120.
  • a washing arrangement 100 with a pulp input unit 132 will now be described with reference to Figs. 3 A and 3B.
  • the pulp input unit 132 is arranged at the pulp inlet 130, preferably right beneath the pinch, or slightly displaced. It comprises a length distribution unit 134 extending along substantially the entire length of the press rolls 110, 110', and agitator means 138 rotatably mounted within the length distribution unit 134.
  • the length distribution unit 134 e.g.
  • a pipe parallel to the press rolls is in the example of Fig. 3B provided with a plurality of apertures 136 distributed lengthwise.
  • the apertures 136 are preferably arranged such that, in operation, the pulp enters the respective outer pulp passage 142, 142' in a direction substantially corresponding to the general pulp flow direction in the outer pulp passage 142, 142'. Accordingly, in Fig. 3 A arrows indicate that the pulp leaves the length distribution unit 134 through the apertures 136 in directions perpendicular to the length axes of the press rolls 110, 110' and the length distribution unit 134. In this way, there will be less disturbances in the pulp flow in the beginning of the outer pulp passage 142, 142' and therefore a more efficient pulp flow and a better pulp distribution can be achieved.
  • the number and shape of apertures may vary within the scope of the invention.
  • the circular holes 136 in Fig. 3B may be replaced by slots or the like.
  • the length distribution unit may be provided with a gap (i.e. one elongated aperture/opening) extending in the longitudinal direction.
  • the agitator means 138 is axially arranged within the length distribution unit. It can for example comprise a screw, a bladed shaft, a fluted shaft, a slotted shaft, a shaft with pins, or a combination of two or more of these.
  • the agitator means 138 keeps the pulp in motion so as to achieve an appropriate lengthwise pulp distribution in the washing arrangement.
  • An advantage of this solution is that the pressure drop in the pulp input unit will be low as compared to the pressure drop in prior art arrangements. Efficient pulp distribution can therefore be achieved while keeping the pump pressure at the inlet low.
  • the low pressure drop associated with the proposed pulp distribution with agitator means may also make it possible to do without orifices, or the like, which are often used in conventional pulp input arrangements.
  • the proposed pulp input unit offers a comparatively simple and cost-efficient solution.
  • Another embodiment of the present invention (not shown) comprises an "open" pulp input unit, in the sense that there is an open space between the agitator means and the outer pulp passage instead of a wall (or similar restriction) with aperture(s).
  • the agitator means would still be axially arranged in the area beneath the pinch.

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

Abstract

L'invention porte sur une presse de lavage (100) pour pâte à papier, comprenant deux rouleaux de presse perforés coopérants (110, 110'). Une cuve interne (120) est disposée à une certaine distance des rouleaux perforés, un passage de pâte interne (122, 122') étant formé pour chaque rouleau de presse entre la surface de rouleau et la cuve interne. Une cuve externe (140) est disposée à une certaine distance de la cuve interne de façon à former un passage de pâte externe (142, 142') pour chaque rouleau de presse. Une entrée de pâte est disposée en dessous du pincement (114), ce par quoi, lors du fonctionnement, une pâte introduite par l'entrée est transportée à travers le passage de pâte externe (zone pour la distribution de pâte) de façon opposée à la direction de rotation (R, R'), puis à travers le passage de pâte interne, dans la direction de rotation, avant d'atteindre le pincement. Cette presse de lavage offre une construction simple et rentable du point de vue des coûts, ainsi qu'une excellente formation de pâte.
PCT/SE2009/051072 2008-10-01 2009-09-28 Presse de lavage pour laver une pâte à papier WO2010039092A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CA2736723A CA2736723A1 (fr) 2008-10-01 2009-09-28 Presse de lavage pour laver une pate a papier
EP09818061.5A EP2344694A4 (fr) 2008-10-01 2009-09-28 Presse de lavage pour laver une pâte à papier
CN200980139748.7A CN102171393B (zh) 2008-10-01 2009-09-28 用于洗涤纤维素纸浆的压榨式洗浆机

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE0802072A SE0802072A2 (sv) 2008-10-01 2008-10-01 Tvättpress för tvättning av cellulosamassa
SE0802072-9 2008-10-01

Publications (1)

Publication Number Publication Date
WO2010039092A1 true WO2010039092A1 (fr) 2010-04-08

Family

ID=42073711

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE2009/051072 WO2010039092A1 (fr) 2008-10-01 2009-09-28 Presse de lavage pour laver une pâte à papier

Country Status (5)

Country Link
EP (1) EP2344694A4 (fr)
CN (1) CN102171393B (fr)
CA (1) CA2736723A1 (fr)
SE (1) SE0802072A2 (fr)
WO (1) WO2010039092A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023048610A1 (fr) * 2021-09-24 2023-03-30 Valmet Ab Appareil de lavage d'une pâte de cellulose

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE537341C2 (sv) * 2012-09-25 2015-04-07 Valmet Oy Vätskefördelare för en tvättningsapparat och en tvättningsapparat
CN103410037A (zh) * 2013-07-12 2013-11-27 海南金海浆纸业有限公司 双辊压榨洗浆机高压喷淋清洗装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE318182B (fr) * 1968-04-23 1969-12-01 Karlstad Mekaniska Ab
SE349075B (fr) * 1969-10-21 1972-09-18 Karlstad Mekaniska Ab
US5902456A (en) * 1994-12-12 1999-05-11 Sunds Defibrator Industries Ab Dewatering apparatus
US6311849B1 (en) * 1997-05-26 2001-11-06 Andritz-Patentverwaltungs-Gesselschaft M.B.H. Device for dehydrating and washing suspensions of fibrous material
WO2008051157A1 (fr) * 2006-10-27 2008-05-02 Metso Paper, Inc. Presse de lavage à séparation de filtrats

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE380300C (sv) * 1974-03-04 1984-10-29 Sunds Ab Anordning for vetskebehandling av en fibersuspension
SE507579C2 (sv) * 1993-09-08 1998-06-22 Sunds Defibrator Ind Ab Vätskebehandlingsanordning med skjutbar del av tråg
CN2255448Y (zh) * 1995-11-30 1997-06-04 王锡元 环网置换压榨洗浆机
CN2441845Y (zh) * 2000-09-21 2001-08-08 潍坊市轻工机械研究所 双辊置换洗浆机

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE318182B (fr) * 1968-04-23 1969-12-01 Karlstad Mekaniska Ab
SE349075B (fr) * 1969-10-21 1972-09-18 Karlstad Mekaniska Ab
US5902456A (en) * 1994-12-12 1999-05-11 Sunds Defibrator Industries Ab Dewatering apparatus
US6311849B1 (en) * 1997-05-26 2001-11-06 Andritz-Patentverwaltungs-Gesselschaft M.B.H. Device for dehydrating and washing suspensions of fibrous material
WO2008051157A1 (fr) * 2006-10-27 2008-05-02 Metso Paper, Inc. Presse de lavage à séparation de filtrats

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP2344694A4 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2023048610A1 (fr) * 2021-09-24 2023-03-30 Valmet Ab Appareil de lavage d'une pâte de cellulose

Also Published As

Publication number Publication date
SE0802072A2 (sv) 2010-07-20
SE0802072A1 (sv) 2010-04-02
EP2344694A4 (fr) 2013-07-24
CN102171393B (zh) 2013-03-27
EP2344694A1 (fr) 2011-07-20
CA2736723A1 (fr) 2010-04-08
CN102171393A (zh) 2011-08-31
SE532973C2 (sv) 2010-06-01

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