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WO1996009433A1 - Procede de lavage de la pate a papier - Google Patents

Procede de lavage de la pate a papier Download PDF

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Publication number
WO1996009433A1
WO1996009433A1 PCT/US1995/011635 US9511635W WO9609433A1 WO 1996009433 A1 WO1996009433 A1 WO 1996009433A1 US 9511635 W US9511635 W US 9511635W WO 9609433 A1 WO9609433 A1 WO 9609433A1
Authority
WO
WIPO (PCT)
Prior art keywords
stock
washer
pulp
thickener
consistency
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
PCT/US1995/011635
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English (en)
Inventor
Terry L. Bliss
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Black Clawson Co
Original Assignee
Black Clawson Co
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 Black Clawson Co filed Critical Black Clawson Co
Publication of WO1996009433A1 publication Critical patent/WO1996009433A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21D—TREATMENT OF THE MATERIALS BEFORE PASSING TO THE PAPER-MAKING MACHINE
    • D21D1/00—Methods of beating or refining; Beaters of the Hollander type
    • D21D1/20—Methods of refining
    • D21D1/40—Washing the fibres
    • 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
    • D21C5/00—Other processes for obtaining cellulose, e.g. cooking cotton linters ; Processes characterised by the choice of cellulose-containing starting materials
    • D21C5/02—Working-up waste paper
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/64—Paper recycling

Definitions

  • This application pertains to a system and method for washing paper making stock containing, or consisting entirely of, recycled paper products employing a combination of mat-forming thickeners or filters to increase stock consistency, with low loss of fines in combination with a high-turbulence, belt-type pulp washer.
  • Certain belt-type washers have been found useful and effective for washing and de-inking papermaking stocks which contain waste paper products.
  • these washers may be referred to as high turbulence washers.
  • a headbox delivers the paper stock to be washed or thickened between a porous belt and the closed outer surface of a roll.
  • belt or "porous belt” is used herein as a generic term to cover various kinds of porous moving supports used or which may be used for high turbulence thickeners, including woven and non-woven porous fabrics, plastic and metal belts, and the like.
  • the belt is maintained under tension and the stock is squeezed between the belt and the roll surface.
  • the stock follows the smoother roll surface and is doctored off for removal. The excess water, ash, ink and other fine particles are pressed out of the space between the belt and the roll and form the washer effluent.
  • DNT washer of The Black Clawson Company, described in U. S. Patent 4,722,793, which patent is incorporated herein by reference.
  • the DNT washer employs a two-step washing and thickening process, in which the pulp is passed between the belt and a first roll, usually called a breast roll, where it is partially dewatered, and is then carried by the belt to a second roll, usually called a couch roll. The stock is further dewatered as it passes between the belt and the couch roll.
  • the dewatered or thickened stock sometimes referred to as "accepts" is then doctored off the couch roll at the off-running side and removed for further processing, and the "white water” effluent is gathered from a catch basin and drained from the machine.
  • High turbulence washers remove ink, minerals, and short fibers from the waste paper pulp more efficiently than do slow speed mat-forming washers such as disc filters and deckers, or mildly turbulent washers such as thickeners or screw presses.
  • slow speed mat-forming washers such as disc filters and deckers, or mildly turbulent washers such as thickeners or screw presses.
  • mildly turbulent washers such as thickeners or screw presses.
  • fines the same characteristics which make the high turbulence washers quite efficient, also results in a washing out and potential loss of short paper fibers, called "fines".
  • Fibers can be defined as fibers having a length of less than about 200 microns.
  • suspended solids includes not only clays, ash and ink, but also includes papermaking fibers, and fiber fines, as defined above.
  • fines may be undesirable for certain grades of paper, an excess loss of fines in certain cases is considered to be an economic loss, where the fines contribute to bonding and opacity, such as in certain grades of fine papers and in newsprint.
  • the wash out of excessive fines is an economical loss to a paper mill in which fines are not only tolerated, but are desired, to enhance the quality of the finished product.
  • Recirculation of fines around the clarifier back to the inlet headbox of the washer, for the purpose of controlling the rate of loss of fines, can be self- defeating.
  • the recirculation loop can quickly become loaded with fines which are then repeatedly washed out, thereby lowering the capacity of the system.
  • operating the clarifier at reduced levels of effectiveness such as with reduced levels of flocculating additives and chemicals, may selectively increase the amount of fines being removed at the expense of removing ink and other contaminants, with the obvious result of a preferential removal of the very component which is most desired to be recirculated.
  • the method and system of this invention is, in part, based upon the synergistic employment, in tandem or sequence, of a low turbulence mat-forming thickener for supplying a pre-thickened stock to a high turbulence washer, as previously described. It is important to the practice of this invention that the stock pre-thickener causes only a moderate, or preferably low, loss of suspended solids, so that at least most of the desirable fines are retained in the pre-thickened stock output.
  • Equipment which meets the requirements of pre- thickening with low loss of suspended solids and fines within a given range of consistencies include vacuum disc filters and drum-type thickeners.
  • Appropriate drum thickeners include deckers, and vacuum and pressure drum washers.
  • the consistency may be increased from the conventional stock supply input value of about 0.5% to 1.5% to an output value in the range of 4% to 15%, and this can be accomplished with little loss of suspended solids.
  • the particular outlet consistency of the pre-thickener will depend on the actual inlet consistency, the nature of the thickening apparatus and its speed of operation. Those solids which are lost are generally in the 2-30 micron range as distinguished from the "fines" range or size, as previously defined, due in part to the self-filtering formation of a pulp mat which forms on the filtering or separating surfaces.
  • Effluent taken from this first thickening step may be advantageously used to re-dilute the thickened pulp from its high outlet consistency down to an intermediate but still high consistency in excess of 1.5% and as high as 3% to 6%, for application to the inlet headbox of a high turbulence washing device.
  • the high turbulence washer should have a belt speed in excess of 3,000 ft./min. and as high as 6,000 ft./min. or more.
  • the washing of pre-thickened stock in such a high turbulence device, at high belt speed, has been shown to provide a substantial increase in yield while maintaining about the same final pulp brightness as obtained in conventional practice.
  • the increase in yield primarily consists of retained fines which would otherwise be lost when operating at conventional inlet consistencies of 1.5% or less.
  • the amount of fines in the retained solids may advantageously be controlled by controlling the amount of washer effluent which is permitted to bypass the clarifier and return to the process.
  • the operator is given the choice of adjusting the overall yield and washing effectiveness over a wide range, simply by adjusting the set point of a consistency controller or valve positioned in an effluent inflow line between the low turbulence pre-thickener and the high turbulence washer.
  • Such an adjustment of consistency may, for example, be made in response to a change in the incoming raw material composition, to provide a different grade of final pulp, or to minimize the cost of obtaining the required final brightness by balancing washing effectiveness and yield against subsequent bleaching costs.
  • a further advantage of the system and method of this invention resides in the fact that in addition to yield improvements, increasing the feed consistency to a high turbulence washer has the effect of increasing the through-put capacity of the system. Likewise, the capacity of the high turbulence washer is significantly increased by increasing its feed consistency and by increasing its belt speed. A much smaller clarifier is then needed to handle the overflow of white water effluent from the high turbulence washer, and less sludge thickening capacity is required. These provide savings in the process equipment costs which offset at least in part the added costs of the pre-thickener.
  • the raw material costs may be lowered by using the process of this invention, and the overall operating costs of the method may be reduced, when it is considered that operation of the system results in lower sludge- thickening and disposal costs.
  • the operating costs for the systems according to the method of this invention are lower for the cost of sludge thickening and disposal than are conventional washing and thickening systems.
  • a pre- thickener which, in its operation, is characterized by a very low loss of fines, is used for the purpose of supplying a pre-thickened papermaking stock to a second washer, characterized as a high turbulence washer, which, when operated using stock of conventional consistencies, would be accompanied by a loss of fines in the white water and therefore a reduction in overall yield.
  • the loss of fines is offset by operating such a high turbulence washer at uncommonly high inlet consistencies, usually accompanied by operating the washer at uncommonly higher speeds, with the end result that the washed and thickened stock retains much of its fines content at a brightness which compares favorably with that which is obtained in conventional practice.
  • the method practiced by the invention for washing ash and other small suspended solids from paper maker stock, in which the stock has a large proportion of waste paper products including a fines content is characterized by the steps of applying the stock to be washed to a low turbulence thickener for extracting a portion of the water content to form a pre-thickened pulp having a consistency in the range of about 4% to 20%, diluting the pre-thickened pulp with water to a consistency which exceeds 1.5%, applying the re-diluted pulp to an inlet of a high turbulence-type pulp washer which uses a closed loop belt and which has a belt speed greater than 1200 ft./min., and then removing the thickened pulp from the high turbulence-type pulp washer with a major portion of the fines retained in the thickened pulp.
  • an apparatus or system for washing ash, ink, and other suspended solids from paper making stock which is, in part, made up of waste paper products and which includes ink, ash, and fines while still retaining a major proportion of the fines content in the washing process
  • the system including both a low turbulence paper stock thickener and a high turbulence belt-type washer, characterized by the thickening or pre-thickening of the stock in the stock thickener to a range of about 40% to 20%
  • the system and apparatus include means for applying a portion of the effluent from the thickener for re- diluting the pulp to a lower consistency which exceeds
  • Fig. 1 is a process diagram showing typical conventional practice in the employment of a high turbulence washer
  • Fig. 2 is a process diagram of a two-stage thickener/washer in accordance with this invention.
  • Fig. 3 is a plot of stock brightness versus yield for three different feed consistencies and at five different speeds of a high turbulence stock washer according to the data of Tables 1, 2 and 3 herein.
  • a high speed, high turbulence type of washer 10 is fed a slurry of paper pulp and water.
  • the white water effluent from the washer is directed to a clarifier 12.
  • a portion may be shunted around the clarifier by a bypass line 13.
  • the overflow from the clarifier 12 and the water from the bypass line 13 are recirculated into the process, while the underflow is directed to a sludge press 15 for disposal, typically in a landfill.
  • the pulp accepts output 16 from the high speed, high turbulence washer is washed pulp at a consistency of about 8% to 14% and is ready for further processing or use.
  • a washer output 16 is assumed to be 400 dry tons a day at 12.9% solids.
  • a difficult waste product such as offset printed newspaper (ONP) 70%, magazines (OMG) 30%, typically having a high ash content of about 10% as well as a high fines content
  • this typical washing setup could result in as much as a 33% loss of suspended solids in the form of ink, ash and fines, in order to provide an acceptable brightness at the accepts.
  • the washer inlet feed to the headbox on line 17 would have to be 597 dry tons a day at 1.0% consistency.
  • the washer effluent on lines 18 to the clarifier 12 is 197 dry tons a day at 0.35% solids.
  • the bypass 13 encourages a massive build ⁇ up of inks, fines, and ash within the recirculation loop and tends to apply an unacceptably high level of washed solids for recirculation. It has the effect of unbalancing consistencies, and in fact increases consistencies both to the clarifier and to the washer feed, so that these consistencies tend to move out of the optimum working range.
  • the mere quantity of solids which become entrained within the recirculation loop is a burden on the pumping and piping system and when it becomes a common practice, it results in a requirement for larger capacity pumps and larger piping.
  • clarifier bypass is a common technique in an attempt to hold down and control the total loss of solids when washing used paper pulp in a high turbulence belt- type washer/thickener 10.
  • the loss of solids and particularly the loss of fines can be reduced, according to this invention, and controlled, by first subjecting the stock to pre- thickening in a non-turbulent, mat-forming washer or thickener, usually followed by intermediate dilution and then followed by application, in a pre-thickened state, to a high turbulence type of washer of the kind previously described.
  • the inventor has discovered that a belt-type, high speed, high turbulence washer/thickener, when operated at high speed and at high inlet consistencies, has the ability of providing the required increase in brightness accompanied by a substantial retention of the fines which would otherwise be lost when operating the same machine at lower inlet consistencies and at lower speeds. This fact is demonstrated by the chart of Fig. 3 on which is plotted thirty test runs of such a high speed, high turbulence belt-type washer/thickener of the "DNT" type constructed generally in accordance with the disclosure of U. S. patent No. 4,722,793, previously mentioned.
  • Table No. 1 herein shows the test conditions in which a prepared paper stock consisting of 70% old newsprint (ONP) and 30% old magazines (OMG) was applied at just over 3% consistency to the headbox of such a washer operating at speeds ranging from 2,000 feet per minute to 6,000 feet per minute.
  • the brightness was measured according to the G.E. method, also known as the TAPPI Official Method T452om-92, and the beginning brightness was 47%.
  • Table No. 2 represents a series of runs in which the same stock was applied at a 2% feed consistency, all other conditions remaining the same. However, it may be noted that the G.E. brightness of the more diluted stock prior to washing, was slightly reduced to 46.1%.
  • Table No. 3 represents a third series of tests in which the same stock material, now diluted to just under 1% consistency, was applied to the same machine under the same conditions of belt speed ranging from 2,000 to 6,000 feet per minute, although at this further reduced consistency, the G.E. brightness of the original stock had reduced slightly to 45.7%.
  • Tables 1, 2 and 3 further respectively show the percentage of solids loss. Solids loss is the complement of yield, and is translated to percent yield in Fig. 3. Therefore, on the chart of Fig. 3, there has been plotted markers identifying each of the three sets of runs corresponding to Tables 1, 2 and 3.
  • the runs of Table No. 1 are represented in Fig. 3 by square markers.
  • the runs of Table No. 2 are represented by triangular markers, while the runs described in Table No. 3 are represented by dots.
  • These three sets of runs are plotted on the chart of Fig. 3 in which the percent of brightness is represented by the ordinate and the percentage of yield (the complement of solids loss) is represented by the abscissa.
  • Suitable non-turbulent mat-forming thickeners for this purpose include gravity deckers, vacuum drums, and disc-type filters. Such suitable disc filters are sold under the trade name "Center Disc” of Cellico, Inc. of Lawrenceville, Georgia, or “Polydisc” of Beloit Corporation, Pittsfield, Massachusetts. Further mat- forming thickeners which have low loss of fines are sold under the names "Chemi-Washer” and “Flex-D” by The Black Clawson Company of Middletown, Ohio.
  • Deckers, drum filters and disc filters are all characterized by the forming of a mat of pulp on a belt surface, providing some washing action which removes a certain portion of the ink and ash, but which retain a large percentage of the fines in the fiber mat, for delivery to the washer 10.
  • the pre-thickener effluent, on line 22, is a relatively clear water and is, in fact, much clearer than the white water effluent from the washer 10 and/or the overflow clarified effluent from the clarifier 12. It is at least partially reused in the process for re-dilution, and is adjustably or variably applied through a controllable valve 23 to the output line 21 for partial re-dilution of the pre-thickened stock to an input range, on the washer input line 17 to what is normally- considered to be an extremely high consistency input for such a washer, in the range of about 3% to 6%.
  • Fig. 2 shows the same clarifier 12 and sludge press 15 which had been illustrated in the system diagram of Fig. 1, except since the percentage of yield is improved, smaller and less expensive components may be used at these positions than have heretofore been possible.
  • the clarified or partially clarified overflow effluent from the clarifier on line 16 is also reused in this process, and the underflow clarifier sludge is delivered to the press 15.
  • the invention allows a system operator the choice of adjusting system yield and washing effectiveness over a wide range. This may be accomplished by adjusting the set point of a consistency controller 23 which controls a consistency transmitter 24 in the line between the pre- thickener 20 and the washer 10.
  • the controller 23 and transmitter 24 in turn regulate the valve position of a pre-thickener effluent dilution valve 25 or a high turbulence dilution valve 26, or both, to control or vary the amount of pre-thickener and/or high turbulence washer effluent applied to line 22 between the pre-thickener 20 and the washer 10.
  • consistency controllers and transmitters are well known in the stock preparation industry. Consistency adjustments could be made in response to a change in incoming raw material composition, such as for the purpose of producing a different final grade of pulp, or for the purpose of minimizing the costs of obtaining a final required brightness and yield loss against known bleaching costs. For these reasons, the apparatus and method of this invention provide an operator with a wider range of capabilities.
  • the invention has further versatility in having provision by which the feed to the high turbulence waster 10 may be preferentially diluted either with partially clarified cloudy white water directly from the washer itself.
  • This selection may be provided through bypass line 13 or line 13a by which the unclarified effluent may be selectively redirected to the inlet of the washer 10.
  • the latter arrangement may be preferred, in some instances, in order to keep the fines content and the flow volume to the clarifier low. Also, such an arrangement has the tendency of retaining the fines content within the high turbulence washer loop and keeping this loop both small and tight.
  • the invention in its broader sense, may be considered as a method of thickening and washing by using a thickener which is characterized by retention of fines and solids and then washing the pre-thickened pulp in a washer which has a high capacity for removing the solids, and operating such washer in such a manner that a substantial portion of the fines are retained.
  • the high turbulence, high speed belt-type thickener such as the DNT washer previously described, should be operated at or near its high speed limit.
  • this limit was somewhat in excess of 6,000 feet per minute.
  • the invention should not be construed as being limited to this speed, as the concepts herein described and the advantages which have been obtained, could be further improved by operating the thickener 10 at speeds in excess of 6,000 feet per minute. Lower speeds, of course, may be used where less brightness gain may be tolerated, with an accompanying higher yield.

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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 dispositif de lavage de la pâte de papeterie constituée de produits papetiers de récupération au milieu desquels des particules solides et des fibres courtes indésirables sont en suspension. Le procédé consiste à épaissir la pâte sur un épaississeur (20) basse turbulence pour former un matelas. Au niveau de cet épaississeur, très peu des fibres courtes sont perdues. Le procédé consiste ensuite à rediluer la pâte provenant du pré-épaississage, et à envoyer la pâte rediluée à l'entrée de la caisse de tête d'une pile laveuse (10) haute turbulence à bande pour éliminer par lavage les corps solides indésirables, tout en conservant une grande partie des fibres courtes contenues dans la pâte lavée. La vitesse de défilement de la bande de la pile laveuse atteint au moins 6.000 pieds par minute. L'eau claire de rejet du pré-épaississeur sert à la redilution, et une partie de l'eau blanche rejetée par la pile laveuse haute turbulence à bande peut être directement réinjectée dans l'admission d'eau, ou bien la réinjection peut ne porter que sur une partie éclaircie de cette eau blanche, ou sur une combinaison des deux.
PCT/US1995/011635 1994-09-20 1995-09-14 Procede de lavage de la pate a papier Ceased WO1996009433A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US30897794A 1994-09-20 1994-09-20
US08/308,977 1994-09-20

Publications (1)

Publication Number Publication Date
WO1996009433A1 true WO1996009433A1 (fr) 1996-03-28

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Application Number Title Priority Date Filing Date
PCT/US1995/011635 Ceased WO1996009433A1 (fr) 1994-09-20 1995-09-14 Procede de lavage de la pate a papier

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001007711A1 (fr) * 1999-07-22 2001-02-01 Metso Paper Inc. Procede et appareil de lavage de melange de pulpe fibreuse
DE102006057861A1 (de) * 2006-12-08 2008-06-12 Voith Patent Gmbh Verfahren zur Behandlung von beim Eindicken von Papierfasersuspension anfallendem Filtrat

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4686005A (en) * 1980-02-06 1987-08-11 Escher Wyss Gmbh Method of washing stock suspensions by removing undesired material through an endless revolving wire
US4722793A (en) * 1986-07-03 1988-02-02 The Black Clawson Company Apparatus and method for thickening pulp and paper stock

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4686005A (en) * 1980-02-06 1987-08-11 Escher Wyss Gmbh Method of washing stock suspensions by removing undesired material through an endless revolving wire
US4686005B1 (en) * 1980-02-06 1995-10-17 Escher Wyss Gmbh Method of washing stock suspensions by removing undesired material through an endless revolving wire
US4722793A (en) * 1986-07-03 1988-02-02 The Black Clawson Company Apparatus and method for thickening pulp and paper stock

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CPPA, 80TH ANNUAL MEETING TECHNICAL SECTION, Montreal, Canada, February 2-4, 1994, LAFRENIERE et al., "Recycled Pulp Washing", Part 1, Comparison of Washing Equipment and Sub-Systems, pp. A315-A326. *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001007711A1 (fr) * 1999-07-22 2001-02-01 Metso Paper Inc. Procede et appareil de lavage de melange de pulpe fibreuse
US6302996B1 (en) 1999-07-22 2001-10-16 Metso Paper, Inc. Method and apparatus for washing fiber pulp mixture
JP2003505611A (ja) * 1999-07-22 2003-02-12 メトソ ペーパ インコーポレイテッド 繊維パルプ混合物の洗浄方法および装置
KR100685759B1 (ko) * 1999-07-22 2007-02-27 메트소 페이퍼 인크. 섬유 펄프 혼합물을 세척하는 방법 및 장치
DE102006057861A1 (de) * 2006-12-08 2008-06-12 Voith Patent Gmbh Verfahren zur Behandlung von beim Eindicken von Papierfasersuspension anfallendem Filtrat

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