EP0547100B1 - Herstellungsverfahren von lignozellulosischem zellstoff und vorrichtung zur durchführung des verfahrens - Google Patents

Herstellungsverfahren von lignozellulosischem zellstoff und vorrichtung zur durchführung des verfahrens Download PDF

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Publication number
EP0547100B1
EP0547100B1 EP91915560A EP91915560A EP0547100B1 EP 0547100 B1 EP0547100 B1 EP 0547100B1 EP 91915560 A EP91915560 A EP 91915560A EP 91915560 A EP91915560 A EP 91915560A EP 0547100 B1 EP0547100 B1 EP 0547100B1
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EP
European Patent Office
Prior art keywords
washing
treatment
enzyme
pulp
stock
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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.)
Expired - Lifetime
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EP91915560A
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English (en)
French (fr)
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EP0547100A1 (de
Inventor
Lars Saaby Pedersen
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Novo Nordisk AS
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Novo Nordisk AS
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    • 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
    • D21C5/005—Treatment of cellulose-containing material with microorganisms or enzymes
    • 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

Definitions

  • a common stage in the treatment of wood chips for paper production is chemical pulping, e.g. the so-called kraft process which is an alkaline sulphate cooking of the wood chips.
  • the native wood chips contain around 30% lignin, and at the end of the chemical cooking process less than 5% of the lignin compounds is still left in the pulp. Due to the strong brown color of the remaining lignin and its tendency to darken in UV light or by oxidation this has to be removed in order to obtain a white pulp without the tendency to color reversion.
  • After the sulphate cooking a multistage washing of the unbleached kraft brown stock takes place. The well washed brown stock can then be treated with an enzyme preparation followed by a subsequent wash before entering the bleach plant.
  • the invention comprises an improvement of this conventional multistage washing of the unbleached kraft brown stock, followed by the enzyme treatment with the subsequent wash, whereby this improvement is a modification, which improves the economy and facilitates the processing.
  • the brown color can be removed by a multistage bleaching using e.g. chlorine and/or chlorine dioxide.
  • a multistage bleaching using e.g. chlorine and/or chlorine dioxide. Due to the ever increasing environmental concern, the dosage of chlorine and/or chlorine dioxide has to be kept at a minimum, and it is for that reason that the enzymatic treatment of the kraft cooked pulp has been introduced, vide e.g. The third International Conference on Biotechnology in the Pulp and Paper Industry, Swiss, 16-19.6, 1986, page 67-69.
  • the invention comprises the above indicated processes 2) and 3) and is an improvement thereof, as explained in more detail in the following.
  • the purpose of the invention is the provision of a process for treatment of lignocellulosic pulp which requires a less expensive apparatus or stated otherwise the provision of a reduction of the price of the prior art method for treatment of lignocellulosic pulp comprising a multistage washing of the unbleached brown kraft stock with subsequent enzyme treatment, washing and bleaching, and a corresponding apparatus for performance of the process.
  • the purpose of the invention can be fulfilled, if the enzymatic treatment with the subsequent wash is abandoned altogether and the enzymatic treatment is introduced between two brown stock washing units in the multistage washings of the unbleached kraft brown stock, or stated otherwise if the enzyme treatment is introduced upstream the prior art position of the enzyme treatment in the multistage washing, in such manner that the multistage washing for washing out of impurities from the kraft cooking and washing out of the residues from the enzyme treatment is combined.
  • the process for treatment of lignocellulosic pulp according to the invention comprising a multistage washing of the unbleached kraft brown stock and a treatment with a xylanase with high pH activity and stability and high heat stability is characterized by the fact that the xylanase treatment is introduced between two brown stock washing units in such manner that the washed stock from the outlet side of one or more of the washing units is transported to a holding tank, that the xylanase with high pH activity and stability and high heat stability is added directly upstream the holding tank, and that the enzyme treated stock is passed further on in the process to the next washing unit.
  • another non-chlorine bleaching stage e.g. an oxygen delignification stage or an ozone stage may be included either before or after the enzyme stage.
  • Fig. 1 prior art
  • Fig. 2 invention
  • the invention requires one washing unit less than the prior art process, and thus, the process according to the invention fulfils the purpose of the invention.
  • the tank on Fig. 1 used for the enzyme treatment normally also serves as buffer tank between the kraft cooking and the bleaching plant the residence time of the pulp in the tank often varies within a wide range, e.g. between 30 minutes and 24 hours.
  • the tank is an integrated part of the washing process. It only serves the need for holding time for the enzyme treatment, which makes it much easier to control the enzyme treatment time.
  • the invention provides a much better connection to the existing wash water streams.
  • wash water obtained in the process according to the invention will end up in the recovery system for the kraft cooking process, which means that everything that is solubilized during the enzyme treatment will be burned in the recovery boiler whereby the BOD5 load from the enzyme stage on the effluent streams is eliminated.
  • the wash water from the washing stage after the enzyme treatment normally has to be sewered.
  • the enzyme treatment according to the invention also releases more cooking chemicals from the pulp than a conventional wash with water. This makes it possible to obtain an even better recovery of cooking chemicals than normally obtained.
  • the three washing units on Fig. 2 are not limiting to the invention, but just an example. Each single unit can represent more than one washing stage. With three washing units one, two or three enzyme treatment units can be introduced according to the invention; just one enzyme treatment unit is shown on Fig. 2.
  • the invention comprises an apparatus for performance of the process according to the invention.
  • the apparatus according to the invention is characterized by the fact that a holding tank with piping with facilities for introduction of enzyme is introduced downstream one or more of the washing units except for the last washing unit, that piping is provided for further transport of the stock to the next washing unit, and that the conventional enzyme treatment unit downstream the washing unit is abandoned.
  • the pulp P was diluted with fresh water to a consistency of 1% DS and then reconcentrated to a consistency of approximately 20% on a wire screen.
  • This washing sequence is the standard washing stage used throughout this example.
  • This pulp sample was divided into two halves.
  • EXU xylanase activity unit appears from AF 293.9/1, obtainable on request from NOVO NORDISK A/S, Novo Allé, DK-2880 Bagsvaerd, Denmark.
  • the xylanase stage was carried out as follows.
  • the pulp was diluted to the desired consistency by addition of fresh water.
  • the enzyme solution was added and mixed into the pulp by vigorous mixing.
  • the pulp was then placed in a water bath to ensure constant temperature for the remainder of the treatment time. The pulp was not mixed during the three hours of holding time.
  • pulp sample which was enzyme treated between the first and the second washing stage, was carried out according to the invention and will be referred to later as inv 1-2 .
  • the second half of the one stage washed pulp was carried through another standard washing stage. After washing the pH of the pulp suspension was 8.7.
  • the enzyme treatment was carried out as described above.
  • FXU xylanase activity unit appears from AF 293.6/1, obtainable on request from NOVO NORDISK A/S, Novo Allé, DK-2880 Bagsvaerd, Denmark.
  • the enzyme treatment was made as described above.
  • the xylanases used in this example were selected according to their pH optimum in relation to the pH of the pulp.
  • the bleachings were carried out under the following conditions:
  • Kappa number of the pulps after the (D50 C50) E bleachings Kappa number delta Kappa number % Control 2.85 - Prior 2.52 11.6 inv 1-2 2.50 12.3 inv 2-3 2.31 19.0

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  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Biochemistry (AREA)
  • Microbiology (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)
  • Chemical And Physical Treatments For Wood And The Like (AREA)

Claims (2)

  1. Verfahren zur Behandlung von lignocellulosischem Faserbrei, umfassend ein mehrstufiges Waschen von ungebleichtem braunem Kraftpapierrohstoff und eine Behandlung mit einer Xylanase mit einer Aktivität und Stabilität bei hohem pH-Wert und einer hohen Wärmestabilität, gekennzeichnet durch die Tatsache, daß die Xylanasebehandlung zwischen zwei Wascheinheiten des braunen Papierrohstoffs in einer solchen Weise eingeführt wird, daß der gewaschene Papierrohstoff von der Auslaßseite einer oder mehrerer Wascheinheiten in einen Lagertank transportiert wird, daß die Xylanase mit einer Aktivität und Stabilität bei hohem pH-Wert und einer hohen Wärmestabilität direkt stromaufwärts von dem Lagertank zugegeben wird und daß der mit dem Enzym behandelte Papierrohstoff im Verfahren weiter zur nächsten Wascheinheit geleitet wird.
  2. Vorrichtung zur Durchführung des Verfahrens nach Anspruch 1, gekennzeichnet durch die Tatsache, daß ein Lagertank mit Rohrleitungen mit Einrichtungen zur Einführung von Enzym stromabwärts von einer oder mehreren Wascheinheiten mit Ausnahme der letzten Wascheinheit eingeführt wird, daß Rohrleitungen zum weiteren Transport des Papierrohstoffs zum nächsten Waschtank bereitgestellt werden und daß die herkömmliche Enzymbehandlungseinheit stromabwärts von der Wascheinheit weggelassen wird.
EP91915560A 1990-08-24 1991-08-21 Herstellungsverfahren von lignozellulosischem zellstoff und vorrichtung zur durchführung des verfahrens Expired - Lifetime EP0547100B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DK2034/90 1990-08-24
DK203490A DK203490D0 (da) 1990-08-24 1990-08-24 Fremgangsmaade til behandling af lignocellulosepulp og apparat til udfoerelse af processen
PCT/DK1991/000239 WO1992003608A1 (en) 1990-08-24 1991-08-21 Process for treatment of lignocellulosic pulp and apparatus for performance of the process

Publications (2)

Publication Number Publication Date
EP0547100A1 EP0547100A1 (de) 1993-06-23
EP0547100B1 true EP0547100B1 (de) 1995-02-22

Family

ID=8109613

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91915560A Expired - Lifetime EP0547100B1 (de) 1990-08-24 1991-08-21 Herstellungsverfahren von lignozellulosischem zellstoff und vorrichtung zur durchführung des verfahrens

Country Status (11)

Country Link
EP (1) EP0547100B1 (de)
JP (1) JPH05509137A (de)
AT (1) ATE118842T1 (de)
BR (1) BR9106763A (de)
CA (1) CA2090338A1 (de)
DE (1) DE69107620D1 (de)
DK (1) DK203490D0 (de)
ES (1) ES2069307T3 (de)
FI (1) FI930803A0 (de)
NZ (1) NZ239501A (de)
WO (1) WO1992003608A1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
MXPA03011194A (es) 2001-06-06 2004-02-26 Novozymes As Endo-beta-1,4-glucanasa.
CN101967490B (zh) 2002-06-14 2014-07-16 先正达公司 木聚糖酶、编码木聚糖酶的核酸以及制备和应用它们的方法
DK1989302T3 (en) 2006-02-14 2018-07-23 Bp Corp North America Inc XYLANASES, NUCLEIC ACID CODING THEM AND PROCEDURES FOR THEIR PREPARATION AND USE
WO2009073709A1 (en) 2007-12-06 2009-06-11 Novozymes A/S Polypeptides having acetylxylan esterase activity and polynucleotides encoding same
DK2483403T3 (en) 2009-09-29 2018-02-12 Novozymes Inc POLYPEPTIDES WITH XYLANASE ACTIVITY AND POLYNUCLEOTIDES CODING THEM
CA2780198A1 (en) 2009-11-06 2011-05-12 Novozymes, Inc. Polypeptides having xylanase activity and polynucleotides encoding same

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0373107B1 (de) * 1988-11-23 1994-03-23 Sandoz Ag Benutzung von Enzymen von Aureobasidium Pullulans für das Bleichen von Zellstoff
FI90888B (fi) * 1989-02-14 1993-12-31 Enso Gutzeit Oy Menetelmä selluloosamassan valkaisemiseksi

Also Published As

Publication number Publication date
NZ239501A (en) 1993-01-27
BR9106763A (pt) 1993-06-29
FI930803A (fi) 1993-02-23
JPH05509137A (ja) 1993-12-16
DK203490D0 (da) 1990-08-24
CA2090338A1 (en) 1992-02-25
ATE118842T1 (de) 1995-03-15
EP0547100A1 (de) 1993-06-23
FI930803A0 (fi) 1993-02-23
DE69107620D1 (de) 1995-03-30
WO1992003608A1 (en) 1992-03-05
ES2069307T3 (es) 1995-05-01

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