WO1997001667A1 - Blanchiment de pate lignocellulosique avec de l'ozone et un peracide - Google Patents

Blanchiment de pate lignocellulosique avec de l'ozone et un peracide Download PDF

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Publication number
WO1997001667A1
WO1997001667A1 PCT/SE1996/000882 SE9600882W WO9701667A1 WO 1997001667 A1 WO1997001667 A1 WO 1997001667A1 SE 9600882 W SE9600882 W SE 9600882W WO 9701667 A1 WO9701667 A1 WO 9701667A1
Authority
WO
WIPO (PCT)
Prior art keywords
ozone
pulp
bleaching
peracid
ptp
Prior art date
Application number
PCT/SE1996/000882
Other languages
English (en)
Inventor
Göran ANNERGREN
Maria Boman
Rolf Boman
Solveig Norden
Original Assignee
Sunds Defibrator Industries Ab
Sca Graphic Research Ab
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 Sunds Defibrator Industries Ab, Sca Graphic Research Ab filed Critical Sunds Defibrator Industries Ab
Priority to AU63255/96A priority Critical patent/AU6325596A/en
Publication of WO1997001667A1 publication Critical patent/WO1997001667A1/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
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone
    • 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
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/166—Bleaching ; Apparatus therefor with per compounds with peracids

Definitions

  • the present invention relates to a method of bleaching lignocellulosic fiber material in a combination step with ozone and peracid, such as peracetic acid, Z HC Paa MC .
  • the invention preferably is directed to the bleaching of sulphate pulp.
  • the pulp is treated with ozone in an HC step in an ozone reactor, where after the pulp is diluted with water or white water, and peracid is added prior to a MC bleaching tower, with subsequent washing.
  • ozone has recently been introduced as a bleaching chemical at the bleaching of pulp, in order to minimize the use of bleaching chemi- cals, and, respectively, to increase the bleaching with ⁇ out using chlorine chemicals by using a strong delignifi- cation chemical.
  • ozone is a costeffective complement to other chemicals in bleaching sequences, in which no chlorine chemicals are used. It is difficult by these sequences to achieve long range bleaching without serious carbohydrate degradation, which deteriorates the strength of the fiber material .
  • Ozone on the whole, causes considerable degra ⁇ dation, which distributes itself between moderate direct carbohydrate degradation and alkali sensitivity, due to the introduction of carbonyl groups into the cellulosa, which causes rapid degradation in a subsequent alkaline step. Due to the alkali sensitivity, the value obtained at the viscosity analysis is lower than what corresponds to real polymerisation degree of the carbohydrate mate ⁇ rial. The higher real polymerisation degree is determined simply by a boron hydride reduzzy of the pulp before the viscosity analysis. The total degradation in the ozone step would be reduced substantially, if boronhyd- ride steps are introduced into the bleaching sequence after the ozone step.
  • the costeffective de ⁇ lignification of ozone has been combined with a treatment with a small amount of peracid, which was found to sub ⁇ stantially reduce the alkali instability caused by the initial ozone treatment of the pulp.
  • the intention builds on the fact that the combination step can be adapted to the apparatur solution, which was presented for HC ozone steps, see USA 5 181 989.
  • relati ⁇ vely limited peracid treatment which is a prerequisite of the actual combination step, can be carried out in the normal treatment volume for more diluted pulp, in order to extract soluble lignin at slightly increased pH and, respectively, to treat the pulp with chelating agent in, order to remove disturbing transition metals after the ozone reactor, see patent SE 501 836.
  • Such combination step involves the difficulty that the ozone treatment must be carried out at low tem- perature and low pH, preferably 2-3, in order to be se ⁇ lective, while the peracid treatment requires a relati ⁇ vely high temperature and a higher pH, preferably 4-6.
  • the combination step which is carried out in a HC ozone step with subsequent dilution to a MC system, requires smaller amounts of peracid, because the emphasis is put on the ozone, it has been possible to adapt the conditions to existing HC ozone step equipment.
  • Figure 1 describes the system for this combina ⁇ tion step.
  • the apparatus equipment is entirely identical with that of a simple HC ozone step, with the exception of the charging equipment for peracid.
  • Figure 1 includes ozone equipment 2, peracid charging equipment 3, a first press 1 and a second press 4.
  • Figures 2 and 3 illustrate the liquid and tempe ⁇ rature balance according to the conditions used according to the invention.
  • Figures 4 and 5 show the effect of the kappa numbers (which illustrate the lignin content in the pulp) and, respectively, the effect on the pulp viscosity, both directly on the pulp and after a boron hydride reduction of the pulp.
  • the ozone treatment takes place at a pulp con ⁇ centration of > 35% and a temperature somewhere between 20 and 60°C. This is a compromise between selectivity requirements, which are furthered by a very low tempera- ture, and to cool the hot white water, without seriously deteriorating the washing efficiency etc.
  • the ozone reac ⁇ tion is extremely rapid and, therefore, the dwell time in the ozone reactor is only one or a few minutes .
  • the pulp is diluted with hot water of a higher pH to a pulp con- centration of about 12%, and peracid is added. After a dwell time in a vessel of between 10 and 30 minutes, the pulp is washed.
  • the peracetic acid yields a smaller, but more selective delignification contribution and substantially decreased alkali sensitivity, which at normal viscosity analysis, see Figure 5, yields an increased pulp visco- sity, especially when the pulp is not boron hydride re ⁇ prised before the analysis.

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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 de blanchiment de matière fibreuse lignocellulosique, dans une opération combinée, avec de l'ozone et un peracide tel que l'acide peracétique ZHCPaaMC. L'invention s'applique de préférence au blanchiment de pâte au sulfate. La pâte est traitée à l'ozone, dans une opération HC exécutée dans un réacteur à ozone, après quoi elle est diluée avec de l'eau ou de l'eau blanche, et du peracide est ajouté avant qu'elle entre dans une tour de blanchiment MC, et subisse un lavage.
PCT/SE1996/000882 1995-06-29 1996-07-01 Blanchiment de pate lignocellulosique avec de l'ozone et un peracide WO1997001667A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU63255/96A AU6325596A (en) 1995-06-29 1996-07-01 Bleaching of lignocellulosic pulp with ozone and peracid

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9502365-1 1995-06-29
SE9502365A SE506480C2 (sv) 1995-06-29 1995-06-29 Blekning av lignocellulosahaltigt fibermaterial med ozon och persyra i ett kombinationssteg

Publications (1)

Publication Number Publication Date
WO1997001667A1 true WO1997001667A1 (fr) 1997-01-16

Family

ID=20398792

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1996/000882 WO1997001667A1 (fr) 1995-06-29 1996-07-01 Blanchiment de pate lignocellulosique avec de l'ozone et un peracide

Country Status (3)

Country Link
AU (1) AU6325596A (fr)
SE (1) SE506480C2 (fr)
WO (1) WO1997001667A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998023811A1 (fr) * 1996-11-26 1998-06-04 Oy Keskuslaboratorio - Centrallaboratorium Ab Blanchiment de pate a papier cellulosique a l'aide d'ozone et de peracide
WO1999032710A1 (fr) * 1997-12-19 1999-07-01 Kemira Chemicals Oy Blanchiment de pate chimique avec du peracide
KR100228740B1 (ko) * 1997-06-30 1999-11-01 차동천 고수율기계펄프의 표백방법

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992021814A1 (fr) * 1991-06-06 1992-12-10 Solvay Interox Procede pour blanchiment et la delignification de pates a papier chimiques
FR2692917A1 (fr) * 1992-06-30 1993-12-31 Air Liquide Procédé de blanchiment d'une pâte papetière chimique.

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992021814A1 (fr) * 1991-06-06 1992-12-10 Solvay Interox Procede pour blanchiment et la delignification de pates a papier chimiques
FR2692917A1 (fr) * 1992-06-30 1993-12-31 Air Liquide Procédé de blanchiment d'une pâte papetière chimique.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998023811A1 (fr) * 1996-11-26 1998-06-04 Oy Keskuslaboratorio - Centrallaboratorium Ab Blanchiment de pate a papier cellulosique a l'aide d'ozone et de peracide
KR100228740B1 (ko) * 1997-06-30 1999-11-01 차동천 고수율기계펄프의 표백방법
WO1999032710A1 (fr) * 1997-12-19 1999-07-01 Kemira Chemicals Oy Blanchiment de pate chimique avec du peracide

Also Published As

Publication number Publication date
SE506480C2 (sv) 1997-12-22
SE9502365D0 (sv) 1995-06-29
AU6325596A (en) 1997-01-30
SE9502365L (sv) 1996-12-30

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