EP0960235A1 - Procede de delignification a l'oxygene de pate a papier - Google Patents

Procede de delignification a l'oxygene de pate a papier

Info

Publication number
EP0960235A1
EP0960235A1 EP98900506A EP98900506A EP0960235A1 EP 0960235 A1 EP0960235 A1 EP 0960235A1 EP 98900506 A EP98900506 A EP 98900506A EP 98900506 A EP98900506 A EP 98900506A EP 0960235 A1 EP0960235 A1 EP 0960235A1
Authority
EP
European Patent Office
Prior art keywords
pulp
reducing agent
stage
oxygen
reactor
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.)
Granted
Application number
EP98900506A
Other languages
German (de)
English (en)
Other versions
EP0960235B1 (fr
Inventor
Yonghao Ni
Adriaan R. P. Van Heiningen
Guo Jun Kang
Anastasios Skothos
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.)
University of New Brunswick
Original Assignee
University of New Brunswick
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 University of New Brunswick filed Critical University of New Brunswick
Publication of EP0960235A1 publication Critical patent/EP0960235A1/fr
Application granted granted Critical
Publication of EP0960235B1 publication Critical patent/EP0960235B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • 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
    • D21C9/1036—Use of compounds accelerating or improving the efficiency of the processes
    • 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
    • D21C9/1084—Bleaching ; Apparatus therefor with reducing compounds

Definitions

  • the present invention is concerned with a single stage process for decreasing carbohydrate degradation of sulphite pulps during the O Mg0 process by the addition of a
  • oxygen dehgnification technology uses sodium hydroxide as the alkaline source and the resulting effluent produced can therefore be incorporated into the chemical recovery system of the
  • MgO magnesium hydroxide
  • Mg OH magnesium hydroxide
  • the temperature of delignification with MgO or Mg(OH) 2 must be about 30°C higher than for the same process using NaOH as the delignification agent (see Luo et al., supra).
  • the temperature of delignification with MgO or Mg(OH) 2 must be about 30°C higher than for the same process using NaOH as the delignification agent (see Luo et al., supra).
  • delignification rate can be increased in the O Mg0 process by the addition of a very limited amount of NaOH, since small concentrations of sodium salts can be tolerated in the recovery system of magnesium-based sulphite process.
  • the risk of contamination in the long run is such that this alternative does not represent a desirable selection.
  • pulp such as ozone delignified pulp
  • pulp viscosity For example, it was
  • a single stage bleaching process should be considered, wherein a reducing agent would be added in situ. This would represent a significant advance in pulp bleaching, and bring significant benefits to the industry, because the elimination of one
  • the present invention comprises the conventional steps of oxygen delignification of pulp, namely treating a pulp slurry in a reactor under oxygen overpressure in the presence of an alkali
  • alkali source examples include Ca(OH) 2 , NH 4 OH, NaOH and the like.
  • Reducing agents include sodium
  • the process comprises a first stage
  • the single stage process is much preferred because of the elimination of washing and pressing operations required after treatment with the
  • Figure 1 illustrates the strength properties of O Mg0 + R D 0 E op (DP) bleached pulp
  • the two-stage process is also most advantageous for MgO delignification of
  • the present invention comprises the use of a small amount of a reducing agent
  • Preferred alkaU source are MgO, Mg(OH) 2 and the like.
  • the key feature of the unexpected results obtained with the present single stage process is that the activity of the reducing agent is substantially not affected by the overpressure of oxygen in the reaction media.
  • the reducing agent and the alkaU source may be added
  • the reducing agent is added to the pulp shortly before the alkali source.
  • conditions for carrying the present single stage process are as foUows: pH from 8 to 13; temperature of from 80 to 140 °C; an oxygen overpressure of from 30 to 200 psi; a pulp consistency of from 1% to 50%; an addition of from 0.01% to 10% of sodium borohydride,
  • preferred conditions are: 127 °C; 1 0 psi O 2 pressure; 10% pulp consistency; an addition
  • delignification stage are the same as those above.
  • preferred conditions are as follows: 0.1% to 10% (by weight on pulp) of reducing agent is mixed with a pulp suspension at a pH of from 5 to 13 and maintained at a temperature of 20 to 100°C for a period of time of a few seconds up to 2 hours. The pulp is then washed
  • the pulp are not as good as the single stage treated pulp, or two stage treated pulp wherein
  • the pulp slurry is subsequently transferred to a Parr pressure reactor preheated at a
  • O Mg0 D 0 E op (DP) bleached pulp are inferior to those of the O Mg0 + R D 0 E op (DP) bleached
  • the eastern softwood sulphite pulp (kappa no. 26.0, pulp viscosity 40.1 mPa.s
  • Example 1 determined on the chlorite delignified pulp
  • the reactor preheated at a temperature of about 100°C.
  • the 0 MgO delignification process is performed at a temperature of 127°C with an oxygen overpressure of about 100 psi for 2
  • This example is provided to show the effect of sodium borohydride concentration on the pulp viscosity after the 0 MgO + R deUgnification process.
  • An Eastern softwood sulphite pulp with a kappa no. of 25.2 and viscosity of 43.1 mPa-s determined on the chlorite deUgnified pulp is used.
  • the sodium borohydride concentration varies from 0
  • the required amount of NaBH 4 is rapidly mixed with a pulp slurry having a pulp consistency of 10% and containing about 2% MgO
  • Example 1 The kappa number, viscosity and brightness of the 0 MgO + R delignified pulps
  • Example 4 This example is provided to show that a two-stage RO Mg0 , i.e., treatment with
  • Table 3 shows that the results obtained for a pulp treated under the RO Mg0
  • This example is provided to show that a reduction with sodium borohydride in a second stage after the O ⁇ treatment of the pulp in a first stage, i.e., a O Mg0 R sequence,
  • O Mg ⁇ R treated pulp is substantially lower than that of the single stage O Mg0 + R treated pulp according to the present invention.
  • Example 3 The same Eastern softwood sulphite pulp as in Example 3 is used. 20 g ol pulp is subjected to a first stage O ⁇ process under the conditions of 10% pulp consistency, 2%
  • deUgnification stage For obvious reasons, as mentioned above, a single stage process is most preferred.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
EP98900506A 1997-01-21 1998-01-19 Procede de delignification a l'oxygene de pate a papier Expired - Lifetime EP0960235B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US78621697A 1997-01-21 1997-01-21
US786216 1997-01-21
PCT/CA1998/000020 WO1998031872A1 (fr) 1997-01-21 1998-01-19 Procede de delignification a l'oxygene de pate a papier

Publications (2)

Publication Number Publication Date
EP0960235A1 true EP0960235A1 (fr) 1999-12-01
EP0960235B1 EP0960235B1 (fr) 2002-04-24

Family

ID=25137931

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98900506A Expired - Lifetime EP0960235B1 (fr) 1997-01-21 1998-01-19 Procede de delignification a l'oxygene de pate a papier

Country Status (6)

Country Link
EP (1) EP0960235B1 (fr)
AT (1) ATE216741T1 (fr)
AU (1) AU5546498A (fr)
CA (1) CA2278188C (fr)
DE (1) DE69805056T2 (fr)
WO (1) WO1998031872A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9932709B2 (en) 2013-03-15 2018-04-03 Ecolab Usa Inc. Processes and compositions for brightness improvement in paper production
BR102014027199B1 (pt) * 2014-07-14 2022-10-04 Nalco Company Método para aprimorar a fabricação de polpa de soda ou kraft
US20180030651A1 (en) * 2016-07-27 2018-02-01 Ecolab USA, Inc. Method and compositions for oxygen delignification of chemical pulp

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3809332A1 (de) * 1988-03-19 1989-10-05 Degussa Mehrstufiges verfahren zur bleiche von holzstoffen
FR2692917A1 (fr) * 1992-06-30 1993-12-31 Air Liquide Procédé de blanchiment d'une pâte papetière chimique.
SE502135C2 (sv) * 1994-08-16 1995-08-28 Kvaerner Pulping Tech Bleksekvens för kemisk massa innefattande ett sulfonerande bleksteg
CA2157154A1 (fr) * 1994-08-29 1996-03-01 Gordon Leary Blanchiment a l'oxygene des pates a haut rendement

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9831872A1 *

Also Published As

Publication number Publication date
EP0960235B1 (fr) 2002-04-24
AU5546498A (en) 1998-08-07
DE69805056T2 (de) 2002-11-14
CA2278188A1 (fr) 1998-07-23
WO1998031872A1 (fr) 1998-07-23
CA2278188C (fr) 2003-11-25
ATE216741T1 (de) 2002-05-15
DE69805056D1 (de) 2002-05-29

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