EP0578303B1 - Verfahren zur Delignifizierung von chemischen Zellstoffen - Google Patents

Verfahren zur Delignifizierung von chemischen Zellstoffen Download PDF

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Publication number
EP0578303B1
EP0578303B1 EP93201885A EP93201885A EP0578303B1 EP 0578303 B1 EP0578303 B1 EP 0578303B1 EP 93201885 A EP93201885 A EP 93201885A EP 93201885 A EP93201885 A EP 93201885A EP 0578303 B1 EP0578303 B1 EP 0578303B1
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EP
European Patent Office
Prior art keywords
process according
acid
peroxy acid
organic peroxy
organic
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Revoked
Application number
EP93201885A
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English (en)
French (fr)
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EP0578303A1 (de
Inventor
Patricia B. Walsh
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Solvay Interox Inc
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Solvay Interox Inc
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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
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
    • 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 invention relates to a method for delignifying a chemical paper pulp.
  • the first step of a conventional chemical pulp bleaching sequence aims to complete the delignification of the unbleached pulp as it occurs after the cooking operation.
  • This first delignifying step is traditionally carried out by treating the unbleached pulp with chlorine in an acid medium or by a chlorine-chlorine dioxide association, in mixture or in sequence, so as to cause a reaction with the residual lignin of the pulp and give rise to to chlorolignins which can be extracted from the pulp by dissolving these chlorolignins in an alkaline medium in a subsequent treatment step.
  • Example 5 of document FR-A-1 014 536 an unbleached Kraft paste was treated with a solution of sodium peracetate. According to the description, there was no appreciable chemical degradation of the pulp bleached at a temperature maintained at 30 ° C.
  • the invention aims to remedy the drawbacks of known methods by providing a method which achieves an effective delignification of the unbleached chemical pulp which makes it possible to obtain pulps having high intrinsic qualities over a wide temperature range. It also has the additional advantage of avoiding the use of chlorinated reagents.
  • the invention relates to a process for the delignification of a chemical paper pulp by means of an organic peroxyacid according to which the unbleached pulp from the cooking operation is treated with an aqueous solution of this organic peroxyacid, of which the hydrogen peroxide content does not exceed 20% of the weight of peroxyacid present in the solution.
  • chemical paper pulp the pulp which has already undergone a delignifying treatment in the presence of chemical reagents such as sodium sulfide in alkaline medium (kraft or sulfate cooking), sulfur dioxide or a metallic salt of sulfurous acid in an acid medium (cooking with sulfite or bisulfite).
  • chemical paper pulp the pulps called in the literature "semi-chemical pulps” such as those where the cooking was carried out using a salt of sulfurous acid in neutral medium (cooking with neutral sulfite also called NSSC cooking), as well as pasta obtained by processes using solvents, such as ORGANOSOLV pasta,
  • the invention is particularly intended for pasta which has undergone kraft cooking.
  • All types of wood used for the production of chemical pulp are suitable for carrying out the process of the invention and, in particular those used for kraft pulp, namely softwoods such as, for example, the various species of pine and fir and hardwoods like, for example, beech, oak, eucalyptus and hornbeam.
  • the organic peroxyacid is selected from performic acid and aliphatic carboxylic peroxyacids comprising a single percarboxylic group and a saturated linear or branched alkyl chain of less than 11 carbon atoms.
  • Aliphatic carboxylic peroxyacids with a linear saturated alkyl chain having less than 6 carbon atoms are preferred.
  • Examples of such peroxyacids are peracetic acid, perpropanoic acid, n-perbutanoic acid and n-perpentanoic acid.
  • Peracetic acid is particularly preferred because of its effectiveness and the relative simplicity of its methods of preparation.
  • the organic peroxyacid is selected from diperoxyacarboxylic acids comprising a linear or branched alkyl chain of less than 16 carbon atoms and two substituted percarboxylic groups on carbon atoms located in the alpha-omega 1 position one over the other.
  • Examples of such peroxyacids are 1,6-diperoxyhexanedioic acid, 1,8-diperoxyoctanedioic acid and 1,10-diperoxydecanedioic acid, and 1,12-diperoxydodecanedioic acid.
  • the organic peroxyacid is selected from aromatic peroxyacids comprising at least one percarboxylic group per benzene nucleus.
  • aromatic peroxyacids which have only one group will be chosen percarboxylic by benzene nucleus.
  • An example of such an acid is peroxybenzoic acid.
  • Another variant of the process according to the invention consists in choosing an organic peroxyacid substituted by one or more halogen atoms or by any other organic functional substituent.
  • organic functional substituent is meant a functional group such as the carbonyl group (ketone, aldehyde or carboxylic acid), the alcohol group, the groups containing nitrogen such as the nitrile, nitro, amine and amide groups, sulfur-containing groups such as the sulfo and mercapto groups.
  • the peroxyacid can indifferently be used in the form of an aqueous solution of peroxyacid or alternatively in the form of an ammonium, alkali metal or alkaline earth metal salt of this peroxyacid.
  • the aqueous organic peroxyacid solution has a weight content of hydrogen peroxide which does not exceed 20% of the weight of the peroxyacid.
  • the weight of hydrogen peroxide in the aqueous peroxyacid solution will not exceed 8% of that of the organic peroxyacid and, particularly preferably, will not exceed 6% of this weight.
  • the aqueous organic peroxyacid solution containing only a small amount of hydrogen peroxide in accordance with the invention can be prepared according to any suitable technique aimed at obtaining an aqueous organic peroxyacid solution whose hydrogen peroxide content does not exceed 20% by weight of the peroxyacid.
  • the aqueous solution of peroxyacid is prepared by purification of an aqueous solution of this peracid containing hydrogen peroxide in an amount of more than 20% by weight of the peroxyacid, such as solutions obtained by chemical equilibrium reaction between an aqueous solution of hydrogen peroxide and an aqueous solution of organic acid corresponding to the peroxyacid in the presence of a small amount of a catalyst, for example a strong acid inorganic.
  • a particularly preferred variant consists in carrying out the purification of the peroxyacid solution by distillation.
  • the purified peroxyacid solution obtained is not stored at low temperature, it is recommended to use it without delay according to the process in accordance with the invention, otherwise substantial quantities of hydrogen peroxide will reappear therein. return to the chemical balance of the compounds present in the solution.
  • the treatment according to the invention can be carried out in any type of apparatus suitable for the treatment of paper pulp by means of neutral or acid reagents.
  • the retention tank for unbleached pulp present in all bleaching installations and acting as a buffer tank between the wood cooking unit and the pulp bleaching unit is particularly suitable for carrying out the process according to the invention.
  • the dough can thus be treated there during its storage without requiring the investment of an expensive specific device.
  • the dough can be stored in a pile for an appropriate amount of time: a method known as heap bleaching. This method has the advantage of not requiring a large retention tank for longer reaction times.
  • the treatment with organic peroxyacid is generally carried out at a temperature of at least 25 ° C and preferably at least 50 ° C. Likewise, this temperature does not generally exceed 98 ° C and preferably not 95 ° C. Most often, the treatment is carried out with organic peroxyacid at atmospheric pressure.
  • the duration of this treatment depends on the temperature and the essence of the wood used to prepare the dough, as well as the efficiency of the preceding cooking. Generally times of at least 15 minutes are suitable. Times of at least about 45 minutes are suitable. In most cases, the duration of this treatment does not exceed 360 minutes, but for example in heap bleaching, durations of up to 5 days are also suitable.
  • the consistency of the peroxyacid treatment step organic will generally be chosen equal to or greater than 1% of dry matter and, more often than not, at least 10%. Likewise, the consistency of the treatment step with organic peroxyacid will generally not exceed 40%.
  • the amount of organic peroxyacid used is chosen as a function of the level of residual lignin in the pulp as well as the average duration of the treatment. Generally, amounts of at least 0.5% and preferably at least 1% by weight of peroxyacid relative to the dry paste are suitable. Most often, an amount of peroxyacid will not be used which does not exceed 10% and, preferably, not 5% by weight relative to the dry paste.
  • a decontaminating pretreatment step using an acidic aqueous solution.
  • the purpose of this step is to extract from the pulp the impurities present in the form of metal ions which are detrimental to the proper conduct of the bleaching and / or delignification operations.
  • All the inorganic or organic acids used in aqueous solution, alone or as a mixture are suitable. Strong inorganic acids such as, for example, sulfuric acid or hydrochloric acid are well suited. Sulfuric acid is particularly preferred.
  • the acid decontaminating pretreatment is also carried out in the presence of an agent complexing metal ions.
  • mixtures of the strong inorganic acids mentioned above with organic acids from the class of aminopolycarboxylic or aminopolyphosphonic acids or their alkali metal salts are particularly suitable.
  • suitable aminopolycarboxylic acids are diethylenetriaminepentaacetic acid, ethylenediaminetetraacetic acid, cyclohexanediaminetetraacetic acid and nitrilotriacetic acid.
  • Diethylenetriaminepentaacetic acid (DTPA) is preferred.
  • aminopolyphosphonic acids are diethylenetriaminepenta acid (methylenephosphonic) (DTMPA), ethylenediaminetetra acid (methylenephosphonic), cyclohexanediaminetetra (methylenephosphonic) acid (CDTMPA) and nitrilotri acid (methylenephosphonic). DTMPA is preferred.
  • the amounts of complexing agent to be used depend on the efficiency of the complexing agent selected and on the metal content of the pulp to be treated. In practice, at least 0.01% by weight of complexing agent is generally used relative to the dry paste and, more often than not, at least 0.05%. Likewise, generally not more than 1% by weight of complexing agent relative to the dry paste and, more often than not, 0.25%.
  • the operating conditions for the acid decontaminant pretreatment are not critical. They must be determined in each particular case according to the type of paper pulp and the equipment in which the treatment is carried out. In general, the choice of acid and the quantity used to impose on the medium a pH of less than 7, for example from at least about 1 to at most about 6.5, should be fixed. Especially advantageous pHs are those of at least about 2.0 to at most about 5.0. Temperature and pressure are not critical, with room temperature and atmospheric pressure generally suitable. The duration of the pretreatment can vary within wide limits depending on the type of equipment used, the choice of acid, the temperature and the pressure, for example from about 15 minutes to several hours.
  • the latter are chosen from the same complexing agents as those described above for the decontaminating pretreatment step.
  • An additional possibility is the combination of the decontaminating pretreatment with the incorporation of one or more complexing agents in the delignification step.
  • the effect of delignification with peracetic acid was studied on a hardwood kraft pulp (initial whiteness 28.7 ° ISO, kappa index 16.7 and viscosity 27.4 cps) by means of a sequence in two stages: peracetic acid - extraction with caustic soda.
  • the extraction step with caustic soda was carried out under constant conditions of temperature (77 ° C), duration (45 minutes) and consistency (10% by weight of dry matter).
  • the peracetic acid step was carried out under various temperature conditions ranging from 71 ° C to 93 ° C, the other conditions remaining constant: duration of 180 minutes, amount of peracetic acid of 3% by weight per dry matter ratio and 10% dry matter consistency.
  • the peracetic acid used was an aqueous solution containing 12.4% by weight of peracetic acid, 15.7% of hydrogen peroxide, 29.6% of acetic acid and 0.8% of sulfuric acid.
  • Examples 1R to 3R were repeated, replacing the aqueous solution of peracetic acid with a solution of distilled peracetic acid containing 27.2% by weight of peracetic acid, 1.97% by weight of hydrogen peroxide, 9 , 6% by weight of acetic acid and less than 0.1% by weight of sulfuric acid.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Ultra Sonic Daignosis Equipment (AREA)

Claims (10)

  1. Verfahren zur Delignifizierung eines chemischen Zellstoffs mit Hilfe einer organischen Peroxysäure, gemäß dem man den ungebleichten Zellstoff, der aus dem Kochvorgang hervorgeht, mit einer wäßrigen Lösung dieser organischen Peroxysäure behandelt, dadurch gekennzeichnet, daß die wäßrige Peroxysäurelösung einen auf das Gewicht bezogenen Gehalt an Wasserstoffperoxid besitzt, der 20% des Gewichts der Peroxysäure nicht überschreitet.
  2. Verfahren gemäß Anspruch 1, dadurch gekennzeichnet, daß der auf das Gewicht bezogene Gehalt an Wasserstoffperoxid 8% des Gewichts der Peroxysäure nicht überschreitet.
  3. Verfahren gemäß Anspruch 1 oder 2, dadurch gekennzeichnet, daß die organische Peroxysäure vor ihrer Verwendung durch einen Destillationsvorgang gereinigt wird.
  4. Verfahren gemäß einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die organische Peroxysäure ausgewählt ist unter der Peroxyameisensäure und den aliphatischen Peroxycarbonsäuren, die eine einzige Percarboxylgruppe und eine lineare oder verzweigte gesättigte Alkylkette mit weniger als 11 Kohlenstoffatomen enthalten.
  5. Verfahren gemäß einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die organische Peroxysäure ausgewählt ist unter den Diperoxycarbonsäuren, die eine lineare oder verzweigte Alkylkette mit weniger als 16 Kohlenstoffatomen und zwei Percarboxylgruppen enthalten, die als Substituenten an den relativ zueinander in alpha-omega-Position gelegenen Kohlenstoffatomen sitzen.
  6. Verfahren gemäß einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die organische Peroxysäure ausgewählt ist unter den aromatischen Peroxysäuren, die eine Percarboxylgruppe am Benzolkern enthalten.
  7. Verfahren gemäß einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß man der Behandlung mit der organischen Peroxysäure einen reinigenden Vorbehandlungsschritt mittels einer wäßrigen Säurelösung vorangehen läßt.
  8. Verfahren gemäß Anspruch 7, dadurch gekennzeichnet, daß die wäßrige Säurelösung wenigstens einen Komplexbildner für Metallionen enthält.
  9. Verfahren gemäß einem der Ansprüche 1 bis 8, dadurch gekennzeichnet, daß man bei der Behandlung mit Peroxysäure einen Komplexbildner für Metallionen zufügt.
  10. Anwendung des Verfahrens gemäß einem der Ansprüche 1 bis 9 zur Delignifizierung von Kraftzellstoffen.
EP93201885A 1992-07-06 1993-06-29 Verfahren zur Delignifizierung von chemischen Zellstoffen Revoked EP0578303B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US90808392A 1992-07-06 1992-07-06
US908083 1992-07-06

Publications (2)

Publication Number Publication Date
EP0578303A1 EP0578303A1 (de) 1994-01-12
EP0578303B1 true EP0578303B1 (de) 1996-01-10

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EP93201885A Revoked EP0578303B1 (de) 1992-07-06 1993-06-29 Verfahren zur Delignifizierung von chemischen Zellstoffen

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US (1) US5431781A (de)
EP (1) EP0578303B1 (de)
JP (1) JPH06108392A (de)
AT (1) ATE132926T1 (de)
AU (1) AU666375B2 (de)
BR (1) BR9302768A (de)
CA (1) CA2099828A1 (de)
DE (1) DE69301285T2 (de)
ES (1) ES2086183T3 (de)
FI (1) FI933105A (de)
NZ (1) NZ248082A (de)
SI (1) SI9300364A (de)
SK (1) SK70493A3 (de)

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FI942968A (fi) * 1994-06-20 1995-12-21 Kemira Chemicals Oy Menetelmä kemiallisen massan delignifioimiseksi
FI942970A (fi) * 1994-06-20 1995-12-21 Kemira Chemicals Oy Menetelmä kemiallisen massan delignifioimiseksi
FI98841C (fi) * 1994-06-20 1997-08-25 Kemira Chemicals Oy Menetelmä kemiallisen massan delignifioimiseksi
US6736934B1 (en) * 1995-02-17 2004-05-18 Andritz Oy Method of pretreating pulp in an acid tower prior to bleaching with peroxide
FI104572B (fi) * 1996-05-30 2000-02-29 Kemira Chemicals Oy Menetelmä kemiallisen massan valkaisemiseksi
FR2814180B1 (fr) * 2000-09-18 2003-12-05 Michel Delmas Procede de blanchiment de pates a papier en milieu organique a hydratation controlee
CN101848920A (zh) * 2007-10-17 2010-09-29 新日铁化学株式会社 可溶化木质素、糖类原料和单糖类原料的制法及可溶化木质素
US9551076B2 (en) 2011-05-31 2017-01-24 Clean Chemistry, Inc. Electrochemical reactor and process
US20170107128A1 (en) 2012-09-07 2017-04-20 Clean Chemistry, Inc. System and method for generation of reactive oxygen species and applications thereof
EP3189016B1 (de) 2014-09-04 2020-06-03 Clean Chemistry, Inc. Wasserbehandlungsverfahren unter verwendung einer oxidativen peracetatlösung
CA2981034C (en) 2015-03-26 2024-06-25 Clean Chemistry, Inc. Systems and methods of reducing a bacteria population in high hydrogen sulfide water
CA3007778C (en) 2015-12-07 2023-09-26 Clean Chemistry, Inc. Methods of microbial control
US10883224B2 (en) 2015-12-07 2021-01-05 Clean Chemistry, Inc. Methods of pulp fiber treatment
FI127996B (en) 2016-07-01 2019-07-15 Kemira Oyj Process for treating cellulose
US11136714B2 (en) 2016-07-25 2021-10-05 Clean Chemistry, Inc. Methods of optical brightening agent removal
US11001864B1 (en) 2017-09-07 2021-05-11 Clean Chemistry, Inc. Bacterial control in fermentation systems
US11311012B1 (en) 2017-09-07 2022-04-26 Clean Chemistry, Inc. Bacterial control in fermentation systems

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1014536A (fr) * 1940-04-01 1952-08-18 Du Pont Perfectionnements au blanchiment des pâtes de bois
DE3005947B1 (de) * 1980-02-16 1981-01-29 Degussa Verfahren zur Bleiche von Zellstoffen mittels organischer Persaeure
JPS5721591A (en) * 1980-07-11 1982-02-04 Mitsubishi Gas Chemical Co Peroxide bleaching of wood pulp
US4793898A (en) * 1985-02-22 1988-12-27 Oy Keskuslaboratorio - Centrallaboratorium Ab Process for bleaching organic peroxyacid cooked material with an alkaline solution of hydrogen peroxide
US4826568A (en) * 1985-08-05 1989-05-02 Interox (Societe Anonyme) Process for delignification of cellulosic substances by pretreating with a complexing agent followed by peroxide prior to kraft digestion

Also Published As

Publication number Publication date
JPH06108392A (ja) 1994-04-19
SK70493A3 (en) 1994-02-02
BR9302768A (pt) 1994-02-08
FI933105A (fi) 1994-01-07
DE69301285T2 (de) 1996-08-22
SI9300364A (en) 1994-03-31
ES2086183T3 (es) 1996-06-16
EP0578303A1 (de) 1994-01-12
AU4170493A (en) 1994-01-13
NZ248082A (en) 1995-12-21
DE69301285D1 (de) 1996-02-22
US5431781A (en) 1995-07-11
CA2099828A1 (fr) 1994-01-07
AU666375B2 (en) 1996-02-08
ATE132926T1 (de) 1996-01-15
FI933105A0 (fi) 1993-07-06

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