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WO1998013547A1 - Cuisson de pate chimique dans une liqueur exempte de soufre contenant un compose accelerant la delignification - Google Patents

Cuisson de pate chimique dans une liqueur exempte de soufre contenant un compose accelerant la delignification Download PDF

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Publication number
WO1998013547A1
WO1998013547A1 PCT/SE1997/001610 SE9701610W WO9813547A1 WO 1998013547 A1 WO1998013547 A1 WO 1998013547A1 SE 9701610 W SE9701610 W SE 9701610W WO 9813547 A1 WO9813547 A1 WO 9813547A1
Authority
WO
WIPO (PCT)
Prior art keywords
cooking
process according
stage
pulp
delignification
Prior art date
Application number
PCT/SE1997/001610
Other languages
English (en)
Inventor
Sören GUSTAVSSON
Christer Fahlgren
Bo Boder
Ewa Westlund-Johansson
Original Assignee
Kvaerner Pulping 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 Kvaerner Pulping Ab filed Critical Kvaerner Pulping Ab
Priority to AT97943269T priority Critical patent/ATE241033T1/de
Priority to DE69722226T priority patent/DE69722226D1/de
Priority to EP97943269A priority patent/EP0928349B1/fr
Publication of WO1998013547A1 publication Critical patent/WO1998013547A1/fr

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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/22—Other features of pulping processes
    • D21C3/222—Use of compounds accelerating the pulping 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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes

Definitions

  • the present invention relates to a process for producing chemical pulp from comminuted cellulose- containing material without using sulphur-containing cooking liquids.
  • the process according to the invention includes at least one impregnation stage followed by at least one cooking stage, with a deligniflcation- acceleratmg compound, such as an anthraqumone, being supplied to at least one of the said stages.
  • a first cooking liquid which has been extracted from a position downstream of the impregnation stage is supplied to the impregnation stage, with the said first cooking liquid primarily containing OH " ions as the active substance.
  • a metal-complexing agent is supplied to the impregnation stage or to another stage located upstream of the cooking stage.
  • the process according to the invention is suitable for producing chemical pulp from essentially all the generally available raw materials for cellulose production.
  • suitable raw materials are softwood chips derived from fir and pine and hardwood chips derived from birch, aspen and eucalyptus.
  • the process according to the invention is also suitable for producing pulp from non-Scandinavian raw materials such as southern pine or loblolly pine and can also be used for producing pulp from straw, reed-grass, esparto grass and other alternative raw materials.
  • the process according to the invention is suitable both for producing pulp which i s intended for ECF or TCF bleaching and for producing unbleached high- yield pulp.
  • a familiar problem associated with producing pulp by the sulphate method or the sulphite method is the problem of troublesome smells in the vicinity of the pulp mill and, in certain cases, even at a distance of several tens of kilometres.
  • These smell problems are principally caused by various sulphur compounds which are produced when pulp is cooked using sulphur- containing cooking liquids. Examples of such malodorous compounds are hydrogen sulphide (HS) and methyl- mercaptan (CH,SH) .
  • HS hydrogen sulphide
  • CH,SH methyl- mercaptan
  • Various solutions, such as pur:fy ⁇ ng exhaust gases and improving the sealing of the pulp manufacturing process, have been proposed for remedying the smell problems.
  • a disadvantage of using sulphur-containing cooking liquids for cooking pulp is that a relatively complicated chemical recovery system is required in order to be able to recirculate the chemicals.
  • the presence of sulphur also impedes efforts, which have been in progress for a long time now, to close the pulp manufacturing process.
  • patent specification SE-C2-502 667 previously disclosed a method for producing chemical pulp from comminuted cellulose-containing material, which method comprised cooking the fibre material with a cooking liquid.
  • the object of the invention which is described is stated as being that of producing a chemical pulp which, after the cooking, already has a substantially reduced content of transition metals and at the same time has considerably improved properties, especially, but not exclusively, with regard to tear resistance, viscosity, yield, kappa number and brightness.
  • the method which is described for producing chemical pulp is stated to be suitable for any method for producing chemical pulp, including anthraquinone/hydroxide pulp (NaOH/KOH) as well. No cooking liquids containing sulphur are used in a pulp manufacturing process of this nature.
  • An object of the present invention is therefore to provide a process for producing chemical pulp from comminuted cellulose-containing material, which process yields a perfectly satisfactory pulp quality at a competitive cost without any sulphur-containing cooking liquid having to be used.
  • This object of the invention is achieved by the process according to the invention including at least one impregnation stage followed by at least one cooking stage with at least one concurrent cooking zone and at least one countercurrent cooking zone and, as the conclusion to the cooking stage, at least one extended displacement zone, with a delignification-acceleratmg compound being supplied to at least one of the said stages and a first cooking liquid, which has been drawn off from a position downstream of the impregnation stage, being supplied to the impregnation stage, with the cooking liquid essentially containing OH " ions as the active substance, and by the concentration of OH " ions in the said concurrent cooking zone being higher than m the said impregnation stage, preferably at least 20" higher and most preferably at least 50 higher.
  • the concentration of OH " ions at the beginning of the concurrent cooking zone of the cooking stage must exceed 0.5 mol/1, and preferably 0.7 mol/1. Most preferably, the concentration of OH ions must exceed 1.0 mol/1.
  • a delignification- acceleratmg compound for example anthraqumone, is supplied when the process according to the invention is being implemented.
  • the total delignification- acceleratmg compound added should exceed 1 kg per tonne of bone dry wood and preferably exceed 1.5 kg per tonne of bone dry wood.
  • the optimum amount to be added is between 1.8 and 2.5 kg per tonne of bone dry wood.
  • the quantity of delignification-acceleratmg compound which is added to the impregnation stage mutt be less than 50 ( ⁇ by weight of the total amount added and preferably less than 30. by weight. The best results are obtained if less than 10, by weight of the total amount of the delignification-acceleratmg compound added is added to the impregnation stage. It has also been found that the total quantity of delignification-acceleratmg compound which is added must exceed 0.5o by weight of the total quantity of effective alkali (EA) , calculated as NaOH, which is added to the process.
  • EA effective alkali
  • the total quantity of delignification-accelerating compound should exceed 1" by weight, and most preferably be from 1.1 to 1.5" by weight, of the total quantity of effective alkali (EA) which is added.
  • EA effective alkali
  • this provides a more efficient delignification process, thereby making it possible to achieve a second mam object of the invention, namely that of providing a process for producing chemical pulp, which process requires a lower temperature during cooking than do previously known processes for producing pulp without sulphur-containing cooking liquids, for example soda-anthraqumone cooking accordance with the state of the art.
  • the lower temperature level which can be used in the process according to the invention results in lower energy consumption and in there being less risk of carbohydrate breakdown.
  • the temperature in the impregnation stage when implementing the invention, may be within the interval 80-140°C, it should preferably be between 100 and 130°C, and should most preferably be between 120 and 127°C.
  • the subsequent cooking stage may, when cooking softwood, be within the interval 150-170°C, it should preferably be between 158 and 163°C.
  • the temperature m the said cooking stage may be within the interval 140-165°C and should preferably be between 155 and 158°C.
  • a metal-complexmg agent is supplied to the impregnation stage or to another stage upstream of the cooking stage.
  • a metal-complexmg agent is understood as being a compound which has the ability to bind metals which are harmful to the pulp production process m the form of metal complexes which can, if required, be removed from the process.
  • metal complex-containing extraction liquid which has been extracted from the impregnation stage can be removed from the process or conveyed to evaporation.
  • an excess of cooking liquid which has been extracted from the cooking stage can be conveyed to evaporation at the same time.
  • DTPA diethyl- t ⁇ ammepentaacetic acid
  • EDTA ethylenediamine- tetraacetic acid
  • a second cooking liquid having a lower concentration of OH " ions than is present in the said first cooking liquid, is supplied to the previously mentioned extended displacement zone.
  • the kappa number after the cooking stage is between 15 and 30, and preferably between 18 and 25, when softwood pulp which is intended for bleaching is being cooked.
  • the kappa number is between 9 and 25, and preferably between 12 and 18, when hardwood pulp which is intended for bleaching is being cooked.
  • the kappa number is between 40 a d 100, and preferably between 50 and 85, when high-yield pulp which is not to be bleached is being cooked.
  • a bleaching sequence is advantageously used which comprises the bleaching stages (Q) (OP) (ZQ) (PO) .
  • the process according to the invention can be implemented using apparatus and equipment which are suitable for preparing pulp and which are familiar to the skilled person.
  • FIG. 1 shows the tensile index as a function of the number of revolutions when beating m a PFI beater
  • Fig. 2 shows the tear index as a function of the number of revolutions when beating m a PFI beater
  • Fig. 3 shows the tear index as a function of the tensile index
  • Fig. 4 shows the tensile index as a function of the density
  • Fig. 5 shows the tensile index as a function of the number of revolutions when beating in a PFI beater
  • Fig. 6 shows the tear index as a function of the number of revolutions when beating in a PFI beater
  • Fig. 7 shows the tear index as a function of the tensile index
  • Fig. 8 shows the tensile index as a function of the density.
  • the invention is illustrated using process data and results from a number of laboratory experiments.
  • the experiments are reported in Tables 1 to 7 below.
  • the tables record cooking experiments using processes according to the invention and experiments using conventional isothermal (ITC) sulphate cooking together with experiments using isothermal (ITC) soda-anthraquinone cooking in accordance with the state of the art.
  • results are recorded from a number of oxygen- delignification and bleaching experiments.
  • Impregnation liquid was allowed to circulate through the digester at 125°C for 45 minutes at the same time as a nitrogen pressure of 10 bar was applied.
  • the nitrogen pressure was released from the digester and the temperature was raised to the cooking temperature at the same time as further cooking liquid was added.
  • the dwell time during this phase was 60 minutes .
  • the fully cooked chips were transferred to a propeller-equipped disintegrator for defibenng for a period of 15 minutes.
  • the pulp was screened in two stages, with the coarser rejects being separated off in a perforated screen basket having a hole diameter of 1. mm under a water pressure of 150 kPa .
  • the remaining fine rejects were separated off on a vibrating diaphragm screen having a 0.15 mm gap-width.
  • the said Table 1 also records the corresponding process parameters and results for a cooking experiment which was carried out using isothermal (ITC) soda- anthraqumone cooking in accordance with tne state of the art, see experiment No. ITC 1618.
  • ITC isothermal
  • Enclosed Table 2 records process parameters from two oxygen-delignification experiments, m this case for pulp which was cooked by conventional ITC sulphate cooking and for pulp which was cooked by a process according to the invention.
  • the other pulps were oxygen-delignified in a similar manner, after which the pulps were bleached.
  • Table 3 records process parameters and results from ECF bleaching experiments using the bleaching sequence (DQ) (PO) .
  • ECF stands for elemental chlorine-free and may, like the abbreviations used in the bleaching sequence, be regarded as being familiar to skilled persons in the field.
  • Table 3 pulp which was cooked by conventional ITC sulphate cooking, or pulp which was cooked by isothermal soda- anthraquinone cooking in accordance with the state of the art, was bleached after oxygen-delignification .
  • Table 4 likewise records corresponding process parameters and results from an ECF bleaching experiment using the bleaching sequence (DQ) (PO) , but in this case for an oxygen-delignified pulp which was cooked by a process according to the invention.
  • Table 5 likewise records results from bleaching experiments with an oxygen-delignified pulp which was cooked m accordance with the invention; however, m this case, a TCF bleaching sequence, i.e. Q(OP) (ZQ) (PO) , was used.
  • TCF stands for totally chlorine-free, which, like the bleaching sequence, is probably familiar to skilled persons in the field.
  • Table 6 records the pulp properties of the unbleached pulps which were obtained by means of the cooking experiments recorded in Table 1.
  • Table 7 records the pulp properties of pulp which was cooked by a process according to the invention and which, after oxygen-delignification, was bleached by means of ECF bleaching, using the bleaching sequence (DQ) (PO) , or by means of TCt bleaching using the bleaching sequence Q(OP) (ZQ) (PO) .
  • Unbleached softwood pulp which has been produced by the process according to the invention exhibits, at the same kappa number, yields and tear resistances which are of the same level as those for a sulphate pulp produced by conventional ITC sulphate cooking.
  • Pulp which has been produced m accordance with the invention exhibits a tear resistance which is clearly higher than that of pulp which has been produced by isothermal (ITC) soda-anthraqu one cooking m accordance with the state of the art.
  • ITC isothermal
  • Q(0P) (ZQ) (PO) bleaching sequence (TCF bleaching) likewise shows that, in this case too, a perfectly satisfactory brightness can be achieved for pulp which has been produced in accordance with the invention.
  • the results obtained show that the process m accordance with the invention makes it possible to produce both unbleached and bleached pulps having perfectly satisfactory pulp properties without any use of sulphur-containing cooking liquids and at a substantially lower cooking temperature than in the case of isothermal soda-anthraqumone cooking m accordance with the state of the art.
  • Weighted mean fibre length mm 2.16 2.22

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Paper (AREA)
  • Micro-Organisms Or Cultivation Processes Thereof (AREA)

Abstract

Cette invention se rapporte à un procédé pour produire une pâte chimique à partir de matériaux contenant de la cellulose broyés sans utiliser de liquide de cuisson contenant du soufre, ce qui élimine les problèmes, par exemple les problèmes de mauvaises odeurs, qui sont associées aux liquides contenant du soufre. Ce procédé utilise au moins une phase d'imprégnation suivie par au moins une phase de cuisson, un composé accélérant la délignification étant utilisé au moins dans l'une de ces phases. Dans ce procédé, un premier liquide de cuisson, qui a été extrait d'une position en aval de la phase d'imprégnation et qui contient essentiellement des ions OH- comme substance active, est utilisé dans la phase d'imprégnation. Il est ainsi possible d'obtenir une concentration d'ions OH- plus grande que dans le cas d'une cuisson à la soude et à l'anthraquinone traditionnelle et d'utiliser une température de traitement plus basse. Ce procédé est approprié pour la production de pâte chimique essentiellement à partir de tous les matériaux bruts généralement disponibles pour la production de cellulose et également pour la production de pâte chimique à partir de matériaux bruts non scandinaves ainsi que pour la production de pâte chimique à partir d'autres matériaux bruts fibreux. Ce procédé est approprié à la fois pour la production de pâte chimique qui est destinée à un blanchiment exempt de chlore à l'état atomique ou à un blanchiment entièrement exempt de chlore et pour la production de pâte à rendement élevé non blanchie.
PCT/SE1997/001610 1996-09-26 1997-09-25 Cuisson de pate chimique dans une liqueur exempte de soufre contenant un compose accelerant la delignification WO1998013547A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AT97943269T ATE241033T1 (de) 1996-09-26 1997-09-25 Schwefelfreies verfahren zur herstellung eines chemischen zellstoffs
DE69722226T DE69722226D1 (de) 1996-09-26 1997-09-25 Schwefelfreies verfahren zur herstellung eines chemischen zellstoffs
EP97943269A EP0928349B1 (fr) 1996-09-26 1997-09-25 Procede exempt de soufre pour la production d'une pate chimique

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE9603518-3 1996-09-26
SE9603518A SE510775C2 (sv) 1996-09-26 1996-09-26 Svavelfri kokning av kemisk massa

Publications (1)

Publication Number Publication Date
WO1998013547A1 true WO1998013547A1 (fr) 1998-04-02

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1997/001610 WO1998013547A1 (fr) 1996-09-26 1997-09-25 Cuisson de pate chimique dans une liqueur exempte de soufre contenant un compose accelerant la delignification

Country Status (5)

Country Link
EP (1) EP0928349B1 (fr)
AT (1) ATE241033T1 (fr)
DE (1) DE69722226D1 (fr)
SE (1) SE510775C2 (fr)
WO (1) WO1998013547A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6241851B1 (en) 1998-03-03 2001-06-05 Andritz-Ahlstrom Inc. Treatment of cellulose material with additives while producing cellulose pulp
US6569289B2 (en) 1999-09-13 2003-05-27 Andritz Inc. Cellulose slurry treating systems for adding AQ to a cellulose slurry in the substantial absence of alkali
CN105200838A (zh) * 2015-09-18 2015-12-30 新疆国力源投资有限公司 一种制备竹柳漂白浆的方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AU3537578A (en) * 1977-05-02 1979-10-25 Australian Paper Manufacturers Limited Alkaline pulping process
US4181565A (en) * 1976-12-10 1980-01-01 Honshu Seishi Kabushiki Kaisha Process for cooking lignocellulosic material in the presence of hydroxyanthracenes and derivatives thereof
EP0010451A1 (fr) * 1978-10-25 1980-04-30 C.I.L. Inc. Procédé de délignification d'une matière lignocellulosique et produits obtenus
WO1995002726A1 (fr) * 1993-07-12 1995-01-26 Kvaerner Pulping Technologies Ab Production de pate de cellulose

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4181565A (en) * 1976-12-10 1980-01-01 Honshu Seishi Kabushiki Kaisha Process for cooking lignocellulosic material in the presence of hydroxyanthracenes and derivatives thereof
AU3537578A (en) * 1977-05-02 1979-10-25 Australian Paper Manufacturers Limited Alkaline pulping process
EP0010451A1 (fr) * 1978-10-25 1980-04-30 C.I.L. Inc. Procédé de délignification d'une matière lignocellulosique et produits obtenus
WO1995002726A1 (fr) * 1993-07-12 1995-01-26 Kvaerner Pulping Technologies Ab Production de pate de cellulose

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6241851B1 (en) 1998-03-03 2001-06-05 Andritz-Ahlstrom Inc. Treatment of cellulose material with additives while producing cellulose pulp
US6569289B2 (en) 1999-09-13 2003-05-27 Andritz Inc. Cellulose slurry treating systems for adding AQ to a cellulose slurry in the substantial absence of alkali
US6576084B1 (en) 1999-09-13 2003-06-10 Andritz Inc. Method of pretreating pulp with yield or strength-enhancing additive
CN105200838A (zh) * 2015-09-18 2015-12-30 新疆国力源投资有限公司 一种制备竹柳漂白浆的方法

Also Published As

Publication number Publication date
SE9603518L (sv) 1998-03-27
EP0928349B1 (fr) 2003-05-21
SE510775C2 (sv) 1999-06-21
DE69722226D1 (de) 2003-06-26
ATE241033T1 (de) 2003-06-15
SE9603518D0 (sv) 1996-09-26
EP0928349A1 (fr) 1999-07-14

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