SE501325C2 - Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents - Google Patents

Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents

Info

Publication number
SE501325C2
SE501325C2 SE9300277A SE9300277A SE501325C2 SE 501325 C2 SE501325 C2 SE 501325C2 SE 9300277 A SE9300277 A SE 9300277A SE 9300277 A SE9300277 A SE 9300277A SE 501325 C2 SE501325 C2 SE 501325C2
Authority
SE
Sweden
Prior art keywords
pulp
peroxide
acid
acetic acid
bleaching
Prior art date
Application number
SE9300277A
Other languages
Swedish (sv)
Other versions
SE9300277D0 (en
SE501325E (en
SE9300277L (en
Inventor
Erik Nilsson
Petter Tibbling
Original Assignee
Kvaerner Pulping Tech
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 Tech filed Critical Kvaerner Pulping Tech
Priority to SE9300277A priority Critical patent/SE501325E/en
Publication of SE9300277D0 publication Critical patent/SE9300277D0/en
Priority to AU59820/94A priority patent/AU675291B2/en
Priority to CA 2154076 priority patent/CA2154076A1/en
Priority to PCT/SE1994/000054 priority patent/WO1994017239A1/en
Priority to BR9406193A priority patent/BR9406193A/en
Priority to CN 94191058 priority patent/CN1117301A/en
Priority to EP94905899A priority patent/EP0681624A1/en
Priority to JP6516930A priority patent/JPH08505907A/en
Publication of SE9300277L publication Critical patent/SE9300277L/en
Publication of SE501325C2 publication Critical patent/SE501325C2/en
Priority to NO952935A priority patent/NO305763B1/en
Priority to FI953589A priority patent/FI111387B/en
Publication of SE501325E publication Critical patent/SE501325E/en

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
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/166—Bleaching ; Apparatus therefor with per compounds with peracids
    • 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
    • D21C9/1005—Pretreatment of the pulp, e.g. degassing the pulp
    • 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
    • D21C9/1042—Use of chelating agents
    • 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

Abstract

A method of bleaching pulp of cellulosic fibre material without the use of chlorine when manufacturing chemical pulp is described, wherein the pulp entering is fed continuously in a bleaching line and is treated with a sequestering agent in the presence of an acid in order to adjust the pH to a value below 7 and is thereafter bleached in a sequence of several stages consisting of peroxide, at least one organic per-acid and peroxide. According to the invention it is suggested that in the treatment with the sequestering agent the pulp is acidified with acetic acid.

Description

501 325 2 10 15 20 25 30 35 bara viskositets- och styrkeegenskaper och med en mark- nadsmässig ljushet av 87-90% ISO. 501 325 2 10 15 20 25 30 35 viscosity and strength properties and with a market brightness of 87-90% ISO.

Sättet enligt uppfinningen kännetecknas av att vid be- handlingen med komplexbildaren surgöres massan med ättiksyra.The method according to the invention is characterized in that during the treatment with the complexing agent the pulp is acidified with acetic acid.

Den inkommande massan är företrädesvis framställd genom en uppslutningsprocess, som ger lågt kappatal, och där- efter underkastad en delignifiering med syrgas så att massan erhåller ett kappatal av omkring 12 eller därunder och en viskositet av minst omkring 1000 dm3/kg.The incoming pulp is preferably produced by a digestion process, which gives a low kappa number, and then subjected to a delignification with oxygen so that the pulp obtains a kappa number of about 12 or less and a viscosity of at least about 1000 dm3 / kg.

Som peroxid användes företrädesvis väteperoxid.As the peroxide, hydrogen peroxide is preferably used.

Det andra bleksteget, som följer efter det första peroxidsteget, utföres med permyrsyra, perättiksyra eller perpropionsyra, företrädesvis perättiksyra, eller en blandning av minst två av dessa.The second bleaching step, which follows the first peroxide step, is carried out with permyric acid, peracetic acid or perpropionic acid, preferably peracetic acid, or a mixture of at least two of these.

Enligt en lämplig utföringsform tillsättes ättiksyra i en sådan mängd att pH-värdet blir under 6, företrädesvis under 5.According to a suitable embodiment, acetic acid is added in such an amount that the pH value becomes below 6, preferably below 5.

Temperaturen i samtliga bleksteg bör vara 80°C eller där- över, företrädesvis 90°C.The temperature in all bleaching steps should be 80 ° C or above, preferably 90 ° C.

Varje peroxidsteg utföres lämpligen i alkalisk lösning.Each peroxide step is conveniently carried out in alkaline solution.

Persyrasteget utföres företrädesvis i sur lösning. Ättiksyra liksom perättiksyra eller andra lämpliga orga- niska persyror tillverkas företrädesvis on-site.The peracid step is preferably carried out in acidic solution. Acetic acid as well as peracetic acid or other suitable organic peracids are preferably produced on-site.

Massans konsistens under de olika behandlingsstegen är omkring 8-16%, företrädesvis 9-11%. 10 15 s 501 325 Följande exempel belyser uppfinningen ytterligare och visar dess oväntade resultat.The consistency of the pulp during the various treatment steps is about 8-16%, preferably 9-11%. 10 15 p. 501 325 The following examples further illustrate the invention and show its unexpected results.

Exempel Ett flertal försök utfördes på en sulfatmassa av barrved, som delignifierats med syrgas och tvättats. Den deligni- fierade massan hade ett kappatal av 12,1, ljushet 33,7% ISO och en viskositet av 1020 dma/kg. Den inmatades i bleklinjen med en konsistens av 10%, som upprätthölls under behandlingen med komplexbildaren EDTA och under alla blekstegen. I försöken 1 och 2 användes svavelsyra som surgörare i Q-steget, medan ättiksyra användes i för- söken 3 och 4 i enlighet med föreliggande uppfinning. 501 325 10 15 20 25 30 35 4 FQr§Ök 1-4 1. Tillsatser Bleksekvens 2. Betingelser PP P QPPQP 3. Resultat l 2 3 4 Qzâlšg 1. EDTA, kg/BDMT 2,0 2,0 HZSO4, kg/BDMT 6,2 - Ättiksyra, kg/BDMT - 15,0 2. Initial-pH 4,7 4,8 Tid, min 60 60 Temp., °C 70 70 1. H202, kg/BDMT 35 35 MgS04, kg/BDMT 3,0 3,0 NaOH, kg/BDMT 25 25 2. Tid, min 240 240 Temp,°C 90 90 Slut-pH 10,9 11,0 3. Förbr. H2O2, kg/BDMT 18 16 Kappatal 5,1 4,9 Viskositet, dmß/kg 910 911 Ljushet, % ISO 77,3 77,0 Eêzâiâg 1. Perättiksyra, räknat som total H2O2, kg/BDMT 20 30 20 30 2. pH, buffertlösning (natriumacetat) 4,3 4,3 4,3 4,3 Tid, min 240 240 240 240 Temp., °C 90 90 90 90 Forts. 10 15 20 25 30 35 5 501 325 1. Tillsatser Bleksekvens 2. Betingelser QPPaP _QEEaB 3. Resultat 1 2 3 4 3. Förbr. perättiksyra som H2O2, kg/BDMT 11,6 17,9 9,9 14,2 Kappatal 1,1 0,7 1,2 0,9 Viskositet, dmfi/kg 842 814 852 841 Ljushet, % ISO 84,4 87,4 84,4 86,8 1. H2O2, kg/BDMT 4,0 4,0 4,0 4,0 MgSO4, kg/BDMT 3,0 3,0 3,0 3,0 Na0H, kg/BDMT 7,0 7,0 7,0 7,0 2. Tid, min 180 180 180 180 Temp., °C 90 90 90 90 Slut-pH 10,3 10,4 10,6 10,5 3. Förbr. H2O2, kg/BDMT 1,5 1,3 0,9 1,1 Kappatal 0,8 0,5 1,1 0,7 Viskositet, dmß/kg 808 778 834 828 Ljushet, % ISO 88,1 89,3 87,8 89,2 Resultaten visar att de enligt exemplen 3 och 4 förbe- handlade och blekta massorna överraskande har signifikant förbättrade viskositeter, vilket i sin tur indikerar förbättrade styrkeegenskaper, i förhållande till de en- ligt exemplen 1 och 2 förbehandlade och blekta massorna.Examples Several experiments were carried out on a sulphate pulp of softwood, which was delignified with oxygen and washed. The delignified pulp had a kappa number of 12.1, brightness 33.7% ISO and a viscosity of 1020 dma / kg. It was fed into the bleach line with a consistency of 10%, which was maintained during the treatment with the complexing agent EDTA and during all the bleaching steps. In Runs 1 and 2, sulfuric acid was used as the acidifier in the Q step, while acetic acid was used in Runs 3 and 4 in accordance with the present invention. 501 325 10 15 20 25 30 35 4 FQr§Ök 1-4 1. Additives Bleaching sequence 2. Conditions PP P QPPQP 3. Result l 2 3 4 Qzâlšg 1. EDTA, kg / BDMT 2.0 2.0 HZSO4, kg / BDMT 6.2 - Acetic acid, kg / BDMT - 15.0 2. Initial pH 4.7 4.8 Time, min 60 60 Temp., ° C 70 70 1. H 2 O 2, kg / BDMT 35 35 MgSO 4, kg / BDMT 3.0 3.0 NaOH, kg / BDMT 25 25 2. Time, min 240 240 Temp, ° C 90 90 Final pH 10.9 11.0 3. Cons. H2O2, kg / BDMT 18 16 Capacity 5.1 4.9 Viscosity, dmß / kg 910 911 Brightness,% ISO 77.3 77.0 Eêzâiâg 1. Peracetic acid, calculated as total H2O2, kg / BDMT 20 30 20 30 2. pH, buffer solution (sodium acetate) 4.3 4.3 4.3 4.3 Time, min 240 240 240 240 Temp., ° C 90 90 90 90 Cont. 10 15 20 25 30 35 5 501 325 1. Additives Bleaching sequence 2. Conditions QPPaP _QEEaB 3. Results 1 2 3 4 3. Cons. peracetic acid as H2O2, kg / BDMT 11.6 17.9 9.9 14.2 Capacity 1.1 0.7 1.2 0.9 Viscosity, dm fi / kg 842 814 852 841 Brightness,% ISO 84.4 87, 4 84.4 86.8 1. H2O2, kg / BDMT 4.0 4.0 4.0 4.0 MgSO4, kg / BDMT 3.0 3.0 3.0 3.0 NaOH, kg / BDMT 7, 0 7.0 7.0 7.0 2. Time, min 180 180 180 180 Temp., ° C 90 90 90 90 Final pH 10.3 10.4 10.6 10.5 3. Cons. H2O2, kg / BDMT 1.5 1.3 0.9 1.1 Capacity 0.8 0.5 1.1 0.7 Viscosity, dmß / kg 808 778 834 828 Brightness,% ISO 88.1 89.3 87 The results show that the pulps pretreated and bleached according to Examples 3 and 4 surprisingly have significantly improved viscosities, which in turn indicates improved strength properties, compared to the pulps pretreated and bleached according to Examples 1 and 2.

Vid lika satsningar av perättiksyra (Pa) i det andra bleksteget, 20 kg i exemplen 1 och 3 och 30 kg i exemplen 2 och 4, ger ättiksyra i stället för svavelsyra som sur- göringsmedel i Q-steget en viskositetsökning med 26 res- pektive 50 enheter.With equal batches of peracetic acid (Pa) in the second bleaching step, 20 kg in examples 1 and 3 and 30 kg in examples 2 and 4, acetic acid instead of sulfuric acid as acidifier in the Q step gives a viscosity increase of 26 50 units.

Såsom nämnts ovan tillverkas ättiksyra liksom perättik- syra eller andra lämpliga organiska persyror företrädes- vis on-site. Vid framställning av massa kan man således 501 325 ur svartluten utvinna bl.a. ättiksyra i en mängd upp till 50 kg per ton massa. Av den utvunna ättiksyran kan t.ex. perättiksyra framställas pà känt sätt. Sättet enligt upp- finningen kan följaktligen genomföras pá ett ekonomiskt 5 mycket fördelaktigt sätt.As mentioned above, acetic acid as well as peracetic acid or other suitable organic peracids are preferably produced on-site. In the production of pulp, 501,325 can thus be extracted from the black liquor, e.g. acetic acid in an amount up to 50 kg per tonne of pulp. Of the extracted acetic acid, e.g. peracetic acid is prepared in a known manner. The method according to the invention can consequently be carried out in an economically very advantageous manner.

Claims (8)

10 15 20 25 30 35 7 so1 325 P A T E N T K R A V10 15 20 25 30 35 7 so1 325 P A T E N T K R A V 1. Sätt att klorfritt bleka massa av cellulosahaltigt fibermaterial vid framställning av kemisk massa, varvid inkommande massa matas kontinuerligt i en bleklinje och behandlas med en komplexbildare i närvaro av minst en syra för inställning av pH till ett värde under 7 och därefter blekes i en flerstegssekvens bestående av peroxid, en eller flera organiska persyror och peroxid, känne t eckna t av att vid behandlingen med komplex- bildaren surgöres massan med ättiksyra.A method of chlorine-free bleaching pulp of cellulosic fibrous material in the production of chemical pulp, wherein incoming pulp is fed continuously in a bleaching line and treated with a complexing agent in the presence of at least one acid to adjust the pH to a value below 7 and then bleached in a multi-step sequence consisting of peroxide, one or more organic peracids and peroxide, may indicate that during the treatment with the complexing agent, the mass is acidified with acetic acid. 2. Sätt enligt krav l, kännetecknat av att som peroxid användes väteperoxid.Process according to Claim 1, characterized in that hydrogen peroxide is used as the peroxide. 3. Sätt enligt kravleller 2, kännetecknat av att som en eller flera organiska persyror användes per- myrsyra, perättiksyra eller perpropionsyra, företrädesvis perättiksyra eller en blandning av minst två av nämnda persyror .Process according to Claim 2 or 2, characterized in that peramic acid, peracetic acid or perpropionic acid, preferably peracetic acid or a mixture of at least two of said peracids is used as one or more organic peracids. 4. Sätt enligt något av kraven 1-3, k än ne t eckn a t av att ättiksyran, tillsättes i en sådan mängd att pH- -värdet blir under 6, företrädesvis under 5.4. A method according to any one of claims 1-3, characterized in that the acetic acid is added in such an amount that the pH value becomes below 6, preferably below 5. 5. Sätt enligt något av kraven l-4, k ä n n e t e c k n a t av att varje peroxidsteg utföres i alkalisk lösning.5. A method according to any one of claims 1-4, characterized in that each peroxide step is carried out in alkaline solution. 6. Sätt enligt något av kraven l-S, kännetecknat av att massans konsistens under nämnda behandling med komplexbildare och nämnda bleksekvens är omkring 6-l6%, företrädesvis 9 - 1 1% .A method according to any one of claims 1 to 5, characterized in that the consistency of the pulp during said treatment with complexing agents and said bleaching sequence is about 6-166%, preferably 9-1 1%. 7. Sätt enligt något av kraven l-6, kännetecknat av att den inkommande massan har behandlats med syrgas och uppvisar ett kappatal av omkring 14 eller därunder, 501 325 10 15 20 25 30 35 företrädesvis 12 eller därunder och mest föredraget 10 eller därunder.A method according to any one of claims 1-6, characterized in that the incoming mass has been treated with oxygen and has a kappa number of about 14 or less, preferably 12 or less and most preferably 10 or less. 8. Användning av ättiksyra som surgöringsmedel vid be- handling av en kemisk massa med en komplexbildare vid klorfri blekning av massa, varvid inkommande massa matas kontinuerligt i en bleklinje och behandlas med komplex- bildaren i närvaro av ättiksyran för inställning av pH till ett värde under 7, och därefter blekes i en fler- stegssekvens bestående av peroxid, en eller flera orga- niska persyror och peroxid.Use of acetic acid as an acidifying agent in the treatment of a chemical pulp with a complexing agent in chlorine-free bleaching of pulp, the incoming pulp being fed continuously in a bleaching line and treated with the complexing agent in the presence of the acetic acid to adjust the pH to a value below 7, and then bleached in a multi-step sequence consisting of peroxide, one or more organic peracids and peroxide.
SE9300277A 1993-01-29 1993-01-29 Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents SE501325E (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
SE9300277A SE501325E (en) 1993-01-29 1993-01-29 Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents
JP6516930A JPH08505907A (en) 1993-01-29 1994-01-26 Chlorine-free bleaching method for pulp using acetic acid as acidifying agent
BR9406193A BR9406193A (en) 1993-01-29 1994-01-26 Process for bleaching pulp of cellulosic fiber material without the use of chlorine
CA 2154076 CA2154076A1 (en) 1993-01-29 1994-01-26 Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent
PCT/SE1994/000054 WO1994017239A1 (en) 1993-01-29 1994-01-26 Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent
AU59820/94A AU675291B2 (en) 1993-01-29 1994-01-26 Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent
CN 94191058 CN1117301A (en) 1993-01-29 1994-01-26 Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent
EP94905899A EP0681624A1 (en) 1993-01-29 1994-01-26 Method for chlorine-free bleaching of pulp with acetic acid as acidifying agent
NO952935A NO305763B1 (en) 1993-01-29 1995-07-24 Process of chlorine-free bleaching of pulp using acetic acid as an acidifying agent
FI953589A FI111387B (en) 1993-01-29 1995-07-27 Method for chlorine-free bleaching of pulp with acetic acid as an acidifying agent

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE9300277A SE501325E (en) 1993-01-29 1993-01-29 Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents

Publications (4)

Publication Number Publication Date
SE9300277D0 SE9300277D0 (en) 1993-01-29
SE9300277L SE9300277L (en) 1994-07-30
SE501325C2 true SE501325C2 (en) 1995-01-16
SE501325E SE501325E (en) 1999-06-09

Family

ID=20388704

Family Applications (1)

Application Number Title Priority Date Filing Date
SE9300277A SE501325E (en) 1993-01-29 1993-01-29 Process for chlorine-free bleaching of pulp, wherein the pulp is acidified with acetic acid in the treatment with complexing agents

Country Status (10)

Country Link
EP (1) EP0681624A1 (en)
JP (1) JPH08505907A (en)
CN (1) CN1117301A (en)
AU (1) AU675291B2 (en)
BR (1) BR9406193A (en)
CA (1) CA2154076A1 (en)
FI (1) FI111387B (en)
NO (1) NO305763B1 (en)
SE (1) SE501325E (en)
WO (1) WO1994017239A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1050642C (en) * 1996-06-25 2000-03-22 华南理工大学 Everyday production 30-150 ton high concentration paper pulp bleaching method by using hydrogen peroxide
CN103726382B (en) * 2013-12-31 2016-08-17 安徽泾县千年古宣宣纸有限公司 A kind of pure straw Chinese art paper and chloride-free bleaching production process thereof
EP3882380B1 (en) * 2020-03-16 2022-04-27 Re:NewCell AB One stage method for acid metal removal and bleach

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2219505C3 (en) * 1972-04-21 1974-10-17 Deutsche Gold- Und Silber-Scheideanstalt Vormals Roessler, 6000 Frankfurt Chlorine-free multi-stage bleaching of cellulose
DE2841013C2 (en) * 1978-09-21 1984-06-07 Degussa Ag, 6000 Frankfurt Process for full bleaching of pulp
ATE97179T1 (en) * 1989-06-06 1993-11-15 Eka Nobel Ab PROCESS FOR BLEACHING LIGNOCELLULOSE CONTAINING PULP.
SE468355B (en) * 1991-04-30 1992-12-21 Eka Nobel Ab CHEMISTRY OF CHEMICAL MASS THROUGH TREATMENT WITH COMPLEX PICTURES AND OZONE

Also Published As

Publication number Publication date
SE9300277D0 (en) 1993-01-29
SE501325E (en) 1999-06-09
CA2154076A1 (en) 1994-08-04
NO952935D0 (en) 1995-07-24
JPH08505907A (en) 1996-06-25
FI953589A0 (en) 1995-07-27
WO1994017239A1 (en) 1994-08-04
FI111387B (en) 2003-07-15
AU675291B2 (en) 1997-01-30
NO305763B1 (en) 1999-07-19
AU5982094A (en) 1994-08-15
CN1117301A (en) 1996-02-21
NO952935L (en) 1995-09-13
FI953589A (en) 1995-07-27
EP0681624A1 (en) 1995-11-15
SE9300277L (en) 1994-07-30
BR9406193A (en) 1996-01-09

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