EP0207062B1 - Chlorierung von Pulpe unter Druck und Einleitung von Chlor in Bläschen - Google Patents

Chlorierung von Pulpe unter Druck und Einleitung von Chlor in Bläschen Download PDF

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Publication number
EP0207062B1
EP0207062B1 EP86890168A EP86890168A EP0207062B1 EP 0207062 B1 EP0207062 B1 EP 0207062B1 EP 86890168 A EP86890168 A EP 86890168A EP 86890168 A EP86890168 A EP 86890168A EP 0207062 B1 EP0207062 B1 EP 0207062B1
Authority
EP
European Patent Office
Prior art keywords
mixer
chlorine gas
slurry
retention vessel
pressure
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.)
Expired
Application number
EP86890168A
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English (en)
French (fr)
Other versions
EP0207062A1 (de
Inventor
Michael I. Sherman
Joseph R. Phillips
Gordon Rowlandson
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.)
Kamyr Inc
Original Assignee
Kamyr Inc
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 Kamyr Inc filed Critical Kamyr Inc
Priority to AT86890168T priority Critical patent/ATE48452T1/de
Publication of EP0207062A1 publication Critical patent/EP0207062A1/de
Application granted granted Critical
Publication of EP0207062B1 publication Critical patent/EP0207062B1/de
Expired legal-status Critical Current

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    • 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
    • D21C9/12—Bleaching ; Apparatus therefor with halogens or halogen-containing compounds

Definitions

  • the invention relates to a method and apparatus for treating a slurry of comminuted fibrous cellulosic material with chlorine gas, the method comprising the steps of (a) intimately mixing chlorine gas with the slurry and (b) subsequently feeding the slurry to a retention vessel.
  • the apparatus comprises a fluidizing mixer for intimately mixing chlorine gas with a slurry, said mixer including at least one chlorine gas introduction nozzle, and a discharge line extending therefrom.
  • chlorine is injected through nozzles into a mixer, and then is passed to a retention vessel which is at approximately atmospheric pressure. During the residence of the pulp in the mixer and the retention vessel the chlorine reacts with impurities and encrustants (such as lignin and bark) in the pulp slurry, to effect desired bleaching or delignification.
  • impurities and encrustants such as lignin and bark
  • the invention as claimed is intended to provide a method and apparatus for treating pulp slurries with chlorine gas, without diluting the chlorine gas prior to its application, for a more efficient treatment and for keeping or maintaining the slurry at a consistency to match or come close to the consistencies in the other stages which may be in the order of up to 16%.
  • steps (a) and (b) of claim 1 are followed by step (c): maintaining the pressure in the retention vessel between about 1 to 10 bar above atmospheric pressure (to enhance the solubility of chlorine gas in the slurry and thereby enhance the solubility of chlorine gas in the slurry and thereby enhance the efficiency and/or efficacy of the chlorine treatment) while continuously feeding the slurry into the retention vessel and continuously discharging the slurry therefrom.
  • the apparatus of the present invention is characterized by a first throttling valve disposed in the discharge line for throttling the slurry discharged from the mixer to thereby control the pressure within the mixer, a retention vessel operatively connected to said discharge line on the opposite side of said first throttling valve from said mixer, said retention vessel including an inlet line connected to the mixer discharge line, and a retention vessel discharge line, and a second throttling valve disposed in the retention vessel discharge line for controlling the pressure within the retention vessel.
  • the elevated pressure within the mixer and/or the retention vessel has the additional effect that thereby the chlorine gas has a tendency to take the form of minute bubbles thus increasing the overall reactivity area, and the network of interlocked fibers at this pressure inhibits the coalescence of gas bubbles.
  • the chlorine gas may be introduced into the mixer through porous material discs, such as porous ceramic discs or porous sintered metal discs having a pore size of about 5-175 ⁇ .Lm, so that from the time of introduction the chlorine is in the form of minute bubbles.
  • porous material discs such as porous ceramic discs or porous sintered metal discs having a pore size of about 5-175 ⁇ .Lm, so that from the time of introduction the chlorine is in the form of minute bubbles.
  • the improvements in solubility of the chlorine gas in the pulp slurry that are achieved according to the present invention result in a number of beneficial effects, including decreased overall chemical consumption, use of more chlorine relative to chlorine dioxide (which is also added during treatment, and which is more costly than chlorine gas), decreased volume of slurry in the retention vessel, treatment to lower Kappa numbers, less chemical wastage, and decreased consumption of bleaching agents in subsequent stages, while the consistency of the pulp slurry which may be in the range of about 2,5-16%, and preferably about 7-12%, is not substantially decreased during treatment.
  • the invention is applicable to a wide variety of procedures for the treatment of comminuted cellulosic fibrous material slurries with chlorine gas.
  • the invention is useful as the first stage of a multistate bleach feed in the bleaching of deciduous wood chemical pulps, coniferous wood chemical pulps, mixtures of chemical pulps, and non-wood fibrous chemical pulps; as the first stage of a delignification procedure as a stage subsequent to an initial delignification using oxygen; and in like bleaching, delignification, and related procedures.
  • Chemical pulp is provided in a conventional bleach feed storage tank 10, the pulp being introduced therein through an inlet 11, and being pumped from the bottom of the tank 10 utilizing a conventional fluidizing centrifugal pump 12, such as the type shown in U.S. Patent 4,435,193.
  • the pulp has a consistency of about 2.5-16%, preferable 3.5-13%, and most preferably about 7-12%.
  • the temperature of the pulp slurry typically will be from 50 ° F-160 ° F (10 to 71 ° C), more preferably 80-150 ° F (27 to 66 ° C).
  • the pulp is pumped in line 13 to conventional fluidizing centrifugal mixer 14.
  • the mixer 14 preferably is capable of fluidizing pulp even if it has a consistency up to about 16%, to effectively intimately mix the pulp with chemicals that are added to it within the mixer.
  • a form such a mixer 16 might take is shown in Canadian Patent 1102604, and such a mixer also is commercially available from Kamyr, Inc. of Glens Falls, New York and sold under the trademark "MC".
  • Chlorine gas from source 15 passes through barometric loop 16' in line 16 and is added to the mixer 14, as is chlorine dioxide from source 17 through line 18.
  • the chlorine gas will have a temperature of about 75 ° F-140 ° F (24 to 60 ° C), and more commonly in the range of about 90 ° F-125 ° F (32 to 52 ° C).
  • the pressure at source 15 and in line 16 typically will be in the range of about 60-125 psig (4,1 to 8,6 bar above atmospheric pressure) conventional safety devices, valves, and interlocks will be used with the chlorine gas system.
  • Chlorine dioxide from source 17 will typically have a temperature of 35 ° F-100 ° F(1,6 to 38 ° C), more commonly 40 ° F-55 ° F (4,4 to 13 ° C).
  • the chlorine dioxide will be added in liquid form, with concentrations ranging from 4-14 gl, preferably 6-10 gl.
  • Total retention time in the pressurized zone is about 0.01-60 minutes, preferably about 0.1-20 minutes.
  • the invention is particularly applicable to the bleaching of deciduous wood chemical pulps with Kappa numbers in the range of 10-25 (more commonly 15-20), bleaching of coniferous wood chemical pulps with Kappa numbers in the range of 25-150 (more commonly 28-38), bleaching of mixtures of chemical pulps, and bleaching of non-wood fibrous chemical pulps with Kappa numbers in the range of 14-150.
  • the pulp is passed to retention vessel 20 and flows upwardly therein with dilution liquid added through introduction structure 21.
  • the pulp is discharged by a scraper into the discharge line 23 at the top of the retention vessel, and then passes into a stock line and from that preferably into a pressure diffuser or like vessel at the same pressure, for further retention or washing under pressure.
  • the solubility of chlorine in the pulp is significantly increased thus causing more efficient reaction with the impurities in encrustants (such as lignin and bark) on, with, and in the pulp fibers.
  • encrustants such as lignin and bark
  • the application of pressure favors the production of minute bubbles of chlorine gas, and the network of interlocked fibers coupled with the increased pressure inhibits the coalescence of gas bubbles.
  • the end result is decreased overall chemical consumption, decreased degree of substitution of chlorine dioxide for chlorine (chlorine dioxide being more expensive), a decreased volume of slurry in the vessel 20, lower extracted Kappa numbers for the pulp, less chemical wastage, and decreased consumption of bleaching agents in subsequent stages.
  • Pressurization of the mixer 14 and vessel 20 is preferably effected utilizing a valve 30 at the discharge from the mixer 14, and a valve 31 at the discharge 23 from the tank 20.
  • the valves 30, 31 may be selected from a wide variety of available throttling valves, such as valves having all wetted parts of materials resistant to the corrosive-aggressive conditions that are present.
  • the valve 30 may comprise a four inch (100 mm) diameter ball valve
  • the valve 31 may comprise an eight inch (200 mm) diameter ball valve.
  • Typical throttling ball valves that can be utilized in this regard are available from WKM of Houston, Texas, and are sold under the tradename DynaSeal 350.
  • valves 30, 31 are operated, either manually or automatically, to control the pressure within the mixer 14 and/or the tank 20 so that it is within the range of about 15-150 psig (1 to 10 bar above atmospheric pressure) (preferably about 30-120 psig) (2 to 8,3 bar above atmospheric pressure).
  • FIGURE 2 shows the chlorine source 15 connected through line 16 to the mixer 14.
  • the particular interconnection structures illustrated in FIGURE 2 include the branched connection 40 which has branch conduits 41,42 extending therefrom.
  • branch conduit In each branch conduit is disposed a filter 44 and one or more valves 45, and each branch conduit terminates in a chlorine gas injecting nozzle 47.
  • Two such structures are utilized in case one malfunctions (in which case it can be closed off and the other utilized until repair is effected), and also to evenly introduce the chlorine gas into the mixer.
  • the injection nozzles 47 (any rea - sonable number of nozzles may be provided) in the embodiment illustrated in FIGURE 2 are connected to the mixer 14 at opposite sides of the circular cross-section pulp inlet portion 50 of the mixer.
  • a typical filter 44 is illustrated in FIGURE 3, and includes the solid annular metal body 52 which mounts a circular disc 53 of porous material.
  • Typical porous material for the disc 53 include porous ceramics and sintered metals.
  • a typical chlorine gas injection nozzle 47 is illustrated in FIGURES 4 and 5 and includes a metal housing including annular flange 55 and annular body 56, with a conical surface 57 formed at the innermost end of the body 56 (the end closest to, or extending into, the mixer 14). Disposed within the body 56 and having a conical surface abutting the conical surface 57 is disc 58.
  • the disc 58 comprises means for introducing the chlorine gas in the form of minute bubbles, and comprises a porous material having pore sizes ranging from about 5-175 um. Typical porous materials utilizable for the formation of the disc 58 are conventionally available porous ceramics and porous sintered metals.
  • the disc 58 is held in place against the conical surface 57 by the gasket 59, locking ring 60, and locking clip 61.
  • the locking ring 60 can be screw- threaded into engagement with the body portion 56 (which has internal threads therein), with the clip 61 engaging the body 56 and the ring 60 to hold them in the position illustrated in FIGURE 4 wherein the ring 60 presses against the gasket 59 and the disc 58.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Apparatus Associated With Microorganisms And Enzymes (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Treating Waste Gases (AREA)
  • Treatment Of Sludge (AREA)
  • Separation Using Semi-Permeable Membranes (AREA)
  • External Artificial Organs (AREA)
  • Materials For Medical Uses (AREA)

Claims (10)

1. Verfahren zum Behandeln eines Breis von gemahlenem faserigen Zellulosematerial mit Chlorgas mit den Schritten (a) inniges Mischen von Chlorgas mit dem Brei und (b) anschließendes Einführen des Breis in einen Retentionsbehälter. (20), umfassend (c) das Aufrechterhalten des Druckes im Retentionsbehälter von etwa 1 bis 10 bar über dem Atmosphärendruck, während der Brei kontinuierlich in den Retentionsbehälter zugeführt und kontinuierlich aus diesem abgeführt wird.
2. Verfahren nach Anspruch 1, wobei der Schritt (a) in einem Mischer (14) ausgeführt wird, gekennzeichnet durch den Schritt der Aufrechterhaltung des Druckes im Mischer von etwa 1 bis 10 bar über dem Atmosphärendruck.
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß der Brei während einer Zeitdauer im Bereich von etwa 0.01 bis 60 min. unter dem Druck von etwa 1 bis 10 bar über dem Atmosphärendruck gehalten wird.
4. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß die Konsistenz des Breis während der Ausführung der Schritte (a) bis (c) im Bereich von etwa 7 bis 12% liegt.
5. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß das Chlor in die Mischung in Form kleinster Bläschen eingeführt wird, um die Löslichkeit im Brei zu verbessern und dadurch die Wirksamkeit der Behandlung zu steigern, indem das Chlorgas durch eine poröse Scheibe (53) mit Porengrößen im Bereich von etwa 5 bis 175 ¡.Lm geleitet wird.
6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß der Brei während der Ausführung der Schritte (a) bis (c) eine Konsistenz von etwa 2,5 bis 16% hat und unter einem Druck von etwa 2 bis 8,3 bar über dem Atmosphärendruck gehalten wird.
7. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß der Druck im Mischer (14) und im Retentionsbehälter (20) durch Steuern des Auslassens von Brei aus dem Mischer (14) mit einem ersten Drosselventil (30) und Steuern des Auslassens von Brei aus dem Retentionsbehälter (20) mit einem zweiten Drosselventil (31) aufrechterhalten wird.
8. Vorrichtung zum Behandeln eines Breis mit Chlorgas, umfassend einen Fluidisierungsmischer (14) zum innigen Mischen von Chlorgas mit einem Brei, wobei der Mischer wenigstens eine Chlorgaseinführdüse (47) und eine von dieser abgehende Auslaßleitung aufweist, und umfassend ein in der Auslaßleitung angeordnetes erstes Drosselventil (30) zum Drosseln des aus dem Mischer (14) abgeführten Breis, um dadurch den Druck im Mischer zu steuern, einen mit der Auslaßleitung an der bezüglich des Mischers anderen Seite des ersten Drosselventils in Wirkverbindung stehenden Retentionsbehälter (20), der eine mit der Auslaßleitung des Mischers verbundene Einlaßleitung und eine Auslaßleitung aufweist, und ein in der Auslaßleitung des Retentionsbehälters angeordnetes zweites Drosselventil (31) zum Steuern des Druckes im Retentionsbehälter.
9. Vorrichtung nach Anspruch 8, dadurch gekennzeichnet, daß die wenigstens eine Chlorgaseinführdüse (47) Mittel zum Einführen von Chlorgas in den Mischer (14) in Form kleinster Bläschen aufweist, umfassend eine in der Düse angeordnete Scheibe (53) aus porösem Material, welche das Chlorgas auf dem Weg in den Mischer durchsetzen muß, wobei das Material Porengrößen im Bereich von etwa 5 bis 175 µm hat.
10. Vorrichtung nach Anspruch 9, dadurch gekennzeichnet, daß die wenigstens eine Chlorgaseinführdüse ein Paar Chlorgaseinführdüsen (47) umfaßt, die annähernd einander gegenüberliegend mit dem Mischer (14) in Wirkverbindung stehen und über Zweigleitungen (41, 42) an eine Chlorgas unter Druck enthaltende gemeinsame Leitung (16) angeschlossen sind, wobei jede der Chlorgaseinführdüsen (47) eine erste Scheibe (58) aus porösem Material enthält und außerdem in jeder der Zweigleitungen eine zweite Scheibe aus porösem Material als Filter (44) zum Ausfiltern von Teilchen aus dem Chlorgasstrom angeordnet ist.
EP86890168A 1985-06-14 1986-06-06 Chlorierung von Pulpe unter Druck und Einleitung von Chlor in Bläschen Expired EP0207062B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86890168T ATE48452T1 (de) 1985-06-14 1986-06-06 Chlorierung von pulpe unter druck und einleitung von chlor in blaeschen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US74467885A 1985-06-14 1985-06-14
US744678 1985-06-14

Publications (2)

Publication Number Publication Date
EP0207062A1 EP0207062A1 (de) 1986-12-30
EP0207062B1 true EP0207062B1 (de) 1989-12-06

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ID=24993592

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86890168A Expired EP0207062B1 (de) 1985-06-14 1986-06-06 Chlorierung von Pulpe unter Druck und Einleitung von Chlor in Bläschen

Country Status (9)

Country Link
EP (1) EP0207062B1 (de)
JP (1) JPS61289192A (de)
AT (1) ATE48452T1 (de)
BR (1) BR8602738A (de)
CA (1) CA1276408C (de)
DE (1) DE3667310D1 (de)
FI (1) FI85728C (de)
NO (1) NO168123C (de)
SE (1) SE466459B (de)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US56833A (en) * 1866-07-31 Improvement in bleaching paper-stock
US1971241A (en) * 1933-04-01 1934-08-21 Pennsylvania Salt Mfg Co Method of chlorination
DE1621684A1 (de) * 1967-10-04 1971-07-08 Bellmer Geb Kg Maschf Maschinenkombination fuer die Leitungsstrecke in Zellstoffaufbereitungsanlagen
SE387671B (sv) * 1973-04-27 1976-09-13 Mo Och Domsjoe Ab Anordning for blekning av kompakt, icke fluffat vetskehaltigt lignocellulosamaterial med gasformiga blekmedel, foretredesvis syrgas

Also Published As

Publication number Publication date
JPS61289192A (ja) 1986-12-19
NO862116L (no) 1986-12-15
EP0207062A1 (de) 1986-12-30
NO168123B (no) 1991-10-07
FI862082A0 (fi) 1986-05-19
FI85728C (fi) 1992-05-25
FI85728B (fi) 1992-02-14
SE466459B (sv) 1992-02-17
NO168123C (no) 1992-01-15
SE8602592L (sv) 1986-12-15
BR8602738A (pt) 1987-02-10
CA1276408C (en) 1990-11-20
FI862082A (fi) 1986-12-15
ATE48452T1 (de) 1989-12-15
SE8602592D0 (sv) 1986-06-10
DE3667310D1 (de) 1990-01-11

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