US1989571A - Method of and apparatus for bleaching and refining pulp - Google Patents

Method of and apparatus for bleaching and refining pulp Download PDF

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Publication number
US1989571A
US1989571A US609732A US60973232A US1989571A US 1989571 A US1989571 A US 1989571A US 609732 A US609732 A US 609732A US 60973232 A US60973232 A US 60973232A US 1989571 A US1989571 A US 1989571A
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United States
Prior art keywords
pulp
bleaching
tower
chamber
zone
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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 - Lifetime
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US609732A
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English (en)
Inventor
Thorne Carl Busch
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Individual
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Individual
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Publication date
Application filed by Individual filed Critical Individual
Priority to US609732A priority Critical patent/US1989571A/en
Priority to DET41021D priority patent/DE602156C/de
Priority to GB19412/32A priority patent/GB393106A/en
Priority to FR739910D priority patent/FR739910A/fr
Priority to US671800A priority patent/US1970148A/en
Priority to GB14800/33A priority patent/GB415224A/en
Priority to BE396596D priority patent/BE396596A/xx
Priority to FR756626D priority patent/FR756626A/fr
Application granted granted Critical
Publication of US1989571A publication Critical patent/US1989571A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/18—Pulping cellulose-containing materials with halogens or halogen-generating compounds
    • 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
    • D21C3/24—Continuous 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
    • 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

Definitions

  • the invention has for object to provide an improved method of increased efliciency, economy, and safety, and is particularly, though not exclusively, applicable to the treatment of wood pulp.
  • a considerable saving'of bleaching medium is effected, and the process is continuous and easily controlled. It enables a gaseous bleaching medium to be. used with complete safety; the apparatus requires much less space than ordinary low density bleaching apparatus, the time required'for bleaching is greatly reduced,,and an improved product is produced.
  • a further object of the invention is to provide in a process of this character an absorption zone, in which the preliminary absorption period may be varied at will, and provide for the initial penetration of the pulp by the bleaching medium.
  • Another object is to provide for maximum efficiency in the step of the processinvolvingthe treatment 'of low density pul
  • a still further object of the inventicn is to provide for the utilization of-all the-gases of the bleaching medium, avoiding their escape into the the same time utilizing them to treat the white waterso that it may be reused in the process. 1
  • the accompanyi g drawing is a vertical sectional elevation and illustrates diagrammatically, and by way of example, one form of apparatus for carrying the invention into effect, the iull line arrows indicating the directionof flow of the pulp and the dotted arrows the gases.
  • the low density pulp to be bleached enters the apparatus through the pipe 2 and flows together with a measure quantity of chlorine gas or chlorine water into a mixer 3 where the pulp and bleaching medium are thoroughly mixed, 4 represents a tower provided with an upper chamber 5 and lower chamber 5'.
  • An agitator 6 rotates in the chamber 5 to assist in keeping the fibres in suspension in the liquid;
  • a scraper arm '1 is located at thebottom or the tower 4 and rotatesat a very slow speed to assist in the removal of the pulp from the tower.
  • the sraper arm '1 is driven by any suitable means, such as a shaft 8, which is connected to the speed-reducer 9.
  • the pulp which is red to the mixer 3 is at low density, for example, between 3% and 6%.
  • the pulp which is red to the mixer 3 is at low density, for example, between 3% and 6%.
  • it leaves the mixer 3 it flows down a channel 10 intothebottomoithehamherSinwhichit 32, Serial No. 609,732
  • Means are preferably provided for controlling the level to-which the pulp can rise, and thus the time that the pulp will remain, in the chamber 5. As illustrated, these means comprise a vertically adjustable gate valve or'weir 12, controlled, for example, from above by means of a hand wheel 13. The pulp then gradually flows downward in the chamber 5' and flows out through a chute 14 to a tank 15.
  • a valve 16 is placed in the chute 14 and this valve is automatically controlled by a float 1'1 which is connected to the valve 16 by a weighted arm 18 and a cable 19 guided by pulleys 20. It will be seen that as the level of the pulp in the chamber 5' drops, the float 1'1 will also drop and thus wholly or partially close the valve 16 and retard the flow of the pulp through the chute 14 and so cause the pulp to rise-again in the tower to the desired level.
  • a pipe 21 is provided through which caustic or any other chemical may be added if desired.
  • the pulp from the tank passes through a pump 22, through a pipe 23 up to a washer and thickener 24 where it is washed and concentrated to a high density of say, 15% or more. From the-thickener the pulp drops down a chute into a mixer 25. Bleach medium from the tank 26 is also fed to the mixer 25 and the pulp and bleaching medium are very intimately mixed before dropping into a high density tower 2'1.
  • This high density tower may conveniently be of the kind described in applicants United States Patent No. 1,642,978, dated September 20, 1927. 1
  • pulp gradually descends in the tower 2'1 tothe bottom opening thereof.
  • a scraper arm 28 scrapes the pulp towards the centre opening so that the pulp is discharged uniformly from across the whole diameter of the tower.
  • pulp is preferably diluted by water from a pipe 29 and is washed out through a spout 30 into a tank 31 from which the pulp is delivered by a pump 32 to a washer 33, and thence to any known system of low densitybleaching indicated diagrammatically at 34.
  • the above describes a threestage system of bleaching in which the first stage is at low density and the bleaching medium is either chlorine gas or chlorine water.
  • the sec- The The third stage is the customary low density system using a hypochlorous or similar bleaching medium.
  • the chemical treatment which takes a bleaching medium in a continuous system of bleaching has been the difiiculty ofv confining the gas and therefore making it safe to operate.
  • the chamber 5 forms a perfect seal for the gas andthat the system is entirely closed so that there can be no danger from escaping gases.
  • Some gas will, of course, be ,given oil in both the towers 4 and 27 and pipes and 36 are provided to convey these gases to a recovery system.
  • recovery tower is filled above its perforated false bottom 39 with a filling such as acid resistant glazed tile.
  • a spray 40 which sprays water on to the tile.
  • the gases rise in the tower 38 and are absorbed by the water which is trickling down over the tile.
  • the resultant hypochlorous solution flows through a pipe seal 41 'into a box 42 from where it is returned to the spray 40 through a pump 43.
  • the hypochlorous solution has reached the desired concentration, it is bled through a pipe 44 and is led to any desired point ofconsumption, for instance, to the bleach liquor box 26.
  • the white water thus treated is rendered fit for reuse in the mill process due to chlorine gas combining with the slimy ingredients in the white water.
  • chamber 5 and its associated parts need not necessarily be placed in the tower 4, but may be constructed as a separate unit located at any convenient point,
  • the steps in the process can be varied if desired in order to suit the particular conditions required by" certain classes ofpulps.
  • the high density stage may be used'first followed by the low density using chlorine gas or chlorine water and then bleaching medium is fed into the lower end of a closed absorption zone, maintaining the mixture in said zone for a predetermined period of time to permit absorption by the pulp of the bleaching medium, gently agitating the mixture substantially only adjacent the bottom of said zone to. avoid segregation of fibre and to maintain the upper portion of said mixture in a substantially unagitated state, and in the second stage'discharging the mixture into a reaction zone, maintaining the mixture therein in a quiescent state for a predetermined period of time and then dischargng the same from said reaction zone.
  • a continuous two-stage method of bleaching low density pulp which comprises feeding a mixture of said pulp and a bleaching agent into the lower end of an absorption zone, closed to the atmosphere, so as to avoid agitation of the upper portionof the mass in said zone, maintaining the bulk of said mass in a substantially unagitated' absorption zone and wherein the period of absorption is varied by changing the depth of said absorption zone.
  • Apparatus for bleaching pulp comprising, in combination a mixer for pulp and bleaching agent, a chamber providing a substantially quiescent absorption zone and a second chamber providing a quiescent reaction zone, both said zones being closed to the atmosphere, a conduit for feeding a mixture of pulp and bleaching agent from said mixer to the bottom of said absorption zone, a variable reaction weir, adjacent the top of said discharge zone, for feeding said mixture directly to the upper portion of the reaction zone, a discharge outlet in the bottom of said reaction zone and means in each-of said zones, operative adjacent their bottoms only, for preventing undue segregation or. accumulation of fibre at the bottoms of said chambers.
  • Apparatus for bleaching pulp comprising a mixer for pulp. and bleaching agent, a bleaching chamber including an absorption zone inits upper end and a reaction zone in its lower end, a conduit leading from said mixer into near the bottom of said absorption zone, said mixer discharging through said conduit into the bottom of said absorption zone which is provided with an outlet at its top, a second conduit connecting said outlet with the upper part of said reaction zone and adapted for discharging into the top of said reaction zone and means for preventing accumulation of fibre in the bottom of each of said zones.

Landscapes

  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US609732A 1932-05-03 1932-05-06 Method of and apparatus for bleaching and refining pulp Expired - Lifetime US1989571A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US609732A US1989571A (en) 1932-05-03 1932-05-06 Method of and apparatus for bleaching and refining pulp
DET41021D DE602156C (de) 1932-05-03 1932-07-07 Verfahren zum fortlaufenden Bleichen von Zellstoff
GB19412/32A GB393106A (en) 1932-05-03 1932-07-08 Method of and apparatus for bleaching pulp
FR739910D FR739910A (fr) 1932-05-03 1932-07-12 Procédé de blanchiment de la cellulose
US671800A US1970148A (en) 1932-05-03 1933-05-19 Process for the continuous treatment of vegetables with soda and gaseous chlorine for the industrial production of cellulose
GB14800/33A GB415224A (en) 1932-05-03 1933-05-22 Improvements in process for the continuous treatment of vegetable materials with soda and gaseous chlorine for the industrial production of cellulose
BE396596D BE396596A (enrdf_load_stackoverflow) 1932-05-03 1933-05-30
FR756626D FR756626A (fr) 1932-05-03 1933-06-07 Perfectionnements au procédé de traitement continu des végétaux par la soude et le chlore gazeux pour la fabrication industrielle de la cellulose

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
CA393106X 1932-05-03
US609732A US1989571A (en) 1932-05-03 1932-05-06 Method of and apparatus for bleaching and refining pulp
IT415224X 1932-06-10

Publications (1)

Publication Number Publication Date
US1989571A true US1989571A (en) 1935-01-29

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Family Applications (2)

Application Number Title Priority Date Filing Date
US609732A Expired - Lifetime US1989571A (en) 1932-05-03 1932-05-06 Method of and apparatus for bleaching and refining pulp
US671800A Expired - Lifetime US1970148A (en) 1932-05-03 1933-05-19 Process for the continuous treatment of vegetables with soda and gaseous chlorine for the industrial production of cellulose

Family Applications After (1)

Application Number Title Priority Date Filing Date
US671800A Expired - Lifetime US1970148A (en) 1932-05-03 1933-05-19 Process for the continuous treatment of vegetables with soda and gaseous chlorine for the industrial production of cellulose

Country Status (5)

Country Link
US (2) US1989571A (enrdf_load_stackoverflow)
BE (1) BE396596A (enrdf_load_stackoverflow)
DE (1) DE602156C (enrdf_load_stackoverflow)
FR (2) FR739910A (enrdf_load_stackoverflow)
GB (2) GB393106A (enrdf_load_stackoverflow)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL128867C (enrdf_load_stackoverflow) * 1942-09-09
DE868434C (de) * 1949-08-07 1953-02-26 Henkel & Cie Gmbh Verfahren zur Herstellung von celluloseglycolsauren Salzen
NL93061C (enrdf_load_stackoverflow) * 1950-05-11
US2730426A (en) * 1951-06-20 1956-01-10 Cellulose Dev Corp Ltd Treating vegetable fibrous material with chlorine gas
DE971953C (de) * 1951-11-13 1959-04-23 A Hering Ag Verfahren und Einrichtung zum Aufschliessen von Pflanzenfaserstoffen
US2731208A (en) * 1952-01-28 1956-01-17 Hospital Sanitation Equipment Apparatus for disposing of contaminated waste
AT387995B (de) * 1987-06-12 1989-04-10 Andritz Ag Maschf Austragvorrichtung
AT394738B (de) * 1990-09-03 1992-06-10 Andritz Ag Maschf Verfahren und vorrichtung zum austragen eines mediums aus einem behaelter

Also Published As

Publication number Publication date
BE396596A (enrdf_load_stackoverflow) 1933-06-30
FR739910A (fr) 1933-01-19
GB393106A (en) 1933-06-01
US1970148A (en) 1934-08-14
FR756626A (fr) 1933-12-13
GB415224A (en) 1934-08-23
DE602156C (de) 1934-09-04

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