US3215587A - Continuous process and apparatus for delignification of cellulosic material - Google Patents

Continuous process and apparatus for delignification of cellulosic material Download PDF

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Publication number
US3215587A
US3215587A US252805A US25280563A US3215587A US 3215587 A US3215587 A US 3215587A US 252805 A US252805 A US 252805A US 25280563 A US25280563 A US 25280563A US 3215587 A US3215587 A US 3215587A
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United States
Prior art keywords
zone
moisture
drier
preheater
chips
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Expired - Lifetime
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US252805A
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English (en)
Inventor
Salvatore A Guerricri
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CB&I Technology Inc
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Lummus Co
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Priority to US252805A priority Critical patent/US3215587A/en
Priority to AT15164A priority patent/AT268038B/de
Priority to NO151648A priority patent/NO115163B/no
Application granted granted Critical
Publication of US3215587A publication Critical patent/US3215587A/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • D21C1/00—Pretreatment of the finely-divided materials before digesting
    • D21C1/10—Physical methods for facilitating impregnation

Definitions

  • the present invention relates to continuous vacuum degassing of cellulosic material which has been preheated and dried while maintained in an expanded mass condition.
  • a principal object of the present invention is to provide process and apparatus for achieving a supply of cellulosic matter in substantially uniform condition, a more rapid and uniform liquor impregnation of cellulosic material thereby producing a more uniform pulp upon digestion.
  • Another object of the present invention is to provide a process for substantially eliminating both the air and moisture content of the cellulosic material prior to impregnation.
  • Still another object of the present invention is to provide improved apparatus for substantially eliminating both the air and moisture content of the cellulosic material.
  • the major components of the illustrative apparatus include a preheater wherein the wood chips or like cellulosic material is preheated, a drier wherein the preheated chips are dried, a vacuum tank 30 wherein the dried chips are degassed and subsequently submerged 'in cooking liquor to form a chip-liquor suspension, heat 3,215,587 ?atented Nov. 2, 1965 exchangers 4t) and 50 for raising the suspension to the cooking temperature, and a digester 60.
  • Wood chips or like cellulosic material are introduced into preheater 10 at the open upper end thereof by a conveyor belt or other suitable means, schematically indicated by line 12.
  • Air from line 14 is introduced into the bottom of preheater 10 through spargers or distributors (not shown) and is passed in countercurrent flow to the chips descending through preheater 10.
  • the volume of air being introduced into preheater 10 is sufficient to cause the chips to be maintained as an expanded mass within the preheater 10.
  • the chips are heated by means of steam jackets 16 and 18, which are provided with steam through steam lines 22 and 24, respectively. Condensate is withdrawn from steam jackets 16 and 18 by condensate lines 26 and 28, respectively.
  • the chips are heated to a temperature slightly below the boiling point of Water and some or all of the surface moisture on the chips is removed.
  • the main object of this treatment is to avoid subsequent condensation in the drier 20.
  • the chips in preheater 10 may be alternatively heated by passing air which has been heated to a temperature sufficient to heat the chips to process temperature thereby eliminating the need for providing the preheater 10 with steam jackets 16 and 18.
  • Preheated chips are passed from the bottom of preheater 10 through a rotary valve 32 or other suitable feeding and metering device into the upper portion of drier 20.
  • a steam coil 34 or other suitable heating device is positioned within the drier 20 and is supplied with steam through line 36 for drying the chips.
  • Condensate is withdrawn from coil 34 through line 38.
  • Drier 20 is maintained at a pressure slightly above atmospheric pres- F sure and at a temperature whereby a substantial portion of the moisture in the chips is removed as vapor which is vented from the upper portion of drier 20 through line 42. In the process of vaporizing the water contained in the pores of the chips, a substantial portion of the gases occluded within the pores is also removed from the chips.
  • a portion of the vapor in line 42 is recycled to the bottom of drier 20 through line 44, blower 46 which is driven by motor 48, and line 52.
  • the vapor introduced through line 52 causes the chips to form an expanded mass within drier 20.
  • the chips withdrawn from drier 20 are dry and superheated in respect to the saturation temperature of the water vapor therein, and are fed through a rotary valve 56 or other suitable metering device into vacuum tank 30.
  • Tank 30 is maintained at a subatmospheric pressure from about 1 to 5 p.s.i.a. by a vacuum line 58 in communication with a steam jet evacuator 62 which is supplied with steam through line 64.
  • a mass of chips is formed within tank 30 and the residence time of the chips therein is regulated so that the period of time during which the chips are under vacuum insures that substantially all the remaining air and moisture content of the chips is removed through vacuum line 58 to evacuator 62.
  • Fresh cooking liquor is introduced into tank 30 through line 65 while recycled cooking liquor is introduced through line 66, as more fully hereinafter described.
  • the degassed chips are submerged in the cooking liquor supplied through lines 65 and 66.
  • the liquor level within tank 30 is maintained within the desired range by suitable liquor level controller and associated valves (not shown).
  • a chip-liquor suspension of suitable consistency is withdrawn from tank 30 through line 68 by pump 7% and is passed to a multi-pass countercurrent heat exchanger, generally designated by reference numeral 40, wherein the suspension heated by a hot recycled liquor in a recycle line 72. Impregnation of the chips with cooking liquor primarily takes place in multi-pass heat exchanger 40.
  • the recycled liquor which has been cooled in heat exchanger is withdrawn through line '74 and is passed to heat exchanger 76 for further cooling before introduction into vacuum tank 30 through line 66 to insure that the chips in tank 30 will not be prematurely subjected to cooking temperatures.
  • the chip-liquor suspension is passed through line 78 to heat exchanger 50 wherein the suspension is heated to a temperature within the conventional digest-ion temperature range.
  • the heated suspension is passed through line 80 into the top of digester 60 for digestion while submerged in cooking liquor. Liquor in excess of that required for digestion is removed from digester 60 through line 72 for recycle to tank 30 in the manner hereinbefore set forth.
  • a suitable chip-liquor separator (not shown) may be provided either within digester 60 or exteriorly thereof to facilitate separating excess liquor from the chips and the liquor required in digestion.
  • Digester 60 is provided with a vent line 82 to remove any gas brought in with the chip suspension.
  • the upper portion of digester 60 essentially constitutes a digestion zone While the lower portion constitutes a leaching zone.
  • the chips introduced into the top of digester 60 descend through the cooking zone and upon the completion of digestion pass into the lower leaching zone.
  • Black liquor is removed from digester 60 through line 84 which is provided with a valve 86.
  • Wash liquid is introduced into the leaching zone through line 88 provided with a valve 90.
  • the amount of water introduced is sufficient to cause a portion of the wash liquid to pass upwardly in countercur'rent flow to the digested pulp and thereby leaching out spent liquor which is discharged from digester 60 through line 84.
  • the remaining Wash liquid in addition to leaching liquor from the pulp, dilutes the pulp and the resulting suspension is Withdrawn from the bottom of digester 60 through line 92 provideded with a flow regulating valve 94, or any other suitable metering device, such as a screw press.
  • the pulp may now be further treated in subsequent operations of a conventional nature.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, preheating the material to a temperature slightly below the boiling point of water in a first zone so as to drive off surface moisture from said material, introducing the preheated material into a second heated zone, removing part of the moisture and occluded gases in the pores of the material as overhead vapors, recycling a portion of the overhead vapors to a lower region of the second zone to maintain the material in an expanded mass condition, and vacuum degassing the material in a third zone to remove substantially all moisture and gases from said material.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, preheating material to a temperature slightly below the boiling point of water in a first zone so as to drive off surface moisture from said material, introducing the preheated material into a second heated second zone, removing part of the air and moisture and occluded gases in the pores of the material as overhead vapors, maintaining the material in an expanded mass condition Within the second zone, and vacuum degassing the material in a third zone to substantially all moisture and gases from said material.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, preheating the material to a temperature slightly below the boiling point of Water in a first zone so as to drive oif surface moisture from said material, introducing the preheated material into a second heated zone, removing part of the moisture and occluded gases in the pores of the material as overhead vapors, recycling a portion of the overhead vapors to a lower region of the second zone to maintain the material in an expanded mass condition, vacuum degassing the material in a third zone to remove substantially all moisture and gases from said material, submerging the degassed material in cooking liquor to form a suspension, introducing the suspension into a digester for digestion therein, and recycling liquor from the digester for use in the submerging step.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, preheating the material to a temperature slightly below the boiling point of water in a first zone so as to drive off surface moisture from said mate-rial, introducing the preheated material into a second heated zone, removing part of the moisture and occluded gases in the pores of the material as overhead vapors, recycling a portion of the overhead vapors to a lower region of the second zone to maintain the material in an expanded mass condition, vacuum degassing the material in a third zone to remove substantially all moisture and gases from said material, submerging the degassed material in cooking liquor to form a suspension, heating the suspension to digestion temperature, introducing the heated suspension into a digester for digestion therein, and recycling liquor from thedigester for use in the submerging step.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, pre heating the material to a temperature slightly below the boiling point of water in a first zone so as to drive off surface moisture from said material, introducing the pre heated material into a second heated zone, removing part of the air and moisture in the pores of the material as overhead vapors, maintaining the material in an expanded mass condition within the second zone, vacuum degassing the material in a third zone to remove substantially all the moisture and gases from said material, submerging the degassed material in cooking liquor to form a suspension, introducing the suspension into a digester for digestion therein, and recyling liquor from the digester for use in the submerging step.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, preheating the material to a temperature slightly below the boiling point of Water in a first zone so as to drive off surface moisture from said material, introducing the preheated material into a second heated zone, removing part of the air and moisture in the pores of the material as overhead vapors, maintaining the material in an expanded mass condition within the second zone, vacuum degassing the material in a third zone to remove substantially all moisture and gases from said material, submerging the degassed material in cooking liquor to form a suspension, heating the suspension to digestion temperature, introducing the heated suspension into a digester for digestion therein, and recycling liquor from the digester for use in the submerging step.
  • a process for treating cellulosic material comprising forming an expanded mass of cellulosic material, preheating the material to a temperature slightly below the boiling point of water in a first zone so as to drive off surface moisture from said material, introducing the preheated material into a second zone, removing substantially all of the moisture and air from the pores of said material, recycling a portion of the vapors from said second zone to maintain the material in an expanded mass condition, submerging said material in cooking liquor to form a suspension, heating the suspension to digestion temperatures, introducing the heated suspension into a digester for digestion therein, and recycling liquor from the digester for use in the submerging step.
  • Apparatus for treating cellulosic material comprising a preheater including heating means and gas-feeding means in the lower region of said preheater to maintain the material in an expanded mass condition, a drier receiving preheated material from said preheater and including heating means to drive moisture out of said material as an overhead vapor, means to form the material within said drier into an expanded mass, said last mentioned means including means to recycle a portion of the overhead vapor to a lower region of said drier, a vacuum tank for degassing said material to remove air and moisture from the material, means to feed said material from said drier into said vacuum tank, and means to introduce cooking liquor into said vacuum tank to submerge degassed material in cooking liquor to form a chip-liquor suspension.
  • Apparatus for treating cellulosic material comprising a preheater including heating means and gas-feeding means in the lower region of said preheater to maintain the material in an expanded mass condition, a drier receiving preheated material from said preheater and including heating means to drive moisture out of said material as an overhead vapor, means to form the material Within said drier into an expanded mass, said last mentioned means including means to recycle a portion of the overhead vapor to a lower region of said drier, a vacuum tank for degassing said material to remove air and moisture from the material, and means to introduce said material from said drier into said vacuum tank.
  • Apparatus for treating cellulosic material comprising a drier including heating means to drive moisture out of said material as an overhead vapor, gas-feeding means to form the material Within said drier into an expanded mass, said last mentioned means including means to recycle a portion of the overhead vapor to a lower region of said drier, a vacuum tank for degassing said material to remove air and water vapor from said mate-rial, means to feed said material from said drier into said vacuum tank, means to submerge the degassed material in cooking liquor Within said vacuum tank to form a suspension, a digester, means to supply the suspension to said digester, and means to recycle liquor in excess of that required for digestion to said tank from said digester.
  • Apparatus for pulping cellulosic material comprising a preheater for heating said material to a temperature of about 212 F., gas-feeding means in the lower region of said preheater to maintain the material in said preheater in an expanded mass condition, a drier receiving preheated material from said preheater and including heating means to drive moisture out of said material as an overhead vapor, means to form the material Within said drier into an expanded mass, said last mentioned means including means to recycle a portion of the overhead vapor to a lower region of said drier, a vacuum degasser tank to remove substantially all of the air and moisture content of said material, means to feed said material from said drier into said vacuum tank, means to submerge degassed material in cooking liquor Within said tank to form a suspension, a digester, means to heat the suspension to digestion temperature exteriorly of said digester, means to supply the heated suspension to said digester, and means to recycle liquor in excess of that required for digestion to said tank from said digester.

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US252805A 1963-01-21 1963-01-21 Continuous process and apparatus for delignification of cellulosic material Expired - Lifetime US3215587A (en)

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Application Number Priority Date Filing Date Title
US252805A US3215587A (en) 1963-01-21 1963-01-21 Continuous process and apparatus for delignification of cellulosic material
AT15164A AT268038B (de) 1963-01-21 1964-01-09 Verfahren und Vorrichtung zur Behandlung von Zellulosematerial
NO151648A NO115163B (de) 1963-01-21 1964-01-20

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3347741A (en) * 1964-01-13 1967-10-17 Crane Co Feeder for solid materials
WO1982000838A1 (en) * 1980-08-29 1982-03-18 Chemetics Ab Modo A method for preheating wood chips
AT377023B (de) * 1980-08-29 1985-01-25 Modo Chemetics Ab Verfahren zum vorwaermen von holzschnitzeln
EP0161330A1 (de) * 1984-05-01 1985-11-21 Oliver Armas Laakso Vorbehandlung von Spänen mit Wasserdampf und Luftwäsche
DE3990074T1 (de) * 1988-02-08 1991-01-10 Osmo Aho Verfahren und vorrichtung zur vorbehandlung von zellstoffrohmaterial
FR2650604A1 (fr) * 1988-02-08 1991-02-08 Osmo Aho Procede et equipement pour le pretraitement de matiere cellulosique brute
US5207870A (en) * 1988-02-08 1993-05-04 Osmo Aho Process and equipment for pretreatment of cellulosic raw material
WO1995009267A1 (en) * 1993-09-29 1995-04-06 Antti Aho Pretreatment of chips
US5496439A (en) * 1993-07-28 1996-03-05 Carlson; Willard E. Recycle processing of baled waste material
WO1998035089A1 (en) * 1997-02-07 1998-08-13 Kvaerner Pulping Ab Method and apparatus for preheating an impregnating cellulosic material
US20040244925A1 (en) * 2003-06-03 2004-12-09 David Tarasenko Method for producing pulp and lignin
WO2011154847A3 (en) * 2010-06-08 2012-09-07 Kenneth Hillel Peter Nharris Methods for manufacturing paper fibers and bioethanol from lignocellulosic biomass

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005017952B4 (de) * 2005-04-18 2013-03-07 Voith Patent Gmbh Verfahren zum Entgasen von Streichfarbe

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1413716A (en) * 1922-04-25 A corpora
GB333426A (en) * 1929-09-20 1930-08-14 James Holmes Process of and apparatus for effecting continuous digestion in the extraction of cellulose
US1820994A (en) * 1929-01-31 1931-09-01 Wallin Johan Hugo Process of and apparatus for treating fibrous materials for pulping purposes
US2230119A (en) * 1937-02-18 1941-01-28 Cellulose Res Corp Process of producing wood cellulose
US2640774A (en) * 1953-01-27 1953-06-02 Pulp And Papen Res Inst Of Can Production of cellulose pulp
US2668110A (en) * 1948-06-18 1954-02-02 Spencer Method for fiber liberation in cotton stalks and the pulp
US2675311A (en) * 1948-08-09 1954-04-13 John W Natwick Paper pulp process and apparatus
US2870009A (en) * 1955-06-15 1959-01-20 Kamyr Ab Method and apparatus for the separation of liquids from cellulosic pulp

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1413716A (en) * 1922-04-25 A corpora
US1820994A (en) * 1929-01-31 1931-09-01 Wallin Johan Hugo Process of and apparatus for treating fibrous materials for pulping purposes
GB333426A (en) * 1929-09-20 1930-08-14 James Holmes Process of and apparatus for effecting continuous digestion in the extraction of cellulose
US2230119A (en) * 1937-02-18 1941-01-28 Cellulose Res Corp Process of producing wood cellulose
US2668110A (en) * 1948-06-18 1954-02-02 Spencer Method for fiber liberation in cotton stalks and the pulp
US2675311A (en) * 1948-08-09 1954-04-13 John W Natwick Paper pulp process and apparatus
US2640774A (en) * 1953-01-27 1953-06-02 Pulp And Papen Res Inst Of Can Production of cellulose pulp
US2870009A (en) * 1955-06-15 1959-01-20 Kamyr Ab Method and apparatus for the separation of liquids from cellulosic pulp

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3347741A (en) * 1964-01-13 1967-10-17 Crane Co Feeder for solid materials
WO1982000838A1 (en) * 1980-08-29 1982-03-18 Chemetics Ab Modo A method for preheating wood chips
US4401510A (en) * 1980-08-29 1983-08-30 Modo-Chemetics Ab Process for heating up wood chips prior to steaming and pulping
AT377023B (de) * 1980-08-29 1985-01-25 Modo Chemetics Ab Verfahren zum vorwaermen von holzschnitzeln
EP0161330A1 (de) * 1984-05-01 1985-11-21 Oliver Armas Laakso Vorbehandlung von Spänen mit Wasserdampf und Luftwäsche
US4632729A (en) * 1984-05-01 1986-12-30 Laakso Oliver A Chip presteaming and air washing
US5207870A (en) * 1988-02-08 1993-05-04 Osmo Aho Process and equipment for pretreatment of cellulosic raw material
FR2650604A1 (fr) * 1988-02-08 1991-02-08 Osmo Aho Procede et equipement pour le pretraitement de matiere cellulosique brute
DE3990074T1 (de) * 1988-02-08 1991-01-10 Osmo Aho Verfahren und vorrichtung zur vorbehandlung von zellstoffrohmaterial
DE3990074C2 (de) * 1988-02-08 2000-03-16 Osmo Aho Verfahren zur Vorbehandlung von Zelluloserohmaterial
US5496439A (en) * 1993-07-28 1996-03-05 Carlson; Willard E. Recycle processing of baled waste material
WO1995009267A1 (en) * 1993-09-29 1995-04-06 Antti Aho Pretreatment of chips
WO1998035089A1 (en) * 1997-02-07 1998-08-13 Kvaerner Pulping Ab Method and apparatus for preheating an impregnating cellulosic material
US20040244925A1 (en) * 2003-06-03 2004-12-09 David Tarasenko Method for producing pulp and lignin
US20060169430A1 (en) * 2003-06-03 2006-08-03 Pacific Pulp Resources Inc. Method for producing pulp and lignin
WO2011154847A3 (en) * 2010-06-08 2012-09-07 Kenneth Hillel Peter Nharris Methods for manufacturing paper fibers and bioethanol from lignocellulosic biomass

Also Published As

Publication number Publication date
AT268038B (de) 1969-01-27
NO115163B (de) 1968-08-12

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