US3802956A - Method for impregnation of cellulosic fiber material with digesting liquor while preventing dilution of said liquor - Google Patents

Method for impregnation of cellulosic fiber material with digesting liquor while preventing dilution of said liquor Download PDF

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Publication number
US3802956A
US3802956A US00124857A US12485771A US3802956A US 3802956 A US3802956 A US 3802956A US 00124857 A US00124857 A US 00124857A US 12485771 A US12485771 A US 12485771A US 3802956 A US3802956 A US 3802956A
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United States
Prior art keywords
liquor
vessel
impregnation
fiber material
digesting
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Expired - Lifetime
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US00124857A
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English (en)
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E Backlund
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Metso Fiber Karlstad AB
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Kamyr AB
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Publication of US3802956A publication Critical patent/US3802956A/en
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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

Definitions

  • the object of the invention is to raise the concentration of the digesting liquor 'with which the fibre material is impregnated in said vessel, in order to shorten the time required for the subsequent digestion and to obtain a more uniform pulp quality and other advantages.
  • the digesting liquor is diluted with the moisture present in the untreated chips and, as the impregnation step usually is preceded by steaming of the chips, also with condensed steam. Therefore, thechips can hardly absorb a sufficient quantity of liquor to impregnate them with the total amount of active chemicals required for the subsequent digestion, but an additional amount of active chemicals must be supplied during the digestion period by diffusion into the fibre material from liquor surrounding the chips in the digester. 1
  • the fibre material before thestart of the digestion period shall have absorbed the amount of active chemicals required for the lignin dissolution, it has already been proposed to use digesting liquor with an extremely high concentration.
  • the white liquor usually does not contain more than 130-150 grams per litre of active alkali, NaOl-l of wood chips (but also may consist of straw, bagasse, reed or other cellulosic plant materials) is supplied from a chips bin 11 through rotary low-pressure valve 13 to the steaming vessel A.
  • Steam of low pressure e.g., 1 atmosphere overpressure, is supplied to said vessel through a conduit 15, and air is driven off through the conduit 17.
  • the chips pass through the steaming vessel in about 2-5 minutes and then drop down into a rotary high-pressure valve 19 of the kind wherein a rotor having pockets or diametrical passages turns in a stationary casing. From said valve the chips are pumped to the top of the impregnation vessel B by means of circulating liquid which is forced by the pump 20 to flow through the conduits 21, 23. The liquid flushes chips out of the valve 19 and the suspension of chips is driventhrough the conduit 21 to the space inside a strainer girdle 25 inserted in the top of the impregnationvessel, from where the chips are passed on downwardly by a feeding screw '27. Liquid.
  • the liquid to wood ratio during the digestion is lowered by withdrawing liquid in steam form from the vessel in which the fibre material is impregnated with digesting liquor.
  • Said method also requires theuse of special equipment for the evaporation of the digesting liquor and is comparatively difficult to control.
  • the present invention relates to a new and simpler method of concentrating the digesting liquor in connection with the impregnation of chips therewith.
  • digesting liquor is supplied to and spread over a zone of the impregnation vessel situated distantly from the bottom as well as from the top of said vessel, said liquor being driven partly upwards in counter-current to the fibre.
  • the shown plant comprises'three treatment vessels,
  • the fibre material which usually consists is a device for the continuous discharge of chips which have been impregnated with digesting liquor during their continuous movement downwardly through the vessel.
  • Said device comprises a disc or table 45 sup ported by a rotary vertical shaft 43.
  • Said table extends over the greater part of the cross-section of the impregnation vessel and is formed with one or more radially extending slots through which the chips can pass to the lower side thereof.
  • the table is made in accordance with the US. Pat. No. 2,960,'l6l.
  • the chips suspension is transferred to the top of the digester C by means of liquid (digesting liquor) circulating in the conduits 53, 55.
  • the conduit 53 is connected directly to an outlet 57 at the bottom of the impregnation vessel.
  • a pump 59 is inserted in the return conduit connected to the nozzles 49. The pump 59 maintains such a heavyflow in the conduits 53, 55 and in the space 47 that chips entering said space are brought along and flushed out through the outlet 57.
  • the table 45 serves as a screen that retains the chips column so that the same doesnot block the outlet, and consequently the chips will be diluted and suspended merely in the immediate vicinity of the outlet 57.
  • conduits 53, 55 are connected to a separation device 52.
  • the supply conduit 53 opens out inside a'cylindrical strainer 54in the separation dethrottling device 101.
  • the return conduit 55 is connected to the space outside 'of said strainer.
  • the chips retained by the strainer and drained of free liquor. are fed by a motordriven conveyer screw 56 up through the obliquely slanting casing of the separation device and are deliv- 5 ered at its'upper end into the top of the digester C.
  • digested fibre material is discharged at the lower end of the digester by means of a rotary scraper 99 and a
  • the application of the present invention to the above described plant requires a modified design of the im- ,pregnation vessel B.
  • the main feature of said rnodifica tion is the provision of a strainer girdle 28 for separation of liquid from the chips column.
  • Said strainer girdle is inserted in the wall of the upper part of the impre'gna'tion vessel at a distance from the top of the vessel preferablylying between a fifth and a third of the possible alkali content thereof is utilized.
  • Said liquid consists of chips moisture, condensed steam and black liquor.
  • black liquor is supplied through the conduit 33 and serves as a conveying medium for flushing chips out of the valve 19 for their transfer to the top of the impregnation vessel.
  • Said displaced liquid which contains very little of active digesting chemicals, is separated from the chips by the strainer 28 and departs through the conduit 30, the pores and 'interspaces of the chips instead being filled up with white liquor.
  • the concentration of active alkali gets considerably higher than if the white liquor were simply mixed into the fibre suspension, i.e., without any orderly flow relatively thereto and without the withdrawal of a fraction having a low alkali content.
  • the chips will retain in their pores a quantity of alkali sufficient for the subsequent digestion which therefore can be performed in steam phase.
  • the liquid level in the digester total quantity of supplied liquid can be placed immediately above the strainer girdle 87.
  • a certain amount of free liquor can be allowed to flow over from the separating device 52 to the digester and the liquid level may be placed so high (e.g., at the level shown by the drawing) that the digestion takes place wholly or partly in liquid phase.
  • an advantage is gained consisting in that the lignin dissolution takes place with a comparatively great liquor concentration which involves a shortened digestion'time period.
  • the amount of liquid withdrawn through the strainer 28 is determined by the liquid to wood ratio desired during the digestion and by the total liquid flow to the impregnation vessel.
  • the liquid balance of the impregnation vessel may e.g. be the following:
  • the liquid quantity withdrawn by the strainer 28 does not contain any significant quantity of effective alkali. In the practice, this has proved possible to realize, so that the withdrawn liquid merely contains chips moisture, steam condensate, black liquor, and a small amount of white liquor out of which the chips have absorbed substantially all effective alkali.
  • the above described embodiment may be modified as to its details, particularly in respect of the location and the arrangement of the withdrawal strainer 28 and the liquor supply.
  • the withdrawal may take place at the top of the impregnation vessel, e.g., by connecting the conduit 30 to the space outside of the top strainer 25. Then the strainer 28 is no longer required.
  • a method for digestion of cellulosic fiber material by impregnation of the fiber material with digesting liquor in an impregnation vessel and continuous transfer of the impregnated fiber material from the bottom of the impregnation vessel to the top of a digester comprising the steps of: supplying and spreading digesting liquor over a zone of the impregnation vessel, the zone being located distant from the bottom and top of the impregnation vessel, driving the digesting liquor from said zone, partly upwards co'untercurrent to the fiber material while displacing the impregnating liquid introduced into the impregnation vessel together with the fiber material, and partly downwards co-current through the fiber material towards the bottom of the impregnation vessel, straining off the liquid displaced upwardly by the digesting liquor from the fiber material at a point which, measured in the vertical direction, is situated between the top of the impregnation vessel and the zone where the digesting liquor is supplied to the impregnation vessel and discharging the separated displaced liquid from the impregn
  • Method according to claim 1 comprising the further steps of supplying digesting liquor centrally in the impregnation vessel and spreading radially in all direction and distributing over the cross-section of the fiber material column, draining off a corresponding amount of liquor at the periphery of said column and recirculating said liquor.
  • Method according to claim 1 comprising the further steps of introducing digesting liquor into the impregnation vessel also at the top thereof, together with the fiber material, and straining off and discharging a corresponding liquid quantity containing wholly or partly spent digesting chemicals together with the liq- I uid displaced by the digesting liquor supplied farther down in the vessel.
  • Method according to claim 1 comprising the fur- I ther step of: combining liquid withdrawn from the fiber material in the impregnation vessel with spent liquor obtained by the digestion, for common recovery of chemicals therein.

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  • Paper (AREA)
US00124857A 1970-03-17 1971-03-16 Method for impregnation of cellulosic fiber material with digesting liquor while preventing dilution of said liquor Expired - Lifetime US3802956A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE03501/70A SE359331B (de) 1970-03-17 1970-03-17

Publications (1)

Publication Number Publication Date
US3802956A true US3802956A (en) 1974-04-09

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Application Number Title Priority Date Filing Date
US00124857A Expired - Lifetime US3802956A (en) 1970-03-17 1971-03-16 Method for impregnation of cellulosic fiber material with digesting liquor while preventing dilution of said liquor

Country Status (8)

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US (1) US3802956A (de)
JP (1) JPS5324521B1 (de)
CA (1) CA936309A (de)
DE (1) DE2112633C3 (de)
FI (1) FI54155C (de)
FR (1) FR2084755A5 (de)
NO (1) NO129361B (de)
SE (1) SE359331B (de)

Cited By (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3941650A (en) * 1974-08-09 1976-03-02 Schnyder Auxilius P Continuous digester
US4071399A (en) * 1976-09-01 1978-01-31 Kamyr, Inc. Apparatus and method for the displacement impregnation of cellulosic chips material
US4104113A (en) * 1976-06-21 1978-08-01 Kamyr, Inc. Two-stage digestion with between vessel heating
US4155805A (en) * 1978-01-19 1979-05-22 Kamyr Aktiebolag Method for continuously digesting cellulosic fiber by evenly spreading the fiber material over the digestion vessel with steam
US4162933A (en) * 1973-05-15 1979-07-31 Kamyr Inc. Exothermic heat as a means of determining the degree of delignification
US4190490A (en) * 1974-04-03 1980-02-26 Domtar Inc. Impregnation and digestion of wood chips
US4432836A (en) * 1979-07-30 1984-02-21 Kamyr, Inc. Vessel false bottoming
US4438970A (en) * 1980-10-09 1984-03-27 Paccar Inc. Vehicle cab suspension
US4514910A (en) * 1983-02-22 1985-05-07 Kamyr, Inc. Dehydration of lignite or the like
US4536969A (en) * 1983-09-30 1985-08-27 Kamyr, Inc. Hot water drying of low rank coal
US4746400A (en) * 1979-07-30 1988-05-24 Kamyr, Inc. Method of treating cellulosic chips in a vessel with a false bottom
DE3938504A1 (de) * 1988-12-20 1990-06-21 Kamyr Ab Verfahren zum kontinuierlichen aufschliessen von zellulosefasermaterial
US5053108A (en) * 1989-06-28 1991-10-01 Kamyr Ab High sulfidity cook for paper pulp using black liquor sulfonization of steamed chips
EP0477059A2 (de) * 1990-09-20 1992-03-25 Kvaerner Pulping Technologies AB Tränkung mit Schwarzlauge vor der Zufuhr der Weisslauge
WO1993004232A1 (en) * 1991-08-23 1993-03-04 Kamyr Aktiebolag A process for the continuous digestion of cellulosic fiber material
US5192396A (en) * 1988-12-20 1993-03-09 Kamyr Ab Process for the continuous digestion of cellulosic fiber material
AU639109B2 (en) * 1990-08-17 1993-07-15 Kamyr Inc. Sulfite modified continuous digesting
US5236553A (en) * 1989-06-28 1993-08-17 Kamyr Ab Continuous cooking with reduced horsepower and pulp degradation
US5529661A (en) * 1991-08-23 1996-06-25 Kvaerner Pulping Technologies Ab Process for controlling the flow of cellulosic fiber material through an impregnation vessel
US5536366A (en) * 1993-05-04 1996-07-16 Ahlstrom Machinery Inc. Digester system for implementing low dissolved solids profiling
WO1997003244A1 (en) * 1995-07-12 1997-01-30 Kvaerner Pulping Ab Impregnation of fiber material
WO1997003243A1 (en) * 1995-07-12 1997-01-30 Kvaerner Pulping Ab Impregnation of fibre material
US5674359A (en) * 1995-02-08 1997-10-07 Ahlstrom Machinery Inc. Continuous cooking of cellulosic fibrous material with cold alkali impregnation
US5766413A (en) * 1993-04-23 1998-06-16 Kvaerner Pulping Ab Process for isothermal cooking pulp in a continuous digester
US5795438A (en) * 1996-11-04 1998-08-18 Ahlstrom Machinery Inc. Method and apparatus for feeding multiple digesters
US5882477A (en) * 1997-02-10 1999-03-16 Ahlstrom Machinery, Inc. Continuous digester with a low temperature gas-phase
US5985096A (en) * 1997-09-23 1999-11-16 Ahlstrom Machinery Inc. Vertical pulping digester having substantially constant diameter
US6120647A (en) * 1998-01-26 2000-09-19 Ahlstrom Machinery Inc. Simplified liquid removal system for a cellulose pulp digester
US6123808A (en) * 1997-12-09 2000-09-26 Ahlstrom Machinery Inc. Distribution of dilution liquor to the discharge of a cellulose pulp digester
US6248208B1 (en) 1995-06-02 2001-06-19 Andritz-Ahlstrom Inc. Pretreatment of chips before cooking
US6468390B1 (en) * 1998-08-24 2002-10-22 Kvaerner Pulping Ab Method for continuous cooking of lignocellulosic fiber material
WO2005064078A1 (en) 2003-12-30 2005-07-14 Kvaerner Pulping Ab Feed of a mixture of chips and fluid from a low-pressure system to a high-pressure system
WO2006037860A1 (en) * 2004-10-04 2006-04-13 Metso Paper, Inc. Improved alkaline process and system for producing pulp
WO2009082338A1 (en) 2007-12-20 2009-07-02 Metso Fiber Karlstad Ab Method for kraft pulp production where hemicelluloses are returned
US10625190B2 (en) * 2014-06-26 2020-04-21 Valmet Ab Steam separation unit for a system for hydrolysis of lignocellulosic biomass material

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE7604167L (sv) * 1976-04-08 1977-10-09 Reinhall Rolf Bertil Anordning for behandling av lignocellulosahaltigt material i ett undertryck staende reaktionskerl
DE2927579C2 (de) * 1979-07-07 1981-08-27 J.M. Voith Gmbh, 7920 Heidenheim Verfahren und Vorrichtung zum drucklosen Imprägnieren von Fasermaterial für die Zellstoffherstellung
FI71176C (fi) * 1983-11-30 1991-12-03 Ekono Oy Foerfarande foer framstaellning av cellulosa med satsvis kokning.

Cited By (47)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4162933A (en) * 1973-05-15 1979-07-31 Kamyr Inc. Exothermic heat as a means of determining the degree of delignification
US4190490A (en) * 1974-04-03 1980-02-26 Domtar Inc. Impregnation and digestion of wood chips
US3941650A (en) * 1974-08-09 1976-03-02 Schnyder Auxilius P Continuous digester
US4104113A (en) * 1976-06-21 1978-08-01 Kamyr, Inc. Two-stage digestion with between vessel heating
US4071399A (en) * 1976-09-01 1978-01-31 Kamyr, Inc. Apparatus and method for the displacement impregnation of cellulosic chips material
US4155805A (en) * 1978-01-19 1979-05-22 Kamyr Aktiebolag Method for continuously digesting cellulosic fiber by evenly spreading the fiber material over the digestion vessel with steam
US4746400A (en) * 1979-07-30 1988-05-24 Kamyr, Inc. Method of treating cellulosic chips in a vessel with a false bottom
US4432836A (en) * 1979-07-30 1984-02-21 Kamyr, Inc. Vessel false bottoming
US4438970A (en) * 1980-10-09 1984-03-27 Paccar Inc. Vehicle cab suspension
US4514910A (en) * 1983-02-22 1985-05-07 Kamyr, Inc. Dehydration of lignite or the like
US4536969A (en) * 1983-09-30 1985-08-27 Kamyr, Inc. Hot water drying of low rank coal
DE3938504A1 (de) * 1988-12-20 1990-06-21 Kamyr Ab Verfahren zum kontinuierlichen aufschliessen von zellulosefasermaterial
US5080755A (en) * 1988-12-20 1992-01-14 Kamyr Ab Process for the continuous digestion of cellulosic fiber material
US5192396A (en) * 1988-12-20 1993-03-09 Kamyr Ab Process for the continuous digestion of cellulosic fiber material
US5053108A (en) * 1989-06-28 1991-10-01 Kamyr Ab High sulfidity cook for paper pulp using black liquor sulfonization of steamed chips
US5236553A (en) * 1989-06-28 1993-08-17 Kamyr Ab Continuous cooking with reduced horsepower and pulp degradation
AU639109B2 (en) * 1990-08-17 1993-07-15 Kamyr Inc. Sulfite modified continuous digesting
EP0477059A2 (de) * 1990-09-20 1992-03-25 Kvaerner Pulping Technologies AB Tränkung mit Schwarzlauge vor der Zufuhr der Weisslauge
EP0477059B1 (de) * 1990-09-20 1995-07-12 Kvaerner Pulping Technologies AB Tränkung mit Schwarzlauge vor der Zufuhr der Weisslauge
WO1993004232A1 (en) * 1991-08-23 1993-03-04 Kamyr Aktiebolag A process for the continuous digestion of cellulosic fiber material
US5529661A (en) * 1991-08-23 1996-06-25 Kvaerner Pulping Technologies Ab Process for controlling the flow of cellulosic fiber material through an impregnation vessel
US6113742A (en) * 1993-04-23 2000-09-05 Kvaerner Pulping Ab Digester having screening arrangement for isothermal cooking of fibrous material
US5766413A (en) * 1993-04-23 1998-06-16 Kvaerner Pulping Ab Process for isothermal cooking pulp in a continuous digester
US5536366A (en) * 1993-05-04 1996-07-16 Ahlstrom Machinery Inc. Digester system for implementing low dissolved solids profiling
EP1538256A3 (de) * 1993-11-08 2006-01-25 Andritz Inc Verwirklichung des Profils der gelösten Feststoffe
EP1538256A2 (de) * 1993-11-08 2005-06-08 Andritz Inc Verwirklichung des Profils der gelösten Feststoffe
US5674359A (en) * 1995-02-08 1997-10-07 Ahlstrom Machinery Inc. Continuous cooking of cellulosic fibrous material with cold alkali impregnation
US6544384B2 (en) 1995-06-02 2003-04-08 Andritz Inc. Pretreatment of chips before cooking
US6506283B2 (en) 1995-06-02 2003-01-14 Andritz Inc. Pretreatment of chips before cooking
US6248208B1 (en) 1995-06-02 2001-06-19 Andritz-Ahlstrom Inc. Pretreatment of chips before cooking
WO1997003244A1 (en) * 1995-07-12 1997-01-30 Kvaerner Pulping Ab Impregnation of fiber material
WO1997003243A1 (en) * 1995-07-12 1997-01-30 Kvaerner Pulping Ab Impregnation of fibre material
US6054019A (en) * 1995-07-12 2000-04-25 Kvaerner Pulping Ab Impregnation of fiber material in two subsequent concurrent impregnation zones
US5795438A (en) * 1996-11-04 1998-08-18 Ahlstrom Machinery Inc. Method and apparatus for feeding multiple digesters
US6024837A (en) * 1997-02-10 2000-02-15 Ahlstrom Machinery Inc. Low temperature gas phase continuous digester
US5882477A (en) * 1997-02-10 1999-03-16 Ahlstrom Machinery, Inc. Continuous digester with a low temperature gas-phase
US5985096A (en) * 1997-09-23 1999-11-16 Ahlstrom Machinery Inc. Vertical pulping digester having substantially constant diameter
US6123808A (en) * 1997-12-09 2000-09-26 Ahlstrom Machinery Inc. Distribution of dilution liquor to the discharge of a cellulose pulp digester
US6120647A (en) * 1998-01-26 2000-09-19 Ahlstrom Machinery Inc. Simplified liquid removal system for a cellulose pulp digester
US6468390B1 (en) * 1998-08-24 2002-10-22 Kvaerner Pulping Ab Method for continuous cooking of lignocellulosic fiber material
WO2005064078A1 (en) 2003-12-30 2005-07-14 Kvaerner Pulping Ab Feed of a mixture of chips and fluid from a low-pressure system to a high-pressure system
WO2006037860A1 (en) * 2004-10-04 2006-04-13 Metso Paper, Inc. Improved alkaline process and system for producing pulp
US20070256801A1 (en) * 2004-10-04 2007-11-08 Lasse Hernesniemi Alkaline Process and System for Producing Pulp
WO2009082338A1 (en) 2007-12-20 2009-07-02 Metso Fiber Karlstad Ab Method for kraft pulp production where hemicelluloses are returned
US20110100572A1 (en) * 2007-12-20 2011-05-05 Vidar Snekkenes Method for kraft pulp production where hemiculluloses are returned
US8273212B2 (en) * 2007-12-20 2012-09-25 Metso Paper Sweden Ab Method for kraft pulp production where hemicelluloses are returned
US10625190B2 (en) * 2014-06-26 2020-04-21 Valmet Ab Steam separation unit for a system for hydrolysis of lignocellulosic biomass material

Also Published As

Publication number Publication date
FI54155B (fi) 1978-06-30
FI54155C (fi) 1978-10-10
DE2112633A1 (de) 1971-09-30
FR2084755A5 (de) 1971-12-17
SE359331B (de) 1973-08-27
DE2112633C3 (de) 1973-12-20
DE2112633B2 (de) 1973-05-24
CA936309A (en) 1973-11-06
JPS5324521B1 (de) 1978-07-21
NO129361B (de) 1974-04-01

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