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WO1998035089A1 - Procede et dispositif permettant de prechauffer et d'impregner une matiere cellulosique - Google Patents

Procede et dispositif permettant de prechauffer et d'impregner une matiere cellulosique Download PDF

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Publication number
WO1998035089A1
WO1998035089A1 PCT/SE1997/000193 SE9700193W WO9835089A1 WO 1998035089 A1 WO1998035089 A1 WO 1998035089A1 SE 9700193 W SE9700193 W SE 9700193W WO 9835089 A1 WO9835089 A1 WO 9835089A1
Authority
WO
WIPO (PCT)
Prior art keywords
space
pressure
temperature
bar
liquid
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.)
Ceased
Application number
PCT/SE1997/000193
Other languages
English (en)
Swedish (sv)
Inventor
Lennart Gustavsson
Vidar Snekkenes
Torbjörn CARLSSON
Bo SVANEGÅRD
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.)
Metso Fiber Karlstad AB
Original Assignee
Kvaerner Pulping AB
Kvaerner Pulping Technologies AB
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 AB, Kvaerner Pulping Technologies AB filed Critical Kvaerner Pulping AB
Priority to PCT/SE1997/000193 priority Critical patent/WO1998035089A1/fr
Priority to AU21837/97A priority patent/AU2183797A/en
Publication of WO1998035089A1 publication Critical patent/WO1998035089A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/02—Pretreatment of the raw materials by chemical or physical means
    • D21B1/021—Pretreatment of the raw materials by chemical or physical means by chemical means
    • 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
    • D21C1/02—Pretreatment of the finely-divided materials before digesting with water or steam
    • 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 a method and an apparatus for heating and impregnating treatment of a comminuted fibre material, before chemical digestion of the material to paper pulp.
  • a so called steaming process is used in today's modern pulp mills, in which process the chips are firstly exposed to steam treatment in an atmospheric chip bin, whereafter the chips, via a so called low pressure feeder, are conveyed to a steaming vessel for additional steam treatment.
  • the heat transfer is dependent on the difference in temperature between chips and steam.
  • the heating process is thus asymptotic in time.
  • the heat transfer coefficient in chips and fibre affects the time factor of the heat transfer in a negative way.
  • the object of the invention is thus to achieve a method for treatment of comminuted fibre material before chemical digestion of the material, whereby the material, (a) in a first step is heated, preferably by addition of steam, in a gas atmosphere with a pressure (PI) and a temperature (Tl), (b) in a second step has air extracted from it, in a gas atmosphere with a pressure (P2) and a temperature (T2), where (T1)>(T2) and (P2) is sufficiently lower than (PI) to extract air from the material, (c)in a third step is soaked in impregnation liquid, where said first step (a) is performed in a first space and said second step (b) is performed in a second space.
  • the material is added to this second space in such a way that it is exposed to a lowering in the pressure, when it is transferred from the first space to the second space.
  • the impregnation liquid with a temperature (T3) is added to the material in sequentially direct connection to a retention time in the gas atmosphere (P2, T2) in said second space.
  • said first and second spaces consists of separate vessels.
  • the chips are thus, in the method according to the invention, heated in a first step at a pressure PI, which preferably is atmospheric, with for example low pressure steam to a temperature Tl of about 100°C.
  • the heating can, alternatively take place at a pressure PI, which is greater than atmospheric pressure, and is in that case driven to a temperature Tl at about 120-130°C.
  • the heating suitably takes place during a time interval of below 5 minutes, preferably below 4 minutes and even more preferred below 3 minutes, when the method is pressurised.
  • the partial pressure for the air/gas-mixture is thus reduced, preferably fast, and the gas is conducted away. Thereby, arises preferably an underpressure in the second step.
  • the pressure is then 1 bar (abs)>P2>0.3 bar (abs) and the temperature T2 is somewhat lower than in the first step.
  • the moist in the cavities of the chip pieces will, depending upon the degree of lowering of the pressure, flash, whereby air is extracted and replaced with saturated steam.
  • T3 colder
  • the lowering of the pressure in connection with the transferring of the material to the second space not is driven to an underpressure, whereby P2 is a slight overpressure or an atmospheric pressure. It is though essential that the pressure P2 is adequately lower than PI in order to be able to extract air from the fibre material.
  • the pressure difference is suitably within the range 0.01-1.0 bar, preferably 0.02-0.7 bar and even more preferably 0.1-0.5 bar.
  • Said lowering of the pressure is, when said first and second spaces do not consist of separate vessels, conducted so that P2 only is marginally lower than PI.
  • the lowering of the pressure is hereby not sudden, but is rather based on a pressure drop over the bed of chip pieces.
  • the invention also comprises an apparatus for treatment of comminuted fibre material before chemical digestion of the material, comprising a vessel with devices for addition of steam, which vessel is operatively connected with a sluice device for feeding the material to a vertical chute with devices for sustaining levels of chips and liquid therein, whereby said sluice device passes the fibre material through a lock, from a higher pressure to a lower pressure.
  • the chip bin in a preferred embodiment, can be manufactured considerably cheaper, since it can be made smaller and without steam addition.
  • Other advantages in the equipment is that no gas tight feeding screw or fan is needed.
  • the piping and instrumenting will also be less extensive than in a conventional system.
  • the invention also gives environment related advantages with, for example, lowered discharges of badly smelling compounds.
  • Figure 1 Shows a diagram over the principle of a preferred embodiment of the method according to the invention.
  • Figure 2 Shows a possible set of apparatus to conduct a method according to the invention.
  • Figure 3 Shows yet a possible set of apparatus to conduct a method according to the invention, where the first and the second spaces are contained within the same vessel.
  • the detail 1, shown in figure 1, symbolises the first step according to the invention.
  • the detail 1, consists, in the preferred case, of a chip bin, whereby there is no need for a steaming vessel in the system.
  • the chips are, in this first step, thus heated at a pressure PI, which preferably is atmospheric, with, for example, low pressure steam, to a temperature Tl of about 100°C.
  • the heating takes place during a time interval of about 5-15 minutes.
  • the partial pressure for the air/gas-mixture is thus quickly reduced, and the gas is conducted away with the aid of a vacuum pump (not shown) , which via a tubular screen (not shown) is connected to a outlet conduit 11. Thereby, arises an underpressure in the second step.
  • the pressure is thereby preferably 1 bar (abs)>P2>0.3 bar (abs) and the temperature T2 is somewhat lower than in the first step.
  • the moist in the cavities of the chip pieces will, depending upon the degree of lowering of the pressure, flash, whereby air is extracted and replaced with saturated steam.
  • the continuously operating apparatus set shown in figure 2 comprises a vertical chip bin 1, a horizontal steaming vessel 2 and a vertical chip chute 3. Chip are fed into the upper part of the chip bin, which is atmospheric and, in a preferred embodiment without steam addition, which means that it has a function of mainly being a buffer for a steady flow.
  • the chips are measured in, with the aid of a chip meter 4, via a low pressure feeder 5 into the steaming vessel 2.
  • Low pressure steam preferably from one of the digester flashes 18, is added to the steaming vessel, through a conduit 6, and condensate is withdrawn through a conduit 7 for promotion to the condensate handling system of the mill.
  • the low pressure feeder 5 and the steaming vessel 2 are degassed with aid of the conduits 8 and 9.
  • the chips leave the vessel, after a retention time of some minutes, in order to be passed through a lock, by a second low pressure feeder 10, down into the chip chute 3.
  • Levels of chip and liquid are sustained in the chip chute, which assures a steady and air free feeding via a high pressure feeder 12, to the following high pressure system for preimpregnation and cooking of the chips.
  • the chips are, in connection with the feeding into the chute, exposed to a sudden lowering in the pressure of preferably 0.1-0.5 bar.
  • the desired pressure P2 in the chute is sustained with the aid of a condensor 19, which is connected to an outlet conduit 11.
  • One end of the outlet conduit opens out at the upper part of the chute, whereby the mouth always can be above said level of liquid.
  • the conduit 17 is part of a circulation with aid of which the liquid level in the chute is sustained. Liquid is, thereby, pumped from the high pressure feeder, via a sand trap 14 and a tubular screen 15, back to the chute.
  • the liquid pool in the bottom part of the chute holds a temperature T3, which is lower than the temperature T2 of chips and gas phase that is present above the liquid level.
  • the low pressure feeder can, if so is required, be followed by a feeding screw which the fibre material must pass before it falls down into the chute.
  • the pressure in the screw space is hereby the same as in the chute.
  • the object of the screw when such is existing, is to give the chips a certain retention time before it falls down into the colder liquid. In this way it is assured that there is time for adequate air extraction.
  • An alternative to a condensor is that the outlet conduit also comprises an inlet opening for addition of impregnation liquid. It is, in that case, the conduit 17, or a constituent conduit from this conduit, that opens out in the outlet conduit.
  • a vertical chip bin 1 is shown in figure 3, to which chip pieces are fed in the top and fed out from the bottom.
  • steam 20 fresh steam and/or steam from one of the digester flashes 18
  • the chip pieces are, through the main steam addition at the level 20a, heated in the space la, which stretches from the level 20a and upwards, but preferably not all the way up to the chip level, at a pressure PI, which is near atmospheric pressure, to a temperature Tl of about 100°C.
  • the lower part of the chip bin constitutes the second space lb according to the invention.
  • An outlet conduit 11, which is connected to a condensor 19, is connected to the second space lb. Thereby is brought about, in the part of the second space lb which is closest to the connected outlet conduit, a gas atmosphere with a pressure P2, which is marginally lower than PI, and a temperature T2, which is circa 1-2°C lower than Tl.
  • the pressure in the remaining part of the second space lb is also lower than PI, whereby the is a gradient form the entry of the chip pieces into the space lb, to their feeding out through the feeding device 4.
  • This feeding out device 4 is situated in the bottom of the chip bin.
  • the space lb is, in the construction that is shown in figure 3, protruding, in one of its ends, in relation to the remaining part of the chip bin.
  • the outlet conduit 11 is thereby connected to the top of the protruding part and the feeding out device 4 is connected to the bottom of this part.
  • the chip pieces fall, due to this construction, from the chip column that is present in the upper part of the chip bin, diagonally down towards the feeding out device, whereby a space, which is in the main free from chips, arises in the upper part of the protruding part of the second space lb. It is, thus, to this space which is free from chips, that the outlet conduit 11 is connected.
  • a feeding screw is connected to the bottom of the chip bin and that it, to the upper part of this screw, preferably at the end of it, is connected a second space according to the invention, with a belonging outlet conduit 11.
  • Said first and second spaces according to the invention will thus, as in the embodiments according to figures 1 and 2, thereby, be constituted of separate vessels.
  • the invention is not limited by the embodiment described above, but can be varied within the scope of the claims.
  • the steaming vessel 2 can, thus, for example, also be atmospheric.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Paper (AREA)

Abstract

L'invention concerne un procédé et un appareil de traitement d'une matière fibreuse broyée avant son lessivage chimique. Selon ce procédé: (a) dans un premier temps, la matière est chauffée, de préférence par addition de vapeur, dans une atmosphère gazeuse à une pression (P1) et à une température (T1); (b) dans un deuxième temps, de l'air est extrait de la matière dans une atmosphère gazeuse à une pression (P2) et à une température (T2), sachant que (T1) > (T2) et (P2) est suffisamment inférieure à (P1) pour permettre l'extraction d'air de la matière; (c) dans un troisième temps, la matière est imbibée d'un liquide d'imprégnation. La première opération (a) est réalisée dans un premier espace (1, 2, 1a) et la deuxième opération (b) dans un deuxième espace (3, 1b). La matière est ajoutée dans ce deuxième espace de manière à être soumise à une baisse de pression en passant du premier au deuxième espace. Ledit liquide d'imprégnation est ajouté, à une température (T3), à ladite matière en relation directe, de façon séquentielle, avec un temps de rétention dans l'atmosphère gazeuse (P2, T2) du deuxième espace.
PCT/SE1997/000193 1997-02-07 1997-02-07 Procede et dispositif permettant de prechauffer et d'impregner une matiere cellulosique Ceased WO1998035089A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
PCT/SE1997/000193 WO1998035089A1 (fr) 1997-02-07 1997-02-07 Procede et dispositif permettant de prechauffer et d'impregner une matiere cellulosique
AU21837/97A AU2183797A (en) 1997-02-07 1997-02-07 Method and apparatus for preheating an impregnating cellulosic material

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SE1997/000193 WO1998035089A1 (fr) 1997-02-07 1997-02-07 Procede et dispositif permettant de prechauffer et d'impregner une matiere cellulosique

Publications (1)

Publication Number Publication Date
WO1998035089A1 true WO1998035089A1 (fr) 1998-08-13

Family

ID=20405504

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1997/000193 Ceased WO1998035089A1 (fr) 1997-02-07 1997-02-07 Procede et dispositif permettant de prechauffer et d'impregner une matiere cellulosique

Country Status (2)

Country Link
AU (1) AU2183797A (fr)
WO (1) WO1998035089A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005106112A1 (fr) * 2004-05-05 2005-11-10 Metso Paper, Inc. Procede et appareil d'elimination des gaz d'un materiau particulaire
WO2009149958A1 (fr) * 2008-06-13 2009-12-17 Betz Guenter Dispositif d'imprégnation d'un matériau fibreux à l'aide d'un liquide
CN109972452A (zh) * 2017-12-28 2019-07-05 北京小池原品科技有限公司 一种本色竹浆浆料生活用纸的制备方法

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE152117C1 (fr) *
SE169725C1 (fr) *
US3215587A (en) * 1963-01-21 1965-11-02 Lummus Co Continuous process and apparatus for delignification of cellulosic material
US3278367A (en) * 1963-02-14 1966-10-11 Aqua Chem Inc Method of producing wood pulp including steaming, vacuum, and impregnation
US3294625A (en) * 1963-03-28 1966-12-27 Lummus Co Method for impregnating cellulosic material
WO1995009267A1 (fr) * 1993-09-29 1995-04-06 Antti Aho Pretraitement de copeaux de bois

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE152117C1 (fr) *
SE169725C1 (fr) *
US3215587A (en) * 1963-01-21 1965-11-02 Lummus Co Continuous process and apparatus for delignification of cellulosic material
US3278367A (en) * 1963-02-14 1966-10-11 Aqua Chem Inc Method of producing wood pulp including steaming, vacuum, and impregnation
US3294625A (en) * 1963-03-28 1966-12-27 Lummus Co Method for impregnating cellulosic material
WO1995009267A1 (fr) * 1993-09-29 1995-04-06 Antti Aho Pretraitement de copeaux de bois

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2005106112A1 (fr) * 2004-05-05 2005-11-10 Metso Paper, Inc. Procede et appareil d'elimination des gaz d'un materiau particulaire
WO2009149958A1 (fr) * 2008-06-13 2009-12-17 Betz Guenter Dispositif d'imprégnation d'un matériau fibreux à l'aide d'un liquide
US8414740B2 (en) 2008-06-13 2013-04-09 Günter Betz Apparatus for impregnating fibrous material with a liquid
CN102057103B (zh) * 2008-06-13 2013-07-24 京特·贝茨 用于通过流体润湿纤维材料的装置
KR101540833B1 (ko) * 2008-06-13 2015-07-30 귄터 베쯔 섬유 물질에 액체를 스며들게 하는 장치
CN109972452A (zh) * 2017-12-28 2019-07-05 北京小池原品科技有限公司 一种本色竹浆浆料生活用纸的制备方法

Also Published As

Publication number Publication date
AU2183797A (en) 1998-08-26

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