WO1985001305A1 - Procede de remplissage d'un lessiveur - Google Patents

Procede de remplissage d'un lessiveur Download PDF

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Publication number
WO1985001305A1
WO1985001305A1 PCT/FI1984/000067 FI8400067W WO8501305A1 WO 1985001305 A1 WO1985001305 A1 WO 1985001305A1 FI 8400067 W FI8400067 W FI 8400067W WO 8501305 A1 WO8501305 A1 WO 8501305A1
Authority
WO
WIPO (PCT)
Prior art keywords
digester
liquid
filling
chips
opening
Prior art date
Application number
PCT/FI1984/000067
Other languages
English (en)
Inventor
Seppo Hiljanen
Original Assignee
Rauma-Repola Oy
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 Rauma-Repola Oy filed Critical Rauma-Repola Oy
Publication of WO1985001305A1 publication Critical patent/WO1985001305A1/fr

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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
    • D21C7/00—Digesters
    • D21C7/06—Feeding devices

Definitions

  • the present invention is concerned with a method for filling a batch digester for pulp as well as with a batch digester to be used in the method.
  • the invention can be utilized in prior-art batchwise pulp cooking processes.
  • Batch cooking of pulp is the oldest mode in use for chemical defibration of chips or of other material.
  • the digesters require expensive decks and, in the upper part or at the top of the digester, operating levels and support structures supporting the distributor equipment. For winter conditions, a building must usually be constructed for the top portion of the digester.
  • the cooking liquor is added into the digester, and the contents in the digester are heated to the cooking temperature.
  • the digester is emptied through a so-called blow valve placed at the bottom.
  • the power required for the removal of the pulp is obtained either from the pulp being removed as hot and pressurized, or the digester is pressurized, e.g., by means of compressed air or steam before blowing, or the contents of the digester are pumped from the digester into a blow tank. In connection with the pumping, it is possible to use additional dilution.
  • the object of the present invention is to provide a new system for batch cooking of pulp, wherein the filling of the digester has been arranged in a more simple way than in prior-art methods.
  • the material to be defibrated in a batch process is mixed with a liquid outside the digester, and the mixture obtained in this way is introduced into the digester as one flow.
  • the mixing liquid consists in particular of the liquor that is used in the first stage of the cook.
  • the mixture of the material to be defibrated and the liquid is introduced into the digester preferably so that most of the feed takes place to underneath the liquid level formed in the digester.
  • the batch digester in accordance with the invention is a digester that is provided with a filling opening through which the material to be defibrated, mixed with liquid, is introduced into the digester.
  • the opening is located in particular below the liquid level formed in the digester, and thereat most appropriately so that the filling opening and the opening for the removal of the digested pulp form one opening.
  • the chips and the liquid are preferably fed into the digester through its bottom end.
  • the chips are usually of lower weight than the liquid, whereat the digester starts being filled so that the chips are packed as a column first in the top portion of the digester and from there downwards as more chips are coming in. If the chips are heavier than the liquid, the flow can be controlled so that it takes the chips along with the flow into the top portion of the digester.
  • the evacuation of air from the top end of the digester is natural as the filling takes place from the bottom end.
  • the liquid used for filling is also readily foaming, whereby the filling through the bottom end is a good way of avoiding foaming.
  • filling from the bottom upwards is also lower than if the filling took place in the opposite direction.
  • filling from the top may also be used very well.
  • the top end of the digester is usually also provided with a screen, through which liquid can be removed during the filling.
  • the removal of the pulp from the digester is simplest and most reliable when it is accomplished through the bottom part of the digester, as it is also accomplished to-day.
  • Figure 1 shows a digester to be used in the method.
  • Figure 2 shows a detail of an alternative digester, and Figures 3 and 4 show certain cooking processes to which the invention has been applied.
  • a screen 9 for the removal of any excessive filling liquid and for the suction of the cooking circulation 10.
  • the excessive filling liquid is preferably removed through the same opening as the cooking circulation.
  • the gases are removed through the opening 11, which may also be used for the removal of the excessive liquid.
  • the bottom end is provided with a blowing bow 12, to which the supply 13 of the chips into the same opening 14 is also introduced.
  • the mixture of chips and liquid may also be introduced into the digester by means of a separate connection, located at a position different from that of the conduit for emptying, preferably, however, in the bottom portion of the digester. In such cases, there is, however, no reason why it could not be introduced into the digester through the same conduit through which the pulp is removed.
  • the chips are not introduced into the digester as mixed with liquid or if the liquid is used as an aid for packing by mixing the liquid with the chips falling down into the digester, it is necessary that the filling opening is placed at the top portion of the digester. In such a case, it is necessary that there is a separate opening for the removal of the pulp at the bottom of the digester.
  • openings and conduits By the said openings and conduits is meant the openings and conduits on the digester that are required by the process.
  • Fig. 2 shows a second mode of locating the screens 15 intended for the removal of excessive liquid.
  • the mixture 16 of chips and liquid is fed into the digester through the bottom of the bottom cone 17, and the excessive liquid 18 is recirculated in order to fetch fresh chips.
  • the chips are pushed into the digester, by-passing the screens.
  • the warm black liquor 5 is mixed with the chips 6 in a separate tank 3 and pumped in through the bottom end of the digester 1.
  • the digester is filled with a mixture of chips and liquor, whereat any excessive liquor starts flowing out through the screens 2 at the top end and is passed back into the storage tank 4 for warm liquor.
  • the pumping is continued until the digester has been filled with chips and reached an appropriate degree of packing with chips.
  • the black liquor is displaced through the screens at the top end by means of a mixture of hot black liquor and white liquor, and the cooking process is continued in the desired way (see, e.g., Swedish published Patent Application No. 82-013,343).
  • the prehydrolysis water, to which chemicals may have been added, and the chips 6 are mixed 3 outside the digester 1 and the mixture is pumped into the digester through its bottom end. Any excessive water is returned through the screens 2, upon filling of the digester, in order to fetch fresh chips.
  • the prehydrolysis cooking is performed, the hydrolysate is removed, and the cooking process is continued in accordance with the desired sequence.
  • the method of the invention is also excellently suitable for cooking processes in which, in the first stage, an absorption or heating treatment of the chips is performed at the normal atmospheric pressure.
  • this treatment can be performed in an ordinary vessel outside the digester, whereat only the cooking proper at a high temperature and under high pressure remain to be performed in the digester. In this way, the overall duration of the cooking cycle in the high-cost digester can be reduced.

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  • Paper (AREA)

Abstract

Procédé de remplissage d'un lessiveur pour pulpe, où le matériau à défibrer est mélangé avec un liquide à l'extérieur du lessiveur et est introduit dans le lessiveur une fois mélangé avec ce liquide. Le lessiveur est rempli de préférence par l'ouverture (14) permettant le retrait de la pulpe.
PCT/FI1984/000067 1983-09-21 1984-09-21 Procede de remplissage d'un lessiveur WO1985001305A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FI833381A FI833381A0 (fi) 1983-09-21 1983-09-21 Saett foer att ifylla diskontinuerlig kokare med flis
FI833381 1983-09-21
ZA848066A ZA848066B (en) 1983-09-21 1984-10-16 Method for filling a batch digester

Publications (1)

Publication Number Publication Date
WO1985001305A1 true WO1985001305A1 (fr) 1985-03-28

Family

ID=26157499

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/FI1984/000067 WO1985001305A1 (fr) 1983-09-21 1984-09-21 Procede de remplissage d'un lessiveur

Country Status (3)

Country Link
FI (1) FI833381A0 (fr)
WO (1) WO1985001305A1 (fr)
ZA (1) ZA848066B (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2571757A1 (fr) * 1984-10-16 1986-04-18 Rauma Repola Oy Procede pour le remplissage d'un digesteur de copeaux a marche discontinue et digesteur pour ce procede
WO1991006702A1 (fr) * 1989-10-30 1991-05-16 Beloit Corporation Methode et appareil pour deplacer les liqueurs epuisees dans un digesteur
US5080757A (en) * 1989-10-30 1992-01-14 Beloit Corporation Method to displace a digester from both ends
WO2012006396A1 (fr) * 2010-07-07 2012-01-12 Andritz Inc. Système d'introduction de copeaux et d'étuvage et procédé pour lessiveur en discontinu

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA823900A (en) * 1969-09-30 A. Carlsmith Lawrence Continuous digester wood chip level control
SE334809B (fr) * 1969-09-29 1971-05-03 Kamyr Ab

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA823900A (en) * 1969-09-30 A. Carlsmith Lawrence Continuous digester wood chip level control
SE334809B (fr) * 1969-09-29 1971-05-03 Kamyr Ab

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Derwent's abstract No. 59 922 D/33, SU 777 122 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2571757A1 (fr) * 1984-10-16 1986-04-18 Rauma Repola Oy Procede pour le remplissage d'un digesteur de copeaux a marche discontinue et digesteur pour ce procede
WO1991006702A1 (fr) * 1989-10-30 1991-05-16 Beloit Corporation Methode et appareil pour deplacer les liqueurs epuisees dans un digesteur
US5059284A (en) * 1989-10-30 1991-10-22 Beloit Corporation Apparatus to displace a digester from both ends
US5080757A (en) * 1989-10-30 1992-01-14 Beloit Corporation Method to displace a digester from both ends
WO2012006396A1 (fr) * 2010-07-07 2012-01-12 Andritz Inc. Système d'introduction de copeaux et d'étuvage et procédé pour lessiveur en discontinu

Also Published As

Publication number Publication date
FI833381A0 (fi) 1983-09-21
ZA848066B (en) 1985-12-24

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