EP0407371A2 - Cuisson en continu À  coût, consommation d'énergie et dégradation de pâte réduits - Google Patents

Cuisson en continu À  coût, consommation d'énergie et dégradation de pâte réduits Download PDF

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Publication number
EP0407371A2
EP0407371A2 EP90890180A EP90890180A EP0407371A2 EP 0407371 A2 EP0407371 A2 EP 0407371A2 EP 90890180 A EP90890180 A EP 90890180A EP 90890180 A EP90890180 A EP 90890180A EP 0407371 A2 EP0407371 A2 EP 0407371A2
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EP
European Patent Office
Prior art keywords
vessel
digesting
impregnation
liquid
impregnation vessel
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.)
Withdrawn
Application number
EP90890180A
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German (de)
English (en)
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EP0407371A3 (en
Inventor
Johan C.F.C. Richter
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
Kamyr 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 Kamyr AB filed Critical Kamyr AB
Publication of EP0407371A2 publication Critical patent/EP0407371A2/fr
Publication of EP0407371A3 publication Critical patent/EP0407371A3/en
Withdrawn legal-status Critical Current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
    • D21C7/00—Digesters
    • D21C7/14—Means for circulating the lye
    • 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

Definitions

  • the internal impregnation vessel that is utilized in a number of the embodiments of said co-pending U.S. application serial number 07/200,204 was under full digester pressure, and therefore the shell, flanges, nozzles, pipes, etc. had to be dimensioned accordingly.
  • the actual internal impregnation vessel is also at digester pressure, however it comprises a non-pressurized tube since the pressure is the same on both sides of the vessel wall. Thus it is a mere standpipe, rather than a pressurized vessel (as in serial number 07/200,204).
  • the impregnation vessel according to the invention passes the liquid slurry of fibrous cellulosic material upwardly to a solids/liquid separator located adjacent the top of the digester. Liquid that is separated is passed downwardly in a conduit welded or otherwise attached to the impregnation vessel, to ultimately pass out the bottom of the vessel. In this way, the minimum mechanical action on the chips achieved with said co-pending application apparatus and method is also substantially possible, while other advantages accrue.
  • an apparatus for the continuous cooking of cellulosic fibrous material to produce paper pulp comprises the following elements: (a) A generally vertically disposed impregnation vessel having a bottom, and a top in open communication with the digester pressure. (b) Means for feeding a liquid slurry of cellulosic fibrous material to the bottom of the impregnation vessel. (c) A mechanical separating means disposed at the top of the impregnation vessel for separating cellulosic fibrous material from liquid, so as to decrease the liquid to material ratio of the slurry. (d) A generally vertically disposed digesting vessel having a top and a bottom, and an inlet at the top thereof.
  • a method of continuously digesting comminuted cellulosic fibrous material to produce paper pulp comprises the steps of substantially sequentially and continuously: (a) Feeding a liquid slurry of comminuted cellulosic fibrous material to the bottom of the impregnation vessel. (b) Flowing the material (at a temperature of about 100-120°C) upwardly in the impregnation vessel from the bottom to the top thereof, the impregnation vessel being open at the top to the digesting vessel pressure. (c) Separating some of the liquid from the slurry at the top of the impregnation vessel.
  • step (d) Moving the material from the bottom of the impregnation vessel to the top of the digesting vessel with a minimum of mechanical action on the material.
  • step (e) Withdrawing liquid separated in step (c) from the digesting vessel by passing it downwardly through the digesting vessel open to digesting vessel pressure out the bottom of the digesting vessel.
  • step (f) Digesting the material (at a temperature of about 160-170°C) in the digesting vessel, utilizing digesting liquid. And, (g) withdrawing pulp from the bottom of the digesting vessel.
  • FIGURE 1 a chips bin 10, preferably having an air lock 11 at the top thereof, has connections 12 for bin steaming by flash steam from flash tanks 25, 26, and leads to a chip meter 13, and low pressure feeder 14 into a chip chute 15 connected to the high pressure feeder 16.
  • Those components are variously connected to an in-line drainer 17, a level tank 18, a sand separator 19, and various other pipes and components, such as pumps 20, 21, 22, and 23, and to the conduit 24 to which white liquor is added.
  • Other conventional components include the flash tanks 25 and 26; heater 27 supplied with high pressure steam; pump 27′; white liquor input conduit 28; wash heater 29 supplied with high pressure steam; a pump 30; and a continuous vertical digester 32.
  • a generally vertically disposed impregnation vessel 34 having a bottom and a top in open connection with digester pressure.
  • Means are provided including the conduit 31 connected to the high pressure feeder 16, and all the other conventional apparatus illustrated, for feeding a liquid slurry of comminuted cellulosic fibrous material (wood chips) to the bottom of the vessel 34.
  • the vessel 34 is non-pressurized. It is held in place by welding it to the interior of the bottom of the digester 32 and is guided with gussets and/or tubes (not shown) at the top.
  • the bottom 35 of the digester 32 preferably is generally hemi-spherical. This reduces necessary plate thickness, and less deformation takes place too. It is also substantially devoid of packings compared to the prior art. Only short length packings are provided, and they preferably are of the male/female type rather than glands.
  • a conventional solids/liquid separator 36 is provided at the top of the tube 34, which is interior of the digester 32 and substantially concentric with it.
  • the separator 36 is of the same type as normally provided at the top of a digester, although its exact positioning and surrounding components are slightly different.
  • the separator 36 preferably comprises an internal helical screw 37 surrounded by a screen cylinder 38, and rotated by a motor 39.
  • a scraper 40 also rotates with the screw 39 to discharge slurried chips flowing out of the top of the tube 34 into the surrounding annular interior (inlet) of the digester 32. High pressure steam may be added at the top of digester 32.
  • the liquid that is separated by the separator 36 is withdrawn from the digester 32 by the non-pressurized conduit 41.
  • the conduit 41 is welded or otherwise attached to the tube 34, and carries the separated liquid through the entire height of the digester 32, to be discharged through the bottom 35, and to pass in line 42 to the high pressure pump 23 associated with the high pressure feeder 16.
  • the line 42 may be connected to a stationary screen (not shown) at the bottom of the tube 34 for pre-extraction, to facilitate any slight adjustments that are desired.
  • the digester 32 contains conventional screens 44 adjacent the top thereof, with a withdrawal conduit 45 leading to a pump 46 and an indirect heater 47.
  • the recirculated liquid withdrawn through screens 44 passes through conduit 48 and immediately contacts the chips as they are discharged out of the top of the tube 34 and distributed by the rotating scraper 40. Make-up white liquor is added in line 49.
  • withdrawal screens 51 are provided, which cooperate with a conduit 52 leading to a flash tank 25, and typically also to a flash tank 26.
  • the removed black liquor may be utilized for high sulfidity cooking.
  • annular withdrawal screens 53 which cooperate with the pump 27′ earlier described.
  • the heated withdrawn liquor is returned via conduct 54 to the internal conduit 55.
  • the conduit 55 rather than being “hung” in the digester as is conventional in continuous digesters, is welded or otherwise attached to the exterior of the tube 34, and liquid therefrom is discharged back into the chips column at 56, which is preferably at least a semi-annular header.
  • a plurality of such interior conduits 55 may be provided for returning recirculated liquid.
  • Adjacent the bottom of the digester 32 are wash withdrawal screens, cooperating with the heater 29 and pump 30 earlier described.
  • rotating mini-scrapers 59 preferably are provided, which assist in forcing the pulp into the outlet 61, forked to a nozzle 62 (see FIGURE 2) on either side of tube 34.
  • FIGURE 3 embodiment is similar to the FIGURE 1 embodiment, and like components are shown by like reference numerals only preceded by a "1". Only the components which are significantly different will be described with respect to the FIGURE 2 embodiment.
  • a lower chips bin 70 is provided below the chips bin 110, with vibrator 71, 72 for the bins 110, 70, respectively.
  • the bin 72 is connected to a vertical vessel 74 having steam at the top thereof, and establishing a liquid level 75.
  • the comminuted cellulosic fibrous material e.g. wood chips
  • the comminuted cellulosic fibrous material is slurried in the vessel 74. It is discharged from the vessel 74 utilizing the rotating bottom scraper 76 into the conduit 77 attached to the high pressure feeder 116.
  • the lines 80, 81, 82, and 83 provide for the supply of steam and/or black liquor to the vessel 74.
  • Steam from flash tank 125 passes through conduit 82 to the chips bin 110, and separated black liquor passes in conduit 83 to the vessel 74 to provide part of the slurrying liquid.
  • the slurrying liquid is withdrawn, to a large extent, at the high pressure feeder 116, passing through sand separator 119 to line 80 which returns the black liquor to evaporators and/or recovery.
  • Some of the black liquor may be diverted from line 80, via line 81, to the vessel 74 to provide additional slurrying liquid where necessary.
  • the conduit 84 maybe provided to cause black liquor separated at the flash tank 125 to pass straight to the line 85 extending to the evaporators/recovery area, rather than being used as slurrying liquid.
  • the digester 32, 132 may either be a hydraulic digester or a steam phase digester.
  • a steam phase digester 32 is shown in FIGURE 1, and a hydraulic digester 132 in FIGURE 3.
  • a method of continuously digesting comminuted cellulosic fibrous material to produce paper pulp is provided, which method will be described with respect to FIGURE 1.
  • a liquid slurry from chute 15 of comminuted cellulosic fibrous material is fed via line 31 in high pressure feeder 16 to the bottom of the impregnation vessel 34.
  • the material is caused to flow upwardly in the vessel 34 from the bottom to the top thereof.
  • Some of the liquid is separated from the slurry at the top of the tube 34 by the separator 36.
  • the material is moved from the bottom of the vessel 34 to the top of the digester 32 with a minimum of mechanical action on the material, with the vessel 34 open at the top to the digesting vessel 32 pressure.
  • Liquid separated by the separator 36 is withdrawn from the digesting vessel 32 by passing it downwardly through the vessel 32 in conduit 41, open to digester pressure at the top of conduit 41, out the bottom of the digester 32, to return conduit 42 to the high pressure feeder pump 23.
  • the chips are digested in the digester 32 utilizing digesting liquid (white liquor), and the produced pulp is withdrawn through conduit 61 at the bottom of the vessel 32.
  • the digesting liquor is provided at least in part through conduit 55, attached to the tube 34, and entering the chips column at point 56.
  • the temperature of the material is maintained at between about 100-120°C.
  • the temperature is maintained between about 160-170°C.
  • the produced pulp will have less degradation than conventionally, and is produced at less cost and horsepower.

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  • Paper (AREA)
EP19900890180 1989-06-28 1990-06-07 Continuous cooking with reduced cost, horsepower and pulp degradation Withdrawn EP0407371A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US37265089A 1989-06-28 1989-06-28
US372650 1989-06-28

Publications (2)

Publication Number Publication Date
EP0407371A2 true EP0407371A2 (fr) 1991-01-09
EP0407371A3 EP0407371A3 (en) 1991-11-27

Family

ID=23469091

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900890180 Withdrawn EP0407371A3 (en) 1989-06-28 1990-06-07 Continuous cooking with reduced cost, horsepower and pulp degradation

Country Status (7)

Country Link
EP (1) EP0407371A3 (fr)
JP (1) JPH0333287A (fr)
BR (1) BR9003023A (fr)
DE (1) DE407371T1 (fr)
FI (1) FI903207A7 (fr)
NO (1) NO902849L (fr)
SE (1) SE506456C2 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994010372A1 (fr) * 1992-11-02 1994-05-11 Kamyr, Inc. Refroidissement de la ligne de circulation superieure pour lessiveur modifie
WO1995034712A1 (fr) * 1994-06-16 1995-12-21 Kamyr, Inc. Alimentation amelioree de copeaux dans un lessiveur continu

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE525692A (fr) * 1952-05-14
NL136526C (fr) * 1959-11-20
GB1042381A (en) * 1963-01-08 1966-09-14 Defibrator Ab Apparatus for use in the production of pulp from lignocellulose-containing material
US5300195A (en) * 1988-05-31 1994-04-05 Kamyr Ab Continuous vertical digester apparatus

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994010372A1 (fr) * 1992-11-02 1994-05-11 Kamyr, Inc. Refroidissement de la ligne de circulation superieure pour lessiveur modifie
WO1995034712A1 (fr) * 1994-06-16 1995-12-21 Kamyr, Inc. Alimentation amelioree de copeaux dans un lessiveur continu
US5700355A (en) * 1994-06-16 1997-12-23 Ahlstrom Machinery Inc. Chip feeding for a continuous digester

Also Published As

Publication number Publication date
SE9001782L (sv) 1990-12-29
FI903207A7 (fi) 1990-12-29
FI903207A0 (fi) 1990-06-26
JPH0333287A (ja) 1991-02-13
NO902849D0 (no) 1990-06-27
DE407371T1 (de) 1991-10-17
SE506456C2 (sv) 1997-12-15
NO902849L (no) 1991-01-02
SE9001782D0 (sv) 1990-05-17
EP0407371A3 (en) 1991-11-27
BR9003023A (pt) 1991-08-20

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