WO1990006395A1 - Appareil pour le traitement continu de pâte de cellulose - Google Patents

Appareil pour le traitement continu de pâte de cellulose Download PDF

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Publication number
WO1990006395A1
WO1990006395A1 PCT/SE1989/000650 SE8900650W WO9006395A1 WO 1990006395 A1 WO1990006395 A1 WO 1990006395A1 SE 8900650 W SE8900650 W SE 8900650W WO 9006395 A1 WO9006395 A1 WO 9006395A1
Authority
WO
WIPO (PCT)
Prior art keywords
vessel
gas
pulp
conduit
tank
Prior art date
Application number
PCT/SE1989/000650
Other languages
English (en)
Inventor
E. Bertil Berg
Per-Olov Lindblad
Olof Simonson
Alf LINDSTRÖM
Original Assignee
Sunds Defibrator Industries Aktiebolag
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 Sunds Defibrator Industries Aktiebolag filed Critical Sunds Defibrator Industries Aktiebolag
Publication of WO1990006395A1 publication Critical patent/WO1990006395A1/fr
Priority to NO912008A priority Critical patent/NO912008D0/no
Priority to FI912522A priority patent/FI912522A0/fi

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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
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor

Definitions

  • This invention relates to the processing of pulp with an activating chemical in gas phase, preferably nitrogen dioxide, and a gas containing oxygen, and it also relates to an apparatus for carrying out said processing.
  • Pulp is processed with nitrogen dioxide and oxygen gas as a pre-treatment prior to alkaline oxygen gas deligni- fication. It was thereby found that the supply of nitrogen dioxide and oxygen gives rise to several different chem ⁇ ical reactions in the pulp. In order to obtain a positive result from these reactions, the treatment must be divid ⁇ ed into at least two phases. In the first phase, the nitrogen dioxide shall react with the pulp without the presence of oxygen gas. The second reaction phase, how ⁇ ever, shall take place in the presence of oxygen gas, which can be supplied as pure oxygen or as a gas contain ⁇ ing oxygen.
  • the present invention implies that optimum conditions for the processing of pulp can be obtained in a single gas-tight vessel with nitrogen dioxide and oxygen gas.
  • the apparatus shown comprises a gas-tight vessel 1, which upwardly is provided with a feed device 2 for gas-tight infeed of pulp.
  • the device 2 preferably is a screw 3, through which the pulp is supplied in the form of a gas-tight plug.
  • a special device 4 is provided at the bottom of the vessel 1 .
  • Said device preferably comprises a tank 6 in direct connection with the vessel 1, in which tank 6 a dilut ⁇ ion zone is maintained with an outlet 7 below the liquid level.
  • the vessel 1 further is divided into an upper portion 8 and a lower portion 9- These two portions may have the same diameter, or the diameter of the lower portion may be greater.
  • the diameter of the lower portion preferably is 10-40.2 and suitably 20-30$ greater than the diameter of the upper portion.
  • the upper portion 8 comprises a mixing zone 10 and a reaction zone 11.
  • the pulp level in the reaction zone is indicated by a level transmitter 12.
  • a conduit 13 for the supply of nitrogen dioxide is connected to the mixing zone 10 at the top of the vessel 1.
  • a conduit 14 for the recycling of gas is connected between the discharge device 5 and vessel 1 in the transition between the upper portion 8 and lower portion 9- Gas is supplied preferably symmetrically about the periphery of the vessel.
  • a fan 15 is located for ensuring the gas flow.
  • a conduit 16 for the supply of oxygen gas is connected to said recycling conduit 14.
  • the oxygen gas can be supplied as pure oxygen or as a gas containing oxagen.
  • the vessel 1 extends downward in the tank 6 of the discharge device 5 so that a space 17 is formed above the dilution zone between the outer surface of the wall of vessel 1 and the tank wall 6.
  • the conduit 14 for the recycling of gas is connected to said space 17.
  • an opening 18 extending all about is located, through which the processed pulp is intended to be discharged by means of a rotary scraping device 19 to the surrounding tank 6.
  • the entire bottom can be designed as a rotary conic disc, on which the entire pulp bed is resting. The discharge there takes place at the periphery of the disc.
  • other discharge types can be imagined, for example screw discharge.
  • the tank 6 is arranged to receive the pulp from the vessel 1 and is provided with dilution nozzles 20, which are arranged tangentially in order to cause the pulp to rotate simultaneously with the dilution.
  • the tank can also be formed with a screw-shape passageway direct ⁇ ed downward to the outlet 7 .
  • a separate after-reaction vessel 21 may possibly be provided after the vessel 1, and a pump 22 be provided to pump the pulp directly from the vessel to said separate vessel 21.
  • the pulp processed in the apparatus according to the invention shall be manufactured chemically, preferably sulphate pulp, but also other chemical pulps can be used.
  • Pulp with a concentration of 20-35$ is supplied to the vessel 1 through the feed device 2 in such a manner, that gas is prevented to leak out. Air at the same time is prevented from following along with the pulp into the vessel 1.
  • the pulp upon its entering the vessel 1 is disinte ⁇ grated by the device 4 and allowed to fall down through the mixing zone 10 in the upper portion 8 of the vessel 1.
  • There nitrogen dioxide is admixed whic is supplied through the conduit 13 in an amount of 10-20 kg/ton pulp.
  • the level for the pulp bed in the vessel 1 is determined by means of the level transmitter 12.
  • the reaction zone 11 the reaction between the nitrogen dioxide and pulp starts. In this zone the pulp and gas are moved continuously down at substantially the same speed, i.e. the nitrogen dioxide included in the pulp does not move in relation to the pulp.
  • the pulp After the reaction zone 11 in the upper portion 8 of the vessel 1 the pulp enters the lower portion 9 of the vessel. There gas is supplied through the conduit 1 .
  • This gas consists of recycled residue gas, which was separ ⁇ ated from the pulp in the discharge device 5 , mixed with oxygen gas S ⁇ which is supplied through the conduit 16 in an amount of 5-10 kg (A per ton pulp.
  • the gas low through the lower portion 9 of the vessel 1 can be controlled.
  • the fan 15 3 thus, shall ensure a gradient in the downward flow rate between gas and pulp, in such a manner, that the gas speed shall exceed the pulp speed through this portion of the vessel 1.
  • the speed gradient shall be sufficiently great to cause such a pressure drop over the pulp bed in the lower vessel portion 9, that a good gas flow distribution in the entire pulp bed is obtained.
  • the pulp is discharged from the bottom of the vessel 1 by means of the rotary scraping device 19 to the surr ⁇ ounding tank 6.
  • the pulp is there diluted to low con ⁇ centration, preferably 3-5% t by means of the dilution nozzles 20, which at the same time cause the pulp to rotate along the screw-shaped passageway to the outlet 7.
  • the flow through the outlet is controlled so that a liquid level is maintained in the tank 6 for ensuring a gas-tight discharge.
  • the main part of the gas, which has not reacted with the pulp, goes off in the tank 6.
  • This gas is discharged through the conduit 14 via the space 17, which is so dimensioned that pulp and liquid are not taken along with the gas flow.
  • the processed pulp is thereafter pumped to continued processing in subsequent process steps.
  • An after- reaction however, may possibly be required, which takes place in the separate vessel 21, through which the pulp with the remaining gas content is passed continuously, being given the stay-time required for completing the reaction.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)

Abstract

Un appareil pour le traitement continu de pâte de cellulose à l'aide d'une substance chimique d'activation en phase gazeuse, de préférence le dioxyde d'azote, et un gaz contenant de l'oxygène. L'appareil consiste en un récipient imperméable au gaz (1) muni d'un dispositif d'alimentation imperméable au gaz (2) au sommet et un dispositif de sortie imperméable au gaz (5) à la base. Un conduit (13) pour la fourniture du dioxyde d'azote est relié au dessus dudit récipient qui est divisé en une partie supérieure (8) et une partie inférieure (9). Un conduit (14) muni d'un ventilateur (15) pour le recyclage du gaz en provenance du dispositif de décharge (5) est relié à la transition entre la partie supérieure (8) et la partie inférieure (9), là où le ventilateur est susceptible de créer un gradient dans l'écoulement vers le bas entre le gaz et la pâte de cellulose. Un conduit (16) d'alimentation d'oxygène sous forme de gaz est relié audit conduit de recyclage.
PCT/SE1989/000650 1988-11-25 1989-11-13 Appareil pour le traitement continu de pâte de cellulose WO1990006395A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
NO912008A NO912008D0 (no) 1988-11-25 1991-05-24 Apparat for kontinuerlig behandling av masse.
FI912522A FI912522A0 (fi) 1988-11-25 1991-05-24 Anordning foer kontinuerlig tillverkning av fibermassa.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8804260-1 1988-11-25
SE8804260A SE462567B (sv) 1988-11-25 1988-11-25 Anordning foer kontinuerlig behandling av cellulosamassa med en aktiveringskemikalie

Publications (1)

Publication Number Publication Date
WO1990006395A1 true WO1990006395A1 (fr) 1990-06-14

Family

ID=20374061

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/SE1989/000650 WO1990006395A1 (fr) 1988-11-25 1989-11-13 Appareil pour le traitement continu de pâte de cellulose

Country Status (8)

Country Link
EP (1) EP0445144A1 (fr)
JP (1) JPH04501890A (fr)
AU (1) AU4520389A (fr)
CA (1) CA2003769A1 (fr)
FI (1) FI912522A0 (fr)
NZ (1) NZ231501A (fr)
SE (1) SE462567B (fr)
WO (1) WO1990006395A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475930A1 (fr) * 1990-08-28 1992-03-18 Kamyr, Inc. Séparation et/ou mélange par centrifugation avec une aspersion gazeuse
WO1996022418A1 (fr) * 1995-01-16 1996-07-25 Grudinin, Alexandr Vladimirovich Procede de traitement d'un materiau fibreux a l'aide d'un reactif chimique et dispositif de traitement

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964962A (en) * 1974-02-25 1976-06-22 Ingersoll-Rand Company Gaseous reaction apparatus and processes including a peripheral gas receiving chamber and a gas recirculation conduit
US4762591A (en) * 1983-01-26 1988-08-09 Mo Och Domsjo Aktiebolag Apparatus for reacting lignocellulosic material with a gas phase comprising a nitrogen oxide and oxygen under controlled gas pressure

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3964962A (en) * 1974-02-25 1976-06-22 Ingersoll-Rand Company Gaseous reaction apparatus and processes including a peripheral gas receiving chamber and a gas recirculation conduit
US4762591A (en) * 1983-01-26 1988-08-09 Mo Och Domsjo Aktiebolag Apparatus for reacting lignocellulosic material with a gas phase comprising a nitrogen oxide and oxygen under controlled gas pressure

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0475930A1 (fr) * 1990-08-28 1992-03-18 Kamyr, Inc. Séparation et/ou mélange par centrifugation avec une aspersion gazeuse
AU638338B2 (en) * 1990-08-28 1993-06-24 Kamyr Inc. Gas sparged centrifugal separation and/or mixing
US5405497A (en) * 1990-08-28 1995-04-11 Kamyr, Inc. Method of chemically reacting a liquid with a gas in a vortex
WO1996022418A1 (fr) * 1995-01-16 1996-07-25 Grudinin, Alexandr Vladimirovich Procede de traitement d'un materiau fibreux a l'aide d'un reactif chimique et dispositif de traitement
US5932067A (en) * 1995-01-16 1999-08-03 Vitaly Valerievich Pukanov Method and apparatus for processing a fibrous mass in a spiral shaped flow-typed tube cell

Also Published As

Publication number Publication date
SE8804260D0 (sv) 1988-11-25
CA2003769A1 (fr) 1990-05-25
SE462567B (sv) 1990-07-16
JPH04501890A (ja) 1992-04-02
FI912522A0 (fi) 1991-05-24
EP0445144A1 (fr) 1991-09-11
AU4520389A (en) 1990-06-26
NZ231501A (en) 1991-12-23

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