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EP0308314A1 - Process for the ozone treatment of lignocellulosic materials, in particular paper pulps, and reactor for carrying out this process - Google Patents

Process for the ozone treatment of lignocellulosic materials, in particular paper pulps, and reactor for carrying out this process Download PDF

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Publication number
EP0308314A1
EP0308314A1 EP88402296A EP88402296A EP0308314A1 EP 0308314 A1 EP0308314 A1 EP 0308314A1 EP 88402296 A EP88402296 A EP 88402296A EP 88402296 A EP88402296 A EP 88402296A EP 0308314 A1 EP0308314 A1 EP 0308314A1
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Prior art keywords
treated
ozone
reactor
reaction
enclosure
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EP88402296A
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German (de)
French (fr)
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EP0308314B1 (en
Inventor
Christian Coste
Pierre Jan
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Suez International SAS
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Degremont SA
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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
    • 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
    • D21C9/147—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications
    • D21C9/153—Bleaching ; Apparatus therefor with oxygen or its allotropic modifications with ozone

Definitions

  • the present invention relates to the treatment with ozone of lignocellulosic material and in particular of paper pulp.
  • ozone has an action on lignocellular materials in general and in particular on lignin. This action, which leads to chemical degradation resulting in elimination of the wood structure, has been used for bleaching, in particular pulp. It has been found that the treatment of paper pulps with ozone, applied during the refining phase, leads to a reduction in the overall energy necessary for this refining, at the cost, however, of an increase in the duration of this phase, therefore treatment, due to the slow reaction of the ozone on the dough.
  • ozonation has not made evident the favorable influence of ozone on the improvement of the paper qualities, in particular of the mechanical qualities of certain pulps, like that of so-called “thermomechanical” “mechanical”, “chemico-thermo-mechanical” dough, that is to say dough obtained by grating logs in a humid environment on grinding wheels, or by shredding chips previously softened with water or steam, with a light chemical and / or heat treatment.
  • FR-A 2 474 550 discloses a process for bleaching cellulosic pulp with ozone, which consists in treating a pulp previously brought to a desired hygrometric state so as to ensure that the ozonation treatment runs smoothly. Such a process is not entirely satisfactory, in particular as regards the mechanical properties of the material obtained.
  • the present invention proposes to provide a method of treatment with ozone, improved compared to the prior art and providing unexpected results which will be reported below.
  • this invention relates to a process for the treatment with ozone of lignocellulosic material, in particular paper pulp, according to which the material is brought beforehand to the desired hygrometric state so that the ozone reaction can take place in optimal conditions characterized in that the material, brought to the desired hygrometric state is reduced to a state of sufficient division to ensure between the carrier gas of the ozone and the fibrous solid, an interface of maximum value and in that then said material is subjected to ozonation by means of a carrier gas in which the ozone concentration is between 4 and 10% by mass relative to said carrier gas.
  • the material is treated before ozonation by any means whatsoever, so that its dryness is in a range between 20 and 50%.
  • the improvement of the paper qualities of the finished products obtained after treatment with ozone according to the process according to the invention also makes it possible to increase the productivity by a significant gain on the speed of manufacture of paper or cardboard, as well as by an increase. speeds of machines ensuring processing or final use, printing, for example.
  • the Applicant has also been able to demonstrate that, when the ozone treatment is carried out in accordance with the process according to the invention, the compounds with an aromatic structure which constitute the lignin framework are transformed into by-products which no longer have the benzene function.
  • This transformation has the advantage of limiting the weight loss due to the disappearance of the lignin to a minimal value and of retaining an excellent yield by weight of the lignocellulosic materials thus treated.
  • a manufacture of paper pulp according to a conventional chemical process makes it possible to obtain an overall yield of the order of 45 to 60% while a manufacture of pulp according to a process in accordance with the invention provides a weight yield of about 90% with equal levels of ozone 5 0/0 in mass compared to the material considered dry. Thanks to the process according to the invention, it is possible to obtain paper pulps whose paper qualities, such as for example, the length of break or the burst index are close to those of pulps obtained by conventional chemical transformation with the advantage of a clearly favorable weight yield.
  • the process according to the invention can be implemented by means of a reactor which has been described below solely by way of nonlimiting example, a possible embodiment, this description being given with reference to the appended drawing which shows schematically an installation comprising such a reactor.
  • Ozone is produced from oxygen carried by a pipe (1) and introduced into a generator (2) electrically supplied at medium frequency and cooled with chilled water brought by a pipe (3) and evacuated by a pipe ( 4).
  • the characteristics of this generator are chosen so as to obtain high ozone concentrations of between 70 and 140 g / Nm3.
  • the high concentration ozone gas thus produced is sent via a pipe (5) to a reactor (6) constituted by an elongated enclosure slightly inclined on the horizontal in which the flow and mixing of the cellulosic material to be ozonated is ensured. by a simple screw system (7) like an Archimedes screw provided with a cleaning device (not shown) and ensuring a propulsion and a flow of the lignocellulosic material to be treated and favoring a continuous renewal of the material interface- gas.
  • the reactions of ozone on the lignocellulosic structures passing through a maximum depending on the height of the layer of material to be treated, the assembly is designed and adjusted so that the height of the layer of material being in the reactor remains weak and is advantageously around ten cm.
  • the ozonated gas is injected at several points (8) distributed over the length of the reactor by means of orifices provided in the part of the pipeline (5) located inside the reactor so as to ensure a radial flow of interest over the entire volume. reactive.
  • a conventional flow control device (not shown) allows this flow to be adjusted in each of the reaction zones defined by the injection points.
  • the introduction of lignocellulosic material into the reactor (6) takes place using a hopper (9) supplying a screw (10) of the plug type ensuring both the regulation of the rate of introduction of the material in the reaction vessel and the seal necessary to prevent leakage of ozonated gas to the atmosphere.
  • the extraction of the lignocellulosic material treated at the outlet of the reactor is carried out by means of a screw (11) also of the plug type ensuring both the regulation of the flow rate of the extracted product and the tightness necessary to prevent leakage of ozonated gas to the atmosphere.
  • the lignocellulosic material is brought, before its introduction into the ozonization reactor, by any means or any device suitable for a state of controlled dryness between 30 and 45% humidity.
  • the residence time of the lignocellulosic material necessary for obtaining the desired paper qualities is adjusted by adjusting the speed of rotation of the screw (7) ensuring the progression of the material in the treatment enclosure.
  • the small quantity of ozone which has not reacted with the lignocellulosic material is extracted from the reactor by suction and directed by a pipe (12) to a unit (14) for ozone destruction by thermal means.
  • the breaking length represents the length in meters of a strip of uniform width thickness supposed to be suspended by one of its ends and breaking under the effect of its own weight.
  • the burst index is an index reflecting the force to be applied, by means of a device capable of exerting hydrostatic pressure on a paper sample to cause it to burst.

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

Abstract

Process for the ozone treatment of lignocellulosic material, especially of paper pulp, according to which the material is brought to the desired moisture content beforehand in order that the ozonation reaction may take place under optimum conditions, characterised in that the material brought to the desired moisture content is reduced to a sufficient state of division to ensure an interface of maximum value between the ozone-carrier gas and the fibrous solid and in that the said material is then subjected to ozonation by means of a carrier gas in which the ozone concentration is between 4 and 10% on a mass basis in relation to the said carrier gas. <IMAGE>

Description

La présente invention concerne le traitement par l'ozone de matériau ligno-cellulosique et notamment de la pâte à papier.The present invention relates to the treatment with ozone of lignocellulosic material and in particular of paper pulp.

Il est connu que l'ozone a une action sur les matériaux ligno-cellusosiques en général et en particulier sur la lignine. Cette action, qui conduit à une dégradation chimique se traduisant par une élimination de la structure ligneuse, a été utilisée pour le blanchiment, en particulier de pâtes à papier. On a constaté que le traitement des pâtes à papier par l'ozone, appliqué pendant la phase de raffinage, entrainait une réduction de l'énergie globale nécs- saire à ce raffinage au prix cependant d'une augmentation de la durée de cette phase, donc du traitement, en raison de la lenteur de la réaction de l'ozone sur la pâte.It is known that ozone has an action on lignocellular materials in general and in particular on lignin. This action, which leads to chemical degradation resulting in elimination of the wood structure, has been used for bleaching, in particular pulp. It has been found that the treatment of paper pulps with ozone, applied during the refining phase, leads to a reduction in the overall energy necessary for this refining, at the cost, however, of an increase in the duration of this phase, therefore treatment, due to the slow reaction of the ozone on the dough.

Par ailleurs, l'ozonation, telle qu'elle a été mise en oeuvre jusqu'à mainternant n'a pas rendu évidente l'influence favorable de l'ozone sur l'amélioration des qualités papetières, notamment des qualités mécaniques de certaines pâtes, comme celles des pâtes dites "thermomécaniques" "mécaniques", "chimico-thermo-mécaniques", c'est-à-dire des pâtes obtenues par râpage de rondins en milieu humide sur des meules, ou par déchiquetage de copeaux préalablement ramollis à l'eau ou à la vapeur, avec un léger traitement chimique et/ou thermique.Furthermore, ozonation, as it has been implemented until now, has not made evident the favorable influence of ozone on the improvement of the paper qualities, in particular of the mechanical qualities of certain pulps, like that of so-called "thermomechanical" "mechanical", "chemico-thermo-mechanical" dough, that is to say dough obtained by grating logs in a humid environment on grinding wheels, or by shredding chips previously softened with water or steam, with a light chemical and / or heat treatment.

On connait FR-A 2 474 550 un procédé de blanchiment à l'ozone de pâte cellulosique qui consiste à traiter une pâte préalablement amenée à un état hygrométrique voulu de manière à assurer un bon déroulement du traitement d'ozonation. Un tel procédé ne donne pas entière satisfaction notamment en ce qui concerne les propriétés mécaniques du matériau obtenu.FR-A 2 474 550 discloses a process for bleaching cellulosic pulp with ozone, which consists in treating a pulp previously brought to a desired hygrometric state so as to ensure that the ozonation treatment runs smoothly. Such a process is not entirely satisfactory, in particular as regards the mechanical properties of the material obtained.

La présente invention se propose d'apporter un procédé de traitement par l'ozone, amélioré par rapport à l'état antérieur de la technique et procurant des résultats inattendus dont il sera fait état ci-après.The present invention proposes to provide a method of treatment with ozone, improved compared to the prior art and providing unexpected results which will be reported below.

En conséquence, cette invention concerne un procédé de traitement par l'ozone de matériau ligno-cellulosique notamment de pâte à papier selon lequel le matériau est préalablement amené à l'état hygrométrique voulu pour que la réaction d'ozona- tion puisse se dérouler dans des conditions optimales caractérisé en ce que le matériau , amené à l'état hygrométrique voulu est réduit à un état de division suffisante pour assurer entre le gaz vecteur de l'ozone et le solide fibreux, une interface de valeur maximale et en ce qu'ensuite ledit matériau est soumis à l'ozonation au moyen d'un gaz vecteur dans lequel la concentration en ozone se situe entre 4 et 10 % en masse par rapport audit gaz vecteur.Consequently, this invention relates to a process for the treatment with ozone of lignocellulosic material, in particular paper pulp, according to which the material is brought beforehand to the desired hygrometric state so that the ozone reaction can take place in optimal conditions characterized in that the material, brought to the desired hygrometric state is reduced to a state of sufficient division to ensure between the carrier gas of the ozone and the fibrous solid, an interface of maximum value and in that then said material is subjected to ozonation by means of a carrier gas in which the ozone concentration is between 4 and 10% by mass relative to said carrier gas.

La demanderesse a constaté qu'en opérant conformément au procédé défini ci-dessus, on obtenait des résultats surprenants en ce qui concerne non seulement la diminution de la durée de réaction mais également et surtout des améliorations significatives des qualités mécaniques du matériau obtenu, en particulier de la longueur de rupture et de l'indice d'éclatement des pâtes à papier, en particulier des pâtes du type chimico-thermo-mécanique, mécanique, thermo-mécanique.The Applicant has found that by operating in accordance with the process defined above, surprising results were obtained as regards not only the reduction in the reaction time but also and above all significant improvements in the mechanical qualities of the material obtained, in particular the breaking length and the burst index of the paper pulps, in particular of the chemical-thermo-mechanical, mechanical, thermo-mechanical type.

Conformément à l'invention, le matériau est traité avant l'ozonation par tout moyen quelconque, de façon à ce que sa siccité se situe dans une plage comprise entr 20 et 50 %.According to the invention, the material is treated before ozonation by any means whatsoever, so that its dryness is in a range between 20 and 50%.

Avantageusement suivant encore une autre caractéristique de l'invention, la quantité d'ozone introduite pour assurer la réaction se situe entre 2 et 8 % en masse par rapport à la matière sèche. Le procédé suivant l'invention présente en particulier les avantages suivants :

  • - les temps de réaction conduisant à l'obtention d'améliorations significatives des qualités des matériaux traités sont de 10 à 30 fois plus faibles que ceux réalisés avec les procédés connus, ce qui permet d'obtenir les réactions voulues avec des durées allant de quelques secondes à une centaine de secondes .
  • - les caractéristiques mécaniques du matériau traité (longueur de rupture, résistance à l'éclatement) présentent des gains pouvant atteindre 50 à 60 % par rapport aux valeurs initiales, en fonction des taux d'ozones appliqués. Ces gains considérables permettent d'améliorer les qualités du produit fini, papier ou carton de toute nature, et permettent de la même façon de réduire substantiellement les quantités des pâtes chimiques entrant dans la composition finale des mélanges destinés à la fabrication de papier présentant des qualités particulières.
Advantageously according to yet another characteristic of the invention, the amount of ozone introduced to ensure the reaction is between 2 and 8% by mass relative to the dry matter. The process according to the invention has in particular the following advantages:
  • - the reaction times leading to obtaining significant improvements in the qualities of the treated materials are 10 to 30 times lower than those achieved with known methods, which makes it possible to obtain the desired reactions with durations ranging from a few seconds to a hundred seconds.
  • - the mechanical characteristics of the treated material (rupture length, bursting strength) show gains of up to 50 to 60% compared to the initial values, depending on the ozone levels applied. These considerable gains make it possible to improve the qualities of the finished product, paper or cardboard of all kinds, and in the same way make it possible to substantially reduce the quantities of chemical pulps entering into the final composition of the mixtures intended for the manufacture of paper having qualities particular.

L'amélioration des qualités papetières des produits finis obtenue après traitement par l'ozone selon le procédé suivant l'invention, permet également d'augmenter la productivité par un gain sensible sur la vitesse de fabrication des papiers ou cartons , ainsi que par une augmentation des vitesses des machines assurant la transformation ou l'utilisation finale, imprimerie, par exemple.The improvement of the paper qualities of the finished products obtained after treatment with ozone according to the process according to the invention also makes it possible to increase the productivity by a significant gain on the speed of manufacture of paper or cardboard, as well as by an increase. speeds of machines ensuring processing or final use, printing, for example.

La demanderesse a également pu mettre en évidence que, lorsque le traitement par l'ozone s'effectue conformément au procédé suivant l'invention, les composés à structure aromatique qui constituent l'ossature de la lignine sont transformés en sous-produits ne présentant plus la fonction benzénique.The Applicant has also been able to demonstrate that, when the ozone treatment is carried out in accordance with the process according to the invention, the compounds with an aromatic structure which constitute the lignin framework are transformed into by-products which no longer have the benzene function.

Cette transformation a pour avantage de limiter la perte de poids due à la disparition de la lignine à une valeur minime et de conserver un excellent rendement en poids des matériaux ligno-cellulosiques ainsi traités. A titre d'exemple non limitatif, une fabrication de pâte à papier selon un procédé chimique classique permet d'obtenir un rendement global de l'ordre de 45 à 60 % alors qu'une fabrication de pâte selon un procédé conforme à l'invention permet d'obtenir un rendement en poids de l'ordre de 90 % avec un taux d'ozone égal à 5 0/0 en masse par rapport au matériau considéré sec. Grâce au procédé suivant l'invention, il est possible d'obtenir des pâtes à papier dont les qualités papetières, comme par exemple, la longueur de rupture ou l'indice d'éclatement sont voisines de celles des pâtes obtenues par transformation chimique classique avec l'avantage d'un rendement en poids nettement favorable. Le procédé suivant l'invention peut être mis en oeuvre au moyen d'un réacteur dont on a décrit ci-après uniquement à titre d'exemple non limitatif, une forme possible de réalisation, cette description étant faite en référence au dessin annexé qui montre schématiquement une installation comportant un tel réacteur.This transformation has the advantage of limiting the weight loss due to the disappearance of the lignin to a minimal value and of retaining an excellent yield by weight of the lignocellulosic materials thus treated. By way of nonlimiting example, a manufacture of paper pulp according to a conventional chemical process makes it possible to obtain an overall yield of the order of 45 to 60% while a manufacture of pulp according to a process in accordance with the invention provides a weight yield of about 90% with equal levels of ozone 5 0/0 in mass compared to the material considered dry. Thanks to the process according to the invention, it is possible to obtain paper pulps whose paper qualities, such as for example, the length of break or the burst index are close to those of pulps obtained by conventional chemical transformation with the advantage of a clearly favorable weight yield. The process according to the invention can be implemented by means of a reactor which has been described below solely by way of nonlimiting example, a possible embodiment, this description being given with reference to the appended drawing which shows schematically an installation comprising such a reactor.

L'ozone est produit à partir d'oxygène véhiculé par une canalisation (1) et introduit dans un générateur (2) alimenté électriquement en moyenne fréquence et refroidi à l'eau réfrigérfée amenée par une canalisation (3) et évacuée par une canalisation (4). Les caractéristiques de ce générateur sont choisies de façon à obtenir de fortes concentrations en ozone comprises entre 70 et 140 g/Nm3.Ozone is produced from oxygen carried by a pipe (1) and introduced into a generator (2) electrically supplied at medium frequency and cooled with chilled water brought by a pipe (3) and evacuated by a pipe ( 4). The characteristics of this generator are chosen so as to obtain high ozone concentrations of between 70 and 140 g / Nm3.

Le gaz ozoné à forte concentration ainsi produit est envoyé par une canalisation (5) dans un réacteur (6) constitué par une enceinte de forme allongée légèrement inclinée sur l'horizontale dans laquelle l'écoulement et le brassage du matériau cellulosique à ozoner sont assurés par un système de vis simple (7) genre vis d'Archimède muni d'un dispositif de débourrage (non représenté) et assurant une propulsion et un écoulement du matériau ligno-cellulosique à traiter et favorisant un renouvellement continu de l'interface matériau-gaz. Les réactions de l'ozone sur les structures ligno-cellulosiques passant par un maximum en fonction de la hauteur de la couche de matériau à traiter, l'ensemble est conçu et réglé de façon à ce que la hauteur de la couche de matériau se trouvant dans le réacteur reste faible et se situe avantageusement aux environs d'une dizaine de cm.The high concentration ozone gas thus produced is sent via a pipe (5) to a reactor (6) constituted by an elongated enclosure slightly inclined on the horizontal in which the flow and mixing of the cellulosic material to be ozonated is ensured. by a simple screw system (7) like an Archimedes screw provided with a cleaning device (not shown) and ensuring a propulsion and a flow of the lignocellulosic material to be treated and favoring a continuous renewal of the material interface- gas. The reactions of ozone on the lignocellulosic structures passing through a maximum depending on the height of the layer of material to be treated, the assembly is designed and adjusted so that the height of the layer of material being in the reactor remains weak and is advantageously around ten cm.

Le gaz ozoné est injecté en plusieurs points (8) répartis sur la longueur du réacteur grâce à des orifices ménagés dans la partie de la canalisation (5) située à l'intérieur du réacteur de manière à assurer un flux radial intéressant la totalité du volume réactionnel. Un dispositif de régulation de débit classique (non représenté) permet d'ajuster ce débit dans chacune des zones réactionnelles définies par les points d'injection.The ozonated gas is injected at several points (8) distributed over the length of the reactor by means of orifices provided in the part of the pipeline (5) located inside the reactor so as to ensure a radial flow of interest over the entire volume. reactive. A conventional flow control device (not shown) allows this flow to be adjusted in each of the reaction zones defined by the injection points.

L'introduction du matériau ligno-cellulosique dans le réacteur (6) s'opère à l'aide d'une trémie (9) alimentant une vis (10) de type bouchon assurant à la fois la régulation du débit d'introduction du matériau dans l'enceinte réactionnelle et l'étanchéité nécessaire pour éviter les fuites de gaz ozoné à l'atmosphère.The introduction of lignocellulosic material into the reactor (6) takes place using a hopper (9) supplying a screw (10) of the plug type ensuring both the regulation of the rate of introduction of the material in the reaction vessel and the seal necessary to prevent leakage of ozonated gas to the atmosphere.

De la même façon, l'extraction du matériau ligno-cellulosique traité en sortie de réacteur est réalisée par l'intermédiaire d'une vis (11) également de type bouchon assurant à la fois la régulation du débit du produit extrait et l'étanchéité nécessaire pour éviter les fuites de gaz ozoné à l'atmosphère.In the same way, the extraction of the lignocellulosic material treated at the outlet of the reactor is carried out by means of a screw (11) also of the plug type ensuring both the regulation of the flow rate of the extracted product and the tightness necessary to prevent leakage of ozonated gas to the atmosphere.

Le matériau ligno-cellulosiqu est amené, avant son introduction dans le réacteur d'ozonation, par tout moyen ou dispositif quelconque convenable à un état de siccité contrôlée se situant entre 30 et 45 % d'humidité. Le temps de séjour du matériau ligno-cellulosique nécessaire à l'obtention des qualités papetières souhaitées est ajusté par réglage de la vitesse de rotation de la vis (7) assurant la progression du matériau dans l'enceinte de traitement.The lignocellulosic material is brought, before its introduction into the ozonization reactor, by any means or any device suitable for a state of controlled dryness between 30 and 45% humidity. The residence time of the lignocellulosic material necessary for obtaining the desired paper qualities is adjusted by adjusting the speed of rotation of the screw (7) ensuring the progression of the material in the treatment enclosure.

La faible quantité d'ozone n'ayant pas réagi avec le matériau ligno-cellulosique est extraite du réacteur par aspiration et dirigée par une canalisation (12) vers une unité (14) de destruction d'ozone par voie thermique.The small quantity of ozone which has not reacted with the lignocellulosic material is extracted from the reactor by suction and directed by a pipe (12) to a unit (14) for ozone destruction by thermal means.

La réaction de l'ozone sur les structures ligneuses en phase semi-humide (siccité du matériau comprise entre 20 et 50 % , conformément à l'invention) étant, comme l'a constaté la demanderesse, de type très fortement exothermique un circuit de refroidissement (13) est installé dans l'enveloppe du réacteur de façon à contrôler et à limiter l'élévation de température dans l'enceinte réactionnelle. Dans ces conditions, la température reste inférieure à 50 ° C en tous les points du réacteur ce qui limite la réaction d'auto-décomposition de l'ozone et permet d'avoir une consommation d'ozone ajustée à la seule stoechiométrie de la réaction de transformation de la lignine.The reaction of ozone on woody structures in the semi-humid phase (dryness of the material between 20 and 50%, in accordance with the invention) being, as the applicant has observed, of a very strongly exothermic type a circuit of cooling (13) is installed in the reactor casing so as to control and limit the rise in temperature in the reaction enclosure. Under these conditions, the temperature remains below 50 ° C. at all points of the reactor, which limits the self-decomposition reaction of the ozone and makes it possible to have an ozone consumption adjusted to the only stoichiometry of the reaction. lignin processing.

Au moyen d'un réacteur tel que celui qui vient d'être décrit on a obtenu les résultats consignés dans le tableau suivant :

Figure imgb0001
By means of a reactor such as that which has just been described, the results given in the following table have been obtained:
Figure imgb0001

La longueur de rupture représente la longueur en mètre d'une bande d'épaisseur largeur uniformes supposée suspendue par une de ses extrémités et se rompant sous l'effet de son propre poids. L'indice d'éclatement est un indice rendant compte de l'effort devant être appliqué, par l'intermédiaire d'un dispositif susceptible d'exercer une pression hydrostatique à un échantillon de papier pour provoquer son éclatement Ce tableau montre de façon éloquente les avantages que présente l'invention notamment en ce qui concerne la durée de la réaction (temps de contact) et les caractéristiques papetières du produit traité.The breaking length represents the length in meters of a strip of uniform width thickness supposed to be suspended by one of its ends and breaking under the effect of its own weight. The burst index is an index reflecting the force to be applied, by means of a device capable of exerting hydrostatic pressure on a paper sample to cause it to burst. This table eloquently shows the advantages of the invention, in particular with regard to the duration of the reaction (contact time) and the paper characteristics of the product treated.

Cependant, le type de réacteur décrit et représenté n'est pas le seul qui puisse être utilisé.However, the type of reactor described and shown is not the only one that can be used.

On peut également utiliser pour la mise en oeuvre du procédé suivant l'invention des réacteurs de conceptions diverses, et telles que définies ci-après.

  • - Réacteur de type tunnel à lit mobile dans lequel le matériau à traiter en couche de faible épaisseur est transporté mécaniquement et traversé par le gaz de traitement dont le flux est réparti sur toute la surface du lit pour homogénéiser l'attaque du matériau par le gaz de traitement;
  • - Réacteur dont l'enceinte en forme de corps de révolution avantageusement cylindrique et animée d'un mouvement de rotation autour de son axe, l'enceinte étant munie au moins d'un dispositif provoquant une turbulence de manière à perturber l'écoulement dans l'enceinte du matériau à traiter ;
  • - Réacteur dont l'enceinte est verticale et comporte une pluralité de soles inclinées pour permettre un écoulement gravitaire du matériau solide avec utilisation de bras racleurs pour réaliser un brassage mécanique, le gaz ozoné circulant dans le même sens ou à contre-courant de l'écoulement du matériau à traiter.
It is also possible to use, for implementing the process according to the invention, reactors of various designs, and as defined below.
  • - Tunnel type reactor with moving bed in which the material to be treated in a thin layer is mechanically transported and traversed by the treatment gas, the flux of which is distributed over the entire surface of the bed to homogenize the attack of the material by the gas treatment;
  • - Reactor whose enclosure in the form of an advantageously cylindrical body of revolution and driven in a rotational movement about its axis, the enclosure being provided with at least one device causing turbulence so as to disturb the flow in the 'enclosure of the material to be treated;
  • - Reactor whose enclosure is vertical and includes a plurality of inclined soles to allow gravity flow of the solid material with the use of scraper arms to effect mechanical mixing, the ozonated gas circulating in the same direction or against the current of the flow of the material to be treated.

II doit être bien entendu que cette liste a uniquement valeur d'exemple et n'est en aucune façon limitative.It should be understood that this list is only an example and is in no way limiting.

Claims (10)

1 - Procédé de traitement par l'ozone de matériau ligno-cellulosique, notamment de pâte à papier selon lequel le matériau est préalablement amené à l'état hygrométrique voulu pour que la réaction d'ozonation puisse se dérouler dans des conditions optimales caractérisé en ce que le matériau amené à l'état hygrométrique voulu est réduit à un état de division suffisante pour assurer entre le gaz vecteur de l'ozone et le solide fibeux, une interface de valeur maximale et en ce qu'ensuite ledit matériau est soumis à l'ozonation au moyen d'un gaz vecteur dans lequel la concentration en ozone se situe entre 4 et 10 % en masse par rapport audit gaz vecteur.1 - Method of treatment with ozone of lignocellulosic material, in particular of paper pulp according to which the material is brought beforehand to the desired hygrometric state so that the ozonization reaction can take place under optimal conditions characterized in that that the material brought to the desired hygrometric state is reduced to a state of sufficient division to ensure between the carrier gas of the ozone and the fibrous solid, an interface of maximum value and in that said material is subjected to the ozonation by means of a carrier gas in which the ozone concentration is between 4 and 10% by mass relative to said carrier gas. 2 - Procédé suivant la revendication 1, caractérisé en ce que le matériau présente une siccité se situant avantageusement dans une plage comprise entre 20 et 50 0/0.2 - Process according to Claim 1, characterized in that the material has a solids content is advantageously in a range between 20 and 50 0/0. 3 - Procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce que la quantité d'ozone introduite pour assurer la réaction se situe entre 2 et 8 % en masse par rapport à la matière sèche.3 - Process according to any one of the preceding claims, characterized in that the amount of ozone introduced to ensure the reaction is between 2 and 8% by mass relative to the dry matter. 4 - Réacteur pour la mise en oeuvre du procédé suivant l'une quelconque des revendications précédentes, caractérisé en ce qu'il consiste en une enceinte (6) de préférence légèrement inclinée sur l'horizontale à laquelle sont amenés le gaz de traitement et le matériau à traiter et qui comporte des moyens, tels que vis d'Archimède (7) conçus et régies de façon à maintenir le matériau à traiter en couche mince et à assurer un renouvellement continu de l'interface : matériau - gaz de traitement.4 - Reactor for implementing the method according to any one of the preceding claims, characterized in that it consists of an enclosure (6) preferably slightly inclined on the horizontal to which the treatment gas and the material to be treated and which comprises means, such as Archimedes screw (7) designed and governed so as to maintain the material to be treated in a thin layer and to ensure continuous renewal of the interface: material - treatment gas. 5 - Réacteur suivant la revendication 4,caractérisé en ce que la couche de matériau à traiter se trouve dans le réacteur sous une épaisseur d'environ une dizaine de cm.5 - Reactor according to claim 4, characterized in that the layer of material to be treated is located in the reactor at a thickness of about ten cm. 6 - Réacteur suivant l'une quelconque des revendications 4 et 5 caractérisé en ce qu'il est refroidi pour contrôler l'exothermicité de la réaction.6 - Reactor according to any one of Claims 4 and 5 characterized in that it is cooled to control the exothermicity of the reaction. 7 - Réacteur suivant l'une quelconque des revendications 4 à 6 caractérisé en ce qu'il comporte, pour l'introduction du matériau et son extraction après réaction des dispositifs tels que vis-bouchon (10-11) assurant à la fois la régulation des débits de matériau à traiter et de gaz ozoné et de traitement et l'étanchéité de l'enceinte où a lieu la réaction.7 - Reactor according to any one of claims 4 to 6 characterized in that it comprises, for the introduction of the material and its extraction after reaction of devices such as screw-cap (10-11) ensuring both the regulation flow rates of material to be treated and ozonated and treatment gas and the tightness of the enclosure where the reaction takes place. 8 - Réacteur suivant la revendication 4 caractérisé en ce qu'il est de type tunnel à lit mobile dans lequel le matériau à traiter est transporté mécaniquement sous forme d'une couche de faible épaisseur et traversé par le gaz de traitement dont le flux est réparti sur toute la surface du lit pour homogénéiser l'attaque du matériau à traiter par le gaz ozoné de traitement.8 - Reactor according to claim 4 characterized in that it is of the moving bed tunnel type in which the material to be treated is mechanically transported in the form of a thin layer and traversed by the treatment gas whose flow is distributed over the entire surface of the bed to homogenize the attack of the material to be treated by the ozonized treatment gas. 9 - Réacteur suivant la revendication 4 caractérisé en ce qu'il comporte une enceinte en forme de corps de révolution avantageusement cylindrique et animé d'un mouvement de rotation autour de son axe, l'enceinte étant munie d'un dispositif provoquant une turbulence dans l'écoulement du solide de façon à perturber cet écoulement.9 - Reactor according to claim 4 characterized in that it comprises an enclosure in the form of an advantageously cylindrical body of revolution and driven in a rotational movement about its axis, the enclosure being provided with a device causing turbulence in the flow of the solid so as to disturb this flow. 10 - Réacteur suivant la revendication 4 caractérisé en ce que l'enceinte est verticale et comporte une pluralité de soles inclinées pour permettre un écoulement gravitaire du matériau solide, des bras racleurs étant prévus pour réaliser un brassage mécanique et le gaz ozoné de traitement circulant dans le même sens ou à contre-courant de l'écoulement du matériau à traiter.10 - Reactor according to claim 4 characterized in that the enclosure is vertical and comprises a plurality of inclined sole plates to allow gravity flow of the solid material, scraper arms being provided for carrying out mechanical mixing and the ozonated treatment gas circulating in the same direction or against the flow of the material to be treated.
EP88402296A 1987-09-17 1988-09-12 Process for the ozone treatment of lignocellulosic materials, in particular paper pulps, and reactor for carrying out this process Expired - Lifetime EP0308314B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT88402296T ATE82340T1 (en) 1987-09-17 1988-09-12 PROCESS FOR THE OZONE TREATMENT OF LIGNOCELLULOSIC MATERIALS, ESPECIALLY PAPER PULP, AND REACTOR FOR CARRYING OUT THE PROCESS.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8712890 1987-09-17
FR8712890A FR2620744A1 (en) 1987-09-17 1987-09-17 PROCESS FOR THE OZONE TREATMENT OF LIGNO-CELLULOSIC MATERIALS, IN PARTICULAR PAPER PULP AND REACTOR FOR THE IMPLEMENTATION OF SAID METHOD

Publications (2)

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EP0308314A1 true EP0308314A1 (en) 1989-03-22
EP0308314B1 EP0308314B1 (en) 1992-11-11

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EP88402296A Expired - Lifetime EP0308314B1 (en) 1987-09-17 1988-09-12 Process for the ozone treatment of lignocellulosic materials, in particular paper pulps, and reactor for carrying out this process

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EP (1) EP0308314B1 (en)
JP (1) JP2731822B2 (en)
AT (1) ATE82340T1 (en)
BR (1) BR8804806A (en)
CA (1) CA1314664C (en)
DE (2) DE308314T1 (en)
ES (1) ES2035339T3 (en)
FI (1) FI93867C (en)
FR (1) FR2620744A1 (en)
NO (1) NO174781C (en)

Cited By (15)

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US5087326A (en) * 1991-02-20 1992-02-11 Union Camp Patent Holding, Inc. Rotating pulp bleaching reactor having inner and outer shells and lifting means on the interior surface of the inner shell
WO1992007999A1 (en) * 1990-10-26 1992-05-14 Union Camp Patent Holding, Inc. Pulp bleaching reactor and method
EP0492039A1 (en) * 1990-12-27 1992-07-01 Kamyr, Inc. Pneumatic reactor ozone bleaching of paper pulp
EP0492040A1 (en) * 1990-12-21 1992-07-01 Kamyr, Inc. Tumbling ozone reactor for paper pulp
US5174861A (en) * 1990-10-26 1992-12-29 Union Camp Patent Holdings, Inc. Method of bleaching high consistency pulp with ozone
US5211811A (en) * 1989-02-15 1993-05-18 Union Camp Patent Holding, Inc. Process for high consistency oxygen delignification of alkaline treated pulp followed by ozone delignification
US5296099A (en) * 1990-05-17 1994-03-22 Union Camp Holding, Inc. Environmentally improved process for bleaching lignocellulosic materials with oxygen, ozone and chlorine dioxide
EP0627029A1 (en) * 1992-01-15 1994-12-07 Union Camp Patent Holding, Inc. Pulp bleaching apparatus and method
US5409570A (en) * 1989-02-15 1995-04-25 Union Camp Patent Holding, Inc. Process for ozone bleaching of oxygen delignified pulp while conveying the pulp through a reaction zone
US5441603A (en) * 1990-05-17 1995-08-15 Union Camp Patent Holding, Inc. Method for chelation of pulp prior to ozone delignification
US5451296A (en) * 1991-05-24 1995-09-19 Union Camp Patent Holding, Inc. Two stage pulp bleaching reactor
US5520783A (en) * 1990-10-26 1996-05-28 Union Camp Patent Holding, Inc. Apparatus for bleaching high consistency pulp with ozone
USRE36033E (en) * 1989-08-16 1999-01-12 Maschinenfabrik Andritz Actiengesellschaft Process for the comminution of materials and plants for carrying out the process
US6174409B1 (en) 1997-09-19 2001-01-16 American Air Liquide Inc. Method to improve final bleached pulp strength properties by adjusting the CI02:03 ration within a single (D/Z) stage of the bleaching process
AP1537A (en) * 2000-07-06 2006-01-10 Servier Lab A crystalline form of perindopril tert-butylamine salt.

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US5188708A (en) 1989-02-15 1993-02-23 Union Camp Patent Holding, Inc. Process for high consistency oxygen delignification followed by ozone relignification
FI89516B (en) * 1989-05-10 1993-06-30 Ahlstroem Oy Foerfarande Foer blekning av cellulosamassa med Otson
US5164043A (en) 1990-05-17 1992-11-17 Union Camp Patent Holding, Inc. Environmentally improved process for bleaching lignocellulosic materials with ozone
US5411633A (en) * 1991-04-30 1995-05-02 Kamyr, Inc. Medium consistency pulp ozone bleaching
FI925558A (en) * 1992-04-22 1993-10-23 Ahlstroem Oy FOERFARANDE OCH ANORDNING FOER BLEKNING AV MASSA
US5387317A (en) * 1993-01-28 1995-02-07 The Mead Corporation Oxygen/ozone/peracetic aicd delignification and bleaching of cellulosic pulps
US5810973A (en) * 1993-09-21 1998-09-22 Beloit Technologies, Inc. Apparatus for producing small particles from high consistency wood pulp
US5554259A (en) 1993-10-01 1996-09-10 Union Camp Patent Holdings, Inc. Reduction of salt scale precipitation by control of process stream Ph and salt concentration
WO1996005365A1 (en) * 1994-08-11 1996-02-22 Beloit Technologies, Inc. Means for gas-sealingly conveying shredded pulp
US5944952A (en) * 1995-07-26 1999-08-31 Beloit Technologies, Inc. Method for bleaching high consistency pulp with a gaseous bleaching reagent
US6077396A (en) * 1997-05-16 2000-06-20 Lariviere; Christopher J. Apparatus for fluffing and contacting high consistancy wood pulp with a gaseous bleaching reagent
SE514416C2 (en) * 1999-06-10 2001-02-19 Valmet Fibertech Ab Method and system for gas-tight feed of pulp to an ozone bleaching reactor

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US2013115A (en) * 1931-09-21 1935-09-03 Thorne Carl Busch Process and apparatus for the refining of pulp
US2466633A (en) * 1948-05-26 1949-04-05 James M Daily Method of bleaching cellulosic pulp
FR1441787A (en) * 1965-04-30 1966-06-10 Progil Pulp bleaching process
FR2329794A1 (en) * 1975-10-31 1977-05-27 Myrens Verksted As METHOD AND APPARATUS FOR TREATING A FINALLY DIVIDED MATERIAL WITH A GAS
EP0030158A1 (en) * 1979-12-03 1981-06-10 The Black Clawson Company Apparatus and process for medium consistency oxygen delignification of pulp
FR2474550A1 (en) * 1980-01-24 1981-07-31 Scott Paper Co Two stage pulp bleaching process - by ozone bleaching of acidified pulp at high consistency, diluting to lower consistency, and making alkaline for peroxy bleaching
EP0276608A1 (en) * 1986-12-31 1988-08-03 Beghin-Say Societe Anonyme Process for treating a paper slurry with ozone

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5211811A (en) * 1989-02-15 1993-05-18 Union Camp Patent Holding, Inc. Process for high consistency oxygen delignification of alkaline treated pulp followed by ozone delignification
US5409570A (en) * 1989-02-15 1995-04-25 Union Camp Patent Holding, Inc. Process for ozone bleaching of oxygen delignified pulp while conveying the pulp through a reaction zone
USRE36033E (en) * 1989-08-16 1999-01-12 Maschinenfabrik Andritz Actiengesellschaft Process for the comminution of materials and plants for carrying out the process
US5441603A (en) * 1990-05-17 1995-08-15 Union Camp Patent Holding, Inc. Method for chelation of pulp prior to ozone delignification
US5296099A (en) * 1990-05-17 1994-03-22 Union Camp Holding, Inc. Environmentally improved process for bleaching lignocellulosic materials with oxygen, ozone and chlorine dioxide
US5181989A (en) * 1990-10-26 1993-01-26 Union Camp Patent Holdings, Inc. Reactor for bleaching high consistency pulp with ozone
EP0512098B1 (en) * 1990-10-26 1998-03-04 Union Camp Patent Holding, Inc. Pulp bleaching method and reactor
US5174861A (en) * 1990-10-26 1992-12-29 Union Camp Patent Holdings, Inc. Method of bleaching high consistency pulp with ozone
US5863389A (en) * 1990-10-26 1999-01-26 Union Camp Patent Holding, Inc. Pulp bleaching reactor for dispersing high consistency pulp into a gaseous bleaching agent containing ozone
WO1992007999A1 (en) * 1990-10-26 1992-05-14 Union Camp Patent Holding, Inc. Pulp bleaching reactor and method
US5520783A (en) * 1990-10-26 1996-05-28 Union Camp Patent Holding, Inc. Apparatus for bleaching high consistency pulp with ozone
US5472572A (en) * 1990-10-26 1995-12-05 Union Camp Patent Holding, Inc. Reactor for bleaching high consistency pulp with ozone
EP0492040A1 (en) * 1990-12-21 1992-07-01 Kamyr, Inc. Tumbling ozone reactor for paper pulp
EP0492039A1 (en) * 1990-12-27 1992-07-01 Kamyr, Inc. Pneumatic reactor ozone bleaching of paper pulp
US5087326A (en) * 1991-02-20 1992-02-11 Union Camp Patent Holding, Inc. Rotating pulp bleaching reactor having inner and outer shells and lifting means on the interior surface of the inner shell
US5451296A (en) * 1991-05-24 1995-09-19 Union Camp Patent Holding, Inc. Two stage pulp bleaching reactor
EP0627029A4 (en) * 1992-01-15 1995-12-06 Union Camp Patent Holding Pulp bleaching apparatus and method.
EP0627029A1 (en) * 1992-01-15 1994-12-07 Union Camp Patent Holding, Inc. Pulp bleaching apparatus and method
US6174409B1 (en) 1997-09-19 2001-01-16 American Air Liquide Inc. Method to improve final bleached pulp strength properties by adjusting the CI02:03 ration within a single (D/Z) stage of the bleaching process
AP1537A (en) * 2000-07-06 2006-01-10 Servier Lab A crystalline form of perindopril tert-butylamine salt.

Also Published As

Publication number Publication date
BR8804806A (en) 1989-04-25
NO884128L (en) 1989-03-20
NO174781C (en) 1994-07-06
NO884128D0 (en) 1988-09-16
JP2731822B2 (en) 1998-03-25
DE308314T1 (en) 1989-10-05
JPH0197290A (en) 1989-04-14
FI884267A (en) 1989-03-18
FI93867B (en) 1995-02-28
FI884267A0 (en) 1988-09-16
CA1314664C (en) 1993-03-23
NO174781B (en) 1994-03-28
EP0308314B1 (en) 1992-11-11
DE3875893T2 (en) 1993-03-18
FI93867C (en) 1995-06-12
FR2620744A1 (en) 1989-03-24
ATE82340T1 (en) 1992-11-15
ES2035339T3 (en) 1993-04-16
DE3875893D1 (en) 1992-12-17

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