EP0441113A1 - Process for the chlorine-free bleaching of cellulosic pulp - Google Patents
Process for the chlorine-free bleaching of cellulosic pulp Download PDFInfo
- Publication number
- EP0441113A1 EP0441113A1 EP90890348A EP90890348A EP0441113A1 EP 0441113 A1 EP0441113 A1 EP 0441113A1 EP 90890348 A EP90890348 A EP 90890348A EP 90890348 A EP90890348 A EP 90890348A EP 0441113 A1 EP0441113 A1 EP 0441113A1
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- European Patent Office
- Prior art keywords
- stage
- eop
- pulp
- bleaching
- bleach
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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
- D21C9/1057—Multistage, with compounds cited in more than one sub-group D21C9/10, D21C9/12, D21C9/16
-
- 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
-
- 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
- this pulp suspension was fluidized and compressed O3-containing oxygen gas was pressed in.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Wood Science & Technology (AREA)
- Paper (AREA)
- Polysaccharides And Polysaccharide Derivatives (AREA)
- Artificial Filaments (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
- Detergent Compositions (AREA)
- General Preparation And Processing Of Foods (AREA)
- Jellies, Jams, And Syrups (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
Description
Die vorliegende Erfindung betrifft ein Verfahren zum chlorfreien Bleichen von Kunstfaserzellstoff mit Ozon nach einem dreistufigen Verfahren, bestehend aus einer Sauerstoffbleiche, die gegebenenfalls mit einer Wasserstoffperoxidbleiche kombiniert ist (EOP-Stufe), einer Ozonbleiche (Z-Stufe) und einer Peroxidbleiche (P-Stufe).The present invention relates to a process for chlorine-free bleaching of synthetic fiber pulp with ozone according to a three-stage process, consisting of an oxygen bleach, which is optionally combined with a hydrogen peroxide bleach (EOP stage), an ozone bleach (Z stage) and a peroxide bleach (P stage ).
Da Chlor ein giftiges, schwer kontrollierbares Gas ist, und chlorhältige Bleichmittel chlorierte Abwasserinhaltsstoffe produzieren, welche in Zukunft nicht mehr toleriert werden können, wurden für das Bleichen von Zellstoffen Verfahren entwickelt, die O₂, H₂O oder O₃ in verschiedenen Kombinationen und unter verschiedenen Bedingungen als umweltschonende Alternative einsetzen.Since chlorine is a toxic gas that is difficult to control, and chlorine-containing bleaches produce chlorinated wastewater constituents that can no longer be tolerated in the future, processes have been developed for bleaching cellulose that use O₂, H₂O or O₃ in various combinations and under different conditions as environmentally friendly Use alternative.
Ein Verfahren der eingangs genannten Art ist aus Beispiel 24 (das sich auf die Beispiele 10, 2 und 1 zurückbezieht), der US-PS 4 216 054 bekannt. Hier wird Douglasfichtenzellstoff mit relativ schlechtem Ergebnis (Weißgrad 74,6) gebleicht.A method of the type mentioned at the outset is known from Example 24 (which relates to Examples 10, 2 and 1), US Pat. No. 4,216,054. Here Douglas fir pulp is bleached with a relatively poor result (whiteness 74.6).
Die CA-PS 11 03 409 beschreibt ein Bleichverfahren, das drei Ozonstufen in Serie verwendet und das ozonhältige Restgas aus der 3.Ozonbleichstufe in die 1. Ozonbleichstufe einbringt, um den restlichen Ozongehalt auszunützen. Das in der 1.Ozonbleichstufe anfallende Restgas wird nicht mehr weiter verwendet.CA-PS 11 03 409 describes a bleaching process which uses three ozone stages in series and introduces the ozone-containing residual gas from the 3rd ozone bleaching stage into the 1st ozone bleaching stage in order to utilize the remaining ozone content. The residual gas generated in the 1st ozone bleaching stage is no longer used.
Es ist Aufgabe der vorliegenden Erfindung, das Verfahren der eingangs genannten Art dahingehend zu verbessern, daß es kostengünstiger, umweltschonender und energiesparender durchgeführt werden kann.It is an object of the present invention to improve the method of the type mentioned at the outset in such a way that it can be carried out more economically, in an environmentally friendly manner and in an energy-saving manner.
Diese Aufgabe wird bei einem Verfahren der eingangs genannten Art erfindungsgemäß dadurch gelöst, daß der Restsauerstoffgehalt der Abluft der Z-Stufe in der EOP-Stufe vollstandig zur Reaktion gebracht wird und daß das Abwasser der Z-Stufe, dessen pH-Wert vorzugsweise unter 3 liegt, zur Verdünnung zwischen EOP- und Z-Stufe und/oder zur Entaschung des Zellstoffs nach der Bleiche eingesetzt wird.This object is achieved according to the invention in a process of the type mentioned at the outset in that the residual oxygen content of the exhaust air from the Z stage is completely reacted in the EOP stage and that the waste water from the Z stage, the pH of which is preferably below 3 , is used for dilution between the EOP and Z stages and / or for ash removal from the pulp after bleaching.
Es wurde nämlich überraschend gefunden, daß es bei einem Bleichverfahren der eingangs genannten Art möglich ist, die Verfahrensparameter so zu wählen, daß der Restsauerstoffgehalt der Abluft der Z-Stufe in der EOP-Stufe vollständig zur Reaktion gebracht wird. Dadurch ist die erfindungsgemäße Chemikalienrückführung möglich und die oben erwähnte Aufgabe gelöst.It has been surprisingly found that it is possible in a bleaching process of the type mentioned at the outset to select the process parameters in such a way that the residual oxygen content of the exhaust air from the Z stage is completely reacted in the EOP stage. As a result, the chemical recycling according to the invention is possible and the above-mentioned object is achieved.
Bei der Wahl der Verfahrensparameter ist folgendes zu beachten:
In der EOP-Stufe muß die Kappa-Zahl des Zellstoffes soweit herabgesetzt werden, daß man im folgenden mit einer einzigen Ozonstufe auskommt. Pro Ozonstufe darf nicht zu stark gebleicht werden, weil sonst die Qualität des Zellstoffs leidet. Der Ozonbedarf in der O-Stufe (Z-Stufe) wird durch die Temperatureinstellung in der EOP-Stufe so geregelt, daß die Gesamtmenge an Restgas in der EOP-Stufe eingesetzt werden kann. Wegen des geringen Ozoneinsatzes kann die Temperatur in der Z-Stufe relativ hoch gewählt werden, sodaß der Energieaufwand für die Kühlung und das Wiederaufheizen des Zellstoffs zwischen den Stufen gering gehalten werden kann. Die Aktivierung über die Temperatur und die NaOH-Menge in der EOP-Stufe wird so gewählt, daß die Gesamtmenge an Restgas aus der O₃-Stufe hier zur Reaktion gebracht wird.When choosing the process parameters, note the following:
In the EOP stage, the kappa number of the pulp must be reduced to such an extent that one single ozone stage can be used in the following. Do not bleach too much per ozone level, otherwise the quality of the pulp will suffer. The ozone requirement in the O stage (Z stage) is regulated by the temperature setting in the EOP stage so that the total amount of residual gas can be used in the EOP stage. Because of the low use of ozone, the temperature in the Z stage can be selected to be relatively high, so that the energy expenditure for the cooling and the reheating of the pulp between the stages can be kept low. The activation via the temperature and the amount of NaOH in the EOP stage is chosen so that the total amount of residual gas from the O₃ stage is reacted here.
Die EOP- und die Z-Stufe können beim erfindungsgemäßen Verfahren von der Chemikalienbilanz her als eine Einheit betrachtet werden. Die Z-Stufe kann als LC(low consistency)-Stufe, d.h. unter 4 Masse-% ATS, oder als MC(mediumconsistency)-Stufe, d.h. in einem Bereich von 5 - 20 Masse % ATS, vorzugsweise 7 - 15 % ATS, nach A 2494/89 gefahren werden.In the method according to the invention, the EOP and the Z stage can be regarded as one unit from the chemical balance. The Z level can be an LC (low consistency) level, i.e. below 4 mass% ATS, or as MC (medium consistency) level, i.e. in a range of 5-20% by mass ATS, preferably 7-15% ATS, according to A 2494/89.
Die zweite Möglichkeit ist natürlich dann besonders vorteilhaft, wenn auch die EOP-Stufe und die P-Stufe als MC-Stufe gefahren werden, weil dann naturgemäß das Verdünnen vor der Z-Stufe und das Eindichten vor der P-Stufe entfällt bzw. nur in einem wesentlich geringerem Ausmaß durchgeführt werden muß.The second option is of course particularly advantageous if the EOP stage and the P stage are also used as the MC stage, because then of course there is no need for dilution before the Z stage and sealing before the P stage to a much lesser extent.
Es gibt verschiedene Verfahrensparameter, die dazu geeignet sind, den Sauerstoffbedarf der EOP-Stufe auf den Rest-Sauerstoffgehalt der Abluft der Z-Stufe abzustimmen. Es wird jedoch nach einer Ausgestaltung der Erfindung bevorzugt, daß die Temperatur, der NaOH-Einsatz und das O₂/H₂O₂-Verhältnis in der EOP-Stufe so geregelt werden, daß der Sauerstoffverbrauch bei konstantem Umsatz auf den Rest-Sauerstoffgehalt der Abluft der Z-Stufe abgestimmt ist.There are various process parameters that are suitable for coordinating the oxygen requirement of the EOP stage with the residual oxygen content of the exhaust air of the Z stage. However, it is preferred according to one embodiment of the invention that the temperature, the NaOH use and the O₂ / H₂O₂ ratio in the EOP stage are controlled so that the oxygen consumption with constant conversion to the residual oxygen content of the exhaust air of the Z- Level is matched.
Es ist zweckmäßig, wenn die Temperatur der EOP-Stufe 70 - 100°C, vorzugsweise 75°C beträgt, wenn die NaOH-Konzentration der EOP-Stufe zwischen 2,5 - 5 Masse-%, bezogen auf Zellstoff, atro gebleicht, beträgt und wenn die Konzentration von O₂ im Gemisch O₂ - H₂O₂ der EOP-Stufe 50 - 100 Masse-% und die Konzentration von H₂O₂ 0 - 50 Masse-% beträgt.It is expedient if the temperature of the EOP stage is 70-100.degree. C., preferably 75.degree. C., if the NaOH concentration of the EOP stage is between 2.5-5% by mass, based on pulp, bleached dry and if the concentration of O₂ in the mixture O₂ - H₂O₂ of the EOP stage 50 - 100 mass% and the concentration of H₂O₂ is 0 - 50% by mass.
Weiters ist es zweckmäßig, wenn die Z-Stufe mit einem O₂/O₃-Gemisch mit maximal 10 Masse-% O₃ betrieben wird und die Temperatur der Z-Stufe 40 - 70°C, vorzugsweise 50 - 60° C, beträgt.Furthermore, it is expedient if the Z stage is operated with an O₂ / O₃ mixture with a maximum of 10% by mass of O₃ and the temperature of the Z stage is 40-70 ° C, preferably 50-60 ° C.
Die Bleichfolge EOP - Z - P beginnt mit dem Einleiten des Abgases aus der Z-Stufe in ein Gemisch von Kunstfaserzellstoff, NaOH und H₂O₂.The bleaching sequence EOP - Z - P begins with the introduction of the exhaust gas from the Z stage into a mixture of synthetic fiber pulp, NaOH and H₂O₂.
Aufgrund der eingestellten Verfahrensparameter wird ein 50%-iger Umsatz des eingesetzten O₂ mit dem Zellstoff erzielt. Dadurch ist es möglich, bei Kunstfaserzellstoff die Kappa-Zahl herabzusetzen. Der Kappa-Wert des Kunstfaserzellstoffes soll, wenn er in die Z-Stufe eingebracht wird, maximal bei 2,0, vorzugsweise bei 1,8 - 2,5 liegen.Due to the set process parameters, a 50% conversion of the O₂ used is achieved with the pulp. This makes it possible to reduce the kappa number for synthetic fiber pulp. The kappa value of the synthetic fiber pulp, when introduced into the Z stage, should be a maximum of 2.0, preferably 1.8-2.5.
Durch diese Kappa-Zahl gelingt es, bei Kunstfaserzellstoffen mit einer Z-Stufe auszukommen. Es ist bekannt, daß Papierzellstoffe dagegen weitaus mehr Ozon verbrauchen.This Kappa number makes it possible to get by with a Z level in synthetic fiber pulps. Paper pulps, on the other hand, are known to consume far more ozone.
Wird die Z-Stufe als LC-Prozeß gefahren, so sind 0,5 - 10% O₃ ind O₂ ausreichend. Die geringe O₃-Menge ermöglicht Temperaturen zwischen 50 - 60°C, sodaß gegenüber der vorangegangenen Stufe die Temperatur unverändert ist und keine Energieverluste auftreten.If the Z stage is operated as an LC process, 0.5 - 10% O₃ ind O₂ are sufficient. The small amount of O₃ allows temperatures between 50 - 60 ° C, so that the temperature is unchanged compared to the previous stage and no energy losses occur.
Sowohl Abgas als auch Abwasser wird vollständig zur Reaktion gebracht.Both exhaust gas and waste water are reacted completely.
Die P-Stufe, die der Z-Stufe folgt, ist ebenfalls der Temperatur der Vorstufe angepaßt, sie verlauft zwischen 60 - 70°C und benötigt weniger H₂O₂ als üblich.The P stage, which follows the Z stage, is also adapted to the temperature of the preliminary stage, it runs between 60 - 70 ° C and requires less H₂O₂ than usual.
Die nachfolgenden Beispiele sollen die Erfindung noch näher erläutern.The following examples are intended to explain the invention in more detail.
Sortierter Buchen-Kunstfaserzellstoff ungebleicht mit einer Kappazahl von 5,2, einer Viskosität vn 24,5 mPas und einem Weißgehalt Elrepho von 55,6 wird einer dreistufigen Bleiche unterzogen.Assorted beech synthetic fiber pulp unbleached with a kappa number of 5.2, a viscosity of 24.5 mPas and a white content Elrepho of 55.6 is subjected to a three-stage bleaching process.
Der Rohzellstoff mit einer Stoffdichte von 15% und einer Temperatur von 75°C wurde mit Natronlauge in einer Menge von
- 33 kg/t
- Zellstoff atro gebleicht (entsprechend 366 l NaOH-Lösung mit 90 g/l) und
- 10,8 l
- 50%-igem H₂O₂ versetzt
- 33 kg / t
- Bleached cellulose dry (corresponding to 366 l NaOH solution with 90 g / l) and
- 10.8 l
- 50% H₂O₂ added
Die Stoffsuspension wurde anschließend in einem "High-Shear"-MC-Mixer behandelt. In diesem Mixer wurden nochmals 5,5 Nm³ Abgas aus der Z-Stufe zugeführt.The stock suspension was then treated in a "high-shear" MC mixer. A further 5.5 Nm³ of exhaust gas from the Z stage were fed into this mixer.
Dieses Gemisch wurde über ein Vorreaktionsrohr mit 3 min Verweilzeit in einen Aufwärts-Bleichturm geleitet, welcher eine Reaktionszeit von 2 h 45 min gestattet.This mixture was passed through a pre-reaction tube with a residence time of 3 min into an upward bleaching tower which allowed a reaction time of 2 h 45 min.
In der Folge wurde der Zellstoff auf zwei Vakuumtrommelfiltern und einer Schneckenpresse von der anhanftenden Flotte befreit. Das Filtrat der Schneckenpresse (3,3 m³/t Zellstoff) wurde im Gegenstrom gemeinsam mit weiteren 3,3 m³ Frischwasser über Waschrohre auf den Filtern zur Wäsche verwendet.Subsequently, the pulp was freed from the adhering liquor on two vacuum drum filters and a screw press. The filtrate from the screw press (3.3 m³ / t cellulose) was used in countercurrent with other 3.3 m³ fresh water via washing pipes on the filters for washing.
Damit konnte die organische Begleitfracht auf 3 kg OTS pro t Zellstoff gesenkt werden. Der Weißgrad betrug 75,4%; die Kappazahl 1,89; die Viskosität 24,0 mPas.The organic accompanying freight could thus be reduced to 3 kg OTS per t cellulose. The whiteness was 75.4%; the kappa number 1.89; the viscosity 24.0 mPas.
Nach der Schneckenpresse wurde der Zellstoff mit Retourwasser des Vakuumtrommelfilters nach der Z-Stufe auf eine Stoffdichte von 2% verdünnt und mit Schwefelsäure ein pH von 3 eingestellt. In einer OZON-Bleichanlage bekannter Bauart (Waagner-Biro) wurde die Sauerstoffsuspension von 2% Stoffdichte im Kreislauf über einen Injektor gefördert. Schrittweise wurden über diesen Injektor 1,45 g OZON pro kg Zellstoff eingetragen. Die Verweilzeit im Reaktor betrug 20 min, die Temperatur 51°C.After the screw press, the pulp was diluted to a consistency of 2% with return water from the vacuum drum filter after the Z stage and a pH of 3 was set using sulfuric acid. In an OZON bleaching plant of known design (Waagner-Biro), the oxygen suspension of 2% consistency was conveyed in a circuit via an injector. 1.45 g of OZONE per kg of pulp were introduced gradually via this injector. The residence time in the reactor was 20 min, the temperature 51 ° C.
Anschließend wurde der Zellstoff wieder gewaschen. Das saure Filtrat wurde zum Entaschen des Zellstoffs vor dem letzten Filter eingesetzt.The pulp was then washed again. The acidic filtrate was used to ash the pulp before the last filter.
Die Analysenwerte des Zellstoffs waren:
Weißgrad 78,3; Kappazahl 0,97; Viskosität 22,0.The pulp analysis values were:
Whiteness 78.3; Kappa number 0.97; Viscosity 22.0.
Die 3.Stufe erfolgt unter Zugabe von 4 kg NaOH/t Zellstoff und 7 kg H₂O₂ (50 %-ig) bei 65°C und 13% Stoffdichte bei einer Verweilzeit von 4 h.The 3rd stage is carried out with the addition of 4 kg NaOH / t pulp and 7 kg H₂O₂ (50%) at 65 ° C and 13% consistency with a residence time of 4 h.
In weiterer Folge wurde auf zwei Vakuumtrommelfiltern gewaschen. Vor dem zweiten Filter wurde mit dem Filtrat der Z-Stufe angesäuert, um den Aschegehalt des Zellstoffs auf 0,06% zu senken.Subsequently, washing was carried out on two vacuum drum filters. The Z-stage filtrate was acidified in front of the second filter in order to reduce the ash content of the pulp to 0.06%.
Fertigstoffanalysen:
Im Labor wurde eine kontinuierliche Versuchsapparatur zur 3 O₃-Bleiche betrieben, wobei über einen Injektor O₃-haltiger Sauerstoff in eine 2%-ige Zellstoffsuspension eingetragen wurde. Das Abgas wurde in einem Druckbehälter gesammelt, durch Eindrücken von Wasser komprimiert und für die diskontinuierlichen Versuche der 1. Bleichstufe (EOP) in einem gerührten Laborautoklav eingesetzt.A continuous test apparatus for 3 O₃ bleaching was operated in the laboratory, O₃-containing oxygen being introduced into a 2% pulp suspension via an injector. The exhaust gas was collected in a pressure vessel, compressed by pressing in water and used for the batch tests of the 1st bleaching stage (EOP) in a stirred laboratory autoclave.
Die 3.Bleichstife (P) wurde ebenfalls diskontinuierlich durchgeführt.
Zellstoff nach der 1.Bleichstufe von Beispiel 1 wurde entnommen und im Labor weiter verarbeitet.
(Weißgehalt 75,4%, Kappazahl 1,89, Viskosität 24,0 mPas)Pulp after the 1st bleaching stage of Example 1 was removed and further processed in the laboratory.
(White content 75.4%, kappa number 1.89, viscosity 24.0 mPas)
Dieser wurde abgepreßt auf 20% Stoffdichte und mit verdünnter Schwefelsäure auf 11% Stoffdichte verdünnt, sodaß der pH-Wert 2,9 betrug.This was pressed to 20% consistency and diluted with dilute sulfuric acid to 11% consistency, so that the pH was 2.9.
In einem"High-Saher"-Mixer wurde diese Zellstoffsuspension fluidisiert und komprimiertes O₃-hältiges Sauerstoffgas eingedrückt.In a "high-saher" mixer, this pulp suspension was fluidized and compressed O₃-containing oxygen gas was pressed in.
Die Mischzeit betrug 15 s, die Reaktionszeit 180 s, der O₃-Druck 5,1 bar, die Temperatur 50°C.The mixing time was 15 s, the reaction time 180 s, the O₃ pressure 5.1 bar, the temperature 50 ° C.
Der spezifische O₃-Einsatz lag bei 1,50 g O₃/kg Zellstoff atro gebleicht, der O₃-Verbrauch bei 1,40 g.The specific O₃ use was 1.50 g O₃ / kg cellulose bleached, the O₃ consumption at 1.40 g.
Die Analysendaten des dabei erhaltenen Zellstoffes waren:
Dieser Zellstoff wurde einer Laborendbleiche (P-Stufe) unterworfen:
Fertigstoffdaten:
This pulp was subjected to laboratory bleaching (P level):
Finished material data:
Claims (7)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT261/90 | 1990-02-07 | ||
| AT0026190A AT395028B (en) | 1990-02-07 | 1990-02-07 | METHOD FOR CHLORINE-FREE BLEACHING OF FIBER FIBER |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0441113A1 true EP0441113A1 (en) | 1991-08-14 |
| EP0441113B1 EP0441113B1 (en) | 1994-09-28 |
Family
ID=3485841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP90890348A Expired - Lifetime EP0441113B1 (en) | 1990-02-07 | 1990-12-20 | Process for the chlorine-free bleaching of cellulosic pulp |
Country Status (22)
| Country | Link |
|---|---|
| US (1) | US5145557A (en) |
| EP (1) | EP0441113B1 (en) |
| JP (1) | JPH04300380A (en) |
| AT (2) | AT395028B (en) |
| BR (1) | BR9100516A (en) |
| CA (1) | CA2035698C (en) |
| CZ (1) | CZ280077B6 (en) |
| DE (1) | DE59007341D1 (en) |
| DK (1) | DK0441113T3 (en) |
| ES (1) | ES2061008T3 (en) |
| FI (1) | FI98077C (en) |
| HR (1) | HRP930456A2 (en) |
| IN (1) | IN174833B (en) |
| LT (1) | LT3392B (en) |
| LV (1) | LV10514B (en) |
| NO (1) | NO178079C (en) |
| PL (1) | PL169421B1 (en) |
| RU (1) | RU2040616C1 (en) |
| SI (1) | SI9110206B (en) |
| SK (1) | SK278326B6 (en) |
| YU (1) | YU47388B (en) |
| ZA (1) | ZA91840B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0480469A2 (en) * | 1990-10-12 | 1992-04-15 | Alcell Technologies Inc. | Chlorine-free wood pulps and process of making |
| EP0514901A2 (en) * | 1991-05-21 | 1992-11-25 | Air Products And Chemicals, Inc. | Dye removal in oxygen color stripping of secondary fibers |
| FR2695947A1 (en) * | 1992-09-18 | 1994-03-25 | Saint Gobain Papier Bois Gie C | Chlorine-free bleaching process for chemical paper pulp |
| WO1997023666A1 (en) * | 1995-12-22 | 1997-07-03 | Lenzing Aktiengesellschaft | Cellulose moulded article and method of producing same |
| EP0665912B1 (en) * | 1992-10-23 | 1998-02-11 | Macmillan Bloedel Limited | Improved ozone bleaching |
| WO2016189205A1 (en) * | 2015-05-27 | 2016-12-01 | Kemira Oyj | Method for reducing pulp viscosity in production of dissolving pulp |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1006056A3 (en) * | 1992-07-06 | 1994-05-03 | Solvay Interox | Method of laundering of chemical pulp. |
| SE500113C2 (en) * | 1992-07-09 | 1994-04-18 | Kamyr Ab | Method of bleaching pulp for disposal of released metals |
| US5374333A (en) * | 1992-07-30 | 1994-12-20 | Kamyr, Inc. | Method for minimizing pulp mill effluents |
| SE500335C2 (en) * | 1992-10-26 | 1994-06-06 | Sca Wifsta Oestrand Ab | Bleaching of sulfate pulp with peroxide-ozone-peroxide |
| US6210527B1 (en) | 1994-03-14 | 2001-04-03 | The Boc Group, Inc. | Pulp bleaching method wherein an ozone bleaching waste stream is scrubbed to form an oxygen containing stream |
| SE504424C2 (en) * | 1994-11-04 | 1997-02-10 | Kvaerner Pulping Tech | Ways to precipitate transition metals and alkaline earth metals from bleaching liquids by adding alkaline liquid |
| SE516030C2 (en) * | 1994-11-14 | 2001-11-12 | Aga Ab | Regeneration of a gas mixture from an ozone bleaching stage |
| US5656130A (en) * | 1995-04-28 | 1997-08-12 | Union Camp Holding, Inc. | Ambient temperature pulp bleaching with peroxyacid salts |
| CA2239855C (en) * | 1995-12-07 | 2002-07-02 | Beloit Technologies, Inc. | Oxygen delignification of medium consistency pulp slurry |
| EP1728918A3 (en) * | 2005-05-12 | 2006-12-13 | Voith Patent GmbH | Proces for removing impurities from an aqueous fibrous suspension |
| US9339058B2 (en) | 2012-04-19 | 2016-05-17 | R. J. Reynolds Tobacco Company | Method for producing microcrystalline cellulose from tobacco and related tobacco product |
| SE538064C2 (en) * | 2014-06-17 | 2016-02-23 | Valmet Oy | Method of producing dissolving pulp from lignocellulosic materials |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4372812A (en) * | 1978-04-07 | 1983-02-08 | International Paper Company | Chlorine free process for bleaching lignocellulosic pulp |
| US4619733A (en) * | 1983-11-30 | 1986-10-28 | Kooi Boon Lam | Pollution free pulping process using recycled wash effluent from multiple bleach stages to remove black liquor and recovering sodium hydroxide from the black liquor |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4196043A (en) * | 1970-12-21 | 1980-04-01 | Scott Paper Company | Kraft pulp bleaching and recovery process |
| CA966604A (en) * | 1970-12-21 | 1975-04-29 | Scott Paper Company | Kraft pulp bleaching and recovery process |
| JPS5430902A (en) | 1977-06-27 | 1979-03-07 | Seisan Kaihatsu Kagaku Kenkyus | Industrial multistage pulp bleaching method |
| US4216054A (en) * | 1977-09-26 | 1980-08-05 | Weyerhaeuser Company | Low-consistency ozone delignification |
| US4283251A (en) * | 1980-01-24 | 1981-08-11 | Scott Paper Company | Ozone effluent bleaching |
| AT384837B (en) * | 1985-06-27 | 1988-01-11 | Steyrermuehl Papier | Process and arrangement for the delignification of pulp with oxygen |
-
1990
- 1990-02-07 AT AT0026190A patent/AT395028B/en not_active IP Right Cessation
- 1990-12-20 EP EP90890348A patent/EP0441113B1/en not_active Expired - Lifetime
- 1990-12-20 ES ES90890348T patent/ES2061008T3/en not_active Expired - Lifetime
- 1990-12-20 DE DE59007341T patent/DE59007341D1/en not_active Expired - Fee Related
- 1990-12-20 DK DK90890348.7T patent/DK0441113T3/en not_active Application Discontinuation
- 1990-12-20 AT AT90890348T patent/ATE112338T1/en not_active IP Right Cessation
-
1991
- 1991-01-28 IN IN85CA1991D patent/IN174833B/en unknown
- 1991-02-05 CA CA002035698A patent/CA2035698C/en not_active Expired - Fee Related
- 1991-02-05 ZA ZA91840A patent/ZA91840B/en unknown
- 1991-02-06 PL PL91288978A patent/PL169421B1/en unknown
- 1991-02-06 NO NO910455A patent/NO178079C/en unknown
- 1991-02-06 RU SU914894510A patent/RU2040616C1/en active
- 1991-02-06 SI SI9110206A patent/SI9110206B/en unknown
- 1991-02-06 SK SK280-91A patent/SK278326B6/en unknown
- 1991-02-06 CZ CS91280A patent/CZ280077B6/en unknown
- 1991-02-06 YU YU20691A patent/YU47388B/en unknown
- 1991-02-07 US US07/652,027 patent/US5145557A/en not_active Expired - Lifetime
- 1991-02-07 BR BR919100516A patent/BR9100516A/en not_active Application Discontinuation
- 1991-02-07 JP JP3016575A patent/JPH04300380A/en active Pending
- 1991-02-07 FI FI910601A patent/FI98077C/en active IP Right Grant
-
1993
- 1993-01-12 LV LVP-93-21A patent/LV10514B/en unknown
- 1993-03-23 HR HR930456A patent/HRP930456A2/en not_active Application Discontinuation
- 1993-07-02 LT LTIP753A patent/LT3392B/en unknown
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4372812A (en) * | 1978-04-07 | 1983-02-08 | International Paper Company | Chlorine free process for bleaching lignocellulosic pulp |
| US4619733A (en) * | 1983-11-30 | 1986-10-28 | Kooi Boon Lam | Pollution free pulping process using recycled wash effluent from multiple bleach stages to remove black liquor and recovering sodium hydroxide from the black liquor |
Non-Patent Citations (1)
| Title |
|---|
| ABSTRACT BULLETIN OF THE INSTITUTE OF PAPER CHEMISTRY. vol. 52, no. 1, Juli 1981, APPLETON US Seite 70 Christensen,P.K. et al.: "Bleaching of sulfite pulp with oxygen and ozone." * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0480469A2 (en) * | 1990-10-12 | 1992-04-15 | Alcell Technologies Inc. | Chlorine-free wood pulps and process of making |
| EP0480469A3 (en) * | 1990-10-12 | 1994-06-01 | Alcell Tech Inc | Chlorine-free wood pulps and process of making |
| EP0514901A2 (en) * | 1991-05-21 | 1992-11-25 | Air Products And Chemicals, Inc. | Dye removal in oxygen color stripping of secondary fibers |
| EP0514901A3 (en) * | 1991-05-21 | 1993-03-17 | Air Products And Chemicals, Inc. | Oxygen color stripping in secondary fiber recovery |
| FR2695947A1 (en) * | 1992-09-18 | 1994-03-25 | Saint Gobain Papier Bois Gie C | Chlorine-free bleaching process for chemical paper pulp |
| EP0665912B1 (en) * | 1992-10-23 | 1998-02-11 | Macmillan Bloedel Limited | Improved ozone bleaching |
| WO1997023666A1 (en) * | 1995-12-22 | 1997-07-03 | Lenzing Aktiengesellschaft | Cellulose moulded article and method of producing same |
| WO2016189205A1 (en) * | 2015-05-27 | 2016-12-01 | Kemira Oyj | Method for reducing pulp viscosity in production of dissolving pulp |
| US10513824B2 (en) | 2015-05-27 | 2019-12-24 | Kemira Oyj | Method for reducing pulp viscosity in production of dissolving pulp |
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