EP0501059B1 - Aufschlussverfahren durch Dampfexplosion zur Papierherstellung - Google Patents

Aufschlussverfahren durch Dampfexplosion zur Papierherstellung Download PDF

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Publication number
EP0501059B1
EP0501059B1 EP91306166A EP91306166A EP0501059B1 EP 0501059 B1 EP0501059 B1 EP 0501059B1 EP 91306166 A EP91306166 A EP 91306166A EP 91306166 A EP91306166 A EP 91306166A EP 0501059 B1 EP0501059 B1 EP 0501059B1
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EP
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Prior art keywords
cooking
process according
steam
chips
wood fragments
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EP91306166A
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English (en)
French (fr)
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EP0501059A1 (de
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Bohuslav Vaclav Kokta
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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
    • D21C1/00—Pretreatment of the finely-divided materials before digesting
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21B—FIBROUS RAW MATERIALS OR THEIR MECHANICAL TREATMENT
    • D21B1/00—Fibrous raw materials or their mechanical treatment
    • D21B1/04—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres
    • D21B1/12—Fibrous raw materials or their mechanical treatment by dividing raw materials into small particles, e.g. fibres by wet methods, by the use of steam
    • D21B1/30—Defibrating by other means
    • D21B1/36—Explosive disintegration by sudden pressure reduction

Definitions

  • This invention relates to a steam explosion pulping process for papermaking.
  • CTMP/CMP ultra-high-yield chemithermomechanical or chemimechanical pulping
  • the steam explosion pulping process consists of the chemical impregnation of chips, short duration saturated steam cooking at temperatures varying from 180°C to 210°C, pressure release, refining and bleaching (if necessary).
  • the object of this invention is to provide a process in which additional yield saving and brightness level increase and cost decrease are obtained when compared to the previous invention of Kokta, CA-A-1 230 208 (equivalent to EP-A-284585) by substituting sodium hydroxide with milder swelling agents selected from: a carbonate or bicarbonate of ammonium, an alkaline earth or alkali metal, or magnesium chloride.
  • EP-A-487793 which forms part of the state of the art by virtue of Article 54(3), discloses a process for producing pulp suitable for making paper, which comprised the steps of impregnating wood fragments with an alkaline aqueous liquor including at least one soluble sulphite to provide hydrophylic groups and/or act as an antioxidant, steam cooking the impregnated wood fragments with saturated steam at superatmospheric pressure and at an elevated temperature; subjecting the cooked wood fragments to explosive decompression partially to defibrate same; and refining the softened and defibrated fragments to provide pulp.
  • the reactor is pressurised with cool nitrogen prior to explosive decompression and the liquor generally contains a strong base.
  • the major problems accompanying previous processes using explosive decompression are believed to have been degradation due to the oxidation of wood and acid hydrolysis leading to loss in brightness, deterioration of fiber and paper properties and loss of yield.
  • the approach adopted by this invention is thereto to attempt to curtail hydrolytic and oxidative wood degradation and thereby to protect against loss of yield, brightness and fiber strength.
  • the loss of fiber strength will be particularly great if the degree of polymerisation of the cellulose falls below the critical value which is about 500-600. Hydrolytic degradation will also cause yield lowss due mainly to degradation of hemi-cellulose.
  • the process of this invention tries to achieve a positive improvement in the strength of the paper that will be produced from the fibers by increasing the number of hydrophilic groups on the fiber surfaces thereby adding to the potential sites for hydrogen bonding.
  • Claim 1 sets out the conditions in more detail, in particular the choice of swelling agent, which is a mild base.
  • Claim 2 sets out alternative conditions, in which an inert gas is excluded during decompression.
  • the starting material will normally be chips in which the fibers are of a length suitable for paper making. Shavings could also be used but sawdust would be undesirable except as a minor part of the total furnish as the fibers are partially cut.
  • the chips should also, as is well known, be suitable in the sense of being free from bark and foreign matter.
  • impregnation is to protect the chips against oxidation during cooking and during transfer from the cooking vessel to the refiner. It is also an objective to provide a positive increase in strength by developing hydrophylic groups on the fiber surface during steam treatment. This will then provide additional sites for hydrogen bonding.
  • the preferred antioxidant is sodium sulphite Na2SO3 which also forms hydrophilic groups, and which is available at a low cost. It is used to provide a concentration of absorbed chemical of about 1 to 16% by weight. Concentrations below 4% would be used where brightness protection is unimportant and high strength is not required. Where, however, brightness is important the sodium sulphite should be at least 4%. If physical properties are important these will be improved by using a concentration of at least 4% sodium sulphite and will be further improved as the concentration is further increased towards 16%.
  • the concentration of the solution is preferably about the same as the percentage of chemical to be absorbed where there are equal quantities of chips and liquor.
  • a ton of chips of 50% consistency mixed with one ton of 8% solution will result in about 8% absorbed on the pulp.
  • Thorough impregnation is important so as to distribute the antioxidant evenly rather than depositing it just on the surface.
  • Other antioxidants that can be used are potassium sulphite or magnesium sulphite.
  • Ammonium sulphite could be used if cooking conditions are not severe, or with a buffer.
  • Complexing agents such as ethylene diamine tetracetic acid (EDTA), sodium diethylene triaminepentacetate (DTPA), sodium tripolyphosphate (TPF) and other complexing agents known in the art as being usable under alkaline conditions may be added to minimize the catalytic effect of metals such as iron on oxidative degradation.
  • a swelling agent to assist the antioxidant or hydrophilic agent in penetrating the wood and this contributes also to softening the chip.
  • Suitable swelling agents are sodium carbonate or sodium bicarbonate or magnesium carbonate any of which will contribute also to providing hydrophilic groups.
  • Other swelling agents that can be used and which may be desirable as auxiliary swelling agents for high density wood are zinc chloride, sodium chloride, sodium bromide, magnesium chloride, calcium isocyanate, Schweitzers solution, cupriethylenediamne (C.E.D.) tetraethylammonium hydroxide or dimethyldibenzylammonium hydroxide.
  • the concentration of swelling agent and conditions of swelling must be controlled in such a way as to avoid any dissolution of the hollocellulose.
  • the percentage of swelling agent in the impregnating solution will be in the range of about 1 to 4% depending on the agent and the conditions.
  • the impregnating solution must be alkaline and have enough free hydroxyl to be able to neutralize the liberated wood acids such as formic acid and acetic acid. Normally the starting pH is about 7.5 or higher and the final pH after steam cooking should be at least 6 or higher.
  • the time of impregnation at atmospheric pressure in holding tanks typically ranges from about 12 hours to 24 hours at a temperature of about 30°C to 60°C. Approximately equal weights of chips and of aqueous impregnating solution can be used. For industrial purposes, however, the time may be shortened to an hour or to minutes by impregnating with steam under pressure and at a higher temperature.
  • the pressure should be up to about 1 atmospheric extra pressure at a temperature of about 100°C to 110°C.
  • the chips should be compressed in advance of impregnation in cool solutions of chemicals. Under these conditions, penetration will be achieved in a shorter time. Penetration is what predominantly occurs; there is no significant cooking as evidenced by the fact that there is no significant sulphonic and carboxylic group increase.
  • the impregnated chips are steam cooked at a high temperature and pressure.
  • the temperature of cooking should be within the range of about 180°C to 210°C and preferably within the range 190-200°C, which is in excess of the temperatures considered possible according to the publications of Asplund and Higgins previously referred to. These temperatures correspond with a pressure of 1 MPa (10 atmospheres) for 180°C and 1.6 MPa (15.5 atmospheres) for 200°C. It is these high pressures and temperatures which make a very important contribution to ensuring excellent penetration of the chips by the cooking liquor and results in higher efficience of ionic groups formation on fiber surface.
  • the cooking may be preceded by steam flushing under low pressure steam at 100°C for a short period such as one minute.
  • steam flushing under low pressure steam at 100°C for a short period such as one minute.
  • This preliminary treatment is then followed by cooking for about 30 seconds to 6 minutes and preferably about 1 to 4 minutes.
  • the chips resulting from the explosive decompression are softened and partially defibrated.
  • Refining energies are usually low and can be expected to be in the range of 1.7 to 4 MJ/kg, hardwoods, CSF ⁇ 100 ml, which is considerably lower than that of conventional CMP and similar to that described in Kokta, CA-A-1 230 208 and US-A-4 798 651.
  • Time of impregnation 24 hours; temperature of impregnation: 60°C.
  • Liquid/chip ratio during impregnation was equal to 3.
  • Explosion pulps were prepared using vapor phase team cooking of chemically pretreated aspen wood chips at a cooking temperature of 190°C and cooking time 4 minutes.
  • Cooking took place using saturated steam in a laboratory batch reactor built by Stake Tech. Co. Cooking was preceded by one minute steam flushing at atmospheric pressure. After cooking, the pressure was instantaneously released and chips which exploded into the release vessel were washed and cooled down with one liter of tap water, and subsequently refined after being stored in a cold room. The reported amount of steam used for cooking varied from 0.5 to 1 kg of steam for 1 kg of chips. Yield was measured as follows: exploded chips (75 g) were washed with one liter of tap water and subsequently defibrated for 90 seconds in a laboratory blender at 2% consistency. The pulp was washed again with one liter of water, dried at 105°C to constant weight and the resulted weights were compared to the initial O.D. weight of chips.
  • Paper sheets were prepared and tested according to standard CPPA testing methods on 1.2 g sheets. Brightness (Elrepho) was evaluated on sheets made with deinosized water. Ionic content (sulfonate and carboxylate ions) was determined by means of conductometric titration.
  • the present invention consisting in substituting NaOH by agents such as carbonates or bicarbonates results not only in the yield and brightness advantage but also in cost decrease.

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

Claims (10)

  1. Verfahren zur Herstellung von zur Papiererzeugung geeignetem Halbstoff, welches die Schritte des Imprägnierens von Holzbruchstücken mit einer wäßrigen alkalischen Flüssigkeit, die zumindest ein lösliches Sulfit enthält, um hydrophile Gruppen zu liefern und/oder als Oxidationshemmer zu wirken, des Dampfkochens der imprägnierten Holzfragmente mit Sattdampf bei Überatmosphärendruck und bei einer erhöhten Temperatur; des Aussetzens der gekochten Holzfragmente einer schlagartigen Druckentlastung, um sie teilweise zu defibrieren; und des Raffinierens der erweichten und defibrierten Fragmente, um Halbstoff zu erhalten, worin die Flüssigkeit Magnesiumchlorid, oder ein Karbonat oder Bikarbonat von Ammonium, von einem Erdalkalimetall oder einem Alkalimetall mit Ausnahme von Natrium als Quellmittel umfaßt.
  2. Verfahren zur Herstellung von zur Papiererzeugung geeignetem Halbstoff, welches die Schritte des Imprägnierens von Holzbruchstücken mit einer wäßrigen alkalischen Flüssigkeit, die zumindest ein lösliches Sulfit enthält, um hydrophile Gruppen zu liefern und/oder als Oxidationshemmer zu wirken, des Dampfkochens der imprägnierten Holzfragmente mit Sattdampf bei Überatmosphärendruck und bei einer erhöhten Temperatur; des Aussetzens der gekochten Holzfragmente einer schlagartigen Druckentlastung ohne vorhergehendes weiteres Unter-Druck-Setzen mit kühlem Inertgas, um sie teilweise zu defibrieren; und des Raffinierens der erweichten und defibrierten Fragmente, um Halbstoff zu erhalten, worin die Flüssigkeit Magnesiumchlorid, oder ein Karbonat oder Bikarbonat von Ammonium, von einem Erdalkalimetall oder einem Alkalimetall als Quellmittel umfaßt.
  3. Verfahren nach Anspruch 1 oder 2, worin die Quellmittel in einer Menge von 1-4 Gew.-% von den Holzfragmenten absorbiert werden.
  4. Verfahren nach einem der Ansprüche 1 bis 3, worin das Dampfkochen bei einer Kochtemperatur im Bereich von 180°C bis 210°C durchgeführt wird und der Kochdruck etwa 1 MPa (10 atm) bis etwa 1,6 MPa (15,5 atm) beträgt.
  5. Verfahren nach Anspruch 4, worin die Kochtemperatur 190°C bis 200°C beträgt.
  6. Verfahren nach einem der vorhergehenden Ansprüche, worin dem Schritt des Imprägnierens das Ersetzen von Luft durch Sattdampf vorangeht.
  7. Verfahren nach einem der vorhergehenden Ansprüche, worin die Kochzeit 30 Sekunden bis 6 Minuten beträgt.
  8. Verfahren nach Anspruch 7, worin die Kochzeit 1 Minute bis 4 Minuten beträgt.
  9. Verfahren nach einem der vorhergehenden Ansprüche, worin während des Imprägnierungsschrittes zusätzlich ein kleiner Prozentsatz eines Hilfsquellmittels vorhanden ist.
  10. Verfahren nach Anspruch 8, worin das Hilfsquellmittel Zinkchlorid, Natriumchlorid, Natriumbromid, Magnesiumchlorid, Kalziumisocyanat, Schweizers-Reagenz, Kupfer(II)-ethylendiamin-tetraethylammoniumhydroxid oder -dimethyldibenzylammoniumhydroxid ist.
EP91306166A 1991-02-28 1991-07-08 Aufschlussverfahren durch Dampfexplosion zur Papierherstellung Expired - Lifetime EP0501059B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CA 2037275 CA2037275A1 (en) 1991-02-28 1991-02-28 Steam explosion pulping process for papermaking
CA2037275 1991-02-28

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EP0501059A1 EP0501059A1 (de) 1992-09-02
EP0501059B1 true EP0501059B1 (de) 1995-11-29

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Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000019004A1 (en) * 1998-09-25 2000-04-06 Stake Technology Ltd. Semi alkaline steam explosion treatment of fibrous material for the production of cellulose pulp
KR20010100017A (ko) 1998-12-30 2001-11-09 로날드 디. 맥크레이 화학물질을 첨가하는 증기 폭발 처리
US6413362B1 (en) 1999-11-24 2002-07-02 Kimberly-Clark Worldwide, Inc. Method of steam treating low yield papermaking fibers to produce a permanent curl
US8915644B2 (en) 2008-07-24 2014-12-23 Abengoa Bioenergy New Technologies, Llc. Method and apparatus for conveying a cellulosic feedstock
US9127325B2 (en) 2008-07-24 2015-09-08 Abengoa Bioenergy New Technologies, Llc. Method and apparatus for treating a cellulosic feedstock
CA2638157C (en) 2008-07-24 2013-05-28 Sunopta Bioprocess Inc. Method and apparatus for conveying a cellulosic feedstock
CA2638152C (en) 2008-07-24 2013-07-16 Sunopta Bioprocess Inc. Method and apparatus for treating a cellulosic feedstock
CA2650919C (en) 2009-01-23 2014-04-22 Sunopta Bioprocess Inc. Method and apparatus for conveying a cellulosic feedstock
CA2638150C (en) 2008-07-24 2012-03-27 Sunopta Bioprocess Inc. Method and apparatus for conveying a cellulosic feedstock
CA2638159C (en) 2008-07-24 2012-09-11 Sunopta Bioprocess Inc. Method and apparatus for treating a cellulosic feedstock
CA2638160C (en) 2008-07-24 2015-02-17 Sunopta Bioprocess Inc. Method and apparatus for conveying a cellulosic feedstock
CA2650913C (en) 2009-01-23 2013-10-15 Sunopta Bioprocess Inc. Method and apparatus for conveying a cellulosic feedstock
PL2467532T3 (pl) 2009-08-24 2014-11-28 Abengoa Bioenergy New Tech Llc Sposób wytwarzania etanolu i współproduktów z biomasy celulozowej
CN103362008A (zh) * 2012-04-01 2013-10-23 中国科学院过程工程研究所 一种以碱木质素为胶粘剂的汽爆秸秆生态板制备方法
CN104404803B (zh) * 2014-08-29 2016-08-17 济南米铎碳新能源科技有限公司 秸秆组分分离及秸秆组分全利用的方法
FR3026655A1 (fr) * 2014-10-01 2016-04-08 Commissariat Energie Atomique Dispositif de reduction de la taille de particules de biomasse a fonctionnement continu
CN106522004B (zh) * 2016-11-10 2018-10-23 北京化工大学 一种纤维素与半纤维素联合预处理装置
CN116334943A (zh) * 2023-04-12 2023-06-27 张志晔 物理蒸解法植物纤维提取工艺

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987001402A1 (en) * 1985-09-03 1987-03-12 Chaudhuri Punya B Method for producing of cellulosic pulp
EP0487793A1 (de) * 1990-11-26 1992-06-03 Bohuslav Vaclav Kokta Explosionsverfahren zur Papierzellstoffherstellung

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1212505A (en) * 1984-07-17 1986-10-14 Rudy Vit Method, process and apparatus for converting wood, wood residue and or biomass into pulp
CA1230208A (en) * 1987-03-24 1987-12-15 Bohuslav V. Kokta Process for preparing pulp for paper making

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1987001402A1 (en) * 1985-09-03 1987-03-12 Chaudhuri Punya B Method for producing of cellulosic pulp
EP0487793A1 (de) * 1990-11-26 1992-06-03 Bohuslav Vaclav Kokta Explosionsverfahren zur Papierzellstoffherstellung

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EP0501059A1 (de) 1992-09-02
CA2037275A1 (en) 1992-08-29

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