EP0413736B1 - Verfahren zur herstellung der mechanischen oder chemiemechanischen papierpulpe - Google Patents

Verfahren zur herstellung der mechanischen oder chemiemechanischen papierpulpe Download PDF

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Publication number
EP0413736B1
EP0413736B1 EP19890905472 EP89905472A EP0413736B1 EP 0413736 B1 EP0413736 B1 EP 0413736B1 EP 19890905472 EP19890905472 EP 19890905472 EP 89905472 A EP89905472 A EP 89905472A EP 0413736 B1 EP0413736 B1 EP 0413736B1
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EP
European Patent Office
Prior art keywords
pulp
ton
kwh
beating
energy consumption
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19890905472
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English (en)
French (fr)
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EP0413736A1 (de
Inventor
Per Ossian Engstrand
Lars-Ake Hammar
Myat Thoung Htun
Rune Lennart Pettersson
Börje Nils SVENSSON
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STFI Skogsindustrins Tekniska Forskningsinstitut AB
Original Assignee
STFI Skogsindustrins Tekniska Forskningsinstitut AB
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Application filed by STFI Skogsindustrins Tekniska Forskningsinstitut AB filed Critical STFI Skogsindustrins Tekniska Forskningsinstitut AB
Priority to AT89905472T priority Critical patent/ATE94596T1/de
Publication of EP0413736A1 publication Critical patent/EP0413736A1/de
Application granted granted Critical
Publication of EP0413736B1 publication Critical patent/EP0413736B1/de
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    • 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
    • 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
    • D21B1/14—Disintegrating in mills
    • D21B1/16—Disintegrating in mills in the presence of chemical agents

Definitions

  • This invention relates to a method of making mechanical and chemi-mechanical papermaking pulp by disintegrating and beating wood material in at least two steps.
  • One object of the invention is to carry out the disintegration and beating in such a manner, that the total energy consumption is substantially reduced, as will be be described in the following.
  • the beating of cellulose-containing material at low pulp concentration is a method, which has been employed since long in order to improve the paperforming properties of the fibres. This applies, however, only to fibres free of lignin or substantially free of lignin, such as fibres produced according to the sulphate or sulphite method.
  • pulps manufactured mechanically such as thermomechanical pulp (TMP) or chemi-mechanical pulp (CTMP)
  • TMP thermomechanical pulp
  • CMP chemi-mechanical pulp
  • beating at low concentration so-called post-refining, was not considered applicable other than as a method for increasing the light-scattering capacity of the pulps and for reducing slightly the fibre length and thereby improving the formation at the making of paper.
  • thermomechanical pulp with fibre-modifying chemicals Experiments have been carried out previously to treat thermomechanical pulp with fibre-modifying chemicals. It was then found, that by treating the defibered pulp with ozone prior to the refining in a two-step process the energy consumption could be lowered by up to 30%. This, however, could be achieved only at the expense of the yield.
  • the wood material in a first step is coarse-disintegrated at a concentration of above 20%.
  • the energy input here shall be at maximum 8oo kWh/ton wood material.
  • the acid groups included in the wood material thereafter shall be neutralized entirely or partially, and the material be diluted with water of a temperature corresponding to the softening temperature of the lignin.
  • the dilution water shall have an ion strength of at maximum 0.05 mole per litre.
  • the coarse-disintegrated material then shall be beaten at a concentration of 1-10% with an energy input of totally a maximum of 500 kWh/ton material.
  • the present invention is based on the idea that there is a relation between the disintegration of the wood material to fibres and the way, in which the energy pulses are transferred to the material, i.e. whether the energy pulses are transferred in liquid phase or steam phase. Attention also is to be paid to the thermal and physical state of the wood material when the energy pulses are being transferred.
  • the energy input in the first coarse-defibering step must be low.
  • the first high concentration step can be at atmospheric pressure or pressurized and be carried out by tearing (shredding), chip pressing, plug screwing (type Impressafiner or PREX) or by defibering in a refiner.
  • the final beating then takes place in one or several steps at low pulp concentration, i.e. at a concentration of 1-10%.
  • the specific edge load is sufficiently low, and that the temperature and chemical environment of the fibre suspension has been adjusted to the softening and swelling state of the wood polymers.
  • the temperature at the beating shall be at least as high as the softening temperature of the stiffest amorphous wood polymer, that the acid groups of the wood polymers substantially are ionized, and that the ion strength of the process water is sufficiently low.
  • the flow sheet according to Fig. 1 illustrates the manufacture of thermomechanical pulp for newsprint.
  • Chips from spruce were steamed in a first step and preheated.
  • the preheated chips then were disintegrated in a pressurized refiner with an energy consumption of 700 kWh/ton.
  • 3 kg NaOh were added in the beating zone of the refiner for neutralizing acid groups included in the wood material.
  • To the defibered material dilution water with a temperature of 80 o C and an ion strength of 2.0 mmole/l was added in order to obtain a pulp concentration of 3%.
  • the pulp then was beaten in five subsequent steps at a specific edge load of 0.3-0.5 ws/m and a total net energy consumption of 150 kWh/ton pulp corresponding to a gross energy consumption of 250 kWh/ton pulp to a freeness of 150 ml CSF and a mean fibre length (PML) of 1.8 mm, i.e. about equal to TMP-pulp manufactured in conventional manner with an energy consumption of 1750 kWh/ton pulp.
  • PML mean fibre length
  • the total energy consumption at the method according to the invention thus, was reduced from 1750 to 950 kWh/ton pulp.
  • TMP The manufacture of TMP according to the invention is compared in Fig. 2, 3 and 4 with TMP manufactured conventionally with single-step refining in twin-disc refiner, which is the least energy consuming TMP-process existing with the present state of art.
  • Fig. 2 shows the tensile index as a function of the electric energy consumption. It appears clearly from the Figure, that the increase in tensile index at a certain electric energy consumption is considerably greater for TMP manufactured according to the invention.
  • Fig. 3 shows the tear index as a function of the tensile index for TMP according to the invention and conventional TMP. It appears that the development of the tear index for the respective TMP is about the same, i.e. at optimation of the low concentration beating according to the invention the fibre cutting and thereby the serious decrease in tear index are substantially entirely avoided, which cutting and decrease occur usually at conventional low concentration beating of mechanical pulps.
  • Fig. 4 shows how the light-scattering coefficient (s) develops at conventional TMP and TMP manufactured according to the invention. It appears that the s-development requires as low an electric energy input as the tensile index development, i.e. the saving of electric energy to a certain s-value is of equal size as the saving of electric energy to a certain tensile index value.
  • This example relates to the manufacture of chemi-mechanical pulp (CTMP or CMP) according to the flow sheet shown in Fig. 5.
  • CMP chemi-mechanical pulp
  • impregnation chemicals which can be sulphites, peroxide, oxygen gas, ozone and/or liquor, can take place prior to the first defibering step, after this step but prior to the final beating, after the final beating, or at combinations of these. In the flow sheet shown the impregnation is carried out prior to the first defibering step.
  • the first defibering step at high concentration is carried out in the same way as in Example 1.
  • the washing step is very essential, so that according to the invention the beating shall take place at low ion strength.
  • the washing therefore, is carried out prior to the final beating. In cases when the chemical treatment is carried out as the last process step, washing takes place even after this step.
  • the final beating takes place in the same way as according to Example 1, but process temperature and chemical environment must be adjusted to the special properties, which the wood polymers have assumed by treatment with impregnation chemicals. It is essential to pay regard to the number of sulphonic acid groups, which have been introduced by possible sulphite treatment. As an increasing amount of sulphonic acid groups reduces the softening temperature of the lignin, the temperature of the process water can be lower than at the manufacture of TMP-pulp according to Example 1. A sufficiently high temperature at the manufacture of CTMP is 40 o C. From a brightness point of view it is advantageous to use the lowest possible temperature. By sodium sulphite treatment both the sulphonic acid groups and the carboxylic acid groups ate ionized from the beginning.
  • the pulp then was beaten with a specific edge load of 0.3-0.5 Ws/m in five subsequent steps with a net energy consumption of 150 kWh/ton corresponding to a gross energy consumption of 250 kWh/ton for obtaining a pulp with a freeness of 250 ml CSF and a mean fibre length (PML) of 1.7 mm, i.e. as a conventionally manufactured CTMP-pulp produced in one step with an energy consumption of 1750 kWh/ton.
  • PML mean fibre length
  • the energy consumption was reduced from the conventional 1750 kWh/ton to 850 kWh/ton.
  • CTMP-pulp obtained compared with conventional CTMP-pulp are shown in Table 2.
  • Table 2 Conventional Invention Energy consumption,kWh/ton 1750 850 CSF ml 250 250 PML, mm - 1.7 Tensile index, kNm/kg 40 40 Tensile stiffness index - 4.6 Stretch at break, % 1.9 1.6 Tear index Nm2/kg 6.7 5.5 Density, kg/m3 420 450 S, m2/kg 43 45 ISO-brightness, % 60 60
  • tensile index is shown as a function of the energy consumption for a CTMP-pulp manufactured according to the invention and for pulp manufactured conventionally. Compared at a certain tensile index, for example 40 kNm/kg, conventional refining consumes about 1750 kWh/ton pulp while at the method according to the invention only about 850 kWh/ton are consumed.
  • the light-scattering coefficient of the CTMP-pulp manufactured according to the invention as a function of the energy consumption is shown in the diagram in Fig. 8 compared with conventionally manufactured pulp. It shows here that according to the invention the energy consumption to a certain light-scattering index is substantially lower.
  • This example relates to the manufacture of highly sulfonated CTMP or CMP, i.e pulp containing more than 4 g of bound sulphur per kg wood material.
  • Chips from spruce were impregnated with a sodium sulphite solution containing about 120 g of sodium sulphite per litre in an amount corresponding to a charge of about 12%.
  • the chips were preheated at a temperature of 140 o C for 10 minutes, whereafter they were coarse-disintegrated with an energy consumption of about 400 kWh/ton wood.
  • the defibration was carried out in a pressurized chip refiner, and the yield obtained was 93-94%.
  • the pulp was beaten in three steps at an edge load of 0.3 to 0.5 Ws/m and a net energy consumption of 100 kWh/ton corresponding to a gross energy consumption of 160 kWh/ton.
  • This embodiment is an example of how in the first step extruders can be used for coarse-disintegrating wood material. According to the example an extruder of the type Bivis was used.
  • Spruce chips were steamed in the usual manner at 100 o C for 10 minutes, whereafter they were fed into a Bivis-machine. At the defibration in the machine 2-3% sodium sulphite solution was charged so that the sulfonation degree of the material amounted to 1.5 g of sulphur per kg wood. The electric energy consumtion was about 400 kWh/ton wood when the material passed through the four compression zones of the twin-screw. After discharge, the fibre material was diluted to about 5% pulp concentration at about 70 o C, whereafter the suspension was pumped to beating in seven steps in a low concentration refiner.
  • the freeness of the pulp was about 250 ml CSF
  • the tensile index was 55 kNm/kg
  • the tear index 6 Nm2/kg at a net energy consumption of 150 kWh/ton and a gross energy consumption of 250 kWh/ton.
  • the total energy consumption for the manufacture of chemi-mechanical pulp (CTMP) to a freeness value of 250 ml CSF by the method according to the invention thus, amounts to 650 kWh/ton, which is to be compared with about 1750 kWh/ton according to the best conventional technique for obtaining the same freeness value.

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  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Wood Science & Technology (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Paper (AREA)

Claims (4)

  1. Verfahren zur mechanischen oder chemischmechanischen Herstellung von Papierpulpe mit niedriger Energiezufuhr durch Zerkleinern und Mahlen von Holzmaterial in mindestens zwei Stufen,
    dadurch gekennzeichnet,
    daß das Material in der ersten Stufe in einer Konzentration von mehr als 20 % mit einer Energiezufuhr von maximal 800 kWh/t des Holzmaterials grob zerkleinert wird,
    daß in den Holzpolymeren enthaltenen Säuregruppen ganz oder teilweise durch Zusatz von NaOH in einer Menge von maximal 9 kg/t neutralisiert werden, daß das Material mit Wasser von einer mit dem Erweichungspunkt des Lignins korrespondierenden Temperatur, d. h. 40 - 95° C, und von einer Ionenkonzentration von maximal 0,05 Mol/l verdünnt wird,
    und daß das Material in einer oder mehreren Stufen bei einer Konzentration von 1 bis 10% mit einem Energieaufwand von insgesamt maximal 500 kWh/t des Materials vermahlen wird.
  2. Verfahren gemäß Anspruch 1,
    dadurch gekennzeichnet,
    daß wenigstens 25 % der gesamten Energiezufuhr bei dem Mahlen aufgewendet werden.
  3. Verfahren gemäß Anspruch 1,
    dadurch gekennzeichnet,
    daß das grobzerkleinerte Material nach der ersten Stufe zur Herabsetzung der Ionenkonzentration gewaschen wird.
  4. Verfahren gemäß einem jeden der vorangehenden Ansprüche,
    dadurch gekennzeichnet,
    daß die Energiezufuhr in jeder der Mahlstufen 50 bis 150 kWh/t Pulpe beträgt.
EP19890905472 1988-05-06 1989-04-05 Verfahren zur herstellung der mechanischen oder chemiemechanischen papierpulpe Expired - Lifetime EP0413736B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89905472T ATE94596T1 (de) 1988-05-06 1989-04-05 Verfahren zur herstellung der mechanischen oder chemiemechanischen papierpulpe.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8801731 1988-05-06
SE8801731A SE461103B (sv) 1988-05-06 1988-05-06 Framstaellning av mekanisk och kemimekanisk massa i tvaa steg

Publications (2)

Publication Number Publication Date
EP0413736A1 EP0413736A1 (de) 1991-02-27
EP0413736B1 true EP0413736B1 (de) 1993-09-15

Family

ID=20372264

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890905472 Expired - Lifetime EP0413736B1 (de) 1988-05-06 1989-04-05 Verfahren zur herstellung der mechanischen oder chemiemechanischen papierpulpe

Country Status (7)

Country Link
EP (1) EP0413736B1 (de)
JP (1) JPH03504256A (de)
CA (1) CA1320067C (de)
DE (1) DE68909231T2 (de)
FI (1) FI91787C (de)
SE (1) SE461103B (de)
WO (1) WO1989010998A1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE9002039D0 (sv) * 1990-06-07 1990-06-07 Svenska Traeforskningsinst Saett att framstaella massa
US5853534A (en) * 1992-12-30 1998-12-29 Sunds Defibrator Industries Ab Method of producing pulp with high yield using a two-stage refining system operating at different temperatures
US6899791B2 (en) 1997-08-08 2005-05-31 Andritz Inc. Method of pretreating lignocellulose fiber-containing material in a pulp refining process
US8734611B2 (en) * 2008-03-12 2014-05-27 Andritz Inc. Medium consistency refining method of pulp and system
SE540961C2 (en) * 2016-05-23 2019-01-29 Holmen Ab Method of providing a paper fibre composition by combining chemical and mechanical pulping

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE409476B (sv) * 1978-02-17 1979-08-20 Sca Development Ab Sett for fraffinering av lignocellulosahaltigt material
JPS564791A (en) * 1979-06-18 1981-01-19 Kogyo Gijutsuin Bleaching of mechanical pulp
CA1246374A (en) * 1983-10-24 1988-12-13 Steve Rowland Two stage high consistency refiner
SE456826B (sv) * 1986-04-18 1988-11-07 Svenska Traeforskningsinst Saett att reducera energikonsumtionen vid raffinering av cellulosahaltigt material

Also Published As

Publication number Publication date
FI91787C (fi) 1994-08-10
CA1320067C (en) 1993-07-13
SE8801731L (sv) 1989-11-07
WO1989010998A1 (en) 1989-11-16
DE68909231D1 (de) 1993-10-21
JPH03504256A (ja) 1991-09-19
SE461103B (sv) 1990-01-08
FI91787B (fi) 1994-04-29
EP0413736A1 (de) 1991-02-27
SE8801731D0 (sv) 1988-05-06
DE68909231T2 (de) 1994-04-28
FI905482A0 (fi) 1990-11-05

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