EP0500674A1 - Procede de production de pate de cellulose - Google Patents

Procede de production de pate de cellulose

Info

Publication number
EP0500674A1
EP0500674A1 EP19900916835 EP90916835A EP0500674A1 EP 0500674 A1 EP0500674 A1 EP 0500674A1 EP 19900916835 EP19900916835 EP 19900916835 EP 90916835 A EP90916835 A EP 90916835A EP 0500674 A1 EP0500674 A1 EP 0500674A1
Authority
EP
European Patent Office
Prior art keywords
wood
pulp
refining
sodium
stage
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.)
Withdrawn
Application number
EP19900916835
Other languages
German (de)
English (en)
Inventor
Per Engstrand
Lars-Ake Hammar
Birger SJÖGREN
Börje SVENSSON
Myat Htun
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.)
Svenska Traforskningsinstitutet
STFI Skogsindustrins Tekniska Forskningsinstitut AB
Original Assignee
Svenska Traforskningsinstitutet
STFI Skogsindustrins Tekniska Forskningsinstitut AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Svenska Traforskningsinstitutet, STFI Skogsindustrins Tekniska Forskningsinstitut AB filed Critical Svenska Traforskningsinstitutet
Publication of EP0500674A1 publication Critical patent/EP0500674A1/fr
Withdrawn legal-status Critical Current

Links

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
    • 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
    • D21B1/02—Pretreatment of the raw materials by chemical or physical means
    • D21B1/021—Pretreatment of the raw materials by chemical or physical means by chemical means
    • 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

  • the present invention relates to a method of producing mechanical or chemimechanical cellulosic pulp, in par ⁇ ticular paper pulp, with a low energy input, by disin- 5 . tegrating and beating (refining) wood material in at least one stage.
  • An object of the present invention is to effect the disintegration and beating of the wood material in a 0 manner which substantially decreases the total energy consumption, as described in more detail here below.
  • a reduction in energy consumption or an improvement in the paper forming properties of the pulp produced is achieved when applying the present invention to present-day manufacturing processes using high pulp consistencies, and also when applying manufacturing processes at lower pulp consistencies, for instance in accordance with the method of manufacturing mechanical and chemimechanical pulps described in Swedish Patent Application No. 8801731-4, published on November 6, 1989.
  • the beating of cellulosic material at low pulp consis- tencies is a method which has long been used to improve the paper forming properties of the fibres. This, how ⁇ ever, applies solely to lignin-free or substantially lignin-free fibres, such as fibres produced in accor ⁇ dance with the sulphate or sulphite methods.
  • mechanically produced pulps as e.g. thermomechanical pulp (TMP) or chemimechanical pulp (CTMP)
  • TMP thermomechanical pulp
  • CMP chemimechanical pulp
  • Pulp and Paper Magazine of Canada, Vol. 81, No. 6, June 1980, pages 72-80 attempts to reduce the energy consumption of chip refining pro ⁇ Waits.
  • One proposal made in this report is that the 0 chemical environment around the fibres is changed by adding chemicals. It was found that energy consumption could be reduced by 30%, by adding sodium hydroxide, although the total consumption still remained in the region of about 1300 kWh/tonne. A poorer yield was 5 obtained with these tests, however, and the brightness was impaired considerably.
  • thermomechanical pulp with fibre-modifying chemicals. It has been found that the energy consumption can be reduced by at most 30%, when the defibred pulp is treated with ozone in a two-stage method, prior to the refining process. This 5. can only be achieved, however, at the cost of the yield.
  • the energy input can be further reduced by means of the present invention, which is characterized by adding to the wood material prior to the beating process an agent which has the ability to form complexes with polyvalent (2 valences or more) metal ions, particularly calcium ions, so-called com ⁇ plexing (sequestering) agent, so that the content of calcium and polyvalent (2 valences or more) ions in the wood to the major part are replaced by sodium ions.
  • the aim with the ion exchange to sodium form in this manner is to provide as good conditions as possible to obtain elektrolytic swelling by causing charged groups, as e.g. carboxylic and/or sulphonic acid groups, to repel each other. Said swelling contributes to the fact that 5.
  • the fibre material can be delaminated (fibrillated) more easily and leniently at refining and beating.
  • the disintegrating and beating processes are carried out in 0 one and the same stage, wherein a complexing agents and preferably also sodium hydroxide for the purpose of neutralizing released acid groups are added to the wood material, preferably after steaming. Surplus liquor is then pressed from the wood, before beating is com- 5 menced.
  • a complexing agents and preferably also sodium hydroxide for the purpose of neutralizing released acid groups are added to the wood material, preferably after steaming.
  • Surplus liquor is then pressed from the wood, before beating is com- 5 menced.
  • the coarse disin ⁇ tegration and beating processes are carried out in mutually different stages.
  • the complexing agent, and also the preferably added sodium 5 hydroxide can be introduced prior to coarsely dis ⁇ integrating the wood or subsequent thereto. It may be advantageous to effect both additions prior to the coarse disintegration stage, particularly in the case of chemimechanical pulp, and thereafter press excessive 0 liquid from the suspension prior to said coarse disin ⁇ tegration stage.
  • the complexing agent is normally added to the wood material in an amount corresponding to the amount of 5 polyvalent metal ions in the wood material. This amount can correspond to 8-130 mmol per kg of wood, suitably 15-50 mmol per kg of wood. A common amount of poly- valent metal ions in Swedish spruce chips is 20-30 mmol of wood, for instance 25 mmol.
  • the complexing agent will preferably be one in the alkali metal form, and then particularly in the sodium form.
  • a complexing agent in the potassium form can also be used in certain instances with respect to economy, whereas the remain ⁇ ing alkali metal forms would be too expensive in normal operation.
  • the amount of complexing agent required can also be calculated on the basis of the amount of calcium and other polyvalent metal ions present in the wood mate ⁇ rial, and determining the molar quantity of these ions and adding the complexing agent in a quantity corres- ponding to ⁇ 50% of this molar quantity.
  • a suitable range is ⁇ 30%.
  • Substantially equimolar quantities can also be used, of course.
  • the pulp is produced by disintegrating and beating wood material in at least two stages.
  • the material is coarsely disintegrated in the first stage and the acid groups present in the wood polymers are neutralized, either completely or partially, suitably by the addi- tion of sodium hydroxide.
  • the material suspension is thinned preferably with a water at a temperature cor ⁇ responding to the softening temperature of the lignin, i.e. a temperature of 40-95°C valid at a refining fre ⁇ quency of about 1 Hertz.
  • frequencies e-g- around 10 4 Hertz
  • Said thinning water suitably have an ion strength (de ⁇ fined as the total content of cations expressed as mol/1 (litre)) of at most 0.05 mol per litre.
  • the mate- rial is then beaten in one or more stages at a consistency of preferably 1-10% and an energy input which is normally in total at most 500 kWh per tonne of material.
  • the complexing agent is added prior to the beating process and can even be added prior to the first stage.
  • chemimechani ⁇ cal pulp it is preferred to add the complexing agent 5. and also to press surplus liquid from the material suspension prior to coarsely disintegrating the material.
  • the complex ⁇ ing agent is normally added to the suspension between the coarsely disintegrating stage and the first beating 0 stage.
  • the suspension consistency during the coarse disinte ⁇ grating stage will therefore preferably be high, e.g. above 20%. It is also suitable to use a low energy input during the coarse disintegrating stage, e.g. an 0 input of at most 800 kWh per tonne wood material, and the sodium hydroxide is preferably added in an amount which will not appreciably exceed the amount required to neutralize the acid groups present in the wood poly ⁇ mers, at most 225 mmol per kg. _5
  • the complexing agent will preferably be a substance capable of forming complexes with polyvalent metal ions, primarily calcium ions.
  • the complexing agent is preferably used in its alkali metal form, primarily its 0 sodium form, so as to deliver sodium ions to the wood and take-up calcium and other polyvalent metal ions from the wood.
  • Suitable groups of complexing agents and examples of 5 specific complexing agents are given in the following Table: Amines-ethyl amines, imines (carboxylates. phosphona- tes, sulphonates) :
  • Poly-carboxylates (including poly-phosphonate and poly- sulphonate) :
  • FIG. 1 is a flow sheet illustrating an inventive embodiment for producing a pulp of the CTMP-type with high consistency refining as a first stage
  • Figure 2 is a flow sheet illustrating an inventive 5 embodiment for producing pulp of the TMP-type with high consistency refining as the first stage;
  • Figure 3 is a flow sheet which illustrates another inventive embodiment for producing TMP, this embodiment 0 using an extruder as the first disintegrating stage.
  • Figure 4 is a flow sheet illustrating another embodi ⁇ ment according to the invention for producing CTMP, this embodiment using a plug screw as first disinte- 5 grating stage.
  • Figure 5 is a flow sheet illustrating an embodiment similar to that according to figure 4, but for produc ⁇ ing TMP.
  • the flow sheet shown in Figure 1 relates to the produc ⁇ tion of chemithermomechanical pulp.
  • Spruce chips were steamed in a first stage and then impregnated with a solution containing a given quantity of complexing agent, in this instance Na.EDTA 25 mmol/kg wood, corre ⁇ sponding to the amount of polyvalent metal ions present in the wood, of which 20 mmol/kg wood were calcium ions.
  • the solution also contained sodium sulphite corresponding to about 160 mmol/kg wood.
  • the wood material was pressed in a plug screw to a dry content of about 50%.
  • the pulp was then defibred at high pulp consistencies and with an energy consumption of 500 kWh/t, whereafter the suspension of defibred wood material was thinned with water having a temperature of 60°C and an ion strength of 2.0 mmol/1, so as to obtain a pulp consistency of 3%.
  • the pulp was then beaten at this pulp concentration at a specific edge load of 0.5 Ws/m and a net energy consumption of 120 kWh/t corresponding to a gross energy consumption of 200 kWh/t to a freeness of 250 ml CSF and a mean fibre length (PML) of 2.0 mm, i.e. equal to and slightly more respectively than is normal in the conventional manufacture of CTMP with an e ergy con- sumption of 1650 kWh/t.
  • PML mean fibre length
  • FIG. 2 is a flow chart which illustrates the manufac ⁇ ture of TMP for use in newsprint.
  • Spruce chips are steamed in a first stage, whereafter the chips are impregnated, preheated and coarsley refined while adding 100 mmol NaOH/kg wood (corresponding to the content of acid groups having protonic form in the wood) at a pulp concentration of 35% in a pressurized refiner with an energy consumption of 600 kWh/t.
  • the coarsely refined pulp stock was then thinned to a pulp concentration of 10% with a solution, temperature 80°C, containing a complexing agent, in the present case
  • Na.EDTA 25 mmol/kg wood, in an amount corresponding to the amount of polyvalent metal ions present in the - wood, in the illustrated case 25 mmol/kg wood, of which 20 mmol/kg wood were calcium ions.
  • the wood material was pressed in a pulp press to a dry content of about 40%.
  • the defibred pulp stock was then thinned with water at a temperature of 80°C and an ion strength of 2.0 mmol/1 to obtain a pulp concentration of 3%.
  • the pulp was then beaten at this pulp concentration at a specific edge load of 0.5 s/m and a net energy con ⁇ sumption of 150 kWh/t, corresponding to a gross energy consumption of 250 kWh/t, to a freeness of 150 ml CSF and a mean fibre length (PML) of 2.0 mm, i.e. respectively equal to and slightly more than is normal in the case of TMP which can be produced in the least energy requiring technique known at present with an energy consumption of 1650 kWh/t (single stage refining with double disc refiners) .
  • Two stage proces ⁇ ses which are at present the most common processes used in the manufacture of TMP, often require an energy input of more than 2000 kWh/t in order to obtain a pulp having a freeness of 150 ml CSF.
  • the inventive 5. method was effective in reducing energy consumption from the level of 1650 kWh/t required in the conven ⁇ tional process to a level of 850 kWh/t, which is also slightly lower than the level achieved with the method taught by the aforementioned Swedish Patent Application No. 8801731-4, in which similar tecnique is used but where no ion exchange takes place with the aid of complexing agents.
  • the flow sheet in Figure 3 illustrates a method of manufacture of TMP for use as newsprint. Spruce chips were steamed in a first stage and then charged to a BiVis-machine.
  • the water had a temperature of 80°C and an ion strength of 2.0 mmol/1.
  • the pulp was then beaten at this pulp concent- ration at a specific edge load of 0.5 Ws/m and a net energy consumption of 200 kWh/t, corresponding to a gross energy consumption of 330 kWh/t to a freeness of 150 ml CSF and a mean fibre length (PML) of 2.0 mm.
  • de- fibring and refining of the pulp required a total electrical energy input of 630 kWh/t, which is lower than that achieved in the preceding Example (Example 2) with TMP, where the energy consumed in achieving a freeness of 150 ml CSF was 850 kWh/t.
  • the flow sheet in Figure 4 illustrates the manufacture of chemithermomechanical pulp while using a complexing agent for the exchange of calcium and other polyvalent ions to sodium ions acting as counterions to the acid groups present in the wood.
  • Spruce chips were steamed in a first stage and then impregnated with a solution containing a quantity of complexing agents, in the illustrated case Na.EDTA 25 mmol/kg wood, corresponding to the polyvalent metalion content of the wood, in this case 25 mmol/kg wood, of which 20 mmol/kg wood were calcium ions.
  • the solution also contains sodium sulphite, in an amount corresponding about 150 mmol/kg wood.
  • the chips were pressed in a plug screw to a dry content of about 50%.
  • the pulp was then preheated and refined at a high pulp concentration in one stage to CSF-levels between 200 and 700 ml CSF with a specific electrical energy consumption which was about 20% lower than that obtained in the absence of ion exchange with the aid of complexing agents.
  • the tensile strength of the pulps in the CSF-range examined was more than 20% greater than when not using complexing agents for ion exchange to sodium form.
  • the pulp was refined in one stage to 500 ml CSF and then in a second stage to 200 ml CSF at a pulp consis ⁇ tency of 30%, slightly more electrical energy was con ⁇ sumed than in the aforementioned case, although the 5. energy consumption was still about 20% lower than the energy consumed with a corresponding reference where no ion exchange was effected where no ion exchange was effected with the aid of complexing agents.
  • the flow sheet in Figure 5 illustrates a method of manufacturing TMP for use in the production of news ⁇ print, while using complexing agents to exchange cal- cium ions and other polyvalent ions to sodium ions acting as counter ions to the acid groups present in the wood.
  • Spruce chips were steamed in a first stage and then impregnated by pressing the chips in a plug screw and allowing the chips to expand in an impregnation vessel containing a solution of complexing agents, in the present case Na.EDTA 25 mmol/kg wood, in an amount cor ⁇ responding to the polyvalent metal-ion content of the wood, in the present case 25 mmol/kg wood, of which

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

Abstract

On produit de la pâte de cellulose mécanique et chimico-mécanique, notamment de la pâte à papier, à une entrée de faible énergie, par désintégration et trituration de matière ligneuse en une ou en plusieurs étapes. Selon l'invention, on ajoute une substance capable de former des complexes avec des ions métal polyvalents, notamment des ions calcium, appelée agent de transformation en complexe, à la matière ligneuse, avant le procédé de trituration, afin de remplacer lesdits ions calcium ou autre métal singulier polyvalent par des ions sodium, ce qui permet de réduire davantage l'entrée d'énergie.
EP19900916835 1989-11-06 1990-11-06 Procede de production de pate de cellulose Withdrawn EP0500674A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8903710A SE8903710D0 (sv) 1989-11-06 1989-11-06 Saett att framstaella cellulosahaltig massa
SE8903710 1989-11-06

Publications (1)

Publication Number Publication Date
EP0500674A1 true EP0500674A1 (fr) 1992-09-02

Family

ID=20377391

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900916835 Withdrawn EP0500674A1 (fr) 1989-11-06 1990-11-06 Procede de production de pate de cellulose

Country Status (8)

Country Link
EP (1) EP0500674A1 (fr)
JP (1) JPH05503965A (fr)
AU (1) AU638511B2 (fr)
BR (1) BR9007815A (fr)
CA (1) CA2073048A1 (fr)
FI (1) FI922025A (fr)
SE (1) SE8903710D0 (fr)
WO (1) WO1991006700A1 (fr)

Families Citing this family (7)

* 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
SE0203673D0 (sv) * 2002-12-12 2002-12-12 Skogsind Tekn Foskningsinst Method for treatment of pulp
FI120651B (fi) * 2007-04-30 2010-01-15 Linde Ag Menetelmä energiankulutuksen vähentämiseksi massasuspension jauhatuksessa paperinvalmistusprosessissa
US8282773B2 (en) 2007-12-14 2012-10-09 Andritz Inc. Method and system to enhance fiber development by addition of treatment agent during mechanical pulping
US8293696B2 (en) 2009-02-06 2012-10-23 Ecolab, Inc. Alkaline composition comprising a chelant mixture, including HEIDA, and method of producing same
SE537483C2 (sv) * 2012-03-23 2015-05-19 Valmet Oy Förfarande och anordning för rengöring av lignocellulosamaterial under impregnering
FI127062B (en) * 2014-11-18 2017-10-31 Upm Kymmene Corp Method and apparatus for mass production

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE416481B (sv) * 1977-05-02 1981-01-05 Mo Och Domsjoe Ab Fofarande och anordning for behandling av vedflis for avlegsnande av tungmetaller och harts
GB1581591A (en) * 1977-05-17 1980-12-17 Hsc Widney Eng Ltd Stay devices for use in roof hatch or roof ventilator assemblies for vehicles

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9106700A1 *

Also Published As

Publication number Publication date
FI922025A0 (fi) 1992-05-05
AU638511B2 (en) 1993-07-01
WO1991006700A1 (fr) 1991-05-16
FI922025A (fi) 1992-05-05
JPH05503965A (ja) 1993-06-24
CA2073048A1 (fr) 1991-05-07
SE8903710D0 (sv) 1989-11-06
BR9007815A (pt) 1992-08-25
AU6720590A (en) 1991-05-31

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