Basics of wood, pulp and paper november 2012


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Basics of wood, pulp and paper november 2012

  1. 1. Wood, pulp and paper1 | [Wood, pulp and paper]
  2. 2. Summary  From Tree to Pulp  From Pulp to Paper  Different kinds of paper  Paper characteristics2 | [Wood, pulp and paper]
  3. 3. Summary  From Tree to Pulp  From Pulp to Paper  Different kinds of paper  Paper characteristics3 | [Wood, pulp and paper]
  4. 4. Wood is use for …….. World production by area - source FAO 2009 More info about the sustainability of the paper industry: | [Wood, pulp and paper]
  5. 5. Wood is used for….by continent100% Production by area by woodfuel sawnwood90% continent - source FAO 2009 87% wood based panels industrial roundwood80% pulp, paper & paperboard70%60% 57% 55% 49% 49%50%40% 38% 34%30% 22% 19%20% 17% 17% 14% 14% 16% 14% 14% 12% 10% 9%10% 7% 7% 8% 8% 5% 6% 6% 3% 1% 0% 1% 0% Europe Asia & Pacific Afrique Latin America & North America Western & Central Asia Caribbean5 | [Wood, pulp and paper]
  6. 6. Which part of a tree does the paper industry use ? Wood left-overs, wood shavings : Construction wood : for pulp and for carpentry, panelling furniture or construction Bark : for energy Sawdust : or compost for panelling or energy6 | [Wood, pulp and paper]
  7. 7. Hardwood and Softwood… hardwoodsoftwood 7 | [Wood, pulp and paper]
  8. 8. Hardwood and Softwood… hardwoodsoftwood 8 | [Wood, pulp and paper]
  9. 9. Chemical composition of wood9 | [Wood, pulp and paper]
  10. 10. Pulp making : practically : Debarking Cutting logs with rotating saws Logs rotated in drum with water Debarked logs10 | [Wood, pulp and paper]
  11. 11. Pulp making : practically : Chipping Chipper Chip Screen Chips Chips Chips!11 | [Wood, pulp and paper]
  12. 12. From Tree to Pulp : Mechanical Pulp 2 Major processes : Mechanical pulp The wood is only mechanically treated (grounded) The yield is about 98%, rests products (barks) are used as fertilizer or for heating 1 ton of wood produces 980kg mechanical pulp All the lignin remains in the pulp12 | [Wood, pulp and paper]
  13. 13. Stonegroundwood process Debarking Bark is used to produce energy (bleaching)Pine Washing logs Grinding water exit of the fibres 13 | [Wood, pulp and paper] rotating stone
  14. 14. From Tree to Pulp : Chemical Pulp Chemical pulp The wood is treated : • mechanically (grounded), • thermally (heated up in boiling water) • chemically All the lignin is removed from the wood The yield is about 50%: With 1 ton of wood, we produce about 500kg chemical pulp14 | [Wood, pulp and paper]
  15. 15. Chemical pulp process chips cooking debarking bleaching washingpine/birch sorting Liqueur de cuisson fraiche Chemical recovery Cooking liquor Causticising steam evaporation production of electricity 15 | [Wood, pulp and paper]
  16. 16. Chemical pulp mill Cooking vessel16 | [Wood, pulp and paper]
  17. 17. Different types of pulp….. Between Mechanical process & Chemical process, we have intermediate processes : TMP and CTMP. These processes only remove part of the lignin, up to the level desired. Trees Trees Trees Trees Secondary fibre Logs Logs Logs Logs Deinking Debarking Debarking Debarking Debarking Washing Grinding Steaming Chemical pre- Chemical Recycled softening cooking Pulp Mechanical Grinding Pulp Grinding Chemical Thermo- Pulp Mechanical Chemi - Pulp Thermo - Mechanical Pulp Wood Free Recycled Wood Containing Papers Papers Papers Light Wood Containing Papers17 | [Wood, pulp and paper]
  18. 18. Under the microscope… Chemical pulp Mechanical pulp Recycled pulp Pine Birch Birch18 | [Wood, pulp and paper]
  19. 19. Different pulp for different kinds of paper 100 % chemical pulp 100% mechanical pulp Strength is higher Less strength Less stiffness  Higher stiffness Less bulk  High bulk Easy to bleach Lower brightness Lower opacity  High opacity Smooth surface Rougher surface Brightness stable with time Trend to yellowing19 | [Wood, pulp and paper]
  20. 20. Bleaching of the pulp Without bleaching, the pulp is brown Therefore, depending on the level of brightness we want to achieve, we need to « bleach » the pulp with chemicals. We can make it step by step with different chemicals : 2nd step 3rd step 4th step20 | [Wood, pulp and paper]
  21. 21. Bleaching of the pulp 1 No  Elemental (Cl2) Chlorine Free 2 No (Cl2)  Total And Chlorine Free No (ClO2)21 | [Wood, pulp and paper]
  22. 22. Summary  From Tree to Pulp  From Pulp to Paper  Different kinds of paper  Paper characteristics22 | [Wood, pulp and paper]
  23. 23. Integrated or not integrated…… Papermills do not always make their own pulp they are so called “non integrated mills” (those who produce their own pulp are … integrated mills); they received the pulp in units with a dryness of around 90%.... PULP PRODUCTION within SFPE ALFELD EHINGEN GRATKORN KIRKNIEMI LANAKEN STOCKSTADT23 | [Wood, pulp and paper]
  24. 24. Just before the paper machine Water Hydrapulper Refining Cleaning & Screening Softwood pulp Dyes/Filler Hardwood pulp Waste Filter System Recycled Water24 | [Wood, pulp and paper]
  25. 25. Pulper25 | [Wood, pulp and paper]
  26. 26. Refining Drawing of a refiner Fibres are cut, frayed and hydrated Admission of the pulp discs Feeding screw Refiner discs Outflow of Refining chamber the pulpSlide 26 | [Wood, pulp and paper]26
  27. 27. Refining Fibres before refining fibers after refining27 | [Wood, pulp and paper]
  28. 28. Cleaning and screening Cleaned pulpPulp entry Pulp entry Rejected material Screened pulp 28 Rejected material | [Wood, pulp and paper]
  29. 29. Just before the paper machine Before the pulp is sent to the papermaking machine various additives are included. Water Papermaking uses a lot of water and this is why mills are built next to rivers. A kilo of paper will use 100 litres of water. The water systems are virtually closed where excess water is continuously recycled. Colouring Optical Brightening Agents are added that react with ultra violet light and give the paper a blue whiteness. Dyers are also added. Binders Both latex and starch are used to keep the fillers bound with the pulp. Starch also adds stiffness. Other additives Anti bacterial, retention aids, pH buffers, …etc Fillers29 | [Wood, pulp and paper]
  30. 30. Fillers Clay Calcium carbonate Talc Titane dioxyde Gypsum Clay30 | [Wood, pulp and paper]
  31. 31. Paper machine Up to 80 km/hour Up to 10 meters wide, 430 meters long Cost: a few hundreds millions € 18 months to be built31 | [Wood, pulp and paper]
  32. 32. Paper machine The function of the paper machine is mainly to remove water32 | [Wood, pulp and paper]
  33. 33. Wire section Moisture Moisture content content 99.9% 80%33 | [Wood, pulp and paper]
  34. 34. Wire section34 | [Wood, pulp and paper]
  35. 35. Forming the web Fourdrinier former Twin wire Twin wire hybrid former Duo former35 | [Wood, pulp and paper]
  36. 36. Press section The water is removed by pressure of the sheet in the nip Press felts water water paperweb about 50% of the water is removed in the press section36 | [Wood, pulp and paper]
  37. 37. Press section37 | [Wood, pulp and paper]
  38. 38. Pre - drying section  The water is removed by evaporation  The moisture content of the paper is around 5-8%  The basis paper is ready to be coated (for coated papers) or sized (for uncoated papers)38 | [Wood, pulp and paper]
  39. 39. Pre drying sectionWatercontent 39 | [Wood, pulp and paper]
  40. 40. Fibrous support Fibrous support + sizing = uncoated paper Fibrous support + (sizing) + coating = coated paper ~ 0.1 mm40 | [Wood, pulp and paper]
  41. 41. Size press Absorption Hydrodynamic pressure Mechanical pressure Split of the starch layer A few g/m²/face is applied; the layer is mainly made of starch41 | [Wood, pulp and paper]
  42. 42. Post - drying section  The water is removed by evaporation  The moisture content of the paper is around 5-8%  The basis paper is ready to be coated (for coated papers) or calendered/rewinded for uncoated papers42 | [Wood, pulp and paper]
  43. 43. Why coating papers ? Uncoated Coated43 | [Wood, pulp and paper]
  44. 44. Why coating papers ? uncoated paper light weight coated high weight coated Print quality improves44 | [Wood, pulp and paper]
  45. 45. Why coating papers ? base paper light weight coated high weight coated More and more coating BRIGHTNESS SMOOTHNESS GLOSS PRINTING QUALITYSlide 45 | [Wood, pulp and paper]45
  46. 46. What is the coating colour made of ? What is coating ? Le couchageis made of Coating Mineral pigments Binders Additives Water (35-45%) + or – coating will lead to different kind of papers : LWC, MWC, modern, classic On-line or Off-line coating Single, double, triple coated46 | [Wood, pulp and paper]
  47. 47. How do we coat ? Blade coating Base paper Coating Blade Coating tank47 | [Wood, pulp and paper]
  48. 48. How do we coat ? Blade coating Scanner Hot air dryer Infra red dryers Hot air dryer Scanner Blade coating heads48 | [Wood, pulp and paper]
  49. 49. Blade coater49 | [Wood, pulp and paper]
  50. 50. Cross section of a coated paper fibres fillers coating50 | [Wood, pulp and paper]
  51. 51. Surface of the coated paper Satin? Gloss? Silk? Matt? Satimat? Demi-mat?51 | [Wood, pulp and paper]
  52. 52. Satin or Mat ? Satin Mat 150x5000x 52 | [Wood, pulp and paper]
  53. 53. Classification of paper surfaces Gloss Satin / Silk Matt 5000xGloss > 70 % 30 - 40 % <15%Smoothness 1500 - 3000 sec 300 - 900 sec 50 - 200 sec Marketing evaluation, no strict rule/norm 53 | [Wood, pulp and paper]
  54. 54. How do me make the surface ? Calendering  Pressure  Temperature  Moisture MAT, BRILLANT, DEMI MAT, SILK, ...  Hardness of the rolls  Number of rolls54 | [Wood, pulp and paper]
  55. 55. Supercalendering Uncalendered Steel Steel Paper Soft Soft Blow rolls to cool sheet and Steel prevent Steel wrinkling in nip The softThe soft rolls rolls can Soft Softare usually be of amade of Reversing nip cotton,synthetic paper or Soft Softcovering synthetic covering Steel Steel Soft Soft Steel Steel Calendered Soft Soft Paper Bottom Bottom driver roll driver roll 55 | [Wood, pulp and paper]
  56. 56. Rewinding56 | [Wood, pulp and paper]
  57. 57. Rewinding Mother Reel Slitting Reels for delivery or Drop 3 sheeting Drop 2 Drop 1 Pos. 1/A Pos. 2/B Pos. 3/C Pos. 4/D Pos. 5/E57 | [Wood, pulp and paper]
  58. 58. Reels packaging58 | [Wood, pulp and paper]
  59. 59. Sheeting59 | [Wood, pulp and paper]
  60. 60. Sheeting60 | [Wood, pulp and paper]
  61. 61. Sheeting - slitting61 | [Wood, pulp and paper]
  62. 62. Sheeting - cutting62 | [Wood, pulp and paper]
  63. 63. Sheets packaging63 | [Wood, pulp and paper]
  64. 64. Summary  From Tree to Pulp  From Pulp to Paper  Different kinds of paper  Paper characteristics64 | [Wood, pulp and paper]
  65. 65. Publication papers & end-uses65 | [Wood, pulp and paper]
  66. 66. Summary  From Tree to Pulp  From Pulp to Paper  Different kinds of paper  Paper characteristics66 | [Wood, pulp and paper]
  67. 67. Grammage (g/m²), Thickness (µm), Bulk (cm³/g) Substance or basis weight : Thickness or Caliper : weight in grams of 1 m² paper Distance between one face of the paper and the other Bulk (cm³/g) = Thickness (µm) / grammage (g/m²)67 | [Wood, pulp and paper]
  68. 68. ISO-brightness (%) and CIE whiteness ISO brightness is a measurement of reflected blue light off the paper surface. This is expressed as a percentage in comparison with an ultimate reference. The ISO standard only measures a portion of the reflected light. The CIE whiteness measures the reflected light of the whole spectrum. For both measures, the higher the value, the brighter or whiter the paper is.68 | [Wood, pulp and paper]
  69. 69. Opacity (%) Opacity is related to the ability of light to pass through paper. The higher the percentage, the more opaque the paper is. Opacity isnt always determined by thickness or weight; a thinner paper may have more opacity than a thicker paper if opacifying agents are used. High Low opacity opacity Opacity (ISO 2471) can be defined as the ratio of reflectance from a paper sheet backed by a perfect black and from a sufficiently thick stack of identical sheets of paper.69 | [Wood, pulp and paper]
  70. 70. Gloss (%) Gloss is an optical phenomenon caused when evaluating the appearance of a surface. The evaluation of gloss describes the capacity of a surface to reflect directed light. The measure can be made on the paper itself (paper gloss) or on a printed area (print gloss). Gloss papers are generally the most calendered and thus the thinnest. Gloss Please note we cannot compare gloss measures made paper according to different norms (Tappi T480 & DIN 54502 are the most common). Gloss paper => smooth => high gloss Mat paper Matt paper => rough => low gloss70 | [Wood, pulp and paper]
  71. 71. Smoothness Bekk. (sec) Known also as “roughness” This method measures how long it takes for a certain amount of air to escape from between the paper surface and a smooth metal disc. The smoother the paper, the less openings there are between paper surface and metal disc, so the longer it will take for the air to escape. The higher the figure is, the rougher the surface is. Mat paper Silk paper71 | [Wood, pulp and paper]
  72. 72. Fiber orientation The paper fibers naturally take up alignment roughly parallel to the direction of travel of the web on the PM : this becomes the grain direction or the Machine Direction (MD). the other direction is called Cross Direction (CD). This influences the strength characteristics of the finished paper.72 | [Wood, pulp and paper]
  73. 73. Grain direction 64 SG 64 x 45 Jumbo-reel 45 64 45 x 64 LG 45 • Long Grain: fibres // long side (LG) : 45 X 64 • Short Grain: fibres // short side (SG) : 64 x 45 The first dimension is by convention always the dimension cross the web73 | [Wood, pulp and paper]
  74. 74. Questions ? Will be happy to answer your technical questions : Françoise Accou +32 492.582.287 francoise.accou@sappi.com74 | [Wood, pulp and paper]