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WOOD 120 Pulp and Paper. Paper products. Raw material. Chemical pulp mill. http://w3.upm-kymmene.com/upm/internet/cms/upmmma.nsf/lupGraphics/Botnia_Fray%20Bentos%20mill_1.jpg/$file/Botnia_Fray%20Bentos%20mill_1.jpg. Chemical pulp mill. - PowerPoint PPT Presentation
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WOOD 120
Pulp and Paper
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Raw material Paper products
Chemical pulp mill
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http://w3.upm-kymmene.com/upm/internet/cms/upmmma.nsf/lupGraphics/Botnia_Fray%20Bentos%20mill_1.jpg/$file/Botnia_Fray%20Bentos%20mill_1.jpg
Chemical pulp mill
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http://www.metsopaper.com/paper/MPwGeneral.nsf/WebWID/WTB-061228-2256F-E7612/$File/Total_scope_with_large_text.jpg
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Surface Section through paper sheet
Composition of Paper
Lignin “glues” wood cells together
wood fibers or fiber bundles
Pulping
Mechanical• Uses heat and
mechanical energy• Higher yield• Lower quality
Chemical• Uses heat and
chemical energy• Lower yield• Higher quality
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World Production (2002)(x106 metric tonnes)
• Recovered paper 140.7• Mechanical pulp 34.7• Semi-chemical pulp 8.4• Full chemical pulp 121.8
Kraft 116.5Sulphite 5.3
• Dissolving pulp 2.8• Non-wood fiber pulp 19.8
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http://www.unitedeagle.cn/upimages/20083311435587662.jpg
http://www.partonlumber.com/images/000_0334.jpg
Raw material – wood supplyLogs Chips
www.panoramio.com/photos/original/3042908.jpg
http://www.energysolutionscenter.org/gasirpaper/Images/PaperManfLine.jpg
Pulp and Paper – overview of production stages
http://www.energysolutionscenter.org/gasirpaper/Images/PaperManfLine.jpg
Pulping
http://www.energysolutionscenter.org/gasirpaper/Images/PaperManfLine.jpg
Pulp treatment
http://www.energysolutionscenter.org/gasirpaper/Images/PaperManfLine.jpg
Papermaking
wood fibers or fiber bundles
Mechanical pulping
Mechanical Pulping
• Stone ground wood
• Refiner pulps
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Debarking
Drum debarkers
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http://chempatec-auhorn.com/images/pressurizedmechanicalpulpproduction001_480.jpg
Stone Ground Wood
grinding stone
bolts of wood
hydraulic pistons
pulp slurry
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Stone Ground Wood
Stone Ground Wood
• Raw material – short logs (bolts)
• High yield
• Low quality fibers or fiber bundles
• High energy input
• Pulp suitable for tissues
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Refiner pulping
http://www.tut.fi/optics/aoresearch/dlstrobo/
Pretreatment of chips
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Disc refiner detail
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http://www.triple-r.co.nz/pop/pop_pulp09.html
http://www.globalequip.com/photos/bg_901371.001_2.jpg
Refiner pulping
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http://www.metsopaper.com/paper/MPwFiber.nsf/WebWID/WTB-041123-2256F-3E65B/$File/TMP_blue222.jpg
Multiple refiners in parallel
Refiner pulping
• Raw material – chips
• Lower yield than SGW
• Medium quality fibers or fiber bundles
• High energy input
• Pulp suitable for newsprint
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The “Alphabet Pulps”
• RMPrefiner mechanical pulp
• TMP thermo mechanical pulp
• CTMP chemi thermo mechancial pulp
• SGW stone ground wood
• PGW pressurized ground wood
• NSSC neutral sulfite semi chemical
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wood individual fibers
Chemical pulping
Chemical Pulping
•Sulfate process (Kraft)
•Sulfite process
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Kraft process
Delignifies wood by
• fragmenting lignin into smaller units
• adding chemical groups to increase the lignin’s solubility
Tolerates wide range of species
High strength pulp
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Kraft digester - continuous
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http://www.outokumpu.com/35127.epibrw
http://us.magnetrol.com/Images/Applications/PulpDigester.jpg
Kraft pulping – continuous digester
1. Chips and pulping chemicals
2. Steam
3. Blow valve
4. Gases
5. Pulp
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Pulping
Evaporation
Burning
Washing
Cauticising
Whiteliquor
Wood
PulpBleaching
Bailing &Shipping
Kraft liquor recovery cycle
Greenliquor
Blackliquor
Pulp treatment
• Bleaching / Brightening
• Beating (refining)
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http://www.chmltech.com/pulppaper_files/pulp%20bleaching.jpg
Raw material Paper products
Bleaching vs. Brightening
Bleaching• Continuation of
pulping process• Removal of residual
lignin• More permanent• Applied to chemical
pulps
Brightening• Distinct from pulping
process• Impact chromophoric
structures in lignin• More temporary• Applied to mechanical
pulps
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Bleaching/brightening chemicals
• C chlorine Cl2• D chlorine dioxide ClO2
• O oxygen O2
• Z ozone O3
• P peroxide H2O2
• E alkaline extraction NaOH
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Bleaching/brightening sequences
• Classic
e.g., C E D E D
• Elemental Chlorine Free (ECF)
e.g., D E D E D
• Totally Chlorine Free (TCF)
e.g., O Z E P
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Bleaching Towers
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http://www.andritz.com/cir-pic-pk-ar-2002.jpg
Pulp Beating
• Flattens fibers to produce larger surface area – increases hydrogen bonding between fibers
• Unravels fibers to some degree
• Optimum beating time to achieve best paper properties
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Pulp Beating
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Jordan refiner
Pulp Beating
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Before beating After beating
Internal and external defibrillation take place
Papermaking
Foudrinier machine
- thinner paper sheet
- faster production speed
Cylinder machine
- thicker paper sheet
- slower production speed
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Papermaking
• Foudrinier machine- thinner paper sheet- faster production speed
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Foudrinier papermaking machine
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http://www.risiinfo.com/images/magazine/pp_mag/1102papermaking21A.jpg
Foudrinier - schematic
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http://www.astenjohnson.com/images/images_paper-machine.jpg
Blending of pulp stocks
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http://www.dkimages.com/discover/previews/767/108027.JPG
Foudrinier papermaking machine
Foudrinier – wet-end
Foudrinier - presses
Foudrinier – dry-end
Foudrinier – calendering and winding
Foudrinier – moisture loss in paper
Papermaking
• Cylinder machine- thicker paper sheet- slower production speed
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Cylinder papermaking machine
Cylinder papermaking machine
http://www.zangyeu.com.tw/2007/003.jpg
Schematic of cylinder machine
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Screen rotates
Mold remains fixed
Paper layer forms on screen
Level of pulp stock
Couch roll
vacuum pressure
Fibres in suspension
Cylinder papermaking machine
Dryers