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Published byBathsheba Robinson Modified over 8 years ago
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Broke PPT 210
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What is Broke? Paper that is discarded at any point of the manufacturing and finishing processes inside the paper mill.
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Broke Occurs As trim from wire and winders Reel slab off / other process slab off Off quality paper Breaks
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Broke gets processed Warehoused / Segregated Repulped Deflaked? Broke chest to Blend Chest If it goes to another mill then its recovered paper or secondary fiber
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Wet or Dry Broke Trim is Wet Trim is Wet Saveall is Wet Saveall is Wet Fiber Recovery is Wet Fiber Recovery is Wet Broke after the press is Dry Broke after the press is Dry Size Press Broke – good or bad Size Press Broke – good or bad Reel and Beyond is Dry Reel and Beyond is Dry Others Broke is Dry Others Broke is Dry
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Broke System Uniform and Good Stock Quality Typically 2-4 hours storage capacity Sometimes multiple chest Ability to recirculate Guillotine Cutter Conveyor system or fork/clamp truck
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Broke Pulpers Couch Pit Press(es) Size Press Reel Winder Winder Trim Finishing Room Finishing Room Trim Broke Roll
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Special Treatment Pulpers Coated Broke –White pitch? –May have separate cleaning/screening etc Wet-strength Broke –Time/temperature/chemicals –Special design – Tornado etc
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Broke Usage Determine Broke Balance Determine Broke Balance Steady as She Goes Steady as She Goes At an extended break – use more At an extended break – use more Be careful Be careful Increase in fines and filler Increase in fines and filler Change in system charge Change in system charge Change in retention Change in retention Change in dry/wet line Change in dry/wet line
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Fiber Recovery Systems Remember this is a part of Wet Broke Filtration Flotation Fractionation Sedimentation
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Feed water to Fiber Recovery Wire Pit Overflow Wire Pit Overflow PM Vacuum Boxes PM Vacuum Boxes Tray boxes Tray boxes Broke Thickener Broke Thickener etc etc
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Desired Constant Feed Rate But Variations in retention Variations from sweetener usage Grade Changes Changes in FW supply
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Types of Fiber Recovery Filtration –Disc Filter –Drum Filter Flotation –Bubbles In Hydrocal –DAF Classification –Sidehill Sedimentation settling basins –Usually in wastewater treatment
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Recovered Water Detrimental Substances –Nonionic –Anionic trash Consumes retention aids –Precipitate onto surfaces of fiber/filler/fines Affect bonding Brightness Accessibility of process chemicals
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Composition/Origin of Detrimental Substances Sodium Silicate – peroxide bleaching, deinking, sec. fiber Polyphosphate – filler dispersing agent Polyacrylate – filler dispersing agent Organic acids – pitch dispersing agent Carboxymethycellulose – coated broke Starch – sec. fibers, broke, strength agents Humic acids – fresh water Lignin derivatives – kraft or mechanical pulps Lignosulfonates – sulfite, NSSC, CTMP Hemicellulose – mechanical pulp Fatty acids – mechanical pulp
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Recovered Water Organic Dissolved & Colloidal substances –Nutrients for microbio –Slime and smell –Aerobic micro promotes corrosion Inorganic Dissolved substances –Salts(electrolytes) Corrosion Reduce fiber swelling Measure things like –COD, DOC, TOC, turbidity, zeta, conductivity
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