Brownstock Washing

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    18-Dec-2014

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Descreve os principais conceitos da lavagem da polpa no processo de fabricao de celulose.

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  • 1. Pulp and Paper IndustryBrown Stock Washing
  • 2. Is a mills Soda Loss equal to its Soda Make-up ? YES !! Focus on Soda Loss, not Soda Make-up !
  • 3. Anatomy of Soda Loss100 #Na2SO4/ADT (total mill loss/make-up) 80 #/ADT (BSW loss) 20 #/ADT (spills/purges) Washable Bound Pulp and Power sewers 50#/ADT 30#/ADT- Paper sewer - paper sewer 10#/ADT World Class- Paper sheet - paper sheet 15#/ADT Best Practice 20#/ADT Go find the low hanging fruit
  • 4. Pulp and Power Sewer LossesGood sewer flow and conductivity system w/Alarms on PI or DCS (awareness/training)Food for thought:Establish conductivity round in smaller sewers to find sourcesDregs filter ( 12 to 16 fps Drum superficial velocity Washer Straight, vertical, drop no jogs Dropleg Pulp Recommended Vent Feed ht. > 30 ft. Filtrate Tank Seal Baffle Chamber Vat To Shower Dilution or Effluent EKA of 152 32 CHEMICALSCourtesy April 2005 of Beloit Pulping Pulp Washing TrainingCONFIDENTIAL & TRADE SECRET Technical Marketing & Mill Services
  • 31. Diffuser Efficiency Keys Screen and backflush cycle Pulp and wash water distribution (orifice sizing) Pulp consistency and bed integrity (>10% inlet, 160 F) Production Load (5-6 ADMT/d m2)
  • 32. Screen and Backflush Cycle *Only washing when your extracting Upstroke 10% faster than pulp (proportional valve) Quick closing time of extraction valve and wash valve to minimum position (2-3 sec) (mech stops for wash) Short backflush (