Lesson 1Brownstock washing principles: dilution, displacement, and counter-current washingCovers dilution and displacement methods, shower and drum functions, and counter-current setups. Stresses washing efficiency, soda loss, filtrate recycling, and effects on evaporators, recovery boiler, and downstream fibre quality in pulp processing.
Dilution and displacement washing mechanismsWashing factor, dilution factor, and soda lossWasher types: drum, DD, pressure, and beltFiltrate segregation and counter-current circuitsEffects on evaporators and recovery boiler loadImpacts on bleaching chemistry and fiber qualityLesson 2Drying section fundamentals: dryer cylinder operation, temperature profiles, runnability factors, and reel windingDescribes dryer cylinder functions, steam and condensate systems, and hood ventilation. Addresses temperature profiles, pocket ventilation, sheet draws, and runnability, concluding with reel winding basics, tension management, and roll formation.
Steam groups, condensate removal, and siphonsCylinder surface temperature and heat transferPocket ventilation and humidity managementSheet draws, threading, and runnability limitsDryness profiles and curl or cockle controlReel winding tension, nip, and hardnessLesson 3Bleaching sequences for wood-free papers: typical chemical stages and objectivesOutlines standard bleaching sequences for wood-free grades, covering oxygen, peroxide, and chlorine-free stages. Clarifies stage goals, selectivity, brightness aims, chemical reactions, and influences on strength, dirt, and environmental burden.
Typical ECF and TCF sequences for wood-free pulpStage objectives: O, D, E, P, and peroxide stagesBrightness development and reversion controlChemical selectivity and fiber strength retentionCarryover limits from washing to bleachingEnvironmental and effluent considerationsLesson 4Overview of kraft pulping and brownstock composition and contaminantsDetails kraft brownstock makeup, residual lignin, extractives, and trapped black liquor. Discusses contaminants, shives, metals, and carryover affecting washing efficiency, bleaching expenses, sheet flaws, and recovery demands.
Kraft cooking reactions and delignification profileTypical brownstock kappa, viscosity, and brightnessOrganic and inorganic contaminants in brownstockImpact of shives and knots on downstream operationsCarryover to washing, bleaching, and recoveryLesson 5Stock preparation: screening, cleaning, blend control (hardwood/softwood) and consistency managementExplains screening, cleaning, refining integration, and hardwood-softwood mixing. Concentrates on consistency regulation, contaminant elimination, fibre separation, and stock prep impacts on formation, strength, and machine runnability.
Coarse and fine screening efficiency targetsCentricleaners and removal of heavy contaminantsHardwood and softwood blend strategiesConsistency control loops and instrumentationRefining location relative to screening stagesEffects on formation, strength, and defectsLesson 6Mass and energy balances across the fiber line: yield, solids flow, steam and condensate flowsBuilds mass and energy balances from brownstock to reel across the fibre line. Encompasses yield, solids and liquor flows, steam and condensate loops, aiding troubleshooting, optimisation, and expense monitoring in operations.
Defining system boundaries and process mappingFiber yield, rejects, and loss accountingSolids, liquor, and filtrate flow balancesSteam, condensate, and heat recovery loopsUsing balances for troubleshooting and auditsLinking balances to cost and KPI trackingLesson 7Approach flow systems: save-alls, blending chest, screens, and chemical additionsExamines approach flow from machine chest to headbox. Includes mixing and blending chests, screens, cleaners, save-alls, and chemical points, highlighting stability, basis weight regulation, and short-circulation cleanliness.
Machine chest, mixing chest, and level controlFan pump function and pressure stabilityApproach flow screening and cleaning stagesSave-all systems and white water recoveryChemical addition strategy and timingBasis weight and dilution control systemsLesson 8Interdependencies: how changes in washing, bleaching, refining, or forming affect downstream moisture, strength and steam demandIllustrates interactions between washing, bleaching, refining, forming, pressing, and drying. Highlights upstream shifts in moisture, strength, porosity, and steam needs, plus diagnosing causes via cross-section information.
Washing carryover effects on bleaching and dryingRefining impacts on drainage, strength, and energyForming quality versus pressing and drying limitsPress dryness and downstream steam consumptionBleaching and strength tradeoffs in final sheetSystematic root cause analysis across the lineLesson 9Forming section fundamentals: headbox hydraulics, slice setting, jet-to-wire ratio, and forming fabricsIntroduces headbox hydraulics, slice aperture, and jet-to-wire ratio. Covers turbulence creation, fibre alignment, forming fabric design, and drainage parts, connecting settings to formation, CD profiles, and two-sidedness.
Headbox types: open, hydraulic, and dilutionHeadbox consistency and turbulence intensitySlice opening, lip profile, and CD controlJet-to-wire ratio and fiber orientation effectsForming fabric design and conditioningDrainage elements and vacuum box settingsLesson 10Pressing and consolidation: nip types, press loading, press felts and water removal mechanismsAddresses press nip varieties, loading methods, and press felt design. Explains water extraction, nip residence time, void volume, and rewet, plus pressing effects on dryness, bulk, strength, and dryer steam requirements.
Single, double, and shoe press configurationsPress loading, line pressure, and nip dwell timePress felts, void volume, and conditioningMechanisms of water removal and rewetPress dryness versus bulk and strength tradeoffsImpacts on dryer steam demand and runnability
