Lesson 1Brownstock washing principles: dilution, displacement, and counter-current washingLooks at dilution and displacement methods, shower and drum workings, and counter-current setups. Stresses washing efficiency, soda loss, filtrate reuse, and effects on evaporators, recovery boiler, and downstream fibre quality.
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 windingCovers dryer cylinder workings, steam and condensate systems, and hood ventilation. Includes temperature profiles, pocket ventilation, sheet draws, and runnability, finishing with reel winding basics, tension control, and roll structure.
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 common bleaching sequences for wood-free grades, with oxygen, peroxide, and chlorine-free stages. Covers stage goals, selectivity, brightness aims, chemical interactions, and impacts on strength, dirt, and environmental load.
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 contaminantsExplains kraft brownstock makeup, leftover lignin, extractives, and trapped black liquor. Deals with contaminants, shives, metals, and carryover that affect washing efficiency, bleaching costs, sheet faults, and recovery load.
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 managementDescribes screening, cleaning, refining links, and hardwood-softwood mixing. Focuses on consistency control, contaminant removal, fibre sorting, and how stock prep affects formation, strength, and runnability on the machine.
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 across the fibre line, from brownstock to reel. Covers yield, solids and liquor flows, steam and condensate circuits, and how balances aid troubleshooting, optimisation, and cost tracking.
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, stressing stability, basis weight control, 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 demandShows links between washing, bleaching, refining, forming, pressing, and drying. Highlights how upstream shifts affect moisture, strength, porosity, and steam demand, and diagnosing root causes with cross-section data.
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 opening, and jet-to-wire ratio. Covers turbulence generation, fibre orientation, forming fabric design, and drainage elements, tying 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 mechanismsCovers press nip types, loading methods, and press felt design. Explains water removal, nip dwell time, void volume, and rewet, and how pressing affects dryness, bulk, strength, and steam demand in drying.
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
