PRES 2 study plan
PRES 2 · Give each week a clear focus.
8 weeks · About 7 hours per week
Pulp mill processes and fiber line
Map the kraft fiber line from chip yard to brownstock washing, labeling each unit operation and its purpose
Trace the cooking chemistry (white liquor, sulfidity, H-factor, kappa number) and explain how each variable shifts pulp quality
Compare continuous and batch cooking sequences and list the equipment differences between them
Draw a block flow diagram of a two-vessel hydraulic digester from memory and annotate the liquor flows
Your checkpoint
One-page annotated fiber line flow diagram plus a 15-term glossary of cooking variables with target ranges
Pulp mill processes and fiber line & Reactor and digester equipment design
Describe oxygen delignification, bleaching stages (D0, Eop, D1, P) and their effluent and corrosion implications
Explain black liquor recovery and how pulping chemistry links to the recovery boiler and digester materials
Identify the principal components of a continuous digester: top separator, cooking zone, extraction screens, wash zone, blow line
Explain the function of the liquor circulation, heaters, and flash tanks in a digester system
Your checkpoint
Written comparison table of batch versus continuous digester equipment with at least 10 rows
Reactor and digester equipment design
Analyze digester shell, cone, and nozzle designs for pressure, thermal cycling, and fatigue loading
Explain the role of internal screens, scallops, and their susceptibility to cracking and plugging
Evaluate design features that control thermal stress during heat-up, cook, and blow
Identify common digester degradation mechanisms and where each occurs on the vessel
Your checkpoint
Annotated digester cross-section sketch marking high-stress and high-corrosion locations with a short justification for each
Materials selection and corrosion
Match alloys (carbon steel, austenitic and duplex stainless, nickel alloys, titanium) to specific pulp mill environments
Explain caustic stress corrosion cracking, chloride SCC, and thiosulfate cracking in white liquor and digester service
Describe weld overlays, cladding, and thermal spray coatings and when each is selected
Explain how corrosion allowances and material selection interact with vessel design life
Your checkpoint
Material selection matrix covering at least 8 pulp mill services with chosen alloy, threat, and rationale
Pressure vessel and piping codes
Recall the scope and structure of ASME Section VIII Division 1 and where the design-by-rule formulas apply
Compute minimum required shell thickness for a cylindrical vessel given design pressure, allowable stress, and joint efficiency
Apply rules for openings and reinforcement, and locate the weld joint efficiency categories
Distinguish Section VIII requirements from ASME B31.3 piping requirements for a mill piping system
Explain design conditions, MAWP, and how they are documented on the nameplate
Your checkpoint
Worked calculation set of 5 problems (thickness, MAWP, opening reinforcement) with steps shown and answers checked
Inspection, testing, and non-destructive examination
Select NDE methods (UT, RT, PT, MT, AET, visual) appropriate to digester shell, welds, and overlay inspection
Explain acceptance criteria concepts and how flaw sizing feeds fitness-for-service decisions
Describe pressure test requirements and when hydrostatic versus pneumatic testing is chosen
Outline an inspection plan with intervals and scope for a digester and its nozzles
Your checkpoint
Inspection plan document for one digester including methods, coverage, intervals, and acceptance basis
Safety systems, relief devices, and risk assessment
Size or verify a pressure relief valve for a given relief scenario and explain the governing equations and assumptions
Identify credible relief scenarios for digesters and accumulators, including blocked outlet and thermal expansion
Explain the elements of a risk assessment (HAZOP, LOPA) and how safeguards are credited
Describe safety instrumented function basics and how interlocks protect digester operations
Your checkpoint
Relief scenario list with a worked sizing calculation for one scenario and stated assumptions
Maintenance, repair, and remaining-life assessment & Pressure vessel and piping codes & Inspection, testing, and non-destructive examination
Apply remaining-life assessment methods including corrosion rate trending and fitness-for-service evaluation
Plan repair and alteration work with the code requirements that govern each
Integrate inspection findings into a remaining-life estimate and inspection interval adjustment
Complete a timed mixed-domain practice set and review every missed item to root cause
Your checkpoint
Remaining-life assessment write-up for a corroded digester section plus a scored practice exam log with error analysis
Milestones
Week 2: Can explain the full fiber line from chips to bleached pulp in 10 minutes without notes, including where each major corrosion threat arises
Week 4: Can state the correct alloy for six given mill services and justify each choice by naming the specific degradation mechanism
Week 5: Scores at least 80% on the self-made thickness and MAWP calculation set with correct units throughout
Week 6: Inspection plan is complete enough that another engineer could execute it without asking clarifying questions
Week 7: Relief valve sizing calculation is dimensionally consistent and the chosen scenario is defensible against alternatives
Week 8: Timed mixed-domain practice score of 75% or better, with every error traced to a specific weak topic and a remediation action