PRES 2 case studies
PRES 2 · Put your knowledge to work in context.
PRES 2 - sometimes written out as Pulp Reactor Engineering Standard 2 - is a professional certification exam aimed at engineers, inspectors, and maintenance specialists who work with pulp mill reactors, digesters, and their associated pressure systems. It is intended for people who already have a grounding in mill operations or mechanical integrity and want formal recognition of their ability to reason across process, equipment, materials, and code requirements rather than in a single narrow specialty. The PRES 2 case studies are 5 cases and about 2,453 words.
1Continuous digester screen DP rise after chip-furnish change
A two-vessel continuous digester produces 1,050 adt/d at Kappa 32. Over nine days the upper cooking-zone screen differential pressure rose from 62 to 148 kPa while lower extraction flow fell 15% at constant white liquor flow and steady blow consistency.
553 words, about 3 min2316L filtrate header pitting in a D0 washer
A D0-stage washer filtrate header, 6-inch schedule 40, 316L, carries 120 m3/h at 80 C, pH 2.5, chloride 650 mg/L, and 200 mg/L residual ClO2. After 18 months, internal inspection finds shallow pitting under a 4-mm-thick deposit and one 4-mm-deep pit in the weld heat-affected zone.
495 words, about 2 min3Batch digester relief valve chattering after a set-pressure increase
2 has a MAWP of 1,100 kPa(g) and a design temperature of 175 C. Its conventional spring-loaded relief valve was reset from 965 to 1,035 kPa(g) after a production increase.
461 words, about 2 min4Remaining life of a thinned white liquor accumulator
White liquor accumulator V-210 is a vertical pressure vessel, 3.6 m inside diameter, design 0.85 MPa(g) at 120 C, SA-516 Gr. 70, original shell thickness 20 mm, full radiography, E = 1.0.
474 words, about 2 min5Crack in a batch digester cone weld after a failed repair
4 is a 40-year-old, 22-mm-thick SA-285-C shell with a 3-mm stainless overlay on the top cone. Design is 1,250 kPa(g) at 175 C; it cycles six times per day between 25 C and 170 C.
470 words, about 2 min