Hydropulper & Repulping Masterclass — Amirkabir Paper Professional Series
This course is designed for process engineers, production supervisors, maintenance leads, quality managers, and technical trainers working in stock preparation, recycling and papermaking operations. It assumes basic knowledge of papermaking concepts but provides practical, industry-grade guidance for front-line and engineering staff.
Recovered-fiber processing is the most variable and risk-prone area in modern mills. Proper pulper selection, contaminant control, and preventive maintenance directly affect energy consumption, throughput stability, product quality, and operating cost. This course consolidates operational best practices, troubleshooting frameworks, and evidence-based protocols to reduce downtime, protect equipment, and increase yield.
The course is modular and progressive: Module 0 (this module) sets expectations and terminology; Module 1 covers hydropulper fundamentals and operations; Modules 2–6 address waste characterization, deinking, screening, problem grades, utilities & sustainability; Module 7 focuses on KPIs, certification and continuing development. Each lesson includes an integrated checklist, applied examples, and assessment items.
Assessments emphasize applied understanding and calculation accuracy. Theory assessments are text-based and graded against objective rubrics. Successful completion yields a certification recognizing competency in hydropulper operations and stock preparation.
Practical instructions to navigate content, complete lessons, and prepare for assessments.
Each lesson contains:
The course draws upon industry reference texts and manufacturer best-practices. Downloadable resources provided in each lesson include:
Learners must:
Key definitions and quick-reference terms used throughout the course.
Each term is defined with industrial context and a short note on relevance to pulping and stock preparation.
| Term | Definition |
|---|---|
| Attrition | Mechanical action that breaks fiber bundles and removes attached contaminants; high attrition increases fiber damage risk. |
| Broke | Rejected web or trim from paper machines reused in repulping operations. |
| Consistency (Concentration) | Mass fraction of dry fiber in pulp suspension (expressed as %). Critical for pulping and screening behavior. |
| Deinking | Chemical and mechanical processes to detach and remove printing ink from fibers, often using flotation. |
| Hydropulper | Vessel with rotor/impeller that produces fiber suspension from waste paper through mechanical agitation and controlled chemistry. |
| Junker | Screw-based reject conveyor and separator for heavy contaminants removed from pulpers. |
| Ragger | Device that continuously extracts long ropes and non-fiber trash from pulpers to prevent downstream damage. |
| Stickies | Tackifying contaminants (hot-melt adhesives, pressure sensitive adhesives, waxes) that agglomerate and deposit on papermaking equipment. |
| Tip Speed | Linear speed at the impeller/trailing edge of rotor (m/s). Strongly influences impact energy and defibering. |
| Wet-strength | Paper treated with resins (e.g., PAE, AKD combinations) to retain strength when wet; difficult to repulp. |
| Vibrating Screen | Mechanical screen that uses vibration to separate larger contaminants from pulp suspension. |
| Yield | Mass of usable fiber produced per mass of input raw material, expressed as percentage. |
| De-fibered Clumps | Partially disintegrated bundles that pass through initial pulping but require additional attrition to separate. |
| Flotation | Deinking process using air bubbles and surfactants to remove hydrophobic ink particles to the foam layer. |
| Coarse Screen | Initial screening stage to remove large trash such as plastics, ropes and flakes. |
| Cleaning Train | Series of centrifugal cleaners and hydrocyclones to remove heavy and dense contaminants. |