OCC plants convert recycled old corrugated containers into pulp that can be used on paper and board machines to make valuable pulp and paper products. After repulping, the OCC pulp contains some contaminants, such as staples, glass debris, and sand, as well as fiber flakes and bundles that were not separated into individual fibers during repulping. To remove these undesirable materials, the pulp slurry goes through one or more screening processes to remove the contaminants that are larger than fibers, followed by one or more cleaning processes to remove smaller contaminants that have lower or higher densities than pulp fibers. This course describes the high density cleaners which remove large, dense contaminants from the repulped OCC before it reaches other screening and cleaning equipment.
Learning Objectives
At the end of this module, you will be able to:
- Describe the purpose of high density cleaners at OCC plants
- Describe typical high density cleaner installations
- Describe how high density cleaners differ from other forward centrifugal cleaners
- Identify and describe the main components of a high density cleaner
- Describe a typical junk trap dump cycle
- Describe the process flows for HD centrifugal cleaners
- Identify important operating variables for high density cleaners
- List safety hazards and guidelines associated with high density cleaners