In a continuous digester, wood chips and liquor are continuously fed to, and withdrawn from, a pressure vessel. Continuous cooking offers some distinct advantages over batch cooking, including reduced space requirements, improved cooking control, and improved energy efficiency. Many variations of continuous digester equipment and process conditions have been used. Some digesters are hydraulically filled, while others utilize a vapor phase. This module covers the basic principles of operation of vapor phase continuous digesters.
Learning Objectives
- Describe the advantages of continuous digesters
- Identify the purposes of a continuous digester chip feed system
- Describe how process zones are established in a continuous digester
- Identify the benefits of a vapor phase continuous digester
- Describe the advantages of using an impregnation vessel
- Identify some of the guidelines which maximize the benefits of continuous cooking