In a continuous digester, wood chips are surrounded by alkaline liquor and "cooked" at high temperature for a couple of hours. This cooking process digests, or breaks down, the lignin, or glue, which holds the cellulose fibers together. This course provides an overview of a continuous digester cooking system. It describes the general flow of fiber through the mill, the difference between batch and continuous cooking, the variables that are important to the cooking process, and the major pieces of equipment in the cooking process.
Learning Objectives
At the end of this module, you will be able to:
- Identify the three main components of wood
- Describe mechanical, chemical and semichemical types of pulping
- Differentiate between batch and continuous cooking
- Describe the major steps involved in cooking
- Identify the process flow of wood chips and chemicals through the continuous cooking process
- Recognize and describe the major chip and process variables involved in cooking