Controllability of Product Moisture Content When Nonscreened Sawdust Is Dried in a Spouted Bed

Abstract

The control of the dried product's moisture content is of importance in the production of fuel pellets. Tests have been made in air and superheated steam in a spouted bed using the outlet temperature of the drying medium as a control parameter of the dried material's moisture content. For superheated steam different settings for the inlet medium temperature are also used. In the moisture content interval of 8–17% wet base there is a linear correlation between the dried material moisture content and the outlet temperature of the drying medium. When drying nonscreened sawdust in a spouted bed it is recommendable to use the outlet temperature of the drying medium as a control parameter of the dried material moisture content. This is independent of the size of the sawdust, whether superheated steam or air is used as a drying medium.

Keywords:

• Biomass
• Drying
• Fluidized
• Product moisture control
• Steam

Acknowledgments

We thank Prof. Bengt Månsson and Dr. Lars Nilsson, Karlstad University, Sweden for valuable comments. We accept full responsibility for all remaining deficiencies. We also thank Jan Ljunglöf, Richard Moren, and Martin Siljehult for valuable help with the experiments.