Mathematical model of drying in a brown coal mill system. 1. Formulation of model

✍ Scribed by Malcolm J. McIntosh

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 607 KB
• Volume: 55
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(76)90069-7

✦ Synopsis

Brown coals, because of their high as-mined moisture contents, are dried as they are transported through the drying system of a power station mill, by hot gas taken from the boiler combustion chamber. In this paper, a mathematical model of the drying process that occurs in this system is developed and tested. In the first part of the paper, drying experiments on single coal particles in hot gas streams are described and a model of the drying of a single particle is developed. From the single-particle study, a rate equation is obtained which is used in the formulation of a model of the mill drying process. The basic assumptions necessary for the development of the drying-process model are discussed. Modifications to a simple model are proposed to account more realistically for gas-particle interactions.

Latrobe Valley brown coals have as-mined moisture contents varying typically between l-5 and 2.3 kg water/kg dry coal. In practice, the coal is both dried and milled prior to introduction into the boiler by passing it through a mill drying