A two-dimensional model for the free-settling regime in continuous thickening
Article first published online: 17 JUN 2004
Copyright © 1990 American Institute of Chemical Engineers
Volume 36, Issue 10, pages 1545–1554, October 1990
How to Cite
Fitch, B. (1990), A two-dimensional model for the free-settling regime in continuous thickening. AIChE J., 36: 1545–1554. doi: 10.1002/aic.690361010
- Issue published online: 17 JUN 2004
- Article first published online: 17 JUN 2004
- Manuscript Revised: 9 AUG 1990
- Manuscript Received: 24 JAN 1990
All classical models for thickening assume one-dimensional continuity. However, the free-settling domain in continuous thickeners is not one-dimensional. Therefore, a two-dimensional model is investigated. The two-dimensional model gives the same values for thickener area demands as the one-dimensional model, but the relationships between batch and steady-state thickening are not the same. Free-settling Kynch characteristics can arise in the continuous operation that do not arise in batch tests. Therefore, design procedures that rely on Kynch theory, such as that of Talmage and Fitch, are not completely valid.
A method is developed, based on extrapolating the Kynch or free-settling segment of a batch settling, curve, that yields an improved prediction for thickener area demand.