Post-Doctoral Research Associate
Co-Advised By Dr. Johannes Khinast
Ph.D., National Polytechnic Institute of Toulouse, France, 1998
Agitated Drying Crystals
In several processes, drying is the final step in a series of operations and the product recovered from the dryer is often ready for final packaging. The impact of drying is often ignored and the final quality of the desired product is assumed to be controlled by previous operations such as crystallization or precipitation. However, in several cases, the material properties are tremendously affected by drying. The main goal of this study is to develop a fundamental understanding on how wet granular material behave during drying with shear. Shear stress essentially yields crystal size reduction by attrition or abrasion due to particle-particle or particle-surface (wall, agitator) contacts. On the other hand, large agglomerates can be formed under fast drying conditions. The attrition and agglomeration effects can be undesirable in real systems and can create non-uniform drying conditions.
We are therefore essentially interested in (1) understanding the mechanisms leading to crystal size reduction or enlargement during drying and (2) gaining a knowledge of issues affecting scale-up. Our research involves experimental and numerical studies. Our experimental study consists of developing screening tools to continuously measure moisture content and particle morphology (shape, size and particle size distribution). Moisture and drying rate curves, as well as particle size distributions are available for each test. The numerical study is aimed at matching computational results with experimental results.