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Atomization and Sprays

Journal of the International Institutes for Liquid Atomization and Spray Systems

ISSN for PRINT: 1045-5110

Institutional price:	$787.00
Issues per year:	8

Best Paper Award Selection - Editorial Board Site

2008, Volume18

102 pages

Issue price - $118.00

USE OF WATER DEPOSITION TO STUDY THE MAIN FACTORS IN WALL COLLISIONS OF DROPLETS IN A PHARMACEUTICAL-SCALE SPRAY DRYER

T. Lamy
School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, NSW 2006, Australia

N. Collins
School of Chemical and Biomolecular Engineering, University of Sydney, Sydney, NSW 2006, Australia

T. A. G. Langrish
Department of Chemical Engineering, The University of Sydney, Sydney, NSW 2006, Australia

ABSTRACT

Experiments were conducted to investigate the effect of different operating conditions on the process of wall deposition in a Büchi B290 pharmaceutical-type spray dryer, with a drying chamber diameter of 0.155 m and a main chamber height of 0.48 m. In the experiments, liquid flow rates were between 7 and 28 mL/min, airflow rates to the atomizer were between 170 and 670 L/hr, and main airflow rates through the dryer were between 20 and 38 m³ /hr. The results suggested that the droplet concentration is more important than the initial droplet velocity in determining the rates of collision with walls. The collision of cold water droplets was simulated using a mathematical model based on tracking droplet trajectories, and the simulations of the deposition behavior give important guidance in interpreting the deposition mechanisms in the experimental results.