Drying of calcium carbonate in a batch spouted bed dryer: optimization and kinetics modeling

In the present work, the drying of calcium carbonate in a batch spouted bed dryer with inert particles has been investigated experimentally. The effect of several operating parameters including air temperature (90, 100, and 110 ˚C), air velocity (Ums, 1.2 Ums, and 1.5 Ums), and dry solid mass (5, 10, 20 g) has been studied. The Taguchi method has been applied to determine the optimal parameters and also to reduce the number of required experimental runs. It has been found that the dryer performance was affected by all parameters. It has also been found that drying with 5 g dry solid at a temperature of 100 ˚C and a velocity of 1.2 Ums leads to maximum drying efficiency. Additionally, the effect of air inlet velocity and temperature on the drying kinetics of calcium carbonate has been investigated. Several semi-theoretical models with temperature and velocity dependent parameters have been selected to estimate the drying kinetics. The performance of all fitted models was acceptable but the logarithmic model was the best model in terms of the statistical analysis.