Sean Xu Qi Lin

Abstract Spray drying is the prime process for many years for manufacturing food powders. Dairy powders are one of the main products consumed worldwide. There has been a stream of studies published previously on both modeling the drying characteristics of a single milk droplet and the dryer wide simulations incorporating computational fluid dynamics (CFD). In CFD simulations, large numbers of particles of different sizes need be tracked to represent the size distribution; it is desirable to have an accurate yet simple model for drying of a single droplet, which does not require partial differential equation. Here for the first time, two such models are validated. One model is of the characteristic drying rate curve approach and the other (new) model is of the reaction engineering approach. The model predictions are compared against a very wide range of experimental results including isothermal and time‐varying temperature conditions. © 2005 American Institute of Chemical Engineers AIChE J, 2005

Spray drying is the primary method for manufacturing of food powders from liquids. Optimal design and optimization of spray drying operations at the fundamental level require both modeling of the drying characteristics of a single droplet and dryer wide simulations using computational fluid dynamics (CFD). An accurate yet simple model for drying of a single droplet, which does not require solution of partial differential equation, is ideal input for CFD simulations. The reaction engineering approach (REA) is shown to be appropriate in this regard. It has been successfully used for prediction of skim and whole milk droplet drying behavior under various drying conditions. In this study, an aqueous lactose solution was dried in droplet form and the appropriate REA model parameters obtained. The change of diameter of the droplet during drying was measured experimentally and compared with the model results.