Scale-Up, Optimization, and Control of Industrial Batch Fluidized Bed Dryers Using Multilevel Theoretical Models

Abstract

A range of theoretical models at different levels of complexity has been developed and successfully applied to batch fluidized bed dryers. This includes both standard literature models, such as scaling using the characteristic curve, and newly developed methods, such as the “heat-sum” model, and an incremental model allowing for deep bed effects, which demonstrates a second constant rate period. Interconversion is possible where only limited input data is available; for example, the heat-sum model generates a drying curve from temperature measurements alone. Practical applications include scale-up from R&D pilot plants to full-scale dryers, selection of operating conditions, detection of drying endpoint, and prediction of cycle time. This integrated approach allows the most appropriate level of model to be selected for the required task and available data.

Keywords:

• Drying endpoint
• Exhaust humidity
• Heat-sum model
• Operation
• Product temperature