Imaging pharmaceutical fluidised beds by electrical capacitance tomography

Fluidised beds are commonly used in the pharmaceutical industry for batch processing of solid particles, e.g. granulating and drying solid materials and coating compressed tablets. Currently, pharmaceutical fluidised beds are operated by trial-and-error, because of the lack of online tools to monitor the internal behaviour, such as gas-solids distribution, and to measure the operation parameters, such as solids´ moisture and the moisture distribution. While electrical capacitance tomography (ECT) has been used to visualise gas-solids distribution in fluidised beds in the past, this paper presents new developments in ECT for visualising and measuring pharmaceutical fluidised beds. Some test results of drying, granulation and coating processes on lab-scale, semi-scale and production-scale fluidised beds will be given. Future development will also be discussed.