Characterization of a Novel Drying Technology for Continuous Processing of Cohesive Materials: An Ibuprofen Case Study

This work addresses the influence of several process parameters on the performance of a novel drying device (patent NL2020740B1). In the new dryer, the processed substance is conveyed through the grooves of a large rotor via an interlocking screw design. A gentle, forced flow is created, preventing agglomeration and attrition and enabling a new technology of continuous drying for poorly flowing substances, which are often applied in the pharmaceutical industry. Drying test runs are performed using water-wetted ibuprofen, a nonsteroidal anti-inflammatory drug with poor material flow properties. The substances were tested according to their size, shape, and flow properties prior to the test runs. The process parameters in question were the temperature, mass flow, air flow, rotational speed, and initial moisture. Additionally, test runs to estimate the drying mechanism and the long-term process behavior, as well as reprocessing tests of the substance ibuprofen, were executed. It was shown that the dryer's performance for cohesive materials was optimal (continuous process times of up to 10 h were possible with evaporation rates up to 688 g/h). The process was robust, with a few drawbacks related to materials that are prone to tribocharging.