The thermal energy of the hot air is used to evaporate the cooling air and pneumatically convey the dry particles in the system. The contact time between the hot air and the sprayed droplets is only a few seconds, during which the drying is reached and the temperature drops. The dried particles did not reach the temperature of the dry air. This makes dry heat sensitive materials without thermal decomposition.
The turbulence in the centrifugal spray dryer dedicated to protease, which is good for drying, also exposes some particles to elevated temperatures. This sometimes leads to lost activity or modification of additives such as adhesives. Therefore, the test work is to recommend each formula, and the combination of inlet and outlet temperature, need to establish relative powder activity and performance in further processing.