Fluidised bed spray granulation process producing two or more different size distributions

摘要

The process recovers two or more fractions of granules of differing size distribution, from a continuous fluidised bed spray granulator. Classification devices are used to extract the product. The granule residence time in the bed is held constant. At the same time, an area ratio is adjusted, enabling a periodic oscillation of the particle size distribution. This is the area ratio of the time integral of the extraction area (f) of the extractor(s), to the base area (F) of the bed. To increase the amplitude fluctuation between maximum and minimum mean granule diameter, the area ratio f/F is reduced in an interval. Then, maintaining this ratio, the granules are extracted in successive fractions, with differing size distributions. Also claimed is the apparatus for carrying out the above process.