IR ABSORPTION CHARACTERISTICS OF AN IR MOISTURE SENSOR AND MECHANISM OF WATER TRANSFER IN FLUIDIZED-BED GRANULATION

Monitoring of moisture content by an infrared (IR) moisture sensor dur ing fluidized bed granulation is a necessary way to control granule gr owth; however, this method requires prior investigation of IR absorpti on characteristics indicating the relationship between granule moistur e content and IR absorption. In this contribution, for a better unders tanding of this IR absorption characteristics, fluidized bed granulati on and drying were conducted at various powder samples and operating c onditions with monitoring of moisture content by an IR moisture sensor . The effects of powder properties such as water absorbing potential a nd diameter on the IR absorption characteristics were investigated exp erimentally. Based on the results obtained, the water transfer mechani sm among particles was analyzed, and factors which determined the IR a bsorption characteristic during fluidized bed granulation and drying w ere discussed.