Measurement of moisture content by IR sensor in fluidized bed granulation. Effects of operating variables on the relationship between granule moisture content and absorbance of IR spectra

Abstract

In this study, the validity of moisture measurement by an I R sensor was investigated in fluidized bed granulation. The effects of operating variables on the relationship between granule moisture content and the absorbance of IR spectra were examined experimentally. It was found that the air flow rate of purge air used for preventing powder adhesion, fluidizing air velocity, agitator rotational speed and spray raise size had no effect on the relationship. However, if the dampening speed was extremely low, the effects of fluidization air temperature and liquid flow rate on the relationship could he recognized. This was because the surface drying due to the extremely low dampening speed caused water to transfer from the inside to the surface. As a result, it can be concluded that the measurement of moisture content by an IR moisture sensor can be conducted with high accuracy, free of operating conditions, unless the granulation is conducted under an extremely low dampening speed.