An Experiment Investigation On Dry Character Of Medicine Grain And The Modeling Of A Fluidized-Bed Drying Process

The drying characteristics of a traditional Chinese Medicine"qinghouliyan"granule were studied both in tube-drier and vibrating fluidized bed drier. The fundamental experiment was carried out in the tubular drier. The drying characteristics of the Chinese Medicine pellets were studied there, and the stage of drying was identified as the slow-down period. According to the research of orthogonal drying experiments, the effects of the temperature of drying room,nitrogen humidity and gas velocity on drying velocity were investigated, and the temperature was identified as the most important factor. The model of drying characteristics was established, the tie-in equations of moisture diffusion,heat conductivity and the thin-layer drying pattern were created. Observation indicated that the fitting of equations and curves was rather good, and equation of regression was appropriate.The hydromechanical property of the vibrating fluidized bed was studied, and the effects of vibration and the height of bed on critical gas velocity and pressure drop were studied. The curve of mean drying velocity was obtained, and a series of drying conditions, such as heated air's velocity,temperature,frequency and amplitude of vibration,the height of bed and vacuum were all investigated. The expression of critical fluid-gas velocity and pressure drop of bed were established according to the physical concept, and the result of the experiment can be verified successfully by them.