物料浸没在吸附剂流化床中的冷冻干燥实验

EXPERIMENTAL STUDY ON FREEZE-DRYING BY IMMERSION OF FROZEN PRODUCT IN AN ADSORBENT FLUIDIZED BED

实验研究了将冻结物料浸没在粒状吸附剂流化床中的冷冻干燥过程。结果表明在流化床中充入部分氮气的条件下 ,干燥过程可在常压下进行 ;即使冻结物料温度适度高于其共晶点 ,仍可保持正常的冷冻干燥 ;干燥速率随流化床温度的提高和物料尺寸的减小而加快 ;吸附剂粒径对干燥速率影响不大。与真空冷冻干燥比较 ,这种冷冻干燥方式的设备简单 ,但干燥速率较慢。

The freeze drying processes by immersion of frozen product in an adsorbent fluidized bed are experimentaly studied. The experiments shows that on the ocndition of using certain nitrogen,the process can be operated at atmospheric pressure despite the temperature of frozen product reaching its eutectic point within limits.The drying rate increases with increasing bed temperature and decreasing product size. The influence of adsorbent particle size on drying rate is not obvious. Compared with the vaccum freeze drying,the adsorbent fluidized bed for freeze drying are simpler,howeuor,its drying rate is lower.