流化床喷雾制粒机若干机理的研究

Some Mechanisms in a Fluidized-bed Spray Granulator

研究了流化床喷雾制粒机的起始流化速度、粉粒平稳流化及其控制方法、喷雾制粒机理和骤变失稳现象。指出起始流化速度的实验值远大于理论值,但是可以通过对床层压降的监控,实现平稳流化的操作控制。颗粒以团聚方式长大,而湿骤变失稳是本文流化制粒失效的主要形式。讨论了多种过程参量对制粒和骤变失稳的影响,其结果有助于指导实际生产。

This paper discusses some mechanisms in a fluidizedbed spray granulator, including the gas velocity of initial fluidization, steady fluidization and its control, the mechanism of particle formation, and the quenching of fluidized bed. The experiments show that the actual initial fluidising gas velocity is much larger than calculated value. Thus, a method of measuring the pressure drop of the bed is proposed, by which initial fluidization can be known and steady fluidization can be controlled. The particle growth model in the granulator is agglomeration. Wet quenching is a major reason leading to fluidization failure. The effects of process variables on granulation and quenching are also discussed.