Runling Peng ,Zhan Gao, Haonan Zhai, Jinyue Liu, Wei Wang, Jinjuan Sun, Yunbo Shen
Abstract
For spray freeze-drying (SFD) powder materials, traditional static drying is not conducive to heat and mass transfer due to the accumulation of dried layers, resulting in low drying efficiency and difficulty in large-scale production. In order to improve the drying efficiency of SFD in the preparation nano-powders, a rotary freeze dryer was designed, and the simulation models of the drum and material particles by motion dynamics were constructed. The structural and process parameters of the drum were optimized by the Engineering Data Exchange Model (EDEM) simulation analysis. The results indicate that the optimal dispersion of material particles in the drum was achieved with a shovel plate tilt angle of 5°, 18 shovel plates, and a rotational speed of 33 r/min, yielding a maximum dispersion uniformity rate of the material particles is 94%. When the radian of the discharge blade was set to 7π/36 and the rotational speed to 25 r/min, the discharge rate reached its peak 2.25 kg/s. Furthermore, a 3D-printed drum was used for loading rotation experiment, and a comparison between the experimental and simulation results for the loading rotation of the drum was made. It was found that the simulation results are consistent with the experimental results of the motion state of material particles, and the relative error rate of the discharge rate is 4.16%. This confirms the validity of the simulation model and provides a theoretical foundation for the design of rotary freeze dryer.
Keywords:
Spray freeze-drying, drum, EDEM, numerical simulation, optimal design