喷雾流化床内干燥主导的颗粒包覆和团聚竞争机理研究

喷雾流化床能实现包覆和团聚颗粒成形，被广泛用于制药、农业、食品、粉末催化剂和化妆品等领域。然而，面向“小粒径、宽分布、严温控”喷雾流化床颗粒成形面临产品质量一致性差的技术瓶颈。针对其背后流态化、喷雾和干燥难以高效协同的科学问题，本项目拟以喷雾流化床内颗粒碰撞特性与喷雾特性的颗粒追踪测速PTV和诱导荧光联合实验测量为支撑，通过蒙特卡罗方法和群平衡模型与CFD-DEM的多层次耦合，构建描述液滴-颗粒-气体相间动量、热量和质量传递的多尺度数值仿真新方法，预测颗粒包覆层和聚团结构微观演变，揭示液滴作用方式，团聚与破碎规律和流化气体干燥潜能与主导成形机制的动态联系规律，综合颗粒成形实验和产品结构表征，阐明包覆和团聚的竞争机理，制定与流态化、喷雾和干燥过程参数关联的高效动态调控策略，以实现喷雾流化床颗粒成形产品质量升级的目标，对面向“中国制造2025”的颗粒成形工业智能化具有重要的学术意义和引领作用。

The particle formation process, including coating (or layering granulation) and agglomeration, can be achieved in spray fluidized beds, which have been widely applied in pharmaceutics, agriculture, foods, powder catalyst and cosmetics industries. But the formation of particles with small size, wide size distribution, and strict temperature range is always facing the technical bottleneck of the low uniformity of product quality, which is associated with the scientific problem of efficient collaboration of fluidization, spray and drying. Based on the particle collision dynamics and spray characteristics obtained from the combined PTV and induced fluorescence measurement, CFD-DEM is coupled with Monte Carlo and population balance modeling in different levels to develop a new multi-scale numerical approach to simulate the momentum, heat and mass transport between droplets, particles, and the fluidization gas. The new approach can directly predict the micro-scale morphology of coating and agglomeration products. The inherent relation between key phase interaction parameters, including the effects of liquid droplets, the law of agglomeration and breakage, and the drying potential of the fluidization gas, and the dominated formation mechanism are comprehensively studied. Together with the characterization of particulate products, the competition mechanism of particle coating and agglomeration is clarified. The dynamic control strategy, relying on the fluidization, spray, and drying operation conditions, is made to finally achieve the goal of updating particulate product quality in spray fluidized beds. To practice the industrial intelligence of particle formation required in “Made in China 2025”, this project has great academic significance and leading influence.