Process Technology of hot gas atomization process for rheological complex liquid feed for production of powders with given properties

本研究项目的目标是设计喷涂工艺，以热气作为辅助流体，从具有复杂流变性的进料中生产粉末材料。工艺设计包括复杂粘性介质破碎实验分析、多尺度过程模拟和热气雾化制粉中试。复杂粘性进料（例如具有粘弹性行为）的雾化在工业应用中非常重要。在常规雾化工艺条件下，具有复杂流变性的液体的破碎可能不完全。这导致产品中的高纤维分数。本课题的目的是利用热气流提高外混式双流体喷嘴的雾化效率。热空气还用于直接干燥喷雾液滴。由此产生的干燥动力学预测应用多尺度模拟。这样就可以分析整体流动和局部流动现象对喷雾传热传质的影响。例如，液滴的局部聚集对单个液滴的干燥行为具有巨大影响。该项目的主要目标是确定性预测的过程框架，其中所需的产品性能（粉末性能）在热气体雾化过程中可以考虑到生产过程的安全性和稳定性。

The object of this reasearch project is the design of spray processes for the production of powder material from feed materials with complex rheology using hot gas as assisting fluid. The process design includes the experimental analysis of the breakup of complex viscous media, the multiscale process simulation and the powder production with the hot-gas atomization process at pilot-scale. The atomization of complex-viscous feed materials (e.g. with viscoelastic behaviour) is of great importance in industrial applications. Under conventional atomization process conditions the breakup of liquids with complex rheology may not be complete. This results in a high fiber fraction within the product. The aim of the project is to enhance the atomization effectivity with the use of hot gas in an external mixing twin-fluid atomizer. The hot air is also used to directly dry the spray droplets. The resulting drying kinetics are predicted applying multiscale simulations. Thus the influence of integral as well as local flow phenomena on the heat and mass transfer in the spray can be analysed. For instance the local clustering of droplets has a huge impact on the drying behaviour of individiual droplets. The main objective of the project is the deterministic prediction of a process frame, wherein the desired product properties (powder properties) within the hot gas atomization process can be produced taking into account the safety and stability of the process.