Hetero-aggregation of fluidized nanoparticles and solid-containing aerosol droplets

该项目旨在将不同组成的极小颗粒(纳米颗粒或亚微米颗粒)在流态化床中混合成异质凝聚体，这些颗粒还可以借助含有嵌入固体材料的气溶胶液滴进行包裹或涂层。通过这种方式，将产生具有极细分散组分的二元或三元颗粒复合材料，旨在获得新的和更优异的性能。代替传统的流态化，将使用特殊的喷动床设备，进风口可调。在这类设备中，高速进气射流可以在浸没式冲击器和掺入大颗粒破碎器的辅助下，帮助将聚集和破碎之间的高度动态平衡转移到更小和更强的团聚。亚微米气溶胶将通过一种简单、健壮、易于扩展的新技术来产生。关于团聚体的表征，将发展从2D成像数据重建3D团聚体结构的新方法。在这一框架中，将使用非火焰(即非烧结)原料来确定亚团聚混合的程度并将其推向单独的纳米颗粒。最后，该项目将为分层离散模型奠定基础，该模型即使在初级粒子数量非常多的情况下也可以描述过程动力学和团聚形成。在战略规划方案2289中，特别是关于交叉火焰、高剪切混合、辅助流态化和成像的项目，体现了方法上的合作和技术上的互补。

The project aims at mixing in fluidized bed very small particles (nanoparticles or submicron particles) of different composition to hetero-agglomerates, which may additionally be encapsulated or coated with the help of aerosol droplets that contain embedding solid material. In this way, binary or ternary particulate composites of extremely finely dispersed constituents will be produced, aiming at new and superior properties. Instead of conventional fluidization, special spouted bed equipment with adjustable air inlet will be used for processing. High-velocity air inlet jets, which may be assisted by an immersed impactor and admixed large breaker particles, help to shift the highly dynamic equilibrium between aggregation and breakage towards smaller and stronger agglomerates in this kind of equipment. Submicron aerosol will be generated by a novel technique which is simple, robust and easily scalable. Regarding the characterization of agglomerates, new methods to reconstruct 3D agglomerate structure from 2D imaging data will be developed. In this frame, the level of sub-agglomerate mixing will be identified and pushed towards individual nanoparticles by use of non-flame, i.e. not sintered, raw material. Finally, the project will set ground for hierarchical discrete models that can describe process kinetics and agglomerate formation even with very large number of primary particles. In SPP 2289, methodic cooperation and technical complementarity is seen with, especially, projects on crossing flames, high shear mixing, assisted fluidization, and imaging.