Process-technological fractionation of finest particles based on geometrical and material separation characteristics in a strong centrifugal field

作为优先计划“技术超细颗粒系统的高度特异性多维分级”的一部分，该子项目研究利用半连续管式离心机的强离心场中的几何和材料分离特性来分离纳米级颗粒集合体。在第一个资助期间，开发了一种方法，可以通过分析离心来分析分离实验并计算多维级效率曲线。颗粒的沉降系数取决于几何和材料因素，与考虑流体动力学直径相比，其包括多个维度。该方法的应用在重纳米颗粒和轻纳米颗粒的颗粒混合物的叠加尺寸和密度分级的情况下得到了证明。实际确定等级效率曲线的困难在于将颗粒的相对数量或质量分配给分布内的每个测量的分离标准。为了使用快速且非侵入性的测量方法，这一方面是借助紫外可见光谱来实现的。该方法能够定量测定分级颗粒混合物的组成。为了进行有价值的过程监控，采用了 UV-VIS 流量传感器。结果表明，在分类的情况下，可以在较长的处理时间内以较低的误差对溢流中的颗粒浓度进行预测。在第二个资助期内，重点将放在通过离心机的级效率曲线对过程分级进行实验评估。这里，诸如悬浮液特性和设备的操作条件等参数对于分离结果是决定性的。进一步的目标是根据多维分离特性进行基于模型的评估并对分离结果进行预测，误差尽可能小。同时，可以获得所需分离结果的操作参数的最佳选择。由于处理时间也会影响管式离心机中悬浮液的半连续分级，因此计划使用 UV-VIS 流量传感器实时监测分离动力学。其目的是记录稳定的测量信号，从中可以提取有关细粒部分的相对颗粒浓度的信息。潜在地，可以通过调整操作条件来应对产品质量的负面变化。最终，该子项目致力于对高性能离心机中的多维分离过程进行实验和基于模型的研究，开发解决方案策略并更好地了解正在发生的物理过程。

As part of the priority program "Highly specific multidimensional fractionation of technical ultrafine particle systems", the subproject investigates the separation of nanoscale particle collectives using geometric and material separation characteristics in the strong centrifugal field of a semi-continuous tubular centrifuge. In the first funding period, a method was developed which enables the analysis of a separation experiment by means of analytical centrifugation and the calculation of multi-dimensional grade efficiency curves. The sedimentation coefficient of a particle depends on geometrical as well as material factors, which includes several dimensions in contrast to the consideration of a hydrodynamic diameter. The application of the method was demonstrated in the case of superimposed size and density fractionation of a particle mixture of heavy and light nanoparticles. The difficulty in the practical determination of a grade efficiency curve lies in assigning a relative number or mass of particles to each measured separation criteria within the distribution. With the aim of using fast and non-invasive measuring methods, this aspect was implemented with the aid of UV-VIS spectroscopy. The methodology enabled the quantitative determination of the composition of a fractionated particle mixture. In order to generate a valuable process monitoring, a UV-VIS flow sensor was incorporated. It was shown that in case of classification, a prediction of the particle concentration in the overflow can be made over a longer process time with low error.In the second funding period, the focus will lie on the experimental assessment of the process fractionation via grade efficiency curves of the centrifuge. Here, parameters such as the suspension properties and the operating conditions of the apparatus are decisive for the separation result. A further goal it to carrying out model-based evaluations and making predictions about the separation result, depending on the multidimensional separation characteristics, with as little error as possible. Simultaneously, the optimal choice of operating parameters for a desired separation result can be derived. Since the process time also influences the semi-continuous fractionation of the suspensions in a tubular centrifuge, real-time monitoring of the separation kinetics with the UV-VIS flow sensor is planned. The objective hereby is the recording of a stable measuring signal from which information about the relative particle concentration of the fine fraction can be extracted. Potentially, negative changes in product quality can be reacted to by adjusting the operating conditions. Ultimately, the subproject is working on the experimental and model-based investigation of multidimensional separation processes in high-performance centrifuges, on the development of solution strategies and on gaining a better understanding of the occurring physical processes.