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

作为“技术超细颗粒系统的高特异性多维分馏”优先项目的一部分，该子项目研究了在半连续管式离心机的强离心场中利用几何和材料分离特性分离纳米级颗粒集体。在第一个资助期内，开发了一种方法，可以通过分析离心和计算多维品位效率曲线来分析分离实验。颗粒的沉降系数取决于几何和材料因素，其中包括与考虑流体动力直径相反的几个维度。该方法的应用证明了在大小和密度叠加的情况下，重量和重量的纳米颗粒混合物的分馏。实际确定品位效率曲线的困难在于为分布内的每个测量分离标准分配相对数量或质量的颗粒。为了使用快速、无创的测量方法，我们借助紫外可见光谱技术实现了这方面的测量。该方法能够定量测定分馏颗粒混合物的组成。为了产生有价值的过程监控，采用了UV-VIS流量传感器。结果表明，在分级的情况下，可以在较长的处理时间内以较低的误差预测溢流中的颗粒浓度。在第二个资助期，重点将放在通过离心机的分级效率曲线对工艺分馏进行实验评估。在这里，悬浮液性质和设备的操作条件等参数对分离结果起决定性作用。进一步的目标是执行基于模型的评估，并根据多维分离特征对分离结果进行预测，尽可能减少误差。同时，还可以推导出获得理想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馏，因此计划使用UV-VIS流量传感器实时监测分离动力学。这样做的目的是记录一个稳定的测量信号，从中可以提取有关细馏分的相对颗粒浓度的信息。潜在的，产品质量的负面变化可以通过调整操作条件来应对。最终，该子项目致力于高性能离心机中多维分离过程的实验和基于模型的研究，解决策略的发展以及对发生的物理过程的更好理解。

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.