Dynamic simulation of technical precipitation processes

沉淀是关联固体过程的重要操作。降水动力学起源于快速主要过程（混合，成核，生长......）的复杂耦合。具有二次加工（附聚、熟化.）以及在很长的时间尺度上不稳定的操作条件。搅拌釜式反应器是工业生产中经常使用的反应器，其湍流、流场和组成都具有不均匀性。因此，数值描述是困难的，不可能在封闭模拟中描述技术降水过程的相关过程时间（分钟或小时）。需要混合方法。因此，本项目的目标是开发一种模拟复杂的技术沉淀过程的新方法，在目前的第二个供资期内，开发了一个混合模块，用于模拟搅拌槽反应器中的沉淀过程。该模型基于房室方法。所描述的复杂系统被描述为集成在框架程序（Dyssol），这是由SPP 1679中的中央项目开发的相互连接的隔间（混合和居住时间隔间）。该方法允许进料入口区域中的初级过程与反应器中的复杂流场或混合条件和次级过程解耦。在第二个资助期内，针对一个操作点进行的实验令人印象深刻地证明了隔室方法的有效性。在第三个资助期内，研究重点是将隔室模型扩展到技术相关工艺操作点的整个宽度。因此，混合室近似为具有可变参数的“横流射流”布置。除了第一个供资期自己的方法外，还考虑了Segets/Peukert小组的方法。对于“横流射流”布置降水实验的数值模型的单独验证，应针对该布置进行PIV和LIF测量。整个混合模型的预测能力将与本体反应器的实验和文献数据进行研究。测试向不同晶体物质的转移。应根据流体动力学考虑，通过选择隔室之间的不同交换流，研究装置尺寸（放大）的影响。通过连接产生的流程图模块“沉降式离心机”（Nirschl组），应证明Dyssol的动力学和性能，用于相互连接的、沉淀量超过的、具有颗粒再循环的动态过程。

Precipitation is an important operation of interconnected solid processes. Precipitation dynamics originate from the complex coupling of fast primary processes (mixing, nucleation, growth...) with secondary processes (agglomeration, ripening, ...) and instationary operating conditions on a wide-stretched timescale. The stirred-tank reactor, which is often used in industrial processes, exhibits inhomogeneity in turbulence, flow field and in the composition. For this reason, numerical description is difficult and depicting relevant process times (minutes or hours) for technical precipitation processes in closed simulations is not possible. Hybrid methods are required. Therefore, the aim of this project is the development of a new methodology for the simulation of complex technical precipitation processes.In the current second funding period a hybrid module for the flow sheet simulation of precipitation in stirred-tank reactors was developed. This model is based on a compartment method. The described complex system is depicted by interconnected compartments (mixing- and residence-time-compartment) integrated in the framework program (Dyssol), which is developed by the central project in SPP 1679. This method allows the decoupling of the primary processes in the area of feed inlet from the complex flow field- or mixing conditions and secondary processes in the reactor. Experiments in the second funding period for one operating point prove impressively the validity of the compartment method.In the third funding period the research is now focused on the extension of the compartment model over the whole width of technical relevant process operating points. The mixing compartment is therefore approximated as a 'Jet in Cross Flow' arrangement with variable parameters. Besides own methods from the first funding period, methods from the group Segets/Peukert are considered for this model. For a separate validation of the numerical model for the 'Jet in Cross Flow' arrangement precipitation experiments, PIV and LIF measurements shall be done for this arrangement. The predictive abilities of the whole hybrid model shall be investigated with experimental and literature data of the bulk-reactor. Transfer to different crystal substances is tested. The influence of the apparatus size (scale up) shall be investigated through the choice of different exchange streams between the compartments based on fluid dynamic considerations. By connecting with the resulting flow sheet module 'decanter centrifuge' (group Nirschl) dynamics and the performance of Dyssol for an interconnected, precipitation-exceeding, dynamic process with recirculation of particles shall be demonstrated.