Dynamic simulation of technical precipitation processes

沉淀是相互关联的固体过程的重要操作。降水动力学源于快速初级过程（混合、成核、生长等）与次级过程（团聚、成熟等）以及在广泛时间尺度上的固定操作条件的复杂耦合。搅拌槽反应器是工业生产中常用的一种反应器，其湍流度、流场和组成均不均匀。由于这个原因，数值描述是困难的，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）是不可能的。需要混合方法。因此，该项目的目的是开发一种新的方法来模拟复杂的技术降水过程。在目前的第二个资助期，开发了用于搅拌槽反应器中沉淀的流板模拟的混合模块。该模型基于隔室法。所描述的复杂系统由框架程序（Dyssol）中集成的相互连接的隔间（混合和驻留时间隔间）来描述，该框架程序由SPP 1679的中心项目开发。该方法允许进料入口区域的初级过程与复杂流场或混合条件和反应器中的二级过程解耦。在第二个资助期对一个工作点进行的实验，令人印象深刻地证明了隔间方法的有效性。在第三个资助期，研究现在集中于在技术相关过程操作点的整个宽度上扩展隔间模型。因此，混合室近似为具有可变参数的“横流射流”布置。除了第一个资助期自己的方法外，该模型还考虑了Segets/Peukert小组的方法。为了对“横流射流”降水实验的数值模型进行单独验证，应该对这种布置进行PIV和LIF测量。整个混合模型的预测能力应结合本体反应器的实验数据和文献数据进行研究。转移到不同的晶体物质进行测试。应根据流体动力学的考虑，通过在隔间之间选择不同的交换流来研究设备尺寸（按比例放大）的影响。通过连接所得到的流程图模块“卧螺离心机”（Nirschl组）动力学和Dyssol的性能，可以演示一个相互连接的、沉淀超过的、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.