Dynamic Simulation of Mechanical Solid-Liquid Separation in Centrifuges

离心机机械固液分离的动态仿真

• 批准号: 238344535
• 负责人: Professor Dr.-Ing. Hermann Nirschl
• 金额: --
• 依托单位: Arbeitsgruppe Verfahrenstechnische Maschinen (VM)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2013
• 资助国家: 德国
• 起止时间: 2012-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/238344535?language=en
• 关键词: Dynamic; Simulation; Mechanical; Solid; Liquid

The following sub-project Dynamic Simulation of Mechanical Solid-Liquid Separation Centrifuges deals with the development of a dynamic process model for flowsheet simulations of the separation behaviour and dewatering in continuous centrifuges. During the first two funding periods, material functions for the settling behaviour, the sediment build-up and solids transport of PVC were experimentally investigated. The investigations for the sediment build-up of PVC show incompressible material behaviour with an approximately constant porosity of the saturated cake. In addition to the laboratory tests for the material, experiments for the stepwise change of process conditions and machine parameters for a lab-decanter centrifuge verify a correlation between transient changes of the separation behaviour and the residence time distribution of the liquid. The results yield in a dynamic process model. The approach connects the separation behaviour, residence time distribution and the solids transport by the screw conveyor system with the material properties. The basis of the modelling is the interconnection of different compartments. This allows the solution of local distributed material properties. Moreover, the presented approach combines the settling behaviour with the sediment transport by correcting the volume of the separation zone by considering the sediment radius. In the third funding period, the dynamic process model will be extended by the dewatering of coarsely-dispersed particles, the consolidation behaviour of flocculated suspensions and the flowsheet simulation for the inter-connection between precipitation and solid-liquid separation. A lab centrifuge is used for determining the kinetics of the dewatering process. The cake transport in the conical part of the machine and the dewatering kinetics reveal in the dynamic process model for dewatering. Flocculated particles exhibit a completely different material behaviour for the sediment build-up. The porosity of the cake depends on the compressive yield stress, which is measured in a lab centrifuge. The experimental investigation reveals in the material function for the compressive yield stress. Furthermore, the conveyability of a saturated cake depends on the shear stress and the yield point. Both are measured in a ring shear tester and are combined with the compressive yield stress in the dynamic process model of flocculated slurries in decanter centrifuges. Cooperation with the group of AG Kind for the flowsheet simulation of precipitation and decanter centrifuge will be exhibit the efficiency of Dyssol. This includes the inter-connection of precipitation and solids-liquid separation by taking a tear stream of the fines into the precipitation reactor into account and. This results in a completely coupled dynamic flowsheet of the overall process.

机械固液分离离心机的以下亚项目的动态模拟涉及开发动态过程模型，用于在连续离心机中分离行为和脱水的流程模拟。在前两个资金期间，实验研究了沉积行为的材料功能，实验研究了沉积物的积聚和固体运输。 PVC沉积物积聚的研究显示出不可压缩的材料行为，并且饱和蛋糕的孔隙率大致恒定。除了对材料的实验室测试外，对实验室 - 驱动器离心机的过程条件和机器参数的逐步更改的实验还验证了分离行为的瞬时变化与液体的停留时间分布之间的相关性。结果在动态过程模型中产生。该方法将螺丝传送带系统的分离行为，停留时间分布和固体传输与材料特性相关联。建模的基础是不同隔室的互连。这允许解决局部分布式材料属性。此外，提出的方法通过考虑沉积物半径来纠正分离区的体积，将沉降行为与沉积物传输结合在一起。在第三个资金期间，动态过程模型将通过脱水的脱水颗粒，絮凝悬浮液的巩固行为以及用于降水与固液分离之间连接的流程图模拟来扩展。实验室离心机用于确定脱水过程的动力学。蛋糕在机器的锥形部分和脱水动力学中的蛋糕运输揭示了用于脱水的动态过程模型。絮凝的颗粒表现出完全不同的材料行为，对于沉积物的积累。蛋糕的孔隙率取决于在实验室离心机中测量的压缩屈服应力。实验研究揭示了压缩屈服应力的材料功能。此外，饱和蛋糕的可传输性取决于剪切应力和屈服点。两者均在环形剪切测试仪中测量，并与Decanter离心机的絮凝浆液动态过程模型中的压缩屈服应力结合。与Ag类型的合作进行降水和decanter离心机的流程图模拟，将展示二氧酚的效率。这包括通过将罚款的撕裂流入降水反应器中，并考虑到降水和固体液体分离的连接。这导致了整个过程的完全耦合的动态流程表。