Abstract

The role of homogenization in industrial systems is to provide proper feedstock and product properties to ensure the smooth operation of industrial systems. In this paper, an external recirculation mixing tank with unique construction for the homogenization of stratified liquids is investigated. The main focus of the work is to determine the relationship between tank geometry and dead volumes present in the unit. The unit’s geometry was altered by changing the volume of the tank during experimental work. Residence time based methods were applied for the investigation of the system. For a thorough investigation of the unit, computational fluid dynamics methods were employed in COMSOL Multiphysics to obtain data about the velocity field in the unit. Experimental and modeling data were compared and used to understand the impact of the tank geometry on the flow characteristics of the system, the dead volumes present and thus on the required homogenization time. Optimal tank geometry was chosen for the mixing process to minimize dead volume ratios and to allow more profitable operation. It was observed that the increase in the tank’s volume caused more significant amounts of dead volume to form with an increase in dead volume ratio from 20% to 27% for the smallest and largest geometries respectively. Thus, it was concluded that the geometry with the smallest volume is optimal for mixing since it encompasses the largest ratio of active mixing volumes. The methods provided can be used to analyze and optimize other mixing units in which stratified fluids are to be homogenized.

摘要

均质化在工业系统中的作用是提供适当的原料和产品特性，以确保工业系统的平稳运行。在本文中，研究了一种具有独特结构的外循环混合罐，用于分层液体的均质化。这项工作的主要重点是确定罐几何形状与单元中存在的死体积之间的关系。在实验工作期间通过改变水箱的体积来改变装置的几何形状。应用基于停留时间的方法对系统进行研究。为了对该装置进行深入研究，COMSOL Multiphysics 采用了计算流体动力学方法来获取有关装置中速度场的数据。比较实验和建模数据，并用于了解罐几何形状对系统流动特性、存在的死体积以及所需均质时间的影响。为混合过程选择了最佳的罐几何形状，以最大限度地减少死体积比并允许更有利可图的操作。据观察，罐容积的增加导致形成更大量的死体积，最小和最大几何形状的死体积比分别从 20% 增加到 27%。因此，得出的结论是，具有最小体积的几何形状对于混合来说是最佳的，因为它包含最大比例的有效混合体积。所提供的方法可用于分析和优化其他混合单元，其中分层流体将被均质化。