Optimization of the Design of a Continuous Tumble Mixer

Traditionally, the pharmaceutical industry carries out the majority of its manufacturing operations through batch processes. However, processes of this nature have exhibited high operational costs. As a result, in recent times, the pharmaceutical industry is in the midst of transitioning toward continuous manufacturing with the goal of increasing process efficiency and product quality. In particular, one of the most important manufacturing operations for product preparation is the mixing of granulate material, which is an area that is still not fully understood. Thus in this work, the focus was on the comprehension of granulate material mixing in order to obtain the understanding of this phenomena, and be able to optimize the design of a continuous tumble mixer. To reach these objectives, a batch tumble mixer was studied using a binary mixture through computer simulations with Discrete Element Method (DEM). This software enabled the observation and calculation of particle dynamics and the homogeneity of mixing, while varying different particle characteristics and tumble mixer design. Some particle properties and parameters of interest were: particle density (0.6, 1.0, and 1.6 g/cm³), tumble-particle cohesion (1,500 J/m³ and 30,000 J/m³), particle-particle cohesion (2,500 J/m³ and 50,000 J/m³), volume fill percent (10, 15, 20%), and tumble width (3.0, 3.6, and 4.2 cm). In terms of the homogeneity of mixing, the relative standard deviation (RSD) of the concentration of one of the components â??Particle 1- was utilized as criterion. Federal Drug Administration (FDA) standards were used, but in the case of the sampling methodology, it was adjusted due to system limitations.