Predicting filtration of needle-like crystals: A Monte Carlo simulation study of polydisperse packings of spherocylinders

Abstract

The development of pharmaceutical production processes is frequently hindered by challenging filtration operations. The particle size and shape distribution is known to be a major contributor to filtration performance: here a strategy to understand how this distribution controls the filter cake structure is proposed. We employ Monte Carlo sampling to generate packings/filter cakes of needle-like crystals, a common morphology in the pharmaceutical industry. The cake porosity, particle orientation and size segregation are characterized. The simulations demonstrate the remarkable impact of polydispersity on cake structure and they confirm the influence of particle aspect ratio. Porosity ranges from 40 to 85% in the investigated domain. Porosity increases with increasing polydispersity of the particle length, while polydispersity along the diameter causes the opposite effect. Even though these simulations only account for particle shape and size and neglect flow and particle interactions, they successfully predict the porosity trends of experimental systems of l-Glutamic Acid.