Fully Resolved CFD Simulation of a Hollow Fibre Membrane Module

Abstract

Membrane processes play an important role in gas separation because they are robust and energy efficient. In the last decades a large number of studies have been carried out on this topic. Most of these studies were experimental, black box modelling or one-dimensional process modelling, but just a few applied Computational Fluid Dynamics (CFD) to have a more detailed look at these processes. In addition to experimental investigation CFD can provide more detailed insights on the local flow, the concentration profiles which influence the equilibrium and the driving force for mass transfer without high costs, and lots of effort. Compared to black box modelling and process simulation CFD can also resolve all three spatial dimensions and this is valuable for the investigation of phenomena which are space dependent, e.g. local mixing in the membranes or concentration polarization. In the current study a new CFD solver was developed. The new solver is based on the open source code OpenFOAM® for CFD modelling of membranes using solution-diffusion mechanism. It was validated and calibrated against processes simulation codes and also experiments. The solver was used for the investigation of a geometrical parameter on the design of hollow fibre membrane modules. The effect of permeate outlet positioning (membrane module flow regime) on the quality of separation of a biogas mixture was carried out.