(392m) Computational Fluid Dynamics Simulation of a Carbon Hollow Fiber Membrane Module for IPA/Water Vapor Permeation

We have developed a flexible carbon hollow fiber membranes from sulfonated poly(phenylene oxide) as a carbon precursor. These carbon hollow fiber membranes show excellent performances for gas and vapor separation, and thus efforts have been made to design and develop a membrane module with several hundreds of carbon hollow fibers. In doing that, it has been recognized that module geometries such as number of fibers and packing density of fibers are critical parameters, which influence has to be investigated.

For this purpose, 3D Computational Fluid Dynamics (CFD) simulations of a full-scale carbon hollow fiber membrane module are setup in the present work, analyzing its performance for separation of water and isopropyl alcohol (IPA) mixture in vapor phase. The dimension of membrane module corresponds to the real membrane module (diameter of 15mm, length of 200 mm). Hollow fibers are uniformly distributed along the radial direction with considering several inter-fiber distances (100 to 500 micrometers). The highest packing degree of hollow fibers considered in the simulation corresponds to 1867 fibers at a distance of 100 micrometers. The flow configuration is co-current with the feed on the shell-side. Simulations are performed exploiting the geometrical and physical symmetry. In this configuration, the vapor mixture of IPA and water is progressively enriched of IPA in force of the high permeability of the hollow fiber to water (water permeance of 1x10^-6 mol m^-2 s^-1 Pa^-1, ideal water-IPA separation factor of 5000). In the simulation, the performances of the hollow fiber module are analyzed in terms of purity and recovery of IPA at the retentate. The present investigation allows the separation properties of a hollow fiber module to be evaluated in relation with the radial fiber distribution, which is discussed in detail.