(504c) Mathematical Modeling of Hollow Fiber Gas-Liquid Membrane Contactors for Acid Gas Removal

The removal of acid gases such as CO₂, SO₂ and H₂S from industrial and natural gases is an important separation process. Membrane gas absorption is a well known hybrid approach wherein the advantages of both absorption and membrane processes are combined for cost-effective separation and removal of acid gas components from industrial and natural gases.  Gas Technology Institute (GTI) and PoroGen Corporation are jointly developing novel gas-liquid membrane contactors for CO₂ and H₂S removal. Extensive laboratory and bench-scale measurements are underway at GTI to bring this technology to commercialization. In these membrane contactors, the acid gas stream passes through the hollow fiber membrane tubes while a chemically reactive solvent flow on the shell side of the module. The acid gas components diffuse through the membrane walls and are finally removed in the selective solvent by reactive absorption. A variety of models with increasing complexity are compared for the simulation of the membrane gas absorption process. The tube side flow includes plug flow and parabolic velocity profiles. Flow patterns reflecting plug flow, Happel’s free surface model and random distribution of fiber model are considered for the shell side of the membrane module. Solution methods include analytical and semi-analytical approaches, apart from numerical schemes. The coupled differential equations are solved using an Excel VBA platform combined with Aspen Plus process simulator.