Modeling acid gas competitive facilitated transport on a spinning disk liquid membrane

Abstract

This analysis is presented to evaluate the feasibility of using a thin alkaline liquid film (dynamic membrane) generated on a spinning disk to separate hydrogen sulfide from carbon dioxide. The analysis accounts for the dynamics of liquid flow, dissolved gas transport, and the reaction in the spinning alkaline film. Simulations show that gas permeation is achievable with practical disk radii, and that the liquid may be recirculated without a separate regeneration process. The flowing liquid film functions as a membrane rather than as a scrubbing medium that must be stripped for recycling. In very thin films, insufficient time is available for transferring carbon dioxide to facilitate its transport via reversible conversion to the bicarbonate ion. The transport of hydrogen sulfide, however, which instantaneously undergoes acid dissociation to the bisulfide ion, is not subject to this limitation. Consequently, both high fluxes and high CO2/H2S permselectivities are predicted in very thin films.