Fixed-bed adsorption of acid gases on a macroreticular ion-exchange resin

Abstract

The fixed-bed adsorption behavior of sulfur dioxide and carbon dioxide on a macroreticular, styrene-divinylbenzene, anion-exchange resin has been studied. The effects of feed composition, feed flow rate, bed length, and bed temperature on bed performance have been determined experimentally. It has been established that the bed has a low capacity for carbon dioxide, and heat of sorption effects are negligible. In contrast, a high adsorption capacity was observed for sulfur dioxide, with significant heat of sorption effects. At sulfur dioxide loadings typical of flue gases from high sulfur (4 wt. %) coals, a bed capacity of about 1500 bed volumes was obtained. Selectivity for sulfur dioxide over carbon dioxide was also found to be very high, with a separation factor of about 1000. The fixed-bed adsorption process has been modeled with the equilibrium coherence theory of chromatography, using a pseudo-isothermal approach that establishes the effective adsorption temperature from the feed composition. This approach has been used to predict bed behavior for frontal development with binary mixtures, and for elution development. It was found that the method is effective for the frontal case, but has limitations with regard to elution development.