Chromatographic separation and concentration of sulfur dioxide in flue gases

The ability to separate and concentrate SO[sub 2] from a gas stream similar to coal-derived flue gas is accomplished due to the relative adsorption strengths of SO[sub 2] and water on a synthetic mordenite, a phenomenon known as rollup. Laboratory experiments using both simulated and real flue gas are reported which demonstrate the potential of this process. The rollup effect is shown to be influenced by temperature, regeneration conditions, and the feed concentrations of water and SO[sub 2]. Adsorption at higher temperatures (150 vs 50 C) result in less desirable, smaller and broader rollup peaks. Air regeneration at 300 C was found to irreversibly decrease the rollup effect while regeneration with helium at temperatures above 200 C and with air at 150--200 C were found to be optimal. The influence of water was strong with the rollup peak being optimal with 7--8% moisture in the gas. Increasing the feed concentration of SO[sub 2] did not decrease the rollup effect, which implies the use of this phenomenon could be cascaded into a multistage process.