Water vapour adsorption by a coffee‐based microporous carbon: effect on <scp>CO₂</scp> capture

Abstract

Abstract BACKGROUND Carbon materials are appealing adsorbents for postcombustion CO 2 capture applications. In the present work, the adsorption of H 2 O , which is an abundant component in flue gases, and its influence on the adsorption of CO 2 is evaluated using a microporous carbon. RESULTS The adsorption and desorption isotherms of H 2 O at 12.5, 25, 50, 70 and 85 °C were obtained for relative pressures between 0 and 0.95. The average isosteric heat of adsorption of H 2 O on PPC is 46 kJ mol −1 . The equilibrium of adsorption and desorption of H 2 O on PPC can be reasonably well described by the DJD model over the entire temperature and pressure range evaluated. Breakthrough experiments carried out with synthetic flue gas showed that the adsorption of CO 2 is not hindered by H 2 O at short adsorption times, relevant for the adsorption of CO 2 . Moreover, PPC can be fully regenerated recovering its full adsorption capacity after extended exposure to humid gas. CONCLUSIONS Although the adsorption capacity of CO 2 can be reduced by the coadsorption of H 2 O , this effect only becomes significant at long adsorption times. By appropriately selecting the adsorption time in the cyclic process design the concentration of CO 2 in the adsorbed phase can be maximized. © 2015 Society of Chemical Industry