Biogas purification by means of adsorption on pine sawdust-based activated carbon: Impact of water vapor

Humid gas mixtures were then evaluated in the fixed-bed set-up purposely adapted. The effect of water vapor co-adsorption on the separation of CO2 and CH4 was studied for different CO2/CH4 ratios, at 30 °C and atmospheric pressure. Under humid conditions the CO2 uptake was reduced but the CH4 uptake showed negligible influence of water vapor co-adsorption. Results also indicated that the presence of pre-adsorbed water vapor (saturated bed) reduced the capacity of the bed to adsorb CO2 and CH4 but it prompted CO2 adsorption over CH4 and hence facilitated the selectivity towards CO2 with respect to the dry case.