Influence of So2 on Co2 Capture by Adsorption on Activated Carbon

Carbon capture under post-combustion conditions has been the topic of numerous studies in the last decade. Although exhaust gases have typically different components other than CO2, they are commonly neglected in these studies. The presence sulfur dioxide, for example, tends to interfere in the carbon capture process through different mechanisms. In that sense, the present work aimed to evaluate the effects of SO2 on the CO2 retention capacity by means of dynamic tests and simulations for an activated carbon sample under typical conditions found in the post-combustion environment. Results indicate that SO2 has little influence on the CO2 retention capacity of the carbon in comparison to other adsorbent materials, at typical post-combustion flue gas conditions. The highest typical concentration of SO2 led to a decrease of only 12% in the CO2 capture capacity. Additionally, no evidence of reactions with the material was found and both captured components could be completely desorbed by means of suitable regeneration methods. As a consequence, the use of carbon-based adsorbent could exempt the use of a pre-treatment operation to remove SO2 in carbon capture processes. Results also confirmed that the IAST and Langmuir Extended models are not suitable for determining the adsorption selectivity of systems containing species with strong interactions, such as SO2, since the models do not properly account for the competition for the adsorption sites and the condensation of sulfur dioxide in the pores of the adsorbent.