Study of Adsorbents for the Capture of CO2 in Post-combustion. Contribution of CIEMAT to Module 4 of the CENITCO2 Project

The main goal of CIEMAT within the CENIT-CO2 project has been the development of a process for CO2 capture from combustion flue gases by physical adsorption. In the first stage, screening studies to select promising adsorbents were carried out at laboratory scale, using simplified gas compositions. After that, pilot plant studies were performed using appropriate configurations of promising adsorbents under realistic conditions. CO2 adsorption cyclic capacity of different adsorbents has been studied. Lastly, for the adsorbent selected as most promising, its cyclic efficiency and selectivity for CO2 adsorption in the presence of other gaseous components (SO2, H2O, NO) of the combustion gas has been determined, as well as its performance along multiple sorption-desorption cycles in the presence of simulated combustion gas. None of the studied adsorbents, though being promising since they all have a capture efficiency of about 90%, seem to be susceptible of direct application to CO2 capture by physical adsorption under conditions representative of gases exiting the desulphurization tower of conventional pulverized coal combustion plants. As an alternative, the development of hybrid and regenerable solid sorbents (physical-chemical adsorption) is proposed or the application of new technologies under development such as the electrochemical promotion in capturing CO2. (Author) 33 refs.