DOE-National Energy Technology Laboratory, United States
pp. 176 - 179
Keywords: solid sorbent, ab initio thermodynamics, computational modeling
Since the current technologies for capturing CO2 are still too energy intensive, to develop new materials that can capture CO2 reversibly with acceptable energy costs are needed. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials have been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO2 adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO2 capture reactions by the solids of interest, we were able to identify only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. At a given CO2 pressure, the turnover temperature (Tt) of an individual solid capture CO2 reaction is fixed. In order to adjust Tt to fit the practical ΔTo, we demonstrate that by mixing different types of solids it’s possible to shift Tt to the a range of ΔTo.