Thermal swing adsorption for post-combustion carbon dioxide capture

The advantages of post-combustion capture of CO2 based on physical adsorption have been extensively studied in the last years regarding to the economy, environmental compatibility, and process’ efficiency. The industrialization of the process involves the construction of adsorption columns in which adsorption and desorption mass transfer processes occur. Each solid-gas system has particular mass and heat transfer properties. In this study the adsorption and desorption processes in the fly ash zeolite-CO2 system in dynamic conditions was investigated. The breakthrough curves were built in a series of experimental conditions aimed at establishing an optimal temperature of desorption. In the temperature range 50-200 oC, the adsorption capacity at the break point was obtained of 100-115 mg/g. The concentration limit of 5 vol.% CO2 in the exhaust gas stream was reached in 11.3-11.9 minutes. The small change in the adsorption capacities achieved for multiple adsorption-desorption cycles and the minor displacement in the break point determine the applicability of a low thermal swing adsorption process at 50 oC. This low temperature of desorption would increase the total energy efficiency of the process, as the required heat could be provided by waste streams from the electricity production process. Acknowledgements This work was financially supported by the NSF, Ministry of Education and Science of Bulgaria under contract DM17/6.