CO2 sorption and reaction kinetic performance of K2CO3/AC in low temperature and CO2 concentration

Abstract

Abstract Reducing or removing CO 2 is critical to the confined spaces such as submarines, space-crafts or aircrafts while using solid sorbents has been regarded as a promising method. In this work, K 2 CO 3 loaded on activated carbon (K 2 CO 3 /AC) was developed as a new and regenerable sorbent for CO 2 removing in confined spaces. CO 2 sorption performances of K 2 CO 3 /AC were investigated under different conditions by varying the K 2 CO 3 loadings, CO 2 concentrations, H 2 O concentrations, CO 2 sorption temperatures and water pretreatment durations as well as the purge gas flow rates. The CO 2 sorption capacity and carbonation conversion of K 2 CO 3 /AC decrease with increasing temperature and increase with increasing mole ratio of H 2 O concentration over CO 2 concentration. Sufficient water vapor pretreatment is found to be beneficial to the sorption-enhanced performance. Increasing flow rate will weaken the CO 2 sorption performance. The carbonation kinetics was also investigated with the correlation between the shrinking core model and experimental data. Additionally, the sorbent is proved to be regenerable and stable during 20-cycle CO 2 sorption–desorption experiments. K 2 CO 3 /AC presents high carbonation conversion efficiency, high thermal stability, and low dependency on CO 2 partial pressure. Therefore, it can be considered as a new option for CO 2 removal in confined spaces.