Temperature vacuum swing adsorption for post-combustion carbon capture with different process configurations

Adsorption carbon capture has emerged as a focal point in addressing current global climate issues. Temperature-vacuum swing adsorption (TVSA) has gained increasing attention due to its high adsorption capacity, CO2 purity, and recovery rate. However, four-bed TVSA process cannot meet the demand for high purity CO2 higher than 99 % in some required industrial areas, such as enhanced oil recovery and production of carbon fuels. To further increase CO2 purity, this work systematically investigates a six-bed TVSA process for CO2 adsorption from dry flue gas using zeolite-based adsorbents, and compares its performance with that of a typical four-bed TVSA system. The results indicate that the six-bed TVSA process can achieve a CO2 purity of up to 99 % and a higher recovery rate higher than 96 %, both of which are about 4 % higher than those of the four-bed TVSA process. In terms of productivity and energy consumption, the proposed six-bed adsorption process has a productivity of 1.108 mol kg−1 h−1 and an energy consumption of 3.035 MJ kg−1, which is comparable to that of four-bed process (2.988 MJ kg−1). This study systematically analyses and optimizes key operational parameters to explore approaches for enhancing process performance. It is determined that superior performance is achieved under the following conditions: cycle time of 3600 s, vacuum pressure of 0.5 bar, adsorption temperature of 298.15 K, and regeneration temperature of 413.15 K. The six-bed TVSA process can serve as an energy-efficient technology, capable of producing high-purity and high-recovery CO2 products, which holds significant potential for industrial applications requiring high-purity CO2.