Impact of stage configurations, lean-rich heat exchange and regeneration agents on the energy demand of a multistage fluidized bed TSA CO2 capture process

Abstract

Different process configurations of a multistage fluidized bed process for continuous temperature swing adsorption (TSA) of CO2 are investigated using a thermodynamic equilibrium model. Stage numbers on both adsorber and desorber side are varied with respect to achieve energetic optimum operation of the separation process whereas, steam or CO2 are used as regeneration agents on the desorber side. The results show that the total process energy demand generally decreases with increasing number of stages in the adsorber and desorber. The integration of lean-rich heat exchangers into the TSA process is also investigated and it shows that the energy demand of the whole process can be reduced and that the relative effect of a lean-rich heat exchange increases with increasing number of stages in the TSA system. When using CO2 as regeneration agent, the total energy demand of the TSA process becomes larger compared to a multistage TSA system that is operated with steam as stripping agent. The performed process simulations deliver clear guidelines for the selection of energy efficient configurations of continuous TSA CO2 capture processes.