Cryogenic CO2 capture using dynamically operated packed beds

In this work a novel post-combustion CO2 capture process concept is proposed and developed, based on cryogenic CO2 freeze-out in dynamically operated packed beds. When feeding a flue gas containing CO2, H2O and inert gases to a previously refrigerated packed bed, an effective separation between CO2, H2O and the permanent gases can be achieved on the basis of differences in dew and sublimation points. Temperature and concentration fronts will develop, which move through the bed with different velocities. H2O and CO2 will condensate and desublimate, respectively, extracting the cold energy stored in the packing and therefore avoiding unacceptable pressure drop or plugging. Great advantage is that both H2O and CO2 can be separated from a flue gas simultaneously, circumventing costly pretreatment steps. Furthermore, no chemical absorbent or elevated pressures are required. Experiments have been carried out and demonstrated that CO2 can be well separated from N2. The process is described by a pseudo-homogeneous 1D model. The resulting simulations show good resemblance with experiments.