MOF and UiO-67/MCM-41 adsorbents for pre-combustion CO₂ capture by PSA: Breakthrough experiments and process design

Two new MOF materials, i.e. USO-2-Ni MOF and UiO-67/MCM-41 hybrid, are evaluated as regards their potential for pre-combustion CO₂ capture within an IGCC power plant. Both materials have been formulated as particles, thus allowing for a meaningful characterization in view of process scale-up. This is done by first conducting fixed bed experiments, where the adsorbent material is packed into a column and exposed to three different CO₂/H₂ mixtures at a given temperature (25 °C) and in a broad range of pressures (1–25 bar) in order to determine the corresponding transfer parameters. Second, complete PSA simulations are conducted. More precisely, a multi-objective analysis is carried out having the CO₂ purity and recovery as objectives. A fixed process configuration is considered and the optimization is repeated for different process conditions. The results of this analysis are then compared to a benchmark which has activated carbon as adsorbent. This comparison shows that the USO-2-Ni MOF indeed increases both the separation performance and the productivity of the PSA process with respect to activated carbon. UiO-67/MCM-41 hybrid exhibits a slightly worse separation performance, but a better specific adsorbent productivity than activated carbon. Furthermore, it is shown that the particle formulation is crucial, as it has a big impact on the packing characteristics, which in turn have a big impact on the process performance.