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A simplified proxy model based on a well-mixed batch adsorber for vacuum swing adsorption (VSA) based CO 2 capture from dry postcombustion flue gas is presented. A graphical representation of the model output allows for the rationalization of broad trends of process performance. The results of the simplified model are compared with a detailed VSA model that takes into account mass and heat transfer, column pressure drop, and column switching, in order to understand its potential and limitations. A new classification metric to identify whether an adsorbent can produce CO 2 purity and recovery values that meet current U.S. Department of Energy (US-DOE) targets for postcombustion CO 2 capture and to calculate the corresponding parasitic energy is developed. The model, which can be evaluated within a few seconds, showed a classification Matthew correlation coefficient of 0.76 compared to 0.39, the best offered by any traditional metric. The model was also able to predict the energy consumption within 15% accuracy of the detailed model for 83% of the adsorbents studied. The developed metric and the correlation are then used to screen the NIST/ARPA-E database to identify promising adsorbents for CO 2 capture applications.

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Steady-state single-component and ternary mixture xylene permeation fluxes through Ba−ZSM-5/SS composite membranes were studied, as a function of temperature and pressure. The single p-xylene flux has a weak maximum, relative to temperature (100−400 °C). The flux magnitude and its maximum location are dependent on the extent of Ba-exchange. The o- and m-xylene fluxes steadily increase with temperature. The single permeation behavior is well-described by a model based on the contribution of different transport mechanisms:  Knudsen flux, surface diffusion, and activated gas translation diffusion. The comparisons between either the mixture permeation results or the pressure effect experiments and the simulated data reflect the existing adsorbate-framework interactions that are not easily contemplated by a macroscopic model.