Adsorption in a centrifugal field: A thermodynamic analysis

Abstract

External fields such as gravitational, centrifugal or electrical fields lead to an uneven spatial distribution of the chemical compounds of a system. In this work, we conceive a scenario where a packing bed is submitted to a centrifugal field, so that centrifugation and adsorption occur simultaneously. Our rotating packed bed is made up by two main regions: one, representing the bulk phase, the other, representing the total pore volume available for adsorption. At constant temperature, total volume, and total amount, the distribution of species of selected binary and ternary mixtures of hydrocarbons, carbon dioxide, and hydrogen sulfide is predicted by minimizing the total Helmholtz energy of the system. Confinement-modified equations of state are employed as thermodynamic model for the adsorbed phase, while the Peng-Robinson equation of state is used in bulk phase calculations. Our purely thermodynamic analysis reveal that coupling both phenomena could be useful to enhance adsorption, or increase the separation obtained when only centrifugation is considered.