New Approach for Absorbent Species Selection with Excess Gibbs Function

Abstract

Absorption capacities were analyzed based on 33 sets of vapor–liquid equilibrium literature data that focused on eight solute-based binary systems, namely, carbon dioxide, dimethyl ether, ethylene, difluoromethane, water, methane, 1,1,1,2-tetrafluoroethane, and sulfur dioxide. The absorbents were classified into solvent type and ionic liquid type. The regularities of the excess Gibbs function (GE) of the binary systems were investigated by evaluating the macroscopic properties and the influence of intermolecular interactions between the solute and the absorbent based on the concept of local composition model. The extreme value (GEmax) and the absorption potential (ψi) were proposed as absorbent selection criteria. An evaluation method predicting the activity coefficient and evaluating the systems with GEmax and ψi through the UNIFAC model was established. Consequently, the validity study of the new approach for the eight solute-based binary systems was in agreement with previously assessed experimental behavior trends.