An efficient method for combining the Adsorption Potential and Ideal Adsorbed Solution theories in simulation models of multicomponent adsorption columns is presented. The main advantage of this dual-theory approach is that it reduces the number of equilibrium measurements required to predict the breakthrough profiles. The validity of the dual-theory equilibrium procedure is illustrated by embedding it in a dynamic-column breakthrough model of adsorption of ternary mixtures of methane, ethane, and propane on activated carbon. The resulting dynamic model was found to be computationally efficient, and good agreement was obtained between the predicted and experimental breakthrough curves. It is shown that the two theories can be coupled in such a way as to provide a simple and practically useful method of correlating multicomponent adsorption equilibrium in dynamic process modeling studies.