Chemical Engineering Science, Vol.205, 165-173, 2019
Swapping the equilibrium
A "swapped equilibrium" (SE) occurs when the initial concentrations of two chemical species are taken as their equilibrium concentrations, but swapped. In complex mechanisms, this implies that the initial concentrations of the other chemical species remain equal to their corresponding equilibrium concentrations; a phenomenon called Conservatively Perturbed Equilibrium (CPE), described in a previous paper (Chem. Eng. Sci. 196, 2019, 384-390). The SE-phenomenon is illustrated for both a single-step and a two-step mechanism with first-order reactions. For the two-step mechanism, invariant expressions are obtained based on the corrected ratios of CPE concentration profiles, while the other two chemical species are under swapped equilibrium conditions. For the related CPE case, invariant expressions are also obtained considering the same two-step mechanism. The CPE-properties described previously (Chem. Eng. Sci. 196, 2019, 384-390) are now completed with the invariant expressions presented now, specific for the two-step linear mechanism. (C) 2019 Published by Elsevier Ltd.