The effect of over-equilibrium, i. e., the effect at which the concentration of some substance is higher than the corresponding equilibrium value, is demonstrated for two types of ideal chemical reactors, continuously stirred tank reactor (CSTR) and plug-flow reactor (PFR), respectively, under conditions of conservatively perturbed-equilibrium (CPE). Two types of complex chemical mechanisms are analyzed, acyclic and cyclic ones. Using numerical experiments and the same residence times, it is shown that for the steady-state PFR this effect is more pronounced that for the steady-state CSTR, and it is true both for acyclic and cyclic reactions. In the studied mechanisms, cyclic and acyclic, the initial concentration of some substance is taken as the equilibrium one, and two other concentrations are the nonequilibrium ones. The greater the difference between the two initially nonequilibrium concentrations, the greater the concentration of the third substance, which was taken initially as the equilibrium one. At the specific values of kinetic parameters considered here, the sensitivity of the occurrence time of the B-concentration extremum for the different reactors (PFR and CSTR) at the fixed mechanism is small, but for the different mechanisms (acyclic and cyclic) at the fixed reactor is significant.

The phenomenon of conservatively perturbed-equilibrium (CPE) in multi-route catalytic reactions was studied in the plug-flow reactor (PFR). The following multi-route mechanisms were chosen for studying, i.e., the two-route mechanism with the single common intermediate, the three-route mechanism with some common steps, and the two-route mechanism with the single common step and two common intermediates. All mentioned mechanisms exhibit the CPE-phenomenon. At given rate coefficients, the mechanism with the single common intermediate showed the greater CPE-effect than the mechanism with the common steps. A special computer experiment was performed in which the kinetic characteristics of non-catalytic and catalytic reactions have been compared. In this experiment, both non-catalytic and catalytic reactions have the same overall-reactions with the given equilibrium constant. It was shown that the absolute values of extreme concentrations at the CPE-point are almost the same. In this case, it is possible to estimate the concentrations at the CPE-values for complex reactions based on similar characteristics of the corresponding simple ones.