STEADY-STATE AND DYNAMIC BEHAVIOR OF GAS-LIQUID REACTORS

Steady state and dynamic behavior are studied for a gas-liquid CSTR, and steady state behavior is explored for a bubble column. Reaction factors are used to account for the effect of chemical reaction on the rate of gas absorption.;In a non-adiabatic gas-liquid CSTR, a steady state model is developed for second-order reactions; uniqueness and multiplicity regions are determined, in terms of the ignition and extinction points, in the parameter space of reactivity versus liquid residence time; and, various multiplicity patterns are analyzed. The pseudo-first-order reaction model is justified for the prediction of multiplicity regions of the second-order reaction. A dynamic model is set up for fast pseudo-first-order reactions; analytic necessary and sufficient criteria are derived for the prediction of steady state uniqueness and multiplicity, asymptotic stability of the steady states, and the direction and asymptotic stability of the limit cycles as a function of system physico-chemical parameters.;For fast pseudo-nth-order reactions in a non-adiabatic bubble column, a steady state model is developed; analytic necessary and sufficient criteria are obtained for the prediction of uniqueness and multiplicity of the steady states. For the special case of fast pseudo-first-order reactions, the occurrence of multiple steady states is shown to be more possible in the bubble column than in the gas-liquid CSTR for equivalent system parameters.;For consecutive second-order reactions, the orthogonal collocation method is used to obtain the reaction factors and the reaction yields of the film and penetration theories. The differences between these two theories and the numerical and approximate solutions are found to be generally small, and thus the approximate film theory reaction factor can be applied in the development of steady state and dynamic models of gas-liquid reactors.