Modeling the effect of wall capacitance on the dynamics of an exothermic reaction system in a batch reactor

The chemical reactors in certain range of operating conditions may exhibit parametric sensitivity where small changes in one or more of the input parameters lead to large changes in the output variable. This is a form of critical behavior that leads to runaway conditions, resulting in hazardous reactor operation. In the present work, hydrolysis of acetic anhydride reaction was used to investigate the existence and effect of parametric sensitivity with respect to the input parameters, namely cooling water flow rate, cooling water feed temperature and wall capacitance. Parametric sensitivity was observed for a small change in coolant water flow rate and feed temperature. It is found experimentally that with the introduction of extraneous wall capacitance, the batch reactor showed non-sensitivity under parametric sensitivity conditions. A mathematical model for the reactor was developed by incorporating both mass and energy balance with ordinary coupled differential equations. This dynamic model was solved numerically using ODE15s (gear method) of Matlab software, and the numerically simulated results are in satisfactory agreement with the experimental data.