Reactive distillation (RD) processes may exhibit multiple steady states (MSS) under certain conditions. For proper design and operation of RD columns, all such states must be identified and analyzed. In this article, a packed RD column producing ethyl tertbutyl ether (ETBE) from tert-butyl alcohol (TBA) and ethanol (EtOH) is simulated for detection of MSS in Aspen Plus(R). A rate-based approach has been used to make the developed model more realistic than the alternative equilibrium-based approach. A base case model was developed and fine tuned to fit the actual experimental data. Sensitivity analysis was then performed with reboiler duty as the continuation parameter to trace the respective bifurcation curve. The results show the presence of output multiplicity at three distinct steady states. Temperature and composition profiles of the solution branches within the region of multiplicity were analyzed to identify the most stable and desirable steady state. These results can be utilized to figure out the optimum operating conditions to avoid excessive energy consumption.
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