In chemical processing, simultaneous reaction and separation of the product help to increase conversion rate and productivity, and saves material handling and processing costs. In this study, a sensitivity analysis of heterogeneous Reactive Distillation (RD) using Aspen Plus was carried out to understand the complex behavior of a reactive distillation column. The esterification reaction of methanol by acetic acid to form methyl acetate was considered for the sensitivity analysis. The steady state results were validated with the experimental results reported by Popken et al. (2001). Considering these steady state results as reference, sensitivity analysis was done. In the simulation, RADFRAC model was chosen to take care of the complexities arising due to simultaneous reaction and separation in a single unit. UNIQUAC property method was selected in the simulator for equilibrium calculations.

Reactive Distillation (RD) is a combination of reaction and distillation in a single unit having a number of specific advantages over conventional sequential approach of reaction followed by distillation or any other separation techniques. The combined effect of reaction and separation increases the selectivity of the product and enhances the conversion of the reactant. The RD unit provides better control and proper utilization of reaction heat. Moreover, easier separation of the components can be achieved and formation of azeotropes can be avoided in the RD column. The complex behavior of the RD column arises because of the complicated vapor-liquid interactions, mass transfer between solid, liquid and vapor phases, intra-particle (catalyst) diffusion in the case of catalyzed reactions, and reaction kinetics involved with separation. Therefore, such kinds of multi directional interactions in the RD system lead to multiple steady-states and complex dynamics (Taylor and Krishna, 2000).

Therefore, to understand the complete behavior of the simultaneous reaction and separation process, research on various fields, like modeling and simulation, process synthesis, column design, nonlinear Vapor-Liquid Equilibrium (VLE) behavior, and development of control strategy, has been on. But the feasibility of the RD process for a particular reaction may depend upon some of the important factors like relative volatilities of the components involved in the reaction, column and reaction temperature, pressure, optimum reflux ratio, etc. Hence, RD may not always be the choice for every chemical reaction. Hence, substantial consideration to enlarge the domain of research on RD processes is required.

Science and Technology Journal, Sensitivity Analysis, Heterogeneous Reactive Distillation, Multi Directional Interactions, Aspen Plus Process Simulator, Thermodynamic Studies, Aspen Plus Simulation Software, Molar Reflux Ratio, Acetic Acid, Methyl Acetate, UNIQUAC Property Method, Methanol Esterification.