Modeling and simulation of an integrated multi-shell fixed bed membrane reactor with well-mixed catalyst pattern for production of styrene and cyclohexane

A rigorous two-dimensional steady state mathematical model based on the dusty gas model is implemented to investigate the performance of a bench-scale integrated multi-shell fixed bed membrane reactor with well-mixed catalyst pattern for simultaneous production of styrene and cyclohexane. Since the styrene producing reaction is equilibrium limited, significant displacement of the thermodynamic equilibrium is achieved by three simultaneous actions of an auxiliary hydrogenation reaction of benzene using a well-mixed catalyst pattern, the membrane and the multi-shell reactor configuration. The simulation results show that the complete conversion of ethylbenzene is possible at relatively low temperature and shorter reactor length. Effective operating regions with optimal conditions are observed and explanations offered. An effective length criterion for the optimal conditions is presented. The effective operating regions are found to be sensitive to changes of catalyst bed composition, feed temperature, feed pressure and shells ratio. It is also found that the multi-shell configuration is superior to the single shell configuration. Although this investigation is restricted to two catalysts and two shells, some of the rich characteristics of this system have been uncovered.

► Production of styrene and cyclohexane in efficient multi-shell membrane reactors. ► Significant displacement of the thermodynamic equilibrium. ► High conversion and low temperature at shorter reactor bed. ► An effective reactor length criterion for the reactor performance. ► Optimal effective operating regions.