Ethylene and cyclohexane co-production in the fixed-bed catalytic membrane reactor: Experimental study and modeling optimization

Abstract

In this study, a fixed-bed catalytic membrane reactor was used for the production of ethylene and cyclohexane from ethane and benzene. A two-dimensional non-isothermal mathematical model was used for estimating the performance of the membrane reactor. Furthermore, the effect of inlet temperature (720–1080 K), feed molar ratio (3–10) and the reactor spacetime (1–76 kgCat.s/mol) was studied on the conversion of ethane to ethylene and benzene to cyclohexane. The results of modeling showed that with the increase of inlet temperature the conversion of both (de)-hydrogenation reactions increased and the 95% of ethane conversion was achieved when the molar ratio of benzene/ethane was fixed on 3. The hydrogenation of benzene at the shell side of the catalytic membrane reactor enhanced the production of ethylene due to the exothermic nature of the hydrogenation reaction, resulting in heat conduction through the membrane and glass substrate into the tube side. The comparison between experimental data reported in literature and modeling showed that the deviation of data obtained by mathematical modeling from experimental values ranged from 15.2 to 19.8% at various spacetimes. In addition, the results of sensitivity analysis showed that the conversion of benzene and ethane is more sensitive to the inlet temperature (up to 160% change on conversion) in comparison to the other parameters including feed ratio and the reactor spacetime. Moreover, at a temperature above 1128 K, the overall performance of the catalytic membrane reactor increased significantly.