Novel Recuperative Configuration for Coupling of Methanol Dehydration to Dimethyl Ether with Cyclohexane Dehydrogenation to Benzene

Abstract

Coupling energy intensive endothermic reaction systems with suitable exothermic reactions improves the thermal efficiency of processes and reduces the size of reactors. One type of reactor suitable for such a type of coupling is the recuperative reactor. In this work, the catalytic methanol dehydration to dimethyl ether (DME) is coupled with the catalytic dehydrogenation of cyclohexane to benzene in a simulated integrated reactor formed of two fixed beds separated by a wall, where heat is transferred across the surface of tube. A steady state heterogeneous model of the two fixed beds predicts the performance of this novel configuration. The cocurrent mode is investigated, and the simulation results are compared with corresponding predictions for an industrial adiabatic methanol dehydration fixed-bed reactor operated at the same feed conditions. In this coupled reactor, benzene and hydrogen are also produced as additional valuable products in a favorable manner and autothermality is achieved within the reactor. This novel configuration can decrease the temperature of methanol dehydration reaction in the second half of the reactor and shift the thermodynamic equilibrium. Therefore, the methanol conversion and DME mole fraction increase by 1.82% and 1.6%, respectively. The influence of inlet temperature and the molar flow rate of exothermic and endothermic stream on reactor behavior is investigated. The results suggest that coupling of these reactions could be feasible and beneficial. An experimental proof-of-concept is needed to establish the validity and safe operation of the novel reactor.