Heat integration of isobutane dehydrogenation and hydrogenation of nitrobenzene to aniline in radial flow moving bed reactors: Modelling and operability investigation

In the process intensification subject, heat integration of endothermic and exothermic reactions in a shell and tube reactor is one of the most important approaches to reduce plant size and decreasing operational cost compared to conventional processes. This paper focuses on modelling and simulation of thermally coupled radial flow moving bed reactors to produce isobutene and aniline. A steady state heterogeneous two-dimensional model is developed to predict the performance and operability of the proposed configuration against conventional process. The catalytic nitrobenzene hydrogenation takes place in the exothermic side and supplies a part of necessary heat for isobutane dehydrogenation in the endothermic side. To prove the accuracy of the considered mathematical model and assumptions, the simulation results of the conventional process are compared with the plant data at the same process condition. Isobutane conversion is enhanced about 5.3% in the thermally coupled process compared to the conventional process. In addition, since the nitrobenzene hydrogenation reaction supplies a part of required heat in the isobutane dehydrogenation side, the smaller furnaces can be used in the commercial Oleflex process.