Boosting the gasoline octane number in thermally coupled naphtha reforming heat exchanger reactor using de optimization technique

Abstract

Since the refineries are benefitted mostly from the catalytic naphtha reforming units, these units are of highly interest. This importance would generate continuous evolution of the technology in both the processing and equipment pieces of the technology. One of the promising developments in the naphtha reformers would be thermal coupling of the reactors in a heat exchanger configuration. In this study, the DE optimization technique has been used as a powerful tool to find the best operating parameters in the naphtha coupled reactors. Twenty-six decision variables have been considered in this optimization problem. The endothermic dehydrogenation of the catalytic naphtha reforming is coupled with an exothermic hydrogenation reaction (hydrogenation of nitrobenzene to aniline) through a shell and tube heat exchanger reactor. Catalyst mass distribution, exothermic inlet temperature, operating pressures, number of tubes in the exothermic side and the total molar flow rates are the most important optimized parameters. Maximizing the aromatics (octane number) in reformate is the best possible objective function in this research. The results show a significant increase in hydrogen and aromatics production rate of the optimized reactor compared with the non-optimized one. Hydrogen and aromatics have increased 72 and 41kmol/h, respectively. Besides, the exothermic tubes are considered for the third reactor in this work to maximize the aromatic and hydrogen production rates. These results are valuable for the procedure of designing a reactor in which both reactions are integrated.