Catalytic upgrading of heavy naphtha to gasoline: Simultaneous operation of reforming and desulfurization in the absence of hydrogen

Abstract

Reforming of heavy naphtha in the absence of hydrogen and under more moderate conditions compared with conventional naphtha reforming processes is a very attractive subject. Naphtha reforming in the absence of hydrogen along with desulfurization capability of zeolite catalysts has made the process considerably popular. In order to investigate the effect of operation conditions on the naphtha reforming process using zeolite catalyst in the absence of hydrogen, ZSM-5 catalyst (Si/Al = 50) was successfully synthesized. Three operation parameters including WHSV, temperature and pressure were selected as the main factors to determine the optimal conditions for obtaining maximum octane number, liquid recovery, sulfur conversion and minimum coke deposition on catalyst and benzene content as the responses for the modified Taguchi design of experiments. A model was proposed for each of the responses and the corresponding coefficients were obtained based on the experimental data. The analysis of the results of the experimental design was carried out based on the kinetic models proposed for naphtha reforming process in the absence of hydrogen. The optimum conditions to achieve maximum octane number, liquid recovery, and S conversion and minimum coke deposition on catalyst and benzene content were WHSV =4.02 h−1, temperature = 349.09°C, and pressure = 20 bar. The actual responses obtained using reactor tests under optimal conditions indicated that the proposed model was completely valid.