Composition and quality of the gasoline obtained from syngas on Cr2O3-ZnO/ZSM5 catalysts

The kinetic equations for the formation of the lumps of the gasoline produc ed (C-5(+) fraction), paraffins (C-5-C-8), xylenes (o-xylene, m-xylene and p-xylene) and aromatics (benzene, toluene, C-9-C-11) in the transformation of syngas on Cr2O3-ZnO/ZSM5 bifunctional catalyst have been established as a function of the concentration of both reactants (CO and H-2) and CO2 bypr oduct. The effect of the operating conditions on the RON and on the molecul ar weight of the gasoline has been studied by experimentation in an integra l fixed bed reactor in the range between 10 and 50 atm and between 300 and 425 degrees C. The octane index increases with Cr/Zn atomic ratio of the Cr 2O3-ZnO metallic function, with Si/Al ratio of the HZSM5 zeolite, with spac e time and with the CO/H-2 molar ratio in the feed, in that order, whereas it passes through a maximum with pressure (at 20 atm) and with temperature (at 375 degrees C). On the other hand, the molecular weight of the gasoline increases with the Cr/Zn atomic ratio, pressure, CO/H2 molar ratio and spa ce time, and decreases with the Si/Al ratio and temperature.