Vacuum gas oil hydrocracking on NiMo/USY zeolite catalysts. Experimental study and kinetic modeling

A bench-scale experimental unit based on a Robinson-Mahoney reactor with completely mixed gas and liquid phases was used to study the hydrocracking of a light vacuum gas oil on two base metal sulfide containing acid catalysts, characterized by their textural properties, NH₃-TPD and pyridine-adsorbed Fourier-transformed infrared (Py-FTIR) acidity. The reactor effluent was analyzed in great detail by means of online gas chromatography and gas chromatography-mass spectrometry which evidenced the role of the catalyst acidity. The detailed analysis allowed the reaction scheme to be expressed at the level required by the kinetic analysis in terms of the fundamental Single Event Kinetics approach and thus drastically reduce the number of independent kinetic parameters to be determined from the experimental data. Reactor simulations illustrate the detailed predictions made possible by this approach.