Vacuum gas oil hydrocracking test in a semi-batch reactor: study of reaction mechanisms and vapor-liquid equilibrium
Résumé
A heavy gas oil hydrocracking catalytic test procedure has been developed in order to have a better characterization of catalyst performance. This method associates a semi-batch reactor test allowing on-the-run sampling, and quantitative analysis of the feed and the effluents by two-dimensional gas chromatography. Combining these experimental tools allowed the tracking of the operating conditions and the composition of each phase of the reactor during the experiments. This method has then been applied to test bifunctional catalysts with different NiMoS and zeolite contents. It has been shown that the zeolite content is the determining parameter for the global conversion rate, and that the sulfide/acid sites ratio affects the middle distillate selectivity. Also, liquid-vapor transfer limitations have been proven to be negligible and there are indications that transport of the hydrocarbons in the zeolite pores may be a limiting step.