(584l) Reaction Kinetics of 1-Methylnapthalene Hydrocracking over Metal/Beta Catalyst to BTX

Light cycle oil (LCO, in diesel boiling point range), mainly composed of two-aromatic ring compounds, is produced in large amounts through FCC process in oil refineries. Since the demand for heavy fuel oil and diesel is in steady reduction recently, it is highly desirable to convert this fraction into high-value products, i.e., light alkyl aromatic hydrocarbons such as BTX (benzene, toluene and xylene), for which demands are steadily increasing.

To produce BTX, one aromatic ring of LCO must be selectively preserved to form one phenyl ring with alkyl chains. Selective hydrocracking (HC) is common ring opening reactions used for effective conversion of multiple-aromatic ring components to one-aromatic ring components, and bifunctional catalysts such as metals supported on acid zeolites have mostly been used for this purpose. However, there is hardly report on the inherent correlation between catalyst characteristics and reaction selectivity because of the high complexity of the LCO hydrocracking. The metallic catalytic centers and acid catalytic sites have hydrogenation function and cracking function respectively, and they cooperate during the selective hydrocracking of LCO. A reaction kinetic model is useful for the quantitative evaluation of the function of the metallic catalytic sites and the acid catalytic sites in the selective hydrocracking process, and therefore can be used to guide the preparation of good selective LCO hydrocracking catalysts.

In this work, we studied the hydrocracking kinetics of 1-methylnaphthalene as a model molecule of the LCO. The hydrocracking experiments were conducted using metals/Beta molecular sieve as the catalyst (Metals = NiW, NiMo, CoMo, CoW, W, Mo) and a six-lump reaction kinetic model was proposed. A mathematic kinetic model was established, and all kinetic constants and the activation energy of every step reaction in the reaction model were obtained. There is a good consistency between the kinetic model and experimental data, indicating that the kinetic model are reliable.