Hydrocarbon composition of liquid products of catalytic oxy-cracking of vacuum gasoil

Abstract

The hydrocarbon composition of liquid products of oxycracking of vacuum gas oil obtained in the presence of a zeolite-containing catalyst has been studied. It has been established that the group hydrocarbon composition of the liquid oxycracking catalyzate is significantly affected by the process parameters. When considering the influence of the process temperature, it was found that the concentration of C5-C9 and C10+ alkanes has an opposite temperature dependence: the C5-C9 yield passes through a maximum at a temperature of 500°C, while for C10+ it is a minimum temperature; there is a linear relationship between the temperature and the yield of unsaturated; the yield of naphthenes gradually decreases with increasing temperature; elevated temperatures contribute to an increase in the total yield of aromatic hydrocarbons. When varying the duration of the process, it was revealed: within 900 seconds from the beginning of the process, the most significant decrease in concentration was noted for aromatic hydrocarbons. The low oxidation state of 0.5% contributes to the intensive conversion of high molecular weight alkanes and aromatic hydrocarbons with long side chains; the concentration of oxygen-containing compounds raises with an increase in the degree of oxidation to 1%, passing through a maximum. The contact time with the catalyst had a complex effect on the hydrocarbon composition of the liquid products of vacuum gas oil oxycracking: a short contact time contributes to a decrease in the concentration of high molecular weight paraffinic and naphthenic hydrocarbons and an increase in aromatic hydrocarbons; with a subsequent increase to 2 s, it drops sharply. The obtained data made it possible to establish the fundamental distinguishing features of the catalytic oxycracking of vacuum gas oil from the traditional catalytic and noncatalytic oxidative ones, and also to propose a list of reactions occurring during the catalytic oxycracking of vacuum gas oil.