Study of the activity of bifunctional catalyzers on the transformation of n-hexane

Abstract

The production of various motor fuels is carried out by processing light fractions of oil with an initial temperature of boiling to 350°С. The current trend shows that oil in new fields has more weight than before. New oil reservoirs are deeper with a greater proportion of dark fraction with a boiling point of 350°С. This situation stimulates to find new ways of increasing the processing depth light fractions for synthesis target product. One of the main solution path for the problem is creation of new catalytic systems or modernization of existing ones. Motor fuels must meet the necessary operational and environmental characteristics, which is determined by their chemical composition. This article is devoted to the study of bifunctional catalyzers for the conversion of n-hexane. High molecular zeolite CVM (ZSM-5) was used as a carrier, which has functionality due to the presence of various active centers. Platinum (Pt/CVM), praseodymium (Pr/CVM) were also applied to the carrier, and praseodymium and platinum (Pt,Pr/CVM) were successively applied by impregnation. Normal hexane was used as a raw material. The choice of this raw material is associated with the ability to aromatization reaction, as well as the presence of n-hexane in the raw materials of the process of obtaining motor fuels-catalytic reforming. As a result of the transformation of raw materials, liquid fuel of multicomponent composition with the number of carbon atoms in the chain from 3 to 14, as well as gases containing C1 – C5 hydrocarbons, was obtained. When n-hexane is converted on the catalyzers under study, both the octane number and the content of aromatic hydrocarbons increase with increasing temperature. It has been found that when the process is carried out at a temperature of 450°C, the highest yield of the catalysate is (33.8% by weight.) on a Pt,Pr/CVM catalyzer. With an increase in temperature, the yield of benzene increases. Minimum benzene yield (0.6 wt. %) is achieved at 450°C marked by a bimetallic catalyzer, which corresponds to the EURO-5 gasoline standard. The highest degree of conversion was observed during the conversion of n-hexane on the Pt,Pr/CMC catalytic system at a temperature of 450° C, which was (97%).