Mathematical description of hydrofining of catalytically cracked light gasoline fraction

Abstract

A regression model of the process of hydrofining of catalyticallycracked light gasoline fraction, which describes the experimental data accurately, has been developed. The quantitative ratios showing the influence of the basic technological parameters on the process indices (data) have been established. The optimal values of the input variables, which allow for production of gasoline with maximum octane number and minimum sulfur content, have been determined.The increase in the automobile fleet has led to rapid pollution of the air basin by effluent gases from internal-combustion engines, which contain more than 300 compounds that are harmful to the environment and the human organism [1,2].Modern fuels should meet a number of ecological requirements corresponding to European standards Euro-3 and Euro-4. One of the ecologically dangerous components of motor fuel is sulfur, the content of which should not exceed 10-30 ppm.Hydrofining is the process most widely used in industry to produce high-quality low-sulfur motor fuel. In this process, sulfur-containing compounds are subjected to destructive hydrogenation with the formation of hydrogen sulfide and hydrocarbons. Here, however, hydrogenation reactions of olefin and aromatic hydrocarbons also occur, resulting in a reduction in the octane number of the gasoline cuts. To elevate the octane number, we investigated the possibility of creating effective hydrofining catalysts that permit simultaneous hydroisomerization.Catalytically cracked gasoline (CCG) produced during refinement of a feedstock formed from a mixture of Azerbaizhan crudes was selected as the feedstock. The content of total and mercaptan sulfur was 180 and 23 ppm, respectively, and that of the olefins 8-9 wt. %. The content of mercaptan sulfur exceeded the allowable value by a factor of two. To ascertain the optimal desulfurization scheme, the CCG was separated into the following narrow fractions: IBP -130°C and 130°C -EP, the yield of which was, respectively, 60 and 40% gasoline. It is established