FCC-benzinekben lévô egyedi olefinek átalakulásának vizsgálata a hidrogénezô kéntelenítés körülményei között

During heterogeneous catalytic desulphurization of FCC gasoline (full range or heavy FCC gasoline) many chemical reactions take place apart from the main reactions. Thus the hydrocarbon composition of the final product changes which significantly influences other important properties (e.g.: researchand motor octane number, storage stability etc.) of the product. In the paper conversion of individual olefins and its effect on the octane number was investigated in a laboratory scale reactor system.

Based on the results in case of the conversion of full range FCC gasoline on the novel Pt-Pd/USY catalyst it was established that mainly cracking, double bond isomerization, skeletal isomerization, saturation of olefins and hydrogenation of aromatics occur. The rate of these reactions – apart from the applied catalyst (T = 220-290°C, P 7 30 bar, H2/HC volume ratio: 300 Nm3/m3) – mainly depends on the process parameters.
It was established that the octane number is mainly affected by the high rate of olefin saturation. Under certain reaction parameters (270-300°C) saturation of aromatics can reach such a rate that it decreases the octane number. Conversion of terminal olefins to internal ones and skeletal conversion of n-paraffins are the octane number increasing reactions. As a consequence of the explored and investigated reactions chemical composition of FCC gasolines tends to be paraffinic. This can cause the decrease of the research octane number (ΔRON(product-feedstock) cca. -0.3 and -5 units) depending on the applied catalyst. Decrease of the motor
octane number is lower (between cca. -0.2 and -3.5) because of the better sensibility of paraffins.

Dr. Magyar Szabolcs, Dr. Hancsók Jenô