PROCESS FOR PREPARING HIGH-OCTANE FASOLINES Russian patent published in 1994 - IPC

FIELD: petrochemical industry. SUBSTANCE: high-octane gasolines are prepared by fractionation of the hydrocarbon fraction stock containing C₂-C₅ hydrocarbons having a final boiling temperature of gasoline fractions to isolate C₂-C₅ fractions and/or a stable C₅₊ fraction or light and heavy gasoline fractions. The C₂-C₅ fraction or its mixture with gaseous contact products are subjected to pyrolysis. The resulting products are mixed with the stable C₅₊ fraction or with the heavy gasoline fraction. The mixture is contacted with a catalyst based on zeolites having the structure ZSM S-11 including those modified by the elements of 1, II, III, Y, YI and YIII groups of the periodic system. High-octane gasoline and a residual fraction are isolated by rectification from the resulting high-octane gasoline fraction, and if a light gasoline fraction is isolated from the stock, said fraction is compounded with a high-octane fraction or with high-octane gasoline. The pyrolysis products are fractionated to isolate a pyrolysis gas and a pyrocondensate. The pyrolysis gas is mixed with either the stable C₅₊ fraction or with the catalyst, whereas the pyrocondensate is compounded with the high-octane gasoline fraction has been rectified. The light gasoline fraction has a final boiling temperature of 60-80 C, whereas the heavy gasoline fraction has a starting boiling temperature of 60-80 C. The stock is made to contact with the catalyst at temperature between 320 and 460 C and a pressure of 0.2-4 MPa. EFFECT: improved properties of the high-octane gasolines. 4 cl, 1 tbl