METHOD OF PRODUCING LOW-OCTANE AND HIGH-OCTANE GASOLINES AND BENZENE FROM CATALYSATES OF REFORMING OF LONG GASOLINE DISTILLATES Russian patent published in 1998 - IPC

FIELD: petrochemistry and gasoline production. SUBSTANCE: gasolines and benzene are produced by separating reforming product in tray rectification column into three fractions: head fraction containing C₂-C₆,- hydrocarbons, low-octane benzene-containing fraction, and high-octane still fraction. Head fraction is taken off in amount providing content of pentanes and hexanes in the fraction within the range 30 to 70% on the total amount of these hydrocarbons in reforming product. Amount of still fraction is chosen such that concentration of aromatic hydrocarbons in the fraction were 70-95 wt %. Low-octane benzene- containing fraction is separated by selective-solvent extraction into benzene-rich extract phase and raffinate phase. The latter may be combined either with reforming product fractions 62-105 or 70-180 C, or with narrower fractions of these to produce gasolines with octane number 76-81 points (motor method test). It can also be directly isomerized or combined with straight-run gasoline fraction 62-105 C for subsequent rectification to form top fraction 62-70 C which is further subjected to isomerization process and bottom fraction 10-105 C directed into the reforming process. Isomerization product is mixed with high-octane still fraction or with its mixture with head fraction to yield commercial gasolines with octane number 92-96 points (research method) when supplemented by 1-5 wt % of isopentane, 1-15 wt % of pentane-hexane fraction (octane number 75-80 points by research method), 4-15 wt % of methyl-tert-butyl ether or its mixture with trimethylcarbinol (40 wt %). EFFECT: increased (by 15-20 wt %) high-octane gasoline production, improved environmental characteristics of gasolines, and reduced (up to 5-7%) use of benzene. 2 cl