CATALYST FOR LOWERING CONTENT OF BENZENE AND UNSATURATED HYDROCARBONS IN GASOLINE FRACTIONS, METHOD FOR PREPARATION THEREOF, AND A METHOD FOR LOWERING CONTENT OF BENZENE AND UNSATURATED HYDROCARBONS IN GASOLINE FRACTIONS

摘要

FIELD: petroleum processing and petrochemistry.;SUBSTANCE: invention relates to catalysts for isomerization of paraffins and alkylation of unsaturated and aromatic hydrocarbons contained in hydrocarbon stock. Catalyst of invention is characterized by that it lowers content of benzene and unsaturated hydrocarbons in gasoline fractions in above isomerization and alkylation process executed in presence of methanol and catalyst based on high-silica ZSM-5-type zeolite containing: 60.0-80.0% of iron-alumino-silicate with ZSM-5-type structure and silica ratio SiO₂/Al₂O₃ = 20-160 and ratio SiO₂/Fe₂O₃ = 30-550; 0.1-10.0% of modifying component selected from at least one of following metal oxides: copper, zinc, nickel, gallium, lanthanum, cerium, and rhenium; 0.5-5.0% of reinforcing additive: boron oxide, phosphorus oxide, or mixture thereof; the rest being alumina. Preparation of catalyst includes following steps: hydrothermal crystallization of reaction mixture at 120-180C during 1 to 6 days, said reaction mixture being composed of precursors of silica, alumina, iron oxide, alkali metal oxide, hexamethylenediamine, and water; conversion of thus obtained iron-alumino-silicate into H-iron-alumino-silicate; further impregnation of iron-alumino-silicate with modifying metal compound followed by drying operation for 2 to 12 h at 110C; mixing of dried material with reinforcing additive, with binder; mechanochemical treatment on vibrating mill for 4 to 72 h; molding catalyst paste; drying it for 0.1 to 24 h at 100-110C; and calcination at 550-600C for 0.1 to 24 h. Lowering of content of benzene and unsaturated hydrocarbons in gasoline fractions in presence of above catalyst is achieved during isomerization and alkylation of hydrocarbon feedstock carried out at 300-500C, volumetric feedstock supply rate 2-4 h-1, weight ratio of hydrocarbon feedstock to methanol 1:(0.1-0.3), and pressure 0.1 to 1.5 MPa. In particular, hydrocarbon feedstock utilized is fraction 35-230C of hydrostabilized liquid products of pyrolysis.;EFFECT: facilitated reduction of benzene and unsaturated hydrocarbons in gasoline fractions and other hydrocarbon fuel mixtures.;3 cl, 1 tbl, 13 ex