GB585352A - Production of motor fuel and aromatic hydrocarbons from fischer synthesised hydrocarbon oils - Google Patents

Abstract

Hydrocarbons synthesized from CO and H2 are fractionated into two fractions of naphtha and gas oil boiling range respectively, the former is catalytically hydroformed, and the latter catalytically cracked, the hydroformed product is fractionated into a light, a heavy, and an intermediate aromatic-rich fraction, the cracked product is fractionated to separate a fraction of gasoline boiling range which is further separated into a light, a heavy and an intermediate aromatic-rich fraction, aromatic hydrocarbons are solvent extracted from one or both the intermediate fractions, and the light and heavy fractions are blended to form a gasoline. A Fischer synthetic hydrocarbon is separated into 123-424 and 440-650 DEG F. fractions. The former is reacted at 800-1000 DEG F. and 100-400 p.s.i. in the presence of hydrogen, and chromia or molybdena or other Group 6 oxide or mixture of sulphides. The product is fractionated to give a 210-250 DEG F. cut containing toluene and paraffins, an overhead of boiling range 130-210 DEG F., and a bottom cut, the two latter being mixed for gasoline blending. The intermediate cut is extracted below 0 DEG C. with SO2 and a paraffinic solvent such as pentane to give an extract phase, which is stripped of solvent, and worked up to recover pure toluene, and a raffinate phase, which is treated to recover solvent and paraffins which are blended with gasoline or fed to the hydroforming or cracking stages. The original 440-650 DEG F. is cracked at, say, 825-925 DEG F. with acid treated clay or silicaalumina or silica-magnesia, the products being separated into gases which may be alkylated, unconverted oil, and a 100-400 DEG F. fraction which is further fractionated to yield a 210-250 DEG F. cut, which is worked up to toluene or returned for cracking or hydroforming, and light and heavy fractions used for gasoline blending. Xylenes produced in the reforming may be converted with benzene and aluminium chloride to toluene. Fluidized catalysts may be used in the reforming and cracking zones.