Fremgangsmåde til fremstilling af benzin med højt octantal ud fra en tung naphtha

1338612 Cracking and reforming naphtha UNIVERSAL OIL PRODUCTS CO 16 Dec 1970 [17 Dec 1969] 59689/70 Heading C5E An aromatic gasoline and saturated and unsaturated hydrocarbons having three or four carbon atoms in the molecule are made from a feedstock comprising both alkanes and naphthenes boiling in the range 82‹ to 204‹ C. by first reforming the feed under conditions to convert more than 80% of the naphthenes but less than 40% of the alkanes to aromatics, then separating the product into an aromatic gasoline stream and a saturated hydrocarbon stream by solvent extraction and finally cracking the saturated stream in a fluidized bed of catalyst without added hydrogen. The hydrocarbons of three or four carbon atoms may be used to make alkylate gasoline, or hydrolysed to alcohols or converted to amines, esters, ethers or ketones, all of which can be used as gasoline components. Suitable feedstocks are straight-run gasoline, natural gasolines, and thermally or catalytically cracked gasolines, and may be of full boiling range, or higher-boiling fractions only. Catalysts for the reforming step comprise carriers such as alumina, faujasite, mordenite or combinations of these and a reactive metal component such as Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt or Re and may also contain a combined halogen. The catalyst may be fluidized or otherwise moving, but is preferably in a fixed bed. Catalysts for the cracking step are silica-alumina, silica-magnesia, silica-zirconia and zeolites, natural or synthetic, and may be compounded by ion-exchange or impregnation with alkali metals, alkaline-earth metals, rare-earth metals or metals of Group VIII. As shown, feed in line 20 and hydrogen in line 21 pass to reforming at 15. The reformate is fractionated at 16 to give a hydrogen-rich gas stream 23, a stream 24 of hydrocarbons up to C 4 , a stream 25 of C 5 and C 6 hydrocarbons and a stream 26 of heavier hydrocarbons. Stream 26 is or streams 25 and 26 are extracted by a solvent at 17, and the aromatic extract taken off at 28. The raffinate in line 27 is cracked at 18 and fractionated at 19 to give cracked gasoline 31 and light hydrocarbons (C 3 and C 4 ) 30. The cracked gasoline can be recycled by line 33.