Method for upgrading C5 plus product of Fischer-Tropsch Synthesis

Claim 1

In a process combination wherein the effluent of Fischer-Tropsch synthesis is cooled, water washed and separated to provide a decant oil fraction, a liquid hydrocarbon fraction boiling below said decant oil fraction, a gaseous fraction and a water phase, the method for upgrading the hydrocarbon fractions thus recovered which comprises, combining the decant oil fraction with the lower boiling liquid hydrocarbon fraction and separating the combined fractions under conditions to recover a first gasoline and lower boiling fraction, a light oil fraction, and a heavy waxy oil fraction of an end point of about 850° F., said light oil fraction having an initial boiling point within the range of 325° to 400° F. and an end boiling point within the range of 600° to 650° F., subjecting the light oil fraction to catalytic hydrogenation under conditions to produce upon separation of the product, a diesel fuel product, a jet fuel product and a second gasoline containing fraction comprising lower boiling components, separating the gaseous fraction recovered from the Fischer-Tropsch synthesis product under conditions to recover an ethylene rich fraction, lower boiling gaseous material, a fraction comprising C 2 to C 4 hydrocarbons and a fraction comprising C 5 and higher boiling materials, separating said C 2 to C 4 hydrocarbon fraction into an ethylene rich stream and a C 3 to C 4 stream thereafter passed to catalytic polymerization, combining said C 5 and higher boiling fraction with said first gasoline and lower boiling fraction above recovered and contacting the thus combined materials wth a crystalline zeolite catalyst under conditions selective for producing a gasoline product of improved octane rating, combining the effluent of the crystalline zeolite catalyst step with the recovered second gasoline fraction and separating the thus combined material to recover a third gasoline product fraction of improved octane rating, a C 4 minus gaseous fraction and product fraction boiling above said third gasoline product fraction, separating the C 4 minus gaseous fraction above recovered with the product effluent of said catalytic polymerization operation to recover material higher boiling than gasoline, a C 2 minus material fraction and a C 3 -C 4 rich stream thereafter passed to catalytic alkylation and blending an alkylate product with said gasoline product of improved octane above recovered.