Gasoline upgrading process
AssigneeMobil Oil Corporation
InventorsStuart S-S. Shih, Kathleen M. Keville, Daria N. Lissy
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Abstract
Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurization followed by treatment over an acidic catalyst system comprising a zeolite having the topology of ZSM-5 and a zeolite sorbing 10 to 40 mg 3-methylpentane at 90.degree. C., 90 torr, per gram dry zeolite in the hydrogen form, e.g., ZSM-22, ZSM-23, or ZSM-35. The treatment over the acidic catalyst system in the second step restores the octane loss which takes place as a result of the hydrogenative treatment and results in a low sulfur gasoline product with an octane number comparable to that of the feed naphtha.
Claims17
A process of upgrading a sulfur-containing feed fraction boiling in the gasoline boiling range which comprises:
- contacting the sulfur-containing feed fraction with a hydrodesulfurization catalyst in a first reaction zone, operating under a combination of elevated temperature, elevated pressure and an atmosphere comprising hydrogen, to produce an intermediate product comprising a normally liquid fraction which has a reduced sulfur content and a reduced octane number as compared to the feed;
- contacting at least the gasoline boiling range portion of the intermediate product in a second reaction zone with a catalyst system of acidic functionality comprising a zeolite having the topology of ZSM-5 and a constrained intermediate pore zeolite sorbing 10 to 40 mg 3-methylpentane at 90.degree. C., 90 torr 3-methylpentane, per gram dry zeolite in the hydrogen form, to convert said portion to a product comprising a fraction boiling in the gasoline boiling range having a higher octane number than the gasoline boiling range fraction of the intermediate product.
A process of upgrading a sulfur-containing feed fraction boiling in the gasoline boiling range which comprises:
- hydrodesulfurizing a catalytically cracked, olefinic, sulfur-containing gasoline feed having a sulfur content of at least 50 ppmw, an olefin content of at least 5 percent and a 95 percent point of at least 325.degree. F. with a hydrodesulfurization catalyst in a hydrodesulfurization zone, operating under a combination of elevated temperature, elevated pressure and an atmosphere comprising hydrogen, to produce an intermediate product comprising a normally liquid fraction which has a reduced sulfur content and a reduced octane number as compared to the feed;
- contacting at least the gasoline boiling range portion of the intermediate product in a second reaction zone with a catalyst system of acidic functionality comprising a zeolite having the topology of ZSM-5 and a zeolite sorbing 10 to 40 mg 3-methylpentane at 90.degree. C., 90 torr, per gram dry zeolite in the hydrogen form, to convert it to a product comprising a fraction boiling in the gasoline boiling range having a higher octane number than the gasoline boiling range fraction of the intermediate product.
Dependencies are inferred from the claim text.