Gasoline upgrading process
AssigneeMobil Oil Corporation
InventorHye K. C. Timken
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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, preferably an intermediate pore size zeolite such as ZSM-5 with controlled diffusion characteristics. The treatment over the acidic catalyst 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. In favorable cases, using feeds of extended end point such as heavy naphthas with 95 percent points above about 380.degree. F. (about 193.degree. C.), improvements in both product octane and yield relative to the feed may be obtained.
Claims30
A process of upgrading a catalytically cracked, olefinic 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 of acidic functionality having a maximum diffusion distance of less than 0.025 inch, to convert the gasoline boiling range portion of the intermediate feed 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 catalytically cracked, olefinic, sulfur-containing naphtha 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 the gasoline boiling range portion of the intermediate product in a second reaction zone with a solid particulate catalyst of acidic functionality and having a maximum diffusion distance from about 0.005 to about 0.025 inch to convert the gasoline boiling range portion of the intermediate product 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.