US 5,290,427 A · Gasoline upgrading process

Abstract

Low sulfur gasoline is produced from a catalytically cracked, sulfur-containing naphtha by fractionating the naphtha feed into a number of fractions of differing boiling range and hydrodesulfurizing them by by feeding them into a hydrodesulfurization reactor at spaced locations along the length of the reactor in order of descending boiling range, with the highest boiling fraction first. Staged introduction of the feed into the hydrodesulfurization reactor in this way promotes desulfurization of the sulfur-rich, olefin poor back end of the feed while reducing the saturation of the high octane olefins in the olefin-rich, sulfur-poor front end, so preserving octane while achieving the desired desulfurization. The hydrodesulfurization is followed by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5. The treatment over the acidic catalyst in the second step restores 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.

Claims30

Dependent claims

A process of upgrading a sulfur-containing feed fraction boiling in the gasoline boiling range which comprises:

fractionating the feed into a plurality of fractions of differring boiling range,
hydrodesulfurizing the fractions by introducing them into a fixed bed hydrodesulfurization reactor at spaced locations along the length of the hydrodesulfurization reactor in which the introduced fractions are contacted with a hydrodesulfurization catalyst under conditions of elevated temperature, elevated pressure and in an atmosphere comprising hydrogen, to produce an intermediate product comprising a normally liquid fraction which has a reduced sulfur content 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 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.

A process of upgrading 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., which process comprises:

separating the sulfur-containing feed into a plurality of fractions of differing boiling range,
hydrodesulfurizing the feed fractions with a hydrodesulfurization catalyst by introducing the feed fractions into a fixed-bed hydrodesulfurization reactor at spaced locations along the length of the reactor in order of descending boiling range of the fractions and carrying out the hydrodesulfurization under conditions of elevated temperature, elevated pressure and in 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 an acidic zeolite catalyst 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.

Gasoline upgrading process

Life of this patent

Gasoline upgrading process

Life of this patent

Abstract

Claims30