US 5,326,463 A · Gasoline upgrading process

Abstract

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurization and treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5 in an octane restoration step, followed by separation of a C.sub.9 -containing fraction, and recycling the C.sub.9 -containing fraction to the octane restoration step. A hydrocarbon fraction comprising C.sub.1 to C.sub.3 hydrocarbons may also be separated from the octane restored product and recycled for purposes of alkylating aromatic hydrocarbons and for this purpose, it may be advantageous to introduce a benzene-rich feed, such as a reformate, to the process. The treatment over the acidic catalyst in the octane restoration 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.

Claims18

Dependent claims

A process of upgrading a sulfur-containing catalytically cracked feed fraction having a 95% point of at least about 325% and boiling in the gasoline boiling range which comprises:

contacting the sulfur-containing catalytically cracked feed fraction with a hydrodesulfurization catalyst in a hydrodesulfurization 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 high in paraffins 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 produce in an octane restoration reaction zone with a catalyst of acidic functionality to convert it to a produce comprising a fraction high in olefins boiling in the gasoline boiling range having a higher octane number than the gasoline boiling range fraction of the intermediate product;
separating a fraction which contains a substantial amount of C.sub.9 hydrocarbons from the product of the octane restoration reaction zone by fractionation;
and
recycling at least a portion of the C.sub.9 containing fraction to at least one of the reaction zones.

2 more elements

A process of upgrading a sulfur-containing catalytically cracked feed fraction having a 95% point of at least about 325.degree. F. and boiling in the gasoline boiling range which comprises:

contacting the sulfur-containing catalytically cracked feed fraction with a hydrodesulfurization catalyst in a hydrodesulfurization 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 the intermediate produce in an octane restoration 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;
separating a fraction which contains a substantial amount of C.sub.9 hydrocarbons from the product of the octane restoration reaction zone by fractionation;
recycling at least a portion of the C.sub.9 containing fraction to at least one of the reaction zones;
and
introducing a light olefinic hydrocarbon fraction to the octane restoration reaction zone to further increase octane and reduce product benzene concentration.

3 more elements

Dependencies are inferred from the claim text.

Gasoline upgrading process

Life of this patent

Gasoline upgrading process

Life of this patent

Abstract

Claims18