Mobil Oil Corporation

Mobile Oil Corporation

David L Fletcher

Stuart S Shih

Michael S Sarli

Timothy L Hilbert

Stephen J McGovern

Mohsen N Harandi

John E Sauer

Hartley Owen

Daria N Lissy

Nick Allen Collins

Kathleen M Keville

Minas R Apelian

Gerald J Teitman

David A Pappal

Paul P Durand

Edward F Kondis

Douglas S Diez

David W Rumsey

Michel S Sarli

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 a catalyst comprising an intermediate pore size zeolite, such as ZSM-5, and a large pore size zeolite, including a metal hydrogenation function, such as a faujasite, preferably USY, which contains nickel and molybdenum. 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. Use of the intermediate pore size zeolite and the large pore size zeolite is expected to provide more boiling point conversion than either zeolite alone under the same conditions.

Hydrocarbon upgrading process

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 comprising zeolite beta. 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.

Gasoline upgrading process

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 containing, preferably an intermediate pore size zeolite such as ZSM-5 and a zeolite such as MCM-22. 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.

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha by hydrodesulfurization followed by treatment in a second step over a a first catalyst zone comprising a large pore size zeolite material and a second catalyst zone comprising an intermediate pore size material. Preferably, the large pore size material is zeolite beta and the intermediate pore size material is ZSM-5. The treatment 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.

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. 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.

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 under endothermic conditions in a second reaction zone. Heat is added to the endothermic reaction zone to initiate and maintain octane restoring reactions. The preferred acidic catalyst is an intermediate pore size zeolite such as ZSM-5. 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. The addition of heat at the second zone prolongs hydrodesulfurization catalyst life by allowing a lower hydrodesulfurization reactor temperature. The addition of heat also maximizes octane increase in the second zone.

Low sulfur gasoline of relatively high octane number is produced from a catalytically cracked, sulfur-containing naphtha and benzene-rich fraction by hydrodesulfurization in a first reaction zone and treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5 in a second reaction zone to reduce the octane loss which takes place as a result of the hydrodesulfurization. The benzene-rich fraction can be cofed to the first reaction zone or the second reaction zone. The benzene-rich fraction is preferably a heart-cut reformate.

Low sulfur gasoline is produced from a catalytically cracked, sulfur-containing naphtha by fractionating the naphtha feed into a low boiling fraction in which the majority of the sulfur is present in the form of mercaptans and a high-boiling fraction in which the sulfur is predominantly in non-mercaptan form such as thiophenes. The low boiling fraction is desulfurized by a non-hydrogenative mercaptan extraction process which retains the olefins which are present in this fraction. The second fraction is desulfurized by hydrodesulfurization, which results in some saturation of olefins and loss of octane. The octane loss is restored by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5, to form a low sulfur gasoline product with an octane number comparable to that of the feed naphtha but which contains some recombined sulfur in the form or mercaptans which are removed in the non-hydrogenative mercaptan extraction step.

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 defined by its x-ray diffraction pattern and preferably comprising the synthetic zeolite MCM-22. 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.

A process for producing a desulfurized gasoline boiling range product of relatively high octane number from a sulfur containing feed boiling in the naphtha boiling range by converting the feed in a first stage over a conventional hydrodesulfurization catalyst, and then converting at least the normally liquid portion of the product of this first stage conversion over a catalyst comprising a zeolitic behaving refractory solid having acid activity and shape selectivity to produce a product having a sulfur content within the required specifications, and an octane number which at least approaches the octane number of the feed.

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.

A sulfur-containing catalytically cracked naphtha is upgraded to form a low-sulfur gasoline product by a process which retains the octane contribution from the olefinic front end of the naphtha. Initially, the mercaptan sulfur in the front end of the cracked naphtha is converted to higher boiling disulfides by oxidation. The front end, which is then essentially an olefinic, high octane sulfur-free material, may be blended directly into the gasoline pool. The back end, which now contains the original higher boiling sulfur components such as thiophenes, together with the sulfur transferred from the front end as disulfides, is hydrotreated to produce a desulfurized product. This desulfurized product, which has undergone a loss in octane by saturation of olefins, is then treated in a second stage, by contact with a catalyst of acidic functionality, preferably a zeolite such as ZSM-5, under conditions which produce a product in the gasoline boiling range of higher octane value. Because this second product may contain combined organic sulfur, it may be subjected to a final desulfurization to reduce organic sulfur to acceptable levels.

Low sulfur gasoline is produced from a catalytically cracked, sulfur-containing naphtha by fractionating the naphtha feed into a low boiling fraction in which the majority of the sulfur is present in the form of mercaptans and a high-boiling fraction in which the sulfur is predominantly in non-mercaptan form such as thiophenes. The low boiling fraction is desulfurized by a non-hydrogenatile mercaptan extraction process which retains the olefins present in this fraction. The second fraction is desulfurized by hydrodesulfurization, which results in some saturation of olefins and loss of octane. The octane loss is restored by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5, to form a low sulfur gasoline product with an octane number comparable to that of the feed naphtha but which contains some recombined sulfur in the form or mercaptans which are removed in a final hydrotreatment.

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, modified to reduce surface acidity, and preferably an intermediate pore size zeolite such as ZSM-5. 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.

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 comprising 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 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. The use of the specified zeolite provides greater desulfurization, gasoline selectivity, and octane than obtained using ZSM-5.

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Turnersville, NJ, United States of America

David L Fletcher