Mobil Oil Corporation

Other

Mobile Oil Corporation

Timothy L Hilbert

David L Fletcher

Stuart S Shih

Michael S Sarli

Stephen J McGovern

Jeffrey C Trewella

Paul P Durand

Nick Allen Collins

Gerald J Teitman

David A Pappal

Mohsen N Harandi

Stephen Harold Brown

Randall D Partridge

William S Borghard

Thomas R Kiliany, Jr

John E Sauer

Michael G Hunter

Kenneth W Goebel

Chang-Kuei Lee

Michael J Dolan

Arthur R Gentry

David W Rumsey

Michel S Sarli

Douglas S Diez

John D Snyder

This invention relates to the refining of petroleum products, and more particularly to an integrated hydroprocessing scheme involving a hydrocracking stage and subsequent dewaxing stage. Materials boiling in the middle distillate or lube oil range may be dewaxed. The bottoms streams (and optionally, other streams) of each stage are maintained separately from one another, during processing. Dewaxing may occur using either hydroisomerization catalysts or shape-selective catalysts or both in series. One embodiment employs a baffle in the flash zone of a fractionator to separate bottoms streams from each other. Alternatively, the effluent from the hydrocracking stage may be processed separately from the effluent from the dewaxing stage. The bottoms fraction from the dewaxing stage may be recycled back to the hydrocracking stage for further processing or used as lube base stock.

Integrated hydroprocessing scheme with segregated recycle

Low sulfur gasoline is produced from an olefinic, cracked, sulfur-containing naphtha by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5 to crack low octane paraffins and olefins under mild conditions with limited aromatization of olefins and naphthenes. A benzene-rich co-feed is co-processed with the naphtha to reduce the benzene levels in the co-feed by alkylation. This initial processing step is followed by hydrodesulfurization over a hydrotreating catalyst such as CoMo on alumina. In addition to reducing benzene levels in the combined feeds, the initial treatment over the acidic catalyst removes the olefins which would otherwise be saturated in the hydrodesulfurization, consuming hydrogen and lowering product octane, and converts them to compounds which make a positive contribution to octane. Overall liquid yield is high, typically at least 90 percent or higher. Product aromatics are typically increased by no more than 25 weight percent relative to the combined feeds and may be lower than the feed.

Benzene conversion in an improved gasoline upgrading process

Low sulfur gasoline is produced from an olefinic, cracked, sulfur-containing naphtha by treatment over an acidic catalyst, preferably an intermediate pore size zeolite such as ZSM-5 to crack low octane paraffins and olefins under relatively mild conditions, with limited aromatization of olefins and naphthenes. This is followed by hydrodesulfurization over a hydrotreating catalyst such as CoMo on alumina. The initial treatment over the acidic catalyst removes the olefins which would otherwise be saturated in the hydrodesulfurization, consuming hydrogen and lowering product octane, and converts them to compounds which make a positive contribution to octane. Overall liquid yield is high, typically at least 90 percent of higher. Product aromatics are typically increased by no more than 25 weight percent relative to the feed and may be lower than the feed.

Hydrocarbon upgrading process

This invention is a process for the upgrading of distillate feeds. A batch of supported hydroprocessing catalyst is placed in a reaction zone, which is usually a fixed bed reactor. The hydroprocessing catalyst comprises an effective amount of a noble metal or metals and has a specific activity. Both low aromatic diesel and jet fuel may be produced in separate blocks over the same catalyst batch, using different feeds and often different conditions. The activity of the catalyst is restored each time the feed is switched. When production is switched from jet fuel to low aromatics diesel, activity may be regained more quickly by holding the catalyst at a higher temperature than the reaction temperature for a specific period of time prior to dropping the temperature to the reaction temperature. Switching from one feed to the other may continue for about one year before the catalyst batch is changed. A dual catalyst system may alternatively be employed. In this case a hydroprocessing catalyst batch comprising an effective amount of at least one base metal is used in combination with the catalyst comprising an effective amount of at least one noble metal catalyst. The feed contacts the catalyst comprising the base metal before it contacts the catalyst comprising a noble metal. In a dual catalyst system, the feeds may be switched for about two years over the two catalyst batches before fresh catalyst is necessary.

Distillate 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 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 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.

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 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.

Method for measuring particulates in flue gas streams containing chemicals reactive with trace elements in the filters is disclosed which features pretreating the filters with chemicals comparable to those in the process stream whereby the reactions are completed prior to the measurement step, in particular, prior to establishment of the tare weight of said filter.

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Sewell, NJ, United States of America

Timothy L Hilbert