Mobil Oil Corporation

Lloyd L Breckenridge

David Lawrence Stern

Jeffrey S Beck

Albin Huss, Jr

Garry W Kirker

Albert B Schwartz

Ajit V Sapre

Kenneth J Del Rossi

Chaya R Venkat

Clinton R Kennedy

Fritz A Smith

Robert G Bundens

Catherine L Markham

Diane V Jorgensen

Jeeven S Abichandani

A mixture of aromatic hydrocarbons, comprising ethylbenzene and at least one xylene, is isomerized using a two reactor system to convert the ethylbenzene to compounds that may be removed from the aromatic hydrocarbon stream and to produce a product stream wherein the para-xylene concentration is approximately equal to the equilibrium ratio of the para-isomer. The catalyst present in the first reactor is one that is effective for ethylbenzene conversion with minimal xylene loss when operated under suitable conversion conditions, e.g., a catalyst comprising silica bound ZSM-5 that has been selectivated by one or more silicon impregnations or that has been coke selectivated. The catalyst present in the second reactor is one which is effective to catalyze xylene isomerization when operated under suitable conditions. Each of the catalysts of this invention may contain one or more hydrogenation or dehydrogenation components.

Xylene isomerization on separate reactors

There is provided a process for ring opening of aromatics and cycloaliphatics, as well as isomerization of aliphatics. The feedstream to this process comprises hydrocarbons having 6 carbon atoms. The process involves the use of at least two reactors connected in series. The first reactor comprises a zeolite catalyst and is operated under conditions which particularly promote ring opening. The catalyst in this first reactor may comprise zeolite Beta and platinum. A downstream reactor is operated under conditions to promote isomerization of aliphatics. The catalyst in the second reactor may comprise alumina, platinum and a chloride component. Hydrogen in the effluent of the first reactor may be removed and recycled to the first reactor. Hydrogen required for the second reactor may be satisfied by hydrogen remaining dissolved in the effluent from the first reactor after hydrogen is recycled to the first reactor.

Combined paraffin isomerization/ring opening process

A process for reducing the benzene content of a reformate stream in a conventional catalytic cracking reactor wherein a heavy hydrocarbon feed is cracked to lighter products by contact with a supply of hot regenerated cracking catalyst is disclosed. The reformate can be mixed with the heavy feed to the cracking reactor, but preferably reformate contacts hot regenerated cracking catalyst before the heavy feed is added. Benzene content is reduced by alkylation with reactive fragments created in the cracking reactor, or by transalkylation with alkyl aromatics. Benzene removal can be enhanced by adding a light reactive gas such as ethylene to the cracking reactor, by adding heavier aromatics, such as a light cycle oil, or both. The reaction is preferably conducted in an FCC riser reactor, but may be conducted in a moving bed cracking reactor.

Reduction of benzene content of reformate in a catalytic cracking unit

A dual-mode hydrocarbon conversion process is provided which comprises reforming a sulfur-, nitrogen- and/or olefin-containing hydrocarbon feedstock, e.g. an FCC gasoline, in a conversion unit operated under reforming conditions employing as catalyst a noble metal-containing crystalline silicate having a Constraint Index of not greater than about 2 and a framework SiO.sub.2 /Al.sub.2 O.sub.3 ratio of at least about 50 to provide a relatively high yield of high octane reformate and a relatively low yield of C.sub.3-4 hydrocarbons prior to or following hydrocracking the feedstock in the unit operated under hydrocracking conditions in the presence of the aforesaid catalyst to provide a relatively low yield of high octane hydrocrackate and a relatively high yield of C.sub.3-4 hydrocarbons. The latter can be separated from the liquid product and processed in a gas plant to provide LPG products. The dual-mode process of this invention offers the refiner increased flexibility in meeting rapidly fluctuating changes in demand for high octaine gasoline and LPG products.

Dual mode hydrocarbon conversion process

An improved process is provided for catalytic isomerization of monocyclic methyl-substituted aromatic hydrocarbon compounds of from 8 to 10 carbon atoms contained in a feedstock also containing ethylbenzene in a reaction zone maintained under conditions such that said isomerization is accomplished in the vapor phase. The catalyst for the process contains zeolite characterized by a constraint index, hereinafter defined, within the approximate range of 1 to 12. The improvement in the process comprises contacting the catalyst, in situ, with one or more basic nitrogen compounds or precursors thereof.

Isomerization process

Recovery of valuable components from eight carbon atom (C.sub.8) aromatic fractions is enhanced by high temperature processing of C.sub.9.sup.+ aromatics produced by side reactions during isomerization of a C.sub.8 aromatics fraction lean in p-xylene and resulting from separation of that isomer from a mixture of the three xylene isomers and ethyl benzene.

Growing community of inventors

Philadelphia, PA, United States of America

Lloyd L Breckenridge