Exxonmobil Chemical Patents Inc.

Todd E Detjen

Robert G Tinger

Paul Podsiadlo

Xiaobo Zheng

Catherine M Dorsi

Jesus A Ramos

Gary David Mohr

Tan-Jen Chen

Scott Jeffrey Weigel

Jeevan Sahib Abichandani

Bhupender S Minhas

Kathleen M Keville

Mayank Shekhar

Timothy Paul Bender

Brett Thomas Loveless

Nikolaos Soultanidis

Jeffrey L Andrews

Anthony Go

Travis Sparks

John S Kennedy

David B Looney

Oluwagbogo Adebayo-Ige

A process and system for separating paraxylene from a mixture of paraxylene, metaxylene, orthoxylene, and ethylbenzene in a simulated moving bed apparatus using a membrane to separate non-aromatics from a desorbent stream. The lower nonaromatics content in the desorbent improves paraxylene product purity, increases paraxylene production at the same desorbent rate, reduces the desorbent rate, and/or reduces energy consumption in the product tower.

Xylene separation processes using a membrane separator

Systems and methods are provided for integration of an aromatic formation process for converting non-aromatic hydrocarbon to an aromatic product and subsequent methylating of a portion of the aromatic product to produce a methylated product, with improvements in the aromatic formation process and/or the methylation process based on integrating portions of the secondary processing trains associated with the aromatic formation process and the methylation process. The aromatic formation process and methylation process can be used, for example, for integrated production of specialty aromatics or gasoline blending components.

Integrated aromatics formation and methylation

Processes for activating precious metal-containing catalysts. The processes can decrease the amount of high purity hydrogen required for starting up a catalytic conversion process such as transalkylation of heavy aromatics, without detrimental impact to the metal activity. The processes can include a low temperature treatment step with a high purity first gas, such as hydrogen generated by electrolysis and/or reformer hydrogen diluted with high purity inert gas, and a high temperature treatment step with a low purity second gas such as the reformer hydrogen. Also, the processes can include mixing a hydrogen gas of high or low purity with a high purity inert gas to form a gas mixture with a proportion of hydrogen no less than 2% and a reduced carbon monoxide concentration relative to the low purity hydrogen, and contacting the catalyst with the gas mixture.

Transalkylation start-up processes for supported precious metal catalyst

Co-feeding sulfolane into a transalkylation reactor along with the aromatic hydrocarbon feed(s) can improve benzene purity of the benzene product stream produced from the transalkylation product mixture, especially at the beginning phase of a catalyst cycle.

Transalkyation processes in the presence of sulfolane

A process for producing paraxylene by the catalytic alkylation of benzene and/or toluene with methanol, which produces a para-rich mixture of xylene isomers, together with water and some light organic by-products, particularly dimethyl ether and C&#x2212; olefins. The off-gas stream, containing the Colefins, may be recycled back to the reaction to be co-injected with methanol to reduce the methanol self-decomposition and the reaction of methanol to olefins or to fluidize catalyst particles recovered by a reactor cyclone. By using recycled off-gas rather than water or steam, the deleterious effects of water and/or steam on the catalyst aging and activity rates and the size of downstream equipment necessary to recover olefin by-products may be reduced.

Use of light gas by-products in the production of paraxylene by the methylation of toluene and or benzene

Disclosed herein is a process for producing para-xylene comprising the steps of: (a) contacting a feedstock comprising toluene with a first catalyst under effective vapor phase toluene disproportionation conditions to disproportionate said toluene and produce a first product comprising benzene, unreacted toluene and greater than equilibrium amounts of para-xylene; and (b) contacting a feedstock comprising Caromatic hydrocarbons and benzene with a second catalyst in the presence of 0 wt. % or more of hydrogen having a 0 to 10 hydrogen/hydrocarbon molar ratio under effective Ctransalkylation conditions to transalkylate said Caromatic hydrocarbons and produce a second product comprising xylenes.

Disproportionation and transalkylation of heavy aromatic hydrocarbons

In a process for producing paraxylene, a hydrocarbon feedstock comprising benzene and/or toluene is contacted with an alkylating reagent comprising methanol and/or dimethyl ether in an alkylation reaction zone under alkylation conditions in the presence of an alkylation catalyst to produce an alkylated product comprising xylenes. The alkylation catalyst comprises a molecular sieve having a Constraint Index &#x2264;5, and the alkylation conditions comprise a temperature less than 500&#xb0; C. At least part of the alkylated product is supplied to a paraxylene recovery unit to recover paraxylene and produce a paraxylene-depleted stream, which is then contacted with a xylene isomerization catalyst under conditions effective to isomerize xylenes in the paraxylene-depleted stream and produce an isomerized stream having a higher concentration of paraxylene than the paraxylene-depleted stream. At least part of the isomerized stream is then recycled to the paraxylene recovery unit to recover the paraxylene therein.

Process for methylating aromatic hydrocarbons

The invention relates to treating a molecular sieve prepared by at least one in situ selectivation sequence wherein graphitic coke is adhered to said molecular sieve, which is useful in a toluene disproportionation process.

In-situ trim coke selectivation of toluene disproportionation catalyst

A fluidized bed process for producing para-xylene via toluene and/or benzene methylation with methanol using a dual function catalyst system. A first catalyst accomplishes the toluene and/or benzene methylation and a second catalyst converts the by-products of the methylation reaction or unconverted methylating agent, improves the yields of the desired products, or a combination thereof. The inclusion of the second catalyst can suppress the C-Cnon-aromatic fraction by over 50% and significantly enhance the formation of aromatics.

Catalyst and process for the production of para-xylene

Methods and related systems are disclosed for condensing a minor portion of an effluent stream from an alkylation reactor by contacting the effluent stream with a first liquid hydrocarbon quench stream and a second liquid hydrocarbon quench stream. The effluent stream includes catalyst fines from the reactor, and at least a portion of the catalyst fines are carried with the condensed minor portion of the effluent stream.

Systems and methods for aromatic alkylation

A method of reducing the amount of carbon monoxide present during the metal reduction step of start-up, thus, maintaining metal dispersion and improving the metal reduction and catalyst yields. Carbon monoxide formation is minimized during the start-up procedure and during the initial catalyst dryout phase in a hydrogen-containing atmosphere, gas is purged from the reactor system, either continuously at constant pressure or by a series of pressure/depressure cycles, to remove carbon monoxide. The purging is conducted at temperatures of about 30-500&#xb0; C. and pressures of about &#x2212;90-5,000 kPa(g) (&#x2212;0.9-50 bar(g)). In this temperature range, carbon monoxide absorbed to the surface of the metal will desorb into the hydrogen-containing atmosphere and can be removed from the system along with carbon monoxide present in the atmosphere through the purging.

Method of improving metal-impregnated catalyst performance

The invention relates to a transalkylation system to convert feedstreams containing benzene and/or toluene (C7&#x2212; aromatic hydrocarbons) and feedstreams containing C9+ aromatic hydrocarbons into a product stream comprising xylenes.

Growing community of inventors

Houston, TX, United States of America

Todd E Detjen