Exxonmobil Chemical Patents Inc.

Exxonmobil Chemicals Patents, Inc.

Jeffrey L Andrews

Michel Molinier

Robert G Tinger

Timothy Paul Bender

Dennis J Stanley

George J Wagner

Jeevan Sahib Abichandani

Paul Podsiadlo

Chunshe J Cao

Hari Nair

Kathleen M Keville

Todd E Detjen

Xiaobo Zheng

Travis Sparks

Jesus A Ramos

A transalkylation process co-feeds benzene at a relatively high proportion with C9+ aromatics in a feed stream to a transalkylation reactor. At lower proportions (&#x2264;5 wt %) of benzene, ring loss is greater for benzene than toluene and ring loss is increased by increasing the proportion of benzene in the feed stream. When the benzene is co-fed in a proportion sufficiently greater than 5 weight percent of the feed stream, ring loss is unexpectedly reduced.

Transalkylation with reduced ring loss

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

Disclosed is a transalkylation process for making an aromatic material between a light aromatic material and a heavier aromatic material in the presence of hydrogen and a transalkylation catalyst comprising a hydrogenation component and a transalkylation component. The process comprises conducting the transalkylation reaction under conditions conducive to reducing the amount of cyclic compounds in the transalkylation reaction mixture in the beginning phase of the operation that is different from the conditions after the beginning phase. The invention is useful, e.g., in transalkylation between toluene and C9+ aromatic feed materials to produce xylenes and/or benzene.

Transalkylation process

A process is provided for producing xylene by transalkylation including introducing sulfur into a reactor containing a catalyst system prior to first introduction of hydrocarbon feedstock into the reactor; introducing hydrocarbon feedstock into the reactor upon the concentration of sulfur downstream of the catalyst system meeting a predetermined sulfur breakthrough concentration; continuing sulfur introduction for a period of time after first introducing hydrocarbon feedstock into the reactor; reducing the concentration of sulfur introduced upon &#x394;T decreasing to or below a predetermined sulfur reduction threshold; and discontinuing sulfur introduction upon &#x394;T decreasing to or below a predetermined sulfur shutoff threshold.

Sulfiding process for aromatic transalkylations

In a process for producing para-xylene, a feed stream comprising Caromatic hydrocarbons is separated into a toluene-containing stream, a Caromatic hydrocarbon-containing stream and a Caromatic hydrocarbon-containing stream. The toluene-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Para-xylene is recovered from the Caromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C-containing stream with a transalkylation catalyst under conditions effective to convert C-aromatics to C-aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

Apparatus for the production of xylenes

In a process for producing para-xylene, a toluene-containing stream is contacted with a methylating agent under conditions effective to convert toluene to xylenes and produce a methylated effluent stream. Para-xylene is recovered from the methylated effluent stream to produce a para-xylene depleted stream and part of the para-xylene depleted stream is contacted with a xylene isomerization catalyst under liquid phase isomerization conditions effective to produce a first isomerized stream, while part of the para-xylene depleted stream is contacted with a xylene isomerization catalyst under vapor phase isomerization conditions effective to produce a second isomerized stream. The first and second isomerized streams are then recycled to the para-xylene recovery step.

Process for the production of xylenes

In a process for producing para-xylene, a feed stream comprising Caromatic hydrocarbons is separated into a Caromatic hydrocarbon-containing stream, a Caromatic hydrocarbon-containing stream, and a Caromatic hydrocarbon-containing stream. The Caromatic hydrocarbon-containing stream is contacted with a methylating agent to convert toluene to xylenes and produce a methylated effluent stream. Ethylbenzene is removed from the Caromatic hydrocarbon-containing stream, para-xylene is recovered from the ethylbenzene-depleted Caromatic hydrocarbon-containing stream and the methylated effluent stream in a para-xylene recovery section to produce a para-xylene depleted stream, which is then contacted with a xylene isomerization catalyst under liquid phase conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream. The C-containing stream with a transalkylation catalyst under conditions effective to convert C-aromatics to C-aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

The invention relates to minimizing ammonia poisoning of a catalyst and to a xylene isomerization process using said catalyst.

Manufacturing process

The process concerns ethylbenzene conversion and xylene isomerization with a catalyst pretreated by sulfiding.

Growing community of inventors

Houston, TX, United States of America

Jeffrey L Andrews