Abstract: 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 (?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.

Abstract: Methods are provided for activation of catalysts comprising low amounts of a hydrogenation metal, such as low amounts of a Group 8-10 noble metal. The amount of hydrogenation metal on the catalyst can correspond to 0.5 wt % or less (with respect to the weight of the catalyst), or 0.1 wt % or less, or 0.05 wt % or less. Prior to loading a catalyst into a reactor, the corresponding catalyst precursor can be first activated in a hydrogen-containing atmosphere containing 1.0 vppm of CO or less. The thus first-activated catalyst can be transferred to a reactor with optional exposure to oxygen during the transfer, where it can be further activated using a hydrogen-containing atmosphere containing 3.0 vppm of CO or higher, to yield a twice-activated catalyst with high performance. The catalyst can be advantageously a transalkylation catalyst or an isomerization catalyst useful for converting aromatic hydrocarbons.

Abstract: A process and related system for producing para-xylene (PX). In an embodiment, the process includes (a) separating a feed stream comprising C6+ aromatic hydrocarbons into a toluene containing stream and a C8+ hydrocarbon containing stream and (b) contacting at least part of the toluene containing stream with a methylating agent in a methylation unit to convert toluene to xylenes and produce a methylated effluent stream. In addition, the process includes (c) recovering PX from the methylated effluent stream in (b) to produce a PX depleted stream and (d) transalkylating the PX depleted stream to produce a transalkylation effluent stream. The transalkylation effluent stream includes a higher concentration of toluene than the PX depleted stream. Further, the process includes (e) converting at least some ethylbenzene (EB) within the C8+ hydrocarbon containing stream into toluene and (f) flowing the toluene converted in (e) to the contacting in (b).

Abstract: Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

Abstract: Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

Abstract: 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 (?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.

Abstract: Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

Abstract: A process and related system for producing para-xylene (PX). In an embodiment, the process includes (a) separating a feed stream comprising C6+ aromatic hydrocarbons into a toluene containing stream and a C8+ hydrocarbon containing stream and (b) contacting at least part of the toluene containing stream with a methylating agent in a methylation unit to convert toluene to xylenes and produce a methylated effluent stream. In addition, the process includes (c) recovering PX from the methylated effluent stream in (b) to produce a PX depleted stream and (d) transalkylating the PX depleted stream to produce a transalkylation effluent stream. The transalkylation effluent stream includes a higher concentration of toluene than the PX depleted stream. Further, the process includes (e) converting at least some ethylbenzene (EB) within the C8+ hydrocarbon containing stream into toluene and (f) flowing the toluene converted in (e) to the contacting in (b).

Abstract: Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

Abstract: Alkyl-demethylation of C2+-hydrocarbyl substituted aromatic hydrocarbons can be utilized to treat one or more of a heavy naphtha reformate stream, a hydrotreated SCN stream, a C8 aromatic hydrocarbon isomerization feed stream, a C9+ aromatic hydrocarbon transalkylation feed stream, and similar hydrocarbon streams to produce additional quantity of xylene products.

Abstract: 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.

Abstract: Methods are provided for activation of catalysts comprising low amounts of a hydrogenation metal, such as low amounts of a Group 8-10 noble metal. The amount of hydrogenation metal on the catalyst can correspond to 0.5 wt % or less (with respect to the weight of the catalyst), or 0.1 wt % or less, or 0.05 wt % or less. Prior to loading a catalyst into a reactor, the corresponding catalyst precursor can be first activated in a hydrogen-containing atmosphere containing 1.0 vppm of CO or less. The thus first-activated catalyst can be transferred to a reactor with optional exposure to oxygen during the transfer, where it can be further activated using a hydrogen-containing atmosphere containing 3.0 vppm of CO or higher, to yield a twice-activated catalyst with high performance. The catalyst can be advantageously a transalkylation catalyst or an isomerization catalyst useful for converting aromatic hydrocarbons.

Abstract: A process and catalyst system is disclosed for producing para-xylene from a C8 hydrocarbon mixture comprising ethylbenzene and at least one xylene isomer other than para-xylene. The process modifies the conventional process by operating with a higher weight hourly space velocity, lower pressure and lower hydrogen partial pressure, which allows production of on-specification benzene product without penalty with respect to ethylbenzene conversion, para-xylene approach to equilibrium or xylene losses. The catalyst system comprises a first catalyst bed comprising a first zeolite having a constraint index from 1 to 12 and an average crystal size from 0.1 to 1 micron and a platinum hydrogenation component, and a second catalyst bed comprising a second zeolite having a constraint index ranging from 1 to 12 and an average crystal size of less than 0.1 micron and a rhenium hydrogenation component.

Abstract: In a process for producing para-xylene, at least one feed comprising C6+ aromatic hydrocarbons is supplied to a dividing wall distillation column to separate the feed into a C7? aromatic hydrocarbon-containing stream, a C8 aromatic hydrocarbon-containing stream and a C9+ aromatic hydrocarbon-containing stream. At least part of the C8 aromatic hydrocarbon-containing stream is then supplied to a para-xylene recovery unit to recover para-xylene from the C8 aromatic hydrocarbon-containing stream and produce a para-xylene depleted stream. The para-xylene depleted stream is contacted with a xylene isomerization catalyst in a xylene isomerization zone under conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream, which is then at least partially recycled to the para-xylene recovery unit.

Abstract: The present invention is an improved process and apparatus for producing para-xylene, particularly with respect to a process that involves the methylation of toluene and/or benzene to selectively produce para-xylene, wherein streams having differing amounts of ethylbenzene are separately treated in the recovery of para-xylene. A first hydrocarbon feed comprising xylenes and ethylbenzene is provided to a first para-xylene adsorption section, and a second hydrocarbon feed comprising xylenes and less EB than the first hydrocarbon feed is provided to a second para-xylene adsorption section. Segregating the feeds with differing ethylbenzene contents increases the overall efficiency of the adsorption of para-xylene by the adsorption units. Efficiency and energy savings may be further improved by subjecting the lower-content ethylbenzene stream to liquid phase isomerization.

Abstract: In a process for producing para-xylene, at least one feed comprising C6+ aromatic hydrocarbons is supplied to a dividing wall distillation column to separate the feed into a C7? aromatic hydrocarbon-containing stream, a C8 aromatic hydrocarbon-containing stream and a C9+ aromatic hydrocarbon-containing stream. At least part of the C8 aromatic hydrocarbon-containing stream is then supplied to a para-xylene recovery unit to recover para-xylene from the C8 aromatic hydrocarbon-containing stream and produce a para-xylene depleted stream. The para-xylene depleted stream is contacted with a xylene isomerization catalyst in a xylene isomerization zone under conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream, which is then at least partially recycled to the para-xylene recovery unit.

Abstract: In a process for producing para-xylene, a feed stream comprising C6+ aromatic hydrocarbons is separated into a toluene-containing stream, a C8 aromatic hydrocarbon-containing stream and a C9+ aromatic 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 C8 aromatic 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 C9+-containing stream with a transalkylation catalyst under conditions effective to convert C9+-aromatics to C8?-aromatics and produce a transalkylated stream, which is recycled together with the isomerized stream to the para-xylene recovery section.

Abstract: In a process for producing para-xylene, at least one feed comprising C6+ aromatic hydrocarbons is supplied to a dividing wall distillation column to separate the feed into a C7? aromatic hydrocarbon-containing stream, a C8 aromatic hydrocarbon-containing stream and a C9+ aromatic hydrocarbon-containing stream. At least part of the C8 aromatic hydrocarbon-containing stream is then supplied to a para-xylene recovery unit to recover para-xylene from the C8 aromatic hydrocarbon-containing stream and produce a para-xylene depleted stream. The para-xylene depleted stream is contacted with a xylene isomerization catalyst in a xylene isomerization zone under conditions effective to isomerize xylenes in the para-xylene depleted stream and produce an isomerized stream, which is then at least partially recycled to the para-xylene recovery unit.

Abstract: A process and catalyst system is disclosed for producing para-xylene from a C8 hydrocarbon mixture comprising ethylbenzene and at least one xylene isomer other than para-xylene. The process modifies the conventional process by operating with a higher weight hourly space velocity, lower pressure and lower hydrogen partial pressure, which allows production of on-specification benzene product without penalty with respect to ethylbenzene conversion, para-xylene approach to equilibrium or xylene losses. The catalyst system comprises a first catalyst bed comprising a first zeolite having a constraint index from 1 to 12 and an average crystal size from 0.1 to 1 micron and a platinum hydrogenation component, and a second catalyst bed comprising a second zeolite having a constraint index ranging from 1 to 12 and an average crystal size of less than 0.1 micron and a rhenium hydrogenation component.

Abstract: The present invention is an improved process and apparatus for producing para-xylene, particularly with respect to a process that involves the methylation of toluene and/or benzene to selectively produce para-xylene, wherein streams having differing amounts of ethylbenzene are separately treated in the recovery of para-xylene. A first hydrocarbon feed comprising xylenes and ethylbenzene is provided to a first para-xylene adsorption section, and a second hydrocarbon feed comprising xylenes and less EB than the first hydrocarbon feed is provided to a second para-xylene adsorption section. Segregating the feeds with differing ethylbenzene contents increases the overall efficiency of the adsorption of para-xylene by the adsorption units. Efficiency and energy savings may be further improved by subjecting the lower-content ethylbenzene stream to liquid phase isomerization.