Abstract: Hydrocarbon extraction processes utilizing a cleansing bed to cleanse at least a portion of a lean-solvent stream are disclosed. The cleansing bed can preferentially include abed of activated carbon, abed of alumina, and/or a bed of an ion-exchange resin. The extraction process can use a liquid/liquid extraction column or an extraction distillation column. The process can be particularly advantageous for removing C10-C20 contaminants, among others, from the lean-solvent stream.

Abstract: Selective removal of non-aromatic hydrocarbons from a xylene isomerization process for para-xylene production is accomplished using a membrane unit positioned within a xylene recovery loop. The membrane unit may include a one-stage or multi-stage (e.g., two-stage) membrane system and may be configured to separate a membrane unit product stream from a non-aromatics rich stream, which can be removed from the xylene recovery loop. The membrane unit may have a xylene permeance of about 60 gm/m2/hr/psi and a xylene to non-aromatic permeance ratio of about 15.

Abstract: Selective removal of non-aromatic hydrocarbons from a xylene isomerization process for para-xylene production is accomplished using a membrane unit positioned within a xylene recovery loop. The membrane unit may include a one-stage or multi-stage (e.g., two-stage) membrane system and may be configured to separate a membrane unit product stream from a non-aromatics rich stream, which can be removed from the xylene recovery loop. The membrane unit may have a xylene permeance of about 60 gm/m2/hr/psi and a xylene to non-aromatic permeance ratio of about 15.

Abstract: A membrane separator comprising a membrane is used to separate various streams in processes for separating aromatic hydrocarbons from non-aromatic hydrocarbons. Such streams can be a lean-solvent stream, a rich-solvent stream, or a hydrocarbon stream comprising both aromatic and non- aromatic hydrocarbons. The membrane separator is advantageously used in combination with an extraction sub-system including a liquid—liquid distillation column and/or an extraction distillation column.

Abstract: Selective removal of non-aromatic hydrocarbons from a xylene isomerization process for para-xylene production is accomplished using a membrane unit positioned within a xylene recovery loop. The membrane unit may include a one-stage or multi-stage (e.g., two-stage) membrane system and may be configured to separate a membrane unit product stream from a non-aromatics rich stream, which can be removed from the xylene recovery loop. The membrane unit may have a xylene permeance of about 60 gm/m2/hr/psi and a xylene to non-aromatic permeance ratio of about 15.

Abstract: Processes for producing high-octane-number fuel components, particularly those useful for AvGas blends, can be advantageously produced from hydrocarbon feed streams comprising C8+ aromatic hydrocarbons. Such feed streams may be produced by, among others, separation and other optional post-processing of an effluent produced from a steam cracker (e.g., a liquid feed steam cracker cracking liquid feeds such as naphtha and/or other crude fractions, a gas steam cracker cracking gas feeds such as ethane and/or propane), hydrocarbon reforming of a crude fraction or steam cracker effluent fraction, C6-C7 aromatic hydrocarbon methylation, transalkylation between C6-C7 aromatic hydrocarbons and C9+ aromatic hydrocarbons, isomerization of C8 aromatic hydrocarbons, and toluene disproportionation processes.

Abstract: 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.

Abstract: 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.

Abstract: An changeable lead-lag configuration of two isomerization reactors can be used to achieve continuous isomerization operations in an aromatics production complex, even if the isomerization catalyst deactivates over time to require catalyst regeneration and/or replacement. The configuration can be particularly advantageous for two liquid phase isomerization reactors, especially those operated under a high WHSV?5 hour?1 where the isomerization catalyst can deactivate at a high rate.

Abstract: Selective removal of non-aromatic hydrocarbons from a xylene isomerization process for para-xylene production is accomplished using a membrane unit positioned within a xylene recovery loop. The membrane unit may include a one-stage or multi-stage (e.g., two-stage) membrane system and may be configured to separate a membrane unit product stream from a non-aromatics rich stream, which can be removed from the xylene recovery loop. The membrane unit may have a xylene permeance of about 60 gm/m2/hr/psi and a xylene to non-aromatic permeance ratio of about 15.

Abstract: A liquid phase isomerization process comprising cofeeding molecular hydrogen at a feeding rate ?100 ppm by weight can effectively convert a C8 aromatic hydrocarbon isomerization feed in the presence of an isomerization catalyst with a very low deactivation rate of the catalyst, even at high WHSV ?5 hour?1.

Abstract: Methods for the production of para-xylene include flowing a xylenes-containing stream comprising PX, meta-xylene (MX), and ortho-xylene (OX), to a first crystallization stage. In addition, the methods include lowering a temperature of the xylenes-containing stream to below the eutectic point of the xylenes-containing stream within the first crystallization stage to crystallize at least some of the PX and at least some of one of both of the MX and the OX within the xylenes-containing stream. Further, the methods include separating the xylenes-containing stream into a first crystallization effluent stream and a first filtrate stream.

Abstract: 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.

Abstract: 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.

Abstract: 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 C4? olefins. The off-gas stream, containing the C4? olefins, 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.

Abstract: Para-xylene is separated from a mixture of xylenes and ethylbenzene by a separation process. An ortho-selective adsorbent is used to reduce the ortho-xylene concentration of the xylenes, prior to contact of the xylenes and ethylbenzene with a para-selective adsorbent. The stream rich in ortho-xylene may be isomerized in the liquid phase to increase the amount of para-xylene therein. The para-xylene-depleted stream may be treated in the vapor phase to remove the ethylbenzene and then subjected to isomerization in the liquid phase to produce a stream having a higher than equilibrium amount of para-xylene.

Abstract: 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.

Abstract: A hydrocarbon conversion process is described. The process includes contacting in a reactor an inert gas with one or more catalyst compositions suitable for methylation of toluene and hydrogenation of phenol; contacting a reducing agent with the one or more catalyst compositions under conditions suitable for reducing metal oxide content of the catalyst composition; contacting at least part of toluene and/or benzene-containing with a oxygenate in the presence of the one or more catalyst compositions and under conditions effective to convert toluene to xylenes and produce a reactor effluent stream comprising para-xylene and having a lower concentration of phenol than the toluene-containing stream; separating at least one para-xylene-enriched stream from the reactor effluent stream; and separating from the at least one para-xylene enriched stream at least one toluene-enriched stream and at least one para-xylene-product stream. An apparatus for carrying out such a process is also described.

Abstract: 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.

Abstract: 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 ?5, and the alkylation conditions comprise a temperature less than 500° 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.