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 method of recovering paraxylene in a crystallization zone. The crystallization zone includes at least two crystallization stages and two reslurry stages. The method provides for lower throughput through the crystallization zone, resulting in lower capital costs, reduced electricity in operating separation equipment, as well as reduced refrigeration duty.

Abstract: The present disclosure relates to a method for a simulated moving bed to adsorb and separate polycyclic aromatic hydrocarbons. Zeolite, metal oxide and metal-modified materials are employed as adsorbent. Firstly, diesel oil flows through pre-treatment adsorbent to remove the trace amount of impurities. Secondly, the purified diesel oil flows through the simulated moving bed so that the PAHs can be separated from diesel oil. In this process, the valves are switched periodically, leading to the relative movement of adsorption beds. At the same time, desorbent is pumped into the equipment to wash out PAHs, achieving the continuous adsorption-regeneration operation. Thirdly, simple distillation is employed to separate desorbent from clean diesel oil and PAHs, respectively. Finally, the fractions of clean diesel oil and PAHs can be obtained, respectively. The separated desorbent can be recycled. The PAHs removal rate can reach to 90%.

Abstract: Processes for recovering paraxylene from at least two feedstreams containing xylene isomers. The process includes directing to a paraxylene recovery zone comprising at least one crystallization zone, a paraxylene-lean feedstream having a paraxylene to total xylene isomer ratio of 0.50 or less, and also directing to the paraxylene recovery zone, a paraxylene-rich feedstream having a paraxylene to total xylene isomer ratio of greater than 0.50. A paraxylene-containing product stream is recovered from the paraxylene recovery zone having a paraxylene to total xylene isomer ratio greater than that of the paraxylene-rich feedstream. The process provides improvements in paraxylene recovery efficiency and/or cost effectiveness.

Abstract: Methods and systems for the dehydrogenation of hydrocarbons include a direct contact condenser to remove compounds from an offgas process stream. The reduction of compounds can decrease duty on the offgas compressor by removing steam and aromatics from the offgas. The dehydrogenation reaction system can be applicable for reactions such as the dehydrogenation of ethylbenzene to produce styrene, the dehydrogenation of isoamiline to produce isoprene, or the dehydrogenation of n-pentene to produce piperylene.

Abstract: A feedstream comprising paraxylene and styrene is contacted, in the presence of hydrogen, with a catalyst comprising at least one metal, selected from one or more metals selected from Groups 8-10.

Abstract: The present invention describes a novel configuration for simulated counter-current para-xylene production units, constituted by two adsorbers, characterized in that the volume occupied by the solid adsorbent is reduced by at least 8% compared with the volume of solid adsorbent contained in the adsorbers of a prior art unit. This novel configuration can be used to minimize the quantity of solid adsorbent necessary to produce a given quantity of para-xylene.

Abstract: A process for reforming a hydrocarbon stream is presented. The process involves splitting a naphtha feedstream to at least two feedstreams and partially processing each feedstream in separate reactors. The processing includes passing the light stream to a combination hydrogenation/dehydrogenation reactor. The process reduces the energy by reducing the endothermic properties of intermediate reformed process streams.

Abstract: A process for reforming a hydrocarbon stream is presented. The process involves splitting a naphtha feedstream to at least two feedstreams and partially processing each feedstream in separate reactors. The processing includes passing the light stream to a combination hydrogenation/dehydrogenation reactor. The process reduces the energy by reducing the endothermic properties of intermediate reformed process streams.

Abstract: A process for reforming hydrocarbons is presented. The process involves applying process controls over the reaction temperatures to preferentially convert a portion of the hydrocarbon stream to generate an intermediate stream, which will further react with reduced endothermicity. The intermediate stream is then processed at a higher temperature, where a second reforming reactor is operated under substantially isothermal conditions.

Abstract: A process is presented for the increasing the yields of aromatics from reforming a hydrocarbon feedstream. The process includes splitting a naphtha feedstream into a light hydrocarbon stream, and a heavier stream having a relatively rich concentration of naphthenes. The heavy stream is reformed to convert the naphthenes to aromatics and the resulting product stream is further reformed with the light hydrocarbon stream to increase the aromatics yields. The catalyst is passed through the reactors in a sequential manner.

Abstract: A process for the production of aromatics through the reforming of a hydrocarbon stream is presented. The process utilizes the differences in properties of components within the hydrocarbon stream to increase the energy efficiency. The differences in the reactions of different hydrocarbon components in the conversion to aromatics allows for different treatments of the different components to reduce the energy used in reforming process.

Abstract: A process according to various approaches includes flushing an intermediate transfer line between a raffinate stream transfer line and a desorbent stream transfer line away from the adsorptive separation chamber to remove residual fluid including desorbent from intermediate transfer line. The process may include directing the residual fluid flushed from the intermediate transfer line to a recycle stream to introduce the residual fluid into the adsorptive separation chamber.

Abstract: Methods and systems are provided for producing a desired xylene isomer. The method includes adsorbing the desired xylene isomer from a mixed xylene stream in an adsorbent chamber. The desired xylene isomer is desorbed with a desorbent to produce an extract stream with the desired xylene isomer and the desorbent, where the desorbent has a lower boiling point than the desired xylene isomer. The extract stream is fractionated in an extract fractionator to produce a low pressure extract overhead stream with gaseous desorbent. The low pressure extract overhead stream is pressurized to produce a high pressure extract overhead stream with a temperature greater than an extract reboiler temperature.

Abstract: Apparatuses and methods are provided for forming C8 aromatic streams with selected amounts of C9 aromatics. In one embodiment, a method for forming a C8 aromatic stream with a selected amount of C9 aromatics includes fractionating a hydrocarbon stream including C8 and C9 aromatics into a sidedraw fraction and a bottom fraction. The sidedraw fraction includes a portion of the C8 aromatics and a portion of the C9 aromatics. The bottom fraction includes remaining C8 aromatics and C8+ hydrocarbons. The method further includes fractioning the bottom fraction and forming a heavy overhead fraction including the remaining C8 aromatics. Also, the method includes combining the sidedraw fraction and the heavy overhead fraction to form a combined stream having a C9 aromatics composition of from about 0.1 wt % to about 5 wt % about 2 wt % of a total weight of the combined stream.

Abstract: Apparatuses and methods are provided for isolating C8 aromatics from hydrocarbon streams. In one embodiment, a method for separating C8 aromatics from a hydrocarbon stream includes introducing the hydrocarbon stream to a fractionation column at a feed point. Further, the method includes fractionating the hydrocarbon stream in the fractionation column. Also, the method includes withdrawing a sidedraw fraction from the fractionation column at a draw point located above the feed point, wherein the sidedraw fraction includes C8 aromatics.

Abstract: An aromatics complex producing one or more xylene isomers offers a large number of opportunities to conserve energy by heat exchange within the complex. One previously unrecognized opportunity is through providing two parallel distillation columns operating at different pressures to separate C8 aromatics from C9+ aromatics. The parallel columns offer additional opportunities to conserve energy within the complex through heat exchange in associated xylene recovery facilities.

Abstract: Methods and systems for separating para-xylene are disclosed. In one exemplary embodiment, a method for separating para-xylene includes the steps of providing a feed stream including para-xylene and other C8 aromatic hydrocarbons to a first adsorbent bed within a radial flow simulated moving bed chamber and providing a desorbent stream to a second bed within the radial flow simulated moving bed chamber. The method further includes circulating the feed stream and the desorbent stream radially within the radial flow simulated moving bed chamber to third and fourth beds within the radial flow simulated moving bed chamber. Still further, the method includes withdrawing an extract stream including the para-xylene from the third bed and withdrawing a raffinate stream including the other C8 aromatic hydrocarbons from the fourth bed.

Abstract: The present invention relates to a method and system for recovering aromatics from a naphtha feedstock obtained from a crude petroleum, natural gas condensate, or petrochemical feedstock. The method and system comprise the steps of recovering an aromatics fraction from the feedstock prior to reforming.

Abstract: An aromatics complex producing one or more xylene isomers offers a large number of opportunities to conserve energy by heat exchange within the complex. One previously unrecognized opportunity is through providing two parallel distillation columns operating at different pressures to separate C8 aromatics from C9+ aromatics. The parallel columns offer additional opportunities to conserve energy within the complex through heat exchange in associated xylene recovery facilities.

Abstract: A process for separating para-xylene from a plurality of xylene isomers, wherein the process introduces at a first feed point a first mixed xylene stream comprising a plurality of xylene isomers into a first adsorptive separation unit to produce a first para-xylene enriched stream and a first raffinate stream, and introduces a second mixed xylene stream comprising a plurality of xylene isomers into a second adsorptive separation unit to produce a second raffinate stream. The process feeds both the first raffinate stream and the second raffinate stream into a raffinate column. The process further introduces an extract stream from the second adsorptive separation unit into a first input of a split extract column comprising an internal partition defining a first distillation zone and a second distillation zone.

Abstract: An aromatics complex producing one or more xylene isomers offers a large number of opportunities to conserve energy by heat exchange within the complex. One previously unrecognized opportunity is through providing two parallel distillation columns operating at different pressures to separate C8 aromatics from C9+ aromatics. The parallel columns offer additional opportunities to conserve energy within the complex through heat exchange in associated xylene recovery facilities.

Abstract: An apparatus includes a first distillation apparatus for obtaining a fraction enriched in C8+ aromatics; a second distillation apparatus for obtaining a fraction enriched in C8 aromatics; an adsorption separation apparatus for obtaining an extract containing para-xylene and a raffinate containing xylene isomers; a third distillation apparatus for obtaining a fraction enriched in para-xylene; and a fourth distillation apparatus for obtaining a fraction enriched in xylene isomers. The second distillation apparatus includes a high-pressure part including a rectifying section; a low-pressure part including a stripping section; a line for directing overhead vapor of the low-pressure part to a column bottom of the high-pressure part; a line for directing a column bottom liquid of the high-pressure part to a column top of the low-pressure part; and a heat exchange structure for transferring heat from the rectifying section to the stripping section.

Abstract: Methods and apparatuses for separating toluene from multiple hydrocarbon streams are provided. A method includes fractionating a first hydrocarbon stream, which includes benzene-depleted fractionation bottoms from benzene fractionation, in a first fractionation zone into a first fractionation overhead stream that includes toluene and a first fractionation bottoms. A second hydrocarbon stream, which includes toluene and is substantially free of compounds having a higher vapor pressure than toluene, is fractionated in a second fractionation zone into a second fractionation overhead stream including toluene and a second fractionation bottoms. The second fractionation zone is in liquid isolation from and in vapor communication with the first fractionation zone. The first fractionation bottoms are removed from the first fractionation zone, and the second fractionation bottoms are removed from the second fractionation zone separate from the first fractionation bottoms.

Abstract: The present invention describes a novel configuration for simulated counter-current para-xylene production units, constituted by two adsorbers, characterized in that the volume occupied by the solid adsorbent is reduced by at least 8% compared with the volume of solid adsorbent contained in the adsorbers of a prior art unit. This novel configuration can be used to minimize the quantity of solid adsorbent necessary to produce a given quantity of para-xylene.

Abstract: The invention relates to a method for extracting styrene, having a polymerization quality, from pyrolysis benzol fractions containing styrene by means of extractive distillation. The pyrolysis benzol fraction is separated in a separating wall column in a C8-core fraction, a C7 fraction and a C9+-fraction, the obtained C8-core fraction is subjected to selective hydrogenation of the phenylacetylene C8H6 which it contains. Subsequently, the obtained C8-fraction undergoes extractive-distillative separation in a styrene fraction and a fraction which is low in styrene.

Abstract: Methods and systems for controlling the pressure of distillation columns, for example those operating under vacuum pressure and conventionally equipped with a steam ejector system, are described. Representative distillation columns are used in the separation of thermally unstable components, such as the physical solvent sulfolane, having relatively low volatility. Such columns are employed in aromatic hydrocarbon extraction processes for the recovery of purified C6-C8 aromatic hydrocarbons from a hydrocarbon feed stream (e.g., obtained from the catalytic reforming of naphtha).

Abstract: A process for maximizing p-xylene production begins by producing a naphtha fraction and a light cycle oil fraction from a fluid catalytic cracking zone. The gasoline and light cycle oil fractions are combined and hydrotreated to produce a hydrotreated product. Fractionation of the hydrotreated product in a fractionation zone makes a light ends cut, a naphtha cut, a hydrocracker feed and an unconverted oil fraction. The hydrocracker feed is sent to a hydrocracking zone to make a hydrocracker product, which is then recycled back to the fractionation zone, feeding the hydrocracker product above an outlet for the hydrocracker feed, but below an outlet for the naphtha cut. The naphtha cut goes to a dehydrogenation zone where hydrogen is removed to make aromatics from naphthenes to make a dehydrogenated naphtha. The dehydrogenated naphtha is fed to an aromatics recovery unit to recover p-xylene and other aromatics.

Abstract: A reforming process includes integrating catalytic cracking product naphtha dehydrogenation and naphtha from a hydrocracking zone and feeding them to a dehydrogenation zone. The dehydrogenation zone includes a first portion of reforming catalyst from a catalyst regenerator that moves downward through the dehydrogenation zone. A product stream from the dehydrogenation zone flows to an aromatics unit and is separated into an aromatic-rich extract and a raffinate. Straight run naphtha and the raffinate are introduced to a first reforming zone that includes a second portion of reforming catalyst. The reforming catalyst moves through the first reforming zone then is removed from the bottom of each of the first reforming zone and the dehydrogenation zone and is fed to a second reforming zone. An effluent from the first reforming zone is fed to a plurality of reforming zones. The reforming catalyst moves downward through the multiple reforming zones then to a regenerator.

Abstract: An aromatics complex producing one or more xylene isomers offers a large number of opportunities to conserve energy by heat exchange within the complex. One previously unrecognized opportunity is through providing two parallel distillation columns operating at different pressures to separate C8 aromatics from C9+ aromatics. The parallel columns offer additional opportunities to conserve energy within the complex through heat exchange in associated xylene recovery facilities.

Abstract: The invention relates to removal of styrene from hydrocarbon mixtures, and more particularly, removal of styrene from hydrocarbon mixtures containing higher than equilibrium paraxylene concentrations.

Abstract: The invention is directed to purification of an aromatic hydrocarbon stream including selective removal of phenol from a process stream comprising aromatic hydrocarbon mixtures, especially aromatic hydrocarbon mixtures that contain higher-than-equilibrium paraxylene, by contact with suitable adsorbents, to provide a product stream having lower concentration of phenol than said process stream.

Abstract: The present invention is for a process for the alkylation of aromatic compounds, with a shape-selective zeolite catalyst. The process has reactors in series with C8+ aromatics being separated from the product stream effluents from each reactor before passing the reactor effluent to the next reactor with an additional input of methanol. The C8+ aromatics are separated into para-xylene and other C8+ aromatics. This process is applicable for toluene methylation having a molar excess of toluene:methanol. i.e., greater than 1:1, with a shape-selective catalyst of an aluminosilicate zeolite, such as ZSM-5 which has been modified with phosphorus, to produce para-xylene (p-xylene).

Abstract: A recovery method and a system for delivering extracted benzene, toluene, and xylene from a hydrocarbon gas stream is provided. The method includes introducing a feed stream of a BTX-rich hydrocarbon gas into an absorber. The method further includes combining, in the absorber, the hydrocarbon gas with an aprotic solvent, such that the hydrocarbon gas and the aprotic solvent are thoroughly intermixed so that the BTX is absorbed into the aprotic solvent, resulting in the production of a BTX-rich solvent and a substantially BTX-free gas. The method further includes vaporizing, using a vaporizer, the BTX-rich solvent to produce a vaporized BTX-rich solvent, and separating, using a distiller, the BTX from the vaporized BTX-rich solvent for delivering the extracted BTX from the hydrocarbon gas. The separation of the BTX from the vaporized BTX-rich solvent also produces a BTX-lean solvent that is recycled back into the absorber as the aprotic solvent.

Abstract: A process for maximizing p-xylene production includes producing a naphtha fraction and a light cycle oil fraction from a fluid catalytic cracking zone. These fractions are combined and hydrotreated. Fractionation of the hydrotreated product makes a hydrocracker feed that is sent to a hydrocracking zone to make a naphtha cut and a hydrocracker product. The hydrocracker product is recycled back to the fractionation zone, and the naphtha cut is dehydrogenated in a dehydrogenation zone to make aromatics. Reforming catalyst from a catalyst regenerator moves downward through the dehydrogenation zone. Straight run naphtha and raffinate from the aromatics unit are introduced to an additional series of reforming zones. The reforming catalyst moves in parallel through the first reforming zone and the dehydrogenation zones, then is combined for entry to the second and subsequent reforming zones prior to regeneration.

Abstract: A process for separating para-xylene from a plurality of xylene isomers, wherein the process introduces at a first feed point a first mixed xylene stream comprising a plurality of xylene isomers into a first adsorptive separation unit to produce a first para-xylene enriched stream and a first raffinate stream, and introduces a second mixed xylene stream comprising a plurality of xylene isomers into a second adsorptive separation unit to produce a second raffinate stream. The process feeds both the first raffinate stream and the second raffinate stream into a raffinate column. The process further introduces an extract stream from the second adsorptive separation unit into a first input of a split extract column comprising an internal partition defining a first distillation zone and a second distillation zone.

Abstract: A process for the purification of aromatic streams is provided that includes a new start up procedure that in embodiments significantly reduces impurities in an aromatics feedstock.

Abstract: The invention relates to regeneration of catalysts used in the purification of aromatics streams. It has been surprisingly found that retaining small amount of coke on the catalyst reduces regeneration costs and improves regeneration effectiveness.

Abstract: The apparatus includes at least two adsorptive separation zones to separate para-xylene from a feed stream comprising C8 aromatic hydrocarbons and at least one C9 aromatic hydrocarbon component. The first adsorptive separation zone delivers a raffinate stream to a raffinate distillation zone and an extract stream to an extract distillation zone. The raffinate distillation zone delivers a stream to the second adsorptive separation zone and at least one of the extract distillation zone and raffinate distillation zone delivers a recycle stream to the first adsorptive separation zone.

Abstract: Methods are disclosed for producing C8 aromatic hydrocarbons. Representative methods comprise fractionating a transalkylation effluent, exiting a transalkylation reaction zone and comprising C8 and C9 aromatic hydrocarbons, to provide a C8 aromatic hydrocarbon-enriched fraction and a C9 aromatic hydrocarbon-enriched fraction. The methods may further comprise (i) recycling the C9 aromatic hydrocarbon-enriched fraction to the transalkylation reaction zone and/or (ii) separating, in a xylene separation zone, isomers of C8 aromatic hydrocarbons in the C8 aromatic hydrocarbon-enriched fraction, into a para-xylene-enriched extract and a para-xylene-depleted raffinate. Performance in the transalkylation reaction zone is improved and/or downstream processing requirements in an aromatics complex are mitigated.

Abstract: In a process for reducing the amount of benzene produced in a startup procedure for purification of an aromatic feedstream, the improvement comprising a start-up procedure including contacting said catalyst with said feedstream at elevated LHSV for a period of time sufficient to reduce benzene and/or toluene levels to a predetermined level, and proceeding under normal operational conditions.

Abstract: A method for the solvent extraction of 1,3-butadiene from a mixture of C4 hydrocarbons that employs a distillation tower to produce the desired 1,3-butadiene product as an overhead and a separate bottoms stream that is removed from and not recycled in the solvent extraction process.

Abstract: The invention is an adsorptive separation process for producing a para-xylene product from a feed stream comprising para-xylene, at least one other C8 aromatic, and a C9 aromatic. An adsorbent comprising X or Y zeolite and a desorbent comprising para-diethylbenzene (p-DEB) are used in an adsorptive separation zone to produce an extract stream comprising para-xylene, p-DEB, and the C9 aromatic and a raffinate stream comprising the at least one other C8 aromatic, the C9 aromatic, and p-DEB. The extract stream is separated in an extract distillation zone to produce a second desorbent stream comprising the C9 aromatic and p-DEB and the raffinate stream is separated in a raffinate distillation zone to produce a third desorbent stream comprising the C9 aromatic and p-DEB. At least a portion of at least one of the second desorbent stream and the third desorbent stream is further separated in a desorbent distillation zone to produce a stream comprising the C9 aromatic.

Abstract: The present invention relates to a process for reducing the Bromine Index of a hydrocarbon feedstock having at least 50 wt. % of C8 aromatics, comprising the step of contacting the hydrocarbon feedstock with a catalyst at conversion conditions, wherein the catalyst includes a molecular sieve having a zeolite structure type of MWW.

Abstract: This disclosure relates to a process of manufacturing para-xylene, comprising (a) contacting a pygas feedstock and methylating agent with a catalyst under reaction conditions to produce a product having para-xylene, wherein the product has higher para-xylene content than the para-xylene content of the pygas feedstock; and (b) separating the para-xylene from the product of the step (a), wherein the catalyst comprises a molecular sieve having a Diffusion Parameter for 2,2-dimethylbutane of about 0.1-15 sec?1 when measured at a temperature of 120° C. and a 2,2-dimethylbutane pressure of 8 kPa-a and the pygas comprises from about 1 to about 65 wt % benzene and from about 5 to 35 wt % toluene.

Abstract: The apparatus includes at least two adsorptive separation zones to separate para-xylene from a feed stream comprising C8 aromatic hydrocarbons and at least one C9 aromatic hydrocarbon component. The first adsorptive separation zone delivers a raffinate stream to a raffinate distillation zone and an extract stream to an extract distillation zone. The raffinate distillation zone delivers a stream to the second adsorptive separation zone and at least one of the extract distillation zone and raffinate distillation zone delivers a recycle stream to the first adsorptive separation zone.

Abstract: Meta-xylene is recovered from admixture with other C8 aromatic hydrocarbons including ortho-xylene by liquid phase adsorptive separation. Performance is improved by reducing the concentration of ortho-xylene through adding a sidecut to a prefractionator preparing the feedstock to adsorptive separation.

Abstract: A method for the separation of hydrocarbon compounds utilizing a dividing wall distillation column is described. The dividing wall distillation column enables one or more side draw stream to be removed from the dividing wall distillation column in addition to an overhead stream and a bottoms stream.

Abstract: A catalytic process for the selective production of para-xylene comprises the step of reacting an aromatic hydrocarbon selected from the group consisting of toluene, benzene and mixtures thereof with a feed comprising carbon monoxide and hydrogen in the presence of a selectivated catalyst. The process includes a catalyst selectivation phase and a para-xylene production phase. In the catalyst selectivation phase, the aromatic hydrocarbon and the feed are contacted with the catalyst under a first set of conditions effective to increase the para-selectivity of said catalyst. In the para-xylene production phase, the aromatic hydrocarbon and said feed are contacted with the catalyst under a second set of conditions different from the first set of conditions effective to selectively produce para-xylene.

Abstract: Meta-xylene is recovered from admixture with other C8 aromatic hydrocarbons including ortho-xylene by liquid phase adsorptive separation. Performance is improved by reducing the concentration of ortho-xylene through adding a sidecut to a prefractionator preparing the feedstock to adsorptive separation.