Abstract: For producing three effluents which are respectively rich in straight chain paraffins, in mono-branched paraffins, and in di-branched and tri-branched paraffins possibly with naphthenic and/or aromatic compounds, from C5-C8 cuts or intermediate cuts (C5-C7, C6-C8, C7-C8, C6-C7, C7 or C8), comprising paraffic and possibly naphthenic, aromatic and olefinic hydrocarbons, the separation process of the invention uses at least two separation units operating either by adsorption or by permeation. It is of particular application when coupled with a hydro-isomerization process, which selectively recycles straight chain and mono-branched paraffins, necessary with paraffins containing more than 7 carbon atoms.

Abstract: A process for separating meta-xylene from a mixture containing meta-xylene, para-xylene, and ortho-xylene has been developed. The process involves contacting the mixture with zeolite Beta to effect the adsorption of the para-xylene, ortho-xylene, and ethylbenzene in preference to the meta-xylene and recovering the meta-xylene.

Abstract: A molecular sieve guard bed used in an adsorptive process for separating olefinic hydrocarbons from paraffinic hydrocarbons is regenerated in a method which recovers valuable hydrocarbons from the guard bed void volumes. The method comprises first contacting the sieve with a purge stream, with the initial effluent of the guard bed passed into a raffinate column to recover the olefinic hydrocarbons in the void volume of the bed. The flow of the effluent of the guard bed is then switched to a different fractionation column.

Abstract: A process for separating para-xylene from a C.sub.8 feed in a simulated moving bed comprises a step for adsorption on a zeolite and desorption using a desorbent delivering an extract and a raffinate, and an extract crystallization step. A stream of water is introduced into the feed, into the desorbent and/or into the stream for recycling one flux in the column, such that the weighted average of the amounts of water measured in the extract and in the raffinate is in the range 1 to 200 ppm. The ratio S/F of the desorbent flow rate to that of the feed during the adsorption and desorption step is in the range 0.6 to 2.5.

Abstract: Removal of aromatic sulfur compounds from an FCC feedstock with minimal adsorption of aromatic hydrocarbons is achieved using a zeolite Y exchanged with alkali or alkaline earth cations. KY is an especially effective adsorbent. Where the KY is impregnated with a group VIII metal, particular palladium or platinum, the adsorbent is effectively regenerated by treatment with hydrogen at elevated temperatures.

Abstract: A process is provided for reducing the sulfur content of a hydrocarbon stream, wherein a hydrocarbon stream containing sulfur constituents is contacted with a sorbent under temperature and pressure conditions of low severity. The sorbent includes a metal-exchanged zeolite selected from a group consisting of Y zeolites, ultra-stable Y zeolites, and mixtures thereof. A preferred sorbent is a fluid catalytic cracking (FCC) catalyst having a rare earth metal exchanged Y zeolite or ultra-stable Y zeolite. The sorbent adsorbs sulfur constituents contained in the hydrocarbon stream upon contact therewith to reduce the sulfur content of the hydrocarbon stream.

Abstract: Applicant has discovered a new zeolite containing composition and a process for preparing the same. The composition is unique in that the zeolite crystals making up one layer of the composition pack in a manner such that the composition is essentially continuous with no large scale voids even when the zeolite layer is <10 .mu.m thick. Thus, the present invention is directed toward a composition comprised of a porous substrate and a layer of zeolite crystals wherein said layer of zeolite crystals is a polycrystalline layer with at least 99% of said zeolite crystals having at least one point between adjacent crystals that is .ltoreq.20 .ANG. and wherein at least 90% of said crystals have widths of from about 0.2 to about 100 microns (preferably about 2 to about 50 microns) and wherein at least 75% of said crystals have a thickness of within 20% of the average crystal thickness. Preferably the composition has at most 1 Volume % voids in the zeolite layer. Use of the composition is also described.

Abstract: Hydrocarbon fluid catalytic cracking (FCC) plants are debottlenecked by subjecting part or all of the wet gas stream leaving the main fractionator overhead receiver to pressure swing adsorption to remove methane and hydrogen from this gas stream prior to its introduction into the wet gas compressor. This allows debottlenecking of the compressor system. It can allow the reduction in pressure in the system back to the catalyst regenerator. The reduction in pressure in the catalyst regenerator makes it possible to increase the rate of regeneration of catalyst. Consequently, the rate of hydrocarbon throughput in the FCC plant can be increased.

Abstract: A process for removing sulfur containing compounds from various hydrocarbon streams is disclosed and claimed. The process involves contacting the feedstream with an adsorbent such as nickel exchanged zeolite X or Y, or a smectite layered clay having a surface area of at least 150 m.sup.2 /g, thereby adsorbing the sulfur compounds onto the adsorbent.

Abstract: A hydrocarbon stream is cracked to produce a hot gaseous stream which is compressed and cooled to condense almost all of the hydrocarbons contained in the stream. A noncondensed stream remaining after the condensation step, comprised predominantly of hydrogen and C.sub.1 to C.sub.3 hydrocarbons, is subjected to pressure swing adsorption or temperature swing adsorption at an adsorption temperature of about 0.degree. to about 250.degree. C. in a bed of adsorbent which selectively adsorbs ethylene and propylene, thereby adsorbing substantially all of the ethylene and propylene from the gas stream. The ethylene and/or propylene is recovered upon bed regeneration.

Abstract: Paraffin cuts contaminated with aromatic compounds are brought in contact at ambient temperature with faujasites, in which the Si/Al ratio is less than 1.2, in particular, sodium faujasites which were partially exchanged with lithium. Thus, one can obtain purified cuts which are practically totally free from aromatic contaminants.

Abstract: There is provided a hydrocarbon conversion process and a process for sorbing a sorbate wherein said conversion and sorption process each comprises the use of a porous material. A process for preparing this material involves adding an amphiphilic compound to the reaction mixture for preparing a crystalline oxide. The amphiphilic compound may be a quaternary ammonium cationic surfactant. These surfactants may be in the form of lamellar liquid crystals, and may function as templates for the formation of the present mesoporous oxide materials.

Abstract: A process for separating at least one component from a mixture of components which comprises contacting the mixture with a sorbent structure comprising a film of interconnected zeolite crystals bonded to a substrate, said sorbent structure being characterized by a value r representing the mg of zeolite/cm.sup.2 of substrate surface and a value e representing the coating efficiency as mg of bonded zeolite/mg of YO.sub.2 initially in the synthesis mixture, wherein r is at least 0.5 and e is at least 0.05.

Abstract: A totally contained adsorption process for the substantial total removal and conversion of benzene to cyclohexane in gasoline boiling range streams. At least a portion of the gasoline boiling range stream is passed through an adsorption zone containing an adsorbent which will selectively adsorb benzene from the stream. The process is totally contained in the sense that substantially total conversion of benzene to cyclohexane is achieved without the need for added desorbent. The desorbent is cyclohexane which is generated in the process.

Abstract: A process for purifying linear paraffins in which a hydrocarbon stream containing linear paraffins contaminated with aromatics, sulfur-, nitrogen-, and oxygen-containing compounds, and color bodies, but essentially free of olefins, is contacted with a zeolitic solid adsorbent such as a NaX zeolite or zeolite MgY. After adsorption the zeolitic solid adsorbent is desorbed with an alkyl-substituted aromatic desorbent such as toluene.

Abstract: A method for the separation of benzene from a hydrocarbon stream, such as a gasoline boiling range stream, which comprises contacting the hydrocarbon stream with an adsorbent capable of selectively adsorbing the benzene from the stream, hydrogenating the adsorbed benzene to cyclohexane, and desorbing the cyclohexane from the adsorbent. The hydrogenation of the benzene to cyclohexane facilitates the removal of the benzene from the adsorbent.

Abstract: A method for selectively separating benzene from gasoline boiling range streams by first fractionating the stream to produce a C.sub.6 heartcut fraction which is then passed to an adsorption zone comprised of a bed of solid adsorbent material capable of selectively removing benzene from the stream. The absorbent is regenerated with a suitable desorbent, preferably toluene.

Abstract: A process for separation and removal of stable polycyclic aromatic dimer foulants from refinery process streams by selectively adsorbing the foulants while eluting non-fouling smaller-ringed aromatics. Synchronous Scanning Fluorescence may be used in the identification and monitoring of the stable polycyclic aromatic dimers.

Abstract: A method for selectively separating benzene from gasoline boiling range streams by first passing the stream to an adsorption zone comprised of an adsorbent capable of selectively adsorbing benzene from the stream. A substantially benzene-free stream results and the adsorbent is regenerated by treating it with a desorbent solvent capable of desorbing benzene from the solid adsorbent.

Abstract: A process for purifying linear paraffins in which a hydrocarbon feedstream containing linear paraffins contaminated with aromatics, sulfur-, nitrogen-, and oxygen-containing compounds, and color bodies, and also containing up to about 5 wt % desorbent from effluent recycle, is contacted with a solid adsorbent such as a NaX zeolite or zeolite MgY; after adsorption the adsorbent is desorbed with an alkyl-substituted aromatic desorbent, such as toluene. As the adsorent bed is being desorbed, the initial effluent from the adsorption cycle will contain levels of desorbent and may be recycled to the hydrocarbon feedstream. Previous to the removal of impurities from the adsorbent by desorption, the desorbent displaces interstitial linear paraffins which are also recycled to the hydrocarbon feedstream.

Abstract: A hydrocarbon containing sulfides, disulfides, trisulfides, tetrasulfides or mixtures can be desulfurized by contacting the hydrocarbon with a zeolite containing copper, silver, zinc or mixtures thereof.

Abstract: An improved adsorption-desorption process is disclosed for separating low octane components from field natural gasoline and virgin naphthas. The low octane materials may be further separated into chemical feed stocks, fluid catalytic cracking feed stocks, steam active reforming feed stocks, paraffinic solvents, and diesel and jet fuel blend stocks by conventional fractionation and/or solvent extraction processes. The remaining higher octane materials make excellent reformer feed and/or gasoline blend stocks.

Abstract: A process for the separation of 2,4 DCP from a hydrocarbon feed mixture comprising 2,4 and 2,6 DCP which process employs an adsorbent comprising a type X or type L zeolite which has been cation exchanged at appropriate conditions with one or more cations selected from the group consisting of alkaline metals, alkaline earths and Group VIII elements of the Periodic Table. The adsorbed DCP isomer(s) thereafter is removed from the adsorbent by contacting it with a desorbent material and is recovered to an extract product stream, likewise the remainder of the feed material is recovered to a raffinate product stream. In a preferred embodiment the process uses a simulated moving-bed countercurrent flow system.

Abstract: The present invention relates to a new and integrated process involving the utilization of a primary adsorption bed containing a regenerable, physical adsorbent and an auxiliary sorption bed containing a chemisorbent for the removal of sulfur compounds from a fluid stream, which process provides for higher yields, higher purity and lower costs. A system for removing sulfur compounds in accordance with the above process is also disclosed.

Abstract: A process for treating catalytic particles in a vertical chamber is disclosed. The catalytic particles comprise spent catalysts from such hydroprocesses as hydrocracking and hydroreforming. The process comprises suspending the catalytic particles in a gaseous atmosphere of a vertical chamber for a time sufficient to remove the waste products from the catalytic particles. The process can be used to remove carbonaceous and sulfur deposits from the surface of the particles as well as volatile hydrocarbons and hydrates.

Abstract: A process for purifying linear paraffins in which a hydrocarbon stream containing linear paraffins contaminated with aromatics, sulfur-, nitrogen-, and oxygen-containing compounds, and color bodies, but essentially free of olefins, is contacted with a solid absorbent such as a NaX zeolite or zeolite MgY. After adsorption the adsorbent is desorbed with an alkyl- substituted aromatic desorbent, such as tuluene. The initial effluent from the adsorb cycle, which will contain a high concentration of residual desorbent, is recycled to a desorbent recovery system. The level of desorbent in the adsorber effluent is monitored on a real time basis until the desorbent level of the adsorber effluent declines from a plateau level, i.e., a 100% plateau level, that correlates with the level of impurities, particularly the aromatic impurities in the feed, which is an indication of aromatics breakthrough, thereby signaling the need to switch the adsorbent beds.

Abstract: A chromatographic process able to separate paraxylene from C.sub.8 isomers and C.sub.9 aromatics. In the process, the para-xylene-containing feed mixture is contacted with an X or Y zeolite adsorbent having Group IA or IIA cations, e.g., barium and/or potassium, at exchangeable cationic sites while maintaining the water content of the adsorbent at about 4.2-6% (LOI). The para-xylene components are selectively adsorbed onto the adsorbent. The non-adsorbed feed is then removed from the adsorbent and the para-xylene recovered by desorption with tetralin or alkyl derivatives of tetralin. The C.sub.9 's and the other xylene isomers in the raffinate, can be separated from this heavy desorbent by fractionation of the raffinate and the desorbent recycled to the process.

Abstract: According to the invention, the oil is passed through a pulverulent material, such as an earth or clay, in the presence of an acid. The pulverulent material can be placed beforehand on a filter or can be mixed with the oil before filtration. If necessary, the oil is recycled through the filter up to complete decontamination.Application to the radioactive decontamination of oils used in the nuclear industry.

Abstract: A chromatographic process able to separate para-xylene frpm C.sub.8 isomers and C.sub.9 aromatics. In the process, the para-xylene-containing feed mixture is contacted with an X or Y zeolite adsorbent having Group IA or IIA cations, e.g., barium and/or potassium, at exchangeable cationic sites. The para-xylene components are selectively adsorbed onto the adsorbent. The non-adsorbed feed is then removed from the adsorbent and the para-xylene recovered by desorption with tetralin or alkyl derivatives of tetralin. The C.sub.9 's and the other xylene isomers in the raffinate, can be separated from this heavy desorbent by fractionation of the raffinate and the desorbent recycled to the process.

Abstract: A hydrotreating process uses a separation section that reduces the loss of C.sub.4 and higher hydrocarbons through the use of a low hydrogen to hydrocarbon ratio in the reactor and the adsorptive removal of a majority of hydrogen sulfide from a liquid phase hydrotreater effluent. Sulfurous hydrocarbon feed is admixed with hydrogen to maintain a hydrogen to hydrocarbon ratio of less than 50 SCFB. The hydrogen and hydrocarbons are passed through a hydrotreater reactor to convert sulfur compounds to H.sub.2 S. The hydrotreater effluent is cooled and after flashing of any excess hydrogen or light ends the cooled effluent is contacted with an adsorbent material for the removal of H.sub.2 S. A hydrotreated hydrocarbon product is withdrawn from the adsorption section. The low hydrogen to hydrocarbon ratio permits the process to be used without the recycle of hydrogen thereby eliminating the need for separators and compressors that were formly used to recycle hydrogen to the hydrotreater.

Abstract: Methods are provided for regenerating a zeolitic molecular sieve having a sulfur-containing carbonaceous material deposited thereon by contacting the zeolitic molecular sieve with an oxygen-containing regeneration feed gas to remove at least a portion of the carbonaceous deposit material and thereafter absorbing sulfur oxides present in the regeneration gas using soda-lime absorbent. The methods can inhibit the deactivation of zeolitic molecular sieves by avoiding contact thereof with the sulfur oxides. In a specific aspect of the present invention, the regeneration method is incorporated into a method for separating normal paraffins from a sulfur-containing hydrocarbon feed in the gas oil or kerosene carbon range.

Abstract: The present invention is a concentration swing adsorption process for separating a liquid phase feedstock comprising a more adsorbable component (A) and a less adsorbable component (B) with respect to an adsorbent. The process is operated in a system comprising a single or a plurality of adsorption columns containing the adsorbent which are operated in cycle in a predetermined sequence. The following operational steps are performed in the order recited in each of the adsorption columns in its turn. Feedstock is passed through the adsorbent and the more adsorbable component (A) is selectively adsorbed while a stream enriched in component (B) is discharged from the adsorption column. The adsorbent is rinsed in a direction co-current to the feedstock with the more adsorbable component (A) whereby the less adsorbable component (B) is displaced from the adsorbent and a stream comprising a mixture of the more adsorbable component (A) and the less adsorbable component (B) is withdrawn from the adsorption column.

Abstract: This invention comprises a process for separating 3,5-diethyltoluene from a feed mixture comprising 3,5-diethyltoluene and at least one isomer thereof, which process comprises contacting the mixture at adsorption conditions with an adsorbent comprising an X zeolite cation exchange with a K cation, thereby selectively adsorbing the 3,5-diethyltoluene. The remainder of the feed mixture is removed by desorption at desorption conditions with a desorbent material comprising a monocyclic alkyl-substituted aromatic hydrocation, e.g., p- or m-diethylbenzene or p-cymene and optionally, a diluent, e.g., isooctane.

Abstract: A process for enriching the fraction of 2,6-diisopropylnaphthalene contained in a quantity of mixed dialkylated naphthalenes. The mixed dialkylated naphthalenes are contacted with an adsorbant bed containing one or more molecular sieves which demonstrate shape selective preference for the 2,6-diisopropylnaphthalene isomer over other dialkylated naphthalenes. The adsorbant bed is then contacted with a desorbant capable of desorbing the 2,6-diisopropylnaphthalene from the pores of the adsorbant.

Abstract: A chromatographic process able to separate para-xylene from C.sub.8 isomers and C.sub.9 aromatics. In the process, the para-xylene-containing feed mixture is contacted with an X or Y zeolite adsorbent having Group IA or IIA cations, e.g., barium and/or potassium at exchangeable cationic sites. The para-xylene is selectively adsorbed onto the adsorbent. The feed is then removed from the adsorbent and the para-xylene recovered by desorption with diethyltoluene. The C.sub.9 's and the other xylene isomers in the raffinate, can be separated from this heavy desorbent by fractionation of the raffinate and the desorbent recycled to the process. The preferred desorbents are 2,3-diethyltoluene, 2,5-diethyltoluene and 2,6-diethyltoluene.

Abstract: Processes are disclosed for the separation of light hydrocarbons from a feedstream containing hydrogen, light hydrocarbons and heavy hydrocarbons. The processes employ thermal swing adsorption zone to adsorb heavy hydrocarbons and a pressure swing adsorption zone to remove the remaining light hydrocarbons. At least a portion of the product from the pressure swing adsorption zone is used to purge the thermal swing adsorption zone. Specific applications of the process of the present invention are disclosed with relation to hydrodealkylation processes and dehydrocyclodimerization processes.

Abstract: A continuous process is presented for the production and recovery of a high purity stream of 2,6-dimethylnaphthalene. The process comprises the general steps of: fractionating a hydrocarbon feed stream to recover a process stream rich in the various isomers of dimethylnaphthalene; subjecting the process stream rich in isomers of dimethylnaphthalene to a selective adsorption step to produce at least two streams of dimethylnaphthalene isomers, one lean in the 2,6-dimethylnaphthalene isomer and subjecting the stream of dimethylnaphthalene isomers lean in the 2,6 isomer to isomerization to increase the concentration of the 2,6 isomer of dimethylnaphthalene therein and directing the isomerized stream back to the fractionation zone to further processing.

Abstract: A process of separating the ortho, meta and para isomers of ethyltoluene. One aspect employs a ferrierite absorbent which separates the para isomer from a mixture of the same and at least one of the meta and ortho isomers. A second aspect employs a silicalite absorbent which separates the ortho isomer from a mixture of the same and the meta isomer. A third aspect combines the ferrierite and silicalite absorbents in sequence to separate a mixture of the ortho, meta and para isomers into the essentially pure compounds.

Abstract: A method of separating 2,6-diisopropylnaphthalene from a mixture containing 2,6-diisopropylnaphthalene and structural isomers thereof including the 2,7-isomer is disclosed, wherein the mixture is first subjected to a selective adsorption and desorption treatment using a zeolite absorbent capable of adsorbing the 2,7-isomer to obtain a first extract containing the sorbed 2,7-isomer and a first raffinate containing non-sorbed isomers including the 2,6-isomer, the 2,6-isomer being thereafter separated from the first raffinate.

Abstract: The chromatographic adsorption separation of coumarone from indene-containing coal tar distillate feed mixtures with an alkali metal (Group IA) exchanged X-zeolite and polar materials, e.g., ketones, alcohols or esters as desorbents. Also disclosed is a process for separating a coumarone-indene coextract with sodium-exchanged Y zeolite and toluene as desorbent.

Abstract: The invention relates to a method of operating an adsorption system using only two adsorption beds, for control of output quality of a gas containing a hydrocarbon. In the method before complete changeover of one bed A from adsorption to regeneration and of the other bed B from adsorption to regeneration, the adsorption feed gas flow is split into two streams of equal flow rate in the embodiment described, flowing in parallel through the beds and recombining the gas from the adsorbing bed A and the regenerating bed.

Abstract: The invention is a process for separating a mixture of saturated hydrocarbons into normal paraffins, branched chain paraffins, and cyclic paraffins which comprises contacting said mixture with a series of two molecular sieves comprising a first silicalite and a second silicalite which have different retention conditions. One of the silicalites is selected so that it will retain normal paraffins and pass through branched chain paraffins and cyclic paraffins. The second silicalite is selected so that it will retain normal and branched chain paraffins and pass through cyclic paraffins. The two molecular sieves are employed in series so that the mixture of saturated hydrocarbons can be separated into normal paraffins, branched chain paraffins, and cyclic paraffins.

Abstract: A hydrotreating process uses a separation section that reduces the loss of C.sub.5 and higher hydrocarbons through the use of a low hydrogen to hydrocarbon ratio in the reactor and the adsorptive removal of a majority of hydrogen sulfide from a liquid phase hydrotreater effluent. Sulfurous hydrocarbon feed is admixed with hydrogen to maintain a hydrogen to hydrocarbon ratio of less than 50 SCFB. The hydrogen and hydrocarbons are passed through a hydrotreater reactor to convert sulfur compounds to H.sub.2 S. The hydrotreater effluent is cooled and after flashing of any excess hydrogen or light ends the cooled effluent is contacted with an adsorbent material for the removal of H.sub.2 S. A hydrotreated hydrocarbon product is withdrawn from the adsorption section. The low hydrogen to hydrocarbon ratio permits the process to be used without the recycle of hydrogen thereby eliminating the need for separators and compressors that were formerly used to recycle hydrogen to the hydrotreater.

Abstract: A catalytic hydrocracking process which comprises: (a) contacting a hydrocarbonaceous feedstock having a propensity to form 11.sup.+ ring heavy polynuclear aromatic compounds and a liquid recycle stream in a hydrocracking zone with added hydrogen and a metal promoted hydrocracking catalyst at elevated temperature and pressure sufficient to convert a substantial portion of the feedstock to lower boiling hydrocarbon products; (b) partially condensing the hydrocarbon effluent from the hydrocracking zone to produce a gaseous hydrocarbon stream comprising hydrogen, and an unconverted hydrocarbon stream having components boiling above about 400.degree. F. (204.degree. C.) and comprising trace quantities of 11.sup.

Abstract: Dewaxed oils can have their low temperature performance improved by the removal of residual wax by adsorption of said residual wax onto a hydrophobic molecular sieve. The wax-laden hydrophobic molecular sieve is regenerated by use of dewaxing solvents, such as ketones.The dewaxed oils, which have residual wax removed by the present invention, are oils which have been dewaxed by means of solvent dewaxing procedures or by catalytic dewaxing processes. These oils, produced by the combination of conventional-adsorptive trim dewaxing, exhibit superior formulated oils low temperature performance as compared to formulated oils made from oils dewaxed to the same pour point solely by conventional dewaxing by either solvent or catalytic processes practiced under severe conditions (deep dewaxing).

Abstract: A process for separating 3,5-diethyltoluene (3,5-DET) and/or 2,6-diethyltoluene (2,6-DET) from a feed mixture comprising at least one isomer from the group 3,5- and 2,6-diethyltoluene and at least one other isomer thereof, which process comprises contacting the mixture at adsorption conditions with an adsorbent comprising an X zeolite, cation exchanged with a mixture of barium and potassium or sodium, lithium, barium or copper cations or mixtures thereof or a Y zeolite cation exchanged with barium, calcium, sodium, potassium or copper cations or mixtures thereof, thereby selectively adsorbing one or more of said isomers and removing one or more relatively non-adsorbed isomer(s) from contact with the adsorbent. 2,6-diethyltoluene is the most strongly adsorbed isomer with certain adsorbents and is recovered by desorption at desorption conditions with a desorbent material comprising a monocyclic alkyl-substituted aromatic hydrocarbon, e.g.

Abstract: A process for the separation of the para-isomer from a hydrocarbon feed mixture comprising at least two bi-alkyl substituted monocyclic aromatic isomers, including the para-isomer, said isomers having from 8 to about 18 carbon atoms per molecule which process employs an adsorbent comprising a sodium Y zeolite or a sodium Y zeolite which has been at least partially cation exchanged, at appropriate conditions, with an element chosen from Groups IB or VIII of the Periodic Table, such as nickel or copper, to preferentially adsorb the bi-alkyl substituted monocyclic aromatic isomers, in preference to the para-isomer. The para-isomer thereafter is removed from the process via the raffinate stream and the adsorbed isomers are removed from the adsorbent by contact with a desorbent material and are recovered as a product stream. In a preferred embodiment the process uses a simulated moving-bed countercurrent flow system and a paradiethylbenzene desorbent.

Abstract: Molecular sieves are used to remove sulfur compounds (e.g., COS and H.sub.2 S) from liquid hydrocarbon streams, particularly liquid propane. During regeneration of the sieves, some of the liquid hydrocarbons remains on the sieves and is lost by vaporization during the purge step and the liquid fill step. This invention reduces the loss by recovery and recycle of the vaporized hydrocarbons in the liquid recovery process.

Abstract: A process for the separation of 2,7 DIPN from a hydrocarbon feed mixture comprising 2,7 DIPN and one or more other DIPN isomers, which process employs an adsorbent, comprising a type Y zeolite, dried to an LOI less than 10% which has been at least partially cation exchanged, at exchangeable sites, with potassium. The 2,7 DIPN thereafter is removed from the adsorbent by contacting it with a desorbent material, comprising toluene, at desorbent conditions, and is recovered as an extract product stream. In a preferred embodiment, the process uses a simulated moving-bed countercurrent flow system.

Abstract: Processing and apparatus are provided for upgrading the octane of a mixed hydrocarbon gasoline feedstock by an integrated adsorption-isomerization process which catalytically isomerizes normal paraffinic hydrocarbons and concentrates non-normals in a product stream, in both the reactor-lead and adsorber-lead configuration.The process includes passing an adsorber feed stream comprising hydrogen as well as hydrocarbons to an adsorbent bed to adsorb normal hydrocarbons. The hydrogen is preferably obtained from a hot hydrogen-containing process stream which is not cooled or separated into component parts prior to forming the adsorber feed. In some embodiments, the hot-hydrogen containing stream comes from reactor effluent and in others from desorption effluent.According to the invention, the only hydrogen which will require cooling and separation from a hydrocarbon component is that which is recycled for desorption. The invention provides improved energy efficiency and can reduce equipment size and complexity.