Abstract: Method for the simulated moving bed (SMB) separation of a feedstock (F), in which: at least one zone (1, 2, 3, 4) contains fewer than three beds, if the stream (D, E, F, R) delimiting said zone and situated upstream of said zone is injected or withdrawn at the plate Pi via the bypass line Li/i+1, then the stream delimiting said zone and situated downstream of said zone is injected/withdrawn at the plate Pj via the bypass line Lj/j+1, and if the stream delimiting said zone and situated downstream of said zone is injected or withdrawn at the plate Pi via the bypass line Li?1/i, then the stream delimiting said zone and situated upstream of said zone is injected/withdrawn at the plate Pj via the bypass line Lj?1/j.

Abstract: The present disclosure provides a system and method for real time speciated or total measurement of chlorine containing compounds, specifically HCl and RCI, in combustion or process gas generated at refineries. The system may include a sample inlet line, a zero-filter, an RCI converter, an HCl analyzer, and an exhaust line. At least one valve may divert a sample gas to the components of the system. Plain lines and connectors connect the components of the system. The system may be installed as part of a continuous assembly or separate from an industrial operation unit in a facility. The method of measuring the chlorine concentration in the sample gas includes operating the system in a plurality of separate modes such that the sample gas is diverted to the different components of the system and analyzed accordingly.

Abstract: Method for the simulated moving bed separation of a feedstock (F), in which when a fluid/effluent (feedstock F, desorbent D, extract E, raffinate R) is injected/withdrawn into/from a chosen plate (Pi) using an external bypass line (Li?1/i, Li/i+1) connected to said chosen plate (Pi), the flow rate within the said external bypass line (Li?1/i, Li/i+1) is controlled in such a way that: a major proportion of the fluid/effluent (F, D, E, R) is injected/withdrawn into/from the chosen plate (Pi); and a minor proportion of the fluid/effluent (F, D, E, R) is injected/withdrawn into/from the adjacent plate (Pi?1, Pi+1) connected to the said external bypass line (Li?1/i, Li/i+1).

Abstract: A sorbent bed assembly of a fuel cell system, including a first sorbent bed, a second sorbent bed and at least one third sorbent bed, the second sorbent bed disposed between the first sorbent bed and the at least one third sorbent bed, a cover plate on the plurality of sorbent beds and configured to connect the sorbent beds to one another, a fuel inlet connector on the cover plate and configured to receive a fuel, a manifold having a first fluid conduit configured to transport fuel between the first sorbent bed and at least one third sorbent bed, and a second fluid conduit configured to transport fuel between at least one third sorbent bed and the second sorbent bed, and a fuel outlet connector on the cover plate and configured to receive fuel that has passed through each of the sorbent beds.

Abstract: A process for separating a product from a multicomponent feedstream to an adsorption apparatus or system is described. The apparatus or system may comprise a moving-bed or a simulated moving-bed adsorption means. The product comprises at least one organic compound, such as an aryl compound with alkyl substitutes. In embodiments the conduits used to supply the feedstream to the apparatus or system are flushed with media of multiple grades. The improvement is more efficient use of the desorbent. In embodiments the process achieves improvements in one or more of efficiency of adsorption separation, capacity of adsorption apparatus systems, and purity of product attainable by adsorption process.

Abstract: A process for purifying a hydrocarbon feed, using a first adsorption unit with first and second adsorption columns respectively filled with first and second adsorbent solids by simultaneously: a) treating the liquid phase hydrocarbon feed in the first adsorption column by contact with the first adsorbent solid to adsorb at least a portion of impurities present and to produce hydrocarbon effluent which is depleted in impurities; b) treating a secondary liquid hydrocarbon feed constituted either by a fraction of the hydrocarbon feed or by a fraction of the hydrocarbon effluent and depleted in impurities to purify the secondary liquid hydrocarbon feed; c) heating the treated secondary liquid hydrocarbon feed from step b); d) regenerating the second adsorbent solid of the second adsorption column which comprises impurities with the secondary hydrocarbon feed heated in step c) to desorb the impurities to produce an effluent with impurities.

Abstract: A process for separating para-xylene from a plurality of aromatic compounds, wherein the process introduces 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. The process further introduces a second mixed xylene stream comprising a plurality of xylene isomers into a second adsorptive separation unit to produce a second para-xylene enriched stream and a second raffinate stream. The process further feeds both the first raffinate stream and the second raffinate stream into a shared raffinate column.

Abstract: Rotary fluid processing systems and associated methods are disclosed. A purification system in accordance with the particular embodiment includes a rotatable adsorbent-containing heat/mass transfer element that is generally symmetric about a rotation axis, and includes multiple radial flow paths oriented transverse to the rotation axis and multiple axial flow paths oriented transverse to the radial flow paths. The axial flow paths and radial flow paths are in thermal communication with each other, and are generally isolated from fluid communication with each other at the heat transfer element. Particular embodiments can further include a housing arrangement having multiple manifolds with individual manifolds having an entry port and an exit port, and with individual manifolds having different circumferential locations relative to the rotation axis.

Abstract: Systems and methods for producing a hydrocarbon are provided. The method can include separating a hydrocarbon comprising olefins and paraffins to produce an olefin-rich hydrocarbon comprising about 70 wt % or more olefins and a paraffin-rich hydrocarbon comprising about 70 wt % or more paraffins. The method can also include cracking at least a portion of the olefin-rich hydrocarbon in the presence of one or more catalysts at conditions sufficient to produce a cracked product comprising about 20 wt % or more C2-C3 olefins.

Abstract: Embodiments of simulated moving bed systems for separating a preferentially adsorbed component from a feed stream and processes for determining a pump-around profile of the simulated moving bed systems are provided. The process comprises the steps of rotating a rotary valve to a first valve position to direct the feed stream to a first adsorbent sub-bed. An intermediate stream between two adsorbent sub-beds in direct fluid communication with each other is irradiated with laser light that is directed from a probe of a Raman system positioned for inline sampling of the intermediate stream. Scattered light from the irradiated intermediate stream is collected with the probe. A spectrum of the scattered light is generated with the Raman system to determine concentrations of the preferentially adsorbed component and one or more other components in the intermediate stream.

Abstract: A process for removing halogen compounds, particularly chlorine compounds, from a process fluid, includes the steps of (i) passing a process fluid containing hydrogen halide over a first sorbent to remove hydrogen halide and generate a hydrogen halide depleted process fluid and then, (ii) passing the hydrogen halide depleted process fluid over a second different sorbent to remove organic halide compounds therefrom. A purification system suitable for removing hydrogen halide and organic halide compounds from process fluids is also described.

Abstract: A process for separating a product from a multicomponent feedstream to an adsorption apparatus or system is described. The apparatus or system may comprise a moving-bed or a simulated moving-bed adsorption means. The product comprises at least one organic compound, such as an aryl compound with alkyl substitutes. In embodiments the conduits used to supply the feedstream to the apparatus or system are flushed with media of multiple grades. The improvement is a more efficient use of the desorbent. In embodiments the process achieves improvements in one or more of efficiency of adsorption separation, capacity of adsorption apparatus systems, and purity of product attainable by adsorption process.

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 removing heavy hydrocarbons from a natural gas stream comprises passing the natural gas stream thought a TSA adsorbent unit to adsorb heavy hydrocarbons, regenerating the TSA adsorbent by heating to form a contaminant-containing gas phase, cooling the contaminated gas phase to separate water and heavy hydrocarbon liquids to form a third gas phase and directing the third gas phase to a PSA unit to adsorb heavy hydrocarbons from the third gas phase. The product from the PSA unit can be sent to pipeline or recycled to the TSA unit for further hydrocarbon removal and recovery.

Abstract: A simulated moving bed separation process is characterized in that the feed and desorbant injection streams are each divided into N streams (N being a whole number strictly greater than 1) injected respectively at N distinct feed injection points and at N distinct desorbant injection points, and in that the extract and raffinate withdrawal points are also each divided into N streams each withdrawn from N distinct withdrawal points, the device being constituted by 4×N chromatographic zones.

Abstract: A process for desulphurizing hydrocarbons includes passing a mixture of hydrocarbon and hydrogen over a hydrodesulphurization catalyst to convert organosulphur compounds present in the hydrocarbon to hydrogen sulphide, passing the resulting mixture over a hydrogen sulphide sorbent including zinc oxide to reduce the hydrogen sulphide content of the mixture, and passing the hydrogen sulphide-depleted mixture over a further desulphurization material. The further desulphurization material includes one or more nickel compounds, a zinc oxide support material, and optionally one or more promoter metal compounds of iron, cobalt, copper and precious metals. The desulphurization material has a nickel content in the range 0.3 to 20% by weight and a promoter metal compound content in the range 0 to 10% by weight.

Abstract: A method of purifying 8-isoprostane is provided that includes a step of contacting a liquid sample containing 8-isoprostane with an ion exchange support having a quaternary ammonium salt immobilized thereon such that 8-isoprostane in the liquid sample is retained on the ion exchange support and a step of eluting 8-isoprostane from the ion exchange support using a first eluent containing a water-soluble organic solvent and water as main components.

Abstract: Processes and apparatuses are provided for preparing liquified natural gas from a natural gas feed that comprises C5 to C7 hydrocarbons and C8 or greater hydrocarbons. An exemplary process includes effecting the preferential adsorption of the C8 or greater hydrocarbons from the natural gas feed over adsorption of hydrocarbons having less than 8 carbon atoms to provide a C8-depleted natural gas stream. The process continues with effecting the preferential adsorption of the C5 to C7 hydrocarbons from the C8-depleted natural gas stream over adsorption of hydrocarbons having less than 5 carbon atoms to form a C5 to C8-depleted natural gas stream. The C5 to C7 hydrocarbons are preferentially adsorbed with higher selectivity and capacity than adsorption of the C5 to C7 hydrocarbons during preferentially adsorbing the C8 or greater hydrocarbons. The C5 to C8-depleted natural gas stream is then liquified.

Abstract: The invention concerns a device for distributing fluids which are to supply a multi-stage column having a succession of plates, each plate supporting a bed of granular solid (2) and being provided with a network for distributing said fluids constituted by substantially horizontal lines (6) having a plurality of degrees of branching from 1 to rank N, the ensemble of lines from rank P to rank N being adherent to the base plane of the plate under consideration, and the lines of the last degree of branching N communicating with mixing chambers (8) disposed immediately below said base plane.

Abstract: A process for separating a product from a multicomponent feedstream to an adsorption apparatus or system is described. The apparatus or system may comprise a moving-bed or a simulated moving-bed adsorption means. The product comprises at least one organic compound, such as an aryl compound with alkyl substitutes. In embodiments the conduits used to supply the feedstream to the apparatus or system are flushed with media of multiple grades. The improvement is a more efficient use of the desorbent. In embodiments the process achieves improvements in one or more of efficiency of adsorption separation, capacity of adsorption apparatus systems, and purity of product attainable by adsorption process.

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 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: Disclosed is a method for removing water, nitrogen compounds, and unsaturated aliphatic compounds from a hydrocarbon feed stream by passing the hydrocarbon feed stream through a water removal zone, a nitrogen removal zone, and an unsaturated aliphatic compound removal zone. By on aspect, the method includes removing water from the hydrocarbon feed stream, contacting the feed stream with a nitrogen selective adsorbent, and contacting the feed stream with an unsaturated aliphatic compound removal material.

Abstract: Disclosed is a method for treating two or more aromatic feed streams including combining one aromatic feed stream with another aromatic feed stream. The method further includes passing the combined feed stream to a unsaturated aliphatic compound removal zone for removing an unsaturated aliphatic compound therefrom. The method further includes passing the combined aromatic feed stream to a nitrogen removal zone for removing a nitrogen compound therefrom.

Abstract: A process to reduce flush circulation rates in an adsorption separation system is presented. The flush stream is used to improve the capacity of the simulated moving bed system by flushing the contents of the transfer lines containing raffinate material back into the adsorbent column. The flush stream is a material that is used to flush the head chambers in the column, or from the rotary valve flush dome sealant.

Abstract: The invention deals with a method for preparing a nitrogen-depleted hydrocarbon feedstock (315, 412, 514, 614, 714, 718, 814, 822) having (i) an initial boiling point comprised between 0° C. and +180° C. and a final boiling point comprised between 30° C. and 250° C., and (ii) an olefin content higher than 5 weight %, by contacting a hydrocarbon feedstock starting material (310, 313, 410, 411, 510, 512, 610, 612, 710, 712, 713, 810, 812, 813) with a clay sorbent material in a reaction vessel (33,43,53,63,73,73,83,83), wherein the nitrogen-depleted hydrocarbon feedstock (315, 412, 514, 614, 714, 718, 814, 822) has a total nitrogen/nitrile ratio (ppm/ppm) comprised between 1 and 5. Additional purification section allows improved units working time and lower maintenance.

Abstract: The present invention describes a process for pre-treating a steam reforming feed containing sulphur-containing compounds, using two desulphurization reactors: a temporary desulphurization reactor (1010) containing an active adsorbent solid; a permanent desulphurization reactor (1003) placed upstream of the steam reforming unit, which contains an adsorbent solid in the passivated state, necessitating a depassivation phase in order to be rendered active; the temporary desulphurization reactor (1010) being disconnected as soon as the adsorbent solid of the permanent desulphurization reactor (1003) has been activated, and the volume of the temporary desulphurization reactor being in the range 1/20 to 1/200 times the volume of the permanent desulphurization reactor.

Abstract: Disclosed is a method for removing unsaturated aliphatic compounds from a hydrocarbon feed stream by contacting the hydrocarbon feed stream with activated carbon to produce a hydrocarbon effluent stream having a lower unsaturated aliphatic content relative to the hydrocarbon feed stream. The hydrocarbon feed stream comprises an aromatic compound, a nitrogen compound, and an unsaturated aliphatic compound.

Abstract: Disclosed is a method for removing unsaturated aliphatic compounds from a hydrocarbon feed stream by contacting the hydrocarbon feed stream with an acidic molecular sieve to produce a hydrocarbon effluent stream having a lower unsaturated aliphatic content relative to the hydrocarbon feed stream. The hydrocarbon feed stream comprises an aromatic compound, a nitrogen compound, and an unsaturated aliphatic compound.

Abstract: Disclosed is a method for removing unsaturated aliphatic compounds from a hydrocarbon feed stream by contacting the hydrocarbon feed stream with an adsorbent comprising clay to produce a hydrocarbon effluent stream having a lower unsaturated aliphatic content relative to the hydrocarbon feed stream. The hydrocarbon feed stream comprises an aromatic compound, a nitrogen compound, and an unsaturated aliphatic compound.

Abstract: A process for separating para-xylene from a plurality of aromatic compounds, wherein the process introduces a mixed xylene feed stream comprising a plurality of xylene isomers into a first separation assembly to produce a first para-xylene enriched stream and a first raffinate stream. The process further feeds the raffinate stream into an isomerization unit to convert the raffinate stream into an isomerization reactor product stream, and introduces the isomerization reactor product stream into to a second para-xylene adsorptive separation unit to produce a second para-xylene enriched stream and a second raffinate stream.

Abstract: A process for separating para-xylene from a plurality of aromatic compounds, wherein the process introduces 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. The process further introduces a second mixed xylene stream comprising a plurality of xylene isomers into a second adsorptive separation unit to produce a second para-xylene enriched stream and a second raffinate stream. The process further feeds both the first raffinate stream and the second raffinate stream into a shared raffinate column.

Abstract: The present process comprises a means for energy savings in one or more process pumps by driving the one or more pumps with a variable-speed driving means. The invention is particularly useful in the separation of an adsorbed product from a mixture of components using simulated-moving-bed adsorption associated with a large circulating stream pumped with variable-speed driving means for conservation of energy relative to the known art. The improvement is particularly applicable to a process for the separation of para-xylene from mixed C8 aromatics.

Abstract: The present invention relates to a method for the separation of C4 olefins and C4 paraffins from a C4 hydrocarbon mixed gas including butene-1, trans-2- butene, cis-2-butene, normal butane, isobutane, etc. The method of the present invention produces C4 olefins with high purity by introducing a gaseous C4 mixture into the adsorption tower loaded with adsorbent selectively adsorbing olefins to adsorb C4 olefins and to discharge C4 paraffins to the outlet of the tower, desorbing C4 olefins adsorbed on the adsorption tower with a desorbent C5 hydrocarbon, C6 hydrocarbon, etc.), and then separating the C4 olefin and the desorbent by a distillation process.

Abstract: Embodiments of methods and apparatuses for treating a hydrocarbon-containing feed stream are provided. The method comprises the steps of contacting the hydrocarbon-containing feed stream comprising C4, C5, C6, and/or C7 hydrocarbons, water, and contaminants with a Linde Type A molecular sieve at dehydration conditions effective to remove water and form a dehydrated feed stream. The contaminants comprise oxygenates, sulfur compounds, or combinations thereof. The dehydrated feed stream is contacted with a sodium faujisite molecular sieve having a silica/alumina molar ratio of from about 2 to about 2.5 at absorption conditions effective to remove the contaminants and form a dehydrated contaminant-depleted feed stream.

Abstract: The present invention relates to a hybrid process comprising an adsorption process and a distillation process for the separation of butene-1 from a C4 hydrocarbon mixture gas including butene-1, trans-2-butene, cis-2-butene, normal butane, isobutane, etc. The above hybrid process comprises introducing a gaseous C4 mixture into the adsorption tower loaded with adsorbents which adsorb olefins selectively to discharge C4 paraffins to the outlet of the tower, desorbing C4 olefins selectively adsorbed in the adsorption tower to produce high purity C4 olefins mixture gas in which isobutane and normal butane was removed, and separating the high C4 olefins mixture gas (a mixture of butene-1, trans-2-butene, cis-2-butene, and a trace amount of C4 paraffins) via distillation to obtain high purity butene-1 including a trace amount of isobutane in the top of the distillation tower and obtain a mixture gas including trans-2-butene, cis-2-butene and a trace amount of normal butane in the bottom of the tower.

Abstract: Embodiments of the present invention provide, for an adsorption separation system for separating normal paraffins from a hydrocarbon feed stream, a process for switching the adsorption separation from a triple split desorbent system to a dual split desorbent system, and vice versa. Switching occurs by separating and/or introducing a second flush material in the adsorption separation system. This switching can occur during normal operations.

Abstract: A process to increase the capacity of the adsorbent in a normal paraffin adsorption separation system is presented. A tertiary flush stream is used to improve the capacity of the simulated moving bed system by flushing residual raffinate from the feed transfer line. The flushing removes residual raffinate containing desorbent that competes with the adsorption of normal paraffins from the feedstream. The flush stream is a material that will displace fluid in the column, but will not enter the pores of the adsorbent.

Abstract: A process is presented for the selective separation and recovery of large normal paraffins from a heavy kerosene boiling point fraction. The process includes passing the heavy kerosene fraction through an adsorption separation system for separating the normal paraffins from the paraffin mixture. The recovered extract and raffinate streams are mixed with a diluent made up of a lighter hydrocarbon. The subsequent diluted extract and raffinate streams are passed through first fractionation columns to separate the desorbent from the diluent and the heavier paraffins. The mixture of the diluent and heavier paraffins is passed through a second set of fractionation columns to separate the diluent and the heavier paraffins.

Abstract: A method of purifying 8-isoprostane is provided that includes a step of contacting a liquid sample containing 8-isoprostane with an ion exchange support having a quaternary ammonium salt immobilized thereon such that 8-isoprostane in the liquid sample is retained on the ion exchange support and a step of eluting 8-isoprostane from the ion exchange support using a first eluent containing a water-soluble organic solvent and water as main components.

Abstract: Disclosed is a method for removing unsaturated aliphatic compounds from a hydrocarbon feed stream by contacting the hydrocarbon feed stream with activated carbon to produce a hydrocarbon effluent stream having a lower unsaturated aliphatic content relative to the hydrocarbon feed stream. The hydrocarbon feed stream comprises an aromatic compound, a nitrogen compound, and an unsaturated aliphatic compound.

Abstract: A process to reduce flush circulation rates in an adsorption separation system is presented. The flush stream is used to improve the capacity of the simulated moving bed system by flushing the contents of the transfer lines containing raffinate material back into the adsorbent column. The flush stream is a material that is used to flush the head chambers in the column, or from the rotary valve flush dome sealant.

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 invention relates to processes for reducing the sulfur content in hydrocarbon fuels such as gasoline, diesel fuel and jet fuel. The invention provides a method and materials for producing ultra low sulfur content transportation fuels for motor vehicles as well as for applications such as fuel cells. The materials and method of the invention may be used at ambient or elevated temperatures and at ambient or elevated pressures without the need for hydrogen.

Abstract: To provide a method of purifying 2,7-dimethylnaphthalene comprising the step of bringing a raw oil containing a mixture of 1,7-dimethylnaphthalene and 2,7-dimethylnaphthalene together with a developing solvent into contact with L-type zeolite to thereby effect adsorption of 1,7-dimethylnaphthalene.

Abstract: A catalyst cooled is employed for converting oxygenates to light olefins. The catalyst becomes spent as deposits from the reaction clog up pores on the catalyst surface. A portion of the spent catalyst is regenerated in a regenerator and a portion is circulated back to contact more of the oxygenate feedstream. A catalyst cooler attached to the reactor can cool the spent catalyst circulated through the cooler before the spent catalyst contacts more of the oxygenate feedstream. In an embodiment, all of the spent catalyst that enters the catalyst cooler is withdrawn from the bottom of the catalyst cooler.

Abstract: A process is presented for the selective separation and recovery of large normal paraffins from a heavy kerosene boiling point fraction. The process includes passing the heavy kerosene fraction through an adsorption separation system for separating the normal paraffins from the paraffin mixture. The recovered extract and raffinate streams are mixed with a diluent made up of a lighter hydrocarbon. The subsequent diluted extract and raffinate streams are passed through first fractionation columns to separate the desorbent from the diluent and the heavier paraffins. The mixture of the diluent and heavier paraffins is passed through a second set of fractionation columns to separate the diluent and the heavier paraffins.

Abstract: An improved process for the production capacity and feedstock handling flexibility of a simulated moving bed adsorptive separation process by introducing a second feed stream to the adsorbent chamber comprising a feed material of a different concentration of the desired compound than the concentration of the desired compound in the first feed material stream. The introduction of this second feed material stream may be performed at any location on the adsorbent chamber between (i) a transfer point located immediately upstream of the point of the raffinate material stream withdrawal from the adsorbent chamber to (ii) a transfer point located immediately downstream of the point of extract material stream withdrawal from the adsorbent chamber. A recycle stream may be introduced into the system at a location having a concentration similar to the concentration of the first feed material stream.

Abstract: A process for separating a feed F by simulated moving bed adsorption in a SMB device comprises at least one zone 1 for desorption of the compounds produced in the extract, a zone 2 for desorption of the compounds produced in the raffinate, a zone 3 for adsorption of the compounds produced in the extract, a zone 4 located between the raffinate withdrawal and the desorbant supply, the device comprising external by-pass lines Li/i+1 directly connecting two successive plates Pi and Pi+1; in which the degree of opening of means for restricting the flushing flow rate of the by-pass lines Li/i+1 are sequentially modified such that: 1) in an operational zone where there is at least one closed by-pass line, a super-synchronicity of the flushing flow rate is established in all of the by-pass lines which are not closed belonging to the zone under consideration, said super-synchronicity being defined by the following formula: S=a+b(nf/nt) in which the constant a is a constant in the range ?5 to 5 and b is a constan

Abstract: An exemplary embodiment can be a process for removing one or more polynuclear aromatics from at least one reformate stream from a reforming zone. The PNAs may be removed using an adsorption zone. The adsorption zone can include first and second vessels each vessel containing an activated carbon adsorbent. Generally, the process includes passing the at least a portion of an effluent of the reforming zone through the first vessel containing a first activated carbon adsorbent wherein the first activated carbon adsorbent comprises iron.