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 constant

Abstract: Process for separation of a feedstock F by adsorption in a simulated moving bed in an SMB device that comprises a zone 1 for desorption of compounds produced by extraction, a zone 2 for desorption of compounds produced with a raffinate, a zone 3 for adsorption of compounds produced by extraction, and a zone 4 that is located between the draw-off of the raffinate and the supply of the desorbent, whereby the device comprises external bypass lines Li/i+1 directly joining two successive plates Pi, Pi+, that are equipped with non-automated means for adjusting flow rate and closing means, in which the degree of opening of the restriction means of the scavenging flow rate of the bypass lines Li/i+1 is adjusted so as to obtain the best performance of the SMB.

Abstract: The present invention describes a method for measuring the concentrations of species present at one point of a separation unit functioning in simulated moving bed mode (SMB), using an immersing probe located at one point in the unit or on one of the streams entering or leaving said unit, and a thermocouple located in the vicinity of the immersing probe, in which a Raman spectrum obtained using a laser source functioning at a wavelength of 785 nm is utilized. Application of the method to controlling and regulating a SMB xylenes separation unit.

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: The invention relates to aggregate zeolitic adsorbents based on faujasite X type zeolite powder having a low silica content and small crystals, exchanged with barium or based on faujasite X type zeolite having a low silica content and small crystals, exchanged with barium and potassium. The invention also relates to the method for preparing said aggregate zeolitic adsorbents, and also their uses for separating sugars, polyhydric alcohols, isomers of substituted toluene, cresols, or for recovering very high purity paraxylene.

Abstract: A device (SMB) for separation by simulated moving bed adsorption comprises a plurality of elementary zones Zi in series operating in a closed loop, each of said zones comprising, between two successive fluid injection or extraction points, a unique bed Li of adsorbant solid with volume VAi and a non-selective free volume Vi, in which the majority of the zones are ordinary elementary zones each having an identical volume VA of the same adsorbant S, and a substantially identical non-selective free volume equal to V; the device also comprises at least one particular elementary zone Z0, termed the particular elementary zone, comprising a non-selective free volume V0 which is greater than V, and a unique bed L0 of adsorbant S0 with volume VA0 which is less than VA, S0 having a volume adsorption capacity C0 which is greater than that, C, of S, such that the overall adsorption capacity C0×VA0 of Z0 is closer to the overall adsorption capacity C×VA of each of the ordinary elementary zones than the overall adsorption

Abstract: The present invention relates to aggregate zeolitic adsorbents based on zeolite X and zeolite LSX. These adsorbents are particularly suitable for separating C8 aromatic isomers and in particular xylenes, separating sugars, separating polyhydric alcohols, separating isomers of substituted toluenes, separating cresols, separating dichlorobenzenes.

Abstract: A device (SMB) for separation by simulated moving bed adsorption comprises a plurality of elementary adsorption zones Zi in series operating in a closed loop, and at least one singular adsorption zone with a dead volume which is greater than the adsorption zones Zi, the solid adsorbant of said singular adsorption zone having a granulometry which is lower than that of the solid adsorbant of the ordinary adsorption zones.

Abstract: The invention concerns a process for producing high purity meta-xylene, comprising a step for separation by simulated moving bed adsorption starting from an aromatic C8 feed delivering a fraction which is rich in meta-xylene and a fraction which is depleted in meta-xylene, and a step for crystallization of the meta-xylene rich fraction. The purity of the meta-xylene produced is at least 99.5%.

Abstract: A process for producing para-xylene from a hydrocarbon feed is described in which an adsorption column operating as a simulated moving bed with at least five zones delivers an extract, a 2-raffinate and an intermediate raffinate. The extract is distilled and the distillate is optionally re-crystallized to recover para-xylene with a purity of at least 99.7%. The 2-raffinate is distilled then isomerized in a reactor preferably operating in the liquid phase and at a low temperature. The intermediate raffinate with an enriched ethylbenzene content is distilled then isomerized in the vapour phase.

Abstract: Process for separation of metaxylene, with at least 99% by weight of purity of an aromatic feedstock F, in a single adsorption stage in a simulated moving bed in an SMB device that comprises 12, 13 or 15 adsorbent beds with different numbers of beds being employed in zone 1 between the supply of the desorbent D and the draw-off of the extract E; zone 2 between the draw-off of the extract E and the supply of the feedstock F; zone 3 between the supply of the feedstock and the draw-off of the raffinate R; and zone 4 between the draw-off of the raffinate R and the supply of the desorbent D whereby the process is carried out according to a configuration of zones (a, b, c, d), whereby a, b, c, and d represent the number of adsorbent beds that operate respectively in zones 1, 2, 3, 4 in which there is used: Either an SMB of 12 adsorbent beds operating according to the configuration (2, 5, 3, 2), Or an SMB of 13 adsorbent beds operating according to the configuration (2, 5, 4, 2), Or an SMB of 15 adsorbent beds op

Abstract: A process for separating a feed F by simulated moving bed adsorption in a SMB device is described, the device comprising external bypass lines Li/i+1 which directly connect two successive plates Pi, Pi+1, the index i being either even or (exclusive of the foregoing) odd, along the whole length of the column, in order to flush said plates, in which each of the bypass lines Li/i+1 comprises automated means for regulating the flow rate in the bypass lines, the degree of opening of said regulating means being defined by the following three rules: a) establishing a flow rate corresponding to an oversynchronicity in the range 15% to 30% in all of the open bypass lines of zone 1; b) establishing a flow rate corresponding to the synchronicity to within plus or minus 8% in all of the open bypass lines of zones 2 and 3; c) establishing a flow rate corresponding to an oversynchronicity in the range 20% to 40% in all of the open bypass lines of zone 4.

Abstract: Process for separating paraxylene with a purity that is at least equal to 99.5% by weight from an aromatic feedstock F in a single adsorption stage in a simulated moving bed (SMB), comprising different numbers of beds, allocated to a zone 1 between the supply of the desorbent D and the draw-off of the extract E; a zone 2 between the draw-off of the extract E and the supply of the feedstock F; a zone 3 between the supply of the feedstock and the draw-off of the raffinate R; a zone 4 between the draw-off of the raffinate R and the supply of the desorbent D, wherein an SMB of 12 adsorbent beds has bed configuration (2, 5, 3, 2), an SMB of 15 adsorbent beds has bed configuration (3, 6, 4 , 2), or an SMB of 19 adsorbent beds has bed configuration (4, 7, 6, 2), wherein the desorbent in this latter case is paradiethylbenzene.

Abstract: The invention concerns a process for separating meta-xylene from a hydrocarbon feed comprising isomers containing 8 carbon atoms, comprising: a step for bringing said feed into contact with a faujasite type zeolite adsorbant, the percentage of water in the adsorbant being in the range 0 to 8% by weight and the adsorption temperature being from 25° C. to 250° C.; a desorption step employing a solvent selected from tetraline and its alkylated derivatives; a step for separating meta-xylene from the desorbant.

Abstract: The present invention relates to agglomerated zeolitic adsorbents based on zeolite X with an Si/Al ratio such that 1.15<Si/AL<1.5, consisting of crystals with a mean diameter of 1.7 mm or less and of an inert binder, at least 90% of the exchangeable cationic sites of the zeolite X being occupied by barium ions. They may be obtained by agglomerating a zeolite X powder having a mean diameter of 1.7 mm or less with a binder, followed by zeolitization of the binder, exchange of the zeolite ions with barium (and potassium) ions and activation of the adsorbents thus exchanged.

Abstract: A process for separating propylene mixed with propane by adsorption in a simulated moving bed is described. The process operates in the gaseous phase or in the liquid phase, and it uses a 13X faujasite-type zeolite as adsorbent solid and butene-1 or isobutane or any mixture of these 2 components as desorbent.

Abstract: Process for separation of a feedstock F by adsorption in a simulated moving bed in an SMB device that comprises a zone 1 for desorption of compounds produced by extraction, a zone 2 for desorption of compounds produced with a raffinate, a zone 3 for adsorption of compounds produced by extraction, and a zone 4 that is located between the draw-off of the raffinate and the supply of the desorbent, whereby the device comprises external bypass lines Li/i+1 directly joining two successive plates Pi, Pi+, that are equipped with non-automated means for adjusting flow rate and closing means, in which the degree of opening of the restriction means of the scavenging flow rate of the bypass lines Li/i+1 is adjusted so as to obtain the best performance of the SMB.

Abstract: A process for co-producing para-xylene and styrene from a feed (1) of hydrocarbons containing xylenes and ethylbenzene is described, the process comprising the following succession of steps: a step for separating the feed in a simulated moving bed in an adsorption column (6) containing beds of an adsorbent, from which an extract that is rich in para-xylene (7a) of at least 99.7% purity and at least one raffinate (7b) containing ethylbenzene, ortho-xylene, meta-xylene and a very small quantity of para-xylene is withdrawn; a step for dehydrogenating (10) the ethylbenzene contained in the raffinate (7b) to styrene; at least one step for primary separation of the stream (11) from the dehydrogenation step (10), to eliminate by-products; a step for separating the purified mixture (18) derived from the stream (11) containing styrene, unconverted ethylbenzene, meta-xylene and ortho-xylene, from which a stream (21a) that is rich in styrene of at least 99.

Abstract: The invention concerns a simulated moving bed (SMB) separation device and process comprising a column, beds Ai of adsorbent separated by plates Pi with a single distribution and extraction network for fluids, in particular feed F, desorbant D, raffinate R and extract E, and a plurality of two-way valves for distribution of said fluids, said valves being limited in number and in particular with dimensions that are smaller than in the prior art. According to the invention, the column is divided into a plurality of sectors Sk with 2 superimposed plates, each sector Sk comprising an external principal bypass line Lk connected to each plate P1 of Sk via a large diameter plate valve V1 and an external secondary bypass line Mk comprising a small diameter valve VMk connected to the adjacent sector Sk?1.

Abstract: The invention concerns a simulated moving bed adsorption separation device comprising a limited number of valves. According to the invention, the device comprises a column with a plurality of sectors Sk with 2 superimposed plates Pi with a single distribution network, each sector Sk comprising an external principal bypass line Lk connected to each plate Pi of Sk via a plate valve Vi. Each line Lk comprises a flow limitation means and is connected to each of the fluid networks via a single valve. Further, the connectors of lines Lk onto the column are offset by at most 20° inside Sk to limit the volume of lines Lk, and are offset by a mean angle in the range 70° to 110° between two neighbouring sectors Sk and Sk+1 so as not to weaken the column mechanically. The plates preferably comprise panels DMEi,j with parallel segments the direction of which varies from plate to plate or per group of 2 plates.