Simulated mobile layer separation process and device with reduced number of larger diameter valves

Abstract

MOBILE LAYER SEPARATION PROCESS AND DEVICE SIMULATED WITH NUMBER OF LARGER LARGER DIAMETER VALVES. The invention relates to a simulated mobile layer separation device (SMB), comprising a column, layers of adsorbent A ~ i ~ separated by plates P ~ i ~ with a unique network of distribution and extraction of fluids, in particular of charge F, desorbent D, refined R and an extract E, and a plurality of 2-way valves for the distribution of these fluids, these valves being in a limited number, and above all smaller in size than in the prior art. According to the invention, the column is divided into a plurality of sections S ~ k ~ with 2 overlapping plates, each section S ~ k ~ comprising a main external bypass line L ~ k ~ connected to each plate P ~ i ~ de S ~ k ~ by a larger diameter V ~ i ~ plate valve and a secondary external bypass line M ~ k ~, comprising a smaller diameter V ~ MK ~ valve connected to the adjacent sector S ~ kl ~ Each line L ~ k ~ comprises a means of limiting flow, and is connected to each of the fluid networks F, D, R, E via a single valve of larger diameter for feeding or sequential stretching of the corresponding fluid F, D, R or E to or from the section S ~ k ~. The invention also relates to a separation process, using this device. Figure 2 to be published.

Description

(54) Title: DEVICE, WHICH ALLOWS SEPARATION OF AT LEAST ONE COMPOUND FROM A MIXTURE COMPRISING THAT COMPOUND BY ADSORPTION IN A SIMULATED MOBILE LAYER AND ITS SEPARATION PROCESS FROM A PRODUCT USING SAID DEVICE (51) Int.CI.: B01D 15 / 08 (30) Unionist Priority: 16 / 10 / 2006 FR 06 09192 (73) Holder(s): IFP (72) Inventor(s): PHILIBERT LEFLAIVE; SYLVAIN LOURET; GÉRARD HOTIER; FRÉDÉRIC AUGIER 1 / 28 Descriptive Report of the Invention Patent for a DEVICE THAT ALLOWS THE SEPARATION OF AT LEAST ONE COMPOUND FROM A MIXTURE COMPRISING THAT COMPOUND BY ADSORPTION ON A SIMULATED MOVING LAYER AND ITS SEPARATION PROCESS FROM A PRODUCT USING SAID DEVICE. FIELD OF THE INVENTION

[001] The present invention relates to the field of separations of natural or chemical products that can hardly be separated by distillation.

[002] A family of processes, and associated devices, known as processes, are then used.or chromatographic separation devices or moving layer devices; Simulated, or simulated countercurrent, or simulated cocurrent”, which will be referred to hereinafter as SMB.

[003] The domains referred to are notably, but not exclusively: - the separation between, on the one hand, normal paraffins and, on the other hand, branched paraffins, naphthenes and aromatics; - the separation of olefins / paraffins; - the separation of paraxylene from other C8 aromatic isomers; - the separation of metaxylene from other C8 aromatic isomers; - the separation of ethylbenzene from other C8 aromatic isomers.

[004] Outside the refinery and petrochemical complex, there are numerous other applications, among which we can mention glucose / fructose separation, the separation of positional isomers of cresol, optical isomers, etc. 4 / 43 2 / 28 PRIOR TECHNIQUE

[005] Chromatographic separation SMB is well known in the state of the art.A simulated moving layer comprises at least three chromatographic zones, advantageously four, five, or six zones, each of these zones consisting of at least one layer or part of a column and comprised between two successive feed or stretch points. Typically, at least one feed F to be fractionated and a desorbent D (sometimes called a purifier) ​​are fed, and at least one raffinate R and an extract E are stretched. Sometimes, a reflux RE rich in extract is also fed. It is also possible to use not one raffinate R, but two raffinates R1 and R2. There are therefore generally 4, 5, or 6 process fluids, fed or stretched sequentially. The feed and stretch points are modified over time, offset in the flow direction and typically down a layer and thus synchronously.

[006] Many advantageous variants allow for improved operation of this type of unit.resorting to asynchronous permutations.

[007] In simplified terms, these asynchronous permutations serve to compensate for the dead volume(s) of the recirculation pump(s), as indicated in US patent 5,578,215, working with a constant recycling flow rate on the recirculation pump, in order to eliminate flow and pressure markings, as indicated in US patent 5,762,806, or finally operating with at least two chromatographic zones, each equivalent to a non-integer number of adsorbent layers. This last variant, as indicated in US patents 6,136,198, 6,375,839, 6,712,973 and 6,413,419, is known as Varicol. Naturally, these three variants can be combined. Petition 870180010737, dated 07 / 02 / 2018, page 5 / 43 3 / 28

[008] It should be noted that a multi-way rotary valve, placing in communication, on the one hand, the fluids that enter and exit, and, on the other hand,The layers arranged in the adsorption column(s) allow only synchronous exchange. For asynchronous exchanges, a plurality of valves, total or not, is indispensable. This technological aspect is discussed later.

[009] The state of the art describes in detail different devices and processes that allow the separation of charges in a simulated moving layer. Notably, patents US 2,985,589, US 3,214,247, US 3,268,605, US 3,592,612, US 4,614,204, US 4,378,292, US 5,200,075, and US 5,316,821 can be cited. These patents also describe in detail the operation of an SMB.

[0010] SMB devices typically comprise at least one column (and often two), layers of adsorbent Ai arranged in that column, separated by plates Pi with chamber(s) Ci for distributing and / or extracting fluids into or from the different adsorbent layers,and sequential fluid distribution and extraction control means.

[0011] Each of the Pi plates typically comprises a plurality of distribution-mixing-extraction or DME plates fed by distribution / extraction lines or hooks. The plates can be of any type and any geometry, notably with plates forming adjacent sectors of the column section, for example, plates with angled sectors, such as those shown in US patent 6,537,451, figure 8, which are symmetrical (hook) feed, or parallel sectors, such as those cut in a circumference, as indicated in published US patent application 03 / 0,127,394, which are asymmetrical feed. Preferably, the separation column comprises DME plates of the type with Petition 870180010737, dated 07 / 02 / 2018, page 6 / 43 4 / 28 parallel sectors and asymmetrical feeds. Also preferably,The adsorbent is installed in dense loading. This allows for the use of a greater quantity of adsorbent in a given column, and increases the purity of the desired product and / or the SMB feed rate.

[0012] Distribution over each layer requires collecting the flow from the preceding layer (main fluid circulating along the main axis of the column), the possibility of injecting an ancillary or secondary fluid, mixing these two fluids as much as possible, or even the possibility of removing a portion of the collected fluid, extracting it to send it outside the device and also redistributing fluid over the next layer.

[0013] For this, distribution chambers (injection / extraction) can be used in Pi plates, which can be separate or common with mixing chambers. Pi plates with one or more chambers are known, whether fed (or stretched) separately by different fluids at a given instant,are fed (or stretched) simultaneously in parallel by the same fluid at a given instant. In the first case, the plate is said to be in multiple distribution networks, while in the second case it is in a single distribution network. The invention relates exclusively to a device comprising single distribution network plates.

[0014] In general, it is possible either to pass the entirety of the fluid or main flow in the column, according to a scheme described in US patent 2,985,589, or to protrude a large part or all of this flow to the outside according to a process described in US patent 5,200,075.

[0015] A generic problem of the SMB device set is to minimize the pollution generated by the liquid that is in the different zones and volumes of the feeding and stretching circuits of the plates,when modifications to the feed and stretching points occur during the operation of the SMB. In effect, when, during the operating sequence, a feed line, chamber, or zone of a Pi plate is not swept by a process fluid, it becomes a dead zone, in which the liquid stagnates, and is only set in motion again when another process fluid circulates there. As, due to the operation of the SMB, a different process fluid is then involved, the liquid in the dead zone is necessarily displaced by a liquid of noticeably different composition. The mixing, or circulation with a short time interval of fluids of noticeably different compositions, therefore introduces a disturbance in relation to the ideal operation, for which compositional discontinuities should be avoided.

[0016] Another problem may lie in the eventual recirculations between different zones of the same plate,which then also induces a disturbance in relation to the ideal functioning.

[0017] To solve these problems related to recirculations and dead zones, different techniques are known from the previous technique: a) it has been proposed to perform a sweep (the English word flush is also frequently used) of the lines and dead zones with notably desorbent or the desired product, relatively pure. This technique effectively avoids pollution of the desired product during its extraction. However, as the sweep liquid typically has a very different composition from the liquid that is displaced, this introduces compositional discontinuities that are detrimental to ideal functioning. This first variant of sweeping typically performs short-duration sweeps with a high concentration gradient. These sweeps are short-duration to limit the effects of compositional discontinuities; Petition 870180010737, dated 07 / 02 / 2018, page 8 / 43 6 / 28 b) another solution consists,As described in US patent 5,972,224, a majority of the main flow is diverted into the column, and a minority of that flow is diverted to the outside, typically 2% to 20% of the flow, through external bypass lines between adjacent plates. This sweeping is typically done continuously most of the time, so that the lines and zones are no longer dead, but swept. This system with bypass line sweeping is shown in Figure 1 of US patent 5,972,224 and is reproduced in a simplified form in Figure 1 of the present application. As the bypass lines are designed for a small flow rate, they can consequently be of smaller diameter and include a smaller diameter valve, which reduces the cost of the system.

[0018] A first advantage of this system is that the injection and withdrawal circuits of the secondary fluids are swept by liquid that has a composition very close to that of the displaced liquid, since, on the one hand,The diversion originates from the neighboring plate, and, on the other hand, there is not a point sweep, but a noticeably continuous one. Furthermore, the flow rates in the diversions are preferably determined so that the transit velocity in each diversion is approximately the same as the velocity of the concentration gradient in the main flow of the SMB. Thus, on the one hand, a sweep of the different lines and capacities is carried out by a fluid that has a composition approximately identical to that of the liquid that is there, and, on the other hand, the liquid circulating in a diversion is reintroduced at a point where the composition of the main flow is approximately identical. This second variant therefore performs long-duration sweeps with a weak or zero concentration gradient.

[0019] A second advantage of this long-duration sweep system (excluding injection or stretching periods) is that it allows suppressing the effects of possible recirculations between zones of Petition 870180010737,From 07 / 02 / 2018, page 9 / 43 7 / 28 the same plate, due to small differences in pressure losses.

[0020] Regarding the operation of an SMB, the controlled means of fluid distribution and extraction of an SMB are typically one of the following two major types of technology: - either, for each plate a plurality of valves controlled in whole or in part for the supply or stretching of fluids, these valves typically being located in the immediate vicinity of the corresponding plate, and notably comprising, for each plate Pi, at least 4 valves controlled in whole or in part with two ways for respectively the supply of fluids F and D and the stretching of fluids E and R; - either a multi-way rotary valve for the supply or stretching of fluids over the set of plates.

[0021] The first technology uses valves with 2 ways,which allows for standard mass production leading to increased reliability and a relatively low unit cost. The second technology uses only a single valve, but this single valve is multi-way (accommodating more than 2 ways), and necessarily of special construction, large size and high complexity. Furthermore, this second technology excludes the possibility of asynchronous permutations, as in Varicol devices.

[0022] The invention relates to SMBs, using conventional 2-way valves, that is, using the first of the two technologies described above. It refers, in particular, to an improved simulated moving layer separation device, comprising a plurality of 2-way valves, with the number of controlled valves generally somewhat reduced, and, above all, in a notably reduced number for the controlled valves with the largest opening diameter,in relation to the previous technique. It is usable for both an SMB with synchronous permutations and an SMB with asynchronous permutations, for example, a Varicol. SIMPLIFIED DESCRIPTION OF THE INVENTION

[0023] The invention relates to an improved simulated moving layer separation device belonging to the large technological type of SMBs, using a plurality of controlled valves (fully or not at all or with progressive opening) with 2 ways, typically standard valves manufactured in series at a reduced cost for a high level of quality (tightness / reliability) required.

[0024] One of the essential purposes of the invention is to reduce the relative inconvenience of this type of SMB which is to require a large number of controlled valves with 2 ways of larger diameter, i.e.of an opening diameter compatible with the circulation of the SMB process fluids with the respective nominal flow rate. The invention typically allows a notable reduction in the number of larger diameter controlled valves, while retaining the advantage of being able to use an effective long-duration dead zone sweep with low or zero concentration gradient.

[0025] Another purpose of the invention is to present a device that requires a reduced number of larger diameter (opening) 2-way valves, without these valves having an increased opening / closing frequency compared to the prior art solution, which, considering the reduced number of larger diameter valves, limits the statistical risks of malfunction and increases the reliability of the system.

[0026] Finally,A preferred variant of the device allows for a further reduction in the number of larger diameter valves that allow the circulation of the main fluids of the SMB at their nominal flow rate.

[0027] The device, according to the invention, can be used on new installations, but is also compatible with various existing installations on which it can be installed, making limited modifications. It is also compatible with various types and geometries of Pi plates, for example plates with angular or parallel sector panels, as long as these plates (or most of them) are of the single distribution network type, for the sequential feeding or stretching of a process fluid from the SMB.

[0028] Therefore, a means has been discovered that allows for a significant reduction in the number of larger diameter main controlled valves,corresponding to the sequential inputs and outputs of the SMB process fluids with their nominal flow rate: in the previous technique, there is at least one set of 4 main network valves for each tray for the feeds / stretches of F, D, R, E. This number will be further increased if there are more than 4 process fluids for the SMB, for example, if there are 2 refined products R1, R2 and / or if a reflux RE rich in the researched product is used, typically extracted from there. Therefore, there are as many larger diameter controlled valves per tray as there are process fluids in the SMB, most frequently between 4 and 6, inclusive limits.

[0029] The smaller diameter diversion lines are only attached lines in the prior art that are used by fluids F, D, R, E (E1), (E2) (RE) with their nominal feed or draw flow rate, but at a noticeably lower flow rate, typically less than 20% of the flow rate circulating in the column, often between 2 and 10% of that flow rate. They therefore comprise,typically a progressive opening control valve (for sweep flow control) with a smaller opening diameter (or equivalent diameter of the same passage section).

[0030] According to the invention, the column, or a main part (more than 50% of the column height at least) of that column is grouped into superimposed Sk sections, each Sk section comprising two successive layers of adsorbents Ai, Ai+1, and the 2 Pb Pi+1 plates situated immediately below these layers, and also comprising a main bypass line Lk. In contrast to the previous technique, the Lk diversion line is used for SMB fluids at their nominal flow rate (and not just at a lower sweep flow rate) and a single set of main network valves (sequential feed or extension) is used per column section (for 2 trays and not per tray as in the previous technique).These larger diameter valves are connected to the bypass line Lk in order to allow the circulation of these fluids via Lk.

[0031] According to the invention, plate valves are provided, either a larger diameter valve, respectively V1 or Vi+1, for each of the plates Pi, Pi+1 of Sk, as well as additional means of limiting the smaller flow rates of sweep fluid circulating in Lk. According to the invention, a secondary bypass line Mk is also provided, connecting the Sk sector to the immediately lower adjacent sector Sk+1. This allows excellent sweeping of the SMB plate assembly and tends to improve the purity of the recovered product, typically the extract.

[0032] As will be explained below, notably for the description of Figure 2, which allows for a easier understanding of the invention, the total number of larger diameter controlled valves is reduced.

[0033] The invention also relates to an SMB separation process, using the device thus described,notably for the separation of an aromatic, in particular paraxylene or metaxylene from a load of aromatic hydrocarbons with 8 carbon atoms.

[0034] The invention also relates to an SMB separation process, using the device thus described, notably for the separation of a normal paraffinic hydrocarbon, or an olefinic hydrocarbon from a cut comprising that hydrocarbon. DETAILED DESCRIPTION OF THE INVENTION

[0035] The invention will be better understood by reading the following description and consulting Figures 1 (prior art) and Figures 2 and 3 (device according to the invention).

[0036] To achieve one of the aforementioned purposes, a device has therefore been proposed, according to the invention, that allows the separation of at least one compound from a mixture comprising that compound by adsorption on a simulated mobile layer,comprising: - at least one column comprising a plurality of adsorbent layers Ai separated by distributor / extractor plates Pi for the sequential feeding and extraction of at least two feed fluids: a feed F and a desorbent D, and at least two stretching fluids: a raffinate R and an extract E, Pi being disposed between layer Ai and the immediately lower layer Ai+1; - the device also comprising at least one feed F-Net, one desorbent D-Net, one raffinate R-Net and one extract E-Net, each of these networks being connected to the column by a plurality of lines comprising 2-way controlled shut-off valves with an opening diameter greater than or equal to a value α, referred to as net valves, for the sequential feeding or stretching of these feed or stretching fluids;

[0037] in which the column is divided,over most of its height, at least in a plurality of adjacent superimposed sections Sk, each section Sk being essentially constituted by 2 successive adsorbent layers Ai, Ai+1 and by the 2 distributed plates. Petition 870180010737, dated 07 / 02 / 2018, page 1. 14 / 43 12 / 28 distributors / extractors P,, Pi+1 which are arranged respectively immediately below A, and Ai+1,

[0038] each of the distributor / extractor plates Pb Pi+1 of each of the sectors Sk is of a single common network for the sequential feeding and stretching of F, D, R, E, the Pb Pi+1 plates of each Sk section are connected to each other by a main external bypass line Lk connected to each of the Pb Pi+1 plates of Sk by a fitting comprising a unique 2-way controlled sectioning valve specific to that Pb Pi+1 plate called plate valve V,,or Vi+1 of an opening diameter greater than or equal to the value α for the sequential feeding or stretching of these feed or stretching fluids into or from Pi,

[0039] each of these Lk bypass lines comprises at least one controlled means of limiting the flow circulating in Lk that is either installed on the Lk line, either bypassing a disc valve V,, or Vi+1 of a Sk disc,

[0040] wherein the Lk bypass line of each of the Sk sections is connected to each of the F-Net, D-Net, R-Net, E-Net networks via a single line of internal diameter greater than or equal to α, comprising a single network valve, respectively VFk, VDk, VRk VEk, which is of an opening diameter greater than or equal to α, for the sequential feeding or stretching of the corresponding fluid F, D, R or E into or from the Sk section considered, the device also comprising a plurality of lines secondary external deviations Mk,each of the Mk lines connecting the 2 adjacent sectors Sk-1 and Sk via 2 connection points;

[0041] the first connection point being disposed on the tip connected to the lower plate Pi-1 of the upper sector Sk-1 between Pi-1 and the plate valve Vi-1,

[0042] the second connection point being disposed on the tip connected to the upper plate P, of the lower sector Sk between P, and the plate valve V,,

[0043] each of the secondary external bypass lines Mk comprising a 2-way controlled valve VMk of internal opening diameter less than or equal to a value β, with β < 0.6 α.

[0044] Typically α and β are chosen to check the following inequality: 30 mm < 1.7 X β < α < 600 mm. It can be seen that VMk valves with an internal opening diameter less than or equal to β are much smaller and less expensive than valves with an internal opening diameter greater than or equal to α.

[0045] Unlike the device,According to the prior art, the device, according to the invention, allows the use of the bypass line Lk for the circulation of fluids F, D, R, E (and preferably other eventual process fluids) fed into the SMB and drawn from the SMB to the level of section Sk, via a single set of corresponding network valves, instead of a set of network valves per plate P, according to the prior art. This allows a reduction in the overall number of larger diameter controlled valves, even considering the addition of supplementary valves, namely the plate valves V, as will be shown below, when describing figures 2 and 3.

[0046] The aforementioned controlled valves: network valves and plate valve V, are typically high-quality valves (reliability, tightness, service life) performing the sequential operation of the SMB.

[0047] More generally, all controlled valves ensuring the sequential operation of the SMB: network valves,Valves V, plate valves, and also valves of the controlled means of limiting the flow circulating in Lk should be considered, according to the invention, as the main valves of the SMB, connected to the colluPetition 870180010737, dated 07 / 02 / 2018, page 16 / 43 14 / 28 and controlled by the sequential operation control system of the SMB (computer, programmable logic controller or other equivalent system).

[0048] Certain main valves of the sequential operation of the SMB were previously mentioned as being unique according to the invention: Lk for each plate Lk; unique set of network valves VFk, VDk, VRk, VEk... for each section Sk. These valves are exclusively those that allow the sequential operation of the SMB. However, it would not fall outside the scope of the invention if, in addition, other valves were used, such as secondary valves for occasional isolation, typically of much lower quality, whether controlled or not.but not participating in the sequential operation of the SMB and allowing, for example, the disassembly of any equipment: pump or main valve used for sequential operation, etc.

[0049] Typically, the bypass line Lk that is used for the transit of all fluids F, D, R, E,... with their nominal flow rate is no longer, in the device according to the invention, a small attached line as in the prior art, but generally has an internal diameter at least equal to the largest opening diameter of the network valves connected to Lk, so as to be able to circulate fluids F, D, R, R at their nominal flow rate, without capacity limitation. The nominal flow rate of a process fluid is, by definition, the controlled flow rate of that fluid, which is used during the sequential operation of the SMB, for the desired separation.

[0050] Due to the use of bypass lines Lk capable of conveying relatively significant nominal flow rates,Controlled flow limitation devices are advantageously used to also perform bypass circulations in Lk with low flow (typically 20% of the flow circulating in the column). The term bypass circulation means that a (small) fraction of the flow circulating in the column is drawn from one plate and reintroduced onto another plate of the same Sk section. The term controlled devices typically applies to a controlled valve, typically by means of a regulating chain, based on information provided by a flow meter.

[0051] A flow control valve installed directly on the Lk line can be used for this purpose, as shown in Figure 3. This valve is typically a progressive opening valve with a larger diameter, and not a fully or partially controlled valve (having only two possible positions: fully open and closed).

[0052] However,According to a preferred variant of the invention, represented in Figure 2, at least one, or preferably each of the bypass lines Lk, comprises a controlled flow-limiting means circulating Lk, which is not installed directly on Lk, but bypassed around a plate valve of a plate Sk, for example, around the plate valve Vi+1 of the lower plate Pi+1. This flow-limiting means, disposed on a small attached bypass Ik, generally comprises a controlled valve Vi+1, with a smaller opening diameter than that of Vi+1, for example, with an opening diameter at most equal to 60%, or 50% of that of Vi+1, for example between 10% and 50% of the opening diameter of Vi+1.

[0053] The valve Vi+1 is typically of an opening diameter less than or equal to β and frequently less than or equal to half of α. The sizing of this sweep flow control valve is, in effect,advantageously the same as that of the VMk valve located on Mk. In both cases, it is a matter of ensuring the regulation of a limited sweep flow. Thus, in the same way, each of the secondary diversion lines Mk typically comprises at least one controlled means of limiting the flow circulating in Mk, this means comprising the VMk valve.

[0054] When it is desired to perform an internal sweep via Lk and limit this internal flow (which typically circulates from the upper plate Pi of Sk to the lower plate Pi+1 of Sk), the plate valve Vi+1 is left closed, the smaller bypass valve Vj+1 is opened around Vi+1, this valve Vi+1 operating in flow control, and Vi is opened, thus allowing the circulation of a limited sweep flow originating from Lk and recycled in Pi and recycled in Pi+1 via Lk and Ik (see figure 2).

[0055] Thus,The use of a small attached bypass Ik allows the use of a valve with a smaller opening diameter than if the flow limiting device were installed over the main bypass line Lk, which is relatively larger in diameter, due to the fact that Lk must allow the circulation of fluids F, D, R, E,... at their nominal flow rate.

[0056] According to the invention, the nozzle comprising Vi+1 should be interpreted as not comprising the small secondary bypass Ik around Vi+1, nor the small valve Vi+1 disposed over Ik. This nozzle therefore comprises a single valve Vi+1, allowing the circulation of the main fluids F, D, R, E...

[0057] Typically, the bypass line Lk has an internal diameter at least equal to the largest opening diameter of the network valves connected to Lk. Thus, the diameter of Lk does not constitute a flow limitation in relation to the opening diameter of the network valves directly connected to Lk.

[0058] Preferably,The entire column (except for the head plate, excluded by the chosen definition of the word section) is constituted by the adjacent superimposed sections Sk. In this case, according to the invention, the lower outlet line at the bottom of the column is assimilated to a plate Pn corresponding to the lower adsorbent layer An. In effect, there is typically no plate Pn below the adsorbent layer An arranged at the bottom of the column, as there is no need to distribute the fluids in an immediately lower layer. Also, according to the invention, in this case, the missing plate Pn is considered to be replaced by the lower outlet line of the column, typically connected either to the inlet of the same column, via a recirculation pump, or to the head of a second separation column.

[0059] As mentioned, the SMB can operate with a reflux RE comprising the extract, or typically rich in the researched product obtained,distilling the extract to eliminate the desorbent (comprising more than 50%, or even 90% or even 99% of the researched product). Preferably, the device, according to the invention, then comprises a sequential reflux feed network RENet, this network being connected to each of the Sk sectors via a single line of internal diameter greater than or equal to α, comprising a single-network valve VREk that is of opening diameter greater than or equal to α. Thus, the reflux network is connected in an identical manner to those of the other process fluids F,D,R,E.

[0060] Similarly, the SMB can also operate with a sequential stretching of a second refined R2 and, in that case, the device according to the invention preferably comprises an R2-NET network connected to each of the Sk sectors via a single line with an internal diameter greater than or equal to α, comprising a single-network valve VREk that has an opening diameter greater than or equal to α. Thus,The second refining network is connected in the same way as those of the other process fluids F, D, R, E (RE).

[0061] The invention also relates to a product separation process using a device as described above. Typically, during a cycle: Petition 870180010737, dated 07 / 02 / 2018, page 20 / 43 18 / 28 - each of the Lk lines is used sequentially for circulation with its nominal flow rate of F, D, R, E, and optionally a reflux RE and / or a second refining R2 to or from each of the Sk trays via the corresponding tray valve and the corresponding network valve in series; - A sweep is performed with a flow rate lower than the nominal flow rates of fluids F, D, R, E, and optionally RE and / or R2, of each of the main external bypass lines Lk during at least part of the time in which no network valve connected to Lk is open,by an internal current originating from one plate of the device and recycled towards another plate of the device, and any internal sweep of Lk is stopped when a network valve connected to Lk is opened; - a sweep is performed with a flow rate lower than that of the nominal flow rates of fluids F, D, R, E of each of the secondary external bypass lines Mk for at least part of the time, by an internal current originating from one plate of the device and recycled towards another plate of the device.

[0062] The process, according to the invention, therefore uses the SMB device, effectively performing the sweeps by circulation from plate to plate via the bypass lines Lk and Mk. Typically, the sweep of Lk is performed by circulation of a current originating from the upper plate Pi of Sk, recycled in the lower plate Pi+1 of Sk.

[0063] Typically also, the sweep of Mk is performed by circulation of a current originating from the lower plate Pi+1 of Sk-1,recycled in the upper plate Pi of Sk.

[0064] Generally, an internal Lk sweep is performed, from the upper plate Pi of Sk towards the lower plate Pi+1 of Sk in any period or Sk is not connected to one of these sequential feed or sequential stretch fluid networks and is found Petition 870180010737, dated 07 / 02 / 2018,pg. 21 / 43 19 / 28 immediately before a period or one of the network valves connected to Sk is opened for feeding or stretching one of these fluids towards or from the upper plate Pi. This internal sweep leads to the opening of V1 in the period preceding a feeding or stretching period of the plate Pi (which also requires the opening of V1) and avoids an opening or closing movement of V1 between these consecutive periods. Reducing the number of valve movements reduces wear on these valves and increases the reliability of the device and the associated process.

[0065] Internal sweeps are performed on at least two and typically all of the Lk bypass lines. Generally, for a given Lk (or Mk) line, the internal sweep lasts at least 20%, often at least 40%, or even at least 50% of the time.

[0066] Preferably, for each of the Lk bypass lines, an Lk sweep,

[0067] Typically, Lk is used by each of the fluids F, D, R, E over its entire length during a cycle. This avoids any dead zone in Lk.

[0068] The disc valves Vi-1 and V1 of the ferrules connected by a secondary external bypass line Mk are preferably closed when performing a sweep of Mk. This prevents partial mixing of the sweep flow with the fluid in Lk.

[0069] A sweep of Mk can be performed during the entire time that the disc valves Vi-1 and V1 of the ferrules connected by the secondary external bypass line Mk are closed.

[0070] According to a process variant of the invention, asynchronous permutations of the feed and draw points of fluids F, D, R, E in the column are performed. Petition 870180010737, dated 07 / 02 / 2018,pg. 22 / 43 20 / 28

[0071] The device can also be used with chromatographic zones which are at least equivalent to a non-integer number of adsorbent layers, typically in Varicol.

[0072] The invention is not connected to a particular separation, but can be used for all simulated moving layer separations. For example, a separation process of an aromatic hydrocarbon, for example, paraxylene or metaxylene, from a feedstock of aromatics having essentially 8 carbon atoms and comprising that hydrocarbon can be carried out.

[0073] A separation process of at least one normal-paraffinic hydrocarbon from a feedstock of hydrocarbons comprising that hydrocarbon, or a separation process of at least one olefinic hydrocarbon from a feedstock of hydrocarbons, can also be carried out.understanding this hydrocarbon. DESCRIPTION OF THE FIGURES AND OPERATION OF THE DEVICES REPRESENTED

[0074] The invention will be easily understood by following the description of the attached figures, in which:

[0075] Figure 1 schematically represents a part of an SMB device, according to the prior art, with the corresponding network valves.

[0076] Figure 2 schematically represents a part of an SMB device, according to the invention, comprising three superimposed sections Sk, Sk+1, Sk+2, with the main and secondary diversions, the network valves, the disc valves and the corresponding flow limiting valves.

[0077] Figure 3 schematically represents a part of an SMB device, according to the invention, comprising flow limiting valves located on the lines Lk, Lk+1 themselves. Petition 870180010737, dated 07 / 02 / 2018, page 23 / 43 21 / 28

[0078] reference will be made to figure 1 below,representing a section of a chromatographic column of an SMB, according to the previous technique. Each of the adsorbent layers P1, Pi+1, Pi+2, Pi+3, Pi+4, Pi+5 and each of these plates is connected by a line, respectively 3, 4, 5, 6, 7, 8 to each of the 4 fluid networks F, D, R, E by a valve (not referenced). There are therefore 4 main valves per plate. In addition, the plates are connected two by two by a bypass line 1a, 1b, 1c, typically of relatively smaller diameter, and comprising a valve of relatively smaller diameter (less than or equal to a β value), respectively 2a, 2b, 2c to allow the passage of a limited bypass flow rate: 2% to 20% of the flow rate circulating in the column.

[0079] In total, for each plate 1, there are 4 main valves with a relatively larger opening diameter, greater than or equal to a value α > β (compatible with the nominal flow rates of F, D, R, E) and on average 0.5 valves with a smaller diameter (one for every 2 plates), that is, on average 4.5 valves per plate,of which four of which have a larger diameter opening, greater than or equal to α.

[0080] The operation of an SMB using this column is well known to the technician. Typically, valve 2a, or 2b, or 2c of a bypass line is open, and regulates a limited sweep flow, when no fluid F, D, R, E is fed or drawn from one of the 2 plates connected by the bypass line (bypass temporarily in service). Conversely, valve 2a, or 2b, or 2c of a bypass line is closed when one of the fluids F, D, R, E is fed or drawn from one of the 2 plates connected by the bypass line (bypass temporarily out of service).

[0081] Figure 2 represents a column portion of a device according to the invention, comprising 3 sections Sk, Sk+1, Sk+2, each comprising two layers of adsorbent and 2 plates located immediately below. The 2 plates of each section are connected by a main diverter line,of relatively larger diameter, typically greater than or equal to α, respectively Lk, Lk+1, Lk+2, which is suitable for the circulation of fluids F, D, R, E,... with their nominal flow rate. Each bypass line is connected to a set of 4 network valves of relatively larger diameter opening, greater than or equal to α for sequential feeding and stretching of process fluids. Contrary to the previous technique, this set of 4 network valves feeds not 1, but 2 plates.

[0082] Thus, for the first section Sk, there are 4 network valves V1, V1, V1, V1 feeding Pi and Pi+1 at the same time.

[0083] Each plate is, on the other hand, connected to the corresponding bypass line Lk, or Lk+1, or Lk+2 by a ferrule (corresponding to the horizontal line portion in the figure) comprising a unique 2-way controlled shut-off valve specific to the plate, called a plate valve: Vi, Vi+1, V1+2, Vi+3, V1+4, V1+5. Each lower plate valve of a section: Vi+1, Vi+3, V1+5 has,On the other hand, a small secondary bypass line Ik, Ik+1, Ik+2 equipped with a valve typically of relatively smaller diameter: Vi+1, Vi+3, V1+5.

[0084] Each plate is also connected to a secondary bypass line Mk or Mk+1 or Mk+2, equipped with a valve of relatively smaller diameter VMk or VMk+1 or VMk+2.

[0085] In total, for each 2-plate section, there are 4 network valves of relatively larger diameter, two plate valves, also of relatively larger diameter to allow circulation with their nominal flow rate of F, D, R, E,.. and two valves of relatively smaller diameter in bypass (attached and secondary), that is 8 valves, and therefore on average 4 valves per plate of which 3 valves of larger diameter. Therefore, a larger diameter valve is gained per plate when comparing this device with that in Figure 1, according to Petition 870180010737, dated 07 / 02 / 2018.pg. 25 / 43 23 / 28 previous technique.

[0086] The device works as follows:

[0087] For section Sk, for example, when it is desired, in a given period, to feed or stretch one of the fluids F, D, R, E onto the plate Pj, the corresponding network valve VFK, VDK, VRk or VEK is opened, as well as the plate valve Vi. The other network valves in section Sk are then closed, as well as Vi+1, the secondary bypass valve VMk of the upper secondary bypass line Mk and the smaller attached bypass valve Vi+1. Conversely, the smaller secondary bypass valve VMk+1 of the secondary bypass line Mk+1 is preferentially opened.

[0088] When it is desired, at another time, to feed or stretch one of the fluids F, D, R, E on plate Pi+1, the corresponding network valve VFK, VDK, VRK or VEK is opened, as well as the plate valve Vi+1. The other network valves in section Sk are then closed.as well as Vi. The smaller bypass valve attached Vi+1 may remain closed. The smaller secondary bypass valve VMk of the upper secondary bypass line Mk is preferably opened, and the smaller secondary bypass valve VMk+1 of the secondary bypass line Mk+1 is obligatorily closed.

[0089] When it is desired, in a third period, not to feed or draw one of the fluids F, D, R, E into the plates Pi and Pi+1, the network valves VFK, VDK, VRK and VEK are closed. A limited flow rate is then circulated in the line Lk (drawn from Pi and injected Pi+1) by opening Vi, closing Vi+1 and opening the smaller bypass valve attached Vi+1. A small flow rate can thus be ensured via Ik. Vi+1 is typically a regulating valve (with progressive opening) controlled by flow regulation from a flow meter not shown.

[0090] When it is desired, during a fourth period, 1st) not Petition 870180010737, of 07 / 02 / 2018, p. 26 / 43 24 / 28 alimony,Neither stretching one of the fluids F, D, R, E on plates P, and Pi+1, closes the network valves VFK, Vdk, VRK, and VEK. And 2) having a zero diversion flow in line Lk, V,, Vi+1, and the smaller diverting valve attached to Vi+1 are closed. A limited flow circulation then takes place in the secondary diversion line Mk and possibly in Mk+1, except when plates Pi-1 or Pi+2 are in the feeding or stretching phase, in which case the corresponding secondary diversion line must remain out of service.

[0091] The other sectors Sk+1, Sk+2 operate analogously.

[0092] An exemplary type of operation of a Sk sector is, for example, the following, in which the valves for Sk operation that are open are mentioned, the valves not mentioned being closed: only the secondary bypass circulations in Mk, for the P sweep, are described (not those in Mk+1).

[0093] Period 1: Bypass sweep of P, for Pi+1. open valves: V,,Period 2: Desorbent injection at P,. Valves open: Vi+1 Vdk

[0095] Period 3: Desorbent injection at Pi+1. Valves open: Vi+1, Vdk. And bypass sweep from P, to P,. Valve open: V,, Vmk

[0096] Period 4: Bypass sweep from P, to Pi+1. Valves open: V,, Vi+1

[0097] Period 5: Raffinate stretching from P,. Valves open: Vi, Vrk

[0098] Period 6: Raffinate stretching from Pi+1. Valves open: Vi+1, Vrk. And bypass sweep from P, to P,. Valve open: VMk.

[0099] Period 7: Bypass sweep from P, to Pi+1. Open valves: V,, Vi+1 [ooioo] Period 8: Sweep in deviation from Pi-1 to P,. Open valve: VMK.

[00101] Period 9: Sweep in deviation from P, to Pi+1. Open valves: V,, Vi+1

[00102] Period 10: Sweep in deviation from Pi-1 to P,. Open valve: VMK.

[00103] Period 11: Sweep in deviation from P, to Pi+1. Open valves: V,,Vi+1

[00104] Period 12: Load injection at P,. Valves open: V,, Vfk

[00105] Period 13: Load injection at Pi+1. Valves open: Vi+1, VFK. And bypass sweep from Pi-1 to P,. Valve open: VMK.

[00106] Period 14: Bypass sweep from P, to Pi+1. Valves open: V,, Vi+1

[00107] Period 15: Bypass sweep from Pi-1 to P,. Valve open: VMK

[00108] Period 16: Bypass sweep from P, to Pi+1. Valves open: V,, Vi+1

[00109] Period 17: Bypass sweep from Pi-1 to P,. Valve open: VMK

[00110] Period 18: Bypass sweep from P, to Pi+1. Open valves: V,, Vi+1

[00111] Period 19: Sweep from Pi-1 to P,. Open valve: VMK

[00112] Period 20: Sweep from P, to Pi+1. Open valves: V,, Vi+1

[00113] Period 21: Extract stretch of P,. Open valves: Vi, VEK

[00114] Period 22: Extract stretch of Pi+1. Open valves: Vi+1, VEK. And sweep from Pi-1 to P,. valve open: VMK

[00115] Period 23: Bypass sweep from P, to Pi+1. valves Petition 870180010737, dated 07 / 02 / 2018, page 28 / 43 26 / 28 open: V,, Vi+1

[00116] Period 24: Bypass sweep from Pi-1 to P,. valve open: VMK

[00117] The principles that allow establishing the preferred sequence are as follows: 1) each time one of the main fluids (F, D, R, E) is withdrawn or injected through a network valve in a bypass line Lk, this network valve remains open twice in succession (when 2 successive periods). The first time, the upper plate valve, when open, allows connection to the upper plate P, and the lower plate valve Vi+1, as well as the smaller valve Vi+1, for diverting fluid control attached to line Ik, are closed. The second time, the lower plate valve Vi+1, when open, allows connection to the lower plate Pi+1, and the upper plate valve V, and the smaller diverting fluid control valve Vi+1,are closed. In addition, the smaller control valve VMK of the upper secondary bypass line Mk is opened to connect the plates Pi-1 (not shown) of section Sk-1 (not shown) and the plate P of section Sk; 2) outside the injection or stretching periods of the main fluids (F, D, R, E), a bypass flow is alternately circulated once in two in a row in Lk. The upper plate valve V is then opened, the lower valve Vi+1 is closed, and the smaller control valve Vi+1, located in an adjacent bypass around Vi+1, regulates the bypass flow via the adjacent bypass Ik. Alternately, a bypass flow circulates in the upper secondary bypass line Mk regulated by the smaller control valve VMK, with the two plate valves Vi-1 and V closed, to create a bypass between Pi-1 and P. This latter flow rate would not, however, be put into service if plate Pi-1 were fed or stretched by F, D, R, E,...

[00118] Figure 3 represents a column section of an SMB, Petition 870180010737, dated 07 / 02 / 2018, page 29 / 43 27 / 28 according to another embodiment of the invention. The disc valves (not numbered) do not include a smaller attached bypass line Ik to limit the bypass sweep flow at Lk, as for the device in Figure 2. This function is ensured by a typically progressive opening valve: 9A for Lk, and 9B for Lk+1. This allows for the non-use of attached lines Ik, Ik, but requires relatively larger diameter valves 9A, 9B to avoid limiting the circulating flow at Lk.

[00119] Alternatively, an Lk plate valve may be used as a flow control valve, in place of the valve (ae) or valve 9B. This valve or valves must then have a driven seal. Best Embodiment:

[00120] The best embodiment of the invention is an SMB, whose column(s) is / are essentially made up of Sk sections with smaller Vi+1 valves,...in bypass attachments of the Pi+1 plates..., according to figure 2.

[00121] In this device, there are 3 larger diameter valves per plate (6 per Sk sector: VFK, VDK, VRK, VEK, Vi, Vi+1), compared to 4 in the previous technique (according to figure 1). There is on average one smaller regulating valve per plate (VMK, or Vi+1, for the 2 Sk plates) compared to 0.5 in the previous technique, but this valve is much less expensive, and the total number of valves is reduced (4 compared to 4.5).

[00122] The device, according to the invention, thus described can be used for any chromatographic separation process, notably for the separation of an aromatic hydrocarbon from a load of aromatics having essentially 8 carbon atoms and comprising this hydrocarbon.

[00123] In particular, it can be used for the separation of paraxylene from an aromatic shear essentially composed of C8 hydrocarbons, using toluene or diethylbenzene as per Petition 870180010737,From 07 / 02 / 2018, page 30 / 43 28 / 28 desorbent and a zeolite as adsorbent, as described, for example, in patent FR 2,789,914. It can also be used for the separation of metaxylene from an aromatic cut at C8, using toluene and tetralin as desorbent and an adsorbent, as described, for example, in US patent 5,900,523 and in patent applications FR 05 / 52,485 and FR 05 / 52,486.

[00124] It can also be used for the separation of one or more normal paraffins (separated from the rest of the hydrocarbons) from a mixture of hydrocarbons, notably paraffinic or paraffinic and naphthenic, for example, using normal butane or normal pentane as a desorbent (possibly isooctane as an inert diluent) and a zeolite 5A as an adsorbent.

[00125] Finally, it can be used for the separation of at least one olefin from a hydrocarbon cut, this hydrocarbon comprising, according to known conditions of the prior art, for example,using a calcium-exchanged zeolite X.

[00126] The invention is not limited to the preceding description, and the skilled person may use for its application any other technical feature known in the state of the art. Petition 870180010737, dated 07 / 02 / 2018, page 31 / 43 1 / 7,

Claims

CLAIMS 1. A device that allows the separation of at least one compound from a mixture comprising that compound by adsorption on a simulated moving layer, characterized in that it comprises: - at least one column comprising a plurality of adsorbent layers Ai separated by distributor / extractor plates Pi for the sequential feeding and extraction of at least two feed fluids: a feed F and a desorbent D, and at least two stretching fluids: a raffinate R and an extract E, Pi being disposed between layer Ai and the immediately lower layer Ai+1; - the device also comprising at least one feed F-Net, one desorbent D-Net, one raffinate R-Net and one extract E-Net, each of these networks being connected to the column by a plurality of lines comprising 2-way controlled shut-off valves with an opening diameter greater than or equal to a value α, referred to as network valves,for the sequential feeding or stretching of these feed or stretching fluids; in which the column is divided, over most of its height at least, into a plurality of adjacent superimposed sections Sk, each section Sk being essentially constituted by 2 successive adsorbent layers Ai, Ai+1 and by the 2 distributor / extractor plates Pi, Pi+1 which are arranged respectively immediately below Ai and Ai+1, each of the distributor / extractor plates Pb Pi+1 of each of the Sk sections being of a single common network for the sequential feeding and stretching of F, D, R, E, the Pi, Pi+1 plates of each section Petition 870180010737, of 07 / 02 / 2018, page. 32 / 43 2 / 7 Sk are linked together by a main external bypass line Lk connected to each of the Pb Pi+1 plates of Sk by a ferrule comprising a unique 2-way controlled disconnecting valve specific to that Pi plate.Pi+1, designated as a Vi or Vi+1 plate valve, with an opening diameter greater than or equal to the value α for the sequential feeding or stretching of these feed or stretching fluids into or from Pi, each of these Lk bypass lines comprising at least one controlled means of limiting the flow circulating in Lk that is either installed on the Lk line, or bypassed around a Vi or Vi+1 plate valve of a Sk plate, in which the Lk bypass line of each of the Sk sections is connected to each of the F-Net, D-Net, R-Net, E-Net networks via a single line with an internal diameter greater than or equal to α, comprising a single network valve, respectively VFk, VDk, VRk, VEk, which has an opening diameter greater than or equal to α, for the sequential feeding or stretching of the corresponding F, D, R, or E fluid into or from the Sk section considered, the device also comprising a plurality of lines secondary external deviations Mk,Each of the Mk lines connecting the 2 adjacent sectors Sk-1 and Sk via 2 connection points; the first connection point being disposed on the tip connected to the lower plate Pi-1 of the upper sector Sk-1 between Pi-1 and the plate valve Vi-1, the second connection point being disposed on the tip connected to the upper plate Pi of the lower sector Sk between Pi and the plate valve Vi, each of the secondary external bypass lines Mk comprising a 2-way controlled valve VMk with an internal opening diameter less than or equal to a value β, with β < 0.6 α. Petition 870180010737, dated 07 / 02 / 2018, page 33 / 43 3 / 7 2. Device, according to claim 1, characterized in that 30 mm < 1.7 x β < α < 600 mm.

3. Device, according to either of claims 1 and 2, characterized in that the bypass line Lk has an internal diameter at least equal to the largest opening diameter of the network valves connected to Lk.

4. Device,According to any one of claims 1 to 3, characterized in that the entire column, except for the head plate, is constituted by these adjacent superimposed sections Sk, the column comprising a lower outlet line assimilated to a plate Pn corresponding to the lower adsorbent layer An.

5. Device, according to any one of claims 1 to 4, characterized in that each of these main bypass lines Lk comprises at least one controlled means for limiting the flow circulating Lk, which is installed in an attached bypass around a plate valve Vi, or Vi+1 of a plate Sk.

6. Device, according to claim 5, characterized in that this means for limiting the flow circulating Lk installed in an attached bypass around this plate valve Vi, or Vi+1 comprises a controlled valve with an opening diameter less than or equal to β.

7. Device, according to any one of claims 1 to 6,characterized in that each of these secondary diversion lines Mk comprises at least one controlled means of limiting the flow circulating in Mk, this means comprising such valve VMK.

8. Device, according to any of claims 1 to 7, characterized in that it comprises a sequential feed network RE-Net of a reflux fluid RE comprising Petition 870180010737, dated 07 / 02 / 2018, page 34 / 43 4 / 7 mainly extract, this network being connected to each of the sectors Sk via a single line of internal diameter greater than or equal to α comprising a single network valve VREK, which is of opening diameter greater than or equal to α.

9. Device, according to any one of claims 1 to 8, characterized in that it comprises a sequential stretching network R2-Net of a refined second R2, this network being connected to each of the Sk sectors via a single line of internal diameter greater than or equal to alpha,comprising a single network valve VR2K, which has an opening diameter greater than or equal to α.

10. A process for separating a product using a device, as defined in any one of claims 1 to 9, characterized in that, during a cycle: - each of the Lk lines is sequentially used for circulation with its nominal flow rate of F, D, R, E, to or from each of the Sk plates via the corresponding plate valve and the corresponding network valve in series; - a sweep is performed with a flow rate lower than that of the nominal flow rates of fluids F, D, R, E, of each of the main external bypass lines Lk during at least part of the time in which no network valve connected to Lk is opened, by an internal stream from one plate of the device and recycled towards another plate of the device, and any internal sweep of Lk is stopped,when a network valve connected to Lk is opened; - a sweep is performed with a flow rate lower than that of the nominal flow rates of fluids F, D, R, E of each of the secondary external bypass lines Mk for at least part of the time, by an internal stream originating from one plate of the device and recycled towards another plate of the device.

11. Process, according to claim 10, characterized by Petition 870180010737, dated 07 / 02 / 2018, page. 35 / 43 5 / 7 characterized by the fact that the Lk sweep is performed by circulating a stream originating from the upper plate Pi of Sk, recycled to the lower plate Pi+1 of Sk.

12. Process, according to any one of claims 10 and 11, characterized by the fact that the Mk sweep is performed by circulating a stream originating from the lower plate Pi-1 of Sk-1, recycled to the upper plate Pi of Sk.

13. Process, according to any one of claims 10 to 12,characterized in that an internal sweep of Lk is performed from the upper plate Pi of Sk to the lower plate Pi+1 of Sk, at any time or Sk is not connected to one of these sequential feed or sequential stretching fluid networks and is located immediately before a period or one of the network valves connected to Sk is opened for the feeding or stretching of one of these fluids to or from the upper plate Pi.

14. Process, according to any one of claims 10 to 13, characterized in that for each of the diverter lines Lk, a sweep of Lk is performed, at any time during which no network valve connected to Lk is open.

15. Process, according to any one of claims 10 to 14, characterized in that the plate valves Vi-1, and Vi of the tips connected by a secondary external diverter line Mk are closed, when a sweep of Mk is performed.

16. Process,According to any one of claims 10 to 15, characterized in that a sweep of Mk is performed at any point during which the plate valves Vi-1 and Vi, of the tips connected by a secondary external bypass line Mk, are closed.

17. Process, according to any one of claims 10 to 16, characterized in that Lk is used by each of the fluids F, D, R, E over their entire length during a cycle.

18. Process, according to any one of claims 10 to 17, characterized in that asynchronous permutations of the feed and stretch points of fluids F, D, R, E are performed in the column.

19. Process according to claim 18, characterized in that the device uses chromatographic zones, some of which at least are equivalent to a non-integer number of adsorbent layers.

20. Process,20. Process according to any one of claims 10 to 19, characterized in that it is for the separation of an aromatic hydrocarbon from a charge of aromatics having essentially 8 carbon atoms and comprising that hydrocarbon.

21. Process according to claim 20, characterized in that it is for the separation of paraxylene from a charge of aromatic hydrocarbons having essentially 8 carbon atoms.

22. Process according to claim 20, characterized in that it is for the separation of metaxylene from a charge of aromatic hydrocarbons having essentially 8 carbon atoms.

23. Process according to any one of claims 10 to 19, characterized in that it is for the separation of at least one normal paraffinic hydrocarbon from a charge of hydrocarbons comprising that hydrocarbon.

24. Process according to any one of claims 10 to 19,characterized by the fact that it is a separation of at least one olefinic hydrocarbon, from a hydrocarbon charge. Petition 870180010737, dated 07 / 02 / 2018, page 37 / 43 7 / 7, comprising this hydrocarbon. Petition 870180010737, dated 07 / 02 / 2018, page 38 / 43 1 / 3 Pi Pi + 1 Pi + 2 Pi + 3 Pi + 4 Pi + 5 FIG 1 ZOId 3 / 3 FIG 3,