Simulated moving bed separation device and method with extended jet breaker

Abstract

To improve a flow of fluids inside a column having a plurality of adsorbent beds disposed in series in a direction of the flow of the fluids.SOLUTION: A distribution / collection panel 3 includes an upper screen 4, a collector 5, a separation plate 6 with outlet openings 11, a distributor 7, a lower screen 8, an injection / withdrawal tank 9 adjacent to the separation plate 6, and a jet breaker element 12 perpendicular to a flow (E) of main fluid, and further includes solid jet breaker plates 13 that are: extended on respective side of the injection / withdrawal tank 9; juxtaposed with the lower screen 8; disposed beneath the outlet openings 11; designed to direct the main fluid in the distributor 7 in a direction orthogonal to the direction of the flow (E), a ratio I / L of a width I of the solid jet breaker plate 13 to a width L of a lateral part of the separation plate 6 being at least 0.1.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to the field of separation of natural or chemical products that are difficult to separate by distillation. And a series of methods and related apparatuses known as simulated moving bed separation methods or apparatuses using either pseudo-countercurrent or pseudo-cocurrent are utilized (hereinafter referred to as "SMB").

[0002] The related fields are, in particular, the separation of paraxylene from other C8 aromatic isomers. Other related fields are not particularly limited, but on the one hand, separating normal paraffins from branched paraffins, naphthenes and aromatics on the other hand, olefin / paraffin separation, separating metaxylene from other C8 aromatic isomers, and separating ethylbenzene from other C8 aromatic isomers.

[0003] Specifically, the present invention relates to an SMB apparatus and method including an apparatus for distributing and collecting fluids in a column in which a fluid flow is carried out in a solid particle medium called an adsorbent bed or granular medium.

[0004] The column means a column including a plurality of adsorbent beds arranged in series in the direction of one or more fluid flows carried out in the column. The fluid passing continuously through the adsorbent beds is called the main fluid and is distinguished from other secondary fluids that can be added to the main fluid through a distribution and collection device, also called a plate, generally located between two consecutive beds.

[0005] The plate is composed of at least one collection zone and a valve system that enables collection of the main fluid and / or injection of secondary fluids and mixing of these secondary fluids with the main fluid. The plate also includes at least one distribution zone, and the purpose of the distribution zone is to distribute the fluid resulting from the mixing of the main fluid and the secondary fluids onto the granular bed located immediately downstream in the direction of the main fluid flow. In the following description, the description of the "downstream" bed shall indicate the granular bed located immediately downstream of the distributor according to the present invention. The present invention relates to a distribution zone (hereinafter referred to as a distributor) that enables each granular bed, or at least a portion thereof, to be equipped with a collection zone or a preceding granular bed, i.e., an "upstream" bed, to supply a fluid in the form of a jet coming from a system for mixing a main fluid and a secondary fluid in the direction of the main fluid flow. [Background technology]

[0006] Numerous devices are known for distributing, mixing, or collecting fluids in chambers containing solid particles, such as in multi-stage columns. Plates generally serve to distribute the fluid as homogeneously as possible across the cross-section of the column, to effectively mix the main fluid passing through the various beds of the column with one or more secondary fluids introduced into each bed, to collect the fluid flow between any two beds, and finally, to best homogenize the concentration at the bed outlet before the solid particles enter the next bed, i.e., the bed located immediately downstream of the device.

[0007] Furthermore, the plate must satisfy several constraints, such as minimizing axial dispersion, minimizing pressure loss, and avoiding the generation of hydrodynamic turbulence that would adversely affect the performance of the method.

[0008] The plate has several features that are well known to those skilled in the art.

[0009] To clarify the text, the column is divided into multiple plates Pi and adsorbent beds Ai, with plates Pi positioned immediately upstream of adsorbent beds Ai in the direction of the main fluid flow. Furthermore, adsorbent bed Ai+1 is referred to as the next adsorbent bed located downstream of adsorbent bed Ai in the direction of the main fluid flow. Similarly, plate Pi+1 indicates a subsequent plate located downstream of plate Pi in the direction of the main fluid flow.

[0010] Furthermore, each plate Pi in the column may have multiple collection / injection valve systems and multiple distributors, depending on how the plate may be divided into multiple sectors or regions called panels. Generally, each panel of the plate has one collection / injection valve system and one distributor.

[0011] Each panel can have various shapes, the most common being a division into angled sectors or meridian panels of substantially the same width, i.e., parallel panels.

[0012] Each panel of the Plate Pi allows for the following: - The main fluid is collected from the adsorbent bed Ai-1 via a system called a collection baffle. - The main fluid is extracted from the adsorbent bed Ai-1, or the main fluid leaving the adsorbent bed Ai-1 is mixed with a secondary fluid optionally injected into the panel via a distribution network terminating in an injection / extraction tank. - The main fluid, collected either alone or as a mixture with a secondary fluid, is redistributed via a distributor across the next adsorbent bed Ai.

[0013] European Patent Application Publication No. 0074815, U.S. Patent Application Publication No. 2006 / 0108274, and French Patent Invention No. 270480 provide examples of plates used in SMB adsorption.

[0014] In some cases, the particle bed may be blocked by the distributor, meaning there may be no open space between the distributor and the adsorbent bed Ai.

[0015] As described in U.S. Patent Application Publication 2006 / 0108274, when there is an open space between the distributor and the floor, the distributor can be designed to avoid generating locally excessive fluid velocity at the floor inlet in order to prevent partial fluidization of the particle floor, which can adversely affect the performance of the method. Specifically, U.S.2006 / 0108274A1 describes a jet-breaking plate positioned above the distributor and below an open zone corresponding to the outlet for the liquid jet, in order to limit the high velocity of this jet at the inlet of the downstream granular floor. In contrast, the distributor described in U.S. Patent Application Publication 2006 / 0108274 may not be sufficient to eliminate partial fluidization of the particle floor, and therefore other solutions may be necessary.

[0016] To further reduce the partial fluidization of the particle bed, prior art has proposed several types of solutions, including the following: - To limit turbulence and high velocity at the particle bed inlet, a screen or perforated plate type element is placed downstream of the distributor. - Increase the number of panels and the openings of the collection baffles to reduce the speed at which the fluid passes through the distribution / mixing device.

[0017] U.S. Patent Application Publication No. 2009 / 0321359 proposes a distributor consisting of the following three elements arranged from top to bottom in the direction of fluid flow: - A solid jet shredder positioned substantially along the axis of the outlet opening of the panel's collection baffle, centered on the axis of the collection baffle. - An intermediate perforated plate extending laterally beyond the jet breaker, with a width between the width of the jet breaker and a higher value equal to half the width of the panel, within plus or minus 5 cm, and with an opening between 15% and 30%, and - A distribution board that extends across the entire area of ​​the panel P and has an opening ratio of 7% to 15%. [Prior art documents] [Patent Documents]

[0018] [Patent Document 1] European Patent Application Publication No. 0074815 [Patent Document 2] US Patent Application Publication No. 2006 / 0108274 [Patent Document 3] French Patent Invention No. 270480 [Patent Document 4] US Patent Application Publication No. 2009 / 0321359 [Summary of the Invention] [Problems to be Solved by the Invention]

[0019] However, the hydrodynamics of the fluid inside the adsorbent bed can be improved.

[0020] The problem to be solved by the present invention is to improve the flow of fluid inside a column having a plurality of adsorbent beds arranged in series in the direction of fluid flow. [Means for Solving the Problems]

[0021] The present invention relates to a distribution and collection device (hereinafter also referred to as a panel) that enables the recovery of the main fluid (fluid circulating inside the column) from the upstream adsorbent bed and the supply of the main fluid to the downstream adsorbent bed. Advantageously, the distribution and collection device also has a system for mixing the main fluid with one or more secondary fluids.

[0022] According to a first aspect, the present invention can be defined as a device for distributing and collecting the main fluid, the device being designed to supply the downstream adsorbent bed of a simulated moving bed separation column, the device including at least one panel, the panel including, in the direction of the flow of the main fluid, the following. - An upper screen adapted to support the bed of solid particles of the upstream adsorbent bed, - A collector (or collection zone) adapted to collect the main fluid leaving the upstream adsorbent bed, - A separation plate including at least one outlet opening for separating the collector from the distributor and for directing the mainstream body from the collector towards the distributor (or distribution zone), - A distributor capable of distributing the main body across downstream adsorbent beds, and - Lower screen.

[0023] The aforementioned panel further, - An injection / extraction tank adjacent to the separation plate and positioned substantially in the center of the panel, wherein the separation plate includes two sides located on either side of the injection / extraction tank, each side extending over a width L from the injection / extraction tank to the side wall of the panel, - Includes a jet fragmentation element extending perpendicular to the direction of flow of the main fluid, The jet fracturing element includes two solid jet fracturing plates, and the jet fracturing element plates are, - Extending on both sides of the injection / extraction tank, - Placed alongside the lower screen, - Located below at least one exit opening, - The main body within the distributor is oriented in a direction perpendicular to the direction of the flow of the main fluid. In this apparatus, the ratio l / L of the width l of each solid jet fragmentation plate to the width L of the side of the separation plate is at least 0.1.

[0024] Advantageously, the jet fracturing element makes the following possible in particular: - Improve the flow by reducing the axial dispersion of the fluid passing through the downstream adsorbent bed (closest to plug flow), - To improve the hydrodynamics of the fluid in the downstream adsorbent bed, and, - To reduce the formation of grooves on the upper surface of the downstream adsorbent bed.

[0025] According to one or more embodiments, the jet fracturing element is located below the injection / extraction tank and includes a central body connecting two solid jet fracturing plates.

[0026] According to one or more embodiments, the ratio l / L of the width l of the solid jet fracturing plate to the width L of the side of the separation plate is at least 0.2, preferably at least 0.25.

[0027] According to one or more embodiments, the ratio l / L of the width l of the solid jet fracturing plate to the width L of the side of the separation plate is between 0.1 and 0.7, preferably between 0.2 and 0.4, and more preferably between 0.25 and 0.30.

[0028] According to one or more embodiments, a jet fracturing element and an injection / extraction tank are arranged side by side.

[0029] According to one or more embodiments, the distance between the lower end of the separation plate and the upper end of the jet fracturing element is less than 10% of the panel width, preferably less than 6%.

[0030] According to one or more embodiments, the separation plate has an opening between 1% and 10%, preferably between 4% and 8%.

[0031] According to one or more embodiments, the separation plate is perforated with holes having a diameter of 5 mm to 50 mm and / or a center-to-center distance of 30 mm to 90 mm.

[0032] According to a second aspect, the present invention can be defined as a distribution and collection plate for a pseudo-moving bed separation column, comprising a plurality of devices according to the first aspect.

[0033] According to a third aspect, the present invention can be defined as a pseudo-mobile bed separation column comprising a plurality of plates according to the second aspect.

[0034] According to one or more embodiments, the column is divided into N adsorbent beds separated by n plates, where the number of adsorbent beds N and the number of plates n are the same, and are 4 to 24, preferably 8 to 19, and more preferably 12 to 15.

[0035] According to a fourth aspect, the present invention can be defined as a pseudo-moving bed separation unit comprising at least one column according to the third aspect.

[0036] According to a fifth aspect, the present invention can be defined as a pseudo-moving bed separation method comprising the steps of supplying at least one raw material and desorbent to at least one column, and withdrawing at least one extract and at least one raffinate from the column, wherein the column comprises one or more beds of adsorbent solids interconnected in a closed circuit and separated by plates comprising a plurality of devices according to the first aspect, wherein the supply and withdrawal points on the plates of the column are shifted over time by a value corresponding to one adsorbent bed with a switching time, and the column comprises a plurality of operating zones, in particular the following main zones defined and indicated by number: - Zone I for desorption of the product to be separated, between the injection of the desorbing agent and the withdrawal of the extract. - Zone II, located between the extraction of the extract and the injection of the raw materials, for the desorption of isomers of the products to be separated. - Zone III, located between the injection of raw materials and the extraction of raffinate, for the adsorption of products to be separated, and - Zone IV, between the removal of raffinate and the injection of the desorbent. We decided, In this method, the adsorbent bed is distributed to zones I to IV according to the a / b / c / d type configuration, that is, the distribution of the bed is as follows: - Number of floors in Zone I, a - Number of floors in Zone II: b, - The number of floors in Zone III, c, and - Number of floors in Zone IV, d It is said that, In this method, - a=(t*0.2)*(1±0.2), - b=(t*0.4)*(1±0.2), - c=(t*0.27)*(1±0.2), and, - d=(t*0.13)*(1±0.2), or, - a=(t*0.17)*(1±0.2), - b=(t*0.42)*(1±0.2), - c=(t*0.25)*(1±0.2), and, - d=(t*0.17)*(1±0.2) It is said that, In this method, t is a natural integer between 6 and 24, preferably between 8 and 19, and more preferably between 12 and 15.

[0037] According to one or more embodiments, - The raw materials include a mixture of aromatics containing eight carbon atoms, and / or, - The desorbing agent is selected from the group consisting of one or more isomers of diethylbenzene and toluene, preferably the desorbing agent is paradiethylbenzene or toluene, more preferably the desorbing agent is toluene, and / or - The adsorbent used contains or consists of faujasite selected from the group consisting of BaX, BaKX, and BaLSX.

[0038] According to one or more embodiments, - The temperature inside the adsorbent bed is between 140°C and 189°C, preferably between 155°C and 185°C, more preferably between 170°C and 180°C, and / or - The pressure within the adsorbent bed is between 1 MPa and 10 MPa, preferably between 2 MPa and 4 MPa, more preferably between 2 MPa and 3 MPa, and / or - The switching time is between 30 seconds and 100 seconds, preferably between 40 seconds and 80 seconds, and / or - The surface velocity between the floors is between 0.2 cm / s and 2.5 cm / s, preferably between 0.5 cm / s and 2 cm / s.

[0039] Other features and advantages of the present invention in the embodiments described above will become apparent from reading the following description and non-limiting exemplary embodiments with reference to the accompanying figures described below. [Brief explanation of the drawing]

[0040] [Figure 1] Figure 1 is a partial cross-sectional view of a multi-stage column having three consecutive plates, each plate showing multiple panels with a collection system, a mainstream extraction or secondary fluid injection system, and a standard distributor. [Figure 2] Figure 2 is a partial cross-sectional view of a multi-stage column having three consecutive plates, each plate having multiple panels equipped with a collection system, a mainstream extraction or secondary fluid injection system, and a distributor according to the present invention. [Modes for carrying out the invention]

[0041] Next, embodiments of the apparatus and method according to the above-described aspects will be described in detail. In the following detailed description, numerous specific details are disclosed in order to provide a deeper understanding of the apparatus and method. However, it will be obvious to those skilled in the art that the apparatus and method can be carried out without these specific details, and in other cases, well-known features are not described in detail in order to avoid unnecessarily complicating the description.

[0042] In this application, the term “equipped with” is synonymous with “include” and “contain,” and is inclusive or open, not excluding other elements not described. Furthermore, the term “equipped with” is understood to include the exclusive and closed term “to constitute.” In addition, in this specification, the terms “essentially” or “substantially” correspond to an approximation of ±10%, preferably ±5%, and more preferably ±2%. For example, an element substantially positioned at a location on a panel may be positioned on the panel with respect to the panel’s width or height with respect to an approximation of ±10%, preferably ±5%.

[0043] According to a first aspect, the present invention can be defined as a distribution and collection device (hereinafter also referred to as a panel) for an SMB separation unit, the distribution and collection device is configured to collect fluid coming from an upstream adsorption bed and distribute the fluid toward a downstream adsorption bed.

[0044] The SMB separation unit consists of at least one separation column divided into N adsorbent beds separated by n plates (defining inter-bed zones), and each plate itself can be divided into multiple panels. Preferably, the number of adsorbent beds N and the number of plates n are the same, between 4 and 24, preferably between 8 and 19, and very preferably between 12 and 15.

[0045] Dividing a plate Pi into panels is known from the prior art. The two most common types of division are division into meridian panels and division into panels corresponding to angled sectors. Meridian panels correspond to the division of plate Pi into elements that are parallel and continuous to each other, so as to ensure complete coverage of the horizontal cross-section of the plate. Meridian panels are oriented according to the diameter of the plate and preferably have substantially the same width. According to one or more embodiments, each plate is divided into 4 to 24 panels, preferably 12 to 16 panels. The panels are preferably meridian panels. [About this device] Generally, the distribution and collection device is positioned in the direction of the main fluid flow. - A collector designed to collect the main body flowing out from the upstream adsorption bed, - An injection / extraction tank configured to extract the collected mainstream or to inject a secondary fluid into the mainstream so that the secondary fluid can be mixed with the mainstream, - A distributor designed to distribute the main body collected either alone or as a mixture with a secondary fluid across the downstream adsorption bed.

[0046] Referring to Figures 1 and 2, column 1 comprises a plurality of solid particle beds 2 arranged in series in the flow direction E of the main fluid carried out within column 1. Specifically, column 1 has a plate Pi-1, an adsorbent bed Ai-1 (referred to as the upstream adsorbent bed Ai-1), a plate Pi, an adsorbent bed Ai (referred to as the downstream adsorbent bed Ai), and a plate Pi+1 in the flow direction E of the main fluid.

[0047] Referring to Figures 1 and 2, the plate Pi is divided into a plurality of panels 3, each panel 3 preferably having vertical walls including two side walls 10, and each panel 3 also in the direction of the main fluid flow E, - An upper screen 4 that allows the floor of solid particles 2 to be supported, or other equivalent device (e.g., a perforated plate), - A collector 5 or collection zone (shown as collection channel C in the diagram) is configured to collect the main body leaving the upstream adsorbent bed Ai-1, - Separation plate 6 that separates the collector 5 from the distributor 7, - A distributor 7 or distribution zone (shown as a distribution channel D in the drawing) is provided to distribute the main body collected either alone or as a mixture with a secondary fluid across the downstream adsorbent bed Ai, - A lower screen 8 that enables support for panel 3, or other equivalent device (e.g., a perforated plate), - The upper screen 4, collector 5, separation plate 6, distributor 7, and lower screen 8 extend from one side wall 10 to the other side wall 10.

[0048] Referring to Figures 1 and 2, panel 3 also includes an injection / extraction tank 9 configured to extract the main fluid collected by the collector 5, or to inject a secondary fluid to mix with the main fluid. The injection / extraction tank 9 is adjacent to the separation plate 6 and is positioned substantially along the center of panel 3, i.e., along the central axis Z of panel 3 (as shown in the cross-sectional views of Figures 1 and 2). The central axis Z of panel 3 is the transverse axis of panel 3, i.e., parallel to the direction of flow E, and perpendicular to the plane formed by the separation plate 6.

[0049] Advantageously, the upper screen 4 and separation plate 6 together form a collector 5 (collection zone) designed to direct the main body toward the injection / extraction tank 9.

[0050] Advantageously, the separation plate 6 has two sides located on either side of the injection / extraction tank 9, i.e., the injection / extraction tank 9 separates the separation plate 6 into two sides, each side extending over a width L from the injection / extraction tank 9 to the side wall 10 of the panel 9. The width of the panel is equal to the distance between the two side walls 10, i.e., the width of the panel is equal to the width of the injection / extraction tank 9 plus the sum of the widths L of the two sides located on either side of the injection / extraction tank 9.

[0051] In the detailed description, well-known features of the injection / extraction tank 9 are not described in detail in order to avoid unnecessarily complicating the explanation. For example, referring to Figures 1 and 2, the injection / extraction tank 9 extends substantially from the upper screen 4 to the lower screen 8, but it will be apparent to those skilled in the art that the injection / extraction tank 9 may extend substantially from the upper screen 4 to the separation plate 6, or from the separation plate 6 to the lower screen 8.

[0052] It is also understood that the injection / extraction tank 9 can be positioned between the collector 5 and the separation plate 6, or between the separation plate 6 and the distributor 7, or between the collector 5 and the distributor 7.

[0053] Advantageously, the separation plate 6 is provided with at least one, preferably at least two, outlet openings 11, preferably located near the injection / extraction tank 9, and configured to deliver the main fluid from the collector 5 toward the distributor 7. Preferably, at least one outlet opening 11 is located on either side of the injection / extraction tank 9. Depending on the operating mode of panel 3, the main body is collected in the injection / extraction tank 9 or mixed with the secondary fluid exiting the injection / extraction tank 9. The thus mixed main and secondary fluids are redistributed toward the downstream adsorbent bed Ai by passing through the distributor 7. According to one or more embodiments, the term "nearby" corresponds to a distance of less than 10%, preferably less than 5%, of the width L of the side of the separation plate 6.

[0054] Advantageously, the lower screen 8 and separation plate 6 together form a distributor 7 (distribution zone) for directing the main body collected as a single main fluid or a mixture with a secondary fluid toward the downstream adsorbent bed Ai.

[0055] Referring to Figures 1 and 2, panel 3 also includes a jet fragmentation element 12 that extends perpendicular to the direction of the main fluid flow E and is positioned below at least one outlet opening 11. Advantageously, the jet fragmentation element 12 is configured to guide the main body, either alone or as a mixture with a secondary fluid, in a direction perpendicular to the direction of the main fluid flow E within the distributor 7, i.e., toward the side wall 10 of panel 3.

[0056] Advantageously, the jet fracturing element 12 and the lower screen 8 are adjacent to each other in the sense that they are placed side by side (e.g., screwed, welded, riveted, glued to each other, etc.).

[0057] Advantageously, the jet fracturing element 12 is positioned below the separation plate 6 and below the injection / extraction tank 9, substantially in the center of panel 3, i.e., substantially along the central axis Z of panel 3.

[0058] Referring to Figures 1 and 2, the jet fracturing element 12 comprises two solid jet fracturing plates 13 with a width l, extending on both sides of (and from) the injection / extraction tank 9 toward the side walls 10 of panel 3. According to one or more embodiments, the jet fracturing element 12 also comprises an optional central body 14 located below the injection / extraction tank 9 and connecting the two solid jet fracturing plates 13.

[0059] Referring to Figure 1, the ratio l / L of the width l of each standard solid jet fracturing plate 13 to the width L of the side of the separation plate 6 is less than 0.05.

[0060] Referring to Figure 2, the ratio l / L of the width l of each solid jet fracturing plate 13 according to the present invention to the width L of the side of the separation plate 6 is at least 0.1, preferably at least 0.2, and very preferably at least 0.25. According to one or more embodiments, the ratio l / L is 0.1 to 0.7, preferably 0.2 to 0.4, and very preferably 0.25 to 0.30.

[0061] According to one or more embodiments, the jet fracturing element 12 extends over the entire width of the panel 3, preferably at least 10%, preferably at least 20%, and more preferably at least 25% of the width of the panel 3. According to one or more embodiments, the jet fracturing element 12 extends over a width between 10% and 70%, preferably between 20% and 40%, and more preferably between 25% and 30% of the width of the panel 3.

[0062] According to one or more embodiments, the jet fragmentation element 12 and the injection / extraction tank 9 are adjacent to each other in the sense that they are placed side by side. According to one or more embodiments, the jet fragmentation element 12, the lower screen, and the injection / extraction tank 9 are adjacent to each other in the sense that they are placed side by side.

[0063] According to one or more embodiments, the lower screen is, for example, a "Johnson®" type screen (where the slots are substantially perpendicular to the central axis of the panel). According to one or more embodiments, the lower screen 8 is a perforated plate.

[0064] According to one or more embodiments, the distance between the lower end of the separation plate 6 that separates the distributor 7 from the collector 5 and the upper end of the jet fragmentation element 12 is less than 10% of the width of the panel 3, preferably less than 6%.

[0065] According to one or more embodiments, the distance between the lower end of the separation plate 6 that separates the distributor 7 from the collector 5 and the upper end of the jet fragmentation element 12 is 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less.

[0066] According to one or more embodiments, the separation plate 6 has an opening between 1% and 10%, preferably between 4% and 8%.

[0067] According to one or more embodiments, the separation plate 6 is perforated with holes having a diameter of 5 mm to 50 mm and / or a center-to-center distance of 30 mm to 90 mm.

[0068] The present invention also relates to a plate Pi comprising a plurality of panels 3 according to the present invention.

[0069] Furthermore, the present invention relates to a separation column 1 divided into N adsorbent beds Ai separated by n plates Pi consisting of a plurality of panels 3 according to the present invention.

[0070] Furthermore, the present invention relates to an SMB separation apparatus that includes at least one separation column 1, which is divided into N adsorbent beds Ai separated by n plates Pi consisting of a plurality of panels 3 according to the present invention. [About this method] The present invention can also be defined as an SMB method comprising an SMB separation apparatus according to the present invention, wherein the raw materials to be separated are mixtures such as aromatics having 7 to 9 carbon atoms, a mixture of normal paraffins and isoparaffins, or a mixture of normal olefins and isoolefins.

[0071] Therefore, the present invention also relates to an SMB separation method using at least one separation column 1 divided into N adsorbent beds Ai separated by n plates Pi consisting of a plurality of panels 3 according to the present invention.

[0072] The remainder of this text refers to steps to indicate the operations or groups of operations performed on a given flow at a given point in time in the method. The method is described in various steps along the sequence of fluid or product flows.

[0073] The SMB separation method includes the following steps: supplying at least one raw material and desorbent to column 1, and withdrawing at least one extract and at least one raffinate from column 1. Column 1 is interconnected in a closed circuit and comprises one or more beds Ai of adsorbent solids (i.e., the last bed of the last adsorbent is configured to deliver the circulating fluid to the first bed of the first adsorbent), separated by plates Pi according to the present invention, wherein the supply and withdrawal points in plate Pi of column 1 are shifted over time by a value corresponding to one adsorbent bed with a switching time (denoted as ST), and multiple operating zones of the SMB apparatus, in particular the following main zones defined and indicated by number: - Zone I for desorption of the product to be separated, between the injection of the desorbing agent and the withdrawal of the extract. - Zone II, located between the extraction of the extract and the injection of the raw materials, for the desorption of isomers of the products to be separated. - Zone III, located between the injection of raw materials and the extraction of raffinate, for the adsorption of products to be separated, and - Zone IV, between the removal of raffinate and the injection of the desorbent. To decide.

[0074] According to one or more embodiments, the adsorbent bed is distributed to zones I to IV according to a / b / c / d type configuration, that is, the distribution of the bed is as follows: - Number of floors in Zone I, a - Number of floors in Zone II: b, - The number of floors in Zone III, c, and - This is considered to be the number of floors in Zone IV, d.

[0075] According to one or more embodiments, - a=(t*0.2)*(1±0.2), - b=(t*0.4)*(1±0.2), - c=(t*0.27)*(1±0.2), and, - d = (t * 0.13) * (1 ± 0.2), t is a natural integer between 6 and 24, preferably between 8 and 19 (for example, between 12 and 15).

[0076] According to one or more embodiments - a=(t*0.17)*(1±0.2), - b=(t*0.42)*(1±0.2), - c=(t*0.25)*(1±0.2), and, - d = (t * 0.17) * (1 ± 0.2), t is a natural integer between 6 and 24, preferably between 8 and 19, and more preferably between 12 and 15 (for example, 12 or 15).

[0077] According to one or more embodiments, the desorbent is selected from the group consisting of one or more isomers of diethylbenzene and toluene. According to one or more embodiments, the desorbent is paradiethylbenzene or toluene. According to one or more embodiments, the desorbent is toluene.

[0078] According to one or more embodiments, the adsorbent used includes or is composed of faujasite selected from the group consisting of BaX, BaKX, and BaLSX.

[0079] According to one or more embodiments, the raw material is essentially a mixture of C8 aromatic compounds (e.g., xylene and ethylbenzene). According to one or more embodiments, the mixture consists of at least 95%, preferably at least 97% (e.g., at least 99%) of essentially C8 aromatic compounds. According to one or more embodiments, the raw material contains at least 15 wt% paraxylene and / or 30 wt% metaxylene based on the total weight of the raw material.

[0080] One example of an industrially important SMB separation method is the separation of C8 aromatic fractions for the production of paraxylene of industrial purity, typically at least 99.7 wt%, as well as raffinates rich in ethylbenzene, orthoxylene, and metaxylene.

[0081] The resulting extract contains a desorbent, paraxylene, and optionally trace amounts of isomers (paraxylene purity of 95% or higher, preferably 98% or higher). This extract is treated to separate the desorbent (e.g., by distillation) and then purified by either crystallization or SMB adsorption to increase the purity of paraxylene.

[0082] According to one or more embodiments, the temperature in the adsorbent bed is between 140°C and 189°C, preferably between 155°C and 185°C, and more preferably between 170°C and 180°C.

[0083] The pressure is adjusted so that the liquid phase is maintained at all points in the method according to the present invention. According to one or more embodiments, the pressure in the adsorbent bed is between 1 MPa and 10 MPa, preferably between 2 MPa and 4 MPa, and more preferably between 2 MPa and 3 MPa.

[0084] According to one or more embodiments, the switching time ST used (time between two consecutive switching of feed / extract) is between 30 seconds and 100 seconds. Preferably, the switching time ST used is between 40 seconds and 80 seconds (e.g., 60 ± 10 seconds).

[0085] According to one or more embodiments, the surface velocity between floors is between 0.2 cm / s and 2.5 cm / s, preferably between 0.5 cm / s and 2 cm / s. [Examples] The effectiveness of the apparatus according to the present invention was tested by simulation.

[0086] The first simulation, referred to as Example 1, reproduces a standard plate Pi supplied to the adsorbent bed Ai, as shown in Figure 1.

[0087] The second simulation, referred to as Example 2, reproduces the plate Pi according to the present invention supplied to the adsorbent bed Ai, as shown in Figure 2.

[0088] In the two embodiments, the structural characteristics of the elements of the plate Pi and the elements of the adsorbent bed Ai are as follows: - The diameter of plate Pi is 9.7m. - The plate is divided into meridian panels, - The width of the meridian panel is 1.15m, and the floor height is 1.25m. - Separation plate 6 is perforated, - The jet fracturing element 12 and the lower screen 8 are welded to each other. - The lower screen 8 is perforated, - All elements are centered around the injection / extraction tank 9, - The adsorbent bed Ai is filled with zeolite sieves with a particle size centered around approximately 550 μm. - The adsorbent bed is filled to a height of 30 mm below the distributor 7. - Liquid is supplied to the adsorbent bed Ai at a surface velocity of 1.0 cm / s.

[0089] In Reference Example 1, the width l of the standard solid jet fracturing plate 13 is 3 cm.

[0090] In Example 2 of the present invention, the width l of the solid jet fracturing plate 13 according to the present invention is 15 cm.

[0091] This result is expressed using the Peclet number (Pe), which represents the ratio of fluid convection to dispersion due to axial diffusion. A larger Peclet number indicates smaller axial diffusion.

[0092] Reference example 1: Pe=120 Example 2 according to the present invention: Pe=170 Minimizing axial dispersion is particularly beneficial for methods implementing fixed beds of solid particles, including adsorption methods. [Explanation of Symbols]

[0093] 1: Pseudo-moving bed separation column 2: Solid particle bed 3: Panel 4: Top screen 5: Collector 6: Separation plate 7:Distributor 8: Lower screen 9: Injection / extraction tank 10: Side wall 11:Exit opening 12: Jet fracturing element 13: Solid jet fracturing plate Ai: Downstream adsorbent bed Ai-1: Upstream adsorbent bed E: Flow of the main fluid Pi: Distribution and collection plate

Claims

1. A device for distributing / collecting a main fluid, said device being adapted to feed a downstream adsorbent bed (Ai) of a simulated moving bed separation column (1), said device comprising at least one panel (3), said panel (3) being arranged in the direction of the main fluid flow (E): an upper screen (4) adapted to support the bed of solid particles (2) of the upstream adsorbent bed (Ai-1); a collector (5) adapted to collect the main fluid leaving the upstream adsorbent bed (Ai-1), a separating plate (6) separating the collector (5) from the distributor (7) and including at least one outlet opening (11) for directing the main flow from the collector (5) towards the distributor (7); a distributor (7) adapted to distribute the main stream over the downstream adsorbent beds (Ai), and - equipped with a lower screen (8), The panel further comprises: - an inlet / outlet tank (9) adjacent to the separating plate (6) and arranged in a substantially central position of the panel (3), the separating plate (6) including two sides located on either side of the inlet / outlet tank (9), each side extending over a width L from the inlet / outlet tank (9) to a side wall (10) of the panel (3); - jet break-up elements (12) extending perpendicular to the direction of the main fluid flow (E), The jet breakage element (12) comprises two solid jet breakage plates (13), which are: o Extending on both sides of the inlet / outlet tank (9), o juxtaposed with the lower screen (8), o located below at least one outlet opening (11), o the main flow in the distributor (7) is directed perpendicular to the direction of the main fluid flow (E), In the panel, the ratio l / L of the width l of each solid jet crushing plate (13) to the width L of the side of the separating plate (6) is at least 0.

1.

2. 2. The device according to claim 1, wherein the jet-breaking element (12) comprises a central body, which is arranged below the injection / withdrawal tank (9) and connects two solid jet-breaking plates (13).

3. 3. The device according to claim 1 or 2, wherein the ratio l / L of the width l of each solids jet crushing plate (13) to the width L of the side of the separating plate (6) is at least 0.2, preferably at least 0.

25.

4. 2. The apparatus according to claim 1, wherein the ratio l / L of the width l of each solid jet crushing plate (13) to the width L of the side of the separation plate (6) is 0.1 to 0.7, preferably 0.2 to 0.4, more preferably 0.25 to 0.

30.

5. 2. The device according to claim 1, wherein the jet breaker element (12) and the injection / withdrawal tank (9) are arranged side by side.

6. 2. The device according to claim 1, wherein the distance between the lower end of the separating plate (6) and the upper end of the jet breaker element (12) is less than 10%, preferably less than 6%, of the width of the panel (3).

7. 2. Device according to claim 1, wherein the separating plate (6) has an opening degree between 1% and 10%, preferably between 4% and 8%.

8. 2. The device according to claim 1, wherein the separating plate (6) is perforated with holes having a diameter of 5 mm to 50 mm and / or a center-to-center distance of 30 mm to 90 mm.

9. A distributor-collection plate (Pi) of a simulated moving bed separation column (1), the plate (Pi) comprising a plurality of devices according to claim 1.

10. A simulated moving bed separation column (1) comprising a plurality of plates (Pi) according to claim 9.

11. Column (1) according to claim 10, divided into N adsorbent beds (Ai) separated by n plates (Pi), the number N of adsorbent beds (Ai) and the number n of plates (Pi) being the same and ranging from 4 to 24, preferably from 8 to 19, more preferably from 12 to 15.

12. A simulated moving bed separation unit comprising at least one column (1) according to claim 10 or 11.

13. 1. A simulated moving bed separation process comprising the steps of: supplying at least one feed and desorbent to at least one column (1); withdrawing at least one extract and at least one raffinate from the column (1); The column (1) comprises one or more beds of adsorbent solid (Ai) interconnected in a closed circuit and separated by plates (Pi) comprising a plurality of devices according to claim 1, the feed and withdrawal points in the plates (Pi) of the column (1) being shifted over time by a value corresponding to one adsorbent bed with a switching time, and a plurality of operating zones of the column (1), in particular the following main zones defined and indicated by numbers: a zone I for desorption of the products to be separated, between the injection of the desorbent and the withdrawal of the extract; Zone II for desorption of the product isomers to be separated, between the withdrawal of the extract and the injection of the feedstock. a zone III for adsorption of the products to be separated, between the injection of the feed and the withdrawal of the raffinate, and Zone IV, between the withdrawal of the raffinate and the injection of the desorbent Determine In this method, the adsorbent beds are distributed among zones I-IV according to an a / b / c / d type configuration, i.e., the bed distribution is as follows: - number of beds a in zone I, - number of beds in zone II b, the number c of beds in zone III, and - number of floors in zone IV d, It is said that, In this method, - a=(t*0.2)*(1±0.2), - b=(t*0.4)*(1±0.2), c = (t * 0.27) * (1 ± 0.2), and - d=(t*0.13)*(1±0.2), or, - a=(t*0.17)*(1±0.2), - b=(t*0.42)*(1±0.2), c = (t * 0.25) * (1 ± 0.2), and - d=(t*0.17)*(1±0.2) It is said that, In this method, t is a natural integer between 6 and 24, preferably between 8 and 19, more preferably between 12 and 15.

14. Operating conditions: the feedstock contains a mixture of aromatics containing 8 carbon atoms; the desorbent is selected from the group consisting of one or more isomers of diethylbenzene and toluene, preferably the desorbent is para-diethylbenzene or toluene, more preferably the desorbent is toluene; the adsorbent used comprises or consists of a faujasite selected from the group consisting of BaX, BaKX and BaLSX; The method of claim 13 , comprising at least one of:

15. Operating conditions: a temperature in the adsorbent bed of between 140°C and 189°C, preferably between 155°C and 185°C, more preferably between 170°C and 180°C; the pressure in the adsorbent bed is between 1 and 10 MPa, preferably between 2 and 4 MPa, more preferably between 2 and 3 MPa; the switching time is between 30 and 100 seconds, preferably between 40 and 80 seconds; the superficial velocity between the beds is between 0.2 and 2.5 cm / s, preferably between 0.5 and 2 cm / s; 15. The method of claim 13 or claim 14, comprising at least one of:

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