Radial separation device for simulated moving floors

Abstract

The present invention relates to a device, column and method for radial separation or reaction, wherein the adsorption chamber (9) has a packing height (H3) that is greater than the height of the distribution channel (6) and the height of the collection channel (8), and the upper wall (2) of the adsorption chamber (9) comprises at least one wash solvent inlet (6).

Description

Technical Field

[0001] The present invention relates to a radial device for separating or reacting fluids, for example, in a separation method such as a simulated moving bed separation method, especially for xylene, or in a reaction method such as a catalytic reforming method. <00000​​​​​​​​​​​​​​​​​​​​​​​In contrast, the use of fluid-sealing textiles is difficult to apply to radial applications of SMB separation devices. This is because clogging of parts of the adsorption chamber between the distribution duct and the collection duct by fluid-sealing textiles is detrimental to the performance of the separation method and can even lead to the creation of a fluid-stagnant chamber (also called a "dead" volume), which is a disruption to the fluid distribution and collection system. This hydrodynamic disruption causes flow imbalance and further detrimental to the performance of the method. [Overview of the project] [Means for solving the problem]

[0006] (Summary of the invention) In a first embodiment, the present invention provides a device for radial separation (e.g., in a simulated moving bed) or reaction (e.g., catalytic modification) comprising a cylinder container, the following: - side wall, - Upper wall, - Lower wall, - At least one inlet for the fluid to be separated, - At least one vertical distribution duct, - At least one fluid outlet, - At least one vertical collection duct, - An adsorption chamber designed to contain a floor of (solid) adsorbent; the adsorption chamber is located between the distribution duct and the collection duct and extends from the upper wall to the lower wall. - At least one distribution grid positioned between the distribution duct and the adsorption chamber, and - At least one collection grid positioned between the collection duct and the adsorption chamber. It includes, - The adsorption chamber has a filling height that is higher than the height of the distribution duct and the height of the collection duct, - The upper wall includes at least one inlet for washing the solvent. Related to things.

[0007] Advantageously, the device according to the present invention makes it possible to keep the distribution and collection surface area, particularly the surface area at the upper end of the adsorption chamber, constant over time, despite the phenomenon of the adsorbent bed being compressed over time. Thus, the device according to the present invention also makes it possible for the system to maintain a high level of separation performance.

[0008] According to one or more embodiments, the filling height is at least 1% higher than the height of the distribution duct and the height of the collection duct.

[0009] According to one or more embodiments, the filling height is 1 to 10% higher than the height of the distribution duct and the height of the collection duct.

[0010] According to one or more embodiments, the filling height is 1.5 to 7% higher than the height of the distribution duct and the height of the collection duct.

[0011] According to one or more embodiments, the at least one washing solvent inlet is designed to provide a washing solvent flow rate such that the ratio of the washing solvent flow rate to the fluid flow rate is between 0.001 and 0.15.

[0012] According to one or more embodiments, the at least one washing solvent inlet comprises a plurality of washing solvent orifices distributed across the cross-section of an additional adsorbent solid and / or a porous plate and / or a distribution plate.

[0013] According to one or more embodiments, the device further comprises a central wall parallel to the side walls.

[0014] According to one or more embodiments, the distribution duct and collection duct are suitable for downward or upward flow of fluid.

[0015] According to one or more embodiments, the distribution duct is in the center and the collection duct is around the periphery, or the distribution duct is around the periphery and the collection duct is in the center.

[0016] According to one or more embodiments, the lower limit of the adsorption chamber corresponds to the lower limits of the distribution duct and the collection duct.

[0017] In a second aspect, the present invention relates to a column comprising at least one device according to the first aspect.

[0018] In a third aspect, the present invention relates to a method of separation or reaction using a plurality of devices according to the first aspect or a plurality of columns according to the second aspect, the method being as follows: - A fluid is introduced into the distribution duct, the fluid is distributed into the adsorption chamber and collected in the collection duct, and - A washing solvent is introduced into the adsorption chamber, and the washing solvent is collected together with the fluid in the collection duct.

[0019] Other features and advantages of the present invention according to the foregoing aspects will become apparent by reading the following description, considering non-limiting exemplary embodiments, while referring to the accompanying drawings described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [Figure 1] FIG. 1 shows an axially symmetric cross-sectional view on the vertical axis Z of a reference device for radial separation by SMB. [Figure 2] FIG. 2 shows an axially symmetric cross-sectional view on the vertical axis Z of the device according to FIG. 1, with a fluid-tight textile added to close the upper part of the adsorption chamber after the solid adsorbent forming the adsorbent bed has been compressed. [Figure 3] FIG. 3 shows an axially symmetric cross-sectional view on the vertical axis Z of a device according to one embodiment of the present invention for radial separation by SMB, with an additional height of solid adsorbent added to the upper part of the adsorption chamber. [Figure 4] FIG. 4 shows an axially symmetric cross-sectional view on the vertical axis Z of the device according to FIG. 3, with the additional height of adsorbent solid filled to account for the compression of the solid adsorbent due to flowing under the influence of gravity. [Modes for carrying out the invention]

[0021] (Description of the embodiment) The present invention can be defined as a radial device (e.g., a reactor) for the separation (e.g., by SMB) of a compound (e.g., xylene) or the reaction (e.g., catalytic reforming) of a compound (e.g., naphtha). The radial device may be arranged in particular in one or more columns (e.g., in series), particularly for SMB separation of xylene (e.g., paraxylene), where one or more columns are divided into N radial devices, each containing N adsorbent beds, and the N adsorbent beds are separated by 2N interbed zones (i.e., N distribution zones and N collection zones). Preferably, the number N is between 4 and 24, preferably between 8 and 15, and very preferably between 8 and 12.

[0022] Referring to Figure 1, the reference device for radial separation by SMB includes a cylindrical container having cylindrical side walls (1), a top wall (2), a bottom wall (3), and optionally a central wall (4) parallel to the side wall (1), i.e., vertically positioned to enhance the robustness of the container. This container further includes: - At least one inlet (5) adjacent to the upper wall (2) for the fluid to be separated (hereinafter referred to as the upper inlet); - At least one vertical distribution duct (6), for example, extending from the upper inlet (5) to the lower wall (3); - At least one fluid outlet (7) adjacent to the lower wall (3) (hereinafter referred to as the lower outlet); and - At least one vertical collection duct (8), for example, extending upward from the lower outlet (7) to a height substantially equal to (within ±10%, preferably within ±5%) the height of the distribution duct (6).

[0023] The container further comprises an adsorption chamber (9) (for example, a cylindrical tubular shape), which is positioned between the distribution duct (6) and the collection duct (8), extending from the upper wall (2) to the lower wall (3), and is designed to have an adsorbent bed (10) over a duct height H1 corresponding to the heights of the distribution duct (6) and the collection duct (8). The device further comprises at least one distribution grid (11), or any other means known to those skilled in the art for distributing liquid, such as a perforated plate, positioned between the distribution duct (6) and the adsorption chamber (9), and at least one collection grid (12), positioned between the collection duct (8) and the adsorption chamber (9), wherein the distribution grid (11) and the collection grid (12) allow the passage of fluid between the distribution duct (6) and the collection duct (8) and the adsorption chamber (9). In this example in Figure 1, the fluid flow within the device is a downward flow, i.e., the fluid enters the device through the upper inlet (5) and exits the device through the lower outlet (7). In contrast, the fluid flow may be an upward flow from the lower inlet to the upper outlet. Furthermore, in this example in Figure 1, the radial flow of fluid within the adsorption chamber (9) is an outward flow, i.e., from the central upper inlet (5) to the lateral lower outlet (7). In contrast, the radial flow of fluid within the adsorption chamber (9) may be an inward flow, i.e., from the periphery upper / lower inlets to the central lower / upper outlet. It will also be understood that the radial device according to this application may be rotatable by 90°, i.e., may have horizontal distribution ducts (7) and collection ducts (8).

[0024] As shown in Figure 1, under normal operation, the adsorbent bed (10) completely (e.g., at least 99%) fills the adsorption chamber (9). Referring to Figure 2, if the solid adsorbent (particles) forming the adsorbent bed (10) is compressed from duct height H1 to a height H2 lower than duct height H1 during device operation, one solution known to those skilled in the art is to add a fluid-sealing textile (13) to the adsorption chamber (9) to seal the top (14) of the adsorption chamber (9), and thus prevent fluid from flowing through zones without adsorbent. In contrast, the presence of a fluid-sealing textile (13) on the top (14) of the adsorption chamber (9) results in fluid retention that is detrimental to the performance of the separation method. In this example, the stagnant volume is noticeably observed at the top of the collection duct (8), which in turn causes changes in the hydrodynamics in the distribution duct (6) and reduces the cross-section open to the liquid passage toward the adsorbent bed (10), which is detrimental to performance.

[0025] Referring to Figure 3, the device for radial separation by SMB according to the present invention includes the same elements as referenced in the reference device, from (1) to (12). Furthermore, in the device according to the present invention, the packing height H3 from the upper wall (2) to the lower wall (3) of the adsorption chamber (9) is higher than the heights of the distribution duct (6) and the collection duct (8). In this way, the upper part (14) of the adsorption chamber (9) is adapted so that it can accommodate an additional height of adsorbent solid (15), and the adsorbent bed (10) has a packing height H3 that is at least 1%, preferably at least 3%, and very preferably at least 5%, higher than the heights of the distribution duct (6) and the collection duct (8). According to one or more embodiments, the packing height of the adsorbent bed is 1 to 10%, preferably 1.5 to 7%, higher than the heights of the distribution duct and the collection duct.

[0026] Referring to Figure 4, when the adsorption chamber (9) is filled with an adsorbent bed (10) having a filling height H3 that is higher than the duct height H1 of the distribution duct (6) and collection duct (8), if the solid in the adsorbent bed (10) is compressed during the operation, a portion of the added height of the adsorbent solid (15) is advantageously accompanied by the compression by flowing under the influence of gravity, and thus it is possible to maintain a compressed height H4 that is at least equal to or greater than the duct height H1. According to one or more embodiments, the filling height H3 is designed such that the compressed height H4 is at least 1.0 times, preferably 1.02 times, and very preferably 1.04 times higher than the duct height H1.

[0027] According to one or more embodiments, the lower limit of the adsorption chamber (9) (e.g., corresponding to the position of the lower wall (3)) also corresponds to the lower limits of the distribution duct (6) and the collection duct (8). According to one or more embodiments, the upper limit of the adsorption chamber (9) (e.g., corresponding to the position of the upper wall (2)) is at least 1.01 times, preferably 1.05 times, and very preferably 1.10 times higher than the upper limits of the distribution duct (6) and the collection duct (8).

[0028] Referring to Figures 3 and 4, the device according to the present invention further comprises at least one washing solvent inlet (16) located on the upper wall (2) of the container. The washing solvent inlet (16) allows, in particular, the introduction of the washing solvent into the adsorption chamber (9) to wash an additional height of the adsorbent solid (15) and to restrict the fluid flow at the additional height of the adsorbent solid (15). According to one or more embodiments, the washing solvent is a compound used as a desorbent in the SMB separation method. According to one or more embodiments, the washing solvent is selected from toluene and 1,4-diethylbenzene. According to one or more embodiments, the ratio of the flow rate of the washing solvent to the flow rate of the fluid is between 0.001 and 0.15, preferably between 0.005 and 0.10, and very preferably between 0.01 and 0.08.

[0029] Advantageously, the additional height of the adsorbent solid (15) is swept away by the downward flow of the washing solvent and can be generated by the circulation of the fluid within the volume corresponding to the additional height of the adsorbent solid (15) (known as the deceleration zone), thereby limiting hydrodynamic disturbances that may cause hydrodynamic dispersion.

[0030] (Examples) Reference column A for SMB separation consists of 15 reference devices as shown in Figure 1, containing 15 adsorbent beds arranged in series, and is separated into 30 inter-bed zones. The volume of each bed is 29.4 m³. 3 The porosity of the floor is 32.8%. The performance levels achieved by column A are paraxylene (PX) purity of 99.7%, paraxylene yield of 97.7%, and productivity of 93.4 kg / h / m². 3 That is the case.

[0031] Reference column B for SMB separation consists of 15 reference devices as shown in Figure 2, and includes 15 adsorbent beds arranged in series, separated into 30 inter-bed zones. The volume of each bed is 29.4 m³. 3 The porosity of the bed is 32.8%. In column B, the solid adsorbent experiences a compression of 8 vol% during operation in 15 beds, which is filled by a fluid-sealed textile placed in the adsorption chamber and adheres to the surface of the bed due to the pressure increase. By changing the unit settings to achieve the same level of paraxylene purity (99.7%) and yield (97.7%) as reference column A, the productivity of the system is 72.3 kg / h / m 3 It declined to a 22.5% loss.

[0032] Column C according to the present invention for SMB separation consists of 15 devices according to the present invention as shown in Figure 3, and includes 15 adsorbent beds arranged in series, separated by 30 inter-bed zones. The volume of each bed is 29.4 m³. 3The porosity of the bed is 32.8%. In column C, the solid adsorbent in bed 15 experiences a compression of 8 vol% during operation, which is filled by an additional 10.0% height of the adsorbent solid (15) placed at the top (14) of the adsorption chamber (9). Therefore, the additional volume of the adsorbent solid is 2.9 m³. 3 This is obtained in each adsorbent bed, and each of these additional volumes is swept away by a downward flow of washing solvent equivalent to 4% of the total "pump-around" flow rate circulating in the unit. By modifying the unit settings to achieve the same level of paraxylene purity (99.7%) and yield (97.7%) as reference column A, the system productivity is 83.4 kg / h / m³. 3 It decreased to a loss of exactly 10%.

Claims

1. A pseudo-movable floor separation method using a cylindrical container, wherein the cylindrical container is as follows: - side wall (1), - Upper wall (2), - Lower wall (3) - At least one inlet (5) for the fluid to be separated, - At least one vertical distribution duct (6), - At least one fluid outlet (7), - At least one vertical collection duct (8), - An adsorption chamber (9) designed to include a solid adsorbent bed (10); the adsorption chamber (9) is located between the distribution duct (6) and the collection duct (8) and extends from the upper wall (2) to the lower wall (3), - At least one distribution grid (11) positioned between the distribution duct (6) and the adsorption chamber (9), and - At least one collection grid (12) positioned between the collection duct (8) and the adsorption chamber (9) It includes, - The filling height (H3) of the adsorption chamber (9) is higher than the height of the distribution duct (6) and the height of the collection duct (8), - The upper wall (2) includes at least one inlet (16) for the washing solvent. In this method, - The fluid is introduced into the distribution duct (6), the fluid is distributed in the adsorption chamber (9), and collected in the collection duct (8), and - The washing solvent is introduced into the adsorption chamber (9), and the washing solvent is collected together with the fluid in the collection duct (8). method.

2. The method according to claim 1, wherein the filling height (H3) is at least 1% higher than the height of the distribution duct (6) and the height of the collection duct (8).

3. The method according to claim 2, wherein the filling height (H3) is 1 to 10% higher than the height of the distribution duct (6) and the height of the collection duct (8).

4. The method according to claim 3, wherein the filling height (H3) is 1.5 to 7% higher than the height of the distribution duct (6) and the height of the collection duct (8).

5. The method according to any one of claims 1 to 4, wherein the at least one washing solvent inlet (16) comprises a plurality of washing solvent orifices (16) distributed on an adsorbent solid and / or a perforated plate and / or a distribution plate.

6. The method according to any one of claims 1 to 5, further comprising a central wall (4) parallel to the side wall (1).

7. The method according to any one of claims 1 to 6, wherein the distribution duct (6) and the collection duct (8) are suitable for downward or upward fluid flow.

8. The method according to any one of claims 1 to 7, wherein the distribution duct (6) is in the center and the collection duct (8) is around it, or the distribution duct (6) is around it and the collection duct (8) is in the center.

9. The method according to any one of claims 1 to 8, wherein the lower limit of the adsorption chamber (9) corresponds to the lower limits of the distribution duct (6) and the collection duct (8).

10. The method according to any one of claims 1 to 9, wherein the washing solvent is provided to the washing solvent inlet (16) at a flow rate such that the ratio of the flow rate of the washing solvent to the flow rate of the fluid is between 0.001 and 0.15.

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