阅读说明：本技术 具有收集网络的分隔的使用子午线嵌板的分布装置 (Distribution device using radial panels with separation of the collection network ) 是由 F·奥捷 A·罗永-勒博 M·弗拉蒂 于 2020-04-17 设计创作，主要内容包括：本发明涉及一种用于模拟移动床分离单元的分布和收集装置以及方法,其中支撑吸附剂床(6)的板(n)被划分为子午线嵌板(12),所述子午线嵌板包括收集通道(8)、分布通道(4)、以及用于分隔收集通道和分布通道的分隔板(11),其中提供了在塔外部的多个外围导管,以便将子午线嵌板的收集通道唯一地连接到同一个子午线嵌板的分布通道。(The invention relates to a distribution and collection device and a method for a simulated moving bed separation unit, wherein a plate (n) supporting adsorbent beds (6) is divided into radial panels (12) comprising collection channels (8), distribution channels (4), and partition plates (11) for separating the collection and distribution channels, wherein a plurality of peripheral ducts outside the column are provided in order to connect the collection channels of a radial panel exclusively to the distribution channels of the same radial panel.)

1. A distribution and collection apparatus for a simulated moving bed separation unit having a diameter of more than 1 meter, the apparatus comprising at least one column divided into a plurality of adsorbent beds (6) and a plate (n) supporting the adsorbent beds (6), wherein:

at least one plate (N) positioned between the first and second adsorbent beds (N +1, N) is divided into meridian panels (12) parallel and continuous to each other so as to cover a section of said plate (N); and is

Each radial panel (12) comprising a collection channel (8) adapted to extract a fluid from the first adsorbent bed (N), a distribution channel (4) adapted to distribute the fluid towards the second adsorbent bed (N + 1), and a partition plate (11) for partitioning the collection channel (8) and the distribution channel (4),

the device further comprises a plurality of peripheral ducts (10) external to the tower, each peripheral duct (10) being adapted to connect a collecting channel (8) of a radial panel exclusively to the distribution channel (4) of the radial panel.

2. The distribution and collection device according to claim 1, wherein the distribution channels (4) and the collection channels (8) have heights that vary linearly over the length of the meridian panel (12), such that: the sum of the heights of the distribution channels (4) and of the collection channels (8) taken at any point on the length of the meridian panel (12) is substantially constant; and the inlet velocity of the particles or molecules of the fluid into the second adsorbent bed (N + 1) remains substantially constant over the entire length of the meridian panel from the inlet point of the distribution channel (4).

3. The distribution and collection device according to claim 1 or claim 2, wherein the plate (n) is divided into between 2 and 12 radial panels (12).

4. A distribution and collection device according to any one of the preceding claims, wherein the peripheral conduit (10) comprises at least one injection or extraction point (9) for injecting a feedstock or solvent into the column or extracting a raffinate or extract from the column.

5. The distribution and collection device according to any one of the preceding claims, comprising a plurality of upper grids (7) and lower grids (5), the meridian panels (12) of the plate (N) being positioned between the lower grids (5) of the first adsorbent beds (N) and the upper grids of the second adsorbent beds (N + 1).

6. The distribution and collection device according to any one of the preceding claims, wherein the length of the peripheral conduits (10) connected to the plates (n) is predetermined so as to allow the same residence time of the particles or molecules of the fluid through the peripheral conduits (10).

7. A distribution and collection device according to any one of the preceding claims, wherein each peripheral duct (10) substantially follows the periphery of the tower from the collection channel (8) to the distribution channel (4).

8. A distribution and collection device according to any one of the preceding claims, wherein the peripheral duct (10) is substantially horizontal and is located at the periphery of the plate (n) to which the peripheral duct (10) is connected.

9. Distribution and collection device according to any one of the preceding claims, wherein at least one peripheral duct (10) comprises at least one vertical portion.

10. The distribution and collection device according to any one of the preceding claims, wherein the collection channel (8) comprises a plurality of exit points (13) and the distribution channel (4) comprises a plurality of entry points (14), the plurality of exit points (13) being connected to the plurality of entry points (14) by a single peripheral duct (10).

11. A method of using a distribution and collection device according to any one of claims 1 to 10, the method comprising the steps of:

drawing fluid from the first adsorbent bed (N) via said collection channels (8) of the meridian panel (12) of the plate (N);

-sending the fluid exclusively from the collection channel (8) to a peripheral duct (10);

sending the fluid from the peripheral duct (10) exclusively to the distribution channels (4) of the radial panel (12);

distributing the fluid from the distribution channel (4) into a second adsorbent bed (N + 1).

12. Process according to claim 11 for the separation of xylenes in a simulated moving bed operating with a number of beds comprised between 4 and 24.

13. The method of claim 11 or claim 12, further comprising the step of: controlling the flow rate of the distribution channels (4) of the plate (N) to supply fluids to the second adsorbent bed (N + 1) at substantially equal rates.

14. Method according to any one of claims 11 to 13, wherein the maximum discharge speed of the fluid in the peripheral duct (10) is less than or equal to 6 m/s.

15. The method according to any one of claims 11 to 14, wherein the peripheral conduits (10) operate with substantially the same residence time.

Technical Field

The present invention relates to a device for introducing and collecting fluids in a process for separating xylenes in a simulated moving bed and to a unit using said process, more particularly a unit of large diameter (D > 1 m) and having a plurality of separation stages, in which the product is injected or withdrawn between two stages.

Background

The current technology for separation by simulated moving bed (abbreviated SMB in the remainder of the text) uses units with a certain number of common features:

-a succession of adsorbent beds within which a fluid flows according to a "pump around" flow; the pumparound flow generally represents a number of times (between about 1.5 and 6 times) the incoming feed flow rate,

a system for injecting raw materials and solvents and for extracting the effluents, known as extracts and raffinates,

-a collection and redistribution system for transferring from one bed to the next.

In processes for separation by simulated moving bed adsorption, there are generally multiple beds located in one or two adsorption columns. Located between each bed is a distributor-mixer-extractor or "DME" panel (panel) supplied by a pipeline, usually in the shape of a "distribution/extraction spider". Each DME panel located between two successive beds is connected to the outside by means of one or two pipelines or networks leading to valves which successively put each bed in communication with each stream (stream) entering or leaving the adsorption section. This operation is performed sequentially, and the time to return to the initial bed at the end is referred to as the cycle time.

For example, patent US2985589 explicitly shows that each injection or extraction network is connected via a single line to a valve which connectively connects the feedstock, extract, solvent and then raffinate. A disadvantage of this way of proceeding is that the performance of the process is greatly reduced, since each stream is thus contaminated by the contents of the common line. Therefore, it is essential to install a flushing system.

Several patents explain how these flushing operations are carried out, in particular the patents FR2751888, FR2772634, FR 2870751.

Flushing operations generally prove to be expensive in terms of investment (e.g., additional valves and piping) and also in terms of operating costs (throughput, productivity).

The "distribution/extraction spiders" constitute obstacles within the adsorbent bed that interfere with the flow in the bed. Obstacles in beds have operating costs in terms of productivity and yield. Patent WO 09133254 shows how to minimize the effect of obstacles on the fluid dynamics in the bed. Augier et al, 2008 (Separation and Purification Technology 63, pp 466-474) evaluated the cost of obstacles.

Disclosure of Invention

According to a first aspect, the present invention relates to a distribution and collection apparatus for a simulated moving bed separation unit having a diameter greater than 1 meter, the apparatus comprising at least one column divided into a plurality of adsorbent beds and a plate supporting the adsorbent beds, wherein: at least one plate positioned between a first adsorbent bed and a second (underlying) adsorbent bed is divided into mutually parallel and continuous radial panels so as to cover a cross section of the plate; and each radial panel comprising a collection channel adapted to withdraw fluid from the first adsorbent bed, a distribution channel adapted to distribute fluid towards the second adsorbent bed, and a partition plate for partitioning the collection channel and the distribution channel, the device further comprising a plurality of peripheral ducts outside the tower, each peripheral duct being adapted to connect the collection channel of the radial panel exclusively to the distribution channel of said radial panel.

Advantageously, the device according to the invention makes it possible: ensuring that the "pump around" flow is collected completely at each panel, so as to eliminate flushing operations; minimizing obstructions within the bed; and to adhere to an almost equal residence time for the fluid in the network outside the column and also in the column.

According to one or more embodiments, the distribution channels and the collection channels have heights that vary linearly over the length of the meridian panel such that: the sum of the heights of the distribution channels and collection channels taken at any point along the length of the meridian panel is substantially constant; and the inlet velocity of particles or molecules of the fluid into the second adsorbent bed remains substantially constant throughout the length of the meridian panel from the inlet point of the distribution channel.

According to one or more embodiments, the plate is divided into between 2 and 12 radial panels.

According to one or more embodiments, the peripheral conduit comprises at least one injection or extraction point for injecting feedstock or solvent into the column or extracting raffinate or extract from the column.

In accordance with one or more embodiments, the apparatus includes a plurality of upper and lower grids, the meridian panels of the plate being positioned between the lower grid of the first adsorbent bed and the upper grid of the second adsorbent bed.

According to one or more embodiments, the length of the peripheral ducts connected to the plate is predetermined so as to allow the residence time of the particles or molecules of the fluid passing through said peripheral ducts to be the same.

According to one or more embodiments, each peripheral duct substantially follows the circumference of the tower from the collecting channel to the distribution channel.

According to one or more embodiments, the peripheral ducts are substantially horizontal and located at the periphery of the plate to which they are connected.

According to one or more embodiments, the at least one peripheral duct comprises at least one vertical portion.

According to one or more embodiments, the collection channel comprises a plurality of exit points and the distribution channel comprises a plurality of entry points, said plurality of exit points being connected to said plurality of entry points by a single peripheral duct.

According to a second aspect, the invention relates to a method of using a device according to the first aspect, the method comprising the steps of: withdrawing fluid from the first adsorbent bed via the collection channels of the meridian panel of the plate; sending fluid exclusively from the collection channel to the peripheral catheter; sending fluid from a peripheral conduit exclusively to the distribution channels of the radial panel; distributing the fluid from the distribution channel into the second adsorbent bed.

According to one or more embodiments, the process is used for separating xylenes in a simulated moving bed operating with a number of beds between 4 and 24.

According to one or more embodiments, the method further comprises the steps of: the flow rates of the distribution channels of the plate are controlled to supply fluids to the second adsorbent bed at substantially equal rates.

According to one or more embodiments, the maximum discharge velocity of the fluid in the peripheral duct is less than or equal to 6 m/s.

According to one or more embodiments, the peripheral conduits operate at substantially the same residence time.

Other features and advantages of the present invention of the above-described aspects will become apparent upon reading the following description of the non-limiting exemplary embodiments with reference to the drawings described below.

Drawings

FIG. 1 shows 3 successive adsorbent beds 6 (labeled N-1, N, and N +1 from top to bottom) and a plate N positioned between the adsorbent beds N and N + 1. It makes it possible to clearly visualize the distribution channels 4 and the collection channels 8, which are symmetrical with respect to each other and are separated by a wall 11, wherein in particular the fluid passes from the exit point 13 of the collection channel 8 to the entry point 14 of the distribution channel 4 supplying bed N +1 via the peripheral duct 10 originating from bed N.

Fig. 2 corresponds to a top view of the tower, based on a cross-section along line a-a of fig. 1. It makes it possible to visualize and divide the plate n into radial panels and also to collect the fluid via the exit points 13 of the collection channels 8 to the entry points 14 of the distribution channels 4. These collections via the peripheral ducts 10 remain separate from each other. Each peripheral duct 10 connects the exit point 13 of the collecting channel 8 of a radial panel to the distribution channel 4 of the same radial panel.

Fig. 3 is a visualization produced by digital simulation. Which is a top-to-bottom cross-sectional view of the distribution channel 4 of the adsorbent bed N (designated 6), the adsorbent bed N and the collection channel 8 of the adsorbent bed N along the same cross-sectional plane as the cross-sectional plane of fig. 1. The entry point 14 into the distribution channel 4 is via the upper left edge. The adsorbent bed N is the region between the two grids 5 and 7 depicted by dotted lines. The exit point 13 of the collecting channel 8 is via the lower right edge. Zones a to O refer to the average internal residence time (average internal) of the fluid in the bed in seconds.

Detailed Description

The invention can be defined as a distribution and collection device for a simulated moving bed separation unit having a diameter of more than 1 meter, preferably more than 4 meters, very preferably more than 7 meters.

The plant comprises at least one separation column divided into N adsorbent beds supported by N plates (or interbed zones), each plate itself being divided into meridian panels, i.e. into panels (or cells) parallel and consecutive to each other so as to ensure a complete covering of the horizontal section of the plate.

Preferably, the number N of adsorbent beds and the number N of panels are the same and between 4 and 24, and preferably between 8 and 12. According to one or more embodiments, each plate is divided into between 2 and 12 radial panels, preferably between 4 and 8 radial panels.

Each radial panel comprises a collecting channel and a distribution channel separated from each other by a partition plate.

The withdrawal of the fluid from the adsorbent bed N is performed by the collection channels of the radial panel and the distribution of said fluid to the adsorbent bed N +1 located (directly) downstream of the adsorbent bed N is performed exclusively by the distribution channels of the same radial panel. Thus, each plate N comprises a plurality of radial panels, each radial panel comprising the collection channels of the adsorbent beds N and the distribution channels of the adsorbent beds N + 1.

Furthermore, the distribution and collection device according to the invention comprises a plurality of peripheral ducts outside the tower, each peripheral duct connecting only the collection channels of the radial panel to the distribution channels of said radial panel.

According to one or more embodiments, said peripheral conduits further make it possible to carry out the injection of raw materials and solvents from the outside to the column and the extraction of the raffinates and extracts from the column to the outside.

Advantageously, the device according to the invention can be applied to a simulated moving bed unit.

Advantageously, the device according to the invention makes it possible to ensure complete collection of the "pump around" stream, so as to eliminate the flushing operation. In a simulated moving bed unit, complete collection of the "pump around" stream is a paramount issue because it makes it possible to eliminate the flushing operation.

Advantageously, the device according to the invention makes it possible to minimize obstructions in the bed.

Advantageously, the device according to the invention has the following distinctive features: almost equal residence times are adhered to for the flow through the adsorbent bed N, the radial panel of plate N, and the adsorbent bed N + 1.

The technique described in the present invention uses the principle of compensating the residence times in the collection and distribution zones in order to minimize the difference, i.e. the difference in residence time of the fluid circulating in the cell as a function of the starting and ending points of said fluid. The inter-bed volume can be minimized by operating at the same velocity in the collection and distribution zones rather than at the same channel height. The total space requirement of the column can also be minimized by stacking the beds. Therefore, there is no specific inter-bed volume management.

According to one or more embodiments, the distribution channels and the collection channels have heights that vary linearly over the length of the radial panel, and the sum of the heights of the distribution channels and the collection channels taken at any point on the length of the radial panel is kept constant. In accordance with one or more embodiments, the heights of the distribution and collection channels are such that the inlet velocity of fluid particles or molecules into the adsorbent bed remains the same throughout the length of the meridian panel from the inlet point of the distribution channel.

In the present application, the length of the radial panel (which is the same as the length of the distribution channels and of the collection channels) refers to the dimension of the radial panel corresponding to the passage through the median portion of the radial panel along its maximum dimension (i.e. the length is substantially equal to the distance of the same radial panel between the exit point of the collection channels and the entry point of the distribution channels). In the present application, the width of the meridian panel (the width of the distribution channel and the collection channel) refers to the horizontal dimension perpendicular to the length, and the height refers to the vertical dimension perpendicular to the length. More specifically, the height of the distribution channels decreases linearly from the entry point (the end of the distribution channel connected to the peripheral duct) to the exit point of the collection channels (the end of the distribution channel opposite to the entry point), and the height of the collection channels decreases linearly from the exit point (the end of the collection channel connected to the peripheral duct) to the entry point of the distribution channels (the end of the collection channel opposite to the exit point). At each abscissa x corresponding to a standard point on the length of the meridian panel, the sum of the heights of the distribution channels and of the collection channels is constant.

Referring to fig. 1, the fluid originating from the adsorbent bed N-1 (labeled 1) is collected in the peripheral conduit 3 (via exit point 13).

Optionally, the injection into the peripheral catheter 3 and the extraction from the peripheral catheter 3 are carried out via the injection and extraction point 2.

The distribution channel 4 is supplied by the peripheral conduit 3 (via the entry point 14) and ensures a uniform flow rate of the fluid in the bed N (indicated as 6 in fig. 1) through the upper grid 5.

The fluid passing through the bed N is collected by the collection channel 8 through the lower grid 7.

In accordance with one or more embodiments, the adsorbent bed is defined by an upper grid and a lower grid, the meridian panel of the plate N being positioned between the lower grid of the adsorbent bed N and the upper grid of the adsorbent bed N + 1.

The collecting channel 8 supplies a peripheral duct 10 (via an exit point 13) for re-injection through the upper grid 5 into the bed N +1 located immediately below the bed N (via an entry point 14).

According to one or more embodiments, the peripheral conduit 20 comprises at least one injection or extraction point 9 outside the column for injecting the feedstock or solvent into the column or extracting the raffinate or extract from the column.

The separation plate 11 separates the collecting channel 8 from the distribution channel 4. The flatness of the partition plate 11 can be ensured by any means known to those skilled in the art. The partition plate 11 may be securely attached to the lower and upper grids 7 and 5, for example.

It is also possible to use tie rods extending over the entire width of the meridian panel, said tie rods being coupled to beams or plates defining said meridian panel at the height of the collection and distribution channels.

The height at the inlet point of the distribution channel 4 is defined by the maximum allowable discharge velocity in order not to destabilize the supply of the bed. According to one or more embodiments, the maximum allowable discharge velocity is between 0.1 m/s and 5 m/s, ideally between 0.5 m/s and 2.5 m/s.

The cross-section of the distribution channel 4 decreases linearly in order to ensure an almost uniform velocity over the entire length of the channel, for example equal to the maximum discharge velocity. This constancy of speed stems from the fact that: the flow velocity of the fluid is always proportional to the inlet section, this being the case at each inlet section of the channel. The height profile of the distribution channel is therefore linear in order to ensure this proportionality. Similarly, the cross-section of the collecting channel 8 increases linearly in order to ensure an almost uniform velocity over the entire length of the channel, for example, equal to the maximum discharge velocity. In the present application, the terms "section of the distribution channel" and "section of the collection channel" correspond to the section of said channel parallel to the height (Z axis) and perpendicular to the length (X axis) of the meridian panel.

The collecting channels 8 and the distribution channels 4 are complementary in the sense that the distribution channels 4 located immediately above the bed N are associated with the collecting channels 8 located immediately below the bed N. The stream leaving the collection channel 8 is then sent to the distribution channel of bed N +1 by means of a dedicated peripheral duct 10 (as shown in figure 2).

Figure 2 shows the plate N supporting the adsorbent bed N and divided into radial panels 12, these radial panels 12 being parallel and continuous to each other so as to ensure complete coverage of the cross section of the plate N (i.e. XY plane). Fig. 2 also shows the entry point 14 of the fluid to the distribution channel 4 via the exit point 13 of the collection channel 8.

The collection via the peripheral ducts 10 remains separate from each other. Each peripheral duct 10 connects the exit point 13 of the collection channel 8 of a radial panel 12 exclusively to the entry point 14 of the distribution channel 4 of the same radial panel 12. The term "exclusively connected" means that each peripheral duct 10 connected to the collecting channels 8 and to the distribution channels 4 of a given radial panel is not connected to the collecting channels 8 and/or to the distribution channels 4 of another radial panel. It is understood that the peripheral conduit 10 may comprise injection and extraction points 9 outside the column, in particular for the injection of raw materials or solvents or for the extraction of the raffinate or extract. According to one or more embodiments, the plate n is preferably organized as a meridian panel of constant height.

According to one or more embodiments, the flow rate of the distribution channels 4 is adjusted to have the same velocity within the adsorbent bed 6.

According to one or more embodiments, each peripheral duct 10 follows approximately the cylindrical periphery of the tower so as to connect the exit point 13 of the collection channel 8 of the radial panel 12 to the entry point 14 of the distribution channel 4 of the radial panel 12.

According to one or more embodiments, the peripheral duct 10 is dimensioned so that the maximum discharge velocity does not exceed a certain maximum velocity, which is generally less than or equal to 6 m/s and generally between 4 m/s and 6 m/s (for example, for vibration reasons). According to one or more embodiments, the maximum discharge velocity of the fluid in the peripheral duct (10) is between 3 m/s and 5 m/s.

The "network" residence time is referred to in order to indicate the residence time of particles or molecules of the fluid in the peripheral duct 10 from the exit point 13 of the collection channel 8 to the entry point 14 of the distribution channel 4.

The external network of plates n is formed by a number of peripheral ducts 10 equal to the number of radial panels 12 of the plates n. The external network makes it possible to ensure the same residence time for all the particles or molecules of the fluid between the collection and distribution points of the plate n.

According to one or more embodiments, the peripheral conduits 10 of the external network are designed to operate with the same residence time.

It is possible to distinguish between:

the collection side network residence time, which is the residence time of the particles or molecules of the fluid from their exit point 13 from any radial panel from the tower to the injection and extraction point 9,

distribution side network residence time, which is the residence time of particles or molecules of the fluid from the injection and extraction point 9 to their entry point into the tower towards any meridian panel 14.

According to one or more embodiments, the residence time of the external network within the peripheral duct 10 from the exit point 13 to the injection or extraction point 9 is the same, and the residence time of the external network within the peripheral duct 10 from the injection or extraction point 9 to the entry point 14 is the same.

According to one or more embodiments, the length of the peripheral ducts 10 of the external network is variable, so as to allow the same residence time of the particles or molecules of the fluid passing through them. According to one or more embodiments, the peripheral ducts 10 are substantially horizontal and located at the same level (same height) of the tower, optionally with different lengths. According to one or more embodiments, the peripheral catheter 10 comprises a vertical portion making it possible to obtain a desired catheter length. Advantageously, the distribution and collection device is more compact.

According to one or more embodiments, the entry points 14 of the radial panels 12 are generated by means of 1 to 6 entry points. According to one or more embodiments, the exit points 13 of the radial panel 12 are generated by means of 1 to 6 exit points.

The invention also relates to a method of using the distribution and collection device according to the first aspect, in which method a portion of the effluent from the adsorbent bed N enters the collection channels of the radial panel of the plate N, then enters the peripheral ducts connecting only the collection channels of the radial panel to the distribution channels, then enters the distribution channels, and then enters the adsorbent bed N + 1. The process according to the invention is particularly suitable for separating xylenes in a simulated moving bed operating with a number of beds comprised between 4 and 24, and preferentially between 8 and 12.

Examples of the invention

A simulated moving bed adsorption unit (or adsorber) of 10 meters diameter comprises a plate divided into 6 radial panels and is supplied according to the principles of the invention presented in fig. 1. Each bed has a height of 0.77 m.

Simulations carried out with the digital fluid dynamics software FLUENT18.0 show that: the compensation principle of the dwell time between the entry point 14 and the exit point 13 operates correctly. This satisfactory operation is illustrated by fig. 3.

Fig. 3 is a visualization produced by the digital simulation. It is a cross-sectional view of the adsorbent bed N positioned between the distribution channel 4 and the collection channel 8 along a cross-sectional plane similar to that of fig. 1. The entry point 14 of the distribution channel 4 is at the upper left edge. The adsorbent bed 6 is the region between the upper and lower grids 5, 7 depicted by dotted lines. The exit point 13 of the collecting channel 8 is at the lower right edge. The distribution channels 4 of the adsorbent bed 6 have a height of 19 cm at the highest point, i.e. at the entry point 14 of the fluid. The height of the channel then decreases linearly with distance from the entry point 14. In this example, the collection channels 8 of the adsorbent bed 6 are strictly symmetrical to the distribution channels 4. It has a height which increases from the left side to an exit point 13 positioned on the right side of the collecting channel 8.

Fig. 3 also shows a mapping of residence time (or internal mean residence time, i.e. the time elapsed for a predetermined particle or molecule of fluid from the entry point 14 to the exit point 13) at any point of the overall system comprising the distribution channel 4, adsorbent bed 6 and collection channel 8.

The grid of zones a to O indicated on the right in fig. 3 refers to the average internal residence time of the fluid in the bed in seconds and indicates the change in total residence time between about 1.40 seconds indicated by zone a and about 28.3 seconds indicated by zone O. Thus, the particles or molecules of the fluid entering the distribution channel 4 at the entry point 14 have a residence time of approximately 1 second. The residence time of the particles or molecules of the fluid when they leave the collecting channel 8 at the lower right at the exit point 13 is about 28 seconds.

In the bed, the equivalent dwell timeline (line of equal dwell time) is not horizontal. On the same vertical side within the bed, the particles or molecules of the fluid re-entering the bed close to the column inlet on the left side have an extremely short residence time in the distribution zone and therefore a still higher total residence time than the particles re-entering the bed on the right side, which has a longer residence time in the distribution channel. However, the residence time in the bed is the same for all particles or molecules of the fluid.

Simulations have shown that at the outlet the residence time differences occurring in the distribution channel 4 have been compensated by compensating them with the residence time variations in the collection channel 8. The residence time profile is almost perpendicular to the flow direction in the outlet and inlet channels.

The calculation shows about 2 s²Equivalent to a theoretical plate equivalent height of about 2 mm. This is an excellent result in terms of uniformity of residence time.

About one centimeter of HETP (theoretical plate equivalent height) specific to adsorption unit technology was found in Augier et al, 2008.

Reference may be made to page 473 of the cited paper, fig. 9, which shows HETP for various superficial velocities of liquid within the bed. A review of the curves corresponding to the two configurations of the different techniques in the absence of adsorption. The estimate is between 12 cm and 20 cm.

The present invention therefore concerns gains with a ratio of 5 to 10 which can be attributed to the dispersion of the fluid dynamics, which gains are known to the skilled person to directly affect the performance of the process.