RU2576431C1 - System and method of recovering products using simulated moving bed adsorption - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: feedstock stream and desorbent stream are fed into two different ports through two different feed lines along an adsorptive separation chamber with multiple layers. The chamber comprises a given number of spaced-apart ports with corresponding feed lines, linked through a fluid medium with each other to feed and remove the fluid medium into and out of the adsorptive separation chamber. The extract stream and raffinate stream are collected through two different feed lines. The residual fluid medium is flushed in the intermediate feed line of the purification zone between the raw material feed line and the extract feed line in the direction from the adsorptive separation chamber to remove at least a part of the residual fluid medium from the intermediate feed line. The residual fluid medium flushed from the intermediate feed line is fed into another feed line.

EFFECT: high output and purity of the product, reduced amount of the fluid medium for flushing, high efficiency and low power consumption.

11 cl, 13 dwg

Description

Priority Statement

This application claims priority to provisional patent applications US No. 61/570944 and 61/570947, which were filed December 15, 2011

FIELD OF THE INVENTION

An object of the invention relates to a method for adsorptively separating a preferably adsorbed component from a feed stream. More specifically, the invention relates to a method for the continuous adsorption separation of aromatic hydrocarbons in a simulated countercurrent.

State of the art

Paraxylene and metaxylene are important raw materials in the chemical and fiber industries. Terephthalic acid derived from paraxylene is used for the production of polyester fabrics and other products that are currently widely used. Metaxylene is a raw material for the manufacture of many useful products, including insecticides and isophthalic acid. One or a combination of adsorption separation, crystallization and fractional distillation was used to produce these xylene isomers, with adsorption separation capturing most of the market share of the newly built plants for the dominant paraxylene isomer.

Adsorption separation methods are widely described in the literature. For example, a general description of paraxylene recovery was provided on page 70 of the September 1970 edition of Chemical Engineering Progress (Vol.66, No. 9). There is a long history of available reference documents describing useful adsorbents and desorbents, the mechanical parts of a simulated moving bed system, including rotary valves for distributing fluid flows, the internal structure of absorption chambers and control systems. The principle of using a simulated moving bed to continuously separate components of a fluid mixture as a result of contact with a solid absorber is described in US 2,958,589. US 3,976,720 uses the principle of a simulated moving bed to extract paraxylene from a feed stream containing C ₈ aromatics, and in US 4326092 recovery of metaxylene from a stream of C ₈ aromatic hydrocarbons.

In adsorption separation plants treating C ₈ aromatic hydrocarbons _{, a} simulated movement in countercurrent adsorbent and incoming material flow is usually used. Such simulation is performed using established commercial technology in which the adsorbent is held in place in one or more cylindrical chambers with adsorbent, and the positions in which the flows included in the method enter and exit the chambers are slowly shifted along the length of the layers. A typical adsorption separation unit is shown in FIG. 8 and includes at least four streams (starting material, desorbent, extract and raffinate) used in this procedure, and the location at which the feed and desorbent feed streams enter the chamber and the extract and raffinate streams exit cameras are simultaneously shifted in one direction at set intervals. Each shift in the location of the transmission points adds or removes fluid to or from different layers in the chamber. Usually, to simulate the movement in countercurrent adsorbent relative to the fluid flow in the chamber, the flows are shifted in the general direction of the fluid flow, i.e. in the downstream direction, within the chamber, to simulate the movement of the solid adsorbent in the opposite direction, i.e. in the upward direction downstream. The lines at these transfer points are reused as each stream enters or leaves the corresponding layer, and each line therefore carries one of the four processing streams during a particular point in the cycle.

It is recognized in the art that the presence of residual compounds in transmission lines can have a negative effect on a simulated moving bed method. US 3,201,491; US 5,750,820; US 5884777; US 6004518 and US 6149874 describe washing the line used to feed the feed stream into the adsorbent chamber as a means to increase the purity of the extracted extract or absorption component. This washing eliminates contamination of the extract stream with raffinate components from the feed stream remaining in the line when it is subsequently used to extract the extract stream from the chamber. No. 5,912,395 describes the flushing of a line that has just been used to remove a raffinate stream, to prevent contamination of the starting material with raffinate when this line is used to supply a stream of starting material to an adsorbent chamber. All of these links use flushing of such lines back into the chamber with adsorbent, which increases, thus, the load on the separation inside the chamber. US 7208651 discloses flushing outside the chamber with an adsorbent of the contents of a transmission line that was previously used to remove the raffinate stream with one or both of the feed mixture and material withdrawn from the adsorption zone. The residual raffinate in the transfer line is washed in order to attract the raffinate stream as feed to the raffinate column. US 6149874 discloses flushing residual feed from a common compartment of a fluid distribution conduit to an amplification circuit.

In one of the previous typical systems, up to three washes were used to remove residual fluid remaining in the transmission lines. The primary flush displaced the residual extract from the transfer line that had just been used to remove the extract stream with the fluid from the desorption zone of the chamber immediately below the desorbent stream, and it was directed through a rotary valve to the transfer line that was just used to inject the feed stream. Since the volumes in the transmission lines were equal, the fluid of the extract together with the desorbent displaced the residual source material, which was previously in the transmission line, into the adsorbent chamber, directly above the current position of the source material stream so that the residual stream could be separated from the source material stream in the adsorption separation chamber, and to prevent contamination of the extract stream with a residual stream that remains in the transmission line when the extract stream is subsequently shifted to the transmission line, which that was previously occupied by the flow of source material. In addition, the residual extract from the primary wash, used to replace the feed source remaining in the transmission line, is subsequently collected using an extract stream to increase the yield of the extract product.

A typical system sometimes includes a secondary flush. Secondary flushing uses flushing with a fluid, usually a desorbent, through a transfer line and into a chamber immediately below the extract line. Secondary flushing provided a “flush” of such a transfer line with a desorbent to minimize the amount of contaminants including raffinate, starting material and other components that may remain in the transfer line after the initial washing so that these materials were not removed from the transfer line with the extract. Since such a transmission line was previously washed with desorbent and extract during the primary washing, secondary washing was commonly used in applications that require high purity extract. Secondary washing could push the material of the extract and desorbent, previously in the transmission line, back to the adsorption separation chamber. Secondary washing is an optional washing used to satisfy the high purity requirements of the extract product.

Some systems also used tertiary flushing. Tertiary flushing included flushing the transmission line previously occupied by a stream of selected raffinate. Tertiary flushing is used to remove residual raffinate from the transmission line, to limit the injection of this raffinate back into the adsorbent chamber with the source material during the subsequent supply of the feed stream to the transfer line. Since the raffinate stream is depleted in relation to the desired extract component, tertiary washing was performed so that residual raffinate was not injected back into the adsorption separation chamber, which would otherwise increase separation requirements to remove such additional raffinate material. Tertiary flushing was performed by flushing the transmission line away from the adsorption separation chamber using fluid from the port of the chamber located next to the transmission line.

SUMMARY OF THE INVENTION

In accordance with various approaches, a method is provided for separating components in a feed stream using simulated countercurrent adsorption separation. The method includes: supplying a feed stream and a desorbent stream to two different ports through two different respective transmission lines along a multiple-layer adsorption separation chamber. The feed stream has at least one preferably adsorbed component and at least one non-preferred adsorbed component. The adsorption separation chamber in a plurality of layers has a plurality of layers that are serially connected in fluid communication and contains a predetermined number of interconnected ports with respective transmission lines in fluid communication with each other for introducing and removing fluid into and out of the adsorption separation chamber . The method also includes selecting and isolating the extract stream and the raffinate stream through two different ports of the adsorption separation chamber with multiple layers through two different respective transmission lines. The method in accordance with this approach includes flushing the residual fluid located in the intermediate line of the purification zone, defined as the area of the adsorption separation chamber between the transmission line of the feed stream and the transmission line of the extract stream in the direction from the adsorption separation chamber, to remove at least a portion of the residual fluid from the intermediate transmission line. The method also includes directing the residual fluid flushed from the intermediate transmission line to another transmission line, which is not a transmission line of the cleaning zone, to restrict the flow of residual fluid to the cleaning zone.

According to one approach, the residual fluid is combined with the feed stream and introduced into the adsorption separation chamber through a feed line of the feed material so that the residual fluid can be separated in the adsorption separation chamber.

According to another approach, a method is provided for separating components in a feed stream comprising at least one preferably adsorbable component and at least one non-preferred adsorbent component, by simulating countercurrent adsorption separation, which comprises introducing a feed stream to the port of the adsorbent chamber with a plurality of layers containing a plurality of ports with corresponding transmission lines through a transmission line in fluid communication with the port. The method also includes flushing the residual starting material from the transmission line into the adsorption separation chamber such that the washing fluid fills the transmission line with the washing fluid. The method, in accordance with such an approach, further includes flushing the residual fluid to flush away from the adsorption separation chamber, using fluid from the cleaning zone of the adsorption separation chamber located adjacent to the port to fill the transmission line with the fluid of the cleaning zone. The method also includes directing the washed fluid of the residual starting material to another area of the adsorption separation chamber, which is not located between the current positions of the starting material stream and the extract stream, in order to limit the fluid of the residual starting material from contamination by the flow of fluid in the cleaning zone. The method further includes extracting the extract stream from the adsorption separation chamber through the transfer line together with the fluid of the purification zone to reduce the amount of the non-preferred adsorbed component recovered with the extract stream.

According to another approach, a method is provided for separating components in a feed stream using simulated countercurrent adsorption separation. The method includes feeding a feed stream and a desorbent stream to two different ports through two corresponding different transmission lines along a multiple-layer adsorption separation chamber. The feed stream has at least one preferably adsorbed component and at least one non-preferred adsorbed component. A multi-layer adsorption separation chamber has a plurality of layers that are connected in series and in fluid communication and contain a predetermined number of spaced apart ports with respective transmission lines communicating with the fluid to and from each other to enter and remove fluid into and out of the chamber adsorption separation. The method also includes extracting the extract stream and the raffinate stream through two different ports of the adsorption separation chamber with multiple layers through two different respective transmission lines. The method, in accordance with one aspect, includes flushing the residual fluid in an intermediate line of the purification zone between the transmission line of the feed stream and the transmission line of the extract stream away from the adsorption separation chamber to remove at least a portion of the residual fluid from intermediate transmission line. The method also includes directing the residual fluid stream washed from the intermediate transmission line to another intermediate transmission line in the cleaning zone to flush the residual fluid from the other transmission line to the cleaning zone to separate the preferably adsorbed component from the non-preferably adsorbed component present in the residual fluid of another transmission line.

According to one approach, another intermediate transmission line is located between the intermediate transmission line and the feed stream so that the residual fluid enters a portion of the treatment zone adjacent to the feed stream.

According to another approach, a method is provided for separating components in a feed stream comprising at least one preferably adsorbed component and at least one non-preferred adsorbent component by simulating counter-adsorption separation, which includes introducing a feed stream into a port multi-layer adsorption separation chambers containing a plurality of ports with corresponding transmission lines through a fluid communication line this port. The method also includes flushing the residual fluid in the transmission line into a cleaning zone of the adsorption separation chamber between the external transmission lines currently occupied by the feed stream and the extract stream through the port of the transmission line with the flushing fluid. The method, in accordance with this approach, further includes flushing the residual fluid for flushing in the transmission line away from the adsorption separation chamber using the fluid of the cleaning zone, taken through the corresponding port from the cleaning zone, to fill the transmission line with the fluid of the cleaning zone . The method also includes directing at least a portion of the residual flushing fluid obtained by flushing the transmission line to a subsequent transmission line of the cleaning zone of the adsorption separation chamber to provide a flushing fluid to flush the residual fluid of the starting material from the subsequent transmission line to adsorption separation chamber. In addition, the method includes extracting the extract stream from the adsorption separation chamber through the transfer line together with the residual fluid of the purification zone to the transfer line to reduce the amount of non-preferred adsorbed component recovered with the extract stream.

Brief Description of the Drawings

In FIG. 1 shows a simplified diagram of a simulated moving bed absorption method in accordance with various embodiments of the invention;

in FIG. 2 shows a simplified diagram of a simulated moving bed absorption method in accordance with various embodiments of the invention;

in FIG. 3 shows a simplified diagram of a simulated moving bed absorption method in accordance with various embodiments of the invention;

in FIG. 4 shows a simplified diagram of a simulated moving bed absorption method in accordance with various embodiments of the invention;

in FIG. 5 shows a simplified diagram of a simulated moving bed absorption method in accordance with various embodiments of the invention;

in FIG. 6 shows a simplified diagram of a simulated moving layer absorption method in accordance with various embodiments of the invention;

in FIG. 7 shows a simplified diagram of a simulated moving bed absorption method in accordance with various embodiments of the invention;

in FIG. 8 is a diagram of a fluid composition within a simulated moving bed of an adsorption separation chamber in accordance with various embodiments of the invention;

in FIG. 9 is a perspective view of a rotary valve in accordance with various embodiments of the invention;

in FIG. 10-12 are graphs illustrating the volumetric flow rate of a fluid through transmission lines in accordance with various embodiments of the invention; and

in FIG. 13 shows a simplified diagram of a simulated moving bed absorption method of the prior art.

For specialists in the art it will be clear that the elements in the drawings are presented for simplicity and clarity and were not necessarily drawn to scale. For example, the dimensions and / or relative position of some of the elements in the drawings may be exaggerated relative to other elements in order to help improve understanding of various embodiments of the present invention. In addition, common but well-distributed elements that are useful or necessary in a commercially feasible embodiment are often not presented in order to obtain a less cluttered appearance of these various embodiments of the present invention. In addition, it should be understood that certain actions and / or steps can be described in a specific order of their execution, while for a person skilled in the art it will be understood that such a specific description with respect to the sequence is not actually required. It should also be understood that the terms and expressions used here have the usual technical meaning, in the sense that these terms and expressions are understood by those skilled in the art, such as those mentioned above, unless different specific meanings have been formulated here differently.

DETAILED DESCRIPTION OF THE INVENTION

Adsorption separation is used to extract various hydrocarbons and other chemical products. Chemical separation using the approach that has been disclosed involves the separation of mixtures of aromatic hydrocarbons into specific aromatic isomers linear from non-linear aliphatic and olefinic hydrocarbons, or the separation of paraffins or aromatic hydrocarbons from a mixture of feed material containing both aromatic hydrocarbons and paraffins, chiral compounds for use in pharmaceuticals and pure chemicals, oxygenates such as alcohols and esters, and carbohydrates such as to sugar. Aromatic hydrocarbon separations include mixtures of dialkyl substituted monocyclic aromatic substances and dimethylnaphthalenes. The main commercial application, which forms the focus of the previously presented links and the following description of the present invention, without limiting this, is the extraction of paraxylene and / or methaxylene from mixtures of C ₈ aromatic hydrocarbons in accordance with the typical high purity requirements for these products. Such C ₈ aromatic hydrocarbons are usually obtained from the aromatic complex by catalytic reforming of ligroin followed by extraction and fractionation, or transalkylation, or isomerization of streams enriched in aromatic hydrocarbons in such complexes; C ₈ aromatic hydrocarbons typically contain a mixture of xylene and ethylbenzene isomers. The treatment of C ₈ aromatic hydrocarbons using simulated absorption of a moving bed is usually aimed at recovering high-purity paraxylene or high-purity methaxylene; high purity is usually defined as at least 99.5% of the mass. the desired product, and preferably at least 99.7% of the mass. It should be understood that while the following detailed description of the invention focuses on the extraction of high purity paraxylene from a mixture of xylene and ethylbenzene streams, the invention is not limited to this and is also applicable for separating other components from a stream containing two or more components. The term “preferably adsorbed component” as used herein refers to a component or components of a feed stream that is adsorbed more preferably than one or more non-preferred adsorbable feed components.

The invention is commonly used in an adsorption separation method in which countercurrent adsorbent and surrounding fluid are simulated, as described above, but can also be used in practice in a continuous parallel flow method, as disclosed in UA 4402832 and US 4,478,721. Functions and The properties of adsorbents and desorbents in the chromatographic separation of fluid components are well known, and reference can be made to US 4,642,397, which is presented here to further describe these basic adsorption properties. A backflow moving bed system or a backflow simulated moving bed system has much greater separation efficiency for such separation than fixed bed systems because adsorption and desorption operations continuously occur in the feed stream and provide continuous production of extract and raffinate. A full explanation of simulated moving bed methods is provided in the adsorption separation section of the Kirk-Othmer Encyclopedia of Chemical Technology publication on page 563.

In FIG. 1 is a schematic diagram of a simulated moving bed adsorption method in accordance with one aspect. In the method, the raw material stream 5 is in series contact with the adsorbent contained in the vessels and the desorbent stream 10 to separate the extract stream 15 and the raffinate stream 20. In a flow system with a simulated moving bed in countercurrent, the sequential shift of many points of the liquid source material and product access points or ports 25 down the adsorption chamber 100 and 105 simulate the upward movement of the adsorbent contained in this chamber. The adsorbent in a simulated moving bed adsorption method is contained in a plurality of layers in one or more vessels or chambers; two chambers 100 and 105 arranged in series are shown in FIG. 1, although one camera 902 may be used, as shown in FIG. 13, or another number of cameras arranged in series. Each vessel 100 and 105 contains many layers of adsorbent in the treatment spaces. Each vessel has a plurality of ports 25 related to a plurality of adsorbent layers, and the position of the feed stream 5, desorbent stream 10, extract stream 15 and raffinate stream 20 is shifted along port 25 to simulate the movement of the adsorbent layer. A circulating liquid containing desorbent, extract and raffinate is circulated through the chambers using pumps 110 and 115, respectively. Circulating fluid flow control systems are described in US 5,595,665, but the specific details of such systems are not essential to the present invention. A valve type 300 valve with a rotary disk, in accordance with the example presented in US 3040777 and US 3422848, affects the shift of flows along the chamber of the adsorbent to simulate the flow in counterflow. Although a rotary disk valve 300 is described herein, other systems and devices for shifting flows along the adsorbent chamber may also be provided here, including systems that use a plurality of valves to control flow for flows into and out of the adsorbent chamber 100 and / or 105, in as an example described in US 6149874.

In FIG. 9 is a simplified diagram showing an exploded view of parts of an exemplary rotary valve 300 for use in an adsorption separation system and method. The base plate 474 includes a plurality of ports 476. The number of ports 476 is equal to the total number of transmission lines in the camera (s). The base plate 474 also includes a plurality of tracks 478. The number of tracks 478 is equal to the total number of inlet, outlet, and washing lines for the adsorption separation unit (not shown in FIG. 9). In the total number of input, output, and flushing lines, each is in fluid communication with a dedicated path 478. Intersection lines 470 place a given path 478 so that it is in fluid communication with a given port 476. In one example, the total number of inputs includes the input of the starting material and the input of the desorbent, the total number of outputs includes the output of the extract and the output of the raffinate, and the washing lines include one to four washing lines. As the rotor 480 rotates, as indicated, a fluid communication is established for each track 478 with the next serial port 476 via the intersection line 470. A sealing sheet 472 is also provided.

The various streams involved in the adsorption with a simulated moving bed, as shown in the figures and described further below in relation to various aspects of the invention described herein, can be characterized as follows. A "feed stream" is a mixture containing one or more components of an extract, or preferably adsorbed components, and one or more components of a raffinate, or, preferably, adsorbed components that must be separated in a process. An “extract stream” contains an extract component, typically the desired product, which is more selectively or preferably adsorbed by the adsorbent. A "raffinate stream" contains one or more raffinate components that are less selectively adsorbed or not preferably adsorbed. "Desorbent" refers to a material configured to desorb an extract component that is usually inert with respect to the components of the feed stream and can be easily separated from both the extract and the raffinate, for example by distillation.

The stream of extract 15 and stream 20 of the raffinate from the presented schemes contain desorbent in concentrations relative to the corresponding product of the method from 0% to 100%. The desorbent is usually separated from the raffinate and extract components by conventional fractionation in an appropriate raffinate column 150 and extract column 175, as shown in FIG. 1, and they are re-fed into stream 10 ′ by pump 160 of the bottom fraction of the raffinate column and pump 185 of the bottom fraction of the column of extract to return to the method. In FIG. 1 shows the desorbent as the bottom fraction from the corresponding column, given that the desorbent is heavier than the extract or raffinate; various industrial plants for separating C ₈ aromatic hydrocarbons use either light or heavy desorbents, and thus, in some applications, the desorbent can be separated elsewhere along fractionation columns 150 and 175. The refined product 170 and the product 195 of the extract from the method are removed from the raffinate stream and the stream is isolated in the corresponding columns 150 and 175; the product of the extract from the separation of aromatic hydrocarbons C ₈ usually contains mainly one or both of paraxylene and methaxylene, while the product 170 of the raffinate is predominantly not adsorbed aromatic hydrocarbons C ₈ and ethylbenzene.

The fluid flows, for example, the flows of the feed source material 5, desorbent 10, raffinate 20 and extract 15, entering and leaving the adsorbent chambers 100 and 105 through active points or liquid access ports 25, effectively separate the adsorbent chamber 100 and 105 into separate zones, which move as they shift flows along ports 25. It should be noted that, while most of the description here refers to FIG. 1 and the location of the flows in FIG. 1, in FIG. 1 illustrates only the current location of the streams in one step or in a “snapshot” of the method, since streams usually move downstream at different stages of the cycle. As you perform the shift of the flows downstream, the composition of the fluid and the corresponding zones perform a shift downstream along with them. In one approach, the position of the streams with respect to the access point or port 25 of the adsorption separation chambers 100 and 105 remains generally constant with respect to each other as they synchronously continue further down along port 25. In one example, each stream moves down one port 25 downstream at each stage, and each stream occupies each port 25 at the same time throughout the cycle. In accordance with one example, the threads perform stepwise movement simultaneously to subsequent ports 25, as a result of rotation of the rotary valve 300, and are maintained at a specific port 25 or at a certain stage for a given interval - time for a step. In one approach, there are from 4 to 100 ports 25, from 12 to 48 ports in another approach, and from 20 to 30 ports in another, different approach, and an equal number of corresponding transmission lines. In one example, the adsorption separation camera or cameras 100 and 105 include 24 ports, and each stream is shifted to each of the 24 ports 25 for a full cycle such that each stream occupies each port 25 and its corresponding transmission line during the cycle. In this example, the cycle can be from 20 to 40 minutes in one approach and from 22 to 35 minutes in another approach. In one approach, the time interval for one step is from 30 seconds to two minutes. In another approach, the time interval of one step is from 45 seconds to one minute thirty seconds. In another approach, the time interval of one step is from 50 seconds to one minute and 15 seconds. An example of a typical time interval of one step may be 1 minute.

With this in mind, FIG. 8 is a snapshot of a composite fluid profile in an adsorption separation chamber (for simplicity, a single adsorption separation chamber 100 is shown in FIG. 8), and corresponding zones into which the adsorption separation chamber 100 is divided. An adsorption zone 50 is located between the input stream 5 of the source material and the output stream 20 of the raffinate. In this zone, the input stream 5 is in contact with the adsorbent, the extract component is adsorbed, and the raffinate stream 20 is selected. As shown in the figure, raffinate stream 20 may be sampled at a location where the composition includes raffinate fluid 454 and a small amount, if any, of the extract fluid 450. Immediately upstream of the fluid stream, there is a purification zone 55 defined as an adsorbent between the extract output stream 15 and the feed input 5. In the purification zone 55, the raffinate component is displaced from the non-selective empty volume of the adsorbent and stripped from the pore volume or from the surface of the adsorbent with a shift to this zone by passing part of the material of the extract stream, which leaves the stripping zone 60. The desorption zone 60, in front of the purification zone 55, is defined as an adsorbent between the desorbent stream 10 and the extract stream 15. The desorbent entering this zone displaces the component of the extract that was adsorbed as a result of previous contact with the starting material in the adsorption zone 50. Extract stream 15 may be sampled at the location of chamber 100, which includes extract fluid 450 and a small amount, if any, of raffinate fluid 454. The buffer zone 65 between the outlet of the raffinate stream 20 and the inlet of the desorbent stream 10 prevents contamination of the extract so that part of the desorbent stream enters the buffer zone to displace the raffinate material present in this zone back to the adsorption zone 50. The buffer zone 65 contains a sufficient amount of adsorbent to prevent the passage of the raffinate components to the desorption zone 60 and to contaminate the extract stream 15.

Each of the zones described above is generally obtained by having multiple compartments or “layers” as described in US 2,985,589. The positions of the various described streams are structurally separated from each other by a horizontal fluid collection / distribution grid. Each grid is connected to a transmission line forming a transmission point at which the processed streams enter and exit the adsorbent chamber. This arrangement facilitates the distribution of fluids in the chamber by eliminating the formation of channels and other inefficient elements, prevents convection back mixing of the fluid in the opposite direction to the primary fluid flow, and prevents the adsorbent from migrating through the chamber. Each of the zones described above usually contains many, 2-10 and often 3-8, layers. A typical simulated moving bed adsorption device comprises 24 adsorbent layers.

In FIG. 1, it can be seen that when the transmission line at the access point 25, which is used to transport a particular stream to or from the adsorbent chamber, is left idle at the end of the step, it remains filled with the connections forming this stream until these connections will not be removed from the line by the second flowing stream. In this regard, it should be noted that only active transmission lines, that is, those lines which currently facilitate the flow of fluid through them, are shown in FIG. 1, although intermediate transmission lines are present in each of the ports 25 along the chambers 100 and 105, which facilitate the flow of fluid after shifting the fluid flows to subsequent ports 25. Residual fluid or components left in the now unused transmission line after shifting the flow in the next transmission line, therefore, will either be selected from the method as the initial part of the processing stream removed from the method, or will be forcibly transferred to the absorption chamber when the transmission line transfers the stream to the adsorb chamber ta. In FIG. 13 illustrates a previous system showing unused transmission lines represented by dashed lines and transmission lines currently occupied by a stream, such as stream 920, indicated by solid lines extending from the ports of the adsorption separation chamber 902.

Returning to FIG. 1, as described above, the presence of residual fluid in the transmission lines can adversely affect the performance of the simulated moving bed adsorption separation method. For example, the residual raffinate in the transmission line, which was previously used to remove the raffinate stream 20 from the adsorption chamber, can be washed into the adsorption chamber 105 by the feed material stream 5 when it is shifted to this transmission line in a subsequent step. Similarly, the residual stream in the transmission line that was previously used for the feed material stream 5 to the adsorption chamber can be removed from the transmission line by the extract stream 15 when it is transferred to this transmission line in a subsequent step. Similarly, the residual extract in the transmission line, which was previously used to remove the extract stream from the adsorption chamber, can be washed back into the adsorption chamber 100 with the desorbent stream 10 when it subsequently enters this transmission line.

In accordance with one aspect, the primary flushing of the method and system includes a primary flushing of 30, which flushes the residual stream from the transmission line previously occupied by the feed stream 5 to the adsorption separation chamber 105 and, more specifically, to the cleaning zone 55. An initial flush of 30 may preferably be directed to the transfer line of the cleaning zone 55 next to the transfer line currently occupied by the feed stream 5 to introduce residual feed into the adsorption separation chamber 105 near the feed stream 5 so that the residual source material can be divided in it. In one example, a primary flush of 30 may be directed to the transmission line of the cleaning zone 55, within two transmission lines of the feed stream 5, and, more preferably, to a transfer line located adjacent to the feed stream 5, as shown in FIG. 1. In one approach, a primary flushing at 30 uses a flushing fluid comprising a substantially, preferably adsorbed, desorbent and / or inert components. In other words, the flushing fluid preferably includes a small amount, if any, of the adsorbent component is preferably not adsorbed from the feed stream to limit contamination of the extract stream 15 when this extract stream enters the transfer line during the next step.

The primary flushing of the method and system may include a primary flushing 35 to flush the residual fluid of the extract from the transmission line previously occupied by the extract stream, away from the adsorption chamber. The extract fluid along with the primary wash fluid is then transferred to the primary wash in the 30 transfer line as the wash fluid and is used to wash the remaining feed material from the transfer line previously occupied by the feed stream to the cleaning zone of the adsorption separation chamber 105 as described previously. In one approach, a primary flush of 35 uses fluid from the desorption zone 60 of the chamber 100 to flush the transmission line, which includes mainly a desorbent. Thus, after a primary wash of 35 flushes the residual extract fluid in the transmission line previously occupied by the extract stream 15, a very small amount of the extract fluid remains in the transmission line. Preferably, by combining a primary fluid of 35 with a primary flush of 30, the residual fluid in the transmission line can be used to flush other transmission lines, reducing the total amount of fluid required for processing and increasing the productivity of the process by trapping these fluids, performing the transmission line cleaning assignment described previously. In addition, the pairwise use of the primary wash provides a primary wash fluid of 30, which includes mainly a desorbent and, preferably, an adsorbed component from the fluid of the residual extract. Similarly, this provides a flushing fluid for a primary flush of 30, which includes a very small amount of an optionally adsorbed component. In one example, the washing fluid for a primary washing of 30 includes more than 99% of the mass. desorbent and preferably an adsorbed component. In another example, the washing fluid includes less than 0.005% of the mass. non-preferred adsorbed component (s).

According to one approach, secondary flushing 40 is used to flush residual fluid from the transmission line, which will subsequently be taken up by the extract stream 15, to remove contaminants from the transmission line. Secondary flushing 40 preferably provides improved purity of the extract stream by removing contaminants from the transmission line before the transmission line is used to collect the extract stream 15 through it. Previous systems used flushing from the desorbent in the transfer line and towards the adsorption separation chamber to flush the contents of the transfer line, which is subsequently used to extract the extract stream. Such washing is passed through a transmission line in the direction of the adsorption separation chamber and into the cleaning zone of the adsorption separation chamber to ensure its cleaning.

It was noted that secondary flushing of the systems described above resulted in a reduction in useful yield or energy costs. In particular, since desorbent is used in the secondary wash 40 to flush the residual preferably adsorbed component / fluid desorbent in the transfer line in the adsorption separation chamber, such a transfer line includes almost exclusively the desorbent after the secondary wash. Residual desorbent in such a transmission line is subsequently taken as the initial wave of fluid using the extract stream before removing the extract. The extract stream, including such a wave of residual desorbent, is sent to the extract fractionation column 175, where it is separated into fractions, withdrawn as bottoms, and recycled to the treatment cycle with the desorbent recirculation stream to the first chamber 100. However, in order to to get into the column 175, the wave of residual desorbent in the transmission line at the beginning of the removal of the extract must also be heated before it is fed to the column 175 of the extract for separation into fractions. For example, when paraxylene is separated from the xylene mixture feed stream, the desorbent selected with the extract stream is heated from 150 ° C to 300 ° C, which leads to energy consumption or a decrease in useful product. In other words, since such an initial desorbent flush contains a very small amount, if any, of the required extract product, a substantial supply of energy is needed to increase the temperature of the bottom product of the fractionation column without providing an advantage in terms of increasing the yield of the extract product.

In order to eliminate such energy loss, in accordance with one aspect, the secondary stream 40 flushes the residual fluid of the transmission line 45 away from the adsorption separation chamber 100 in a direction opposite to the previous systems so that the residual desorbent does not accumulate in the transmission line 45. It should be noted that transmission line 45 is used for secondary flushing 40 in the step of FIG. 1, however, during previous or subsequent steps, secondary flushing 40 can be shifted along with the streams and can be used to remove residual fluid from other transmission lines. More specifically, instead of using a desorbent stream to flush the residual fluid from the transmission line 45, which may include, mainly, an adsorbent component and desorbent remaining in the transmission line after an initial washing of 30, a fluid is used from the cleaning zone next to port 45 ′ of the transmission line corresponding to the transmission line for flushing the residual fluid in the direction from the adsorption chamber 100. The secondary wash stream can then be transferred for further processing. In one approach, the secondary flushing is passed through line 40 ′ to line 10 ”of the recirculation of the fluid. The fluid recirculation line 10 ′ may include mainly a desorbent, which is separated into fractionation columns 150 and 175 and returned to the adsorption separation chamber 100, where it is reused in the method. In one approach, the secondary wash stream is passed through line 40 ′ to the bottom portion 155 of the raffinate fractionation column 150, where it is combined with the desorbent separated by the raffinate fractionation column 150, and fed to the reuse fluid line 10 ′ through the bottom raffinate pump 160. In another approach, the secondary wash stream is fed through line 40 ′ to the bottom portion 180 of the extract fractionation column 175, where it is combined with the desorbent separated by the extract fractionation column 175 and sent to the fluid recirculation line 10 ′ through the bottom extract pump 185.

Since such a fluid from the purification zone 55 is similar in composition to the extract stream 15, which will subsequently be taken from the transfer line 45, the residual fluid remaining in the layer line after the modified secondary washing 40 will preferably be similar in composition to the desired extract composition. To this end, in one example, the transmission line 45 is flushed during the secondary flushing 40, within two transmission lines or ports from the transmission line currently occupied by the extract line 15, and more preferably within one transmission line or port from the line the transmission currently occupied by the extract line 15, since the fluid of the purification zone adjacent to the ports located next to the extract transfer line will have a composition most similar to the extract stream 15. In one example, the purification zone fluid has more than 99% desorbent and preferably an adsorbed component. In another example, the purification zone fluid has less than 0.005% of the non-preferred adsorbed component (s). In addition, when a primary wash of 30 is used to wash the residual feed stream as described above, the secondary wash 40, in accordance with one approach, is located between the transmission line currently occupied by the extract stream 15 and the transmission line currently occupied by the primary flushing at 30, so that the transmission line 45 is mainly filled with residual fluid from the primary flushing at 30 instead of the feed stream 5. This approach preferably reduces the degree of contamination of the extract stream 15 with residual starting material.

Further, in one approach, the fluid from the transfer line 45, which will subsequently be taken with the extract stream 15, will be transferred to the extract fractionation column 175 for separation by distillation. The residual fluid in the transfer line 45, which is transferred with the extract stream to the fractionation column 175, is heated in the extract fractionation column 175. Since such residual fluid is similar in composition to the extract stream 15, fractionation of this fluid results in increased recovery of the desired extract product 195. Thus, unlike previous systems, the fluid remaining in line 45 from the transmission after secondary washing 40, which is subsequently taken with the extract stream 15 and transferred to the extract fractionation column 175, does not lead to unnecessary performance losses, since distillation of such a fluid leads to an additional yield of the desired secreted product 195, compared with the use of primary desorbent.

In accordance with another aspect of FIG. 2, extract stream 15 may be taken through a transmission line during the previously described step. With this approach, the extract stream 15 is taken along with the residual fluid remaining in the transmission line so that the extract stream flushes the residual fluid from the transmission line. The source wave of the extract stream, including at least a portion of the residual fluid, is routed through the transmission line to the first destination. The subsequent portion of the extract stream is then sent through a transmission line to a second destination. At least a portion of the residual fluid in the transmission line is directed to the first destination. In one example, at least 90% of the residual fluid is directed to the first destination. In another example, at least 95% of the residual fluid is directed to the first destination. In one approach, the second destination is the inlet 190 of the extract fractionation column 175. The first destination may be a recycle line 10 ′ intended to re-route the extract stream and part of the residual fluid into the adsorption separation chamber 100 in the processing cycle.

As shown in FIG. 2, a primary flush of 30 can be used to flush the residual fluid of the starting material remaining in the transmission line previously occupied by the feed 5 to the adsorption separation chamber 105, as described above, to limit the selection of the residual fluid with the feed with the extraction stream as residual fluid in the transmission line when the extract stream 15 enters the transmission line in a subsequent step. The flushing fluid preferably includes a primary desorbent and / or preferably an adsorbable component and includes a very small amount of a non-preferred adsorbent component such that the residual fluid remains in the transmission line after the primary flushing of 30 includes a very small amount of a non-preferred adsorbed component. In one approach, the flushing fluid includes less than 1% of the non-preferred adsorbed component, and in another example, includes less than 0.005% of the non-preferred adsorbed component. As described above, the residual extract remaining in the transmission line previously occupied by the extract stream 15 may be washed out of the transmission line by primary washing 35, and the residual extract fluid may be transferred to the primary washing 30 in the transmission line intended for use in as a flushing fluid for the primary flushing at 30. The residual fluid of the extract may be flushed during the primary flushing 35 by draining the fluid from the desorption zone 60 near port 25 that communicates with the primary by transferring the wash 35. In this regard, the residual fluid in the transmission line when the extract stream 15 is shifted onto it may include a primary residual discharge and a wash fluid withdrawn from the desorption zone 60 during the primary wash 35, for example, residual extract and desorbent.

Returning to the additional elements shown in FIG. 2, in accordance with this approach, the extract stream 15 is sampled through a transmission line including the residual fluid, so that the original wave of the extract stream will include the residual fluid that remained in the transmission line before the extract stream 15 arrives. As noted above, such an initial extract stream wave may be fed to the recirculation line 10 ′ to feed it back to the adsorption separation chamber 100. To this end, an initial extract stream wave may be transmitted to a portion 155 of the bottom of the raffinate fractionation column. At a portion 155 of the bottom of the raffinate column, a fluid wave is combined with a fluid exiting the bottom of the raffinate fractionation column 150, which in one example includes a primary desorbent that has been separated in the raffinate fractionation column 150. A pump 160 at the bottom of the raffinate column can be used to direct such a wave of fluid and desorbent back to the adsorption separation chamber 100 through a re-direction line 10 ′ into the cycle. Alternatively, the source wave of the extract stream may be transmitted to part 180 of the bottom fractionation column of the extract. Section 180 of the bottom fractionation column is combined with a fluid exiting the bottom of the extract fractionation column 175, which in one example includes a primary desorbent that has been separated in the extract fractionation column 175. The pump 185 of the lower part of the extraction column can be used to direct such a wave of fluid and desorbent back to the adsorption separation chamber 100 through the recirculation line 10 ′.

Thus, at least a portion of the residual fluid sampled by the extract stream 15 will not be directed into the inlet 190 of the extract fractionation column. Since the residual fluid in the transmission line from the primary fluid 30 will contain a larger percentage of desorbent than the extract stream 15, such excess desorbent will preferably not be separated in the extract fractionation column 175. Since the fluid entering the inlet of the extract fractionation column 190 is heated, if excess desorbent in the residual fluid is supplied to the extract fractionation column 175, it will be heated to the final temperature of the lower part, without providing an additional increase in the emitted product, and thus Thus, leads to excessive energy consumption. Thus, by deflecting the initial wave of the fluid so that excess desorbent is not supplied to the extract fractionation column 175, the amount of energy required to operate the system is reduced.

In accordance with one aspect, the extract stream 15 is withdrawn from the adsorption separation chamber 100 and fed along the transmission line 15 ′. In one approach, a rotary valve 300 is provided such that extract stream 15 is withdrawn through a transmission line and directed to a rotary valve, where it is combined with a single extract transfer line 15 ′, as shown in FIG. 2, although other configurations may be provided herein, including providing a dedicated extract extract line 15 ′ for each transmission line of the adsorption separation chambers 100 and 105. The transfer line 15 ′ may have one extract inlet port line 205 in fluid communication with the inlet portion 190 of the extract fractionation column. The transfer line 15 ′ may have another line 210 of the bottom portion of the column, which is in fluid communication with one or both of the portion 180 of the bottom of the extract column and the portion 155 of the bottom of the raffinate column. A valve 215 may be provided to divert the flow for the extract stream 15 between the extract column inlet line 205 and the lower section of the extract column line 210. Thus, the method includes the steps of: moving the valve 215 to the first position to direct the flow 15 of the initial portion of the extract, comprising at least a portion of the residual fluid through the line 210 of the section of the lower part of the extract column to one of the sections 180 of the lower part of the extract column and a portion 155 of the bottom of the raffinate column. In such an example, the method includes the steps of: transferring the valve 215 to a second position to direct the extract stream 15 through the extract column inlet line 205 and in the direction of the inlet 190 of the extract separation column into parts to separate the extract stream 15 therein.

In accordance with one aspect, an extract stream including at least a portion of the residual fluid flushed from the extract stream transmission line is directed to a first destination, for example, to one or both of the columns of the extract and to sections 180 and 155 of the bottom parts of the raffinate column during the first predetermined time or predetermined period of a step-by-step time interval (when the extract stream occupies the current transmission line). The extract stream is then directed to a second destination, for example, the inlet of the extract fractionation column 175 for a second predetermined time or a predetermined part of the time interval in incremental increments. The first predetermined time can be selected based on the flow rate for the extract stream, to flush a predetermined amount of residual fluid in the transmission line to a second destination or a predetermined amount of fluid to a second destination. In one example, the first predetermined time may be sufficient to direct the fluid volume from 50% to 250% of the volume of the transmission line and with appropriate valve control, and in another example from 80% to 150% of the volume of the transmission line and with appropriate valve control, in the first place destination. In one approach, the second transmission line may be the remainder of the interval with a predetermined step length so that the extract stream 15 is directed into the inlet 190 of the extract column during the residual interval in incremental increments to separate the extract stream 15 in the extract fractionation column 175. A predetermined time can also be selected to direct all or at least part of the residual fluid to the transmission line to the first destination so that the residual fluid will not be supplied to the fractionation column of the extract to save energy. Similarly, a first predetermined volume of extract stream may be directed to a first destination, and a second predetermined volume of extract stream may be directed to a second destination. The first predetermined volume may be such a volume as described above for the first predetermined time. The second predetermined volume may be the residual volume of the extract stream taken through the transmission line during the time step interval. In one example, the first preset line is between 10% and 90% of the interval with step-by-step time determination. The second set time in this example is from 10% to 90% of the interval with a step-by-step set time. In another example, the first set time is from 20% to 40% of the interval with a step-by-step set time. The second set time in this other example is in the range of 60% to 80% of the interval with a step-by-step set time.

In another approach, the method includes monitoring the composition of the extract stream, including any residual fluid, to determine the amount or percentage of the component in the composition. For example, the component may be one of a preferably absorbable component, a desorbent component, or an optionally adsorbed component. The method, in accordance with this approach, includes the steps of: directing the extract stream 15 and any residual fluid to the first destination when the composition includes the component at a first predetermined level, and directing the extract stream 15 to the second destination when the composition includes a component at a second predetermined level. For example, the method may include operations: monitoring the composition of the extract stream 15 to determine the amount of desorbent present in the stream. According to this example, the method may include the steps of: directing the flow of extract to the first destination when the amount of desorbent is greater than a threshold level, and directing the flow of extract to the second destination when the amount of desorbent is below a predetermined threshold level. Thus, the amount of desorbent transferred to the inlet 190 of the extract fractionation column can be reduced.

Preferably, in accordance with this approach, secondary flushing 40 can be excluded from previous systems. Thus, processing can only be used using one less active transmission line. For example, in processing, only six or seven transmission lines can be used instead of seven or eight transmission lines, as was required in previous systems. In one approach, the method may use a rotary valve 300 with only six or seven paths, including paths for extract, refining, starting material and desorbent streams, and also primary washing 35, primary washing 30 and, if necessary, a third washing 46. This approach preferably allows you to modify the existing adsorption separation system with six and seven valves with rotating tracks to use the invention in accordance with this approach.

Returning now to FIG. 3, an adsorption separation system and method in accordance with another aspect of the invention is explained. In accordance with this aspect, the raffinate stream 20 can be sampled through the transmission line during the step described above. With this approach, the raffinate stream 20 is withdrawn along with the residual fluid remaining in the transmission line of the raffinate stream so that the raffinate stream 20 flushes the residual fluid from the transmission line. This aspect is similar to that described above and is presented in FIG. 2 in that the initial wave of the raffinate stream is directed to the first destination. The next portion of the raffinate stream is then sent to a second destination. At least a portion of the residual fluid in the transmission line is directed to the first destination. In one example, at least 90% of the residual fluid is directed to the first destination. In another example, at least 95% of the residual fluid is directed to the first destination. In one aspect, the second destination is an inlet 165 of a raffinate fractionation column 150. The first destination may be a recycle line 10 ′ intended for reuse of the raffinate stream and part of the residual fluid with their supply to the adsorption separation chamber 100. In this regard, by re-circulating a portion of the fluid back to the adsorption separation chamber 100, the amount of fluid treated with the raffinate fractionation column 150.

As shown in FIG. 3, in one approach, a transmission line occupied by raffinate stream 20 was previously occupied by desorbent stream 10. In this regard, the transmission line may include substantially the residual desorbent fluid when the raffinate stream enters the transmission line in a subsequent step.

Returning more specifically to FIG. 3, in accordance with this aspect, the raffinate stream 20 is sampled through a transmission line including the residual fluid, so that the original wave of the raffinate stream will include the residual fluid that remained in the transmission line before the arrival of the raffinate stream 20. As mentioned above, this initial raffinate stream wave may be transmitted to the recycle line 10 ′ for directing to recycle to the adsorption separation chamber 100. To this end, similarly to the approach described previously with reference to FIG. 2, the initial wave of the raffinate stream 20 can be fed to the bottom portion 155 of the raffinate fractionation column. In the lower portion 155 of the raffinate column, a fluid wave is combined with a fluid exiting the bottom of the raffinate fractionation column 150, which in one example includes mainly desorbent that has been separated in the raffinate fractionation column 150. The pump 160 of the bottom of the raffinate column can be used to direct this wave of fluid and desorbent back to the adsorption separation chamber 100 through a recycle line 10 ′. Alternatively, the initial wave of the raffinate stream 20 may be transmitted to the bottom 180 of the extract fractionation column. In the lower part of the extract column 180, a fluid wave is combined with the fluid present in the lower part of the extract fractionation column 175, which in one example includes mainly desorbent, which was separated in the extract fractionation column 175. Similarly, the pump bottom 185 of the column of the extract can be used to direct this wave of fluid and desorbent back to the adsorption separation chamber 100 through a recycle line 10 ′.

Thus, at least a portion of the residual fluid sampled from the raffinate stream 20 is not directed into the inlet 165 of the raffinate fractionation column. Since the residual fluid in the transmission line will contain a greater percentage of desorbent than the fluid of the raffinate stream, such excess desorbent is preferably not directed and does not separate in the raffinate fractionation column 150. Since the fluid entering the inlet 165 of the raffinate fractionation column is heated in the column, if excess desorbent in the residual fluid is supplied to the raffinate fractionation column 150, it would be heated without providing an additional yield of the extract product, and thus, to additional energy costs. Thus, by redirecting the initial wave of the fluid so that excess desorbent is not supplied to the raffinate fractionation column 150, the amount of energy required to operate the system will be reduced.

In one approach, the raffinate stream 20 is withdrawn from the adsorption separation chamber 100 and fed along the transmission line 20 ′. In one approach, a rotary valve 300 is provided to select a raffinate stream 20 through a transmission line and direct it to a rotary valve 300, where it is combined with a single raffinate transfer line 20 ′, as shown in FIG. 3, although other configurations are discussed herein, including providing a dedicated raffinate transfer line 20 ′ for each transmission line of the adsorption separation chambers 100 and 105. The transfer line 20 ′ may have one raffinate inlet line 305 in fluid communication with the inlet 165 of the raffinate fractionation column. The transfer line 20 'may have another lower line 310, in fluid communication with one or both lower parts of the extract column 180 and the lower part of the raffinate column 155. A valve 315 may be provided to switch the flow for the raffinate stream 20 between the raffinate column inlet line 305 and the bottom portion of the raffinate column line 310. Thus, the method includes the steps of: moving the valve 315 to the first position to direct the initial portion of the raffinate stream 20, comprising at least a portion of the residual fluid through the line 310 of the bottom of the raffinate column into one of the lower parts 180 of the extract column and the lower parts 155 raffinate columns. In this example, the method includes the following: moving the valve 315 to a second position to direct the raffinate stream 20 through the inlet line of the raffinate column 305 and in the direction of the inlet 165 of the raffinate fractionation column to separate the raffinate stream 20 therein.

In one aspect, the raffinate stream 20, comprising at least a portion of the residual fluid flushed from the transmission line by the raffinate stream, is directed to a first destination, for example, one or both of the lower portions 180 and 155 of the extract column and the raffinate column for the first predetermined line or a predetermined part of the step time interval (when the raffinate stream occupies the current transmission line), the raffinate stream is then sent to a second destination, for example, to the inlet 165 of the raffinate fractionation column for the second predetermined of time or for a predetermined range of step interval. The first predetermined time may be selected based on the flow rate for the raffinate stream 20 to flush a predetermined amount of residual fluid in the transmission line to a second destination or a predetermined amount of total fluid to a second destination. In one example, the first predetermined time may be sufficient to direct a fluid volume of 50% to 250% of the volume of the transmission line and associated valves, and in another example, 80% to 150% of the volume of the transmission line and associated valves to the first destination . In one approach, the second predetermined time may be the remainder of the step time interval so that the raffinate stream 20 is directed to the inlet 165 of the raffinate column during the remainder of the step time interval to separate the raffinate stream 20 in the raffinate fractionation column 150. The predetermined time can also be selected with its other values to direct all or at least part of the residual fluid to the transmission line to the first destination so that the residual fluid will not be introduced into the raffinate fractionation column 150 to provide savings energy. In one example, the first predetermined time is in the range of 10% to 90% of the time interval of the step. The second set time in this example is in the range of 10% to 90% of the time interval of the step. In one example, the first predetermined time is in the range of 10% to 30% of the time interval of the step. The second set time in this example is in the range of 70% to 90% of the time interval of the step. Similarly, a first predetermined raffinate stream volume may be directed to a first destination, and a second predetermined raffinate stream volume may be directed to a second destination. The first predetermined volume may have the same percentage of transmission line volume and associated valves as described above for the first predetermined time. The second predetermined volume may be the residual volume of the raffinate stream taken by the transmission line during the time interval of the step.

In another aspect, the method includes: tracking a composition of a raffinate stream 20 including any residual fluid present therein to determine the amount or percentage of a component in the composition. For example, the component may be one of a preferably adsorbed component, a desorbent component, or a non-preferred adsorbed component. The method, in accordance with this approach, includes the following: directing the raffinate stream 20 and any residual fluid to the first destination when the composition includes the component at a first predetermined level, and directing the raffinate stream 20 to the second destination when the composition includes a component at a second predetermined level. For example, the method may include the following: the composition of the raffinate stream is monitored to determine the amount of desorbent present in the stream. According to this example, the method may include: directing the raffinate stream to the first destination when the amount of desorbent is above a threshold level, and directing the raffinate stream to the second destination when the amount of desorbent is below the threshold level. Thus, the amount of desorbent supplied to the inlet 165 of the raffinate fractionation column can be reduced.

Returning to FIG. 4, in accordance with another aspect, the adsorption separation method includes primary washing 405 to flush the residual fluid in the intermediate transmission line of the cleaning zone 55, between the transmission line occupied by the feed stream 5 and the transmission line occupied by the extract stream 15 from the chambers 100 and 105 adsorption separation, to remove at least a portion of the residual fluid from the intermediate transmission line. The method, in accordance with this aspect, further includes: transferring the residual fluid washed from the intermediate transmission line to another transmission line, which is not a transmission line for the cleaning zone 55, to limit the residual fluid flow that is introduced into zone 55 cleaning. Thus, the residual fluid in the intermediate transmission line is not injected back into the purification zone, as in previous systems, where the components of the residual fluid would be separated, but without the advantage of flowing through the entire purification zone 55 before being taken through the extract stream 15 at the top of the zone 55 cleaning.

In one aspect, the residual fluid rinsed by primary washing 405 is transferred to and combined with a feed stream 5, which is fed into the adsorption separation chamber 105 along with feed stream 5 through a feed stream transfer line. Thus, the components of the residual fluid introduced with the feed stream can be separated in the adsorption separation unit while supplying the feed fluid introduced through the feed stream 5. This provides a more complete separation of the components than if the residual fluid was introduced directly into the purification zone 55 through the intermediate transmission line, since the components in the residual fluid can flow through the entire purification zone 55 between the source material stream 5 and the extract stream 15 before being taken through stream 15 of the extract. This approach can increase the purity of the extract stream 15, due to a more complete separation of the components of the residual fluid.

Residual fluid remaining in the intermediate transmission line, which is washed using a primary flush 405, in accordance with one approach, may include residual fluid of the starting material. To this end, the intermediate transmission line could be preoccupied with the feed stream 5, so that the intermediate transmission line includes the residual fluid of the feed when the feed is shifted from there at the end of the step. The residual fluid of the source material can preferably be combined with the stream 5 of the source material and can be injected into the cleaning zone through the transmission line of the stream of the source material and the port, so that the components in the residual fluid of the source material will be separated to the same extent as the components of stream 5 of the source material itself.

Since the pressure in the transmission line of the primary wash 405 may be lower than the pressure in the transmission line of the feed stream, it may be necessary to pump the primary wash fluid into the pump in order to overcome the pressure drop, and for combination with feed stream 5. In this regard, a pump 410 may be provided to pump the primary fluid to flush through the intermediate transmission line and combine it with the feed stream 405. In one approach, the system may include a rotary valve, wherein the primary fluid will be pumped through an intermediate transmission line and a rotary valve 300, where it is combined with the feed stream 5. However, in some transmission lines or ports 25 along the adsorption separation chambers 100 and 105, where two or more adsorption separation chambers 100 and 105 are used, the pressure in the feed stream 5 may be higher than the pressure of the primary wash stream 405, where the primary stream 405 washing is transferred between the transmission line near the lower part of the adsorption separation chambers 100 and 105, for connection with the feed material stream 5 near the upper part of the other of the adsorption separation chambers 100 and 105. At these positions, the residual starting material in the line can generate a wave in the extract stream, since adjacent transmission lines are often in fluid communication with each other during processing using rotary valve 300. Thus, in one approach, pump 410 is located downstream flow from a rotary valve, as shown in FIG. 4 to limit the residual starting material in the intermediate transfer line from backwashing to the extract stream 15 when the streams are located at certain positions along the adsorption separation chambers 100 and 105.

In accordance with one aspect, primary flushing 405 includes the removal of fluid from the cleaning zone 55 of the adsorption separation chamber 100 through port 25 of the transmission line 415. The cleaning zone fluid is taken from a location in the cleaning zone 55 near port 25 and transferred to an intermediate transmission line in order to release residual fluid into the intermediate transmission line at a distance from the adsorption separation chamber 100. Flushing the intermediate transfer line 415 with the cleaning zone fluid preferably fills the fluid transfer line 415, which has a higher concentration of the preferably absorbed component than the non-preferred adsorbed component, to reduce contamination of the extract stream 15 when the extract stream 15 enters the intermediate transfer line 415 in the next step. In one approach, the purification zone material is sampled into the transmission line at a location adjacent to the transmission line currently occupied by the extract stream 15 so that the fluid in the purification zone 55 is sampled in a similar manner to the fluid in the extract stream. In one approach, the purification zone fluid is sampled through port 25 and into the transmission line, within two transmission lines from the transmission line currently occupied by the extract stream 15. In another approach, the purification zone fluid is sampled through port 25 and into an intermediate transmission line of the purification zone 55 located adjacent to the transmission line currently occupied by the extract stream 15. Thus, the composition of the cleaning zone fluid used to flush the intermediate transmission line, which remains in the transmission line after the initial washing, will be similar to the composition of the separated fluid of the stream and may include only a small amount, if any, of non-preferred adsorbed components from the stream source material, which, otherwise, could contaminate the stream 15 of the extract when it enters the intermediate transmission line during the next step. In one example, the selection of fluid from the treatment zone, from the adsorption separation chamber, includes less than 0.5% of an unsuitably adsorbed component. In another example, the material of the cleaning zone used for the initial washing of 405 includes less than 0.005% of the non-preferred adsorbed component. As will be appreciated, in accordance with this aspect, by transferring the primary flush from 405 and combining it with the feed stream 5, one less transmission line may be required compared to the system for transferring the residual fluid from the primary flush to another intermediate transmission line.

A method and system for adsorptively separating components from a feed stream, in accordance with another aspect, is illustrated in FIG. 5. The method, in accordance with this aspect, may include a primary wash of 505, similar to that described above with respect to FIG. 4. In contrast to the primary washing of 405 described above, however, the primary washing of 505, in accordance with these aspects, is sent to a different transmission line of the cleaning zone 55, instead of being combined with the feed stream 5. More specifically, the method includes flushing the residual fluid in the intermediate transfer line 510 from the purification zone 55 between the transmission line of the feed stream 5 of the raw material and the transmission line of the extract stream 15 from the adsorption separation chambers 100 or 105 to remove at least a portion of the residual fluid media from the intermediate transmission line 510 through the primary flushing 505. The method further includes: sending the residual fluid washed from the intermediate transmission line 510 to another intermediate line 515 ne edachi purification from zone 55, for washing residual fluid in the other intermediate transmission line 515 to purification zone located near other intermediate transmission line 515 through a primary washing in 520.

In accordance with one aspect, another intermediate transmission line 515 includes residual starting material fluid remaining in the intermediate transmission line 515 from the source material line 5, which occupies the intermediate transmission line 515 during the previous step. Thus, when the flushing fluid is supplied to the intermediate transmission line 515 during the primary flushing 520, the residual fluid of the starting material is introduced into the cleaning zone 55 of the adsorption separation chambers 100 or 105. However, since the feed stream has already been shifted downstream of the primary stream in the transfer line 515, the residual fluid of the feed is introduced into the intermediate location of the treatment zone. Thus, in one approach, in order to increase the amount of separation of components contained in the residual feed in the cleaning zone 55, a primary flush in the transfer line 515 is arranged between the primary flush from the transfer line 510 and the transfer line currently occupied by the feed stream 5 , so that the residual fluid of the source material enters the area of the cleaning zone near the stream of source material. In one example, the primary flushing in the transmission line 515 is located in two transmission lines of the transmission line of the source material stream, and in another example, within the same transmission line of the transmission line of the source material stream, to increase the amount of separation of the components of the residual source material fluid that appear in zone 55 cleaning.

The above description with respect to the primary flushing of 405, with reference to FIG. 4 also relates to a primary flush 505, in accordance with the aspect of FIG. 5, except that since the residual fluid in the intermediate transmission line is supplied to the transmission line 515 for primary washing at 520, the intermediate transmission line 510 will not include the primary fluid of the starting material when the primary washing begins, as was the case with the primary washing 405 described above. In this regard, the residual fluid within the intermediate transmission line 510, instead, will include the fluid previously washed from the primary flush on the transmission line 510 during the primary flush on the transmission line 515 during the previous step, and thus will include the primary purification zone fluid sampled from purification zone 55 as described above with respect to primary flushing 405.

Returning to FIG. 6, a method for adsorptively separating components of a feed stream in accordance with another aspect is provided. In accordance with this aspect, as described above, the extract stream 15 is taken from the adsorption separation chamber 100. The extract stream 15 can be transferred to an extract separation device, for example, an extract fractionation column 175 for separating a preferably adsorbed component from the extract stream 15. The extract stream 15 may be directed into the inlet 190 of the extract fractionation column through the extract stream removal line 15 ′.

The method in accordance with this aspect includes flushing an intermediate transfer line 610 from the adsorption zone 60 between the transmission line of the extract stream 15 and the desorbent stream transmission line 10 in the direction from the adsorption separation chamber 100 through the secondary washing 605 to remove residual fluid from intermediate transmission line 610. The method further includes: sending the residual fluid washed from the intermediate transmission line 610 to a downstream separation device for separating components of the residual fluid. In accordance with one aspect, since the intermediate transmission line 610 was previously occupied by the extract stream 15, the residual fluid in the intermediate transmission line 610 includes mainly the extract fluid when the secondary flushing 605 begins. In this regard, the residual fluid of the extract may be directed to a separation device located downstream to separate the preferably adsorbed component from the fluid of the extract, to increase the yield of preferably adsorbed to mponenta.

In accordance with one aspect, the residual extract fluid washed from the intermediate transfer line 610 is guided to the inlet 175 of the extract fractionation column so that preferably the adsorbed component can be separated from the residual extract fluid by distillation to increase the yield of the extract product 195.

In one aspect, the secondary flushing 605 includes flushing the residual fluid in the intermediate fluid line 610 to wash the desorption zone taken from the desorption zone 60 of the adsorption separation chamber 100 through a corresponding port of the intermediate transmission line 610. In one example, the intermediate transmission line 610 is within two transmission lines for the transmission line currently occupied by desorbent stream 10, and, in another example, is within the same transmission line for the transmission line currently occupied by desorbent stream 10, such thus, the desorption zone flushing fluid is similar in composition to the desorbent stream 10. Thus, the fluid for flushing the desorption zone remains in the intermediate transmission line 610 after a secondary flushing 605 occurs. After the desorbent stream is shifted to the intermediate transmission line 610, in a subsequent step, the residual fluid of the desorption zone remaining in the intermediate transmission line 610 , enters the adsorption separation chamber 100 with the desorbent stream so that the fluid in the desorbent zone will be similar in composition to the desorbent stream 10.

In accordance with another aspect, a method is provided for adsorptively separating components of a feed stream, which comprises washing an intermediate transfer line located between two of: feed stream 5, extract stream 15, desorbent stream 10, and raffinate stream 20, to remove residual fluid from an intermediate transmission line. The method, in accordance with this aspect, generally includes flushing the intermediate transmission line at a dynamic or variable volumetric flow rate for at least two different parts of the time interval of the step.

As described above, in accordance with various aspects of the invention, countercurrent adsorption separation includes introducing a feed stream 5 comprising at least one preferably adsorbable component and at least one non-preferred adsorbent extract component and desorbent stream 10 to two different ports 25 through two different corresponding transmission lines along the adsorption separation chamber with a plurality of layers having a plurality of layers that are connected in series so that they communicate fluid and contain a predetermined number of ports that are interconnected with respective transmission lines communicating with each other in fluid, for introducing and removing fluid into and out of the adsorption separation chamber, and for removing the extract stream 15 and the raffinate stream 20 through two different ports adsorption separation chambers with multiple layers through two different respective transmission lines. The various streams that enter and discharge into and out of the adsorption separation chambers 100 and 105 are sequentially or stepwise shifted down to the subsequent ports. Different streams are usually stepwise shifted simultaneously to subsequent ports 25, for example, by turning the rotary valve 300 and maintained at a specific port 25 or at a specific stage for a given period of time for the stage. As described above, in one approach, there are from 4 to 100 ports 25, from 12 to 48 ports in another approach, and from 20 to 30 ports in another approach and an equal number of corresponding transmission lines. In one example, the adsorption separation camera or cameras 100 and 105 include 24 ports, and each stream is shifted to each of the 24 ports 25 during a full cycle so that each stream occupies each port 25 and its corresponding transmission line during this cycle. In this example, the cycle can last from 20 to 40 minutes in one approach and from 22 to 35 minutes in another approach. In one approach, the step time interval is from 30 seconds to two minutes. In another approach, the step time interval is from 45 seconds to one minute thirty seconds. In yet another approach, the step interval is from 50 seconds to one minute and 15 seconds.

In this regard, the method includes flushing an intermediate transmission line between two lines currently occupied by two typical streams, including a feed stream 5, a desorbent stream 10, an extract stream 15 and a raffinate stream 20, at a non-uniform or dynamic space velocity flow during the time interval of the stage. In accordance with one aspect, the method includes flushing an intermediate transmission line at a first flow rate for a first portion of a time interval of a step. The method includes flushing the intermediate transmission line at a second flow rate during the second part of the step time interval that follows the first part of the step time interval. Thus, a larger volume of fluid is flushed from the intermediate transmission line during one of the first and second parts of the step time interval than during the other part. Flushing the transmission line at a variable flow rate can provide performance benefits in terms of the composition of the fluid being flushed into and out of the intermediate transmission line, as well as with respect to the point in time of fluid injection into or from the intermediate transmission line.

In one aspect, a variable flow rate may include a gradually increasing or exponentially increasing or decreasing flow rate, which increases or decreases over at least a portion of the time interval of the step. In this regard, a gradually increasing flow rate can increase or decrease over part of the time interval of the step and can vary linearly or nonlinearly, for example, exponentially, during this time. In accordance with another aspect, the inconsistent flow rate may include the step of increasing or decreasing the flow rate so that one or both of the first flow rate and the second flow rate is constant, and one of them differs from the other for the first flow rate and second speed flow. In yet another aspect, a variable flow rate may include a combination of varying velocity portions, and an increased and decreased volumetric flow rate step. The variable flow rate may also include additional flow rates during additional parts of the time interval of the step. The flow rate may increase, decrease, or remain unchanged during any given stage. In addition, the flow rate may vary from the initial value to a higher value, lower value, or zero value at the end of the step. In FIG. 10-12 illustrate examples of variable flow rates, in accordance with various aspects of the invention. In FIG. 10 illustrates a varying flow rate 1015 that increases over time 1020 during at least a portion of the time interval of the step. In this example, the first flow rate 1005 is lower than the second flow rate 1010 such that a larger volume of fluid is flushed during the second part of the step time interval than during the first part. In another example, the changing flow rate decreases over time so that the first flow rate is greater than the second flow rate so that a larger volume of fluid is washed during the first part of the time interval of the step than during the second part. In FIG. 11, on the other hand, illustrates an example of a variable stepwise varying flow rate. In this example, the flow rate 1115 at the beginning, in general, is the first steady-state flow rate 1105 during the first part of the step time interval 1120 and increases to the second and, generally, constant higher flow rate 1110 during the second part of the step time interval 1120. In another example, the stepwise varying flow rate has a second, generally steady-state flow rate during the second part of the step time interval, which is lower than the first flow rate so that more fluid volume will be flushed during the first part of the step time interval. The volumetric flow rate during one of the first and second parts may be zero, in accordance with various aspects. In yet another example shown in FIG. 12, the flow rate 1215 in the first portion of the step time interval 1220 starts at the first flow rate 1205 and then includes a second flow rate 1210, which exponentially decreases during the second part of the step time interval 1220. Other flow rate profiles are also contemplated, in accordance with various aspects of the invention, which have different first and second flow rates during the respective first and second parts of the step time interval, and there may be additional parts of the step time interval with different flow rates.

In accordance with one aspect, one of the first and second flow rates is sufficient to flush from 50% to 400% of the volume of the flushed transmission line and associated valves so that most or all of the residual fluid in the transmission lines will be flushed during the first or second parts of the stage time interval. In accordance with another aspect, one of the first and second flow rates is sufficient to flush from 75% to 200% of the volume of the transmission line and associated valves during the first or second part of the time interval of the step. In yet another aspect, one of the first and second flow rates is sufficient to flush from 90% to 150% of the volume of the transmission line and associated valves during the first or second part of the time interval of the step. Other of the first and second flow rates, in accordance with various aspects, may be sufficient to flush from 0% to 75% of the volume of transmission lines and valves in one approach, from 0% to 50% of the volume of transmission lines and valves in another approach, and from 0% to 25% of the volume of the valve transmission lines in another approach.

In accordance with one aspect, the first flow rate is higher than the second flow rate, therefore, a larger volume of fluid will be flushed during the first part of the step time interval than during the second part of the step time interval. The method, in accordance with this aspect, may be particularly useful when the method includes flushing the residual fluid in the intermediate transmission line into the adsorption separation chamber 100 and 105 so that the residual fluid has a longer residence time in the chambers 100 and 105 before it is subsequently selected, than it could be if the flow rate were constant during the time interval of the step, or if the second flow rate was greater than the first flow rate.

In accordance with another aspect, the second flow rate is greater than the first flow rate, therefore, a larger volume of fluid is flushed during the second part of the step time interval than during the first part of the step time interval. The method, in accordance with this aspect, may be particularly useful when the residual flushing fluid is flushed away from the adsorption separation chambers 100 and 105, and the flushing fluid is withdrawn from the adsorption separation chambers 100 and 105. In this regard, the flushing fluid has a longer residence time in the adsorption separation chamber than when a constant flow rate is used or when the first flow rate is greater than the second flow rate. This preferably provides greater separation of the components in the flushing fluid so that the flushing fluid will be more similar in composition than the subsequent stream taken from or introduced into the adsorption separation chambers 100 and 105.

In more detail, the following examples, in general, include a method in which a feed stream 5 and a desorbent stream 10 are introduced into different ports 25 through different transmission lines of the adsorption separation chambers 100 and 105. The extract stream 15 and the raffinate stream 20 are sampled through two other ports 25, along two different transmission lines of the adsorption separation chambers 100 and 105. In accordance with one aspect, as shown, for example, in FIG. 7, a primary flush at 720 includes flushing the intermediate transfer line 715 between the transfer line currently occupied by the feed stream 5 during the step and the transfer line occupied by the extract stream 15 during the step. The residual fluid in the transmission line 715 may include substantially the residual fluid of the starting material. The method in accordance with this aspect includes flushing the transmission line 715 with a higher first volumetric flow rate during the first part of the step time interval than the second volumetric flow rate during the second part of the step time interval. Thus, a larger volume of the residual fluid of the starting material will be washed in the adsorption separation chambers 100 or 105 during the initial first part of the step time interval than during the subsequent second part. In this regard, the residual fluid of the starting material, washed in the adsorption separation chambers 100 or 105, has a longer residence time in the adsorption separation chambers 100 and 105 and access to the absorber in it to separate the non-preferred adsorbed component before it is taken through the extract stream 15 for subsequent stage. In accordance with another aspect, the method includes primary flushing 710, which includes flushing an intermediate transmission line 705 from an adsorption fluid separation chamber 100 or 105 taken from this chamber as described above. In one example, the method includes flushing the transmission line 705, which may include the residual extract fluid that the extract stream at the first volumetric flow rate used to occupy during the first part of the time interval of the step, which is less than the second volumetric flow rate during the second subsequent part of the time interval of the stage. Thus, the flushing fluid withdrawn from the desorption zone 60 may include a fluid similar in composition to the desorbent stream 10. The method may include washing the residual fluid of the extract from the intermediate transmission line 705 in the intermediate transmission line 715 to flush the residual fluid of the starting material in the intermediate stream 715 of the extract into the purification zone 55. In one approach, the method includes flushing the fluid with a first flow rate during the first part of the step time interval, which is greater than the second flow rate during the second part of the step time interval, so that a larger volume of the residual fluid of the starting material enters zone 55 purification during an earlier portion of the time interval of the step in such a way that a greater degree of fluid separation of the starting material in the purification zone 55 can be achieved before the extract stream 15 arrives after this and will be selected through an intermediate transmission line 715 to increase the purity of the extract stream.

Similarly, with reference to FIG. 6 described above, a method will be briefly described that may, instead, include a secondary flush 605, which includes flushing the intermediate transmission line 610 and directing the residual fluid flushed therefrom to a subsequent separation device including , in one example, an extract fractionation column 175 for separating a preferably absorbed component from the residual extract fluid into an intermediate transfer line 610. The method in accordance with this aspect may include flushing the intermediate transmission line 610 with a first volumetric flow rate during the first part of the step time interval, which is less than the second volumetric flow rate during the second subsequent part of the step time interval. Thus, the selection of the flushing fluid from the desorption zone 60 may include a fluid similar in composition to the desorbent stream 10.

In accordance with another aspect, the intermediate transmission line 725 may be flushed with a flushing fluid to introduce residual fluid in the intermediate transmission line to the cleaning zone 55. In accordance with such an aspect, this method may include flushing the intermediate transmission line 725 with a first flow rate during a first part of a step time interval that is greater than a second flow rate during a subsequent second part of a step time interval so that a larger volume the residual fluid in the transmission line 725 will be washed into the cleaning zone 55 during the first part of the step time interval than during the second part. Thus, the residual fluid will be present in the treatment zone for a longer residence time to separate the components contained therein before it is taken out by the extract stream 15, which enters the intermediate transfer line 725 in a subsequent step.

In another aspect, the intermediate transmission line 735 may be flushed with a flushing fluid from the adsorption separation chambers 100 or 105 to remove residual fluid from it. In one approach, the intermediate transmission line includes residual raffinate from the raffinate stream 20, which occupied the intermediate transmission line 735 during the previous step of the cycle. In accordance with this aspect, the method includes flushing an intermediate flushing fluid line 735 drawn from the absorption zone 50 at a first flow rate during a first part of a step time interval that is less than a second part of a step time interval. Thus, a flushing fluid will be present in the adsorption separation chamber 100 or 105 for a longer time before it is drawn through an intermediate transmission line to flush the residual fluid of the starting material therefrom. Accordingly, the flushing fluid from the absorption zone 55 will have a composition similar to the feed stream and will include a smaller amount of the non-preferred adsorbed component of the raffinate stream. After washing the intermediate transmission line, the washing fluid remains in it as the residual fluid into which the source material stream 5 will be supplied when the source material stream 5 enters through the intermediate transmission line 735 during the next step, in order to reduce the excess feed stream contamination an adsorbent component which is not preferable.

Returning to FIG. 1, 4 and 5, in accordance with various aspects as described above, the intermediate transmission lines 45, 415 or 510 may be flushed from the adsorption separation chambers 100 or 105 to remove residual fluid from them. Intermediate transmission lines 45, 415, or 510 may be flushed by withdrawing a flushing fluid from the cleaning zone 55 to an intermediate transfer line, for displacing the residual fluid from the adsorption separation chambers 100 or 105, and the residual flushing fluid from the zone will subsequently be filled 55 cleaning. In accordance with one aspect, the method includes flushing an intermediate transmission line 45, 415, or 510 with a first flow rate during a first part of a step time interval and a second flow rate that is greater than a first flow rate during a subsequent second part of a time interval stage. Thus, the flushing fluid will remain in the cleaning zone 55 for additional time, and will have access to the absorber therein to separate the component which is not preferably adsorbed, so that when the fluid in the cleaning zone is selected to flush the intermediate line 45, 415 or 510 transfer, it will be similar in composition to the stream 15 of the extract, which will be selected through it during the next stage. The method, in accordance with this aspect, preferably reduces the amount of the non-preferred adsorbed component that remains in the residual fluid within the intermediate transmission line 45, 405 or 510, which otherwise would contaminate the extract stream 15 during extraction through it, thus increasing the purity of the extract stream 15. In one approach, as described above, the intermediate transmission line 415 communicates with the feed stream so that the residual fluid leached from the intermediate transfer line is combined with the feed stream 5. In another approach, as described above, the intermediate transmission line 510 communicates with another intermediate transmission line 515 so that the residual fluid contained therein is flushed into another intermediate transmission line 515 to flush the residual fluid contained therein to the subsequent part of treatment zone 55.

In accordance with various aspects, the volumetric flow rate of a fluid through transmission lines during their dynamic flushing can be controlled using valves and a controller. Valves can be integrated into transmission lines by themselves to control or limit the volumetric flow rate of a fluid flowing through them. A controller may be provided to control the valves and the flow rate of the fluid through the transmission lines. The valves can also be integrated at other locations in the system, for example, downstream of the rotary valve 300 when the rotary valve is installed, or in lines located downstream to transfer fluid to components downstream of the system for example, in lines 15 ′ and 20 ′, for transferring fluid to an extract fractionation column 175 or a raffinate fractionation column 150, respectively.

When choosing an adsorbent for the present simulated moving bed method, the only limitation is the effectiveness of the particular adsorbent / desorbent combination for the desired separation. An important characteristic of the adsorbent is the exchange rate of the desorbent component of the extract in the feed mixture of the starting material or, in other words, the relative rate of desorption of the component. This characteristic directly relates to the amount of desorbent material that you want to use in the method to extract the extract component from the adsorbent. The high exchange rate reduces the amount of desorbent material needed to remove the extract component, and therefore, provides the opportunity to reduce operating costs in the method. At high exchange rates, less desorbent material needs to be pumped during the process and separated from the extract stream for reuse in the process.

In practice, the invention, in accordance with this subject, is therefore not related to or is not limited to the use of any particular adsorbent or adsorbent / desorbent combination, since different sieve / desorbent combinations are used for different separation. The adsorbent may or may not be a zeolite. Examples of scavengers that can be used in the process of this invention include non-zeolitic molecular sieves, including carbon, silicalite, and crystalline aluminosilicate molecular sieves, classified as zeolites X and Y. Details on composition and the synthesis of many such microporous molecular sieves are presented in US 4793984, which is presented here for this description. Information on adsorbents can also be obtained from US 4385994; US 4,605,492; US 4,310,440 and US 4,440,871.

In adsorption separation methods that generally operate continuously at substantially constant pressure and temperature to provide a liquid phase, the desorbent material must be selected so that it satisfies several criteria. Firstly, the desorbent material must displace the extract component from the adsorbent with acceptable mass flow rates so that it is not very absorbed by itself to prevent unnecessary displacement of the desorbent material by the extract component in the next adsorption cycle. When expressed in terms of selectivity, it is preferable that the adsorbent be more selective for all components of the extract with respect to the raffinate component than with respect to the desorbent material with respect to the raffinate component. Secondly, the desorbent materials must be compatible with a particular adsorbent and a specific mixture of the starting material. More specifically, they should not reduce or disrupt the adsorbent performance or adsorbent selectivity for a given extract component in relation to the raffinate component. In addition, the desorbent materials should not chemically react or cause a chemical reaction, neither with the extract component nor with the raffinate component. Both the extract stream and the raffinate stream are usually removed from the pore volume of the adsorbent mixed with the desorbent material, and any chemical reaction involving the desorbent material and the extract component or the raffinate component, or both, would make it difficult or impossible to ensure product recovery. The desorbent should also be easily separated from the components of the extract and raffinate, for example, by fractionation. Ultimately, desorbent materials should be readily available and affordable. The desorbent may include heavy or light desorbent, depending on the particular application. The terms heavy and light refer to the boiling point of the desorbent relative to C8 aromatic hydrocarbons, namely, ortho-, meta-, paraxylene and ethylbenzene. For a person skilled in the art it will be understood that the designation "C8" refers to a compound containing eight (8) carbon atoms. In some embodiments, the heavy desorbent is selected from the group consisting of para-diethylbenol, para-diisopropylbenzene, tetralin, and the like. and their combinations. In some embodiments, the implementation of toluene and the like. can be used as a light desorbent. Paradiethylbenzene (p-DEB) has a higher boiling point than the aromatic isomers of C8 and wherein p-DEB is the lower product (i.e. heavy) when separated from the C8 isomers in a fractional distillation column. Likewise, toluene has a lower boiling point than the aromatic isomers of C8, and thus, toluene is the top product (i.e., light) when it is separated from the C8 isomers in a fractional distillation column. p-DEB has become the commercial standard for use as a desorbent in the separation of paraxylene.

Adsorption conditions generally include a temperature range of 20 ° to 250 ° C, with temperatures of 60 ° to 200 ° C being preferred for the separation of paraxylene. Adsorption conditions also include a pressure sufficient to maintain the liquid phase, which can be from atmospheric to 2 MPa. Desorption conditions generally include the same temperature and pressure ranges that are used for adsorption conditions. Different conditions may be preferred for other compounds of the extract.

The above description and examples are intended to be used as illustrations of the invention, without limiting its scope. Although specific embodiments of the present invention have been presented and described, it should be understood that various changes and modifications will be apparent to those skilled in the art, and it is intended that the appended claims cover all such changes and modifications that fall within the true spirit. and scope of the present invention.

Claims (11)

1. A method for separating components in a feed stream by simulated adsorption countercurrent separation, including:
introducing a feed stream comprising at least one preferably adsorbent component and at least one non-preferred adsorbent component and a desorbent stream into two different ports through two different respective transmission lines along the adsorption separation chamber with a plurality of layers having multiple layers that are arranged in series so that they communicate in fluid and containing a predetermined number of spaced apart ports with corresponding transmission lines, reporting Misia in fluid communication with each other for supplying and removing fluid to and from adsorptive separation chamber, and selection of an extract stream and a raffinate stream via two different adsorptive separation chamber port with a plurality of layers of two different respective transmission lines;
washing the residual fluid in an intermediate transmission line of the cleaning zone between the transmission line of the feed stream of the material and the transmission line of the extract stream in the direction from the adsorption separation chamber to remove at least a portion of the residual fluid from the intermediate transmission line; and
the direction of the residual fluid washed from the intermediate transmission line to another transmission line. 2. The method of claim 1, wherein the residual fluid leached from the intermediate transmission line is directed to another transmission line, which is not a transmission line of the cleaning zone, to limit the residual fluid supplied to the cleaning zone. 3. The method of claim 2, wherein the residual fluid is combined with the feed stream and fed to the adsorption separation chamber through a feed line of the feed material so that the residual fluid can be separated in the adsorption separation chamber. 4. The method according to any one of paragraphs. 2 and 3, in which the intermediate transfer line was previously occupied by the feed stream, so that the residual fluid contains mainly feed which is removed from the transfer line to limit the selection of the source material with the extract stream when the extract stream is subsequently shifted to the intermediate line transmission. 5. The method according to any one of paragraphs. 2 and 3, in which the residual fluid is pumped into the feed stream to overcome the pressure difference between the intermediate transfer line and the transfer line of the feed stream. 6. The method of claim 1, wherein the residual fluid leached from the intermediate transmission line is sent to another intermediate transmission line of the cleaning zone to flush the residual fluid of the other transmission line to the cleaning zone to separate the preferably adsorbed component from the non-preferably adsorbed component present in residual fluid in another transmission line. 7. The method according to claim 6, in which another intermediate transmission line is located between the intermediate transmission line and the feed stream so that the residual fluid enters a part of the cleaning zone, next to the feed stream. 8. The method according to claim 6, in which the other intermediate transmission line was previously occupied by the flow of the source material so that the residual fluid of the other intermediate transmission line contains mainly the fluid of the starting material, which is washed in the cleaning zone to separate its components. 9. The method according to claim 7, in which the other intermediate transmission line was previously occupied by the flow of the source material so that the residual fluid of the other intermediate transmission line contains mainly the fluid of the starting material, which is washed in the cleaning zone to separate its components. 10. The method according to any one of paragraphs. 6-9, in which the other intermediate transmission line is within two transmission lines from the transmission line currently occupied by the feed stream to allow separation of the residual fluid. 11. The method according to any one of paragraphs. 2 and 6, wherein flushing the intermediate transmission line involves taking a fluid from a cleaning zone of the adsorption separation chamber, defined as the region of the adsorption separation chamber between the port to which the feed material is supplied and the port from which the extract is taken, next to the transmission line, and displacing residual fluid into the fluid line of the cleaning zone.

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