Simulated moving bed adsorption separation system, flushing device and method

Abstract

The present application relates to a simulated moving bed adsorption separation system, a flushing device and a method. The flushing device includes a fluid distributor and a circulation pipeline. In the application of the simulated moving bed adsorption separation process, the adsorption separation system of the present application can reduce the material disturbance in the adsorption tower, does not affect the regional flow rate in the adsorption tower, improves the adsorption separation performance, and can flexibly adjust the proportion of the flushing flow rate; and can improve the purity and yield of the target product and reduce the desorbent / raw material ratio.

Description

Technical Field

[0001] The present invention relates to the field of simulated moving beds, and more specifically, to a simulated moving bed adsorption separation system, a feed flushing device for the simulated moving bed adsorption separation system, and an adsorption separation method. Background Art

[0002] Simulated moving beds are usually used to separate components with relatively close relative volatilities but different structural characteristics. Common separated components include p-xylene and other mixed xylenes, normal and isoparaffins with similar carbon atom numbers, etc. In a simulated moving bed, the material flows countercurrently to the adsorbent, and the positions of the inlet and outlet materials are periodically changed. The simulated moving bed process is introduced in detail in patents such as WO2013013493A1 and CN102895800A.

[0003] In a typical simulated moving bed process, there are usually two feeds (raw material F and desorbent D) and two products (extract E and raffinate R). The extract is the material enriched with the target product, and the raffinate is the remaining material after separating the target product. Each stream of material periodically changes its position of entering and leaving the adsorption tower to achieve the simulated movement of the adsorbent relative to the material bed. In a complete simulated moving bed process, the number of adsorption towers can be 1 - 2. The materials in the adsorption tower are connected end to end and flow in a self - circulating manner. The flow of materials into and out of the adsorption tower can be controlled by a rotary valve or a programmable control valve.

[0004] During the operation of the simulated moving bed, in different step cycles, the raffinate R, raw material F, extract E, and desorbent D will respectively pass through the same bed layer pipeline. To avoid the residual material in the pipeline from contaminating the material passing through this pipeline later, changing the concentration of the feed components, disturbing the concentration distribution of components in the bed layer, and resulting in a decrease in the purity and yield of the target product, after the material flows through the bed layer pipeline, the bed layer pipeline needs to be flushed.

[0005] CN1174750A discloses a flushing device in a simulated moving bed adsorption device. The device is characterized in that there is a flushing valve on the distribution pipeline of each bed layer. The flushing valve is connected to a circulation pipeline, and the internal reflux liquid is used to flow through the built - in flushing pipeline to flush the material pipeline. In a part of the operation cycle, the fluid in a specific common section is extracted and discharged into an external collector. In another part of the operation cycle, the fluid in the external collector is extracted for pipeline flushing and then discharged into another common section of the adsorption tower. The entire flushing process requires the volume of the flushing material to be greater than the sum of the volume of the pipeline in this bed layer and the volume in the fluid distributor.

[0006] However, the current pipeline flushing method used in the simulated moving bed adsorption separation system still has the following problems that need to be improved:

[0007] (1) Using the materials outside the tower for pipeline flushing, after the materials enter the adsorption tower, it will affect the regional flow rate inside the adsorption tower;

[0008] (2) The flushing materials used are inconsistent with the materials inside the corresponding bed layer of the adsorption tower, increasing the component concentration disturbance inside the adsorption tower;

[0009] (3) Using materials such as the extract and desorbent for pipeline flushing reduces the output of the extract and increases the circulation volume of the materials and desorbent. SUMMARY OF THE INVENTION

[0010] The object of the present invention is to provide a simulated moving bed adsorption separation system, as well as a flushing method and a separation method. The system and method can use materials consistent with the fluid components inside the tower to flush the inlet and outlet material pipelines without affecting the regional flow rate of the simulated moving bed adsorption tower, and the flushing flow ratio can be flexibly adjusted, reducing the number of control valves, simplifying the inlet and outlet material pipelines and their flushing processes.

[0011] On the one hand, the present application provides a feed flushing device for a simulated moving bed, which includes:

[0012] A fluid distributor, wherein the fluid distributor is arranged inside the simulated moving bed, and the fluid distributor includes:

[0013] An upper surface support member having a channel for fluid to pass through,

[0014] A lower surface fluid distribution member having a channel for fluid to pass through,

[0015] A partition plate horizontally extending through the cross-sectional area of the fluid distributor, which divides the inner chamber of the fluid distributor formed by the upper surface support member and the lower surface fluid distribution member into an upper compartment and a lower compartment. The upper compartment is a fluid collection chamber, and the lower compartment is a fluid distribution chamber;

[0016] A mixing chamber arranged inside the fluid distributor, the upper layer of the mixing chamber is in fluid communication with the fluid collection chamber, and the lower layer of the mixing chamber is in fluid communication with the fluid distribution chamber, so that the external fluid entering the fluid collection chamber enters the fluid distribution chamber after passing through the mixing chamber and is discharged from the fluid distributor through the lower surface fluid distribution member;

[0017] A circulation pipeline, the circulation pipeline includes:

[0018] An inlet and outlet material pipeline, which is connected to the upper layer of the mixing chamber;

[0019] A flushing pipeline, which is connected to the lower layer of the mixing chamber;

[0020] A flushing pump, which is connected to the incoming and outgoing material pipeline and the flushing pipeline.

[0021] In one embodiment, a first control valve is provided between the connection port of the incoming and outgoing material pipeline and the upper layer of the mixing chamber and the flushing pump; a second control valve is provided between the connection port of the flushing pipeline and the lower layer of the mixing chamber and the flushing pump.

[0022] In one embodiment, a flow controller is further provided in the circulation pipeline.

[0023] In one embodiment, a part of the flushing pipeline is sleeved inside the incoming and outgoing material pipeline.

[0024] In one embodiment, the flushing pipeline and the incoming and outgoing material pipeline are arranged side by side.

[0025] In one embodiment, the size of the flushing pipeline is not larger than the size of the incoming and outgoing material pipeline.

[0026] In one embodiment, the following are further provided on the incoming and outgoing material pipeline:

[0027] A raw material inlet communicating with the raw material feed pipeline,

[0028] A desorbent inlet communicating with the desorbent feed pipeline,

[0029] An extract outlet communicating with the extract discharge pipeline, and

[0030] A raffinate outlet communicating with the raffinate discharge pipeline.

[0031] In a second aspect, the present application provides a simulated moving bed adsorption separation system, including an adsorption tower, the adsorption tower includes a plurality of tower sections, and each tower section includes a fluid distributor and an adsorbent bed layer;

[0032] Wherein, inside the adsorption tower, the fluid distributors and the adsorbent bed layers of each tower section are arranged alternately;

[0033] Wherein, the fluid distributor of each tower section includes:

[0034] An upper surface support member having a channel for fluid to pass through,

[0035] A lower surface fluid distribution member having a channel for fluid to pass through,

[0036] A partition plate horizontally extending through the cross-sectional area of the fluid distributor, the partition plate divides the internal chamber of the fluid distributor formed by the upper surface support member and the lower surface fluid distribution member into an upper compartment and a lower compartment, the upper compartment is a fluid collection chamber, and the lower compartment is a fluid distribution chamber;

[0037] A mixing chamber disposed inside the fluid dispenser, the upper layer of the mixing chamber being in fluid communication with the fluid collection chamber, and the lower layer of the mixing chamber being in fluid communication with the fluid distribution chamber, such that the external fluid entering the fluid collection chamber enters the fluid distribution chamber after passing through the mixing chamber and is discharged from the fluid dispenser through the lower surface fluid distribution member;

[0038] Wherein, a circulation pipeline is further connected to the fluid dispenser of each tower section, and the circulation pipeline includes:

[0039] An inlet and outlet material pipeline, which is connected to the upper layer of the mixing chamber;

[0040] A flushing pipeline, which is connected to the lower layer of the mixing chamber;

[0041] A flushing pump, which is in communication with the inlet and outlet material pipeline and the flushing pipeline;

[0042] Wherein, the following are further provided on the inlet and outlet material pipeline:

[0043] A raw material inlet connected to the raw material feed pipeline,

[0044] A desorbent inlet connected to the desorbent feed pipeline,

[0045] An extract outlet connected to the extract discharge pipeline, and

[0046] A raffinate outlet connected to the raffinate discharge pipeline.

[0047] In one embodiment, a first control valve is provided between the connection port of the inlet and outlet material pipeline and the upper layer of the mixing chamber and the flushing pump; a second control valve is provided between the connection port of the flushing pipeline and the lower layer of the mixing chamber and the flushing pump;

[0048] A flow controller is further provided in the circulation pipeline.

[0049] In one embodiment, a part of the flushing pipeline is sleeved inside the inlet and outlet material pipeline.

[0050] In one embodiment, the flushing pipeline and the inlet and outlet material pipeline are arranged side by side.

[0051] In one embodiment, the size of the flushing pipeline is not greater than the size of the inlet and outlet material pipeline.

[0052] In a third aspect, the present application provides a pipeline flushing method for a simulated moving bed adsorption separation system, and the pipeline flushing method is carried out in the simulated moving bed adsorption separation system of the present application,

[0053] The method includes:

[0054] In the flushing step, the first control valve, the second control valve, and the flushing pump are opened. The material is led out from the upper layer of the mixing chamber of the fluid distributor through the port of the inlet and outlet material pipeline to flush the inlet and outlet material pipeline, and the flushed material is introduced into the lower layer of the mixing chamber of the fluid distributor through the flushing pipeline; or,

[0055] In the flushing step, the first control valve, the second control valve, and the flushing pump are opened. The material is led out from the lower layer of the mixing chamber of the fluid distributor through the port of the flushing pipeline to flush the inlet and outlet material pipeline, and the flushed material is introduced into the upper layer of the mixing chamber of the fluid distributor.

[0056] In one embodiment, the total volume of the material flowing through the flushing pipeline within the flushing step is greater than the sum of the volumes of the inlet and outlet material pipeline, the flushing pipeline, and the fluid distributor.

[0057] In one embodiment, the time when the first control valve is in the open state is n times the flushing step time, where 0.2 ≤ n ≤ 1.0.

[0058] In one embodiment, the flow rate of the material in the flushing pipeline is 1 - 3 m / s.

[0059] In a fourth aspect, a method for adsorption separation using a simulated moving bed adsorption separation system according to the present application, the method is carried out in the above-mentioned simulated moving bed adsorption separation system,

[0060] The method includes:

[0061] 1) In the first step, feed the raw material into the fluid distributors of several first tower sections, feed the desorbent into the fluid distributors of several second tower sections, discharge the extract in the fluid distributors of several third tower sections, and discharge the raffinate in the fluid distributors of several fourth tower sections, and perform a flushing process in the fluid distributors of several fifth tower sections,

[0062] The flushing process includes:

[0063] Open the first control valve, the second control valve, and the flushing pump. Lead the material out from the upper layer of the mixing chamber of the fluid distributor through the port of the inlet and outlet material pipeline to flush the inlet and outlet material pipeline, and introduce the flushed material into the lower layer of the mixing chamber of the fluid distributor through the flushing pipeline; or,

[0064] Open the first control valve, the second control valve, and the flushing pump. Lead the material out from the lower layer of the mixing chamber of the fluid distributor through the port of the flushing pipeline to flush the inlet and outlet material pipeline, and introduce the flushed material into the upper layer of the mixing chamber of the fluid distributor;

[0065] 2) In the next step, change the positions of the tower sections for feeding the raw material and the desorbent, the positions of the tower sections for discharging the extract and the raffinate, and change the position of the tower section for performing the flushing process;

[0066] 3) Repeat step 2) until all steps are completed.

[0067] In the application of the simulated moving bed adsorption separation process, using the adsorption separation system of the present application can reduce the material disturbance in the adsorption tower, does not affect the regional flow rate in the adsorption tower, improve the adsorption separation performance, and can flexibly adjust the ratio of the flushing flow rate; and can improve the purity and yield of the target product, and reduce the desorbent / raw material ratio. Description of the Drawings

[0068] Figure 1 A schematic diagram showing a simulated moving bed adsorption tower;

[0069] Figure 2 A schematic diagram showing a flushing device and a flushing method;

[0070] Figure 3 A schematic diagram showing a flushing device and another flushing method;

[0071] Figure 4A and 4B A schematic diagram showing the positional relationship between the flushing pipeline and the incoming and outgoing material pipelines in the mixing chamber of the fluid distributor;

[0072] Figure 5 A schematic diagram showing two simulated moving bed adsorption towers connected in series. Detailed Embodiments

[0073] The present application will be further described in detail below with reference to the drawings and embodiments. Through these descriptions, the features and advantages of the present application will become more clearly defined.

[0074] The special term "exemplary" here means "serving as an example, embodiment or illustration". Any embodiment described here as "exemplary" does not have to be construed as superior or better than other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0075] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0076] Figure 1There is shown a simulated moving bed adsorption separation system, including an adsorption tower 1, within which there are multiple tower sections 200, and each tower section 200 includes a fluid distributor 2 and an adsorbent bed 3. During different stepping periods, various materials such as feedstock F, desorbent D, extract E, and raffinate R can be fed and discharged in the fluid distributors 2 of different tower sections 200, and the various materials perform adsorption-desorption distribution within the adsorbent bed 3.

[0077] In the simulated moving bed adsorption separation system of the present application, multiple adsorption towers 1 can be included, and these adsorption towers 1 can be arranged in series or in parallel. For example, 1 - 2 adsorption towers 1 arranged in series can be included.

[0078] The fluid distributor 2 of each tower section 200 is connected to a material inlet and outlet pipeline 4 and extends outside the adsorption tower. On the material inlet and outlet pipeline 4 outside the adsorption tower, there are successively arranged a raffinate R discharge pipeline 5 for discharging raffinate R, a feedstock F inlet pipeline 6 for introducing feedstock F, a desorbent D inlet pipeline 7 for introducing desorbent D, and an extract E discharge pipeline 8 for discharging extract E. Generally speaking, within the adsorption tower, the area between the injection of raffinate and the extraction of extract is called the desorption zone, the area between the extraction of extract and the injection of feedstock is called the purification zone, the area between the injection of feedstock and the extraction of raffinate is called the adsorption zone, and the area between the extraction of raffinate and the injection of desorbent is called the buffer zone. In one embodiment, the simulated moving bed system can have two adsorption towers and 24 beds, where the desorption zone has 4 - 7 beds, the purification zone has 7 - 10 beds, the adsorption zone has 4 - 7 beds, and the buffer zone has 2 - 4 beds.

[0079] In the simulated moving bed process, the four streams of inlet and outlet materials will periodically change their positions of entering and leaving the adsorption tower. Therefore, before changing the inlet and outlet materials in the bed pipelines, the original material pipelines need to be flushed. In order to flush the pipelines clean enough, the on-off valves on the four inlet and outlet material pipelines of raffinate R, feedstock F, desorbent D, and extract E need to be as close as possible to the main inlet and outlet material pipeline to minimize the volume of residual materials.

[0080] As Figure 1 shown, in the above - mentioned simulated moving bed adsorption separation system, within each tower section, the fluid distributor 2 is arranged above the adsorbent bed 3. The various tower sections are arranged in sequence such that the fluid distributors 2 and the adsorbent beds 3 are arranged in an alternating manner. A bottom collector 210 is further arranged at the bottom of the adsorption tower for collecting and aggregating the logistics from the upper beds, and can also support the adsorbent bed above it. The logistics collected by the bottom collector 210 can also be transported to the top of the adsorption tower through a pump (not shown). The bottom collector is not connected to a circulation pipeline.

[0081] The following Figure 2 -4 specifically describes the fluid distributor 2.

[0082] The fluid distributor 2 comprises:

[0083] A support 101 having an upper surface with channels for fluid to pass through,

[0084] A lower surface fluid distribution member 102 having channels for fluid to pass through,

[0085] A partition 110 extending horizontally through the cross-sectional area of ​​the fluid distributor, the partition dividing the internal chamber of the fluid distributor formed by the upper surface support member and the lower surface fluid distribution member into an upper compartment and a lower compartment, the upper compartment being a fluid collection chamber 16 and the lower compartment being a fluid distribution chamber 17;

[0086] A mixing chamber 120 is arranged inside the fluid distributor, and the upper layer 14 of the mixing chamber is connected with the fluid 16 of the fluid collecting chamber, and the lower layer 15 of the mixing chamber is connected with the fluid of the fluid distribution chamber 17, so that the external fluid entering the fluid collecting chamber enters the fluid distribution chamber 17 after passing through the mixing chamber, and is discharged from the fluid distributor through the lower surface fluid distribution part 102.

[0087] The upper surface support member 101 and the lower surface fluid distribution member 102 of the fluid distributor 2 have channels for fluid to pass through.

[0088] The function of the upper surface support 101 is to support the adsorbent bed 3 above the fluid distributor, to block the solid adsorbent particles in the adsorbent bed 3 above the fluid distributor from entering the fluid distributor 2, while allowing the fluid to flow into the fluid distributor 2. The component can usually be composed of two parts, upper and lower, or a combination of multiple parts. The upper part of the component adopts a special type of grid called "shaped metal wire screen", but is not limited to this structure, and can be composed of various wire meshes, grids, porous sieve plates, honeycomb materials, etc., alone or in combination. The lower part of the component can be provided with a support structure composed of a series of horizontal and vertical staggered support bars, and the support structure can also be composed of an open-pored shaped support plate, or a combination of multiple support components.

[0089] The lower surface distribution member 102 may be similar in structure to the upper portion of the upper surface support member 101, and is a device for improving and / or maintaining uniform distribution of fluid velocity, and may be composed of, for example, a porous screen plate, a formed wire mesh, a grid, a honeycomb material, a corrugated plate, and a combination thereof. The upper portion of the upper surface support member 101 and the lower surface distribution member 102 of the fluid distributor may generally be a Johnson mesh.

[0090] The upper surface support member 101 and the lower surface fluid distribution member 102 together define the internal chamber of the fluid distributor 2 of the present application. A partition 110 is provided inside the fluid distributor 2, and the partition divides the internal chamber of the fluid distributor into an upper compartment and a lower compartment. The upper compartment is the fluid collection chamber 16, and the lower compartment is the fluid distribution chamber 17. The upper surface support member 101, the lower surface fluid distribution member 102, and the partition 110 are substantially parallel to each other at reasonable intervals and are substantially perpendicular to the vertical main axis dotted line of the container. The partition 110 is usually made of a non-porous flat plate.

[0091] An internal mixing chamber 120 is also provided inside the fluid distributor 2. The outer peripheral wall of the mixing chamber 120 is provided with through holes, so that the upper layer 14 of the mixing chamber 120 is in fluid communication with the fluid collection chamber 16, and the lower layer 15 of the mixing chamber is in fluid communication with the fluid distribution chamber 17. Thus, the external fluid entering the fluid collection chamber 16 enters the fluid distribution chamber 17 after passing through the mixing chamber 120 and is discharged from the fluid distributor 2 through the lower surface fluid distribution member 102. The mixing chamber 120 is located inside the internal chamber of the fluid distributor 2 defined by the upper surface support member 101 and the lower surface fluid distribution member 102 together. The upper end of the mixing chamber 120 is flush with the upper surface support member 101, and the lower end is flush with the lower surface fluid distribution member 102. A through hole is provided on the partition 110 for sleeving the mixing chamber 120 therein, so that the partition 110 surrounds the outer periphery of the mixing chamber 120 at the through hole. The space above the partition 110 in the mixing chamber 120 is called the upper layer 14 of the mixing chamber 120, and the space below the partition 110 in the mixing chamber 120 is called the lower layer 15 of the mixing chamber 120.

[0092] The material coming from the upper adsorbent bed layer enters the fluid collection chamber 16 through the upper surface support member 101, then enters the fluid mixing chamber 120, is fully mixed with the material therein, flows to the fluid distribution chamber 17, and is discharged from the fluid distributor 2 through the lower surface fluid distribution member 102.

[0093] The fluid distributor 2 is also externally connected with a circulation pipeline, and the circulation pipeline includes:

[0094] An inlet and outlet material pipeline 4, and the inlet and outlet material pipeline 4 is connected to the upper layer 14 of the mixing chamber 120;

[0095] A flushing pipeline 9, and the flushing pipeline 9 is connected to the lower layer 15 of the mixing chamber 120;

[0096] A flushing pump 12, and the flushing pump 12 is communicated with the inlet and outlet material pipeline 4 and the flushing pipeline 9.

[0097] The raffinate R export pipeline 5, the raw material F import pipeline 6, the desorbent D import pipeline 7, and the extract E export pipeline 8 introduce or export each material through the inlet and outlet material pipeline 4 during different stepping periods. Thus, an external material circulation flushing path can be formed through the inlet and outlet material pipeline 4, the flushing pump 12, and the flushing pipeline 9, which can be used to flush the inlet and outlet material pipeline 4 during the flushing process.

[0098] In one embodiment, a first control valve 10 is provided between the connection port of the inlet and outlet material pipeline 4 with the upper layer of the mixing chamber 120 and the flushing pump 12. The valve 10 serves as a buffering function to prevent the high-pressure material flow in the adsorption tower from damaging the flushing pump when the flushing pump is started. In one embodiment, a second control valve 11 is provided between the connection port of the flushing pipeline 9 with the lower layer of the mixing chamber 120 and the flushing pump 12. When flushing is required, the flushing pump 12, the first control valve 10, and the second control valve 11 are opened. Generally speaking, it is required that the two components of the flushing inlet material flow and the flushing outlet material flow are as different as possible, and the distance between the connection port of the flushing pipeline 9 with the lower layer of the mixing chamber 120 and the connection port of the inlet and outlet material pipeline with the upper layer of the mixing chamber 120 should be as far as possible. A flow controller 13 is also provided in the circulation pipeline for flow control. The position of the flow controller 13 in the circulation pipeline can be changed as needed, and it is usually set downstream of the flushing pump.

[0099] As described above, in the simulated moving bed process, the four streams of inlet and outlet materials will periodically change their positions of entering and leaving the adsorption tower. Therefore, before changing the inlet and outlet materials in the bed layer pipeline, it is necessary to flush the original material pipeline.

[0100] The present application relates to a pipeline flushing method for a simulated moving bed adsorption separation system, which is carried out in the simulated moving bed adsorption separation system of the present application. There are two ways to carry out flushing:

[0101] The first way is to open the first control valve 10, the second control valve 11, and the flushing pump 12, draw materials from the upper layer of the mixing chamber 120 of the fluid distributor through the port of the inlet and outlet material pipeline 4, flush the inlet and outlet material pipeline 4, and introduce the flushed materials into the lower layer of the mixing chamber 120 of the fluid distributor through the flushing pipeline 9.

[0102] The second way is to open the first control valve 10, the second control valve 11, and the flushing pump 12, draw materials from the lower layer of the mixing chamber 120 of the fluid distributor through the port of the flushing pipeline 9, flush the inlet and outlet material pipeline 4, and introduce the flushed materials into the upper layer of the mixing chamber 120 of the fluid distributor.

[0103] In one embodiment, the flushing flow rate and the duration of the flushing step are controlled such that the total volume of the material flowing through the flushing pipeline 9 within the flushing step is greater than the sum of the volumes of the inlet / outlet material pipeline, the flushing pipeline, and the fluid distributor.

[0104] In one embodiment, the time during which the first control valve is in the open state is n times the flushing step time, where 0.2 ≤ n ≤ 1.0.

[0105] In one embodiment, the flow rate of the material in the flushing pipeline is 1 - 3 m / s.

[0106] The present invention simplifies the flushing process. A stream of material is directly led out from the fluid distributor, passes through the flushing pipeline and the flushing pump, and after flushing the inlet / outlet material pipeline, the stream of material is then led back to the fluid distributor. This method can use the material consistent with the fluid components in the tower to flush the inlet / outlet material pipeline without affecting the flow rate in the simulated moving bed adsorption tower area, and the flushing flow rate ratio can be flexibly adjusted, reducing the number of control valves and simplifying the inlet / outlet material pipeline and its flushing process.

[0107] Figure 4A and 4B shows the positional relationship between the flushing pipeline and the inlet / outlet material pipeline in the mixing chamber of the fluid distributor. As Figure 4A shown, a part of the flushing pipeline 9 is sleeved inside the inlet / outlet material pipeline 4. As Figure 4B shown, the flushing pipeline 9 and the inlet / outlet material pipeline 4 are arranged side by side. Generally speaking, it is required that the two components of the flushing inlet stream and the flushing outlet stream differ as much as possible, and the distance between the connection port of the flushing pipeline 9 and the lower layer of the mixing chamber 120 and the connection port of the inlet / outlet material pipeline and the upper layer of the mixing chamber 120 should be as far as possible. Therefore, in one embodiment, the outlet end of the flushing pipeline 9 in the lower layer 15 of the mixing chamber 120 is located at the lower part of the lower layer 15 of the mixing chamber 120. In one embodiment, the outlet end of the inlet / outlet material pipeline 4 in the upper layer 14 of the mixing chamber 120 is located at the upper part of the upper layer 14 of the mixing chamber 120.

[0108] In one embodiment, the size of the flushing pipeline 9 is not greater than the size of the inlet / outlet material pipeline 4.

[0109] Thus, the present application relates to a feed flushing device for a simulated moving bed, which includes:

[0110] Fluid distributor 2, wherein the fluid distributor is disposed inside a simulated moving bed, and the upper surface support member 101 and the lower surface fluid distribution member 102 of the fluid distributor 2 have channels for fluid to pass through; wherein a partition 110 is disposed inside the fluid distributor 2, and the partition divides the fluid distributor into an upper compartment and a lower compartment. The upper compartment is a fluid collection chamber 16, and the lower compartment is a fluid distribution chamber 17; a mixing chamber 120 is further disposed inside the fluid distributor. The upper layer 14 of the mixing chamber is in fluid communication with the fluid collection chamber 16, and the lower layer 15 of the mixing chamber is in fluid communication with the fluid distribution chamber 17, such that the external fluid entering the fluid collection chamber enters the fluid distribution chamber after passing through the mixing chamber and is discharged from the fluid distributor 2 through the lower surface fluid distribution member 102;

[0111] Inlet and outlet material pipeline 4, the inlet and outlet material pipeline 4 is connected to the upper layer 14 of the mixing chamber; the inlet and outlet material pipeline is in communication with a flushing pump 12;

[0112] Flushing pipeline 9, the flushing pipeline 9 is connected to the lower layer 15 of the mixing chamber; the flushing pipeline 9 is in communication with the flushing pump 12.

[0113] The above pipeline flushing method can be achieved by this feed flushing device.

[0114] This application also relates to a method for adsorption separation using a simulated moving bed adsorption separation system, and the method is carried out in the simulated moving bed adsorption separation system of this application,

[0115] The method includes:

[0116] 1) In the first step, feed raw materials into the fluid distributors of several first tower sections, feed desorbent into the fluid distributors of several second tower sections, discharge extract in the fluid distributors of several third tower sections, and discharge raffinate in the fluid distributors of several fourth tower sections, and perform a flushing process in the fluid distributors of several fifth tower sections,

[0117] The flushing process includes:

[0118] Open the first control valve, the second control valve, and the flushing pump, draw materials from the upper layer of the mixing chamber of the fluid distributor through the port of the inlet and outlet material pipeline, flush the inlet and outlet material pipeline, and introduce the flushed materials into the lower layer of the mixing chamber of the fluid distributor through the flushing pipeline; or,

[0119] Open the first control valve, the second control valve, and the flushing pump, draw materials from the lower layer of the mixing chamber of the fluid distributor through the port of the flushing pipeline, flush the inlet and outlet material pipeline, and introduce the flushed materials into the upper layer of the mixing chamber of the fluid distributor.

[0120] 2) In the next step, change the column section positions for feeding the raw material and the desorbent, the column section positions for discharging the extract and the raffinate, and change the column section position for performing the flushing process;

[0121] 3) Repeat step 2) until all steps are completed.

[0122] In this application, the column section for feeding the raw material is referred to as the first column section, the column section for feeding the desorbent is referred to as the second column section, the column section for discharging the extract is referred to as the third column section, the column section for discharging the raffinate is referred to as the fourth column section, and the column section for performing the flushing process is referred to as the fifth column section. It should be noted that the positions of these column sections in the adsorption column are not fixed and will change with the progress of adsorption.

[0123] For example, in Figure 1 the system with only one adsorption column as shown, this adsorption column has 12 column sections, and each column section includes an adsorbent bed and a fluid distributor. Thus, this adsorption column has 12 bed adsorbents and 12 fluid distributors. According to the experience of the regional division of the entire adsorption column, a possible way of dividing the adsorption separation column region is that there are 3 bed layers in the adsorption zone, 4 bed layers in the purification zone, 3 bed layers in the desorption zone, and 2 bed layers in the buffer zone, but it is not limited to this division method. A bottom collector is provided at the bottom of the adsorption column, and it has no external circulation pipeline.

[0124] An example of the operation process is as follows: In step 1, only open the desorbent D feed pipeline at the 1st column section, only open the extract E discharge pipeline at the 4th column section, only open the raw material F feed pipeline at the 8th column section, only open the raffinate R discharge pipeline at the 11th column section, and open the flushing pipeline valve and the flushing pump at the remaining column sections to make the material flow composition in the inlet and outlet material pipelines consistent with the material flow composition inside the column section.

[0125] In step 2, close the desorbent D feed pipeline at the 1st column section, open the desorbent D feed pipeline at the 2nd column section, close the extract E discharge pipeline at the 4th column section, open the extract E discharge pipeline at the 5th column section, close the raw material F feed pipeline at the 8th column section, open the raw material F feed pipeline at the 9th column section, close the raffinate R discharge pipeline at the 11th column section, open the raffinate R discharge pipeline at the 12th column section, and open the flushing pipeline valve and the flushing pump at the remaining column sections to make the total material flow composition in the inlet and outlet material pipelines consistent with the material flow composition inside the column section.

[0126] At step 3, the desorbent D feed pipeline of the second column section is closed, the desorbent D feed pipeline of the third column section is opened, the extract E discharge pipeline of the fifth column section is closed, the extract E discharge pipeline of the sixth column section is opened, the feedstock F feed pipeline of the ninth column section is closed, the feedstock F feed pipeline of the tenth column section is opened, the raffinate R discharge pipeline of the twelfth column section is closed, the raffinate R discharge pipeline of the first column section is opened, and the flushing pipeline valves and flushing pumps of the remaining column sections are opened to make the material composition in the inlet and outlet material pipelines consistent with the material composition in the column section.

[0127] According to this rule, at each step, the inlet and outlet material positions are sequentially changed to the next column section, as shown in Table 1. Table 1 is only exemplary, and those skilled in the art can change the positions, quantities, and sequences of the four inlet and outlet materials, namely desorbent D, extract E, feedstock F, and raffinate R, and the column sections for the flushing process as needed.

[0128] After 1 cycle, after 12 steps, the next cycle begins.

[0129] According to the requirements of the simulated moving bed process, the inlet and outlet material positions of the four materials, namely desorbent D, extract E, feedstock F, and raffinate R, are changed to the next column section at each step. Table 1 shows that in one implementation, within 12 steps, for each column section with inlet and outlet materials in each step cycle, for the 8 column sections that do not require inlet and outlet materials, the flushing pipeline valves and flushing pumps are opened for pipeline flushing. Except for the pipelines of the four inlet and outlet materials, the material composition in the remaining flushing pipelines is the same as the material composition in the column section of the adsorption tower. Different inlet and outlet material methods can be selected according to needs.

[0130] According to different operating conditions, Figure 2 and Figure 3 two flushing methods can be selected. Figure 2 For the material drawn from the upper layer of the fluid mixing chamber, after flushing the inlet and outlet pipelines, it enters the lower layer of the fluid mixing chamber. Figure 3 For the material drawn from the lower layer of the fluid mixing chamber, after flushing the inlet and outlet pipelines, it enters the upper layer of the fluid mixing chamber. Figure 2 and Figure 3 In, the arrows indicate the flow direction of the material, and the double-headed arrows indicate that the material can flow bidirectionally between the upper and lower layers of the mixing chamber of the fluid distributor, the fluid collection chamber, and the fluid distribution chamber.

[0131] If one step time is 80 s, the pipeline flushing time of the next column section where the desorbent D is located is set to 80 s, the pipeline flushing time of the next column section where the extract E is located is set to 80 s, and for other column sections, the flushing pump can be not turned on for 0 - 40 s and turned on for 40 - 80 s.

[0132] The volume of the pipeline to be flushed is calculated based on 0.04 m 3Calculation: The flow rate of the flushing pump is calculated at 20 m 3 / h. Then, within one step time, if the flushing time is 80 s, the flushing volume reaches 0.44 m 3 , and the flushing linear velocity is 1.1 m / s. If the flushing time is 40 s, the flushing volume is 0.22 m 3 , and the flushing volume is much larger than the pipeline volume. Therefore, the flushing pump can complete the flushing and replacement of the materials in the inlet and outlet material pipelines at a small flow rate. At the same time, in order to ensure that the flow mode of the fluid in the pipeline is close to plug flow, the flow rate of the flushing pump can be further increased, which is beneficial to improving the flushing efficiency.

[0133] The specific operations of the valves are as follows: The flushing pump and valve of the next tower section of the tower section where the desorbent D is located are closed, the feed pipeline of the desorbent D is opened, the D feed pipeline of the original desorbent feed tower section is closed, and the flushing pump and valve are opened. The flushing pump and valve of the next tower section of the tower section where the extract E is located are closed, the discharge pipeline of the extract E is opened, the E discharge pipeline of the original extract discharge tower section is closed, and the flushing pump and valve are opened. The flushing pump and valve of the next tower section of the tower section where the raw material F is located are closed, the feed pipeline of the raw material F is opened, the F feed pipeline of the original raw material feed tower section is closed, and the flushing pump and valve are opened. The flushing pump and valve of the next tower section of the tower section where the raffinate R is located are closed, the discharge pipeline of the raffinate R is opened, the R discharge pipeline of the original raffinate tower section is closed, and the flushing pump and valve are opened.

[0134] Table 1 Inlet and outlet materials of each tower section in different steps

[0135]

[0136] It should be noted that the "inlet and outlet materials of each tower section" actually refers to the inlet and outlet materials in the fluid distributors of each tower section. In Table 1, D represents the feed desorbent in this tower section, C represents the flushing process in the tower section, E represents the extracted extract in this tower section, F represents the feed raw material in this tower section, and R represents the extracted raffinate in this tower section. The tower sections are numbered in the order from top to bottom.

[0137] The adsorption system of the present invention connects the four inlet and outlet materials and one circulating flushing material in the simulated moving bed to the same pipeline. When inlet and outlet materials are required, the flushing pump of the flushing pipeline is stopped. When this tower section does not require inlet and outlet materials, the flushing pump of the flushing pipeline is opened. A stream of material is led out from the fluid mixing chamber of this tower section, passes through the flushing pump and the inlet and outlet material pipeline, and then returns to the fluid mixing chamber of this tower section. This method can simplify the inlet and outlet material pipelines and the flushing process, reduce the disturbance of the materials in the adsorption tower, improve the separation performance of the adsorption tower, increase the output and reduce the energy consumption of the device.

[0138] The simulated moving bed adsorption separation system and method provided by the present invention can be applied to the separation of C8 aromatic hydrocarbon isomers and can also be applied to the separation of normal and isoparaffins. When using the simulated moving bed adsorption separation system to separate components such as C8 aromatic hydrocarbon isomers and normal and isoparaffins, each bed layer has four inlet and outlet materials and one flushing material, further reducing the number of control valves on the bed layer pipeline and simplifying the flushing process operation.

[0139] Example 1

[0140] Use the simulated moving bed process to separate p-xylene PX from mixed xylene. The simulated moving bed adsorption system is as Figure 5 shown, including 2 adsorption towers, which are connected in series. Each adsorption tower includes 12 tower sections, with 6 tower sections in the adsorption zone, 5 tower sections in the desorption zone, 10 tower sections in the purification zone, and 3 tower sections in the buffer zone. Each tower section includes a fluid distributor and an adsorbent bed layer, and the fluid distributor is located above the adsorbent bed layer. The structure of each adsorption tower is as Figure 1 shown, and a bottom collector is provided at its bottom.

[0141] The positions of the raw material F, desorbent D, extract E, and raffinate R have been marked in Figure 1 (valves are connected to the introduction pipeline 6 of the raw material F, the introduction pipeline 7 of the desorbent D, the export pipeline 8 of the extract E, and the export pipeline 6 of the raffinate R, Figure 1 not shown in Figure 2 . At most one of these valves is opened during one step period for each tower section for the feeding or discharging of one material), and the pipeline flushing method shown in

[0142] is adopted: the material is led out from the upper layer of the mixing chamber of the fluid distributor from the ports of the inlet and outlet material pipelines to flush the inlet and outlet material pipelines, and the flushed material is introduced into the lower layer of the mixing chamber of the fluid distributor through the flushing pipeline.

[0143] The entire adsorption separation system includes 24 tower sections. Each tower section includes 1 inlet and outlet material pipeline (for feeding and discharging 4 materials) and one flushing pipeline. A total of 24 flushing pumps are required, and the flow rates of the flushing pumps are all controlled by flow controllers.

[0144] One step time is 80 s and one cycle period is 32 min.

[0145] The working process of this embodiment is as follows:

[0146] At the first step, the desorbent D feed pipeline 7 of tower section ① is opened (i.e., the corresponding valve is opened, the same below), the extract E discharge pipeline 8 of tower section ⑥ is opened, the raw material F feed pipeline 6 of tower section is opened, the raffinate R discharge pipeline 5 of tower section is opened, and for the remaining tower sections, the flushing pump 12, valves 10 and 11 are opened, and the valves of the desorbent D feed pipeline 7, the extract E discharge pipeline 8, the raw material F feed pipeline 6 and the raffinate R discharge pipeline 5 are closed, and the flushing time is 80 s for all.

[0147] At the second step, the flushing pump of tower section ② is closed, the desorbent D feed pipeline 7 of tower section 2 is opened, the flushing pump 12, valves 10 and 11 of tower section ① are opened, and the valves of the desorbent D feed pipeline 7, the extract E discharge pipeline 8, the raw material F feed pipeline 6 and the raffinate R discharge pipeline 5 are closed; the flushing pump 12 of tower section ⑦ is closed, the extract E discharge pipeline 8 of tower section ⑦ is opened for discharging, the flushing pump 12, valves 10 and 11 of tower section ⑥ are opened, and the valves of the desorbent D feed pipeline 7, the extract E discharge pipeline 8, the raw material F feed pipeline 6 and the raffinate R discharge pipeline 5 are closed; the flushing pump of tower section is closed, the raw material F feed pipeline 6 of tower section is opened, the flushing pump 12, valves 10 and 11 of tower section are opened, and the valves of the desorbent D feed pipeline 7, the extract E discharge pipeline 8, the raw material F feed pipeline 6 and the raffinate R discharge pipeline 5 are closed; the flushing pump of tower section is closed, the raffinate R discharge pipeline 5 of tower section is opened, the flushing pump 12, valves 10 and 11 of tower section are opened, and the valves of the desorbent D feed pipeline 7, the extract E discharge pipeline 8, the raw material F feed pipeline 6 and the raffinate R discharge pipeline 5 are closed;

[0148] It should be noted that the tower sections are numbered in the order from top to bottom.

[0149] And so on, the opening and closing operations of the material inlet and outlet pipelines and the flushing pumps of each tower section within each step time are carried out.

[0150] The parameter results of the p-xylene purity, yield and solvent / oil ratio D / F in the extract E are shown in Table 2 in the appendix.

[0151] Example 2

[0152] Adopt the operation of Example 1 and use Figure 3The pipeline flushing method shown: Extract materials from the lower layer of the mixing chamber of the fluid distributor through the port of the flushing pipeline, flush the pipeline for feeding and discharging materials, and introduce the flushed materials into the upper layer of the mixing chamber of the fluid distributor.

[0153] The parameter results of the p-xylene purity, yield, and agent / oil ratio D / F in the extract E are shown in Table 2 in the appendix.

[0154] Example 3

[0155] Adopt the operation of Example 1, set the pipeline flushing time of the next tower section where the raw material F, desorbent D, extract E, and raffinate R are located to 80 s, and set the flushing pump not to be turned on for 0 - 40 s and turned on for 40 - 80 s for other tower sections.

[0156] Example 4

[0157] Adopt the operation of Example 2, set the pipeline flushing time of the next tower section where the raw material F, desorbent D, extract E, and raffinate R are located to 80 s, and set the flushing pump not to be turned on for 0 - 40 s and turned on for 40 - 80 s for other tower sections.

[0158] Comparative Example 1

[0159] The simulated moving bed system of this comparative example includes: 2 adsorption towers, each adsorption tower has 12 adsorbent beds (a total of 24 beds) and 13 grids (top and bottom grids and 11 intermediate bed grids), raw material F, desorbent D, raffinate R, extract E, and four flushing material flows C1, C2, C3, and C4. Among them, there are 6 beds in the desorption zone, 5 beds in the desorption zone, 10 beds in the purification zone, and 3 beds in the buffer zone. The operating temperature is 177 °C, the operating pressure is 0.88 MPa, the raw material is mixed xylene, in which p-xylene is 22.18% by mass, o-xylene is 20.44% by mass, m-xylene is 51.67% by mass, ethylbenzene is 4.94% by mass, a small amount of toluene is 0.53% by mass, and a small amount of non-aromatics is 0.22% by mass. The desorbent is p-diethylbenzene with a purity of 99.27% by mass. Use the desorbent as the primary flushing material flow C1 and inject it into the second bed layer upstream of the extract sampling point; use the extract E as the secondary flushing material flow C2 and inject it into the second bed layer downstream of the extract sampling point; use the extract E as the tertiary flushing material flow C3 and inject it into the second bed layer upstream of the raw material injection point; use the raw material F as the quaternary flushing material flow C4 and inject it into the second bed layer upstream of the raffinate sampling point. The stepping time of one bed layer is 80 s, and one cycle period is 32 min.

[0160] The comparison results of parameters such as the p-xylene product purity, yield, and D / F ratio (desorbent / raw material ratio) separated by the above adsorption separation process are shown in Table 2 in the appendix.

[0161] Table 2 Comparison of p-Xylene Product Purity, Yield and D / F Ratio between Examples and Comparative Examples

[0162] Product purity Product yield D / F ratio Example 1 99.87％ 99.1％ 1.1 Example 2 99.85％ 98.0％ 1.1 Example 3 99.83％ 97.5％ 1.1 Example 4 99.80％ 97.3％ 1.1 Comparative example 1 99.72％ 95.0％ 1.3

[0163] From the comparison results of the data of the examples and comparative examples in Table 2, it can be seen that by using the pipeline flushing method provided by the present invention, the product purity and product yield can be effectively improved, the separation performance of the adsorption tower can be improved, and the D / F (desorbent / raw material) ratio can be significantly reduced, and the desorbent consumption can be reduced.

[0164] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc. is the orientation or positional relationship based on the working state of the present application. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0165] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0166] The above has described the present application in combination with preferred embodiments. However, these embodiments are only exemplary and only serve an illustrative role. On this basis, various substitutions and improvements can be made to the present application, and these all fall within the protection scope of the present application.

Claims

1. A feed flushing device for a simulated moving bed, comprising: A fluid distributor, wherein the fluid distributor is arranged inside the simulated moving bed, and the fluid distributor includes: An upper surface support member having a channel for fluid to pass through, A lower surface fluid distribution member having a channel for fluid to pass through, A partition plate horizontally extending through the cross-sectional area of the fluid distributor, the partition plate separating the inner chamber of the fluid distributor formed by the upper surface support member and the lower surface fluid distribution member into an upper compartment and a lower compartment, the upper compartment being a fluid collection chamber and the lower compartment being a fluid distribution chamber; A mixing chamber arranged inside the fluid distributor, the upper layer of the mixing chamber being in fluid communication with the fluid collection chamber, and the lower layer of the mixing chamber being in fluid communication with the fluid distribution chamber, so that the external fluid entering the fluid collection chamber enters the fluid distribution chamber after passing through the mixing chamber and is discharged from the fluid distributor through the lower surface fluid distribution member; A circulation pipeline, the circulation pipeline including: An inlet and outlet material pipeline connected to the upper layer of the mixing chamber; A flushing pipeline connected to the lower layer of the mixing chamber; A flushing pump connected to the inlet and outlet material pipeline and the flushing pipeline.

2. The feed flushing device according to claim 1, wherein, A first control valve is arranged between the connection port of the inlet and outlet material pipeline and the upper layer of the mixing chamber and the flushing pump; a second control valve is arranged between the connection port of the flushing pipeline and the lower layer of the mixing chamber and the flushing pump.

3. The feeding and flushing device according to claim 1, wherein, A flow controller is also arranged in the circulation pipeline.

4. The feed flushing device according to claim 1, wherein, A part of the flushing pipeline is sleeved inside the inlet and outlet material pipeline.

5. The feed flushing device according to claim 1, wherein, The flushing pipeline and the inlet and outlet material pipeline are arranged side by side.

6. The feed flushing device according to claim 1, wherein, The size of the flushing pipeline is not larger than the size of the inlet and outlet material pipeline.

7. The feed flushing device according to claim 1, wherein, The following are also arranged on the inlet and outlet material pipeline: A raw material inlet communicating with the raw material feed pipeline, A desorbent inlet communicating with the desorbent feed pipeline, An extract discharge port communicating with the extract discharge pipeline, and A raffinate discharge port communicating with the raffinate discharge pipeline.

8. A simulated moving bed adsorption separation system, including an adsorption tower, the adsorption tower including a plurality of tower sections, each tower section including a fluid distributor and an adsorbent bed layer; Among them, Inside the adsorption tower, the fluid distributors and the adsorbent bed layers of each tower section are arranged alternately; Wherein, the fluid distributor of each tower section includes: An upper surface support member having a channel for fluid to pass through, A lower surface fluid distribution member having a channel for fluid to pass through, A partition plate horizontally extending through the cross-sectional area of the fluid distributor, the partition plate separating the inner chamber of the fluid distributor formed by the upper surface support member and the lower surface fluid distribution member into an upper compartment and a lower compartment, the upper compartment being a fluid collection chamber and the lower compartment being a fluid distribution chamber; A mixing chamber arranged inside the fluid distributor, the upper layer of the mixing chamber being in fluid communication with the fluid collection chamber, and the lower layer of the mixing chamber being in fluid communication with the fluid distribution chamber, so that the external fluid entering the fluid collection chamber enters the fluid distribution chamber after passing through the mixing chamber and is discharged from the fluid distributor through the lower surface fluid distribution member; Among them, the fluid distributors of each tower section are also connected with a circulation pipeline, and the circulation pipeline includes: An inlet and outlet material pipeline, which is connected to the upper layer of the mixing chamber; A flushing pipeline, which is connected to the lower layer of the mixing chamber; A flushing pump, which is communicated with the inlet and outlet material pipeline and the flushing pipeline; Among them, the following are also provided on the inlet and outlet material pipeline: A raw material inlet communicating with the raw material feed pipeline, A desorbent inlet communicating with the desorbent feed pipeline, An extract discharge port communicating with the extract discharge pipeline, and A raffinate discharge port communicating with the raffinate discharge pipeline.

9. The simulated moving bed adsorption separation system according to claim 8, wherein, A first control valve is provided between the connection port of the inlet and outlet material pipeline and the upper layer of the mixing chamber and the flushing pump; a second control valve is provided between the connection port of the flushing pipeline and the lower layer of the mixing chamber and the flushing pump; A flow controller is also provided in the circulation pipeline.

10. The simulated moving bed adsorption separation system according to claim 8, wherein, A part of the flushing pipeline is sleeved inside the inlet and outlet material pipeline.

11. The simulated moving bed adsorption separation system according to claim 8, wherein, The flushing pipeline and the inlet and outlet material pipeline are arranged side by side.

12. The simulated moving bed adsorption separation system according to claim 8, wherein The size of the flushing pipeline is not greater than the size of the inlet and outlet material pipeline.

13. A method for flushing pipelines of a simulated moving bed adsorption separation system, and the pipeline flushing method is carried out in the simulated moving bed adsorption separation system of claim 9, The method includes: In the flushing step, the first control valve, the second control valve and the flushing pump are opened, and materials are led out from the upper layer of the mixing chamber of the fluid distributor through the port of the inlet and outlet material pipeline to flush the inlet and outlet material pipeline, and the flushed materials are introduced into the lower layer of the mixing chamber of the fluid distributor through the flushing pipeline; or, In the flushing step, the first control valve, the second control valve and the flushing pump are opened, and materials are led out from the lower layer of the mixing chamber of the fluid distributor through the port of the flushing pipeline to flush the inlet and outlet material pipeline, and the flushed materials are introduced into the upper layer of the mixing chamber of the fluid distributor.

14. The pipeline flushing method according to claim 13, wherein, The total volume of materials flowing through the flushing pipeline within the flushing step is greater than the sum of the volume of the inlet and outlet material pipeline, the volume of the flushing pipeline and the volume of the fluid distributor.

15. The pipeline flushing method according to claim 13, wherein, The time when the first control valve is in the open state is n times the flushing step time, and 0.2 ≤ n ≤ 1.

0.

16. The pipeline flushing method according to claim 13, wherein, The flow rate of the material in the flushing pipeline is 1 - 3 m / s.

17. A method for adsorption separation using a simulated moving bed adsorption separation system, and the method is carried out in the simulated moving bed adsorption separation system of claim 9, The method includes: 1) In the first step, raw materials are fed into the fluid distributors of several first tower sections, desorbent is fed into the fluid distributors of several second tower sections, extract is discharged from the fluid distributors of several third tower sections, raffinate is discharged from the fluid distributors of several fourth tower sections, and a flushing process is carried out in the fluid distributors of several fifth tower sections, The flushing process includes: The first control valve, the second control valve and the flushing pump are opened, and materials are led out from the upper layer of the mixing chamber of the fluid distributor through the port of the inlet and outlet material pipeline to flush the inlet and outlet material pipeline, and the flushed materials are introduced into the lower layer of the mixing chamber of the fluid distributor through the flushing pipeline; or, Open the first control valve, the second control valve and the flushing pump, draw materials from the lower layer of the mixing chamber of the fluid distributor through the port of the flushing pipeline, flush the incoming and outgoing material pipelines, and introduce the flushed materials into the upper layer of the mixing chamber of the fluid distributor; 2) In the next step, change the tray positions for feeding the raw material and the desorbent and discharging the extract and the raffinate, and change the tray position for performing the flushing process; 3) Repeat step 2) until all steps are completed.

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