Vacuum distillation system, sampling device of vacuum distillation column, and sampling method

Abstract

A vacuum distillation system, a sampling device of a vacuum distillation column, and a sampling method. The vacuum distillation column comprises a column body and a withdrawal pipeline. The sampling device comprises a sampling box and a sampling pipe, wherein the sampling box is filled with an inert gas, and the sampling pipe is provided with an inlet end portion and an outlet end portion; the inlet end portion is connected to the withdrawal pipeline; the sampling pipe can partially extend into the sampling box; and the outlet end portion is located in the sampling box. In the solution described above, sampling detection of an organic solvent is performed in the relatively closed sampling box by means of the sampling pipe, and the sampling box is further filled with the inert gas for protection, so that contamination of the organic solvent caused by an external environment during a sampling process can be reduced, thereby improving the accuracy of a sampling test result, and facilitating accurate determination of the condition of the organic solvent in the column body.

Description

A vacuum distillation system, a vacuum distillation column sampling device and sampling method Technical Field

[0001] This application relates to the field of chemical distillation technology, specifically to a vacuum distillation system, a sampling device for a vacuum distillation column, and a sampling method. Background Technology

[0002] High-purity organic solvents are commonly used in the pharmaceutical and electronics industries. Taking the electronics industry as an example, organic solvents play a crucial role as raw materials, solvents, and cleaning agents in the precursor manufacturing process, and their purity directly affects semiconductor manufacturing processes.

[0003] Due to the tendency of organic solvents to decompose and polymerize at high temperatures, ordinary normal-pressure distillation cannot meet the required standards. Therefore, vacuum distillation is an indispensable step in the purification process of organic solvents. Specifically, it involves reducing the pressure of the distillation column to lower the temperature during separation, preventing product decomposition and polymerization. During vacuum distillation, real-time sampling and analysis of the product from the distillation column are necessary to determine its quality and control the distillation process. In conventional methods, vacuum distillation sampling is typically performed in a relatively open environment, making the sampling process susceptible to contamination, which can affect the accuracy of the sampling and testing, hindering accurate determination of product quality.

[0004] Therefore, how to provide a solution to overcome or alleviate the above-mentioned defects remains a technical problem that urgently needs to be solved by those skilled in the art.

[0005] Summary of the Invention

[0006] The purpose of this application is to provide a vacuum distillation system, a sampling device for a vacuum distillation column, and a sampling method. The sampling device can reduce the contamination of organic solvents by the external environment during the sampling process, which is beneficial to improving the accuracy of the sampling test results.

[0007] To solve the above-mentioned technical problems, this application provides a sampling device for a vacuum distillation column. The vacuum distillation column includes a column body and a collection pipeline. The sampling device includes a sampling box and a sampling tube. The sampling box is filled with an inert gas. The sampling tube has an inlet end and an outlet end. The inlet end is connected to the collection pipeline. The sampling tube can partially extend into the sampling box. The outlet end is located in the sampling box.

[0008] Using the above scheme, the sampling and testing of organic solvents is carried out through sampling tubes in a relatively sealed sampling box, which is also filled with inert gas for protection. This reduces the contamination of organic solvents by the external environment during the sampling process, thereby improving the accuracy of the sampling test results and helping to accurately determine the status of organic solvents in the tower body.

[0009] Optionally, it further includes a first switching valve, a second switching valve, a purge line, and a suction line. The first switching valve is used to regulate the connection between the inlet end and the sampling line. The second switching valve is used to regulate the opening and closing state of the outlet end. The purge line and the suction line are both connected to the sampling tube. The purge line is used to provide purge gas to the sampling tube, and the suction line is used to suction the sampling tube.

[0010] Optionally, the purging line is provided with a third switching valve and a check valve, with the check valve located on the side of the third switching valve closer to the sampling tube.

[0011] Optionally, the purging gas is nitrogen or an inert gas.

[0012] Optionally, the suction line is equipped with a fourth switching valve.

[0013] Optionally, it also includes a heating element that covers the outside of the sampling tube.

[0014] Optionally, the system also includes a support frame disposed inside the sampling box, wherein the sampling tube, the purge line, and the suction line are all mounted on the support frame.

[0015] Optionally, the sampling box is located below the sampling pipeline.

[0016] Optionally, it also includes a pressure detection component, which is installed in the sampling tube and used to detect the pressure inside the sampling tube.

[0017] This application also provides a vacuum distillation system, including a vacuum distillation column and a sampling device. The vacuum distillation column includes a column body and a collection pipeline, and the sampling device is the sampling device of the vacuum distillation column described above.

[0018] Optionally, the extraction pipeline is provided with a fifth switch valve and a sixth switch valve at intervals, and the section of the extraction pipeline located between the fifth switch valve and the sixth switch valve is connected to the sampling pipe.

[0019] This application also provides a sampling method for a vacuum distillation column, applicable to the sampling device of the aforementioned vacuum distillation column. The sampling method includes the following steps: a first purging step, controlling the closure of the first and second switching valves, controlling the purging pipeline to supply purging gas to the sampling tube, and controlling the suction pipeline to suction the sampling tube; a sampling step, controlling the purging pipeline to close and controlling the opening of the suction pipeline to lower the pressure in the sampling tube to a first set pressure, then controlling the purging pipeline to close, then controlling the opening of the first switching valve, and continuing for a set time; a sample discharge step, controlling the closure of the first switching valve, then controlling the opening of the purging pipeline to raise the pressure in the sampling tube to a second set pressure, the second set pressure being greater than the internal pressure of the sampling chamber, then controlling the purging pipeline to close, and then controlling the opening of the second switching valve.

[0020] Optionally, the control of the purge line to supply purge gas to the sampling tube and the control of the suction line to suction the sampling tube are performed simultaneously; or, the control of the purge line to supply purge gas to the sampling tube is performed before the control of the suction line to suction the sampling tube.

[0021] Optionally, the first set pressure is consistent with the internal pressure of the tower body.

[0022] Optionally, after the sample discharge step, the method further includes: a second purging step, which involves controlling the closure of the second switch valve, controlling the heating of the sampling tube, controlling the purging line to supply purging gas to the sampling tube, and controlling the suction line to suction the sampling tube. Attached Figure Description

[0023] Figure 1 is a schematic diagram of the structure of the vacuum distillation system provided in the embodiment of this application;

[0024] Figure 2 is a schematic diagram of the sampling device of the vacuum distillation column provided in the embodiment of this application;

[0025] Figure 3 is a schematic flowchart of the sampling method of the vacuum distillation column provided in the embodiments of this application.

[0026] Marker explanation:

[0027] 100 - Reduced pressure distillation column; 110 - Column body; 120 - Outlet pipeline; 121 - Fifth switch valve; 122 - Sixth switch valve; 123 - Filling drain; 130 - Reflux ratio controller;

[0028] 200 - Sampling device; 210 - Sampling box; 220 - Sampling tube; 221 - First switching valve; 222 - Second switching valve; 223 - Pressure detection component; 230 - Purge pipeline; 231 - Third switching valve; 232 - Check valve; 233 - First auxiliary pipeline; 240 - Suction pipeline; 241 - Fourth switching valve; 242 - Second auxiliary pipeline; 250 - Heating component; 260 - Support; 270 - Frame. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solutions of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] In the embodiments of this application, the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," "third," "fourth," "fifth," and "sixth" may explicitly or implicitly include one or more of that feature.

[0031] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection" and "linking" should be interpreted broadly. For example, "linking" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0032] In the description of embodiments of this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0033] Please refer to Figures 1 and 2. Figure 1 is a schematic diagram of the structure of the vacuum distillation system provided in the embodiment of this application; Figure 2 is a schematic diagram of the structure of the sampling device of the vacuum distillation column provided in the embodiment of this application.

[0034] As shown in Figures 1 and 2, this application provides a vacuum distillation system, including a vacuum distillation column 100, which may include a column body 110 and a collection pipeline 120.

[0035] The column body 110 is the main reaction site for vacuum distillation of organic solvents, used to improve the purity of the organic solvents. During production operations, the pressure inside the column body 110 is typically low, which reduces the decomposition and polymerization of the organic solvents during purification, thus ensuring the purification effect. Here, the embodiments of this application do not limit the specific value of the pressure inside the column body 110 during production operations. In practical applications, those skilled in the art can set it according to specific needs, as long as it meets the production requirements.

[0036] The column body 110 is also equipped with a reflux ratio controller 130, which may be located at the top of the column body 110. A collection line 120 may be connected to the reflux ratio controller 130 to collect the organic solvent within the column body 110 via the reflux ratio controller 130. A filling drain 123 may be provided at the end of the collection line 120 away from the reflux ratio controller 130 for discharging the organic solvent collected by the collection line 120.

[0037] In practical applications, before extracting the organic solvent from the tower body 110 through the extraction pipeline 120, it is necessary to test the purity and other relevant parameters of the organic solvent to determine whether the quality of the organic solvent meets the standards.

[0038] In this embodiment of the application, the vacuum distillation system is further equipped with a sampling device 200, which includes a sampling box 210 and a sampling tube 220.

[0039] The sampling chamber 210 is a sealed container filled with inert gas to ensure a suitable internal environment. The amount of inert gas in the sampling chamber 210 is not limited, meaning the gas pressure inside is not limited. In practical applications, those skilled in the art can set it according to specific needs. For example, the gas pressure inside the sampling chamber 210 can be set between 100 Pa and 200 Pa.

[0040] The sampling tube 220 has an inlet end and an outlet end. Referring to the orientation and positional relationship in Figures 1 and 2, the inlet end can specifically be the upper end of the sampling tube 220, and the outlet end can specifically be the lower end of the sampling tube 220. The inlet end is connected to the sampling pipeline 120, and the sampling tube 220 can partially extend into the sampling box 210, while the outlet end is located in the sampling box 210.

[0041] With this setup, the sampling and testing of organic solvents are carried out through the sampling tube 220 in a relatively sealed sampling box 210, which is also filled with inert gas for protection. This reduces the contamination of organic solvents by the external environment during the sampling process, thereby improving the accuracy of the sampling test results and helping to accurately determine the condition of organic solvents in the tower body 110.

[0042] To facilitate sampling by the sampling tube 220, a fifth switching valve 121 and a sixth switching valve 122 can also be configured on the sampling pipeline 120. The fifth switching valve 121 can be closer to the reflux ratio controller 130 than the sixth switching valve 122. Both the fifth switching valve 121 and the sixth switching valve 122 can be bidirectional guide valves, and their specific types are not limited here. In addition, the embodiments of this application do not limit the connection method between the fifth switching valve 121 and the sixth switching valve 122 and the pipeline in the sampling pipeline 120. In practical applications, those skilled in the art can select according to specific needs, as long as the requirements of use are met. For example, the fifth switching valve 121 and the sixth switching valve 122 can be connected to the pipeline using VCR, etc. It should be understood that the limitations on the installation method of the fifth switching valve 121 and the sixth switching valve 122 here also apply to the switching valves that appear in the following embodiments of this application. Therefore, this will not be described separately in the subsequent switching valves.

[0043] The inlet end of the sampling tube 220 can be connected to the section of the product pipeline 120 located between the fifth switch valve 121 and the sixth switch valve 122. During sampling, the sixth switch valve 122 can be closed and the fifth switch valve 121 opened. This allows the organic solvent within the column body 110 to flow into the sampling tube 220 under the action of the reflux ratio controller 130. At the end of sampling, the fifth switch valve 121 can be closed to isolate the reflux ratio controller 130 from the product pipeline 120.

[0044] In actual assembly, the fifth switching valve 121 can be positioned as close as possible to the reflux ratio controller 130, and the sixth switching valve 122 can also be positioned as close as possible to the fifth switching valve 121. That is, the pipeline between the reflux ratio controller 130 and the sixth switching valve 122 can be as short as possible, so that more organic solvent sample collected from the reflux ratio controller 130 can flow directly into the sampling tube 220, reducing waste. Here, this embodiment does not limit the distance between the fifth switching valve 121 and the reflux ratio controller 130, or the distance between the sixth switching valve 122 and the fifth switching valve 121. In practical applications, those skilled in the art can determine these distances based on specific needs, as long as the requirements are met.

[0045] In some alternative implementations, as shown in Figures 1 and 2, the sampling device 200 provided in the embodiments of this application may further include a first switching valve 221, a second switching valve 222, a purge line 230, and a suction line 240.

[0046] The first switching valve 221 is used to regulate the connection between the inlet end and the sampling pipeline 120. The first switching valve 221 can be located within the sampling pipe 220, as shown in Figures 1 and 2. In this case, the first switching valve 221 can be a two-way valve. Alternatively, the first switching valve 221 can be located between the sampling pipeline 120 and the sampling pipe 220; in this case, the first switching valve 221 can be a three-way valve. In short, the first switching valve 221 only needs to regulate the connection between the sampling pipe 220 and the sampling pipeline 120. The second switching valve 222 can be a two-way valve, used to regulate the opening and closing state of the outlet end. The specific types of the first switching valve 221 and the second switching valve 222 are not limited here.

[0047] Both the purge line 230 and the suction line 240 can be connected to the sampling tube 220, specifically to the section of the sampling tube 220 between the first switching valve 221 and the second switching valve 222. The purge line 230 provides purge gas to the sampling tube 220, such as nitrogen or other inert gases. The suction line 240 is used to suction gas from the sampling tube 220.

[0048] Before sampling, the first switch valve 221 and the second switch valve 222 can be closed, and then the purge line 230 and the suction line 240 can be opened. The purge line 230 can continuously supply purge gas into the sampling tube 220 to purge the inside of the sampling tube 220, while the suction line 240 can suction the gas inside the sampling tube 220, thereby replacing the substances inside the sampling tube 220 and ensuring the cleanliness of the inside of the sampling tube 220.

[0049] In some designs, the purge line 230 and the suction line 240 can be opened simultaneously. In this case, while purge gas continuously flows into the sampling tube 220 through the purge line 230, gas is also continuously discharged through the suction line 240; the intake and exhaust can occur synchronously. The continuous operating time of the purge line 230 and the suction line 240 is not limited here.

[0050] In other solutions, an in-feed, out-feed approach can be adopted. First, a certain amount of purge gas is introduced into the sampling tube 220 through the purge line 230. Then, the gas in the sampling tube 220 is suctioned through the suction line 240. In this embodiment, one inlet and one outlet constitute one purge cycle. In practical applications, the number of times the purge cycle is executed, as well as the inlet and outlet times within a single purge cycle, are not limited.

[0051] After completing the aforementioned purging and cleaning of the sampling tube 220, further suction can be performed inside the sampling tube 220 via the suction line 240 to reduce the pressure inside the sampling tube 220, thereby facilitating the flow of organic solvent into the sampling tube 220. In specific implementation, the pressure inside the sampling tube 220 can be controlled to be consistent with that of the column body 110. In this way, the impact on the internal pressure of the column body 110 can be reduced during sampling, and the pressure balance inside the column body 110 will not be disrupted, which is conducive to ensuring the normal operation of the column body 110.

[0052] During sampling, the first switch valve 221 and the fifth switch valve 121 can be opened, and the sixth switch valve 122, the purge line 230, the suction line 240 and the second switch valve 222 can be closed, so that the organic solvent can be introduced into the sampling tube 220 by the reflux ratio controller 130.

[0053] At the end of sampling, the first switch valve 221 and the fifth switch valve 121 can be closed, and then the purge line 230 can be opened to purge gas into the sampling tube 220 again, thereby increasing the pressure inside the sampling tube 220 so that the pressure inside the sampling tube 220 can be greater than the pressure inside the sampling box 210, so as to facilitate the discharge of organic solvents from the sampling tube 220.

[0054] As can be seen from the above process, the sampling device 200 provided in this application embodiment only needs to control the corresponding switching valve to open and close when in use, and the operation is simple.

[0055] In actual assembly, the sampling box 210 can be located below the sampling pipeline 120, and the sampling tube 220 can extend vertically. In this way, the flow of organic solvent to the sampling tube 220 can be easily achieved by utilizing the difference in gravity.

[0056] In some alternative implementations, the sampling tube 220 may also be equipped with a pressure detection component 223, which can be used to detect the pressure inside the sampling tube 220 so as to accurately control the pressure condition inside the sampling tube 220.

[0057] For example, during the aforementioned purging procedure, when purging gas is introduced into the sampling tube 220 through the purging line 230, the pressure detection component 223 can detect the pressure value inside the sampling tube 220 to determine the end point of the gas intake. The specific pressure value at the end point of the gas intake is not limited here. Similarly, when the sampling tube 220 is suctioned through the suction line 240, the pressure detection component 223 can also detect the pressure value inside the sampling tube 220 to determine the end point of the gas exhaust. The specific pressure value at the end point of the gas exhaust is not limited here.

[0058] For example, after completing the aforementioned purging and cleaning of the inside of the sampling tube 220, when reducing the pressure inside the sampling tube 220 through the suction line 240, the pressure detection component 223 can detect the pressure value inside the sampling tube 220 to reduce the pressure inside the sampling tube 220 to a first set pressure, facilitating the flow of organic solvent into the sampling tube 220. This first set pressure can specifically be consistent with the pressure inside the tower body 110.

[0059] For example, after sampling, when the pressure inside the sampling tube 220 is increased through the purge line 230, the pressure detection component 223 can detect the pressure value inside the sampling tube 220 to increase the pressure inside the sampling tube 220 to a second set pressure, which facilitates the discharge of organic solvent from inside the sampling tube 220. This second set pressure can be greater than the pressure inside the sampling box 210.

[0060] In some alternative implementations, the purge line 230 may be equipped with a third switching valve 231, a check valve 232, and a first auxiliary pipeline 233.

[0061] The third switching valve 231 can be a two-way valve, used to regulate the opening and closing of the purge line 230. The check valve 232 and the third switching valve 231 can be installed on the pipeline between the first auxiliary pipeline 233 and the sampling pipe 220, wherein the check valve 232 can be located on the side of the third switching valve 231 closer to the sampling pipe 220. The check valve 232 is a one-way valve, used to reduce the possibility of gas in the sampling pipe 220 flowing back into the first auxiliary pipeline 233.

[0062] The first auxiliary pipeline 233 is used to supply purge gas. Taking nitrogen as an example, the pressure in the first auxiliary pipeline 233 can be maintained between 200 Pa and 500 Pa.

[0063] In some alternative implementations, the suction line 240 may be equipped with a fourth switching valve 241 and a second auxiliary pipeline 242. The fourth switching valve 241 is a bidirectional valve used to regulate the opening and closing of the suction line 240. The second auxiliary pipeline 242 is a vacuum pipeline used to provide suction force to the sampling tube 220.

[0064] In this embodiment, the sampling tube 220, the first auxiliary pipe 233, and the second auxiliary pipe 242 all need to pass through the wall of the sampling box 210. A sealing component can be provided at the point of penetration to ensure the airtightness of the sampling box 210. This sealing component can be, for example, a sealing ring or sealing filler, etc., and is not specifically limited here.

[0065] In some optional implementations, the sampling device 200 provided in this application embodiment may further include a heating component 250, which may be, for example, an electric heating tape, which may cover the outside of the sampling tube 220 for heating the sampling tube 220.

[0066] Specifically, after the organic solvent in the sampling tube 220 is discharged into the sampling chamber 210, the first switch valve 221 and the second switch valve 222 can be closed. Then, the heating element 250 can be activated to heat the sampling tube 220, which helps to vaporize the organic solvent remaining on the inner wall of the sampling tube 220. The purge line 230 and the suction line 240 can be activated again to replace the substances inside the sampling tube 220, thereby improving the cleanliness of the sampling tube 220. This effectively removes residual organic solvent inside the sampling tube 220, reduces cross-contamination between adjacent sampling operations, and allows the sampling device 200 provided in this embodiment to continuously perform the extraction and detection of organic solvent samples. The start-up sequence of the purge line 230 and the suction line 240 can be referred to the above description and will not be repeated here; in addition, the start-up of the heating element 250 can be before the purge line 230 and the suction line 240, or it can be started simultaneously with the purge line 230 and the suction line 240, which is not limited here.

[0067] In practical applications, the inner walls of the sampling tube 220, the collection pipe 120, and each switch valve can be polished or otherwise surface-treated to meet the requirements of organic solvents for metal ions and other particulate matter. This also reduces the amount of organic solvent residue adhering to the walls of various components. The sampling tube 220 can be made of stainless steel EP tubing, which generally meets the requirements. The radial dimension of the sampling tube 220 can be between 1 / 2 and 1 / 4 of an inch, thus effectively controlling the amount of organic solvent sampled.

[0068] In some optional implementations, the sampling device 200 provided in this application embodiment may further include a bracket 260. As shown in Figures 1 and 2, the bracket 260 may be disposed inside the sampling box 210, and the sampling tube 220, the purge line 230, and the suction line 240 may all be installed on the bracket 260 to improve the installation reliability of the sampling tube 220, the purge line 230, and the suction line 240 inside the sampling box 210.

[0069] A frame 270 can be configured on the outside of the sampling box 210, which can be used to install and fix the sampling box 210.

[0070] The specific structural form of bracket 260 and rack 270 is not limited here, as long as it can meet the actual use requirements.

[0071] Please refer to Figure 3, which is a schematic flowchart of the sampling method of the vacuum distillation column provided in the embodiment of this application.

[0072] As shown in Figure 3, this application embodiment also provides a sampling method for a vacuum distillation column 100, which is applicable to the sampling device 200 of the vacuum distillation column 100 involved in the aforementioned implementations. The sampling method includes at least the following first purging step S100, sampling step S200 and sample discharge step S300.

[0073] In the first purging step S100, the first switching valve 221 and the second switching valve 222 are closed, the purging pipeline 230 is controlled to supply purging gas to the sampling tube 220, and the suction pipeline 240 is controlled to suction the sampling tube 220. In this way, the gas inside the sampling tube 220 can be replaced, thereby improving the cleanliness of the sampling tube 220.

[0074] As mentioned earlier, the purge line 230 and the suction line 240 can be started simultaneously, allowing the sampling tube 220 to simultaneously receive and expel air. Alternatively, the purge line 230 can be opened before the suction line 240, allowing the sampling tube 220 to receive air first. When the pressure inside the sampling tube 220 reaches a certain value (detected and determined by the pressure detection component 223), the purge line 230 can be closed, and then the suction line 240 can be opened to suction the inside of the sampling tube 220. The endpoint of the suction can also be detected and determined by the aforementioned pressure detection component 223.

[0075] It should be understood that during the execution of the first purging step S100, both the fifth switch valve 121 and the sixth switch valve 122 of the extraction pipeline 120 are in the closed state.

[0076] In sampling step S200, the purge line 230 is closed and the suction line 240 is opened to reduce the pressure inside the sampling tube 220 to a first set pressure. Then, the suction line 240 is closed and the first switch valve 221 is opened and held for a set time. This depressurization process inside the sampling tube 220 facilitates the flow of organic solvent into the sampling tube 220.

[0077] In a specific example, the aforementioned first set pressure can be consistent with the internal pressure of the tower body 110. In this way, the pressure balance inside the tower body 110 will not be disrupted during the sampling process, and it is also beneficial to ensure the normal operation of the tower body 110.

[0078] It should be understood that during the execution of sampling step S200, the fifth switch valve 121 of the sampling pipeline 120 may be in the open state, while the sixth switch valve 122 may be in the closed state.

[0079] In sample discharge step S300, the first switch valve 221 is closed, and then the purge line 230 is opened to adjust the pressure inside the sampling tube 220 to a second set pressure, which is greater than the internal pressure of the sampling chamber 210. Then, the purge line 230 is closed, and then the second switch valve 222 is opened. This creates a pressure difference between the sampling tube 220 and the sampling chamber 210, which is more conducive to the discharge of organic solvent from the sampling tube 220.

[0080] In some optional implementations, the sampling method provided in this application embodiment may further include a second purging step S400 after the sample discharge step S300: controlling the closing of the second switching valve 222, controlling the heating of the sampling tube 220, controlling the purging pipeline 230 to provide purging gas to the sampling tube 220, and controlling the suction pipeline 240 to suction the sampling tube 220. This effectively removes residual organic solvent inside the sampling tube 220, reduces cross-contamination between adjacent sampling operations, and allows the sampling device 200 provided in this application embodiment to continuously perform the extraction and detection of organic solvent samples.

[0081] In the second purging step S230, the heating operation of the sampling tube 220 can occur before purging and suction. This way, during purging and suction, the organic solvent remaining on the inner wall of the sampling tube 220 has already vaporized, allowing for better removal of this residual substance. Of course, simultaneously performing the heating operation with purging and suction is also an option.

[0082] The above are merely preferred embodiments of this application. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A sampling device for a vacuum distillation column, characterized in that, The vacuum distillation column includes a column body and a collection pipeline. The sampling device includes a sampling box and a sampling tube. The sampling box is filled with inert gas. The sampling tube has an inlet end and an outlet end. The inlet end is connected to the collection pipeline. The sampling tube can partially extend into the sampling box. The outlet end is located in the sampling box.

2. The sampling device for the vacuum distillation column according to claim 1, characterized in that, It also includes a first switching valve, a second switching valve, a purge line, and a suction line. The first switching valve is used to regulate the connection between the inlet end and the sampling line. The second switching valve is used to regulate the opening and closing of the outlet end. The purge line and the suction line are both connected to the sampling tube. The purge line is used to provide purge gas to the sampling tube, and the suction line is used to suction the sampling tube.

3. The sampling device for the vacuum distillation column according to claim 2, characterized in that, The purging line is equipped with a third switching valve and a check valve, with the check valve located on the side of the third switching valve closer to the sampling tube.

4. The sampling device for the vacuum distillation column according to claim 2, characterized in that, The purging gas is nitrogen or an inert gas.

5. The sampling device for the vacuum distillation column according to claim 2, characterized in that, The suction line is equipped with a fourth switching valve.

6. The sampling device for the vacuum distillation column according to any one of claims 2-5, characterized in that, It also includes a heating element, which is wrapped around the outside of the sampling tube.

7. The sampling device for the vacuum distillation column according to any one of claims 2-5, characterized in that, It also includes a support frame, which is disposed inside the sampling box, and the sampling tube, the purge line and the suction line are all installed on the support frame.

8. The sampling device for the vacuum distillation column according to any one of claims 2-5, characterized in that, The sampling box is located on the lower side of the sampling pipeline.

9. The sampling device for the vacuum distillation column according to any one of claims 2-5, characterized in that, It also includes a pressure detection component, which is installed in the sampling tube and is used to detect the pressure inside the sampling tube.

10. A vacuum distillation system, characterized in that, The invention includes a vacuum distillation column and a sampling device. The vacuum distillation column includes a column body and a collection pipeline. The sampling device is the sampling device of the vacuum distillation column according to any one of claims 1-9.

11. The vacuum distillation system according to claim 10, characterized in that, The extraction pipeline is provided with a fifth switch valve and a sixth switch valve at intervals, and the section of the extraction pipeline located between the fifth switch valve and the sixth switch valve is connected to the sampling pipe.

12. A sampling method for a vacuum distillation column, characterized in that, The sampling device applicable to the vacuum distillation column according to any one of claims 2-9, the sampling method comprising the following steps: In the first purging step, the first and second switching valves are closed, the purging pipeline is controlled to supply purging gas to the sampling tube, and the suction pipeline is controlled to suction the sampling tube. The sampling process involves controlling the purging line to close and the suction line to open, thereby reducing the pressure in the sampling tube to a first set pressure. Then, the suction line is closed, and the first switch valve is opened and maintained for a set time. In the sample discharge step, the first switch valve is closed, and then the purge line is opened to increase the pressure in the sampling tube to a second set pressure, which is greater than the internal pressure of the sampling box. Then the purge line is closed, and then the second switch valve is opened.

13. The sampling method for the vacuum distillation column according to claim 12, characterized in that, The control of the purge line to supply purge gas to the sampling tube and the control of the suction line to suction the sampling tube are executed simultaneously; or... The control of the purge line to supply purge gas to the sampling tube precedes the control of the suction line to perform suction on the sampling tube.

14. The sampling method for the vacuum distillation column according to claim 12, characterized in that, The first set pressure is consistent with the internal pressure of the tower body.

15. The sampling method for a vacuum distillation column according to any one of claims 12-14, characterized in that, The sample removal step is followed by: In the second purging step, the second switch valve is closed, the sampling tube is heated, the purging pipeline provides purging gas to the sampling tube, and the suction pipeline suctions the sampling tube.

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