Closed sampling device and method for carboxylic butadiene-acrylonitrile latex

Abstract

The invention relates to the technical field of chemical engineering sampling equipment, in particular to a closed sampling device and method for carboxylic butadiene-acrylonitrile latex. The sampling device comprises a sampling part which comprises a root stop valve, a pin type sampling valve and a sampling pipe, and a discharge port of the root stop valve is communicated with a feed port of the pin type sampling valve; a discharging hole of the pin type sampling valve is communicated with a feeding hole of the sampling pipe; the sampling part comprises a sampling joint, a sampling buffer joint and a sampling bottle, a feed port of the sampling joint is communicated with a discharge port of the sampling tube, a discharge port of the sampling joint is communicated with a feed port of the sampling buffer joint, and a discharge port of the sampling buffer joint is communicated with the sampling bottle; the vacuum pump is communicated with the sampling buffer joint; according to the sampling device, the emulsion is almost fully filled in the extraction stage of the needle cylinder, and no foam is generated, so that the freshness of a sample and the instantaneity and the accuracy of detection data can be ensured, and meanwhile, the problems that high-viscosity carboxylic butadiene-acrylonitrile latex is poor in flowability and difficult to sample under a vacuum condition can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of chemical sampling equipment, and particularly relates to a closed sampling device and method for carboxy nitrile latex. Background Art

[0002] Carboxy nitrile latex is an aqueous latex with a solid content of 30% - 50% obtained by emulsion polymerization using butadiene, acrylonitrile, and methacrylic acid as raw materials. During the synthesis of carboxy nitrile latex, it is necessary to take samples and analyze them multiple times to judge the reaction progress, which is an essential production operation process in the production process and one of the extremely important means to ensure production safety. However, if a common sampling valve is used for closed sampling in the polymerization kettle for synthesizing carboxy nitrile latex, since the polymerization sample contains emulsifier, a large amount of foam will rapidly generate in the sampling bottle during sampling, which will cause difficulties in sampling. In addition, the sampling sample contains highly volatile raw materials such as butadiene and acrylonitrile, which will volatilize from the latex during sampling and be discharged with the waste gas, making it impossible to accurately reflect the reaction progress in the kettle during sample analysis and detection, and also bringing potential hazards to reaction control and production safety.

[0003] Carboxy nitrile latex needs to flash off the unreacted residual butadiene in a degassing kettle at a certain temperature, vacuum degree, and time, and this operation process also requires multiple analyses. The existing sampling method installs a drainage pipe downward on the equipment to make the material flow by gravity to the sampling bottle at a lower position. Due to the high viscosity of carboxy nitrile latex, this sampling method is not only slow, wastes a lot of samples, but also easily causes blockage of the pipeline and valve because the latex remains in the pipeline after sampling, and it is difficult to be used reliably for a long time. Summary of the Invention

[0004] The present application provides a closed sampling device and method for carboxy nitrile latex to solve the technical problems in the prior art that the sampling data of the polymerization kettle and the sample detection data of the degassing kettle are inaccurate and it is difficult to sample under vacuum conditions.

[0005] In a first aspect, the present application provides a closed sampling device for carboxy nitrile latex, and the sampling device includes:

[0006] A sampling part, the sampling part includes a root cut-off valve, a needle-type sampling valve, and a sampling pipe. The discharge port of the root cut-off valve is communicated with the feed port of the needle-type sampling valve, and the feed port of the root cut-off valve is used to collect carboxy nitrile latex; the discharge port of the needle-type sampling valve is communicated with the feed port of the sampling pipe;

[0007] A sampling part, the sampling part includes a sampling joint, a sampling buffer joint, and a sampling bottle. The feed port of the sampling joint is communicated with the discharge port of the sampling pipe, the discharge port of the sampling joint is communicated with the feed port of the sampling buffer joint, and the discharge port of the sampling buffer joint is communicated with the sampling bottle;

[0008] A vacuum pump, which is connected to the sampling buffer joint.

[0009] Optionally, the needle-type sampling valve includes a rubber gasket; a needle insertion port is provided on the rubber gasket to achieve immediate and accurate sampling of the needle-type sampling valve.

[0010] Optionally, the sampling section further includes a sampling ball valve. The feed port of the sampling ball valve is connected to the discharge port of the sampling pipe, and the discharge port of the sampling ball valve is connected to the feed port of the sampling joint.

[0011] Optionally, the sampling section further includes a shield. The two ends of the shield are respectively rotatably connected to the sampling buffer joint, and the bottom of the shield abuts against the bottom of the sampling bottle.

[0012] Optionally, the sampling device further includes:

[0013] A nitrogen pressure reducing valve, which is arranged at the discharge port of the sampling pipe. The intake port of the nitrogen pressure reducing valve is connected to a nitrogen generating device to form a nitrogen purging port.

[0014] Optionally, the sampling section further includes a hot water interface, which is arranged between the root cut-off valve and the needle-type sampling valve.

[0015] Optionally, the sampling section further includes an exhaust port, which is arranged on one side of the sampling joint to discharge sampling exhaust gas.

[0016] Optionally, the vacuum pump is connected to the sampling joint through the exhaust port.

[0017] Optionally, the bottle mouth of the sampling bottle is provided with a self-closing rubber stopper.

[0018] In a second aspect, the present application provides a method for hermetically sampling carboxy nitrile latex, and the method includes:

[0019] Sampling the carboxy nitrile latex in the polymerization kettle by using the sampling device described in the first aspect, and performing backflushing with nitrogen to obtain a sampling device containing the sample;

[0020] Inserting a sampler into the sampling device and performing sample extraction to obtain a sampling sample to be tested;

[0021] Performing backflushing on the sampling device, and then discharging the sampling exhaust gas to complete the sampling;

[0022] Or,

[0023] Vacuumizing the sampling device described in the first aspect, and then sampling the carboxy nitrile latex in the degassing kettle by using the sampling device to obtain a sampling device containing the sample;

[0024] Insert a sampler into the sampling device and extract a sample to obtain a sampling sample to be tested;

[0025] Blow back the sampling device, and then discharge the sampling exhaust gas to complete sampling.

[0026] The above technical solutions provided by the embodiments of the present application have the following advantages compared with the prior art:

[0027] A closed sampling device for carboxybutadiene latex provided by an embodiment of the present application, compared with the traditional syringe sampling method, through a sampling part including a root cut-off valve, a needle-inserting sampling valve and a sampling tube, combined with a sampling part including a sampling joint, a sampling buffer joint and a sampling bottle, by installing the root cut-off valve on the sampling equipment or sampling pipeline, it is possible to close the sampling channel in time at the end of sampling to avoid the possible leakage of dangerous materials during the production process. At the same time, the use of a needle-inserting sampling valve can not only avoid the leakage of dangerous materials during the sampling stage, but also facilitate the sampling of the needle head at the sampling port of the sampling valve. When the sampling object equipment is a polymerization kettle, due to the high pressure in the polymerization kettle, the carboxybutadiene latex can quickly enter the root cut-off valve and the needle-inserting sampling valve, and then enter the sampling bottle through the sampling joint and the sampling buffer joint, so that the entire sampling device is filled with carboxybutadiene latex. During the syringe extraction stage, the emulsion is almost completely filled, no foam is generated, and no gas escapes from the sample. Therefore, the freshness of the sample and the timeliness and accuracy of the detection data can be guaranteed; when the sampling object equipment is a degassing kettle, the device can form a negative pressure through a vacuum pump, and at this time, the carboxybutadiene latex in the degassing kettle can quickly enter the sampling bottle and fill the sampling device. Therefore, the problem that it is difficult to sample the high-viscosity carboxybutadiene latex under vacuum conditions due to poor fluidity can be solved, and during the syringe extraction stage, the emulsion is almost completely filled and no foam is generated. Therefore, the freshness of the sample and the timeliness and accuracy of the detection data can be guaranteed. Description of the Drawings

[0028] The drawings here are incorporated into the specification and constitute a part of this specification, showing the embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of a closed sampling device for carboxybutadiene latex provided by an embodiment of the present application;

[0031] Figure 2 It is a schematic flow chart of the closed sampling method for carboxybutadiene nitrile latex in the polymerization kettle provided by the embodiment of the present application;

[0032] Figure 3 It is a schematic flow chart of the closed sampling method for carboxybutadiene nitrile latex in the degassing kettle provided by the embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the existing closed sampling device for carboxybutadiene nitrile latex provided in Comparative Example 1 of the present application;

[0034] Among them, 1 - root cut-off valve, 2 - hot water interface, 3 - needle-type sampling valve, 4 - sampling pipe, 5 - nitrogen pressure reducing valve, 6 - sampling ball valve, 7 - sampling joint, 8 - shield, 9 - sampling bottle, 10 - vacuum pump, 11 - rubber gasket, 12 - sampling buffer joint, 13 - exhaust port. Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0036] Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the present application can be obtained through market purchase or can be prepared by existing methods.

[0037] As Figure 1 shown, the embodiment of the present application provides a closed sampling device for carboxybutadiene nitrile latex, and the sampling device includes:

[0038] A sampling part, the sampling part includes a root cut-off valve 1, a needle-type sampling valve 3 and a sampling pipe 4. The discharge port of the root cut-off valve 1 is communicated with the feed port of the needle-type sampling valve 3, and the feed port of the root cut-off valve 1 is used to collect carboxybutadiene nitrile latex; the discharge port of the needle-type sampling valve 3 is communicated with the feed port of the sampling pipe 4;

[0039] A sampling part, the sampling part includes a sampling joint 7, a sampling buffer joint 12 and a sampling bottle 9. The feed port of the sampling joint 7 is communicated with the discharge port of the sampling pipe 4, the discharge port of the sampling joint 7 is communicated with the feed port of the sampling buffer joint 12, and the discharge port of the sampling buffer joint 12 is communicated with the sampling bottle 9;

[0040] A vacuum pump 10, and the vacuum pump 10 is connected to the sampling buffer joint 12.

[0041] It should be noted that the material of the sampling tube 4 can be stainless steel, which can reduce the adhesion of carboxybutadiene rubber latex to the pipeline, thereby extending the service life of the sampling device.

[0042] It should be noted that each pipeline and each valve of the sampling device can be connected by a clamp, which facilitates the disassembly and replacement of each pipeline and each valve.

[0043] It should be noted that the sampling bottle 9 and the sampling buffer joint 12 can be connected by an insertion method or a screw connection method.

[0044] Exemplarily, the root cut-off valve 1 can be a full-bore ball valve or a gate valve.

[0045] Exemplarily, the needle-type sampling valve 3 can be an on-line direct-through needle-type sampling valve 3, and the needle-type sampling valve 3 can be closed by operating a handle or a handwheel, further reducing the possibility of leakage of dangerous materials.

[0046] Exemplarily, the sampling joint 7 can adopt a joint with a sampling needle. On the one hand, the sampling joint 7 can be connected to the sampling ball valve 6 by an insertion method, and then the sampling joint 7 can be connected to the sampling buffer joint 12 by an insertion method through the sampling buffer joint 12. On the other hand, the sampling needle can control the flow rate of carboxybutadiene rubber latex into the sampling bottle 9 to avoid foaming in the sample due to excessive flow rate.

[0047] Exemplarily, the sampling joint can be a ferrule assembly.

[0048] In some alternative embodiments, the needle-type sampling valve 3 includes a rubber gasket 11; an insertion port is provided on the rubber gasket 11 to achieve instant and accurate sampling of the needle-type sampling valve 3.

[0049] In the embodiment of the present application, by introducing the rubber gasket 11 and providing an insertion port on the rubber gasket 11, since the density of carboxybutadiene rubber latex is greater than the density of rubber and the viscosity of carboxybutadiene rubber latex is relatively large, it is difficult for carboxybutadiene rubber latex to leak from the insertion port. At the same time, during the syringe sampling stage, the syringe can draw enough carboxybutadiene rubber latex from the insertion port, so that the emulsion fills the syringe without foaming and volatilizable components overflowing. Therefore, the instantaneity and accuracy of the detection of carboxybutadiene rubber latex samples can be improved.

[0050] It should be noted that the rubber gasket 11 is a rubber gasket 11 that can be easily replaced. In order to ensure smooth sampling, the thickness of the rubber gasket 11 can be 1.5 mm to 3 mm.

[0051] In some alternative embodiments, the sampling unit further includes a sampling ball valve 6. The inlet of the sampling ball valve 6 is communicated with the outlet of the sampling pipe 4, and the outlet of the sampling ball valve 6 is communicated with the inlet of the sampling joint 7.

[0052] In the embodiments of the present application, by introducing the sampling ball valve 6, the opening and closing of the sampling bottle 9 can be controlled through the sampling ball valve 6, so as to facilitate the flushing and blowing, and facilitate the carboxybutadiene latex sample in the pipeline after flushing and blowing to enter the sampling bottle 9, improving the immediacy and accuracy of the detection of the carboxybutadiene latex sample.

[0053] In some alternative embodiments, the sampling unit further includes a shield 8. The two ends of the shield 8 are respectively rotatably connected to the sampling buffer joint 12, and the bottom of the shield 8 abuts against the bottom of the sampling bottle 9.

[0054] In the embodiments of the present application, by arranging the shield 8 in the sampling unit, the stable sampling of the sampling bottle 9 can be protected through the shield 8, and a fixed structure can also be formed to prevent the sampling bottle 9 from falling off.

[0055] In some alternative embodiments, the sampling device further includes:

[0056] A nitrogen pressure reducing valve 5, which is arranged at the outlet of the sampling pipe 4. The inlet of the nitrogen pressure reducing valve 5 is communicated with a nitrogen generating device to form a nitrogen flushing port.

[0057] In the embodiments of the present application, by arranging the nitrogen pressure reducing valve 5, a nitrogen flushing port is formed by using the nitrogen generating device and the nitrogen pressure reducing valve 5. After the syringe sampling is completed, most of the residual samples can be blown back into the sampling equipment or the process main pipeline through the nitrogen flushing port, which can prevent the blockage of the pipeline and valves by carboxybutadiene latex to a certain extent, and can also reduce the waste of samples during sampling.

[0058] It should be noted that the nitrogen generating device can be a nitrogen cylinder, a nitrogen production line or a nitrogen collection device.

[0059] It should be noted that in order to further control the flushing effect, the nitrogen pressure reducing valve 5 can be selected as a nitrogen pressure reducing valve 5 with a pressure gauge.

[0060] In some alternative embodiments, the sampling unit further includes a hot water interface 2, which is arranged between the root cut-off valve 1 and the needle insertion sampling valve 3.

[0061] In the embodiment of the present application, a hot water interface 2 is introduced into the sampling part, and hot water is introduced through the hot water interface 2 to flush the carboxyl nitrile latex sample after nitrogen purging, and the flushed carboxyl nitrile latex sample flows into the sampling bottle 9 by itself. Therefore, the carboxyl nitrile latex sample can be reduced from forming gel in the sampling tube 4 line or valve to block the pipeline and valve. In addition, it can also reduce the waste of samples in the sampling stage and reduce the detection cost.

[0062] In some optional embodiments, the sampling portion further includes an exhaust port 13, and the exhaust port 13 is provided on one side of the sampling connector 7 to discharge sampling waste gas.

[0063] In some optional embodiments, the vacuum pump 10 is connected to the sampling connector 7 through the exhaust port 13 .

[0064] In the embodiment of the present application, by introducing the exhaust port 13 in the sampling part, on the one hand, the exhaust port 13 can discharge the exhaust gas in the sampling bottle 9 into the sampling device when sampling in the polymerization kettle, and on the other hand, it can be used as the exhaust port of the vacuum pump 10 when sampling in the degassing kettle, so that negative pressure is formed in the sampling bottle 9. Therefore, sampling can be smoothly carried out in the degassing kettle sampling stage, which solves the problem of difficulty in sampling under vacuum conditions of the carboxylic nitrile latex degassing kettle, and improves the sampling efficiency as well as the timeliness and accuracy of the samples.

[0065] In some optional embodiments, the mouth of the sampling bottle 9 is provided with a self-closing rubber stopper.

[0066] In the embodiment of the present application, a self-closing rubber stopper is provided at the mouth of the sampling bottle 9, and a nitrogen purge port is provided to prevent the overflow of dangerous gases during the sampling stage to a certain extent, thereby improving the safety of the sampling process.

[0067] like Figure 2 and Figure 3 As shown, the present application provides a closed sampling method for carboxylated nitrile latex, the method comprising:

[0068] S1. The carboxyl nitrile latex in the polymerization reactor is sampled by the sampling device, and backflushed with nitrogen to obtain a sampling device containing a sample;

[0069] S2. Inserting a sampler into the sampling device and extracting a sample to be tested;

[0070] S3. Backflush the sampling device and then discharge the sampled exhaust gas to complete the sampling;

[0071] or,

[0072] S1. The sampling device is evacuated, and then the sampling device is used to sample the carboxyl nitrile latex in the degassing kettle to obtain a sampling device containing a sample;

[0073] S2. Insert a sampler into the sampling device and perform sample extraction to obtain a sampling sample to be tested;

[0074] S3. Blow back the sampling device, and then discharge the sampling waste gas to complete sampling.

[0075] This method is implemented based on the above sampling device. For the specific structure of the sampling device, reference can be made to the above embodiments. Since this method adopts some or all of the technical solutions of the above embodiments, it at least has all the beneficial effects brought by the technical solutions of the above embodiments, which will not be elaborated one by one here.

[0076] The following further elaborates the present application in combination with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. For the experimental methods without specific conditions noted in the following embodiments, they are usually determined according to industry standards. If there is no corresponding industry standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0077] Example 1

[0078] As Figure 1 shown, a closed sampling device for carboxybutadiene nitrile latex includes:

[0079] A sampling part, including a root cut-off valve 1, a sampling ball valve 6 and a sampling tube 4. The discharge port of the sampling ball valve 6 is communicated with a needle-type sampling bottle 9. The feed port of the root cut-off valve 1 is used to receive the carboxybutadiene nitrile latex flowing out from the sampling port of the polymerization kettle; the root cut-off valve 1 and the sampling ball valve 6 are communicated through the sampling tube 4;

[0080] A sampling part, including a sampling joint 7, a sampling buffer joint 12, a shield 8 and a sampling bottle 9 (including a bottle cap and a self-closing rubber stopper);

[0081] (1) Replace the self-closing rubber stopper of the sampling bottle 9 with a new one. Insert the sampling bottle 9 with the bottle cap and the self-closing rubber stopper into the sampling buffer joint 12 until the self-closing rubber stopper is punctured by the sampling needle on the sampling buffer joint 12, and then fasten the snap ring. The exhaust port 13 on the sampling joint 7 is connected to the waste gas pipeline.

[0082] (2) Open the root cut-off valve 1 and the sampling ball valve 6 in sequence. The sample starts to flow into the sampling bottle 9 through the sampling tube 4. The gas escaping from the liquid during sampling is discharged into the factory waste gas pipeline through the exhaust port 13 of the sampling joint 7. When the required sample volume is obtained, close the sampling ball valve 6.

[0083] (3) Open the snap ring, remove the sampling bottle 9, the self-closing rubber stopper automatically seals, tighten the bottle cap, and one sampling is completed.

[0084] Since a part of the initial carboxyl nitrile latex sample is the sample remaining in the equipment pipe orifice and sampling line, rather than the fresh sample in the polymerization kettle as required, it is necessary to take another new empty sampling bottle 9 and repeat the above steps (1), (2) and (3). The sample taken in this sampling bottle 9 is the required fresh sample.

[0085] Example 2

[0086] As Figure 2 and Figure 3 shown, taking the carboxyl nitrile latex project of a certain company as an example, the specific working process of the sampling device provided in Example 1 is as follows:

[0087] (1) First connect the empty sampling bottle 9 to the sampling buffer joint 12, and then connect the sampling buffer joint 12 to the sampling joint 7. Check whether the sampling ball valve 6 is in the closed state, and open the valve on the exhaust pipeline to open the exhaust port 13.

[0088] (2) Open the nitrogen pressure reducing valve 5, observe the pressure gauge reading, fill the sampling pipe 4 with a certain pressure, then close the nitrogen pressure reducing valve 5, open the root cut-off valve 1. When the pressure gauge reading drops significantly, open the nitrogen pressure reducing valve 5 again to make the pressure gauge reading stable within a certain pressure range. The purpose of this operation is to backflush the carboxyl nitrile latex in the equipment pipe orifice or sampling sub-line back to the equipment or process main pipeline, so that the materials in the equipment pipe orifice and sampling sub-line are fresh samples.

[0089] (3) After nitrogen backflushing for a certain time, close the nitrogen pressure reducing valve 5, and then slowly open the sampling ball valve 6 to observe the liquid level change of the latex emulsion flowing into the sampling bottle 9. When the latex emulsion reaches a certain height in the sampling bottle 9, close the sampling ball valve 6.

[0090] (4) Open the sampling port of the needle-type sampling valve 3, insert the sampling syringe into the needle insertion port of the rubber gasket 11 to extract the sample. When a certain volume of the sample is extracted, pull out the syringe, and then close the sampling port on the needle-type sampling valve 3.

[0091] (5) Open the nitrogen pressure reducing valve 5 again, observe that the pressure gauge reading is stable within a certain pressure range, and use nitrogen to backflush the remaining carboxyl nitrile latex in the sampling pipe 4 back to the equipment and sampling main pipeline. After backflushing for a certain time, close the root cut-off valve 1, open the cut-off sampling ball valve 6 to allow nitrogen to purge into the sampling bottle 9, displace the harmful gas in the sampling bottle 9 through the exhaust port 13, and then close the nitrogen pressure reducing valve 5 and the valve of the exhaust port 13, and remove the sampling bottle 9 to end the sampling.

[0092] (6) When sampling under vacuum conditions, before opening the exhaust pipeline valve to form the exhaust port 13 in step (1), connect the portable lithium battery vacuum pump 10 to the exhaust port 13 through a quick connector at the exhaust port 13, and then connect the outlet of the vacuum pump 10 to the exhaust port 13. After step (2) is completed, close the nitrogen pressure reducing valve 5, and then slowly open the sampling ball valve 6 to relieve the pressure of the gas in the pipeline into the sampling bottle 9. Then, turn on the portable vacuum pump 10 and observe the change in the latex emulsion level in the sampling bottle 9. When the latex emulsion reaches a certain height in the sampling bottle 9, close the sampling ball valve 6 and implement step (4). After step (4) is completed, implement step (5). In step (5), it should be noted that the vacuum pump 10 needs to be turned on to discharge the gas into the exhaust line, and when purging with nitrogen, attention should be paid to the pressure change in the sampling bottle 9 so that the pointer should be near the "0" position.

[0093] (7) To reduce the gelling of latex in the sampling device, an optional step is to open the hot water interface 2 and use hot water to flush the sampling line, and the flushing water flows into the sampling bottle 9 by gravity; this step can be operated once after multiple batches of sampling.

[0094] Comparative Example 1

[0095] Compare Comparative Example 1 with Example 2. The differences between Comparative Example 1 and Example 2 are as follows:

[0096] As Figure 4 shown, common 50 ml or 100 ml medical airtight plastic syringes on the market can be used as samplers.

[0097] Relevant experiments and effect data:

[0098] Actual sampling was carried out using the sampling devices of Example 2 and Comparative Example 1 respectively, and the accuracy and timeliness results are shown in Table 1.

[0099] Table 1 Accuracy and timeliness results of the sampling devices of each example and comparative example

[0100]

[0101] In the accuracy test process in Table 1, in Example 2, since sampling from the polymerization kettle needs to avoid blowing nitrogen back into the kettle as much as possible, if the sampling is improper, the sample taken may not be the instantaneous sample composition, which will cause some deviation from the true composition of the materials in the polymerization kettle.

[0102] At the same time, when sampling under vacuum conditions, due to the high viscosity and poor fluidity of carboxy nitrile latex, and due to the height difference, the sampling tube needs to be extended, and the sampling time will be prolonged.

[0103] As can be seen from the data in Table 1, the reason for the low accuracy of the samples taken in Comparative Example 1 is that when the sample flows into the sampling bottle, butadiene and acrylonitrile entrained in the emulsion will volatilize from the latex due to reduced pressure. In addition, the emulsifier contained in the latex will also foam in the bottle, making it difficult to take accurate samples. By chromatographic analysis of the sample, the composition of butadiene and acrylonitrile will be inaccurate, that is, it cannot accurately reflect the actual reaction conditions in the polymerization kettle.

[0104] A closed sampling device for carboxylated nitrile latex provided by an embodiment of the present application, through a sampling part including a root cut-off valve 1, a needle-type sampling valve 3 and a sampling tube 4, combined with a sampling part including a sampling joint 7, a sampling buffer joint 12 and a sampling bottle 9. During the syringe extraction stage, the emulsion is almost completely filled, no foam is generated, and no gas escapes from the sample. Therefore, it can ensure the freshness of the sample and the immediacy and accuracy of the detection data. At the same time, it can also solve the problem that it is difficult to sample carboxylated nitrile latex with high viscosity under vacuum conditions.

[0105] At the same time, this sampling device only uses a syringe for sampling, so the material loss during the sampling process is small. Since the equipment for syringe sampling has a low cost, is easy to manufacture and purchase, it can effectively reduce the production cost of the device detection system.

[0106] And this sampling device solves the problem that the sample detection data is inaccurate due to a large amount of foam entrained in the latex emulsion sample and the easy volatilization of volatile materials from the latex during the sampling of the reaction materials in the polymerization kettle. And this sampling device also solves the problem of difficult sampling of the carboxylated nitrile latex degassing kettle under vacuum conditions.

[0107] Furthermore, the entire sampling process of this sampling device is closed, avoiding the spillage of highly toxic gases such as butadiene and acrylonitrile into the environment, thus avoiding health damage to operators during sampling.

[0108] Furthermore, due to the setting of the on-line cleaning and purging steps in this sampling device, the risk of blockage of carboxylated nitrile latex in the sampling pipeline is reduced, thereby reducing the loss of sampling devices, and also reducing the labor intensity of operators. Therefore, it can comprehensively improve the occupational health and environmental protection level of factory production.

[0109] The various embodiments of the present application may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the present application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within that range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0110] In the present application, unless otherwise stated, the orientation terms such as "upper" and "lower" specifically refer to the drawing directions in the figures. Additionally, in the description of the specification of the present application, the terms "comprising", "including", etc. mean "including but not limited to". In this document, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. Where A and B can be singular or plural. In this document, "at least one" means one or more, and "a plurality" means two or more. "At least one kind", "at least one of the following items (pieces)" or similar expressions refer to any combination of these items, including any combination of single items (pieces) or plural items (pieces). For example, "at least one of a, b, or c", or, "at least one of a, b, and c" can both represent: a, b, c, a - b (i.e., a and b), a - c, b - c, or a - b - c, where a, b, and c can be single or multiple respectively.

[0111] The above description is only the specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather will conform to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A closed sampling device for carboxylated nitrile latex, characterized in that, the sampling device comprises: A sampling part, the sampling part includes a root cut-off valve (1), a needle-type sampling valve (3) and a sampling tube (4). The discharge port of the root cut-off valve (1) is communicated with the feed port of the needle-type sampling valve (3), and the feed port of the root cut-off valve (1) is used to collect carboxylated nitrile latex; the discharge port of the needle-type sampling valve (3) is communicated with the feed port of the sampling tube (4); A sampling part, the sampling part includes a sampling joint (7), a sampling buffer joint (12) and a sampling bottle. The feed port of the sampling joint (7) is communicated with the discharge port of the sampling tube (4), the discharge port of the sampling joint (7) is communicated with the feed port of the sampling buffer joint (12), and the discharge port of the sampling buffer joint (12) is communicated with the sampling bottle; A vacuum pump (10), the vacuum pump (10) is arranged in communication with the sampling buffer joint (12).

2. The sampling device according to claim 1, characterized in that, the needle-type sampling valve (3) includes a rubber gasket (11); a needle insertion port is provided on the rubber gasket (11) to achieve instant and accurate sampling of the needle-type sampling valve (3).

3. The sampling device according to claim 1, characterized in that, the sampling part further includes a sampling ball valve (6). The feed port of the sampling ball valve (6) is communicated with the discharge port of the sampling tube (4), and the discharge port of the sampling ball valve (6) is communicated with the feed port of the sampling joint (7).

4. The sampling device according to claim 1, characterized in that, the sampling part further includes a shield (8). The two ends of the shield (8) are respectively rotatably connected to the sampling buffer joint (12), and the bottom of the shield (8) abuts against the bottom of the sampling bottle.

5. The sampling device according to claim 1, characterized in that, the sampling device further includes: A nitrogen pressure reducing valve (5), the nitrogen pressure reducing valve (5) is arranged at the discharge port of the sampling tube (4), and the inlet of the nitrogen pressure reducing valve (5) is communicated with a nitrogen generating device to form a nitrogen purge port.

6. The sampling device according to claim 5, characterized in that, the sampling part further includes a hot water interface (2), and the hot water interface (2) is arranged between the root cut-off valve (1) and the needle-type sampling valve (3).

7. The sampling device according to claim 1, characterized in that, the sampling part further includes an exhaust port (13), and the exhaust port (13) is arranged on one side of the sampling joint (7) to discharge sampling waste gas.

8. The sampling device according to claim 7, characterized in that, the vacuum pump (10) is communicated with the sampling joint (7) through the exhaust port (13).

9. The sampling device according to claim 1, characterized in that, the bottle mouth of the sampling bottle is provided with a self-closing rubber stopper.

10. A closed sampling method for carboxylated nitrile latex, characterized in that, the method includes: Sample the carboxy-terminated acrylonitrile-butadiene latex in the polymerization kettle using the sampling device described in any one of claims 1-9, and backflush with nitrogen to obtain a sampling device containing the sample; Insert a sampler into the sampling device and extract the sample to obtain a sampling sample to be tested; Backflush the sampling device, and then discharge the sampling waste gas to complete the sampling; Or, Vacuum the sampling device described in any one of claims 1-9, and then use the sampling device to sample the carboxy-terminated acrylonitrile-butadiene latex in the degassing kettle to obtain a sampling device containing the sample; Insert a sampler into the sampling device and extract the sample to obtain a sampling sample to be tested; Backflush the sampling device, and then discharge the sampling waste gas to complete the sampling.

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