A closed-loop sampling system for a vinyl chloride converter
By designing a closed-loop sampling system for the vinyl chloride converter, the problems of environmental pollution and high analysis frequency during the sampling process of the vinyl chloride converter were solved, realizing automated, rapid and accurate sampling and analysis, and ensuring the optimized operation of the converter.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 云南天冶化工有限公司
- Filing Date
- 2025-07-16
- Publication Date
- 2026-07-03
AI Technical Summary
The sampling process of existing vinyl chloride converters poses environmental pollution problems, and the high frequency of analysis leads to insufficient data accuracy and timeliness.
Design a closed-loop sampling system for vinyl chloride converters, including a sampling ball valve, an analysis unit, and connecting pipelines, to achieve automatic sampling and analysis. Use nitrogen and standard gas pipelines for system calibration and residual gas removal to ensure measurement accuracy. Use a multi-sampling valve and flow path switching device to achieve sequential analysis of multiple converters.
It enables automated and rapid sampling and analysis, improves the accuracy and timeliness of data, reduces environmental pollution, and ensures the optimized operation of the converter.
Smart Images
Figure CN224456693U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of vinyl chloride sampling technology, and more specifically, to a closed-loop sampling system for a vinyl chloride converter. Background Technology
[0002] In polyvinyl chloride (PVC) production, the quality of vinyl chloride monomer is crucial for ensuring the polymerization and product quality. Therefore, it is necessary to take timely and accurate samples to determine the content of trace impurities such as acetylene, dichloroethane, water, and iron in the vinyl chloride monomer, and to adjust the distillation process control parameters and polymerization formulation promptly based on the measurement data.
[0003] Currently, vinyl chloride converters often use manual sampling. A rubber tube is used as a sampling connection pipe at the sampling port of the outlet pipe. During sampling, the sampling valve is opened to directly discharge the media inside the rubber tube into the atmosphere for replacement. Then, a bulb is used to connect the rubber tube for sampling. The sampling frequency is 12 hours / time for primary conversion and 2 hours / time for secondary conversion. There are 20 primary converters and 18 secondary converters. The sampling and analysis frequency is relatively high. The gas discharged from the replacement contains acetylene, hydrogen chloride, and vinyl chloride, causing environmental pollution. Utility Model Content
[0004] The purpose of this invention is to provide a closed-loop sampling system for vinyl chloride converters, which can automatically sample and analyze, reduce the time of material analysis in the analysis process, improve the accuracy and timeliness of analysis data, and achieve precise control of the reaction of a single converter.
[0005] This utility model is achieved through the following technical solution:
[0006] A closed-loop sampling system for a vinyl chloride converter includes a converter with a sampling ball valve at the converter outlet; an analysis unit including an injection valve, an online analytical chromatograph, and an outlet valve; and connecting pipelines including an injection pipeline, an air pipeline, a nitrogen pipeline, a standard gas pipeline, and an outlet pipeline. The two ends of the injection pipeline are connected to the outlet of the sampling ball valve and the inlet of the injection valve, respectively. The air pipeline, nitrogen pipeline, and standard gas pipeline are connected to the injection pipeline, and the outlet pipeline is connected to the outlet of the outlet valve.
[0007] Furthermore, the sampling ball valve is connected to a multi-sampling valve via a sampling pipeline, and the outlet of the multi-sampling valve is connected to the inlet pipeline via a flow path switching device.
[0008] Furthermore, a filter screen plate is detachably installed at the outlet end of the sampling pipeline, and the filter screen plate has a pore size of 50μm.
[0009] Furthermore, the injection line is sequentially equipped with a two-way ball valve, a filter, a diaphragm pump, a filter, a needle valve, a three-way ball valve, a needle valve, and a flow meter, and the diaphragm pump is connected in parallel with a needle valve.
[0010] Furthermore, the second filter is connected to a displacement outlet pipeline, and a two-way ball valve is installed on the displacement outlet pipeline.
[0011] Furthermore, the nitrogen pipeline is sequentially equipped with a filter pressure reducing valve one and a needle valve four. The outlet of the filter pressure reducing valve one is also connected to a one-way pipeline. The other end of the one-way pipeline is connected to the outlet of the diaphragm pump. The one-way pipeline is equipped with a two-way ball valve three and a one-way valve.
[0012] Furthermore, the air pipeline is equipped with a filter pressure reducing valve 2, and the filter pressure reducing valve 1 is connected to needle valve 5 and needle valve 6.
[0013] Furthermore, the online analytical chromatograph includes a transmitting unit, a receiving unit, and a positive pressure control module.
[0014] The technical solution of this utility model has at least the following advantages and beneficial effects:
[0015] In this invention, the sampling ball valve, analysis unit, and connecting pipelines enable closed-loop sampling, shortening analysis time and allowing operators to adjust the converter load promptly based on online automatic closed-loop analysis results, ensuring optimal converter operation. The standard gas pipeline can supply vinyl chloride standard gas of known concentration to calibrate the instrument's measurement range (span calibration), adjust the calibration curve, and ensure detection accuracy across the entire range. The nitrogen pipeline utilizes the inert properties of nitrogen to remove residual vinyl chloride or other gases from the system, preventing cross-contamination and ensuring the accuracy of subsequent measurements. In situations requiring a dry or inert environment, high-purity nitrogen can serve as a more stable zero-point calibration gas, avoiding interference from moisture or impurities in the air. The air pipeline can supply purified air (free of vinyl chloride and interfering substances) to adjust the instrument's zero-point reference, ensuring accurate baseline readings in the absence of target gas, while also maintaining positive system pressure to ensure normal sampling and analysis. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the closed-loop sampling system for a vinyl chloride converter provided in Embodiment 1 of this utility model;
[0018] Figure 2 Another schematic diagram of the converter sampling provided in Embodiment 1 of this utility model;
[0019] Figure 3 This is a schematic diagram of the structure of the filter screen plate provided in Embodiment 1 of this utility model.
[0020] Icons: 1-Converter, 2-Sampling ball valve, 3-Injection valve, 4-Outlet valve, 5-Online analytical chromatograph, 6-Injection line, 7-Air line, 8-Nitrogen line, 9-Standard gas line, 10-Emission line, 11-Two-way ball valve one, 12-Filter one, 13-Diaphragm pump, 14-Filter two, 15-Needle valve one, 16-Three-way ball valve one, 17-Needle valve two, 18-Flow meter, 19-Needle valve three 20-Replacement outlet pipeline, 21-Two-way ball valve II, 22-Filter pressure reducing valve I, 23-Needle valve IV, 24-One-way pipeline, 25-Two-way ball valve III, 26-One-way valve, 27-Filter pressure reducing valve II, 28-Needle valve V, 29-Needle valve VI, 30-Flow path switching device, 31-Sampling pipeline, 32-Multi-way sampling valve, 33-Filter sieve plate, 51-Transmitting unit, 52-Receiving unit, 53-Positive pressure control module. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.
[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.
[0024] In the description of this utility model, it should be noted that if terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" appear to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.
[0025] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0026] Example 1
[0027] like Figures 1-3 As shown, this embodiment provides a closed-loop sampling system for a vinyl chloride converter, including a converter 1, with a sampling ball valve 2 at the outlet of the converter 1; an analysis unit, including an injection valve 3, an online analytical chromatograph 5, and an outlet valve 4; and connecting pipelines, including an injection pipeline 6, an air pipeline 7, a nitrogen pipeline 8, a standard gas pipeline 9, and an outlet pipeline 10. The two ends of the injection pipeline 6 are respectively connected to the outlet of the sampling ball valve 2 and the inlet of the injection valve 3. The air pipeline 7, the nitrogen pipeline 8, and the standard gas pipeline 9 are respectively connected to the injection pipeline 6. The outlet pipeline 10 is connected to the outlet of the outlet valve 4.
[0028] The sampling ball valve 2, analysis unit, and connecting pipelines enable closed-loop sampling, shortening analysis time and allowing operators to adjust the converter load promptly based on online automatic closed-loop analysis results, ensuring converter 1 operates at its optimal state. The standard gas line 9 can supply vinyl chloride standard gas of known concentration to calibrate the instrument's measurement range (span calibration), adjust the calibration curve, and ensure detection accuracy across the entire range. The nitrogen line 8 utilizes the inert properties of nitrogen to remove residual vinyl chloride or other gases from the instrument, preventing cross-contamination and ensuring the accuracy of subsequent measurements. In situations requiring a dry or inert environment, high-purity nitrogen can serve as a more stable zero-point calibration gas, avoiding interference from moisture or impurities in the air. The air line 7 can supply purified air (free of vinyl chloride and interfering substances) to adjust the instrument's zero-point reference, ensuring accurate baseline readings in the absence of target gas, while also maintaining positive system pressure to ensure normal sampling and analysis.
[0029] Since the gases emitted during the production process mainly include vinyl chloride and acetylene, two analysis units can be connected in parallel in the sampling system. One analysis unit can sample and analyze vinyl chloride, and the other analysis unit can sample and analyze acetylene, enabling multi-gas sampling and analysis. The gas emitted from the emission pipeline 10 can be returned to the converter 1.
[0030] In a preferred embodiment, the sampling ball valve 2 is connected to a multi-sampling valve 32 via a sampling line 31. The outlet of the multi-sampling valve 32 is connected to the inlet line 6 via a flow path switching device 30. The multi-sampling valve 32 can be selected as a 6, 8, 12, 16, or 20-position valve, connecting 6-20 converters 1. Further capacity can be achieved by adding more multi-position valves. The flow path switching device 30 enables sequential analysis of the outlet gases from up to 20 converters 1. The analysis cycle for a single converter 1 outlet gas is approximately 5 minutes. The flow path switching device 30 can define whether or not to switch converters 1 as needed.
[0031] In a preferred embodiment, a filter screen 33 is detachably installed at the outlet end of the sampling pipeline 31. The filter screen 33 has a pore size of 50 μm. The filter screen 33 is snapped onto the outlet end of the sampling pipeline 31. The filter screen 33 can filter dust in the gas, reducing interference with vinyl chloride sampling and analysis. Furthermore, the filter screen 33 is easy to replace, maintain, and clean.
[0032] In a preferred embodiment, the sample inlet line 6 is sequentially provided with a two-way ball valve 11, a filter 12, a diaphragm pump 13, a filter 2 14, a needle valve 15, a three-way ball valve 16, a needle valve 2 17, and a flow meter 18, and the diaphragm pump 13 is connected in parallel with a needle valve 3 19.
[0033] In a preferred embodiment, the inlet end of the filter 14 is connected to a displacement outlet pipeline 20, and a two-way ball valve 21 is provided on the displacement outlet pipeline 20. Nitrogen gas is introduced through the nitrogen pipeline 8 to replace residual vinyl chloride or other gases inside the instrument, and then discharged through the displacement outlet pipeline 20 for easy reference during the next measurement.
[0034] In a preferred embodiment, the nitrogen line 8 is sequentially equipped with a filter pressure reducing valve 22 and a needle valve 23. The outlet of the filter pressure reducing valve 22 is also connected to a one-way line 24, the other end of which is connected to the outlet of the diaphragm pump 13. The one-way line 24 is equipped with a two-way ball valve 25 and a one-way valve 26. The one-way line 24 can guide nitrogen to the connecting line between the sample injection line 6 and the flow path switching device 30, which can replace residual gas in this part of the instrument and further improve the accuracy of the next vinyl chloride measurement. At the same time, the one-way valve 26 can prevent gas on the sample injection line 6 from entering the nitrogen line 8.
[0035] In a preferred embodiment, the air line 7 is provided with a filter pressure reducing valve 27, which is connected to a needle valve 5 28 and a needle valve 6 29.
[0036] In a preferred embodiment, the online analytical chromatograph 5 includes a transmitting unit 51, a receiving unit 52, and a positive pressure control module 53. The online analytical chromatograph 5 is an LGA-4700 laser analyzer (Juguang Technology). The transmitting unit 51 consists of a human-machine interface, a laser driver module, a central processing module, a semiconductor laser, and precision optical components, primarily realizing semiconductor laser emission, spectral data processing, and human-machine interaction. The receiving unit 52 consists of a photoelectric sensor, a signal processing module, a power supply module, and precision optical components, primarily receiving sensor signals and transmitting spectral absorption signals to the transmitting unit 51 for processing. Furthermore, the transmitting unit 51 and the receiving unit 52 adopt a positive pressure explosion-proof design. The positive pressure control module 53 adopts an explosion-proof design and integrates a pressure sensor, signal processing, power control, and information display modules.
[0037] The working principle of a closed-loop sampling system for a vinyl chloride converter is as follows: Standard gas is introduced into the analysis unit via standard gas line 9 to debug and calibrate the online analytical chromatograph 5. Purified air (free of vinyl chloride and interfering substances) is introduced into the system via air line 7 to calibrate the online analytical chromatograph 5 and maintain positive pressure in the system. The sample gas from the converter 1 is pretreated through sampling ball valve 2, sampling line 31, multi-way sampling valve 32, and flow path switching device 30. The pretreated sample gas is then analyzed by the online analytical chromatograph 5 via injection line 6 and injection valve 3. The converter 1 is adjusted based on the analysis results. The analyzed gas is then returned to the converter 1 via exhaust line 10. Finally, nitrogen is introduced into the system via nitrogen line 8 to remove residual vinyl chloride or other gases from the system.
[0038] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A closed loop sampling system for a vinyl chloride converter characterized by, The system includes a converter with a sampling ball valve at its outlet; an analysis unit including an injection valve, an online analytical chromatograph, and an outlet valve; and connecting pipelines including an injection pipeline, an air pipeline, a nitrogen pipeline, a standard gas pipeline, and an outlet pipeline. The two ends of the injection pipeline are connected to the outlet of the sampling ball valve and the inlet of the injection valve, respectively. The air pipeline, nitrogen pipeline, and standard gas pipeline are connected to the injection pipeline, and the outlet pipeline is connected to the outlet of the outlet valve.
2. The vinyl chloride converter closed loop sampling system of claim 1, wherein, The sampling ball valve is connected to a multi-sampling valve via a sampling pipeline, and the outlet of the multi-sampling valve is connected to the inlet pipeline via a flow path switching device.
3. The vinyl chloride converter closed loop sampling system of claim 2, wherein, The outlet end of the sampling pipeline is detachably equipped with a filter screen plate, the filter screen plate having a pore size of 50μm.
4. The vinyl chloride converter closed loop sampling system of claim 1, wherein, The injection line is sequentially equipped with a two-way ball valve, a filter, a diaphragm pump, a filter, a needle valve, a three-way ball valve, a needle valve, and a flow meter. The diaphragm pump is connected in parallel with a needle valve.
5. The vinyl chloride converter closed loop sampling system of claim 4, wherein, The filter 2 is connected to a displacement outlet pipeline, and a two-way ball valve 2 is installed on the displacement outlet pipeline.
6. The vinyl chloride converter closed cycle sampling system of claim 4, wherein, The nitrogen pipeline is equipped with a filter pressure reducing valve one and a needle valve four in sequence. The outlet of the filter pressure reducing valve one is also connected to a one-way pipeline. The other end of the one-way pipeline is connected to the outlet of the diaphragm pump. The one-way pipeline is equipped with a two-way ball valve three and a one-way valve.
7. The vinyl chloride converter closed loop sampling system of claim 1, wherein, The air pipeline is equipped with a filter pressure reducing valve 2, and the filter pressure reducing valve 1 is connected to needle valve 5 and needle valve 6.
8. The vinyl chloride converter closed loop sampling system of claim 1, wherein, The online analytical chromatograph includes a transmitting unit, a receiving unit, and a positive pressure control module.