An online sampling and sampling system for liquefied gas

Abstract

The utility model belongs to a kind of liquefied gas on-line sampling and sampling system;Including sampling part, sampling part is connected with analyser by pressure flow regulating unit and pressure reducing vaporization unit, and the outlet of analyser is connected with waste gas treater;The pressure reducing vaporization unit includes pressure reducing heater and the heat tracing inverted U-shaped tube that is set in series with pressure reducing heater, and pressure reducing heater and heat tracing inverted U-shaped tube are connected with vacuumizing part respectively, and pressure reducing heater is connected with gas replacement part, and heat tracing inverted U-shaped tube is connected with venting part;With the characteristics of reasonable process design, guaranteeing detection result accurate, multiple sampling sources can be analyzed and sampled by a set of equipment and avoiding damage of analysis instrument.

Description

Technical Field

[0001] This utility model belongs to the field of gas analysis technology, specifically a liquefied gas online sampling and injection system. Background Technology

[0002] As the chemical industry places increasingly stringent demands on analytical testing, especially for high-end electronic specialty gases, the analytical testing methods used in the production and product analysis processes are crucial, directly impacting product quality stability. In China, the analysis and sampling of liquefied gases commonly employs electric heating, requiring extensive heating tape to be wrapped around the analytical pipeline and instrument injection lines, controlled by a temperature control system. However, this method suffers from the following problems: 1. The sampling process is susceptible to interference and lacks representativeness. For example, sudden increases or decreases in the pressure of the sampling source, or changes in flow rate, can affect online sampling and consequently the analytical results. 2. The pressure and temperature during the vaporization process of liquefied gases are unstable, and incomplete vaporization can damage analytical instruments. 3. Continuous sampling and injection pose a risk of cross-contamination, increasing analysis time and affecting the results. Utility Model Content

[0003] To overcome the above deficiencies, this utility model provides an online sampling and injection system for liquefied gas, thereby solving the technical problems existing in the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is:

[0005] A liquefied gas online sampling and injection system includes a sampling unit, which is connected to an analyzer via a pressure and flow regulation unit and a pressure reduction and vaporization unit. The outlet of the analyzer is connected to a waste gas processor. The pressure reduction and vaporization unit includes a pressure reduction heater and a heat tracing inverted U-shaped tube connected in series with the pressure reduction heater. The pressure reduction heater and the heat tracing inverted U-shaped tube are respectively connected to a vacuum pump, the pressure reduction heater is connected to a gas replacement unit, and the heat tracing inverted U-shaped tube is connected to a venting unit.

[0006] The beneficial effects of this invention are as follows: The liquid phase product in the sampling unit has its pressure and flow rate adjusted by a pressure and flow rate regulating unit, thus avoiding sudden pressure increases or decreases and large flow rate variations. Furthermore, the liquid phase is depressurized and vaporized by a depressurization and vaporization unit to meet the analytical requirements of the analyzer. Specifically, the liquid phase is depressurized and vaporized using a depressurization heater, and further vaporized using a heated inverted U-shaped tube, preventing the liquid phase from entering the analyzer and affecting its service life. This invention prevents gas source contamination by equipping the depressurization heater with gas replacement and vacuum components, and the heated inverted U-shaped tube with venting and vacuum components, ensuring the accuracy of the test results. Simultaneously, the sampling unit described in this invention can be a gas cylinder, liquid phase product storage tank, liquid phase product production system, or liquid phase delivery pipeline, etc., for liquid phase storage. The sampling unit can include multiple liquid phase storage devices; that is, this invention can use a single online sampling and injection system to analyze the liquid phase in multiple liquid phase storage devices, thereby reducing equipment investment costs and improving equipment utilization.

[0007] Preferably, the pressure and flow rate regulating unit includes a pressure flow meter and an injection regulating valve disposed between the sampling section and the pressure reducing vaporization unit.

[0008] Preferably, the vacuuming component includes a first tee disposed between the pressure reducing heater and the heat tracing inverted U-shaped tube, a second tee disposed between the heat tracing inverted U-shaped tube and the analyzer, the third end of the first tee and the third end of the second tee being respectively connected to the third tee, the third end of the third tee being connected to the exhaust gas processor through a vacuum pump, a first pneumatic valve being provided between the third end of the first tee and the third tee, and a second pneumatic valve being provided between the third end of the third tee and the vacuum pump.

[0009] Preferably, the gas replacement component includes a fourth three-way valve disposed between the first three-way valve and the heat-tracing inverted U-shaped pipe, the third end of the fourth three-way valve being provided with a nitrogen replacement pipe with a third pneumatic valve; and a fifth three-way valve disposed between the sample injection regulating valve and the pressure reducing heater, the third end of the fifth three-way valve being connected to the waste gas processor through the replacement valve.

[0010] Preferably, the venting device includes a three-way valve disposed between the heat tracing U-shaped pipe and the second three-way valve, and the third end of the three-way valve is connected to the exhaust gas processor through a first flow meter and a fourth pneumatic valve.

[0011] Preferably, a two-stage pressure reducing valve is provided between the fourth tee and the heat tracing U-shaped pipe.

[0012] Preferably, a second flow meter and a fifth pneumatic valve are sequentially provided between the second three-way valve and the analyzer.

[0013] This utility model also includes a PLC control system. The signal input terminal of the PLC control system is connected to the pressure flow meter, the first flow meter, the second flow meter, the pressure sensor, and the differential pressure sensor. The signal output terminal of the PLC control system is connected to the injection regulating valve, the fifth pneumatic valve, the fourth pneumatic valve, the second pneumatic valve, and the secondary pressure reducing valve. The pressure sensor is installed on the pressure reducing heater, and the differential pressure sensor is installed on the secondary pressure reducing valve.

[0014] A liquefied gas online sampling and injection system was fabricated according to the above scheme. By incorporating a pressure flow meter, fluctuations in the sampling source pressure and flow rate can be monitored in real time. Adjustment of the injection regulating valve ensures a stable and continuous sampling process, making the sampling more representative. Furthermore, a two-stage pressure reduction and heating system is implemented: the pressure reducing heater and secondary pressure reducing valve provide two-stage pressure reduction, while the pressure reducing heater and heated inverted U-shaped tube provide two-stage heating. This ensures complete vaporization of the liquefied gas while maintaining a constant sample pressure, guaranteeing the accuracy of subsequent detection results. By incorporating gas replacement and vacuum components into the pressure reducing heater and venting and vacuum components into the heated inverted U-shaped tube, [the system] can avoid [problems]. Cross-contamination caused by changes in sample composition or sampling source can affect analytical results. Furthermore, the aforementioned setup enables a single system to analyze multiple sampling sources, reducing investment in analytical equipment and increasing equipment utilization while ensuring accurate results. This invention preferably employs automated sampling and injection processes, eliminating the need for human intervention and improving safety by avoiding human error. It is particularly suitable for the analysis of high-purity liquefied gases. It features a rational process design, ensures accurate results, allows for the analysis of multiple sampling sources with a single system, and avoids damage to analytical instruments. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] Figure 2 This is a schematic diagram of the control principle of this utility model.

[0018] In the diagram: 1. Sampling unit; 2. Pressure reducing heater; 3. Heated U-shaped tube; 4. Analyzer; 5. Waste gas processor; 6. Vacuum pump; 7. Secondary pressure reducing valve; 8. PLC control system; 9. First three-way valve; 10. Second three-way valve; 11. Third three-way valve; 12. Fourth three-way valve; 13. Fifth three-way valve; 14. Three-way valve; 15. Nitrogen replacement pipeline; 16. Replacement valve; 17. Pressure flow meter; 18. Sample injection regulating valve; 19. First pneumatic valve; 20. Second pneumatic valve; 21. Third pneumatic valve; 22. Fourth pneumatic valve; 23. Fifth pneumatic valve; 24. First flow meter; 25. Second flow meter; 26. Pressure sensor; 27. Differential pressure sensor. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0020] The following is in conjunction with the appendix Figure 1 This application provides a further detailed description of an online sampling and injection system for liquefied gas, comprising a sampling unit 1. The sampling unit 1 is connected to an analyzer 4 via a pressure and flow regulating unit and a pressure-reducing vaporization unit. The outlet of the analyzer 4 is connected to a waste gas processor 5. The pressure-reducing vaporization unit includes a pressure-reducing heater 2 and a heat-tracing inverted U-shaped tube 3 connected in series with the pressure-reducing heater 2. The pressure-reducing heater 2 and the heat-tracing inverted U-shaped tube 3 are respectively connected to a vacuum pump, the pressure-reducing heater 2 is connected to a gas replacement unit, and the heat-tracing inverted U-shaped tube 3 is connected to a venting unit. The sampling unit 1 described in this invention can be a liquid phase storage device such as a gas cylinder, a liquid phase product storage tank, or a liquid phase product production system. The sampling unit 1 can contain multiple liquid phase storage devices, meaning this invention can sample and analyze multiple sampling sources. The liquid phase sample in the sampling unit 1 is adjusted in pressure and flow rate via a pressure-flow regulating unit, thus avoiding sudden pressure increases or decreases and large flow rate changes. Furthermore, the liquid phase is depressurized and vaporized by a depressurization and vaporization unit to meet the analytical requirements of the analyzer. Specifically, the liquid phase is depressurized and vaporized via a depressurization heater 2, and further vaporized using a heated inverted U-shaped tube 3, preventing the liquid phase from entering the analyzer 4 and affecting its service life. By equipping the depressurization heater 2 with gas replacement and vacuum components, and the heated inverted U-shaped tube 3 with venting and vacuum components, this invention prevents gas source contamination, thereby ensuring the accuracy of the detection results.

[0021] Furthermore, the pressure and flow rate regulating unit includes a pressure flow meter 17 and an injection regulating valve 18 disposed between the sampling unit 1 and the pressure-reducing vaporization unit. This invention uses the pressure flow meter 17 to monitor fluctuations in the sampling source pressure and flow rate in real time, and adjusts the injection regulating valve 18 to ensure a stable and continuous sampling process, making the sampling more representative and laying the foundation for accurate subsequent analysis results.

[0022] Furthermore, the vacuuming component includes a first tee 9 disposed between the pressure-reducing heater 2 and the heat-tracing inverted U-shaped tube 3, a second tee 10 disposed between the heat-tracing inverted U-shaped tube 3 and the analyzer 4, the third ends of the first tee 9 and the second tee 10 being respectively connected to a third tee 11, the third end of the third tee 11 being connected to the exhaust gas processor 5 via a vacuum pump 6, a first pneumatic valve 19 being disposed between the third end of the first tee 9 and the third tee 11, and a second pneumatic valve 20 being disposed between the third end of the third tee 11 and the vacuum pump 6. This invention can perform vacuuming treatment on the pressure-reducing heater 2, the heat-tracing inverted U-shaped tube 3, and related pipelines via the vacuum pump 6, and the first pneumatic valve 19 can prevent sample gas short circuits during normal sampling.

[0023] Furthermore, the gas replacement component includes a fourth three-way valve 12 disposed between the first three-way valve 9 and the heat-tracing inverted U-shaped pipe 3, with a nitrogen replacement pipeline 15 equipped with a third pneumatic valve 21 at the third end of the fourth three-way valve 12; and a fifth three-way valve 13 disposed between the sample injection regulating valve 18 and the pressure reducing heater 2, with the third end of the fifth three-way valve 13 connected to the waste gas processor 5 via a replacement valve 16. The gas replacement component described in this invention is mainly used to replace the gas in the pressure reducing heater 2 and related pipelines before and after sampling, to prevent cross-contamination during continuous sampling and injection, and to ensure the accuracy of the test results.

[0024] Furthermore, the venting device includes a three-way valve 14 disposed between the heat-tracing inverted U-shaped pipe 3 and the second three-way valve 10. The third end of the three-way valve 14 is connected to the exhaust gas processor 5 via a first flow meter 24 and a fourth pneumatic valve 22. The venting device described in this invention mainly vents the heat-tracing inverted U-shaped pipe 3 and related pipelines before and after sampling.

[0025] Furthermore, a secondary pressure reducing valve 7 is provided between the fourth tee 12 and the heat tracing U-shaped pipe 3.

[0026] Furthermore, a second flow meter 25 and a fifth pneumatic valve 23 are sequentially provided between the second three-way valve 10 and the analyzer 4.

[0027] Further, see Figure 1 and Figure 2The present invention also includes a PLC control system 8. The signal input terminal of the PLC control system 8 is connected to the pressure flow meter 17, the first flow meter 24, the second flow meter 25, the pressure sensor 26 and the differential pressure sensor 27. The signal output terminal of the PLC control system 8 is connected to the injection regulating valve 18, the fifth pneumatic valve 23, the fourth pneumatic valve 22, the second pneumatic valve 20 and the secondary pressure reducing valve 7. The pressure sensor 26 is installed on the pressure reducing heater 2, and the differential pressure sensor 27 is installed on the secondary pressure reducing valve 7.

[0028] The working principle of this utility model is as follows: Before and after use, the pressure reducing heater 2 and its auxiliary pipelines need to undergo gas replacement and vacuuming, and the heat tracing U-shaped tube 3 and its auxiliary pipelines need to undergo venting and vacuuming. The specific process is as follows: When performing gas replacement and vacuuming on the pressure reducing heater 2 and its auxiliary pipelines, firstly, close the injection regulating valve 18 and the secondary pressure reducing valve 7, open the replacement valve 16 and the third pneumatic valve 21, and nitrogen gas sequentially passes through the third pneumatic valve 21, the pressure reducing heater 2, and the replacement valve 16 into the waste gas processor 5 for replacement and venting. When the pressure displayed on the pressure sensor 26 is 0, the replacement and venting are completed. Close the replacement valve 16 and the third pneumatic valve 21, open the first pneumatic valve 19 and the second pneumatic valve 20, and start the vacuum pump 6. Vacuuming is performed on the pressure reducing heater 2 and its auxiliary pipelines, and the vacuumed gas enters the exhaust gas processor 5. When the pressure displayed on the pressure sensor 26 is -85 kPa, the vacuum pump 6, the first pneumatic valve 19, and the second pneumatic valve 20 are shut off. At this time, the replacement and vacuuming process of the pressure reducing heater 2 and its auxiliary pipelines is completed. When venting and vacuuming the heat tracing U-shaped pipe 3 and its auxiliary pipelines, the fourth pneumatic valve 22 is opened, and the first flow meter 24 is set to 0.3 L / min for venting. After the discharge flow rate is reached, the fourth pneumatic valve 22 is closed. Then, the second pneumatic valve 20 is opened, and the vacuum pump 6 is started for vacuuming. The vacuuming process lasts for 30 seconds, and then the second pneumatic valve 20 is closed. The above venting and vacuuming processes can be repeated as needed. It is important to note that the above processing is required before and after each sampling and injection. When sampling is required, the sampling source in sampling unit 1, when passing through pressure and flow meter 17, monitors the changes in pressure and flow rate of the sampling source in real time. Simultaneously, the injection regulating valve 18 adjusts the pressure and flow rate to ensure stable pressure and flow rate (specifically, maintaining a stable pressure of ±0.01 MPa and a stable flow rate of 0.5 L / min to reduce interference caused by fluctuations in sampling source pressure) before entering the pressure-reducing heater 2. The pressure-reducing heater 2 is equipped with temperature and pressure sensors, and automatically adjusts to the liquid sample after the temperature and pressure are set. The sample gas is depressurized and vaporized by heating. The vaporized sample gas enters the secondary pressure reducing valve 7 and is detected by the differential pressure sensor 27. The pressure after the valve of the secondary pressure reducing valve 7 is set to meet the injection standard (the opening of the secondary pressure reducing valve 7 can be adjusted according to the data of the differential pressure sensor 27 to stabilize the pressure after the valve of the secondary pressure reducing valve 7). When injection is required, the fifth pneumatic valve 23 is opened and the injection flow rate of the second flow meter 25 is set (the flow rate of the second flow meter 25 can be set to 0.3 L / min). After the injection is completed, the fifth pneumatic valve 23 is closed. Then, the heated inverted U-shaped tube 3 and its auxiliary pipelines can be vented and evacuated.This invention enables the analysis and detection of multiple sampling sources using the same injection and sampling system while ensuring accurate test results, thereby improving equipment utilization. Simultaneously, the dual-stage depressurization and dual-stage heating system ensures complete vaporization of the liquefied gas while maintaining constant sample pressure, laying the foundation for accurate subsequent test results. Furthermore, this invention automates the sampling and injection process, eliminating the need for manual operation and relying on automatic program control. This improves safety and avoids the impact of human intervention, making it particularly suitable for the analysis of high-purity liquefied gases.

[0029] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. A liquefied gas online sampling and injection system, comprising a sampling unit (1), characterized in that: The sampling unit (1) is connected to the analyzer (4) through the pressure and flow regulation unit and the pressure reduction and vaporization unit, and the outlet of the analyzer (4) is connected to the exhaust gas processor (5). The pressure reduction vaporization unit includes a pressure reduction heater (2) and a heat tracing inverted U-shaped tube (3) connected in series with the pressure reduction heater (2). The pressure reduction heater (2) and the heat tracing inverted U-shaped tube (3) are respectively connected to the vacuum pumping unit, the pressure reduction heater (2) is connected to the gas replacement unit, and the heat tracing inverted U-shaped tube (3) is connected to the venting unit.

2. The online sampling and injection system for liquefied gas according to claim 1, characterized in that: The pressure and flow rate regulating unit includes a pressure flow meter (17) and an injection regulating valve (18) disposed between the sampling section (1) and the pressure reducing vaporization unit.

3. The online sampling and injection system for liquefied gas according to claim 2, characterized in that: The vacuuming component includes a first tee (9) between the pressure reducing heater (2) and the heat tracing inverted U-shaped tube (3), a second tee (10) between the heat tracing inverted U-shaped tube (3) and the analyzer (4), the third end of the first tee (9) and the third end of the second tee (10) are respectively connected to a third tee (11), the third end of the third tee (11) is connected to the exhaust gas processor (5) through a vacuum pump (6), a first pneumatic valve (19) is provided between the third end of the first tee (9) and the third tee (11), and a second pneumatic valve (20) is provided between the third end of the third tee (11) and the vacuum pump (6).

4. The online sampling and injection system for liquefied gas according to claim 3, characterized in that: The gas replacement component includes a fourth tee (12) disposed between the first tee (9) and the heat-tracing inverted U-shaped pipe (3), and the third end of the fourth tee (12) is provided with a nitrogen replacement pipe (15) with a third pneumatic valve (21); A fifth three-way valve (13) is provided between the sample injection regulating valve (18) and the pressure reducing heater (2). The third end of the fifth three-way valve (13) is connected to the exhaust gas processor (5) through the displacement valve (16).

5. The online sampling and injection system for liquefied gas according to claim 3, characterized in that: The venting device includes a three-way valve (14) disposed between the heat-tracing inverted U-shaped pipe (3) and the second three-way valve (10). The third end of the three-way valve (14) is connected to the exhaust gas processor (5) through the first flow meter (24) and the fourth pneumatic valve (22).

6. The online sampling and injection system for liquefied gas according to claim 4, characterized in that: A secondary pressure reducing valve (7) is provided between the fourth tee (12) and the heat tracing U-shaped pipe (3).

7. The online sampling and injection system for liquefied gas according to claim 3, characterized in that: A second flow meter (25) and a fifth pneumatic valve (23) are sequentially provided between the second three-way valve (10) and the analyzer (4).

8. The online sampling and injection system for liquefied gas according to claim 1, characterized in that: It also includes a PLC control system (8), whose signal input terminal is connected to the pressure flow meter (17), the first flow meter (24), the second flow meter (25), the pressure sensor (26) and the differential pressure sensor (27), and whose signal output terminal is connected to the injection regulating valve (18), the fifth pneumatic valve (23), the fourth pneumatic valve (22), the second pneumatic valve (20) and the secondary pressure reducing valve (7); The pressure sensor (26) is installed on the pressure reducing heater (2), and the differential pressure sensor (27) is installed on the secondary pressure reducing valve (7).

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