Measurement method and apparatus for hydrogen sulfide concentration in natural gas

Abstract

A measurement method and apparatus for hydrogen sulfide concentration in natural gas. The measurement apparatus comprises a detector tube, a direct current power supply, a current detector, and a flow detector. The detector tube is filled with a hydrogen sulfide detection indicator, and two ends of the detector tube are connected to the direct current power supply and the current detector; a preset mass of natural gas containing hydrogen sulfide at a known concentration is introduced into the detector tube to undergo a color change reaction with the hydrogen sulfide detection indicator, and when a length of the color change reaction reaches a preset length, a reading change amount ΔA of the current detector is recorded; then natural gas under test is introduced into another detector tube, and when the reading of the current detector changes by ΔA, the volume of the introduced natural gas under test is determined by means of the flow detector; and finally, the hydrogen sulfide concentration in the natural gas under test is calculated on the basis of the preset mass and the volume of the natural gas under test.

Description

A method and apparatus for detecting hydrogen sulfide concentration in natural gas

[0001] Related applications

[0002] This application claims Chinese Patent Application No. 202411630497.5, filed on November 14, 2024, and incorporates the disclosure of the aforementioned patent application as part of this application. Technical Field

[0003] This specification relates to the field of natural gas detection technology, and in particular to a method and apparatus for detecting hydrogen sulfide concentration in natural gas. Background Technology

[0004] Hydrogen sulfide, carbon dioxide, and water content are the most common detection indicators in natural gas development, purification, storage, and transportation, resulting in high demand. Current offline detection methods require various specialized analytical instruments, sampling, and cumbersome chemical analysis, which are time-consuming, labor-intensive, and costly. This leads to significant equipment, personnel, and time costs at every stage of natural gas production, storage, transportation, utilization, and performance evaluation of purification units. Online analysis saves manpower, but the equipment costs are high, and extensive maintenance is required, including regular calibration and carrier gas replacement. Therefore, it cannot currently replace offline analysis.

[0005] Existing gas detection tube technology, also known as direct-reading detection tubes, consists of a silica or alumina carrier filled with a detection reagent. The outer surface of the tube is marked with graduations indicating gas concentration. When the gas being tested passes through the carrier, it reacts chemically with the reagent, causing a color change. In existing technologies, sample introduction is achieved manually via a suction component within the tube. Inconsistencies in operation between different personnel and even repeated measurements by the same person lead to poor repeatability and reproducibility. Furthermore, environmental factors such as temperature and atmospheric pressure affect the sample volume, resulting in significant measurement uncertainty. Moreover, existing technologies rely primarily on manual or visual determination of the color change location. However, issues such as indistinct color changes and inconsistent color-change interface lengths within the tube cause errors in each reading, leading to inaccurate results and low measurement accuracy. Additionally, manual reading suffers from inconsistent standards, resulting in poor comparability and repeatability of test results. Summary of the Invention

[0006] This manual addresses the shortcomings of existing methods for detecting hydrogen sulfide concentration in natural gas, which primarily rely on manual determination of the color change location or visual techniques. These methods often result in inaccurate readings, significant errors, and low measurement accuracy. The embodiments in this manual provide a method and apparatus for detecting hydrogen sulfide concentration in natural gas, avoiding the problems of inconsistent standards, poor comparability, and poor repeatability of test results associated with manual readings.

[0007] To solve the above-mentioned technical problems, the first aspect of this specification provides a method for detecting hydrogen sulfide concentration in natural gas, applicable to a detection device, the detection device comprising a detection tube, a DC power supply, a current detector and a flow detector, wherein the detection tube is filled with a hydrogen sulfide detection indicator, and the two ends of the detection tube are connected to the DC power supply and the current detector;

[0008] A pre-set mass of natural gas containing hydrogen sulfide of known concentration is introduced into the detection tube of a detection device to react with the hydrogen sulfide detection indicator. When the length of the color change reaction reaches a pre-set length, the change in the reading ΔA of the current detector is recorded.

[0009] The natural gas to be tested is introduced into the detection tube of another detection device or another detection tube of the detection device. When the reading of the current detector changes by ΔA, the volume of the natural gas to be tested introduced into the detection tube is determined according to the flow detector.

[0010] The concentration of hydrogen sulfide in the natural gas to be tested is calculated based on the preset mass and the volume of the natural gas to be tested.

[0011] A second aspect of this specification provides a device for detecting hydrogen sulfide concentration in natural gas. The device includes a detection tube, a DC power supply, a current detector, and a flow detector. The detection tube is filled with a hydrogen sulfide detection indicator, and both ends of the detection tube are connected to the DC power supply and the current detector. The device for detecting hydrogen sulfide concentration in natural gas includes:

[0012] A standard reaction module is used to pass a preset mass of natural gas containing hydrogen sulfide of known concentration into the detection tube of a detection device to react with the hydrogen sulfide detection indicator to produce a color change reaction. When the length of the color change reaction reaches a preset length, the change in the reading ΔA of the current detector is recorded.

[0013] The detection reaction module is used to introduce the natural gas to be tested into the detection tube of another detection device or another detection tube of the detection device. When the reading of the current detector changes by ΔA, the volume of the natural gas to be tested introduced into the detection tube is determined according to the flow detector.

[0014] The hydrogen sulfide concentration calculation module is used to calculate the hydrogen sulfide concentration in the natural gas to be tested based on the preset mass and the volume of the natural gas to be tested.

[0015] A third aspect of this specification provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the methods described in any of the foregoing embodiments.

[0016] A fourth aspect of this specification provides a computer-readable storage medium storing a computer program that, when executed by a processor of a computer device, implements the methods described in any of the foregoing embodiments.

[0017] The analytical method for detecting hydrogen sulfide concentration in natural gas provided in this specification involves analyzing the concentration of hydrogen sulfide-containing natural gas using a detection tube, a DC power supply, a current detector, and a flow detector within the detection device. The detection tube is filled with a hydrogen sulfide detection indicator, and both ends of the tube are connected to the DC power supply and the current detector. The detection tube is calibrated using a hydrogen sulfide gas standard substance of known concentration and preset mass. A certain amount of the hydrogen sulfide-containing standard substance is introduced into the detection tube to react with zinc oxide, causing a color change. Simultaneously, the resistance of the detection tube changes. When the length of the color change reaction reaches a preset length, the change in the current detector reading ΔA is recorded. Then, during natural gas detection, the natural gas to be tested is introduced into the detection tube of another detection device or another detection tube of the same device. When the change in the current detector reading reaches ΔA, the volume of the natural gas to be tested is determined based on the flow detector. The hydrogen sulfide concentration in the natural gas to be tested is then calculated based on the preset mass and the volume of the natural gas. This invention solves the problem in existing technologies where indistinct color changes and inconsistent color-changing interface lengths lead to errors in reading values ​​manually and visually during multiple tests. By using a current detector, the method eliminates the need for multiple readings of the detection tube, reduces errors in each reading, and improves the accuracy of hydrogen sulfide concentration detection in natural gas.

[0018] To make the above and other objects, features and advantages of this specification more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments or prior art of this specification, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 shows a first structural diagram of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0021] Figure 2 shows a flowchart of the analytical method of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification.

[0022] Figure 3 shows a second structural diagram of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0023] Figure 4 shows a third structural diagram of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0024] Figure 5 shows a fourth structural diagram of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0025] Figure 6 shows a fifth structural diagram of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0026] Figure 7 shows a model structural diagram of the hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0027] Figure 8 shows a schematic diagram of sampling using existing detection tubes;

[0028] Figure 9 shows a schematic diagram of a hydrogen sulfide concentration detection device in natural gas according to an embodiment of this specification;

[0029] Figure 10 shows a structural diagram of a computer device according to an embodiment of this specification. Detailed Implementation

[0030] The technical solutions in the embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this specification, and not all embodiments. Based on the embodiments in this specification, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this specification.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, apparatus, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0032] This specification provides the operational steps of the methods described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many steps and does not represent the only execution order. In actual system or device products, the methods shown in the embodiments or figures can be executed sequentially or in parallel. The lines in Figures 1 to 7 of this specification are connecting pipelines used to detect the hydrogen sulfide concentration in natural gas. In the prior art, the method of reading the scale on the natural gas detection tube based on computer vision suffers from large errors and low measurement accuracy due to the unclear color change inside the detection tube and the inconsistent length of the color change interface. The method of reading the scale on the natural gas detection tube manually suffers from large errors, low measurement accuracy, inconsistent standards, and poor comparability and repeatability of test results due to the unclear color change inside the detection tube and the inconsistent length of the color change interface. Furthermore, in the prior art, the natural gas detection tube sample injection is achieved through manual control, which leads to problems of poor repeatability and repeatability of sample injection due to multiple measurements by the same person and different measurements by multiple people. In addition, environmental factors such as temperature and atmospheric pressure affect the sample volume, resulting in large measurement uncertainties.

[0033] To address the aforementioned technical problems, this specification provides a method for detecting hydrogen sulfide concentration in natural gas in some embodiments. This method is applicable to the detection device shown in Figure 1, which includes a detection tube, a DC power supply, a current detector, and a flow detector 6. In this embodiment, the detection tube is filled with a hydrogen sulfide detection indicator, and the two ends of the detection tube are connected to the DC power supply and the current detector. The steps of the detection method are shown in Figure 2.

[0034] Step 201: Pass a pre-set mass of natural gas containing hydrogen sulfide of known concentration into the detection tube of a detection device to react with the hydrogen sulfide detection indicator. When the length of the color change reaction reaches the pre-set length, record the change in the reading ΔA of the current detector.

[0035] Step 202: Pass the natural gas to be tested into the detection tube of another detection device or another detection tube of the detection device. When the reading of the current detector changes by ΔA, determine the volume of the natural gas to be tested in the detection tube according to the flow detector 6.

[0036] Step 203: Calculate the hydrogen sulfide concentration in the natural gas to be tested based on the preset mass and the volume of the natural gas to be tested.

[0037] The analytical method for detecting hydrogen sulfide concentration in natural gas provided in this manual involves analyzing the concentration of hydrogen sulfide in natural gas using a detection tube 3, a DC power supply, a current detector, and a flow detector 6. The detection tube 3 is filled with a hydrogen sulfide detection indicator, and both ends of the tube are connected to the DC power supply and the current detector. The detection tube is calibrated using a hydrogen sulfide gas standard substance of known concentration and preset mass. A certain amount of the hydrogen sulfide standard substance is introduced into the detection tube to react with zinc oxide, causing a color change. Simultaneously, the resistance of the detection tube changes. When the color change reaches a preset length, the change in the current detector reading ΔA is recorded. Then, during natural gas detection, the natural gas to be tested is introduced into the detection tube of another detection device or another detection tube of another detection device. When the change in the current detector reading reaches ΔA, the volume of the natural gas to be tested is determined based on the flow detector 6. Therefore, the hydrogen sulfide concentration in the natural gas to be tested is calculated based on the preset mass and the volume of the natural gas to be tested. This invention solves the problem in existing technologies where indistinct color changes and inconsistent color-changing interface lengths lead to errors in reading values ​​manually and visually during multiple tests. By using a current detector, the method eliminates the need for multiple readings of the detection tube, reduces errors in each reading, and improves the accuracy of hydrogen sulfide concentration detection in natural gas.

[0038] In another embodiment of this specification, the detection device further includes: a pressure-resistant chamber 5 and a pressure regulator 4;

[0039] The first open end of the pressure-resistant cavity 5 is used to fix the detection tube 3; the second open end of the pressure-resistant cavity 5 is connected to the internal cavity of the pressure-resistant cavity 5, and is used to connect to the natural gas injection system and to connect to the flow detector 6 through the pressure regulator 4.

[0040] Introducing natural gas into the detection tube includes:

[0041] Connect natural gas to the second opening end of the pressure-resistant chamber 5 and the opening end of the detection tube. After the pressure-resistant chamber 5 is filled with natural gas, disconnect the connection between the natural gas and the second opening end of the pressure-resistant chamber 5.

[0042] Turn on pressure regulator 4 to create a pressure difference between the left and right ends of the detection tube, adjust the injection flow rate to the predetermined value, and turn on flow detector 6.

[0043] This application, by setting up a detection tube, a pressure-resistant cavity 5, and a pressure regulator 4, with natural gas component detection reagents in the detection tube and the open end of the detection tube for connection to the natural gas injection system; the first open end of the pressure-resistant cavity 5 for fixing the detection tube; and the second open end of the pressure-resistant cavity 5 connecting to the internal cavity of the pressure-resistant cavity 5 for connection to the natural gas injection system and for connection to the flow detector 6 via the pressure regulator 4, can realize automatic natural gas injection, improve repeatability, reduce the difficulty of injection operation, and reduce environmental impact.

[0044] In another embodiment of this specification, as shown in FIG3, the detection device further includes: a first control valve 1; wherein, the first control valve 1 has an input port, a first output port and a second output port, the input port of the first control valve 1 is used to connect natural gas, the first output port of the first control valve 1 is connected to the open end of the detection tube through a first pipeline, and the second output port of the first control valve 1 is connected to the second open end of the pressure-resistant cavity 5 through a second pipeline.

[0045] The second opening end for connecting natural gas to the pressure-resistant cavity 5 and the opening end for the detection tube include:

[0046] Open the first and second output ports of the first control valve 1 to allow natural gas to enter the first pipeline and then enter the pressure-resistant chamber 5 through the second pipeline.

[0047] The detection tube contains a natural gas component detection reagent, and its open end is connected to the natural gas injection system. Specifically, the natural gas components include, but are not limited to, hydrogen sulfide and carbon dioxide. The detection reagent is determined based on the analyte; different analytes and different detection reagents will produce different color changes, which this manual does not limit. The natural gas in the injection system is depressurized and / or departiculate-treated natural gas. In specific implementations, it can also be pressurized natural gas, i.e., natural gas maintained at the same pressure as in the natural gas transport pipeline. In specific implementations, the open end of detection tube 3 is connected to the natural gas injection system via a silanized pipeline.

[0048] Furthermore, as shown in Figure 4, the detection device also includes: a second control valve 2, which is connected to a first pipeline near the open end of the detection tube;

[0049] After disconnecting the natural gas from the second opening of the pressure-resistant chamber 5, the following steps are also included:

[0050] Open the second control valve 2 to clean the first pipeline.

[0051] This embodiment avoids the impact of residual substances in the pipeline on detection accuracy by cleaning the first pipeline before detection. In some embodiments, when the natural gas chemical metering detection device includes a third control valve 7, as shown in Figure 5, the detection device further includes: a third control valve 7, one end of which is connected to the pipeline between the second output port of the first control valve 1 and the second opening end of the pressure-resistant chamber 5 via a tee fitting; the other end of the third control valve 7 is connected to a recovery device;

[0052] After obtaining the hydrogen sulfide concentration, the following steps are also included:

[0053] Open the third control valve 7 to recover the natural gas in the pressure chamber 5.

[0054] This embodiment improves the safety of the device and reduces harm to the human body by recovering natural gas from the pressure-resistant chamber 5.

[0055] In another embodiment of this specification, as shown in FIG6, the detection device further includes: a fourth control valve 8.

[0056] One end of the fourth control valve 8 is connected to the pipeline between the second output port of the first control valve 1 and the second opening end of the pressure-resistant cavity 5 via a three-way fitting; the other end of the fourth control valve 8 is connected to an air pumping device.

[0057] The method also includes:

[0058] Open the fourth control valve 8 to pump air into the pressure-resistant chamber 5 using the air pumping device. The cleaning of the pressure-resistant chamber 5 is completed by repeatedly opening the third control valve 7 and the fourth control valve 8.

[0059] In practice, the above steps can be performed before the natural gas to be tested is introduced, or after the natural gas is recovered. This embodiment can avoid the impact of residual substances in the pressure-resistant chamber 5 on the detection accuracy.

[0060] In this embodiment of the specification, reading the flow detector 6 to obtain the volume of the incoming natural gas to be measured includes:

[0061] The same batch of testing equipment was used to repeat the above test on the same natural gas to be tested multiple times, and the volume of the natural gas to be tested was recorded. The hydrogen sulfide concentration in the multiple natural gas to be tested was calculated using the recorded volumes of natural gas to be tested.

[0062] Calculate the average value of hydrogen sulfide concentration in multiple natural gas samples and use the average value as the result of hydrogen sulfide concentration in the natural gas sample.

[0063] Specifically, the indicator in the detection tube is zinc oxide. The detection tube is calibrated using a hydrogen sulfide gas standard of known concentration; that is, a 6 ppm hydrogen sulfide gas standard is passed into the detection tube, and when the current detector reading changes by 92 mA, the flow rate is recorded as 45.25 ml. After completing the measurement, further calibration with a gas standard is not required.

[0064] Samples were taken from the pressure gauge interface of the external pipeline of a natural gas purification plant for analysis. In order to compare the measurement results with the differences of existing measurement methods, the same batch of detection devices were used to repeat the above detection multiple times on the same natural gas to be tested within the same time period. The volume of the natural gas to be tested was recorded and the hydrogen sulfide concentration in the natural gas to be tested was calculated. The average value of the multiple detection results was calculated as the hydrogen sulfide concentration result of the natural gas to be tested.

[0065] In the embodiments of this specification, the detection device further includes a color sensor 9, which is disposed on the outside of the pressure-resistant cavity 5 and is used to detect the length of the color change reaction of the detection tube.

[0066] By setting a color sensor 9 on the outside of the pressure-resistant cavity 5, the color sensor 9 detects the color change of the detection tube at the sensing position. This manual can achieve point measurement. Specifically, point detection here refers to circular detection with a very small radius. Point detection can accurately sense whether there is a color change at the position. In contrast, existing visual detection is surface measurement, and the length of the color change interface on the detection surface is not uniform, making it impossible to accurately determine. The detection method using the color sensor 9 in this manual can improve the accuracy of color change detection compared to existing methods.

[0067] In another embodiment of this specification, the color sensor 9 includes a laser emitter 91 and a laser receiver 92.

[0068] The laser emitter 91 is located on one side of the pressure-resistant cavity 5 and is used to emit laser signals.

[0069] The laser receiver 92 is located on the other side of the pressure-resistant cavity 5 and is opposite to the laser transmitter 91, and is used to receive laser signals.

[0070] The laser receiver 92 is connected to the control device 10, which is used to determine whether a color change has occurred at the sensing position based on the laser signal received by the laser receiver 92.

[0071] The sensing position is the location where the laser emitted by the laser emitter 91 passes through the pressure-resistant cavity 5. When the sensing position changes color, the laser signal received by the laser receiver 92 decreases or increases, depending on the color produced by the reaction between the natural gas component detection reagent and the natural gas.

[0072] In the embodiments of this specification, when the color-changing reaction length reaches a preset length, the change in the reading ΔA of the recorded current detector includes:

[0073] The color sensor 9 is activated to monitor the reaction length. When the reaction length reaches the preset length, the resistance of the detection tube changes, and the reading of the current detector is recorded at the same time.

[0074] For example, a certain amount of standard substance containing hydrogen sulfide m (milligrams) is passed into the detection tube and reacts with zinc oxide to produce a color change reaction. The reaction length is 1 mm. At the same time, the resistance of the detection tube changes, and the reading of the current detector changes by ΔA (from A1 to A2). When measuring the hydrogen sulfide content in natural gas, when the reading of the current detector changes by ΔA, the flow detector 6 reads the volume v (m3) of the natural gas being measured.

[0075] To more clearly illustrate the technical solutions in this specification, two examples are provided below to describe the principles and features of this specification. These examples are only used to explain this specification and are not intended to limit its scope.

[0076] Samples were taken from the pressure gauge interface of the external pipeline of a natural gas purification plant for analysis. In order to compare the measurement results with the differences of existing measurement methods, the hydrogen sulfide content was determined using the technology in this manual, the traditional detection tube method, and the iodometric method in the same time period.

[0077] The technical testing method described in this manual involves connecting a silanized pipeline to a natural gas sample source (3.2 MPa), as shown in Figure 7. First control valve 1 and second control valve 2 are opened to purge the bypass of the sample inlet pipeline. Second control valve 2 is closed, and pressure regulator 4 is slowly opened. Natural gas enters the pressure-resistant chamber 5 of the detection tube from the right end, filling the sample inlet pipeline of the first control valve 1. Both ends of the detection tube are under natural gas source pressure, achieving pressure balance. Then, second control valve 2 is slowly opened to purge the sample inlet pipeline. Second control valve 2 is closed, and the pressure and flow stabilization system is activated. The pressure valve is adjusted to create a pressure difference between the left and right ends of the detection tube. Natural gas enters from the left end of the detection tube and flows out through pressure regulator 4. The sample inlet flow rate is adjusted to 92 ml / min. Flow detector 6 is activated, and sample inlet begins. When the current detector reading changes to 92 mA, the flow rate is read as 83.26 ml.

[0078] The above test was repeated five times using the same batch of test tubes, and the recorded flow rates were 81.31 ml, 82.45 ml, 82.73 ml, 83.46 ml, and 83.916 ml, respectively. Therefore, the hydrogen sulfide content measured in the natural gas produced by the natural gas purification plant was 3.26 ppm, 3.34 ppm, 3.291 ppm, 3.28 ppm, 3.25 ppm, and 3.23 ppm, respectively. Taking the average value of 3.28 ppm, the repeatability (RSD) was 1.13%.

[0079] The traditional measurement method using test tubes is as follows:

[0080] According to GB / T 19260.11-2014 "Determination of Sulfur Compounds in Natural Gas - Part 11: Determination of Hydrogen Sulfide Content by Colored Length Detector Tube Method", a Guangming Beichuan AP-20CT manual sampling pump and a Guangming Beichuan 120U detector tube (0.1-6.0 ppm) were used, as shown in Figure 8. Samples were taken and analyzed at the pressure gauge interface of the external pipeline of the same natural gas purification plant. 50 ml of sample was manually and slowly drawn. The color change length of the detector tube, from pale yellow to peach, was observed to be approximately 2.1 ppm. The above test was repeated 5 times using the same batch of detector tubes, with readings of 2.6 ppm, 1.6 ppm, 2.3 ppm, 1.7 ppm, and 3.0 ppm, respectively. The atmospheric pressure during measurement was 918.6 kPa, and the temperature was 21.3℃. According to the instruction manual for the test tube, the measured value = reading × 2 × 921.325 kPa / atmospheric pressure at the measurement point × temperature correction factor. The temperature correction factor corresponding to 21.3℃ is found to be 1.0. Therefore, the calculated values ​​for the six measurements are 4.32 ppm, 5.34 ppm, 3.291 ppm, 4.73 ppm, 3.491 ppm, and 6.17 ppm, with an average value of 4.55 ppm. The measurement repeatability (RSD) is 24%.

[0081] The hydrogen sulfide content was determined using the iodometric method as follows:

[0082] According to GB / T 19260.1-2023 Determination of Sulfur Compounds in Natural Gas Part 1: Determination of Hydrogen Sulfide Content by Iodometric Method, the original data and calculation results for sampling and calculation are as follows: A hydrogen sulfide sampling absorber was connected to the pressure gauge interface of the external pipeline of the same natural gas purification plant. 50 mL of zinc acetate solution was added to the absorber, and a rubber bulb was used to gently agitate the absorber inlet to allow some solution to enter the space below the glass orifice plate. All parts were tightly connected with a short rubber tube. The screw clamp was fully opened, and the sampling valve was slowly opened to fully displace the gas in the sampling conduit with the gas to be analyzed through the vent pipe. The flow detector reading was recorded as the initial reading for sampling. The screw clamp was adjusted to allow the gas to pass through the absorber at a flow rate of 430 mL / min. The sampling volumes for the two parallel tests were 150.000 L and 153.000 L, respectively. The gas temperature was recorded as 27.0 °C and the atmospheric pressure as 918.60 kPa. Remove the absorber, add 92 mL (or 20 mL) of iodine solution (2.5 g / L) using a pipette, then add 92 mL of hydrochloric acid solution. Attach the absorber head and gently agitate the solution at the absorber inlet with a bulb syringe to ensure thorough mixing. After reacting for 3 minutes, transfer the solution to a 250 mL iodine flask and titrate with sodium thiosulfate standard solution (0.09206 mol / L). Perform a blank test following the same procedure. The titrant volumes for the two tests were 3.0 mL and 3.05 mL, respectively. The calculated hydrogen sulfide concentrations for the two tests were 3.73 mg / m³ and 3.67 mg / m³, respectively. The average value was 3.70 mg / m³, which translates to a volume fraction of 2.62 ppm.

[0083] A comparison of the three measurement methods shows that the hydrogen sulfide measurement result using the method described in this manual is 3.28 ppm, with a deviation of 0.66 ppm from the iodometric titration result (2.62 ppm). The hydrogen sulfide measurement value using the traditional detection tube method is 4.55 ppm, with a deviation of 1.913 ppm from the iodometric titration result (2.62 ppm). This demonstrates that the accuracy of the measurement using the method described in this manual is significantly improved compared to the traditional detection tube method (at the 2.62 ppm measurement point, the deviation has been reduced from 1.913 ppm to 0.66 ppm). Regarding measurement precision, the RSD of six repeated measurements using the method described in this manual is 1.13%, compared to 24% for six repeated measurements using the traditional detection tube method, representing an improvement in repeatability of approximately 21 times.

[0084] In some embodiments of this specification, in addition to the analytical method of the hydrogen sulfide concentration detection device in natural gas according to the above embodiments, a hydrogen sulfide concentration detection device in natural gas is also provided, as shown in FIG9, including:

[0085] The detection device includes a detection tube, a DC power supply, a current detector, and a flow detector. The detection tube is filled with a hydrogen sulfide detection indicator, and its two ends are connected to the DC power supply and the current detector. The hydrogen sulfide concentration detection device in natural gas includes:

[0086] The standard reaction module 901 is used to pass a preset mass of natural gas containing hydrogen sulfide of known concentration into the detection tube of a detection device to react with the hydrogen sulfide detection indicator to produce a color change reaction. When the length of the color change reaction reaches the preset length, the change in the reading ΔA of the current detector is recorded.

[0087] The detection reaction module 902 is used to introduce the natural gas to be tested into the detection tube of another detection device or another detection tube of the detection device. When the reading of the current detector changes by ΔA, the volume of the natural gas to be tested introduced into the detection tube is determined according to the flow detector.

[0088] The hydrogen sulfide concentration calculation module 903 is used to calculate the hydrogen sulfide concentration in the natural gas to be tested based on the preset mass and the volume of the natural gas to be tested.

[0089] The analytical method for detecting hydrogen sulfide concentration in natural gas provided in this manual utilizes a detection tube, a pressure-resistant chamber, and a pressure regulator. The detection tube contains natural gas component detection reagents, and its open end is connected to the natural gas sampling system. The first open end of the pressure-resistant chamber secures the detection tube, while the second open end connects to the internal cavity of the chamber for connection to the natural gas sampling system and a flow detector via the pressure regulator. This enables automated natural gas sampling, improves repeatability, reduces operational difficulty, minimizes environmental impact, and avoids significant human error. Furthermore, by incorporating a color sensor located outside the pressure-resistant chamber, the color sensor detects the length of the color change reaction in the detection tube, enabling point measurement. Compared to existing visual surface measurement methods (which suffer from interface overlap and unclear interfaces), this method improves the accuracy of automated detection and avoids errors from manual readings. This invention solves the problems of wide and ambiguous color change interface, large reading errors, and poor measurement accuracy of suction injection in the determination of hydrogen sulfide in natural gas by existing detection tube methods. After the detection tube is calibrated for the first time, the need for calibration with gaseous standard substances is eliminated during measurement, improving measurement repeatability and accuracy. Furthermore, the structure described in this manual also enables online detection of natural gas.

[0090] In some embodiments of this specification, a computer device is also described, as shown in FIG10. Computer device 1002 may include one or more processors 1004, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. Computer device 1002 may also include any memory 1006 for storing information of any kind, such as code, settings, data, etc. Non-limitingly, for example, memory 1006 may include any type of RAM, any type of ROM, flash memory, hard disk, optical disk, etc. More generally, any memory can use any technology to store information. Further, any memory may provide volatile or non-volatile retention of information. Further, any memory may represent a fixed or removable component of computer device 1002. In one case, when processor 1004 executes associated instructions stored in any memory or combination of memories, computer device 1002 may perform any operation of the associated instructions. Computer device 1002 also includes one or more drive mechanisms 1008 for interacting with any memory, such as hard disk drive mechanisms, optical disk drive mechanisms, etc.

[0091] Computer device 1002 may further include an input / output module 1010 (I / O) for receiving various inputs (via input device 1012) and providing various outputs (via output device 1014). A specific output mechanism may include a presentation device 1016 and an associated graphical user interface 1018 (GUI). In other embodiments, the input / output module 1010 (I / O), input device 1012, and output device 1014 may be omitted, and the device may function solely as a computer device within a network. Computer device 1002 may also include one or more network interfaces 1020 for exchanging data with other devices via one or more communication links 1022. One or more communication buses 1024 couple the components described above together.

[0092] The communication link 1022 can be implemented in any way, such as via a local area network, a wide area network (e.g., the Internet), a point-to-point connection, or any combination thereof. The communication link 1022 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0093] This specification also provides a computer-readable storage medium storing a computer program that, when executed by a processor, performs the steps of the above-described method.

[0094] This specification also provides computer-readable instructions, wherein when a processor executes the instructions, the program therein causes the processor to perform the method of any of the foregoing embodiments.

[0095] It should be understood that in the various embodiments of this specification, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this specification.

[0096] It should also be understood that, in the embodiments of this specification, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this specification generally indicates that the preceding and following related objects have an "or" relationship.

[0097] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this specification can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of each example have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this specification.

[0098] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0099] In the several embodiments provided in this specification, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the couplings or direct couplings or communication connections shown or discussed may be indirect couplings or communication connections through some interfaces, devices, or units, or they may be electrical, mechanical, or other forms of connection.

[0100] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of the embodiments described in this specification, depending on actual needs.

[0101] Furthermore, the functional units in the various embodiments of this specification can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0102] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this specification, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this specification. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0103] This specification uses specific embodiments to illustrate the principles and implementation methods of this specification. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this specification. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this specification. Therefore, the content of this specification should not be construed as a limitation of this specification.

Claims

1. A method for detecting hydrogen sulfide concentration in natural gas, characterized in that, The detection device includes a detection tube, a DC power supply, a current detector, and a flow detector, wherein the detection tube is filled with hydrogen sulfide detection indicator, and the two ends of the detection tube are connected to the DC power supply and the current detector. A pre-set mass of natural gas containing hydrogen sulfide of known concentration is introduced into the detection tube of a detection device to react with the hydrogen sulfide detection indicator. When the length of the color change reaction reaches a pre-set length, the change in the reading ΔA of the current detector is recorded. The natural gas to be tested is introduced into the detection tube of another detection device or another detection tube of the detection device. When the reading of the current detector changes by ΔA, the volume of the natural gas to be tested introduced into the detection tube is determined according to the flow detector. The concentration of hydrogen sulfide in the natural gas to be tested is calculated based on the preset mass and the volume of the natural gas to be tested.

2. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 1, characterized in that, The detection device also includes: a pressure-resistant chamber and a pressure regulator; The first opening of the pressure-resistant cavity is used to fix the detection tube; the second opening of the pressure-resistant cavity is connected to the internal cavity of the pressure-resistant cavity and is used to connect to the natural gas injection system and to connect to the flow detector through the pressure regulator. Introducing natural gas into the detection tube includes: Connect natural gas to the second opening of the pressure-resistant chamber and the opening of the detection tube. Once the pressure-resistant chamber is filled with natural gas, disconnect the natural gas from the second opening of the pressure-resistant chamber. Turn on the pressure regulator to create a pressure difference between the left and right ends of the detection tube, and adjust the injection flow rate to a predetermined value. Enable the traffic detector.

3. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 2, characterized in that, The detection device further includes: a first control valve; wherein the first control valve has an input port, a first output port and a second output port, the input port of the first control valve is used to connect to natural gas, the first output port of the first control valve is connected to the open end of the detection tube through a first pipeline, and the second output port of the first control valve is connected to the second open end of the pressure-resistant cavity through a second pipeline; The second opening end for connecting natural gas to the pressure-resistant cavity and the opening end of the detection pipe include: Open the first and second output ports of the first control valve to allow natural gas to enter the first pipeline and then enter the pressure-resistant chamber through the second pipeline.

4. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 3, characterized in that, The detection device further includes: a second control valve, connected to a first pipeline near the open end of the detection tube; After disconnecting the natural gas from the second opening of the pressure-resistant cavity, the process further includes: Open the second control valve to clean the first pipeline.

5. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 3, characterized in that, The detection device further includes: a third control valve, one end of which is connected via a tee fitting to a pipeline between the second output port of the first control valve and the second opening end of the pressure-resistant cavity; the other end of the third control valve is connected to a recovery device; After obtaining the hydrogen sulfide concentration, the following steps are also included: The third control valve is opened to recover the natural gas in the pressure-resistant chamber.

6. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 5, characterized in that, The detection device further includes: a fourth control valve, One end of the fourth control valve is connected via a tee fitting to the pipeline between the second output port of the first control valve and the second opening end of the pressure-resistant cavity; the other end of the fourth control valve is connected to an air pump. The method further includes: The fourth control valve is opened, and air is pumped into the pressure-resistant cavity by the air pumping device. The pressure-resistant cavity is cleaned by repeatedly opening and closing the third control valve and the fourth control valve.

7. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 1, characterized in that, Reading the flow detector to obtain the volume of the natural gas to be tested includes: The same batch of testing equipment was used to repeatedly test the same natural gas to be tested, and the volume of the natural gas to be tested was recorded each time. The hydrogen sulfide concentration in the natural gas to be tested was calculated using the multiple recorded volumes of the natural gas to be tested. Calculate the average value of the hydrogen sulfide concentration in multiple natural gas samples to be tested, and use the average value as the result of the hydrogen sulfide concentration in the natural gas sample to be tested.

8. The method for detecting hydrogen sulfide concentration in natural gas as described in claim 2, characterized in that, The detection device further includes a color sensor, which is disposed on the outside of the pressure-resistant cavity, for detecting the length of the color change reaction of the detection tube.

9. A device for detecting hydrogen sulfide concentration in natural gas, characterized in that, The detection device includes a detection tube, a DC power supply, a current detector, and a flow detector. The detection tube is filled with a hydrogen sulfide detection indicator, and both ends of the detection tube are connected to the DC power supply and the current detector. The hydrogen sulfide concentration detection device in natural gas includes: A standard reaction module is used to pass a preset mass of natural gas containing hydrogen sulfide of known concentration into the detection tube of a detection device to react with the hydrogen sulfide detection indicator to produce a color change reaction. When the length of the color change reaction reaches a preset length, the change in the reading ΔA of the current detector is recorded. The detection reaction module is used to introduce the natural gas to be tested into the detection tube of another detection device or another detection tube of the detection device. When the reading of the current detector changes by ΔA, the volume of the natural gas to be tested introduced into the detection tube is determined according to the flow detector. The hydrogen sulfide concentration calculation module is used to calculate the hydrogen sulfide concentration in the natural gas to be tested based on the preset mass and the volume of the natural gas to be tested.

10. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 8.

11. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor of a computer device, it implements the method of any one of claims 1 to 8.

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