A hydrogen leakage risk assessment method and a hydrogen leakage risk assessment device

Abstract

The application provides a hydrogen leakage risk assessment method and device, comprising collecting a gas sample to be measured; measuring the propagation speed of ultrasonic waves in the gas sample to be measured; iteratively calculating the volume fraction of hydrogen in the gas sample to be measured according to the propagation speed and a pre-constructed mixed gas sound velocity model; and evaluating the leakage risk of the gas sample to be measured according to the volume fraction. The application can precisely and efficiently evaluate the hydrogen leakage risk.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen leak detection technology, specifically relating to a hydrogen leak risk assessment method and a hydrogen leak risk assessment device. Background Technology

[0002] With the booming development of the hydrogen energy industry, the safety of hydrogen storage and transportation has become a key consideration in the field due to its flammable, explosive, and low-density properties. Hydrogen leaks can cause major accidents such as fires and explosions; therefore, accurate and efficient detection of hydrogen leaks is one of the core technological requirements for ensuring the safe operation of hydrogen energy equipment. Relevant technologies can be found in documents such as "Hydrogen Energy Safety Technology and Standards," which provide a detailed explanation of safety issues in hydrogen energy applications and the current status of existing detection technologies.

[0003] Currently, common methods for detecting hydrogen leaks mainly fall into two categories:

[0004] One method is the electrochemical sensor detection method. This method utilizes electrochemical principles, using a sensor to generate an electrical signal through a chemical reaction with hydrogen gas to detect hydrogen leaks. While it has a certain level of sensitivity, it has significant drawbacks: the sensor's lifespan is limited by its chemical properties, requiring frequent replacements and increasing long-term operating costs; furthermore, it is susceptible to interference from other reducing gases in the environment. For example, in an environment containing small amounts of carbon monoxide, it may misjudge the hydrogen concentration, leading to inaccurate detection results.

[0005] The second method is catalytic combustion detection. This method relies on the combustion of hydrogen in the presence of a catalyst, causing changes in the temperature and resistance of the detection element to determine a leak. However, this method is sensitive to environmental conditions. In high-temperature, high-humidity, or unstable airflow environments, the activity of the catalyst is easily affected, making it difficult to guarantee detection accuracy. Furthermore, it can only determine whether hydrogen is leaking, but cannot quantitatively analyze the ratio of hydrogen to air in the leaked gas, making it difficult to meet the needs of comprehensively understanding the leak situation and accurately assessing safety risks.

[0006] In summary, existing hydrogen leak detection methods are insufficient in terms of accuracy, stability, comprehensive functionality, and cost control, making them unsuitable for the complex requirements of detection technology in scenarios such as safety inspections and commissioning of hydrogen energy equipment. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method and device for assessing hydrogen leakage risk, so as to accurately and efficiently assess the risk of hydrogen leakage.

[0008] In a first aspect, the present invention provides a method for assessing the risk of hydrogen leakage, the method comprising the following steps:

[0009] Collect gas samples to be tested;

[0010] Measure the propagation speed of ultrasonic waves in a gas sample to be tested;

[0011] The volume fraction of hydrogen in the gas sample to be tested is calculated iteratively based on the propagation speed and a pre-built mixed gas sound velocity model. The mixed gas sound velocity model is based on the difference in the propagation speed of ultrasound in pure hydrogen and background gas.

[0012] The risk of leakage of the gas sample to be tested is assessed based on its volume fraction.

[0013] Optionally, the expression for the sound velocity model of the mixed gas is:

[0014]

[0015] in, This indicates the pre-observed propagation speed of ultrasound in pure hydrogen gas. This indicates the propagation speed of the pre-acquired ultrasound waves in the background gas. This indicates the volume fraction of hydrogen gas. This indicates the speed at which ultrasound propagates in a mixture of hydrogen and background gas.

[0016] Optionally, the background gas can be pure oxygen, pure nitrogen, or air.

[0017] Optionally, based on the propagation speed and a pre-built sound velocity model of the mixed gas, the volume fraction of hydrogen in the gas sample to be tested is calculated iteratively, including:

[0018] when and When the difference between the values ​​is less than a preset threshold, the volume fraction of hydrogen in the gas sample to be tested is determined to be 0, indicating that the gas sample to be tested does not contain hydrogen.

[0019] when and When the difference between them is less than the preset threshold, the volume fraction of hydrogen in the gas sample to be tested is determined to be 1, indicating that the gas sample to be tested is pure hydrogen.

[0020] when Between , Between, and and When the difference between the values ​​exceeds a preset threshold, an iterative algorithm is used to calculate the hydrogen gas integral.

[0021] Optionally, after measuring the propagation speed of ultrasound in the gas sample to be tested, and before iteratively calculating the volume fraction of hydrogen in the gas sample to be tested based on the propagation speed and a pre-built mixed gas sound velocity model, the method further includes:

[0022] Construct environmental compensation factors based on temperature or pressure;

[0023] The propagation speed is corrected using environmental compensation factors.

[0024] Secondly, the present invention provides a hydrogen leakage risk assessment device, including an inlet pipe, a filter layer, a sealed cavity, an ultrasonic generator, an ultrasonic receiver, a propagation speed measuring chip, a microprocessor, a temperature sensor, a pressure sensor, and a display; which cooperate with each other to perform the above-described hydrogen leakage risk assessment method.

[0025] Optionally, the air inlet pipe is used to transfer the gas sample to be tested into the sealed cavity and has a built-in filter layer to filter impurities of different particle sizes in the gas sample to be tested.

[0026] An ultrasonic generator, ultrasonic receiver, velocity measurement chip, microprocessor, temperature sensor, and pressure sensor are housed inside a sealed cavity. The ultrasonic generator and ultrasonic receiver are coaxially aligned, and the microprocessor is communicatively connected to the velocity measurement chip, display, temperature sensor, and pressure sensor. The velocity measurement chip measures the propagation speed of ultrasonic waves in the gas sample under test. The microprocessor constructs an environmental compensation factor based on the temperature and pressure data collected by the temperature and pressure sensors, corrects the propagation speed using the environmental compensation factor, and iteratively calculates the volume fraction of hydrogen in the gas sample under test based on the corrected propagation speed and a pre-built mixed gas sound velocity model. It then assesses the leakage risk of the gas sample under test based on the volume fraction. The display shows the leakage risk assessment results from the microprocessor.

[0027] Optionally, the speed measurement chip uses the TDC-GP30 high-precision time-to-digital converter chip.

[0028] Optionally, the microprocessor uses an embedded processor with an ARM Cortex-M7 core.

[0029] Optionally, the filter media in the filter layer may be made of polytetrafluoroethylene (PTFE), which is resistant to hydrogen corrosion.

[0030] The beneficial effects of this invention are:

[0031] The hydrogen leakage risk assessment method provided by this invention calculates the hydrogen gas integral number through sound velocity iteration, which solves the shortcomings of traditional methods that rely on electrochemical / catalytic combustion sensors and can only qualitatively determine whether a hydrogen leakage has occurred, but cannot quantify the degree of hydrogen leakage. This method enables accurate and efficient assessment of hydrogen leakage risk. Attached Figure Description

[0032] Figure 1 This is a flowchart of a hydrogen leakage risk assessment method in one embodiment of this application. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] like Figure 1 As shown, the hydrogen leakage risk assessment method provided by the present invention includes the following steps:

[0035] Step 11: Collect the gas sample to be tested.

[0036] In this embodiment of the invention, the gas sample is directly extracted from the environment by the device. The invention can use an extraction pump or piston mechanism to continuously draw gas from the sampling port into the detection chamber for detection. Specific implementation methods for the gas sampling method can be found in the structure of a pump-driven gas detector.

[0037] Step 12: Measure the propagation speed of ultrasound in the gas sample to be tested.

[0038] Step 13: Based on the propagation speed and the pre-constructed mixed gas sound speed model, iteratively calculate the volume fraction of hydrogen in the gas sample to be tested.

[0039] The mixed-gas sound velocity model is constructed based on the difference in the propagation speed of ultrasound in pure hydrogen and background gas. In this embodiment of the invention, the background gas is pure oxygen, pure nitrogen, or air. In other embodiments of the invention, the background gas may also be other gases that do not contain hydrogen (e.g., carbon dioxide or inert gases).

[0040] Taking pure oxygen as the background gas as an example, measurements show that the propagation speed of ultrasound in pure hydrogen is 1320 m / s at room temperature (25℃), while the propagation speed of ultrasound in pure oxygen is 316 m / s.

[0041] Specifically, the expression for the sound velocity model of a mixed gas is:

[0042]

[0043] in, This indicates the pre-observed propagation speed of ultrasound in pure hydrogen gas. This indicates the propagation speed of the pre-acquired ultrasound waves in the background gas. This indicates the volume fraction of hydrogen gas. This indicates the speed at which ultrasound propagates in a mixture of hydrogen and background gas.

[0044] The speed of ultrasonic wave propagation in the gas sample to be tested was measured. In this case, , It is known, through iteration The value of can ultimately determine the volume fraction of hydrogen.

[0045] Step 14: Assess the leakage risk of the gas sample to be tested based on its volume fraction.

[0046] In one feasible implementation, the volume fraction of hydrogen can be mapped to three levels of risk (safe, warning, dangerous) based on the flammability of hydrogen.

[0047] Specifically, when the volume fraction of hydrogen is less than 2%, the leakage risk assessment result is safe, as the lower flammability limit of hydrogen has not been reached; when the volume fraction of hydrogen is between 2% and 4%, the leakage risk assessment result is warning, as the hydrogen is within the flammable and explosive range; when the volume fraction of hydrogen is higher than 4%, the leakage risk assessment result is dangerous, as high concentrations of hydrogen can easily trigger detonation.

[0048] In another feasible embodiment of the present invention, after measuring the propagation speed of ultrasound in the gas sample to be tested, and before iteratively calculating the volume fraction of hydrogen in the gas sample to be tested based on the propagation speed and a pre-constructed mixed gas sound velocity model, the method further includes:

[0049] Environmental compensation factors are constructed based on temperature or pressure. Specifically, the environmental compensation factor constructed based on temperature is... ,in, The reference temperature is represented by T, and the actual temperature measured by the temperature sensor is represented by T. The environmental compensation factor based on pressure is... ,in, P represents the reference pressure, and P represents the actual pressure measured by the pressure sensor.

[0050] The hydrogen leakage risk assessment method provided by this invention uses an environmental compensation factor to correct for the propagation speed. Specifically, it is calculated using a formula... The corrected propagation speed is obtained. By iteratively calculating the hydrogen gas integral number using the speed of sound, the traditional method, which relies on electrochemical / catalytic combustion sensors, can only qualitatively determine whether a hydrogen leak has occurred, but cannot quantify the extent of the leak. This enables a precise and efficient assessment of hydrogen leak risk.

[0051] Example 1

[0052] A 5-meter-long, 10-mm-diameter hydrogen delivery hose from a hydrogen production laboratory was selected as the test object. Three leak points were artificially created on the hose (by inserting syringe needles of different diameters into the hose), with leak diameters of 0.2mm, 0.5mm, and 1mm, respectively.

[0053] An electrochemical sensor detection method was employed: a high-precision electrochemical hydrogen sensor was selected from the market and installed at a suitable location around the pipeline according to standard installation specifications. When a leak began at a 0.2mm leak point, the sensor detected the change in hydrogen concentration and issued an alarm after 5 minutes. During the detection process, the detected value fluctuated within ±5% due to interference from trace amounts of carbon monoxide gas in the environment. For a 0.5mm leak point, the sensor detected the leak and issued an alarm after 2 minutes, with relatively stable detected values ​​and less susceptibility to environmental interference. For a 1mm leak point, the sensor responded and issued an alarm within 1 minute, demonstrating good overall detection performance. However, the detection accuracy of this electrochemical sensor decreased to some extent after prolonged use. After one month of continuous monitoring, the error in hydrogen concentration detection increased to ±10%, and the sensor has a limited lifespan, requiring periodic replacement and increasing maintenance costs.

[0054] The hydrogen leak risk assessment device provided by this invention: After installation and commissioning, the device is put into operation. For a 0.2mm leak point, the time from the start of the leak to the detection alarm is 5 seconds, and the detected value is stable and unaffected by changes in other gases or temperature; for a 0.5mm leak point, the detection alarm takes 3 seconds; for a 1mm leak point, gas density fluctuations can be detected and an alarm is triggered in just 2 seconds. Furthermore, the hydrogen leak risk assessment device provided by this invention can accurately provide hydrogen concentration and leak amount estimation data, while electrochemical sensors can only qualitatively determine whether a leak has occurred.

[0055] Example 2

[0056] At the outdoor hydrogen energy equipment commissioning site, four leakage scenarios were simulated: valve micro-leakage (0.3L / min), flange surface leakage (1L / min), pipeline crack leakage (3L / min), and joint breakage leakage (8L / min) in a light wind environment, with an ambient temperature fluctuation of 5℃ and a small amount of dust present.

[0057] Catalytic combustion detection method: Uses an industrial-grade catalytic combustion detector (range 0-4%VOL, accuracy ±3%FS). Valve micro-leakage: Stable detection requires 12 minutes; affected by light winds, concentration readings fluctuate by ±10%; Flange surface leakage: Response time 6 minutes, deviation ±5%; Pipeline crack leakage: Response time 3 minutes, deviation ±4%; Joint breakage leakage: Response time 1.5 minutes, deviation ±3%. However, the detector is sensitive to dust; the sensor needs to be cleaned every 2 hours, and when locating a leak, it is necessary to repeatedly stay in the suspected area (approximately 1 minute per point) to confirm the location.

[0058] The hydrogen leakage risk assessment method and device provided by this invention features a dust-resistant design (the filter layer intercepts impurities with a particle size >1μm). For valve micro-leakage: location is achieved in 4 minutes during the moving scan, with a concentration deviation of ±10%; for flange surface leakage: location is achieved in 3 minutes, with a deviation of ±8%; for pipeline crack leakage: location is achieved in 2 minutes, with a deviation of ±7%; for joint breakage leakage: location is achieved in 1 minute, with a deviation of ±6%. The entire process requires no interruption and can be continuously scanned. A comprehensive leak detection within a 50㎡ test area can be completed in just 25 minutes, with no need for frequent maintenance.

[0059] As can be seen from the above comparative examples, compared with the traditional electrochemical sensor detection method and catalytic combustion detection method, the hydrogen leakage risk assessment device provided by the present invention has significant advantages in detection speed, anti-interference ability, detection accuracy, and adaptability to different leakage degrees and leakage orifice sizes, and can realize hydrogen leakage detection more efficiently, accurately and stably.

[0060] The hydrogen leakage risk assessment device provided by the present invention will be described below.

[0061] This invention provides a hydrogen leak risk assessment device, including an inlet pipe, a filter layer, a sealed cavity, an ultrasonic generator, an ultrasonic receiver, a propagation speed measuring chip, a microprocessor, a temperature sensor, a pressure sensor, and a display; the components cooperate with each other to perform the above-described hydrogen leak risk assessment method.

[0062] The inlet pipe is used to transport the gas sample to be tested into the sealed cavity and has a built-in filter layer to filter impurities of different particle sizes in the gas sample. In one feasible embodiment, the inlet pipe adopts a quick-connect coupling design to adapt to hydrogen systems or pipelines of different diameters. The pipe body can be made of 316L stainless steel with a gold-plated inner wall to prevent hydrogen permeation and surface adsorption. A built-in laminar flow rectifier ensures uniform and stable gas flow and reduces the impact of turbulence on subsequent sound velocity measurements. In this embodiment of the invention, the filter material in the filter layer is made of hydrogen-resistant polytetrafluoroethylene (PTFE).

[0063] An ultrasonic generator, ultrasonic receiver, velocity measurement chip, microprocessor, temperature sensor, and pressure sensor are housed inside a sealed cavity. The ultrasonic generator and ultrasonic receiver are coaxially aligned, and the microprocessor is communicatively connected to the velocity measurement chip, display, temperature sensor, and pressure sensor. The velocity measurement chip measures the propagation speed of ultrasonic waves in the gas sample under test. The microprocessor constructs an environmental compensation factor based on the temperature and pressure data collected by the temperature and pressure sensors, corrects the propagation speed using the environmental compensation factor, and iteratively calculates the volume fraction of hydrogen in the gas sample under test based on the corrected propagation speed and a pre-built mixed gas sound velocity model. It then assesses the leakage risk of the gas sample under test based on the volume fraction. The display shows the leakage risk assessment results from the microprocessor.

[0064] In one feasible implementation, ultrasonic transmission windows are provided at both ends of the cavity to ensure that the propagation of sound waves is not obstructed;

[0065] In one feasible implementation, the ultrasonic generator and the ultrasonic receiver are piezoelectric ceramic composite ultrasonic transducers with a center frequency of 40kHz±0.5kHz. The ultrasonic generator and the ultrasonic receiver are separated by a fixed distance L (e.g., 150mm). The ultrasonic generator emits a 128-cycle Hanning window modulated sine wave, and the ultrasonic receiver captures the arriving sound wave signal.

[0066] In one feasible implementation, the speed measurement chip uses a TDC-GP30 high-precision time-to-digital converter chip with a resolution of 8ps and an accuracy of ±20ps.

[0067] In one feasible implementation, the microprocessor is an embedded processor with an ARM Cortex-M7 core and a clock speed of 300MHz.

[0068] It should be noted that the information interaction and execution process of the above-mentioned device are based on the same concept as the method embodiments of this application. For details on their specific functions and technical effects, please refer to the method embodiments section, which will not be repeated here. Those skilled in the art will understand that, for the sake of convenience and brevity, the above-mentioned division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments 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. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, which will not be repeated here.

[0069] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0070] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A method for assessing the risk of hydrogen leakage, characterized in that, include: Collect gas samples to be tested; Measure the propagation speed of ultrasonic waves in the gas sample to be tested; Based on the propagation speed and the pre-constructed mixed gas sound velocity model, the volume fraction of hydrogen in the gas sample to be tested is calculated iteratively; the mixed gas sound velocity model is constructed based on the difference in the propagation speed of ultrasound in pure hydrogen and background gas; the expression of the mixed gas sound velocity model is: ;in, This indicates the pre-observed propagation speed of ultrasound in pure hydrogen gas. This indicates the propagation speed of the pre-acquired ultrasound waves in the background gas. This indicates the volume fraction of hydrogen gas. This indicates the speed at which ultrasound propagates in a mixture of hydrogen and a background gas; the background gas is pure oxygen, pure nitrogen, or air. The step of iteratively calculating the volume fraction of hydrogen in the gas sample to be tested based on the propagation speed and a pre-built mixed gas sound speed model includes: when and When the difference between the values ​​is less than a preset threshold, the volume fraction of hydrogen in the gas sample to be tested is determined to be 0, indicating that the gas sample to be tested does not contain hydrogen; when... and When the difference between the values ​​is less than the preset threshold, the volume fraction of hydrogen in the gas sample to be tested is determined to be 1, indicating that the gas sample to be tested is pure hydrogen; when... Between , Between, and and When the difference between the values ​​is greater than the preset threshold, an iterative algorithm is used to calculate the hydrogen gas integral. After measuring the propagation speed of the ultrasonic wave in the gas sample to be tested, and before iteratively calculating the volume fraction of hydrogen in the gas sample to be tested based on the propagation speed and the pre-constructed mixed gas sound speed model, the method further includes: constructing an environmental compensation factor based on temperature or pressure; and using the environmental compensation factor to correct the propagation speed. The leakage risk of the gas sample to be tested is assessed based on the volume fraction.

2. A hydrogen leakage risk assessment device, characterized in that, It includes an intake pipe, a filter layer, a sealed cavity, an ultrasonic generator, an ultrasonic receiver, a propagation velocity measurement chip, a microprocessor, a temperature sensor, a pressure sensor, and a display; these components work together to perform the hydrogen leakage risk assessment method as described in claim 1.

3. The hydrogen leakage risk assessment device according to claim 2, characterized in that, The air inlet pipe is used to transmit the gas sample to be tested into the sealed cavity, and has a built-in filter layer for filtering impurities of different particle sizes in the gas sample to be tested. The ultrasonic generator, ultrasonic receiver, velocity measurement chip, microprocessor, temperature sensor, and pressure sensor are housed within a sealed cavity. The ultrasonic generator and receiver are coaxially aligned, and the microprocessor is communicatively connected to the velocity measurement chip, the display, the temperature sensor, and the pressure sensor. The velocity measurement chip measures the propagation speed of ultrasonic waves in the gas sample under test. The microprocessor constructs an environmental compensation factor based on the temperature and pressure data collected by the temperature and pressure sensors, corrects the propagation speed using this factor, and iteratively calculates the volume fraction of hydrogen in the gas sample under test based on the corrected propagation speed and a pre-built mixed gas sound velocity model. It then assesses the leakage risk of the gas sample based on this volume fraction. The display shows the leakage risk assessment results from the microprocessor.

4. The hydrogen leakage risk assessment device according to claim 3, characterized in that, The speed measurement chip uses the TDC-GP30 high-precision time-to-digital converter chip.

5. The hydrogen leakage risk assessment device according to claim 4, characterized in that, The microprocessor is an embedded processor with an ARM Cortex-M7 core.

6. The hydrogen leakage risk assessment device according to claim 5, characterized in that, The filter media in the filter layer is made of polytetrafluoroethylene, which is resistant to hydrogen corrosion.

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