A deflagration and backfire test system and method for a hydrogen pipeline venting system

Abstract

The application discloses a hydrogen pipeline venting system deflagration and tempering test system and method, relates to the technical field of pipeline testing, and comprises a premixing and concentration adjusting system, an adjustable release system, an along-path temperature and pressure detection system and a visual tempering detection system. The premixing and concentration adjusting system is arranged to simulate the hydrogen-air premixing state in the venting pipeline caused by hydrogen valve internal leakage. The adjustable release system is arranged to simulate the hydrogen spontaneous combustion state under different release rates. The adjustable release system is arranged to test the influence of different pipe diameter specifications and pipe fitting setting modes on the pressure rise in the deflagration process. The along-path temperature and pressure detection system is arranged to test the spontaneous combustion condition in the venting pipeline and also to test the influence of different pipe diameters and pipe fitting structures of the venting pipeline on the deflagration overpressure. The visual tempering detection system is established to test the tempering scale after ignition and combustion, so as to provide a relief strategy.

Description

Technical Field

[0001] This invention relates to the field of pipeline testing technology, and more specifically to the field of a test system and method for deflagration and backfire testing of hydrogen pipeline venting systems. Background Technology

[0002] Hydrogen, as a key development direction for new energy sources, boasts significant advantages over traditional fossil fuels, including high calorific value, environmentally friendly combustion products, wide availability, and renewability. It is hailed as a clean energy source of the future and will become a new pathway for humanity to address increasingly severe energy and environmental challenges. Due to geographical differences in hydrogen production and utilization, medium- and long-distance hydrogen transportation is gradually becoming a crucial link in the efficient utilization of hydrogen energy, with pipeline transportation being a popular choice and a promising development direction.

[0003] Compared to natural gas, hydrogen has a calorific value of about one-third and a density of about one-eighth that of natural gas. Hydrogen also has a lower ignition energy, making it highly susceptible to spontaneous combustion. Furthermore, hydrogen burns rapidly, has a wide explosive concentration range, and readily combusts after ignition, with a relatively large proportion of the gas participating in the combustion. Typically, hydrogen is transported through closed pipeline systems, where the conditions for combustion are insufficient. However, operational requirements and safety considerations necessitate the venting of hydrogen after pipeline maintenance or emergency shutdowns, which imposes technical requirements on safe venting.

[0004] Generally, the venting system originates from the pressure regulating valve (or flow restrictor) near the high-pressure pipeline, and diffuses after being discharged from the vent riser through the venting pipeline, or is ignited and burned through a venting flare. During hydrogen release, due to its rapid combustion speed and wide explosion range, it faces problems such as a large total amount of medium participating in combustion after accidental ignition, accelerated combustion within the venting pipeline (semi-confined area), and backfire at the end of the venting process. The obvious consequences are increased internal pressure in the venting pipeline and accidental combustion within the venting pipeline, which imposes design requirements on the safety of the venting pipeline system.

[0005] However, some current technologies employ active protection methods to prevent accidental ignition, backfire, and detonation within the venting pipeline, overcoming these issues by increasing design redundancy. But given the relatively limited experience in constructing long-distance hydrogen pipelines, it is also necessary to conduct deflagration and backfire testing analysis of hydrogen venting systems from an experimental perspective, providing experimental test data to support the safety and optimization design of venting systems, thereby promoting further development of industry technology. Summary of the Invention

[0006] The purpose of this invention is to address the aforementioned technical problems by providing a system and method for testing the deflagration and backfire of a hydrogen pipeline venting system. This system can simulate hazardous scenarios such as spontaneous combustion, deflagration evolution, and backfire during actual hydrogen pipeline venting processes, supporting optimized implementation of engineering design and construction.

[0007] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0008] The first aspect of the present invention provides a deflagration and flashback testing system for a hydrogen pipeline venting system, including a premixing and concentration adjustment system, an adjustable venting system, a along-the-pipe temperature and pressure detection system, and a visual flashback detection system;

[0009] The premixing and concentration adjustment system is located inside the venting pipe, the adjustable venting system is located at the beginning of the venting pipe, the friction temperature and pressure detection system is located on the venting pipe, and the visual tempering detection system is located at the end of the venting pipe.

[0010] In one embodiment, the premixing and concentration regulation system includes a venting pipeline, a premixing flow transmitter, a premixing shut-off valve, a micro-leakage orifice plate, a sampling valve at the front end of the venting pipeline, a sampling valve in the middle section of the venting pipeline, and a sampling valve at the end of the venting pipeline. The venting pipeline is installed inside the venting pipeline, with one end of the venting pipeline connected to the upstream hydrogen storage device and the other end connected to the venting riser.

[0011] The venting pipeline includes the front venting pipeline, the middle venting pipeline, and the rear venting pipeline;

[0012] The premixed flow transmitter, premixed shut-off valve, micro-leakage orifice plate, and sampling valve at the front of the vent pipe are installed sequentially on the front vent pipe in the direction of airflow; the sampling valve in the middle of the vent pipe is installed on the middle vent pipe; and the sampling valve at the end of the vent pipe is installed on the rear vent pipe.

[0013] Specifically, the premixing and concentration regulation system mainly utilizes hydrogen introduced from the upstream hydrogen storage device to simulate a hydrogen-air mixed environment inside the venting pipeline, and provides a sampling interface to measure the mixing uniformity and concentration. It can also test the dilution and suction effect of the mixed medium by the naturally flowing air at the end, and realize functions such as supporting the testing of the concentration distribution of the medium inside the venting pipeline after upstream micro-leakage and the filling of premixed medium required for the deflagration experiment of the venting pipeline.

[0014] In one embodiment, the adjustable venting system includes an adjustable venting pipe, a venting flow transmitter, and a venting regulating valve. One end of the adjustable venting pipe is connected to an upstream hydrogen storage device, and the other end of the adjustable venting pipe is connected to a venting pipe behind the micro-leakage orifice plate. The venting flow transmitter and the venting regulating valve are mounted on the adjustable venting pipe.

[0015] Specifically, the adjustable venting system enables control of different venting flows, providing a hydrogen source for spontaneous combustion tests, deflagration tests, and backfire tests of the venting pipeline.

[0016] In one embodiment, the adjustable venting system includes a removable conduit.

[0017] Specifically, detachable pipelines mainly simulate and test the pressure development and accumulation state after a deflagration occurs in the initial section of the pipeline by setting detachable and replaceable pipe joints, pipes of different diameters, bends of different directions, flame arresters, etc.

[0018] In one embodiment, the friction-line temperature and pressure detection system is distributed, and the friction-line temperature and pressure detection system includes a front-end pressure transmitter, a front-end temperature transmitter, a middle-end pressure transmitter, a middle-end temperature transmitter, a rear-end pressure transmitter, a rear-end temperature transmitter, and an active spark generator. The front-end pressure transmitter, the front-end temperature transmitter, and the active spark generator are installed on the front-end vent pipe, the middle-end pressure transmitter and the middle-end temperature transmitter are installed on the middle-end vent pipe, and the rear-end pressure transmitter and the rear-end temperature transmitter are installed on the rear-end vent pipe.

[0019] Specifically, the pipeline temperature and pressure monitoring system mainly uses pressure transmitters and temperature transmitters installed at multiple points to detect the process of spontaneous combustion, deflagration, and deflagration development in the pipeline system during the release of hydrogen / hydrogen-blended natural gas. It also includes an active spark generator installed at the beginning of the venting pipeline. In addition, it also provides temperature and pressure monitoring functions for the pipeline end section during backfire testing.

[0020] In one embodiment, the visual tempering detection system includes a detachable transparent pipe, a pressure transmitter, a temperature transmitter, and a matching flame extension recording system; the detachable transparent pipe is detachably connected to the downstream vent pipe, and the pressure transmitter and temperature transmitter are mounted on the detachable transparent pipe.

[0021] Specifically, the visual flashback detection system is used to detect flashback combustion in the venting pipeline at the end of the venting process (when the venting flow rate decreases).

[0022] A second aspect of the present invention provides a method for testing the deflagration and flashback of a hydrogen pipeline venting system, which employs the aforementioned testing system for the deflagration and flashback of a hydrogen pipeline venting system and includes the following steps:

[0023] S1. Simulating the mixing of combustible media and air in the venting pipeline system under normal operating conditions of a hydrogen pipeline, when the venting valve experiences a minor leak: Open the premixed shut-off valve and the minor leak orifice plate, and keep the sampling valves at the front, middle, and end of the venting pipeline closed. The channel area of ​​the minor leak orifice plate is preferably 0.2 mm², and the orifice diameter can be changed according to actual needs. Preferably, samples are taken from the sampling valves at the front, middle, and end of the venting pipeline after opening and then sealing at a frequency of 2 hours / time. The concentration of the gas sampled at different points is analyzed to evaluate the concentration change and distribution patterns of the medium in the venting pipeline under the coupled effect of upstream minor leak and downstream airflow at the tail of the venting riser, providing experimental simulation data for the safe design, maintenance, and operation of the hydrogen pipeline venting system.

[0024] S2. Simulating Overpressure Distribution After Accidental Ignition in the Vent Pipeline: First, assemble the detachable pipeline and fittings. Multiple test pipeline models can be set up in the form of pure straight pipe, straight pipe + bend, etc. Following the operation method of step S1, fill the vent pipeline with leaked hydrogen. The concentration distribution after filling can be controlled according to actual needs to test the impact of the filling concentration on the overpressure after accidental ignition. Turn on the active spark generator to ignite the mixed medium in the front vent pipeline. Real-time pressure and temperature change data at different points in the vent pipeline are extracted through front pressure transmitter, front temperature transmitter, middle pressure transmitter, middle temperature transmitter, rear pressure transmitter, rear temperature transmitter, pressure transmitter, and temperature transmitter to analyze the pressure and temperature peaks of the vent pipeline under different operating conditions, providing support for the reasonable selection of the design pressure and design temperature of the vent pipeline.

[0025] S3. Simulate spontaneous combustion in a venting pipeline: Close the premixed shut-off valve and micro-leakage orifice plate; set parameters such as pressure and venting flow rate of the hydrogen storage device; replace the medium in the hydrogen storage device with hydrogen-blended natural gas through component blending; open the venting flow transmitter and venting regulating valve; monitor the test parameters of the upstream pressure transmitter, upstream temperature transmitter, mid-stage pressure transmitter, mid-stage temperature transmitter, downstream pressure transmitter, and downstream temperature transmitter in real time; simulate and analyze the scenario of spontaneous combustion in the venting pipeline; and form an evaluation law on the influence of hydrogen storage pressure, venting flow rate, and venting medium composition on spontaneous combustion in venting.

[0026] S4. Simulate the backfire effect after accidental ignition of the venting pipeline: First, the venting pipeline is purged with nitrogen. After the air content is below 2%, the venting regulating valve is opened to release the hydrogen in the hydrogen storage device without spontaneous combustion. Then, the discharge medium at the tail end of the venting riser is ignited using an electronic ignition system. After ignition, the opening of the venting regulating valve is manually reduced to simulate the backfire phenomenon caused by the reduction of the venting medium flow rate.

[0027] Specifically, this scheme can simulate and test key safety issues of hydrogen and hydrogen-blended natural gas venting systems, reveal the deflagration development pattern after accidental ignition under upstream micro-leakage, and obtain the peak deflagration overpressure under the influence of premixed concentration and flow channel coupling in the venting system. It can also reveal the influencing factors of spontaneous combustion and flashback in venting pipelines, and characterize the consequences of spontaneous combustion and flashback. This system and method can comprehensively support the safe design, operation, and maintenance of hydrogen and hydrogen-blended natural gas pipeline venting systems.

[0028] In one implementation, in step S1, the premixed shut-off valve is closed, and the same detection method is used to simulate and evaluate the distribution of the medium in the venting pipeline when the venting shut-off valve (characterized by the premixed shut-off valve) has potential internal leakage.

[0029] In one implementation, in step S4, the venting regulating valve is closed at different speeds according to the test requirements. The backfire effect at the end of the venting pipeline is observed and recorded using a detachable transparent pipe, pressure transmitter, temperature transmitter, and a matching flame spread recording system. Key parameters such as backfire length and overpressure value caused by backfire are recorded. This provides support for evaluating the design pressure of the venting pipeline, assessing the necessity of setting up a flame arrester, and also for safely stopping hydrogen venting.

[0030] This study investigates and analyzes the probability of deflagration, deflagration pressurization, backfire pressurization, and backfire impact range during hydrogen venting. It simulates the hydrogen-air premixed state inside the venting pipeline caused by internal leakage of the hydrogen valve using a premixing and concentration adjustment system. An adjustable venting system simulates the spontaneous combustion of hydrogen at different venting rates, providing key information such as critical pressure, critical concentration, and critical venting rate. The adjustable venting system also tests the impact of different pipe diameters and fitting configurations on the pressurization during deflagration. A temperature and pressure monitoring system along the pipeline is used to test the spontaneous combustion situation inside the venting pipeline, as well as the impact of different pipe diameters and fitting structures on deflagration overpressure, providing optimization schemes such as optimal pipe diameter ratios and fitting arrangements. It can also evaluate the maximum overpressure value of the venting system to support venting system selection. Finally, a visualized backfire detection system is established to test the scale of backfire after ignition and combustion, providing mitigation strategies.

[0031] The beneficial effects of this invention are as follows:

[0032] This invention, based on the operational characteristics of hydrogen pipeline venting systems, comprehensively considers the unique challenges faced by hydrogen (hydrogen-blended natural gas), including micro-leakage assessment, deflagration effects, spontaneous combustion of the vented medium, and backfire of the vented medium. It establishes a comprehensive testing system and method for simulation evaluation, providing a wide range of testing capabilities. Specifically:

[0033] (1) Scientific setup: This system addresses the special problems faced by hydrogen (hydrogen-blended natural gas) such as micro-leakage evaluation, deflagration impact, spontaneous combustion of vented medium, and vented medium backfire. It is equipped with a premixing and concentration adjustment system, an adjustable venting system, an adjustable venting system, a process temperature and pressure detection system, and a visual backfire detection system. By setting up a premixing and concentration adjustment system, the system simulates the hydrogen-air premixed state inside the venting pipeline caused by internal leakage of the hydrogen valve. By setting up an adjustable venting system, it simulates the spontaneous combustion state of hydrogen at different venting rates, providing key information such as critical pressure, critical concentration, and critical venting rate for spontaneous combustion. The adjustable venting system also tests the impact of different pipe diameters and fitting arrangements on the pressure rise during the deflagration process. By setting up a temperature and pressure detection system along the pipeline, the system tests the spontaneous combustion situation inside the venting pipeline and the impact of different pipe diameters and fitting structures on the deflagration overpressure, providing optimization schemes such as optimal pipe diameter ratios and optimal fitting arrangements. It can also evaluate the maximum overpressure value of the venting system to support the selection of the venting system. A visualized flashback detection system is established to test the flashback scale after ignition and combustion, providing mitigation strategies. This comprehensive approach effectively supports the safe design, operation, and maintenance of hydrogen pipeline venting systems, overcoming the shortcomings of existing numerical simulation analyses.

[0034] (2) Excellent economic potential: This invention addresses the key technical problems of current hydrogen venting systems. Through testing and analysis of key issues, it supports the optimization of venting system configuration and guides the operation and maintenance testing cycle of venting systems. For example, the self-ignition simulation test can support the necessity of replacement before venting, and the backfire simulation test can support the evaluation of the necessity of setting flame arresters in venting systems. This avoids the problem of using the same design method for different operating conditions and avoids over-design and construction of venting systems in some low-pressure pipeline projects.

[0035] (3) Promoting technological development: At present, my country has not yet carried out large-scale, long-distance high-pressure hydrogen pipeline operation. The scheme proposed in this system has played an important role in engineering guidance and reference. The proposed technical evaluation points such as premixed concentration distribution evaluation, deflagration evaluation, spontaneous combustion evaluation and backfire evaluation can directly provide key parameters for the safety design of venting pipelines, thus promoting the development of technical concepts and technological progress in this field. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of the present invention;

[0038] Figure reference numerals: 1-Premixed flow transmitter, 2-Premixed shut-off valve, 3-Micro-leakage orifice plate, 4-Sampling valve at the front end of the vent pipe, 5-Sampling valve at the middle end of the vent pipe, 6-Sampling valve at the end of the vent pipe;

[0039] 11-Vent flow transmitter; 12-Relief regulating valve;

[0040] 31 - Removable piping;

[0041] 41-Pre-stage pressure transmitter, 42-Pre-stage temperature transmitter, 43-Intermediate pressure transmitter, 44-Intermediate temperature transmitter, 45-Rear pressure transmitter, 46-Rear temperature transmitter, 47-Active spark generator; 51-Removable transparent pipe, 52-Pressure transmitter, 53-Temperature transmitter. Detailed Implementation

[0042] To make the technical problems, technical solutions, and technical effects of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Example 1

[0044] This embodiment provides a deflagration and flashback testing system for a hydrogen pipeline venting system, including a premixing and concentration adjustment system, an adjustable venting system, a along-the-pipe temperature and pressure detection system, and a visual flashback detection system;

[0045] The premixing and concentration adjustment system is located inside the venting pipe, the adjustable venting system is located at the beginning of the venting pipe, the friction temperature and pressure detection system is located on the venting pipe, and the visual tempering detection system is located at the end of the venting pipe.

[0046] The premixing and concentration regulation system includes a venting pipeline, a premixing flow transmitter 1, a premixing shut-off valve 2, a micro-leakage orifice plate 3, a sampling valve 4 at the front end of the venting pipeline, a sampling valve 5 at the middle end of the venting pipeline, and a sampling valve 6 at the end of the venting pipeline. The venting pipeline is located within the venting pipeline, with one end connected to the upstream hydrogen storage unit and the other end connected to the venting riser. The venting pipeline includes a front venting pipeline, a middle venting pipeline, and a rear venting pipeline. The premixing flow transmitter 1, the premixing shut-off valve 2, the micro-leakage orifice plate 3, and the sampling valve 4 at the front end of the venting pipeline are arranged sequentially on the front venting pipeline according to the airflow direction. The sampling valve 5 at the middle end of the venting pipeline is located on the middle venting pipeline, and the sampling valve 6 at the end of the venting pipeline is located on the rear venting pipeline.

[0047] Specifically, the premixing and concentration regulation system mainly utilizes hydrogen introduced from the upstream hydrogen storage device to simulate a hydrogen-air mixed environment inside the venting pipeline, and provides a sampling interface to measure the mixing uniformity and concentration. It can also test the dilution and suction effect of the mixed medium by the naturally flowing air at the end, and realize functions such as supporting the testing of the concentration distribution of the medium inside the venting pipeline after upstream micro-leakage and the filling of premixed medium required for the deflagration experiment of the venting pipeline.

[0048] The purpose of the premixing and concentration regulation system is as follows: During normal operation of the pipeline system, the pipeline system and the venting system are usually isolated by safety valves, emergency shut-off valves, and venting regulating valves. However, due to the small molecular weight of hydrogen, internal leakage of valves is prone to occur, resulting in the accumulation of leaked hydrogen in the venting pipeline. To address this, this solution includes a premixing and concentration regulation system. This system introduces hydrogen from the upstream hydrogen cylinder to simulate a hydrogen-air mixture environment inside the venting pipeline. It also provides a sampling interface to measure the mixing uniformity and concentration. Furthermore, it can test the dilution and absorption effect of the mixed medium by the naturally flowing air at the end. This system supports functions such as testing the concentration distribution of the medium inside the venting pipeline after an upstream micro-leakage and filling the venting pipeline with premixed medium for deflagration experiments.

[0049] The adjustable venting system includes an adjustable venting pipe, a venting flow transmitter 11, and a venting regulating valve 12. One end of the adjustable venting pipe is connected to the upstream hydrogen storage device, and the other end of the adjustable venting pipe is connected to the venting pipe behind the micro-leakage orifice plate 3. The venting flow transmitter 11 and the venting regulating valve 12 are installed on the adjustable venting pipe.

[0050] Specifically, the adjustable venting system enables control of different venting flows, providing a hydrogen source for spontaneous combustion tests, deflagration tests, and backfire tests of the venting pipeline.

[0051] The adjustable venting system includes a detachable pipeline 31. The detachable pipeline mainly simulates and tests the pressure development and accumulation state after a deflagration occurs in the initial section of the pipeline by setting detachable and replaceable pipe joints, pipes of different diameters, bends of different directions, flame arresters, etc.

[0052] The design purpose of the detachable pipeline 31 is as follows: Due to the strong spontaneous combustion tendency of hydrogen, the venting pipeline system may also experience deflagration in a semi-enclosed space due to the presence of explosive environments or ignition sources. In addition to causing the venting riser to accidentally form a venting flare, the shock wave generated by the deflagration will cause the internal pressure of the venting pipeline system to rise instantaneously. Different venting pipe diameters and venting pipeline layouts all have an impact on the pressure rise. It is difficult to quantitatively reveal the pressure rise scale through conventional simulation analysis methods. Therefore, this invention sets up an adjustable venting system to test the impact of different pipe diameter specifications and pipe fitting arrangements on the pressure rise during the deflagration process. By setting up a temperature and pressure detection system along the pipeline, the spontaneous combustion situation inside the venting pipeline can be tested. It can also test the impact of different pipe diameters and pipe fitting structures on the deflagration overpressure. It can provide optimization schemes such as optimal pipe diameter ratios and optimal pipe fitting layouts, and can evaluate the maximum overpressure value of the venting system to support the selection of the venting system.

[0053] The temperature and pressure monitoring system along the pipeline is distributed and includes a front-end pressure transmitter 41, a front-end temperature transmitter 42, a middle-end pressure transmitter 43, a middle-end temperature transmitter 44, a rear-end pressure transmitter 45, a rear-end temperature transmitter 46, and an active spark generator 47. The front-end pressure transmitter 41, the front-end temperature transmitter 42, and the active spark generator 47 are installed on the front-end venting pipeline, the middle-end pressure transmitter 43 and the middle-end temperature transmitter 44 are installed on the middle-end venting pipeline, and the rear-end pressure transmitter 45 and the rear-end temperature transmitter 46 are installed on the rear-end venting pipeline.

[0054] Specifically, the pipeline temperature and pressure detection system mainly uses pressure transmitters and temperature transmitters set at multiple points to detect the process of spontaneous combustion, deflagration, and deflagration development in the pipeline system during the release of hydrogen / hydrogen-blended natural gas. It also includes an active spark generating device 47 set at the beginning of the venting pipeline. In addition, it also provides the function of detecting the temperature and pressure of the pipeline end section during the backfire test.

[0055] The visual tempering detection system includes a detachable transparent pipe 51, a pressure transmitter 52, a temperature transmitter 53, and a matching flame extension recording system; the detachable transparent pipe 51 is detachably connected to the downstream vent pipe, and the pressure transmitter 52 and temperature transmitter 53 are installed on the detachable transparent pipe 51.

[0056] Specifically, the visual flashback detection system is used to detect flashback combustion in the venting pipeline when the discharge flow rate decreases at the end of the venting stage.

[0057] The purpose of the visual flashback detection system is as follows: Due to the significant decrease in flow rate at the end of the venting process, and the rapid combustion rate of hydrogen, if the gas is accidentally ignited or vented using a torch, flashback may occur at the end of the venting process due to the reduced flow rate. This could lead to combustion inside the venting pipeline and pressure changes. Therefore, this invention establishes a visual flashback detection system to test the scale of flashback after ignition and combustion, providing mitigation strategies.

[0058] Example 2

[0059] This embodiment provides a method for testing deflagration and backfire in a hydrogen pipeline venting system, including the following steps:

[0060] S1. Simulating the normal operation of a hydrogen pipeline, the mixing of combustible media and air in the venting pipeline system during a minor leak: Open the premixed shut-off valve 2 and the minor leak orifice plate 3, while keeping the sampling valve 4 at the front end of the venting pipeline, the sampling valve 5 in the middle section of the venting pipeline, and the sampling valve 6 at the end of the venting pipeline closed. The channel area of ​​the minor leak orifice plate 3 is preferably 0.2 mm², and the orifice diameter can be changed according to actual needs. Preferably, the sampling valve 4 at the front end of the venting pipeline and the sampling valve 5 in the middle section of the venting pipeline are sampled at a frequency of 2 hours / time. After the sampling valve 6 at the end of the venting pipeline is opened, it is closed to take samples and test the concentration of the medium at different sampling points. This is to evaluate the concentration change and distribution of the medium in the venting pipeline under the coupled effect of upstream micro-leakage and air flow at the tail end of the downstream venting riser, and to provide experimental simulation data for the safe design, maintenance and operation of the hydrogen pipeline venting system. Alternatively, the premixed shut-off valve 2 can be closed, and the same detection method can be used to simulate and evaluate the medium distribution in the venting pipeline when there is potential internal leakage of the venting shut-off valve (characterized by the premixed shut-off valve 2).

[0061] S2. Simulating the overpressure distribution after accidental ignition of the venting pipeline: First, assemble the pipes and fittings of the detachable pipeline 31. Multiple test pipeline models can be set up in the form of pure straight pipe, straight pipe + bend pipe, etc. Following the operation method of step S1, fill the venting pipeline with leaked hydrogen. The concentration distribution after filling can be controlled according to actual needs to test the effect of filling concentration on overpressure after accidental ignition. Turn on the active spark generating device 47 to ignite the mixed medium in the front venting pipeline. Real-time pressure and temperature change data at different points in the venting pipeline are extracted through the front pressure transmitter 41, front temperature transmitter 42, middle pressure transmitter 43, middle temperature transmitter 44, rear pressure transmitter 45, rear temperature transmitter 46, pressure transmitter 52, and temperature transmitter 53 to analyze the pressure and temperature peaks of the venting pipeline under different working conditions, providing support for the reasonable selection of the design pressure and design temperature of the venting pipeline.

[0062] S3. Simulate spontaneous combustion in a venting pipeline: Close the premixed shut-off valve 2 and the micro-leakage orifice plate 3; set parameters such as the pressure and venting flow rate of the hydrogen storage device, and replace the medium in the hydrogen storage device with hydrogen-blended natural gas through component blending; open the venting flow transmitter 11 and the venting regulating valve 12, and monitor the test parameters of the upstream pressure transmitter 41, the upstream temperature transmitter 42, the mid-stage pressure transmitter 43, the mid-stage temperature transmitter 44, the downstream pressure transmitter 45, and the downstream temperature transmitter 46 in real time, simulate and analyze the scenario of spontaneous combustion in the venting pipeline, and form an evaluation law on the influence of hydrogen storage pressure, venting flow rate, and venting medium composition on spontaneous combustion in venting.

[0063] S4. Simulating the impact of backfire after accidental ignition in the venting pipeline: First, the venting pipeline is purged with nitrogen. After the air content is below 2%, the venting regulating valve 12 is opened to release hydrogen from the hydrogen storage device without spontaneous combustion. Then, the discharge medium at the tail end of the venting riser is ignited using an electronic ignition system. After ignition, the opening of the venting regulating valve 12 is manually reduced to simulate the backfire phenomenon caused by the reduction in the flow rate of the venting medium. Furthermore, according to the test requirements, the venting regulating valve 12 is closed at different speeds. The backfire impact at the end of the venting pipeline is observed and recorded using a detachable transparent pipe 51, pressure transmitter 52, temperature transmitter 53, and a matching flame extension recording system. Key parameters such as the backfire length and the overpressure value caused by the backfire are recorded. This provides support for evaluating the design pressure of the venting pipeline, assessing the necessity of setting up a flame arrester, and also provides support for safely stopping the hydrogen release.

[0064] Specifically, this scheme can simulate and test key safety issues of hydrogen and hydrogen-blended natural gas venting systems, reveal the deflagration development pattern after accidental ignition under upstream micro-leakage, and obtain the peak deflagration overpressure under the influence of premixed concentration and flow channel coupling in the venting system. It can also reveal the influencing factors of spontaneous combustion and flashback in venting pipelines, and characterize the consequences of spontaneous combustion and flashback. This system and method can comprehensively support the safe design, operation, and maintenance of hydrogen and hydrogen-blended natural gas pipeline venting systems.

Claims

1. A deflagration and flashback testing system for a hydrogen pipeline venting system, characterized in that, Includes a premixing and concentration adjustment system, an adjustable venting system, a flow-through temperature and pressure monitoring system, and a visual tempering detection system; The premixing and concentration adjustment system is located inside the venting pipe, the adjustable venting system is located at the beginning of the venting pipe, the friction temperature and pressure detection system is located on the venting pipe, and the visual tempering detection system is located at the end of the venting pipe.

2. The deflagration and flashback testing system for a hydrogen pipeline venting system according to claim 1, characterized in that, The premixing and concentration regulation system includes a venting pipeline, a premixing flow transmitter (1), a premixing shut-off valve (2), a micro-leakage orifice plate (3), a sampling valve at the front end of the venting pipeline (4), a sampling valve at the middle end of the venting pipeline (5), and a sampling valve at the end of the venting pipeline (6). The venting pipeline is installed inside the venting pipeline. One end of the venting pipeline is connected to the upstream hydrogen storage device, and the other end is connected to the venting riser. The venting pipeline includes a front venting pipeline, a middle venting pipeline, and a rear venting pipeline. The premixed flow transmitter (1), the premixed shut-off valve (2), the micro-leakage orifice plate (3), and the sampling valve (4) of the vent pipe are arranged sequentially on the front vent pipe in the direction of airflow; the sampling valve (5) of the middle vent pipe is arranged on the middle vent pipe, and the sampling valve (6) of the end vent pipe is arranged on the rear vent pipe.

3. The deflagration and flashback testing system for a hydrogen pipeline venting system according to claim 2, characterized in that, The adjustable venting system includes an adjustable venting pipe, a venting flow transmitter (11), and a venting regulating valve (12). One end of the adjustable venting pipe is connected to the upstream hydrogen storage device, and the other end of the adjustable venting pipe is connected to the venting pipe behind the micro-leakage orifice plate (3). The venting flow transmitter (11) and the venting regulating valve (12) are installed on the adjustable venting pipe.

4. The deflagration and flashback testing system for a hydrogen pipeline venting system according to claim 2, characterized in that, The adjustable venting system includes a detachable conduit (31).

5. The deflagration and flashback testing system for a hydrogen pipeline venting system according to claim 2, characterized in that, The friction-track temperature and pressure detection system is distributed and includes a front-end pressure transmitter (41), a front-end temperature transmitter (42), a middle-end pressure transmitter (43), a middle-end temperature transmitter (44), a rear-end pressure transmitter (45), a rear-end temperature transmitter (46), and an active spark generator (47). The front-end pressure transmitter (41), the front-end temperature transmitter (42), and the active spark generator (47) are installed on the front-end vent pipe, the middle-end pressure transmitter (43) and the middle-end temperature transmitter (44) are installed on the middle-end vent pipe, and the rear-end pressure transmitter (45) and the rear-end temperature transmitter (46) are installed on the rear-end vent pipe.

6. The deflagration and flashback testing system for a hydrogen pipeline venting system according to claim 2, characterized in that, The visual tempering detection system includes a detachable transparent pipe (51), a pressure transmitter (52), a temperature transmitter (53), and a matching flame extension recording system; the detachable transparent pipe (51) is detachably connected to the downstream vent pipe, and the pressure transmitter (52) and the temperature transmitter (53) are mounted on the detachable transparent pipe (51).

7. A method for testing deflagration and backfire in a hydrogen pipeline venting system, characterized in that, The deflagration and backfire testing system for a hydrogen pipeline venting system as described in any one of claims 1 to 6 is adopted.

8. The method for testing deflagration and backfire in a hydrogen pipeline venting system according to claim 7, characterized in that, Includes the following steps: S1. Simulate the mixing of combustible medium and air in the venting pipeline system when the venting valve is slightly leaking during normal operation of the hydrogen pipeline: Open the premixed shut-off valve (2) and the slightly leaking orifice plate (3), keep the sampling valve (4) at the front end of the venting pipeline, the sampling valve (5) at the middle end of the venting pipeline and the sampling valve (6) at the end of the venting pipeline closed, and perform closed sampling after opening the sampling valve (4) at the front end of the venting pipeline, the sampling valve (5) at the middle end of the venting pipeline and the sampling valve (6) at the end of the venting pipeline, and test the concentration of the medium sampled at different points to evaluate the concentration change and distribution law of the medium in the venting pipeline under the coupling effect of upstream slightly leaking and downstream air flow at the tail end of the venting riser, so as to provide experimental simulation data for the safe design, maintenance and operation of the hydrogen pipeline venting system; S2. Simulate the overpressure distribution after accidental ignition of the venting pipeline: First, assemble the pipes and fittings of the detachable pipeline (31) and set up multiple test pipeline models; according to the operation method of step S1, fill the venting pipeline with leaked hydrogen. The concentration distribution after filling can be controlled according to actual needs to test the effect of filling concentration on overpressure after accidental ignition. The active spark generator (47) is activated to ignite the mixed medium in the front venting pipeline. The pressure and temperature change data at different points in the venting pipeline are extracted in real time to analyze the pressure and temperature peaks of the venting pipeline under different working conditions, so as to provide support for the reasonable selection of the design pressure and design temperature of the venting pipeline. S3. Simulate spontaneous combustion of venting pipeline: Close the premixed shut-off valve (2) and micro-leakage orifice plate (3); set the parameters of the hydrogen storage device, and replace the medium in the hydrogen storage device with hydrogen-blended natural gas through component blending; open the venting flow transmitter (11) and the discharge regulating valve (12), and monitor the test parameters of the front pressure transmitter (41), front temperature transmitter (42), middle pressure transmitter (43), middle temperature transmitter (44), rear pressure transmitter (45), and rear temperature transmitter (46) in real time, simulate and analyze the scenario of spontaneous combustion in the venting pipeline, and form the evaluation law of the influence of hydrogen storage pressure, discharge flow, and discharge medium composition on spontaneous combustion of venting. S4. Simulate the backfire effect after accidental ignition of the venting pipeline: First, the venting pipeline is replaced with nitrogen. After the air content is lower than 2%, the venting regulating valve (12) is opened to release the hydrogen in the hydrogen storage device without spontaneous combustion. Then, the discharge medium at the tail of the venting riser is ignited using an electronic ignition system. After ignition, the opening of the venting regulating valve (12) is manually reduced to simulate the backfire phenomenon caused by the reduction of the venting medium flow rate.

9. The method for testing deflagration and backfire in a hydrogen pipeline venting system according to claim 8, characterized in that, In step S1, the premixed shut-off valve (2) is closed, and the same detection method is used to simulate and evaluate the distribution law of the medium in the venting pipeline when the venting shut-off valve has potential internal leakage.

10. The method for testing deflagration and backfire in a hydrogen pipeline venting system according to claim 8, characterized in that, In step S4, the venting regulating valve (12) is closed at different speeds according to the test requirements. The backfire effect at the end of the venting pipeline is observed and recorded by using a detachable transparent pipe (51), pressure transmitter (52), temperature transmitter (53) and a matching flame spread recording system. The backfire length and the overpressure value caused by the backfire are recorded. This provides support for evaluating the design pressure of the venting pipeline and assessing the necessity of setting up the flame arrester, as well as for safely stopping the hydrogen venting.

Images