Active and passive integrated protection method and system for hydrogen safety in limited space

Abstract

The invention relates to an active and passive integrated protection method and system for hydrogen safety in a confined space, and the protection method specifically comprises the steps: building an equal ratio test model and a simulation model of a hydrogen utilization system in the confined space, and carrying out the numerical simulation analysis; carrying out limited space hazard source identification, determining installation positions of a limited space hydrogen leakage collection device and a hydrogen concentration sensor, and formulating a hydrogen micro-leakage criterion combining a hydrogen concentration change rate, a hydrogen concentration break variable and a hydrogen concentration threshold value; and determining an arrangement scheme of a limited space exhaust system and an explosion pressure relief system. The protection system comprises an active protection device and a passive protection device. Compared with the prior art, the method has the advantages that the accuracy of the simulation model is verified, the simulation model is continuously optimized and adjusted until the accuracy meets the requirement, and the obtained result is more reliable and is more consistent with the actual situation. The hydrogen safety active and passive integrated protection device provided by the invention has early warning and protection functions, and comprehensively and efficiently realizes prevention and control of system hydrogen safety.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen refueling station safety, and in particular to a confined space hydrogen safety active and passive integrated protection method and system. Background Art

[0002] Building a new power system based on photovoltaic power generation and wind power generation has become a research hotspot. Among them, the hydrogen-electricity coupling system with hydrogen energy as the core is an important trend in the future.

[0003] However, compared with conventional energy sources such as methane and natural gas, hydrogen has lower ignition energy, greater diffusion coefficient, wider flammable range, etc., which makes it a huge safety hazard in production applications. In addition, most distributed integrated energy application systems use a composite, compact, and relatively closed container structure. If hydrogen leaks from hydrogen-related equipment in the container, compared with conventional hydrogen utilization systems such as hydrogen refueling stations and hydrogen production plants, the hydrogen in the container is more likely to accumulate to form a flammable cloud, increasing the risk of explosion accidents. In practical applications, the method of arranging hydrogen concentration sensors is often used to detect and locate hydrogen leaks, but the sensor response time is slow and the positioning is inaccurate, resulting in untimely warnings. In terms of hydrogen safety protection devices, isolation methods are generally adopted, but the container structure is complex and compact. If a partition wall is set up inside, on the one hand, the space utilization rate is reduced, and on the other hand, the consequences of the accident may be aggravated; there is also an exhaust system method to reduce the hydrogen concentration, but how to reasonably determine the layout of the exhaust system to quickly reduce the environmental hydrogen concentration is also a problem that needs to be solved.

[0004] Therefore, developing a security protection method and device for active and passive integrated protection of hydrogen safety in confined spaces is of great significance for accident prevention and resolution. Summary of the invention

[0005] The purpose of the present invention is to provide a confined space hydrogen safety active and passive integrated protection method and system in order to overcome the defects of the above-mentioned prior art. The confined space micro-leakage test is used to verify the accuracy of the computational fluid dynamics simulation model, and the simulation model is continuously optimized and adjusted until the accuracy meets the requirements. The simulation analysis is based on the optimized and corrected simulation model, and the results obtained are more reliable and more consistent with the actual situation.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a confined space hydrogen safety active and passive integrated protection method, comprising the following steps:

[0008] S1: Establish a proportional test model of the confined space hydrogen utilization system, carry out hydrogen leakage tests, and clarify the leakage characteristics and diffusion laws of hydrogen leakage in confined spaces in actual applications;

[0009] S2: Establish a simulation model of the confined space hydrogen utilization system, conduct numerical simulation analysis on the temporal and spatial evolution of hydrogen leakage and diffusion in the confined space, and use the geometric experimental model in S1 to measure the accuracy of the simulation model;

[0010] S3: Carry out identification of hazardous sources in confined spaces. Based on the numerical simulation analysis results in S2, determine the installation locations of hydrogen leakage collection devices and hydrogen concentration sensors in confined spaces, and formulate hydrogen micro-leakage criteria based on the hydrogen concentration change rate, hydrogen concentration mutation amount and hydrogen concentration threshold to determine and quickly locate hydrogen leakage in confined spaces.

[0011] S4: Combine the operating process of the confined space hydrogen utilization system and the data of the hydrogen concentration sensor in S3 to formulate hydrogen leakage safety protection measures and execution logic, and determine the layout plan of the confined space exhaust system;

[0012] According to the simulation analysis results of hydrogen explosion simulated by the simulation model in S2, the layout plan of the explosion relief system in the confined space is determined, so as to realize the active and passive integrated protection of hydrogen safety in the confined space.

[0013] Furthermore, in S1, according to the actual structure of the distributed hydrogen energy storage system, a 1:1 scale test model is constructed and produced using UG (Unigraphics NX) modeling software. The scale test model is a test representative object that is copied from the actual distributed hydrogen energy storage system structure and has all or part of the characteristics of the actual structure. Combined with actual working conditions, the model experiment is carried out.

[0014] Furthermore, in S2, the accuracy rate refers to the accuracy of the simulation model in simulating the spatiotemporal evolution of hydrogen in a confined space, and the accuracy includes the accuracy of simulating the spatial distribution of hydrogen in the confined space and the accuracy of simulating the concentration evolution of hydrogen at the same position.

[0015] Furthermore, in S2, FLACS fluid dynamics simulation software was used to analyze the spatiotemporal evolution of hydrogen leakage and diffusion in confined spaces, and the simulation analysis results were compared with the model test results in S1, that is, the hydrogen concentration measured by the hydrogen concentration sensor in the model test was compared with the simulation results of the hydrogen concentration at the monitoring point at the same position in the simulation analysis, in order to verify the accuracy of the simulation model.

[0016] Furthermore, the parameters of the simulation model are set according to actual working conditions, and the accuracy judgment standard of the simulation model is: if the accuracy of the hydrogen concentration at the simulation detection point is greater than or equal to 80%, then the simulation model can simulate the leakage and diffusion behavior of hydrogen in a confined space.

[0017] Further, in S3, the hydrogen leakage collection device includes a hydrogen leakage collection device and a hydrogen concentration sensor, the hydrogen leakage collection device is used to form a confined space to facilitate the accumulation of hydrogen; the hydrogen concentration sensor is used to detect the hydrogen concentration in the collection device;

[0018] The installation position of the hydrogen leakage collection device is based on the simulation analysis results and is installed at a point where hydrogen is likely to accumulate;

[0019] The arrangement principle of the hydrogen concentration sensor is: based on the results of fluid dynamics simulation, a fast-response hydrogen concentration sensor is arranged at a location where hydrogen is likely to accumulate;

[0020] Based on the results of hazard source identification, high-precision hydrogen concentration sensors are arranged near points where hydrogen leakage is likely to occur.

[0021] Furthermore, in S3, the hydrogen micro-leakage judgment criterion based on the hydrogen concentration change rate, hydrogen concentration mutation amount and hydrogen concentration threshold is specifically to combine the judgment of the hydrogen concentration sensor with the graded warning, the sensed hydrogen concentration and the alarm time, and determine the leakage location according to the position of the sensor that generates the warning signal.

[0022] Further, in S4, the protective measures include using sound and light alarms, system shutdown, opening and closing valves, and starting an exhaust system;

[0023] The execution logic is to formulate the security logic when hydrogen leakage occurs in different working conditions and different equipment according to the warning level of the hydrogen concentration sensor and the hydrogen leakage location;

[0024] Further, in S4, the layout principle of the exhaust system is: according to the simulation analysis results in S2, a ventilation grid and a forced exhaust device are set at the position where hydrogen is easy to gather in the confined space, and through the analysis of influencing factors, the influence of different exhaust positions on the gathering of combustible clouds after hydrogen leakage is analyzed to obtain an exhaust system layout plan that is not prone to the gathering of combustible clouds;

[0025] The layout principle of the explosion relief system is: according to the simulation analysis results of hydrogen explosion in confined space, pressure relief plates are set at locations with higher explosion pressure.

[0026] The present invention also provides a confined space hydrogen safety active and passive integrated protection system, including an active protection device and a passive protection device, wherein the active protection device includes an audible and visual alarm, a forced exhaust component and an emergency stop component;

[0027] The passive protection device is a ventilation grid;

[0028] The ventilation grid and the forced exhaust assembly are used to discharge hydrogen out of the system to reduce the hydrogen concentration in the system;

[0029] The sound and light alarm is used for hydrogen micro-leakage alarm;

[0030] The emergency stop assembly is used to send out a protection interlock signal when an emergency occurs, and quickly stop the production process, thereby preventing the accident from expanding and worsening.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] 1. The confined space micro-leakage test adopted in the present invention verifies the accuracy of the computational fluid dynamics simulation model, and continuously optimizes and adjusts the simulation model until the accuracy meets the requirements. The simulation analysis performed is based on the optimized and corrected simulation model, and the results obtained are more reliable and more consistent with the actual situation.

[0033] 2. The sensor arrangement scheme proposed in the present invention is to arrange fast-response hydrogen concentration sensors at locations where hydrogen is likely to accumulate to detect large leaks, and to arrange high-precision hydrogen concentration sensors near key risk points to monitor micro leaks. This not only achieves rapid early warning of hydrogen leaks, but also can more accurately determine the leakage points, greatly improving the safety of system operation.

[0034] 3. The hydrogen safety active and passive integrated protection system proposed in the present invention has both early warning and protection functions, and can comprehensively and efficiently realize the prevention and control of system hydrogen safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of a hydrogen safety active and passive integrated protection method for confined spaces;

[0036] Figure 2 This is a schematic diagram of the modeling structure of the hydrogen leakage test in Example 1;

[0037] Figure 3 It is a simulation schematic diagram of the simulation model of the confined space in Example 1;

[0038] Figure 4 This is a schematic diagram of the structure of the confined space hydrogen leakage collection device in Example 1;

[0039] Figure 5 is a curve diagram of the combined criterion for hydrogen micro-leakage in Example 1;

[0040] Figure 6 A schematic diagram of hydrogen leakage safety protection and execution logic of the electrolytic hydrogen production system in the charging condition in Example 1;

[0041] Figure 7 This is a schematic diagram of the arrangement model of the exhaust device in Example 1;

[0042] Figure 8 This is a schematic diagram of the hydrogen safety active and passive integrated protection system in Example 1.

[0043] Figure 4 Description of the mark in:

[0044] 1- Sealing cover, 2- Hydrogen concentration sensor. DETAILED DESCRIPTION

[0045] The specific implementation methods of the present invention are described in detail below through examples. These examples are implemented on the premise of the scheme described in the present invention, and provide detailed implementation methods and specific operating processes, but the protection scope of the present invention is not limited to the following examples.

[0046] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Any features such as component models, material names, connection structures, preparation methods, materials, structures or composition ratios not clearly described in this technical solution are deemed to be common technical features disclosed in the prior art.

[0047] Example 1

[0048] This embodiment provides a confined space hydrogen safety active and passive integrated protection method, such as Figure 1 As shown, the following steps are included:

[0049] S1: Establish a scale test model of the confined space hydrogen utilization system and conduct a hydrogen leakage test to clarify the leakage characteristics and diffusion laws of hydrogen leakage in confined spaces in actual applications. According to the actual structure of the distributed hydrogen energy storage system, a 1:1 scale test model is constructed and produced using UG (Unigraphics NX) modeling software. The scale test model is a test representative replicated from the actual distributed hydrogen energy storage system structure and has all or part of the characteristics of the actual structure. Carry out model experiments in combination with actual working conditions.

[0050] S2: Based on the actual engineering model, the CFD-FLACS hydrogen safety simulation software is used to establish a three-dimensional fluid dynamics model of hydrogen leakage and diffusion in confined space, such as Figure 3 As shown in the figure, the simulation parameters are set according to the actual working conditions, and the temporal and spatial evolution of hydrogen leakage and diffusion in the confined space is numerically simulated and analyzed.

[0051] In order to ensure that the simulation results can guide practical applications, it is necessary to measure the accuracy of the simulation model. The accuracy is the simulation model's simulation accuracy of the spatiotemporal evolution of hydrogen in a confined space. The specific process is: the simulation model is subjected to a model test with the proportional test model in S1, and the obtained results are compared to verify the accuracy of the simulation model. The accuracy includes the accuracy of simulating the spatial distribution of hydrogen in a confined space and the accuracy of simulating the concentration evolution of hydrogen at the same position. The accuracy judgment standard of the simulation model is: if the accuracy of the hydrogen concentration at the simulation detection point is greater than or equal to 80%, then the simulation model can simulate the leakage and diffusion behavior of hydrogen in a confined space.

[0052] S3: Figure 4 As shown, the confined space hazard source identification is carried out, and the installation positions of the hydrogen leakage collection device and the hydrogen concentration sensor are determined based on the spatiotemporal evolution law of hydrogen leakage diffusion in the confined space obtained in S2. The installation position of the hydrogen leakage collection device should be the point where hydrogen accumulation is likely to occur in the simulation analysis results; the installation angle of the hydrogen leakage collection device should be determined in combination with the spatiotemporal evolution law of hydrogen leakage diffusion, and it should be located at a position that is conducive to the detection of leaked hydrogen.

[0053] The layout principle of hydrogen concentration sensors is as follows: based on the results of fluid dynamics simulation in S2, fast-response hydrogen concentration sensors are arranged at locations where hydrogen is likely to accumulate to achieve global detection of large leaks; based on the results of hazard source identification, high-precision hydrogen concentration sensors are arranged near points where hydrogen leaks are likely to occur to achieve near-field detection of micro leaks. The key risk points obtained by hazard source identification are shown in Table 1.

[0054] Table 1 Hazard source identification results

[0055]

[0056]

[0057] At the same time, a combined hydrogen micro-leakage criterion of hydrogen concentration change rate, hydrogen concentration mutation amount and hydrogen concentration threshold is formulated, such as Figure 5 As shown in the figure, if the concentration change rate of hydrogen leakage at a certain moment suddenly increases or the hydrogen concentration monitoring value suddenly increases, or the hydrogen leakage exceeds a certain range, it means that hydrogen leakage or fault has occurred, and an alarm is required to repair and eliminate the fault. Therefore, hydrogen concentration sensors arranged near the hydrogen leakage risk point are used to determine and grade hydrogen leaks to avoid large leaks. At the same time, based on the hydrogen concentration sensed by the hydrogen concentration sensor and the hydrogen concentration alarm time, the hydrogen leakage location is initially realized.

[0058] S4: Based on the operating process of the confined space hydrogen utilization system and the data of the hydrogen concentration sensor in S3, hydrogen leakage safety protection measures and execution logic are proposed to determine the layout plan of the confined space exhaust system.

[0059] The security measures include multiple measures such as sound and light alarm, system emergency shutdown, valve switching and exhaust system startup, and the execution logic is as follows: according to the different hydrogen concentration warning levels and hydrogen leakage locations in S3, the security logic for hydrogen leakage in different working conditions and different equipment is formulated to achieve rapid protection against hydrogen leakage. The security logic includes a hierarchical warning and security measure startup plan, and different security measures are taken for alarms of different warning levels. For example: a small leak is a low-level alarm, which only shuts down a certain device and does not affect the operation of other devices and systems; if a large leak occurs, the alarm level is higher, and interlocking control measures will be taken between the corresponding devices, and forced ventilation, system shutdown and other measures will be taken when necessary.

[0060] Figure 6 What is demonstrated is the hydrogen leakage safety protection and execution logic of the electrolytic hydrogen production system in the charging condition. Specifically, when the hydrogen concentration sensor detects hydrogen leakage in the hydrogen production system, the information obtained by the hydrogen concentration sensor is transmitted to the station control system, and a first-level sound and light warning is issued to remind the staff to take necessary measures; if the leakage continues, it is determined whether to upgrade the warning level based on the leakage criteria, and the emergency shutdown system takes interlocking measures to force the shutdown of the equipment involved, and sends a fault signal to the station control system, and takes shutdown measures for the downstream hydrogen storage facilities, and then the staff conducts inspection and maintenance until the fault is resolved.

[0061] The layout principle of the exhaust system is as follows: according to the simulation analysis results in S2, ventilation grids and forced exhaust devices are set at the locations where hydrogen is easy to gather in the confined space. Since different exhaust layout schemes have different effects on the diffusion of hydrogen leakage, the influence of different exhaust positions on the gathering of combustible clouds after hydrogen leakage is analyzed through different exhaust layout schemes, and the exhaust system layout scheme where combustible clouds are not easy to gather is obtained. The exhaust system layout of the confined space hydrogen utilization system is as follows: Figure 7 shown.

[0062] According to the results of hydrogen explosion simulation analysis, the layout of the explosion pressure relief system is determined to mitigate the consequences of explosion accidents, thereby achieving active and passive integrated protection of hydrogen safety in confined spaces. The layout principle of the explosion pressure relief system is: according to the results of hydrogen explosion simulation analysis in confined spaces, pressure relief panels are set at locations with high explosion pressure.

[0063] Example 2

[0064] This embodiment provides a hydrogen safety active and passive integrated protection system, such as Figure 8As shown, it includes a passive protection device and an active protection device arranged according to the protection method in Example 1. The passive protection device is a ventilation grid, and the active protection device includes an audible and visual alarm, a forced exhaust assembly, and an emergency stop assembly. The ventilation grid and the forced exhaust assembly are used to discharge hydrogen out of the system to reduce the hydrogen concentration in the system; the audible and visual alarm is used to alarm for hydrogen micro-leakage; the emergency stop assembly is used to send a protection interlock signal when an emergency occurs, quickly stop the production process, and thus prevent the expansion and deterioration of the accident.

[0065] The integrated protection system can effectively realize rapid early warning and protection of hydrogen accidents in hydrogen-related systems such as distributed hydrogen energy storage power stations. At the same time, the early warning logic and protection scheme proposed by the present invention are also applicable to open spaces such as hydrogen refueling stations and other flammable gas and toxic gas leakage early warning fields, and have a wide range of application scenarios.

[0066] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A confined space hydrogen safety active and passive integrated protection method, characterized in that: The following steps are involved: S1: Establish a proportional test model of the confined space hydrogen utilization system, carry out hydrogen leakage tests, and clarify the leakage characteristics and diffusion laws of hydrogen leakage in confined spaces in actual applications; S2: Establish a simulation model of the confined space hydrogen utilization system, conduct numerical simulation analysis on the temporal and spatial evolution of hydrogen leakage and diffusion in the confined space, and use the geometric experimental model in S1 to measure the accuracy of the simulation model; S3: Carry out identification of hazardous sources in confined spaces. Based on the numerical simulation analysis results in S2, determine the installation locations of hydrogen leakage collection devices and hydrogen concentration sensors in confined spaces, and formulate hydrogen micro-leakage criteria based on the hydrogen concentration change rate, hydrogen concentration mutation amount and hydrogen concentration threshold to determine and quickly locate hydrogen leakage in confined spaces. S4: Based on the operating process of the confined space hydrogen utilization system and the data obtained by the hydrogen concentration sensor in S3, formulate hydrogen leakage safety protection measures and execution logic, and determine the layout plan of the confined space exhaust system; According to the simulation analysis results of hydrogen explosion simulated by the simulation model in S2, the layout plan of the explosion relief system in the confined space is determined, so as to realize the active and passive integrated protection of hydrogen safety in the confined space.

2. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1 is characterized in that: In S1, the specific process of establishing the geometric test model is: according to the actual distributed hydrogen energy storage system structure, a 1:1 geometric test model is constructed and produced using UG modeling software. The geometric test model is a test representative object that is replicated according to the actual distributed hydrogen energy storage system structure and has all or part of the characteristics of the actual structure.

3. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1 is characterized in that: In S2, the accuracy rate refers to the simulation accuracy of the simulation model on the spatiotemporal evolution of hydrogen in a confined space, and the accuracy includes the accuracy of simulating the spatial distribution of hydrogen in the confined space and the accuracy of simulating the concentration evolution of hydrogen at the same position.

4. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1 is characterized in that: In S2, FLACS fluid dynamics simulation software was used to analyze the spatiotemporal evolution of hydrogen leakage and diffusion in confined spaces, and the simulation analysis results were compared with the model test results in S1, that is, the hydrogen concentration measured by the hydrogen concentration sensor in the model test was compared with the simulation results of the hydrogen concentration at the monitoring point at the same position in the simulation analysis to verify the accuracy of the simulation model.

5. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 3 is characterized in that: The parameters of the simulation model are set according to actual working conditions. The accuracy judgment standard of the simulation model is: if the accuracy of hydrogen concentration at the simulation detection point is greater than or equal to 80%, the simulation model can simulate the leakage and diffusion behavior of hydrogen in a confined space.

6. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1, characterized in that: In S3, the hydrogen leakage collection device includes a sealing cover and a hydrogen concentration sensor, the hydrogen concentration sensor is placed inside the sealing cover, and an opening is provided at the bottom of the sealing cover to form a confined space for collecting the escaped hydrogen; The hydrogen concentration sensor is used to detect the hydrogen concentration in the sealing cover; The installation position of the hydrogen leakage collection device is based on the simulation analysis results and is installed at a point where hydrogen is likely to accumulate; The arrangement principle of the hydrogen concentration sensor is: based on the results of fluid dynamics simulation, a fast-response hydrogen concentration sensor is arranged at a location where hydrogen is likely to accumulate; Based on the results of hazard source identification, high-precision hydrogen concentration sensors are arranged near points where hydrogen leakage is likely to occur.

7. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1, characterized in that: In S3, the hydrogen micro-leakage judgment criterion based on the hydrogen concentration change rate, hydrogen concentration mutation amount and hydrogen concentration threshold is specifically to combine the judgment of the hydrogen concentration sensor with the graded warning, the sensed hydrogen concentration and the alarm time, and determine the leakage location according to the location of the sensor that generates the warning signal.

8. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1, characterized in that: In S4, the protective measures include using sound and light alarms, system shutdown, opening and closing valves, and starting the exhaust system; The execution logic is to formulate the security logic when hydrogen leakage occurs in different working conditions and different equipment according to the warning level of the hydrogen concentration sensor and the hydrogen leakage location.

9. The method for integrated active and passive protection of hydrogen safety in confined spaces according to claim 1, characterized in that: In S4, the layout principle of the exhaust system is as follows: according to the simulation analysis results in S2, ventilation grids and forced exhaust devices are set at locations where hydrogen is likely to accumulate in the confined space, and the influence of different exhaust positions on the accumulation of combustible clouds after hydrogen leakage is analyzed through influencing factor analysis, so as to obtain an exhaust system layout plan that is not prone to the accumulation of combustible clouds; The layout principle of the explosion relief system is: according to the simulation analysis results of hydrogen explosion in confined space, pressure relief plates are set at locations with higher explosion pressure.

10. A confined space hydrogen safety active and passive integrated protection system, characterized in that: The active protection device and the passive protection device arranged in any one of the protection methods of claims 1 to 9, wherein the active protection device comprises an audible and visual alarm, a forced exhaust component and an emergency stop component; The passive protection device is a ventilation grid; The ventilation grid and the forced exhaust assembly are used to discharge hydrogen out of the system to reduce the hydrogen concentration in the system; The sound and light alarm is used for hydrogen micro-leakage alarm; The emergency stop assembly is used to send out a protection interlock signal when an emergency occurs, and quickly stop the production process, thereby preventing the accident from expanding and worsening.

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