CN115899582A - Ventilation method and related device for leaked hydrogen-doped natural gas pipeline in comprehensive pipe gallery - Google Patents

Abstract

The application discloses a ventilation method and a related device for a leaked hydrogen-doped natural gas pipeline in a comprehensive pipe rack, wherein the method comprises the steps of obtaining a first alarm concentration and a second alarm concentration of a leakage alarm and the interval time of the first alarm concentration and the second alarm concentration; determining the diameter of a leakage hole according to the first alarm concentration, the second alarm concentration, the interval time and the operating pressure of the pipeline; calculating the leakage flow according to the diameter of the leakage hole and the hydrogen-loading ratio; according to the leakage flow, and the pipe gallery volume and the gas concentration of the pipe gallery, determining the ventilation frequency, and controlling the pipe gallery to ventilate according to the ventilation frequency. The application utilizes the different warning grade response interval time, pipeline operating pressure and the doping of gas concentration alarm to compare the ventilation frequency who confirms that the pipe gallery corresponds to ventilate according to ventilation frequency, make the concentration of the doping natural gas of leakage in the pipe gallery certainly reduce below the explosion limit under the condition of fastest reaction time, in order to ensure the safety of pipe gallery.

Description

Ventilation method and related devices after leakage of hydrogen-blended natural gas pipeline in comprehensive pipe gallery

Technical Field

The present application relates to the technical field of integrated pipe corridors, and in particular to a ventilation method and related devices after a hydrogen-blended natural gas pipeline leaks in an integrated pipe corridor.

Background Art

The transportation and application of hydrogen-blended gas pipelines is an important direction for the strategic development of the hydrogen energy industry. However, in the engineering application link, there are still problems such as the immaturity of hydrogen-blended technology and insufficient verification of safety. The most typical of these is the safety issue of hydrogen-blended natural gas pipelines entering municipal integrated pipeline corridors.

Compared with natural gas, hydrogen has significantly different physical and chemical properties, with smaller density, smaller ignition energy, larger diffusion coefficient and wider explosion limit. The current safety control technology related to gas pipeline corridors is designed for hydrogen-blended natural gas pipelines. GB 50838-2015 "Technical Specifications for Urban Integrated Pipeline Corridor Engineering" stipulates the normal ventilation and emergency ventilation times of hydrogen-blended natural gas pipeline cabins. However, when hydrogen-blended natural gas with different hydrogen blending ratios, different pipeline internal pressures, and different leakage hole sizes leaks into the integrated pipeline corridor, when the combustible gas detection probe detects the leak and starts the emergency ventilation, the existing ventilation strategy cannot ensure that the concentration of the leaked hydrogen-blended natural gas in the pipeline corridor must be reduced to below the explosion limit, and the safety of the pipeline corridor cannot be ensured.

Therefore the prior art still needs to be improved and enhanced.

Summary of the invention

The technical problem to be solved by the present application is to provide a ventilation method and related devices after leakage of a hydrogen-blended natural gas pipeline in an integrated pipeline gallery in view of the deficiencies in the prior art.

In order to solve the above technical problems, the first aspect of the embodiment of the present application provides a ventilation method for leakage of a hydrogen-blended natural gas pipeline in a pipe gallery, the method comprising:

Obtaining a first alarm concentration, a second alarm concentration, and an interval between the first alarm concentration and the second alarm concentration of a leakage alarm;

Determining the leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time, and the pipeline operating pressure of the hydrogen-blended natural gas pipeline;

Calculating the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio;

The ventilation frequency corresponding to the pipe gallery is determined according to the leakage flow rate, the pipe gallery volume and the gas concentration of the pipe gallery, and the pipe gallery is controlled to be ventilated according to the ventilation frequency.

The ventilation method for leakage of hydrogen-blended natural gas pipeline in the pipe gallery is characterized in that when two adjacent leakage alarms sound an alarm, the leakage alarm is the leakage alarm located on the downwind side of the ventilation in the pipe gallery.

The ventilation method for leakage of hydrogen-blended natural gas pipeline in the pipeline gallery, wherein the determining of the leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time and the pipeline operating pressure of the hydrogen-blended natural gas pipeline specifically comprises:

determining a concentration change value according to the first alarm concentration and the second alarm concentration;

The pipeline operating pressure of the hydrogen-blended natural gas pipeline is read, and the leakage hole diameter of the hydrogen-blended natural gas pipeline is calculated based on the corresponding relationship among the pipeline operating pressure, the concentration change value, the interval time and the leakage hole diameter, wherein the corresponding relationship is:

Among them, ΔC represents the concentration change value; Δt represents the interval time, d is the leakage hole diameter; P ₂ represents the pipeline operating pressure, K ₁ and K ₂ are known coefficients.

The ventilation method for leakage of hydrogen-doped natural gas pipeline in the pipeline gallery, wherein the leakage flow of the hydrogen-doped natural gas pipeline is calculated according to the leakage hole diameter and the hydrogen doping ratio, specifically comprising:

Read the absolute pipeline pressure, hydrogen blending ratio, pipeline wall thickness and natural gas temperature of hydrogen-blended natural gas pipeline;

The leakage hole area is calculated according to the leakage hole diameter, and the leakage hole coefficient is calculated according to the leakage hole diameter, hydrogen mixing ratio and pipeline wall thickness;

The leakage flow is calculated based on the leakage hole coefficient, leakage hole area, pipeline absolute pressure and natural gas temperature.

The ventilation method for leakage of hydrogen-blended natural gas pipeline in the pipeline gallery, wherein the calculation formula of the leakage hole coefficient is:

表示泄漏孔系数，d表示泄漏孔直径，l表示管道壁厚度，λ表示掺氢比，a,b,c为已知系数。in,

represents the leakage hole coefficient, d represents the leakage hole diameter, l represents the pipe wall thickness, λ represents the hydrogen mixing ratio, and a, b, c are known coefficients.

The ventilation method for leakage of hydrogen-blended natural gas pipeline in the pipeline gallery, wherein the calculation formula of the leakage flow is:

表示泄漏孔系数，P₂表示管道绝对压力，T₂表示掺氢天然气管道内的天然气温度，A_or表示泄漏孔面积，d表示泄漏孔直径，γ表示掺氢天然气比热比，R表示掺氢天然气的气体常数，ρ₃表示掺氢天然气环境状态下的气体密度。Where _Qleakage represents the leakage flow,

represents the leakage hole coefficient, _P2 represents the absolute pressure of the pipeline, _T2 represents the natural gas temperature in the hydrogen-blended natural gas pipeline, A _or represents the leakage hole area, d represents the leakage hole diameter, γ represents the specific heat ratio of the hydrogen-blended natural gas, R represents the gas constant of the hydrogen-blended natural gas, and _ρ3 represents the gas density of the hydrogen-blended natural gas under the environmental state.

The ventilation method for leakage of hydrogen-blended natural gas pipeline in the pipe gallery, wherein the determining of the ventilation frequency body corresponding to the pipe gallery according to the leakage flow rate, the pipe gallery volume and the gas concentration of the pipe gallery comprises:

Determine the ventilation volume corresponding to the pipe gallery according to the leakage flow and the gas concentration of the pipe gallery;

The ventilation frequency is determined according to the ventilation volume and the corridor volume of the corridor, wherein the calculation formula of the ventilation frequency is:

Among them, n represents the ventilation frequency, _Qventilation represents the ventilation volume, Vpipeline _gallery represents the volume of the pipeline gallery, and α>1 represents the amplification factor.

A second aspect of the embodiment of the present application provides a ventilation system for leakage of a hydrogen-blended natural gas pipeline in a pipe gallery, the system comprising:

An acquisition module, used for acquiring a first alarm concentration, a second alarm concentration, and an interval between the first alarm concentration and the second alarm concentration of the leakage alarm;

A determination module, configured to determine a leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time, and the pipeline operating pressure of the hydrogen-blended natural gas pipeline;

A calculation module, used for calculating the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio;

The control module is used to determine the ventilation frequency corresponding to the pipe gallery according to the leakage flow rate, the pipe gallery volume and the gas concentration of the pipe gallery, and control the pipe gallery to be ventilated according to the ventilation frequency.

A third aspect of an embodiment of the present application provides a computer-readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the ventilation method after leakage of a hydrogen-blended natural gas pipeline in an integrated pipeline corridor as described in any of the above.

A fourth aspect of the embodiments of the present application provides a terminal device, comprising: a processor, a memory, and a communication bus; the memory stores a computer-readable program that can be executed by the processor;

The communication bus realizes the connection and communication between the processor and the memory;

When the processor executes the computer-readable program, the steps in the ventilation method after leakage of the hydrogen-blended natural gas pipeline in the integrated pipeline gallery as described above are implemented.

Beneficial effects: Compared with the prior art, the present application provides a ventilation method and related devices after a hydrogen-blended natural gas pipeline leaks in an integrated pipe gallery, the method comprising obtaining the first alarm concentration, the second alarm concentration, and the interval time between the first alarm concentration and the second alarm concentration of the leakage alarm; determining the leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time, and the pipeline operating pressure of the hydrogen-blended natural gas pipeline; calculating the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio; determining the ventilation frequency corresponding to the pipe gallery according to the leakage flow, as well as the pipe gallery volume and gas concentration of the pipe gallery, and controlling the pipe gallery to be ventilated according to the ventilation frequency. The present application utilizes the response interval time of different alarm levels of the gas concentration alarm, the pipeline operating pressure, and the hydrogen blending ratio to determine the ventilation frequency corresponding to the pipe gallery, and ventilates according to the ventilation frequency, so that the concentration of the leaked hydrogen-blended natural gas in the pipe gallery is reduced to below the explosion limit under the fastest response time, so as to ensure the safety of the pipe gallery.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

FIG1 is a flow chart of a ventilation method after leakage of a hydrogen-blended natural gas pipeline in an integrated pipeline gallery provided in the present application.

FIG2 is a flowchart illustrating an example of a ventilation method after a hydrogen-blended natural gas pipeline leaks in an integrated pipeline corridor provided in the present application.

FIG3 is a structural principle diagram of the ventilation system after a hydrogen-blended natural gas pipeline leaks in the integrated pipeline corridor provided in the present application.

FIG4 is a schematic diagram of the structure of the terminal device provided in this application.

DETAILED DESCRIPTION

The present application provides a ventilation method and related devices after leakage of hydrogen-doped natural gas pipeline in an integrated pipe gallery. In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

It will be understood by those skilled in the art that, unless expressly stated, the singular forms "one", "said", and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. It should be understood that when we refer to an element as being "connected" or "coupled" to another element, it may be directly connected or coupled to the other element, or there may be an intermediate element. In addition, the "connection" or "coupling" used herein may include wireless connection or wireless coupling. The term "and/or" used herein includes all or any unit and all combinations of one or more associated listed items.

It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as here.

It should be understood that the sequence number and size of each step in this embodiment do not mean the order of execution. The execution order of each process is determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application.

After research, the inventors found that the transportation and application of hydrogen-blended gas pipelines is an important direction for the strategic development of the hydrogen energy industry. However, in the engineering application link, there are still problems such as the immaturity of hydrogen-blending technology and insufficient verification of safety. The most typical of these is the safety issue of hydrogen-blended natural gas pipelines entering municipal integrated pipeline corridors.

Compared with natural gas, hydrogen has significantly different physical and chemical properties, with smaller density, smaller ignition energy, larger diffusion coefficient and wider explosion limit. The current safety control technology related to gas pipeline corridors is designed for hydrogen-blended natural gas pipelines. GB 50838-2015 "Technical Specifications for Urban Integrated Pipeline Corridor Engineering" stipulates the normal ventilation and emergency ventilation times of hydrogen-blended natural gas pipeline cabins. However, when hydrogen-blended natural gas with different hydrogen blending ratios, different pipeline internal pressures, and different leakage hole sizes leaks into the integrated pipeline corridor, when the combustible gas detection probe detects the leak and starts the emergency ventilation, the existing ventilation strategy cannot ensure that the concentration of the leaked hydrogen-blended natural gas in the pipeline corridor must be reduced to below the explosion limit, and the safety of the pipeline corridor cannot be ensured.

In addition, the combustible gas detection probes currently used in pipe corridors can usually only detect the concentration of methane, which cannot correctly reflect the concentration of the combustible mixed gas. Therefore, it is necessary to redesign a new ventilation method based on the characteristics of hydrogen-blended natural gas and the different operating conditions of hydrogen-blended natural gas pipelines, and based on the leakage and diffusion characteristics of hydrogen-blended natural gas, to ensure that after an accident occurs, the combustible gas concentration in the pipe corridor can be quickly reduced to below the explosion limit, thereby improving the safe operation factor of the pipe corridor.

In order to solve the above problems, in an embodiment of the present application, the first alarm concentration, the second alarm concentration and the interval time between the first alarm concentration and the second alarm concentration of the leakage alarm are obtained; the leakage hole diameter of the hydrogen-blended natural gas pipeline is determined according to the first alarm concentration, the second alarm concentration, the interval time and the pipeline operating pressure of the hydrogen-blended natural gas pipeline; the leakage flow of the hydrogen-blended natural gas pipeline is calculated according to the leakage hole diameter and the hydrogen blending ratio; the ventilation frequency corresponding to the pipeline gallery is determined according to the leakage flow, as well as the gallery volume and gas concentration of the gallery, and the gallery is controlled to be ventilated according to the ventilation frequency. The present application uses the response interval time of different alarm levels of the gas concentration alarm, the pipeline operating pressure and the hydrogen blending ratio to determine the ventilation frequency corresponding to the gallery, and ventilates according to the ventilation frequency, so that the concentration of the leaked hydrogen-blended natural gas in the gallery is reduced to below the explosion limit under the fastest response time to ensure the safety of the gallery.

The application content is further explained below through the description of embodiments in conjunction with the accompanying drawings.

This embodiment provides a ventilation method for a hydrogen-blended natural gas pipeline in an integrated pipe gallery after leakage, as shown in FIG1 , the method comprising:

S10, obtaining a first alarm concentration, a second alarm concentration, and an interval between the first alarm concentration and the second alarm concentration of the leakage alarm.

Specifically, the first alarm concentration is the alarm concentration when the leak alarm sounds an alarm once, and the second alarm concentration is the alarm concentration when the leak alarm sounds an alarm again, wherein the first alarm concentration and the second alarm concentration are different, for example, the first alarm concentration is 1%, and the second alarm concentration is 3%. In addition, the first alarm concentration and the second alarm concentration can be the alarm concentrations of two consecutive alarms of the leak alarm, or the alarm concentrations of two discontinuous alarms, for example, the first alarm concentration is the alarm concentration of the first alarm of the leak alarm, and the second alarm concentration is the alarm concentration of the second alarm of the leak alarm, or the first alarm concentration is the alarm concentration of the first alarm of the leak alarm, and the second alarm concentration is the alarm concentration of the third alarm of the leak alarm, etc. The interval time refers to the time difference between the alarm time corresponding to the first alarm concentration and the alarm time corresponding to the second alarm concentration, for example, the alarm time of the first alarm concentration is 10 o'clock, and the alarm time of the second alarm concentration is 10.5 seconds, then the interval time is 5 seconds.

In one implementation, the leakage alarm sets several levels of alarm concentrations from small to large. When the detection concentration reaches the first level alarm concentration, the leakage alarm generates an alarm. When the detection concentration reaches the second level alarm concentration, the leakage alarm generates an alarm again, and the alarm time of each alarm is recorded. Thus, the first alarm concentration, the second alarm concentration, and the interval between the first alarm concentration and the second alarm concentration can be obtained by determining the alarm concentration according to the alarm level generated by the leakage alarm and determining the alarm interval based on the alarm time of the property alarm.

In one implementation, the leakage alarm is installed in the pipe gallery, and when two adjacent leakage alarms in the pipe gallery both generate alarms, the first alarm concentration and the second alarm concentration are for the leakage alarm located on the downwind side of the two leakage alarms. This is because the concentration of the leakage alarm located on the downwind side of the ventilation in the pipe gallery changes over time, and the accuracy of the ventilation frequency can be subsequently determined based on the first alarm concentration and the second alarm concentration. The leakage alarm may be a combustible gas detection probe, etc.

S20. Determine the leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time, and the pipeline operating pressure of the hydrogen-blended natural gas pipeline.

Specifically, the pipeline operating pressure is the pipeline pressure when the hydrogen-blended natural gas pipeline is operating normally, and the leakage hole diameter is used to reflect the leakage range of the natural gas pipeline. Among them, the gas concentration in the pipeline corridor is related to the leakage hole diameter of the natural gas pipeline and the pipeline operating pressure of the natural gas pipeline, and increases with the increase of the leakage hole diameter and the pipeline operating pressure. Based on this, in one implementation, the determination of the leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time and the pipeline operating pressure of the hydrogen-blended natural gas pipeline specifically includes:

S21, determining a concentration change value according to the first alarm concentration and the second alarm concentration;

S22, reading the pipeline operating pressure of the hydrogen-blended natural gas pipeline, and calculating the leakage hole diameter of the hydrogen-blended natural gas pipeline based on the corresponding relationship among the pipeline operating pressure, the concentration change value, the interval time and the leakage hole diameter, wherein the corresponding relationship is:

Among them, ΔC represents the concentration change value; Δt represents the interval time, d is the leakage hole diameter; P ₂ represents the pipeline operating pressure, K ₁ and K ₂ are known coefficients.

Specifically, the concentration change value is equal to the absolute value of the difference between the first alarm concentration and the second alarm concentration. For example, assuming that the first alarm concentration is less than the second alarm concentration, the concentration change value = the second alarm concentration - the first alarm concentration. Wherein, the concentration change value is a percentage, the unit of the interval time is seconds, the unit of the leakage hole diameter is millimeters, the unit of the pipeline operating pressure is megapascals MPa, _K1 and _K2 are known coefficients that can be determined by experiments or numerical simulations. In a typical implementation, _K1 can be 23× ^10-4 , _K2 can be 114× ^10-4 , and accordingly, the corresponding relationship is:

S30, calculating the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio.

Specifically, the hydrogen blending ratio is the ratio of hydrogen blended in the natural gas transmitted in the hydrogen blended natural gas pipeline, and hydrogen blended natural gas with different hydrogen blending ratios has different explosion limits. After obtaining the hydrogen blending ratio, the explosion limit of the natural gas transmitted in the hydrogen blended natural gas pipeline can be determined, wherein the calculation formula of the explosion limit can be:

Wherein, L is the explosion limit of the mixed gas, _Li is the explosion limit of each single component, and _Yi is the volume fraction of each single component gas. In addition, when L is the upper explosion limit, _Li is the upper explosion limit of a single component; conversely, when L is the lower explosion limit, _Li is the lower explosion limit of a single component. For example, the explosion limits of natural gas with various hydrogen blending ratios are shown in Table 1.

Table 1 Explosion limits of natural gas with different hydrogen blending ratios

Furthermore, after obtaining the hydrogen blending ratio, the molar mass M of the hydrogen-blended natural gas, in g/mol; the gas density ρ, in kg/m ³ ; the gas constant R, in J/(kg·K); the specific heat capacity at constant pressure Cp, in J/(kg·K); the specific heat capacity at constant volume Cv, in J/(kg·K); and the specific heat ratio γ can also be calculated according to the hydrogen blending ratio. The specific heat ratio is defined as the ratio of the specific heat capacity at constant pressure to the specific heat capacity at constant volume, and its expression can be:

In addition, it is worth noting that the molar mass M of hydrogen-doped natural gas, unit is g/mol; gas density ρ, unit is kg/m ³ ; gas constant R, unit is J/(kg·K); specific heat capacity at constant pressure Cp, unit is J/(kg·K); specific heat capacity at constant volume Cv, unit is J/(kg·K) can all be calculated using existing methods, which will not be described in detail here.

In one implementation, the calculating the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio specifically includes:

Read the absolute pipeline pressure, hydrogen blending ratio, pipeline wall thickness and natural gas temperature of hydrogen-blended natural gas pipeline;

The leakage hole area is calculated according to the leakage hole diameter, and the leakage hole coefficient is calculated according to the leakage hole diameter, hydrogen mixing ratio and pipeline wall thickness;

The leakage flow is calculated based on the leakage hole coefficient, leakage hole area, pipeline absolute pressure and natural gas temperature.

Specifically, the calculation formula of the leakage hole coefficient is:

表示泄漏孔系数，d表示泄漏孔直径，l表示管道壁厚度，λ表示掺氢比，a,b,c为已知系数，其中，a,b,c可以根据实际情况确定，在一个典型实现方式中，a＝7.27×10^-2，b＝1.96×10^-3，c＝7.15×10^-1，采用该系数可以提高最后计算得到的通风频率的准确性。in,

represents the leakage hole coefficient, d represents the leakage hole diameter, l represents the pipe wall thickness, λ represents the hydrogen mixing ratio, a, b, c are known coefficients, where a, b, c can be determined according to actual conditions. In a typical implementation, a＝7.27×10 ^-2 , b＝1.96×10 ^-3 , c＝7.15×10 ^-1 . The use of this coefficient can improve the accuracy of the ventilation frequency finally calculated.

After obtaining the leakage hole coefficient, the specific heat ratio γ, the gas constant R and the gas density can be determined according to the hydrogen doping ratio, and then the leakage flow rate can be calculated according to the specific heat ratio γ, the gas constant R, the gas density and the leakage hole coefficient, wherein the calculation formula of the leakage flow rate is:

表示泄漏孔系数，P₂表示管道绝对压力，T₂表示掺氢天然气管道内的天然气温度，A_or表示泄漏孔面积，d表示泄漏孔直径，γ表示比热比，R表示掺氢天然气管道内的气体常数，ρ₃表示掺氢天然气管道内的气体密度。Where _Qleakage represents the leakage flow,

represents the leakage hole coefficient, _P2 represents the pipeline absolute pressure, _T2 represents the natural gas temperature in the hydrogen-blended natural gas pipeline, A _or represents the leakage hole area, d represents the leakage hole diameter, γ represents the specific heat ratio, R represents the gas constant in the hydrogen-blended natural gas pipeline, and _ρ3 represents the gas density in the hydrogen-blended natural gas pipeline.

S40, determining a ventilation frequency corresponding to the pipe gallery according to the leakage flow rate, the pipe gallery volume and the gas concentration of the pipe gallery, and controlling the pipe gallery to be ventilated according to the ventilation frequency.

Specifically, the ventilation frequency refers to the number of ventilations per unit time. In this embodiment, the unit time is 1 hour, that is, the ventilation frequency refers to the number of ventilations per hour. After the ventilation frequency is obtained, the pipe gallery is controlled to be ventilated according to the ventilation frequency to ensure the safety of the pipe gallery.

In an implementation of this embodiment, determining the ventilation frequency body corresponding to the pipe gallery according to the leakage flow rate, the pipe gallery volume and the gas concentration of the pipe gallery includes:

Determine the ventilation volume corresponding to the pipe gallery according to the leakage flow and the gas concentration of the pipe gallery;

The ventilation frequency is determined according to the ventilation volume and the tunnel volume of the tunnel.

Specifically, after a gas pipeline leaks, the gas concentration in the corridor depends on the leakage volume and the ventilation volume, where the ventilation volume depends on the ventilation frequency and the corridor volume. Based on this, the gas concentration in the corridor can be equal to the ratio of the leakage flow rate to the total amount of gas in the corridor, where the total amount of gas is equal to the sum of the leakage flow rate and the ventilation volume. In other words, the gas concentration in the corridor = leakage flow rate/(leakage flow rate + ventilation volume), that is, the gas concentration, leakage volume and ventilation volume in the corridor satisfy the following relationship:

Among them, C _Corridor represents the gas concentration in the corridor, Q _Leakage represents the leakage flow, and Q _Ventilation represents the ventilation volume.

Furthermore, the calculation formula of the ventilation volume can be:

Q _ventilation = nV _{pipe gallery}

Where n represents the ventilation frequency, and V _corridor represents the corridor volume.

Correspondingly, the calculation formula of the ventilation frequency is:

Among them, n represents ventilation frequency, Q _ventilation represents ventilation volume, V _corridor represents corridor volume, and Q _leakage represents leakage flow. In addition, according to the calculation formula of Q _leakage, we can know:

Furthermore, in order to further improve safety, after the ventilation frequency is determined, the ventilation frequency can be amplified, and the amplified ventilation frequency can be used as the ventilation frequency. Therefore, the calculation formula for the amplified ventilation frequency can be:

Among them, α>1 represents the amplification factor.

In one implementation, α is set to 1.2, and accordingly, the ventilation frequency can satisfy:

Right now:

In summary, this embodiment provides a ventilation method after a hydrogen-blended natural gas pipeline leaks in an integrated pipe gallery, the method comprising obtaining a first alarm concentration, a second alarm concentration, and an interval between the first alarm concentration and the second alarm concentration of a leakage alarm; determining the leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time, and the pipeline operating pressure of the hydrogen-blended natural gas pipeline; calculating the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio; determining the ventilation frequency corresponding to the pipe gallery according to the leakage flow, as well as the pipe gallery volume and gas concentration of the pipe gallery, and controlling the pipe gallery to be ventilated according to the ventilation frequency. This application utilizes the response interval time of different alarm levels of the gas concentration alarm, the pipeline operating pressure, and the hydrogen blending ratio to determine the ventilation frequency corresponding to the pipe gallery, and ventilates according to the ventilation frequency, so that the concentration of the leaked hydrogen-blended natural gas in the pipe gallery is reduced to below the explosion limit within the fastest response time to ensure the safety of the pipe gallery.

In order to further illustrate the ventilation method after leakage of the hydrogen-blended natural gas pipeline in the integrated pipeline gallery provided by this embodiment, a specific example is described below.

For a typical urban gas corridor, according to the national standard GB 50838-2015 "Technical Specifications for Urban Integrated Corridor Engineering", the corridor dimensions are 200 meters long, 1.6 meters wide, and 2.4 meters high. The gas pipeline in the corridor is DN300, with a wall thickness of 4.6mm, a pipeline operating pressure of 0.2MPa, a hydrogen blending ratio of 20%, and a natural gas temperature of 288K. When the hydrogen-blended natural gas pipeline leaked, two leak detection alarms first detected the combustible gas, and the alarm concentration of the leak alarm on the downwind side went from 0.7% to 1.4% over 12s.

Step 1: Calculate the physical properties of hydrogen-doped natural gas based on the hydrogen doping ratio λ: density ρ = 0.5347 kg/m3; gas constant R = 629.9 J/(kg·K); specific heat ratio 1.364; lower explosion limit LEL = 4.8%.

Step 2: The alarm concentration increases from 0.7% to 1.4% over 12 seconds, and the pipeline operating pressure is 0.2MPa, then:

Get: d≈10mm.

Step 3: Calculate the orifice coefficient at the leak hole

Among them, d=10mm, L=4.6mm, λ=20.

Step 4: Calculate the flow rate at the leak hole

Step 5: Determine the allowable combustible gas concentration and corridor volume in the corridor

The lower explosion limit of combustible gas is taken as the combustible gas concentration in the pipe gallery:

C _{Pipeline corridor} = 4.8%

V _{Pipeline corridor} = 200 × 1.6 × 2.4 m ³ = 768 m ³

Step 6: Take the magnification factor as 1.2, then:

That is, after the leakage alarm is activated, when the ventilation volume is 6.5 times/h, the concentration of combustible gas in the corridor can be guaranteed to be below the lower explosion limit, and no fire or explosion will occur.

Based on the ventilation method after leakage of hydrogen-blended natural gas pipeline in the above-mentioned integrated pipe gallery, this embodiment provides a ventilation system for leakage of hydrogen-blended natural gas pipeline in the pipe gallery, as shown in FIG3 , the system comprises:

An acquisition module 100 is used to acquire a first alarm concentration, a second alarm concentration, and an interval between the first alarm concentration and the second alarm concentration of a leakage alarm;

A determination module 200, configured to determine a leakage hole diameter of the hydrogen-blended natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time, and the pipeline operating pressure of the hydrogen-blended natural gas pipeline;

A calculation module 300, configured to calculate the leakage flow of the hydrogen-blended natural gas pipeline according to the leakage hole diameter and the hydrogen blending ratio;

The control module 400 is used to determine the ventilation frequency corresponding to the pipe gallery according to the leakage flow, the pipe gallery volume and the gas concentration of the pipe gallery, and control the pipe gallery to be ventilated according to the ventilation frequency.

Based on the ventilation method after leakage of the hydrogen-blended natural gas pipeline in the above-mentioned integrated pipeline gallery, this embodiment provides a computer-readable storage medium, which stores one or more programs, and the one or more programs can be executed by one or more processors to implement the steps in the ventilation method after leakage of the hydrogen-blended natural gas pipeline in the integrated pipeline gallery as described in the above-mentioned embodiment.

Based on the ventilation method after the leakage of the hydrogen-blended natural gas pipeline in the above-mentioned integrated pipe gallery, the present application also provides a terminal device, as shown in Figure 4, which includes at least one processor (processor) 20; display screen 21; and memory (memory) 22, and may also include a communication interface (Communications Interface) 23 and a bus 24. Among them, the processor 20, the display screen 21, the memory 22 and the communication interface 23 can communicate with each other through the bus 24. The display screen 21 is set to display the user guide interface preset in the initial setting mode. The communication interface 23 can transmit information. The processor 20 can call the logic instructions in the memory 22 to execute the method in the above embodiment.

In addition, the logic instructions in the memory 22 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product.

The memory 22, as a computer-readable storage medium, can be configured to store software programs, computer executable programs, such as program instructions or modules corresponding to the methods in the embodiments of the present disclosure. The processor 20 executes functional applications and data processing by running the software programs, instructions or modules stored in the memory 22, that is, implementing the methods in the above embodiments.

The memory 22 may include a program storage area and a data storage area, wherein the program storage area may store an operating system and at least one application required for a function; the data storage area may store data created according to the use of the terminal device, etc. In addition, the memory 22 may include a high-speed random access memory and may also include a non-volatile memory. For example, a variety of media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, may also be a transient storage medium.

In addition, the specific process of loading and executing the multiple instruction processors in the above-mentioned storage medium and the terminal device has been described in detail in the above-mentioned method, and will not be described one by one here.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims (10)

1. A ventilation method for a hydrogen-doped natural gas pipeline in a comprehensive pipe rack after leakage is characterized by comprising the following steps:

acquiring a first alarm concentration and a second alarm concentration of a leakage alarm and the interval time of the first alarm concentration and the second alarm concentration;

determining the diameter of a leakage hole of the hydrogen-doped natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time and the pipeline operation pressure of the hydrogen-doped natural gas pipeline;

calculating the leakage flow of the hydrogen-doped natural gas pipeline according to the diameter of the leakage hole and the hydrogen doping ratio;

according to leak the flow, and the piping lane volume and the gas concentration of piping lane, confirm the ventilation frequency that the piping lane corresponds, and control the piping lane according to ventilation frequency ventilates.

2. The ventilation method for the hydrogen-doped natural gas pipeline in the comprehensive pipe rack according to claim 1, wherein when two adjacent leakage alarms give an alarm, the leakage alarm is a leakage alarm positioned on the downwind side of ventilation in the pipe rack.

3. The ventilation method of the utility tunnel after the leakage of the hydrogen-loaded natural gas pipeline according to claim 1, wherein the determining the diameter of the leakage hole of the hydrogen-loaded natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time and the pipeline operating pressure of the hydrogen-loaded natural gas pipeline specifically comprises:

determining a concentration change value according to the first alarm concentration and the second alarm concentration;

reading the pipeline running pressure of the hydrogen-doped natural gas pipeline, and calculating the diameter of the leakage hole of the hydrogen-doped natural gas pipeline based on the corresponding relation among the pipeline running pressure, the concentration change value, the interval time and the diameter of the leakage hole, wherein the corresponding relation is as follows:

wherein Δ C represents a concentration change value; Δ t represents the interval time, d is the leak hole diameter; p ₂ Denotes the pipeline operating pressure, K ₁ ，K ₂ Are known coefficients.

4. The ventilation method for the natural gas-doped pipeline in the comprehensive pipe rack after leakage according to claim 1, wherein the step of calculating the leakage flow of the natural gas-doped pipeline according to the diameter of the leakage hole and the hydrogen-doped ratio specifically comprises the following steps:

reading the absolute pressure, the hydrogen loading ratio, the wall thickness and the natural gas temperature of the hydrogen-loaded natural gas pipeline;

calculating the area of the leakage hole according to the diameter of the leakage hole, and calculating the coefficient of the leakage hole according to the diameter of the leakage hole, the hydrogen doping ratio and the thickness of the pipeline wall;

and calculating the leakage flow according to the leakage hole coefficient, the leakage hole area, the pipeline absolute pressure and the natural gas temperature.

5. The ventilation method for the hydrogen-doped natural gas pipeline in the comprehensive pipe rack after leakage according to claim 4, wherein the calculation formula of the leakage hole coefficient is as follows:

wherein,

the leakage hole coefficient is shown, d is the leakage hole diameter, l is the pipe wall thickness, lambda is the hydrogen loading ratio, and a, b and c are known coefficients.

6. The ventilation method for the natural gas pipeline with hydrogen content in the comprehensive pipe rack according to claim 4, wherein the calculation formula of the leakage flow is as follows:

wherein Q is _{Leakage of} The flow rate of the leak is indicated,

indicating the leakage hole coefficient, P ₂ Indicating the absolute pressure of the pipe, T ₂ Represents the temperature of the hydrogen-loaded natural gas in the hydrogen-loaded natural gas pipeline, A _or Denotes the area of the leakage hole, d denotes the diameter of the leakage hole, gamma denotes the specific heat ratio of the hydrogen-doped natural gas, R denotes the gas constant of the hydrogen-doped natural gas, ρ ₃ Indicating the gas density of the hydrogen-loaded natural gas at ambient conditions.

7. The ventilation method of the utility tunnel after the leakage of the hydrogen-doped natural gas pipeline in the utility tunnel according to the claim 1, wherein the step of determining the ventilation frequency volume corresponding to the pipeline tunnel according to the leakage flow, the pipeline tunnel volume and the gas concentration of the pipeline tunnel comprises the following steps:

determining ventilation quantity corresponding to the pipe gallery according to the leakage flow and the gas concentration of the pipe gallery;

according to the ventilation volume and the pipe gallery volume of pipe gallery, confirm the ventilation frequency, wherein, the computational formula of ventilation frequency is:

wherein n represents the ventilation frequency, Q _Ventilation Indicates the ventilation volume, V _{Pipe gallery} Denotes the volume of the pipe gallery, alpha>1 denotes an amplification factor.

8. A ventilation system for a hydrogen loaded natural gas pipeline leak in a pipeline corridor, said system comprising:

the acquisition module is used for acquiring a first alarm concentration and a second alarm concentration of the leakage alarm and the interval time of the first alarm concentration and the second alarm concentration;

the determining module is used for determining the diameter of a leakage hole of the hydrogen-doped natural gas pipeline according to the first alarm concentration, the second alarm concentration, the interval time and the pipeline operating pressure of the hydrogen-doped natural gas pipeline;

the calculation module is used for calculating the leakage flow of the hydrogen-doped natural gas pipeline according to the diameter of the leakage hole and the hydrogen doping ratio;

and the control module is used for determining the ventilation frequency corresponding to the pipe gallery according to the leakage flow, the pipe gallery volume and the gas concentration of the pipe gallery, and controlling the pipe gallery to ventilate according to the ventilation frequency.

9. A computer readable storage medium, storing one or more programs, which are executable by one or more processors, to perform the steps of the method for ventilation of a post-leakage pipeline of hydrogen loaded natural gas in a utility tunnel according to any one of claims 1-7.

10. A terminal device, comprising: a processor, a memory, and a communication bus; the memory has stored thereon a computer readable program executable by the processor;

the communication bus realizes connection communication between the processor and the memory;

the processor, when executing the computer readable program, performs the steps of the method for ventilation after a leak in a loading natural gas pipeline in a utility tunnel according to any one of claims 1 to 7.

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