A steam cloud explosion hazard analysis method and analysis system based on natural gas pipeline leakage

Abstract

The present invention discloses a steam cloud explosion hazard analysis method and analysis system based on natural gas pipeline leakage, wherein the analysis method includes mapping the fire source position to a satellite map, and drawing a plurality of array-arranged grids on the satellite map with the fire source position as the center to obtain a grid satellite map; using the leakage source information to calculate the total mass of the fuel in the steam cloud, and using the total mass of the fuel in the steam cloud to analyze the death radius and property loss radius of the steam cloud explosion, so as to determine the death area, property loss area and collapsed building area; using the grid satellite map, according to the distance between each grid and each building within the steam cloud explosion hazard range, the population density of each grid is calculated; using the population density, death area, property loss area and collapsed building area of ​​each grid, the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by the secondary collapse accident are calculated to analyze the total number of deaths caused by the steam cloud explosion of natural gas leakage. The present invention can improve the accuracy of the analysis of the lethality of the steam cloud explosion of natural gas leakage.

Description

Technical Field

[0001] The present invention belongs to the field of public safety risk assessment and relates to a steam cloud explosion hazard analysis method and analysis system based on natural gas pipeline leakage. Background Art

[0002] During the operation of natural gas pipelines, external interference, corrosion, construction defects, misoperation, ground movement, etc. may cause pipeline ruptures or leaks, resulting in serious consequences.

[0003] After a natural gas pipeline leaks, due to the high internal pressure and high natural gas concentration, in real life, methane is the main gas, and ignition and explosion will not occur near the leak point. After a natural gas leaks, it mixes with a sufficient amount of air under the action of wind to form a large-scale cloud, thus meeting the explosion limit of the gas. Under certain conditions, ignition will occur. At the same time, due to local constraints such as buildings, the flame is accelerated, and a steam cloud explosion occurs.

[0004] Steam cloud explosions caused by natural gas leaks can lead to serious accident consequences. The huge pressure generated by steam cloud explosions will not only cause damage and losses to buildings and equipment, but also cause harm to people in the range of the steam cloud explosion. Therefore, it is necessary to conduct a risk assessment of the accident consequences of steam cloud explosions caused by natural gas leaks, conduct a quantitative analysis of the severity of the accident consequences caused by steam cloud explosions, and provide information references for emergency rescue and command for decision makers and designers.

[0005] The risk of steam cloud explosion caused by natural gas pipeline leakage is closely related to population distribution. There are many scholars who conduct risk assessment based on population distribution, but most of them assume that the population distribution in the study area is fixed during the risk assessment process, which is inconsistent with the actual characteristic that the urban population flow changes greatly. Therefore, this application provides a steam cloud explosion hazard analysis method and analysis system based on natural gas pipeline leakage. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a steam cloud explosion hazard analysis method and analysis system based on natural gas pipeline leakage, which can improve the accuracy of the lethality analysis of steam cloud explosion caused by natural gas leakage.

[0007] To achieve the above object, the present invention is implemented by adopting the following technical solutions:

[0008] In one aspect, the present invention provides a method for analyzing the hazard of a steam cloud explosion based on a natural gas pipeline leak, comprising the following steps:

[0009] Obtain leakage source information of natural gas pipeline leakage;

[0010] Get the location of the fire source;

[0011] The fire source location is mapped to a satellite map, and a plurality of grids arranged in an array are drawn on the satellite map with the fire source location as the center to obtain a grid satellite map;

[0012] The total mass of the fuel in the steam cloud is calculated using the leakage source information, and based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the death radius and property loss radius of the steam cloud explosion;

[0013] On the grid satellite map, the fire source location is taken as the origin, and the death radius is used as the radius to determine the death area, the property loss area is used as the radius to determine the property loss area, and the collapsed building area is used as the radius;

[0014] Using grid satellite maps, the population density of each grid is calculated based on the distance between each grid and each building within the hazard range of the steam cloud explosion;

[0015] The population density, death area, property loss area and collapsed building area of ​​each grid were used to calculate the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by secondary collapse accidents. The total number of deaths caused by the steam cloud explosion due to natural gas leakage was analyzed based on the number of deaths caused by the shock wave and the number of deaths caused by secondary collapse accidents.

[0016] Furthermore, the leakage source information includes the leakage hole diameter, medium pressure in the natural gas pipeline, gas temperature and leakage time.

[0017] Furthermore, L×K array-arranged grids are drawn on the satellite map with the fire source location as the center.

[0018] Furthermore, the size of each grid is 20×20m 2 .

[0019] Furthermore, the method of calculating the total mass of the fuel in the steam cloud using the leakage source information and analyzing the death radius and property loss radius of the steam cloud explosion using the total mass of the fuel in the steam cloud based on the TNT equivalent method includes:

[0020] The total mass of fuel in the vapor cloud is calculated using the leak source information using the following formula:

[0021]

[0022]

[0023]

[0024] Q eff =2λQ max

[0025] W f =Q eff·t

[0026] In the formula, a0 is the sound velocity of the gas, γ is the adiabatic coefficient, R is the gas constant, T is the gas temperature, m is the gas molecular weight, Q max is the maximum value of pipeline leakage rate, is the flow factor, C d is the leakage coefficient, d is the diameter of the leakage hole, P is the medium pressure in the natural gas pipeline, Q eff is the equivalent leakage rate, λ is the attenuation coefficient, W f is the total mass of fuel in the steam cloud, and t is the leakage time;

[0027] Based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the death radius of the steam cloud explosion:

[0028]

[0029]

[0030] Where W TNT is the TNT equivalent of the steam cloud, α is the efficiency factor in the steam cloud explosion, Q f is the explosion heat of the vapor cloud, Q TNT is the explosion heat of TNT, R1 is the death radius;

[0031] Based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the property loss radius of the steam cloud explosion:

[0032]

[0033] In the formula, R d is the property damage radius.

[0034] Furthermore, the said grid satellite map is used to calculate the population density of each grid according to the distance between each grid and each building within the hazard range of the steam cloud explosion:

[0035] The population density of each grid is calculated by the following formula:

[0036] ρ0=ρ′0 / (1-β)

[0037]

[0038]

[0039] Where ρ0 is the initial population density within the steam cloud explosion hazard range, ρ′0 is the statistical population density within the steam cloud explosion hazard range, β is the coverage rate of green space and water within the steam cloud explosion hazard range, and ρ kl (r ij) is the k-th row and l-th column grid, and the distance between the j-th building in the i-th type of building is r ij The population density at that time, where j = 1, ..., n, i = 1, 2 or 3, and i = 1 is a commercial building, i = 2 is an educational building, i = 3 is a medical building, α i is the clustering coefficient of different types of buildings, r ij is the distance between the k-th row and l-th column grid and the j-th building in the i-th type of building, r ij0 is the influence radius of the jth building in the i-th type of building, σ is the constraint parameter of the information entropy of the population spatial variation in the hazard range of the reaction steam cloud explosion, ρ kl is the population density of the grid in the kth row and lth column, and P(i) is the weight of the i-th type of building.

[0040] Further, the calculation of the number of deaths caused by the shock wave of the steam cloud explosion using the population density and the death area of ​​each grid includes:

[0041] The number of deaths caused by the shock wave of the steam cloud explosion is calculated by the following formula:

[0042] N kl =ρ kl ×S

[0043] P Dkl =S kl / S

[0044] ΔN kl =P Dkl ×N kl

[0045]

[0046] Where N kl is the population in the kth row and lth column of the grid, S is the grid area, P Dkl is the death probability of the population in the kth row and lth column grid, S kl is the overlapping area between the grid in the kth row and the lth column of the grid satellite map and the death zone, ΔN kl is the number of deaths caused by the shock wave in the grid of the kth row and the lth column, and N1 is the number of deaths caused by the shock wave of the steam cloud explosion.

[0047] Furthermore, the calculation of the number of deaths caused by the secondary collapse accident using the population density, property loss area and collapsed building area of ​​each grid includes:

[0048] The number of deaths caused by secondary collapse accidents is determined by the following formula:

[0049]

[0050] Among them, N2 is the number of deaths caused by the secondary collapse accident, P TA is the probability of death caused by building failure under blast load, kl It is the sum of the overlapping areas of the grid in the kth row and the lth column in the grid satellite map and the collapsed building.

[0051] Furthermore, the total number of deaths caused by the natural gas leak steam cloud explosion according to the number of deaths caused by the shock wave and the number of deaths caused by the secondary collapse accident includes:

[0052] The total number of deaths caused by natural gas leak vapor cloud explosions is determined by the following formula:

[0053] N=N1+N2

[0054] Where N is the total number of deaths caused by natural gas leak steam cloud explosion.

[0055] On the other hand, the present invention provides a steam cloud explosion hazard analysis system based on natural gas pipeline leakage, comprising:

[0056] A leakage source information unit, used to obtain leakage source information of natural gas pipeline leakage;

[0057] Ignition unit, used to obtain the location of the fire source;

[0058] A grid setting unit is used to map the fire source location to a satellite map, and draw a plurality of grids arranged in an array on the satellite map with the fire source location as the center to obtain a grid satellite map;

[0059] Hazard radius unit, used to calculate the total mass of fuel in the steam cloud using the leakage source information, and based on the TNT equivalent method, use the total mass of fuel in the steam cloud to analyze the death radius and property loss radius of the steam cloud explosion;

[0060] The hazard area unit is used to determine the death area with the fire source location as the origin and the property loss area and collapsed building area with the property loss radius as the radius on the grid satellite map;

[0061] The grid population density unit is used to calculate the population density of each grid according to the distance between each grid and each building within the steam cloud explosion hazard range using the grid satellite map;

[0062] The hazard analysis unit is used to calculate the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by secondary collapse accidents by using the population density, death area, property loss area and collapsed building area of ​​each grid, and to analyze the total number of deaths caused by the steam cloud explosion of natural gas leakage based on the number of deaths caused by the shock wave and the number of deaths caused by secondary collapse accidents.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] The present invention divides an area into several grids, and calculates the population density of each grid according to the land attributes of the area covered by the grid and the distance between the grid and the building, so as to simulate the population distribution. The present invention analyzes the total number of deaths by analyzing the number of deaths caused by shock waves and the number of deaths caused by secondary collapse accidents, so as to improve the accuracy of the analysis of the mortality rate of steam cloud explosion caused by natural gas leakage, provide a reference basis for the setting of safety precautions, and protect the lives and property of the people. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 The figure is a flow chart of an embodiment of a method for analyzing the hazard of a steam cloud explosion based on a natural gas pipeline leak according to the present invention;

[0066] Figure 2 Shown is a schematic diagram of an embodiment of a grid satellite map of the present invention;

[0067] Figure 3 Shown is a bar graph of an embodiment comparing the analysis results of the present invention with those of the traditional method;

[0068] Figure 4 Shown is an image diagram of population density of each grid in Example 3 of the present invention. DETAILED DESCRIPTION

[0069] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0070] Example 1

[0071] This embodiment introduces a steam cloud explosion hazard analysis method based on natural gas pipeline leakage.

[0072] refer to Figure 1 The steam cloud explosion hazard analysis method based on natural gas pipeline leakage in this embodiment includes the following steps:

[0073] S1 obtains leakage source information of natural gas pipeline leakage.

[0074] In the application, the leakage source information includes the leakage hole diameter, medium pressure in the natural gas pipeline, gas temperature and leakage time.

[0075] S2 obtains the location of the fire source.

[0076] In the application, the fire source location is the steam cloud explosion location.

[0077] S3 maps the fire source location to a satellite map, and draws a number of array-arranged grids on the satellite map with the fire source location as the center to obtain a grid satellite map.

[0078] In the application, L×K grids are drawn on the satellite map with the fire source as the center, and the size of each grid is 20×20m 2 , where L is the number of columns in the array and K is the number of rows in the array.

[0079] S4 uses the leakage source information to calculate the total mass of the fuel in the steam cloud, and based on the TNT equivalent method, uses the total mass of the fuel in the steam cloud to analyze the death radius and property loss radius of the steam cloud explosion;

[0080] S5 uses the fire source location as the origin on the grid satellite map, and uses the death radius as the radius to determine the death area, the property loss area and the collapsed building area as the radius;

[0081] S6 uses grid satellite maps to calculate the population density of each grid based on the distance between each grid and each building within the steam cloud explosion hazard range;

[0082] S7 uses the population density, death area, property loss area and collapsed building area of ​​each grid to calculate the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by secondary collapse accidents, and analyzes the total number of deaths caused by the steam cloud explosion of natural gas leakage based on the number of deaths caused by the shock wave and the number of deaths caused by secondary collapse accidents.

[0083] The present invention divides an area into several grids, and calculates the population density of each grid according to the land attributes of the area covered by the grid and the distance between the grid and the building, so as to simulate the population distribution. The present invention analyzes the total number of deaths by analyzing the number of deaths caused by shock waves and the number of deaths caused by secondary collapse accidents, so as to improve the accuracy of the analysis of the mortality rate of steam cloud explosion caused by natural gas leakage, provide a reference basis for the setting of safety precautions, and protect the lives and property of the people.

[0084] Example 2

[0085] Based on Example 1, this example introduces in detail the analysis method of death radius and property loss radius, the calculation method of population density of each grid, the number of deaths caused by steam cloud explosion shock wave, the number of deaths caused by secondary collapse accidents, and the total number of deaths caused by natural gas leakage steam cloud explosion.

[0086] 1. Death radius and property loss radius

[0087] The total mass of the fuel in the steam cloud is calculated using the leakage source information, and based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the death radius and property radius of the steam cloud explosion, including:

[0088] S41 uses the leak source information to calculate the total mass of fuel in the vapor cloud using the following formula:

[0089]

[0090]

[0091]

[0092] Q eff =2λQ max

[0093] W f =Q eff ·t

[0094] Where a0 is the speed of sound of the gas, the unit of which is m / s in the application, γ is the adiabatic coefficient, R is the gas constant, T is the gas temperature, m is the gas molecular weight, the unit of which is kg / mol in the application, Q max The maximum value of pipeline leakage rate, in application, the unit is kg / s. is the flow factor, C d is the leakage coefficient, which is 0.6 in the application, d is the diameter of the leakage hole, which is expressed in meters in the application, P is the medium pressure in the natural gas pipeline, which is expressed in Pa in the application, Q eff is the equivalent leakage rate, λ is the attenuation coefficient. The value of the attenuation coefficient in the application depends on the parameters such as the pipeline size and the pressure at the time of failure. In this embodiment, the attenuation coefficient is 0.35. f is the total mass of fuel in the vapor cloud, t is the leakage time, and the unit in the application is seconds.

[0095] S42 is based on the TNT equivalent method and uses the total mass of the fuel in the steam cloud to analyze the death radius of the steam cloud explosion:

[0096]

[0097]

[0098] Where W TNT is the TNT equivalent of the steam cloud, and the unit in the application is kg. α is the efficiency factor in the steam cloud explosion, and is related to the volume fraction of the combustible gas involved in the explosion. In this embodiment, the efficiency factor in the steam cloud explosion is 3%. Q f is the explosion heat of the vapor cloud, in application units MJ / kg, Q TNT is the explosion heat of TNT. In application, the explosion power is enhanced due to the ground reflection effect. For ground explosion, it should be multiplied by the ground explosion coefficient of 1.8. The explosion heat of TNT in this embodiment is 4.52 MJ / kg. R1 is the death radius.

[0099] S43 is based on the TNT equivalent method and uses the total mass of the fuel in the steam cloud to analyze the property loss radius of the steam cloud explosion:

[0100]

[0101] In the formula, R d is the property damage radius.

[0102] In actual application of this embodiment, in order to estimate the casualties and property losses that may be caused by the explosion, the injury range caused by the accident is usually divided into: a death area, a serious injury area, a minor injury area and a property loss area.

[0103] (1) Death zone

[0104] Since people in this area are close to the fire source, they will almost certainly die if they do not take protective measures. Few people will survive. The death radius is recorded as R1.

[0105] (2) Severely injured area

[0106] The shock wave overpressure in this area is 44k Pa. Almost all people in the area are seriously injured, with only a few being slightly injured. The radius of serious injuries is recorded as R2:

[0107] ΔP1=0.137Z1 -3 +0.119Z1 -2 +0.267Z1 -1 -0.019

[0108]

[0109]

[0110] E=W TNT Q TNT

[0111] Wherein, ΔP1 is the shock wave overpressure in the severely injured area, and the unit in the application is Pa; Z1 is the intermediate factor of the severely injured area; P0 is the ambient pressure, and the unit in the application is Pa; E is the total explosion energy, and the unit in the application is joule.

[0112] (3) Minor injury area

[0113] The shock wave overpressure in this area is 17k Pa. Since the people in the area are far away from the explosion area, they are less affected by the steam cloud explosion. Most people are only slightly injured and rarely die. The radius of minor injuries is R3:

[0114] ΔP2=0.137Z2 -3 +0.119Z2 -2 +0.267Z2 -1 -0.019

[0115]

[0116]

[0117] Wherein, ΔP2 is the shock wave overpressure in the lightly injured area, and the unit in the application is Pa; Z2 is the intermediate factor of the lightly injured area.

[0118] (4) Property damage area

[0119] The steam cloud explosion causes great damage to the surrounding buildings. The property loss area is the range of secondary damage to the buildings under the action of the explosion shock wave, which tends to collapse. The property loss radius is R d .

[0120] In the application, a building collapses in a property damage area.

[0121] 2. Population density of each grid

[0122] In traditional pipeline steam cloud explosion risk assessment, the location of the steam cloud explosion caused by natural gas leakage is uncertain, so the population distribution in the area where the steam cloud explosion occurs is also uncertain. In previous risk assessment studies, the average population density was mostly used as the basis for calculation of population distribution.

[0123] The average population density is a constant value of uniform distribution, but for real cities or urban areas, the population is not evenly distributed. The population is mainly located in residential areas. For green land and water bodies, the population is not distributed in these areas. At the same time, the population density of a small area is affected by many factors, mainly commercial, educational, medical and other conditions. Good commercial, educational, medical and other conditions have a certain aggregation effect on the population.

[0124] Therefore, this embodiment uses the grid satellite map to calculate the population density of each grid according to the distance between each grid and each building within the steam cloud explosion hazard range, including:

[0125] The population density of each grid is calculated by the following formula:

[0126] ρ0=ρ′0 / (1-β)

[0127]

[0128]

[0129] Where ρ0 is the initial population density within the steam cloud explosion hazard range, ρ′0 is the statistical population density within the steam cloud explosion hazard range, β is the coverage rate of green space and water within the steam cloud explosion hazard range, and ρ kl (r ij ) is the k-th row and l-th column grid, and the distance between the j-th building in the i-th type of building is r ijThe population density at that time, where j = 1, ..., n, n is the number of all buildings of type i in the hazard range of the steam cloud explosion. In order to simplify the calculation in the application, j = 1, and only the building closest to the fire source is selected for calculation; in addition, i = 1, 2 or 3, and i = 1 is a commercial building, i = 2 is an educational building, i = 3 is a medical building, α i is the clustering coefficient of different types of buildings, r ij is the distance between the k-th row and l-th column grid and the j-th building in the i-th type of building, where r ij <R d , r ij0 is the influence radius of the jth building in the i-th type of building. In the application, r ij0 The size of is affected by the area of ​​the building, σ is the constraint parameter of the population spatial change information entropy of the reaction steam cloud explosion hazard range. In the application, urban development includes growth, maturity and old age stages. The constraint parameters of the population spatial change information entropy of cities in different stages are different. Since my country's urban development and construction are still in the early stage of maturity, some small and medium-sized towns are still in the development stage. Therefore, in this embodiment, σ=1.2. ρ kl is the population density of the grid in the kth row and lth column, P(i) is the weight of the i-th type of building, and in the application, it is obtained by fitting the historical population data of the steam cloud explosion hazard range for more than three years through matelab.

[0130] 3. Number of deaths caused by the shock wave of steam cloud explosion

[0131] The number of deaths caused by the shock wave of the steam cloud explosion is calculated using the population density and death area of ​​each grid, including:

[0132] The number of deaths caused by the shock wave of the steam cloud explosion is calculated by the following formula:

[0133] N kl =ρ kl ×S

[0134] P Dkl =S kl / S

[0135] ΔN kl =P Dkl ×N kl

[0136]

[0137] Where N kl is the population in the kth row and lth column of the grid, S is the grid area, P Dkl is the death probability of the population in the kth row and lth column grid, S kl is the overlapping area between the grid in the kth row and the lth column of the grid satellite map and the death zone, ΔNkl is the number of deaths caused by the shock wave in the grid of the kth row and the lth column, and N1 is the number of deaths caused by the shock wave of the steam cloud explosion.

[0138] (IV) Number of deaths caused by secondary collapse accidents

[0139] The number of deaths caused by secondary collapse accidents is calculated using the population density, property loss area and collapsed building area of ​​each grid, including:

[0140] The number of deaths caused by secondary collapse accidents is determined by the following formula:

[0141]

[0142] Among them, N2 is the number of deaths caused by the secondary collapse accident, P T is the probability of death caused by building failure under blast load. Refer to Table 1 for application. A kl It is the sum of the overlapping areas of the grid in the kth row and the lth column in the grid satellite map and the collapsed building.

[0143] Table 1 Probability of death caused by building failure on different floors

[0144] Building Types 1-3 floors 4-7th floor 8 floors and above Timber Construction 0.296 — — Masonry Building 0.346 0.348 — Brick-concrete structure building 0.273 0.407 0.183 Reinforced concrete building 0.385 0.411 0.442

[0145] (V) Total number of deaths caused by natural gas leak steam cloud explosion

[0146] The total number of deaths caused by natural gas leak steam cloud explosions, based on the number of deaths caused by shock waves and the number of deaths caused by secondary collapse accidents, includes:

[0147] The total number of deaths caused by natural gas leak vapor cloud explosions is determined by the following formula:

[0148] N=N1+N2

[0149] Where N is the total number of deaths caused by natural gas leak steam cloud explosion.

[0150] Example 3

[0151] This example takes the B event in area A as the background to analyze the hazards of steam cloud explosion caused by natural gas pipeline leakage.

[0152] The cause of event B was that the natural gas pipeline broke due to corrosion, causing natural gas leakage. The leakage source was located under the building, the pipeline pressure was 0.25MPa, and the pipeline diameter was 70mm. In addition, the southeast wind in area A was 3m / s all year round, the ambient temperature was 300K, and the relative humidity was 50%.

[0153] According to reports, the parameters of event B are as follows: the medium pressure P in the natural gas pipeline is 361 325Pa; the molecular weight M of methane is 0.016 04kg / mol; the gas constant R is 8.31J / (mol·K); the gas temperature T is 300K; the attenuation coefficient λ is 0.3; the explosion heat of the vapor cloud Q f 55505 kJ / kg; the explosion heat of TNT is Q TNT 4.52×10 3 kJ / kg; the adiabatic index γ of the gas is 1.3; the leakage time t is 3840s; the intermediate factor Z1 of the seriously injured area is 1.089; and the intermediate factor Z2 of the slightly injured area is 1.9569.

[0154] S11 This embodiment calculates the maximum value Q of the pipeline leakage rate based on the above parameters and the steam cloud explosion hazard analysis method described in Example 1 or 2 max and equivalent leakage rate Q eff , the total mass of fuel in the steam cloud W f :

[0155]

[0156] Q eff =2λQ max =2×0.3×1.473=0.884kg / s

[0157] W f =Q eff ·t=0.884×3840=3393.088kg

[0158] S12 In this embodiment, according to the above parameters, the maximum value of the pipeline leakage rate Q max and equivalent leakage rate Q eff , the total mass of the fuel in the steam cloud and the steam cloud explosion hazard analysis method described in Example 1 or 2 to calculate the death radius R1, the serious injury radius R2, the minor injury radius R3 and the property loss radius R d :

[0159]

[0160] E=W TNT Q TNT =225×4520×10 3 =1.017×10 9 J;

[0161]

[0162]

[0163]

[0164]

[0165]

[0166]

[0167] S13, mapping the fire source location to a satellite map, and drawing a plurality of grids arranged in an array on the satellite map with the fire source location as the center, to obtain a grid satellite map, and on the grid satellite map, taking the fire source location as the origin, determining the death area with the death radius as the radius, and determining the property loss area with the property loss radius as the radius, respectively, with reference to Figure 2 .

[0168] In addition, according to relevant statistical data, the average population density in Area A is 3942 people / km 2 , the area includes 40.13% of non-building land, that is, green land, so the initial population density of area A is:

[0169]

[0170] S14 This embodiment uses the grid satellite map to analyze the land attributes and building distance of the area covered by each grid to calculate the population density of each grid, and calculates the population density of each grid according to the population density, death radius R1, property loss radius R2, etc. d The steam cloud explosion hazard analysis method described in Example 1 or 2 calculates the number of deaths caused by shock waves, the number of deaths caused by secondary collapse accidents, and the total number of deaths caused by natural gas leak steam cloud explosions. The population density of each grid is as follows: Figure 4 shown.

[0171] S141 According to Figure 2 It can be seen that the fatal range involves the grid in the 3rd row and 3rd column, the grid in the 3rd row and 4th column, the grid in the 4th row and 3rd column, and the grid in the 4th row and 4th column. The number of deaths caused by the shock wave is calculated by the following formula:

[0172]

[0173] ΔN 34 =0.806

[0174] ΔN 43 =0.798

[0175] ΔN 44 =0.803

[0176]

[0177] According to the investigation report of the incident in Area A, after the steam cloud explosion, the building where the accident occurred collapsed, resulting in a large number of people being buried and crushed, causing death and serious injuries. Therefore, when conducting a risk assessment for this accident, it is also necessary to consider the situation where people were buried and crushed to death due to building collapse.

[0178] Through case analysis, we know that most of the buildings in area A are reinforced concrete buildings on the ground floor. T The value is 0.385. Therefore, in this embodiment, based on the steam cloud explosion hazard analysis method of natural gas pipeline leakage, the total number of deaths caused by the steam cloud explosion of natural gas leakage N is 13.663.

[0179]

[0180] In traditional pipeline steam cloud explosion risk assessment, the average population density is generally used as the calculation basis for population distribution. According to the traditional steam cloud explosion risk assessment calculation method, the number of deaths

[0181] refer to Figure 3 It can be seen that compared with the traditional analysis method, the analysis result of the steam cloud explosion hazard analysis method based on natural gas pipeline leakage in this embodiment of the present invention is more accurate, and can more accurately analyze the degree of hazard of steam cloud explosion caused by natural gas pipeline leakage and spread, provide a reference basis for the setting of safety precautions, and protect people’s lives and property.

[0182] Example 4

[0183] This embodiment introduces a steam cloud explosion hazard analysis system based on natural gas pipeline leakage, including:

[0184] A leakage source information unit, used to obtain leakage source information of natural gas pipeline leakage;

[0185] Ignition unit, used to obtain the location of the fire source;

[0186] A grid setting unit is used to map the fire source location to a satellite map, and draw a plurality of grids arranged in an array on the satellite map with the fire source location as the center to obtain a grid satellite map;

[0187] Hazard radius unit, used to calculate the total mass of fuel in the steam cloud using the leakage source information, and based on the TNT equivalent method, use the total mass of fuel in the steam cloud to analyze the death radius and property loss radius of the steam cloud explosion;

[0188] The hazard area unit is used to determine the death area with the fire source location as the origin and the property loss area and collapsed building area with the property loss radius as the radius on the grid satellite map;

[0189] The grid population density unit is used to calculate the population density of each grid according to the distance between each grid and each building within the steam cloud explosion hazard range using the grid satellite map;

[0190] The hazard analysis unit is used to calculate the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by secondary collapse accidents by using the population density, death area, property loss area and collapsed building area of ​​each grid, and to analyze the total number of deaths caused by the steam cloud explosion of natural gas leakage based on the number of deaths caused by the shock wave and the number of deaths caused by secondary collapse accidents.

[0191] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0192] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0193] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0194] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1The steps for the functions specified in one or more boxes.

[0195] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which all fall within the protection of the present invention.

Claims

1. A steam cloud explosion hazard analysis method based on natural gas pipeline leakage, characterized in that: The following steps are involved: Obtain leakage source information of natural gas pipeline leakage; Get the location of the fire source; The fire source location is mapped to a satellite map, and L×K arrayed grids are drawn on the satellite map with the fire source location as the center to obtain a grid satellite map; The total mass of the fuel in the steam cloud is calculated using the leakage source information, and based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the death radius and property loss radius of the steam cloud explosion; On the grid satellite map, the fire source location is taken as the origin, and the death radius is used as the radius to determine the death area, the property loss area is used as the radius to determine the property loss area, and the collapsed building area is used as the radius; Using grid satellite maps, the population density of each grid is calculated based on the distance between each grid and each building within the hazard range of the steam cloud explosion; The population density, death area, property loss area and collapsed building area of ​​each grid were used to calculate the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by secondary collapse accidents. The total number of deaths caused by the steam cloud explosion of natural gas leakage was analyzed based on the number of deaths caused by the shock wave and the number of deaths caused by secondary collapse accidents. The method of calculating the total mass of the fuel in the steam cloud using the leakage source information and analyzing the death radius and property loss radius of the steam cloud explosion using the total mass of the fuel in the steam cloud based on the TNT equivalent method includes: The total mass of fuel in the vapor cloud is calculated using the leak source information using the following formula: Q eff =2λQ max W f =Q eff ·t In the formula, a0 is the sound velocity of the gas, γ is the adiabatic coefficient, R is the gas constant, T is the gas temperature, m is the gas molecular weight, Q max is the maximum value of pipeline leakage rate, is the flow factor, C d is the leakage coefficient, d is the diameter of the leakage hole, P is the medium pressure in the natural gas pipeline, Q eff is the equivalent leakage rate, λ is the attenuation coefficient, W f is the total mass of fuel in the steam cloud, and t is the leakage time; Based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the death radius of the steam cloud explosion: Where W TNT is the TNT equivalent of the steam cloud, α is the efficiency factor in the steam cloud explosion, Q f is the explosion heat of the vapor cloud, Q TNT is the explosion heat of TNT, R1 is the death radius; Based on the TNT equivalent method, the total mass of the fuel in the steam cloud is used to analyze the property loss radius of the steam cloud explosion: In the formula, R d is the property damage radius; The grid satellite map is used to calculate the population density of each grid according to the distance between each grid and each building within the hazard range of the steam cloud explosion: The population density of each grid is calculated by the following formula: ρ0=ρ'0 / (1-β) Where ρ0 is the initial population density within the steam cloud explosion hazard range, ρ'0 is the statistical population density within the steam cloud explosion hazard range, β is the coverage rate of green space and water within the steam cloud explosion hazard range, ρ kl (r ij ) is the k-th row and l-th column grid, and the distance between the j-th building in the i-th type of building is r ij The population density at that time, where j = 1, ..., n, i = 1, 2 or 3, and i = 1 is a commercial building, i = 2 is an educational building, i = 3 is a medical building, α i is the clustering coefficient of different types of buildings, r ij is the distance between the k-th row and l-th column grid and the j-th building in the i-th type of building, r ij0 is the influence radius of the jth building in the i-th type of building, σ is the constraint parameter of the information entropy of the population spatial variation in the hazard range of the reaction steam cloud explosion, ρ kl is the population density of the grid at row k and column l, and P(i) is the weight of the i-th type of building; The method of calculating the number of deaths caused by the shock wave of the steam cloud explosion using the population density and the death area of ​​each grid includes: The number of deaths caused by the shock wave of the steam cloud explosion is calculated by the following formula: N kl =ρ kl ×S P Dkl =S kl / S ΔN kl =P Dkl ×N kl Where N kl is the population in the kth row and lth column of the grid, S is the grid area, P Dkl is the death probability of the population in the kth row and lth column grid, S kl is the overlapping area between the grid in the kth row and the lth column of the grid satellite map and the death zone, ΔN kl is the number of deaths caused by the shock wave in the grid of row k and column l, and N1 is the number of deaths caused by the shock wave of the steam cloud explosion; The method of calculating the number of deaths caused by secondary collapse accidents by using the population density, property loss area and collapsed building area of ​​each grid includes: The number of deaths caused by secondary collapse accidents is determined by the following formula: Among them, N2 is the number of deaths caused by the secondary collapse accident, P T A is the probability of death caused by building failure under blast load, kl It is the sum of the overlapping areas of the grid in the kth row and the lth column in the grid satellite map and the collapsed building; The total number of deaths caused by natural gas leak steam cloud explosions, based on the number of deaths caused by shock waves and the number of deaths caused by secondary collapse accidents, includes: The total number of deaths caused by natural gas leak vapor cloud explosions is determined by the following formula: N=N1+N2 Where N is the total number of deaths caused by steam cloud explosion due to gas leakage.

2. The steam cloud explosion hazard analysis method based on natural gas pipeline leakage according to claim 1 is characterized in that: The leakage source information includes the leakage hole diameter, medium pressure in the natural gas pipeline, gas temperature and leakage time.

3. The method for analyzing the hazard of steam cloud explosion due to natural gas pipeline leakage according to claim 1 is characterized in that: The size of each grid is 20×20m 2 .

4. An analysis system for the steam cloud explosion hazard analysis method based on natural gas pipeline leakage according to any one of claims 1 to 3, characterized in that: include: A leakage source information unit, used to obtain leakage source information of natural gas pipeline leakage; Ignition unit, used to obtain the location of the fire source; A grid setting unit is used to map the fire source location to a satellite map, and draw a plurality of grids arranged in an array on the satellite map with the fire source location as the center to obtain a grid satellite map; Hazard radius unit, used to calculate the total mass of fuel in the steam cloud using the leakage source information, and based on the TNT equivalent method, use the total mass of fuel in the steam cloud to analyze the death radius and property loss radius of the steam cloud explosion; The hazard area unit is used to determine the death area with the fire source location as the origin and the property loss area and collapsed building area with the property loss radius as the radius on the grid satellite map; The grid population density unit is used to calculate the population density of each grid according to the distance between each grid and each building within the hazard range of the steam cloud explosion using the grid satellite map; The hazard analysis unit is used to calculate the number of deaths caused by the shock wave of the steam cloud explosion and the number of deaths caused by secondary collapse accidents by using the population density, death area, property loss area and collapsed building area of ​​each grid, and to analyze the total number of deaths caused by the steam cloud explosion of natural gas leakage based on the number of deaths caused by the shock wave and the number of deaths caused by secondary collapse accidents.

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