A dangerous chemical leakage accident emergency evacuation path selection method

Abstract

The application discloses a kind of dangerous chemical leakage accident emergency evacuation path selection method, comprising the following steps: step one, according to the actual situation of plant road distribution, constructs plant road network;Step two, for sudden leakage accident of dangerous chemical, the concentration distribution of toxic gas at the scene of accident is calculated and influence area is divided;Step three, the average concentration value of toxic gas on the road section in different concentration range is calculated;Step four, according to the average concentration value of toxic gas on each road section, the time of evacuation crowd passing through each road section is combined, the toxic load of path formed by each road section is solved;Step five, according to the toxic load of path, evacuation model is constructed;Step six, evacuation model is solved.The method disclosed by the application can effectively reduce the harm of toxic gas to evacuation personnel in the process of evacuation by solving the optimal evacuation path, and has good application prospect in the field of dangerous chemical production and storage and transportation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of petrochemical safety, and particularly relates to a method for selecting an emergency evacuation path in a dangerous chemical leakage accident. BACKGROUND

[0002] In recent years, with the rapid development of the economic society, chemical production devices and storage facilities are developing in the trend of large-scale, intensive and integration, and the production and storage devices and facilities of dangerous chemicals with high energy and high toxicity are increasing year by year, the safety hidden danger is increasing year by year, and the major dangerous chemical accidents occur from time to time, which brings serious challenges to life and property. When a dangerous chemical leakage accident occurs, it is often not possible to monitor the toxic and harmful gases in the scene in all directions, and the harmful gases diffuse in the air. If the concentration exceeds a certain concentration and lasts for a certain period of time, it may be dangerous to cause disease, disability or even death to the on-site staff. The harm to personnel in a certain concentration of toxic gas environment will be different due to the toxicity and concentration of the gas, the contact time and the individual health quality of the personnel, and moreover, with the change of related factors such as leakage time, surrounding environment and meteorological conditions, the influence range of the toxic gas diffusion is also changing at any time. Therefore, the influence of harmful gases on the evacuation path must be considered during the evacuation process, and the harm partition in which the evacuation section is located must be dynamically determined.

[0003] Under normal circumstances, the time for evacuation is undoubtedly the main consideration factor in the evacuation process. If the evacuation personnel can reach the designated evacuation assembly point in the shortest time through the selected path, the purpose of this evacuation will be achieved. However, in the environment of toxic gas leakage, one factor cannot be ignored, that is, the influence of toxic gas on the life and health endurance of personnel on the evacuation section in the influence range. At this time, selecting a best path with the least harm will be more in line with the purpose of selecting the evacuation path. Therefore, on the basis of accident simulation and reference to experimental data, the concentration range of toxic gas in which the evacuation section is located can be dynamically determined, and the influence of road conditions on evacuation is considered, and then an actual emergency evacuation model under the condition of dangerous chemical leakage is given, and the k best evacuation paths of the evacuation model are solved, which can provide important guarantee for the life safety and physical health of personnel in the affected area in critical moments.

[0004] The patent CN109141423B provides a kind of evacuation path navigation system based on toxic gas diffusion influence, it includes toxic gas leakage data acquisition terminal, toxic gas diffusion simulation calculation module, evacuation path solving module, path navigation terminal and information transmission module.Toxic gas leakage data acquisition terminal will be collected to the toxic gas related data transmission to toxic gas diffusion simulation calculation module for solving, determine the optimal evacuation path from the collection point to the placement point, and send to path navigation display terminal, to assist crowd evacuation.Toxic gas is collected by acquisition terminal, and the coverage area is limited, so that part of the toxic area is excluded.

[0005] The patent CN106792894B needs to install wireless sensor nodes on the safety exit door of the petrochemical plant, and several static nodes are arranged inside the petrochemical plant.The field staff are defined as mobile nodes.When toxic gas leaks, the wireless sensor nodes send signal packets to the neighbor nodes within the communication range.The neighbor nodes that receive the information packets broadcast the received information packets and their own information packets to the neighbor nodes within their communication range.The field staff can determine the toxic gas concentration and the distance from the safety exit door according to the received information packets and take evacuation measures.The invention uses static nodes and mobile nodes to maintain the connectivity of the entire sensor network, which requires the installation of a large number of static wireless sensors and also relies on the mobile sensors worn by the field staff, making it difficult to implement and limiting the types of monitored gases, which cannot meet the actual needs. SUMMARY

[0006] To solve the above technical problems, the present application provides a hazardous chemical leakage accident emergency evacuation path selection method to effectively reduce the harm of toxic gas to evacuees during the evacuation process.

[0007] To achieve the above purpose, the technical solution of the present application is as follows:

[0008] A hazardous chemical leakage accident emergency evacuation path selection method includes the following steps:

[0009] Step one, according to the actual situation of factory road distribution, build factory road network;

[0010] Step two, for sudden leakage accident of hazardous chemicals, calculate the concentration distribution of toxic gas at the accident site and divide it into zones;

[0011] Step three, calculate the average concentration value of toxic gas on the road section falling into different concentration ranges;

[0012] Step four, according to the average concentration value of toxic gas on each road section, combined with the time of evacuation crowd passing through each road section, solve the toxic load of the path composed of each road section;

[0013] Step 5: Construct an evacuation model based on the toxic load of the path;

[0014] Step 6: Solve the evacuation model.

[0015] The specific method for step one of the above scheme is as follows:

[0016] Based on the actual distribution of roads within the factory area, a road network N = G(V, E, W) is constructed, where V = (v1, v2, ..., v...). n Let N be a finite set of nodes, used to represent the set of intersections in the road network, with finite arcs. It is an edge set;

[0017] Path e ij ∈E is node v i With v j The edge between two intersections represents the road between two intersections in the road network; W = (w ij ) n×n Let be the weight set of the edge set, and have

[0018]

[0019] The specific method for step two in the above scheme is as follows:

[0020] For sudden leaks of toxic and hazardous chemicals, a SLAB model is used to calculate the concentration of toxic gases at the incident site, and the boundary concentrations c1, c2, and c3 are set according to standards. For concentration c1, at a certain time t, the coordinate (x, y) starts increasing from the point (0, 0), i.e., x0 = 0, y0 = 0. The step sizes in the x and y directions are set as Δx and Δy, respectively. After determining x1, y is incremented, i.e., y1 = y0 + Δy. If the concentration c at (x1, y1) is greater than c1, then... If c < c1, then y2 = y1 + Δy; if the concentration c of (x1, y2) > C1, If c < c1, then y3 = y2 + Δy; continue the above steps to finally obtain y. k , (x1, y k Concentration c at point ) 1k Satisfy |c1-c 1k |<ε, where ε is the set error, and at this time (x1, y k This is a point on the boundary profile of c1. By analogy, the coordinate points on the boundary profiles of c1, c2, and c3 are determined. Three concentration profiles are drawn on the road network to obtain the leakage diffusion impact zone.

[0021] The specific method for step three in the above scheme is as follows:

[0022] An overlay analysis is performed on the road network obtained in step one and the leakage diffusion impact area obtained in step two to calculate e.ij The length d of the section e falling into the range of the three different concentrations obtained in step two ijk ijk , k = 1, 2, 3, let d ij1 be the length of the section e ij in the range of c1; the average concentration c ijk at e ijk at a certain time is calculated on the basis of the concentration of the coordinate points calculated in step two, and the method is as follows:

[0023] Uniformly select p points on e ijk , if the coordinate (x, y, z) of one of the points has no concentration value, then take (x, y, z) as the center and r as the radius to obtain m sampling points with concentration values in the specified range, then the concentration of the toxic gas at the coordinate (x, y) at a certain time t is:

[0024]

[0025] Where w i is the contribution coefficient of the sampling point (x i , y i , z i ), and 1≤i≤m;

[0026] Bring the sampling point (x i , y i , z i ) into the above formula to calculate w i and the values of the constant terms a, b, c, and d, and then obtain the concentration value at the coordinate (x, y, z);

[0027] Let the concentration of one of the above p points be c' h , 1≤h≤p, then the average concentration of e ijk is

[0028] In the above scheme, the specific method of step four is as follows:

[0029] The moving speed of the evacuating crowd on the path e ijk is represented by v ijk = v0·β ij ·f(c ijk ), where v0 is the normal walking speed; f(c ijk ) = 1 - q·(a + b·c ijk )·c ijk ·t ijk represents the influence factor of the toxic gas environment with concentration c ijk on the walking speed of the evacuating crowd, where a = 0.2125, b = 1.788, t​ijk To evacuate people through e ijk The time, and c ijk ≤c1 when q = 0, c1 ijk ≤c3 when q = 1, in particular, c ijk ≥c3 when f(c ijk ) = 0; σ is the road condition attenuation coefficient, σ ij is the road condition influence factor of e ij , σ ij <1, β ij The smaller, the worse the road condition;

[0030] The time for evacuating people through the road segment e ijk is:

[0031]

[0032] The value of t ijk can be obtained from the above equation, and the toxic load of the road segment e ijk is:

[0033] TL ijk = βc ijk γ t ijk θ

[0034] Wherein, β≤1 is the correlation coefficient; γ, θ are the correction coefficients of concentration and contact time on TL respectively;

[0035] The toxic load of the path e ij is

[0036] In the above scheme, the specific method of step five is as follows:

[0037] Define x ij ∈{0,1} as the decision variable

[0038]

[0039] According to the above definition, the mathematical model of the evacuation path in the toxic gas environment is established as follows:

[0040]

[0041]

[0042] Here, s, t represent the subscripts of the evacuation starting node and the target node respectively.

[0043] In the above scheme, the specific method of step six is as follows:

[0044] The double cleaning algorithm is used to solve k shortest paths between the start node and the end node meeting the conditions.

[0045] By the technical scheme, the hazardous chemical leakage accident emergency evacuation path selection method has the following beneficial effects:

[0046] The application establishes a toxic gas concentration partition calculation method for a leakage accident site based on a plant road network, calculates average concentration values of toxic gas at different time points on road segments falling into different concentration ranges according to the method, gives a toxic load dynamic calculation method for the path, and finally establishes a hazardous chemical leakage accident dynamic emergency evacuation model, so that the optimal evacuation path is obtained by solving the evacuation model, and the harm of toxic gas to evacuees in the evacuation process is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description.

[0048] Figure 1 A flowchart of the hazardous chemical leakage accident emergency evacuation path selection method disclosed by the embodiments of the application. DETAILED DESCRIPTION

[0049] The technical solutions in the embodiments of the application will be described clearly and completely in combination with the drawings in the embodiments of the application.

[0050] The application provides a hazardous chemical leakage accident emergency evacuation path selection method, and the specific embodiments are as follows:

[0051] Step 1: constructing a plant road network according to the actual situation of plant road distribution;

[0052] The plant road network N=G(V, E, W) is constructed according to the actual situation of plant road distribution, wherein V=(v1, v2,..., vN) is a finite node set of N, used to represent a road intersection set in the road network, and finite arc set E=(e1, e2,..., eM) is an edge set. n

[0053] The path e ij ∈E is an edge between the nodes v i and v j , representing a road between two road intersections in the road network; W=(w1, w2,..., wM) is a weight set of the edge set, and has w ij n×n

[0054]

[0055] ​​​​Step two, for the sudden leakage accident of dangerous chemicals, the concentration distribution of toxic gas at the accident site is calculated and the affected area is divided;

[0056] For the sudden leakage accident of toxic dangerous chemicals, the type of leakage source, the physical properties of leakage source, the overflow parameters, the field parameters, the environmental parameters, and the numerical step parameters are used to calculate the partition boundary concentration.

[0057] The concentration formula of toxic gas at a certain point in the downwind direction or wind direction of the leakage source is as follows:

[0058]

[0059] Where x is the downwind distance, y is the horizontal distance in the wind direction, z is the specified height, t is the leakage time, cc(x), xc(t), bx(t), betax(t), b(x), zc(x), sig(x) can be obtained in advance by the gas diffusion model SLAB,

[0060]

[0061] For a certain toxic gas, refer to the ERPG-1, ERPG-2, ERPG-3 values given in the "Emergency Response Plan Guide" formulated by the American Industrial Health Association to set the regional boundary concentration c1, c2, c3. For concentration c1, the coordinates (x, y) at time t start from (0, 0) point, i.e. x0=0, y0=0; Set the step length in x and y directions as Δx and Δy respectively, determine x1 and then increase y, i.e. y1=y0+Δy, if the concentration c of (x1, y1) is greater than c1, If c < c1, then y2=y1+Δy; if the concentration c of (x1, y2) is greater than c1, If c < c1, then y3=y2+Δy; continue the above steps to finally obtain y k , the concentration c k of (x1, y 1k ) satisfies |c1-c 1k | < ε, ε is the set error, and (x1, y k ) at this time is a point on the c1 boundary contour.

[0062] In this way, all points on the c1 boundary contour are obtained, assuming that m concentration values at coordinate points are obtained during the calculation process, and the concentration values of each coordinate point at different times are recorded as (x p1i , y p1i , t p1i , c p1i), i = 1, 2, …, m. Similarly, the coordinate points on the boundary profile of c2, c3 are obtained, and each coordinate point and its concentration value obtained in the solving process are recorded as (x p2j , y p2j , t p2j , c p2j ), j = 1, 2, …, l; (x p3k , y p3k , t p3k , c p3k ), k = 1, 2, …, s. Three concentration profiles are drawn on the road network to obtain the subareas of the leakage diffusion influence area.

[0063] Step three, calculating the average concentration of toxic gas on the road segment falling within different concentration ranges of the road network;

[0064] Superimposing the road network obtained in step one and the leakage diffusion influence area obtained in step two, the length d ij of the road segment e ijk falling within the three different concentration influence ranges obtained in step two is calculated, d ijk , k = 1, 2, 3, let d ij1 be the length of the segment e ij located within the c1 range; the average concentration c ijk on e ijk at a certain moment is calculated based on the concentration of the coordinate points calculated in step two, and the method is as follows:

[0065] Uniformly selecting p points on e ijk , if the coordinate (x, y, z) of a certain point has no concentration value, then taking (x, y, z) as the center and r as the radius, m sampling points with concentration values within the specified range are obtained, and the concentration of toxic gas at the coordinate (x, y, z) is:

[0066]

[0067] where w i is the contribution coefficient of the sampling point (x i , y i , z i ), and

[0068] The sampling point (x i , y i , z i ) is brought into the above formula to calculate w i and the values of the constant terms a, b, c, and d, and then the concentration value at the coordinate (x, y, z) is obtained;

[0069] Let the concentration of a certain point in the above p points be c′h , 1≤h≤p, then e ijk is the average concentration of toxic gas on the path e

[0070] Step four, according to the average concentration of toxic gas on each road segment, combined with the time of evacuees passing through each road segment, the toxic load of the path composed of each road segment is solved;

[0071] The moving speed of evacuees on the path e ijk is represented by v ijk =v0·β ij ·f(c ijk ), wherein v0 is the normal walking speed; f(c ijk )=1-q·(a+b·c ijk )·c ijk ·t ijk represents the influence factor of the toxic gas environment with the concentration value c ijk on the walking speed of evacuees, wherein a=0.2125, b=1.788, t ijk is the time of evacuees passing through e ijk , and q=0 when c ijk ≤c1, q=1 when c1 ijk <c3, and f(c ijk )=0 when c ijk ≥c3, in particular; is the road condition attenuation coefficient, σ ij is the road condition influence factor of e ij , σ ij <1, and the smaller β ij is, the worse the road condition is;

[0072] The time of evacuees passing through the road segment e ijk is:

[0073]

[0074] The value of t ijk can be obtained from the above equation, and the toxic load of the road segment e ijk is:

[0075] TL ijk =βc ijk γ t ijk θ

[0076] Wherein β≤1 is the correlation coefficient; γ, θ are the correction coefficients of concentration and contact time on TL respectively;

[0077] The toxic load of the path e ij is

[0078] Step five, evacuation model is constructed according to the toxic load of the path;

[0079] Define x ij ∈{0,1} is a decision variable

[0080]

[0081] According to the above definition, the mathematical model of evacuation path in toxic gas environment is established as follows:

[0082]

[0083]

[0084] Here, s, t respectively represent the subscripts of the evacuation starting node and the target node.

[0085] Step six, the evacuation model is solved.

[0086] According to the actual problem, in addition to calculating an optimal path, it is also necessary to solve the second best path or the third best path, or even more, and to sort out the priority order, so that the decision maker can choose in an emergency, thereby improving the safety of personnel in the evacuation process. According to the definition of the evacuation model, solving the problem of k optimal paths is converted to solving the problem of k shortest paths. The double sweep algorithm is used to solve the k shortest paths between the starting node and the terminal node.

[0087] The above description of disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for selecting emergency evacuation routes in a hazardous chemical spill accident, characterized in that, Includes the following steps: Step 1: Construct the factory road network according to the actual distribution of roads in the factory area; Step 2: For sudden leaks of hazardous chemicals, calculate the concentration distribution of toxic gases at the accident site and delineate the affected areas; Step 3: Calculate the average concentration of toxic gases on road sections within different concentration ranges of the road network; Step 4: Based on the average concentration of toxic gases on each road segment and the time it takes for evacuated people to pass through each road segment, calculate the toxic load of the path formed by each road segment. Step 5: Construct an evacuation model based on the toxic load of the path; Step 6: Solve the evacuation model; The specific method for step two is as follows: In response to sudden leaks of toxic and hazardous chemicals, the SLAB model is used to calculate the concentration of toxic gases at the incident site, and the boundary concentrations of different zones are set with reference to standards. Regarding concentration The coordinate of t at a certain time from Starting from the point, incrementing, that is ;set up , The step sizes in the directions are respectively , ,Sure Later Increasing, that is ,if concentration ,but ,if ,but ;if concentration , ,if ,but ; Continue the above steps to finally obtain , Concentration at point , To set the error, at this time That is One point on the boundary profile, and so on, to complete. Determining the coordinate points of the boundary profile leads to the zoning of the leakage diffusion impact area; The specific method for step three is as follows: An overlay analysis is performed on the road network obtained in step one and the leakage diffusion impact zones obtained in step two to calculate... Road sections falling within the three different concentration influence ranges obtained in step two length , ,make for lie in The segment length within the range; the concentration at a certain moment calculated based on the coordinate point obtained in step two. average concentration The method is as follows: exist Selecting uniformly from above Given a point, if one of its coordinates... If no concentration value is found at that location, then use... Using r as the center and r as the radius, obtain the concentration values ​​within a specified range. If there are 1 sampling point, then the coordinates are... The concentration of toxic gas at the location is: ； in, For sampling points ( The contribution coefficient of ) and , ; Sampling points ( Substitute into the above formula and calculate. and constant term The value of is then used to obtain the coordinates. Concentration value at; The above The concentration at a certain point among the points is ,but average concentration ; The specific method for step four is as follows: Evacuation of people along the route The movement speed on the top It means that, among them, This is a normal walking speed; The concentration value indicates Factors influencing the walking speed of evacuated crowds in toxic gas environments, among which , , In order to evacuate the crowd Time, and hour, , hour, In particular, hour, ; This is the road condition attenuation coefficient. for Road condition influencing factors , The smaller the value, the worse the road conditions. Evacuation route time for: ， From the above equation, we can obtain The value of , then the road segment The toxic load is: ； in, The correlation coefficient; Concentration and contact time, respectively Correction factor for contribution; Then the path The toxic load is .

2. The method for selecting emergency evacuation routes in a hazardous chemical spill accident according to claim 1, characterized in that, The specific method for step one is as follows: Construct a road network for the factory area based on the actual distribution of roads within the factory area. ,in, for A finite set of nodes is used to represent the set of intersections in a road network, and a finite set of arcs. It is an edge set; path For nodes The edges between them represent the roads between two intersections in the road network; Let be the weight set of the edge set, and have 。 3. The method for selecting emergency evacuation routes in a hazardous chemical spill accident according to claim 1, characterized in that, The specific method for step five is as follows: definition Decision variables ； Based on the above definition, the mathematical model for evacuation routes in a toxic gas environment is established as follows: ； ； here, These represent the indices of the starting and target nodes of the evacuation, respectively.

4. The method for selecting emergency evacuation routes in a hazardous chemical spill accident according to claim 1, characterized in that, The specific method for step six is ​​as follows: The double-sweep algorithm is used to find the nodes that meet the conditions between the start and end nodes. The shortest path.

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