A safety distance determination method based on liquid ethane pipeline leakage accident

Abstract

The embodiment of the application provides a safety distance determination method based on a liquid ethane pipeline leakage accident, which can solve the technical problem of poor flexibility of liquid ethane pipeline safety distance setting. The method comprises the following steps: obtaining the leakage rate and combustible gas mass of the liquid ethane pipeline under different leakage aperture conditions according to finite element calculation; determining the effective leakage source diameter according to the leakage rate; determining the jet fire length and jet fire surface area according to the effective leakage source diameter; determining the combustion heat according to the jet fire length and jet fire surface area; determining the surface emissivity according to the combustion heat; determining the thermal radiation value on the preset distance according to the surface emissivity; determining the combustible gas equivalent and explosion total energy according to the combustible gas mass; determining the positive maximum overpressure and shock wave positive impulse according to the explosion total energy and combustible gas equivalent; and determining the safety distance according to the thermal radiation value, the positive maximum overpressure and the shock wave positive impulse.

Description

Technical Field

[0001] This application relates to the field of long-distance pipeline technology, and in particular to a method for determining the safe distance based on a liquid ethane pipeline leakage accident. Background Technology

[0002] Ethane pipelines are used to transport ethane, including gaseous ethane (NGL) pipelines and liquid or dense-phase ethane (NGL) pipelines. Gaseous ethane pipelines have lower transport pressures and smaller flow rates, and relatively lower requirements for pipe material performance, but are less economical. Liquid / dense-phase ethane pipelines typically have higher transport pressures and larger flow rates, and are more economical. However, ruptures due to corrosion or other reasons can lead to flammable gas leaks, explosions, and combustion—catastrophic accidents that can result from the gas's diffusion in the air. Therefore, compared to gaseous ethane pipelines, to ensure the normal operation of liquid or dense-phase ethane pipelines, it is extremely important to study the risk assessment of accidents involving liquid ethane pipelines, analyze and predict potential hazards in advance, and establish safe distances.

[0003] Currently, based on safety standards set by industry researchers, and taking into account factors such as the actual terrain, population density, and environmental sensitivity along the pipeline route, corresponding parameters are selected to ultimately obtain a fixed safe distance value. For example, the minimum distance range for liquid ethane pipelines is 15 to 50 meters.

[0004] However, fixed safety distance values ​​may not fully adapt to actual geographical and environmental conditions, lacking flexibility for specific risk scenarios. Therefore, how to flexibly set the safety distance for liquid ethane pipelines has become an urgent problem to be solved. Summary of the Invention

[0005] This application provides a method for determining the safe distance based on a liquid ethane pipeline leakage accident, which can solve the technical problem of poor flexibility in setting the safe distance for liquid ethane pipelines.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0007] In a first aspect, embodiments of this application provide a method for determining a safe distance based on a liquid ethane pipeline leakage accident. This method includes: obtaining the leakage rate and combustible gas mass of the liquid ethane pipeline under different leakage orifice diameters using finite element analysis; determining the effective leakage source diameter based on the leakage rate; determining the jet flame length and jet flame surface area based on the effective leakage source diameter; determining the combustion heat based on the jet flame length and jet flame surface area; determining the surface emissivity based on the combustion heat; determining the thermal radiation value at a preset distance based on the surface emissivity; determining the combustible gas equivalent and total explosion energy based on the combustible gas mass; determining the maximum overpressure and the forward impulse of the shock wave based on the total explosion energy and the combustible gas equivalent; and determining the safe distance based on the thermal radiation value, the maximum overpressure, and the forward impulse of the shock wave.

[0008] Based on the above description of the method for determining safe distances in the context of liquid ethane pipeline leaks provided in this application, it can be seen that this method includes determining the leakage rate and mass of combustible gas through finite element simulation, and further calculating the impact range of possible jet fire and vapor cloud explosion accidents. This rapidly determines the safe design distance between critical instruments and pipelines, as well as the safe distance for rescue personnel after an accident, providing analytical and predictive means and reference for avoiding accidents and disasters caused by ethane pipeline leaks. In this way, it is possible to analyze and predict accidents and disasters in advance, and set safe distances, providing analytical and predictive means and reference for avoiding accidents and disasters caused by ethane pipeline leaks.

[0009] In the feasible implementation of the first aspect, the formula for calculating the effective leakage source diameter includes:

[0010] D s =[4*Q / (π*ρ)] a *u j )] 1 / 2 ;

[0011] Where Q represents the leakage rate, in units of kg / s; ρ a Expressed as air density, unit is kg / m³ 3 ; indicates the gas velocity at the leak hole, in m / s.

[0012] In the feasible implementation of the first aspect, the formula for calculating the leakage rate includes:

[0013] u j =M j *(k*8.314*T j / W g ) 1 / 2 ;

[0014] Among them, M j Expressed as the Mach number for gas leakage; W g T is expressed as the molar mass of the leaked substance, in kg / mol. j The temperature before the gas leak hole expands is expressed in K; k represents the isentropic exponent of the gas.

[0015] In the feasible implementation of the first aspect, the formula for calculating the length of the jet flame includes:

[0016]

[0017] Among them, L b L represents the flame length under windy conditions. bo L represents the length of a flame at rest in the air. b0 =Y×D s Y represents the first auxiliary variable; u w The wind speed is expressed in m / s; θ represents the angle between the orifice axis and the horizontal plane, with a value ranging from 0° to 90°.

[0018] In the feasible implementation of the first aspect, the formula for calculating the surface area of ​​the jet flame includes:

[0019]

[0020] Where A represents the surface area of ​​the jet flame; W1 represents the width at the base of the flame; W2 represents the width at the tip of the flame; and R1 represents the length of the flame cone. This is expressed as the flame tilt angle.

[0021] In the feasible implementation of the first aspect, the formula for calculating the thermal radiation value includes:

[0022]

[0023] Where I(r) represents the thermal radiation intensity, with units of kW / m². 2 ;T jet Represented as emissivity coefficient; η represents efficiency factor; r represents the distance from the leak to the target point of thermal radiation, in meters; H c R1 represents the heat of combustion of the combustible gas, expressed in J / kg; Q represents the length of the flame cone; and Q represents the leakage rate.

[0024] In the feasible implementation of the first aspect, the formula for calculating the maximum overpressure in the positive phase includes:

[0025]

[0026] Among them, Ps R' represents the maximum overpressure in the positive phase of the shock wave; P represents the dimensionless distance; R′ represents the maximum overpressure in the positive phase of the shock wave; P represents the maximum overpressure in the positive phase of the shock wave. a The pressure is expressed as atmospheric pressure, Pa; R represents the distance from the target to the center of the vapor cloud, in meters.

[0027] In the feasible implementation of the first aspect, the formula for calculating the positive impulse of the shock wave includes:

[0028]

[0029] Among them, i s R represents the positive impulse of the shock wave; R′ represents the dimensionless distance; and E represents the heat of combustion.

[0030] Secondly, embodiments of this application provide a safety distance determination system based on a liquid ethane pipeline leak accident. The safety distance determination system based on a liquid ethane pipeline leak accident includes: at least one processor; a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method provided in the first aspect.

[0031] The system for determining safe distances in ethane pipeline leak accidents, based on the method provided in the first aspect, uses finite element simulation to determine the leakage rate and mass of combustible gas. It further calculates the impact range of potential jet fires and vapor cloud explosions, rapidly determining the safe design distances between critical instruments and pipelines, as well as the safe distances for rescue personnel after an accident. This provides analytical and predictive tools and references for preventing accidents and disasters caused by ethane pipeline leaks. In this way, it enables early analysis and prediction of accident disasters, setting safe distances, and providing analytical and predictive tools and references for preventing accidents and disasters caused by ethane pipeline leaks.

[0032] Thirdly, embodiments of this application provide a computer-readable medium having computer program instructions stored thereon, which can be executed by a processor to implement the method provided in the first aspect.

[0033] The computer program instructions in the computer-readable medium, by implementing the method provided in the first aspect, determine the leakage rate and mass of combustible gas in the event of a gas leak through finite element simulation. Furthermore, they calculate the impact range of potential jet fire and vapor cloud explosion accidents, rapidly determining the safe design distance between critical instruments and pipelines, as well as the safe distance for rescue personnel after an accident. This provides analytical and predictive means and reference for avoiding accidents and disasters caused by ethane pipeline leaks. In this way, accident and disaster analysis and prediction can be performed in advance, and safe distances can be set, providing analytical and predictive means and reference for avoiding accidents and disasters caused by ethane pipeline leaks. Attached Figure Description

[0034] Figure 1 A schematic diagram of a safety distance determination system based on a liquid ethane pipeline leakage accident is provided in this application embodiment;

[0035] Figure 2 A flowchart illustrating a method for determining a safe distance based on a liquid ethane pipeline leakage accident, provided as an embodiment of this application;

[0036] Figure 3 This is a schematic diagram illustrating one implementation of a three-dimensional model of a liquid ethane pipeline in a method for determining a safe distance in a liquid ethane pipeline leakage accident, as provided in an embodiment of this application. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the embodiments of the present invention, unless otherwise stated, "multiple" refers to two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be single or multiple.

[0038] Furthermore, to facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with substantially the same function and effect. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that "first" and "second" are not necessarily different. Meanwhile, in the embodiments of the present invention, the terms "exemplary" or "for example" are used to indicate that something is being used as an example, illustration, or description. Any embodiment or design scheme described as "exemplary" or "for example" in the embodiments of the present invention should not be construed as being more preferred or advantageous than other embodiments or design schemes. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner for ease of understanding.

[0039] The principles and features of this application are described below. The examples given are only for explaining this application and are not intended to limit the scope of this application.

[0040] Ethane is a primary product of cryogenic natural gas plants. Ethane needs to be transported under high pressure to maintain its liquid or gaseous state, reduce its volume, and improve transportation efficiency. Therefore, long-distance pipeline systems specifically designed for transporting ethane have become a crucial part of the ethane industry.

[0041] Pipeline systems, typically including compressor stations, pumping stations, pressure regulating equipment, and storage facilities, ensure safe transport of ethane. Pipeline transport of ethane is more economical than rail or road transport and is suitable for long-distance, large-scale transport. Compared to other modes of transport, pipeline transport reduces the risk of accidents such as leaks and fires, and also reduces carbon emissions and environmental pollution during transport.

[0042] To achieve safe management of pipeline systems, it is necessary to monitor pressure, temperature, and flow rate to prevent leaks or explosions. This application provides a method for determining safe distances in the event of a liquid ethane pipeline leak, applicable to various liquid ethane transportation scenarios. This application uses finite element simulation to determine the leakage rate and mass of combustible gas in the event of a leak, and further calculates the impact range of potential jet fire and vapor cloud explosion accidents. It quickly determines the safe design distance between critical instruments and pipelines, as well as the safe distance for emergency response personnel after an accident, providing analytical and predictive tools and references for preventing accidents and disasters caused by ethane pipeline leaks. This allows for early analysis and prediction of potential accidents and disasters, and the establishment of safe distances, providing analytical and predictive tools and references for preventing accidents and disasters caused by ethane pipeline leaks.

[0043] This application provides a system for determining safe distances based on liquid ethane pipeline leaks, which can execute the method for determining safe distances based on liquid ethane pipeline leaks provided in this application. Figure 1 This is a schematic diagram of a system for determining a safe distance in the event of a liquid ethane pipeline leak, provided as an embodiment of this application.

[0044] like Figure 1 As shown, the safety distance determination system 001 based on a liquid ethane pipeline leak accident includes at least one processor 011 and a memory 012 communicatively connected to the at least one processor; wherein, the memory 012 stores instructions that can be executed by the at least one processor 011, and the instructions are executed by the at least one processor 011 to enable the at least one processor 011 to execute the safety distance determination method based on a liquid ethane pipeline leak accident provided in the embodiments of this application.

[0045] Figure 2 This is a flowchart illustrating a method for determining a safe distance in the event of a liquid ethane pipeline leak, as provided in an embodiment of this application. Figure 2 As shown, in some embodiments, the method for determining the safe distance based on a liquid ethane pipeline leak includes the following steps:

[0046] S1, based on finite element calculations, yields the leakage rate and combustible gas mass of the liquid ethane pipeline under different leakage orifice diameters.

[0047] In some embodiments, a three-dimensional model of the liquid ethane pipeline is established using FLACS software. Finite element simulations of the accident consequences under different leakage orifice diameters are performed using FLACS software to obtain the leakage rate and the mass of combustible gas in the vapor cloud under different leakage orifice diameter conditions.

[0048] For example, such as Figure 3 As shown, the liquid ethane pipeline is 36.6m long and 323.9mm in diameter. L1 represents a leak orifice diameter of 15mm. L2 represents a leak orifice diameter of 5mm. L3 represents a leak orifice diameter of 25mm. L4 represents a leak orifice diameter of 10mm. Multiple monitoring points were selected at intervals along different sampling lines to obtain simulated accident consequences for this liquid ethane pipeline under different leak orifice diameters. For example, as... Figure 3 The three sampling lines shown each have eight monitoring points selected on them.

[0049] Utilize Figure 3 The FLACS software shown simulates the accident consequences for different leakage orifice diameters, and obtains the leakage rate and the mass of combustible gas in the vapor cloud under different leakage orifice diameter conditions, as shown in Table 1.

[0050] Table 1 Ethane Leakage Rate and Combustible Gas Mass

[0051] aperture 5mm 10mm 15mm 25mm Leakage rate kg / s 0.56969 2.2554 5.0611 14.059 Combustible gas mass (kg) 0.4 1.6 11.4 48.5

[0052] In some embodiments, the formula for calculating the leakage rate includes:

[0053] u j =M j *(k*8.314*T j / W g ) 1 / 2 ;

[0054] Among them, M j Expressed as the Mach number for gas leakage; W g T is expressed as the molar mass of the leaked substance, in kg / mol. j The temperature before the gas leak hole expands is expressed in K; k represents the isentropic exponent of the gas.

[0055] It should be noted that the molar mass of ethane is 0.03007 kg / mol.

[0056] S2, determine the effective leakage source diameter based on the leakage rate.

[0057] In some embodiments, the formula for calculating the effective leakage source diameter includes:

[0058] D s =[4*Q / (π*ρ)] a *u j )] 1 / 2 ;

[0059] Where Q represents the leakage rate, with units of kg / s; ρ a Expressed as air density, unit is kg / m³ 3 ;

[0060] u j This represents the gas flow velocity at the leak hole, expressed in m / s.

[0061] The formulas for calculating the gas velocity at the leak orifice include:

[0062] u j =M j *(k*8.314*T j / W g ) 1 / 2 ;

[0063] The formulas for calculating the Mach number of a gas leak include:

[0064]

[0065] The formulas for calculating the static pressure at the leak orifice include:

[0066] P c =P init*(2 / (k+1)) [k / (k-1)] ;

[0067] Among them, P init This represents the initial pressure in the pipeline, expressed in Pa.

[0068] The formulas for calculating the temperature before the gas leak hole expands include:

[0069] T j =T s *((P a / P init ) [k / (k-1)] ;

[0070] Among them, T s The initial temperature of the gas is expressed in Kelvin (K).

[0071] S3, determine the length and surface area of ​​the jet flame based on the effective leakage source diameter.

[0072] In some embodiments, the formula for calculating the length of the jet flame includes:

[0073]

[0074] Among them, L b L represents the flame length under windy conditions. bo L represents the length of a flame at rest in the air. b0 =Y×D s Y represents the first auxiliary variable; u w The wind speed is expressed in m / s; θ represents the angle between the orifice axis and the horizontal plane, with a value ranging from 0° to 90°.

[0075] The formula for calculating the first auxiliary variable Y includes:

[0076]

[0077] Where W represents the relative molecular mass of the leaked substance.

[0078] In some embodiments, the formula for calculating the surface area of ​​the jet flame includes:

[0079]

[0080] Where A represents the surface area of ​​the jet flame; W1 represents the width at the base of the flame; W2 represents the width at the tip of the flame; and R1 represents the length of the flame cone. α represents the flame tilt angle.

[0081] The formulas for calculating the flame tilt angle include:

[0082]

[0083] The formulas for calculating the Richardson number in still air around a flame include:

[0084]

[0085] The formulas for calculating the ratio of jet velocity to wind speed include:

[0086] R w =u j / u w ;

[0087] The formulas for calculating flame rise height include:

[0088]

[0089] The formulas for calculating the length of the flame cone include:

[0090]

[0091] The formulas for calculating the width of the flame's base and tip include:

[0092]

[0093] Among them, auxiliary variables

[0094] S4. Determine the combustion heat based on the length and surface area of ​​the jet flame.

[0095] In some embodiments, the formula for calculating the heat of combustion includes:

[0096] E = Q × H c ;

[0097] Where E represents the heat generated by combustion, in J; H c It is expressed as the heat of combustion of a combustible gas, and the unit is J / kg.

[0098] S5, determine the surface emissivity based on the heat of combustion.

[0099] In some embodiments, the formula for calculating surface emissivity includes:

[0100] SEP = F s ×E;

[0101] Where SEP represents surface emissivity; F s This represents the proportion of heat energy converted into surface radiation. E represents the heat generated by combustion, measured in J.

[0102] S6, determine the thermal radiation value at a preset distance based on the surface emissivity.

[0103] In some embodiments, the formula for calculating thermal radiation values ​​includes:

[0104]

[0105] Where I(r) represents the thermal radiation intensity, with units of kW / m². 2 ;T jet Represented as emissivity coefficient; η represents efficiency factor; r represents the distance from the leak to the target point of thermal radiation, in meters; H c R1 represents the heat of combustion of the combustible gas, expressed in J / kg; Q represents the length of the flame cone; and Q represents the leakage rate.

[0106] Understandably, the preset distance is the distance r from the leak point to the target point of thermal radiation.

[0107] In one implementation, T jet The value can be 0.2.

[0108] In one implementation, η can take the value 0.35.

[0109] S7. Determine the combustible gas equivalent and total explosion energy based on the mass of the combustible gas.

[0110] In some embodiments, the formula for calculating the combustible gas equivalent includes:

[0111]

[0112] Among them, H TNT The heat of explosion of trinitrotoluene (TNT) is expressed in J / kg; W TNT The TNT equivalent of the combustible gas is expressed in kg; W represents the mass of the combustible gas in the vapor cloud, in kg; H represents the heat of combustion of the combustible gas; and α represents the combustible gas vapor cloud equivalent coefficient.

[0113] In one implementation, H TNT The value can be 4500 kJ / kg.

[0114] In one implementation, the value of H can be 51795.57 kJ / kg.

[0115] In one implementation, α can take the value of 4%.

[0116] In some embodiments, the formula for calculating the total energy of the explosion includes:

[0117] E = 1.8αWH;

[0118] Where E represents the total explosion energy of the combustible gas, in J; 1.8 is the ground explosion coefficient.

[0119] S8. Based on the total explosion energy and the equivalent of combustible gas, determine the maximum overpressure and the positive impulse of the shock wave.

[0120] In some embodiments, the formula for calculating the maximum overpressure in the positive phase includes:

[0121]

[0122] Among them, P s R' represents the maximum overpressure in the positive phase of the shock wave; P represents the dimensionless distance; R′ represents the maximum overpressure in the positive phase of the shock wave; P represents the maximum overpressure in the positive phase of the shock wave. a The pressure is expressed as atmospheric pressure, Pa; R represents the distance from the target to the center of the vapor cloud, in meters.

[0123] In some embodiments, the formula for calculating the positive impulse of a shock wave includes:

[0124]

[0125] Among them, i s R represents the positive impulse of the shock wave; R′ represents the dimensionless distance; and E represents the heat of combustion.

[0126]

[0127] Among them, P s Represented as the maximum overpressure in the positive phase of the shock wave; i s R' represents the positive impulse of the shock wave; P represents the dimensionless distance; a R is expressed as atmospheric pressure, Pa; R is the distance from the target to the center of the vapor cloud, m.

[0128] S9. The safe distance is determined based on the thermal radiation value, the maximum overpressure in the positive phase, and the positive impulse of the shock wave.

[0129] For example, the losses caused by different thermal radiation fluxes are shown in Table 2.

[0130] Table 2 Criteria for Thermal Radiation Flux

[0131]

[0132] The unit of thermal radiation flux is kW / m². 2 .

[0133] For example, different regions have different standards for the threshold of explosive shock waves, and their harmful effects on outdoor and indoor personnel are different, as shown in Table 3.

[0134] Table 3. Harmful effects of shock waves on personnel under different environments.

[0135]

[0136]

[0137] The unit for explosive overpressure is MPa.

[0138] For example, this embodiment calculates the jet thermal radiation and vapor cloud explosion shock wave overpressure generated by accidents after leakage of different leakage orifice diameters, and summarizes the safe distance for personnel, as shown in Table 4:

[0139] Table 4. Impact range on outdoor personnel under different leakage conditions

[0140]

[0141] As can be seen from the above embodiments, this application can take into account the potential damage to surrounding personnel caused by jet fire and vapor cloud explosion accidents after the pipeline experiences small hole, large hole and full cross-section rupture leakage, as well as the determination of safe distances for personnel handling after the accident, when designing ethane pipelines. It is necessary to quickly calculate the range of heat radiation and vapor cloud explosion hazards generated by different leakage hole diameters in a short period of time, and provide a reference for the design and installation of ethane pipelines and the safe evacuation in the event of an accident.

[0142] Based on the same concept, this application also provides a system for determining a safe distance in the event of a liquid ethane pipeline leak. The method corresponding to this system can be the same as the method described in the foregoing embodiments, and its principle for solving the problem is similar. The system provided in this application includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, which, when executed, enable the at least one processor to perform the methods and / or technical solutions of the various embodiments of this application.

[0143] Another embodiment of this application provides a computer-readable storage medium having computer program instructions stored thereon, which can be executed by a processor to implement the methods and / or technical solutions of any one or more embodiments of this application described above.

[0144] Specifically, this embodiment may employ any combination of one or more computer-readable media. A computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium may be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media (a non-exhaustive list) include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus, or device.

[0145] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including—but not limited to—electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0146] The program code contained on a computer-readable medium may be transmitted using any suitable medium, including—but not limited to—wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0147] Computer program code for performing the operations of this application can be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, and C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code can be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In cases involving remote computers, the remote computer can be connected to the user's computer via any type of network—including a local area network (LAN) or a wide area network (WAN)—or can be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0148] The flowcharts or block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of devices, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-specific system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0149] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or page components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units through some interfaces, and may be electrical, mechanical, or other forms.

[0151] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0152] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0153] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0154] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

[0155] Furthermore, it is clear that the word "comprising" does not exclude other units or steps, and the singular does not exclude the plural. Multiple units or devices recited in a device claim may also be implemented by a single unit or device through software or hardware. The terms "first," "second," etc., are used to indicate names and do not indicate any specific order.

Claims

1. A method for determining a safe distance based on a liquid ethane pipeline leakage accident, characterized in that, include: Based on finite element analysis, the leakage rate and combustible gas mass of the liquid ethane pipeline under different leakage orifice diameters were obtained. Determine the effective leakage source diameter based on the leakage rate; The length and surface area of ​​the jet flame are determined based on the effective leakage source diameter. The heat of combustion is determined based on the length and surface area of ​​the jet flame. The surface emissivity is determined based on the combustion heat. Based on the surface emissivity, determine the thermal radiation value at the preset distance; Based on the mass of the combustible gas, determine the combustible gas equivalent and the total explosion energy; Based on the total explosion energy and the equivalent of the combustible gas, determine the maximum overpressure and the forward impulse of the shock wave. The safe distance is determined based on the thermal radiation value, the maximum positive overpressure, and the positive impulse of the shock wave.

2. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 1, characterized in that, The formula for calculating the effective leakage source diameter includes: D s =[4*Q / (π*ρ a *u j )] 1 / 2 ; Where Q represents the leakage rate, in units of kg / s; ρ a Expressed as air density, unit is kg / m³ 3 ;u j This represents the gas flow velocity at the leak hole, expressed in m / s.

3. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 1 or 2, characterized in that, The formula for calculating the leakage rate include: u j =M j *(k*8.314*T j / W g ) 1 / 2 ; Among them, M j Expressed as the Mach number for gas leakage; W g T is expressed as the molar mass of the leaked substance, in kg / mol. j The temperature before the gas leak hole expands is expressed in K; k represents the isentropic exponent of the gas.

4. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 1 or 2, characterized in that, The formula for calculating the length of the jet flame includes: Among them, L b L represents the flame length under windy conditions. bo L represents the length of a flame at rest in the air. b0 =T×D s Y represents the first auxiliary variable; u w The wind speed is expressed in m / s; θ represents the angle between the orifice axis and the horizontal plane, with a value ranging from 0° to 90°.

5. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 1 or 2, characterized in that, The formula for calculating the surface area of ​​the jet flame includes: Where A represents the surface area of ​​the jet flame; W1 represents the width at the base of the flame; W2 represents the width at the tip of the flame; and R1 represents the length of the flame cone. α represents the flame tilt angle.

6. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 1 or 2, characterized in that, The formula for calculating the thermal radiation value includes: Where I(r) represents the thermal radiation intensity, with units of kW / m². 2 ;T jet Represented as emissivity coefficient; η represents efficiency factor; r represents the distance from the leak to the target point of thermal radiation, in meters; H c R1 represents the heat of combustion of the combustible gas, expressed in J / kg; Q represents the length of the flame cone; and Q represents the leakage rate.

7. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 1 or 2, characterized in that, The formula for calculating the maximum overpressure in the positive phase includes: Among them, P s R' represents the maximum overpressure in the positive phase of the shock wave; P represents the dimensionless distance; R′ represents the maximum overpressure in the positive phase of the shock wave; P represents the maximum overpressure in the positive phase of the shock wave. a The pressure is expressed as atmospheric pressure, Pa; R represents the distance from the target to the center of the vapor cloud, in meters.

8. The method for determining the safe distance based on a liquid ethane pipeline leakage accident according to claim 7, characterized in that, The formula for calculating the positive impulse of the shock wave includes: Among them, i s R represents the positive impulse of the shock wave; R′ represents the dimensionless distance; and E represents the heat of combustion.

9. A system for determining safe distances based on liquid ethane pipeline leakage accidents, characterized in that, include: At least one processor; A memory that is communicatively connected to the at least one processor; The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method of any one of claims 1 to 8.

10. A computer-readable medium having stored thereon computer program instructions that can be executed by a processor to implement the method as described in any one of claims 1 to 8.

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