Hydrogen-doped natural gas pipeline transportation system virtual energy storage characteristic modeling method considering pipe storage

Abstract

The invention relates to a virtual energy storage characteristic modeling method for a hydrogen-doped natural gas pipeline transportation system considering pipe storage, and the method comprises the steps: S1, building a physical characteristic model of hydrogen-doped natural gas of a hydrogen transportation pipeline based on the physical properties of natural gas and hydrogen; s2, considering changes of characteristics such as pressure, permeation and attenuation of the system after hydrogen is doped into the natural gas pipeline, and considering a dynamic compression ratio to construct a compressor power consumption model, maintaining pressure balance of the hydrogen-doped natural gas pipeline, and establishing a dynamic operation characteristic model of the hydrogen-doped natural gas pipeline transportation system; s3, pipe storage is considered, a finite difference method is adopted to discretize the partial differential equation describing the flow process of the hydrogen-doped natural gas in time and space, and the operation constraint of the hydrogen-doped natural gas pipeline transportation system is constructed. According to the invention, the modeling efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage modeling, and in particular to a method for modeling virtual energy storage characteristics of a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration. Background Art

[0002] With the increase in the scale of new energy grid connection and the proportion of electricity, the long-term energy and power balance problem caused by the long-term low output of the main new energy power sources has become increasingly severe under extreme weather conditions of no wind and little light on a weekly to monthly scale. The advantages of large-capacity cross-seasonal energy storage in the form of hydrogen energy are highlighted, becoming an important and even the main effective solution to cope with the long-term energy and power supply balance.

[0003] The energy storage characteristics of green hydrogen play a major role in the consumption and supply balance of new energy in the interactive integration of electricity and hydrogen, and its mechanism of action includes two aspects. First, the use of electric hydrogen production combined with CCS carbon capture and storage technology, through the reaction of H2X hydrogen and carbon dioxide under the action of a catalyst, to generate renewable hydrogen-rich compounds synthesized in the green chemical product link has a high energy density. Renewable hydrogen-rich compounds that are easy to store and transport can be burned and connected to the grid to generate electricity when the power grid is insufficient, forming an electric-hydrogen-carbon cycle energy storage system, and forming a complementary long-term balance capacity mechanism with the energy storage function of the electric-hydrogen-(electric) cycle, thereby improving energy storage efficiency. The second is to use the time lag characteristics of hydrogen or its compounds in the process of transmission, storage, conversion and utilization to form an energy and power source-load matching buffer storage. In order to give full play to the buffering effect of the pipeline in the hydrogen transmission system, it is necessary to consider the structural characteristics of the pipeline and the dynamic parameter characteristics such as port pressure, gas source flow and flow rate to control the transmission rate, and to form a virtual energy storage characteristic of the hydrogen transmission process by establishing a pipeline negative feedback regulation mechanism.

[0004] The interactive fusion technology of electricity and hydrogen based on green hydrogen provides an effective way to develop new energy, but it faces the following challenges that need to be solved urgently: green hydrogen energy storage coupled with multiple scenarios of new energy power generation, power generation participating in new energy consumption and grid supply balance. The production system of green hydrogen transportation and physical form consumption of green hydrogen has a large time lag, providing buffering and redundancy for the system. Its power load and energy storage characteristics interact with each other, and the structure and feedback mechanism of comprehensive utilization of electricity and hydrogen are complex. Therefore, seeking to model the energy storage mechanism of electricity-hydrogen interaction is an important way to solve the urgent problems of new energy consumption and supply guarantee. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a virtual energy storage characteristic modeling method for a hydrogen-blended natural gas pipeline transportation system taking into account pipeline storage. Aiming at the buffering virtual energy storage in the hydrogen transmission link, the storage characteristics of the pipeline are combined with the characteristics of the transportation form of hydrogen energy. After hydrogen is blended into the natural gas pipeline, the changes in pressure, permeability, attenuation and other characteristics of the system are considered. The load changes are buffered by adjusting the working parameters such as pipeline pressure and temperature. Based on the finite difference method, a dynamic flow balance characteristic equation of hydrogen pipeline transportation is established, and a virtual energy storage model for pipeline hydrogen transmission is established.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: A virtual energy storage characteristic modeling method for a hydrogen-blended natural gas pipeline transportation system considering pipeline storage includes the following steps: Step S1: constructing a physical property model of hydrogen-blended natural gas in a hydrogen transmission pipeline based on the physical properties of natural gas and hydrogen; Step S2: Considering the changes in the system's pressure, permeation, attenuation and other characteristics after hydrogen is added to the natural gas pipeline, and taking into account the dynamic compression ratio to build a compressor power consumption model, maintain the pressure balance of the hydrogen-added natural gas pipeline, and establish a dynamic operation characteristic model of the hydrogen-added natural gas pipeline transportation system; Step S3: Considering the pipeline storage, the finite difference method is used to discretize the partial differential equations describing the flow process of hydrogen-blended natural gas in time and space, and the operation constraints of the hydrogen-blended natural gas pipeline transportation system are constructed.

[0007] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the steps of the method for modeling virtual energy storage characteristics of a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration are implemented.

[0008] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for modeling virtual energy storage characteristics of a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration.

[0009] Compared with the prior art, the present invention has the following beneficial effects: The traditional modeling of hydrogen-blended natural gas pipeline transportation system is mainly based on the steady-state operation model, that is, the transmission of hydrogen-blended natural gas in the pipeline is completed instantaneously, without considering the delay characteristics of hydrogen-blended natural gas flow transmission, and does not involve the influence of pipeline transportation conditions. The technology of the present invention establishes a dynamic operation characteristic model of the hydrogen-blended natural gas pipeline transportation system by considering the changes in the pressure, permeability, attenuation and other characteristics of the system after hydrogen is added to the natural gas pipeline, and considering the dynamic compression ratio of the compressor to reflect the operating efficiency of energy storage. In order to reduce the complexity and solution difficulty of the dynamic model, the finite difference method is used to discretize the partial differential equations describing the flow process of hydrogen-blended natural gas in time and space. By setting a smaller spatial step size, a virtual energy storage characteristic model of the hydrogen-blended natural gas pipeline transportation system considering pipeline storage and operation constraints is constructed, which solves the problems of coupled interaction between energy flow and material flow, complex morphology, and difficulty in characterizing energy storage characteristics in the hydrogen transmission link of new energy green electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a flow chart of a method for modeling virtual energy storage characteristics of a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration according to an embodiment of the present invention. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0012] The present invention provides a virtual energy storage characteristic modeling method for a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration. Under the background of the rapid development of electric-hydrogen fusion technology, a dynamic operation characteristic model of a hydrogen-blended natural gas pipeline transportation system is constructed based on the physical properties of hydrogen-blended natural gas in the hydrogen transmission pipeline. The finite difference method is used to discretize the partial differential equations describing the flow process of the hydrogen-blended natural gas, and a pipeline storage model and its operation constraints are established, thereby reducing the complexity of the dynamic model and the difficulty of solving the problem.

[0013] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below through specific implementations and in conjunction with the accompanying drawings.

[0014] like Figure 1 As shown, a method for modeling virtual energy storage characteristics of a hydrogen-blended natural gas pipeline transportation system considering pipeline storage is provided in an embodiment of the present invention, comprising the following steps: Step S1: Based on the physical properties of natural gas and hydrogen, a physical property model of natural gas blended with hydrogen in a hydrogen pipeline is constructed, which is used in step S2 to obtain changes in the system after hydrogen is blended into the natural gas pipeline; Step S2: Considering the changes in the system's pressure, permeation, attenuation and other characteristics after hydrogen is added to the natural gas pipeline, and taking into account the dynamic compression ratio to build a compressor power consumption model, maintain the pressure balance of the hydrogen-added natural gas pipeline, and establish a dynamic operation characteristic model of the hydrogen-added natural gas pipeline transportation system, so as to provide a model basis for establishing a dynamic operation characteristic model and operation constraints of the hydrogen-added natural gas pipeline transportation system considering pipeline storage; Step S3: Considering the pipeline storage, the finite difference method is used to discretize the partial differential equation describing the flow process of hydrogen-blended natural gas, and the operation constraints of the hydrogen-blended natural gas pipeline transportation system are constructed.

[0015] Specifically, according to Figure 2 The schematic diagram of the hydrogen-blended natural gas pipeline transportation system considering pipeline storage is shown. Natural gas and hydrogen produced by electric hydrogen production equipment through new energy are mixed in the pipeline. After the mixed gas passes through the compressor, part of it flows out of the pipeline, and the other part remains in the pipeline for pipeline storage. The step S1 includes: Step S11: Since the main component of natural gas is methane, for the convenience of calculation, the physical properties of natural gas are approximately regarded as the physical properties of methane, and the two gases are mixed in different proportions. The relative molecular mass M of the mixed gas is HCNG The calculation is as follows: ; Among them, M H , M NG are the relative molecular masses of hydrogen and natural gas respectively; θ h is the volume fraction of hydrogen, i.e., the hydrogen doping ratio; Step S12: The gas density is usually related to the environmental parameters in which it is located. In order to calculate the physical properties of the mixed gas after hydrogen is mixed with natural gas, the actual gas state equation is used to calculate the mixed gas density ρ, as shown in the following formula: ; Among them, p HCNG is the pressure of the mixed gas; Z is the compressibility factor of the gas; R is the gas constant, which is 8.314 J / (mol·K); T HCNG is the mixed gas temperature; The calculation of the gas compressibility factor Z is shown below: ; Among them, p and p c are the actual pressure and quasi-critical pressure of the gas, respectively; T and T c It is divided into the actual temperature of the gas and the quasi-critical temperature; it can be estimated based on the gas component ratio; Step S13: Mixed gas calorific value H HCNG The calculation is as follows: ; ; Among them, H0 is the ideal calorific value of the mixed gas, H H and H NG are the calorific values ​​of hydrogen and natural gas, respectively; Step S14: Viscosity μ of the mixed gas HCNG The calculation is shown below; ; Among them, μ H and μ NG are the viscosities of hydrogen and natural gas, respectively.

[0016] After step S1, a physical property model of hydrogen-blended natural gas in a hydrogen transmission pipeline is established, providing calculation support for obtaining the delay characteristics of the hydrogen-blended natural gas pipeline and constructing a dynamic operation characteristic model.

[0017] Specifically, the step S2 includes: Step S21: During the transportation of hydrogen-blended natural gas, due to friction loss, the pressure of the mixed gas in the pipeline will be lower than the pressure at the pipeline inlet. In addition, changes in pipeline elevation will also affect the pressure of the transported gas. The pressure drop model of the pipeline is established as shown in the following formula: ; ; Where Δp is the pressure drop per kilometer of the pipeline; f is the friction coefficient of the pipeline; L is the length of the pipeline; v HCNG is the flow rate of the gas in the pipeline; D is the outer diameter of the pipeline; g is the local gravity acceleration, which is 9.8 m / s 2 ; Δh is the elevation change of the pipeline. Q HCNG is the standard volume flow rate of pipeline gas; p0 is the pressure under standard conditions; T0 is the temperature under standard conditions; The friction coefficient reflects the degree of friction between gas molecules and between gas molecules and the inner wall of the pipeline when the gas flows in the pipeline. It is one of the important parameters affecting the calculation of pipeline pressure drop. The calculation is shown in the following formula: ; ; Among them, K e is the relative roughness of the inner wall of the natural gas pipeline; R e is the Reynolds number; Step S22: In order to ensure the transportation efficiency of the gas pipeline, a gas compressor station needs to be added along the pipeline to pressurize the transported gas to supplement the pressure energy consumed when the gas flows along the natural gas pipeline, maintain the pipeline at a set pressure, and ensure that the gas is transported to the pipeline end at the required flow rate.

[0018] The core component of the compressor station is the compressor, and its power consumption directly affects the energy efficiency of hydrogen storage. Under isentropic conditions, the air intake volume and compression ratio are the main factors affecting the power consumption of the compressor. Under the condition that the air intake volume is known, the compression ratio is the pressure ratio between the compressor outlet and the air inlet. In general, the pressure at the compressor inlet is constant. In order to accurately evaluate the power consumption of the compressor, the following compressor power consumption model is established considering the dynamic compression ratio, as shown in the following formula: ; ; Among them, P HS_C,t is the operating power consumption of the compressor in the hydrogen storage link at time t; H is the average volumetric polynomial index of hydrogen; m HS_in,t is the mass of the compressor inlet at time t; W HS_C,t is the power consumption of compressing unit molar mass of hydrogen at time t; p HS_C,out 、p HS_C,in are the pressure at the compressor outlet and inlet respectively; η HS_C is the compression efficiency of the compressor; is the hydrogen temperature; The compression ratio of the compressor station is set to a fixed value. Under the condition of ensuring a certain pipeline transportation flow rate, the pressure loss in the hydrogen transmission link is only related to the number of compressor stations built along the way. The above formula can be converted into: ; Among them, P TP_C,t is the operating power consumption of the compressor of the compressor station at time t; HCNG is the average volumetric polynomial index of hydrogen-blended natural gas; m TP_in,t is the mass flow rate at the compressor inlet at time t; η TP_C is the compression efficiency of the compressor; k pr is the compression ratio of the compressor; T HCNG is the mixed gas temperature; The temperature characteristic model of the compressor station is established as shown in the following formula: ; in, For the The outlet temperature of each compressor station; For the The inlet temperature of each compressor station; For the The suction pressure of each compressor station; For the The exhaust pressure of each compressor station; is the mean temperature variability index; Step S23: Corrosion is one of the main reasons for the failure of natural gas pipelines. After hydrogen enters the natural gas pipeline, hydrogen molecules decompose into hydrogen atoms on the metal surface and enter the metal interior, resulting in a decrease in the ductility and particle resistance of the material, which increases the corrosion rate of the pipeline and affects the service life of the pipeline. The service life of the natural gas pipeline is T P The calculation is as follows: ; Among them, d pipe,start is the initial wall thickness of the pipe; d min The minimum allowable wall thickness of the pipe, generally 20% of the pipe wall thickness; v cr is the corrosion rate of the pipeline; Pipeline corrosion rate v cr It will accelerate with the increase of hydrogen concentration, and the calculation is shown as follows: ; Among them, v cr,0 is the annual average corrosion rate of the pipeline without hydrogen addition, which is 0.42mm / a; The remaining wall thickness of the pipeline can be calculated based on the corrosion rate of the pipeline, as shown in the following formula: ; Among them, d pipe,t is the remaining wall thickness of the pipe at time t, t P is the length of time the pipeline has been in service; Step S24: Due to the physical properties of hydrogen, such as small molecules, high diffusion coefficient and low viscosity, hydrogen is more likely to penetrate and leak from the pores of the pipeline than methane and hydrocarbons under the same pressure and pore size. During the transportation process, as hydrogen is added, the gas will penetrate into the air through the pipeline, resulting in energy loss. When the permeation flow rate is too high, there may even be a risk of explosion. The permeation flow model of the pipeline is established as shown in the following formula: ; Among them, Q per,t is the gas permeation flow rate of the pipeline at time t; p is the gas permeability; A is the cross-sectional area of ​​the pipeline; The gas permeability in the pipeline is a function of temperature change and is also affected by the hydrogen doping ratio. The calculation is shown in the following formula: ; ; Among them, λ0 is the permeability constant of the pipeline; E is the energy per unit mass of the mixed gas.

[0019] After step S2, the changes in the system's pressure, permeation, attenuation and other characteristics after hydrogen is added to the natural gas pipeline are taken into consideration, and a dynamic operation characteristic model of the hydrogen-added natural gas pipeline transportation system is established to provide model support for building a pipeline storage model and its operation constraints.

[0020] Specifically, step S3 includes: Step S31: Establish a pipeline dynamic model, as shown in the following formula: ; ; in, is the pipeline flow rate; is the gas sound speed; is the inner diameter of the pipe; Indicates the length of space; is the cross-sectional area of ​​the pipe; By using the finite difference method to discretize the above equation in time and space, we can get the following equation: ; ; in, , They represent the time step and space step selected by the finite difference method respectively; and Respectively Moment Pipeline density and pipe flow at the differential point; represents the difference points selected by the finite difference method; Step S32: Due to the compressibility of hydrogen-blended natural gas, part of it will be stored in the pipeline, which is called pipeline storage. When there is pipeline storage, the inflow and outflow of hydrogen-blended natural gas in a section of pipeline are not equal. When the inflow is greater than the outflow, the pipeline storage is stored and the pipeline storage increases. When the inflow is less than the outflow, the pipeline storage is consumed and the pipeline storage decreases.

[0021] The pipe length As the spatial step length, the average flow rate at both ends of the pipeline is Replace pipe flow term , the management model can be obtained as follows: ; ; ; ; in, and They represent the density at the starting point and the end point of the pipeline respectively; and They represent the flow rate flowing into the pipe and the flow rate flowing out of the pipe respectively; Represents a pipeline The coefficient of Represents a pipeline Traffic volume; Represents a pipeline Length; Represents a pipeline The inner diameter of Represents a pipeline The cross-sectional area of Represents a pipeline exist The average flow rate at both ends at the time; Step S33: Pipeline storage is an important flexibility resource in the hydrogen-blended natural gas pipeline transportation system. In order to avoid a large consumption of pipeline storage during the scheduling cycle, it is usually necessary to restore the pipeline storage to near the initial level after one operation cycle to ensure the flexibility of the system in the subsequent scheduling cycle. The pipeline storage constraint is shown in the following formula: ; in, Indicates the entire running time range; Represents the collection of all pipelines; and represent the pipe flow into and out of the node respectively; Represents the number of discrete points selected by the finite difference method; Indicates the allowable change in pipe inventory; Indicates the selected pipeline.

[0022] After step S3, the partial differential equation describing the flow process of hydrogen-blended natural gas is discretized using the finite difference method, and a pipeline storage model reflecting the dynamic characteristics of the hydrogen-blended natural gas system is established by setting a smaller spatial step size, taking into account both model accuracy and complexity.

[0023] The present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the steps of the method are implemented when the processor executes the program.

[0024] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which implements the steps of the method when executed by a processor.

[0025] In summary, the present invention discloses a method for modeling virtual energy storage characteristics of a hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration. In order to solve the problems of coupled interaction between energy flow and material flow, complex morphology, and difficulty in characterizing energy storage characteristics in the hydrogen transmission link of current new energy green electricity, it is proposed to consider the changes in pressure, permeability, attenuation and other characteristics of the system after hydrogen is blended into the natural gas pipeline, and to construct a compressor power consumption model taking into account the dynamic compression ratio, and to establish a dynamic operation characteristic model of the hydrogen-blended natural gas pipeline transportation system. In order to reduce the complexity and solution difficulty of the dynamic model, the finite difference method is used to discretize the partial differential equations describing the flow process of the hydrogen-blended natural gas in time and space. By setting a smaller spatial step size, a virtual energy storage characteristic model of the hydrogen-blended natural gas pipeline transportation system taking pipeline storage into consideration and operation constraints are constructed.

[0026] It should be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and interpreted scripting language JavaScript, etc.

[0027] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks 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 produce 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.

[0028] 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.

[0029] 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 in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0030] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0031] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A virtual energy storage characteristics modeling method for a hydrogen-blended natural gas pipeline transportation system considering pipeline storage, characterized in that: The steps include: Step S1: Based on the physical properties of natural gas and hydrogen, a physical property model of hydrogen-blended natural gas in a hydrogen transmission pipeline is constructed to provide a model basis for obtaining changes in the system after hydrogen is blended into the natural gas pipeline; Step S2: Considering the changes in the pressure, permeation, and attenuation characteristics of the system after hydrogen is added to the natural gas pipeline, and taking into account the dynamic compression ratio to build a compressor power consumption model, maintain the pressure balance of the hydrogen-added natural gas pipeline, and establish a dynamic operation characteristic model of the hydrogen-added natural gas pipeline transportation system, so as to provide a model basis for establishing a dynamic operation characteristic model of the hydrogen-added natural gas pipeline transportation system considering pipeline storage and operation constraints; Step S3: Considering the pipeline storage, the finite difference method is used to discretize the partial differential equations describing the flow process of hydrogen-blended natural gas in time and space, and the operation constraints of the hydrogen-blended natural gas pipeline transportation system are constructed.

2. A virtual energy storage characteristics modeling method for a hydrogen-blended natural gas pipeline transportation system considering pipeline storage according to claim 1, characterized in that: The step S1 specifically includes: Step S11: The physical properties of natural gas are approximately regarded as the physical properties of methane, and hydrogen and natural gas are mixed in different proportions. The relative molecular mass M of the mixed gas is HCNG The calculation is as follows: ； Among them, M H , M NG are the relative molecular masses of hydrogen and natural gas respectively; θ h is the volume fraction of hydrogen, i.e., the hydrogen doping ratio; Step S12: To calculate the physical properties of the mixed gas after hydrogen is mixed with natural gas, the density ρ of the mixed gas is calculated using the actual gas state equation, as shown in the following formula: ； Among them, p HCNG is the pressure of the mixed gas; Z is the compressibility factor of the gas; R is the gas constant, which is 8.314 J / (mol·K); T HCNG is the mixed gas temperature; The calculation of the gas compressibility factor Z is shown below: ； Among them, p and p c are the actual pressure and quasi-critical pressure of the gas, respectively; T and T c Divided into actual temperature and quasi-critical temperature of the gas; estimated based on gas component ratio; Step S13: Mixed gas calorific value H HCNG The calculation is as follows: ； ； Among them, H0 is the ideal calorific value of the mixed gas, H H and H NG are the calorific values ​​of hydrogen and natural gas, respectively; Step S14: Viscosity μ of the mixed gas HCNG The calculation is shown below; ； Among them, μ H and μ NG are the viscosities of hydrogen and natural gas, respectively.

3. A virtual energy storage characteristic modeling method for a hydrogen-blended natural gas pipeline transportation system considering pipeline storage according to claim 2, characterized in that: The step S2 specifically includes: Step S21: Establish a pipeline pressure drop model as shown below: ； ； Where Δp is the pressure drop per kilometer of the pipeline; f is the friction coefficient of the pipeline; L is the length of the pipeline; v HCNG is the flow rate of the gas in the pipeline; D is the outer diameter of the pipeline; g is the local gravity acceleration, which is 9.8 m / s 2 ; Δh is the elevation change of the pipeline; Q HCNG is the standard volume flow rate of pipeline gas; p0 is the pressure under standard conditions; T0 is the temperature under standard conditions; The calculation of the friction coefficient f of the pipeline is shown as follows: ； ； Among them, K e is the relative roughness of the inner wall of the natural gas pipeline; R e is the Reynolds number; Step S22: Considering the dynamic compression ratio, establish the following compressor power consumption model, as shown in the following formula: ； ； Among them, P HS_C,t is the operating power consumption of the compressor in the hydrogen storage link at time t; H is the average volumetric polynomial index of hydrogen; m HS_in,t is the mass of the compressor inlet at time t; W HS_C,t is the power consumption of compressing unit molar mass of hydrogen at time t; p HS_C,out 、p HS_C,in are the pressure at the compressor outlet and inlet respectively; η HS_C is the compression efficiency of the compressor; The compression ratio of the compressor station is set to a fixed value. Under the condition of ensuring a certain pipeline transportation flow rate, the pressure loss in the hydrogen transmission link is only related to the number of compressor stations built along the way. The above formula is converted into: ； Among them, P TP_C,t is the operating power consumption of the compressor of the compressor station at time t; HCNG is the average volumetric polynomial index of hydrogen-blended natural gas; m TP_in,t is the mass flow rate at the compressor inlet at time t; η TP_C is the compression efficiency of the compressor; k pr is the compression ratio of the compressor; The temperature characteristic model of the compressor station is established as shown in the following formula: ； in, For the The outlet temperature of each compressor station; For the The inlet temperature of each compressor station; For the The suction pressure of each compressor station; For the The exhaust pressure of each compressor station; is the mean temperature variability index; Step S23: Service life T of natural gas pipeline P The calculation is as follows: ； Among them, d pipe,start is the initial wall thickness of the pipe; d min is the minimum allowable wall thickness of the pipe, which is 20% of the pipe wall thickness; v cr is the corrosion rate of the pipeline; The corrosion rate increases with the increase of hydrogen concentration, as shown in the following formula: ； Among them, v cr,0 is the annual average corrosion rate of the pipeline without hydrogen addition, which is 0.42 mm / a; mm / a means millimeter / year; The remaining wall thickness of the pipeline can be calculated based on the corrosion rate of the pipeline, as shown in the following formula: ； Among them, d pipe,t is the remaining wall thickness of the pipe at time t, t P is the length of time the pipeline has been in service; Step S24: Establish a pipeline permeation flow model as shown below: ； Among them, Q per,t is the gas permeation flow rate of the pipeline at time t; p is the gas permeability; A is the cross-sectional area of ​​the pipeline; The gas permeability in the pipeline is a function of temperature change and is also affected by the hydrogen doping ratio. The calculation is shown in the following formula: ； ； Among them, λ0 is the permeability constant of the pipeline; E is the energy per unit mass of the mixed gas.

4. A virtual energy storage characteristic modeling method for a hydrogen-blended natural gas pipeline transportation system considering pipeline storage according to claim 3, characterized in that: The step S3 specifically includes: Step S31: Establish a pipeline dynamic model, as shown in the following formula: ； ； in, is the pipeline flow rate; is the gas sound speed; is the inner diameter of the pipe; The above equation is discretized in time and space using the finite difference method to obtain the following equation: ； ； in, , They represent the time step and space step selected by the finite difference method respectively; and Respectively Moment Pipeline density and pipe flow at the differential point; Step S32: Set the pipeline length As the spatial step length, the average flow rate at both ends of the pipeline is Replace pipe flow term , the pipe storage model is as follows: ； ； ； ； in, and Respectively represent the density at the starting point and the end point of the pipeline; and They represent the flow rates into and out of the pipe respectively; Step S33: The storage constraint is as follows: ； in, Indicates the entire running time range; Represents the collection of all pipelines; and represent the pipe flow into and out of the node respectively; Represents the number of discrete points selected by the finite difference method; Indicates the allowable change in pipe inventory.

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