Hydrogen-doped natural gas metering method and system, storage medium and electronic equipment

Abstract

The invention relates to the technical field of natural gas metering, and discloses a hydrogen-doped natural gas metering method and system, a storage medium and electronic equipment. The method comprises the following steps: acquiring a hydrogen-doped natural gas sample from hydrogen-doped natural gas to be metered; determining the composition and calorific value of the hydrogen-doped natural gas sample; determining an analysis measurement standard applicable to the hydrogen-doped natural gas to be measured based on the component composition and the calorific value; and carrying out volume metering on the hydrogen-doped natural gas to be metered based on the analysis metering standard. According to the method, firstly, the component composition and the calorific value of the hydrogen-doped natural gas are obtained, then the matched analysis and measurement standard is determined according to the component composition and the calorific value of the hydrogen-doped natural gas, then the volume of the hydrogen-doped natural gas is measured under the selected analysis and measurement standard, and it is ensured that the hydrogen-doped natural gas is accurately and efficiently measured.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas metering, and in particular to a method, system, storage medium and electronic equipment for metering hydrogen-blended natural gas. Background Art

[0002] At present, the production of hydrogen by electrolysis of water is an efficient and clean technology, and the purity of the produced hydrogen is as high as 99%. The energy conversion efficiency from electricity to hydrogen energy reaches 60%-80%. When hydrogen energy is burned and used, the remaining heat can be recovered. Compared with traditional fossil fuels, the combustion of hydrogen produces almost no carbon emissions and is a very clean and environmentally friendly energy. Therefore, the way of converting electricity to hydrogen energy is more in line with the future world's requirements for clean and environmentally friendly energy.

[0003] At present, most of the burners designed use natural gas or liquefied petroleum gas, so hydrogen cannot be used directly as a fuel. Today's natural gas pipeline network is relatively mature, and hydrogen can be mixed into the natural gas pipeline network for use. At present, the transportation capacity of the natural gas pipeline network is very large. If the excess electricity is converted into hydrogen and mixed into the natural gas pipeline network for use, it will not cause waste of resources. In 2018, the global demand for natural gas reached 3.9 trillion cubic meters, of which 3% of hydrogen can drive the consumption of 12 million tons of hydrogen, which is conducive to easing the pressure on natural gas supply, promoting the large-scale consumption of hydrogen energy, and building a clean and environmentally friendly energy structure. Therefore, natural gas mixed with hydrogen is an important way to effectively transport and utilize hydrogen.

[0004] However, the physical properties of hydrogen and natural gas are quite different in terms of density, calorific value, diffusion characteristics, combustion characteristics, etc., which makes the traditional natural gas metering method unsuitable for the metering of hydrogen-blended natural gas. At present, the metering of hydrogen-blended natural gas is still in a blank stage, and an effective metering system has not yet been formed. Therefore, considering the future development trend of hydrogen-blended natural gas, how to achieve efficient metering of hydrogen-blended natural gas has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a hydrogen-blended natural gas metering method, system, storage medium and electronic equipment in view of the problems existing in the prior art.

[0006] In a first aspect, the present invention provides a method for measuring hydrogen-blended natural gas, comprising:

[0007] obtaining a hydrogen-blended natural gas sample from the hydrogen-blended natural gas to be metered;

[0008] Determine the composition and calorific value of hydrogen-blended natural gas samples;

[0009] Determine the analytical and measurement standards applicable to the hydrogen-blended natural gas to be measured based on the component composition and calorific value;

[0010] The volume of hydrogen-blended natural gas to be measured is measured based on analytical measurement standards.

[0011] In a second aspect, the present invention provides a hydrogen-blended natural gas metering system, which is used to implement the hydrogen-blended natural gas metering method provided by the above technical solution, and the system includes:

[0012] A sample acquisition module, used for acquiring a hydrogen-blended natural gas sample from the hydrogen-blended natural gas to be measured;

[0013] Energy determination module, used to determine the composition and calorific value of hydrogen-blended natural gas samples;

[0014] Standard screening module, used to determine the applicable analytical and measurement standards for the hydrogen-blended natural gas to be measured based on the component composition and calorific value;

[0015] The metering module is used to perform volume measurement of hydrogen-blended natural gas to be measured based on analytical metering standards.

[0016] In a third aspect, the present invention provides a computer-readable storage medium, comprising instructions, which, when executed on a computer, enable the computer to execute the hydrogen-blended natural gas metering method provided by the above technical solution.

[0017] In a fourth aspect, the present invention 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 hydrogen-blended natural gas metering method provided by the above technical solution is implemented.

[0018] In a fifth aspect, the present application also provides a computer program product, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the hydrogen-blended natural gas metering method provided by the above solution.

[0019] The beneficial effects of the present invention are as follows: natural gas is compressible, and its volume can change with changes in pressure and temperature, so volume measurement must specify the pressure and temperature conditions during measurement, namely the so-called analytical measurement standard. The present invention first obtains the component composition and calorific value of hydrogen-blended natural gas, and then determines the matching analytical measurement standard according to the component composition and calorific value of hydrogen-blended natural gas, and then measures the volume of hydrogen-blended natural gas under the selected analytical measurement standard, ensuring accurate and efficient measurement of hydrogen-blended natural gas.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a method for measuring hydrogen-blended natural gas according to an exemplary embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of a hydrogen-blended natural gas transportation system provided in an embodiment of the present invention;

[0023] Figure 3 A flow chart of gas volume calculation under standard reference conditions provided by an embodiment of the present invention;

[0024] Figure 4 A block diagram of a hydrogen-blended natural gas metering system according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0025] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0026] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein may be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein may be implemented independently of any other aspect, and two or more of these aspects may be combined in various ways. For example, any number of aspects described herein may be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein may be used to implement this device and / or practice this method.

[0027] The solution provided in the embodiments of the present invention can be executed by any electronic device, for example, a terminal device, or jointly executed by a terminal device and a server. The server can be an independent server, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, content delivery networks (CDNs), and big data and artificial intelligence platforms, etc., and is not limited here.

[0028] Figure 1 The following is a flow chart of a method for measuring hydrogen-blended natural gas according to an exemplary embodiment of the present application. Figure 1 As shown, in an exemplary embodiment, the hydrogen-blended natural gas metering may include steps S101 to S104, which are described in detail as follows:

[0029] S101, obtaining a hydrogen-blended natural gas sample from the hydrogen-blended natural gas to be measured;

[0030] S102, determining the component composition and calorific value of the hydrogen-blended natural gas sample;

[0031] S103, determining the analytical measurement standard applicable to the hydrogen-blended natural gas to be measured based on the component composition and calorific value;

[0032] S104, performing volume measurement on the hydrogen-blended natural gas to be measured based on the analytical measurement standard.

[0033] Natural gas is compressible and its volume can change with changes in pressure and temperature. Therefore, volume measurement must specify the pressure and temperature conditions at the time of measurement, which is the so-called analytical measurement standard. When measuring the volume of hydrogen-blended natural gas, it is necessary to convert the volume of hydrogen-blended natural gas measured under reference conditions into the volume under standard conditions. The conversion process depends on pressure, temperature and compression coefficient, which is related to temperature and pressure.

[0034] Therefore, the embodiment of the present invention first obtains the component composition and calorific value of the hydrogen-blended natural gas, then determines the matching analysis and measurement standard according to the component composition and calorific value of the hydrogen-blended natural gas, and then measures the volume of the hydrogen-blended natural gas under the selected analysis and measurement standard to ensure accurate and efficient measurement of the hydrogen-blended natural gas.

[0035] Due to the physical property differences between hydrogen and natural gas in terms of density, calorific value, diffusion characteristics, combustion characteristics, etc., natural gas pipeline hydrogen blending technology mainly brings two challenges: (1) risks such as material compatibility and pipeline integrity in the pipeline network; (2) impacts such as fuel interchangeability and safety in the terminal burner.

[0036] After hydrogen molecules are adsorbed on the surface of steel, they are easily decomposed into hydrogen atoms. Hydrogen atoms have extremely small atomic radius and can easily diffuse as interstitial atoms in the metal crystal lattice. Hydrogen atoms diffused in the metal are easily enriched in defects and stress concentrations, causing cracks or hydrogen bubbling, leading to pipe failure. Usually, the occurrence of hydrogen embrittlement is affected by the coupling of three factors: material, environment, and stress. When pipeline steel is stretched in hydrogen-doped natural gas, the loss of mechanical properties of the notched specimen is significantly higher than that of the smooth specimen. This shows that when there are defects or cracks in the pipeline steel, hydrogen added to the natural gas will cause the cracks to expand rapidly and eventually cause pipe failure, which may cause gas leakage and explosion risks.

[0037] The interchangeability of gas refers to the property that gas of different types or sources can be used interchangeably in the same combustion equipment and application conditions. In short, if two gases have similar calorific value and combustion characteristics, they can be considered interchangeable.

[0038] When considering the interchangeability of gas, key factors include the calorific value, combustion rate, density, impurities and toxic components of the gas. The calorific value is the amount of heat released when the gas burns, which directly affects the thermal efficiency of the combustion equipment. The combustion rate determines the combustion stability of the gas in the burner. Too fast or too slow a combustion rate may lead to incomplete combustion or unstable flames. The density of the gas affects its transportation and storage methods. In addition, impurities and toxic components in the gas may affect the operation of the combustion equipment and the health of the user.

[0039] Calculated according to the average high calorific value of natural gas of 37.8MJ / m3, when the hydrogen blending ratio is controlled within 23%, the gas quality meets the measurement standard of 12T benchmark gas in GB / T13611-2018 "Classification and Basic Characteristics of Urban Gas".

[0040] my country's current standard GB / T37124-2018 "Quality Requirements for Gas Entering Long-distance Natural Gas Pipelines" stipulates that the upper limit of the hydrogen gas volume fraction (hereinafter the same) in natural gas is 3%. In terms of hydrogen blending transportation, after a minor modification of urban gas pipelines, it is safe and feasible to blend hydrogen by volume ≤10%. The main limitation of the hydrogen blending ratio in long-distance pipelines is the adaptability of high-grade steel pipes under high pressure.

[0041] The physical and chemical properties of methane, the main component of hydrogen and natural gas, are shown in Table 1. The density, lower calorific value, and higher calorific value in Table 1 are all values ​​at 20°C and standard atmospheric pressure.

[0042] Table 1

[0043] nature Methane hydrogen Relative molecular weight 16.04 2.02 Critical temperature (k) 190.65 33.2 Critical pressure (MPa) 4.540 1.315 <![CDATA[Density (kg / m -3 )]]> 0.714 0.089 <![CDATA[Low calorific value (MJ / m -3 )]]> 35.82 10.80 <![CDATA[High calorific value (MJ / m -3 )]]> 37.77 12.09 Flame constant 0.67 0.60 Explosion limit (%) 5.7～14.0 18.2～58.6 <![CDATA[Theoretical air requirement (m 3 ·m -3 )]]> 9.524 2.381 <![CDATA[Diffusion coefficient to air (m 2 ·s -1 )]]> 1.6x10-5 6.1x10-5

[0044] The theoretical amount of air required per unit calorific value and the theoretical amount of flue gas produced per unit calorific value decrease significantly when the volume percentage of hydrogen added is 75% to 80%.

[0045] Theoretically, when the volume percentage of hydrogen mixed into natural gas is below 70%, the change is relatively stable (gradually decreasing). Combined with the feasibility analysis theory of using natural gas pipelines to transport hydrogen: the high permeability of hydrogen and the existence of hydrogen embrittlement make the requirements for pipes and their processing particularly high for transporting hydrogen and natural gas mixtures. From the perspective of end users, if the original equipment is to work properly, the volume fraction of hydrogen in hydrogen-mixed natural gas should be controlled within 23%.

[0046] Optionally, the embodiment of the present invention can determine the component composition of the hydrogen-doped natural gas sample by an offline analysis method or an online analysis method. The offline analysis method is an offline gas chromatography analysis method; the online analysis method is an online gas chromatography analysis method or an external standard method; the online gas chromatography analysis method uses argon as a carrier gas and hydrogen as a target gas, and uses an offline gas chromatograph to perform gas chromatography analysis to obtain the component composition of the hydrogen-doped natural gas sample.

[0047] Offline gas chromatography is a method of periodically sampling and analyzing in the laboratory using an offline gas chromatograph. Gas chromatography is a column chromatography separation technique that uses gas as the mobile phase and a flushing method. The main basis for separation is to use the different adsorption forces of the components in the sample in the chromatographic column, that is, to use the different distribution coefficients of the components in the gas phase and the stationary phase in the chromatographic column to achieve sample separation.

[0048] Online gas chromatography analysis refers to the use of online automatic samplers, online gas chromatographs and other instruments and equipment to automatically complete the sampling of natural gas within a specified time interval, and calculate the data information of natural gas by analyzing the components.

[0049] The principle of gas chromatography (GC) is based on the distribution behavior of compounds between gas phase and liquid phase, and the analysis is achieved through a series of complex physical and chemical processes. Its basic steps include sample injection, separation, detection and data processing. First, the sample is injected into the separation column of the gas chromatograph. In the separation column, the compound is vaporized at high temperature and then interacts with the liquid or solid fixed in the column. This step is actually a separation process, because different compounds move at different speeds in the column according to their chemical properties and affinity. This allows different components to be gradually separated and spread on the column. Secondly, the separated compounds enter the detector. The detector is one of the core components of gas chromatography, and highly sensitive instruments such as flame ionization detectors (FID) or mass spectrometers are usually used. In the detector, the compounds are excited and produce specific signals, which are related to the type and concentration of the compounds. By recording and analyzing these signals, the individual components in the separation column can be qualitatively and quantitatively analyzed.

[0050] Gas chromatography is a highly efficient separation technology that achieves separation by utilizing the differences in the distribution coefficients (or adsorption coefficients) of the components in the sample to be analyzed between the stationary phase and the mobile phase. The separated components enter the detector in sequence and are qualitatively analyzed based on the response time and quantitatively analyzed based on the response value.

[0051] In the embodiment of the present invention, the chromatography data processing device may be an Anjielun chromatography workstation, which can automatically collect chromatography data, permanently store it, and perform a variety of post-processing operations.

[0052] Since the external standard method uses standard gas, it has high accuracy and good traceability, and also increases the comparability and credibility of data between different laboratories. Since natural gas is sold as a commodity, the determination of natural gas heat must be accurate and reliable, with good traceability, and the component values ​​measured in different places should be comparable and credible. Therefore, in natural gas energy measurement, the use of external standard method to quantitatively analyze the components of natural gas will definitely become the first choice.

[0053] The embodiment of the present invention can select a variety of online or offline analysis methods to determine the component composition of the hydrogen-blended natural gas sample, thereby providing data support for the accurate measurement of the hydrogen-blended natural gas sample.

[0054] When measuring the calorific value, the embodiments of the present invention respectively adopt an online calorific value measurement process in a local metering station, an offline calorific value measurement process in a local metering station, and a remote calorific value measurement process.

[0055] The calorific value offline measurement process is adopted in the local metering station, that is, the natural gas is periodically sampled in the station, and then the calorific value is obtained through offline analysis.

[0056] When measuring calorific value, the premise is to obtain a representative mixed sample of natural gas and hydrogen. Since natural gas is constantly flowing in the pipeline, the sampling process will be affected by many factors, such as the distribution location of the sampling points, the operating procedures of the sampling process, the fluctuation of gas quality components, the effectiveness of the measurement system, etc.

[0057] Therefore, when sampling pipeline natural gas, the relevant provisions in the "Guidelines for Natural Gas Sampling" (GB / T13609-2017) must be strictly followed. Sampling can be divided into uninterrupted direct sampling, fixed-point fixed-period sampling, and incremental sampling. The natural gas samples taken can be analyzed online at the local metering station or sent to a remote location for offline analysis. Here, the method of periodic fixed-point sampling is adopted.

[0058] Calorific value determination is the core step of natural gas energy measurement. The direct method uses a special calorimeter to measure the actual heat released after a certain amount of natural gas is fully burned under specified conditions. This method is the most scientific and accurate calorific value determination method and is suitable for Figure 2 Interfaces 1 to 3 and interface 5 of the structural schematic diagram of the hydrogen-blended natural gas transportation system are shown.

[0059] The basic principle of the indirect method is to use a gas chromatograph to analyze the combustible components and molar fractions in natural gas, and then calculate the actual calorific value of natural gas by weighted average based on the calorific value of each pure substance. The implementation process of this method is relatively simple and easy to realize automatic management, so it is currently the most widely used, but it is easily affected by the water vapor content in natural gas. This method is suitable for Figure 2 Interfaces 1 to 3 and interface 5 of the structural schematic diagram of the hydrogen-blended natural gas transportation system are shown.

[0060] The correlation method characterizes the calorific value of gas by measuring several physical and chemical parameters related to the calorific value of natural gas. The substation is equipped with gas chromatograph, hydrogen sulfide analyzer, water / hydrocarbon dew point analyzer and other analytical instruments, and the indirect method can be used to determine the calorific value of natural gas.

[0061] Optionally, the embodiment of the present invention may use a calorimeter to measure the heat actually released after the preset metered hydrogen-blended natural gas sample is fully burned under specified conditions as the calorific value of the hydrogen-blended natural gas sample.

[0062] Optionally, the embodiment of the present invention may also determine the combustible components and mole fractions in the component composition of the hydrogen-blended natural gas sample; determine the calorific value of each combustible component, and calculate the calorific value of the hydrogen-blended natural gas sample by weighted average according to the mole fraction.

[0063] Optionally, the embodiment of the present invention determines the applicable analytical measurement standard for the hydrogen-blended natural gas to be measured based on the component composition and calorific value, including: determining the hydrogen concentration range of the hydrogen-blended natural gas to be measured according to the component composition; determining the matching analytical measurement standard according to the hydrogen concentration range, calorific value and a pre-established matching relationship; wherein the matching relationship characterizes the correspondence between the hydrogen concentration range and calorific value of the hydrogen-blended natural gas and the analytical measurement standard. The matching relationship in the embodiment of the present invention can be as shown in Table 2.

[0064] Table 2

[0065]

[0066]

[0067] The statistics of the applicable scope of hydrogen concentration, relative density and high calorific value in natural gas for some current natural gas products and analytical measurement standards are shown in Table 2. GB17820-2018 stipulates the minimum requirements for high calorific value of natural gas of different categories. Taking three typical natural gases as examples, to meet the requirements of high calorific value of Class I gas, the concentration of hydrogen in natural gas shall not be higher than 14%, 12% and 24% respectively. When the actual high calorific value of natural gas is lower, the allowed concentration of hydrogen will be lower.

[0068] For relevant standards for natural gas composition analysis, such as GB / T13610-2020, GB / T17281-2016, GB / T27894.3-2011, GB / T27894.6-2012, etc., the maximum hydrogen concentration range they are applicable to is 10%. When the hydrogen concentration is higher than the hydrogen concentration range recommended by the standard method, it is necessary to confirm whether the method can be applied to the analysis and testing of natural gas with higher hydrogen concentration.

[0069] For the calculation of natural gas physical properties, GB / T11062-2020 is applicable to the calculation of gas physical properties with a reference compression factor greater than 0.9, and is applicable when the hydrogen concentration of natural gas is between 0 and 100%; the GB / T17747 series of standards is applicable to a hydrogen concentration range of 0 to 10%, and it also stipulates the range of relative density and high calorific value. For natural gas with a hydrogen concentration exceeding 10% but less than 40%, relevant physical parameters, such as compression factor and sound velocity, can be calculated using the GB / T30491.2-0XX (equivalent to ISO20765-2:2015) that is being formulated.

[0070] The applicable range of natural gas relative density defined by standard methods for different types of natural gas flowmeters is 0.55-0.80. When the hydrogen concentration of some natural gas is greater than 3%, the relative density is less than 0.55. Targeted experimental tests are needed to verify whether the natural gas flowmeters currently in use are suitable for accurate measurement of hydrogen-blended natural gas with a relatively low relative density, and to revise the applicable scope of relevant standard methods.

[0071] The thermal conductivity of argon is significantly different from that of hydrogen and helium (as shown in Table 3 below). Therefore, the embodiment of the present invention adds an additional separation and detection process using Ar as carrier gas to the currently used gas chromatograph to achieve the analysis of the hydrogen concentration in hydrogen-doped natural gas.

[0072] Table 3

[0073]

[0074] The sound velocity calculation method recommended in GB / T30500-2014 is AGA Report No. 10 (equivalent to the calculation method in GB / T30491.1), and it is stipulated that the allowable deviation between the calculated sound velocity and the ultrasonic flowmeter test sound velocity is 0.2%. The comparative analysis in Section 1.2 shows that when the hydrogen concentration in natural gas is higher than 10%, there is a deviation of nearly 0.2% between the calculation results of GB / T30491.1-2014 and ISO20765-2:2015. Since the latter has a wider range of application for hydrogen-blended natural gas, it is recommended that the ultrasonic flowmeter sound velocity verification calculation method adopt the recommended method of ISO standard. At the same time, the compression factor calculation method GB / T17747.2-2011 recommended by JJG1003-2016 is applicable to hydrogen concentrations less than 10%. It is recommended to use ISO20765-2:2015 for compression factor calculations with hydrogen concentrations greater than 10%.

[0075] Optionally, an embodiment of the present invention performs volume measurement on the hydrogen-blended natural gas to be measured based on the analytical measurement standard, including: determining a compression coefficient calculated under the analytical measurement standard; and converting the measured volume of the hydrogen-blended natural gas obtained under reference conditions into a measured volume under standard conditions based on the compression coefficient.

[0076] The natural gas volume flow metering system consists of one or more metering loops. Usually, the flow meter measures the gas volume under actual operating conditions. The natural gas volume measurement device consists of a metering standard device, generally a turbine flow meter or an ultrasonic flow meter, plus equipment and facilities such as a temperature transmitter and a pressure transmitter. The volume of natural gas flowing through the cross section of the pipeline per unit time is converted into a volume measurement value under standard conditions.

[0077] Natural gas is compressible and its volume can change with changes in pressure and temperature. Therefore, volume measurement must specify the pressure and temperature conditions at the time of measurement, which are called standard conditions. The conversion of the natural gas volume measured under reference conditions to the volume under standard conditions is based on gas pressure, temperature and compression factor. The process of calculating the gas volume under standard reference conditions is as follows: Figure 3 shown.

[0078] Calculate the volume V under standard reference conditions from the volume V under reference conditions n for:

[0079] V n =V·z

[0080] Where V is the volume under reference conditions; z is the compressibility factor (i.e. Figure 3 ).

[0081] The compression factor z can be calculated by the following formula:

[0082]

[0083] Where: T n is the standard reference temperature; T is the reference temperature; P amb is the average atmospheric pressure at the measuring instrument; P is the reference pressure; P H2O is the partial pressure of water in natural gas; P n is the standard pressure; Z is the compression factor under reference conditions; Z n is the compression factor under standard reference conditions.

[0084] In the process of volume conversion, there is a key quantity that needs to be calculated, that is, the compression factor of natural gas under reference conditions. For the calculation of the standard volume of mixed gas such as natural gas, the first thing to do is to calculate the compression factor Z under the working condition.

[0085] By using the calculation method in GB / T 17747.2-1999, the natural gas compression factor is calculated with the detailed mole fraction composition and related pressure and temperature of the natural gas known. This calculation method is also called AGA8-92DC calculation method, which is mainly used for pipeline gas transmission within the pressure P and temperature T range where gas transmission and distribution are normal, and the calculation uncertainty is about 0.1%.

[0086] The embodiment of the present invention clarifies that hydrogen addition to natural gas has a significant impact on physical parameters. Compared with natural gas without hydrogen addition, the high calorific value, relative density, Wobbe index, and viscosity of conventional natural gas transported by pipeline with a hydrogen concentration of 40% decrease by about 27%, 35%, 10%, and 20%, respectively; under the conditions of 10MPa and 20℃, the compression factor and sound velocity of conventional natural gas increase by 18% and 34%, respectively. For every 1% increase in hydrogen concentration, the volume energy density of hydrogen-added natural gas decreases by about 1%.

[0087] In view of the problem that most of the online gas chromatographs currently used in natural gas metering stations cannot detect hydrogen, the embodiment of the present invention proposes to add an additional separation gas path to realize the detection of the hydrogen concentration in the hydrogen-blended natural gas, thereby ensuring the accurate analysis of the high-concentration hydrogen-blended natural gas.

[0088] For the calculation of compression factor and sound velocity of hydrogen-blended natural gas, ISO 20765-2:2015 is recommended as the calculation method standard for flow totalizers.

[0089] Figure 4 FIG. 1 is a block diagram of a hydrogen-blended natural gas metering system according to an exemplary embodiment of the present application. Figure 4 As shown, the hydrogen-blended natural gas metering system is used to implement the hydrogen-blended natural gas metering method provided in any of the above embodiments, and the system includes a sample acquisition module, an energy determination module, a standard screening module and a metering module.

[0090] The sample acquisition module is used to obtain hydrogen-blended natural gas samples from the hydrogen-blended natural gas to be measured; the energy determination module is used to determine the component composition and calorific value of the hydrogen-blended natural gas samples; the standard screening module is used to determine the analytical measurement standard applicable to the hydrogen-blended natural gas to be measured based on the component composition and calorific value; the measurement module is used to perform volume measurement on the hydrogen-blended natural gas to be measured based on the analytical measurement standard.

[0091] An embodiment of the present invention further provides a computer-readable storage medium, comprising instructions, which, when executed on a computer, enable the computer to execute the hydrogen-blended natural gas metering method provided in any of the above embodiments.

[0092] An embodiment of the present invention further 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 hydrogen-blended natural gas metering method provided in any of the above embodiments is implemented.

[0093] The embodiment of the present invention further provides a computer program product, which includes computer instructions, and the computer instructions are stored in a computer-readable storage medium. The processor of the computer device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions, so that the computer device executes the hydrogen-blended natural gas metering method provided in the above various optional embodiments.

[0094] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0095] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic, for example, the division of units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0096] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0097] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0098] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring hydrogen-blended natural gas, characterized in that: include: obtaining a hydrogen-blended natural gas sample from the hydrogen-blended natural gas to be metered; Determining the component composition and calorific value of the hydrogen-blended natural gas sample; Determining the analytical measurement standard applicable to the hydrogen-blended natural gas to be measured based on the component composition and calorific value; The volume of the hydrogen-blended natural gas to be measured is measured based on the analytical measurement standard.

2. The method according to claim 1, characterized in that The determining of the component composition of the hydrogen-blended natural gas sample includes: determining the component composition of the hydrogen-blended natural gas sample based on an off-line analysis method or an on-line analysis method.

3. The method according to claim 2, characterized in that The off-line analysis method is an off-line gas chromatography analysis method, and the on-line analysis method is an on-line gas chromatography analysis method or an external standard method; The online gas chromatography analysis method uses argon as carrier gas and hydrogen as target gas, and utilizes an offline gas chromatograph to perform gas chromatography analysis to obtain the component composition of the hydrogen-doped natural gas sample.

4. The method according to claim 1, characterized in that: Determining the calorific value of the hydrogen-blended natural gas sample includes: using a calorimeter to measure the heat actually released after the preset amount of the hydrogen-blended natural gas sample is fully burned under specified conditions as the calorific value of the hydrogen-blended natural gas sample.

5. The method according to claim 1, characterized in that The step of determining the calorific value of the hydrogen-blended natural gas sample comprises: Determining the combustible components and molar fractions in the composition of the hydrogen-blended natural gas sample; The calorific value of each combustible component is determined, and the calorific value of the hydrogen-blended natural gas sample is calculated by weighted average according to the mole fraction.

6. The method according to any one of claims 1 to 5, characterized in that: The determination of the applicable analytical measurement standard for the hydrogen-blended natural gas to be measured based on the component composition and calorific value includes: Determining the hydrogen concentration range of the hydrogen-blended natural gas to be metered according to the component composition; Determine a matching analytical measurement standard according to the hydrogen concentration range, the calorific value and a pre-established matching relationship; The matching relationship represents the corresponding relationship between the hydrogen concentration range and calorific value of the hydrogen-blended natural gas and the analytical measurement standard.

7. The method according to claim 6, characterized in that The volume measurement of the hydrogen-blended natural gas to be measured based on the analytical measurement standard includes: determining a compression factor calculated under the analytical metrology standard; The metered volume of hydrogen-blended natural gas obtained under reference conditions is converted into a metered volume under standard conditions based on the compression coefficient.

8. A hydrogen-blended natural gas metering system, characterized in that: For implementing the hydrogen-blended natural gas metering method according to any one of claims 1 to 7, the system comprises: A sample acquisition module, used for acquiring a hydrogen-blended natural gas sample from the hydrogen-blended natural gas to be measured; An energy determination module, used to determine the component composition and calorific value of the hydrogen-blended natural gas sample; A standard screening module, used to determine the analytical measurement standard applicable to the hydrogen-blended natural gas to be measured based on the component composition and calorific value; The metering module is used to perform volume measurement on the hydrogen-blended natural gas to be measured based on the analytical metering standard.

9. A computer-readable storage medium comprising instructions, characterized in that: When the instructions are executed on a computer, the computer is enabled to execute the hydrogen-blended natural gas metering method according to any one of claims 1 to 7.

10. An electronic device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the hydrogen-blended natural gas metering method according to any one of claims 1 to 7 when executing the program.

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