A method for filling mixed gas standard materials for natural gas analysis

Abstract

This invention provides a method for filling a mixed gas standard substance for natural gas analysis. The method includes: determining the total molar amount of the standard substance to be filled based on the mixed gas standard substance for natural gas analysis; determining the molar component of each component in the mixed gas standard substance for natural gas analysis based on the target composition of the mixed gas standard substance and the determined total molar amount of filling; simulating the filling process of each component based on the determined molar components of each component to determine the molar density of each component in the filling container after filling; determining the target filling pressure of each component after filling based on the determined molar density of each component in the filling container; and sequentially filling each component into the filling container according to the determined target filling pressure of each component.

Description

Technical Field

[0001] This invention belongs to the field of natural gas detection technology, specifically relating to a method for filling mixed gas standard substances for natural gas analysis. Background Technology

[0002] In 2018, my country's natural gas consumption reached 281 billion cubic meters. 3 Natural gas trade and measurement both involve natural gas composition analysis. Natural gas mixture standard materials serve as reference benchmarks for natural gas composition analysis; their composition is generally determined based on the actual composition range of natural gas. A reasonable standard material composition is crucial for obtaining accurate analysis results regarding the actual composition of natural gas.

[0003] In the preparation of natural gas mixed gas standard materials using the partial pressure method, the filling amount of each substance needs to be determined according to the predetermined target composition and pressure. In the past, the partial pressure of each substance was generally determined first by Dalton's law of partial pressure (GB / T14070 "Preparation of Mixed Gases for Gas Analysis Calibration - Pressure Method"), and then the filling amount of the substance was roughly determined according to the volume of the filling container. Since Dalton's law of partial pressure is only applicable to ideal gases, its application to high-pressure real gases will result in a large deviation. As a result, the composition of the final natural gas mixed gas standard material usually deviates from the predetermined target value. This is not conducive to producing a standard gas with a composition completely consistent with the target composition and has a certain impact on the accurate analysis of the actual natural gas composition. Summary of the Invention

[0004] The purpose of this invention is to provide a method for filling a mixed gas standard substance for natural gas composition analysis, which facilitates the accurate matching of the composition of the natural gas mixed gas standard substance and the container pressure with the preset target value after filling, thereby improving the accuracy of subsequent natural gas analysis.

[0005] To achieve the above objectives, the present invention provides a method for filling a mixed gas standard substance for natural gas analysis, wherein the method includes:

[0006] The total molar amount of the standard material is determined based on the mixed gas standard material used for natural gas analysis;

[0007] Based on the target composition of the mixed gas standard material for natural gas analysis and the determined total molar amount of the filling, the molar component of each component in the mixed gas standard material for natural gas analysis is determined.

[0008] Based on the determined molar components of each component, the filling process of each component is simulated to determine the molar density of each component in the filling container after filling.

[0009] Based on the determined molar density of each component substance in the filling container after filling, the target filling pressure of each component substance after filling is determined.

[0010] Based on the target filling pressure determined for each component, the components are sequentially filled into the filling container.

[0011] The beneficial effects of the above-mentioned filling method for mixed gas standard materials used in natural gas analysis are: (1) By determining the molar density of the natural gas mixture and the molar components of each substance and the target filling pressure under the target conditions, the molar components of each substance or the container pressure after filling each substance can be accurately controlled, so as to achieve the precise consistency between the final filling composition and pressure of the natural gas mixture and the preset target composition and pressure; (2) This filling method is conducive to the accurate preparation of natural gas mixed gas standard materials, ensuring the accurate analysis of the actual natural gas composition, improving the accuracy of natural gas composition analysis, and making the effect of natural gas analysis better.

[0012] In the above-described method for filling mixed gas standard materials for natural gas analysis, preferably, determining the total molar amount of the standard material based on the mixed gas standard material for natural gas analysis includes:

[0013] Establish the gas state equation for mixed gas standard materials used in natural gas analysis;

[0014] The target composition, target pressure, filling temperature, and filling container volume of the mixed gas standard material for natural gas analysis are set, and the target molar density of the mixed gas standard material for natural gas analysis is determined in conjunction with the gas equation of state.

[0015] The total molar amount of the mixed gas standard material used for natural gas analysis is determined based on the volume of the filling container and the target molar density.

[0016] This preferred technical solution is beneficial for determining the total molar amount of mixed gas standard substances used in natural gas analysis.

[0017] In the above-mentioned method for filling mixed gas standard materials for natural gas analysis, preferably, the filling temperature is the ambient temperature or the actual filling temperature determined taking into account the temperature change during the filling process.

[0018] In the above-described method for filling mixed gas standard materials for natural gas analysis, preferably, the determination of the total molar amount of the mixed gas standard material for natural gas analysis based on the volume of the filling container and the target molar density is performed using the following formula:

[0019] n total =ρ mol ·V

[0020] Where, ntotal ρ represents the total molar quantity, mole; V represents the volume of the filling container, L; ρ mol The target molar density is expressed in moles / L.

[0021] This preferred technical solution is beneficial for determining the total molar amount of mixed gas standard substances used in natural gas analysis.

[0022] In the above-mentioned filling method for mixed gas standard materials used for natural gas analysis, preferably, the gas equation of state is the GERG-2008 equation, the AGA-8-92DC equation, the Soave-Redlich-Kwong equation, the Peng-Robinson gas equation of state, the BWR gas equation of state, or the MBWR gas equation of state; more preferably, the gas equation of state is the GERG-2008 equation, the AGA-8-92DC equation, or the Soave-Redlich-Kwong equation;

[0023] This preferred technical solution is beneficial for determining the total molar amount of mixed gas standard substances used in natural gas analysis.

[0024] In the above-described method for filling a mixed gas standard substance for natural gas analysis, preferably, the molar component of each component in the mixed gas standard substance for natural gas analysis is determined according to the target composition of the mixed gas standard substance for natural gas analysis and the determined total molar amount of the filling, in the following manner:

[0025] Using the target composition, filling temperature, and target pressure of the mixed gas standard material for natural gas analysis, the molar density of the target mixed gas standard material is calculated. The product of this density value and the volume of the filling container is the total molar amount of the filling. Then, the target composition is multiplied by the total molar amount of the filling to obtain the molar component of each component in the mixed gas standard material used for natural gas analysis.

[0026] In the above-mentioned method for filling mixed gas standard substances for natural gas analysis, preferably, based on the determined molar components of each component, the filling process of each component is simulated, and the molar density of each component in the filling container after filling is calculated using the following formula:

[0027]

[0028] Where, n j ρ is the molar component of substance j, mole; V is the volume of the container, L; mol,j Let the molar density of the substance in the filling container after the j-th component is filled be moles / L;

[0029] This preferred technical solution is beneficial for accurately calculating the molar density of each substance.

[0030] In the above-mentioned method for filling mixed gas standard materials for natural gas analysis, preferably, the step of determining the target filling pressure of each component material after filling based on the determined molar density of each component material in the filling container after filling includes:

[0031] Based on the determined molar density of each component substance in the filling container after filling, the target composition of the mixed gas standard material for natural gas analysis, the filling temperature and the volume of the filling container, and in conjunction with the gas state equation, the target filling pressure of each component substance after filling is determined.

[0032] This preferred technical solution is beneficial for accurately calculating the target filling pressure of each component after filling, which can be used as a reference standard during actual filling.

[0033] In the above-mentioned method for filling the mixed gas standard material for natural gas analysis, preferably, the method of sequentially filling each component into the filling container according to the determined target filling pressure after filling each component includes:

[0034] The filling process of each component material monitors the real-time pressure of the filling container, i.e. the material filling pressure, until the material filling pressure is the same as the target filling pressure of the corresponding component material, and then the filling of the next material begins, until the filling of all components material is completed.

[0035] This preferred technical solution facilitates the control of the filling amount of each substance through pressure parameters, making the filling process of mixed substances more convenient and improving filling accuracy.

[0036] In the above-mentioned method for filling the mixed gas standard material for natural gas analysis, preferably, during the process of sequentially filling each component into the filling container, each component is filled into the filling container one by one in order of boiling point from high to low.

[0037] This preferred technical solution facilitates the convenient filling of high-boiling-point substances. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort:

[0039] Figure 1 This is a schematic flowchart illustrating a method for filling a mixed gas standard substance for natural gas analysis according to an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0041] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0042] See Figure 1 An embodiment of the present invention provides a method for filling a mixed gas standard substance for natural gas analysis, the method comprising:

[0043] Step S1: Determine the total molar amount of the standard substance to be filled based on the mixed gas standard substance used for natural gas analysis;

[0044] Step S2: Based on the target composition of the mixed gas standard material for natural gas analysis and the determined total molar amount of the filling, determine the molar component of each component in the mixed gas standard material for natural gas analysis.

[0045] Step S3: Based on the determined molar components of each component, simulate the filling process of each component and determine the molar density of each component in the filling container after filling.

[0046] Step S4: Determine the target filling pressure for each component material after filling, based on the determined molar density of the material in the filling container after filling.

[0047] Step S5: Based on the target filling pressure of each component after filling, fill each component into the filling container in sequence.

[0048] Furthermore, step S1 includes:

[0049] Step S11: Establish the gas state equation for the mixed gas standard material used for natural gas analysis;

[0050] Step S12: Set the target composition, target pressure, filling temperature, and filling container volume of the mixed gas standard material for natural gas analysis, and determine the target molar density of the mixed gas standard material for natural gas analysis in conjunction with the gas state equation.

[0051] Step S13: Determine the total molar amount of the mixed gas standard material used for natural gas analysis based on the volume of the filling container and the target molar density;

[0052] Furthermore, the gas equation of state is the GERG-2008 equation, the AGA-8 equation, the Soave-Redlich-Kwong equation, the Peng-Robinson gas equation of state, the BWR gas equation of state, or the MBWR gas equation of state; in one specific embodiment, the gas equation of state is the GERG-2008 equation, the AGA-8 equation, or the Soave-Redlich-Kwong equation.

[0053] The specific expressions and usage methods of the gas state equation GERG-2008 can be found in accordance with conventional practices in this field, such as referring to International Organization for Standardization. ISO 20765-2: Natural gas - Calculation of thermodynamic properties - Part 2: Single-phase properties (gas, liquid, and dense fluid) for extended ranges of application, 2014; the specific expressions and usage methods of the gas state equation AGA-8-92DC can be found in accordance with conventional practices in this field, such as referring to Starling KE, Savidge J L. Compressibility Factors of Natural Gas and Other Related Hydrocarbon Gases [R]. Arlington, VA: American Gas Association, 1992; the specific expressions and usage methods of the gas state equation Soave-Redlich-Kwong can be found in accordance with conventional practices in this field, such as referring to Soave G. Equilibrium constants from a modified Redlich-Kwong equation of state [J]. Chemical Engineering. Science, 1972, 27(6): 1197-1203; The specific expressions and usage methods of the Peng-Robinson gas law equation can be found in the conventional methods of this field, for example, Peng DY, Robinson D BA New Two-Constant Equation of State[J]. Industrial & Engineering Chemistry Research, 1976, 15(1): 59-64; The specific expressions and usage methods of the BWR or MBWR gas law equation can be found in the conventional methods of this field, for example, Jacobsen RT, Stewart RB. Thermodynamic Properties of Nitrogen Including Liquid and Vapor Phases from 63K to 2000K with Pressures to 10,000Bar[J].Journal of Physical and Chemical Reference data,1973,2(4):757-922;.

[0054] Furthermore, step S13 is performed using the following formula:

[0055] n total =ρ mol ·V

[0056] Where, n total ρ represents the total molar quantity, mole; V represents the volume of the filling container, L; ρ mol The target molar density is expressed in moles / L.

[0057] Furthermore, the filling temperature is the ambient temperature or the actual filling temperature determined taking into account temperature changes during the filling process.

[0058] Furthermore, the molar density of each component substance in the filling container after filling in step S3 is calculated using the following formula:

[0059]

[0060] Where, n j ρ is the molar component of substance j, mole; V is the volume of the container, L; mol,j Let be the molar density of the substance in the filling container after the j-th component is filled, in moles / L.

[0061] Furthermore, step S2 is implemented in the following manner:

[0062] Using the target composition, filling temperature, and target pressure of the mixed gas standard material for natural gas analysis, the molar density of the target mixed gas standard material is calculated. The product of this density value and the volume of the filling container is the total molar amount of the filling. Then, the target composition is multiplied by the total molar amount of the filling to obtain the molar component of each component in the mixed gas standard material used for natural gas analysis.

[0063] Furthermore, step S4 includes:

[0064] Based on the determined molar density of each component in the filling container after filling, the target composition of the mixed gas standard material for natural gas analysis, the filling temperature, and the volume of the filling container, the target filling pressure of each component after filling is determined in conjunction with the gas equation of state.

[0065] Furthermore, step 5 includes:

[0066] During the filling process of each component, the real-time pressure of the filling container, i.e. the filling pressure of the component, is monitored until the filling pressure of the component is the same as the target filling pressure of the corresponding component. Then the filling of the next component begins until all components are filled.

[0067] Furthermore, during the process of sequentially filling the filling container with each component, the components are filled into the filling container one by one in order of decreasing boiling point.

[0068] Example 1

[0069] This embodiment provides a method for filling a mixed gas standard substance for natural gas analysis, including the following steps:

[0070] S1. Determine the total molar amount of the standard substance based on the mixed gas standard substance used for natural gas analysis, specifically including the following steps:

[0071] S11. Establish the Soave-Redlich-Kwong equation of state for mixed gas standard materials used in natural gas analysis; wherein, the Soave-Redlich-Kwong equation of state is a known existing equation of state;

[0072] S12. Set the target composition, target pressure, filling temperature and filling container volume of the mixed gas standard material for natural gas analysis, and determine the target molar density of the mixed gas standard material for natural gas analysis in conjunction with the gas state equation in step S11.

[0073] S13. Based on the volume of the filling container and the target molar density, the total molar amount of the mixed gas standard material used for natural gas analysis is determined using the following formula;

[0074] n total =ρ mol ·V

[0075] Where, n total ρ represents the total molar quantity, mole; V represents the volume of the filling container, L; ρ mol The target molar density is expressed in moles / L.

[0076] S2. Based on the target composition of the mixed gas standard material for natural gas analysis and the total molar amount obtained in step S1, determine the molar component of each component in the mixed gas standard material for natural gas analysis, specifically including the following steps:

[0077] Using the target composition, filling temperature, and target pressure of the mixed gas standard material for natural gas analysis, the molar density of the target mixed gas standard material is calculated. The product of this density value and the volume of the filling container is the total molar amount of the filling. Then, the target composition is multiplied by the total molar amount of the filling to obtain the molar component of each component in the mixed gas standard material used for natural gas analysis.

[0078] S3. Based on the molar components of each component determined in step S2, simulate the filling process of each component to determine the molar density of each component in the filling container after filling; specifically, the following formula is used for calculation:

[0079]

[0080] Where, n j ρ is the molar component of substance j, mole; V is the volume of the container, L; mol,j Let be the molar density of the substance in the filling container after the j-th component is filled, in moles / L.

[0081] S4. Based on the molar density of each component substance in the filling container after filling, determined in step S3, as well as the target composition of the mixed gas standard substance for natural gas analysis, the filling temperature, and the volume of the filling container, and combined with the Soave-Redlich-Kwong equation of gas state described in step S11, determine the target filling pressure of each component substance after filling.

[0082] S5. Based on the target filling pressure of each component determined in step S4, fill each component into the filling container one by one in order of boiling point from high to low. When filling each component, detect the real-time pressure of the filling container to obtain the filling pressure of the component. When the filling pressure of the component is the same as the target filling pressure of the corresponding component, start filling the next component until the filling is completed. During the process, if the filling pressure of a component is less than the target filling pressure of the component, continue filling the component.

[0083] The gas state equation can also be the Peng-Robinson gas state equation, the BWR gas state equation, or the MBWR gas state equation.

[0084] Example 2

[0085] This embodiment provides a method for filling a mixed gas standard substance for natural gas analysis, including the following steps:

[0086] S1. Determine the total molar amount of the standard substance based on the mixed gas standard substance used for natural gas analysis, specifically including the following steps:

[0087] S11. Establish the gas state equation AGA-8-92DC equation for mixed gas standard materials used in natural gas analysis; wherein, the gas state equation AGA-8-92DC equation is a known existing equation of state;

[0088] S12. Set the target composition, target pressure, filling temperature and filling container volume of the mixed gas standard material for natural gas analysis, and determine the target molar density of the mixed gas standard material for natural gas analysis in conjunction with the gas state equation in step S11.

[0089] S13. Based on the volume of the filling container and the target molar density, the total molar amount of the mixed gas standard material used for natural gas analysis is determined using the following formula;

[0090] n total =ρ mol ·V

[0091] Where, n total ρ represents the total molar quantity, mole; V represents the volume of the filling container, L; ρ mol The target molar density is expressed in moles / L.

[0092] S2. Based on the target composition of the mixed gas standard material for natural gas analysis and the total molar amount obtained in step S1, determine the molar component of each component in the mixed gas standard material for natural gas analysis, specifically including the following steps:

[0093] Using the target composition, filling temperature, and target pressure of the mixed gas standard material for natural gas analysis, the molar density of the target mixed gas standard material is calculated. The product of this density value and the volume of the filling container is the total molar amount of the filling. Then, the target composition is multiplied by the total molar amount of the filling to obtain the molar component of each component in the mixed gas standard material used for natural gas analysis.

[0094] S3. Based on the molar components of each component determined in step S2, simulate the filling process of each component to determine the molar density of each component in the filling container after filling; specifically, the following formula is used for calculation:

[0095]

[0096] Where, n j ρ is the molar component of substance j, mole; V is the volume of the container, L; mol,j Let be the molar density of the substance in the filling container after the j-th component is filled, in moles / L.

[0097] S4. Based on the molar density of each component substance in the filling container after filling, determined in step S3, as well as the target composition of the mixed gas standard substance for natural gas analysis, the filling temperature, and the volume of the filling container, and in conjunction with the gas state AGA-8-92DC equation described in step S11, determine the target filling pressure of each component substance after filling.

[0098] S5. Based on the target filling pressure of each component determined in step S4, fill each component into the filling container one by one in order of boiling point from high to low. When filling each component, detect the real-time pressure of the filling container to obtain the filling pressure of the component. When the filling pressure of the component is the same as the target filling pressure of the corresponding component, start filling the next component until the filling is completed. During the process, if the filling pressure of a component is less than the target filling pressure of the component, continue filling the component.

[0099] Example 3

[0100] This embodiment provides a method for filling a mixed gas standard substance for natural gas analysis, including the following steps:

[0101] S1. Determine the total molar amount of the standard substance based on the mixed gas standard substance used for natural gas analysis, specifically including the following steps:

[0102] S11. Establish the GERG-2008 equation of state for mixed gas standard materials used in natural gas analysis; wherein, the GERG-2008 equation of state is a known existing equation of state;

[0103] S12. Set the target composition, target pressure, filling temperature and filling container volume of the mixed gas standard material for natural gas analysis, and determine the target molar density of the mixed gas standard material for natural gas analysis in conjunction with the gas state equation in step S11.

[0104] S13. Based on the volume of the filling container and the target molar density, the total molar amount of the mixed gas standard material used for natural gas analysis is determined using the following formula;

[0105] n total =ρ mol ·V

[0106] Where, n total ρ represents the total molar quantity, mole; V represents the volume of the filling container, L; ρ mol The target molar density is expressed in moles / L.

[0107] S2. Based on the target composition of the mixed gas standard material for natural gas analysis and the total molar amount obtained in step S1, determine the molar component of each component in the mixed gas standard material for natural gas analysis, specifically including the following steps:

[0108] Using the target composition, filling temperature, and target pressure of the mixed gas standard material for natural gas analysis, the molar density of the target mixed gas standard material is calculated. The product of this density value and the volume of the filling container is the total molar amount of the filling. Then, the target composition is multiplied by the total molar amount of the filling to obtain the molar component of each component in the mixed gas standard material used for natural gas analysis.

[0109] S3. Based on the molar components of each component determined in step S2, simulate the filling process of each component to determine the molar density of each component in the filling container after filling; specifically, the following formula is used for calculation:

[0110]

[0111] Where, n j ρ is the molar component of substance j, mole; V is the volume of the container, L; mol,j Let be the molar density of the substance in the filling container after the j-th component is filled, in moles / L.

[0112] S4. Based on the molar density of each component substance in the filling container after filling, determined in step S3, the target composition of the mixed gas standard substance for natural gas analysis, the filling temperature, and the volume of the filling container, and in conjunction with the gas state GERG-2008 equation described in step S11, determine the target filling pressure of each component substance after filling.

[0113] S5. Based on the target filling pressure of each component determined in step S4, fill each component into the filling container one by one in order of boiling point from high to low. When filling each component, detect the real-time pressure of the filling container to obtain the filling pressure of the component. When the filling pressure of the component is the same as the target filling pressure of the corresponding component, start filling the next component until the filling is completed. During the process, if the filling pressure of a component is less than the target filling pressure of the component, continue filling the component.

[0114] Experimental Example 1

[0115] In this experiment, a binary gas mixture of 95% methane and 5% ethane was used. The filling bottle volume was 4.1L and the filling temperature was 20℃. The traditional partial pressure filling method and the filling method of Example 1 were used for comparison. The specific results are shown in Table 1 and Table 2 below.

[0116] Table 1 shows the filling results of Experiment 1 using the traditional pressure-dividing filling method.

[0117]

[0118] As shown in Table 1, the traditional filling process generally first calculates the partial pressure of each substance based on Dalton's law of partial pressures, and then determines the container pressure after filling different substances as a control parameter to control the filling amount. The table above shows the theoretical filling mass of methane and ethane, the theoretical composition of the mixture after filling, and the relative deviation from the target composition under different target filling pressures for the traditional partial pressure method of filling a binary gas mixture of methane and ethane. It can be seen that the higher the target pressure, the greater the deviation between the theoretical composition and the target composition of the traditional filling method. The deviation is significant for components with relatively low content. For example, when the target filling pressure is 10 MPa, the deviation between the theoretical filling composition and the target filling composition of ethane can reach -14.37%.

[0119] Table 2 shows the filling results of Experiment 1 using the filling method of Example 1.

[0120]

[0121]

[0122] As can be seen from Table 2, when using the filling method of Example 1 to fill the binary gas mixture of methane and ethane, the theoretical filling mass of methane and ethane, the theoretical composition of the mixture after filling, and the relative deviation from the target composition are shown in Table 2 under different target filling pressures. Theoretically, the composition of the mixed gas obtained by this filling method has no deviation from the target composition.

[0123] Experimental Example 2

[0124] This experiment used a ternary gas mixture of 90% methane, 8% ethane, and 2% propane, filled into a 4.1L bottle at a filling temperature of 20°C. The traditional partial pressure filling method and the filling method of Example 1 were compared, and the specific results are shown in Tables 3 and 4 below.

[0125] Table 3 shows the filling results of Experiment 2 using the traditional pressure-dividing filling method.

[0126]

[0127] As can be seen from Table 3, the higher the target pressure, the greater the deviation between the theoretical composition and the target composition of the traditional filling method. The deviation is significant for components with relatively low content. Specifically, when the target filling pressure is 10 MPa, the deviation between the theoretical filling composition and the target filling composition of propane and ethane can reach -17.80% and -10.17%, respectively.

[0128] Table 4 shows the filling results of Experiment 2 using the filling method of Example 1.

[0129]

[0130]

[0131] As can be seen from Table 4, when the mixed gas is filled using the filling method of Example 1, the theoretical filling mass of different gases, the theoretical composition of the mixed gas after filling, and the relative deviation from the target composition are shown in the table above under different target filling pressures. Theoretically, the mixed gas composition obtained by this filling method has no deviation from the target composition.

[0132] Experimental Example 3

[0133] In this experimental example, the actual natural gas standard material (thirteen-element mixture) was filled in a 4.1L bottle at a filling temperature of 20℃. The composition of the natural gas mixture standard material (thirteen-element mixture) is shown in Table 5 below:

[0134] Table 5 shows the composition of natural gas standard materials (thirteen-element mixture).

[0135] helium hydrogen oxygen nitrogen carbon dioxide Ethane propane 0.1399 0.1399 0.1548 2.9971 3.097 2.9971 0.6134 Isobutane n-Butane isopentane n-Pentane n-Hexane methane 0.1958 0.2008 0.1119 0.1489 0.0849 89.1186

[0136] The traditional pressure-dividing filling method and the filling method of this embodiment 1 were compared and filled respectively. The specific results are shown in Tables 6 and 7 below.

[0137] Table 6 shows the filling results of Experiment 3 using the traditional pressure-dividing filling method.

[0138]

[0139]

[0140]

[0141] As can be seen from Table 6, the higher the target pressure, the greater the deviation between the theoretical composition and the target composition of the traditional filling method. The deviation is significant for components with relatively low content. Specifically, when the target filling pressure is 10 MPa, the deviation between the theoretical filling composition and the target composition of methane is 1.66%, and the filling composition of other substances is greater than -10%, with the relative deviation of helium (trace amount) reaching as high as -27.09%.

[0142] Table 7 shows the filling results of Experiment 3 using the filling method of Example 1.

[0143]

[0144]

[0145]

[0146] As can be seen from Table 7, when the mixed gas is filled using the filling method of Example 1, the theoretical filling mass of different gases, the theoretical composition of the mixed gas after filling, and the relative deviation from the target composition are shown in the table above under different target filling pressures. Theoretically, the mixed gas composition obtained by this filling method has no deviation from the target composition.

[0147] 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 principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for filling a mixed gas standard substance for natural gas analysis, wherein, The method includes: Establish a gas equation of state for a mixed gas standard material used for natural gas analysis; wherein the gas equation of state is the GERG-2008 equation, the AGA-8-92DC equation, the Soave-Redlich-Kwong equation, the Peng-Robinson gas equation of state, the BWR gas equation of state, or the MBWR gas equation of state. The target composition, target pressure, filling temperature, and filling container volume of the mixed gas standard material for natural gas analysis are set, and the target molar density of the mixed gas standard material for natural gas analysis is determined in conjunction with the gas equation of state. The total molar amount of the mixed gas standard material used for natural gas analysis is determined based on the volume of the filling container and the target molar density. Based on the target composition of the mixed gas standard material for natural gas analysis and the determined total molar amount of the filling, the molar component of each component in the mixed gas standard material for natural gas analysis is determined. Based on the determined molar components of each component, the filling process of each component is simulated to determine the molar density of each component in the filling container after filling. Based on the determined molar density of each component substance in the filling container after filling, the target composition of the mixed gas standard material for natural gas analysis, the filling temperature and the volume of the filling container, and in conjunction with the gas state equation, the target filling pressure of each component substance after filling is determined. Based on the target filling pressure determined for each component, the components are sequentially filled into the filling container.

2. The method according to claim 1, wherein, The total molar amount of the mixed gas standard material used for natural gas analysis is determined according to the volume of the filling container and the target molar density using the following formula: in, n total Total mole; V Volume (L) of the filling container; ρ mol The target molar density (mole / L).

3. The method according to claim 1, wherein, The gas state equation is either the GERG-2008 equation, the AGA-8-92DC equation, or the Soave-Redlich-Kwong equation.

4. The method according to claim 1, wherein, Based on the target composition of the mixed gas standard material for natural gas analysis and the determined total molar amount of the filling, the molar component of each component in the mixed gas standard material for natural gas analysis is determined in the following manner: Multiply the target composition by the total molar amount of the filling to obtain the molar components of each component in the mixed gas standard material used for natural gas analysis.

5. The method according to claim 1, wherein, The filling temperature is the ambient temperature or the actual filling temperature determined taking into account temperature changes during the filling process.

6. The method according to claim 1, wherein, Based on the determined molar components of each component, the filling process of each component is simulated, and the molar density of each component in the filling container after filling is calculated using the following formula: in, n j Let be the mole component of the j-th constituent substance. V Volume (L) of the filling container; ρ mol,j The molar density (mole / L) of the substance in the filling container after the j-th component is filled.

7. The method according to claim 1, wherein, Based on the determined target filling pressure for each component, the components are sequentially filled into the filling container, including: During the filling process of each component, the real-time pressure of the filling container, i.e. the filling pressure of the component, is monitored until the filling pressure of the component is the same as the target filling pressure of the corresponding component. Then the filling of the next component begins until all components are filled.

8. The method according to claim 1, wherein, During the process of sequentially filling the filling container with each component, the components are filled into the filling container one by one in order of decreasing boiling point.

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