Decarburization method, system and equipment based on improved PR state equation and medium

Abstract

The invention relates to the technical field of decarburization, and discloses a decarburization method, system, equipment and medium based on an improved PR state equation, and the decarburization method comprises the following steps: S1, introducing a correction coefficient x based on a gravitation parameter of an original PR state equation to obtain an improved PR state equation, and obtaining the CO2 content in CO2-containing natural gas according to a chromatographic analysis instrument, meanwhile, a comparison temperature and a comparison pressure are obtained according to the working state temperature and the working state pressure, a correction coefficient x is obtained according to the CO2 content, the comparison temperature and the comparison pressure, and finally an improved PR state equation is obtained; s2, measuring the working state temperature and the working state pressure of the CO2-containing natural gas when the CO2-containing natural gas enters the decarburization equipment; s3, according to the working state temperature and the working state pressure measured in the S2, the natural gas volume flow under the CO2-containing working condition is calculated based on the improved PR state equation; and S4, determining the circulating flow of the decarburization solvent according to the volume flow obtained in S3. According to the invention, the metering accuracy of the natural gas with high CO2 content is improved.

Description

Technical Field

[0001] The invention relates to the technical field of decarburization, and in particular to a decarburization method, system, equipment and medium based on an improved PR state equation. Background Art

[0002] In the surface gathering and transportation of high-CO2 natural gas fields, due to the difference in the circulation flow rate of the decarbonization solvent when the gathering and transportation stations treat high-CO2 natural gas with different processing volumes, it is necessary to accurately measure the high-CO2 natural gas. At present, differential pressure flowmeters are mostly used for volume flow measurement in gathering and transportation. The key to accurate measurement of high-CO2 natural gas is the accurate calculation of physical parameters such as density and viscosity. The state equation is an important tool for calculating the basic thermophysical parameters such as density and viscosity of CO2 and high-CO2 natural gas, and is the basis for accurate measurement. At present, typical CO2 state equations include the BWRS state equation proposed in 1970, the RKS state equation proposed in 1972, the PR state equation proposed in 1976, the LKP state equation proposed in 1982, the SW-1996 state equation proposed in 1996, and the GERG-2004 state equation proposed in 2007. Among them, RKS and PR state equations are cubic state equations, which are usually used to calculate the physical properties of gas-phase CO2; BWRS state equation and LKP state equation are multi-parameter state equations, which are used to calculate the physical properties of gas-phase or liquid-phase CO2; SW-1996 and GERG-2004 state equations are both non-analytical state equations, which can be solved by Helmholtz free energy and can be used to calculate the physical properties of CO2 in gas-phase, liquid-phase, near-critical, supercritical and saturation line states. The above equations all require relevant parameters to be measured experimentally, so they have strict requirements for the scope of application and are no longer accurate after exceeding their applicable scope.

[0003] Due to the current limitations of the application scope of the state equation, the calculation of physical parameters of high CO2 content under complex working conditions in the gathering and transportation station is not accurate enough, and the differential pressure flow meter produces large errors in measurement. Therefore, a state equation that can accurately calculate the physical parameters of high CO2 content is needed. However, there is currently no more accurate state equation to describe its physical parameters. Studies have shown that when the CO2 content is higher than 50%, the deviation between the compression factor calculated using the cubic state equation and the actual value can be as high as 5% to 40%. Summary of the invention

[0004] The present invention provides a decarbonization method, system, equipment and medium based on an improved PR state equation, which makes the method more suitable for the working conditions of high-CO2 natural gas by correcting the gravitational term coefficient in the compression factor calculation formula, improves the metering accuracy of high-CO2 natural gas, and optimizes the processing technology of gathering and transportation stations.

[0005] The present invention is achieved through the following technical solutions:

[0006] A decarburization method based on an improved PR state equation comprises:

[0007] S1. Based on the gravity parameter of the original PR state equation, a correction coefficient x is introduced to obtain an improved PR state equation, and the CO2 content in the CO2-containing natural gas is obtained according to the chromatographic analysis instrument. At the same time, the comparative temperature and comparative pressure are obtained according to the working state temperature and the working state pressure, and the correction coefficient x is obtained according to the CO2 content, the comparative temperature and the comparative pressure, and finally the improved PR state equation is obtained;

[0008] S2. Measure the working temperature and working pressure of the CO2-containing natural gas when it enters the decarbonization equipment;

[0009] S3, according to the working state temperature and working state pressure measured by S2, the natural gas volume flow rate under the CO2-containing working condition is calculated based on the improved PR state equation;

[0010] S4. Determine the circulation flow rate of the decarbonization solvent according to the volume flow rate obtained in S3.

[0011] As an optimization, in S1, the specific process of introducing the correction coefficient x based on the gravity parameter of the original PR state equation to obtain the improved PR state equation is: introducing the correction coefficient x into the gravity term a in the original PR state equation, and correlating the comparison temperature, comparison pressure and the correction coefficient x, and finally obtaining the improved PR state equation.

[0012] As an optimization, the original PR state equation is:

[0013]

[0014]

[0015]

[0016]

[0017]

[0018] Among them, Z is the compression factor, ω is the eccentricity factor, P c is the critical pressure of the gas, in kPa, T c is the critical temperature of the gas, in K, R is the gas constant, 8.314 kJ / (kmol·K), a is the gravitational parameter, b is the volume term, T is the working temperature of the gas, A, B, α are the first intermediate parameter, the second intermediate parameter and the third intermediate parameter respectively, and P is the working pressure of the gas, in Kpa.

[0019] As an optimization, the specific process of obtaining the correction coefficient x by CO2 content, contrast temperature and contrast pressure is as follows:

[0020] S1.1. Introduce a correction coefficient x into the third intermediate parameter α of the gravity parameter a, that is:

[0021]

[0022] S1.2. Compress several groups of natural gas containing CO2, measure several groups of compression factors, and use the compression factors Z k Substituting into equation (1) and taking the sum of squares, we get equation (7) and equation (8):

[0023]

[0024]

[0025] Where M is the total number of experimental data, that is, the total number of compression factors; Z k is the compression factor value of the kth group; P k is the pressure corresponding to the kth group of compression factor values, in MPa; T k is the temperature corresponding to the kth group of compression factor values, in K; f is the accuracy function; A k , B k are the first intermediate parameter and the second intermediate parameter of the kth group respectively; ci is the critical pressure of component i, in kPa; T ci is the critical temperature of component i, in K; y i is the molar content of the gas of component i; R is the gas constant, 8.314 kJ / (kmol·K);

[0026] S1.3. All corresponding correction parameters are calculated based on multiple sets of experimental data. By comparing the correction coefficient with the contrast temperature and contrast pressure, the general expression of the correction parameter x is explored using the nonlinear data fitting method, and the general expression of the correction parameter x is simplified, and finally the following formula is obtained:

[0027]

[0028]

[0029] Among them, U1 is the fourth intermediate parameter, T r is the comparison temperature, x is the correction factor, f ω The relative molecular weight of the gas;

[0030] S1.4. U1 is calculated based on the CO2 content, comparative temperature and comparative pressure, thereby obtaining the correction parameter x under different CO2 contents, and finally obtaining the improved PR state equation.

[0031] As an optimization, the specific process of obtaining the fourth intermediate parameter k1 is:

[0032] S1.4.1, respectively, the experimental data of CO2 content of 9.84%, 28.86%, 50.99%, 70.98%, 91.77% and 100% are fitted in combination with the contrast temperature and contrast pressure and the CO2 content is introduced to obtain the following equation:

[0033]

[0034] Among them, U1 is the fourth intermediate parameter, p1~p4 are four intermediate sub-parameters, P r is the contrast pressure, T r is the contrast temperature, y is the molar content of CO2;

[0035] S1.4.2. Solve the four intermediate sub-parameters p1 to p4 by nonlinear fitting method, and finally calculate the fourth intermediate parameter U1 according to the comparison of temperature, pressure and CO2 content.

[0036] As an optimization, the process of S3 is to calculate the compression factor Z of the working state of natural gas containing CO2 based on the improved PR state equation, and finally apply the compression factor Z to the differential pressure flowmeter to calculate the volume flow under the working condition containing CO2:

[0037]

[0038] Among them, Q v is the volume flow rate in working state, in m 3 / h;Q n is the volume flow rate under standard conditions, in m 3 / h; P n is the standard pressure, 1.013MPa; P is the working pressure, in MPa; T n is the standard state temperature, 293.15K; T is the working state temperature, unit is K; Z n is the compression factor of the standard state, dimensionless; Z is the compression factor of the working state, dimensionless.

[0039] As an optimization, the formulas for the comparative pressure and comparative temperature are:

[0040]

[0041]

[0042] Among them, P r is the relative pressure of the gas, dimensionless; T r is the relative temperature of the gas, dimensionless; P is the working pressure of the gas, in MPa; P c is the critical pressure; T is the working temperature of the gas, in K; T c is the critical temperature.

[0043] The present invention also discloses a decarbonization system based on an improved PR state equation, comprising:

[0044] An equation building module is used to introduce a correction coefficient x based on the gravity parameter of the original PR state equation to obtain an improved PR state equation, and obtain the CO2 content in the CO2-containing natural gas according to the chromatographic analysis instrument, and obtain the comparative temperature and comparative pressure according to the working state temperature and the working state pressure, and obtain the correction coefficient x according to the CO2 content, comparative temperature and comparative pressure, and finally obtain the improved PR state equation;

[0045] The measurement module is used to measure the working temperature and working pressure of the CO2-containing natural gas when it enters the decarbonization equipment;

[0046] A volume flow calculation module, used to calculate the volume flow of natural gas under CO2-containing conditions based on the improved PR state equation according to the working state temperature and working state pressure measured by the measurement module;

[0047] The decarbonization solvent circulation flow calculation module determines the decarbonization solvent circulation flow according to the volume flow obtained by the volume flow calculation module.

[0048] The present invention also discloses an electronic device, comprising at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute a decarbonization method based on an improved PR state equation as described above.

[0049] The present invention also discloses a storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the aforementioned decarburization method based on an improved PR state equation.

[0050] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0051] The present invention corrects the gravitational term coefficient in the compression factor calculation formula to make it more suitable for the working conditions of high-CO2-content natural gas, improves the metering accuracy of high-CO2-content natural gas, and optimizes the processing technology of the gathering and transportation station. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0053] Figure 1 Comparison chart of 9.84% CO2 natural gas compression factor calculated by PR state equation before and after improvement and experimental value;

[0054] Figure 2 Comparison of the 28.66% CO2 natural gas compression factor calculated by the PR state equation before and after improvement and the experimental value

[0055] Figure 3 Comparison chart of 50.99% CO2 natural gas compression factor calculated by PR state equation before and after improvement and experimental value;

[0056] Figure 4 Comparison chart of 70.98% CO2 natural gas compression factor calculated by PR state equation before and after improvement and experimental value;

[0057] Figure 5 Comparison chart of 91.77% CO2 natural gas compression factor calculated by PR state equation before and after improvement and experimental value;

[0058] Figure 6 Comparison chart of 100% CO2 compression factor calculated by PR state equation before and after improvement and experimental value. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0060] The compression factor is the basis for calculating basic parameters such as natural gas density, compression factor, and fugacity of each component. Therefore, to improve the calculation accuracy of CO2 physical parameters in high-CO2 natural gas, it is necessary to correct certain coefficients in the compression factor calculation formula under high-CO2 conditions. The present invention proposes an improved method for the PR state equation, which corrects the gravity term coefficient in the compression factor calculation formula to make it more suitable for the working conditions of high-CO2 natural gas, improve the metering accuracy of high-CO2 natural gas, and optimize the processing process of gathering and transportation stations.

[0061] A decarburization method based on an improved PR state equation of embodiment 1 comprises:

[0062] S1. Based on the gravity parameter of the original PR state equation, a correction coefficient x is introduced to obtain an improved PR state equation, and the CO2 content in the CO2-containing natural gas is obtained according to the chromatographic analysis instrument. At the same time, the comparative temperature and comparative pressure are obtained according to the working state temperature and the working state pressure, and the correction coefficient x is obtained according to the CO2 content, the comparative temperature and the comparative pressure, and finally the improved PR state equation is obtained;

[0063] In the present invention, the fourth intermediate coefficient U1 of the expression of the correction coefficient x in the PR equation is corrected through 256 sets of experiments, and finally the gravity term coefficient in the PR equation is changed to make the volume measurement result of the differential pressure flowmeter applied to high CO2 content natural gas more accurate.

[0064] The specific process of introducing the correction coefficient x based on the gravity parameter of the original PR state equation to obtain the improved PR state equation is as follows: the correction coefficient x is introduced into the gravity term a in the original PR state equation, and the contrast temperature, contrast pressure and the correction coefficient x are associated to finally obtain the improved PR state equation.

[0065] The original PR state equation is:

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] Among them, Z is the compression factor, ω is the eccentricity factor, P c is the critical pressure of the gas, in kPa, T c is the critical temperature of the gas, in K, R is the gas constant, 8.314 kJ / (kmol·K), a is the gravitational parameter, b is the volume term, T is the working temperature of the gas, A, B, α are the first intermediate parameter, the second intermediate parameter and the third intermediate parameter respectively, and P is the working pressure of the gas, in Kpa.

[0072] The formulas for the comparative pressure and comparative temperature are:

[0073]

[0074]

[0075] Among them, P r is the relative pressure of the gas, dimensionless; T r is the relative temperature of the gas, dimensionless; P is the working pressure of the gas, in MPa; P c is the critical pressure; T is the working temperature of the gas, in K; T c is the critical temperature.

[0076] The specific process of obtaining the correction coefficient x by comparing CO2 content, temperature and pressure is as follows:

[0077] The influence of the introduction of CO2 on the state equation is mainly to change the gravity parameter a in the PR equation. Therefore, the present invention only makes corrections to the gravity parameter and introduces a correction coefficient x into the gravity parameter a, that is:

[0078]

[0079] By substituting the experimental data of the compression factor at each temperature and pressure into formula (6), the corresponding correction coefficient x can be calculated, so x is not a constant.

[0080] If the compression factor calculated by the original PR equation is less than the experimental value, the value of x is less than 1; if the calculated compression factor is greater than the experimental data, the value of x is greater than 1. If all experimental data are substituted into the above formula, only an average value of x can be calculated, which reduces the correction accuracy of the formula. To address this problem, the M value in the following formula can be set to 1, so that an x ​​can be calculated for each experimental data. According to the variation law of x and its related parameters, the function expression of x is further explored. In this way, each calculated value can be corrected to achieve the purpose of correcting the PR state equation.

[0081] According to the experimental value of the compression factor, the method of correcting the PR state equation using the least squares principle is as follows: Suppose there are M groups of compression factor experimental data, and the compression factor Z k Substituting into equation (1) and taking the sum of squares, we can obtain equation (7); if the value of f is closer to 0, the accuracy of the formula is higher.

[0082] S1.2. Compress several groups of natural gas containing CO2, measure several groups of compression factors, and use the compression factors Z k Substituting into equation (1) and taking the sum of squares, we get equation (7) and equation (8):

[0083]

[0084]

[0085] Where M is the total number of experimental data, that is, the total number of compression factors; Zk is the compression factor value of the kth group; P k is the pressure corresponding to the kth group of compression factor values, in MPa; T k is the temperature corresponding to the kth group of compression factor values, in K; f is the accuracy function; A k , B k are the first intermediate parameter and the second intermediate parameter of the kth group respectively; ci is the critical pressure of component i, in kPa; T ci is the critical temperature of component i, in K; y i is the molar content of the gas of component i; R is the gas constant, 8.314 kJ / (kmol·K);

[0086] Based on the comparison principle, when natural gas is in the same comparison temperature and comparison pressure state, its compression factor value is similar. Therefore, the present invention associates the comparison temperature, comparison pressure and correction coefficient x. Based on this idea, all corresponding correction parameters are calculated based on 256 sets of experimental data. By comparing the correction coefficient with the comparison temperature and comparison pressure, the general expression of the correction parameter x is explored using a nonlinear data fitting method, and simplified by an appropriate method, a correction coefficient expression that can be used in practical applications is finally obtained, namely:

[0087] S1.3. All corresponding correction parameters are calculated based on multiple sets of experimental data. By comparing the correction coefficient with the contrast temperature and contrast pressure, the general expression of the correction parameter x is explored using the nonlinear data fitting method, and the general expression of the correction parameter x is simplified, and finally the following formula is obtained:

[0088]

[0089]

[0090] Among them, U1 is the fourth intermediate parameter, T r is the comparison temperature, x is the correction factor, f ω The relative molecular weight of the gas;

[0091] The above equations (9) and (10) are the expressions for calculating the correction coefficient. When the system temperature, pressure and feed composition are given, the T of the state equation is r and f w can be calculated, and the correction parameter x can be obtained from the deviation between the compression factor calculated by the PR state equation and the experimental data. U1 can be determined by the calculated values ​​of the above parameters.

[0092] S1.4. U1 is calculated based on the CO2 content, comparative temperature and comparative pressure, thereby obtaining the correction parameter x under different CO2 contents, and finally obtaining the improved PR state equation.

[0093] The specific process of obtaining the fourth intermediate parameter k1 is:

[0094] The values ​​of S1.4.1 and U1 are related to the contrast temperature, contrast pressure and CO2 content. However, it is difficult to construct the ternary function directly using the nonlinear data fitting method. Therefore, the CO2 content is first taken as a constant, and the experimental data with CO2 contents of 9.84%, 28.86%, 50.99%, 70.98%, 91.77% and 100% are fitted in combination with the contrast temperature and contrast pressure to obtain the following equation:

[0095]

[0096] This formula calculates the U1 value for a given CO2 content very accurately. In order to apply this formula to systems with different CO2 contents, by comparing the fitting equations, the CO2 content term is introduced on the basis of the above formula, and the following equation is obtained:

[0097]

[0098] Among them, U1 is the fourth intermediate parameter, p1~p4 are four intermediate sub-parameters, P r is the contrast pressure, T r is the contrast temperature, y is the molar content of CO2;

[0099] S1.4.2. Solve the four intermediate sub-parameters p1 to p4 by nonlinear fitting method, and finally calculate the fourth intermediate parameter k1 according to the comparison of temperature, pressure and CO2 content.

[0100] As shown in Table 1. The above formula (10) is the calculation formula of the fourth intermediate parameter U1.

[0101] Table 1 Parameter U1 calculation formula intermediate sub-parameters p1~p4 fitting values

[0102]

[0103] In order to further verify the accuracy of the improved PR state equation for the calculation of the compression factor of high CO2 natural gas, the improved PR state equation was used to calculate the compression factor of natural gas under the conditions of CO2 content of 9.84%, 28.86%, 50.99%, 70.98%, 91.77%, and 100%, and the calculated values ​​of the improved PR equation, the calculated values ​​of the original PR equation and the experimental values ​​were compared. In order to analyze the deviation between the calculated value and the experimental value, the average relative deviation is defined as shown in formula (13).

[0104]

[0105] Where AAE is the calculation error, %; N is the number of calculation points; Z cali is the calculated value of the compression factor; Z expi is the experimental value of compression factor;

[0106] Comparison of the calculated and experimental values ​​of the compression factor is shown in the attached figure. Figures 1 to 6 The calculation deviation analysis is shown in Table 2.

[0107] Table 2 Comparison of average relative deviation of compression factor

[0108]

[0109] The calculation results show that the minimum average absolute deviation between the natural gas compression factor calculated by the original PR equation and the experimental value is 4.150%, the maximum is 33.679%, and the total average absolute deviation is 11.688%; the minimum average absolute deviation after improvement is 0.276%, the maximum average absolute deviation is 7.163%, and the total average absolute deviation is 2.708%. The calculation accuracy of the improved PR equation for the compression factor of high CO2 natural gas has been improved by an average of 8.98%.

[0110] S2. Measure the working temperature and working pressure of the CO2-containing natural gas when it enters the decarbonization equipment;

[0111] S3, according to the working state temperature and working state pressure measured by S2, the natural gas volume flow rate under the CO2-containing working condition is calculated based on the improved PR state equation;

[0112] The process of S3 is to calculate the compression factor Z of the working state of natural gas containing CO2 based on the improved PR state equation, and finally apply the compression factor Z to the differential pressure flowmeter to calculate the volume flow under the working condition containing CO2:

[0113]

[0114] Among them, Q v is the volume flow rate in working state, in m 3 / h;Q n is the volume flow rate under standard conditions, in m 3 / h; P n is the standard pressure, 1.013MPa; P is the working pressure, in MPa; T n is the standard state temperature, 293.15K; T is the working state temperature, unit is K; Z n is the compression factor of the standard state, dimensionless; Z is the compression factor of the working state, dimensionless.

[0115] The volume flow measurement accuracy is proportional to the compression factor calculation accuracy. The volume flow measurement accuracy of the differential pressure flowmeter has increased by an average of 8.98%. By increasing the flowmeter measurement accuracy, the circulating absorbent flow rate in the decarbonization process of high CO2 natural gas can be accurately controlled. Under the premise of ensuring that the transmission quality requirements are met, the circulating absorbent flow rate is effectively reduced, the pump power is reduced, and the economic benefits are increased.

[0116] S4. Determine the circulation flow rate of the decarbonization solvent according to the volume flow rate obtained in S3.

[0117] Embodiment 2 also discloses a decarbonization system based on an improved PR state equation, comprising:

[0118] An equation building module is used to introduce a correction coefficient x based on the gravity parameter of the original PR state equation to obtain an improved PR state equation, and obtain the CO2 content in the CO2-containing natural gas according to the chromatographic analysis instrument, and obtain the comparative temperature and comparative pressure according to the working state temperature and the working state pressure, and obtain the correction coefficient x according to the CO2 content, comparative temperature and comparative pressure, and finally obtain the improved PR state equation;

[0119] The measurement module is used to measure the working temperature and working pressure of the CO2-containing natural gas when it enters the decarbonization equipment;

[0120] A volume flow calculation module, used to calculate the volume flow of natural gas under CO2-containing conditions based on the improved PR state equation according to the working state temperature and working state pressure measured by the measurement module;

[0121] The decarbonization solvent circulation flow calculation module determines the decarbonization solvent circulation flow according to the volume flow obtained by the volume flow calculation module.

[0122] Example 3 also discloses an electronic device, comprising at least one processor, and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute a decarbonization method based on an improved PR state equation as described above.

[0123] Embodiment 4 further discloses a storage medium storing a computer program, wherein when the computer program is executed by a processor, the decarbonization method based on the improved PR state equation is implemented.

[0124] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A decarburization method based on an improved PR state equation, characterized in that: include: S1. Based on the gravity parameter of the original PR state equation, a correction coefficient x is introduced to obtain an improved PR state equation, and the CO2 content in the CO2-containing natural gas is obtained according to the chromatographic analysis instrument. At the same time, the comparative temperature and comparative pressure are obtained according to the working state temperature and the working state pressure, and the correction coefficient x is obtained according to the CO2 content, the comparative temperature and the comparative pressure, and finally the improved PR state equation is obtained; S2. Measure the working temperature and working pressure of the CO2-containing natural gas when it enters the decarbonization equipment; S3, according to the working state temperature and working state pressure measured by S2, the natural gas volume flow rate under the CO2-containing working condition is calculated based on the improved PR state equation; S4. Determine the circulation flow rate of the decarbonization solvent according to the volume flow rate obtained in S3.

2. A decarburization method based on an improved PR state equation according to claim 1, characterized in that: In S1, the specific process of introducing the correction coefficient x based on the gravity parameter of the original PR state equation to obtain the improved PR state equation is: introducing the correction coefficient x into the gravity term a in the original PR state equation, and correlating the comparison temperature, comparison pressure and the correction coefficient x, and finally obtaining the improved PR state equation.

3. A decarburization method based on an improved PR state equation according to claim 2, characterized in that: The original PR state equation is: Z 3 -(1-B)Z 2 +(A-2B-3B 2 )Z-(AB-B 2 -B 3 )=0(1); Among them, Z is the compression factor, ω is the eccentricity factor, P c is the critical pressure of the gas, in kPa, T c is the critical temperature of the gas, in K, R is the gas constant, 8.314 kJ / (kmol·K), a is the gravitational parameter, b is the volume term, T is the working temperature of the gas, A, B, α are the first intermediate parameter, the second intermediate parameter and the third intermediate parameter respectively, and P is the working pressure of the gas, in Kpa.

4. A decarburization method based on an improved PR state equation according to claim 3, characterized in that: The specific process of obtaining the correction coefficient x by comparing CO2 content, temperature and pressure is as follows: S1.

1. Introduce a correction coefficient x into the third intermediate parameter α of the gravitational parameter a, that is: S1.

2. Compress several groups of natural gas containing CO2, measure several groups of compression factors, and use the compression factors Z k Substituting into equation (1) and taking the sum of squares, we get equation (7) and equation (8): Where M is the total number of experimental data, that is, the total number of compression factors; Z k is the compression factor value of the kth group; P k is the pressure corresponding to the kth group of compression factor values, in MPa; T k is the temperature corresponding to the kth group of compression factor values, in K; f is the accuracy function; A k , B k are the first intermediate parameter and the second intermediate parameter of the kth group respectively; ci is the critical pressure of component i, in kPa; T ci is the critical temperature of component i, in K; y i is the molar content of the gas of component i; R is the gas constant, 8.314 kJ / (kmol·K); S1.

3. All corresponding correction parameters are calculated based on multiple sets of experimental data. By comparing the correction coefficient with the contrast temperature and contrast pressure, the general expression of the correction parameter x is explored using the nonlinear data fitting method, and the general expression of the correction parameter x is simplified, and finally the following formula is obtained: Among them, U1 is the fourth intermediate parameter, T r is the comparison temperature, x is the correction factor, f ω The relative molecular weight of the gas; S1.

4. U1 is calculated based on the CO2 content, comparative temperature and comparative pressure, thereby obtaining the correction parameter x under different CO2 contents, and finally obtaining the improved PR state equation.

5. A decarburization method based on an improved PR state equation according to claim 4, characterized in that: The specific process of obtaining the fourth intermediate parameter U1 is as follows: S1.4.1, respectively, the experimental data of CO2 content of 9.84%, 28.86%, 50.99%, 70.98%, 91.77% and 100% are fitted in combination with the contrast temperature and contrast pressure and the CO2 content is introduced to obtain the following equation: Among them, U1 is the fourth intermediate parameter, p1~p4 are four intermediate sub-parameters, P r is the contrast pressure, T r is the contrast temperature, y is the molar content of CO2; S1.4.

2. Solve the four intermediate sub-parameters p1 to p4 by nonlinear fitting method, and finally calculate the fourth intermediate parameter U1 according to the comparison of temperature, pressure and CO2 content.

6. A decarburization method based on an improved PR state equation according to claim 4, characterized in that: The process of S3 is to calculate the compression factor Z of the working state of natural gas containing CO2 based on the improved PR state equation, and finally apply the compression factor Z to the differential pressure flowmeter to calculate the volume flow under the working condition containing CO2: Among them, Q v is the volume flow rate in working state, in m 3 / h;Q n is the volume flow rate under standard conditions, in m 3 / h; P n is the standard pressure, 1.013MPa; P is the working pressure, in MPa; T n is the standard state temperature, 293.15K; T is the working state temperature, unit is K; Z n is the compression factor of the standard state, dimensionless; Z is the compression factor of the working state, dimensionless.

7. A decarburization method based on an improved PR state equation according to claim 1, characterized in that: The formulas for the comparative pressure and comparative temperature are: Among them, P r is the relative pressure of the gas, dimensionless; T r is the relative temperature of the gas, dimensionless; P is the working pressure of the gas, in MPa; P c is the critical pressure; T is the working temperature of the gas, in K; T c is the critical temperature.

8. A decarburization system based on an improved PR state equation, characterized in that: include: An equation building module is used to introduce a correction coefficient x based on the gravity parameter of the original PR state equation to obtain an improved PR state equation, and obtain the CO2 content in the CO2-containing natural gas according to the chromatographic analysis instrument, and obtain the comparative temperature and comparative pressure according to the working state temperature and the working state pressure, and obtain the correction coefficient x according to the CO2 content, comparative temperature and comparative pressure, and finally obtain the improved PR state equation; The measurement module is used to measure the working temperature and working pressure of the CO2-containing natural gas when it enters the decarbonization equipment; A volume flow calculation module, used to calculate the volume flow of natural gas under CO2-containing conditions based on the improved PR state equation according to the working state temperature and working state pressure measured by the measurement module; The decarbonization solvent circulation flow calculation module determines the decarbonization solvent circulation flow according to the volume flow obtained by the volume flow calculation module.

9. An electronic device, characterized in that: It includes at least one processor and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute a decarbonization method based on an improved PR state equation as described in any one of claims 1 to 7.

10. A storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the decarbonization method based on the improved PR state equation according to any one of claims 1 to 7 is implemented.

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