Calculation method of instantaneous air flow rate of compressor of one-to-one single-shaft gas turbine generator set

Abstract

The present invention discloses a method for calculating the instantaneous air flow of a compressor in a one-to-one single-shaft gas turbine generator set, which is mainly designed to solve the problem that it is difficult in the prior art to accurately obtain the instantaneous air intake flow of the compressor equipment in the one-to-one single-shaft gas turbine generator set under all operating conditions, such as steady-state conditions and variable operating conditions. The compressor air flow calculation method of the present invention includes: determination and collection of relevant parameters, calculation of actual compressor air flow under steady-state conditions, calculation of compressor design characteristic curve equation correction, calculation of compressor instantaneous flow, etc. The present invention can accurately calculate the air flow of the compressor under steady-state conditions without knowing the output power of the gas turbine, and further calculate the actual instantaneous air flow when operating under variable operating conditions, thereby providing a basis for monitoring the flow state and performance of the compressor under all operating conditions.

Description

Technical Field

[0001] The invention relates to a method for calculating the instantaneous air flow of a compressor of a one-to-one single-shaft gas turbine generator set. Background Art

[0002] Gas turbine generator sets have been rapidly developed in my country in recent years due to their high efficiency, cleanliness, flexibility, small footprint, and short construction period. A one-to-one single-shaft gas turbine generator set consists of a gas turbine, a steam turbine, a waste heat boiler, and a generator, that is, the gas turbine and the steam turbine jointly drive a generator. As an important component of the gas turbine, the main power equipment in the generator set, the operating status and performance of the gas turbine compressor directly affect the safe, reliable, and economical operation of the entire unit.

[0003] The air flow rate of the gas turbine compressor equipment is one of the key indicators to characterize the working state and performance of the compressor. It can generally be calculated by measuring parameters such as the gas turbine inlet natural gas composition, gas turbine output power, gas turbine exhaust temperature, etc., based on methods such as the gas turbine energy balance; or it can be obtained by finding the operating condition point through the compressor design operating characteristic curve provided by the equipment manufacturer.

[0004] However, firstly, when a one-to-one single-axis gas turbine generator set is in operation, only the active power of the entire generator set can be directly measured through equipment such as electric meters, and the individual power generation power of the gas turbine equipment cannot be measured, and the air flow rate of the compressor during steady-state operation cannot be calculated through common methods; secondly, some researchers have obtained the compressor air flow rate in the indirect calculation process through the waste heat boiler heat balance or steam turbine heat balance method, which is only applicable to the steady-state operation conditions of the unit, and is not applicable to variable operation conditions such as variable load of the unit; thirdly, with the increase of the operating time of the gas turbine power generation equipment, the performance of the compressor components deteriorates, and the original design characteristic curve shifts. The method of obtaining the real-time flow rate of the compressor through the compressor design characteristic curve equation is often of poor accuracy, resulting in the inability to obtain accurate air flow data through the design characteristic curve equation. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide a method for calculating the instantaneous air flow of the compressor of a one-to-one single-shaft gas turbine generator set, which obtains accurate instantaneous compressor air flow under all operating conditions by collecting and calculating a small number of parameters.

[0006] The technical solution adopted by the present invention to solve the above-mentioned problem is: a method for calculating the instantaneous air flow of the compressor of a one-to-one single-shaft gas turbine generator set, which is characterized in that by monitoring and collecting parameters such as the atmospheric pressure at the inlet of the gas turbine compressor, atmospheric temperature, atmospheric humidity, natural gas composition, natural gas flow and the oxygen content of the flue gas in the exhaust diffusion section of the gas turbine, the theoretical combustion air volume and the actual combustion excess air coefficient of the gas turbine are obtained through wet air calculation, gas turbine combustion calculation, and gas turbine material balance iterative calculation, and the actual air flow of the compressor under different steady-state conditions is obtained by multiplying the theoretical combustion air volume by the actual combustion excess air coefficient; by monitoring the compressor inlet pressure and temperature, compressor outlet pressure and temperature, and engine speed under the real-time operating state of the gas turbine, the compressor design characteristic curve equation is corrected in combination with the actual air flow data calculated at the steady-state operating point to obtain the compressor characteristic curve equation under the actual operating state; according to the actual state characteristic curve equation, the linear interpolation method is used to obtain the instantaneous compressor flow of the unit under all operating conditions such as steady-state operating conditions and variable operating conditions.

[0007] Preferably, the instantaneous air flow of the gas turbine compressor is calculated according to formula (1):

[0008]

[0009] Where: q m is the instantaneous compressor air flow; q m1 is the actual pressure ratio, and the equivalent speed ratio is The actual characteristic curve equation corresponding to the air flow calculation value, kg / s; q m2 is the actual pressure ratio, and the equivalent speed ratio is The actual characteristic curve equation corresponding to the calculated value of air flow, kg / s; is the reduced speed ratio corresponding to the actual speed; is greater than And distance The nearest reduced speed ratio; is the actual characteristic curve equation group less than And distance The nearest reduced speed ratio.

[0010] Further preferably, the equivalent speed ratio is The actual characteristic curve equation corresponding to the air flow rate q mi Calculate according to formula (2):

[0011]

[0012] Where: q mi is q in formula (1) m1 ,q m2 , kg / s; πc is the real-time pressure ratio of the compressor; is the a i , b i for Corresponding actual characteristic curve correction coefficient.

[0013] Further preferably, the actual characteristic curve correction coefficient a i , b i Calculate according to formula (3)-formula (5):

[0014]

[0015]

[0016]

[0017] Where: is the compressor pressure ratio π ci , relative reduced speed ratio The corresponding compressor design efficiency; The equivalent speed ratio is The compressor air flow corresponding to the steady-state operating point i at time t is kg / s; is the compressor pressure ratio corresponding to the steady-state operating point i; is the compressor design inlet pressure, kPa; is the compressor design inlet temperature, K; q0 is the compressor design air flow, kg / s; is the compressor inlet pressure corresponding to the steady-state operating point i, kPa; is the compressor inlet temperature corresponding to the steady-state operating point i, K; is the compressor outlet temperature corresponding to the steady-state operating point i, K; is the compressor pressure ratio corresponding to the steady-state operating point i.

[0018] Further preferably, the actual air flow rate at the steady-state operating point i of the gas turbine compressor is Calculate according to formula (6):

[0019]

[0020] Where: α is the combustion excess air coefficient; M' k is the theoretical combustion air flow rate of the gas turbine, kg / s.

[0021] Further preferably, the gas turbine theoretical combustion air quantity M′ k Calculate according to formula (7):

[0022]

[0023] Where: is the change in oxygen flow rate of gas turbine combustion, mol / h; is the mole fraction of O2 in ambient dry air, %; MW gk is the relative molecular mass of dry air, g / mol.

[0024] Further preferably, in formula (7): the change in the oxygen flow rate of the gas turbine combustion is Calculate according to formula (8):

[0025]

[0026] Where: M r is the natural gas fuel mass flow rate, kg / s; MW r is the relative molecular mass of natural gas fuel, g / mol; is the variable of oxygen per mole of component i in natural gas fuel, mol(O2) / mol(component i).

[0027] Further preferably, wet air composition calculation, gas turbine combustion calculation, and gas turbine material balance calculation are performed, and the excess air coefficient α in formula (6) is calculated iteratively. The iterative calculation steps are as follows:

[0028] ① Assume that the excess air coefficient α is a specific value α1;

[0029] ② Calculate the composition of wet air and find the molar fraction and molar flow rate of each component in the actual wet air flow rate according to formula (9) to formula (19):

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] Where: is the mole fraction of dry air in actual wet air, %; P sk is the atmospheric pressure, kPa; is the relative humidity of the atmosphere, %; is the partial pressure of saturated water vapor in moist air at the current atmospheric pressure and atmospheric temperature, kPa; is the mole fraction of water vapor in actual humid air, %; is the mole fraction of N2 in wet air, %; is the mole fraction of N2 in ambient dry air, %; is the mole fraction of O2 in wet air, %; is the mole fraction of O2 in ambient dry air, %; is the mole fraction of CO2 in moist air, %; is the mole fraction of CO2 in ambient dry air, %; is the mole fraction of Ar in wet air, %; is the mole fraction of Ar in ambient dry air, %; is the water vapor flow rate in the compressor air flow, mol / h; MW sk is the relative molecular mass of wet air, g / mol; is the N2 flow rate in the compressor air flow, mol / h; is the O2 flow rate in the compressor air flow, mol / h; is the CO2 flow rate in the compressor air flow, mol / h; is the Ar flow rate in the compressor air flow, mol / h.

[0042] ③ Carry out gas turbine combustion calculation to find the flow change of each component in the gas turbine combustion process, and calculate according to equation (8) and equation (20)-equation (24):

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] Where: is the change in H20 flow rate during combustion of gas turbine, mol / h; is the variable of H20 per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in N2 flow rate during gas turbine combustion, mol / h; is the variable of N2 per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in CO2 flow rate during gas turbine combustion, mol / h; is the CO2 variable per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in Ar flow rate during gas turbine combustion, mol / h; is the Ar variable per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in SO2 flow rate during gas turbine combustion, mol / h; The variable is SO2 per mole of component i in natural gas fuel, mol(O2) / mol(component i).

[0049] ④ Carry out gas turbine material balance calculation to find the molar flow rate of each component in the gas turbine flue gas composition according to equations (25) to (30):

[0050]

[0051]

[0052]

[0053]

[0054]

[0055]

[0056] In the formula, is the molar flow rate of H2O in the flue gas, mol / h; is the molar flow rate of N2 in the flue gas, mol / h; is the molar flow rate of O2 in flue gas, mol / h; is the molar flow rate of CO2 in flue gas, mol / h; is the molar flow rate of Ar in the flue gas, mol / h; is the molar flow rate of SO2 in flue gas, mol / h.

[0057] ⑤ Calculate the O2 mole fraction in the dry flue gas of the gas turbine according to formula (31):

[0058]

[0059] Where: is the mole fraction of oxygen in dry flue gas, %.

[0060] ⑥ Iteration condition determination:

[0061] like Then: α2=α1+Δα, repeat steps ②-⑤;

[0062] like Then: α=α i ;

[0063] Where: An online flue gas analyzer is installed at the exhaust diffusion section of the gas turbine to actually measure the flue gas O2 mole fraction, %.

[0064] Compared with the prior art, the present invention has the following advantages and effects: the present invention can obtain the instantaneous actual air flow of the compressor of a one-to-one single-shaft gas turbine generator set by monitoring and collecting a small amount of parameters, including the air flow under all operating conditions such as steady-state operation and variable operating conditions of the compressor, and is not limited by the operating conditions of the compressor; at the same time, the present invention is not limited by the gas turbine manufacturer and model, has a wide range of applications, and is not limited by the performance degradation of the equipment during the operation process. The calculation result has high accuracy, fundamentally solving the problem that the compressor air flow cannot be accurately obtained during the operation of the one-to-one single-shaft gas turbine generator set, and has great practical value in single-shaft gas turbine generator sets. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a flow chart of the instantaneous air flow calculation method of the compressor of a one-to-one single-shaft gas turbine generator set in the present invention. DETAILED DESCRIPTION

[0066] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0067] Example

[0068] See also Figure 1 In this embodiment, a method for calculating the instantaneous air flow of the compressor of a one-to-one single-shaft gas turbine generator set includes parameter monitoring and collection, calculation of the actual compressor air flow under steady-state conditions, calculation of the compressor design characteristic curve equation correction, and calculation of the compressor instantaneous flow. The monitoring and collection parameters include atmospheric pressure, atmospheric temperature, atmospheric humidity, natural gas composition, natural gas flow, oxygen content of flue gas in the exhaust diffusion section of the gas turbine, gas turbine speed, compressor inlet pressure and temperature, compressor outlet pressure and temperature, etc. The calculation method of this embodiment is specifically described below:

[0069] 1. Calculation of actual compressor air flow under steady-state operating conditions, including wet air calculation, theoretical combustion air volume calculation, excess air coefficient iterative calculation, compressor air flow calculation, etc.

[0070] 1.1. Calculation of wet air.

[0071] The atmospheric pressure, atmospheric temperature and atmospheric humidity at the inlet of the gas turbine compressor are monitored and collected. The mole fractions of N2, O2, CO2 and Ar in standard dry air are known data. According to the atmospheric pressure and atmospheric temperature, the saturated vapor pressure in wet air at the current atmospheric pressure and atmospheric temperature can be obtained by looking up the table. The mole fraction calculation formula of each component in wet air is:

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078] is the mole fraction of dry air in actual wet air, %; P sk is the atmospheric pressure, kPa; is the relative humidity of the atmosphere, %; is the partial pressure of saturated water vapor in moist air at the current atmospheric pressure and atmospheric temperature, kPa; is the mole fraction of water vapor in actual humid air, %; is the mole fraction of N2 in wet air, %; is the mole fraction of N2 in ambient dry air, %; is the mole fraction of O2 in wet air, %; is the mole fraction of O2 in ambient dry air, %; is the mole fraction of CO2 in moist air, %; is the mole fraction of CO2 in ambient dry air, %; is the mole fraction of Ar in wet air, %; is the mole fraction of Ar in ambient dry air, %;

[0079] The relative molecular masses of H2O, N2, O2, CO2, and Ar in humid air are known data, so the calculation formula for the average relative molecular mass of humid air is:

[0080]

[0081] Where: MW sk is the average relative molecular mass of wet air, g / mol; MW H is the average relative molecular mass of H2O, g / mol; MW N is the average relative molecular mass of N2, g / mol; MW O is the average relative molecular mass of O2, g / mol; MW C is the average relative molecular mass of CO2, g / mol; MW A is the average relative molecular mass of Ar, g / mol.

[0082] 1.2. Calculation of theoretical combustion air volume.

[0083] Monitor and collect the molar fraction of each component of natural gas fuel for gas turbines and the natural gas mass flow rate. The relative molecular mass of each component of natural gas is known data, so the calculation formula for the average relative molecular mass of natural gas is:

[0084]

[0085] Where: MW r is the average molecular weight of natural gas, g / mol; MF i is the mole fraction of natural gas component i, %; MW i is the relative molecular mass of each component, g / mol.

[0086] The calculation formula for the change in theoretical combustion oxygen flow rate of the gas turbine is:

[0087]

[0088] Where: is the change in oxygen flow rate of gas turbine combustion theory, mol / h; M r is the natural gas fuel mass flow rate, kg / s; It is the variable of oxygen corresponding to each mole of component i in natural gas fuel, mol(O2) / mol(i component).

[0089] The relative molecular mass of standard dry air is a known data, so the calculation formula for the theoretical combustion air volume of the gas turbine is:

[0090]

[0091] Where: M′ k is the theoretical combustion air flow rate of the gas turbine, kg / s; MW gk is the relative molecular mass of dry air, g / mol.

[0092] 1.3. Iterative calculation of excess air coefficient.

[0093] The calculation of the excess air coefficient of gas turbine combustion includes the gas turbine combustion calculation and material balance calculation. First, it is assumed that the excess air coefficient of gas turbine combustion is a specific value. The material variables before and after combustion are analyzed by combustion calculation. The material balance calculation is used as the iterative calculation judgment condition of the excess air coefficient of gas turbine combustion. Finally, the actual excess air coefficient of gas turbine combustion is obtained. The specific steps are as follows:

[0094] ① Assume that the excess air coefficient α of the gas turbine combustion is a specific value α1;

[0095] ② Carry out gas turbine combustion calculation and analyze the flow change of each component before and after gas turbine combustion. The calculation formula is:

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102] Where: is the change in H20 flow rate during combustion of gas turbine, mol / h; is the variable of H20 corresponding to each mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in N2 flow rate during gas turbine combustion, mol / h; is the variable of N2 corresponding to each mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in CO2 flow rate during gas turbine combustion, mol / h; is the CO2 variable corresponding to each mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in Ar flow rate during gas turbine combustion, mol / h; is the Ar variable corresponding to each mole of component i in natural gas fuel, mol(O2) / mol(i component); is the change in SO2 flow rate during gas turbine combustion, mol / h; It is the variable of SO2 corresponding to each mole of component i in natural gas fuel, mol(O2) / mol(i component).

[0103] ③ The calculation formula for the molar flow of each component in the actual wet air flow is:

[0104]

[0105]

[0106]

[0107]

[0108]

[0109] Where: is the water vapor flow rate in the compressor air flow rate, mol / h; is the N2 flow rate in the compressor air flow, mol / h; is the O2 flow rate in the compressor air flow, mol / h; is the CO2 flow rate in the compressor air flow, mol / h; is the Ar flow rate in the compressor air flow, mol / h.

[0110] ④ After calculating the flow change of each component before and after the gas turbine combustion and the molar flow of each component of the wet air entering the compressor, the molar flow of each component of the flue gas after the gas turbine combustion can be calculated based on the material balance calculation. The calculation formula is:

[0111]

[0112]

[0113]

[0114]

[0115]

[0116]

[0117] In the formula, is the molar flow rate of H2O in the flue gas, mol / h; is the molar flow rate of N2 in the flue gas, mol / h; is the molar flow rate of O2 in flue gas, mol / h; is the molar flow rate of CO2 in flue gas, mol / h; is the molar flow rate of Ar in the flue gas, mol / h; is the molar flow rate of SO2 in flue gas, mol / h.

[0118] The calculation formula for the O2 mole fraction in the dry flue gas after gas turbine combustion is:

[0119]

[0120] Where: is the calculated value of the mole fraction of oxygen in dry flue gas, %.

[0121] ⑥ The iterative calculation judgment conditions are analyzed as follows:

[0122] If it is assumed that the value of the excess air coefficient α1 of the gas turbine combustion is correct, then the calculated value of the O2 mole fraction in the dry flue gas based on the material balance should be equal to the O2 mole fraction measured at the gas turbine exhaust diffusion section, so:

[0123] like but:

[0124] α=α1;

[0125] like but:

[0126] α2=α1+Δα;

[0127] Repeat steps ②-⑤ until α i =α i-1 +Δα;

[0128] but:

[0129] α=α i :

[0130] Where: An online flue gas analyzer is installed at the exhaust diffusion section of the gas turbine to actually measure the O2 mole fraction in the dry flue gas, %.

[0131] 1.4. Calculation of actual air flow of the compressor under steady-state conditions.

[0132] After calculating the gas turbine theoretical combustion air flow and the combustion excess air coefficient, the compressor air flow can be obtained by multiplying the two. The calculation formula is:

[0133]

[0134] Where: is the compressor air flow rate corresponding to the gas turbine steady-state operating point i, kg / s.

[0135] 2. Correction calculation of compressor design characteristic curve equation.

[0136] The equation of the compressor equipment operation design characteristic curve is:

[0137]

[0138]

[0139] Where: q m is the compressor air flow, kg / s; π c is the compressor pressure ratio; is the reduced speed ratio; η is the compressor efficiency, %;

[0140] During the operation of the compressor, the design characteristic curve of the compressor equipment shifts due to performance degradation and other reasons. It is assumed that the characteristic curve equation after the shift is:

[0141]

[0142] Where: q mi is the corrected compressor characteristic curve equation, kg / s; a i , b i for Corresponding characteristic curve correction factor.

[0143] According to the different steady-state operating data of the gas turbine, the actual air flow of the compressor corresponding to the steady-state operating point i is obtained by steady-state operating calculation. The objective function formula for solving the correction coefficient is:

[0144]

[0145] Where: The equivalent speed ratio is The compressor air flow corresponding to the steady-state operating point i at time t is kg / s; is the compressor pressure ratio corresponding to the steady-state operating point i; is the compressor design inlet pressure, kPa; is the compressor design inlet temperature, K; q0 is the compressor design air flow, kg / s; is the compressor inlet pressure corresponding to the steady-state operating point i, kPa; is the compressor inlet temperature corresponding to the steady-state operating point i, K; is the compressor outlet temperature corresponding to the steady-state operating point i, K; is the compressor pressure ratio corresponding to the steady-state operating point i.

[0146] Reduced speed ratio The calculation formula is:

[0147]

[0148] Where: n i is the actual speed of the gas turbine, rmin; n0 is the design speed of the gas turbine, rmin.

[0149] Compressor pressure ratio The calculation formula is:

[0150]

[0151] Where: is the compressor outlet pressure corresponding to the steady-state operating point i, kPa.

[0152] The objective function of the correction coefficient can be further calculated to obtain the correction coefficient calculation formula:

[0153]

[0154] The correction coefficient a is obtained from the above formula i , b i The specific value is obtained to obtain the corrected actual compressor characteristic curve equation.

[0155] 3. Calculation of actual instantaneous air flow of the compressor.

[0156] According to the actual state characteristic curve equation, the linear interpolation method is used to obtain the real-time compressor flow rate of the unit under all working conditions such as steady-state working conditions and variable working conditions. The calculation formula is:

[0157]

[0158] Where: q m is the real-time compressor air flow; q m1 is the actual pressure ratio, and the equivalent speed ratio is The actual characteristic curve equation corresponding to the air flow calculation value, kg / s; q m2 is the actual pressure ratio, and the equivalent speed ratio is The actual characteristic curve equation corresponding to the calculated value of air flow, kg / s; is the reduced speed ratio corresponding to the actual speed; To obtain the actual characteristic curve equation group greater than And distance The nearest reduced speed ratio; To obtain the actual characteristic curve equations less than And distance The nearest reduced speed ratio.

[0159] In summary, the calculation of instantaneous air flow of the compressor of the one-to-one single-shaft gas turbine generator set is completed.

[0160] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

[0161] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the protection scope of the present invention. Any changes and modifications made by any technician familiar with the technology without departing from the concept and scope of the present invention should fall within the protection scope of the present invention.

Claims

1. A method for calculating the instantaneous air flow of a compressor of a one-to-one single-shaft gas turbine generator set, characterized in that: By monitoring and collecting the atmospheric pressure, atmospheric temperature, atmospheric humidity, natural gas composition, natural gas flow rate and oxygen content parameters of flue gas in the exhaust diffusion section of the gas turbine compressor, the theoretical combustion air volume and the actual combustion excess air coefficient of the gas turbine are obtained through wet air calculation, gas turbine combustion calculation and gas turbine material balance iterative calculation, and the actual air flow rate of the compressor under different steady-state conditions is obtained by multiplying the theoretical combustion air volume by the actual combustion excess air coefficient; by monitoring the compressor inlet pressure and temperature, compressor outlet pressure and temperature, and gas turbine speed under the real-time operating state of the gas turbine, the compressor design characteristic curve equation is corrected in combination with the actual air flow data calculated at the steady-state operating point, and the compressor characteristic curve equation under the actual operating state is obtained; According to the actual state characteristic curve equation, the instantaneous flow rate of the compressor in all working conditions of the unit is obtained by linear interpolation method; The instantaneous air flow rate of the gas turbine compressor is calculated according to formula (1): Where: q m is the instantaneous compressor air flow; q m1 is the actual pressure ratio, and the equivalent speed ratio is The actual characteristic curve equation corresponding to the air flow calculation value, kg / s; q m2 is the actual pressure ratio, and the equivalent speed ratio is The actual characteristic curve equation corresponding to the calculated value of air flow, kg / s; is the reduced speed ratio corresponding to the actual speed; is greater than And distance The nearest reduced speed ratio; is the actual characteristic curve equation group less than And distance The nearest reduced speed ratio; The equivalent speed ratio is The actual characteristic curve equation corresponding to the air flow rate q mi Calculate according to formula (2): Where: q mi is q in formula (1) m1 ,q m2 , kg / s; π c is the real-time pressure ratio of the compressor; is the a i , b i for The corresponding actual characteristic curve correction coefficient; Actual characteristic curve correction coefficient a i , b i Calculate according to formula (3)-formula (5): Where: is the compressor pressure ratio π ci , relative reduced speed ratio The corresponding compressor design efficiency; The equivalent speed ratio is The compressor air flow corresponding to the steady-state operating point i at time t is kg / s; is the compressor pressure ratio corresponding to the steady-state operating point i; is the compressor design inlet pressure, kPa; is the compressor design inlet temperature, K; q0 is the compressor design air flow, kg / s; is the compressor inlet pressure corresponding to the steady-state operating point i, kPa; is the compressor inlet temperature corresponding to the steady-state operating point i, K; is the compressor outlet temperature corresponding to the steady-state operating point i, K; is the compressor pressure ratio corresponding to the steady-state operating point i; Actual air flow rate at steady-state operating point i of gas turbine compressor Calculate according to formula (6): Where: α is the combustion excess air coefficient; M' k is the theoretical combustion air flow rate of the gas turbine, kg / s; Theoretical combustion air volume of gas turbine M' k Calculate according to formula (7): Where: is the change in oxygen flow rate of gas turbine combustion, mol / h; is the mole fraction of O2 in ambient dry air, %; MW gk is the relative molecular mass of dry air, g / mol; In formula (7): The change in oxygen flow rate during combustion of gas turbine is Calculate according to formula (8): Where: M r is the natural gas fuel mass flow rate, kg / s; MW r is the relative molecular mass of natural gas fuel, g / mol; is the variable of oxygen per mole of component i in natural gas fuel, mol(O2) / mol(component i); The wet air composition calculation, gas turbine combustion calculation, and gas turbine material balance calculation are performed, and the excess air coefficient α in formula (6) is calculated iteratively. The iterative calculation steps are as follows: ① Assume that the excess air coefficient α is a specific value α1; ② Calculate the composition of wet air and find the molar fraction and molar flow rate of each component in the actual wet air flow rate according to formula (9) to formula (19): Where: is the mole fraction of dry air in actual wet air, %; P sk is the atmospheric pressure, kPa; is the relative humidity of the atmosphere, %; is the partial pressure of saturated water vapor in moist air at the current atmospheric pressure and atmospheric temperature, kPa; is the mole fraction of water vapor in actual humid air, %; is the mole fraction of N2 in wet air, %; is the mole fraction of N2 in ambient dry air, %; is the mole fraction of O2 in wet air, %; is the mole fraction of O2 in ambient dry air, %; is the mole fraction of CO2 in moist air, %; is the mole fraction of CO2 in ambient dry air, %; is the mole fraction of Ar in wet air, %; is the mole fraction of Ar in ambient dry air, %; is the water vapor flow rate in the compressor air flow, mol / h; MW sk is the relative molecular mass of wet air, g / mol; is the N2 flow rate in the compressor air flow, mol / h; is the O2 flow rate in the compressor air flow, mol / h; is the CO2 flow rate in the compressor air flow, mol / h; is the Ar flow rate in the compressor air flow, mol / h; ③ Carry out gas turbine combustion calculation to find the flow rate change of each component in the gas turbine combustion process, and calculate according to equation (8) and equation (20)-equation (24): Where: is the change in H2O flow rate during gas turbine combustion, mol / h; is the variable of H2O per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in N2 flow rate during gas turbine combustion, mol / h; is the variable of N2 per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in CO2 flow rate during gas turbine combustion, mol / h; is the CO2 variable per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in Ar flow rate during gas turbine combustion, mol / h; is the Ar variable per mole of component i in natural gas fuel, mol(O2) / mol(component i); is the change in SO2 flow rate during gas turbine combustion, mol / h; is the variable of SO2 per mole of component i in natural gas fuel, mol(O2) / mol(component i); ④ Carry out gas turbine material balance calculation to find the molar flow rate of each component in the gas turbine flue gas composition according to equations (25) to (30): In the formula, is the molar flow rate of H2O in the flue gas, mol / h; is the molar flow rate of N2 in the flue gas, mol / h; is the molar flow rate of O2 in flue gas, mol / h; is the molar flow rate of CO2 in flue gas, mol / h; is the molar flow rate of Ar in the flue gas, mol / h; is the molar flow rate of SO2 in flue gas, mol / h; ⑤ Calculate the O2 mole fraction in the dry flue gas of the gas turbine according to formula (31): Where: is the mole fraction of oxygen in dry flue gas, %; ⑥ Iteration condition determination: like Then: α2=α1+Δα, repeat steps ②-⑤; like Then: α=α i ; Where: An online flue gas analyzer is installed at the exhaust diffusion section of the gas turbine to actually measure the flue gas O2 mole fraction, %.

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