Method for evaluating influence of cylinder effect on whole machine based on multi-type and variable working condition operation steam turbine

Abstract

This invention relates to a method for assessing the impact of turbine cylinder efficiency on the overall turbine under multiple turbine types and varying operating conditions. Employing the equivalent enthalpy drop method and based on the small-deviation theory, it calculates the comprehensive impact of changes in the absolute values ​​of high-pressure, intermediate-pressure, and low-pressure cylinder efficiency on the entire turbine, thereby obtaining an assessment of the impact of cylinder efficiency changes on the turbine unit's heat rate and electrical power. Compared with existing technologies, this invention avoids the problem of incomplete calculations due to missing thermodynamic data, overcomes the complexity of traditional thermodynamic calculation methods, allows for understanding the unit's variable operating conditions, analyzes the work ratio and share of each turbine cylinder, and accurately and quickly calculates the impact on the overall heat rate. It provides a calculation basis for diagnosing the thermal economy of turbines and predicting the economic benefits of turbine flow path modifications.

Description

Technical Field

[0001] This invention relates to the field of large-scale thermal power generation steam turbine technology, and in particular to a method for assessing the impact of turbine cylinder efficiency on the whole unit based on multiple turbine models and variable operating conditions. Background Technology

[0002] During long-term operation, steam turbine units experience significant deviations between actual and designed heat consumption due to wear and scaling. Cylinder efficiency is the most crucial indicator of turbine performance, directly reflecting its quality. Utilizing cylinder efficiency variations to determine their impact on heat consumption not only allows for understanding the unit's variable operating conditions and analyzing the power contribution ratio and share of each cylinder, but also enables prediction of the thermal economics of modifying the turbine's flow path. Accurately and quickly calculating the impact of cylinder efficiency on heat consumption rate is a hot topic of common concern among thermal system engineers.

[0003] Currently, the main methods for calculating the change in heat rate caused by changes in cylinder efficiency include the thermodynamic performance analysis software method, the assumed variable method, and the available energy calculation method. When performing calculations for different operating conditions and thermodynamic systems, thermodynamic performance analysis software requires building different models. Many parameter settings simplify the calculation conditions, and it is difficult to meet calculation requirements when certain thermodynamic data are missing. The assumed variable method can only calculate certain special cases; in actual operation, many factors affect the heat rate, making it lack universality. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a method for assessing the impact of turbine cylinder efficiency on the entire turbine under multiple models and variable operating conditions, thus meeting the needs for simple, efficient, and accurate thermodynamic performance analysis. This method allows for timely understanding of the unit's variable operating conditions, analysis of the work ratio and share of each turbine cylinder, and provides technical support for determining whether to utilize downtime opportunities to perform necessary flow passage maintenance on each turbine cylinder.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A method for assessing the impact of turbine cylinder efficiency on the whole unit under multiple turbine types and variable operating conditions is proposed. The method adopts the equivalent enthalpy drop method and is based on the small deviation theory. It calculates the comprehensive impact of the absolute value changes of high-pressure cylinder efficiency, intermediate-pressure cylinder efficiency, and low-pressure cylinder efficiency on the whole unit, thereby obtaining the assessment results of the impact of cylinder efficiency changes on the heat rate and electric power of the turbine unit.

[0007] The calculation process for the comprehensive impact of the absolute value change in the high-pressure cylinder efficiency on the whole machine includes the following steps:

[0008] S11. Obtain the main steam pressure and main steam temperature, and calculate the main steam enthalpy and main steam entropy;

[0009] S12. Obtain the exhaust pressure and temperature of the high-pressure cylinder, calculate the exhaust enthalpy and ideal exhaust enthalpy of the high-pressure cylinder by combining the main steam entropy, further calculate the utilization energy and available energy of the high-pressure cylinder, and finally obtain the design value of the high-pressure cylinder efficiency.

[0010] S13. Based on the preset high-pressure cylinder efficiency, calculate the impact of the change in high-pressure cylinder efficiency on the heat consumption rate and the heat absorption of the reheater, and then calculate the comprehensive impact of the change in the absolute value of the high-pressure cylinder efficiency on the whole machine.

[0011] S14. Finally, calculate the impact of the change in high-pressure cylinder efficiency on heat consumption.

[0012] Furthermore, in step S11, the main steam enthalpy H ms and the entropy of the main steam S ms The calculation formula is as follows:

[0013] H ms =StmPTH(P ms ,T ms ,1)

[0014] S ms =StmPTS(P ms ,T ms ,1)

[0015] Among them, P ms T represents the main steam pressure. ms This represents the main steam temperature; StmPTH represents the enthalpy calculation function; and StmPTS represents the entropy calculation function.

[0016] In step S12, the high-pressure cylinder efficiency design value η hp The calculation formula is as follows:

[0017] η hp =ΔH hpt / ΔH hpi

[0018] ΔH hpt =H ms -H crht

[0019] ΔH hpi =H ms -H crhi

[0020] H crht =StmPTH(P crh ,T crh ,1)

[0021] H crhi =StmPSH(Pcrh ,S ms ,1)

[0022] Where, ΔH hpt ΔH represents the energy utilized by the high-pressure cylinder. hpi H represents the available energy of the high-pressure cylinder. crht H represents the enthalpy of high-pressure cylinder exhaust. crhi P represents the ideal exhaust enthalpy of the high-pressure cylinder. crh T represents the exhaust pressure of the high-pressure cylinder. crh This represents the exhaust temperature of the high-pressure cylinder, and StmPSH represents the function for calculating the ideal exhaust enthalpy.

[0023] Furthermore, the overall impact η of the absolute value change ε1% of the high-pressure cylinder efficiency in step S13 on the entire machine. hczj The calculation formula is as follows:

[0024] η hczj =Δη hcr -Δη hcz

[0025] Δη hcr =Δη hp *ΔH hpt *F ms / (3600*N t )

[0026] Δη hcz =Δη hp *ΔH hpt *F hrh / (HR*N t )

[0027] Δη hp =(η hp -η hpt ) / η hp *100

[0028] η hpt =η hp -ε1

[0029] Where, Δη hcr This represents the direct impact of high-pressure cylinder efficiency on heat consumption, Δη. hcz The effect of high-pressure cylinder efficiency on reheater heat absorption is expressed as Δη. hp F represents the relative change in the efficiency of the high-pressure cylinder. ms N represents the main steam flow rate. t Indicates generator output, η hp η represents the design value of the high-pressure cylinder efficiency. hpt F represents the assumed value of the high-pressure cylinder efficiency, ε1 represents the change in the high-pressure cylinder efficiency, and F hrh Indicates the reheat steam flow rate;

[0030] In step S14, the effect of the high-pressure cylinder efficiency change on heat consumption ΔHR HP The calculation formula is as follows:

[0031] ΔHR HP =ζ HP *HR / 100

[0032] ζ HP =Δη hczj / Δη hp

[0033] Where, ζ HP This indicates the proportion of the impact of the high-pressure cylinder efficiency change on the whole machine, and HR represents the turbine heat rate.

[0034] The calculation process for the comprehensive impact of the change in the absolute value of the intermediate pressure cylinder efficiency on the whole machine includes the following steps:

[0035] S21. Obtain the hot revapor pressure and hot revapor temperature, and calculate the hot revapor enthalpy and hot revapor entropy.

[0036] S22. Obtain the intermediate pressure cylinder exhaust pressure and intermediate pressure cylinder exhaust temperature, and calculate the intermediate pressure cylinder exhaust enthalpy and the ideal intermediate pressure cylinder exhaust enthalpy by combining the heat reheat steam entropy. Further calculate the utilization energy and available energy of the intermediate pressure cylinder, and finally calculate the intermediate pressure cylinder efficiency design value.

[0037] S23. Based on the preset intermediate-pressure cylinder efficiency, calculate the effect of the intermediate-pressure cylinder efficiency change on the heat consumption rate (the exhaust steam from the high-pressure cylinder absorbs heat through the reheater and then enters the intermediate-pressure cylinder, so the effect of the intermediate-pressure cylinder efficiency on the heat absorption of the reheater is 0), and then calculate the comprehensive effect of the change in the absolute value of the intermediate-pressure cylinder efficiency on the whole machine.

[0038] S24. Finally, calculate the impact of the change in intermediate pressure cylinder efficiency on heat consumption.

[0039] Furthermore, in step S21, the enthalpy of reheat vapor H hr and reheat steam entropy S hr The calculation formula is as follows:

[0040] H hr =StmPTH(P hr ,T hr ,1)

[0041] S hr =StmPTS(P hr ,T hr ,1)

[0042] Among them, P hr T represents the hot resteam pressure. hr Indicates the temperature of the hot resteam;

[0043] In step S22, the design value η of the intermediate pressure cylinder efficiency hr The calculation formula is as follows:

[0044] η hr =ΔH hr / ΔH hri

[0045] ΔH hr =H hr -H hrh

[0046] ΔH hri =H hr -H hrhi

[0047] H hrh =StmPTH(P hrc ,T hr ,1)

[0048] H hrhi =StmPSH(P hrc ,S hr ,1)

[0049] Where, ΔH hr ΔH represents the energy utilized by the intermediate pressure cylinder. hri H represents the available energy of the intermediate pressure cylinder. hrh H represents the enthalpy of exhaust gas from the intermediate-pressure cylinder. hrhi P represents the ideal exhaust enthalpy of the intermediate-pressure cylinder. hr T represents the exhaust pressure of the intermediate pressure cylinder. hr This indicates the exhaust temperature of the intermediate pressure cylinder.

[0050] Furthermore, the overall impact η of the absolute change ε2% in the efficiency of the intermediate-pressure cylinder in step S23 on the entire machine. hrzj The calculation formula is as follows:

[0051] η hrzj =Δη hrr

[0052] Δη hrr =Δη hr *ΔH hr *F hrh / (3600*N t )

[0053] Δη hr =(η hr -η hrt ) / η hr *100

[0054] η hrt =ηhr -ε2

[0055] Where, Δη hrr The direct impact of intermediate-pressure cylinder efficiency on heat consumption is represented by Δη. hr F represents the relative change in the efficiency of the intermediate-pressure cylinder. hrh N represents the reheat steam flow rate. t Indicates generator output, η hr η represents the design value of the intermediate pressure cylinder efficiency. hrt ε1 represents the assumed value of the intermediate pressure cylinder efficiency, and ε2 represents the change in the intermediate pressure cylinder efficiency.

[0056] The effect of the change in intermediate pressure cylinder efficiency on heat consumption ΔHR in step S24 IP The calculation formula is as follows:

[0057] ΔHR IP =ζ IP *HR / 100

[0058] ζ IP =Δη hrzj / Δη hr

[0059] Where, ζ IP This indicates the proportion of the impact of changes in intermediate-pressure cylinder efficiency on the overall machine, and HR represents the turbine heat rate.

[0060] The calculation process for the comprehensive impact of the change in the absolute value of the low-pressure cylinder efficiency on the whole machine includes the following steps:

[0061] S31. Obtain the low-pressure cylinder inlet steam pressure and low-pressure cylinder inlet steam temperature, and calculate the low-pressure cylinder inlet steam enthalpy and low-pressure cylinder inlet steam entropy.

[0062] S32. The exhaust enthalpy of the low-pressure cylinder is obtained by the energy balance iterative algorithm. The ideal exhaust enthalpy of the low-pressure cylinder is obtained by solving the exhaust pressure and inlet entropy of the low-pressure cylinder. The utilization energy and available energy of the low-pressure cylinder are further calculated, and finally the design value of the efficiency of the low-pressure cylinder is calculated.

[0063] S33. Based on the preset low-pressure cylinder efficiency, calculate the effect of the change in low-pressure cylinder efficiency on the heat consumption rate (after the exhaust steam from the high-pressure cylinder absorbs heat through the reheater, it enters the intermediate-pressure cylinder, so the effect of the low-pressure cylinder efficiency on the heat absorption of the reheater is 0), and then calculate the comprehensive effect of the change in the absolute value of the low-pressure cylinder efficiency on the whole machine.

[0064] S34. Finally, calculate the impact of the change in low-pressure cylinder efficiency on heat consumption.

[0065] Furthermore, in step S31, the enthalpy H of the low-pressure cylinder inlet steam... ep and low-pressure cylinder inlet steam entropy S ep The calculation formula is as follows:

[0066] H ep =StmPTH(P ep ,T ep ,1)

[0067] S ep =StmPTS(P ep ,T ep ,1)

[0068] Among them, P ep T represents the low-pressure cylinder inlet pressure. ep Indicates the low-pressure cylinder inlet steam temperature;

[0069] In step S32, the design value of the low-pressure cylinder efficiency η hep The calculation formula is as follows:

[0070] η hep =ΔH ep / ΔH epi

[0071] ΔH ep =H ueep -H ueepi

[0072] ΔH epi =H ep -H ueepi

[0073] H ueepi =StmPSH(P ueep ,S ep ,1)

[0074] Where, ΔH ep ΔH represents the energy utilized by the low-pressure cylinder. epi H represents the available energy of the low-pressure cylinder. ueep H represents the enthalpy of low-pressure cylinder exhaust. ueepi P represents the ideal exhaust enthalpy of the low-pressure cylinder. ueep This indicates the exhaust pressure of the low-pressure cylinder.

[0075] Furthermore, the overall impact η of the absolute change ε3% in the low-pressure cylinder efficiency in step S33 on the entire machine. hepzj The calculation formula is as follows:

[0076] η hepzj =Δη hepr

[0077] Δη hepr =Δη hep *ΔH ep *F ueep / (3600*N t )

[0078] Δη hep =(η hep -η hept ) / η hep *100

[0079] η hept =η hep -ε3

[0080] Where, Δη hepr This represents the direct impact of low-pressure cylinder efficiency on heat consumption, Δη. hep F represents the relative change in low-pressure cylinder efficiency. ueep This indicates the steam flow rate entering the low-pressure cylinder, N. t Indicates generator output, η hep η represents the design value for low-pressure cylinder efficiency. hept ε3 represents the assumed value of the low-pressure cylinder efficiency, and ε3 represents the change in the low-pressure cylinder efficiency.

[0081] In step S34, the effect of the low-pressure cylinder efficiency change on heat consumption ΔHR LP The calculation formula is as follows:

[0082] ΔHR LP =ζ LP *HR / 100

[0083] ζ LP =Δη hepzj / Δη hep

[0084] Where, ζ LP This indicates the proportion of the impact of changes in low-pressure cylinder efficiency on the overall machine, and HR represents the turbine heat rate.

[0085] Compared with the prior art, the present invention has the following beneficial effects:

[0086] 1. This invention uses available energy to calculate the change in heat rate caused by changes in cylinder efficiency. This not only avoids the problem of missing thermodynamic data during the calculation of the influence of heat rate, but also overcomes the complexity of traditional thermodynamic calculation methods.

[0087] 2. This invention calculates the impact of cylinder ratio changes on heat consumption from three aspects: high-pressure cylinder, medium-pressure cylinder, and low-pressure cylinder. It can not only understand the unit's operating conditions under different operating conditions and analyze the work ratio and share of each cylinder in the turbine, but also accurately and quickly calculate the impact on the overall heat consumption rate of the unit.

[0088] 3. This invention provides a calculation basis for diagnosing the thermal economy of steam turbines and predicting the economic benefits of modifying the flow path of steam turbines. Attached Figure Description

[0089] Figure 1 This is a flowchart illustrating the algorithm for the impact of high-pressure cylinder efficiency changes on heat consumption in this invention.

[0090] Figure 2 This is a flowchart illustrating the algorithm for the impact of cylinder efficiency variation on heat consumption in this invention.

[0091] Figure 3 This is a flowchart illustrating the algorithm for the impact of low-pressure cylinder efficiency variation on heat consumption in this invention.

[0092] Figure 4 This is a correction curve of the high, medium and low pressure cylinder efficiency versus heat consumption rate in a certain manufacturing plant according to an embodiment of the present invention. Detailed Implementation

[0093] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0094] Example

[0095] A method for assessing the impact of turbine cylinder efficiency on the whole unit under multiple turbine types and variable operating conditions is proposed. The method adopts the equivalent enthalpy drop method and is based on the small deviation theory. It calculates the comprehensive impact of the absolute value changes of high-pressure cylinder efficiency, intermediate-pressure cylinder efficiency, and low-pressure cylinder efficiency on the whole unit, thereby obtaining the assessment results of the impact of cylinder efficiency changes on the heat rate and electric power of the turbine unit.

[0096] like Figure 1 As shown, the calculation process for the comprehensive impact of the absolute value change in the high-pressure cylinder efficiency on the whole machine includes the following steps:

[0097] S11. Obtain the main steam pressure and main steam temperature, and calculate the main steam enthalpy and main steam entropy;

[0098] S12. Obtain the exhaust pressure and temperature of the high-pressure cylinder, calculate the exhaust enthalpy and ideal exhaust enthalpy of the high-pressure cylinder by combining the main steam entropy, further calculate the utilization energy and available energy of the high-pressure cylinder, and finally obtain the design value of the high-pressure cylinder efficiency.

[0099] S13. Based on the preset high-pressure cylinder efficiency, calculate the impact of the change in high-pressure cylinder efficiency on the heat consumption rate and the heat absorption of the reheater, and then calculate the comprehensive impact of the change in the absolute value of the high-pressure cylinder efficiency on the whole machine.

[0100] S14. Finally, calculate the impact of the change in high-pressure cylinder efficiency on heat consumption.

[0101] In step S11, the main steam enthalpy H ms and the entropy of the main steam S ms The calculation formula is as follows:

[0102] H ms =StmPTH(P ms ,T ms ,1)

[0103] S ms =StmPTS(P ms ,T ms ,1)

[0104] Among them, P ms T represents the main steam pressure. ms This represents the main steam temperature; StmPTH represents the enthalpy calculation function; and StmPTS represents the entropy calculation function.

[0105] In step S12, the design value of the high-pressure cylinder efficiency η hp The calculation formula is as follows:

[0106] η hp =ΔH hpt / ΔH hpi

[0107] ΔH hpt =H ms -H crht

[0108] ΔH hpi =H ms -H crhi

[0109] H crht =StmPTH(P crh ,T crh ,1)

[0110] H crhi =StmPSH(P crh ,S ms ,1)

[0111] Where, ΔH hpt ΔH represents the energy utilized by the high-pressure cylinder. hpi H represents the available energy of the high-pressure cylinder. crht H represents the enthalpy of high-pressure cylinder exhaust. crhi P represents the ideal exhaust enthalpy of the high-pressure cylinder. crh T represents the exhaust pressure of the high-pressure cylinder. crh This represents the exhaust temperature of the high-pressure cylinder, and StmPSH represents the function for calculating the ideal exhaust enthalpy.

[0112] The overall impact of the absolute change in the efficiency of the high-pressure cylinder (ε1%) on the whole machine in step S13 (η) hczj The calculation formula is as follows:

[0113] η hczj =Δηhcr -Δη hcz

[0114] Δη hcr =Δη hp *ΔH hpt *F ms / (3600*N t )

[0115] Δη hcz =Δη hp *ΔH hpt *F hrh / (HR*N t )

[0116] Δη hp =(η hp -η hpt ) / η hp *100

[0117] η hpt =η hp -ε1

[0118] Where, Δη hcr This represents the direct impact of high-pressure cylinder efficiency on heat consumption, Δη. hcz The effect of high-pressure cylinder efficiency on reheater heat absorption is expressed as Δη. hp F represents the relative change in the efficiency of the high-pressure cylinder. ms N represents the main steam flow rate. t Indicates generator output, η hp η represents the design value of the high-pressure cylinder efficiency. hpt F represents the assumed value of the high-pressure cylinder efficiency, ε1 represents the change in the high-pressure cylinder efficiency, and F hrh Indicates the reheat steam flow rate;

[0119] The effect of the change in high-pressure cylinder efficiency on heat consumption ΔHR in step S14 HP The calculation formula is as follows:

[0120] ΔHR HP =ζ HP *HR / 100

[0121] ζ HP =Δη hczj / Δη hp

[0122] Where, ζ HP This indicates the proportion of the impact of the high-pressure cylinder efficiency change on the whole machine, and HR represents the turbine heat rate.

[0123] like Figure 2 As shown, the calculation process for the comprehensive impact of the absolute value change in the intermediate pressure cylinder efficiency on the whole machine includes the following steps:

[0124] S21. Obtain the hot revapor pressure and hot revapor temperature, and calculate the hot revapor enthalpy and hot revapor entropy.

[0125] S22. Obtain the intermediate pressure cylinder exhaust pressure and intermediate pressure cylinder exhaust temperature, and calculate the intermediate pressure cylinder exhaust enthalpy and the ideal intermediate pressure cylinder exhaust enthalpy by combining the heat reheat steam entropy. Further calculate the utilization energy and available energy of the intermediate pressure cylinder, and finally calculate the intermediate pressure cylinder efficiency design value.

[0126] S23. Based on the preset intermediate pressure cylinder efficiency, calculate the impact of the change in intermediate pressure cylinder efficiency on the heat consumption rate, and then calculate the comprehensive impact of the change in the absolute value of intermediate pressure cylinder efficiency on the whole machine.

[0127] S24. Finally, calculate the impact of the change in intermediate pressure cylinder efficiency on heat consumption.

[0128] In step S21, the enthalpy of reheated steam H hr and reheat steam entropy S hr The calculation formula is as follows:

[0129] H hr =StmPTH(P hr ,T hr ,1)

[0130] S hr =StmPTS(P hr ,T hr ,1)

[0131] Among them, P hr T represents the hot resteam pressure. hr Indicates the temperature of the hot resteam;

[0132] In step S22, the design value of the intermediate pressure cylinder efficiency η hr The calculation formula is as follows:

[0133] η hr =ΔH hr / ΔH hri

[0134] ΔH hr =H hr -H hrh

[0135] ΔH hri =H hr -H hrhi

[0136] H hrh =StmPTH(P hrc ,T hr ,1)

[0137] Hhrhi =StmPSH(P hrc ,S hr ,1)

[0138] Where, ΔH hr ΔH represents the energy utilized by the intermediate pressure cylinder. hri H represents the available energy of the intermediate pressure cylinder. hrh H represents the enthalpy of exhaust gas from the intermediate-pressure cylinder. hrhi P represents the ideal exhaust enthalpy of the intermediate-pressure cylinder. hr T represents the exhaust pressure of the intermediate pressure cylinder. hr This indicates the exhaust temperature of the intermediate pressure cylinder.

[0139] The overall impact η of the absolute change ε2% in the efficiency of the intermediate-pressure cylinder in step S23 on the whole machine. hrzj The calculation formula is as follows:

[0140] η hrzj =Δη hrr

[0141] Δη hrr =Δη hr *ΔH hr *F hrh / (3600*N t )

[0142] Δη hr =(η hr -η hrt ) / η hr *100

[0143] η hrt =η hr -ε2

[0144] Where, Δη hrr The direct impact of intermediate-pressure cylinder efficiency on heat consumption is represented by Δη. hr F represents the relative change in the efficiency of the intermediate-pressure cylinder. hrh N represents the reheat steam flow rate. t Indicates generator output, η hr η represents the design value of the intermediate pressure cylinder efficiency. hrt ε1 represents the assumed value of the intermediate pressure cylinder efficiency, and ε2 represents the change in the intermediate pressure cylinder efficiency.

[0145] The effect of the change in intermediate pressure cylinder efficiency on heat consumption ΔHR in step S24 IP The calculation formula is as follows:

[0146] ΔHR IP =ζ IP *HR / 100

[0147] ζ IP =Δηhrzj / Δη hr

[0148] Where, ζ IP This indicates the proportion of the impact of changes in intermediate-pressure cylinder efficiency on the overall machine, and HR represents the turbine heat rate.

[0149] like Figure 3 As shown, the calculation process for the comprehensive impact of the absolute value change in low-pressure cylinder efficiency on the entire machine includes the following steps:

[0150] S31. Obtain the low-pressure cylinder inlet steam pressure and low-pressure cylinder inlet steam temperature, and calculate the low-pressure cylinder inlet steam enthalpy and low-pressure cylinder inlet steam entropy.

[0151] S32. The exhaust enthalpy of the low-pressure cylinder is obtained by the energy balance iterative algorithm. The ideal exhaust enthalpy of the low-pressure cylinder is obtained by solving the exhaust pressure and inlet entropy of the low-pressure cylinder. The utilization energy and available energy of the low-pressure cylinder are further calculated, and finally the design value of the efficiency of the low-pressure cylinder is calculated.

[0152] S33. Based on the preset low-pressure cylinder efficiency, calculate the impact of the change in low-pressure cylinder efficiency on the heat rate, and then calculate the comprehensive impact of the change in the absolute value of low-pressure cylinder efficiency on the whole machine.

[0153] S34. Finally, calculate the impact of the change in low-pressure cylinder efficiency on heat consumption.

[0154] In step S31, the enthalpy of steam entering the low-pressure cylinder is H. ep and low-pressure cylinder inlet steam entropy S ep The calculation formula is as follows:

[0155] H ep =StmPTH(P ep ,T ep ,1)

[0156] S ep =StmPTS(P ep ,T ep ,1)

[0157] Among them, P ep T represents the low-pressure cylinder inlet pressure. ep Indicates the low-pressure cylinder inlet steam temperature;

[0158] In step S32, the design value of the low-pressure cylinder efficiency η hep The calculation formula is as follows:

[0159] η hep =ΔH ep / ΔH epi

[0160] ΔH ep =H ueep -H ueepi

[0161] ΔH epi =H ep -H ueepi

[0162] H ueepi =StmPSH(P ueep ,S ep ,1)

[0163] Where, ΔH ep ΔH represents the energy utilized by the low-pressure cylinder. epi H represents the available energy of the low-pressure cylinder. ueep H represents the enthalpy of low-pressure cylinder exhaust. ueepi P represents the ideal exhaust enthalpy of the low-pressure cylinder. ueep This indicates the exhaust pressure of the low-pressure cylinder.

[0164] The overall impact of the absolute change in the low-pressure cylinder efficiency ε3% on the whole machine in step S33. hepzj The calculation formula is as follows:

[0165] η hepzj =Δη hepr

[0166] Δη hepr =Δη hep *ΔH ep *F ueep / (3600*N t )

[0167] Δη hep =(η hep -η hept ) / η hep *100

[0168] η hept =η hep -ε3

[0169] Where, Δη hepr This represents the direct impact of low-pressure cylinder efficiency on heat consumption, Δη. hep F represents the relative change in low-pressure cylinder efficiency. ueep This indicates the steam flow rate entering the low-pressure cylinder, N. t Indicates generator output, η hep η represents the design value for low-pressure cylinder efficiency. hept ε3 represents the assumed value of the low-pressure cylinder efficiency, and ε3 represents the change in the low-pressure cylinder efficiency.

[0170] The effect of the change in low-pressure cylinder efficiency on heat consumption ΔHR in step S34 LP The calculation formula is as follows:

[0171] ΔHRLP =ζ LP *HR / 100

[0172] ζ LP =Δη hepzj / Δη hep

[0173] Where, ζ LP This indicates the proportion of the impact of changes in low-pressure cylinder efficiency on the overall machine, and HR represents the turbine heat rate.

[0174] In specific implementation, the THA operating condition of a certain CLN600-24.2 / 566 / 566 supercritical, single-stage intermediate reheat, three-cylinder four-exhaust, single-shaft, condensing steam turbine is calculated. In this embodiment, ε1=ε2=ε3=1%.

[0175] The impact of a 1% change in high-pressure cylinder efficiency on the overall heat consumption of the machine is shown in Table 1, with the relevant main parameters as follows:

[0176] Table 1. Key parameters related to the THA operating condition of the high-pressure cylinder section of the CLN600 steam turbine.

[0177]

[0178] Main steam enthalpy H ms =StmPTH(P ms ,T ms ,1)=StmPTH(242,566,1)=3398.78;

[0179] Main steam entropy S ms =StmPTS(P ms ,T ms ,1)=StmPTS(242,566,1)=6.2660;

[0180] High-pressure cylinder exhaust enthalpy H crht =StmPTH(P crh ,T crh ,1)=StmPTH(45.56,316.80,1)=2990.87;

[0181] Ideal exhaust enthalpy H of high-pressure cylinder crhi =StmPSH(P crh ,S ms ,1)=StmPSH(45.56,6.2660,1)=2935.92;

[0182] High-pressure cylinder utilizes energy ΔH hpt =H ms -H crht =3398.78 - 2990.87 = 407.91;

[0183] High-pressure cylinder available energy ΔH hpi =H ms -H crhi =3398.78 - 2935.92 = 462.86;

[0184] High-pressure cylinder efficiency design value η hp =ΔH hpt / ΔH hpi =407.91 / 462.86 = 0.8813;

[0185] Assumed high-pressure cylinder efficiency η hpt =η hp -ε1=0.8813-0.01=0.8713;

[0186] Relative change in high-pressure cylinder efficiency:

[0187] Δη hp =(η hp -η hpt ) / η hp *100=(0.8813-0.8713) / 0.8813*100=1.1347;

[0188] The direct impact of high-pressure cylinder efficiency on heat rate:

[0189] Δη hcr =Δη hp *ΔH hpt *F ms / (3600*N t = 1.1347 * 407.91 * 1799 / (3600 * 600) = 0.3855;

[0190] The effect of high-pressure cylinder efficiency on reheater heat absorption:

[0191] Δη hz =Δη hp *ΔH hpt *F hrh / (HR*N t = 1.1347 * 407.91 * 1524.6 / (7530 * 600) = 0.1562;

[0192] The overall impact of a 1% absolute change in the efficiency of the high-pressure cylinder on the entire machine:

[0193] η hczj =Δη hcr -Δη hcz =0.3855 - 0.1562 = 0.2293;

[0194] The impact of a 1% relative change in the efficiency of the high-pressure cylinder on the overall machine:

[0195] ζ HP =Δη hczj / Δη hp =0.2293 / 1.1347 = 0.2021;

[0196] The impact of high-pressure cylinder efficiency changes on heat consumption:

[0197] ΔHR HP =ζ HP *HR / 100=0.2021*7530 / 100=15.2168.

[0198] The impact of a 1% change in intermediate-pressure cylinder efficiency on the overall heat consumption of the machine is shown in Table 2, with the relevant main parameters as follows:

[0199] Table 2. Key parameters related to the THA operating condition of the intermediate pressure cylinder section of the CLN600 steam turbine.

[0200]

[0201] enthalpy of reheat steam H hr =StmPTH(P hr ,T hr ,1)=StmPTH(48.39,566,1)=3589.33;

[0202] Entropy S of reheat steam hr =StmPTS(P hr ,T hr ,1)=StmPTS(48.39,566,1)=7.1846;

[0203] Intermediate-pressure cylinder exhaust enthalpy H hrh =StmPTH(P hrc ,T hr ,1)=StmPTH(11.14,474.60,1)=3422.74;

[0204] Ideal exhaust enthalpy H of intermediate pressure cylinder hrhi =StmPSH(P hrc ,S hr ,1)=StmPSH(11.14,7.1846,1)=3115.61;

[0205] Medium-pressure cylinder utilizes energy ΔH hr =H hr -H hrh =H hr -H hrh =3589.33 - 3422.74 = 166.60;

[0206] Medium-pressure cylinder available energy ΔH hri =H hr -H hrhi =3589.33 - 3115.61 = 473.72;

[0207] Intermediate pressure cylinder efficiency design value η hr =ΔH hr / ΔH hri =166.60 / 473.72=0.3517;

[0208] Assumed efficiency value η of intermediate pressure cylinder hrt =η hr -ε2=0.3517-0.01=0.3417;

[0209] Relative changes in intermediate pressure cylinder efficiency:

[0210] Δη hr =(η hr -η hrt ) / η hr *100=(0.3517-0.3417) / 0.3517*100=2.8435

[0211] The direct impact of intermediate-pressure cylinder efficiency on heat consumption:

[0212] Δη hrr =Δη hr *ΔH hr *F hrh / (3600*N t = 2.8435 * 166.60 * 1524.6 / (3600 * 600) = 0.3344;

[0213] The overall impact of a 1% absolute change in the efficiency of the intermediate-pressure cylinder on the entire machine:

[0214] η hrzj =Δη hrr =0.3344;

[0215] The impact of a 1% change in intermediate pressure cylinder efficiency on the overall machine:

[0216] ζ IP =Δη hrzj / Δη hr =0.3344 / 2.8435 = 0.1176;

[0217] The impact of changes in intermediate-pressure cylinder efficiency on heat consumption:

[0218] ΔHR IP =ζ IP*HR / 100=0.1176*7530 / 100=8.8548.

[0219] The impact of a 1% change in low-pressure cylinder efficiency on the overall heat consumption of the machine is shown in Table 3, with the relevant main parameters as follows:

[0220] Table 3. Key parameters related to the THA operating condition of the low-pressure cylinder section of the CLN600 steam turbine.

[0221]

[0222] Low-pressure cylinder inlet steam enthalpy H ep =StmPTH(P ep ,T ep ,1)=StmPTH(10.43,369.79,1)=3199.39;

[0223] Low-pressure cylinder inlet steam entropy S ep =StmPTS(P ep ,T ep ,1)=StmPTS(10.43,369.79,1)=7.3488;

[0224] The low-pressure cylinder exhaust enthalpy H is obtained through energy balance iteration. ueep =2318.6;

[0225] Ideal exhaust enthalpy H of low-pressure cylinder ueepi =StmPSH(P ueep ,S ep ,1)=StmPSH(0.049,7.3488,1)=2238.48;

[0226] Low-pressure cylinder utilizes energy ΔH ep =H ueep -H ueepi =3199.39 - 2318.60 = 880.79;

[0227] Low-pressure cylinder available energy ΔH epi =H ep -H ueepi =3199.39-2238.48=960.91;

[0228] Low-pressure cylinder efficiency design value η hep =ΔH ep / ΔH epi =880.79 / 960.91=0.9166;

[0229] Assumed low-pressure cylinder efficiency η hept =η hep -ε3=0.9166-0.01=0.9066;

[0230] Relative change in low-pressure cylinder efficiency:

[0231] Δη hep =(η hep -η hept ) / η hep *100=(0.9166-0.9066) / 0.9166*100=1.0910;

[0232] The direct impact of low-pressure cylinder efficiency on heat consumption:

[0233] Δη hepr =Δη hep *ΔH ep *F ueep / (3600*Nt)=1.0910*880.79*1202.1 / (3600*600)=0.5348;

[0234] The overall impact of the absolute change ε% in low-pressure cylinder efficiency on the whole machine:

[0235] η hepzj =Δη hepr =0.5348;

[0236] The impact of a 1% change in low-pressure cylinder efficiency on the overall machine:

[0237] ζ LP =Δη hepzj / Δη hep =0.5348 / 1.0910 = 0.4902;

[0238] The impact of a 1% change in low-pressure cylinder efficiency on heat consumption:

[0239] ΔHR LP =ζ LP *HR / 100=0.4902*7530 / 100=36.9094.

[0240] For calculating the impact of a 1% change in cylinder efficiency (high, medium, and low) on heat consumption, the method of this invention is compared with... Figure 4 The data from the "Correction Curves of High, Medium and Low In-Cylinder Efficiency on Heat Consumption Rate" in the thermodynamic characteristic report of a certain steam turbine manufacturer (see Table 4) were compared and verified. The results showed good agreement, indicating the correctness of the method of the present invention. Table 4 is shown in detail below:

[0241] Table 4. Impact of a 1% Change in Cylinder Efficiency on Heat Consumption

[0242]

[0243] Furthermore, it should be noted that the specific embodiments described in this specification may be given different names, and the above description is merely illustrative of the structure of the present invention. All equivalent or simple variations made based on the construction, features, and principles of the present invention are included within the scope of protection of the present invention. Those skilled in the art can make various modifications or additions to the described specific examples or adopt similar methods, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, all of which should fall within the scope of protection of the present invention.

Claims

1. A method for assessing the impact of turbine cylinder efficiency on the overall turbine under multiple turbine models and variable operating conditions, characterized in that, Using the equivalent enthalpy drop method and based on the small deviation theory, the comprehensive impact of the absolute values ​​of high-pressure cylinder efficiency, intermediate-pressure cylinder efficiency, and low-pressure cylinder efficiency on the whole unit is calculated, thereby obtaining the evaluation results of the impact of cylinder efficiency changes on the heat rate and electric power of the turbine unit. The calculation process for the comprehensive impact of the absolute value change in the high-pressure cylinder efficiency on the whole machine includes the following steps: S11. Obtain the main steam pressure and main steam temperature, and calculate the main steam enthalpy and main steam entropy; S12. Obtain the exhaust pressure and temperature of the high-pressure cylinder, calculate the exhaust enthalpy and ideal exhaust enthalpy of the high-pressure cylinder by combining the main steam entropy, further calculate the utilization energy and available energy of the high-pressure cylinder, and finally obtain the design value of the high-pressure cylinder efficiency. S13. Based on the preset high-pressure cylinder efficiency, calculate the impact of the change in high-pressure cylinder efficiency on the heat consumption rate and the heat absorption of the reheater, and then calculate the comprehensive impact of the change in the absolute value of the high-pressure cylinder efficiency on the whole machine. S14. Finally, calculate the impact of the high-pressure cylinder efficiency change on heat consumption. The main vapor enthalpy in step S11 H ms and main steam entropy S ms The calculation formula is as follows: ； ； in, P ms Indicates the main steam pressure. T ms Indicates the main steam temperature. The function representing enthalpy calculation. This represents the entropy calculation function; The high-pressure cylinder efficiency design value in step S12 η hp The calculation formula is as follows: ； ； ； ； ； in, ΔH hpt This indicates the energy utilized by the high-pressure cylinder. ΔH hpi Indicates the available energy of the high-pressure cylinder. H crht This indicates the enthalpy of the high-pressure cylinder exhaust. H crhi This represents the ideal exhaust enthalpy of the high-pressure cylinder. P crh This indicates the exhaust pressure of the high-pressure cylinder. T crh This indicates the exhaust temperature of the high-pressure cylinder. This represents the function for calculating the ideal exhaust enthalpy. The change in absolute value of high-pressure cylinder efficiency in step S13 % Overall impact on the machine η hczj The calculation formula is as follows: ； ； ； ； ； in, Δη hcr This indicates the direct impact of high-pressure cylinder efficiency on heat consumption. Δη hcz This indicates the effect of high-pressure cylinder efficiency on reheater heat absorption. Δη hp This indicates the relative change in the efficiency of the high-pressure cylinder. F ms Indicates the main steam flow rate. N t Indicates generator output. η hp This represents the design value for the high-pressure cylinder efficiency. η hpt This represents the assumed efficiency value of the high-pressure cylinder. This indicates the change in the efficiency of the high-pressure cylinder. Indicates the reheat steam flow rate; The impact of high-pressure cylinder efficiency change on heat consumption in step S14 The calculation formula is as follows: ； ； in, This indicates the proportion of the impact of changes in the high-pressure cylinder efficiency on the overall machine. HR This indicates the heat consumption rate of the steam turbine.

2. The method for assessing the impact of turbine cylinder efficiency on the whole machine based on multi-model and variable operating condition operation as described in claim 1, characterized in that, The calculation process for the comprehensive impact of the change in the absolute value of the intermediate pressure cylinder efficiency on the whole machine includes the following steps: S21. Obtain the hot revapor pressure and hot revapor temperature, and calculate the hot revapor enthalpy and hot revapor entropy. S22. Obtain the intermediate pressure cylinder exhaust pressure and intermediate pressure cylinder exhaust temperature, and calculate the intermediate pressure cylinder exhaust enthalpy and the ideal intermediate pressure cylinder exhaust enthalpy by combining the heat reheat steam entropy. Further calculate the utilization energy and available energy of the intermediate pressure cylinder, and finally calculate the intermediate pressure cylinder efficiency design value. S23. Based on the preset intermediate pressure cylinder efficiency, calculate the impact of the change in intermediate pressure cylinder efficiency on the heat consumption rate, and then calculate the comprehensive impact of the change in the absolute value of intermediate pressure cylinder efficiency on the whole machine. S24. Finally, calculate the impact of the change in intermediate pressure cylinder efficiency on heat consumption.

3. The method for assessing the impact of turbine cylinder efficiency on the whole machine based on multi-model and variable operating condition operation, as described in claim 2, is characterized in that... The enthalpy of reheat steam in step S21 H hr and reheat steam entropy S hr The calculation formula is as follows: ； ； in, P hr Indicates the hot resteam pressure. T hr Indicates the temperature of the hot resteam; The design value of the intermediate pressure cylinder efficiency in step S22 η hr The calculation formula is as follows: ； ； ； ； ； in, ΔH hr This indicates the energy utilization of the intermediate pressure cylinder. ΔH hri Indicates the available energy of the intermediate pressure cylinder. H hrh This indicates the enthalpy of the exhaust steam from the intermediate-pressure cylinder. H hrhi This represents the ideal exhaust enthalpy of the intermediate-pressure cylinder. P hrc This indicates the exhaust pressure of the intermediate pressure cylinder. T hr This indicates the exhaust temperature of the intermediate pressure cylinder.

4. The method for assessing the impact of turbine cylinder efficiency on the whole machine based on multi-model and variable operating condition operation as described in claim 3, characterized in that, The change in absolute value of intermediate pressure cylinder efficiency in step S23 % Overall impact on the whole machine η hrzj The calculation formula is as follows: ； ； ； ； in, Δη hrr This indicates the direct impact of intermediate-pressure cylinder efficiency on heat consumption. Δη hr This indicates the relative change in the efficiency of the intermediate-pressure cylinder. F hrh Indicates the reheat steam flow rate. N t Indicates generator output. η hr This represents the design value for the intermediate pressure cylinder efficiency. η hrt This represents the assumed value for the efficiency of the intermediate-pressure cylinder. This indicates the change in the efficiency of the intermediate-pressure cylinder; The impact of the change in intermediate pressure cylinder efficiency on heat consumption in step S24 The calculation formula is as follows: ； ； in, This indicates the proportion of the impact of changes in the intermediate-pressure cylinder efficiency on the overall machine. HR This indicates the heat consumption rate of the steam turbine.

5. The method for assessing the impact of turbine cylinder efficiency on the whole machine based on multi-model and variable operating condition operation as described in claim 1, characterized in that, The calculation process for the comprehensive impact of the change in the absolute value of the low-pressure cylinder efficiency on the whole machine includes the following steps: S31. Obtain the low-pressure cylinder inlet steam pressure and low-pressure cylinder inlet steam temperature, and calculate the low-pressure cylinder inlet steam enthalpy and low-pressure cylinder inlet steam entropy. S32. The exhaust enthalpy of the low-pressure cylinder is obtained by the energy balance iterative algorithm. The ideal exhaust enthalpy of the low-pressure cylinder is obtained by solving the exhaust pressure and inlet entropy of the low-pressure cylinder. The utilization energy and available energy of the low-pressure cylinder are further calculated, and finally the design value of the efficiency of the low-pressure cylinder is calculated. S33. Based on the preset low-pressure cylinder efficiency, calculate the impact of the change in low-pressure cylinder efficiency on the heat rate, and then calculate the comprehensive impact of the change in the absolute value of low-pressure cylinder efficiency on the whole machine. S34. Finally, calculate the impact of the change in low-pressure cylinder efficiency on heat consumption.

6. The method for assessing the impact of turbine cylinder efficiency on the whole machine based on multi-model and variable operating condition operation as described in claim 5, characterized in that, In step S31, the enthalpy of the low-pressure cylinder inlet steam... H ep and low-pressure cylinder intake entropy S ep The calculation formula is as follows: ； ； in, P ep This indicates the inlet steam pressure of the low-pressure cylinder. T ep Indicates the low-pressure cylinder inlet steam temperature; The design value of low-pressure cylinder efficiency in step S32 η hep The calculation formula is as follows: ； ； ； ； in, ΔH ep This indicates the energy utilized by the low-pressure cylinder. ΔH epi This indicates the available energy of the low-pressure cylinder. H ueep This indicates the enthalpy of the low-pressure cylinder exhaust. H ueepi This indicates the ideal exhaust enthalpy of the low-pressure cylinder. P ueep This indicates the exhaust pressure of the low-pressure cylinder.

7. The method for assessing the impact of turbine cylinder efficiency on the whole machine based on multi-model and variable operating condition operation as described in claim 6, characterized in that, The change in absolute value of low-pressure cylinder efficiency in step S33 % Overall impact on the whole machine η hepzj The calculation formula is as follows: ； ； ； ； in, Δη hepr This indicates the direct impact of low-pressure cylinder efficiency on heat consumption. Δη hep This indicates the relative change in the efficiency of the low-pressure cylinder. F ueep This indicates the steam flow rate entering the low-pressure cylinder. N t Indicates generator output. η hep This indicates the design value for low-pressure cylinder efficiency. η hept This represents the assumed value for the low-pressure cylinder efficiency. This indicates the change in low-pressure cylinder efficiency; The impact of low-pressure cylinder efficiency change on heat consumption in step S34 The calculation formula is as follows: ； ； in, This indicates the proportion of the impact of changes in low-pressure cylinder efficiency on the overall machine. HR This indicates the heat consumption rate of the steam turbine.

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