Gas turbine combustion state optimization control method and system

Abstract

The invention discloses a gas turbine combustion state optimization control method and system, and relates to the technical field of gas turbine combustion state optimization control. The operation parameters comprise but are not limited to inlet pressure, turbine exhaust pressure and turbine exhaust temperature; and a control instruction is generated, and the turbine inlet temperature is adjusted to tend to the turbine inlet temperature limit value under the safety condition. According to the method, the defect that the turbine inlet temperature of the gas turbine cannot be directly measured is overcome, the calculation formula of the total pressure loss coefficient of the combustion chamber of the gas turbine and the gas specific heat ratio of the outlet of the combustion chamber under different loads is fitted, and the calculation precision of the turbine inlet temperature is improved.

Description

Technical Field

[0001] The present invention relates to the technical field, and in particular to a method and system for optimizing control of combustion state of a gas turbine. Background Art

[0002] With the continuous growth of global energy demand and the improvement of environmental protection awareness, gas turbines, as an efficient and clean power generation equipment, play an increasingly important role in the energy field. Gas turbines are widely used in power generation, cogeneration, industrial drive and other fields due to their high efficiency, low emissions, fast start-up and flexible operation.

[0003] The operating temperature of the combustion chamber of a gas turbine is very high, and the operating temperature of the combustion chamber of a class F gas turbine is basically above 1350°C. It is very difficult to measure parameters such as combustion pressure pulsation and combustion temperature that characterize the combustion state in the combustion chamber, and the combustion chamber outlet temperature has not yet been directly measured in the gas turbines in service. However, the outlet temperature of the combustion chamber of a gas turbine directly affects the safety of the combustion chamber and turbine components, and is one of the key factors affecting the performance and life of the gas turbine. In actual production operation, gas turbines often have failures such as bulging, cracking, burning through of the combustion chamber flame tube, and ablation of turbine blade components. This is mainly due to the high outlet temperature of the combustion chamber. The control system of the gas turbine in service generally uses the turbine exhaust temperature as the control variable, so that the operating personnel cannot obtain the outlet temperature of the combustion chamber in real time, and cannot accurately diagnose and optimize the combustion state, causing the gas turbine to work for a long time in the state of over-limit outlet temperature of the combustion chamber, and eventually the combustion chamber or turbine components are damaged. In response to these shortcomings, we have invented a method and system for optimizing the combustion state of a gas turbine. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above problems or problems existing in the prior art, the present invention is proposed.

[0006] Therefore, the technical problem solved by the present invention is that the combustion state cannot be accurately diagnosed and optimally controlled, causing the gas turbine to operate for a long time in a state where the combustion chamber outlet temperature exceeds the limit, and eventually the combustion chamber or turbine components are damaged.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for optimizing the combustion state of a gas turbine, comprising obtaining operating parameters of a combustion chamber of a gas turbine generator set and establishing a calculation formula for a turbine inlet temperature, wherein the operating parameters include but are not limited to a combustion chamber inlet pressure, a turbine exhaust pressure, and a turbine exhaust temperature;

[0008] Determine the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas and calculate the turbine inlet temperature under the current operating conditions;

[0009] Acquiring combustion pressure pulsation data, and comparing the combustion pressure pulsation amplitude with a set alarm value to form a first result;

[0010] Based on the first result, obtaining NOx emission data and comparing it with the emission standard to form a second result;

[0011] Based on the second result, the obtained turbine inlet temperature is compared with the set value and the IGV opening is adjusted;

[0012] Generate control instructions to adjust the turbine inlet temperature toward the turbine inlet temperature limit under safe conditions.

[0013] As a preferred solution of the gas turbine combustion state optimization control method of the present invention, the turbine inlet temperature calculation formula is expressed as:

[0014]

[0015] Among them, σ c is the total pressure loss coefficient of the gas turbine combustion chamber; n is the specific heat ratio of the gas at the outlet of the gas turbine combustion chamber; η t is the turbine efficiency of the gas turbine; P2 is the combustion chamber inlet pressure; P4 is the turbine exhaust pressure; T4 is the turbine exhaust temperature; T3 is the turbine inlet temperature.

[0016] As a preferred solution of the gas turbine combustion state optimization control method of the present invention, the determination of the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas includes:

[0017] Establish a three-dimensional combustion calculation numerical model of the gas turbine combustor through flow field analysis software such as ANSYS;

[0018] Establish a Thermoflow gas turbine heat balance calculation model and calculate the inlet and outlet boundary parameters of the combustion chamber of the gas turbine from startup to full load operation, and obtain the boundary parameters of the gas turbine under typical load; the boundary parameters include but are not limited to the mass flow rate of air and fuel at the inlet of the combustion chamber, temperature and the outlet pressure of the combustion chamber; the typical load is selected and determined according to the regular operating load point of the gas turbine power plant;

[0019] Based on the combustion chamber inlet and outlet boundary parameters, the three-dimensional combustion calculation numerical model is used to calculate and obtain the results of the gas pressure field, temperature field and velocity field in the combustion chamber of the gas turbine under typical load;

[0020] Based on the results, the total inlet and outlet pressure and outlet gas specific heat ratio of the gas turbine combustion chamber under typical load are analyzed and obtained, and the total pressure loss coefficient of the combustion chamber is calculated and expressed as:

[0021]

[0022] Among them, P * 2 is the total pressure at the combustion chamber inlet, P * 3 is the total pressure at the combustion chamber outlet, σ c is the total pressure loss coefficient of the combustion chamber;

[0023] The curve fitting method is used to fit the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas with relative load as the independent variable, and the calculation formulas of the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas n are respectively obtained, which are expressed as:

[0024] σ c =f(w)

[0025] n=g(w)

[0026] Wherein, n is the specific heat ratio of the combustion chamber outlet gas, w is the independent variable relative load, f(w) is the calculation function of the total pressure loss coefficient of the combustion chamber obtained by fitting, and g(w) is the calculation function of the specific heat ratio of the combustion chamber outlet gas obtained by fitting.

[0027] As a preferred solution of the gas turbine combustion state optimization control method of the present invention, the acquisition of combustion pressure pulsation data and the comparison of the combustion pressure pulsation amplitude with the set alarm value to form a first result include:

[0028] Obtain multiple measurements of combustion pressure pulsation P from the operating data of the gas turbine generator set i , where i = 1, 2, ... m, m is the number of measurements;

[0029] Calculate the average of the pressure pulsation measurements, expressed as:

[0030]

[0031] in, is the average pressure, P i is the i-th pressure pulsation measurement value;

[0032] The combustion pressure pulsation amplitude is calculated and expressed as:

[0033]

[0034] Among them, ΔP actual is the combustion pressure pulsation amplitude actually calculated, Pi is the ith pressure pulsation measurement value, is the average pressure, m is the number of measurements, and α is the correction coefficient;

[0035] Calculate the standard deviation of the combustion pressure pulsation, expressed as:

[0036]

[0037] Among them, σ P is the standard deviation of combustion pressure pulsation; P i is the i-th pressure pulsation measurement value;

[0038] The combustion pressure pulsation amplitude is compared with the alarm value through a comprehensive judgment formula, which is expressed as:

[0039]

[0040] Among them, δ is the judgment result, ΔP actual is the actual calculated combustion pressure pulsation amplitude, ΔP threshold is the set alarm value, σ P is the standard deviation of combustion pressure pulsation;

[0041] The forming of the first result includes that when δ>1, it indicates that the combustion pressure pulsation amplitude exceeds the alarm value, and an instruction to increase the on-duty fuel flow by 0.1% is issued; when δ≤1, it indicates that the combustion pressure pulsation amplitude does not exceed the alarm value, and the fuel flow does not need to be adjusted.

[0042] As a preferred solution of the gas turbine combustion state optimization control method of the present invention, the method based on the first result includes:

[0043] When the combustion pressure pulsation amplitude does not exceed the alarm value set in the engine control system, obtain NOx emission data and compare it with the emission standards;

[0044] The obtaining of NOx emission data and comparing with emission standards includes:

[0045] Obtain relevant parameters from the operating data of the gas turbine generator set;

[0046] The NOx emissions are compared with the local emission standards through a comprehensive comparison formula, expressed as:

[0047]

[0048] Among them, NOx actual is the NOx emission, σ is the judgment result, NOxactual is the actual measured NOx emission, NOx standard for local emission standards;

[0049] The forming of the second result includes that when σ>0, it indicates that NOx emissions exceed the local emission standard, and an instruction to reduce the fuel flow by 0.1% is issued; when σ≤0, it indicates that NOx emissions do not exceed the local emission standard, and the fuel flow does not need to be adjusted.

[0050] As a preferred solution of the gas turbine combustion state optimization control method of the present invention, the method based on the second result includes:

[0051] When NOx emissions do not exceed the local emission standards, the calculated turbine inlet temperature T3 is compared with the set value T3r in the gas turbine control system;

[0052] The adjusting of the IGV opening comprises:

[0053] If T3r-T3 is less than the set threshold, it is further determined whether T3r-T3 is less than 0; if it is less than 0 and the IGV opening is not fully opened, an instruction to increase the IGV opening by 1% is output; if the IGV opening is fully opened, an instruction to reduce the fuel flow by 0.1% is output;

[0054] If T3r-T3 is less than the set threshold but not less than 0, the IGV and fuel flow operating parameters remain unchanged;

[0055] If T3r-T3 is greater than the set threshold, an instruction to reduce the IGV opening is output to increase the combustion chamber outlet temperature (turbine inlet temperature) by reducing the air flow entering the gas turbine.

[0056] As a preferred solution of the gas turbine combustion state optimization control method of the present invention, wherein: the generating control instruction to adjust the turbine inlet temperature to the turbine inlet temperature limit under safe conditions includes:

[0057] After executing the control instruction, the turbine inlet temperature is calculated in real time, and combined with the changes in combustion pressure pulsation and NOx emission data, new IGV and fuel flow control instructions are generated immediately until the turbine inlet temperature T3 satisfies: T3r-T3 is less than the set threshold but greater than 0, that is, to ensure that the turbine inlet temperature T3 tends to the turbine inlet temperature limit T3r under safe conditions.

[0058] Another object of the present invention is to provide a system for optimizing the control of the combustion state of a gas turbine, which can generate control instructions and adjust the turbine inlet temperature toward the turbine inlet temperature limit under safe conditions, thereby solving the problem that current gas turbines cannot accurately diagnose and optimize the combustion state.

[0059] As a preferred solution of the system for optimizing the combustion state of a gas turbine according to the present invention, it includes: an establishment module, a determination module, a first judgment module, a second judgment module, a third judgment module, and an adjustment module;

[0060] The establishment module is used to obtain the combustion chamber operating parameters of the gas turbine generator set and establish a turbine inlet temperature calculation formula, wherein the operating parameters include but are not limited to the combustion chamber inlet pressure, the turbine exhaust pressure, and the turbine exhaust temperature;

[0061] The determination module is used to determine the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas and calculate the turbine inlet temperature under the current operating conditions;

[0062] The first judgment module is used to obtain combustion pressure pulsation data and compare the combustion pressure pulsation amplitude with a set alarm value to form a first result;

[0063] The second judgment module is used to obtain NOx emission data based on the first result and compare it with the emission standard to form a second result;

[0064] The third judgment module is used to compare the obtained turbine inlet temperature with the set value based on the second result and adjust the IGV opening;

[0065] The adjustment module is used to generate a control instruction to adjust the turbine inlet temperature toward the turbine inlet temperature limit value under a safe condition.

[0066] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement a method for optimizing the combustion state of a gas turbine.

[0067] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for optimizing the combustion state of a gas turbine.

[0068] Beneficial effects of the present invention: The combustion state of the gas turbine is mainly reflected by combustion pressure pulsation, NOx emissions and combustion chamber outlet temperature (turbine inlet temperature). Due to the high combustion chamber outlet temperature, it is currently impossible to measure directly. The traditional combustion state adjustment method only refers to combustion pressure pulsation, NOx emissions and turbine exhaust temperature, and cannot achieve precise control of the combustion state. This solution establishes a method for calculating the turbine inlet temperature based on the turbine exhaust temperature, and fits the total pressure loss coefficient of the combustion chamber under different loads and the calculation formula for the specific heat ratio of the combustion chamber outlet gas. It can accurately calculate the outlet temperature of the gas turbine combustion chamber under different loads, and through comprehensive judgment of combustion pressure pulsation, NOx emissions and combustion chamber outlet temperature, output IGV and fuel flow control instructions in real time, and try to increase the combustion chamber outlet temperature as much as possible while ensuring the safe and stable operation of the combustion chamber, thereby improving the efficiency of the cycle power generation of the gas generator set. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0070] Figure 1 A three-dimensional solid model diagram of the combustion chamber for the gas turbine combustion state optimization control method.

[0071] Figure 2 This is a three-dimensional numerical model diagram of the combustion chamber.

[0072] Figure 3 This is a diagram of heat balance calculation results for a thermoflow gas turbine under 100% typical load.

[0073] Figure 4 This is the result diagram of the pressure field in the center section of the combustion chamber under 100% typical load.

[0074] Figure 5 This is the temperature field result diagram of the central section of the combustion chamber under 100% typical load.

[0075] Figure 6 This is the velocity field result diagram of the central section of the combustion chamber under 100% typical load.

[0076] Figure 7 This is a logical judgment diagram of the gas turbine combustion state optimization control system.

[0077] Figure 8 It is a schematic diagram of the overall device of the computer. DETAILED DESCRIPTION

[0078] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0079] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0080] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0081] Example 1

[0082] Reference Figures 1 to 8 , as one embodiment of the present invention, provides a method for optimizing the combustion state of a gas turbine, comprising:

[0083] S1: Obtain operating parameters of a combustion chamber of a gas turbine generator set and establish a calculation formula for turbine inlet temperature, wherein the operating parameters include but are not limited to inlet pressure, turbine exhaust pressure, and turbine exhaust temperature.

[0084] Furthermore, the turbine inlet temperature calculation formula is expressed as:

[0085]

[0086] Among them, σ c is the total pressure loss coefficient of the gas turbine combustion chamber; n is the specific heat ratio of the gas at the outlet of the gas turbine combustion chamber; η t is the turbine efficiency of the gas turbine; P2 is the combustion chamber inlet pressure; P4 is the turbine exhaust pressure; T4 is the turbine exhaust temperature; T3 is the turbine inlet temperature.

[0087] S2: Determine the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas and calculate the turbine inlet temperature under the current operating conditions.

[0088] Furthermore, the determination of the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas includes:

[0089] Establish a three-dimensional combustion calculation numerical model of the gas turbine combustor through flow field analysis software such as ANSYS;

[0090] Thermoflow power plant heat balance analysis professional software is used to establish a Thermoflow gas turbine heat balance calculation model for the gas turbine model used in the gas power plant. The boundary parameters of the calculation model are set according to the historical operation data of the gas turbine, and the accuracy of the calculation model is verified using the historical operation data of the gas turbine. The verified Thermoflow gas turbine heat balance calculation model is used to calculate the combustion chamber inlet and outlet boundary parameters of the gas turbine from startup to full load operation.

[0091] Considering that gas turbines emit high pollutants when running at low load, gas turbine generator sets generally operate in the range of 50% to 100%. Therefore, the established Thermoflow gas turbine heat balance calculation model is used to calculate the boundary parameters such as the gas turbine combustion chamber inlet air and fuel mass flow, temperature and combustion chamber outlet pressure under typical loads such as 50%, 60%, 70%, 80%, 90% and 100%. The typical load can be selected and determined according to the load point that the gas turbine power plant often operates.

[0092] In the established three-dimensional combustion calculation numerical model of the gas turbine combustion chamber, the combustion chamber inlet and outlet boundary parameters are set according to the calculated parameters, and the gas pressure field, temperature field and velocity field in the gas turbine combustion chamber under typical loads of 50%, 60%, 70%, 80%, 90% and 100% are calculated;

[0093] According to the calculation results, the total pressure P at the inlet of the gas turbine combustion chamber under typical loads such as 50%, 60%, 70%, 80%, 90% and 100% is obtained. * 2. Total pressure at the combustion chamber outlet P * 3 and the specific heat ratio n of the combustion chamber outlet gas, the total pressure loss coefficient of the combustion chamber is calculated and expressed as:

[0094]

[0095] Among them, P * 2 is the total pressure at the combustion chamber inlet, P * 3 is the total pressure at the combustion chamber outlet, σ c is the total pressure loss coefficient of the combustion chamber;

[0096] The curve fitting method is used to fit the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas with relative load as the independent variable, and the calculation formulas of the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas n are respectively obtained, which are expressed as:

[0097] σ c =f(w)

[0098] n=g(w)

[0099] Wherein, n is the specific heat ratio of the combustion chamber outlet gas, w is the independent variable relative load, f(w) is the calculation function of the total pressure loss coefficient of the combustion chamber obtained by fitting, and g(w) is the calculation function of the specific heat ratio of the combustion chamber outlet gas obtained by fitting.

[0100] Furthermore, the calculation to obtain the turbine inlet temperature under the current operating conditions includes the gas turbine turbine exhaust temperature T4, the gas turbine compressor exhaust pressure P2, and the gas turbine turbine exhaust pressure P4 obtained from the gas turbine generator set operating data, and the turbine inlet temperature T3 is calculated in combination with the above formula.

[0101] S3: Acquire combustion pressure pulsation data, and compare the combustion pressure pulsation amplitude with the set alarm value to form a first result.

[0102] Furthermore, combustion pressure pulsation data is obtained from the operating data of the gas turbine generator set to determine whether the combustion pressure pulsation amplitude exceeds the alarm value set in the gas turbine control system. If it exceeds, the control system issues an instruction to increase the duty fuel flow by 0.1%.

[0103] Specifically, the obtaining of combustion pressure pulsation data and comparing the combustion pressure pulsation amplitude with a set alarm value to form a first result includes:

[0104] Obtain multiple measurements of combustion pressure pulsation P from the operating data of the gas turbine generator set i , where i = 1, 2, ... m, m is the number of measurements;

[0105] Calculate the average of the pressure pulsation measurements, expressed as:

[0106]

[0107] in, is the average pressure, P i is the i-th pressure pulsation measurement value;

[0108] The combustion pressure pulsation amplitude is calculated and expressed as:

[0109]

[0110] Among them, ΔP actual is the combustion pressure pulsation amplitude actually calculated, Pi is the ith pressure pulsation measurement value, is the average pressure, m is the number of measurements, and α is the correction coefficient;

[0111] It should be noted that the fourth power processing is used to calculate the degree of discreteness of the data, which is more sensitive to extreme values ​​than the square processing (i.e., variance or standard deviation). By using the fourth power of the pressure difference as part of the calculation, the pressure measurements that are far from the average value can be amplified to better reflect the violent fluctuations that may exist in the combustion process. The result of this processing method is greater sensitivity to abnormal points in the data (such as sudden pressure peaks or valleys) while ensuring the smoothness and stability of the data. Moreover, abnormal pressure fluctuations during the combustion process may indicate potential problems or failures, which can be better judged.

[0112] Calculate the standard deviation of the combustion pressure pulsation, expressed as:

[0113]

[0114] Among them, σ P is the standard deviation of combustion pressure pulsation; P i is the i-th pressure pulsation measurement value;

[0115] The combustion pressure pulsation amplitude is compared with the alarm value through a comprehensive judgment formula, which is expressed as:

[0116]

[0117] Among them, δ is the judgment result, ΔP actual is the actual calculated combustion pressure pulsation amplitude, ΔP threshold is the set alarm value, σ P is the standard deviation of combustion pressure pulsation;

[0118] The forming of the first result includes that when δ>1, it indicates that the combustion pressure pulsation amplitude exceeds the alarm value, and an instruction to increase the on-duty fuel flow by 0.1% is issued; when δ≤1, it indicates that the combustion pressure pulsation amplitude does not exceed the alarm value, and the fuel flow does not need to be adjusted.

[0119] S4: Based on the first result, obtain NOx emission data and compare it with the emission standard to form a second result.

[0120] Furthermore, if the combustion pressure pulsation amplitude does not exceed the alarm value set in the gas turbine control system, the NOx emission data is obtained from the gas turbine generator set operating data to determine whether the NOx emission exceeds the local emission standards. If it exceeds, the control system issues a command to reduce the on-duty fuel flow by 0.1%.

[0121] Specifically, the method based on the first result includes:

[0122] When the combustion pressure pulsation amplitude does not exceed the alarm value set in the engine control system, obtain NOx emission data and compare it with the emission standards;

[0123] The obtaining of NOx emission data and comparing with emission standards includes:

[0124] Obtain relevant parameters from the operating data of the gas turbine generator set;

[0125] The NOx emissions are compared with the local emission standards through a comprehensive comparison formula, expressed as:

[0126]

[0127] Among them, NOx actual is the NOx emission, σ is the judgment result, NOx actual is the actual measured NOx emission, NOx standard for local emission standards;

[0128] The forming of the second result includes that when σ>0, it indicates that NOx emissions exceed the local emission standard, and an instruction to reduce the fuel flow by 0.1% is issued; when σ≤0, it indicates that NOx emissions do not exceed the local emission standard, and the fuel flow does not need to be adjusted.

[0129] S5: Based on the second result, the obtained turbine inlet temperature is compared with the set value, and the IGV opening is adjusted.

[0130] It should be noted that the second result includes:

[0131] When NOx emissions do not exceed the local emission standards, the calculated turbine inlet temperature T3 is compared with the set value T3r in the gas turbine control system;

[0132] The adjusting of the IGV opening comprises:

[0133] If T3r-T3 is less than the set threshold, it is further determined whether T3r-T3 is less than 0; if it is less than 0 and the IGV opening is not fully opened, an instruction to increase the IGV opening by 1% is output; if the IGV opening is fully opened, an instruction to reduce the fuel flow by 0.1% is output;

[0134] If T3r-T3 is less than the set threshold but not less than 0, the IGV and fuel flow operating parameters remain unchanged;

[0135] If T3r-T3 is greater than the set threshold, the IGV opening reduction instruction is output to increase the combustion chamber outlet temperature (turbine inlet temperature) by reducing the air flow entering the gas turbine, thereby improving the thermal efficiency of the generator set cycle.

[0136] S6: Generate a control command to adjust the turbine inlet temperature toward the turbine inlet temperature limit under safe conditions.

[0137] Further, the generating of the control instruction to adjust the turbine inlet temperature to reach the turbine inlet temperature limit under the safety condition includes:

[0138] After executing the control instruction, the turbine inlet temperature is calculated in real time, and combined with the changes in combustion pressure pulsation and NOx emission data, new IGV and fuel flow control instructions are generated immediately until the turbine inlet temperature T3 satisfies: T3r-T3 is less than the set threshold but greater than 0, that is, to ensure that the turbine inlet temperature T3 tends to the turbine inlet temperature limit T3r under safe conditions, thereby making the gas turbine combustion chamber work in the most efficient state, thereby improving the thermal efficiency of gas turbine power generation.

[0139] In summary, 1. This scheme can calculate the turbine inlet temperature in real time by retrieving the operating parameters such as the combustion chamber inlet pressure P2, turbine exhaust pressure P4, turbine exhaust temperature T4, IGV opening, etc. in the real-time database of the gas turbine generator set, and comprehensively judge the distance between the combustion pressure pulsation, NOx emissions and the combustion chamber outlet temperature and the set value, and adjust the IGV opening and fuel flow rate in real time according to the comparison results to achieve precise adjustment of the gas turbine combustion state. On the premise of ensuring the safe and stable operation of the combustion chamber, the gas turbine turbine inlet temperature is made as close as possible to the protection value set by the control system, thereby improving the cycle thermal efficiency of the gas generator set.

[0140] 2. This solution makes up for the defect that the turbine inlet temperature of the gas turbine cannot be directly measured, and fits the calculation formula of the total pressure loss coefficient of the gas turbine combustion chamber and the specific heat ratio of the combustion chamber outlet gas under different loads, thereby improving the calculation accuracy of the turbine inlet temperature. This solution can reduce the IGV opening of the gas turbine at low load, increase the turbine inlet temperature, and thus improve the thermal efficiency of the gas turbine cycle. At high load, the IGV opening can be increased, and the turbine inlet temperature can be reduced by increasing the air flow entering the gas turbine, thereby preventing turbine blade burning and improving the safety of gas turbine operation.

[0141] 3. This scheme uses the combustion chamber inlet pressure P2 and combines the combustion chamber total pressure loss coefficient to calculate the turbine inlet pressure, and then calculates the turbine inlet temperature T3. The method is simple and feasible, and the implementation efficiency is high.

[0142] The above is a schematic scheme of a method for optimizing the combustion state of a gas turbine in this embodiment. It should be noted that the technical scheme of the system for optimizing the combustion state of a gas turbine and the technical scheme of the above-mentioned method for optimizing the combustion state of a gas turbine belong to the same concept, and the details of the technical scheme of the system for optimizing the combustion state of a gas turbine in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the above-mentioned method for optimizing the combustion state of a gas turbine.

[0143] This embodiment also proposes a gas turbine combustion state optimization control system, including:

[0144] Establishing module, determining module, first judging module, second judging module, third judging module, adjusting module;

[0145] The establishment module is used to obtain the combustion chamber operating parameters of the gas turbine generator set and establish a turbine inlet temperature calculation formula, wherein the operating parameters include but are not limited to the combustion chamber inlet pressure, the turbine exhaust pressure, and the turbine exhaust temperature;

[0146] The determination module is used to determine the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas and calculate the turbine inlet temperature under the current operating conditions;

[0147] The first judgment module is used to obtain combustion pressure pulsation data and compare the combustion pressure pulsation amplitude with a set alarm value to form a first result;

[0148] The second judgment module is used to obtain NOx emission data based on the first result and compare it with the emission standard to form a second result;

[0149] The third judgment module is used to compare the obtained turbine inlet temperature with the set value based on the second result and adjust the IGV opening;

[0150] The adjustment module is used to generate a control instruction to adjust the turbine inlet temperature toward the turbine inlet temperature limit value under a safe condition.

[0151] This embodiment further provides a computing device, which is applicable to the case of optimizing the combustion state of a gas turbine, and includes:

[0152] Memory and processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the method for optimizing the control of the combustion state of a gas turbine as proposed in the above embodiment.

[0153] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for optimizing the control of the combustion state of a gas turbine as proposed in the above embodiment is implemented.

[0154] The storage medium proposed in this embodiment and the method for realizing the optimized control of the combustion state of a gas turbine proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0155] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0156] Example 2

[0157] This embodiment is the second embodiment of the present invention, and verifies the method for optimizing the control of the combustion state of a gas turbine.

[0158] Specifically, it is obtained from the real-time database of a class F gas turbine generator set in a power plant that when the generator set power is 90% load, the combustion chamber inlet pressure P2 is 1.56MPa, the turbine exhaust pressure P4 is 0.105357MPa, and the turbine exhaust temperature T4 is 860K.

[0159] Establish the calculation formula of turbine inlet temperature T3:

[0160]

[0161] Among them, σ c is the total pressure loss coefficient of the gas turbine combustion chamber; n is the specific heat ratio of the gas at the outlet of the gas turbine combustion chamber; η t is the gas turbine efficiency.

[0162] A gas power plant uses a 9FA gas turbine and uses UG modeling software to build a three-dimensional solid model of the gas turbine combustion chamber. Figure 1 , the solid model established by UG was meshed using ANSYS commercial software to build a three-dimensional numerical model of the combustion chamber. Figure 2 .

[0163] Thermoflow power plant heat balance analysis professional software was used to establish a 9FA gas turbine heat balance calculation model. According to the historical operation data of the gas turbine, the inlet atmospheric pressure of the calculation model was set to 1.001 bar, the atmospheric temperature was 21.49 °C, the relative humidity was 79%, and the load was set to 100%. The calculation results are shown in Figure 3The power plant gas turbine operation data shows that the combustion chamber inlet air pressure is 15.5 bar and the temperature is 400 ° C. The pressure and temperature results calculated by Thermoflow are 15.46 bar and 399.8 ° C, respectively, which verifies the accuracy of the established Thermoflow gas turbine heat balance calculation model. In view of the fact that the regular operating load points of the gas turbine of a gas power plant are 50%, 65%, 80%, 95% and 100%, the above loads are taken as typical loads, and the verified Thermoflow gas turbine heat balance calculation model is used to calculate the inlet and outlet boundary parameters of the combustion chamber under the above typical loads. The specific results are shown in Table 1.

[0164] Table 1 Calculation results of gas turbine combustor inlet and outlet boundary parameters

[0165]

[0166]

[0167] According to the combustion chamber inlet and outlet boundary parameters calculated in step 5, the three-dimensional numerical model of the combustion chamber established in step 4 is used to calculate the flow field parameters such as pressure, temperature, and velocity of the gas turbine combustion chamber under typical loads of 50%, 65%, 80%, 95%, and 100%. Some of the results are shown in Figures 4 to 6 , read the total pressure P of the combustion chamber inlet from the numerical calculation results * 2. Total pressure at the combustion chamber outlet P * 3. Use the formula The total pressure loss coefficient σc of the combustion chamber and the specific heat ratio n of the combustion chamber outlet gas under typical loads such as 50%, 65%, 80%, 95% and 100% are calculated respectively. The specific results are shown in Table 2.

[0168] Table 2 Calculation results of total pressure loss coefficient and gas specific heat ratio in combustion chamber

[0169] load Combustion chamber inlet air temperature / ℃ <![CDATA[Air flow rate / kg·s -1 > 50% load 0.038 1.33087 65% load 0.0386 1.31899 80% load 0.0392 1.28342 95% load 0.0398 1.28386 100% load 0.04 1.28393

[0170] Using the curve fitting method, the total pressure loss coefficient σ of the combustion chamber calculated in step 6 is c The calculation formulas of the total pressure loss coefficient σc of the combustion chamber and the specific heat ratio n of the combustion chamber outlet gas are fitted with relative load as the independent variable.

[0171] σ c =0.004w+0.036 0.5≤w≤1.0 (2)

[0172]

[0173] Among them, w is the relative loading of the independent variable.

[0174] Using formula (2) and formula (3), we can calculate the total pressure loss coefficient σc of the combustion chamber under the current working condition to be 0.0396 and the specific heat ratio n of the combustion chamber outlet gas to be 1.283698. Then, we put the operating parameters obtained in step 1 into formula (1), and the turbine efficiency η t Taking 0.96, the calculated turbine inlet temperature T3 is 1523.6K.

[0175] From the real-time database of a power plant's F-class gas turbine generator set, it was obtained that the maximum amplitude of the combustion pressure pulsation at this time was 0.67 kPa, the NOx emission was 15 ppm, the gas turbine turbine inlet temperature limit T3r set by the gas turbine control system was 1620 K, the turbine inlet temperature safety threshold α was set to 10 K, the pressure pulsation alarm value was set to 2.5 kPa, and the local NOx emission standard was less than 25 ppm.

[0176] By comparison, it is found that the maximum amplitude of the combustion pressure pulsation is lower than the pressure pulsation alarm value, and it is further judged that the NOx emission is also lower than the local emission standard. Finally, the calculated turbine inlet temperature T3 is compared with T3r: 1620-1523.6=96.4>α, so an instruction to reduce the IGV opening by 1% is output.

[0177] After the IGV opening is reduced by 1%, the combustion chamber outlet temperature T3 is calculated again to be 1570.8K, the maximum amplitude of the combustion pressure pulsation is 0.65kPa, and the NOx emission is 16ppm. The combustion pressure pulsation is within the safe range, and the NOx emission does not exceed the local emission standard. The turbine inlet temperature increases by 47.2℃, and the gas turbine cycle thermal efficiency increases by about 0.5%. The specific results are shown in Table 3.

[0178] Table 3 Combustion state optimization adjustment results

[0179]

[0180] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0181] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0182] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0183] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0184] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for optimizing the combustion state of a gas turbine, characterized in that: include, Obtaining combustion chamber operating parameters of a gas turbine generator set and establishing a turbine inlet temperature calculation formula, wherein the operating parameters include but are not limited to combustion chamber inlet pressure, turbine exhaust pressure, and turbine exhaust temperature; Determine the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas and calculate the turbine inlet temperature under the current operating conditions; Acquiring combustion pressure pulsation data, and comparing the combustion pressure pulsation amplitude with a set alarm value to form a first result; Based on the first result, obtaining NOx emission data and comparing it with the emission standard to form a second result; Based on the second result, the obtained turbine inlet temperature is compared with the set value and the IGV opening is adjusted; Generate control instructions to adjust the turbine inlet temperature toward the turbine inlet temperature limit under safe conditions.

2. The method for optimizing the combustion state of a gas turbine according to claim 1, wherein: The turbine inlet temperature calculation formula is expressed as: Among them, σ c is the total pressure loss coefficient of the gas turbine combustion chamber; n is the specific heat ratio of the gas at the outlet of the gas turbine combustion chamber; η t is the turbine efficiency of the gas turbine; P2 is the combustion chamber inlet pressure; P4 is the turbine exhaust pressure; T4 is the turbine exhaust temperature; T3 is the turbine inlet temperature.

3. The method for optimizing the combustion state of a gas turbine according to claim 2, wherein: Determining the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas includes: Establish a three-dimensional combustion calculation numerical model of the gas turbine combustor through flow field analysis software such as ANSYS; Establish a Thermoflow gas turbine heat balance calculation model and calculate the inlet and outlet boundary parameters of the combustion chamber of the gas turbine from startup to full load operation, and obtain the boundary parameters of the gas turbine under typical load; the boundary parameters include but are not limited to the mass flow rate of air and fuel at the inlet of the combustion chamber, temperature and the outlet pressure of the combustion chamber; the typical load is selected and determined according to the regular operating load point of the gas turbine power plant; Based on the combustion chamber inlet and outlet boundary parameters, the three-dimensional combustion calculation numerical model is used to calculate and obtain the results of the gas pressure field, temperature field and velocity field in the combustion chamber of the gas turbine under typical load; Based on the results, the total inlet and outlet pressure and outlet gas specific heat ratio of the gas turbine combustion chamber under typical load are analyzed and obtained, and the total pressure loss coefficient of the combustion chamber is calculated and expressed as: Among them, P * 2 is the total pressure at the combustion chamber inlet, P * 3 is the total pressure at the combustion chamber outlet, σ c is the total pressure loss coefficient of the combustion chamber; The curve fitting method is used to fit the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas with relative load as the independent variable, and the calculation formulas of the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas n are respectively obtained, which are expressed as: s c =f(w) n=g(w) Wherein, n is the specific heat ratio of the combustion chamber outlet gas, w is the independent variable relative load, f(w) is the calculation function of the total pressure loss coefficient of the combustion chamber obtained by fitting, and g(w) is the calculation function of the specific heat ratio of the combustion chamber outlet gas obtained by fitting.

4. The method for optimizing the control of the combustion state of a gas turbine according to claim 3, characterized in that: The step of obtaining the combustion pressure pulsation data and comparing the combustion pressure pulsation amplitude with the set alarm value to form a first result includes: Obtain multiple measurements of combustion pressure pulsation P from the operating data of the gas turbine generator set i , where i = 1, 2, ... m, m is the number of measurements; Calculate the average of the pressure pulsation measurements, expressed as: in, is the average pressure, P i is the i-th pressure pulsation measurement value; The combustion pressure pulsation amplitude is calculated and expressed as: Among them, ΔP actual is the combustion pressure pulsation amplitude actually calculated, Pi is the i-th pressure pulsation measurement value, is the average pressure, m is the number of measurements, and α is the correction coefficient; Calculate the standard deviation of the combustion pressure pulsation, expressed as: Among them, σ P is the standard deviation of combustion pressure pulsation; P i is the i-th pressure pulsation measurement value; The combustion pressure pulsation amplitude is compared with the alarm value through a comprehensive judgment formula, which is expressed as: Among them, δ is the judgment result, ΔP actual is the actual calculated combustion pressure pulsation amplitude, ΔP threshold is the set alarm value, σ P is the standard deviation of combustion pressure pulsation; The forming of the first result includes that when δ>1, it indicates that the combustion pressure pulsation amplitude exceeds the alarm value, and an instruction to increase the on-duty fuel flow by 0.1% is issued; when δ≤1, it indicates that the combustion pressure pulsation amplitude does not exceed the alarm value, and the fuel flow does not need to be adjusted.

5. The method for optimizing the control of the combustion state of a gas turbine according to claim 4, characterized in that: The first result includes: When the combustion pressure pulsation amplitude does not exceed the alarm value set in the engine control system, obtain NOx emission data and compare it with the emission standards; The obtaining of NOx emission data and comparing with emission standards includes: Obtain relevant parameters from the operating data of the gas turbine generator set; The NOx emissions are compared with the local emission standards through a comprehensive comparison formula, expressed as: Among them, NOx actual is the NOx emission, σ is the judgment result, NOx actual is the actual measured NOx emission, NOx standard for local emission standards; The forming of the second result includes that when σ>0, it indicates that NOx emissions exceed the local emission standard, and an instruction to reduce the fuel flow by 0.1% is issued; when σ≤0, it indicates that NOx emissions do not exceed the local emission standard, and the fuel flow does not need to be adjusted.

6. The method for optimizing the control of the combustion state of a gas turbine according to claim 5, characterized in that: The second result includes: When NOx emissions do not exceed the local emission standards, the calculated turbine inlet temperature T3 is compared with the set value T3r in the gas turbine control system; The adjusting of the IGV opening comprises: If T3r-T3 is less than the set threshold, it is further determined whether T3r-T3 is less than 0; if it is less than 0 and the IGV opening is not fully opened, an instruction to increase the IGV opening by 1% is output; if the IGV opening is fully opened, an instruction to reduce the fuel flow by 0.1% is output; If T3r-T3 is less than the set threshold but not less than 0, the IGV and fuel flow operating parameters remain unchanged; If T3r-T3 is greater than the set threshold, an instruction to reduce the IGV opening is output to increase the combustion chamber outlet temperature by reducing the air flow entering the gas turbine.

7. The method for optimizing the control of the combustion state of a gas turbine according to claim 6, characterized in that: The generating of control instructions to adjust the turbine inlet temperature to reach the turbine inlet temperature limit under safety conditions includes: After executing the control instruction, the turbine inlet temperature is calculated in real time, and combined with the changes in combustion pressure pulsation and NOx emission data, new IGV and fuel flow control instructions are generated immediately until the turbine inlet temperature T3 satisfies: T3r-T3 is less than the set threshold but greater than 0, that is, to ensure that the turbine inlet temperature T3 tends to the turbine inlet temperature limit T3r under safe conditions.

8. A system using the gas turbine combustion state optimization control method according to any one of claims 1 to 7, characterized in that: It includes an establishment module, a determination module, a first judgment module, a second judgment module, a third judgment module, and an adjustment module; The establishment module is used to obtain the combustion chamber operating parameters of the gas turbine generator set and establish a turbine inlet temperature calculation formula, wherein the operating parameters include but are not limited to the combustion chamber inlet pressure, the turbine exhaust pressure, and the turbine exhaust temperature; The determination module is used to determine the total pressure loss coefficient of the combustion chamber and the specific heat ratio of the combustion chamber outlet gas and calculate the turbine inlet temperature under the current operating conditions; The first judgment module is used to obtain combustion pressure pulsation data and compare the combustion pressure pulsation amplitude with a set alarm value to form a first result; The second judgment module is used to obtain NOx emission data based on the first result and compare it with the emission standard to form a second result; The third judgment module is used to compare the obtained turbine inlet temperature with the set value based on the second result and adjust the IGV opening; The adjustment module is used to generate a control instruction to adjust the turbine inlet temperature toward the turbine inlet temperature limit value under a safe condition.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the gas turbine combustion state optimization control method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the gas turbine combustion state optimization control method according to any one of claims 1 to 7 are implemented.

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