A method and apparatus for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process.

Abstract

This invention provides a method and apparatus for solving key thermodynamic coefficients of a boiler during secondary frequency regulation. Based on the thermodynamic parameters at the beginning and end of the boiler, the thermodynamic state variables of the entire counter-current heat exchanger model are calculated. Inputs include the main steam valve opening value, coal feed rate, air supply rate, feedwater flow rate, feedwater temperature, and feedwater pressure. Initial iterative values ​​for the key coefficients of the current heat exchange system are set. The initial and end thermodynamic parameter values ​​are compared with the iterative results, and iterative corrections are performed. After iterative convergence, the correlation coefficients of the boiler's thermodynamic characteristics during secondary frequency regulation are obtained. This invention solves the problem that existing methods for secondary frequency regulation fail to reflect multiple operating conditions by ensuring that key thermodynamic characteristic parameters of boilers under supercritical operating conditions are adequately reflected.

Description

Technical Field

[0001] This invention relates to the field of thermal system analysis technology, and in particular to a method and apparatus for solving key thermal coefficients of a boiler in a secondary frequency regulation process. Background Technology

[0002] Secondary frequency regulation refers to the process by which generating units adjust their output in accordance with instructions from the dispatch center to maintain a power balance between generation and consumption, in order to achieve error-free regulation of the power grid frequency. This process can be completed manually according to instructions from the central dispatch center or operators, or automatically using Automatic Generation Control (AGC). For thermal power units, secondary frequency regulation mainly involves adjusting their output to meet the requirements of AGC power commands after receiving them. In traditional power grids, due to the dominant position of thermal power units, secondary frequency regulation commands can generally be met. However, with the integration of a large number of renewable energy sources, the frequency problem of the power grid has become increasingly prominent. While the capacity share of thermal power units is decreasing, the frequency gap that the power grid needs to fill is also increasing. This means that thermal power units need to fully utilize their secondary frequency regulation potential. Therefore, accurately understanding the true secondary frequency regulation capability of thermal power units is of great significance for ensuring system frequency security and secondary frequency regulation power allocation.

[0003] However, existing boiler models only input fuel commands and output main steam pressure. Compared to the actual heat exchange process of a boiler, these input and output parameters are limited, lacking interfaces for commands such as feedwater and air supply. Therefore, a boiler counter-current heat exchanger model is needed as an improved secondary frequency regulation model. This model can input multiple commands, including coal feeding and air supply, and output the changes in main steam pressure and flow rate. Using a boiler counter-current heat exchanger model will help reflect the frequency regulation process and capability of thermal power units more accurately.

[0004] Currently, to fully utilize new energy sources, an increasing number of thermal power units are undergoing flexibility retrofits, meaning that more and more thermal power units may be operating under deep peak-shaving conditions. Due to the significant expansion of the operating range, boiler models using fixed or design parameters may not be able to reflect multi-condition environments. Therefore, to obtain key parameters of the boiler heat exchanger model that conforms to the current state, it is necessary to identify the key thermodynamic coefficients of the thermal power unit under the current state based on measurement results of the actual boiler operating conditions. This will avoid errors between design parameters and actual parameters and help to more accurately reflect the secondary frequency regulation process of the thermal power unit. Summary of the Invention

[0005] This invention provides a method and apparatus for solving the key thermodynamic coefficients of a boiler during a secondary frequency regulation process, in order to solve the problem that the key thermodynamic characteristic parameters of a boiler under supercritical operating conditions in the existing secondary frequency regulation process cannot reflect multiple operating environments.

[0006] This invention provides a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, comprising:

[0007] Based on the data collected by the distributed control system, the current boiler operating conditions are obtained;

[0008] Set the initial values ​​for the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0009] If the boiler counter-current heat exchanger model number to be calculated for the next segment has not reached the maximum number of segments of the boiler model, then the thermodynamic state of the boiler counter-current heat exchanger for the next segment is calculated.

[0010] Based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model, the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium are obtained through physical property conversion.

[0011] Calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and calculate the qualitative temperature and qualitative pressure within the heat exchange unit;

[0012] Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this section of the boiler, the specific heat capacity and density of the steam and water working fluid of this section of the boiler model are calculated by the physical property equation.

[0013] After calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model, the deviations between the calculated results and the actual conditions are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

[0014] Based on the final obtained flue gas specific heat capacity and the full thermodynamic state of the boiler model, the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model are calculated.

[0015] Based on the input operating conditions, the key thermodynamic parameters of the thermal power unit under the current state are obtained by identification.

[0016] According to the present invention, a method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process, wherein obtaining the current boiler operating conditions based on data collected by the distributed control system specifically includes:

[0017] The current boiler operation regulation includes coal feed rate, air supply rate, furnace temperature, boiler flue gas outlet temperature, steam-water separator outlet temperature and pressure of working fluid, main steam temperature, main steam flow rate, main steam pressure, superheater outlet wall temperature, and main steam valve opening, and the number of segments of the boiler counter-current heat exchanger model is given.

[0018] According to the method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process provided by the present invention, when it is determined that the boiler countercurrent heat exchanger model number to be calculated in the next segment has reached the maximum number of segments of the boiler model, the deviations between the calculated results and the actual conditions are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure and the metal wall temperature at the beginning of the boiler model.

[0019] According to the present invention, a method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process, after calculating the specific heat capacity and density of the steam-water working fluid of the boiler model based on the qualitative temperature and qualitative pressure of the counter-current heat exchanger model of this section of the boiler through the property equation, further includes:

[0020] The specific heat capacity and density of the steam-water working fluid in this section of the boiler countercurrent heat exchanger model are compared with the initial values ​​of the specific heat capacity and density of the steam-water working fluid, respectively, to determine whether convergence has occurred.

[0021] If the deviation is greater than the first set threshold based on the comparison results, then the convergence has not occurred, and the specific heat capacity and density values ​​are updated.

[0022] If the deviation is less than or equal to the first set threshold, then convergence is achieved. Next, it is determined whether the boiler countercurrent heat exchanger model number to be calculated in the next segment has reached the maximum number of segments of the boiler model.

[0023] According to the present invention, a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process includes, after calculating the thermodynamic state variables of the entire section of the boiler counter-current heat exchanger model, comparing the deviations between the calculated results and the actual conditions for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model. This includes:

[0024] Compare the deviations between the calculated results and the actual conditions for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model; and generate comparison results.

[0025] Based on the comparison results, if the deviation is greater than the second set threshold, then the convergence has not occurred, and the heat transfer coefficient, drag coefficient, and flue gas specific heat capacity are updated.

[0026] Based on the comparison results, if the deviation is less than or equal to the second set threshold, then convergence is achieved, and the heat released by the unit combustion of the medium and the valve flow coefficient are calculated.

[0027] According to the present invention, a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process is provided. The step of identifying key thermodynamic parameters of a thermal power unit under the current state based on input operating conditions includes:

[0028] Based on the input operating conditions, the system identification process yields the key thermodynamic parameters of the thermal power unit under the current conditions, including the heat transfer coefficient between flue gas and metal walls, the heat transfer coefficient between steam-water working fluid and metal walls, the resistance coefficient of steam-water working fluid flow, the specific heat capacity of flue gas, the heat released per unit of coal combustion, the valve flow coefficient, and the full-section thermodynamic state of the boiler countercurrent heat exchanger model.

[0029] The present invention also provides a device for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, comprising:

[0030] The data acquisition module is used to obtain the current boiler operating conditions based on data collected from the distributed control system.

[0031] The first initial value determination module is used to set the initial values ​​of the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0032] The model number judgment module is used to determine the thermodynamic state of the next section of the boiler countercurrent heat exchanger if the model number of the next section to be calculated has not reached the maximum number of segments of the boiler model.

[0033] The second initial value determination module is used to obtain the initial values ​​of specific heat capacity and density of the current section of steam and water working medium by converting the temperature and pressure of the steam and water working medium at the end of the previous section of the boiler countercurrent heat exchanger model through physical property conversion.

[0034] The quantification temperature and pressure calculation module is used to calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and to calculate the quantification temperature and pressure within the heat exchange unit.

[0035] The steam-water specific heat and density calculation module is used to calculate the specific heat capacity and density of the steam-water working fluid in this section of the boiler model based on the qualitative temperature and qualitative pressure of the boiler counter-current heat exchanger model in this section, through the physical property equation.

[0036] The deviation comparison module is used to compare the deviations between the calculated results and the actual conditions of the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model after calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model.

[0037] The heat and flow calculation module is used to calculate the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model based on the final obtained flue gas specific heat capacity and the thermodynamic state of the entire boiler model.

[0038] The key thermodynamic parameter determination module is used to identify the key thermodynamic parameters of the thermal power unit under the current state based on the input operating conditions.

[0039] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement a method for solving the key thermodynamic coefficients of a boiler in any of the above-described secondary frequency regulation processes.

[0040] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for solving the key thermodynamic coefficients of a boiler in the secondary frequency modulation process as described above.

[0041] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements a method for solving the key thermodynamic coefficients of a boiler in any of the above-described secondary frequency regulation processes.

[0042] This invention provides a method and apparatus for solving key thermodynamic coefficients of a boiler during a secondary frequency regulation process. Based on the thermodynamic parameters at the beginning and end of the boiler, the thermodynamic state variables of the entire section of the boiler counter-current heat exchanger model are calculated. Inputs include the main steam valve opening value, coal feed rate, air supply rate, feedwater flow rate, feedwater temperature, and feedwater pressure. Initial iterative values ​​for the key coefficients of the current heat exchange system are set. The initial and end thermodynamic parameter values ​​are compared with the iterative results, and iterative corrections are performed. After iterative convergence, the correlation coefficients of the boiler's thermodynamic characteristics during the secondary frequency regulation process are obtained. This invention can accurately describe the dynamic response characteristics of key thermodynamic parameters of the boiler under supercritical operating conditions during secondary frequency regulation, thus providing key thermodynamic parameters of thermal power units, such as heat transfer coefficients, that conform to the current operating conditions, without relying on design parameters. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is one of the flowcharts illustrating a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process provided by the present invention.

[0045] Figure 2 This is the second flowchart illustrating a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process provided by the present invention.

[0046] Figure 3 This is the third flowchart illustrating a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process provided by the present invention.

[0047] Figure 4This is a schematic diagram of the module connection of a device for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process provided by the present invention.

[0048] Figure 5 This is a flowchart illustrating the architecture of a device for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, provided by the present invention.

[0049] Figure 6 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0050] Figure label:

[0051] 110: Data acquisition module; 120: First initial value determination module; 130: Model number determination module; 140: Second initial value determination module; 150: Shaping temperature and pressure calculation module; 160: Steam-water specific heat and density calculation module; 170: Deviation comparison module; 180: Heat and flow rate calculation module; 190: Key thermodynamic parameter determination module;

[0052] 610: Processor; 620: Communication interface; 630: Memory; 640: Communication bus. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0054] The following is combined with Figures 1-3 The present invention describes a method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, comprising:

[0055] S100. Obtain the current boiler operating conditions based on the data collected by the distributed control system;

[0056] S200, set the initial values ​​of the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0057] If S300 determines that the boiler counter-current heat exchanger model number to be calculated in the next segment has not reached the maximum number of segments of the boiler model, then it calculates the thermodynamic state of the boiler counter-current heat exchanger in the next segment.

[0058] S400. Based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model, the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium are obtained through physical property conversion.

[0059] S500: Calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and calculate the qualitative temperature and qualitative pressure within the heat exchange unit.

[0060] S600. Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this section of the boiler, calculate the specific heat capacity and density of the steam-water working fluid of this section of the boiler model through the physical property equation.

[0061] S700. After calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model, compare the deviations between the calculated results and the actual conditions for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and metal wall temperature at the end of the boiler model and the beginning.

[0062] S800. Based on the final obtained flue gas specific heat capacity and the thermodynamic state of the entire boiler model, calculate the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model.

[0063] S900: Based on the input operating conditions, the key thermodynamic parameters of the thermal power unit under the current state are obtained by identification.

[0064] In this invention, a one-dimensional counter-current heat exchanger model can more accurately describe the boiler dynamics during the secondary frequency regulation process of thermal power units, and also provides more input interfaces. Many key thermodynamic coefficients in the heat exchanger model can be identified and calculated based on the real-time operating conditions of the boiler, without the need for design parameters.

[0065] By using measurement data of the boiler's current operating conditions and through iterative solutions, a thermodynamic coefficient that conforms to the current operating conditions can be obtained. Compared with using fixed parameters, the thermodynamic coefficient obtained by this method can more accurately reflect various operating conditions, especially under deep peak-shaving conditions of thermal power units.

[0066] Based on data collected by the distributed control system, the current boiler operating conditions are obtained, specifically including:

[0067] The current boiler operation regulation includes coal feed rate, air supply rate, furnace temperature, boiler flue gas outlet temperature, steam-water separator outlet temperature and pressure of working fluid, main steam temperature, main steam flow rate, main steam pressure, superheater outlet wall temperature, and main steam valve opening, and the number of segments of the boiler counter-current heat exchanger model is given.

[0068] Measurement data can be taken from a single time section or as an average over a period of time. The number of measurement points selected can increase or decrease the identified thermal coefficient. The accuracy of the identification results depends primarily on the accuracy of the measurement data and the selection of measurement points.

[0069] For the boiler counter-current heat exchanger model, the key thermodynamic coefficients during secondary frequency regulation mainly include: the heat transfer coefficient between flue gas and the metal wall, the heat transfer coefficient between the steam-water working fluid and the metal wall, the resistance coefficient of the steam-water working fluid flow, the specific heat capacity of the flue gas, the heat released per unit of coal combustion, and the valve flow coefficient. Simultaneously, the identification results can also provide the full-section thermodynamic state of the boiler's one-dimensional segmented heat exchanger model.

[0070] In this invention, the heat transfer coefficient k between the flue gas and the metal wall is set. h A h The heat transfer coefficient k between the steam-water working fluid and the metal wall c A c The resistance coefficient ζ of the steam-water working fluid cσ The specific heat capacity of flue gas, c ph The initial value can be calculated based on the boiler's design parameters, or it can be given as an approximate order of magnitude based on the material.

[0071] If the boiler countercurrent heat exchanger model number to be calculated in the next segment reaches the maximum number of segments of the boiler model, then compare the deviations between the calculated results and the actual conditions for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

[0072] In this invention, the boiler model number to be calculated next is determined. If the number has reached the maximum number of segments of the boiler model, the iteration results are compared with the actual data. If the number has not reached the maximum number of segments of the boiler model, the thermodynamic state of the next boiler model is calculated from the parameters of the previous boiler model.

[0073] Set the specific heat capacity c of the working fluid in this section. pc(j) and density ρ c(j) The initial value can be obtained by converting the temperature and pressure of the steam and water working fluid at the end of the previous section of the boiler model through physical property calculation.

[0074] Calculate the steam-water working fluid pressure P at the end of this section of the boiler model using the following equation. c(j+1) ;

[0075]

[0076] Among them, P c(j) The steam-water working fluid pressure at the beginning of this section of the boiler model is equal to the steam-water working fluid pressure at the end of the previous section of the boiler model; P c(j+1) The pressure of the steam-water working fluid at the end of this section of the boiler model; ζ cσ D represents the resistance coefficient for the current flow of the steam-water working fluid. c The flow rate of the working fluid (water-steam mixture) can be taken as the main steam flow rate; ρ c(j) This is the currently set density of the working fluid in this section of the steam-water mixture.

[0077] Calculate the metal wall temperature T of this boiler model using the following equation. w(j) Terminal flue gas temperature T h(j+1) and the end-of-pipe working fluid temperature T c(j+1) ;

[0078]

[0079] Among them, R c(j) The thermal resistance between the steam-water working fluid and the metal wall in this section of the boiler model; k c A c G represents the currently set heat transfer coefficient between the steam-water working fluid and the metal wall. c(j) R represents the heat capacity flow rate of the steam-water working fluid in this boiler model, numerically expressed as the product of the steam-water working fluid flow rate and its specific heat capacity; h The thermal resistance between the flue gas and the metal wall of the boiler model; k h A h G represents the currently set heat transfer coefficient between the flue gas and the metal wall. h T represents the heat capacity flow rate of the flue gas in the boiler model, numerically expressed as the product of the flue gas flow rate and the specific heat capacity; w(j) T represents the temperature of the metal wall in this section. h(j) T represents the flue gas temperature at the beginning of this section. c(j+1) T represents the temperature of the steam-water working fluid at the end of this section. c(j0 T represents the temperature of the steam-water working fluid at the beginning of this section. h(j+1) This is the flue gas temperature at the end of this section.

[0080] The characteristic temperature of the steam-water working fluid in this section of the boiler model is calculated using the following equation. Qualitative pressure

[0081]

[0082] in, This is the qualitative temperature of the working fluid in this section; T c(j) T represents the initial temperature of the steam-water working fluid in this section of the boiler model. c(j+1) This refers to the temperature of the steam-water working fluid at the end of this section of the boiler model; P is the qualitative pressure of the working fluid in this section; c(j+1) This represents the steam and water working fluid pressure at the end of this section of the boiler model.

[0083] Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this boiler section, after calculating the specific heat capacity and density of the steam-water working fluid of this boiler section through the property equation, the following is also included:

[0084] S101. Compare the specific heat capacity and density of the steam-water working fluid in this section of the boiler countercurrent heat exchanger model with the initial values ​​of the specific heat capacity and density of the steam-water working fluid, respectively, and determine whether convergence has occurred.

[0085] S102. If the deviation is greater than the first set threshold based on the comparison results, then the convergence has not been achieved, and the specific heat capacity and density values ​​are updated.

[0086] S103. If the deviation is less than or equal to the first set threshold, then convergence is achieved. Then, determine whether the boiler countercurrent heat exchanger model number to be calculated in the next segment has reached the maximum number of segments of the boiler model.

[0087] After calculating the thermodynamic state quantities of the entire section of the boiler counter-current heat exchanger model, the deviations between the calculated results and the actual conditions are compared for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model, and the metal wall temperature at the beginning. These deviations include:

[0088] S201. Compare the deviations between the calculated results and the actual conditions of the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model, and generate comparison results.

[0089] S202. Based on the comparison results, if the deviation is greater than the second set threshold, then the convergence has not occurred, and the heat transfer coefficient, drag coefficient, and flue gas specific heat capacity are updated.

[0090] S203. Based on the comparison results, if the deviation is less than or equal to the second set threshold, then convergence is achieved, and the heat released by the unit combustion of the medium and the valve flow coefficient are calculated.

[0091] In this invention, based on the final obtained flue gas specific heat capacity and the thermodynamic state of the entire boiler model, the heat Qη released by the unit coal combustion of the boiler model and the valve flow coefficient kv are calculated according to the following equations.

[0092]

[0093] Where B is the coal feed rate; D k D is the air supply volume. h c is the flue gas flow rate; k T is the specific heat capacity of air. k c represents air temperature, which can be taken as ambient temperature; h T represents the specific heat capacity of the final flue gas. h(1) The initial flue gas temperature of the boiler model can be taken as the furnace temperature; D c k is the flow rate of the carbonated working fluid. v Valve flow coefficient; cv is the main steam valve opening; P (1) The initial steam-water working fluid pressure of the boiler model.

[0094] The process of identifying key thermodynamic parameters of the thermal power unit under the current state based on the input operating conditions includes:

[0095] Based on the input operating conditions, the system identification process yields the key thermodynamic parameters of the thermal power unit under the current conditions, including the heat transfer coefficient between flue gas and metal walls, the heat transfer coefficient between steam-water working fluid and metal walls, the resistance coefficient of steam-water working fluid flow, the specific heat capacity of flue gas, the heat released per unit of coal combustion, the valve flow coefficient, and the full-section thermodynamic state of the boiler countercurrent heat exchanger model.

[0096] This invention provides a method for solving key thermodynamic coefficients of a boiler during a secondary frequency regulation process. Based on the boiler's initial and final thermodynamic parameters, the thermodynamic state variables of the entire counter-current heat exchanger model are calculated. Inputs include the main steam valve opening, coal feed rate, air supply rate, feedwater flow rate, feedwater temperature, and feedwater pressure. Initial iterative values ​​for the key coefficients of the current heat exchange system are set. The initial and final thermodynamic parameter values ​​are compared with the iterative results, and iterative corrections are performed. After iterative convergence, the correlation coefficients of the boiler's thermodynamic characteristics during the secondary frequency regulation process are obtained. This invention can accurately describe the dynamic response characteristics of key thermodynamic parameters of a boiler under supercritical operating conditions during secondary frequency regulation, thus providing key thermodynamic parameters of thermal power units, such as heat transfer coefficients, that conform to the current operating conditions, without relying on design parameters.

[0097] refer to Figure 4 and Figure 5 The present invention also discloses a device for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, comprising:

[0098] Data acquisition module 110 is used to obtain the current boiler operating conditions based on data collected by the distributed control system.

[0099] The first initial value determination module 120 is used to set the initial values ​​of the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0100] The model number judgment module 130 is used to determine the thermodynamic state of the next section of the boiler counterflow heat exchanger if the model number of the next section to be calculated has not reached the maximum number of segments of the boiler model.

[0101] The second initial value determination module 140 is used to obtain the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium by physical property conversion based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model.

[0102] The 150-type temperature and pressure calculation module is used to calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler countercurrent heat exchanger model, and to calculate the qualitative temperature and pressure within the heat exchange unit.

[0103] The steam-water specific heat and density calculation module 160 is used to calculate the specific heat capacity and density of the steam-water working fluid of the boiler model based on the qualitative temperature and qualitative pressure of the counter-current heat exchanger model of this section of the boiler through the physical property equation.

[0104] The deviation comparison module 170 is used to compare the deviations between the calculated results and the actual conditions of the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure and the metal wall temperature at the beginning of the boiler model after calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model.

[0105] The heat and flow calculation module 180 is used to calculate the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model based on the final obtained flue gas specific heat capacity and the thermodynamic state of the entire boiler model.

[0106] The key thermodynamic parameter determination module 190 is used to identify the key thermodynamic parameters of the thermal power unit under the current state based on the input operating conditions.

[0107] The data acquisition module adjusts the following parameters based on the current boiler operation status: coal feed rate, air supply rate, furnace temperature, boiler flue gas outlet temperature, steam-water separator outlet temperature and pressure of working fluid, main steam temperature, main steam flow rate, main steam pressure, superheater outlet wall temperature, and main steam valve opening. It also specifies the number of segments in the boiler counter-current heat exchanger model.

[0108] The model number judgment module determines whether the boiler countercurrent heat exchanger model number to be calculated in the next segment has reached the maximum number of segments of the boiler model. Then, it compares the deviations between the calculated results and the actual conditions of the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

[0109] The deviation comparison module compares the deviations between the calculated results and the actual conditions of the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model, and generates comparison results.

[0110] Based on the comparison results, if the deviation is greater than the second set threshold, then the convergence has not occurred, and the heat transfer coefficient, drag coefficient, and flue gas specific heat capacity are updated.

[0111] Based on the comparison results, if the deviation is less than or equal to the second set threshold, then convergence is achieved, and the heat released by the unit combustion of the medium and the valve flow coefficient are calculated.

[0112] The key thermodynamic parameter determination module, based on the input operating conditions, obtains the key thermodynamic parameters of the thermal power unit under the current state by completing system identification. These parameters include the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, the specific heat capacity of flue gas, the heat released per unit of coal combustion, the valve flow coefficient, and the full-section thermodynamic state of the boiler countercurrent heat exchanger model.

[0113] This invention provides a device for solving key thermodynamic coefficients of a boiler during a secondary frequency regulation process. Based on the boiler's initial and final thermodynamic parameters, it calculates the thermodynamic state variables of the entire counter-current heat exchanger model. Inputs include the main steam valve opening, coal feed rate, air supply rate, feedwater flow rate, feedwater temperature, and feedwater pressure. Initial iterative values ​​for the key coefficients of the current heat exchange system are set. The initial and final thermodynamic parameter values ​​are compared with the iterative results, and iterative corrections are performed. After iterative convergence, the correlation coefficients of the boiler's thermodynamic characteristics during the secondary frequency regulation process are obtained. This invention can accurately describe the dynamic response characteristics of key thermodynamic parameters of a boiler under supercritical operating conditions during secondary frequency regulation, thus providing key thermodynamic parameters of thermal power units, such as heat transfer coefficients, that conform to the current operating conditions, without relying on design parameters.

[0114] Figure 6 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 6 As shown, the electronic device may include a processor 610, a communication interface 620, a memory 630, and a communication bus 640. The processor 610, communication interface 620, and memory 630 communicate with each other via the communication bus 640. The processor 610 can call logical instructions from the memory 630 to execute a method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process. This method includes: obtaining the current boiler operating conditions based on data collected by the distributed control system.

[0115] Set the initial values ​​for the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0116] If the boiler counter-current heat exchanger model number to be calculated for the next segment has not reached the maximum number of segments of the boiler model, then the thermodynamic state of the boiler counter-current heat exchanger for the next segment is calculated.

[0117] Based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model, the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium are obtained through physical property conversion.

[0118] Calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and calculate the qualitative temperature and qualitative pressure within the heat exchange unit;

[0119] Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this section of the boiler, the specific heat capacity and density of the steam and water working fluid of this section of the boiler model are calculated by the physical property equation.

[0120] After calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model, the deviations between the calculated results and the actual conditions are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

[0121] Based on the final obtained flue gas specific heat capacity and the full thermodynamic state of the boiler model, the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model are calculated.

[0122] Based on the input operating conditions, the key thermodynamic parameters of the thermal power unit under the current state are obtained by identification.

[0123] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0124] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute a method for solving the key thermodynamic coefficients of a boiler in a secondary frequency modulation process provided by the above methods. The method includes: obtaining the current boiler operating conditions based on data collected by the distributed control system.

[0125] Set the initial values ​​for the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0126] If the boiler counter-current heat exchanger model number to be calculated for the next segment has not reached the maximum number of segments of the boiler model, then the thermodynamic state of the boiler counter-current heat exchanger for the next segment is calculated.

[0127] Based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model, the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium are obtained through physical property conversion.

[0128] Calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and calculate the qualitative temperature and qualitative pressure within the heat exchange unit;

[0129] Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this section of the boiler, the specific heat capacity and density of the steam and water working fluid of this section of the boiler model are calculated by the physical property equation.

[0130] After calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model, the deviations between the calculated results and the actual conditions are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

[0131] Based on the final obtained flue gas specific heat capacity and the full thermodynamic state of the boiler model, the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model are calculated.

[0132] Based on the input operating conditions, the key thermodynamic parameters of the thermal power unit under the current state are obtained by identification.

[0133] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a method for solving the key thermodynamic coefficients of a boiler in a secondary frequency modulation process provided by the methods described above, the method comprising: obtaining the boiler operating conditions in the current state based on data collected by a distributed control system;

[0134] Set the initial values ​​for the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas.

[0135] If the boiler counter-current heat exchanger model number to be calculated for the next segment has not reached the maximum number of segments of the boiler model, then the thermodynamic state of the boiler counter-current heat exchanger for the next segment is calculated.

[0136] Based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model, the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium are obtained through physical property conversion.

[0137] Calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and calculate the qualitative temperature and qualitative pressure within the heat exchange unit;

[0138] Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this section of the boiler, the specific heat capacity and density of the steam and water working fluid of this section of the boiler model are calculated by the physical property equation.

[0139] After calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model, the deviations between the calculated results and the actual conditions are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

[0140] Based on the final obtained flue gas specific heat capacity and the full thermodynamic state of the boiler model, the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model are calculated.

[0141] Based on the input operating conditions, the key thermodynamic parameters of the thermal power unit under the current state are obtained by identification.

[0142] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0143] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, characterized in that, include: Based on the data collected by the distributed control system, the current boiler operating conditions are obtained; Set the initial values ​​for the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas. If the boiler counter-current heat exchanger model number to be calculated for the next segment has not reached the maximum number of segments of the boiler model, then the thermodynamic state of the boiler counter-current heat exchanger for the next segment is calculated. Based on the temperature and pressure of the steam-water working medium at the end of the previous section of the boiler countercurrent heat exchanger model, the initial values ​​of the specific heat capacity and density of the current section of the steam-water working medium are obtained through physical property conversion. Calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and calculate the qualitative temperature and qualitative pressure within the heat exchange unit; Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this section of the boiler, the specific heat capacity and density of the steam and water working fluid of this section of the boiler model are calculated by the physical property equation. After calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model, the deviations between the calculated results and the actual conditions are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning. Based on the final obtained flue gas specific heat capacity and the full thermodynamic state of the boiler model, the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model are calculated. Based on the input operating conditions, the key thermodynamic parameters of the thermal power unit under the current state are obtained by identification.

2. The method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process according to claim 1, characterized in that, The process of obtaining the current boiler operating conditions based on data collected by the distributed control system specifically includes: The current boiler operation regulation includes coal feed rate, air supply rate, furnace temperature, boiler flue gas outlet temperature, steam-water separator outlet temperature and pressure of working fluid, main steam temperature, main steam flow rate, main steam pressure, superheater outlet wall temperature, and main steam valve opening, and the number of segments of the boiler counter-current heat exchanger model is given.

3. The method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process according to claim 1, characterized in that, If the boiler countercurrent heat exchanger model number to be calculated in the next segment reaches the maximum number of segments of the boiler model, then the deviations between the calculated results and the actual state are compared between the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model and the metal wall temperature at the beginning.

4. The method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process according to claim 1, characterized in that, Based on the qualitative temperature and pressure of the counter-current heat exchanger model of this boiler section, and after calculating the specific heat capacity and density of the steam-water working fluid of this boiler section model through the property equation, the method further includes: The specific heat capacity and density of the steam-water working fluid in this section of the boiler countercurrent heat exchanger model are compared with the initial values ​​of the specific heat capacity and density of the steam-water working fluid, respectively, to determine whether convergence has occurred. If the deviation is greater than the first set threshold based on the comparison results, then the convergence has not occurred, and the specific heat capacity and density values ​​are updated. If the deviation is less than or equal to the first set threshold, then convergence is achieved. Next, it is determined whether the boiler countercurrent heat exchanger model number to be calculated in the next segment has reached the maximum number of segments of the boiler model.

5. The method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process according to claim 1, characterized in that, After calculating the thermodynamic state quantities of the entire section of the boiler counter-current heat exchanger model, the deviations between the calculated results and the actual conditions are compared for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure at the end of the boiler model, and the metal wall temperature at the beginning. These deviations include: Compare the deviations between the calculated results and the actual conditions for the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model; and generate comparison results. Based on the comparison results, if the deviation is greater than the second set threshold, then the convergence has not occurred, and the heat transfer coefficient, drag coefficient, and flue gas specific heat capacity are updated. Based on the comparison results, if the deviation is less than or equal to the second set threshold, then convergence is achieved, and the heat released by the unit combustion of the medium and the valve flow coefficient are calculated.

6. The method for solving the key thermodynamic coefficients of a boiler in a secondary frequency regulation process according to claim 1, characterized in that, The process of identifying key thermodynamic parameters of the thermal power unit under the current state based on the input operating conditions includes: Based on the input operating conditions, the system identification process yields the key thermodynamic parameters of the thermal power unit under the current conditions, including the heat transfer coefficient between flue gas and metal walls, the heat transfer coefficient between steam-water working fluid and metal walls, the resistance coefficient of steam-water working fluid flow, the specific heat capacity of flue gas, the heat released per unit of coal combustion, the valve flow coefficient, and the full-section thermodynamic state of the boiler countercurrent heat exchanger model.

7. A device for solving key thermodynamic coefficients of a boiler in a secondary frequency regulation process, characterized in that, include: The data acquisition module is used to obtain the current boiler operating conditions based on data collected from the distributed control system. The first initial value determination module is used to set the initial values ​​of the heat transfer coefficient between flue gas and metal wall, the heat transfer coefficient between steam-water working fluid and metal wall, the resistance coefficient of steam-water working fluid flow, and the specific heat capacity of flue gas. The model number judgment module is used to determine the thermodynamic state of the next section of the boiler countercurrent heat exchanger if the model number of the next section to be calculated has not reached the maximum number of segments of the boiler model. The second initial value determination module is used to obtain the initial values ​​of specific heat capacity and density of the current section of steam and water working medium by converting the temperature and pressure of the steam and water working medium at the end of the previous section of the boiler countercurrent heat exchanger model through physical property conversion. The quantification temperature and pressure calculation module is used to calculate the steam-water working fluid pressure and various temperatures at the end of the current section of the boiler counter-current heat exchanger model, and to calculate the quantification temperature and pressure within the heat exchange unit. The steam-water specific heat and density calculation module is used to calculate the specific heat capacity and density of the steam-water working fluid in this section of the boiler model based on the qualitative temperature and qualitative pressure of the boiler counter-current heat exchanger model in this section, through the physical property equation. The deviation comparison module is used to compare the deviations between the calculated results and the actual conditions of the flue gas temperature, steam-water working fluid temperature, steam-water working fluid pressure, and the metal wall temperature at the beginning of the boiler model after calculating the thermodynamic state quantities of the entire section of the boiler countercurrent heat exchanger model. The heat and flow calculation module is used to calculate the heat released per unit coal combustion and the valve flow coefficient of the boiler counter-current heat exchanger model based on the final obtained flue gas specific heat capacity and the thermodynamic state of the entire boiler model. The key thermodynamic parameter determination module is used to identify the key thermodynamic parameters of the thermal power unit under the current state based on the input operating conditions.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements a method for solving the key thermodynamic coefficients of the boiler in the secondary frequency modulation process as described in any one of claims 1 to 6.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a method for solving the key thermodynamic coefficients of the boiler in the secondary frequency modulation process as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements a method for solving the key thermodynamic coefficients of the boiler in the secondary frequency modulation process as described in any one of claims 1 to 6.

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