Fuel gas and steam combined generator set fuel gas amount adjusting method and device and storage medium

Abstract

The invention discloses a gas quantity adjusting method and device for a gas-steam combined generator set and a storage medium, and the method comprises the steps: obtaining the current operation environment and operation data of the gas-steam combined generator set, and calculating the output power of a gas turbine and the output power of a steam turbine; the method comprises the steps that an optimization objective function is constructed with the minimum unit power generation gas consumption as an objective, the gas inflow serves as an optimization variable, the optimal gas inflow is searched for through an optimization algorithm, the unit power generation gas consumption is the ratio of a gas input value to actual total output power, and the unit power generation gas consumption is the ratio of the gas input value to the actual total output power; the actual total output power is the sum of the gas turbine output power and the steam turbine output power; and the optimal gas inflow is issued to an execution mechanism, and the running state of the gas-steam combined generator set is adjusted. The unit power generation gas consumption is reduced on the premise that the power generation load is met, system energy-saving control is achieved, and a simple and convenient thought is provided for optimal adjustment of the gas inflow.

Description

Technical Field

[0001] The present invention relates to the technology of thermal process modeling and optimization, and particularly to a method, device and storage medium for regulating the gas volume of a gas-steam combined cycle power generation unit. Background Art

[0002] In the operation of a traditional gas-steam combined cycle unit, the gas consumption per unit power generation is relatively high and the system efficiency is relatively low under some operating conditions. For the mechanism modeling of a conventional gas-steam combined cycle unit, the modeling process is too complex and the cost is too high for the research on optimizing the gas intake. When using a modular modeling method such as Hammerstein model for modeling, the model can be built more quickly and conveniently. For the gas turbine, mechanism modeling is adopted, and the interaction rules of various parameters of the unit are analyzed by using the three major conservation laws, which can accurately reflect the dynamic / static characteristics of the system. However, the mechanism modeling process of the waste heat boiler involves complex structures and numerous processes, resulting in a very cumbersome modeling process. Moreover, the model is not easy to reproduce and the speed of later simulation operation is relatively slow. Due to the above limitations, the present invention adopts the identification method. Although the identification theory for linear systems is relatively mature at present, since the nonlinear characteristics exist in most physical processes, when the nonlinear characteristics of the physical process cannot be ignored, simply using a linear model to roughly describe the dynamic characteristics will affect the accuracy and application value of the model. Therefore, for a large gas-steam combined cycle unit, the present invention proposes a method of using the Hammerstein model structure for modeling. To improve the modeling accuracy, a static nonlinear characteristic model is established by using thermodynamic calculations, and a dynamic linear characteristic is established by using the data identification method. This method of separate modeling can take into account both the linear and nonlinear characteristics of the system, accurately describe the nonlinear dynamic characteristics of the entire physical process, and at the same time reduce the complexity of modeling and simulation calculations. In addition, this method of block modeling is more conducive to the research and design of control strategies. For the steam turbine part, due to the large inertia of the high-power rotor, the Hammerstein model modeling method can also be used for modeling to accurately reflect its dynamic and static characteristics. Summary of the Invention

[0003] Aiming at the problems in the prior art, such as the model being complex due to completely adopting mechanism modeling, being not conducive to the design of the control system, and having poor versatility, the present invention provides a method, device and storage medium for regulating the gas volume of a gas-steam combined cycle power generation unit. By using the Hammerstein model to obtain the change of the overall power generation capacity of the unit under different gas intakes, and combining with the real-time operation data, the optimal gas input amount is determined through a planning algorithm, so as to reduce the gas consumption per unit power generation on the premise of meeting the power generation load and realize the energy-saving control of the system.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A method for regulating the gas consumption of a gas-steam combined cycle power generation unit, where the gas-steam combined cycle power generation unit includes a gas turbine, a waste heat boiler, and a steam turbine connected in series in sequence. The method includes the following steps:

[0006] Obtain the current operating environment and operating data of the gas-steam combined cycle power generation unit for calculating the output power of the gas turbine and the output power of the steam turbine;

[0007] Construct an optimization objective function with the minimum gas consumption per unit power generation as the goal, use the gas intake as the optimization variable, and use an optimization algorithm to search for the optimal gas intake. The gas consumption per unit power generation is the ratio of the gas input value to the actual total output power, and the actual total output power is the sum of the output power of the gas turbine and the output power of the steam turbine;

[0008] Send the optimal gas intake to the actuator to adjust the operating state of the gas-steam combined cycle power generation unit.

[0009] To optimize the above technical solution, the specific measures taken also include:

[0010] Further, the obtaining of the current operating environment and operating data of the gas-steam combined cycle power generation unit includes: obtaining the gas consumption, air flow, atmospheric temperature, atmospheric pressure, and the enthalpy value of the working medium inside the waste heat boiler;

[0011] The calculation methods for the output power of the gas turbine and the output power of the steam turbine are as follows:

[0012] Input the gas consumption, air flow, atmospheric temperature, and atmospheric pressure into the simplified mechanism model of the gas turbine to obtain the output power of the gas turbine;

[0013] The enthalpy value of the working medium inside the waste heat boiler includes the enthalpy value of the gas turbine exhaust, the enthalpy value of the waste heat boiler exhaust, the enthalpy value of the high-pressure superheated steam, the enthalpy value of the medium-pressure superheated steam, the enthalpy value of the low-pressure superheated steam, the feed water enthalpy value at the inlet of the low-pressure economizer, the feed water enthalpy value at the outlet of the low-pressure economizer, the feed water enthalpy value at the outlet of the first-stage high-pressure economizer, the feed water enthalpy value at the outlet of the medium-pressure economizer, the enthalpy value of the flue gas at the inlet of the low-pressure evaporator, the enthalpy value of the flue gas at the inlet of the medium-pressure evaporator, the enthalpy value of the flue gas at the outlet of the high-pressure evaporator, the enthalpy value of the high-pressure saturated steam, the enthalpy value of the medium-pressure saturated steam, the enthalpy value of the low-pressure saturated steam, the enthalpy value of the steam at the outlet of the secondary reheater, and the enthalpy value of the steam at the inlet of the primary reheater;

[0014] Input the enthalpy value of the working medium inside the waste heat boiler into the Hammerstein model of the waste heat boiler to obtain the actual flow rates of the high-pressure superheated steam, medium-pressure superheated steam, and low-pressure superheated steam. Input the actual flow rates of the high-pressure superheated steam, medium-pressure superheated steam, and low-pressure superheated steam into the Hammerstein model of the steam turbine to obtain the output power of the steam turbine.

[0015] Furthermore, the method for constructing the simplified mechanism model of the gas turbine is as follows:

[0016] The structure of the gas turbine includes a compressor, a combustion chamber, and a gas turbine;

[0017] Based on the three conservation laws of mass conservation, energy conservation, and momentum conservation, a simplified mechanism model of the compressor is established;

[0018] Based on the three conservation laws of mass conservation, energy conservation, and momentum conservation, a simplified mechanism model of the combustion chamber is established;

[0019] Based on the three conservation laws of mass conservation, energy conservation, and momentum conservation, a simplified mechanism model of the gas turbine is established;

[0020] A volume module between the simplified mechanism model of the compressor and the simplified mechanism model of the combustion chamber is established, and the simplified mechanism model of the gas turbine is obtained by organizing the four parts: the simplified mechanism model of the compressor, the simplified mechanism model of the combustion chamber, the simplified mechanism model of the gas turbine, and the volume module.

[0021] Furthermore, the method for constructing the Hammerstein model of the waste heat boiler is as follows:

[0022] The Hammerstein model of the waste heat boiler is composed of a static nonlinear link and a dynamic linear link connected in series. The input of the static nonlinear link of the Hammerstein model of the waste heat boiler is the exhaust gas flow rate and exhaust gas temperature of the gas turbine, and the output is the theoretical flow rates of high, medium, and low pressure superheated steam; the input of the dynamic linear link of the Hammerstein model of the waste heat boiler is the theoretical flow rates of high, medium, and low pressure superheated steam, and the output is the actual flow rates of high, medium, and low pressure superheated steam;

[0023] The modeling method of the static nonlinear link of the Hammerstein model of the waste heat boiler is as follows:

[0024] Based on the design data of the gas-steam combined cycle power generation unit, the relationship between heat exchange and working medium temperature of the gas-steam combined cycle power generation unit is determined, and the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler is drawn;

[0025] In the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler, different operating condition sections are selected, and through reverse heat balance calculation, the theoretical flow rates of high, medium, and low pressure superheated steam are obtained as the output of the static nonlinear link of the Hammerstein model of the waste heat boiler;

[0026] The modeling method of the dynamic linear link of the Hammerstein model of the waste heat boiler is as follows:

[0027] Taking the theoretical flow rates of high, medium, and low-pressure steam obtained by reverse heat balance calculation as virtual identification intermediate parameters, based on the actual operating condition data of a gas-steam combined cycle power generation unit, its dynamic characteristics are identified to obtain the dynamic linear link of the waste heat boiler Hammerstein model.

[0028] Further, the construction method of the steam turbine Hammerstein model is as follows:

[0029] The steam turbine Hammerstein model is composed of a static non-linear link and a dynamic linear link in series. The input of the static non-linear link of the steam turbine Hammerstein model is the actual flow rates of high, medium, and low-pressure superheated steam, and the output is the theoretical output power of the steam turbine; the input of the dynamic linear link of the steam turbine Hammerstein model is the theoretical output power of the steam turbine, and the output is the actual output power of the steam turbine;

[0030] The modeling method of the static non-linear link of the steam turbine Hammerstein model is as follows:

[0031] Based on the actual flow rates of high, medium, and low-pressure superheated steam, the enthalpy drop method is used to calculate the theoretical output power of the steam turbine, which is used as the static non-linear link of the steam turbine Hammerstein model. The expression is as follows:

[0032] N st =G st (h st1 -h st2 )η ri

[0033] Where, N st represents the theoretical output power of the steam turbine, h st1 is the enthalpy of steam inlet; h st2 is the enthalpy of steam outlet; G st represents the actual flow rate of steam, and η ri is the relative internal efficiency of the steam turbine, which specifically represents the ratio of the actual enthalpy drop to the ideal enthalpy drop;

[0034] The modeling method of the dynamic linear link of the steam turbine Hammerstein model is as follows:

[0035] Taking the theoretical output power of the steam turbine as the virtual identification intermediate parameter, the virtual identification intermediate parameter is identified by the recursive least squares method to obtain a specific function, which is used as the dynamic linear link of the steam turbine Hammerstein model. It is expressed in the form of a transfer function as follows:

[0036]

[0037] Among them, G2(s) represents the transfer function of the dynamic linear link of the steam turbine Hammerstein model, K2 is the gain constant, T3 is the time constant, and s is the complex variable.

[0038] Furthermore, the static non-linear link of the waste heat boiler Hammerstein model adopts the form of a multi-variable coupled non-linear function; the waste heat boiler is a triple-pressure reheat waste heat boiler. In the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler, different operating condition segments are selected, and through reverse heat balance calculation, the theoretical flow rates of high, medium, and low-pressure superheated steam are obtained. The specific process of taking them as the output of the static non-linear link of the waste heat boiler Hammerstein model is as follows:

[0039] The overall working medium heat exchange relationship is as follows:

[0040] G g (i gin -i gpout ) = G SL (i OL -i WLin ) + G SM (i OM -i WLin ) + G SH (i oH -i WLin ) + (G SM + G SH )(i Z2 -i Z0 )(1)

[0041] In the formula, G g represents the flow rate of the gas turbine exhaust, i gin represents the enthalpy value of the gas turbine exhaust, i gpout represents the enthalpy value of the waste heat boiler exhaust, G SL represents the theoretical flow rate of low-pressure superheated steam, i OL is the enthalpy value of low-pressure superheated steam, i WLin is the feed water enthalpy value at the inlet of the low-pressure economizer, G SM represents the theoretical flow rate of medium-pressure superheated steam, i OM is the enthalpy value of medium-pressure superheated steam, G SH represents the theoretical flow rate of high-pressure superheated steam, i OH is the enthalpy value of high-pressure superheated steam, i Z2 is the enthalpy value of the steam at the outlet of the secondary reheater, i Z0 is the enthalpy value of the steam at the inlet of the primary reheater;

[0042] The heat exchange relationship of the working medium inside the low-pressure economizer is as follows:

[0043] G g (igls -i gpout ) = (G SL +G SM +G SH )(i W1 -i WLin ) (2)

[0044] Wherein, i gls is the enthalpy value of the flue gas at the inlet of the low-pressure evaporator, and i W1 is the enthalpy value of the feed water at the outlet of the low-pressure economizer;

[0045] The heat exchange relationship of the working medium after the low-pressure superheater is as follows:

[0046] G g (i glg -i gpout ) = G SL (i OL -i WLin ) + G SM (i W3 -i WLin ) + G SH (i W2 -i LLin ) (3)

[0047] Wherein, i glg is the enthalpy value of the flue gas at the inlet of the medium-pressure evaporator, i W3 is the enthalpy value of the feed water at the outlet of the medium-pressure economizer, and i W2 is the enthalpy value of the feed water at the outlet of the first-stage high-pressure economizer;

[0048] The heat exchange relationship of the working medium after the medium-pressure superheater is as follows:

[0049] G g [[ID=�7]](i ggz -i gpout ) = G SL (i OL -i WLin ) + G SM (i OM -i WLin ) + G SH (i SH -i WLin ) (4)

[0050] Wherein, i ggz is the enthalpy value of the flue gas at the outlet of the high-pressure evaporator, i SH is the enthalpy value of the high-pressure saturated steam,

[0051] By combining equations (1) to (4) and solving for the theoretical flow rates of the high-, medium-, and low-pressure steams, we get:

[0052]

[0053]

[0054] Equations (5) to (7) are the static non - linear links of the Hammerstein model of the waste heat boiler in the form of multi - variable coupled non - linear functions.

[0055] Furthermore, the dynamic linear link of the Hammerstein model of the waste heat boiler adopts the form of a transfer function, and the formula is expressed as follows:

[0056]

[0057] Wherein, G1(s) is the dynamic linear link of the Hammerstein model of the waste heat boiler in the form of a transfer function, K1 is the gain constant, T1 and T2 are the time constants, n1 and n2 are the orders, and s is the complex variable.

[0058] Furthermore, the specific optimization objective function is:

[0059]

[0060] Wherein, J(F) is the optimization objective function, F is the gas inlet volume, P(F) is the output power of the gas turbine, and W(F) is the output power of the steam turbine;

[0061] The constraint conditions of the objective function are as follows:

[0062] The gas inlet volume is within the controllable range of the gas inlet system:

[0063] F min ≤F≤F max

[0064] F min is the minimum inlet volume of the gas inlet system, and F max is the maximum inlet volume of the gas inlet system;

[0065] The total power generated by the optimal gas inlet volume meets the load demand:

[0066] P(F)+W(F)≥D

[0067] D is the load demand;

[0068] The temperature, flow rate, and working medium enthalpy value do not exceed the design upper limit.

[0069] The present invention also provides an electronic device, including: a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the computer program, the gas volume regulation method of the gas - steam combined power generation unit as described above is implemented.

[0070] The present invention also provides a computer-readable storage medium storing a computer program, which causes a computer to execute the gas quantity regulation method for a gas-steam combined cycle power generation unit as described above.

[0071] The beneficial effects of the present invention are as follows: The present invention adopts a gas quantity optimization regulation method for a gas combined cycle unit based on a Hammerstein model of reverse heat balance calculation, integrating the advantages of modular modeling, mechanism modeling, and system identification. A Hammerstein model is established for the gas combined cycle unit based on reverse heat balance calculation. The physical meanings of the parameters are clear, the structure is simple, and the Hammerstein model reflects the nonlinear dynamic characteristics of each main link of the system. The model has high accuracy. By using this model to obtain the change of the overall power generation capacity of the unit under different gas inlet quantities, combined with real-time operation data, the optimal gas input quantity is determined through a planning algorithm, reducing the unit power generation gas consumption under the premise of meeting the power generation load, realizing energy-saving control of the system, and providing a simple idea for the optimal regulation of the gas inlet quantity. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 is a flowchart of the gas quantity regulation method for a gas-steam combined cycle power generation unit based on a Hammerstein model of reverse heat balance calculation according to an embodiment of the present invention;

[0073] Figure 2 is a diagram of the temperature difference at key nodes of each component of the waste heat boiler according to an embodiment of the present invention;

[0074] Figure 3 is a schematic diagram of the overall model structure of the gas quantity regulation method for a gas-steam combined cycle power generation unit based on a Hammerstein model of reverse heat balance calculation according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0075] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0076] Embodiment 1

[0077] The present invention provides a gas quantity regulation method for a gas-steam combined cycle power generation unit, specifically a gas quantity regulation method for a gas-steam combined cycle power generation unit based on a Hammerstein model of reverse heat balance calculation. The gas-steam combined cycle power generation unit includes a gas turbine, a waste heat boiler, and a steam turbine connected in series in sequence. The flowchart of this method is as Figure 1 shown, and includes the following steps:

[0078] Step 1: Obtain the current operating environment and operating data of the gas-steam combined cycle power generation unit for calculating the output power of the gas turbine and the output power of the steam turbine. Obtaining the current operating environment and operating data of the gas-steam combined cycle power generation unit includes: obtaining the gas consumption, air flow rate, atmospheric temperature, atmospheric pressure, and the enthalpy value of the working medium inside the waste heat boiler.

[0079] The calculation methods for the output power of the gas turbine and the output power of the steam turbine are as follows:

[0080] Input the gas consumption, air flow rate, atmospheric temperature, and atmospheric pressure into the simplified mechanism model of the gas turbine to obtain the output power of the gas turbine.

[0081] The enthalpy value of the working medium inside the waste heat boiler includes the enthalpy value of the gas turbine exhaust gas, the enthalpy value of the waste heat boiler exhaust gas, the enthalpy value of the high-pressure superheated steam, the enthalpy value of the medium-pressure superheated steam, the enthalpy value of the low-pressure superheated steam, the feed water enthalpy value at the inlet of the low-pressure economizer, the feed water enthalpy value at the outlet of the low-pressure economizer, the feed water enthalpy value at the outlet of the first-stage high-pressure economizer, the feed water enthalpy value at the outlet of the medium-pressure economizer, the enthalpy value of the flue gas at the inlet of the low-pressure evaporator, the enthalpy value of the flue gas at the inlet of the medium-pressure evaporator, the enthalpy value of the flue gas at the outlet of the high-pressure evaporator, the enthalpy value of the high-pressure saturated steam, the enthalpy value of the medium-pressure saturated steam, the enthalpy value of the low-pressure saturated steam, the enthalpy value of the steam at the outlet of the secondary reheater, and the enthalpy value of the steam at the inlet of the primary reheater.

[0082] Input the enthalpy value of the working medium inside the waste heat boiler into the Hammerstein model of the waste heat boiler to obtain the actual flow rates of the high-pressure superheated steam, the medium-pressure superheated steam, and the low-pressure superheated steam. Input the actual flow rates of the high-pressure superheated steam, the medium-pressure superheated steam, and the low-pressure superheated steam into the Hammerstein model of the steam turbine to obtain the output power of the steam turbine.

[0083] The construction method of the simplified mechanism model of the gas turbine is as follows:

[0084] The structure of the gas turbine includes a compressor, a combustion chamber, and a gas turbine.

[0085] Establish a simplified mechanism model of the compressor based on the three conservation laws of mass conservation, energy conservation, and momentum conservation.

[0086] Establish a simplified mechanism model of the combustion chamber based on the three conservation laws of mass conservation, energy conservation, and momentum conservation.

[0087] Establish a simplified mechanism model of the gas turbine based on the three conservation laws of mass conservation, energy conservation, and momentum conservation.

[0088] Establish a volume module between the simplified compressor mechanism model and the simplified combustor mechanism model, and organize the simplified compressor mechanism model, the simplified combustor mechanism model, the simplified gas turbine mechanism model, and the volume module to obtain the simplified mechanism model of the gas turbine. The specific implementation method is as follows:

[0089] Based on the three conservation laws of mass conservation, energy conservation, and momentum conservation, establish a simplified compressor mechanism model:

[0090] Total temperature at the compressor inlet: T1 * = T a

[0091] Compressor reduced speed:

[0092] Compressor reduced flow rate:

[0093] Compressor pressure ratio: π c = P2 * / P1 *

[0094] Total temperature at the compressor outlet:

[0095] Compressor work consumption:

[0096] Among them, T a - Atmospheric temperature (K), P a is the atmospheric pressure (Pa), P2 * is the total pressure at the compressor outlet (Pa), λ a = 1.4 is the air adiabatic index, C pa = 904.6 [J / (kg·K) is the specific heat at constant pressure of air.

[0097] According to the characteristic curve of the compressor, use the fitting algorithm for fitting. It can be known that the relationship between the pressure ratio and efficiency of the compressor and the speed and flow rate is as follows:

[0098]

[0099] Among them, the one with the superscript · is the specific reduced parameter. is the specific reduced pressure ratio, is the specific reduced mass flow rate, is the specific reduced speed. Each The expression is as follows:

[0100]

[0101] Among them, a, b, and c4 are all constants, a = b = 1.8, c4 = 0.3.

[0102] Then, calculate the outlet temperature and input power of the compressor according to the above formula:

[0103]

[0104] Based on the three conservation laws of mass conservation, energy conservation, and momentum conservation, establish a simplified mechanism model of the combustion chamber

[0105] Inlet air flow rate of the combustion chamber: M B =(1 - g cl )M C

[0106] Outlet flow rate of the combustion chamber: M BT = M B + M f

[0107] Outlet pressure of the combustion chamber: P3 = α2P2

[0108] Outlet temperature of the combustion chamber:

[0109] Among them, g cl is the flow loss coefficient, M f is the fuel consumption (kg / s), LHV is the lower heating value of the fuel (J / kg), C pg is the specific heat capacity at constant pressure of the fuel, taking 1154 [J / kg·K], η B is the combustion efficiency, i f is the physical enthalpy of the fuel (J / kg).

[0110] Based on the three conservation laws of mass conservation, energy conservation, and momentum conservation, establish a simplified mechanism model of the gas turbine:

[0111] Reduced flow rate of the turbine:

[0112] Reduced rotational speed of the turbine:

[0113] Expansion ratio of the gas turbine: π t = P3 * / P4 *

[0114] The expansion ratio π of the turbine T is also a function of M T and n T According to the Flugel formula, the expansion ratio of the turbine can be described as follows:

[0115]

[0116] Among them,

[0117] The efficiency expression of the gas turbine is as follows:

[0118]

[0119] Ignoring the heat loss in the air passage from the combustion chamber to the gas turbine, the outlet temperature of the combustion chamber is considered as the inlet temperature of the turbine. Thus, the outlet temperature and power of the gas turbine are calculated according to the following formula.

[0120] Turbine exhaust temperature:

[0121] Turbine output power:

[0122] Where λ g = 1.33 is the average specific heat ratio of the gas.

[0123] A volume module is established between the simplified mechanism model of the compressor and the simplified mechanism model of the combustion chamber. The simplified mechanism model of the gas turbine is obtained by organizing these four parts as follows:

[0124] The entire flow space is regarded as a whole. There is a connecting part between the compressor and the combustion chamber. Due to the compressibility of the working fluid in the actual process, the amount of gas contained in the volume changes, so there is a difference in the inflow and outflow flow rates, resulting in different inlet and outlet parameters.

[0125]

[0126] Among them, V is the volume of the cavity, m[[ID=۳۶]] 3 ; ρ is the fluid density, kg / m 3 ;

[0127] The simplified mechanism model of the gas turbine is obtained by organizing the four parts.

[0128] The construction method of the Hammerstein model of the waste heat boiler is as follows:

[0129] The Hammerstein model of the waste heat boiler is composed of a static nonlinear link and a dynamic linear link in series. The input of the static nonlinear link of the Hammerstein model of the waste heat boiler is the exhaust gas flow rate and exhaust gas temperature of the gas turbine, and the output is the theoretical flow rates of high, medium, and low pressure superheated steam; the input of the dynamic linear link of the Hammerstein model of the waste heat boiler is the theoretical flow rates of high, medium, and low pressure superheated steam, and the output is the actual flow rates of high, medium, and low pressure superheated steam;

[0130] The modeling method of the static nonlinear link of the Hammerstein model of the waste heat boiler is as follows:

[0131] Based on the design data of a gas-steam combined cycle power generation unit, determine the relationship between heat exchange and working fluid temperature of the gas-steam combined cycle power generation unit, and draw the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler; the trend of the working fluid temperature difference in the waste heat boiler is determined by the unit structure and design parameters. The flow direction of the steam generated by the waste heat boiler is opposite to the flue gas flow direction. Arrange each heat exchange component in the waste heat boiler from left to right according to the flue gas flow direction, and draw the heat exchange temperature difference curve of each component according to the working fluid temperature difference at the key nodes. The overall curves of each component constitute the temperature difference diagram of key nodes of each component of the waste heat boiler.

[0132] Taking a triple-pressure reheat waste heat boiler as an example, it is equipped with economizers, evaporators, superheaters and reheaters at high, medium and low pressure levels. These heat exchange devices are arranged in series independently and orderly in structure and are connected to each other functionally, jointly constituting the thermal cycle system of the boiler. According to its layout structure, the temperature difference diagram of key nodes of each component can be drawn as Figure 2 shown.

[0133] Select different operating condition segments in the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler, and through reverse heat balance calculation, obtain the theoretical flow rates of high, medium and low pressure superheated steam, which are used as the output of the static non-linear link of the Hammerstein model of the waste heat boiler.

[0134] The static non-linear link can be in various forms, such as polynomials, piecewise linear functions, neural networks, fuzzy systems. In this embodiment, the static non-linear link of the Hammerstein model of the waste heat boiler adopts the form of a multi-variable coupled non-linear function; the waste heat boiler is a triple-pressure reheat waste heat boiler. The specific process of selecting different operating condition segments in the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler and obtaining the theoretical flow rates of high, medium and low pressure superheated steam through reverse heat balance calculation as the output of the static non-linear link of the Hammerstein model of the waste heat boiler is as follows:

[0135] The overall working fluid heat exchange relationship is as follows:

[0136] G g (i gin -i gpout )=G SL (i OL -i WLin )+G SM (i OM -i WLin )+G SH (i OH -i WLin )+(G SM +G SH )(i Z2 -i Z0 )(1)

[0137] In the formula, G g represents the flow rate of the gas turbine exhaust, kg / s, and i gon represents the enthalpy value of the gas turbine exhaust, kJ / kg; i gin = c p,in ·t gin , where c p,in is taken as 1.2445; i gpout represents the enthalpy value of the exhaust of the waste heat boiler, kJ / kg; i gpout = c p,out ·t gpout , and the exhaust temperature is taken as 77°C; G SL represents the theoretical flow rate of the low-pressure superheated steam, kg / s, and i OL is the enthalpy value of the low-pressure superheated steam, i WLin is the feed water enthalpy value at the inlet of the low-pressure economizer, G SM represents the theoretical flow rate of the medium-pressure superheated steam, i OM is the enthalpy value of the medium-pressure superheated steam, kJ / kg, G SH represents the theoretical flow rate of the high-pressure superheated steam, i OH is the enthalpy value of the high-pressure superheated steam, i Z2 is the enthalpy value of the steam at the outlet of the secondary reheater, i Z0 is the enthalpy value of the steam at the inlet of the primary reheater;

[0138] The heat exchange relationship of the working medium inside the low-pressure economizer is as follows:

[0139] G g (i gls - i gpout ) = (G SL + G SM + G SH )(i W1 - i WLin )(2)

[0140] In the formula, i gls is the enthalpy value of the flue gas at the inlet of the low-pressure evaporator, i W1 is the feed water enthalpy value at the outlet of the low-pressure economizer;

[0141] The heat exchange relationship of the working medium after the low-pressure superheater is as follows:

[0142] G g (i glg - i gpout ) = G SL (i OL - i WLin ) + G SM (i W3 - i WLin ) + G SH (iW2 -i WLin )(3)

[0143] Wherein, i glg is the enthalpy value of the flue gas at the inlet of the medium-pressure evaporator, and i W3 is the feed water enthalpy value at the outlet of the medium-pressure economizer, and i W2 is the feed water enthalpy value at the outlet of the first-stage high-pressure economizer;

[0144] The heat exchange relationship of the working medium after the medium-pressure superheater is as follows:

[0145] G g (i ggz -i gpout ) = G SL (i OL -i WLin ) + G SM (i OM -i WLin ) + G SH (i SH -i WLin )(4)

[0146] Wherein, i ggz is the enthalpy value of the flue gas at the outlet of the high-pressure evaporator, and i SH is the enthalpy value of the high-pressure saturated steam,

[0147] By combining equations (1) to (4) and solving for the theoretical flow rates of high, medium, and low-pressure steam, we obtain:

[0148]

[0149]

[0150] Equations (5) to (7) are the static nonlinear links of the Hammerstein model of the waste heat boiler in the form of a multi-variable coupled non-linear function.

[0151] The modeling method for the dynamic linear link of the Hammerstein model of the waste heat boiler is as follows:

[0152] Using the theoretical flow rates of high, medium, and low-pressure steam obtained from the reverse heat balance calculation as virtual identification intermediate parameters, and identifying its dynamic characteristics based on the actual operating conditions data of the gas-steam combined cycle power generation unit, to obtain the dynamic linear link of the Hammerstein model of the waste heat boiler. The form of the dynamic linear link is also diverse, and it can be a difference equation, a transfer function, or an ARX model. In this embodiment, the dynamic linear link of the Hammerstein model of the waste heat boiler adopts the form of a transfer function, and the formula is expressed as follows:

[0153]

[0154] In the formula, G1(s) is the dynamic linear link of the waste heat boiler Hammerstein model in the form of a transfer function, K1 is the gain constant, T1 and T2 are the time constants, n1 and n2 are the orders, and s is the complex variable.

[0155] The construction method of the steam turbine Hammerstein model is as follows:

[0156] The steam turbine Hammerstein model is composed of a static nonlinear link and a dynamic linear link in series. The input of the static nonlinear link of the steam turbine Hammerstein model is the actual flow rates of high, medium, and low pressure superheated steam, and the output is the theoretical output power of the steam turbine; the input of the dynamic linear link of the steam turbine Hammerstein model is the theoretical output power of the steam turbine, and the output is the actual output power of the steam turbine;

[0157] The modeling method of the static nonlinear link of the steam turbine Hammerstein model is as follows:

[0158] The dynamic characteristics of the steam turbine are mainly reflected in the inertia of the high-power rotor itself. Based on the actual flow rates of high, medium, and low pressure superheated steam, the enthalpy drop method is used to calculate the theoretical output power of the steam turbine, which is used as the static nonlinear link of the steam turbine Hammerstein model. The expression is as follows:

[0159] N st =G st (h st1 -h st2 )η ri

[0160] Among them, N st represents the theoretical output power of the steam turbine, h st1 is the enthalpy of the steam inlet; h st2 is the enthalpy of the steam outlet; G st represents the actual flow rate of the steam, and η ri is the relative internal efficiency of the steam turbine, which specifically represents the ratio of the actual enthalpy drop to the ideal enthalpy drop;

[0161] The modeling method of the dynamic linear link of the steam turbine Hammerstein model is as follows:

[0162] Taking the theoretical output power of the steam turbine as the virtual identification intermediate parameter, the virtual identification intermediate parameter is identified by the recursive least squares method to obtain a specific function, which is used as the dynamic linear link of the steam turbine Hammerstein model and is expressed in the form of a transfer function as follows:

[0163]

[0164] Where G2(s) represents the transfer function of the dynamic linear link of the Hammerstein model of the steam turbine, K2 is the gain constant, T3 is the time constant, and s is a complex variable.

[0165] Step 2: Construct an optimization objective function with the goal of minimizing the unit power generation gas consumption. Use the gas intake volume as the optimization variable and use an optimization algorithm to search for the optimal gas intake volume. The optimization algorithm can be the golden section search method, Newton iteration method, or particle swarm optimization. The unit power generation gas consumption is the ratio of the gas input value to the actual total output power. The actual total output power is the sum of the gas turbine output power and the steam turbine output power. The optimization objective function is specifically:

[0166]

[0167] Where, J(F) is the optimization objective function, F is the gas intake volume, P(F) is the gas turbine output power, and W(F) is the steam turbine output power;

[0168] The constraints of the objective function are as follows:

[0169] The gas intake volume is within the controllable range of the gas intake system:

[0170] F min ≤F≤F max

[0171] F min is the minimum intake volume of the gas intake system, F max is the maximum air intake volume of the gas intake system;

[0172] The total power generated by the optimal gas intake volume meets the load requirements:

[0173] P(F)+W(F)≥D

[0174] D is the load demand;

[0175] The temperature, flow rate and working fluid enthalpy values do not exceed the design upper limit.

[0176] Step 3: Send the optimal gas intake volume to the actuator (such as the gas valve, compressor) to adjust the operating status of the gas-steam combined generator set.

[0177] Example 2

[0178] The present invention provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the method for regulating the gas quantity of a gas-steam combined generator set as described in Example 1 is implemented.

[0179] Example 3

[0180] The present invention provides a computer-readable storage medium storing a computer program, and the computer program causes a computer to execute the gas quantity regulation method of a gas-steam combined cycle power generation unit as described in Embodiment 1.

[0181] According to the established gas quantity optimization regulation method for a gas combined cycle unit based on the Hammerstein model of reverse heat balance, a simulation model is built on a computer for numerical simulation. The schematic diagram of the overall model structure of the gas quantity optimization regulation method for a gas combined cycle unit based on the Hammerstein model of reverse heat balance is as Figure 3 shown. Table 1 is a comparison between the simulation output results obtained from the input signals of the gas turbine model and the actual unit data.

[0182] Table 1 Comparison between Gas Turbine Simulation Output and Actual Data

[0183]

[0184] Table 2 Comparison between Simulation Output and Actual Data of the Heat Recovery Steam Generator and Steam Turbine

[0185]

[0186] Experimental data show that the relative errors between the simulation outputs of the gas turbine, heat recovery steam generator, and steam turbine models and the actual data are all less than 5%, verifying the effectiveness of the models.

[0187] In the embodiments disclosed in the present application, the computer storage medium may be a tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. The computer storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of the computer storage medium would include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0188] Those of ordinary skill in the art can realize that the units and algorithm steps of the examples described in combination with the embodiments disclosed in the present application can be implemented by electronic hardware or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0189] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions falling within the concept of the present invention belong to the protection scope of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and refinements made without departing from the principle of the present invention should be regarded as within the protection scope of the present invention.

Claims

1. A method for regulating the gas volume of a gas-steam combined cycle power generation unit, the gas-steam combined cycle power generation unit comprising a gas turbine, a waste heat boiler and a steam turbine connected in series in sequence, characterized in that, The method includes the following steps: Obtain the current operating environment and operating data of the gas-steam combined cycle power generation unit for calculating the output power of the gas turbine and the output power of the steam turbine; Construct an optimization objective function with the minimum gas consumption per unit power generation as the goal, use the gas intake as the optimization variable, and use an optimization algorithm to search for the optimal gas intake. The gas consumption per unit power generation is the ratio of the gas input value to the actual total output power, and the actual total output power is the sum of the output power of the gas turbine and the output power of the steam turbine; Send the optimal gas intake to the actuator to adjust the operating state of the gas-steam combined cycle power generation unit.

2. The gas quantity regulation method for a gas-steam combined cycle power generation unit as described in claim 1, characterized in that, The obtaining of the current operating environment and operating data of the gas-steam combined cycle power generation unit includes: obtaining the gas consumption, air flow, atmospheric temperature, atmospheric pressure, and the enthalpy value of the working medium inside the waste heat boiler; The calculation methods for the output power of the gas turbine and the output power of the steam turbine are as follows: Input the gas consumption, air flow, atmospheric temperature, and atmospheric pressure into the simplified mechanism model of the gas turbine to obtain the output power of the gas turbine; The enthalpy values of the working medium inside the waste heat boiler include the enthalpy value of the gas turbine exhaust, the enthalpy value of the waste heat boiler exhaust, the enthalpy value of the high-pressure superheated steam, the enthalpy value of the medium-pressure superheated steam, the enthalpy value of the low-pressure superheated steam, the feed water enthalpy value at the inlet of the low-pressure economizer, the feed water enthalpy value at the outlet of the low-pressure economizer, the feed water enthalpy value at the outlet of the first-stage high-pressure economizer, the feed water enthalpy value at the outlet of the medium-pressure economizer, the enthalpy value of the flue gas at the inlet of the low-pressure evaporator, the enthalpy value of the flue gas at the inlet of the medium-pressure evaporator, the enthalpy value of the flue gas at the outlet of the high-pressure evaporator, the enthalpy value of the high-pressure saturated steam, the enthalpy value of the medium-pressure saturated steam, the enthalpy value of the low-pressure saturated steam, the enthalpy value of the steam at the outlet of the secondary reheater, and the enthalpy value of the steam at the inlet of the primary reheater; Input the enthalpy values of the working medium inside the waste heat boiler into the Hammerstein model of the waste heat boiler to obtain the actual flow rates of the high-pressure superheated steam, medium-pressure superheated steam, and low-pressure superheated steam. Input the actual flow rates of the high-pressure superheated steam, medium-pressure superheated steam, and low-pressure superheated steam into the Hammerstein model of the steam turbine to obtain the output power of the steam turbine.

3. The gas quantity regulation method for a gas-steam combined cycle power generation unit according to claim 2, characterized in that, The construction method of the simplified mechanism model of the gas turbine is as follows: The structure of the gas turbine includes a compressor, a combustion chamber, and a gas turbine; Establish a simplified mechanism model of the compressor based on the three conservation laws of mass conservation, energy conservation, and momentum conservation; Establish a simplified mechanism model of the combustion chamber based on the three conservation laws of mass conservation, energy conservation, and momentum conservation; Establish a simplified mechanism model of the gas turbine based on the three conservation laws of mass conservation, energy conservation, and momentum conservation; Establish a volume module between the simplified mechanism model of the compressor and the simplified mechanism model of the combustion chamber, and organize the four parts of the simplified mechanism model of the compressor, the simplified mechanism model of the combustion chamber, the simplified mechanism model of the gas turbine, and the volume module to obtain the simplified mechanism model of the gas turbine.

4. The gas quantity regulation method for a gas-steam combined cycle power generation unit as claimed in claim 2, wherein The construction method of the Hammerstein model of the waste heat boiler is: The Hammerstein model of the waste heat boiler is composed of a static nonlinear link and a dynamic linear link connected in series. The input of the static nonlinear link of the Hammerstein model of the waste heat boiler is the exhaust gas flow rate and exhaust gas temperature of the gas turbine, and the output is the theoretical flow rates of high, medium, and low pressure superheated steam. The input of the dynamic linear link of the Hammerstein model of the waste heat boiler is the theoretical flow rates of high, medium, and low pressure superheated steam, and the output is the actual flow rates of high, medium, and low pressure superheated steam. The modeling method of the static nonlinear link of the Hammerstein model of the waste heat boiler is as follows: Based on the design data of the gas-steam combined cycle power generation unit, determine the relationship between heat exchange and working medium temperature of the gas-steam combined cycle power generation unit, and draw the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler. Select different working condition segments in the temperature difference diagram of key nodes of each heat exchange component of the waste heat boiler, and through reverse heat balance calculation, obtain the theoretical flow rates of high, medium, and low pressure superheated steam, which are used as the output of the static nonlinear link of the Hammerstein model of the waste heat boiler. The modeling method of the dynamic linear link of the Hammerstein model of the waste heat boiler is as follows: Taking the theoretical flow rates of high, medium, and low pressure steam obtained by reverse heat balance calculation as virtual identification intermediate parameters, identify its dynamic characteristics based on the actual working condition data of the gas-steam combined cycle power generation unit, and obtain the dynamic linear link of the Hammerstein model of the waste heat boiler.

5. The gas quantity regulation method for a gas-steam combined cycle power generation unit according to claim 2, characterized in that, The construction method of the Hammerstein model of the steam turbine is as follows: The Hammerstein model of the steam turbine is composed of a static nonlinear link and a dynamic linear link connected in series. The input of the static nonlinear link of the Hammerstein model of the steam turbine is the actual flow rates of high, medium, and low pressure superheated steam, and the output is the theoretical output power of the steam turbine. The input of the dynamic linear link of the Hammerstein model of the steam turbine is the theoretical output power of the steam turbine, and the output is the actual output power of the steam turbine. The modeling method of the static nonlinear link of the Hammerstein model of the steam turbine is as follows: Based on the actual flow rates of high, medium, and low pressure superheated steam, use the enthalpy drop method to calculate the theoretical output power of the steam turbine, which is used as the static nonlinear link of the Hammerstein model of the steam turbine. The expression is as follows: N st = G st (h st1 - h st2 ) η ri Among them, N st represents the theoretical output power of the steam turbine, h st1 is the enthalpy at the steam inlet; h st2 is the enthalpy at the steam outlet; G st represents the actual steam flow rate, η ri is the relative internal efficiency of the steam turbine, specifically representing the ratio of the actual enthalpy drop to the ideal enthalpy drop; The modeling method of the dynamic linear link of the Hammerstein model of the steam turbine is as follows: Taking the theoretical output power of the steam turbine as the virtual identification intermediate parameter, identify the virtual identification intermediate parameter by the recursive least squares method to obtain a specific function, which is used as the dynamic linear link of the Hammerstein model of the steam turbine. It is expressed in the form of a transfer function as follows: Among them, G2(s) represents the transfer function of the dynamic linear link of the Hammerstein model of the steam turbine, K2 is the gain constant, T3 is the time constant, and s is the complex variable.

6. The gas quantity regulation method for a gas-steam combined cycle power generation unit as described in claim 4, characterized in that, The static nonlinear link of the Hammerstein model of the waste heat boiler adopts the form of a multivariable coupled nonlinear function; the waste heat boiler is a three-pressure reheat waste heat boiler. Different operating conditions are selected from the temperature difference diagram of the key nodes of each heat exchange component of the waste heat boiler, and the high, medium and low pressure superheated steam theoretical flow rates are obtained through reverse heat balance calculation as the output of the static nonlinear link of the Hammerstein model of the waste heat boiler. The specific process is as follows: The overall working fluid heat exchange relationship is as follows: G g (i gin -i gpout ) = G SL (i OL -i WLin ) + G SM (i OM -i WLin ) + G SH (i OH -i WLin ) + (G SM + G SH )(i Z2 -i Z0 )(1) Wherein, G g represents the flow rate of the exhaust gas of the gas turbine, and i gin represents the enthalpy value of the exhaust gas of the gas turbine, and i gpout represents the enthalpy value of the exhaust gas of the waste heat boiler, and G SL represents the theoretical flow rate of the low-pressure superheated steam, and i OL is the enthalpy value of the low-pressure superheated steam, and i WLin is the enthalpy value of the feed water at the inlet of the low-pressure economizer, and G SM represents the theoretical flow rate of the medium-pressure superheated steam, and i OM is the enthalpy value of the medium-pressure superheated steam, and G SH represents the theoretical flow rate of the high-pressure superheated steam, and i OH is the enthalpy value of the high-pressure superheated steam, and i Z2 is the enthalpy value of the steam at the outlet of the secondary reheater, and i Z0 is the enthalpy value of the steam at the inlet of the primary reheater; The heat exchange relationship of the working fluid inside the low-pressure economizer is as follows: G g (i gls -i gpout )=(G SL +G SM +G SH )(i W1 -i WLin ) (2) where, i gls is the enthalpy value of the flue gas at the inlet of the low-pressure evaporator, and i W1 is the feed water enthalpy value at the outlet of the low-pressure economizer; The heat exchange relationship of the working fluid after the low-pressure superheater is as follows: G g (i glg -i gpout ) = G SL (i OL -i WLin ) + G SM (i W3 -i WLin ) + G SH (i W2 -i WLin ) (3) where, i glg is the enthalpy value of the flue gas at the inlet of the medium-pressure evaporator, i W3 is the feed-water enthalpy value at the outlet of the medium-pressure economizer, i W2 is the feed-water enthalpy value at the outlet of the first-stage high-pressure economizer; The heat exchange relationship of the working fluid after the medium-pressure superheater is as follows: G g (i ggz -i gpout ) = G SL (i OL -i WLin ) + G SM (i OM -i WLin ) + G SH (i SH -i WLin ) (4) where, i ggz is the enthalpy value of the flue gas at the outlet of the high-pressure evaporator, and i SH is the enthalpy value of the high-pressure saturated steam. By combining equations (1) to (4), and solving the theoretical flow rates of high, medium, and low pressure steam, we obtain: Equations (5) to (7) are the static nonlinear links of the waste heat boiler Hammerstein model in the form of multivariable coupled nonlinear functions.

7. The gas quantity regulation method for a gas-steam combined cycle generating unit according to claim 4, characterized in that The dynamic linear link of the waste heat boiler Hammerstein model adopts the form of transfer function, which is expressed as follows: Where G1(s) is the dynamic linear link of the waste heat boiler Hammerstein model in the form of a transfer function, K1 is the gain constant, T1 and T2 are time constants, n1 and n2 are orders, and s is a complex variable.

8. The gas quantity regulation method for a gas-steam combined cycle power generation unit according to claim 1, characterized in that, The optimization objective function is specifically: Where, J(F) is the optimization objective function, F is the gas intake volume, P(F) is the gas turbine output power, and W(F) is the steam turbine output power; The constraints of the objective function are as follows: The gas intake volume is within the controllable range of the gas intake system: F min F ≤ F ≤ F max F min is the minimum intake air volume of the gas intake system, F max is the maximum intake air volume of the gas intake system; The total power generated by the optimal gas intake volume meets the load requirements: P(F)+W(F)≥D D is the load demand; The temperature, flow rate and working fluid enthalpy values do not exceed the design upper limit.

9. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for regulating the gas quantity of a gas-steam combined power generation unit according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium storing a computer program, characterized in that, The computer program enables a computer to execute the method for regulating the gas quantity of a gas-steam combined power generation unit according to any one of claims 1 to 8.

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