Optimized operation analysis method and device for cogeneration unit based on reheating temperature

Abstract

The invention is suitable for the technical field of cogeneration unit analysis, and provides a cogeneration unit optimization operation analysis method and device based on reheating temperature, and the method comprises the steps: obtaining a plurality of target working conditions of a cogeneration unit; determining an energy consumption fitting formula based on the load data and the energy consumption data under the plurality of target working conditions; obtaining a demand load of the cogeneration unit, and calculating a first operation benefit of the unit before operation optimization based on the demand load and an energy consumption fitting formula; the reheating temperature under the working condition of the required load before operation optimization is determined as the first reheating temperature; determining a second reheat temperature for operation optimization based on the first reheat temperature; calculating a second operation benefit of the unit after operation optimization based on the demand load and the second reheating temperature; the second reheating temperature is lower than the first reheating temperature; and determining an operation benefit analysis result of the unit based on the first operation benefit and the second operation benefit. According to the method, the operation optimization of the unit can be efficiently analyzed.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and in particular relates to a method and device for analyzing the optimized operation of a cogeneration unit based on reheat temperature. Background Art

[0002] Achieving cogeneration through the supply of industrial steam can improve the economic efficiency and efficiency of coal-fired units, contributing to the dual carbon goals. In recent years, regional industrial heat demand has continued to increase in northern my country. Currently, when units are operating at low load, rotating baffles are commonly used to throttle steam supply. This can cause industrial extraction steam temperatures to exceed material limits, endangering unit operation safety. Therefore, the steam supply operation method of cogeneration units needs to be optimized.

[0003] However, optimizing the steam supply and operating mode of a CHP unit will affect its output and operating efficiency. Therefore, addressing the issue of industrial extraction steam temperature exceeding the limit by changing the CHP unit's steam supply and operating mode requires a comprehensive analysis of the CHP unit's output and operating efficiency. Furthermore, comprehensive analysis of the CHP unit requires a comprehensive understanding of its specific operating conditions, which requires extensive computation and is costly, hindering efficient analysis. Summary of the Invention

[0004] The embodiments of the present invention provide a method and device for analyzing the optimized operation of a cogeneration unit based on reheat temperature, so as to achieve efficient analysis of the operating benefits of the cogeneration unit before and after the optimized operation, thereby better verifying the feasibility of the current optimization means.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a method for analyzing optimized operation of a cogeneration unit based on reheat temperature, comprising:

[0007] Acquire multiple target operating conditions of the cogeneration unit; determine an energy consumption fitting formula based on load data and energy consumption data under the multiple target operating conditions;

[0008] Obtaining a demand load of the cogeneration unit, and calculating a first operating benefit of the cogeneration unit before operation optimization based on the demand load and the energy consumption fitting formula; and determining a reheat temperature under an operating condition corresponding to the demand load before operation optimization as a first reheat temperature;

[0009] determining a second reheat temperature for operation optimization based on the first reheat temperature; calculating a second operation benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature; the second reheat temperature being lower than the first reheat temperature;

[0010] An operation benefit analysis result is determined based on the first operation benefit and the second operation benefit.

[0011] In conjunction with the first aspect, in some embodiments, the load data includes electricity load data, heating load data, and industrial heat load data; the demand load includes demand electricity load, demand heating load, and demand industrial heat load;

[0012] Determining the energy consumption fitting formula based on the load data and energy consumption data under the multiple target operating conditions includes: fitting the energy consumption of the cogeneration unit using a polynomial based on the electrical load data, the heating heat load data, the industrial heat load data, and the energy consumption data under the multiple target operating conditions to obtain the energy consumption fitting formula;

[0013] The calculating of the first operating benefit of the cogeneration unit before operation optimization based on the demand load and the energy consumption fitting formula includes: determining a fitting value of a first demand energy consumption based on the demand electricity load, the demand heating heat load, the demand industrial heat load and the energy consumption fitting formula; the first demand energy consumption is the energy consumption of the cogeneration unit under the operating conditions corresponding to the demand load before operation optimization; and determining the first operating benefit based on unit electricity price, unit heating heat price, unit industrial heat price, unit coal price, and the fitting values ​​of the demand electricity load, the demand heating heat load, the demand industrial heat load and the first demand energy consumption.

[0014] In combination with the first aspect, in some embodiments, obtaining multiple target operating conditions of the cogeneration unit includes: establishing a first variable operating condition model of the cogeneration unit based on the baseline operating condition of the cogeneration unit; the input variables of the first variable operating condition model include the main steam flow, heating heat load and industrial heat load of the cogeneration unit, and the output variables include the electric load; based on the first variable operating condition model and preset safe operating conditions, determining the multiple target operating conditions.

[0015] In conjunction with the first aspect, in some embodiments, determining the multiple target operating conditions based on the first variable operating condition model and preset safe operating conditions includes:

[0016] Based on the preset value range of the main steam flow, the preset value range of the heating heat load and the preset value range of the industrial heat load, a working condition screening cycle for safe operation of the steam turbine of the cogeneration unit is constructed; wherein, the working condition screening cycle includes an inner cycle, a sub-inner cycle and an outer cycle; the inner cycle is for the industrial heat load to increase from small within its value range, the sub-inner cycle is for the heating heat load to increase from small within its value range, and the outer cycle is for the main steam flow to decrease from large within its value range; the inner cycle and the sub-inner cycle are both provided with the preset safe operation conditions, and the preset safe operation conditions are that the current main steam flow is greater than or equal to the minimum steam volume for cooling the low-pressure cylinder blades of the cogeneration unit, and the industrial extraction steam temperature is within the preset temperature range;

[0017] The plurality of target operating conditions are determined based on the operating condition screening cycle and the first variable operating condition model.

[0018] In conjunction with the first aspect, in some embodiments, determining the reheat temperature under the operating condition corresponding to the demand load before the optimization operation as the first reheat temperature includes:

[0019] If the cogeneration unit is a unit whose reheat temperature varies with operating conditions before operation optimization, the first reheat temperature is calculated based on the demand load and the first variable operating condition model;

[0020] If the cogeneration unit is a unit whose reheat temperature does not change with operating conditions before operation optimization, the first reheat temperature is a preset temperature value.

[0021] In conjunction with the first aspect, in some embodiments, the cogeneration unit includes a steam turbine, and the load of the cogeneration unit includes an electrical load, a heating load, and an industrial heat load; and establishing a first variable operating condition model of the cogeneration unit based on a baseline operating condition of the cogeneration unit includes:

[0022] Determining, based on the operating parameter data in the reference operating condition, fitting relationship expressions of various operating parameters of the cogeneration unit under the variable operating condition, each of which is based on the main steam flow rate;

[0023] The first variable operating condition model is established based on fitting relationships of the multiple operating parameters based on the main steam flow rate and preset unit operating constraints.

[0024] In conjunction with the first aspect, in some embodiments, the demand load includes a demand electricity load, a demand heating load, and a demand industrial heat load; and calculating the second operating benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature includes:

[0025] setting the reheat temperature of the cogeneration unit under various variable operating conditions to be the second reheat temperature, and establishing a second variable operating condition model of the cogeneration unit based on the reference operating condition;

[0026] Calculating a second required energy consumption value based on the second variable operating condition model, the required electrical load, the required heating heat load, and the required industrial heat load; the second required energy consumption is the energy consumption of the cogeneration unit under the operating condition corresponding to the required load after operation optimization;

[0027] The second operating benefit is determined based on the unit electricity price, unit heating price, unit industrial heat price, unit coal price, and the values ​​of the required electricity load, the required heating load, the required industrial heat load and the second required energy consumption.

[0028] In conjunction with the first aspect, in some embodiments, after determining the operation benefit analysis result, the method further includes:

[0029] When the heating heat load is fixed, the operation boundary line of the cogeneration unit before operation optimization is calculated based on the first variable operating condition model; when the heating heat load is fixed, the operation boundary line of the cogeneration unit after operation optimization is calculated based on the second variable operating condition model; wherein, the operation boundary lines include the pure condensing condition operation boundary line, the maximum main steam flow operation boundary line, the minimum main steam flow operation boundary line and the low-pressure cylinder minimum condensate amount line; the pure condensing condition operation boundary line is the industrial heat load-electric load curve when the industrial heat load is 0, the maximum main steam flow operation boundary line is the industrial heat load-electric load curve when the main steam flow is at its maximum value, the minimum main steam flow operation boundary line is the industrial heat load-electric load curve when the main steam flow is at its minimum value, and the low-pressure cylinder minimum condensate amount line is the industrial heat load-electric load curve when the industrial heat load is at its maximum value;

[0030] Based on the operation boundary lines of the cogeneration unit before and after the operation optimization, the unit flexibility of the cogeneration unit before and after the operation optimization is compared to determine the unit flexibility analysis result.

[0031] In conjunction with the first aspect, in some embodiments, calculating the operating boundary line of the cogeneration unit before operation optimization based on the first variable operating condition model when the heating heat load is fixed includes:

[0032] Setting the heating heat load to a preset reference value;

[0033] When the industrial heat load is 0, the value of the electric load is calculated by the first variable operating condition model according to the value range of the main steam flow rate, to obtain the pure condensing operating condition operating boundary line of the cogeneration unit before operation optimization;

[0034] When the main steam flow rate of the cogeneration unit is at its maximum value, calculating the values ​​of the electric load corresponding to the industrial heat load ranging from 0 to its maximum value through the first variable operating condition model, and obtaining the maximum main steam flow rate operating boundary line of the cogeneration unit before operation optimization;

[0035] When the main steam flow rate of the cogeneration unit is set to its minimum value, the first variable operating condition model is used to calculate the corresponding values ​​of the electric load within the range of the industrial heat load from 0 to its maximum value, thereby obtaining the minimum main steam flow rate operating boundary line of the cogeneration unit before operation optimization;

[0036] When the industrial heat load is at its maximum value, the value of the electric load is calculated using the first variable operating condition model according to the value range of the main steam flow rate, to obtain the minimum condensate volume line of the low-pressure cylinder of the cogeneration unit before operation optimization;

[0037] Based on the pure condensing condition operating boundary line, maximum main steam flow operating boundary line, minimum main steam flow operating boundary line and low-pressure cylinder minimum condensing steam volume line of the cogeneration unit before operation optimization, the operating boundary line of the cogeneration unit before operation optimization is obtained.

[0038] In a second aspect, an embodiment of the present invention provides a device for analyzing optimized operation of a cogeneration unit based on reheat temperature, comprising:

[0039] An energy consumption fitting module is used to obtain multiple target operating conditions of the cogeneration unit; based on the load data and energy consumption data under the multiple target operating conditions, determine an energy consumption fitting formula;

[0040] a first calculation module configured to obtain a demand load of the cogeneration unit, calculate a first operating benefit of the cogeneration unit before operation optimization based on the demand load and the energy consumption fitting formula, and determine a reheat temperature under an operating condition corresponding to the demand load before operation optimization as a first reheat temperature;

[0041] a second calculation module, configured to determine a second reheat temperature for operation optimization based on the first reheat temperature; and calculate a second operation benefit of the cogeneration unit after the operation optimization based on the demand load and the second reheat temperature; wherein the second reheat temperature is lower than the first reheat temperature;

[0042] The benefit analysis module is used to determine an operation benefit analysis result based on the first operation benefit and the second operation benefit.

[0043] An embodiment of the present invention provides a method and device for analyzing the optimized operation of a cogeneration unit based on reheat temperature. The method and device obtain multiple target operating conditions of the cogeneration unit and determine an energy consumption fitting formula based on load data and energy consumption data under the multiple target operating conditions; obtain the required load of the cogeneration unit, and calculate the first operating benefit of the cogeneration unit before operation optimization based on the required load and the energy consumption fitting formula; and determine the reheat temperature under the operating condition corresponding to the required load before operation optimization as the first reheat temperature; based on the first reheat temperature, determine the second reheat temperature for operation optimization; based on the required load and the second reheat temperature, calculate the second operating benefit of the cogeneration unit after operation optimization; the second reheat temperature is less than the first reheat temperature; based on the first operating benefit and the second operating benefit, determine the operating benefit analysis result, thereby realizing efficient analysis of the operation optimization of the unit. In an embodiment of the present invention, based on a certain number of target operating conditions, an energy consumption fitting formula is obtained through fitting, so that the energy consumption data under the corresponding operating condition can be quickly determined based on the load data under other operating conditions. For the unit before operation optimization, the amount of calculation of the variable operating condition during each analysis can be saved, thereby simplifying the calculation process of the operating benefit before the unit operation optimization. In addition, the present invention optimizes the steam supply operation mode of the unit by lowering the reheat temperature. Therefore, the reheat temperature before the unit operation optimization is first determined, and then the operating benefit after the unit operation optimization is calculated based on a second reheat temperature lower than the reheat temperature, so that the operating benefit before and after the unit operation optimization can be compared and analyzed in a targeted manner. Furthermore, the present invention can achieve efficient and accurate unit operation analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0045] Figure 1 Schematic diagram showing the variation of extraction steam temperature with industrial heat load and reheat temperature according to one embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of an application scenario of a method for analyzing the optimized operation of a cogeneration unit based on reheat temperature provided by an embodiment of the present invention;

[0047] Figure 31 is a flow chart of a method for analyzing the optimized operation of a cogeneration unit based on reheat temperature provided by one embodiment of the present invention;

[0048] Figure 4 1 is a flow chart of variable operating condition calculation provided by one embodiment of the present invention;

[0049] Figure 5 1 is a flow chart of a method for analyzing the optimized operation of a cogeneration unit based on reheat temperature provided by another embodiment of the present invention;

[0050] Figure 6 This is a diagram illustrating the electric and thermal operation domain of a cogeneration unit before operation optimization provided by an embodiment of the present invention;

[0051] Figure 7 This is a diagram illustrating the electric and thermal operation domain of a cogeneration unit after operation optimization provided by an embodiment of the present invention;

[0052] Figure 8 It is a structural schematic diagram of a device for optimizing the operation of a cogeneration unit based on reheat temperature provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0053] In the following description, specific details such as particular system structures and techniques are provided for purposes of illustration, not limitation, to facilitate a thorough understanding of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0054] In addition, in the description of the present specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0055] The method and device for analyzing the optimized operation of a cogeneration unit based on the reheat temperature provided in the embodiment of the present invention are designed by the inventor of the present invention based on the optimization means of reducing the reheat temperature of the unit when studying how to reduce the industrial extraction temperature. The inventor found that when extracting steam from the intermediate pressure cylinder to supply industrial steam, the industrial extraction temperature of the unit will be limited by the allowable temperature of the pipeline. When a rotating baffle is used for throttling under low load of the unit, the pressure difference between the extraction steam and the reheat steam is reduced, and the steam work process can be regarded as isentropic work, which will cause the temperature difference to decrease, so that the industrial extraction temperature exceeds the limit. Based on this, the inventor proposed a steam supply operation optimization means to reduce the extraction temperature by reducing the reheat temperature of the unit, and verified through variable operating condition calculations that reducing the reheat temperature can indeed achieve the effect of reducing the extraction temperature, see. Figure 1The discrete curves shown in the figure show how the extraction temperature changes with industrial heat load at different reheat temperatures, decreasing from 530°C to 510°C when the unit's electrical load is 165MW and the heating load is 500GJ·h-1. It can be seen that the extraction temperature (industrial extraction temperature) gradually decreases with increasing industrial heat load, and the extraction temperature (industrial extraction temperature) decreases with decreasing reheat temperature. However, lowering the reheat temperature also affects the unit's operating efficiency and flexibility. Therefore, a comprehensive analysis of the unit's thermal economy and flexibility after lowering the reheat temperature is required. Furthermore, if a comparative analysis of as many operating conditions as possible before and after optimization is to be conducted, a large amount of calculations will be involved, resulting in low analysis efficiency.

[0056] Based on the above problems, the method and device for optimizing the operation analysis of a cogeneration unit based on reheat temperature in the embodiment of the present invention first obtains an energy consumption fitting formula based on a certain number of target operating conditions through fitting, so that the energy consumption data under the corresponding operating conditions can be quickly determined based on the load data under other operating conditions. For the unit before operation optimization, the amount of calculation of the variable operating conditions during each analysis can be saved, thereby simplifying the calculation process of the operating benefits before the unit operation optimization. Secondly, the present invention optimizes the steam supply operation mode of the unit by lowering the reheat temperature. Therefore, the reheat temperature before the unit operation optimization is first determined, and then the operating benefits after the unit operation optimization are calculated based on the second reheat temperature lower than the reheat temperature, so that the operating benefits before and after the unit operation optimization can be targeted and compared. Therefore, the present invention can achieve efficient and accurate unit operation analysis.

[0057] For example, the embodiment of the present invention can be applied to Figure 2 In the exemplary scenario shown. In this scenario, the cogeneration unit 200 (hereinafter referred to as unit 200) includes a boiler 210, a high-pressure cylinder 220, an intermediate-pressure cylinder 230 and a low-pressure cylinder 240. After the unit 200 is running to produce power, the intermediate-pressure cylinder 230 can be subjected to industrial steam extraction and heating steam extraction to achieve industrial heating and heating. When the unit 200 is running, the boiler 210 generates steam by heating water. The steam is first transmitted to the high-pressure cylinder 220 for heating, and then transmitted back from the high-pressure cylinder 220 to the boiler 210 for further heating, and then transmitted to the intermediate-pressure cylinder 230. The intermediate-pressure cylinder 230 performs industrial steam extraction and heating steam extraction. At the same time, the intermediate-pressure cylinder 230 transmits a portion of steam to the low-pressure cylinder 240 for power generation. The above-mentioned cogeneration unit 200 can be a double-extraction unit.

[0058] In the above exemplary scenario, cogeneration unit 200 is a cogeneration unit for industrial steam supply at a power plant. It can generate industrial steam to provide heat for industrial production, generate heating steam to provide heat for heating equipment, and provide electricity. For cogeneration unit 200 in the above scenario, the power plant where it is located can obtain the local demand heating heat load and demand industrial heat load, and can also obtain the demand electricity load of unit 200. If the steam supply operation mode of unit 200 is to be optimized by lowering the reheat temperature, it is necessary to analyze the operating efficiency of unit 200 based on the various demand loads known by the power plant, so as to reasonably determine whether to use this optimization method of reducing the industrial extraction steam temperature by lowering the reheat temperature.

[0059] Figure 3 This is a flow chart of a method for analyzing the optimized operation of a cogeneration unit based on reheat temperature according to an embodiment of the present invention. Figure 3 The detailed description of the optimized operation analysis method of the cogeneration unit based on reheat temperature is as follows:

[0060] S101, obtaining multiple target operating conditions of the cogeneration unit; and determining an energy consumption fitting formula based on load data and energy consumption data under the multiple target operating conditions.

[0061] The target operating conditions described above may refer to variable operating conditions for the safe operation of a cogeneration unit of the same type and under the same baseline operating conditions as the aforementioned cogeneration unit. Each target operating condition includes data on the unit's operating parameters under that condition. For example, the unit operating parameter data may include temperature and pressure data for various components of the unit; further data may include stage efficiency, mechanical efficiency, power generation efficiency, main steam flow, heating heat load, industrial heat load, and energy consumption.

[0062] In the embodiment of the present invention, the load data includes electricity load data, heating load data, and industrial load data. The energy consumption data includes the total coal consumption of the cogeneration unit under various target operating conditions.

[0063] S102, obtaining the demand load of the cogeneration unit, and calculating the first operating benefit of the cogeneration unit before operation optimization based on the demand load and the energy consumption fitting formula; and determining the reheat temperature under the operating conditions corresponding to the demand load before operation optimization as the first reheat temperature.

[0064] In this embodiment of the present invention, the demand load includes the demanded electrical load, the demanded heating load, and the demanded industrial heat load. The reheat temperature, also known as the reheat steam temperature, refers to the steam temperature at the reheat valve inlet. The steam that passes through the reheat valve and enters the reheater is reheat steam.

[0065] S103, based on the first reheat temperature, determining a second reheat temperature for operation optimization; based on the demand load and the second reheat temperature, calculating a second operation benefit of the cogeneration unit after operation optimization; the second reheat temperature is lower than the first reheat temperature.

[0066] In this embodiment of the present invention, a second reheat temperature is determined based on the first reheat temperature, and the second reheat temperature is lower than the first reheat temperature. In other words, the aforementioned operation optimization involves lowering the reheat temperature to optimize the unit's steam supply operation mode. The operation benefit is calculated for the situation after the reheat temperature is lowered, i.e., the operation benefit after the operation optimization is calculated. It should be understood that the "before operation optimization" described in step S102 refers to the situation before the reheat temperature is lowered (i.e., the original steam supply operation mode).

[0067] S104: Determine an operation benefit analysis result based on the first operation benefit and the second operation benefit.

[0068] The method for analyzing the optimized operation of a cogeneration unit based on reheat temperature in the above embodiment optimizes the steam supply operation mode of the unit by lowering the reheat temperature, and calculates the operating efficiency of the unit before and after the operation optimization, thereby analyzing the impact of lowering the reheat temperature on the operating efficiency of the unit and making reasonable use of this operation optimization method.

[0069] Next, the embodiments of the present invention provide some specific implementations of the above steps S101 to S104 to better illustrate the method for analyzing the optimized operation of a cogeneration unit based on reheat temperature provided by the present invention.

[0070] In some embodiments, the implementation method of determining the energy consumption fitting formula based on the load data and energy consumption data under multiple target operating conditions in the above-mentioned step S101 can be: based on the electricity load data, heating heat load data, industrial heat load data and energy consumption data under multiple target operating conditions, the energy consumption of the cogeneration unit is fitted by a polynomial to obtain the energy consumption fitting formula.

[0071] Accordingly, the process of calculating the first operating benefit of the cogeneration unit before operation optimization based on the demand load and energy consumption fitting formula in step S102 may include steps S201 to S202:

[0072] S201, based on the demanded electricity load, the demanded heating heat load, the demanded industrial heat load and the energy consumption fitting formula, determine a fitting value of a first demanded energy consumption; the first demanded energy consumption is the energy consumption of the cogeneration unit under the operating conditions corresponding to the demanded load before operation optimization.

[0073] S202 , determining a first operating benefit based on the unit electricity price, the unit heating price, the unit industrial heat price, the unit coal price, and the fitted values ​​of the required electricity load, the required heating load, the required industrial heat load, and the first required energy consumption.

[0074] In the above embodiment, the energy consumption fitting formula, i.e. the relationship between the energy input and energy output of the cogeneration unit, can be expressed as B=f1(Pe,Qh1,Qh2); wherein B represents the energy consumption of the unit / t·h -1 , Pe represents the electric load / MW, Qh1 represents the heating heat load / GJ / h, and Qh2 represents the industrial heat load / GJ / h; the function f1 can be obtained by fitting the energy consumption using a cubic polynomial or a quartic polynomial.

[0075] For example, it can be expressed by the polynomial s=(a×x+b×y+c×z+d) 3 Energy consumption is fitted. The x, y, z, and s in the polynomial can represent the above-mentioned electric load Pe, heating heat load Qh1, industrial heat load Qh2, and energy consumption B respectively; a, b, and c are the fitting coefficients of each independent variable respectively, and d is a constant.

[0076] In one possible implementation, the load data and energy consumption data for the target operating condition acquired in step S101 are both in the form of three-dimensional matrices. Accordingly, the energy consumption fitting process can be a three-dimensional polynomial fitting based on the least squares method. It should be understood that before fitting, the input variables (electric load Pe, heating heat load Qh1, industrial heat load Qh2) and the output variable (energy consumption B) must be scaled to the same order of magnitude.

[0077] In the embodiment of the present invention, the calculation formula of the operating efficiency of the cogeneration unit is as follows:

[0078] W ope =Ee×Pe+Eq1×Qh1+Eq1×Qh2-B×C0

[0079] Among them, W ope Unit operation efficiency / CNY·h -1 , Ee is the unit electricity price / CNY·(MW·h) -1 , Eq1 is the unit heating price / CNY·GJ -1 , Eq2 is the unit industrial heat price / CNY·GJ -1 , B is the total coal consumption (i.e. energy consumption) of the unit / t·h -1 , C0 is the unit coal price / CNY·t -1 .

[0080] It can be seen that when the demand load is known, the difference in operating efficiency before and after unit optimization lies solely in the difference in energy consumption. When calculating the first operating efficiency, the energy consumption B is the fitted value calculated using the above energy consumption fitting formula. When calculating the second operating efficiency, the energy consumption B should be the energy consumption value calculated for the operating conditions corresponding to the current demand load after unit optimization.

[0081] In some embodiments, obtaining multiple target operating conditions of the cogeneration unit in step S101 can be achieved through steps S301 to S302:

[0082] S301, based on the baseline operating condition of the cogeneration unit, establish a first variable operating condition model of the cogeneration unit; the input variables of the first variable operating condition model include the main steam flow, heating heat load and industrial heat load of the cogeneration unit, and the output variables include the electricity load.

[0083] The baseline operating conditions for the aforementioned cogeneration units can be obtained from the unit's heat balance diagram, field operating data, or experimental data. The baseline operating conditions include data on various parameters such as turbine stage efficiency, cylinder efficiency, steam temperature, steam pressure, steam flow, and condensate flow.

[0084] S302 : Determine multiple target operating conditions based on the first variable operating condition model and preset safe operating conditions.

[0085] In the above embodiment, the first variable operating condition model can be determined using a variable operating condition calculation method commonly used in the art, or can be an existing variable operating condition model in the art. It should be noted that if an existing variable operating condition model is directly used, it is necessary to select a variable operating condition model for a unit of the same type as the cogeneration unit to be analyzed and with exactly the same baseline operating conditions.

[0086] The first variable operating condition model can be expressed as [Pe, Ddyr, tx, px, B] = f2(D0, Qh1, Qh2). Here, D0 is the main steam flow rate, Ddyr is the steam flow rate in the low-pressure cylinder of the turbine inlet (t / h), tx is the extraction temperature (°C), and px is the extraction pressure (MPa). This first variable operating condition model takes as input the main steam flow rate D0, the heating heat load Qh1, and the industrial heat load Qh2, and outputs the electrical load Pe. It also returns the values ​​of the low-pressure cylinder steam flow rate Ddyr, the industrial extraction temperature tx, the industrial extraction pressure px, and the energy consumption B.

[0087] In one possible implementation, the implementation of step S301 may include: determining, based on the operating parameter data in the baseline operating condition, the fitting relationship between the various operating parameters of the cogeneration unit under the variable operating condition and the main steam flow; and establishing a first variable operating condition model based on the fitting relationship between the various operating parameters and the main steam flow and the preset unit operating constraints.

[0088] The above-mentioned preset unit operation constraints, i.e., the basic operating constraints of the electricity and heat load supplied by the cogeneration unit, may include:

[0089] a) The amount of new steam is less than the maximum continuous evaporation capacity of the boiler;

[0090] b) The steam inlet to the low-pressure cylinder is greater than the minimum condensing steam flow rate of the low-pressure cylinder;

[0091] c) The electrical load of the unit is greater than the electrical load of the boiler under stable combustion conditions.

[0092] It can be understood that the first variable operating condition model is integrated based on the calculation process of the variable operating condition. The following provides a calculation process of the variable operating condition:

[0093] First, the turbine stage efficiency or cylinder efficiency under known baseline operating conditions is calculated and the discrete efficiency values ​​are fitted based on the main steam flow rate D0 for iterative calculations under variable operating conditions. Next, parameters such as the main steam temperature and pressure, reheat steam temperature and pressure, feedwater pump power, and small turbine efficiency are selected for fitting. All of these parameters can be fitted based on the main steam flow rate D0.

[0094] The fitting polynomial of the above parameters can be:

[0095] y=a0+a1×x+a2×x 2

[0096] Among them, x can represent the main steam flow rate D0, y can represent the above parameters; a0, a1, and a2 are the constant term, the first-order coefficient, and the second-order coefficient, respectively.

[0097] Then, the values ​​of the electric load, heating heat load and industrial heat load are given respectively, and the initial value of the main steam flow is set. Based on the fitting formulas of the stage efficiency, cylinder efficiency, mechanical efficiency, power generation efficiency and various other parameters, the variable operating conditions of the cogeneration unit are calculated, and the calculated value of the main steam flow is back-calculated according to the calculation results of the variable operating conditions. Based on the calculated value, initial value and preset accuracy value of the main steam flow, it is judged whether the main steam flow under the current variable operating conditions converges. If not, the initial value of the main steam flow is updated, and the variable operating conditions are iteratively calculated until the main steam flow converges.

[0098] The calculation process of the above-mentioned calculated value of the main steam flow rate may include: dividing the steam turbine into three components: from the regulating stage to the heating extraction port, from the heating extraction port to the industrial extraction port, and from the industrial extraction port to the condenser, using the Flügel formula to determine the extraction pressure of each stage of the steam turbine, determining the extraction share of each stage of the regenerative heater, calculating the unit new steam work, and finally combining the given electrical load, mechanical efficiency, and power generation efficiency to calculate the new main steam flow rate value and the calculated value of the main steam flow rate.

[0099] Finally, after the variable operating condition calculation is completed, the steam-water parameters at each location of the steam turbine can be obtained, and then the energy consumption can be calculated as needed.

[0100] See also Figure 4 The calculation process of variable working conditions includes: first input the electrical and thermal loads Pe and Qh2 of the variable working conditions, and then calculate the level efficiency η from the reference working condition (known working condition in the figure). i(r) ; Then give the initial value of the main steam flow, and then calculate the extraction pressure, extraction share, and unit new steam work; then, calculate the new main steam flow (new steam volume in the figure); then, determine whether the difference between the new main steam flow and the initial value is less than or equal to the preset accuracy value. If not, adjust the initial value of the main steam flow, and then jump to the step of calculating the extraction pressure, and iterate continuously until the difference between the new main steam flow and the initial value is less than or equal to the preset accuracy value. At this time, no more iteration is performed, and the energy consumption of the unit can be calculated.

[0101] The above stage efficiency η i(r) The calculation formula is:

[0102]

[0103] Among them, h 1(r) is the inlet steam enthalpy of the r-stage group, in kJ·kg -1 ;h 2(r) is the outlet steam enthalpy of the r-stage group, in kJ·kg -1 ;H s(r) is the isentropic expansion enthalpy drop of the r-stage steam in the turbine, in kJ·kg -1 .

[0104] The main steam flow rate D in the first iteration above s The calculation formula is:

[0105]

[0106] Where Pe is the unit electrical load, MW; Pe0 represents the given value of the unit electrical load under variable operating conditions; D s0 Indicates the initial value of the given main steam flow under variable operating conditions.

[0107] The above extraction steam pressure P r The calculation formula is:

[0108]

[0109] Among them, P r 、P r+1 is the extraction steam pressure of the rth and r+1th stages, MPa; D r is the steam flow rate of the r-stage group, in t·h -1; The symbol with the subscript 0 indicates the previous iteration value of the corresponding parameter. In the first iteration, the symbol with the subscript 0 indicates the given value of the corresponding parameter.

[0110] The above extraction steam share α j The calculation formula is:

[0111]

[0112] Among them, α j is the extraction steam share, that is, the extraction coefficient of the heater; α H is the outlet water share of heater No.j; β j is the drain fraction flowing into No.j heater; q fj is the additional heat entering the No. j heater, in kJ·kg -1 .

[0113] The calculation formula for the above unit new steam work is:

[0114] H0=(h0-h n +σ zr )-∑α j Δh j -∑α fj Δh fj

[0115] The unit of H0 is kJ·kg -1 ; h0 is the main steam enthalpy, kJ·kg -1 ;h n is the exhaust enthalpy of the low-pressure cylinder of the steam turbine, kJ·kg -1 ; σ zr is the heat absorbed by the reheated steam in the reheater, kJ·kg -1 ; Δh j is the minimum work done by the steam extracted from the No. j heater in the turbine, kJ·kg -1 ; α fj is the auxiliary steam share; Δh fj is α fj Minimum work done by auxiliary steam in the turbine, kJ·kg -1 .

[0116] The new main steam flow D s1 The calculation formula is:

[0117]

[0118] Among them, η m ,η g It is the mechanical efficiency and power generation efficiency of the steam turbine unit.

[0119] The convergence condition of the above variable working condition iteration is:

[0120] D s1 -D s ≤ε

[0121] Among them, ε is the preset accuracy value.

[0122] In one possible implementation, step S302 can be implemented as follows: First, based on a preset range of values ​​for the main steam flow rate D0, a preset range of values ​​for the heating heat load Qh1, and a preset range of values ​​for the industrial heat load Qh2, a condition screening cycle for safe operation of the steam turbine of the cogeneration unit is constructed. The condition screening cycle includes an inner cycle, a sub-inner cycle, and an outer cycle. The inner cycle is for the industrial heat load Qh2 to increase from a small value within its value range (from 0 to its maximum value), the sub-inner cycle is for the heating heat load Qh1 to increase from a small value within its value range (from 0 to its maximum value), and the outer cycle is for the main steam flow rate D0 to decrease from a large value within its value range. Both the inner cycle and the sub-inner cycle are provided with preset safe operating conditions, wherein the preset safe operating conditions are that the current main steam flow rate D0 is greater than or equal to the minimum steam flow for cooling the low-pressure cylinder blades of the cogeneration unit, and that the industrial extraction steam temperature is within a preset temperature range. Then, based on the condition screening cycle and the first variable operating condition model, multiple target operating conditions are determined.

[0123] In the above embodiment, each cycle takes values ​​according to a specific step size. For example, the range of the industrial heat load Qh2 in the inner cycle is 0 to 20, and the cycle step size is 2. This means that the calculation and screening are performed for industrial heat load Qh2 values ​​of 0, 2, 4, ..., and 20, respectively. The step sizes of each cycle can be the same or different, and this is not limited in the present invention.

[0124] In the above embodiment, during the screening process of the inner layer circulation and the sub-inner layer circulation, if either the main steam flow rate D0 or the industrial extraction steam temperature does not meet the above preset safe operation conditions, the current circulation is exited.

[0125] In the actual cycle program, the inner loop can be recorded as the k-layer, the sub-inner loop as the j-layer, and the outer loop as the i-layer. The electric load, heating heat load, industrial heat load, and energy consumption obtained through the above-mentioned working condition screening cycle can be recorded using the three-dimensional matrix x(i,j,k), y(i,j,k), z(i,j,k), and s(i,j,k), thereby obtaining the load data and energy consumption data under the above-mentioned multiple target working conditions. It can be understood that the data of the first face (1,j,k) of the three-dimensional matrix corresponds to the electric load, heating heat load, industrial heat load, and energy consumption under the maximum main steam flow rate, the other faces correspond to the electric load, heating heat load, industrial heat load, and energy consumption when the main steam flow rate is other values, and the last face corresponds to the electric load, heating heat load, industrial heat load, and energy consumption under the minimum main steam flow rate. Recording load data and energy consumption data through a three-dimensional matrix facilitates the representation of large amounts of data.

[0126] In some embodiments, there are two ways to determine the first reheat temperature in step S102, each determined based on the actual situation of the cogeneration unit to be analyzed: First, if the cogeneration unit, before operation optimization, has a reheat temperature that varies with operating conditions, then the first reheat temperature is calculated based on the demand load and a first variable operating condition model. Second, if the cogeneration unit, before operation optimization, has a reheat temperature that does not vary with operating conditions, then the first reheat temperature is a preset temperature value.

[0127] In the first approach, the unit's reheat temperature varies with operating conditions. Therefore, the actual reheat temperature value for the current operating condition must be derived based on the demand load and the first variable operating condition model. In the second approach, the unit's reheat temperature remains constant. In the first variable operating condition model, the reheat temperature is actually a preset value. Therefore, only this preset value is required, eliminating the need for calculation.

[0128] It should be noted that for the unit in the first method described above, before the reheat temperature is lowered, when calculating the unit's variable operating conditions (or when establishing the first variable operating condition model), the reheat temperature is fitted by the main steam flow rate. Changes in the main steam flow rate will cause changes in the reheat temperature. After the reheat temperature is lowered (after operation optimization), the reheat temperature parameter no longer changes with changes in operating conditions. The actual unit can maintain the lowered reheat temperature. Therefore, when calculating the unit's operating conditions after operation optimization, the reheat temperature must be set to a fixed value. For actual unit equipment, the reheat temperature of the unit before operation optimization will not be controlled by external factors. However, after operation optimization, a cooling device can be installed in the unit's reheater to keep the reheat temperature constant at the second reheat temperature. In summary, for the units in the first mode, the difference in operating conditions before and after operation optimization is mainly whether the reheat temperature changes with the operating conditions. This difference will affect the overall operating conditions of the unit, thereby affecting the energy consumption of the unit and bringing about different operating benefits.

[0129] For the units in the second method described above, the reheat temperature is fixed before and after the optimization. The difference is that the reheat temperature set after the optimization is lower than the reheat temperature set before the optimization. Different reheat temperatures result in different energy consumption and operational benefits.

[0130] In some embodiments, determining the second reheat temperature for operation optimization based on the first reheat temperature in step S103 may be implemented by subtracting the first reheat temperature from a preset temperature difference to obtain the second reheat temperature.

[0131] In some embodiments, calculating the second operating benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature in step S103 can be achieved through steps S401 to S403:

[0132] S401 , setting the reheat temperature of the cogeneration unit under various variable operating conditions to be the second reheat temperature, and establishing a second variable operating condition model of the cogeneration unit based on the reference operating condition.

[0133] S402, based on the second variable operating condition model, the demanded electrical load, the demanded heating load, and the demanded industrial heat load, calculate the value of the second demanded energy consumption; the second demanded energy consumption is the energy consumption of the cogeneration unit under the operating condition corresponding to the demanded load after operation optimization.

[0134] In a possible implementation, the calculation formula for the second required energy consumption is:

[0135] Q b =D0(h0-h fw )+Drh (h rh,out -h rh,in )

[0136]

[0137] Among them, Q b Absorbs heat for the boiler; B zr is the second required energy consumption; D0 is the main steam flow rate; h0 is the main steam enthalpy value, unit is kJ / kg; h fw is the feed water enthalpy value, in kJ / kg; D rh is the reheat steam volume, in kg / h; rh,out is the enthalpy of steam after reheating, in kJ / kg; h rh,in is the steam enthalpy before reheating, in kJ / kg; η b is the boiler efficiency; η p is the pipeline efficiency; LHV is the lower heating value of coal.

[0138] S403 , determining a second operating benefit based on the unit electricity price, the unit heating price, the unit industrial heat price, the unit coal price, and the values ​​of the required electricity load, the required heating load, the required industrial heat load, and the second required energy consumption.

[0139] If the cogeneration unit being analyzed has a reheat temperature that varies with operating conditions, the second variable operating condition model in the above embodiment differs from the first variable operating condition model only in how the reheat temperature is determined. Specifically, in the first variable operating condition model, the reheat temperature is a fitted equation based on the main steam flow rate, while in the second variable operating condition model, the reheat temperature is a constant value.

[0140] If the cogeneration unit to be analyzed is a unit whose reheat temperature does not change with the operating conditions, the difference between the second variable operating condition model and the first variable operating condition model in the above embodiment is only the different set values ​​of the reheat temperature, that is, the reheat temperature in the second variable operating condition model is lower than the reheat temperature in the first variable operating condition model.

[0141] In some embodiments, step S104 may include:

[0142] The benefit difference between the second operating benefit and the first operating benefit is calculated. If the benefit difference is greater than a preset threshold, the operating benefit after the operation optimization is determined to be excellent. If the benefit difference is less than or equal to the preset threshold, the operating benefit after the operation optimization is determined to be poor. The preset threshold is greater than or equal to 0. If the operating benefit after the operation optimization is excellent, a prompt may be issued to recommend that the operation optimization method of lowering the reheat temperature be adopted. Conversely, if the operating benefit after the operation optimization is poor, a prompt may be issued to advise against adopting the operation optimization method of lowering the reheat temperature.

[0143] In the above embodiment, the calculation formula of the benefit difference is as follows:

[0144] ΔW=W ope2 -W ope1

[0145] Among them, ΔW is the above benefit difference / CNY·h -1 ,Subscripts '1' and '2' respectively represent the ,before and after the optimization run.

[0146] Table 1 is a comparison table of operating benefits under typical heating conditions provided by an embodiment of the present invention. See Table 1, where the "operating economic benefit difference" column is the above-mentioned benefit difference. According to Table 1, it can be seen that when the heating heat load is 500GJ / h, the operating economic benefit difference is greater than 0, that is, lowering the reheat temperature operation can improve the operating benefit of the unit; when the heating heat load is 100GJ / h, the operating benefit difference is less than 0, and lowering the reheat temperature operation is not conducive to improving the operating benefit of the unit. When the heating heat load is 500GJ / h, as the industrial heat load increases, the operating benefit difference also increases. Therefore, it can be seen that when the heating heat load is low, the method of lowering the reheat temperature operation is not conducive to the economic benefit of the unit, and as the two heat loads, industrial heat load and heating heat load, increase, lowering the reheat temperature operation will gradually increase the economic benefit of the unit.

[0147] Table 1 Comparison of operating benefits under typical heating conditions

[0148]

[0149] In some embodiments, see Figure 5 After step S104, the combined heat and power unit optimization operation analysis method based on reheat temperature provided by the present invention may further include steps S105 and S107:

[0150] S105 , when the heating heat load is fixed, the operation boundary line of the cogeneration unit before operation optimization is calculated based on the first variable operating condition model.

[0151] S106 , when the heating heat load is fixed, based on the second variable operating condition model, calculating the operating boundary line of the cogeneration unit after the operation optimization.

[0152] Among them, the operating boundary lines include the pure condensing condition operating boundary line, the maximum main steam flow operating boundary line, the minimum main steam flow operating boundary line and the low-pressure cylinder minimum condensate quantity line; the pure condensing condition operating boundary line is the industrial heat load-electric load curve when the industrial heat load is 0, the maximum main steam flow operating boundary line is the industrial heat load-electric load curve when the main steam flow is its maximum value, the minimum main steam flow operating boundary line is the industrial heat load-electric load curve when the main steam flow is its minimum value, and the low-pressure cylinder minimum condensate quantity line is the industrial heat load-electric load curve when the industrial heat load is its maximum value.

[0153] S107 , based on the operation boundary lines of the cogeneration unit before and after the operation optimization, compare the unit flexibility of the cogeneration unit before and after the operation optimization to determine a unit flexibility analysis result.

[0154] In the above embodiment, the implementation process of step S106 may include the following steps:

[0155] Step 1: Set the heating heat load to a preset reference value; for example, set j=1.

[0156] Step 2: When the industrial heat load Qh2 is 0, the value of the electric load is calculated through the first variable operating condition model according to the value range of the main steam flow, and the pure condensing operating condition operating boundary line corresponding to the cogeneration unit (Qh2, Pe) before operation optimization is obtained.

[0157] Step 3. When the main steam flow rate D0 of the cogeneration unit is at its maximum value, the first variable operating condition model is used to calculate the value of the electric load corresponding to the industrial heat load ranging from 0 to its maximum value, and the maximum main steam flow operating boundary line corresponding to the cogeneration unit (Qh2, Pe) before operation optimization is obtained.

[0158] Step 4. When the main steam flow rate D0 of the cogeneration unit is set to its minimum value, the first variable operating condition model is used to calculate the value of the electric load corresponding to the industrial heat load ranging from 0 to its maximum value, and the minimum main steam flow operating boundary line corresponding to the cogeneration unit (Qh2, Pe) before operation optimization is obtained.

[0159] Step 5: When the industrial heat load Qh2 reaches its maximum value, the value of the electric load is calculated through the first variable operating condition model according to the value range of the main steam flow rate D0, and the low-pressure cylinder minimum condensate line corresponding to (Qh2, Pe) of the cogeneration unit before operation optimization is obtained.

[0160] When implementing step 5 through a computer program, the above-mentioned operating condition screening cycle can be used. In order to obtain the minimum condensate line of the low-pressure cylinder, a new matrix A(k,1,3) can be added to the condition judgment of the inner layer cycle to record the electrical load, industrial heat load, and energy consumption when the minimum steam inlet volume of the low-pressure cylinder is reached, that is, the last set of unit parameters before the termination of each main steam flow cycle: A(k,1,1)=x(i,1,k), A(k,1,2)=z(i,1,k), A(k,1,3)=s(i,1,k).

[0161] Step 6: Based on the pure condensing condition operating boundary line, the maximum main steam flow operating boundary line, the minimum main steam flow operating boundary line and the low-pressure cylinder minimum condensing steam volume line of the cogeneration unit before operation optimization, the operating boundary line of the cogeneration unit before operation optimization is obtained.

[0162] Figure 6 and Figure 7 The run boundary lines before and after the run optimization are shown. Figure 6 and Figure 7 Taking a heating load of 500 GJ·h⁻¹ as an example, the original unit's peak-shaving capacity ratio was 29.3%. After optimization, the maximum peak-shaving capacity ratio reached 43.3%, and the minimum peak-shaving capacity ratio was 39.3%, achieved at an industrial heat load of 600 GJ / h. Therefore, lowering the reheat temperature can increase the peak-shaving capacity ratio of the cogeneration unit. Therefore, it can be concluded that lowering the reheat temperature improves unit flexibility.

[0163] The four types of boundary lines included in the above-mentioned operating boundary lines can be found in Figure 6 Among them, A1 is the operating boundary line of pure condensing condition, A2 is the operating boundary line of maximum main steam flow, A3 is the operating boundary line of minimum main steam flow, and A4 is the minimum condensing steam volume line of low-pressure cylinder.

[0164] The method for analyzing the optimized operation of a cogeneration unit based on reheat temperature provided by an embodiment of the present invention can fit the energy consumption and operating boundaries of the unit by screening the safe operating conditions of the unit; by fitting a three-variable cubic polynomial based on the least squares method with three inputs and one output for energy consumption, the calculation process of the unit's variable operating condition cost (energy consumption cost) is greatly simplified; at the same time, the embodiment of the present invention quantitatively calculates the economy and flexibility of the cogeneration unit before and after reducing the reheat temperature, which is of great significance to the optimization of the unit's heating operation.

[0165] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0166] Corresponding to the above embodiment, the combined heat and power unit optimization operation analysis method based on the reheat temperature is described. Figure 8 A structural diagram of a device for optimizing operation and analyzing a cogeneration unit based on reheat temperature provided by an embodiment of the present invention is shown. For ease of description, only parts related to the embodiment of the present invention are shown.

[0167] See also Figure 8 The device 800 for analyzing the optimized operation of a cogeneration unit based on reheat temperature in an embodiment of the present invention may include an energy consumption fitting module 810 , a first calculation module 820 , a second calculation module 830 and a benefit analysis module 840 .

[0168] The energy consumption fitting module 810 can be used to obtain multiple target operating conditions of the cogeneration unit and determine an energy consumption fitting formula based on the load data and energy consumption data under the multiple target operating conditions.

[0169] The first calculation module 820 can be used to obtain the demand load of the cogeneration unit, and calculate the first operating benefit of the cogeneration unit before operation optimization based on the demand load and energy consumption fitting formula; and determine the reheat temperature under the operating conditions corresponding to the demand load before operation optimization as the first reheat temperature.

[0170] The second calculation module 830 can be used to determine a second reheat temperature for operation optimization based on the first reheat temperature; calculate the second operation benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature; the second reheat temperature is lower than the first reheat temperature.

[0171] The benefit analysis module 840 is configured to determine an operation benefit analysis result based on the first operation benefit and the second operation benefit.

[0172] Optionally, the energy consumption fitting module 810 can be specifically used to fit the energy consumption of the cogeneration unit through a polynomial based on the electric load data, heating heat load data, industrial heat load data and energy consumption data under multiple target working conditions to obtain an energy consumption fitting formula.

[0173] Optionally, the energy consumption fitting module 810 can be specifically used to: establish a first variable operating condition model of the cogeneration unit based on the baseline operating condition of the cogeneration unit; the input variables of the first variable operating condition model include the main steam flow, heating heat load and industrial heat load of the cogeneration unit, and the output variables include the electric load; based on the first variable operating condition model and preset safe operating conditions, determine multiple target operating conditions.

[0174] Optionally, the energy consumption fitting module 810 can be specifically used to: construct a working condition screening cycle for safe operation of the steam turbine of the cogeneration unit based on a preset value range of the main steam flow, a preset value range of the heating heat load and a preset value range of the industrial heat load; wherein the screening cycle includes an inner cycle, a sub-inner cycle and an outer cycle; the inner cycle is for the industrial heat load to increase from small within its value range, the sub-inner cycle is for the heating heat load to increase from small within its value range, and the outer cycle is for the main steam flow to decrease from large within its value range; both the inner cycle and the sub-inner cycle are provided with preset safe operating conditions, and the preset safe operating conditions are that the current main steam flow is greater than or equal to the minimum steam volume for cooling the low-pressure cylinder blades of the cogeneration unit, and the industrial extraction steam temperature is within the preset temperature range; based on the working condition screening cycle and the first variable working condition model, multiple target working conditions are determined.

[0175] Optionally, the energy consumption fitting module 810 can be specifically used to: determine the fitting relationship between multiple operating parameters of the cogeneration unit under variable operating conditions based on the main steam flow rate based on the operating parameter data in the baseline operating conditions; establish a first variable operating condition model based on the fitting relationship between multiple operating parameters based on the main steam flow rate and preset unit operating constraints.

[0176] Optionally, the first calculation module 820 can be specifically used to: determine the fitting value of the first demand energy consumption based on the demand electric load, the demand heating heat load, the demand industrial heat load and the energy consumption fitting formula; the first demand energy consumption is the energy consumption of the cogeneration unit under the operating conditions corresponding to the demand load before operation optimization; determine the first operating benefit based on the unit electricity price, unit heating heat price, unit industrial heat price, unit coal price, and the fitting values ​​of the demand electric load, the demand heating heat load, the demand industrial heat load and the first demand energy consumption.

[0177] Optionally, the first calculation module 820 can be specifically used to: if the cogeneration unit is a unit whose reheat temperature changes with the operating conditions before operation optimization, then the first reheat temperature is calculated based on the demand load and the first variable operating condition model; if the cogeneration unit is a unit whose reheat temperature does not change with the operating conditions before operation optimization, then the first reheat temperature is a preset temperature value.

[0178] Optionally, the second calculation module 830 can be specifically used to: make the reheat temperature of the cogeneration unit under various variable operating conditions the second reheat temperature, and establish a second variable operating condition model of the cogeneration unit based on the benchmark operating condition; calculate the value of the second demand energy consumption based on the second variable operating condition model, the demanded electric load, the demanded heating load and the demanded industrial heat load; the second demanded energy consumption is the energy consumption of the cogeneration unit under the operating condition corresponding to the demanded load after operation optimization; determine the second operating benefit based on the unit electricity price, unit heating price, unit industrial heat price, unit coal price, and the values ​​of the demanded electric load, demanded heating load, demanded industrial heat load and the second demanded energy consumption.

[0179] Optionally, the above-mentioned cogeneration unit optimization operation analysis device 800 based on reheat temperature may further include:

[0180] The flexibility analysis module is used to calculate the operating boundary line of the cogeneration unit before operation optimization based on the first variable operating condition model when the heating heat load is fixed; and calculate the operating boundary line of the cogeneration unit after operation optimization based on the second variable operating condition model when the heating heat load is fixed; wherein the operating boundary lines include the pure condensing condition operating boundary line, the maximum main steam flow operating boundary line, the minimum main steam flow operating boundary line and the low-pressure cylinder minimum condensate volume line; the pure condensing condition operating boundary line is the industrial heat load-electric load curve when the industrial heat load is 0, the maximum main steam flow operating boundary line is the industrial heat load-electric load curve when the main steam flow is at its maximum value, the minimum main steam flow operating boundary line is the industrial heat load-electric load curve when the main steam flow is at its minimum value, and the low-pressure cylinder minimum condensate volume line is the industrial heat load-electric load curve when the industrial heat load is at its maximum value; based on the operating boundary lines of the cogeneration unit before and after operation optimization, the unit flexibility of the cogeneration unit before and after operation optimization is compared to determine the unit flexibility analysis result.

[0181] The flexibility analysis module can be used specifically to: set the heating heat load to a preset reference value; when the industrial heat load is 0, according to the value range of the main steam flow, the value of the electric load is calculated through the first variable operating condition model, and the pure condensing condition operation boundary line of the cogeneration unit before operation optimization is obtained; when the main steam flow of the cogeneration unit is at its maximum value, the first variable operating condition model is used to calculate the value of the electric load corresponding to the industrial heat load from 0 to its maximum value, and the maximum main steam flow operation boundary line of the cogeneration unit before operation optimization is obtained; when the main steam flow of the cogeneration unit is set to its minimum value, the first variable operating condition model is used to calculate the value of the electric load corresponding to the industrial heat load from 0 to its maximum value, and the maximum main steam flow operation boundary line of the cogeneration unit before operation optimization is obtained. , calculate the value of the electric load corresponding to the industrial heat load in the range from 0 to its maximum value, and obtain the minimum main steam flow operating boundary line of the cogeneration unit before operation optimization; when the industrial heat load is at its maximum value, according to the value range of the main steam flow, calculate the value of the electric load through the first variable operating condition model, and obtain the minimum condensate amount line of the low-pressure cylinder of the cogeneration unit before operation optimization; based on the pure condensing condition operating boundary line, maximum main steam flow operating boundary line, minimum main steam flow operating boundary line and low-pressure cylinder minimum condensate amount line of the cogeneration unit before operation optimization, the operating boundary line of the cogeneration unit before operation optimization is obtained.

[0182] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0183] Those skilled in the art will appreciate that the templates, units, and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0184] If the module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, it can implement the steps of the above-mentioned embodiments of the combined heat and power unit optimization operation analysis method based on reheat temperature. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium, etc.

[0185] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. A method for analyzing the optimized operation of a cogeneration unit based on reheat temperature, characterized in that: include: Obtain multiple target operating conditions of the cogeneration unit; Determining an energy consumption fitting formula based on the load data and energy consumption data under the multiple target operating conditions; Obtaining a demand load of the cogeneration unit, and calculating a first operating benefit of the cogeneration unit before operation optimization based on the demand load and the energy consumption fitting formula; and determining a reheat temperature under the operating condition corresponding to the demand load before the optimization operation as a first reheat temperature; determining a second reheat temperature for operation optimization based on the first reheat temperature; calculating a second operating benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature; The second reheat temperature is lower than the first reheat temperature; An operation benefit analysis result is determined based on the first operation benefit and the second operation benefit.

2. The method for optimizing the operation of a cogeneration unit based on reheat temperature according to claim 1, characterized in that: The load data includes electric load data, heating load data and industrial heat load data; the demand load includes demand electric load, demand heating load and demand industrial heat load; The determining of the energy consumption fitting formula based on the load data and energy consumption data under the multiple target operating conditions includes: Based on the electric load data, the heating heat load data, the industrial heat load data, and the energy consumption data under the multiple target operating conditions, the energy consumption of the cogeneration unit is fitted using a polynomial to obtain the energy consumption fitting formula; The calculating, based on the demand load and the energy consumption fitting formula, the first operating benefit of the cogeneration unit before operation optimization, includes: Determining a fitting value of a first required energy consumption based on the required electrical load, the required heating load, the required industrial heat load, and the energy consumption fitting formula; the first required energy consumption is the energy consumption of the cogeneration unit under the operating conditions corresponding to the required load before operation optimization; The first operating benefit is determined based on the unit electricity price, the unit heating price, the unit industrial heat price, the unit coal price, and the fitting values ​​of the required electricity load, the required heating load, the required industrial heat load and the first required energy consumption.

3. The method for optimizing the operation of a cogeneration unit based on reheat temperature according to claim 1, wherein: The obtaining of multiple target operating conditions of the cogeneration unit includes: Based on the baseline operating condition of the cogeneration unit, a first variable operating condition model of the cogeneration unit is established; the input variables of the first variable operating condition model include the main steam flow, heating heat load and industrial heat load of the cogeneration unit, and the output variable includes the electricity load; The multiple target operating conditions are determined based on the first variable operating condition model and preset safe operating conditions.

4. The method for optimizing the operation of a cogeneration unit based on reheat temperature according to claim 3, characterized in that: The determining of the plurality of target operating conditions based on the first variable operating condition model and preset safe operating conditions includes: Based on the preset value range of the main steam flow, the preset value range of the heating heat load and the preset value range of the industrial heat load, a working condition screening cycle for safe operation of the steam turbine of the cogeneration unit is constructed; wherein, the working condition screening cycle includes an inner cycle, a sub-inner cycle and an outer cycle; the inner cycle is for the industrial heat load to increase from small within its value range, the sub-inner cycle is for the heating heat load to increase from small within its value range, and the outer cycle is for the main steam flow to decrease from large within its value range; the inner cycle and the sub-inner cycle are both provided with the preset safe operation conditions, and the preset safe operation conditions are that the current main steam flow is greater than or equal to the minimum steam volume for cooling the low-pressure cylinder blades of the cogeneration unit, and the industrial extraction steam temperature is within the preset temperature range; The plurality of target operating conditions are determined based on the operating condition screening cycle and the first variable operating condition model.

5. The method for optimizing the operation of a cogeneration unit based on reheat temperature according to claim 3, characterized in that: The determining, as the first reheat temperature, the reheat temperature under the operating condition corresponding to the demand load before the optimization operation includes: If the cogeneration unit is a unit whose reheat temperature varies with operating conditions before operation optimization, the first reheat temperature is calculated based on the demand load and the first variable operating condition model; If the cogeneration unit is a unit whose reheat temperature does not change with operating conditions before operation optimization, the first reheat temperature is a preset temperature value.

6. The method for optimizing the operation of a cogeneration unit based on reheat temperature according to claim 3, characterized in that: The cogeneration unit includes a steam turbine, and the load of the cogeneration unit includes electrical load, heating load and industrial heat load; The step of establishing a first variable operating condition model of the cogeneration unit based on the baseline operating condition of the cogeneration unit includes: Determining, based on the operating parameter data in the reference operating condition, fitting relationship expressions of various operating parameters of the cogeneration unit under the variable operating condition, each of which is based on the main steam flow rate; The first variable operating condition model is established based on fitting relationships of the multiple operating parameters based on the main steam flow rate and preset unit operating constraints.

7. The method for analyzing the optimized operation of a cogeneration unit based on reheat temperature according to claim 3, characterized in that: The demand load includes demand electricity load, demand heating load and demand industrial heat load; Calculating a second operating benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature includes: setting the reheat temperature of the cogeneration unit under various variable operating conditions to be the second reheat temperature, and establishing a second variable operating condition model of the cogeneration unit based on the reference operating condition; Calculating a second required energy consumption value based on the second variable operating condition model, the required electrical load, the required heating heat load, and the required industrial heat load; the second required energy consumption is the energy consumption of the cogeneration unit under the operating condition corresponding to the required load after operation optimization; The second operating benefit is determined based on the unit electricity price, unit heating price, unit industrial heat price, unit coal price, and the values ​​of the required electricity load, the required heating load, the required industrial heat load and the second required energy consumption.

8. The method for analyzing the optimized operation of a cogeneration unit based on reheat temperature according to claim 7, characterized in that: After determining the operation benefit analysis result, the method further includes: When the heating heat load is fixed, the operation boundary line of the cogeneration unit before operation optimization is calculated based on the first variable operating condition model; when the heating heat load is fixed, the operation boundary line of the cogeneration unit after operation optimization is calculated based on the second variable operating condition model; wherein, the operation boundary lines include the pure condensing condition operation boundary line, the maximum main steam flow operation boundary line, the minimum main steam flow operation boundary line and the low-pressure cylinder minimum condensate amount line; the pure condensing condition operation boundary line is the industrial heat load-electric load curve when the industrial heat load is 0, the maximum main steam flow operation boundary line is the industrial heat load-electric load curve when the main steam flow is at its maximum value, the minimum main steam flow operation boundary line is the industrial heat load-electric load curve when the main steam flow is at its minimum value, and the low-pressure cylinder minimum condensate amount line is the industrial heat load-electric load curve when the industrial heat load is at its maximum value; Based on the operation boundary lines of the cogeneration unit before and after the operation optimization, the unit flexibility of the cogeneration unit before and after the operation optimization is compared to determine the unit flexibility analysis result.

9. The method for analyzing the optimized operation of a cogeneration unit based on reheat temperature according to claim 8, characterized in that: The step of calculating the operating boundary line of the cogeneration unit before operation optimization based on the first variable operating condition model when the heating heat load is fixed includes: Setting the heating heat load to a preset reference value; When the industrial heat load is 0, the value of the electric load is calculated by the first variable operating condition model according to the value range of the main steam flow rate, to obtain the pure condensing operating condition operating boundary line of the cogeneration unit before operation optimization; When the main steam flow rate of the cogeneration unit is at its maximum value, calculating the values ​​of the electric load corresponding to the industrial heat load ranging from 0 to its maximum value through the first variable operating condition model, and obtaining the maximum main steam flow rate operating boundary line of the cogeneration unit before operation optimization; When the main steam flow rate of the cogeneration unit is set to its minimum value, the first variable operating condition model is used to calculate the corresponding values ​​of the electric load within the range of the industrial heat load from 0 to its maximum value, thereby obtaining the minimum main steam flow rate operating boundary line of the cogeneration unit before operation optimization; When the industrial heat load is at its maximum value, the value of the electric load is calculated using the first variable operating condition model according to the value range of the main steam flow rate, to obtain the minimum condensate volume line of the low-pressure cylinder of the cogeneration unit before operation optimization; Based on the pure condensing condition operating boundary line, maximum main steam flow operating boundary line, minimum main steam flow operating boundary line and low-pressure cylinder minimum condensing steam volume line of the cogeneration unit before operation optimization, the operating boundary line of the cogeneration unit before operation optimization is obtained.

10. A device for analyzing the optimized operation of a cogeneration unit based on reheat temperature, characterized in that: include: Energy consumption fitting module, used to obtain multiple target operating conditions of the cogeneration unit; Determining an energy consumption fitting formula based on the load data and energy consumption data under the multiple target operating conditions; a first calculation module, configured to obtain a demand load of the cogeneration unit, and calculate a first operating benefit of the cogeneration unit before operation optimization based on the demand load and the energy consumption fitting formula; and determining a reheat temperature under the operating condition corresponding to the demand load before the optimization operation as a first reheat temperature; a second calculation module for determining a second reheat temperature for operation optimization based on the first reheat temperature; calculating a second operating benefit of the cogeneration unit after operation optimization based on the demand load and the second reheat temperature; The second reheat temperature is lower than the first reheat temperature; The benefit analysis module is used to determine an operation benefit analysis result based on the first operation benefit and the second operation benefit.

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