Method and system for quantitatively calculating outlet parameters of reheater based on fuel quantity change

Abstract

The invention discloses a method and system for quantitatively calculating reheater outlet parameters based on fuel quantity changes, and belongs to the technical field of thermal equipment performance state monitoring and diagnosis. According to the method for quantitatively calculating the outlet parameters of the reheater based on the fuel quantity change, a complex thermodynamic process is converted into a computable mathematical model in combination with a differential thought, thermodynamic parameters are obtained based on a thermodynamic chart and the actual operation condition of a unit, unit operation data are collected, and the outlet parameters of the reheater are calculated in combination with a constructed calculation equation. According to the method, the problem that the steam pressure and the steam temperature of the reheater outlet are difficult to quickly, accurately and quantitatively calculate due to the change of the fuel quantity is solved, so that an operator can quickly obtain required information and further take corresponding adjustment measures according to actual conditions, and the accuracy and the reliability of the reheater outlet are improved. And safe, stable and efficient operation of the unit is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal equipment performance status monitoring and diagnosis, and in particular to a method and system for quantitatively calculating reheater outlet parameters based on fuel quantity changes. Background Art

[0002] As the core equipment of supercritical and above thermal power generating units, the operating characteristics of once-through boilers directly impact the overall thermal economy and safety of the units. During actual unit operation, dynamic adjustment of the fuel quantity is a key operation for responding to grid load demands, optimizing combustion efficiency, and coordinating the steam-water cycle. The reheater, a connecting component between the high-pressure and low-pressure cylinders of the steam turbine, is a critical component. Fluctuations in its outlet steam parameters (pressure and temperature) not only restrict the turbine's efficiency but can also potentially lead to safety hazards such as overheating of the heating surfaces and thermal stress imbalances in the steam-water piping. Therefore, establishing a quantitative relationship between changes in fuel quantity and reheater outlet steam parameters is crucial for achieving refined unit control.

[0003] Existing research methods mainly rely on variable operating conditions and experiments to determine the quantitative impact of changes in fuel quantity on the reheater outlet steam pressure and temperature. Variable operating condition experiments require long periods of parameter adjustment and data collection, making it difficult to meet the needs of the operating site for rapid response to sudden changes in operating conditions. They are unable to provide operating personnel with real-time predictions of parameter changes, and are difficult to support accurate diagnosis of boiler performance and dynamic optimization of control strategies. Especially under complex operating conditions such as deep peak regulation of the power grid or fluctuations in fuel quality, this may increase the risk of reheat steam parameter exceeding limits, affecting the safe and economical operation of the unit.

[0004] Therefore, how to achieve rapid and accurate calculation of the changes in reheater outlet steam pressure and steam temperature under fuel quantity disturbance has become a technical problem that needs to be overcome urgently by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and system for quantitatively calculating reheater outlet parameters based on fuel quantity changes, so as to overcome the problem that the variable operating condition test method cannot meet the real-time monitoring and rapid analysis requirements of the unit at the operating site.

[0006] The present invention solves the above technical problems through the following technical solutions: A method for quantitatively calculating reheater outlet parameters based on fuel quantity changes comprises the following steps: Constructing calculation equations, specifically including: constructing a calculation equation for the change in the reheater outlet steam enthalpy based on the boiler's energy balance equation and the differential concept; constructing a calculation equation for the change in the reheater outlet steam pressure based on the turbine high-pressure cylinder thermodynamic process line; and constructing a calculation equation for the change in the reheater outlet steam temperature based on the thermodynamic state equation and the differential concept; Based on the thermodynamic diagrams and the actual operation of the unit, the thermodynamic parameters are obtained and the unit operation data is collected. Combined with the constructed calculation equations, the changes in the reheater outlet steam pressure and the reheater outlet steam temperature are calculated.

[0007] A further improvement of the present invention is that the thermodynamic parameters include: the change in enthalpy of the reheater inlet steam and the constant-pressure specific heat of the reheat outlet steam.

[0008] A further improvement of the present invention is that the unit operating data includes: the change in fuel quantity, the total heat absorbed by boiler steam and water, the heat absorption of reheat outlet steam, the low calorific value of coal, boiler thermal efficiency, the change in reheat outlet steam flow, reheat outlet steam pressure, boiler main steam pressure, the change in boiler main steam pressure, the reheat outlet steam flow and the amount of fuel fed into the boiler.

[0009] A further improvement of the present invention is that the energy balance equation based on the boiler is combined with the differential concept to construct a calculation equation for the change in the steam enthalpy at the reheater outlet, specifically: The energy balance equation of the boiler is:

[0010] is the total heat absorbed by the boiler steam and water, specifically:

[0011] is the enthalpy increase of the reheater steam, specifically:

[0012] in, is the steam enthalpy at the reheater outlet; is the steam enthalpy at the reheater inlet; is the reheat outlet steam flow rate; It is the heat absorption of reheat outlet steam; is the boiler thermal efficiency, The low calorific value of coal; is the amount of fuel fed into the boiler; The heat absorbed by the main steam in the boiler; The flow rate of main steam; is the enthalpy of the main steam outlet; is the enthalpy of boiler feed water; Under the condition that the boiler thermal efficiency and coal quality remain unchanged, the auxiliary coefficient expression is defined as follows:

[0013] Based on the energy balance equation and auxiliary coefficient of the boiler, combined with the differential idea, the calculation equation for the change in the steam enthalpy at the reheater outlet is constructed, specifically:

[0014] in, is the change in steam enthalpy at the reheater outlet; is the change in steam enthalpy at the reheater inlet; is the change in reheat outlet steam flow rate.

[0015] A further improvement of the present invention is that the calculation equation for constructing the reheater outlet steam pressure change specifically includes the following steps: The change in the steam inlet pressure of the high-pressure cylinder of the steam turbine is approximately regarded as the change in the steam pressure at the outlet of the reheater. According to the thermodynamic process line of the high-pressure cylinder of the steam turbine, the calculation equation of the change in the steam pressure at the outlet of the reheater is constructed. Specifically, it is:

[0016] in, is the change in reheat outlet steam pressure; is the reheat outlet steam pressure; is the steam inlet pressure of the high-pressure cylinder of the steam turbine; is the change in steam inlet pressure of the high-pressure cylinder of the steam turbine; is the main steam pressure of the boiler; is the change in the main steam pressure of the boiler.

[0017] A further improvement of the present invention is that: based on the thermodynamic state equation, combined with the differential idea, a calculation equation for the change in the reheater outlet steam temperature is constructed, specifically: According to the thermodynamic state equation and combined with the differential idea, the first equation is constructed, which is:

[0018] in, is the change in reheat outlet steam temperature; is the constant pressure specific heat of the reheat outlet steam, is the effect of unit steam pressure change on steam enthalpy under isothermal conditions; because Much greater than , simplify the first equation and obtain the calculation equation of the reheater outlet steam temperature change, which is: .

[0019] A further improvement of the present invention is that the calculation equation constructed by combining the above is used to calculate the change in the reheater outlet steam pressure and the change in the reheater outlet steam temperature, specifically: The change in reheater outlet steam pressure is calculated based on the unit operating data and the calculation equation for the change in reheater outlet steam pressure; the change in reheater outlet steam temperature is calculated based on the unit operating data, thermodynamic parameters, the calculation equation for the change in reheater outlet steam pressure, and the calculation equation for the change in reheater outlet steam temperature.

[0020] A further improvement of the present invention is that the calculated change in the reheater outlet steam pressure is specifically: Substitute the boiler main steam pressure, boiler main steam pressure change and reheat outlet steam pressure in the unit operation data into the calculation equation of the reheater outlet steam pressure change to calculate the reheater outlet steam pressure change.

[0021] A further improvement of the present invention is that the calculated change in the reheater outlet steam temperature is specifically: Substitute the total heat absorbed by boiler steam and water, the heat absorbed by reheat outlet steam, the low calorific value of coal and boiler thermal efficiency from the unit operation data into the auxiliary coefficient expression to calculate the auxiliary coefficient; Substitute the auxiliary coefficient, the change in the reheater inlet steam enthalpy in the thermodynamic parameters, and the reheater outlet steam flow rate, the change in the reheater outlet steam flow rate, the change in the fuel amount, and the amount of fuel fed into the boiler in the unit operation data into the calculation equation for the change in the reheater outlet steam enthalpy to calculate the change in the reheater outlet steam enthalpy; The change in the enthalpy value of the reheater outlet steam and the constant pressure ratio of the reheater outlet steam in the thermodynamic parameters are introduced into the calculation equation of the change in the reheater outlet steam temperature to calculate the change in the reheater outlet steam temperature.

[0022] The present invention also provides a system for quantitatively calculating reheater outlet parameters based on fuel quantity changes, comprising: The first module is used to construct calculation equations. Specifically, it includes: constructing a calculation equation for the change in the reheater outlet steam enthalpy based on the boiler's energy balance equation and the differential method; constructing a calculation equation for the change in the reheater outlet steam pressure based on the turbine high-pressure cylinder thermodynamic process line; and constructing a calculation equation for the change in the reheater outlet steam temperature based on the thermodynamic state equation and the differential method. The second module is used to obtain thermodynamic parameters and collect unit operation data based on thermodynamic diagrams and the actual operation of the unit, and calculate the change in reheater outlet steam pressure and reheater outlet steam temperature by combining the constructed calculation equations.

[0023] Compared with the prior art, the present invention has the following positive effects: The method provided by the present invention for quantitatively calculating the reheater outlet parameters based on the change in fuel quantity, combines the idea of ​​differentiation, converts a complex thermodynamic process into a computable mathematical model, obtains thermodynamic parameters and collects unit operation data based on thermodynamic diagrams and the actual operation of the unit, and combines the constructed calculation equations to calculate the change in the reheater outlet steam pressure and the change in the reheater outlet steam temperature, thereby solving the problem of rapid and accurate quantitative calculation of the reheater outlet steam pressure and steam temperature due to the change in fuel quantity, enabling operating personnel to quickly obtain the required information and then take corresponding adjustment measures according to the actual situation to ensure the safe, stable and efficient operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0025] Figure 1 Schematic diagram of the flow of the method for quantitatively calculating the reheater outlet parameters based on the change of fuel quantity according to the present invention; Figure 2 Enthalpy-entropy diagram of the enthalpy value of the steam at the reheater inlet of the present invention. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, which are intended to explain the present invention rather than to limit it.

[0029] See also Figure 1 A method for quantitatively calculating reheater outlet parameters based on fuel quantity changes comprises the following steps: Constructing calculation equations, specifically including: constructing a calculation equation for the change in the reheater outlet steam enthalpy based on the boiler's energy balance equation and the differential concept; constructing a calculation equation for the change in the reheater outlet steam pressure based on the turbine high-pressure cylinder thermodynamic process line; and constructing a calculation equation for the change in the reheater outlet steam temperature based on the thermodynamic state equation and the differential concept; Based on the thermodynamic diagrams and the actual operation of the unit, the thermodynamic parameters are obtained and the unit operation data is collected. Combined with the constructed calculation equations, the changes in the reheater outlet steam pressure and the reheater outlet steam temperature are calculated.

[0030] The method provided by the present invention for quantitatively calculating the reheater outlet parameters based on the change in fuel quantity, combines the idea of ​​differentiation, converts a complex thermodynamic process into a computable mathematical model, obtains thermodynamic parameters and collects unit operation data based on thermodynamic diagrams and the actual operation of the unit, and combines the constructed calculation equations to calculate the change in the reheater outlet steam pressure and the change in the reheater outlet steam temperature, thereby solving the problem of rapid and accurate quantitative calculation of the reheater outlet steam pressure and steam temperature due to the change in fuel quantity, enabling operating personnel to quickly obtain the required information and then take corresponding adjustment measures according to the actual situation to ensure the safe, stable and efficient operation of the unit.

[0031] Specifically, the thermodynamic parameters include: the change in enthalpy of the reheater inlet steam and the constant-pressure specific heat of the reheat outlet steam.

[0032] See also Figure 2 The change in the reheater inlet steam enthalpy can be approximated by the enthalpy-entropy diagram (hs diagram) of the reheater inlet steam enthalpy. Specifically, the following steps are included: According to the steam pressure and temperature values ​​at the inlet and outlet of the high-pressure cylinder of the steam turbine, find points A and B on the hs diagram and connect them into line AB. Calculate the change in the main steam pressure and temperature at the boiler outlet. Then find point C on the hs diagram and make the new isobaric line after the fuel quantity disturbance as the reheat outlet steam pressure ( ) + reheat outlet steam pressure ( ), draw parallel lines from point C to A and B, and intersect the new isobaric line at point D, so the change in the enthalpy of the high-pressure cylinder exhaust steam after the fuel quantity disturbance, that is, the change in the enthalpy of the reheater inlet steam, can be obtained. .

[0033] Specifically, the unit operating data includes: change in fuel quantity, total heat absorbed by boiler steam and water, heat absorption of reheat outlet steam, low calorific value of coal, boiler thermal efficiency, change in reheat outlet steam flow, reheat outlet steam pressure, boiler main steam pressure, change in boiler main steam pressure, reheat outlet steam flow and the amount of fuel fed into the boiler.

[0034] Specifically, the energy balance equation of the boiler is combined with the differential concept to construct a calculation equation for the change in the steam enthalpy at the reheater outlet, which is specifically: The energy balance equation of the boiler is:

[0035] is the total heat absorbed by the boiler steam and water, specifically:

[0036] is the enthalpy increase of the reheater steam, specifically:

[0037] in, is the steam enthalpy at the reheater outlet; is the steam enthalpy at the reheater inlet; is the reheat outlet steam flow rate; It is the heat absorption of reheat outlet steam; is the boiler thermal efficiency, The low calorific value of coal; is the amount of fuel fed into the boiler; The heat absorbed by the main steam in the boiler; The flow rate of main steam; is the enthalpy of the main steam outlet; is the enthalpy of boiler feed water; Under the condition that the boiler thermal efficiency and coal quality remain unchanged, the auxiliary coefficient expression is defined as follows:

[0038] Based on the energy balance equation and auxiliary coefficient of the boiler, combined with the differential idea, the calculation equation for the change in the steam enthalpy at the reheater outlet is constructed, specifically:

[0039] in, is the change in steam enthalpy at the reheater outlet; is the change in steam enthalpy at the reheater inlet; is the change in reheat outlet steam flow rate.

[0040] Specifically, the calculation equation for the change in reheater outlet steam pressure includes the following steps: Ignoring the pressure loss in the reheater and the pressure loss in the intermediate pipeline from the reheater to the high-pressure cylinder of the steam turbine, the change in the steam inlet pressure of the high-pressure cylinder of the steam turbine is approximately taken as the change in the steam pressure at the outlet of the reheater. Based on the thermodynamic process line of the high-pressure cylinder of the steam turbine, the calculation equation for the change in the steam pressure at the outlet of the reheater is constructed, which is specifically:

[0041] in, is the change in reheat outlet steam pressure; is the reheat outlet steam pressure; is the steam inlet pressure of the high-pressure cylinder of the steam turbine; is the change in steam inlet pressure of the high-pressure cylinder of the steam turbine; is the main steam pressure of the boiler; is the change in the main steam pressure of the boiler.

[0042] Specifically, based on the thermodynamic state equation and combined with the differential idea, a calculation equation for the change in reheater outlet steam temperature is constructed, which is specifically: According to the thermodynamic state equation and combined with the differential idea, the first equation is constructed, which is:

[0043] in, is the change in reheat outlet steam temperature; is the constant pressure specific heat of the reheat outlet steam, is the effect of unit steam pressure change on steam enthalpy under isothermal conditions; because Much greater than , simplify the first equation and obtain the calculation equation of the reheater outlet steam temperature change, which is: .

[0044] Specifically, the calculation equation constructed in combination is used to calculate the change in the reheater outlet steam pressure and the change in the reheater outlet steam temperature, which are specifically: The change in reheater outlet steam pressure is calculated based on the unit operating data and the calculation equation for the change in reheater outlet steam pressure; the change in reheater outlet steam temperature is calculated based on the unit operating data, thermodynamic parameters, the calculation equation for the change in reheater outlet steam pressure, and the calculation equation for the change in reheater outlet steam temperature.

[0045] Specifically, the calculated change in steam pressure at the reheater outlet is: Substitute the boiler main steam pressure, boiler main steam pressure change and reheat outlet steam pressure in the unit operation data into the calculation equation of the reheater outlet steam pressure change to calculate the reheater outlet steam pressure change.

[0046] Specifically, the calculated change in reheater outlet steam temperature is: Substitute the total heat absorbed by boiler steam and water, the heat absorbed by reheat outlet steam, the low calorific value of coal and boiler thermal efficiency from the unit operation data into the auxiliary coefficient expression to calculate the auxiliary coefficient; Substitute the auxiliary coefficient, the change in the reheater inlet steam enthalpy in the thermodynamic parameters, and the reheater outlet steam flow rate, the change in the reheater outlet steam flow rate, the change in the fuel amount, and the amount of fuel fed into the boiler in the unit operation data into the calculation equation for the change in the reheater outlet steam enthalpy to calculate the change in the reheater outlet steam enthalpy; The change in the enthalpy value of the reheater outlet steam and the constant pressure ratio of the reheater outlet steam in the thermodynamic parameters are introduced into the calculation equation of the change in the reheater outlet steam temperature to calculate the change in the reheater outlet steam temperature.

[0047] Based on the same inventive concept, the present invention also provides a system for quantitatively calculating reheater outlet parameters based on fuel quantity changes, comprising: The first module is used to construct calculation equations. Specifically, it includes: constructing a calculation equation for the change in the reheater outlet steam enthalpy based on the boiler's energy balance equation and the differential method; constructing a calculation equation for the change in the reheater outlet steam pressure based on the turbine high-pressure cylinder thermodynamic process line; and constructing a calculation equation for the change in the reheater outlet steam temperature based on the thermodynamic state equation and the differential method. The second module is used to obtain thermodynamic parameters and collect unit operation data based on thermodynamic diagrams and the actual operation of the unit, and calculate the change in reheater outlet steam pressure and reheater outlet steam temperature by combining the constructed calculation equations.

[0048] Example 1 Taking a 600MW supercritical coal-fired power unit as an example, based on the thermodynamics related charts and the unit operation data, as shown in Table 1, now assume that the fuel quantity changes A case study on the calculation and diagnosis of the changes in the reheat outlet steam temperature and steam pressure is shown in Figure 1.

[0049] Table 1 Summary of thermodynamic parameters and unit operating data

[0050] (1) Substitute the total heat absorbed by the boiler steam and water, the heat absorbed by the reheat outlet steam, the low calorific value of the coal and the thermal efficiency of the boiler in the unit operation data into the auxiliary coefficient expression to calculate the auxiliary coefficient :

[0051] (2) Substitute the auxiliary coefficient, the change in the reheater inlet steam enthalpy in the thermodynamic parameters, the reheater outlet steam flow rate, the change in the reheater outlet steam flow rate, the change in the fuel amount, and the amount of fuel fed to the boiler in the unit operation data into the calculation equation for the change in the reheater outlet steam enthalpy to calculate the change in the reheater outlet steam enthalpy. :

[0052] (3) The change in the enthalpy of the reheater outlet steam and the constant pressure ratio of the reheater outlet steam in the thermodynamic parameters are introduced into the calculation equation of the change in the reheater outlet steam temperature to calculate the change in the reheater outlet steam temperature. :

[0053] This method solves the problem of difficult to accurately quantitatively calculate the effects of fuel quantity changes on the reheater outlet steam pressure and temperature. Through a reasonable simplified formula, it can quickly and relatively accurately obtain the quantitative effects of fuel quantity changes on the reheater outlet steam pressure and temperature, which can assist operating personnel in optimizing operations and ensuring safe and economical operation of the unit; it helps power plant operation engineers to quickly predict and evaluate the quantitative effects of a fuel quantity change on the reheater outlet steam pressure and temperature, so that effective adjustment measures can be taken in a timely manner to ensure safe, stable and efficient operation of the unit.

[0054] Finally, it should be noted that the embodiments listed above are merely one or more specific manifestations of the technical solution of the present invention. Their purpose is to clearly illustrate the concept, principles, and application of the present invention through specific examples, and is in no way intended to limit the scope of protection of the present invention to these specific embodiments. In fact, the true value of this invention lies in its technical ideas and innovations, not in its form of expression or implementation.

[0055] For ordinary technicians in the relevant technical field, after thoroughly reading and understanding the technical solutions of the present invention, they are fully capable of making various forms of changes, modifications or equivalent replacements to the specific implementation methods of the invention based on their own professional knowledge and skills. These changes may include but are not limited to: adjusting the value range of technical parameters, optimizing algorithm processes to improve efficiency, replacing some technical components to achieve better compatibility or reduce costs, etc. As long as these modified technical solutions still substantially maintain the technical features claimed for protection by the original invention, that is, they can still achieve the core functions and effects of the present invention, then these changes should be deemed to fall within the scope of protection of the pending claims of the present invention.

[0056] Furthermore, with the continuous advancement and development of technology, new technical means and methods continue to emerge, providing ample room for further improvement and perfection of the present invention. Therefore, the scope of protection of the present invention should also include reasonably foreseeable improvements and extensions based on existing technologies. As long as these improvements and extensions do not deviate from the basic principles and core concepts of the present invention, they should be considered equivalent to the present invention and equally protected by patent rights.

Claims

1. A method for quantitatively calculating reheater outlet parameters based on fuel quantity changes, characterized in that: The following steps are involved: Constructing a calculation equation, specifically including: based on the boiler's energy balance equation and combined with differential thinking, constructing a calculation equation for the change in the reheater outlet steam enthalpy; Based on the thermal process line of the high-pressure cylinder of the steam turbine, the calculation equation for the change in steam pressure at the reheater outlet is constructed; based on the thermodynamic state equation and combined with the differential idea, the calculation equation for the change in steam temperature at the reheater outlet is constructed; Based on the thermodynamic diagrams and the actual operation of the unit, the thermodynamic parameters are obtained and the unit operation data is collected. Combined with the constructed calculation equations, the changes in the reheater outlet steam pressure and the reheater outlet steam temperature are calculated.

2. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 1, characterized in that: The thermodynamic parameters include: the change in enthalpy of the reheater inlet steam and the constant-pressure specific heat of the reheat outlet steam.

3. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 2, characterized in that: The unit operating data includes: change in fuel quantity, total heat absorbed by boiler steam and water, heat absorption of reheat outlet steam, low calorific value of coal, boiler thermal efficiency, change in reheat outlet steam flow, reheat outlet steam pressure, boiler main steam pressure, change in boiler main steam pressure, reheat outlet steam flow and the amount of fuel fed into the boiler.

4. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 3, characterized in that: Based on the energy balance equation of the boiler and combined with the differential concept, the calculation equation for the change in the enthalpy of the steam at the reheater outlet is constructed, which is specifically: The energy balance equation of the boiler is: is the total heat absorbed by the boiler steam and water, specifically: is the enthalpy increase of the reheater steam, specifically: in, is the steam enthalpy at the reheater outlet; is the steam enthalpy at the reheater inlet; is the reheat outlet steam flow rate; It is the heat absorption of reheat outlet steam; is the boiler thermal efficiency, The low calorific value of coal; is the amount of fuel fed into the boiler; The heat absorbed by the main steam in the boiler; The flow rate of main steam; is the enthalpy of the main steam outlet; is the enthalpy of boiler feed water; Under the condition that the boiler thermal efficiency and coal quality remain unchanged, the auxiliary coefficient expression is defined as follows: Based on the energy balance equation and auxiliary coefficient of the boiler, combined with the differential idea, the calculation equation for the change in the steam enthalpy at the reheater outlet is constructed, specifically: in, is the change in steam enthalpy at the reheater outlet; is the change in steam enthalpy at the reheater inlet; is the change in reheat outlet steam flow rate.

5. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 4, characterized in that: The calculation equation for the change in reheater outlet steam pressure specifically comprises the following steps: The change in the steam inlet pressure of the high-pressure cylinder of the steam turbine is approximately regarded as the change in the steam pressure at the outlet of the reheater. According to the thermodynamic process line of the high-pressure cylinder of the steam turbine, the calculation equation of the change in the steam pressure at the outlet of the reheater is constructed. Specifically, it is: in, is the change in reheat outlet steam pressure; is the reheat outlet steam pressure; is the steam inlet pressure of the high-pressure cylinder of the steam turbine; is the change in steam inlet pressure of the high-pressure cylinder of the steam turbine; is the main steam pressure of the boiler; is the change in the main steam pressure of the boiler.

6. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 5, characterized in that: According to the thermodynamic state equation and combined with the differential idea, the calculation equation for the change in the reheater outlet steam temperature is constructed, which is specifically: According to the thermodynamic state equation and combined with the differential idea, the first equation is constructed, which is: in, is the change in reheat outlet steam temperature; is the constant pressure specific heat of the reheat outlet steam, is the effect of unit steam pressure change on steam enthalpy under isothermal conditions; because Much greater than , simplify the first equation and obtain the calculation equation of the reheater outlet steam temperature change, which is: 。 7. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 6, characterized in that: The calculation equation constructed by combining the above is used to calculate the change in the reheater outlet steam pressure and the change in the reheater outlet steam temperature, specifically: The change in reheater outlet steam pressure is calculated based on the unit operating data and the calculation equation for the change in reheater outlet steam pressure; the change in reheater outlet steam temperature is calculated based on the unit operating data, thermodynamic parameters, the calculation equation for the change in reheater outlet steam pressure, and the calculation equation for the change in reheater outlet steam temperature.

8. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 7, characterized in that: The calculated change in the reheater outlet steam pressure is specifically: Substitute the boiler main steam pressure, boiler main steam pressure change and reheat outlet steam pressure in the unit operation data into the calculation equation of the reheater outlet steam pressure change to calculate the reheater outlet steam pressure change.

9. The method for quantitatively calculating reheater outlet parameters based on fuel quantity changes according to claim 8, characterized in that: The calculated change in reheater outlet steam temperature is specifically: Substitute the total heat absorbed by boiler steam and water, the heat absorbed by reheat outlet steam, the low calorific value of coal and boiler thermal efficiency from the unit operation data into the auxiliary coefficient expression to calculate the auxiliary coefficient; Substitute the auxiliary coefficient, the change in the reheater inlet steam enthalpy in the thermodynamic parameters, and the reheater outlet steam flow rate, the change in the reheater outlet steam flow rate, the change in the fuel amount, and the amount of fuel fed into the boiler in the unit operation data into the calculation equation for the change in the reheater outlet steam enthalpy to calculate the change in the reheater outlet steam enthalpy; The change in the enthalpy value of the reheater outlet steam and the constant pressure ratio of the reheater outlet steam in the thermodynamic parameters are introduced into the calculation equation of the change in the reheater outlet steam temperature to calculate the change in the reheater outlet steam temperature.

10. A system for quantitatively calculating reheater outlet parameters based on fuel quantity changes, characterized in that: include: The first module is used to construct calculation equations. Specifically, it includes: constructing a calculation equation for the change in the reheater outlet steam enthalpy based on the boiler's energy balance equation and the differential method; constructing a calculation equation for the change in the reheater outlet steam pressure based on the turbine high-pressure cylinder thermodynamic process line; and constructing a calculation equation for the change in the reheater outlet steam temperature based on the thermodynamic state equation and the differential method. The second module is used to obtain thermodynamic parameters and collect unit operation data based on thermodynamic diagrams and the actual operation of the unit, and calculate the change in reheater outlet steam pressure and reheater outlet steam temperature by combining the constructed calculation equations.

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