Method and system for calculating acid dew point temperature of boiler flue gas

Abstract

The invention discloses a calculation method and system for the acid dew point temperature of boiler flue gas, and the method comprises the steps: firstly obtaining detailed operation data of a boiler as an analysis basis, and then employing a plurality of different calculation modes to estimate the acid dew point temperature of the flue gas based on the data. The application range of each calculation mode under different working conditions is further determined by comparing and analyzing errors between the calculation results and experimental measurement values. And finally, based on a comparative analysis result, selecting a most accurate calculation mode as a standard calculation scheme of the acid dew point temperature of the boiler flue gas. According to the method, the accuracy of acid dew point temperature prediction is improved, the flexibility and wide applicability of the calculation method are enhanced, and the method has important significance for optimizing boiler operation, prolonging the service life of equipment, saving energy, reducing emission and improving the automation level.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal power plant boilers and relates to a method and system for calculating the acid dew point temperature of boiler flue gas. Background Art

[0003] Under low temperature conditions, when the wall temperature of the low-temperature heating surface is lower than the flue gas acid dew point, sulfuric acid vapor will quickly condense on the low-temperature heating surface, causing low-temperature corrosion of the low-temperature heating surface. Low-temperature corrosion generally occurs at the cold end of the low-temperature air preheater. Low-temperature corrosion can easily cause leakage of the heating surface, which leads to an increase in the amount of air used for combustion and the load of the forced draft fan; it can also easily cause dusting on the low-temperature heating surface, which can force the furnace to shut down in severe cases, and may also replace a large number of heating surfaces, resulting in expensive maintenance costs, thus affecting the economic efficiency of the unit. Therefore, the problem of low-temperature corrosion must be solved. At present, the best way is to increase the exhaust gas temperature to reduce low-temperature corrosion, but too high an exhaust gas temperature will lead to a decrease in the thermal efficiency of the boiler. In actual operation, while ensuring the thermal efficiency of the boiler, it is also necessary to consider the problem of low-temperature corrosion, and try to control the exhaust gas temperature slightly higher than the flue gas acid dew point temperature, so higher requirements are placed on the estimation of the flue gas acid dew point.

[0004] The boiler is one of the three main engines of a thermal power plant. In normal operation, the exhaust loss is the largest heat loss among several heat losses. In addition, there are chemical incomplete combustion heat loss, mechanical incomplete combustion heat loss, heat loss, and ash physical heat loss. Therefore, the accuracy of the calculation of flue gas acid dew point is very important. In addition, modern power plants generally install SCR catalytic devices, so it is even more important to improve the accuracy of flue gas acid dew point calculation and minimize the error between the calculated results and the experimental values.

[0005] The accuracy of flue gas acid dew point calculation is directly related to whether the power plant boiler can operate safely and stably. The direct influencing factor of low-temperature corrosion is sulfuric acid vapor, but at the same time, the waterway point parameter must also be considered in the calculation process. After the sulfuric acid vapor condenses, water vapor will also quickly condense onto the heating surface, and the temperature at which water vapor begins to condense is the water dew point. Current research shows that the sulfuric acid vapor partial pressure and the water vapor partial pressure jointly affect the flue gas acid dew point temperature. However, the calculation formula of the flue gas acid dew point has its limitations. This defect may directly affect the accuracy of the flue gas acid dew point calculation results, which will directly lead to the inability of the power station boiler to operate safely and smoothly, affecting power generation. Summary of the invention

[0006] The purpose of the present invention is to solve the technical problems in the prior art that the calculation of flue gas acid dew point is inaccurate, the error is large, and the influencing factors are not fully considered, and to provide a method and system for calculating the acid dew point temperature of boiler flue gas.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A first aspect of the present invention provides a method for calculating the acid dew point temperature of boiler flue gas, comprising the following steps: Obtain boiler operation data; Based on boiler operation data, choose different calculation methods to calculate the flue gas acid dew point temperature; Compare and analyze the errors between the calculated results and the experimental values ​​to determine the applicable scope of different calculation methods; Based on the applicable scope of different calculation methods, the accuracy of different calculation methods is determined, and the most accurate calculation method is used as the calculation scheme for the acid dew point of boiler flue gas.

[0008] Furthermore, the boiler operation data includes sulfuric acid vapor volume fraction, water vapor volume fraction, sulfuric acid vapor concentration, water vapor concentration, excess air coefficient and coal type.

[0009] Further, the method of calculating the flue gas acid dew point temperature by selecting different calculation methods based on the boiler operation data includes: Muller curve, Soviet formula, Halstead curve fitting formula, AGOkkes formula, Japan Electric Research Institute empirical formula, Haase & Borgman formula and и.A.Bapahob formula.

[0010] Furthermore, the error between the calculation result and the experimental value is compared and analyzed to determine the applicable scope of different calculation methods, specifically: Obtain experimental measurements that match the calculated conditions as a comparison benchmark; Calculate the error between each calculated result and the experimental value; According to the comparative analysis results, each calculation method is ranked according to the degree of agreement between the calculation results and the experimental values, and the applicable scope of each formula is determined.

[0011] Furthermore, the accuracy of different calculation methods is determined based on the applicable scope of different calculation methods, and the most accurate calculation method is used as the calculation method for the acid dew point of boiler flue gas, including: Based on the calculation results, a solution to prevent and control low-temperature corrosion is proposed, and the accuracy of the flue gas acid dew point calculation formula is verified; Different calculation methods are used to calculate the flue gas acid dew point temperature of different coal types under different working conditions, and the calculation results are compared and analyzed to obtain the accuracy of different flue gas acid dew point calculation formulas; The flue gas acid dew point temperature is calculated by using the control variable method to determine the accuracy of the flue gas acid dew point calculation method; The calculation method with the highest accuracy is used as the calculation method for the acid dew point temperature of boiler flue gas.

[0012] Furthermore, based on the calculation results, a solution for preventing and controlling low-temperature corrosion is proposed, and the accuracy of the calculation method of flue gas acid dew point is verified, specifically: Based on the applicable scope of the calculation method of flue gas acid dew point, a targeted low-temperature corrosion prevention and control plan is proposed; Implement low-temperature corrosion prevention and control programs on power plant boilers, set up monitoring points, and record monitoring data; The accuracy of the flue gas acid dew point calculation method is verified through monitoring data.

[0013] Furthermore, different calculation methods are used to calculate the flue gas acid dew point temperature of different types of coal under different working conditions, and the calculation results are compared and analyzed to obtain the accuracy of different flue gas acid dew point calculation formulas, specifically: Different flue gas acid dew point calculation methods are used to calculate the flue gas acid dew point temperature of different coal types under different working conditions; The flue gas acid dew point temperatures calculated by different flue gas acid dew point calculation methods were compared and analyzed to evaluate the accuracy of the flue gas acid dew point calculation method.

[0014] Furthermore, the types of coal include bituminous coal, lean coal, anthracite and lignite.

[0015] Furthermore, the control variable method is used to calculate the flue gas acid dew point temperature and determine the accuracy of the flue gas acid dew point temperature calculation method, specifically: Select the main variables that affect the flue gas acid dew point temperature; The control variable method is used to change each variable one by one while keeping other variables unchanged to calculate the flue gas acid dew point temperature; Draw a flue gas acid dew point temperature variation curve diagram according to the calculated flue gas acid dew point temperature; The flue gas acid dew point temperature variation curve is compared with the actual operation of the power plant boiler to evaluate the accuracy of the flue gas acid dew point temperature calculation method.

[0016] A second aspect of the present invention provides a boiler flue gas acid dew point temperature calculation system, comprising: Data acquisition module, to acquire boiler operation data; The calculation module selects different calculation methods to calculate the flue gas acid dew point temperature based on the boiler operation data; The application scope analysis module compares and analyzes the errors between the calculation results and the experimental values ​​to determine the application scope of different calculation methods; The accuracy verification module determines the accuracy of different calculation methods based on their applicable scopes, and uses the most accurate calculation method as the calculation scheme for the acid dew point of boiler flue gas.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a method for calculating the acid dew point temperature of boiler flue gas. By acquiring detailed boiler operation data and using a variety of calculation methods based on these data to estimate the acid dew point temperature of flue gas, the most accurate calculation method can be accurately screened out by comparing and analyzing the errors between the calculation results and the experimental values. This process effectively reduces the calculation error, improves the accuracy of acid dew point temperature prediction, and provides a reliable basis for the safe operation and efficient maintenance of the boiler. The present invention is not limited to a single calculation model, but flexibly selects and verifies a variety of calculation methods according to the specific operating conditions and flue gas characteristics of the boiler. This flexibility ensures that the most suitable calculation scheme can be found under different working conditions, significantly enhancing the applicability and extensiveness of the calculation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 This is a block diagram of a method for calculating the acid dew point temperature of boiler flue gas according to the present invention; Figure 2 The curve of acid dew point calculated by I.A.Bapahoba formula versus sulfuric acid vapor volume fraction; Figure 3 This is the Mueller curve fitting type flue gas acid dew point curve changing with sulfuric acid vapor volume fraction; Figure 4 The Halstead curve fitting formula is the flue gas acid dew point curve changing with the volume fraction of sulfuric acid vapor; Figure 5 This is the curve of flue gas acid dew point changing with sulfuric acid vapor volume fraction according to the empirical formula of Japan Electric Research Institute; Figure 6 This is the curve of the empirical formula of the Japan Electric Research Institute as the water vapor volume fraction changes; Figure 7 This is the flue gas acid dew point variation curve with water vapor volume fraction according to A. Bapahoba formula; Figure 8 This is a block diagram of a boiler flue gas acid dew point temperature calculation system according to the present invention; DETAILED DESCRIPTION In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and marked in the drawings here can be arranged and designed in various different configurations.

[0020] 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 claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0022] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0023] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0024] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings: See also Figure 1The present invention provides a method for calculating the acid dew point temperature of boiler flue gas, comprising the following steps: S1, obtain boiler operation data; obtain the operation data of coal-fired boilers under different working conditions. The data includes but is not limited to flue gas composition (SO3, water vapor, O2, etc.), flue gas temperature, excess air coefficient, coal characteristics (sulfur content, ash content, moisture, etc.).

[0026] S2, based on the boiler operation data, select different calculation methods to calculate the flue gas acid dew point temperature; the present invention uses the following calculation methods: Mueller Curve: t sld =116.5515+16.06329 lgV SO3 +1.05377( VxV SO3 ) 2 Soviet formula: t sld = t ld +

[0027] Halstead curve fitting formula: t sld =113.0219+15.0777 lgV H2SO4 +2.0975( lgV H2SO4 ) 2 AGOkkes formula: t sld =203.25+10.83 lgp SO3 +27.61 lgp H20 +1.06( lgp SO3 +8) 2.19 Japan Electric Research Institute's empirical formula: t sld =20 lgV SO3 + a -80 Haase&Borgman formula: t sld =255+27.6 lgpSO3 +18.7 lgp H2O и.A.Bapahob formula: t sld =186+26 lgφ SO3 +20 lgφ H2O in, V SO3 is the volume parts per million of SO3 in the flue gas; t ld is the dew point of pure water vapor, °C; Sar, red is the sulfur content of fuel, % A ar,red is the fuel ash content, %; S ar is the as-received sulfur content of the fuel, %; A ar is the received basis ash content of the fuel, %; Q net，ar,p The basic low calorific value of the fuel is kJ / kg; α h is the fly ash share; β It is a coefficient related to the excess air coefficient at the furnace outlet, and the standard is generally 125; V H2SO4 is the volume parts per million of H2SO4; t ld is the dew point of pure water vapor, °C; P H2SO4 is the partial pressure of H2SO4 vapor in the flue gas, atm; P SO3 is the partial pressure of SO3 in flue gas, atm; a is a constant related to the moisture content of flue gas. When the moisture content is 5%, 10%, and 15%, a Take 184, 194, 201 respectively; B and n are experimental constants; Φ SO3 is the volume fraction of SO3 in flue gas, %; Φ H20 is the volume fraction of water vapor in the flue gas, %; n is the conversion coefficient of SO3, which is generally taken as 3. It can be taken as 4-5 after the unit is equipped with SCR denitrification device.

[0028] S3, compare and analyze the errors between the calculated results and the experimental values ​​to determine the applicable scope of different calculation methods; it is necessary to compare the flue gas acid dew point calculation results obtained by various calculation methods (such as the empirical formula of the Japan Electric Research Institute, the И.A.BapahoBa formula, the Halstead curve fitting formula, the Mueller curve, etc.) with the actual values ​​obtained by experimental measurement. By calculating the error (such as absolute error, relative error, etc.), the accuracy of each calculation method under different conditions can be evaluated. Furthermore, based on the results of the error analysis, the specific scope of application of each calculation method can be determined, such as specific fuel types, flue gas component ratios, operating conditions, etc.

[0029] S4, based on the applicable scope of different calculation methods, determine the accuracy of different calculation methods, and use the most accurate calculation method as the calculation scheme for boiler flue gas acid dew point.

[0030] After completing step S3, you have a preliminary understanding of the accuracy and applicable scope of various calculation methods. Next, you need to consider various factors (such as calculation accuracy, calculation complexity, applicable scope, etc.) and select the calculation method that best suits the current boiler operating conditions and needs: S401. Based on the calculation results, propose a plan to prevent and control low-temperature corrosion, and verify the accuracy of the flue gas acid dew point calculation formula and their respective applicable conditions; based on the analysis results of step S3, propose a prevention and control plan for boiler low-temperature corrosion; including adjusting boiler operating parameters (such as combustion temperature, excess air coefficient, etc.), optimizing coal ratio, using corrosion-resistant materials, etc. At the same time, select a variety of calculation methods as references, verify the accuracy of these calculation formulas through measurement data in actual applications, and further clarify their applicable conditions.

[0031] S402. Use multiple acid dew point formulas to calculate the flue gas acid dew point temperature of bituminous coal, anthracite, lean coal and lignite under different working conditions, compare and analyze the calculation results, and obtain the applicable scope and accuracy of different flue gas acid dew point calculation formulas; select multiple representative flue gas acid dew point calculation formulas, and calculate the flue gas acid dew point temperature under different working conditions (such as different coal types, different combustion conditions, etc.). By comparing and analyzing the calculation results, we can understand the performance differences of different formulas under different conditions, so as to further determine their applicable scope and accuracy.

[0032] S403. Use the control variable method to change another influencing factor and keep one variable unchanged to calculate the flue gas acid dew point, and draw a curve chart of the flue gas acid dew point changing with the change of the variable, analyze and compare with the actual operation of the power plant boiler, and judge the accuracy of the flue gas acid dew point calculation formula. According to the known sulfuric acid vapor volume fraction, water vapor volume fraction, coal type, excess air coefficient and other conditions, the commonly used flue gas acid dew point temperature calculation formula is used to calculate the flue gas acid dew point. Using the control variable method, one factor remains unchanged while the other factor changes to calculate the flue gas acid dew point, and draw its trend curve with the change of the variable. And compare the curves to compare the differences between them. After the calculation and drawing are completed, analyze the degree of change of the flue gas acid dew point with the change of each influencing factor. In the process of low-temperature corrosion, the corrosion rate is not constant. The corrosion rate does not necessarily increase with the increase of condensate content. This depends on the relationship between the wall temperature of the heating surface and the flue gas acid dew point temperature.

[0033] Based on the analysis results and verification data of the above steps, the most accurate and reliable flue gas acid dew point calculation method is selected as the calculation scheme for boiler flue gas acid dew point. This scheme will serve as an important basis for subsequent boiler design, operation optimization and corrosion prevention.

[0034] An implementation of the present invention uses calculation formulas such as the I.A. Bapahoba formula, the Halstead curve fitting formula, the Mueller curve fitting formula, and the Japanese Electric Research Institute empirical formula: According to the boiler operation data, the input parameters required for each calculation method are set to obtain the flue gas acid dew point temperature under each calculation method: The known conditions for flue gas acid dew point are as follows: The volume fraction of sulfuric acid vapor is 6-15ppm; the volume fraction of water vapor is 3-15%; excess air coefficient; coal type (bituminous coal, lean coal, anthracite, lignite).

[0035] Table 1. Flue gas acid dew point calculated by A. Bapahoba formula

[0036] Table 2 Calculation results of flue gas acid dew point based on Halstead curve fitting formula

[0037] Table 3 Calculation results of flue gas acid dew point based on Mueller curve fitting formula

[0038] Table 4 Calculation results of flue gas acid dew point based on the empirical formula of the Japan Electric Research Institute

[0039] like Figure 1-4 As shown in the figure, these four formulas predict the change trend of flue gas acid dew point under the condition of changing sulfuric acid vapor volume fraction (assuming that the water vapor volume fraction is constant at 3%).

[0040] When comparing the Halstead curve fitting formula, Mueller curve, I.A. Bapahoba formula and the empirical formula of the Japan Institute of Electrical Engineering, specifically, the calculation results of the Halstead curve fitting formula and the Mueller curve are relatively close, and both are close to 130 in the minimum value, showing a similar trend; the minimum value calculated by the I.A. Bapahoba formula is relatively low, while the minimum value of the empirical formula of the Japan Institute of Electrical Engineering is slightly less than 120, both lower than the former two. In terms of the maximum value, the I.A. Bapahoba formula and the empirical formula of the Japan Institute of Electrical Engineering remain below 130, while the maximum values ​​of the Halstead and Mueller curve fitting formulas fall in the range of 130 to 140, and are close to each other.

[0041] This difference is mainly attributed to the different factors considered in the design of each calculation method. Both the Mueller curve fitting formula and the Halstead curve fitting formula only consider the volume percentage of sulfuric acid vapor as a variable, ignoring the change in the volume fraction of water vapor. This limitation makes these two formulas not comprehensive enough when simulating complex flue gas environments, and then when compared with other more comprehensive formulas (such as the и.A.Bapahoba formula and the empirical formula of the Japan Electric Research Institute), some factors are missing or insufficient.

[0042] The volume fraction of sulfuric acid vapor is controlled to be constant, and the formula of A. Bapahoba and the empirical formula of the Japanese Institute of Electrical Engineering are further compared: Table 5 Flue gas acid dew point calculated according to the formula of I.A.Bapahoba

[0043] Table 6 Calculation results of flue gas acid dew point based on the empirical formula of the Japan Electric Research Institute

[0044] Figure 5-6 The following are the curves of flue gas acid dew point calculated by the empirical formula of the Japan Electric Research Institute and the И.A.BapahoBa estimation formula as the volume fraction of sulfuric acid vapor changes; it can be seen that the trend of the graph of the empirical formula of the Japan Electric Research Institute is that the acid dew point first remains unchanged and then increases as the volume fraction of sulfuric acid vapor increases. The trend of the И.A.BapahoBa estimation formula is that the acid dew point increases as the volume fraction of sulfuric acid vapor increases, but it tends to be relatively flat in the later period.

[0045] By comparing the empirical formula of the Japanese Institute of Electrical and Electronics Research and the estimated formula of I.A. BapahoBa, it is found that the value of a in the empirical formula of the Japanese Institute of Electrical and Electronics Research is the same when the water vapor volume fraction is from 3% to 5%, while in the estimated formula of I.A. BapahoBa, the water vapor volume fraction is changing, so the changing trends of the curves finally drawn by the two are different.

[0046] For different types of coal: When the coal types are different but the sulfur content is the same, the difference in the received lower calorific value of the coal will directly affect the calculation of the converted sulfur content. Specifically, a higher received lower calorific value may correspond to a lower converted sulfur content, and vice versa. Since the calculation of the flue gas acid dew point depends on the converted sulfur content, this difference will result in different flue gas acid dew points calculated for different types of coal at the same sulfur content. The Soviet empirical formula took into account the effects of ash and water dew point on the flue gas acid dew point when it was designed. This comprehensive consideration makes the flue gas acid dew point calculated by the Soviet empirical formula relatively low in some cases. Compared with other formulas that do not take these factors into account, its accuracy is reduced and it is closer to the complex situations in actual operation, thus reflecting its unique accuracy and applicability to a certain extent.

[0047] Table 7 shows the sulfur content of coal types: Table 7 Sulfur content of coal types and their received base lower calorific value

[0048] The present invention finds an accurate flue gas acid dew point calculation method by analyzing the applicable conditions and limitations of the flue gas acid dew point calculation formula: different flue gas acid dew point calculation formulas can be substituted according to known conditions (acid, water vapor concentration, coal type, excess air coefficient, etc.) for calculation, and the calculation results are compared and analyzed to find the applicable conditions and limitations of different formulas, thereby proposing a correction method for the flue gas acid dew point calculation formula, determining the minimum flue gas exhaust temperature of the boiler unit under this operating condition according to the acid dew point temperature, and further proposing measures to prevent low-temperature corrosion.

[0049] See also Figure 8 The present invention provides a boiler flue gas acid dew point temperature calculation system, comprising: Data acquisition module, to acquire boiler operation data; The calculation module selects different calculation methods to calculate the flue gas acid dew point temperature based on the boiler operation data; The application scope analysis module compares and analyzes the errors between the calculation results and the experimental values ​​to determine the application scope of different calculation methods; The accuracy verification module determines the accuracy of different calculation methods based on their applicable scopes, and uses the most accurate calculation method as the calculation scheme for the acid dew point of boiler flue gas.

[0050] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for calculating the acid dew point temperature of boiler flue gas, characterized in that: The following steps are involved: Obtain boiler operation data; Based on boiler operation data, choose different calculation methods to calculate the flue gas acid dew point temperature; Compare and analyze the errors between the calculated results and the experimental values ​​to determine the applicable scope of different calculation methods; Based on the applicable scope of different calculation methods, the accuracy of different calculation methods is determined, and the most accurate calculation method is used as the calculation scheme for the acid dew point of boiler flue gas.

2. The method for calculating the acid dew point temperature of boiler flue gas according to claim 1, characterized in that: The boiler operation data include sulfuric acid vapor volume fraction, water vapor volume fraction, sulfuric acid vapor concentration, water vapor concentration, excess air coefficient and coal type.

3. The method for calculating the acid dew point temperature of boiler flue gas according to claim 1, characterized in that: The method of calculating the flue gas acid dew point temperature based on the boiler operation data includes: Muller curve, Soviet formula, Halstead curve fitting formula, AGOkkes formula, Japan Electric Research Institute empirical formula, Haase & Borgman formula and и.A.Bapahob formula.

4. The method for calculating the acid dew point temperature of boiler flue gas according to claim 1, characterized in that: The error between the comparative analysis calculation results and the experimental values ​​is used to determine the applicable scope of different calculation methods, specifically: Obtain experimental measurements that match the calculated conditions as a comparison benchmark; Calculate the error between each calculated result and the experimental value; According to the comparative analysis results, each calculation method is ranked according to the degree of agreement between the calculation results and the experimental values, and the applicable scope of each formula is determined.

5. The method for calculating the acid dew point temperature of boiler flue gas according to claim 1, characterized in that: The accuracy of different calculation methods is determined based on the applicable scope of different calculation methods, and the most accurate calculation method is used as the calculation method for the acid dew point of boiler flue gas, including: Based on the calculation results, a solution to prevent and control low-temperature corrosion is proposed, and the accuracy of the flue gas acid dew point calculation formula is verified; Different calculation methods are used to calculate the flue gas acid dew point temperature of different coal types under different working conditions, and the calculation results are compared and analyzed to obtain the accuracy of different flue gas acid dew point calculation formulas; The flue gas acid dew point temperature is calculated by using the control variable method to determine the accuracy of the flue gas acid dew point calculation method; The calculation method with the highest accuracy is used as the calculation method for the acid dew point temperature of boiler flue gas.

6. The method for calculating the acid dew point temperature of boiler flue gas according to claim 5, characterized in that: Based on the calculation results, a solution for preventing and controlling low-temperature corrosion is proposed, and the accuracy of the calculation method of flue gas acid dew point is verified, specifically: Based on the applicable scope of the calculation method of flue gas acid dew point, a targeted low-temperature corrosion prevention and control plan is proposed; Implement low-temperature corrosion prevention and control programs on power plant boilers, set up monitoring points, and record monitoring data; The accuracy of the flue gas acid dew point calculation method is verified through monitoring data.

7. The method for calculating the acid dew point temperature of boiler flue gas according to claim 5, characterized in that: The flue gas acid dew point temperature of different coal types under different working conditions is calculated by using different calculation methods, and the calculation results are compared and analyzed to obtain the accuracy of different flue gas acid dew point calculation formulas, specifically: Different flue gas acid dew point calculation methods are used to calculate the flue gas acid dew point temperature of different coal types under different working conditions; The flue gas acid dew point temperatures calculated by different flue gas acid dew point calculation methods were compared and analyzed to evaluate the accuracy of the flue gas acid dew point calculation method.

8. The method for calculating the acid dew point temperature of boiler flue gas according to claim 7, characterized in that: The types of coal include bituminous coal, lean coal, anthracite and lignite.

9. The method for calculating the acid dew point temperature of boiler flue gas according to claim 5, characterized in that: The control variable method is used to calculate the flue gas acid dew point temperature and determine the accuracy of the flue gas acid dew point temperature calculation method, specifically: Select the main variables that affect the flue gas acid dew point temperature; The control variable method is used to change each variable one by one while keeping other variables unchanged to calculate the flue gas acid dew point temperature; Draw a flue gas acid dew point temperature variation curve diagram according to the calculated flue gas acid dew point temperature; The flue gas acid dew point temperature variation curve is compared with the actual operation of the power plant boiler to evaluate the accuracy of the flue gas acid dew point temperature calculation method.

10. A boiler flue gas acid dew point temperature calculation system, based on the boiler flue gas acid dew point temperature calculation method according to claim 1, characterized in that: include: Data acquisition module, to acquire boiler operation data; The calculation module selects different calculation methods to calculate the flue gas acid dew point temperature based on the boiler operation data; The application scope analysis module compares and analyzes the errors between the calculation results and the experimental values ​​to determine the application scope of different calculation methods; The accuracy verification module determines the accuracy of different calculation methods based on their applicable scopes, and uses the most accurate calculation method as the calculation scheme for the acid dew point of boiler flue gas.

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