Practical energy efficiency evaluation method for boiler of self-provided power plant of iron and steel complex

Abstract

The utility model relates to a kind of practical energy efficiency evaluation method of steel joint enterprise self-provided power plant boiler, solve the problem that remaining coal gas fluctuates frequently, resulting in the unstable gas supply and gas calorific value of boiler, the energy efficiency of steel plant boiler system cannot effectively carry out analysis work, and boiler energy saving and carbon reduction work lacks reference basis.The practical energy efficiency evaluation method of the boiler establishes the boiler energy efficiency evaluation mode under the condition of fuel quantity and fuel calorific value fluctuation, and establishes the steel plant boiler thermal efficiency accounting interval method model formed by coal gas calorific value interval method, coal gas calorific value and boiler efficiency correlation model, boiler thermal efficiency optimization interval analysis method, and carries out analysis diagnosis.The evaluation method can solve the practical energy efficiency evaluation problem of boiler under the condition of steel plant boiler fuel fluctuation and unknown coal gas calorific value according to the actual condition of steel enterprise boiler system, effectively guide the analysis diagnosis and optimization improvement work of steel plant boiler system.

Description

Technical Field

[0001] This invention belongs to the field of industrial artificial intelligence technology in metallurgical automation. Specifically, it relates to a practical energy efficiency evaluation method for boilers in integrated steel enterprises that can solve the problem of boiler practical energy efficiency evaluation under conditions of fluctuating boiler fuel and unknown gas calorific value, and effectively guide the analysis, diagnosis and optimization of boiler systems in steel plants. Background Technology

[0002] Coal gas is a valuable secondary energy source for steel plants. Blast furnace gas (BFG), coke oven gas (COG), and converter gas (LDG) are generated during the smelting processes of blast furnaces, coke ovens, and converters, respectively. After recovery, the gas enters the gas pipeline network. After being used by various users, the remaining gas is consumed by the boilers in the self-owned power plant. The surplus gas in steel plants accounts for approximately 40% of the total gas volume, and is used to generate steam for power generation in the self-owned power plant. Due to the diverse types of gas users, their varying production rhythms, and different gas pressure requirements, the gas flow rate fluctuates significantly, resulting in frequent fluctuations in the surplus gas reaching the self-owned power plant boilers and unstable calorific value. Because boilers are end-users of gas resources in steel plants, their relative importance is weaker than the main production processes such as ironmaking, steelmaking, and rolling. Therefore, steel companies do not install gas calorific value measuring instruments at the boiler end. Furthermore, the frequent fluctuations in gas volume render conventional boiler energy efficiency evaluation methods ineffective, hindering effective energy efficiency analysis of the steel plant boiler system and lacking effective reference data for boiler energy conservation and carbon reduction efforts. Therefore, it is necessary to improve the existing energy efficiency evaluation methods for self-owned power plant boilers. Summary of the Invention

[0003] This invention addresses the aforementioned problems by providing a practical energy efficiency evaluation method for boilers in integrated steel enterprises' self-owned power plants that can solve the problem of boiler practical energy efficiency evaluation under conditions of fluctuating boiler fuel and unknown gas calorific value. This method effectively guides the analysis, diagnosis, optimization, and improvement of boiler systems in steel plants.

[0004] The technical solution adopted in this invention is as follows: The practical energy efficiency evaluation method for boilers in self-owned power plants of integrated iron and steel enterprises includes the following steps:

[0005] Step 1: Analysis of the calorific value variation of the supplied boiler gas; the calorific value of the gas is affected by the supply of BFG, COG, and LDG and their corresponding lower heating values; and while the gas flow rate can be obtained through a metering system, the calorific value is unknown. Therefore, the interval method is more reasonable than the fixed value method for calorific value analysis; the interval method for gas calorific value is expressed as [H min H max The calorific value of the gas supplied to the boiler end of the steel plant cannot be obtained accurately, and is expressed as a certain range.

[0006] Step 2: Establish a correlation model between the calorific value of coal gas and boiler efficiency; use thermal efficiency to measure the boiler's operating performance, and then evaluate the boiler's energy efficiency.

[0007] Step 3: Calculate the range of optimal boiler thermal efficiency using interval analysis; use historical data analysis to statistically analyze the gas supply V and the corresponding boiler efficiency for the most recent N days.

[0008] Step 4: Determine the boiler operating range;

[0009] Step 5: Boiler energy efficiency evaluation.

[0010] In step one, the calculation of the calorific value of the gas is shown in equation (1):

[0011]

[0012] In the formula: V BFG V COG V LDG These represent the flow rates of BFG, COG, and LDG supplied to the boiler, respectively.

[0013] H BFG H COG H LDG These represent the lower heating values ​​of BFG, COG, and LDG, respectively.

[0014] Furthermore, the calorific value of BFG ranges from approximately 3000 to 4400 kJ / Nm³. 3 The calorific value of COG ranges from approximately 15,000 to 17,800 kJ / Nm³. 3 The calorific value of LDG ranges from approximately 6000 to 7500 kJ / Nm³. 3 From equation (1), it can be seen that the calorific value H of the mixed gas is... 热值 The range is 3000–17800 kJ / Nm 3 Since the volume of various types of gas is changing, the mixing ratio of the gas supplied to the boiler is constantly changing, and the calorific value of the gas will also vary within a certain range at different times.

[0015] As can be seen from the boiler operating process principle in step two, the boiler thermal efficiency is the ratio of the effective heat of the boiler to the total heat brought in by the raw materials, as shown in equation (2):

[0016]

[0017] In the formula: η represents the thermal efficiency of the boiler;

[0018] Q 有效 Indicates the effective heat capacity of the boiler;

[0019] Q 送入 This indicates the total heat carried into the boiler by the fuel fed into the furnace;

[0020] h 蒸汽 h 给水 These represent the enthalpy values ​​of boiler steam and feedwater, respectively.

[0021] Furthermore, the total heat Q brought into the boiler by the fuel is... 送入 The calculation formula is as follows:

[0022] Q 送入 =V 煤气 ×H 热值 (3)

[0023] In the formula: V 煤气 This indicates the volume of gas supplied to the boiler.

[0024] H 热值 This indicates the calorific value of the gas fed into the boiler.

[0025] Furthermore, as can be seen from equations (2) and (3), the calorific value of the gas is inversely proportional to the boiler efficiency. In the boiler efficiency calculation process, based on the actual situation of the steel enterprise, the steam and feedwater enthalpy values ​​of the self-owned power plant boiler can be directly measured. The lowest and highest values ​​of the gas calorific value range are respectively taken to participate in the calculation of equation (2) to obtain the corresponding thermal efficiency range of the boiler.

[0026] Step three involves calculating the boiler efficiency within the statistical period; for a 30-day statistical period, the probability of boiler efficiency occurring is above 90%; based on the statistical data, the following calculation process is established to address this:

[0027] ① Divide the 30 statistical periods into V i It indicates that, with V i The corresponding boiler efficiency is η i , i = {1, 2, ..., 30};

[0028] ② Each V i The corresponding boiler thermal efficiency line segments are used to determine the maximum efficiency values. and minimum value Forming a 30-day gas supply V i The set of maximum and minimum efficiency values ​​at any given time

[0029] ③ Order and Representing sets The maximum and minimum values;

[0030] ④ Order and Representing sets The maximum and minimum values;

[0031] ⑤ Order where a% represents the proportion;

[0032] Let where b% represents the proportion;

[0033] ⑥ Let a% = b% = 90%, then the new efficiency range [MIN, MAX] is the gas supply volume V of the boiler system i when it is the most reasonable efficiency range, and the incidence rate accounts for more than 90%.

[0034] In the fourth step, let γ represent the ratio of the actual fuel supply volume of the boiler to the rated fuel volume, and its calculation process is as follows:

[0035]

[0036] η b (γ) = -74.36γ 2 +162.58γ + 3.15 (5)

[0037] In the formula: v b represents the fuel volume supplied to boiler b;

[0038] represents the standard value of the fuel volume supplied to boiler b.

[0039] In the fifth step, for any boiler of the steel enterprise, call formula (2) to calculate the boiler efficiency η 锅炉 , if η 锅炉 ∈[MAX, MIN], it means the boiler is operating reasonably; if η 锅炉 > the MAX line, it means the thermal efficiency of the boiler at this moment is relatively high, but it cannot maintain long-term stability, will soon fluctuate and drop, not only the boiler operation is not efficient, but it will also cause the boiler working conditions to fluctuate, which is not conducive to the boiler operation; and if η 锅炉 < the MIN line, it means the boiler is operating inefficiently, and a prompt message needs to be sent to the system to remind the enterprise's gas dispatching to make improvements to ensure the efficient operation of the steel plant boiler.

[0040] Advantages of the present invention: The practical energy efficiency evaluation method for the boilers of the self-provided power plant of the iron and steel joint enterprise establishes an energy efficiency evaluation method for boilers under the conditions of fuel volume and fuel calorific value fluctuations; and establishes a heat efficiency calculation interval method model for the boilers of the steel plant composed of the gas calorific value interval method, the correlation model between gas calorific value and boiler efficiency, and the analysis and diagnosis of the optimized interval of boiler thermal efficiency. This practical energy efficiency evaluation method for boilers can solve the problem of practical energy efficiency evaluation of boilers under the conditions of fuel fluctuations and unknown gas calorific value in the steel plant boiler system according to the actual conditions of the steel enterprise boiler system, and effectively guide the analysis, diagnosis, optimization and improvement work of the steel plant boiler system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a simplified diagram of the gas production and consumption system in a steel plant.

[0042] Figure 2 This is a flowchart analyzing the energy efficiency evaluation problem of steel plant boilers according to the present invention.

[0043] Figure 3 The boiler gas load V of the present invention i And the corresponding boiler thermal efficiency range diagram.

[0044] Figure 4 This is a statistical and sequence diagram of the boiler efficiency range corresponding to the boiler gas supply V of the present invention.

[0045] Figure 5 This invention uses the interval analysis method to calculate the boiler thermal efficiency distribution diagram.

[0046] Figure 6 This is a fitting curve of boiler efficiency variation according to the present invention.

[0047] Figure 7 This is a theoretical schematic diagram of the high-efficiency green zone for boiler operation according to the present invention.

[0048] Figure 8 This is a schematic diagram of the actual operation of the boiler in the high-efficiency green zone in this embodiment of the invention. Detailed Implementation

[0049] To address the challenges of fluctuating residual gas volume and varying calorific value in steel plants, coupled with the lack of calorific value measurement instruments, this invention proposes a boiler efficiency range method to solve the practical evaluation problem of boiler energy efficiency and guide the optimized operation of steel plant boiler systems. The boiler efficiency range method comprises a gas calorific value range method, a correlation model between gas calorific value and boiler efficiency, and a boiler thermal efficiency optimization range analysis method.

[0050] The specific steps of this invention are described in detail. The practical energy efficiency evaluation method for boilers in self-owned power plants of integrated steel enterprises includes:

[0051] Step 1: Analysis of changes in the calorific value of the gas supplied to the boiler.

[0052] The fuels used in steel plant boilers are blast furnace gas (BFG), coke oven gas (COG), converter gas (LDG), and their mixed gas (MG). The volume of the remaining gas fluctuates frequently, the composition of each gas type fluctuates, the calorific value of the gas is unstable, and there is no calorific value meter to measure the gas entering the boiler.

[0053] Due to frequent fluctuations in surplus gas from steel plants, and the lack of gas calorific value measurement when it reaches the boiler via pipeline, boiler efficiency cannot be directly calculated, and there is no reasonable solution, which is a current industry problem. The calorific value of gas is affected by the supply of BFG, COG, and LDG and their corresponding lower heating values, as shown in equation (1):

[0054]

[0055] In the formula: V BFG V COG V LDG These represent the flow rates of BFG, COG, and LDG supplied to the boiler, respectively.

[0056] H BFG H COG H LDG These represent the lower heating values ​​of BFG, COG, and LDG, respectively.

[0057] BFG has a calorific value ranging from approximately 3000 to 4400 kJ / Nm³. 3 The calorific value of COG ranges from approximately 15,000 to 17,800 kJ / Nm³. 3 The calorific value of LDG ranges from approximately 6000 to 7500 kJ / Nm³. 3 From equation (1), it can be seen that the calorific value H of the mixed gas is... 热值 The range is 3000–17800 kJ / Nm 3 Because the volume of various types of gas changes, the mixing ratio of the gas supplied to the boiler is constantly changing, and the calorific value of the gas will also vary within a certain range at different times. Furthermore, since the gas flow rate can be obtained through a metering system, but the calorific value is unknown, the interval method is more reasonable than the fixed value method for calorific value analysis; the interval method for gas calorific value is expressed as [H...]. min H max The calorific value of the gas supplied to the boiler end of the steel plant cannot be obtained accurately, so it is expressed as a certain range.

[0058] Step 2: Establish a correlation model between the calorific value of coal gas and boiler efficiency; use thermal efficiency to measure the boiler's operating performance, and then evaluate the boiler's energy efficiency.

[0059] As can be seen from the boiler operating principle, the boiler thermal efficiency is the ratio of the effective heat of the boiler to the total heat brought in by the raw materials, as shown in equation (2). Boiler thermal efficiency is the most effective indicator for measuring the boiler operating effect. Therefore, this invention still uses this indicator as a guide and improves it by integrating the method proposed in this invention to adapt to the operating characteristics of steel plant boilers.

[0060]

[0061] In the formula: η represents the thermal efficiency of the boiler;

[0062] Q 有效 Indicates the effective heat capacity of the boiler;

[0063] Q 送入 This indicates the total heat carried into the boiler by the fuel fed into the furnace;

[0064] h 蒸汽 h 给水 These represent the enthalpy values ​​of boiler steam and feedwater, respectively, which can be obtained by measuring the flow rate, temperature, and pressure of steam and feedwater.

[0065] Q 送入 =V 煤气 ×H 热值 (3)

[0066] In the formula: V 煤气 This indicates the volume of gas supplied to the boiler.

[0067] H 热值 This represents the calorific value of the gas fed into the boiler. Since the exact calorific value of the gas cannot be determined, the calorific value interval method is used instead and included in the calculation.

[0068] From equations (2) and (3), it can be seen that the calorific value of the gas is inversely proportional to the boiler efficiency. In the boiler efficiency calculation process, based on the actual situation of steel enterprises, the enthalpy values ​​of steam and feedwater in self-owned power plant boilers can be directly measured. The lowest and highest values ​​of the gas calorific value range are taken respectively and used in equation (2) to obtain the corresponding boiler thermal efficiency range. The boiler gas supply volume V... i At that time, relative to the calorific value range of coal gas [H min H max The boiler thermal efficiency range was calculated to be [η]. min ,η max ],like Figure 3 As shown. Under the same boiler gas load and the same boiler steam, feedwater flow rate, temperature, and pressure, when the calorific value of the gas is H... max At that time, it can be seen from equation (2) that the efficiency is the lowest, with η min This indicates that when the calorific value of the gas is H... min From equation (2), it can be seen that the efficiency is maximized by η. max Indicates, such as Figure 3 As shown.

[0069] Step 3: Calculate the range of optimal thermal efficiency for the boiler using interval analysis.

[0070] Using historical data analysis, the gas supply volume V and the corresponding boiler efficiency for the most recent N days were statistically analyzed (using the efficiency interval method). The distribution of boiler thermal efficiency for different gas supply volumes V is shown below. Figure 4 As shown (statistics over 30 days, displayed in daily units).

[0071] The method provided by this invention calculates boiler efficiency over a statistical period. It addresses situations where the probability of boiler efficiency exceeding 90% occurs within a 30-day statistical period. Figure 4 Based on the statistical data shown, the following calculation process can be established to address the issue:

[0072] 1. Figure 4 The 30 statistical periods shown are respectively denoted by V i It indicates that, with V i The corresponding boiler efficiency is η i , i = {1, 2, ..., 30}.

[0073] 2. Each V i The corresponding boiler thermal efficiency line segments are used to determine the maximum efficiency values. and minimum value like Figure 3 As shown, this forms a 30-day gas supply V. i The set of maximum and minimum efficiency values ​​at any given time

[0074] 3. Order and Representing sets The maximum and minimum values.

[0075] 4. Order and Representing sets The maximum and minimum values.

[0076] 5. Order In the formula, a% represents the percentage;

[0077] make In the formula, b% represents the percentage.

[0078] 6. Let a% = b% = 90%, then the new efficiency range [MIN, MAX] is the amount of gas supplied to the boiler system, V. i At that time, the most reasonable efficiency range is reached, and the incidence rate is over 90%.

[0079] like Figure 5 The shaded area [MIN, MAX] represents the boiler's optimal energy efficiency zone. This corresponds to a boiler gas supply of V. i At that time, the boiler efficiency is within its optimal range, which is the optimized operating range for the boiler. However, due to frequent fluctuations in the gas fuel supply of steel plants and the lack of calorific value measurement, there is insufficient basis for determining boiler operation. Analysis shows that... Figure 5 Although the shaded area is slightly lower than the boiler efficiency design value and the boiler efficiency of thermal power plants, the boilers of steel plants are already in a high-efficiency range and are operating well in this area.

[0080] Step 4: Determine the operating range of the boiler.

[0081] Based on the actual operation of the boiler, the fitted boiler efficiency change curve is as follows: Figure 6 As shown.

[0082] In the figure, γ represents the ratio of the actual fuel supply of the boiler to the rated fuel quantity, and its calculation process is as follows:

[0083]

[0084] η b (γ) = -74.36γ 2 + 162.58γ + 3.15 (5)

[0085] In the formula: v b represents the fuel quantity supplied to boiler b;

[0086] represents the standard value of the fuel quantity supplied to boiler b.

[0087] The calorific value of the gas supplied to the boiler is unknown. It can be seen from the analysis that the boiler efficiency corresponding to each fuel load will form an interval (this process has been introduced before), and key reference is Figure 5 as shown. Combining formula (5) with the boiler efficiency corresponding to each fuel load, they jointly constitute the best range of the dynamic fluctuation of the boiler efficiency in the steel plant, as Figure 7 shown. Figure 7 The shaded area in is the high - energy - efficiency range in the actual production process of the boiler, and this area is the green interval for the boiler operation.

[0088] Step Five: Boiler energy - efficiency evaluation.

[0089] For any boiler in the steel enterprise, call formula (2) to calculate the boiler efficiency η 锅炉 , if η 锅炉 ∈[MAX, MIN], that is, within the shaded range between the MAX line and the MIN line as Figure 7 shown, it means the boiler operates reasonably; if η 锅炉 > MAX line, it means the thermal efficiency of the boiler at this moment is relatively high, but it cannot maintain long - term stability, and it will soon fluctuate and drop. Instead of the boiler operating efficiently, it will cause fluctuations in the boiler operating conditions, which is not conducive to the boiler operation; while if η 锅炉 < MIN line, it means the boiler operates inefficiently, and a prompt message needs to be sent to the system to remind the enterprise gas dispatching to make improvements, so as to ensure the efficient operation of the steel - plant boiler.

[0090] Embodiment

[0091] Taking the 220t boiler of a self - contained power plant in a steel plant as an example, the types of gas used by the boiler are blast - furnace gas, and the rated fuel load, actual fuel load, boiler efficiency, etc. of the boiler are shown in Table 1.

[0092] Table 1 Boiler case data table

[0093]

[0094] By applying the calculation and analysis process of this invention to this blast furnace, the high-efficiency green operating range of the boiler was obtained, as follows: Figure 8 As shown in the figure, the boiler's operating status and performance are analyzed and diagnosed in real time through the green zone representing high energy efficiency (shaded area), guiding boiler energy efficiency optimization and improvement efforts.

Claims

1. A practical energy efficiency evaluation method for boilers in self-owned power plants of integrated iron and steel enterprises, characterized in that, It includes the following steps: Step 1: Analysis of the calorific value variation of the supplied boiler gas; the calorific value of the gas is affected by the supply of BFG, COG, and LDG and their corresponding lower heating values; and while the gas flow rate can be obtained through a metering system, the calorific value is unknown. Therefore, the interval method is more reasonable than the fixed value method for calorific value analysis; the interval method for gas calorific value is expressed as [H min H max The calorific value of the gas supplied to the boiler end of the steel plant cannot be obtained accurately, and is expressed as a certain range. Step 2: Establish a correlation model between the calorific value of gas and the boiler thermal efficiency; use the boiler thermal efficiency to measure the operation effect of the boiler, and then evaluate the boiler energy efficiency; Step 3: Calculate the range of the optimized thermal efficiency of the boiler by the interval analysis method; use the historical data analysis method to count the gas supply volume V and the corresponding boiler thermal efficiency in the recent N days, obtain the distribution of the boiler thermal efficiency when the gas supply volume is V, and calculate the occurrence probability of the boiler thermal efficiency within the statistical time period above 90%, so as to determine a new efficiency interval [MIN, MAX]. The new efficiency interval [MIN, MAX] is the most reasonable efficiency interval when the gas supply volume of the boiler system is V, and the incidence rate accounts for more than 90%. The new efficiency interval [MIN, MAX] is the range of the optimized thermal efficiency of the boiler when the gas supply volume is V; Step 4: Determine the boiler operation range; according to the actual operation process of the boiler, fit the curve of the boiler thermal efficiency changing with γ, where γ represents the ratio of the actual fuel supply volume of the boiler to the rated fuel volume. Combine the fitted curve of the boiler thermal efficiency changing with γ with the range of the optimized thermal efficiency of the boiler to obtain the best range of the dynamic fluctuation of the boiler thermal efficiency. The best range is the range between the MIN line and the MAX line. The MIN line is the curve of MIN changing with γ, and the MAX line is the curve of MAX changing with γ; Step 5: Evaluate the boiler energy efficiency; if the boiler thermal efficiency η is within the range between the MAX line and the MIN line, it means that the boiler operates reasonably; if η > MAX line, it means that the thermal efficiency of the boiler at this moment is relatively high, but it cannot maintain long-term stability, and it will soon fluctuate and decrease. Not only is the boiler operation not efficient, but it also causes fluctuations in the boiler operating conditions, which is not conducive to the operation of the boiler; if η < MIN line, it means that the boiler operates inefficiently, and a prompt message needs to be sent to the system to remind the enterprise's gas dispatching to make improvements, so as to ensure the efficient operation of the steel plant boiler.

2. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 1, characterized in that: In Step 1, the calculation of the gas calorific value is shown in Equation (1): In the formula: V BFG V COG V LDG These represent the flow rates of BFG, COG, and LDG supplied to the boiler, respectively. H BFG H COG H LDG These represent the lower heating values ​​of BFG, COG, and LDG, respectively.

3. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 2, characterized in that: BFG calorific value range: 3000~4400kJ / Nm 3 The calorific value of COG ranges from 15,000 to 17,800 kJ / Nm³. 3 The calorific value of LDG ranges from 6000 to 7500 kJ / Nm³. 3 From equation (1), it can be seen that the calorific value H of the mixed gas is... 热值 The range is 3000–17800 kJ / Nm 3 Since the volume of various types of gas is changing, the mixing ratio of the gas supplied to the boiler is constantly changing, and the calorific value of the gas will also vary within a certain range at different times.

4. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 1, characterized in that: In Step 2, according to the boiler operation process principle, the boiler thermal efficiency is the ratio of the effective heat of the boiler to the total heat brought into the boiler by the fuel entering the furnace, as shown in Equation (2): In the formula: η represents the thermal efficiency of the boiler; Q 有效 Indicates the effective heat capacity of the boiler; Q 送入 This indicates the total heat carried into the boiler by the fuel fed into the furnace; h 蒸汽 h 给水 These represent the total enthalpy values ​​of steam and feedwater corresponding to the total amount of boiler fuel, respectively.

5. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 4, characterized in that: The total heat Q brought into the boiler by the fuel is 送入 The calculation formula is as follows: Q 送入 =V 煤气 ×H 热值 (3) In the formula: V 煤气 This indicates the volume of gas supplied to the boiler. H 热值 This indicates the calorific value of the gas fed into the boiler.

6. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 5, characterized in that: It can be seen from Equation (2) and Equation (3) that the gas calorific value and the boiler thermal efficiency have an inverse proportional law influence; in the process of calculating the boiler thermal efficiency, according to the actual situation of the steel enterprise, the enthalpy values of the steam and feed water of the self-provided power plant boiler can be directly measured; the minimum and maximum values of the gas calorific value interval are respectively taken to participate in the calculation of Equation (2) to obtain the corresponding boiler thermal efficiency interval.

7. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 1, characterized in that: In Step 3, calculate the boiler thermal efficiency situation within the statistical time period; within the statistical time period of 30 days, the occurrence probability of the boiler thermal efficiency is above 90%; for the statistical situation, establish the following calculation process to solve it: ①During the 30-day statistical period, the gas supply V and the thermal efficiency of 30 boilers were respectively expressed as η. i Let i = {1, 2, ..., 30}; ② Thermal efficiency η of each boiler i Take the maximum value respectively and minimum value Forming a set of maximum boiler thermal efficiency values ​​when the gas supply is V and minimum set ③ Order and Representing sets respectively The maximum and minimum values; ④ Order and Representing sets respectively The maximum and minimum values; ⑤ Order In the formula, a% represents the percentage; make In the formula, b% represents the percentage; ⑥ Let a% = b% = 90%, then the result of calculating the range of the optimized efficiency of the boiler by the interval analysis method - the new efficiency interval [MIN, MAX] is the most reasonable efficiency interval when the gas supply volume of the boiler system is V, and the incidence rate accounts for more than 90%.

8. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 1, characterized in that: In step four, γ represents the ratio of the actual fuel supply to the rated fuel supply of the boiler, and its calculation process is as follows: or b (c)=-74.36c 2 +162.58c+3.15 (5) In the formula: v b This indicates the amount of fuel supplied to boiler b; This represents the standard value for the amount of fuel supplied to boiler b.

9. The practical energy efficiency evaluation method for self-owned power plant boilers in integrated iron and steel enterprises according to claim 4, characterized in that: In Step 5, for the gas load of any boiler in the steel enterprise, the boiler thermal efficiency η is calculated by using Equation (2). 锅炉 , if η 锅炉 ∈[MAX, MIN], it means the boiler is operating reasonably; if η 锅炉 > the MAX line, it means the thermal efficiency of the boiler at this moment is relatively high, but it cannot maintain long-term stability, and will soon fluctuate and drop. Not only is the boiler operation not efficient, but it also causes fluctuations in the boiler conditions, which is not conducive to the boiler operation; while if η 锅炉 < the MIN line, it means the boiler is operating inefficiently, and a prompt message needs to be sent to the system to remind the enterprise's gas dispatching to make improvements to ensure the efficient operation of the steel plant boiler.

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