Method, system and equipment for reducing temperature of flue gas at outlet of boiler furnace

Abstract

The invention provides a method, system and equipment for reducing boiler furnace outlet smoke temperature, and the method comprises the steps: carrying out a boiler thermal state test based on boiler tail reinlet smoke temperature, and determining a to-be-adjusted SOFA air door as an adjustment object; under the condition that the total air volume of the boiler is kept unchanged, the SOFA air volume of an adjustment object is reduced and the secondary air volume of a main combustion area is increased by utilizing a secondary air volume distribution proportion adjustment strategy; the combustion speed of pulverized coal in a hearth is increased, heat release is accelerated, the flame stroke is shortened, the smoke temperature of an outlet of the hearth is reduced by increasing the temperature of the main combustion area of the boiler, the secondary air volume of the main combustion area is effectively increased by adjusting the opening degree of an SOFA air door, and the air-powder matching optimization effect is improved. The hearth temperature is effectively increased, the hearth outlet temperature is further reduced, and the combustion efficiency and the boiler safety are guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of boiler combustion, and in particular to a method, system and equipment for reducing the flue gas temperature at a boiler furnace outlet. Background Art

[0002] Under the low-nitrogen combustion mode, when the boiler is operating at high load, there is severe oxygen deficiency in the main combustion area, the furnace temperature is low, the air-powder coordination is poor, the coal powder combustion is delayed, and the furnace outlet flue gas temperature generally exceeds the design value, causing the superheater tube screen to overheat, seriously affecting equipment safety.

[0003] Therefore, how to reduce the flue gas temperature at the boiler furnace outlet has become a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0004] The present invention provides a method, system and equipment for reducing the flue gas temperature at a boiler furnace outlet, so as to solve the defects in the prior art that the boiler furnace outlet temperature is too high, resulting in low combustion efficiency and potential safety hazards.

[0005] In a first aspect, the present invention provides a method for reducing the flue gas temperature at a boiler furnace outlet, comprising: Based on the boiler final re-inlet smoke temperature, a boiler hot test is conducted to determine the SOFA damper to be adjusted as the adjustment object; Under the condition of keeping the total air volume of the boiler unchanged, the secondary air volume distribution ratio adjustment strategy is used to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone; The secondary air volume in the main combustion zone is utilized to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

[0006] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, a boiler hot state test is performed based on the flue gas temperature at the end of the boiler inlet, and a SOFA damper to be adjusted is determined as an adjustment object, comprising: Determine the first flue gas temperature and the second flue gas temperature at the boiler end re-entry as the flue gas temperature measuring points; Determine the first opening of the first horn three-layer SOFA damper and the second opening of the second horn three-layer SOFA damper as objects to be selected; By adjusting the first opening and the second opening respectively, detecting the corresponding change amount of the first smoke temperature and the second smoke temperature; When the variation of the first smoke temperature is greater than a preset threshold, determining the first horn three-layer SOFA damper as an adjustment object; When the change in the second smoke temperature is greater than a preset threshold, the second horn three-layer SOFA damper is determined to be an adjustment object.

[0007] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, the first opening and the second opening are adjusted respectively, and the corresponding changes in the first flue gas temperature and the second flue gas temperature are detected, including: The first opening is adjusted from 40% to 0 by gradient, and the first smoke temperature variation curve in the adjustment process is obtained; The second opening is adjusted from 100% to 20% by gradient, and the second smoke temperature variation curve during the adjustment process is obtained; The variation of the first smoke temperature and the variation of the second smoke temperature within a preset time period are determined by using the first smoke temperature variation curve and the second smoke temperature variation curve.

[0008] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, under the condition of keeping the total air volume of the boiler unchanged, a secondary air volume distribution ratio adjustment strategy is used to reduce the SOFA air volume of the adjustment object, including: Dynamically evaluate the current combustion status in the boiler furnace based on the current furnace outlet temperature; Based on the combustion state and the target furnace outlet temperature, a time series prediction model is used to predict the air volume demand within a preset time period; The air volume transfer efficiency is used to dynamically compensate the air volume demand, and the SOFA damper angle adjustment range is obtained to adjust the opening of the adjustment object.

[0009] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, the method dynamically evaluates the current combustion state in the boiler furnace based on the current furnace outlet temperature, including: Divide the furnace into the main reaction layer, transition mixing layer and burnout suppression layer; The current combustion state in the boiler furnace is obtained by utilizing the positive correlation between the air volume demand and the temperature gradient of the main reaction layer, the negative correlation between the air volume demand and the carbon monoxide concentration of the transition mixing layer, and the exponential correlation between the air volume demand and the nitrogen oxide generation rate of the burnout suppression layer.

[0010] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, the method utilizes the positive correlation between the air volume demand of the main reaction layer and the temperature gradient, the negative correlation between the air volume demand of the transition mixing layer and the carbon monoxide concentration, and the correlation between the air volume demand of the burnout suppression layer and the generation rate index of nitrogen oxides to obtain the current combustion state in the boiler furnace, including: The combustion intensity distribution is obtained in real time through the temperature gradient monitoring array of the main reaction layer, and the air volume demand coefficient is calculated using the exponential weighted sliding average method to characterize the oxygen diffusion demand; The carbon monoxide concentration field in the transitional mixing layer is measured using the TDLAS laser detection grid, and the mixing efficiency requirement is dynamically corrected through an inverse proportional adaptive function. Combined with the online identification model of nitrogen oxide generation rate in the burnout suppression layer, the hyperbolic tangent activation function is used to quantify the air volume suppression demand in the burnout zone. The air volume demand coefficient, the inverse proportional adaptive function and the hyperbolic tangent activation function are dynamically integrated through entropy weight method-grey correlation analysis to generate a comprehensive index of combustion state.

[0011] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, the comprehensive combustion state index is: CSI=0.45α*(1+ )+0.35γ*ln(1+|ΔT|)+0.2|α-γ|; Among them, α represents the air volume demand coefficient, represents the inverse proportional adaptive function, γ represents the hyperbolic tangent activation function, and ΔT represents the characteristic temperature difference between the main reaction layer and the burnout suppression layer.

[0012] According to a method for reducing the flue gas temperature at a boiler furnace outlet provided by the present invention, the air volume transfer efficiency is used to dynamically compensate the air volume demand to obtain the SOFA damper angle adjustment range, including: The air volume transfer efficiency is calculated by real-time monitoring of the temperature gradient, turbulence intensity and oxygen concentration distribution in the main combustion zone and SOFA zone; The air volume transfer efficiency is utilized in combination with the combustion efficiency deviation to dynamically generate the SOFA damper angle adjustment amount.

[0013] In a second aspect, the present invention further provides a system for reducing the flue gas temperature at a boiler furnace outlet, comprising: A determination module, used to perform a boiler hot state test based on the boiler final re-inlet smoke temperature, and determine the SOFA damper to be adjusted as the adjustment object; An adjustment module is used to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone by using a secondary air volume distribution ratio adjustment strategy while keeping the total air volume of the boiler unchanged; The lifting module is used to utilize the secondary air volume in the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

[0014] In a third aspect, the present invention also provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the method for reducing the flue gas temperature at the boiler furnace outlet as described in any one of the above methods is implemented.

[0015] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the methods described above for reducing the flue gas temperature at a boiler furnace outlet.

[0016] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the methods described above for reducing the flue gas temperature at a boiler furnace outlet.

[0017] The present invention provides a method, system and equipment for reducing the flue gas temperature at the boiler furnace outlet. The method includes: performing a boiler hot test based on the boiler final inlet flue gas temperature, determining a SOFA damper to be adjusted as an adjustment object; under the condition of keeping the total air volume of the boiler unchanged, utilizing a secondary air volume distribution ratio adjustment strategy to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone; utilizing the secondary air volume of the main combustion zone to increase the pulverized coal combustion speed in the furnace, accelerate heat release and shorten the flame stroke, reduce the furnace outlet flue gas temperature by increasing the temperature of the boiler main combustion zone, and effectively increase the secondary air volume of the main combustion zone by adjusting the opening of the SOFA damper, thereby improving the air-powder coordination optimization effect, effectively increasing the furnace temperature, and then reducing the furnace outlet temperature, thereby ensuring combustion efficiency and boiler safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a flow chart of a method for reducing the flue gas temperature at a boiler furnace outlet provided in this embodiment; Figure 2 is a schematic diagram of the structure of a system for reducing the flue gas temperature at a boiler furnace outlet provided in this embodiment; Figure 3 It is a schematic diagram of the structure of the electronic device provided in this embodiment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. 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] Figure 1 It is a flow chart of a method for reducing the flue gas temperature at the boiler furnace outlet provided in this embodiment.

[0022] like Figure 1 As shown, a method for reducing the flue gas temperature at a boiler furnace outlet provided by an embodiment of the present invention mainly comprises the following steps: 101. Carry out boiler hot test based on the flue gas temperature at the end of boiler re-entry and determine the SOFA damper to be adjusted as the adjustment object.

[0023] In a specific implementation process, the equipment reliability is improved by lowering the flue gas temperature at the boiler furnace outlet and controlling the temperature of the superheater and reheater tube screens. Therefore, it is first necessary to determine which temperature is used as the standard for subsequent control. In this embodiment, the first flue gas temperature at the boiler end re-inlet, i.e., flue gas temperature A, and the second flue gas temperature, i.e., flue gas temperature B, are used as flue gas temperature measurement points, and the first opening of the three-layer SOFA damper at the first horn and the second opening of the three-layer SOFA damper at the second horn are used as objects to be selected. Among them, the first horn and the second horn can be any one of horns 1, 2, 3, and 4. In this embodiment, horns 2 and 4 are preferably used for hot state experiments.

[0024] Specifically, taking the load of 300MW of unit 6 as an example, the opening of the three-layer SOFA damper at corner 4 is 40%, the opening of the three-layer SOFA damper at corner 1 is 100%, the A and B flue gas temperatures at the boiler end re-inlet are 751.1℃ and 820.8℃, and the first and second flue gas temperatures at the boiler end re-inlet are used as the measuring points for the furnace outlet flue gas temperature.

[0025] Then adjust the first opening and the second opening respectively, detect the corresponding changes in the first smoke temperature and the second smoke temperature, adjust the first opening from 40% to 0, and obtain the first smoke temperature change curve during the adjustment process; adjust the second opening from 100% to 20%, and obtain the second smoke temperature change curve during the adjustment process. Through the first smoke temperature change curve and the second smoke temperature change curve, determine the changes in the first smoke temperature and the second smoke temperature change curve within the preset time period. You can also collect once before adjustment, and collect again after a certain period of time.

[0026] When the change in the first smoke temperature is greater than a preset threshold, the first horn three-layer SOFA damper is determined to be the adjustment object; when the change in the second smoke temperature is greater than the preset threshold, the second horn three-layer SOFA damper is determined to be the adjustment object.

[0027] Correspondingly, the first opening was adjusted from 40% gradient to 0, and the flue gas temperatures at the boiler end inlet A and B were reduced from 751.1 / 820.8℃ to 739.0 / 801.0℃. As a result of the adjustment, the flue gas temperature on the A side decreased by 12.1℃, and the flue gas temperature on the B side decreased by 19.8℃.

[0028] The second opening was adjusted from 100% to 20% by gradient, and the flue gas temperatures at the boiler end inlet A and B dropped from 739.0 / 801.0℃ to 732.0 / 795.4℃. The adjustment result was a 7℃ drop on the A side and a 5.6℃ drop on the B side.

[0029] After two adjustments, the flue gas temperatures at the boiler's end re-inlet A and B dropped from 751.1 / 820.8℃ to 732.0 / 795.4℃, the flue gas temperature on the boiler's end re-inlet A side dropped by 19.1℃, and the flue gas temperature on the B side dropped by 25.4℃. Both the end re-inlet flue gas temperatures dropped significantly, indicating that the adjustment is effective.

[0030] Therefore, the No. 4 corner three-layer SOFA damper and the No. 1 corner three-layer SOFA damper are selected as the adjustment objects.

[0031] 102. Under the condition of keeping the total air volume of the boiler unchanged, the secondary air volume distribution ratio adjustment strategy is used to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion area.

[0032] Under the condition of keeping the total air volume of the boiler unchanged, the first choice is to reduce the opening of the three-layer SOFA damper at angle 4 to reduce the SOFA air volume, and the second choice is to reduce the opening of the three-layer SOFA damper at angle 1 to reduce the SOFA air volume. Reducing the SOFA air volume means increasing the secondary air volume in the main combustion area, optimizing the coordination of air and powder in the corresponding area, significantly increasing the furnace temperature, and achieving the purpose of reducing the smoke temperature at the furnace outlet.

[0033] 103. Utilize the secondary air volume in the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame travel, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler's main combustion zone.

[0034] Since the secondary air volume in the main combustion zone is increased, combustion will be more fully carried out in the main combustion zone, thereby increasing the combustion speed. Since the temperature of the main combustion zone of the furnace is increased, the flue gas temperature at the furnace outlet is automatically reduced accordingly.

[0035] Furthermore, on the basis of the above-mentioned embodiments, in this embodiment, while keeping the total air volume of the boiler unchanged, a secondary air volume allocation ratio adjustment strategy is used to reduce the SOFA air volume of the adjustment object, including: dynamically evaluating the current combustion state in the boiler furnace based on the current furnace outlet temperature; predicting the air volume demand within a preset time period based on the combustion state and the target furnace outlet temperature using a time series prediction model; and dynamically compensating for the air volume demand using the air volume transfer efficiency to obtain the SOFA damper angle adjustment range to adjust the opening of the adjustment object.

[0036] By dynamically coupling the temperature field, component field, flow field and combustion efficiency, the limitations of traditional single parameter control are broken. Autonomous decision-making optimization of air volume distribution is achieved through DRL to solve the problem of multi-objective conflicts. A nonlinear coupling relationship between the main combustion zone and the SOFA zone is established to ensure precise control under the conservation of total air volume. The ash melting point characteristics are incorporated into the real-time control logic to achieve dual-objective optimization of safety and energy efficiency.

[0037] Specifically, the furnace is divided into the main reaction layer (1200-1500℃), the transition mixing layer (900-1200℃) and the burnout suppression layer (600-900℃). The current combustion state in the boiler furnace is obtained by using the positive correlation between the air volume demand of the main reaction layer and the temperature gradient, the negative correlation between the air volume demand of the transition mixing layer and the carbon monoxide concentration, and the correlation between the air volume demand of the burnout suppression layer and the generation rate index of nitrogen oxides.

[0038] The combustion intensity distribution is obtained in real time through the main reaction layer temperature gradient monitoring array ∂T / ∂x, and the air volume demand coefficient is calculated using the exponential weighted moving average method to characterize the oxygen diffusion demand, as shown in (1); α=∫(∂T / ∂x* )dx(1); in, represents the combustion front position, L represents the characteristic length, ∂T / ∂x represents the temperature gradient monitoring array, Indicates the current front position.

[0039] The TDLAS laser detection grid is used to measure the carbon monoxide concentration field in the transition mixing layer, and the mixing efficiency requirement is dynamically corrected by an inverse proportional adaptive function, as shown in (2): β=1 / (1+0.5* )(2) in, Represents the carbon monoxide concentration field.

[0040] Combined with the online identification model of the nitrogen oxide generation rate in the burnout suppression layer, the hyperbolic tangent activation function is used to quantify the air volume suppression demand in the burnout zone, as shown in (3): γ=tanh(0.01*∫(d[NOx] / dt)dt)(3) Wherein, d[NOx] / dt represents the online identification model of nitrogen oxide generation rate.

[0041] The entropy weight method-grey correlation analysis dynamically integrates the air volume demand coefficient, the inverse proportional adaptive function and the hyperbolic tangent activation function to generate the combustion state comprehensive index, which is (4): CSI=0.45α*(1+ )+0.35γ*ln(1+|ΔT|)+0.2|α-γ|(4) Among them, α represents the air volume demand coefficient, represents the inverse proportional adaptive function, γ represents the hyperbolic tangent activation function, and ΔT represents the characteristic temperature difference between the main reaction layer and the burnout suppression layer.

[0042] The current combustion state in the boiler furnace determined in this way can achieve cross-scale mapping from local parameters to global combustion state, upgrading traditional single-point monitoring to multi-physical field coupled diagnosis of gradient field-chemical reaction kinetics-fluid mixing effect. The diagnostic error is reduced by 62% compared with traditional methods, ensuring the accuracy of combustion state detection.

[0043] Furthermore, in this embodiment, the air volume transfer efficiency is used to dynamically compensate the air volume demand and obtain the SOFA damper angle adjustment range, including: by real-time monitoring the temperature gradient (∂T / ∂x), turbulence intensity (Tu) and oxygen concentration distribution between the main combustion zone and the SOFA zone, the air volume transfer efficiency is calculated, such as (5): η=0.8*exp(-0.05*ΔT)*(1+0.2*Tu) (5) Where ΔT represents the characteristic temperature difference between the main reaction layer and the burnout suppression layer, and Tu represents the turbulence intensity.

[0044] The air volume transfer efficiency is used in combination with the combustion efficiency deviation to dynamically generate the SOFA damper angle adjustment, as shown in (6): Δθ= *Δη*(1-exp(-t / τ))(6) in, is the proportional gain, ranging from 0.5 to 1.2, τ is the time constant, ranging from 10 seconds to 30 seconds, and t represents time.

[0045] It effectively ensures that the adjustment range is always in the safe-efficient range, achieving precise compensation of SOFA air volume and dynamic balance of combustion state.

[0046] Based on the same general inventive concept, the present invention also protects a system for reducing the flue gas temperature at a boiler furnace outlet. The system for reducing the flue gas temperature at a boiler furnace outlet described below and the method for reducing the flue gas temperature at a boiler furnace outlet described above can refer to each other.

[0047] Figure 2 It is a schematic diagram of the structure of the system for reducing the flue gas temperature at the boiler furnace outlet provided in this embodiment.

[0048] like Figure 2 As shown, this embodiment provides a system for reducing the flue gas temperature at a boiler furnace outlet, comprising: A determination module 201 is used to perform a boiler hot state test based on the boiler final re-inlet smoke temperature and determine the SOFA damper to be adjusted as an adjustment object; The adjustment module 202 is used to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone by using the secondary air volume distribution ratio adjustment strategy while keeping the total air volume of the boiler unchanged; The lifting module 203 is used to utilize the secondary air volume in the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

[0049] Figure 3 It is a schematic diagram of the structure of the electronic device provided in this embodiment.

[0050] like Figure 3 As shown, the electronic device may include: a processor 310, a communication interface 320, a memory 330 and a communication bus 340, wherein the processor 310, the communication interface 320 and the memory 330 communicate with each other through the communication bus 340. The processor 310 may call the logic instructions in the memory 330 to execute a method for reducing the flue gas temperature at the boiler furnace outlet, the method comprising: performing a boiler hot state test based on the boiler final inlet flue gas temperature, determining the SOFA damper to be adjusted as the adjustment object; under the condition of keeping the total air volume of the boiler unchanged, using the secondary air volume distribution ratio adjustment strategy, reducing the SOFA air volume of the adjustment object and increasing the secondary air volume of the main combustion zone; using the secondary air volume of the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate the heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

[0051] In addition, the logic instructions in the above-mentioned memory 330 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0052] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the method for reducing the flue gas temperature at the boiler furnace outlet provided by the above-mentioned methods, and the method includes: conducting a boiler hot test based on the boiler end-reinlet flue gas temperature, and determining the SOFA damper to be adjusted as the adjustment object; while keeping the total air volume of the boiler unchanged, using the secondary air volume distribution ratio adjustment strategy to reduce the SOFA air volume of the adjustment object and increase the secondary air volume in the main combustion zone; using the secondary air volume in the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

[0053] On the other hand, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to execute the method for reducing the flue gas temperature at the boiler furnace outlet provided by the above-mentioned methods, the method comprising: conducting a boiler hot test based on the boiler final inlet flue gas temperature, and determining the SOFA damper to be adjusted as the adjustment object; under the condition of keeping the total air volume of the boiler unchanged, using the secondary air volume distribution ratio adjustment strategy to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone; using the secondary air volume of the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

[0054] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0055] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for reducing the flue gas temperature at a boiler furnace outlet, characterized in that: include: Based on the boiler final re-inlet smoke temperature, a boiler hot test is conducted to determine the SOFA damper to be adjusted as the adjustment object; Under the condition of keeping the total air volume of the boiler unchanged, the secondary air volume distribution ratio adjustment strategy is used to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone; The secondary air volume in the main combustion zone is utilized to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

2. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 1, characterized in that: The boiler hot state test is performed based on the boiler final re-inlet smoke temperature to determine the SOFA damper to be adjusted as the adjustment object, including: Determine the first flue gas temperature and the second flue gas temperature at the boiler end re-entry as the flue gas temperature measuring points; Determine the first opening of the first horn three-layer SOFA damper and the second opening of the second horn three-layer SOFA damper as objects to be selected; By adjusting the first opening and the second opening respectively, detecting the corresponding change amount of the first smoke temperature and the second smoke temperature; When the variation of the first smoke temperature is greater than a preset threshold, determining the first horn three-layer SOFA damper as an adjustment object; When the change in the second smoke temperature is greater than a preset threshold, the second horn three-layer SOFA damper is determined to be an adjustment object.

3. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 2, characterized in that: The step of respectively adjusting the first opening and the second opening and detecting the corresponding changes in the first smoke temperature and the second smoke temperature comprises: The first opening is adjusted from 40% to 0 by gradient, and the first smoke temperature variation curve in the adjustment process is obtained; The second opening is adjusted from 100% to 20% by gradient, and the second smoke temperature variation curve during the adjustment process is obtained; The variation of the first smoke temperature and the variation of the second smoke temperature within a preset time period are determined by using the first smoke temperature variation curve and the second smoke temperature variation curve.

4. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 1, characterized in that: Under the condition of keeping the total air volume of the boiler unchanged, the secondary air volume distribution ratio adjustment strategy is used to reduce the SOFA air volume of the adjustment object, including: Dynamically evaluate the current combustion status in the boiler furnace based on the current furnace outlet temperature; Based on the combustion state and the target furnace outlet temperature, a time series prediction model is used to predict the air volume demand within a preset time period; The air volume transfer efficiency is used to dynamically compensate the air volume demand, and the SOFA damper angle adjustment range is obtained to adjust the opening of the adjustment object.

5. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 4, characterized in that: The method of dynamically evaluating the combustion state in the current boiler furnace based on the current furnace outlet temperature includes: Divide the furnace into the main reaction layer, transition mixing layer and burnout suppression layer; The current combustion state in the boiler furnace is obtained by utilizing the positive correlation between the air volume demand and the temperature gradient of the main reaction layer, the negative correlation between the air volume demand and the carbon monoxide concentration of the transition mixing layer, and the exponential correlation between the air volume demand and the nitrogen oxide generation rate of the burnout suppression layer.

6. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 4, characterized in that: The method utilizes the positive correlation between the air volume demand of the main reaction layer and the temperature gradient, the negative correlation between the air volume demand of the transition mixing layer and the carbon monoxide concentration, and the correlation between the air volume demand of the burnout suppression layer and the generation rate index of nitrogen oxides to obtain the current combustion state in the boiler furnace, including: The combustion intensity distribution is obtained in real time through the temperature gradient monitoring array of the main reaction layer, and the air volume demand coefficient is calculated using the exponential weighted sliding average method to characterize the oxygen diffusion demand; The TDLAS laser detection grid is used to measure the carbon monoxide concentration field in the transition mixing layer, and the mixing efficiency requirement is dynamically corrected through an inverse proportional adaptive function. Combined with the online identification model of nitrogen oxide generation rate in the burnout suppression layer, the hyperbolic tangent activation function is used to quantify the air volume suppression demand in the burnout zone. The air volume demand coefficient, the inverse proportional adaptive function and the hyperbolic tangent activation function are dynamically integrated through entropy weight method-grey correlation analysis to generate a comprehensive combustion state index.

7. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 6, characterized in that: The combustion state comprehensive index is: CSI=0.45a*(1+ )+0.35γ*ln(1+|ΔT|)+0.2|α-γ|; Among them, α represents the air volume demand coefficient, represents the inverse proportional adaptive function, γ represents the hyperbolic tangent activation function, and ΔT represents the characteristic temperature difference between the main reaction layer and the burnout suppression layer.

8. The method for reducing the flue gas temperature at the boiler furnace outlet according to claim 4, characterized in that: The air volume transfer efficiency is used to dynamically compensate the air volume demand to obtain the SOFA damper angle adjustment range, including: The air volume transfer efficiency is calculated by real-time monitoring of the temperature gradient, turbulence intensity and oxygen concentration distribution in the main combustion zone and SOFA zone; The air volume transfer efficiency is utilized in combination with the combustion efficiency deviation to dynamically generate the SOFA damper angle adjustment amount.

9. A system for reducing the flue gas temperature at a boiler furnace outlet, characterized in that: include: A determination module, used to perform a boiler hot state test based on the boiler final re-inlet smoke temperature, and determine the SOFA damper to be adjusted as the adjustment object; An adjustment module is used to reduce the SOFA air volume of the adjustment object and increase the secondary air volume of the main combustion zone by using a secondary air volume distribution ratio adjustment strategy while keeping the total air volume of the boiler unchanged; The lifting module is used to utilize the secondary air volume in the main combustion zone to increase the coal powder combustion speed in the furnace, accelerate heat release and shorten the flame stroke, and reduce the flue gas temperature at the furnace outlet by increasing the temperature of the boiler main combustion zone.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for reducing the flue gas temperature at the boiler furnace outlet as described in any one of claims 1 to 8 is implemented.

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