CN-122015119-A - Coal-fired boiler optimal control method and system based on three-dimensional combustion radiant energy signals in furnace

CN122015119ACN 122015119 ACN122015119 ACN 122015119ACN-122015119-A

Abstract

The invention relates to the technical field of combustion control of coal-fired boilers, and discloses an optimization control method and system of a coal-fired boiler based on a three-dimensional combustion radiant energy signal in the boiler. The method comprises the steps of collecting radiation images through flame image detectors around a hearth, reconstructing a three-dimensional temperature field, extracting radiation energy signals by combining the three-dimensional temperature field and the radiation images, compensating deviation, establishing an association relation between the radiation energy signals and unit load, fuel characteristics and air supply quantity, determining and combining optimized control parameters of fuel characteristics to optimize the fuel quantity and the air supply quantity based on the association relation and the deviation between the radiation energy and a load instruction, and adjusting combustion according to the optimized control parameters to enable the heat release quantity in the hearth to be matched with the load demand. The method improves the accuracy and stability of the combustion control of the coal-fired boiler, enhances the load adaptability of the unit and the coal type adaptation capability, improves the combustion efficiency and reduces the pollutant emission.

Inventors

CHEN XUESHUO
TANG GUANGTONG
WANG CHAOYANG
WANG TIANLONG
JIANG JINGZHI
CUI JIN

Assignees

国网河北省电力有限公司电力科学研究院
国家电网有限公司

Dates

Publication Date: 20260512
Application Date: 20260228

Claims (10)

1. The coal-fired boiler optimal control method based on the three-dimensional combustion radiant energy signal in the furnace is characterized by comprising the following steps of: s1, acquiring radiation image information of combustion flame in a coal-fired boiler through flame image detectors arranged around a hearth of the coal-fired boiler, and reconstructing a three-dimensional temperature field in the boiler based on the radiation image information; s2, extracting an internal combustion radiation energy signal of the furnace according to the three-dimensional temperature field and the radiation image information, and performing compensation treatment on the radiation energy signal to eliminate signal deviation caused by dust accumulation, coking and working condition fluctuation of the detector; S3, establishing an association relation between the radiant energy signal and unit operation parameters, wherein the unit operation parameters comprise unit load, fuel characteristics and air supply quantity; S4, determining optimal control parameters of fuel quantity and air supply quantity based on the association relation and deviation of the radiant energy signals and a unit load instruction, and optimizing the optimal control parameters based on fuel characteristics; and S5, adjusting the fuel supply quantity and the air supply quantity of the coal-fired boiler according to the optimized control parameters so as to enable the heat release quantity in the furnace to be matched with the load demand of the unit.
2. The method of claim 1, wherein the reconstructing of the three-dimensional temperature field comprises: And excavating heat radiation transfer information contained in the radiation image information by adopting a DRESOR method, establishing the association between the heat radiation transfer information and the temperature of a combustion medium and the spatial distribution of a heat radiation source, and reconstructing the three-dimensional temperature field from the radiation image information by combining a corrected Tikhonov regularization method.
3. The method of claim 1, wherein extracting the radiant energy signal comprises: Calculating an initial radiant energy signal based on Stefin-Boltzmann's law in combination with temperature data of the three-dimensional temperature field, or calculating the initial radiant energy signal by gray values of the radiation image information; performing range conversion on the initial radiant energy signal by taking the actual power of the unit as a reference, and screening the radiant energy signal reflecting the actual load change of the unit; The process of compensating the radiant energy signal comprises: and aiming at the stage of severe change of the unit load, carrying out proportional correction based on the linear relation between the initial radiant energy signal and the unit power to finish the compensation processing of the radiant energy signal.
4. The method of claim 3, wherein prior to scaling the initial radiant energy signal based on the aggregate real power, further comprising: calculating a first deviation value between the initial radiant energy signals obtained based on the three-dimensional temperature field and the radiant image information, and judging whether the deviation value exceeds a deviation threshold value; If the first deviation value does not exceed the deviation threshold value, taking the average value of the two initial radiant energy signals as a final initial radiant energy signal; And if the deviation value exceeds the deviation threshold, correcting the initial radiant energy signal obtained based on the radiation image information by taking the initial radiant energy signal obtained based on the three-dimensional temperature field as a reference, and taking the corrected initial radiant energy signal as the initial radiant energy signal for executing range conversion on the initial radiant energy signal by taking the unit actual power as a reference.
5. The method of claim 1, wherein the process of establishing the association of the radiant energy signal with the unit operating parameters comprises: Collecting historical operation data of a unit, wherein the historical operation data comprises historical radiant energy signals under different loads and different fuel characteristics, historical unit loads, historical fuel carbon content and historical air supply quantity data; taking the historical radiant energy signal as an output quantity, and taking the historical unit load, the historical fuel carbon content and the historical air supply quantity as input quantities to establish a second-order transfer function mathematical model; and verifying the accuracy of the second-order transfer function mathematical model through unit operation data in different time periods, adjusting model parameters, and completing the establishment of the association relation between the radiant energy signals and the unit operation parameters.
6. The method of claim 5, wherein after said establishing a second order transfer function mathematical model and before said verifying the accuracy of said second order transfer function mathematical model by unit operation data for different time periods, further comprises: dividing a plurality of load intervals according to unit loads, wherein each load interval corresponds to a group of independent model parameters; Aiming at each load interval, based on historical operation data in the interval, adjusting model parameters of the second-order transfer function mathematical model to obtain an optimized second-order transfer function mathematical model corresponding to each load interval; And integrating all optimized second-order transfer function mathematical models corresponding to the load intervals to form the second-order transfer function mathematical model covering the full load range.
7. The method of claim 1, wherein the determining the optimal control parameters for fuel and air delivery comprises: Determining the total amount of target fuel carbon according to the unit load instruction and the association relation; calculating target air supply quantity by combining the target total fuel carbon quantity based on a preset air-carbon ratio; comparing the radiant energy signal with a target radiant energy signal corresponding to a unit load instruction to obtain a second deviation value; adjusting the fuel supply amount according to the second deviation value to enable the actual fuel carbon total amount to approach the target fuel carbon total amount; And synchronously adjusting the air supply quantity, so that the actual air supply quantity and the total quantity of the adjusted actual fuel carbon maintain a preset air-carbon ratio, and obtaining the optimal control parameters.
8. The method of claim 7, wherein optimizing the optimization control parameter based on the fuel property comprises: on-line evaluating real-time fuel characteristics through the three-dimensional temperature field, wherein the fuel characteristics comprise the firing rate, the burning rate and the burnout rate of the fuel; if the firing rate is lower than the firing rate threshold, on the basis of maintaining a preset wind-carbon ratio, improving the fuel distribution ratio of the burner close to the combustion area of the hearth, and synchronously adjusting the opening of the secondary air valve of the corresponding area; If the combustion rate is lower than the combustion rate threshold, adjusting the air supply rhythm of the secondary air to prolong the combustion time of the fuel in the hearth, and keeping the ratio of the actual air supply quantity to the adjusted actual fuel carbon total quantity to be in accordance with a preset air-carbon ratio; And if the burnout rate is lower than the burnout rate threshold value, increasing the opening degree of the burnout air door to supplement the burnout air supply.
9. The method of claim 1, further comprising an online update process for the optimized control parameters: Collecting real-time operation data after the unit implements the optimized control parameters, wherein the real-time operation data comprises actual radiant energy signals, actual combustion efficiency and actual pollutant emission data; comparing the actual combustion efficiency with the target combustion efficiency, the actual pollutant emission data with a preset emission limit value, and judging the suitability of the optimized control parameters; If the actual combustion efficiency is lower than the preset target combustion efficiency or the actual pollutant emission data exceeds the preset emission limit value, adjusting the association relation based on the real-time operation data; and updating the optimized control parameters of the fuel quantity and the air supply quantity according to the adjusted association relation.
10. An optimized control system of a coal-fired boiler based on a three-dimensional combustion radiant energy signal in the boiler, which is characterized by comprising: the acquisition module is used for acquiring radiation image information of combustion flame in the furnace through flame image detectors arranged around a hearth of the coal-fired boiler and reconstructing a three-dimensional temperature field in the furnace based on the radiation image information; the extraction module is used for extracting an internal combustion radiation energy signal of the furnace according to the three-dimensional temperature field and the radiation image information, and carrying out compensation treatment on the radiation energy signal so as to eliminate signal deviation caused by dust accumulation, coking and working condition fluctuation of the detector; The building module is used for building the association relation between the radiant energy signals and the unit operation parameters, wherein the unit operation parameters comprise unit load, fuel characteristics and air supply quantity; The determining module is used for determining the optimized control parameters of the fuel quantity and the air supply quantity based on the association relation and the deviation between the radiant energy signal and the unit load instruction, and optimizing the optimized control parameters based on the fuel property; and the adjusting module is used for adjusting the fuel supply quantity and the air supply quantity of the coal-fired boiler according to the optimized control parameters so as to enable the combustion heat release quantity in the boiler to be matched with the unit load demand.

Description

Coal-fired boiler optimal control method and system based on three-dimensional combustion radiant energy signals in furnace Technical Field The application relates to the technical field of combustion control of coal-fired boilers, in particular to an optimization control method and system of a coal-fired boiler based on a three-dimensional combustion radiant energy signal in the boiler. Background The coal-fired boiler is used as core equipment for power production, and under the background of improving the power generation duty ratio of new energy sources, the requirements of higher energy conservation, emission reduction and flexible load response are required to be met, and the existing coal-fired boiler combustion control is mostly dependent on indirect parameters such as steam side and the like, so that direct monitoring of the combustion state in the boiler is lacking, the control parameters are difficult to adapt to the fuel characteristic change, the matching degree of the combustion heat release amount in the boiler and the unit load requirement is insufficient, and the improvement of the combustion efficiency and the improvement of the operation stability are restricted. Disclosure of Invention In order to solve or at least partially solve the technical problems, the application provides an optimization control method and system for a coal-fired boiler based on a three-dimensional combustion radiant energy signal in the boiler. In a first aspect, the invention provides a coal-fired boiler optimization control method based on a three-dimensional combustion radiant energy signal in a furnace, comprising the following steps: s1, acquiring radiation image information of combustion flame in a coal-fired boiler through flame image detectors arranged around a hearth of the coal-fired boiler, and reconstructing a three-dimensional temperature field in the boiler based on the radiation image information; s2, extracting an internal combustion radiation energy signal of the furnace according to the three-dimensional temperature field and the radiation image information, and performing compensation treatment on the radiation energy signal to eliminate signal deviation caused by dust accumulation, coking and working condition fluctuation of the detector; S3, establishing an association relation between the radiant energy signal and unit operation parameters, wherein the unit operation parameters comprise unit load, fuel characteristics and air supply quantity; S4, determining optimal control parameters of fuel quantity and air supply quantity based on the association relation and deviation of the radiant energy signals and a unit load instruction, and optimizing the optimal control parameters based on fuel characteristics; and S5, adjusting the fuel supply quantity and the air supply quantity of the coal-fired boiler according to the optimized control parameters so as to enable the heat release quantity in the furnace to be matched with the load demand of the unit. Optionally, the reconstructing process of the three-dimensional temperature field includes: And excavating heat radiation transfer information contained in the radiation image information by adopting a DRESOR method, establishing the association between the heat radiation transfer information and the temperature of a combustion medium and the spatial distribution of a heat radiation source, and reconstructing the three-dimensional temperature field from the radiation image information by combining a corrected Tikhonov regularization method. Optionally, the process of extracting the radiant energy signal comprises: Calculating an initial radiant energy signal based on Stefin-Boltzmann's law in combination with temperature data of the three-dimensional temperature field, or calculating the initial radiant energy signal by gray values of the radiation image information; performing range conversion on the initial radiant energy signal by taking the actual power of the unit as a reference, and screening the radiant energy signal reflecting the actual load change of the unit; The process of compensating the radiant energy signal comprises: and aiming at the stage of severe change of the unit load, carrying out proportional correction based on the linear relation between the initial radiant energy signal and the unit power to finish the compensation processing of the radiant energy signal. Optionally, before performing range conversion on the initial radiant energy signal with the unit actual power as a reference, the method further includes: calculating a first deviation value between the initial radiant energy signals obtained based on the three-dimensional temperature field and the radiant image information, and judging whether the deviation value exceeds a deviation threshold value; If the first deviation value does not exceed the deviation threshold value, taking the average value of the two initial radiant energy signals as a final initial radiant e