A denitration control method and system for a deep peak-shaving coal-fired power generating unit

Abstract

The present disclosure relates to a denitration control method and system for a deep peak-shaving coal-fired power generating unit, the method is applied to a denitration system, the denitration system at least comprises a denitration tower, an ammonia injection device connected with the denitration tower, and an air preheater connected with the denitration tower, the method comprises: obtaining spectral data of a flue gas mixture of the denitration tower at a current time, the flue gas mixture at least comprises ammonia and nitrogen oxides; based on the spectral data, a first predicted concentration and a second predicted concentration are determined by using a preset regression model, the first predicted concentration represents a predicted concentration of ammonia escape at a next time, and the second predicted concentration represents a predicted concentration of nitrogen oxides at the next time; based on the first predicted concentration and the second predicted concentration, an ammonia injection amount of the ammonia injection device and / or an air volume of the air preheater are controlled. The present disclosure realizes accurate monitoring and control of the denitration process under low load conditions, does not need to rely on manual adjustment, reduces the probability of ammonia escape, and improves the denitration efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of power control technology, and more specifically, to a denitrification control method and system for deep peak-shaving coal-fired power generating units. Background Technology

[0002] In recent years, with the continuous growth of installed capacity of new energy sources, coal-fired power units undertaking peak shaving tasks for the power grid has become a future development trend. However, after undertaking peak shaving tasks, coal-fired power units will operate under low-load conditions for extended periods, which will pose various safety risks to the safe and stable operation of the units. For example, frequent operation of coal-fired power units under low-load conditions will cause parameters such as particulate matter, sulfur oxides, and nitrogen oxides in the flue gas to deviate significantly from the design values ​​of the denitrification system, putting coal-fired power plants under the dual pressure of deep peak shaving and ultra-low emissions.

[0003] Currently, to maintain compliance with nitrogen oxide emission standards in flue gas, denitrification systems often employ a conservative strategy of excessive ammonia injection to reduce nitrogen oxides, resulting in a significant increase in ammonia slip. This escaped ammonia combines with sulfur trioxide in the flue gas to form ammonium bisulfate in subsequent process stages, causing a series of problems such as air preheater blockage and corrosion, increased system resistance, and escalating operating costs. Furthermore, existing denitrification solutions are generally inadequate to meet operational demands, lack real-time and accurate monitoring methods for ammonia slip, rely heavily on personnel experience for operational adjustments, and lack effective feedback control mechanisms.

[0004] Therefore, the inability of current denitrification solutions to meet the demands of low-load operation and maintain denitrification efficiency is a pressing technical problem that needs to be solved. Summary of the Invention

[0005] The purpose of this disclosure is to provide a denitrification control method and system for deep peak-shaving coal-fired power generating units, which can accurately monitor and control the denitrification process of nitrogen oxides in ammonia injection reduction flue gas under low-load operating conditions, without relying on manual adjustment, reducing the probability of ammonia escape and improving denitrification efficiency.

[0006] To achieve the above objectives, a first aspect of this disclosure provides a denitrification control method for a deep peak-shaving coal-fired power generating unit, applied to a denitrification system. The denitrification system includes at least a denitrification tower, an ammonia injection device connected to the denitrification tower, and an air preheater connected to the denitrification tower. The method includes: Obtain spectral data of the flue gas mixture at the current moment of the denitrification tower, wherein the flue gas mixture includes at least ammonia and nitrogen oxides; Based on the spectral data, a first predicted concentration and a second predicted concentration are determined using a preset regression model. The first predicted concentration represents the predicted concentration of ammonia escape at the next moment, and the second predicted concentration represents the predicted concentration of nitrogen oxides at the next moment. Based on the first predicted concentration and the second predicted concentration, the ammonia injection rate of the ammonia injection equipment and / or the air volume of the air preheater are controlled.

[0007] Optionally, the spectral data includes first spectral data and second spectral data; The first spectral data includes at least one of the following: ammonia molecule spectral line intensity, amino radical spectral line intensity, imino radical spectral line intensity, and hydrogen atom spectral line intensity; The second spectral data includes at least one of the following: nitrogen atom spectral line intensity, oxygen atom spectral line intensity, and nitric oxide molecule spectral line intensity; The step of determining the first predicted concentration and the second predicted concentration based on the spectral data using a preset regression model includes: Based on the first spectral data, the first predicted concentration is determined using the preset regression model; The second predicted concentration is determined using the preset regression model based on the second spectral data.

[0008] Optionally, controlling the ammonia injection rate of the ammonia injection device and / or the airflow rate of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection equipment is controlled to adjust the ammonia injection rate according to a preset ammonia reduction strategy; the preset ammonia reduction strategy means that as the first predicted concentration increases, the ammonia injection rate of the ammonia injection equipment decreases at a first preset rate gradient.

[0009] Optionally, controlling the ammonia injection rate of the ammonia injection device and / or the airflow rate of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being less than or equal to the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the air preheater is controlled to operate at a first preset airflow rate, and the ammonia injection rate of the ammonia injection device is controlled to increase at a second preset rate gradient.

[0010] Optionally, controlling the ammonia injection rate of the ammonia injection device and / or the airflow rate of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection equipment is controlled to be reduced to the first ammonia injection rate threshold, and after a first preset duration, the air preheater is controlled to operate at the second preset airflow rate.

[0011] Optionally, the method further includes: If, within a second preset time period after the air preheater starts operating at the second preset air volume, the first predicted concentration decreases and the second predicted concentration increases, the ammonia injection quantity of the ammonia injection equipment is controlled to decrease to a second ammonia injection quantity threshold, where the second ammonia injection quantity threshold is less than the first ammonia injection quantity threshold. If, within a second preset time period after the air preheater starts operating at the second preset airflow, the rate of decrease of the first predicted concentration is greater than a preset speed threshold and the second predicted concentration increases, the ammonia injection equipment is controlled to stop working, and the air preheater is controlled to operate at a third preset airflow, which is greater than the second preset airflow.

[0012] Optionally, controlling the ammonia injection rate of the ammonia injection device and / or the airflow rate of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being less than or equal to the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection equipment and the air volume of the air preheater are both kept unchanged.

[0013] A second aspect of this disclosure provides a denitrification system for a coal-fired power generating unit, the denitrification system comprising at least: A denitrification tower, an ammonia injection device connected to the denitrification tower, and an air preheater connected to the denitrification tower; A spectrometer is used to collect spectral data of the flue gas mixture in the denitrification tower, the flue gas mixture comprising at least ammonia and nitrogen oxides; A controller for performing the steps of the method as described in any of the first aspects.

[0014] A third aspect of this disclosure provides a non-transitory computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the steps of the method described in any of the first aspects.

[0015] A fourth aspect of this disclosure provides an electronic device comprising: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the steps of the method of any one of the first aspects.

[0016] The above technical solution, based on the spectral data of the flue gas mixture (including ammonia and nitrogen oxides) at the current moment in the denitrification tower, uses a preset regression model to determine a first predicted concentration and a second predicted concentration. The first predicted concentration represents the predicted concentration of ammonia escape at the next moment, and the second predicted concentration represents the predicted concentration of nitrogen oxides at the next moment. Then, based on the first and second predicted concentrations, the ammonia injection rate of the ammonia injection equipment and / or the airflow of the air preheater are controlled. This achieves precise monitoring and control of the denitrification process of reducing nitrogen oxides in the flue gas with ammonia injection under low-load operating conditions, without relying on manual adjustments, reducing the probability of ammonia escape, improving denitrification efficiency, and enhancing the system safety and reliability of the coal-fired power generating unit.

[0017] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is an application scenario diagram of a denitrification control method for a coal-fired power generation unit, as illustrated in this public example.

[0019] Figure 2 This is a first flowchart of a denitrification control method for a coal-fired power generating unit, as exemplified in this disclosure.

[0020] Figure 3 This is a second flowchart of a denitrification control method for a coal-fired power generation unit, as exemplified in this disclosure.

[0021] Figure 4 This is a third flowchart of a denitrification control method for a coal-fired power generating unit, as exemplified in this disclosure.

[0022] Figure 5 This is the fourth flowchart of a denitrification control method for a coal-fired power generating unit, as exemplified in this disclosure.

[0023] Figure 6 This is the fifth flowchart of a denitrification control method for a coal-fired power generation unit, as exemplified in this disclosure.

[0024] Figure 7 This is the sixth flowchart of a denitrification control method for a coal-fired power generation unit, as illustrated in this disclosure.

[0025] Figure 8 This is a structural block diagram of a denitrification system for a coal-fired power generation unit, as exemplified in this disclosure.

[0026] Figure 9 This is a system block diagram of an electronic device as an example of this disclosure. Detailed Implementation

[0027] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0028] It should be noted that all actions involving the acquisition of signals, information, or data in this disclosure are carried out in compliance with the relevant data protection laws and policies of the country where the location is situated, and with authorization from the owner of the relevant device.

[0029] Existing denitrification solutions typically rely on open-loop control with fixed parameters, focusing on high-temperature denitrification within the furnace and adjusting ammonia injection based on hysteresis feedback, or optimizing the local flow field solely through mechanical unclogging. However, these solutions often lack the crucial element of in-situ, precise monitoring of escaped ammonia and its derivatives, as well as residual NO, downstream of the denitrification system. This prevents them from dynamically coordinating the optimal ratio between ammonia injection and air preheater ventilation, making it difficult to simultaneously address the industry pain points of ammonia escape, NO exceeding standards, and air preheater blockage under complex operating conditions such as low loads.

[0030] Based on this, the present disclosure provides a denitrification control method for a deep peak-shaving coal-fired power generation unit. The denitrification control method is applied to a denitrification system, which includes at least a denitrification tower, an ammonia injection device connected to the denitrification tower, and an air preheater connected to the denitrification tower.

[0031] refer to Figure 1 This is a schematic diagram illustrating an application scenario of the denitrification control method in this embodiment. In this application scenario, the coal-fired power generation unit includes a coal-fired boiler 10, a superheater 20, a high-pressure cylinder 30, a low-pressure cylinder 40, and a generator 50 connected in sequence, as well as a denitrification system 60, a dust collector 70, a desulfurization tower 80, and a chimney 90 connected in sequence to the superheater 20. The denitrification system 60 includes a denitrification tower 61, an ammonia injection device 62 connected to the denitrification tower 61, an air preheater 63 connected to the denitrification tower 61, a spectrometer 64 connected to the denitrification tower 61, and a controller 65. The controller 65 is electrically connected to the ammonia injection device 62, the air preheater 63, and the spectrometer 64, respectively, and is used to execute the denitrification control method of this embodiment. The denitrification system 60 is used to remove nitrogen oxides, such as nitric oxide (NO) and nitrogen dioxide (NO2), from the flue gas from the combustion boiler 10. The ammonia injection device 62 is used to input ammonia (NH3) into the denitrification tower 61. Inside the denitrification tower 61, NH3 undergoes a reduction reaction with NO and NO2 to produce nitrogen (N2) and water (H2O). During this process, the air preheater 64 uses the tail end of the coal-fired boiler 10 to heat the temperature of the flue gas entering the denitrification tower 61, thereby enhancing the denitrification efficiency.

[0032] refer to Figure 2 The denitrification control method specifically includes the following steps: Step S201: Obtain the spectral data of the flue gas mixture at the current moment of the denitrification tower 61. The flue gas mixture includes at least ammonia and nitrogen oxides.

[0033] Denitrification tower 61 is a reaction vessel used for the denitrification reduction reaction of flue gas and ammonia. Denitrification tower 61 can also be equipped with a plasma-coupled catalyst device to enhance the catalytic denitrification reaction.

[0034] The flue gas mixture is the flue gas and ammonia gas inside the denitrification tower 61. For example, a spectrometer 64 is installed in the bypass flue after the denitrification tower 61 to collect spectral data of the flue gas mixture.

[0035] Spectral data is used to reflect the numerical sequence of light intensity absorbed, emitted, or scattered by a flue gas mixture under electromagnetic radiation at different wavelengths or frequencies. For example, a set of spectral data showing the change in light intensity as a function of wavenumber obtained by Fourier transforming an interferogram is provided. The horizontal axis of the spectrum represents the wavenumber, and the vertical axis represents the absorbance or transmittance. Ammonia, nitric oxide, nitrogen dioxide, etc., all have characteristic absorption peaks in the mid-infrared region.

[0036] Step S202: Based on spectral data, use a preset regression model to determine the first predicted concentration and the second predicted concentration. The first predicted concentration represents the predicted concentration of ammonia escape at the next moment, and the second predicted concentration represents the predicted concentration of nitrogen oxides at the next moment.

[0037] A pre-trained regression model is a regression model that utilizes spectral data under various operating conditions to establish the relationship between the input spectral data and the output predicted concentration. Pre-trained regression models can be, but are not limited to, linear regression models, multinomial regression models, multiple linear regression models, etc.

[0038] Step S203: Based on the first predicted concentration and the second predicted concentration, control the ammonia injection rate of the ammonia injection device 62 and / or the air volume of the air preheater 63.

[0039] Based on the levels of the first and second predicted concentrations, the operating conditions of the denitrification reaction at the next moment can be predicted, such as excessive ammonia injection, insufficient ammonia injection, and the reaction ratios of ammonia and nitrogen oxides both meeting or exceeding the standards.

[0040] For example, if the denitrification reaction condition is predicted to be excessive ammonia injection at the next moment, the ammonia injection rate of the ammonia injection device 62 at the next moment is adjusted to decrease.

[0041] For example, if the denitrification reaction condition is predicted to be insufficient ammonia injection in the next moment, the ammonia injection amount of the ammonia injection device 62 in the next moment can be increased, and the air volume of the air preheater 63 can also be increased to enhance the denitrification reaction.

[0042] For example, if it is predicted that the denitrification reaction condition at the next moment will be that both ammonia and nitrogen oxides meet the standards, the ammonia injection quantity of the ammonia injection device 62 and the air volume of the air preheater 63 at the next moment will remain unchanged.

[0043] For example, if the denitrification reaction is predicted to occur in the next moment when both ammonia and nitrogen oxides exceed the standard, this situation is highly prone to ammonia escape. This causes the excess ammonia to react with sulfur trioxide in the flue gas to form ammonium bisulfate, leading to problems such as blockage and corrosion of the air preheater 63. Therefore, in this case, the ammonia injection rate of the ammonia injection device 62 is reduced in the next moment, while the airflow of the air preheater 63 is increased to adjust the reaction ratio and enhance the denitrification reaction.

[0044] In this embodiment, the spectral data of the flue gas mixture (including ammonia and nitrogen oxides) at the current moment in the denitrification tower 61 are used to predict the first predicted concentration of ammonia escape and the second predicted concentration of nitrogen oxides at the next moment using a preset regression model. Based on these first and second predicted concentrations, the ammonia injection rate of the ammonia injection device 62 and / or the airflow of the air preheater 63 are controlled. This achieves precise monitoring and control of the denitrification process for reducing nitrogen oxides in the flue gas by ammonia injection under low-load operating conditions, without relying on manual adjustments, reducing the probability of ammonia escape and improving denitrification efficiency.

[0045] As an optional implementation, the spectral data in this disclosure includes first spectral data and second spectral data.

[0046] The first spectral data includes at least one of the following: the intensity of the ammonia molecule spectral line, the intensity of the amino radical spectral line, the intensity of the imino radical spectral line, and the intensity of the hydrogen atom spectral line.

[0047] The second spectral data includes at least one of the following: nitrogen atom spectral line intensity, oxygen atom spectral line intensity, and nitric oxide molecule spectral line intensity.

[0048] Based on spectral data and using a pre-defined regression model, the first and second predicted concentrations are determined, including: Based on the first spectral data, the first predicted concentration is determined using a pre-defined regression model; The second predicted concentration is determined using a pre-defined regression model based on the second spectral data.

[0049] Among them, the intensity of the ammonia molecule spectral line represents the intensity of the characteristic absorption and emission peak of the ammonia molecule; the intensity of the amino radical spectral line represents the intensity of the characteristic peak of the amino radical; the intensity of the imino radical spectral line represents the intensity of the characteristic peak of the imino radical; the intensity of the hydrogen atom spectral line represents the intensity of the specific atomic spectral line of the hydrogen atom; the intensity of the nitrogen atom spectral line represents the intensity of the specific atomic spectral line of the nitrogen atom; the intensity of the oxygen atom spectral line represents the intensity of the specific atomic spectral line of the oxygen atom; and the intensity of the nitric oxide molecule spectral line represents the intensity of the characteristic absorption and emission peak of the nitric oxide molecule.

[0050] For example, for each spectral data i at a specific wavelength or band, the intensities of multiple characteristic absorption / emission peaks of the ammonia molecule (NH3) are represented as { , ,..., }, The intensity of the characteristic absorption / emission peak of the i-th ammonia molecule is represented by {}; the intensities of multiple characteristic peaks of the amino radical (NH2) are represented by { , ,..., }, The intensity of the characteristic peak of the i-th amino radical is represented by {}; the intensities of multiple characteristic peaks of the imine radical (NH) are represented by { ,..., }, The intensity of the characteristic peak of the i-th imino radical is represented by {}; the intensity of a specific atomic spectral line of nitrogen (N) is represented by { , ,..., }, The intensity of a specific atomic spectral line of the i-th nitrogen atom is represented as { ,..., }, The intensity of the characteristic absorption / emission peak of the i-th hydrogen atom is represented by {}; the intensities of multiple characteristic absorption / emission peaks of the nitric oxide (NO) molecule are represented by { , ,…, }, This represents the intensity of the characteristic absorption / emission peak of the i-th nitric oxide molecule. Therefore, the expression for the preset regression model in this embodiment can be expressed as: ; ; In the formula, C1 is the first predicted concentration; C2 is the second predicted concentration; b1 is the first fitting constant; and b2 is the second fitting constant. for The corresponding weighting coefficient, where n represents the number of ammonia molecules in the spectral data; for The corresponding weighting coefficient, m, indicates that the spectral data contains m amino radicals; for The corresponding weighting coefficient, k, indicates that the spectral data contains k imino radicals; for The corresponding weighting coefficients, Related to the nitrogen atoms in the ammonia molecule, t indicates that the ammonia molecule in the spectral data contains t nitrogen atoms; for The corresponding weighting coefficient, h, indicates that the spectral data includes h hydrogen atoms; , , , The sum of is 1. for The corresponding weighting coefficient, q, indicates that the spectral data contains q nitric oxide molecules; for The corresponding weighting coefficients, Related to the nitrogen atoms in the nitric oxide molecule, p indicates that the nitric oxide molecule in the spectral data contains p nitrogen atoms; for The corresponding weighting coefficient, f, indicates that the spectral data contains f oxygen atoms; , , The sum of is 1.

[0051] For example, a preset regression model is trained using historical spectral data from multiple sets of coal-fired power generation units under different loads, different coal quality conditions, and different catalyst activity states. After multiple error corrections, the optimal first and second fitting constants are obtained.

[0052] Historical spectral data includes historical true values ​​for escaped ammonia concentrations and historical true values ​​for nitrogen oxide concentrations. Furthermore, the aforementioned weighting coefficients... , , , , , , , It can be determined using the following error evaluation function: ； ; In the formula, L1 is the first total error and L2 is the second total error; For the true value of historical escape ammonia concentration, This represents the true historical concentration of nitrogen oxides. for The corresponding weighting coefficient, where n represents the number of ammonia molecules in the spectral data; for The corresponding weighting coefficient, m, indicates that the spectral data contains m amino radicals; for The corresponding weighting coefficient, k, indicates that the spectral data contains k imino radicals; for The corresponding weighting coefficients, Related to the nitrogen atoms in the ammonia molecule, t indicates that the ammonia molecule in the spectral data contains t nitrogen atoms; for The corresponding weighting coefficient, h, indicates that the spectral data includes h hydrogen atoms; , , , The sum of is 1. for The corresponding weighting coefficient, q, indicates that the spectral data contains q nitric oxide molecules; for The corresponding weighting coefficients, Related to the nitrogen atoms in the nitric oxide molecule, p indicates that the nitric oxide molecule in the spectral data contains p nitrogen atoms; for The corresponding weighting coefficient, f, indicates that the spectral data contains f oxygen atoms; , , The sum of these values ​​is 1. During the iteration process, using the aforementioned error evaluation function, the values ​​of each weight coefficient are gradually adjusted using a gradient descent algorithm, with the goal of minimizing the first total error (the sum of the deviations between the first predicted concentration and the true value of the escaped ammonia concentration) and the second total error (the sum of the deviations between the second predicted concentration and the true value of the nitrogen oxide concentration). After multiple rounds of iterative iteration, the optimal combination of weight coefficients that balances robustness and prediction accuracy is finally obtained, improving the prediction reliability and adaptability of the preset regression model.

[0053] In this embodiment, by using a preset regression model, the characteristic peaks of ammonia and nitric oxide molecules in the spectral data are analyzed. By extracting the intensity of the characteristic peaks, a quantitative correlation between spectral features and gas concentration is established, thereby quickly outputting the first and second predicted concentrations of the denitrification tower 61, further improving the prediction accuracy and denitrification efficiency.

[0054] As an optional implementation method, refer to Figure 3 According to the embodiments of this disclosure, the ammonia injection rate of the ammonia injection device 62 and / or the air volume of the air preheater 63 are controlled based on a first predicted concentration and a second predicted concentration, including: Step S301: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection device 62 is controlled to adjust the ammonia injection amount according to a preset ammonia reduction strategy; the preset ammonia reduction strategy means that as the first predicted concentration increases, the ammonia injection amount of the ammonia injection device 62 decreases at a first preset rate gradient.

[0055] Specifically, if the first predicted concentration is greater than the escape ammonia concentration threshold and the second predicted concentration is less than or equal to the nitrogen oxide concentration threshold, it indicates that the ammonia injection in the denitrification tower 61 is excessive. At this time, the denitrification efficiency meets the emission requirements, but excessive ammonia injection leads to ammonia escape exceeding the limit. If this continues for a long time, it can easily cause problems such as blockage and corrosion of the air preheater 63. Therefore, the ammonia injection equipment 62 is controlled to adjust the ammonia injection rate according to the preset ammonia reduction strategy.

[0056] The preset ammonia reduction strategy means that as the first predicted concentration increases, the ammonia injection rate of the ammonia injection device 62 decreases according to a first preset rate gradient. The first preset rate gradient can be set in multiple stages according to the extent to which the first predicted concentration exceeds the escape ammonia concentration threshold.

[0057] For example, if the first predicted concentration exceeds the escaped ammonia concentration threshold by less than or equal to 2 ppm, the ammonia injection rate of the ammonia injection device 62 is gradually reduced at a rate of 1% to 2% every 30 seconds; if the first predicted concentration exceeds the escaped ammonia concentration threshold by more than 2 ppm, the ammonia injection rate is first rapidly reduced at a rate of 2% every 20 seconds to approximately the ammonia injection rate threshold, and then switched to a slow adjustment mode, such as gradually reducing the ammonia injection rate of the ammonia injection device 62 at a rate of 1% to 2% every 30 seconds.

[0058] For example, during the process of controlling the ammonia injection device 62 to adjust the ammonia injection amount according to the preset ammonia reduction strategy, the spectral data of the flue gas mixture in the denitrification tower 61 is monitored in real time. When the first predicted concentration is reduced to 90% of the escape ammonia concentration threshold, the ammonia injection amount is stopped to avoid the problem of subsequent nitrogen oxide concentration rebound due to excessive ammonia reduction. This way, ammonia escape can be controlled quickly, and denitrification efficiency can be improved.

[0059] In this embodiment, when the first predicted concentration is greater than the escape ammonia concentration threshold and the second predicted concentration is less than or equal to the nitrogen oxide concentration threshold, the ammonia injection device 62 is controlled to adjust the ammonia injection rate according to a preset ammonia reduction strategy. Furthermore, the ammonia injection rate of the ammonia injection device 62 is set to decrease at a first preset rate gradient as the first predicted concentration increases, achieving precise and efficient control of the ammonia injection rate. This avoids ammonia waste caused by excessive ammonia injection, ammonia escape due to insufficient ammonia reduction, and a subsequent rebound in nitrogen oxide concentration due to excessive ammonia reduction, significantly improving denitrification efficiency.

[0060] As an optional implementation method, refer to Figure 4According to the embodiments of this disclosure, the ammonia injection rate of the ammonia injection device 62 and / or the air volume of the air preheater 63 are controlled based on a first predicted concentration and a second predicted concentration, including: Step S401: In response to the first predicted concentration being less than or equal to the escape ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the air preheater 63 is controlled to operate at the first preset air volume, and the ammonia injection quantity of the ammonia injection device 62 is controlled to increase at the second preset rate gradient.

[0061] Specifically, if the first predicted concentration is less than or equal to the escape ammonia concentration threshold, and the second predicted concentration is greater than the nitrogen oxide concentration threshold, it indicates that the ammonia injection rate in the denitrification tower 61 is insufficient. At this point, ammonia escape is within a safe range, but nitrogen oxide emissions do not meet standards. Therefore, while ensuring that ammonia escape does not exceed limits, the ammonia injection rate needs to be increased or the denitrification reaction conditions optimized to ensure that nitrogen oxide emissions meet ultra-low emission standards. Thus, the air preheater 63 is preferentially controlled to operate at the first preset airflow rate, while the ammonia injection rate of the ammonia injection device 62 is controlled to increase at a second preset rate gradient.

[0062] For example, by opening the bypass valve at the outlet of the air preheater 63, some high-temperature flue gas is introduced, raising the inlet flue gas temperature in the denitrification tower 61 by 5-10°C, widening the catalyst activity temperature window, and enhancing the denitrification reaction efficiency. Simultaneously, the ammonia injection rate of the ammonia injection device 62 can be increased in a gradient of 1.5% to 3% every 15 seconds, with a focus on areas with higher predicted concentrations. If the second predicted concentration does not decrease after 3 minutes of opening the bypass valve of the air preheater 63, the opening of the bypass valve of the air preheater 63 is further increased to the maximum allowable value, increasing the airflow of the air preheater 63 and activating the plasma-coupled catalyst device. This auxiliary energy input enhances catalyst activity, ensuring that the nitrogen oxide concentration is quickly reduced to within emission standards while maintaining ammonia escape limits.

[0063] In this embodiment, when the first predicted concentration is less than or equal to the escaped ammonia concentration threshold and the second predicted concentration is greater than the nitrogen oxide concentration threshold, the air preheater 63 is controlled to operate at a first preset airflow rate, and the ammonia injection rate of the ammonia injection device 62 is controlled to increase at a second preset rate gradient. This avoids the problem of nitrogen oxide emissions not meeting standards due to insufficient ammonia injection in the denitrification tower 61, and further improves the denitrification reaction efficiency while balancing ammonia escape within limits and nitrogen oxide emissions meeting ultra-low standards.

[0064] As an optional implementation method, refer to Figure 5 According to the embodiments of this disclosure, the ammonia injection rate of the ammonia injection device 62 and / or the air volume of the air preheater 63 are controlled based on a first predicted concentration and a second predicted concentration, including: Step S501: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection device 62 is controlled to be reduced to the first ammonia injection rate threshold, and after a first preset duration, the air preheater 63 is controlled to operate at the second preset air volume.

[0065] Specifically, if the first predicted concentration is greater than the escaped ammonia concentration threshold and the second predicted concentration is greater than the nitrogen oxide concentration threshold, it indicates an abnormal operating condition in the denitrification tower 61 where both escaped ammonia concentration and nitrogen oxide concentration exceed the standard. This is usually due to problems such as catalyst activity decay, drastic fluctuations in flue gas parameters, or turbulent flow field. Therefore, the ammonia injection rate of the ammonia injection device 62 is reduced to the first ammonia injection rate threshold, and after a first preset duration, the air preheater 63 is controlled to operate at the second preset airflow rate.

[0066] For example, by reducing the total opening degree of the ammonia injection device 62 to a preset safe opening degree, the ammonia injection rate is reduced to a first ammonia injection rate threshold, such as 60% to 70% of the normal operating condition, thereby quickly curbing the worsening trend of ammonia escape. After maintaining the first ammonia injection rate threshold for a first preset time, such as 1 to 2 minutes, the air preheater 63 outlet bypass valve is opened to control the output of the air preheater 63 to a second preset air volume, so that high-temperature flue gas is introduced into the denitrification tower 61 to optimize the denitrification reaction temperature.

[0067] In this embodiment, when a predicted concentration is greater than the escape ammonia concentration threshold and a second predicted concentration is greater than the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection device 62 is reduced to a first ammonia injection rate threshold, and after a first preset duration, the air preheater 63 is controlled to operate at a second preset airflow rate. Thus, by dually regulating the reaction ratio and reaction temperature of ammonia and nitrogen oxides within the denitrification tower 61, bidirectional convergence of ammonia escape and nitrogen oxide concentration is achieved, optimizing the control of the denitrification reaction process and improving denitrification efficiency.

[0068] As an optional implementation method, refer to Figure 6 The denitrification control method of this disclosure embodiment further includes: Step S601: During the second preset time period after the air preheater 63 starts operating at the second preset air volume, if the first predicted concentration decreases and the second predicted concentration increases, the ammonia injection quantity of the ammonia injection device 62 is controlled to decrease to the second ammonia injection quantity threshold, which is less than the first ammonia injection quantity threshold. Step S602: Within the second preset time period after the air preheater 63 starts operating at the second preset air volume, if the rate of decrease of the first predicted concentration is greater than the preset rate threshold and the second predicted concentration increases, control the ammonia injection equipment 62 to stop working and control the air preheater 63 to operate at the third preset air volume, which is greater than the second preset air volume.

[0069] For example, during a second preset time period, such as 2-3 minutes, after the air preheater 63 starts operating at the second preset airflow rate, the spectral data of the flue gas mixture in the denitrification tower 61 is continuously monitored. If the first predicted concentration decreases but the second predicted concentration increases simultaneously, it indicates that the current ammonia injection rate is still too high. Therefore, the ammonia injection rate of the ammonia injection device 62 is further reduced to the second ammonia injection rate threshold, for example, by further reducing the ammonia injection rate at a rate of 1% every 20 seconds.

[0070] For example, a decrease in the first predicted concentration means that the first predicted concentration decreases continuously over a second preset time period. For instance, the first predicted concentration decreases linearly from 4.6 ppmv to 2 ppm within 10 seconds.

[0071] For example, the decrease in the first predicted concentration may also refer to situations such as: within a second preset time period, the first predicted concentration first decreases and then remains unchanged, the first predicted concentration first remains unchanged and then decreases, the first predicted concentration decreases at a certain moment and does not increase, or the first predicted concentration gradient decreases.

[0072] For example, during a second preset time period after the air preheater 63 starts operating at the second preset airflow rate, the rate of decrease of the first predicted concentration is monitored in real time. If the rate of decrease exceeds a preset speed threshold and the second predicted concentration increases, it indicates that the ammonia injection amount is sufficient, but the nitrogen oxide concentration may exceed the standard. Therefore, the ammonia injection device 62 is controlled to stop working, and the operating airflow rate of the air preheater 63 is controlled to increase from the second preset airflow rate to the third preset airflow rate, thereby increasing the reaction temperature and promoting the degradation of nitrogen oxides.

[0073] In this embodiment, by monitoring spectral data in real time during the second preset time period after the air preheater 63 starts operating at the second preset air volume, and by finely controlling the reaction ratio and reaction temperature of ammonia and nitrogen oxides in the denitrification tower 61 according to the real-time trends of the first and second predicted concentrations, the bidirectional convergence of ammonia escape and nitrogen oxide concentration is further optimized, thereby improving the denitrification efficiency.

[0074] As an optional implementation method, refer to Figure 7 According to the embodiments of this disclosure, the ammonia injection rate of the ammonia injection device 62 and / or the air volume of the air preheater 63 are controlled based on a first predicted concentration and a second predicted concentration, including: Step S701: In response to the first predicted concentration being less than or equal to the escape ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection device 62 and the air volume of the air preheater 63 are both kept unchanged.

[0075] Specifically, if the first predicted concentration is less than or equal to the escape ammonia concentration threshold, and the second predicted concentration is less than or equal to the nitrogen oxide concentration threshold, it indicates that the operating conditions inside the denitrification tower 61 are normal, suggesting that the denitrification system 60 is operating stably and that the reaction ratio and reaction temperature between the ammonia injection rate and nitrogen oxides are well matched. Therefore, the ammonia injection rate of the ammonia injection device 62 and the air volume of the air preheater 63 are kept constant. Simultaneously, a steady-state PID (Proportional-Integral-Derivative) control algorithm can be used to suppress small load fluctuations; for example, only minor adjustments can be made to small disturbances with load fluctuations less than or equal to 5% / min.

[0076] In this embodiment, by monitoring the first and second predicted concentrations in real time, ammonia slip and nitrogen oxide concentrations are always kept at the lowest level while meeting emission standards. This not only balances environmental protection and denitrification costs, but also improves the system safety and reliability of coal-fired power generating units.

[0077] Based on the same inventive concept, this disclosure also provides a denitrification system for a coal-fired power generation unit. Referring to the figures, the denitrification system includes at least: Denitrification tower 801, ammonia injection equipment 802 connected to the denitrification tower, and air preheater 803 connected to the denitrification tower; Spectrometer 804 is used to collect spectral data of the flue gas mixture in denitrification tower 801, which includes at least ammonia and nitrogen oxides; The controller 805 is used to perform the steps of the denitrification control method as described in any of the above embodiments.

[0078] As an optional real-time method, the spectral data includes first spectral data and second spectral data; The first spectral data includes at least one of the following: the intensity of the ammonia molecule spectral line, the intensity of the amino radical spectral line, the intensity of the imino radical spectral line, and the intensity of the hydrogen atom spectral line; The second spectral data includes at least one of the following: nitrogen atom spectral line intensity, oxygen atom spectral line intensity, and nitric oxide molecule spectral line intensity; Controller 805 is used to determine a first predicted concentration and a second predicted concentration based on spectral data and using a preset regression model, including: Based on the first spectral data, the first predicted concentration is determined using a pre-defined regression model; The second predicted concentration is determined using a pre-defined regression model based on the second spectral data.

[0079] As an optional real-time method, controller 805 is used to control the ammonia injection rate of ammonia injection equipment 802 and / or the airflow of air preheater 803 based on a first predicted concentration and a second predicted concentration, including: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection device 802 is controlled to adjust the ammonia injection amount according to a preset ammonia reduction strategy; the preset ammonia reduction strategy means that as the first predicted concentration increases, the ammonia injection amount of the ammonia injection device 802 decreases at a first preset rate gradient.

[0080] As an optional real-time method, controller 805 is used to control the ammonia injection rate of ammonia injection equipment 802 and / or the airflow of air preheater 803 based on a first predicted concentration and a second predicted concentration, including: In response to the first predicted concentration being less than or equal to the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the air preheater 803 is controlled to operate at the first preset air volume, and the ammonia injection quantity of the ammonia injection device 802 is controlled to increase at the second preset rate gradient.

[0081] As an optional real-time method, controller 805 is used to control the ammonia injection rate of ammonia injection equipment 802 and / or the airflow of air preheater 803 based on a first predicted concentration and a second predicted concentration, including: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection device 802 is reduced to the first ammonia injection rate threshold, and after a first preset duration, the air preheater 803 is controlled to operate at the second preset air volume.

[0082] As an optional real-time mode, controller 805 is also used for: If the first predicted concentration decreases and the second predicted concentration increases within a second preset time period after the air preheater 803 starts operating at the second preset air volume, the ammonia injection quantity of the ammonia injection device 802 is reduced to the second ammonia injection quantity threshold, and the second ammonia injection quantity threshold is less than the first ammonia injection quantity threshold. If, within a second preset time period after the air preheater 803 starts operating at the second preset air volume, the rate of decrease of the first predicted concentration is greater than the preset rate threshold and the second predicted concentration increases, the ammonia injection device 802 is controlled to stop working, and the air preheater 803 is controlled to operate at the third preset air volume, which is greater than the second preset air volume.

[0083] As an optional real-time method, controller 805 is used to control the ammonia injection rate of ammonia injection equipment 802 and / or the airflow of air preheater 803 based on a first predicted concentration and a second predicted concentration, including: In response to the first predicted concentration being less than or equal to the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection device 802 and the air volume of the air preheater 803 are kept unchanged.

[0084] Regarding the system in the above embodiments, the specific ways in which each module performs operations have been described in detail in the embodiments related to the method, and will not be elaborated here.

[0085] This disclosure also provides an electronic device, including: A memory on which computer programs are stored; A processor is configured to execute a computer program in the memory to implement the steps of the denitrification control method in any of the above embodiments.

[0086] Figure 9 This is a block diagram illustrating an electronic device 900 according to an exemplary embodiment. For example... Figure 9 As shown, the electronic device 900 may include a processor 901 and a memory 902. The electronic device 900 may also include one or more of a multimedia component 903, an input / output (I / O) interface 904, and a communication component 905.

[0087] The processor 901 controls the overall operation of the electronic device 900 to complete all or part of the steps in the aforementioned denitrification control method. The memory 902 stores various types of data to support the operation of the electronic device 900. This data may include, for example, instructions for any application or method operating on the electronic device 900, and application-related data such as contact data, sent and received messages, pictures, audio, video, etc. The memory 902 can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read-Only Memory (EPROM), Programmable Read-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The multimedia component 903 may include a screen and audio components. The screen may be, for example, a touchscreen, and the audio component is used to output and / or input audio signals. For example, the audio component may include a microphone for receiving external audio signals. The received audio signals may be further stored in memory 902 or transmitted via communication component 905. The audio component also includes at least one speaker for outputting audio signals. I / O interface 904 provides an interface between processor 901 and other interface modules, such as a keyboard, mouse, buttons, etc. These buttons may be virtual or physical buttons. Communication component 905 is used for wired or wireless communication between the electronic device 900 and other devices. Wireless communication, such as Wi-Fi, Bluetooth, Near Field Communication (NFC), 2G, 3G, 4G, NB-IoT, eMTC, or other 5G technologies, or combinations thereof, is not limited here. Therefore, the corresponding communication component 905 may include: a Wi-Fi module, a Bluetooth module, an NFC module, etc.

[0088] In an exemplary embodiment, the electronic device 900 may be implemented by one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), controllers, microcontrollers, microprocessors, or other electronic components to perform the denitrification control method described above.

[0089] In another exemplary embodiment, a non-transitory computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the denitrification control method described above. For example, the computer-readable storage medium may be the memory 902 described above that includes the computer program, which may be executed by the processor 901 of the electronic device 900 to complete the denitrification control method described above.

[0090] In another exemplary embodiment, a computer program product is also provided, the computer program product comprising a computer program executable by a programmable device, the computer program having a code portion for performing the above-described denitrification control method when executed by the programmable device.

[0091] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0092] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0093] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A denitrification control method for a deep peak-shaving coal-fired power generating unit, characterized in that, Applied to a denitrification system, the denitrification system at least includes a denitrification tower, an ammonia injection device connected to the denitrification tower, and an air preheater connected to the denitrification tower, the method comprising: Obtain spectral data of the flue gas mixture at the current moment of the denitrification tower, wherein the flue gas mixture includes at least ammonia and nitrogen oxides; Based on the spectral data, a first predicted concentration and a second predicted concentration are determined using a preset regression model. The first predicted concentration represents the predicted concentration of ammonia escape at the next moment, and the second predicted concentration represents the predicted concentration of nitrogen oxides at the next moment. Based on the first predicted concentration and the second predicted concentration, the ammonia injection rate of the ammonia injection equipment and / or the air volume of the air preheater are controlled.

2. The method according to claim 1, characterized in that, The spectral data includes first spectral data and second spectral data; The first spectral data includes at least one of the following: ammonia molecule spectral line intensity, amino radical spectral line intensity, imino radical spectral line intensity, and hydrogen atom spectral line intensity; The second spectral data includes at least one of the following: nitrogen atom spectral line intensity, oxygen atom spectral line intensity, and nitric oxide molecule spectral line intensity; The step of determining the first predicted concentration and the second predicted concentration based on the spectral data using a preset regression model includes: Based on the first spectral data, the first predicted concentration is determined using the preset regression model; The second predicted concentration is determined using the preset regression model based on the second spectral data.

3. The method according to claim 1, characterized in that, The step of controlling the ammonia injection rate of the ammonia injection equipment and / or the air volume of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection equipment is controlled to adjust the ammonia injection rate according to a preset ammonia reduction strategy; the preset ammonia reduction strategy means that as the first predicted concentration increases, the ammonia injection rate of the ammonia injection equipment decreases at a first preset rate gradient.

4. The method according to claim 1, characterized in that, The step of controlling the ammonia injection rate of the ammonia injection equipment and / or the air volume of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being less than or equal to the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the air preheater is controlled to operate at a first preset airflow rate, and the ammonia injection rate of the ammonia injection device is controlled to increase at a second preset rate gradient.

5. The method according to claim 1, characterized in that, The step of controlling the ammonia injection rate of the ammonia injection equipment and / or the air volume of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being greater than the escaped ammonia concentration threshold and the second predicted concentration being greater than the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection equipment is controlled to be reduced to the first ammonia injection rate threshold, and after a first preset duration, the air preheater is controlled to operate at the second preset airflow rate.

6. The method according to claim 5, characterized in that, The method further includes: If, within a second preset time period after the air preheater starts operating at the second preset air volume, the first predicted concentration decreases and the second predicted concentration increases, the ammonia injection quantity of the ammonia injection equipment is controlled to decrease to a second ammonia injection quantity threshold, where the second ammonia injection quantity threshold is less than the first ammonia injection quantity threshold. If, within a second preset time period after the air preheater starts operating at the second preset airflow, the rate of decrease of the first predicted concentration is greater than a preset speed threshold and the second predicted concentration increases, the ammonia injection equipment is controlled to stop working, and the air preheater is controlled to operate at a third preset airflow, which is greater than the second preset airflow.

7. The method according to claim 1, characterized in that, The step of controlling the ammonia injection rate of the ammonia injection equipment and / or the air volume of the air preheater based on the first predicted concentration and the second predicted concentration includes: In response to the first predicted concentration being less than or equal to the escaped ammonia concentration threshold and the second predicted concentration being less than or equal to the nitrogen oxide concentration threshold, the ammonia injection rate of the ammonia injection equipment and the air volume of the air preheater are both kept unchanged.

8. A denitrification system for a coal-fired power generation unit, characterized in that, The denitrification system includes at least: A denitrification tower, an ammonia injection device connected to the denitrification tower, and an air preheater connected to the denitrification tower; A spectrometer is used to collect spectral data of the flue gas mixture in the denitrification tower, the flue gas mixture comprising at least ammonia and nitrogen oxides; A controller for performing the steps of the method as described in any one of claims 1-7.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the steps of the method described in any one of claims 1-7.

10. An electronic device, characterized in that, include: A memory on which computer programs are stored; A processor for executing the computer program in the memory to implement the steps of the method according to any one of claims 1-7.

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