Method and device for predicting original emission of nitrogen oxide of direct-current burner boiler
By constructing a physical model based on combustion theory and fitting it with coal quality data and historical data, the generation pathway of nitrogen oxides is decomposed, solving the problem of insufficient prediction accuracy in existing technologies, and realizing high-precision prediction and simplified calculation of nitrogen oxide emissions from DC burner boilers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HARBIN BOILER CO LTD
- Filing Date
- 2026-02-28
- Publication Date
- 2026-05-19
AI Technical Summary
Existing technologies for predicting nitrogen oxide emissions from DC burner boilers rely on large-scale data for forced fitting, which lacks theoretical basis, resulting in limited prediction accuracy and insufficient generalization ability, making it difficult to adapt to different coal types and operating conditions.
By acquiring industrial and elemental analysis data of coal types, and combining pyrolysis experiments to obtain the nitrogen content in solids, a physical model based on combustion theory is constructed to calculate the theoretical air volume and flue gas volume. Historical data is used to fit correction coefficients, and nitrogen oxides are decomposed into fuel-type and thermal-type emissions for calculation. Finally, the original emission concentration of nitrogen oxides is synthesized.
It achieves high-precision prediction of nitrogen oxide emission concentration under different coal types and operating conditions, has clear physical meaning and theoretical support, simplifies the calculation process, and is applicable to boiler design and operation optimization.
Smart Images
Figure CN122065727A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pollutant control technology for coal-fired boilers, and more particularly to the field of predicting the original nitrogen oxide emissions of DC burner boilers. Background Technology
[0002] The combustion of coal in power plants generates large amounts of nitrogen oxides (NOx), and their environmental damage has attracted widespread attention. Therefore, monitoring and controlling NOx emissions has become a key focus of environmental protection efforts in the power industry. In the initial design phase of power plant boilers or when existing boilers are planned to switch coal types, the lack of reliable predictions of NOx emission concentrations will pose significant challenges to the design and optimization of pollution control systems. Therefore, developing calculation methods that can accurately predict the initial NOx emission concentration is of great importance for boiler design, fuel selection, and operational adjustments.
[0003] Currently, some research has focused on establishing predictive models for nitrogen oxide emissions. For example, some methods rely on historical operating data and employ numerical fitting techniques such as fractional-order grey time-delay models, online sequential extreme learning machines, or artificial intelligence models. While these models can achieve predictions to some extent, they mostly rely on large amounts of data for training, lack clear physicochemical meaning within the models, have poor interpretability, and limited generalization ability under certain operating conditions. In addition, some simulation methods based on computational fluid dynamics (CFD) can consider in-furnace flow and reaction processes, but they are computationally complex and time-consuming, making them difficult to apply for rapid evaluation and engineering applications.
[0004] Some studies attempt to construct predictive models by incorporating combustion mechanisms, such as establishing dynamic NOx emission models for circulating fluidized bed units. These models incorporate reaction mechanisms to some extent, but they typically still rely on a large number of operating parameters, and their adaptability and simplification remain limited when applied to once-through burner boilers. Overall, existing prediction methods still fall short in balancing theoretical clarity, computational simplicity, and flexibility for different coal types. There is an urgent need for a method for predicting raw NOx emission concentrations that has a clear theoretical basis, requires fewer parameters, and is easily applied in engineering. Summary of the Invention
[0005] This invention proposes a method and apparatus for predicting the raw nitrogen oxide emissions of a DC burner boiler, which solves the problems of limited prediction accuracy caused by the prediction model relying on big data for forced fitting and lacking theoretical basis and physical meaning in the existing technology.
[0006] The method for predicting raw nitrogen oxide emissions from a once-through burner boiler according to the present invention includes the following steps: Step S1: Obtain industrial analysis data and elemental analysis data for the coal type; the industrial analysis data shall include at least moisture and ash content; the elemental analysis data shall include at least carbon, hydrogen, oxygen, nitrogen, and sulfur content. Step S2: Obtain the nitrogen content in the solid; the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. Step S3: Construct coal quality data from the industrial analysis data, elemental analysis data, and nitrogen content in the solid; based on the coal quality data, calculate the theoretical air volume and theoretical flue gas volume for coal combustion; Step S4: Using the theoretical air volume, theoretical flue gas volume, nitrogen content in solids, excess air coefficient, and preset correction coefficient, calculate the concentration of fuel-type nitrogen oxides and the concentration of thermal nitrogen oxides; Step S5: Add the concentrations of fuel-type nitrogen oxides and thermal-type nitrogen oxides to obtain the predicted value of the original nitrogen oxide emission concentration; The preset correction coefficient is determined by fitting historical data; the historical data includes coal quality test results and measured values of original nitrogen oxide emission concentrations from multiple DC burner boilers.
[0007] Furthermore, a preferred embodiment is provided, wherein the theoretical air volume is: ; in, The unit is ; For the carbon content in elemental analysis data, Hydrogen content, For oxygen content, This refers to the sulfur content.
[0008] Furthermore, a preferred embodiment is provided, wherein the theoretical flue gas volume is: ; in, The unit is ; For nitrogen content in elemental analysis data, Hydrogen content, This refers to the moisture content in industrial analysis data.
[0009] Furthermore, a preferred embodiment is provided, wherein the concentration of the fuel-type nitrogen oxides is calculated as follows: ; In the formula: The unit is ; Excess air coefficient; This represents the nitrogen content in the solid. and The preset correction coefficient; where, This is the correction factor for nitrogen in the gas; This is the nitrogen correction factor in solids.
[0010] Furthermore, a preferred embodiment is provided, wherein the nitrogen correction factor in the solid is... : when hour, ; when hour, .
[0011] Furthermore, a preferred embodiment is provided, wherein the concentration of the thermal nitrogen oxides is calculated as follows: ; in, The unit is ; Ash content in industrial analysis data.
[0012] The predicted raw emission concentration of nitrogen oxides is: .
[0013] The present invention also proposes a device for predicting the raw nitrogen oxide emissions of a once-through burner boiler, the device comprising the following modules: Module S1: Acquires industrial analysis data and elemental analysis data for the coal type; the industrial analysis data includes at least moisture and ash content; the elemental analysis data includes at least carbon, hydrogen, oxygen, nitrogen, and sulfur content. Module S2: Obtain the nitrogen content in the solid; the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. Module S3: Constructs coal quality data from the industrial analysis data, elemental analysis data, and nitrogen content in the solid; Based on the coal quality data, calculates the theoretical air volume and theoretical flue gas volume for coal combustion; Module S4: Using the theoretical air volume, theoretical flue gas volume, nitrogen content in solids, excess air coefficient, and preset correction coefficients, calculate the concentration of fuel-type nitrogen oxides and the concentration of thermal nitrogen oxides; Module S5: Add the concentrations of fuel-type nitrogen oxides and thermal-type nitrogen oxides to obtain the predicted value of the original nitrogen oxide emission concentration; The preset correction coefficient is determined by fitting historical data; the historical data includes coal quality test results and measured values of original nitrogen oxide emission concentrations from multiple DC burner boilers.
[0014] The present invention also proposes a computer device comprising: a processor and a memory, the memory for storing executable instructions of the processor, the processor being configured to perform the method for predicting raw nitrogen oxide emissions from a DC burner boiler as described above by executing the executable instructions.
[0015] The present invention also proposes a computer storage medium storing a computer program, wherein when the computer program is executed, it performs the method described above for predicting the raw nitrogen oxide emissions of a DC burner boiler.
[0016] The present invention also proposes a computer program product comprising a computer program / instruction which, when executed by a processor, implements the steps of the method for predicting the raw nitrogen oxide emissions of a DC burner boiler as described in any of the preceding claims.
[0017] The present invention has the following beneficial effects: 1. The method for predicting the original nitrogen oxide emissions of a DC burner boiler described in this invention constructs a physical model based on fuel nitrogen pyrolysis distribution, theoretical air / flue gas volume, and the formation mechanism of fuel-type and thermal NOx by using combustion theory as the core calculation basis. This makes the prediction model have clear physical meaning and theoretical support, overcoming the shortcomings of existing "black box" models that simply rely on big data for forced fitting, which have poor interpretability and weak generalization ability.
[0018] 2. The method described in this invention introduces key correction coefficients (such as nitrogen correction coefficients in gas and nitrogen correction coefficients in solids) determined by fitting historical data to accurately correct the theoretical calculation model. This significantly improves the prediction accuracy and adaptability of the original nitrogen oxide emission concentration of DC burner boilers under different coal types and operating conditions, while ensuring the physical logic of the model.
[0019] 3. The method described in this invention decomposes the complex nitrogen oxide generation process into fuel-type and thermal-type processes for separate calculations, and finally synthesizes the total concentration. This makes the model structure clear and the calculation process relatively simple, which is conducive to rapid prediction and parameter analysis in engineering applications, and provides convenience for boiler design and operation optimization.
[0020] 4. The method described in this invention reduces the reliance on large amounts of real-time operating data or complex testing equipment by relying mainly on relatively easy-to-obtain parameters such as industrial analysis and elemental analysis data of coal quality and nitrogen content in solids obtained through pyrolysis tests. This makes the method easier to implement and apply in the early stages of boiler design or coal type evaluation.
[0021] The method and apparatus for predicting the original nitrogen oxide emissions of a once-through burner boiler described in this invention are applicable to coal-fired power plants in assessing the nitrogen oxide emission potential of different coal types during the boiler design and selection stages, and in rapidly predicting emission changes when changing coal types in existing once-through burner boilers, providing key data support for the configuration and operation optimization of environmental protection facilities. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0023] Figure 1 This is a flowchart of a method for predicting the raw nitrogen oxide emissions of a DC burner boiler, as described in one embodiment of the present invention. Detailed Implementation
[0024] To make the technical solutions and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail and completely below with reference to the accompanying drawings. The various embodiments described below are only some preferred embodiments of the present invention, and not all of them; the various embodiments described below are intended to explain the present invention and should not be construed as limiting the present invention; reasonable combinations of the technical features defined in the various embodiments of the present invention, as well as all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort, are all within the scope of protection of the present invention.
[0025] Implementation Method 1: A method for predicting the raw nitrogen oxide emissions of a once-through burner boiler, the method comprising the following steps: Step S1: Obtain industrial analysis data and elemental analysis data for the coal type; the industrial analysis data shall include at least moisture and ash content; the elemental analysis data shall include at least carbon, hydrogen, oxygen, nitrogen, and sulfur content. Step S2: Obtain the nitrogen content in the solid; the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. Step S3: Construct coal quality data from the industrial analysis data, elemental analysis data, and nitrogen content in the solid; based on the coal quality data, calculate the theoretical air volume and theoretical flue gas volume for coal combustion; Step S4: Using the theoretical air volume, theoretical flue gas volume, nitrogen content in solids, excess air coefficient, and preset correction coefficient, calculate the concentration of fuel-type nitrogen oxides and the concentration of thermal nitrogen oxides; Step S5: Add the concentrations of fuel-type nitrogen oxides and thermal-type nitrogen oxides to obtain the predicted value of the original nitrogen oxide emission concentration; The preset correction coefficient is determined by fitting historical data; the historical data includes coal quality test results and measured values of original nitrogen oxide emission concentrations from multiple DC burner boilers.
[0026] In this embodiment, the method is applied to a DC burner boiler, and the coal type is the designed coal type or the coal fed into the boiler.
[0027] In this embodiment, industrial analysis data and elemental analysis data of the coal type are obtained: Basic chemical analysis is conducted on the coal type designed for coal-fired boilers or the coal fed into the boiler to analyze the industrial and elemental composition of the coal, including moisture, ash, carbon, hydrogen, oxygen, nitrogen, and sulfur.
[0028] In this embodiment, the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. The nitrogen content in the solid represents the proportion of the mass of nitrogen remaining in the solid product after pyrolysis of the coal under set conditions to the total mass of nitrogen in the original coal. The coal was pyrolyzed in a one-dimensional furnace at high temperature. The nitrogen content in the flue gas after pyrolysis was tested, and the total amount of nitrogen elements that migrated into the flue gas after pyrolysis was calculated. Meanwhile, the nitrogen content of the pyrolysis products was analyzed to calculate the total amount of nitrogen remaining in the solid. Based on the mass of nitrogen remaining in the solid and the total nitrogen mass of the raw coal, the distribution ratio of the mass of nitrogen remaining in the solid product to the total nitrogen mass of the raw coal is calculated, i.e., the nitrogen content in the solid.
[0029] In this embodiment, the generation of nitrogen oxides in the boiler mainly includes two aspects: On the one hand, there are fuel-type nitrogen oxides, which are generated by the reaction of nitrogen in fuels with oxygen during combustion. On the other hand, there are thermal nitrogen oxides, which are mainly generated by the reaction of nitrogen in the air with oxygen under high temperature conditions.
[0030] In this embodiment, factors related to nitrogen oxide generation are used as variables. The relevant variables are mainly the carbon, hydrogen, oxygen, nitrogen and sulfur content of coal, moisture and ash content, nitrogen content in solids and excess air coefficient, etc. The preset correction coefficient in the mathematical model is determined by data fitting, and the predicted value of the original emission concentration of nitrogen oxides is calculated.
[0031] In this embodiment, the preset correction coefficient is determined by fitting historical data: Collect coal quality test data and measured values of raw nitrogen oxide emission concentrations from multiple DC burner boilers to form a (historical) dataset; Using the dataset, the preset correction coefficients are fitted through regression analysis or least squares method to make the predicted values... Minimize the error between the measured value and the actual value.
[0032] In this embodiment, the method differs from previous prediction models that mainly relied on big data for forced fitting and lacked theoretical support. This method is based on combustion theory. It performs theoretical calculations by analyzing the influence of different coal quality parameters on nitrogen oxide formation and uses actual data to fit and correct the key coefficients in the model, thereby forming a complete prediction model that has both theoretical basis and empirical support.
[0033] In this embodiment, the method can easily and flexibly predict the original nitrogen oxide emission concentration of once-through burner boilers that burn different types of coal.
[0034] Implementation Method 2: The theoretical air volume: ; in, The unit is ; For the carbon content in elemental analysis data, Hydrogen content, For oxygen content, This refers to the sulfur content.
[0035] Implementation method 3: Theoretical flue gas volume: ; in, The unit is ; For nitrogen content in elemental analysis data, Hydrogen content, This refers to the moisture content in industrial analysis data.
[0036] Implementation Method 4: Calculation of the concentration of nitrogen oxides in the fuel type: ; In the formula: The unit is ; Excess air coefficient; This represents the nitrogen content in the solid. and The preset correction coefficient; where, This is the correction factor for nitrogen in the gas; This is the nitrogen correction factor in solids.
[0037] In this embodiment, the excess air coefficient The value is 1.2, that is .
[0038] In this embodiment, the nitrogen correction factor in the gas The value is 0.07, that is .
[0039] In this embodiment, "gas" in the nitrogen correction coefficient in gas and "solid" in the nitrogen correction coefficient in solid refer to the two forms in which the fuel nitrogen contained in coal is transformed and distributed during high-temperature pyrolysis.
[0040] Nitrogen in solids: refers to the nitrogen element remaining in the solid products (mainly coke) after coal is pyrolyzed at high temperatures.
[0041] Nitrogen in gases: refers to the nitrogen element released from coal and migrated into the volatile gases during the high-temperature pyrolysis of coal.
[0042] The formation pathways and efficiency of fuel-type nitrogen oxides depend on whether the nitrogen in coal exists in the coke or in the volatile matter after pyrolysis. The mechanisms and conversion rates of these two forms of nitrogen in subsequent combustion reactions differ.
[0043] Implementation Method 5: The nitrogen correction factor in the solid is mentioned above. : when hour, ; when hour, .
[0044] In this embodiment, the high parameter range (product ≥ 87): when coal... When the product is large, the data points are displayed. The value exhibits a plateau effect around 0.09, with relatively small fluctuations. This means that within this range, the sensitivity of nitrogen conversion rate in the solids to changes in coal quality decreases, reaching a relatively stable state. At this point, using a constant (0.09) is the "sufficiently accurate and simplest" engineering choice, avoiding unnecessary complex calculations.
[0045] In this embodiment, the low parameter range (product < 87): when the product is small... The relationship between the value and the product exhibits a strong non-linearity, and using a simple constant will introduce significant errors. In this case, using a negative exponential function can better capture the problem. The trend of rapidly increasing as the product of coal quality parameters decreases significantly improves prediction accuracy.
[0046] Implementation Method 6: Calculation of the concentration of the thermal nitrogen oxides: ; in, The unit is ; Ash content in industrial analysis data.
[0047] The predicted raw emission concentration of nitrogen oxides is: .
[0048] Implementation Method 7: A device for predicting the raw nitrogen oxide emissions of a once-through burner boiler, the device comprising the following modules: Module S1: Acquires industrial analysis data and elemental analysis data for the coal type; the industrial analysis data includes at least moisture and ash content; the elemental analysis data includes at least carbon, hydrogen, oxygen, nitrogen, and sulfur content. Module S2: Obtain the nitrogen content in the solid; the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. Module S3: Constructs coal quality data from the industrial analysis data, elemental analysis data, and nitrogen content in the solid; Based on the coal quality data, calculates the theoretical air volume and theoretical flue gas volume for coal combustion; Module S4: Using the theoretical air volume, theoretical flue gas volume, nitrogen content in solids, excess air coefficient, and preset correction coefficients, calculate the concentration of fuel-type nitrogen oxides and the concentration of thermal nitrogen oxides; Module S5: Add the concentrations of fuel-type nitrogen oxides and thermal-type nitrogen oxides to obtain the predicted value of the original nitrogen oxide emission concentration; The preset correction coefficient is determined by fitting historical data; the historical data includes coal quality test results and measured values of original nitrogen oxide emission concentrations from multiple DC burner boilers.
[0049] Embodiment 8: A computer device comprising: a processor and a memory, the memory for storing executable instructions of the processor, the processor being configured to perform, by executing the executable instructions, the method for predicting raw nitrogen oxide emissions from a DC burner boiler as described in any of the above embodiments.
[0050] Implementation Method 9: A computer storage medium storing a computer program, wherein when the computer program is executed, it performs the method for predicting the raw nitrogen oxide emissions of a DC burner boiler as described in any one of the above implementation methods.
[0051] Implementation 10: A computer program product comprising a computer program / instructions that, when executed by a processor, implement the steps of the method for predicting the raw nitrogen oxide emissions of a DC burner boiler as described in any of the above embodiments.
[0052] The above description of several specific embodiments further details the technical solution provided by the present invention in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the above-described specific embodiments are not intended to limit the present invention. Any reasonable modifications and improvements to the present invention, reasonable combinations of embodiments, and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for predicting the raw nitrogen oxide emissions of a once-through burner boiler, characterized in that, The method includes the following steps: Step S1: Obtain industrial analysis data and elemental analysis data for the coal type; the industrial analysis data shall include at least moisture and ash content; the elemental analysis data shall include at least carbon, hydrogen, oxygen, nitrogen, and sulfur content. Step S2: Obtain the nitrogen content in the solid; the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. Step S3: Construct coal quality data from the industrial analysis data, elemental analysis data, and nitrogen content in the solid; based on the coal quality data, calculate the theoretical air volume and theoretical flue gas volume for coal combustion; Step S4: Using the theoretical air volume, theoretical flue gas volume, nitrogen content in solids, excess air coefficient, and preset correction coefficient, calculate the concentration of fuel-type nitrogen oxides and the concentration of thermal nitrogen oxides; Step S5: Add the concentrations of fuel-type nitrogen oxides and thermal-type nitrogen oxides to obtain the predicted value of the original nitrogen oxide emission concentration; The preset correction coefficient is determined by fitting historical data; the historical data includes coal quality test results and measured values of original nitrogen oxide emission concentrations from multiple DC burner boilers.
2. The method for predicting raw nitrogen oxide emissions from a once-through burner boiler according to claim 1, characterized in that, The theoretical air volume mentioned above: ； in, The unit is ; The carbon content in the elemental analysis data. Hydrogen content, For oxygen content, This refers to the sulfur content.
3. The method for predicting raw nitrogen oxide emissions from a once-through burner boiler according to claim 1, characterized in that, The theoretical flue gas volume: ； in, The unit is ; For nitrogen content in elemental analysis data, Hydrogen content, This refers to the moisture content in industrial analysis data.
4. The method for predicting raw nitrogen oxide emissions from a once-through burner boiler according to claim 1, characterized in that, The calculation of the concentration of nitrogen oxides in the fuel type: ； In the formula: The unit is ; Excess air coefficient; This represents the nitrogen content in the solid. and The preset correction coefficient; where, This is the correction factor for nitrogen in the gas; This is the nitrogen correction factor in solids.
5. The method for predicting raw nitrogen oxide emissions from a once-through burner boiler according to claim 1, characterized in that, The term refers to the nitrogen correction factor in solids. : when hour, ; when hour, .
6. The method for predicting raw nitrogen oxide emissions from a once-through burner boiler according to claim 1, characterized in that, Calculation of the thermal nitrogen oxide concentration: ； in, The unit is ; Ash content in industrial analysis data. The predicted raw emission concentration of nitrogen oxides is: 。 7. A device for predicting the raw nitrogen oxide emissions of a once-through burner boiler, characterized in that, The device includes the following modules: Module S1: Acquires industrial analysis data and elemental analysis data for the coal type; the industrial analysis data includes at least moisture and ash content; the elemental analysis data includes at least carbon, hydrogen, oxygen, nitrogen, and sulfur content. Module S2: Obtain the nitrogen content in the solid; the nitrogen content in the solid is obtained after conducting a pyrolysis test on the coal. Module S3: Constructs coal quality data from the industrial analysis data, elemental analysis data, and nitrogen content in the solid; based on the coal quality data, calculates the theoretical air volume and theoretical flue gas volume for coal combustion; Module S4: Using the theoretical air volume, theoretical flue gas volume, nitrogen content in solids, excess air coefficient, and preset correction coefficients, calculate the concentration of fuel-type nitrogen oxides and the concentration of thermal nitrogen oxides; Module S5: Add the concentrations of fuel-type nitrogen oxides and thermal-type nitrogen oxides to obtain the predicted value of the original nitrogen oxide emission concentration; The preset correction coefficient is determined by fitting historical data; the historical data includes coal quality test results and measured values of original nitrogen oxide emission concentrations from multiple DC burner boilers.
8. A computer device, comprising: A processor and a memory, characterized in that the memory is used to store executable instructions of the processor, the processor being configured to perform the method for predicting raw nitrogen oxide emissions from a DC burner boiler according to any one of claims 1-6 by executing the executable instructions.
9. A computer storage medium, characterized in that, The storage medium stores a computer program, which, when executed, performs the method for predicting the raw nitrogen oxide emissions of a DC burner boiler as described in any one of claims 1-6.
10. A computer program product comprising a computer program / instructions, characterized in that, When executed by a processor, the computer program / instructions implement the steps of the method for predicting the raw nitrogen oxide emissions of a DC burner boiler as described in any one of claims 1-6.