A reverse intelligent control burner based on flue gas composition analysis

Abstract

This invention discloses a reverse intelligent control burner based on flue gas composition analysis, belonging to the field of intelligent burner control technology. It includes a flue gas detection device, a combustion controller, and an actuator that are sequentially linked to form a closed-loop control circuit. The flue gas detection device collects real-time parameters of carbon monoxide, nitrogen monoxide, and oxygen content in the flue gas during burner operation and transmits these parameters to the combustion controller. The combustion controller presets a fixed fuel-air ratio baseline, an air volume and backflow regulating valve opening adjustment range, and a rigid carbon monoxide constraint of 20 mg / m³. Within this constraint range, it obtains the real-time nitrogen oxide concentration based on the flue gas parameters and generates a coordinated fine-tuning command to regulate nitrogen oxide emissions by reducing air volume and increasing backflow. The actuator receives the coordinated fine-tuning command and drives the air valve and backflow regulating valve to perform corresponding opening adjustments. This invention balances environmental protection and energy conservation with combustion stability, achieving reduced air volume and backflow for nitrogen reduction under full combustion.

Description

Technical Field

[0001] This invention belongs to the field of intelligent burner control technology, specifically a reverse intelligent control burner based on flue gas composition analysis. Background Technology

[0002] In industrial production, burners, as core equipment for energy conversion, directly impact environmental compliance, production efficiency, and equipment safety through their pollutant emission control, energy consumption optimization, and combustion stability. The ratio of fuel gas to air is a key factor influencing combustion. A fixed air-fuel ratio ensures basic combustion stability and is a common benchmark strategy for industrial burner operation. However, traditional applications lack supporting nitrogen oxide (NOx) range control mechanisms and do not incorporate backflow control valves. Relying solely on airflow adjustment makes precise NOx control difficult, failing to reduce airflow while ensuring complete combustion, and hindering effective NOx emission reduction through backflow control.

[0003] Traditional burner control methods have significant shortcomings, which are manifested in the following aspects:

[0004] First, a fixed air-fuel ratio benchmark has not been established, or although there is a fixed ratio, no upper and lower adjustment range based on the initial value has been set for the air volume. Some technologies use dynamic air-fuel ratio adjustment without a clear initial benchmark and range limit. Either the fixed ratio cannot cope with small fluctuations in nitrogen oxides, resulting in excessive emissions, or the lack of range limit allows for large-scale air volume adjustment, which destroys combustion stability and causes excessive carbon monoxide.

[0005] Secondly, the adjustment mechanism is lagging behind, mostly passive feedback adjustment, and no back smoke regulating valve is set up for coordinated control. The aforementioned comparative patents and industry standards do not involve back smoke coordinated control, and only adjust the air volume. It is impossible to achieve the goal of "reducing the air volume under the premise of ensuring complete combustion and reducing nitrogen oxides by using back smoke". It is difficult to balance the stability of the fixed ratio, the flexibility of nitrogen oxide emission reduction and the energy saving requirements. Moreover, its oxygen content control accuracy is only ±1.5% VOL, which cannot meet the stringent emission requirements.

[0006] Therefore, there is an urgent need for an intelligent control system and method that is based on a fixed air-fuel ratio, combines coordinated range-based fine-tuning of air volume and smoke return volume, and achieves nitrogen oxide emission reduction by "reducing air and increasing smoke return", with carbon monoxide ≤20mg / m³ as a prerequisite, to solve the above technical problems. Summary of the Invention

[0007] To address the shortcomings of existing burner control technologies, such as the lack of a fixed air-fuel ratio benchmark, the absence of an adjustment range based on the initial air volume, poor coordination among multiple parameters, the lack of a backflow regulating valve for coordinated control, the difficulty in balancing combustion stability with emission reduction and energy saving, and the inability to achieve "reducing air volume while ensuring complete combustion and reducing nitrogen oxides through backflow," this invention aims to provide a reverse intelligent control burner based on flue gas composition analysis.

[0008] This invention establishes a fixed ratio benchmark value for gas and air (corresponding to the initial air volume value), and sets upper and lower adjustment ranges for air volume and flue gas regulating valve opening based on the initial values ​​(with a uniform fine-tuning range of 10%). Under the premise of strictly ensuring that the carbon monoxide content is consistently less than 20 mg / m³, nitrogen oxides are reduced by decreasing the air volume and increasing the flue gas volume according to the real-time nitrogen oxide concentration. Ultimately, this achieves the triple goals of low nitrogen emissions, significant energy saving, and stable combustion of the burner, improves energy utilization efficiency, meets the multiple high standards of environmental protection, energy saving, and stable operation required by industrial production, and reduces equipment operation and maintenance costs.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] A reverse intelligent control burner based on flue gas composition analysis includes a flue gas detection device, a combustion controller, and an actuator that are sequentially linked by signals to form a closed-loop control circuit.

[0011] The flue gas detection device is used to collect parameters of carbon monoxide, nitrogen monoxide and oxygen content in the flue gas of the burner in real time, and transmit the collected parameters to the combustion controller.

[0012] The combustion controller is preset with a fixed ratio of gas to air, an air volume adjustment range corresponding to the initial air volume, an opening adjustment range corresponding to the initial opening of the back smoke regulating valve, a rigid constraint value of 20 mg / m³ carbon monoxide content, and an oxygen reference value set simultaneously.

[0013] Within the limit of the rigid carbon monoxide constraint value, the combustion controller obtains the real-time concentration of nitrogen oxides based on the received flue gas parameters, generates a coordinated fine-tuning command for air volume and flue gas return volume, and regulates nitrogen oxide emissions by reducing air volume and increasing flue gas return volume.

[0014] The actuator receives the coordinated fine-tuning command and drives the air valve and the smoke return regulating valve to perform corresponding opening adjustments.

[0015] As a further improvement to the above scheme, the flue gas detection device adopts a composite detection scheme combining non-dispersive infrared technology and electrochemical sensing. Non-dispersive infrared technology is used to detect carbon monoxide, with a measurement range of 0-1000 mg / m³ and an accuracy of ±2%FS. A high-sensitivity electrochemical sensor is used to detect nitric oxide and oxygen content, with a nitric oxide measurement range of 0-1000 ppm and an accuracy of ±3%FS, and an oxygen content measurement range of 0-25%VOL and an accuracy of ±1%VOL. The detection device transmits real-time multi-parameter flue gas data (focusing on nitric oxide, carbon monoxide, and oxygen content) to the combustion controller via RS485 (Modbus RTU) communication protocol at a transmission frequency of 20 times / second. This provides accurate and timely data support for subsequent interval determination and coordinated fine-tuning of air volume and flue gas return volume, with a focus on ensuring the accuracy of carbon monoxide data detection, ensuring that carbon monoxide is ≤20 mg / m³.

[0016] As a further improvement to the above solution, the combustion controller integrates a benchmark preset module, a data preprocessing module, a parameter calculation module, a concentration determination module, an instruction generation module, and a smoke return regulating valve control module. The smoke return regulating valve control module consists of an ARM processor, a PLC control unit, and an instruction calculation module, and it has a custom-developed intelligent control algorithm software built in.

[0017] The core preset fixed ratio of gas to air is a baseline value (which can be flexibly set according to the burner model and fuel type, such as 1:10, 1:12, corresponding to the initial air volume value), and the preset initial opening of the back smoke regulating valve is a preset value (which can be flexibly set according to the operating conditions, such as 30%-50%). In addition, according to industry emission standards and combustion conditions, the upper and lower adjustment ranges of air volume and back smoke regulating valve opening are preset (all based on their respective initial values, and the single fine adjustment range is uniformly 10%).

[0018] As a further improvement to the above solution, the parameter calculation module calculates the nitrogen oxide concentration and reference oxygen conversion value using a preset formula. The calculation formula is as follows: Where NO represents the measured concentration of nitric oxide. To preset the oxygen reference value, This is the measured value of oxygen content.

[0019] The combustion controller, based on the premise that the measured carbon monoxide value is ≤20mg / m³ and the fuel is fully combusted, generates corresponding adjustment commands according to the nitrogen oxide concentration to adjust the air volume and the opening of the smoke return regulating valve.

[0020] Based on the fixed air-gas ratio benchmark and the preset initial opening of the flue gas regulating valve, a coordinated fine-tuning command is generated according to the real-time nitrogen oxide concentration and the reference oxygen conversion value. The single fine-tuning range is uniformly 10% to avoid drastic adjustments that could disrupt combustion stability. The core logic follows the principle of "reducing air volume and increasing flue gas volume to lower nitrogen oxides while ensuring complete combustion and carbon monoxide ≤20mg / m³". The specific command logic is as follows:

[0021] If the concentration of nitrogen oxides is too high: under the premise of ensuring that carbon monoxide is ≤20mg / m³ and complete combustion, slightly reduce the air volume within the lower limit of the initial air volume value, with a fine adjustment range of ≤10%, and simultaneously increase the return smoke volume within the preset range of the return smoke regulating valve, with a slight increase in the return smoke regulating valve and a fine adjustment range of ≤10%. By increasing the return smoke volume, nitrogen oxide emissions are reduced, and energy is saved by reducing the air volume.

[0022] If the nitrogen oxide concentration meets the standard: under the premise of ensuring complete combustion and carbon monoxide ≤20mg / m³, slightly reduce the air volume within the upper and lower range of the air volume, with the fine adjustment range ≤3%, and simultaneously fine adjust the return smoke regulating valve to maintain the return smoke volume to further improve the energy saving effect;

[0023] If the nitrogen oxide concentration is too low: maintain the initial air volume and the initial opening of the smoke return regulating valve unchanged to ensure complete combustion, optimal energy consumption, and carbon monoxide ≤20mg / m³.

[0024] Commands are transmitted via 4-20mA signals with a response time of less than 100ms, ensuring accurate and timely adjustment.

[0025] As a further improvement to the above solution, the actuator includes a servo motor driver, an air valve actuator, and a smoke return regulating valve actuator. The core mechanism works in conjunction with the combustion controller to achieve precise and coordinated fine-tuning of the air volume and smoke return volume, with a uniform fine-tuning range of 10%. This implements the NOx control strategy of "reducing air and increasing smoke return": after receiving fine-tuning commands transmitted via 4-20mA, the servo motor driver drives the air valve actuator and the smoke return regulating valve actuator to operate precisely. The PLC control unit adopts a graded fine-tuning strategy, using the initial air volume value corresponding to a fixed air-fuel ratio and the initial opening of the smoke return regulating valve as a benchmark. Within their respective preset upper and lower adjustment ranges, the fine-tuning range is 10%, with step adjustments in increments not exceeding 5%, to avoid sudden changes in air volume and smoke return volume that could disrupt combustion stability, ensuring complete combustion and carbon monoxide ≤20mg / m³. The air valve is a high-precision electric butterfly valve with an opening adjustment range of 0-100% and an adjustment accuracy of ±0.5%. The smoke return regulating valve is a high-precision electric regulating valve with an opening adjustment range of 0-100% and an adjustment accuracy of ±0.5%. This ensures a smooth fine-tuning process when the air volume decreases and the smoke return volume increases, achieving precise control of nitrogen oxides while maintaining stable combustion and ensuring complete combustion.

[0026] A control method for a reverse intelligent control burner based on flue gas composition analysis includes the following steps:

[0027] S1 Preset: Presets the fixed ratio of gas and air volume to a reference value, the air volume adjustment range corresponding to the initial air volume value, where the fine adjustment range is uniformly 10%, and the opening adjustment range corresponding to the initial opening of the back smoke regulating valve, where the fine adjustment range is uniformly 10%, as well as a rigid constraint value of 20mg / m³ carbon monoxide content and simultaneously sets the oxygen reference value.

[0028] S2 Data Acquisition: The flue gas detection device continuously collects the flue gas generated during the burner operation at a frequency of 20 times / second, and simultaneously acquires three core parameters: nitric oxide, carbon monoxide, and oxygen content. It then transmits the data to the combustion controller in a timely manner via the RS485 (Modbus RTU) communication protocol, ensuring that the data acquisition is complete and the transmission is timely. It focuses on ensuring the real-time monitoring of carbon monoxide data and ensures that carbon monoxide is ≤20mg / m³.

[0029] S3 Rigid Constraint Judgment: Compare the measured carbon monoxide value with the rigid constraint value of 20 mg / m³. If the measured value exceeds the standard, adjust the air volume and smoke return volume to meet the standard before proceeding to the next step.

[0030] S4 Nitrogen Oxide Concentration Determination: Based on the collected flue gas parameters, the real-time nitrogen oxide concentration is obtained, and the direction and magnitude of the fine adjustment of the air volume and the return smoke regulating valve are determined.

[0031] Based on the actual measured values ​​of nitric oxide and oxygen content, the nitrogen oxide concentration and reference oxygen conversion value are calculated according to the preset formula. The direction and amplitude of the fine adjustment of the air volume and the smoke return regulating valve are determined to ensure that the fine adjustment range of both does not exceed their respective preset upper and lower adjustment ranges. The fine adjustment amplitude is 10%, while taking into account the requirements of complete combustion and carbon monoxide ≤20mg / m³.

[0032] S5 Coordinated Regulation Execution: Under the premise that the carbon monoxide content does not exceed 20 mg / m³, a coordinated fine-tuning instruction is generated based on the judgment result, and nitrogen oxide emissions are controlled by reducing the air volume and increasing the amount of smoke returned.

[0033] S6 closed-loop feedback optimization: continuously monitors flue gas parameters and valve opening, feeds back the adjustment results in real time, dynamically optimizes the fine-tuning range, and maintains stable system operation.

[0034] Specifically, the combustion controller continuously monitors flue gas composition data (with a focus on carbon monoxide and nitrogen monoxide), air valve opening, and back smoke regulating valve opening. It analyzes and processes the data every 100ms, and feeds back the adjusted nitrogen oxide and carbon monoxide concentrations and their openings to the judgment stage in real time. The fine-tuning range is dynamically optimized and is always ≤10%, ensuring that the air volume and back smoke regulating valve opening are always within their respective preset upper and lower ranges, carbon monoxide ≤20mg / m³, nitrogen oxide concentration is maintained within a reasonable range, and the burner is always in a state of complete combustion, high efficiency, stability, and low nitrogen emissions.

[0035] As a further improvement to the above scheme, S5 executes the following instruction generation logic based on the nitrogen oxide concentration. The specific instruction logic is as follows:

[0036] If the nitrogen oxide concentration is higher than the preset threshold, the air volume will be reduced within the adjustment range of the initial air volume value, with the reduction not exceeding 10%. At the same time, the valve opening of the smoke return regulating valve will be increased within the adjustment range, with the increase not exceeding 10%.

[0037] If the nitrogen oxide concentration is within the preset acceptable range, reduce the air volume within the air volume adjustment range, with the reduction not exceeding 3%, while simultaneously maintaining a stable opening of the smoke return regulating valve;

[0038] If the nitrogen oxide concentration is lower than the lower limit of the preset compliance range, maintain the initial value of the air volume and the initial opening of the smoke return regulating valve unchanged.

[0039] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0040] Compared with existing technologies, this invention has the following significant advantages: it balances environmental protection, energy conservation, and combustion stability, achieving the goal of "reducing air volume and using flue gas to reduce nitrogen oxides while ensuring complete combustion," and is highly practical.

[0041] (1) Precise and efficient emission control: By ensuring stable and complete combustion through a fixed air-fuel ratio benchmark, and by adding a collaborative control mechanism with a back-smoke regulating valve, combined with fine-tuning of the initial values ​​of air volume and back-smoke volume within the upper and lower ranges (with a uniform range of 10%), under the premise of strictly ensuring carbon monoxide ≤20mg / m³, the nitrogen oxide emissions are precisely controlled through the strategy of "reducing air and increasing back-smoke", which completely solves the pain point that traditional and existing technologies cannot simultaneously achieve complete combustion, energy saving and nitrogen oxide emission reduction. Actual operation tests show that the nitrogen oxide concentration is maintained within a reasonable range, and the opening of the air volume and back-smoke regulating valve is always finely adjusted within the preset range. The oxygen content control accuracy of this invention reaches ±1% VOL, which is 33% higher than the existing technology (±1.5% VOL), far exceeding the requirements of the existing technology and industry standard GB / T 19237-2021, and can easily meet the current stringent environmental emission requirements.

[0042] (2) Significant energy saving and consumption reduction effect: Strictly implement the goal of "reducing air volume under the premise of ensuring complete combustion", and rely on the initial value of air volume corresponding to a fixed air-fuel ratio. Within a preset range (fine adjustment range of 10%), the air volume is slightly reduced. At the same time, the nitrogen oxides are reduced by increasing the amount of flue gas, avoiding the heat loss of flue gas caused by excessive air, and ensuring complete combustion of fuel and optimal energy consumption. According to actual industrial application verification, compared with the traditional burner control method, the present invention can reduce the energy consumption of burners by 5-10%. For example, in the application of industrial hot blast stove in a large steel plant, the fuel consumption per hour was 1,000 kg before the modification, and it was reduced to 920 kg after adopting this system. In the application scenario of hot blast stove in chemical plant, the efficiency is improved by 15% and the fuel consumption is reduced by 8%, with outstanding energy saving benefits.

[0043] (3) Significantly improved combustion stability: The innovative control logic of "fixed air-fuel ratio (initial air volume) + flue gas baseline + dual-range coordinated fine-tuning (amplitude 10%)" is adopted. The core follows the control strategy of "reducing air and increasing flue gas". It not only maintains the operational stability of the fixed air-fuel ratio and ensures complete combustion, but also solves the flexibility problem of nitrogen oxide emission reduction through coordinated fine-tuning of air volume and flue gas. It effectively avoids problems such as combustion instability, equipment carbon buildup, and overheating caused by large fluctuations in air volume and flue gas. From data acquisition to control command issuance, the overall response time is shortened to 0.5 seconds, eliminating the need for frequent manual intervention and reducing manual operation and maintenance costs.

[0044] (4) Outstanding equipment reliability and adaptability: Through precise coordinated fine-tuning (amplitude 10%) within the upper and lower ranges of the initial values ​​of air volume and return smoke volume, and fixed ratio control, the wear and tear of equipment caused by unstable combustion is effectively reduced. Actual operation statistics show that the failure rate of burners and related equipment is reduced by 30%, which can significantly extend the service life of equipment and reduce equipment maintenance costs. At the same time, the fixed air-fuel ratio benchmark value (initial value of air volume), the upper and lower adjustment range of air volume, the initial opening degree of the return smoke regulating valve and the upper and lower adjustment range can be flexibly preset according to different industrial working conditions to adapt to the complex operating needs of various industrial combustion equipment, and have significant economic and social benefits. Attached Figure Description

[0045] Figure 1 This is a flowchart of the intelligent control system for the burner based on flue gas composition analysis and reverse intelligent control as described in this invention.

[0046] Figure 2 This is a functional architecture diagram of the combustion controller described in this invention;

[0047] Figure 3 This is a schematic diagram of the intelligent control process of the burner based on flue gas composition analysis and reverse intelligent control according to the present invention. Detailed Implementation

[0048] To enable those skilled in the art to better understand the technical solution, the present invention will be described in detail below with reference to embodiments. The description in this part is only exemplary and explanatory, and should not be used to limit the scope of protection of the present invention in any way.

[0049] The present invention relates to a flue gas composition analysis-based reverse intelligent control burner, which consists of three main parts: a flue gas detection device, a combustion controller, and an actuator. The flue gas detection device and the combustion controller are connected via a high-speed communication protocol, and the combustion controller and the actuator are linked by signals to form a closed-loop intelligent control system of "baseline ratio determination - interval judgment - collaborative fine-tuning". This ensures the real-time transmission of data and the accuracy of control commands. The core objective is to "reduce air volume while ensuring complete combustion, reduce nitrogen oxides by using back flue gas, and keep carbon monoxide ≤20mg / m³ as a prerequisite".

[0050] Example 1 is an example of low-NOx combustion control in a 300,000 kcal natural gas industrial hot blast stove.

[0051] This embodiment applies to a 300,000 kcal / kg natural gas industrial hot blast stove in a steel plant. The equipment originally used a traditional manual adjustment mode, which resulted in NO... x To address issues such as excessive emission fluctuations, high flue gas heat loss due to excess air, and insufficient combustion stability, the system and method of this invention were used for modification. A 72-hour continuous operation test was completed, verifying the feasibility and technical effectiveness of the invention. The system flowchart for this embodiment is attached to the instruction manual. Figure 1For the control logic flow, please refer to the attached manual. Figure 3 For the functional architecture of the combustion controller, please refer to the instruction manual appendix. Figure 2 .

[0052] 1. System hardware and baseline parameter presets

[0053] The low-NOx combustion intelligent control system in this embodiment consists of three parts: a flue gas detection device, a combustion controller, and an actuator, which are linked sequentially to form a closed-loop control. The hardware configuration and core parameters are preset as follows:

[0054] Flue gas detection device: It uses non-dispersive infrared (NDIR) technology to detect CO, with a measurement range of 0-1000 mg / m³ and an accuracy of ±2%FS; it uses a high-sensitivity electrochemical sensor to detect nitric oxide (NO) and oxygen content, with a NO measurement range of 0-1000ppm and an accuracy of ±3%FS, and an oxygen content measurement range of 0-25%VOL and an accuracy of ±1%VOL; the detection device transmits real-time data to the combustion controller at a frequency of 20 times / second via RS485 (Modbus RTU) communication protocol.

[0055] Combustion controller: Employs a high-performance ARM processor + PLC control unit, with a built-in adaptive fuzzy PID control algorithm and a newly added flue gas regulating valve control module; core parameters are preset as follows, and all parameters are set in conjunction with the rated power of the hot blast stove, the characteristics of natural gas fuel, and local environmental protection requirements:

[0056] The fixed ratio of natural gas to air is 1:10 (natural gas has a lower calorific value of 36 MJ / m³, a theoretical air-fuel ratio of 9.5:1, and a 5% safety margin is set at 1:10), corresponding to an initial air volume of 348.8 Nm³ / h. The air volume can be adjusted within ±10% of the initial value (313.9-383.7 Nm³ / h).

[0057] The initial opening of the smoke return regulating valve is 30%, and the upper and lower adjustment range of the opening is ±10% (20%-40%) of the initial value.

[0058] The rigid limit for CO is 20 mg / m³, and the baseline oxygen content is... =3%VOL, The compliance threshold is ≤50mg / m³ (meets the local industrial furnace and kiln air pollutant emission standards).

[0059] Actuators include a servo motor driver, an air valve actuator (electric butterfly valve), and a smoke control valve actuator (electric regulating valve); the opening range of both valves is 0-100%, with an adjustment accuracy of ±0.5%; the servo motor driver receives a 4-20mA analog signal from the combustion controller and drives the valve to perform step-wise adjustment in steps not exceeding 5%, with a command response time ≤100ms.

[0060] 2. Step-by-step numerical calculation and result determination of core formulas

[0061] All control actions in this embodiment are based on the formula calculation results and strictly follow national environmental accounting standards. The following uses the measured flue gas data of the control mode of this invention for 1 hour to complete the step-by-step numerical calculation of the whole process, and clarifies the specific application of the formula and the result judgment logic:

[0062] Actual measured basic data:

[0063] The measured NO concentration was 20.76 ppm, and the oxygen content was... The measured values ​​were 4.9% VOL and 12 mg / m³ CO.

[0064] Formula (1): Calculation of nitrogen oxide volume concentration:

[0065] ;

[0066] Numerical substitution calculation:

[0067]

[0068] Calculation Explanation: The coefficient 1.03 represents the proportion of NO in the total flue gas from gas combustion. Volume ratio conversion factor (NO percentage in gas combustion) The proportion is approximately 97%, which is in line with the general practice of the domestic flue gas monitoring industry.

[0069] Formula (2): Calculation of nitrogen oxide mass concentration after conversion from baseline oxygen content:

[0070] Step-by-step numerical substitution calculation:

[0071] First, calculate the conversion factor for the baseline oxygen content:

[0072] Calculation Notes: 21 represents the standard volume percentage of oxygen in dry air. This coefficient is used to convert measured values ​​under different excess air coefficients. The concentration is uniformly converted to the standard emission concentration under the baseline oxygen content of 3% VOL, which complies with the statutory accounting requirements of the "Emission Standard of Air Pollutants for Boilers" (GB13271-2014).

[0073] Then complete the final mass concentration calculation:

[0074] Calculation Notes: The coefficient 2.05 represents the nitrogen dioxide concentration under standard conditions (0℃, 101.325kPa) (in environmental accounting). Unified with Legal conversion factor between ppm and mg / m³ (calculated) .

[0075] Calculation result verification and control direction determination:

[0076] Rigid constraint verification: The measured CO value is 12mg / m³ < 20mg / m³, which meets the rigid premise of complete fuel combustion. The calculation results are valid and can proceed to the subsequent control and judgment stage.

[0077] Emissions compliance determination: calculated The baseline oxygen conversion value is 49 mg / m³, which is within the preset compliance range of ≤50 mg / m³. No major adjustments are required; only a small reduction of ≤3% in air volume is needed for energy saving.

[0078] Compliance determination of the range: This fine-tuning action must be controlled within the preset ±10% range of air volume and smoke return valve opening, and must not be adjusted beyond the range.

[0079] 3. This embodiment strictly follows the six core steps of the control method of the present invention to form a complete closed-loop control. The specific steps are as follows:

[0080] S1 baseline preset: The combustion controller presets the core parameters such as air-fuel ratio, adjustment range, CO constraint value, and oxygen reference value, solidifying the principle of "ensuring complete combustion and CO ≤ 20mg / m³ while reducing air intake and increasing backflow smoke." The regulatory logic is "".

[0081] S2 Real-time Data Acquisition: The flue gas detection device continuously collects three core parameters—NO, CO, and oxygen content—in the combustion flue gas of the hot blast stove and transmits them to the combustion controller at a frequency of 20 times per second. The combustion controller purifies the raw data, eliminating abnormal data outliers caused by electromagnetic interference and temperature fluctuations in the industrial environment, ensuring the validity of the data.

[0082] S3 Rigid Constraint Priority Determination: The combustion controller compares the measured CO value with the constraint upper limit of 20 mg / m³ in real time. In this embodiment, the measured CO value is below 20 mg / m³ throughout the normal operating conditions, so it directly proceeds to the next step. Control process; Supplementary verification under abnormal operating conditions: During the test, a scenario of excessive CO was simulated (measured value 26 mg / m³), and the combustion controller immediately stopped. For adjustment, prioritize increasing the air volume and decreasing the smoke return valve opening in 1% increments until the measured CO value drops to 18 mg / m³ and stabilizes, then restore the original settings. The calculation and coordinated regulation fully comply with the core rule of prioritizing rigid constraints.

[0083] S4 Full-process numerical calculation and concentration determination: The combustion controller completes the full-process numerical calculation of the measured data at each monitoring time point according to the above formulas (1) and (2), and finally determines the air volume and the fine adjustment direction and amplitude of the return smoke valve in combination with the preset ±10% adjustment range.

[0084] S5 Coordinated Fine-Tuning Execution: Based on the initial air volume value corresponding to a fixed air-fuel ratio and the initial opening degree of the smoke return valve, combined with... The numerical calculation results follow the logic of "reducing air volume and increasing smoke return," and are adjusted in a step-by-step, differentiated manner with a increment of ≤5%, as follows:

[0085] when When the calculated value is >50mg / m³ (too high), within the lower limit of the initial air volume value, the air volume is reduced by ≤10% in multiple increments of 2%, and the back smoke regulating valve is opened by ≤10% in multiple increments of 2%. The CO concentration is checked after each adjustment to ensure that the rigid constraint is not exceeded.

[0086] when When the calculated value is between 30-50 mg / m³ (compliant range), the air volume is reduced slightly in increments of ≤1.5%, and the return smoke regulating valve is adjusted simultaneously to maintain a stable return smoke volume, thereby further reducing exhaust heat loss.

[0087] when When the calculated value is less than 30 mg / m³ (too low), maintain the initial air volume and the initial opening of the return smoke valve unchanged to ensure complete fuel combustion.

[0088] S6 Closed-Loop Feedback Optimization: The combustion controller monitors and analyzes flue gas parameters and valve opening every 100ms, and re-executes the process after fine-tuning the flue gas parameters. The entire process involves numerical calculations, and the results are fed back to the concentration determination stage in real time. The dynamic optimization and fine-tuning range ensures that the air volume and the opening of the return smoke valve are always within the preset ±10% range, and the overall system control response time is ≤0.5 seconds.

[0089] 4.72-hour full-cycle test data and numerical calculation results

[0090] This embodiment completes 72 hours of continuous operation monitoring, simultaneously collecting raw operational data from both the traditional manual adjustment mode and the control mode of this invention, and completing the measured data at each monitoring time point. The results of the full-process numerical calculation are shown in Table 1, and the average values ​​of the core indicators are shown in Table 2.

[0091]

[0092]

[0093] 5. Conclusion of the Example

[0094] This embodiment fully reproduces all the technical solutions of the present invention, and the verification results are as follows:

[0095] Feasibility verification: Those skilled in the art can fully reproduce the control effect of the present invention based on the parameter configuration, control process, and calculation method of this embodiment, thus meeting the requirement of "sufficient disclosure" under the patent law;

[0096] Technical effect verification: The mode of this invention achieves the following while ensuring CO ≤ 20 mg / m³ throughout the entire process: The average emission reduction is 16.6%, the oxygen content control accuracy is improved by 33%, the combustion stability is improved by 15.5%, and the gas consumption is reduced by 2.1%, fully achieving the triple goals of "low nitrogen emissions, high efficiency and energy saving, and stable combustion" of this invention.

[0097] Example 2 is an example of low-NOx combustion control in a 1.2 million kcal gas-fired organic heat carrier heater in a chemical plant.

[0098] This embodiment applies to a 1.2 million kcal natural gas organic heat carrier heater in a chemical plant. The equipment needs to operate continuously for 24 hours, with production load fluctuations within ±15%. The original system used a dynamic air-fuel ratio adjustment mode, which had limitations. The problems of easy emission exceeding standards, large fluctuations in CO concentration, high fuel consumption, and high equipment failure rate can be addressed by using the system and method of this invention to complete 30 days of continuous industrial operation verification.

[0099] 1. System hardware and baseline parameter configuration

[0100] Flue gas detection device: The configuration is the same as in Example 1. In view of the high temperature, high dust and strong electromagnetic interference in the chemical plant, a dustproof filter module at the sampling end and an anti-interference shielding layer for signal transmission are added to ensure the stability and accuracy of data acquisition.

[0101] Combustion controller: The core parameters are preset as follows:

[0102] The fixed ratio of natural gas to air is 1:12, corresponding to an initial air volume of 1395 Nm³ / h. The air volume can be adjusted within ±10% of the initial value.

[0103] The initial opening of the smoke return regulating valve is 40%, and the upper and lower adjustment range is ±10% of the initial value;

[0104] The rigid limit for CO is 20 mg / m³, and the baseline oxygen content is... =3%VOL, The threshold for compliance is ≤50mg / m³;

[0105] It presets fixed air-fuel ratio benchmarks for three load levels: 50%, 75%, and 100%, to adapt to load fluctuations.

[0106] Actuator: Same configuration as in Example 1, valve diameter adapted to high flow conditions, adjustment step set to 2%-5% to avoid sudden changes in combustion parameters under large load fluctuations.

[0107] 2. Control process optimization and execution

[0108] The core control steps in this embodiment are completely consistent with those in Embodiment 1. However, considering the characteristics of continuous production and large load fluctuations in chemical plants, the following aspects are optimized:

[0109] Load adaptive benchmark matching: The combustion controller collects the heating furnace heat load signal in real time and automatically matches the fixed air-fuel ratio benchmark value under the corresponding load to ensure the basic stability of combustion under variable load conditions;

[0110] Rigid constraint priority locking: CO concentration is checked first throughout the process. If CO approaches the 20 mg / m³ threshold due to load fluctuations, the process is immediately suspended. In terms of regulation, priority should be given to adjusting the air volume and flue gas volume to ensure complete combustion. Once the CO concentration stabilizes at ≤18mg / m³, the original levels can be restored. Coordinated regulation;

[0111] Stable and coordinated adjustment: For load fluctuations, all fine-tuning adopts a step size of 1%-3%, and the adjustment range of air volume and smoke return volume in a single instance does not exceed 5%, so as to avoid combustion instability caused by sudden parameter changes.

[0112] 3. Implementation Results and Numerical Verification

[0113] This embodiment involves 30 consecutive days of industrial operation, completing the full-cycle operation data collection. Numerical calculations, the core effects are as follows:

[0114] 1. Emissions and combustion stability: The CO concentration remained stable at 10-18 mg / m³ throughout the entire process, with no instances of exceeding the standard; The calculated value is consistently ≤35mg / m³, meeting the stringent local environmental protection requirements; the oxygen content control accuracy is consistently within ±1%VOL, without significant fluctuations.

[0115] 2. Energy-saving benefits: Compared with the traditional dynamic air-fuel ratio control method before the renovation, the thermal efficiency of the heating furnace is increased by 15% and the natural gas fuel consumption is reduced by 28%, which is fully consistent with the energy-saving effect of this invention.

[0116] 3. Equipment reliability: During continuous operation, the failure rate of the burner and supporting equipment is reduced by 30% compared with before the modification. There are no equipment overheating, carbon buildup, or flameout failures caused by unstable combustion, which greatly reduces equipment operation and maintenance costs and is suitable for the continuous production conditions of chemical plants.

[0117] Example 3: Low-NOx Combustion Control in 800,000 kcal Ceramic Tunnel Kilns in the Building Materials Industry

[0118] This embodiment applies to an 800,000 kcal natural gas burner in a ceramic tunnel kiln at a building materials factory. The equipment operates intermittently under variable load, with production load fluctuating between 50% and 100%. The original control method could not simultaneously ensure combustion stability under low load and low NOx emissions across all operating conditions, resulting in flameout at low load and NOx emissions at high load. x The problems of exceeding standards and high energy consumption can be addressed by using the system and method of this invention to modify the system and complete continuous operation verification.

[0119] 1. System hardware and baseline parameter configuration

[0120] Flue gas detection device: The configuration is the same as in Example 1. Considering the characteristics of tunnel kilns with multiple burners and long flues, three distributed acquisition units are set at the flue outlet. The average value is taken as the calculation basis to ensure the representativeness and accuracy of flue gas parameter acquisition.

[0121] Combustion controller: The core parameters are preset as follows:

[0122] The fixed ratio of natural gas to air is 1:11, corresponding to an initial air volume of 930 Nm³ / h. The air volume can be adjusted within ±10% of the initial value.

[0123] The initial opening of the smoke return regulating valve is 35%, and the upper and lower adjustment range of the opening is ±10% of the initial value.

[0124] The rigid limit for CO is 20 mg / m³, and the baseline oxygen content is... =3%VOL, The threshold for compliance is ≤50mg / m³;

[0125] It presets fixed air-fuel ratio benchmarks for three load levels: 50%, 75%, and 100%, to achieve stable adaptation across the entire load range.

[0126] Actuator: Same configuration as in Example 1. In view of the characteristics of the 6 sets of burners in the tunnel kiln, a multi-channel synchronous drive module is set to ensure the consistency of coordinated adjustment of multiple burners.

[0127] 2. Control process optimization and execution

[0128] The core control steps in this embodiment are completely consistent with those in Embodiment 1. However, considering the intermittent variable load operating conditions of the tunnel kiln, the following aspects are optimized:

[0129] Disturbance-free load switching control: When the tunnel kiln switches between increasing and decreasing load, the combustion controller automatically matches the fixed air-fuel ratio reference of the corresponding load and synchronously adjusts the adjustment range of air volume and flue gas volume to achieve disturbance-free adjustment during the load switching process and avoid combustion fluctuations;

[0130] Low-load stable combustion priority control: When the load is below 60%, the combustion controller prioritizes the stability of the air volume under the rigid constraint of CO≤20mg / m³, and only achieves this through fine-tuning of the back smoke volume. Adjustments are made to avoid the risk of engine shutdown due to reduced air volume under low load.

[0131] Full-condition closed-loop optimization: The combustion controller completes a full parameter verification every 100ms, synchronously adapting to load changes and flue gas parameter changes, and completing NO... x Real-time numerical calculation and dynamic optimization of the fine-tuning range ensure that the air volume and smoke return volume are always within the preset ±10% range under all operating conditions.

[0132] 3. Implementation Results and Numerical Verification

[0133] This embodiment undergoes continuous operation verification, completing the full-condition data collection. Numerical calculations, the core effects are as follows:

[0134] Full-condition emission compliance: CO concentration ≤20mg / m³ throughout the 50%-100% full load range, ensuring complete combustion; The calculated value was ≤48mg / m³ throughout the entire process, with no instances of exceeding the standard, thus meeting the environmental emission requirements for the building materials industry.

[0135] Improved combustion stability: No flameout or flameout failures under low load conditions, with combustion stability fluctuation value ≤1.5%, completely solving the problem of difficult stable combustion under low load in the original control method;

[0136] Overall benefits: Compared with traditional control methods, tunnel kilns reduce overall fuel consumption by 16% and extend the maintenance cycle of burners and supporting equipment by 30%, combining environmental and economic benefits and adapting to the complex operating conditions of industrial kilns.

[0137] It should be noted that, in this document, the terms "comprising," "including," and any other variations are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Specific examples have been used in this document to illustrate the principles and implementation methods of the present invention. These examples are merely for the purpose of helping to understand the method and core ideas of the present invention. The above descriptions are only preferred embodiments of the present invention. It should be pointed out that, due to the limitations of written expression and the objective existence of infinite specific structures, those skilled in the art can make several improvements, modifications, or variations without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, variations, or combinations, or the direct application of the concept and technical solution of the present invention to other situations without modification, should all be considered within the scope of protection of the present invention.

Claims

1. A reverse intelligent control burner based on flue gas composition analysis, characterized in that, This includes a flue gas detection device, a combustion controller, and an actuator that are linked by signals in sequence to form a closed-loop control circuit; The flue gas detection device is used to collect parameters of carbon monoxide, nitrogen monoxide and oxygen content in the flue gas of the burner in real time, and transmit the collected parameters to the combustion controller. The combustion controller is preset with a fixed ratio of gas to air, an air volume adjustment range corresponding to the initial air volume, an opening adjustment range corresponding to the initial opening of the back smoke regulating valve, and a rigid constraint value of 20 mg / m³ for carbon monoxide content. Within the limit of the rigid carbon monoxide constraint value, the combustion controller obtains the real-time concentration of nitrogen oxides based on the received flue gas parameters, generates a coordinated fine-tuning command for air volume and flue gas return volume, and regulates nitrogen oxide emissions by reducing air volume and increasing flue gas return volume. The actuator receives the coordinated fine-tuning command and drives the air valve and the smoke return regulating valve to perform corresponding opening adjustments.

2. The intelligent reverse control burner based on flue gas composition analysis according to claim 1, characterized in that, The flue gas detection device adopts a composite detection scheme that combines non-dispersive infrared technology with electrochemical sensing. Non-dispersive infrared technology is used to detect carbon monoxide, while electrochemical sensors are used to detect nitric oxide and oxygen content.

3. The intelligent reverse control burner based on flue gas composition analysis according to claim 1, characterized in that, The combustion controller integrates a benchmark preset module, a data preprocessing module, a parameter calculation module, a concentration determination module, an instruction generation module, and a back smoke regulating valve control module, and has a built-in ARM processor and PLC control unit.

4. The intelligent reverse control burner based on flue gas composition analysis according to claim 1, characterized in that, The air volume adjustment range is an upward and downward adjustment range based on the initial air volume value, and the smoke return regulating valve opening adjustment range is an upward and downward adjustment range based on the initial opening. The single-item single fine adjustment range of both is uniformly 10%, and there is a rigid constraint value of 20 mg / m³ carbon monoxide content and an oxygen reference value set at the same time.

5. A reverse intelligent control burner based on flue gas composition analysis according to claim 4, characterized in that, The parameter calculation module calculates the nitrogen oxide concentration and reference oxygen conversion value using a preset formula. The calculation formula is as follows: ； Where NO represents the measured concentration of nitric oxide. To preset the oxygen reference value, This is the measured value of oxygen content.

6. The intelligent reverse control burner based on flue gas composition analysis according to claim 1, characterized in that, The combustion controller, based on the premise that the measured carbon monoxide value is ≤20mg / m³ and the fuel is fully combusted, generates corresponding adjustment commands according to the nitrogen oxide concentration to adjust the air volume and the opening of the smoke return regulating valve.

7. A reverse intelligent control burner based on flue gas composition analysis according to claim 1, characterized in that, The actuators include a servo motor driver, an air valve actuator, and a smoke return regulating valve actuator.

8. A control method for a flue gas composition analysis-based reverse intelligent control burner, based on the flue gas composition analysis-based reverse intelligent control burner according to any one of claims 1-7, characterized in that, Includes the following steps: S1 Preset: Presets a fixed ratio of gas to air, an air volume adjustment range corresponding to the initial air volume, an opening adjustment range corresponding to the initial opening of the back smoke regulating valve, a rigid constraint value of 20 mg / m³ for carbon monoxide content, and simultaneously sets an oxygen reference value. S2 Data Acquisition: Real-time acquisition of parameters such as carbon monoxide, nitrogen monoxide, and oxygen content in the flue gas during burner operation; S3 Rigid Constraint Judgment: Compare the measured carbon monoxide value with the rigid constraint value of 20 mg / m³. If the measured value exceeds the standard, adjust the air volume and smoke return volume to meet the standard before proceeding to the next step. S4 Nitrogen Oxide Concentration Determination: Based on the collected flue gas parameters, the real-time nitrogen oxide concentration is obtained, and the direction and magnitude of the fine adjustment of the air volume and the return smoke regulating valve are determined. S5 Coordinated Regulation Execution: Under the premise that the carbon monoxide content does not exceed 20 mg / m³, a coordinated fine-tuning instruction is generated based on the judgment result, and nitrogen oxide emissions are controlled by reducing the air volume and increasing the amount of smoke returned. S6 closed-loop feedback optimization: continuously monitors flue gas parameters and valve opening, feeds back the adjustment results in real time, dynamically optimizes the fine-tuning range, and maintains stable system operation.

9. The control method for a reverse intelligent control burner based on flue gas composition analysis according to claim 8, characterized in that, The flue gas detection device in S2 continuously collects the flue gas generated during the burner operation at a frequency of 20 times per second, and simultaneously acquires three core parameters: nitric oxide, carbon monoxide, and oxygen content, and transmits them to the combustion controller in a timely manner.

10. The control method for a reverse intelligent control burner based on flue gas composition analysis according to claim 8, characterized in that, S5 executes the following instruction logic based on the nitrogen oxide concentration. The specific instruction logic is as follows: If the nitrogen oxide concentration is higher than the preset threshold, the air volume will be reduced within the adjustment range of the initial air volume value, with the reduction not exceeding 10%. At the same time, the valve opening of the smoke return regulating valve will be increased within the adjustment range, with the increase not exceeding 10%. If the nitrogen oxide concentration is within the preset acceptable range, reduce the air volume within the air volume adjustment range, with the reduction not exceeding 3%, while simultaneously maintaining a stable opening of the smoke return regulating valve; If the nitrogen oxide concentration is lower than the lower limit of the preset compliance range, maintain the initial value of the air volume and the initial opening of the smoke return regulating valve unchanged.

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