Natural gas-hydrogen dual-fuel low-nitrogen combustion self-adaptive regulation and control system

Abstract

The invention discloses a natural gas-hydrogen dual-fuel low-nitrogen combustion self-adaptive regulation and control system, and relates to the technical field of proportional mixed combustion systems. The system comprises a control unit, a combustion characteristic detection unit, a self-adaptive regulation and control unit, a fuel supply unit, a three-stage turbulent burner unit and a carbon capture and resource utilization unit. The combustion characteristic detection unit collects flame speed, concentration and boiler load data in real time, the self-adaptive regulation and control unit is coupled with the data to calculate the optimal hydrogen mixing proportion, the fuel supply unit accurately mixes fuel according to instructions, and the three-stage turbulent burner unit achieves low-nitrogen stable combustion. And the carbon capture and resource utilization unit supplies low-carbon hydrogen and cyclically produces methanol. The system can adapt to fuel mixing and load fluctuation, solves the problems of unstable combustion, standard exceeding, high catalyst cost, incomplete carbon emission reduction and the like, and realizes low-carbon and low-nitrogen operation of the industrial boiler.

Description

Technical Field

[0001] This invention relates to the field of proportional mixing combustion system technology, specifically to a natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system. Background Technology

[0002] As the global energy structure transitions towards a green and low-carbon model, carbon reduction and nitrogen oxide reduction have become key development directions for industrial boilers, which are high-energy-consuming and high-emission equipment. Natural gas, as a clean fossil fuel, is widely used in industrial boiler combustion, but the combustion of natural gas alone still suffers from high nitrogen oxide emissions and limited carbon reduction potential. Hydrogen, as a zero-carbon fuel, produces only water during combustion with no carbon emissions. Blending hydrogen with natural gas can effectively reduce carbon emissions from the combustion system while improving combustion characteristics. Therefore, natural gas-hydrogen dual-fuel combustion technology has become the preferred path for low-carbon retrofitting of industrial boilers.

[0003] Currently, the industrial application of natural gas-hydrogen dual-fuel combustion technology still faces many key technological bottlenecks, hindering its large-scale promotion. Firstly, the combustion characteristics of hydrogen and natural gas differ significantly. Hydrogen has a low ignition point, fast flame propagation speed, and high combustion intensity, while natural gas has good combustion stability but… The generation rate is high. When the hydrogen blending ratio fluctuates within the range of 0-30% by volume, and the industrial boiler load fluctuates by ±20%, unstable combustion and backfire are likely to occur. Problems such as excessive emissions exist because existing combustion systems lack precise adaptive control capabilities and cannot dynamically match fuel blending ratios with load changes.

[0004] Secondly, most existing dual-fuel burners are modified from traditional single-fuel burners and do not employ a targeted staged and zoned structural design. This makes it impossible to achieve stable and coordinated combustion of hydrogen and natural gas, and it is difficult to suppress combustion through optimizing the combustion space distribution. Meanwhile, in order to improve combustion efficiency and reduce ignition temperature, existing technologies mostly use precious metal catalysts such as platinum and rhodium or metal oxide catalysts such as iron and cerium. These metal catalysts are not only energy-intensive and expensive to mine, but also easily contaminated by carbon deposits and have reduced activity under long-term high-temperature combustion conditions, requiring frequent replacement, which increases the system operation and maintenance costs and contradicts the demand for low-carbon and low-cost industrial transformation.

[0005] Furthermore, the hydrogen supply of natural gas-hydrogen dual-fuel combustion systems largely relies on traditional hydrogen production processes. These processes generate a large amount of carbon dioxide tail gas, which, if directly emitted, would negate the carbon reduction effect of hydrogen co-combustion, making it impossible to achieve a closed loop of hydrogen production, combustion, and carbon emission reduction. Existing carbon capture technologies are mostly deployed independently, with poor coordination with combustion and hydrogen production systems, high capture energy consumption, and a lack of effective resource utilization pathways for captured carbon dioxide, making it difficult to form a complete low-carbon closed-loop system.

[0006] Furthermore, existing natural gas-hydrogen dual-fuel combustion systems primarily operate independently, lacking a unified control unit for coordinated operation. This prevents the formation of a real-time closed loop encompassing detection, control, fuel supply, combustion, and re-detection, resulting in low system efficiency, delayed control, and difficulty in simultaneously ensuring combustion stability and low emissions. Emissions and low-carbon targets.

[0007] To address the shortcomings of existing technologies, there is an urgent need to develop a system capable of adaptive control of wide-ratio blending of natural gas and hydrogen, stable low-NOx combustion, and a closed-loop system for carbon capture and resource utilization, thus resolving the combustion instability issues in existing technologies. Addressing issues such as excessive emissions, high catalyst costs, incomplete carbon reduction, and poor system synergy, this solution adapts to the actual operational needs of industrial boilers, promoting the low-carbon and zero-carbon transformation of the industrial boiler industry. Summary of the Invention

[0008] To address the technical problems existing in the prior art, this application provides a natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system.

[0009] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0010] A natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system, characterized in that it includes:

[0011] Control unit;

[0012] The combustion characteristic detection unit is used to measure flame velocity, nitrogen oxide concentration and boiler load in real time, and transmit the data to the control unit.

[0013] An adaptive control unit is used to obtain the optimal hydrogen blending ratio based on the detection data;

[0014] The fuel supply unit is used to receive instructions from the adaptive control unit and precisely mix natural gas and low-carbon hydrogen from the hydrogen production unit according to the instructions, and then deliver them to the burner.

[0015] The three-stage swirl burner unit is used to burn mixed fuels. The waste heat generated is transferred to the carbon capture unit, and the flue gas is then transferred to the detection unit.

[0016] The carbon capture and resource utilization unit is used to supply low-carbon hydrogen to the fuel supply unit, and the captured carbon dioxide is recycled to produce methanol.

[0017] Furthermore, the combustion characteristic detection unit includes a flame speed detection module for acquiring flame speed, a nitrogen oxide concentration detection module for acquiring nitrogen oxide concentration, and a boiler load detection module for acquiring boiler load. The flame speed detection module, the nitrogen oxide concentration detection module, and the boiler load detection module are all connected to the control unit, and the acquired data is transmitted to the control unit in real time after signal processing.

[0018] Furthermore, the adaptive control unit has a built-in fuel combustion characteristic database, which is coupled with the detection data for calculation, and is used to dynamically and adaptively adjust the hydrogen blending ratio to adapt to boiler load fluctuation conditions.

[0019] Furthermore, the fuel supply unit includes a mixing module and a flow regulation module. The flow regulation module adjusts the delivery flow rates of natural gas and low-carbon hydrogen according to the instructions of the adaptive control unit to ensure that the mixing ratio meets the control requirements. The mixing module is used to achieve uniform mixing of the two fuels.

[0020] Furthermore, the three-stage swirl burner unit adopts a graded and zoned structure, including a central hydrogen enrichment zone and a peripheral natural gas zone, to achieve coordinated and stable combustion of natural gas and low-carbon hydrogen, while suppressing the generation of nitrogen oxides by shortening the flame length;

[0021] The three-stage swirl burner unit is equipped with a metal-free catalyst layer, which is loaded with a nitrogen-doped nano-carbon metal-free catalyst to assist in the complete combustion of the mixed fuel, reduce the ignition temperature, and further suppress the generation of nitrogen oxides. The nitrogen-doped nano-carbon metal-free catalyst uses graphene or carbon nanotubes as the substrate and is modified by multi-element co-doping and / or defect engineering.

[0022] Furthermore, multi-element co-doping modification involves introducing one or more non-metallic elements from boron, sulfur, and fluorine to form a co-doped structure based on nitrogen doping and phosphorus doping. The molar ratio of nitrogen to phosphorus is controlled at (3:1)-(5:1). The co-doped elements regulate the electronic structure of nano-carbon and increase active sites.

[0023] Furthermore, the defect engineering modification employs one or more of the following methods: plasma etching, ball milling, strong acid oxidation, or high-temperature annealing, to create edge defects or vacancy defects on the surface of nitrogen-doped carbon nanomaterials, thereby increasing the number of edge active sites and inhibiting carbon deposition on the catalyst surface.

[0024] Furthermore, the metal-free catalyst layer is disposed on the inner wall of the combustion chamber and the surface of the microscale structure of the three-stage swirl burner unit; the nitrogen-doped nano-carbon metal-free catalyst can be prepared using the byproducts of the carbon capture unit.

[0025] Furthermore, the carbon capture and resource utilization unit includes a hydrogen production module, a carbon capture module, and a resource utilization module. The hydrogen production module is used to produce low-carbon hydrogen, the carbon capture module is used to capture carbon dioxide, and the resource utilization module couples the captured carbon dioxide with green hydrogen to synthesize methanol.

[0026] Furthermore, the control unit has functions of data reception, command issuance, linkage coordination, and fault early warning.

[0027] Beneficial effects:

[0028] 1. This system uses a combustion characteristic detection unit to collect real-time data on flame velocity, Based on concentration and boiler load data, the adaptive control unit, relying on its built-in fuel combustion characteristic database, dynamically calculates the optimal hydrogen blending ratio by coupling detection data. It can accurately adapt to hydrogen blending fluctuations of 0-30% by volume, while also handling boiler load fluctuations of ±20%, ensuring the mixed fuel remains in a stable combustion state and preventing backfire and flameout. Combined with the graded and zoned structure of the three-stage swirl burner, it shortens the flame length and optimizes the combustion space distribution, suppressing flame spread at its source. It generates a dual guarantee of low nitrogen emission effect, meeting the environmental emission requirements of industrial boilers.

[0029] 2. This system incorporates a metal-free catalytic layer within a three-stage swirl burner, supporting a nitrogen-doped nano-carbon catalyst modified by multi-element co-doping and / or defect engineering. Using graphene or carbon nanotubes as the substrate, it eliminates the need for any metal components, completely resolving the drawbacks of traditional precious metal and metal oxide catalysts, such as high cost, high energy consumption during mining, and easy carbon deposition and failure. Multi-element co-doping modification can regulate the electronic structure of nano-carbon and increase active sites, while defect engineering modification can inhibit carbon deposition and extend catalyst lifespan. These two processes synergistically enhance catalytic activity, effectively reducing the ignition temperature of the mixed fuel and promoting complete combustion, further improving the low-NOx effect and combustion efficiency. Simultaneously, the catalyst can be prepared using byproducts from the carbon capture unit, further implementing the low-carbon concept and reducing preparation costs. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a block diagram illustrating the structural principle of the natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to the first embodiment of the present invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Example

[0034] Please refer to Figure 1 This embodiment provides a natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system, including:

[0035] The control unit receives three types of raw detection data—flame velocity, nitrogen oxide concentration, and boiler load—from the combustion characteristic detection unit in real time. It filters, calibrates, and normalizes the data to eliminate detection errors and converts it into a standardized data format recognizable by the adaptive control unit, preventing control decision errors caused by raw data deviations. The processed standardized data is synchronously transmitted to the adaptive control unit as the core basis for blending ratio calculation. Simultaneously, it receives the optimal hydrogen blending ratio control command output by the adaptive control unit and forwards it to the fuel supply unit without delay, clarifying the quantitative requirements for fuel blending. It monitors the operating status of the fuel supply unit, the three-stage swirl burner unit, and the carbon capture and resource utilization unit in real time. If any unit experiences an operational anomaly, it immediately issues an emergency control command to ensure the overall safe and stable operation of the system. It records the detection data, control commands, and unit operating parameters throughout the entire process, forming an operating log to provide data support for subsequent parameter optimization and fault diagnosis.

[0036] The combustion characteristic detection unit is used to measure flame velocity, nitrogen oxide concentration and boiler load in real time and transmit the data to the control unit. It provides real, dynamic and multi-dimensional operating conditions and combustion data for adaptive regulation. It is the data foundation for the system to achieve adaptive regulation. Without accurate detection, there is no effective regulation decision.

[0037] Specifically, this unit integrates a flame velocity sensor, The system comprises three core detection components: an online concentration analyzer, a boiler load transmitter, and others. Each component performs its specific detection function, and the data is then fused and transmitted uniformly. Specifically, a flame velocity sensor is deployed in the flame combustion zone of the three-stage swirl burner to capture the flame propagation velocity of the natural gas-hydrogen mixed fuel in real time. The core detection purpose is to determine combustion stability; a higher hydrogen blending ratio results in a faster flame propagation velocity, but an excessively high ratio can easily lead to backfire and deflagration. This data serves as a safety threshold constraint indicator for the blending ratio. The online concentration analyzer is deployed at the flue gas outlet of the three-stage swirl burner to sample and analyze the exhaust gas after combustion in real time, accurately obtaining the concentration of [unclear - possibly related to concentration in the flue gas]. The concentration value is used to determine the effectiveness of low-NOx combustion, and this data serves as a constraint indicator for the emission reduction target of the blending ratio. A boiler load transmitter is deployed at the boiler's heat output end to monitor the actual heat output power in real time. Its core purpose is to determine the total fuel supply demand. The boiler load dynamically changes with industrial heat or power generation demand; a higher load corresponds to a larger total fuel supply. This data is a fundamental indicator of the blending ratio's operating conditions. The real-time data from these three types of detection components are integrated and transmitted to the control unit at a preset transmission frequency to ensure synchronization between the detection data and actual combustion conditions, avoiding control lag due to data transmission delays. Downstream, it provides fixed-point detection for the flame zone and flue gas end of the three-stage swirl burner unit; upstream, it transmits raw detection data to the control unit for the system to sense changes in combustion conditions.

[0038] The adaptive control unit is used to obtain the optimal hydrogen blending ratio based on detection data. This intelligent calculation of the optimal hydrogen blending ratio based on detection data is the technology behind the system's adaptive control and a key feature distinguishing it from traditional fixed-ratio dual-fuel combustion systems. This unit incorporates a multi-dimensional coupled optimization algorithm model, using load matching, low-NOx compliance, and combustion stability as multiple optimization objectives to dynamically calculate the blending ratio. Specifically, it receives standardized flame velocity from the control unit... Concentration and boiler load data, and retrieve preset thresholds from the built-in model;

[0039] It should be noted that the preset thresholds are set as follows:

[0040] Concentration threshold is The upper limit of emission concentration serves as the basis for determining whether current combustion meets low-NOx standards, and is monitored in real time. Concentration < preset threshold:

[0041] The combustion low-NOx effect meets the requirements, and the hydrogen blending ratio can be maintained or finely adjusted within a safe range;

[0042] Real-time detection Concentration ≥ preset threshold:

[0043] The system was determined to have exceeded emission standards, and the current core optimization goal is to enhance the low-nitrogen effect.

[0044] Provided the flame velocity does not exceed the limit, increasing the hydrogen blending ratio utilizes the low combustion temperature and rapid flame propagation characteristics of hydrogen to suppress [flame damage]. generate.

[0045] For natural gas-hydrogen blended fuels, the upper limit of flame propagation speed is determined through combustion tests and simulations. This upper limit corresponds to the critical safety value to avoid backfire, flameout, deflagration, and thermal damage to the burner, which is the flame speed threshold.

[0046] When the real-time flame velocity is less than the preset safety threshold:

[0047] The combustion state is stable, and there is still room to increase the hydrogen blending ratio.

[0048] When the real-time flame velocity is greater than or equal to the preset safety threshold:

[0049] If the system is determined to be approaching or entering a dangerous operating condition, its current core objective is to ensure combustion safety by immediately reducing the hydrogen blending ratio, slowing down the flame propagation speed, and preventing safety accidents such as backfire and deflagration.

[0050] The boiler load threshold is a pre-set allowable range of boiler load fluctuations, including: load mutation threshold, minimum stable load threshold, and rated load upper limit threshold.

[0051] Triple target threshold determination:

[0052] First, threshold comparisons are performed on the detection data to identify the core issues in the current operating condition:

[0053] like To improve emission reduction, the hydrogen blending ratio needs to be increased within the safe range of flame velocity, as the concentration exceeds the standard.

[0054] If the flame velocity approaches the safety threshold, and the core objective is to ensure stable combustion, the hydrogen blending ratio must be immediately reduced to avoid safety accidents. If the boiler load changes abruptly, the core objective is to match the load demand; first, adjust the total fuel supply, and then adapt the corresponding hydrogen blending ratio. Based on the ternary correlation model, the boiler load is used as the fundamental variable. With concentration as an emission reduction constraint variable and flame speed as a safety constraint variable, the optimal hydrogen blending ratio is calculated through algorithm iteration to simultaneously satisfy load matching, low nitrogen compliance, and stable combustion. The calculated optimal hydrogen blending ratio is then converted into a quantitative control command and transmitted to the control unit as the basis for fuel supply unit allocation.

[0055] It receives standardized detection data from the control unit and outputs quantitative control commands to the control unit to connect the sensing data with the execution action.

[0056] The fuel supply unit receives instructions from the adaptive control unit and precisely mixes natural gas and low-carbon hydrogen from the hydrogen production unit according to the instructions, then delivers it to the burner. Precisely mixing and quantitatively delivering natural gas and low-carbon hydrogen according to the control instructions is the core of implementing adaptive control decisions. Without precise fuel mixing, the results of adaptive control cannot be realized.

[0057] Specifically, the aforementioned unit integrates four types of components: a natural gas flow regulating valve, a hydrogen flow regulating valve, a high-precision mixing chamber, and a fuel delivery pump. Its working objectives are precise proportioning, uniform mixing, and stable delivery. Specifically, it receives instructions and analyzes parameters: it receives hydrogen blending ratio control instructions from the control unit and, in conjunction with boiler load data, calculates the total fuel supply and clarifies the individual supply flow rates of natural gas and hydrogen.

[0058] The natural gas flow regulating valve and the hydrogen flow regulating valve are used to precisely regulate the flow of natural gas from the natural gas pipeline network and low-carbon hydrogen from the carbon capture and resource utilization unit, respectively. The regulation accuracy of the regulating valve is matched with the calculation accuracy of the adaptive control unit to ensure that the error of the blending ratio is within the allowable range.

[0059] The regulated natural gas and hydrogen are introduced into a high-precision mixing chamber. Through a turbulence structure within the chamber, the two fuels are thoroughly mixed to form a homogeneous natural gas-hydrogen mixture. This prevents uneven mixing from causing excessively high localized flame temperatures in the burner, thus avoiding localized combustion. Exceeding the standard;

[0060] The fuel delivery pump stably delivers the uniformly mixed fuel to the three-stage swirl burner unit according to the total supply, ensuring a continuous and stable fuel supply to the burner and laying the foundation for stable combustion.

[0061] The three-stage swirl burner unit is used to burn mixed fuels. The waste heat generated is transferred to the carbon capture unit, and the flue gas is then transferred to the detection unit. It is used to achieve efficient and low-NOx combustion of natural gas-hydrogen mixed fuels, while completing the directional transfer of combustion waste heat and the closed-loop return of flue gas, so as to achieve low-NOx combustion in the system.

[0062] This unit aims to achieve staged combustion, uniform mixing, and low-oxygen combustion, thereby ensuring complete combustion of the mixed fuel while further suppressing oxygen levels during the combustion process. Generation, simultaneously completing the directional transfer of energy and medium, specifically:

[0063] After the mixed fuel is delivered from the fuel supply unit to the burner, it is mixed with the combustion air through the burner's three-stage swirl channel. The three-stage swirl structure achieves staged air distribution and staged combustion.

[0064] This achieves initial mixing of fuel and air, forming a fuel-rich, low-oxygen combustion zone, reducing the temperature of the flame core, and suppressing thermal combustion. generate;

[0065] Supplementing with adequate air ensures complete combustion of fuel, improves combustion efficiency, and prevents energy waste caused by unburned fuel.

[0066] This creates a swirling flue gas recirculation, reducing the gradient of the overall flame temperature field, making the flame temperature distribution more uniform, and further reducing... The synergistic effect of the three-stage swirl, combined with the low-NOx effect of hydrogen blending, creates a dual emission reduction, significantly lowering emissions. Emission concentration.

[0067] Directional transfer of combustion waste heat: The high-temperature flue gas and heat energy generated by fuel combustion are transferred to the carbon capture and resource utilization unit through the waste heat exchange surface of the burner, providing heat energy for the carbon capture process, reducing the external energy consumption of the carbon capture unit, and improving the overall energy utilization rate of the system.

[0068] After waste heat transfer, the low-temperature flue gas is directionally returned to the combustion characteristic detection unit through a dedicated flue gas pipeline, where the detection unit collects data in real time from the flue gas. Concentration data forms a closed loop for combustion-flue gas detection, ensuring... The specificity and real-time nature of concentration detection;

[0069] The system transmits real-time operational status data, such as burner ignition status, flame stability, and flashback warning, to the control unit, providing a basis for emergency control of the system.

[0070] It receives mixed fuel from the fuel supply unit, transmits flue gas back to the combustion characteristic detection unit, transfers waste heat to the carbon capture and resource utilization unit, and feeds back the combustion status to the control unit, serving as the combustion core and energy / medium transfer hub of the system.

[0071] The carbon capture and recycling unit is used to supply low-carbon hydrogen to the fuel supply unit, and the captured carbon dioxide is used to produce methanol in a recycling process.

[0072] Used to provide the system with low-carbon hydrogen feedstock, achieving the goal of reducing hydrogen emissions from combustion flue gas. The efficient capture and resource utilization of hydrogen energy breaks the traditional dual-fuel combustion system model of direct carbon emissions and external hydrogen supply, which is the characteristic of the system to achieve low-carbon and circular operation.

[0073] This unit integrates a low-carbon hydrogen production module. Capture module The resource utilization module comprises three core modules that work collaboratively to achieve a closed loop of hydrogen energy supply, carbon capture, and carbon resource utilization. Specifically:

[0074] The low-carbon hydrogen production module is used to provide low-carbon hydrogen to the fuel supply unit. This module is the hydrogen energy supply source of the system. It produces hydrogen using a low-carbon hydrogen production process. The produced low-carbon hydrogen is directly transported to the fuel supply unit as a fuel feedstock for blending with natural gas, ensuring the overall low-carbon nature of dual-fuel combustion. At the same time, the hydrogen production rate is dynamically adjusted according to the hydrogen demand of the fuel supply unit to achieve a match between hydrogen energy supply and demand.

[0075] The capture module is used to efficiently capture gases from combustion flue gas. It receives the waste heat from the three-stage swirl burner unit and simultaneously processes the flue gas returned after combustion. High-efficiency capture: Through processes such as absorption, adsorption, and membrane separation, the gas containing... Separation and purification yield high-purity [product / material]. Gases, enabling source control of carbon emissions; capture The flue gas is treated to meet emission standards, significantly reducing the total carbon emissions of the system.

[0076] The resource utilization module is used to... The high-purity methanol collected will be converted into methanol chemical raw materials. ,pass The hydrogenation synthesis of methanol process is recycled, transforming industrial carbon emissions into high-value-added methanol chemical feedstock, achieving... This process transforms waste into treasure; methanol can be exported as an industrial raw material, enhancing the economic value of the system. Meanwhile, the byproducts of this process can be recycled into the hydrogen production module, further improving resource utilization.

[0077] It receives waste heat from the three-stage swirl burner unit and supplies low-carbon hydrogen to the fuel supply unit, while simultaneously completing the combustion of the flue gas. The capture and resource utilization of carbon, together with the fuel supply unit and the burner unit, form a low-carbon cycle of hydrogen energy supply, fuel combustion, carbon capture and carbon resource utilization.

[0078] It should be noted that when natural gas is mixed with its own generated hydrogen for combustion, the ignition temperature is lower and combustion is more complete without the action of a metal catalyst, resulting in a significant improvement in energy conversion rate. The heat and electricity released by combustion can be utilized in a cascade manner—prioritizing the needs of the main load, while the remaining medium- and low-temperature waste heat can be directly used for hydrogen production and the production of methanol from CO2 and hydrogen. The surplus electricity supplements the electricity required for the process, completely covering the energy consumption of both processes, with no energy inversion. At the same time, the produced methanol can be reused as auxiliary fuel for combustion, supplementing the system's energy and forming an energy cycle; moreover, the mixed combustion reduces the energy consumption of tail gas treatment, further optimizing the energy balance, achieving both NOx and CO2 emission reduction while ensuring reasonable energy consumption.

[0079] Furthermore, the combustion characteristic detection unit includes a flame velocity detection module for acquiring flame velocity, a nitrogen oxide concentration detection module for acquiring nitrogen oxide concentration, and a boiler load detection module for acquiring boiler load. The flame velocity detection module, nitrogen oxide concentration detection module, and boiler load detection module are all connected to the control unit, and the acquired data is transmitted to the control unit in real time after signal processing.

[0080] The combustion characteristic detection unit, as the front-end sensing unit of the system, is used to convert the physical conditions and pollutant emission indicators in the dual-fuel combustion process into electrical signals. After signal processing such as noise reduction, calibration, and normalization, detection errors and signal interference are eliminated, and then the signals are transmitted to the control unit in real time through the communication link, providing a unique and accurate data basis for subsequent hydrogen blending ratio calculation and combustion condition control.

[0081] Specifically, the working principle of the above-mentioned noise reduction signal processing is as follows: For mechanical interference caused by vibration of the combustion equipment and electromagnetic interference caused by electromagnetic radiation from the detection link, a passive suppression method is used to achieve interference isolation. On the one hand, a copper shield is added to the outside of the detection sensor probe and signal transmission line. Utilizing the electromagnetic induction shielding principle of metal shielding, the coupling interference of external electromagnetic radiation to the electrical signal is blocked. At the same time, the shield is reliably grounded to guide the electromagnetic interference signal to the ground, preventing the interference signal from superimposing in the transmission line. On the other hand, anti-interference capacitors are added at both ends of the signal transmission line. Utilizing the characteristic of capacitors to block DC and pass AC, high-frequency interference signals caused by mechanical vibration are filtered out, reducing signal fluctuations.

[0082] The working principle of the calibration signal processing is as follows: For the systematic error of the detection unit, a standard reference is used for benchmark calibration, which is performed monthly. First, the detection sensor is placed in a standard operating environment, connected to the standard reference, and the theoretical electrical signal value corresponding to the standard reference is recorded. Second, the actual electrical signal value output by the detection unit is acquired, the deviation between the actual signal and the reference signal is calculated, and a deviation correction model is established. Finally, the correction coefficient is embedded in the signal processing module to correct the subsequently acquired electrical signals in real time, ensuring that the static detection error is ≤±2%.

[0083] For example, for a NOx concentration sensor, if a standard NOx gas with a concentration of 100 ppm is connected, and the output electrical signal of the detection unit is 0.4V, while the standard signal corresponds to 0.41V, then the correction coefficient k = 0.41 / 0.4 = 1.025. All subsequent detected electrical signals need to be multiplied by 1.025 for correction.

[0084] Normalization processing works by converting different types and magnitudes of detection electrical signals into standardized signals of the same magnitude and standard. This eliminates the differences in the magnitude of electrical signals corresponding to different detection indicators, making it easier for the control unit to receive, identify, calculate, and process them uniformly. This ensures the consistency and accuracy of subsequent hydrogen blending ratio calculations and combustion condition control, while also enabling the comparability of different detection signals.

[0085] First, the electrical signal range corresponding to each detection index must be clearly defined, that is, the minimum and maximum values ​​of each detection signal must be determined. For example, the detection range of the combustion temperature sensor is 500-1500℃, corresponding to an electrical signal range of 0.1-5V; the detection range of the NOx concentration sensor is 0-500ppm, corresponding to an electrical signal range of 0-3V. The magnitudes of the electrical signals of different detection indexes vary greatly and cannot be directly processed uniformly by the control unit.

[0086] A linear mapping formula is used to map the original electrical signals of each detection index to a unified target range. The calculation formula is: Y=(X- ) / ( -)×5, where Y is the normalized electrical signal and X is the original detection electrical signal. This is the minimum value of the electrical signal corresponding to the detection index. This is the maximum value of the electrical signal corresponding to the detection index.

[0087] This formula transforms raw electrical signals of different magnitudes into standardized signals of 0-5V, thus unifying the signal magnitude.

[0088] For example, the NOx concentration sensor detects an initial electrical signal of 1.5V (corresponding to X=1.5V). =0V, =3V), after normalization Y=(1.5-0) / (3-0)×5=2.5V; the combustion temperature sensor detected the original electrical signal as 2.55V (corresponding to X=2.55V, =0.1V, =5V), after normalization Y=(2.55-0.1) / (5-0.1)×5=2.5V. The two different types of signals have the same magnitude after normalization and can be uniformly identified and processed by the control unit.

[0089] During the normalization process, the accuracy of the signal is simultaneously verified to ensure that the normalization error is ≤±1%. For abnormal signals that are outside the detection range, the system automatically marks them as abnormal signals and does not perform normalization processing. At the same time, the abnormal signals are fed back to the control unit to avoid the abnormal signals affecting the subsequent control logic. This ensures the reliability and consistency of the normalized signal and ultimately provides a unique and accurate standardized data basis for subsequent hydrogen blending ratio calculation and combustion condition control.

[0090] The three sub-modules each have their own functions, corresponding to the three core dimensions of dual-fuel combustion: safety constraints, emission reduction targets, and basic operating conditions. The detection data are interconnected and indispensable. After unified processing, they form a complete combustion operating condition data system, avoiding the one-sidedness of detection by a single module that may lead to control decision errors. At the same time, all modules establish direct communication connections with the control unit to ensure the real-time and synchronous transmission of data, adapting to the dual-fuel combustion characteristics of dynamic changes in boiler load and instantaneous fluctuations in flame state.

[0091] All three modules are dedicated detection modules, each with built-in corresponding sensors and signal acquisition components. For specific detection targets of dual-fuel combustion, they adopt appropriate detection methods to complete data acquisition at preset precise detection points. The detection frequency and detection accuracy are matched to the system's adaptive control response requirements.

[0092] Specifically, the flame speed detection module is used to obtain the flame propagation speed of the natural gas-hydrogen mixed fuel in the three-stage swirl burner in real time, which serves as the core safety indicator for judging the stability of dual-fuel combustion and sets a safe upper limit threshold for the hydrogen blending ratio for the adaptive control unit.

[0093] Since the hydrogen blending ratio directly affects the flame propagation speed, the detection accuracy and response speed of this module need to be adapted to the dynamic adjustment characteristics of the hydrogen blending ratio to avoid safety accidents caused by detection lag.

[0094] Its specific workflow is as follows: The module has a built-in laser flame velocity sensor, and the sensor probe is deployed in the core combustion zone of the three-stage swirling burner to directly capture the physical signal of flame propagation speed; The built-in signal acquisition component converts the captured physical signal into a raw electrical signal, completing the initial conversion from physical quantity to electrical signal; The raw electrical signal is initially filtered to eliminate signal interference caused by high temperature of the burner, flue gas, and swirling airflow, retaining the effective flame velocity signal for subsequent unified signal processing.

[0095] The adaptive control unit provides a basis for combustion safety constraints. When the detected flame speed approaches or reaches the preset safety threshold, the adaptive control unit will immediately reduce the hydrogen blending ratio to prioritize combustion stability.

[0096] The nitrogen oxide concentration detection module is used to obtain the nitrogen oxide concentration in the flue gas after combustion of the three-stage swirl burner in real time. As the core emission reduction indicator for judging the effect of low nitrogen combustion, it is also the core emission reduction constraint for the adaptive control unit to adjust the hydrogen blending ratio.

[0097] because The generation of flue gas is directly related to the hydrogen blending ratio, combustion temperature field, and swirling combustion atmosphere. Furthermore, the flue gas is characterized by high temperature and dust content. Therefore, this module adopts an online, high-temperature resistant design. The concentration analyzer is designed to detect points that avoid high-temperature waste heat exchange areas, ensuring the authenticity of the test data.

[0098] The specific workflow involves the module's built-in ultraviolet absorption method. An online concentration analyzer and a flue gas sampling probe are used. The sampling probe is deployed at the flue gas outlet of the three-stage swirl burner to continuously sample the post-combustion flue gas online, avoiding the problems caused by residual heat transfer and flue gas mixing. Concentration distortion; the analyzer performs rapid detection on the collected flue gas samples, analyzing the concentration of [unspecified substances] in the flue gas using ultraviolet absorption spectroscopy. The content of the pollutant is measured, and the detection results are converted into raw electrical signals. Preliminary calibration processing is performed on the raw electrical signals to eliminate the influence of dust content and humidity changes in the flue gas on the detection results, ensuring... The accuracy of the concentration data awaits further unified signal processing.

[0099] Provides a basis for low-NOx emission reduction constraints for the adaptive control unit, when the detected When the concentration exceeds or approaches the emission standard threshold, the adaptive control unit will increase the hydrogen blending ratio within the safe range of flame speed to enhance the low-NOx combustion effect.

[0100] The boiler load detection module is used to obtain the actual heat output load of the boiler in real time. As a core operating condition indicator for judging the total fuel supply demand, it is the basis for the adaptive control unit to calculate the hydrogen blending ratio.

[0101] The boiler load changes dynamically with the actual demand for industrial heat and power generation. The load change directly determines the total fuel supply. This module uses a high-precision load transmitter to directly detect the physical parameters at the boiler's heat output end, avoiding errors from indirect detection.

[0102] The specific workflow is as follows: the module has a built-in pressure boiler load transmitter, which is deployed at the heat output end of the boiler. By detecting the boiler output steam pressure, flow rate and temperature, and combining the boiler thermal efficiency formula, the actual heat output load of the boiler is calculated in real time. The calculated physical quantity of boiler load is directly converted into a standard electrical signal. This signal is an industrial standard signal with strong anti-interference and can enter the subsequent unified signal processing stage without preliminary processing.

[0103] This provides the operating condition basis for the adaptive control unit, which will use boiler load as the basic variable, combined with flame velocity, The concentration data is used to calculate the optimal hydrogen blending ratio under different loads, and at the same time, it provides a basis for calculating the total fuel supply to the fuel supply unit.

[0104] After the three sub-modules complete independent detection and raw signal acquisition, the combustion characteristic detection unit will perform unified signal processing and then transmit the processed standardized data to the control unit through a dedicated communication link.

[0105] Furthermore, the adaptive control unit has a built-in fuel combustion characteristic database, which is coupled with the detection data for calculation to dynamically and adaptively adjust the hydrogen blending ratio to adapt to boiler load fluctuation conditions.

[0106] The unit's built-in fuel combustion characteristic database pre-stores core combustion characteristic parameters under different blending ratios of natural gas and hydrogen, as well as adaptation benchmark data for different boiler load ranges and blending ratios, providing theoretical references and threshold constraints for ratio calculations.

[0107] It receives standardized real-time detection data forwarded by the control unit, which accurately reflects the current combustion conditions and the actual load requirements of the boiler.

[0108] Real-time monitoring data is coupled and matched with baseline data in the database, and algorithms are applied, with boiler load as the core operating condition variable and flame velocity as the combustion safety constraint. With low nitrogen emission reduction as the constraint, the optimal hydrogen blending ratio can be quickly calculated under the current load conditions to simultaneously meet the requirements of stable combustion, low nitrogen emission standards, and load matching.

[0109] When boiler load fluctuates, or flame speed, When the concentration deviates from the preset threshold, the unit immediately re-completes the coupling calculation based on the new detection data, adjusts the hydrogen blending ratio command in real time and issues it, without manual intervention, so as to achieve accurate and dynamic adaptation of the blending ratio to the boiler load fluctuation conditions, and ensure the low nitrogen and stability of dual-fuel combustion under all operating conditions.

[0110] Furthermore, the fuel supply unit includes a mixing module and a flow regulation module. The flow regulation module adjusts the delivery flow of natural gas and low-carbon hydrogen according to the instructions of the adaptive control unit to ensure that the mixing ratio meets the control requirements. The mixing module is used to achieve uniform mixing of the two fuels.

[0111] In this embodiment, the fuel supply unit, as the core of the dual-fuel precise blending and delivery, works in concert with the flow regulation module and the mixing module to precisely regulate the flow of natural gas and low-carbon hydrogen according to the instructions of the adaptive control unit, ensuring uniform fuel mixing and providing the burner with a compliant and homogeneous fuel mixture. Specifically, the fuel supply unit receives the hydrogen blending ratio control instruction from the adaptive control unit, specifying the required flow ratio of natural gas and low-carbon hydrogen. Based on this instruction, the flow regulation module independently measures and dynamically adjusts the flow of natural gas from the natural gas pipeline and low-carbon hydrogen supplied by the carbon capture and resource utilization unit, precisely controlling the delivery flow of the two fuels to ensure a strict matching and control of their mixing ratio from the source. The regulated natural gas and low-carbon hydrogen are then delivered to the mixing module, where the turbulence and mixing structure within the module ensures thorough and uniform mixing of the two fuels, preventing uneven local proportions that could lead to flame instability or localized combustion issues. Issues such as exceeding standards; the mixing module will stably deliver a precisely proportioned and uniformly composed natural gas-hydrogen mixed fuel to the three-stage swirl burner unit, providing a compliant fuel source for its low-NOx combustion, and the flow regulation module can dynamically adjust according to the instructions of the adaptive control unit to adapt to changes in fuel ratio and total supply under boiler load fluctuations.

[0112] Furthermore, the three-stage swirl burner unit adopts a graded and zoned structure, including a central hydrogen enrichment zone and a peripheral natural gas zone, to achieve coordinated and stable combustion of natural gas and low-carbon hydrogen, while suppressing the generation of nitrogen oxides by shortening the flame length;

[0113] The three-stage swirl burner unit is equipped with a metal-free catalyst layer, which is loaded with a nitrogen-doped nano-carbon metal-free catalyst to assist in the complete combustion of the mixed fuel, reduce the ignition temperature, and further suppress the formation of nitrogen oxides. The nitrogen-doped nano-carbon metal-free catalyst uses graphene or carbon nanotubes as the substrate and is modified by multi-element co-doping and / or defect engineering.

[0114] In this embodiment, a hierarchical and partitioned structure of a central hydrogen enrichment zone and an outer natural gas zone is adopted to adapt to the different combustion characteristics of hydrogen and natural gas. Hydrogen is rapidly ignited in the central zone to form a stable fire core, providing a continuous ignition source for the outer natural gas and achieving stable combustion of dual fuels. At the same time, this structure can shorten the flame length, avoid excessive extension of the high-temperature zone of the flame, reduce the generation of thermal nitrogen oxides, and achieve low-NOx combustion at the structural level.

[0115] The metal-free catalyst layer inside the burner is loaded with a nitrogen-doped nano-carbon metal-free catalyst based on carbon nanotubes and modified by multi-element co-doping / defect engineering. This catalyst can reduce the ignition temperature of the mixed fuel, promote complete combustion of the fuel, and reduce fuel-type nitrogen oxides produced by incomplete combustion. At the same time, the catalyst layer can optimize the combustion reaction path and further suppress the generation of nitrogen oxides during combustion, forming a dual low-NOx effect with structural control of nitrogen oxides.

[0116] It should be noted that the combustible components in fuel react fully with oxygen to produce stable oxides or elements. The conversion form of nitrogen depends primarily on the oxidizing power of the combustion system, the reaction temperature, and the role of the catalyst, as follows: The main conversion form is nitrogen gas, and complete combustion of nitrogen gas is the most important and stable conversion product. When combustion is complete, with sufficient oxygen supply and uniform temperature distribution, intermediate nitrogen-containing products such as NH3 and HCN generated from the cracking of organic nitrogen in the fuel will preferentially undergo reduction reactions or redox coupling reactions under the action of a catalyst, ultimately converting into non-toxic and stable N2.

[0117] (1) The intermediate product NH3 can undergo selective oxidation reaction under the action of sufficient O2 and catalyst to generate N2 (4NH3+3O2→2N2+6H2O).

[0118] (2) In a fully combustible environment, the intermediate product HCN will first be oxidized to NCO, and then NCO will react with NH3, H, etc. to finally be converted into N2, thus avoiding the generation of NOx.

[0119] Under extreme conditions of complete combustion and excess oxygen, a very small amount of nitrogen will be deeply oxidized to produce NO3⁻. However, the content of this product is extremely low, and it will condense with the water vapor in the combustion exhaust and be discharged in the form of soluble salts. It will not cause air pollution and can be ignored.

[0120] The graded and zoned fuel supply, combined with the three-stage swirling flow field, allows for more thorough mixing of fuel and combustion air. This, along with the combustion-supporting effect of the catalytic layer, not only improves combustion efficiency but also makes the flame temperature field distribution more uniform, avoiding the formation of local high-temperature zones. This further consolidates the low-NOx combustion effect while ensuring combustion stability under boiler load fluctuations.

[0121] Furthermore, multi-element co-doping modification involves introducing one or more non-metallic elements from boron, sulfur, and fluorine to form a co-doped structure based on nitrogen doping and phosphorus doping. The molar ratio of nitrogen to phosphorus is controlled at (3:1)-(5:1). The co-doped elements regulate the electronic structure of nano-carbon and increase active sites.

[0122] In this embodiment, a co-doped structure with a specific ratio is formed by introducing non-metallic elements such as boron, sulfur, and fluorine on the basis of nitrogen and phosphorus doping. This regulates the electronic structure of nano-carbon and increases active sites, thereby enhancing the catalyst's effects on combustion, ignition point reduction, and nitrification suppression of mixed fuels. Specifically, using graphene / carbon nanotubes as the substrate, nitrogen and phosphorus doping are first completed, and then one or more non-metallic elements such as boron, sulfur, and fluorine are introduced to form a multi-element co-doped structure. The molar ratio of nitrogen to phosphorus is strictly controlled between (3:1) and (5:1). This ratio is the optimal range for electronic structure regulation and active site generation, ensuring the core performance of the modified catalyst.

[0123] Different non-metallic dopants have different electronegativity and electron donation and acceptance capabilities. Multi-element co-doping can break the electron cloud distribution balance of pure nano-carbon substrate, regulate the band structure and charge transfer efficiency of nano-carbon, optimize the interaction between catalyst and fuel molecules and oxygen molecules, reduce the ignition activation energy of mixed fuel, achieve the effect of reducing ignition temperature and promoting complete combustion of fuel, and reduce the generation of fuel-type nitrogen oxides caused by incomplete combustion.

[0124] During multi-element co-doping, the atomic radii and bonding modes of different non-metallic elements differ from those of the nano-carbon substrate. After doping, lattice defects and unsaturated bonds are formed on the surface of the nano-carbon, thereby generating a large number of catalytic active sites. At the same time, the fixed ratio of nitrogen and phosphorus can prevent the active sites from mutually shielding each other, ensuring the exposure and utilization of the sites, allowing the active sites to efficiently catalyze the combustion reaction, optimize the combustion path, inhibit the formation of thermal nitrogen oxides, and improve fuel combustion efficiency.

[0125] The synergistic effect of electronic structure regulation and increased active sites not only reduces the difficulty of fuel ignition and promotes complete combustion at the reaction energy barrier level, but also further inhibits the formation of nitrogen oxides at the reaction pathway level. Ultimately, the metal-free catalyst layer loaded with this modified catalyst can more efficiently assist the stable combustion of natural gas-hydrogen mixed fuel in a three-stage swirl burner, thereby enhancing the overall low-NOx combustion effect.

[0126] Furthermore, defect engineering modification employs one or more of the following methods: plasma etching, ball milling, strong acid oxidation, or high-temperature annealing, to create edge defects or vacancy defects on the surface of nitrogen-doped carbon nanomaterials, thereby increasing the number of edge active sites and inhibiting carbon deposition on the catalyst surface.

[0127] By creating controllable edge / vacancy defects on the catalyst surface through physical / chemical methods such as plasma etching and ball milling, the dual effects of active site expansion and improved anti-coking performance are achieved, thereby enhancing the long-term combustion-supporting and nitrification-suppressing properties of the catalyst. Specifically:

[0128] For nitrogen-doped carbon nanofiber substrates, one or more of the following methods are used: plasma etching, ball milling, strong acid oxidation, or high-temperature annealing. By physical etching, chemical oxidation, or thermal stress control, edge defects and vacancy defects are precisely manufactured on the catalyst surface. Both types of defects are highly efficient catalytic sites for fuel combustion reactions.

[0129] The defect manufacturing process breaks the original complete lattice structure of the carbon substrate, significantly increasing the number and exposure of active sites on the surface edge. These sites can efficiently adsorb natural gas-hydrogen mixed fuel molecules and oxygen molecules, reduce the activation energy of the combustion reaction, and promote the full and rapid combustion of fuel. This not only improves combustion efficiency but also reduces fuel-type nitrogen oxides produced by incomplete combustion. At the same time, it helps to reduce the fuel ignition temperature, forming a synergistic enhancement with the catalytic effect of nitrogen doping.

[0130] The manufactured vacancies / edge defects can alter the charge distribution and surface energy of the catalyst surface. On the one hand, this can promote the rapid conversion of intermediate products during combustion and prevent heavy hydrocarbons from adsorbing and polymerizing on the catalyst surface to form carbon deposits. On the other hand, the defect sites can serve as activation sites for oxygen, making it easier for oxygen molecules to be activated and react with a small amount of carbon deposit precursors on the surface to achieve in-situ elimination of carbon deposits and inhibit carbon deposition from the source.

[0131] This modification process, while expanding the active sites and enhancing the core effects of combustion assistance and nitrogen suppression, solves the problems of easy carbon deposition and masking of active sites in nano-carbon catalysts under high-temperature combustion conditions. It avoids the catalyst efficiency decay due to carbon deposition, ensuring that it maintains stable combustion assistance, ignition point reduction and nitrogen suppression effects in the high-temperature and multi-flue gas conditions of the three-stage swirl burner, supporting the burner's continuous low-NOx stable combustion.

[0132] Furthermore, a metal-free catalyst layer is disposed on the inner wall of the combustion chamber and the surface of the microscale structure of the three-stage swirl burner unit; the nitrogen-doped nano-carbon metal-free catalyst can be prepared using the byproducts of the carbon capture unit.

[0133] In this embodiment, a metal-free catalyst layer loaded with nitrogen-doped nano-carbon metal-free catalyst is specifically disposed on the inner wall of the combustion chamber and the surface of the microscale structure of the three-stage swirl burner unit. This allows the natural gas-hydrogen mixed fuel to fully contact the catalyst layer throughout the entire process of flow, mixing, and combustion. Under the action of the active sites of the catalyst layer, the fuel molecules reduce the ignition activation energy and achieve complete combustion. At the same time, the catalyst layer directly acts on the combustion reaction zone, effectively inhibiting the generation of nitrogen oxides and maximizing the combustion-supporting and nitrogen-suppressing effects of the catalyst. Furthermore, it works synergistically with the burner's staged and zoned structure and the three-stage swirl flow field to further improve combustion stability and low-NOx performance.

[0134] The raw materials for preparing nitrogen-doped nano-carbon metal-free catalysts directly utilize the byproducts of the carbon capture unit, converting the carbon capture byproducts within the system into the carbon substrate of the catalyst. This achieves the cascade recycling of carbon resources, reduces the input of external raw materials, and avoids the secondary treatment and emission of carbon capture byproducts. At the same time, this preparation method integrates the catalyst production process into the overall low-carbon cycle system, linking it with carbon capture to methanol production and low-carbon hydrogen production, further improving the carbon resource utilization rate and overall low-carbon benefits of the entire natural gas-hydrogen dual-fuel combustion system.

[0135] The structured arrangement of the catalyst layer enhances low-NOx combustion and combustion stability from the combustion reaction end, while the cyclic preparation of the catalyst improves the carbon closed loop of the system from the resource utilization end. The synergy of the two allows the three-stage swirl burner unit to not only have better combustion and emission reduction performance, but also become an important link in the system's carbon resource cycle, thus achieving the dual goals of combustion performance optimization and low-carbon resource cycle.

[0136] Furthermore, the carbon capture and resource utilization unit includes a hydrogen production module, a carbon capture module, and a resource utilization module. The hydrogen production module is used to produce low-carbon hydrogen, the carbon capture module is used to capture carbon dioxide, and the resource utilization module couples the captured carbon dioxide with green hydrogen to synthesize methanol.

[0137] In this embodiment, the hydrogen production module produces low-carbon hydrogen using a low-carbon hydrogen production process. A portion of the hydrogen is directly transported to the fuel supply unit as a fuel source for natural gas blending combustion, meeting the hydrogen energy requirements of dual-fuel combustion. Another portion of the green hydrogen is transported to the resource utilization module to provide hydrogen source support for the synthesis of methanol from carbon dioxide, ensuring the low-carbon nature of the hydrogen energy supply throughout the process and reducing system carbon emissions from the fuel end.

[0138] The carbon capture module connects to the three-stage cyclone burner unit, receives the flue gas emitted after combustion, and accurately separates and purifies carbon dioxide from the flue gas through efficient carbon capture processes such as absorption, adsorption, and membrane separation. This achieves source capture and storage of carbon emissions from combustion, significantly reducing the system's carbon dioxide emissions to the outside world. The captured high-purity carbon dioxide is then transported to the resource utilization module as the core carbon source for methanol synthesis, avoiding direct waste of carbon resources.

[0139] The resource utilization module receives high-purity carbon dioxide from the carbon capture module and precisely couples it with green hydrogen from the hydrogen production module in stoichiometric ratio. Under specific catalytic reaction conditions, the two are converted into methanol through a carbon dioxide hydrogenation synthesis process, realizing the high-value resource utilization of carbon dioxide. The synthesized methanol can be exported as an industrial raw material to create economic value, or it can be reused as supplementary fuel for the system to further improve resource utilization.

[0140] The three modules do not work independently, but rather form a synergistic relationship of bidirectional hydrogen supply and directional carbon source flow: the hydrogen production module supplies hydrogen to both the combustion system and the carbon resource recovery process, the carbon capture module provides carbon to the resource recovery process, and the resource recovery process consumes the carbon emissions generated by the system. The three modules connect the carbon production end and the hydrogen consumption end of the entire combustion system, and simultaneously integrate green hydrogen to complete methanol synthesis. This not only improves the low-carbon hydrogen energy supply system within the system, but also realizes the full-process treatment of carbon emission capture, consumption, and resource recovery, allowing the carbon and hydrogen resources of the entire dual-fuel combustion system to form an efficient cycle, maximizing the system's low-carbon nature and resource utilization rate.

[0141] Furthermore, the control unit has functions of data reception, command issuance, linkage coordination, and fault early warning.

[0142] In this embodiment, the aforementioned data receiving is used to receive the flame speed transmitted by the combustion characteristic detection unit in real time. The system collects core combustion detection data such as concentration and boiler load, and simultaneously acquires operational status data from the adaptive control unit, fuel supply unit, three-stage swirl burner unit, and carbon capture and resource utilization unit. All received data is uniformly verified and standardized to provide accurate and effective data for subsequent command issuance and coordinated action.

[0143] The aforementioned instructions are issued based on the received detection data, synchronously forwarding standardized combustion condition data to the adaptive control unit to support the blending ratio calculation; simultaneously, the optimal hydrogen blending ratio control instruction output by the adaptive control unit is received and issued to the fuel supply unit without delay or deviation, clarifying the flow ratio requirements of natural gas and low-carbon hydrogen; in addition, according to the system operating conditions, coordinated instructions for hydrogen supply and carbon capture efficiency adaptation are issued to the carbon capture and resource utilization unit to ensure that the actions of each execution unit are consistent with the overall system control objectives.

[0144] The coordinated linkage is based on the core objectives of low-NOx combustion, stable operation, and low-carbon cycle of the system. It involves cross-module coordinated linkage of various units: according to the fluctuation of boiler load, it synchronously coordinates the total fuel supply of the fuel supply unit, the combustion conditions of the three-stage swirl burner unit, and the hydrogen production of the carbon capture and resource utilization unit, so as to achieve full-chain condition adaptation of load, fuel, combustion and hydrocarbon supply; at the same time, it ensures the synchronization of the action sequence of detection, control, execution and carbon capture, avoids system control imbalance caused by the lag of a single unit, and ensures the smooth operation of the closed-loop process.

[0145] It has built-in logic for monitoring the operating status of the entire system and judging anomalies. It analyzes the operating status data of each unit in real time. When data anomalies, unit operation failures or communication failures are detected, the fault early warning mechanism is immediately triggered. On the one hand, it sends audible and visual or signal early warning information to the system operation and maintenance terminal. On the other hand, it automatically issues temporary emergency control instructions to quickly avoid safety risks, prevent the fault from escalating, and ensure the safe and stable operation of the system.

[0146] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system, characterized in that, include: Control unit; The combustion characteristic detection unit is used to measure flame velocity, nitrogen oxide concentration and boiler load in real time, and transmit the data to the control unit. An adaptive control unit is used to obtain the optimal hydrogen blending ratio based on the detection data; The fuel supply unit is used to receive instructions from the adaptive control unit and precisely mix natural gas and low-carbon hydrogen from the hydrogen production unit according to the instructions, and then deliver them to the burner. The three-stage swirl burner unit is used to burn mixed fuels. The waste heat generated is transferred to the carbon capture unit, and the flue gas is then transferred to the detection unit. The carbon capture and resource utilization unit is used to supply low-carbon hydrogen to the fuel supply unit, and the captured carbon dioxide is recycled to produce methanol.

2. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 1, characterized in that, The combustion characteristic detection unit includes a flame speed detection module for acquiring flame speed, a nitrogen oxide concentration detection module for acquiring nitrogen oxide concentration, and a boiler load detection module for acquiring boiler load. The flame speed detection module, the nitrogen oxide concentration detection module, and the boiler load detection module are all connected to the control unit. The acquired data is processed and transmitted to the control unit in real time.

3. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 1, characterized in that, The adaptive control unit has a built-in fuel combustion characteristic database and performs calculations by coupling detection data to dynamically and adaptively adjust the hydrogen blending ratio to adapt to boiler load fluctuation conditions.

4. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 1, characterized in that, The fuel supply unit includes a mixing module and a flow regulation module. The flow regulation module adjusts the delivery flow rates of natural gas and low-carbon hydrogen according to the instructions of the adaptive control unit to ensure that the mixing ratio meets the control requirements. The mixing module is used to achieve uniform mixing of the two fuels.

5. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 1, characterized in that, The three-stage swirl burner unit adopts a graded and zoned structure, including a central hydrogen enrichment zone and a peripheral natural gas zone, to achieve coordinated and stable combustion of natural gas and low-carbon hydrogen, while suppressing the generation of nitrogen oxides by shortening the flame length; The three-stage swirl burner unit is equipped with a metal-free catalyst layer, which is loaded with a nitrogen-doped nano-carbon metal-free catalyst to assist in the complete combustion of the mixed fuel, reduce the ignition temperature, and further suppress the generation of nitrogen oxides. The nitrogen-doped nano-carbon metal-free catalyst uses graphene or carbon nanotubes as the substrate and is modified by multi-element co-doping and / or defect engineering.

6. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 5, characterized in that, The multi-element co-doping modification involves introducing one or more non-metallic elements from boron, sulfur, and fluorine to form a co-doped structure based on nitrogen doping and phosphorus doping. The molar ratio of nitrogen to phosphorus is controlled between (3:1) and (5:1). The co-doped elements regulate the electronic structure of nano-carbon and increase active sites.

7. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 5, characterized in that, The defect engineering modification employs one or more of the following methods: plasma etching, ball milling, strong acid oxidation, or high-temperature annealing, to create edge defects or vacancy defects on the surface of nitrogen-doped carbon nanomaterials, thereby increasing the number of edge active sites and inhibiting carbon deposition on the catalyst surface.

8. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 5, characterized in that, The metal-free catalyst layer is disposed on the inner wall of the combustion chamber and the surface of the microscale structure of the three-stage swirl burner unit; the nitrogen-doped nano-carbon metal-free catalyst can be prepared using the by-products of the carbon capture unit.

9. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 1, characterized in that, The carbon capture and resource utilization unit includes a hydrogen production module, a carbon capture module, and a resource utilization module. The hydrogen production module is used to produce low-carbon hydrogen, the carbon capture module is used to capture carbon dioxide, and the resource utilization module couples the captured carbon dioxide with green hydrogen to synthesize methanol.

10. The natural gas-hydrogen dual-fuel low-NOx combustion adaptive control system according to claim 1, characterized in that, The control unit has functions of data reception, command issuance, linkage coordination, and fault early warning.

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