A method and system for treating high concentration nitrogen oxide exhaust gas

Abstract

The application discloses a method and system for treating high-concentration nitrogen oxide waste gas. The method is characterized in that high-concentration nitrogen oxide waste gas is mixed with natural gas, and then burned to generate high-temperature atmosphere, so that the nitrogen oxide is converted into nitrogen. The application has the advantages of environmental protection, economy, high efficiency and the like.

Description

Technical Field

[0001] This invention specifically relates to a method and system for treating high-concentration nitrogen oxide waste gas. Background Technology

[0002] Nitrogen oxides (NO) x Nitrous oxide (N₂O), nitric oxide (NO), and nitrogen dioxide (NO₂) are among the air pollutants generated and emitted by industrial production, transportation, and other activities. These pollutants are often caused by NO. x The impact of NO on the environment and various human activities is constantly intensifying and becoming increasingly serious. Therefore, how to effectively reduce NO content is crucial. x Exhaust gas emissions have become one of the key concerns.

[0003] Currently, NO x There are various treatment technologies, mainly including selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), photocatalytic oxidation, and liquid absorption. However, these technologies have at least the following drawbacks: While SCR has high denitrification efficiency, it requires highly corrosive liquid ammonia, ammonia water, or urea solutions in practical applications. This not only places stringent requirements on pipelines and equipment but also increases the amount of reducing agent used as the amount of nitrogen oxides in the exhaust gas increases, leading to a significant increase in costs. SNCR, although simple to operate, is limited by a narrow temperature window and has relatively low denitrification efficiency. Photocatalytic oxidation, in some cases, suffers from insufficient catalyst activity, resulting in low treatment efficiency and insufficient selectivity, easily triggering the generation of non-target reaction byproducts. Liquid absorption poses a risk of secondary pollution and requires regular replacement of the absorbent, increasing operating costs. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for treating high-concentration nitrogen oxide waste gas, which addresses the above-mentioned shortcomings of the existing technology and has the advantages of being environmentally friendly, economical, and highly efficient.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is:

[0006] According to a first aspect of the present invention, a method for treating high-concentration nitrogen oxide waste gas is provided, wherein the nitrogen oxides are converted into nitrogen gas by utilizing the high-temperature atmosphere generated by the combustion of natural gas mixed with the high-concentration nitrogen oxide waste gas.

[0007] Optionally, this method includes the following steps:

[0008] Natural gas is thoroughly mixed with high-concentration nitrogen oxide waste gas to obtain a mixed gas;

[0009] The mixed gas is introduced into the reaction device and ignited, causing the natural gas in it to burn under high temperature conditions to generate a high-temperature atmosphere containing reducing H free radicals, and causing the high-concentration nitrogen oxide waste gas to react with the reducing H free radicals to generate nitrogen gas.

[0010] Optionally, the inlet temperature of the reaction device is controlled to be 300K~900K.

[0011] Optionally, the equivalence ratio of the natural gas is 0.7 to 1.3.

[0012] Optionally, before fully mixing the natural gas with the high-concentration nitrogen oxide waste gas, the step further includes: pre-treating the high-concentration nitrogen oxide waste gas to remove particulate matter, moisture, and impurities from it.

[0013] Optionally, the step further includes: preheating the mixed gas with high-temperature nitrogen obtained in the reaction device before introducing the mixed gas into the reaction device.

[0014] According to a second aspect of the present invention, a system for treating high-concentration nitrogen oxide waste gas is also provided, comprising a mixing device and a reaction device, wherein:

[0015] The mixing device is used to fully mix natural gas with high-concentration nitrogen oxide waste gas to obtain a mixed gas;

[0016] The reaction device is connected to the mixing device and is used to receive the mixed gas and ignite it, so that the natural gas is burned under high temperature conditions to generate a high temperature atmosphere containing reducing H free radicals, so that the high concentration of nitrogen oxide waste gas reacts with the reducing H free radicals to generate nitrogen gas.

[0017] Optionally, the system further includes a pretreatment unit connected to the mixing device, which is used to pretreat the high-concentration nitrogen oxide waste gas before fully mixing the natural gas and the high-concentration nitrogen oxide waste gas to remove particulate matter, moisture and impurities from the high-concentration nitrogen oxide waste gas.

[0018] Optionally, the system further includes a thermal circulation unit, which is connected to the reaction device and the mixing device respectively, and is used to preheat the mixed gas using high-temperature nitrogen obtained in the reaction device before the mixed gas is introduced into the reaction device.

[0019] Optionally, the device further includes a detection unit and a control unit. The detection unit is connected to the reaction apparatus and is used to detect the inlet temperature, reaction pressure, mixed gas flow rate, and reaction product flow rate of the reaction apparatus. The control unit is electrically connected to the detection unit and the reaction apparatus, respectively, and is used to acquire the inlet temperature, reaction pressure, mixed gas flow rate, and reaction product flow rate of the reaction apparatus detected by the detection unit, and to regulate the inlet temperature of the reaction apparatus based on the detection results.

[0020] Beneficial effects:

[0021] The method and apparatus for treating high-concentration nitrogen oxide (NOx) waste gas of the present invention utilize natural gas (CH4) mixed with high-concentration NOx waste gas for treatment and combustion. This directly and effectively converts NOx into nitrogen gas, thereby effectively reducing the NOx content in the waste gas. Pre-treatment of NOx before the SCR system effectively reduces the amount of NOx that the SCR system needs to handle, thus reducing the required catalyst volume and the amount of waste catalyst disposal. This ensures both high efficiency and environmental friendliness. Furthermore, the use of natural gas as fuel is based on mature, stable, and economically efficient technology. The process is greatly simplified, the equipment is simple, and the cost is low. The NOx content in the treated waste gas can be reduced by at least 63%. Compared to existing technologies, this invention effectively reduces the amount of NOx that the SCR system needs to handle, reduces the construction and operating costs of subsequent exhaust gas treatment systems, and combines environmental protection, economy, and high efficiency. It has significant advantages in the field of high-concentration NOx waste gas treatment and can be widely applied in many industrial processes such as industrial production and transportation, providing strong technical support for mitigating environmental pollution and possessing significant application value.

[0022] Furthermore, through a series of rigorous experimental studies under different inlet temperatures and equivalence ratios of the reaction apparatus, this invention has demonstrated exceptional nitrogen oxide removal efficiency under various reaction conditions, fully verifying that this invention can effectively and efficiently treat various high-concentration nitrogen oxide waste gases within a wide operating range, thus fully demonstrating the flexibility and practicality of this invention. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a method and system for treating high-concentration nitrogen oxide waste gas according to an embodiment of the present invention;

[0024] Figure 2 This is a simulation diagram of combustion reaction kinetics in an embodiment of the present invention;

[0025] Figure 3 This is a CFD simulation diagram of an embodiment of the present invention.

[0026] In the diagram: 1-Pretreatment unit; 2-Mixing device; 3-Thermal circulation unit; 4-Reaction device. Detailed Implementation

[0027] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0028] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the invention and are not intended to limit the invention.

[0029] It is understood that, without conflict, the various embodiments and features in the embodiments of the present invention can be combined with each other.

[0030] It is understood that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, while the parts unrelated to the present invention are not shown in the drawings.

[0031] It is understood that each unit or module involved in the embodiments of the present invention may correspond to only one entity structure, or may be composed of multiple entity structures, or multiple units or modules may be integrated into one entity structure.

[0032] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of this invention may occur in a different order than that marked in the accompanying drawings.

[0033] To address the problems of low efficiency, high cost, or secondary pollution in existing nitrogen oxide treatment methods, this invention provides a method for treating high-concentration nitrogen oxide waste gas. This method utilizes the high-temperature atmosphere generated by burning natural gas (CH4) mixed with high-concentration nitrogen oxide waste gas to reduce nitrogen oxide (NOx) concentrations. x It is converted into nitrogen gas (N2).

[0034] Accordingly, the present invention also provides a system for treating high-concentration nitrogen oxide waste gas, including a mixing device and a reaction device, wherein: the mixing device is used to fully mix natural gas with high-concentration nitrogen oxide waste gas to obtain a mixed gas; the reaction device is connected to the mixing device and is used to receive the mixed gas and ignite it, so that the natural gas is burned under high temperature conditions to generate a high-temperature atmosphere containing a large number of reducing H free radicals, so that the high-concentration nitrogen oxide waste gas reacts with the reducing H free radicals to generate nitrogen gas.

[0035] The method and apparatus for treating high-concentration nitrogen oxide waste gas of the present invention utilize natural gas (CH4) mixed with high-concentration nitrogen oxide waste gas for treatment and combustion, which can convert the nitrogen oxides in the waste gas into nitrogen gas, thereby effectively reducing the nitrogen oxide content in the waste gas. Compared with the prior art, the present invention has the advantages of being environmentally friendly, economical, and highly efficient.

[0036] Example 1

[0037] This embodiment discloses a method for treating high-concentration nitrogen oxide waste gas. It utilizes a high-temperature atmosphere containing reducing H free radicals generated from the combustion of natural gas mixed with high-concentration nitrogen oxide waste gas to convert nitrogen oxides into nitrogen gas. Specifically, as follows... Figure 1 As shown, the steps of this method include:

[0038] Natural gas is thoroughly mixed with high-concentration nitrogen oxide waste gas to obtain a mixed gas;

[0039] The mixed gas is introduced into the reaction device and ignited, causing the natural gas in it to burn under high temperature conditions to generate reducing H free radicals, and the high concentration of nitrogen oxide waste gas reacts with the reducing H free radicals to generate nitrogen gas.

[0040] Specifically, high-concentration nitrogen oxide exhaust gases include NO x and air, NO x Including NO, NO2, and N2O, among which NO x The concentration was 40000 mg / Nm 3 ~150000mg / Nm 3 Taking NO2 as an example, the processing steps of this method mainly include: , , The reducing H radicals generated by the combustion and cracking of CH4 not only promote the consumption of NO2, but also promote the consumption of NO, and further promote... The transformation.

[0041] In some implementations, the equivalence ratio of natural gas (i.e., the ratio of the amount of air theoretically required for complete combustion of natural gas to the amount of air actually supplied) is 0.7 to 1.3.

[0042] In some embodiments, the reaction apparatus employs a direct-fired natural gas hot air furnace, with the inlet temperature controlled between 300K and 900K. By controlling the inlet temperature of the reaction apparatus, the combustion reactants carry heat, which improves combustion stability (easier ignition), thereby enabling stable ignition and combustion in environments with higher nitrogen oxide content (more exhaust gas, lower fuel concentration, and difficulty in ignition). Furthermore, different combustion temperatures affect NO... xThe treatment effects differ. Increasing the inlet temperature of the reaction device can raise the maximum combustion temperature. In this method, the inlet temperature of the reaction device is controlled at 300K~900K, and the maximum combustion reaction temperature is 1946.358K~2566.863K, which is conducive to promoting faster reaction.

[0043] In some implementations, the effects of different inlet temperature ranges on NO are taken into account. x The conversion of NO2 to NO has a significant impact. Simulations under different operating conditions, focusing on temperature and equivalence ratio, verified the conversion: Under lean combustion conditions, the inlet temperature of the reactor is controlled at 700K~800K, where NO treatment is most effective and more conducive to treating NO waste gas. Under equivalence combustion conditions, a higher inlet temperature, such as 500K~700K, is beneficial for converting NO2 to NO. Under rich combustion conditions, a higher inlet temperature, such as 300K~400K, is beneficial for converting NO2 to NO, and ultimately, NO... x Emissions are extremely low.

[0044] In this embodiment, under lean combustion conditions, for example, with an equivalence ratio Φ=0.7, the inlet temperature of the reactor is preferably 800K. At this temperature, NO emissions are lowest, with a mole fraction of 0.00897, showing a significant reduction compared to other temperature conditions. x The reduction effect can reach 71% of NO. x reduce.

[0045] Under stoichiometric combustion (i.e., stoichiometric ratio Φ=1) conditions, the inlet temperature of the reaction apparatus is preferably controlled at 300K~500K. At this temperature, it is conducive to the conversion of NO2 to NO, and ultimately NO... x Emissions are extremely low, reaching over 80% NO. x reduce.

[0046] Under fuel-rich conditions, for example, with an equivalence ratio Φ=1.3, the inlet temperature of the reaction apparatus is preferably controlled at 300K~500K. At this temperature, it is conducive to the conversion of NO2 to NO, and ultimately NO... x Emissions are extremely low, reaching over 80% NO. x reduce.

[0047] The above simulations verified that, under lean, stoichiometric, and rich combustion conditions, NO x There are significant differences in emissions between the two systems. Under the same temperature conditions, the NO emissions after treatment under stoichiometric combustion and fuel-rich combustion conditions are significantly different. xThe concentration was lower than that under lean combustion conditions, resulting in better treatment performance. In other words, this method demonstrated exceptional nitrogen oxide removal efficiency under various reaction conditions.

[0048] In some embodiments, before thoroughly mixing the natural gas with the high-concentration nitrogen oxide exhaust gas, the process further includes: pre-treating the high-concentration nitrogen oxide exhaust gas. The pre-treatment includes processes such as filtration, dust removal, and dehumidification to remove particulate matter, moisture, and other impurities from the high-concentration nitrogen oxide exhaust gas, preventing them from interfering with subsequent treatment processes and damaging equipment, and ensuring that the exhaust gas composition is NO. x Primarily composed of air, it creates favorable conditions for subsequent reactions with natural gas.

[0049] In some embodiments, the method further includes: preheating the mixed gas with high-temperature nitrogen obtained in the reaction device before introducing the mixed gas into the reaction device, so that the high temperature generated by combustion can be further utilized through thermal cycling, thereby realizing further utilization of system energy.

[0050] Example 2

[0051] like Figure 1 As shown, this embodiment discloses a system for treating high-concentration nitrogen oxide waste gas, which can be used in the above-described method for treating high-concentration nitrogen oxide waste gas. The system includes a mixing device and a reaction device, wherein:

[0052] A mixing device is used to thoroughly mix natural gas with high-concentration nitrogen oxide waste gas to obtain a mixed gas;

[0053] The reaction device is connected to the mixing device to receive the mixed gas and ignite it, so that the natural gas burns under high temperature conditions to produce reducing H free radicals, which then react with the high-concentration nitrogen oxide waste gas to generate nitrogen gas.

[0054] In this embodiment, the reaction device employs a direct-fired natural gas hot air furnace, constructed from high-temperature and corrosion-resistant materials, which possesses excellent heat insulation properties to minimize heat loss. The reaction device features a rationally designed airflow channel and swirling burner layout, notably incorporating a blunt flame stabilizer structure at the burner outlet. The burner ignites a mixture of high-concentration nitrogen oxide waste gas and natural gas, generating a stable high-temperature flue gas recirculation zone. This provides a stable attachment point for the flame, improving the stability of the flame-to-gas flow under load fluctuations. Furthermore, the disturbance effect separates the mixed gas masses of natural gas and high-concentration nitrogen oxide waste gas, promoting more uniform mixing and creating conditions for subsequent efficient reduction reactions, ensuring complete combustion of the mixture.

[0055] In some embodiments, the device also includes a gas collection system connected to the mixing unit via a reliable natural gas supply pipeline and equipped with precise flow control valves and flow meters to control the natural gas flow rate. In industrial production sites, this system is used to collect gas containing NO. x The waste gas is then transported to a mixing device and mixed with high-concentration nitrogen oxide waste gas according to a preset equivalent ratio.

[0056] In some embodiments, the device further includes a pretreatment unit connected to the mixing device. This pretreatment unit pre-treats the high-concentration nitrogen oxide waste gas before thoroughly mixing it with the natural gas. The pretreatment includes processes such as filtration, dust removal, and dehumidification to remove particulate matter, moisture, and other impurities from the high-concentration nitrogen oxide waste gas, preventing them from interfering with subsequent treatment processes and damaging the equipment, and ensuring that the waste gas composition is NO. x Primarily composed of air, it creates favorable conditions for subsequent reactions with natural gas.

[0057] In some embodiments, the device further includes a thermal circulation unit, which is connected to the reaction device and the mixing device respectively. The thermal circulation unit is used to preheat the mixed gas with high-temperature nitrogen obtained in the reaction device before the mixed gas is introduced into the reaction device, so that the high temperature generated by combustion can be further utilized through thermal circulation, thereby realizing further utilization of system energy.

[0058] In this embodiment, the thermal circulation unit specifically adopts a closed-loop refrigeration and heating circulator, but is not limited to this.

[0059] In some embodiments, the device further includes a detection unit and a control unit, wherein: the detection unit is connected to the reaction device and is used to detect key parameters such as the inlet temperature of the reaction device, the reaction pressure, the flow rate of the mixed gas, and the flow rate of the reaction products; the control unit is electrically connected to the detection unit and the reaction device respectively, and is used to acquire the key parameters such as the inlet temperature of the reaction device, the reaction pressure, the flow rate of the mixed gas, and the flow rate of the reaction products detected by the detection unit, and adjust the operating conditions in a timely manner according to the detection results to regulate the inlet temperature of the reaction device, thereby controlling the combustion temperature by controlling the inlet temperature of the reaction device, and ultimately ensuring stable operation of the reaction to achieve the expected nitrogen oxide emission reduction effect.

[0060] Specifically, adjusting operating conditions in a timely manner based on test results means: taking combustion temperature as the control target, adopting a feedforward-feedback composite regulation strategy, and calculating the basic natural gas flow rate in real time based on the high-concentration nitrogen oxide exhaust gas flow rate and the preset equivalent ratio coefficient (i.e., equivalent ratio), that is, basic natural gas flow rate = preset equivalent ratio coefficient × high-concentration nitrogen oxide exhaust gas flow rate; at the same time, dynamically compensating for temperature deviation through a PID controller (i.e., control unit): if the combustion temperature in the reaction zone is lower than the set value, the natural gas flow correction amount is increased, and vice versa, and finally the valve position command is output.

[0061] The following simulation experiments further detail the methods and apparatus for treating high-concentration nitrogen oxide waste gas described above:

[0062] (1) Simulation Implementation Scheme 1: Combustion Reaction Kinetics Simulation, based on ideal conditions.

[0063] A simulated reaction apparatus was constructed using the combustion reaction kinetics simulation software Chemkin. The apparatus simulated the combustion reaction of a mixture of CH4 and high-concentration nitrogen oxide waste gas (including 3.0675% molar fraction of NO, NO2, or N2O, with the remainder being air) introduced into the reaction apparatus. This simulated reaction apparatus allows for adjustments to physical quantities such as the inlet temperature and equivalence ratio of the reaction apparatus, and can also measure the combustion temperature.

[0064] By changing the inlet temperature and equivalence ratio of the reactor, the combustion reaction of NO2 and CH4 was simulated when the inlet temperature was 300K~900K and the equivalence ratios were 0.7, 1.0 and 1.3 respectively. The three NO concentrations (NO, NO2 and N2O) at the reactor outlet were recorded. x The mole fraction, the results show: Figure 2 As shown, the horizontal axis represents the inlet temperature of the reaction apparatus, and the vertical axis represents the corresponding NO. x The mole fraction is represented by lines of different colors, which indicate different equivalence ratios. Figure 2 It can be seen that as the inlet temperature of the reaction device increases, the amount of nitrogen oxides in the outlet gas of the reaction device after co-combustion decreases. This indicates that controlling the inlet temperature of the reaction device appropriately is beneficial for NO reduction. x From the perspective of overall reaction kinetics analysis, maintaining the inlet temperature of the reaction unit within the range of 500~700K can achieve a relatively ideal NO emission reduction. x Emission reduction effect; among them, the NO emissions at the reactor outlet under lean combustion (Φ=0.7) were significantly higher than those under stoichiometric combustion (Φ=1) and rich combustion (Φ=1.3). The lowest NO emissions were observed at a combustion temperature of 2290K, with a mole fraction of 0.00897, at which point 71% NO was emitted. x Reduce, except NOx Good effect, removes NO under stoichiometric combustion and rich combustion conditions x The effect is better, reaching more than 80% of NO. x reduce.

[0065] Therefore, under the conditions of this embodiment, the method and apparatus for treating high-concentration nitrogen oxide waste gas of the present invention can effectively reduce the nitrogen oxide content in simulated high-concentration nitrogen oxide waste gas, and no obvious harmful by-products are detected during the reaction process. The gas after the reaction is mainly harmless gases such as N2, CO2 and water vapor. It has good treatment effect, high efficiency and environmental protection.

[0066] Through the simulation of the above-mentioned implementation scheme one, from the perspective of chemical reaction, it was demonstrated that the method and device of the present invention reduce NO by utilizing natural gas mixed with high-concentration nitrogen oxide waste gas during combustion. x The proposed solution is feasible and provides a theoretical basis.

[0067] (2) Simulation Implementation Scheme 2: CFD simulation, based on non-ideal conditions such as typical constraints of industrial furnaces.

[0068] Using computational fluid dynamics (CFD) software, a reaction device model was constructed based on an actual industrial furnace (such as a direct-fired natural gas hot blast stove). The power of the reaction device was set at 16kW (corresponding to a waste gas treatment volume of 1.56m³). 3 (Per hour). The fuel was set to CH4, the oxidant to high-concentration nitrogen oxide exhaust gas containing 0.03 moles of NO2, and the excess air coefficient (i.e., the reciprocal of the equivalence ratio) was set to 1.1. In the model, the mature and accurate GRI-2.11 detailed reaction mechanism for predicting NOx formation during CH4 combustion was used for numerical simulation. The flow-reaction coupling was reliably modeled using an EDC model. An optimized k-ε model (model parameter C1ξ changed from 1.44 to 1.60) was used to simulate turbulence, and a standard wall model was used to simulate near-wall turbulence. Parameters for the reaction zone were set (i.e., fuel set to CH4, oxidant set to 0.03 moles of NO2 exhaust gas, and excess air coefficient set to 1.1) to simulate flow, heat transfer, and chemical reactions in the actual reaction process.

[0069] Run the CFD simulation program. During the simulation, use the software's built-in monitoring functions to acquire the flue gas (i.e., the gas exiting the reactor) temperature and outlet NO. x Key data such as concentration, Figure 3 As shown, the different colors at different locations within the reaction apparatus represent differences in the mole fractions of NO and NO2, as well as differences in temperature, at those locations. Figure 3It can be seen that, through CFD simulation of the NO2 and NO content distribution within the reactor, as well as the temperature distribution within the reactor, when the inlet temperature of the reactor is 300K, the NO2 molar fraction in the premixed CH4 / high-concentration nitrogen oxide exhaust gas mixture is 3%, and the equivalent ratio is 0.9. The results indicate that, after co-combustion of CH4 and high-concentration nitrogen oxide exhaust gas containing NO2 in a direct-fired natural gas hot blast stove, although the actual furnace heat loss leads to a decrease in heat and combustion temperature, resulting in a lower reaction temperature and limited generation of reducing H free radicals, when the inlet temperature of the reactor is 300K and the flue gas temperature reaches 1455K, the outlet NO... x The mole fraction is 0.011095, which can achieve 63% NO. x The reduction indicates that even with a low inlet temperature of the reaction unit, considering heat loss during actual combustion (maximum combustion temperature <1700K), considerable NO removal can still be effectively achieved. x The results confirm that the fundamental principle of the above method lies in the chemical action of the reducing H radicals generated during methane combustion cracking on high-concentration nitrogen oxide waste gas, fully demonstrating the high efficiency and practicality of the method of this invention. In actual design, the inlet temperature should be reasonably set to address the combustion temperature and combustion stability caused by specific furnace heat loss, in order to achieve stable and higher NO... x Removal rate.

[0070] Through the simulation implementation scheme two described above, based on typical constraints of an industrial furnace, it was demonstrated that the present invention can still achieve significant NO reduction under non-ideal conditions. x The emission reduction effect can effectively predict the treatment effect of the method of the present invention in practical applications, providing a basis for direct industrialization.

[0071] In summary, the method and apparatus for treating high-concentration nitrogen oxide waste gas of this invention utilizes natural gas (CH4) mixed with high-concentration nitrogen oxide waste gas for treatment and combustion, which can directly and effectively convert nitrogen oxides into nitrogen gas, thereby effectively reducing the nitrogen oxide content in the waste gas. This can significantly reduce the amount of nitrogen oxides that the subsequent tail gas treatment system needs to receive. Taking the SCR system as an example, it can effectively reduce the amount of catalyst required to be installed in the reactor, effectively reduce the amount of waste catalyst to be disposed of, and avoid the problem of handling and disposing of large amounts of waste catalyst. While ensuring efficient treatment, it also takes into account environmental friendliness. At the same time, natural gas as a fuel has mature and stable production technology and high economic benefits. It greatly simplifies the treatment process, with simple equipment and low cost. The nitrogen oxide content in the treated waste gas can be reduced by at least 63%, and the treatment efficiency is high. Compared to existing technologies, this invention effectively reduces the amount of nitrogen oxides (NOx) that the SCR system needs to treat, thereby reducing the construction and operating costs of subsequent exhaust gas treatment systems. It combines environmental friendliness, economy, and high efficiency, demonstrating significant advantages in the treatment of high-concentration NOx waste gas. It can be widely applied in various industrial processes such as industrial production and transportation, providing strong technical support for mitigating environmental pollution and possessing significant application value. Furthermore, through a series of rigorous experimental studies under different inlet temperatures and equivalence ratios of the reaction apparatus, this invention has demonstrated exceptional NOx removal efficiency under various reaction conditions, fully verifying that it can effectively and efficiently treat various types of high-concentration NOx waste gas within a wide operating range, fully showcasing its flexibility and practicality.

[0072] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A method for treating high-concentration nitrogen oxide waste gas, characterized in that, The high-temperature atmosphere generated by burning natural gas mixed with high concentrations of nitrogen oxides converts nitrogen oxides into nitrogen.

2. The method for treating high-concentration nitrogen oxide waste gas according to claim 1, characterized in that, step include: Natural gas is thoroughly mixed with high-concentration nitrogen oxide waste gas to obtain a mixed gas; The mixed gas is introduced into the reaction device and ignited, causing the natural gas in it to burn under high temperature conditions to generate a high-temperature atmosphere containing reducing H free radicals, and causing the high-concentration nitrogen oxide waste gas to react with the reducing H free radicals to generate nitrogen gas.

3. The method for treating high-concentration nitrogen oxide waste gas according to claim 2, characterized in that, The inlet temperature of the reaction device is controlled at 300K~900K.

4. The method for treating high-concentration nitrogen oxide waste gas according to claim 2, characterized in that, The equivalence ratio of the natural gas is 0.7 to 1.

3.

5. The method for treating high-concentration nitrogen oxide waste gas according to claim 2, characterized in that, Before thoroughly mixing the natural gas with the high-concentration nitrogen oxide exhaust gas, the process also includes: The high-concentration nitrogen oxide waste gas is pretreated to remove particulate matter, moisture, and impurities.

6. The method for treating high-concentration nitrogen oxide waste gas according to claim 2, characterized in that, The steps also include: Before the mixed gas is introduced into the reaction device, it is preheated with high-temperature nitrogen gas obtained in the reaction device.

7. A system for treating high-concentration nitrogen oxide waste gas, characterized in that, Includes mixing devices and reaction devices, wherein: The mixing device is used to fully mix natural gas with high-concentration nitrogen oxide waste gas to obtain a mixed gas; The reaction device is connected to the mixing device and is used to receive the mixed gas and ignite it, so that the natural gas is burned under high temperature conditions to generate a high temperature atmosphere containing reducing H free radicals, so that the high concentration of nitrogen oxide waste gas reacts with the reducing H free radicals to generate nitrogen gas.

8. The system for treating high-concentration nitrogen oxide waste gas according to claim 7, characterized in that, It also includes a preprocessing unit. The pretreatment unit is connected to the mixing device and is used to pretreat the high-concentration nitrogen oxide waste gas before fully mixing the natural gas and the high-concentration nitrogen oxide waste gas, so as to remove particulate matter, moisture and impurities from the high-concentration nitrogen oxide waste gas.

9. The system for treating high-concentration nitrogen oxide waste gas according to claim 7, characterized in that, It also includes a thermal cycling unit. The thermal circulation unit is connected to the reaction device and the mixing device respectively, and is used to preheat the mixed gas with high-temperature nitrogen obtained in the reaction device before the mixed gas is introduced into the reaction device.

10. The system for treating high-concentration nitrogen oxide waste gas according to any one of claims 7 to 9, characterized in that, It also includes a detection unit and a control unit. The detection unit is connected to the reaction device and is used to detect the inlet temperature of the reaction device, the reaction pressure, the flow rate of the mixed gas, and the flow rate of the reaction products. The control unit is electrically connected to the detection unit and the reaction device, respectively, and is used to acquire the inlet temperature, reaction pressure, mixed gas flow rate and reaction product flow rate of the reaction device detected by the detection unit, and to regulate the inlet temperature of the reaction device according to the detection results.

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