Flue gas denitration treatment method for hot-blast stove

Abstract

The invention relates to the field of waste gas treatment, and particularly discloses a flue gas denitration treatment method for a hot blast stove. The flue gas denitration treatment method for the hot-blast stove comprises the following steps that the temperature of flue gas exhausted by the hot-blast stove is 220-270 DEG C, the flue gas is introduced into a denitration reactor, a catalyst is arranged in the denitration reactor, and after the flue gas enters the denitration reactor, an ammonia water solution with the concentration of 20-25 wt% is sprayed into the flue gas for denitration, the ammonia water solution is sprayed into the denitration reactor after being atomized, and an included angle of 30-45 degrees is formed between the spraying angle of the ammonia water solution and the flowing direction of the flue gas. The flue gas denitration treatment method for the hot blast stove has the advantages of being low in cost and high in denitration efficiency.

Description

Technical Field

[0001] This application relates to the field of waste gas treatment, and more specifically, it relates to a method for denitrification treatment of flue gas from a hot blast stove. Background Technology

[0002] With increasingly stringent global environmental regulations, industrial waste gas treatment has become a core issue in the field of environmental protection. Particularly in the control of nitrogen oxides (NOx) pollution, countries are continuously lowering emission limits for flue gas, driving the research and application of flue gas denitrification technology into a rapid development phase. As a key treatment method for emission sources such as industrial kilns and coal-fired power plants, efficient and economical denitrification technology has become an important support for industry transformation and upgrading, and its technological iteration and optimization are directly related to the achievement of pollutant emission reduction targets. Currently, selective catalytic reduction (SCR) and non-selective catalytic reduction (SNCR) technologies constitute the mainstream solutions for industrial denitrification. SCR technology relies on the catalytic action of a catalyst to efficiently reduce NOx to nitrogen (N2) and water (H2O) within a temperature range of 200-400℃, with denitrification efficiencies typically reaching 80%-95%. However, this technology faces the bottleneck of high catalyst costs, and precious metal catalysts are susceptible to poisoning and deactivation by heavy metals and sulfur oxides in flue gas, increasing the difficulty of operation and maintenance. SNCR technology involves injecting reducing agents such as ammonia or urea into high-temperature flue gas (850-1100℃) to directly reduce NOx. Its advantages include simple equipment structure, low initial investment, and suitability for small to medium-sized industrial furnaces. However, this technology is subject to strict temperature window limitations; excessively low temperatures lead to incomplete reducing agent reaction, while excessively high temperatures easily trigger ammonia decomposition. The denitrification efficiency is typically only 30%-60%, and there is a risk of ammonia escape causing secondary pollution. Summary of the Invention

[0003] In order to provide a novel treatment method with low cost and high denitrification efficiency, this application provides a method for denitrification treatment of flue gas from a hot blast stove.

[0004] The hot blast furnace flue gas denitrification treatment method provided in this application adopts the following technical solution: A method for denitrification of flue gas from a hot blast stove includes the following steps: The flue gas temperature discharged from the hot blast furnace is 220-270℃. The flue gas is passed into the denitrification reactor, which is equipped with a catalyst. After the flue gas enters the denitrification reactor, an ammonia solution with a concentration of 20-25wt% is injected into the flue gas for denitrification. The ammonia solution is atomized and sprayed into the denitrification reactor. The spray angle of the ammonia solution is 30-45° with the flue gas flow direction.

[0005] By adopting the above technical solution, this solution targets the characteristics of the 220-270℃ flue gas discharged from the hot blast stove. It employs a combination of catalytic reaction within the denitrification reactor and atomized injection of ammonia solution, forming a denitrification system adapted to the medium-temperature range. The flue gas temperature of 220-270℃ falls precisely within the effective reaction temperature window of SCR technology, providing a fundamental condition for catalyst activity. The optimized concentration of 20-25wt% ammonia solution avoids the problem of insufficient reducing agent due to low concentrations while reducing the risk of ammonia escape that may occur with high concentrations. Atomized injection disperses the ammonia solution in the form of tiny droplets, ensuring sufficient contact with the flue gas. The 30-45° injection angle design prolongs the contact time between the reducing agent and the flue gas, enhancing mixing uniformity and thus improving the completeness of the denitrification reaction, achieving high denitrification efficiency under medium-temperature conditions.

[0006] Optionally, the ammonia-nitrogen molar ratio is controlled at 0.8-1.1 when the ammonia solution is sprayed in.

[0007] By adopting the above technical solution, controlling the ammonia-to-nitrogen molar ratio during ammonia injection within the range of 0.8-1.1 ensures sufficient reaction between ammonia and NOx while avoiding ammonia escape due to excess ammonia. This molar ratio range maximizes ammonia utilization, ensuring denitrification efficiency while reducing the risk of secondary pollution and lowering operating costs.

[0008] Optionally, the catalyst component comprises, by mass percentage, 0.5-1.5% vanadium pentoxide, 5-8% tungsten oxide, and the balance being titanium dioxide particles, and the catalyst has a specific surface area ≥60 m². 2 / g, pore volume 0.25-0.35cm 3 / g.

[0009] By adopting the above technical solution, in the catalyst composition, 0.5-1.5% vanadium pentoxide serves as the active component, providing highly efficient catalytic active centers to promote the NOx reduction reaction; 5-8% tungsten oxide enhances the catalyst's thermal stability and resistance to sulfur poisoning, extending its service life; the remaining titanium dioxide serves as a support, possessing a large specific surface area (≥60m²). 2 / g) and suitable pore volume (0.25-0.35cm³). 3 The catalyst system ( / g) provides excellent dispersion support for the active components, increases the contact opportunities between reactants and active sites, and improves catalytic reaction efficiency. This catalyst system exhibits high catalytic activity and stability in the low-temperature range, effectively reducing the catalyst cost of SCR technology while ensuring efficient denitrification.

[0010] Optionally, the catalyst further includes 1-3 wt% MnO. x -CeO2 composite additive, wherein MnO x-CeO2 composite additives contain MnO by mass ratio x CeO2 = 1:1.5, the MnO x - In the CeO2 composite additive, the molar ratio of Mn3+:Mn4+ is 1:(1.2-1.5).

[0011] By adopting the above technical solution, 1-3 wt% MnO is added to the catalyst. x -CeO2 composite additive, in which MnO x With a CeO2 mass ratio of 1:1.5 and a Mn3+ to Mn4+ molar ratio of 1:(1.2-1.5), the catalyst performance can be further optimized. CeO2 has excellent oxygen storage and release capabilities, can regulate the oxygen concentration in the reaction atmosphere, and enhance the catalyst's resistance to oxygen inhibition; MnO2... x It provides abundant active oxygen species and redox sites, enhancing the catalyst's adsorption and reduction capabilities for NOx. The synergistic effect of these two factors significantly improves the catalyst's low-temperature activity, resistance to sulfur and heavy metal poisoning, broadens its applicable temperature range, extends its service life, and enables the catalyst to maintain highly efficient and stable denitrification performance even under complex flue gas conditions.

[0012] Optionally, during the denitrification process, a nitrogen mixture containing 5-10 vol% hydrogen is injected into the flue gas, and the injection amount is 0.1-0.5% of the flue gas volume flow rate.

[0013] By adopting the above technical solution, a nitrogen mixture containing 5-10 vol% hydrogen is injected during the denitrification process, with the injection volume being 0.1-0.5% of the flue gas volume flow rate. Hydrogen, as a reducing gas, can synergistically participate in the NOx reduction reaction with ammonia. Especially under low-temperature conditions, the addition of hydrogen can increase the activation energy of the reaction, accelerate the reaction rate, and improve the low-temperature denitrification efficiency. Simultaneously, the presence of hydrogen can lower the decomposition temperature of ammonia, reduce ammonia loss at low temperatures, improve ammonia utilization, and further reduce the risk of ammonia escape. This measure allows denitrification to remain highly efficient at lower temperatures, reducing operating costs.

[0014] Optionally, before injecting the ammonia solution, an activator solution containing ammonium formate is injected into the flue gas, wherein the molar ratio of ammonium formate to ammonia is 1:(10-15), and the atomized particle size of the activator solution is ≤20μm.

[0015] Optionally, by adopting the above technical solution, a microwave radiation device is installed inside the denitrification reactor, wherein the microwave radiation device has a microwave frequency of 2.45 GHz and a power density of 0.5-3 kW / m². 3 .

[0016] By adopting the above technical solution In summary, this application has the following beneficial effects: 1. Because this application targets the characteristics of flue gas at 220-270℃, it significantly improves the reaction rate and NOx conversion rate by optimizing the catalyst formula, atomizing and injecting the reducing agent, and combining microwave radiation and hydrogen injection, thereby achieving efficient denitrification in the medium temperature range.

[0017] 2. In this application, the ammonia-nitrogen molar ratio (0.8-1.1) is precisely controlled and the ammonium formate activator works synergistically to reduce ammonia escape and waste of reducing agent; the catalyst anti-poisoning design reduces maintenance costs, and while improving the denitrification effect, it also takes into account the prevention and control of secondary pollution and the economic efficiency of operation.

[0018] 3. The method of this application uses MnO x -CeO2 composite additives broaden the active temperature window, activation pretreatment improves catalyst adaptability, microwave and hydrogen synergistically enhance the removal capacity of low-concentration NOx, and with pore volume and specific surface area optimization, improve the system's tolerance to flue gas fluctuations and ensure long-term stable operation. Detailed Implementation

[0019] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources. Example

[0020] Example 1 A method for denitrification of flue gas from a hot blast stove: The flue gas discharged from the hot blast stove of the steel plant is cooled to 245℃, the flue gas flow rate is controlled at 5m / s, and the flue gas is then introduced into the denitrification reactor.

[0021] The denitrification reactor is packed with a titanium dioxide-based catalyst, whose composition by weight percentage is 1.0% vanadium pentoxide, 6.5% tungsten oxide, and the balance being titanium dioxide. The catalyst has a specific surface area of ​​80 m². 2 / g, pore volume 0.30cm 3 / g, catalyst loading amount 1m 3 .

[0022] A 22.5 wt% ammonia solution was sprayed into the denitrification reactor through an atomizing nozzle at a 37.5° angle to the flue gas flow direction. The injection rate of the ammonia solution was adjusted by a flow controller to maintain the ammonia-nitrogen molar ratio at 0.95.

[0023] The flue gas stays in the reactor for 3 seconds to carry out the denitrification reaction, and the flue gas after the reaction is discharged by an induced draft fan.

[0024] Example 2-3 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that the temperature of the flue gas introduced in Example 2 is 220°C, while the temperature of the flue gas introduced in Example 3 is 270°C.

[0025] Examples 4-5 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that the concentration of ammonia solution in Example 4 is 20 wt%, and the concentration of ammonia solution in Example 5 is 25 wt%.

[0026] Examples 6-7 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that in Example 6, the injection angle of the ammonia solution is at a 30° angle to the flue gas flow direction, while in Example 7, the injection angle of the ammonia solution is at a 45° angle to the flue gas flow direction.

[0027] Examples 8-9 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that in Example 8, the ammonia-nitrogen molar ratio is controlled at 0.8 after the ammonia solution is injected, while in Example 9, the ammonia-nitrogen molar ratio is controlled at 1.1 when the ammonia solution is used.

[0028] Examples 10-11 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that in Example 10, the titanium dioxide-based catalyst composition is 0.5% vanadium pentoxide and 5% tungsten oxide by mass percentage, with the balance being titanium dioxide; in Example 11, the titanium dioxide-based catalyst composition is 1.5% vanadium pentoxide and 8% tungsten oxide by mass percentage, with the balance being titanium dioxide.

[0029] Examples 12-13 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that the catalyst specific surface area in Example 12 is 60 m². 2 / g, the catalyst in Example 13 has a specific surface area of ​​40m². 2 / g.

[0030] Example 14 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that the catalyst also includes 2 wt% MnO. x -CeO2 composite additive, MnO x -CeO2 composite additives contain MnO by mass ratio x CeO2 = 1:1.5, MnO x -CeO2 composite additives Mn (molar ratio) 3+ :Mn 4+ = 1:1.35.

[0031] Example 15 A method for denitrification of flue gas from a hot blast stove: The difference from Example 15 is that the catalyst also includes 1 wt% MnO. x -CeO2 composite additive.

[0032] Example 16 A method for denitrification of flue gas from a hot blast stove: The difference from Example 15 is that the catalyst also includes 3 wt% MnO. x -CeO2 composite additive.

[0033] Example 17 A method for denitrification of flue gas from a hot blast stove: the difference from Example 15 is the presence of MnO x -CeO2 composite additives contain MnO by mass ratio x CeO2 = 1:1.

[0034] Example 18 A method for denitrification of flue gas from a hot blast stove: the difference from Example 15 is the presence of MnO x -CeO2 composite additives contain MnO by mass ratio x CeO2 = 1:2.

[0035] Example 19 A method for denitrification of flue gas from a hot blast stove: the difference from Example 15 is the presence of MnO x -In the CeO2 composite additive, the molar ratio of Mn3+:Mn4+ is 1:1.2.

[0036] Example 20 A method for denitrification of flue gas from a hot blast stove: the difference from Example 15 is the presence of MnO x -In the CeO2 composite additive, the molar ratio of Mn3+:Mn4+ is 1:1.5.

[0037] Example 21 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that a nitrogen mixture containing 8 vol% hydrogen is injected into the flue gas during the denitrification process, and the injection amount is 0.3% of the flue gas volume flow rate.

[0038] Example 22 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that a nitrogen mixture containing 8 vol% hydrogen is injected into the flue gas during the denitrification process, and the injection amount is 0.1% of the flue gas volume flow rate.

[0039] Example 23 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that a nitrogen mixture containing 8 vol% hydrogen is injected into the flue gas during the denitrification process, and the injection amount is 0.5% of the flue gas volume flow rate.

[0040] Example 24 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that, before injecting the ammonia solution, an activator solution containing ammonium formate is injected into the flue gas, the molar ratio of ammonium formate to ammonia is 1:13, and the atomized particle size of the activator solution is ≤20μm.

[0041] Example 25 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that, before injecting the ammonia solution, an activator solution containing ammonium formate is injected into the flue gas, the molar ratio of ammonium formate to ammonia is 1:10, and the atomized particle size of the activator solution is ≤20μm.

[0042] Example 26 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that, before injecting the ammonia solution, an activator solution containing ammonium formate is injected into the flue gas, the molar ratio of ammonium formate to ammonia is 1:15, and the atomized particle size of the activator solution is ≤20μm.

[0043] Example 27 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that a microwave radiation device is installed inside the denitrification reactor. The microwave radiation device is set with a microwave frequency of 2.45 GHz and a power density of 1.5 kW / m³. 3 .

[0044] Comparative Example Comparative Example 1 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that after the flue gas enters the denitrification reactor, an ammonia solution with a concentration of 15wt% is injected into the flue gas for denitrification.

[0045] Comparative Example 2 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that after the flue gas enters the denitrification reactor, an ammonia solution with a concentration of 30wt% is injected into the flue gas for denitrification.

[0046] Comparative Example 3 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that the injection angle of the ammonia solution is at a 20° angle to the flue gas flow direction.

[0047] Comparative Example 4 A method for denitrification of flue gas from a hot blast stove: The difference from Example 1 is that the injection angle of the ammonia solution is at a 55° angle to the flue gas flow direction.

[0048] Performance testing NOx concentration detection The NOx concentration in the flue gas was monitored online using an ultraviolet spectrophotometer (referring to HJ479-2009 "Determination of Nitrogen Oxides (Nitric Oxide and Nitrogen Dioxide) in Ambient Air - Naphthylethylenediamine Hydrochloride Spectrophotometric Method"), and the denitrification efficiency was calculated. Denitrification efficiency = (C 初始 -C 处理后 ) / C 初始 ×100% Ammonia slip was detected using the dilute sulfuric acid absorption-indophenol blue spectrophotometric method (referring to HJ533-2009 "Determination of Ammonia in Ambient Air and Exhaust Gas - Nessler's Reagent Spectrophotometric Method") to detect the NH3 concentration in the emitted flue gas, with a control standard of ≤5ppm.

[0049] Table 1 Detection Data Combining Example 1 and Comparative Examples 1-2 with Table 1, it can be seen that when the concentration of the ammonia solution is within the 20-25 wt% range defined in claim 1 (22.5 wt% in Example 1), the denitrification efficiency (92.5%) and ammonia slip control (3.1 ppm) are significantly better than those with concentrations below 20 wt% (15 wt% in Comparative Example 1, efficiency 78.5%, slip 5.2 ppm) and above 25 wt% (30 wt% in Comparative Example 2, efficiency 80.2%, slip 8.7 ppm). This indicates that the 20-25 wt% ammonia concentration range can ensure sufficient reducing agent while avoiding excessive ammonia slip due to excessive concentration or incomplete reaction due to excessively low concentration, making it the optimal range that balances efficiency and environmental friendliness. Combining Example 1 and Comparative Examples 3-4 with Table 1, it can be seen that when the ammonia solution injection angle is within the 30-45° range defined in claim 1 (37.5° in Example 1), the denitrification efficiency (92.5%) and ammonia slip (3.1 ppm) are significantly better than those with angles less than 30° (20° in Comparative Example 3, efficiency 76.3%, slip 6.5 ppm) and greater than 45° (55° in Comparative Example 4, efficiency 75.1%, slip 7.2 ppm). This is because an injection angle of 30-45° allows the atomized ammonia solution to form an optimal mixing path with the flue gas, prolonging the contact time. An angle that is too small can easily lead to the reducing agent concentrating locally, while an angle that is too large can easily be carried away by the flue gas, both of which reduce the sufficiency of the reaction. Based on Examples 1-3 and Table 1, it can be seen that when the flue gas temperature is within the range of 220-270℃ as defined in claim 1, the denitrification efficiency exhibits the optimal trend at the median value: Example 1 (245℃) has the highest efficiency of 92.5%, while Examples 2 (220℃) and 3 (270℃) have efficiencies of 89.2% and 88.6%, respectively. This result is consistent with the activity temperature window characteristics of the medium-temperature SCR catalyst. At 245℃, the catalytic efficiency of the catalyst's active sites is most fully utilized. Temperature deviations from the median value lead to a slight decrease in activity, but it still remains at a high level, verifying the adaptability of this temperature range for denitrification of flue gas from hot blast stoves. Combining Examples 1, 4, and 5 with Table 1, it can be seen that within the 20-25 wt% ammonia solution concentration range defined in claim 1, the denitrification efficiency and ammonia slip exhibit a superior intermediate value: Example 1 (22.5 wt%) has an efficiency of 92.5% and a slip of 3.1 ppm, which is better than Example 4 (20 wt%, efficiency 90.1%, slip 2.8 ppm) and Example 5 (25 wt%, efficiency 89.8%, slip 4.2 ppm). This indicates that a concentration of 22.5 wt% can achieve the best balance between the reducing agent supply and the atomization effect. Too low a concentration may lead to insufficient reducing agent, while too high a concentration may easily cause an increase in ammonia slip due to local overdose. Combining Examples 1, 6, and 7 with Table 1, it can be seen that within the 30-45° injection angle range defined in claim 1, the denitrification effect increases as the angle approaches the median value (37.5°): Example 1 (37.5°) has the highest efficiency of 92.5%, while Examples 6 (30°, 91.0% efficiency) and 7 (45°, 90.5% efficiency) are slightly lower, and the ammonia slip also shows the same trend. This is because the 37.5° angle allows the atomized ammonia water and flue gas to form a more uniform cross-mixing flow field, resulting in a more balanced distribution of the reducing agent within the reactor, and a higher reaction contact efficiency than at the end angle. Combining Examples 1, 8, and 9 with Table 1, it can be seen that within the ammonia-nitrogen molar ratio range of 0.8-1.1 defined in claim 2, the median value (0.95 in Example 1) shows the best performance: the efficiency of 92.5% is significantly higher than that of Example 8 (0.8, efficiency 87.6%) and Example 9 (1.1, efficiency 90.3%), and the ammonia slip of 3.1 ppm is lower than that of Example 9 (4.5 ppm). This result verifies the value of precise control of the ammonia-nitrogen ratio: at 0.8, insufficient reducing agent leads to incomplete reaction; at 1.1, excessive reducing agent causes increased ammonia slip; while 0.95 can achieve near-complete conversion of the reactants. As can be seen from Examples 1, 10-20 and Table 1, the addition of MnO as defined in claims 4-5... xAfter adding the CeO2 composite additive, the denitrification efficiency was significantly improved (92.1%-95.8% in Examples 14-20), far exceeding that of Example 1 (92.5%) without the additive and Examples 10-12 (88.3%-89.5%) containing only the basic components. Specifically, Example 14 (2wt% additive, MnO2) showed a significant improvement. x CeO2 = 1:1.5, Mn 3+ :Mn 4+ The ratio of MnO₂ to O₂ (1:1.35) achieved the highest efficiency of 95.8%, verifying the synergistic catalytic effect of the composite additive—a specific ratio of MnO₂. x It can enhance oxygen transport capacity with CeO2, while the optimized Mn ion valence ratio can improve the electron transfer efficiency of active sites, and the effect is best when the amount of adjuvant is in the middle value range of 1-3 wt%. As can be seen from Examples 1 and 21-23 and Table 1, the denitrification efficiency is significantly improved after injecting the hydrogen-nitrogen mixture as defined in claim 6 compared to Example 1 (92.5%): Example 21 (0.3% injection amount) has the highest efficiency of 94.3%, while Examples 22 (0.1%) and 23 (0.5%) have efficiencies of 92.0% and 92.8%, respectively. This is because hydrogen can form a reducing microenvironment on the catalyst surface, promoting the reduction reaction of NOx, and the 0.3% injection amount can achieve the best balance between enhancing the reaction and controlling energy consumption. Excessive injection (0.5%) results in limited efficiency improvement due to increased side reactions between hydrogen and oxygen. Combining Examples 1 and 24-26 with Table 1, it can be seen that the denitrification efficiency is significantly improved after adding the ammonium formate activator as defined in claim 7: Example 24 (ammonium formate to ammonia molar ratio 1:13) has the highest efficiency of 95.1%, while Examples 25 (1:10) and 26 (1:15) have efficiencies of 93.2% and 93.6% respectively, both higher than the 92.5% of Example 1. The active species generated by the decomposition of ammonium formate can pre-activate the catalyst surface, enhancing its adsorption capacity for ammonia and NOx. The 1:13 ratio achieves the optimal balance between activation effect and cost control; deviations from the median value can lead to insufficient activation or waste of additives. As can be seen from Examples 1 and 27 and Table 1, after adding the microwave radiation device as defined in claim 8, the denitrification efficiency increased from 92.5% in Example 1 to 96.2% in Example 27, the ammonia slip decreased from 3.1 ppm to 2.0 ppm, and the reaction efficiency was significantly improved. This is because 2.45 GHz, 1.5 kW / m 3 Microwave radiation energy enhances the reaction rate of catalyst active sites through thermal and non-thermal effects, and promotes the diffusion of reactant molecules. This verifies the strengthening effect of microwave-assisted catalytic denitrification reaction, and is an effective means to improve overall efficiency. This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for treating flue gas of a hot blast stove for denitration, characterized by, The method comprises the following steps: The flue gas discharged from the hot blast stove has a temperature of 220-270 DEG C, and the flue gas is introduced into a denitration reactor, which is provided with a catalyst, and after the flue gas enters the denitration reactor, ammonia water solution with a concentration of 20-25 wt% is sprayed into the flue gas for denitration, the ammonia water solution is atomized and then sprayed into the denitration reactor, and the spraying angle of the ammonia water solution forms an angle of 30-45 DEG with the flowing direction of the flue gas.

2. The method for flue gas denitration treatment of a hot blast stove according to claim 1, characterized in that: The ammonia nitrogen molar ratio after spraying the ammonia water solution is controlled to be 0.8-1.

1.

3. The method of claim 1, wherein the method is characterized by: The catalyst component comprises 0.5-1.5% vanadium pentoxide, 5-8% tungsten oxide and the balance of titanium dioxide particles in terms of mass percentage, the specific surface area of the catalyst is greater than or equal to 60 m² / g, and the pore volume is 0.25-0.35 cm³ / g.

4. The method of claim 3, wherein the method is characterized by: The catalyst also includes 1-3 wt% of MnO x - CeO2 composite adjuvant.

5. The method for flue gas denitration treatment of a hot blast stove according to claim 4, characterized in that: MnO x MnO x :CeO2=1:1.5, MnO x Mn 3+ :Mn 4+ =1:(1.2-1.5).

6. The method of claim 1, wherein the method is characterized by: During the denitration process, nitrogen mixed gas containing 5-10 vol% hydrogen is also injected into the flue gas, and the injection amount is 0.1-0.5% of the volume flow of the flue gas.

7. The method of claim 1, wherein the method is characterized by: Before spraying the ammonia water solution, an activator solution containing ammonium formate is injected into the flue gas, the molar ratio of the ammonium formate to the ammonia water is 1:(10-15), and the atomized particle size of the activator solution is less than or equal to 20 μm.

8. The method of claim 1, wherein the method is characterized by: The denitration reactor is provided with a microwave radiation device, the microwave frequency of the microwave radiation device is 2.45 GHz, and the power density is 0.5-3 kW / m³.

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