Dry-process integrated flue gas treatment system for flue gas desulfurization and denitrification

Abstract

The utility model belongs to the technical field of flue gas purification, and particularly relates to a dry-process integrated flue gas treatment system for flue gas desulfurization and denitrification. The system at least comprises an electric dust remover, an induced draft fan and a desulfurization and denitrification reaction tower which are sequentially communicated, a discharge port is formed in the bottom end of the desulfurization and denitrification reaction tower and communicated with a washing and dewatering device, the washing and dewatering device is communicated with a neutralization and oxidation desulfurization and denitrification section, and the neutralization and oxidation desulfurization and denitrification section is communicated with a desulfurization and denitrification tower. An activated aluminum oxide stacking layer is arranged in the desulfurization and denitrification reaction tower. According to the utility model, the activated aluminum oxide layer is adopted for catalysis, so that sulfur dioxide and nitrogen oxide are integrally removed by a dry method. The catalyst has good performance, is simple in regeneration mode and can be repeatedly used.

Description

Technical Field

[0001] This utility model belongs to the field of flue gas purification technology, specifically relating to a dry integrated flue gas treatment system for flue gas desulfurization and denitrification. Background Technology

[0002] With the rapid development of industrialization, air pollution problems caused by the use of coal-fired power generation have become increasingly prominent. For example, the flue gas generated in kilns in steel, cement, building materials, glass, and metallurgy industries contains large amounts of pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter, which pose a great threat to human health and the ecological environment. Excessive emissions of nitrogen oxides and sulfur dioxide not only cause serious damage to the human respiratory system, but also cause a series of environmental problems such as acid rain, photochemical pollution, and ozone layer depletion.

[0003] Currently, the most mature and efficient denitrification process in China is selective catalytic reduction (SCR) denitrification. However, due to the difficulty in controlling catalyst activity and the large-scale use of ammonia during production, its application cost is high. Desulfurization mostly employs wet desulfurization technology, typically using limestone slurry as the desulfurizing agent. While it offers high desulfurization efficiency, it consumes a large amount of energy and water, and the desulfurization products are difficult to treat. Denitrification and desulfurization of flue gas are two crucial control indicators, and currently, there is no mature integrated desulfurization and denitrification equipment applicable to the production field. Utility Model Content

[0004] To address the shortcomings of existing technologies, this invention provides a dry integrated flue gas treatment system for desulfurization and denitrification. This invention utilizes an activated alumina layer for catalysis, achieving integrated dry removal of sulfur dioxide and nitrogen oxides. The catalyst exhibits good performance, has a simple regeneration method, and can be reused.

[0005] The technical solution provided by this utility model is as follows:

[0006] A dry integrated flue gas treatment system for desulfurization and denitrification includes an electrostatic precipitator, an induced draft fan, and a desulfurization and denitrification reaction tower arranged in sequence. The bottom end of the desulfurization and denitrification reaction tower has a discharge port, which is connected to a washing and dewatering device. The washing and dewatering device is connected to a neutralization oxidation desulfurization and denitrification section. An activated alumina stockpile is set inside the desulfurization and denitrification reaction tower.

[0007] In the above technical solution:

[0008] After dust removal by an electrostatic precipitator, the raw flue gas enters an integrated denitrification and desulfurization reactor. Nitric oxide in the flue gas reacts simultaneously with oxygen and sulfur dioxide under the action of a catalyst to produce sulfur trioxide and nitrogen dioxide. Due to the catalyst's strong hygroscopic properties, sulfur trioxide, nitrogen dioxide, and excess sulfur dioxide are also adsorbed by the catalyst to form sulfuric acid, nitric acid, and sulfurous acid. Once the catalyst is saturated with sulfuric acid, nitric acid, and sulfurous acid, it is washed, dried, and then sent back to the reaction tower for denitrification and desulfurization. The washed acid solution is neutralized, oxidized, and filtered before being reused. This method primarily activates the oxidizing properties of sulfur dioxide and nitric oxide, oxidizing sulfur dioxide to sulfur trioxide and simultaneously oxidizing nitric oxide to nitrogen dioxide. This converts the difficult-to-remove nitric oxide in the flue gas into nitrogen dioxide, which is then adsorbed by the catalyst and subsequently removed by desorption.

[0009] Main reaction equations in the denitrification and desulfurization reaction tower:

[0010] NO + SO₂ + O₂ → NO₂ + SO₃

[0011] 2SO2 + 2H2O + O2 → 2H2SO4

[0012] 4NO2 + 2H2O + O2 → 4HNO3

[0013] SO3 + H2O → H2SO4

[0014] Possible side reaction equations within the denitrification reaction tower:

[0015] 2NO2 + 4SO2 → N2 + 4SO3

[0016] 2NO + 2H₂SO₃ → N₂ + 2H₂SO₄

[0017] 2NO + O2 + 4H2SO3 → N2 + 4H2SO4

[0018] 2NO + O2 → 2NO2

[0019] 3NO2 + H2O → 2HNO3 + NO

[0020] NO2 + NO + H2O → 2HNO2

[0021] Main reaction equations in the neutralization oxidation tower:

[0022] H₂SO₄ + CaCO₃ → CaSO₄ + H₂O + CO₂

[0023] H₂SO₃ + CaCO₃ → CaSO₃ + H₂O + CO₂

[0024] 2CaSO3 + O2 → 2CaSO4

[0025] 2HNO3+CaCO3→Ca(NO3)2+H2O+CO2

[0026] 2HNO2+CaCO3→Ca(NO2)2+H2O+CO2

[0027] Ca(NO2)2 + O2 → Ca(NO3)2

[0028] Furthermore, the system also includes:

[0029] A dehydrator, which is connected to the top of the desulfurization and denitrification reaction tower;

[0030] And a slag removal device that sends the catalyst residue in the washing and dewatering device to the dewatering machine.

[0031] Furthermore, a gap is left between the top of the activated alumina stockpile and the top plate of the desulfurization and denitrification reaction tower. An air inlet and an air outlet are respectively provided on both sides of the bottom of the desulfurization and denitrification reaction tower. A return air port is provided at the top of the desulfurization and denitrification reaction tower. The air outlet is connected to the return air port, and the air inlet is connected to the induced draft fan. Multiple layers of stainless steel wire mesh are respectively provided at the air inlet and the air outlet.

[0032] Specifically, the neutralization oxidation desulfurization and denitrification section includes a limestone pipeline mixer, a neutralization oxidation tower, a gypsum filter, and a nitrate evaporator, which are connected in sequence.

[0033] Furthermore:

[0034] The gypsum filter has a clear liquid outlet;

[0035] The clear liquid outlet is connected to the washing and dehydration device or the limestone pipeline.

[0036] Specifically:

[0037] The washing and dehydration device is equipped with a stirring device;

[0038] The neutralization and oxidation tower is equipped with an oxidation fan.

[0039] Specifically:

[0040] The electrostatic precipitator is connected to the original flue gas inlet pipe;

[0041] The desulfurization and denitrification reaction tower is connected to the emission chimney.

[0042] Furthermore:

[0043] NOx, SO2 and pressure sensors are installed in the pipeline connecting the induced draft fan and the desulfurization and denitrification reaction tower;

[0044] The pipeline connecting the desulfurization and denitrification reaction tower and the emission chimney is equipped with NOx sensors, SO2 sensors and pressure sensors.

[0045] Preferred: The activated alumina has a particle size of 3-8 mm, a pore volume greater than 0.4 ml / g, and a specific surface area greater than 300 m². 2 / g, water absorption rate greater than 47%, compressive strength greater than 150N, alumina content greater than 90%.

[0046] Activated alumina, primarily composed of γ-Al₂O₃, is a porous, highly dispersed spherical solid material with a large surface area. Its microporous surface possesses the characteristics required for catalysis, exhibiting good adsorption performance, surface activity, and excellent thermal stability. It serves as an adsorbent, catalyst, and catalyst support in chemical reactions. The spherical activated alumina used in this invention consists of white, spherical, porous particles with uniform particle size, smooth surface, high mechanical strength, and strong hygroscopicity; it retains its original shape without swelling or cracking after absorbing water. This activated alumina catalyst can utilize existing technologies, such as those from Tianjin Chilong and Jiangxi Xintao companies.

[0047] Activated alumina, as a highly efficient desiccant and catalyst, becomes more reactive in high-temperature and aqueous environments. Upon contact with water, it combines with water, and the transfer of charged ions at the liquid-solid interface causes the surface of γ-Al2O3 to hydrate and form alumina hydrate, which more easily absorbs sulfur dioxide and nitrogen oxides in flue gas. Under the action of catalysis, sulfur dioxide and nitric oxide undergo redox reactions to generate nitrogen dioxide and sulfur trioxide.

[0048] This utility model also discloses a dry integrated flue gas treatment method for flue gas desulfurization and denitrification, which uses the above-mentioned system for treatment and includes the following steps:

[0049] Flue gas reacts in the desulfurization and denitrification reaction tower to produce sulfuric acid, nitric acid, and sulfurous acid, which are then saturated by the catalyst.

[0050] After being washed by a washing and dehydration unit and dehydrated by a dehydrator, the saturated catalyst is sent to the upper part of the desulfurization and denitrification reaction tower for use.

[0051] The washing liquid in the washing and dewatering unit is treated by the neutralization, oxidation, desulfurization and denitrification section to obtain a usable resource.

[0052] Preferably, the temperature of the raw flue gas is 80-150℃.

[0053] Based on the above technical solution, the dry integrated flue gas treatment system for flue gas desulfurization and denitrification provided by this utility model is suitable for use in the low temperature range, with an applicable temperature between 80-150℃. At lower temperatures, activated alumina will adsorb a large amount of water, resulting in hydration. Hydrated alumina will precipitate on the surface of activated alumina, blocking the pores, covering the active sites, and reducing the utilization rate of alumina. At higher temperatures, the adsorption effect of activated alumina decreases, reducing the amount of sulfur dioxide and nitrogen oxides entering the pores. Furthermore, the sulfuric acid generated by the catalytic reaction after adsorption is easily reacted with alumina, causing irreversible deactivation of activated alumina.

[0054] Preferably, the dust concentration at the electrostatic precipitator outlet is 20 mg / m³. 3 The following steps ensure that a large amount of dust does not adhere to the catalyst surface, thus affecting the normal use of the catalyst.

[0055] Preferably, the activated alumina stockpile is placed in the moving bed, and the height of the activated alumina stockpile is 2-3 times the width of the desulfurization and denitrification reaction tower.

[0056] The lower half of the desulfurization and denitrification reaction tower is used for desulfurization and denitrification, the top part is used for catalyst drying, and the middle part is used for sealing. The height of the catalyst layer is 2-3 times the width of the reaction tower. The inlet and outlet gas distribution holes of the raw flue gas are made of multi-layer stainless steel wire mesh and are reinforced with support.

[0057] Preferably, the flue gas velocity inside the desulfurization and denitrification reaction tower is 0.5-1m / s, the width of the moving bed is 3-4m, and the inlet and outlet pressure difference of the desulfurization and denitrification reaction tower is within 3KPa.

[0058] Based on the above technical solution, the flue gas velocity within the control device is maintained at 0.5-1 m / s, the moving bed width at 3-4 m, and the inlet / outlet pressure difference at 3 kPa. Simultaneously, the raw flue gas temperature is maintained at 80-150℃, ensuring sufficient contact time and area for sulfur dioxide and nitrogen oxides on the catalyst surface, guaranteeing complete adsorption of sulfur dioxide and nitrogen oxides by the catalyst. Furthermore, the reaction tower can be composed of several independent units arranged in parallel, facilitating uniform flue gas distribution and simplifying catalyst installation and disassembly.

[0059] Specifically, the washing and dehydration unit mainly includes a washing tank, a dehydrator, and an outlet pump. Nearly activated catalyst in the reaction tower is sent to the washing tank via a star valve. The washing tank is filled with industrial water. Under the action of the agitator in the washing tank, dust on the catalyst surface is removed, and oxidation products such as sulfuric acid, sulfurous acid, and nitric acid within the catalyst are dissolved in the washing liquid. Then, the catalyst is sent to the belt dehydrator via a slag remover for further rinsing and surface dehydration. The solution in the washing tank is acidic, so acid corrosion prevention treatment is necessary. Existing technology can be used for the washing and dehydration unit.

[0060] Specifically, the neutralization oxidation tower includes a tower body, a demister, a spray layer, a circulating pump, a discharge pump, a mixer, an oxidation blower and air distribution pipes, a filter, and an evaporator. In the mixer, the catalyst washing liquid and limestone slurry are thoroughly mixed and reacted, controlling the slurry in the neutralization tower to be slightly acidic. The neutralization oxidation tower also employs countercurrent gas-liquid contact to ensure sufficient contact time and area between the air supplied by the oxidation blower and the sprayed slurry, oxidizing sulfite ions to sulfate ions. The oxidized slurry mainly consists of calcium sulfate, which is removed from the slurry through a filter. The filtered clear liquid is used for washing tanks or preparing limestone slurry. When the nitrate concentration in the clear liquid is high, it enters the evaporator for crystallization. The neutralization oxidation tower can utilize existing technology.

[0061] Furthermore, the inlet of the electrostatic precipitator is connected to the kiln exhaust gas, and the outlet is connected to the inlet of the induced draft fan. The outlet of the induced draft fan is connected to the inlet of the desulfurization and denitrification reaction tower, and the outlet of the desulfurization and denitrification reaction tower is connected to the flue. Sulfur dioxide and nitrogen oxide analyzers, as well as temperature, pressure, and air volume meters are installed on the inlet and outlet flues of the desulfurization and denitrification reaction tower.

[0062] Furthermore, the bottom outlet of the desulfurization and denitrification reaction tower is connected to the washing tank, the liquid outlet pump of the washing tank is connected to the liquid inlet of the neutralization oxidation tower, the washing tank is connected to the dewatering machine through the slag removal machine, and the dewatering machine is connected to the top silo of the desulfurization and denitrification reaction tower through the belt.

[0063] Furthermore, the slurry inlet of the neutralization oxidation tower is connected to the pipeline mixer, the outlet of the oxidation blower is connected to the neutralization oxidation tower, the bottom outlet pump of the oxidation tower is connected to the filter through a pipeline, and the outlet of the filter is connected to the circulating spray of the oxidation tower or to the evaporation crystallization device.

[0064] The beneficial effects of this utility model are as follows:

[0065] Compared with traditional NH3-SCR ammonia injection denitrification, the working principle of this invention does not require ammonia as a reducing agent for the denitrification reaction. Furthermore, the catalyst is inexpensive, contains no heavy metals, resulting in significant cost savings. The reaction temperature is also lower, and the denitrification reaction occurs after flue gas dust removal, reducing the impact of dust on the catalyst. The generated sulfuric acid can be neutralized with various alkaline substances, allowing for the selection of appropriate neutralizing agents based on local conditions. Compared with traditional wet limestone desulfurization, it has lower energy consumption, a simpler structure, and lower water consumption.

[0066] The catalyst used in this invention is activated alumina, which has good catalytic performance, low price, simple regeneration method, and can be reused.

[0067] This utility model's dry integrated flue gas treatment system has a simple structure, is easy to manufacture, is safe and reliable to use, and is easy to implement and promote. It can shorten the process and reduce investment costs, and has certain practical application prospects. Attached Figure Description

[0068] Figure 1 This is a schematic diagram of the dry integrated flue gas treatment system for flue gas desulfurization and denitrification provided by this utility model.

[0069] Figure 2 This is a schematic diagram of the catalyst packing layer.

[0070] Appendix Figure 1 The structures represented by each label are listed below:

[0071] 1. Electrostatic precipitator; 2. Exhaust fan; 3. Desulfurization and denitrification reaction tower; 4. Washing and dewatering device; 5. Limestone pipeline mixer; 6. Neutralization and oxidation tower; 7. Gypsum filter; 8. Nitrate evaporator; 9. Dewatering machine. Detailed Implementation

[0072] The principles and features of this utility model are described below. The embodiments given are only used to explain this utility model and are not intended to limit the scope of this utility model.

[0073] Unless otherwise specified, the testing methods used in the embodiments of this utility model are all conventional methods; unless otherwise specified, the materials and reagents used are commercially available.

[0074] The activated alumina catalysts used are those from Tianjin Chilong and Jiangxi Xintao companies.

[0075] Example 1

[0076] like Figure 1 As shown, the dry integrated flue gas treatment system for flue gas desulfurization and denitrification includes an electrostatic precipitator 1, an induced draft fan 2, and a desulfurization and denitrification reaction tower 3 connected in sequence. The bottom end of the desulfurization and denitrification reaction tower 3 has a discharge port, which is connected to a washing and dewatering device 4. The washing and dewatering device 4 is connected to the neutralization and oxidation desulfurization and denitrification section. An active alumina stockpile is set inside the desulfurization and denitrification reaction tower 3.

[0077] In the desulfurization and denitrification reaction tower: The reaction tower adopts a moving bed form with a built-in catalyst. The catalyst is made into a spherical shape. After the raw flue gas enters the moving bed, the sulfur dioxide and nitrogen monoxide in the flue gas are simultaneously adsorbed by the catalyst. Under the action of the catalyst, an oxidation-reduction reaction occurs to generate nitrogen dioxide and sulfur trioxide. These react with the water adsorbed by the catalyst to generate sulfuric acid and nitric acid. At the same time, the remaining sulfur dioxide in the flue gas is also absorbed by the catalyst to generate sulfurous acid.

[0078] In the washing and dehydration unit: after the catalyst adsorbing sulfuric acid and sulfurous acid is close to exhaust saturation, the sulfuric acid is removed after washing and dehydration, and then sent back to the reaction tower for denitrification and desulfurization reaction.

[0079] In the neutralization and oxidation desulfurization and denitrification section: the sulfuric acid and sulfurous acid absorbed by the catalyst are washed and then enter the solution, and then neutralized by alkaline solution. Since the solution contains a certain amount of sulfite, the sulfite is completely oxidized by the oxidation tower, and then filtered. After liquid-solid separation, it is reused.

[0080] Example 2

[0081] Based on Example 1, such as Figure 1 As shown:

[0082] Electrostatic precipitator 1 is connected to the original flue gas inlet pipe;

[0083] A gap is left between the top of the activated alumina stockpile and the top plate of the desulfurization and denitrification reaction tower 3. An air inlet and an air outlet are respectively installed on both sides of the bottom of the desulfurization and denitrification reaction tower 3. A return air outlet is installed at the top of the desulfurization and denitrification reaction tower 3. The air outlet is connected to the return air outlet, and the air inlet is connected to the induced draft fan 2. Multiple layers of stainless steel wire mesh are installed at both the air inlet and the air outlet. The desulfurization and denitrification reaction tower 3 is connected to the exhaust chimney. The top of the desulfurization and denitrification reaction tower 3 is connected to the dehydrator 9.

[0084] The washing and dewatering device 4 is equipped with a stirring device. In conjunction with the washing and dewatering device 4, a slag removal device is provided to transfer the catalyst residue therein to the dewatering machine 9.

[0085] The neutralization and oxidation desulfurization and denitrification section includes a limestone pipeline mixer 5, a neutralization oxidation tower 6, a gypsum filter 7, and a nitrate evaporator 8, which are connected in sequence. The neutralization oxidation tower 6 is equipped with an oxidation fan;

[0086] The gypsum filter 7 has a clear liquid outlet. The clear liquid outlet is connected to the washing and dewatering device 4 and the limestone pipeline.

[0087] The principle of catalyst stacking in desulfurization and denitrification reaction tower 3 is as follows: Figure 2 As shown.

[0088] Example 3

[0089] like Figure 1 As shown, based on Example 2, NOx sensors, SO2 sensors, and pressure sensors are installed on the pipeline connecting the induced draft fan 2 and the desulfurization and denitrification reaction tower 3. NOx sensors, SO2 sensors, and pressure sensors are also installed on the pipeline connecting the desulfurization and denitrification reaction tower 3 and the exhaust chimney.

[0090] Example 1

[0091] 1. Before the system is ready to start, a certain level of catalyst is delivered to the reaction tower, water at an appropriate level is injected into the washing tank, and slurry at an appropriate level is injected into the neutralization oxidation tower and circulation begins.

[0092] 2. After the induced draft fan is started, the flue gas is discharged through the bypass. When the flue gas temperature is normal and the electrostatic precipitator is in normal operation, the flue gas is introduced into the reaction tower. The amount of catalyst entering and leaving the reaction tower is adjusted according to the concentration of sulfur dioxide and nitrogen oxides at the outlet to maintain a certain material level.

[0093] 3. The reaction tower uses a star valve to control the flow of degraded catalyst into a washing tank. A mixer thoroughly washes the catalyst with water, removing sulfuric acid, sulfurous acid, and nitric acid products. The pH of the solution in the washing tank is controlled between 3 and 4. When the pH begins to decrease, the bottom pump is activated to deliver slurry to the neutralization oxidation tower, while industrial water is added to the washing tank. After washing in the tank, the catalyst is sent to a dewatering machine via a slag remover. After preliminary dewatering, the catalyst is returned to the top of the reaction tower, covering the original catalyst surface. Waste heat from the flue gas is used to dry the top of the catalyst layer.

[0094] 4. The acidic solution in the washing tank is sent to the neutralization tower through the discharge pump. During this process, it is fully mixed with the limestone slurry through the pipeline mixer and then enters the oxidation tower for neutralization reaction. At the same time, the oxidation blower is started to oxidize the sulfite and nitrite in the slurry and control the pH of the slurry at 5-6. Simultaneously, the discharge pump is started to send the slurry to the gypsum filter for liquid-solid separation. The filtrate is reused to prepare limestone slurry.

[0095] 5. When the nitrate concentration in the slurry is high (30%), the filtrate from the gypsum filter is fed into a nitrate evaporator for crystallization and evaporation. The main component after evaporation, calcium nitrate, can be used as fertilizer, and the water is returned to the washing tank for reuse.

[0096] The process parameters are as follows:

[0097] The original flue gas temperature was approximately 115℃.

[0098] The dust concentration at the outlet of the electrostatic precipitator is 20 mg / m³. 3 the following.

[0099] The activated alumina stockpile is placed in the moving bed, and the height of the activated alumina stockpile is about 2.5 times the width of the desulfurization and denitrification reaction tower, which can prevent flue gas from flowing inside the tower.

[0100] The flue gas velocity inside the desulfurization and denitrification reaction tower is about 0.75 m / s, the width of the moving bed is 3.5 m, and the pressure difference between the inlet and outlet of the desulfurization and denitrification reaction tower is within 3 kPa.

[0101] Original flue gas composition: 200 mg nitric oxide, 3000 mg sulfur dioxide.

[0102] Emissions composition: Nitrogen monoxide <20mg, sulfur dioxide <30mg.

[0103] The main component of the nitrate evaporator is calcium nitrate, along with small amounts of other calcium salts.

[0104] As can be seen from the data in the embodiments, the flue gas treatment system of this utility model can effectively remove sulfur dioxide and nitrogen oxides from flue gas, and can also remove harmful gases such as hydrogen chloride and hydrogen fluoride, with a removal rate of over 99%, thereby reducing the risk of environmental damage from flue gas emissions. The flue gas treatment system of this utility model has a simple structure, is easy to manufacture, and is safe and reliable to use. It can shorten the process, reduce investment costs, has low energy and water consumption, and is easy to implement and promote, showing promising practical application prospects.

[0105] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A dry integrated flue gas treatment system for flue gas desulfurization and denitrification, characterized in that: At least comprising electric dust collector (1), induced draft fan (2) and desulfurization and denitrification reaction tower (3) arranged in sequence, the bottom end of the desulfurization and denitrification reaction tower (3) is provided with discharge port, the discharge port is communicated with washing and dewatering device (4), the washing and dewatering device (4) is communicated with neutralization and oxidation desulfurization and denitrification section, and active alumina stockpile layer is arranged in the desulfurization and denitrification reaction tower (3).

2. The dry integrated flue gas desulfurization and denitrification system of claim 1, wherein, The system further comprises: dewatering machine (9) communicated with the top of the desulfurization and denitrification reaction tower (3); and the catalyst residue in the washing and dewatering device (4) is sent to the dewatering machine (9) by the residue salvaging device.

3. The dry integrated flue gas desulfurization and denitrification system of flue gas according to claim 2, characterized in that: The top of the active alumina stockpile layer and the top plate of the desulfurization and denitrification reaction tower (3) are left with a gap, the bottom of the desulfurization and denitrification reaction tower (3) is provided with gas inlet and gas outlet respectively, the top of the desulfurization and denitrification reaction tower (3) is provided with gas return port, the gas outlet is communicated with the gas return port, and the gas inlet is communicated with the induced draft fan (2); the gas inlet and the gas outlet are respectively provided with multiple layers of stainless steel wire mesh.

4. The dry integrated flue gas desulfurization and denitrification system of flue gas according to claim 3, characterized in that: The neutralization and oxidation desulfurization and denitrification section comprises limestone pipeline mixer (5), neutralization and oxidation tower (6), gypsum filter (7) and nitrate evaporator (8) arranged in sequence.

5. The dry-process integrated flue gas desulfurization and denitrification system according to claim 4, characterized in that: the gypsum filter (7) is provided with clear liquid outlet; the clear liquid outlet is communicated with the washing and dewatering device (4) or the limestone pipeline mixer.

6. The dry-process integrated flue gas desulfurization and denitrification system according to claim 5, characterized in that: the washing and dewatering device (4) is provided with stirring device; the neutralization and oxidation tower (6) is provided with oxidation fan.

7. The dry-process integrated flue gas desulfurization and denitrification system according to claim 6, characterized in that: the electric dust collector (1) is communicated with raw flue gas inlet pipe; the desulfurization and denitrification reaction tower (3) is communicated with discharge chimney.

8. The dry-process integrated flue gas desulfurization and denitrification system according to claim 7, characterized in that: the pipeline between the induced draft fan (2) and the desulfurization and denitrification reaction tower (3) is provided with NOx sensor, SO2 sensor and pressure sensor; the pipeline between the desulfurization and denitrification reaction tower (3) and the discharge chimney is provided with NOx sensor, SO2 sensor and pressure sensor.

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