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

Abstract

The invention belongs to the technical field of flue gas purification, and particularly relates to a dry-process integrated flue gas treatment system and method 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. And the desulfurization and denitrification reaction tower is filled with an activated aluminum oxide stockpile. According to the method, activated aluminum oxide is adopted as a catalyst, and sulfur dioxide and nitrogen oxide are integrally removed by a dry method by using the catalyst. The catalyst has good performance, is simple in regeneration mode and can be repeatedly used.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas purification, and in particular relates to a dry integrated flue gas treatment system and method for flue gas desulfurization and denitrification. Background Art

[0002] With the rapid development of industrialization, the problem of air pollution in the process of using coal energy for power generation has gradually become prominent. For example, the flue gas produced in kilns such as steel, cement, building materials, glass, and metallurgy contains a large amount of sulfur dioxide, nitrogen oxides, smoke and other pollutants, which cause great harm to human health and the ecological environment. Excessive nitrogen oxide and sulfur dioxide emissions not only cause serious damage to the human respiratory system, but also cause acid rain, photochemical pollution, ozone layer depletion and other environmental problems.

[0003] At present, the most mature and efficient denitrification process in China is the selective catalytic reduction denitrification process. However, due to the difficulty in controlling the activity of the catalyst and the large amount of ammonia used in the production process, the process application cost is relatively high. Desulfurization mostly adopts wet desulfurization technology, and the desulfurization material selected is usually limestone slurry agent. The desulfurization efficiency is high, but the energy consumption is large, the water consumption is high, and the desulfurization product is difficult to handle. Denitrification and desulfurization of flue gas are two important control indicators. At present, there is no mature integrated desulfurization and denitrification equipment used in the production field. Summary of the invention

[0004] In order to solve the deficiencies of the prior art, the present invention provides a dry integrated flue gas treatment system and method for flue gas desulfurization and denitrification. The present invention uses activated alumina as a catalyst to remove sulfur dioxide and nitrogen oxides in an integrated dry process. The catalyst has good performance, a simple regeneration method, and can be reused.

[0005] The technical solution provided by the present invention is as follows:

[0006] A dry integrated flue gas treatment system for flue gas desulfurization and denitrification comprises an electrostatic precipitator, an induced draft fan and a desulfurization and denitrification reaction tower which are connected in sequence. The bottom end of the desulfurization and denitrification reaction tower is provided with a discharge port which is connected to a washing and dehydration device which is connected to a neutralization oxidation desulfurization and denitrification section. The desulfurization and denitrification reaction tower is filled with activated alumina.

[0007] In the above technical solution:

[0008] After the dust is removed by the electrostatic precipitator, the original flue gas enters the integrated denitrification and desulfurization reactor. The nitrogen monoxide in the flue gas reacts with the oxygen and sulfur dioxide in the flue gas under the action of the catalyst to generate sulfur trioxide and nitrogen dioxide. Since the catalyst has strong water absorption, sulfur trioxide, nitrogen dioxide and excess sulfur dioxide are also adsorbed by the catalyst to generate sulfuric acid, nitric acid and sulfurous acid. After the catalyst adsorbs sulfuric acid, nitric acid and sulfurous acid, it is saturated and then washed and dried and sent to the reaction tower for denitrification and desulfurization. The washed acid solution is neutralized, oxidized and filtered for resource utilization again. This method mainly uses the catalyst to stimulate the oxidizing properties of sulfur dioxide and nitrogen monoxide, oxidizes sulfur dioxide into sulfur trioxide, and oxidizes nitrogen monoxide into nitrogen dioxide, thereby converting the difficult-to-remove nitrogen monoxide in the flue gas into nitrogen dioxide, which is adsorbed by the catalyst and then analyzed and removed.

[0009] The main reaction equation in the denitrification and desulfurization reaction tower is:

[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 in the denitrification 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] The main reaction equation in the neutralization oxidation tower is:

[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 further comprises:

[0029] A dehydrator, the dehydrator being connected to the top of the desulfurization and denitration reaction tower;

[0030] And the catalyst residue in the washing and dehydrating device is sent to the residue collecting device of the dehydrator.

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

[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] Further:

[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] Specific:

[0037] The washing and dehydrating device is provided with a stirring device;

[0038] The neutralization oxidation tower is provided with an oxidation blower.

[0039] Specific:

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

[0041] The desulfurization and denitration reaction tower is connected to an emission chimney.

[0042] Further:

[0043] A NOx sensor, a SO2 sensor and a pressure sensor are arranged on the pipeline connecting the induced draft fan and the desulfurization and denitration reaction tower;

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

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

[0046] The main component of activated alumina, γ-Al2O3, is a porous, highly dispersed spherical solid material with a large surface area. Its microporous surface has the characteristics required for catalysis, good adsorption performance, surface activity, excellent thermal stability, etc. It is used as an adsorbent and a catalyst and catalyst carrier for chemical reactions. The spherical activated alumina used in the present invention is a white spherical porous particle with uniform particle size, smooth surface, high mechanical strength, strong hygroscopicity, and does not swell or crack after absorbing water and remains in its original state. The activated alumina catalyst can adopt existing technology, such as the activated alumina catalysts of Tianjin Chilong and Jiangxi Xintao Company brands.

[0047] Activated alumina is a highly efficient desiccant and catalyst. In high temperature and water environment, γ-Al2O3 becomes more active and combines with water when it comes into contact with water. Charged ion transfer occurs at the liquid-solid interface, causing the surface of γ-Al2O3 to hydrate to form alumina hydrate, which is more likely to absorb sulfur dioxide and nitrogen oxides in flue gas. Under the action of the catalyst, sulfur dioxide and nitrogen monoxide undergo redox reactions to generate nitrogen dioxide and sulfur trioxide.

[0048] The present invention also provides a dry integrated flue gas treatment method for flue gas desulfurization and denitrification, which adopts the above system for treatment. The treatment method comprises the following steps:

[0049] The flue gas reacts in the desulfurization and denitrification reaction tower to produce sulfuric acid, nitric acid, and sulfurous acid, which are saturated by the catalyst adsorption;

[0050] The adsorption saturated catalyst is washed by the washing and dehydration device and dehydrated by the dehydrator, and then sent to the upper part of the desulfurization and denitration reaction tower for use;

[0051] The washing liquid in the washing and dehydration device is treated in the neutralization, oxidation, desulfurization and denitrification sections to obtain usable resources.

[0052] Preferably, the original flue gas temperature is 80-150°C.

[0053] Based on the above technical scheme, the dry integrated flue gas treatment system for flue gas desulfurization and denitrification provided by the present invention is suitable for use in the low temperature range, and the applicable temperature is between 80-150°C. When the temperature is low, the activated alumina will adsorb a large amount of water, resulting in hydration, and hydrated alumina will precipitate on the surface of the activated alumina, blocking the pores, covering the active sites, and reducing the utilization rate of alumina. When the temperature is high, the adsorption effect of the activated alumina decreases, and the amount of sulfur dioxide and nitrogen oxides entering the pores is reduced. In addition, the sulfuric acid generated by the catalytic reaction after adsorption is easy to react with alumina, resulting in irreversible deactivation of the activated alumina.

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

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

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

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

[0058] Based on the above technical solution, the flue gas velocity in the control device is controlled at 0.5-1m / s, the moving bed width is 3-4m, and the inlet and outlet pressure difference is controlled within 3KPa. At the same time, the original flue gas temperature is 80-150℃, which is conducive to ensuring that sulfur dioxide and nitrogen oxides have sufficient contact time and sufficient contact area on the catalyst surface, ensuring that sulfur dioxide and nitrogen oxides can be completely adsorbed by the catalyst. At the same time. The reaction tower can be composed of several independent units in parallel, which is convenient for uniform distribution of flue gas and is conducive to the installation and removal of catalysts.

[0059] Specifically, the washing and dehydration device mainly includes a washing tank, a dehydrator, and a liquid outlet pump. The catalyst in the reaction tower that is close to being effective is sent to the washing tank through a star valve. The washing tank is filled with industrial water. The catalyst is fully stirred under the action of the washing tank agitator to remove dust on the catalyst surface. At the same time, the oxidation products such as sulfuric acid, sulfurous acid, and nitric acid in the catalyst are dissolved in the washing liquid. Then, the catalyst is sent to the belt dehydrator through a slag remover to rinse the catalyst again and dehydrate the surface. The solution in the washing tank is acidic, so it should be treated to prevent acid corrosion. The washing and dehydration device can adopt existing technology.

[0060] Specifically, the neutralization oxidation tower includes a tower body, a demister, a spray layer, a circulation pump, a discharge pump, a mixer, an oxidation fan and an air distribution pipe, a filter, and an evaporator. In the mixer, the catalyst washing liquid and the limestone slurry are fully mixed and reacted to control the acidity of the slurry in the neutralization tower. The neutralization oxidation tower also adopts gas-liquid countercurrent contact to ensure that the air sent in by the oxidation fan and the sprayed slurry have sufficient contact time and area to oxidize sulfite into sulfate. The main solid of the oxidized slurry is calcium sulfate, which is removed from the slurry by a filter. The filtered clear liquid is used for the configuration of the washing tank or limestone slurry. When the concentration of nitrate in the clear night is high, it enters the evaporator for crystallization. The neutralization oxidation tower can adopt existing technology.

[0061] Furthermore, the inlet of the electrostatic precipitator is connected to the kiln exhaust gas, 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, the outlet of the desulfurization and denitrification reaction tower is connected to the chimney, and 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 discharge port of the desulfurization and denitration reaction tower is connected to the washing tank, the washing tank outlet pump is connected to the neutralization oxidation tower inlet, the washing tank is connected to the dehydrator through the slag remover, and the dehydrator is connected to the top silo of the desulfurization and denitration reaction tower through a belt.

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

[0064] The beneficial effects of the present invention are as follows:

[0065] Compared with the traditional NH3-SCR ammonia spray denitrification, in the working principle of the present invention, the denitrification reaction does not require ammonia as a reducing agent, and the catalyst is relatively low in price, does not contain heavy metals, and saves a lot of costs. The reaction temperature is relatively low, and the denitrification reaction is carried out after the flue gas dust removal to reduce the impact of dust on the catalyst. The generated sulfuric acid can be neutralized with various alkaline substances, and appropriate neutralizing substances can be selected according to local actual conditions. Compared with the traditional wet limestone desulfurization, it has lower energy consumption, simpler structure, and less water consumption.

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

[0067] The dry integrated flue gas treatment system of the present invention has a simple structure, is easy to manufacture, is safe and reliable to use, and is easy to implement, promote and apply. It can shorten the process, reduce investment costs, and has certain practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a structural schematic diagram of the dry integrated flue gas treatment system for flue gas desulfurization and denitrification provided by the present invention.

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

[0070] Attached Figure 1 The structures represented by the labels are listed below:

[0071] 1. Electrostatic precipitator; 2. Induced draft fan; 3. Desulfurization and denitrification reaction tower; 4. Washing and dehydration device; 5. Limestone pipeline mixer; 6. Neutralization and oxidation tower; 7. Gypsum filter; 8. Nitrate evaporator; 9. Dehydrator. DETAILED DESCRIPTION

[0072] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0073] Unless otherwise specified, the test methods used in the embodiments of the present invention are all conventional methods; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0074] The activated alumina catalysts used are those of the brands of Tianjin Chilong and Jiangxi Xintao.

[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 which are connected in sequence. The bottom end of the desulfurization and denitrification reaction tower 3 is provided with a discharge port, the discharge port is connected to a washing and dehydration device 4, the washing and dehydration device 4 is connected to a neutralization oxidation desulfurization and denitrification section, and the desulfurization and denitrification reaction tower 3 is filled with activated alumina pile.

[0077] In the desulfurization and denitrification reaction tower: the reaction tower adopts a moving bed form, with a built-in catalyst, and the catalyst is made into a spherical shape. After the original flue gas enters the moving bed, the sulfur dioxide and nitrogen monoxide in the flue gas are adsorbed by the catalyst at the same time, and an oxidation-reduction reaction occurs under the action of the catalyst to generate nitrogen dioxide and sulfur trioxide, which react with the moisture 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 device: when the catalyst that absorbs sulfuric acid and sulfurous acid is close to failure and saturation, the sulfuric acid is removed after washing and dehydration, and then sent to the reaction tower again for denitration and desulfurization reaction;

[0079] In the neutralization oxidation desulfurization and denitrification section: the sulfuric acid and sulfurous acid absorbed by the catalyst enter the solution after washing, and then the neutralization reaction is carried out by alkaline solution. Because the solution contains a certain amount of sulfite, the sulfite is completely oxidized by the oxidation tower, and then filtered and reused after liquid-solid classification.

[0080] Example 2

[0081] On the basis of Example 1, Figure 1 As shown:

[0082] The electrostatic precipitator 1 is connected to the original flue gas pipe;

[0083] There is a gap between the top of the activated alumina pile and the top plate of the desulfurization and denitration reaction tower 3. The two sides of the bottom of the desulfurization and denitration reaction tower 3 are respectively provided with an air inlet and an air outlet. The top of the desulfurization and denitration reaction tower 3 is provided with an air return port, the air outlet is connected to the air return port, and the air inlet is connected to the induced draft fan 2; the air inlet and the air outlet are respectively provided with multiple layers of stainless steel wire mesh. The desulfurization and denitration reaction tower 3 is connected to the emission chimney. The top of the desulfurization and denitration reaction tower 3 is connected to the dehydrator 9;

[0084] The washing and dehydrating device 4 is provided with a stirring device. In conjunction with the washing and dehydrating device 4, a slag collecting device is provided to send the catalyst slag therein to the dehydrator 9;

[0085] The neutralization 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 has an oxidation fan;

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

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

[0088] Example 3

[0089] like Figure 1 As shown, on the basis of Example 2, a NOx sensor, a SO2 sensor and a pressure sensor are installed in the pipeline connecting the induced draft fan 2 and the desulfurization and denitration reaction tower 3. A NOx sensor, a SO2 sensor and a pressure sensor are installed in the pipeline connecting the desulfurization and denitration reaction tower 3 and the emission chimney.

[0090] Effect Example 1

[0091] 1. Before the system is started, 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 and oxidation tower to start circulation.

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

[0093] 3. The reaction tower controls the spent catalyst to be sent to the washing tank through the star valve, and the water and catalyst are fully cleaned through the mixer to remove the products of sulfuric acid, sulfurous acid and nitric acid in the catalyst. The pH of the solution in the washing tank is controlled between 3-4. When the pH begins to decrease, the bottom outlet pump is started to transport the slurry to the neutralization oxidation tower, and industrial water is added to the washing tank. After cleaning in the washing tank, the catalyst is sent to the dehydrator through the slag picker. After preliminary dehydration, the catalyst is returned to the upper part of the reaction tower and covered on the surface of the original catalyst. The catalyst on the top of the catalyst layer is dried using the waste heat of the flue gas.

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

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

[0096] The process parameters are as follows:

[0097] The original flue gas temperature is about 115℃.

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

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

[0100] The flue gas flow rate in the desulfurization and denitrification reaction tower is about 0.75m / s, the width of the moving bed is 3.5m, and the inlet and outlet pressure difference of the desulfurization and denitrification reaction tower is within 3KPa.

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

[0102] Exhaust gas components: nitrogen monoxide <20mg, sulfur dioxide <30mg.

[0103] Ingredients in nitrate evaporator: The main component is calcium nitrate, and a small amount of other calcium salts.

[0104] Combined with the data of the embodiment, it can be seen that the flue gas treatment system of the embodiment of the present invention can effectively remove sulfur dioxide and nitrogen oxides in the flue gas, and can also remove harmful gases such as hydrogen chloride and hydrogen fluoride in the flue gas, with a removal rate of more than 99%, thereby reducing the risk of flue gas emissions harming the environment. The flue gas treatment system of the embodiment of the present invention has a simple structure, is easy to manufacture, is safe and reliable to use, can shorten the process, reduce investment costs, has low system energy and water consumption, is easy to implement and promote, and has certain practical application prospects.

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

Claims

1. A dry integrated flue gas treatment system for flue gas desulfurization and denitrification, characterized in that: The invention comprises at least an electrostatic precipitator (1), an induced draft fan (2) and a desulfurization and denitration reaction tower (3) which are connected in sequence. The bottom end of the desulfurization and denitration reaction tower (3) has a discharge port, the discharge port is connected to a washing and dehydration device (4), the washing and dehydration device (4) is connected to a neutralization oxidation desulfurization and denitration section, and the desulfurization and denitration reaction tower (3) is filled with activated alumina.

2. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to claim 1 is characterized in that: The system further comprises: A dehydrator (9), the dehydrator (9) being connected to the top of the desulfurization and denitration reaction tower (3); And a slag collecting device for sending the catalyst slag in the washing and dehydrating device (4) to the dehydrator (9).

3. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to claim 2 is characterized in that: A gap is left between the top of the activated alumina pile and the top plate of the desulfurization and denitration reaction tower (3); an air inlet and an air outlet are respectively arranged on both sides of the bottom of the desulfurization and denitration reaction tower (3); an air return port is arranged on the top of the desulfurization and denitration reaction tower (3); the air outlet is connected to the air return port, and the air inlet is connected to the induced draft fan (2); and the air inlet and the air outlet are respectively provided with multiple layers of stainless steel wire mesh.

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

5. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to claim 4 is characterized in that: The gypsum filter (7) has a clear liquid outlet; The clear liquid outlet is connected to the washing and dehydration device (4) or the limestone pipeline.

6. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to claim 5 is characterized in that: The washing and dehydrating device (4) is provided with a stirring device; The neutralization oxidation tower (6) is provided with an oxidation blower.

7. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to claim 6 is characterized in that: The electrostatic precipitator (1) is connected to the original flue gas inlet pipe; The desulfurization and denitrification reaction tower (3) is connected to an emission chimney.

8. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to claim 7 is characterized in that: A NOx sensor, a SO2 sensor and a pressure sensor are arranged in a pipeline connecting the induced draft fan (2) and the desulfurization and denitration reaction tower (3); A NOx sensor, a SO2 sensor and a pressure sensor are arranged on the pipeline connecting the desulfurization and denitrification reaction tower (3) and the emission chimney.

9. The dry integrated flue gas treatment system for flue gas desulfurization and denitrification according to any one of claims 1 to 8, characterized in that: The particle size of activated alumina is 3-8mm, the pore volume is greater than 0.4ml / g, and the specific surface area is greater than 300m 2 / g, water absorption greater than 47%, compressive strength greater than 150N, and alumina content greater than 90%.

10. A dry integrated flue gas treatment method for flue gas desulfurization and denitrification, characterized in that: The system according to any one of claims 1 to 9 is used for processing, and the processing method comprises the following steps: The flue gas reacts in the desulfurization and denitrification reaction tower to produce sulfuric acid, nitric acid, and sulfurous acid, which are saturated by the catalyst adsorption; The adsorption saturated catalyst is washed by the washing and dehydration device and dehydrated by the dehydrator, and then sent to the upper part of the desulfurization and denitration reaction tower for use; The washing liquid in the washing and dehydration device is treated in the neutralization, oxidation, desulfurization and denitrification process to obtain usable resources; in: The original flue gas temperature is 80-150℃; The dust concentration at the outlet of the electrostatic precipitator is 20mg / m 3 the following; The activated alumina pile is filled in the moving bed, and the height of the activated alumina pile is 2-3 times the width of the desulfurization and denitrification reaction tower; The flue gas flow rate in 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.

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