Flue gas denitration and decarbonization system

Abstract

According to the flue gas denitration and decarburization system, raw flue gas and hot air are directly mixed to increase the temperature of the raw flue gas, so that the flue gas denitration and decarburization system is not influenced by the temperature of the raw flue gas, the amount of the mixed hot air can be adjusted according to requirements, the flue gas temperature is ensured to reach the optimal denitration and decarburization range, and the adaptability of the whole system to the raw flue gas is improved; the desulfurization and denitrification efficiency is further ensured; meanwhile, the high-low temperature fluid mixer is arranged on the raw flue gas conveying pipeline and used for mixing the raw flue gas and the hot air, the uniformity of the mixed gas is improved, and therefore the uniformity and stability of the temperature of the mixed gas entering the denitration and decarbonization chamber are guaranteed, and the denitration and decarbonization effect is effectively improved.

Description

Technical Field

[0001] This utility model relates to a flue gas purification system, specifically a denitrification and decarbonization system for flue gas treatment, and belongs to the technical field of flue gas purification devices. Background Technology

[0002] With the advancement of industrialization and the continuous expansion of production capacity, taking the steel industry as an example, the problem of pollutants emitted during steel production has become increasingly serious. In particular, the emissions of nitrogen oxides (NOx) and carbon monoxide (CO), two representative pollutants, have become significant factors affecting environmental quality and human health. NOx is one of the main precursors to acid rain and photochemical smog, directly impacting air quality and causing significant harm to human health and the ecological environment. CO, as a colorless and odorless gas, is easily inhaled, damaging the heart and nervous system; long-term exposure to high concentrations of CO can exacerbate various chronic diseases.

[0003] The "dual-carbon" strategy of high-energy-consuming industries presents a significant demand for the coordinated treatment of multiple pollutants. NOx removal from industrial flue gas is energy-intensive, while fugitive CO emissions severely restrict the effectiveness of environmental governance. In existing technologies, selective catalytic reduction (SCR) for NOx removal typically requires temperatures controlled between 160-400℃; selective non-catalytic reduction (SNCR) for NOx removal generally requires temperatures between 800℃ and 1100℃. Current technologies often use flue gas with relatively low temperatures, necessitating temperature increases to a suitable range for NOx removal. This process, due to the typically large volume of flue gas, consumes substantial amounts of fuel to heat the desulfurized flue gas, resulting in resource waste and secondary environmental pollution. CN112403218A discloses a flue gas decarbonization and denitrification system and method, which heats the flue gas for decarbonization treatment, and then heats it again for denitrification treatment. Due to the large volume of flue gas to be treated, the two heating treatments during the process significantly increase energy consumption, and the equipment is complex and has high operation and maintenance costs. CN112403219A discloses a flue gas decarbonization and denitrification system and method, which heats the flue gas for denitrification treatment, and then heats it again for decarbonization treatment. This also directly heats the flue gas by setting a heater on the conveying pipeline, resulting in limited heating effect on the flue gas. It can only slightly increase the temperature of the flue gas. For flue gas with low temperature, it cannot directly raise the temperature of the flue gas to the optimal temperature for the denitrification reaction after passing through the heater, thus limiting the use of this system for flue gas denitrification and decarbonization. CN211753781U discloses a flue gas multi-pollutant synergistic purification device, which injects ammonia into the original flue gas pipeline and uses a heat medium as the ammonia transport carrier. The device has the following technical problems: 1. The ammonia gas is not mixed evenly with the heat medium carrier; 2. The ammonia gas is not mixed evenly with the raw flue gas; 3. The mixing effect of the heat medium and the raw flue gas is not good. As a result, when the mixed gas of the raw flue gas, heat medium and ammonia enters the denitrification device, the gas composition is unstable, resulting in low denitrification efficiency and difficulty in guaranteeing the denitrification effect. Utility Model Content

[0004] To address the technical problems in existing flue gas denitrification and decarbonization processes, such as uneven gas mixing, limited flue gas temperature increase, high energy consumption, and difficulty in guaranteeing denitrification efficiency, this invention proposes a flue gas denitrification and decarbonization system. This system directly mixes raw flue gas with hot air to raise its temperature. Therefore, it is unaffected by the raw flue gas temperature and the amount of hot air added can be adjusted as needed to ensure the flue gas temperature reaches the optimal denitrification and decarbonization range. This improves the system's adaptability to raw flue gas and thus guarantees desulfurization and denitrification efficiency. Simultaneously, by installing a high-low temperature fluid mixer on the raw flue gas conveying pipeline for mixing the raw flue gas and hot air, the uniformity of the mixed gas is improved, thereby ensuring the uniformity and stability of the temperature entering the denitrification and decarbonization chamber and effectively enhancing the denitrification and decarbonization effect.

[0005] According to the technical solution provided by this utility model, a flue gas denitrification and decarbonization system is provided.

[0006] A flue gas denitrification and decarbonization system includes a flue gas conveying pipeline, a denitrification and decarbonization chamber, and a clean flue gas output pipeline. The clean flue gas output pipeline is connected to the outlet of the denitrification and decarbonization chamber. The system also includes a high-low temperature fluid mixer, which includes a flue gas inlet, a hot air inlet, and a mixed gas outlet. The flue gas conveying pipeline is connected to the flue gas inlet, the hot air inlet is connected to the hot air conveying pipeline, and the mixed gas outlet is connected to the inlet of the denitrification and decarbonization chamber via the mixed gas conveying pipeline.

[0007] In this invention, the high-low temperature fluid mixer has a shell-and-tube structure, comprising a tube body and a shell. The upstream end of the shell is the flue gas inlet, connected to a flue gas conveying pipeline. The downstream end of the shell is the mixed gas outlet, also connected to a mixed gas conveying pipeline. The tube body is housed within the shell, with one end closed and the other end serving as a hot air inlet. A hot air outlet is located on the side wall of the tube body.

[0008] Preferably, the tube has a conical structure, and the inner diameter of the tube gradually decreases from the hot air inlet end to the closed end.

[0009] Preferably, hot air outlets are evenly distributed around the sidewalls of the pipe.

[0010] Preferably, the housing contains 1-20 tubes.

[0011] In this invention, an ammonia injection inlet is provided on the mixed gas conveying pipeline.

[0012] Preferably, an ammonia gas mixing device is installed inside the mixed gas conveying pipeline. The ammonia gas mixing device includes an ammonia conveying pipe and an ammonia injection branch pipe. The ammonia injection branch pipe is installed on and connected to the ammonia conveying pipe. The ammonia injection branch pipe is perpendicular to the axial direction of the ammonia conveying pipe. One end of the ammonia conveying pipe is closed, and the other end is connected to the ammonia injection inlet.

[0013] Preferably, the ammonia delivery pipe is provided with 2-100 ammonia injection branches, and the axial angle between adjacent ammonia injection branches is 5-90°.

[0014] In this invention, the air inlet of the denitrification and decarbonization chamber is located at the top, and the mixed gas conveying pipe has a "7" shaped structure, which connects to the air inlet of the denitrification and decarbonization chamber after bending. A flow guiding device is provided inside the bend of the mixed gas conveying pipe. The flow guiding device is an arc-shaped plate structure.

[0015] Preferably, louvers are provided at the connection between the mixed gas delivery pipeline and the air inlet of the denitrification and decarbonization chamber.

[0016] Preferably, the system also includes a heat exchanger. The high-temperature end of the heat exchanger is connected to the clean flue gas output pipe, and the low-temperature end of the heat exchanger is connected to the flue gas delivery pipe.

[0017] Preferably, the heat exchanger is a GGH heat exchanger.

[0018] In this invention, the flue gas treatment system is an improvement upon the traditional SCR denitrification device, employing a vertical tower structure. The reactor is divided into three functional areas: an inlet pretreatment section, a denitrification and carbon removal catalytic section, and a latent heat recovery section. The inlet pretreatment section, as the primary functional area of ​​the reactor, mainly undertakes the tasks of flue gas flow uniformity and inlet status monitoring, creating stable operating conditions for subsequent catalytic reactions. To optimize the problem of uneven flue gas flow, a system including a high-low temperature fluid mixer (used to mix raw flue gas and hot air, improving the temperature uniformity of the mixed flue gas), a multi-media gas phase mixer (used to mix flue gas and ammonia, improving the ammonia composition uniformity of the mixed flue gas), a flue gas guiding device, and louvers (used to guide the flue gas, allowing it to enter the denitrification and decarbonization chamber uniformly) is designed. Through collaborative design, uniform flue gas distribution, temperature field optimization, and real-time monitoring of the inlet status are achieved, providing stable and clean inlet conditions for subsequent catalytic reactions.

[0019] In this invention, the core purpose of the high-low temperature fluid mixer is to rapidly and uniformly mix the low-temperature flue gas with the high-temperature hot air, ensuring that the temperature of the mixed flue gas reaches the optimal activity temperature window of the SCR denitrification catalyst (typically 180℃), thereby guaranteeing the denitrification efficiency of the system. The temperature field of the flue gas flow process after installing the high-low temperature rapid mixing device in this invention is as follows: Figure 9 As shown in the figure. Analysis shows that the temperature distribution of the device is relatively reasonable and meets the actual working conditions and design requirements.

[0020] In this invention, an ammonia-flue gas mixing device is used to achieve rapid and uniform mixing of flue gas and ammonia (NH3), ensuring uniform distribution of NH3 in the flue gas, thereby improving denitrification efficiency and reducing the risk of ammonia escape. This device employs a multi-nozzle ammonia injection system design, further utilizing an improved staggered nozzle arrangement to achieve uniform injection and mixing of ammonia into the flue gas, resulting in a homogeneous mixture of ammonia and flue gas. CFD fluid simulation studies were conducted to investigate the influence of structure and arrangement on the mixing effect, verifying that an ammonia distribution CV value ≤ 5% can be achieved; the ammonia distribution diagram is shown below. Figure 10 .

[0021] In this invention, the flue gas guiding device and louvers primarily aim to optimize the flow field distribution within the reactor, ensuring uniform passage of flue gas through the catalyst layer, thereby improving denitrification efficiency and extending catalyst lifespan. CFD analysis was performed on physical models with and without the guiding device. The longitudinal cross-sectional flow field comparison cloud diagrams of the flue gas with and without the guiding device are shown below. Figure 11 and Figure 12 As shown in the diagram, analysis reveals that the addition of the flow guiding device significantly improves the uniformity of the flow field within the reactor. The flow field is further rectified, and the flue gas flow exhibits a more reasonable and relatively uniform velocity and temperature distribution, meeting both actual operating conditions and design requirements. Furthermore, it is hoped that a flow guiding plate device capable of automatically adjusting its angle based on different flue gas velocities can be designed through simulation in the future.

[0022] In this invention, the waste heat recovery section employs a GGH (Gas-Gas Heater) heat exchanger. This device achieves efficient heat exchange between the raw flue gas (relatively low temperature) and the purified gas (relatively high temperature) through a rotating heat storage medium. The GGH heat exchanger mainly consists of a rotating heat storage disc, a drive motor, a sealing system, and a shell. The heat released by CO catalytic oxidation is absorbed by the heat storage medium. When the heat storage medium rotates to the inlet side, it transfers the heat to the low-temperature flue gas. Through heat cascade utilization, the latent chemical heat released after CO catalytic oxidation is effectively utilized for low-temperature SCR supplementary heating, thus treating waste with waste. The GGH heat exchanger is existing technology.

[0023] In this invention, the high-low temperature fluid mixer has a shell-and-tube structure. The raw flue gas passes through the shell side, while hot air passes through the tube side. After entering the tube, the hot air passes through the variable-diameter tube and then through the hot air outlet into the shell, dispersing into the raw flue gas. This achieves rapid and uniform mixing of the high and low temperature fluids, significantly improving heat exchange efficiency. This design ensures that the hot air, passing through a small diameter and multiple flow channels, fully contacts the raw flue gas, resulting in more efficient heat transfer and ensuring the temperature uniformity of the mixed flue gas. This, in turn, guarantees the stability and efficiency of the subsequent denitrification reaction. Preferably, multiple hot air outlets are evenly arranged around the sidewall of the tube; for example, eight hot air outlets are evenly arranged around the sidewall of a conical tube, ensuring that the hot air is evenly dispersed into the raw flue gas, further optimizing the heat transfer path and improving overall heat exchange efficiency.

[0024] In this invention, the ammonia gas mixing device comprises an ammonia gas delivery pipe (main pipe) and multiple ammonia injection branch pipes, each equipped with a nozzle. The ammonia injection branch pipes have a conical structure (similar to the shape of a bamboo shoot). After ammonia gas is delivered to the ammonia gas mixing device, it forms multiple flow channels in the conical injection branch pipes, and is evenly injected into the flue gas through these multiple injection branch pipes. Preferably, the multiple ammonia injection branch pipes are arranged in different directions, and the axial directions of adjacent ammonia injection branch pipes are at an angle, ensuring that ammonia gas is injected into the flue gas from multiple directions, forming a multi-point converging mixing area. This effectively increases the contact area between ammonia gas and flue gas, promotes uniform mixing, and ensures the comprehensiveness and efficiency of the denitrification reaction.

[0025] In this invention, a flow guiding device is installed inside the mixed gas conveying pipeline. The flow guiding device is an arc-shaped plate structure. Designed based on fluid dynamics principles, the arc-shaped plate effectively guides the mixed gas to flow uniformly along the inner wall of the pipeline, reducing turbulence and backflow, and further improving the mixing effect. The installation position and angle of the flow guiding device are adjustable to adapt to different operating conditions, ensuring that the mixed gas maintains a stable flow velocity and temperature distribution during the conveying process, providing ideal conditions for the subsequent denitrification reaction.

[0026] In this invention, a louver is provided at the connection between the mixed gas conveying pipeline and the air inlet of the denitrification and decarbonization chamber. The louver can adjust its opening and closing angle according to the airflow conditions, optimizing the airflow distribution and ensuring that the mixed gas enters the denitrification and decarbonization chamber evenly, thereby improving the reaction efficiency. By precisely controlling the airflow speed and direction, the louver effectively reduces dead air zones, improves the overall denitrification and decarbonization effect, and ensures that emissions meet standards.

[0027] In this invention, by setting up a heat exchanger, the flue gas releases heat after denitrification and decarbonization. The temperature of the treated flue gas is relatively high. The heat of the treated flue gas is recovered and reused through a heat exchanger (such as a GGH heat exchanger) to heat the original flue gas, thereby realizing the recycling of heat and significantly improving energy utilization efficiency.

[0028] Compared with the prior art, the technical solution provided by this utility model has the following beneficial technical effects:

[0029] 1. A high-low temperature fluid mixer is installed on the original flue gas conveying pipeline. Hot air passes through a small diameter and multiple flow channels to fully contact the original flue gas, making heat transfer more efficient and ensuring the temperature uniformity of the flue gas after mixing.

[0030] 2. The ammonia gas and flue gas are mixed evenly through the ammonia gas and flue gas mixing device, which effectively improves the comprehensiveness and efficiency of the denitrification reaction, reduces the ammonia escape rate, and optimizes the overall denitrification effect.

[0031] 3. Through the synergistic effect of the airflow guiding device and louvers, the airflow distribution is further optimized, energy loss is reduced, system stability is improved, and the denitrification and decarbonization process is ensured to operate efficiently and meet environmental emission standards. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of a flue gas denitrification and decarbonization system according to the present invention;

[0033] Figure 2 This is a schematic diagram of the structure of a high and low temperature fluid mixer in a flue gas denitrification and decarbonization system according to the present invention;

[0034] Figure 3 This is a schematic diagram of a conical structure for the tube body of a high-low temperature fluid mixer in a flue gas denitrification and decarbonization system according to the present invention.

[0035] Figure 4 This is a schematic diagram of the structure of an ammonia-flue gas mixing device in a flue gas denitrification and decarbonization system according to the present invention;

[0036] Figure 5 This is a schematic diagram of the ammonia injection branch pipe layout of an ammonia gas mixing device in a flue gas denitrification and decarbonization system according to the present invention.

[0037] Figure 6 This is a schematic diagram of a gas guiding structure in a flue gas denitrification and decarbonization system according to the present invention;

[0038] Figure 7 This is a schematic diagram of the layout of the denitrification and decarbonization chambers in a flue gas denitrification and decarbonization system according to this utility model;

[0039] Figure 8 This is a schematic diagram of a flue gas denitrification and decarbonization system with a heat exchanger according to the present invention;

[0040] Figure 9 This is a schematic diagram of the temperature field of the flue gas flow process after the high and low temperature fluid mixer in the system of this utility model is used in Application Example 1;

[0041] Figure 10This is a diagram showing the ammonia distribution at the inlet of the denitrification and decarbonization chamber after the ammonia flue gas mixing device in the system of this invention, as shown in Application Example 1.

[0042] Figure 11 The flow field cloud diagram of the longitudinal section of flue gas without a flow guiding structure is used in the application embodiment 1.

[0043] Figure 12 The flow field cloud diagram of the longitudinal section of flue gas with a flow guiding structure is used in the application embodiment 2.

[0044] Figure label:

[0045] 1: Denitrification and decarbonization chamber; 2: High and low temperature fluid mixer; 201: Flue gas inlet; 202: Hot air inlet; 203: Mixed gas outlet; 204: Pipe body; 205: Shell; 20501: Hot air outlet; 3: Ammonia injection inlet; 4: Ammonia flue gas mixing device; 401: Ammonia conveying pipe; 402: Ammonia injection branch pipe; 5: Flow guiding device; 6: Louver; 7: Heat exchanger; L1: Flue gas conveying pipeline; L2: Clean flue gas output pipeline; L3: Hot air conveying pipeline; L4: Mixed gas conveying pipeline. Detailed Implementation

[0046] The technical solution of the present invention will be illustrated below with examples. The scope of protection sought by the present invention includes, but is not limited to, the following embodiments. Example 1

[0047] like Figure 1 As shown, a flue gas denitrification and decarbonization system includes a flue gas conveying pipe L1, a denitrification and decarbonization chamber 1, and a clean flue gas output pipe L2. The clean flue gas output pipe L2 is connected to the outlet of the denitrification and decarbonization chamber 1. The system also includes a high-low temperature fluid mixer 2, which includes a flue gas inlet 201, a hot air inlet 202, and a mixed gas outlet 203. The flue gas conveying pipe L1 is connected to the flue gas inlet 201, the hot air inlet 202 is connected to the hot air conveying pipe L3, and the mixed gas outlet 203 is connected to the inlet of the denitrification and decarbonization chamber 1 through a mixed gas conveying pipe L4. Example 2

[0048] like Figure 2 As shown, Embodiment 1 is repeated, except that the high and low temperature fluid mixer 2 has a shell-and-tube structure, including a tube body 204 and a shell 205. The upstream end of the shell 205 is the flue gas inlet 201, which is connected to the flue gas conveying pipe L1. The downstream end of the shell 205 is the mixed gas outlet 203, which is connected to the mixed gas conveying pipe L4. The tube body 204 is disposed inside the shell 205, with one end of the tube body 204 closed and the other end being a hot air inlet 202. A hot air outlet 20501 is provided on the side wall of the tube body 204. Example 3

[0049] like Figure 3 As shown, Example 2 is repeated, except that the tube 204 is a conical structure and the inner diameter of the tube 204 gradually decreases from the hot air inlet 202 end to the closed end. Example 4

[0050] Repeat Example 3, except that hot air outlets 20501 are evenly arranged around the side wall of the tube 204. Example 5

[0051] The same as embodiment 3 is repeated, except that the housing 205 contains 5 tubes 204. Example 6

[0052] Example 3 is repeated, except that an ammonia injection inlet 3 is provided on the mixed gas delivery pipeline L4. Example 7

[0053] like Figure 4 As shown, Embodiment 6 is repeated, except that an ammonia gas mixing device 4 is provided inside the mixed gas conveying pipeline L4. The ammonia gas mixing device 4 includes an ammonia conveying pipe 401 and an ammonia injection branch pipe 402. The ammonia injection branch pipe 402 is installed on and connected to the ammonia conveying pipe 401. The ammonia injection branch pipe 402 is perpendicular to the axial direction of the ammonia conveying pipe 401. One end of the ammonia conveying pipe 401 is closed, and the other end is connected to the ammonia injection inlet 3. Example 8

[0054] like Figure 5 As shown, Example 7 is repeated, except that the ammonia delivery pipe 401 is provided with 10 ammonia injection branch pipes 402, and the axial angle between adjacent ammonia injection branch pipes 402 is 60°. Example 9

[0055] like Figure 6 As shown, Example 8 is repeated, except that the air inlet of the denitrification and decarbonization chamber 1 is located at the top, and the mixed gas conveying pipe L4 has a "7" shaped structure, which connects to the air inlet of the denitrification and decarbonization chamber 1 after bending. A flow guiding device 5 is provided in the inner cavity of the bend of the mixed gas conveying pipe L4. The flow guiding device 5 is an arc-shaped plate structure. Example 10

[0056] Example 9 is repeated, except that a louver 6 is provided at the connection between the mixed gas conveying pipeline L4 and the air inlet of the denitrification and decarbonization chamber 1. Example 11

[0057] like Figure 8 As shown, Embodiment 1 is repeated, except that the system also includes a heat exchanger 7. The high-temperature end of the heat exchanger 7 is connected to the clean flue gas output pipe L2, and the low-temperature end of the heat exchanger 7 is connected to the flue gas conveying pipe L1. The heat exchanger 7 is a GGH heat exchanger.

[0058] Application Example 1

[0059] Using the system described in Example 8, the flue gas passes through a flue gas conveying pipe and is mixed with hot air in a high-low temperature fluid mixer, thereby increasing the temperature of the flue gas (the temperature field of the mixed flue gas is as follows). Figure 9 (As shown); the heated flue gas enters the ammonia flue gas mixing device through the mixed gas conveying pipeline. Inside the ammonia flue gas mixing device, the mixed gas is mixed with ammonia to obtain flue gas with ammonia mixture (the distribution of ammonia in the gas with ammonia mixture is shown in the figure). Figure 10 (As shown); the gas after mixing with ammonia is transported to the denitrification and decarbonization chamber, which is equipped with a denitrification catalyst layer and a decarbonization catalyst layer. The flue gas undergoes denitrification and decarbonization reactions under the action of the catalysts, and the purified flue gas is discharged through the clean flue gas output pipe.

[0060] Application Example 2

[0061] Using the system described in Example 11, flue gas passes through a flue gas conveying pipe and is mixed with hot air in a high-low temperature fluid mixer, thereby increasing the temperature of the flue gas (the temperature field of the mixed flue gas is as follows). Figure 9 (As shown); the heated flue gas enters the ammonia flue gas mixing device through the mixed gas conveying pipeline. Inside the ammonia flue gas mixing device, the mixed gas is mixed with ammonia to obtain flue gas with ammonia mixture (the distribution of ammonia in the gas with ammonia mixture is shown in the figure). Figure 10 (As shown); the gas mixed with ammonia is then transported to the denitrification and decarbonization chamber through a mixed gas conveying pipeline. Within the pipeline, the gas flow is optimized by a flow guide device and louvers, ensuring uniform entry into the denitrification and decarbonization chamber (the longitudinal cross-sectional flow field cloud diagram of the flue gas after flow guidance is shown in the figure). Figure 12 (As shown in the figure) The denitrification and decarbonization chamber is equipped with a denitrification catalyst layer and a decarbonization catalyst layer. The flue gas undergoes denitrification and decarbonization reactions under the action of the catalyst, and the purified flue gas is discharged through the clean flue gas output pipe.

Claims

1. A flue gas denitration and decarbonization system, comprising a flue gas conveying pipeline (L1), a denitration and decarbonization chamber (1), and a clean flue gas output pipeline (L2); the clean flue gas output pipeline (L2) is connected with a gas outlet of the denitration and decarbonization chamber (1); characterized in that: The system further comprises a high-low temperature fluid mixer (2), the high-low temperature fluid mixer (2) comprising a flue gas inlet end (201), a hot air inlet (202), and a mixed gas outlet end (203); the flue gas conveying pipeline (L1) is connected with the flue gas inlet end (201), the hot air inlet (202) is connected with the hot air conveying pipeline (L3), and the mixed gas outlet end (203) is connected with the flue gas inlet of the denitration and decarbonization chamber (1) through a mixed gas conveying pipeline (L4).

2. The flue gas denitration and decarbonization system according to claim 1, characterized in that: The high-low temperature fluid mixer (2) is of a tube-shell structure, comprising a tube body (204) and a shell (205); the upstream end of the shell (205) is the flue gas inlet end (201) and is in communication with the flue gas conveying pipeline (L1); the downstream end of the shell (205) is the mixed gas outlet end (203) and is in communication with the mixed gas conveying pipeline (L4); the tube body (204) is arranged in the shell (205), one end of the tube body (204) is closed, and the other end is the hot air inlet (202); the sidewall of the tube body (204) is provided with a hot air outlet (20501).

3. The flue gas denitration and decarbonization system according to claim 2, characterized in that: The tube body (204) is of a conical structure, and the inner diameter of the tube body (204) gradually decreases from the hot air inlet (202) end to the closed end.

4. The flue gas denitration and decarbonization system according to claim 2 or 3, characterized in that: The sidewall of the tube body (204) is uniformly provided with the hot air outlets (20501) around; and / or 1-20 tube bodies (204) are arranged in the shell (205).

5. The flue gas denitration and decarbonization system according to claim 1, characterized in that: The mixed gas conveying pipeline (L4) is provided with an ammonia gas injection inlet (3).

6. The flue gas denitration and decarbonization system according to claim 5, characterized in that: The mixed gas conveying pipeline (L4) is provided with an ammonia gas flue gas mixing device (4); the ammonia gas flue gas mixing device (4) comprises an ammonia gas conveying pipe (401) and an ammonia injection branch pipe (402); the ammonia injection branch pipe (402) is arranged on the ammonia gas conveying pipe (401) and is in communication; the ammonia injection branch pipe (402) is perpendicular to the axis direction of the ammonia gas conveying pipe (401); one end of the ammonia gas conveying pipe (401) is closed, and the other end is in communication with the ammonia gas injection inlet (3).

7. The flue gas denitration and decarbonization system according to claim 6, characterized in that: 2-100 ammonia injection branch pipes (402) are arranged on the ammonia gas conveying pipe (401), and the included angle of the axial directions of adjacent ammonia injection branch pipes (402) is 5-90°.

8. The flue gas denitration and decarbonization system according to claim 1, characterized in that: The flue gas inlet of the denitration and decarbonization chamber (1) is located at the upper portion, the mixed gas conveying pipeline (L4) is of a "7" type structure, is in communication with the flue gas inlet of the denitration and decarbonization chamber (1) after being bent, the inner cavity of the bending portion of the mixed gas conveying pipeline (L4) is provided with a flow guide device (5); the flow guide device (5) is of an arc plate structure; The mixed gas conveying pipeline (L4) is provided with a louver (6) at the connection position with the flue gas inlet of the denitration and decarbonization chamber (1).

9. The flue gas denitration and decarbonization system according to claim 1, characterized in that: The system further comprises a heat exchanger (7), the high temperature end of the heat exchanger (7) is connected with the clean flue gas output pipeline (L2), and the low temperature end of the heat exchanger (7) is connected with the flue gas conveying pipeline (L1).

10. The flue gas denitration and decarbonization system according to claim 9, characterized in that: The heat exchanger (7) is a GGH heat exchanger.

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