Flue gas denitration device for waste heat boiler

Abstract

The present application provides a waste heat boiler flue gas denitration device, relates to the field of flue gas denitration.The waste heat boiler flue gas denitration device, comprising a urea pyrolysis furnace and a flue, the flue is installed at the smoke outlet of the urea pyrolysis furnace, and the urea pyrolysis furnace can draw the flue gas into the flue through the dilution fan, the upper end of the flue is fixedly connected with a heat storage assembly, the heat storage assembly can store the heat of the flue gas in the flue, and can also release the stored heat.The waste heat boiler flue gas denitration device, the heat storage assembly can store part of the temperature of the flue gas, when the temperature of the flue gas exceeds four hundred degrees, the turbine set can accelerate the flow of the flue gas and rapidly cool down, the angle of the plurality of guide vanes can automatically control the rotating speed of the turbine set, and the greater the rotating speed, the faster the flue gas flow rate, so as to cool down, and vice versa, the smaller the rotating speed, the slower the flue gas flow rate, and the stored heat can be released to achieve temperature rise, thereby solving the problems raised in the background art.

Description

Technical Field

[0001] This invention relates to the field of flue gas denitrification, specifically to a flue gas denitrification device for waste heat boilers. Background Technology

[0002] Flue gas denitrification refers to the process of removing nitrogen oxides from flue gas through methods such as reduction and oxidation. Nitrogen oxides are not only air pollutants but also one of the main causes of photochemical smog. Waste heat boilers are devices that use waste heat generated during industrial production to generate electricity or heat. During operation, they produce a large amount of flue gas. Nitrogen oxides in the flue gas can enter the lungs and cause bronchitis or emphysema, which has an adverse effect on human health. Therefore, it is essential to discharge the flue gas in the boiler into a flue gas denitrification device for the denitrification of waste heat boilers.

[0003] The optimal temperature for denitrification reactions is typically between 300-400℃. Within this temperature range, the active sites on the catalyst surface can fully adsorb ammonia and NOx gases, thereby promoting the denitrification reaction. At the same time, a moderate temperature can effectively prevent overheating and deactivation of the catalyst, ensuring its long-term stability. However, the temperature of the flue gas inside existing denitrification devices is greatly affected by the boiler materials themselves. The flue gas temperature generated by the waste heat boiler during material processing is relatively high, which can easily lead to catalyst loss and deactivation, affecting the denitrification effect. When the materials inside the boiler are not fully combusted or blockage occurs, the temperature of the discharged flue gas will be lower. At low temperatures, the catalyst activity is lower, resulting in poor denitrification efficiency. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a waste heat boiler flue gas denitrification device, which solves the problems mentioned in the background section.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a waste heat boiler flue gas denitrification device, comprising a urea pyrolysis furnace and a flue. The flue is installed at the exhaust port of the urea pyrolysis furnace, and the urea pyrolysis furnace can draw flue gas into the flue through a dilution fan. A heat storage component is fixedly connected to the upper end of the flue. The heat storage component can store the heat of the flue gas in the flue and can also release the stored heat. A reactor is fixedly connected to the other end of the heat storage component. A catalyst assembly is installed inside the reactor. A fixed plate is fixedly connected inside the heat storage component. A turbine assembly is installed inside the fixed plate. The turbine assembly can rotate and can transport the flue gas in the flue to the reactor. A rectifier is fixedly installed inside the reactor. The heat storage component has four circumferentially arranged heat inlets inside. The inner wall of the heat storage component is equipped with four circumferentially arranged control components. The four control components correspond to the four heat inlets respectively. When the flue gas temperature is too high, the four control components can control the four heat inlets to open respectively. When the flue gas temperature is too low, the four control components can control the four heat inlets to close respectively.

[0006] The fixed disk has multiple rotating parts arranged in a circle inside. Each rotating part has a guide vane fixedly connected to one end and a movable part fixedly connected to the other end. The heat storage component has a rotating ring inside. Each movable part is engaged with the rotating ring. When the rotating ring rotates, it can drive multiple movable parts to rotate. The heat storage component has a sealing ring fixedly connected inside. The sealing ring is in contact with multiple guide vanes.

[0007] Preferably, the catalyst group consists of a first catalyst layer, a second catalyst layer, a third catalyst layer, and a spare catalyst layer. The first catalyst layer, the second catalyst layer, the third catalyst layer, and the spare catalyst layer are arranged at equal distances and are all fixedly connected to the reactor.

[0008] Preferably, the heat storage component consists of a storage shell and a sandbag. The inner wall of the storage shell has multiple heat dissipation ports arranged in a circular pattern, and the interior of the storage shell has a cavity. The sandbag is fixedly connected to the inner wall of the cavity.

[0009] Preferably, the sandbag is filled with sand and is breathable, allowing gas from the heat inlet to enter the sandbag and also to enter the heat outlet, forming a gas channel.

[0010] Preferably, each of the control components comprises an expansion chamber, a moving part, a connecting part, spring A, spring B, and a baffle. The connecting part is fixedly connected to the storage shell, the baffle is fixedly connected to the rotating ring, the end of the connecting part away from the storage shell is hinged to the end of the expansion chamber away from the storage shell, the moving part is slidably connected to the expansion chamber and the two are in close contact, the other end of the moving part is hinged to the baffle, each baffle is fixedly connected to the rotating ring, the two ends of spring A are fixedly connected to the expansion chamber and the moving part respectively, the two ends of spring B are fixedly connected to the expansion chamber and the connecting part respectively, the expansion chamber is filled with gas, and the gas can expand when the temperature is too high.

[0011] Preferably, the baffle is arc-shaped and in close contact with the inner wall of the storage shell.

[0012] Preferably, each of the guide vanes is arc-shaped, so that when the flue gas temperature is too high, every two adjacent guide vanes can come into contact, and multiple guide vanes can surround and form a circle.

[0013] Preferably, the sandbag is annular in shape and its size is equal to that of the cavity.

[0014] Preferably, an ammonia injection grid and a static mixer are fixedly installed inside the flue, with the ammonia injection grid located to the right of the static mixer.

[0015] Preferably, one side of the fixed disk has a plurality of circumferentially arranged limiting grooves, and each limiting groove is rotatably connected to a limiting block. The multiple limiting blocks are respectively fixedly connected to multiple rotating parts, and the range of rotation of the limiting block within the limiting groove does not exceed ninety degrees.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This waste heat boiler flue gas denitrification device utilizes high-temperature flue gas generated by the waste heat boiler. The flue gas flows along the flue through a heat storage component and a reactor containing a catalyst. When the flue gas temperature exceeds 400 degrees Celsius, the expansion chamber of the control component begins to expand, opening the baffle and allowing the high-temperature flue gas to enter the storage shell. The heat storage component stores part of the flue gas temperature. The flue gas flowing in the flue drives the turbine unit to rotate. The turbine unit's rotation increases the pressure and improves the flue gas flow velocity. As the flue gas flow velocity increases, the temperature decreases. Furthermore, the angles of multiple guide vanes can be automatically adjusted according to changes in flue gas temperature. The angles of the multiple guide vanes can automatically control the turbine unit's rotation speed. The higher the rotation speed, the faster the flue gas flow velocity, thus achieving cooling; conversely, the lower the rotation speed, the slower the flue gas flow velocity, which releases the stored heat, achieving heating. This allows the catalyst to react with the flue gas and ammonia at a suitable temperature, solving the problems mentioned in the background technology.

[0018] 2. This waste heat boiler flue gas denitrification device uses a urea pyrolysis furnace to draw flue gas into the flue through a dilution fan. An ammonia injection grid is arranged in the flue. After the ammonia and air are evenly mixed, the gas enters the heat storage component and the reactor inlet through the ammonia injection grid and static mixer. Then, the rectifier controls the sulfur dioxide and helium oxides in the flue gas, and also purifies it to ensure safety and prevent secondary pollution. Finally, the gas enters the reactor filled with catalyst. Under the action of the catalyst, nitrogen oxides and ammonia undergo a reduction reaction to produce pollution-free nitrogen and water, thereby reducing the emission of air pollutants from the waste heat boiler and protecting the environment and human health. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the urea pyrolysis furnace and flue structure of the present invention;

[0020] Figure 2 This is a schematic diagram of the reactor and flue structure of the present invention;

[0021] Figure 3 This is a cross-sectional view of the reactor structure of the present invention;

[0022] Figure 4 For the present invention Figure 3 An enlarged view of the structural schematic diagram at point A in the middle;

[0023] Figure 5 This is a schematic diagram of the structure of the control component of the present invention when it is closed;

[0024] Figure 6 This is a cross-sectional view of the control component structure of the present invention;

[0025] Figure 7 This is a schematic diagram of the structure of the guide vane of the present invention when it is closed;

[0026] Figure 8 This is a cross-sectional view of the sandbag and sand of the present invention from the side view.

[0027] Figure 9 This is an enlarged view of the mounting position of the rotating component of the present invention.

[0028] The components include: 1. Urea pyrolysis furnace; 2. Flue; 3. Heat storage assembly; 301. Storage shell; 302. Sandbag; 4. Reactor; 5. Catalyst assembly; 501. First layer catalyst; 502. Second layer catalyst; 503. Third layer catalyst; 504. Backup catalyst; 6. Fixed plate; 7. Turbine unit; 8. Rectifier; 9. Heat inlet; 10. Control assembly; 101. Expansion chamber; 102. Moving part; 103. Connecting part; 104. Baffle; 11. Rotating part; 12. Guide vane; 13. Moving part; 14. Rotating ring; 15. Sealing ring; 16. Heat exhaust port; 17. Sand; 18. Ammonia injection grid; 19. Static mixer; 20. Limiting groove; 21. Limiting block. Detailed Implementation

[0029] like Figures 1-9As shown, the waste heat boiler flue gas denitrification device includes a urea pyrolysis furnace 1 and a flue 2. The flue 2 is installed at the exhaust port of the urea pyrolysis furnace 1, and the urea pyrolysis furnace 1 can draw flue gas into the flue 2 through a dilution fan. A heat storage component 3 is fixedly connected to the upper end of the flue 2. The heat storage component can store the heat of the flue gas in the flue 2 and can also release the stored heat. An ammonia injection grid 18 and a static mixer 19 are fixedly installed inside the flue 2. The ammonia injection grid 18 is located to the right of the static mixer 19. The ammonia injection grid 18 can inject ammonia gas, and the static mixer 19 can mix the ammonia gas with the flue gas. The gas is fully mixed. The heat storage component 3 consists of a storage shell 301 and a sandbag 302. The inner wall of the storage shell 301 has multiple circumferentially arranged heat dissipation ports 16. A cavity is formed inside the storage shell 301. The sandbag 302 is fixedly connected to the inner wall of the cavity. Sand 17 is filled inside the sandbag 302. The sandbag 302 is breathable, allowing gas from the heat inlet 9 to enter the sandbag 302 and also to enter the heat dissipation ports 16, forming a gas channel. The sand 17 absorbs heat and retains it for a long time. The sandbag 302 is annular and its size is equal to that of the cavity. The other side of the heat storage component 3... A reactor 4 is fixedly connected to the reactor 4. A catalyst assembly 5 is installed inside the reactor 4. The catalyst assembly 5 consists of a first catalyst layer 501, a second catalyst layer 502, a third catalyst layer 503, and a spare catalyst 504. The first catalyst layer 501, the second catalyst layer 502, the third catalyst layer 503, and the spare catalyst 504 are arranged at equal intervals and are all fixedly connected to the reactor 4. A fixed disk 6 is fixedly connected inside the heat storage assembly 3. Multiple circumferentially arranged limiting grooves 20 are opened on one side of the fixed disk 6. Each limiting groove 20 has a rotatably connected limiting block 21 inside. Multiple limiting blocks 21 are fixedly connected to multiple rotating parts 11 respectively. The limiting block 21 rotates within the limiting groove 20 by no more than 90 degrees. A turbine unit 7 is installed inside the fixed disk 6. The turbine unit 7 can rotate and transport the flue gas in the flue 2 to the reactor 4. A rectifier 8 is fixedly installed inside the reactor 4. The main function of the rectifier 8 is to effectively control sulfur dioxide and its helium oxides in the flue gas, and it can also purify and treat them to ensure safety and prevent secondary pollution. The reactor 4 can reduce nitrogen dioxide and ammonia in the flue gas under the action of the catalyst group 5.

[0030] The heat storage component 3 has four circumferentially arranged heat inlets 9 inside. Four circumferentially arranged control components 10 are installed on the inner wall of the heat storage component 3. Each control component 10 corresponds to one of the four heat inlets 9. When the flue gas temperature is too high, the four control components 10 can control the opening of each of the four heat inlets 9; when the flue gas temperature is too low, the four control components 10 can control the closing of each of the four heat inlets 9. Each control component 10 consists of an expansion chamber 101, a moving part 102, a connecting part 103, spring A, spring B, and a baffle 104. The connecting part 103 is fixedly connected to the storage shell 301, and the baffle 104 is fixedly connected to the rotating ring 14. The end of the connecting part 103 away from the storage shell 301 is hinged to the end of the expansion chamber 101 away from the storage shell 301. The moving part 102... 2 is slidably connected to the expansion chamber 101 and the two are in close contact. The other end of the moving part 102 is hinged to the baffle 104. Each baffle 104 is fixedly connected to the rotating ring 14. The two ends of the spring A are fixedly connected to the expansion chamber 101 and the moving part 102 respectively. The two ends of the spring B are fixedly connected to the expansion chamber 101 and the connecting part 103 respectively. The expansion chamber 101 is filled with gas. When the temperature is too high, the gas can expand. When the flue gas temperature is too high, the gas inside the expansion chamber 101 will expand and drive the moving part 102 to move, thereby causing the baffle 104 to shift, so as to open the heat inlet 9. Moreover, the higher the temperature, the larger the range of the heat inlet 9 opening. At this time, the springs A and B are both in a static state. The baffle 104 is arc-shaped and in close contact with the inner wall of the storage shell 301.

[0031] The fixed disk 6 has multiple rotating parts 11 arranged in a circle inside. Each rotating part 11 has a guide vane 12 fixedly connected to one end and a movable part 13 fixedly connected to the other end. Each guide vane 12 is arc-shaped. When the flue gas temperature is too high, every two adjacent guide vanes 12 can contact each other, and the multiple guide vanes 12 can surround and form a circle. The heat storage component 3 has a rotating ring 14 inside. Each movable part 13 is engaged with the rotating ring 14. When the rotating ring 14 rotates, it can drive the multiple movable parts 13 to rotate. The heat storage component 3 has a sealing ring 15 fixedly connected inside. The sealing ring 15 contacts the multiple guide vanes 12.

[0032] In operation, the flue gas is first drawn into the flue duct 2 by the urea pyrolysis furnace 1 through the dilution fan. The ammonia injection grid 18 is arranged in the flue duct 2. After the ammonia and air are evenly mixed, the gas enters the heat storage component 3 and the inlet of the reactor 4 through the ammonia injection grid 18 and the static mixer 19. Then, the sulfur dioxide and helium oxides in the flue gas are controlled by the rectifier 8, which can also purify the gas to ensure safety and prevent secondary pollution. Finally, the gas enters the reactor 4, where nitrogen oxides and ammonia undergo a reduction reaction under the action of the catalyst group 5 to generate pollution-free nitrogen and water. This reduces the emission of air pollutants from the waste heat boiler and protects the environment and human health.

[0033] Next, as the flue gas passes through the turbine unit 7, it drives the turbine unit 7 to rotate, propelling the flue gas towards the reactor 4. The flue gas undergoes a denitrification reaction in the catalyst group 5. When the flue gas temperature is too high and exceeds a predetermined value, the gas inside the four expansion chambers 101 expands due to heat, pushing the four moving parts 102 to move. The four moving parts 102 then drive the four baffles 104 to move along the inner wall of the storage shell. At this time, the four baffles 104 open the four heat inlets 9, allowing the flue gas to contact the sandbags 302 and store heat in the sand 17. The baffles 104 are fixedly connected to the rotating ring 14. When the baffles 104 move, they drive the rotating ring 14 to rotate, which in turn drives multiple moving parts 13 to rotate. These multiple moving parts 13 then drive... The tilt angle of multiple guide vanes 12 changes. At this time, the maximum tilt of multiple guide vanes 12 should surround and form a circle. When multiple guide vanes 12 surround and form a circle, multiple guide vanes 12 can form a sealed space, allowing gas to flow from one direction of the turbine unit 7, making the resistance around the turbine unit 7 smaller and the rotation speed faster, thereby accelerating the flow rate of the flue gas and cooling the flue gas. Since the temperature of the catalyst is changed by the temperature of the flue gas, when the flue gas is cooled, the environment of the catalyst can be cooled. When the material inside the waste heat boiler is not fully burned or is blocked inside, the temperature of the discharged flue gas will be lower. When the temperature of the flue gas is lower, the gas temperature in the expansion chamber 101 drops to the threshold value, and the elastic deformation of springs A and B... Under the action of the variable force, multiple baffles 104 can reset and block the heat inlet 9, stopping the storage of heat energy, thereby reducing heat loss. They can also cause the baffles 104 to drive the rotating ring 14 to move in the opposite direction. The rotating ring 14, through multiple moving parts 13 and multiple rotating parts 11, drives multiple guide vanes 12 to shift, thereby changing the opening angle of the multiple guide vanes 12. When the multiple guide vanes 12 open, the hot air inside the storage shell 301 is released from the multiple sands 17 and discharged from the multiple heat exhaust ports 16. It should be noted that the smaller the angle of the guide vanes 12, the better the sealing within the space enclosed by the guide vanes 12, the higher the pressure, the greater the impact of the flue gas on the turbine blades of the turbine unit 7, the higher the turbine speed, and the faster the start-up speed, much like turning on a tap. A rubber hose is inserted on top. To spray water further, the hose opening needs to be squeezed smaller for the same water pressure; to spray less, it needs to be loosened slightly. If the water pressure is already low and you want it to spray further, the hose needs to be squeezed tighter. Therefore, when the guide vanes 12 open, the turbine unit 7's speed decreases, the flue gas velocity decreases, and the heat loss rate decreases. Furthermore, the hot gas discharged from the multiple exhaust ports 16 can raise the temperature of the flue gas to a suitable level. The optimal temperature for the denitrification reaction is typically between 300-400℃. Within this temperature range, the active sites on the catalyst assembly 5 can fully adsorb ammonia and NOx gases, thus promoting the denitrification reaction. At the same time, a suitable temperature effectively prevents overheating and deactivation of the catalyst assembly 5.To ensure the long-term stability of catalyst group 5.

[0034] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A waste heat boiler flue gas denitrification device, comprising a urea pyrolysis furnace (1) and a flue (2), wherein the flue (2) is installed at the exhaust port of the urea pyrolysis furnace (1), and the urea pyrolysis furnace (1) is capable of drawing flue gas into the flue (2) through a dilution fan, characterized in that: A heat storage component (3) is fixedly connected to the upper end of the flue (2). The heat storage component can store the heat of the flue gas in the flue (2) and also release the stored heat. A reactor (4) is fixedly connected to the other end of the heat storage component (3). A catalyst group (5) is installed inside the reactor (4). A fixed plate (6) is fixedly connected inside the heat storage component (3). A turbine group (7) is installed inside the fixed plate (6). The turbine group (7) can rotate and can transport the flue gas in the flue (2) to the reactor (4). A rectifier (8) is fixedly installed inside the reactor (4). The heat storage component (3) has four circumferentially arranged heat inlets (9) inside. The inner wall of the heat storage component (3) is equipped with four circumferentially arranged control components (10). The four control components (10) correspond to the four heat inlets (9) respectively. When the flue gas temperature is too high, the four control components (10) can control the four heat inlets (9) to open respectively. When the flue gas temperature is too low, the four control components (10) can control the four heat inlets (9) to close respectively. The fixed disk (6) has multiple rotating parts (11) arranged in a circle inside. Each rotating part (11) has a guide vane (12) fixedly connected to one end and a movable part (13) fixedly connected to the other end. The heat storage component (3) has a rotating ring (14) inside. Each movable part (13) is engaged with the rotating ring (14). When the rotating ring (14) rotates, it can drive multiple movable parts (13) to rotate. The heat storage component (3) has a sealing ring (15) fixedly connected inside. The sealing ring (15) is in contact with multiple guide vanes (12). Each of the control components (10) consists of an expansion cavity (101), a moving part (102), a connecting part (103), spring A, spring B, and a baffle (104). The connecting part (103) is fixedly connected to the storage shell (301), and the baffle (104) is fixedly connected to the rotating ring (14). The end of the connecting part (103) away from the storage shell (301) is hinged to the end of the expansion cavity (101) away from the storage shell (301). The moving part (102) is hinged to the expansion cavity (101). The expansion chamber (101) is slidably connected and in close contact with the other end of the moving part (102) and hinged to the baffle (104). Each baffle (104) is fixedly connected to the rotating ring (14). The two ends of the spring A are fixedly connected to the expansion chamber (101) and the moving part (102) respectively. The two ends of the spring B are fixedly connected to the expansion chamber (101) and the connecting part (103) respectively. The expansion chamber (101) is filled with gas, and the gas can expand when the temperature is too high.

2. The waste heat boiler flue gas denitrification device according to claim 1, characterized in that: The catalyst group (5) consists of a first layer catalyst (501), a second layer catalyst (502), a third layer catalyst (503) and a spare catalyst (504). The first layer catalyst (501), the second layer catalyst (502), the third layer catalyst (503) and the spare catalyst (504) are arranged at equal distances and are all fixedly connected to the reactor (4).

3. The waste heat boiler flue gas denitrification device according to claim 1, characterized in that: The heat storage component (3) consists of a storage shell (301) and a sandbag (302). The inner wall of the storage shell (301) is provided with a plurality of heat exhaust ports (16) arranged in a circular pattern. The interior of the storage shell (301) is provided with a cavity, and the sandbag (302) is fixedly connected to the inner wall of the cavity.

4. The waste heat boiler flue gas denitrification device according to claim 3, characterized in that: The sandbag (302) is filled with sand (17). The sandbag (302) is breathable, and the gas at the heat inlet (9) can enter the sandbag (302) and also enter the heat outlet (16), forming a gas channel.

5. The waste heat boiler flue gas denitrification device according to claim 1, characterized in that: The baffle (104) is arc-shaped and is in close contact with the inner wall of the storage shell (301).

6. The waste heat boiler flue gas denitrification device according to claim 1, characterized in that: Each of the guide vanes (12) is arc-shaped. When the flue gas temperature is too high, each pair of close guide vanes (12) can come into contact, and multiple guide vanes (12) can surround and form a circle.

7. The waste heat boiler flue gas denitrification device according to claim 3, characterized in that: The sandbag (302) is circular in shape and its size is equal to that of the cavity.

8. The waste heat boiler flue gas denitrification device according to claim 1, characterized in that: The flue (2) is fixedly installed with an ammonia injection grid (18) and a static mixer (19), with the ammonia injection grid (18) located to the right of the static mixer (19).

9. The waste heat boiler flue gas denitrification device according to claim 1, characterized in that: The fixed plate (6) has multiple circumferentially arranged limiting grooves (20) on one side. Each limiting groove (20) is rotatably connected to a limiting block (21). The multiple limiting blocks (21) are fixedly connected to multiple rotating parts (11) respectively. The limiting block (21) rotates within the limiting groove (20) by no more than 90 degrees.

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