Cement kiln flue gas desulfurization and denitrification system

Abstract

This utility model discloses a desulfurization and denitrification system for cement kiln flue gas, including a denitrifier, a cooler, and a desulfurizer. The denitrifier contains a mixing chamber and multiple catalyst layers arranged sequentially from top to bottom. A spiral channel is formed within the mixing chamber by a spiral plate, and a spiral tube is installed within the spiral channel. The desulfurizer is divided into an inlet chamber and a reaction chamber from bottom to top by a partition plate, with several upper gas pipes installed on the partition plate. A liquid inlet chamber is located at the upper part of the reaction chamber, and several bottom-sealed vertical pipes are rotatably connected to the bottom of the liquid inlet chamber. Fan blades are installed at the bottom of the vertical pipes, located inside the upper gas pipes. The lower part of the reaction chamber is connected to the middle part of the cooler via a drain pipe. The bottom of the denitrifier is connected to the lower part of the cooler via a gas supply pipe, and the top of the cooler is connected to the inlet chamber via a pipeline. In summary, this utility model has the advantages of thorough mixing of lime water and flue gas, reducing the flue gas desulfurization temperature, and achieving good desulfurization and denitrification effects.

Description

Technical Field

[0001] This utility model relates to the technical field of desulfurization and denitrification equipment for cement flue gas, specifically to a desulfurization and denitrification system for cement kiln flue gas. Background Technology

[0002] Cement kiln emissions are characterized by large flow rates and a wide variety of pollutants. These gases typically contain significant amounts of dust, nitrogen oxides, and sulfur dioxide, which cause severe environmental damage and must be treated to meet national, regional, and industry emission standards before being released. Flue gas desulfurization and denitrification technology is a boiler flue gas purification technology applied in the chemical industry, which generates numerous nitrogen oxides and sulfur oxides. Since nitrogen oxides and sulfur oxides are major sources of air pollution, the application of this technology offers significant benefits for environmental air purification.

[0003] Currently, during the operation of flue gas desulfurization and denitrification systems, the lime water spraying area within the desulfurization tower is relatively small, resulting in insufficient mixing and reaction between the lime water and flue gas. This leads to some flue gas not fully mixing with the lime water, affecting the desulfurization effect. Secondly, due to the high temperature of the flue gas, a large amount of sprayed lime water droplets evaporate rapidly during desulfurization, wasting water resources and reducing desulfurization efficiency. Furthermore, flue gas carrying a large amount of saturated water vapor condenses rapidly into tiny droplets in the air after leaving the chimney, forming "chimney rain" or even "gypsum rain." Additionally, during denitrification, the insufficient mixing of ammonia and flue gas often reduces denitrification efficiency. Therefore, developing a cement kiln flue gas desulfurization and denitrification system that ensures thorough mixing of lime water and flue gas, reduces the flue gas desulfurization temperature, and achieves good desulfurization and denitrification effects is objectively necessary. Utility Model Content

[0004] The purpose of this invention is to provide a cement kiln flue gas desulfurization and denitrification system that can fully mix lime water with flue gas, reduce flue gas desulfurization temperature, and achieve good desulfurization and denitrification effects.

[0005] The purpose of this utility model is achieved as follows: It includes a denitrifier, a cooler, and a desulfurizer. The denitrifier contains a mixing chamber and multiple catalyst layers arranged sequentially from top to bottom. A flue gas inlet pipe and an ammonia inlet pipe are installed on the mixing chamber. A spiral channel is formed within the mixing chamber by a spiral plate, and a spiral tube is installed within the spiral channel. An air jet is installed on the spiral tube. The ammonia inlet pipe communicates with the spiral tube. A vent hole is located at the center of the bottom of the mixing chamber. The desulfurizer is divided from bottom to top into an inlet chamber and a desulfurizer by a partition. The reaction chamber has several air inlet pipes on the partition plate. The upper part of the reaction chamber has a liquid inlet chamber. The bottom of the liquid inlet chamber is rotatably connected to several bottom-sealed vertical pipes. Several nozzles are installed on the vertical pipes. Fan blades are installed at the bottom of the vertical pipes and are located inside the air inlet pipes. An air outlet pipe is installed on the side wall of the desulfurizer below the liquid inlet chamber. The lower part of the reaction chamber is connected to the middle part of the cooler through a liquid drain pipe. The bottom of the denitrifier is connected to the lower part of the cooler through a gas supply pipe. The top of the cooler is connected to the air inlet chamber through a pipeline.

[0006] Furthermore, the height of the drain pipe is lower than the height of the upper end of the upper air pipe.

[0007] Furthermore, a dehumidification chamber is provided inside the desulfurizer above the liquid inlet chamber, and the outlet end of the gas outlet pipe is tangentially connected to the side wall of the dehumidification chamber. An exhaust pipe is provided at the top of the dehumidification chamber.

[0008] Furthermore, a liquid inlet pipe is installed through the liquid inlet chamber, with the upper end of the liquid inlet pipe connected to the dehumidification chamber and the lower end extending into the lower part of the reaction chamber.

[0009] Furthermore, the lower part of the cooler is equipped with multiple interconnected concentric ring pipes, and the bottom of the concentric ring pipes is evenly provided with several spray holes, and the air supply pipe is connected to the concentric ring pipes.

[0010] Furthermore, the cooler is equipped with an air intake pipe that connects to the concentric ring pipe.

[0011] Furthermore, a gas distributor is installed in the denitrifier above each catalyst layer.

[0012] Furthermore, a condenser tube and a temperature sensor are installed in the upper part of the cooler.

[0013] Furthermore, an electrostatic precipitator is installed on the flue gas inlet pipe.

[0014] This invention is used for desulfurization and denitrification of flue gas from cement kilns. In operation, the flue gas is introduced into the mixing chamber of the denitrifier, where it flows along a spiral channel. Simultaneously, ammonia gas is introduced into the spiral tube through an ammonia inlet pipe. Subsequently, the ammonia gas is ejected from the nozzles on the spiral tube, mixing with the flue gas. During the spiral flow, the flue gas and ammonia gas continuously mix. The uniformly mixed gas is ejected from the vent holes and then flows sequentially through each catalyst layer, completing the denitrification process. The gas then flows into the cooler, where it reacts with the gases within. The desulfurization liquid comes into contact with the flue gas, cools and removes dust, and then flows into the inlet chamber of the desulfurizer. It is divided into multiple air streams, which flow into each of the upper air pipes, blowing the fan blades and causing them to rotate. The fan blades drive the vertical pipe to rotate, and then the flue gas flows into the reaction chamber. At the same time, the desulfurization liquid passes through the inlet chamber and the vertical pipe and is sprayed out through the nozzle. The sprayed desulfurization liquid droplets come into contact with the flue gas and remove sulfur dioxide from the flue gas through a neutralization reaction, thus completing the desulfurization of the flue gas. Finally, the dust removal, desulfurization and denitrification of the flue gas are completed, and the purified flue gas is discharged. In this invention, flue gas enters a spiral channel and flows spirally within it. Simultaneously, ammonia gas is ejected from nozzles on the spiral tube. The ammonia gas is injected into the flue gas at multiple points, providing initial mixing. Subsequently, the two gases mix uniformly during the spiral flow, solving the current problem of uneven mixing of ammonia and flue gas and improving the denitrification efficiency. Secondly, during desulfurization, the desulfurizing liquid is sprayed from nozzles on each vertical pipe. On one hand, the vertical pipes themselves are evenly distributed within the reaction chamber, ensuring uniform distribution of the sprayed droplets. On the other hand, the vertical pipes rotate under the drive of the fan blades, which in turn drives the nozzles to rotate, allowing the sprayed droplets to completely cover the entire reaction chamber, significantly increasing the spraying range. Furthermore, multiple streams of flue gas, after passing through the rotating fan blades, form multiple turbulent vortices. When the flue gas flows into the reaction chamber from the upper pipe, it expands and collides. In summary, this allows the lime water and other desulfurizing liquids to achieve uniform mixing. The sulfur solution can fully mix and react with the flue gas, solving the problem of insufficient mixing and reaction between flue gas and desulfurization solution in traditional desulfurization processes, thus improving the desulfurization effect. Furthermore, in this invention, after denitrification, the flue gas is passed into a cooler containing desulfurization solution. Passing the flue gas into the desulfurization solution serves two purposes: firstly, it performs preliminary desulfurization, reducing the workload of subsequent desulfurizers; secondly, it removes dust from the flue gas, preventing impurities such as dust from affecting desulfurization efficiency. Finally, the desulfurization solution cools the flue gas to a suitable temperature for desulfurization, while avoiding the problem of rapid evaporation of large amounts of desulfurization solution due to high flue gas temperature. This avoids water waste, improves desulfurization efficiency, and prevents the formation of "chimney rain" during flue gas discharge. Moreover, the cooling medium is the desulfurization solution that has already undergone desulfurization; passing the flue gas into it further consumes unreacted desulfurization solution, improving its utilization rate. In summary, this invention has the advantages of thorough mixing of lime water and flue gas, which can reduce the flue gas desulfurization temperature and achieve good desulfurization and denitrification effects. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of this utility model; In the diagram: 1-Denitrifier, 2-Cooler, 3-Desulfurizer, 4-Catalyst layer, 5-Spiral plate, 6-Spiral tube, 7-Reaction chamber, 8-Upper gas pipe, 9-Liquid inlet chamber, 10-Vertical pipe, 11-Fan blade, 12-Drain pipe, 13-Gas delivery pipe, 14-Dehumidification chamber, 15-Lower liquid pipe, 16-Concentric ring pipe, 17-Air inlet pipe, 18-Gas distributor, 19-Condenser, 20-Electrostatic precipitator, 21-Air inlet chamber. Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.

[0017] like Figure 1 As shown, this utility model includes a denitrifier 1, a cooler 2, and a desulfurizer 3. The denitrifier 1 has a mixing chamber and multiple catalyst layers 4 arranged sequentially from top to bottom. A flue gas inlet pipe and an ammonia inlet pipe are provided on the mixing chamber. A spiral channel is formed inside the mixing chamber by a spiral plate 5, and a spiral tube 6 is installed inside the spiral channel. An air jet is provided on the spiral tube 6. The ammonia inlet pipe is connected to the spiral tube 5. A vent hole is provided at the center of the bottom of the mixing chamber. The desulfurizer 3 is divided from bottom to top into an inlet chamber 21 and a reaction chamber 7 by a partition. Several air inlets are provided on the partition. The upper part of the reaction chamber 7 is provided with a liquid inlet chamber 9. The bottom of the liquid inlet chamber 9 is rotatably connected to several bottom-sealed vertical pipes 10. Several nozzles are provided on the vertical pipes 10. Fan blades 11 are provided at the bottom of the vertical pipes 10. The fan blades 11 are located in the corresponding upper air pipes 8. An air outlet pipe is provided on the side wall of the desulfurizer 3 below the liquid inlet chamber 9. The lower part of the reaction chamber 7 is connected to the middle part of the cooler 2 through the liquid drain pipe 12. The bottom of the denitrifier 1 is connected to the lower part of the cooler 2 through the air supply pipe 13. The top of the cooler 2 is connected to the air inlet chamber 21 through a pipeline.

[0018] This invention is used for desulfurization and denitrification of flue gas from cement kilns. In operation, flue gas is introduced into the mixing chamber of the denitrifier 1, and then flows along a spiral channel within the chamber. Simultaneously, ammonia gas is introduced into the spiral tube 6 from the ammonia inlet pipe. Subsequently, the ammonia gas is ejected from the nozzle on the spiral tube 6, mixing with the flue gas. During the spiral flow, the flue gas and ammonia gas continuously mix, and the uniformly mixed gas is ejected from the vent holes. It then flows sequentially through each catalyst layer 4, completing the denitrification of the flue gas. Finally, it flows into the cooler 2, contacting the desulfurization liquid within the cooler 2. The flue gas is cooled and dust removed, and then flows into the inlet chamber 21 of the desulfurizer 3. It is divided into multiple air streams, which flow into each of the upper air pipes 8, blowing the fan blades 11 and causing them to rotate. The fan blades 11 drive the vertical pipe 10 to rotate. Then the flue gas flows into the reaction chamber 7. At the same time, the desulfurization liquid passes through the liquid inlet chamber 9 and the vertical pipe 10 and is sprayed out through the nozzle. The sprayed desulfurization liquid droplets come into contact with the flue gas and remove sulfur dioxide from the flue gas through a neutralization reaction, thus completing the desulfurization of the flue gas. Finally, the dust removal, desulfurization and denitrification of the flue gas are completed, and the flue gas is discharged after purification.

[0019] In this invention, flue gas enters a spiral channel and flows spirally within it. Simultaneously, ammonia gas is ejected from the nozzles on the spiral tube 6. The ammonia gas is injected into the flue gas at multiple points, providing initial mixing. Subsequently, the two gases mix further during the spiral flow, achieving uniform mixing and solving the current problem of uneven mixing between ammonia and flue gas, thus improving the denitrification efficiency of the flue gas. Secondly, during desulfurization, the desulfurization liquid is sprayed from nozzles on each vertical pipe 10. On one hand, the vertical pipes 10 are evenly distributed within the reaction chamber 7, ensuring uniform distribution of the sprayed droplets. On the other hand, the vertical pipes 10 rotate under the drive of the fan blades 11, which in turn rotates the nozzles, allowing the sprayed droplets to completely cover the entire reaction chamber, significantly increasing the spray range. Furthermore, multiple streams of flue gas, after passing through the rotating fan blades 11, form multiple turbulent vortices. When the flue gas flows into the reaction chamber 7 from the upper gas pipe 8, it expands and collides. In summary, this... The desulfurization liquid, such as lime water, can fully mix and react with the flue gas, solving the problem of insufficient mixing and reaction between flue gas and desulfurization liquid in traditional desulfurization processes, thus improving the desulfurization effect. In addition, in this invention, after the flue gas completes denitrification, it is passed into cooler 2, which is filled with desulfurization liquid. Passing the flue gas into the desulfurization liquid allows for preliminary desulfurization of the flue gas, reducing the workload of the subsequent desulfurizer 3. On the other hand, the desulfurization liquid removes dust from the flue gas, preventing dust and other impurities in the flue gas from affecting the desulfurization efficiency. Finally, the desulfurization liquid cools the flue gas, reducing its temperature to a suitable level for desulfurization. This avoids the problem of rapid evaporation of large amounts of desulfurization liquid due to high flue gas temperature, thus avoiding water waste, improving desulfurization efficiency, and preventing the formation of "chimney rain" during flue gas discharge. Furthermore, since the cooling medium is the desulfurization liquid that has already undergone desulfurization, passing the flue gas into it can further consume unreacted desulfurization liquid, improving the utilization rate of the desulfurization liquid.

[0020] After the desulfurization liquid droplets react with the flue gas, they will fall to the bottom of the reaction chamber 7. If the liquid level is too high, it will fall into the air inlet chamber 21 through the upper air pipe 8. This process may affect the propulsion of the flue gas flow on the fan blade 11, reduce the speed of the fan blade 11, and thus affect the desulfurization efficiency. Therefore, the height of the drain pipe 12 is lower than the height of the upper end of the upper air pipe 8 to discharge the desulfurization liquid in time and prevent the desulfurization liquid from flowing into the upper air pipe 8.

[0021] A dehumidification chamber 14 is provided in the desulfurizer 3 above the liquid inlet chamber 9. The outlet end of the gas outlet pipe is tangentially connected to the side wall of the dehumidification chamber 14. An exhaust pipe is provided at the top of the dehumidification chamber 14. The flue gas after desulfurization contains a certain amount of moisture, which may contain a certain amount of sulfurous acid. It is tangentially introduced into the dehumidification chamber 14, and the centrifugal force is used to remove this moisture, thereby improving the purification effect of the flue gas and improving the utilization rate of water resources.

[0022] A liquid inlet pipe 15 is installed through the liquid inlet chamber 9. The upper end of the liquid inlet pipe 15 is connected to the dehumidification chamber 14, and the lower end extends into the lower part of the reaction chamber 7. The flue gas after desulfurization enters the dehumidification chamber 14 for dehumidification. The moisture will fall to the bottom of the dehumidification chamber 14, and then fall to the bottom of the reaction chamber 7 through the liquid inlet pipe 15 for collection and utilization.

[0023] The lower part of the cooler 2 is equipped with multiple interconnected concentric ring pipes 16. Several nozzles are evenly distributed at the bottom of each concentric ring pipe 16. The gas supply pipe 13 is connected to the concentric ring pipe 16. Flue gas enters the concentric ring pipe 16 through the gas supply pipe 13 and is then ejected from the nozzles at the bottom of the concentric ring pipe 16, dispersing the flue gas and ensuring it is evenly distributed in the desulfurization liquid within the cooler 2. This improves the initial desulfurization, dust removal, and cooling effects of the flue gas. The nozzles are located at the bottom of the concentric ring pipe 16 to prevent sediment in the desulfurization liquid from entering the concentric ring pipe 16 through the nozzles and causing blockage of the concentric ring pipe 16 or the nozzles.

[0024] The cooler 2 is equipped with an air inlet pipe 17 connected to the concentric ring pipe 16. This utility model adopts a wet desulfurization method, and the desulfurization liquid is an alkaline liquid such as lime water. During the desulfurization process, the desulfurization liquid reacts with sulfur dioxide in the flue gas to generate calcium sulfite, thereby removing sulfur dioxide from the flue gas. However, calcium sulfite is unstable, has low solubility, and is prone to scaling in the equipment, and its utilization value is not high. In this utility model, air is introduced into the desulfurization liquid discharged into the cooler 2. Since these desulfurization liquids participate in the desulfurization of flue gas and contain a large amount of calcium sulfite, the calcium sulfite is oxidized after air is introduced, thereby producing stable gypsum and improving its utilization value.

[0025] Each denitrifier 1 above the catalyst layer 4 is equipped with a gas distributor 18. The gas distributor 18 is an existing structure used to distribute the flue gas evenly, so that the flue gas is in uniform contact with the catalyst in the catalyst layer 4, thereby improving the flue gas denitrification effect.

[0026] The upper part of the cooler 2 is equipped with a condenser tube 19 and a temperature sensor. Flue gas is introduced into the cooler 2 and the desulfurization liquid is used to cool the flue gas. However, as the flue gas treatment process proceeds, the temperature of the desulfurization liquid will continue to rise, thereby reducing the cooling effect of the flue gas. The temperature sensor is used to detect the flue gas temperature. When the flue gas temperature is still too high and cannot meet the cooling requirements, a cooling medium can be introduced into the condenser tube 19 to further reduce the flue gas temperature and ensure that the flue gas temperature is suitable for subsequent desulfurization. At the same time, due to the high flue gas temperature, some of the desulfurization liquid will evaporate to form steam. The steam mixed into the flue gas may reduce the subsequent desulfurization effect. Therefore, the condenser tube 19 is set up. Water vapor condenses on the outer wall of the condenser tube 19, continuously accumulates and falls, thereby removing the steam in the flue gas.

[0027] An electrostatic precipitator 20 is installed on the flue gas inlet pipe. The electrostatic precipitator 20 is an existing dust removal device. Since the flue gas from cement kilns contains a large amount of dust and other impurities, these dusts will damage the catalyst layer 1 in the subsequent denitrification unit 1. Some of the impurities will also cause the catalyst layer 1 to deactivate. Therefore, before denitrifying the flue gas, using the electrostatic precipitator 20 to remove dust and other impurities from the flue gas is beneficial to improving the denitrification efficiency.

Claims

1. A desulfurization and denitrification system for cement kiln flue gas, comprising a denitrifier (1), a cooler (2), and a desulfurizer (3), characterized in that: The denitrifier (1) is provided with a mixing chamber and multiple catalyst layers (4) arranged sequentially from top to bottom. A flue gas inlet pipe and an ammonia inlet pipe are provided on the mixing chamber. A spiral channel is formed in the mixing chamber through a spiral plate (5). A spiral tube (6) is provided in the spiral channel. An air jet is provided on the spiral tube (6). The ammonia inlet pipe is connected to the spiral tube (6). A vent hole is provided at the center of the bottom of the mixing chamber. The desulfurizer (3) is divided into an inlet chamber (21) and a reaction chamber (7) from bottom to top by a partition. Several air inlet pipes (8) are provided on the partition. A liquid inlet chamber (9) is provided at the upper part of the reaction chamber (7). The bottom of the liquid inlet chamber (9) is sealed and rotatably connected to several bottom-sealed vertical pipes (10). Several nozzles are provided on the vertical pipes (10). Fan blades (11) are provided at the bottom of the vertical pipes (10). The fan blades (11) are located in the corresponding upper air pipes (8). An outlet pipe is provided on the side wall of the desulfurizer (3) below the liquid inlet chamber (9). The lower part of the reaction chamber (7) is connected to the middle part of the cooler (2) through the drain pipe (12). The bottom of the denitrifier (1) is connected to the lower part of the cooler (2) through the gas transmission pipe (13). The top of the cooler (2) is connected to the air inlet chamber (21) through a pipeline.

2. The desulfurization and denitrification system for cement kiln flue gas according to claim 1, characterized in that: The height of the drain pipe (12) is lower than the height of the upper end of the air pipe (8).

3. The desulfurization and denitrification system for cement kiln flue gas according to claim 1, characterized in that: A dehumidification chamber (14) is provided in the desulfurizer (3) above the liquid inlet chamber (9). The outlet end of the outlet pipe is tangentially connected to the side wall of the dehumidification chamber (14). An exhaust pipe is provided at the top of the dehumidification chamber (14).

4. The desulfurization and denitrification system for cement kiln flue gas according to claim 3, characterized in that: A liquid inlet pipe (15) is provided through the liquid inlet chamber (9). The upper end of the liquid inlet pipe (15) is connected to the dehumidification chamber (14), and the lower end extends into the lower part of the reaction chamber (7).

5. The desulfurization and denitrification system for cement kiln flue gas according to claim 1, characterized in that: The lower part of the cooler (2) is provided with a number of interconnected concentric ring pipes (16), and the bottom of the concentric ring pipes (16) is provided with a number of spray holes evenly distributed. The gas supply pipe (13) is connected to the concentric ring pipes (16).

6. The desulfurization and denitrification system for cement kiln flue gas according to claim 5, characterized in that: The cooler (2) is provided with an air intake pipe (17) that is connected to the concentric ring pipe (16).

7. The desulfurization and denitrification system for cement kiln flue gas according to claim 1, characterized in that: Each catalyst layer (4) is equipped with a gas distributor (18) in the denitrifier (1).

8. The desulfurization and denitrification system for cement kiln flue gas according to claim 1, characterized in that: The upper part of the cooler (2) is equipped with a condenser tube (19) and a temperature sensor.

9. The desulfurization and denitrification system for cement kiln flue gas according to claim 1, characterized in that: An electrostatic precipitator (20) is installed on the flue gas inlet pipe.

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