Device for selective catalytic reduction and accurate denitration of flue gas of coal-fired boiler
By setting up an infrared temperature measurement system and an accurate denitrification controller on the coal-fired boiler, combined with mathematical models and real-time control, the precise denitrification of nitrogen oxides in the flue gas of the coal-fired boiler is achieved, solving the problem of denitrification instability caused by temperature changes, reducing costs and extending the catalyst life.
Patent Information
- Application Number
- CN202422494589.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2034-10-16
AI Technical Summary
In the prior art, the denitrification process of nitrogen oxides in the flue gas of coal-fired boilers has frequent temperature changes, resulting in unstable denitrification efficiency, increasing the use of denitrifier and shortening the catalyst life, making it difficult to achieve precise control.
The boiler infrared temperature measurement system and precise denitrification controller are adopted, combined with mathematical models and real-time control, and dynamically adjust the ammonia injection point and denitrification reaction temperature range to ensure that the denitrification reaction is carried out within the optimal temperature range. Through the precise switching of multiple denitrification flues and electric baffle doors, the precise control of the ammonia injection point is achieved.
It improves the stability of denitrification efficiency, reduces the cost of denitrition agent, extends the service life of the catalyst, has strong adaptability and flexible regulation.
Smart Images
Figure CN223299808U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a device for precise denitration of flue gas from a coal-fired boiler by selective catalytic reduction, and in particular to a device for precise denitration of flue gas from a coal-fired boiler, in which a boiler furnace flue gas infrared temperature measurement system, a boiler top convection heating zone flue gas infrared temperature measurement system and a precise denitration controller are respectively arranged on the boiler body, and precise denitration sub-controllers A, B, C, electric baffle doors A, B, C, ammonia spray guns A, B, C and a denitration catalyst layer are respectively arranged on the denitration flue ducts A, B, C. Background Art
[0002] Selective catalytic reduction (SCR) denitrification (DNO) often uses high-temperature catalysts and ammonia as the reducing agent. The optimal temperature range for the ammonia injection point and the reaction between ammonia and nitrogen oxides under the action of the high-temperature catalyst generally lies between 315°C and 400°C. In actual operation, due to the complexity of the coal combustion process and the evolution of characteristic parameters such as flue gas temperature, the ammonia injection point in the flue and the temperature range in which the denitrification reaction occurs frequently change. This significantly impacts the effective removal of nitrogen oxides from the flue gas, significantly increases the amount of denitrification reducing agent used, and negatively impacts the service life of the denitrification catalyst. The accuracy of SCR DNO has gradually become a hot topic in basic research and technological development.
[0003] The utility model is based on long-term data collection, modeling and analysis and demonstration, combined with continuous optimization of engineering practice experience, and according to the characteristics and laws of the coal combustion process and the evolution of flue gas temperature, adopts the process design principle of real-time control and precise switching, so that the ammonia injection point and the denitrification reaction are always in the optimal temperature range, thereby ensuring the accuracy and effectiveness of selective catalytic reduction denitrification, improving the long-term stability of denitrification efficiency, greatly saving the cost of using denitrification reducing agents, and significantly extending the service life of denitrification catalysts. The utility model has wide process adaptability and strong accuracy of dynamic adjustment. Summary of the Invention
[0004] The purpose of the present invention is to provide a device for selective catalytic reduction and precise denitrification of flue gas from a coal-fired boiler, which comprises a boiler furnace flue gas infrared temperature measurement system, a boiler top convection heating zone flue gas infrared temperature measurement system, and a precise denitrification controller, respectively, disposed on the boiler body; a precise denitrification sub-controller A, a precise denitrification sub-controller B, and a precise denitrification sub-controller C, electric damper doors A, electric damper doors B, and electric damper doors C, ammonia spray guns A, ammonia spray guns B, and ammonia spray guns C, and a denitrification catalyst layer, respectively. The utility model adopts a process design principle of real-time control and precise switching, so that the ammonia injection point and the denitrification reaction are always within the optimal temperature range, thereby ensuring the precision and effectiveness of selective catalytic reduction denitrification, improving the long-term stability of denitrification efficiency, significantly saving the cost of using denitrification reducing agents, and significantly extending the service life of denitrification catalysts. The utility model has wide process adaptability and high precision of dynamic adjustment.
[0005] To achieve these objectives, the present invention incorporates a boiler furnace flue gas infrared temperature measurement system, a boiler top convection heating zone flue gas infrared temperature measurement system, and a precision denitrification controller on the boiler body. The boiler furnace flue gas infrared temperature measurement system measures and dynamically acquires flue gas temperature data and dynamic distribution on the BB' section of the boiler's combustion zone in real time, and transmits this data to the precision denitrification controller in real time. The boiler top convection heating zone flue gas infrared temperature measurement system measures and dynamically acquires flue gas temperature data and dynamic distribution on the AA' section of the boiler's convection heating zone in real time, and transmits this data to the precision denitrification controller in real time.
[0006] In order to achieve the above-mentioned purpose, the precise denitrification controller of the present invention obtains the real-time flue gas temperature data and dynamic distribution on the AA' section and the BB' section, and then combines the input and dynamically adjusted fuel, boiler body coal combustion characteristics, boiler and flue dimensions, water-cooled wall and heat exchange surface, system air leakage rate and other data, through real-time simulation calculation and dynamic optimization adjustment of mathematical models and control programs, and finally obtains the temperature range distribution data in the boiler tail high-temperature flue, providing a precise control basis for the precise setting of the denitrification flue on the boiler tail high-temperature flue.
[0007] To achieve the above objectives, the utility model sequentially arranges denitrification flue A, denitrification flue B, and denitrification flue C on the high-temperature flue at the rear of the boiler. The vertical distance between the centerline of denitrification flue A and the AA' section of the convection heating zone at the top of the boiler is 6 meters, the vertical distance between the centerline of denitrification flue B and the AA' section of the convection heating zone at the top of the boiler is 13 meters, and the vertical distance between the centerline of denitrification flue C and the AA' section of the convection heating zone at the top of the boiler is 19.5 meters.
[0008] To achieve the above objectives, the present invention provides a precise denitrification sub-controller A on the denitrification flue A, a precise denitrification sub-controller B on the denitrification flue B, and a precise denitrification sub-controller C on the denitrification flue C. Precision denitrification sub-controller A, precision denitrification sub-controller B, and precision denitrification sub-controller C all operate under the control of the precise denitrification controller.
[0009] To achieve the above objectives, the present invention provides electric damper doors A, B, and C at the entrances of denitrification flue A, denitrification flue B, and denitrification flue C, respectively. When electric damper door A is open and electric damper doors B and C are closed, flue gas enters denitrification flue A, where nitrogen oxides in the flue gas are removed. When electric damper door B is open and electric damper doors A and C are closed, flue gas enters denitrification flue B, where nitrogen oxides in the flue gas are removed. When electric damper door C is open and electric damper doors A and B are closed, flue gas enters denitrification flue C, where nitrogen oxides in the flue gas are removed.
[0010] To achieve the above purpose, the utility model sets an ammonia spray gun A on the denitrification flue A to spray ammonia, a denitrification reducing agent, into the denitrification flue A. The ammonia spray gun A is connected to an ammonia-air mixer, and the ammonia-air mixer is connected to a liquid ammonia storage tank.
[0011] To achieve the above purpose, the present invention sets an ammonia spray gun B on the denitrification flue B, which is used to spray ammonia, a denitrification reducing agent, into the denitrification flue B. The ammonia spray gun B is connected to an ammonia-air mixer, which is connected to a liquid ammonia storage tank.
[0012] To achieve the above purpose, the utility model sets an ammonia spray gun C on the denitrification flue C to spray ammonia, a denitrification reducing agent, into the denitrification flue C. The ammonia spray gun C is connected to an ammonia-air mixer, and the ammonia-air mixer is connected to a liquid ammonia storage tank.
[0013] To achieve the above objectives, the ammonia-air mixer of the present invention is used to mix ammonia and air, with the volume ratio of ammonia to air (ammonia-air mixing ratio) in the mixed gas controlled within 5%. A liquid ammonia storage tank is used to supply ammonia to the ammonia-air mixer.
[0014] In order to achieve the above-mentioned purpose, the utility model provides a denitrification catalyst layer in the denitrification flue A, the denitrification flue B and the denitrification flue C. The catalyst in the denitrification catalyst layer adopts a high-temperature catalyst, and the type is honeycomb, plate or corrugated. The chemical composition of the catalyst is TiO2 as the carrier and the active ingredient is V2O5.
[0015] After automatic analysis and judgment by the precise denitrification controller of the present invention, when the center line of the denitrification flue A is in the temperature range of 355℃~385℃, the precise denitrification controller sends control signals to the precise denitrification sub-controller A, the precise denitrification sub-controller B and the precise denitrification sub-controller C respectively. Under the control of the precise denitrification sub-controller A, the electric damper door A is opened and the ammonia spray gun A is put into use. Under the control of the precise denitrification sub-controller B, the electric damper door B is closed and the ammonia spray gun B is deactivated. Under the control of the precise denitrification sub-controller C, the electric damper door C is closed and the ammonia spray gun C is deactivated. At this time, the flue gas enters the denitrification flue A, and the nitrogen oxides in the flue gas are removed in the denitrification flue A.
[0016] After automatic analysis and judgment by the precise denitrification controller of the present invention, when the center line of the denitrification flue B is in the temperature range of 355℃~385℃, the precise denitrification controller sends control signals to the precise denitrification sub-controller A, the precise denitrification sub-controller B and the precise denitrification sub-controller C respectively. Under the control of the precise denitrification sub-controller B, the electric damper door B is opened and the ammonia spray gun B is put into use. Under the control of the precise denitrification sub-controller A, the electric damper door A is closed and the ammonia spray gun A is deactivated. Under the control of the precise denitrification sub-controller C, the electric damper door C is closed and the ammonia spray gun C is deactivated. At this time, the flue gas enters the denitrification flue B, and the nitrogen oxides in the flue gas are removed in the denitrification flue B.
[0017] After automatic analysis and judgment by the precise denitrification controller of the present invention, when the center line of the denitrification flue C is at a temperature range of 355°C to 385°C, the precise denitrification controller sends control signals to the precise denitrification sub-controller A, the precise denitrification sub-controller B and the precise denitrification sub-controller C respectively. Under the control of the precise denitrification sub-controller C, the electric damper door C opens and the ammonia spray gun C is put into use. Under the control of the precise denitrification sub-controller A, the electric damper door A closes and the ammonia spray gun A is deactivated. Under the control of the precise denitrification sub-controller B, the electric damper door B closes and the ammonia spray gun B is deactivated. At this time, the flue gas enters the denitrification flue C and the nitrogen oxides in the flue gas are removed in the denitrification flue C.
[0018] Compared with the prior art, the present invention has the following features:
[0019] (1) This utility model is based on long-term data collection, modeling and analysis and demonstration, combined with continuous optimization of engineering practice experience, and in accordance with the characteristics and laws of the coal combustion process and flue gas temperature evolution, adopts the process design principle of real-time control and precise switching, so that the ammonia injection point and the denitrification reaction are always in the optimal temperature range, thereby ensuring the accuracy and effectiveness of selective catalytic reduction denitrification, improving the long-term stability of denitrification efficiency, and being suitable for the actual situation of flue gas denitrification in my country with variable working conditions, with strong load adaptability and flexible working condition adjustment.
[0020] (2) The utility model can greatly save the cost of using denitrification reducing agent and significantly extend the service life of denitrification catalyst.
[0021] (3) The process of this utility model has wide adaptability and high precision of dynamic adjustment.
[0022] (4) This utility model patent has the characteristics of convenient inspection and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The present invention will be described in further detail below with reference to the accompanying drawings.
[0024] Figure 1 It is a schematic diagram of the process flow of this utility model patent.
[0025] Figure: 1. Boiler body, 2. Boiler tail high-temperature flue, 3-A. Denitrification flue A, 3-B. Denitrification flue B, 3-C. Denitrification flue C, 4. Vertical low-temperature flue, 5. Horizontal low-temperature flue, 6. Denitrification catalyst layer, 7. Boiler furnace flue gas infrared temperature measurement system, 8. Boiler top convection heating zone flue gas infrared temperature measurement system, 9. Precision denitrification controller, 10. Precision denitrification sub-controller A, 11. Precision denitrification sub-controller B, 12. Precision denitrification sub-controller C, 13. Electric damper door A, 14. Electric damper door B, 15. Electric damper door C, 16. Ammonia spray gun A, 17. Ammonia spray gun B, 18. Ammonia spray gun C, 19. Ammonia-air mixer, 20. Liquid ammonia storage tank. DETAILED DESCRIPTION
[0026] Figure 1In the embodiment, a boiler furnace flue gas infrared temperature measurement system (7), a boiler top convection heating zone flue gas infrared temperature measurement system (8) and a precise denitrification controller (9) are respectively arranged on the boiler body (1); a precise denitrification sub-controller A (10), a precise denitrification sub-controller B (11) and a precise denitrification sub-controller C (12), an electric damper door A (13), an electric damper door B (14) and an electric damper door C (15), an ammonia spray gun A (16), an ammonia spray gun B (17) and an ammonia spray gun C (18) and a denitrification catalyst layer (6) are respectively arranged on the denitrification flue A (3-A), the denitrification flue B (3-B) and the denitrification flue C (3-C).
[0027] After automatic analysis and judgment by the precise denitrification controller (9) of the present invention, when the center line of the denitrification flue A (3-A) is located in the temperature range of 355°C to 385°C, the precise denitrification controller (9) sends control signals to the precise denitrification sub-controller A (10), the precise denitrification sub-controller B (11) and the precise denitrification sub-controller C (12) respectively. Under the control of the precise denitrification sub-controller A (10), the electric damper door A (13) is opened, and the ammonia spray gun A (16) is put into use. Under the control of the precise denitrification sub-controller B (11), the electric damper door B (14) is closed, and the ammonia spray gun B (17) is deactivated. Under the control of the precise denitrification sub-controller C (12), the electric damper door C (15) is closed, and the ammonia spray gun C (18) is deactivated. At this time, the flue gas enters the denitrification flue A (3-A), and the nitrogen oxides in the flue gas are removed in the denitrification flue A (3-A).
[0028] After automatic analysis and judgment by the precise denitrification controller of the present invention, when the center line of the denitrification flue B (3-B) is in the temperature range of 355°C to 385°C, the precise denitrification controller (9) sends control signals to the precise denitrification sub-controller A (10), the precise denitrification sub-controller B (11) and the precise denitrification sub-controller C (12) respectively. Under the control of the precise denitrification sub-controller B (11), the electric damper door B (14) is opened, and the ammonia spray gun B (17) is put into use. Under the control of the precise denitrification sub-controller A (10), the electric damper door A (13) is closed, and the ammonia spray gun A (16) is deactivated. Under the control of the precise denitrification sub-controller C (12), the electric damper door C (15) is closed, and the ammonia spray gun C (18) is deactivated. At this time, the flue gas enters the denitrification flue B (3-B), and the nitrogen oxides in the flue gas are removed in the denitrification flue B (3-B).
[0029] After automatic analysis and judgment by the precise denitrification controller of the present invention, when the center line of the denitrification flue C (3-C) is in the temperature range of 355°C to 385°C, the precise denitrification controller (9) sends control signals to the precise denitrification sub-controller A (10), the precise denitrification sub-controller B (11) and the precise denitrification sub-controller C (12) respectively. Under the control of the precise denitrification sub-controller C (12), the electric damper door C (15) is opened, and the ammonia spray gun C (18) is put into use. Under the control of the precise denitrification sub-controller A (10), the electric damper door A (13) is closed, and the ammonia spray gun A (16) is deactivated. Under the control of the precise denitrification sub-controller B (11), the electric damper door B (14) is closed, and the ammonia spray gun B (17) is deactivated. At this time, the flue gas enters the denitrification flue C (3-C), and the nitrogen oxides in the flue gas are removed in the denitrification flue C (3-C).
[0030] The ammonia-air mixer (19) of the present invention mixes ammonia and air, and the volume ratio of ammonia to air in the mixed gas (ammonia-air mixing ratio) is controlled within 5%. The liquid ammonia storage tank (20) is used to supply ammonia to the ammonia-air mixer.
[0031] The catalyst in the denitration catalyst layer (6) of the utility model adopts a high-temperature catalyst, which is in the form of a honeycomb type, a plate type or a corrugated type. The chemical composition of the catalyst is based on TiO2 as a carrier and the active component is V2O5.
[0032] The above is only a specific implementation of the present invention, and the technical features of the present invention are not limited thereto. Any changes or modifications made by any technician in this field within the scope of the present invention should be included in the patent scope of the present invention.
Claims
1. A device for precise denitration of coal-fired boiler flue gas by selective catalytic reduction, comprising a boiler furnace flue gas infrared temperature measurement system, a boiler top convection heating zone flue gas infrared temperature measurement system, a precise denitration controller, denitration flue A, denitration flue B, denitration flue C, precise denitration sub-controller A, precise denitration sub-controller B, precise denitration sub-controller C, electric baffle door A, electric baffle door B, electric baffle door C, ammonia spray guns A, ammonia spray guns B, ammonia spray guns C, and a denitration catalyst layer, characterized in that: The boiler body is respectively provided with a boiler furnace flue gas infrared temperature measurement system, a boiler top convection heating zone flue gas infrared temperature measurement system and a precise denitrification controller; the denitrification flue A, denitrification flue B and denitrification flue C are sequentially provided on the high-temperature flue at the rear of the boiler; the denitrification flue A is provided with a precise denitrification sub-controller A, an electric damper door A, an ammonia spray gun A and a denitrification catalyst layer; the denitrification flue B is provided with a precise denitrification sub-controller B, an electric damper door B, an ammonia spray gun B and a denitrification catalyst layer; the denitrification flue C is provided with a precise denitrification sub-controller C, an electric damper door C, an ammonia spray gun C and a denitrification catalyst layer.
2. The device for selective catalytic reduction of coal-fired boiler flue gas according to claim 1 is characterized in that: When the center line of the denitrification flue A is in the temperature range of 355℃~385℃, the precise denitrification controller sends control signals to the precise denitrification sub-controller A, the precise denitrification sub-controller B and the precise denitrification sub-controller C respectively. Under the control of the precise denitrification sub-controller A, the electric damper door A opens and the ammonia spray gun A is put into use. Under the control of the precise denitrification sub-controller B, the electric damper door B closes and the ammonia spray gun B is deactivated. Under the control of the precise denitrification sub-controller C, the electric damper door C closes and the ammonia spray gun C is deactivated. At this time, the flue gas enters the denitrification flue A and the nitrogen oxides in the flue gas are removed in the denitrification flue A.
3. The device for selective catalytic reduction of coal-fired boiler flue gas according to claim 1 is characterized in that: When the center line of the denitrification flue B is in the temperature range of 355℃~385℃, the precise denitrification controller sends control signals to the precise denitrification sub-controller A, the precise denitrification sub-controller B and the precise denitrification sub-controller C respectively. Under the control of the precise denitrification sub-controller B, the electric damper door B opens and the ammonia spray gun B is put into use. Under the control of the precise denitrification sub-controller A, the electric damper door A closes and the ammonia spray gun A is deactivated. Under the control of the precise denitrification sub-controller C, the electric damper door C closes and the ammonia spray gun C is deactivated. At this time, the flue gas enters the denitrification flue B and the nitrogen oxides in the flue gas are removed in the denitrification flue B.
4. The device for selective catalytic reduction of coal-fired boiler flue gas according to claim 1, characterized in that: When the center line of the denitrification flue C is in the temperature range of 355℃~385℃, the precise denitrification controller sends control signals to the precise denitrification sub-controller A, the precise denitrification sub-controller B and the precise denitrification sub-controller C respectively. Under the control of the precise denitrification sub-controller C, the electric damper door C opens and the ammonia spray gun C is put into use. Under the control of the precise denitrification sub-controller A, the electric damper door A closes and the ammonia spray gun A is deactivated. Under the control of the precise denitrification sub-controller B, the electric damper door B closes and the ammonia spray gun B is deactivated. At this time, the flue gas enters the denitrification flue C and the nitrogen oxides in the flue gas are removed in the denitrification flue C.