Anti-blocking device for air preheater of SCR denitration system

Abstract

The utility model belongs to flue gas treatment technical field, concretely relates to a kind of air preheater anti-blocking device of SCR denitration system, including storage feed system, metering conveying system, injection system and electric control system;The storage feed system is used to store desulfurizer, and desulfurizer is delivered to metering conveying system;The metering conveying system is used to weigh desulfurizer, and desulfurizer is delivered to injection system;The injection port of the injection system is arranged on the flue between SCR reactor inlet and SCR catalyst and rear air preheater.The air preheater anti-blocking device of the utility model is provided with injection port on the flue between SCR reactor inlet and SCR catalyst and rear air preheater, can remove SO3 in flue gas simultaneously before and after denitration reaction, maximizes the utilization of desulfurizer and the overall removal efficiency of SO3, to ensure the stable operation of entire flue gas treatment system.

Description

Technical Field

[0001] This utility model relates to the technical field of flue gas treatment equipment, specifically to an anti-clogging device for the air preheater of an SCR denitrification system. Background Technology

[0002] SCR denitrification systems are highly efficient at reducing nitrogen oxides (NOx) in industrial boilers, coal-fired power plants, and other applications. x The air preheater, a core environmental protection device for emissions control, often experiences blockage during long-term operation. The core mechanism behind this problem lies in the chemical reactions present in the flue gas: Since the flue gas itself contains SO3, and some SO2 is converted to SO3 under SCR catalysis, SO3 readily combines with ammonia (NH3) escaping from the denitrification system to form highly viscous ammonium bisulfate (ABS). When flue gas containing ABS enters the low-temperature section of the air preheater, the wall temperature is within the dew point range of ABS, causing it to rapidly condense and liquefy on the low-temperature wall surface, gradually accumulating and forming a sticky film similar to glue. This sticky film efficiently captures fly ash particles carried in the flue gas. After being adsorbed, the fly ash continuously accumulates and compacts, eventually forming a hard ash layer that gradually blocks the heat exchange channels and flue gas flow cross-section of the air preheater.

[0003] Once the air preheater of a denitrification system becomes clogged, it will trigger a series of chain problems: the system's flue gas resistance will increase sharply, leading to a significant increase in the energy consumption and insufficient output of the induced draft fan; the heat exchange efficiency will decrease severely, causing the boiler exhaust temperature to rise and the thermal efficiency to drop significantly; in extreme cases, the clog may also cause risks such as poor flue gas flow and localized overheating, posing a serious threat to the safe and stable operation of the boiler system. Therefore, effectively preventing and controlling the clogging of the air preheater in an SCR denitrification system is crucial to ensuring the stable operation of related environmental protection facilities and improving the energy efficiency and safety of the boiler system. Therefore, this application aims to solve this problem by providing an anti-clogging device for the air preheater of an SCR denitrification system. Utility Model Content

[0004] The purpose of this invention is to provide an anti-clogging device for the air preheater of an SCR denitrification system, addressing some shortcomings of existing technologies.

[0005] The technical solution of this utility model is: an anti-clogging device for an air preheater in an SCR denitrification system, comprising a storage and feeding system, a metering and conveying system, an injection system, and an electrical control system; the storage and feeding system, the metering and conveying system, and the injection system are all connected to the electrical control system and work together under the control of the electrical control system; the storage and feeding system is used to store the desulfurizing agent and transport the desulfurizing agent to the metering and conveying system; the metering and conveying system is used to weigh the desulfurizing agent and transport the desulfurizing agent to the injection system; the injection port of the injection system is set on the flue between the SCR reactor inlet and the SCR catalyst and the downstream air preheater.

[0006] Furthermore, the storage and feeding system includes a desulfurizing agent storage tank and a feeder; the top of the desulfurizing agent storage tank is equipped with a filter, and the tank is also equipped with a pressure vacuum release valve, a level gauge, and a fluidization device; the fluidization device includes a gasification blower, which is used to blow air into the desulfurizing agent storage tank to fluidize the desulfurizing agent powder and prevent blockage at the discharge port. A manual regulating valve and an electric heater are installed on the pipeline between the gasification blower and the desulfurizing agent storage tank to precisely control the flow rate and temperature of the fluidizing air generated by the gasification blower.

[0007] Furthermore, a manual gate valve is installed between the desulfurizing agent storage tank and the feeder. A flexible connection is used between the feeder and the weighing tank. This is because the feeder generates vibrations during operation; if a rigid pipe connection were used, these vibrations would be directly transmitted to the weighing tank. The sensors inside the weighing tank would respond to these vibrations, leading to inaccurate weight readings and severe fluctuations, making accurate measurement impossible.

[0008] Furthermore, the feeder is a frequency converter or a pneumatic feeder, used to adjust the feed rate according to the SO3 concentration in the flue gas to achieve continuous feeding.

[0009] Furthermore, the metering and conveying system includes a metering weighing tank, a rotary valve hopper, a continuous conveying pump, a conveying fan, and a conveying pipeline. The upper part of the metering weighing tank is equipped with a filter for removing air from the tank. Before operation, the metering weighing tank is zeroed and calibrated, and upper and lower weight limits are set. When the material reaches the upper limit, the feed valve is closed, and the material falls into the rotary valve hopper and flows in the conveying pipeline through the continuous conveying pump. When the material reaches the lower limit, the feed valve is opened to replenish the material.

[0010] Furthermore, the conveying blower can be one of a Roots blower, a centrifugal blower, or a high-pressure blower. A temperature sensor is installed at the outlet of the conveying blower, and pressure measuring holes are spaced apart on the conveying pipeline. A discharge valve is also provided on the conveying pipeline.

[0011] Furthermore, the injection system includes a high-efficiency distributor, a pneumatic regulating valve, and a desulfurizing agent spray gun. The high-efficiency distributor distributes the desulfurizing agent from the metering and delivery system to each branch, with the flow rate of each branch independently controlled by the pneumatic regulating valve, ultimately being injected into the flue gas duct through the desulfurizing agent spray gun. The injection system also includes a compressed air storage tank, which effectively smooths out pressure fluctuations in the delivery pipeline, providing a stable air source for the desulfurizing agent spray gun.

[0012] Furthermore, the nozzle of the desulfurizing agent spray gun is located at the inlet flue of the SCR reactor, and a sufficient distance is maintained between it and the SCR reaction catalyst so that the desulfurizing agent can fully combine with SO3.

[0013] Furthermore, the desulfurizing agent spray gun is an atomizing spray gun suitable for dry powder injection.

[0014] Furthermore, the desulfurizing agent is NaHCO3 or Na2CO3 powder.

[0015] Furthermore, the electronic control system is designed with a one-button start / stop function, which simplifies the operation of the entire air preheater anti-clogging device and improves safety.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows: The air preheater anti-clogging device of this utility model is equipped with injection ports on the inlet of the SCR reactor and the flue between the SCR catalyst and the downstream air preheater. It can simultaneously remove SO3 from the flue gas before and after the denitrification reaction, maximize the utilization rate of the desulfurizing agent and the overall SO3 removal efficiency, thereby ensuring the stable operation of the entire flue gas treatment system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present utility model; In the diagram: 1. Conveying fan; 2. Manual pipeline valve; 3. Pressure transmitter; 4. Continuous conveying pump; 5. Rotary valve hopper; 6. Weighing tank; 7. Flexible connection; 8. Variable frequency feeder; 9. Manual slide gate valve; 10. Discharge valve; 11. High-efficiency distributor; 12. Pneumatic regulating valve; 13. Desulfurizing agent spray gun; 14. Compressed air storage tank; 15. Gasification fan; 16. Manual regulating valve; 17. Electric heater; 18. Desulfurizing agent storage tank; 19. Filter. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments. Methods or functional components not specifically described in the embodiments are all prior art. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Example

[0019] like Figure 1 As shown, this embodiment is an anti-clogging device for the air preheater of an SCR denitrification system, including a storage and feeding system, a metering and conveying system, an injection system, and an electrical control system. The storage and feeding system, metering and conveying system, and injection system are all connected to the electrical control system and work together under the control of the electrical control system. The storage and feeding system is used to store the desulfurizing agent and transport it to the metering and conveying system. The metering and conveying system is used to weigh the desulfurizing agent and transport it to the injection system. The injection ports of the injection system are located at the inlet of the SCR reactor and on the flue between the SCR catalyst and the downstream air preheater.

[0020] In this embodiment, the storage and feeding system includes a desulfurizing agent storage tank 18 and a feeder. A filter 19 is installed on the top of the desulfurizing agent storage tank 18, which is also equipped with a pressure vacuum release valve, a level gauge, and a fluidization device. The fluidization device includes a gasification blower 15, which blows air into the desulfurizing agent storage tank 18 to fluidize the desulfurizing agent powder and prevent blockage at the discharge port. A manual regulating valve 16 and an electric heater 17 are installed on the pipeline between the gasification blower 15 and the desulfurizing agent storage tank 18 to precisely control the flow rate and temperature of the fluidizing air generated by the gasification blower 15.

[0021] In this embodiment, the feeder is a variable frequency feeder 8, and a manual gate valve 9 is installed between the desulfurizing agent storage tank 18 and the feeder. A flexible connection 7 connects the feeder and the weighing tank 6. This is because the feeder generates vibrations during operation; if a rigid pipe connection were used, these vibrations would be directly transmitted to the weighing tank 6. The sensors inside the weighing tank 6 would respond to these vibrations, leading to inaccurate weight readings and severe fluctuations, making accurate measurement impossible.

[0022] In this embodiment, the metering and conveying system includes a metering weighing tank, a rotary valve hopper 5, a continuous conveying pump 4, a conveying fan 1, and a conveying pipeline. The upper part of the metering weighing tank is equipped with a filter 19 for removing air from the tank. Before operation, the metering weighing tank is zeroed and calibrated, and upper and lower weight limits are set. When the material reaches the upper limit, the feed valve is closed, and the material falls into the rotary valve hopper 5 and flows in the conveying pipeline through the continuous conveying pump 4. When the material reaches the lower limit, the feed valve is opened to replenish the material.

[0023] In this embodiment, the conveying blower 1 is a Roots blower. A temperature sensor is installed at the outlet of the conveying blower 1. A manual pipeline valve 2 and a pressure transmitter 3 are also installed on the pipeline between the conveying blower 1 and the continuous conveying pump 4 to regulate the airflow of the conveying blower 1. A discharge valve 10 is provided on the conveying pipeline, and pressure measuring holes are also installed at intervals.

[0024] In this embodiment, the injection system includes a high-efficiency distributor 11, a pneumatic regulating valve 12, and a desulfurizing agent spray gun 13. The high-efficiency distributor 11 distributes the desulfurizing agent from the metering and conveying system to each branch, with the flow rate of each branch independently controlled by the pneumatic regulating valve 12, and the agent is finally injected into the flue gas duct through the desulfurizing agent spray gun 13. The injection system also includes a compressed air storage tank 14, which effectively smooths out pressure fluctuations in the conveying pipeline, providing a stable air source for the desulfurizing agent spray gun 13. The injection port of the desulfurizing agent spray gun 13, located at the inlet flue gas duct of the SCR reactor, maintains a sufficient distance from the SCR reaction catalyst to ensure that the desulfurizing agent fully combines with SO3.

[0025] In this embodiment, the desulfurizing agent spray gun 13 is an atomizing spray gun suitable for dry powder injection. The desulfurizing agent used is NaHCO3 or Na2CO3 powder. The electrical control system is designed with a one-button start / stop function, which can simplify the operation of the entire air preheater anti-clogging device.

[0026] In this embodiment, the desulfurizing agent storage tank 18 contains desulfurizing agent. The top filter 19 of the desulfurizing agent storage tank 18 is closed to prevent humid air from entering. To prevent the outlet of the desulfurizing agent storage tank 18 from being blocked by the desulfurizing agent, air is blown into the desulfurizing agent storage tank 18 by the gasification blower 15 to fluidize the desulfurizing agent powder, facilitating its smooth feeding. The material in the desulfurizing agent storage tank 18 is fed into the metering and weighing tank below by the feeder at the bottom of the desulfurizing agent storage tank 18. The metering and weighing tank is pre-zeroed and calibrated, and a certain upper and lower weight limit is set. When the feeding reaches the upper limit set by the metering and weighing tank, the feed valve is closed. The metering and weighing tank continuously feeds the material into the rotary valve hopper 5 below. The rotary valve rotates, causing the desulfurizing agent to fall into the conveying pipeline. Pressurized air is blown into the conveying pipeline by the conveying blower 1, so that the desulfurizing agent enters the desulfurizing agent spray gun 13 after passing through the high-efficiency distributor 11, and is injected into the flue by the desulfurizing agent spray gun 13, thereby fully reacting with SO3 in the flue gas.

[0027] The above are only some embodiments of the present utility model and are not intended to limit the present utility model. For those skilled in the art, the present utility model can have various combinations and modifications of the aforementioned technical features. Any improvements, modifications, equivalent substitutions, or applications of the structure or method of the present utility model to other fields to achieve the same effect without departing from the spirit and scope of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. An anti-clogging device for an air preheater in an SCR denitrification system, characterized in that: It includes a storage and feeding system, a metering and conveying system, a spraying system, and an electronic control system; the storage and feeding system, the metering and conveying system, and the spraying system are all connected to the electronic control system and work together under the control of the electronic control system; The storage and feeding system is used to store the desulfurizing agent and transport it to the metering and conveying system; The metering and conveying system is used to weigh the desulfurizing agent and convey it to the injection system; The injection ports of the injection system are located on the flue between the SCR reactor inlet and the SCR catalyst and the downstream air preheater. The injection system includes a high-efficiency distributor, a pneumatic regulating valve, and a desulfurizing agent spray gun; the high-efficiency distributor is used to distribute the desulfurizing agent from the metering and conveying system to each branch, and the flow rate of each branch is independently controlled by the pneumatic regulating valve, and finally injected into the flue through the desulfurizing agent spray gun; The nozzle of the desulfurizing agent spray gun is located at the inlet flue of the SCR reactor and a sufficient distance is maintained between it and the SCR reaction catalyst so that the desulfurizing agent can fully combine with SO3.

2. The anti-clogging device for the air preheater of the SCR denitrification system according to claim 1, characterized in that: The storage and feeding system includes a desulfurizing agent storage tank and a feeder; the top of the desulfurizing agent storage tank is equipped with a filter, and the desulfurizing agent storage tank is also equipped with a pressure vacuum release valve, a level gauge and a fluidization device; the fluidization device includes a gasification blower, which is used to blow air into the desulfurizing agent storage tank to fluidize the desulfurizing agent powder and prevent the discharge port from being blocked.

3. The anti-clogging device for the air preheater of the SCR denitrification system according to claim 2, characterized in that: The feeder is a frequency converter or a pneumatic feeder, used to adjust the feed rate according to the SO3 concentration in the flue gas to achieve continuous feeding.

4. The anti-clogging device for the air preheater of the SCR denitrification system according to claim 1, characterized in that: The metering and conveying system includes a metering weighing tank, a rotary valve hopper, a continuous conveying pump, a conveying fan, and a conveying pipeline. The upper part of the metering weighing tank is equipped with a filter for removing air from the tank. Before operation, the metering weighing tank is zeroed and calibrated, and upper and lower weight limits are set. When the material reaches the upper limit, the feed valve is closed, and the material falls into the rotary valve hopper and flows in the conveying pipeline through the continuous conveying pump. When the material reaches the lower limit, the feed valve is opened to replenish the material.

5. The anti-clogging device for the air preheater of the SCR denitrification system according to claim 4, characterized in that: The conveying fan is one of a Roots blower or a centrifugal blower. A temperature sensor is installed at the outlet of the conveying fan, and pressure measuring holes are installed at intervals on the conveying pipeline.

6. The anti-clogging device for the air preheater of the SCR denitrification system according to claim 1, characterized in that: The desulfurizing agent spray gun is an atomizing spray gun suitable for dry powder spraying.

7. The anti-clogging device for the air preheater of the SCR denitrification system according to claim 1, characterized in that: The desulfurizing agent is NaHCO3 or Na2CO3 powder.

Images