Low-temperature denitration equipment device used during start-stop peak regulation of power station boiler

Abstract

The invention belongs to the technical field of flue gas purification, and particularly relates to a low-temperature denitration equipment device during start-stop peak regulation of a power station boiler, the low-temperature denitration equipment device comprises an atomization flue and a plurality of spray guns, the spray guns are arranged at intervals in the radial direction of the atomization flue, and the distances between the outlet ends of the spray guns and the pipe wall of the atomization flue are different; an air inlet pipe and a liquid inlet pipe; the pressure adjusting module comprises a gas flow adjusting valve; flow meters and liquid flow regulating valves are arranged on the liquid inlet branch pipes; the gas inlet pipe is simultaneously communicated with gas inlets of all the spray guns on a downstream distribution pipeline of the gas flow regulating valve; and the control unit is respectively in signal connection with the gas flow regulating valve and each liquid flow regulating valve. The method has the innovation points that when the temperature of the flue gas is lower than 25-90 DEG C, the condensation phenomenon of equipment is avoided, the influence of increasing the humidity of the flue gas or low temperature on the denitration efficiency is avoided, the problem of nitrogen oxide escape is solved, efficient denitration under the low-temperature flue gas condition is realized, and the environmental protection emission index is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas purification, and particularly relates to a low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler. Background Art

[0002] Flue gas treatment is an indispensable link in industrial and energy production processes, and its main purpose is to reduce pollutant emissions and protect the environment and human health. Flue gas contains various harmful substances, including particulate matter, sulfur oxides, nitrogen oxides, heavy metals, volatile organic compounds, etc. At present, the following two methods are mainly used for denitration of flue gas from power station boilers: 1. SNCR (Selective Non-Catalytic Reduction): Ammonia or urea solution is sprayed into the boiler at a high temperature (850°C - 1050°C) for denitration. 2. SCR (Selective Catalytic Reduction): Ammonia or urea is sprayed at the outlet temperature of the boiler heat exchanger (300°C - 400°C), and then denitration is carried out through a solid catalyst bed. However, neither of the above two methods can solve the problem that nitrogen oxides cannot be effectively removed due to too low flue gas temperature during the start-up, shutdown and peak shaving of the boiler. Summary of the Invention

[0003] Aiming at the deficiencies of the above-mentioned existing technologies, the purpose of the present invention is to solve the problems that the existing SNCR / SCR technologies have high temperature requirements and cannot effectively solve the problem that nitrogen oxides cannot be effectively removed due to too low flue gas temperature during the start-up, shutdown and peak shaving of the boiler.

[0004] To achieve the above purpose, the present invention provides a low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler, including an atomizing flue connected to the flue between the smoke outlet of the power station boiler and the chimney;

[0005] A plurality of spray guns are arranged at intervals along the radial direction of the atomizing flue, and the distances between the outlet ends of the spray guns and the wall of the atomizing flue are different from each other;

[0006] An air inlet pipe for conveying compressed air;

[0007] A liquid inlet pipe for conveying a denitration agent;

[0008] A pressure regulation module, including:

[0009] A gas flow regulating valve arranged on the air inlet pipe;

[0010] A plurality of liquid inlet branch pipes, the inlet ends of which are connected in parallel to the liquid inlet pipe; a flow meter and a liquid flow regulating valve are sequentially arranged on each liquid inlet branch pipe; the outlet end of each liquid inlet branch pipe is connected to a corresponding one of the spray guns;

[0011] Wherein, the air inlet pipe is connected to the air inlets of all the spray guns through a gas distribution pipeline downstream of the gas flow regulating valve;

[0012] A control unit, which is respectively connected to the gas flow regulating valve and each of the liquid flow regulating valves by signals, is used to control the pressure of the compressed air main pipe by adjusting the opening degree of the gas flow regulating valve, and control the flow rate of the denitration agent delivered to each spray gun by independently adjusting the opening degree of each liquid flow regulating valve, so as to independently adjust the injection pressure of each spray gun.

[0013] Preferably, the denitration agent is obtained by mixing agent A and agent B through a drug mixer.

[0014] Preferably, agent A of the denitration agent includes acetic acid, sulfuric acid, and manganese sulfate, and agent B includes AEO-9, AES, polyaniline, dimethylformamide, and electrolyzed water.

[0015] Compared with the prior art, the advantages of the present invention are as follows:

[0016] The innovation of the present invention lies in ensuring that no condensation phenomenon occurs in the equipment when the flue gas temperature is lower than 25°C - 90°C by controlling the pressure distribution module in the process equipment, while avoiding increasing the flue gas humidity or the influence of low temperature on the denitration efficiency. The integrated control equipment includes sensors such as flow rate, temperature, air pressure, distributor, and flue gas flow rate, solves the problem of nitrogen oxide escape caused by too low flue gas temperature during boiler ignition startup, realizes efficient denitration under low-temperature flue gas conditions, and significantly improves the environmental protection emission index. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic flow chart when the present invention is applied in the power station boiler process;

[0018] Figure 2 is a schematic diagram of the pressure distribution module of the low-temperature denitration equipment device during start-up, shutdown, and peak shaving of a power station boiler provided by the present invention;

[0019] Figure 3 is a planar module diagram of the flue gas injection of the low-temperature denitration equipment device during start-up, shutdown, and peak shaving of a power station boiler provided by the present invention;

[0020] Figure 4 is a process route diagram of the control unit of the low-temperature denitration equipment device during start-up, shutdown, and peak shaving of a power station boiler provided by the present invention.

[0021] Among them, 1. Flue; 2. Spray gun; 3. Flue wall; 4. Intake pipe; 5. Liquid inlet pipe; 6. Gas flow regulating valve; 7. Liquid inlet branch pipe; 8. Liquid inlet pipe; 9. Flow meter; 10. Liquid flow regulating valve; 11. Liquid medicine mixer; 12. Boiler; 13. Air compressor; 14. Chimney; 15. Agent A; 16. Agent B; 17. SCR; 18. Denitration agent; 19. Compressed air; 20. Intake port; 21. Liquid inlet port; 22. Water tank. Detailed implementation mode

[0022] To make the purpose and principle of the present invention clearer, the following further elaborates in conjunction with the attached drawings and specific embodiments.

[0023] The present invention has been implemented in Jiangsu Huadian Kunshan Thermal Power Co., Ltd., and has passed engineering verification and expert review, reaching industrial-scale application. It mainly controls through integrated devices such as temperature sensors, gas pressure sensors, flue gas flow sensors, liquid sensors, gas density sensors, and resistance sensors installed at the tail of the flue, realizing precise coordination of temperature, liquid flow rate, pressure, and gas flow rate to adapt to the denitration process of low-temperature flue gas. This device is connected to the DCS automatic control system of the power plant, can precisely control the release and conversion of gas-liquid energy, significantly improve the denitration efficiency, and ensure compliance with environmental protection emissions standards.

[0024] Table 1: Original data of denitration without using the present invention;

[0025] Name Symbol Unit Data 1 Data 2 Average value Oxygen content O2 ％ 16.3 16.7 16.5 Sulfur dioxide SO2 mg / m3 5 8 6.5 Nitric oxide NO mg / m3 150.3 153.4 151.8 Nitrogen oxides NOx mg / m3 180.6 190.1 185.3

[0026] Table 2: Data after denitration using the device of the present invention;

[0027] Name Symbol Unit Data 1 Data 2 Average value Oxygen content O2 ％ 16.5 16.9 16.7 Sulfur dioxide SO2 mg / m3 4 3 3.5 Nitric oxide NO mg / m3 15.6 18.7 17.15 Nitrogen oxides NOx mg / m3 30.3 28.9 29.6

[0028] See Figure 1 , a low-temperature denitration equipment device for start-stop peak regulation of a power station boiler provided by the present invention includes an atomizing flue 1, a liquid medicine mixer 11, and a screw air compressor 13. After the flue gas is discharged from the boiler 12 and undergoes SCR denitration treatment, it enters the atomizing flue 1. The atomizing flue 1 is connected to the flue 1 between the smoke outlet of the power station boiler 12 and the chimney 14. The agent A 15 and the agent B 16 are mixed through the liquid medicine mixer 11 to obtain a denitration agent. The agent A 15 of the denitration agent includes acetic acid, sulfuric acid, and manganese sulfate, and the agent B 16 includes AEO-9, AES, polyaniline, dimethylformamide, and electrolyzed water. After the denitration agent is mixed with the compressed air in the screw air compressor, it enters the atomizing flue 1 for denitration, and finally is discharged from the chimney 14.

[0029] See Figure 2 , the pressure adjustment module in the present invention includes a gas flow regulating valve 6 provided on the intake pipe 4, and a plurality of liquid inlet branch pipes 7. The specific number of the liquid inlet branch pipes 7 can be selected according to actual conditions. The inlet ends of the liquid inlet branch pipes 7 are connected in parallel to the liquid inlet pipe 8. A flow meter 9 and a liquid flow regulating valve 10 are sequentially arranged on each liquid inlet branch pipe 7. At the same time, the intake pipe 4 is connected to the intake ports 20 of all spray guns 2 through a gas distribution pipeline downstream of the gas flow regulating valve 6.

[0030] See Figure 3, the atomizing flue 1 includes a plurality of spray guns 2, which are arranged at intervals along the radial direction of the atomizing flue 1. The outlet end of each liquid inlet branch pipe 7 in the pressure distribution module is connected to a corresponding spray gun 2, and the distances between the outlet ends of the spray guns 2 and the wall of the atomizing flue 1 are different. A liquid inlet 21 is arranged above the air inlet 20.

[0031] See Figure 4 , the control unit is respectively signal-connected to the gas flow regulating valve 6 and each liquid flow regulating valve 10, and is used to control the pressure of the compressed air main pipe by adjusting the opening degree of the gas flow regulating valve 6, and control the flow rate of the denitration agent delivered to each spray gun 2 by independently adjusting the opening degree of each liquid flow regulating valve 10, so as to independently adjust the spraying pressure of each spray gun 2.

[0032] Embodiment 1

[0033] This embodiment provides a low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler. The design variables of the pressure distribution module ensure that the equipment does not agglomerate when the flue gas temperature is lower than 25°C - 90°C, and the low temperature of the flue gas does not affect the denitration efficiency. The integrated control equipment includes sensors such as flow rate, temperature, air pressure, distributor, and flue gas flow rate.

[0034] The operation steps of the low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler provided in this embodiment in the actual process are as follows:

[0035] S1. Startup stage: When the boiler 12 is ignited and started, the integrated control equipment monitors parameters such as the flue gas temperature, pressure, and flow rate in real time.

[0036] S2: Denitration process: According to the sensor data, automatically adjust the gas-liquid energy release and conversion to ensure that nitrogen oxides in the low-temperature flue gas are effectively removed.

[0037] S3: Peak shaving stage: During the peak shaving process of the boiler 12, continuously monitor and adjust the equipment operation parameters to maintain high-efficiency denitration.

[0038] Embodiment 2

[0039] This embodiment provides a low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler. The pressure distribution module is optimized to ensure the stable operation of the equipment under extreme low-temperature conditions, enhance the low-temperature adaptability, avoid the increase of flue gas humidity, the integrated control equipment adds a gas density sensor to further improve the control accuracy, and the anti-corrosion supporting measures adopt PTFE spraying on the spray contact surface and pipe materials to specifically improve the anti-corrosion performance and meet the requirements of harsh working conditions.

[0040] The operation steps of the low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler provided in this embodiment in the actual process are as follows:

[0041] 1. Startup phase: When the boiler 12 is ignited and started, the integrated control device monitors parameters such as flue gas temperature, pressure, flow rate, and gas density in real time.

[0042] 2. Denitration process: According to the sensor data, the gas-liquid energy release and conversion are automatically adjusted to ensure that nitrogen oxides in the low-temperature flue gas are effectively removed.

[0043] 3. Peak shaving phase: During the peak shaving process of the boiler 12, the operation parameters of the equipment are continuously monitored and adjusted to maintain efficient denitration.

[0044] The above is only the specific implementation manner of this invention, but the protection scope of this invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by this invention, according to the technical solution and novel concept of this invention, makes equivalent substitutions or changes, and should be covered by the protection scope of this invention.

Claims

1. A low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler, characterized in that, include: Atomizing flue, which is connected to the flue between the smoke outlet and chimney of the power station boiler; A plurality of spray guns are arranged at intervals along the radial direction of the atomizing flue, and the distances between the outlet end of each spray gun and the wall of the atomizing flue are different; Inlet pipe, used to deliver compressed air; Liquid inlet pipe, used for transporting denitrification agent; Pressure regulation module, including: A gas flow regulating valve is provided on the air inlet pipe; A plurality of liquid inlet branch pipes, the inlet ends of which are connected in parallel to the liquid inlet pipe; each liquid inlet branch pipe is sequentially provided with a flow meter and a liquid flow regulating valve; the outlet end of each liquid inlet branch pipe is connected to a corresponding one of the spray guns; Wherein, the air inlet pipe is connected to the air inlets of all the spray guns simultaneously through a gas distribution pipeline downstream of the gas flow regulating valve; A control unit is respectively connected to the gas flow regulating valve and each of the liquid flow regulating valve signals, and is used to control the compressed air main pressure by adjusting the opening of the gas flow regulating valve, and to control the flow of denitrification agent delivered to each spray gun by independently adjusting the opening of each of the liquid flow regulating valves, thereby independently adjusting the injection pressure of each spray gun.

2. The low-temperature denitration equipment device during the start-up, shutdown and peak shaving of a power station boiler according to claim 1, characterized in that, The denitrification agent is obtained by mixing agent A and agent B through a drug mixer.

3. The low-temperature denitration equipment device during the start-up, shutdown and peak load regulation of a power station boiler according to claim 2, characterized in that, The denitrification agent A comprises acetic acid, sulfuric acid, and manganese sulfate, and the denitrification agent B comprises AEO-9, AES, polyaniline, dimethylformamide, and electrolyzed water.

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