Converter secondary dust removal flue gas cooling system and method

Abstract

The present application relates to a kind of converter secondary dust removal flue gas cooling system and method, one end of flue gas main pipeline is connected with the input end of secondary dust collector, the other end of flue gas main pipeline is communicated with the one end of flue gas branch pipeline one, the one end of flue gas branch pipeline two respectively, the other end of flue gas branch pipeline one is connected with the one end of dust cover by communicating pipe one, the other end of flue gas branch pipeline two is connected with the other end of dust cover by communicating pipe two;Flue gas main pipeline, flue gas branch pipeline one, flue gas branch pipeline two are all provided with gas mist spray gun, and the number of gas mist spray gun is ≥1.The present application has the advantages that: the temperature of secondary dust removal main pipeline and flue gas branch pipeline is collected, multi-stage cooling is used for different flue gas temperature, flue gas temperature control is realized, flue gas temperature is always kept in reasonable range, the risk of burning loss of dust cloth bag or filter cartridge is reduced, dust removal system stable operation is realized, and high-efficiency low-cost operation of dust removal system is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of environmental protection equipment for converters in steel plants, and in particular to a converter secondary dust removal flue gas cooling system and method. Background Technology

[0002] During the production of top-bottom combined injection converters in domestic steel enterprises, a large amount of high-temperature, high-dust gas is generated. In the dust removal systems of various areas of the converter, the dust removal system responsible for collecting the flue gas generated during the processes of ferroalloy charging, scrap steel addition, steel tapping, and slag removal is called "secondary dust removal." The secondary dust removal system also collects the flue gas overflowing from the primary dust removal system. Secondary dust removal uses a sealed smoke box to collect the flue gas generated at each stage of converter production and is an important environmental protection device in converter production. However, in practical applications, during the ferroalloy charging process, a large amount of high-temperature combustible gas is generated and burns at the furnace mouth, or large splashes occur during the converter smelting process, causing a rapid rise in flue gas temperature. Conventional secondary dust collectors cannot effectively control the flue gas temperature. After the high-temperature flue gas enters the secondary dust collector, a large number of filter bags or cartridges inside the secondary dust collector are burned due to heat, leading to a decline in dust collector performance and failure to meet emission standards for particulate matter. Summary of the Invention

[0003] The purpose of this invention is to provide a converter secondary dust removal flue gas cooling system and method to solve the problems that occur during converter production, when a large amount of high-temperature combustible gas is generated during iron charging and smelting, or when large splashes occur during the converter smelting process, causing the temperature of the secondary dust removal system to rise rapidly, the flue gas temperature to flue uncontrollably and large fluctuations, resulting in the burning of filter bags or filter cartridges in the dust collector, the decline in dust removal performance of the dust collector, and production shutdown. This invention ensures that the dust removal system operates with high efficiency and low cost.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A converter secondary dust removal flue gas cooling system includes a dust removal fan, a secondary dust collector, and a dust removal hood. The dust removal hood is installed above the converter's front door. The output end of the dust removal fan is connected to the chimney, and the input end of the dust removal fan is connected to the output end of the secondary dust collector. The system also includes a main flue gas duct, a first flue gas branch duct, a second flue gas branch duct, a cooling water duct, and a compressed air duct. One end of the main flue gas duct is connected to the input end of the secondary dust collector, and the other end of the main flue gas duct is connected to one end of the first flue gas branch duct and one end of the second flue gas branch duct. The other end of the first flue gas branch duct is connected to one end of the dust removal hood through a connecting pipe, and the other end of the second flue gas branch duct is connected to the other end of the dust removal hood through a connecting pipe.

[0006] Each of the main flue gas duct, flue gas branch duct 1, and flue gas branch duct 2 is equipped with an aerosol spray gun. The number of aerosol spray guns is ≥1 set, and each set contains several aerosol spray guns. One end of the cooling water pipe is connected to the water inlet pipe of the aerosol spray gun, one end of the compressed air pipe is connected to the air inlet pipe of the aerosol spray gun, the other end of the cooling water pipe is connected to a water source, and the other end of the compressed air pipe is connected to an air source.

[0007] The aerosol spray gun includes a nozzle and a spray gun body. The nozzle is provided with multiple water outlets, and a connecting flange is provided at the junction of the nozzle and the spray gun body. The connecting flange is used to fix the aerosol spray gun to the flue gas duct.

[0008] Dust removal valve 1 before the furnace and dust removal valve 1 after the furnace are installed sequentially on connecting pipe 1, and dust removal valve 2 before the furnace and dust removal valve 2 after the furnace are installed sequentially on connecting pipe 2.

[0009] A dust collector inlet thermocouple, a mixing valve 1, a mixing valve 2, and a flue gas main duct inlet thermocouple are sequentially installed at the input end of the flue gas main duct near the secondary dust collector. The dust collector inlet thermocouple is used to detect the flue gas temperature T4 at the dust collector inlet. The flue gas main duct inlet thermocouple is used to detect the flue gas temperature T1 in the secondary dust collector main duct. A flue gas branch pipe thermocouple 1 is installed on flue gas branch pipe 1, and a flue gas branch pipe thermocouple 2 is installed on flue gas branch pipe 2. The flue gas branch pipe thermocouple 1 is used to detect the flue gas temperature T2 in flue gas branch pipe 1, and the flue gas branch pipe thermocouple 2 is used to detect the flue gas temperature T3 in flue gas branch pipe 2. A water flow meter, a cooling water regulating valve, and a water shut-off valve are sequentially installed on the cooling water duct. A compressed air shut-off valve is installed on the compressed air duct.

[0010] The flue gas branch thermocouple 1, flue gas branch thermocouple 2, water flow meter, cooling water regulating valve, water shut-off valve, compressed air shut-off valve, dust collector inlet thermocouple, mixing valve 1, mixing valve 2, and flue gas main pipe inlet thermocouple are respectively connected to the control unit.

[0011] The control unit is a PLC. The flue gas branch thermocouple 1, flue gas branch thermocouple 2, water flow meter, dust collector inlet thermocouple, and flue gas main pipe inlet thermocouple are connected to the PLC input terminal through ports. The cooling water regulating valve, water shut-off valve, compressed air shut-off valve, mixing valve 1, and mixing valve 2 are connected to the PLC output terminal through ports.

[0012] A method for cooling flue gas from a converter's secondary dust removal system includes:

[0013] In a temperature rise and fall cycle, 1) during temperature rise:

[0014] When the flue gas temperature in the secondary dust removal main duct is T1 > 150℃, both mixing valve one and mixing valve two are fully opened, and the air mixed in by mixing valve one and mixing valve two cools the secondary flue gas.

[0015] When the flue gas temperature T1 in the secondary dust removal main duct is greater than 250℃, the aerosol spray guns installed in the main flue gas duct are turned on sequentially. The water flow rate of the aerosol spray guns in the main flue gas duct is between 3 and 5 m³ / h. 3 Between / h, and if the flue gas temperature T2 in flue gas branch duct 1 is >450℃, turn on the aerosol spray gun in flue gas branch duct 1, and set the water flow rate to 4-5m³ / h. 3 / h; When T3 > 450℃, turn on the aerosol spray gun in flue gas branch pipe 2, and set the water flow rate to 4-5m³ / h. 3 Between / h;

[0016] 2) During cooling;

[0017] When the flue gas temperature T1 in the secondary dust removal main duct is ≤300℃, close the aerosol spray guns in flue gas branch duct one, flue gas branch duct two, and one-third of the aerosol spray guns installed in the flue gas main duct.

[0018] When the flue gas temperature T1 in the secondary dust removal main duct is ≤170℃, close one-third (rounded) of the number of aerosol spray guns installed in the main flue gas duct.

[0019] When the flue gas temperature T1 in the secondary dust removal main duct is ≤160℃, shut down the remaining aerosol spray guns installed in the flue gas main duct.

[0020] If the flue gas temperature T1 in the secondary dust removal main duct is ≤110℃, close mixing valve one and mixing valve two.

[0021] 3) After the converter oxygen blowing is completed, open the furnace rear dust collector valve 1 and furnace rear dust collector valve 2 to their full positions, then close the furnace front dust collector valve 1 and furnace front dust collector valve 2. After the converter tapping is completed, open the furnace front dust collector valve 1 and furnace front dust collector valve 2 to their full positions, then close the furnace rear dust collector valve 1 and furnace rear dust collector valve 2.

[0022] The cooling water regulating valve used to control the spray gun increases the cooling water spray flow rate when the detected flue gas temperature rises.

[0023] If the flue gas temperature T4 at the dust collector inlet exceeds 100℃, a high temperature alarm will be triggered on the secondary dust collector.

[0024] If the flue gas temperature T4 at the dust collector inlet is greater than 120℃, the dust collector fan will be shut down.

[0025] When the converter production ends, the dust removal fan runs at low speed.

[0026] A method for cooling flue gas from a converter's secondary dust removal system includes the following steps for opening the aerosol spray gun: opening the compressed air shut-off valve, setting a time, and then opening the water shut-off valve; and closing the aerosol spray gun involves closing the water shut-off valve first, setting a time, and then closing the compressed air shut-off valve.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. One end of the main flue gas duct is connected to the input end of the secondary dust collector, and the other end of the main flue gas duct is connected to one end of flue gas branch duct one and one end of flue gas branch duct two respectively. Aerosol spray guns are installed on the main flue gas duct, flue gas branch duct one and flue gas branch duct two. According to the preset conditions, the accuracy of cooling the flue gas temperature of each section of the duct is improved. The structure is simple and easy to implement.

[0029] 2. A connecting flange is installed at the junction of the nozzle and the spray gun body, so that the equipment can be easily replaced when the spray gun leaks or malfunctions;

[0030] 3. The other end of flue gas branch pipe one is connected to one end of the dust collector hood through connecting pipe one, and the other end of flue gas branch pipe two is connected to the other end of the dust collector hood through connecting pipe two. Dust collector valve one before the furnace and dust collector valve one after the furnace are installed in sequence on connecting pipe one, and dust collector valve two before the furnace and dust collector valve two after the furnace are installed in sequence on connecting pipe two. The installation of dust collector valve one before the furnace and dust collector valve one after the furnace, dust collector valve two before the furnace and dust collector valve two after the furnace is used to draw in the flue gas generated around the converter and improve the dust removal effect.

[0031] 4. The dust collector inlet thermocouple and the flue gas main inlet thermocouple are installed sequentially at the input end of the flue gas main duct near the secondary dust collector. Flue gas branch pipe thermocouple one is installed on flue gas branch pipe one, and flue gas branch pipe thermocouple two is installed on flue gas branch pipe two. A water flow meter is installed on the cooling water pipe. Sensors are installed to detect the flue gas temperature of each section of the pipe to facilitate precise cooling of the flue gas. The water flow meter on the cooling water pipe enables closed-loop flow control to ensure the cooling effect.

[0032] 5. The main flue gas duct is equipped with mixing valve one and mixing valve two. When the flue gas temperature in the main duct is low, it is cooled by mixing in outside air, which reduces the energy consumption of water spray cooling.

[0033] 6. Collect the temperature of the secondary dust removal main duct and flue gas branch ducts, and adopt multi-stage cooling for different flue gas temperatures to achieve effective control of flue gas temperature, keep the flue gas temperature within a reasonable range, ensure that the secondary dust collector is in optimal condition, reduce the risk of dust collector bags or filter cartridges burning, achieve stable operation of the dust removal system, and ensure high-efficiency and low-cost operation of the dust removal system. Attached Figure Description

[0034] Figure 1 This is a structural diagram of the converter's secondary dust removal flue gas cooling system.

[0035] Figure 2 This is a schematic diagram of the aerosol spray gun structure.

[0036] In the diagram: 1-Flue gas branch pipe thermocouple 1; 2-1# aerosol spray gun; 3-Converter; 4-Dust collector hood; 5-2# aerosol spray gun; 6-Flue gas branch pipe thermocouple 2; 7-3# aerosol spray gun; 8-Flue gas main pipe inlet thermocouple; 9-4# aerosol spray gun; 10-Post-furnace dust collector valve 2; 11-5# aerosol spray gun; 12-6# aerosol spray gun; 13-Secondary dust collector; 14-Flue gas branch pipe 1; 15-Pre-furnace dust collector valve 1; 16-Post-furnace dust collector... 17 - Dust valve 1 - Furnace front dust removal valve 2 - Mixing air valve 1 - Mixing air valve 2 - Dust collector inlet thermocouple - Dust removal fan - Chimney - Manual water valve - Manual air valve - Compressed air shut-off valve - Compressed air pipeline - Nozzle - Connecting flange - Water shut-off valve - Cooling water regulating valve - Cooling water pipeline - Water flow meter - Flue gas branch pipeline 2 Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0038] The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0039]

Example 1

[0040] Six sets of air / water mixing atomizing spray guns are designed and installed in the secondary dust removal pipeline of converter 3. Three sets are installed on the branch pipes of the dust removal pipeline, two sets on the longer branch pipes and one set on the shorter branch pipes. Three sets are installed on the main flue gas pipe. One flue gas temperature measuring thermocouple is installed on each of the two flue gas branch pipes to detect the flue gas temperature T2 and T3 within the secondary dust removal branch pipes of converter 3. One thermocouple is installed on the main dust removal pipeline after the branch pipes merge to detect the flue gas temperature T1. A temperature measuring thermocouple T4 is installed at the dust collector inlet to detect the flue gas temperature at the dust collector inlet. Two mixing valves are installed in the secondary flue gas pipeline before the dust collector to mix in external air for cooling. Six water shut-off valves 29, regulating valves, and flow meters are installed in the water supply pipelines of the six sets of air / water mixing atomizing spray guns for controlling the cooling water. Six gas shut-off valves are installed for controlling the compressed air.

[0041] See Figure 1A secondary dust removal and flue gas cooling system for a converter 3 includes a dust removal fan 21, a secondary dust collector 13, and a dust collection hood 4. The dust collection hood 4 is installed above the furnace door of the converter 3. The output end of the dust removal fan 21 is connected to the chimney 22, and the input end of the dust removal fan 21 is connected to the output end of the secondary dust collector 13. The system also includes a main flue gas duct, a first flue gas branch duct 14, a second flue gas branch duct 33, a cooling water duct 31, and a compressed air duct 26. One end of the main flue gas duct is connected to the input end of the secondary dust collector 13, and the other end is connected to the flue gas... One end of branch pipe 14 and one end of flue gas branch pipe 2 33 are connected. The other end of flue gas branch pipe 14 is connected to one end of dust hood 4 through connecting pipe 1, and the other end of flue gas branch pipe 2 33 is connected to the other end of dust hood 4 through connecting pipe 2. Dust removal valve 15 and dust removal valve 16 are installed sequentially on connecting pipe 1, and dust removal valve 17 and dust removal valve 10 are installed sequentially on connecting pipe 2. Aerosol spray guns are installed on the main flue gas pipe, flue gas branch pipe 14, and flue gas branch pipe 2 33, and the number of aerosol spray guns is ≥1. See Figure 2 One end of the cooling water pipe 31 is connected to the water inlet pipe of the aerosol spray gun, one end of the compressed air pipe 26 is connected to the air inlet pipe of the aerosol spray gun, the other end of the cooling water pipe 31 is connected to a water source, and the other end of the compressed air pipe 26 is connected to an air source; the aerosol spray gun includes a nozzle 27 and a spray gun body, the nozzle 27 is provided with multiple water outlets, and a connecting flange 28 is provided at the junction of the nozzle 27 and the spray gun body, the connecting flange 28 is used to fix the aerosol spray gun to the flue gas pipe.

[0042] Near the input end of the secondary dust collector 13, near the main flue gas duct, a dust collector inlet thermocouple 20, a mixing valve 18, a mixing valve 29, and a main flue gas duct inlet thermocouple 8 are installed in sequence. The dust collector inlet thermocouple 20 is used to detect the flue gas temperature T4 at the dust collector inlet, and the main flue gas duct inlet thermocouple 8 is used to detect the flue gas temperature T1 in the secondary dust collector main duct. A flue gas branch pipe thermocouple 1 is installed on the first flue gas duct 14, and a flue gas branch pipe thermocouple 26 is installed on the second flue gas branch pipe 33. The flue gas branch pipe thermocouple 1 is used to detect the flue gas temperature T2 in the first flue gas branch pipe 14, and the flue gas branch pipe thermocouple 26 is used to detect the flue gas temperature T3 in the second flue gas branch pipe 33. A water flow meter 32, a cooling water regulating valve 30, and a water shut-off valve 29 are installed in sequence on the cooling water duct 31, and a compressed air shut-off valve 25 is installed on the compressed air duct 26.

[0043] The flue gas branch pipe thermocouple 1, flue gas branch pipe thermocouple 2, water flow meter 32, dust collector inlet thermocouple 20, and flue gas main duct inlet thermocouple 8 are connected to the input terminals of the PLC via ports. Cooling water regulating valve 30, water shut-off valve 29, compressed air shut-off valve 25, mixing valve 18, and mixing valve 29 are connected to the output terminals of the PLC via ports. The PLC includes digital output modules, analog input modules, and analog output modules. The flue gas branch pipe thermocouple 1, flue gas branch pipe thermocouple 2, water flow meter 32, dust collector inlet thermocouple 20, and flue gas main duct inlet thermocouple 8 are connected to the input terminals of the analog input modules. Water shut-off valve 29, compressed air shut-off valve 25, mixing valve 18, and mixing valve 29 are connected to the output terminals of the digital output modules. Cooling water regulating valve 30 is connected to the output terminal of the analog output modules. A PLC includes a CPU module, a digital output module, an analog input module, and an analog output module. The CPU module is connected via ports.

[0044] A method for cooling flue gas from a secondary dust removal system in a converter includes:

[0045] In a temperature rise and fall cycle, 1) during temperature rise:

[0046] When the flue gas temperature T1 in the secondary dust removal main duct is greater than 150℃, the mixing valve 18 and mixing valve 29 before the dust collector inlet are fully opened, and the air mixed in by the mixing valve 18 and mixing valve 29 cools the secondary flue gas.

[0047] When the flue gas temperature T1 in the secondary dust removal main duct is within the range of 250℃<T1≤350℃, the No. 5 aerosol spray gun 11 installed in the main flue gas duct is turned on to spray and cool the flue gas passing through the No. 5 aerosol spray gun 11. The spray volume of the No. 5 aerosol spray gun 11 is set to 3m³ / h. 3 / h.

[0048] When the flue gas temperature T1 in the secondary dust removal main duct is within the range of 350℃<T1≤450℃, the No. 6 aerosol spray gun 12 installed in the main flue gas duct is turned on to spray and cool the flue gas passing through the No. 6 aerosol spray gun 12. The water spray volume of the No. 6 aerosol spray gun 12 is set to 3m³ / h. 3 / h.

[0049] When the flue gas temperature T1 in the secondary dust removal main duct is within the range of 450℃<T1≤500℃, turn on the No. 4 aerosol spray gun 9 installed in the main flue gas duct to spray and cool the flue gas passing through the No. 4 aerosol spray gun 9. The water spray volume of No. 4, No. 5, No. 6 aerosol spray guns 9, spray gun 11, and spray gun 12 is set to 4m³ / h. 3 / h; Simultaneously, when the flue gas temperature T2 in flue gas branch duct 14 exceeds 450℃, open the No. 1 aerosol spray gun 2 and No. 3 aerosol spray gun 7 of flue gas branch duct 14 to spray and cool the flue gas passing through the No. 1 aerosol spray gun 2 and No. 3 aerosol spray gun 7 respectively. The spray volume of the No. 1 aerosol spray gun 2 and No. 3 aerosol spray gun 7 is set to 4m³ / h. 3 / h; When the flue gas temperature T3 in flue gas branch pipe 23 is >450℃, turn on the #2 aerosol spray gun 5 of flue gas branch pipe 2, and set the water flow rate to 4m³ / h. 3 / h.

[0050] When the flue gas temperature T1 in the secondary dust removal main duct is greater than 500℃, the water spray volume of spray guns #1 (2), #2 (5), #3 (7), #4 (9), #5 (11), and #6 (12) is set to 5m³ / h. 3 / h.

[0051] 2) During cooling;

[0052] When the flue gas temperature T1 in the secondary dust removal main duct is ≤300℃, shut down No. 1 aerosol spray gun 2, No. 2 aerosol spray gun 5, No. 3 aerosol spray gun 7, and No. 4 aerosol spray gun 9.

[0053] When the flue gas temperature T1 in the secondary dust removal main duct is ≤170℃, the No. 6 aerosol spray gun 12 installed in the flue gas main duct will be shut off.

[0054] When the flue gas temperature T1 in the secondary dust removal main duct is ≤160℃, then shut off the No. 5 aerosol spray gun 11 installed in the flue gas main duct.

[0055] If the flue gas temperature T1 in the secondary dust removal main duct is ≤110℃, close the mixing valve 18 and the mixing valve 29.

[0056] 3) After the converter oxygen blowing is completed, open the furnace rear dust collector valve 1 and furnace rear dust collector valve 2 to their positions, then close the furnace front dust collector valve 1 and furnace front dust collector valve 2. After the converter tapping is completed, open the furnace front dust collector valve 1 and furnace front dust collector valve 2 to their positions, then close the furnace rear dust collector valve 1 and furnace rear dust collector valve 2.

[0057] All cooling water regulating valves used to control the spray guns automatically adjust according to set conditions when the detected flue gas temperature rises, increasing the cooling water spray flow rate, and forming a closed-loop control with the pipeline water flow rate detected after the regulating valve.

[0058] If the flue gas temperature at the dust collector inlet T4 is greater than 100℃, the secondary dust collector will trigger a high-temperature alarm (13).

[0059] When the flue gas temperature T4 at the dust collector inlet is greater than 120℃, the dust collector fan 21 is quickly shut down (shutting down means that the high-voltage system is tripped and the fan motor stops running);

[0060] When converter 3 finishes production, dust removal fan 21 runs at low speed.

[0061] Open the compressed air shut-off valve 25, set a time of 5 seconds, and then open the water shut-off valve 29; the process of closing the aerosol spray gun is as follows: first close the water shut-off valve 29, set a time of 5 seconds, and then close the compressed air shut-off valve 25.

[0062] One end of the main flue gas duct of this invention is connected to the input end of the secondary dust collector, and the other end of the main flue gas duct is connected to one end of flue gas branch duct one and one end of flue gas branch duct two, respectively. Each of the main flue gas duct, flue gas branch duct one, and flue gas branch duct two is equipped with an aerosol spray gun. Based on preset conditions, this improves the accuracy of cooling the flue gas temperature in each section of the duct. The structure is simple and easy to implement. A connecting flange is provided at the junction of the nozzle and the spray gun cylinder, facilitating equipment replacement in case of leakage or malfunction. The other end of flue gas branch duct one is connected to one end of the dust collector hood via a connecting pipe one, and the other end of flue gas branch duct two is connected to the other end of the dust collector hood via a connecting pipe two. A furnace-front dust collector valve one and a furnace-rear dust collector valve one are sequentially installed on the connecting pipe one, and a furnace-front dust collector valve two and a furnace-rear dust collector valve two are sequentially installed on the connecting pipe two. These three dust collector valves are used to draw in the flue gas generated around the converter, improving the dust removal effect. A thermocouple is installed sequentially near the input end of the secondary dust collector, along with the inlet thermocouple of the main flue gas duct. A branch pipe thermocouple is installed on branch pipe one, and another on branch pipe two. A flow meter is installed on the cooling water pipe, and sensors are used to detect the flue gas temperature in each section of the pipe, facilitating precise cooling of the flue gas. The flow meter also enables closed-loop flow control to ensure effective cooling. Two mixing valves are installed in the main flue gas duct. When the flue gas temperature in the main duct is low, ambient air is mixed in for cooling, reducing the energy consumption of water spray cooling. Temperature data is collected from the main secondary dust collector duct and the branch flue gas ducts. Multi-stage cooling is employed for different flue gas temperatures to effectively control the flue gas temperature, keeping it within a reasonable range. This ensures the secondary dust collector is in optimal condition, reduces the risk of burn-out of filter bags or cartridges, and achieves stable, high-efficiency, and low-cost operation of the dust collection system.

Claims

1. A method for cooling flue gas from a converter under secondary dust removal, implemented using a converter secondary dust removal flue gas cooling system, the cooling system comprising a dust removal fan, a secondary dust collector, and a dust collection hood, the dust collection hood being installed above the converter's main entrance, the output end of the dust removal fan being connected to the chimney, and the input end of the dust removal fan being connected to the output end of the secondary dust collector, characterized in that... It also includes a main flue gas duct, flue gas branch duct 1, flue gas branch duct 2, cooling water duct, and compressed air duct. One end of the main flue gas duct is connected to the input end of the secondary dust collector, and the other end of the main flue gas duct is connected to one end of flue gas branch duct 1 and one end of flue gas branch duct 2, respectively. The other end of flue gas branch duct 1 is connected to one end of the dust collector hood through a connecting pipe 1, and the other end of flue gas branch duct 2 is connected to the other end of the dust collector hood through a connecting pipe 2. Each of the main flue gas duct, flue gas branch duct 1, and flue gas branch duct 2 is equipped with an aerosol spray gun. The number of aerosol spray guns is ≥1 set, and each set contains several aerosol spray guns. One end of the cooling water pipe is connected to the water inlet pipe of the aerosol spray gun, one end of the compressed air pipe is connected to the air inlet pipe of the aerosol spray gun, the other end of the cooling water pipe is connected to the water source, and the other end of the compressed air pipe is connected to the air source. The system described above is used to implement a method for cooling flue gas from a converter's secondary dust removal process, comprising: In a temperature rise and fall cycle, 1) during temperature rise: When the flue gas temperature in the secondary dust removal main duct is T1 > 150℃, both mixing valve one and mixing valve two are fully opened, and the air mixed in by mixing valve one and mixing valve two cools the secondary flue gas. When the flue gas temperature T1 in the secondary dust removal main duct is greater than 250℃, the aerosol spray guns installed in the main flue gas duct are turned on sequentially. The water flow rate of the aerosol spray guns in the main flue gas duct is 3~5m³. 3 Between / h, and if the flue gas temperature T2 in flue gas branch duct 1 is >450℃, turn on the aerosol spray gun in flue gas branch duct 1, and set the water flow rate to 4~5m³ / h. 3 / h; When the flue gas temperature T3 in flue gas branch duct 2 is >450℃, turn on the aerosol spray gun in flue gas branch duct 2, and set the water flow rate to 4~5m 3 Between / h; 2) During cooling; When the flue gas temperature T1 in the secondary dust removal main duct is ≤300℃, close the aerosol spray guns in flue gas branch duct 1, flue gas branch duct 2, and one-third of the aerosol spray guns installed in the flue gas main duct. When the flue gas temperature T1 in the secondary dust removal main duct is ≤170℃, close one-third of the aerosol spray guns installed in the flue gas main duct. The one-third number of aerosol spray guns is rounded up. When the flue gas temperature T1 in the secondary dust removal main duct is ≤160℃, shut down the remaining aerosol spray guns installed in the flue gas main duct. If the flue gas temperature T1 in the secondary dust removal main duct is ≤110℃, close mixing valve one and mixing valve two. 3) After the converter oxygen blowing is completed, open the furnace rear dust removal valve 1 and furnace rear dust removal valve 2 to their positions, and then close the furnace front dust removal valve 1 and furnace front dust removal valve 2. After the converter tapping is completed, open the furnace front dust removal valve 1 and furnace front dust removal valve 2 to their positions, and then close the furnace rear dust removal valve 1 and furnace rear dust removal valve 2. The cooling water regulating valve used to control the spray gun increases the cooling water spray flow rate when the detected flue gas temperature rises. If the flue gas temperature T4 at the dust collector inlet exceeds 100℃, a high temperature alarm will be triggered on the secondary dust collector. If the flue gas temperature T4 at the dust collector inlet is greater than 120℃, the dust collector fan will be shut down. When converter production ends, the dust removal fan runs at low speed; A furnace front dust removal valve 1 and a furnace rear dust removal valve 1 are sequentially installed on the first connecting pipe, and a furnace front dust removal valve 2 and a furnace rear dust removal valve 2 are sequentially installed on the second connecting pipe. The flue gas main duct is equipped with a dust collector inlet thermocouple, mixing valve one, mixing valve two, and flue gas main duct inlet thermocouple in sequence near the input end of the secondary dust collector. The dust collector inlet thermocouple is used to detect the flue gas temperature T4 at the dust collector inlet, and the flue gas main duct inlet thermocouple is used to detect the flue gas temperature T1 in the secondary dust collector main duct.

2. The method for cooling flue gas from a converter secondary dust removal system according to claim 1, characterized in that, The aerosol spray gun includes a nozzle and a spray gun body. The nozzle is provided with multiple water outlets, and a connecting flange is provided at the junction of the nozzle and the spray gun body. The connecting flange is used to fix the aerosol spray gun to the flue gas duct.

3. The method for cooling flue gas from a converter secondary dust removal system according to claim 1, characterized in that, Flue gas branch pipe thermocouple one is installed on flue gas branch pipe one, and flue gas branch pipe thermocouple two is installed on flue gas branch pipe two. Flue gas branch pipe thermocouple one is used to detect the flue gas temperature T2 in flue gas branch pipe one, and flue gas branch pipe thermocouple two is used to detect the flue gas temperature T3 in flue gas branch pipe two. A water flow meter, a cooling water regulating valve, and a water shut-off valve are installed in sequence on the cooling water pipe, and a compressed air shut-off valve is installed on the compressed air pipe. The flue gas branch thermocouple 1, flue gas branch thermocouple 2, water flow meter, cooling water regulating valve, water shut-off valve, compressed air shut-off valve, dust collector inlet thermocouple, mixing valve 1, mixing valve 2, and flue gas main pipe inlet thermocouple are respectively connected to the control unit.

4. The method for cooling flue gas from a converter secondary dust removal system according to claim 3, characterized in that, The control unit is a PLC. The flue gas branch thermocouple 1, flue gas branch thermocouple 2, water flow meter, dust collector inlet thermocouple, and flue gas main pipe inlet thermocouple are respectively connected to the input terminal of the PLC through ports. The cooling water regulating valve, water shut-off valve, compressed air shut-off valve, mixing valve 1, and mixing valve 2 are connected to the output terminal of the PLC through ports.

5. The method for cooling flue gas from a converter secondary dust removal system according to claim 3, characterized in that, The process of turning on the aerosol spray gun is as follows: open the compressed air shut-off valve, set the time, and then open the water shut-off valve; the process of turning off the aerosol spray gun is as follows: first close the water shut-off valve, set the time, and then close the compressed air shut-off valve.

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