Converter secondary dedusting flue gas cooling system and method

Abstract

The invention relates to a converter secondary dust removal flue gas cooling system and method.One end of a flue gas main is connected with the input end of a secondary dust remover, the other end of the flue gas main is communicated with one end of a first flue gas branch pipeline and one end of a second flue gas branch pipeline, and the other end of the first flue gas branch pipeline is connected with one end of a dust removal cover through a first communicating pipe; the other end of the flue gas branch pipeline II is connected with the other end of the dust removal cover through a communicating pipe II; the smoke main pipeline, the first smoke branch pipeline and the second smoke branch pipeline are each provided with an aerial fog spray gun, and the number of the aerial fog spray guns is larger than or equal to 1. The system has the advantages that the temperatures of the secondary dust removal main pipeline and the flue gas branch pipelines are collected, multi-section cooling is adopted for different flue gas temperatures, flue gas temperature control is achieved, the flue gas temperature is kept within a reasonable range all the time, the burning risk of a dust removal cloth bag or a filter cartridge is reduced, stable operation of the dust removal system is achieved, and the service life of the dust removal system is prolonged. High-efficiency and low-cost operation of the dust removal system is ensured.

Description

Technical Field

[0001] The invention relates to the technical 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 Art

[0002] During the production of top-bottom composite injection converters in domestic steel enterprises, a large amount of high-temperature, high-dust gas will be generated. In the dust removal systems in various areas of the converter, the dust removal system responsible for collecting the flue gas generated during the converter iron addition, scrap steel addition, converter steel tapping, and slag pouring processes is called "secondary dust removal". The secondary dust removal system also has the function of collecting the flue gas overflowed from the primary dust removal. The secondary dust removal uses a closed smoke box to collect the flue gas generated at each stage of converter production, and is an important environmental protection equipment in converter production. However, in actual applications, during the converter iron addition process, a large amount of high-temperature combustible gas is generated and burned at the furnace mouth or a large splash occurs during the converter smelting process, which will cause the flue gas temperature to rise rapidly. 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 bags or filter cartridges in the secondary dust collector are heated and burned, resulting in a decrease in dust collector performance and substandard particulate matter discharged. Summary of the invention

[0003] The purpose of the present invention is to provide a converter secondary dust removal flue gas cooling system and method to solve the problem that in the converter production process, when the converter is adding iron and smelting, a large amount of high-temperature combustible gas is burned or a large splash occurs in the converter smelting process, causing the temperature of the secondary dust removal system to rise rapidly, the flue gas temperature fluctuates greatly and cannot be controlled, the bags or filter cartridges in the dust collector are burned, the dust removal performance of the dust collector is reduced, and production is stopped, thereby ensuring the dust removal system to operate with high efficiency and low cost.

[0004] To achieve the above object, the present invention is implemented through the following technical solutions:

[0005] A converter secondary dust removal flue gas cooling system comprises a dust removal fan, a secondary dust collector, and a dust removal hood. The dust removal hood is arranged above the front door of the converter furnace. 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 comprises a flue gas main duct, a flue gas branch duct 1, a flue gas branch duct 2, a cooling water duct, and a compressed air duct. One end of the flue gas main duct is connected to the input end of the secondary dust collector, and the other end of the flue gas main duct is respectively connected to one end of the flue gas branch duct 1 and one end of the flue gas branch duct 2. The other end of the flue gas branch duct 1 is connected to one end of the dust removal hood through a connecting pipe 1, and the other end of the flue gas branch duct 2 is connected to the other end of the dust removal hood through a connecting pipe 2.

[0006] Aerosol spray guns are installed on the main flue gas duct, the first flue gas branch duct and the second flue gas branch duct. The number of aerosol spray guns is ≥ 1 group, and the number of aerosol spray guns in each group is a number. 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.

[0007] The aerosol spray gun comprises a nozzle and a spray gun barrel. The nozzle is provided with a plurality of water outlets. A connecting flange is provided at the joint of the nozzle and the spray gun barrel. The connecting flange is used to fix the aerosol spray gun to the smoke pipe.

[0008] A furnace front dust removal valve 1 and a furnace rear dust removal valve 1 are arranged in sequence on the connecting pipe 1, and a furnace front dust removal valve 2 and a furnace rear dust removal valve 2 are arranged in sequence on the connecting pipe 2.

[0009] The dust collector inlet thermocouple, air mixing valve 1, air mixing valve 2, and flue gas main duct inlet thermocouple are sequentially arranged 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 dust collector inlet flue gas temperature T4, the flue gas main duct inlet thermocouple is used to detect the secondary dust collection main duct flue gas temperature T1, the flue gas branch pipe thermocouple 1 is arranged on the flue gas branch pipe 1, the flue gas branch pipe thermocouple 2 is arranged on the flue gas branch pipe 2, the flue gas branch pipe thermocouple 1 is used to detect the flue gas temperature T2 in the flue gas branch pipe 1, the flue gas branch pipe thermocouple 2 is used to detect the flue gas temperature T3 in the flue gas branch pipe 2, the cooling water pipe is sequentially provided with a water flow meter, a cooling water regulating valve, and a water shut-off valve, and the compressed air pipe is provided with a compressed air shut-off valve;

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

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

[0012] A converter secondary dust removal flue gas cooling method, comprising:

[0013] In a temperature rise and fall cycle, 1) when the temperature rises:

[0014] When the flue gas temperature in the secondary dust removal main duct is T1>150℃, the air mixing valve 1 and the air mixing valve 2 are fully opened, and the air volume mixed by the air mixing valve 1 and the air mixing valve 2 cools the secondary flue gas;

[0015] When the flue gas temperature T1 in the secondary dust removal main duct is T1>250℃, the aerosol spray guns installed in the flue gas main duct are opened successively. The water volume of the aerosol spray guns in the flue gas main duct ranges from 3 to 5m 3 / h. At the same time, if the smoke temperature T2 in the smoke branch pipe 1 is greater than 450℃, open the aerosol spray gun of the smoke branch pipe 1 and set the water volume at 4-5m 3 / h; When T3>450℃, open the aerosol spray gun of the second flue gas branch pipe, and set the water volume at 4~5m 3 / h;

[0016] 2) When the temperature drops;

[0017] When the flue gas temperature T1 of the secondary dust removal main duct is ≤300℃, close the aerosol spray guns of the flue gas branch duct 1, the aerosol spray guns of the flue gas branch duct 2, and one-third of the aerosol spray guns installed in the flue gas main duct;

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

[0019] When the flue gas temperature T1 of the secondary dust removal main duct is ≤160℃, turn off the remaining aerosol spray guns installed in the flue gas main duct;

[0020] The flue gas temperature in the secondary dust removal main pipeline is T1≤110℃, and the air mixing valve 1 and air mixing valve 2 are closed;

[0021] 3) After the converter oxygen blowing is completed, open the dust removal valve 1 and the dust removal valve 2 at the rear of the furnace, and then close the dust removal valve 1 and the dust removal valve 2 at the front of the furnace. After the converter steel is tapped, open the dust removal valve 1 and the dust removal valve 2 at the front of the furnace, and then close the dust removal valve 1 and the dust removal valve 2 at the rear of the furnace;

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

[0023] The dust collector inlet flue gas temperature T4>100℃, the secondary dust collector high temperature alarm;

[0024] When the dust collector inlet flue gas temperature T4 is greater than 120°C, the dust removal fan is shut down;

[0025] At the end of converter production, the dust removal fan runs at low speed.

[0026] A converter secondary dust removal fume cooling method, the process of opening the aerosol spray gun is: opening the compressed air cut-off valve, and then opening the water cut-off valve after setting the time; the process of closing the aerosol spray gun is: first closing the water cut-off valve, and then closing the compressed air cut-off valve after setting the time.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[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 the flue gas branch duct 1 and one end of the flue gas branch duct 2 respectively. The main flue gas duct, the flue gas branch duct 1 and the flue gas branch duct 2 are all provided with aerosol spray guns. 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 set at the joint between the nozzle and the spray gun barrel, which makes it easy to replace the equipment when the spray gun leaks or fails;

[0030] 3. The other end of the flue gas branch pipe 1 is connected to one end of the dust removal hood through the connecting pipe 1, and the other end of the flue gas branch pipe 2 is connected to the other end of the dust removal hood through the connecting pipe 2. The connecting pipe 1 is provided with a furnace front dust removal valve 1 and a furnace rear dust removal valve 1 in sequence, and the connecting pipe 2 is provided with a furnace front dust removal valve 2 and a furnace rear dust removal valve 2 in sequence. The furnace front dust removal valve 1, the furnace rear dust removal valve 1, the furnace front dust removal valve 2 and the furnace rear dust removal valve 2 are provided to inhale the flue gas generated around the converter to improve the dust removal effect;

[0031] 4. The inlet thermocouple of the dust collector and the inlet thermocouple of the flue gas main duct are arranged in sequence at the input end of the flue gas main duct near the secondary dust collector. The first flue gas branch pipe thermocouple is arranged on the first flue gas branch pipe, and the second flue gas branch pipe thermocouple is arranged on the second flue gas branch pipe. A water flow meter is arranged on the cooling water pipe. Sensors are arranged to detect the flue gas temperature of each section of the pipe to facilitate accurate cooling of the flue gas. A water flow meter is arranged on the cooling water pipe to realize closed-loop flow control and ensure the cooling effect.

[0032] 5. The main flue gas duct is equipped with air mixing valves 1 and 2. When the flue gas temperature in the main duct is low, it can be cooled by mixing with outside air to reduce the energy consumption of water spray cooling;

[0033] 6. Collect the temperature of the secondary dust removal main duct and the flue gas branch duct, and use multi-stage cooling for different flue gas temperatures to achieve effective control of the flue gas temperature, so that the flue gas temperature is always maintained in a reasonable range, ensuring that the secondary dust collector is in the best condition, reducing the risk of burning of dust bags or filter cartridges, achieving stable operation of the dust removal system, and ensuring high-efficiency and low-cost operation of the dust removal system. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0036] In the figure: 1-smoke branch pipe thermocouple 1 2-1# aerosol spray gun 3-converter 4-dust removal hood 5-2# aerosol spray gun 6-smoke branch pipe thermocouple 2 7-3# aerosol spray gun 8-smoke main pipe inlet thermocouple 9-4# aerosol spray gun 10-rear dust removal valve 2 11-5# aerosol spray gun 12-6# aerosol spray gun 13-secondary dust collector 14-smoke branch pipe 1 15-front dust removal valve 1 16-rear dust removal Dust valve one 17-furnace front dust removal valve two 18-air mixing valve one 19-air mixing valve two 20-dust collector inlet thermocouple 21-dust removal fan 22-chimney 23-manual water valve 24-manual air valve 25-compressed air cut-off valve 26-compressed air pipeline 27-nozzle 28-connecting flange 29-water cut-off valve 30-cooling water regulating valve 31-cooling water pipeline 32-water flow meter 33-flue gas branch pipeline two. DETAILED DESCRIPTION

[0037] The present invention is described in detail below in conjunction with 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 examples are implemented on the premise of the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples. The methods used in the following examples are conventional methods unless otherwise specified.

[0039] [Example 1]

[0040] Six sets of air / water mixed atomizing spray guns are designed and installed in the secondary dust removal pipeline of converter 3, of which three sets are installed in the branch pipes of the dust removal pipeline, two sets of atomizing spray guns are installed in the longer branch pipes, one set of atomizing spray guns is installed in the shorter branch pipe, and three sets of atomizing spray guns are installed in the flue gas main pipe; one set of flue gas temperature measuring thermocouples are installed in each of the two flue gas branches for detecting the flue gas temperatures T2 and T3 in the secondary dust removal branch pipes of converter 3, one set of thermocouples is installed in the dust removal main pipe after the branch pipes are merged, for detecting the flue gas temperature T1 in the secondary dust removal main pipe of converter 3, and a temperature measuring thermocouple T4 is installed at the inlet of the dust collector to detect the flue gas temperature at the inlet of the dust collector; two mixing air valves are installed in the secondary flue gas pipeline before the dust collector for mixing 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 mixed atomizing spray guns for controlling cooling water; six gas shut-off valves are installed for controlling compressed air.

[0041] See Figure 1A secondary dust removal flue gas cooling system for a converter 3 includes a dust removal fan 21, a secondary dust collector 13, and a dust removal hood 4. The dust removal hood 4 is arranged above the furnace front 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. It also includes a flue gas main pipeline, a flue gas branch pipeline 14, a flue gas branch pipeline 23, a cooling water pipeline 31, and a compressed air pipeline 26. One end of the flue gas main pipeline is connected to the input end of the secondary dust collector 13, and the other end of the flue gas main pipeline is connected to the flue gas main pipeline. One end of the branch pipe 14 is connected to one end of the flue gas branch pipe 2 33, the other end of the flue gas branch pipe 14 is connected to one end of the dust hood 4 through a connecting pipe 1, and the other end of the flue gas branch pipe 2 33 is connected to the other end of the dust hood 4 through a connecting pipe 2; a furnace front dust removal valve 15 and a furnace rear dust removal valve 16 are arranged on the connecting pipe 1 in sequence, and a furnace front dust removal valve 2 17 and a furnace rear dust removal valve 2 10 are arranged on the connecting pipe 2 in sequence; aerosol spray guns are arranged on the flue gas main pipe, the flue gas branch pipe 14 and the 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 barrel, a plurality of water outlets are arranged on the nozzle 27, and a connecting flange 28 is arranged at the junction of the nozzle 27 and the spray gun barrel, and the connecting flange 28 is used to fix the aerosol spray gun to the flue gas pipe.

[0042] A dust collector inlet thermocouple 20, an air mixing valve 18, an air mixing valve 2 19, and a smoke main duct inlet thermocouple 8 are sequentially arranged at the input end of the smoke main duct near the secondary dust collector 13. The dust collector inlet thermocouple 20 is used to detect the dust collector inlet flue gas temperature T4, and the smoke main duct inlet thermocouple 8 is used to detect the secondary dust collection main duct flue gas temperature T1. A smoke branch pipe thermocouple 1 is arranged on the smoke branch pipe 14, and a smoke branch pipe thermocouple 2 6 is arranged on the smoke branch pipe 2 33. The smoke branch pipe thermocouple 1 is used to detect the flue gas temperature T2 in the smoke branch pipe 14, and the smoke branch pipe thermocouple 2 6 is used to detect the flue gas temperature T3 in the smoke branch pipe 2 33. A water flow meter 32, a cooling water regulating valve 30, and a water cut-off valve 29 are sequentially arranged on the cooling water pipe 31, and a compressed air cut-off valve 25 is arranged on the compressed air pipe 26.

[0043] The flue gas branch thermocouple 1, the flue gas branch thermocouple 2, the water flow meter 32, the dust collector inlet thermocouple 20, and the flue gas main pipe inlet thermocouple 8 are connected to the input end of the PLC through ports, respectively. The cooling water regulating valve 30, the water cut-off valve 29, the compressed air cut-off valve 25, the air mixing valve 18, and the air mixing valve 2 19 are connected to the output end of the PLC through ports. The PLC includes a digital output module, an analog input module, and an analog output module. The flue gas branch thermocouple 1, the flue gas branch thermocouple 2, the water flow meter 32, the dust collector inlet thermocouple 20, and the flue gas main pipe inlet thermocouple 8 are connected to the input end of the analog input module, respectively. The water cut-off valve 29, the compressed air cut-off valve 25, the air mixing valve 18, and the air mixing valve 2 19 are connected to the output end of the digital output module, and the cooling water regulating valve 30 is connected to the output end of the analog output module. PLC includes CPU module, digital output module, analog input module, analog output module, and CPU module connected through ports.

[0044] A converter 3 secondary dust removal flue gas cooling method, comprising:

[0045] In a temperature rise and fall cycle, 1) when the temperature rises:

[0046] When the flue gas temperature T1 of the secondary dust removal main pipeline is greater than 150°C, the air mixing valve 18 and the air mixing valve 2 19 before the dust collector inlet are all opened, and the air volume mixed by the air mixing valve 18 and the air mixing valve 2 19 cools down the secondary flue gas.

[0047] When the flue gas temperature T1 of the secondary dust removal main pipeline is in the range of 250℃<T1≤350℃, the 5# aerosol spray gun 11 installed in the flue gas main pipeline is turned on to spray and cool the flue gas passing through the 5# aerosol spray gun 11. The water spray volume of the 5# aerosol spray gun 11 is set at 3m 3 / h.

[0048] When the flue gas temperature T1 of the secondary dust removal main pipeline is in the range of 350℃<T1≤450℃, the 6# aerosol spray gun 12 installed in the flue gas main pipeline is turned on to spray and cool the flue gas passing through the 6# aerosol spray gun 12. The water spray volume of the 6# aerosol spray gun 12 is set at 3m 3 / h.

[0049] When the flue gas temperature T1 in the secondary dust removal main pipeline is within the range of 450℃<T1≤500℃, open the 4# aerosol spray gun 9 installed in the flue gas main pipeline to spray and cool the flue gas passing through the 4# aerosol spray gun 9. The water spray volume of the 4#, 5#, 6# aerosol spray guns 9, spray guns 11 and spray guns 12 is set at 4m 3 / h; at the same time, when the smoke temperature T2 in the smoke branch pipe 14 is greater than 450°C, the 1# aerosol spray gun 2 and the 3# aerosol spray gun 7 of the smoke branch pipe 14 are turned on to spray and cool the smoke passing through the 1# aerosol spray gun 2 and the 3# aerosol spray gun 7, respectively. The water spraying volume of the 1# aerosol spray gun 2 and the 3# aerosol spray gun 7 is set at 4m 3 / h; When the flue gas temperature T3 in the flue gas branch pipe 2 33 is greater than 450°C, the 2# aerosol spray gun 5 of the aerosol spray gun of the flue gas branch pipe 2 is turned on, and the water volume is set to 4m 3 / h.

[0050] When the flue gas temperature T1 of the secondary dust removal main pipeline is greater than 500°C, the water spraying volume of 1# aerosol spray gun 2, 2# aerosol spray gun 5, 3# aerosol spray gun 7, 4# aerosol spray gun 9, 5# aerosol spray gun 11, and 6# aerosol spray gun 12 is set at 5m 3 / h.

[0051] 2) When the temperature drops;

[0052] When the flue gas temperature T1 of the secondary dust removal main pipeline is ≤300°C, close 1# aerosol spray gun 2, 2# aerosol spray gun 5, 3# aerosol spray gun 7, and 4# aerosol spray gun 9.

[0053] When the flue gas temperature T1 of the secondary dust removal main duct is ≤170°C, the 6# aerosol spray gun 12 installed in the flue gas main duct is closed.

[0054] When the flue gas temperature T1 of the secondary dust removal main duct is ≤160°C, the 5# aerosol spray gun 11 installed in the flue gas main duct is closed.

[0055] The flue gas temperature T1 of the secondary dust removal main pipeline is ≤110℃, and the air mixing valve 18 and the air mixing valve 2 19 are closed.

[0056] 3) After the converter oxygen blowing is completed, open the dust removal valve 1 and the dust removal valve 2 at the rear of the furnace, and then close the dust removal valve 1 and the dust removal valve 2 at the front of the furnace. After the converter steel is tapped, open the dust removal valve 1 and the dust removal valve 2 at the front of the furnace, and then close the dust removal valve 1 and the dust removal valve 2 at the rear of the furnace.

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

[0058] The dust collector inlet flue gas temperature T4>100℃, the secondary dust collector 13 high temperature alarm;

[0059] When the dust collector inlet flue gas temperature T4 is greater than 120°C, the dust removal fan 21 is quickly shut down (shutdown means the high-voltage system is disconnected and the fan motor stops running);

[0060] When the converter 3 is finished in production, the dust removal fan 21 runs at a low speed.

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

[0062] One end of the smoke main duct of the present invention is connected with the input end of the secondary dust collector, and the other end of the smoke main duct is connected with one end of the smoke branch duct one and one end of the smoke branch duct two respectively. The smoke main duct, the smoke branch duct one and the smoke branch duct two are all provided with aerosol spray guns. According to the preset conditions, the accuracy of cooling the smoke temperature of each section of the duct is improved, and the structure is simple and easy to implement. A connecting flange is provided at the junction of the nozzle and the spray gun barrel. When the spray gun leaks or fails, the equipment is convenient to replace. The other end of the smoke branch duct one is connected to one end of the dust hood through a connecting pipe one, and the other end of the smoke branch duct two is connected to the other end of the dust hood through a connecting pipe two. A front-furnace dust removal valve one and a rear-furnace dust removal valve one are arranged on the connecting pipe one in sequence, and a front-furnace dust removal valve two and a rear-furnace dust removal valve two are arranged on the connecting pipe two in sequence. The front-furnace dust removal valve one, the rear-furnace dust removal valve one, the front-furnace dust removal valve two and the rear-furnace dust removal valve two are arranged to inhale the smoke generated around the converter to improve the dust removal effect. The smoke main duct A thermocouple at the inlet of the dust collector and a thermocouple at the inlet of the main flue gas duct are arranged in sequence near the input end of the secondary dust collector, a flue gas branch pipe thermocouple 1 is arranged on the first flue gas branch pipe, a flue gas branch pipe thermocouple 2 is arranged on the second flue gas branch pipe, a water flow meter is arranged on the cooling water pipe, and a sensor is arranged to detect the flue gas temperature of each section of the pipe to facilitate accurate cooling of the flue gas. A water flow meter is arranged on the cooling water pipe to realize closed-loop flow control to ensure the cooling effect; a mixing valve 1 and a mixing valve 2 are arranged on the main flue gas duct. When the flue gas temperature in the main duct is low, it is cooled by mixing with outside air, thereby reducing the energy consumption of water spraying for cooling; the temperature of the secondary dust removal main duct and the flue gas branch duct is collected, and multi-stage cooling is adopted for different flue gas temperatures to realize effective control of the flue gas temperature, so that the flue gas temperature is always maintained in a reasonable range, ensuring that the secondary dust collector is in the best state, reducing the risk of burning of dust bags or filter cartridges, realizing stable operation of the dust removal system, and ensuring high-efficiency and low-cost operation of the dust removal system.

Claims

1. A converter secondary dust removal flue gas cooling system, comprising a dust removal fan, a secondary dust collector, and a dust removal hood, wherein the dust removal hood is arranged above the front door of the converter, 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. It is characterized in that It also includes a main flue gas pipeline, a first flue gas branch pipeline, a second flue gas branch pipeline, a cooling water pipeline, and a compressed air pipeline. One end of the main flue gas pipeline is connected to the input end of the secondary dust collector, and the other end of the main flue gas pipeline is respectively connected to one end of the first flue gas branch pipeline and one end of the second flue gas branch pipeline. The other end of the first flue gas branch pipeline is connected to one end of the dust hood through a connecting pipe 1, and the other end of the second flue gas branch pipeline is connected to the other end of the dust hood through a connecting pipe 2. Aerosol spray guns are installed on the main flue gas duct, the first flue gas branch duct and the second flue gas branch duct. The number of aerosol spray guns is ≥ 1 group, and the number of aerosol spray guns in each group is a number. 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.

2. A converter secondary dust removal flue gas cooling system according to claim 1, It is characterized in that The aerosol spray gun comprises a spray head and a spray gun barrel. The spray head is provided with a plurality of water outlets. A connecting flange is provided at the junction of the spray head and the spray gun barrel. The connecting flange is used to fixedly connect the aerosol spray gun to the smoke pipe.

3. A converter secondary dust removal flue gas cooling system according to claim 1, It is characterized in that The connecting pipe 1 is provided with a first dust removal valve in front of the furnace and a first dust removal valve in back of the furnace in sequence, and the connecting pipe 2 is provided with a second dust removal valve in front of the furnace and a second dust removal valve in back of the furnace in sequence.

4. A converter secondary dust removal flue gas cooling system according to claim 1, It is characterized in that The dust collector inlet thermocouple, air mixing valve 1, air mixing valve 2, and flue gas main duct inlet thermocouple are sequentially arranged 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 dust collector inlet flue gas temperature T4, the flue gas main duct inlet thermocouple is used to detect the secondary dust collection main duct flue gas temperature T1, the flue gas branch pipe thermocouple 1 is arranged on the flue gas branch pipe 1, the flue gas branch pipe thermocouple 2 is arranged on the flue gas branch pipe 2, the flue gas branch pipe thermocouple 1 is used to detect the flue gas temperature T2 in the flue gas branch pipe 1, the flue gas branch pipe thermocouple 2 is used to detect the flue gas temperature T3 in the flue gas branch pipe 2, the cooling water pipe is sequentially provided with a water flow meter, a cooling water regulating valve, and a water shut-off valve, and the compressed air pipe is provided with a compressed air shut-off valve; The flue gas branch pipe thermocouple 1, the flue gas branch pipe thermocouple 2, the water flow meter, the cooling water regulating valve, the water cut-off valve, the compressed air cut-off valve, the dust collector inlet thermocouple, the air mixing valve 1, the air mixing valve 2, and the flue gas main pipe inlet thermocouple are respectively connected to the control unit.

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

6. A method for cooling converter secondary dust removal flue gas according to any one of claims 1 to 5, It is characterized in that include: In a temperature rise and fall cycle, 1) when the temperature rises: When the flue gas temperature in the secondary dust removal main duct is T1>150℃, the air mixing valve 1 and the air mixing valve 2 are fully opened, and the air volume mixed by the air mixing valve 1 and the air mixing valve 2 cools the secondary flue gas; When the flue gas temperature T1 in the secondary dust removal main duct is T1>250℃, the aerosol spray guns installed in the flue gas main duct are opened successively. The water volume of the aerosol spray guns in the flue gas main duct ranges from 3 to 5m 3 / h. At the same time, if the smoke temperature T2 in the smoke branch pipe 1 is greater than 450℃, open the aerosol spray gun of the smoke branch pipe 1 and set the water volume at 4-5m 3 / h; When T3>450℃, open the aerosol spray gun of the second flue gas branch pipe, and set the water volume at 4~5m 3 / h; 2) When the temperature drops; When the flue gas temperature T1 of the secondary dust removal main duct is ≤300℃, close the aerosol spray guns of the flue gas branch duct 1, the aerosol spray guns of the 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 of the secondary dust removal main duct is ≤170℃, close one-third (rounded off) of the aerosol spray guns installed in the flue gas main duct; When the flue gas temperature T1 of the secondary dust removal main duct is ≤160℃, turn off the remaining aerosol spray guns installed in the flue gas main duct; The flue gas temperature in the secondary dust removal main pipeline is T1≤110℃, and the air mixing valve 1 and air mixing valve 2 are closed; 3) After the converter oxygen blowing is completed, open the dust removal valve 1 and the dust removal valve 2 at the rear of the furnace, and then close the dust removal valve 1 and the dust removal valve 2 at the front of the furnace. After the converter steel is tapped, open the dust removal valve 1 and the dust removal valve 2 at the front of the furnace, and then close the dust removal valve 1 and the dust removal valve 2 at the rear of the furnace; The cooling water regulating valve used to control the spray gun will increase the cooling water spray flow rate when the detected flue gas temperature rises; The dust collector inlet flue gas temperature T4>100℃, the secondary dust collector high temperature alarm; When the dust collector inlet flue gas temperature T4 is greater than 120°C, the dust removal fan is shut down; At the end of converter production, the dust removal fan runs at low speed.

7. A converter secondary dust removal flue gas cooling method according to claim 6, It is characterized in that The process of opening the aerosol spray gun is: open the compressed air shut-off valve, set the time and then open the water shut-off valve; the process of closing the aerosol spray gun is: Close the water shut-off valve first, and then close the compressed air shut-off valve after the set time.

Images