A method for supplying air to a hydrogen-rich carbon cycle oxygen blast furnace during long-term air stop

Abstract

The present invention relates to an air supply method for a long-term wind stop of a hydrogen-rich carbon cycle oxygen blast furnace. Before the wind stop, the air supply mode is converted from a hot coal gas, cold oxygen, and security nitrogen mixed air supply mode to a hot compressed air, hot oxygen, and hot nitrogen mixed air supply mode. In the hot compressed air, hot oxygen, and hot nitrogen mixed air supply mode, the wind is stopped after running for at least one smelting cycle. At the initial stage of re-winding, half of the tuyere is opened and half of the tuyere is blocked. The air supply mode during the re-winding process adopts: a hot compressed air, hot oxygen, and hot nitrogen mixed air supply mode. When the iron tapping is normal, the material line operates normally, and the number of tuyere openings accounts for more than 80% of the total number of tuyere, the hot compressed air, hot oxygen, and hot nitrogen mixed air supply mode is converted to a hot coal gas, cold oxygen, and security nitrogen mixed air supply mode. The method solves the problems of the difficulty and slow recovery of the tuyere dead zone of the hydrogen-rich carbon cycle oxygen blast furnace after a long-term wind stop, the easy recurrence, the easy burning of the tuyere air supply device, and the furnace cooling.

Description

Technical Field

[0001] The invention belongs to the technical field of blast furnace ironmaking, and in particular is an air supply method for a long-term air stop of a hydrogen-rich carbon circulating oxygen blast furnace. Background Art

[0002] When a hydrogen-rich carbon circulating oxygen blast furnace is stopped for a long time or abnormal furnace conditions such as furnace freezing and furnace cooling occur, the conventional operation method of the hydrogen-rich carbon circulating oxygen blast furnace is to send safety nitrogen for purging, then introduce cold oxygen for ignition, and then introduce mixed injection coal gas, increase the amount of mixed injection coal gas, and reduce the amount of nitrogen. In this process, due to excessively high oxygen content in the blast, inactive furnace, short tuyere swirl zone, high metallization rate of full oxygen injection coal gas smelting, the tuyere air supply device is easily burned, so using this method to restore the furnace condition of the hydrogen-rich carbon circulating oxygen blast furnace can easily aggravate the deterioration of the furnace condition, and repeated suspension of air supply is prone to occur during the recovery of the furnace condition. Summary of the invention

[0003] The purpose of the present invention is to provide an air supply method for a hydrogen-rich carbon cycle oxygen blast furnace that has been shut down for a long time. This method can effectively solve the problem that when the conventional re-airing method of the hydrogen-rich carbon cycle oxygen blast furnace is used to restore the furnace condition of the hydrogen-rich carbon cycle oxygen blast furnace, the furnace condition is easily aggravated. The problem of repeated air supply shutdown is prone to occur during the furnace condition recovery process.

[0004] A method for supplying air to a hydrogen-rich carbon cycle oxygen blast furnace during long-term air stop, comprising the following steps:

[0005] S1. Switching of air supply mode before long-term shutdown of hydrogen-rich carbon cycle oxygen blast furnace or when furnace condition is abnormal:

[0006] The normal operating state of the hydrogen-rich carbon circulating oxygen blast furnace is a mixed gas supply mode of hot coal gas, cold oxygen and security nitrogen. Before stopping the wind for at least one smelting cycle, stop spraying hot coal gas and cold oxygen. Before stopping the hot coal gas spraying, the theoretical combustion temperature is controlled between 1900-2400℃ to reduce the pressure of coal gas and oxygen. After stopping the hot coal gas spraying, the oxygen content of the whole air is controlled below 25% to reduce oxygen until the oxygen is stopped. Process:

[0007] Open the security nitrogen regulating valve 44, open the first security nitrogen cut-off valve 22 and the second security nitrogen cut-off valve 23, and control the security nitrogen flow rate to 5000m 3 / h.

[0008] Stop spraying hot gas: adjust the mixed gas pipeline regulating valve 43, reduce the mixed gas until the regulating valve opening is 0, close the first mixed gas pipeline cut-off valve 27, open the mixed gas pipeline nitrogen purge cut-off valve 30, purge for 1 minute, close the second mixed gas pipeline cut-off valve 28, open the first mixed gas pipeline vent valve 32 and the second mixed gas pipeline vent valve 33, close the mixed gas pipeline nitrogen purge cut-off valve 30, and close the mixed gas pipeline blind valve 31.

[0009] Stop spraying cold oxygen.

[0010] Blowing hot compressed air: confirm that the first compressed air pipeline shut-off valve 2 and the second compressed air pipeline shut-off valve 3 are in the closed state, open the compressed air pipeline blind valve 4, close the first compressed air pipeline bleed valve 5 and the second compressed air pipeline bleed valve 6, open the first compressed air pipeline shut-off valve 2 and the first compressed air pipeline shut-off valve 3, and regulate the compressed air flow through the compressed air pipeline regulating valve 41.

[0011] Injecting hot oxygen: confirm that the first hot oxygen pipeline shut-off valve 12 and the second hot oxygen pipeline shut-off valve 13 are in the closed state, open the hot oxygen pipeline blind valve 14, close the first hot oxygen pipeline vent valve 15 and the second hot oxygen pipeline vent valve 16, open the first hot oxygen pipeline shut-off valve 12 and the second hot oxygen pipeline shut-off valve 13, and regulate the hot oxygen flow rate through the hot oxygen pipeline regulating valve 42.

[0012] Adjust air supply parameters: adjust the flow rates of compressed air, hot oxygen and nitrogen to the required values, and during this period, the oxygen content of the total mixed gas is controlled between 21% and 25%; in this air supply mode, the blast furnace will be shut down after at least one smelting cycle.

[0013] S2. Rewind:

[0014] When re-airing after a long period of shutdown or abnormal furnace condition, make sure to open half of the tuyere close to the iron mouth, block the other half of the tuyere far from the iron mouth, and resume air in half of the tuyere. During the re-airing process, still choose the mixed gas air supply mode of hot compressed air, hot oxygen and security nitrogen: first send security nitrogen, purge the system for 1 minute, and operate according to the sequence of S1 blowing hot compressed air and blowing hot oxygen and adjust the air supply parameters. During the re-airing process, the oxygen content of the whole air is controlled between 21% and 25%. After re-airing, the furnace condition is restored under this air supply mode.

[0015] S3. Switch the air supply mode after the furnace condition is restored:

[0016] When the furnace condition gradually recovers, the furnace temperature tends to be normal, the iron tapping in front of the furnace tends to be normal, the charge unloading is normal, and the number of tuyere openings accounts for more than 80% of the total number of tuyere openings, the mixed gas supply mode of hot compressed air, hot oxygen, and security nitrogen is switched to the mixed gas supply mode of hot coal gas, cold oxygen, and security nitrogen. The process is as follows:

[0017] Stop spraying hot oxygen: open the hot oxygen pipeline nitrogen purge valve 18, adjust the hot oxygen pipeline regulating valve 42 to reduce the hot oxygen until the hot oxygen flow is 0, close the first hot oxygen pipeline cut-off valve 12 and the second hot oxygen pipeline cut-off valve 13, open the first hot oxygen pipeline vent valve 15 and the second hot oxygen pipeline vent valve 16, close the hot oxygen pipeline nitrogen purge valve 18, and close the hot oxygen pipeline blind valve 14.

[0018] Stop spraying hot compressed air: after stopping the hot oxygen, open the compressed air pipeline nitrogen purge valve 8, adjust the compressed air pipeline regulating valve 41 to reduce the compressed air until the compressed air flow is 0, close the first compressed air pipeline cut-off valve 2 and the second compressed air pipeline cut-off valve 3, open the first compressed air pipeline vent valve 5 and the second compressed air pipeline vent valve 6, close the compressed air pipeline nitrogen purge valve 8, and close the compressed air pipeline blind plate valve 4.

[0019] Injecting cold oxygen: send cold oxygen into the blast furnace tuyere, and adjust the amount of cold oxygen injected. During this period, the oxygen content of the total mixed gas is controlled between 21%-25%. After the cold oxygen injection amount is increased to the maximum under the condition that the oxygen content of the total air is controlled between 21%-25%, it is confirmed that the blast furnace is operating normally.

[0020] Inject hot coal gas: confirm that the first mixed coal gas pipeline shut-off valve 27 and the second mixed coal gas pipeline shut-off valve 28 are closed, open the mixed coal gas pipeline blind valve 31, open the mixed coal gas pipeline nitrogen purge shut-off valve 30, close the first mixed coal gas pipeline vent valve 32 and the second mixed coal gas pipeline vent valve 33, open the first mixed coal gas pipeline shut-off valve 27 and the second mixed coal gas pipeline shut-off valve 28, adjust the mixed coal gas pipeline regulating valve 43, and gradually increase the mixed coal gas injection volume until the operation and production requirements are met. When the mixed coal gas injection volume exceeds 5000m 3 / h later, close the nitrogen purge cut-off valve 30 of the mixed gas pipeline.

[0021] The heat storage capacity of the hydrogen-rich carbon cycle oxygen blast furnace is much weaker than that of the traditional blast furnace. Therefore, in the process of dealing with abnormal furnace conditions such as long-term shutdown of the hydrogen-rich carbon cycle oxygen blast furnace and freezing of the furnace hearth or cooling of the furnace, the present invention switches from the previous cycle before the shutdown to the hot compressed air, hot oxygen, and hot nitrogen mixed gas air supply mode. This mode is similar to the air supply mode of traditional blast furnace smelting, which can greatly reduce the indirect reduction reaction in the furnace, reduce the metallization rate of the charge, supplement coke instead of injecting coal gas, increase the range of the furnace hearth coke bed, increase the air permeability of the blast furnace, and easily obtain good air permeability of the blast furnace after re-airing, thereby improving the furnace hearth. Activity, after re-airing, half of the tuyere is opened and half of the tuyere is blocked, which can reduce the probability of burning and leakage of the tuyere air supply device due to the inactivity of the furnace. The re-air supply mode selects hot compressed air, hot oxygen, and hot nitrogen mixed air supply mode to better control the local blast oxygen content and smelting intensity of the furnace. As the furnace activity and the air permeability of the hydrogen-rich carbon cycle oxygen blast furnace gradually improve, the blocked tuyere is gradually opened. When the number of tuyere openings is more than 80%, it can be considered that the blast furnace is capable of switching to the conventional smelting mode of the hydrogen-rich carbon cycle oxygen blast furnace, and then the air supply mode is switched. Compared with the conventional air supply mode of the conventional hydrogen-rich carbon cycle oxygen blast furnace, the method of the present invention has a stronger advantage in restoring the furnace condition of the hydrogen-rich carbon cycle oxygen blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flow chart of the air supply mode switching system of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined Figure 1 The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1As shown, the present invention provides an air supply method for a long-term shutdown of a hydrogen-rich carbon cycle oxygen blast furnace, and its air supply mode switching system includes: a compressed air supply pipeline 1, a first compressed air pipeline shut-off valve 2, a second compressed air pipeline shut-off valve 3, a compressed air pipeline blind plate valve 4, a first compressed air pipeline release valve 5, a second compressed air pipeline release valve 6, a compressed air pipeline purging nitrogen pipeline 7, a compressed air pipeline purging nitrogen valve 8, a compressed air pipeline pressure gauge 9, a compressed air pipeline flow meter 10, a hot oxygen supply pipeline 11, a first hot oxygen pipeline shut-off valve 12, a second hot oxygen pipeline shut-off valve 13, a hot oxygen pipeline blind plate valve 14, a first hot oxygen pipeline release valve 15, a second hot oxygen pipeline release valve 16, a hot oxygen pipeline purging nitrogen pipeline 17, a hot oxygen pipeline purging nitrogen valve 18, a hot oxygen pipeline pressure gauge 19, and a hot oxygen pipeline flow meter 20. Security nitrogen pipeline 21, first security nitrogen shut-off valve 22, second security nitrogen shut-off valve 23, security nitrogen pipeline pressure gauge 24, security nitrogen flowmeter 25, mixed gas pipeline 26, first mixed gas pipeline shut-off valve 27, second mixed gas pipeline shut-off valve 28, mixed gas pipeline purge nitrogen pipeline 29, mixed gas pipeline purge nitrogen shut-off valve 30, mixed gas pipeline blind plate valve 31, first mixed gas pipeline vent valve 32, second mixed gas pipeline vent valve 33, mixed gas pipeline pressure gauge 34, mixed gas pipeline flowmeter 35, total mixed gas pipeline 36, total mixed gas pipeline gas analyzer 37, gas heating furnace 38, cold oxygen pipeline 39, hydrogen-rich carbon cycle oxygen blast furnace 40, compressed air pipeline regulating valve 41, hot oxygen pipeline regulating valve 42, mixed gas pipeline regulating valve 43, security nitrogen pipeline regulating valve 44;

[0025] The first compressed air pipeline shut-off valve 2 is at the starting end of the compressed air supply pipeline 1, the compressed air pipeline blind valve 4 is on the compressed air supply pipeline 1, one position after the first compressed air pipeline shut-off valve 2, the second compressed air pipeline shut-off valve 3 is on the compressed air supply pipeline 1, one position after the compressed air pipeline blind valve 4, the first compressed air pipeline release valve 5 is on the compressed air supply pipeline 1, between the first compressed air pipeline shut-off valve 2 and the compressed air pipeline blind valve 4, the second compressed air pipeline release valve 6 is on the compressed air supply pipeline 1, between the compressed air pipeline blind valve 4 and the second compressed air pipeline The compressed air pipeline pressure gauge 9 is on the compressed air supply pipeline 1, one position after the second compressed air pipeline cut-off valve 3, the compressed air pipeline flow meter 10 is on the compressed air supply pipeline 1, one position after the compressed air pipeline pressure gauge 9, the compressed air pipeline purge nitrogen pipeline 7 and the compressed air pipeline flow meter 10 are connected to the compressed air supply pipeline 1, the compressed air pipeline purge nitrogen valve 8 is on the compressed air pipeline purge nitrogen pipeline 7, the end of the compressed air supply pipeline 1 is connected to the total mixed gas pipeline 36, one position before the connection point between the hot oxygen supply pipeline 11 and the total mixed gas pipeline 36;

[0026] The first hot oxygen pipeline shut-off valve 12 is at the beginning of the hot oxygen gas supply pipeline 11, the hot oxygen pipeline blind valve 14 is on the hot oxygen gas supply pipeline 11, one position after the first hot oxygen pipeline shut-off valve 12, the second hot oxygen pipeline shut-off valve 13 is on the hot oxygen gas supply pipeline 11, one position after the hot oxygen pipeline blind valve 14, the first hot oxygen pipeline vent valve 15 is on the hot oxygen gas supply pipeline 11, between the first hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline blind valve 14, the second hot oxygen pipeline vent valve 16 is on the hot oxygen gas supply pipeline 11, between the hot oxygen pipeline blind valve 14 and the second hot oxygen pipeline shut-off valve 1 3, the hot oxygen pipeline pressure gauge 19 is on the hot oxygen gas supply pipeline 11, one position after the second hot oxygen pipeline shut-off valve 13, the hot oxygen pipeline flow meter 20 is on the hot oxygen gas supply pipeline 11, one position after the hot oxygen pipeline pressure gauge 19, the hot oxygen pipeline purge nitrogen pipeline 17 is connected to the hot oxygen gas supply pipeline 11 one position after the hot oxygen pipeline flow meter 20, the hot oxygen pipeline purge nitrogen valve 18 is on the hot oxygen pipeline purge nitrogen pipeline 17, the end of the hot oxygen gas supply pipeline 11 is connected to the total mixed gas pipeline 36, one position before the connection point between the total mixed gas pipeline coal gas analyzer 37 and the total mixed gas pipeline 36;

[0027] Mixed gas pipeline 26, first mixed gas pipeline cut-off valve 27, second mixed gas pipeline cut-off valve 28, mixed gas pipeline nitrogen purge pipeline 29, mixed gas pipeline nitrogen purge cut-off valve 30, mixed gas pipeline blind valve 31, first mixed gas pipeline relief valve 32, second mixed gas pipeline relief valve 33, mixed gas pipeline pressure gauge 34, mixed gas pipeline flow meter 35;

[0028] The first mixed gas pipeline shut-off valve 27 is installed at the beginning of the mixed gas pipeline 26, the mixed gas pipeline blind valve 31 is installed on the mixed gas pipeline 26, one position after the first mixed gas pipeline shut-off valve 27, the second mixed gas pipeline shut-off valve 28 is installed on the mixed gas pipeline 26, one position after the mixed gas pipeline blind valve 31, the first mixed gas pipeline venting valve 32 is installed on the mixed gas pipeline 26, the position between the first mixed gas pipeline shut-off valve 27 and the mixed gas pipeline blind valve 31, the second mixed gas pipeline venting valve 33 is installed on the mixed gas pipeline 26, the mixed gas pipeline blind valve 31 and the second mixed gas pipeline A mixed gas pipeline pressure gauge 34 is installed on the mixed gas pipeline 26 at a position after the second mixed gas pipeline cut-off valve 28, a mixed gas pipeline flowmeter 35 is installed on the mixed gas pipeline 26, a mixed gas pipeline pressure gauge 34 is installed at a position after the mixed gas pipeline flowmeter 35, a mixed gas pipeline purge nitrogen pipeline 29 is installed at a position after the mixed gas pipeline flowmeter 35 and is connected to the mixed gas pipeline 26, a mixed gas pipeline purge nitrogen cut-off valve 30 is installed on the mixed gas pipeline purge nitrogen pipeline 29, the end of the mixed gas pipeline 26 is connected to the end of the security nitrogen pipeline 21, and is connected to the beginning of the total mixed gas pipeline 36.

[0029] At the beginning of the safety nitrogen pipeline 21, a safety nitrogen pipeline pressure gauge 24 and a safety nitrogen flowmeter 25 are installed in sequence. On the safety nitrogen pipeline 21, a first safety nitrogen cut-off valve 22 and a second safety nitrogen cut-off valve 23 are installed in sequence after the safety nitrogen flowmeter 25. The end of the safety nitrogen pipeline 21 is connected to the end of the mixed gas pipeline 26 and is connected to the beginning of the total mixed gas pipeline 36.

[0030] The end of the total mixed gas pipeline 36 is connected to the gas heating furnace, and the total mixed gas pipeline gas analyzer 37 is connected to the total mixed gas pipeline 36 in front of the gas heating furnace.

[0031] The present invention provides the following technical implementation scheme:

[0032] A method for supplying air to a hydrogen-rich carbon cycle oxygen blast furnace for long-term air stoppage or treatment of abnormal furnace conditions, comprising the following steps:

[0033] S1. Switching of air supply mode before long-term shutdown of hydrogen-rich carbon cycle oxygen blast furnace or abnormal furnace condition (cooling furnace, frozen furnace cylinder, etc.):

[0034] The normal operating state of the hydrogen-rich carbon circulating oxygen blast furnace is a mixed gas supply mode of hot coal gas, cold oxygen and security nitrogen. Before stopping the wind for at least one smelting cycle, stop spraying hot coal gas and cold oxygen. Before stopping the hot coal gas spraying, the theoretical combustion temperature is controlled between 1900-2400℃ to reduce the pressure of coal gas and oxygen. After stopping the hot coal gas spraying, the oxygen content of the whole air is controlled below 25% to reduce oxygen until the oxygen is stopped. Process:

[0035] Open the security nitrogen regulating valve 44, open the first security nitrogen cut-off valve 22 and the second security nitrogen cut-off valve 23, and control the security nitrogen flow rate to 5000m 3 / h.

[0036] Stop spraying hot gas: adjust the mixed gas pipeline regulating valve 43, reduce the mixed gas until the regulating valve opening is 0, close the first mixed gas pipeline cut-off valve 27, open the mixed gas pipeline nitrogen purge cut-off valve 30, purge for 1 minute, close the second mixed gas pipeline cut-off valve 28, open the first mixed gas pipeline vent valve 32 and the second mixed gas pipeline vent valve 33, close the mixed gas pipeline nitrogen purge cut-off valve 30, and close the mixed gas pipeline blind valve 31.

[0037] Stop spraying cold oxygen.

[0038] Blowing hot compressed air: confirm that the first compressed air pipeline shut-off valve 2 and the second compressed air pipeline shut-off valve 3 are in the closed state, open the compressed air pipeline blind valve 4, close the first compressed air pipeline vent valve 5 and the second compressed air pipeline vent valve 6, open the first compressed air pipeline shut-off valve 2 and the second compressed air pipeline shut-off valve 3, and regulate the compressed air flow through the compressed air pipeline regulating valve 41.

[0039] Injecting hot oxygen: confirm that the first hot oxygen pipeline shut-off valve 12 and the second hot oxygen pipeline shut-off valve 13 are in the closed state, open the hot oxygen pipeline blind valve 14, close the first hot oxygen pipeline vent valve 15 and the second hot oxygen pipeline vent valve 16, open the first hot oxygen pipeline shut-off valve 12 and the second hot oxygen pipeline shut-off valve 13, and regulate the hot oxygen flow rate through the hot oxygen pipeline regulating valve 42.

[0040] Adjust air supply parameters: adjust the flow rates of compressed air, hot oxygen and nitrogen to the required values, and during this period, the oxygen content of the total mixed gas is controlled between 21% and 25%; in this air supply mode, the blast furnace will be shut down after at least one smelting cycle.

[0041] S2. Rewind:

[0042] When re-airing after a long period of shutdown or abnormal furnace condition, make sure to open half of the tuyere close to the iron mouth, block the other half of the tuyere far from the iron mouth, and resume air in half of the tuyere. During the re-airing process, still choose the mixed gas air supply mode of hot compressed air, hot oxygen and security nitrogen: first send security nitrogen, purge the system for 1 minute, and operate according to the sequence of S1 blowing hot compressed air and blowing hot oxygen and adjust the air supply parameters. During the re-airing process, the oxygen content of the whole air is controlled between 21% and 25%. After re-airing, the furnace condition is restored under this air supply mode.

[0043] S3. Switch the air supply mode after the furnace condition is restored:

[0044] When the furnace condition gradually recovers, the furnace temperature tends to be normal, the iron tapping in front of the furnace tends to be normal, the charge unloading is normal, and the number of tuyere openings accounts for more than 80% of the total number of tuyere openings, the mixed gas supply mode of hot compressed air, hot oxygen, and security nitrogen is switched to the mixed gas supply mode of hot coal gas, cold oxygen, and security nitrogen. The process is as follows:

[0045] Stop spraying hot oxygen: open the hot oxygen pipeline nitrogen purge valve 18, adjust the hot oxygen pipeline regulating valve 42 to reduce the hot oxygen until the hot oxygen flow is 0, close the second hot oxygen pipeline cut-off valve 12 and the second hot oxygen pipeline cut-off valve 13, open the first hot oxygen pipeline vent valve 15 and the second hot oxygen pipeline vent valve 16, close the hot oxygen pipeline nitrogen purge valve 18, and close the hot oxygen pipeline blind valve 14.

[0046] Stop spraying hot compressed air: after stopping the hot oxygen, open the compressed air pipeline nitrogen purge valve 8, adjust the compressed air pipeline regulating valve 41 to reduce the compressed air until the compressed air flow is 0, close the first compressed air pipeline cut-off valve 2 and the second compressed air pipeline cut-off valve 3, open the first compressed air pipeline vent valve 5 and the second compressed air pipeline vent valve 6, close the compressed air pipeline nitrogen purge valve 8, and close the compressed air pipeline blind plate valve 4.

[0047] Injecting cold oxygen: send cold oxygen into the blast furnace tuyere, and adjust the amount of cold oxygen injected. During this period, the oxygen content of the total mixed gas is controlled between 21%-25%. After the cold oxygen injection amount is increased to the maximum under the condition that the oxygen content of the total air is controlled between 21%-25%, it is confirmed that the blast furnace is operating normally.

[0048] Inject hot coal gas: confirm that the first mixed coal gas pipeline shut-off valve 27 and the second mixed coal gas pipeline shut-off valve 28 are closed, open the mixed coal gas pipeline blind valve 31, open the mixed coal gas pipeline nitrogen purge shut-off valve 30, close the first mixed coal gas pipeline vent valve 32 and the second mixed coal gas pipeline vent valve 33, open the first mixed coal gas pipeline shut-off valve 27 and the second mixed coal gas pipeline shut-off valve 28, adjust the mixed coal gas pipeline regulating valve 43, and gradually increase the mixed coal gas injection volume until the operation and production requirements are met. When the mixed coal gas injection volume exceeds 5000m 3 / h later, close the nitrogen purge cut-off valve 30 of the mixed gas pipeline.

[0049] Example

[0050] The following is an example of restoring furnace conditions using the above method, taking the Xinjiang Bagang low-carbon test platform HY blast furnace as the implementation object.

[0051] The scheduled maintenance of the HY blast furnace operation area of ​​the hydrogen-rich carbon cycle oxygen blast furnace process was completed at 11:15 on May 25, 2023. The main maintenance items of this scheduled maintenance include partial replacement of the tuyere air supply device, re-making of the main ditch, overall replacement of the mud gun, and replacement of the slag flushing duckbill. The total time for the scheduled maintenance was 1575 minutes from 9:00 on the 24th to 11:15 on the 25th.

[0052] The structure of blast furnace blast material on May 24 is as follows:

[0053] ;

[0054] Iron production in the smelting cycle before the shutdown on May 24:

[0055] ;

[0056] During the blast furnace re-airing process after the scheduled maintenance on the 25th, the blast furnace charging pattern was: 2P 24.5°6 turns↓2K 24.5°6 turns↓Charging line: 1.6m.

[0057] The blast furnace re-airing method adopts: nitrogen, cold oxygen, hot coal gas mixed gas injection re-airing method, the tuyere is fully opened for air supply (14 tuyere), and the re-air supply parameter setting is:

[0058] ;

[0059] After the blast furnace was blasted at 11:50 on the 25th, the iron tapping situation in front of the furnace was as follows:

[0060] ;

[0061] At 11:50 on the 25th, the wind was turned on. At 12:18, the south probe was 1.42 meters and the north probe was 1.24 meters. The material line continued to be inactive. It was judged that the blast furnace was overfilled. The hot air pressure was 155kpa and the pressure difference was 84kpa. At 14:27, the material suddenly collapsed. The south probe was 1.42 meters and the north probe was 1.24 meters, which changed to the south probe 2.47 meters and the north probe 2.32 meters. The hot air pressure was 117kpa and the pressure difference was 31kpa.

[0062] After the material collapse, it was found that the liquid level in the expansion tank of the blast furnace dropped rapidly, and the amount of soft water replenishment increased. At the same time, the inspection of the water flow trend of the small jackets found that the 2#3#6# small jackets had leakage characteristics, and the difference between the inlet and outlet water volume increased to 7L / min. The cooling water system of the blast furnace was inspected on site, and it was confirmed that the 4# and 5# large jackets were leaking, and the 2#3#6# small jackets were leaking. The blast furnace was shut down at 20:05 on the 25th. A total of 26 batches of material were added after the resumption of the wind.

[0063] At 20:05 on the 25th, the 4# and 5# large sets, and the 2#3#4#5#6# small sets were replaced during the shutdown. A total of 31.67m³ of soft water was used to replenish the air until the shutdown. At 13:40 on the 26th, the air supply device with water leakage in the tuyere was replaced, and the blast furnace was restored. During this restoration process, the parameters of the blast furnace distribution system are: ore batch weight: 14.5t coke batch weight: 4.78t coke ratio: 515.3Kg / t load: 3.021, distribution mode: 2P 24.5°6 turns↓2K24.5°6 turns↓ material line: 1.6m. The blast furnace restoration method adopts: nitrogen, cold oxygen, hot coal gas mixed gas injection restoration method, 11 tuyere air supply, restoration air supply parameter settings:

[0064] ;

[0065] After the air was restored, the iron mouth was opened once at about 15:00, and a small amount of red slag iron sprayed out, and the iron mouth sprayed out, and then the mouth was blocked. Number of air supply tuyere: 11, 3#4#5# tuyere blocked with taphole mud, the tuyere operated normally after air supply, and the material line moved slowly. At 15:07 on the 26th, the blast furnace began to spray coke oven gas. At 15:08, a small pipe appeared in the blast furnace, and the top pressure rose to: 184kpa, top temperature: 135℃, after the pipe, the north probe 1.94m, the south probe 2.24m suddenly increased to the north probe 4.08m, the south probe 3.86m, and then it was found that the water flow rate of the tuyere small sleeve 6#7#8#9#11# was abnormal, and the liquid level of the blast furnace expansion tank dropped rapidly. Notify the water to observe the tuyere, and the tuyere is restored to black. On-site inspection found that the 6#7#8#9#11# small sleeve and the 6# large sleeve were leaking. At 16:20, the air was stopped and the damaged air supply device was replaced.

[0066] At 8:18 am on the 27th, all positions jointly decided to handle the accident as a furnace cooling. On the 27th, the day shift oxygen burned 1#14# tuyere (replaced 1#2#13#14# small sleeves with double-cavity small sleeves), and buried oxygen guns at the iron mouth. At 20:25 on the 27th, the blast furnace was opened again. The parameters of the blast furnace burden distribution system were: ore batch weight: 12t, coke batch weight: 5.3t, coke ratio: 698Kg / t, load: 2.26, burden distribution mode: 2P23.5°6 turns↓3K 23.5°8 turns↓Fuel line: 1.6m.

[0067] The blast furnace re-airing method is: nitrogen, hot oxygen, hot compressed air mixed injection re-airing method, this time the number of air supply tuyere: 4, use 1#, 2#, 13#, 14# tuyere for air supply, the other tuyere are blocked with refractory bricks and cement, the tuyere extra nitrogen is completely closed, BP: 170kpa, wind speed ≥200m / s, pressure difference ≤140kpa, blast oxygen content does not exceed 25%. This re-airing air supply parameter setting:

[0068] ;

[0069] At around 3:20 on the 28th, on-site inspection revealed that the front cavity of the 13# small sleeve was leaking. The water was controlled to 7.5m³, and nitrogen was passed through the tuyere for maintenance. The blast furnace condition slowly recovered. At around 18:00 on the 28th, a small pit was put into use in front of the furnace for iron tapping, and iron tapping returned to normal. At around 6:30 on the 29th, all tuyere except 8#9# tuyere were opened. At around 18:00, cold oxygen was delivered to the blast furnace tuyere, at around 19:00, decarbonized coal gas was delivered to the blast furnace, and at around 23:00, coke oven gas was delivered to the blast furnace. At this point, the blast furnace cooling was basically handled, and the operating parameters were gradually restored. By the 30th, the operating parameters of the hydrogen-rich carbon circulating oxygen blast furnace were basically restored to normal levels, and the blast furnace Si dropped to 0.74, and the blast furnace accident disposal was over.

Claims

1. A method for supplying air to a hydrogen-rich carbon cycle oxygen blast furnace during long-term air stop, characterized in that: The steps include: S1. Switching of air supply mode before long-term shutdown of hydrogen-rich carbon cycle oxygen blast furnace or when furnace condition is abnormal: The normal operating state of the hydrogen-rich carbon cycle oxygen blast furnace is a mixed gas supply mode of hot coal gas, cold oxygen and security nitrogen. Before stopping the wind for at least one smelting cycle, stop spraying hot coal gas and cold oxygen. Before stopping the hot coal gas spraying, the theoretical combustion temperature is controlled between 1900-2400℃ to carry out the pressure reduction operation of reducing coal gas and oxygen. After stopping the hot coal gas spraying, the oxygen content of the whole air is controlled below 25% to carry out the oxygen reduction operation until the oxygen is stopped; process: Open the security nitrogen regulating valve (44), open the first security nitrogen shut-off valve (22) and the second security nitrogen shut-off valve (23), and control the security nitrogen flow rate to 5000m 3 / h; Stop spraying hot gas: adjust the mixed gas pipeline regulating valve (43), reduce the mixed gas until the regulating valve opening is 0, close the first mixed gas pipeline shut-off valve (27), open the mixed gas pipeline nitrogen purge shut-off valve (30), purge for 1 minute, close the second mixed gas pipeline shut-off valve (28), open the first mixed gas pipeline vent valve (32) and the second mixed gas pipeline vent valve (33), close the mixed gas pipeline nitrogen purge shut-off valve (30), and close the mixed gas pipeline blind valve (31); Stop spraying cold oxygen; Blowing hot compressed air: confirm that the first compressed air pipeline shut-off valve (2) and the second compressed air pipeline shut-off valve (3) are in a closed state, open the compressed air pipeline blind valve (4), close the first compressed air pipeline relief valve (5) and the second compressed air pipeline relief valve (6), open the first compressed air pipeline shut-off valve (2) and the second compressed air pipeline shut-off valve (3), and adjust the compressed air flow rate through the compressed air pipeline regulating valve (41); Injecting hot oxygen: confirm that the first hot oxygen pipeline shut-off valve (12) and the second hot oxygen pipeline shut-off valve (13) are in the closed state, open the hot oxygen pipeline blind valve (14), close the first hot oxygen pipeline vent valve (15) and the second hot oxygen pipeline vent valve (16), open the first hot oxygen pipeline shut-off valve (12) and the second hot oxygen pipeline shut-off valve (13), and control the hot oxygen flow rate through the hot oxygen pipeline regulating valve (42); Adjust air supply parameters: adjust the flow rates of compressed air, hot oxygen and nitrogen to the required values, and during this period, the oxygen content of the total mixed air is controlled between 21% and 25%; in this air supply mode, the blast furnace is shut down after at least one smelting cycle; S2. Rewind: When re-airing after a long-term shutdown or abnormal furnace condition, confirm to open half of the tuyere close to the taphole before re-airing, block the other half of the tuyere far from the taphole, and re-air half of the tuyere. During the re-airing process, select the mixed gas supply mode of hot compressed air, hot oxygen, and security nitrogen: first send security nitrogen, purge the system for 1 minute, operate according to the sequence of S1 spraying hot compressed air and spraying hot oxygen and adjust the air supply parameters. During the re-airing process, the oxygen content of the whole air is controlled between 21% and 25%. After re-airing, the furnace condition is restored under this air supply mode; S3. Switch the air supply mode after the furnace condition is restored: When the furnace condition gradually recovers, the furnace temperature tends to be normal, the iron tapping in front of the furnace tends to be normal, the charge unloading is normal, and the number of tuyere openings accounts for more than 80% of the total number of tuyere openings, the mixed gas supply mode of hot compressed air, hot oxygen, and security nitrogen is switched to the mixed gas supply mode of hot coal gas, cold oxygen, and security nitrogen. The process is as follows: Stop spraying hot oxygen: open the hot oxygen pipeline nitrogen purge valve (18), adjust the hot oxygen pipeline regulating valve (42) to reduce the hot oxygen until the hot oxygen flow rate is 0, close the first hot oxygen pipeline shut-off valve (12) and the second hot oxygen pipeline shut-off valve (13), open the first hot oxygen pipeline vent valve (15) and the second hot oxygen pipeline vent valve (16), close the hot oxygen pipeline nitrogen purge valve (18), and close the hot oxygen pipeline blind valve (14); Stop spraying hot compressed air: after stopping the hot oxygen, open the compressed air pipeline nitrogen purge valve (8), adjust the compressed air pipeline regulating valve (41) to reduce the compressed air until the compressed air flow is 0, close the first compressed air pipeline shut-off valve (2) and the second compressed air pipeline shut-off valve (3), open the first compressed air pipeline vent valve (5) and the second compressed air pipeline vent valve (6), close the compressed air pipeline nitrogen purge valve (8), and close the compressed air pipeline blind valve (4); Cold oxygen injection: cold oxygen is introduced into the blast furnace tuyere, and the amount of cold oxygen injection is adjusted. During this period, the oxygen content of the total mixed gas is controlled between 21% and 25%. When the amount of cold oxygen injection is increased to the maximum under the condition that the oxygen content of the total air is controlled between 21% and 25%, it is confirmed that the blast furnace is operating normally; Injecting hot coal gas: confirm that the first mixed coal gas pipeline shut-off valve (27) and the second mixed coal gas pipeline shut-off valve (28) are in the closed state, open the mixed coal gas pipeline blind valve (31), open the mixed coal gas pipeline nitrogen purge shut-off valve (30), close the first mixed coal gas pipeline vent valve (32) and the second mixed coal gas pipeline vent valve (33), open the first mixed coal gas pipeline shut-off valve (27) and the second mixed coal gas pipeline shut-off valve (28), adjust the mixed coal gas pipeline regulating valve (43), and gradually increase the mixed coal gas injection volume until the operation and production requirements are met. When the mixed coal gas injection volume exceeds 5000m 3 / h later, close the nitrogen purge cut-off valve (30) of the mixed gas pipeline.

2. The air supply method for a long-term air stop of a hydrogen-rich carbon cycle oxygen blast furnace according to claim 1, characterized in that: The hot oxygen pressure is controlled at 0.55-0.6MPa by the pressure gauge of the hot oxygen pipeline, the compressed air pressure is controlled at 0.55-0.6MPa by the pressure gauge of the compressed air pipeline, the mixed gas pressure is controlled at 0.55-0.6MPa by the pressure gauge of the mixed gas pipeline, and the security nitrogen pressure is controlled at 0.6-0.65MPa by the pressure gauge of the security nitrogen pipeline.

3. The air supply method for a long-term air stop of a hydrogen-rich carbon cycle oxygen blast furnace according to claim 1, characterized in that: Set interlock protection to ensure that nitrogen pressure - compressed air pressure is greater than 0.05MPa, otherwise the compressed air regulating valve and cut-off valve will all be automatically interlocked and closed.

4. The air supply method for a long-term air stop of a hydrogen-rich carbon cycle oxygen blast furnace according to claim 1, characterized in that: Set interlocking protection to ensure that nitrogen pressure - hot oxygen pressure is greater than 0.05MPa, otherwise the hot oxygen regulating valve and cut-off valve will all be automatically interlocked and closed.

5. The air supply method for a long-term air stop of a hydrogen-rich carbon cycle oxygen blast furnace according to claim 1, characterized in that: Set interlock protection to ensure that nitrogen pressure - mixed gas pressure is greater than 0.05MPa, otherwise the mixed gas regulating valve and cut-off valve will all be automatically interlocked and closed.

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