Air supply method for long-term blowing-down of hydrogen-enriched carbonic oxide recycling oxygenate furnace

Abstract

The present invention relates to an air supply method for long-term blowing-down of a hydrogen-enriched carbonic oxide recycling oxygenate furnace. Before blowing down, an air supply mode of delivering a mixture of hot coal gas, cold oxygen, and safety nitrogen is converted into an air supply mode of delivering a mixture of hot compressed air, hot oxygen, and hot nitrogen; in the air supply mode of delivering the mixture of hot compressed air, hot oxygen, and hot nitrogen, the operation is performed for at least one smelting cycle before blowing down; in an initial reblowing period, half of tuyeres are opened while the other half are blocked; in the reblowing process, the air supply mode of delivering the mixture of hot compressed air, hot oxygen, and hot nitrogen is used; and once normal tapping and stockline operation are achieved, and the number of tuyeres opened accounts for 80% or more of the total number of tuyeres, the air supply mode of delivering the mixture of hot compressed air, hot oxygen, and hot nitrogen is converted into the air supply mode of delivering the mixture of hot coal gas, cold oxygen, and safety nitrogen. The method solves the problems of dead zones of tuyeres being difficult to recover and slow to recover after long-term blowing-down of a hydrogen-enriched carbonic oxide recycling oxygenate furnace, repeated blowing-down easily occurring, air supply devices of the tuyeres being prone to burn, the furnace being cool and the like.

Description

A method for supplying air to a hydrogen-rich carbon cycle oxygen blast furnace during long-term air shutdown 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-shutdown hydrogen-rich carbon cycle 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 hearth 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 the high oxygen content of the blast, the inactive furnace hearth, the short tuyere swirl zone, the high metallization rate of the full oxygen injection coal gas smelting, the tuyere air supply device is easily burned, and thus the use of this method to restore the furnace condition of the hydrogen-rich carbon circulating oxygen blast furnace is likely to aggravate the deterioration of the furnace condition, and the problem of repeated suspension of air supply is prone to occur during the furnace condition recovery process. 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, and the problem of repeated air supply shutdown is easily caused during the furnace condition recovery process.

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

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

[0006] The normal operating state of the hydrogen-rich carbon circulating oxygen blast furnace is the mixed gas supply mode of hot coal gas, cold oxygen, and safety nitrogen. Before the air is shut down for at least one smelting cycle, the hot coal gas and cold oxygen injection are stopped. Before the hot coal gas injection is stopped, the theoretical combustion temperature is controlled between 1900-2400℃ and the pressure reduction operation of reducing coal gas and oxygen is carried out. After the hot coal gas injection is stopped, the oxygen content of the whole air is controlled below 25% and the oxygen reduction operation is carried out until the oxygen is stopped. Process:

[0007] Pass the security nitrogen: open the security nitrogen regulating valve 44, open the security nitrogen cut-off valves 22 and 23, and control the security nitrogen flow to 5000m3 / 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 mixed gas pipeline shut-off valve 27, open the mixed gas pipeline nitrogen purge shut-off valve 30, purge for 1 minute, close the mixed gas pipeline shut-off valve 28, open the mixed gas pipeline bleed valve 32 and the mixed gas pipeline bleed valve 33, close the mixed gas pipeline nitrogen purge shut-off valve 30, and close the mixed gas pipeline blind plate valve 31.

[0009] Stop spraying cold oxygen 39.

[0010] Blowing hot compressed air: Confirm that the compressed air pipeline shut-off valve 2 and the compressed air pipeline shut-off valve 3 are closed, open the compressed air pipeline blind valve 4, close the compressed air pipeline release valve 5 and the compressed air pipeline release valve 6, open the compressed air pipeline shut-off valve 2 and the 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 hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline shut-off valve 13 are closed, open the hot oxygen pipeline blind valve 14, close the hot oxygen pipeline release valve 15 and the hot oxygen pipeline release valve 16, open the hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline shut-off valve 13, and regulate the hot oxygen flow 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 control the oxygen content of the total mixed air between 21% and 25% during this period. 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 taphole and block the other half of the tuyere far from the taphole before re-airing. Re-air half of the tuyere, and still select the air supply mode of hot compressed air, hot oxygen and hot nitrogen mixture during the re-airing process: first send security nitrogen to 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] Switch to air supply mode after S3 furnace condition is restored:

[0016] When the furnace condition gradually recovers, the furnace temperature tends to normal, the iron tapping tends to normal, the charge unloading is normal, 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 switched to the hot coal gas, hot oxygen, and security nitrogen mixed air supply mode. 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 hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline shut-off valve 13, open the hot oxygen pipeline bleed valve 15 and the hot oxygen pipeline bleed valve 16, close the hot oxygen pipeline nitrogen purge valve 18, and close the hot oxygen pipeline blind plate 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 compressed air pipeline shut-off valve 2 and the compressed air pipeline shut-off valve 3, open the compressed air pipeline bleed valve 5 and the compressed air pipeline bleed 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: cold oxygen 39 is introduced into the blast furnace tuyere, and the amount of injected cold oxygen is adjusted. During this period, the oxygen content of the total mixed gas is controlled between 21% and 25%. After 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.

[0020] Hot gas injection: Confirm that mixed gas pipeline shutoff valves 27 and 28 are closed. Open the mixed gas pipeline blind valve 31, open the mixed gas pipeline nitrogen purge shutoff valve 30, close the mixed gas pipeline bleed valve 32 and the mixed gas pipeline bleed valve 33, open the mixed gas pipeline shutoff valves 27 and 28, and adjust the mixed gas pipeline regulating valve 43, gradually increasing the mixed gas injection rate until it meets operational production requirements. When the mixed gas injection rate exceeds 5000 m3 / h, close the mixed gas pipeline nitrogen purge shutoff valve 30.

[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 treating the abnormal furnace conditions such as long-term shutdown of the hydrogen-rich carbon cycle oxygen blast furnace and hearth freezing or furnace cooling, the present invention switches from the cycle before the shutdown to the hot compressed air, hot oxygen, and hot nitrogen mixed gas 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 hearth coke bed, increase the permeability of the blast furnace, and easily obtain good permeability of the blast furnace after re-airing, thereby improving the hearth Activity. After re-airing, half of the tuyere is opened and half is blocked. This can reduce the probability of burnout and water leakage of the tuyere air supply device due to hearth inactivity. The re-airing 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 hearth. As the hearth activity and the permeability of the hydrogen-rich carbon cycle oxygen blast furnace gradually improve, the blocked tuyere is gradually opened. When the number of tuyere openings reaches more than 80%, it can be considered that the blast furnace is ready to switch 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 greater advantage in recovering the furnace condition of the hydrogen-rich carbon cycle oxygen blast furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG1 is a flow chart of the air supply mode switching system of the present invention. Implementation Method

[0023] The following description will be made in conjunction with FIG1 to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 making creative efforts are within the scope of protection of the present invention.

[0024] As shown in Figure 1, 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 compressed air pipeline shut-off valve 2, a compressed air pipeline shut-off valve 3, a compressed air pipeline blind plate valve 4, a compressed air pipeline release valve 5, a compressed air pipeline release valve 6, a compressed air pipeline nitrogen purge pipeline 7, a compressed air pipeline nitrogen purge valve 8, a compressed air pipeline pressure gauge 9, a compressed air pipeline flowmeter 10, a hot oxygen supply pipeline 11, a hot oxygen pipeline shut-off valve 12, a hot oxygen pipeline shut-off valve 13, a hot oxygen pipeline blind plate valve 14, a hot oxygen pipeline release valve 15, a hot oxygen pipeline release valve 16, a hot oxygen pipeline nitrogen purge pipeline 17, a hot oxygen pipeline nitrogen purge valve 18, a hot oxygen pipeline pressure gauge 19, a hot oxygen pipeline flowmeter 20, and an installation. Nitrogen preservation pipeline 21, security nitrogen shut-off valve 22, security nitrogen shut-off valve 23, security nitrogen pipeline pressure gauge 24, security nitrogen flowmeter 25, mixed gas pipeline 26, mixed gas pipeline shut-off valve 27, mixed gas pipeline shut-off valve 28, mixed gas pipeline nitrogen purge pipeline 29, mixed gas pipeline nitrogen purge shut-off valve 30, mixed gas pipeline blind plate valve 31, mixed gas pipeline bleed valve 32, mixed gas pipeline bleed 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 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 compressed air pipeline shut-off valve 2, the 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 compressed air pipeline release valve 5 is on the compressed air supply pipeline 1, between the compressed air pipeline shut-off valve 2 and the compressed air pipeline blind valve 4, the compressed air pipeline release valve 6 is on the compressed air supply pipeline 1, between the compressed air pipeline blind valve 4 and the compressed air pipeline shut-off valve 3. The compressed air line pressure gauge 9 is on the compressed air supply line 1, one position after the compressed air line shut-off valve 3, the compressed air line flow meter 10 is on the compressed air supply line 1, one position after the compressed air line pressure gauge 9, the compressed air line purge nitrogen line 7 and the compressed air line flow meter 10 are connected to the compressed air supply line 1, the compressed air line purge nitrogen valve 8 is on the compressed air line purge nitrogen line 7, the end of the compressed air supply line 1 is connected to the total mixed gas line 36, and one position before the connection point between the hot oxygen supply line 11 and the total mixed gas line 36;

[0026] The 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 hot oxygen pipeline shut-off valve 12, the 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 hot oxygen pipeline release valve 15 is on the hot oxygen gas supply pipeline 11, between the hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline blind valve 14, the hot oxygen pipeline release valve 16 is on the hot oxygen gas supply pipeline 11, between the hot oxygen pipeline blind valve 14 and the hot oxygen pipeline shut-off valve 13, the hot oxygen The pipeline pressure gauge 19 is on the hot oxygen gas supply pipeline 11, one position after the hot oxygen pipeline shut-off valve 13. The hot oxygen pipeline flowmeter 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 flowmeter 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 gas analyzer 37 and the total mixed gas pipeline 36.

[0027] Mixed gas pipeline 26, mixed gas pipeline shut-off valve 27, mixed gas pipeline shut-off valve 28, mixed gas pipeline nitrogen purge pipeline 29, mixed gas pipeline nitrogen purge shut-off valve 30, mixed gas pipeline blind plate valve 31, mixed gas pipeline relief valve 32, mixed gas pipeline relief valve 33, mixed gas pipeline pressure gauge 34, mixed gas pipeline flowmeter 35,

[0028] The 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 mixed gas pipeline shut-off valve 27, the 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 mixed gas pipeline release valve 32 is installed on the mixed gas pipeline 26, between the mixed gas pipeline shut-off valve 27 and the mixed gas pipeline blind valve 31, the mixed gas pipeline release valve 33 is installed on the mixed gas pipeline 26, the mixed gas pipeline blind valve 31 and the mixed gas pipeline shut-off valve 28, a mixed gas pipeline pressure gauge 34 is installed on the mixed gas pipeline 26, a mixed gas pipeline cut-off valve 28 is located behind the mixed gas pipeline, a mixed gas pipeline flowmeter 35 is installed on the mixed gas pipeline 26, a mixed gas pipeline pressure gauge 34 is located behind the mixed gas pipeline flowmeter 35, a mixed gas pipeline purge nitrogen pipeline 29 is installed at a position behind 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 starting end 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 safety nitrogen shut-off valve 22 and a safety nitrogen shut-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 starting end 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 during a long-term air shutdown or to treat abnormal furnace conditions comprises the following steps:

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

[0034] The normal operating state of the hydrogen-rich carbon circulating oxygen blast furnace is the mixed gas supply mode of hot coal gas, cold oxygen, and safety nitrogen. Before the air is shut down for at least one smelting cycle, the hot coal gas and cold oxygen injection are stopped. Before the hot coal gas injection is stopped, the theoretical combustion temperature is controlled between 1900-2400℃ and the pressure reduction operation of reducing coal gas and oxygen is carried out. After the hot coal gas injection is stopped, the oxygen content of the whole air is controlled below 25% and the oxygen reduction operation is carried out until the oxygen is stopped. Process:

[0035] Pass the security nitrogen: open the security nitrogen regulating valve 44, open the security nitrogen cut-off valves 22 and 23, and control the security nitrogen flow to 5000m3 / 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 mixed gas pipeline shut-off valve 27, open the mixed gas pipeline nitrogen purge shut-off valve 30, purge for 1 minute, close the mixed gas pipeline shut-off valve 28, open the mixed gas pipeline bleed valve 32 and the mixed gas pipeline bleed valve 33, close the mixed gas pipeline nitrogen purge shut-off valve 30, and close the mixed gas pipeline blind plate valve 31.

[0037] Stop spraying cold oxygen 39.

[0038] Blowing hot compressed air: Confirm that the compressed air pipeline shut-off valve 2 and the compressed air pipeline shut-off valve 3 are closed, open the compressed air pipeline blind valve 4, close the compressed air pipeline release valve 5 and the compressed air pipeline release valve 6, open the compressed air pipeline shut-off valve 2 and the 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 hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline shut-off valve 13 are closed, open the hot oxygen pipeline blind valve 14, close the hot oxygen pipeline release valve 15 and the hot oxygen pipeline release valve 16, open the hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline shut-off valve 13, and regulate the hot oxygen flow 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 control the oxygen content of the total mixed air between 21% and 25% during this period. 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 taphole and block the other half of the tuyere far from the taphole before re-airing. Re-air half of the tuyere, and still select the air supply mode of hot compressed air, hot oxygen and hot nitrogen mixture during the re-airing process: first send security nitrogen to 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] Switch to air supply mode after S3 furnace condition is restored:

[0044] When the furnace condition gradually recovers, the furnace temperature tends to normal, the iron tapping tends to normal, the charge unloading is normal, 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 switched to the hot coal gas, hot oxygen, and security nitrogen mixed air supply mode. 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 hot oxygen pipeline shut-off valve 12 and the hot oxygen pipeline shut-off valve 13, open the hot oxygen pipeline bleed valve 15 and the hot oxygen pipeline bleed valve 16, close the hot oxygen pipeline nitrogen purge valve 18, and close the hot oxygen pipeline blind plate 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 compressed air pipeline shut-off valve 2 and the compressed air pipeline shut-off valve 3, open the compressed air pipeline bleed valve 5 and the compressed air pipeline bleed 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: cold oxygen 39 is introduced into the blast furnace tuyere, and the amount of injected cold oxygen is adjusted. During this period, the oxygen content of the total mixed gas is controlled between 21% and 25%. After 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.

[0048] Hot gas injection: Confirm that mixed gas pipeline shutoff valves 27 and 28 are closed. Open the mixed gas pipeline blind valve 31, open the mixed gas pipeline nitrogen purge shutoff valve 30, close the mixed gas pipeline bleed valve 32 and the mixed gas pipeline bleed valve 33, open the mixed gas pipeline shutoff valves 27 and 28, and adjust the mixed gas pipeline regulating valve 43, gradually increasing the mixed gas injection rate until it meets operational production requirements. When the mixed gas injection rate exceeds 5000 m3 / h, close the mixed gas pipeline nitrogen purge shutoff valve 30. Example

[0049] The following is an example of restoring the furnace condition using the above method, taking the HY blast furnace of Xinjiang Bagang's low-carbon test platform as the implementation object.

[0050] The scheduled maintenance of the HY blast furnace operating area of ​​the hydrogen-rich carbon cycle oxygen blast furnace (HRCBO) was completed at 11:15 AM on May 25, 2023. The main overhaul included partial replacement of the tuyere air supply mechanism, refabrication of the main trench, complete replacement of the mud gun, and replacement of the slag flushing duckbill. The maintenance lasted 1,575 minutes, from 9:00 AM on the 24th to 11:15 AM on the 25th.

[0051] The structure of blast furnace blast material on May 24 is as follows:

[0052] ;

[0053] Iron production during the smelting cycle before the shutdown on May 24:

[0054] ;

[0055] 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.

[0056] The blast furnace re-airing method adopts: nitrogen, cold oxygen, hot coal gas mixed gas injection re-airing method, the tuyere is fully open for air supply (14 tuyere), and the re-airing parameter setting is:

[0057] ;

[0058] After the blast furnace was blasted at 11:50 on the 25th, the iron tapping situation in front of the furnace was as follows:

[0059] ;

[0060] The blast furnace was opened at 11:50 on the 25th. At 12:18, the south probe reached 1.42 meters and the north probe reached 1.24 meters. The feed line remained inactive, indicating overburden in the blast furnace. The hot blast pressure was 155 kPa, with a pressure differential of 84 kPa. At 14:27, the furnace suddenly collapsed, and the south probe reached 1.42 meters and the north probe reached 1.24 meters, becoming 2.47 meters and 2.32 meters, respectively. The hot blast pressure was 117 kPa, with a pressure differential of 31 kPa.

[0061] 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 water flow trend of the small sets was checked and it was found that the 2#3#6# small sets 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 sets were leaking, and the 2#3#6# small sets were leaking. The wind was shut down at 20:05 on the 25th. A total of 26 batches of materials were added after the wind was resumed.

[0062] 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 wind-down period. A total of 31.67m³ of soft water was added during the wind-down period. 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 blast furnace charging system parameters were: ore batch weight: 14.5t, coke batch weight: 4.78t, coke ratio: 515.3Kg / t, load: 3.021, charging mode: 2P 24.5° 6 turns↓2K 24.5° 6 turns↓Charging line: 1.6m. The blast furnace restoration method adopted is the restoration method of nitrogen, cold oxygen, and hot coal gas mixture injection, with 11 tuyere air supply, and the restoration air supply parameter settings:

[0063] ;

[0064] After the restoration of air flow, the taphole was opened around 3:00 PM, and a small amount of red slag and iron erupted, followed by a large outflow, which then blocked the taphole. There were 11 tuyere vents, and tapholes 3, 4, and 5 were clogged with taphole mud. After the restoration of air flow, the tuyere operated normally, and the feed line moved slowly. At 3:07 PM on the 26th, the blast furnace began injecting coke oven gas. At 3:08 PM, a small pipe developed in the blast furnace, causing the top pressure to rise to 184 kPa and the top temperature to 135°C. Behind the pipe, the north probe (1.94 m) and south probe (2.24 m) suddenly increased to 4.08 m and 3.86 m, respectively. Abnormal inflow and outflow of water into and out of the tuyere sleeves (6#, 7#, 8#, 9#, and 11#) were discovered, and the liquid level in the blast furnace expansion tank dropped rapidly. A water inspector was notified to inspect the tuyere, and the tuyere was restored to black. On-site inspection revealed leaks in the small sleeves (6#, 7#, 8#, 9#, and 11#) and the large sleeve (6#). At 4:20 PM, the blast furnace was shut down to replace the damaged air supply device.

[0065] At the 8:18 AM morning meeting on the 27th, all positions jointly resolved to handle the incident as a furnace cooling event. During the day shift, oxygen firing was carried out on tuyeres 1# and 14# (replacing the 1#, 2#, 13#, and 14# small sleeves with double-cavity small sleeves), and oxygen lances were buried at the taphole. At 8:25 PM on the 27th, the blast furnace was reopened. The charging system parameters for this re-aired blast furnace were: ore batch weight: 12t, coke batch weight: 5.3t, coke ratio: 698 kg / t, load: 2.26, charging pattern: 2P 23.5° 6 turns ↓ 3K 23.5° 8 turns ↓ charging line: 1.6m.

[0066] The blast furnace re-airing method adopts: nitrogen, hot oxygen, hot compressed air mixed injection re-airing method, 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%. The re-airing parameter settings for this time are:

[0067] ;

[0068] At around 3:20 on the 28th, on-site inspection found that the front cavity of the 13# small sleeve was leaking. 7.5m³ of water was controlled 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 for iron tapping in front of the furnace, 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 supplied to the blast furnace tuyere. At around 19:00, decarbonized coal gas was supplied to the blast furnace. At around 23:00, coke oven gas was supplied to the blast furnace. At this point, the blast furnace cooling was basically completed, 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. The handling of this blast furnace accident 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 the furnace is in abnormal condition: The normal operating state of the hydrogen-rich carbon cycle oxygen blast furnace is the 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 security nitrogen cut-off valves (22, 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 mixed gas pipeline cut-off valve (27), open the mixed gas pipeline nitrogen purge cut-off valve (30), purge for 1 minute, close the mixed gas pipeline cut-off valve (28), open the mixed gas pipeline vent valve (32) and the 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); Stop spraying cold oxygen (39); Blowing hot compressed air: confirm that the compressed air pipeline shut-off valve (2) and the compressed air pipeline shut-off valve (3) are closed, open the compressed air pipeline blind valve (4), close the compressed air pipeline relief valve (5) and the compressed air pipeline relief valve (6), open the compressed air pipeline shut-off valve (2) and the 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 hot oxygen pipeline shut-off valve (12) and the hot oxygen pipeline shut-off valve (13) are closed, open the hot oxygen pipeline blind valve (14), close the hot oxygen pipeline vent valve (15) and the hot oxygen pipeline vent valve (16), open the hot oxygen pipeline shut-off valve (12) and the 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 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 will be 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, the air supply mode of hot compressed air, hot oxygen, and hot nitrogen mixture is still selected: first send security nitrogen, purge the system for 1 minute, and operate according to the sequence of S1 hot compressed air injection and hot oxygen injection 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; Switch the air supply mode after the S3 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, the hot compressed air, hot oxygen, and hot nitrogen mixed air supply mode is switched to the hot coal gas, hot oxygen, and security nitrogen mixed air supply mode. 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 is 0, close the hot oxygen pipeline shut-off valve (12) and the hot oxygen pipeline shut-off valve (13), open the hot oxygen pipeline vent valve (15) and the 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 compressed air pipeline shut-off valve (2) and the compressed air pipeline shut-off valve (3), open the compressed air pipeline vent valve (5) and the compressed air pipeline vent valve (6), close the compressed air pipeline nitrogen purge valve (8), and close the compressed air pipeline blind valve (4); Injecting cold oxygen: inject cold oxygen (39) into the blast furnace tuyere, and adjust the amount of injected cold oxygen. During this period, the oxygen content of the total mixed gas is controlled between 21% and 25%. When the amount of injected cold oxygen 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 mixed coal gas pipeline shut-off valve (27) and the mixed coal gas 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 mixed coal gas pipeline vent valve (32) and the mixed coal gas pipeline vent valve (33), open the mixed coal gas pipeline shut-off valve (27) and the mixed coal gas shut-off valve (28), adjust the mixed coal gas pipeline regulating valve (43), and gradually increase the mixed coal gas injection volume until it meets the production needs. 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. A method for supplying air to a hydrogen-rich carbon cycle oxygen blast furnace during long-term air stoppage, 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 the interlocking protection safety nitrogen pressure - compressed air pressure>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 the interlocking protection safety nitrogen pressure - hot oxygen pressure>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 the interlocking protection safety nitrogen pressure - mixed gas pressure>0.05MPa, otherwise the mixed gas regulating valve and cut-off valve will all be automatically interlocked and closed.

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