A hydrogen-rich blast furnace tuyere small sleeve and a control method thereof

Abstract

The application discloses a blast furnace hydrogen-rich tuyere small sleeve and a control method thereof, and relates to the technical field of blast furnaces, in particular to a blast furnace hydrogen-rich tuyere small sleeve and a control method thereof. The blast furnace hydrogen-rich tuyere small sleeve comprises a copper alloy base body, the copper alloy base body has a front end extending into a blast furnace and a rear end connected with a blast furnace air supply pipeline, an airflow channel is formed in the copper alloy base body and extends through the front end and the rear end, a circulating water cooling channel is arranged in the wall body of the copper alloy base body, the rear end of the copper alloy base body is provided with a hydrogen-rich inlet, a cooling water inlet and a cooling water outlet which are in communication with the circulating water cooling channel, the front end of the copper alloy base body is provided with an end face, and the inside of the copper alloy base body is further provided with a hydrogen-rich outlet which is in communication with the hydrogen-rich inlet. The blast furnace hydrogen-rich tuyere small sleeve has the advantages that through structural optimization and matched process cooperation, the service life of the blast furnace hydrogen-rich tuyere small sleeve is increased from about 60 days to the level of 120 days close to that of a conventional tuyere.

Description

Technical Field

[0001] This invention relates to the field of blast furnace ironmaking air supply equipment and process technology, and in particular to a small jacket for a hydrogen-rich tuyere in a blast furnace and its control method. Background Technology

[0002] The tuyere sleeve is a core component of the blast furnace air supply system, undertaking the crucial task of delivering high-temperature hot air, pulverized coal, and auxiliary injection media into the furnace. Traditional tuyere sleeves are mainly made of copper alloy and achieve high-temperature protection through internal circulating water cooling. Under conventional blast furnace production conditions, their service life can generally reach about 120 days. The technology is mature and can meet the needs of conventional smelting.

[0003] With the development of low-carbon blast furnace smelting technology, hydrogen-rich (coke oven gas) injection technology has been gradually promoted, aiming to reduce coke consumption and carbon emissions by injecting hydrogen-containing media into the tuyere. However, this technology poses new challenges to the operation of the tuyere jacket. The structure and design of traditional tuyere jackets cannot adapt to the special operating conditions brought about by hydrogen-rich injection, becoming a key bottleneck restricting the stable application of hydrogen-rich technology.

[0004] Defects and shortcomings of existing technology: Insufficient adaptability to operating conditions and significantly shortened service life: The structural design of traditional tuyere sleeves does not consider the special operating conditions of hydrogen-rich injection. Under hydrogen-rich injection conditions, the approximately 50mm area at the front end face of the tuyere sleeve outlet is constantly exposed to a complex thermochemical and physical erosion environment. The service life of a conventional tuyere sleeve is about 120 days, while that of a hydrogen-rich tuyere sleeve is only about 60 days, a reduction of half the service life. This significantly increases equipment replacement costs and blast furnace downtime rates, affecting production continuity.

[0005] Endothermic reactions cause localized temperature fluctuations, exacerbating coking and adhesion: During hydrogen-rich injection, both the low-temperature hydrogen and the injected pulverized coal undergo endothermic reactions in the tuyeres area, resulting in a sudden drop in localized temperature at the tuyeres. This causes frequent coking and adhesion of the pulverized coal to the front end face of the small sleeve outlet. This periodic coking and detachment continuously erodes and impacts the front end of the small sleeve outlet, leading to a gradual deterioration of the localized toughness and strength of the copper alloy matrix.

[0006] The combined effect of hydrogen-rich medium scouring and corrosion accelerates failure and wear: On the one hand, the high-speed injection of hydrogen-rich medium creates a continuous airflow scouring the front end of the tuyeres sleeve, causing material wear; on the other hand, the coupling effect of coking, high temperature, and hydrogen medium further reduces the fatigue and corrosion resistance of copper alloy materials. Under the combined effect of multiple factors, the front end of the tuyeres sleeve is prone to localized burning and cracking, ultimately leading to the burning and wear of the cooling system, forcing a shutdown and replacement, directly affecting blast furnace production and causing significant economic losses. Summary of the Invention

[0007] The purpose of this invention is to provide a small jacket for hydrogen-rich tuyere in blast furnace and its control method. Through structural optimization and coordinated process, the service life of the small jacket for hydrogen-rich tuyere is increased from about 60 days to nearly 120 days for conventional tuyeres.

[0008] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A small jacket for hydrogen-rich tuyeres in a blast furnace includes a copper alloy substrate. The copper alloy substrate has a front end extending into the blast furnace and a rear end connected to the blast furnace air supply pipe. An airflow channel is formed within the copper alloy substrate, connecting the front and rear ends. A circulating water cooling channel is provided within the wall of the copper alloy substrate. The rear end of the copper alloy substrate has a hydrogen-rich inlet and a cooling water inlet and outlet connected to the circulating water cooling channel. The front end of the copper alloy substrate has an end face, and a hydrogen-rich outlet connected to the hydrogen-rich inlet is also provided inside the copper alloy substrate.

[0009] Preferably, a fire-resistant and corrosion-resistant composite coating is provided on the inner circumferential area of ​​the airflow channel extending inward from the front end face of the copper alloy substrate to 300mm, with the hydrogen-rich outlet centerline as the reference.

[0010] Preferably, the fire-resistant and corrosion-resistant composite coating is applied to the inner wall of the airflow channel by spraying. The fire-resistant and corrosion-resistant composite coating is a ceramic-based composite coating or a metal-based composite coating, and the thickness of the fire-resistant and corrosion-resistant composite coating is 2.5 mm.

[0011] Preferably, the angle between the centerline of the hydrogen-rich outlet and the centerline of the copper alloy substrate is 35°.

[0012] Preferably, the hydrogen-rich outlet is located at the front end of the copper alloy substrate and extends obliquely towards the airflow channel, with the center line of the hydrogen-rich outlet being 250 mm from the front end face of the copper alloy substrate.

[0013] Preferably, the cooling water inlet and cooling water outlet are evenly distributed along the circumferential direction of the rear end face of the copper alloy substrate, and the cooling water inlet, cooling water outlet and hydrogen-rich inlet are all inclined at 10°.

[0014] Preferably, the circulating water cooling channel is an annular water cavity formed within the wall of the copper alloy substrate, and the annular water cavity is arranged around the airflow channel.

[0015] A control method for a small jacket of a hydrogen-rich tuyere in a blast furnace, comprising the following steps: The hydrogen-rich injection pressure is controlled at 1.5 times the hot air pressure; When localized slag shedding is discovered at the tuyeres during blast furnace control or on-site inspections, nitrogen purging should be initiated immediately, and hydrogen-rich injection should be stopped simultaneously. When coking occurs at the hydrogen-rich tuyer, immediately stop coal injection and open the nitrogen purging valve for purging. After the coke has completely fallen off and the tuyeres have returned to normal, the normal injection of pulverized coal and coke oven gas will be resumed in sequence.

[0016] Preferably, when local slag shedding is found at the tuyeres during blast furnace central control or on-site inspection, the nitrogen pressure for nitrogen purging is controlled to be 1.0 to 1.5 times the hot blast pressure.

[0017] Preferably, when coking occurs at the hydrogen-rich tuyer, coal injection should be stopped immediately, and the nitrogen purging valve should be opened for purging. If the coking does not fall off within 1 minute, coke oven gas injection should be stopped until the coking is completely removed.

[0018] In summary, the beneficial effects of this invention are that it can effectively solve the problems of easy coking, easy erosion and wear, and short service life of the tuyer sleeve under hydrogen-rich injection conditions, increasing the service life of the hydrogen-rich tuyer sleeve from about 60 days to nearly 120 days of conventional tuyer sleeves, while reducing the risk of tuyer leakage and shutdown, and ensuring the long-term stable operation of the hydrogen-rich blast furnace process. Attached Figure Description

[0019] Figure 1 This is a structural diagram of one side of the rear end of the small sleeve for hydrogen-rich tuyeres in blast furnaces according to the present invention; Figure 2 yes Figure 1 Cross-sectional view along the hydrogen-rich inlet side; Wherein: 1-copper alloy substrate, 2-hydrogen-rich inlet, 3-hydrogen-rich outlet, 4-airflow channel, 5-fire-resistant and corrosion-resistant composite coating, 6-circulating water cooling channel, 7-cooling water inlet, 8-cooling water outlet. Detailed Implementation

[0020] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. These embodiments do not constitute a limitation on the present invention.

[0021] like Figure 1 and 2 The illustrated blast furnace hydrogen-rich tuyeres include a copper alloy substrate 1. The copper alloy substrate 1 has a front end extending into the blast furnace and a rear end connected to the blast furnace air supply pipe. An airflow channel 4 is formed inside the copper alloy substrate 1, connecting the front end and the rear end. A circulating water cooling channel 6 is provided inside the wall of the copper alloy substrate 1. The rear end of the copper alloy substrate 1 is provided with a hydrogen-rich inlet 2 and a cooling water inlet 7 and a cooling water outlet 8 connected to the circulating water cooling channel 6. The front end of the copper alloy substrate 1 is provided with an end face. A hydrogen-rich outlet 3 connected to the hydrogen-rich inlet 2 is also provided inside the copper alloy substrate 1.

[0022] Based on the centerline of the hydrogen-rich outlet 3, a fire-resistant and corrosion-resistant composite coating 5 is provided on the inner circumferential area of ​​the airflow channel 4 extending inward from the front end face of the copper alloy substrate 1 to 300mm. This area completely covers the coal powder coking area and high-temperature corrosion area during hydrogen-rich injection, achieving full coverage protection for key parts.

[0023] The fire-resistant and corrosion-resistant composite coating 5 is applied to the inner wall of the airflow channel 4 by spraying. The fire-resistant and corrosion-resistant composite coating 5 is either a ceramic-based composite coating or a metal-based composite coating, with a thickness of 2.5 mm. This thickness ensures the coating's resistance to corrosion and erosion without affecting the heat transfer efficiency of the air outlet due to excessive thickness, and also avoids excessive changes in the cross-sectional area of ​​the airflow channel 4. The coating material can be a high-temperature resistant, coking-resistant ceramic-based or metal-based composite coating, which can effectively isolate the coking at the air outlet from direct contact with the copper alloy substrate 1, avoiding the degradation of the substrate's toughness and strength caused by coking adhesion and repeated erosion, and significantly reducing the risk of the substrate being burned or corroded.

[0024] The angle between the centerline of the hydrogen-rich outlet 3 and the centerline of the copper alloy substrate 1 is 35°. This changes the jet trajectory of the hydrogen-rich gas, causing the gas to deflect towards the center of the furnace after it is ejected, reducing the direct contact between the gas and the inner wall of the tuyeres. The original angle was 30°. At this angle, the hydrogen-rich gas is prone to direct friction and scouring with the inner wall of the tuyeres after it is ejected. Long-term high-speed gas flow scouring will cause wear on the inner wall and aggravate local burn-out. The adjusted angle can effectively avoid direct friction and scouring between the hydrogen-rich gas and the inner wall of the tuyeres, reduce the physical wear of the inner wall by the high-speed gas flow, reduce the concentration of local heat load, thereby reducing the probability of the inner wall being scourted and worn, and local overheating and burn-out, and extending the service life of the tuyeres sleeve.

[0025] The hydrogen-rich outlet 3 is located at the front end of the copper alloy substrate 1 and extends obliquely towards the airflow channel 4. The center line of the hydrogen-rich outlet 3 is 250 mm away from the front end face of the copper alloy substrate 1.

[0026] Cooling water inlet 7 and cooling water outlet 8 are evenly distributed along the circumferential direction of the rear end face of the copper alloy substrate 1. Cooling water inlet 7, cooling water outlet 8 and hydrogen-rich inlet 2 are all inclined at 10°.

[0027] The circulating water cooling channel 6 is an annular water cavity opened in the wall of the copper alloy substrate 1, and the annular water cavity surrounds the airflow channel 4.

[0028] A method for controlling the small sleeve of a hydrogen-rich tuyere in a blast furnace includes the following steps: The hydrogen-rich injection pressure is controlled at 1.5 times the hot blast pressure. For example, when the hot blast pressure is 0.4 MPa, the hydrogen-rich injection pressure is controlled at 0.6 MPa. This pressure ensures that the hydrogen-rich medium can penetrate the pulverized coal flow at the front end of the tuyeres and be transported to the central area of ​​the blast furnace to achieve a full reduction reaction. At the same time, it avoids the severe scouring of the front end of the tuyeres by the airflow caused by excessive pressure, reducing local heat load and wear, and reducing the risk of damage to the front end of the tuyeres.

[0029] When slag shedding is detected in the tuyeres during blast furnace control or on-site inspections, nitrogen purging should be initiated immediately. The nitrogen pressure during purging should be controlled at 1.0 to 1.5 times the hot blast pressure, while hydrogen-rich injection should be stopped simultaneously. Nitrogen purging can rapidly cool the tuyeres area and blow away the detached slag and coal dust, preventing the slag from coupling with the hydrogen-rich airflow and adhering to the tuyeres surface, thus aggravating local damage. Stopping hydrogen-rich injection can eliminate the continuous impact of airflow scouring on the damaged areas, ensuring tuyeres safety and buying time for subsequent inspection and treatment.

[0030] When coking occurs at the hydrogen-rich tuyere, immediately stop coal injection and open the nitrogen purging valve to purge. Stopping coal injection can cut off the coal powder source and prevent coking from expanding further. Nitrogen purging can loosen and remove the coking through airflow impact and cooling, preventing the coking from continuing to adhere to the front end of the tuyere.

[0031] If the coke does not detach within 1 minute, stop the coking gas injection until the coke is completely detached. Stopping the coking gas injection can eliminate the continuous heat absorption and local temperature fluctuations in the coking area, reduce the bonding strength between the coke and the matrix, and prevent the coking gas from accumulating in the coking area, thus avoiding safety risks.

[0032] After the coke has completely fallen off and the tuyeres have returned to normal, the normal injection of pulverized coal and coke oven gas should be resumed in sequence. During the restoration process, the flow rate should be adjusted slowly to avoid sudden changes in operating conditions that could cause new coking.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within the scope of its essence and protection. Such modifications or equivalent substitutions should also be considered to fall within the protection scope of the present invention.

Claims

1. A small sleeve for a hydrogen-rich tuyere in a blast furnace, characterized in that, The invention includes a copper alloy matrix, which has a front end extending into the blast furnace and a rear end connected to the blast furnace air supply pipe. An airflow channel is formed within the copper alloy matrix, connecting the front and rear ends. A circulating water cooling channel is provided within the wall of the copper alloy matrix. The rear end of the copper alloy matrix has a hydrogen-rich inlet and a cooling water inlet and outlet connected to the circulating water cooling channel. The front end of the copper alloy matrix has an end face, and the interior of the copper alloy matrix also has a hydrogen-rich outlet connected to the hydrogen-rich inlet.

2. The small sleeve for a hydrogen-rich tuyeres in a blast furnace according to claim 1, characterized in that, With the hydrogen-rich outlet centerline as a reference, a fire-resistant and corrosion-resistant composite coating is provided on the inner circumferential area of ​​the airflow channel extending inward from the front end face of the copper alloy substrate to a depth of 300mm.

3. A small sleeve for a hydrogen-rich tuyere in a blast furnace according to claim 2, characterized in that, The fire-resistant and corrosion-resistant composite coating is applied to the inner wall of the airflow channel by spraying. The fire-resistant and corrosion-resistant composite coating is a ceramic-based composite coating or a metal-based composite coating, and the thickness of the fire-resistant and corrosion-resistant composite coating is 2.5 mm.

4. The small sleeve for a hydrogen-rich tuyere in a blast furnace according to claim 1, characterized in that, The angle between the centerline of the hydrogen-rich outlet and the centerline of the copper alloy substrate is 35°.

5. A small sleeve for a hydrogen-rich tuyere in a blast furnace according to claim 1, characterized in that, The hydrogen-rich outlet is located at the front end of the copper alloy substrate and extends obliquely towards the airflow channel. The center line of the hydrogen-rich outlet is 250 mm away from the front end face of the copper alloy substrate.

6. A small sleeve for a hydrogen-rich tuyere in a blast furnace according to claim 1, characterized in that, The cooling water inlet and cooling water outlet are evenly distributed along the circumferential direction of the rear end face of the copper alloy substrate, and the cooling water inlet, cooling water outlet and hydrogen-rich inlet are all inclined at 10°.

7. A small sleeve for a hydrogen-rich tuyere in a blast furnace according to claim 1, characterized in that, The circulating water cooling channel is an annular water cavity formed within the wall of the copper alloy substrate, and the annular water cavity surrounds the airflow channel.

8. A method for controlling the small jacket of a hydrogen-rich tuyere in a blast furnace, used to control the small jacket of a hydrogen-rich tuyere in a blast furnace as described in any one of claims 1 to 7, characterized in that, Includes the following steps: The hydrogen-rich injection pressure is controlled at 1.5 times the hot air pressure; When localized slag shedding is discovered at the tuyeres during blast furnace control or on-site inspections, nitrogen purging should be initiated immediately, and hydrogen-rich injection should be stopped simultaneously. When coking occurs at the hydrogen-rich tuyer, immediately stop coal injection and open the nitrogen purging valve for purging. After the coke has completely fallen off and the tuyeres have returned to normal, the normal injection of pulverized coal and coke oven gas will be resumed in sequence.

9. The control method for a small sleeve at a hydrogen-rich tuyere in a blast furnace according to claim 8, characterized in that, When slag shedding is found in some areas of the tuyeres during blast furnace central control or on-site inspection, the nitrogen pressure for nitrogen purging should be controlled to be 1.0 to 1.5 times the hot blast pressure.

10. The control method for a small sleeve at a hydrogen-rich tuyere in a blast furnace according to claim 8, characterized in that, When coking occurs at the hydrogen-rich tuyer, immediately stop coal injection and open the nitrogen purging valve. If the coking does not fall off within 1 minute, stop coke oven gas injection until the coking is completely removed.

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