Blast furnace tuyere oxygen lance

Abstract

The utility model belongs to the field of blast furnace ironmaking, and particularly relates to a blast furnace tuyere oxygen injection technology. The blast furnace tuyere oxygen lance comprises an oxygen lance spray pipe and an oxygen lance head, and the oxygen lance spray pipe and the oxygen lance head are welded together. The oxygen lance head comprises a contraction section, a throat opening and an expansion section. The half cone angle of the contraction section is 10-30 degrees, and the half cone angle of the expansion section is 5-20 degrees. And the length ratio of the contraction section to the throat to the expansion section is (20-30%): (0-10%): (50-70%). The diameter d1 of the contraction section is larger than the diameter d0 of the throat opening and smaller than the diameter d2 of the expansion section. The blast furnace tuyere has the beneficial effects that the superspeed oxygen jet flow is added at the blast furnace tuyere, so that the depth of a convolution area is increased, dead stock columns are reduced, the updating speed of the dead stock columns is improved, the hearth works actively, the fuel consumption of the blast furnace is reduced, the molten iron circulation of the hearth is reduced, and the service life of the blast furnace is prolonged.

Description

Technical Field

[0001] The utility model belongs to the technical field of blast furnace ironmaking, and particularly relates to a blast furnace tuyere oxygen injection technology. Background Art

[0002] In the process of blast furnace ironmaking, iron ore and coke are added to the blast furnace in batches from the top of the furnace, and oxygen-enriched hot air is injected into the blast furnace from the tuyere. The oxygen-enriched hot air burns coke and pulverized coal in front of the tuyere, generating heat and CO-containing gas. The iron ore and coke move in the opposite direction to the CO-containing gas. During the downward movement, the iron ore is heated and reduced, and gradually melts to form slag and iron, thus completing the blast furnace ironmaking process. The blast furnace is successively divided into a burden zone, a softening-melting zone, a dripping zone, a combustion zone, and a slag-iron storage zone from top to bottom. Among them, the combustion zone is the area where coke and pulverized coal in front of the tuyere are burned and gasified by oxygen-enriched hot air. The combustion zone includes a tuyere raceway and a coke loosening zone in front of the raceway. The size of the tuyere raceway has an important impact on the production efficiency and quality of the blast furnace.

[0003] In modern intensified blast furnaces, oxygen-enriched hot air is injected into the blast furnace from the tuyere, forming a raceway with an approximately spherical space in front of the tuyere. The transition region between the raceway and the dead stock column is a coke loosening zone with a thickness of 200 - 300 mm. The dead stock column is a stationary coke bed existing in the blast furnace hearth. If the sediments in the dead stock column are not fully removed, the sediments will accumulate and reduce the gas permeability of this region.

[0004] The main factor affecting the size of the blast furnace raceway is the blast kinetic energy of the blast furnace, and the main factor affecting the blast kinetic energy is the blast velocity of the blast furnace. At present, the actual wind speed in blast furnace operation is only 200 - 260 m / s. Therefore, the blast kinetic energy of the blast furnace cannot be infinitely increased. Especially for large blast furnaces, due to the large hearth diameter, the center of the blast furnace cannot be blown through, the hearth of the blast furnace is inactive, and the gas permeability and liquid permeability of the dead stock column in the center of the blast furnace become poor.

[0005] Under normal blowing conditions, oxygen is quickly consumed after leaving the tuyere, and the oxygen distribution usually does not extend too far into the raceway. The combustion of the injected pulverized coal and fine residual coke sediments is insufficient, resulting in the deposition of carbon powder materials in the voids of the coke loosening zone between the raceway and the dead stock column, thereby reducing the gas permeability of this region, affecting the gas permeability and liquid permeability of the dead stock column in the blast furnace, and further preventing the gas from penetrating to the center of the blast furnace, affecting the initial distribution of the hearth gas, and also largely determining or influencing the secondary distribution of the gas flow in the blast furnace.

[0006] How to take effective measures to remove carbon deposits, improve the hearth gas permeability, and improve the gas flow distribution has become an urgent problem to be solved at present. Summary of the Invention

[0007] The purpose of the present utility model is to provide an oxygen lance for a blast furnace tuyere, which adds a high-speed oxygen jet in the tuyere to increase the depth of the recirculation zone, remove carbon deposits, and reduce the dead stock column.

[0008] The present utility model is achieved through the following technical solutions:

[0009] An oxygen lance is added to the blast furnace tuyere. The oxygen flow rate ejected by the lance is > 350 m / s. This oxygen jet eliminates the carbon powder material deposited in the voids of the transition zone between the recirculation zone and the "dead stock column", increases the depth of the recirculation zone, removes carbon deposits, and reduces the dead stock column.

[0010] An oxygen lance for a blast furnace tuyere includes an oxygen lance nozzle and an oxygen lance tip, which are welded together; the oxygen lance tip includes a contraction section, a throat, and a divergence section; the oxygen lance is inserted through the blast furnace blowing pipe, and the oxygen lance outlet is inside the tuyere.

[0011] Preferably, the half-cone angle of the contraction section is 10 - 30°, and the half-cone angle of the divergence section is 5 - 20°.

[0012] Preferably, the length ratio of the contraction section: throat: divergence section is 20 - 30%: 0 - 10%: 50 - 70%.

[0013] Preferably, the diameter d0 of the throat < the diameter d1 of the contraction section < the diameter d2 of the divergence section.

[0014] Preferably, the material of the oxygen lance is a high-temperature resistant material.

[0015] Preferably, the material of the oxygen lance is 310S.

[0016] Preferably, oxygen is blown into the blast furnace through the oxygen lance, and the oxygen flow rate at the throat reaches the speed of sound.

[0017] Preferably, the oxygen flow rate at the oxygen lance outlet is greater than the speed of sound, even several times the speed of sound.

[0018] The beneficial effects of the present utility model are as follows: By adding a super-high-speed oxygen jet in the blast furnace tuyere, the depth of the recirculation zone is increased, the dead stock column is reduced, the renewal speed of the dead stock column is improved, the furnace hearth works actively, the fuel consumption of the blast furnace is reduced, the molten iron circulation in the furnace hearth is reduced, and the service life of the blast furnace is improved. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the installation position of the oxygen lance

[0020] Figure 2 It is a schematic diagram of the oxygen lance for a blast furnace tuyere

[0021] Figure 3 It is a schematic diagram of the oxygen lance tip

[0022] Legend Mark

[0023] 1 Oxygen lance, 11 Oxygen lance barrel, 12 Oxygen lance tip, 121 Converging section, 122 Throat, 123 Diverging section, 2 Tuyere, 3 Blowing pipe, 4 Valve, 5 Check valve, 6 Oxygen supply device, 7 Oxygen distribution controller, 8 Nitrogen supply device. Specific Embodiment

[0024] Embodiment 1:

[0025] The following takes Figure 1 、 2 、3 as a reference to describe the implementation of the present invention in detail so that those of ordinary skill in the art can easily implement it. The present invention can be embodied in many different forms and is not limited to this description.

[0026] The oxygen lance 1 is connected to the check valve 5, the check valve 5 is connected to the blowing pipe 3, and the oxygen lance tip 12 of the oxygen lance 1 is inside the tuyere 2. The front end of the oxygen lance tip 12 is about 100 mm from the front end of the tuyere 2.

[0027] The oxygen lance tip 12 includes a diverging section 121, a throat 122, and a diverging section 123; the diameter d0 of the throat is 10 mm, the diameter d1 of the converging section is 20 mm, and the diameter d2 of the diverging section is 40 mm. The total length of the oxygen lance tip 12 is 80 mm, of which the converging section: 16 mm, the throat: 4 mm, and the diverging section 60 mm. The oxygen lance is made of 310S.

[0028] The included angle between the center line of the oxygen lance 1 and the center line of the tuyere 2 is 0 - 10°.

[0029] The oxygen from the oxygen supply device 6 is sent to the oxygen distribution controller 7. The outlet branch of the oxygen distribution controller 7 corresponds to the number of blast furnace tuyeres. The oxygen coming out of the oxygen distribution controller 7 is sent to the oxygen lance 1 through the valve 4. The oxygen passes through the oxygen lance barrel 11 of the oxygen lance 1 and is accelerated by the converging section 121 of the oxygen lance tip 12. When it reaches the throat 122, the oxygen velocity is greater than 350 m / s, and it is further accelerated by the diverging section 123. Then the oxygen is blown into the blast furnace at an extremely high speed. The high-speed oxygen shock wave can reach the deep part of the tuyere recirculation zone to burn the pulverized coke, enabling the oxygen to reach the area that the oxygen-enriched hot blast cannot reach during the normal blast furnace blowing process. This part of the oxygen reacts with the carbon powder at the rear of the recirculation zone and enters the transition zone outside the recirculation zone, eliminating the carbon powder material deposited in the voids of the transition zone between the recirculation zone and the "dead stock column", reducing the dead stock column and improving the permeability of the hearth.

[0030] The nitrogen supply device 8 serves as the security gas source of the system. When the oxygen supply pressure of the oxygen supply device 6 is low, the outlet valve of the nitrogen supply device 8 is opened to supply nitrogen.

[0031] The implementation of this technical solution can achieve an increase in the utilization of blast furnace gas by more than 1%, a reduction in the fuel ratio by 2%, an increase in the coal ratio by 10%, and can also extend the service life of the blast furnace.

[0032] Embodiment 2

[0033] The difference from Embodiment 1 is that the valve 4 is periodically switched on and off rapidly to inject intermittent high-speed oxygen impact jets into the furnace.

[0034] The oxygen lance 1 enters from the rear end of the tuyere 2, and the tip 12 of the oxygen lance comes out from the inner cavity side wall of the tuyere 2.

[0035] The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and variations based on the concept of the present invention without creative efforts. Therefore, all technical solutions that can be obtained by those skilled in the art in this technical field based on the concept of the present invention through logical analysis, reasoning, or limited experiments on the basis of the prior art shall fall within the protection scope determined by the claims.

Claims

1. A blast furnace tuyere oxygen lance, characterized in that, It includes an oxygen lance nozzle and an oxygen lance tip, and the oxygen lance nozzle and the oxygen lance tip are welded together; the said oxygen lance tip includes a contraction section, a throat and an expansion section; the said oxygen lance is inserted through the tuyere blowing pipe of the blast furnace, and the oxygen lance outlet is inside the tuyere.

2. The oxygen lance for blast furnace tuyere according to claim 1, wherein, The half-cone angle of the contraction section is 10 - 30°, and the half-cone angle of the expansion section is 5 - 20°.

3. The oxygen lance for blast furnace tuyere according to claim 1, characterized in that, The length ratio of the contraction section : the throat : the expansion section is 20 - 30% : 0 - 10% : 50 - 70%.

4. The oxygen lance for blast furnace tuyere according to claim 1, characterized in that, The diameter d0 of the throat < the diameter d1 of the contraction section < the diameter d2 of the expansion section.

5. The oxygen lance for blast furnace tuyere according to claim 1, characterized in that, The material of the oxygen lance is a high-temperature resistant material.

6. The oxygen lance for blast furnace tuyere according to claim 5, characterized in that, The material of the oxygen lance is 310S.

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