KR20020078440A - Lance for injecting pulverized coal - Google Patents

Abstract

PURPOSE: A pulverized coal injection lance is provided which is not bended by dead load even at a high temperature by forming expansion transformation members on upper and lower parts of the outer circumferential surface of an inner tube of the pulverized coal injection lance consisting of a dual pipe. CONSTITUTION: In a pulverized coal injection lance which is consisting of a dual pipe of an outer tube and an inner tube in a hollow blow pipe positioned at tuyere inside a blast furnace to inject pulverized coal into the blast furnace, the pulverized coal injection lance comprises a first expansion transformation member(14) which is mounted on the upper part of the outer circumferential surface(12) of the inner tube(10) arranged in the blow pipe and has a low thermal expansion coefficient compared to the inner tube(10); and a second expansion transformation member(16) which is mounted on the lower part of the outer circumferential surface(12) of the inner tube(10) arranged in the blow pipe and has a high thermal expansion coefficient compared to the inner tube(10), wherein the pulverized coal injection lance is not bended by dead load in a high temperature atmosphere by using difference of thermal expansion coefficient between the first and second expansion transformation member(14,16) and the inner tube(10).

Description

Pulverized coal injection lance {LANCE FOR INJECTING PULVERIZED COAL}

The present invention relates to a pulverized coal blowing lance installed in a blast furnace in a steelworks blast furnace to supply pulverized coal during high temperature hot air, and more specifically, to form an expansion deformation member on the upper and lower outer peripheral surfaces of the inner tube of the pulverized coal blowing lance composed of a double pipe. The present invention relates to a pulverized coal injection lance that is not bent by its own weight.

In general, the conventional pulverized coal blowing operation is to increase the oxygen concentration blown into the tuyere by the oxygen enrichment operation so as to completely burn the pulverized coal 80 injected. To this end, as shown in FIG. 1, a pulverized coal injection lance 100 composed of a double pipe is inserted into a blow pipe 60 located at a tuyere 59 in the blast furnace 70, so that the inside of the pulverized coal injection lance 100 is inserted. The pulverized coal 80 is transferred to the tube 10, and oxygen and air are supplied to the passage between the inner tube 10 and the outer tube 20. The oxygen and air are used as a reaction gas for burning the pulverized coal 80 and also used as a coolant for cooling the pulverized coal injection lance 100.

In order to sufficiently cool the pulverized coal injection lance 100, oxygen should be smoothly supplied. However, when the blowing is stopped due to a sudden trouble of the pulverized coal manufacturing equipment or the individual blowing is stopped by the characteristics of each branch pipe, oxygen for cooling the pulverized coal injection lance 100 is not smoothly supplied, so the pulverized coal injection lance 100 Lack of cooling).

In addition, when the oxygen check valve 65 is broken or the oxygen transport port is blocked due to the backflow of the pulverized coal 80, oxygen is not sufficiently supplied through the outer tube of the pulverized coal injection lance 100 so that the cooling operation is not smoothly performed. do.

Accordingly, as shown in FIGS. 2 and 3, the pulverized coal blown lance 100 enters the hollow 62 in the pipe 60 from outside the blow pipe 60 under a hot air of about 1200 ° C. The part 55 is bent downward due to the softening action caused by the high temperature and the self-weight of the part 57 disposed in the hollow 62 of the inner tube to be struck down and thus injected from the pulverized coal injection lance 100. The pulverized coal 80 collides directly with the tuyere 59, causing local wear of the tuyere 59, and eventually causing a major accident in which the tuyere 59 is broken.

In addition, the inner tube 10 may be attached to the outer tube 20 by the bending of the pulverized coal injection lance 100. When the inner tube 10 is attached to the outer tube 20, the inner tube 10 and the outer tube 20 are stuck to oxygen even though the inner tube 10 is not restored to its original state and oxygen is supplied again to perform the cooling operation. Since the supply of is stopped, the cooling effect by oxygen cannot be expected.

In order to prevent such an accident, the pulverized coal injection lance 100 is monitored by the naked eye at regular intervals to monitor whether it is bent, but the state until the pulverized coal injection lance 100 is bent to the naked eye is confirmed. Cannot be determined in advance. In addition, in order to prevent breakage of the tuyere 59 due to the warpage of the pulverized coal injection lance 100, the injection of the pulverized coal 80 is stopped, and the pulverized coal injection lance 100 is replaced at regular repair work and then operated again. Therefore, there is a problem that the operation loss occurs until the replacement of the pulverized coal injection lance (100).

The present invention is to solve the above conventional problems, by preventing the pulverized coal blown lance is prevented from being bent down by the softening action and its own weight in a high-temperature atmosphere, to prevent breakage of the tuyere and to always be able to operate The purpose is to provide a blown lance.

It is also an object of the present invention to provide a pulverized coal blowing lance to improve combustion efficiency by smooth mixing of pulverized coal and oxygen.

1 is a perspective view showing a conventional pulverized coal injection flow as a whole

Figure 2 is a perspective view showing that the conventional pulverized coal injection lance is deformed by the heat load

3 is a sectional view showing a circumferential cross section of a portion where the pulverized coal injection lance enters into the hollow in the blow pipe

4 is a sectional view showing a longitudinal section of a conventional pulverized coal injection lance;

5 is a perspective view of a pulverized coal injection lance according to the present invention;

6 is a cross-sectional view of the pulverized coal blown lance showing a cross section taken along the line A-A of FIG.

7 is a cross-sectional view of the pulverized coal blown lance showing a cross section taken along the line B-B of FIG.

8 is a cross-sectional view showing a longitudinal section of the pulverized coal injection lance according to the present invention.

Explanation of symbols on the main parts of the drawings

10 ... inner tube 20 ... outer tube

12 ... outer circumference 60 ... blow pipe

14 ... first expansion-deformation member 80 ... pulverized coal

16 ... second expansion deformation member 100 ... pulverized coal injection lance

As a technical configuration for achieving the above object, the present invention, in the pulverized coal injection lance is composed of a double pipe of the outer tube and the inner tube in the blow pipe located in the blast furnace inside the blast furnace to blow the pulverized coal into the blast furnace,

A first expansion-deformation member mounted on an inner circumferential surface 12 of the inner pipe 10 disposed in the hollow of the blow pipe and having a coefficient of thermal expansion smaller than that of the inner pipe; And a second expansion and deformation member having a coefficient of thermal expansion greater than that of the inner tube and mounted below the inner tube outer circumferential surface disposed in the hollow of the blow pipe, wherein the first and second expansion deformation members and the thermal expansion of the inner tube are included. By using the difference is to provide a pulverized coal blown lance characterized in that it is not bent by the weight in the high temperature atmosphere.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

The pulverized coal injection lance 100 according to the present invention is as shown in FIGS. 5 to 8.

The pulverized coal injection lance 100 according to the present invention includes an outer circumferential surface of a portion 57 (hereinafter, referred to as a hollow arrangement 57) of the inner pipe 10 disposed in the hollow 62 of the blow pipe 60. 12) The first expansion-deformation member 14 having a coefficient of thermal expansion smaller than the inner tube 10 is mounted on the upper portion, and larger than the inner tube 10 below the outer circumferential surface 12 of the hollow arrangement 57. A second expansion deformation member 16 having a thermal expansion coefficient is mounted.

The first expansion-deformation member 14 and the second expansion-deformation member 16 is mounted on the upper and lower portions of the outer circumferential surface 12 of the hollow arrangement 57, respectively, the pulverized coal injection lance 100 is It depends on the circumferential position located within the blow pipe 60.

As shown in FIG. 2, the pulverized coal injection lance 100 enters into the hollow 62 from the outside of the blow pipe 60, and as illustrated in FIG. 3, an inner upper portion of the blow pipe 60, That is, the blow pipe 60 enters the hollow 62 from the outside of the blow pipe 60 at a reference angle of 0 ° to 180 ° of the circumferential end surface of the blow pipe 60. If the pulverized coal injection lance 100 enters the hollow 62 of the blow pipe 60 at a circumferential angle of 130 °, the pulverized coal injection lance 100 is hollow 62 of the blow pipe 60. The portion 55 (hereinafter referred to as entry portion 55) that enters the inside is bent in the circumferential angle 300 ° direction by the softening action of the high temperature in the high temperature atmosphere and the weight of the hollow arrangement 57.

If the pulverized coal injection lance 100 enters into the hollow 62 of the blow pipe 60 in a circumferential angle of 90 °, the pulverized coal injection lance 100 is in a downward direction, that is, a circumferential angle of 270 ° in a high temperature atmosphere. Will be bent in the direction.

Since the direction in which the pulverized coal injection lance 100 enters into the hollow 62 of the blow pipe 60 is changed in a bending direction, the first expansion deformation member 14 and the second expansion deformation member 16 are different. The pulverized coal injection lance 100 is preferably mounted on the upper and lower portions of the inner tube 10 in a bending direction.

For example, if the pulverized coal injection lance 100 enters into the hollow 62 of the blow pipe 60 as in FIG. 3, the first expansion-deformation member 14 may be formed in the inner tube (FIG. 5 and 6). 10) Preferably, it is mounted near about 130 ° of the outer circumferential surface and the second expandable deformable member 16 is mounted near about 300 ° of the inner tube 10.

As another example, if the pulverized coal injection lance 100 enters into the hollow 62 of the blow pipe 60 near 90 °, the first expansion-deformation member 14 is about about the outer circumferential surface of the inner tube 10. Preferably, it is mounted near 90 degrees and the second expanding deformation member 16 is mounted near about 270 degrees of the inner tube 10.

The bending force is increased in the opposite direction to the direction in which the pulverized coal injection lance 100 is bent under high temperature by using the thermal expansion difference between the first expansion deformation member 14 and the second expansion deformation member 16 and the inner tube 10. To work.

As described above, the first expansion-deformation member 14 mounted on the inner circumferential surface 12 of the inner tube 10 is selected as a member having a coefficient of thermal expansion smaller than that of the inner tube 10 and the lower outer circumferential surface of the inner tube 10. The second expansion-deformation member 16 mounted to is selected as a member having a coefficient of thermal expansion larger than that of the inner tube 10.

Various metal materials and alloy materials may be selected for the first expansion deformation member 14 and the second expansion deformation member 16, and the coating layer having a coefficient of thermal expansion desired by mixing various materials may be provided in the inner tube 10. It can be formed on the outer peripheral surface 12.

In the embodiment according to the present invention, when the material of the inner tube 10 is selected as SUS310, various materials are mixed as the first expansion-deformation member 14 to have heat resistance having a coefficient of thermal expansion smaller than that of the inner tube 10. An alloy powder was selected and sprayed with argon or hydrogen plasma on the inner peripheral surface of the inner tube 10 to form a coating layer. As the second expansion deformation member 16, a metal plate made of copper (Cu) material having a thermal expansion coefficient larger than that of the inner tube 10 was selected and formed below the outer peripheral surface of the inner tube 10.

Of course, a metal plate having a thermal expansion coefficient smaller than that of the inner tube 10 may be selected as the first expansion deformation member 14, and a thermal expansion coefficient larger than the inner tube 10 with the second expansion deformation member 16. By selecting the heat-resistant alloy-based coating layer may be formed on the lower inner tube (10).

The coefficient of thermal expansion of SUS310 selected as the inner tube 10 is 16.2x10-6 / ° C near 316 ° C, 16.9x10-6 / ° C near 538 ° C, and 17.5x10-6 / ° C near 650 ° C and the second expansion The coefficient of thermal expansion of copper (Cu) selected as the deformable member 16 is 17.3x10 < -6 > / deg. C at 316 deg. C, 18.3x10 < -6 > The heat-resistant alloy coating layer, which is the first expansion deformation member, has a coefficient of thermal expansion smaller than SUS310 at temperatures of 316 ° C, 538 ° C, and 650 ° C, respectively, and Ni42.2%, Cr14.2%, Al29.7%, Co0.8. %, ZrO2 1.2%, and other heat-resistant alloy powder having a composition of Fe and impurities.

The first expansion deformation member 14 and the second expansion deformation member 16 each have a groove sized by the sizes of the first and second expansion deformation members 14 and 16 on the upper and lower peripheral surfaces of the inner tube 10. After forming, it may be mounted in the groove. The inside of the first groove 15 for mounting the coating layer, which is the first expanded deformation member 14, is subjected to ultrasonic cleaning using acetone and the second groove for mounting the copper plate, which is the second expanded deformation member 16. The inside of the 17 and the inner surface of the copper plate are smoothly processed to be in close contact with each other.

After the grooves 15 and 17 are formed on the outer circumferential surface 12 of the inner tube 10, the first and second expansion-deformation members 14 and 1 6 are mounted on the grooves. In order to increase the expansion effect of the two expansion deformation members (14, 16), and for another reason, the first and second expansion deformation members (14) and (16) can be combined with various coupling means without forming the groove. 29) is to reduce the occurrence of defects such as cracks generated in the coupling means 29 during thermal expansion than when formed on the outer peripheral surface of the inner tube (10) by (for example, welding). If cracks are generated in the coupling means 29 such as a weld as described above, the effect due to the difference in thermal expansion between the first and second expansion deformation members 14 and 16 and the inner tube 10 may be greatly reduced.

Unlike the first expansion deformation member 14, a protrusion 13 is formed in the center of the second expansion deformation member 16 in an outward direction, and a groove 27 is formed in the longitudinal direction in the center of the protrusion 13. It is. The gap between the protrusion 13 and the outer tube 20 is very small. The reason why the protrusion 13 is formed in the center of the second expanded deformation member 14 in the outward direction is as described in more detail in the description of the action of the pulverized coal blowing lance 100 according to the present invention. Even if the lance 100 is bent due to high temperature and its own weight, the outer surface of the inner tube 10 by the protrusion 13 does not contact the inner surface of the outer tube 20 to maintain the original shape as it is .

In addition, the groove 27 formed at the center of the protrusion 13 allows oxygen to be supplied through the groove 27 even when the protrusion 13 is in contact with the outer tube 20. That is, since oxygen may be supplied through the recess 27 and cooling action by oxygen occurs, the protrusion 13 may be completely prevented from adhering to the outer tube 20.

Meanwhile, as illustrated in FIG. 8, the tip 18 of the pulverized coal injection lance 100 has an inner diameter of the tip 18 of the outer tube 20 equal to the inner diameter of the inner tube 10. ).

Hereinafter, the operation of the pulverized coal injection lance 100 according to the present invention will be described.

The pulverized coal blown lance 100 inserted into the blow pipe 60 to face the tuyere 59 is in a high temperature environment and needs cooling by oxygen.

However, if the supply of oxygen is stopped for various reasons, such as a sudden occurrence of trouble in the pulverized coal production facility, individual blowout due to branch pipe characteristics, and failure of the oxygen check valve 65, the cooling effect by oxygen cannot be expected. 100 is raised to a higher temperature than when cooling with oxygen is achieved. In particular, the hot portion 57 disposed in the hollow 62 of the blow pipe 60 of the pulverized coal injection lance 100 is elevated to a higher temperature because it is directly exposed to a high temperature atmosphere than other portions.

Accordingly, as shown in FIG. 3, the portion 55 of the pulverized coal injection lance 100 entering the hollow 62 from the blow pipe 60 is softened by high temperature and the inner tube 10. ) Is bent downward under the influence of the weight of the portion disposed in the hollow 62.

When the bending occurs as described above, the protrusion 13 comes into contact with the inner surface of the outer tube 20 before the inner tube 10. Therefore, the outer surface of the inner tube 10 is not in direct contact with the outer tube 20 and is separated from the outer tube 20 by the size of the protrusion 13. That is, the inner tube 10 is bent by the protrusion 13 only between the inner tube 10 and the outer tube 20 in the initial state to maintain the shape of the initial state.

On the other hand, even when the protrusion 13 is in contact with the outer tube 20, oxygen is supplied through the groove 27 through the groove 27 formed in the center of the protrusion 13, thereby cooling the oxygen by As a result, the protrusions 13 do not completely adhere to the outer tube 20.

5 shows that the first expansion deformation member 14 and the second expansion deformation member 16 mounted on the first and second grooves respectively formed on the upper and lower portions of the outer circumferential surface 12 of the inner tube 10 have a high temperature. It shows that the thermal expansion in the atmosphere of.

As can be seen from the arrows shown in FIG. 5, the inner tube 10 has a larger thermal expansion coefficient than that of the first expansion deformation member 14, thereby thermally expanding inward in the longitudinal direction of the first expansion deformation member 14. The first expanded deformation member 14 is subjected to a compressive force in the longitudinal direction inward.

On the contrary, since the second expansion deformation member 16 has a larger coefficient of thermal expansion than the inner tube 10, the second expansion deformation member 16 thermally expands outward in the longitudinal direction of the second expansion deformation member 16. The longitudinal expansion force is received by thermal expansion of the second expansion-deformation member 16.

As described above, the inner tube 10 has a bending force upward due to the longitudinal thermal expansion occurring inside the first expanding deformation member 14 and the longitudinal thermal expansion occurring outside the second expanding deformation member 16. Accordingly, the bending caused by the high temperature softening action and the weight of the hollow arrangement 57 by the bending force acting upward is compensated.

As a result, the inner tube 10 has a high temperature due to the action of preventing excessive bending of the inner tube 10 by the protrusion 13 and the bending force due to thermal expansion of the first and second expansion-deformation members 14 and 16. Keep the original shape without bending.

Meanwhile, the oxygen supplied through the space between the outer tube 20 and the inner tube 10 is supplied while being rotated by the screw 22 as shown in FIG. 8 and by the nozzle 19 of the tip portion 18. Discharged at high pressure. Accordingly, when the pulverized coal 80 is discharged to the blast furnace 70, the high-pressure oxygen is rotated to penetrate into the pulverized coal 80, so that the pulverized coal 80 and oxygen are mixed smoothly, so the pulverized coal 80 is actively burned. .

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

The pulverized coal injection lance 100 according to the embodiment of the present invention enters the hollow 62 in the blow pipe 60 about 600 mm from the front end portion 18 to the rear end.

A first groove 15 is formed in a portion 55 where the pulverized coal injection lance 100 enters the hollow 62 in the blow pipe 60, that is, an upper portion of the inner circumferential surface 12 of the entry portion 55. And the second groove 17 is formed in the lower portion. As shown in FIGS. 5 and 6, the first and second grooves 15 and 17 have a rectangular shape.

The first groove 15 is formed in the upper portion of the outer circumferential surface 12 of the inner tube 10, approximately 90 ° to 180 °, more preferably around 130 ° from the circumferential reference point at the reference point, and the second groove 17. ) Is formed in the lower portion of the outer circumferential surface 12 of the inner tube 10, approximately 270 ° to 360 °, more preferably around 300 ° from the reference point.

The first groove 15 has a depth of 2 mm, a length of 250 mm and a width of 30 mm. In addition, the second groove 17 also has a depth of 2 mm, a length of 250 mm and a width of 30 mm.

The first groove 15 is coated with a coating layer which is a first expansion-deformation member 14 by thermally spraying a heat-resistant alloy powder having a thermal expansion coefficient smaller than that of the inner tube 10 with argon (Ar) or hydrogen (H ₂ ) plasma. Formed. The powder is a heat resistant alloy powder having a composition of 42.2% Ni, 14.2% Cr, 29.7% Al, 0.8% CoZ, 1.2% ZrO 2 and other Fe and impurities. In addition, the coating layer was formed so that the thickness is approximately 2.5 ~ 3 mm.

The second groove 17 is formed of a copper plate made of copper (Cu) material having a thermal expansion coefficient greater than that of the inner tube 10 material SUS310 as the second expansion deformation member 16 and having the same size as the second groove 17. Inserted. The copper plate was smoothly processed to coincide with the inner surface of the second groove 17 and the thickness was formed to be slightly smaller than the depth of the second groove 17.

As shown in FIGS. 5 and 6, the copper plate is in contact with the second groove 17 in the longitudinal direction of the pulverized coal injection lance 100 so as not to be separated from the second groove 17. After being closely adhered to and covered with a metal piece 28 of the same material (SUS310), the fillet was welded with a welding rod 29 of the material of the inner tube 10 (SUS310).

Meanwhile, as illustrated in FIG. 5, the pulverized coal injection lance 100 has a nozzle 19 having the same inner diameter as the inner diameter of the inner tube 10 as shown in FIG. 5. Formed.

Table 1 shows the internal temperature and surface temperature of the pulverized coal injection lance 100 and the conventional pulverized coal injection lance when oxygen is supplied to the coolant and air is supplied when blowing the pulverized coal 80 at a high temperature of 1200 ° C. The bending displacement of the inner tube and the bending displacement of the inner tube of the pulverized coal injection lance according to the present invention are shown. The sign of the bending displacement is indicated by the magnitude of the displacement from the coating layer in the direction of the copper plate and the magnitude of the displacement in the opposite direction as the-magnitude.

As can be seen from the results of Table 1, the bending displacement of the pulverized coal injection lance 100 according to the present invention was much smaller than that of the conventional pulverized coal injection lance when oxygen or air is blown or when the oxygen injection is stopped.

Pulverized coal injection lance internal temperature (℃) Pulverized coal injection lance surface temperature (℃) Conventional pulverized coal injection lance bending displacement (mm) Pulverized coal injection lance deflection displacement according to the present invention (mm) Oxygen injection 210 300 10 -3 Air blowing 280 350 13 -2 Oxygen blown off 520 610 23 3

On the other hand, oxygen supplied through the space between the outer tube 20 and the inner tube 10 is supplied while being rotated by the screw 22 and discharged at a high pressure by the nozzle 19 of the tip. Accordingly, when the pulverized coal 80 is discharged to the blast furnace 70, the high-pressure oxygen is rotated to penetrate into the pulverized coal 80 so that the pulverized coal 80 and oxygen are smoothly mixed and the pulverized coal 80 is actively burned. lost.

The pulverized coal injection lance 100 according to the present invention through the above embodiment prevents excessive bending of the inner tube 10 by the protruding portion 13 and thermal expansion of the first and second expansion deformation members 14 and 16. The original shape was maintained without bending at high temperature by the action of the bending force.

In addition, through the nozzle 19 formed at the tip of the pulverized coal injection lance 100, the combustion of pulverized coal and oxygen is actively performed to improve the combustion efficiency.

As described above, according to the present invention, the pulverized coal injection lance suppresses warpage of the blown lance, thereby preventing the blowholes from being broken by the pulverized coal discharged from the pulverized coal blown lance, thereby preventing operation interruption. It has the effect of raising. In addition, the pulverized coal blown lance according to the present invention has a more improved combustion effect by smooth mixing of pulverized coal and oxygen.

Claims (5)

In the pulverized coal injection lance composed of a double pipe of the outer tube and the inner tube in the blow pipe located in the blast furnace inside the blast furnace to inject pulverized coal into the blast furnace, A first expansion-deformation member (14) having a coefficient of thermal expansion smaller than that of the inner tube (10) above the inner tube (10) outer peripheral surface (12) disposed in the hollow (62) of the blow pipe (60); A second expansion-deformation member (16) having a coefficient of thermal expansion greater than that of the inner tube (10) below the inner tube (10) outer peripheral surface (12) disposed in the hollow (62) of the blow pipe (60); Including, The pulverized coal injection lance is characterized in that it does not bend by self weight in a high temperature atmosphere by utilizing the difference in thermal expansion between the first and second expansion deformation members (14) (16) and the inner tube (10). The method of claim 1, The first expanded deformation member 14 is formed of a coating layer in which thermally-alloyed powder is thermally sprayed into the plasma, and the second expanded deformation member 16 is formed of a copper (Cu) plate. The method of claim 1, The first groove 15 and the second groove 17 in the upper and lower portions of the outer circumferential surface 12 of the inner tube 10 so as to increase the expansion effect by the first and second expansion deformation members 14 and 16. And forming the first and second expansion deformation members (14) and (16) in the first and second grooves, respectively. The method of claim 1, The inner tube 10 is bent at the center of the second expansion deformation member to form a protrusion 13 to prevent the inner tube 10 from being attached to the inner surface of the outer tube 20, and at the center of the protrusion 13. A pulverized coal injection lance, characterized in that to form a groove (27) to increase the contact area with oxygen to increase the cooling effect. The method of claim 1, In order to improve combustion efficiency by smooth mixing of the pulverized coal 80 and oxygen, a nozzle 19 is formed in the outer end portion 20 of the pulverized coal injection lance such as the inner diameter of the inner tube 10. Pulverized coal injection lance characterized in that.