JP5262018B2 - Blast furnace tuyere with tuyere ring and tuyere ring - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tuyere ring and a blast furnace tuyere with the tuyere ring installed therein which contribute to an increase in injection quantity of fine powdery coal and to formation of a stable raceway having depth and spread by optionally setting the blasting angle of hot-blast although an ordinary tuyere with the tuyere ring installed therein is used and a Laval tuyere is not used. <P>SOLUTION: The cylindrical tuyere ring 2b installed inside the blast furnace tuyere 1 is used, the cylindrical tuyere ring 2b being characterized in that at a part of the tuyere ring, the thickness of the tuyere ring is continuously changed so that the thickness of the tuyere ring reduces in an axial direction, and at a part opposite to the above part of the tuyere ring in a circumferential direction, the thickness of the tuyere ring is continuously changed so that the thickness of the tuyere ring increases in the axial direction. The blast furnace tuyere with the tuyere ring installed therein is characterized in that the above tuyere ring 2b is installed in the tuyere 1 in such a way that the upper part of the tuyere ring becomes thinner toward a blast-inlet side and becomes thicker toward a blast-outlet side, and the lower part becomes thicker toward the blast-inlet side and becomes thinner toward the blast-outlet side. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a tuyere tuyere with tuyere rings and tuling rings used in a blast furnace.

  Most blast furnace tuyere are made of copper with good thermal conductivity. Since hot hot air is supplied into the blast furnace through the tuyere, and the tip of the tuyere is directly exposed to the high temperature atmosphere in the furnace, the tuyere receives a large thermal shock. Therefore, in order to prevent breakage and prolong the life, high-flow-rate cooling water is allowed to flow inside the tuyere for forced cooling. Conventionally, a tuyere ring (heat insulating ring) is attached to the inner surface of the tuyere for the purpose of suppressing heat loss at the tuyere by cooling and preventing wear due to the ash component of the injected fuel. FIG. 8 shows an example of such a tuyere ring. A tuyere ring 2 a is installed on the inner surface side of the tuyere 1. 3 is a horizontal line, and 4 is the center line of the tuyere ring 2. The blowing angle in this case is downward a.

  In order to improve the thermal insulation of tuyere rings, the ring material has been frequently developed. Furthermore, the development of a wing rolling structure that can adjust the tuyere wind speed during wind reduction and rest, and the development of impact mitigation / protection methods applied to the refractory that constitutes the wing rolling have been carried out (for example, Patent Documents 1 to 3). 7).

  Conventionally, auxiliary fuel such as pulverized coal or waste plastic is supplied into the furnace as hot air from the tuyere via a lance as an alternative fuel for coke. Since the amount of gas increases due to the combustion of the auxiliary fuel, the flow velocity rapidly increases in the tuyere or in the blow pipe, and as a result, the blowing pressure increases. Thus, a Laval tuyere has been developed as a method of supplying auxiliary fuel into a furnace so as to be dispersed at high speed, and blowing it deeply into the blast furnace for combustion (see, for example, Patent Document 8).

The cross-sectional structure of the Laval tuyere is shown in FIG. The Laval tuyere 11 has a reduced diameter portion 14 in the pipe between the vicinity of the connecting portion of the blow pipe 12 and the tuyere tip 13, and the tip position of the pulverized coal blowing lance 15 is downstream of the reduced diameter portion 14. The curvature R is formed on the inner diameter side of the tuyere tip 13. Conventionally, the amount of pulverized coal that can be stably blown from a normal tuyere has been about 150 kg / pile iron t, but this Laval tuyere can stably blow 200 kg / pile iron t to 300 kg / pile iron t or more. It has become possible to reduce the amount of coke used. In addition, by providing the reduced diameter portion 14, the flow exiting the reduced diameter portion 14 can be a high-speed central flow and a flow that extends along the divergent portion on the downstream side of the reduced diameter portion, and the depth of the blast furnace is deep. In addition, it has become possible to form a raceway with a widening. Furthermore, the formation of the curvature R suppresses the generation of vortex flow outside the tuyere tip for hot air containing pulverized coal that has exited the tip of the tuyere tip. A raceway was formed and stable operation became possible.
Japanese Patent Publication No. 6-60333 Japanese Patent Publication No. 7-26133 Japanese Patent Publication No.7-113124 JP-A-9-227218 Japanese Patent Laid-Open No. 9-235162 Japanese Utility Model Publication No. 60-26117 JP-A-10-81910 JP 2000-192122 A

  In the operation of a blast furnace, it is difficult to change the blowing angle of hot air blown from the tuyere according to the operating conditions after installing the tuyere. By using Laval tuyere as described above, there is an effect that the amount of pulverized coal can be increased and a stable raceway with depth and spread can be formed, but once Laval tuyere is installed It is impossible to change the tuyere diameter and angle during operation. In addition, the Laval tuyere has a problem that the pressure loss at the reduced diameter portion is large.

  Therefore, the purpose of the present invention is to use an ordinary tuyere with a tuyere ring without using a laval tuyere, arbitrarily set the blowing angle of hot air, increase the amount of pulverized coal blown, and depth It is to provide a tuyere ring and a blast furnace tuyere equipped with tuyere rings that can contribute to the formation of a stable and stable raceway.

The features of the present invention for solving such problems are as follows.
(1) Cylindrical tuyere rolling ring installed inside the blast furnace tuyere, where the thickness continuously changes so that the tuyere ring thickness decreases in the axial direction at a part of the tuyere ring The tuyere ring is characterized in that the thickness of the tuyere ring continuously changes so that the thickness of the tuyere ring increases in the axial direction at a part facing the part of the tuyere ring in the circumferential direction. .
(2) The tuyere ring according to (1), wherein the tuyere ring has a thick part and a thin part at opposite positions on the circumference in the vicinity of one end in the axial direction of the tuyere ring.
The tuyere ring according to (3), (1), or (2) is configured such that the upper part is thinner toward the air inlet side, thicker toward the air outlet side, and the lower part is thicker toward the air inlet side and thinner toward the air outlet side. A blast furnace tuyere with a tuyere ring characterized by being installed in the mouth.
The tuyere ring according to (4), (1) or (2), with the upper part being thicker toward the air blowing side, thinner toward the air blowing side, and the lower part being thinner toward the air blowing side and thicker toward the air blowing side. A blast furnace tuyere with a tuyere ring characterized by being installed in the mouth.

  According to the present invention, the air blowing angle can be changed easily and inexpensively only by installing the feather rolling at the blast furnace tuyere. As a result, a raceway having a large depth can be formed, the impact received by the coke in the blast furnace is reduced, and the ventilation of the lower part of the furnace is improved by reducing the furnace core.

  Further, when the air permeability in the furnace is improved, the blowing pressure can be reduced, thereby reducing the load received by the tuyere and extending the life of the tuyere, thereby reducing the cost of the tuyere. .

  At the blast furnace tuyere, a feather rolling is installed inside the tuyere for the purpose of heat insulation, protection, diameter adjustment and the like. The tuyere ring of the present invention can change the air blowing angle from the tuyere only by installing the tuyere ring without exchanging the tuyere itself while performing thermal insulation of the tuyere. For this purpose, the thickness of the tuyere ring, which is usually uniform in the circumferential direction and the length direction, is continuously changed, and is a cylindrical tuyere ring, in which a part of the tuyere ring has a shaft. The thickness changes continuously so that the thickness of the tuyere ring decreases in the direction, and the thickness of the tuyere ring increases in the axial direction at the part facing the part of the tuyere ring in the circumferential direction. Thus, the thickness continuously changes. Thus, by changing the thickness of the tuyere ring, a passage having an angle different from the axial direction of the cylinder can be formed inside the tuyere ring, and the air blowing angle can be changed from the axial direction.

  When the tuyere ring has a structure in which the thickness is changed in the axial direction as described above, the end portion in the axial direction has a thick portion and a thin portion at opposite positions on the circumference.

  When such a tuyere ring is installed in the blast furnace tuyere, for example, when the air blowing angle is set downward from the current state, the upper part is thicker toward the inner side of the blast furnace (air blowing side), and the lower part is thinner toward the inner side of the blast furnace. Installed inside the blast furnace tuyere.

  Moreover, when making a ventilation angle upward from the present condition, it installs in the inside of a blast furnace tuyere so that a lower part is thicker inside a blast furnace, and conversely, an upper part becomes thin as a blast furnace inner side.

  When installing the tuyere ring above the tuyere, the thick part may hinder the installation of the lance or the inner diameter of the tuyere may be narrowed more than necessary. It is preferable that only a part of the portion is thinned to the thickness of a conventional tuyere ring.

  An embodiment of a blast furnace tuyere having a tuyere ring and a tuyere ring according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a tuyere, in which hot air is blown in the direction from left to right toward the paper surface, with the left corresponding to the furnace outer side and the right corresponding to the furnace inner side. The tuyere ring 2b of the tuyere 1 is designed so that the upper part is thicker toward the inner side of the blast furnace, and the lower part is thinner toward the inner side of the blast furnace, and is installed in the tuyere, when the air blowing angle is downward. 3 is a horizontal line, 4 is a center line when the thickness of the tuyere ring 2 is uniform, and in the case of a conventional tuyere ring, the blowing angle is downward a. When the tuyere ring 2b is thicker at the upper part of the blast furnace and thinner at the lower part of the blast furnace, the center line of the tuyere ring 2b is 5 and the blowing angle is downward b. FIG. 2 is a schematic view when the tuyere ring 2b before the blast furnace tuyere is installed is viewed from the inside of the furnace.

  Both ends in the length direction of the tuyere ring 2b are preferably subjected to processing such as rounding the corners as appropriate. In FIG. 1, only the blower outlet portion at the top of the tuyere ring 2b is made thin so that the blowing lance 6 such as pulverized coal does not overlap the tuyere ring 2b. That is, as a whole, the direction of the air blowing is changed so that the upper part of the tuyere ring 2b becomes thicker toward the air outlet side, but the thickness of the end part of the air outlet part of the upper part of the tuyere ring 2b is as thick as the conventional one. It is appropriate. Further, it is preferable that only the air inlet portion below the tuyere ring 2b is made thin so that the air inlet portion becomes wider. That is, as a whole, the lower part of the tuyere ring 2b is made thicker toward the air inlet side to change the direction of air blowing, but the thickness of the end of the air inlet part at the lower part of the tuyere ring 2b is about the same as the conventional thickness. It is appropriate.

  When both ends in the length direction of the tuyere ring 2b are made thin, the pulverized coal is prevented from adhering on the upstream side of the contracted part and the contracted part, and the flow velocity is maximized in the contracted part. From the viewpoint that charcoal can be blown into the blast furnace deep part, it is preferable that the tip of the blow lance 6 is located on the downstream side (closer to the blowout side) than the portion 7 with the smallest inner diameter of the tuyere.

  The case where the air blowing angle is set to be higher than the current state can be dealt with by using the one in which the upper and lower sides of the tuyere ring 2b are interchanged in FIG.

Next, in order to confirm the effect of changing the ventilation angle from the tuyere, using a 1/10 scale model of a blast furnace with an internal volume of 5500 m ³ , the relationship between tuyere angle, raceway depth and blowing pressure was investigated. The results will be described. FIG. 3 is a schematic diagram of the experimental apparatus, with the left side view and the right side front view. The furnace 22 was 395 × 120 × 500 cm, and a tuyere with an inner diameter of 10 mm (thickness 2 mm) was installed at a position of 185 cm from the bottom. From the upper hopper 21, plastic particles having a particle diameter of 3 mm are supplied into the furnace 22 as coke, discharged from the lower part, and hot air is blown from the tuyere 23 to form a raceway 24 in the furnace 22. The results are shown in FIGS. The tuyere angle is shown as negative for downward and positive for upward.

  As shown in FIG. 4, it can be seen that the larger the tuyere angle is, the lower the blowing pressure becomes. Further, as shown in FIG. 5, it can be seen that the raceway depth becomes maximum when the tuyere angle ranges from 20 ° downward to 20 ° upward. Therefore, it is understood that the tuyere angle is preferably downward, and when securing the raceway depth is taken into consideration, it is understood that the installation of the wing sleeve with the tuyere angle of 20 ° downward is optimal for stable operation.

  Therefore, the ability to adjust the tuyere angle is very effective in actual operation. By using a tuyere equipped with the tuyere ring of the present invention as shown in FIG. 1, the conventional tuyere angle (air blowing angle a: usually inclined downward in the range of 3 ° to 9 °), Further, the same effect can be obtained as when the tuyere inclined downward (air blowing angle b) is used. That is, the same effect as changing the installation angle of the tuyere can be obtained only by replacing the tuyere ring.

  There is no need to replace the tuyere itself, and the tuyere ring can be installed in the tuyere at any time, such as when there is no wind, so it can be replaced with a conventional tuyere ring without affecting the operation schedule. Can be used. In order to equalize the circumferential balance in the blast furnace, it is desirable that the tuyere of the present invention be installed in all tuyere of the blast furnace. Or it is desirable to arrange | position so that it may become equal in the circumferential direction.

  Examples of the present invention will be described below.

In a conventional blast furnace with a uniform tuyere ring installed at the tuyere, with an internal volume of 5500 m ³ , the coke ratio is 370 kg / pig iron t, the amount of pulverized coal blown is 110 kg / pig iron t, and the reducing material ratio is 480 kg. / Operation was performed under the condition of pig iron t (conventional example). During the periodical wind breaks, the same tuyere rings as shown in FIG. 1 were installed in all tuyere tuyeres for operation (invention example). The thickness of the tuyere ring in the conventional example was 7 to 10 mm and the air blowing angle was 8 ° downward. In the present invention example, the thickness of the blast furnace ring is 7 mm at the thin part and 20 mm at the thickest part. The air blowing angle was designed to be 10 ° downward.

The results of measuring the blast furnace ventilation resistance (K _L ) and the blowing pressure are shown in FIGS.

  When the operation of the conventional example is compared with the operation of the example of the present invention, it can be seen that the ventilation resistance and the blowing pressure are reduced by applying the present invention. It can also be seen that the fluctuation range of the blowing pressure is reduced and the operation is stabilized.

The sectional view of a tuyere which shows one embodiment of the present invention. The front view of the tuyere ring of FIG. The schematic diagram of an experimental apparatus. The graph which shows the relationship between a tuyere angle and ventilation pressure. A graph showing the relationship between tuyere angle and raceway depth. The graph which shows the measurement result of furnace lower part ventilation resistance. The graph which shows the measurement result of ventilation pressure. Sectional drawing of a conventional tuyere. Sectional view of Laval tuyere.

Explanation of symbols

1 tuyere 2 (2a, 2b) tuyere ring 3 horizontal line 4 tuyere ring center line 5 tuyere ring 2b center line 6 blowing lance 7 portion with the smallest tuyere inner diameter 8 tuyere inner diameter 11 laval tuyere 12 blow pipe 13 tip of tuyere 14 reduced diameter part 15 pulverized coal blowing lance 21 upper hopper 22 furnace 23 tuyere 24 raceway a air blowing angle b air blowing angle

Claims (4)

Cylindrical feather rolling installed inside the blast furnace tuyere,
In the vicinity of the center along the axial direction of the tuyere ring, the thickness continuously changes so that the thickness of the tuyere ring decreases in the axial direction, and in the circumferentially opposed part near the center , the axial direction The tuyere ring is characterized in that the thickness continuously changes so that the thickness of the tuyere ring increases.   The tuyere ring according to claim 1, wherein the tuyere ring has a thick part and a thin part at opposite positions on the circumference in the vicinity of one end in the axial direction of the tuyere ring.   The tuyere ring according to claim 1 or 2 is installed in the tuyere so that the upper part is thinner toward the air blowing side, thicker toward the air blowing side, and the lower part is thicker toward the air blowing side, and thinner toward the air blowing side. A blast furnace tuyere equipped with a tuyere ring characterized by that.   The tuyere ring according to claim 1 or 2 is installed in the tuyere so that the upper part is thicker toward the air blowing side, thinner toward the air blowing side, and the lower part is thinner toward the air blowing side, and thicker toward the air blowing side. A blast furnace tuyere equipped with a tuyere ring characterized by that.

Images