JP3846177B2 - Blast tuyere of shaft furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blower tuyere provided in a shaft furnace used for metal smelting, metal smelting reduction, processing of metal-containing materials and wastes, etc., in particular, a blast furnace blower tuyere and a carbon-filled layer type It relates to the lower tuyere of the smelting reduction furnace.
[0002]
[Prior art]
In shaft furnaces such as blast furnaces and metal smelting reduction furnaces used for metal smelting, gas containing oxygen and other gases is usually introduced from the top of the furnace, with raw materials and fuel charged from the top of the furnace, and installed in the lower part of the furnace. As the fuel is burned in the furnace, the heat generated by the combustion of fuel in the furnace causes various reactions such as metal reduction, decomposition of other substances, and melting, and the generated molten metal and molten slag are discharged from the hearth. Is done.
[0003]
In such a shaft furnace, coke is usually used as fuel charged from the top of the furnace, and this coke serves as a spacer in the furnace. That is, according to FIG. 2, which shows the in-furnace situation of a blast furnace for smelting iron ore, iron ore charged from the top of the blast furnace 101 is supplied to the furnace from a plurality of blower tuyere 102 provided in the lower part of the furnace. Air blown into the inside or oxygen-enriched air is heated and reduced by a high-temperature reducing gas generated by burning coke charged from the top of the furnace together with iron ore and melted. In the blast furnace 101, this zone where the iron ore melts is called a cohesive zone 103. At the level below the cohesive zone 103, the coke packed layer 104 is formed, and the molten metal and molten slag flow downward through the gap of the coke packed layer 104 as indicated by the arrow a in FIG. is there. In FIG. 2, reference numeral 105 denotes a top layer, and 106 denotes a massive band.
[0004]
Here, the temperature inside the furnace of the shaft furnace is the highest at the coke fire point before the blower tuyere, and in the shaft portion where the high temperature reducing gas generated here rises, The temperature has decreased due to heat exchange with the raw fuel. Moreover, in the level below a ventilation tuyere, heat | fever is transmitted because a molten metal and molten slag flow to a hearth, and temperature falls as it becomes below.
[0005]
Even in a coke packed bed type smelting reduction furnace having a multistage blower tuyere as disclosed in JP-A-10-265815, a coke packed bed is formed in the furnace by coke charged from the top of the furnace. Here, the oxygen-enriched air blown from the upper and lower blowing tuyere is blown to burn the coke, and the high-temperature reducing gas rises toward the top of the furnace, whereby the temperature of the coke in the shaft portion is raised.
[0006]
In this coke packed bed type smelting reduction furnace, iron ore or metal-containing material is blown in from the upper tuyere with the blowing of oxygen-enriched air, the temperature rises and the reduction proceeds, and this coke burns in front of the lower tuyere. The generated heat is finally reduced and melted to generate molten metal and molten slag. FIG. 3 shows a conceptual diagram of the shaft furnace in the vicinity of the blower tuyere. In front of the blower tuyere 201, molten metal and molten slag 203 flow down in the gap between the coke 202 in the coke packed bed and collect in the hearth. Heat transfer to the hearth is achieved.
[0007]
As described above, since the temperature inside the shaft furnace is the highest in the coke before the blower tuyere, the blower tuyere is subjected to extremely severe heat load. For this reason, the blower tuyere is usually water-cooled inside, and its material is also made of copper with good heat transfer. However, even with such water cooling, when the molten metal and molten slag are in direct contact with the blower tuyere, it is not possible to avoid melting of the blower tuyere. May leak. In such a case, it is necessary to interrupt the operation and replace the ventilation tuyere.
[0008]
In the shaft furnace, heat transfer in the furnace is performed smoothly while stable operation continues, but when the operation is interrupted and the blowing is stopped as described above, the coke combustion in front of the blowing tuyere is performed. Stops and no heat is generated, so the temperature in the furnace decreases due to heat removal from the furnace body. When such operation is interrupted for a long time, and the temperature in the furnace, especially in the hearth, has decreased, the molten metal generated in the furnace when the blowing from the blowing tuyeres is resumed. In some cases, the molten slag solidifies at the hearth. Or even if it does not reach coagulation | solidification, the viscosity of a fluid will deteriorate extremely by temperature fall, and liquid permeability will worsen.
[0009]
In such a case, new molten metal and molten slag are generated and flowed down in the vicinity of the shaft portion above the blower tuyere or the blower tuyere, while solidified material is present in the hearth portion. These melts are prevented from flowing down. For this reason, the molten metal and molten slag that do not flow down to the hearth stay in front of the blower tuyere. When such accumulated molten metal and molten slag come into contact with the air blowing tuyere, the air blowing tuyere is exposed to an excessively high temperature, resulting in a situation where the air blowing tuyere is melted.
[0010]
When the blower tuyeres are melted in such a manner, the molten metal and the molten slag come in contact from below the blower tuyere, so that the lower front part of the blower tuyere is melted.
It is thought that the liquid permeability of the coke packed bed below the blower tuyere in the furnace deteriorates because the heat of the part is insufficient, but the combustion gas generated by the combustion reaction before the blower tuyere is Usually, since it flows to the gas outlet located above the furnace, it is difficult to supply heat directly from the combustion gas to the coke in that portion. Therefore, in order to raise the temperature of the said part, it is necessary to supply heat by dripping the molten metal or molten slag produced | generated above the ventilation tuyere, and contacting the coke of the said part. However, as described above, the molten metal and the molten slag to be dropped are retained in front of the air blowing tuyeres because the liquid permeability of the portion is poor, and cause melting of the air blowing tuyere.
[0011]
In order to break such a vicious cycle, conventionally, the blower tuyere is removed from the shaft furnace and oxygen is supplied to the coke packed bed in the furnace via a pipe, thereby burning the coke and the flow of the melt. After the passage was formed, the blowing tuyere was again installed in the shaft furnace and the blowing was resumed to prevent the molten metal and molten slag from staying in front of the blowing tuyere.
[0012]
[Problems to be solved by the invention]
However, even if measures are taken to prevent the molten metal and molten slag from staying, the melt flow path formed by the oxygen supplied by the pipe flows down to the front of the blower tuyere. When there is a large amount of molten metal and molten slag flowing down due to the balance with the amount of molten metal, etc., the molten material stays in front of the air blowing tuyere, and the air blowing tuyere is melted again. I was forced to stop again.
[0013]
Therefore, the present invention has been made in view of the above-described problems, and the purpose thereof is to prevent melting caused by deterioration of liquid permeability in the hearth part below the blower tuyere after stopping the blowing. An object of the present invention is to provide a blower tuyere for a shaft furnace that can be effectively prevented.
[0014]
[Means for Solving the Problems]
The present invention has been conceived by considering and examining the operating conditions and the conditions in the furnace when the blower tuyeres are melted by the molten metal and molten slag retained in the furnace.
That is, the blower tuyere of the shaft furnace according to claim 1 of the present invention includes a cylindrical blower tuyere having a blower passage penetrating in the front-rear direction attached to the shaft furnace, and an outer periphery of the blower tuyere part One end is fixed to the surface, the other end protrudes forward from the front surface of the blower tuyere, and one end is fixed near the front end of the blower channel of the blower tuyere. An intubation tube protruding forward from the front surface, and a space between the outer intubation tube and the inner intubation tube is filled with a refractory.
[0015]
Moreover, the blower tuyere of the shaft furnace which concerns on Claim 2 among this invention is characterized by the said external intubation and the said internal intubation being steel in the invention of Claim 1. Furthermore, in the invention according to claim 1 or 2, the blow tuyere of the shaft furnace according to claim 3 of the present invention is such that the inner intubation has an inner diameter that is substantially the same as a diameter at a front end of the air flow passage. It is characterized by.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a blower tuyere of a shaft furnace according to the present invention.
In FIG. 1, the ventilation tuyere 1 is equipped with the copper ventilation tuyere part 10 of the same structure as the copper ventilation tuyere used normally. This blower tuyere portion 10 is formed in a cylindrical shape having an outer diameter that gradually decreases from the rear to the front, and has a blower passage 11 that passes through the front and rear (right and left in FIG. 1), and is used for metal smelting. It is attached to the bottom of the furnace of a blast furnace (not shown) by driving. In addition, a cooling water passage 13 through which cooling water for cooling the tuyere passes is formed in the blower tuyere portion 10.
[0017]
A steel outer insertion tube 20 is fixed to the outer peripheral surface of the blower tuyere 10. One end of the outer insertion tube 20 is fixed to the outer peripheral surface of the blower tuyere 10 by welding, and the other end projects forward from the front surface 14 of the blower tuyere 10. In FIG. 1, the outer insertion tube 20 has a truncated cone side surface shape having an outer diameter and an inner diameter that gradually decrease from the rear to the front, but may be a cylindrical shape having a constant outer diameter and inner diameter.
[0018]
Further, a steel inner tube 30 is fixed in the vicinity of the front end 12 of the air flow passage 11 of the air supply tuyere 10. One end of the inner tube 30 is fixed to the vicinity of the front end 12 of the air flow passage 11 by welding, and the other end projects forward from the front surface 14 of the air blowing tuyere 10 and extends to the same surface as the front surface of the outer tube 20. ing. The inner intubation 30 has a cylindrical shape having an inner diameter that is substantially the same as the diameter at the front end 12 of the air flow passage 11.
[0019]
The space between the outer insertion tube 20 and the inner insertion tube 30 is filled with an irregular refractory 40 so as to cover the outer peripheral surface and the front surface 14 of the blower tuyere 10. The amorphous refractory 40 can be easily constructed by pouring a cast refractory. When the cast refractory is poured, if the outer intubation tube 20 and the inner intubation tube 30 are fixed to the blower tuyere 10 by spot welding, a part of the cast refractory flows from the gap of the welded portion. By flowing out, it is suitable for pouring the entire space between the outer intubation tube 20 and the inner intubation tube 30 and filling the refractory.
[0020]
Any material can be used as the material for the amorphous refractory 40 as long as it has durability against molten metal and molten slag in the furnace. In particular, a composition composed of alumina (Al ₂ O ₃ ) and silicon carbide (SiC) is suitable. Further, a stainless fiber may be added to the amorphous refractory 40. Thereby, when the blower tuyere 1 is driven into the lower part of the blast furnace, the strength can be improved against an impact caused by contact with the coke in the furnace. In addition, the outer intubation tube 20 and the inner intubation tube 30 not only function as a mold when constructing the irregular refractory 40 but also damage the irregular refractory 40 when the blower tuyere 1 is driven into the furnace bottom of the blast furnace. , And also has a function of preventing peeling. And since the outer intubation tube 20 and the inner intubation tube 30 are made of steel, the impact caused by the refractory 40, the outer intubation tube 20 and the inner intubation tube 30 coming into contact with the coke in the furnace when the blower tuyere 1 is driven into the furnace lower portion of the blast furnace. The strength against the can be further improved.
[0021]
Further, a plurality of steel anchors 41 are installed in advance on the outer peripheral surface and the front surface 14 of the blower tuyere 10 before filling with the irregular refractory 40, and the irregular refractory fire around these steel anchors 41. Object 40 is filled. Thereby, the intensity | strength of the amorphous refractory 40 is improved further.
In addition, since the blowing tuyere part 10 can utilize the normally used ventilation tuyere, you may spray the heat-resistant metal to the front surface 14 and outer peripheral surface of the blowing tuyere part 10 previously. As will be described later, the outer intubation tube 20, the inner intubation tube 30, and the amorphous refractory 40 of the blower tuyere 1 according to the present invention are placed in the bottom of the blast furnace for a while after being installed in the hearth of the furnace. It is a protective layer that protects the blower tuyere 10 against molten metal and molten slag that stay in the furnace when the liquidity is poor, and wears out for a while after the start of blowing. If there is a metal, it can be expected that the amorphous refractory or the like will function as a protective layer of the blower tuyere 10 even after wear and the same durability as a normal tuyere.
[0022]
When the blower tuyere 1 shown in FIG. 1 is installed in the lower part of the blast furnace, the blowout time is prolonged, the temperature in the furnace, particularly in the hearth, decreases, and the liquid permeability in the hearth becomes lower. Even when the molten metal and molten slag generated after the start of blowing flow down and stay in front of the blower tuyere 1 when the air is getting worse, the molten metal and molten slag are removed from the outer tube 20, the inner tube 30, In addition, it is possible to prevent the molten metal and molten slag from coming into direct contact with the blower tuyeres 10 made of copper, in contact with the amorphous refractory 40. For this reason, it is possible to prevent melting of the air blowing tuyere 10 immediately after the start of air blowing, and it is no longer necessary to stop air blowing due to this. Therefore, the temperature of the molten metal and molten slag staying in the poorly permeable part of the hearth is increased by the heat of the high-temperature molten metal and molten slag generated after the start of air blowing, and thereby the molten metal and molten slag are heated. Viscosity is lowered and the liquid permeability in the hearth can be improved.
[0023]
In the conventional ventilation tuyere, the blowing tuyere was melted before the temperature rise of the molten metal and molten slag staying in the poorly permeable part of the hearth, and the blowing was forced to stop. By doing so, it is possible to avoid melting of the blower tuyere and re-stop of the blower before raising the temperature of the retained molten metal and molten slag, and it is possible to continue stable operation.
[0024]
Here, once the irregular refractory 40 filled between the outer intubation tube 20 and the inner intubation 30 has good liquid permeability in the hearth, there is no problem even if it disappears. The material of the object 40 may be any material that can withstand molten metal and molten slag to some extent.
Further, since the inner intubation 30 has an inner diameter that is substantially the same as the diameter at the front end 12 of the air flow path 11, the air supplied from the air flow path 11 through the inner diameter of the inner intubation 30 into the furnace smoothly and without waste. Is called.
[0025]
As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change can be made.
For example, the attachment of the blower tuyere 1 is not limited to a blast furnace used for metal smelting, but a smelting reduction furnace used for metal smelting reduction, other metals used for treatment of metal-containing materials, waste, etc. It may be a shaft furnace.
[0026]
【Example】
In order to verify the effect of the present invention, the blower tuyere 1 shown in FIG. 1 was used as the lower tuyere of a metal smelting furnace having a two-stage tuyere with an internal volume of 140 m ³ .
The outer intubation tube 20 and the inner intubation tube 30 are made of SS400 steel, and are projected by 50 mm from the front surface 14 of the blower tuyere 10, respectively, by spot welding on the outer peripheral surface of the blower tuyere 10 and the vicinity of the front end of the blower channel 11. Fixed. Alumina (Al ₂ O ₃ ): 15% by weight, silicon carbide (SiC): 85% by weight so as to cover the outer peripheral surface and the front surface 14 of the blower tuyere 10 in the space between the outer tube 20 and the inner tube 30 The air-blowing tuyere 1 was prepared by pouring an amorphous refractory 40 in which 2 parts by weight of a stainless steel fiber (0.5 mm square x 25 mm) was externally mixed and poured into a composition having a% composition.
[0027]
In the operation of the above-mentioned metal smelting furnace, one day after the start of blowing, when blowing is stopped for replacing the tuyere due to inundation to the hearth due to suspension of blowing for 24 hours or more or damage to the blowing tuyere The number of times the lower tuyere was melted within 4 times of the 10 times when the conventional normal tuyere was used, whereas the vent tuyere 1 shown in FIG. 1 was used. If you did, there was nothing.
[0028]
【The invention's effect】
As described above, according to the blower tuyere of the shaft furnace according to claim 1 of the present invention, the cylindrical blower tuyere having a blower passage penetrating in the front-rear direction attached to the shaft furnace; One end is fixed to the outer peripheral surface of the blower tuyere part, and the other end is located in the vicinity of the front end of the blower channel of the blower tuyere part, an extrapolation tube projecting forward from the front surface of the blower tuyere part And the other end protrudes forward from the front surface, and the space between the outer intubation tube and the inner intubation tube is filled with a refractory. In the furnace, especially when the temperature of the hearth part is lowered and the liquid permeability in the hearth part is deteriorated, the molten metal and molten slag generated after the start of blowing flow down before the blowing tuyere. Molten metal and molten slag are externally intubated, internally intubated, and indefinite Contact the fire was these can melt metal and molten slag is prevented from direct contact with the blowing tuyere portion. For this reason, the melting loss resulting from the deterioration of the liquid permeability in the hearth part below the blower tuyere after stopping the blowing can be effectively prevented. As a result, stable operation can be continued.
[0029]
Moreover, according to the blower tuyere of the shaft furnace according to the second aspect of the present invention, in the invention according to the first aspect, the outer intubation tube and the inner intubation tube are made of steel. The strength against impact caused by contact of the refractory, the outer tube, and the inner tube with the coke in the furnace can be improved.
Furthermore, according to the blower tuyere of the shaft furnace according to the third aspect of the present invention, in the invention according to the first or second aspect, the inner intubation has an inner diameter substantially the same as a diameter at a front end of the blower flow path. Since it has, the ventilation supplied from the ventilation flow path through the inner diameter of the inner tube into the furnace can be performed smoothly and without waste.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a blower tuyere of a shaft furnace according to the present invention.
FIG. 2 is an explanatory diagram schematically showing the in-furnace situation of a blast furnace for smelting iron ore.
FIG. 3 is a conceptual diagram of a shaft furnace in the vicinity of a ventilation tuyere.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Blower tuyere 10 Blower tuyere part 11 Blower flow path 12 Front end 13 of a blower flow path 14 Cooling water passage 14 Front face of blower tuyere part 20 External insertion pipe 30 Inner intubation 40 Amorphous refractory 41 Steel anchor 101 Blast furnace 102 Tuyere 103 cohesive zone 104 coke packed layer 105 top layer 106 lump band 201 blower tuyere 202 coke 203 molten slag

Claims (3)

A cylindrical blower tuyere having a blower passage penetrating front and rear, attached to the shaft furnace, and one end fixed to the outer peripheral surface of the blower tuyere, the other end being more than the front of the blower tuyere An outer tube that protrudes forward, and an inner tube that has one end fixed in the vicinity of the front end of the blowing channel of the blowing tuyere and the other end protruding forward from the front surface,
A blower tuyere of a shaft furnace, wherein a space between the outer intubation and the inner intubation is filled with a refractory. The blow tuyere of a shaft furnace according to claim 1, wherein the outer intubation and the inner intubation are made of steel. The blower tuyere of a shaft furnace according to claim 1 or 2, wherein the inner tube has an inner diameter substantially the same as a diameter at a front end of the blower flow path.

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