JP2009035754A - Blasting tuyere for blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blasting tuyere for blast furnace which suppresses lowering of the blasting temperature at the tuyere portion, to such a sufficient degree to decrease a reducing material quantity used in the blast furnace, and is excellent in heat-insulation. <P>SOLUTION: This invention relates to the blasting tuyere 1 for blast furnace, having a heat-insulating material layer 3 and an inorganic material layer 4 on an interior surface 2, and the blasting tuyere 1 for blast furnace wherein the heat-insulating material layer 3 is arranged between the blasting tuyere 1 for blast furnace and the inorganic material layer 4, and the heat-conductivity of the heat-insulating material layer 3 is 0.1 W/mK or lower, is used. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a blast furnace blower tuyere for blowing hot air to a blast furnace, and in particular, a blast furnace blower tuyere that can reduce the amount of reducing material used in the blast furnace by increasing the insulation temperature of the blast furnace blower tuyere and raising the blowing temperature. It is about.

In order to reduce CO _{2 in} recent years, the steel industry is required to reduce the amount of reducing material used such as coke in a blast furnace. One method for reducing the amount of reducing material is to improve the heat insulation of the blast furnace air tuyeres.

The blower tuyere is used to blow hot air of about 1200 ° C. into the blast furnace, and its tip is exposed to a particularly high temperature in the blast furnace, so the inside is strongly cooled by water cooling. For this reason, when the hot air passes through the blower tuyere, it is cooled from the interior surface (the inner surface that is the blower surface of the cylindrical tuyere) and the temperature of the hot air is lowered. Then, the fall of the hot air temperature which passes through the inside is suppressed by improving the heat insulation of the interior surface of a ventilation tuyere. As a result, even if the air is blown at the same temperature as before, hot air at a higher temperature is blown into the furnace, so the amount of reducing material corresponding to the amount of heat can be reduced, and CO ₂ associated with the combustion can be reduced. It becomes.

As a technique for improving the heat insulation of the blast furnace air tuyere, for example, Patent Document 1 discloses a blast furnace tuyere having a ceramic tube installed on the interior surface of the air flow tuyere and having a gap between the interior surface and the ceramic tube. Has been. Further, for example, in Patent Document 2, Al ₂ O ₃ —SiO ₂ having a thermal conductivity of 5 kcal / mh ° C. (= 5.8 W / mK) or less between the blower tuyere interior surface and the ceramic tube. A blast furnace tuyere having a system-shaped refractory inserted therein is disclosed. Furthermore, for example, Patent Document 3, the air blowing tuyere interior surface and Cr ₂ O ₃ -Al ₂ O ₃ based blowing tuyere of the blast furnace which is formed a low thermal conductivity mortar layer between the sleeve is disclosed.
JP-A-2-240207 JP-A-2-240206 JP-A-3-130312

However, in the blast furnace tuyere disclosed in Patent Literature 1, heat removal from the reinforcing portion and the support portion outside the ceramic tube for forming the void is large, so that the heat insulating effect due to the void cannot be sufficiently obtained. There is a problem. Further, in the blast furnace tuyere disclosed in Patent Document 2, the lower limit value of the thermal conductivity of the amorphous refractory is not shown, but the Al ₂ O ₃ —SiO ₂ amorphous refractory in the examples is not shown. The thermal conductivity is 1.59 kcal / mh ° C. (= 1.85 W / mK), and sufficient heat insulation cannot be obtained at this level. The method disclosed in Patent Document 3 uses a low thermal conductivity mortar, but the thermal conductivity is 0.1 to 2 kcal / mh ° C. (= 0.12 to 2. 33 W / mK), and there is a problem that sufficient heat insulation cannot be obtained.

  The present invention has been made in view of the above circumstances, and its purpose is heat insulation that can suppress the air temperature from decreasing at the tuyere part to a degree sufficient to reduce the amount of reducing material used in the blast furnace. It is to provide an excellent blast furnace air tuyeres.

The features of the present invention for solving such problems are as follows.
A blast furnace blower tuyere having a heat insulating material layer and an inorganic material layer on the interior surface, the heat insulating material layer is installed between the blast furnace air tuyere and the inorganic material layer, and the heat conductivity of the heat insulating material layer is A blast furnace air tuyere characterized by being 0.1 W / mK or less.

According to the present invention, a decrease in the temperature of hot air blown into the blast furnace from the tuyere is suppressed, and hot air having a higher temperature can be blown into the furnace even if air is blown at the same temperature as before. For this reason, about the amount of reducing material used in a blast furnace, the amount of increase in the amount of hot air blown can be reduced, and CO ₂ generated with combustion of the reducing material can also be reduced.

  Moreover, since blast furnace operation by blowing hot air at a lower temperature than before becomes possible, energy saving operation can be realized.

  In FIG. 1, the schematic of the blast furnace ventilation tuyere which incorporates the heat insulating material layer and inorganic material layer which are used by this invention is shown. FIG. 1 is a cross-sectional view in a direction parallel to the axial direction (hot air blowing direction) of a blast furnace tuyere. A heat insulating material layer 3 and an inorganic material layer 4 are laminated in this order on the interior surface 2 of the tuyere body 1. It is a blast furnace ventilation tuyere with the structure. 5 is a cooling chamber. The tuyere body 1 and the inorganic layer 4 have a structure in which the heat insulating material layer 3 is sandwiched inside the tuyere body 1. And in this invention, the heat conductivity of the heat insulating material layer which contact | connects the interior surface of a tuyere shall be 0.1 W / mK or less.

  If the thermal conductivity of the heat insulating material layer is greater than 0.1 W / mK, the drop in hot air temperature cannot be sufficiently suppressed. On the other hand, the lower the thermal conductivity of the heat insulating material layer, the better. Therefore, it is not necessary to provide the lower limit value, but it is preferably 0.01 W / mK or more in consideration of practicality.

  Although the kind of heat insulating material used for a heat insulating material layer is not specified, it is difficult to make a heat conductivity into 0.1 W / mK or less using the mortar etc. which were conventionally used as a heat insulating material. Insulating materials with thermal conductivity of 0.1 W / mK or less, ceramic bulk, ceramic blanket, ceramic paper, ceramic board, ceramic cloth, ceramic tape, ceramic felt, ceramic fiber, ceramic block, regular and irregular refractories, A mortar etc. or those combinations are mentioned.

  When the heat insulating material layer is used alone, the pulverized coal blown into the tuyere together with hot air is remarkably adhered and the tuyere may be blocked, but the pulverized coal hardly adheres to the inorganic layer. Therefore, in order to protect the heat insulating material, an inorganic layer is provided on the hot air side of the heat insulating material layer. The inorganic material used for the inorganic layer is not particularly limited as long as it is a material that can withstand the temperature of the exposed hot air, and examples thereof include general ceramics and regular / indeterminate refractories. Further, the thermal conductivity is not particularly limited as in the heat insulating material layer, and is preferably 30 W / mK or less.

  The total thickness of the heat insulating material layer and the inorganic material layer is not particularly limited, but if the thickness is too thick, it becomes impossible to secure a necessary air blowing amount, and therefore it is preferably 1/5 or less of the tuyere interior diameter. .

  It is desirable to install the heat insulating material layer 3 and the inorganic material layer 4 on the entire interior surface of the blast furnace tuyere.

  Hereinafter, the present invention will be described by way of examples with reference to the drawings.

  As shown in FIG. 1, a blast furnace blower tuyere having a heat insulating material layer 3 and an inorganic layer 4 and a blast furnace blower tuyere having only an inorganic layer 4 as shown in FIG. 2 are used. Then, the temperature drop at the tuyere of hot air to be blown was compared.

  The materials shown in Table 1 were used as the heat insulating material and the inorganic material of the heat insulating material layer 3 and the inorganic material layer 4.

  Using the materials shown in Table 1 in the combinations shown in Table 2 as the heat insulating material layer 3 and the inorganic material layer 4, The blower tuyere shown in FIGS. No. 6 corresponds to the tuyere shown in FIG. Table 2 also shows the thermal conductivity and thickness of each heat insulating material layer and inorganic layer, and the total thickness of the heat insulating material layer and inorganic layer. The tuyere diameter was 165 mm in all cases.

  When the produced tuyere is installed in a blast furnace and the air flow rate and cooling water inlet temperature are constant, the temperature of hot air flowing into the air tuyere and the temperature when passing through the air tuyere are measured. Calculated as the temperature drop. The results are also shown in Table 2.

  According to Table 2, it has a heat insulating material layer and an inorganic material layer, and the thermal conductivity of a heat insulating material layer is in the range of this invention. In the case of using the tuyere of 1 to 5, the drop in the blowing temperature is 3 ° C. or lower, whereas No. having no heat insulating material layer is used. No. 6 which has a tuyere of No. 6 and a heat insulating material layer and an inorganic material layer, but the heat conductivity of the heat insulating material layer is outside the scope of the present invention. In the comparative examples of 7 to 9, the blast temperature decreased by 8 ° C. or more. In addition, in the comparative example, No. In the air blower tuyere No. 9, since the mortar of the heat insulating material layer was thick, the shrinkage amount of the mortar as an absolute amount was increased, the inorganic layer was damaged, and the durability was inferior.

  As described above, it has been found that by using a heat insulating material layer having a thermal conductivity within the scope of the present invention, a decrease in the blast temperature can be dramatically reduced.

It is the schematic of the cross section of the blast furnace ventilation tuyere which has equipped the heat insulating material layer and the inorganic substance layer. It is the schematic of the cross section of the blast furnace blast tuyere which equipped only the inorganic substance layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blast furnace blast tuyere body 2 Interior surface 3 Insulation layer 4 Inorganic layer 5 Water cooling

Claims (1)

  A blast furnace blower tuyere having a heat insulating material layer and an inorganic layer on an interior surface, wherein the heat insulating material layer is installed between the blast furnace blower tuyere and the inorganic material layer, and the heat conductivity of the heat insulating material layer is A blast furnace air tuyere characterized by being 0.1 W / mK or less.

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