JP4720260B2 - Method and apparatus for injecting reducing material into blast furnace - Google Patents

Description

  The present invention relates to a reducing material for a blast furnace in which at least two kinds of reducing materials among a solid reducing material, a liquid reducing material, and a gas reducing material are blown into the blast furnace through a lance provided through a blower pipe of the blast furnace. The present invention relates to a blowing method and apparatus.

  Coke, which is used as a reducing material in blast furnaces that produce pig iron, generally requires expensive strong caking coal as a raw material, and costs for construction, operation, repair, etc. of the coke oven that is its production equipment. Expensive. For this reason, reduction of the pig iron manufacturing cost by reduction of the usage-amount of coke in a blast furnace is desired.

  In order to achieve the above object, it has been practiced to use a large amount of pulverized coal that is cheaper than coke or to use a synthetic resin material contained in waste as a reducing material for a blast furnace. Furthermore, in order to suppress the recent rise in coal prices and the emission of carbon dioxide gas, which is feared to act as a global warming gas, liquid reducing materials such as heavy oil with a higher hydrogen content than coal In addition, blowing of gas reducing materials such as methane gas and city gas has been attracting attention.

As a method for stably injecting these reducing materials into the blast furnace, for example, in Patent Document 1, by blowing a plurality of types of reducing materials from the same blast furnace tuyere, one reducing material is blown due to equipment trouble or the like. A technique has been disclosed in which, even when it is not possible to prevent the reduction, the other reducing material can be continuously blown to prevent a sudden reduction in the reducing material ratio.
JP-A-10-306302

  As a result of conducting a combustion test in a test furnace with respect to the method disclosed in Patent Document 1, the inventors have confirmed that the blowing pressure increases and the fluctuation further increases.

  The present invention has been made to solve such problems of the prior art, and an object of the present invention is to provide a method and apparatus for stably injecting a plurality of types of reducing materials into a blast furnace.

The inventor considered the cause of the increase in the blowing pressure and the fluctuation in the conventional example, and further considered the countermeasures against it as follows.
There are roughly two possible causes of the increase in the blowing pressure and its fluctuation. This is due to the solid reducing material blown from the tuyere and due to coke pulverization. These will be considered separately below.

(1) What is caused by the solid reducing material blown from the tuyere The cause caused by the solid reducing material blown from the tuyere is considered as follows.
Since the burning rate of the reducing material is generally faster in the order of gas, liquid, and solid, the gas reducing material burns first inside the blower tube or tuyere. The oxygen for burning the liquid reducing material and the solid reducing material is consumed by the combustion of the gas reducing material, and the oxygen necessary for the burning of the liquid reducing material and the solid reducing material is insufficient. It can be considered that unburned material such as “soot” is generated, which fills voids in the coke packed bed in the combustion furnace and clogs.
Therefore, as a countermeasure against the above cause, it is effective to supply the liquid reducing material and the solid reducing material to a region different from the region where oxygen is consumed by the gas reducing material. More specifically, it is effective that the extension lines in the blowing direction of the reducing material to be blown do not intersect.

In addition, as a cause of the generation of unburned materials, in addition to the oxygen consumption by the gas reducing material described above, the solid reducing material is inferior in the first place, so even if it is supplied into the furnace, it cannot be burned completely. In some cases, it remains as unburned material.
As a countermeasure against this, it is effective to lengthen the residence time in the high temperature region before being supplied into the furnace so that it can be burned immediately when supplied into the furnace. For this purpose, it is effective to position the solid reducing material blowing position as far as possible from the blast furnace axis, that is, to arrange the tip position of the solid reducing material blowing lance behind the tip of the tuyere.

(2) What is attributed to coke pulverization As a cause of the increase in air pressure and fluctuation, coke pulverization in the lower part of the blast furnace can be considered. Hereinafter, the pulverization behavior of coke and the suppression of pulverization will be examined.
The coke forms a packed bed inside the blast furnace, but is combusted and gasified together with the unburned portion of the above-mentioned blown reducing material inside the furnace rather than the tuyere. Coke pulverization is largely caused by a deterioration reaction represented by Formula 1 and Formula 2.
C (coke) + CO ₂ = 2CO ・ ・ ・ (Formula 1)
C (coke) + H ₂ O = CO + H ₂ (2)

Since the reactions of Formula 1 and Formula 2 have a slow reaction rate, the reaction occurs on the surface of the coke mass, and at the same time, CO ₂ and H ₂ O gas enter the interior of the coke mass and react to make the coke mass porous. Quality. The strength of the porous coke lump is reduced, and the coke lump is easily pulverized when the coke lump is moved by the energy of the blow and receives an impact. From this, it can be understood that coke is easily pulverized when CO ₂ and H ₂ O gas accompanying the combustion of the blown-in reducing material is supplied from the blast furnace air duct or tuyere.

Here, the gas reducing material and the liquid reducing material among those injected as the reducing material will be described below using saturated hydrocarbon C _n H _{2n + 2} . However, in actual use, anything may be used as long as it acts as a reducing material in the blast furnace, and it may be an unsaturated hydrocarbon, an aromatic hydrocarbon, a mixture with a saturated hydrocarbon, or the like.
The distinction between gas and liquid is defined by the state at normal temperature (25 ° C.) and normal pressure (1 atm, 1013 hPa). The gas reducing material is n to 1 to 4, and the liquid reducing material is n There are about 5 or more.

For example, butane with n = 4 has a boiling point of about 1 ° C. under atmospheric pressure and is a gas at room temperature and normal pressure, but liquefies at room temperature when the pressure reaches about 3 atmospheres. In such a case, since it is a gas at normal temperature and normal pressure, it is treated as a gas. When butane is used as a gas reducing material, pressure is applied to blow it into the blast furnace, but if it is preheated up to several tens of degrees and the piping is kept warm, it can be handled as a gas reducing material that is easy to handle. .
When n = 5 pentane, it becomes liquid at room temperature and normal pressure, so it is treated as a liquid. In order to handle pentane as a gas under blast furnace blowing conditions, the preheating temperature rises to about 100 ° C., making it difficult to preheat and keep warm, and in reality it is difficult to handle it as a gas.

As described above, when CO ₂ and H ₂ O gas accompanying combustion of the blown reducing material are supplied, the coke is easily pulverized. The details of this point and the countermeasures will be discussed below.
First consider gas reducing materials. It gaseous reducing agent is generally in fart Equation 3 shown below to produce CO and H _2, further CO and H ₂ produced in the formula 3 is 2-stage combustion to produce CO ₂ and H ₂ O by oxidation It has been known.
C _n H _{2n + 2} + n / 2 ・ O ₂ = n ・ CO + (n + 1) ・ H ₂・ ・ (Formula 3)

Therefore, for the gas reducing material, by suppressing the combustion of up to two stages as much as possible and generating CO ₂ and H ₂ O, by supplying one stage of combustion gas to the combustion zone inside the blast furnace where coke exists, Coke deterioration can be suppressed and pulverization can be suppressed. To this end, contrary to the case of the solid reducing material, it is effective to place the blowing position of the gas reducing material as close to the blast furnace axis as possible, that is, to arrange the lance tip position close to the tuyere tip.

  Various combustion analyzes (mathematical model calculations) were conducted to examine the position of the gas reducing material injection for obtaining such effects sufficiently. As a result, it was found that at least the tip position of the lance should be within 200 mm from the tuyere, and more desirably within 50 mm.

Next, the liquid reducing material will be examined. In the case of a liquid reducing material, since _n of C _n H _{2n + 2} is large, n is first reduced to 1 to 4 by thermal decomposition, and then combustion gasification by Equation 3 occurs, and finally CO ₂ and It will burn to H ₂ O. For this reason, the liquid reductant blowing position is located behind the tip of the tuyere than the gas reductant blowing position as much as thermal decomposition occurs. The forward direction is preferable to the blowing position of the reducing material.

The position of the tip of the lance is not uniform depending on the blast furnace operating parameters such as the temperature of the blast furnace blast and the amount of oxygen enriched in the blast air. The relative positional relationship is preferably at least the same as shown in the above consideration, or in the order of the gas reducing material, the liquid reducing material, and the solid reducing material in order from the tuyere.
The present invention has been made based on the above findings, and specifically has the following configuration.

(1) A method for injecting a reducing material into a blast furnace according to the present invention includes at least one of a solid reducing material, a liquid reducing material, and a gas reducing material in a blast furnace through a lance provided through a blower pipe of the blast furnace. When two types of reducing materials are blown, a plurality of lances are arranged in the same tuyere, different types of reducing materials are blown from the respective lances, and the tip of at least one lance of the plurality of lances The lance is provided with a curvature so that the extended lines in the blowing direction do not cross each other.

When different types of reducing materials are blown into the blast furnace air duct and tuyere through different blowing lances, by arranging the lances so that the extension lines in the blowing direction do not intersect, It will not interfere with each other.
For this reason, the reducing material with a low combustion rate is deprived of oxygen due to the combustion of the reducing material with a high combustion rate, and does not generate incombustible materials such as “soot” due to incomplete combustion. Will be kept.

(2) Also, when three kinds of reducing materials, that is, a solid reducing material, a liquid reducing material, and a gas reducing material, are blown into the blast furnace through a lance provided through the blast furnace air duct, the same wings are used. Three lances are arranged in the mouth, different kinds of reducing materials are blown from each lance, and the extension line in the blowing direction of the gas reducing material blowing lance, the liquid reducing material blowing lance, and the solid reducing material blowing Each lance is arranged so that it does not cross the extension line in the blowing direction of the insertion lance.

(3) Further, in the above described (1) or (2), the distance between the tuyere tip and the solid reducing material blowing lance tip is L1, and the distance between the tuyere tip and the liquid reducing material blowing lance tip is L2. When the distance between the tip of the tuyere and the tip of the gas reducing material blowing lance is L3, L1, L2, and L3 are in a relationship of L1 ≧ L2 ≧ L3.

(4) Moreover, the reducing material injection device to the blast furnace according to the present invention includes a solid reducing material, a liquid reducing material, and a gas reducing material in the blast furnace through a lance provided through the blast furnace air pipe. A reducing material blowing device for blowing at least two types of reducing materials, wherein a plurality of lances for blowing different reducing materials into the same tuyere are disposed, and the tip of at least one lance of the plurality of lances The plurality of lances are provided with a curvature in the portion so that the extended lines in the blowing direction do not cross each other.

(5) Further, a reducing material blowing device for blowing three kinds of reducing materials, that is, a solid reducing material, a liquid reducing material, and a gas reducing material, into the blast furnace through a lance provided through the blast furnace air duct. There are provided three lances each for blowing different reducing materials into the same tuyere, and these three lances are an extension line of the blowing direction of the gas reducing material blowing lance, a liquid reducing material blowing lance and The solid reducing material blowing lance and the extension line in the blowing direction are arranged so as not to cross each other.

(6) Further, in the above (4) or (5), the distance between the tuyere tip and the solid reducing material blowing lance tip is L1, and the distance between the tuyere tip and the liquid reducing material blowing lance tip is L2. When the distance between the tip of the tuyere and the tip of the gas reducing material blowing lance is L3, L1, L2, and L3 are in a relationship of L1 ≧ L2 ≧ L3.

In the present invention, the same applies when blowing at least two kinds of reducing materials out of a solid reducing material, a liquid reducing material, and a gas reducing material into a blast furnace through a lance provided through a blast furnace air duct. A plurality of lances are arranged at the tuyere of each of the lances, different types of reducing materials are blown from the respective lances, and a curvature is provided at the tip of at least one lance of the lances so that an extension line in the blowing direction Since the lances are arranged so as not to cross each other, the production of unburned material is suppressed, the air permeability of the blast furnace is maintained, and the amount of expensive coke used is reduced by effectively using the blowing reducing material. In addition, the manufacturing cost of pig iron can be reduced.

[Embodiment 1]
FIG. 1 is an explanatory diagram of a blast furnace used in a method for injecting a reducing material into a blast furnace according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of arrangement of lances. Hereinafter, the embodiments of the present invention will be described with reference to FIG.
As shown in FIG. 1, a solid reducing material blowing lance 4, a liquid reducing material blowing lance 5, and a gas reducing material blowing lance 6 are installed through a blower pipe 3 connected to the tuyere 2 of the blast furnace 1. Has been. Although not shown in the figure, the blast furnace 1 has a plurality of tuyere 2, and each tuyere 2 is provided with solid, liquid and gas reducing material blowing lances 4, 5 and 6.

A solid reducing material supply pipe (not shown) is connected to the solid reducing material blowing lance 4, and the solid reducing material supplied from the solid reducing material supply device is sent.
Further, a liquid reducing material supply pipe (not shown) is connected to the liquid reducing material blowing lance 5, and the liquid reducing material supplied from the liquid reducing material supply device is sent.
Further, a gas reducing material supply pipe (not shown) is connected to the gas reducing material blowing lance 6, and the gas reducing material supplied from the gas reducing material supply device is sent.

In this example, methane (CH ₄ ) gas was used as the blowing gas reducing material. Methane gas is the main component of natural gas, and since it is relatively easy to obtain as a gas for blast furnace injection, it was selected as a blowing gas reducing material. However, other gases such as coke oven gas or coal gas are also used. Alternatively, any gas such as city gas or hydrogen gas that enters the blast furnace and acts as a reducing material can be substituted.
Heavy oil was used as the blowing liquid reducing material. In addition, if it is a liquid which enters into a blast furnace and acts as a reducing material, such as tar and naphtha, it can be replaced with heavy oil.
Moreover, pulverized coal was used as the solid reducing material. In this case as well, it can be replaced if it is a solid that enters the blast furnace and acts as a reducing material, such as a synthetic resin material or biomass.

In FIG. 2 showing the arrangement of the lances, FIG. 2 (a) is a view of the tuyere 2, the blower pipe 3, and the various reducing material blowing lances 4, 5, 6 from the rear, and FIG. FIG. 2 (c) is a diagram seen from the side.
As shown in FIG. 2, the liquid reducing material blowing lance 5 and the gas reducing material blowing lance 6 are installed opposite to each other on the horizontal plane, but have a curvature at the tip, and in the blowing direction. The tangential extension lines 5a and 6a do not intersect. The solid reducing material blowing lance 4 does not have a curvature, but its extension line is also arranged so as not to intersect with 5a and 6a.

  The tip positions of the various reducing material blowing lances 4, 5, 6 are arranged in the order of the gas reducing material blowing lance 6, the liquid reducing material blowing lance 5, and the solid reducing material blowing lance 4 from the side closer to the tuyere tip. . More specifically, the distance between the tuyere tip and the solid reducing material blowing lance tip is L1, the distance between the tuyere tip and the liquid reducing material blowing lance tip is L2, and the distance between the tuyere tip and the gas reducing material blowing lance tip. When the distance is L3, L1 = 60 mm, L2 = 50 mm, and L3 = 40 mm.

In the present embodiment configured as described above, the gas reducing material, the liquid reducing material, and the solid reducing material are combustible when they are blown into the blast furnace air duct and tuyere through different blowing lances. Since the inferior position of the inferior solid reductant is located behind the tip of the tuyere, a long residence time in the high-temperature region before being fed into the furnace can be secured, and complete combustion occurs when fed into the furnace. It has become easier.
Therefore, even if it is supplied into the furnace, it cannot be burned completely, and it is less likely to remain as unburned material, and deterioration of air permeability due to remaining unburned material can be prevented.

In addition, by setting the distance L3 between the tuyere tip and the gas reducing material blowing lance tip to 40 mm, the combustion of the gas reducing material up to the two stages described above is suppressed as much as possible before CO ₂ and H ₂ O are generated. In addition, the one-stage combustion gas shown in Equation 3 above can be supplied to the combustion zone inside the blast furnace where coke is present, suppressing the deterioration of coke caused by CO ₂ and H ₂ O, and reducing the coke pulverization. It is possible to suppress the deterioration of air permeability due to coke powdering.
As for the liquid reducing material, the distance between the tuyere tip and the liquid reducing material blowing lance tip is set to L2 = 50 mm, so the same thing as the above gas reducing material can be said. Can be prevented.

  In the present embodiment, since the lances are arranged so that the extension lines in the blowing direction of the blowing lances of the reducing materials do not intersect, the flow paths when the reducing materials are blown are overlapped. No longer. For this reason, for example, when the solid reducing material is blown into the region where oxygen is insufficient due to the combustion of the gas reducing material, the solid reducing material is not burned incompletely to generate unburned material such as “soot”, Accordingly, it is possible to prevent deterioration of air permeability due to remaining unburned material.

  As described above, according to the present embodiment, deterioration of air permeability in the furnace is prevented, so that a plurality of reducing materials can be stably blown, and as a result, the coke ratio is reduced. be able to.

In FIG. 2 showing the above embodiment, three cases are illustrated. However, in the present invention, it is assumed that at least two kinds of reducing materials are used. When using a liquid reducing material, the case where the solid reducing material blowing lance 4 is removed may be considered. Similarly, when the gas reducing material and the solid reducing material are used, or when the liquid reducing material and the solid reducing material are used, the case where the lance for blowing the reducing material that is not used is removed may be considered.
The relative distance from the tip of the tuyere of the solid reducing material blowing lance 4, the liquid reducing material blowing lance 5, and the gas reducing material blowing lance 6 is also as shown in the above embodiment. However, the present invention is not limited to the case where the solid reducing material blowing lance 4, the liquid reducing material blowing lance 5, and the gas reducing material blowing lance 6 are arranged in order from the tip of the tuyere.
Then, regarding the arrangement | positioning of various reducing material blowing lances, a modification is shown as another embodiment below.

[Embodiment 2]
FIG. 3 is an explanatory view of the reducing material blowing device according to Embodiment 2 of the present invention, and the same parts as those in FIG.
As shown in FIG. 3, the reducing material blowing device according to the present embodiment adjusts the lance position so that the extended lines in the blowing direction of each lance do not intersect with each other, and sets the blowing position of each lance to the tuyere All are adjusted to the same position (L1 = L2 = L3 = 50 mm) from the tip.

In the present embodiment, since the extended lines in the blowing direction of the respective lances do not intersect, the solid reducing material is blown into the region where oxygen is insufficient due to the combustion of the gas reducing material, for example, as in the first embodiment. As a result, the solid reducing material does not burn incompletely to generate unburned material such as “soot”, and the effect of preventing the deterioration of air permeability due to the remaining unburned material can be obtained.
Further, since the blowing positions of the lances are all adjusted to a position relatively close to the tuyere tip of 50 mm from the tuyere tip, it is possible to prevent deterioration of air permeability due to coke pulverization as in the first embodiment. The effect is also obtained.

[Embodiment 3]
FIG. 4 is an explanatory view of a reducing material blowing device according to Embodiment 3 of the present invention, and the same parts as those in FIG.
The reducing material blowing device according to the present embodiment blows two kinds of reducing materials, that is, a solid reducing material and a gaseous reducing material. Specifically, as shown in FIG. 4, from the one shown in FIG. In this case, the liquid blowing lance 5 which is unnecessary is removed. In other words, the lance position is adjusted so that the extension line in the blowing direction of the solid reducing material blowing lance 4 and the gas reducing material blowing lance 6 does not intersect, and the blowing position L1 of the solid reducing material blowing lance 4 is set to the wing position. The blowing position L3 of the gas reducing material blowing lance 6 is 40 mm from the tip of the tuyere.

  In the case of this example, the only difference from the first embodiment is that there are two types of reducing materials to be blown in, so the same effect as in the first embodiment can be obtained.

[Embodiment 4]
FIG. 5 is an explanatory view of a reducing material blowing device according to Embodiment 4 of the present invention, and the same parts as those in FIG.
The reducing material blowing device according to the present embodiment is for blowing three kinds of reducing materials as in the first embodiment, and as shown in FIG. 5, an extension line in the blowing direction of each lance. Are not intersecting and the blowing position is L1 <L2 <L3. Specific positions are L1 = 30 mm, L2 = 40 mm, and L3 = 50 mm.

Also in the present embodiment, as in the above-described second embodiment, the extension lines in the blowing direction of the lances do not intersect. For example, the solid reducing material is blown into a region where oxygen is insufficient due to combustion of the gas reducing material, for example. As a result, the solid reducing material does not burn incompletely to generate unburned material such as “soot”, and the effect of preventing the deterioration of air permeability due to the remaining unburned material can be obtained.
Further, since the blowing positions of the lances are all adjusted to a position relatively close to the tuyere tip of 50 mm from the tuyere tip, it is possible to prevent deterioration of air permeability due to coke pulverization as in the first embodiment. The effect is also obtained.

[Embodiment 5]
FIG. 6 is an explanatory view of a reducing material blowing device according to Embodiment 5 of the present invention, and the same parts as those in FIG.
The reducing material blowing apparatus according to the present embodiment relates to an apparatus for blowing two kinds of reducing materials, that is, a solid reducing material and a gaseous reducing material, as in the third embodiment. Specifically, as shown in FIG. 6, the liquid blowing lance 5 which is unnecessary in this case is removed from that of FIG. 5 showing the fourth embodiment. In other words, the lance position is adjusted so that the extension line in the blowing direction of the solid reducing material blowing lance 4 and the gas reducing material blowing lance 6 does not intersect, and the blowing position L1 of the solid reducing material blowing lance 4 is set to the wing position. The blowing position L2 of the gas reducing material blowing lance 6 is set to 30 mm from the tip of the mouth, and 50 mm from the tip of the tuyere.

  In the case of this example, the only difference from the fourth embodiment is that there are two types of reducing materials to be blown in, so the same effect as in the fourth embodiment can be obtained.

  In the above embodiment, when three types of reducing materials are blown, the lance position is adjusted so that the extension lines in the blowing direction of the blowing lances for blowing the reducing materials do not intersect. Since the reducing material has the highest combustibility, it is arranged so that at least the extension line in the blowing direction of the gas reducing material blowing lance does not intersect the extending line in the blowing direction of the other two blowing lances, A certain effect can be obtained.

In order to demonstrate the effect of the present embodiment, blast furnace operation was performed using the reducing material blowing device.
The composition of the blown reducing material used is shown in Table 1. As described above, methane gas was used as the gas reducing material, heavy oil was used as the liquid reducing material, and pulverized coal was used as the solid reducing material.

  Table 2 shows the amount of each reducing material blown. As shown in Table 2, the total blowing amount was 200 kg / t-p, and the blowing amount of each reducing material was blown in two cases of A and B.

Table 3 shows the results of blast furnace operation including the placement of lances.

In addition, in the Example of Table 3, and the comparative example, the change of the blast furnace coke usage-amount (coke ratio) in the ventilation pressure constant is described. The reason for this is as follows.
The blast pressure largely depends on the production volume and the air permeability in the furnace. When the production amount is increased, the amount of reducing gas is increased, so that the gas flow rate in the blast furnace is increased and the blowing pressure is increased.
Also, as mentioned above, if the amount of unburned blown reducing material and coke pulverization at the tuyere increases, the air permeability in the blast furnace deteriorates and the blowing pressure increases and the amount of coke used increases. If it does, air permeability in a blast furnace will improve and ventilation pressure will fall.

In general, the production amount is determined by a contract with a customer or the like, and it is desirable to keep it constant for a specific period. Therefore, reducing the coke ratio under the condition of constant production volume until the blowing pressure reaches the upper limit is important for reducing the production cost.
In the blast furnace of this example, the maximum blowing pressure is 0.38 MPa in terms of equipment capacity. Therefore, in this example, the blast pressure is set to a maximum of 0.38 MPa, and the evaluation is made by paying attention to the lower limit of the coke ratio under various reducing material blowing conditions.
Hereinafter, Examples 1 to 5 and Comparative Examples 1 and 2 shown in Table 3 will be considered.

Example 1 shows an operation example in which various reducing materials were blown from the tuyere under the blowing condition A shown in Table 2 using the blowing lance described in the present invention. The arrangement A shown in the lower part of Table 3 is as shown in FIG. 2, and each lance does not intersect with the extension line of the blowing direction, and the blowing position is the gas reducing material and the liquid in order from the tip of the tuyere. It is a reducing material and a solid reducing material. More specifically, the distance between the tuyere tip and the solid reducing material blowing lance tip is L1, the distance between the tuyere tip and the liquid reducing material blowing lance tip is L2, and the distance between the tuyere tip and the gas reducing material blowing lance tip. When the distance is L3, L1 = 60 mm, L2 = 50 mm, and L3 = 40 mm.
In this case, stable operation could be continued and the coke ratio was about 300 kg / tp.

Example 2 shows an operation example in which various reducing materials were blown from the tuyere under the blowing condition A shown in Table 2 using the blowing lance described in the present invention. As shown in Fig. 3, the position B shown in the lower part of Table 3 is to adjust the lance position so that the extended lines in the blowing direction of each lance do not intersect, and to set the blowing position of each lance from the tip of the tuyere All are adjusted to the same position (50mm).
In this case, stable operation could be continued and the coke ratio was about 300 kg / tp as in Example 1.

Example 3 shows an operation example in which various reducing materials were blown from the tuyere under the blowing condition B shown in Table 2 using the blowing lance described in the present invention. As shown in FIG. 4, the arrangement C shown in the lower part of Table 3 is obtained by removing the liquid blowing lance 5 which is unnecessary in this case from the one shown in FIG. The blowing position of the solid reducing material blowing lance 4 is 60 mm from the tip of the tuyere, and the blowing position of the gas reducing material blowing lance 6 is 40 mm from the tip of the tuyere.
In this case, stable operation could be continued, and the coke ratio was about 300 kg / tp as in Example 1 and Example 2.

Example 4 shows blast furnace operation results when the blowing method described in the present invention is employed. Various reducing materials were blown from the tuyere under blowing condition A, and arrangement D was adopted as shown in the lower part of Table 3. The arrangement D is a case where the extension lines in the blowing direction of the lances do not intersect as shown in FIG. 5 and the blowing position is L1 <L2 <L3. Note that L1 = 30 mm, L2 = 40 mm, and L3 = 50 mm.
The coke ratio was about 315 kg / tp, which was slightly higher than those in Examples 1 to 3, but stable operation was possible.

Example 5 shows the blast furnace operation results when the blowing method described in the present invention is employed. Various reducing materials were blown from the tuyere under blowing condition B, and arrangement E was adopted as shown in the lower part of Table 3. As shown in FIG. 6, the arrangement E is a case where the extension lines in the blowing direction of the lances do not intersect and the blowing position is L1 <L3. Note that L1 = 30 mm and L3 = 50 mm.
The coke ratio was about 315 kg / tp, which was slightly higher than those in Examples 1 to 3, but stable operation was possible.

  The comparative example 1 has shown the blast furnace operation result at the time of not employ | adopting the blowing method as described in this invention. Various reducing materials were blown from the tuyere under blowing condition A, and arrangement F was adopted as shown in the lower part of Table 3. As shown in FIG. 7, the arrangement F is a case where the extension lines in the blowing direction of the lances intersect each other at one point. The blowing position of each lance is adjusted to the same position (50 mm) from the tip of the tuyere.

  In this case, accumulation of unburned material of the blown reducing material into the blast furnace and accumulation of coke powder tended to increase air permeability. Therefore, as a result of increasing the amount of coke used as needed (to reduce the blowing pressure), the coke ratio is about 350 kg / tp, which is higher than in Examples 1 to 3, and the hot metal production cost Rose.

  The comparative example 2 has shown the blast furnace operation result at the time of not employ | adopting the blowing method as described in this invention. In this example, two types of reducing materials, a solid reducing material and a gas reducing material, were blown from the tuyere under the blowing condition B, and the arrangement G of the lance was adopted as shown in the lower part of Table 3. As shown in FIG. 8, the arrangement G is an arrangement in which the liquid reducing material blowing lance 5 is removed from the arrangement shown in FIG. 7, and the extended lines in the blowing direction of the two lances intersect each other. . The blowing position of each lance is adjusted to the same position (50 mm) from the tip of the tuyere.

  In this case, accumulation of unburned material of the blown reducing material into the blast furnace and accumulation of coke powder tended to increase air permeability. For this reason, as a result of increasing the amount of coke used as needed (to reduce the blowing pressure), the coke ratio is about 360 kg / tp, which is higher than in Examples 1 to 3, and hot metal production Cost increased.

As described above, in Examples 1 to 5 within the scope of the present invention, the coke ratio was 301 kg / tp to 316 kg / tp, a low coke ratio was achieved, and stable operation could be continued.
On the other hand, in Comparative Examples 1 and 2 in which the present invention was not adopted, the coke ratio was as high as 350 or more, and the operation was unstable.
From the above, it was proved that the adoption of the present invention enables the realization of a low coke ratio and the stable operation to be continued.

It is explanatory drawing of the blast furnace used for the reducing material blowing method which concerns on one Embodiment of this invention. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on Embodiment 2 of this invention. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on Embodiment 3 of this invention. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on Embodiment 4 of this invention. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on Embodiment 5 of this invention. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on a comparative example. It is explanatory drawing of the principal part of the reducing material blowing apparatus which concerns on a comparative example.

Explanation of symbols

    1 Blast furnace, 2 tuyere, 3 air pipes, 4 solid reducing material blowing lance, 5 liquid reducing material blowing lance, 6 gas reducing material blowing lance.

Claims (6)

In the case where at least two kinds of reducing materials among the solid reducing material, liquid reducing material, and gas reducing material are blown into the blast furnace through a lance provided through the blast furnace air duct, a plurality of the same tuyere are used. Lances are provided, different types of reducing materials are blown from each lance, and a curvature is provided at the tip of at least one lance of the plurality of lances so that the extension lines in the blowing direction do not cross each other. A method for injecting a reducing material into a blast furnace, characterized by disposing a lance.   When three types of reducing materials, solid reducing material, liquid reducing material, and gas reducing material, are blown into the blast furnace through a lance provided through the blast furnace air duct, three lances are inserted into the same tuyere. The different reducing materials are blown from the respective lances, and the extension line of the blowing direction of the gas reducing material blowing lance and the blowing direction of the liquid reducing material blowing lance and the solid reducing material blowing lance A method for injecting a reducing material into a blast furnace, characterized in that each lance is disposed so as not to intersect with an extension line of the blast furnace.   When the distance between the tuyere tip and the solid reducing material blowing lance tip is L1, the distance between the tuyere tip and the liquid reducing material blowing lance tip is L2, and the distance between the tuyere tip and the gas reducing material blowing lance tip is L3 Further, L1, L2, and L3 are in a relationship of L1 ≧ L2 ≧ L3, and the method of injecting the reducing material into the blast furnace according to claim 1 or 2. A reducing material blowing device that blows at least two kinds of reducing materials out of a solid reducing material, a liquid reducing material, and a gaseous reducing material into a blast furnace through a lance provided through a blow pipe of the blast furnace,
A plurality of lances for blowing different reducing materials into the same tuyere are provided, and a curvature is provided at the tip of at least one lance of the plurality of lances. A device for blowing a reducing material into a blast furnace, which is arranged so as not to cross each other.   A reducing material blowing device for blowing three kinds of reducing materials, a solid reducing material, a liquid reducing material, and a gas reducing material, into a blast furnace through a lance provided through a blow pipe of the blast furnace. Three lances for blowing different reducing materials into the tuyere are arranged, and these three lances are extended lines in the blowing direction of the gas reducing material blowing lance, the liquid reducing material blowing lance and the solid reducing material blowing. An apparatus for injecting a reducing material into a blast furnace, wherein the lance and an extension line in the blowing direction do not cross each other. When the distance between the tuyere tip and the solid reducing material blowing lance tip is L1, the distance between the tuyere tip and the liquid reducing material blowing lance tip is L2, and the distance between the tuyere tip and the gas reducing material blowing lance tip is L3 Furthermore, L1, L2, and L3 are in a relationship of L1 ≧ L2 ≧ L3, The reducing material injecting device to a blast furnace according to claim 4 or 5,

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