JPH0657315A - Operation of blast furnace based on hydrogen gas utilizing ratio - Google Patents

Abstract

PURPOSE:To make the length of a low temp. region proper and to improve the utilizing ratio of reducing gas by measuring furnace gas composition at plural points in the radius direction of a blast furnace, calculating a hydrogen gas utilizing ratio and adjusting the distribution of charged materials at the furnace top based on the calculation. CONSTITUTION:By using sondes 8, 9 at plural positions in the height direction of a bulky zone part 6 in the blast furnace shaft part, the composition and the quantity of the furnace gas are measured and the hydrogen gas utilizing ratio is calculated based on these measured values. By obtaining the difference between these hydrogen gas utilizing ratios and based on the difference, the distribution of the charged materials at the furnace top is adjusted to improve the gas ventilation. By this method, the length of low temp. region in the blast furnace is kept so as to be suitable and the stabilized operation can be continued.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace operating method using the hydrogen gas utilization rate of a blast furnace shaft.

[0002]

2. Description of the Related Art In blast furnace operation, optimizing the temperature distribution in the lump furnace zone in the blast furnace, especially the length of the low temperature region of 500 to 800 ° C. in the height direction of the lump furnace zone Is very important in stabilizing the fuel and improving the reducing gas utilization rate and reducing the fuel ratio. That is, 500 to 8
The low temperature region of 00 ° C is the temperature region where the reduction and pulverization of the iron source such as the sinter or lump ore charged in the furnace is most likely to occur. The longer the low temperature region, the more the reduction and pulverization is promoted. Since the air permeability in the blast furnace is deteriorated and the furnace condition is poor, it is necessary to detect the length of the low temperature region and optimize the length. Therefore, conventionally, as a method for detecting the low temperature region in the massive band portion, for example, there is a method for obtaining from the temperature distribution in the furnace height direction directly measured by a vertical sonde. Measurement of temperature distribution using this vertical probe requires a large amount of equipment, which requires a large amount of capital investment, operating costs, and labor costs.
Furthermore, since it takes several hours for one measurement, it is practically difficult to use it for daily blast furnace operation management.

Therefore, in order to use it for daily blast furnace operation management, the present inventors did not directly measure the temperature distribution in the furnace height direction in the past, but based on the hydrogen gas utilization rate in the furnace, the above-mentioned 500- A method for estimating the length of the low temperature region of 800 ° C was proposed. This is a reaction simulator in a blast furnace proposed in Japanese Utility Model Publication No. 1-27038 (a furnace core tube in which ore is filled from the upper part and reducing gas is conducted from the lower part, and the reducing gas and the ore are countercurrently contacted, (A device having a heater surrounding a part of the furnace core tube and movably provided in the reducing gas downstream direction), that is, a low temperature region of 500 to 800 ° C. in the packed bed height direction The phenomenon that the hydrogen gas utilization rate ηH ₂ decreases as the temperature becomes longer, is disclosed in Japanese Patent Publication No. 63-61366.
There is a proposal in Japanese Examined Patent Publication No. 3-27604.

Japanese Patent Publication No. 63-61366 discloses a method of estimating the low temperature region of the massive zone by analyzing the blast furnace gas composition at the top of the blast furnace and calculating the hydrogen gas utilization rate. According to Japanese Examined Patent Publication No. 3-27604, a sonde is inserted from the upper part of the shaft portion of the blast furnace to analyze the gas composition in the furnace at a plurality of points in the lump furnace zone in the radial direction of the blast furnace, and the hydrogen gas utilization rate or the hydrogen gas utilization rate / CO This is a method of estimating the low temperature region in the blast furnace height direction at each of the above measurement points by calculating the gas utilization rate.

[0005]

[Problems to be Solved by the Invention]
In the method proposed in Japanese Patent Application No. 3-61366, since the above-described furnace top hydrogen gas utilization rate is an index of the entire blast furnace, it is not possible to detect that an abnormal portion of the length of the low temperature region exists at any position in the furnace. It is possible, but the part cannot be specified. Further, in the method proposed in Japanese Examined Patent Publication No. 3-27604, since the hydrogen gas utilization rate in the blast furnace radial direction at a specific height position is used as an index, the change of the hydrogen gas utilization rate in the region below the massive zone is changed. Inevitably caused by disturbance. Therefore, it is difficult to determine whether the decrease in the hydrogen gas utilization rate is caused by the lump zone portion or the lower portion of the lump zone.

According to the present invention, the length of the low temperature region of 500 to 800 ° C. in the lump furnace zone is abnormal by accurately estimating the site where the hydrogen gas utilization rate is reduced in the lump furnace zone. It is an object to optimize the length of the low temperature region by finding a certain part and adjusting the distribution of the top charge, stabilizing the blast furnace operation, improving the reducing gas utilization rate and reducing the fuel ratio. Is.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the means is to provide a radial direction of a blast furnace at each of a plurality of predetermined positions in the height direction of a lump zone portion of a blast furnace shaft. In the furnace, the composition and amount of the gas in the furnace are measured at a plurality of predetermined locations, and the hydrogen gas utilization rate is calculated based on the measured values, and the hydrogen gas utilization between the predetermined positions in the height direction of the massive zone is performed. This is a blast furnace operating method in which the difference in the rate is obtained, and the distribution of the top charge is adjusted based on the difference in the hydrogen gas utilization rate to maintain the difference within a predetermined range.

The distribution of the charged material in the radial direction of the blast furnace is adjusted by a known method, for example, the adjustment of the armor plate in the bell type blast furnace and the adjustment of the turning speed of the turning chute in the bellless blast furnace are most effective. However, in addition to the above, the property of the charged material, the amount of the charged material, and the like may be changed individually or in combination. or,
Calculation of hydrogen gas utilization rate is given by the following formula (1) or special fair 3
H ₂ O using the water concentration and hydrogen concentration measured by each shaft probe 8 and 9 as described in JP-A-27604.
% / Or may be calculated by _{(H 2% + H 2 O} %) , but the present invention is not limited thereto, may be any calculation method known manner.

100− (100− furnace top hydrogen gas utilization rate) × (hydrogen concentration at each part) / (hydrogen concentration in furnace top gas) [%] (1) where (a) furnace top hydrogen gas The utilization rate is a value calculated by (amount of supplied hydrogen-hydrogen concentration in furnace top gas) × 100 / amount of supplied hydrogen [%]. (B) Furnace top hydrogen gas utilization rate is the gas analyzer 1 installed at the furnace top
It is the hydrogen concentration in the furnace top gas measured at 0. (C) The amount of hydrogen supplied is the total amount of hydrogen supplied to the blast furnaces, such as the amount of hydrogen in the charge, the amount of hydrogen in the hot air blown from the tuyere, and the amount of hydrogen in the pulverized coal.

[0010]

The operation of the present invention will be described with reference to FIGS. 500 to 800 in the height direction of the blast furnace measured using the rigid vertical probe 7 installed in the actual blast furnace shown in FIG.
° C region length, and a sonde inserted from the upper part of the shaft corresponding to the upper part of the massive band 6 (hereinafter simply referred to as the upper shaft sonde) 8 and a sonde inserted from the middle part of the shaft corresponding to the lower part of the massive band 6 (hereinafter simply referred to as the central shaft sonde). 9) between the position of the central sonde of the shaft and the position of the upper sonde of the shaft obtained from the gas composition in the furnace measured using (9) ((hydrogen partial pressure PH ₂ × carbon dioxide partial pressure PCO ₂ ) / (water partial pressure PH ₂ O × The relationship of carbon monoxide partial pressure PCO)} is shown in FIG. This figure shows a water-gas shift reaction in which water in the furnace gas reacts with carbon monoxide as the low temperature region of 500 ° C. to 800 ° C. develops and becomes longer in the blast furnace height direction, that is, in the furnace gas flow direction. H ₂ O + CO = CO ₂ + H ₂ ) is progressing. Then, as the water gas shift reaction proceeds, the hydrogen concentration in the blast furnace gas gradually increases and the hydrogen gas utilization rate decreases.

Therefore, according to the present invention, the composition of the gas in the furnace is measured, the hydrogen gas utilization rate in the lump zone is calculated based on the composition, and the calculated hydrogen gas utilization rate is set as the previously determined target. By comparing with a predetermined range value, the abnormality of the low temperature region length of 500 to 800 ° C. (whether it is within the reference length range) is determined. As a means for estimating the temperature distribution in the blast furnace height direction in this massive zone, the hydrogen gas utilization rate at multiple positions in the blast furnace radial direction was measured using two types of sondes 8 and 9 installed in the upper and middle parts of the blast furnace shaft. It is possible to improve the estimation accuracy by determining the difference by excluding the disturbance due to the fluctuation of the hydrogen gas utilization rate below the sonde 9. That is, FIG. 3 shows an example in which the hydrogen gas utilization ratio ηH _2-8 was measured at seven points in the blast furnace radial direction by the blast furnace shaft upper sonde 8. Considering only the hydrogen gas utilization rate ItaH _2-8 in the upper probe position in the drawing, (Distance / blast radius to the measuring position from the furnace center) 0 lowest site of the hydrogen gas utilization rate ItaH _2-8 dimensionless radius It is around 0.4.

However, this may include the influence of the cohesive zone or the lower part thereof as described above, and in order to eliminate this, the sonde 9 is inserted from the center of the shaft,
The in-furnace gas composition at seven points in the dimensionless radius of 0.4 to 1.0 at the center of the shaft was measured, and the hydrogen gas utilization rate ηH _2-9 was determined based on this measurement, which is shown in FIG. . Then, between predetermined positions corresponding to the gas flow in the furnace, that is,
Difference with hydrogen gas utilization at the same dimensionless radial position (ηH _2-9
−ηH _2-8 = ΔH _2a ), that is, the result of calculating the hydrogen gas utilization rate in the massive zone between the sondes 8 and 9 is shown in FIG. In addition, the hydrogen gas utilization rate ηH at the central position of this shaft
_The position where the difference between the hydrogen gas utilization ratio ηH _2-9 between _2-8 and the upper shaft position is determined to be the same dimensionless radial position is measured in the middle position of the shaft in the furnace gas rising from the lower furnace. This is because the same gas as the gas in the furnace is measured at the upper position of the shaft.

As shown in FIG. 3, the hydrogen gas utilization difference ΔηH ₂ between the central sonde position and the upper sonde position is the largest in the blast furnace radial direction in the lump zone, that is, there is no region where the hydrogen gas utilization ratio is the lowest. It can be determined that the dimension radius is around 0.6. As described above, even when the hydrogen gas utilization rate judged only by the upper shaft sonde 8 includes the disturbance in the lower portion of the furnace (cohesive zone or below), the hydrogen gas utilization rate detected by the central shaft sonde 9 By obtaining the difference, it is possible to accurately determine the hydrogen gas utilization rate in the massive zone.

Thus, the difference ΔηH ₂ in the hydrogen gas utilization rate obtained as described above is compared with a predetermined range value, and the difference Δη in the hydrogen gas utilization rate at any part in the radial direction of the blast furnace is compared.
When H ₂ is out of the control value, that is, when the low temperature region of 500 to 800 ° C. is longer than a predetermined length, the air permeability of the part deteriorates. By improving the temperature distribution in the radial direction of the blast furnace, the length of the low temperature region is prevented from exceeding a predetermined length. By performing such an operation action, the length of the low temperature region in the blast furnace is properly maintained and stable operation is continued. The predetermined range of the hydrogen gas utilization difference ΔηH ₂ varies depending on the target blast furnace, the quality of the sinter and the operating conditions, and is thus obtained by an operating test in advance.

[0015]

Next, an embodiment of the present invention will be described in detail with reference to FIGS. In FIG. 1, 1 is a large bell, 2 is a charge on the large bell, 4 is an armor plate, 5 is an ore receiver provided on the side wall of the blast furnace, 6 is a massive band of the charge accumulated in the furnace, Reference numeral 8 is an upper sonde provided 4.5 m below the stock line of the charge, and 9 is a central sonde provided immediately adjacent to the cohesive zone 3 and 7 m below the upper sonde 8. And this blast furnace has an internal volume of 5245 m ³ and an air flow of 8100 Nm.
³ / min, blast humidity: 41 g / Nm ³ , oxygen addition: 15
000Nm ³ / hour, differential coal injection rate: 80kg / t-pig,
Amount of tapping: 12000 tons / day, charging mode of charging: C
(Coke) C (coke) O (ore) O (ore). Further, the target predetermined range value of the difference in hydrogen gas utilization rate of the blast furnace is -5% or more, which is a value obtained by analyzing past operation data and the like.

Example 1 The mode of the armor plate 4 is set to (0000) <the above-mentioned charging
Armor plate corresponding to CCOO in charging mode
It is a value that indicates the number of each notch of 4, and the value increases
About this, the falling position of the charge kicked and charged is in the furnace
Being closer to your heart> When the blast furnace is operating, the furnace conditions become unstable
became. Upper sonde 8 and gas analyzer 1 in this state
Hydrogen gas utilization ratio η obtained by measuring at 0
H_2-8, Measured by the central sonde 9 and gas analyzer 10
Hydrogen gas utilization rate in the radial direction ηH_2-9Is shown in Fig. 3.
Difference (ηH_2-9-ΗH_2-8= ΔηH_2a) Is shown in FIG.
As can be seen from FIG. 4, the hydrogen gas utilization rate ΔηH _2a
Has the smallest dimensionless radius around 0.6, and its value is −
16%, a predetermined range value ηH of the difference in hydrogen gas utilization rate₂₀(-
5% or more) outside. For this reason, the armor plate 4
Use mode for both (1204) and (0009)
2: 1) and then kick coke and ore into the center of the furnace.
Promoted the amount.

As a result, the ore / coke in the middle part of the furnace, which has a dimensionless radius of about 0.6, is relatively lowered to improve the air permeability, and the effect of improving the air permeability appears. Hydrogen concentration in the blast furnace gas was measured with the gas analyzer 10, and the hydrogen gas utilization rate η calculated by the above equation (1) was calculated.
H _2-9, the hydrogen concentration measured in the blast furnace gas at the top sonde 8 and the gas analyzer 10, the (1) the difference between the hydrogen gas utilization rate ItaH _2-8 measured calculated by equation (ηH _{2- 9} -ηH _{2 -8} = ΔηH _2b )
Is around -4% around a dimensionless radius of 0.6, within the above specified range value ηH ₀₂ (-5% or more), the furnace condition is stable, and the fuel ratio is changed from 498 kg / t-pig to 487 kg / t-pig. Reduced.

Embodiment 2 The modes of the armor plate 4 are (1204) and (000
When operating for a long time while using 9) together (the degree of use was 2: 1), the reactor conditions were becoming unstable again. In this state, the hydrogen gas utilization ratio η in the furnace radial direction obtained by measuring the hydrogen concentration in the blast furnace gas with the upper sonde 8 and the gas analyzer 10
H _2-8 , hydrogen gas utilization rate ηH in the furnace radial direction obtained by measuring the hydrogen concentration in the blast furnace gas with a central sonde 9 gas analyzer 10
_2-9 are shown in FIG. 5, and the difference (ηH _2-9 −ηH _2-8 =
Δη H _2c ) is shown in FIG. As you can see from this Figure 6,
The difference in hydrogen gas utilization rate ΔηH _c is the smallest in the vicinity of the dimensionless radius of 0.4, and the value is -8%, outside the predetermined range value ηH ₀₂ (-5% or more) of the difference in hydrogen gas utilization rate. is there. For this reason, the usage mode of the armor plate 4 was used in combination with (2406) and (00011) (the degree of usage was 2: 1) to promote the amount of coke and ore kicked into the center of the furnace.

As a result, the ore / coke in the middle part of the furnace, which has a dimensionless radius of about 0.4, is further lowered relatively to improve the air permeability, and the effect of improving the air flow appears. And the gas analyzer 10 were used to measure the hydrogen concentration in the blast furnace gas, and the hydrogen gas utilization rate η calculated by the above equation (1) was calculated.
H _2-9 , the upper sonde 8 and the gas analyzer 10 were used to measure the hydrogen concentration in the blast furnace gas, and the hydrogen gas utilization rate η H _2-8 calculated by the above equation (1) was as shown in FIG. 7. Difference (ηH
_2-9 −ηH _2-8 = ΔηH _2d ) is shown in FIG. From FIG. 6, the difference in hydrogen gas utilization rate ΔηH _2d is 0 to -4%, which is within the predetermined range value ηH ₂₀ (-5% or more), the furnace condition is stable, and the fuel ratio is 487 kg / t-pig to 483 kg / It could be reduced to t-pig.

In this embodiment, the upper and middle parts of the blast furnace shaft are
Insert the sondes 8 and 9 into each part and measure the gas composition in the furnace
However, the present invention is not limited to this.
Between the upper upper sonde 8 and the shaft middle sonde 9
Insert the intermediate sonde into the middle of the shaft upper sonde 8
Sonde, Shaft Intermediate Sonde 9 and Intermediate Sonde
Then, the difference in hydrogen gas utilization is calculated in the same manner as above,
Length of low temperature zone from 500 to 800 ° C in 2 to massive zones
Is preferable because the estimation accuracy is improved. or,
In the above embodiment, the difference in hydrogen gas utilization rate ΔηH₂To
[ΗH_2-9-ΗH_2-8] As the goal
Predetermined range value ηH₂₀Was set to -5% or more, but the present invention
The hydrogen gas utilization rate difference ΔηH is not limited to₂(Η
H_2-8-ΗH_2-9], But this
In the above case, the predetermined range value ηH ₂₀Is -5% or less
It

[0021]

EFFECTS OF THE INVENTION According to the present invention, 5 is formed in a lumpy band portion.
The length of the low temperature region of 00 to 800 ° C. is accurately estimated, and an abnormally long length is prevented by adjusting the distribution of the charge to be charged into the blast furnaces. The length can be properly maintained, and the blast furnace operation can be continuously performed with a low fuel ratio, which is a great effect.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a blast furnace for carrying out the present invention,

FIG. 2 shows the relationship between {(hydrogen partial pressure PH ₂ × carbon dioxide partial pressure PCO ₂ ) / (water partial pressure PH ₂ O × carbon monoxide partial pressure PCO)} and the length of the 500 to 800 ° C. region in the massive zone. Figure showing,

FIG. 3 is a diagram showing a relationship between a dimensionless radius of a blast furnace and a hydrogen gas utilization rate,

FIG. 4 is a diagram showing a relationship between a dimensionless radius of a blast furnace and a difference between hydrogen gas utilization rates;

FIG. 5 is a diagram showing a relationship between a dimensionless radius and a hydrogen gas utilization rate according to another embodiment of a blast furnace,

FIG. 6 is a diagram showing the relationship between the dimensionless radius and the difference in hydrogen gas utilization rate according to another embodiment of the blast furnace;

FIG. 7 is a diagram showing a relationship between a dimensionless radius and a hydrogen gas utilization rate according to still another embodiment of a blast furnace.

[Explanation of symbols]

 1 Large Bell 2 Charge on Large Bell 3 Cohesive Zone 4 Armor Plate 5 Ore Receiving Metal 6 Bulk Zone 7 Rigid Vertical Sonde 8 Upper Sonde 9 Middle Sonde 10 Gas Analyzer

Front Page Continuation (72) Inventor Seisho Naito 20-1 Shintomi, Futtsu City, Chiba Shin Nippon Steel Co., Ltd.

Claims (1)

[Claims] 1. At each of a plurality of predetermined locations in the height direction of the lump furnace zone of the blast furnace shaft, the components and amounts of the gas in the furnace are measured at a plurality of predetermined locations in the radial direction of the blast furnace, and based on the measured values. The hydrogen gas utilization rate is calculated, and the difference in the hydrogen gas utilization rate between the predetermined positions in the height direction of the massive zone is obtained, and the distribution of the top charge is adjusted based on the difference in the hydrogen gas utilization rate. A method of operating a blast furnace using hydrogen gas utilization, characterized in that the difference is maintained within a predetermined range.