JPS6022042B2 - Method for detecting circumferential distribution deviation in blast furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for quantitatively detecting circumferential deviations of flow in a blast furnace.

The recent trend toward energy conservation efforts has become significantly stronger in blast furnaces as well, and stabilization of blast furnace operations and energy conservation (low fuel ratio) have been promoted in tandem.

In this process, particular emphasis was placed on controlling the distribution of flow in the radial direction within the blast furnace, which forms the body of the cylindrical container, and as a result, controlling the distribution in the radial direction contributes most significantly to energy conservation in the blast furnace. In the current situation. In order to further advance energy conservation from this stage, it is necessary to control the distribution of physical flow in the circumferential direction within the furnace. For example, if there are differences in the composition and temperature of hot metal and melt discharged from multiple outlets arranged in the circumferential direction, it is necessary to manage operations according to the lower side of the furnace heating bell, and the difference is large. In some cases, energy-saving (low fuel ratio) operation cannot be carried out successfully. Additionally, there is no method for quantitatively expressing deviations in the flow distribution in the circumferential direction within the furnace, and only qualitative judgments have been made mainly by the following detection means.

'11 The readings of the thermometers installed on the wall of the blast furnace or in the circumferential direction inside the furnace differ even if they are at the same level, and this difference also changes over time.

'21 In a blast furnace that has multiple tap ports in the circumferential direction of the blast furnace, if you take the average values over a certain period of time, you will find significant deviations in the components and temperatures between each tap port.

However, with the above two detection means, although it is recognized that a deviation occurs in the circumferential direction, it is not possible to quantitatively detect how much deviation occurs in each component of the distribution.

In addition, by performing gas composition analysis in the circumferential direction,
Although it is possible to qualitatively know the deviation of the furnace condition in the circumferential direction, regular sampling of the gas inside the blast furnace is difficult due to the high concentration of dust in the gas and the high partial pressure of water vapor in the gas. This method tends to cause clogging in the pipe system, and has rarely been used in practice as a method for detecting permanent deviations in the circumferential direction.

The present inventors have proposed a new device in order to perform the above-mentioned circumferential gas training analysis substantially simultaneously. (Miseki Akira-22954) Therefore, it has become possible to constantly detect the circumferential deviation by detecting the gas composition in the circumferential direction. In view of the above-mentioned current situation, the present invention aims to provide a method for quantitatively detecting the deviation of the flow in the circumferential direction in a blast furnace, and based on the detection result, the deviation in the flow of the top charge in the circumferential direction. The purpose is to enable specific correction of distribution deviations and achieve further energy savings.

The gist of the present invention is to substantially simultaneously quantitatively analyze the gas components at multiple locations in the circumferential direction of the top of the blast furnace and the entire blast furnace exhaust gas component, and to combine this analysis result with a previously known composite blast composition. A method for detecting circumferential distribution deviation in a blast furnace characterized by quantitatively detecting the distribution of material in the circumferential direction in the blast furnace and the deviation in the flow of the material from the analysis value of the material stored in the furnace top bag. The present invention will be described in detail below.

Broadly speaking, the main elements to pay attention to in a blast furnace are iron, carbon, and oxygen (hereinafter referred to as Fe, C, and 0, respectively).

The access to and from the blast furnace is as follows.
[1-The entire amount of Fe, 90% or more of C, and about half of 0 are brought into the furnace as top charge, and the remaining amount is brought in by air blowing from the tuyere.

The abundance ratio of Fe and ○, which enter as a charge from the top of the furnace, is known in advance by chemical analysis of the charge. '2' On the other hand, regarding the form in which these elements are discharged from the blast furnace, 100% of Fe is discharged from the taphole as hot metal, and an almost constant amount (approximately 10%) of C is discharged from the taphole along with the melt gun. The rest is discharged from the furnace top as exhaust gas, and 0 means 100% is discharged from the furnace top as exhaust gas.

Further, the concentration of each component in the air is uniform in the circumferential direction or can be adjusted (known).

From the above, if the consumption amounts of C and 0 in the charge per unit time are respectively Wc and Wo, and the production amount of Fe is WFe, then from the material balance the following 01,■,'3} formula is obtained. holds true. Wc=i2Qc, i×i (exhaust gas) -28c,
jYj (ventilation) yWFe...
...[1'Wc=i2 is.

, iXi-i28. ,iYi...(21WFe
=6Wo...'3'Here, Xi, Yj: Flow rate Qc, 1' of each component in exhaust gas and ventilation, respectively; 8c, 1: Concentration of c contained in exhaust gas and ventilation, respectively Qo, i, 8 .

, i: concentration y of 0 contained in exhaust gas and blast, respectively
: Ratio of C to Fe in port pig iron, constant value 6: 0 in iron oxide
It is the ratio of Fe to

[1} to [3i In the formulas, Q and 8 are constants derived stoichiometrically, y is a known constant, and 6 is determined by the analytical value of the charging material.

Therefore, once the components and flow rates of furnace top exhaust gas and blast air are determined,
Wc, Wo, and WFe are determined. Now, when this principle formula is applied to regions divided in the circumferential direction inside the furnace, the following is obtained.

Below, as an example, a case where the circumference is divided into four parts will be shown.

As shown in Figure 1, the blast furnace is divided into four regions in a circumferential manner, and the analytical values of the k component of the gas in each region are calculated from xk(1) to xk.
(4), let the flow rate of each region be X(1) to 1)X(1)10Xk(2)X
(2) 10Xk(3)X(3) 10Xk(4)×(4)=x
x(o)×(o) “””{41 holds true, and the '41 formula becomes an equation including four knowledge numbers x(1) to X■.

Therefore, in each region, as the k component, for example, C○, C02
By analyzing the four components of , ratio, and N2 and substituting the numerical values into the formula '4', X(1) to x(4) can be expressed using X(o).

Also, ×(o) can be calculated using the fact that N2 is neither generated nor absorbed in the blast furnace, so YN2 (N2 flow rate during blasting) = xN2 (0)
X(0) holds, therefore x(0)=YN2/xN2(
0) ...'51, and ×(o) is {5
It is determined by one equation.

Since the amount and composition of the composite air blast are known, [X(
o) can be determined, gas flow rates X(1) to X(4) in each region are determined from the '41 formula, and Wc (Y), Wo (So), WFe (Y) (K =
1, 2, 3, 4) can be obtained.

By comparing these values obtained for each region, it is possible to quantitatively determine the ratio of the flow rates of C, 0, and Fe in each region as a circumferential deviation.

As explained in detail above, gas components k (k is C0, C02, H history, N2,...
) and the total blast furnace exhaust gas component k (k is C0, C02,
2, N2,...) at the same time,
This analysis result xk (evening) (k is C○, CQ, ratio, N2,
..., 1, 2, 3, ...) in the evening, and composite blast composition 3
cc, i, 8 and air blowing amount Y, YN2, the ratio 8 of Fe to 0 in iron oxide derived from the analysis value of the top charge, and the ratio y of C to Fe in molten iron. Each flow rate Wc of C, 0, and Fe in each region in the circumferential direction (
(evening), Wo (evening), WFe (so) (evening is 1, 2, 3,・
), and the abundance distribution of the material in the circumferential direction within the blast furnace and the deviation of the material flow can be quantitatively detected.

Furthermore, the ratio R of the charged ore and coke in each region is R
(Evening) = Two regimens…-. - Since '6' can be quantitatively determined, the circumferential distribution deviation in the blast furnace can be specifically corrected using this detection method.

The gas sampling point at the top of the blast furnace may be any suitable space within the blast furnace above the surface of the charge, and is preferably provided, for example, in an uptake which is usually provided in a plurality of rows. Also,
The entire blast furnace exhaust gas is preferably collected after the gases in each region have been sufficiently mixed, and the appropriate location is the outlet of the dust collector that collects gas from the secondary furnace.

In addition, in the above explanation, the exhaust gas flow rate x (so) of each area in the circumferential direction is expressed as {4 by using the gas analysis result xk (so)
', {5} formula, but if the flow rate in each region is directly measured using an appropriate detector, the measured value can be used to calculate [1
', ■, '3} From the formula, Wc (evening), Wo (evening), WFe
(evening) can be found. However, blast furnace exhaust gas contains a large amount of dust, and there are problems such as wear of flow rate detectors and dust accumulation, and it is extremely difficult and impractical to continuously and accurately measure the flow rate of blast furnace exhaust gas in each divided area. do not have. The present invention makes it possible to quantitatively detect the distribution deviation in the circumferential direction inside the blast furnace, which was previously impossible to quantitatively detect. Since it is possible to control the flow distribution in the circumferential direction, even more advanced blast furnace control is possible, which greatly contributes to stabilizing blast furnace operations and saving energy.

Next, embodiments of the present invention will be described.

Gas was introduced into the gas analyzer from each of the four uptakes of the blast furnace through a gas sampling piping system, and each gas was analyzed in a short time (within one rat sand).

In addition, in order to obtain analytical values for all gases, gas was introduced through the gas sampling piping system after the venturi, and gas analysis was performed periodically. The extraction position for gas analysis is shown in Figure 2, and the gas analysis piping system is shown in Figure 3. Figure 4 shows an example of measured values from gas analysis. From these data, the ratio R of hishiri ore to coke in each region was quantitatively determined over a long period of time.
The calculation method for R (evening) is as shown in equation {6). As a result, the value of R(so) has a deviation as shown in Figure 5, and #
1, #2 Compared to R(1) and R(2) on the uptake side,
It was found that R(3) and R(4) on the #3 and #4 uptake sides always showed high values, and it was determined that segregation in the bunker hopper at the top of the furnace was the cause. Therefore, the hottuber was modified, and as a result, the segregation was improved so that almost no segregation was observed, as shown in FIG. 6, and the improvement result could also be confirmed by the deviation detection method of the present invention.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram for calculating deviation in the circumferential direction inside the blast furnace, Figure 2
The figure is an explanatory diagram of the extraction position of the gas analysis piping, Figure 3 is a schematic diagram of the gas sampling system, Figure 4 is a graph showing an example of furnace top exhaust gas analysis values, and Figures 5 and 6 are respectively at the furnace top. 7 is a graph showing circumferential direction deviations in each uptake area before and after distribution improvement. 1...Blast furnace, 2-Gas analyzer, 3...Uptake, 4...Furnace top exhaust gas piping, 5...Dust catcher, 6...Ventil scrubber, 7...Sample gas piping, 8. ...Dust removal filter, 9...Flow rate controller, 10
...Exhaust pipe, #0, × (o), xk (o) ...Respectively, the area of the entire furnace top gas, the flow rate, the analysis value of the k component, #1
~ #4, x (1) ~ ...Ratio between ore and coke. Figure 1 Figure 2 Figure 3 Figure 5 Figure 6

Claims (1)

[Claims] 1 Gas components at multiple locations in the circumferential direction at the top of the blast furnace ■ (K is C
O, CO_2, H_2, N_2,...) and the component ■ of the entire blast furnace exhaust gas are substantially simultaneously quantitatively analyzed, and the analysis result X_K(l) (l corresponds to the measurement point 123...) Based on the concentration of oxygen, carbon, and nitrogen contained in the blast furnace and the amount of air blown, the ratio of Fe to O in iron oxide derived from the analytical values of the top charge, and the ratio of C to Fe in molten iron, It is characterized by quantitatively detecting the abundance distribution of the material in the circumferential direction of the blast furnace and the deviation of the material flow by obtaining the respective flow rates of C, O, and Fe in each region in the circumferential direction. A method for detecting circumferential distribution deviation in a blast furnace.