JPS6039725B2 - Blast furnace gas flow rate measurement method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring gas flow distribution on the surface of a charge in a blast furnace.

Generally, when operating a blast furnace, the ore charged into the furnace,
Solid materials such as coke (hereinafter referred to as the charge) and reducing furnace gas (hereinafter simply referred to as the furnace gas) generated when the coke in the charge is burned by hot air blown to the lower part of the furnace. ), and it is important to maintain the reduction and dissolution of the ore in an appropriate state, and for this purpose, it is necessary to reliably understand the gas flow distribution in the furnace.

That is, if the flow of gas in the furnace is partially uneven and the gas flow distribution is significantly disturbed, there will be parts where there is a lot of gas flow and parts where there is less gas flow, and the reduction ratio of the ore will become non-uniform. As a result,
The ore melting level in the lower part of the furnace is unbalanced and the shelf hangs.
This will cause abnormalities in the descent of the burden such as slips, which will greatly disrupt the stability of blast furnace operations. If such a phenomenon of uneven gas flow in the furnace occurs, it is necessary to charge more ore to the areas where there is a large amount of gas flow. Measures are being taken to improve the disordered distribution. Therefore, it is extremely important to accurately detect the gas flow distribution in the furnace in order to maintain stable operation of the blast furnace. However, in the past, it was difficult to directly measure the gas flow rate because the gas temperature on the surface of the charge in the furnace □ section varied over a wide range from 50 to 8003 C, and because a large amount of dust was mixed in the gas in the furnace. Therefore, the only method available is to measure the temperature and component distribution of the gas in the furnace and indirectly estimate the change in the gas flow distribution in the furnace from these changes.

However, with this method, changes in the temperature and composition of the gas in the furnace are not necessarily caused only by changes in the gas flow rate, but also due to changes in the amount of the charge, the proportion of coke ore, the properties of the charge, etc. Change. Therefore, there is a problem in that the accuracy of estimating the gas flow velocity distribution in the furnace is poor and the charge distribution cannot be accurately controlled. In order to solve these problems, the present invention provides a method for accurately grasping the gas flow velocity distribution in the furnace.

The principle of measuring the gas flow velocity distribution in the furnace in the present invention is that when the blast furnace charge is charged into the furnace, the shape of the pile formed in the furnace changes in accordance with the gas flow distribution in the furnace at the time of charging. , the shape of the charge piled up immediately after charging is measured, and the gas flow distribution is determined based on the results.

That is, when the charges such as coke and ore used in a blast furnace are charged into the blast furnace, they are deposited at a certain angle as shown in FIG.

Generally, the angle formed between the charge surface and the horizontal plane at this time is called the inclination angle 8, but this inclination angle varies greatly depending on the particle size, density, porosity of the charge and the gas flow rate during charging.
In this case, it is known that the inclination angle is generally expressed by the following formula. Cape/tana.

=1-[Masuko Ju I. 75] [Short key] X (vessel) (support)
．．・Here: 8 Inclination angle (o) under gas flow: 8o:
Internal friction angle (o) Go: Charge porosity (-) Rep: Particle Reynolds number (1) Dp particle diameter (m), pf: Gas density (k9/), u: Gas flow rate (m/s), p: Particle density (kg/) Medium: Shape factor, g: Gravitational acceleration (m/sec2) The river formula is 8:8o at U = 0 (no wind), U = Umf (Umf is the starting speed of particle fluidization m/s) becomes 8=00.

Therefore, the m formula can be rearranged as follows. 8/8.

=f[1-(U/Umf)]...■f: Symbol representing a function Umf: Fluidization start speed Therefore, separately outside the furnace, calculate the physical property values unique to the charge, Dp, pb, 8o. , measuring the inclination angle 8 under gas flow for these charges, a/8.

Figure 1 is obtained by determining the relationship between and Umf. Here, the fluidization start speed Umf is generally determined by the particle size range of the charge charged into the blast furnace (coke: 10 to 70 Yanagi, ore 5
~50 side) is known to be calculated using the following formula. Umf = 0.12 no 3 evenings (pb-pf) Dp/pf
...(3} Therefore, particle diameter (Dp), particle density (pb
) and the density of the gas (pf), it is legal to use Um
f can be calculated.

Here, the particle diameter (Dp) is generally measured in the case where the charging method, charging amount, charging ratio, etc. change as a particle size distribution change in the diameter direction of the blast furnace in an outside-furnace test, and at the same time, the particle density (pb) is also measured. Since both are measured, it is easy to understand both. Furthermore, the gas density (pf) can be easily calculated using the Boyle-Scharr law since the furnace top pressure (PT), furnace top temperature (T), and gas components are measured. In this case, the changes in gas components are gas temperature (T), furnace top pressure (P
The effect on the gas density (pf) is smaller than when T) is changed, so even if the gas density is calculated by regarding it as a constant component in the diametrical direction, no large error will occur. On the other hand, in a blast furnace,
Techniques have been developed that can measure the shape of the deposits charged in the furnace with a high degree of accuracy (for example, the Japanese Patent Publication No. 56-9644 as a profile meter using scissors and microwaves).
, Utility Model Publication No. 54-60608).

Therefore, the inclination angle of the charge can be easily determined from the shape of the charge piled up in the furnace. Furthermore, 8/8o in formula (2) can be easily calculated. In other words, when measuring the shape of the burden pile, the height h and the horizontal distance can. Leg 8 = Yozo Kisan A4} h: Height from a certain reference plane (m) ×: Horizontal distance from a certain reference point (m) i: Suffix indicating the measurement position Therefore, the slope obtained by the formula {4} From the angle 8 and the inclination angle oo in no wind, which was determined in advance by an outside furnace test, a/ in the formula ■
8.

is found. Therefore, we discussed the value of U/Umf corresponding to this 0/ao using Fig.
By substituting f, the gas flow velocity at the position showing the inclination angle 8 of the bag pile shape can be easily determined. As explained above, in the present invention, the calculation procedure is shown in FIG. PT) and gas density (pf)
The fluidization start speed (Umf) of the charge is calculated from this gas density (pf) and the charge particle size (Dp) and density (pb) determined by the outside-furnace test.

On the other hand, we separately measured the shape of the charge accumulation in the □ section of the furnace, calculated the inclination angle 8 for each measurement point from this shape, and obtained the charge inclination angle 8 in no wind conditions by an outside-furnace test. Calculate 8/8o from . U/Umf corresponding to 8/8o obtained in this way
The value of . To explain the present invention based on an embodiment, FIG. 3 shows an example of the equipment configuration of a laser brofilmeter for measuring the deposition shape of the charge 1 in the blast furnace section. An optical device, 4 is a Caesar, 5 is a light receiver, and 6 is an arithmetic unit that calculates and outputs an inclination angle a for each measurement point from the measured deposition shape of the charge.

7 is a mobile gas distribution measurement sonde that measures the gas temperature and component distribution on the surface of the charge; 8 is a mount; 9 is a measuring device that outputs the gas temperature T and components detected by the sonde 7; 10 is a deposition shape , is a converter that outputs the furnace top pressure (PT), charging method, etc. to the calculator 11 based on the operating conditions at the time of gas distribution measurement.

The calculator 11 calculates the gas density (pf) for each measurement point from the oblique angle 8, the gas temperature T, the gas components, and the furnace top pressure (PT), and also calculates the gas density (pf) of the charge determined in advance outside the furnace. Particle size distribution, density and windless inclination angle8. is stored, and the charge particle size (DP) and density (pb) at each measurement point are determined by making this correspond to the charging conditions, and the gas flow rate U is calculated. Reference numeral 12 denotes a display device that displays the calculated gas flow rate in a manner that allows the blast furnace operator to easily determine whether or not the charge distribution control is possible.

Examples of gas flow rate calculations according to the present invention are shown in FIG.

The charging method at this time is C↓C↓○↓○↓ (↓ is a symbol indicating the timing of charging into the furnace, C is coke, 8' ore)
The pressure at the top of the furnace is 1.0 k9/force, the density of ore is 3.2 k9/force, and the angle of inclination is 360. Figure 4 A shows the gas temperature distribution in the diametrical direction at the mouth of the blast furnace as determined by a mobile gas distribution measuring sonde. It is shown in height. Figure 4 C shows the charge angle angle 8 determined for each measurement point interval from the measurement results in Figure 4.
It is. Figure 4-2 shows the particle size distribution of the ore under the Hishiri method on the day determined by the outside-furnace test. The tree in Figure 4 shows the gas flow velocity distribution on the surface of the charge obtained by the method of the present invention from these measurement results.
This figure shows the change in the gas flow velocity distribution at the furnace mouth when changing from C↓C↓○↓00↓. As described above, according to the present invention, it is possible to reliably grasp the gas flow velocity distribution in the □ part of the furnace, which could not be directly measured in the past, and it is possible to change the charging conditions etc. to determine the gas flow distribution in the blast furnace. It is possible to obtain extremely effective detection information for controlling blast furnace operating methods within an appropriate range.

In addition, as an example of the present invention, a deposition shape measuring device is used.
Although gas distribution is measured using a sensor-type profile meter and a moving sonde, the purpose of the present invention is not limited to these devices. It is clear that everything that can measure temperature distribution is included.

However, the number of measurement points in the diametrical direction in this field greatly affects the accuracy when calculating the gas flow velocity distribution. 20 points or more (measurement interval 0.5
(below) is desirable. If the charge deposition shape measurement interval does not match the distribution measurement interval, it is possible to estimate the gas temperature and components by interpolation from the gas distribution value in correspondence with the deposition shape measurement position.

[Brief explanation of drawings]

Figure 1 is 8/8. FIG. 2 is an explanatory diagram showing the calculation procedure of the present invention, FIG. 3 is an equipment configuration diagram in the present invention, and FIG. 4 is an explanatory diagram showing the calculation results. 1 is the contents in the blast furnace, 2 is the laser generator, 3 is the projector, 4 is the laser, 5 is the light receiver, 6 is the computing unit, 7 is the sonde, 8 is the sonde mount, 9 is the gas temperature, components A measuring device that outputs 1
0' is a converter that outputs operating conditions, 11 is a calculator, 12
is an indicator. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 Measure the gas temperature on the surface of the charge inside the blast furnace, calculate the gas density inside the furnace from this temperature value and the pressure at the top of the furnace, and calculate the particle size distribution of the charge previously determined outside the furnace based on this gas density. The fluidization start feed rate U_m_f of the charge is calculated from Find the inclination angle θ of
Find the ratio θ/θ_0 of
A method for measuring gas flow velocity in a blast furnace, characterized in that the in-furnace gas flow velocity U at the position where the inclination angle θ is determined is calculated by determining /U_m_f in advance.