JPS60243204A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To stabilize conditions in a blast furnace by calcuating the flow rate of gas from the difference in pressure between plural pressure measuring holes arranged in the furnace in the falling direction of starting materials and by controlling the distribution of the flow rate of gas on the basis of the calculated value. CONSTITUTION:Plural pressure measuring holes 1a, 2a are arranged in a blast furnace in the falling direction of starting materials at a prescribed distance (DELTAl) from each other. The difference in pressure between the holes 1a, 2a is measured with a differential pressure gauge 4, and the flow rate of gas is calculated from the measured value. On the basis of the calculated value, the distribution of the flow rate of gas in the furnace is controlled in a movable armor by increasing the amount of ore at the center of the furnace or reducing the speed at the tip of a tuyere.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a blast furnace operating method that measures the gas flow velocity in a blast furnace raw material and makes the gas flow distribution appropriate based on the measured value.

[Conventional technology]

In blast furnace operation, the gas flow velocity distribution in the radial direction and the circumferential direction is an important factor for making the hot metal components uniform, lowering the fuel ratio, and stabilizing the furnace condition. For this reason, the gas flow velocity inside the blast furnace has been measured using various instruments. Conventional measuring instruments include, for example, hot-wire anemometers, tar-5 meters, and fluid anemometers. However, all of these devices have problems such as durability and dust adhesion, and are limited to measurements on the surface of the raw material at the top of the furnace, and cannot directly and continuously measure the gas flow i within the raw material.

[Technical Problems to be Solved by the Invention] The present invention has been made in view of the above circumstances, and its purpose is to directly and continuously measure the gas flow velocity within the raw material and to perform this measurement i1: The purpose is to provide a blast furnace operating method in which the gas flow distribution can always be properly controlled.

[Means for solving technical problems]

That is, the present invention provides at least two pressure detection holes spaced a predetermined distance apart in the descending direction of the raw material in the blast furnace, measures the differential pressure at each pressure detection hole position, determines the gas flow velocity from these measured values, and calculates the gas flow rate. This is a blast furnace operating method that controls the gas flow velocity distribution in the furnace based on gas flow velocity values.

〔Example〕

The present invention will be described in detail below with reference to illustrative embodiments. - First, in the present invention, two blowers Z and 2 are installed in a blast furnace as shown in FIG. These probes 1.2 are
The lower end is provided with pressure detection holes 1m and 2a, and these pressure detection holes 1s and 2- are spaced apart by a predetermined distance (Δj) in the downward direction of the raw material (usually 100 to 200M). Although not shown, these pair of probes 1 and 2 are installed at a plurality of locations in the circumferential direction and diametrical direction of the furnace. Also, the pressure detection hole is 1m.

A probe 3 for detecting gas temperature, gas composition, and pressure is installed at approximately the same position as 2a. Above probe 1.2
is connected to a differential pressure oscillator 4 that detects changes in differential pressure, and the differential pressure oscillator 4 is connected to a data sensor 5. probe 3
is also connected to the data processing device 5.

In the pressure detection holes 1a and 2a, the differential pressure changes as the raw material falls, and this differential pressure ΔP is detected by the differential pressure oscillator 4.Figure 2 shows the differential pressure detected in an actual furnace. Figure 2 shows that there is a clear difference in the differential pressure level between the ore layer and the coke layer.Also, there are slight changes in the differential pressure within each layer, and there are differences in the amplitude. (Figure 3 shows the difference enlarged).

This difference in amplitude is considered to be due to a difference in particle size of the raw material when the raw material passes in front of the pressure detection hole as it descends, and is proportional to the particle size.

In this invention, the gas flow rate is calculated from the measured value of the differential pressure based on the Elgin pressure loss equation shown below.

That is, Ergin's pressure drop equation (1) is generally used to express the air permeability inside a blast furnace.

However, △P: Differential pressure Δ! : Pressure detection end distance? C: Gravitational acceleration (constant) φ: Shape factor (constant) μ: Gas viscosity ρ: Gas density 6: Average particle size U: Gas flow rate ε 2 Porosity From equation (1)... (2) However, μ and ρ are calculated based on gas composition, temperature, and pressure.

(Calculation of average particle size n) Since the amplitude of minute changes in differential pressure in each layer is proportional to the particle size, Xi: amplitude of minute changes in differential pressure ki constant (calculation of porosity ε) It is known from model experiments that it forms a normal distribution and that the porosity in an actual reactor is proportional to the spread of the distribution. Therefore, the porosity ε can be calculated from the following equation.

However, is a constant.

In this way, the gas flow velocity is determined based on the differential pressure change of each pressure detection hole, the gas flow velocity distribution in the radial direction of the furnace and the gas flow velocity distribution in the circumferential direction of the furnace are determined, and the gas flow velocity distribution is determined based on these measured values. control so that it is appropriate.

For example, if the gas flow rate in the center of the furnace is high, the gas flow rate can be adjusted to an appropriate level by using a louver pull armor to increase the amount of ore in the center of the furnace, by reducing the tuyere tip speed, or by using a combination of these operations. shall be taken as a thing.

If the gas flow rate around the furnace is high, the gas flow rate can be adjusted to an appropriate level by increasing the amount of ore around the furnace using a looper armor, by increasing the tuyere tip speed, or by using a combination of these operations. make it a thing.

Furthermore, if the gas flow velocity in the circumferential direction of the furnace is non-uniform, the flow rate of each panel is controlled to make the gas flow velocity uniform in the circumferential direction.

By controlling the gas flow velocity distribution in this manner, it is possible to effectively utilize the gas, form appropriate reduction, softening, and melting zones, and reduce slip. As a result, variations in the hot metal components are reduced, the fuel ratio is lowered, and the furnace conditions can be stabilized.

For example, before implementing the blast furnace operating method of the present invention, the Si content in hot metal was 0.50% per day on average and 0.70% per day at maximum.
, the minimum is 0.30%, the difference is 0.40%, and there are 4 flts. By performing the method of this invention, the average is 0.45%, the maximum is 0.55%, the minimum is 0.35%, and the difference is 0.20. %.

This result shows that the dispersion of hot metal components has been significantly reduced.

In addition, in the conventional method, slips occurred 10 times per day, but by implementing the present invention, the number of slips decreased to 1 to 2 times per day, which shows that the number of slips has significantly decreased.

Furthermore, in the conventional method, the fuel ratio was 490KP/Tpig, but by implementing this invention, it has been reduced to 470KP/Tpig.
It becomes Tp1g, and it can be seen that the fuel ratio is decreasing.

〔Effect of the invention〕

As is clear from the above results, according to the present invention, the gas flow velocity in the blast furnace raw material can be measured continuously, so that the gas flow velocity distribution in the furnace can always be appropriate, and the molten metal It is possible to equalize the components, lower the fuel ratio, and stabilize the furnace condition.

[Brief explanation of the drawing]

Figs. 1 to 3 show an example of the method of the present invention, Fig. 1 is an explanatory diagram showing the installation state of the probe, Fig. 2 is an explanatory diagram showing the change in differential pressure over time, and Fig. 3 is an explanatory diagram showing the installation state of the probe. FIG. 2 is an explanatory diagram showing minute changes in differential pressure over time, with part A in the diagram enlarged. 1.2...probe, 3...probe, 1 a, 2
a...Pressure detection hole, 4...Differential pressure oscillator, 5...
Data processing equipment. Applicant's agent Patent attorney Takehiko Suzue Figure 2 Seikaku

Claims (1)

[Claims] (11) In the blast furnace, at least two pressure detection holes are provided at a predetermined distance apart in the downward direction of the raw material, and the differential pressure at each pressure detection hole position is measured, and the gas A blast furnace operating method characterized in that the gas flow velocity distribution in the furnace is controlled based on the gas flow velocity value. (2) A patent characterized in that the gas flow velocity is calculated based on the Elgin pressure drop formula. The method of operating a blast furnace according to claim 1. (3) The particle size and porosity of the raw material are calculated based on minute changes in the differential pressure in each pressure detection hole, and the gas The blast furnace operating method according to claim 1, characterized in that the flow rate is increased.