KR950012396B1 - Control method of blast f'ce gas distribution - Google Patents

Abstract

The predicting method for gas distribution improves the usage of gases and the lifetime of a blast furnace by using the accurate information of gas distribution. The predicting method comprises(A) calculating several parameters of sinter, cokes and gas from the empirical equations; (B) obtaining mass velocity of gas from the pressure gradient equation substituting the calculated parameters; (C) calculating gas mole percentage.

Description

Estimation method of blast furnace gas flow distribution

1 is a reference diagram showing an isosphere divided part in the blast furnace direction.

2 is a triangular graph showing the distribution ratio of the central, intermediate and peripheral flows of the blast furnace estimated according to the present invention.

3 is a blast furnace gas flow distribution estimation result estimated according to the present invention.

The present invention relates to a method for estimating the distribution of gas flow in the blast furnace in the blast furnace process, and more particularly, to a method for estimating the distribution of gas flow in the blast furnace by obtaining the pressure loss distribution in the blast furnace direction between the mass and the blast furnace. It is about.

In the blast furnace operation, it is important to keep the charges in the furnace and the reducing gas produced at the bottom of the furnace in good contact so that the reduction and dissolution of iron ore is properly performed.

If the fluctuation of gas in the furnace occurs, the reduction of iron ore will be uneven, and the melting level of the ore at the bottom of the furnace will be unbalanced, causing abnormalities in charge dropping, such as slip & drop.

Therefore, it is necessary to first understand the gas flow distribution in the furnace. Conventional methods for estimating the distribution of gas flows are difficult to measure the gas flow rate directly because the temperature in the furnace is high and there is a lot of dust in the gas. Therefore, many methods are used to estimate the gas flow indirectly by using the temperature or gas component distribution of the gas in the furnace. Doing. In addition, indirect estimation of the distribution of gas flow in the furnace from the relationship between the inclination ratio of the charged surface and the gas flow velocity during the blowing and in the absence of air flow (Japanese Patent Publication No. 60-39725) and the correction by the mathematical model using the fluid equation Method [M. Kuwabara, I. Much, Tetsu-to-hagane, Vol. 62, No. 5, P3 (1976). In the former case, the inclination angle of the charged material is greatly influenced by the change of the charging method (charging mode), so that the accurate gas flow distribution cannot be estimated when the charging method is changed, and the latter requires a lot of data for calculation. Since the actual blast furnace situation is calculated by a flow equation that is not sufficiently considered, there is also a problem that cannot be accurately estimated.

Accordingly, an object of the present invention is to provide a method for more accurately estimating the gas flow distribution in a blast furnace by obtaining the pressure loss distribution in the furnace direction and estimating the gas flow distribution in the furnace using the same. .

Hereinafter, the present invention will be described in detail.

The present invention relates to a method for estimating the distribution of gas flow in a blast furnace, the method comprising: dividing an area into three parts in the direction of the furnace from the masses to the center, the middle part, and the periphery; Estimating the average particle diameter, particle size segregation index, porosity, shape factor, gas viscosity and gas density of the sintered ore and coke; Substituting the value measured as above into a pressure loss equation to obtain a gas mass flow rate in each of the partitioned sections as described above; The gas flow rate estimation method in the blast furnace comprising the step of estimating the gas flow distribution in the furnace by converting the gas mass flow rate into the standard flow volume flow rate and then obtaining the gas flow fraction in the furnace direction.

Hereinafter, the present invention will be described in more detail.

According to the present invention, in order to estimate the gas flow distribution in the blast furnace, the gas flow distribution in the furnace should be divided into three sections in the direction of the furnace from the bulkhead to the center, middle, and periphery. It is assumed that the gas flow rate and the charge distribution in the chamber are symmetric about the central axis of the furnace.

Next, the average particle diameter, particle size segregation index, porosity, shape factor, gas viscosity and gas density of the sintered ore and coke are estimated by the following formulas (1) to (10).

In the above formulas (1) to (10),

D _PS : Average dineter of sinter (mm)

I _SPS : Particle segregation index of sinter

ε _S : Voidage of sinter

Φ _S : Shape factor of sinter

D _PC : Average diameter of coke

I _SPC : Particle segregation index of coke

ε _C : Voidage of coke

Φ _C : Shape factor of coke

ρ _g : Density of gas (Kg / m ³ )

x: Length of radial direction

θ: Tilting degree of rotating chute (radian)

: Pressure of gas (Kgf / m ² )

: Average molar mass of gas (Kg / Kg-mode)

R: Gas constant (atm Nm ³ / K Kg-mole)

: Temperature of gas (K)

μ: viscosity in gas furnace

Subsequently, the estimated values as described above are substituted into the input loss equation represented by the following equation (11) to find the mass flow rates in the gas flows, that is, the central flow, the intermediate flow, and the periphery of each compartment.

In the formula (11),

△ P / L: Pressure drop (Kg / m ² m)

ε ₁ : void fraction

μ ₁ : Viscosity (Kg / m / sec)

G ₁ : Mass velocity of gas (Kg / m ² / sec)

g _C : Gravitational conversion factor

Φ ₁ : Auerage shape factor of all solid particles

d _PI : Aureage diameter of solid particle (m)

ρ _g : Density of gas (Kg / m ³ )

i: exponent representing the center, middle and periphery

In the formula (11), ε ₁ , μ ₁ , Φ ₁ , d _P1 are obtained as follows.

Where W _c : loading of coke

W _s : Loading amount of sintered ore

Next, after converting the gas mass flow rate (G ₁ ) in each compartment obtained by the above formula (11) into a volume flow rate (V ₁ ) in a standard state as in the following formulas (12) to (14), The flow rate distribution in the furnace is estimated by calculating the gas flow rate fraction X ₁ in the furnace direction.

Where V ₁ : Volumetric flow rate at zone i standard condition (Nm ³ / min)

G ₁ : i-zone mass flow rate (Kg / sec / m ² )

A ₁ : Area i cross section (m ² )

P ₁ : Zone i average pressure (atm)

T ₁ : Zone i average temperature (℃)

VT: total volume flow rate in standard condition (Nm ³ / min)

ε ₁ : i-zone porosity

ρ _gi : mean gas density in zone i (Kg / Nm ³ )

By carrying out the above procedure it is possible to accurately estimate the blast furnace gas flow distribution according to the present invention.

According to the present invention, the gas flow distribution estimation calculation is periodically performed by a computer whenever the temperature, pressure, and gas composition of the blast furnace mass are measured by a shaft sonde. The result can be displayed on the screen. The three coordinate sides of the triangular graph are the central flow, the middle flow, and the peripheral flow, respectively, and are expressed in percent.

The result screen may be displayed as two screens showing the estimation results of the short term (3 days) and the long term (10 days).

On the other hand, the position of the coordinates of the most recent estimation result is indicated by (1), and the previous one is indicated by (2), etc. in order to easily identify the change in time-series fluctuations in the gas distribution.

Hereinafter, the present invention will be described in more detail with reference to Examples.

EXAMPLE

The estimation result estimated according to the present invention is shown in FIG. 3 in comparison with the measurements by blast furnace cross sonde and shaft sonde.

As shown in FIG. 3, in the blast furnace mass zone, when comparing the direction of the furnace, the gas flow rate is higher than the one with the higher furnace temperature, and the gas utilization rate is higher because the porosity is higher because the ore / coke ratio is lower. can do. Therefore, it can be seen that the gas flow estimation results in the furnace agree well with the measurement results of shaft and cross sonde.

As described above, the present invention accurately estimates the distribution of gas flow in the blast furnace, thereby improving utilization of the reducing gas in the furnace compared to the conventional method of estimating the gas distribution only by measuring the temperature by the shaft sonde, and applying excessive heat load to the blast furnace furnace wall. By preventing the long life of the furnace body, it is possible to reduce the production cost of the blast furnace and prevent deterioration of the blast furnace due to instability in the gas flow distribution.

Claims (1)

A method for estimating the distribution of gas flow in a blast furnace, the method comprising: dividing an equal area into three parts in a furnace direction in a block zone, and isolating the central area, the middle part, and the peripheral part; According to the following formulas (1) to (10), the average particle diameters (D _PS and D _PC ), particle size segregation index (I _SPS and I _SPC ), porosity (ε _S and ε _C ), and shape coefficient (Φ _S) And estimating Φ _C ), in-vehicle viscosity (μ) and gas density (ρ _g ); Where x is the street length θ: Slope of the charging swiveling suit p: pressure of gas M: average molecular weight of gas R: Gas constant T: gas temperature) Substituting the estimated value above into the pressure loss equation (ΔP / L) of the following formula (11) to obtain the gas mass flow rate G _S in each of the sections (i) partitioned as above; W _c : Charge of coke W _s : Loading amount of sintered ore After converting the gas mass flow rate G ₁ in each partition section i obtained as described above into the volumetric flow rate V _{1 in the} standard state, as shown in the following equations (12) to (14), the gas in the street-direction direction Obtaining a flow rate fraction X ₁ ; And estimating the gas flow distribution in the blast furnace according to the obtained gas flow rate (X ₁ ).