JP2005281756A - Method for controlling tapped molten pig iron and slag in blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controlling tapped molten pig iron and slag in a blast furnace by which for securing good molten pig iron quantity, the adjustment of a space shape before a molten pig iron tapping hole is easily performed. <P>SOLUTION: Before or at the same time of discharging the molten pig iron and slag, the spout of pulverized fine coal from a tuyere 2 at the upper part of the molten pig iron tapping hole 7 is reduced or made to be zero and then, the consumption of the coke in the raceway 3 at the lower part of the tuyere, that is, at the upper part of the molten pig iron tapping hole, is promoted and therefore, the space 6 before the molten pig iron tapping hole 7 is enlarged by floating up the coke filled layer 4 before the molten pig iron tapping hole 7 to increase the molten pig iron and slag quantity. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a blast furnace discharge control method when discharging the hot metal in the blast furnace together with the hot metal from the discharge hole.

  Generally, in a blast furnace, coke, ore, etc. are introduced from above, and hot air is blown from a tuyere provided at the lower part of the kiln, so that a temperature rise similar to combustion occurs in a so-called raceway in front of the tuyere. This causes the ore to melt and flow down to the hearth as hot metal and hot metal. Thus, the hot metal and hot metal (hereinafter also simply referred to as hot metal) stored in the hearth part of the blast furnace are discharged as the hot metal from the tap hole formed at the lower end of the furnace wall.

As a conventional control method at the time of the discharge, for example, based on the state of the output from the output hole, specifically, the ratio of the output and the output, the output from the output hole to the blast furnace. By adjusting the ratio of the pushing amount of the mud to be pushed in and the depth of the tap hole, that is, the depth index, there is a type that controls the space before the tap hole, that is, the so-called free space, to ensure a good tapping. (For example, patent document 1).
JP 2002-60819 A

However, in the conventional tapping control method, first, the state of tapping discharged from the tapping hole is detected, and then the depth index consisting of the ratio between the mud pressing amount and the tapping depth is adjusted, After that, since the form of the space before the tap hole is adjusted to secure the amount of the tap, there is a problem that it takes time and effort to adjust the form of the space before the tap hole.
An object of the present invention is to provide a method for controlling the output of a blast furnace in which the form of the space before the tap hole is easily adjusted in order to ensure a good amount of tap.

  In order to solve the above problems, the blast furnace discharge control method of the present invention is a blast furnace discharge control method for discharging the molten iron in the blast furnace together with the molten iron from the discharge hole. The pulverized fuel introduced from the tuyere above the tap hole is less than the pulverized fuel introduced from the other tuyere or zero.

  Thus, according to the blast furnace tapping control method of the present invention, the pulverized fuel introduced from the tuyere above the tapping hole is less than the pulverized fuel fed from the other tuyere, or By setting it to zero, the consumption of coke before the tap hole is increased, and as a result, the space before the tap hole is increased and the amount of the tap is increased.

Next, an embodiment of a method for controlling the output of a blast furnace according to the present invention will be described in detail with reference to the drawings.
First, in FIG. 1, the longitudinal cross-sectional view from the tuyere of the blast furnace of this embodiment to a hearth part is shown. A large number of tuyere 2 as hot air blowing ports are provided in the lower part of the furnace wall 1 of the blast furnace over the entire circumference. The tuyere 2 is supplied with gas heated to about 1000 ° C. in a hot air furnace (not shown), and the hot air blown out from the tuyere 2 into the blast furnace is called a raceway 3 in a coke packed bed 4 to be described later. A high heat space is formed. The tuyere 2 is provided with a nozzle 10 for ejecting pulverized fuel, specifically, pulverized coal. Normally, operation is performed while ejecting pulverized coal from the nozzles 10 of all tuyere 2. Do.

On the other hand, coke, ore, and the like charged from above the blast furnace form a coke packed bed 4 made of only coke below the tuyere 2. This is because the ore is melted by high-temperature heating in the raceway 3 and flows down to the hearth as hot metal and hot metal, that is, hot metal 9.
Further, the hearth part is covered with a mud made of a refractory material to constitute a mud deposition layer 5. This mud is used to close the tap hole 7 drilled from the furnace wall to the mud deposition layer 5, and this mud deposition layer 5 protects the original hearth.

When a certain amount of hot metal 9 accumulates on the hearth of the blast furnace, that is, on the mud deposition layer 5, it penetrates through the tap hole 7 from the furnace wall 1 to the mud deposition layer 5, and from the tap hole 7. The hot metal 9 is discharged as an output.
In the present embodiment, the amount of pulverized coal ejected from the tuyere 2 above the spout hole 7 prior to or simultaneously with the discharge of the slag is changed to the amount of pulverized coal ejected from the other tuyere 2. The amount of pulverized coal discharged from the tuyere 2 above the tap hole 7 is reduced to zero. The reason will be described below.

  FIG. 2 is a simplified representation of the inside of the blast furnace of FIG. 1, and it is assumed that the inside of the blast furnace is filled with coke and ore. As described above, the tuyere 2 is provided over the entire circumference of the furnace wall of the blast furnace 1, so that the coke packed bed 4 in the furnace is surrounded by the outer periphery of the furnace, that is, the region A divided by a broken line in the drawing, Consider the central portion, that is, the region B divided by a broken line in the figure. Among these, the coke in the coke packed bed 4 existing in the outer peripheral portion (region A) of the furnace approaches directly from above toward the raceway 3 (enters the raceway 3). On the other hand, the coke in the coke packed bed 4 existing in the center of the furnace (region B) once falls from the tuyere level as it comes out, and floats and sinks as the hot metal level rises and falls. Approaching Way 3 from below (entering Race Way 3). The larger the coke flying height in this region B, the larger the space 6 before the tapping hole at the time of tapping, and the amount of tapping increases. For this purpose, it is desired that the coke consumption in the raceway 3 above the tap hole is large.

  On the other hand, the pulverized coal ejected from the tuyere 2 described above is used to keep the raceway 3 at a high temperature, but if the amount of pulverized coal ejected becomes too large, unburned char (incombustible material in the coal). ) And ashed product, a hardened layer called a shell formed outside the raceway 3 is enlarged. Since this shell has neither good air permeability nor liquid permeability, it inhibits the consumption of coke and also inhibits the floating of the coke packed layer 4. Further, since oxygen is consumed in the combustion of the pulverized coal itself ejected above the tap hole 7, the consumption of coke below it is inhibited, and this also inhibits the floating of the coke multi-layer 4. The

Therefore, in this embodiment, the amount of pulverized coal ejected from the tuyere 2 above the tap hole 7 is made smaller than the amount of pulverized coal ejected from the other tuyere 2 or above the tap hole 7. The consumption of coke in the coke packed bed 4 above the tap hole 7 is promoted by making the amount of pulverized coal ejected from the tuyere 2 zero, so that the coke packed bed 4 near the tap hole 7 is It floats up, the space 6 before the tap hole 7 is enlarged, and the amount of tapping increases.
Thus, according to the blast furnace tapping control method of the present embodiment, the amount of pulverized coal ejected from the tuyere 2 above the tapping hole 7 is changed to the amount of pulverized coal ejected from the other tuyere 2. By reducing the amount of pulverized coal ejected from the tuyere 2 above the tap hole 7 to be smaller, the space 6 in front of the tap hole 7 is enlarged and the amount of tapping is increased. Therefore, it is possible to easily secure the amount of output without taking time and effort.

It is a longitudinal cross-sectional view which shows the state from the tuyere of a blast furnace to a hearth part. It is explanatory drawing of an effect | action of the output control method of this invention in the blast furnace of FIG.

Explanation of symbols

1 is a furnace wall 2 is a tuyere 3 is a raceway 4 is a coke packed bed 5 is a mud deposit layer 6 is a space 7 is a spout hole 8 is a flow control valve 9 is a hot metal 10 is a nozzle

Claims (1)

  A method for controlling the blast furnace discharge when discharging the molten iron in the blast furnace together with the molten iron as an output from the tap hole. A method for controlling the output of a blast furnace, characterized in that the amount of fuel is less than or less than the amount of pulverized fuel introduced from the tuyere.

Images