JPS58674Y2 - Internal structure of blast furnace bottom - Google Patents

Description

[Detailed description of the invention] This invention relates to the internal structure of the furnace bottom that extends the life of the blast furnace.

In general, the life of a blast furnace is affected by various factors, but corrosion damage a on the inner wall 2 of the furnace bottom 1 shown in FIG. 1 is particularly problematic.

In other words, in the conventional furnace bottom structure, as shown in FIG. Furnaces have been constructed by laying bricks in a cylindrical shape with vertical walls against a horizontal bottom surface 5 similar to the shape of the inner walls 2 up to the level facing.

However, as a feature of the above-mentioned corrosion damage a, as compared to the profile at the time of construction as shown by the imaginary line C in FIG. 1, the erosion near the inner wall of the furnace in the radial direction of the bottom surface of the furnace is larger than that of the core.

The causes of this include problems with the flow of hot metal and slag around the bottom of the furnace, and structural problems due to the brick material and brickwork in this area.

This idea was made as a result of conducting a model fluid experiment to examine the influence of the shape of the furnace bottom formed by the brickwork on the flow of hot metal slag, and the influence of the flow of hot metal slag on the corrosion damage a of the furnace bottom.

The experimental equipment was designed so that the upward inclination angle α of the taphole 3 was 1 as shown in Figure 3.
5°, an annular inclined bottom surface 6 with a downward slope from the level face of the gun outlet to the circular horizontal bottom surface 5 is provided, and an included angle θ (hereinafter referred to as corner angle) between the horizontal bottom surface 5 and the inclined bottom surface 6 in the radial direction of the hearth bottom. θ) from 90° to 180° - α = 165°
The direction of fluid flow during ironing was investigated with various changes.

The results are shown in Figure 4 for the case of θ = 90°, and Figure 5 for the case of θ = 90°.
150' is illustrated as an example.

In other words, the larger the corner angle θ, the smaller the vortex flow that moves downward along the inclined bottom surface 6 from the taphole level surface shown by the arrow.
In particular, when θ is more markedly reduced than when it is 130°, and when θ is larger than 180°-α=165°, the pig iron storage capacity of the hearth decreases, causing a problem in which the level of hot metal in the furnace increases.

In addition, it was confirmed that there was a problem in that the amount of erosion caused by the eddy flow on the inclined surface of the furnace bottom increased.

It was also recognized that the above-mentioned vortex flowing downward from the level of the taphole has a significant adverse effect on the erosion of the furnace bottom bricks and is the main cause of the occurrence of erosion damage a.

Next, the results of implementing this invention will be shown.

According to the results of the above-mentioned model fluid experiment, the corner angle for a blast furnace with an internal volume of 2150 m3 was set to θ = 1, which falls within the scope of this invention.
The furnace was built and operated with the inner shape of the hearth bottom set at 40° (α-15°) as shown in Figure 6, but the corrosion status of the hearth bricks after use was as shown in Figure 7. As shown in the figure, the corrosion of the furnace walls and slanted bottom surface has been significantly reduced without causing any corrosion damage a, and the operation continues without any problems.

[Brief explanation of drawings]

Figure 1 is a cutaway front view of the main part of the blast furnace bottom showing corrosion damage to the bottom of the furnace, Figure 2 is a cutaway front view of the main part of the bottom of the blast furnace shown in Figure 1 during construction, and Figure 3 is a model fluid experiment. Figure 4 is an explanatory diagram of the flow situation when the corner angle is 90°, Figure 5 is an explanatory diagram when the corner angle is 150°, and Figure 6 is an explanatory diagram when the corner angle is 140°. FIG. 7 is a front view showing the internal shape of the hearth bottom during construction of the present invention, and FIG. 7 is a front view showing the state of consumption of the hearth bottom shown in FIG. 6 during use. In the diagram: 1...Furnace bottom, 2.2'...Inner wall, 3...Outlet 1 piglet, 4...Tap, 5
......Horizontal bottom surface, 6......Slanted bottom surface, a.
...Erosion damage, b...Taphole level surface, C
・・・・・・The bottom profile of the furnace at the time of construction.

Claims (1)

[Claim for Utility Model Registration] The bottom shape of the blast furnace is a mortar shape that extends from the cylindrical inner wall of the sump to the level surface of the taphole, passes through the annular sloped bottom surface with a downward slope to the core, and continues to the circular horizontal bottom surface. The inner structure of the bottom of a blast furnace is formed so that the included angle θ between the inclined bottom face and the horizontal bottom face in the core direction is 130° and θ≦180°−α (α is the taphole inclination angle).