JPH0313515A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To reduce wear of furnace bottom refractory and to stabilize the blast furnace operation by specifying angle of iron tapping hole in the blast furnace to the horizontal plane in the blast furnace operation. CONSTITUTION:The iron tapping hole 1 in the blast furnace penetrated the refractory 2 and is in contact with molten iron 3 and holds so that the angle to the horizontal plane comes to in the range of 0-11 deg.. By this method, distance L1 between the upper interface of molten iron 3 and the furnace bottom, is increased and flowing quantity of the molten iron 3 in the furnace bottom at the time of iron-tapping the reduced. As a result, the damage of the refractory 2 is reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method of operating a blast furnace.

[Prior Art] In the operation of a blast furnace, the maintenance and management of the refractory at the bottom of the furnace that holds hot metal is an issue that not only affects the life of the blast furnace but also has a large impact on the operation.

In other words, when the erosion of the high FF bottom bricks progresses, the heat loss from the furnace bottom increases, and the fuel ratio (
The fuel required to produce a unit amount of hot metal increases, and the [S1] concentration in the hot metal increases.

For this reason, in conventional technology, when the erosion of the bottom bricks progresses, iron sand containing titania (Ti02) is inserted into the blast furnace to cause Ti compounds such as TiN to form on the top of the bricks where the erosion is progressing, thereby causing damage. Erosion of the bricks at the bottom of the furnace was suppressed by repairing the area or spraying water on the bottom of the furnace to cool the area.

Problem I that invention C aims to solve! ] However, the conventional technology has the following problems. That is, (1) By administering titania into the blast furnace, Ti02 in the blast furnace slag increases and the fluidity of the slag decreases, making it difficult to discharge it outside the furnace and causing poor furnace conditions.

■There is a limit to how much water can be sprinkled at the bottom of the furnace, and the cost of powering the watering pump is high.

It is an object of the present invention to solve the above-mentioned problems and to provide a blast furnace operating method that allows bottom bricks to be maintained and managed effectively at low cost and that provides stable operation.

[Means for Solving the Problems] A blast furnace operating method according to the present invention is a blast furnace operating method in which the angle between the tap hole of the blast furnace and the horizontal plane is maintained in the range of 0 to 11 degrees.

[Function] The blast furnace operating method of the present invention maintains the angle between the tap hole of the blast furnace and the horizontal plane in the range of 0 to 11 degrees, thereby reducing the distance between the tap hole opened in the inner wall of the refractory and the bottom of the furnace. increases, the flow rate of hot metal at the bottom of the furnace during tapping decreases, and damage to refractories is reduced.

[Example] FIG. 1 is an explanatory diagram showing an example of the present invention. The tap hole 1 penetrates the refractory 2 and is in contact with the hot metal 3. The angle it makes with the horizontal plane is α. In this embodiment, α is 9 degrees. At this time, the distance from the bottom of the furnace to the upper interface of the hot metal is L
It is l. A thermocouple 5.6 is embedded in the refractory 2, and the state of wear and tear on the refractory is indirectly measured by temperature. Thermocouple 6 is located closer to the hot metal than thermocouple 5. As the number of times of tapping increases, the profile 9 at a part of the bottom corner of the furnace is worn out like the profile 4 due to the flow of hot metal. However, when α is set to 11 degrees, the tapping lower (indicated by the dotted line) is located closer to the bottom of the furnace than in the example of the present invention, and the upper interface of the hot metal (indicated by the dotted line) is located closer to the bottom of the furnace than in the example of the present invention. The distance from the bottom of the hearth is Ll, and Ll <L.

, the wear profile of the refractory in this case is 8
(Indicated by the dotted line) (however, the number of taps is the same as in this example).As shown in the figure, as α increases, the distance between the tap hole opened in the inner wall of the refractory and the furnace bottom increases. As a result, the flow rate of hot metal at the bottom of the furnace during tapping increases, and damage to the refractory increases.

FIG. 2 shows the measurement results using thermocouple 5.6 in FIG. 1. In the figure, the horizontal axis shows time (days) and the vertical axis shows temperature. The ○ mark is the measurement result by thermocouple 6, and the * mark is the measurement result by thermocouple 5. Before 1 hour a, α was 11 degrees. After one hour a, α is 9 degrees. In this way, by decreasing α, the wear of the large refractory at the bottom of the furnace is reduced, and the temperature of the refractory is also lowered.

If α is a more negative angle than O, it is impossible for α to exceed O because hot metal slag will be directly scattered to workers and opening equipment during opening. On the other hand, if α is selected to a value exceeding 11 degrees, the bottom refractory will be severely worn out and the operating cost will increase significantly. In addition, if the furnace condition is poor, by setting α to zero and allowing the upper layer of hot metal in the furnace to flow out quickly:
Measures can be taken to restore the furnace condition. therefore,
By setting α to 0 to 11 degrees, it became possible to stabilize blast furnace operation. In particular, the amount of heat lost from the bottom of the furnace was reduced, making it possible to lower the blast furnace fuel ratio.

[Effects of the Invention] As described above, according to the present invention, by setting the angle between the tap hole and the horizontal plane to 0 to 11 degrees, wear and tear on the furnace bottom refractory is reduced, blast furnace operation is stabilized, This has the effect of reducing operating costs.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of the present invention, and FIG. 2 is a measurement result using a thermocouple. 1... Tapping port, 2... Refractory, 3... Hot metal, 4...
...Profile, 5.6...Thermocouple, 7...Tapping port, 8...Wear profile of refractory, 9...Profile of part of hearth bottom corner.

Claims (1)

[Claims] A method for operating a blast furnace, characterized in that the angle between the tap hole of the blast furnace and a horizontal plane is maintained within a range of 0 to 11 degrees.