JPH0619088B2 - Oxygen blast furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION “Object of the Invention” (Field of Industrial Application) The present invention relates to an iron blast furnace, and more particularly to an oxygen blast furnace in which preheated gas is blown from a shaft.

(Prior Art) Conventionally, in a so-called blast furnace operating method for producing pig iron from ore, although oxygen is slightly enriched, when it comes to a highly productive practical blast furnace, almost all of the high temperature from the tuyere is high. The main purpose is air blowing. In this case, about 79% of the air
N _2, which accounts for are not involved directly in the reduction of iron ore,
It gave a huge amount of sensible heat to the charge from the tuyere to the stock line, and played the role of heat reinforcement necessary to actively carry out gas reduction, so it was not necessary to supply heat from other than the tuyere. In the oxygen blast furnace which is being developed in recent years from the viewpoint of improving the productivity of the blast furnace, in addition to addition of top gas for temperature control against temperature rise at the tuyere, addition of steam, etc. from or near the tuyere, Due to the decrease in the gas amount due to the absence of N _2, the gas reduction region is narrowed to 700 ° C. or more, and the temperature in the upper part of the furnace is lowered, so that heat supply from the shaft portion is required.
For example, Japanese Unexamined Patent Publication No. 60-159104 discloses that a part of the furnace top gas is taken, burned, and blown from a shaft. Also, although it is not an oxygen blast furnace, high oxygen enriched blast and regenerated reducing gas of the furnace top gas are blown from the tuyere.
Also in 2966, the non-oxidizing gas is blown from the shaft portion in order to fill the gas shortage.

However, all of them were blown from a plurality of fixed nozzles provided on the furnace wall, and there was a defect that preheated gas did not easily reach the core.

(Problems to be Solved by the Invention) The present invention has been devised in view of such a current situation, and a part or all of a plurality of conventional fixed nozzles is used as a movable nozzle to supply gas to the core. It is an object of the present invention to provide an oxygen blast furnace in which the temperature of the contents inside the furnace can be freely adjusted, the reduction region is expanded to reduce the fuel ratio, and long-term stable operation is possible by facilitating the arrival.

“Structure of the Invention” (Means for Solving Problems) In order to achieve the above-mentioned object, the present inventors have made a part or all of a plurality of preheating gas blowing nozzles provided in a shaft portion in a core direction. We propose an oxygen blast furnace, which is characterized by its ability to move forward and backward.

By adopting the present invention, it is possible to control not only the heat supply to the upper part of the furnace but also the temperature distribution of the temperature inside the furnace, and it is also possible to blow into the core. And stable operation can be continued for a long period of time.

(Operation) In the present invention, the oxygen blast furnace means an oxygen concentration of 40% from the tuyere
This is a blast furnace in which the above gases are blown at room temperature and preheated gas is blown from the shaft to operate.

FIG. 1 schematically shows a plan view of a shaft portion of a blast furnace in which a fixed nozzle and a movable nozzle used in the present invention are provided.

In this drawing, an example in which a fixed nozzle 2 and a movable nozzle 3 are alternately provided on the furnace wall 1 is shown.
There may be one movable nozzle for every three nozzles, which can be arbitrarily selected depending on the furnace volume or the amount of gas blown from each nozzle. It should be noted that the movable distance of the movable nozzle needs to be designed so that it can be inserted into the furnace up to the position where the tip position reaches from the furnace wall to near the core.

Incidentally, in carrying out the present invention, preheating gas shall be blown while confirming an appropriate effect under the conditions of pre-measurement of gas temperature distribution in the furnace by an intermediate sonde, etc., and measurement of temperature distribution of the contents of the furnace interior. . In order to exert the effect of the present invention, it is necessary to provide at least three movable nozzles at equal intervals.
Also, it is needless to say that the amount of gas blown into each type of nozzle must be variable.

(Example) FIG. 3 is a schematic view in which the movable nozzle 3 is installed on the furnace wall 1, and the movable nozzle 3 is moved forward and backward by the hydraulic cylinder 6 mounted on the pedestal 5. The gas is sent from the flexible preheating gas supply pipe 7 into the furnace. The sluice valve 8 can shut off the gas in the furnace atmosphere when the nozzle is repaired.

FIG. 2 is a schematic vertical sectional view of the oxygen blast furnace of the present invention, showing only the position of the movable nozzle in the height direction (the fixed nozzle is not shown).

The drive mechanism for the movable nozzle is omitted in FIGS. 1 and 2.

An example in which all of them are movable nozzles is shown in FIG.

FIG. 4 is a schematic diagram showing the operation flow of the oxygen blast furnace for carrying out the present invention. The top of the blast furnace 11 is the gas cleaning section 12.
Part of the gas is guided to the preheated gas combustor 15 via the booster 14 and burned by the gas from the oxygen source 16 to become high-temperature preheated gas from the preheated gas injection nozzle 19. It is blown into the furnace.

On the other hand, to the tuyere 17, oxygen from the oxygen source 16, the furnace top gas as the tuyere tip temperature adjusting gas passing through the booster 14 ', and the pulverized coal from the pulverized coal storage tank 18 are fed.

[Advantages of the Invention] As described in detail above, in the case of the present invention, not only the heat supply from the shaft portion is simply stopped, but also the temperature control of the core portion is insufficiently adjusted by the conventional fixed type preheating gas blowing nozzle. Therefore, it greatly contributes to the expansion of the reduction zone and the normalization of the furnace condition, which has a great effect on the reduction of the fuel ratio.

[Brief description of drawings]

FIG. 1 is a plan view (schematic diagram) showing an embodiment of a fixed gas blowing nozzle and a movable gas blowing nozzle used in the present invention. FIG. 2 is a vertical sectional view of the blast furnace of the present invention. FIG. 3 is a schematic view in which a movable nozzle having a hydraulic drive mechanism is installed on a shaft. FIG. 4 is a schematic diagram showing the flow of blast furnace operation in which the present invention is carried out. FIG. 5 is a schematic horizontal cross-sectional view when all the nozzles are movable. 1: Furnace wall 2: Fixed nozzle 3: Movable nozzle 4: Tuyer 5: Stand 6: Hydraulic cylinder 7: Preheating gas supply pipe 8: Gate valve 11: Blast furnace 12: Gas cleaning mechanism 13: Gas holder 14: Booster 14 ′: Booster 15: Preheated gas combustion device 16: Oxygen source 17: Tuyere 18: Pulverized coal storage tank 19: Preheated gas injection nozzle

Claims (1)

[Claims] 1. An oxygen blast furnace characterized in that a part or all of a plurality of preheating gas injection nozzles provided on a shaft portion can be moved forward and backward in the direction of the core.