JPS63171811A - Operation of oxygen blast furnace - Google Patents

Abstract

PURPOSE:To stably and smoothly operate an oxygen blast furnace, by blowing fuel from a fuel feeding system attached to a water-cooled tuyere fixed in the wall of the blast furnace when the amt. of pulverized coal blown from the tuyere decreases to a prescribed value or below. CONSTITUTION:A burner 1 is inserted in a water-cooled tuyere 10 fixed in the wall brick 11 of an oxygen blast furnace. Pulverized coal is blown from the blowing hole 2 of the inner tube 3 of the burner 1, oxygen and steam are fed from the oxygen blowing region 4 of the burner 1 and a steam feeding pipe 7, respectively, and the blast furnace is operated. When the amt. of the pulverized coal blown from the hole 2 decreases to a prescribed value or below, an automatic controlling mechanism is worked to gradually feed C gas from a C gas feeding pipe 8 or heavy oil from a heavy oil feeding pipe 9. Thus, the blast furnace is stably operated without considerably changing the conditions of the furnace.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an oxygen blast furnace, particularly a method of operating an oxygen blast furnace using pulverized coal.

(Prior art) Most of the practical blast furnaces currently in operation do not carry out some oxygen enrichment, but the amount of air blown from the tuyeres is 1,000 to 1
Since the air is at 300℃, 08 during ventilation is 21-30%
Therefore, a part of the coke as a reducing agent is replaced with pulverized coal, and the amount injected through the tuyeres is also approximately limited to 100 kg/T. However, in recent years, in order to further improve the productivity of blast furnaces, operation of oxygen blast furnaces has been proposed. A recent example is JP-A-60-159104, in which oxygen is blown into the tuyere. In the embodiment of this invention, 100k
Pulverized coal is injected at a rate of approximately 200 to 30 g/T, but in the case of an oxygen blast furnace, the highest oxygen concentration at the tuyere tip reaches about three times that of conventional methods, so the amount of pulverized coal used at the tuyere tip is also 200 to 30 g/T.
It is possible to use up to 0 Nigi/T. However, even with conventional blast furnace operating methods, if the supply of pulverized coal is temporarily stopped due to a problem with the pulverized coal injection device, the temperature at the tip of the tuyere and the heat balance inside the furnace will change considerably, so C gas or Backing up with heavy oil has been proposed. In other words, if troubles in the pulverized coal injection equipment are expected to last for a long time, the blowing pressure of the blast furnace may be increased from the usual 3 to 4 kg/crA to 0.5 to 1 crA.
kg/cd, the lance for injecting pulverized coal into the tuyeres is pulled out, and the lance for injecting heavy oil or C gas is inserted and set to inject heavy oil, etc.

(Problem to be Solved by the Invention) However, in the case of the above-mentioned oxygen blast furnace, the amount of pulverized coal injected is considerably high, and the amount of reducing agent required for blast furnace operation is reduced to about half. Therefore, the effects of troubles in the pulverized coal injection system are warmer and more rapid than those in conventional conventional blast furnaces, causing large fluctuations in the reduction reaction inside the furnace. . If you limit the blowing pressure, pull out the lance, insert a new lance for injecting heavy oil, etc., and then inject C gas or heavy oil, this will inevitably cause severe disruption to the operation of the oxygen blast furnace. do not have.

It is also possible to inject the above-mentioned heavy oil or C gas using the pulverized coal injection pipe, but in the case of heavy oil, it is necessary to restart the supply of pulverized coal after the failure in the pulverized coal supply system is recovered. There are disadvantages that leave a negative impact.

"Structure of the Invention" (Means for Solving the Problems) The present invention was created after repeated studies to solve the problems of the conventional products as described above, and includes an oxygen-pulverized coal burner. In the operation of an oxygen blast furnace using a blast furnace tuyere, a pulverized coal inlet is formed in the burner body, which can be charged into the water-cooled tuyeres provided on the blast furnace wall, and a fuel supply system is connected to the burner body. The pulverized coal injection port is also equipped with a blown gas pipe connected to the pulverized coal injection port, and when the amount of supply from the pulverized coal injection port falls below a predetermined value, fuel is injected from the fuel supply system to continue the operation. How to operate an oxygen blast furnace.

(Function) In the present invention, an oxygen blast furnace refers to an oxygen concentration of 40% from the surface.
This is a blast furnace that operates by blowing the above-mentioned gas at room temperature and preheating gas from a shaft.

When operating an oxygen blast furnace, pulverized coal is injected by forming a pulverized coal injection area by surrounding a pulverized coal inlet in a burner body that can be charged into a water-cooled tuyere, and mixing pulverized coal with 0□. The pulverized coal is effectively ignited and combusted immediately after it is blown into the furnace from the burner. In addition, by inserting the burner body into the water-cooled tuyere, the opening of the burner body into the furnace is protected and stable blowing can be achieved.

By preparing the burner body with an blown gas pipe connected to a fuel supply system, the tuyere tip temperature adjusting gas can be used to operate the oxygen blast furnace that injects pulverized coal as described above. is introduced through this blown gas pipe to maintain stable operation with a constant temperature at the tip of the tuyere. Moreover, in the event of a problem with the pulverized coal suction system where the supply amount from the pulverized coal inlet is below a predetermined value, the burner body can be left set to the water-cooled tuyere and the above-mentioned fuel supply system can be replaced with C gas, heavy oil, etc. By supplying and injecting one or both of them, it is possible to continue operating the oxygen blast furnace by injecting the fuel immediately after a trouble occurs.

That is, even if an abnormality occurs in the pulverized coal supply system of the oxygen blast furnace and coal feeding is stopped, operation can be appropriately continued with the fluctuations in furnace conditions kept to a minimum.

When applying the present invention, it is clear that it is important to decide when to switch over to C gas as the first step, but normally during blast furnace operation, pulverized coal is changed based on various data from inside the furnace. The supply amount is automatically controlled between 80 and 120 per unit time, assuming the average is 100.
If the upper and lower limits are exceeded continuously for a certain period of time, an alarm will sound and operation should be carried out with caution, and if the lower limit danger line is suddenly exceeded, the pulverized coal supply valve will be closed by an automatic switching device and the C gas It is preferable to set an automatic control mechanism to open the supply valve in advance. In other words, by doing this, it is possible to quickly confirm the cause of failure, estimate recovery time, change in furnace status, and confirm supply and demand of C gas. Unravel in time,
A pre-calculated amount of C gas or heavy oil (heavy oil or tar) corresponding to a pre-calculated amount of pulverized coal can be fed to the siding or near the tuyeres. As mentioned above, if both C gas and heavy oil are supplied through the same pipe as the pulverized coal supply pipe, this will have an adverse effect on the supply of pulverized coal after recovery from a failure.

(Embodiment) In the present invention, as shown in FIG. 1, a burner body 1 that can be set by being inserted into a water-cooled tuyere 10 provided in a furnace brick 11 is shown in detail in FIG. 2. Prepare a configuration like this. That is, an oxygen blowing region 4 is formed surrounding the burner inner cylinder 3 that forms the pulverized coal blowing ports 2, and these blowing ports 2
and a small tuyere body 5 provided on the front end side of the oxygen blowing area 4
A blown gas pipe line 6 is connected thereto. Further, a steam supply pipe 7, a C gas supply pipe 8 and a heavy oil supply pipe 9 are respectively connected to this blown gas pipe 6, and these supply pipes 7.8
．． Each of the flow valves 9 is provided with a regulating valve 15, a solenoid valve 16, a manual stop valve 17, etc. to control the supply thereof.

For example, in an oxygen blast furnace with a tapping rate of 5,000 T/day, Ot is 290 kg/T under charging conditions of a coke ratio of 350 kg/T.
According to the standard conditions of 200 kg/T of pulverized coal and 2 kg/T of steam from the supply pipe 7, 0! Oxygen injection area 4 as mentioned above, pulverized coal 690kg/wi
Automatic control is performed when the amount of pulverized coal injected from the burner inner cylinder decreases from 690 kg/min to zero while operating by blowing steam into the burner inner cylinder 3 at a rate of n. The system was operated to gradually supply coke gas and finally inject it at 1100 N rrr/min. As a result, stable operation was achieved without causing any major fluctuations in the furnace conditions in the oxygen blast furnace.

"Effects of the Invention" The present invention as explained above has advantages in terms of equipment and operation, such as injecting pulverized coal in a large amount, which is about half of the amount of reducing agent required for blast furnace operation. When operating an oxygen blast furnace, it is possible to effectively deal with unavoidable troubles in the important pulverized coal injection charging system, and to smoothly and stably operate the oxygen blast furnace. This invention is industrially very effective.

[Brief explanation of the drawing]

The drawings show the technical contents of the present invention, and FIG. 1 is a cross-sectional view showing the general relationship of equipment for implementing the present invention, and FIG. 2 is a cut-away side view of the burner body. be. However, in these drawings, ■ is the burner body, 2 is the pulverized coal inlet, 3 is the burner inner cylinder, 4 is the oxygen blowing area, 5 is the small tuyere body, 6 is the blown gas tube furnace, and 7 is the steam supply pipe. , 8 is C
A gas supply pipe, 9 a heavy oil supply pipe, 10 a water-cooled tuyere, 11 a furnace brick, 15 a flow rate adjustment valve, 16 a solenoid valve, and 17 a manual stop valve.

Claims (1)

[Claims] In the operation of an oxygen blast furnace using a blast furnace tuyere containing an oxygen-pulverized coal burner, an O_
2. A blowing gas pipe line is prepared which forms two blowing areas and is connected to a fuel supply system, and when the supply amount from the pulverized coal injection port becomes less than a predetermined value, A method of operating an oxygen blast furnace characterized by continuing operation by injecting fuel.