JPH0421709A - Method of cooling with water pouring for remaining charged material in furnace at the time of blowing down operation in empty blast furnace - Google Patents

Abstract

PURPOSE:To safely cool remaining charged material in a furnace with water spraying in a short time at the time of blowing stop in the blast furnace by spraying cooling water from the upper part after the remaining charged material in the furnace lowers to a tuyere level, and further, pouring the cooling water into the furnace through an iron tapping hole at the suitable time. CONSTITUTION:At the time of blowing stop in the blast furnace, the raw material charge to the blast furnace 1 is stopped and, on the other hand, the blasting from tuyeres 3 is continued and the charged material in the furnace is melted and discharged in order, and the charged material level is lowered to be the empty furnace condition. At the time of blowing down operation into the empty blast furnace condition, the remaining charged material 2 in the furnace is cooled by pouring the cooling water. At this time, after height of this remaining charged material 2 in the furnace lowers to the tuyere level 3, the blasting is stopped. Successively, the cooling water 5 is sprayed from the upper part through a water supply piping 4 to cool the remaining charged material 2. At the time, when the above cooling water begins to flow out of the furnace from the iron tapping hole 8 or when the temp. lowers to the prescribed temp., the cooling water is poured through the iron tapping hole 8. This water pouring is desirable to execute by parting with a blind plate 10 between a gun barrel 9a of mud gun 9 and tip part 9b thereof while pushing the tip part 9b to the iron tapping hole 8. By this method, shortening of water cooling time and securing of safety are obtd.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for injecting water into a blast furnace to cool the charge remaining in the blast furnace during blow-down. The aim is to shorten water injection cooling time and ensure safety.

<Conventional technique> Stopping the operation of a blast furnace is called blowdown, and blowdown is performed when the blast furnace is renovated.When the furnace body is worn out or the auxiliary equipment becomes obsolete, blast furnaces are used for equipment improvement or new technology. A so-called renovation will be carried out by introducing the following.

During blast furnace operation, ore and coke are charged into the furnace in layers, whereas during blowdown, only coke is charged without ore. Starting with coke replacement work, temporary tapping work from the bottom of the furnace, gas shutoff, ventilation stoppage, and water injection cooling! #Preparation work: cooling the coke in the furnace by injecting cooling water from the top of the furnace, and discharging the coke in the furnace (for example, in Japanese Patent Application Laid-Open No. 1983-1999)
137803 and Japanese Unexamined Patent Publication No. 58-27911).

However, the above-mentioned method not only takes time to replace the coke and cool it, but also requires time and effort to scrape out the coke, which poses problems in terms of repair work period and cost. Therefore, in order to shorten the renovation work period, the contents in the blast furnace are lowered to the tuyere level without replacing them with coke during operation, and the air blowing is stopped at this stage. The red-hot coke remaining in the lower part of the furnace was
An improvement has been made in which the remaining charges such as semi-molten pig iron and slag are injected with cooling water to cool them down, and then the remaining charges in the furnace are discharged (Japanese Patent Laid-Open No. 57-171606, Showa 5
8-9004, JP-A-58-104104).

In other words, Japanese Patent Application Laid-Open No. 57-171606 discloses that after the charge in the reactor is reduced to the level of the tuyere, cooling water is injected from the tuyere to remove the remaining charge in the reactor from the periphery to the lower part. JP-A No. 58-9004 discloses a method in which cooling is performed sequentially from the bottom to the top, and in Japanese Patent Application Laid-Open No. 58-9004, an injection port is provided slightly below the tuyere, and high-pressure water is injected from this to remove the residual equipment in the reactor. A method has been proposed in which the charged material is cooled and drained from the tap hole, etc., and Japanese Patent Application Laid-Open No. 172606/1983 describes a system in which the reduced size of the remaining charge in the furnace is cooled by sprinkling water from the top of the furnace. A method is disclosed.

<Problems to be Solved by the Invention> However, the reduced size blowing method described in the above-mentioned publication involves spraying, water injection, or high pressure cooling water from above the remaining charge in the furnace whose size has been reduced by blowing down the air furnace. Since water is injected to cool the reactor, most of the cooling water flows over the surface of the charge remaining in the reactor, and only the surface layer is cooled, and it takes a long time to cool the entire reactor. In particular, there is a strong tendency for the cooling water to flow concentrated only in the passageways formed when it flows over the surface of the remaining charge in the reactor, further reducing the cooling effect.

Therefore, in order to inject cooling water into the interior of the remaining charges in the reactor, there were problems such as the need to separately provide a cooling water supply valve and a cooling water supply device.

The present invention solves the problems of the prior art described above, and enables the residual charge in the furnace, which has been reduced in size to the grain level, to be safely and quickly cooled by cooling water during the blow-down operation of a blast furnace. The purpose of this invention is to provide a method for cooling residual charge in a reactor by injecting water into the reactor.

<Means for Solving the Problems> The present invention to achieve the above-mentioned object is to stop the charging of raw materials into the blast furnace, while continuing to blow air from the tuyeres to sequentially melt the contents in the furnace. In a water injection cooling method for residual charge in a blast furnace during an air blow-down operation of a blast furnace, the charge level is lowered and discharged to reduce the level of the charge to an empty furnace state. After the air is reduced down to the tuyere level, the air blowing is stopped, and then cooling water is sprayed from above the charge remaining in the reactor to cool it down, and as the sprayed cooling water evaporates, the charge remaining in the reactor is reduced. When the cooling water flows down through the charge and begins to flow out of the furnace from the taphole located below the tuyeres, or when the temperature of the flowing cooling water has decreased to a predetermined temperature, A blast furnace characterized in that cooling water is injected into the furnace through the pigtail hole, and as the injected cooling water evaporates, the water level accumulated at the bottom of the furnace rises, and the cooling water is discharged from the tuyere to the outside of the furnace. This is a water injection cooling method for the remaining charge in the furnace during air blowdown operation.

In order to inject cooling water into the furnace through the taphole, a blind plate is used to partition the barrel and the tip of the cloak gun, a water supply pipe is connected to the tip, and the tip of the 77-gun is tapped. After the tap is pressed, it is preferable to supply cooling water from the water supply pipe and inject the water into the furnace through the taphole.

Action〉 The air furnace is blown down to the tuyere level, and the remaining charge in the furnace is sprinkled with water from above.This watering can be done either by watering from a watering pipe from the top of the furnace or from the tuyere. Ideally, the remaining charge should be cooled from the surface layer to prevent an explosion inside the furnace.

In the past, the remaining charge in the reactor was only cooled by water spraying from above, but in the present invention, the cooling water is evaporated by contact with the red-hot remaining charge in the reactor during the above-mentioned water spray cooling process. As cooling progresses, cooling water flows down through the remaining charge. Thus, when the cooling water starts to be discharged outside the furnace from the taphole disposed below the tuyeres, the injection of cooling water through the taphole starts.

The reason for first spraying water to cool the remaining charge in the furnace from above is to prevent steam explosions caused by contact between cooling water and molten metal such as hot metal by gradually cooling the remaining charge in the furnace from the top. . The reason for switching to water injection cooling from the taphole is to wait for the cooling water sprayed to be discharged from the taphole because at this point, there is no longer any molten material mixed in the remaining charge in the furnace. . In the cooling stage by water injection from the taphole, the remaining charge in the furnace, which has a large heat capacity, is quickly and safely cooled by steam rising from the bottom of the furnace and cooling water pooled at the bottom of the furnace. Rapid cooling is achieved by drainage from the mouth.

The same applies to the case where water injection cooling from the taphole is started according to the temperature of the cooling water discharged from the taphole due to water cooling, and when the water temperature reaches a predetermined temperature, for example, 80°C, the tapping is started. Start supplying cooling water from the mouth.

Hereinafter, the configuration of the present invention will be explained in detail based on the drawings. As shown in FIG. 1(A), while the charging of raw materials such as ore and coke into the blast furnace is stopped, the tuyere 3 is
Continue blowing air from the furnace to sequentially melt the contents in the furnace, discharge the hot metal and slag from the tap hole 8, lower the level of the charge to the level of the tuyere 3, and reduce the remaining charge in the furnace. After the container 2 is formed, the air blowing is stopped. In addition, when blowing down the air furnace, tap hole 8
If this happens, it will be a problem, so when stopping the blow, it is preferable to blow oxygen from the tap hole 8 to ensure an opening into the furnace.

Thereafter, a water supply pipe 4 is inserted into the furnace from the top of the furnace, and cooling water 5 is sprinkled from the water supply pipe 4 to cool the surface layer of the charge 2 remaining in the furnace below. The sprayed cooling water evaporates into steam when it comes into contact with the red-hot residual charge 2 in the reactor, but as cooling progresses, it flows down while passing through the residual charge 2 as shown by the dotted arrow in the drawing. However, during the cooking process, the remaining charge 2 reaches the bottom.

In such a water spray cooling process, molten materials such as hot metal and slag mixed in the residual charge 2 are cooled without causing a steam explosion. After passing through the residual charge 2 in this way, the taphole 8 is opened at the time when the discharge from the taphole 8 is started or when the temperature of the cooling water discharged from the taphole has decreased to, for example, 80°C. Start injecting cooling water through the

A water supply pipe (
(not shown) can be inserted into the taphole 8 to supply water, but it is necessary to seal the gap between the taphole 8 and the water supply pipe with a sealing material, which takes time and effort. Become. Therefore, in order to suitably carry out the method of the present invention, a mud gun 9 that closes the tap hole 8 is used as shown in FIG. A blind plate 10 is interposed to partition the pipe, and a water supply pipe 11 is connected to the pipe tip 9b to supply water.

When water is supplied through the taphole 8, the tip 9b of the mud gun 9 is first strongly pressed against the outer surface of the taphole 8 to bring it into close contact, and then when water is started to be supplied from the water supply pipe 11, the mudgun 9 is partitioned off by a blind plate lO. Therefore, the cooling water is injected into the furnace from the pipe tip 9b through the tap hole 8 without flowing backward.

In the cooling stage by water injection from the taphole 8, the remaining charge 2 in the furnace, which has a large heat capacity, is quickly and safely cooled from the bottom to the top by the steam rising from the bottom of the furnace and the cooling water pooled at the bottom of the furnace. , the remaining charge 2 in the furnace is cooled to the upper part by the water discharge 6 from the tuyere 3 due to the water level rising upward as shown by the solid arrow.

In the above-mentioned configuration, the residual charge 2 in the furnace is cooled by water spraying using the water supply pipe 4 inserted into the top of the furnace. Similar effects can be obtained by cooling the container 4 with water.

<Example> Example I Furnace internal volume 3000 to 4000 rr? When blowing down a high-grade blast furnace, it takes 2.5 to 3 days to complete cooling if the conventional method of cooling the contents in the furnace, which has been reduced to the tuyere level, is consistently sprayed with water from the top of the furnace. However, when blowing down the furnace, oxygen was blown into the taphole to ensure an opening extending from the taphole to 3 to 6m inside the furnace. Subsequently, water was sprayed from the top of the furnace to begin cooling the remaining charge inside the furnace. Approximately one day after the start of water spray cooling, drainage from the taphole was observed, so from this stage cooling water was supplied from the tip of the mud gun partitioned by a blind plate and into the furnace through the taphole. Water was injected and used in conjunction with water sprinkling from the top of the furnace to cool the remaining charge inside the furnace. Cooling water was discharged through the tuyere, and cooling work was completed without any trouble when the temperature of the drain water reached 50°C after about 20 hours.

Example 2 When blowing down the air furnace to the same rod as in Example 7, approximately one day had passed after the start of cooling with water sprinkled from the top of the furnace, and when the temperature of the waste water had decreased to 80'C, cooling was started from the tip of the cape gun. Water was supplied and injected into the furnace through the tap hole, and was used in combination with water sprinkling from the top of the furnace to cool the remaining charge in the furnace. After about 25 hours, when the temperature of the wastewater reached 50'C, the cooling operation could be completed without any trouble, as in Example 1.

<Effects of the Invention> As explained above, according to the present invention, the work of cooling the remaining charge in the blast furnace using cooling water by blowing down the blast furnace can be completed quickly without causing troubles such as water agitation. As a result, the blast furnace refurbishment period can be shortened.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing the water injection cooling method of the present invention. ■... Furnace body, 2... Remaining charge in the furnace, 3
...Win, 5...Cooling water, 7...Annular pipe, 9...Mud gun, 11...Water supply pipe. 4...Water supply piping, 6...Drainage, 8...Tapping port, lO...Blind plate,

Claims (1)

[Claims] 1. While stopping the charging of raw materials into the blast furnace, air is continued to be blown from the tuyere to sequentially melt and discharge the contents in the furnace, and the level of the charged materials is lowered and reduced. In a water injection cooling method for residual charge in a blast furnace during an air blowdown operation of a blast furnace, which leads to an empty furnace state,
After the height of the residual charge in the furnace is reduced down to the tuyere level, the blowing of air is stopped, and then cooling water is sprinkled from above the residual charge in the furnace to cool it, and the water is sprayed. The cooling water flows down through the remaining charge inside the furnace while evaporating, and when it starts to flow out of the furnace from the taphole located below the tuyere, or when the temperature of the flowing cooling water reaches a predetermined value. When the temperature has dropped to the same temperature, cooling water is injected into the furnace through the taphole, and as the injected cooling water evaporates, the water level accumulated at the bottom of the furnace rises, causing cooling water to flow out of the furnace from the tuyeres. A method for cooling residual charge in a blast furnace by injecting water into the blast furnace during air blow-down operation, characterized by discharging the charge. 2. Separate the barrel and tip of the mud gun with a blind plate, connect a water supply pipe to the tip, press the tip of the mud gun against the taphole, supply cooling water from the water supply pipe, and tap the taphole. Claim 1 comprising injecting water into the furnace through the pigtail hole.
Method described.