JPH05202406A - Method for cooling vertical type smelting furnace - Google Patents

Abstract

PURPOSE:To improve the cooling efficiency of a vertical type smelting furnace and to obtain the stable operation by arranging a branched pipe in a circulating course of refrigeration water circulated between a furnace bottom and refrigeration, branching a part of the refrigeration water, supplying into tuyere part, etc., and cooling. CONSTITUTION:A cooling system to the tuyere part of the vertical type smelting furnace 1 pumps up the cooling water in a returned water vessel 3 by a returning water pump 2 and water pressure is risen by pumps 4, 5 and the water is fed to the tuyere barrel body and the tuyere tip part to execute the cooling, and drainage is returned to the returned water vessel 3. Further, the cooling of the furnace bottom 9 is executed by circulating the refrigeration water through the circulating course 10 connected with the refrigerator 8 and the furnace bottom 9. The branching pipe 11 is branched from this circulating course 10 and connected with supplying pipes 12, 13 into each tuyere in outlet sides of a tuyere barrel part pump 4 and a tuyere tip part pump 5 by three way gate valves 14, 15. Therefore, a part of the refrigeration water can be branched into the tuyere part and the tuyere part can effectively be cooled and further, a furnace side wall part and a stave, etc., can efficiently be cooled in the same method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cooling a vertical melting furnace such as a blast furnace, and more particularly to a method for cooling tuyeres and furnace side walls for protecting refractories in the furnace.

[0002]

2. Description of the Related Art In a vertical melting furnace, 11
By blowing hot air at a temperature of 00 ° C or higher into the furnace at a pressure of 2.5 to 4.5 kg / cm ² , the ore inserted from the top of the furnace is reduced, and the hot metal obtained by this is the furnace. It is stored in the hot water retention section at the bottom and is discharged out of the furnace from the tap hole in a timely manner.

In order to reduce the heat load and extend the life of the furnace body, the refractory material of the furnace body may be cooled by passing cooling water through a cooling board made of copper casting or a stave made of cast iron casting in the refractory layer. Or, it is designed to be cooled by sprinkling water directly on the outer steel shell, and most of the cooling water is either circulated or collected and reused, and the water temperature that rises due to reuse is lowered, It is used by replenishing new cooling water or exchanging heat with a heat exchanger using seawater as a refrigerant.

The refractory is constantly monitored during operation by a detecting means such as a thermocouple buried in the refractory. When the refractory temperature rises due to wear of the refractory, the amount of ore containing TiO ₂ is charged. The thickness of the solidified layer is increased to increase the supply of cooling water around the temperature rising point.
Increasing the amount of ore containing TiO ₂ is not preferable in terms of product quality because the amount of increase in Ti increases. Therefore, the method of increasing the amount of cooling water is usually adopted, but after taking such measures, if the refractory continues to wear and its temperature rises, the blowing of hot air is temporarily stopped to raise the temperature. Around this place, irregular shaped refractories were press-fitted, the tuyere diameter was reduced, the temperature immediately below was reduced, or the number of tapping was reduced to carry out a drastic production reduction operation.

[0005]

The cooling by the cooling water as described above requires a long period of time until the cooling effect appears, especially in the season when the water temperature rises such as in summer, and the addition of the cooling water or the seawater is required. The temperature drop of the cooling water due to heat exchange with is not expected in summer. In addition, when a hot spot where the temperature of the iron skin rises abnormally appears, not only a large amount of cooling water is required to intensively cool this area, but even if more cooling water is used, the water used in the factory There is a balance upper limit, and equipment such as cooling water supply, recovery, and water treatment measures will be enlarged.

If the cooling effect of the cooling water does not appear and the temperature continues to rise, temporary air blow is carried out. In this case, however, the production cost is reduced and the energy cost is increased due to the temperature drop in the furnace, resulting in irregular fire resistance. Press-fitting and tuyere reduction work also add considerable workload to operators. The present invention is intended to solve the above problems by enhancing the cooling effect of cooling water.

[0007]

According to the present invention, therefore, frozen water for cooling the bottom of a vertical melting furnace having a low water temperature cooled by a cooler can be used and supplied to a required cooling portion of the furnace body. It was done like this. That is, the present invention provides a branch pipe branched from the circulation path of the frozen water that circulates through the bottom of the vertical melting furnace and the refrigerator, and divides part of the frozen water cooled by the refrigerator when required. Supply to tuyere, cooling board embedded in refractory of furnace body, cooling device installed at the end of furnace for life extension (for example, Dussy cooler, water cooling plate, etc.), stave and / or nozzle for spraying iron shell It is characterized by being able to do so.

According to another aspect of the invention, a branch pipe is provided which branches from a circulation path of the frozen water circulating between the bottom of the vertical melting furnace and the refrigerator, and a part of the frozen water cooled by the refrigerator is separated. Then pass it through the radiator. Then, the cooling water cooled by using the frozen water as a refrigerant can be supplied to the tuyere, the cooling plate embedded in the refractory of the furnace body, the stave, and / or the nozzle for spraying water on the iron shell.

In the former invention, cooling which may be contaminated by dust or foreign matter while flowing down the iron skin and flowing out from the groove in the lower part of the furnace, such as frozen water sprinkled on the iron skin. In the system, the used cooling water is discarded as a temporary water, or is introduced into a sedimentation basin or the like to remove dust and foreign substances and then used as cooling water, or is sent to the refrigerator again and used as frozen water. To be reused. In this case, the depleted portion of the frozen water is newly replenished in the circulation path of the frozen water. on the other hand,
In a cooling system such as a tuyere, a cooling board, and a stave, it is desirable to configure the cooling system as a closed system and circulate the frozen water in order to prevent the frozen water from being contaminated with dust or foreign matter.

Also in the latter invention, the cooling system can be constructed as a closed system. In any case, the refrigerator is controlled so that the outlet water temperature of the frozen water is always constant so that cooling of the furnace bottom is not impaired.

[0011]

The cooling effect is enhanced by using frozen water or by using cooling water of a relatively low temperature obtained by cooling frozen water as a refrigerant, and the adhesion and growth of the melt on the refractory at the cooled location is promoted. The molten material and hot contents will not come into direct contact with the refractory material. As a result, the amount of cooling water used is reduced, the work required to lower the refractory temperature such as the injection of irregular-shaped refractory into the temperature rise area is reduced, and the furnace operation is stabilized.

[0012]

EXAMPLE FIG. 1 shows a cooling system for cooling the tuyere of a vertical melting furnace 1. A thin line in the figure is a conventional cooling system, and a thick line is branched from a circulating path of frozen water for cooling the furnace bottom. , A path for supplying frozen water to a conventional cooling system for cooling the tuyere. That is, in the conventional cooling system for cooling the tuyere, the cooling water pumped up from the return water tank 3 by the return water pump 2 is boosted by the tuyere body pump 4 and the tuyere tip pump 5 and the tuyere body of each tuyere. And the tip of the tuyere to cool each of these parts, and the cooling waste water that has cooled the tuyere body and the tip of the tuyere is returned to the return water tank 3 as shown by the dotted line in the figure, and the pump 2 Has been pumped up again and reused.

The frozen water for cooling the bottom of the furnace is circulated by the pump 7 through the circulation path 10 connecting the refrigerator 8 and the bottom 9 of the furnace, and the refrigerator 8 is cooled.
It is designed to cool the bottom 9 of the furnace after being cooled by, and the branch pipe 11 branched from the circulation path 10 is a supply pipe to each tuyere on the outlet side of the tuyere body pump 4 and the tuyere tip pump 5. 12 and 13 are three-way gate valves 14 and 1, respectively
5 are connected. 16 is a sluice valve.

In this embodiment, each tuyere is constantly cooled by the cooling water supplied from the cooling system indicated by the thin line during operation.
By monitoring the tuyere temperature with a thermocouple embedded in the tuyere,
When it is judged that a certain tuyere cannot withstand the heat load only by supplying the cooling water from the cooling system, the sluice valve 16 is opened and the three-way sluice valves 14 and 15 corresponding to the tuyere are operated. The branch pipe 11 and the supply pipes 12 and 13 are communicated with each other to switch to cooling water, and the frozen water cooled by the refrigerator 8 is sent to the tuyere body and the tuyere tip to cool each part. After cooling, this cooling water is returned to the return water tank 3 and is discarded when a certain amount or more is accumulated. However, depending on the water temperature, a part thereof is pumped up by the return water pump 2, and the tuyere body pump 4 and the tuyere tip pump. The pressure is increased at 5 and is sent to the tuyere body and the tip of the tuyere together with the frozen water, and is used to cool each part.

FIG. 2 shows the cooling system of the cooling plate 21 provided in the refractory of the furnace body and the cooling system for the iron shell. The thin line in the figure is the conventional cooling system, and the thick line is newly added. The supply route of frozen water is shown. That is, in the cooling system for the cooling plate, the cooling water whose pressure has been increased by the pump 22 is branched and sent to each cooling plate 21, and the refractory around it is cooled via each of the plurality of cooling plates, and then temporarily returned to the water tank 24. After being stored in a water tank 25 in the lower part of the furnace, it is pumped up by a pump 22 and reused.

In the cooling system for spraying the cooling water on the iron shell, the cooling water pumped up from the return water tank 27 and pressurized by the pump 28 is sent to the nozzle 29 arranged around the furnace and is sprayed on the iron shell by the nozzle 29. The cooling water that has traveled down the iron shell is once collected in the water tank 30 in the lower part of the furnace, and then returned to the return water tank 27 for reuse. The frozen water is supplied to the cooling system of the cooling board 21 and the cooling system for spraying the cooling water on the iron shell, by circulating the frozen water for cooling the furnace bottom 10
Is performed through branch pipes 32 and 33 that branch off from each other. Each of the branch pipes 32 and 33 is connected to a supply pipe 34 to the cooling plate 21 and a supply pipe 35 to the nozzle 29 by a three-way gate valve 36. It is connected so that frozen water can be supplied to the required cooling board 21 or nozzle 29 by operating the three-way gate valve 36. In the figure, 37 and 38 are gate valves.

Also in this embodiment, the cooling board 2 in the refractory is used.
Cooling water is constantly supplied to the nozzle 1 and the nozzle 29 to cool the refractory, but when the refractory temperature rises due to wear of the refractory and reaches a certain level, the three-way gate valve 36 is operated. The frozen water is supplied to the cooling platen 21 at or near the location, or the cooling water pumped up from the return water tank 24 is added to the frozen water and supplied. When a hot spot appears on the iron skin, the three-way gate valve 36 is operated to spray frozen water to the location. FIG. 3 shows the cooling system of the stave in the refractory. Cooling system,
The thick line indicates the supply path for supplying frozen water to the conventional cooling system of the stave. That is, in each of the staves 41 which are arranged in series in a vertical direction at a constant interval in the refractory of the furnace body, or are individually arranged, the pressure is increased by the pump 42 by the cooler 43. Cooled cooling water is supplied to cool the refractory, and the cooling water discharged from the stave 41 is once collected in the return water tank 44 and pumped by the pump 42 so as to circulate in the above-mentioned path. It has become.

The frozen water is supplied to the stave cooling system by branching from the circulating route 10 of the frozen water for cooling the furnace bottom.
It is carried out through a branch pipe 47 connected to the supply pipe 45 to the No. 1 by a three-way gate valve 46, and the operation of the three-way gate valve 46 switches the cooling water or the frozen water. Also in this embodiment, when the refractory temperature rises due to wear of the refractory, switching to the frozen water is performed by the switching operation of the three-way gate valve 46, and the frozen water is supplied to the stave. Even in this case, cooling water can be added to the stave and supplied.

In the above embodiment, a part of the frozen water for cooling the hearth is used to cool each part as it is. However, the cooling water should be used after cooling the frozen water as a refrigerant to lower the water temperature. You can FIG. 4 shows an example thereof, in which the frozen water branched from the circulating water 10 for cooling the furnace bottom is passed through the radiator 51, and the cooling water cooled by the frozen water in the radiator 51 is used as the nozzle 29. It is supplied to and sprayed on the iron skin. Although the frozen water that has left the radiator 51 is returned to the circulation path 10,
In order to improve the cooling effect, it may be supplied to the nozzle 29 and sprayed on the iron shell.

In each of the above embodiments, the cooling effect of the furnace bottom is not impaired by the use of frozen water.
The refrigerator 8 is controlled so that the outlet water temperature is constant. Although not shown in each of the above embodiments, a raw water supply pipe is connected to the circulation path of the frozen water to replenish the shortage caused by the use of the frozen water. As for cooling water, raw water can be replenished when a shortage occurs.

[0021]

The present invention is constructed as described above and has the following effects. According to the cooling method of claim 1,
Cooling is performed using frozen water for cooling the bottom of the furnace, which improves cooling efficiency and enables stable operation of the melting furnace. In addition, a large amount of cooling water is needed in case of an emergency when the temperature rises. It is possible to effectively use water resources, because it is not necessary to secure the above-mentioned requirement, equipment for that is not required, and the frequency of transient use of cooling water is reduced.

According to the cooling method of the second aspect, since the water temperature of the cooling water can be lowered, the cooling effect is improved and the same effect as described above can be obtained, and the frozen water is not consumed. Since it can be circulated and used, the circulation path can be a closed system and dust and foreign matter can be prevented from entering. According to the method of the third aspect, it is possible to always supply the frozen water having a constant temperature to the furnace bottom regardless of how the frozen water is used.

In the method according to the fourth aspect, it is possible to prevent dust or foreign matter from being mixed into the frozen water or the cooling water to contaminate them.

[Brief description of drawings]

FIG. 1 is a cooling water piping system diagram for cooling a tuyere.

FIG. 2 is a cooling water piping system diagram for cooling the side wall of the furnace.

FIG. 3 is a cooling water piping system diagram for cooling the stave.

FIG. 4 is a cooling water piping system diagram of another embodiment for cooling the side wall of the furnace.

[Explanation of sign]

1 ... Vertical melting furnace 2 ... Return water pump 3, 24, 27, 31, 44 ... Return water tank 4 ... Tuyere body pump 5 ... Tuyere tip pump 7, 22, 28 , 42 ... Pump 8 ... Refrigerator 9 ... Furnace bottom 10 ... Circulation path 11, 32, 33, 47 ... Branch pipe 12, 13, 34, 35, 45 ... Supply pipe 14, 15, 36, 46 ... 3-way gate valve 21 ... Cooling board 29 ... Nozzle 41 ... Stave 43 ... Cooler 51 ... Radiator

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Tamura, 11-11 Showa-cho, Kure-shi, Hiroshima Prefecture Kure Works, Nisshin Steel Co., Ltd. (72) Harushu Sasakawa 11-11, Showa-cho, Kure-shi, Hiroshima Nisshin Steel Co., Ltd.Kure Works (72) Inventor Mitsuo Fisherman 11-1 Showa-cho, Kure City, Hiroshima Prefecture Nisshin Steel Co., Ltd. Kure Works (72) Inventor, Hiroshi Kitaki 11-11 Showa-cho, Kure City, Hiroshima Prefecture No. 11 Kure Steel Works, Nisshin Steel Co., Ltd. (72) Inventor Shigeho Hogi 11-1 Showa-machi, Kure City, Hiroshima Prefecture Nisshin Steel Co., Ltd. Kure Works

Claims (4)

[Claims] 1. A branch pipe branching from a circulation path of frozen water circulating between a bottom of a vertical melting furnace and a refrigerator is provided, and a part of the frozen water cooled by the refrigerator is divided when required. A vertical melting furnace characterized by being able to supply to a tuyere, a cooling board embedded in the refractory of the furnace body, a cooling device installed at the end of the furnace, a stave, and / or a nozzle for watering the iron shell. Cooling method. 2. A branch pipe that branches from a circulation path of frozen water that circulates between the bottom of a vertical melting furnace and a refrigerator is provided, and a portion of the frozen water cooled by the refrigerator is divided into a radiator. Through
The radiator is characterized in that the cooling water cooled with the frozen water as a refrigerant can be supplied to the tuyere, the cooling board embedded in the refractory of the furnace body, the stave and / or the nozzle for watering the iron shell. Cooling method for vertical melting furnace. 3. The cooling method for a vertical melting furnace according to claim 1, wherein the refrigerator is controlled so that the outlet water temperature is kept constant. 4. Cooling of a vertical melting furnace according to claim 1, wherein the refrigerating water or the cooling water cooled by a radiator is circulated and used as a closed system. Method.