JPH0743216B2 - Operation method of double melting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an improvement in the operation method of a double melting facility for melting scraps, etc., and it is possible to reduce the product cost and improve the elasticity of operation by improving the utilization rate of nighttime power. It is intended to improve.

[Conventional technology]

For steelmaking performed by melting scrap (scrap iron), a melting facility using an electric furnace is generally used. In this electric furnace melting equipment, the raw material scrap is charged into the furnace body, melted by arc heat, tapped, the refractory on the inside of the furnace is repaired after tapping, and the raw material is charged again. Is operated.

In order to shorten the cycle of such operations, 2 units 1
A dual electric facility that installs a pair of furnace bodies and prepares for operation in one furnace body while the other furnace body is operating, and preheats using the high-temperature waste gas generated in the operating furnace body It is being used.

[Problems to be solved by the invention]

By using such a double electric furnace facility, the operating cycle is shortened and the heat energy is recovered, but most of the steelmaking cost is determined by the electric power amount, and in order to reduce the steelmaking cost, the electric power cost is reduced. It is necessary to reduce

This power cost differs between daytime and nighttime, and effective use of nighttime power can reduce steelmaking costs.However, conventional dual electric furnace facilities use a large amount of nighttime power to generate a large amount of power in a short time. Even if the molten metal was produced, it was not possible to increase the utilization rate of night-time electric power due to restrictions in the capacity of the subsequent ingot making process.

In addition, in the conventional double electric furnace equipment, there is a problem that the equipment or operation is lacking in elasticity because it is not possible to quickly perform hot water return, which requires a return of the molten metal due to a trouble in the ingot making process or the like.

The present invention has been made in view of the above prior art, and it is an object of the present invention to provide a method for operating a double melting facility capable of effectively utilizing nighttime electric power for melting and flexibly responding to a trouble in a post process. To do.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention adds two pairs of furnace bodies which are alternately in operation and standby preheating to the above-mentioned two.
A third furnace body capable of storing a larger amount of molten metal than the storage capacity of a pair of base furnace bodies, and can be shared by these three furnace bodies 1
Using a double melting system consisting of a power supply unit, two furnace pairs of two furnaces use full electric power to melt by repeating the operation and standby preheating during the night when the electricity rate is low. Heat is retained while sequentially storing extra molten metal in the third furnace body in the subsequent process, and the melting of the two furnace bodies in the operating side is completed in a pair of two furnace bodies during the time when the electricity charge is high. Immediately before, melting heating is performed using the heat obtained by supplying a predetermined amount of the molten metal stored in the third furnace body to the furnace body on the standby preheating side as an auxiliary, and this melting heating causes the excess power of the melting power supply device to be exceeded. It is characterized in that the molten metal stored in the third furnace body is heat-retained with such ability.

[Work]

A third furnace body that can store a large amount of molten metal by brass is installed in a pair of two furnace bodies that are operated alternately, and the electric power is fully used during the night when the electricity rate is low. The excess molten metal is then stored, and the molten metal is effectively used during periods of high electricity charges to reduce steelmaking costs, and the molten metal storage function improves the elasticity of operation.

〔Example〕

An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a plan view showing a schematic configuration of an embodiment of the double melting equipment of the present invention.

The double melting equipment 10 includes two pairs of melting furnace bodies 11 and 12 which are alternately used for the operation side and the standby preheating side and are used. A furnace body 13 for storing the molten metal is installed in the middle, and these three furnace bodies 11, 12, 13 are arranged on the same circumference.

The molten metal storage furnace body 13 is for storing excess molten metal more than the molten metal used in the subsequent process, and the melting furnace bodies 11 and 12 are used.
5 to 10 times the capacity is used.

These three furnace bodies 11, 12, 13 are installed in the center of the three furnace bodies so that one melting power supply device 14 can be shared, and each of the furnace bodies 11, 12, 13 has a An electrode hole 16 for inserting the electrode 15 is formed. These electrodes 15 are connected to a reactor transformer 19 via a secondary side conductor 17 and a power feeding flexible cable 18.
In addition, it is possible to pivotally move to any one of the predetermined furnace bodies 11, 12, 13 by an electrode elevating mechanism and an electrode moving mechanism (not shown).

In the scrap melting operation according to the operation method of the double melting equipment 10 configured as described above, first, one of the melting furnaces 11, 12 is set as the operating side, and the other furnace body 12 is in standby preheating. To the side.

In the furnace body 11 on the operation side, scrap is charged into the furnace, the electrode 15 is inserted into the electrode hole 16 and melting is performed by arc heat, and the other furnace body 12 is provided for the next operation. The charged scrap is preheated by the high-temperature waste gas from the furnace body 11 on the operating side. (The exhaust gas duct connecting the two furnace bodies is not shown.) And, immediately before the melting in the furnace body 11 on the operating side is completed, a predetermined amount of the molten metal stored in the furnace body 13 for storing molten metal is supplied to the standby preheating side. It is supplied to the furnace body 12 and heating using a part of the molten metal is started. In this case, tapping from the furnace body 13 for storing molten metal may be performed in the same manner as in the conventional method such as tilting the furnace body 13, and a gutter may be used to supply the molten metal to the furnace body 12 on the standby preheating side. , It can be done by using a ladle.

After this, when the melting in the furnace body 11 on the operation side is completed, the electrode moving mechanism or the like immediately swivels the electrode 15, the secondary conductor 17, etc. to the furnace body 12 on the standby preheating side to start the operation. In the furnace body 12 that has been switched from the standby preheating side to the operation side, in addition to the preheating by the high-temperature waste gas, a part of the molten metal is supplied from the molten metal storage furnace body 13, so that the arc heat generated by the electrode 15 generates electric power. It is not necessary to supply it as full power, and it is possible to operate with the melting power supply device 14 having a sufficient margin. Therefore, the molten power stored in the molten metal storage furnace body 13 is kept warm by appropriately using the melting power source device during the melting operation of the furnace body 12.

By repeating such operations, standby preheating, and partial supply of molten metal alternately, operations are carried out during the daytime and other high electricity rate hours.

On the other hand, during nights and other times when the electricity rate is low, the electric power is fully used for the subsequent process regardless of the amount of tap water, and the melting capacity of the two melting furnace bodies 11 and 12 is fully used for scrap. Is melted, and excess melt is stored in the furnace body 13 for storing melt.
In the case of this molten metal storage, since high temperature molten metal is gradually added in accordance with the melting cycle, it is not necessary to heat the furnace body 13 to keep it warm, and the melting power supply device 14 can be used only for melting. .

In this way, the furnace body 13 for storing molten metal is filled with the molten metal during the time when the electricity rate is low, and is used in the daytime and the like.

In the above embodiment, the case where the melting furnace body is a three-phase AC arc furnace has been described, but the present invention is not limited to this, and can be widely applied to furnace bodies that melt by electric power such as a DC arc furnace and a plasma furnace.

〔The invention's effect〕

According to the present invention as specifically described with reference to the above-mentioned one embodiment, a third furnace body for storing molten metal is installed in addition to a pair of melting furnace bodies that are alternately operated. These 3
Since the single melting power supply device can be shared by the base furnace body, the following effects can be obtained.

During times of low electricity rates, such as at night, you can use the full amount of electricity to melt and store excess molten metal.
It is possible to perform melting operation using the stored molten metal at a time when the electricity rate is high without using much electric power, and it is possible to reduce the melting cost by improving the nighttime power utilization rate.

By the operation of using a part of the stored molten metal, the number of times of charging the scrap can be reduced, the heat release due to the opening and closing of the scrap charging port (generally, the furnace lid) is reduced, and the thermal efficiency is improved.

Since the same melting power source device as the melting furnace body is shared for heat retention of the molten metal storage furnace body, there is no need to provide a separate heat-retaining facility, which is economical.

Even if trouble occurs in the post-melting process such as the stand block process, the molten metal can be stored, so it is not necessary to stop the operation, and hot water can be easily returned by returning it to the furnace for storage. The elasticity of the operation of is improved.

Even when carrying out an operation method in which carbon material, oxygen, etc. are blown into the molten metal in combination with melting by electric power to dissolve scrap, the stored molten metal can be used as the initial molten metal and it is necessary to operate while leaving the residual molten metal. There is no such problem, and at the same time when the operation starts, the carbonaceous materials and oxygen are blown and melted, resulting in significant power savings and operational efficiency.

[Brief description of drawings]

FIG. 1 is a plan view showing a schematic configuration according to an embodiment of the double melting equipment of the present invention. 10 …… Complex melting equipment, 11 …… Operating side furnace body, 12 …… Standby preheating side furnace body, 13 …… Molten metal storage furnace body, 14 …… Melting power supply device, 15 …… Electrodes, 16… … Electrode hole, 17 …… Secondary conductor, 18 …… Flexible cable for feeding, 19 …… Transformer for furnace.

Claims (1)

[Claims] 1. A third furnace body capable of accumulating a larger amount of molten metal than the storage amount of the pair of furnace bodies in addition to the pair of furnace bodies alternately operating and standby preheating. Also, by using a double melting equipment consisting of one melting power supply device that can be shared by these three furnace bodies, two pairs of furnace bodies use full power during nighttime and low electricity rates. The operation and standby preheating are repeated to melt, and heat is retained while sequentially storing excess molten metal in the third process in the subsequent process. Immediately before the melting in the furnace body on the operation side is completed, a predetermined amount of the molten metal stored in the third furnace body is supplied to the furnace body on the standby preheating side to perform melting and heating using the heat as an auxiliary. By this melting and heating, the remaining capacity of the melting power source device is stored in the third furnace body. Operating method of the dual melting equipment which is characterized in that the hot water heat-keeping.