JPH07803B2 - Exhaust gas heat recovery method for dual melting furnace - Google Patents

Description

The present invention relates to a melting furnace for melting scrap, and more particularly to a melting furnace for melting scrap.
The present invention relates to an exhaust gas heat recovery method for a dual melting furnace having a pair of base furnaces.

[Conventional technology]

Conventionally, as a double melting furnace having a pair of two furnaces, the exhaust gas generated in the operating side shell is introduced into the standby side shell to preheat the scrap charged in the standby side shell. Steelmaking facilities (Japanese Patent Publication No. 59-47831 and Japanese Patent Publication No. 48-45937) have been proposed.

By operating as described above, repairing after tapping,
It is said that it is possible to eliminate the idle time from charging the raw materials to turning on the power, and to shorten the melting time because the scrap in the furnace on the side of the operation is preheated by the exhaust gas.

[Problems to be solved by the invention]

In the above-mentioned conventional double melting furnace, the entire amount of exhaust gas is simply introduced from the operating side shell into the standby side shell, so after passing through the standby side shell, the exhaust gas is discharged as it is. As a result, the exhaust gas energy cannot be sufficiently recovered, and the odor generated from the raw material preheated in the standby side furnace shell will remain in the atmosphere unless separate deodorizing equipment is installed. Will be released into the air and will disperse the foul odor. For this reason, there is a drawback that the raw materials to be handled are limited to those that do not contain odor. Further, when a large amount of unburned gas is contained in the exhaust gas, there is a problem that the recovery efficiency of heat energy is further reduced.

[Means for solving problems]

In order to solve the above-mentioned problems of the prior art, in the present invention, a pair of two melting furnaces, one of which is an operating side and the other of which is a raw material preheating side, and a melting shell for communicating with each of these A double-sided melting furnace having an initial molten metal supply furnace shell for supplying an initial molten metal for injecting fuel, the operating side being installed in an exhaust gas duct connecting the two melting furnace shells. High temperature combustion gas obtained by burning the unburned gas in the exhaust gas of the melting furnace of the operating side in the combustion tube with a combustion tube that burns the unburned gas in the exhaust gas from the furnace shell for melting Is introduced into the furnace shell on the preheating side through the exhaust gas duct, and the raw material in the furnace shell for melting on the preheating side is preheated, and the exhaust gas after the preheating is used to melt the initial molten metal in the initial molten metal supply furnace shell. Introduced into the interior of the exhaust gas to thermally decompose the odorous components in the exhaust gas and exhaust it. Is shall.

[Action]

By adopting the above method, a large amount of unburned gas containing CO as a main component generated by blowing and melting carbonaceous materials, oxygen, etc. is burned to increase the thermal energy of the exhaust gas, and the high temperature exhaust gas is preheated. Since it is introduced into the furnace shell, the exhaust gas energy can be effectively used.In addition, the exhaust gas from the furnace shell on the preheating side is introduced into the melting furnace for supplying the initial molten metal and is thermally decomposed in the high temperature furnace to produce an odor. Even in the preheating of scraps that generate heat, all of the high-temperature exhaust gas from the furnace on the operating side can be used for preheating, and odorless high-temperature preheating can be performed regardless of the type of scrap.

〔Example〕

 Embodiments of the present invention will be described below with reference to the accompanying drawings.

The figure shows an example of the structure of the present invention. Reference numerals 1 and 1'represent a pair of furnace shells of a melting furnace, and a furnace shell 2 of a melting furnace for supplying an initial molten metal is provided between these furnace shells 1, 1 '. Has been installed,
Exhaust gas ducts 3, 3'connect the furnace shells 1, 1'of the pair of melting furnaces and the furnace shell 2 of the melting furnace for supplying the initial molten metal.

Dampers 4, 4 ′ are provided in the middle of the exhaust gas ducts 3, 3 ′, and front and rear parts of the dampers 4, 4 ′ are break flanges 5, 5 ′ for separating the furnace body from the fixed ducts, 6,6 ′
Connected by.

Further, another exhaust gas duct 7 is connected between the furnace shells 1 and 1 ′ of the pair of melting furnaces. This exhaust gas duct 7 is for each furnace shell 1,
1'is connected via break flanges 8 and 8 ', and in the middle of this exhaust gas duct 7, combustion for burning exhaust gas containing unburned gas generated in the furnace shell 1 or 1'of the melting furnace on the operating side The tube 9 is connected.

An exhaust gas duct 11 of a bypass line communicating with the dust collector 10 is connected to the furnace shell 2 of the melting furnace for supplying the initial molten metal.

In the figure, reference numerals 12 and 12 'are spouts, 13 are electrodes, 14 is a secondary side conductor, 15 is a power supply cable, 16 is a power supply (furnace transformer), and 17 is a molten metal supply gutter.

The facilities 13 to 16 for electric current melting include not only the melting furnace 2 for supplying the initial molten metal but also the pair of melting furnaces 1 and 1 '.
It is equipped so that it can also be used.

Next, the mode of operation will be described.

Now, when one of the pair of melting furnaces is used as a furnace on the operating side and the other furnace shell 1'is a furnace on the preheating side, carbonaceous materials, oxygen, etc. are contained in the molten metal in the operating furnace shell 1. Fuel of
The scrap charged in the furnace shell 1 is melted.

Further, in the furnace shell 2 of the melting furnace for supplying the initial molten metal, scrap is being melted by electric current.

In this case, keep the damper 4 closed,
Exhaust gas from the furnace shell 1 of the melting furnace on the operating side was introduced into the combustion tube 9 and generated in the furnace tube 1 on the operating side in the combustion tube 9.
The exhaust gas containing unburned gas such as CO gas is burned to increase the heat energy of the exhaust gas, and the high temperature gas is introduced into the preheating side of the furnace shell 1 ′ to increase the preheating effect of scrap and to include the odor after preheating. The flue gas is thermally decomposed in the furnace shell 2 of the melting furnace for supplying the initial molten metal to be odorless during the energization operation, and is discharged to the atmosphere through the dust collector 10.

When the melting of the scrap in the furnace shell 1 of the melting furnace on the operation side is completed, the break flange is opened in the same manner as in the conventional case, and the furnace shell 1 is opened.
Tilt and tap the water.

Immediately before the completion of the operation in the furnace shell 1 of the melting furnace, the initial molten metal for fuel injection was supplied from the spout 12 'into the furnace shell 1'through the gutter 17 as a preparation for starting the operation in the furnace shell 1'. Keep it. At the same time when the operation in the furnace shell 1 is completed, the furnace shell 1'becomes the furnace on the operation side, and the fuel such as carbonaceous material and oxygen is blown to start the melting work. At this time, by closing the damper 4 ', the exhaust gas from the furnace shell 1'is introduced into the combustion tube 9 through the exhaust gas duct 7 in the same manner as described above.
The unburned gas such as CO gas is burned, and the high-temperature gas with increased thermal energy is introduced into the furnace shell 1 on the preheating side to efficiently preheat the scrap.

The description of the above embodiment is for the case of normal power-saving operation, but, for example, at night when the electricity rate is low, for example, during the melting for the initial molten metal generation, the electric power is melted toward the furnace on the operating side. It is also possible to shorten the operating time by rotating the devices 13 to 15 of (1) and (in addition to driving equipment) not only fuel injection melting but also electric melting.

In the illustrated embodiment, the case of using a three-phase AC arc furnace is shown, but the present invention is not limited to this, and needless to say, a melting furnace such as a DC arc furnace or a combustion furnace may be used. Is.

〔effect〕

As described above, the present invention is a dual melting furnace having two pairs of furnace shells, one of which is on the operating side and the other of which is on the preheating side, for supplying the initial molten metal to each of the furnace shells. Using a furnace shell and a combustion cylinder interposed in an exhaust gas duct connecting the furnace shells, the unburned gas in the exhaust gas from the furnace shell on the operating side is burned in the combustion cylinder, and then the furnace on the preheating side. After introducing it into the shell and preheating the scrap in the preheating side furnace shell, the exhaust gas was introduced into the initial molten metal supply furnace shell to decompose the odorous components in the exhaust gas, so carbonaceous materials, oxygen, etc. A large amount of unburned gas containing CO as a main component is burned in the combustion cylinder to increase the thermal energy of the exhaust gas, and the high-temperature gas is introduced into the furnace on the preheating side. Effective utilization can be achieved with high efficiency. In addition, since the odor component generated from the scrap on the preheating side is introduced into the melting furnace for supplying the initial molten metal and pyrolyzed in the high temperature furnace, there is no discharge of odor and at the time of preheating the scrap that also generates odor All of the hot exhaust gas from the furnace can be used for preheating. These make it possible to effectively use a large amount of exhaust gas energy generated by injecting fuel such as carbonaceous materials and oxygen, and have an excellent effect that odorless high temperature preheating can be performed without being restricted by scrap quality. Is obtained.

[Brief description of drawings]

The drawing is a block diagram showing an embodiment of the present invention. 1,1 ′ …… Smelting furnace shell, 2 …… Smelting furnace shell for initial molten metal supply, 3,3 ′, 7 …… Exhaust gas duct, 4,4 ′ …… Damper,
9 ... Combustion cylinder, 10 ... Dust collector.

Front page continuation (72) Inventor Sadao Higuchi 2-2-1 Otemachi, Chiyoda-ku, Tokyo Ishi Kawashima Harima Heavy Industries Co., Ltd. (72) Inventor Fumio Sato 3-30-1 Chijodai, Chiba, Chiba Prefecture (72) Inventor Hiroyuki Uesugi 1-22-20, Amanuma, Suginami-ku, Tokyo (56) Reference JP-A-59-1982 (JP, A) JP-A-58-156185 (JP, A) JP-A 61- 55579 (JP, A)

Claims (1)

[Claims] Claim: What is claimed is: 1. A melting furnace shell having a pair of two units, one of which is on the operation side and the other of which is on the raw material preheating side, and an initial molten metal for injecting fuel in communication with each of the melting furnace shells. A double melting furnace having a furnace shell for supplying an initial molten metal to be supplied, which is disposed in an exhaust gas duct connecting the two furnace shells for melting and is disposed in an exhaust gas from the furnace shell for melting on the operating side. Using a combustion tube that burns unburned gas, the high-temperature combustion gas obtained by burning the unburned gas in the exhaust gas of the furnace shell for melting on the operating side in the combustion tube to the furnace shell on the preheating side in the exhaust gas duct. After introducing and preheating the raw material in the furnace shell for melting on the preheating side, the exhaust gas after this preheating is introduced into the initial molten metal supply furnace shell during melting of the initial molten metal to remove the odorous components in the exhaust gas. An exhaust gas heat recovery method for a double melting furnace, characterized in that it is thermally decomposed and exhausted.