JPS58214781A - Preheater for scrap for steel manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention utilizes the large amount of heat contained in high-temperature exhaust gas discharged from steel-making melting furnaces (arc furnaces, etc.) to reduce steel-making scrap (
The present invention relates to an improvement of a preheating device for #steel scrap, which attempts to preheat steel scrap (hereinafter referred to as scrap).

In order to effectively utilize the heat of the high-temperature exhaust gas that is not generated in the melting furnace, the exhaust gas is passed through a heat exchanger, the recovered heat is used to heat the air, and the resulting hot air is transferred to the charging packet containing the scrap. A device that preheats the scrap by blowing air is disclosed in Jitsukaisho S!, which was previously filed by the present applicant. It is already known from the publication No. -di/j00.

However, in general, the scrap contains foreign substances such as plastic materials, and there is some dirt on the surface.

Because of the adhesion of oil and the like, when the scrap is preheated by the above-mentioned device, it burns or thermally decomposes, producing a foul odor and white smoke.

Therefore, if the gas is directly discharged into the atmosphere, there is a risk of causing air pollution 1 and deterioration of the working environment.

The present invention eliminates the risk of causing the above-mentioned pollution by circulating the gas flowing through the charging packet through a closed circuit consisting of a heat exchanger, a charging packet, and a circulation blower without discharging it into a large tank. The aim is to eliminate the

The following is a summary of the present invention along with the drawings. In Figure 1 for explaining an embodiment, 1 is a melting furnace, 2 is an exhaust pipe line for high-temperature exhaust gas generated in the melting furnace, 8 is an exhaust blower connected to the exhaust pipe line, and 4 is the exhaust blower. The dust collector 6 is an exhaust pipe, and the high-temperature exhaust gas generated in the melting furnace 1 is sucked by the exhaust blower 3 and flows through the exhaust pipe 2, and the dust collector 6 is installed on the outlet side of the dust collector. After being purified through 4, it is discharged into the atmosphere through the exhaust stack. Reference numeral 6 denotes a double cylindrical radiation heat exchanger having a heat radiation side flow path 7 on the inside and a heat absorption side flow path 8 on the outside, and the heat radiation side flow path 7 is connected to the exhaust pipe line 2. This allows the high temperature exhaust gas to pass through the heat radiation side flow path 7. 9 is attached to the outer periphery of the inner cylinder constituting the heat radiation side flow path 7! l! A fin provided in a spiral shape, 10 a hopper for discharging dust provided at the lower part of the heat radiation side flow path 7, 11
indicates a lid provided at the upper end so that it can be opened when cleaning the inside of the heat radiation side flow path 7.

On the other hand, this is a talam shell type charging packet with openings at the bottom and is configured so that scrap to be charged into the melting furnace 1 is charged from the top and taken out from the bottom. Reference numeral 13 denotes a platform for placing the charging packet, and a circular hole 14 is formed in the platform to fit the bottom of the bucket 12, and 18Il! is formed at the bottom of the circular hole. Qiyo 7
- a cord 15 is installed in series. Further, the upper part of the charging packet is covered with a blowing hood 16, thereby forming a through-flow path from the blowing 7-door 16 through the inside of the charging packet to the exhaust hood 15. Reference numeral 17 denotes a circulation blower, and the blowing side of the v# coral blower and one end 2 of the endothermic side flow path 8 of the heat exchanger 6 are connected by a pipe]8, and the end portion 2 of the endothermic side flow path 8 of the heat exchanger 6 is The other end and the blowing door 16 of the charging packet ν are communicated with each other through a pipe 19, and the exhaust hood 15 of the packetized unit and the suction side of the circulation blower 17 are connected with each other through a pipe connection. A closed circuit is formed, and a circulation blower 17 circulates the gas in the closed circuit in the direction indicated by the arrow in the figure. Reference numeral 21 denotes a flow rate control valve provided in the pipe 19 to adjust the flow rate of gas flowing through the closed circuit, and η is a burner provided in the pipe 19.

Also, at an appropriate location in the closed circuit (in the middle of the pipe in this embodiment) and ') 11. A communication pipe is provided that connects the inlet of the heat side flow path 7, an exhaust valve is provided in the communication pipe, and a communication pipe that connects the front part of the heat radiation side flow path 7 and the closed circuit pipe 19 is provided. 5 is provided, and a suction C valve base is provided in the communication pipe.

Since it is composed of the device number J or higher of the present invention,
The gas in the closed circuit is circulated by the action of the circulation blower 17, and when the gas is allowed to flow through the hot side flow path 8, it is heated and raised by the heat of the high temperature exhaust gas flowing through the heat radiation side flow path 7. , 1,000 hot gas is blown into the charging packetle from the blowing hood 16 through the pipe 19. Then, the scrap in the bucket) 12 is preheated by the hot gas. The gas whose temperature has been lowered by passing through the packet is sucked into the exhaust hood by the suction action of the circulation blower 17.

Then, air is again blown into the heat-absorbing flow path 8 of the heat exchanger 6 to reheat it, and thereafter the gas in the closed circuit is circulated until the scrap can be heated to a high temperature. At this time, if the scrap contains foreign substances such as plastic materials, or if paint, oil, etc. are attached to the surface of the scrap, they may be burned or thermally decomposed, producing foul odors, white smoke, etc. However, the gas is not discharged into the atmosphere and is circulated within a closed circuit, so there is no risk of pollution.

Further, when replacing the gas in the closed circuit, the exhaust valve 2A is opened to open the communication pipe, and the intake valve is opened to open the communication pipe. [01 Gas in the passage is allowed to flow into the exhaust pipe line 2 via the communication pipe n,
On the other hand, by causing the high-temperature exhaust gas in the exhaust pipe 2 to flow into the closed circuit via the communication pipe 5, the gas in the closed circuit can be smoothly exchanged. When the bad odor, white smoke, etc. generated during scrap preheating flow into the exhaust pipe 2, they are mixed with the high-temperature exhaust gas in the exhaust pipe 2, and some of them are burned and deodorized, and then the exhaust pipe 2 It is then released into the atmosphere.

Incidentally, combustible components accompanied by bad odor, white smoke, etc. generated during scrap preheating are burned when reheated to a high temperature in the heat-absorbing flow path 8, and furthermore, when they flow through the pipe 19, they are burned by the burner. By being burned by the flame of η, combustion heat is generated, and this heat is also used to preheat the scrap.

In addition, the scrap that has been preheated to a high temperature in the charging bucket) 12 is transferred to the top of the melting furnace 1 after stopping the flow of scrap in the closed circuit.
Since the bottom of the scrap 12 is opened and the scrap is charged into the melting furnace 1, the temperature of the scrap does not drop during that time and the scrap can be charged into the melting furnace in a short time, and a sufficient preheating effect can be obtained.

As described above with respect to the embodiments, the steelmaking scrap preheating device according to the present invention operates between the heat absorption side flow path of the heat exchanger interposed in the middle of the exhaust pipe for high-temperature exhaust gas generated in the melting furnace, and the inside of the charging packet. The through-flow path and circulation blower are connected to each other to form a closed circuit, and the scrap is preheated by circulating the gas in the closed circuit, so there is no odor or odor when preheating the scrap. Even if white smoke or the like is generated, the gas is circulated in a closed circuit, so it is not emitted into the atmosphere during preheating of scrap, which is beneficial in terms of pollution control.

[Brief explanation of the drawing]

The drawing is a system diagram of a steelmaking scrap preheating device showing an embodiment of the present invention. 1... Melting furnace! ... Exhaust pipe line, 6... Heat exchanger, 7... Heat radiation side flow path, 8... Heat absorption side flow path, 12... Charging packet, 17...・Circulation blower. n...Communication pipe, 24...Exhaust valve. Patent applicant: Daido Steel Co., Ltd.: ・：、、・

Claims (1)

[Scope of Claims] 1. A heat radiation side flow path of a heat exchanger is interposed in the middle of the exhaust pipe line for high-temperature exhaust gas generated in a melting furnace, and the heat exchanger installed opposite to the heat radiation side flow path absorbs heat. The side flow path, the through flow path of the charging packet into which steelmaking scrap is charged, and the circulation blower are communicated with each other to form a closed circuit, and the circulation blower circulates the gas in the closed circuit. A preheating device for steelmaking scrap, which is characterized by: 2. The device according to claim 1, characterized in that a communication pipe is provided to connect an appropriate part of the closed circuit to the heat radiation side flow passage inlet of the heat exchanger, and an exhaust valve is provided in the communication pipe. Preheating device for steelmaking scrap.