JPS597884A - Recovery device for waste heat in metal melting furnace - 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 relates to a waste heat recovery device for a metal melting furnace, and more particularly to a device that can efficiently recover and effectively utilize the enormous amount of waste heat generated in a metal melting furnace.

Metal melting furnaces operate at high temperatures. For example, in the case of an arc furnace for steelmaking, the temperature reaches about 3000 degrees at a hot spot near three electrodes inserted into the furnace. Therefore, metal melting furnaces are constructed of high-grade refractory bricks;
Even such refractory bricks degenerate and, in some cases, melt away when exposed to high heat, so the furnace walls must be constantly repaired and reinforced.

Therefore, in recent years, a cooling chamber is formed in the furnace wall above the slag line of a metal melting furnace, and water is allowed to flow through the cooling chamber to cool the furnace wall, thereby increasing the lifespan of the refractory bricks used in the furnace wall. The long comb is ultimately intended to ensure the durability and safety of the metal melting furnace.

However, the conventional method of diagonal heating has a problem in that the waste heat of the metal melting furnace taken away during cooling of the furnace wall is not utilized at all, but is emitted completely wastefully.

For example, in the case of arc furnaces for steelmaking, they are extremely general-purpose;
Approximately 150 to 200 per hour per furnace wall in the water cooling room
X 10 Kcal of heat is completely wasted. The reason for this is that the direct purpose of the conventional method of tilting is to cool the furnace wall, but more importantly,
Water is used because it is sufficient to achieve this cooling purpose, but when water is passed through the cooling chamber, some of it is vaporized by the high heat of the reactor walls that are being cooled. It is extremely unstable and difficult to effectively utilize the sensible heat of a mixture of hot water and steam discharged from a chamber.

The present invention is based on the natural premise of cooling the furnace wall of a metal melting furnace,
The purpose of the present invention is to provide a device that efficiently recovers and effectively utilizes the enormous amount of waste heat taken away during cooling.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention will be explained in detail based on drawings, taking an arc furnace for steel manufacturing as an example.

FIG. 1 is a system diagram showing one embodiment of the present invention.

Water cooling portions 4.5.6.7.8.9 are formed at six locations on the furnace wall 3 of an arc furnace 2 into which three electrodes 1 are inserted. The water cooling parts illustrated in the drawings are mutually independent water cooling chambers or water cooling boxes, but there are also water cooling pipes, water cooling pans, etc., in which the water cooling parts are interconnected. These methods may be selected as appropriate.

The water cooling section formed on the furnace wall 3 and the heat exchange means 10 installed outside the furnace are connected by piping to constitute a circulation system 11. In the drawing, only the water cooling section 4 is connected by piping, and the other water cooling sections 5, 6, 7, 8, 9 are omitted, but these are also connected by piping separately as in the case of the water cooling section 4. It is. However, this piping connection form itself is not limited, as it differs depending on whether, for example, the water cooling parts are mutually independent or mutually connected, as described above.

The circulation system 11 is mostly fixed piping, but the arc furnace 2
The portion adjacent to is the movable pipe 12, 13. This is because the arc furnace 2 is tilted during tapping, for example, and it is necessary to follow the tilting operation.

The circulation system 11 still includes a circulation pump 14, a control valve 15,
An on-off valve 16, a check valve 17, and a differential pressure gauge 18 are interposed, and in the case of the drawing, a cooling system 19 and a buffer system 20 are also included. The cooling system 19 prevents the heat medium from reaching an abnormally high temperature as described later, and includes a cooler 21 and an on-off valve 22.
and a check valve 23, the buffer system 20 uniformizes the temperature of the heat medium as much as possible to be described later, supplies a stable amount of heat to the heat exchange means 10, and also serves as a safety function for the entire device. It is equipped with an intermediate tank 25 with an open top and a thermometer 24 attached thereto, and a liquid sending pump 26. Cooling section 4
These elements and systems interposed or incorporated in the circulation system 11 configured between the cooling system 19 and the heat exchange means 10 are the same as the cooling system 19 and the buffer system 20 described above, but for example, the cooling system 19 The on-off valve 16 is for switching the circulation path, the check valve 17 is for preventing the inconvenient backflow of the heat medium, and the differential pressure gauge 18 is for switching the heat from the circulation system. The purpose is to detect leakage of the medium, and these are appropriately disposed as necessary, and the example shown in the drawing is a preferred example.

The heat medium A is circulated through such a circulation system 11, and the cooling unit 4.
While cooling the furnace wall 3 of the arc furnace 2 in 5.6.7.8.9, the huge amount of waste heat removed during this cooling is effectively utilized in the heat exchange means 10. The heat transfer medium used in the present invention is an oil whose main component is a paraffinic hydrocarbon compound or an aromatic hydrocarbon compound, and typically is dowsome oil whose main component is a diphenyl compound. Dowsome oil has a maximum operating temperature of about 350°C, so if it is used as a heat medium, it can stably use a heat medium of about 300°C under controlled conditions.
0 can be supplied. Therefore, heat exchange means 1
If the heat medium is exchanged with water at 0, the water is easily vaporized, so the entire device can be used as if it were a boiler, and the heat exchange means 10 exchanges heat with the air. Then, since the air is easily heated, the entire device can be used like a drying device.

As explained above, the present invention has the effect of efficiently recovering and effectively utilizing the enormous amount of waste heat generated in a metal melting furnace.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing one embodiment of the present invention. 1. Electrode, 2- Arc furnace, 3. Furnace wall, 4.5, 9. Cooling section, 1o. Medium heat exchange means, 11. Circulation system, 14. Circulation pump, 15... Control valve, 19... Cooling system, 20
...Buffer system, A...Heating medium, patent applicant
Daido Steel Co., Ltd. Representative Patent Attorney Hiroshi Iriyama

Claims (1)

[Claims] 1. A circulation system is established by connecting the cooling part formed on the furnace wall of a metal melting furnace and the heat exchange means installed outside the furnace with piping, with a circulation pump or control valve appropriately interposed between the two. A waste heat recovery device for a metal melting furnace, comprising: a heating medium being circulated through the circulation system, and waste heat of the metal melting furnace is recovered by the heat exchange means.