JPS6040580Y2 - Nose heat transfer accelerator for multi-zone heating furnace - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a structure of a nose portion forming a boundary between zones of a multi-zone heating furnace, and particularly to a device for promoting heat transfer in the nose portion.

BACKGROUND ART Conventionally, various techniques for promoting heat transfer within a furnace have been proposed as an energy saving measure for a heating furnace.

This type of heat transfer promotion technology includes methods to improve the radiant heat transfer efficiency of the flame itself, such as oil fuel atomization control method, oil fuel gas atomization method, method of adding carbon particles to gas flame, and methods to directly transfer high temperature combustion gas. A method is known in which convective heat transfer is promoted by colliding the heated object at high speed, and furthermore, a method is known in which a high emissivity object is suspended in a furnace to promote gas radiant heat transfer.

By the way, as shown in Fig. 1, there are preheating zone ■, heating zone ■,
In a multi-zone heating furnace 1 in which a heating zone ■ and a soaking zone ■ are installed sequentially in the furnace length direction, the nose portions 2 and 3 forming the boundaries between the zones
There is a problem that it is not possible to promote the heat transfer properties in a reasonable manner.

This is because, in the above-mentioned heating zone (■) and soaking zone (■), high flame radiation is obtained in the central part of the zone where the flame flame is blown, but on the other hand, the nose parts 2 and 3 and their vicinity are in the shadow of the flame, and the gas The layer thickness is thin and H2O in the combustion gas,
This is due to the low emissivity of impure gases such as CO2.

In particular, in a continuous casting heating furnace dedicated to hot charging, in which the bloom obtained by continuous casting is charged while still at a high temperature and heated to the temperature required for hot rolling, in relation to the continuous casting speed, Bloom is charged in batches, and each batch is sent into the heating furnace, so for example, as shown in Figure 1, even in one batch, the bloom located in the center part A of the band and the bloom located in the nose part are There is a problem that the firing temperature is different between the bloom located in the part B including No.3.

Therefore, in the above-mentioned continuous casting heating furnace, baking is controlled so that the bloom baking temperature in section B is the required hot rolling temperature, but as a result, section A tends to be overheated. It is also unfavorable in terms of energy.

The present invention was developed to solve this problem, and it is possible to improve the heat transfer characteristics at the nose of a multi-zone heating furnace, thereby heating the object uniformly along the length of the furnace. It is an object of the present invention to provide a device for promoting heat transfer at the nose portion of a multi-zone heating furnace.

Therefore, in the present invention, a fixing device is installed on the furnace wall of the nose section, and a porous plate made of ceramic with an elevated porosity is tilted so as to face the object to be heated on the inside of the furnace at the nose section. A perforated plate that allows the combustion gas flowing inside the furnace from one band to the other to pass through the perforated plate, absorbs the thermal energy of the combustion gas, and has a higher emissivity than the combustion gas. The basic feature is that heat transfer in the nose is promoted by thermal radiation.

Hereinafter, the present invention will be described in more detail based on illustrated embodiments.

For example, as shown in FIG. 2 as an enlarged view of the nose section 3 between the heating zone ■ and the soaking zone ■ in FIG. The upper sides of two long and short heat-resistant Y studs 5 and 6 coated with a ceramic material are embedded, and a ceramic porous plate 7 with a high porosity is tilted at the lower ends of these Y studs 5 and 6 and supported inside the furnace.

As shown in the figure, the ceramic porous plate 7 is tilted at an angle θ with respect to the lower surface 3a of the nose portion 3 in the direction of the high-temperature combustion gas flow a heading from the soaking zone (1) to the heating zone (2). Surface 7 facing the object to be heated 8,..., 8
It is arranged so that high-temperature combustion gas flows in from side a.

The ceramic material used for the ceramic porous plate 7 is cordierite (2MgO・2A1□03・5Si
O2) Yamurai) (3A1203-2Si02) can be used, and the porosity is 7
It is preferable that it is 0% or more in order to reduce pressure loss.

Further, this ceramic porous plate 7 is provided over almost the entire length of the furnace width, so as to uniformly promote heat transfer in the furnace width direction of the nose portion 3.

With the above configuration, the high-temperature combustion gas flowing from the soaking zone (1) to the heating zone (2) is directed to the object to be heated 8. ..., 8 flows into the ceramic porous plate 7 from the opposing surface 7a side, and the high-temperature combustion gas that flows in flows out from the back surface 7b of the ceramic porous plate 7 through a large number of holes in the ceramic porous plate 7.

In this process, the sensible heat of the high-temperature combustion gas is absorbed by the ceramic porous plate 7, and the ceramic porous plate 7 becomes high temperature. Heated food 8.・
..., 8 is subjected to heat radiation.

In this case, the inclination angle θ of the ceramic porous plate 7 is such that the sensible heat of the high-temperature combustion gas is absorbed most effectively, and the inflow surface 7a of the high-temperature combustion gas is the object to be heated 8. ....

As opposed to 8, θ≦? Set appropriately within the range of r12.

In addition, in order to absorb the sensible heat of the high-temperature combustion gas, it is preferable to allow as much high-temperature combustion gas as possible to pass through the ceramic porous plate 7, and in this sense, the downtake section and the heated object 8. ..., 8, and close the space between the lower edge of the ceramic porous plate 7 and the heated object 8. ..., 8 is preferably made as small as possible.

A large 4-part heating furnace (furnace length: 45 m) as shown in Figure 1.
x furnace width IQm), the above ceramic porous plates 7, 7 were attached to each nose part 2, 3, and an experiment was conducted.
3 Lower heated object 8. ..., the temperature of 8 is about 15℃ on average
As a result, the uneven heat between the band center part A and the nose part B could be reduced accordingly.

As is clear from the above explanation, according to the present invention, it is possible to promote heat transfer in the nose part that forms the boundary between each zone of a multi-zone heating furnace, so that the heat transfer between the eccentric central part and the nose part can be promoted. It is possible to reduce the uneven heat that may occur between the objects to be heated as much as possible, and the heating efficiency of the nose part can be increased accordingly.
It is possible to improve fuel consumption per unit of production.

[Brief explanation of the drawing]

FIG. 1 is an explanatory view of a multi-zone heating furnace, and FIG. 2 is an explanatory enlarged cross-sectional view of the furnace nose showing an embodiment of the present invention. 1...Multi-zone heating furnace, 2, 3...Nose part, 4...Fireproof wall, 5, 6...Y stud, 7... ... Ceramic porous plate, 8. ...
, 8...Object to be heated.

Claims (1)

[Scope of utility model registration request] In the furnace wall structure of the nose section that forms the boundary between each zone of a multi-zone heating furnace, a fixing device is installed on the inside of the furnace of the fireproof wall of the nose section. A device for promoting heat transfer in a nose portion of a multi-zone heating furnace, characterized in that a perforated plate is fixed at an inclination of 90° or less so that the combustion gas inlet surface of the perforated plate faces an object to be heated.