JPH0611273A - Heating furnace - Google Patents

Abstract

PURPOSE:To attain a flame temperature suitable for heating the materials in a furnace and a uniform interior furnace temperature by a method wherein a radiation pipe is installed in the furnace with both ends open therein and the one end is located at a predetermined space from a burner for burning pure oxygen or oxygen rich air. CONSTITUTION:A burner 2 is provided for a heating furnace 1 for heating materials such as a slab, billet and bloom. This burner 2 has connected thereto a fuel gas supply pipe 3, an oxygen supply pipe 4 and an air supply pipe 5 and is adapted to perform burning operation with oxygen alone or oxygen rich air. A radiation pipe 6 is installed in the heating furnace with both ends open therein and the one end is located at a predetermined space from the burner 2. A blast of the combustion gas is delivered from the burner 2 through the radiation pipe 6 and through one end part 7 into the furnace. On the other hand, the combustion gas in the furnace is sucked in the radiation pipe 6 from the other end part 8 thereof and mixed therein with the gas from the burner 2 and the resulting mixture is then blasted from the end part 7 into the furnace. The radiation pipe may be provided in arbitrary length and position of its open ends.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating furnace and a soaking furnace (generally referred to as a heating furnace in the present invention) used for heating a material to be heated such as a slab, a billet, and a bloom to a predetermined target temperature.

[0002]

2. Description of the Prior Art There are two problems when performing pure oxygen or oxygen enriched combustion in a heating furnace. One is that the flame temperature is too high and there is a risk of melting the material to be heated. The other is that the amount of combustion gas discharged from the burner is smaller than that during normal air combustion (about 1/4 in pure oxygen combustion). The temperature distribution in the furnace is likely to be non-uniform.

As a technique for solving these problems, there is a furnace combustion gas circulation combustion technique. That is, the flame temperature is lowered by circulating the combustion gas, and the amount of gas discharged from the burner is further increased to make the temperature inside the furnace uniform. Specifically, JP-A-52-18233 is disclosed. However, this technique has drawbacks in that the peripheral wall serving as a circulation passage for the combustion gas is exposed to high temperatures, the life is short, and the device becomes too large.

[0004]

DISCLOSURE OF THE INVENTION The present invention, in a heating furnace for performing pure oxygen or oxygen-enriched combustion, makes the flame temperature suitable for heating a material to be heated by stably and compactly performing combustion gas circulation combustion in the furnace. It is intended to provide a heating furnace which can achieve a uniform temperature and a uniform temperature inside the furnace.

[0005]

The heating furnace according to the present invention is
Characteristically, a radiation tube made of heat-resistant steel or ceramic of a required length with an open end at a certain distance from a burner performing pure oxygen or oxygen-enriched combustion is arranged so that the open end is located in the furnace. And

[0006]

A burner for performing pure oxygen or oxygen-enriched combustion ejects combustion gas into the furnace at high speed to prevent flashback.
The combustion gas in the furnace is entrained from the space between the burner and the radiant tube by using the energy at the time of this ejection. Combustion gas circulation In order to carry out stable combustion, it is a problem to properly mix the combustion gas ejected from the burner and the circulating combustion gas. In the present invention, however, this mixing is carried out in the radiant tube. It is easily obtained without being affected by the internal gas flow and buoyancy.

It is also possible to install a swirl device inside the radiation tube to further accelerate the mixing. In addition, since the radiation surface is solid due to the combustion in the radiation tube, the radiation is stabilized and the temperature distribution in the furnace can be made uniform. In particular, when the amount of combustion is small, the combustion gas flows in the tube, so that the temperature change of the radiant tube is small and the uniformity can be greatly improved as compared with the conventional combustion method.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiment shown in FIG. A burner 2 is arranged in a heating furnace 1 for heating a material to be heated such as a slab, a billet, and a bloom. A fuel gas pipe 3, an oxygen pipe 4, and an air pipe 5 are connected to the burner 2 so that the burner 2 can burn only oxygen or oxygen-enriched air.

A radiation tube 6 having an open end is arranged at a constant distance from the burner 2. The radiation tube 6 is made of heat resistant steel or ceramic. The combustion gas ejected from the burner passes through the radiant tube 6 and ends 7
Is jetted into the furnace from. On the other hand, the combustion gas in the furnace is sucked from the other end 8 of the radiant tube, mixed with the gas ejected from the burner in the radiant tube, and ejected from the end 7 into the furnace. The length of the radiation tube is free, and the position of the open end is arbitrary.

FIG. 2 shows another example of the present invention and is a sectional view of a heating furnace. The radiation pipes 6 are arranged in both the upper and lower parts, and the material to be heated 12 supported by the support pipe 11 is heated from the vertical direction. The upper radiation tube 6 is supported by the suspension rod 9 from the ceiling, and the lower radiation tube 6 is supported.
Are supported by the support 10.

[0011]

By carrying out the present invention described above,
Pure oxygen or an oxidation-enriched combustion burner can be stably used in a heating furnace, a uniform temperature in the furnace can be achieved, and a material to be heated can be heated in a stable state.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1 Heating Furnace 2 Burner 3 Fuel Gas Pipe 4 Oxygen Pipe 5 Air Pipe 6 Radiation Pipe 7,8 Radiation Pipe End 9 Suspension Rod 10 Support

Claims (1)

[Claims] 1. A radiation tube having an open end, the open end of which is located in a furnace, and one open end of which is disposed at a constant distance from a burner for performing pure oxygen or oxygen-enriched combustion. And heating furnace.