JPH0797618A - Method for controlling combustion in continuous reheating furnace - Google Patents

Abstract

PURPOSE:To unify the heating temp. in the width direction of a steel material by adjusting the position of the material to be heated in a furnace and the combustion quantity of a pair of burners in the case the width of the material to be heated is smaller in comparison with the furnace width. CONSTITUTION:In a continuous reheating furnace constituted so as to discharge the combustion exhaust gas to the outside of the furnace in each divided combustion zone after heating the material to be heated with one or more pairs of combustion burners arranged on both side walls of the furnace, in the case of heating the material having the smaller size compared with the furnace width, the material is arranged near one side of the furnace, and the combustion quantity of the combustion burner near the side of the material in the faced burners is made larger than that of the other side burner to execute the combustion. By this method, the heating temp. is uniformized in the width direction of the material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion control method for a continuous heating furnace capable of uniformly heating the material to be heated even when the size of the material to be heated is smaller than the width of the furnace. .

[0002]

2. Description of the Related Art When heating a steel material in a heating furnace, it is important to keep the temperature inside the furnace in each combustion zone at a constant temperature. In a heating furnace mainly composed of combustion from both side walls, there is no problem keeping the temperature inside the furnace constant when continuously heating a steel material having a length close to the furnace width, but it is extremely shorter than the furnace width. When heating a mixture of long steel materials, if a short steel material is loaded in the center of the furnace width direction, the combustion gas burned by the combustion burner installed on the side wall of the furnace does not reach the steel material and the thermal energy of the combustion gas is retained. There is a problem that the temperature inside the furnace rises because it is not sufficiently transmitted to the steel material.

Therefore, in a continuous heating furnace mainly composed of heating by one or more pairs of combustion burners which are made to burn from opposite side walls of the furnace, a steel material having a length shorter than the width of the furnace is heated. Occasionally, a heating method is adopted in which the steel material is brought close to one side wall of the furnace and heated only by the combustion burner provided on this side wall, and the combustion burner provided on the other side wall stops combustion.

[0004]

However, in a conventional continuous heating furnace in which both side walls of the furnace are opposed to each other for combustion, when the short material is heated close to one side of the furnace wall, the generated combustion exhaust gas is generated. Has a structure in which it is diffused into the atmosphere from the chimney at the bottom of the furnace through the pre-tropical zone, so that the combustion exhaust gas always flows in the furnace, and as shown in FIG. 3, the flame generated by the combustion burner 21 There was a problem that 22 was flowed to the downstream side of the furnace 23, and it was difficult to control the temperature of the steel material 24 in the furnace width direction.

The present invention has been made to solve the above-mentioned problems of the prior art, and when heating a short length of material to be heated in a continuous heating furnace, the material to be heated in the furnace width direction It is an object of the present invention to provide a combustion control method for a continuous heating furnace, which makes the temperature distribution of the furnace uniform.

[0006]

A combustion control method for a continuous heating furnace according to the present invention heats an object to be heated by one or more pairs of combustion burners provided on both side walls of the furnace, and separates combustion. In a continuous heating furnace configured to discharge combustion exhaust gas to the outside of the furnace for each zone, when heating a material to be heated that is smaller than the furnace width, bring the material to be heated to one side in the width direction of the heating furnace. Out of the opposing combustion burners,
It is characterized in that the combustion amount of the combustion burner closer to the material to be heated is made larger than that of the other burner for combustion.

[0007]

In the combustion control method for the continuous heating furnace according to the present invention, the combustion exhaust gas generated when the material to be heated is heated is discharged outside the furnace for each divided combustion zone. The flue gas in the combustion zone does not flow and the flame is not blown away. Therefore, when a short length of the material to be heated is biased to one side wall of the furnace and heated by a burner provided on the side wall, it is possible to heat the short length of material to have a uniform temperature distribution in the furnace width direction. it can. Moreover,
The combustion amount of the burners provided on both side walls is increased by increasing the combustion amount of the burner on the side to which the short length of the material to be heated is offset, and by decreasing the combustion amount of the other burner, the short length of the burner is reduced. The uniformity of the temperature distribution of the material to be heated in the furnace width direction can be further enhanced.

[0008]

EXAMPLE A combustion control method for a continuous heating furnace according to an example of the present invention will be described with reference to FIG. FIG. 1 shows that a short steel slab 1 is biased to a furnace wall 2a on one side of a continuous heating furnace 2 by burners 3a and 3b provided on the furnace wall and burners 3c and 3d provided on the other furnace wall 2b. It is a top view showing the situation of heating. The furnace width of the continuous heating furnace 2 is designed so that a steel piece having a length of 4500 mm can be charged, and the furnace 2 has a thickness of 200 mm, a width of 1000 mm, and a length of 2000 m.
When the short steel piece 1 having a length of m is heated to the furnace wall 2a by moving it toward the furnace wall 2a, the combustion amount of the burner 3a or 3b on the furnace wall 2a side is the combustion amount when the steel piece having a length of 4500 mm is heated. For V, (2000/4500) × V≈0.4
4 × V, that is, the maximum amount of combustion is 44%,
As a result of the trial, the combustion amount of the burner 3c or 3d provided on the other furnace wall 2b was 1/5 of the length of the part without the steel slab.
The amount of heating, {(4500-2000) / 450
0} × (1/5) × V≈0.11 × V, that is, the combustion amount was 11% of the maximum.

That is, as shown in FIG. 2, the flame 4a of the burner 3a on the furnace wall 2a side is made long and the flame 4c of the burner 3c on the furnace wall 2b side is made short. As a result, when burned by the conventional method, the steel wall 1 of the furnace wall 2
The temperature difference of 27 ° C. between the temperature on the a side and the temperature of the end of the steel slab 1 from the center of the furnace width could be kept within the temperature difference of 6 to 8 ° C. When the burner amount of the burner 3c or 3d on the side without the steel slab 1 is smaller than this, the temperature of the end portion of the steel slab 1 from the center of the furnace width decreases, and conversely when the combustion amount is larger than this. It was confirmed that the temperature of the end of the slab 1 from the center of the furnace width increased and the temperature distribution of the slab 1 in the furnace width direction was not uniform.

As described above, when the steel slab 1 is heated to the one side of the furnace wall by shifting it to one side, the ratio of the combustion amount of the burner on the one side to the combustion amount of the burner on the opposite side is appropriately changed. It is important to note that this ratio is affected by the thickness of the slab, the amount of heat treatment, the means of transporting the slab, etc. Need to decide.

When the regenerative burner is heated by alternating combustion, the burner 3a on the side of the furnace wall 2a burns a large amount and the flue gas is stored through the regenerator of the burner 3b on the same side of the furnace wall 2a. Alternatively, a method of burning a small amount in the burner 3d on the side of the furnace wall 2b and storing the combustion exhaust gas through the heat storage body of the burner 3c on the side of the same furnace wall 2b may be used, or the combustion exhaust gas may be stored in the heat of the furnace wall on the opposite side. The heat may be stored through the heat storage body of the type burner.

[0012]

According to the present invention, the temperature distribution of the steel material to be heated in the furnace width direction can be made uniform.

[Brief description of drawings]

FIG. 1 is a plan view showing a combustion control method for a continuous heating furnace according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram in the case of performing alternating combustion by the combustion control method of the continuous heating furnace according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a conventional combustion method.

[Explanation of symbols]

 1 Steel piece 2 Continuous heating furnace 2a Furnace wall 2b Furnace wall 3a, 3b, 3c, 3d Burner 4a, 4c Flame

Claims (1)

[Claims] 1. A continuous heating system configured to heat an object to be heated by one or more pairs of combustion burners provided on both side walls of the furnace and to discharge combustion exhaust gas to the outside of the furnace in each divided combustion zone. In a furnace, when heating a material to be heated that is smaller than the width of the furnace, the material to be heated is placed close to one side in the width direction of the heating furnace, and the one of the opposing combustion burners that is closer to the material to be heated is placed. A combustion control method for a continuous heating furnace, characterized in that combustion is performed with the combustion amount of the combustion burner being larger than that of the other burner.