JP2742236B2 - Heating method of material by open flame burner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a material using an open flame burner.

[0002]

2. Description of the Related Art When heating a material by an open flame burner, it is not necessary to locally heat the furnace or the material, but to heat the material by uniformly increasing the temperature in the furnace. It is important for improvement and energy saving. Therefore, in order to stir the atmosphere in the furnace as much as possible, a burner having a stirring function (high-speed burner) is employed.

However, even if this burner is used,
It is effective if the furnace width is within the range of the combustion flame.However, if the furnace width is wider than that, the stirring effect is bad for the turbulent stirring of the atmosphere flow in the furnace, and the effective stirring and mixing is effective. Can not fulfill. There is also a method of once extracting the gas in the furnace to the outside, forcibly circulating the gas in the furnace with a blowing device such as a fan or a blower, thereby increasing the amount of circulation of the furnace atmosphere and making the furnace temperature uniform. However, no matter how the heat recovery is performed, there is a problem that the thermal efficiency is inevitably reduced, and the structure becomes complicated and the equipment cost increases.

Accordingly, an object of the present invention is to provide a method of heating a material by a direct fire burner which can make the furnace temperature uniform and increase the thermal efficiency only by adding a simple structure.

[0005]

According to the present invention, in order to achieve the above-mentioned object, a direct fire burner is provided when heating the material in the furnace from both sides by a direct fire burner arranged with the material in the furnace sandwiched therebetween. In each of the furnace spaces, a partition wall having both ends separated from the furnace inner wall is provided to divide each of the furnace spaces into two in the same direction. The combustion directions are opposed to each other, and a combustion gas circulation flow in the same direction is formed around each of the partition walls.

[0006]

Next, an embodiment of the present invention will be described with reference to the drawings. In the figure, reference numeral 1 denotes a heating furnace main body composed of a furnace shell and a heat insulating wall. In the heating furnace main body 1, a plurality of heating zones A are formed by a plurality of zone partition walls 3 having a material passage opening 4 in the center. I have. In addition, the upper partition wall 5 and the lower partition wall 6 made of a heat insulating material do not contact the material W conveyed in the furnace on the ceiling 2a and the hearth 2b at the center of each heating zone A as described below. In addition, it is provided in parallel with the zone partition wall 3 and at a predetermined distance from the inner surfaces of the furnace side walls 2c, 2c, that is, via the communication passage 7. In addition,
The length of the upper and lower partition walls 5, 6 is preferably shorter than the width of the material W passing therethrough.

Reference numerals 8a to 8d and 9a to 9d denote direct-fire burners provided on the opposed furnace side walls 2c, 2c of the furnace main body 1. The upper and lower partition walls 5, 6 are used to set a heating zone A to a material W. The upper and lower partition walls 5 and 6 are provided in two upper and lower spaces B ₁ and B ₂ and B ₃ and B ₄ formed between the upper and lower spaces in parallel. And, the open flame burners 8a and 8b, 8c and 8d, 9a and 9b,
9c and 9d form a set, respectively. In addition, the direct fire burners 8a to 8d and 9a to 9d in the figures are known heat storage burners (Japanese Patent Laid-Open No. 6-11121) shown in FIGS. Here, since the direct fire burners 8a to 8d and 9a to 9d are all the same, the direct fire burners 8a and 8b forming a pair will be described.

[0008] As shown in FIG.
The burner main body 100 includes a fuel injection nozzle 101, an air flow passage 103 communicating with a burner throat portion 102, and a permeable heat storage body 104 arranged in the air flow passage 103. As shown in FIG. 5, the burners are attached to the furnace side wall 2c as a set of two units (8a, 8b). The fuel injection nozzles 101 of each burner 8a, 8b are connected to a gas supply source 107 via gas supply lines 106a, 106b having switching valves F1, F2, respectively. Further, the burner 8a, air supply line 108a with each air passage 103, 103 switching valve A1, A2 of 8b, while being connected to the air blower 109 through 108b, respectively changeover valve V _1,
Exhaust gas line 110a having a V _2, is connected to the induction fan 111 via 110b.

The set of burners 8a and 8b connected to the line as described above is provided for combustion of fuel gas and exhaust gas exhaust at predetermined time intervals, and is used by one burner for the other burner during gas combustion. It is operated while exhausting exhaust gas. That is, as shown, if the burning of gas at the burner 8a, this burner 8a is switching valve V ₁ with the switching valve F1, A1 is opened is closed, the gas supply source 107
The fuel gas is supplied from the nozzle 101 to the air blower 1.
From 09, combustion air is supplied to the air passage 103, and the fuel gas and the combustion air are injected into the furnace from the burner throat section 102 and burned. For the other burner 8b, the switching valve V ₂ opens with switching valve F2, A2 is closed, the exhaust gas in the furnace based on the driving of the induction fan 111 is discharged from the chimney 112 through the air passage 103,
At this time, the heat storage element 104 is heated by contact with the high temperature exhaust gas passing through the heat storage element 104.

Conversely, when burning gas with the burner 8b,
This burner 8b is switching valve F2, A2 is the switching valve V ₂ together are opened is closed, fuel gas is supplied to the nozzle 101 from the gas supply source 107, the air for combustion into the air passage 103 from the air blower 109 The fuel gas and the combustion air are supplied from the burner throat section 102 to the inside of the furnace 1.
13 and is burned. At this time, in the burner 8b, when the gas is burned by the burner 8a, the heat storage body 104 is used.
Since the heat is accumulated in the combustion air supplied from the air blower 109 to the air passage 103, the combustion air is preheated by contact with the heat storage body 104, and the fuel gas is burned together with the preheated combustion air. Therefore, the combustion efficiency of the fuel is remarkably improved as compared with the case where the fuel gas is burned together with the normal temperature air. On the other hand, for the burner 8a, the switching valve F
1, A1 is the changeover valve V ₁ is opened with the closed, exhaust gas in the furnace 113 is exhausted through the air passage 103, burner 8a heat of the hot exhaust gas is recovered in the regenerator 104
Is used for preheating combustion air at the next fuel combustion.

Next, a method of heating the material will be described. First, the material W made of a metal strip is conveyed in the furnace through the material passage opening 4 of the zone partition wall 3, and the direct fire burners 8a, 8d, 9a, and 9d are burned as described above. Air is exhausted from 8b, 8c, 9b, 9c and the heat storage body 104 is heated. Here, the space B ₁ ,
Describing the B _2, direct flame burners 8a, combustion gases from 8d is straight each space B _1, B ₂ and parallel and opposite upper partition walls 5, other direct flame burners 8b, 8c exhaust action of and open flame burners 8a, by the negative pressure generated in the base of 8d, the combustion gas containing flame from direct flame burners 8a enters the space B ₂ together with other furnace atmosphere through the communicating passage 7 by its own kinetic energy , Goes straight along with the combustion gas of the burner 8d. On the other hand, since the combustion gas of the direct fire burner 8d moves in the same manner as described above, the combustion gas of the two direct fire burners 8a and 8d entrains and mixes the atmosphere in the furnace while centering on the upper partition wall 5, as shown in FIG. To form a circulation flow a. If the partition wall 5 (6) does not exist, both combustion gases interfere with each other, and the combustion gas makes a U-turn in the direction of the direct fire burners 8b and 8c due to the exhaust action of the direct fire burners 8b and 8c (short path). No circulating flow is formed.

In the spaces B ₃ and B ₄ , a circulating flow b (not shown) having the same direction as that of the circulating flow a is also provided.
Is formed, and both surfaces of the material W are heated. Since the two circulation flows a and b have the same flow direction, the two circulation flows a and b do not collide with each other and generate turbulence. As described above, when the predetermined time has elapsed and the heat storage body 104 of the direct fire burners 8b, 8c, 9b, 9c performing the exhaust operation has reached the predetermined temperature, the direct fire burners 8a, 8d, 9a, 9d are extinguished. As a result, the material W is heated by burning the direct fire burners 8b, 8c, 9b, 9c.

Thus, on both sides (front and back) of the material W,
Direct flame burners 8a, 8d and 9a, each of the combustion gas and the space B of 9d _1, B ₂ and B _3, since the atmosphere B ₄ is circulating flow is mixed, with uniform heating of both surfaces of the material W Also, since the atmosphere in each space is uniformly heated, the heat transfer efficiency is also good.

In the above-described embodiment, an example in which a regenerative burner is used as the direct fire burner has been described. However, a general direct fire burner or a pure oxygen burner may be used as the direct fire burner so that the combustion gas is circulated as described above. The operation may be switched as appropriate so that half is burned and the other is extinguished. In addition, the direct fire burner is set only at the position of 8a, 8d, 9a, 9d or 8
b, 8c, 9b, 9c may be arranged only at the positions,
If the direct fire burners are operated alternately, the continuous operation time of the direct fire burner can be shortened and the life of the burner can be extended. In the above-described embodiment, the case where the conveying path of the material W is continuously heated in the horizontal state has been described. However, it is obvious that the conveying path may be in the vertical state or may be performed by batch heating.

[0015]

As is apparent from the above description, according to the present invention, when the furnace material is heated from both sides by the direct fire burner disposed with the furnace material interposed, the direct fire burner is provided. A partition wall having both ends separated from the furnace inner wall is provided in each furnace space, and the furnace space is divided into two in the same direction, and combustion of an open fire burner is performed in one divided area and the other divided area of each furnace space. The material is heated by an open flame burner in such a manner that the circulating flow is formed in the same direction around each of the partition walls with the directions facing each other.
Thus, the material is uniformly heated by the circulating flow in which the atmosphere is entrained in the combustion gas stream from both sides and mixed. In addition, since the atmosphere is sequentially entrained in the combustion gas stream and becomes uniformly high in temperature, the heat transfer efficiency can be improved by raising the furnace temperature.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional plan view of a heating furnace for carrying out the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a longitudinal sectional view of a heat storage burner.

FIG. 5 is a piping diagram of the heat storage burner of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Heating furnace main body, 2a ... Ceiling, 2b ... Furnace floor, 2c ... Furnace side wall, 3 ... Zone partition wall, 4 ... Material passage opening, 5 ... Upper partition wall, 6 ... Lower partition wall, 7 ... Communication passage, 8a ~ 8d, 9a
~9d ... direct flame burner, A ... heating zone, B _1, B _2,
B ₃ , B ₄ ... space.

Claims (1)

(57) [Claims] 1. A partition wall having both ends separated from a furnace inner wall in each furnace space in which a direct fire burner is disposed when the furnace material is heated from both sides by a direct fire burner disposed with the furnace material interposed therebetween. The furnace space is divided into two in the same direction in the same direction, the combustion direction of the open flame burner is opposed in one divided area and the other divided area of each furnace space, the same direction around each partition wall A method for heating a material by an open flame burner, wherein a combustion gas circulation flow is formed.