JPH0868502A - Furnace temperature distribution combustion control method - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide a method for controlling combustion in a uniform temperature distribution in a furnace by freely producing a stable flame at low cost. [Arrangement] A parallel fuel jet unit 3 in which an air jet unit 2 is installed in a furnace body and jets fuel parallel to the central axis of the air jet unit 2.
In addition to the above, the tilted fuel jet portion 5 that jets fuel at an angle to the central axis of the air jet portion 2 is provided, and while the air jet portion 2 jets air, the parallel fuel jet portion 3 The fuel is jetted alternately from the inclined fuel jetting unit 5 and burned. In the furnace, the fuel injection direction is switched near or far from the air injection part 2 at the same time or every hour to form a flame, and the temperature distribution in the furnace is made uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace temperature distribution combustion control method.

[0002]

2. Description of the Related Art Normally, as shown in FIG. 1, in a heating furnace, the amount of combustion required for heating is calculated and a burner having that capacity is installed, but the furnace structure is simple and low cost. In order to suppress it, select the burner with the largest capacity,
Make an effort to reduce the number. In addition, for the same purpose, the combustion device is often concentrated on one side to save space.

[0003]

In the conventional apparatus described above, in the case of a batch type heating furnace in which the treatment material does not move, the temperature distribution in the horizontal direction (flame propelling direction) in the heating furnace often deteriorates. In particular, if this occurs during soaking, which is the final stage of heat treatment, it is fatal. In order to avoid this, in the conventional heating furnace, efforts have been made to keep the temperature distribution in the furnace within a narrow range for the purpose of homogeneous treatment of the treated material, and a typical method is the multi-burner method. . In this method, a large number of small-capacity burners are placed downward from the ceiling or on both sides of the furnace body, and the ignition / extinction of each small-capacity burner is controlled by calculating the signals from multiple temperature sensors in the furnace. It is a method. It is also suitable for high-temperature furnaces with high radiant heating factors, and temperature control is easy for both horizontal X and Y axes.
There are several control rules for each small-capacity burner (for example, ignition is performed only in the low temperature part. The order and time of ignition are determined based on the characteristics of the furnace), but in any case, the temperature distribution is improved. Therefore, a large number of burners are required, and not only the burner body but also the costs for piping, wiring, and the control device and parts associated therewith are enormous. In this way, in order to control the temperature distribution in the horizontal direction of the heating furnace well, it is sufficient to arrange a large number of burners around and control the zones separately, but it is not complicated.
It also costs. Further, when a heat exchanger is provided as a means for recovering waste heat and heat is to be recovered as preheated air, the burner circumference is particularly complicated and expensive, and it is extremely difficult to adopt the multi-burner system.

[0004]

[Means for Solving the Problems] In order to solve the above problems,
The present invention provides a furnace body with an air jetting unit, and the furnace body is provided with a parallel fuel jetting unit for jetting fuel in parallel with the central axis of the air jetting unit. On the other hand, a tilted fuel jetting section that jets fuel at an angle is installed in the furnace body, and while jetting air from the air jetting section, fuel is jetted alternately from the parallel fuel jetting section and the tilted fuel jetting section. The present invention provides a method for controlling temperature distribution combustion in a furnace, which is characterized by causing combustion.

The present invention also provides a furnace temperature distribution combustion control method characterized in that fuel is jetted simultaneously from the parallel fuel jetting portion and the inclined fuel jetting portion to burn the fuel.

Further, according to the present invention, an air jet portion is provided in the furnace body, and an angle variable fuel jet portion is provided in the furnace body. While jetting air from the air jet portion, from the angle variable fuel jet portion, A furnace temperature distribution combustion control is provided, in which fuel is ejected and burned at a free angle with respect to a central axis of the air ejection portion.

Further, the present invention provides a furnace temperature distribution combustion control method characterized in that a plurality of the variable angle fuel injection parts are installed in a furnace body and are burned while alternately controlling the injection angle of the fuel. To do.

Further, according to the present invention, an air jet portion is provided in the furnace body, and a plurality of linear fuel jet portions are arranged in a line with respect to the central axis of the air jet portion in the furnace body. A furnace temperature distribution combustion control method, characterized in that fuel is jetted at an angle from the plurality of line-shaped fuel jetting portions, and mixed combustion with air jetting from the air jetting portion is performed. is there.

The present invention also provides a furnace temperature distribution combustion control method characterized in that the line-shaped fuel jetting portion is selectively jetted to control combustion.

[0010]

[Operation] In the furnace, near or far from the air jet,
The flame is formed at the same time or by switching it every time to make the temperature distribution in the flame propelling direction uniform in the furnace.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, in FIG. 3, reference numeral 1 is a furnace body, and 2 is an air ejection portion installed in the furnace body 1. A parallel fuel jetting portion 3 for jetting fuel parallel to the central axis of the air jetting portion 2 is installed in the furnace body 1, and the fuel is jetted at an angle with respect to the central axis of the air jetting portion 2. When the inclined fuel jetting unit 4 is installed in the furnace body 1 and air is jetted from the air jetting unit 2 while alternately jetting fuel from the parallel fuel jetting unit 3 and the tilted fuel jetting unit 4 to burn (energy (The capacities of the above are matched) and the combustion state shown in FIG. 4 is formed. That is, the fuel ejected from the parallel fuel ejection portion 3 mixes with air at a distance from the air ejection portion 2 to form a flame A. The fuel ejected from the inclined fuel ejection portion 4 mixes with air in the vicinity of the air ejection portion 2 to form a flame B. The result of performing this combustion alternately is shown in FIG. From FIG. 3 and FIG. 4, the flame peak point is shown in FIG.
It can be seen that the temperature distribution is lower than that of the conventional furnace shown in FIG. 2, and the temperature distribution is more uniform with respect to the material to be treated. Moreover, the high temperature retention zone (ZN), which correlates with the generation of thermal NOx, is remarkably small.
It can be seen that the generation of x is also suppressed.

Further, even when the fuel is jetted from the parallel fuel jetting portion 3 and the inclined fuel jetting portion 4 at the same time and burned, the flames A and B partially overlap each other, but the same effect as described above can be obtained. .

Further, as shown in FIG. 5, a single angle-variable fuel injection part 5 is attached to the furnace body 1, and the angle-variable fuel injection part 5 is attached to the central axis of the air injection part 2. The fuel is jetted at a free angle and mixed and burned with the air jetted from the air jetting unit 2. In this case, the peak points can be set freely, but if the peak points are obtained at the positions Pa and Pb as shown in FIG. 4, the same combustion result as in FIGS. 3 and 4 can be obtained.

Further, as shown in FIG. 5, a plurality of variable angle fuel injection parts 5 can be installed in the furnace body 1, and the fuel injection angles can be controlled to burn the fuel. Again, you can select peak points over a wide range,
The results shown in FIGS. 3 and 4 can be obtained.

Further, as shown in FIG. 6, a plurality of fuel jetting portions 6 are arranged in a line with respect to the central axis of the air jetting portion 2, and the fuel is jetted simultaneously from the plurality of fuel jetting portions 6. While being mixed and burned with the air jetted from the air jetting unit 2.
As a result, as shown in FIG. 7, it can be understood that the temperature distribution and the like of the object 7 to be processed are remarkably improved as compared with the conventional examples of FIGS. 1 and 2.

In FIG. 6, when the fuel injection portion 6 is switched and burned, a combustion result as shown in FIG. 8 is obtained. Also in this case, it is understood that the temperature distribution is remarkably improved and the other combustion results are significantly improved with respect to the material 7 to be treated, as compared with the conventional examples of FIGS. 1 and 2. it can.

[0017]

As described above, the present invention has the following effects. It is suitable for heating furnaces with an ignition temperature higher than that of the fuel used so that a stable flame can be freely generated, but basically it can be used in all temperature ranges from high temperature to low temperature if the ignition source can be maintained. Since the number of air supply devices, which occupy most of the cost of the combustion device, is halved, there is a great saving in equipment cost including auxiliary equipment (advantageous to the conventional multi-burner system). There are many types of furnaces with burners arranged on one side, in terms of space and ease of handling the cost. Actually, there are many furnaces, but when improving the temperature distribution of this furnace, it is a major modification. The purpose is achieved without doing. In other words, for both the coaxial type and the multi type, it suffices to position the conventional burner simply as an air supply device and add only the small-diameter fuel nozzle. 1 shows that the generation of NOx is very low and the high temperature retention zone ZN of FIG. 6 is very small compared to the conventional example of FIG. 1 and FIG. 2 and that thermal NOx is hard to generate, but since the fuel nozzle is used in multiple stages, The peak itself is less likely to occur, and NOx can be further reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a conventional furnace.

FIG. 2 is a combustion characteristic diagram of a conventional furnace.

FIG. 3 is a cross-sectional explanatory view of a furnace using the present invention.

FIG. 4 is a combustion characteristic diagram of the furnace shown in FIG.

FIG. 5 is a cross-sectional explanatory view of another embodiment.

FIG. 6 is a cross-sectional explanatory view of another embodiment.

FIG. 7 is a combustion characteristic diagram of the embodiment shown in FIG.

FIG. 8 is a combustion characteristic diagram according to another method of the embodiment shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2 Air ejection part 3 Parallel fuel ejection part 4 Inclined fuel ejection part 5 Angle variable fuel ejection part 6 Fuel ejection part 7 Processed material

Claims (6)

[Claims] 1. A furnace body is provided with an air jetting portion, and the furnace body is provided with a parallel fuel jetting portion for jetting fuel in parallel with a central axis of the air jetting portion, and a central axis of the air jetting portion. On the other hand, a tilted fuel jetting part for jetting fuel at an angle is installed in the furnace body, and while jetting air from the air jetting part, fuel is alternately jetted from the parallel fuel jetting part and the tilted fuel jetting part. A furnace temperature distribution combustion control method, characterized in that the fuel is injected and burned. 2. The in-reactor temperature distribution combustion control method according to claim 1, wherein fuel is jetted simultaneously from the parallel fuel jetting portion and the inclined fuel jetting portion to burn the fuel. 3. An air jetting unit is provided in the furnace body, and a variable angle fuel jetting unit is provided in the furnace body. While jetting air from the air jetting unit, the air jetting unit is blown from the variable angle fuel jetting unit. A method for controlling combustion in a furnace temperature distribution, characterized in that fuel is ejected at a free angle with respect to the central axis of the furnace and burned. 4. The in-reactor temperature distribution combustion control method according to claim 3, wherein a plurality of angle-variable fuel injection parts are installed in the furnace body and the fuel is burned while controlling the injection angle of the fuel. 5. A furnace body is provided with an air jetting portion, and a plurality of fuel jetting portions are arranged in a line with respect to a central axis of the air jetting portion in the furnace body, and the plurality of inclined fuel jetting portions are provided. A temperature distribution combustion control method in a furnace, in which the fuel is jetted at an angle from the above, and mixed combustion with the air jetted from the air jet portion is performed. 6. The in-reactor temperature distribution combustion control method according to claim 6, wherein combustion control is performed by switching and ejecting a plurality of inclined fuel jetting portions.