JPH0875109A - Control method of furnace temperature distribution combustion - Google Patents

Abstract

PURPOSE: To provide a uniform furnace temperature distribution combustion control method with use of low-cost stable flame. CONSTITUTION: A pair of regenerative air spray part 2 are mounted on a furnace body, and a fuel spray part 4 is mounted for spraying a fuel at an angle with respect to a center axis of each regenerative air spray part 2 whereby the fuel and preheated air are mixed and combusted. The regenerative air spray parts 2 are alternately switched and operated such that when one of them sprays air, stored heat is exhausted from the other thereof. Thereupon, the fuel spray part 4 selectively sprays the fuel from part or the whole or varying a spray angle in response to a furnace temperature region.

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, in a heating furnace, the amount of combustion required for heating is calculated and a burner with that capacity is installed, but in order to keep the furnace structure simple and low cost Select burners and make efforts 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 pair of regenerative air jets to a furnace body, and installs a fuel jet that jets fuel at an angle to the central axis of each of the regenerative air jets, Fuel is jetted from the fuel jetting section and air is jetted from the air jetting section for mixed combustion.
The regenerative air jetting portion is alternately operated so that heat is discharged from the other when one is jetting air, and the fuel jetting portion is operated depending on the temperature range in the furnace. It is intended to provide a method for controlling combustion in a furnace temperature distribution, which is characterized in that combustion is performed by selectively ejecting the fuel.

Further, the present invention provides a furnace temperature distribution combustion control method characterized in that fuel is jetted from all of the fuel jetting portions in a divided manner and simultaneously to be burned.

Further, the present invention provides a furnace temperature distribution combustion control method, characterized in that the fuel jetting portion is provided with a variable angle function to jet and burn the fuel in accordance with the furnace temperature range. It is a thing.

[0007]

[Function] The fuel is jetted according to the temperature range in the furnace, or the fuel is jetted from all of the fuel jetting parts and mixed and burned with preheated air to make the temperature distribution in the furnace uniform and improve the thermal efficiency. Suppress generation of nitrogen oxides.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference numeral 1 indicates a furnace body. Reference numeral 2 is a pair of regenerative air jetting units installed in the furnace body 1. Each of the paired regenerative air ejecting units has a built-in heat storage material, and when air is ejected from one side, it is exhausted from the other side and preheats the heat storage material 3 during the exhaust. The fuel jetting unit 4 is installed at an angle with respect to the central axis of each air jetting unit 2. The partially enlarged view in the figure shows a state in which the angle of the fuel injection unit 4 is variable by rotation.

Now, when the preheated air is ejected from one of the regenerative air ejecting portions 2 and the fuel is ejected from the fuel ejecting portion 4, the fuel and the air are mixed and burned. The fuel is jetted by selectively jetting fuel from a plurality of fuel jetting portions in the fuel jetting portion 4 according to the temperature range in the furnace, or jetting fuel in a divided manner from all the fuel jetting portions 4. Exhaust is performed from the other air jetting unit 2, but the heat storage material 3 is preheated at the time of exhaust. Air is jetted from the air jetting unit 2 alternately and alternately, for example, every several minutes to several tens of minutes.

At the time of the combustion, instead of jetting the fuel only from the fuel jetting portion 4 on the side of the regenerative air jetting portion 2 jetting air, the temperature range in the furnace is detected and the temperature condition is determined according to the temperature condition. The fuel injection section 4 on the Y side is selectively operated as appropriate. For example, not only the fuel injection portion 4 on the X side in the figure, but also the fuel injection portion 4 on the Y side is selectively ejected and burned according to the temperature inside the furnace. By this combustion, it is possible to ensure that the temperatures inside the furnace on the X side and the Y side are uniform. As a result of such combustion, almost the same combustion characteristics as shown in FIG. 4 can be obtained.

Further, for example, the fuel may be jetted in a divided manner at the same time from all the fuel jetting portions 4 and burned. The combustion characteristics in this case are as shown in FIG. The combustion characteristics of the present invention shown in FIG. 4 are compared with the combustion characteristics of the conventional apparatus using the regenerative burner shown in FIG. It can be clearly understood that both sides are made uniform and the generation of NOx is significantly reduced. In the above combustion, the total energy amount is calculated, so
The fuel is ejected within that range, but the amount of fuel ejected from each fuel ejection portion 4 can be changed according to the temperature inside the furnace.

The fuel injection part 4 may be of a fixed type having a fixed injection angle, but may be of a variable angle type as shown in the figure. In the case of a variable angle type, a desired position in the furnace is desired. It is possible to obtain a single flame or a plurality of flames at the same time or by switching them alternately. Then, depending on how the combustion mode is selected, excellent combustion characteristics as shown in FIG. 4 can be obtained.

[0013]

As described above, the present invention has the following effects. Usually, when using a so-called regenerative burner, it is often installed on one side of the device,
In this case, the temperature distribution in the flame propelling direction is poor, but in the case of the present invention, not only the flame propagating direction but also the temperature distribution in the entire furnace can be made uniform. 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. The generation of NOx is very low compared to conventional devices,
That is, it is proved that the high temperature zone ZN in FIG. 4 is much smaller than that in FIG. 1 and thermal NOx is hard to be generated.

[0014]

[Brief description of drawings]

FIG. 1 is a combustion characteristic diagram of a conventional device using a regenerative burner.

FIG. 2 is a cross-sectional explanatory view of the device of the present invention.

FIG. 3 is a cross-sectional explanatory view showing a reverse rotation mode of FIG.

FIG. 4 is a combustion characteristic diagram of the present invention.

[Explanation of symbols]

 1 Reactor body 2 Pair of regenerative air jetting part 3 Heat storage material 4 Fuel jetting part 5 Material to be treated

Claims (3)

[Claims] 1. A fuel ejection unit for ejecting fuel at an angle with respect to a central axis of each regenerative air ejection unit is provided. , The fuel is ejected from the fuel ejecting part, and the air is ejected from the air ejecting part to perform mixed combustion. As described above, the method is carried out by alternately switching, and at that time, the fuel injection part burns by selectively injecting in accordance with the in-reactor temperature range to perform combustion. 2. The fuel is jetted separately and simultaneously from all of the fuel jetting portion to burn the fuel.
A furnace temperature distribution combustion control method as described. 3. The in-reactor temperature according to claim 1, wherein the fuel injecting portion is provided with a variable angle function, and the fuel is injected from all or part of the incinerator according to the in-reactor temperature range and burned. Distributed combustion control method.