JPH11230543A - Operation method of heat storage regenerative-type burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for operating a heat storage regenerative-type burner which is capable of obtaining an excellent energy saving effect in a wide range from a low temperature region to a high temperature region, and ensuring a temperature distribution which has an excellent agitating effect in a furnace. SOLUTION: A plurality of heat storage regenerative-type burners 2a, 2b, 2c, 2d which are arranged in a furnace 1, are combusted while changing the ratio of a combustion time to a combustion period of a burner, and the combustion time of the burner, according to the furnace temperature. Specifically, in a low temperature region, the ratio of the combustion time to the combustion period of a burner, and the combustion time of the burner are decreased, while increasing the ratio of the combustion time to the combustion period of the burner, and the combustion time of the burner in a high temperature region so as to perform combustion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a regenerative burner disposed in various furnaces.

[0002]

2. Description of the Related Art A heat storage regeneration type burner is a burner having a heat storage body in a flow path of combustion air. As shown in FIG.
A set of books is installed in a furnace. As shown in FIG. 6, when the burner A burns, the exhaust operation is performed through the combustion air flow path of the burner B, and the heat of the exhaust gas is recovered by the heat storage body of the burner B. Next, when the burner B burns, the combustion air is preheated by the heat storage to increase the thermal efficiency of the burner, and the heat of the exhaust gas is recovered by the heat storage of the burner A on the opposite side. By repeating such a combustion operation and an exhaust operation, an excellent energy saving effect can be achieved as compared with a steady combustion system in which a normal burner is constantly burned.

However, the above-mentioned regenerative heat storage burner has the following two problems. First, since the regenerative burner has a high combustion temperature, the temperature inside the furnace is in a low temperature range (200 to 60).
0 ° C.), when the temperature rise speed is as slow as about 10 ° C./Hr, and when it is desired to secure a good temperature distribution, it is necessary to introduce excess air into the furnace to lower the combustion temperature, and the exhaust heat quantity is reduced. It increased and the energy saving effect was reduced. Further, if combustion is performed in a state where the burner output is reduced in order to secure a low temperature rise, the exhaust heat temperature of the furnace becomes low, so that the effect of the exhaust heat recovery by the heat exchanger could hardly be expected.

Secondly, as shown in FIG. 5, the regenerative regenerative burner is installed in a furnace as a set of two burners, so that the direction of gas flow in the furnace is fixed, so that the regenerative burner is simple. It becomes a reciprocating flow. Thus, there is a limit to the effect of stirring the flow in the furnace to make the temperature in the furnace uniform. In addition, the number of burners burning is always half of the number of burners installed in the furnace, so there was a limit to the heating speed. Accordingly, when the temperature in the furnace is high (600-1500 ° C.) and the rate of temperature rise is as fast as 300 ° C./Hr and a good temperature distribution is to be ensured, the burner capacity must be increased in advance when designing the furnace. Or the number of burners had to be increased, which required equipment costs.

Therefore, in a low temperature range, it has been studied to use an intermittent combustion system in which a normal burner is burned at a load of 100% and the temperature is controlled by turning on and off the burner for the heating furnace. However, this method is excellent in thermal efficiency because the amount of excess combustion air is suppressed in the low temperature range, but the amount of excess combustion air increases in the high temperature range, so there is little energy saving effect, and the entire system from low to high temperatures There is a problem that the thermal efficiency is low. In addition, it has been considered to install an intermittent combustion means and a regenerative combustion method in the heating furnace, switch to the intermittent combustion method in the low temperature range, and switch to the regenerative combustion method in the high temperature range. The second problem with burners was not solved at all.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and can obtain excellent energy saving effects in a wide range of furnace temperatures from a low temperature range to a high temperature range. The purpose of the present invention is to provide a method for operating a regenerative heat burner which is excellent in a stirring effect in a furnace and can secure a good temperature distribution.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a method for regenerating a plurality of regenerative burners disposed in a furnace by changing a combustion time with respect to a combustion cycle of the burner in accordance with a temperature in the furnace. And the combustion time of the burner is changed. In the low temperature range, the ratio of the combustion time to the burner combustion cycle and the burner combustion time are reduced, and in the high temperature range, the ratio of the combustion time to the burner combustion cycle and the burner combustion time are increased to perform combustion. I do. In the high temperature range, the number of burners burned simultaneously is reduced to 50% of the total number of burners.
It is preferable to set the number to exceed the number.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described in detail. FIG. 1 shows an embodiment of the present invention, wherein 1 is a furnace, 2a, 2b, 2c, and 2d are a plurality of heat storage regeneration burners attached to the furnace 1. Each burner 2a, 2b,
Each of the combustion air passages 2c and 2d is provided with a heat storage body 3 such as a ceramic honeycomb. The combustion air is preheated when passing through the heat storage body 3, and the combustion exhaust gas is exhausted when passing through the heat storage body 3. Heat is recovered. Each burner 2a, 2b, 2
In c and 2d, the burners to be burned are sequentially switched to repeat intermittent combustion while repeating supply and exhaust. The temperature control with respect to the set temperature is performed by changing the ratio of the combustion time to the combustion cycle of the burner (hereinafter referred to as the combustion time ratio) and the combustion time of the burner. Fine adjustment is made by changing the fuel output. be able to. The number of burners may be odd or even and intermittent combustion can be performed.

FIG. 2 shows an example of the intermittent combustion operation of the burner according to the present invention. In the figure, X indicates the burner combustion cycle,
Y indicates the burning time. The burning time ratio is expressed as Y / X. FIG. 3 shows an intermittent combustion operation of the burner in a low temperature range, in which the combustion time ratio is 15%, the combustion time is 5 seconds, and the combustion is performed intermittently. In this example, four burners sequentially burn at a combustion time ratio of 15%.
0% is burning either burner, but 40% is not burning any burners. Z is the fuel output of the burner, and fine adjustment of the temperature control with respect to the set temperature is performed by changing the fuel output Z. The firing order of the burners does not necessarily have to be fixed. For example, a burner having a low temperature in the furnace may be preferentially ignited. When the exhaust operation is performed immediately before the combustion, there is an advantage that the regenerator 3 is maintained at a high temperature and the effect of preheating the combustion air is great. However, the present invention is not necessarily limited to immediately before the combustion.

FIG. 3 shows an intermittent combustion operation of the burner in a high temperature range. Four burners 2a, 2b, 2c and 2d are arranged in the furnace, the burning time ratio is 70%, and the burning time is 4
Intermittent combustion is performed sequentially in 0 seconds. In this example, two or three of the four burners are burning, and one is performing an exhaust operation. As shown in FIG. 5, in the conventional heat storage combustion method, two burners are used as one set, so that the number of burners exceeding 50% cannot be burned. For this reason, in order to increase the heating rate to about 300 ° C./Hr and to secure a good temperature distribution, the burner capacity is increased in advance when the furnace is designed or the number of burners is increased. It was necessary and the equipment cost was high. On the other hand, in the present invention, the number of burners burning in the high temperature range exceeds 50% of the total number, and the above problem can be solved.

[0011]

Next, examples of the present invention will be described. FIG. 4 shows the relationship between the furnace temperature, the burning time ratio of each burner, and the burning time in this embodiment. The burner burning time ratio and burning time are changed according to the furnace temperature. 600
In a low temperature range of not more than ℃, the burning time ratio is reduced to 10 to 20%, and the burning time is reduced to 3 to 5 seconds. on the other hand,
In the high temperature range of 600 to 1500 ° C, the combustion time ratio is 2
Intermittent combustion is performed by increasing the combustion time to 5 to 70% and increasing the combustion time to 10 to 40 seconds. In this embodiment, the combustion time ratio and the combustion time are changed in steps, but may be changed by providing a gradient. Further, in this embodiment, the combustion time ratio and the combustion time are increased with respect to the increase in the furnace temperature, but may be decreased during the temperature rise.

Table 1 shows the temperature distribution in the furnace and the fuel consumption when the combustion time ratio and the combustion time are changed in this embodiment. Comparative Example 1 shows a conventional heat storage combustion method, and Comparative Example 2 shows a conventional steady combustion method. According to the invention, 20
In the low temperature range of 0 ° C. to 600 ° C., the fuel consumption can be reduced under the same temperature distribution conditions as Comparative Examples 1 and 2. In Comparative Examples 1 and 2, in order to ensure a good temperature distribution, it is necessary to introduce excess air in a low temperature range to lower the combustion temperature, and the amount of exhaust heat increases to lower the energy saving effect. In contrast, in the embodiment of the present invention, the combustion time ratio is reduced, the combustion time is shortened, and the combustion is performed intermittently, thereby suppressing the introduction of excess air. Further, since combustion can be performed with an optimum burner output under the above conditions, when performing low temperature rise in a low temperature range, there is no need to perform combustion in a state where the burner output is reduced (a state in which the exhaust heat temperature is low). The effect of exhaust heat recovery by the body is not reduced.

In a high temperature range of 800 to 1400 ° C.,
According to the present invention, the temperature distribution can be made smaller than in Comparative Example 1. This is because, in the conventional regenerative combustion system, since two burners are installed as one set in the furnace, the direction of the gas flow in the furnace is fixed, the reciprocating flow becomes simple, and the temperature in the furnace is made uniform. However, in the present invention, the combustion time ratio is increased, the combustion time is increased, and the combustion time is increased to perform intermittent combustion, thereby increasing the stirring effect of the furnace flow and increasing the furnace temperature. Can be made uniform. Further, under the above conditions, it is possible to burn with an optimum burner output, and even when performing rapid temperature rise in a high temperature range, there is no need to burn the burner output at a state close to 100%, so that the energy saving effect is not impaired. . Therefore, as shown in Table 1, the fuel consumption can be reduced as compared with the conventional heat storage combustion system (Comparative Example 1).

[0014]

[Table 1]

[0015]

As described above, according to the method of operating the regenerative regenerative burner of the present invention, an excellent energy saving effect can be obtained in the entire furnace temperature range from a low temperature range to a high temperature range. And a good stirring effect in the furnace, so that a good temperature distribution can be secured. Further, since there is no need to increase the burner capacity or the number of burners for obtaining a good temperature distribution, the equipment cost is reduced. Further, since there is no need to switch from the intermittent combustion system to the heat storage combustion system, it is not necessary to provide both means, so that the equipment cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a furnace showing an embodiment of the present invention.

FIG. 2 is a time chart showing the operation of each burner in a low temperature range.

FIG. 3 is a time chart showing the operation of each burner in a high temperature range.

FIG. 4 is a graph of a combustion time ratio and a combustion time corresponding to a furnace temperature in an example.

FIG. 5 is a plan view showing a conventional technique.

FIG. 6 is a time chart showing the operation of each burner in the prior art.

[Explanation of symbols]

 1 furnace, burner, 3 heat storage

Claims (3)

[Claims] The present invention is characterized in that a plurality of regenerative regenerative burners arranged in a furnace are burned while changing the ratio of the burning time to the burning cycle of the burner and the burning time of the burner according to the furnace temperature. How to operate a heat storage regeneration burner. 2. In a low temperature range, the ratio of the combustion time to the burner combustion cycle and the burner combustion time are decreased, and in a high temperature range, the ratio of the combustion time to the burner combustion cycle and the burner combustion time are increased to perform combustion. The method for operating a heat storage regeneration burner according to claim 1. 3. The method according to claim 1, wherein the number of burners to be burned simultaneously in the high temperature range is more than 50% of the total number of burners.