JP3577150B2 - Gas burner for glass melting furnace - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a gas burner used in a large-capacity heat storage type glass melting furnace (tank kiln).
[0002]
[Prior art]
In general, many large glass melting furnaces use heavy oil as fuel, but in recent years, gas-fired furnaces with low equipment costs have been used. FIG. 1 shows a schematic structure of a gas-fired glass melting furnace, in which a lower melting tank 5 is heated by direct heat from a flame of a gas burner 9 provided through a furnace wall 6 and reflected heat from a ceiling. The gas burner 9 employs a premixing type in which fuel and air are separately supplied into a furnace, and a long flame having a high emissivity is formed by diffusion combustion.
[0003]
[Problems to be solved by the invention]
However, in a glass melting furnace, radiation is dominant in heat transfer because the inside of the furnace is extremely high at 1500 to 1600 ° C. On the other hand, a gas combustion type using LPG or methane gas fuel is compared with a heavy oil combustion type. Since the radiant intensity of the flame is low, and particularly the unburned portion at the base of the flame is relatively long, there is a problem that the temperature near the burner 9 is considerably lower than the temperature far away. FIG. 2 shows the temperature distribution in the furnace measured by temperature sensors T1, T2, and T3 provided at three places on the ceiling. In FIG. 2, the broken line indicates the temperature distribution when a conventional single-hole gas burner 9 is used. However, compared to the ideal temperature distribution shown by the solid line, it can be seen that the maximum radiating portion of the flame is biased toward the tip.
[0004]
FIG. 3 shows a structure of a branch type gas burner which has been attempted to improve this. The auxiliary gas nozzle 12 is branched from a main gas nozzle 11 and fitted into a plurality of burner insertion holes 10 formed in the furnace wall 6. By inserting and making the diameter of the auxiliary flame hole smaller than that of the main flame hole, an auxiliary flame having a shorter flame length than the main flame is ejected. According to this configuration, a distance is secured between the main gas nozzle 11 and the auxiliary gas nozzle 12 such that the flames do not mix with each other, so that the auxiliary flame burns independently without being affected by the main flame, and It is possible to configure so that the maximum emission part of the auxiliary flame comes to the side of the low temperature part at the base of the main flame, so that the temperature distribution in the furnace approaches the ideal pattern without shortening the length of the main flame Can be.
[0005]
However, in the configuration of FIG. 4, two auxiliary nozzle insertion holes 9 must be provided on both sides of the main nozzle insertion hole 8 in the furnace wall 3, which complicates the furnace construction work and increases the cost. However, there is a drawback that it is not possible to use the existing melting furnace by replacing only the burner. In view of the above, the present invention has a gas burner structure that can form an auxiliary flame independent of the main flame, does not require the auxiliary nozzle insertion hole 9, and can therefore be used as it is in an existing melting furnace. It is intended to provide.
[0006]
[Means for Solving the Problems]
As shown in FIG. 4, the gas burner for a glass melting furnace according to the present invention is provided with a plurality of auxiliary flame holes 3 having a flame hole axis inclined outward around a main flame hole 2 provided at the center of a nozzle tip 1. Thus, the diameter of the auxiliary flame hole is set to 1/4 to 1/10 of the main flame hole, the inclination angle of the auxiliary flame hole 3 is set to 15 to 30 degrees, and the length of the auxiliary flame hole 3 is set to 5 to 5 mm of the diameter. In the invention according to claim 2, the flame hole axis of the auxiliary flame hole 3 is further inclined by 15 to 45 degrees in the circumferential direction, as shown in FIG. .
[0007]
[Action]
According to the above configuration, since the distance that the main flame and the auxiliary flame do not mix with each other is ensured, the auxiliary flame burns independently without being affected by the main flame, and thereby, the base of the main flame is thereby reduced. It is possible to configure so that the maximum emission part of the auxiliary flame comes to the side of the low temperature part, and the temperature distribution in the furnace can be made closer to the ideal pattern without shortening the length of the main flame. Of course, the auxiliary flame can be burned independently by increasing the distance between the main flame hole 2 and the auxiliary flame hole 3 without providing the auxiliary flame hole 3 with an inclination angle. Due to the extremely high temperature of about 0 ° C., making the gas nozzle 4 thick has problems in that heat is dissipated from the nozzle insertion hole 5 and that the nozzle tip 1 is damaged, and only the nozzle tip protrudes from the furnace wall. It is not possible to make the metal gas nozzle thicker in view of the heat resistance of the metal gas nozzle.
[0008]
Also, as shown in FIG. 4B, if the flame hole axis of the auxiliary flame hole 2 is inclined in the circumferential direction, the same effect as that of the short flame can be obtained even with the auxiliary flame hole having a relatively large diameter. Therefore, heat radiation from the auxiliary flame can be further improved.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 shows an example of a glass melting furnace using the burner of the present invention. In a melting tank 5 provided at the lower part of a furnace 4 having a curved ceiling, raw materials are charged from one end and the other end. The left and right furnace walls 6 are provided with vent holes 8 communicating with the heat storage chambers 7 at a plurality of locations, and the furnace wall 6 immediately below each vent hole 8 is provided with a gas burner. 9 are penetrated. The left and right gas burners 9 are alternately supplied with fuel gas at regular intervals (15 to 30 minutes) to repeat combustion and stop, and from the combustion side (left side in the figure) vent 8 through the heat storage chamber 7 to 900 Combustion air preheated to １1100 ° C. is ejected, and fuel gas ejected from a gas nozzle comes into contact with the combustion air to diffuse and burn, thereby forming a long and red flame. The high-temperature exhaust gas is sucked into the ventilation port 8 on the stop side (the right side in the figure), passes through the heat storage chamber 7, heats the heat storage material, and is then discharged to the outside.
[0010]
FIG. 4 shows the structure of a nozzle tip attached to the tip of a gas burner used in the present invention. Around the main flame hole 2 provided at the center of the nozzle tip 1, a flame hole axis is directed outward by α. A plurality of (3 to 8) auxiliary flame holes 3 inclined at an angle of β degrees in the circumferential direction are provided, and the diameter D2 of the auxiliary flame hole is set to the diameter D1 of the main flame hole 2 (D1 in the case of 1,000,000 kcal / h, = 10 to 20 mm) and 1/4 to 1/10 (that is, D2 = 1 to 5 mm), the inclination angles α = 15 to 30 degrees, β = 15 to 45 degrees, and the length of the auxiliary flame hole 3 D3 is 5 to 15 times the diameter D2. The auxiliary flame hole 3 is made smaller than the main flame hole 2 in order to emit an auxiliary flame having a shorter flame length than the main flame and distribute the radiation intensity of the auxiliary flame to the front side of the center of the furnace. By appropriately selecting the number of auxiliary flame holes 2, a temperature distribution very close to the ideal temperature distribution can be realized as shown by the solid line in FIG. When the amount of combustion is increased by n times, the sectional area of the main flame hole 2 and the total sectional area of the auxiliary flame holes 3 may be increased by n times.
[0011]
The reason why the upper limit of the diameter ratio D2 / D1 of the auxiliary flame to the main flame is set to 1/4 is that if the auxiliary flame is made longer, the center of the radiation intensity of the auxiliary flame becomes too close to the center of the furnace, and This is because it deviates from the purpose of distributing the intensity evenly, and the lower limit is set to 1/10. If the auxiliary flame is shortened further, the radiation intensity from the auxiliary flame decreases, and the front side also This is because the effect of increasing the strength is lost. The reason why the ratio D3 / D2 of the length to the diameter of the auxiliary flame hole is made sufficiently large is that the auxiliary flame and the main flame are mixed by rectifying the gas flow in the auxiliary flame hole to have directionality. This is to prevent the flame from unifying and prevent the auxiliary flame from being cooled by the main flame and being hindered from burning in front, but if this ratio exceeds 15, the ventilation resistance becomes too large and the auxiliary flame becomes too large. When the ratio becomes 5 or less, the auxiliary flame does not form a laminar flow, so it diffuses at the exit of the flame hole 3 and mixes with the main flame. The angle of inclination α of the auxiliary flame to the outside is set to 15 to 30 degrees because the auxiliary flame approaches the main flame too much below this, and because it spreads too much around it, the flame temperature drops. The reason that the auxiliary flame is inclined in the circumferential direction is that the auxiliary flame is swirled around the main flame to shorten the flame without reducing the ejection speed as much as possible. After sufficient separation, the auxiliary flames approach each other as much as possible to prevent the combustion temperature from lowering and to maintain the radiation intensity, but the inclination angle β is set to 15 to 45 degrees even if it is less than this. This is because even with the above, effective turning is not performed.
[0012]
【The invention's effect】
According to the present invention, as described above, since the distance between the main flame and the auxiliary flame is such that the flames do not mix with each other, the auxiliary flame burns independently without being affected by the main flame, As a result, there is an advantage that the maximum radiating portion of the auxiliary flame comes to the side of the low temperature portion at the base of the main flame so that the temperature distribution in the furnace can be made closer to the ideal pattern. Unlike the conventional example, there is no need to provide a plurality of burner insertion holes 10 in the furnace wall 6, so that the furnace can be built easily and at low cost, and the existing furnace can be improved only by replacing the burner. There are advantages.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a glass melting furnace common to the present invention and a conventional example.
FIG. 2 is a furnace temperature distribution diagram showing an operation state of the present invention.
FIG. 3 is a sectional view of a conventional example.
4A is a sectional view of a main part of the present invention, and FIG. 4B is a top view of the same.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Nozzle tip 2 Main flame hole 3 Auxiliary flame hole 4 Furnace 5 Melting tank 6 Furnace wall 7 Heat storage room 8 Vent 9 Gas burner 10 Burner insertion hole 11 Main gas nozzle 12 Auxiliary gas nozzle

Claims (2)

A plurality of auxiliary flame holes are provided around the main flame hole provided at the center of the nozzle tip, the diameter of the auxiliary flame hole is set to 1/4 to 1/10 of the main flame hole, and the flame hole axis of the auxiliary flame hole is provided. A gas burner for a glass melting furnace, characterized in that the outer flame is inclined 15 to 30 degrees to the outside and the length of the auxiliary flame hole is 5 to 15 times the diameter. 2. The gas burner for a glass melting furnace according to claim 1, wherein the flame hole axis of the auxiliary flame hole is inclined by 15 to 45 degrees in the circumferential direction.

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