JPS625533Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to the structure of a high-temperature burning wall that has been improved so that it can completely prevent backfire in high-temperature ranges and exhibit sufficient heat radiation as a luminous flame wall without causing any danger. be.

Burning wall is also known as luminous wall, and luminous wall furnace was first developed in America as a gas combustion method.
As shown in Figure 1 a and b, fuel gas G and combustion air A are mixed, the mixed gas is blown into the breathable refractory, and the mixture is combusted within the refractory, bringing the inner wall surface (bright flame surface) of the furnace to the highest temperature. The object to be heated in the furnace is heated by radiation heat transfer from the burning wall surface and convection heat transfer of the combustion gas.

In this case, the conventional burning wall surface is 1000
If kept at a high temperature above ℃, there is a fatal defect in that the wall heat conduction and the in-wall combustion zone move to the back side, causing backfire and damaging the equipment itself. Currently, the burning wall method is not adopted at all.

Therefore, the surface temperature of conventional burning walls is only about 800 to 1000°C, and they have not been used at all in high-temperature industrial furnaces with temperatures of 1200°C or higher.

The present invention was completed by solving these shortcomings, making full use of the features of the burning wall system, and improving the structure to make it suitable for high-temperature heating.
That is, as shown in Figs. 2 and 3, (1) From the air mixture chamber 2 to the pore nozzle (tube) 3
Since the bright flame gas is discharged through the pore nozzle 3, if the discharge speed of the pore nozzle is maintained (adjusted) above the combustion propagation velocity of the gas, even if the temperature from the discharge part exceeds the ignition temperature, the inside of the pore nozzle 3 will be Since the temperature is cooled by the gas mixture, there is no risk of backup fire.

(2) In order to prevent the temperature of the air mixture chamber 2 from rising due to heat transfer from the air-permeable refractory (porous brick) 1, the position (part) shown in Figure 2 is installed.
A heat insulating layer 5 is provided to further improve safety.

(3) Since the bottom of the breathable refractory 1, that is, the opposing refractory surface of the pore nozzle 3, is sealed 4, this seal corresponds to the so-called umbrella of the pore nozzle 3; ) to suppress the dynamic pressure of the discharged gas as shown by the arrow in Figure 3.
The gas flow is detoured to the side circumference of the small hole nozzle 3,
The gas flow within the breathable refractory 1 becomes uniform, and the radiant heat on the surface of the luminous flame wall becomes uniform.

Based on this effect, in the present invention, mixing and supplying gas and air can be applied to high-temperature firing, and a high-temperature and uniform burning wall can be achieved.

In the present invention, all gas fuels G can be used, and city gas, LPG, and gases generated in steel plants such as coke oven gas can be widely used.

Conventionally, the maximum heating temperature was 1000°C, but by adopting this invention, it has become possible to achieve practical heating temperatures of over 1200°C and even as high as 1350°C in test plant experiments.

In the present invention, the combustion propagation velocity of the mixed gas (G+A) to prevent backfire may be set to 1.85 m/sec or more in the case of city gas, for example.

In the present invention, the breathable refractory 1 may be either brick or monolithic refractory, and the material is generally clay, mullite, high alumina, etc., and other materials may be used depending on the applicable furnace. Can be used. So-called porous bricks are usually used, and although there are no particular limitations on their characteristic values, common and easily available bricks have an air permeability of about 30 to 100 c.c./cm ² and a sec. air permeability of about 100 to 1500/100 cm ² , min. (approx. 1-15/
cm ² , min.) is sufficient.

A space called an air mixture chamber 2 is provided inside the outer shell, into which gas G and air A are introduced through conduits by adjusting valves, and connected to the air mixture chamber 2, a small hole nozzle 3 is normally installed. A plurality of them (two to several in a breathable refractory block) are provided, but it goes without saying that there may also be one, depending on the design. The fine-hole nozzle 3 may have a circular, elliptical, square, or polygonal cross section, but is generally pipe-shaped and conveniently made of metal, and there is no need to limit the material. The sealing part 4 is a coating material with adhesive strength that does not separate from the air-permeable refractory 1, and may be made of any material as long as it can withstand use, but generally a mixture of a refractory fine powder mixture and a binder is used.

The portions of the fine-hole nozzle 3 other than the opening on the side of the air mixture chamber 2 are covered with a heat insulating layer 5, and this material may be a cork board, an asbestos board, a ceramic fiber sheet, or the like.

Further, the small space 6 is a pipe-shaped spare around a thin tube for suppressing the dynamic pressure of the gas discharged from the fine hole nozzle 3 and making the gas flow uniform.
The distance between the tip of the pore nozzle 3 and the seal portion 4 is approximately 5~
30mm, gap around side wall of pore nozzle 3 is approximately 0.5~5
mm, and is formed as a gas passage to assist the above-mentioned function.

Since the above structure has been improved, the burning wall of this invention does not have the risk of backfire.
High-temperature heating above ℃ is now possible, and the compact, prefabricated furnace body can be easily and quickly constructed in any suitable location, allowing for efficient bright flame wall heating, energy saving, and even a burning wall. This is a gas combustion heating method that can be widely used in the field of high-temperature industry, saving labor and materials by making blocks and prefabricating.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a conventional burning wall, in which a is a general type and b is a modified type. FIG. 2 is a schematic cross-sectional view showing an example of the burning wall of the present invention, and FIG. 3 is an enlarged view of section A in FIG. 2. The symbols in the diagram are as follows. DESCRIPTION OF SYMBOLS 1... Breathable refractory, 2... Air mixture chamber, 3... Pore nozzle (tube), 4... Sealing part, 5... Heat insulation layer, 6...
Small space.

Claims (1)

[Scope of utility model registration request] An air mixture chamber 2 for mixing fuel gas and air is provided on the back side of the wall, and connected to the air mixture chamber 2, a small hole nozzle 3 is protruded into the breathable refractory 1 provided in contact with the combustion surface corresponding to the inner surface of the wall. The opening of the fine-hole nozzle 3 other than the opening on the side of the air mixture chamber 2 is shielded with a heat insulating layer 5, and a small space 6 is provided around and at the tip of the fine-hole nozzle 3. A seal portion 4 is provided on the inner surface of the breathable refractory 1.
Burning wall for high temperature use.