JPH0125868Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Industrial Application Field) The present invention relates to a radiant burner that transfers combustion heat of fuel to an air-permeable solid and heats an object using the air-permeable solid as a radiant heat source. (Prior art and its problems) In recent years, heated refractories with high thermal efficiency, mainly porous refractories, have been used as heating elements in place of general combustion burners, which are direct heating means, as heating devices in heating furnaces. Radiant burners are beginning to be adopted. By the way, as such a radiant burner,
Conventionally, there has been a type of burner in which a premixture of fuel and air is supplied into a porous solid and burned inside to generate heat in the porous solid. If the flow rate of the premixture becomes slow, there is a risk of flashback occurring. Therefore, as a countermeasure to this problem, a method was proposed in which a heat pipe was placed on the rear side of the porous solid to remove heat to the outside (Japanese Patent Application Laid-Open No.
10686) or a method of supplying a premixture with the primary air amount below the theoretical air amount and supplying secondary air separately to the combustion region (Japanese Patent Application Laid-open No. 56-56514). Although it is possible to manufacture a burner, there is a problem that the structure becomes complicated. Therefore, in recent years, as shown in Fig. 1, air and fuel are separately supplied to a combustion chamber 3 from an air supply pipe 1 and a fuel supply pipe 2, and are mixed and combusted inside the combustion chamber 3. A radiation type burner is used that generates heat in the air permeable solid 4. However, even in this radiation type burner, the heat load in the combustion chamber 3 is high and the collision of the air mixture flow against the air permeable solid 4 is strong, resulting in local heating. As a result, there is a problem that large thermal stress is generated in the body refractory 5 and the breathable solid 4, inducing cracks, melting damage, etc. In order to prevent as much as possible the occurrence of thermal stress caused by the temperature difference between the body refractories 5 and 5, refractories with good thermal conductivity are used. There were problems such as: (Purpose of the invention) The present invention was made in view of the above problems, and it supplies fuel and air perpendicularly to each other and makes the combustion chamber wide, thereby reducing the heat load and allowing local heating. It also prevents cracking and erosion of the body refractories and breathable solids due to thermal stress, and recovers the heat radiated from the body refractories with combustion air, improving combustion efficiency by preheating the air. The purpose of this invention is to provide a radiant burner with extremely high thermal efficiency that can improve the durability of the refractory itself. (Structure of the invention) In other words, the radiation burner of the invention includes a large-diameter cylindrical combustion chamber connected to the tip side of a fuel gas supply pipe, and an internal shell in which a permeable solid is disposed in front of the combustion chamber. , a cylindrical housing disposed around the outer circumference of the inner shell at a constant interval and having a combustion air supply pipe provided at its base end; and a cylindrical housing interposed between the inner shell and the cylindrical housing. a cylindrical member capable of forming a combustion air flow passage; and a plurality of combustion perforations radially formed in the inner shell for supplying combustion air in the passage to the combustion chamber in a direction perpendicular to the fuel gas flow. This radiation type burner will be described in detail below based on an embodiment shown in FIGS. 2 and subsequent figures. (Example) In the drawings, reference numeral 11 denotes an internal shell formed using an alumina cement-based refractory as a filler 12, and the internal shell 11 has a fuel gas supply pipe 13 connected to its base end side, and a fuel gas supply pipe 13 connected to the base end thereof. Supply pipe 13
A large-diameter cylindrical combustion chamber 14 is provided at the leading end of the combustion chamber 14, and an air permeable ceramic solid 15 is fitted and fixed in front of the combustion chamber 14. The air permeable solid 15 is fitted to the refractory material of the internal shell 11 by interposing and fixing a refractory heat insulating material 16 having elasticity such as ceramic fiber between the two. The difference in coefficient of thermal expansion between the two is absorbed by the fireproof insulating material 16, and cracks and damage between the two due to the difference in coefficient of thermal expansion can be prevented as much as possible. The air-permeable solid 15 has a honeycomb structure having a large number of small holes 15a having a polygonal or circular cross section passing through the interior from the base end side to the distal end side. Furthermore, as shown in FIG. 3, the internal shell 11 is structured so that the breathable solid 15 can be divided into a tip provided through a fireproof heat insulating material 16 and an end of the combustion chamber 14. It is sufficient if the permeable solid 15, which is easily damaged, can be replaced. Reference numeral 17 denotes a cylindrical housing made of ordinary steel, heat-resistant steel, cast metal, etc., which is provided around the outer periphery of the inner shell 11 at a constant interval. air supply pipe 18
is provided. Reference numeral 19 denotes a cylindrical member made of the same material as the cylindrical housing 17, which is interposed between the inner shell 11 and the cylindrical housing 17. After the supplied combustion air is guided to the tip side along the cylindrical housing 17, the internal shell 11
The combustion air flow path is turned toward the base end of the combustion chamber 14 to form a combustion air flow path that can be fed into the combustion chamber 14. Furthermore, 20 is a combustion air nozzle drilled to supply combustion air in the combustion flow path to the combustion chamber 14, and the combustion air nozzle 20 includes:
As shown in FIG. 4, a large number of air passages are provided radially in the internal shell 11, and the combustion air supplied along the combustion air flow passages is supplied into the combustion chamber 14 in a direction orthogonal to the fuel gas flow. In this way, the two can be mixed as uniformly as possible. In the above embodiment, the combustion chamber 14 is formed into a cylindrical shape, but this shape is determined by the outer shape of the air-permeable solid 15, and may be square. (Operation of the invention) When using the radiation burner of the invention constructed as described above, the combustion air supplied from the air supply pipe 18 of the cylindrical housing 17 is connected to the cylindrical housing 17 and the cylindrical The air flows through the gap formed between the cylindrical member 19 and the cylindrical member 19 and the gap formed between the cylindrical member 19 and the internal shell 11, that is, the combustion air flow path, and from there the combustion air jet hole of the internal shell 11. 20 and flows into the combustion chamber 14. The combustion air when flowing through the combustion air outlet 20 and through the gap between the cylindrical member 19 and the internal shell 11 is cooled by heat exchange with each part, and is not preheated by itself. and flows into the combustion chamber 14. On the other hand, the fuel gas is supplied to the fuel gas supply pipe 1
3 is directly supplied to the combustion chamber 14, mixed with the combustion air in a direction perpendicular to the combustion air, and homogenized. While being burned in the combustion chamber 14, this air-fuel mixture flows through the small holes 15a of the breathable solid 15 to heat the breathable solid 15, and is exposed to heat radiation from the breathable solid 15 after heating. Thus, the object to be heated is heated. (Test results of the invention) Next, Table 1 shows the results of tests on combustion suitability and thermal efficiency using the radiant burner of the invention. The main dimensions, components, and combustion conditions of the radiant burner of the present invention are as follows.・ Breathable solid; Material - ZrO ₂ , SiC ceramics Honeycomb pore shape - Square Porosity - 80% (200 mesh) Diameter - 100 mm Axial dimension (thickness) - 30 mm ・ Fireproof insulation material; Material - Ceramic fibers, filler; Material - Al ₂ O ₃ 90% or more Castable fuel: Coke oven gas (MAX: 6Nm ³ /h NOR: 3.5Nm ³ /
h) ・ Air amount: air/coke oven gas = 5 to 6 (aeration amount 30 to 36 Nm ³ /h) In addition, as a conventional radiation burner, one shown in Figure 1 is used, and the ventilation solid components,
The dimensions and combustion conditions were the same as above.

[Table] As is clear from the above test results, by using the radiant burner of the present invention, the heat load on the permeable solid and the internal shell is reduced to 1/5 of that of the conventional one, and the amount of heat dissipated is also lower than that of the conventional one. The heating efficiency is 10% (due to heat exchange with air).
I was able to improve. (Effects of the invention) As described above, the radiation burner of the invention has a wide combustion chamber, supplies fuel and air orthogonally to the combustion chamber, and mixes them as uniformly as possible. This reduces the heat load inside the combustion chamber and prevents cracks and melting due to thermal stress on the internal shell and breathable solids, and mixes the heat radiated from the internal shell. The temperature of the filling material in the internal shell is lowered by exchanging heat with the previous combustion air, and the combustion air is preheated.The internal shell itself is divided into a combustion chamber and a tip, and the inside of the tip is heated. Since the air-permeable solid is held through the fireproof heat insulating material, it has excellent effects such as improving the durability of the internal shell and greatly improving combustion efficiency.

[Brief explanation of the drawing]

Fig. 1 is a central longitudinal cross-sectional view showing a conventional radiation burner, Fig. 2 is a central longitudinal cross-sectional view showing an embodiment of the present invention, and Fig. 3 is a central longitudinal cross-sectional view showing an embodiment of the tip portion of the present invention. The enlarged view shown in FIG. 4 is a sectional view taken along the line AA in FIG. 11 is an internal shell, 13 is a fuel gas supply pipe, 1
4 is a combustion chamber, 15 is a breathable solid, 17 is a cylindrical housing, 18 is an air supply pipe, 19 is a cylindrical member, 2
0 is the combustion air nozzle.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) An internal shell comprising a wide-diameter cylindrical combustion chamber connected to the tip side of a fuel gas supply pipe, and in which a permeable solid is disposed in front of the combustion chamber; A cylindrical housing is provided around the outer periphery of the shell at regular intervals, and a combustion air supply pipe is provided at the base end of the cylindrical housing, and a cylindrical housing is provided between the inner shell and the cylindrical housing to provide combustion air. a cylindrical member capable of forming a flow passage; and a plurality of radially perforated holes in the inner shell for supplying combustion air fed along the passage to the combustion chamber perpendicular to the flow of fuel gas. A radiation burner characterized by comprising a combustion air nozzle. (2) A wide-diameter cylindrical combustion chamber connected to the tip side of the fuel gas supply pipe is provided, and an internal shell containing a breathable solid is provided in front of the combustion chamber, and the combustion chamber portion and the breathable solid are connected to each other. A utility model registration claim characterized in that the combustion chamber is divided into a distal end portion and a permeable solid is disposed inside the distal end portion via a fireproof heat insulating material so as to be connected to the end of the combustion chamber portion. A radiant burner according to scope 1.