JPH0518571Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to a surface combustion burner with a wide combustion range and excellent durability. (Prior art) As a conventional surface combustion burner, a ceramic plate with no air permeability and a large number of through holes is widely used. However, since combustion occurs only on the surface of the through holes, In addition, because the ceramic plate has high thermal conductivity, the temperature near the through-holes on the surface of the ceramic plate increases, easily causing backfire, and the mixed gas There was a problem that high-load combustion was not possible because the blow-off phenomenon was likely to occur when the ejection speed was increased. On the other hand, as shown in Japanese Utility Model Application Publication No. 60-6933, a surface combustion burner using a porous ceramic body with air permeability is also known. During operation, there is a problem that the combustion air becomes clogged with dirt and dust, which reduces ventilation, increases pressure drop, and causes uneven combustion. When using fuels such as coke oven gas, converter gas, blast furnace gas, coal gasified gas, etc. that contain 5 mg/Nm3 or ^more , the burner plate will become clogged with dust during combustion, resulting in a long burn time of several hundred hours. The only drawback was that it was durable. (Problems that the invention attempts to solve) This invention solves the conventional problems as mentioned above,
Combustion can be performed stably within a wide load range without causing flames to blow out or backfire, and the burner element is prevented from becoming clogged by dirt and dust contained in the fuel gas and combustion air. It was completed with the aim of creating a surface combustion burner that can perform stable, high-load combustion over long periods of time without causing any burns. (Means for Solving the Problems) The present invention has pores for forming short flames that communicate between the front and back surfaces sufficiently to diffuse the mixed gas of fuel gas and combustion air, and pores for forming long flames that penetrate through the front and back sides. A low pressure drop type surface combustion burner with a substantially smooth combustion surface made of a ceramic porous body having through holes, the total volume of communicating pores having an average pore diameter of 0.5 to 5.0 mm in the ceramic porous body to 75 to 5.0 mm. 95% by volume, and a large number of through holes with an equivalent diameter of 0.05 to 5.0 mm having a uniform hole shape penetrating the front and back of the ceramic porous body are substantially perpendicular to the combustion surface at intervals of 2 to 30 mm. A surface combustion burner with a high load and flashback prevention function, characterized by forming a continuous flame with long flames in the through holes and short flames in the pores on the surface of the ceramic porous body. The main points are as follows. (Example) Next, the present invention will be explained in detail with reference to illustrated examples. 1 is a burner head having a flat surface and provided with a mixed gas supply hole 2 for supplying a mixed gas of fuel gas and combustion air; 3 is a burner element attached to the opening of the burner head 1; The burner element 3 is made of a ceramic porous body 4 having pores for forming a short flame that are connected between the front and back surfaces and are sufficient to diffuse the mixed gas.
A large number of through-holes 5 for forming a long flame having a uniform hole shape are provided through the tube. This ceramic porous body 4 is made by, for example, foaming a soft polyurethane foam, removing the bubble film, impregnating it with a slurry of ceramic powder such as cordierite, alumina, mullite, or SiC, removing the excess slurry, and then drying it. It is a low pressure drop type obtained by firing, and the average diameter of the connected pores is 0.5 to 5.0 mm, and the total volume is
It shall have a content of 75 to 95% by volume. If the average pore diameter of the ceramic porous body 4 is less than 0.5 mm, clogging is likely to occur, whereas if it exceeds 5.0 mm, the strength may decrease. Further, if the total volume of pores is less than 75% by volume, the low thermal conductivity required in the present invention cannot be obtained, and if it exceeds 95% by volume, the strength will decrease. In addition, the through-holes 5 having a uniform hole shape, which are formed in large numbers in the burner element 2, have an equivalent diameter, that is, a value of (hole cross-sectional area x 4/hole inner circumference length) of 0.05 to 5.0 mm, and an interval of 2 mm. ~30mm. If the equivalent diameter of the through hole 5 is less than 0.05 mm, the burner element will become clogged with dirt and dust contained in the fuel gas and combustion air, making stable combustion impossible. On the other hand, if the equivalent diameter exceeds 5.0 mm, the strength of the burner element decreases and combustion flame blow-through phenomenon tends to occur. In addition, if the distance between the through holes 5 is less than 2 mm, the strength of the burner element will decrease, and if it exceeds 30 mm, combustion will tend to become uneven on the surface, and the burner element will be damaged by dirt and dust contained in the fuel gas and combustion air. Elements tend to become clogged. Furthermore, it is preferable that the diameter a of the through hole 5 and the diameter d of the pores of the ceramic porous body 4 satisfy a≧2d for high-load combustion. (Function) With this configuration, the air-fuel mixture supply hole 2
When a mixed gas of fuel gas and combustion air is supplied from the burner element 3 attached to the opening of the burner head 1, the mixed gas flows through the through-holes 5 for forming a long flame, each having a uniform hole shape. Since the burner element 3 is made of a ceramic porous body 4 with a flat surface and has pores for forming a short flame that are connected from the front to the back and are sufficient to diffuse the mixed gas, A large amount of mixed gas is evenly ejected from the surface of the burner element 3 between the through holes 5 and burned as a short flame. In the surface combustion burner of the present invention, the through-holes 5 have a uniform hole shape, so the main combustion is performed in the through-holes 5, making it possible to perform high-load combustion. Dirt and dust in the fuel gas and combustion air pass through, allowing stable combustion without clogging. In addition, as a result, the intermediate portion between the through holes 5 of the burner element 3 becomes red hot, and a large amount of mixed gas is burned in a uniform planar shape also in this intermediate portion, so that the portion of the through hole 5 A stable continuous flame is formed by the long flame and the short flame in the middle, and the surface combustion temperature is made uniform. Furthermore, the burner element of the present invention has a large porosity and extremely low thermal conductivity, so it also has an excellent flashback prevention function. Furthermore, the surface combustion burner of the present invention has the advantage that the pressure loss of the burner element is extremely small, and that the increase in pressure loss is extremely small even during long-term operation. In order to confirm the performance of the surface combustion burner of the present invention as described above, three types of surface combustion burners shown in No. 1 to No. 3 of Tables 1 and 2 were created, and the comparison shown in No. 4 was made. Combustion tests were conducted with the surface combustion burner as an example. As shown in the tables, the surface combustion burner of the present invention has an extremely wide combustion load range, has low pressure loss, and has little change over time.

【table】

[Table] (Effects of the invention) As is clear from the above explanation, the present invention uses long flames in the through-holes and short flames in the pores formed on the flat surface of the ceramic porous body. Since combustion is performed by forming a continuous flame over the entire surface, it can be used within a wide combustion load range from low-load combustion to high-load combustion while preventing flame blow-off and backfire due to heat conduction of the burner element. Stable combustion can be achieved.
Furthermore, this invention has an average pore diameter in the porous ceramic material.
Forming 0.5-5.0 mm communicating pores with a total volume of 75-95%, and at appropriate intervals sufficient through-holes to allow the mixed gas of fuel gas and combustion air to pass from the inlet side to the combustion surface. This not only enables stable combustion under high loads with small pressure loss in the initial state, but also allows combustion to occur within the surface pores of the porous ceramic material, reducing dust in the fuel gas and combustion air. It can be used for a long time with low pressure loss without clogging with dust. Therefore, the present invention has an extremely high practical value as a solution to the problems of conventional surface combustion burners, together with the advantage of excellent uniformity of surface combustion temperature.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention. 3... Burner element, 4... Ceramic porous body, 5... Through hole.

Claims (1)

[Scope of utility model registration request] The combustion surface is made of a ceramic porous body that has pores for short flame formation that communicate with the front and back sides and through holes that penetrate through the front and back for long flame formation, which are sufficient to diffuse the mixed gas of fuel gas and combustion air. The burner is a smooth low pressure drop type surface combustion burner, in which the total volume of continuous pores with an average pore diameter of 0.5 to 5.0 mm in the ceramic porous body is 75 to 95% by volume, and the ceramic porous body has a front and back surface. A large number of through holes with an equivalent diameter of 0.05 to 5.0 mm and a uniform hole shape are made substantially perpendicular to the combustion surface at intervals of 2 to 30 mm, and the long flame and ceramic pores are formed at the through hole portions. A surface combustion burner with a high load and flashback prevention function that performs combustion by forming a continuous flame using short flames in the pores on the body surface.