JPH0614718U - Thermal shock burner diffuser - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a heat-resistant shock burner diffuser in which the diffuser cone is not destroyed by thermal shock even when the combustion of the burner is stopped. [Structure] A plurality of cone element pieces 6 are provided at the tip of the straight body portion 1.
While installing the ceramic diffuser cone 5 consisting of, on the back side of the diffuser cone 5,
A metal straightening plate 9 is attached to prevent the combustion air from directly hitting the cone element piece 5. This prevents the cone element piece 5 from being rapidly cooled when combustion of the burner is stopped, and the thermal shock is mitigated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improvement in a thermal shock burner diffuser used in, for example, a boiler of a thermal power plant.

[0002]

[Prior art]

 A member called a burner diffuser is used in a boiler or the like of a thermal power plant in order to inject fuel to generate a flame. In this burner diffuser, a diffuser cone that spreads in a conical shape is attached to the tip of the double-cylinder straight body part, which includes an inner cylinder for injecting heavy oil as fuel and an outer cylinder for supplying combustion air. It is a thing.

Since such a burner diffuser becomes a high temperature of 1100 ° C. or higher due to radiant heat from a flame, even if a cobalt-based alloy having excellent heat resistance is used, it easily deteriorates due to heat, and after being used for about one year It had to be replaced. Therefore, as shown in Japanese Utility Model Laid-Open No. 61-58531 and Japanese Utility Model Laid-Open No. 1-151026, the diffuser cone with the highest temperature is made of ceramics composed of a plurality of cone element pieces. It has been proposed to prevent thermal degradation and thermal stress cracking.

The burner diffuser provided with the ceramic diffuser cone as described above exhibits excellent heat resistance characteristics in a state where the boiler is continuously operated. However, when the combustion of some burners is stopped in order to reduce the output of the power generation boiler when the power demand decreases at night, etc., the diffuser cone made of ceramics at the point where the combustion was stopped may crack. It was The cause is that even though the surface of the stopped diffuser cone facing the flame is heated to 1100 ° C or higher by the radiant heat from other burning burners, its back surface is rapidly cooled by the combustion air when the combustion is stopped. This is because the ceramic shock is destroyed by the thermal shock at that time.

[0005]

[Problems to be solved by the device]

 The present invention has been completed in order to solve the above-mentioned conventional problems and provide a thermal shock burner diffuser in which the diffuser cone is not destroyed by thermal shock even when combustion is stopped. .

[0006]

[Means for Solving the Problems]

 The heat-resistant shock burner diffuser of the present invention made to solve the above-mentioned problems has a double barrel-shaped straight body portion including an inner cylinder for fuel injection and an outer cylinder for supplying combustion air. A ceramic diffuser cone consisting of multiple cone element pieces was attached, and a metal straightening plate was installed on the back side of this diffuser cone to prevent combustion air from directly hitting the cone element pieces. It is what

[0007]

[Action]

 Since the thermal shock burner diffuser of the present invention has a ceramic diffuser cone composed of a plurality of cone element pieces, it exhibits excellent heat resistance characteristics as in the past. Moreover, the thermal shock burner diffuser of the present invention prevents the combustion air from directly hitting the cone element piece by the metal straightening plate attached to the back side of the diffuser cone, so that it can be partially used at night when the power demand decreases. Even when the combustion of the burner is stopped, the diffuser cone is not rapidly cooled by the combustion air and the ceramic diffuser cone is not cracked.

[0008]

【Example】

 Hereinafter, the present invention will be described in more detail with reference to the illustrated embodiments. 1 and 2, reference numeral 1 denotes a straight body portion made of metal such as stainless steel, and the straight body portion 1 includes an inner cylinder 2 and an outer cylinder 3. The inner cylinder 2 is for ejecting fuel such as heavy oil. The outer cylinder 3 has a plurality of cavities 4 and is for supplying combustion air from around the inner cylinder 2 through these cavities 4.

Reference numeral 5 denotes a ceramic diffuser cone attached to the tip of the straight body portion 1. The diffuser cone 5 of the embodiment is composed of four cone element pieces 6, and each cone element piece 6 has a shape in which a conical surface having a central hole is divided into four equal parts as shown in FIG. The cone is not limited to be divided into four, and a plurality of cone element pieces 6 can be formed according to the size. Further, each cone element piece 6 has a mounting leg portion 7 at the lower center thereof, and by inserting this into the radial groove 8 formed in the outer cylinder 3, the cone-shaped diffuser cone 5 is formed. ing.

In the present invention, a straightening vane 9 made of metal such as stainless steel is attached to the back side of the ceramic diffuser cone 5 attached to the tip of the straight body portion 1 in this way. The current plate 9 is also a cone having a cone angle substantially the same as that of the diffuser cone 5, and is attached using the attachment legs 7 of the above-mentioned cone element pieces 6 as shown in FIG. The diameter of the straightening vane 9 may be substantially equal to the diameter of the diffuser cone 5.

In the heat shock-resistant burner diffuser of the present invention thus constructed, the diffuser cone 5 that receives high-temperature radiant heat from the inside of the boiler is made of ceramics, which has excellent heat resistance, and therefore is as excellent as the conventional one. Exhibits heat resistance. Moreover, in order to prevent the rectifying plate 9 from deflecting the combustion air to the outside and directly hitting the cone element piece 6, the ceramic cone element piece 6 is rapidly cooled from the back side even when the burner is stopped at night. Therefore, the thermal shock received by the cone element piece 6 can be alleviated. In order to confirm the effects of the present invention described above, the digestion state of the boiler was simulated using a combustion experimental furnace, and the effect of mitigating the thermal shock temperature on the surface of the ceramic diffuser cone 5 according to the present invention was confirmed. The result is shown in FIG.

[0012]

[Table 1]

As shown in Table 1 above, in the case of the conventional case without the baffle plate 9, the surface of the diffuser cone 5 becomes 639 ° C. after 5 minutes of extinguishing, and the temperature drop of 477 ° C. occurs. In the case of the present invention in which the current plate 9 is provided, the temperature drop is 419 ° C., and there is a difference of about 60 ° C. between the two. According to the analysis of another experiment using the finite element method, this temperature difference of 60 ° C. corresponds to a tensile stress value of about 180 kg / cm ² . If the ceramics used in the diffuser cone 5 is the bending strength a silicon carbide ordinary silicon nitride bond is to be 500~600kg / cm ^2, since the breaking strength becomes 225~27 0kg / cm ^2, It can be seen that the difference in tensile stress of 180 kg / cm ² due to the temperature difference of 60 ° C. has an extremely large meaning in protecting the ceramic diffuser cone 5 from damage due to thermal shock.

[0014]

[Effect of device]

 As explained above, the thermal shock burner diffuser of the present invention has a metal straightening vane attached to the back side of the ceramic diffuser cone to prevent the combustion air from directly hitting the cone element piece. It has the same excellent heat resistance as before, and the diffuser cone is not cooled from the backside by the combustion air even when the combustion of some burners is stopped at night, etc. It is possible to prevent cracking due to thermal shock. Therefore, the present invention is of great value as a thermal shock burner diffuser that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention.

FIG. 2 is a partially cutaway plan view showing an embodiment of the present invention.

FIG. 3 is a perspective view of a cone element piece.

[Explanation of symbols]

 1 straight body part 2 inner cylinder 3 outer cylinder 5 diffuser cone 6 cone element piece 9 straightening plate

Claims (1)

[Scope of utility model registration request] 1. A diffuser cone made of ceramics composed of a plurality of cone element pieces is attached to the tip of a double-cylinder-shaped straight body portion including an inner cylinder for fuel injection and an outer cylinder for supplying combustion air. At the same time, a thermal shock burner diffuser is equipped with a metal straightening vane on the back side of the diffuser cone to prevent the combustion air from directly hitting the cone element pieces.