JPH0262771B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixed fuel spray atomizer,
Especially excellent in wear resistance. This relates to an atomizer that uses mixed fuel (COM) consisting of heavy oil and pulverized coal.

Conventionally, this type of atomizer, as shown in Fig. 1, has a steam input of 10 to 15 atg from the steam insertion port 1 and a mixed fuel of heavy oil and pulverized coal of 7 to 10 atg from the fuel insertion port 2.
The fuel is inserted at a pressure of about Kg/cm ² g and introduced into the spray mixing chamber 7 through the steam passage and the fuel passage 5 which is provided at an angle of approximately 47.5 degrees to the steam passage.
The fuel is mixed and injected from the fuel injection port 8. The aperture diameter of the spray mixing chamber 7 is approximately 6.0 mm, and since the inner surface is used without any surface hardening treatment, the fuel passage 5 in the spray mixing chamber 7 is extended as is clear from Fig. 2. In the area No. 9 above, severe abrasion damage caused by the solid components in the mixed fuel occurred, causing problems such as holes of 2 to 3 mm being formed. This wear-damaged part 9 is located in the spray mixing chamber 7.
The atomizer is held at an angle of less than 5 degrees with respect to the inner wall of the atomizer, and the atomizer often wears out locally at the same exact location, which means that the atomizer must be replaced with a new one every short period of time, resulting in a large amount of damage. This was both expensive and a major problem in terms of reliability.

An object of the present invention is to eliminate the drawbacks of the prior art described above and to provide a COM fuel spray atomizer with excellent wear resistance.

In order to achieve the above object, the present invention provides a fuel spray atomizer equipped with a spray hole including a convergence and collision area of fuel and steam, characterized in that the entire inner surface of the spray hole is treated with boron and then covered with ceramics. shall be.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

FIG. 3 is a cross-sectional view of a mixed fuel spray atomizer showing one embodiment of the present invention, and FIG. 4 is a view thereof as viewed from direction B. In the figure, this device includes conventional parts 1 to 8 shown in FIG. A cylindrical ceramic body 11 fitted as a lining to cover the hardened layer 10, and a ceramic retainer fitting plate provided at the tip of the atomizer via a bolt 14 and a retainer nut 13 that are screwed into the material 15. It is mainly composed of 12.

A thickness of about 100 to 150 μm is sufficient for the boron hardened layer 10, which is, for example,
It is formed by repeating boron treatment at 950°C for 8 hours 3 to 5 times.

In such a device configuration, the steam passing through the steam passage 6 and the mixed fuel passing through the fuel passage 5 are introduced into the spray mixing chamber 7, where they collide and mix vigorously. Since the inner surface of the spray mixing chamber 7 is covered with a ceramic body 11,
Wear damage does not occur, or even if it does occur, it is minor.

In addition, even if wear and damage occur due to long-term operation, the inner surface of the spray mixing chamber 7 is treated with boron, making it difficult to wear and damage the ceramic body 11.
Since only the atomizer needs to be replaced, there is no loss of the atomizer and it is economical.

Example 1 The inner surface of the spray hole of an atomizer made of S45C and SUS420 is treated with boron at 950°C for 8 hours three times to form a boron hardened layer, and then Al ₂ O is applied to the entire inner surface of the boron-treated spray hole. ₃ to 99%
A cylindrical ceramic body containing the material was fitted and a combustion test was conducted under the following conditions to determine the wear resistance life (hours), and the results shown in FIG. 5E were obtained.

Conditions: Flow velocity in spray hole: 190-220 m/s COM combustion amount: 3.5-4.5 t/h In Fig. 5, A to D are the same conditions as in the embodiment of the present invention, except that the anti-wear treatment conditions are different. This shows a comparative example carried out in .

The anti-wear treatment conditions for each comparative example are as follows.

A: No boron treatment B: 1 time boron treatment C: 5 times boron treatment D: No boron treatment, local ceramic lining From Figure 5, E of the present invention is overwhelmingly superior to any of Comparative Examples A to D. It is clear that the material exhibits a long wear resistance life.

In the above embodiments, the case where Al ₂ O ₃ ceramics with relatively low hardness is used is used.
It goes without saying that wear resistance is further improved when ceramics such as Si ₃ N 4 or Si 3 N ₄ are used.

According to the present invention, before the ceramic body 11 is fitted into the spray mixing chamber 7, the inner surface is previously treated with boron to form the boron hardened layer 10, so that the strength of the entire spray mixing chamber 7 is increased. Wear and damage to the atomizer body can be avoided even in emergencies such as breakage or damage to ceramics.

Note that the atomizer of the present invention is not limited to COM fuel, but is also effective as an atomizer for conventional oil-fired and coal-fired fuels.

As described above, according to the present invention,
After boron treatment is applied to the entire inner surface of the nozzle hole in the area where COM fuel and steam join, a cylindrical ceramic is fitted to create a lining structure, which improves wear resistance compared to conventional models without deteriorating combustion performance. This is a significant improvement over the law. Furthermore, since the cylindrical ceramic is removable, even if it is damaged due to long-term continuous operation, it can be operated again simply by replacing it, which provides excellent effects such as being economical.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fuel spray type atomizer for explaining the prior art, FIG. 2 is a view as viewed from direction A in FIG. 1, and FIG. 3 is a mixed fuel spray type atomizer showing an embodiment of the present invention. A cross-sectional view of the atomizer, FIG. 4 is a view taken in direction B of FIG. 3, and FIG. 5 is a diagram showing the effects of the embodiment of the present invention together with a comparative example. DESCRIPTION OF SYMBOLS 10...Boron hardening layer, 11...Ceramics (body), 12...Ceramics press fitting plate, 13...
...Press nut, 14...bolt.

Claims (1)

[Claims] 1. A fuel spray atomizer equipped with a spray hole including a convergence and collision area for fuel and steam, characterized in that the inner surface of the spray hole is treated with boron, and then the entire inner surface of the spray hole is covered with ceramics. Fuel spray atomizer.