JPH05203125A - Burner for slurry fuel - Google Patents

Abstract

PURPOSE:To improve the operational efficiency of a burner before its ignition as well as the wear resistant properties of the burner plate and tip thereof. CONSTITUTION:A burner plug 1 is provided at its end with a burner plate 4 having fuel mixing passages formed therein to mix fuel and spray medium and further having formed at its forward end a burner tip 7 consisting of a mixing chamber 8 for receiving the mixed fuel and nozzle hole 9. The fuel mixing passages for introducing the mixed fuel therethrough into the mixing chamber 8 are so arranged as to axially intersect each other inside the mixing chamber 8 and a tip nut 10 is made of a heat resistance alloy.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a coal water slurry (CW
M) and other burners used for slurry fuel.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional burner for slurry fuel has a structure in which a burner plug 1, a burner plate 4, and a burner tip 7 are fixed by a tip nut 10 from the outer peripheral portion. The burner plug 1 is provided with a fuel supply hole 2 at the center and a plurality of spray medium supply holes 3 arranged on the circumference of the periphery of the fuel supply hole 2. The burner plate 4 communicates with the fuel supply hole 2 of the burner plug 1 and has a flow passage for distributing the fuel supplied from the fuel supply hole 2; It is provided with a plurality of first mixing chambers 6 for mixing the fuel distributed through the guide hole 5a and the spray medium supplied from the spray medium supply hole 3 of the burner plug 1. The burner tip 7 includes a plurality of first burner plates 4.
A second mixing chamber 8 for communicating with the mixing chamber 6, collecting the mixture of the fuel and the spray medium mixed in the first mixing chamber 6 in one place, and further mixing, and the mixture mixed in the second mixing chamber 8. A plurality of injection holes 9 formed at the opposite end of the burner plate 4 for spraying

A fuel such as a high-concentration coal water slurry and an atomizing medium such as compressed air which have flowed into the burner plug 1 from the outside are
Each of them flows into the burner plate 4 through the fuel supply hole 2 and the spray medium supply hole 3 of the burner plug 1. In the burner plate 4, the fuel flowing from the fuel supply hole 2 is distributed from the guide hole 5a of the fuel distribution chamber 5 toward the first mixing chamber 6, and the distributed fuel passes through the atomizing medium supply hole 3 to perform the first mixing. It is mixed with the spray medium flowing into the chamber 6 and flows into the burner tip 7. In the burner tip 7, the fuel flowing out from the first mixing chamber 6 of the planer plate 4 is collected in the second mixing chamber 8 and further mixed, and then sprayed to the outside through the injection hole 9 and burned.

[0004]

However, in the above-mentioned conventional technique, the burner plate 4 and the burner tip 7 are each formed of ceramics, and a fluid having strong abradability such as high-concentration coal-water slurry is spray-combusted. When used, the portion in contact with the slurry was severely worn, and it was necessary to replace the burner plate 4 and the burner tip 7 every several hundred hours after use.

Further, as described above, the burner plug 1, the burner plate 4, and the burner tip 7 are fixed from the outer peripheral portion by the tip nut 10, and the tip nut 10 is made of carbon steel for mechanical structure as in the conventional case. When the material is used, the coefficient of thermal expansion is large, so that a gap is created between the burner plug 1 and the burner plate 4 and between the burner plate 4 and the burner tip 7, respectively, and the mixture of fuel and spray medium leaks from this gap. However, there was a danger that coal slurry fuel would be blown out due to wear of a part that could not have been predicted at first.

Therefore, before the slurry fuel burner is ignited, it is temporarily mounted at a predetermined position, the tip of the burner is heated by being affected by the radiant heat in the furnace, and the tip nut 10 is expanded by thermal expansion. In this state, the burner is once removed, and the tip nut 10 is retightened to eliminate the gap between the burner plug 1, the burner plate 4 and the burner tip 7, and finally the burner is officially attached to burn the coal slurry fuel. I was offering. Therefore, it takes a long time to start burning the coal slurry fuel, and
Since the burner is once heated, there is a risk of burns and the like, and improvement has been desired.

In order to solve the above-mentioned problems, it has been attempted to prevent elongation due to thermal expansion by using a chip nut 10 processed with a low thermal expansion material of ceramics. In that case, the problem remains that it will crack if strong force is applied.

[0008]

In order to solve the above-mentioned problems, in a slurry fuel burner according to the present invention, the fuel and the spray are sprayed onto the tip of a burner plug for distributing and supplying a spray medium such as fuel and steam. A burner plate having a medium mixing passage is provided, and the burner plate is provided with a burner tip having a mixing chamber for receiving the mixed fuel introduced from the mixing passage and an injection hole for the mixed fuel. In a slurry fuel burner in which a burner plug, a burner plate and a burner tip are integrally fixed with a tip nut, the passage axis of the mixing passage for introducing the mixed fuel into the mixing chamber is set to intersect inside the mixing chamber, In addition, the tip nut is made of a low thermal expansion alloy.

[0009]

In the burner for slurry fuel of the present invention, the slurry-like fuel fed from the fuel feed hole of the burner plug to the mixing chamber of the burner plate is mixed with the atomizing medium and fed into the burner tip to burn the burner tip. It is further mixed inside and sprayed from the nozzle hole and burned. The mixed fuel ejected from the plurality of mixing chambers intersects in the burner tip. Therefore, the mixed fuel is violently collided in the burner tip, uniformly dispersed, sufficiently mixed, and then ejected from the injection hole. In this case, the mixed fuels ejected from the mixing chamber collide with each other in the burner tip and are evenly dispersed, so that they collide with the inner surface of the burner tip at a velocity smaller than the velocity when ejected from the mixing chamber. ， The burner tip wear is significantly reduced. Further, since the mixing in the burner tip is sufficiently performed, the spray concentration becomes uniform.

Further, since a vigorous stirring action is generated in the burner tip, the slurry flowing along the inner wall of the burner tip is sufficiently sheared to form a thin film, so that the generation of coarse particles during spraying is prevented. In addition, since the burner plug, burner plate, and tip nut that fixes the burner tip from the outer periphery are made of a low thermal expansion alloy, the coefficient of thermal expansion is small even if the burner for slurry fuel is heated by the radiant heat in the furnace. It is easy to operate because there is no need to pull out and re-tighten the tip nut.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are explanatory views showing an embodiment of the present invention, in which the same parts as those in FIG. 3 are designated by the same reference numerals.

In this embodiment, the burner plate 4 is provided with a total of six first mixing chambers 6 at equal positions in the circumferential direction. The first mixing chamber 6 extends obliquely inward toward the second mixing chamber 8, and the extension line direction of the first mixing chamber 6 intersects in the second mixing chamber 8. In this embodiment, in order to secure a sufficient dispersion, mixing, and stirring area, at the position of this intersection point C, the distance 1 between C and the tip surface of the burner tip 7 is the internal length L of the burner tip 7. For 1
It is preferable that / L is between 0.5 and 0.8.

A total of eight injection holes 9 are provided in the burner tip 7 at equal positions in the circumferential direction. In this embodiment, the burner plug 1 is a coaxial combination of the central tube member 1A and the outer tube member 1B. A flange portion 1a is provided on the tip side of the central tube member 1A, and the flange portion 1a is superposed on the burner plate 4. CWM is supplied from the conduit 12 to the fuel supply hole 2 in the central pipe member 1A, and steam is supplied to the spray medium supply hole 3 between the central pipe member 1A and the outer pipe member 1B. In the embodiment of FIG. 1, the portion of the first mixing chamber 6 upstream of the guide hole 5a has a small diameter, and the portion of the second mixing chamber 8 side thereof has a large diameter.

[0014] In the present invention, the burner plug 1 and the burner plate 4 and the burner tip nut 10 to secure the outer peripheral portion of the chip 7, for example, Fe-Ni-Co-based low thermal expansion alloy (coefficient of linear expansion 4 to 6 × 10 ^{- 6} / ° C.). Further, the burner plate 4 and the burner chip 7 may be made of the same material and made of trisilicon tetranitride ceramics having excellent thermal shock resistance or silicon carbide ceramics having excellent wear resistance. Alternatively, the burner plate 4 may be made of trisilicon tetranitride ceramics, and the burner chip 7 may be made of silicon carbide ceramics, or vice versa.

In the burner for slurry fuel constructed as described above, the tip nut 10 is sufficiently tightened with a spanner or the like before the burner is inserted into a predetermined position inside the furnace. Then, the burner for slurry fuel having such a structure is attached at a predetermined position. After this, after a series of ignition operations, combustion of the coal slurry fuel begins. First, the fuel supply hole 2 of the burner plug 1
The slurry-like fuel sent from the burner plate 4 to the first mixing chamber 6 through the fuel distribution chamber 5 is supplied to the burner plug 1
Is mixed with the spray medium fed from the spray medium supply hole 3 of the burner plate 4 to the first mixing chamber 6 and fed to the second mixing chamber 8 of the burner tip, and further mixed in the second mixing chamber 8. It is sprayed from the injection hole 9 and burned. Then, the mixture ejected from the plurality of first mixing chambers 6 intersects in the second mixing chamber 8. Therefore, the mixture violently collides in the second mixing chamber 8, is uniformly dispersed, and is sufficiently mixed and then ejected from the injection hole 9.

In this case, the mixture ejected from the first mixing chamber 6 collides with each other in the second mixing chamber 8 and is evenly dispersed, so that the velocity of the mixture ejected from the first mixing chamber 6 is Since it collides with the inner surface of the burner tip 7 at a low speed, the wear of the burner tip 7 is significantly reduced. Moreover, since the mixing in the second mixing chamber 8 is sufficiently performed, the spray concentration becomes uniform.

Further, in the second mixing chamber 8, as shown in FIG.
As shown in FIG. 5, a vigorous stirring action occurs with the collision of the ejected substances from the first mixing chamber 6, so that the slurry flowing along the inner wall of the second mixing chamber 6 is sufficiently sheared into a thin film. , The generation of coarse particles during spraying is prevented. In the present invention, it is preferable to send water, steam or air to the fuel supply hole 2 to barge the residue after the combustion of the burner for slurry fuel is stopped. In the experiment conducted by the present inventor, the life of the burner plate 4 and the burner tip 7 was about 7,000 hours or more when using the slurry fuel.

[0018]

As is clear from the above description,
According to the present invention, a burner plate having a mixing passage for mixing the fuel and the spray medium is provided at the tip of a burner plug for distributing and supplying the spray medium such as fuel and vapor, and the mixing plate introduced from the mixing passage is provided in the burner plate. In the burner for slurry fuel, the burner plug, the burner plate, and the burner tip are integrally fixed with a tip nut, the burner tip having a mixing chamber for receiving fuel and an injection hole for the mixed fuel is provided. By setting the passage axis of the mixing passage for introducing the mixed fuel into the chamber so as to intersect inside the mixing chamber and by configuring the tip nut with a low thermal expansion alloy, the mixed fuel jetted from the plurality of mixing passages is They collide in the mixing chamber and disperse evenly, and sufficient mixing is performed. Further, the collision velocity of the fuel mixture ejected from the mixing chamber against the inner surface of the burner tip becomes small and the fuel is sufficiently mixed in the burner tip, so that the wear of the inner surface of the burner tip is significantly reduced and the spray The concentration bias is reduced. Further, according to the present invention, since the slurry flowing along the inner wall of the burner tip is sufficiently sheared to form a thin film, the generation of coarse particles during spraying is prevented. Also, by using a low thermal expansion alloy for the tip nut, the thermal expansion due to heating is kept low, and there is no gap between the burner plug, the burner plate and the burner tip, and the operation before burner ignition is simplified.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a burner for slurry fuel according to an embodiment.

FIG. 2 is an explanatory diagram showing a mixed state of a mixed fuel in a burner tip of the burner.

FIG. 3 is a vertical cross-sectional view of a conventional slurry fuel burner.

[Explanation of symbols]

 1 Burner Plug 2 Fuel Supply Hole 3 Atomizing Medium Supply Hole 4 Burner Plate 5 Fuel Distribution Chamber 5a Guide Hole 6 First Mixing Chamber 7 Burner Tip 8 Second Mixing Chamber 9 Injection Hole 10 Tip Nut 12b Sleeve

Claims (1)

[Claims] 1. A burner plate having a mixing passage for mixing the fuel and the spray medium is provided at the tip of a burner plug for distributing and supplying the spray medium such as fuel and steam, and the burner plate is introduced from the mixing passage. In a burner for slurry fuel in which a burner tip formed by forming a mixing chamber for receiving the mixed fuel and forming injection holes for the mixed fuel is provided, and the burner plug, the burner plate and the burner tip are integrally fixed by a tip nut, A burner for slurry fuel, characterized in that the passage axis of a mixing passage for introducing the mixed fuel into the mixing chamber is set to intersect inside the mixing chamber, and the tip nut is made of a low thermal expansion alloy.