JPH03168502A - Collision burner - Google Patents

Abstract

PURPOSE:To reduce concentration of NOX by inclining an air jet hole in a direction crossing the axis of a fuel nozzle and opening it. CONSTITUTION:An air cylinder 6 is disposed around a nozzle hole 5a opened at the end of a nozzle 5. A plurality of air jet holes 7 are so inclined to be formed concentrically in a plurality of rows on the front wall 6a of the cylinder 6 as to cross the axis X of the nozzle 5 at the center O of collision. With this structure, since combustion air is concentrated toward the center O of collision combustion, mixed with fuel particles is promoted. Accordingly, an inner EGR effect is increased, combustion characteristic is improved, and an NOX is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an impingement combustion device that burns fuel injected from a fuel nozzle by colliding with each other.

[Prior Art] As a conventional general spray combustion device, there is a so-called gun type device. In this device, liquid fuel typically weighs 7 kg/cx? It is pressurized to + and is injected and atomized by a rotating nozzle. By installing the flame holder at an appropriate distance in front of the nozzle, a vortex of combustion air and combustion spray can be generated in front of the flame holder, and the flame is maintained. Then, the air necessary for combustion is mixed in from the surrounding area, and combustion occurs.

Although this type of single spray combustion device has many advantages such as its simple structure, it also has the following disadvantages. That is,
First, in order to improve mixing with air, the flame is shaped in a combustion tube with a small diameter, causing an imbalance in the flow of combustion. Second, if you attempt to burn the fuel in a narrow space in the combustion chamber, the fuel may hit the combustion chamber walls before it evaporates, causing incomplete combustion. Thirdly, the diameter of the tip of the rotating nozzle is small, and the nozzle may be easily clogged.

Furthermore, fourthly, it is difficult to adjust the fuel injection amount.
T. D. One example of this is that it is not possible to increase the ratio of R (turn down ratio).

In order to overcome the drawbacks of the gun-type combustion apparatus, an impingement combustion apparatus has been proposed in which fuel injected from fuel nozzles collides with each other and burns. That is,
In this device, burners with fuel nozzles are placed opposite each other in the combustion chamber, and the flames collide with each other from both sides to maintain the flame, making it possible to efficiently utilize the combustion space and even out the temperature distribution. In addition, excellent combustion characteristics such as less generation of soot and NOx can be obtained due to the intense mixing effect due to collision and internal EGR (mixing effect of burned and unburned parts). (Japanese Patent Laid-Open No. 56-56511 is presented as a prior art technique in which fuel nozzles are arranged opposite each other for the purpose of mixing with combustion air and the sprayed fuel collides with each other.)
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[Problems to be Solved by the Invention] By the way, in the above-mentioned impingement combustion device, a plurality of small air injection holes are provided around the fuel nozzle from which combustion air is ejected, but the fuel flow rate is If the fuel nozzle is large, in order to secure a predetermined opening area, it is necessary to arrange the air ejection holes in multiple layers around the fuel nozzle and to distribute them at positions away from the axis of the nozzle.

However, air supplied from air jet holes located far away from the nozzle tends to mix poorly with fuel particles.
As a result, there is a shortage of combustion air in the center of the combustion chamber, and NO
There is a problem that the combustion characteristics deteriorate due to the effect of reducing the x concentration.

The present invention aims to solve the above-mentioned problems in an impingement combustion device.

[Means for Solving the Problems] In the present invention, in a combustion device in which burners each having an air nozzle provided around a fuel nozzle are disposed facing each other, the air nozzle is tilted in a direction intersecting the axis of the fuel nozzle. It is open.

[Function] With this structure, the combustion air ejected from the air nozzle is supplied so as to be concentrated around the fuel injected from the fuel nozzle in its axial direction, so that the flame from the opposing burner is The air mixing effect in the center of the combustion chamber where impingement combustion occurs is increased.

[Example] Hereinafter, one embodiment of the present invention will be illustrated and described.

FIG. 1 shows a system overview of an impingement combustion apparatus according to the present invention. In the figure, reference numeral 1 denotes a combustion vessel shaped like a cylinder, a rectangle, or an intermediate shape between the two, and a combustion chamber 2 is provided inside the combustion vessel.

In this combustion chamber 2, a heat exchanger 3 is installed in the upper part, and a pair of left and right burners 4A and 4B are installed in the lower part of the combustion chamber.
They are inserted through the side wall of the housing and are placed opposite each other in a straight line.

As shown in FIG. 2, the burners 4A and 4B are composed of a common unit in which an air injection nozzle (fuel nozzle) 5 is arranged in the center and a hollow cylindrical air 6 is arranged around the air injection nozzle (fuel nozzle). A nozzle hole 5a for injecting fuel is opened at the tip of the nozzle 5, and a front wall 6a of the air cylinder 6 located around the nozzle hole 5a is opened to inject combustion air from the air cylinder 6. A plurality of air ejection holes 7 are opened in concentric rows. Here, each air ejection hole 7 is
The opening is inclined in a direction intersecting the axis S of the air injection nozzle 5. That is, preferably, as shown in FIG. 2, each air jet hole 7 is oriented toward the intersection point (center point of collision combustion) 0 where the axis S of the nozzle 5 and the center line M of the combustion chamber 2 intersect. It will be done.

The above banner 4A. The air injection nozzle 4B is provided with a fuel inlet 5b and an air inlet 5C on the base end side. The fuel inlet 5b is connected to an oil feed pipe 9 that communicates with the oil level regulator 8 to supply fuel (arrow F), while the air inlet 5C is connected to the compressor 1 via a solenoid valve 11.
0 is connected to supply injection air (arrow ao), and fuel is sprayed from the nozzle hole 5a with this injection air. On the other hand, the air cylinder 6 has an air inlet 6b provided on the base end side, and a blower pipe 1 that communicates with the fan 13.
4 is connected, and the combustion air introduced from here (arrow a
1) is ejected from the front air ejection hole 7 in a predetermined direction.

A pressure supply pipe 15 that guides the air pressure of the injection air supplied from the compressor 10 to the air injection nozzle 5 is connected to the oil level regulator 8 through an air pressure control well 16, and the air pressure of the compressor 10 is used to maintain the oil level at a constant oil level. Fuel is supplied to the air injection nozzle 5 from the container 8. A fan 13 for feeding combustion air is communicated with the pressure pipe 15 via a fan damper 17, and as shown in FIG.
3, the amount of air supplied to the air cylinder 6 is controlled by a control device 18 in conjunction with the air pressure control valve 16.

By combining the compressor 10 and the oil level regulator 8 in this way, proportional control is realized in which fuel commensurate with the amount of injection air supplied by the compressor 1-o is supplied to the air injection nozzle 5, and control The air-fuel ratio is automatically adjusted by the device 18 according to the input. In addition, the control device ■
The air amount control of the fan 13 by 8 may be performed by frequency control instead of damper drive.

Next, the operation of the combustion device will be explained.

To start combustion, first start the fan 13, and
In the combustion chamber 2, an ignition electrode rod 19 arranged near the burners 4A and 4B is caused to spark. Next, when the compressor 10 is started and the solenoid valve 11 is opened, the internal pressure is increased in the oil level regulator 8, and the air injection nozzle 5 is supplied with fuel from the oil level regulator 8 and injection air from the compressor air. The fuel injected in a spray form from the nozzle hole 5a is ignited by a spark. The ignited flame collides with combustion air near the center of the combustion chamber 2 and is held while simultaneously mixing with combustion air ejected from the air ejection holes 7 around the nozzle. At this time, the combustion air from the air jet hole 7 is ejected so as to be concentrated toward the center O of collision combustion in the combustion chamber 2, so that mixing with the fuel particles is promoted, and the burned gas and unburned gas are The internal EGR effect, in which fuel gases collide and mix violently, is enhanced.

According to this combustion device, burners 4A and 4B are arranged oppositely,
Since the atomized fuel injected from the air injection nozzle 5 collides with each other, and the combustion air is ejected toward the center of the collision and collides with it, the mixing effect and internal g3E are achieved.
a The R effect is increased, and the combustion characteristics of impingement combustion can be further improved.

That is, even under conditions of high thermal input, the tendency for the soot and NOx concentrations to increase is suppressed. In addition, according to this device, flame can be held through impingement combustion and complete combustion can be achieved in a narrow combustion space, so the temperature distribution in the combustion chamber 2 is made uniform, and the heat exchanger 3 is small and can be used efficiently. High load combustion can be achieved.

FIG. 4 illustrates another embodiment of the air jet holes 7 provided in the burners 4A, 4B. That is, in this case, the front wall 6a of the air cylinder 6 disposed around the nozzle is shaped into, for example, an arcuate or spherical surface centered on the collision center ○ of the combustion chamber 2, and the curved front wall 6a is Air ejection holes 7 are opened.

In this way, the distances from each air jet hole 7 to the collision center O become equal, so that the concentration effect of the combustion air toward the collision center O increases. Note that the air jet holes 7 do not necessarily have to be directed strictly toward the collision center ○ of the combustion chamber 2;
In short, it is sufficient to open the fuel nozzle 5 by tilting it in a direction intersecting the axis S of the fuel nozzle 5.

Furthermore, although the above embodiments have been described using liquid fuel, gas fuel can also be used. That is, the same effect can be expected by incorporating a gas nozzle instead of the air injection nozzle and attaching a gas flow rate control valve. Furthermore, instead of the air injection nozzle, an airless nozzle such as a vari-flow nozzle may be used as the fuel nozzle. If it is difficult to use the airless nozzle, proportional control cannot be performed, but a constant input (for example, 1.0
G/H).

[Effects of the Invention] As described above, in the impingement combustion device of the present invention, by improving the direction of the air jet holes provided around the fuel nozzle, combustion is directed to the impingement combustion area in the center of the combustion chamber. The collision and mixing effect of the air used for cleaning is strengthened, and soot and NOx are
Further improvement effects can be achieved in reducing harmful emissions such as

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an impingement combustion apparatus showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of the main part (burner), and FIG. 3 is a detailed view of a part of the construction drawing. FIG. 4 is an enlarged sectional view of a burner showing another embodiment. ]... Combustion vessel, 2... Combustion chamber, 4A, 4B...
Burner, 5...Fuel nozzle, 6...Air cylinder, 7...
・Air nozzle, S... nozzle axis, O... collision center.

Claims (1)

[Claims] 1. An impingement combustion device comprising a fuel nozzle and a burner having an air nozzle provided around it and arranged facing each other, characterized in that the air nozzle is opened at an angle in a direction intersecting the axis of the fuel nozzle. .