JPH03170704A - Collision burner - Google Patents

Abstract

PURPOSE:To reduce harmful exhaust substances, such as soot or NOx by installing a plurality of air injection holes which eject combustion air at the center of a counter on a circumference which covers the counter center of a fuel nozzle. CONSTITUTION:A ring-shaped air cylinder 6 is installed at an installation position which agrees with an axis S of burners 4A and 4B (nozzle 5) on the cutter periphery of a combustion vessel 1 where the burners 4A and 4B are inserted at the opposite position. The air cylinder 6 in internally provided with an air chamber 7 that communicates with the cylinder in a peripheral direction. A pair of air intakes 6a are installed on both sides of this air cylinder 6. A plurality of air ejection apertures 8, which eject combustion air at the counter center O respectively from the air chamber 7, are installed to the inner periphery of a combustion chamber 2, which covers the counter center O of air injection nozzles 5. These air injection apertures 8 are bored at the radial rays irradiated from the center O at an equiangular span on the circumference centering on the combustion chamber's central part O and laid out in several rows up and down. This construction makes it possible to increase an air mixing action in an air collision range of the central part O of the combustion chamber.

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 is normally pressurized to 7 tg/1, and is injected and atomized by a rotating nozzle. By installing the flame stabilizer at an appropriate distance in front of the nozzle, a vortex of combustion air and fuel spray can be generated in front of the flame stabilizer, thereby holding the flame.

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 a simple structure, it also has the following disadvantages. Firstly, the flame is formed in a combustion tube with a small diameter to improve mixing with air, resulting in an uneven flow of combustion heat. 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. The problem is that it is not possible to increase the R (turn down ratio) 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 a fuel nozzle collides with each other to burn the fuel. In other words, in this device, burners with fuel nozzles are placed opposite each other in the combustion chamber so that the flames collide with each other from both sides and are held, making it possible to efficiently utilize the combustion space and even out the temperature distribution. In addition, due to the intense mixing effect caused by collision and internal EGR (mixing effect of burned and unburned parts), excellent combustion characteristics such as less generation of soot and NOx can be obtained. (Japanese Patent Application Laid-open No. 56-56511 is presented as a prior art technique in which fuel nozzles are arranged opposite each other and the atomized fuel collides with each other for the purpose of mixing with combustion air).

[Problems to be Solved by the Invention] By the way, in the conventional collision combustion apparatus, as shown in FIG.
8g, an air cylinder 32 is arranged around each fuel nozzle 3l, and combustion air (arrow A in the figure) is spouted from an air jet hole 33 consisting of a single hole (or a plurality of small holes) opened in the front side of the air cylinder 32. I have to. However, in this method of supplying combustion air from around the nozzle, the air jet hole 33
The air supplied from the combustion chamber and the fuel particles are poorly mixed, resulting in a lack of combustion air in the collision area at the center of the combustion chamber, resulting in N
There is a tendency for the combustion characteristics to deteriorate due to the effect of reducing the O x concentration.

In addition, the method in which air is ejected from around the nozzle and collides with the nozzle has a problem in that it cannot effectively suppress the irregular flow of the flame, in which the flame extends laterally and comes into contact with the inner wall surface of the combustion chamber.

Furthermore, according to this method, in order to secure the necessary air-fuel ratio, the flow velocity of the combustion air ejected from around the nozzle increases, which causes a problem that the combustion noise becomes louder.

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

[Means for Solving the Problems] In the present invention, a pair of fuel nozzles are arranged facing each other, and a plurality of air ejection holes are provided around the opposing center of the two fuel nozzles, each of which blows out combustion air toward the opposing center. That's what I do.

[Function] With this configuration, the combustion air ejected from the plurality of air ejection holes arranged around the area is concentrated toward the center of the collision area where the fuel injected from the fuel nozzle collides (the center where the nozzles are opposed to each other). This increases the air mixing effect in the collision area in the center of the combustion chamber. In addition, the combustion air that is blown out from the periphery to surround the collision area provides a flame retention effect that confines the collision flame to the center of the combustion chamber.Furthermore, the combustion air is blown out from the multiple air jet holes provided around the periphery. By distributing and supplying the combustion air, the jetting air flow velocity of the combustion air can be lowered.

[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, l is a combustion vessel formed of a cylindrical body, and a combustion chamber 2 is provided inside the combustion vessel. A heat exchanger 3 is installed in the upper part of this combustion chamber 2, while
In the lower part, a pair of left and right burners 4A and 4B are inserted through the side wall of the combustion vessel 1, and are arranged facing each other in a straight line.

Each of the burners 4A and 4B is configured such that an air injection nozzle (fuel nozzle) 5 for spraying fuel by air injection is individually arranged in the center of each burner. That is, the nozzle is not provided with an air ejection hole for ejecting combustion air around the nozzle as in the conventional case. A nozzle hole for injecting fuel is opened at the tip of each air injection nozzle 5, while a fuel inlet 5a and an air inlet 5b are provided at the base end.

Combustion vessel 1 in which the burners 4A and 4B are inserted in opposite positions
As shown in Figs. 2 and 3, there is a burner 4A on the outer periphery of the
, 4B (nozzle 5), an annular air cylinder 6 having an air chamber 7 communicating in the circumferential direction therein is provided at a mounting position that coincides with the axis S of the nozzle 5. , 4B (nozzle 5). This air cylinder 6 is provided with a pair of air inlets 6a, 6a on both sides, from which the air chamber 7 is connected.
The necessary combustion air is supplied.

On the inner periphery of the combustion chamber 2 surrounding the opposing center O of the air injection nozzles 5, 5, there are a plurality of air jet holes that blow out combustion air from the air chamber 7 toward the opposing center O (combustion chamber center). 8 is provided.

These air ejection holes 8 are opened on a circumference centered on the combustion chamber center O, on rays emitted from the center O at equal angular intervals, and are arranged in a plurality of vertical rows (three rows in the illustrated example). The vertical spacing between the rows of air jet holes 8 is preferably set as close to the fuel spray height of the air injection nozzle 5 as possible, in order to obtain a sufficient air mixing effect, as will be described later. , the distance h from the nozzle axis S is ±401T [
IT is set to 1 or lower.

The burners 4A, 4B and the air cylinder 6 are supplied with necessary fuel and air from the supply path shown in FIG.

First, the air injection nozzles 5 of the burners 4A and 4B are supplied with fuel (arrow F) by connecting the oil feed pipe 10 communicating with the oil level regulator 9 to the fuel inlet 5a, while the air inlet 5b A blow pipe 13 communicating with the compressor 11 is connected to the solenoid valve 12 to supply injection air (arrow ao).
is supplied, and this injection air sprays fuel from the nozzle hole at the tip. Further, in the air cylinder 6, a blower pipe 15 communicating with the fan 14 is connected to air inlets 6a provided on both sides, and the combustion air introduced from here (arrow a.) passes through the inside of the air chamber 7. , are ejected evenly from each air ejection hole 8.

Note that a pressure supply pipe 16 that guides the air pressure of the injection air supplied from the compressor l1 to the air injection nozzle 5 is connected to the oil level regulator 9 via an air pressure control valve l7, and the air pressure of the compressor 11 is used to maintain the oil level at a constant oil level. Fuel is supplied from the container 9 to the air injection nozzle 5. Further, the fan l4 that feeds combustion air is communicated with the pressure pipe 16 via the fan damper l8, and the amount of air supplied from the fan 14 to the air cylinder 6 is controlled by a control device such as frequency control (Fig. (not shown), the above pneumatic pressure III control valve 1
It is designed to be controlled in conjunction with 7.

By combining the compressor 11 and the oil level regulator 9 in this way, proportional control is realized in which fuel commensurate with the amount of injection air supplied by the compressor 1 is supplied to the air injection nozzle 5, and the control device The air-fuel ratio is automatically adjusted according to the input.

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

To start combustion, first start the fan 14, 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 1 is started, internal pressure is applied to the oil level regulator 9. At this time, if the solenoid valve 2 is left open, the air injection nozzle 5 receives the fuel from the oil level regulator 9 and the compressor 1 liter. Injection air is supplied from the nozzle hole, and the fuel injected in the form of a spray from the nozzle hole is ignited by a spark. Then, the ignited flame is emitted from a plurality of air jet holes 8 arranged around the combustion chamber, each with a center point 0.
While mixing with the combustion air that is evenly jetted towards the
They collide near the center O of the combustion chamber, and the flame is maintained. At this time, since the combustion air is supplied from the surroundings toward the center O of the combustion chamber, the mixing of fuel and air in the collision area is promoted, and as a result, in the combustion chamber 2, burnt gas and unburnt gas are mixed. Fuel gases are mixed efficiently and the internal EGR effect is enhanced. In addition, it has been experimentally confirmed that by setting the opening position of the air nozzle 8 within a range of ±40ITIIT1 or less from the nozzle axis S, the combustion characteristics are significantly improved by increasing the mixing efficiency. .

At the same time, combustion air blown out from around the combustion chamber to surround the collision area acts to confine the collision flame in the center of the combustion chamber 2.

Furthermore, since the combustion air can be distributed and supplied from the air jet holes 8 around the combustion chamber, it is possible to reduce the flow rate of the jet air.

Therefore, according to this combustion device, the air injection nozzle 5,
By centrally supplying combustion air from a plurality of surrounding air jet holes 8 toward the opposing center O of 5, the mixing action and internal EGR effect are increased, and the combustion characteristics of impingement combustion can be further improved. .

In particular, further improvement effects can be obtained in reducing harmful emissions such as soot and NOx. In addition, according to this device, since collision combustion can be performed while being confined in the center of the combustion chamber 2, it is possible to effectively avoid problems such as the flame extending laterally and directly exposing the inner surface of the combustion chamber to the flame. At the same time, complete combustion can be carried out in the narrow combustion space at the center of the combustion chamber, which further promotes uniformity of temperature distribution in the combustion chamber 2 and miniaturization of the heat exchanger 3, making it possible to achieve high-load combustion. . Furthermore, since the jet air flow velocity of combustion air can be reduced, an improvement effect is also exhibited in reducing combustion noise.

In addition, although the case where liquid fuel was used as object was described in the said Example, 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. When using an airless nozzle, proportional control cannot be performed, but it can be used with a constant input of 1.0 G/H, for example.

[Effects of the Invention] As described above, in the impingement combustion device of the present invention, a plurality of air ejection holes are provided on the circumference surrounding the opposing center of the fuel nozzle, each blowing out combustion air toward the opposing center. As a result, the collision and mixing effect of the combustion air in the center of the combustion chamber is enhanced, and a further improvement effect can be obtained particularly in reducing harmful emissions such as soot and NOx. In addition, impingement combustion is performed in a narrow space at the center of the combustion chamber, which prevents the flame from spreading to the combustion chamber walls, making it possible to improve the uniformity of the combustion chamber temperature, as well as reduce the combustion noise. It is also effective in reducing

[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 a schematic plan view showing the arrangement relationship between a burner and an air cylinder, and FIG. 3 is an enlarged sectional view of the air cylinder. FIG. 4 is a sectional view of a conventional opposing burner. 1... Combustion container, 2... Combustion chamber, 4A, 4B...
Burner, 5...Fuel nozzle, 6...Air cylinder, 7...
・Air chamber, 8...Air jet hole, S...Nozzle axis,
○...Center of nozzle facing (center of combustion chamber). ? Patent applicant: Noritz Co., Ltd.

Claims (1)

[Claims] 1. An impingement combustion device characterized in that a pair of fuel nozzles are arranged facing each other, and a plurality of air ejection holes are provided around the opposing center of the two fuel nozzles, each of which blows out combustion air toward the opposing center.