JPH04177007A - Collision combustion device - Google Patents

Abstract

PURPOSE:To realize a high load combustion by supplying fuel gas from a fuel gas jet-out port into the collision space of the combustion air that is jetted out from a collisiong air jet-out port and mixing and burning rapidlly the combustion air and the fuel gas under the strong turbulence. CONSTITUTION:The combustion air is jetted out at a speed that is several times as high as the combustion speed from collision air jet-out ports 24 and 24 that are mutually opposed, and the fuel gas is jetted out from a fuel gas jet-out port 22. The combustion air collides on the central axis line A of a combustion chamber 20 to create a strong turbulence. And, in this turbulent space the fuel gas is supplied to mix the air and the fuel in a short time, and the combustion proceeds violently. The flames are held stably in the space near a collision point 26, and they are not stabilized at an offset position, and the combustion efficiency is good and a high load combustion is realized. Further, under the strong turbulence the unburned gas and burned gas burn as they mix and low NOX is realized by the recirculation effect of the exhaust gas.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an impingement combustion device that collides air flows from both sides and supplies gas fuel to the collision space for combustion.

<Prior art and its problems> Conventionally, Bunsen combustion has been the mainstream in continuous combustors using gas fuel, and premix combustion has been put into practice in some cases. On the other hand, there are almost no practical examples of household combustors using diffusion combustion.

In the Bunsen combustion described above, a high concentration of N is generated in the wake of the high-temperature inner flame.
Since Ox is produced, it is difficult to realize a low NOx combustor. Furthermore, since a large space is required for secondary combustion, it is difficult to achieve high-load combustion.

On the other hand, premix combustion with a lean mixture is effective as a means of reducing NO in exhaust gas, but the flame tends to blow out.
The disadvantage is that the amount of combustion is limited. Furthermore, in premixed combustion, the flame stability range is narrow, and in practical combustors, the combustor structure for widening the flame stability range is generally complicated.

In addition, some large commercial combustors use exhaust gas recirculation (E, G), which mixes a portion of the exhaust gas with combustion air.

R) has been attempted to reduce NOx, but the device is complicated and expensive, making it difficult to apply to household combustors.

Therefore, the present invention eliminates the drawbacks of the above-mentioned prior art and achieves low NOx
The purpose of the present invention is to provide a new impingement combustion device that can realize high-load combustion and is suitable as a continuous combustor for domestic use.

<Means for Solving the Problems> In order to achieve the above object, the impingement combustion device of the present invention has the inner bottom surface of the combustion chamber shaped like a mountain with a slight upward slope from both sides toward the central axis. A plurality of fuel gas nozzles are provided along the top ridge line of the chevron-shaped inner bottom surface, and a plurality of opposing collision air nozzles having an upward angle along the ascending slope of the chevron-shaped shape are provided on both sides of the bottom of the combustion chamber. It is characterized by having been set up.

<Operation> Combustion air ejected from the opposing collision air nozzles flows along the inner bottom surface of the chevron and collides above near the top of the inner bottom surface of the chevron, producing strong disturbance. Then, the fuel gas ejected from the fuel gas ejection hole at the top of the chevron-shaped inner bottom surface is supplied to the combustion air collision space.
Under strong disturbance, air and combustion gas mix in a short time, and combustion progresses rapidly. At the same time, unburned gas in the middle of combustion
Under the above-mentioned strong disturbance, combustion is completed while being strongly mixed with the burnt gas.

In the present invention, the bottom surface of the combustion chamber is formed into a chevron shape, and the combustion air is ejected from both sides along the chevron shape, so that the combustion air is stabilized above the top of the chevron shape, that is, near the central axis of the combustion chamber. They can collide and form a collision space. Therefore, since the collision space is not biased toward one wall of the combustion chamber, the combustion chamber can be used effectively, effective combustion can be performed in a small volume, and high-load combustion can be achieved. In addition, since unburnt gas and burnt gas are mixed and combusted in the collision space, exhaust gas recirculation (E, G) is performed.

R) works to reduce NOx.

<Example> Fig. 1 is a partially sectional perspective view showing an embodiment of the device of the present invention, Fig. 2 is a sectional view of a combustion chamber, Fig. 3 is a view showing another example of the shape of the collision air nozzle, and Fig. FIGS. 4(8) and 4(B) are views showing examples of the arrangement of collision air nozzles, respectively, and FIG. 5 is a cross-sectional view showing a comparative example to the apparatus of the present invention.

An exhaust section 40 is provided at the top of the combustion can 10, and the inside of the can 10 below is a combustion chamber 20. A sound deadening material 4] is disposed in the exhaust section 40. Further, in front of the exhaust section 40, a heat exchanger 30 having a water pipe 31 is arranged.

The combustion chamber 20 consists of an elongated space having an appropriate width L2 and height H2, and is gradually reduced from both sides toward the bottom. The inner bottom surface of the combustion chamber 20 has a chevron shape 21 with a slight upward slope from both sides toward the central axis gX, and a plurality of fuel gas injection holes 22 are formed along the ridge line at the top of the chevron shape 21 in a vertical direction. It has a hole in it. 23 is a fuel gas supply pipe. Further, at the bottom of the combustion chamber 20, a plurality of pair-shaped collision air ejection holes 24, 24 are provided on both sides of the chevron-shaped shape 21 at a distance L1. 25.
25 is a combustion air supply pipe. Each pair of impinging air nozzles 24,24 is arranged at an upward angle along the ascending slope of the chevron shape 21 from both sides of the chevron shape 21, and the jetted combustion air flows along the chevron shape 21. , has a collision point 26 above the top of the chevron shape. Each fuel gas injection hole 22 is located directly below this collision point 26.

"Appropriate" width L2 and height H2 of the combustion chamber 20
This means that combustion can be completed in a space having width L2 and height H2. The distance L1 between the colliding air nozzles is set to a relatively short distance in order to ensure a strong collision of the ejected air, while the mixture of combustion air and fuel gas and unburned gas generated by the disturbance caused by the collision The above distance is a dimension that allows the mixture with burnt gas to spread sufficiently to complete combustion.

A wider distance L2 is adopted.

In the above, the opening angle of the collision air jet holes 24 is set to be about 20 degrees or less upward from the horizontal direction. Similarly, the upper limit of the ascending slope of the triangular shape 21 is about 20 degrees. When the angle is increased, the collision angle becomes smaller, and the gas quickly rises with less disturbance, resulting in poor mixing and combustion conditions.

In addition to the round hole shown in FIG. 1, the collision air outlet 24 can have a slit-like hole shown in FIG. 3, or other shapes.

Further, the collision air ejection holes 24 may be arranged in multiple rows as shown in FIG. 1, in two rows as shown in FIGS. 4(8) and 4(B), or in other plural rows.

Next, the combustion operation and effect of this device will be explained. During operation, combustion air is ejected from the opposing impingement air ejection holes 24, 24 at a speed several times the combustion speed, and fuel gas is ejected from the fuel gas ejection holes 22. The combustion air collides near the center axis X of the combustion chamber 20, causing strong disturbance. By supplying fuel gas to this turbulent space, air and fuel mix in a short time, and combustion rapidly progresses. Since the flame is stably held in the space near the collision point 26 and is not stabilized in a lopsided position, combustion efficiency is high and high-load combustion can be achieved. In addition, due to the strong disturbance, burned gas and unburned gas are mixed and combusted, so that low NO can be achieved due to the exhaust gas recirculation (E, G, R) effect.

Note that if there is no chevron shape 21 on the inner bottom surface of the combustion chamber 20,
Since the flame is stabilized by being biased toward either side wall of the combustion chamber 20, the entire combustion chamber cannot be used, and the deactivation effect of the wall becomes stronger, resulting in a large amount of unburned matter being emitted, making it difficult to perform high-load combustion. Become. Although it is difficult to perfectly balance the amount of impinging air from both sides, the chevron shape 21 of the present invention allows the flame to remain stable in the center of the combustion chamber 20 even if the amount of impinging air is slightly uneven. do.

Further, as shown in FIG. 5, between the walls 51.51 of the combustion chamber 50 that are horizontally opposed over a short distance, combustion air is ejected horizontally from the collision air ejection holes 54.54, and the fuel gas is ejected downward. When fuel gas is ejected from the hole 52 and collided for combustion, the combustion gas passes through the combustion chamber 50 before combustion is completed due to the strong upward flow, but in the configuration of the present invention, the collision space is wide. Completion of combustion is possible. Therefore, the baffle plate 55 required in the configuration diagram of FIG. 5 is also unnecessary, and the structure can be simplified.

In addition, in the embodiment, a collision diffusion combustor is used that supplies fuel gas to a collision space made of combustion air, but it is also possible to use a premix collision combustor that mixes fuel gas with collision air in advance.

Effects> The present invention has the above-described configuration and operation, and according to the collision combustion apparatus according to claim 1, fuel from the fuel gas nozzle is delivered to the collision space of the combustion air jetted from the collision air nozzle. By supplying the gas, combustion air and fuel gas can be rapidly mixed and combusted under strong turbulence. Moreover, the mountain-shaped shape of the bottom of the combustion chamber and the arrangement of the impingement air nozzle and fuel gas nozzle allow the flame to be stabilized in the center of the combustion chamber, allowing for high-load combustion with a significantly reduced overall combustion chamber volume. realizable. Moreover, combustion takes place in the center of the combustion chamber under strong turbulence.
Mixed combustion of the supplied unburned gas and burnt gas is also actively carried out, and as a result, the exhaust gas recirculation (E, G, R) effect is exhibited, and a reduction in No. can be realized.

Diffusion combustors generally have a small combustion chamber load, but in the device of the present invention, even a diffusion combustor can achieve a high load of about 2 x 10'kcal/m3h as a household combustor. In addition, the amount of NOx emissions is 2 at an excess air ratio of 1.2.
5ppm, which is less than 1/4 of that of a conventional general Bunsen combustor, and it is possible to achieve low N without using an expensive exhaust gas recirculation device.
O, can be realized.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional perspective view showing an embodiment of the device of the present invention, Fig. 2 is a sectional view of the combustion chamber, Fig. 3 is a view showing another example of the shape of the collision air nozzle, and Fig. 4 (^ ) and (B) are diagrams each showing an example of arrangement of collision air ejection holes, and FIG. 5 is a sectional view showing a comparative example with respect to the apparatus of the present invention. 10: Combustion can body 20: Combustion chamber 21: Chevron shape 22: Fuel gas nozzle 24: Collision air nozzle X: Center axis

Claims (1)

[Claims] (1) The inner bottom surface of the combustion chamber has a mountain-shaped shape with a slight upward slope from both sides toward the central axis, and a plurality of fuel gas injection holes are provided along the top ridge line of the mountain-shaped inner bottom surface, and An impingement combustion device characterized in that a plurality of pairs of impingement air nozzles each having an upward angle along the mountain-shaped ascending slope are provided on both sides of the bottom of the combustion chamber.