JPH0642709A - Fuel-air collision type combustion device - Google Patents

Abstract

PURPOSE:To provide a fuel-air collision type combustion device capable of achieving clean combustion (substantial reduction in the generation of soot and NOx) even when a combustion load is increased, thereby also achieving a high turn down ratio (high TDR). CONSTITUTION:In the title fuel-air collision type combustion device, a pair of burners 40 ejecting fuel and primary air for combustion are provided on both sides of a combustion chamber 2a so as to opposingly face each other, and the fuel and primary air for combustion ejected from the burners on both sides are collided with each other in the vicinity of the central part of the combustion chamber 2a so as to form a collision flame. Further, in the combustion chamber, secondary combustion air introducing ports 50 are opposingly provided at positions in the downstream of the position where the collision frame is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion device, and more particularly to a collision combustion device in which a pair of burners are arranged on both sides and fuel and combustion air from both burners are burned while colliding in the combustion chamber.

[0002]

2. Description of the Related Art Conventionally, there has been provided a collision combustion device for causing fuel and combustion air from a pair of burners to collide and burn near the center of a combustion chamber. This collisional combustion device can form a flame in the central part of the combustion chamber, so that it can burn in a narrow combustion space and can achieve high-load combustion, and violent mixing action due to collision and internal EGR (mixing action of burned and unburned gas). ) Effect, clean combustion with less generation of soot and NOx can be obtained, and other excellent characteristics.

[0003]

Due to its nature, flame stability due to jet impingement is most stable in the vicinity of the stoichiometric mixture ratio, and the fuel flow rate variation range is also large. Further, as a characteristic of collision combustion, a sufficient NOx reduction effect can be obtained even under combustion conditions near the stoichiometric mixing ratio where the combustion gas has the highest temperature. However, the above conventional device has the following problems. For example, a burner as shown in FIG. 8 is adopted as the pair of burners 40 in FIG. 1, and the combustion load is increased in a system in which primary combustion air is ejected from the periphery of the fuel nozzle 41 into the combustion chamber together with the fuel. Then, the evaporation state of the fuel is reduced, and before the fuel and the primary air for combustion reach the collision region, the existing range of the local high temperature region starts to increase, so that the NOx concentration starts to increase. Even near the stoichiometric mixture ratio, soot emission is gradually observed. As described above, in the above device, in order to achieve high load and high turndown combustion while sufficiently exerting the effect of reducing NOx and soot, the state of fuel evaporation up to the collision region has a great influence. Like

Therefore, the present invention solves the above-mentioned drawbacks of the prior art, and even if the combustion load is increased, clean combustion (soot and soot) is performed.
The object of the present invention is to provide a collisional combustion device capable of achieving a significant reduction in NOx) and thus a high turndown ratio (high TDR).

[0005]

In order to achieve the above object, in the collision combustion apparatus of the present invention, a pair of burners for ejecting fuel and primary air for combustion are made to face each other on both sides of the combustion chamber. A collision combustion device in which fuel from both sides and primary air for combustion are caused to collide near the center of a combustion chamber to form a collision flame, wherein a position downstream of the position where the collision flame is generated in the combustion chamber. The first feature is that an inlet for introducing secondary air for combustion is provided in the. In addition to the first characteristic, the collision combustion device of the present invention has a second characteristic that the ratio of the fuel amount to the combustion primary air amount is 0.7 or more and 1.2 or less in terms of excess air ratio. There is. Further, in the collision combustion device of the present invention, a pair of burners for ejecting fuel and at least primary air for combustion are opposed to both sides of the combustion chamber so as to face the fuel and the primary air for combustion from both sides of the combustion chamber. A collision combustion device configured to collide in the vicinity of the center to form a collision flame, wherein a primary air jetting means for combustion and a burnt gas attracting chamber are formed around the fuel nozzle of the burner, and the fuel nozzle The third feature is that the primary air for combustion and the burnt gas are supplied as a coaxial jet together with the fuel from the surrounding area. The collision combustion device of the present invention is, in addition to the third feature,
The fourth feature is that the combustion chamber is provided with an inlet for secondary combustion air at a position downstream of the position where the collision flame is generated.

[0006]

According to the first feature, since the combustion chamber is provided with the inlet for the secondary air for combustion at a position downstream from the position where the collision flame is generated, the secondary air for combustion enters the combustion chamber. The secondary air for combustion completely burns intermediate products such as CO generated without being sufficiently oxidized in the collision combustion region. Further, according to the second feature, in addition to the action of the first feature, the ratio of the fuel amount to the combustion primary air amount is 0.7 or more and 1.2 or less in terms of excess air ratio, so that the flame The stability can be optimized, and the fuel flow rate variable range can be widened. Therefore, low NOx inherent in collision combustion
In addition to the effect of low soot, it is possible to promote complete combustion, and it is possible to stably perform clean combustion of low NOx and low soot as a whole at a high turndown ratio up to high load combustion. . According to the third feature described above,
By recirculating the burnt gas together with the fuel and the primary air for combustion from the periphery of the fuel nozzle, the effects of low NOx and low soot inherent in collision combustion can be further promoted.
Further, according to the fourth feature, in addition to the action of the third feature, by introducing the secondary air into the downstream portion, the intermediate product generated without being sufficiently oxidized in the collision combustion region is completely removed. It can burn. Therefore, at high turndown ratios up to high load combustion, overall low NO
It is possible to stably perform clean combustion of x and low soot.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall cross-sectional structural view of a collisional combustion device showing an embodiment of the device of the present invention, and FIG. 2 is a diagram showing a stable state of a flame depending on a ratio of a fuel flow rate and primary air for combustion. .

Reference numeral 1 denotes a combustion container formed in a cylindrical shape, a rectangular shape, or an intermediate shape between the two. A primary combustion chamber 2a is formed inside the combustion container, and a secondary combustion chamber 2b is formed above it, that is, downstream of the flame. ing. A heat exchanger 3 is installed above the secondary combustion chamber 2b. A pair of burners 40 is provided on both sides of the primary combustion chamber 2a.
Against each other in a straight line. A pair of burners 40 for ejecting fuel and primary air for combustion are opposed to both sides of the primary combustion chamber 2a, and fuel and primary air for combustion from both sides are made to collide near the center of the primary combustion chamber. Form a collision flame. In this embodiment, the burner 40 is the same as the conventional burner shown in FIG. That is, in FIG.
A fuel nozzle 41 is arranged on the central axis, and a hollow cylindrical primary air ejecting cylinder 42 as a primary air ejecting means for combustion is arranged around the fuel nozzle 41. A nozzle hole 41a for ejecting liquid fuel is opened at the tip of the fuel nozzle 41. Also the nozzle hole
A primary air ejection hole 42a at the tip portion of the primary air ejection tube 42 is formed in the periphery slightly before 41a.

An air cylinder 43 is attached to the base end side of the primary air jetting cylinder 42, and a primary air introducing pipe 9a is attached to the air cylinder 43. A fan 10 is installed in the primary air introducing pipe 9a.
An air tube 43 is connected to a blower pipe 11 communicating with the primary air for combustion according to the amount of combustion through the primary air introducing pipe 9a.
Sent to. The rotation of the fan 10 is controlled according to the combustion amount of the burner 40. The fuel nozzle 41 is provided with a fuel introduction port 41b and an injection air introduction port 41c on the base end side, and the fuel introduction port 41b is connected to an oil feed pipe 16 communicating with the constant oil level gauge 12 so that the liquid fuel Is supplied. Also, air injection pipe for injection
41c has a high pressure air generator 15 via a solenoid valve 13 and a control valve 14.
A high-pressure blower pipe 19 communicating with is connected. On the other hand, a pressure transmission pipe 17 is connected to the upper part of the constant oil level gauge 12 via the solenoid valve 13. A pair of secondary air inlets 50 face each other on both sides of the secondary air combustion chamber 2b.
The secondary air inlet 50 is provided with a secondary air hole 51.
A secondary air introducing pipe 9b is connected to the secondary air introducing port 50 from a fan 10 via a blower pipe 11.

In combustion, first, the fan 10 is started, the ignition electrode rod 18 is sparked, then the high pressure air generator 15 is started, and the control valve 14 is operated to control the air amount and pressure. . The control valve 14 controls the flow rate of fuel introduced into the fuel nozzle 41 and the amount of injection air. That is,
When the solenoid valve 13 is opened, it passes through the high pressure blower pipe 19 and the fuel nozzle.
Along with the injection air being introduced into 41, pressure is also applied to the inside of the oil level gauge 12 via the pressure transmission pipe 17, and the fuel is introduced into the fuel nozzle 41 through the oil feeding pipe 16 according to the pressure. It
The supplied fuel is injected into the nozzle hole 41a by the air for injection.
It is ejected in the form of a spray from and is ignited by a spark.
On the other hand, the primary air for combustion is guided by the primary air introduction pipe 9a connected to the air cylinder 43, and the primary air ejection cylinder is ejected from the air cylinder 43.
It is sent to 42 and is ejected from the primary air ejection hole 42a.

The atomized fuel that has ejected is the primary air ejection hole 42a.
Evaporate and mix in the primary air jet for combustion from. The jet of primary air for combustion also induces burnt gas in the surroundings, and these air-fuel mixtures collide from both sides in the central collision area of the primary combustion chamber 2a, vigorously mix and burn, and soot and soot are generated. NOx
Combustion with less emission of. In this case, by setting the ratio of the injected fuel amount and the combustion primary air amount to be 0.7 or more and 1.2 or less in terms of excess air ratio, which is near the stoichiometric mixing ratio, as shown in FIG. The flame can be obtained, and the variable range of the fuel flow rate, that is, the turndown ratio (TDR) can be largely adopted. In addition, as a feature of collision combustion,
A sufficient NOx reduction effect can be obtained even under combustion conditions near the stoichiometric mixing ratio where the combustion gas has the highest temperature. However, CO emission concentration is high near the stoichiometric mixture ratio.
In addition, since the combustion conditions are near the stoichiometric mixture ratio, in this example where the NOx concentration and soot tend to increase as the combustion load increases, in the downstream of the primary combustion chamber 2a where collision combustion is performed,
Since the secondary air for combustion is introduced into the secondary combustion chamber 2b from the secondary air inlet 50, intermediate products such as CO generated without being sufficiently oxidized in the collision combustion region are completely burned. Therefore, in addition to the effect of low NOx and low soot inherent in collision combustion, complete combustion can be promoted, and at the high turndown ratio up to high load combustion, low NOx and low soot as a whole can be achieved. Clean combustion can be stably performed.

FIG. 3 is a configuration diagram of a burner showing an example in which a burner different from the above embodiment is used. FIG. 3A is a sectional configuration diagram,
(B) is a left side view. The burner 40 of this example has a hollow cylindrical shape 1 around the fuel nozzle 41 as a primary air jetting means.
The primary air chamber A for combustion is formed by arranging the secondary air ejection cylinder 42, and the burned gas attracting mixing cylinder is provided around the primary air ejection cylinder 42.
44 are arranged to form the burnt gas attraction chamber B. A plurality of induction holes 44b are provided on the cylinder wall of the burnt gas induction mixing cylinder 44. Other configurations are the same as those described for the burner shown in FIG. Members and elements having the same function are designated by the same reference numerals, and description thereof will be omitted. In this embodiment, fuel is ejected from the combustion nozzle 41 and the primary air for combustion is 1
When jetted from the primary air chamber A for combustion in the secondary air jetting cylinder 42, the inside of the burnt gas attracting chamber B in the burnt gas attracting / mixing cylinder 44 is made to have a negative pressure, which causes combustion from the attracting hole 44b. The burnt gas in the room is drawn in and is jetted together from the burnt gas spouting hole 44a at the tip of the burnt gas attracting and mixing cylinder 44. That is, from the periphery of the fuel nozzle 41, the combustion primary air and the burned gas are jetted and supplied as a coaxial jet into the primary combustion chamber 2a together with the fuel. The mixture of fuel, primary air for combustion, and burnt gas that has been ejected also attracts burnt gas in the surroundings and vigorously mixes and burns in the collision area in the center of the primary combustion chamber 2a, producing soot and NOx. Burn with low emissions. By recirculating the burned gas together with the fuel and the primary air for combustion from the periphery of the fuel nozzle, the effect of low NOx and low soot inherent in collision combustion can be further promoted. Therefore, it is possible to stably perform clean combustion with low NOx and low soot as a whole at a high turndown ratio up to high load combustion.

4A and 4B are configuration diagrams of a burner showing an example in which a burner different from the above embodiment is used. FIG. 4A is a sectional configuration view and FIG. 4B is a left side view. In this embodiment, as shown in FIG.
Instead of the primary air jet cylinder 42 in the burner 40 shown in
A plurality of primary air ejection pipes 45 are provided around the ejection nozzle 41 to serve as primary air ejection means. Other configurations are shown in FIG.
Since the configuration is the same as that described above, the same member,
The same reference numerals are given to the elements, and the description will be omitted. The function and effect are also the same as those in the example described with reference to FIG.

In the above embodiments, the liquid fuel was used as the object, but gas fuel may be used. In this case, a similar effect can be obtained by using a gas nozzle as the combustion nozzle and attaching a gas flow rate control valve. Further, as the fuel nozzle 41, in addition to the air injection nozzle, another suitable nozzle such as an ultrasonic nozzle, a return type nozzle, a constant input airless injection nozzle, or the like can be used.

Regarding the secondary air inlet 50, in addition to the configuration shown in FIG. 1, as shown in FIG. 5, the primary combustion chambers 2a and 2a
The space between the secondary combustion chamber 2b and the secondary combustion chamber 2b may be throttled by the secondary air inlet 50. Further, the configuration of the secondary air inlet 50 as shown in FIGS. 6 and 7 may be adopted.

[0016]

The present invention has the above-described structure and operation. According to the collision combustion device of the first aspect, the combustion chamber 2 is provided at a position downstream from the position where the collision flame is generated.
Since the secondary air inlet is provided, it is possible to completely combust intermediate products such as CO remaining in the collisional combustion by the secondary combustion air, and thus the low NOx and soot inherent in the collisional combustion can be achieved. In addition to the effect, it is possible to promote complete combustion, and it is possible to stably perform clean combustion with low NOx and low soot as a whole at a high turndown ratio up to high load combustion. According to the collision combustion device of the second aspect, in addition to the effect of the configuration of the first aspect, the ratio of the fuel amount and the primary air amount for combustion is 0.7 or more and 1.2 or more in terms of excess air ratio. By setting the following, the flame stability can be made the best and the variable range of the fuel flow rate can be widened. Further, according to the collision combustion device of the third aspect, the combustion primary air jetting means and the burnt gas attraction chamber are formed around the fuel nozzle, and the combustion primary air is supplied from around the fuel nozzle together with the fuel. Since the burnt gas and the burned gas are supplied as a coaxial jet, the low NO that is inherent in collision combustion
The effect of x and low soot can be further promoted. Therefore, in addition to the effect of low NOx and low soot inherent in collision combustion, complete combustion can be promoted, and at the high turndown ratio up to high load combustion, overall low NOx and low soot cleanliness is achieved. The stable combustion can be performed.
Further, according to the collision combustion device of the fourth aspect, in addition to the effect of the configuration of the third aspect, by introducing the secondary air into the downstream portion, the collision combustion region is not sufficiently oxidized. The generated intermediate product can be completely burned.

[Brief description of drawings]

FIG. 1 is an overall cross-sectional configuration diagram of a collision combustion device showing an embodiment of the device of the present invention.

FIG. 2 is a diagram showing a stable state of a flame depending on a ratio between a fuel flow rate and primary air for combustion.

FIG. 3 is a configuration diagram of a burner showing an example using different burners.

FIG. 4 is a configuration diagram of a burner showing an example using a different burner.

FIG. 5 is a cross-sectional configuration diagram of a collision combustion device showing an example having another secondary air introduction port.

FIG. 6 is a cross-sectional configuration diagram of a collision combustion device showing an example having still another secondary air introduction port.

FIG. 7 is a sectional configuration diagram of a collision combustion device showing an example having another secondary air inlet.

FIG. 8 is a sectional view showing an example of a general burner attached to a conventional device.

[Explanation of symbols]

 1 Combustion container 2a Primary combustion chamber 2b Secondary combustion chamber 40 Burner 41 Fuel nozzle 42 Primary air jet cylinder 44 Burned gas attracting and mixing cylinder 45 Primary air jet pipe 50 Secondary air inlet

Claims (4)

[Claims] 1. A pair of burners for ejecting fuel and primary combustion air are opposed to both sides of the combustion chamber, and fuel and primary air from both sides are made to collide near the center of the combustion chamber. Collision combustion apparatus configured to form a collision flame by means of a combustion chamber, wherein an inlet for introducing secondary air for combustion is provided in the combustion chamber at a position downstream from a position where the collision flame is generated. apparatus. 2. The ratio between the fuel amount and the primary air amount for combustion is
The collision combustion device according to claim 1, wherein the excess air ratio is 0.7 or more and 1.2 or less. 3. A pair of burners for injecting fuel and at least primary air for combustion are provided facing both sides of the combustion chamber.
A collision combustion device in which fuel and primary air for combustion from both sides are caused to collide in the vicinity of the center of a combustion chamber to form a collision flame, and the combustion combustion device is provided around a fuel nozzle of the burner.
A collisional combustion device comprising a secondary jetting means and a burnt gas attracting chamber, wherein primary combustion air and burned gas are supplied as a coaxial jet together with fuel from the periphery of the fuel nozzle. 4. The combustion chamber is provided with an inlet for secondary combustion air at a position downstream of a position where an impact flame is generated.
The collision combustion device according to 1.