KR102236937B1 - Stage Combustion Firing Burner for Gas - Google Patents

Abstract

The present invention discloses a stage combustion type low-nox combustion burner that suppresses the generation of nitrogen oxides in the exhaust gas of a burner used in a combustion apparatus such as a boiler and enables complete combustion.
In the present invention, fuel and combustion air are supplied to the burner in a state where fuel and combustion air are rapidly and uniformly mixed for this purpose, and the flame by the second combustion burner covers the entire surface of the circumference and length of the flame ejected by the first combustion burner. By forming in a state, it is possible to effectively lower the surface temperature over the entire length of the flame, thereby suppressing the generation of thermal NOx and achieving complete combustion.
Accordingly, in the present invention, as the mixed gas uniformly dispersed and mixed is supplied to the first and second combustion burners, the flame state is stabilized and the generation of harmful gases such as carbon monoxide due to unstable combustion is prevented, as well as lowering the flame surface temperature. In addition to suppressing the generation of thermal NOx, there is an effect of improving thermal efficiency and ensuring an ideal combustion state that does not emit pollutants through complete combustion.

Description

Stage Combustion Firing Burner for Gas

The present invention relates to a stage combustion type low-nox combustion burner that suppresses the generation of nitrogen oxides in exhaust gas of a burner used in a combustion device such as a boiler and achieves complete combustion.

As is well known, the amount of NOx, which is a representative pollutant causing pollution, is determined according to the thermal characteristics of the flame according to the combustion reaction. That is, nitrogen oxides are generated as nitrogen in the air is oxidized at high temperatures during the combustion process, and industrial boilers and incinerators have been pointed out as major sources of nitrogen oxides.

These nitrogen oxides cause bronchitis, asthma, and chronic bronchitis, and are regulated as major air pollutants such as plant death due to acid rain.

Therefore, many attempts have been made to reduce the amount of nitrogen oxide generated in exhaust gas, and unlike general burners, these low-nox burners burn auxiliary flames on both sides of the flame to promote complete combustion, thereby increasing thermal efficiency and destroying the environment. It is to reduce the emission of. To illustrate this, a picture of a flame of a general burner and a low-nox burner is shown in FIG. 1.

In addition, a representative example of the recently proposed low-nox burner can be found in Korean Patent Registration No. 10-1569455 (name of the invention: hybrid low-nox burner; hereinafter referred to as'cited invention'). This cited invention guides air into the combustion chamber as shown in Fig. 2, and the combustion head is disposed at the end of the combustion chamber in the inner direction, and a fuel supply pipe is provided inside the tube connected to the combustion head and at least one on one side of the outer periphery of the tube. It is provided and has a pipe shape for injecting fuel into the combustion chamber to form a divided flame, and includes a fuel spud in which a gas inlet for inflow of combustion gas is formed in one region of the outer periphery, and when fuel is injected from the fuel spud, Using the generated pressure difference, the combustion gas is guided to the combustion chamber by inducing the combustion gas and combusting the combustion gas in the combustion chamber, and a combustion head is arranged at the end of the combustion chamber in the inner direction, and a fuel supply pipe is provided inside and connected to the combustion head. It is shaped like a tube and a pipe, and at least one is installed on one side of the outer periphery of the tube, and forms a split flame that is spaced apart from the main flame generated from the combustion head. It includes a fuel spud that injects fuel toward a region below 1000℃ in the outer periphery of the flame.

Accordingly, in the cited invention, the main flame and the split flame are separated by the separation distance between the fuel spud and the combustion head, and by promoting the absorption of radiant heat on the heat transfer surface of the combustion chamber by increasing the surface area of the flame group formed by the main flame and the split flame, It is achieved by a composite low-nox burner that lowers the amount of generation and lowers the calorific value of the injected fuel by inducing the combustion gas in the combustion chamber by using the pressure difference generated when the fuel spud injects the fuel. By fusion of staging technology, it is expected that the generation of Knox can be further lowered than that of the low-nox burner to which the existing IFGR technology is applied alone.

On the other hand, since the cited invention has a structure in which fuel and combustion air are orthogonally mixed and ignited so that they are burned at the same time, there is a high possibility that the combustion state may cause instability due to insufficient mixing of the fuel and combustion air.

In addition, by attracting combustion gas from the above-described fuel spud to form a divided flame separated from the main flame, the amount of rust generated by promoting the absorption of radiant heat on the heat transfer surface of the combustion chamber by increasing the surface area of the flame group formed by the main flame and the divided flame. Although it is expected to reduce, these fuel spuds and combustion heads are all arranged on almost the same vertical plane, and as the burner operation time elapses, the flame temperature of the main flame becomes the highest and the volume expands, resulting in the expansion of the fuel spud. Not only is there a high risk of blocking the progress of split flames, but since split flames are formed at the ends of a limited number of fuel pipes installed around the combustion burner, it does not come into contact with the entire circumference of the main flame of the combustion burner, so the flame temperature is sufficiently lowered Since it is insufficient, there is a problem that it is difficult to expect a sufficient reduction effect of thermal NOx, and there is a problem that there is a risk that the fuel spud installed around the combustion burner will backfire to the fuel pipe provided at the tip.

1. Republic of Korea Patent Registration 10-1569455 (Name of invention: complex low-nox burner)

In order to solve this problem, the present invention allows fuel and combustion air to be quickly and evenly mixed and supplied to the burner in an equalized state, and the entire surface of the circumference and length of the flame ejected by the first combustion burner is formed by the second combustion burner. It is an object of the present invention to provide a stage combustion type low-nox combustion burner by allowing the flame to be formed in an enclosed state, thereby effectively lowering the surface temperature over the entire length of the flame.

The present invention is provided with a flange body connected to a blower and into which gas fuel supplied from a separate pipe is injected, and an inclined guide arranged concentrically and a semi-circular hole installed inside the flange body to achieve this purpose. A pressure distribution plate provided with a baffle made of a conical plate body, and a distribution hole for distributing the pressure of the mixed gas of fuel and combustion air uniformly mixed while passing through the baffle, and the mixing through the pressure distribution plate A body for providing a passage so that gas is supplied to the first combustion burner for combustion and is supplied to the second combustion burner through a passage located outside the pressure distribution plate,
A first combustion burner of a standing structure, which is fastened to the main body and into which the mixed gas flows through the pressure distribution plate, and has a first flame hole formed on a vertical surface,
A second combustion burner connected to the periphery of the first combustion burner and having a second flame hole formed in a tubular body fixed in an orthogonal flame ejection direction;
The first and second inlet holes for supplying the mixed gas to the first and second flame holes of the first and second combustion burners are provided so that the mixed gas is supplied,
A stage combustion type low-nox combustion burner is provided by providing a first buffer and a second buffer in a space between the first and second flame holes and the first and second inlet holes.

In this way, according to the present invention, since the fuel is uniformly dispersed in the combustion air and the mixed gas is supplied to the first and second combustion burners, the flame state is stabilized and the combustion amount can be easily controlled.

In addition, the present invention covers the entire length and circumference of the high-temperature central flame from which the mixed gas is ignited in the first combustion burner and is in contact with the flame by the second combustion burner over a very large surface area. Since the flame is dispersed and arranged over a wide area, the flame temperature is low and the flame surface temperature of the first combustion burner is lowered to suppress the generation of thermal NOx, and the flame of the second combustion burner is the flame length of the first combustion burner and Since it is burned while in contact with the entire circumference, there is an effect of securing an ideal combustion state that does not discharge pollutants by complete combustion.

In addition, the present invention provides an inlet hole for supplying mixed gas to the flame holes of the first and second combustion burners, and a space between the flame hole and the inlet hole, thereby securing a preheating space and obtaining a pressure dispersion effect. Since it can be prevented, there is an effect that it can be safely operated.

Figure 1 is a picture of a contrast between a normal burner and a low-nox burner flame.
Figure 2 is an explanatory view showing a conventional composite low-nox burner flame state.
Figure 3 is a perspective view showing the appearance of a stage combustion type low-nox combustion burner according to the present invention.
Figure 4 is a longitudinal sectional view showing the structure of a stage combustion type low-nox combustion burner according to the present invention.
Figure 5 is a side view showing a baffle for generating uniformly dispersed mixed gas in the present invention.
Figure 6 is a perspective view of the baffle used in the present invention observed from the side.
Fig. 7 is a partial longitudinal sectional view of Fig. 4 illustrating the structure of the first and second combustion burners in the present invention.
Figure 8 is an explanatory view showing a flame generation state of the stage combustion type low-nox combustion burner according to the present invention.
9 is an exemplary view showing a boiler equipped with a stage combustion type low-nox combustion burner according to the present invention.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention with reference to the accompanying drawings.

The appearance of the stage combustion type low-nox combustion burner according to the present invention is shown in Fig. 3, and the overall configuration of a specific embodiment is shown in Fig. 4.

As can be seen from this, the present invention is connected to the blower 100 and the flange body 200 into which gaseous fuel supplied from a separate pipe is injected,

A baffle 300 made of a conical plate body installed on the inside of the flange body 200 and provided with an inclined guide 301 and a semi-circular hole 302 arranged radially,

A pressure distribution plate 401 provided with a distribution hole 402 for dispersing the pressure of the mixed gas composed of the fuel and combustion air uniformly mixed while passing through the baffle 300,

The mixed gas passing through the pressure distribution plate 401 is supplied to the first combustion burner 500 for combustion, and the second combustion burner is passed through a passage 403 located outside the pressure distribution plate 401 The main body 400 for providing a passage 403 so as to be supplied to the 600,

A first combustion burner 500 having a standing structure, which is fastened to the main body 400 to allow the gas mixture through the pressure distribution plate 401 to flow in, and has a first flame hole 501 formed on a vertical surface. ,

The second combustion burner 600 is provided with a second flame hole 601 formed in a tubular body connected to the periphery of the first combustion burner 500 and fixed in an orthogonal flame ejection direction.

In the present invention as described above, when combustion air is pumped from the blower 100 mounted on the left side of the flange body 400 and flows into the flange body 400, the mixture is mixed with the fuel flowing from the side of the flange body 400. The mixed gas passes through the baffle 300. As shown in Figs. 5 and 6, the baffle 300 is made of a conical plate, and a plurality of inclined guides 301 and semi-circular holes 302 are formed radially based on the center point of the conical shape, and the mixed gas is It passes through a plurality of inclined guides 301 at the same time.

In this process, the inclination guide 301 of the baffle 300 refracts the combustion air and fuel at a right angle different from the entry direction and discharges it in an inclined direction. Combustion air and fuel, which are simultaneously entered into 302 and whose path is refracted in this way, are forcibly stirred while rotating in the space on the right side of the drawing of the baffle 300 as shown by arrows in FIGS. 4 and 8. Accordingly, the mixed combustion air and fuel become a uniformly mixed gas mixture that is evenly mixed.

The homogenized mixed gas generated in this way flows into the main body 400 and passes through the pressure distribution plate 401 having a plurality of distribution holes 402, while a large amount of the mixed gas is transferred to the first combustion burner 500. Since it is discharged to the flame hole, the abundant fuel is ignited and burned by the known ignition device 700 while the combustion temperature is high and the flame expansion part (a) is formed.

In addition, since the second combustion burner 600 formed with a length corresponding to the total length and the circumference of the flame ejected from the circumference of the first combustion burner 500 to the right in the drawing is installed, it is provided in the second combustion burner 600 The flame formed in the second flame hole 601 is burned in a form that surrounds the entire length and circumference of the first combustion burner 500, and the flame of the second combustion burner 600 is shown in FIG. As can be seen, the surface area is several times larger than that of the first combustion burner 500, whereas the mixed gas is supplied through the passage 403, which is a limited space, so the supply pressure of the mixed gas is lowered compared to the first combustion burner 500. As the amount of combustion of the mixed gas is also reduced, the temperature of the flame contact portion (b) at which the flame of the second combustion burner 600 and the flame of the first combustion burner 500 come into contact is significantly lower than that of the flame expansion portion (a). .

As a result, the flame generated by the second combustion burner 600 has a lower temperature around the flame than the center of the flame of the first combustion burner 500, thereby suppressing the generation of thermal NOx.

In addition, in the second flame hole 601 of the second combustion burner 600, a flame airflow that is injected downward or upward is formed in the drawing, while the first flame hole 501 of the first combustion burner 500 is shown in the drawing. Since the airflow proceeding to the right is formed and they intersect at a right angle, a vortex flame portion (c) is formed that circulates in the upper right side of the drawing and the lower right side of the drawing. As a result, since the moving path of the vortex flame part (c) is long and the speed of progress in the right direction is slow, the unburned gas is completely burned to prevent the emission of carbon monoxide, thereby suppressing the emission of harmful gases and greatly improving the combustion efficiency. It becomes.

In addition to this, the present invention is for supplying mixed gas to the first and second flame holes 501 and 601 of the first and second combustion burners 500 and 600, as indicated by Fig. 7, which is a partially enlarged view of Figs. The first and second inlet holes 502 and 602 are provided to supply the mixed gas, and a first buffer 503 is provided in the space between the first and second flame holes 501 and 601 and the first and second inlet holes 502 and 602. And a second buffer 603.

Accordingly, in the present invention, the mixed gas uniformly mixed by the baffle 300 as described above passes through the distribution hole 402 of the pressure distribution plate 401, and part of the first combustion burner 500 It is ignited and burned while being ejected into the first flame hole 501 through the inlet hole 502 and the first buffer 503,

The remainder is bypassed to the outside of the pressure distribution plate 401 by fluid resistance by the pressure distribution plate 401 and passes through the second inlet hole 602 and the second buffer 603 to the second combustion burner 600. 2 Bar that is ignited and burned while being ejected into the flame hole 601,

In particular, in this process, as indicated in FIG. 7, the mixed gas is filled in the space by the first buffer 503 and the second buffer 603, so that the first and second inflow holes 502 and 602 and the first and second flame holes ( When a pressure change occurs between 501 and 601, it is stagnated in the first and second buffers 503 and 603 and acts as a buffer for the pressure change, so that a stable ignition state can be obtained and backfire can be prevented.

In addition, the present invention is formed so that the positions of the first and second inlet holes (502, 602) and the first and second flame holes (501, 601) of the first and second combustion burners 500 and 600 are alternately as shown in FIG. By doing so, it is possible to prevent backfire and to further stabilize the flame by reinforcing the possibility of dispersing the pressure by the first and second buffers 503 and 603.

In addition, the stage combustion type low-nox combustion burner according to the present invention can be installed and used in combustion facilities such as boilers of various types, and a representative example thereof is shown in FIG. 9. As can be seen from this, in the application example shown in Fig. 9, a heat exchange unit and a heat exchanger for heat recovery of exhaust gas by mounting the burner according to the present invention at the lower side and arranging a coil having a cooling water inlet and outlet at the upper side thereof. It can be installed, and it can be widely used by attaching it to various types of combustion equipment.

In the above, the technical idea of the present invention has been described together with the accompanying drawings, but this is an illustrative description of the best embodiment of the present invention, not limiting the present invention, and those of ordinary skill in the art It is obvious that anyone can modify and imitate the dimensions, shapes, and structures within the scope not departing from the scope of the technical idea of the present invention, and such modifications and imitations are included in the scope of the technical idea of the present invention.

100: blower 200: flange body 300: baffle
301: inclined guide 302: semi-circular hole 400: main body
401: pressure distribution plate 402: distribution hole 403: passage
500: first combustion burner 501: first flame hole 502: first inflow hole
503: first buffer 600: second combustion burner 601: second flame hole
602: second inflow hole 603: second buffer 700: ignition device
a: flame expansion part b: flame contact part c: vortex flame part

Claims (3)

A flange body connected to a blower and into which gas fuel supplied from a separate pipe is injected, a baffle made of a conical plate having a concentric inclined guide and a semi-circular hole installed inside the flange body, and the baffle A pressure distribution plate provided with a distribution hole for dispersing the pressure of the mixed gas, which is uniformly mixed fuel and combustion air while passing through, and the first combustion burner for combustion of the mixed gas passing through the pressure distribution plate. In addition to being supplied to the main body for providing a passage to be supplied to the second combustion burner via a passage located outside the pressure distribution plate,
A first combustion burner of a standing structure, which is fastened to the main body and into which the mixed gas flows through the pressure distribution plate, and has a first flame hole formed on a vertical surface,
A second combustion burner connected to the periphery of the first combustion burner and having a second flame hole formed in a tubular body fixed in an orthogonal flame ejection direction;
The first and second inlet holes for supplying the mixed gas to the first and second flame holes of the first and second combustion burners are provided so that the mixed gas is supplied,
A stage combustion type low-nox combustion burner, characterized in that having a first buffer and a second buffer in a space between the first and second flame holes and the first and second inlet holes.
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