KR100247387B1 - Low-producing burner of nox equipped with swirl vane - Google Patents

Abstract

The present invention relates to a low nitrogen oxide producing burner using a two-stage combustion method and an exhaust gas recirculation method. In the related art, the combustion area is divided into a region having a lot of air and a region having a low amount of rotational movement of the secondary air. As the phenomenon is not apparent, secondary air and tertiary air meet in the initial combustion zone to form a high combustion temperature, and the strength of internal recirculation flow by the primary air is weak so that the effect of inhibiting the formation of nitrogen oxides is not obvious. Although there are many problems such as the insufficient amount of air to be sent to the downstream combustion zone, the reburning of the unburned portion is not performed smoothly. However, the present invention provides a flow splitter and a burner outer cylinder length to improve the air flow and the combustion atmosphere in the combustion zone. Extends to the burner neck, expands the radius at the end, and connects the swing generator and the injection nozzle to the end of the burner. It is improved by the structure and shows uniform temperature distribution in the whole combustion zone. Therefore, the formation of high temperature nitrogen oxide is suppressed and the nitrogen component contained in the fuel is reduced to the form of nitrogen molecules rather than nitrogen oxides. Since the generation of dust is suppressed by realization of the complete combustion, there is an excellent effect of reducing the installation cost and operating cost because a separate exhaust gas reprocessing facility such as a nitrogen oxide reduction catalyst or an electrostatic precipitator is unnecessary or its capacity can be reduced. .

Description

Nitrogen oxide low production burner with swing generator

The present invention relates to a nitrogen oxide low production burner, and more particularly, combustion air is divided into primary air, secondary air, and tertiary air by the burner outer cylinder and the flow splitter, respectively. The present invention relates to a nitrogen oxide low production burner utilizing a two-stage combustion method and a flue gas recirculation method that are rotated by vanes and discharged and burned.

Environmental pollutants generated by the burning of fossil fuels include nitrogen oxides (NOx), sulfur oxides (SOx), carbon monoxide, hydrocarbons, unburned fractions, and these environmental pollutants cause various environmental hazards. It is gradually being strengthened.

The methods for reducing such environmental pollutants can be broadly classified into pretreatment by the treatment of the fuel itself, improvement by the combustion technology itself, and post-treatment by the reprocessing of the combustion gas after it is generated. .

For example, in the case of sulfur oxides, since the sulfur is contained in the fuel, the sulfur component in the fuel is removed by the pretreatment method to suppress the generation of sulfur oxides. Sulfur oxides are removed by combustion gas reprocessing.

However, in the case of nitrogen oxides, not only fuel NOx produced during combustion by nitrogen components contained in the fuel, but also nitrogen oxides in the air are formed by reacting with oxygen in a high temperature region of 1500 degrees or higher. (Thermal NOx) is produced largely and its production varies greatly depending on the combustion environment, and when the generated nitrogen oxide is treated by the combustion gas reprocessing method, not only is it expensive but also the process is difficult, so the combustion environment is reduced. Many methods to improve the production of nitrogen oxides have been sought.

When describing nitrogen oxide reduction technology through improving combustion environment, the exhaust gas is mixed with combustion air or through a separate nozzle to supply exhaust gas having a higher ratio of nitrogen and lower oxygen ratio by using a separate nozzle. Exhaust gas recirculation method for suppressing the formation of high temperature nitrogen oxide, and two-stage combustion method for suppressing the rapid temperature rise of the front end of the flame by performing the main combustion in an air shortage state and reburning the unburned powder at the rear end of the combustion zone.

6 is a cross-sectional view of a conventional nitrogen oxide low production burner.

In the conventional nitrogen oxide low production burner, in order to reduce the amount of nitrogen oxide produced, the combustion zone is separated into an air lean zone and an excess zone, and the injection of fuel is performed in the combustion air lean zone to perform incomplete combustion in the initial combustion zone. The combustion fraction is completely combusted by reacting in the downstream combustion zone, which is the excess air area, by the air sent to the downstream combustion zone, which is classified by the flow dividing cylinder 6 ', so that the unburned fraction is reduced, and the combustion zone is separated, thereby reducing the overall combustion. Since the temperature in the combustion zone is lowered, the production of hot nitrogen oxides is suppressed.

The flow split cylinder 6 'is a secondary air 10' passing through the primary vane 4 'and a secondary vane 5' through which the combustion air is blown through the primary vane 4 '. Separate it with

The primary air 9 'and the secondary air 10' separated by the above process are sent to the main combustion reaction zone and the downstream combustion zone, respectively.

However, in the conventional nitrogen oxide low production burner, since the rotational momentum of the primary air (9 ') is small, the distribution phenomenon that separates the combustion zone into a large air space and a small air zone does not appear clearly, thereby forming a high combustion temperature. There are many problems such as the effect of inhibiting the formation of high temperature nitrogen oxides is not clear and the amount of air sent to the downstream combustion zone is insufficient, so that the unburned fraction is not actively burned.

The present invention has been made to solve the above problems, and for the purpose of providing a low nitrogen oxide burner that can reduce the production of nitrogen oxide and unburned dust generated during the combustion process in an industrial boiler. do.

The purpose is to extend the length of the flow split and burner casings to the burner neck and to increase the radius at the ends, to improve the flow of air and the combustion atmosphere in the combustion zone, and to bring the swirl generator and the injection nozzle to the ends of the burner casings. It can be achieved by the configuration of the present invention, characterized in that installed in, with reference to the accompanying drawings will be described in detail below.

1 is a cross-sectional view of a nitrogen oxide low production burner according to the present invention,

2 is a cross-sectional view showing the flow of combustion air in the burner according to the present invention,

3 is an enlarged perspective view of the swing generator of FIG. 1,

4 is a graph showing the temperature distribution in the furnace of the present invention,

5 is a graph showing the emission characteristics of nitrogen oxides and dust generated in the burner according to the present invention,

6 is a cross-sectional view of a conventional nitrogen oxide low production burner.

Explanation of symbols for main parts

1: injection nozzle 2: swing generator

3: Burner barrel 4,4 ': 1st vane

5,5 ': 2nd vane 6,6': flow split container

7: burner tile 8: burner neck

9,9 ': Primary air 10.10': Secondary air

11: tertiary air 12: initial combustion zone

13: intermediate combustion zone 14: wake combustion zone

1 is a cross-sectional view of a nitrogen oxide low production burner according to the present invention.

Looking first at the configuration of the present invention, the present invention is the center of the injection nozzle (1) in which the fuel is injected, the length of the swing generator (2) and the burner neck (8) combined with the injection nozzle (1) Burner outer cylinder (3), the radius of the terminal is expanded, the primary vane (4) for turning the inlet air, and the air orbited in the primary vane (4) the primary air (9) and secondary air ( 10) and the length extending to the burner neck (8) and the flow split cylinder (6) parallel to the burner outer cylinder (3), the secondary vanes (5) for turning the secondary air (10), It is composed of a burner tile (7) surrounding the outer of the burner.

Figure 2 shows the flow of combustion air in a nitrogen oxide low production burner according to the present invention, the operation of the present invention by the above configuration will be described below.

Combustion air used in the nitrogen oxide low production burner according to the present invention is introduced into the primary air (9), secondary air (10) and tertiary air (11), respectively, the primary air (9) is 1 It is combined with the unburned fraction in the internal recirculation flow field because it is discharged while maintaining the turning momentum along the flow dividing barrel (6) extending from the vane (4) to the burner neck (8) to reach the wake of the flame. To achieve complete combustion, and the secondary air 10 is pivoted by the secondary vanes 5 to maintain the turning momentum along the passage between the burner outer cylinder 3 and the flow split cylinder 6, the length of which is extended. It is discharged to maintain the turning strength of the primary air (9) and forms the internal recirculation zone flow field in the initial combustion zone 12 together with the primary air (9).

3 is an enlarged perspective view of the swing generator of FIG. 1.

Since the tertiary air 11 is introduced into the burner outer cylinder 3 as the main combustion air, the tertiary air 11 is turned and discharged by the swirl generator 2 having a shape as shown in FIG. In addition, it serves to maintain the strength of the internal recirculation flow formed by the secondary air (10).

In addition, the fuel injection in the nitrogen oxide low production burner according to the present invention is made in the internal recirculation area formed by the secondary air 10 through the injection nozzle (1) located at the end of the burner outer cylinder (3) burner shear In the initial combustion zone 12, the air is insufficient and the fuel is saturated, and the supplied fuel is incompletely burned, so that a sudden rise in the temperature of the flame shear is suppressed, and in the fuel in the internal recirculating flow field in the intermediate combustion zone 13 Since the contained nitrogen component is not bonded to the oxygen molecules in the combustion air and is reduced in the form of nitrogen molecules instead of nitrogen oxides, the production of fuel nitrogen oxides is suppressed.

3 is a graph showing the temperature distribution in the furnace of the present invention.

In the present invention, the burner outer cylinder 3 and the flow dividing cylinder 6 have a shape in which a radius is enlarged at an end thereof, so that the combustion region in the furnace is enlarged as a whole, and as described above, in the initial combustion region 12 of the burner front end. Since the air is insufficient and the fuel is saturated and the temperature rise in the main combustion region is suppressed, it has a uniform temperature distribution in the entire combustion region as shown in FIG. 3 and generates high temperature NOx generated in a high temperature combustion atmosphere. The production of is also suppressed.

4 is a graph showing the emission characteristics of nitrogen oxides and dust generated in the burner according to the present invention.

As shown, it can be seen that the total amount of nitrogen oxides generated in the burner according to the present invention is significantly reduced compared with the related art, and the amount of dust due to unburned dust is also significantly reduced through realization of complete combustion.

The effect of the present invention is to extend the length of the burner outer cylinder and the flow split cylinder to the end of the burner neck as described above, and to discharging the tertiary air strongly by the swirl generator, thereby reducing the loss of the turning momentum of the primary air And the secondary air also maintains the rotational momentum and is discharged, thereby promoting the formation of an internal recirculation flow field, delaying the combustion reaction of the fuel in the air lean internal recirculation flow field, suppressing the generation of nitrogen oxides, and forming a flame in the initial combustion zone. Since the stabilizing effect of the secondary air is excellent in maintaining the turning strength of the primary air, the primary air is sufficiently supplied to the wake of the flame, and the generation of dust is suppressed by the realization of complete combustion. If the length of the outer cylinder does not extend to the end of the burner neck as in the present invention, the turning effect of the secondary air is reduced by mixing with the tertiary air. This makes it difficult to form stabilized salts by turning the secondary air, thus limiting the reduction of nitrogen oxides.However, the end of the outer burner and the flow splitter can be extended to the end of the burner neck to achieve stable combustion. Is produced in the internal recycle zone, and thus shows uniform temperature distribution in the entire combustion zone, suppressing the production of high temperature nitrogen oxides, and reducing the nitrogen content in the fuel in the form of nitrogen molecules instead of nitrogen oxides. Significantly reduced.

Therefore, since the nitrogen oxide low production burner according to the present invention reduces the amount of nitrogen oxide and dust by 30% or more than the conventional burner, a separate exhaust gas reprocessing facility such as a nitrogen oxide reduction catalyst or an electrostatic precipitator is unnecessary or its capacity is reduced. It can reduce the installation cost and operation cost, and has an excellent effect such as preventing pollution.

Claims (1)

In the nitrogen oxide low production burner utilizing the two-stage combustion method and the exhaust gas recirculation method, the burner outer cylinder 3 and the flow dividing cylinder 6 having a length extending to the burner neck 8 and an enlarged radius at the end thereof are provided. And a swirl generator (2) and an injection nozzle (1) installed at an inner end of the burner outer cylinder (3).

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