CN112432169A

CN112432169A - Double-internal-circulation low-nitrogen combustor

Info

Publication number: CN112432169A
Application number: CN202011457370.XA
Authority: CN
Inventors: 刘永才; 陈令清; 刘刚
Original assignee: Shenzhen Jiayuntong Electronics Co Ltd
Current assignee: Shenzhen Jiayuntong Electronics Co Ltd
Priority date: 2020-12-11
Filing date: 2020-12-11
Publication date: 2021-03-02

Abstract

The invention discloses a double internal circulation low-nitrogen combustor, which comprises: the device comprises an air duct, a first fuel supply pipe, a second fuel supply pipe, an outer injection pipe, a fan and a flame stabilizing disc; the first fuel supply pipe is arranged in the air duct, and the front end of the first fuel supply pipe is provided with a plurality of inner branch air pipes for supplying fuel to the central flame; the second fuel supply pipe is arranged outside the air cylinder and used for injecting fuel to form a split flame; a mixing barrel is sleeved outside the front end of the air barrel, and a first flue gas backflow port is formed by a channel between the mixing barrel and the air barrel; the outer injection pipe is arranged in front of the nozzle and outside the mixing cylinder, and an inlet of the outer injection pipe forms a second flue gas backflow port; the first flue gas return port is positioned in front of the second flue gas return port. The invention comprehensively utilizes the central flame stabilizing technology and the FIR technology, realizes double-internal-circulation low-nitrogen combustion, can effectively reduce the emission of nitrogen oxides, and improves the thermal efficiency, safety and stability of combustion.

Description

Double-internal-circulation low-nitrogen combustor

Technical Field

The invention relates to the technical field of gas burners, in particular to a double-internal-circulation low-nitrogen burner.

Background

National environmental protection policy is becoming stricter and the requirement for boiler nitrogen oxide emission is becoming higher and higher. Most of the nitrogen reducing means adopted by the low-nitrogen combustion burners in the current market comprise an FGR (flue gas Recirculation) technology, a premixed combustion technology and the like, and have the inevitable defect while achieving the nitrogen reducing effect. For example, a burner using the FGR technology is prone to problems such as flue gas condensate corrosion and surge; the problems of low thermal efficiency and tempering risk caused by high oxygen content of flue gas easily occur by adopting a premixed combustion technology.

Disclosure of Invention

The invention aims to: the defects in the prior art are overcome, and the double-internal-circulation low-nitrogen combustor with high thermal efficiency, high safety and stable combustion is provided.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows.

A dual internal circulation low-nitrogen combustor comprising: the device comprises an air duct, a first fuel supply pipe, a second fuel supply pipe, an outer injection pipe, a fan and a flame stabilizing disc; the air duct is inserted into the mounting hole of the heating equipment, the front end of the air duct is exposed to the combustion chamber of the heating equipment and used for guiding combustion-supporting air to the combustion chamber, and the rear end of the air duct is connected with the fan; the first fuel supply pipe is arranged in the air duct, the front end of the first fuel supply pipe is provided with a plurality of inner branch pipes, and the tail ends of the inner branch pipes are provided with spray holes for supplying fuel to the central flame; the second fuel supply pipe is arranged outside the air duct, the front end of the second fuel supply pipe is provided with a plurality of outer branch pipes, and the tail ends of the outer branch pipes are provided with nozzles which are used for injecting fuel towards the direction of the combustion chamber to form divided flames; a flame stabilizing disc is arranged in the front end of the air duct, a channel between the air duct and the flame stabilizing disc is a central flame air distribution channel, and the central flame air distribution channel is used for supplying combustion-supporting air for central flame; a mixing barrel is sleeved outside the front end of the air barrel, and a first flue gas backflow port is formed by a channel between the mixing barrel and the air barrel; the outer injection pipe is arranged in front of the nozzle and positioned outside the mixing cylinder, and an inlet of the outer injection pipe close to the nozzle end forms a second flue gas backflow port; the first flue gas return opening is positioned in front of the second flue gas return opening; and a plurality of air distribution ports are circumferentially arranged on the wall of the air duct and are positioned behind the flame stabilizing disc, and the air distribution ports are used for supplying part of combustion-supporting air for the divided flame.

Furthermore, a partition plate is arranged outside the front end of the air duct and is positioned between the first flue gas backflow port and the second flue gas backflow port.

Further, the outer injection pipe is a straight pipe or a Laval pipe.

Further, the second flue gas recirculation port has a diameter-tapered inlet.

Further, the first fuel supply pipe comprises a main fuel gas pipe coaxially arranged with the air duct, the inner branch pipes are communicated with the downstream of the main fuel gas pipe, a central nozzle is arranged at the tail end of the main fuel gas pipe, and the jet direction of the jet holes at the tail end of the inner branch pipes faces the inner wall of the mixing drum.

Furthermore, the flame stabilizing disc is sleeved outside the central nozzle, and the inner branch pipes surround the outer side of the flame stabilizing disc.

Further, the second fuel supply pipe comprises a main supply pipe and a gas collecting bag connected with the main supply pipe, and a plurality of outer support pipes are connected to the gas collecting bag and arranged outside the front end of the air cylinder.

Furthermore, the front of each outer branch pipe is provided with one outer injection pipe, and the outer injection pipe and the outer branch pipe are positioned on the same straight line.

Furthermore, the volume ratio of the combustion-supporting air passing through the central flame air distribution channel to the whole combustion-supporting air is 80-95%, and the volume ratio of the fuel gas ejected through the nozzle of the second fuel supply pipe to the total fuel gas is 80-95%.

According to the technical scheme, the embodiment of the invention has the following advantages:

1. the first fuel supply pipe is arranged and matched with the flame stabilizing disc to form stable central flame, and the central flame stabilizing technology is utilized to ensure the stability of combustion and improve the safety of combustion;

2. the second fuel supply pipe is arranged and matched with the plurality of outer injection pipes to form divided flames, and the divided flame technology is utilized to reduce the temperature of the flames, thereby being beneficial to reducing the emission of nitrogen oxides;

3. the central flame and the divided flames are combusted in a way of deviating from the stoichiometric ratio, the combustion temperature is low, the heat efficiency is high, and the generation of nitrogen oxides is less;

4. the comprehensive utilization dual smoke internal circulation (FIR) technology through setting up first flue gas backward flow mouth and second flue gas backward flow mouth, makes central main flame all have the flue gas to participate in the burning with dividing apart flame, can effectual reduction nitrogen oxide's emission.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the embodiments and the drawings used in the description of the prior art, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.

FIG. 1 is a cross-sectional view of a dual internal circulation low NOx burner in one embodiment of the present invention;

FIG. 2 is a perspective view of a dual internal circulation low NOx burner in one embodiment of the present invention;

FIG. 3 is a schematic flow field diagram of a dual internal circulation low nitrogen combustor in an embodiment of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terms "first," "second," "third," and the like in the description and in the claims, and in the above-described drawings, are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

The following are detailed descriptions of the respective embodiments.

Referring to fig. 1 to 3, an embodiment of the present invention provides a dual internal circulation low-nitrogen burner, which is composed of an air duct 110, a first fuel supply pipe 120, a second fuel supply pipe 130, an outer injection pipe 140, a fan 150, a flame stabilizing disc 160, and the like.

The air duct 110 is inserted into a mounting hole of a heating device, such as a heating furnace body, and can be mounted and fixed by the mounting plate. The front end of the air duct 110 is exposed to a combustion chamber inside the heating apparatus for introducing combustion-supporting air, such as air, toward the combustion chamber. The rear end of the air duct 110 is located outside the heating apparatus and connected to the fan 150. The mixing barrel 112 is sleeved outside the front end of the air barrel 110.

And a first fuel supply pipe 120 disposed inside the air duct 110 for supplying fuel to the center flame. The first fuel supply pipe 120 may include a main fuel gas pipe coaxially arranged with the air duct 110 and a plurality of inner branch pipes 121 disposed at a front end thereof, a plurality of, for example, 6 inner branch pipes 121 may be connected to a downstream of the main fuel gas pipe and uniformly distributed circumferentially, a central nozzle 122 is disposed at a tail end of the main fuel gas pipe, and a nozzle hole is disposed at a tail end of the main fuel gas pipe 121, and a spraying direction of the nozzle hole faces an inner wall of the mixing duct 112.

The second fuel supply pipe 130 is disposed outside the air duct 110, and includes a main supply pipe and a gas collecting bag 131 connected to the main supply pipe, the front end of the gas collecting bag 131 is divided into a plurality of inner branch pipes 133, the plurality of inner branch pipes 133 are circumferentially arranged outside the front end of the air duct 110, a nozzle 132 is disposed at the end of the inner branch pipe 133, and the nozzle 132 injects fuel gas in the direction of the combustion chamber to form a split flame.

The burner of the present invention employs a central flame stabilization technique and is provided with a flame stabilization disk 160. The flame stabilizing disc is arranged inside the front end of the air duct 110 and sleeved outside the central nozzle 122. A plurality of the inner branch pipes 121 may surround the outer side of the flame stabilizing disk 160. An annular channel is formed between the air duct 110 and the flame stabilizing disc 160 to serve as a central flame air distribution channel 111 for supplying combustion-supporting air to the central flame.

The invention adopts FIR technology, which is provided with two smoke return ports. The air duct 110 and the mixing tube 112 sleeved outside the front end thereof form a first flue gas recirculation port 114. An outer injection pipe 140 is disposed in front of each nozzle 132, and the outer injection pipe 140 and the outer support pipe 133 may be located on the same straight line. An outer ejector tube 140 is located outside the mixing barrel 112, and an inlet of the outer ejector tube 140 near the nozzle 132 forms a second flue gas recirculation port 142. Wherein, for better realization of the double internal circulation, the first flue gas recirculation port 114 is located in front of the second flue gas recirculation port 142, i.e. the 1 st flue gas recirculation port 114 is deeper into the combustion chamber than the 2 nd flue gas recirculation port 142.

Furthermore, a plurality of air distribution ports 113 can be circumferentially arranged on the wall of the air duct 110 behind the flame stabilizing disc 160, a part of the combustion-supporting air can flow out of the air distribution ports 113, and the air distribution ports 113 are used for supplying a part of the combustion-supporting air for the divided flame.

Further, a partition plate 141 may be provided between the first and second flue

gas recirculation ports

114 and 142 outside the front end of the air duct 110.

Further, the outer injection pipe 140 may be a straight pipe, or may also be in a shape of a laval pipe, and at this time, the inlet of the first flue gas recirculation port 114 is a tapered inlet with a tapered diameter.

Next, the flow field and the nitrogen reduction principle of the combustor of the present invention will be explained.

The fan supplies combustion-supporting air into the air duct, as the downstream is provided with the flame stabilizing disc, most of the combustion-supporting air (the volume accounts for 80% -95%) flows through the central flame air distribution channel between the flame stabilizing disc and the air duct, as the flow area is reduced, the flow speed of the combustion-supporting air is increased and the static pressure is reduced, the flue gas in the combustion chamber can be pumped into the mixing drum through the first flue gas backflow port, and the flue gas and the combustion-supporting air are mixed and then combusted with the fuel (the volume accounts for 5% -15% of the total fuel amount) sprayed out through the inner branch pipe at the tail end of the first fuel supply pipe and the central nozzle to form central flame (namely main flame).

Because the static pressure of combustion-supporting air at the upstream of the flame stabilizing disc is increased due to the blocking of the flame stabilizing disc, a small part of combustion-supporting air (the volume accounts for 5-20%) flows out of an air distribution opening on the wall surface of the air duct, and the combustion-supporting air is provided for the divided flame.

High-pressure fuel gas (the volume accounts for 80-95% of the total fuel) is sprayed out through a nozzle of a gas path of the second fuel supply pipe, and simultaneously air flowing out through a gas distribution opening of the air duct and flue gas in the combustion chamber are sucked and enter the outer injection pipe through the second flue gas backflow opening to participate in combustion to form divided flame.

Wherein, the central flame has more wind and less gas, and is oxygen-enriched combustion; the flame is divided into a small amount of wind and a large amount of gas, and is in anoxic combustion; the central flame and the divided flames are combusted in a mode of deviating from a chemical equivalence ratio, the combustion temperature is low, nitrogen oxides are generated less, smoke participates in the combustion of the central main flame and the divided flames, and reducing atmosphere is formed, so that the generation of the nitrogen oxides is further reduced.

In addition, the gas sprayed out of the central nozzle of the first fuel supply pipe is mixed with combustion-supporting air and is close to the flame stabilizing disc to be combusted in a rotating mode, and a flame stabilizing area is formed.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to the related descriptions of other embodiments.

The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; those of ordinary skill in the art will understand that: the technical solutions described in the above embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A double internal circulation low-nitrogen burner is characterized in that,

the method comprises the following steps: the device comprises an air duct (110), a first fuel supply pipe (120), a second fuel supply pipe (130), an outer injection pipe (140), a fan (150) and a flame stabilizing disc (160);

the air duct (110) is inserted into a mounting hole of the heating equipment, the front end of the air duct (110) is exposed to a combustion chamber of the heating equipment and used for guiding combustion-supporting air to the combustion chamber, and the rear end of the air duct (110) is connected with the fan (150);

the first fuel supply pipe (120) is arranged inside the air duct (110), the front end of the first fuel supply pipe is provided with a plurality of inner branch pipes (121), and the tail ends of the inner branch pipes (121) are provided with spray holes for supplying fuel to the central flame;

the second fuel supply pipe (130) is arranged outside the air duct (110), a plurality of outer branch pipes (133) are arranged at the front end of the second fuel supply pipe, nozzles (132) are arranged at the tail ends of the outer branch pipes (133), and the nozzles (132) are used for injecting fuel towards the combustion chamber to form divided flames;

a flame stabilizing disc (160) is arranged in the front end of the air duct (110), a channel between the air duct (110) and the flame stabilizing disc (160) is a central flame air distribution channel (111), and the central flame air distribution channel (111) is used for supplying combustion-supporting air for central flame;

a mixing barrel (112) is sleeved outside the front end of the air barrel (110), and a first flue gas reflux opening (114) is formed by a channel between the mixing barrel (112) and the air barrel (110); the outer injection pipe (140) is arranged in front of the nozzle (132) and positioned outside the mixing barrel (112), and an inlet of the outer injection pipe (140) close to the nozzle (132) forms a second flue gas backflow port (142);

the first flue gas recirculation port (114) is located forward of the second flue gas recirculation port (142); the wall of the air duct (110) is circumferentially provided with a plurality of air distribution ports (113) which are positioned behind the flame stabilizing disc (160), and the air distribution ports (113) are used for supplying part of combustion-supporting air for the divided flame.

2. The dual internal circulation low NOx burner of claim 1,

a partition plate (141) is arranged outside the front end of the air duct (110), and the partition plate (141) is located between the first flue gas backflow port (114) and the second flue gas backflow port (142).

3. The dual internal circulation low NOx burner of claim 1,

the outer injection pipe (140) is a straight pipe or a Laval pipe.

4. The dual internal circulation low NOx burner of claim 1,

the second flue gas recirculation port (142) has a tapered diameter inlet.

5. The dual internal circulation low NOx burner of claim 1,

the first fuel supply pipe (120) comprises a gas main pipe coaxially arranged with the air duct (110), a plurality of inner branch pipes (121) are communicated with the downstream of the gas main pipe, a central nozzle (122) is arranged at the tail end of the gas main pipe, and the spraying direction of the spray holes at the tail ends of the inner branch pipes (121) faces to the inner wall of the mixing drum (112).

6. The dual internal circulation low NOx burner of claim 1,

the flame stabilizing disc (160) is sleeved outside the central nozzle (122), and the inner branch pipes (121) surround the outer side of the flame stabilizing disc (160).

7. The dual internal circulation low NOx burner of claim 1,

the second fuel supply pipe (130) comprises a main supply pipe and a gas collecting bag (131) connected with the main supply pipe, and a plurality of outer branch pipes (133) are connected to the gas collecting bag (131) and arranged outside the front end of the air duct (110).

8. The dual internal circulation low NOx burner of claim 1,

the front of each outer branch pipe (133) is provided with one outer injection pipe (140), and the outer injection pipe (140) and the outer branch pipe (133) are positioned on the same straight line.

9. The dual internal circulation low NOx burner of claim 1,

the volume ratio of the combustion-supporting air passing through the central flame air distribution channel (111) to the whole combustion-supporting air is 80-95%, and the volume ratio of the fuel gas ejected through the nozzle of the second fuel supply pipe to the total fuel gas is 80-95%.