CN207539904U - Ultralow nitrogen gas burner - Google Patents

Abstract

The utility model is related to a kind of ultralow nitrogen gas burners, include the air duct of level-one combustion gas header, second gas burning collection ring, furnace body, igniter and both ends open, and the furnace wall of outlet across the furnace body in air duct enters burner hearth；Air duct includes at least center air duct, an air duct and the secondary air duct being arranged successively from inside to outside, and level-one combustion gas header and second gas burning collection ring are all connected with combustion gas main pipe；Wherein, level-one combustion gas header connection central lance and several level-one gas guns, central lance and level-one gas gun are stretched into the air duct of center；Several second gas burning spray guns are uniformly connected on second gas burning collection ring, second gas burning spray gun is stretched into secondary air duct；In the centrally disposed spray gun of igniter and firing tip is extend out to outside the port of export of central lance.The utility model realizes the circumferential classification of fuel, improves air/gas mixing situation, burning is balanced, reduces NOx generations using double headers and nest of tubes formula method of supplying.

Description

Ultra-low nitrogen gas burner

technical field

The utility model belongs to the field of burners, in particular to an ultra-low nitrogen gas burner.

Background technique

With the rapid development of the economy, the consumption of energy is increasing rapidly, and the pollution caused by fuel combustion is becoming more and more serious. Urban energy has begun to move towards the era of natural gas, especially the implementation of the "West-to-East Gas Transmission" project, which marks the arrival of the era of natural gas for urban gas in China. After comparing the emissions of oil, coal, and natural gas in the combustion process, it is found that the gas emissions of natural gas are much less than those of other fuels, and only the emission of NOx is on the same order of magnitude. With the rapid development of the natural gas industry, the pollution of nitrogen oxides produced after the combustion of natural gas cannot be ignored. Therefore, the development of ultra-low nitrogen gas burners is of great significance to China's environmental protection.

Commonly used low-nitrogen combustion technologies include staged combustion, premixed combustion, flue gas recirculation, porous media combustion, flameless combustion, etc. Among them, full premixed combustion, porous media combustion, and flameless combustion are not suitable for high-power burners. Combustion, partial premixed combustion, flue gas recirculation and other technologies have become the direction of high-power burners.

Since the combustion temperature reaches the highest when the equivalence ratio is 1, the staged combustion technology realizes lean or rich combustion, and its combustion temperature is lower than the combustion temperature when the equivalence ratio is 1, so the temperature field distribution in the furnace can be reasonably distributed , to avoid local high temperature and achieve the effect of reducing NOx generation, but how to achieve good air/gas classification is a difficult point.

The flue gas recirculation reduces the combustion temperature by adding the combustion products and intermediates of the flue gas into the combustion area. At the same time, the added flue gas reduces the partial pressure of oxygen, which can weaken the generation of thermal NOx. Studies have shown that external flue gas recirculation can reduce NOx formation by 70%. The problem with flue gas recirculation is that the external flue gas recirculation occupies a large space and requires high investment, while the internal flue gas recirculation is less effective in reducing nitrogen oxide emissions.

Contents of the invention

The purpose of the utility model is to overcome the problems existing in the prior art, and provide an ultra-low nitrogen gas burner, which can realize balanced combustion and reduce NOx generation.

In order to achieve the above object, the utility model adopts the following technical solutions:

It includes the first-level gas header, the second-level gas collection ring, the furnace body, the igniter and the air duct with openings at both ends. The outlet of the air duct passes through the furnace wall of the furnace body and enters the furnace; The central air duct, the primary air duct and the secondary air duct, the primary gas header and the secondary gas collecting ring are all connected to the gas main pipe;

Among them, the primary gas header is connected to the central spray gun and several primary gas spray guns, and both the central spray gun and the primary gas spray gun extend into the central air duct; the secondary gas collection ring is evenly connected to several secondary gas spray guns, and the secondary gas The spray guns all extend into the secondary air duct; the igniter is arranged in the central spray gun and the ignition end extends out of the outlet end of the central spray gun.

Further, the central air duct, the primary air duct and the secondary air duct all include a connected horizontal section air duct and a volute section air duct, wherein the axis of the horizontal section air duct is perpendicular to the plane where the volute section air duct is located; The first-stage gas header, the second-stage gas collector ring, the central spray gun and the air duct in the horizontal section are all arranged concentrically.

Further, the outlet end of the central spray gun protrudes out of the central air duct, and a flame stabilization plate is arranged outside the outlet end of the central spray gun.

Further, the first-stage gas spray guns are evenly distributed around the center spray gun, the outlet end of the first-stage gas spray gun is located in the central air duct, and a partial premixing section is formed between the outlet end of the first-stage gas spray gun and the outlet end of the central air duct.

Further, the outlet of the primary gas spray gun is provided with a V-shaped nozzle, and two spray holes are symmetrically opened on the side wall of the V-shaped nozzle, one of which faces the central spray gun, and the other spray hole faces the side wall of the central air duct.

Further, the outlet of the secondary gas spray gun is provided with a detachable trapezoidal nozzle, and the trapezoidal nozzle includes an axial nozzle, an inner nozzle facing the igniter and an outer nozzle facing the furnace wall.

Further, along the airflow direction, the position of the nozzle of the secondary gas spray gun is behind the outlet of the central spray gun.

Further, an inclined platform is arranged on the inner side of the side wall close to the central air duct at the outlet end of the secondary air duct to form a tapered nozzle along the airflow direction; The wind slit, the end of the side wall where the air inlet slit is opened is connected to the deflector, and the deflector is arranged inclined toward the furnace wall.

Further, on the outside of the secondary air duct, a slope is set on the furnace wall to form a gradually expanding bell mouth; an asbestos gasket is set between the furnace wall and the secondary air duct.

Furthermore, the inlet ends of the air ducts are all provided with air regulating plates for adjusting the air intake volume.

Compared with the prior art, the utility model has the following beneficial technical effects:

The utility model adopts the first-level gas header and the second-level gas collection ring connected with the gas main pipe, the first-level gas header is connected with the central spray gun and the first-level gas spray gun, and the second-level gas collection ring is connected with the second-level gas spray gun to form a double The header and pipe group supply mode, the gas is sent from the gas main pipe to the first-level gas header and the second-level gas collection ring, and then distributed to each gas spray gun tube, and mixed with air from several gas spray gun tubes to realize the fuel consumption. Circumferential grading, by coordinating with the central air duct, primary air duct and secondary air duct, the utility model can supply air and gas required for combustion in stages, improves the mixing of air/gas, and achieves the purpose of combustion balance. Reasonably distribute the temperature field distribution in the furnace to avoid local high temperature and achieve the effect of reducing NOx generation.

Furthermore, the utility model sets the volute segment air duct to make the air flow in the volute to generate a swirl flow, which is conducive to the formation of a recirculation zone, achieving flame stability, and at the same time can improve the mixing with fuel and improve combustion efficiency.

Further, the utility model sets up a partial premixing section, and the air/gas can be mixed in the partial premixing section, so as to achieve the purpose of partial premixing.

Further, the utility model adopts a V-shaped nozzle, the inner nozzle cooperates with the central spray gun to form the main flame, the outer nozzle and the primary air blown from the primary air duct support the combustion on the periphery, and the central flue gas reflow area is formed between the inner and outer nozzles, so that the high temperature and low speed Combustion products and intermediates preheat and dilute unreacted air and fuel, which can effectively enhance combustion and stabilize the flame. At the same time, the flue gas backflow makes the temperature distribution in the furnace more uniform, reduces the maximum combustion temperature, narrows the high temperature zone, and inhibits the formation of thermal NOx

Further, the utility model can replace different models according to different requirements by setting detachable trapezoidal nozzles, and determine the number of openings; and the internal nozzles of the trapezoidal nozzles are sprayed to the central flame for combustion-supporting purposes, and the external nozzles are sprayed to The furnace wall cooperates with the furnace wall to form the backflow of flue gas corners.

Furthermore, the utility model arranges the nozzle of the secondary gas spray gun on the rear side of the outlet of the central spray gun, which can not only realize the staged combustion of the fuel in the axial direction, but also prolong the contact time between the secondary fuel and the central flame, and to a certain extent Reduces fast NOx formation.

Further, the utility model forms a tapered nozzle to make it an ejector, where the speed of the secondary air blown out from the secondary air duct is accelerated to form a negative pressure area; and the air inlet slit and the deflector are set Driven by the power of the negative pressure area formed by the ejector, the backflow flue gas at the corner flows into the secondary air outlet along the deflector through the air inlet gap and mixes with it to achieve the effect of flue gas external circulation and realize lean Oxygen controls the combustion temperature and reduces the amount of thermal NOx generated; at the same time, the flue gas circulation of the utility model is completed inside the furnace wall without occupying extra space.

Furthermore, the utility model enlarges the corner recirculation area by setting a gradually expanding bell mouth, and at the same time diverts the circulating flue gas into the negative pressure area.

Furthermore, the utility model can adjust the air intake volume of each air duct by setting the air regulating plate.

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a structural schematic diagram of the primary gas header of the utility model.

Fig. 3 is a schematic diagram of the structure of the secondary gas collection ring of the present invention.

Fig. 4 is a structural schematic diagram of a first-stage gas spray gun of the present invention.

Fig. 5 is a schematic structural diagram of a secondary gas spray gun of the present invention.

Among them: 1-first-level gas header; 2-secondary gas collection ring; 3-air duct; 4-first-level gas spray gun; 5-V-shaped nozzle; 6-partial premixing section; -central spray gun; 9-inclined platform; 10-air inlet gap; 11-deflector; 12-furnace wall; 13-trapezoid nozzle; 14-central air duct; 15-primary air duct; ; 17-secondary gas spray gun; 18-air regulating plate; 19-asbestos gasket; 20-igniter.

Detailed ways

Below in conjunction with accompanying drawing, the utility model is described in further detail.

Referring to Fig. 1 to Fig. 5, the utility model comprises a primary gas header 1, a secondary gas collecting ring 2, a furnace body, an igniter 20 and an air duct 3 with openings at both ends, and the outlet of the air duct 3 passes through the furnace body The furnace wall 12 enters the furnace; the air duct 3 at least includes a central air duct 14, a primary air duct 15 and a secondary air duct 16 which are set sequentially from the inside to the outside, and the primary gas header 1 and the secondary gas collector 2 are connected to the gas mother tube.

Wherein, with reference to Fig. 2, the primary gas header 1 is connected to the central spray gun 8 and several primary gas spray guns 4, the primary gas spray guns 4 are evenly distributed around the central spray gun 8, and the central spray gun 8 and the primary gas spray guns 4 are all extended. into the central air duct 14; with reference to Fig. 3, several secondary gas spray guns 17 are evenly connected on the secondary gas collection ring 2, and the secondary gas spray guns 17 all extend into the secondary air duct 16; the igniter 20 is arranged on the central spray gun 8 and the ignition end stretches out of the outlet end of the central spray gun 8. The central gas is delivered through the primary gas spray gun 4 and the central spray gun 8, and the secondary gas is delivered through the secondary gas spray gun 17.

The central air duct 14, the primary air duct 15 and the secondary air duct 16 all include a connected horizontal section air duct and a volute section air duct, wherein the axis of the horizontal section air duct is perpendicular to the plane where the volute section air duct is located; The primary gas header 1, the secondary gas collecting ring 2, the central spray gun 8 and the horizontal section air duct are all arranged concentrically.

The outlet end of the central spray gun 8 protrudes out of the central air duct 14 , and the flame stabilization plate 7 is arranged outside the outlet end of the central spray gun 8 . The outlet end of the first-stage gas spray gun 4 is located in the central air duct 14 , and a part of the premixing section 6 is formed between the outlet end of the first-stage gas spray gun 4 and the outlet end of the central air duct 14 .

Referring to Fig. 4, the outlet of the primary gas spray gun 4 is provided with a V-shaped nozzle 5, the stereogram of the V-shaped nozzle 5 is a cone, and the plane projection is V-shaped. Two spray holes are respectively opened on two intersecting lines of the type nozzle 5 fans, and the two spray holes are distributed symmetrically, one towards the central spray gun 8, and the other towards the side wall of the central air duct 14. Referring to Fig. 5, the outlet of the secondary gas spray gun 17 is provided with a detachable trapezoidal nozzle 13, and the connection methods include: threaded connection, key connection, pin connection and other detachable mechanical connection methods; The internal spout of igniter 20 and the external spout toward furnace wall 12, internal spout and external spout opening mode are identical with the opening mode of spray hole on the V-shaped nozzle 5. Along the airflow direction, the nozzle position of the secondary gas spray gun 17 is on the rear side of the outlet of the central spray gun 8 .

The outlet end of the secondary air duct 16 is provided with an inclined platform 9 on the inner side of the side wall close to the central air duct 14 to form a tapering nozzle along the air flow direction; An air inlet slit 10 is provided, and the end of the side wall where the air inlet slit 10 is opened is connected to a deflector 11 , and the deflector 11 is arranged obliquely toward the furnace wall 12 .

On the outside of the secondary air duct 16, a slope is provided on the furnace wall 12 to form a gradually expanding bell mouth; an asbestos gasket 19 is provided between the furnace wall 12 and the secondary air duct 16.

The inlet ends of the air ducts 3 are all provided with air regulating plates 18 for adjusting the air intake volume, so that the air intake volume of each air duct can be adjusted.

Main work process and principle of the utility model are:

The burner of the utility model adopts the gas double header supply mode, and the two-stage gas pipelines are pipe group burners, and a first-stage gas header 1 is provided for the central gas; a second-stage gas collection ring 2 is provided for the secondary gas; natural gas The main pipe is sent into the primary gas header 1 and the secondary gas collecting ring 2, and then distributed to the central spray gun 8, each primary gas spray gun 4 and secondary gas spray gun 17. The gas flows out from several small tubes, and the air flows out from the central air duct 14 or the secondary air duct 16 at a relatively high speed and mixes with the gas, which improves the air/gas mixing situation, and the primary air blown out of the primary air duct 15 plays a combustion-supporting role , to achieve the purpose of combustion balance.

The central spray gun 8 of the central gas pipeline extends out of the central air duct 14, and the outlet of the first-stage gas spray gun 4 is inside the central air duct 14, and the air/gas can be mixed in the partial premixing section 6, thereby achieving the purpose of partial premixing. The outlet of the primary gas spray gun 4 of the center gas adopts a V-shaped nozzle 5, and the inner nozzle cooperates with the central spray gun 8 to form the main flame, and the primary air blown from the outer nozzle and the primary air duct 15 supports combustion on the periphery, and a central smoke return area is formed between the inner and outer nozzles. Therefore, the high-temperature and low-speed combustion products and intermediates can preheat and dilute the unreacted air and fuel, which can effectively enhance combustion and stabilize the flame. At the same time, the backflow of flue gas makes the temperature distribution in the furnace more uniform, reduces the maximum combustion temperature, narrows the high temperature zone, and inhibits the formation of thermal NOx.

The position of the nozzle of the secondary gas spray gun 17 is at the rear of the central air, which can not only realize the axial staged combustion of the fuel, but also prolong the contact time between the secondary fuel and the central flame, which can reduce the formation of rapid NOx to a certain extent. The outlet of the secondary gas spray gun 17 adopts a trapezoidal nozzle 13, and the trapezoidal nozzle 13 is detachable, so different models can be replaced according to different requirements, and the number of openings can be determined. Spray toward the furnace wall 12, cooperate with the furnace wall 12 to form the backflow of flue gas corners.

The outlet of the secondary air duct 16 is designed as a tapered nozzle, making it an ejector. The speed of the secondary air blown out of the secondary air duct 16 is accelerated there, forming a negative pressure area, and the entrained circulating smoke enters the secondary Wind, so as to achieve the effect of external circulation of flue gas, achieve oxygen-lean control of combustion temperature, and reduce thermal NOx generation. A deflector 11 and an air inlet slit 10 are arranged at the outlet of the secondary air duct 16. Driven by the power of the negative pressure zone formed by the ejector, the backflow flue gas flows along the deflector 11 and passes through the air inlet slit 10. Flow into the secondary air outlet and mix with it.

At the outlet of the secondary air, the furnace wall 12 is opened into the form of a bell mouth, thereby increasing the recirculation area at the corners, and at the same time diverting the circulating flue gas into the negative pressure area.

The utility model is concentrically arranged with a central gas pipe group, a central air duct 14, a primary air duct 15, a secondary air duct 16, and a secondary gas pipeline from the inside to the outside. Ring, the outlet of the primary gas pipeline is provided with a V-shaped burner, the outlet of the secondary gas pipeline is provided with a trapezoidal burner, and the outlet of the secondary air duct 16 is provided with a tapered nozzle to form an ejector, and the outlet of the secondary air duct 16 is connected to the A deflector 11 and an air inlet slit 10 are arranged between the trapezoidal burners. The utility model adopts air/gas partial premixing, staged combustion, combined with flue gas recirculation, reduces thermal NOx and rapid NOx generation, and achieves the purpose of ultra-low nitrogen oxide emission. The utility model simplifies the structure, improves the discharge level of nitrogen oxides, and can realize ultra-low nitrogen discharge, which is of great significance for energy saving and emission reduction, and specifically has the following advantages:

(1) Staged combustion: There are central spray gun 8, primary gas spray gun 4, central air duct 14, primary air duct 15, secondary air duct 16 and secondary gas spray gun 17 arranged concentrically from the inside to the outside in order to supply the combustion needs in stages. Specifically, the volute air duct 3 structure is adopted, and it is divided into a central air duct 14, a primary air duct 15 and a secondary air duct 16 from inside to outside. The nozzles of the secondary gas spray gun 17 are located at the rear of the central air, which can not only prolong the contact time between the secondary fuel and the central flame, reduce the formation of rapid NOx to a certain extent, but also realize the axial staged combustion of the fuel. The gas adopts double headers and pipe group supply mode. There is a first-level gas header 1 for the central gas, and a second-level gas header 2 for the secondary gas. Natural gas is sent from the main pipe to the first-level gas header 1 and the second-level The gas collection ring 2 is then distributed to each gas spray gun tube, and the gas flows out from several small tubes to mix with the air, realizing the circumferential classification of the fuel. The primary and secondary gas pipelines respectively use V-shaped nozzles 5 and trapezoidal nozzles 13 to realize radial classification of fuel.

(2) Balanced combustion: the outlet of the first-stage gas spray gun 4 is inside the outlet of the central air duct, and the air/gas can be partially premixed in the partial premix section 6 between the two outlets, so as to improve the air/gas mixing situation and achieve The purpose of combustion balance. The burner adopts gas double headers and tube group supply mode, which improves the air/gas mixing.

(3) Central flue gas backflow: the outlet of the central gas pipeline adopts a V-shaped nozzle 5, the inner nozzle cooperates with the central spray gun 8 to form the main flame, the outer nozzle and the primary air are combustion-supporting at the periphery, and the central flue gas backflow area is formed between the inner and outer nozzles, thereby The high-temperature and low-speed combustion products and intermediates can preheat and dilute the unreacted air and fuel, which can effectively enhance combustion and stabilize the flame. At the same time, the backflow of flue gas makes the temperature distribution in the furnace more uniform, reduces the maximum combustion temperature, narrows the high temperature zone, and inhibits the formation of thermal NOx.

(4) Flue gas recirculation: the outlet of the secondary gas spray gun 17 adopts a trapezoidal nozzle 13, the inner nozzle is sprayed to the central flame for the purpose of combustion, and the outer nozzle is sprayed to the furnace wall 12, which cooperates with the furnace wall 12 to form a corner backflow of the flue gas Area. At the same time, the outlet of the secondary air duct 16 is designed as a tapered nozzle, making it an ejector, where the secondary wind speed is accelerated to form a negative pressure zone, and the circulating smoke in the cigarette smoke corner recirculation zone is guided The flow plate 11 flows into the secondary air outlet through the air inlet slit 10 and mixes with it, so as to achieve the effect of flue gas external circulation in the way of flue gas internal circulation, realize oxygen-deficient control of combustion temperature, and reduce thermal NOx generation .

Claims (10)

1. a kind of ultralow nitrogen gas burner, it is characterised in that：Including level-one combustion gas header (1), second gas burning collection ring (2), stove The air duct (3) of body, igniter (20) and both ends open, the outlet of air duct (3) is across the furnace wall (12) of furnace body into burner hearth；Air duct (3) including at least the center air duct (14) being arranged successively from inside to outside, an air duct (15) and secondary air duct (16), level-one combustion gas Header (1) and second gas burning collection ring (2) are all connected with combustion gas main pipe；

Wherein, level-one combustion gas header (1) connection central lance (8) and several level-one gas guns (4), central lance (8) and Level-one gas gun (4) is stretched into center air duct (14)；The spray of several second gas burnings is uniformly connected on second gas burning collection ring (2) Rifle (17), second gas burning spray gun (17) are stretched into secondary air duct (16)；In igniter (20) centrally disposed spray gun (8) and point Fire end is extend out to outside the port of export of central lance (8).

2. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：Center air duct (14), First air Road (15) includes the horizontal segment air duct and the spiral case section air duct that are connected with secondary air duct (16), wherein, the axis in horizontal segment air duct Line perpendicular to spiral case section air duct where plane；Level-one combustion gas header (1), second gas burning collection ring (2), central lance (8) and water Flat section air duct is arranged concentrically.

3. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：The port of export of central lance (8) It extend out to center air duct (14) outside, and arrangement stable flame pan (7) on the outside of the port of export of central lance (8).

4. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：Level-one gas gun (4) is uniform It is centrally located the surrounding of spray gun (8)；The port of export of level-one gas gun (4) is located in center air duct (14), level-one gas injection It is formed partly-premixed section (6) between the port of export of rifle (4) and the port of export of center air duct (14).

5. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：Level-one gas gun (4) go out Mouthful V-type nozzle (5) is provided with, is symmetrically opened up on the side wall of V-type nozzle (5) there are two spray orifice, one of spray orifice is towards center Spray gun (8), another spray orifice is towards the side wall of center air duct (14).

6. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：Second gas burning spray gun (17) go out Mouth is provided with the ladder type nozzle (13) that can be dismantled, and ladder type nozzle (13) includes axial spout, the inside towards igniter (20) Spout and the external spout towards furnace wall (12).

7. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：Along airflow direction, second gas burning The nozzle exit area of spray gun (17) exports rear side in central lance (8).

8. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：The port of export of secondary air duct (16) Sloping platform (9) is provided on the inside sidewalls face in center air duct (14), forms the tapered spout along airflow direction；Secondary air duct (16) the port of export opens up air inlet gap (10) on the side wall of furnace wall (12), and the side wall end for opening up air inlet gap (10) connects Deflector (11) is connect, deflector (11) is obliquely installed towards furnace wall (12).

9. a kind of ultralow nitrogen gas burner according to claim 8, it is characterised in that：On the outside of secondary air duct (16), Slope on furnace wall (12) is set, forms gradual-enlargement type horn mouth；Asbestos washer is set between furnace wall (12) and secondary air duct (16) (19)。

10. a kind of ultralow nitrogen gas burner according to claim 1, it is characterised in that：The arrival end in air duct (3) is all provided with It is equipped with the air regulating board (18) for adjusting intake.