DE202022107002U1 - Burner with low NOx emission - Google Patents

Abstract

A low-NOx burner nozzle characterized by comprising an air outer case (1), an air inner case (2), and a fuel gas duct (3) which are coaxially jacketed from outside to inside in succession, the front open end of the air outer case (1) is flush with the front open end of the air inner case (2) to form a flame ejection port (21); the front closed end of the fuel gas pipe (3) is behind the flame ejection opening (21) and is spaced from the flame ejection opening (21); the area between the air outer case (1) and the air inner case (2) is an outer air duct (14); the area between the air inner casing (2) and the fuel gas pipe (3) is an internal air duct (23); a total air inlet (131) is provided at the rear of the air outer case (1); the air inner casing (2) is provided with a primary air inlet (24) and a secondary air inlet (25) located in front of the primary air inlet (24); the extension direction line of the secondary air inlet (25) perpendicular to the axis of the burner nozzle is in a different plane; and the front end surface of the air outer casing (1) is further provided with a tertiary air inlet (111).

Description

technical field

The present disclosure relates to the technical field of combustors, and more particularly to a low NOx combustor nozzle.

Technical background

The term "burner nozzle" means a device that mixes a fuel with air and ignites it to produce a stable flame. The burner nozzle can also be referred to as a burner and forms the main body part of a combustion device. Burner nozzles are widely applied to metallurgical field, power generation field, petrochemical field, and building material field, and are used particularly in heating and heat treatment equipment in nonferrous metal industry and iron and steel industry. As a core component for heating furnaces and heat treatment furnaces, the burner nozzle directly affects technical indicators of the equipment, such as production capacity, thermal efficiency, energy consumption, emission and the like.

Numerous studies show that staged combustion technology of air has a good effect on inhibiting the formation of thermal nitrogen oxides, and in actual burners, the processing and operations are facilitated, the connection of an external facility is unnecessary, and effective control over the total cost of a heating stove is made possible. Therefore, in a conventional burner nozzle, the staged combustion technique of air is used, in which the air necessary for combustion is introduced into and participates in the combustion process twice or more, forming at least a two-stage combustion process. A conventional burner nozzle consists primarily of a fuel gas inlet, stepped air inlets, an electronic spark plug, a flame stabilizing disc, and similar components. Here, primary air inlets are evenly distributed on the inner air casing of the burner nozzle and are located in the circumferential direction of the part of the air rear casing of the burner nozzle and are perpendicular to the axis of the burner nozzle in the same plane; secondary air inlets are evenly distributed on the inner air casing of the burner nozzle and are located in the circumferential direction of the part of the air front casing of the burner nozzle and are perpendicular to the axis of the burner nozzle in the same plane; and tertiary air inlets are evenly distributed around a flame ejection opening on the front end surface of the air front casing of the burner nozzle and form an angle of 20° with the plane of the axis of the burner nozzle. In the initial combustion, primary air enters the burner nozzle first and is mixed together with fuel gas and ignited, then secondary air, tertiary air, etc. are introduced into the initial combustion area.

However, in conventional burner nozzles, such a method of introducing air is used that the air intake port is perpendicular to the axial direction of the burner nozzle, which allows air and fuel gas to be immediately mixed for burning, especially secondary air is immediately rapidly sprayed into the initial combustion zone, so that the Intensity of combustion is increased, and the temperature and speed of combustion flames are increased, whereby the air-fuel ratio (the ratio of air to fuel gas) at that time is close to the theoretical air-fuel ratio of combustion reaction (the mass ratio of substances under standard conditions is converted to the volume ratio at normal temperature and pressure), while an air-fuel ratio close to the theoretical air-fuel ratio leads to the occurrence of local high-temperature. Then, under the oxidizing effect of tertiary air, the flame further increases the combustion intensity, and when the air-fuel ratio is too high, a large air inlet angle of tertiary air leads to the poor temperature lowering effect of flames. For this reason, the combustion temperature has reached the thermal nitrogen monoxide formation temperature at this time, resulting in the continuous increase in the concentration of thermal nitrogen monoxide (nitrogen oxide produced from the oxidation of nitrogen in a high-temperature environment) in the combustion product, so that the phenomenon of high-concentration aggregation occurs of nitrogen monoxide occurs, indexes of environmental protection engineering of burner nozzles and furnace bodies are deteriorated, and air pollution is aggravated.

subject of revelation

(I) The technical problem to be solved

To solve the above problems in the prior art, the present disclosure provides a low-NOx burner nozzle to solve the technical problem that the concentration of nitrogen monoxide in the combustion product of a staged combustion burner nozzle is too high, resulting in exceeding the standards of pollutant emissions.

(II) Technical Solution

• Die vorliegende Offenbarung stellt eine NOx-emissionsarme Brennerdüse bereit, umfassend: ein Luftaußengehäuse, ein Luftinnengehäuse, und eine Brenngasrohrleitung, die von außen nach innen nacheinander koaxial ummantelt sind, wobei das vordere offene Ende des Luftaußengehäuses bündig mit dem vorderen offenen Ende des Luftinnengehäuses ist, um eine Flammenausstoßöffnung auszubilden; sich das vordere geschlossene Ende der Brenngasrohrleitung hinter der Flammenausstoßöffnung befindet und von der Flammenausstoßöffnung beabstandet ist; der Bereich zwischen dem Luftaußengehäuse und dem Luftinnengehäuse ein äußerer Luftkanal ist; der Bereich zwischen dem Luftinnengehäuse und der Brenngasrohrleitung ein innerer Luftkanal ist; ein Gesamtlufteinlass am Hinterteil des Luftaußengehäuses vorgesehen ist; das Luftinnengehäuse mit einem primären Lufteinlass und einem sekundären Lufteinlass, der sich vor dem primären Lufteinlass befindet, versehen ist; die Erstreckungsrichtungslinie des sekundären Lufteinlasses in einer Ebene senkrecht zur Achse der Brennerdüse in einer verschiedenen Ebene steht; und die vordere Endfläche des Luftaußengehäuses noch mit einem tertiären Lufteinlass versehen ist.

In order to achieve the above object, a main technical solution applied in the present disclosure includes:

• The present disclosure provides a low-NOx combustor nozzle, comprising: an outer air casing, an inner air casing, and a fuel gas duct lined coaxially in sequence from outside to inside, the front open end of the outer air casing being flush with the front open end of the inner air casing, to form a flame ejection port; the front closed end of the fuel gas pipe is located behind the flame ejection opening and is spaced from the flame ejection opening; the area between the air outer case and the air inner case is an outer air duct; the area between the air inner case and the fuel gas duct is an internal air duct; a total air inlet is provided at the rear of the air outer case; the air inner case is provided with a primary air inlet and a secondary air inlet located in front of the primary air inlet; the extending direction line of the secondary air inlet is in a plane perpendicular to the axis of the burner nozzle in a different plane; and the front end surface of the air outer case is further provided with a tertiary air inlet.

Further, at least one circle of the tertiary air inlets is provided around the flame ejection port, the extending direction lines of all the tertiary air inlets intersect at a point in front of the burner nozzle, and the directions of all the tertiary air inlets form an angle of 10° with the axis of the burner nozzle. 15°.

Further, the rear end face of the air outer case communicates with a rear cover, the rear cover communicates with a fuel gas case, a fuel gas inlet passage is provided in the fuel gas case, and the fuel gas inlet passage communicates with the fuel gas piping; and a circle of fuel gas nozzles is provided in the circumferential direction of the front closed end of the fuel gas pipeline.

Also included is a flame stabilizing disk located within the air liner; the flame stabilizing disc is a disc-shaped structure with a hollow protrusion in the middle, the inner space of the hollow protrusion coincides with the outer contour of the front closed end of the fuel gas pipeline, the outer diameter of the flame stabilizing disc is equal to the inner diameter of the air inner case, a circle of first through holes is in the Circumferential direction of the hollow protrusion provided, the edge of the flame stabilizing disk is a serrated structure, each tooth of the serrated structure is arranged to form an inclination angle of 45° with the plane of the disk-shaped structure, and the distance between each adjacent teeth forms an air circulation channel; and when the flame stabilizing disc cooperates with the front closed end of the fuel gas pipeline, the plane of the disc-shaped structure is perpendicular to the axis of the burner nozzle, and the first through holes are arranged in one-to-one correspondence with the fuel gas nozzles.

Further, an electronic spark plug is still included, the electronic spark plug includes an electronic spark plug housing and an inner core electronic spark plug, the electronic spark plug housing is coaxially encased outside the inner core electronic spark plug, and the inner core electronic spark plug is longer than the electronic spark plug housing; a second through hole perpendicular to the fuel gas inlet port is provided at the bottom of the fuel gas inlet port in the fuel gas casing, the outer wall of the fuel gas piping is provided with a tubular structure parallel to the fuel gas piping, the flame stabilizing disk is provided with a circular hole, the axes of the second through hole, the tubular structure, and the circular hole are collinear, and the diameters of the second through hole, the tubular structure, and the circular hole are matched to the outer diameter of the electronic spark plug shell; and the electronic spark plug housing is continuously arranged in the second through hole, in the tubular structure, and in the circular hole so that it is fixed in the burner nozzle, the area between the head of the electronic spark plug and the flame ejection port forms an initial combustion zone, and the Electronic spark plug tail stays outside of fuel gas housing.

Further, a sealing jig is provided at the rear open end of the air inner casing in the inner air duct, the rear face plane of the sealing jig is in contact with the fuel gas casing, and the rear end of the sealing jig is flanged.

Furthermore, a buffer rubber is provided between the flange and the air inner case.

Further, two fixing pins are provided on the outer wall of the rear open end of the air inner case so as to be symmetrical with the axis of the burner nozzle as the center, and two positioning grooves are provided on the inner wall of the rear open end of the air outer case so as to be aligned with the axis of the burner nozzle Burner nozzle are symmetrical as the center, with the two locating pins cooperating with the two positioning grooves.

Furthermore, the tail of the electronic spark plug communicates with an energizing device.

Furthermore, the air outer housing comprises an air front housing, an air center housing, and an air rear housing, the air center housing and the air rear housing being in detachable connection with one another.

(III) Beneficial Effects

• Bei der in dieser Offenbarung bereitgestellten NOx-emissionsarme Brennerdüse wird eine Methode von gestufter Verbrennung in Kombination mit turbulenter Verbrennung angewendet, wobei die Richtung des sekundären Lufteinlasses von herkömmlicher Rechtwinkligkeit zu der Achse der Brennerdüse in die Rechtwinkligkeit zu der Achse der Brennerdüse in einer verschiedenen Ebene umgewandelt ist. Die Umwandlung der Richtung des sekundären Lufteinlasses ermöglicht die Erzeugung einer turbulenten Strömung wegen der Luftumdrehung (keine zusätzliche Anlage ist erforderlich), und die erzeugte turbulente Strömung kann die Vermischung mit Flammen verlangsamen, die Verbrennungsintensität langsam erhöhen und die Flammen zum Fernhalten von der anfänglichen Verbrennungszone kontrollieren, und die Verbrennungstemperatur derart verringern, dass sie niedriger als die Bildungstemperatur von thermischen Stickoxiden ist, wodurch die Konzentration von Stickoxiden (besonders Stickstoffoxid) im Verbrennungsprodukt in höchstem Maße verringert wird, während die Heizleistung gewährleistet wird.

The present disclosure has the following beneficial effects:

• The low-NOx burner nozzle provided in this disclosure uses a method of staged combustion in combination with turbulent combustion, converting the direction of the secondary air inlet from conventional perpendicularity to the axis of the burner nozzle to perpendicularity to the axis of the burner nozzle in a different plane is. Converting the direction of the secondary air intake enables turbulent flow to be generated because of the air revolution (no additional equipment is required), and the turbulent flow generated can slow down the mixing with flames, slowly increase the combustion intensity, and control the flames to keep them away from the initial combustion zone , and reduce the combustion temperature to be lower than the formation temperature of thermal nitrogen oxides, thereby reducing the concentration of nitrogen oxides (particularly nitrogen oxide) in the combustion product to the utmost while ensuring heating performance.

character list

• 1 Fig. 12 is a schematic diagram showing the external structure of a low-NOx burner nozzle;
• 2 Fig. 12 is a schematic diagram showing the internal structure of the low-NOx burner nozzle;
• 3 Fig. 12 is a partially enlarged schematic structural diagram of part A in 2 ;
• 4 Fig. 12 is a schematic diagram showing the direction of a conventional secondary air intake;
• 5 Fig. 12 is a schematic diagram showing the direction of the secondary air inlet of the low NOx combustor nozzle;
• 6 Figure 12 is a schematic plan view of a flame stabilizing disk;
• 7 Figure 12 is a schematic main view of the flame stabilizing disk; and
• 8th is a schematic sectional view along AA in 7 .

Reference List

1

air outer case;

11

air front housing;

111

tertiary air intake;

12

air center housing;

13

air rear housing;

131

total air intake;

14

outer air duct;

15

back cover;

2

air inner case;

21

flame ejection port;

22

initial combustion zone;

23

inner air duct;

24

primary air intake;

25

secondary air intake;

26

sealing device;

261

Flange;

27

fixation pin;

3

fuel gas pipeline;

31

tubular structure;

4

fuel gas housing;

41

fuel gas inlet duct;

42

second through hole;

5

flame stabilization disc;

51

hollow protrusion;

511

first through hole;

52

Tooth;

53

air circulation duct;

54

circle hole;

6

electronic spark plug;

61

electronic spark plug housing;

62

inner core electronic spark plug;

63

excitation device;

7

buffer rubber.

Detailed Description of Embodiments

In order to better understand the above technical solutions, exemplary embodiments of the present disclosure are to be described in detail below with reference to attached drawings. Although the exemplary embodiments of the present disclosure are illustrated in the accompanying drawings, it should be understood that the present disclosure can be embodied in various forms without being limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be more thorough and thorough, and will fully convey the scope of this disclosure to those skilled in the art.

like it in 1-8 As shown, the present disclosure provides a low NOx combustor nozzle wherein the concentration of nitrogen monoxide from its combustion products is at the comparatively low level. like it in 2 As shown, the low-NOx burner nozzle comprises an air outer casing 1, an air inner casing 2, and a fuel gas piping 3 which are sequentially coaxially jacketed from outside to inside. The area between the air outer case 1 and the air inner case 2 is an outer air duct 14; the area between the air inner case 2 and the fuel gas pipe 3 is an inner air duct 23; and the fuel gas piping 3 is a channel for fuel gas flow. like it in 1 and 2 As shown, the outer air case 1 comprises an air front case 11, an air center case 12, and an air rear case 13. The air front case 11 communicates with a heat treatment facility; the front open end of the air front case 11 is flush with the front open end of the air inner case 2 to form a flame ejection port 21; therefore, the air front case 11 is generally made of a high-temperature resistant alloy material, while compared to the air front case 11, the high-temperature resistance requirement of the air center case 12 and the air rear case 13 is low, and an ordinary metallic material can be used therefor. Press fitting or welding is commonly used for attachment of the air front housing 11 and the air center housing 12, and to facilitate the overhaul, a detachable connection for the air center housing 12 and the air rear housing 13 is designed.

like it in 1 and 2 As shown, the rear end face of the air outer case 1 communicates with a rear cover 15, the rear cover 15 communicates with a fuel gas case 4, a fuel gas inlet port 41 is provided in the fuel gas case 4, and the fuel gas inlet port 41 communicates with the fuel gas piping 3. The front closed end of the fuel gas pipe 3 is located behind the flame ejecting port 21 and is circumferentially provided with a circle of fuel gas nozzles, and the front closed end of the fuel gas pipe 3 is spaced from the flame ejecting port 21 . The fuel gas first flows into the fuel gas pipeline 3 through the fuel gas inlet passage 41 and is then ejected through the fuel gas nozzles.

A circle of fuel gas nozzles allows for better mixing of fuel gas with air and a larger volume of flame combustion; on the other hand, in the case of an opening at the front end, only an elongated flame would be generated in the axis direction of the burner nozzle, impairing the mixing. In the present embodiment, the fuel gas nozzles are evenly distributed in a dimension of 6×Φ6 mm at the front closed end of the fuel gas piping 3 .

like it in 2 1, a total air inlet 131 is provided at the rear of the air outer casing 1; the air inner case 2 is provided with a primary air inlet 24 and a secondary air inlet 25 located in front of the primary air inlet 24; and at least one circuit of tertiary air inlets 111 is still provided around the flame ejection port 21 on the front end surface of the air outer casing 1. In this embodiment, the primary air inlets 24 in a dimension of 6 × Φ12 mm are evenly distributed on the air inner case 2, are located in the circumferential direction of the part of the air rear case 13, and are perpendicular to the axis of the burner nozzle in the same plane; the secondary air inlets 25 are evenly distributed on the air inner case 2 in a dimension of 6 × Φ18 mm, are located in the circumferential direction of the part of the air front case 11, and are perpendicular to the axis of the burner nozzle in a different plane; and the tertiary air inlets 111 are evenly distributed around the flame ejection port 21 on the front end surface of the air front casing 11 in a dimension of 16×Φ10 mm an angle of 10° with the plane of the axis of the burner nozzle.

In the prior art, the extension direction line of the secondary air inlet 25 and the axis of the burner nozzle are in the same plane perpendicular to each other as shown in FIG 4 is shown, ie in the same plane there is a perpendicular relationship between the axis of the secondary air inlet 25 and the axis of the burner nozzle. On the other hand, in the present disclosure, the extension direction line of the secondary air inlet 25 and the axis of the burner nozzle are in different planes perpendicular to each other as shown in FIG 5 1, ie there is a perpendicular relationship between the axis of the secondary air inlet 25 and the axis of the burner nozzle in various planes.

By changing the direction of the secondary air inlet 25, the air introduced into the secondary air inlets 25 is rotated and turbulent flow is generated, thereby improving the degree of mixing of air with flame, so that the combustion amount of flames gradually increases (approximately the principle of flameless combustion), which can exert a “temperature lowering” effect to a greater extent on flames while realizing an oxidizing effect. In addition, the residence time of flames in the burner nozzle can be extended; and if the residence time is long, complete combustion of the fuel gas would be impossible because of the air content; therefore, a reducing atmosphere is presented, and then subsequent generation of nitrogen oxides is controlled.

like it in 2 As shown, the final stage of staged combustion is to introduce tertiary air; and in the present embodiment, the extending direction lines of all the tertiary air inlets 111 intersect at a point in front of the burner nozzle, and the directions of all the tertiary air inlets 111 form an angle of 10° with the axis of the burner nozzle. First of all, it must be clarified that air has two main effects on flames, on the one hand oxidizing effect, ie oxygen takes part in combustion, the more oxygen there is, the more violent the combustion is and the higher the combustion temperature, but more nitrogen oxides are produced; on the other hand, temperature-lowering effect for flames, a large amount of low-temperature air can take away the heat generated in combustion, which is advantageous for reducing the generation of nitrogen oxides. In addition, a comparatively small angle between the direction of tertiary air inlets 111 and the axis of the burner nozzle serves to better balance the relationship between the oxidizing effect of air and the temperature-lowering effect of air, and the formation of nitrogen oxides is reduced while ensuring heating performance. However, when the direction of the tertiary air inlets 111 is parallel to the axial direction of the burner nozzle, the temperature lowering effect is weakened and the oxidizing effect is better, which impairs the inhibition of the generation of nitrogen oxides. Therefore, the direction of the tertiary air inlets 111 must form a certain angle with the axis of the burner nozzle, then the oxidizing effect can be effectively reduced first, and the generation of nitrogen oxides is further reduced.

In order to increase the degree of mixing of the air with the fuel gas, a flame stabilizing disc 5 is provided in the air inner case 2, which creates a turbulent flow by rotating the air flowing through primary air inlets 24, flowing through the inner air duct 23, and mixed with fuel gas. like it in 6-8 As shown, the flame stabilizing disc 5 is a disc-shaped structure with a hollow protrusion 51 in the center, the inner space of the hollow protrusion 51 conforms to the outer contour of the front closed end of the fuel gas pipe 3, the outer diameter of the flame stabilizing disc 5 is equal to the inner diameter of the air inner casing 2 , and a circle of first through holes 511 is provided in the circumferential direction of the hollow projection 51 . When the flame stabilizing disc 5 cooperates with the front closed end of the fuel gas pipe 3, the plane of the disc-shaped structure is perpendicular to the axis of the burner nozzle, and the first through holes 511 are arranged in one-to-one correspondence with the fuel gas nozzles. The edge of the flame stabilizing disk 5 is a serrated structure; each tooth 52 of the toothed structure is arranged so as to form an inclination angle of 45° with the plane of the disc-shaped structure; the distance between each adjacent teeth 52 forms an air circulation channel 53 with an inclination angle; and when the air passes through the air circulation passage 53, a turbulent flow is generated by rotation of the air.

After being mixed with the fuel gas, primary air is ignited by an electronic spark plug 6 . like it in 2 As shown, the electronic spark plug 6 comprises an electronic spark plug case 61 and an inner core electronic spark plug 62, the electronic spark plug case 61 is coaxially encased outside of the inner core electronic spark plug 62, and the inner core electronic spark plug 62 is longer than the electronic spark plug case 61. A second through hole 42, which is perpendicular to the fuel gas inlet passage 41, is provided at the bottom of the fuel gas inlet passage 41 in the fuel gas casing 4; the outer wall of the fuel gas piping 3 is provided with a tubular structure 31 parallel to the fuel gas piping 3; the flame stabilizing disc 5 is provided with a circular hole 54; the axes of the second through hole 42, the tubular structure 31, and the circular hole 54 are collinear, and the diameters of the second through hole 42, the tubular structure 31, and the circular hole 54 are matched to the outer diameter of the electronic spark plug housing 61. The electronic spark plug housing 61 is continuously arranged in the second through hole 42, in the tubular structure 31, and in the circular hole 54 so that it is fixed in the burner nozzle; then the head of the electronic spark plug inner core 62 exceeds the front closed end of the fuel gas piping 3 while the tail remains outside of the fuel gas casing 4; and the area between the tip of the electronic spark plug inner core 62 and the flame ejection port 21 forms an initial combustion zone 22. The tail of the electronic spark plug 6 communicates with an excitation device 63 to receive a high-voltage pulse current fed from a high-voltage line and discharge through the To allow head of the inner core electronic spark plug 62 so that an electric spark is generated by breakdown of the gas mixture and thereby the gas mixture is ignited.

like it in 2 and 3 As shown, there is a connection interface in the fuel gas piping 3 and the fuel gas inlet passage 41; and in order to ensure safety and prevent gas leakage, a sealing jig 26 is provided at the rear open end of the air inner casing 2 in the inner air duct 23, and the rear face plane of the sealing jig 26 is in contact with the fuel gas casing 4.

Since the air outer case 1, the air inner case 2, and the fuel gas pipe 3 are all made of a metallic material, a buffer rubber 7 is provided between the sealing jig 26 and the air inner case 2 to reduce friction and abrasion between the metals. More specifically, a flange 261 is provided at the rear end of the sealing jig 26, and the buffer rubber 7 is located between the flange 261 and the air inner case 2.

Furthermore, the air outer case 1, the air inner case 2, and the fuel gas piping 3 are detachably connected to each other to facilitate the overhaul; therefore, two fixing pins 27 are provided on the outer wall of the rear open end of the air inner case 2 so as to be symmetrical with the axis of the burner nozzle as the center, and two positioning grooves are provided on the inner wall of the rear open end of the air outer case 1 so as to be aligned with are symmetrical with the axis of the burner nozzle as the center, with the two fixing pins 27 cooperating with the two positioning grooves to facilitate positioning at the time of assembly.

In order for the burner nozzle to achieve better combustion effect, an inspection window is provided on the fuel gas casing 4, while an inspection glass is provided at a position in the flame stabilizing disk 5 corresponding to the inspection window, the ignition condition of the electronic spark plug 6 being easily observed through the inspection window and inspection glass. In addition, a fuel gas flow meter and an air flow meter are provided on the fuel gas case 4 and the total air inlet 131, respectively, whereby the flow can be monitored and regulated at all times to ensure a better combustion effect.

It is to be understood that the term "front" in the present disclosure is understood as the ejection direction of flames, and the term "rear" refers to a direction opposite to the "front" direction.

• In der vorliegenden Ausführungsform beträgt die Leistung der Brennerdüse 220 kW, beim Gebrauch der Brennerdüse ist das Luftvordergehäuse 11 mit einer externen Wärmebehandlungsanlage verbunden, der Gesamtlufteinlass 131 steht mit einem externen Luftverdichter in Verbindung, um die Brennerdüse mit für die Verbrennung erforderlichem Sauerstoff zu versorgen, und der Brenngaseinlasskanal 41 steht mit einer Erdgasrohrleitung in Verbindung, um die Brennerdüse mit einem Brennstoff zu versorgen. Sicherheitshalber werden Luft und Brenngas beim Betrieb der Brennerdüse in folgender Reihenfolge eingeführt: die Luft wird zuerst eingeführt, das Brenngas wird beim stabilisierten Luftdurchfluss eingeführt, und das Gasgemisch aus Luft und Brenngas wird dann zum Brennen entzündet. Im Einzelnen wird die Luft zuerst in den Gesamtlufteinlass 131 eingeführt; und die Luft strömt in dem äußeren Luftkanal 14 nach vorne, tritt durch den primären Lufteinlass 24 in den inneren Luftkanal 23 ein und strömt weiter nach vorne, und eine turbulente Strömung wird durch die Flammenstabilisierungsscheibe 5 erzeugt. Dann wird das Brenngas in den Brenngaseinlasskanal 41 eingeführt, und das Brenngas strömt in die Brenngasrohrleitung 3 ein und strömt nach vorne, und dann nach dem Durchgang durch die Flammenstabilisierungsscheibe 5 ausgestoßen, wobei das Brenngas mit primärer Luft, die eine turbulente Strömung bildet, ausreichend vermischt wird. Anschließend wird das Gasgemisch aus primärer Luft und dem Brenngas mittels der elektronischen Zündkerze 6 entzündet, so dass das Gasgemisch in der anfänglichen Verbrennungszone 22 brennt. Zu diesem Zeitpunkt ist die Brennstoffkonzentration hoch, während die Sauerstoffkonzentration niedrig ist, was zur brennstoffreichen und sauerstoffarmen Phase gehört; der Durchfluss primärer Luft pro Zeiteinheit ist geringer als die theoretische Luft, die für die Brenngasverbrennung erforderlich ist; daher ist die Verbrennungsintensität schwach, die Verbrennungstemperatur ist niedrig, und die Verbrennung findet nur in einem kleinen Bereich statt, und nur eine geringe Menge an Stickoxiden wird erzeugt.

The combustion process of the low NOx burner nozzle according to the present disclosure is as follows:

• In the present embodiment, the power of the burner nozzle is 220 kW, when using the burner nozzle, the air front body 11 is connected to an external heat treatment facility, the total air inlet 131 is connected to an external air compressor to supply the burner nozzle with oxygen necessary for combustion, and the fuel gas inlet passage 41 communicates with a natural gas pipeline to supply a fuel to the burner nozzle. For safety's sake, when the burner nozzle operates, air and fuel gas are introduced in the following order: the air is introduced first, the fuel gas is introduced at the stabilized air flow rate, and then the mixed gas of air and fuel gas is ignited to burn. Specifically, the air is first introduced into the overall air inlet 131; and the air flows forward in the outer air duct 14, enters the inner air duct 23 through the primary air inlet 24 and further flows forward, and turbulent flow is stabilized by the flame sion disc 5 generated. Then, the fuel gas is introduced into the fuel gas inlet port 41, and the fuel gas flows into the fuel gas piping 3 and flows forward, and then ejected after passing through the flame stabilizing disk 5, the fuel gas sufficiently mixing with primary air forming a turbulent flow becomes. Then, the mixed gas of the primary air and the fuel gas is ignited by the electronic spark plug 6 so that the mixed gas burns in the initial combustion zone 22 . At this time, the fuel concentration is high while the oxygen concentration is low, which belongs to the fuel-rich and oxygen-lean phase; the flow rate of primary air per unit time is less than the theoretical air required for fuel gas combustion; therefore, the combustion intensity is weak, the combustion temperature is low, and combustion takes place only in a small area, and only a small amount of nitrogen oxides is generated.

Thereafter, the air flowing forward in the outer air duct 14 flows through the secondary air inlets 25 into the initial combustion zone 22; after changing the direction of the secondary air inlets 25 of the low-NOx burner nozzle, the air is not directly sprayed into the initial combustion zone 22, but swirls along the inner wall of the air inner casing 2 and is slowly mixed with the gas mixture in the initial combustion zone 22, thereby slowly increasing the combustion intensity becomes. At this time, the speed of the flames ejected from the flame ejection port 21 is much lower than the flame speed of the conventional structure.

Subsequently, the air flowing forward in the outer air duct 14 flows into the heat treatment facility through the tertiary air inlets 111 for further supplementation, so that the combustion intensity is further enhanced. However, the angle between the direction of tertiary air inlets 111 and the axis of the burner nozzle is comparatively small, so the air can cover more areas alternately, whereby the combustion takes place in a larger area and the flame temperature in the heat treatment facility is reduced significantly. At this time, the combustion intensity and the combustion temperature are still at a relatively low level, the high-temperature aggregation phenomenon is reduced, and the concentration of thermal nitrogen oxides is then suppressed.

Finally, when stopping the operation, the introduction of fuel gas from the fuel gas inlet duct 41 is shut off first, and the introduction of air from the total air inlet 131 is then shut off after the flame is gradually extinguished to avoid the danger of tempering.

In summary, the low-NOx burner nozzle according to the present disclosure can change the direction of the secondary air inlet 25 without the help of other equipment to turn the air to generate turbulent flow, and staged combustion and turbulent combustion are combined with each other, thereby increasing the effect of the air of the combustion intensity is slowed down and the emission concentration of NOx is reduced.

At the same time, a comparatively small angle between the direction of tertiary air inlets 111 and the axis of the burner nozzle can allow the actual air-fuel ratio to exceed the theoretical air-fuel ratio, so that excessive cold air covers a larger area, a better temperature lowering effect for Flames can be provided, and the concentration of nitrogen oxides in the combustion product is further reduced. (The air/fuel ratio determines the completeness of combustion: at the small air/fuel ratio, the fuel gas is in excess, while the air (oxygen) is insufficient, resulting in wasted energy; at the large air/fuel ratio, the air is excess, the fuel gas is completely burned, and the remaining air carries the heat away.)

In the following, comparative tests were carried out with regard to conventional burner nozzles and various developments of the burner nozzle according to the present disclosure.

Test conditions were as follows: Initial conditions were set to a fuel gas flow rate of 21.6 m ³ /h, a fuel gas pressure of 120 kPa, a temperature of 20°C, a component of methane CH4 of 100%, a fuel gas inlet velocity of 26.5 m /s, an air flow of 250 m ³ /h, an air pressure of 160 kPa, and a temperature of 20°C. The volume ratio for staged air was primary air: secondary air: tertiary air = 0.2:0.45:0.35. The primary air inlet velocity was 20.5 m/s, the secondary air inlet velocity was 20.5 m/s, the tertiary air inlet velocity was 7.44 m/s, and the air component was anyway air with an oxygen mass fraction of 23, 2% The dimensions of the combustion chamber were 2800 mm × 1600mm×1900mm; and the outlet was set to the standard atmospheric pressure of 1 atm.

Test results were as follows:

Structure of conventional burner nozzle (in which the secondary inlet direction was in the same plane perpendicular to the axis direction of the burner nozzle and the tertiary inlet angle was 20°): the combustion chamber temperature was 505.06°C, and the molar volume fraction of nitrogen monoxide resulting from combustion was 54.8 ppm.

Structural Improvement 1 of the present disclosure (in which the secondary inlet direction was changed to be in a different plane perpendicular to the axis direction of the burner nozzle, and the tertiary inlet angle was 20°): the combustor temperature was 491.05°C, and the molar volume fraction was nitrogen monoxide resulting from combustion was 23.9 ppm.

Structural development 2 of the present disclosure (in which the secondary inlet direction was in the same plane perpendicular to the axis direction of the burner nozzle, and the tertiary inlet angle was 15°): the combustor temperature was 491.74°C, and the molar volume fraction of nitrogen monoxide resulting from combustion was 31 .5 ppm.

Structural development 3 of the present disclosure (in which the secondary inlet direction was in the same plane perpendicular to the axis direction of the burner nozzle, and the tertiary inlet angle was 10°): the combustor temperature was 490.68°C, and the molar volume fraction of nitrogen monoxide resulting from combustion was 30 .2ppm.

From the above data, it is shown that by the present disclosure, the reduction in combustor temperature is maintained within 3%, while the effect of reducing nitrogen monoxide emission from the burner nozzle is very evident, with the reduction rates being 56.4%, 42.5%, respectively %, and 44.9% of the conventional burner nozzle structure, indicating that the present disclosure is very effective in reducing nitrogen monoxide during the combustion process of the burner nozzle, and in aspects of controlling pollution emissions from the burner nozzle and realizing " "environmentally friendly" combustion, the present disclosure makes a lot of sense.

In the explanation of this specification, the explanation uses terms such as "an embodiment", "some embodiments", "embodiment", "example", "specific example", or "some examples" etc. to indicate that specific features, Structures, materials, or features related to this embodiment or example are included in at least one embodiment or example of this disclosure. In this description, schematic expressions of the above terms do not necessarily refer to the same embodiment or the same example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, the person skilled in the art could combine and combine different embodiments or examples and features from different embodiments or examples explained in this description without causing mutual contradiction.

Although the embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of this disclosure, and changes, modifications, substitutions, and alterations may occur to those skilled in the art within the scope of this disclosure could make the above embodiments.

Summary

The present disclosure relates to the technical field of combustors, and more particularly relates to a low NOx combustor nozzle. This burner nozzle comprises an outer air case, an inner air case, and a fuel gas pipe lined coaxially from the outside to the inside in sequence, the inner air case being provided with a primary air inlet and a secondary air inlet located in front of the primary air inlet, the extension direction line of the secondary Air inlet is in a different plane perpendicular to the axis of the burner nozzle, and the front end face of the outer air casing is still provided with a tertiary air inlet. This changes the direction of the secondary air inlet of this burner nozzle, so that a turbulent flow is generated because of the air revolution, and the generated turbulent flow can slow down the mixing with flames, slowly increase the combustion intensity, and reduce the combustion temperature to be lower than that Formation temperature of thermal nitrogen oxides, whereby the goal of significantly reducing emission concentrations of nitrogen oxides is achieved.

Claims (10)

A low-NOx burner nozzle characterized by comprising an air outer case (1), an air inner case (2), and a fuel gas duct (3) which are coaxially jacketed from outside to inside in succession, the front open end of the air outer case (1) is flush with the front open end of the air inner case (2) to form a flame ejection port (21); the front closed end of the fuel gas pipe (3) is behind the flame ejection opening (21) and is spaced from the flame ejection opening (21); the area between the air outer case (1) and the air inner case (2) is an outer air duct (14); the area between the air inner casing (2) and the fuel gas pipe (3) is an internal air duct (23); a total air inlet (131) is provided at the rear of the air outer case (1); the air inner casing (2) is provided with a primary air inlet (24) and a secondary air inlet (25) located in front of the primary air inlet (24); the extension direction line of the secondary air inlet (25) perpendicular to the axis of the burner nozzle is in a different plane; and the front end surface of the air outer casing (1) is further provided with a tertiary air inlet (111). Low-NOx emission burner nozzle claim 1 , characterized in that at least one circle of the tertiary air inlets (111) is provided around the flame ejection port (21), the extending direction lines of all the tertiary air inlets (111) intersect at a point in front of the burner nozzle, and the directions of all the tertiary air inlets (111) form an angle of 10°-15° with the axis of the burner nozzle. Low-NOx emission burner nozzle claim 1 , characterized in that the rear end surface of the air outer housing (1) is connected to a rear cover (15), the rear cover (15) is connected to a fuel gas housing (4), a fuel gas inlet channel (41) is provided in the fuel gas housing (4). and the fuel gas inlet port (41) is in communication with the fuel gas piping (3); and a circuit of fuel gas nozzles is provided in the circumferential direction of the front closed end of the fuel gas pipeline (3). Low-NOx emission burner nozzle claim 3 characterized in that it further comprises a flame stabilizing disc (5) located in the air liner (2); the flame stabilizing disc (5) is a disc-shaped structure with a hollow protrusion (51) in the center, the interior of the hollow protrusion (51) coincides with the outer contour of the front closed end of the fuel gas pipe (3), the outer diameter of the flame stabilizing disc (5) is the same is the inner diameter of the air inner casing (2), a circle of first through holes (511) is provided in the circumferential direction of the hollow projection (51), the edge of the flame stabilizing disk (5) is a serrated structure, each tooth (52) of the serrated structure is such is arranged to form an inclination angle of 45° with the plane of the disc-shaped structure, and the distance between each adjacent teeth (52) forms an air circulation channel (53); and the plane of the disc-shaped structure is perpendicular to the axis of the burner nozzle, and the first through holes (511) are arranged in one-to-one correspondence with the fuel gas nozzles when the flame stabilizing disc (5) is connected to the front closed end of the fuel gas pipe (3 ) works together. Low-NOx emission burner nozzle claim 4 characterized in that it further comprises an electronic spark plug (6), the electronic spark plug (6) comprising an electronic spark plug housing (61) and an inner electronic spark plug core (62), the electronic spark plug housing (61) coaxially outside the inner electronic core spark plug (62) is covered, and the inner core of electronic spark plug (62) is longer than the electronic spark plug shell (61); a second through hole (42) perpendicular to the fuel gas inlet port (41) is provided at the bottom of the fuel gas inlet port (41) in the fuel gas casing (4), the outer wall of the fuel gas piping (3) having a tubular structure (31) parallel to the fuel gas pipeline (3), the flame stabilizing disk (5) is provided with a circular hole (54), the axes of the second through hole (42), the tubular structure (31), and the circular hole (54) are collinear, and the diameters of the the second through hole (42), the tubular structure (31), and the circular hole (54) are fitted to the outer diameter of the electronic spark plug housing (61); and the electronic spark plug housing (61) is continuously arranged in the second through hole (42), in the tubular structure (31), and in the circular hole (54) so that it is fixed in the burner nozzle, the area between the head of the forms an initial combustion zone (22) between the electronic spark plug (6) and the flame ejection port (21), and the tail of the electronic spark plug (6) remains outside the combustible gas casing (4). Low-NOx emission burner nozzle claim 3 , characterized in that a sealing device (26) is provided at the rear open end of the inner air casing (2) in the inner air duct (23), the rear end plane of the sealing device (26) is in contact with the fuel gas casing (4), and the rear end the sealing device (26) is provided with a flange (261). Low-NOx emission burner nozzle claim 6 , characterized in that a buffer rubber (7) is provided between the flange (261) and the air inner case (2). Low-NOx emission burner nozzle claim 1 , characterized in that two fixing pins (27) are provided on the outer wall of the rear open end of the air inner case (2) so as to be symmetrical with the axis of the burner nozzle as the center, and two positioning grooves are provided on the inner wall of the rear open end of the Air outer casing (1) are provided to be symmetrical with the axis of the burner nozzle as the center, the two fixing pins (27) cooperating with the two positioning grooves. Low-NOx emission burner nozzle claim 5 , characterized in that the tail of the electronic spark plug (6) communicates with an excitation device (63). Low-NOx emission burner nozzle claim 1 , characterized in that the outer air housing (1) comprises a front air housing (11), a middle air housing (12) and a rear air housing (13), the middle air housing (12) and the rear air housing (13) being detachably connected to one another.

Images