Staged air control low-nitrogen combustion jet flow burner structure

Abstract

The invention discloses a staged air control low-nitrogen combustion jet flow burner structure which comprises a fuel pipe coaxially arranged in a burner shell in a penetrating mode, the outlet end of the fuel pipe is a blind end, the side portion of the outlet end of the fuel pipe is provided with a radial jet flow nozzle in a connected mode, and an overflowing distance is formed between the radial jet flow nozzle and the burner shell. Fuel and combustion-supporting air are subjected to cross jet flow in the overflowing distance to form mixed gas; a center jet pipe is arranged in the blind end of the fuel pipe, an air inlet of the center jet pipe penetrates through the fuel pipe in the radial direction on the upstream of the flame stabilizing disc and faces the inlet end, and an air outlet of the center jet pipe penetrates through the blind end to form a jet nozzle. A combustion-supporting air inlet pipe is arranged on the side, close to the inlet end, of the burner shell. A fuel-combustion-supporting air cross jet flow mixing technology is adopted, so that the mixing effect of fuel and air is enhanced, the combustion efficiency is improved, and emission of nitric oxide is reduced. And stable combustion can be achieved under the wide-range working condition through the flame stabilizing disc. The overall structure is simple, machining difficulty is small, and cost is low.

Description

Technical Field

[0001] The present invention relates to the technical field of combustion devices, and in particular to a staged air-controlled low-nitrogen combustion jet burner structure. Background Art

[0002] In industrial combustion equipment, jet burners are the core components for the mixed combustion of fuel and combustion air, and their structural design directly affects the combustion efficiency and pollutant emissions. Existing jet burners usually adopt a method of direct cross-jet mixing of fuel and combustion air. After the fuel is ejected through the radial nozzle, it is quickly mixed and burned in the furnace with the combustion air flowing axially along the burner shell. Specifically, in the existing technology, the combustion air mostly enters the inner cavity of the shell perpendicular to the axial direction through the inlet pipe on the burner shell, and the fuel radially ejected from the inner cavity of the shell and the head of the fuel pipe form a cross jet, and the mixed gas directly enters the furnace to complete the combustion process; in order to stabilize the flame, a flame stabilizing disk is often provided at the burner head, and the annular gap between it and the shell is used to form a low-pressure reflux zone to prevent the flame from becoming unstable.

[0003] However, the existing technology has significant defects: first, the combustion-supporting air has a short mixing path with the fuel after vertical intake and insufficient mixing time, which causes the air-fuel ratio in the local area to be close to the theoretical combustion ratio, forming a high-temperature concentrated area (the temperature often exceeds 1500°C). Under this temperature condition, nitrogen is easily oxidized to produce a large amount of thermal nitric oxide, causing nitrogen oxide emissions to exceed the standard, seriously affecting environmental protection indicators; second, the combustion-supporting air enters the mixing area at one time, and the secondary air directly impacts the initial combustion area, intensifying the combustion intensity, causing the flame temperature and flow rate to rise sharply, and further promoting the generation of thermal nitric oxide; third, although the tertiary air is used to supplement the oxygen required for combustion, due to the large intake angle and insufficient flow rate control, it is difficult to effectively cover the high-temperature area at the tail of the flame, the cooling effect is limited, and the continuous generation of nitrogen oxides cannot be suppressed; in addition, the fuel nozzle flow uniformity of some burners is poor, resulting in local rich combustion or oxygen enrichment, which not only reduces the combustion efficiency, but also aggravates pollutant emissions due to local high temperature or incomplete combustion.

[0004] The core cause of these defects is that existing technologies fail to implement graded control of the combustion air, resulting in a lack of precise guidance for the mixing and combustion processes. This leads to uneven air-fuel ratio distribution and difficulty controlling high-temperature areas. Therefore, a jet burner structure that optimizes the combustion air supply, improves mixing uniformity, and suppresses localized high temperatures is urgently needed to address the existing issues of excessive nitrogen oxide emissions and insufficient combustion efficiency. Summary of the Invention

[0005] The purpose of the present invention is to overcome the defects in the prior art and provide a staged air control low nitrogen combustion jet burner structure.

[0006] To achieve the above object, the technical solution of the present invention is as follows: A graded air-controlled low-nitrogen combustion jet burner structure comprises a burner shell, which is in the shape of a circular tube with two ends open, one end being an inlet end and the other end being an outlet end; a fuel pipe is coaxially provided through the burner shell, the fuel pipe is set as a blind end at the outlet end, and a plurality of radial jet nozzles arranged radially are connected to the side of the fuel pipe at the outlet end, the radial jet nozzle is provided with a flame stabilizing disk on the side away from the outlet end, and a flow gap is provided between the radial jet nozzle and the burner shell, so that the fuel and the combustion-supporting air cross-jet within the flow gap to form a mixed gas; the fuel pipe is provided with a central jet pipe in its blind end, the air inlet of the central jet pipe radially passes through the fuel pipe upstream of the flame stabilizing disk and is arranged toward the inlet end, and its air outlet passes through the blind end to form a jet nozzle; the burner shell is provided with a combustion-supporting air inlet pipe on the side close to the inlet end.

[0007] Furthermore, it also includes a graded air intake system for graded regulation of the combustion-supporting air. The graded air intake system includes a primary air structure, a secondary air structure, and a tertiary air structure, which divides the combustion-supporting air into primary air, secondary air, and tertiary air. The primary air is initially mixed with the fuel, the secondary air suppresses the combustion intensity, and the tertiary air accurately cools down.

[0008] Furthermore, the primary air structure includes an annular premixing chamber, which is arranged in an annular flow gap. The annular premixing chamber has an outlet on one side facing the outlet end and forms an annular outlet. The radial jet nozzle is connected to the inner ring of the annular premixing chamber; the outer ring of the annular premixing chamber is circumferentially connected and a plurality of air guide holes are arranged. The air guide holes enter the radial jet nozzle along the tangential direction. The air guide holes form a rotating airflow in the annular premixing chamber, form a rotating cross jet with the radially injected fuel, and extend the mixing path under the rotating motion.

[0009] Furthermore, the secondary air structure includes an annular inner shell arranged on the outer periphery of the annular premixing chamber, and an annular duct is formed between the annular inner shell and the burner shell. The air guide hole passes through the annular inner shell and is connected to the annular duct. The annular duct enters the annular premixing chamber from the air guide hole to form primary air, and is ejected through the annular duct to form secondary air.

[0010] Furthermore, a spiral air guide belt is provided in the annular duct, and the spiral air guide belt is multiple and wound in the same direction; a diverter ring is provided on the annular inner shell, and the diverter ring is arranged downstream of the air guide hole inlet.

[0011] Furthermore, the tertiary air structure includes a porous cooling ring cavity, which is an annular cavity arranged on the outer periphery of the outlet end of the burner shell. The porous cooling ring cavity has a number of micro spray holes evenly distributed along the circumference toward the furnace side. The porous cooling ring cavity is connected to the combustion air inlet pipe through the air inlet pipe.

[0012] Furthermore, the porous cooling ring cavity is adjustable in the axial direction of the burner shell, the porous cooling ring cavity is slidingly connected to the burner shell through an axial slide rail, and a driving mechanism of the porous cooling ring cavity is arranged in the normal temperature zone of the outer wall of the burner shell.

[0013] Furthermore, the micro-spray holes are arranged to be inclined 15 degrees radially outward, so that the tertiary air covers the high-temperature area outside the tail of the flame.

[0014] Furthermore, the central jet tube is provided with a reflux injection structure, which includes a Venturi tube portion arranged in the central jet tube, the Venturi tube portion is located at the radial jet nozzle, and the narrow part of the Venturi tube is provided with a drainage tube radially passing through the fuel pipe, the drainage tube is located on the side of the flame stabilizing disk toward the outlet end, and the drainage tube is provided with multiple drainage holes on the side toward the outlet end.

[0015] The advantages and benefits of the present invention include: It utilizes fuel-combustion air cross-jet mixing technology to enhance fuel-air mixing, improve combustion efficiency, and reduce nitrogen oxide emissions. The flame stabilization disk enables stable combustion under a wide range of operating conditions. It also features a simple overall structure, minimal processing difficulty, and low cost.

[0016] The hierarchical collaborative design of the present invention forms a stepped regulation of "mixing-temperature control-cooling" through primary air swirl premixing, secondary air swirl wrapping, and tertiary air targeted cooling, breaking through the limitation of the single air path of the traditional burner; the axial adjustment of the tertiary air and the flow distribution of the secondary air enable the burner to adapt to different fuels and loads, solving the problem of poor adaptability of traditional burners. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a structural schematic diagram of a graded air-controlled low-nitrogen combustion jet burner structure of the present invention; Figure 2 1 is a schematic longitudinal section diagram of a jet burner according to a first embodiment of the present invention; Figure 3 1 is a schematic cross-sectional view of a radial jet nozzle of a jet burner according to an embodiment of the present invention; Figure 4 This is an exploded view of a jet burner according to a second embodiment of the present invention; Figure 5 1 is a schematic longitudinal section diagram of a jet burner according to a second embodiment of the present invention; In the figure: 1. Burner shell; 2. Outlet end; 3. Fuel pipe; 4. Blind end; 5. Radial jet nozzle; 6. Flame stabilizing disk; 7. Central jet tube; 8. Jet nozzle; 9. Combustion air inlet pipe; 10. Annular premixing chamber; 11. Annular outlet; 12. Air guide hole; 13. Annular inner shell; 14. Annular duct; 15. Spiral air guide belt; 16. Diverter ring; 17. Multi-porous cooling ring cavity; 18. Micro-spray hole; 19. Air inlet pipe; 20. Axial slide rail; 21. Venturi tube; 22. Drainage pipe; 23. Drainage hole; 24. Circular hole; 25. Folded edge. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention are further described below in conjunction with the examples. The following examples are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] Example 1: A graded air control low nitrogen combustion jet burner structure, such as Figure 1-3 As shown, it includes a burner shell 1, which is in the shape of a circular tube with two ends open, one end being the inlet end and the other end being the outlet end 2. The main body of the burner shell 1 is a circular tube structure. The burner shell 1 is provided with a combustion air inlet pipe 9 on the side near the inlet end, and is connected to the external air supply system through a flange connection. A fuel pipe 3 is coaxially provided through the burner shell 1. The fuel pipe 3 is a straight fuel pipe arranged in the center of the burner shell 1, located on the central axis of the burner, and is used to transport fuel to the burner head; the fuel pipe 3 is provided with a blind end 4 at the outlet end 2, and a plurality of radial jet nozzles 5 arranged radially are connected to the side of the outlet end 2 of the fuel pipe 3. Specifically, near the head of the fuel pipe 3, six radial fuel spray holes evenly arranged in the circumference are opened on the surface of the fuel pipe 3. The even spray holes are installed one-to-one with the jet nozzles, so that the fuel can be sprayed evenly in the circumference of the jet nozzle. The head of the fuel pipe 3 is welded with a plug to form a blind end 4.

[0020] A flame stabilizing disk 6 is provided on the side of the radial jet nozzle 5 away from the outlet end 2. The disk 6 is located on the side of each radial jet nozzle 5 and is used to create a low-pressure zone. The disk 6 is a circular disc with an outer diameter flush with the outlet of the radial jet nozzle 5, forming an annular gap between the radial jet nozzle 5 and the outer periphery of the disk 6 and the burner housing 1. The disk 6 is connected to the outer wall of the fuel pipe 3 on the inside, and the front end of the disk 6 abuts the wall of the radial jet nozzle 5. The disk 6 has multiple circular holes 24 of equal size arranged between the radial jet nozzles 5 to reduce the temperature of the radial jet nozzle 5 and the baffle wall. The disk structure creates a certain obstruction, accelerating the airflow around the disk 6. Combined with the jet entrainment effect, a local low pressure is formed on the front side. Pressure equilibrium is then maintained through flue gas recirculation, ultimately forming a stable low-pressure zone near the front end. This area anchors the flame root, preventing the flame from destabilizing due to airflow disturbances, thereby achieving stable combustion. In this embodiment, the size and position layout of the circular holes 24 between each radial jet nozzle 5 are the same, and the position layout of the circular holes 24 between each radial jet nozzle 5 is symmetrical. Three circular holes 24 of the same size are evenly arranged radially at the center position between two adjacent radial jet nozzles 5, and one circular hole 24 is set close to the radial jet nozzle 5.

[0021] A flow clearance is provided between the radial jet nozzles 5 and the burner housing 1, allowing the fuel and combustion air to intersect within this clearance to form a mixed gas. Specifically, the radial jet nozzles 5 are evenly distributed circumferentially around the head of the fuel pipe 3. Fuel enters each radial jet nozzle 5 through uniformly distributed small holes at the head and is ejected straight out, intersecting with the combustion air to form a mixed gas. The mixed gas then enters the furnace for combustion. A certain distance is maintained between the outlet of the radial jet nozzles 5 and the burner housing 1 to form a transverse jet and ensure sufficient mixing.

[0022] The fuel pipe 3 is provided with a central jet pipe 7 in its blind end 4. The air inlet of the central jet pipe 7 radially passes through the fuel pipe upstream of the flame stabilizing disk 6 and is arranged toward the inlet end. The air outlet passes through the blind end 4 to form a jet nozzle 8. Specifically, the central jet pipe 7 is a connecting pipe connected between the blind end 4 and the wall of the fuel pipe 3, which is used to lead the air outside the fuel pipe 3 to the vicinity of the head of the fuel pipe 3. The pipe is flush with the blind end 4 at the head of the fuel pipe 3 and is located at the central axis of the fuel pipe 3. It radially passes through the fuel pipe 3 at a certain distance from the nozzle on the fuel pipe 3. The position from the nozzle is mainly to reduce the impact on the uniformity of the flow rate of each nozzle. The inlet of the central jet pipe 7 is at a certain distance from the surface of the fuel pipe 3 to reduce the impact of the wall surface, and the inlet of the central jet pipe 7 is parallel to the direction of the combustion air flow. The central jet tube 7 introduces the air from the outside of the fuel tube 3 to the vicinity of the head of the fuel tube 3. The air introduced by the central jet tube 7 flows along the central axis of the burner, forming a cross airflow with the radial fuel jet, increasing the contact area and mixing intensity of the fuel and air, and avoiding the problem of uneven mixing of the fuel due to local air shortage in the early stage of fuel ejection. The central jet tube 7 enhances the initial mixing effect of the fuel and air and ensures the uniformity of fuel injection through precise air introduction and optimized position design, thereby achieving efficient and stable combustion of the burner.

[0023] Example 2: This embodiment is improved on the basis of the structure of the previous embodiment. By dividing the combustion-supporting air into primary air, secondary air, and tertiary air, this embodiment realizes the coordinated regulation of staged mixing-temperature control-temperature cooling, and utilizes the effects of jet mixing, swirl enhancement, targeted temperature control, etc. in fluid mechanics to solve the problem of excessive nitrogen oxides caused by uneven mixing and local high temperature in traditional burners.

[0024] Specifically, if Figure 4 、 5 As shown, the primary air structure includes an annular premixing chamber 10, which is located within the annular gap (i.e., the annular space between the radial jet nozzle 5 and the burner housing 1). Its outlet is an annular opening facing the furnace, and the fuel outlet of the radial jet nozzle 5 is connected to the inner ring of the premixing chamber. A plurality of air guide holes 12 are evenly distributed around the outer ring. The air guide holes 12 enter the premixing chamber tangentially and form a rotating cross jet with the radially injected fuel. In actual use, in order to improve the injection intensity and fuel injection distance, the inner and outer rings of the annular opening can be designed with a folded edge 25 to form a narrowed annular opening. Due to the shielding effect of the folded edge 25 on the mixed fluid, the mixing effect of the fuel and the combustion-supporting air can be further enhanced.

[0025] The tangential arrangement of the air guide holes 12 creates a swirling flow when the combustion-supporting air enters the premixing chamber. This creates a swirl effect on the airflow, which in turn forms a "swirling cross jet" with the radially ejected fuel. The fuel diffuses radially outward, while the swirling airflow moves circumferentially. The two intersect and overlap, extending the mixing path 3-5 times longer than a straight jet, significantly improving mixing uniformity. The annular outlet 11 allows the premixed mixture to flow smoothly into the furnace along the axial direction, preventing localized airflow from impacting the furnace walls while reserving space for subsequent secondary air supply.

[0026] Specifically, the annular premixing chamber 10 has an inner diameter of 120 mm, an outer diameter of 150 mm, and an axial length of 80 mm; the number of air guide holes 12 is 8, with a diameter of 10 mm (inlet) / 8 mm (outlet), which are arranged tangentially along the outer circle of the premixing chamber to ensure moderate swirl intensity; there are six radial jet nozzles 5, with a diameter of 8 mm, which are evenly distributed circumferentially.

[0027] The secondary air structure includes an annular inner shell 13 arranged on the outer periphery of the annular premixing chamber 10. The annular inner shell 13 is sleeved on the outer periphery of the annular premixing chamber 10 and forms an annular duct 14 with the burner shell 1. The air guide hole 12 passes through the annular inner shell 13 and connects to the annular duct 14. Part of the combustion-supporting air entering the annular duct 14 enters the premixing chamber through the air guide hole 12 to become the primary air, and part of it is directly ejected through the annular duct 14 to become the secondary air. A plurality of spiral air guide belts 15 with the same rotation direction are provided in the duct, and a diverter ring 16 is provided on the annular inner shell 13 downstream of the inlet of the air guide hole 12. The diverter ring 16 is used to realize the flow distribution function. The diverter ring 16 is located downstream of the inlet of the air guide hole 12. It can distribute the combustion-supporting air in the annular duct 14 as needed through the structural shape (such as the arc-shaped convex surface) - part of it enters the air guide hole 12, and the other part flows along the duct to avoid the imbalance of air volume due to local resistance differences.

[0028] The spiral air guide belt 15 makes the combustion-supporting air entering the annular duct 14 form a rotating airflow. When it flows along the axis of the burner to the furnace, it "wrapped" the oxygen from the periphery of the flame, avoiding direct impact on the initial combustion zone to prevent a sudden increase in combustion intensity, and prolonging the mixing time with the unburned fuel through the swirl to suppress local high temperature.

[0029] Specifically, the inner diameter of the annular inner shell 13 is 150 mm, and it forms a 50 mm wide annular duct 14 with the inner diameter of the burner shell 1 of 200 mm; there are three spiral air guide belts 15 with a pitch of 150 mm and a clockwise rotation direction. It can be understood that the setting direction of the air guide hole 12 is the same as the rotation direction of the spiral air guide belt 15; the diverter ring 16 is an annular plate with a thickness of 5 mm, which is used to guide 20-30% of the combustion-supporting air into the air guide hole 12 to form primary air, and 70-80% into the duct to form secondary air.

[0030] The tertiary air structure includes a porous cooling ring cavity 17, which is an annular cavity on the outer periphery of the outlet end 2 of the burner shell 1. It is connected to the combustion air inlet pipe 9 through the air inlet pipe 19. A micro-spray hole 18 with a radial outward inclination of 15° is provided on the side facing the furnace, that is, the angle between the axis of the micro-spray hole 18 and the axis of the burner is 15°, and it is inclined in the direction away from the center of the burner; ensuring that the ejected tertiary air can cover the outer area of ​​the flame tail (the area prone to high temperature in traditional burners); the cavity is slidably connected to the burner shell 1 through an axial slide rail 20, and the drive mechanism is located in the normal temperature zone of the outer wall of the burner shell 1.

[0031] The micro-nozzle 18 is radially tilted outward by 15 degrees, so that the tertiary air can accurately cover the high-temperature area outside the flame tail. In traditional burners, this area is the area most likely to generate thermal nitric oxide. The high-speed jet has a flow rate of >80m / s and reduces the local temperature to below 1300℃ through forced convection, making the temperature lower than the threshold for nitrogen oxide formation.

[0032] By adjusting the axial position of the porous cooling ring cavity 17 through the driving mechanism, it can adapt to the flame shape under different loads. For example, when the load is low, the flame is short and the cavity moves toward the inside of the furnace; when the load is high, the flame is long and the cavity moves toward the burner end, ensuring that the cooling zone always matches the high-temperature zone to avoid overcooling or insufficient cooling.

[0033] The porous cooling ring cavity 17 has an outer diameter of 220mm and a width of 50mm. It contains 36 micro-spray holes, each 2mm in diameter and tilted radially outward at 15°. The air inlet pipe 19 has a diameter of 30mm, and the tertiary air volume accounts for 15-20% of the total combustion-supporting air volume. The axial slide rail 20 has a travel range of 0-100mm, and the drive mechanism uses a magnetically coupled stepper motor with a control accuracy of ±1mm. The stepper motor drives the porous cooling ring cavity 17 axially by rotating the nut through a screw. The screw is arranged along the axis of the burner housing 1, with one end fixed to the inner wall of the burner housing 1 away from the furnace via a bearing seat, while the other end is suspended in the air, not contacting the furnace. The nut is mounted on the porous cooling ring cavity 17 and meshes with the screw. When the driven magnetic ring rotates, the nut moves axially along the screw, driving the porous cooling ring cavity 17 to move synchronously. The axial slide rail 20 is provided with three parallel T-shaped tracks along the axial direction on the wall of the burner housing 1 and is evenly distributed circumferentially. Three T-shaped sliders are welded to the outer side of the porous cooling ring cavity 17. The sliders are embedded in the T-shaped grooves to limit the rotational freedom of the cooling ring cavity and only allow directional movement to be achieved by sliding in the axial direction in conjunction with the screw nut pair.

[0034] The hierarchical collaborative design of this embodiment forms a stepped regulation of "mixing-temperature control-cooling" through primary air swirl premixing, secondary air swirl wrapping, and tertiary air targeted cooling, breaking through the limitation of the single air path of the traditional burner; the axial adjustment of the tertiary air and the flow distribution of the secondary air enable the burner to adapt to different fuels and loads, solving the problem of poor adaptability of traditional burners.

[0035] Example 3: As an improvement to the central jet tube 7, a reflux ejection structure is provided on the central jet tube 7. This structure includes a Venturi tube portion 21 disposed within the central jet tube 7. The Venturi tube portion 21 is located at the radial jet nozzle 5. A diversion tube 22 is provided at the narrow portion of the Venturi tube, radially extending through the fuel pipe 3. The diversion tube 22 is located on the side of the flame stabilizing disk 6 facing the outlet end 2. The diversion tube 22 has multiple diversion holes 23 on the side facing the outlet end 2. This embodiment utilizes the throttling effect of the Venturi tube and the directional ejection of the diversion tube 22 to achieve efficient utilization of the reflux flue gas near the flame stabilizing disk 6.

[0036] The venturi tube portion 21 is arranged in the central jet tube 7. When the air in the central jet tube 7 flows through the narrow portion, the flow velocity increases sharply, forming a local low-pressure area, which provides power for the drainage tube 22 to draw out the smoke without the need for an additional drive device.

[0037] The draft tube 22 radially passes through the fuel pipe 3. One end connects to the narrow section of the Venturi tube, and the other extends to the side of the flame stabilization disk 6 facing the outlet end 2. This is the low-pressure area of ​​the flame stabilization disk 6 near the furnace. The side of the draft tube 22 facing the outlet end 2 is equipped with multiple draft holes 23. The low-pressure area created by the flame stabilization disk 6 draws back the high-temperature flue gas from the furnace. This recirculating flue gas enters the draft tube 22 through the draft holes 23. Under the suction of the low-pressure area at the narrow section of the Venturi tube, the flue gas flows through the draft tube 22 into the central jet tube 7, where it mixes with the air within the tube and is ejected from the end of the central jet tube 7, ultimately mixing with the fuel ejected from the radial jet nozzle 5. The introduction of the recirculating flue gas reduces the oxygen concentration in the initial mixing zone (inert components in the flue gas, such as CO2 and N2, dilute the oxygen), suppressing localized intense combustion and thereby reducing the formation of nitrogen oxides. Furthermore, the high-temperature flue gas provides preheating, promoting combustion efficiency, thereby enhancing mixing and reducing nitrogen oxides.

[0038] Specifically, the drainage tube 22 is a round tube with a diameter of 4 mm, which passes through the fuel pipe 3 radially and is welded to the narrow part of the venturi tube; the drainage tube 22 extends to 10 mm on the side of the flame stabilizing disk 6 facing the outlet end 2, and four drainage holes 23 with a diameter of 1.5 mm are opened on the side of the tube body facing the outlet end 2. The drainage tube 22 is arranged between two adjacent radial jet nozzles 5.

[0039] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A graded air control low nitrogen combustion jet burner structure, characterized in that: The invention comprises a burner shell, which is in the shape of a circular tube with two ends open, one end being an inlet end and the other end being an outlet end; a fuel pipe is coaxially provided through the burner shell, the fuel pipe is set as a blind end at the outlet end, and a plurality of radial jet nozzles arranged radially are connected to the side of the fuel pipe at the outlet end, the radial jet nozzle is provided with a flame stabilizing disk on the side away from the outlet end, and a flow gap is provided between the radial jet nozzle and the burner shell, so that the fuel and the combustion-supporting air cross-jet within the flow gap to form a mixed gas; the fuel pipe is provided with a central jet pipe in its blind end, the air inlet of the central jet pipe radially passes through the fuel pipe upstream of the flame stabilizing disk and is arranged toward the inlet end, and its air outlet passes through the blind end to form a jet nozzle; the burner shell is provided with a combustion-supporting air inlet pipe on the side close to the inlet end.

2. The staged air control low nitrogen combustion jet burner structure according to claim 1 is characterized in that: It also includes a graded air intake system for graded regulation of the combustion-supporting air. The graded air intake system includes a primary air structure, a secondary air structure, and a tertiary air structure. The combustion-supporting air is divided into primary air, secondary air, and tertiary air. The primary air is initially mixed with the fuel, the secondary air suppresses the combustion intensity, and the tertiary air accurately cools down.

3. The staged air control low nitrogen combustion jet burner structure according to claim 2 is characterized in that: The primary air structure includes an annular premixing chamber, which is arranged in an annular flow gap. The annular premixing chamber has an outlet on one side facing the outlet end and forms an annular outlet. The radial jet nozzle is connected to the inner ring of the annular premixing chamber; the outer ring of the annular premixing chamber is circumferentially connected and a plurality of air guide holes are arranged. The air guide holes enter the radial jet nozzle along the tangential direction. The air guide holes form a rotating airflow in the annular premixing chamber, forming a rotating cross jet with the radially injected fuel, and extending the mixing path under the rotating motion.

4. The staged air control low nitrogen combustion jet burner structure according to claim 3 is characterized in that: The secondary air structure includes an annular inner shell arranged on the outer periphery of the annular premixing chamber, and an annular duct is formed between the annular inner shell and the burner shell. The air guide hole passes through the annular inner shell and is connected to the annular duct. The annular duct enters the annular premixing chamber from the air guide hole to form primary air, and is ejected through the annular duct to form secondary air.

5. The staged air control low nitrogen combustion jet burner structure according to claim 4 is characterized in that: A spiral air guide belt is provided in the annular duct, and the spiral air guide belt is multiple and wound in the same direction; a diverter ring is provided on the annular inner shell, and the diverter ring is arranged downstream of the air guide hole inlet.

6. The staged air control low nitrogen combustion jet burner structure according to claim 4 is characterized in that: The tertiary air structure includes a porous cooling ring cavity, which is an annular cavity arranged on the outer periphery of the outlet end of the burner shell. The porous cooling ring cavity has a number of micro spray holes evenly distributed along the circumference toward the furnace side. The porous cooling ring cavity is connected to the combustion air inlet pipe through the air inlet pipe.

7. The staged air control low nitrogen combustion jet burner structure according to claim 6 is characterized in that: The porous cooling ring cavity is adjustable in the axial direction of the burner shell. The porous cooling ring cavity is slidably connected to the burner shell through an axial slide rail. A driving mechanism of the porous cooling ring cavity is arranged in the normal temperature zone of the outer wall of the burner shell.

8. The staged air control low nitrogen combustion jet burner structure according to claim 6 is characterized in that: The micro-spray holes are arranged to be inclined 15 degrees outward in the radial direction so that the tertiary air covers the high-temperature area outside the flame tail.

9. The staged air control low nitrogen combustion jet burner structure according to claim 6 is characterized in that: The central jet tube is provided with a reflux injection structure, which includes a Venturi tube portion arranged in the central jet tube, the Venturi tube portion is located at the radial jet nozzle, and the narrow part of the Venturi tube is provided with a drainage tube radially passing through the fuel pipe. The drainage tube is located on the side of the flame stabilizing disk facing the outlet end, and the drainage tube is provided with multiple drainage holes on the side facing the outlet end.

Images