CN118347003A - A low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions and a combustion method thereof - Google Patents

Abstract

The present invention discloses a low-nitrogen burner and a combustion method thereof suitable for mixed combustion of waste gas and waste liquid under various working conditions. The burner includes a primary combustion-supporting air box; a precombustion chamber located below the primary combustion-supporting air box; a first waste gas header connected between the primary combustion-supporting air box and the precombustion chamber, the primary combustion-supporting air box includes two primary air distribution ducts, namely a swirl air duct and a direct air duct, the swirl air duct is provided with a swirl wind regulating component for regulating the swirl intensity of the swirl wind, and a primary air and swirl wind ratio regulating component; a second waste gas header, arranged outside the middle of the precombustion chamber; a waste liquid and gas integrated spray gun, installed at the central axis position inside the primary combustion-supporting air box; an incinerator, located below the precombustion chamber; and a secondary air duct, arranged outside the precombustion chamber. The burner of the present invention selects different waste gas headers for waste gas and waste liquid with different characteristics, and can still maintain a good combustion state when the waste gas and waste liquid flow fluctuates.

Description

A low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions and a combustion method thereof

Technical Field

The present invention relates to the technical field of burners, and in particular to a low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions and a combustion method thereof.

Background technique

In recent years, with the steady development of the chemical industry and the improvement of environmental protection requirements, the incineration of waste gas and waste liquid in various chemical processes has become an environmental protection hotspot and problem. Incineration is a technology with a high removal rate for waste gas and waste liquid. Compared with other technologies, it can not only cleanly treat waste gas and waste liquid, but the high-temperature flue gas from incineration also has very superior waste heat recovery value.

In chemical production, waste gas and waste liquid generated in various process links need to be burned and treated, but the waste gas and waste liquid generated by various devices in the chemical process are of many types and have large differences in composition. In addition, the flow rate and composition of the device vary greatly under various working conditions. The existing burner adjustment load ratio, that is, the minimum design flow rate: the maximum design flow rate is limited, generally 1:10. The ability of the burner to treat waste gas and waste liquid is usually designed according to the maximum flow rate. The performance curve of the pre-designed waste gas and waste liquid spray gun has a minimum working flow rate within the working range, which usually cannot meet the minimum flow rate requirements of the device. In addition, the calorific value of waste gas and waste liquid fluctuates greatly, and traditional waste gas and waste liquid spraying will cause licking or flameout, resulting in a short burner life and unstable flames. In addition, due to incomplete combustion, nitrogen oxide emissions often exceed the standard.

Summary of the invention

In view of the above technical problems, the present invention proposes a low-nitrogen burner with reasonable design, wide range of load conditions, flexible load adjustment, and adaptability to mixed combustion of various waste gases and waste liquids under various working conditions. The burner adopts a modular structure, and different modules are selected for waste gases and waste liquids with different characteristics, so that a good combustion state can be maintained even when the waste gas and waste liquid flow fluctuates.

In order to achieve the above technical objectives, the present invention adopts the following technical means:

A low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions, including:

A primary combustion-supporting air box, a first exhaust gas header, a pre-combustion chamber and an incinerator, wherein the primary combustion-supporting air box includes two primary air distribution ducts, namely a swirl air duct and a direct air duct, and the swirl air duct is provided with a swirl air regulating component for regulating the swirl strength of the swirl air;

The first exhaust gas header is provided with a central chamber connected to the cyclone air duct, and a plurality of first exhaust gas header units arranged around the outside of the central chamber and arranged in sequence along the height direction of the burner. The plurality of first exhaust gas header units are independent of each other, and each of the first exhaust gas header units passes exhaust gas into the pre-combustion chamber through an exhaust gas nozzle;

The second exhaust gas header is an annular box body arranged outside the middle of the pre-combustion chamber, and the wall of the pre-combustion chamber is provided with a second exhaust gas channel connecting the second exhaust gas header with the interior of the pre-combustion chamber;

A waste liquid and gas integrated spray gun, installed at the central axis position inside the primary combustion-supporting air box, used for introducing waste liquid and gas into the pre-combustion chamber;

The secondary air duct is arranged outside the pre-combustion chamber and below the second exhaust gas header, and the secondary air enters the incinerator through the secondary air duct.

A DC air duct with upper and lower openings is vertically arranged at the inner center of the primary combustion-supporting air wind box, and both sides of the DC air duct are fixedly connected to the inner wall of the primary combustion-supporting air wind box through internal support members, and the lower end of the DC air duct extends to the junction of the primary combustion-supporting air wind box and the pre-combustion chamber;

A primary air-to-DC air ratio adjustment cylinder is coaxially plugged into the DC air cylinder and is located at the upper end of the DC air cylinder. The upper end of the primary air-to-DC air ratio adjustment cylinder passes through the upper panel of the primary combustion-supporting air box through an adjustment rod and is connected to the adjustment handle. After the connection, an adjustment gap is left between the upper end of the primary air-to-DC air ratio adjustment cylinder and the upper panel of the primary combustion-supporting air box.

A swirl air duct ring cover, the inner ring of which is fixedly connected to the outer wall of the DC air duct;

A cyclone air cylinder is coaxially sleeved on the outside of the DC air cylinder and is located below the cyclone air channel ring cover, so that an annular cyclone channel is formed between the cyclone air cylinder and the DC air cylinder;

A swirl sheet is arranged between the swirl air duct ring cover and the swirl air cylinder, wherein the swirl sheet comprises a plurality of swirl sheets, and the plurality of swirl sheets are evenly arranged along the circumference of the DC air cylinder;

Part of the primary air passes through the upper space of the swirl air duct ring cover, the adjustment gap and the primary air/DC air ratio adjustment cylinder in sequence, enters the DC air duct to form the DC air duct, and enters the pre-combustion chamber;

Another part of the primary air passes through the interval space between the swirl plates to form a swirl, and then passes through the annular swirl channel and the central chamber in sequence to enter the pre-combustion chamber.

The swirl wind regulating component comprises:

A swirl blade angle adjustment handle is provided on the upper panel surface of the primary combustion-supporting air box;

A swirl blade angle adjustment driving shaft, one end of which is connected to the swirl blade angle adjustment handle, and the other end of which is arranged vertically downward and connected to one of the plurality of swirl blades;

Each of the swirl plates is fixedly connected to a vertically arranged swirl plate angle adjustment driven shaft.

The swirl air duct ring cover is provided with an arc-shaped through groove corresponding to each swirl plate for the upper end of the swirl plate angle adjustment driven shaft to pass through;

The swirl plate adjustment rotating disk is coaxially sleeved on the outside of the DC air duct and is located on the upper surface of the swirl air duct ring cover. The swirl plate adjustment rotating disk is provided with a long hole corresponding to each swirl plate angle adjustment driven shaft. When the swirl plate angle adjustment driven shaft rotates, the swirl plate adjustment rotating disk itself can rotate relative to the DC air duct, thereby driving all the swirl plates to rotate at the same angle.

The waste liquid and gas integrated spray gun includes:

A central tube spray gun, a first sleeve and a second sleeve, wherein:

The central tube spray gun is used to introduce waste liquid;

The annular compartment between the first sleeve and the central tube spray gun is used to introduce compressed air or steam for atomizing the waste liquid;

The annular compartment between the first sleeve and the second sleeve is used for introducing fuel gas.

The second exhaust gas passage between the second exhaust gas header and the pre-combustion chamber is arranged in a tangential circle.

The primary combustion-supporting air box and the first exhaust gas header, and the first exhaust gas header and the pre-combustion chamber are respectively connected through a first flange.

The plurality of first exhaust gas header units are connected via a second flange.

Each of the first exhaust gas header units is connected to the pre-combustion chamber via a plurality of exhaust gas nozzles to spray the exhaust gas into the pre-combustion chamber. The plurality of exhaust gas nozzles are evenly arranged along the circumference of the first exhaust gas header.

The inner cavity of the pre-combustion chamber is composed of a first diameter expansion section, a straight tube section and a second diameter expansion section from top to bottom.

The combustion method of the low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions,

Waste liquid and gas are sprayed into the pre-combustion chamber from the waste liquid and gas integrated spray gun;

The primary air entering the burner is divided into swirl air and direct current air. The ratio of swirl air to direct current air is adjusted by the adjusting rod. The distance between the primary air and direct current air ratio adjusting cylinder and the burner panel is adjusted by the adjusting rod to achieve the change of flow rate.

The swirl intensity of the primary air is changed by the swirl wind regulating component to control the premixed combustion intensity of the burner to adapt to multiple working conditions;

The first exhaust gas with a flow rate fluctuation range of 1:50 and a calorific value fluctuation range of 3000-60000 kJ/Nm3 is sprayed into the flame root in the pre-combustion chamber through the first exhaust gas header and the exhaust gas nozzle to stabilize and support flame combustion; the first exhaust gas header includes a plurality of independent first exhaust gas header units, which can simultaneously burn a plurality of first exhaust gases according to demand;

The second exhaust gas with flow fluctuation range: 1:50 and calorific value fluctuation range: 0-30000kJ/Nm3 enters the flame middle end in the pre-combustion chamber through the second exhaust gas header and the second exhaust gas channel. The flame preheats the exhaust gas, and the second exhaust gas does not affect the flame stability. The gas channel is arranged in a tangential circle, which enhances premixing and ensures full combustion.

The combustion is divided into two stages. The first stage is in the pre-combustion chamber, which forms a high-temperature, oxygen-deficient combustion environment to inhibit the production of nitrogen oxides. The second stage is in the incinerator, where the secondary air allows the combustion products of the first stage to fully react with the oxygen content of the flue gas at 1300~1500℃ and the oxygen content of the flue gas is not less than 6%, achieving a waste gas and waste liquid removal rate of 99.9%.

(1) The present invention provides a low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions. The co-burning gas spray gun is designed to be integrated with the waste liquid spray gun. The waste liquid is sprayed into the furnace from the central tube, and the waste liquid atomizing air is sent from the central sleeve to the gun head to atomize the waste liquid. The gas is sent from the sleeve of the atomizing air pipe and the gas hole of the sleeve gun head into the furnace, thereby reducing the space occupied by the burner panel. When there are multiple waste liquids and the waste liquid spray gun is added, the burner panel design is more compact.

(2) In the burner provided by the present invention, the primary air entering the burner is divided into two stages of air distribution: swirl air and direct current air. The ratio of swirl air to direct current air can be adjusted by an adjustment rod, and the ratio of direct current air to swirl air can be changed by adjusting the height of the adjustment rod to change the distance between the primary air direct current air ratio adjustment tube and the burner panel to achieve the change of flow rate.

(3) The burner provided by the present invention can achieve the swirl intensity of the primary air by adjusting the angle of the swirl blade. The swirl blade angle adjustment handle on the burner panel (adjustment angle range 0~60°) can be adjusted to drive the swirl blade angle adjustment active shaft to rotate, and the swirl blade connected to the swirl blade angle adjustment active shaft rotates, and the swirl blade angle adjustment driven shaft on the swirl blade rotates accordingly. The swirl air duct ring cover has a designed fan-shaped hole that can adapt to the rotation angle of the swirl blade angle adjustment driven shaft; the swirl blade adjustment rotating disk has an oblong hole that adapts to the rotation of the swirl blade angle adjustment driven shaft. At the same time, the swirl blade adjustment rotating disk itself is also rotated on the outside of the DC air duct, thereby driving all the swirl blades to rotate together. Thereby, when the swirl blade angle adjustment handle is adjusted, all the swirl blades inside the burner rotate a certain angle. The premixed combustion intensity of the burner can be controlled to adapt to multiple working conditions.

(4) In the burner provided by the present invention, the DC air enters the DC air channel through the air distribution holes at the upper end of the DC air duct, thereby ensuring the uniformity of the DC air entering the burner flame, ensuring the rigidity of the flame, and ensuring that the flame does not burn unevenly or lick when the calorific value of various exhaust gases fluctuates.

(5) The burner provided by the present invention has a flow fluctuation range of 1:50 and a calorific value fluctuation range of 8000-60000 kJ/Nm3. The first exhaust gas is sprayed into the flame root in the pre-combustion chamber through the first exhaust gas header and the exhaust gas nozzle to stabilize and support the flame combustion, and enters the pre-combustion chamber through 20-50 nozzles evenly distributed circumferentially. The dispersed combustion technology is used to reduce the flame temperature and the generation of temperature-type nitrogen oxides. The nozzle has a small structural resistance drop, which is suitable for large calorific value fluctuations and load regulation ratio conditions. Considering that there are many types of first exhaust gases, some factories have more than one hundred types, and some exhaust gases that can be merged are merged, while some exhaust gases cannot be merged. The merger will cause reactions or explosions. Generally, there are still multiple streams after the merger. Therefore, the first exhaust gas header of the present invention includes multiple independent first exhaust gas header units to achieve simultaneous processing of multiple first exhaust gases.

(6) The burner provided by the present invention has a flow fluctuation range of 1:50 and a calorific value fluctuation range of 0-30000 kJ/Nm3. The second exhaust gas enters the pre-combustion chamber through the second exhaust gas channel, and the air channel is arranged in a tangential circle, so the combustion is sufficient. At the same time, because the resistance drop in the air channel is lower than that of the nozzle structure with fine holes, the resistance drop of the air channel can be less than 1 kPa, while the nozzle structure with fine holes is usually greater than 10 kPa. Such a low resistance drop structure is suitable for exhaust gases with variable working conditions, such as working conditions with large calorific value fluctuations and large flow regulation ratios.

(7) The burner provided by the present invention is equipped with a pre-combustion chamber. The inner wall of the pre-combustion chamber has a refractory lining, which is not only refractory but also a heat storage body. When the operating conditions of the first exhaust gas, the second exhaust gas and the waste liquid fluctuate violently, the flame will be unstable. The presence of the high-temperature heat storage body has the effect of preheating and stabilizing the combustion of the exhaust gas and the waste liquid, thereby strengthening the overall burner to resist the instability caused by the fluctuation of the operating conditions.

(8) The burner provided by the present invention has air distribution divided into primary air and secondary air, which divides the combustion into two stages. The first stage is in the pre-combustion chamber, forming a high-temperature oxygen-deficient combustion environment to suppress the generation of nitrogen oxides; the second stage is in the incinerator, and the secondary air allows the combustion products of the first stage to fully react at a relatively low temperature (1100°C) and excess oxygen (the oxygen content of the flue gas is not less than 6%), achieving a waste gas and waste liquid removal rate of 99.9%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic structural diagram of a low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions of the present invention;

Among them, 1. Integrated spray gun for waste liquid and gas; 2. Reserved hole for ignition gun; 3. Adjustment rod; 4. Swirl blade angle adjustment handle; 5. Swirl blade angle adjustment active shaft; 6. Swirl blade; 7. Primary combustion air bellows; 8. First exhaust gas header unit A; 9. First exhaust gas header unit B; 10. Exhaust gas nozzle A; 11. Exhaust gas nozzle B; 12. Reserved hole for flame detector; 13. Primary air DC air ratio adjustment cylinder; 14. Swirl blade adjustment rotating disk; 15. Swirl air duct ring cover; 16. Swirl blade angle adjustment driven shaft; 17. DC air duct; 18. Swirl air duct;

FIG2 is a schematic diagram of gas flow in a low-nitrogen burner structure suitable for mixed combustion of waste gas and waste liquid under various working conditions of the present invention;

19. pre-combustion chamber; 20. second exhaust gas header; 21. second exhaust gas channel; 22. secondary air duct;

FIG. 3 is a schematic diagram of the structure of the swirl wind regulating assembly of the present invention.

Detailed ways

The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, modifications of various equivalent forms of the present invention by those skilled in the art all fall within the scope defined in this application.

As shown in FIG1 , a low nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions is characterized in that it includes a primary combustion-supporting air box 7, a waste liquid and gas integrated spray gun 1 is installed at the central axis position inside the primary combustion-supporting air box 7, an ignition gun reserved hole 2 is installed on the panel of the primary combustion-supporting air box 7, a flame detector reserved hole 12 is installed on the panel of the primary combustion-supporting air box 7, and an adjustment rod 3 is installed on the panel of the primary combustion-supporting air box 7.

A DC air duct 17 with upper and lower openings is vertically arranged at the inner center of the primary combustion-supporting air box. Both sides of the DC air duct 17 are fixedly connected to the inner wall of the primary combustion-supporting air box 7 through internal supports. The lower end of the DC air duct 17 extends to the junction of the primary combustion-supporting air box and the pre-combustion chamber, and the upper end is connected to the panel of the primary combustion-supporting air box 7. The DC air flow channel area is a perforated plate.

The primary air/DC air ratio adjustment cylinder 13 is coaxially inserted into the DC air cylinder 17 and is located at the upper end of the DC air cylinder 17. The upper end of the primary air/DC air ratio adjustment cylinder 13 is connected to the upper panel of the primary combustion-supporting air box 7 through the adjustment rod 3, and after the connection, an adjustment gap is left between the upper end of the primary air/DC air ratio adjustment cylinder 13 and the upper panel of the primary combustion-supporting air box 7.

The inner ring of the swirl air duct ring cover 15 is fixedly connected to the outer wall of the DC air cylinder 17;

The cyclone air cylinder 18 is coaxially sleeved on the outside of the DC air cylinder 17 and is located below the cyclone air channel ring cover 15. An annular cyclone channel is formed between the cyclone air cylinder 18 and the DC air cylinder 17.

The swirl blade 6 is arranged between the swirl air duct ring cover 15 and the swirl air cylinder 18. The swirl blade 6 includes a plurality of swirl blades 6, and the plurality of swirl blades 6 are evenly arranged along the circumference of the DC air cylinder 17;

The primary air passes through the upper space of the swirl air duct ring cover 15, the adjustment gap and the primary air/DC air ratio adjustment cylinder 13 in sequence and enters the DC air cylinder 17 to form the DC air duct, and enters the pre-combustion chamber.

Another part of the primary air passes through the interval space between the swirl blades 6 to form a swirl, and then passes through the annular cyclone channel and the central cavity in sequence to enter the pre-combustion chamber 19.

The swirl wind regulating component comprises:

The swirl blade angle adjustment handle 4 is arranged on the upper panel surface of the primary combustion air box 7;

A swirl blade angle adjustment driving shaft 5, one end of which is connected to the swirl blade angle adjustment handle 4, and the other end of which is arranged vertically downward and connected to one of the plurality of swirl blades 6;

Each of the swirl plates 6 is fixedly connected to a vertically arranged swirl plate angle adjustment driven shaft 16.

The swirl air duct ring cover 15 is provided with an arc-shaped through slot corresponding to each swirl plate 6 for the upper end of the swirl plate angle adjustment driven shaft 16 to pass through;

The swirl plate adjusting rotating disk 14 is coaxially sleeved on the outside of the DC air cylinder 17 and is located on the upper surface of the swirl air duct ring cover 15. The swirl plate adjusting rotating disk 14 is provided with a long hole corresponding to each swirl plate angle adjustment driven shaft 16. When the swirl plate angle adjustment driven shaft 16 rotates, the swirl plate adjusting rotating disk 14 itself can rotate relative to the DC air cylinder 17, thereby driving all the swirl plates 6 to rotate at the same angle.

As a preferred embodiment of the present invention, two first exhaust gas collecting box units are connected between the primary combustion air box 7 and the pre-combustion chamber 19. The two first exhaust gas collecting box units are independent of each other and respectively pass the exhaust gas into the pre-combustion chamber 19 through the exhaust gas nozzles.

The swirl air duct ring cover 15 is vertically welded to the DC air cylinder 17 , and the swirl air cylinder 18 is connected to the swirl air duct ring cover 15 via the swirl sheet angle adjustment driving shaft 5 .

The burner head of the present invention is provided with waste liquid and gas to provide the main flame, and the rear part is designed with a pre-combustion chamber, which is a high-temperature oxygen-poor environment, providing space for the waste liquid burner and space for waste gas mixing and heating. The burner is equipped with secondary air to further assist the combustion of the flame.

The waste liquid spray gun adopts gas and waste liquid integrated type. The outer sleeve of the waste liquid spray gun is the waste liquid atomization medium channel, and the outer sleeve of the waste liquid atomization medium channel is the gas spray gun. When the flow rate and calorific value of the waste liquid fluctuate, the pressure and flow rate of the gas are stable, the rigidity of the mixed combustion flame is good, and the combustion is stable.

The exhaust gas adopts the form of air intake manifold connected to group pipes, the exhaust gas nozzle pressure drop is small, the exhaust gas enters the pre-combustion chamber for mixing and preheating, and the flame is strengthened. When the exhaust gas flow and calorific value change, the overall flame of the burner is not affected and the combustion is stable.

The waste liquid enters the burner through the integrated waste liquid and gas spray gun, and the waste liquid enters the central tube spray gun. The first sleeve of the outer layer of the waste liquid gun structure is used to atomize the compressed air or steam of the waste liquid, and the second sleeve of the outer layer of the first sleeve is a gas gun used for auxiliary combustion.

The combustion method of the low-nitrogen burner applicable to mixed combustion of waste gas and waste liquid under various working conditions of the present invention is that the burner is composed of a combination of multiple modules, and the matching design can be selected according to the calorific value characteristics and flow characteristics of the actual waste gas and waste liquid; the burner is staged combustion, and the air distribution of the first-stage combustion is divided into swirl and direct flow, and the air distribution ratio of the system can be flexibly adjusted to achieve low-nitrogen combustion, specifically:

Waste liquid and gas are sprayed into the pre-combustion chamber from the waste liquid and gas integrated spray gun;

The primary air entering the burner is divided into swirl air and direct current air. The ratio of swirl air to direct current air is adjusted by the adjusting rod. The distance between the primary air and direct current air ratio adjusting cylinder and the burner panel is adjusted by the adjusting rod to achieve the change of flow rate.

The swirl intensity of the primary air is changed by the swirl wind regulating component to control the premixed combustion intensity of the burner to adapt to multiple working conditions;

The first exhaust gas header box includes a plurality of mutually independent first exhaust gas header box units;

Flow rate fluctuation range: 1:50, calorific value fluctuation range: 8000-60000kJ/Nm3. The first exhaust gas is sprayed into the flame root in the pre-combustion chamber through the first exhaust gas header and the exhaust gas nozzle to stabilize and support the flame combustion, and enters the pre-combustion chamber through 20-50 nozzles evenly distributed circumferentially. The dispersed combustion technology is used to reduce the flame temperature and the generation of temperature-type nitrogen oxides.

Flow rate fluctuation range: 1:50, calorific value fluctuation range: 0-30000kJ/Nm3. The second exhaust gas enters the flame middle end in the pre-combustion chamber through the second exhaust gas header and the second exhaust gas channel. The flame preheats the low calorific value exhaust gas. The second exhaust gas will not affect the flame stability. The gas channel is arranged in a tangential circle to enhance premixing and ensure full combustion.

The combustion is divided into two stages. The first stage is in the pre-combustion chamber, which forms a high-temperature, oxygen-deficient combustion environment to inhibit the production of nitrogen oxides. The second stage is in the incinerator, where the secondary air allows the combustion products of the first stage to fully react with the oxygen content of the flue gas at 1100°C and the oxygen content of not less than 6%, achieving a waste gas and waste liquid removal rate of 99.9%.

The primary combustion-supporting air enters the burner through the primary combustion-supporting air wind box; the secondary air enters the incinerator through the secondary air duct (not shown in the figure).

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 principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims (10)

1. A low nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions, including: The primary combustion air box, the first exhaust gas header, the pre-combustion chamber and the incinerator are characterized in that: The primary combustion-supporting air box includes two primary air distribution ducts, namely a swirl air duct and a direct air duct, and the swirl air duct is provided with a swirl air regulating component for regulating the swirl strength of the swirl air; The first exhaust gas header is provided with a central chamber connected to the cyclone air duct, and a plurality of first exhaust gas header units arranged around the outside of the central chamber and arranged in sequence along the height direction of the burner. The plurality of first exhaust gas header units are independent of each other, and each of the first exhaust gas header units passes exhaust gas into the pre-combustion chamber through an exhaust gas nozzle; The second exhaust gas header is an annular box body arranged outside the middle of the pre-combustion chamber, and the wall of the pre-combustion chamber is provided with a second exhaust gas channel connecting the second exhaust gas header with the interior of the pre-combustion chamber; A waste liquid and gas integrated spray gun, installed at the central axis position inside the primary combustion-supporting air box, used for introducing waste liquid and gas into the pre-combustion chamber; The secondary air duct is arranged outside the pre-combustion chamber and below the second exhaust gas header, and the secondary air enters the incinerator through the secondary air duct. 2. The low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions according to claim 1 is characterized in that: A DC air duct (17) with upper and lower openings is vertically arranged at the inner center of the primary combustion-supporting air wind box, and both sides of the DC air duct (17) are fixedly connected to the inner wall of the primary combustion-supporting air wind box through internal support members, and the lower end of the DC air duct (17) extends to the junction of the primary combustion-supporting air wind box and the pre-combustion chamber; A primary air/DC air ratio adjustment cylinder is coaxially plugged into the DC air cylinder (17) and is located at the upper end of the DC air cylinder (17); the upper end of the primary air/DC air ratio adjustment cylinder passes through the upper panel of the primary combustion-supporting air box and is connected to the swirl blade angle adjustment handle via an adjustment rod; and after the connection, an adjustment gap is left between the upper end of the primary air/DC air ratio adjustment cylinder and the upper panel of the primary combustion-supporting air box; A swirl air duct ring cover, the inner ring of which is fixedly connected to the outer wall of the DC air cylinder (17); A cyclone air cylinder (18) is coaxially sleeved on the outside of the DC air cylinder (17) and is located below the cyclone air channel ring cover, so that an annular cyclone channel is formed between the cyclone air cylinder (18) and the DC air cylinder (17); A swirl sheet arranged between the swirl air duct ring cover and the swirl air cylinder (18), the swirl sheet comprising a plurality of swirl sheets, the plurality of swirl sheets being evenly arranged along the circumference of the DC air cylinder (17); Part of the primary air passes through the upper space of the swirl air duct ring cover, the adjustment gap and the primary air/DC air ratio adjustment cylinder in sequence, enters the DC air duct (17) to form the DC air duct, and enters the pre-combustion chamber; Another part of the primary air passes through the interval space between the swirl plates to form a swirl, and then passes through the annular swirl channel and the central chamber in sequence to enter the pre-combustion chamber. 3. The low-nitrogen burner applicable to mixed combustion of waste gas and waste liquid under various working conditions according to claim 2, characterized in that the swirl wind regulating component comprises: The swirl blade angle swirl blade angle adjustment handle is arranged on the upper panel surface of the primary combustion air bellows; A swirl blade angle adjustment driving shaft, one end of which is connected to the swirl blade angle adjustment handle, and the other end of which is arranged vertically downward and connected to one of the plurality of swirl blades; Each of the swirl plates is fixedly connected to a vertically arranged swirl plate angle adjustment driven shaft. The swirl air duct ring cover is provided with an arc-shaped through groove corresponding to each swirl plate for the upper end of the swirl plate angle adjustment driven shaft to pass through; The swirl plate adjustment rotating disk is coaxially sleeved on the outside of the DC air cylinder (17) and is located on the upper surface of the swirl air duct ring cover. The swirl plate adjustment rotating disk is provided with a long hole corresponding to each swirl plate angle adjustment driven shaft. When the swirl plate angle adjustment driven shaft rotates, the swirl plate adjustment rotating disk itself can rotate relative to the DC air cylinder (17), thereby driving all the swirl plates to rotate at the same angle. 4. The low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions according to claim 1 is characterized in that: The waste liquid and gas integrated spray gun includes: A central tube spray gun, a first sleeve and a second sleeve, wherein: The central tube spray gun is used to introduce waste liquid; The annular compartment between the first sleeve and the central tube spray gun is used to introduce compressed air or steam for atomizing the waste liquid; The annular compartment between the first sleeve and the second sleeve is used for introducing fuel gas. 5. The low nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions according to claim 1 is characterized in that: The second exhaust gas passage between the second exhaust gas header and the pre-combustion chamber is arranged in a tangential circle. 6. The low nitrogen burner applicable to mixed combustion of waste gas and waste liquid under various working conditions according to claim 1 is characterized in that: The primary combustion-supporting air box and the first exhaust gas header, and the first exhaust gas header and the pre-combustion chamber are respectively connected through a first flange. 7. The low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions according to claim 1 is characterized in that a plurality of the first waste gas header units are connected by a second flange. 8. According to claim 1, the low-nitrogen burner suitable for mixed combustion of exhaust gases and waste liquids under various working conditions is characterized in that each of the first exhaust gas header units is connected to the pre-combustion chamber through a plurality of exhaust gas nozzles to spray the exhaust gas into the pre-combustion chamber, and the plurality of exhaust gas nozzles are evenly arranged along the circumference of the first exhaust gas header. 9. The low-nitrogen burner suitable for mixed combustion of waste gas and waste liquid under various working conditions according to claim 1 is characterized in that the inner cavity of the pre-combustion chamber is composed of a first expanded diameter section, a straight cylinder section and a second expanded diameter section from top to bottom. 10. The combustion method of a low-nitrogen burner applicable to mixed combustion of waste gas and waste liquid under various working conditions according to any one of claims 1 to 9, characterized in that: Waste liquid and gas are sprayed into the pre-combustion chamber from the waste liquid and gas integrated spray gun; The primary air entering the burner is divided into swirl air and direct current air. The ratio of swirl air to direct current air is adjusted by the adjusting rod. The distance between the primary air and direct current air ratio adjusting cylinder and the burner panel is adjusted by the adjusting rod to achieve the change of flow rate. The swirl intensity of the primary air is changed by the swirl air regulating component to control the premixed combustion intensity of the burner to adapt to multiple working conditions; The first exhaust gas with a flow rate fluctuation range of 1:50 and a calorific value fluctuation range of 3000-60000 kJ/Nm3 is sprayed into the flame root in the pre-combustion chamber through the first exhaust gas header and the exhaust gas nozzle to stabilize and support flame combustion; the first exhaust gas header includes a plurality of independent first exhaust gas header units, which can simultaneously burn a plurality of first exhaust gases according to demand; The second exhaust gas with flow fluctuation range: 1:50 and calorific value fluctuation range: 0-30000kJ/Nm3 enters the flame middle end in the pre-combustion chamber through the second exhaust gas header and the second exhaust gas channel. The flame preheats the exhaust gas, and the second exhaust gas does not affect the flame stability. The gas channel is arranged in a tangential circle, which enhances premixing and ensures full combustion. The combustion is divided into two stages. The first stage is in the pre-combustion chamber, which forms a high-temperature, oxygen-deficient combustion environment to inhibit the production of nitrogen oxides. The second stage is in the incinerator, where the secondary air allows the combustion products of the first stage to fully react with the oxygen content of the flue gas at 1300~1500℃ and the oxygen content of the flue gas is not less than 6%, achieving a waste gas and waste liquid removal rate of 99.9%.