CN112923361B

CN112923361B - Direct-current burner for burning high-temperature raw gas

Info

Publication number: CN112923361B
Application number: CN202110181790.8A
Authority: CN
Inventors: 孙锐; 孟晓晓; 邢春礼; 闫永宏; 孙刘涛; 朱文堃
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2021-02-08
Filing date: 2021-02-08
Publication date: 2024-05-24
Anticipated expiration: 2041-02-08
Also published as: CN112923361A

Abstract

A direct-current burner for burning high-temperature raw gas belongs to the technical field of high-efficiency clean coal combustion. The invention solves the problems that the low NOx burner in the prior art is not suitable for the high-efficiency low NOx direct-current combustion of raw coke oven gas and the high-efficiency low NOx direct-current burner of the raw coke oven gas in the prior art is not available, so that the high-efficiency low NOx direct-current burner of the raw coke oven gas cannot be configured for the sectional coupling pulverized coal combustion technology. The invention comprises a central pipe, a raw gas inlet pipeline, a concentrated raw gas pipeline, a primary air distribution pipeline, a light raw gas pipeline, a fire side wall plate, a porous concentration grid, a split grid, a blunt body, a raw gas diffusion ring, a water cooling coil pipe cooling system and a multiple diffusion flame generator; the method is based on the comprehensive cooling technology of the raw gas horizontal gradation, multiple diffusion flame, internal combustion stabilization of blunt body vortex outer boundary layer ignition, fuel-rich combustion, water cooling and air cooling, so as to realize the combustion of the raw gas; the invention is suitable for the sectional coupling pulverized coal combustion of a wide range of coal types.

Description

Direct-current burner for burning high-temperature raw gas

Technical Field

The invention belongs to the technical field of efficient clean coal combustion.

Background

Although various coal burning technologies are developed at home and abroad, the technology is characterized in that the combustion of fuel such as low-volatile anthracite, lean coal, coke and the like which are difficult to burn is realized, and because the physicochemical conditions for realizing high-efficiency cleaning on the same equipment are often mutually restricted, the development of the coal burning technology for realizing stable combustion on fire, high efficiency, low NOx, slag bonding prevention, high-temperature corrosion, fast load response and excellent low load performance is still challenged.

Aiming at the combustion of fuel such as difficult-to-burn low-volatile anthracite, lean coal and coke, the prior art provides a sectional coupling pulverized coal combustion device and method, based on the theoretical design of pyrolysis, combustion, crushing, gasification, desulfurization, particle sorting, carbon conversion and burnout of different equipment in different stages of coal combustion thermochemical conversion, the structural design of effective coupling of quality, momentum and energy in each stage is implemented by utilizing a new structure in a furnace, a low-temperature pyrolysis section of a preferred double-vortex rapid fluidized bed and a high-temperature carbon conversion section of a pulverized coal furnace are combined, the independent control of each section breaks through the mutual restriction of the physicochemical conditions of high-efficiency clean coal combustion implemented in the same equipment, plays the advantages of each section and overcomes the disadvantages of each section, so that the pulverized coal combustion with stable combustion, high efficiency, low NOx, slagging resistance, high-temperature corrosion resistance and low-load excellent inferior quality performance of coal, particularly difficult-to-combustion coal can be realized simultaneously, and the coal variety adaptability of combustion equipment is expanded. However, in the sectional coupling pulverized coal combustion technology, a high-performance raw gas direct current/cyclone burner is configured for a pulverized coal furnace for implementing carbon conversion and burnout of a high-temperature carbon conversion section so as to effectively couple and combust raw gas generated by a low-temperature section double-vortex fast fluidized bed, so that the sectional coupling pulverized coal combustion can be implemented in reality, and the efficient clean pulverized coal combustion of a wide range of coal types is realized.

The method comprises the steps of carrying out a sectional coupling pulverized coal combustion process in two sections, utilizing a preferable double-vortex rapid fluidized bed in a low-temperature section of less than 980 ℃, independently carrying out drying, pyrolysis, combustion, crushing, gasification, desulfurization and particle sorting on coal with a particle size of less than 10mm, and reforming fuel into raw coke gas by centrifugal fluidization, wherein the raw coke gas is a gas-solid two-phase flow which is produced by the preferable double-vortex rapid fluidized bed in the low-temperature section, has a pressure of less than 3MPa and a temperature of 500-980 ℃, and only contains semicoke and coke particles with a particle size of less than 70 mu m in combustible gas; in the high temperature section of 980 ℃ or more, a direct current/rotational flow raw gas burner needs to be arranged in the pulverized coal furnace, so that the raw gas can be independently and efficiently and cleanly combusted in the pulverized coal furnace, and the pulverized coal combustion with the advantages of wide range of coal types, difficult coal combustion, stable combustion, high efficiency, low NOx, slag bonding prevention, high temperature corrosion prevention, fast load response and excellent low load performance can be finally realized in the sectional coupling pulverized coal combustion process. However, the prior art is not provided with a corresponding raw gas direct-current burner for the sectional coupling pulverized coal combustion technology so as to realize the high-efficiency low-NOx direct-current combustion of the high-temperature carbon conversion section; in the prior art, although the European Union discloses an Injector low NOx high-efficiency hydrogen direct-current burner and a classical absolute ignition stable combustion high-excess air coefficient low NOx fuel direct-current burner, the fuel and the combustion purpose are different, and the fuel and the combustion purpose are not suitable for the raw gas direct-current combustion, in addition, a coal dust direct-current burner is disclosed, the generation of fuel NOx can be effectively inhibited, but the technology for inhibiting the generation of thermal NOx is imperfect; therefore, the existing low NOx direct current burner is not suitable for the high efficiency low NOx direct current combustion of the raw gas due to different fuels and different combustion purposes.

In summary, the problems that the low NOx burner in the prior art is not suitable for high-efficiency low NOx direct current combustion of raw coke oven gas and the high-efficiency low NOx direct current burner of raw coke oven gas in the prior art is not available, so that the raw coke oven gas direct current burner cannot be configured for the sectional coupling pulverized coal combustion technology are solved.

Disclosure of Invention

The invention aims to solve the problems that a low-NOx burner in the prior art is not suitable for high-efficiency low-NOx direct-current combustion of raw gas and the high-efficiency low-NOx raw gas direct-current burner in the prior art is not available, so that the raw gas direct-current burner cannot be configured for a segmented coupling pulverized coal combustion technology.

The first structure of the direct current burner for burning high temperature raw gas is as follows:

the direct-current burner for burning high-temperature raw gas comprises a central tube 1, a raw gas inlet pipeline 2, a concentrated raw gas pipeline 3, a primary air distribution pipeline 4, a light raw gas pipeline 5, a fire side wall plate 6, a porous concentration grid 7, a split grid 8, a blunt body 9, a raw gas diffusion ring 10, a water-cooling coil pipe cooling system 11 and a multiple diffusion flame generator 12; the bottom ends of the central pipe 1, the concentrated raw gas pipeline 3, the primary air distribution pipeline 4 and the light raw gas pipeline 5 are communicated; a No.1 air inlet is arranged on the side wall of the raw gas inlet pipeline 2; the wall surface of the primary air distribution pipeline 4 is provided with a No. 2 air inlet 4-1;

the central tube 1 and the concentrated raw gas pipeline 3 are coaxially arranged from inside to outside in sequence, the bottom ends of the central tube 1 and the concentrated raw gas pipeline 3 are flush, and an annular channel is formed between the central tube 1 and the concentrated raw gas pipeline 3; the bottom end of the thick raw gas pipeline 3 is provided with a raw gas diffusion ring 10, and the first-stage air distribution pipeline 4 is sleeved outside the thick raw gas pipeline 3; the light raw gas pipeline 5 is arranged in an annular channel formed between the thick raw gas pipeline 3 and the first-stage air distribution pipeline 4, the light raw gas pipeline 5 is close to the back fire side of the boiler, and the axis of the light raw gas pipeline 5 is parallel to the axis of the first-stage air distribution pipeline 4; the top end of the raw gas pipeline 5 is communicated with the raw gas inlet pipeline 2;

the top end of the central tube 1 extends out of a thick raw gas pipeline 3, the raw gas inlet pipeline 2 is positioned above the thick raw gas pipeline 3 and sleeved outside the central tube 1, and the top end of the thick raw gas pipeline 3 is communicated with the raw gas inlet pipeline 2; meanwhile, the central pipe 1 is divided into two sections, namely an upper section pipeline and a lower section pipeline, wherein the upper section pipeline is a part extending out of the raw gas inlet pipeline 2, the lower section pipeline is a part positioned in the raw gas inlet pipeline 2 and the concentrated raw gas pipeline 3, and the caliber of the upper section pipeline is far smaller than that of the lower section pipeline;

The top end of the raw gas inlet pipeline 2 is sealed, the bottom end of the raw gas inlet pipeline 2 is fixedly connected with the top end of the primary air distribution pipeline 4 through a No. 1 flange, and the top end of the primary air distribution pipeline 4 is sealed through a sealing plate;

the porous concentration grid 7 is of a flat plate or curved plate structure, through holes are formed in the plate, one end of the porous concentration grid 7 is fixed on the inner wall of the raw gas inlet pipeline 2, the other end of the porous concentration grid 7 is fixed on a sealing plate at the top end of the first-stage air distribution pipeline 4, and the light raw gas pipeline 5 is positioned right below the porous concentration grid 7;

The split grid 8 is arranged in a channel between the light raw gas pipeline 5 and the primary air distribution pipeline 4 and is used for splitting the gas in the channel into two parts, wherein one part of gas is used for supporting combustion, the other part of gas is used for cooling a water cooled wall on the back fire side of the boiler, slag bonding and high-temperature corrosion are prevented, and the channel in which the other part of gas is positioned is used as a back fire side air channel;

the blunt body 9 is fixed on the inner wall of the bottom of the central tube 1 through a connecting piece, the multiple diffusion flame generator 12 is embedded in an annular channel formed between the central tube 1 and the thick raw gas pipeline 3, and the bottom end of the multiple diffusion flame generator 12 is flush with the bottom end of the central tube 1 and the bottom end of the thick raw gas pipeline 3;

the fire side wall plate 6 and part of the side wall of the primary air distribution pipeline 4 are combined with a first flange plate at the top end of the primary air distribution pipeline 4 to form a fire side air channel; a No. 3 air inlet is formed in the fire side wall plate 6 and is used as an air inlet of a fire side air channel;

the bottom end of the fire side air channel is provided with a guide pipe 6-1, and the guide pipe 6-1 is used for cooling the fire side boiler water wall, preventing slag bonding and high-temperature corrosion after the gas in the fire side air channel is led out;

the bottom end of the fire side air channel is also communicated with the bottom end of the primary air distribution pipeline 4;

the water-cooling coil pipe cooling system 11 is used for cooling the central pipe 1, the thick raw gas pipeline 3 and the thin raw gas pipeline 5.

The second structure of the direct current burner for burning high temperature raw gas is as follows:

The direct-current burner for burning high-temperature raw gas comprises a central tube 1, a raw gas inlet pipeline 2, N concentrated raw gas pipelines 3, a primary air distribution pipeline 4, a light raw gas pipeline 5, a fire side wall plate 6, a porous concentration grid 7, a split grid 8, a blunt body 9, a raw gas diffusion ring 10 and a water-cooling coil pipe cooling system 11; the bottom ends of the central pipe 1, the N concentrated raw gas pipelines 3, the primary air distribution pipeline 4 and the light raw gas pipeline 5 are communicated; a No. 1 air inlet is arranged on the side wall of the raw gas inlet pipeline 2; the wall surface of the first-stage air distribution pipeline 4 is provided with a No. 2 air inlet 4-1; n is an integer greater than or equal to 2;

The central pipe 1 and the primary air distribution pipeline 4 are coaxially arranged from inside to outside in sequence, an annular channel is formed between the central pipe 1 and the primary air distribution pipeline 4, and N concentrated raw gas pipelines 3 are axially symmetrically distributed around the axis of the central pipe 1; the bottom ends of the N concentrated raw gas pipelines 3 are flush, the raw gas diffusion rings 10 are arranged at the bottom ends of the N concentrated raw gas pipelines 3, and the N concentrated raw gas pipelines 3 are communicated with the raw gas diffusion rings 10;

the light raw gas pipelines 5 are arranged in the first-stage air distribution pipeline 4 and outside the N concentrated raw gas pipelines 3, the axes of the first-stage air distribution pipeline 4 are parallel to the axes of the first-stage air distribution pipeline 4 and the axes of the N concentrated raw gas pipelines 3, the light raw gas pipelines 5 are close to the back fire side of the boiler, and the top ends of the light raw gas pipelines 5 are communicated with the raw gas inlet pipeline 2;

The top end of the central tube 1 extends out of a primary air distribution pipeline 4, the raw gas inlet pipeline 2 is positioned above the N concentrated raw gas pipelines 3 and the primary air distribution pipeline 4, and is sleeved outside the central tube 1, and the top ends of the N concentrated raw gas pipelines 3 are communicated with the raw gas inlet pipeline 2;

The porous concentration grid 7 is of a flat plate or curved plate structure, through holes are formed in the plate, one end of the porous concentration grid 7 is fixed on the inner wall of the raw gas inlet pipeline 2, the other end of the porous concentration grid 7 is fixed on a sealing plate at the top end of the primary air distribution pipeline 4, and the light raw gas pipeline 5 is positioned right below the porous concentration grid 7;

the split grid 8 is arranged in a channel between the light raw gas pipeline 5 and the primary air distribution pipeline 4 and is used for splitting the gas in the channel into two parts, wherein one part of the gas is used for supporting combustion, and the other part of the gas is used for cooling the water cooled wall on the back fire side of the boiler, preventing slag bonding and high-temperature corrosion; and the channel in which the other part of gas is positioned is used as a backfire side wind channel;

the blunt body 9 is sleeved and fixed on the outer wall of the bottom of the central tube 1;

Preferably, the split grating 8 of the direct current burner for burning high temperature raw gas with the first and second structures is of a strip structure, and the longitudinal section of the split grating 8 is triangular.

Preferably, the angle A3 of the triangle of the longitudinal section of the split grating 8 has a value of 5 ° to 30 °.

Preferably, in the direct-current burner for burning high-temperature raw gas with the first structure, the bottom end of the raw gas diffusion ring 10 is flush with the bottom end of the primary air distribution pipeline 4, the bottom end of the light raw gas pipeline 5 and the bottom end of the fire side wall plate 6.

Preferably, in the direct-current burner for burning high-temperature raw gas with the first and second structures, the distance between the bottom end face of the blunt body 9 and the bottom end face of the raw gas diffusion ring 10 is H ₁; and H ₁ = (0.2 to 0.5) D1; wherein D1 is the outer diameter of the blunt body 9.

Preferably, in the direct current burner for burning high temperature raw gas with the first structure, the multiple diffusion flame generator 12 is of an annular structure, and M axial nozzles 12-1 are arranged along the circumferential direction of the annular structure, wherein the M axial nozzles 12-1 are axially symmetrically distributed around the axis of the multiple diffusion flame generator 12, and M is an integer greater than 1.

Preferably, the radial cross-section of the axial jets 12-1 is the same or tapered in diameter; wherein, the gradual change mode comprises gradual reduction or gradual expansion.

Preferably, the radial cross section of the axial jets 12-1 tapers or tapers at an included angle of 20 ° to 70 °.

Preferably, in the direct-current burner for burning high-temperature raw gas with the first and second structures, the included angle between the porous concentration grid 7 and the inner wall of the raw gas inlet pipeline 2 is 20-35 degrees, and the included angle between the porous concentration grid and the inner wall of the raw gas inlet pipeline 2 is A ₁,A₁.

Preferably, in the direct current burner for burning high temperature raw gas with the first and second structures, the radial section of the raw gas diffusion ring 10 is rectangular, square or circular, and the diffusion angle a ₂ of the raw gas diffusion ring 10 has a value of 15 ° to 35 °.

Preferably, in the direct-current burner for burning high-temperature raw gas with the first and second structures, the raw gas inlet pipeline 2 is a straight pipe with a rectangular, square or circular radial section;

The central tube 1 is a straight tube with a rectangular, square or circular radial section;

the thick raw gas pipeline 3 is a straight pipe with a rectangular, square or round radial section;

The light raw gas pipeline 5 is a straight pipe with a rectangular, square or a plurality of circles in radial section;

the primary air distribution pipeline 4 is a straight pipe with a rectangular, square or circular radial section.

Preferably, in the direct-current burner for burning high temperature raw gas of the first structure, the water-cooling coil cooling system 11 comprises 3 groups of water-cooling coils 11-1, wherein,

The first group of water-cooling coils 11-1 are coiled on the inner wall of the central tube 1, the second group of water-cooling coils 11-1 are coiled on the outer side wall of the thick raw gas pipeline 3, and the third group of water-cooling coils 11-1 are coiled on the outer side wall of the thin raw gas pipeline 5;

And circulating cooling water is introduced into the 3 groups of water-cooling coils 11-1 for cooling and protecting the central pipe 1, the concentrated raw gas pipeline 3 and the light raw gas pipeline 5.

Preferably, in the direct-current burner for burning high-temperature raw gas of the second structure, the water-cooling coil cooling system 11 comprises three groups of water-cooling coils 11-1, wherein,

The N concentrated raw gas pipelines 3 are surrounded to form an annular structure, and the first group of water-cooling coils 11-1 are coiled on the inner wall of the annular structure surrounded by the N concentrated raw gas pipelines 3; the second group of water-cooling coils 11-1 are coiled on the outer wall of the annular structure surrounded by the N concentrated raw gas pipelines 3;

The third group of water-cooling coils 11-1 are coiled on the outer wall of the light raw gas pipeline 5;

and circulating cooling water is introduced into the 3 groups of water cooling coils 11-1 for cooling and protecting the N concentrated raw gas pipelines 3 and the light raw gas pipeline 5.

Preferably, in the direct-current burner for burning high-temperature raw gas with the first and second structures, the water-cooling coil pipe cooling system 11 also comprises a valve 11-2, a water inlet pipeline 11-3, a down pipe 11-4, a high-pressure circulating pump 11-5 and a water return pipeline 11-6 which are positioned outside the burner;

The down pipe 11-4 is simultaneously communicated with water inlets of the three groups of water-cooling coils 11-1 through a water inlet pipeline 11-3, and the down pipe 11-4 is simultaneously communicated with water return ports of the three groups of water-cooling coils 11-1 through a water return pipeline 11-6;

the valve 11-2 is arranged on the water inlet pipeline 11-3;

The high-pressure circulating pump 11-5 is arranged on the water return pipeline 11-6 and is used for pumping water in the water cooling coil 11-1 back to the downcomer 11-4.

The invention relates to a principle and performance analysis of a direct current burner for burning high-temperature raw gas, which comprises the following steps:

Firing: the invention uses high temperature raw gas as fuel, has three elements of ignition combustion of high temperature, fuel and oxidant, so the invention has no ignition problem in theory, namely absolute ignition.

Stable combustion: the stable combustion of the raw gas is realized by adopting the raw gas multiple diffusion flame and a blunt body: the multiple diffusion flame is absolutely stable in theory, the stable combustion mechanism of the blunt body is utilized by the multiple raw gas diffusion flame, and the heat is not returned by the blunt body vortex, because the back flow gas of the blunt body vortex is central wind or primary air distribution, namely preheated air, but not hot flue gas, and the axial and radial changes are made to the sites of hot gas-solid two-phase flow of raw gas fuel, air, oxidant and combustion products by the blunt body vortex, namely: the distribution of raw gas fuel, air oxidant and combustion products can effectively match the propagation speed of the ignition combustion flame of combustible gas, coke and semicoke particles of the raw gas in a wider speed range in the boundary layer of the outer boundary layer of the blunt body vortex, so that absolute stable combustion in practical sense is realized, and in short, the absolute ignition stable combustion of the raw gas multiple diffusion flame is implemented by means of ignition stable combustion in the boundary layer of the blunt body vortex.

Low NOx: the implementation of three mechanisms of fuel-rich, low temperature, and fuel staged combustion respectively inhibits the occurrence of fuel-type NOx, thermal-type NOx, and reduces NOx to reduce NOx emissions. Different from the essence or purpose of primary and secondary air distribution of coal dust direct-current combustion, the air distribution design requirement of high-temperature raw gas direct-current combustion is as follows: the high-temperature raw gas multiple diffusion flame is provided with a primary air distribution and a secondary air distribution according to a sectional coupling pulverized coal combustion method in an integral burner area of a high-temperature section pulverized coal furnace instead of a burner near-field fuel-rich combustion and gasification principle, so that the high-temperature raw gas fuel-rich combustion and gasification at the temperature level of 1100 ℃ are implemented, the space and time for inhibiting the occurrence of fuel NOx are expanded, and the carbon conversion rate is continuously improved, preferably reaches more than 80 percent along with the development of the high-temperature raw gas fuel-rich combustion and gasification, and the mechanism for inhibiting the occurrence of fuel NOx by the fuel-rich combustion is maximally implemented; on the other hand, the raw gas multiple diffusion flame is designed to occur in the outer boundary layer of the blunt body vortex, which is beneficial to self cooling of flame, and avoids backflow of high-temperature flue gas to the vortex core, the blunt body vortex backflow gas only flows back to the vortex core of the blunt body by small part of central wind or primary wind distribution, so that thermal NOx in the vortex core can be restrained, in particular, compared with concentrated flame, the high-temperature raw gas multiple diffusion flame is relatively easy to implement flame cooling, the secondary wind distribution arranged in a grading way timely mixes with the high-temperature raw gas multiple diffusion flame, the raw gas multiple flame is cooled to maintain combustion and gasification in the whole burner area at the temperature level of 1100 ℃, and the low-temperature combustion can obviously restrain thermal NOx; in addition, the porous plate concentrator is utilized to divide the high-temperature raw gas flow into a thick high-temperature raw gas flow towards the fire side and a thin high-temperature raw gas flow towards the back fire side in the horizontal direction, so that the high-temperature raw gas fuel is subjected to staged combustion in the horizontal direction, and the combustion of the thin high-temperature raw gas flow can reduce NOx generated by the thick high-temperature raw gas flame, thereby reducing NOx emission.

Slag bonding and high temperature corrosion are prevented: all high-temperature raw gas multiple diffusion flames are wrapped by primary air distribution and central air, the outlet of a concentrated high-temperature raw gas channel is regulated by a configured raw gas diffusion ring, particles in high-temperature raw gas are prevented from flushing a water-cooled wall, particles in high-temperature raw gas can be blocked by a horizontal thick-thin separated back-fire side thin-high-temperature raw gas combustion air flow, the particles in high-temperature raw gas can be blocked by an air screen from flushing the water-cooled wall, particles in the high-temperature raw gas can be blocked by a concurrent side air flow on the back-fire side, the temperature near the back-fire side water-cooled wall can be reduced, the vicinity of the back-fire side water-cooled wall can be kept in an oxidizing atmosphere, and finally, high-pressure, reverse-cut circular and countercurrent fire-side air flows which are configured on the fire side from a primary air distribution fan can be independently controlled. Therefore, the implementation of four technologies of a raw gas diffusion ring, horizontal shade, back fire side forward flow side wind and reverse tangential fire side reverse flow side wind can ensure that the near field of the burner and the water wall area nearby the near field of the burner are in a favorable state of low temperature, strong oxidizing atmosphere and no particle scouring, so that the slagging and high temperature corrosion of the wall surface of the burner and the water wall area nearby the burner can be prevented;

High-efficiency combustion: because the high-temperature raw gas direct-current burner adopts the multiple diffusion flame and horizontal shade staged combustion technology, the front-stage mixing of the high-temperature raw gas fuel and the air oxidant in the near field of the direct-current burner is improved compared with concentrated flame, meanwhile, the advantage of the back-stage mixing of tangential combustion is taken over, and the back-tangential configuration of the high-pressure side wind on the fire side which is independently controlled is also beneficial to mixing. Under the favorable conditions of realizing the ignition and stable combustion performance, according to the air distribution principle and the combustion principle of a sectional coupling pulverized coal combustion method, the over-fire air and the over-fire air are scientifically introduced into the area above the burner area in the pulverized coal furnace, the rapid burnout of the oxidizing atmosphere is implemented at the temperature level of 1300 ℃, and the high-efficiency combustion of the raw gas can be implemented under sufficient conditions;

and (3) cooling: the water cooling and air cooling integrated cooling mode is adopted, the water cooling coil pipe cooling system 11 is utilized to implement forced circulation water cooling of the direct-current burner, and the water cooling coil pipe is protected by implementing soot blowing and air cooling in the process of spraying primary air distribution and central air into the furnace;

Load response and low load performance: on the key premise of the absolute ignition and stable combustion principle, the lowest air quantity of the central air and the primary air distribution is designed according to the rated load or rated power (25-30)% of the direct-current burner, and on the premise of continuously supplying high-temperature raw gas, the low-load commercial demand (25-30)% can be safely and effectively met; because the raw coke oven gas is stable against fire, the raw coke oven gas can quickly catch fire and burn stably in a conventional overload range, and compared with direct-current tangential combustion of coal dust, the load, particularly the high load response characteristic, can be obviously accelerated;

Adaptability of coal: the invention can be applied to the sectional coupling combustion of wide coal types as long as coal, biomass and mixtures thereof can be reformed into raw coke oven gas in a preferable low-temperature-section double-vortex rapid fluidized bed through a sectional coupling coal powder combustion device, and the coal combustion can be efficiently and cleanly realized in a high-temperature-section coal powder furnace for sectional coupling coal powder combustion by introducing the high-temperature raw coke oven gas direct-current burner for combustion.

The invention has the beneficial effects that the invention provides a direct-current burner for burning high-temperature raw coke oven gas for the existing sectional coupling pulverized coal combustion technology, and the fuel is the high-temperature raw coke oven gas, wherein the raw coke oven gas is a gas-solid two-phase flow which is generated by a preferable double-vortex rapid fluidized bed, has the pressure of less than 3MPa and the temperature of 500-980 ℃, and the combustible gas only contains semicoke and coke particles with the particle size range of less than 70 microns, so the invention is a novel direct-current burner for special fuel.

According to the direct-current burner for burning high-temperature raw gas, concentrated flames in traditional pulverized coal combustion are reformed into multiple raw gas diffusion flames which are distributed symmetrically in the circumferential direction and the center by being arranged on the pulverized coal furnace for sectional coupling pulverized coal combustion, so that the direct-current burner does not have the ignition problem, namely absolute ignition and stable combustion in the boundary layer of a blunt body vortex; in the whole burner area, the fuel-rich low-temperature combustion at 1100 ℃ not only expands the action space and time of the reducing atmosphere combustion for inhibiting the generation mechanism of fuel NOx, but also can inhibit the generation of thermal NOx, and the diffusion flame fires and burns stably in the outer boundary layer of the blunt body vortex, thereby being beneficial to cooling the waste gas flame and preventing the high-temperature flue gas from flowing back into the blunt body vortex, and particularly being beneficial to inhibiting the generation of thermal NOx; the theory and structural design of central wind and primary wind distribution wrapping high-temperature multiple raw gas diffusion flame, the cooperative configuration of a raw gas diffusion ring, horizontal shade grading, back fire side forward side wind and reverse tangential reverse side wind improve the high-temperature corrosion resistance and slag bonding resistance of a burner and a water-cooled wall area near the burner; the abrasion resistance of the burner is improved by burning the raw gas instead of directly burning the raw coal dust; the invention also provides a principle and a method for comprehensively cooling and protecting the direct-current burner by water cooling and air cooling, and the comprehensive cooling technology of the air cooling and water cooling coil cooling system has the advantages that the defect of easy leakage of cooling of a conventional water cooling jacket is avoided, the water system of cooling water cannot be polluted, the safety and the reliability are realized, and the service life of the burner is prolonged; absolute fire stable combustion improves load response capability; the absolute ignition and stable combustion creates a sufficient favorable condition for efficient combustion.

In summary, the invention realizes the efficient clean direct-current combustion of raw gas based on the comprehensive cooling technology of multiple high-temperature raw gas diffusion flames, ignition stable combustion in a blunt body vortex outer boundary layer, horizontal thick and thin fuel staged combustion, back fire side concurrent side wind, independently controlled high-pressure reverse tangential side countercurrent side wind, water cooling and air cooling, has the characteristics of absolute ignition stable combustion, remarkable inhibition of fuel type and thermal type NOx generation, high efficiency, slag bonding prevention, high-temperature corrosion, good load response and reliable cooling, and is suitable for the staged coupling pulverized coal combustion of wide coal types.

Drawings

FIG. 1 is a schematic diagram of a first structure of a direct current burner for burning high temperature raw gas according to the present invention;

FIG. 2 is a schematic view, partially in section, of FIG. 1 in the direction A-A;

FIG. 3 is a schematic diagram of a second construction of a direct current burner for burning high temperature raw gas according to the present invention;

FIG. 4 is a schematic view in partial cross-section in the direction B-B of FIG. 3;

FIG. 5 is a schematic diagram of the structure of the multiple diffusion flame generator 12;

Fig. 6 is a schematic diagram of a water-cooled coil cooling system 11.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.

Referring to fig. 1 and 2, the direct current burner for burning high temperature raw gas according to the present embodiment includes a central tube 1, a raw gas inlet pipe 2, a concentrated raw gas pipe 3, a primary air distribution pipe 4, a light raw gas pipe 5, a fire side wall plate 6, a porous concentrating grid 7, a split grid 8, a blunt body 9, a raw gas diffusion ring 10, a water-cooled coil pipe cooling system 11 and a multiple diffusion flame generator 12; the bottom ends of the central pipe 1, the concentrated raw gas pipeline 3, the primary air distribution pipeline 4 and the light raw gas pipeline 5 are communicated; a No. 1 air inlet is arranged on the side wall of the raw gas inlet pipeline 2; the wall surface of the primary air distribution pipeline 4 is provided with a No. 2 air inlet 4-1;

The central tube 1 and the concentrated raw gas pipeline 3 are coaxially arranged from inside to outside in sequence, the bottom ends of the central tube 1 and the concentrated raw gas pipeline 3 are flush, and an annular channel is formed between the central tube 1 and the concentrated raw gas pipeline 3; the bottom end of the thick raw gas pipeline 3 is provided with a raw gas diffusion ring 10, and the primary air distribution pipeline 4 is sleeved outside the thick raw gas pipeline 3; the light raw gas pipeline 5 is arranged in an annular channel formed between the concentrated raw gas pipeline 3 and the first-stage air distribution pipeline 4, the light raw gas pipeline 5 is close to the back fire side of the boiler, and the axis of the light raw gas pipeline 5 is parallel to the axis of the first-stage air distribution pipeline 4; the top end of the raw gas pipeline 5 is communicated with the raw gas inlet pipeline 2;

The direct-current burner with the first structure is characterized in that a central pipe 1 is divided into two sections, namely an upper section pipeline and a lower section pipeline, wherein the upper section pipeline is a part extending out of a raw gas inlet pipeline 2, the lower section pipeline is a part which is positioned in the raw gas inlet pipeline 2 and continuously penetrates through a separation sealing plate with the center of a concentrated raw gas pipeline 3 symmetrically, and the caliber of the upper section pipeline is far smaller than that of the lower section pipeline; the setting mode is used for controlling the flow speed and the flow quantity of the thick raw gas after the thick raw gas is separated from the thin raw gas.

referring to fig. 3 and 4, the direct current burner for burning high temperature raw gas according to the present embodiment includes a central tube 1, raw gas inlet pipes 2, N thick raw gas pipes 3, a primary air distribution pipe 4, a light raw gas pipe 5, a fire side wall plate 6, a porous concentrating grid 7, a split grid 8, a blunt body 9, a raw gas diffusion ring 10 and a water cooling coil pipe cooling system 11; the bottom ends of the central pipe 1, the N concentrated raw gas pipelines 3, the primary air distribution pipeline 4 and the light raw gas pipeline 5 are communicated; a No. 1 air inlet is arranged on the side wall of the raw gas inlet pipeline 2; the wall surface of the primary air distribution pipeline 4 is provided with a No. 2 air inlet 4-1; n is an integer greater than or equal to 2;

The raw gas is a gas-solid two-phase flow with semicoke and coke particles with particle diameters smaller than 70 microns, wherein the pressure of the gas is smaller than 3MPa, the temperature is 500-980 ℃, and the combustible gas only contains semicoke and coke particles with particle diameters smaller than 70 microns. The porous concentration grid 7 can realize the concentration separation of raw gas introduced into the raw gas inlet pipeline 2, is used for realizing the horizontal concentration separation of the high-temperature raw gas and implementing the fuel staged combustion of the high-temperature raw gas, and has the characteristics that the volume flow ratio of the high-temperature raw gas to the low-temperature raw gas is 8:2 to 5:5, and the resistance loss is not more than 20mmH ₂ O column; the equivalent aperture of the holes vertically opened on the porous concentrating grid 7 can be 5mm to 60mm, and the total flow area of the holes is at least larger than the vertical projection area of the porous concentrating grid 7 so as to realize rapid flow equalization under the minimum flow resistance. The top end of the central tube 1 penetrates out of the raw gas inlet pipeline 2, and the bottom end of the central tube does not allow the raw gas inlet pipeline to extend out of the outlet of the direct-current burner;

When in use, the top end of the light raw gas pipeline 5 arranged on the back fire side is communicated and connected on the separation sealing plate in a sealing way, the light raw gas pipeline 5 is communicated with the raw gas inlet pipeline 2 and is used for spraying light raw gas, when the gas screen type high-temperature raw gas particles are blocked to wash the near-field water-cooled wall at the back fire side, the combustion of the concentrated high-temperature raw gas is carried out by mixing combustion with the wrapped primary air distribution, so that the reduction of NOx is enhanced, and the emission of NOx is reduced.

The implementation of the back fire side air channel is different from the implementation of the traditional side air of direct-current pulverized coal combustion by using a special channel, the back fire side air channel is realized by arranging the split grating 8 in the vertical direction of the back fire side of the outlet of the primary air distribution pipeline 4, the structure is simple, the side air channel is not influenced, the split grating 8 also has a blunt body function, the main function is diversion, the back fire side air and the primary air distribution are concurrent flow, and the concurrent flow and the tangential circle are opposite to each other, so as to delay mixing, promote local oxidizing atmosphere combustion, reduce the temperature near a water wall, create oxidizing atmosphere and air screen type to prevent particles from scouring the water wall, and prevent slag formation and high-temperature corrosion on the back fire side;

The fire side edge wind is reversely tangent and arranged, and the outside is wrapped with the main combustion air flow of the forward tangent and is mixed with the raw gas in a reverse flow manner; the fire side air channel is an independent channel constructed by utilizing the primary air distribution pipeline 4 to the fire side wall surface so as to be controlled independently, the top end of the fire side air channel is sealed by a separation sealing plate, a No. 3 air inlet is formed in the fire side wall plate 6, the included angle A ₄ between the jet direction of the fire side air channel and the fire side boiler water wall is larger than the jet diffusion angle of the fire side air channel and smaller than (45-alpha), wherein alpha is the jet deflection angle of the secondary air distribution forward tangential jet in the boiler, and the fire side air is independently provided by the primary air distribution fan, so that the penetrating power of the fire side air jet with independent control and higher pressure is stronger, the water wall is protected on the fire side, slag formation and high-temperature corrosion are prevented, and meanwhile, the fire side boiler water wall is beneficial to being mixed with fuel, the tangential combustion rotation momentum can be partially dissipated, and the temperature deviation of a superheater is improved.

When the direct-current burner with the two structures is specifically used, the water-cooling coil cooling system 11 is started firstly, and air is introduced into the central tube 1, the primary air distribution pipeline 4 and the fire side air pipe channel, wherein the air is introduced into the primary air distribution pipeline 4, namely: air is introduced into the side air channel of the back fire; after high-temperature raw coke oven gas is introduced into a raw coke oven gas inlet pipeline 2 and is divided into two raw coke oven gas flows through a porous concentration grid 7, the two raw coke oven gas flows are respectively introduced into an annular raw coke oven gas channel and a raw coke oven gas pipeline 5 formed by the outer wall of a central pipe 1 and the inner wall of a raw coke oven gas pipeline 3 aiming at a direct current burner with a first structure, and the two raw coke oven gas flows are simultaneously introduced into N raw coke oven gas pipelines 3 and the raw coke oven gas flows are simultaneously introduced into the raw coke oven gas pipeline 5 aiming at a direct current burner with a second structure; by means of an ignition device (such as an oil gun and a high-energy ignition device) which can be thrown in by the central tube 1, a plurality of thick raw gas streams which are ejected by the multiple diffusion flame generators 12 in the first type structure flow burner or the N thick raw gas pipelines 3 of the second type structure flow burner and are circumferentially and symmetrically distributed are ignited until stable multi-strand thick raw gas flames are formed in the outer boundary layer of the vortex of the blunt body 9, the ignition device is withdrawn, meanwhile, the oxidizing atmosphere of the thin raw gas stream at the back fire side ignites stably and reduces NOx possibly generated by the thick raw gas combustion, and the ignition and stable combustion positions of the thick raw gas diffusion flame from the nozzle of the blunt body 9 can be properly adjusted by the positive interference of central wind on the reflux vortex of the blunt body 9 by the central tube 1; the blunt body 9 standardizes the radial characteristic scale of the blunt body vortex, the central air or the primary air distribution, except that a small part flows back into the blunt body vortex, the synergistic effect of the central air or the primary air distribution and the primary air distribution is mostly used for the stable ignition and combustion of a plurality of concentrated raw gas, so as to form multiple diffusion flames with absolute stable ignition and combustion, the concentrated raw gas forms stable multiple diffusion flames after being ignited, and in the process of the development of the downstream fuel-rich combustion, the secondary air distribution configured in a boiler is timely mixed and cooled by utilizing the conventional technology, the raw gas combustion and gasification at the temperature level of 1100 ℃ are implemented in the integral combustor area of the pulverized coal furnace, and after the thermochemical conversion of the reducing atmosphere in the stage, the carbon conversion rate reaches more than 80 percent, so that the action space and time of the fuel-rich combustion reducing NOx emission mechanism are fully expanded, the generation of fuel-type NOx is restrained, the raw gas combustion at the relatively low temperature of 1100 ℃ is also can be fully restrained, and the generation of thermal-type NOx is restrained; the subsequent oxidizing atmosphere area above the combustion area of the pulverized coal furnace reasonably organizes over-fire air and over-fire air, and the raw gas is fully burnt under the condition to realize efficient clean combustion.

In the process of the raw gas combustion, air is continuously introduced into the central tube 1, so that the flue gas is prevented from flowing backward, the direct-current burner is cooled in the center, and the end face of the central tube and the surface of the blunt body are prevented from slagging and high-temperature corrosion.

When the device is used, the lowest air quantity of the primary air distribution and the central air is designed according to the rated load of the direct-current burner or the rated power (25-30)% of the direct-current burner.

Under the condition of furnace shutdown, firstly, raw gas is stopped being introduced until the raw gas is completely cooled, and then, the primary air distribution, the secondary air distribution, the central air distribution and the water cooling coil pipe cooling system 11 are sequentially stopped.

The water cooling coil pipe cooling system 11 is cooled by central wind and primary air distribution, ash is removed, and the integrated cooling of water cooling and air cooling of the burner is implemented to exert the respective cooling advantages, so that the cooling protection of the direct-current burner is reliably realized.

The direct-current burner for burning high-temperature raw gas changes the concentrated flame of traditional pulverized coal combustion into a design of multiple diffusion flames which are distributed symmetrically along the circumferential axis, and creates favorable conditions for ignition and stable combustion in the outer boundary layer of a blunt body vortex, inhibiting the generation of fuel, especially thermal NOx, improving the slagging resistance and high-temperature corrosion resistance of the burner and the water wall in the area near the burner, improving the wear of the burner, cooling and prolonging the service life of the burner and improving the load response capability;

In the whole burner area, the fuel-rich combustion can deeply inhibit the occurrence of fuel type NOx, the absolute ignition stable combustion and multiple diffusion flame of the thick raw gas in the outer boundary layer of the blunt body vortex are timely mixed and cooled through the secondary air distribution arranged by adopting the conventional technology, the low-temperature combustion at the temperature level of 1100 ℃ is implemented, the occurrence of thermal type NOx can be obviously inhibited, and the horizontal gradation combustion can reduce various NOx possibly occurring;

The direct-current burner has no ignition problem, expands the adaptability of coal types, and has absolute stable combustion performance in theory because of the absolute stable combustion of diffusion flame; the horizontal shade separation and raw gas diffusion ring 10 and the concurrent side wind on the back fire side and the reverse tangential countercurrent side wind on the fire side act cooperatively on the water-cooled wall in the area near the direct-current burner, so that slag bonding and high-temperature corrosion can be effectively prevented; the comprehensive cooling technology of the air-cooled water-cooled cooling coil cooling system 11 has the advantages that the defect of easy leakage of a water cooling jacket is overcome, the cooling water system is not polluted, and the safety and the reliability are realized; as the fuel is raw gas, compared with direct-current pulverized coal combustion, the wear resistance of the burner is improved fundamentally, and the direct-current burner for burning high-temperature raw gas provided by the invention has the advantages of high efficiency and clean combustion.

What is stated in particular is: the structure and relative positional relationship of the center tube 1 and the blunt body 9 in the direct current burner of the first structure may be substituted for the structure and relative positional relationship of the center tube 1 and the blunt body 9 in the direct current burner of the second structure; or N concentrated raw gas pipelines 3 in the direct current burner with the second structure can replace the concentrated raw gas pipelines 3 and the multiple diffusion flame generator 12 in the direct current burner with the first structure; conversely, the concentrated raw gas pipeline 3 and the multiple diffusion flame generator 12 in the first structure direct current burner can also replace N concentrated raw gas pipelines 3 in the second structure direct current burner; or the structure and the relative position relation of the central tube 1 and the blunt body 9 in the direct-current burner with the second structure can also replace the structure and the relative position relation of the central tube 1 and the blunt body 9 in the direct-current burner with the first structure, thereby forming the third structure and the fourth structure of the direct-current burner for burning high-temperature raw gas.

Still further, referring specifically to fig. 1 and 3, in the dc burner of the first or second structure, the split grating 8 has a long strip structure, and the longitudinal section of the split grating 8 has a triangular shape.

Still further, referring specifically to fig. 1 and 3, the apex angle a ₃ of the triangle in the longitudinal section of the split gate 8 has a value of 5 ° to 30 °.

Still further, referring specifically to fig. 1, in the dc burner of the first structure, the bottom ends of the raw gas diffusion ring 10 are flush with the bottom ends of the primary air distribution duct 4, the light raw gas duct 5 and the fire side wall plate 6.

Still further, referring specifically to fig. 1 and 3, in the dc burner of the first or second structure, the distance between the bottom end face of the blunt body 9 and the bottom end face of the raw gas diffusion ring 10 is H ₁; and H ₁ = (0.2 to 0.5) D1; wherein D1 is the outer diameter of the blunt body 9.

Still further, referring to fig. 5 specifically, in the dc burner with the first structure, the multiple diffusion flame generator 12 has an annular structure, and M axial ports 12-1 are disposed along the circumferential direction of the annular structure, where the M axial ports 12-1 are axisymmetrically distributed around the axis of the multiple diffusion flame generator 12, and M is an integer greater than 1.

In the preferred embodiment, the M axial nozzles 12-1 uniformly opened in the circumferential direction enable the concentrated raw gas to be sprayed out from the axial nozzles 12-1, reconstructed into a plurality of concentrated raw gas streams, and the M concentrated raw gas streams are ignited to form multiple diffusion flames, and the multiple flames are convenient to cool, so that the method is one of the keys for realizing absolute stability and suppression of thermal NOx for burning the raw gas fuel direct-current burner.

Still further, with particular reference to FIG. 5, the radial cross-section of the axial jets 12-1 is the same or tapered in diameter; wherein, the gradual change mode comprises gradual reduction or gradual expansion.

In the preferred embodiment, the axial nozzle 12-1 is configured to gradually expand or gradually contract to accelerate or decelerate the gas flow of the concentrated raw gas to be sprayed into the hearth, so as to realize control of the spraying momentum of the concentrated raw gas.

Still further, referring specifically to FIG. 5, the radial cross-section of the axial jets 12-1 tapers or tapers at an included angle of 20 to 70.

Still further, referring to fig. 1 and 3, in the direct current burner of the first or second structure, the included angle between the porous concentrating grid 7 and the inner wall of the raw gas inlet pipe 2 is a ₁,A₁, which has a value of 20 ° to 35 °.

Still further, referring to fig. 1 and 3, in the direct current burner of the first or second structure, the radial section of the raw gas diffusion ring 10 is rectangular, square or circular, and the diffusion angle a ₂ of the raw gas diffusion ring 10 has a value of 15 ° to 35 °.

Still further, referring specifically to fig. 1 to 4, in the direct current burner of the first or second structure, the raw gas inlet pipe 2 is a straight pipe having a rectangular, square or circular radial cross section;

Still further, referring specifically to fig. 1, in the first construction of the direct current burner, the direct current burner for burning high temperature raw gas, the water-cooled coil cooling system 11 comprises 3 sets of water-cooled coils 11-1, wherein,

Still further, referring specifically to fig. 3, in the second construction of the direct current burner, the direct current burner for burning high temperature raw gas, the water-cooled coil cooling system 11 comprises three sets of water-cooled coils 11-1, wherein,

The circulating cooling water is introduced into all the water-cooling coils 11-1 for carrying out forced circulation cooling protection on the cooling water of the pipelines forming the thick and thin raw gas channels.

All the water-cooling coils 11-1 are made of heat-resistant and pressure-resistant materials such as 15CrMo, and other parts of the direct-current burner for burning high-temperature raw gas can be made of aluminum oxide iron alloy, HAYNES 188 alloy or heat-resistant steel.

In the first and second direct current burner structures, all the water cooling coils 11-1 are cooled by central air or/and primary air distribution respectively to remove ash, and the water cooling and air cooling comprehensive cooling of the burner is implemented to exert the respective cooling advantages, so that the cooling protection of the burner is reliably realized.

In particular applications, all of the water cooling coils 11-1 may be in a multi-layer staggered configuration in the radial direction, preferably in a single layer configuration.

Still further, referring specifically to FIG. 6, in the first or second construction of the direct current burner, the direct current burner for burning high temperature raw gas, the water cooling coil cooling system 11 further comprises a valve 11-2, a water inlet line 11-3, a down pipe 11-4, a high pressure circulation pump 11-5 and a water return line 11-6 which are located outside the burner;

the valve 11-2 is arranged on the water inlet pipeline 11-3;

Further, the water cooled coil cooling system 11 operates at a pressure slightly higher than the furnace pressure.

In the preferred embodiment, the operating pressure of the water-cooled coil cooling system 11 is set slightly higher than the furnace pressure in order to prevent the cooling water of the water-cooled coil cooling system 11 from being contaminated by unexpected leakage.

Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in ways other than as described in the original claims. It is also to be understood that features described in connection with separate embodiments may be used in other described embodiments.

Claims

1. The direct-current burner for burning high-temperature raw gas is characterized by comprising a central tube (1), a raw gas inlet pipeline (2), a concentrated raw gas pipeline (3), a primary air distribution pipeline (4), a light raw gas pipeline (5), a fire side wall plate (6), a porous concentrating grid (7), a split grid (8), a blunt body (9), a raw gas diffusion ring (10), a water-cooling coil pipe cooling system (11) and a multiple diffusion flame generator (12); the bottom ends of the central pipe (1), the thick raw gas pipeline (3), the first-stage air distribution pipeline (4) and the thin raw gas pipeline (5) are communicated; a No. 1 air inlet is arranged on the side wall of the raw gas inlet pipeline (2); a No. 2 air inlet (4-1) is arranged on the wall surface of the primary air distribution pipeline (4);

The central pipe (1) and the concentrated raw gas pipeline (3) are coaxially arranged from inside to outside in sequence, the bottom ends of the central pipe and the concentrated raw gas pipeline are flush, and an annular channel is formed between the central pipe (1) and the concentrated raw gas pipeline (3); the bottom end of the thick raw gas pipeline (3) is provided with a raw gas diffusion ring (10), and the primary air distribution pipeline (4) is sleeved outside the thick raw gas pipeline (3); the light raw gas pipeline (5) is arranged in an annular channel formed between the thick raw gas pipeline (3) and the first-stage air distribution pipeline (4), the light raw gas pipeline (5) is close to the back fire side of the boiler, and the axis of the light raw gas pipeline (5) is parallel to the axis of the first-stage air distribution pipeline (4); the top end of the raw gas pipeline (5) is communicated with the raw gas inlet pipeline (2);

The top end of the central tube (1) extends out of the thick raw gas pipeline (3), the raw gas inlet pipeline (2) is positioned above the thick raw gas pipeline (3) and sleeved outside the central tube (1), and the top end of the thick raw gas pipeline (3) is communicated with the raw gas inlet pipeline (2); meanwhile, the central pipe (1) is divided into two sections, namely an upper section pipeline and a lower section pipeline, wherein the upper section pipeline is a part extending out of the raw gas inlet pipeline (2), the lower section pipeline is a part positioned in the raw gas inlet pipeline (2) and the concentrated raw gas pipeline (3), and the caliber of the upper section pipeline is far smaller than that of the lower section pipeline;

the top end of the raw gas inlet pipeline (2) is sealed, the bottom end of the raw gas inlet pipeline (2) is fixedly connected with the top end of the primary air distribution pipeline (4) through a No.1 flange, and the top end of the primary air distribution pipeline (4) is sealed through a sealing plate;

the porous concentration grid (7) is of a flat plate or curved plate structure, through holes are formed in the plate, one end of the porous concentration grid (7) is fixed on the inner wall of the raw gas inlet pipeline (2), the other end of the porous concentration grid is fixed on a sealing plate at the top end of the primary air distribution pipeline (4), and the light raw gas pipeline (5) is positioned under the porous concentration grid (7);

The split grid (8) is arranged in a channel between the light raw gas pipeline (5) and the primary air distribution pipeline (4) and is used for splitting the gas in the channel into two parts, wherein one part of gas is used for supporting combustion, the other part of gas is used for cooling a water cooling wall on the back fire side of the boiler, slag bonding and high-temperature corrosion are prevented, and the channel in which the other part of gas is positioned is used as a back fire side air channel;

The split grating (8) is of a strip-shaped structure, and the longitudinal section of the split grating (8) is triangular;

The blunt body (9) is fixed on the inner wall of the bottom of the central tube (1) through a connecting piece, the multiple diffusion flame generator (12) is embedded in an annular channel formed between the central tube (1) and the thick raw gas pipeline (3), and the bottom end of the multiple diffusion flame generator (12) is flush with the bottom end of the central tube (1) and the bottom end of the thick raw gas pipeline (3);

The distance between the bottom end surface of the blunt body (9) and the bottom end surface of the raw gas diffusion ring (10) is H ₁; and H ₁ = (0.2 to 0.5) D1; wherein D1 is the outer diameter of the blunt body (9);

The fire side wall plate (6) and part of the side wall of the primary air distribution pipeline (4) are surrounded by a first flange plate at the top end of the primary air distribution pipeline (4) to form a fire side air channel; a No.3 air inlet is formed in the fire side wall plate (6), and the No.3 air inlet is used as an air inlet of a fire side air channel;

The bottom end of the fire side edge wind channel is provided with a guide pipe (6-1), and the guide pipe (6-1) is used for cooling the fire side boiler water wall, preventing slag bonding and high-temperature corrosion after the gas in the fire side edge wind channel is led out;

the bottom end of the fire side air channel is also communicated with the bottom end of the primary air distribution pipeline (4);

the water-cooling coil pipe cooling system (11) is used for cooling the central pipe (1), the thick raw gas pipeline (3) and the thin raw gas pipeline (5).

2. The direct current burner for burning high temperature raw gas according to claim 1, wherein the bottom end of the raw gas diffusion ring (10) is flush with the bottom end of the primary air distribution pipeline (4), the bottom end of the light raw gas pipeline (5) and the bottom end of the fire side wall plate (6).

3. The direct current burner for burning high temperature raw gas according to claim 1, wherein the multiple diffusion flame generator (12) is of a ring structure, and M axial nozzles (12-1) are arranged along the circumferential direction of the ring structure, wherein the M axial nozzles (12-1) are axisymmetrically distributed around the axis of the multiple diffusion flame generator (12), and M is an integer greater than 1.

4. A direct-current burner for burning high temperature raw gas according to claim 3, characterized in that the radial section of the axial jets (12-1) is of the same or gradual diameter; wherein, the gradual change mode comprises gradual reduction or gradual expansion.

5. The direct-current burner for burning high-temperature raw gas according to claim 4, wherein the radial section of the axial nozzle (12-1) is tapered or divergent at an included angle of 20 ° to 70 °.

6. The direct-current burner for burning high-temperature raw gas according to claim 1, wherein the apex angle of a triangle a ₃ of the longitudinal section of the split grid (8) takes a value of 5-30 °.

7. The direct current burner for burning high temperature raw gas according to claim 1, wherein the water-cooled coil cooling system (11) comprises 3 sets of water-cooled coils (11-1), wherein,

The first group of water-cooling coils (11-1) are coiled on the inner wall of the central tube (1), the second group of water-cooling coils (11-1) are coiled on the outer side wall of the thick raw gas pipeline (3), and the third group of water-cooling coils (11-1) are coiled on the outer side wall of the thin raw gas pipeline (5);

And circulating cooling water is introduced into the 3 groups of water-cooling coils (11-1) for cooling and protecting the central pipe (1), the concentrated raw gas pipeline (3) and the light raw gas pipeline (5).

8. The direct current burner for burning high temperature raw gas according to claim 7, wherein the water cooling coil cooling system (11) further comprises a valve (11-2) located outside the burner, a water inlet line (11-3), a down pipe (11-4), a high pressure circulation pump (11-5) and a water return line (11-6);

The descending pipe (11-4) is simultaneously communicated with water inlets of the three groups of water-cooling coils (11-1) through a water inlet pipeline (11-3), and the descending pipe (11-4) is simultaneously communicated with water return ports of the three groups of water-cooling coils (11-1) through a water return pipeline (11-6);

The valve (11-2) is arranged on the water inlet pipeline (11-3);

the high-pressure circulating pump (11-5) is arranged on the water return pipeline (11-6) and is used for pumping water in the water cooling coil pipe (11-1) back to the downcomer (11-4).

9. The direct-current burner for burning high-temperature raw gas according to claim 1, wherein the included angle between the porous concentration grid (7) and the inner wall of the raw gas inlet pipeline (2) is a ₁,A₁ with a value of 20-35 degrees.

10. The direct-current burner for burning high-temperature raw gas according to claim 1, wherein the radial section of the raw gas diffusion ring (10) is rectangular, square or circular, and the diffusion angle a ₂ of the raw gas diffusion ring (10) has a value of 15-35 °.

11. The direct-current burner for burning high-temperature raw gas according to claim 1, wherein the raw gas inlet pipeline (2) is a straight pipe with a rectangular, square or circular radial section;

The central tube (1) is a straight tube with a rectangular, square or round radial section;

The thick raw gas pipeline (3) is a straight pipe with a rectangular, square or round radial section;

The light raw gas pipeline (5) is a straight pipe with a rectangular, square or a plurality of circles in radial section;

the primary air distribution pipeline (4) is a straight pipe with a rectangular, square or circular radial section.

12. The direct-current burner for burning high-temperature raw gas is characterized by comprising a central tube (1), a raw gas inlet pipeline (2), N concentrated raw gas pipelines (3), a primary air distribution pipeline (4), a light raw gas pipeline (5), a fire side wall plate (6), a porous concentration grid (7), a split grid (8), a blunt body (9), a raw gas diffusion ring (10) and a water-cooling coil cooling system (11); the bottom ends of the central pipe (1), the N thick raw gas pipelines (3), the first-stage air distribution pipeline (4) and the thin raw gas pipeline (5) are communicated; a No. 1 air inlet is arranged on the side wall of the raw gas inlet pipeline (2); a No.2 air inlet (4-1) is arranged on the wall surface of the primary air distribution pipeline (4); n is an integer greater than or equal to 2;

The central pipe (1) and the primary air distribution pipeline (4) are coaxially arranged from inside to outside in sequence, an annular channel is formed between the central pipe (1) and the primary air distribution pipeline (4), and N concentrated raw gas pipelines (3) are axially symmetrically distributed around the axis of the central pipe (1); the bottom ends of the N concentrated raw gas pipelines (3) are flush, the raw gas diffusion rings (10) are arranged at the bottom ends of the N concentrated raw gas pipelines (3), and the N concentrated raw gas pipelines (3) are communicated with the raw gas diffusion rings (10);

the light raw gas pipeline (5) is arranged in the first-stage air distribution pipeline (4) and outside the N thick raw gas pipelines (3), the axis of the first-stage air distribution pipeline (4) is parallel to the axis of the first-stage air distribution pipeline (4) and the axis of the N thick raw gas pipelines (3), the light raw gas pipeline (5) is close to the back fire side of the boiler, and the top end of the light raw gas pipeline (5) is communicated with the raw gas inlet pipeline (2);

The top end of the central tube (1) extends out of the first-stage air distribution pipeline (4), the raw gas inlet pipeline (2) is positioned above the N concentrated raw gas pipelines (3) and the first-stage air distribution pipeline (4), and is sleeved outside the central tube (1), and the top ends of the N concentrated raw gas pipelines (3) are communicated with the raw gas inlet pipeline (2);

The split grid (8) is arranged in a channel between the light raw gas pipeline (5) and the primary air distribution pipeline (4) and is used for splitting the gas in the channel into two parts, wherein one part of gas is used for supporting combustion, and the other part of gas is used for cooling the water cooling wall on the backfire side of the boiler, preventing slag bonding and high-temperature corrosion; and the channel in which the other part of gas is positioned is used as a backfire side wind channel;

The blunt body (9) is sleeved and fixed on the outer wall of the bottom of the central tube (1); the distance between the bottom end surface of the blunt body (9) and the bottom end surface of the raw gas diffusion ring (10) is H ₁; and H ₁ = (0.2 to 0.5) D1; wherein D1 is the outer diameter of the blunt body (9);

13. The direct current burner for burning high temperature raw gas according to claim 12, wherein the included angle between the porous concentrating grid (7) and the inner wall of the raw gas inlet pipeline (2) is a ₁,A₁ with a value of 20-35 degrees.

14. The direct current burner for burning high temperature raw gas according to claim 12, characterized in that the radial section of the raw gas diffusion ring (10) is rectangular, square or circular, and the diffusion angle a ₂ of the raw gas diffusion ring (10) has a value of 15 ° to 35 °.

15. The direct-current burner for burning high-temperature raw gas according to claim 12, wherein the raw gas inlet pipeline (2) is a straight pipe with a rectangular, square or circular radial section;

16. The direct current burner for burning high temperature raw gas according to claim 12, wherein the water-cooled coil cooling system (11) comprises three sets of water-cooled coils (11-1), wherein,

The N concentrated raw gas pipelines (3) are surrounded to form an annular structure, and the first group of water-cooling coils (11-1) are coiled on the inner wall of the annular structure surrounded by the N concentrated raw gas pipelines (3); the second group of water-cooling coils (11-1) are coiled on the outer wall of the annular structure surrounded by the N concentrated raw gas pipelines (3);

the third group of water-cooling coils (11-1) are coiled on the outer wall of the light raw gas pipeline (5);

and circulating cooling water is introduced into the 3 groups of water cooling coils (11-1) for cooling and protecting the N concentrated raw gas pipelines (3) and the light raw gas pipeline (5).

17. The direct current burner for burning high temperature raw gas according to claim 16, wherein the water cooling coil cooling system (11) further comprises a valve (11-2) located outside the burner, a water inlet line (11-3), a down pipe (11-4), a high pressure circulation pump (11-5) and a water return line (11-6);

The valve (11-2) is arranged on the water inlet pipeline (11-3);