CN110986039B

CN110986039B - Gas molecule collision diffusion premixing low-nitrogen combustion device and combustion head thereof

Info

Publication number: CN110986039B
Application number: CN201911307195.3A
Authority: CN
Inventors: 史星宇
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-12-18
Filing date: 2019-12-18
Publication date: 2021-12-28
Anticipated expiration: 2039-12-18
Also published as: CN114135870B; CN114135870A; CN110986039A

Abstract

The invention discloses a gas molecule collision diffusion premixing low-nitrogen combustion device and a combustion head thereof. The combustion head comprises a combustion head body, and the combustion head body is provided with a central pipeline, a plurality of first annular layer pipelines, a plurality of second annular layer pipelines and an annular flame forming area; the first annular layer and the second annular layer are sequentially arranged between the central pipeline and the annular flame forming area; according to the invention, the first annular layer pipeline and the second annular layer pipeline are arranged on the periphery of the central pipeline, so that the combustion head body can form a plurality of mutually independent premixing areas on the periphery of the central pipeline along the radial direction, and the normal work of other areas cannot be influenced if one premixing area cannot work normally due to faults in the combustion process. The fuel gas and the air can be fully premixed, so that no local high-temperature point exists during combustion, and the generation of nitrogen oxides can be effectively and remarkably reduced.

Description

Gas molecule collision diffusion premixing low-nitrogen combustion device and combustion head thereof

Technical Field

The invention relates to a combustion device, in particular to a low-nitrogen combustion device which realizes full premixing of gas and air through collision and diffusion of the gas and the air.

Background

According to the statistics of the Chinese energy report, about 40 thousands of industrial boilers used in China by 2017, and the number of small civil boilers is larger (no statistical data is available temporarily). With the strict requirements of the state on environmental protection, environmental protection departments in various regions continuously issue documents and require that old boilers are required to be discharged and transformed to reach standards, and the number of clean energy resources is expected to reach more than 70% by 2021, so that the total amount is huge. Wherein, most of the boiler reconstruction is to replace the low-nitrogen burner to meet the low-nitrogen emission requirement, and the old boiler is directly replaced to meet the emission requirement.

At present, the known gas boiler burner is a relatively mature combustion technology, European and American low-nitrogen burner brands occupy the mainstream market in China, and some Chinese low-nitrogen burner brands gradually appear after 2015. Commonly used burners consist essentially of: the system comprises an air supply system (blower), a fuel system (natural gas), an electric control system, an ignition system and a detection system.

Generally, a stable ultra-low nitrogen burner head system is the direction in which each burner manufacturer is struggling. The prior known ultra-low nitrogen combustion head mainly comprises a full-premixing surface combustion head and a diffusion type low nitrogen combustion head, and the diffusion type low nitrogen combustion head mainly comprises two types: a diffusion type low-nitrogen combustion head and a front premixing diffusion type low-nitrogen combustion head. Through years of research and discovery of the applicant, the existing combustion heads respectively have the following characteristics:

full-premixing surface combustion head

The full-premixing surface combustion head, as disclosed in fig. 1, comprises a motor 1 ', a mixer 2' and a combustion head 3 ', wherein gas and air are respectively injected into the mixer 2' (metal barrel) through pipelines, and after colliding, pressurizing and premixing in the mixer 2 ', the gas and the air are effused from a plurality of tiny pores around the mixer 2'. The combustion flame is then formed on the surface of the metal felt on the outer layer of the mixer 2'. The advantages are that: the requirement on gas pressure is not high, the gas can be matched with various hearths, the premixing is uniform, the combustion is sufficient, and the NOX emission is less than or equal to 30mg/m 3. At present, the boiler is used more on a small-tonnage boiler.

The disadvantages are as follows:

1. after the full-premixing surface combustion head is combusted for a long time, dust in the air and combustion carbon deposition including oxides of the metal felt can block small holes on the periphery of the metal barrel, so that a mixed gas outlet is blocked, and flame deflagrates in the metal barrel to cause explosion accidents of the metal barrel. The existing improvement mode is to reduce the blocking probability by increasing the filtering measures (air and fuel gas), but the air filter is blocked after being used for a long time, the ventilation quantity is reduced if the air filter is not cleaned in time, the oxygen supply quantity is insufficient, the nitrogen oxide emission is influenced if the ventilation quantity is not cleaned in time, and accidents occur if the nitrogen oxide emission is serious.

Diffusion type low-nitrogen burner

2.1 pure diffusion type low-nitrogen burner

The pure diffusion type low-nitrogen combustion head is characterized in that a plurality of gas and air pipelines are arranged at the front end of the combustion head and are sprayed into a hearth through pressure to form premixing in the hearth, and the pure diffusion type low-nitrogen combustion head can be made into layered and sectional combustion. The aim of low nitrogen emission needs an auxiliary means of FGR (flue gas recirculation), about 20-25% of low-temperature flue gas returns to a hearth through a flue gas circulating pipeline, and the aim of reducing NOX is fulfilled.

The disadvantages are as follows:

1. the requirement on the fuel pressure is high, partial transformation areas cannot be boosted, and transformation is difficult.

2. The requirement on the size of a hearth is high when the boiler is reconstructed, and the hearth cannot be enlarged by an old boiler. Many boilers which are just used for two or three years are forced to be changed, and the enterprise burden is increased.

3. The newly-built boiler requires enlarging a hearth and increases the manufacturing cost of the boiler.

4. Under the condition that NOX is less than or equal to 30mg/m3, an FGR (flue gas recirculation) means is needed for assistance, and the FGR means can generate acidic condensed water to enter a hearth, so that the heat efficiency of the boiler is reduced, a combustor and the hearth are corroded, and the service life of the boiler is reduced.

5. When some users are found to close the FGR valve, the stealing discharge can be stolen.

6. The condensed water generated by FGR in extremely cold areas can be rapidly condensed into ice blocks to block the inlet of a fan, so that the phenomenon of furnace shutdown is caused. Or partial ice blocks are sucked into the fan to damage the impeller of the fan, so that the performance of the equipment is unstable, the maintenance rate is increased, and the service life of the equipment is shortened.

7. The air and the fuel gas are not mixed fully and uniformly, the combustion is incomplete, and the oxygen content is higher. The method has the defects that local high-temperature points exist, debugging is difficult, NOx emission is less than or equal to 30mg/m3 and can only be limited to a certain detection point, and the NOx emission is less than or equal to 30mg/m3 stably in the whole process.

2.2 Pre-mixing diffusion type low-nitrogen burner

The front premixing diffusion type low-nitrogen combustion head is characterized in that partial premixing gas is made in advance at the air inlet section of the combustor and then is injected into a hearth for combustion in a mode of combining a diffusion disc and a pipeline. The aim of low nitrogen emission needs an auxiliary means of FGR (flue gas recirculation), about 15-20% of low-temperature flue gas is returned to a hearth through a flue gas circulating pipeline, and the mode can partially reduce oxygen content and reduce NOx generation.

The disadvantages are as follows:

1. the technology has the advantages that the section part of the gas premixing device is added, the combustor body (heavy) needs to be enlarged, and the manufacturing cost is also increased.

2. Because of the partial gas premixing device, the tempering phenomenon occurs when the gas pressure is unstable.

3. The requirement on the size of a hearth is high when the boiler is reconstructed, and the hearth cannot be enlarged by an old boiler. Many boilers which are just used for two or three years are forced to be changed, and the enterprise burden is increased.

4. The newly-built boiler requires enlarging a hearth and increases the manufacturing cost of the boiler.

5. Under the condition that NOX is less than or equal to 30mg/m3, an FGR (flue gas recirculation) means is needed for assistance, and the FGR means can generate acidic condensate water to enter a hearth, so that the heat efficiency of the boiler is reduced, a combustor and the hearth are corroded, and the service life of the boiler is reduced;

6. when some users are found to close the FGR valve, the FGR valve can be stolen and released;

7. the condensed water generated by FGR in extremely cold areas can be rapidly condensed into ice blocks to block the inlet of a fan, so that the phenomenon of furnace shutdown is caused. Or partial ice blocks are sucked into the fan to damage the impeller of the fan, so that the performance of the equipment is unstable, the maintenance rate is increased, and the service life of the equipment is shortened.

In view of the combination of the two combustion modes, the method has a plurality of defects, and the aim of low nitrogen is achieved mainly by sacrificing energy consumption. Is not a 'low nitrogen, energy-saving' product in the true sense.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a gas molecule collision diffusion premixing low-nitrogen combustion head, which enables first gas sprayed from a central pipeline to be in strong collision with second gas sprayed from a first annular layer pipeline through reasonably arranging the central pipeline (conveying the first gas), the first annular layer pipeline (conveying the second gas) and the second annular layer pipeline (conveying the first gas), so that the first gas and the second gas are fully premixed, a first mixed gas is obtained, the first mixed gas can be in strong collision with the first gas sprayed from the second annular layer pipeline, the full premixing of the first gas and the second gas is realized, a local high-temperature point is avoided during combustion, and the generation of low-nitrogen oxide is effectively reduced.

In order to achieve the technical purpose, the invention adopts the following technical scheme:

a gas molecule collision diffusion premixing low-nitrogen combustion head comprises a combustion head body, wherein the combustion head body is provided with a central pipeline, a plurality of first annular layer pipelines, a plurality of second annular layer pipelines and an annular flame forming area; wherein:

the central pipeline is arranged along the central line of the combustion head body;

each first annular layer pipeline in the plurality of first annular layer pipelines is arranged on the first annular layer at the periphery of the central pipeline; each second annular layer pipeline in the plurality of second annular layer pipelines is arranged on the second annular layer at the periphery of the central pipeline;

the annular flame forming area is annularly arranged on the periphery of the central pipeline; the first annular layer and the second annular layer are sequentially arranged between the central pipeline and the annular flame forming area;

each first annular layer of pipelines is externally tangent to the central pipeline, and each first annular layer of pipelines is externally tangent to one second annular layer of pipelines; the circle center of each first annular layer pipeline, the circle center of a second annular layer pipeline externally tangent to the first annular layer pipeline and the circle center of the central pipeline are collinear;

the central pipeline is provided with a hole injection area a at two sides of the tangent position of each first annular layer pipeline; each first annular layer pipeline is provided with a hole injection area b at a corresponding position; hole injection areas c are arranged on two sides of each second annular layer pipeline at the position tangent to the first annular layer pipeline; the hole injection area a, the hole injection area b and the hole injection area c are provided with a plurality of injection holes;

the first gas jetted from the hole jet area a can collide with the second gas jetted from the hole jet area b for premixing to form a primary mixed gas capable of flowing towards the annular flame forming area; the primary mixed gas flowing towards the annular flame forming area can collide with the third gas sprayed from the hole spraying area c for premixing to form secondary mixed gas capable of continuously flowing towards the annular flame forming area; the secondary mixture can be combusted in the annular flame forming zone.

Furthermore, the annular flame forming area comprises a plurality of flame adjusting plates which are obliquely arranged, and a gap is formed between every two adjacent flame adjusting plates; each flame adjusting plate is made of a breathable material with a through hole in the plate surface.

Furthermore, the flame adjusting plates are arranged in a strip shape, the long ends of the flame adjusting plates are arranged along the length extension direction of the combustion head body, the short ends of the flame adjusting plates are obliquely arranged relative to the length extension direction of the combustion head body, and the inclination angle of the flame adjusting plates is smaller than 90 degrees.

Furthermore, the cross section of the flame adjusting plate is arranged in an arc shape or a corrugated shape and is fixedly arranged on a fixed seat of the combustion head body through a fixed rod; and the flame adjusting plate is made of a metal fiber sintered plate or an open pore metal plate.

Further, the first annular layer pipeline and/or the second annular layer pipeline are cylindrical pipes or adopt spring-type wound pipelines or S-shaped pipes or non-square-shaped pipelines; when the first annular layer pipeline and/or the second annular layer pipeline are non-character-shaped pipelines, each branch pipe of the non-character-shaped pipelines is provided with an injection hole.

Further, the cross-sectional shape of the central pipeline, the first annular layer pipeline and/or the second annular layer pipeline is circular, oval or polygonal.

Further, the injection hole is a tapered hole with gradually changed aperture.

Further, the hole injection zone a, the hole injection zone b and/or the hole injection zone c are micro-hole injection tapered zones in which the number of injection holes is gradually changed along the length extension direction of the combustion head.

Further, the opening angle of the injection holes of the first annular layer pipeline and/or the second annular layer pipeline is 45 degrees inclined towards the central pipeline; and the aperture of the jet hole is between 3mm and 5 mm.

Another technical object of the present invention is to provide a combustion apparatus having the above-mentioned gas molecule collision diffusion premixing low-nitrogen burner, including a blower, a gas pipe, an adapter and a burner body; the air blower is characterized in that the adapter comprises a first gas adapter tube, a second gas adapter tube and an air adapter tube which are coaxially arranged, and the center line of the adapter and the center line of the air outlet of the air blower are arranged in a collinear manner;

the first gas adapter tube is arranged along the middle position of the adapter, an inlet of the first gas adapter tube is arranged on the side wall and communicated with an outlet of the gas tube, and an outlet of the first gas adapter tube is butted with a central pipeline of the combustion head body; the air connecting pipe is an annular pipeline and is arranged between the first fuel gas connecting pipe and the second fuel gas connecting pipe, one end of the air connecting pipe is communicated with an air outlet of the air blower, and the other end of the air connecting pipe is butted with the first annular layer of the combustion head body; the second gas adapter is annularly arranged and located on the outer side of the air adapter, an inlet of the second gas adapter is formed in the side wall and communicated with the gas pipe through a branch pipe, and the other end of the second gas adapter is butted with the second annular layer of the combustion head body.

According to the technical scheme, compared with the prior art, the invention has the following advantages:

1. according to the invention, the first annular layer pipeline and the second annular layer pipeline are arranged on the periphery of the central pipeline, so that the combustion head body can form a plurality of mutually independent premixing areas on the periphery of the central pipeline along the radial direction, and the normal work of other areas cannot be influenced if one premixing area cannot work normally due to faults in the combustion process.

2. According to the first annular layer pipeline and the central pipeline, hole injection areas (which can be symmetrical or asymmetrical) are arranged on two sides of the tangent position of the first annular layer pipeline and the central pipeline, wherein a hole injection area a is arranged on the central pipeline, and a hole injection area b is arranged on the first annular layer pipeline, so that gas sprayed by each injection hole of the hole injection area a can collide with gas sprayed by each injection hole of the hole injection area b strongly, and the gas are premixed fully and uniformly to form primary mixed gas which can flow towards an annular flame forming area; the primary mixed gas is fully and uniformly premixed through the strong clash of the gas sprayed by each spray hole of the hole spray areas c arranged on the two sides of the tangent position of the first annular layer pipeline and the second annular layer pipeline by the second annular layer pipeline, and the secondary mixed gas which can still flow towards the annular flame forming area is formed.

Therefore, the secondary mixed gas can be combusted at the position close to the annular flame forming area after being ignited by the ignition ring arranged at the root part of the combustion head body, and the fuel gas and the air can be fully premixed, so that no local high-temperature point exists during combustion, and the generation of nitrogen oxides can be effectively and remarkably reduced.

Drawings

FIG. 1 is a schematic structural diagram of a fully premixed low-nitrogen combustion device;

FIG. 2 is a schematic structural diagram of a gas molecular collision diffusion premixing low-nitrogen combustion device according to the present invention;

FIG. 3 is a schematic view of the burner head of FIG. 2 according to the present invention;

FIG. 4 is an enlarged schematic view of section A of FIG. 3 (which illustrates impingement mixing between the gas streams exiting the respective stages of the pipeline);

FIG. 5 is a schematic diagram of a cylindrical first annular layer pipe or a cylindrical second annular layer pipe;

FIG. 6 is a schematic structural view of an S-shaped first loop pipe or second loop pipe;

FIG. 7 is a schematic view of a non-rectangular first or second annular pipe configuration;

in FIGS. 1-3: 1. a blower; 2. a gas pipe; 3. an adapter; 31-a first gas adapter tube; 32-a second gas transfer tube; 33-air connection pipe; 4-1, a burner body; 4-2, a central pipeline; 4-2-1, orifice jet zone a; 4-3, a first annular layer pipeline; 4-3-1, a hole injection zone b; 4-4, a second annular layer pipeline; 4-4-1, orifice jet zone c; 4-5, flame adjusting plate; 4-6, fixing a rod; 4-7, primary mixed gas; 4-8, secondary mixed gas; 41-branch pipe; 42-main tube.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The relative arrangement of the components and steps, expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may also be oriented in other different ways (rotated 90 degrees or at other orientations).

As shown in fig. 2 to 7, the gas molecule collision diffusion premixing low-nitrogen combustion head of the present invention comprises a combustion head body, wherein the combustion head body is provided with a central pipeline, a plurality of first ring layer pipelines, a plurality of second ring layer pipelines, and an annular flame forming region; wherein:

the central pipeline is provided with a hole injection area a at two sides of the tangent position of each first annular layer pipeline; each first annular layer pipeline is provided with a hole injection area b at a corresponding position; hole injection areas c are arranged on two sides of each second annular layer pipeline at the position tangent to the first annular layer pipeline; the hole injection area a, the hole injection area b and the hole injection area c are all provided with a plurality of injection holes.

In the invention, the central pipeline is an air micropore jet main pipeline (made of stainless steel high-temperature resistant pipe), wherein air is conveyed. The jet holes of the hole jet area a are arranged at the position close to the root part of the first annular layer pipeline and can impact and jet towards the root part of the first annular layer pipeline. Therefore, the air flow columns flowing out of the hole injection area a can be scattered, and the air flow columns are quickly diffused into more dispersed air molecules, so that the upward multi-directional capture of the gas molecules is facilitated. The gas can not be directly blown against the middle, so that the flow rate of the mixed gas can be controlled, and the phenomenon that flame is blown off due to false drifting caused by too high flow rate is prevented.

The first annular layer pipeline is a gas micropore injection pipeline (made of a stainless steel high-temperature resistant pipe). The angle of the air outlet is 45 degrees downwards, so that the fuel gas is sprayed downwards and forms strong collision with the air from the central pipeline, the fuel gas can be diffused in multiple directions and dispersed into smaller fuel gas molecules, and the smaller fuel gas molecules can be conveniently captured by the air molecules. In addition, the concentration difference of the fuel can also generate driving force to diffuse to the periphery, so that the premixing effect with air is further enhanced, and the first premixing is formed.

The second annular layer pipeline is a secondary air injection pipeline (made of stainless steel high-temperature resistant pipes), and the opening angle is 45 degrees downwards. Thus, the secondary air is injected downwards to form strong collision with the primary premixed gas and diffuse in multiple directions. At this time, the gas molecules are basically captured by the air molecules, and the effect of complete premixing is achieved.

Therefore, the combustion head body can form a plurality of mutually independent premixing areas which are similar to a cone shape (the pipe diameter of the first annular layer pipe is larger than that of the second annular layer pipe) along the radial direction on the periphery of the central pipe, and the first gas jetted from the hole jetting area a can collide with the second gas jetted from the hole jetting area b for premixing to form primary mixed gas which can flow towards the annular flame forming area; the primary mixed gas flowing towards the annular flame forming area can collide with the third gas sprayed from the hole spraying area c for premixing to form secondary mixed gas capable of continuously flowing towards the annular flame forming area; the secondary mixture can be combusted in the annular flame forming zone.

The aperture of the injection holes of the hole injection area a, the hole injection area b and the hole injection area c is between 3mm and 5 mm.

The annular flame forming area comprises a plurality of flame adjusting plates which are obliquely arranged, and a gap is formed between every two adjacent flame adjusting plates; each flame adjusting plate is made of a semi-permeable and microporous material, such as a metal fiber sintered plate or a perforated metal plate. The flame adjusting plates are arranged in a strip shape, the long ends of the flame adjusting plates are arranged along the length extending direction of the combustion head body, the short ends of the flame adjusting plates are obliquely arranged relative to the length extending direction of the combustion head body, and the inclination angle of the short ends is smaller than 90 degrees. The flame adjusting plate is fixedly arranged on the fixed seat of the combustion head body through the fixed rod.

In other words, the annular flame forming area is a flame combustion area of the semi-open type fish scale adjusting plate. (the material is a refractory metal fiber sintered plate, a high-temperature resistant metal perforated plate, a high-temperature resistant ceramic fiber plate and a cordierite perforated plate). The device can intercept the mixed gas, further enhance the premixing effect and prevent the flame-off phenomenon. The angle of the adjusting plate is adjusted through the servo motor, the flame spraying angle can be adjusted, and the flame height is controlled.

The flame-regulating plate is a metal fiber plate and the premixed gas can form a free-burning zone on the regulating plate or at the opening. The adjusting plate is arranged in a semi-open type fish scale shape, and a deflagration accident can not happen without a closed area. In addition, the adjusting plate is semi-movable, when mixed gas below the adjusting plate impacts the adjusting plate during combustion, the adjusting plate can slightly vibrate, impurities and carbon deposition in the gas can be conveniently shaken off, the device is not easy to block, and the service life of the device is prolonged.

The first annular layer pipeline and/or the second annular layer pipeline can be a cylindrical pipe as shown in fig. 5, or an S-shaped pipe as shown in fig. 6, or a spring-type wound pipeline or a non-square pipe as shown in fig. 7; when the first annular layer pipeline and/or the second annular layer pipeline are non-square pipelines, gas is input from a main pipe 42 of the non-square pipeline and then is output from an injection hole arranged on each branch pipe 41 of the non-square pipeline. The cross section of the central pipeline, the first annular layer pipeline and/or the second annular layer pipeline is circular, oval or polygonal. The jet hole is a tapered hole with gradually changed aperture. The hole injection zone a, the hole injection zone b and/or the hole injection zone c are micropore injection conical areas with the number of injection holes gradually changed along the length extension direction of the combustion head. The opening angle of the injection holes of the first annular layer pipeline and/or the second annular layer pipeline is 45 degrees inclined towards the central pipeline.

In addition, the central pipeline of the invention can also be used for conveying fuel gas, in this case, the first annular layer pipeline is used for conveying air, and the second annular layer pipeline is used for conveying fuel gas. In summary, the type of gas transported in the first annulus pipe needs to be inconsistent with the type in the central pipe and the second annulus pipe.

Another technical object of the present invention is to provide a combustion apparatus with the above combustion head, which comprises a blower, a gas pipe, an adapter and a combustion head body; the adapter comprises a first gas adapter tube, a second gas adapter tube and an air adapter tube which are coaxially arranged, and the center line of the adapter and the center line of the air outlet of the air blower are arranged in a collinear manner;

According to the technical scheme, the scheme has the following advantages:

1. the technology is mainly characterized in that the metal barrel which is the biggest potential safety hazard in the original surface combustion device is not existed. The explosion accident in the metal barrel is fundamentally avoided.

2. The molecular clash premixing mode is adopted, a metal barrel pressure overflow mode without a surface combustion device is omitted, and low-pressure fuel gas can be combusted. Meanwhile, the problem that the pressure of the natural gas is not high in the boiler transformation project and cannot be transformed is solved, and the backfire accident is avoided.

3. The annular flame forming area is made into a flame adjusting plate by using a semi-permeable and microporous metal fiber sintered plate or a perforated metal plate, and a semi-open fish scale arrangement mode is adopted, so that the problem of blockage is effectively solved, and the occurrence of deflagration accidents is avoided.

4. High-pressure fuel gas injection is not needed, and the problem that the diffusion type combustor has higher requirements on the fuel gas pressure is solved.

5. The high-pressure air injection is not needed, a fan with lower power can be configured, and the power consumption is reduced.

6. The flame shape is adjustable, and the transformation project can match various hearths. The ultra-low emission can be achieved by directly replacing the combustor of the boiler without increasing a hearth or replacing a boiler.

7. The flame shape can be adjusted, the newly-built boiler does not need to enlarge a hearth, and the manufacturing cost of the boiler is reduced.

8. No FGR means is needed for assistance, and no low-temperature flue gas backflow exists. The problem of condensate water and low temperature flue gas get into furnace, reduce boiler thermal efficiency is solved, reach energy-conserving purpose.

9. No FGR means is needed for assistance, no condensed water exists, and the problems that acidic condensed water corrodes a combustor and a hearth and the service life of a boiler is shortened are solved.

10. Without the aid of FGR means, there is no smoke circulation duct. The problem of partial user close FGR pipeline valve, steal the arranging secretly is solved.

11. FGR means is not required for assistance, and no condensed water is generated. The problem of blocking due to freezing of the condensate water at the extremely cold temperature is solved. Meanwhile, the problem that the impeller is damaged due to the fact that condensed water ice cubes are mixed into the fan is solved. The maintenance rate is reduced, and the service life of the equipment is prolonged.

12. And (3) uniformly premixing by adopting a molecular formula collision mode. Solves the problems of insufficient premixing, incomplete combustion, high oxygen content and local high temperature point in a diffusion combustion mode.

13. The problem of tempering in a pre-mixing diffusion combustion mode is solved without pre-mixing.

From the above, it can be seen that: the combustion head is not greatly different from the original surface combustion head in the appearance, and the internal premixing mode and the mixed gas overflowing mode are essentially different. The combustion technology provided by the scheme solves various technical pain points of old burners in the current market at one stroke. The large-scale boiler adopts a multi-station arrangement method, the fire arrangement is not interfered with each other, the temperature of the hearth is more uniform, and the thermal efficiency of the boiler is improved. The technology also solves the problem of reducing atmospheric pollutants; the problem that the combustion efficiency is not improved can not be met at the same time. The burner is a real 'low-nitrogen and energy-saving' product.

Taking a 6-ton combustion head as an example, the length of a single fuel gas injection pipeline needs 100 centimeters, and 8 fuel gas injection pipelines are needed in total.

The area needing to be perforated is 25 openings per square centimeter, 100 centimeters and 2 side openings, and 5000 fine spray small holes are formed in a single gas pipeline. 40000 fuel gas micro-injection pores are formed in a single 5000-micro-pore pipeline =6 tons of fuel gas pipelines.

The original surface combustion device has only about 4 gas injection pipes, and the nozzle of the scheme reaches 40000 tiny holes. A single air duct is also perforated with 2 times 2 ring layers in the same manner, so that the total number of perforations in the air duct can reach 160000.

The fuel and the air are sprayed through the dense and uniformly crossed distributed tiny pores, strong collision is formed during spraying, the fuel and the air are quickly diffused and fully premixed, and combustion is uniformly distributed on the surface of a flame forming area, so that local high-temperature points cannot be formed. The premixing is full, the combustion net rate is higher, the oxygen content can be effectively reduced, and the emission of NOX can be effectively reduced.

Claims

1. A gas molecule collision diffusion premixing low-nitrogen combustion head comprises a combustion head body, and is characterized in that the combustion head body is provided with a central pipeline, a plurality of first annular layer pipelines, a plurality of second annular layer pipelines and an annular flame forming area; wherein:

an annular area between the central pipeline and the annular flame forming area is divided into a plurality of mutually independent premixing areas along the radial direction through each first annular layer pipeline and each second annular layer pipeline;

2. The gas molecule collision diffusion premixing low-nitrogen combustion head of claim 1, wherein the annular flame forming zone comprises a plurality of flame adjusting plates which are obliquely arranged, and a gap is formed between two adjacent flame adjusting plates; each flame adjusting plate is made of a breathable material with a through hole in the plate surface.

3. The gas molecular collisional diffusion premixing low-nitrogen combustion head as claimed in claim 2, wherein said flame adjustment plates are provided in an elongated shape, the long end of each flame adjustment plate is arranged along the length extension direction of the combustion head body, the short end is arranged obliquely with respect to the length extension direction of the combustion head body, and the inclination angle is less than 90 °.

4. The gas molecule collision diffusion premixing low-nitrogen combustion head as claimed in claim 2 or 3, wherein the flame adjusting plate is arranged in a circular arc or corrugated shape in cross section and is fixedly mounted on the fixing seat of the combustion head body through a fixing rod; and the flame adjusting plate is made of a metal fiber sintered plate or an open pore metal plate.

5. The gas molecule collision diffusion premixing low-nitrogen combustion head of claim 1, wherein the first annular layer pipeline and/or the second annular layer pipeline is a cylindrical pipe or a spring type winding pipeline or an S-shaped pipe or a non-square-shaped pipeline; when the first annular layer pipeline and/or the second annular layer pipeline are non-character-shaped pipelines, each branch pipe of the non-character-shaped pipelines is provided with an injection hole.

6. The gas molecular collision diffusion premixing low-nitrogen combustion head of claim 1, wherein the cross-sectional shape of the central pipe, the first annular layer pipe and/or the second annular layer pipe is circular, oval or polygonal.

7. The gas molecular collision diffusion premixing low nitrogen combustion head according to claim 1, wherein the injection holes are tapered holes with gradually changed hole diameters.

8. The gas molecular collision diffusion premixing low-nitrogen combustion head of claim 1, wherein the hole injection zone a, the hole injection zone b and/or the hole injection zone c are micropore injection conical areas with gradually changed injection hole numbers along the length extension direction of the combustion head.

9. The gas molecular collision diffusion premixing low-nitrogen burner head of claim 1, wherein the opening angle of the injection holes of the first annular layer pipe and/or the second annular layer pipe is 45 degrees inclined towards the central pipe; and the aperture of the jet hole is between 3mm and 5 mm.

10. A combustion device with the gas molecular collision diffusion premixing low-nitrogen combustion head of claim 1, comprising a blower, a gas pipe, an adapter and a combustion head body; the air blower is characterized in that the adapter comprises a first gas adapter tube, a second gas adapter tube and an air adapter tube which are coaxially arranged, and the center line of the adapter and the center line of the air outlet of the air blower are arranged in a collinear manner;