CN112856416B - Semi-premixed internal circulation low nitrogen burner - Google Patents
Semi-premixed internal circulation low nitrogen burnerInfo
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- CN112856416B CN112856416B CN202110224750.7A CN202110224750A CN112856416B CN 112856416 B CN112856416 B CN 112856416B CN 202110224750 A CN202110224750 A CN 202110224750A CN 112856416 B CN112856416 B CN 112856416B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
- F23D14/04—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/26—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid with provision for a retention flame
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
- F23D14/46—Details
- F23D14/48—Nozzles
- F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23D—BURNERS
- F23D2900/00—Special features of, or arrangements for burners using fluid fuels or solid fuels suspended in a carrier gas
- F23D2900/14—Special features of gas burners
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
Abstract
The invention provides a semi-premixed internal-circulation low-nitrogen burner which comprises a refractory castable annular table, wherein an air channel is formed in the inner side of the refractory castable annular table, an internal combustion gas channel, an internal combustion gas-air mixing channel, a middle-layer gas ring, a middle-layer gas nozzle, an outer-layer gas channel, an outer-layer gas ring and an outer-layer gas nozzle. The arrangement of the internal combustion gas channel and the internal combustion gas-air mixing channel enables the fuel gas and the air to have the premixing effect. The middle-layer gas ring and the outer-layer gas ring are provided with fine gas nozzles, gas is sprayed out from the gas nozzles at high speed, the sprayed gas at high speed has higher kinetic energy and can entrain surrounding smoke, combustion air is not arranged in the area where the nozzles are positioned before the gas and air are mixed for combustion, the gas is decomposed into reducing substances CO, H+ and the like in an anoxic environment, the concentration of the gas is reduced to a certain extent, and therefore, the fuel calorific value is reduced, and when the gas and the air are combined for combustion, the combustion peak temperature is lower.
Description
Technical Field
The invention relates to the technical field of emission reduction of boilers and industrial furnaces, in particular to a semi-premixed internal-circulation low-nitrogen burner.
Background
Nitrogen oxides are an important push to cause acid rain and haze as a very harmful pollutant. The prior means for reducing nitrogen in the field of industrial boilers can be wholly divided into combustion method nitrogen reduction and flue gas post-treatment nitrogen reduction. The combustion method reduces nitrogen, namely reduces the generation amount of nitrogen oxides in the combustion process, and the flue gas post-treatment reduces nitrogen, namely treats the combusted flue gas to reduce the emission of nitrogen oxides. Compared with the flue gas post-treatment nitrogen reduction, the combustion method has the advantages of small investment, almost no extra operation cost, no secondary pollution and the like.
The national provinces require emissions of nitrogen oxides down to 30mg/Nm 3 from natural gas boilers. For relatively clean fuel with high heat value such as natural gas, most of nitrogen oxides generated during combustion are thermal nitrogen oxides, and for common and effective means for reducing nitrogen by the fuel combustion method, a flue gas recirculation technology and a full premix surface combustion technology are used together by diffusion combustion. The existing flue gas recirculation technology has the problems that condensed water is frequently generated in the application process, the existing flue gas recirculation has a certain influence on the thermal efficiency of a boiler to a greater or lesser extent, the vibration problem of the boiler is easily caused by uneven mixing of the added external circulation flue gas, the full-premixing surface combustion technology is that fuel and combustion-supporting air are premixed and then combusted, the technology has strict requirements on air distribution, the combustion stability is influenced by too much and too little oxygen, and even safety accidents occur.
Disclosure of Invention
To achieve the above and other related objects, the present invention provides a semi-premixed internal circulation low nitrogen burner, comprising a refractory castable annular table comprising opposite first and second surfaces, an air passage formed inside the refractory castable annular table, the air passage extending from the first surface to the second surface; the refractory castable ring comprises a first surface, an air channel, an inner gas-air mixing channel, a middle gas channel, an outer gas channel, a middle gas ring, middle gas nozzles, an outer gas channel, a middle gas nozzle and an outer gas ring, wherein the inner gas channel is arranged in the air channel, the inner gas-air mixing channel is arranged in the air channel, one end of the inner gas-air mixing channel is connected with the inner gas channel, the other end of the inner gas-air mixing channel extends to the downstream of the second surface, the middle gas channel is arranged in the refractory castable ring table, the middle gas channel extends from the first surface to the second surface, the middle gas ring is arranged on the second surface, surrounds the periphery of the gas ring, is communicated with the outer gas channel, is communicated with the middle gas channel and is in one-to-one correspondence with the middle gas channel, the middle gas nozzle is arranged on the middle gas ring and is communicated with the middle gas ring, the outer gas ring is arranged in the refractory castable ring table, and the outer gas ring is arranged on the outer gas ring.
The internal combustion air channels and the internal combustion air mixing channels are arranged in a one-to-one correspondence manner, and are arranged at intervals by taking the central line of the semi-premixed internal-circulation low-nitrogen burner as an axis.
Optionally, the internal combustion gas channel is a tapered channel, and a flow area of an end of the internal combustion gas channel, which is communicated with the internal combustion air mixing channel, is the smallest.
Optionally, the outlet of the internal combustion air mixing channel is a bending part, the bending part bends towards the direction of the refractory castable annular table, and the included angle between the bending part and the central line of the semi-premixed internal circulation low-nitrogen burner is 30-90 degrees.
Optionally, the middle layer gas spout and the outer layer gas spout are all a plurality of, and a plurality of middle layer gas spout is followed the circumference of middle layer gas ring is arranged, and a plurality of outer layer gas spout is followed the circumference of outer layer gas ring is arranged.
Optionally, the angle between the injection direction of the outer layer gas nozzle and the central line of the semi-premixed internal circulation low-nitrogen burner is-10 degrees to 60 degrees, and the angle between the injection direction of the middle layer gas nozzle and the central line of the semi-premixed low-nitrogen burner is 10 degrees to 70 degrees.
Optionally, the refractory castable annular table comprises a refractory castable annular table first layer, a refractory castable annular table second layer and a refractory castable annular table third layer which are sequentially overlapped from outside to inside, wherein the outer layer gas channel and the middle layer gas channel are both positioned in the refractory castable annular table first layer, and the spraying direction of the outer layer gas nozzle and the spraying direction of the middle layer gas nozzle face the refractory castable annular table second layer.
Optionally, the second surface of the second layer of the refractory castable annular table comprises an inclined surface and a horizontal surface, the inclined surface extends from the first layer of the refractory castable annular table to the horizontal surface of the second layer of the refractory castable annular table, the inclined angle of the inclined surface is 30-60 degrees, the second surface of the second layer of the refractory castable annular table is provided with a first annular groove, the second surface of the third layer of the refractory castable annular table is provided with a second annular groove, the second annular groove surrounds the periphery of the air channel, and the first annular groove surrounds the periphery of the second annular groove.
Optionally, the inner wall of the refractory castable annular table comprises an inclined inner wall such that the diameter of the opening of the air channel at the second surface is greater than the diameter of the opening at the first surface.
Optionally, the device further comprises a flame stabilizing disc, wherein the flame stabilizing disc is positioned at the downstream of the air channel, swirl blades and through holes are arranged on the flame stabilizing disc, the through holes are communicated with the air channel, the swirl blades are positioned at the periphery of the through holes, and the internal combustion gas-air mixing channel is positioned at the outer side of the flame stabilizing disc.
As described above, the semi-premixed internal circulation low-nitrogen burner has the following beneficial effects:
the arrangement of the internal combustion gas channel and the internal combustion gas-air mixing channel enables the fuel gas and the air to have the premixing effect.
The middle-layer gas ring and the outer-layer gas ring are provided with fine gas nozzles, gas is sprayed out from the gas nozzles at high speed, the sprayed gas at high speed has higher kinetic energy and can entrain surrounding smoke, combustion air is not arranged in the area where the nozzles are positioned before the gas and air are mixed for combustion, the gas is decomposed into reducing substances CO, H+ and the like in an anoxic environment, the concentration of the gas is reduced to a certain extent, and therefore the heat value of the fuel is reduced, and when the gas and the air are combined for combustion, the peak combustion temperature is lower, and the generation of nitrogen oxides can be effectively reduced in the above manner.
Most of the fuel gas is sprayed out from the fuel gas nozzles of the middle layer and the outer layer, and less premixed fuel gas is sprayed in the central area of the burner, so that the flame is hollow by the structure, namely, the root and the center of the whole flame are not generated, the temperature of the central area of the combustion can be effectively controlled, and the generation of thermal nitrogen oxides is reduced.
In the embodiment, the internal combustion gas channel is arranged in the air channel, the rear end of the internal combustion gas channel is connected with the internal combustion gas-air mixing device, and the rear end of the internal combustion gas channel is provided with a section of tapered opening and a section of straight section. Because of venturi effect at the necking position of the inner gas channel, the gas flow speed is high, a relatively negative pressure environment is formed, so that air in the air channel is easier to enter the inner gas-air mixing channel, and part of gas and air are premixed and combusted in the inner gas-air mixing channel. The premixed combustion temperature is more uniform, the combustion peak temperature is lower, and the generation of thermal nitrogen oxides can be effectively reduced. The premix gun can also play a role in stabilizing the main flame and provide a heat source for the outer fuel.
The middle layer gas nozzle and the outer layer gas nozzle respectively spray fuel to the combustion area at a certain angle, the structure avoids the excessive concentration of the fuel injection area, can effectively utilize the combustion space, ensures that the combustion temperature is more even, and reduces the generation of thermal nitrogen oxides.
The arrangement of the plurality of gas nozzles realizes multi-stage combustion, the injection of the plurality of gas nozzles enables the fuel injection to be more uniform, the fuel and the smoke can be better mixed by the injection of the plurality of gas nozzles, the heat value of the fuel is reduced as much as possible, the combustion speed is further effectively controlled, and the generation of thermal nitrogen oxides is reduced.
The air channel is a flaring device, the structure can enable air to diffuse into a combustion area, the combustion space is fully utilized, the furnace cavity fullness is better, and the combustion temperature is more even.
The flame stabilizing disc is placed at the downstream of the air channel, the negative pressure is formed at the rear end of the flame stabilizing disc by adding the flame stabilizing disc, and the formation of the negative pressure can scratch high-temperature smoke to realize internal circulation of the smoke. The internal circulation of the flue gas can reduce the temperature and oxygen content of a combustion area, thereby reducing the combustion peak value and further reducing the generation of thermal nitrogen oxides. The flame stabilizing disc is also provided with a swirl blade which can increase the kinetic energy of air in the radial direction and enhance the mixing of air and fuel gas.
The refractory castable annular table is divided into three layers, and the refractory castable of the protruding part of the three layers has the functions of heat accumulation and stable combustion, so that flame can be stably combusted under the oxygen content of 0-3%. And have annular groove in the second floor and the third floor of refractory castable annular table, annular groove can effectually increase the whirl of flue gas, can increase the mixing time and the effect of gas and flue gas, and then reduce the gas calorific value, control the production of thermal type nitrogen oxide.
Drawings
FIG. 1 is a top view of a semi-premixed, internal recycle low nitrogen combustor provided by the present invention.
FIG. 2 is a cross-sectional view of the semi-premixed, internal recycle low nitrogen combustor provided by the present invention along the AA direction in FIG. 1.
FIG. 3 is a gas flow diagram of a semi-premixed, internal recycle low nitrogen combustor provided by the present invention.
FIG. 4 is an enlarged schematic view of a middle layer gas ring and middle layer gas jets in a semi-premixed, internal recycle low nitrogen combustor provided by the present invention.
Fig. 5 is a schematic structural diagram of an internal combustion gas channel and an internal combustion gas-air mixing channel in the semi-premixed internal circulation low-nitrogen burner provided by the invention.
FIG. 6 is an enlarged schematic view of an outer gas ring and outer gas jets in a semi-premixed, inner recycle low nitrogen combustor provided by the present invention.
FIG. 7 is a partial cross-sectional view of a castable annular table in a semi-premixed, internal recycle low nitrogen combustor provided by the invention.
The element reference numerals are shown as 1, a refractory castable annular table, 101, a refractory castable annular table first layer, 102, a refractory castable annular table second layer, 1021 a first annular groove, 103, a refractory castable annular table third layer, 1031, a second annular groove, 2, an outer gas ring, 3, an outer gas nozzle, 4, a middle gas ring, 5, a middle gas nozzle, 6, an inner gas channel, 7, an inner gas-air mixing channel, 8, an air channel, 9, a flame stabilizing disc, 10, an inner gas-air mixing channel wall, 11, an outer gas channel and 12 middle gas channels.
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.
The preferred embodiments in the following description are by way of example only and other obvious variations will occur to those skilled in the art. The basic principles of the invention defined in the following description may be applied to other embodiments, variations, modifications, equivalents, and other technical solutions without departing from the spirit and scope of the invention.
It will be appreciated by those skilled in the art that in the present disclosure, the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "upstream," "downstream," etc. refer to an orientation or positional relationship based on that shown in the drawings, which is merely for convenience in describing the present invention and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore the above terms should not be construed as limiting the present invention.
As described above, the means for reducing nitrogen in the current industrial boiler field can be wholly divided into combustion method nitrogen reduction and flue gas post-treatment nitrogen reduction. The combustion method reduces nitrogen, namely reduces the generation amount of nitrogen oxides in the combustion process, and the flue gas post-treatment reduces nitrogen, namely treats the combusted flue gas to reduce the emission of nitrogen oxides. Compared with the flue gas post-treatment nitrogen reduction, the combustion method has the advantages of small investment, almost no extra operation cost, no secondary pollution and the like. For relatively clean fuel with high heat value such as natural gas, most of nitrogen oxides generated during combustion are thermal nitrogen oxides, and for common and effective means for reducing nitrogen by the fuel combustion method, a flue gas recirculation technology and a full premix surface combustion technology are used together by diffusion combustion. The full-premixing surface combustion technology, namely, the technology of premixing fuel and combustion-supporting air and then re-burning, has strict requirements on air distribution, and the stability of burning is influenced by too much and too little oxygen, even safety accidents occur.
Example 1
Referring to fig. 1 to 2, the invention provides a semi-premixed internal circulation low-nitrogen burner, which comprises a refractory castable annular table 1, wherein the refractory castable annular table 1 comprises a first surface and a second surface which are opposite, the first surface is a front end upstream surface, the second surface is a rear end downstream surface, an air channel 8 is formed inside the refractory castable annular table 1, the air channel 8 extends from the first surface to the second surface, an internal combustion gas channel 6 is positioned in the air channel 8 and extends from the first surface to the air channel 8, an internal combustion gas air mixing channel 7 is positioned in the air channel 8, one end of the internal combustion gas channel 6 is connected with the other end of the internal combustion gas channel 6, the other end of the internal combustion gas mixing channel extends to the downstream of the second surface, a middle layer gas channel 12 is positioned in the refractory castable annular table 1, the middle layer gas channel 12 extends from the first surface to the second surface, a gas ring 4 is positioned on the second surface, the air channel 8 surrounds the periphery, the air channel 12 surrounds the periphery, the middle layer channel is in the air channel 4 and is in communication with the outer layer 4, the gas ring 4 is in communication with the outer layer 11, the gas ring is in communication with the outer layer 4, and the gas ring is in communication with the outer layer 4, and is in communication with the outer gas ring 2.
In the semi-premix internal circulation low-nitrogen burner, the gas and the air are premixed through the arrangement of the internal gas channel 6 and the internal gas-air mixing channel 7. The middle-layer gas ring 4 and the outer-layer gas ring 2 are provided with fine gas nozzles, gas is ejected from the gas nozzles at high speed, the ejected high-speed gas has higher kinetic energy and can entrain surrounding smoke, combustion air is not arranged in the area where the nozzles are positioned before the gas and air are mixed for combustion, the gas is decomposed into reducing substances CO, H+ and the like in an anoxic environment, the concentration of the gas is reduced to a certain extent, and therefore, the heat value of the fuel is reduced, and when the gas and the air are combined for combustion, the peak combustion temperature is lower, and therefore, the generation of nitrogen oxides can be reduced. Most of the fuel gas is sprayed out from the fuel gas nozzles of the middle layer and the outer layer, and less premixed fuel gas is sprayed in the central area of the burner, so that the flame is hollow by the structure, namely, the root and the center of the whole flame are not generated, the temperature of the central area of the combustion can be effectively controlled, and the generation of thermal nitrogen oxides is reduced. The premixed combustion of the traditional nonmetal net method has no strict requirement on air distribution, and the stability of combustion is not affected due to too much and too little oxygen amount, so that safety accidents are avoided.
Example two
Referring to fig. 2 to 7 in conjunction with fig. 1, a semi-premixed internal circulation low-nitrogen burner is further provided in the present embodiment, and the semi-premixed internal circulation low-nitrogen burner in the present embodiment further includes the following structure compared to the semi-premixed internal circulation low-nitrogen burner in the first embodiment:
as an example, the plurality of internal combustion gas channels 6 and the plurality of internal combustion air mixing channels 7 are all arranged in a one-to-one correspondence manner, and the plurality of internal combustion gas channels 6 and the plurality of internal combustion air mixing channels 7 are circumferentially arranged by taking the central line of the semi-premixed internal circulation low-nitrogen burner as an axis.
As an example, the internal combustion gas passage 6 is a tapered passage, and the flow area of the end of the internal combustion gas passage 6 that communicates with the internal combustion air mixing passage 7 is smallest. Namely, the rear end of the inner gas channel 6 is a section of tapered opening and a section of straight section. Because of venturi effect at the necking of the inner gas channel 6, the gas flow speed is high, a relatively negative pressure environment is formed, so that air with higher pressure in the air channel 8 easily flows into the negative pressure area, the air in the air channel 8 easily enters the inner gas-air mixing channel 7, and partial gas and air are premixed and combusted in the inner gas-air mixing channel 7, so that a partial premixing effect is formed. The premixed combustion temperature is more uniform, the formation of a local high-temperature area is avoided, the combustion peak temperature is lower, and the generation of thermal nitrogen oxides can be effectively reduced. The premix gun can also play a role in stabilizing the main flame and provide a heat source for the outer fuel. And the air outside the internal combustion air-air mixing channel 7 has a certain cooling effect on the internal combustion air-air mixing channel wall 10, so that burning out of the internal combustion air-air mixing channel wall can be avoided.
By way of example, the internal combustion gas channel 6 and the internal combustion air mixing channel 7 form a premix assembly.
As shown in fig. 5, for example, the outlet of the internal combustion air mixing channel 7 is a bending portion, the bending portion is bent towards the direction of the refractory castable annular table 1, and an included angle α between the bending portion and the center line of the semi-premixed internal circulation low nitrogen burner is 30 ° to 90 °.
As an example, the middle-layer gas nozzles 5 and the outer-layer gas nozzles 3 are plural, the plural middle-layer gas nozzles 5 are arranged along the circumferential direction of the middle-layer gas ring 4, and the plural outer-layer gas nozzles 3 are arranged along the circumferential direction of the outer-layer gas ring 2. Specifically, the fuel is sprayed to the combustion area through the outer layer gas spray nozzles 3 and the middle layer gas spray nozzles 5, so that the fuel is sprayed in multiple stages, the multistage combustion is realized, the fuel and the flue gas are better mixed, the combustion reaction speed is effectively controlled, the combustion peak temperature is reduced, the combustion temperature is more average, the fuel is sprayed in different directions through the outer layer gas spray nozzles 3 and the middle layer gas spray nozzles 5, the combustion space is effectively applied, the flame is filled in a hearth, the furnace wall fully absorbs heat, the combustion peak temperature is reduced, the generation of nitrogen oxides is reduced, and the thermal efficiency is improved. The arrangement of the plurality of gas nozzles realizes multi-stage combustion, the injection of the plurality of gas nozzles enables the fuel injection to be more uniform, the fuel and the smoke can be better mixed by the injection of the plurality of gas nozzles, the heat value of the fuel is reduced as much as possible, the combustion speed is further effectively controlled, and the generation of thermal nitrogen oxides is reduced.
As an example, the angle γ between the injection direction of the outer layer gas nozzle 3 and the center line of the semi-premixed inner circulation low nitrogen burner is-10 ° to 60 °, as shown in fig. 6, and the angle β between the injection direction of the middle layer gas nozzle 5 and the center line of the semi-premixed low nitrogen burner is 10 ° to 70 °, as shown in fig. 4. The middle layer gas nozzle 5 and the outer layer gas nozzle 3 respectively spray fuel to the combustion area at a certain angle, the structure avoids the excessive concentration of the fuel injection area, can effectively utilize the combustion space, ensures that the combustion temperature is more even, and reduces the generation of thermal nitrogen oxides.
As an example, the refractory castable annular table 1 comprises a first refractory castable annular table layer 101, a second refractory castable annular table layer 102 and a third refractory castable annular table layer 103 which are sequentially stacked from outside to inside, the outer layer gas channel 11 and the middle layer gas channel 12 are both positioned in the first refractory castable annular table layer 101, and the spraying direction of the outer layer gas nozzle 3 and the spraying direction of the middle layer gas nozzle 5 are both towards the second refractory castable annular table layer 102.
Specifically, the refractory castable annular table 1 is divided into the first layer 101 of the refractory castable annular table, the second layer 102 of the refractory castable annular table and the third layer 103 of the refractory castable annular table, and the refractory castable has heat storage capacity, so that heat around the refractory castable annular table 1 is sufficient, enough ignition heat can be provided for fuel, and a strong combustion stabilizing effect is achieved. The heat accumulation area is increased by the protruding parts of the first layer 101, the second layer 102 and the third layer 103 of the refractory castable annular table 1, so that the heat accumulation capacity of the refractory castable annular table 1 is enhanced. The flame stabilizing structure enables the flame to burn stably at 0-3% oxygen content.
As an example, the second surface of the second layer 102 of the refractory castable annular table includes an inclined surface and a horizontal surface, the inclined surface extends from the first layer of the refractory castable annular table to the horizontal surface of the second layer of the refractory castable annular table, the inclined angle δ of the inclined surface is 30 ° to 60 °, as shown in fig. 7, the second surface of the second layer 102 of the refractory castable annular table is provided with a first annular groove 1021, the second surface of the third layer 103 of the refractory castable annular table is provided with a second annular groove 1031, the second annular groove 1031 surrounds the periphery of the air channel 8, and the first annular groove 1021 surrounds the periphery of the second annular groove 1031.
Specifically, as shown in fig. 3, no air exists radially outside the refractory castable annular table 1, so that only flue gas exists around the fuel gas sprayed out from the outer layer fuel gas nozzle 3 and the middle layer fuel gas nozzle 5, and the fuel is in an anoxic environment after being sprayed. The outer layer gas nozzle 3 and the middle layer gas nozzle 5 have smaller sizes, the speed of the gas passing through the outer layer gas nozzle 3 and the middle layer gas nozzle 5 is larger, the kinetic energy of the gas flow is larger, surrounding flue gas can be sucked into the gas flow, the first annular groove 1021 and the second annular groove 1031 can strengthen the vortex of the flue gas flow, and the gas is further cracked into reducing substances CO, H+ and the like while the gas and the flue gas are mixed. The structure can effectively dilute the fuel gas to a certain extent, thereby reducing the combustion peak temperature and reducing the generation of thermal nitrogen oxides.
As an example, the inner wall of the refractory castable annular table 1 comprises an inclined inner wall such that the diameter of the opening of the air channel 8 at the second surface is larger than the diameter of the opening at the first surface.
Specifically, the air channel 8 is a divergent port structure, the flow area in the gas flow direction is larger and larger, the structure can enable air to diffuse into the combustion area, the combustion space is fully utilized, the fire box flame fullness is better, the combustion temperature is more even, the generation of nitrogen oxides is reduced, and the heat efficiency of the furnace can be improved.
As an example, the device further comprises a flame stabilizing disc 9, wherein the flame stabilizing disc 9 is positioned at the downstream of the air channel 8, swirl blades and through holes are arranged on the flame stabilizing disc 9, the through holes are communicated with the air channel 8, the swirl blades are positioned at the periphery of the through holes, and the internal combustion air-air mixing channel 7 is positioned at the outer side of the flame stabilizing disc 9.
Specifically, the flame stabilizing disc 9 is arranged at the rear end of the air channel 8, and the center line of the flame stabilizing disc 9 is coincident with the center line of the semi-premixed internal circulation low-nitrogen burner. The addition of the flame stabilizing disc 9 blocks the air flow, so that negative pressure is formed at the rear end of the flame stabilizing disc, and the negative pressure can suck the smoke, thereby realizing the internal circulation of the smoke. The internal circulation of the flue gas can reduce the temperature and oxygen content of a combustion area, thereby reducing the combustion peak value and further reducing the generation of thermal nitrogen oxides. The flame stabilizing disc 9 is also provided with a swirl blade, the swirl blade can increase the kinetic energy of air in the radial direction, enhance the mixing of air and fuel gas, realize uniform combustion, form a central negative pressure and further roll smoking.
The invention combines the technical means of internal circulation of flue gas, staged combustion, semi-premixing, heat accumulation stable combustion and the like, and the hollow flame design can effectively reduce the combustion temperature, and can realize that the emission of nitrogen oxides is below 30mg/Nm 3 without using external circulation of flue gas and flameless combustion when burning relatively clean fuel with high heat value. The low-nitrogen burner has low-nitrogen combustion characteristics and better flame fullness in a hearth, and can improve the heat efficiency of the furnace.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the disclosure is not limited to the embodiments described in detail below, and that the embodiments described in the examples may be combined as appropriate to form other embodiments that will be apparent to those skilled in the art.
Claims (10)
1. The semi-premixed internal circulation low-nitrogen combustor is characterized by comprising a refractory castable annular table, a gas inlet pipe and a gas outlet pipe, wherein the refractory castable annular table comprises a first surface and a second surface which are opposite, an air channel is formed in the inner side of the refractory castable annular table, and the air channel extends from the first surface to the second surface; the refractory castable ring comprises a first surface, an air channel, an inner gas-air mixing channel, a middle gas channel, an outer gas channel, a middle gas ring, middle gas nozzles, an outer gas channel, a middle gas nozzle and an outer gas ring, wherein the inner gas channel is arranged in the air channel, the inner gas-air mixing channel is arranged in the air channel, one end of the inner gas-air mixing channel is connected with the inner gas channel, the other end of the inner gas-air mixing channel extends to the downstream of the second surface, the middle gas channel is arranged in the refractory castable ring table, the middle gas channel extends from the first surface to the second surface, the middle gas ring is arranged on the second surface, surrounds the periphery of the gas ring, is communicated with the outer gas channel, is communicated with the middle gas channel and is in one-to-one correspondence with the middle gas channel, the middle gas nozzle is arranged on the middle gas ring and is communicated with the middle gas ring, the outer gas ring is arranged in the refractory castable ring table, and the outer gas ring is arranged on the outer gas ring.
2. The semi-premixed inner circulation low-nitrogen burner of claim 1, wherein the plurality of internal combustion gas channels and the plurality of internal combustion gas-air mixing channels are arranged in a one-to-one correspondence manner, and the plurality of internal combustion gas channels and the plurality of internal combustion gas-air mixing channels are circumferentially arranged with a central line of the semi-premixed inner circulation low-nitrogen burner as an axis.
3. The semi-premixed inner circulation low nitrogen burner of claim 1, wherein said internal combustion gas passage is a tapered passage and a flow area of an end of said internal combustion gas passage communicating with said internal combustion gas-air mixing passage is minimized.
4. The semi-premixed and internal-circulation low-nitrogen burner of claim 1, wherein the outlet of the internal combustion air-air mixing channel is a bending part, the bending part is bent towards the refractory castable annular table, and an included angle between the bending part and the central line of the semi-premixed and internal-circulation low-nitrogen burner is 30-90 degrees.
5. The semi-premixed internal circulation low-nitrogen burner of claim 1, wherein the middle-layer gas nozzles and the outer-layer gas nozzles are multiple, the middle-layer gas nozzles are distributed along the circumferential direction of the middle-layer gas ring, and the outer-layer gas nozzles are distributed along the circumferential direction of the outer-layer gas ring.
6. The semi-premixed and internal circulation low nitrogen burner of claim 1, wherein the angle between the injection direction of the outer layer gas nozzle and the central line of the semi-premixed and internal circulation low nitrogen burner is-10-60 degrees, and the angle between the injection direction of the middle layer gas nozzle and the central line of the semi-premixed and internal circulation low nitrogen burner is 10-70 degrees.
7. The semi-premixed internal circulation low-nitrogen burner of claim 1, wherein the refractory castable annular table comprises a refractory castable annular table first layer, a refractory castable annular table second layer and a refractory castable annular table third layer which are sequentially overlapped from outside to inside, the outer layer gas channel and the middle layer gas channel are both positioned in the refractory castable annular table first layer, and the spraying direction of the outer layer gas nozzle and the spraying direction of the middle layer gas nozzle face the refractory castable annular table second layer.
8. The semi-premixed internal circulation low-nitrogen burner of claim 1, wherein the second surface of the second layer of the refractory castable annular table comprises an inclined surface and a horizontal surface, the inclined surface extends from the first layer of the refractory castable annular table to the horizontal surface of the second layer of the refractory castable annular table, the inclined angle of the inclined surface ranges from 30 degrees to 60 degrees, the second surface of the second layer of the refractory castable annular table is provided with a first annular groove, the second surface of the third layer of the refractory castable annular table is provided with a second annular groove, the second annular groove surrounds the periphery of the air channel, and the first annular groove surrounds the periphery of the second annular groove.
9. The semi-premixed, internally circulating low nitrogen burner of claim 1, wherein the inner wall of the refractory castable annular table comprises an inclined inner wall such that the diameter of the opening of the air channel at the second surface is greater than the diameter of the opening at the first surface.
10. The semi-premixed internal circulation low nitrogen burner of claim 1, further comprising a flame stabilizing disk, wherein the flame stabilizing disk is positioned at the downstream of the air channel, swirl vanes and through holes are arranged on the flame stabilizing disk, the through holes are communicated with the air channel, the swirl vanes are positioned at the periphery of the through holes, and the internal combustion air mixing channel is positioned at the outer side of the flame stabilizing disk.
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Effective date of registration: 20211213 Address after: 200433 room 13002-3, No. 188, Wudong Road, Yangpu District, Shanghai Applicant after: SHANGHAI SIFANG BOILER GROUP ENGINEERING SYSTEM Co.,Ltd. Applicant after: Shanghai bonasen Environmental Technology Co.,Ltd. Address before: 201901 room b1541, building 11, no.358, Meilin Road, Baoshan District, Shanghai Applicant before: Shanghai bonasen Environmental Technology Co.,Ltd. |
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