CN211876021U - Low-nitrogen condensation-preventing combustor and combustion system - Google Patents

Abstract

The utility model provides a low-nitrogen anti-condensation burner and combustion system, which comprises an outer tube, an inner tube and a waste gas suck-back structure, wherein one end of the outer tube is a fire outlet end, the other end is a gas inlet end, the gas inlet end is provided with a combustion-supporting gas interface, the inner tube penetrates into the outer tube, the inner tube is provided with a gas interface, the waste gas suck-back structure comprises a waste gas suck-back tube cover and a waste gas draft device, the waste gas suck-back tube cover is arranged on the outer tube, the waste gas suck-back hole is arranged on the outer tube, the waste gas draft device is connected with the waste gas suck-back tube cover, the waste gas draft device exhausts air, the waste gas which circles to the rear part of the fire outlet end after combustion is sucked to the waste gas suck-back tube cover and is transmitted into the fire outlet end of the outer tube, the waste gas which is transmitted back is mixed with the combustion-supporting gas which is guided into the outer tube, the gas which is, to reduce the temperature of the exhaust gas return hood. The low-nitrogen condensation-preventing combustor can slow down the corrosion speed and prolong the service life.

Description

Low-nitrogen condensation-preventing combustor and combustion system

Technical Field

The utility model relates to a low nitrogen condensation burner and combustion system are prevented.

Background

At present, in an industrial furnace, a burner is installed on a furnace body to heat in a hearth, a burner nozzle of the burner faces into the furnace body, combustion-supporting gas is input through a combustion-supporting pipe of the burner, fuel is input through a fuel pipe, and the combustion-supporting gas and the fuel are mixed at the burner nozzle and then ignited to burn, so that the heating is realized by burning flame in the hearth. The burner is positioned at a section outside the furnace body and close to the furnace body, and is easy to react with oxygen and water vapor in the air at high temperature to be corroded, so that the service life of the burner is shortened. In addition, the prior art adopts the flue gas recirculation mode, and the exhaust smoke outlet department that the waste gas circulates the back end of the pipe connection furnace and the combustor of furnace front end, and the waste gas circulates the back pipe very long, and exposes in external environment, when the external temperature is lower, or when the boiler suspends the use, easily forms the comdenstion water in the vapor in the intraductal waste gas, especially in northern winter, the vapor condensation of condensation is at the easy corrosion pipeline of pipe wall, often needs the maintenance to change the waste gas and circulates the pipe. Therefore, there is a need for improvement thereof.

Disclosure of Invention

In view of the above, the utility model provides a low nitrogen condensation burner is prevented to improve the life of combustor.

The utility model relates to a technical solution:

a low-nitrogen anti-condensation burner comprises an outer tube, an inner tube and a waste gas suck-back structure, wherein one end of the outer tube is a fire outlet end, the other end of the outer tube is a gas inlet end, the gas inlet end is provided with a combustion-supporting gas interface, the inner tube penetrates into the outer tube, the inner tube is provided with a gas interface, combustion-supporting gas led in by the outer tube and gas led in by the inner tube are mixed in the fire outlet end of the outer tube and then ignited to burn, the waste gas suck-back structure comprises a waste gas suck-back tube cover and a waste gas draft device, the waste gas suck-back tube cover is arranged on the outer wall of the fire outlet end of the outer tube and is provided with waste gas suck-back holes, the waste gas draft device is connected with the waste gas suck-back tube cover, the waste gas is sucked into the waste gas suck-back tube cover and then conveyed into the fire outlet end of the outer tube, the conveyed back waste gas is mixed with the combustion-supporting gas led in, the waste gas return suction pipe cover is internally burnt at the fire outlet end, and the periphery of the waste gas return suction pipe cover is sleeved with a cooling device so as to reduce the temperature of the waste gas return suction pipe cover.

Furthermore, the cooling device comprises a water storage device, and a water inlet pipe and a water outlet pipe which are respectively communicated with the water storage device, and cold water is injected into the water storage device from the water inlet pipe, so that heat exchange occurs between the cold water and the waste gas return suction pipe cover, and the temperature of the waste gas return suction pipe cover is reduced.

Furthermore, the water storage device is of a cylinder structure, and an annular water storage cavity is formed in the cylinder structure.

Furthermore, the water inlet pipe and the water outlet pipe are oppositely arranged on the water storage device.

Further, the waste gas resorption structure includes the waste gas back flow, and the waste gas back flow penetrates in the inner tube, and exhaust gas updraft ventilator passes through pipeline one end and is connected to waste gas resorption pipe cover, and the other end is connected with the waste gas back flow.

Further, the fire outlet end is provided with a combustion space section, the inner pipe barrel is provided with an air outlet end, the outer peripheral wall of the air outlet end is connected with a premixing pipe, and the other end of the premixing pipe extends to the combustion space section.

Further, the air outlet end of the inner tube extends to a position adjacent to the premixing tube, and the flue gas return pipe extends to a position adjacent to the combustion space section.

Furthermore, the waste gas resorption structure further comprises a heat exchanger, the heat exchanger is provided with a first air inlet interface and a first air outlet interface, a second air inlet interface and a second air outlet interface, the first air inlet interface is connected with the air outlet interface of the waste gas resorption pipe cover, the first air outlet interface is connected with the waste gas air extraction device, a combustion-supporting gas conveying device is connected to the second air inlet interface, and the second air outlet interface is connected to the combustion-supporting gas interface.

The utility model provides a combustion system, includes the furnace body and installs the combustor on the furnace body, and the furnace body has furnace, has seted up the burner hole on the front side oven of furnace body, and the top of furnace body is close to the rear side oven wall and is provided with the smoke window to supply the exhaust after the burning in the furnace, the combustor adopts low nitrogen anti condensation combustor, it is installed on the front side oven of furnace body, and the port of the play fire end of outer tube stretches into to furnace in.

The utility model discloses low-nitrogen anti-condensation burner establishes cooling device through overlapping in waste gas return pipe cover periphery to reduce the temperature of waste gas return pipe cover, thereby slow down the speed of corrosion, improve the life of combustor. Furthermore, the utility model discloses the combustor can avoid using completely in the tradition to be used for leading-in the waste gas circulation pipe to the combustor with cigarette window waste gas to the problem of waste gas circulation pipe because the condensation damages has been avoided. Furthermore, the utility model discloses low nitrogen anti-condensation burner has realized waste heat recovery and has recycled, has reached the high effect of heat recovery utilization ratio, and convenient to use has reduced the energy consumption with waste heat make full use of moreover.

Drawings

FIG. 1 is a schematic cross-sectional view of a low-nitrogen condensation preventing burner according to the present invention;

FIG. 2 is an enlarged view of a partial cross-sectional view of the low-nitrogen condensation preventing burner of the present invention;

FIG. 3 is a perspective view of the low-nitrogen energy-saving combustion system of the present invention;

FIG. 4 is a partial enlarged view of the low-nitrogen energy-saving combustion system of the present invention;

fig. 5 is a schematic view of a partial cross-section of the low-nitrogen energy-saving combustion system of the present invention.

Detailed Description

The technical solution in the embodiment of the present invention is clearly and completely described below with reference to the drawings in the embodiment of the present invention. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the scope of the invention.

Referring to fig. 1 and 2, the present invention provides a low-nitrogen anti-condensation burner, which comprises an outer tube 1, an inner tube 2 and a waste gas recycling structure 3, wherein the outer tube 1 is provided with a combustion-supporting gas port 11, the inner tube 2 penetrates into the outer tube 1, the inner tube 2 is provided with a gas port 21 for mixing combustion-supporting gas introduced from the outer tube 1 with gas introduced from the inner tube 2 at a fire outlet end and igniting the mixture for combustion, the waste gas recycling structure 3 comprises a waste gas recycling tube cover 31 and a waste gas draft device 32, the waste gas recycling tube cover 31 is disposed on the outer circumferential wall of the outer tube 1 and provided with a waste gas recycling hole 311, the waste gas draft device 32 is connected with the waste gas recycling tube cover 31, the waste gas is exhausted by the waste gas draft device 32, the waste gas is recycled to the rear of the fire outlet end after being combusted, the waste gas is sucked into the waste gas recycling tube cover 31 and is conveyed into the fire outlet end of the outer tube 1, and the recycled waste gas is mixed with the, The gas introduced into the inner pipe barrel 2 is mixed and combusted in the fire outlet end.

The periphery of the exhaust gas return pipe cover 31 is sleeved with the cooling device 9 to reduce the temperature of the exhaust gas return pipe cover 31 and slow down the corrosion speed of the exhaust gas return pipe cover 31. Cooling device 9 includes water receiver 91 and the inlet tube 92 and the outlet pipe 93 that are linked together with water receiver 91 respectively, through injecting cold water into water receiver 91 from inlet tube 92, takes place heat exchange between cold water and the waste gas resorption pipe cover 31, and cold water absorbs the heat and the temperature rise of waste gas resorption pipe cover 31 to flow out from outlet pipe 93, waste gas resorption pipe cover 31 is because of exothermic cooling, thereby slows down the corrosion speed of waste gas resorption pipe cover 31.

In this embodiment, the water reservoir 91 is a cylindrical structure, and an annular water storage cavity 94 is formed in the cylindrical structure so as to be sleeved on the outer peripheral surface of the exhaust gas suck-back pipe cover 31.

Preferably, the water inlet tube 92 and the water outlet tube 93 are oppositely disposed on the water reservoir 91 to improve the heat exchange rate.

It can be understood that the utility model discloses the combustor also can not set up waste gas resorption structure 3, and 1 periphery of outer tube is located to cooling device 9 covers to reduce the temperature of outer tube 1, slow down the speed of corrosion.

One end of the outer tube 1 is a fire outlet end, the other end of the outer tube is an air inlet end, the fire outlet end is used for spraying out burning flames, the outer tube has a burning space section 101, a port of the air inlet end is closed and only allows the inner tube 2 to pass through, and the outer peripheral wall of the air inlet end is provided with the combustion-supporting air interface 11 for connecting the combustion-supporting air conveying device 35 to input combustion-supporting air into the outer tube 1.

One end of the inner tube barrel 2 is an air outlet end, the other end is an air inlet end, the inner tube barrel 2 extends into the outer tube barrel 1 through the end wall of the air inlet end of the outer tube barrel 1, the air inlet end is exposed out of the outer tube barrel 1, the gas outlet end of the gas mixing pipe extends to the combustion space section 101 of the outer pipe barrel 1, the port of the gas inlet end of the inner pipe barrel 2 is closed, the gas interface 21 is arranged on the peripheral wall of the gas inlet end, the peripheral wall of the gas outlet end of the inner pipe barrel 2 is connected with a premixing pipe 4, the pipe diameter of the premixing pipe 4 is larger than the outer diameter of the inner pipe barrel 2 and smaller than the inner diameter of the outer pipe barrel 1, an inner end edge is formed at one end of the premixing pipe 4 and fixedly connected with the peripheral wall of the gas outlet end of the inner pipe barrel 2, the outer end edge is formed at the other end and fixedly connected, so that the combustion-supporting gas entering the outer tube 1 partially enters the premixing tube 4, the outer end edge is provided with a gas passing hole 42, so that the combustion-supporting gas entering the outer tube 1 partially enters the combustion space section 101 for combustion. Further, for the air current intensive mixing in combustion space section 101, the intensive combustion, cross gas pocket 42 and adopt spiral pore structure, and a plurality of gas pockets 42 of crossing adopt the same spiral direction, so, the combustion-supporting gas that gets into in combustion space section 101 from gas pocket 42 is the spiral wind, can improve the mixed effect, and the burning is abundant, and the flame outwards scurries farther from combustion space section 101, more is favorable to the furnace heating.

Part of the combustion-supporting gas is premixed with the fuel gas in the premixing pipe 4 and ignited, so that the ignition is not easy to extinguish, and then the combustion enters the combustion space section 101 and is fully mixed and combusted with the other part of the combustion-supporting gas entering the combustion space section 101.

It will be appreciated that an electric spark ignition device (not shown) is disposed within premix tube 4 and may ignite the premix gas within premix tube 4 by an electron splash spark.

It will be appreciated that in order to achieve adequate premixing of the combustion gases and the combustion air entering the pre-mixing tube 4, the end of the inner barrel 2 received within the pre-mixing tube 4 should not be too long, and preferably extends into the adjacent position of the pre-mixing tube 4, in this embodiment the inner barrel 2 extends substantially to the adjacent position of the pre-mixing tube 4 and slightly beyond.

The waste gas suck-back pipe cover 31 is in a pipe barrel shape, is sleeved on the outer peripheral wall of the fire outlet end of the outer pipe barrel 1, and comprises a barrel part and ring plates formed at two ends in the barrel part, wherein the ring plates are fixedly connected on the outer peripheral wall of the outer pipe barrel 1, and the ring plates in the same direction as the fire outlet end are provided with the waste gas suck-back holes 311 for the waste gas to enter the barrel part of the waste gas suck-back pipe cover 31; an air outlet interface 30 is arranged on the peripheral wall of the cylinder part, and the waste gas exhaust device 32 is connected with the air outlet interface 30 so as to guide out the waste gas in the cylinder part and convey the waste gas to the combustion space section in the outer pipe cylinder 1.

The exhaust gas suck-back structure 3 further comprises an exhaust gas return pipe 33, one end of the exhaust gas return pipe 33 penetrates from the closed end of the inner pipe barrel 2, penetrates out of the other end of the inner pipe barrel 2 and then extends to the combustion space section 101, and the other end of the exhaust gas return pipe is connected with the exhaust gas draft device 32 so that the exhaust gas draft device 32 can guide the combusted exhaust gas into the combustion space section 101 in the outer pipe barrel 1.

It will be appreciated that, preferably, to ensure that the premixed gas in the premix tube ignites well and does not extinguish easily after ignition, wastegate 33 passes through premix tube 4 to direct the flue gas into the combustion space section, otherwise wastegate 33 would extend into premix tube 4. Furthermore, a port of the inner tube 2 connected to one end of the pre-mixing tube 4 is provided with a conical wall fixedly connected to the periphery of the exhaust gas return pipe 33, and the conical wall is provided with air holes 22, so that air in the inner tube 2 can enter the pre-mixing tube 4 through the air holes 22.

The exhaust gas back suction structure 3 further comprises a heat exchanger 34, the heat exchanger 34 comprises a heat exchange box body and a heat exchange tube arranged in the box body, a first air inlet interface, a first air outlet interface, a second air inlet interface and a second air outlet interface are arranged on the heat exchange box body, the first air inlet interface is communicated with the heat exchange tube, the first air outlet interface is communicated with the heat exchange tube, so that air entering from the first air inlet interface flows out of the first air outlet interface after flowing through the heat exchange tube, and air entering from the second air inlet interface flows out of the second air outlet interface after flowing through the box body. First air inlet interface connection waste gas resorption pipe cover 31's interface 30 of giving vent to anger, first air-out interface connection waste gas updraft ventilator 32 to waste gas updraft ventilator 32 will follow the waste gas of suction in the waste gas resorption pipe cover 31 and carry through the heat exchanger, realize the heat transfer to waste gas. And, set up heat exchanger 34 before waste gas updraft ventilator 32, reduced the temperature in the waste gas that gets into waste gas updraft ventilator 32 to can protect waste gas updraft ventilator 32 not damaged by high temperature, otherwise the waste gas of high temperature directly gets into waste gas updraft ventilator 32, can damage waste gas updraft ventilator 32 easily, and waste gas updraft ventilator 32's motor burns out easily under the high temperature environment.

The heat transfer can carry out the heat transfer with the external combustion-supporting gas of carrying to combustion-supporting gas interface 11, specifically, a combustion-supporting gas conveyor 35 is connected to the second air inlet interface, and second air-out interface connection is to combustion-supporting gas interface 11, so, can pass through the heat exchanger heat transfer with the higher waste gas of temperature from the combustion-supporting gas of carrying, preheats the combustion-supporting gas of carrying, has fully utilized the heat energy of combustion-supporting gas, plays energy-conserving effect.

In addition, in order to facilitate the processing of the low-nitrogen anti-condensation burner, firstly, the inner tube 2, the waste gas reflux pipe 33, the end edges at two ends of the pre-mixing pipe 4 and the pre-mixing pipe 4 are integrally processed into a whole, then the inner tube 2 is installed on the outer tube 1, in order to facilitate the assembly of the inner tube 2 of the low-nitrogen anti-condensation burner and the outer tube 1, a first flange is formed at the periphery of the inlet end port of the outer tube 1, a second flange 7 is formed at the periphery wall of the inlet end of the inner tube 2, the inner tube 2 penetrates into the outer tube 1, and the two flanges are connected in alignment.

In addition, in order to facilitate the installation of the low-nitrogen condensation preventing burner to the boiler body, a flange 5 is formed on the outer periphery of the exhaust gas return pipe cover 31, so that the low-nitrogen condensation preventing burner can be easily fixed to the boiler body. The cooling device 9 is installed between the flange 5 and the outlet port 30 of the exhaust gas return pipe cover 31, and one end surface of the water reservoir 91 is fixed to the flange 5.

When the low-nitrogen anti-condensation burner is used, please refer to fig. 3 to 5 again, a combustion system includes a furnace body 6 and the low-nitrogen anti-condensation burner installed on the furnace body 6, the furnace body 6 has a furnace chamber, a fire nozzle hole 61 is opened on the front side furnace wall of the furnace body 6, the aperture of the fire nozzle hole 61 is approximately corresponding to or slightly larger than the outer diameter of the waste gas suck-back pipe cover 31, and the waste gas suck-back pipe cover 31 of the low-nitrogen anti-condensation burner can be sleeved in. The water inlet pipe 92 is connected to the lower side wall of the water receiver 91, and the water outlet pipe 93 is connected to the upper side wall of the water receiver 91, so that the heated water is easy to flow out from the water outlet pipe 93 of the upper side wall due to the density reduction, and the heat exchange rate is improved. The top end of the furnace body 6 is provided with a smoke window 62 adjacent to the rear furnace wall for discharging the waste gas in the combustion furnace. The low-nitrogen condensation-preventing burner is arranged on the front furnace wall of the furnace body 6, and the port of the fire outlet end of the outer tube 1 extends into the furnace chamber.

When the combustion system operates, the combustion-supporting gas conveying device 35 is started to convey combustion-supporting gas, the gas device (not shown) conveys gas, the combustion-supporting gas passes through the heat exchanger 34 and is conveyed into the outer tube 1 from the combustion-supporting gas connector, the gas is conveyed into the inner tube 2 from the gas connector, then the gas enters the premixing tube 4, part of the combustion-supporting gas enters the premixing tube 4 to be premixed with the gas, the premixed gas in the premixing tube 4 is ignited by the ignition device, flame is introduced into the combustion space section 101, the combustion-supporting gas is further supplemented into the combustion space section 101, the combustion-supporting gas and the premixed gas are fully combusted, the flame is sprayed into the hearth, and the hearth is heated. Flame spouts when, through the utility model discloses people observes and studies repeatedly, combine a lot of repetition test, can produce a large amount of waste gases after the flame burning that spouts forward and circle round to outer pipe 1 and go out fire end periphery, partly waste gas is arranged to smoke window 62, start waste gas updraft ventilator 32, the waste gas that accumulates in outer pipe 1 play fire end periphery gets into waste gas resorption pipe cover 31, then through heat exchanger 34, reentrant waste gas reflux pipe 33, discharge into to combustion space section 101 in, with the gas in the combustion space section 101, the combustion-supporting gas mixed combustion, because the oxygen content is few in the waste gas, thereby can dilute the density of oxygen in the combustion-supporting gas, reduce the combustion temperature in the combustion space section 101, control nitrogen oxide's formation volume effectively, reach the control requirement of environmental protection.

By adopting the low-nitrogen condensation preventing burner, a large amount of exhaust gas can be circularly introduced into the combustion space section 101 to be mixed with the combustion-supporting gas and the fuel gas, the combustion temperature is maintained below the temperature at which a large amount of nitrogen oxides are generated for a long time, and when the combustion temperature rises and the amount of generated nitrogen oxides is large, the concentration of nitrogen oxides in the exhaust gas is high, and the amount of nitrogen oxides circularly introduced into the combustion space section is also large, thereby lowering the combustion temperature.

Compared with the traditional combustion device, the low-nitrogen condensation-preventing combustor has the advantages that the waste gas suck-back structure 3 is arranged at the fire outlet end, can fully absorb and recycle the convoluted waste gas, meet the requirement of reducing the combustion temperature, meet the control on the generation amount of nitrogen oxides, fully break through the traditional thought that the waste gas is concentrated and collected at the smoke outlet and cannot return to the vicinity of the fire outlet end, because the smoke exhaust port is far away from the fire outlet end, otherwise the smoke exhaust port can directly exhaust the combustion heat, the application learns that the combustion waste gas part can be convoluted to the vicinity of the fire outlet end (namely the periphery of the outer tube), so, design the aforesaid and set up waste gas resorption structure 3 in the end periphery of going out a fire, the waste gas in the resorption furnace can reach the formation volume that restraines nitrogen oxide equally, and satisfies the required temperature effect of furnace. Compare in prior art, can avoid using completely in the tradition to be used for leading-in waste gas to the combustor to follow the return pipe with the flue gas to avoided waste gas to follow the return pipe because the problem of condensation damage, and applied this application low-nitrogen combustion system simple structure of low-nitrogen anti-condensation combustor, need not to arrange external waste gas in and follow the return pipe, overall structure is simple, compact, and occupation space is little, is convenient for arrange, has reduced the holistic manufacturing degree of difficulty of boiler and cost.

In addition, this application can preheat the combustion-supporting gas that the external world sent into through setting up the heat exchanger, sends into to preheat intraductal combustion-supporting gas and changes after preheating and light in, and simultaneously, waste gas self has reduced the temperature for it is lower relatively to get into the waste gas temperature in the combustion space section, is favorable to reducing the temperature of burning. Compare in the tradition, the waste gas of traditional low-nitrogen anti-condensation combustor directly gets into out the fire end burning and then discharges into furnace, and most is discharged from the smoke window again, and the heat of the waste gas of failing to make full use of, the low-nitrogen anti-condensation combustor make full use of the heat of waste gas, and is more energy-conserving to, the journey that the waste gas of this application passed through can fully shorten, need not to follow the long distance route of stove tail to furnace end, can avoid the thermal loss of waste gas.

It can be understood that in the application, the combustion-supporting gas is not limited to air, but also can be other combustion-supporting media, and the fuel gas is not limited to natural gas, but can be other fuel media, even fuel oil and the like.

It can be understood that the combustion system comprises a control box 8, and the control box 8 is arranged outside the boiler and used for starting and adjusting the rotation speed of the combustion-supporting gas conveying device and the fuel gas conveying device, so that the conveying amount of the combustion-supporting gas and the fuel gas is controlled.

The utility model discloses combustion system's combustion method, including following step:

the combustion-supporting gas conveying device 35, the gas conveying device and the waste gas exhaust device 32 are started, gas is filled into the inner tube barrel 2 through the gas interface 21, combustion-supporting gas is filled into the outer tube barrel 1 through the combustion-supporting gas interface, the gas and the combustion-supporting gas are premixed, premixed gas is ignited, flame generated by combustion is sprayed into a furnace 6 hearth from a fire outlet end, waste gas backflow which is opposite to the flame spraying direction and is formed after the flame is combusted is formed in the hearth, the waste gas backflow is sucked into the waste gas suck-back tube cover 31 through the waste gas exhaust device 32 and is conveyed to the waste gas backflow pipe 33 and flows back into the combustion space section 101 of the fire outlet end of the outer tube barrel 1.

When the heat exchanger 34 is installed, the combustion-supporting gas conveying device 35 conveys combustion-supporting gas to enter the outer tube 1 after passing through the heat exchanger 34, waste gas enters the waste gas return pipe 33 after passing through the waste gas return suction pipe cover 31, and heat exchange between the combustion-supporting gas and the waste gas is realized.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all utilize the equivalent structure or equivalent flow transformation that the content of the specification does, or directly or indirectly use in other related technical fields, all including in the same way the patent protection scope of the present invention.

Claims (9)

1. A low-nitrogen condensation-proof burner comprises an outer tube (1) and an inner tube (2), wherein one end of the outer tube (1) is a fire outlet end, the other end of the outer tube is a gas inlet end, the gas inlet end is provided with a combustion-supporting gas interface (11), the inner tube (2) penetrates into the outer tube (1), the inner tube (2) is provided with a gas interface (21) for mixing combustion-supporting gas led in by the outer tube (1) and gas led in by the inner tube (2) in the fire outlet end of the outer tube (1) and then igniting the mixture, and is characterized by comprising a waste gas resorption structure (3), the waste gas resorption structure (3) comprises a waste gas resorption tube cover (31) and a waste gas extraction device (32), the waste gas resorption tube cover (31) is arranged on the outer wall of the fire outlet end of the outer tube (1) and is provided with a waste gas resorption hole (311), the waste gas extraction device (32) is connected with the waste gas resorption tube cover (31) and the waste gas extraction device (, the waste gas which is convoluted to the rear part of the fire outlet end after being combusted is sucked into the waste gas return pipe cover (31) and then is conveyed into the fire outlet end of the outer pipe barrel (1), the conveyed back waste gas is mixed with combustion-supporting gas guided by the outer pipe barrel (1) and fuel gas guided by the inner pipe barrel (2), the waste gas is combusted in the fire outlet end, and a cooling device (9) is sleeved on the periphery of the waste gas return pipe cover (31) to reduce the temperature of the waste gas return pipe cover (31).

2. The low-nitrogen condensation-preventing burner as claimed in claim 1, wherein the cooling means (9) comprises a water reservoir (91) and an inlet pipe (92) and an outlet pipe (93) respectively communicating with the water reservoir (91), and heat exchange occurs between the cold water and the exhaust gas return pipe cover (31) by injecting cold water from the inlet pipe (92) into the water reservoir (91), thereby reducing the temperature of the exhaust gas return pipe cover (31).

3. The low-nitrogen condensation-preventing burner as claimed in claim 2, wherein the water reservoir (91) is of a cylindrical structure in which an annular water storage chamber (94) is formed.

4. The low-nitrogen condensation-preventing burner as claimed in claim 2, wherein the water inlet pipe (92) and the water outlet pipe (93) are oppositely disposed on the water reservoir (91).

5. The low-nitrogen condensation-preventing burner according to claim 1, wherein the flue gas recirculation structure (3) comprises a flue gas recirculation pipe (33), the flue gas recirculation pipe (33) penetrates into the inner tube (2), and the flue gas draft device (32) is connected to the flue gas recirculation tube cover (31) at one end and the flue gas recirculation pipe (33) at the other end through a pipeline.

6. The low-nitrogen condensation-preventing burner according to claim 5, wherein the flame-out end has a combustion space section (101), the inner tube (2) has a gas-outlet end, a premix tube (4) is connected to the outer peripheral wall of the gas-outlet end, and the other end of the premix tube (4) extends to the combustion space section (101).

7. The low-nitrogen condensation-preventing burner according to claim 6, characterized in that the outlet end of the inner tube (2) extends to a position adjacent to the premix tube (4) and the flue gas return pipe (33) extends to a position adjacent to the combustion space section (101).

8. The low-nitrogen condensation-preventing burner according to claim 5, wherein the exhaust gas recirculation structure (3) further comprises a heat exchanger (34), the heat exchanger (34) is provided with a first air inlet and a first air outlet, a second air inlet and a second air outlet, the first air inlet is connected with the air outlet (30) of the exhaust gas recirculation pipe cover (31), the first air outlet is connected with the exhaust gas draft device (32), an oxidant-supporting gas conveying device (35) is connected to the second air inlet, and the second air outlet is connected to the oxidant-supporting gas inlet (11).

9. The utility model provides a combustion system, includes furnace body (6) and installs the combustor on furnace body (6), and furnace body (6) have furnace, have seted up burner hole (61) on the front side oven of furnace body, and the top of furnace body is close to the rear side oven wall and is provided with smoke window (62) to supply the exhaust combustion exhaust gas in the furnace, its characterized in that: the burner adopts the low-nitrogen condensation-preventing burner as claimed in any one of claims 1 to 8, which is arranged on the front side wall of the furnace body (6), and the port of the fire outlet end of the outer tube (1) extends into the hearth.

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