Low NOx gas burner and gas collocation method thereof
Technical field
The present invention relates to combustion with reduced pollutants technical field, particularly relate to and a kind ofly reduce flame temperature and the gas burner of flue gas and gas collocation method thereof in burner injection combustion chamber.
Background technology
In recent years, haze has become grave danger of publilc health, and nitrogen oxide is the main composition of haze, and the discharge controlling nitrogen oxide has become the Important Action administering haze weather.Along with Energy restructuring, natural gas energy resource proportion significantly increases, the situation that fuel gas buring discharge nitrogen oxide pollutes more and more receives publicity, country promulgates " boiler Air Pollutant Emission " new standard, strict index has been formulated to discharged nitrous oxides, stricter index will be formulated in some key areas, if Beijing is 80mg/m to gas fired-boiler emission limits of nitrogen oxides
3(benchmark oxygen content 3.5%).
Fuel gas buring produces NOx and belongs to heating power type, produce NOx number depend on flame temperature, flame temperature is relevant with furnace heat release, for the gas fired-boiler that furnace heat release is larger, as thermal power is less than the gas fired-boiler of 14MW, combustion space is relatively little, and heat exchange area is few, is unfavorable for reducing flame temperature.So, emission limits of nitrogen oxides be made lower than 80mg/m
3(benchmark oxygen content 3.5%), burner only adopts the technical measures reducing flame temperature to be not enough to the formation of degree of depth suppression nitrogen oxide, for this reason, how more effectively to suppress the formation of nitrogen oxide, also needs further research.
Summary of the invention
The object of this invention is to provide a kind of discharged nitrous oxides and meet existing relevant national standard and lower than 60mg/m
3the low NOx gas burner of (benchmark oxygen content 3.5%) and gas collocation method thereof, solve the technical problem of the poor effect that traditional gas burner suppresses nitrogen oxide to be formed.
For achieving the above object, the present invention adopts following technical scheme: a kind of low NOx gas burner, includes the inner core and urceolus that coaxially arrange and the outer ring gas spray head communicated with gas pipeline be arranged between inner core with urceolus, it is characterized in that:
The center of described inner core is provided with the central tube of conveying air and combustion gas mixing gas.
On described central tube, cover has inner ring combustion gas sleeve, and inner ring combustion gas sleeve be surrounded by the inner ring blast tube communicated with gas pipeline between central tube, the upper end surrounding sidewall of inner ring combustion gas sleeve also has the inner ring gas jet orifice of the radial direction communicated with inner ring blast tube.
Space inside described inner core is inner ring combustion zone, and the space between described urceolus and inner core, above the gas spray head of outer ring is combustion zone, outer ring.
Preferably, on the inner ring combustion gas sleeve below described inner ring gas jet orifice, cover has air distributor, and this air distributor comprises the air distribution plate of a circle, and described inner core is arranged on this air distribution plate, and described inner core is arranged on air distribution plate.Air distribution plate inside described inner core is evenly equipped with through hole, and described inner ring combustion zone is communicated with the space below air distribution plate by through hole.Leave circumferential weld between described air distribution plate and urceolus, combustion zone, described outer ring is communicated with the space below air distribution plate by circumferential weld.
Preferably, it be the swirl vane of an angle with air distribution plate that the top of described through hole is provided with what guide air flow, and described inner ring combustion zone is stitched by the eddy flow formed by through hole and swirl vane and communicated with the space below air distribution plate.The angle of described swirl vane and air distribution plate is 30 ° ~ 45 °.
Preferably, described urceolus is circumferentially provided with at least one circle perforation extracting flue gas in combustion chamber, the inner side of perforation is provided with again the injection sheet tilted to urceolus axle center from bottom to top guiding flue gas flow direction.The angle of described injection sheet and urceolus is 30 ° ~ 60 °.
Preferably, described outer ring gas spray head is higher than inner ring gas jet orifice, between urceolus and inner core, the below of outer ring gas spray head is provided with outer ring combustion air passage, and combustion zone, described outer ring is communicated with the space below air distribution plate by outer ring combustion air passage and circumferential weld.
Preferably, the top of described urceolus is higher than outer ring gas spray head, and outer ring gas spray head is higher than the top of inner core, and the top of inner core is higher than inner ring gas jet orifice.
A kind of gas collocation method of low NOx gas burner, it is characterized in that: the gas flow in described inner ring combustion zone accounts for 25% ~ 30% of total gas flow, air mass flow in described inner ring combustion zone accounts for 10% ~ 20% of total air mass flow, gas flow in combustion zone, described outer ring accounts for 70% ~ 75% of total gas flow, and the air mass flow in combustion zone, described outer ring accounts for 80% ~ 90% of total air mass flow.
The gas flow of described central tube ejection can account for 5% ~ 10% of the gas flow in inner ring combustion zone; The air mass flow of described central tube ejection can account for 15% ~ 20% of the air mass flow in inner ring combustion zone.
Compared with prior art the present invention has following characteristics and beneficial effect: the invention provides a kind of emission limits of nitrogen oxides lower than 60mg/m
3the gas burner of (benchmark oxygen content 3.5%), can make flame temperature reduce and the oxygen reduced in combustion air is combined with nitrogen and nitrogen-containing group, thus effectively inhibits the generation of NOx, reduces the discharge of NOx.
In the present invention, central tube conveying air and combustion gas mixing gas (Some gases and air pre-mixing gas) enter inner ring combustion zone, and combustion gas and air pre-mixing enhance burning, can ensure the not de-fire of flame.
In the present invention, the inner space of inner core forms inner ring combustion zone, and inner ring combustion air forms swirling eddy after being stitched by eddy flow, and the multiply combustion gas thread that swirling eddy sprays with inner ring gas jet orifice radial direction mixes, enhance air and combustion gas mixing, shorten the time of staying of flue gas in high-temperature region.
In the present invention, the gas-flow that outer ring combustion air is axially sprayed by outer ring combustion air passage and multiple outer rings gas spray head mixes, and combustion zone, outer ring is made up of multiple flame, adds flame area of dissipation, is conducive to reducing flame temperature.
The present invention is also provided with perforation and injection sheet on urceolus, and when the mist of air and combustion gas sprays from urceolus, form negative pressuren zone at perforation place, in combustion chamber, flue gas is along injection sheet, is inhaled into combustion zone by entering perforation.
The present invention is also provided with air distributor, this air distributor is compared with traditional cyclone, not only structure simple, be easy to processing, and both there is the function of cyclone, air swirl can be made, there is again the function of air distribution, air can be distributed according to need accurately and to go to the inner ring combustion zone and combustion zone, outer ring of combustion gas gas apparatus, formed two kinds of various flows to air-flow, solve in existing gas burner and there is no air distributor, accurately air can not be sent into the problem of each combustion zone.Air is sent into each combustion zone by air distributor by the present invention accurately, can reduce the discharge capacity of the nitrogen oxide of gas burner further.
In the present invention, gas flow in inner ring combustion zone accounts for 25% ~ 30% of total gas flow, air mass flow in inner ring combustion zone accounts for 10% of total air mass flow, gas flow in combustion zone, outer ring accounts for 70% ~ 75% of total gas flow, and the air mass flow in combustion zone, outer ring accounts for 80% ~ 90% of total air mass flow.Inner ring combustion zone excess air coefficient is less than 1.0, and be dense burning, combustion zone, outer ring excess air coefficient is greater than 1.2, is light burning, and the multiple flame of combination and combustion zone, outer ring of inside and outside circle bias combustion, reduces flame temperature.
The present invention adopts inside and outside circle to burn, and the dense burning of inner ring, the light burning in outer ring, simultaneously also on the basis of which, utilize perforation and injection sheet that flue gas in combustion chamber is introduced combustion zone, the concentration of combustion zone oxygen is reduced, and the oxygen reduced in combustion air is combined with nitrogen and nitrogen-containing group, thus effectively inhibits the generation of NOx, and then reaching the NOx only producing minute quantity, discharged nitrous oxides is lower than 60mg/m
3the effect of (benchmark oxygen content 3.5%).
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the present invention will be further described in detail.
Fig. 1 is structural representation of the present invention.
Fig. 2 is schematic top plan view of the present invention.
Fig. 3 is the schematic diagram of A-A section in Fig. 2.
Fig. 4 is the structural representation of urceolus.
Reference numeral: 1-central tube, 2-inner ring gas jet orifice, 3-air distribution plate, 4-swirl vane, 5-inner core, 6-outer ring gas spray head, 7-urceolus, 8-injection sheet, 9-inner ring combustion zone, 10-outer ring combustion air passage, 11-circumferential weld, 12-through hole, 13-perforation, 14-breach, combustion zone, 15-outer ring, 16-inner ring combustion gas sleeve, 17-inner ring blast tube.
Detailed description of the invention
Embodiment is see shown in Fig. 1-4, this low NOx gas burner, include the inner core 5 and urceolus 7 that coaxially arrange and the outer ring gas spray head 6 communicated with gas pipeline be arranged between inner core 5 with urceolus 7, the shower nozzle top of outer ring gas spray head 6 is equipped with 1 gas jet orifice.
The center of described inner core 5 is provided with the central tube 1 of conveying air and combustion gas mixing gas.
On described central tube 1, cover has inner ring combustion gas sleeve 16, and inner ring combustion gas sleeve 16 be surrounded by the inner ring blast tube 17 communicated with gas pipeline between central tube 1, the upper end surrounding sidewall of inner ring combustion gas sleeve 16 also has the inner ring gas jet orifice 2 of the radial direction communicated with inner ring blast tube 17.
On inner ring combustion gas sleeve 16 below described inner ring gas jet orifice 2, cover has air distributor again, this air distributor comprises the air distribution plate 3 of the circle that is made up of heat-resisting steel sheet and plate, described inner core 5 is arranged on air distribution plate 3, and inner core 5, air distribution plate 3 are surrounded by inner ring circle combustion zone 9 with inner ring combustion gas sleeve 16.On described air distribution plate 3, the position of corresponding outer ring gas spray head 6 is provided with breach 14, makes air distribution plate be that lace is discoid.
Air distribution plate 3 inside described inner core 5 is evenly equipped with the through hole 12 of strip, the top of through hole 12 be provided with again guide air flow with the swirl vane 4 of air distribution plate 3 in 30 ° ~ 45 ° of angles, described inner ring combustion zone 9 is communicated with the space below air distribution plate by the eddy flow seam formed by through hole 12 and swirl vane 4.The combustion air of the eddy flow needed for described inner ring combustion zone 9 is that the eddy flow seam that the air below air distribution plate passes through to be formed by through hole 12 and swirl vane 4 enters inner ring combustion zone 9.
Space inside described urceolus 7, above outer ring gas spray head 6 is combustion zone, outer ring 15, circumferential weld 11 is left between described air distribution plate 3 and urceolus 7, in the present embodiment, outer ring gas spray head 6 is higher than inner ring gas jet orifice 2, between urceolus 7 and inner core 5, the below of outer ring gas spray head 6 is provided with outer ring combustion air path 10, and combustion zone, described outer ring 15 is communicated with the space below air distribution plate by outer ring combustion air path 10 and circumferential weld 11.Combustion air needed for combustion zone, described outer ring 15 is that the air below air distribution plate enters combustion zone, outer ring 15 by circumferential weld 11.
In the present embodiment, described urceolus 7 is circumferentially provided with at least one circle perforation 13 extracting flue gas in combustion chamber, the inner side of perforation 13 is provided with again the injection sheet 8 tilted to urceolus axle center from bottom to top guiding flue gas flow direction, and described injection sheet 8 is generally 30 ° ~ 60 ° with the angle of urceolus 7.In addition, in other embodiments, Liang Quan, three circles or more circle perforation can also be designed on urceolus.
See Fig. 4, in the present embodiment, perforation 13 is arch hole.In other embodiments, also semicircle orifice or square hole etc. can be designed to.
In the present embodiment, the top of urceolus 7 is higher than outer ring gas spray head 6, and outer ring gas spray head 6 is higher than the top of inner core 5, and the top of inner core 5 is higher than inner ring gas jet orifice 2.
Applicant is found by research, and described low NOx gas burner adopts following combustion gas configuration mode, and result of use is best, and the discharged nitrous oxides of gas burner can be made lower than 60mg/m
3(benchmark oxygen content 3.5%): the gas flow in described inner ring combustion zone 9 accounts for 25% ~ 30% of total gas flow, air mass flow in described inner ring combustion zone 9 accounts for 10% ~ 20% of total air mass flow, gas flow in combustion zone, described outer ring 15 accounts for 70% ~ 75% of total gas flow, and the air mass flow in combustion zone, described outer ring 15 accounts for 80% ~ 90% of total air mass flow.
In addition, as most preferred embodiment, the gas flow that described central tube 1 sprays accounts for 5% ~ 10% of the gas flow in inner ring combustion zone, and the air mass flow that described central tube 1 sprays accounts for 15% ~ 20% of the air mass flow in inner ring combustion zone.
In Fig. 1, hollow arrow represents air and combustion gas mixing gas, and solid arrow represents combustion gas, and dotted arrow represents air.