CN212298953U - Device for reducing NOx emission through flue gas circulation - Google Patents
Device for reducing NOx emission through flue gas circulation Download PDFInfo
- Publication number
- CN212298953U CN212298953U CN202020498712.1U CN202020498712U CN212298953U CN 212298953 U CN212298953 U CN 212298953U CN 202020498712 U CN202020498712 U CN 202020498712U CN 212298953 U CN212298953 U CN 212298953U
- Authority
- CN
- China
- Prior art keywords
- pipe
- flue gas
- exhaust
- smoke
- burner
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Abstract
The utility model discloses a device that reduces NOx through flue gas circulation and discharge, the device is including the furnace bottom combustor body, exhaust connection pipe and the convection current pipe of discharging fume that connects gradually the top of the pipe of discharging fume sets up smoke exhaust fan, and the outside of the pipe of discharging fume and combustor body of convection current sets up the flue gas circulation subassembly in order to discharge fume with 10% ~ 30% in the pipe of discharging fume and send back to the combustor body. Adopt the scheme of this application, do not change to the structure basis of current pyrolysis furnace, flue gas extrinsic cycle technique can save 80% expense than denitration through the SCR reactor, and the running cost is low moreover, does not produce extra catalyst replacement cost, is convenient for reform transform and implement.
Description
Technical Field
The utility model relates to a pyrolysis furnace technique especially relates to a device that reduces NOx through gas circulation and discharges.
Background
At present, the domestic cracking furnace generally adopts a steam spray gun technology that a low NOx burner is matched with a bottom burner, the temperature of the flame center of the bottom burner is reduced by reducing the injection of steam, and then the generation of thermal NOx is inhibited, so that the standard emission of NOx of the cracking furnace under the working conditions of coke burning and heat standby is realized. According to the combustion technical scheme, the steam and gas semi-premixed low-nitrogen-oxygen combustion and gas grading low-nitrogen-oxygen combustion technologies are carefully and mutually coupled, so that the generation of NOx is further reduced, but the running cost of the scheme is increased more.
In the staged combustion, primary fuel gas is directly subjected to diffusion combustion with air, so that the combustion flame temperature reaches the theoretical combustion temperature, and meanwhile, the surrounding combustion-supporting air contains a large amount of oxygen, so that a large amount of NOx can be generated. No relevant report that the standard emission of NOx under the working conditions of burning and hot standby is realized by adopting a flue gas external circulation technology is seen in the prior art.
Some newly-built ethylene devices adopt the scheme of SCR denitration, introduce liquid ammonia and nitrogen oxide reaction, reduce final NOx's emission, but the expense of SCR catalyst is higher, the life-span of catalyst is generally about 3 years, adopt the technique of flue gas circulation can save 80% expense, and to the cracking furnace that has put into production, need increase supporting liquid ammonia storage facility, nozzle, and increase SCR catalyst bed module at existing cracking furnace convection section, also be a challenge to the basis of cracking furnace, the cost increases.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects of the prior art, the utility model aims to provide a device for reducing NOx emission through flue gas circulation, which can solve the problems.
The design principle of the device is as follows: a flue gas external circulation system is added on the basis of the existing low NOx burner, and partial flue gas passes through an induced draft fan, is mixed with combustion-supporting air and then enters the burner, so that the oxygen content of the combustion-supporting air is reduced, the partial flue gas content of flame is increased, and finally the highest temperature of the flame and the concentration of oxygen participating in NOx reaction are reduced.
The technical scheme is as follows: the purpose of the utility model is realized by adopting the following technical scheme.
The utility model provides a device that reduces NOx through flue gas circulation discharges, is including the combustor body, exhaust connecting pipe and the convection current pipe of discharging fume that connect gradually the top of the pipe of discharging fume sets up smoke exhaust fan, and the convection current is discharged fume the outside of pipe and combustor body and is set up the flue gas circulation subassembly and send 10% ~ 30% in with the convection current pipe of discharging fume back to the combustor body, and through a plurality of combustors of flue gas distribution passageway toward combustor body bottom are sent to low temperature flue gas behind the flue gas circulation subassembly, thereby directly or indirectly spout into the flame center of burning with low temperature flue gas and reduce NOx formation volume.
Preferably, the flue gas circulation subassembly is divided the pipe including the smoke return pipe, circulating fan, circulation house steward and the flue gas that connect gradually, the one end of smoke return pipe is connected to and is close to on the body of convection current exhaust pipe the exhaust fan department, the other end of smoke return pipe is connected to circulating fan's air intake, the upstream end of circulation house steward is connected to circulating fan's air outlet, the downstream section setting of circulation house steward is in the furnace lower part air feed department of combustor body, and the flue gas that many perpendicular upward openings set up is connected on the body of circulation house steward alignment combustor body air feed department and is divided the pipe.
Preferably, the pipe length L of the exhaust connecting pipe is less than or equal to the pipe diameter d of the connecting pipe; the pipe diameter d of the connecting pipe of the exhaust connecting pipe is smaller than the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe, and the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe is smaller than the maximum inner diameter d2 of the hearth of the burner body.
Preferably, the pipe diameter d of the connecting pipe of the exhaust connecting pipe is less than or equal to half of the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe.
Preferably, the relationship between the height h of the position where the upstream end of the smoke return pipe is connected to the convection smoke exhaust pipe and the pipe diameter d of the connecting pipe of the exhaust connecting pipe is as follows: h is more than or equal to 6 d.
Preferably, the burner body is a cracking furnace.
Preferably, the flue gas recirculation assembly returns 20% of the flue gas in the convection flue gas duct to the burner body.
Preferably, the exhaust connecting pipe adopts a straight pipe or a bent pipe.
Preferably, the burner body is a cracking furnace.
Preferably, the low-temperature flue gas enters the inlet air channel of the burner through the flue gas channel at the bottom of the burner body corresponding to the flue gas branch pipe, and is mixed with air and then is mixed with fuel from the fuel pipe through the middle channel of the burner block for combustion.
Preferably, the low-temperature flue gas enters the middle channel of the burner block through a flue gas channel at the bottom of the burner body corresponding to the flue gas branch pipe, and is mixed and combusted with air from the burner inlet air channel and fuel from the fuel pipe.
Preferably, the low-temperature flue gas passes through the furnace bottom refractory material through the flue gas branch pipe corresponding to the bottom of the burner body and directly enters the bottom of the hearth, and the negative pressure generated by combustion is mixed with air and fuel in the middle channel of the burner block for combustion.
Compared with the prior art, the beneficial effects of the utility model reside in that: adopt the scheme of this application, do not change to the structure basis of current pyrolysis furnace, cancel current steam spraying method, flue gas extrinsic cycle technique can save 80% expense than denitration through the SCR reactor, and the running cost is low moreover, does not produce extra catalyst replacement cost, is convenient for reform transform and implement.
Drawings
FIG. 1 is a schematic view of a straight pipe connecting pipe adopted by a device for reducing NOx emission through flue gas circulation according to the present invention;
FIG. 2 is a schematic view of an exhaust connection pipe using a bent pipe
FIG. 3 illustrates one embodiment of the low temperature flue gas entering the burner body;
FIG. 4 is a second embodiment of the low temperature flue gas entering the burner body;
fig. 5 is a third embodiment of the low temperature flue gas entering the burner body.
In the figure: 1. a burner body; 2. a convection smoke exhaust pipe; 3. an exhaust connecting pipe; 4. a smoke exhaust fan; 5. a smoke returning pipe; 6. a circulating fan; 7. a circulation main pipe; 8. flue gas is branched; 9. a burner inlet duct; 10. a burner block middle passage; 11. a fuel tube.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.
Referring to fig. 1 and 2, the device for reducing NOx emission through flue gas circulation comprises a burner body 1, an exhaust connecting pipe 3 and a convection smoke exhaust pipe 2 which are connected in sequence, wherein a smoke exhaust fan 4 is arranged at the top end of the convection smoke exhaust pipe 2, and a flue gas circulation component is arranged outside the convection smoke exhaust pipe 2 and the burner body 1 so as to send 10% -30% of smoke exhaust in the convection smoke exhaust pipe 2 back to the burner body 1.
Wherein, the burner body 1 is a cracking furnace.
Wherein the flue gas circulation assembly returns 20% of the flue gas in the convection flue gas duct 2 to the burner body 1.
Wherein, the exhaust connecting pipe 3 adopts a straight pipe or a bent pipe.
Flue gas circulation assembly
The flue gas circulation subassembly is including the smoke return pipe 5, circulating fan 6, circulation house steward 7 and the flue gas branch pipe 8 that connect gradually, the one end of smoke return pipe 5 is connected to and is close to on the body of convection current exhaust pipe 2 the exhaust fan 4 department, the other end of smoke return pipe 5 is connected to circulating fan 6's air intake, circulation house steward 7's upstream end is connected to circulating fan 6's air outlet, circulation house steward 7's downstream section sets up the furnace lower part air feed department of combustor body 1, and circulation house steward 7 aims at the flue gas branch pipe 8 that connects many perpendicular openings that make progress setting on the body of combustor body 1 air feed department. The flue gas branch pipe 8 is with the circulating flue gas from the burner tip lateral wall of furnace bottom position get into combustor body 1, the furnace of pyrolysis furnace promptly.
Relationship of pipe bodies
The pipe length L of the exhaust connecting pipe 3 is less than or equal to the pipe diameter d of the connecting pipe; the pipe diameter d of the connecting pipe of the exhaust connecting pipe 3 is smaller than the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe 2, and the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe 2 is smaller than the maximum inner diameter d2 of the hearth of the burner body 1.
Furthermore, the pipe diameter d of the connecting pipe of the exhaust connecting pipe 3 is less than or equal to half of the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe 2.
Further, the relationship between the height h of the position where the upstream end of the smoke return pipe 5 is connected to the convection smoke exhaust pipe 2 and the pipe diameter d of the connecting pipe of the exhaust connecting pipe 3 is as follows: h is more than or equal to 6 d.
The low temperature flue gas enters the burner body 1 in various ways, see the three ways of fig. 3-5.
Referring to fig. 3, low-temperature flue gas enters a combustor inlet air duct 9 through a flue gas channel at the bottom of the combustor body 1 corresponding to the flue gas branch pipe 8, and is mixed with air and then is mixed with fuel from a fuel pipe 11 through a burner block middle channel 10 for combustion.
Referring to fig. 4, low-temperature flue gas enters a burner block middle channel 10 through a flue gas channel at the bottom of the burner body 1 corresponding to the flue gas branch pipe 8, and is mixed and combusted with air from a burner inlet air channel 9 and fuel from a fuel pipe 11.
Referring to fig. 5, low-temperature flue gas passes through the bottom of the burner body 1 through the flue gas branch pipe 8 and the furnace bottom refractory material to directly enter the bottom of the hearth, and is mixed with air and fuel in the burner block middle channel 10 for combustion through negative pressure generated by combustion.
With the above apparatus, the present application provides a method for reducing NOx emission levels in ethylene cracking furnaces by flue gas recirculation, the method comprising.
a) The low-temperature flue gas is controllably led out from the smoke exhaust end of the cracking furnace.
b) Low-temperature flue gas is introduced to air supply channels of burners at the bottom of the furnace through a compression device or introduced to the bottom of the cracking furnace through a special flue gas channel and then enters the lower part of the hearth.
c) The low-temperature flue gas of the cracking furnace is returned to the combustion area of the burner at the bottom of the cracking furnace through the air supply duct or the flue gas channel, so that the central temperature of the combustion area is reduced, the generation amount of NOx is reduced, and the NOx emission level of the cracking furnace is reduced.
Further, the circulating low-temperature flue gas is introduced to all or part of the burners at the bottom of the burner body 1, wherein the temperature range of the low-temperature flue gas is 80-160 ℃, and the low-temperature flue gas directly or indirectly enters the flame center to reduce the combustion temperature so as to reduce the generation amount of NOx.
In summary, holes are formed in the proper positions of an induced draft fan outlet chimney of a cracking furnace, namely the combustor body 1, a part of flue gas is led out through a newly-added flue, the part of flue gas is sent to a collection air channel at the bottom of the cracking furnace through a compressor and is respectively distributed to each combustor at the bottom of the furnace, and circulating flue gas is sprayed into a combustion area of the combustor through each flue gas spray gun extending into the characteristic position inside a burner block of the combustor, so that the central temperature of flame in the combustion area is reduced, the nitrogen oxide generated by combustion is reduced, and the aim of reducing the NOx emission level of the cracking furnace is fulfilled. Through verification, the cost can be saved by 80% by adopting the flue gas circulation technology compared with the denitration through an SCR reactor, and matched liquid ammonia storage facilities, nozzles and an SCR catalyst bed layer module are not required to be added. The on-site implementation is easy, and the whole structure of the cracking furnace is not influenced.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.
Claims (8)
1. The utility model provides a device that NOx discharged is reduced through flue gas circulation, includes combustor body (1), exhaust connecting pipe (3) and convection current that connect gradually and discharges fume tub (2), its characterized in that: the top of convection current pipe (2) of discharging fume sets up smoke exhaust fan (4), and the outside of convection current pipe (2) of discharging fume and combustor body (1) sets up flue gas circulation subassembly in order to discharge fume with 10% ~ 30% in the convection current pipe of discharging fume and send back to combustor body (1), and through flue gas circulation subassembly back low temperature flue gas send to a plurality of combustors of combustor body (1) bottom through flue gas distribution channel, thereby directly or indirectly spout the low temperature flue gas into the flame center of burning thereby reduce NOx formation volume.
2. The apparatus of claim 1, wherein: the flue gas circulation subassembly is including the smoke return pipe (5), circulating fan (6), circulation house steward (7) and the flue gas branch pipe (8) that connect gradually, the one end of smoke return pipe (5) is connected to and is close to on the body of convection current exhaust pipe (2) exhaust fume fan (4) department, the other end of smoke return pipe (5) is connected to the air intake of circulating fan (6), the upstream end of circulation house steward (7) is connected to the air outlet of circulating fan (6), the downstream section setting of circulation house steward (7) is in the furnace lower part air feed department of combustor body (1), and circulation house steward (7) aim at and connect many perpendicular flue gas branch pipes (8) that upwards open the setting on the body of combustor body (1) air feed department.
3. The apparatus of claim 1 or 2, wherein: the pipe length L of the exhaust connecting pipe (3) is less than or equal to the pipe diameter d of the connecting pipe; the pipe diameter d of the connecting pipe of the exhaust connecting pipe (3) is smaller than the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe (2), and the pipe diameter d1 of the smoke pipe of the convection smoke exhaust pipe (2) is smaller than the maximum inner diameter d2 of the hearth of the combustor body (1).
4. The apparatus of claim 2, wherein: the burner body (1) is a cracking furnace.
5. The apparatus of claim 4, wherein: the exhaust connecting pipe (3) adopts a straight pipe or a bent pipe.
6. The apparatus of claim 5, wherein: the low-temperature flue gas enters a combustor inlet air channel (9) through a flue gas channel at the bottom of the combustor body (1) corresponding to the flue gas branch pipe (8), and is mixed with air and then combusted with fuel from a fuel pipe (11) through a burner block middle channel (10).
7. The apparatus of claim 5, wherein: the low-temperature flue gas enters a burner block middle channel (10) through a flue gas channel at the bottom of the burner body (1) corresponding to the flue gas branch pipe (8), and is mixed with air from a burner inlet air channel (9) and fuel from a fuel pipe (11) for combustion.
8. The apparatus of claim 5, wherein: the low-temperature flue gas passes through the bottom of the burner body (1) through the flue gas branch pipe (8) and penetrates through the furnace bottom refractory material to directly enter the bottom of the hearth, and the negative pressure generated by combustion is mixed with air and fuel in the burner block middle channel (10) for combustion.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020498712.1U CN212298953U (en) | 2020-04-08 | 2020-04-08 | Device for reducing NOx emission through flue gas circulation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020498712.1U CN212298953U (en) | 2020-04-08 | 2020-04-08 | Device for reducing NOx emission through flue gas circulation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN212298953U true CN212298953U (en) | 2021-01-05 |
Family
ID=73963039
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020498712.1U Active CN212298953U (en) | 2020-04-08 | 2020-04-08 | Device for reducing NOx emission through flue gas circulation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN212298953U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114251655A (en) * | 2021-11-23 | 2022-03-29 | 上海工程技术大学 | Low-nitrogen combustor for segmented circulating gas |
| WO2023129941A1 (en) * | 2021-12-31 | 2023-07-06 | Honeywell International Inc. | Low nox gas burner with cooled flue gas recycle |
-
2020
- 2020-04-08 CN CN202020498712.1U patent/CN212298953U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114251655A (en) * | 2021-11-23 | 2022-03-29 | 上海工程技术大学 | Low-nitrogen combustor for segmented circulating gas |
| WO2023129941A1 (en) * | 2021-12-31 | 2023-07-06 | Honeywell International Inc. | Low nox gas burner with cooled flue gas recycle |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN202012913U (en) | Novel flue gas self-reflux low-oxygen combustor | |
| CN110107898B (en) | Coke oven gas low-nitrogen burner | |
| CN212298953U (en) | Device for reducing NOx emission through flue gas circulation | |
| CN112555828A (en) | Hearth and combustor cooling type surface cold flame premixing gas boiler | |
| CN202734221U (en) | Vertical energy-saving environmental-protection boiler | |
| CN201964415U (en) | Multinozzle semi-premixed gas burner | |
| CN207527571U (en) | A kind of natural gas boiler low nitrogen burning system | |
| CN113494707A (en) | Device and method for reducing NOx emission through flue gas circulation | |
| CN110469847B (en) | Water-cooled fuel gas ultralow nitrogen combustion device | |
| CN210153806U (en) | Coke oven gas low-nitrogen burner | |
| WO2020140381A1 (en) | Multi-ejector tube type fire plate | |
| CN107461742B (en) | Graded flameless low-nitrogen combustion head | |
| CN209977990U (en) | Low-nitrogen full-premixing steam boiler | |
| CN215259784U (en) | Combustion system for reducing emission of nitrogen oxides by utilizing flue gas external circulation | |
| CN109737402B (en) | U-shaped flame low-nitrogen oxide burner for high-temperature hearth | |
| CN107883374A (en) | A kind of natural gas boiler low nitrogen burning system and technique | |
| CN201964395U (en) | Multi-burner heating furnace | |
| CN213089813U (en) | Flue gas inner loop type low nitrogen structure | |
| CN210373419U (en) | Ultralow nitrogen emission electromechanical integration gas vacuum boiler | |
| CN216667732U (en) | Distributed multi-profile flue gas injection grading low-nitrogen combustion equipment | |
| CN210004586U (en) | ultra-low nitrogen hot-blast stove | |
| CN209853984U (en) | Combustion type glass tempering heating device | |
| CN206669729U (en) | A kind of gas instantaneous water heater burner of fractional combustion | |
| CN102032570A (en) | Top-fired high-temperature preheated-air flat-flame burner of hydrogen generation reforming furnace | |
| CN207455593U (en) | Suitable for the energy-saving low-NOx combustor of biomass marsh gas |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR01 | Patent grant | ||
| GR01 | Patent grant |