CN112923391A - Air preheater capable of reducing NOx emission of tail gas of heating furnace and using method - Google Patents
Air preheater capable of reducing NOx emission of tail gas of heating furnace and using method Download PDFInfo
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- CN112923391A CN112923391A CN202110211436.5A CN202110211436A CN112923391A CN 112923391 A CN112923391 A CN 112923391A CN 202110211436 A CN202110211436 A CN 202110211436A CN 112923391 A CN112923391 A CN 112923391A
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- air
- collecting pipe
- gas
- hot air
- outlet
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
- F23L15/00—Heating of air supplied for combustion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/004—Systems for reclaiming waste heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F27—FURNACES; KILNS; OVENS; RETORTS
- F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
- F27D17/00—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases
- F27D17/008—Arrangements for using waste heat; Arrangements for using, or disposing of, waste gases cleaning gases
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
Abstract
The invention provides a method for reducing NO in tail gas of a heating furnaceXThe invention relates to an exhausted air preheater and a using method thereof, which comprises an inlet air box, a cold air collecting pipe, a lower air box, a hot air collecting pipe and an outlet air box, wherein the inlet air box is connected with the inlet end of the cold air collecting pipe, the outlet end of the cold air collecting pipe is connected with the inlet end of the hot air collecting pipe through the lower air box, the outlet end of the hot air collecting pipe is connected with the outlet air box, a smoke introducing device is also arranged between the outlet end of the hot air collecting pipe and the outlet air box and comprises a hot air nozzle, a check valve and an ejector, the hot air nozzle is arranged at the outlet end of the hot air collecting pipe and is arranged in the ejector, the inlet of the ejector is provided with the check valve, and the outlet of the ejector is connected with the outlet.
Description
Technical Field
The invention belongs to metallurgical thermal technologyThe technical field especially relates to a can reduce heating furnace tail gas NOXVented air preheater and method of use.
Background
The air preheater is usually installed in a furnace tail flue of a heating furnace, recovers the high-temperature flue gas waste heat at the furnace tail, preheats combustion-supporting air involved in combustion, and effectively brings the high-temperature flue gas waste heat back into the furnace, so that the fuel consumption is saved, and the energy utilization efficiency is improved. The higher the air preheating temperature is, the higher the energy-saving efficiency of the furnace kiln is.
The existing air heat exchanger mainly focuses on the aspects of improving the heat exchange efficiency of equipment, reducing equipment faults, prolonging the service life of the equipment, reducing the manufacturing cost of the equipment and the like, and the existing air heat exchanger has no exception of solving various problems in production by surrounding the purpose of recovering flue gas waste heat so as to improve the service performance of the equipment.
With the improvement of the requirement of environmental protection, the treatment of pollutants in the flue gas is an important aspect of the development of the furnace kiln technology besides the implementation of waste heat recovery energy-saving measures on the flue gas of the furnace kiln at present. The national work scheme of ultralow emission modification (draft solicitation) of iron and steel enterprises from 2018 establishes stricter requirements on emission standards of atmospheric pollutants in the iron and steel industry. The NOx emission of the tail gas of the heating furnace is reduced to 150mg/m3 on the basis of the original national standard of 300mg/m3, and all large heating furnaces used at present can not meet the requirements of the new standard. The general control of NOx emissions from the combustion of fuel furnaces starts mainly from two approaches: (1) the original generation amount of NOx in the combustion process is reduced through the control of the combustion process; (2) the existing NOx in the flue gas is removed through flue gas denitration treatment. Flue gas denitration technologies, such as SNCR and SCR, require a denitration device to be installed on a flue, and also require a continuous input of a reducing agent, so that a large amount of denitration cost needs to be input. The preheater is used as a necessary energy-saving device for recovering the waste heat of the flue gas of the heating furnace, and can integrate energy conservation and emission reduction by synchronously developing the function of reducing the emission of NOx in the flue gas of the preheater, thereby becoming a brand new preheater technology which conforms to the development of furnaces and meets the requirement of environmental protection, and having wide application prospect.
Disclosure of Invention
The inventionAiming at solving the problems, the technical problem is to provide a method for reducing NO in tail gas of a heating furnaceXThe discharged air preheater and the use method thereof enable the preheater to have the function of reducing the discharge of smoke pollutants on the basis of having the conventional waste heat utilization function, thereby realizing the dual purposes of energy conservation and emission reduction.
The technical scheme adopted by the invention for solving the technical problems is as follows: can reduce heating furnace tail gas NOXThe discharged air preheater comprises an inlet air box, a cold air collecting pipe, a lower air box, a hot air collecting pipe and an outlet air box, wherein the inlet air box is connected with the inlet end of the cold air collecting pipe, the outlet end of the cold air collecting pipe is connected with the inlet end of the hot air collecting pipe through the lower air box, and the outlet end of the hot air collecting pipe is connected with the outlet air box.
According to the scheme, the end head of the inlet of the ejector is also provided with the gas collecting head, the large head end of the gas collecting head faces outwards, and the small head end of the gas collecting head is connected with the inlet of the ejector.
According to the scheme, the hot air collecting pipe is formed by arranging a plurality of rows of hot air pipes, and the hot air nozzles are arranged at the outlet ends of one or more or all of the hot air pipes.
According to the scheme, the check valve is a butterfly check valve.
According to the scheme, the gas collecting head is of a conical expansion conduit structure.
Can reduce heating furnace tail gas NOXA method of using a vented air preheater, comprising:
the air preheater is arranged in a tail flue of a heating furnace, cold air is fed by a blower, enters from an inlet air box, is preheated by high-temperature flue gas after passing through a cold air collecting pipe, a lower air box and a hot air collecting pipe, is sprayed out from a hot air nozzle, sucks the surrounding high-temperature flue gas by an ejector to form air-flue gas mixture, and finally is sent out from an outlet air box.
The invention has the beneficial effects that: provides a method for reducing NO in tail gas of a heating furnaceXThe discharged air preheater and the use method have the advantages of higher air preheating temperature, better energy-saving effect, simple equipment structure and NO new operating cost, and can effectively reduce NO of the heating furnaceXAnd the emission is realized, the heat exchange strength of the hearth of the heating furnace is improved, and the good effects of energy conservation and emission reduction are achieved.
Drawings
Fig. 1 is a schematic structural diagram of an embodiment of the present invention.
Detailed Description
For a better understanding of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings and examples.
As shown in FIG. 1, a method for reducing the NO of the tail gas of a heating furnaceXThe discharged air preheater comprises an inlet air box 1, a cold air collecting pipe 2, a lower air box 3, a hot air collecting pipe 4 and an outlet air box 5, wherein the inlet air box is connected with the inlet end of the cold air collecting pipe, the outlet end of the cold air collecting pipe is connected with the inlet end of the hot air collecting pipe through the lower air box, the outlet end of the hot air collecting pipe is connected with the outlet air box, a smoke introducing device is further arranged between the outlet end of the hot air collecting pipe and the outlet air box and comprises a hot air nozzle 6, a check valve 7 and an ejector 8, the hot air nozzle is arranged at the outlet end of the hot air collecting pipe and is arranged in the ejector, the check valve is arranged at the inlet of.
The end head of the inlet of the ejector is also provided with a gas collecting head 9 which is a conical expansion duct structure, the large end of the gas collecting head faces outwards, and the small end is connected with the inlet of the ejector.
The high-temperature air preheated by the air preheater sucks a large amount of high-temperature flue gas before flowing out of the air preheater, and air-flue gas mixed gas with higher preheating temperature is obtained. Because part of the flue gas is mixed, the oxygen content in the preheated air is reduced, and the larger the mixed flue gas amount is, the lower the oxygen content in the preheated air is. As is well known, NOXGeneration is close to oxygen concentration in fuel combustion processIn relation to, the lower the oxygen concentration during combustion, NOXThe lower the generation. Therefore, the preheated air with low oxygen concentration is sent to the stokehole burner to support combustion in the furnace, and NO can be greatly inhibited in the fuel combustion process because the oxygen concentration in the fuel combustion process is reducedXGeneration and effective reduction of NO in the heating furnaceXAnd (5) discharging. Meanwhile, as the preheating temperature of the air mixture rises, the amount of hot gas entering the furnace to participate in heat exchange is increased, the technology also has the effect of improving the heat exchange strength of the hearth of the heating furnace, and the energy-saving effect of the air preheater is further improved.
The hot air collecting pipe is formed by arranging a plurality of rows of hot air pipes, the hot air nozzles are arranged at the outlet ends of one or more or all of the hot air pipes, and the hot air nozzles are determined according to the amount of smoke sucked. The larger the amount of the mixed flue gas is, the lower the oxygen content in the preheated air is, and the flue gas NO at the tail of the furnace isXThe lower the emissions. The heating furnace usually adopts various low NOXBurner to control combustion process to reduce NOXThe original generation amount, the technology directly reduces the oxygen concentration of combustion air participating in combustion and reduces NOXThe amplitude is larger, and the effect is more obvious. Even if low NO is usedXThe application of the burner on the heating furnace can still further reduce the NO of the tail flue gas of the furnaceXAnd (5) discharging.
The check valve is a butterfly check valve.
If a pressure measuring or component detecting analysis device is added, the gas preheater can be adopted under the condition that the linked control check valve ensures that no gas leaks into the flue.
Example one
The air preheater is arranged in a tail flue of a heating furnace, cold air is fed by a blower, enters from an inlet air box, is preheated by high-temperature flue gas through a cold air collecting pipe, a lower air box and a hot air collecting pipe, is sprayed out from a hot air nozzle, sucks the surrounding high-temperature flue gas through an ejector to form air-flue gas mixture, and finally is sent out from an outlet air box.
The hot air nozzle and the ejector of the air preheater are determined according to the amount of smoke sucked as required, the larger the amount of the mixed smoke is, the lower the oxygen content in the preheated air is, and the NO of the tail smoke of the furnace isXThe lower the emissions. While preheating the airWhen the oxygen content is reduced to below 15 percent, the NO of the flue gas at the tail of the furnaceXThe emission can be reduced to below 60mg/m3, which is far superior to the national standard requirement of ultralow emission less than 200mg/m 3.
Example two
When the oxygen content in the preheated air is reduced to below 10 percent, the NO of the flue gas at the tail of the furnaceXThe emission can be controlled below 30mg/m3, which is far superior to the national standard requirement of ultralow emission less than 200mg/m 3.
The air preheater has the advantages of higher air preheating temperature, better energy-saving effect, simple equipment structure and NO new operating cost, and can effectively reduce NO of the heating furnaceXAnd the emission is realized, the heat exchange strength of the hearth of the heating furnace is improved, and the good effects of energy conservation and emission reduction are achieved.
The present invention is illustrated by the above examples, and is not limited to the embodiments of the present invention, and the structure, the position arrangement and the connection of the components may be changed. On the basis of the present invention, any changes or equivalent changes of the individual components according to the principle of the present invention should not be excluded from the scope of the present invention.
Claims (6)
1. Can reduce heating furnace tail gas NOXThe discharged air preheater comprises an inlet air box, a cold air collecting pipe, a lower air box, a hot air collecting pipe and an outlet air box, wherein the inlet air box is connected with the inlet end of the cold air collecting pipe, the outlet end of the cold air collecting pipe is connected with the inlet end of the hot air collecting pipe through the lower air box, and the outlet end of the hot air collecting pipe is connected with the outlet air box.
2. The method of claim 1 for reducing NO in furnace off-gasXThe discharged air preheater is characterized in that the inlet end of the ejector is also provided withThe gas collecting head is arranged, the large head end of the gas collecting head faces outwards, and the small head end of the gas collecting head is connected with the inlet of the ejector.
3. The method according to claim 1 or 2 for reducing NO in furnace exhaust gasXAn exhaust air preheater, wherein said hot air manifold is comprised of an array of rows of hot air ducts, and said hot air nozzles are disposed at the outlet ends of one or more or all of said hot air ducts.
4. The method of claim 1 for reducing NO in furnace off-gasXA vented air preheater, wherein said check valve is a butterfly check valve.
5. The method of claim 2 for reducing NO in furnace off-gasXAn exhaust air preheater, wherein said collector head is a conical diverging duct structure.
6. Use of the composition of claim 3 for reducing NO in furnace off-gasXA method of using a vented air preheater, comprising:
the air preheater is arranged in a tail flue of a heating furnace, cold air is fed by a blower, enters from an inlet air box, is preheated by high-temperature flue gas after passing through a cold air collecting pipe, a lower air box and a hot air collecting pipe, is sprayed out from a hot air nozzle, sucks the surrounding high-temperature flue gas by an ejector to form air-flue gas mixture, and finally is sent out from an outlet air box.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110211436.5A CN112923391B (en) | 2021-02-25 | 2021-02-25 | Air preheater capable of reducing NOx emission of tail gas of heating furnace and using method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110211436.5A CN112923391B (en) | 2021-02-25 | 2021-02-25 | Air preheater capable of reducing NOx emission of tail gas of heating furnace and using method |
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| Publication Number | Publication Date |
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| CN112923391A true CN112923391A (en) | 2021-06-08 |
| CN112923391B CN112923391B (en) | 2023-03-14 |
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| CN202110211436.5A Active CN112923391B (en) | 2021-02-25 | 2021-02-25 | Air preheater capable of reducing NOx emission of tail gas of heating furnace and using method |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2689073Y (en) * | 2004-03-22 | 2005-03-30 | 江阴市石油化工设备有限公司 | High-temperature steel pipe effective air preheaters |
| JP2007101129A (en) * | 2005-10-06 | 2007-04-19 | Tokyo Gas Engineering Co Ltd | Heat storage type burner device and its operation method |
| CN205137451U (en) * | 2015-04-29 | 2016-04-06 | 王中 | Force to draw low NOx gas combustion ware of penetrating flue gas backward flow |
| CN211290049U (en) * | 2019-09-11 | 2020-08-18 | 向顺华 | Self-preheating type flue gas self-circulation type low-nitrogen non-oxidation burner |
-
2021
- 2021-02-25 CN CN202110211436.5A patent/CN112923391B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN2689073Y (en) * | 2004-03-22 | 2005-03-30 | 江阴市石油化工设备有限公司 | High-temperature steel pipe effective air preheaters |
| JP2007101129A (en) * | 2005-10-06 | 2007-04-19 | Tokyo Gas Engineering Co Ltd | Heat storage type burner device and its operation method |
| CN205137451U (en) * | 2015-04-29 | 2016-04-06 | 王中 | Force to draw low NOx gas combustion ware of penetrating flue gas backward flow |
| CN211290049U (en) * | 2019-09-11 | 2020-08-18 | 向顺华 | Self-preheating type flue gas self-circulation type low-nitrogen non-oxidation burner |
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| CN112923391B (en) | 2023-03-14 |
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