CN210801252U - Air preheater prevents stifled and reinforcing heat transfer device - Google Patents
Air preheater prevents stifled and reinforcing heat transfer device Download PDFInfo
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- CN210801252U CN210801252U CN201921053451.6U CN201921053451U CN210801252U CN 210801252 U CN210801252 U CN 210801252U CN 201921053451 U CN201921053451 U CN 201921053451U CN 210801252 U CN210801252 U CN 210801252U
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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 utility model discloses an air preheater anti-blocking and enhanced heat transfer device, which comprises a surface heat exchanger, wherein a flue gas channel and an air channel are arranged in the surface heat exchanger, the inlet of the flue gas channel is communicated with the inlet flue of the air preheater through an inlet branch flue, and the outlet of the flue gas channel is communicated with the outlet flue of the air preheater through an outlet branch flue; the inlet of the air channel is communicated with the inlet air channel, and the outlet of the air channel is communicated with the outlet air channel; the air conditioner further comprises a serial air channel used for communicating the outlet air channel with the cold air pipeline, and a parallel air channel used for communicating the outlet air channel with the hot air pipeline, wherein a first baffle door and a second baffle door are respectively arranged on the serial air channel and the parallel air channel. The device can switch to series, parallel or series-parallel mixed mode, can improve air preheater air inlet temperature and cold junction metal temperature, prevents and controls the stifled ash of air preheater, improves the clean degree of air preheater heat transfer element to reduce exhaust gas temperature, improve boiler efficiency.
Description
Technical Field
The utility model belongs to the technical field of boiler flue gas waste heat utilization, concretely relates to air preheater prevents stifled and reinforcing heat transfer device.
Background
The rotary air preheater is widely applied to thermal power boilers with the capacity grade of more than 200MW, and is a large round barrel with an upper opening and a lower opening, radiating fins are densely arranged in the large round barrel, smoke flows from top to bottom, heat carried by the smoke is absorbed by the radiating fins, and the heated radiating fins move to the air side along with the slow rotation of the air preheater; the air flows from bottom to top, and is preheated to a certain temperature after absorbing the heat of the radiating fins. The temperature of the smoke and the air at the upper end of the air preheater is high and is called as a hot end, and the temperature of the smoke and the air at the lower end of the air preheater is low and is called as a cold end.
The comprehensive temperature of the cold end of the air preheater is the sum of the temperature of the smoke at the outlet of the air preheater (namely the temperature of the exhaust smoke) and the temperature of the cold air at the inlet. Under the conditions of low load and low environmental temperature of the boiler, the comprehensive temperature of the cold end of the air preheater is lower, and the metal temperature of the cold end is lower than the dew point of the flue gas, namely SO in the flue gas3The condensation temperature of the sulfuric acid steam formed with the water vapor causes the sulfuric acid steam to condense on the heating surface of the air preheater and a tail flue, and fly ash in the flue gas is adhered to cause low-temperature corrosion and ash blockage at the cold end.
In addition, the current flue gas denitration mainly adopts a Selective Catalytic Reduction (SCR) technology, and in order to ensure the SCR denitration efficiency, ammonia gas must have a certain excess coefficient to form escaping ammonia. The ammonia and SO in the flue gas escape along with the reduction of the temperature of the flue gas to a certain degree3The ammonium bisulfate with strong caking property is generated by the reaction and is adhered on the heat exchange element of the air preheater and is bonded with fly ash, thus causing the blockage of the air preheater.
The ash blockage of the air preheater has many hazards: on one hand, the cleanliness of a heat exchange element is reduced, the heat exchange effect is poor, and the boiler efficiency is reduced; on the other hand, the power consumption of the fan is increased, and the fan may be forced to limit load or even stop running due to insufficient fan margin in serious conditions.
In order to solve the problem, the traditional method is hot air recirculation, and the comprehensive temperature of the cold end entering the air preheater is improved by a mode of extracting high-temperature air from a hot air pipeline of the air preheater and refluxing the high-temperature air to the inlet of a blower.
A steam air heater is improved on a boiler in part of power plants, the air heater is arranged on a cold air duct at the inlet of the air preheater, a heat source comes from a steam turbine to extract steam, and the comprehensive temperature of the cold end of the air preheater can be improved under the working condition in winter. But the exhaust gas temperature is increased, the steam extraction and power-applying capacity of the steam turbine is lost, the air duct resistance is increased, and the like, so that the running economy of the unit is reduced.
And the other method is to modify the flue gas waste heat air heater, install the air heater on the cold air duct at the inlet of the air preheater, install the flue gas cooler on the flue at the outlet of the air preheater, and connect the air heater and the flue gas cooler in series by using closed type heat medium water circulation, so as to realize indirect heating of air by flue gas and improve the comprehensive temperature of the cold end of the air preheater. The air heater system can be put into operation for a long time, the exhaust gas temperature cannot be increased, but because the heat exchangers are arranged in the air channel and the flue in series, the resistance of the air side and the resistance of the flue side are increased, so that the greater resistance loss is caused, and the power consumption of the fan is increased. On the other hand, although the corrosion and the dust deposition of the air preheater are improved, the corrosion and the dust deposition of the flue gas cooler behind the air preheater are difficult to avoid.
SUMMERY OF THE UTILITY MODEL
On solving air preheater corruption, stifled grey scheduling problem, current method all is difficult to compromise and improves effect and economic nature, for overcoming this defect, the utility model provides an air preheater prevents stifled and reinforcing heat transfer device. The specific implementation mode is as follows:
the device comprises a surface type heat exchanger, an inlet branch flue, an outlet branch flue, an inlet air duct, an outlet air duct, a serial air duct and a parallel air duct;
a smoke channel and an air channel are arranged in the surface type heat exchanger, the inlet of the smoke channel is communicated with the inlet flue of the air preheater through the inlet branch flue, and the outlet of the smoke channel is communicated with the outlet flue of the air preheater through the outlet branch flue; the inlet of the air channel is communicated with the inlet air channel, and the outlet of the air channel is communicated with the outlet air channel;
the serial air duct is used for communicating the outlet air duct with a cold air pipeline of the air preheater, and a first baffle door is arranged on the serial air duct;
the parallel air duct is used for communicating the outlet air duct with a hot air pipeline of the air preheater, and a second baffle door is arranged on the parallel air duct.
Preferably, a third baffle door is arranged on the inlet branch flue, a fourth baffle door is arranged on the outlet branch flue, and the third baffle door and the fourth baffle door are both adjustable baffle doors.
Preferably, the first flapper door and the second flapper door are both adjustable flapper doors.
Preferably, the inlet branch flue, the outlet branch flue, the inlet air duct and the outlet air duct are all provided with temperature measuring points and pressure measuring points.
Preferably, a booster fan is arranged on the inlet air duct.
Preferably, an ash hopper is arranged between the inlet branch flue and the inlet flue of the air preheater.
Preferably, the surface heat exchanger is a plate heat exchanger.
The utility model relates to an embodiment's beneficial effect:
the surface type heat exchanger is added on the smoke side of the air preheater, cold air can be sent into a cold air pipeline at the inlet of the air preheater through a serial air channel after being heated by the surface type heat exchanger, and can also be sent into a hot air pipeline at the outlet of the air preheater through a parallel air channel, and the opening and closing of a first baffle door on the serial air channel and a second baffle door on the parallel air channel can be switched to a serial, parallel or serial-parallel mixed mode by controlling, so that the air preheater operates in a parallel mode under the working conditions of high load and high ambient temperature of the unit, the smoke exhaust temperature and the air side resistance of the air preheater are reduced, and the operation economy of the unit is; the working conditions of low load and low environmental temperature of the unit adopt a serial mode, the cold end metal temperature of the air preheater is improved, cold end corrosion dust deposition and ammonium bisulfate bonding dust deposition are prevented, and a serial-parallel mixing mode is selected in the middle working condition, so that the optimal operation effect is achieved. This scheme can effectively improve air preheater air inlet temperature and cold junction metal temperature, and the stifled ash of prevention and control air preheater improves the clean degree of air preheater heat transfer element to reduce the temperature of discharging fume, improve boiler efficiency.
Drawings
FIG. 1 is a schematic structural diagram of an apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of an apparatus according to another embodiment of the present invention;
in the figure: 1-a blower; 2-a cold air duct; 3-an air preheater; 4-hot air pipes; 5-inlet flue; 6-outlet flue; 7-surface heat exchanger; 8-inlet branch flue; 9-ash bucket; 10-a third shutter door; 11-an outlet branch flue; 12-a fourth flapper door; 13-a booster fan; 14-inlet duct; 15-outlet duct; 16-a serial air duct; 17-a first flapper door; 18-parallel air ducts; 19-a second shutter door; 20-blast pipe.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
In the description of the present invention, greater than or equal to is understood as not including the present number, the above and the like are understood as including the present number, and the first, the second, the third and the fourth are only used for distinguishing the technical features, but not for indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the precedence of the indicated technical features.
The anti-blocking and heat transfer enhancement device of the air preheater shown in fig. 1 is provided with a surface type heat exchanger 7 beside the air preheater 3. Cold air enters from an air supply pipe 20, is pressurized by an air blower 1, enters an air preheater 3 from bottom to top through a cold air pipeline 2, is heated and heated, and is discharged to a boiler from a hot air pipeline 4; the high-temperature flue gas enters the air preheater 3 from top to bottom through the inlet flue 5, is cooled and then is discharged through the outlet flue 6.
A smoke channel and an air channel are arranged in the surface type heat exchanger 7. The inlet of the flue gas channel is communicated with the inlet flue 5 of the air preheater 3 through an inlet branch flue 8, and the outlet of the flue gas channel is communicated with the outlet flue 6 of the air preheater 3 through an outlet branch flue 11. The inlet of the air passage communicates with an inlet duct 14 and the outlet of the air passage communicates with an outlet duct 15. Expansion joints (not shown) are provided on the inlet branch flues 8, the outlet branch flues 11, the inlet air ducts 14 and the outlet air ducts 15.
The air conditioner also comprises a serial air duct 16 and a parallel air duct 18, wherein one end of the serial air duct 16 is communicated with the outlet air duct 15, the other end of the serial air duct 16 is communicated with the cold air pipeline 2 of the air preheater 3, and a first baffle door 17 is arranged on the serial air duct 16. One end of the parallel air duct 18 is communicated with the outlet air duct 15, the other end of the parallel air duct 18 is communicated with the hot air pipeline 4 of the air preheater 3, and a second baffle plate door 19 is arranged on the parallel air duct 18. By controlling the opening and closing of first flapper door 17 and second flapper door 19, switching to serial, parallel, or serial-parallel hybrid modes is possible. Because the inlet branch flue 8 is arranged to divide the flue gas of the inlet flue 5, the resistance of the flue gas side of the air preheater 3 is reduced. Under the working conditions of high load and high environmental temperature of the unit, the unit can operate in a parallel mode, air is heated through the surface heat exchanger 7, and the heated air is directly sent into the hot air pipeline 4 at the outlet of the air preheater 3, so that the smoke exhaust temperature and the air side resistance of the air preheater 3 can be reduced, and the operation economy of the unit is improved; the air preheater is operated in a serial mode under the working conditions of low load and low environmental temperature, heated air is directly sent into the cold air pipeline 2 at the inlet of the air preheater 3, the metal temperature at the cold end of the air preheater 3 is increased, and cold end corrosion dust deposition and ammonium bisulfate bonding dust deposition are prevented. And a series-parallel mixing mode is selected in the middle working condition, so that the optimal operation effect is achieved. This scheme can effectively improve 3 air inlet temperature of air preheater and cold junction metal temperature, and 3 stifled ashes of prevention and control air preheater improve 3 heat exchange element clean degrees of air preheater, can also reduce the temperature of discharging fume, improve boiler efficiency.
In a preferred embodiment, a third baffle door 10 is arranged on the inlet branch flue 8, a fourth baffle door 12 is arranged on the outlet branch flue 11, the first baffle door to the fourth baffle door are all adjustable baffle doors, and the distribution of flue gas and air flow can be changed according to actual conditions by adjusting the opening degree of each baffle door, so that the metal temperature at the cold end of the air preheater 3 can be adjusted. For this purpose, temperature measuring points (not shown) and pressure measuring points (not shown) may be provided on the inlet branch flue 8, the outlet branch flue 11, the inlet air duct 14, and the outlet air duct 15.
In practical application, as the fly ash concentration in the flue gas of the coal-fired boiler is high, the granularity of part of the fly ash with strong coking property is large, the heat exchange elements of the air preheater 3 are corrugated plates which are densely arranged, and when low-temperature corrosion dust accumulation occurs at the cold end or ammonium bisulfate hardening occurs at the middle section, large-particle fly ash is difficult to smoothly pass through, so that the blockage process is aggravated. Therefore, an ash hopper 9 is arranged between the inlet branch flue 8 and the inlet flue 5 of the air preheater 3, and large-particle ash particles are separated from the flue gas by utilizing the gravity and inertia separation principle, so that the blockage of the air preheater 3 is delayed and alleviated. The surface type heat exchanger 7 is generally a tubular or plate type heat exchanger, preferably a plate type heat exchanger, the flue gas channel is smooth and has no wave, and the distance between the plates is larger than the clearance between the radiating fins of the air preheater 3, so that ash blockage is not easy to happen.
In this embodiment, the inlet duct 14 is provided with the booster fan 13, and the cold air is boosted by the booster fan 13 and then delivered to the surface heat exchanger 7 through the inlet duct 14, as shown in fig. 1.
In addition, the inlet duct 14 may be connected to the cold air duct 2 of the air pre-heater 3, and the serial duct 16 is connected to the cold air duct 2 through the blast pipe 20, as shown in fig. 2. In contrast to the embodiment shown in fig. 1, this embodiment does not require the booster fan 13.
The air preheater 3 is not particularly limited in type, and is suitable for a two-bin type air preheater or a multi-bin type air preheater with more than three bins, and preferably, the inlet air duct 14 is communicated with the inlet cold air pipes of the respective bins for the multi-bin type air preheater.
Claims (7)
1. The utility model provides an air preheater prevents stifled and reinforcing heat transfer device which characterized in that: the device comprises a surface type heat exchanger, an inlet branch flue, an outlet branch flue, an inlet air duct, an outlet air duct, a serial air duct and a parallel air duct;
a smoke channel and an air channel are arranged in the surface type heat exchanger, the inlet of the smoke channel is communicated with the inlet flue of the air preheater through the inlet branch flue, and the outlet of the smoke channel is communicated with the outlet flue of the air preheater through the outlet branch flue; the inlet of the air channel is communicated with the inlet air channel, and the outlet of the air channel is communicated with the outlet air channel;
the serial air duct is used for communicating the outlet air duct with a cold air pipeline of the air preheater, and a first baffle door is arranged on the serial air duct;
the parallel air duct is used for communicating the outlet air duct with a hot air pipeline of the air preheater, and a second baffle door is arranged on the parallel air duct.
2. The anti-blocking and enhanced heat transfer device of air preheater of claim 1, wherein said inlet branch flue is provided with a third baffle door, said outlet branch flue is provided with a fourth baffle door, and said third baffle door and said fourth baffle door are both adjustable baffle doors.
3. The air preheater blockage prevention and enhanced heat transfer device of claim 1 or 2, wherein said first baffle door and said second baffle door are both adjustable baffle doors.
4. The air preheater anti-blocking and heat transfer enhancement device according to claim 1, wherein the inlet branch flue, the outlet branch flue, the inlet air duct and the outlet air duct are all provided with temperature measuring points and pressure measuring points.
5. The air preheater anti-blocking and enhanced heat transfer device according to claim 1, wherein a booster fan is disposed on the inlet duct.
6. The anti-blocking and heat transfer enhancement device for the air preheater according to claim 1, wherein an ash hopper is arranged between the inlet branch flue and the inlet flue of the air preheater.
7. The anti-blocking and enhanced heat transfer device of air preheater of claim 1, wherein said surface heat exchanger is a plate heat exchanger.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921053451.6U CN210801252U (en) | 2019-07-05 | 2019-07-05 | Air preheater prevents stifled and reinforcing heat transfer device |
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| CN201921053451.6U CN210801252U (en) | 2019-07-05 | 2019-07-05 | Air preheater prevents stifled and reinforcing heat transfer device |
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| CN210801252U true CN210801252U (en) | 2020-06-19 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110397947A (en) * | 2019-07-05 | 2019-11-01 | 湖南大唐节能科技有限公司 | A kind of air preheater is anti-blocking and enhances heat transfer unit (HTU) |
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2019
- 2019-07-05 CN CN201921053451.6U patent/CN210801252U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110397947A (en) * | 2019-07-05 | 2019-11-01 | 湖南大唐节能科技有限公司 | A kind of air preheater is anti-blocking and enhances heat transfer unit (HTU) |
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