CN116989349A - Air preheater divides adjustable air supply of pipeline to preheat system - Google Patents
Air preheater divides adjustable air supply of pipeline to preheat system Download PDFInfo
- Publication number
- CN116989349A CN116989349A CN202210437785.3A CN202210437785A CN116989349A CN 116989349 A CN116989349 A CN 116989349A CN 202210437785 A CN202210437785 A CN 202210437785A CN 116989349 A CN116989349 A CN 116989349A
- Authority
- CN
- China
- Prior art keywords
- air
- rotor
- channels
- inlet
- preheater
- 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.)
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Links
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000003546 flue gas Substances 0.000 claims abstract description 29
- 230000007797 corrosion Effects 0.000 claims abstract description 18
- 238000005260 corrosion Methods 0.000 claims abstract description 18
- 238000010438 heat treatment Methods 0.000 claims abstract description 13
- 239000002184 metal Substances 0.000 claims abstract description 9
- 239000007789 gas Substances 0.000 claims abstract description 6
- 238000005192 partition Methods 0.000 claims description 16
- 239000000779 smoke Substances 0.000 claims description 9
- 238000000034 method Methods 0.000 claims description 5
- 239000003517 fume Substances 0.000 claims description 4
- 238000007789 sealing Methods 0.000 claims description 4
- 238000002485 combustion reaction Methods 0.000 description 7
- 239000002253 acid Substances 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 2
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
Classifications
-
- 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
- F23L15/02—Arrangements of regenerators
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F19/00—Preventing the formation of deposits or corrosion, e.g. by using filters or scrapers
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
- F28F27/02—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus for controlling the distribution of heat-exchange media between different channels
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Air Supply (AREA)
Abstract
The invention relates to an air preheater split-pipeline adjustable air supply preheating system, which comprises: the primary air inlet and the secondary air inlet of the air preheater and the flue gas inlet are respectively and equally divided into three air channels; a plurality of adjustable air doors are arranged at the inlet of each air duct; the heat transfer element of the primary air rotor heating area of the air preheater is equally divided into three annular areas with equal areas along the diameter direction; the three air channels are in one-to-one correspondence with the three annular areas and are independent and non-communicated channels; and controlling the inlet air quantity of the three air channels by using an adjustable air door. Air doors are respectively adjusted according to the air quantity required by different loads of the unit so as to control the air quantity; each air channel is controlled by an adjustable air door; the heat exchange capacity of the rotor heat transfer element and the primary air of the low-load air preheater is reduced, the exhaust gas temperature is increased, and the metal temperature of the rotor heat transfer element is increased, so that the problem of low-temperature corrosion of the air preheater is solved. Particularly, the invention can reduce the low-temperature corrosion speed in multiple times under the condition of low-load operation of the unit.
Description
Technical Field
The invention relates to the technical field of air preheaters of coal-fired power plants, in particular to an air preheating system with an adjustable air supply by branch pipelines of the air preheater.
Background
The air preheater of a coal-fired power plant is typically a heat exchange device that uses the heat of flue gas to heat the air required for combustion. Because the air preheater works in the area with the lowest smoke temperature, the heat of the smoke is recovered, and the smoke discharging temperature is reduced, so that the boiler efficiency is improved. Meanwhile, as the air is preheated, the initial temperature of the fuel and the air is increased, the ignition and combustion processes of the fuel are enhanced, the incomplete combustion loss of the fuel is reduced, and the boiler efficiency is further improved. In addition, the air preheating can also improve the temperature of flue gas in the hearth and strengthen the radiation heat exchange in the hearth. Therefore, air preheaters have become an important component of modern boilers.
When the flue gas enters the air preheater, the temperature of the flue gas is reduced or the flue gas contacts with metal of a heating surface with lower temperature, and when the wall temperature of the heating surface is close to or lower than the acid dew point of the flue gas, the sulfuric acid vapor in the flue gas can be condensed on the metal wall surface to generate acid corrosion on the wall surface. This corrosion is called low temperature corrosion. Intense low temperature corrosion typically occurs at the cold end of the air preheater, where the temperature of the air and flue gas is at a minimum. The corrosion causes the fracture perforation of the metal on the heating surface of the air preheater, so that a large amount of air leaks into the flue gas, the air supply is insufficient, the combustion in the boiler is deteriorated, the efficiency of the boiler is reduced, meanwhile, the accumulated ash is also aggravated by the corrosion, the resistance of the flue is increased, the output of the induced draft fan is insufficient, the maintenance of the negative pressure of the combustion chamber is influenced, and the safe and economic operation of the boiler is seriously influenced.
In summary, the reason for the low-temperature corrosion is that the flue gas contains sulfur trioxide and the temperature of the heated surface is lower than the dew point temperature of the acid, so that the main technical means for reducing and preventing the low-temperature corrosion is to raise the temperature of the wall surface of the heated surface to be higher than the dew point temperature of the flue gas. It is a more common method to increase the surface temperature of the heated surface by increasing the inlet air temperature of the air preheater. Hot air recirculation methods or warmers are typically used to raise the air preheater inlet air temperature. However, this method has a disadvantage in that the efficiency of the boiler is lowered.
At present, the load fluctuation of a thermal power plant is large, a boiler runs for a long time under low load, the exhaust gas temperature is low, and the low-temperature corrosion of the air preheater is further aggravated, so that the heating surface of the air preheater is damaged.
Disclosure of Invention
The invention aims to overcome the defects in the background technology and provide an air preheater split-pipeline adjustable air supply preheating system, which can divide primary air inlet, secondary air inlet and flue gas inlet of an air preheater into three air channels respectively, equally divide a heat transfer element of a primary air rotor heating area of the air preheater into three annular areas with equal area along the diameter direction, and the three air channels are in one-to-one correspondence with the three annular areas and are independent and non-communicated channels; the air inlet quantity of the three air channels is controlled by the adjustable air door, and the air inlet quantity is controlled by the adjustable air door according to different air quantities required by different loads of the unit, so that the heat exchange quantity of the rotor heat transfer element and primary air of the air preheater is reduced, the metal temperature of the rotor heat transfer element is increased, and the problem of low-temperature corrosion of the air preheater is solved.
The technical scheme of the invention is as follows:
an air preheater divides adjustable air supply of pipeline to preheat system, its characterized in that: it comprises the following steps: the primary air inlet and the secondary air inlet of the air preheater and the flue gas inlet are respectively and equally divided into three air channels; a plurality of adjustable air doors are arranged at the inlet of each air duct; the heat transfer element of the primary air rotor heating area of the air preheater is equally divided into three annular areas with equal areas along the diameter direction; the three air channels are in one-to-one correspondence with the three annular areas and are independent and non-communicated channels; and controlling the inlet air quantity of the three air channels by using an adjustable air door.
The primary air inlet, the secondary air inlet and the flue gas inlet are equally divided into three air channels; the three air channels are separated by a baffle plate; a plurality of adjustable air doors are arranged at the inlet of each air duct; the air inlet is controlled by adjusting the air door respectively according to different air volumes required by different loads of the unit. Especially, the low-load operation condition of the unit realizes the adjustment mode of controlling the air quantity in different bins and different areas.
The primary air inlet, the secondary air inlet and the flue gas inlet are respectively equally divided into three air channels, the three air channels are separated by a partition plate, a plurality of adjustable air doors are arranged at the inlet of each air channel, and the air inlet is respectively adjusted according to different air volumes required by different loads of the unit.
The heat transfer element of the primary air rotor heating area is equally divided into three annular areas with equal areas along the diameter direction, and the three annular areas are separated from top to bottom by a partition board and are mutually independent.
The three air channels are in one-to-one correspondence with the three annular areas, and the partition plates among the three air channels extend to the upper part of the annular areas all the time from the inlets of the primary air channels, the secondary air channels and the flue gas air channels to form three independent primary air channels, three secondary air channels or three flue gas channels so as to ensure that the wind of each air channel is isolated from each other.
The system controls the air quantity of the inlets of the three air channels by using the adjustable air door, and respectively adjusts the air door to control the air quantity according to different air quantities required by different loads of the unit, thereby reducing the heat exchange quantity between the rotor heat transfer element and the primary air of the low-load air preheater, improving the exhaust gas temperature, and improving the metal temperature of the rotor heat transfer element, and further relieving the problem of low-temperature corrosion of the air preheater.
According to the system, different air duct dividing modes can be selected according to different sizes and types of the air preheaters, and the system is not limited to three air ducts.
The system is applied to low-load operation conditions of the unit, realizes a mode of adjusting the control air quantity in a bin-division and region-division mode, improves the operation efficiency of the low-load unit, and realizes low-load stable combustion of the unit.
The invention has the advantages that: according to different load requirements of the unit, the heat exchange areas of primary air, secondary air and flue gas are adjusted, and especially the unit runs under low load, so that the heat exchange amount can be reduced, the exhaust gas temperature can be improved, and the low-temperature corrosion can be improved. Meanwhile, the low-load operation can be realized, the low-oxygen combustion can be realized by reducing the air quantity, and once the excess air coefficient is reduced to be below 1.03-1.05, the low-temperature corrosion speed of the air preheater is reduced by times.
Drawings
Fig. 1 is a schematic perspective view of a split-duct adjustable air supply preheating system of an air preheater according to embodiment 1 of the present invention.
Fig. 2 is a top view of the split duct adjustable supply air preheating system of the air preheater according to embodiment 1 of the present invention.
FIG. 3 is a cross-sectional view of a split duct adjustable supply air preheating system for an air preheater according to embodiment 1 of the present invention.
Fig. 4 is a bottom view of the split duct adjustable supply air preheating system of the air preheater according to embodiment 1 of the present invention.
Fig. 5 is a schematic view of a primary air duct partition of an air preheater split-duct adjustable air supply preheating system according to embodiment 1 of the present invention.
FIG. 6 is a schematic diagram of a rotor partition of an air preheater split duct adjustable supply preheating system in accordance with embodiment 1 of the present invention.
Reference numerals in the drawings:
a flue gas channel 1; a secondary air passage 2; a primary air duct 3; three air channels 301, 302, 303 of the primary air channel 3; a drive shaft 4; a rotor 5; a housing 6; an air duct partition 7; a rotor diaphragm 8; a sector plate 9; a damper 10.
Detailed Description
The present invention will be further described with reference to the drawings and example 1.
Example 1:
as shown in fig. 1-5, the present invention is an air preheater split-duct adjustable supply air preheating system, comprising: air heater, flue gas passageway 1, overgrate air passageway 2, primary air passageway 3, its characterized in that: the air preheater is provided with a driving shaft 4, a rotor 5, a shell 6, an air duct partition 7, a rotor partition 8, a sector plate 9 and an adjustable air door 10.
Wherein the air preheater is a three-bin rotary air preheater.
The flue gas channel 1, the secondary air channel 2 and the primary air channel 3 are respectively connected with a flue and an air channel of the boiler; and in the sealing area formed by the sealing device, neither smoke nor air flows, namely the smoke and the air are isolated from each other.
The rotor 5 is driven by a motor through the driving shaft 4 to rotate at a certain rotating speed, and the whole circumference heating surface of the rotor 5 continuously alternates and passes through the smoke and air circulation area. When the rotor 5 is turned to the fume circulation area, the fume transfers heat to the heat transfer element of the rotor 5; when the rotor 5 is turned into the air circulation area, the heat transfer elements of the rotor 5 transfer heat to the air flowing through. One heat exchange process is completed every one revolution.
The primary air duct 3 is arranged into three air ducts 301, 302 and 303 through an air duct partition 7 and is uniformly divided into channels with equal areas. Simultaneously, the secondary air channel 2 and the flue gas channel 1 are also uniformly divided into three channels with equal areas through the air channel partition plate 7.
Three primary air duct baffles 7 extend from the duct inlets to the upper part of the annular area of the rotor 5 to form three independent air ducts, so that the air of each air duct is isolated from each other.
The rotor partition 8 equally divides the rotor 5 into three channels of equal area. When the rotor 5 passes through the primary air area, three areas from inside to outside correspond to three air channels 301, 302 and 303 of the primary air channel 3 respectively.
The system utilizes an adjustable air door 10 to control the inlet air quantity of three independent air channels, and the air door 10 is respectively adjusted to control the air quantity according to different air quantities required by different loads of a unit; each air channel is controlled by 3 air doors; so as to reduce the heat exchange quantity of the heat transfer element of the rotor 5 of the low-load air preheater and the primary air, improve the exhaust gas temperature and improve the metal temperature of the heat transfer element of the rotor 5, thereby solving the problem of low-temperature corrosion of the air preheater.
The secondary air channel and the flue gas channel are divided into the same air channels at the same time, and the structure and the control mode are the same as those of the primary air.
The invention controls the cold air inlet quantity by a plurality of air doors in a stepped way, reduces the heat exchange quantity, thereby improving the metal temperature of the heat transfer element at the cold end of the rotor of the air preheater and solving the problem of low-temperature corrosion of the air preheater.
The invention is applied to the low-load operation condition of the unit, realizes the adjustment mode of controlling the air quantity in different bins and different areas, and improves the operation efficiency of the low-load unit.
The heating device can be applied to the three-bin air preheater and can be divided into two-bin air preheaters. Different air duct dividing modes can be selected according to different sizes of the air preheaters, and the air duct dividing mode is not limited to three air ducts.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the particular embodiments disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.
Claims (10)
1. An air preheater divides adjustable air supply of pipeline to preheat system, its characterized in that: it comprises the following steps: the primary air inlet and the secondary air inlet of the air preheater and the flue gas inlet are respectively and equally divided into three air channels; a plurality of adjustable air doors are arranged at the inlet of each air duct; the heat transfer element of the primary air rotor heating area of the air preheater is equally divided into three annular areas with equal areas along the diameter direction; the three air channels are in one-to-one correspondence with the three annular areas and are independent and non-communicated channels; and controlling the inlet air quantity of the three air channels by using an adjustable air door.
2. The air preheater split-duct adjustable supply air preheating system of claim 1, wherein: the primary air inlet, the secondary air inlet and the flue gas inlet are equally divided into three air channels which are separated by a partition plate; the air inlet is controlled by adjusting the air door respectively according to different air volumes required by different loads of the unit.
3. The air preheater split-duct adjustable supply air preheating system of claim 1, wherein: the heat transfer element of the primary air rotor heating area is equally divided into three annular areas with equal areas along the diameter direction, and the three annular areas are separated from top to bottom by a partition board and are mutually independent.
4. The air preheater split-duct adjustable supply air preheating system of claim 1, wherein: the three air channels are in one-to-one correspondence with the three annular areas; the partition plate between the three air channels extends from the air channel inlet or the flue inlet to the upper part of the annular area to form three independent primary air channels, three secondary air channels or three flue gas channels so as to ensure that the wind of each air channel is isolated from each other.
5. An air preheater split-duct adjustable supply air preheating system, comprising: air heater, flue gas passageway, overgrate air passageway, primary air passageway, its characterized in that: the flue gas channel, the secondary air channel and the primary air channel are respectively connected with a flue and an air channel of the boiler; and in the sealing area formed by the sealing device, neither smoke nor air flows, namely the smoke and the air are isolated from each other; the air preheater is provided with a driving shaft, a rotor and a shell; and is provided with an air duct baffle, a rotor baffle, a sector plate and an adjustable air door.
6. The air preheater split duct adjustable supply air preheating system as set forth in claim 5, wherein: the rotor is driven by the motor through the driving shaft and rotates at a certain rotating speed, and the whole circumference heating surface of the rotor continuously alternates and passes through the smoke and air circulation area; when the rotor rotates to the fume circulation area, the fume transmits heat to the heat transfer element of the rotor; when the rotor turns to the air circulation area, the heat transfer element of the rotor transfers heat to the air flowing through; one heat exchange process is completed every one revolution.
7. The air preheater split duct adjustable supply air preheating system as set forth in claim 5, wherein: the primary air channel is uniformly divided into channels with equal areas by the air channel partition plates.
8. The air preheater split duct adjustable supply air preheating system as set forth in claim 5, wherein: the three primary air duct baffles extend from the duct inlets to the upper part of the annular area of the rotor to form three independent air ducts, so that each air duct is isolated from each other.
9. The air preheater split duct adjustable supply air preheating system as set forth in claim 5, wherein: the rotor partition plate divides the rotor into three channels with equal areas; when the rotor passes through the primary air area, the three areas from inside to outside correspond to the three air channels of the primary air channel respectively.
10. The air preheater split duct adjustable supply air preheating system as set forth in claim 5, wherein: the inlet air quantity of the three independent air channels is controlled through the adjustable air door; air doors are respectively adjusted according to the air quantity required by different loads of the unit so as to control the air quantity; each air channel is controlled by an adjustable air door; the heat exchange capacity of the rotor heat transfer element and the primary air of the low-load air preheater is reduced, the exhaust gas temperature is increased, and the metal temperature of the rotor heat transfer element is increased, so that the low-temperature corrosion of the air preheater is improved.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210437785.3A CN116989349A (en) | 2022-04-25 | 2022-04-25 | Air preheater divides adjustable air supply of pipeline to preheat system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210437785.3A CN116989349A (en) | 2022-04-25 | 2022-04-25 | Air preheater divides adjustable air supply of pipeline to preheat system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116989349A true CN116989349A (en) | 2023-11-03 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210437785.3A Pending CN116989349A (en) | 2022-04-25 | 2022-04-25 | Air preheater divides adjustable air supply of pipeline to preheat system |
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| CN (1) | CN116989349A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118242664A (en) * | 2024-04-03 | 2024-06-25 | 华能威海发电有限责任公司 | Air preheater dust treatment device for power station boiler |
-
2022
- 2022-04-25 CN CN202210437785.3A patent/CN116989349A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN118242664A (en) * | 2024-04-03 | 2024-06-25 | 华能威海发电有限责任公司 | Air preheater dust treatment device for power station boiler |
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