CN110779036A - System and method for heating primary air, water supply and circulating water by using bypass flue gas - Google Patents
System and method for heating primary air, water supply and circulating water by using bypass flue gas Download PDFInfo
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- CN110779036A CN110779036A CN201911142147.3A CN201911142147A CN110779036A CN 110779036 A CN110779036 A CN 110779036A CN 201911142147 A CN201911142147 A CN 201911142147A CN 110779036 A CN110779036 A CN 110779036A
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 209
- 239000003546 flue gas Substances 0.000 title claims abstract description 209
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 147
- 238000010438 heat treatment Methods 0.000 title claims abstract description 38
- 238000000034 method Methods 0.000 title claims abstract description 16
- 239000003245 coal Substances 0.000 claims description 19
- 238000012805 post-processing Methods 0.000 claims description 9
- 230000004907 flux Effects 0.000 claims description 3
- 239000002918 waste heat Substances 0.000 abstract description 15
- 238000004134 energy conservation Methods 0.000 abstract description 4
- 230000007613 environmental effect Effects 0.000 abstract description 4
- 239000008236 heating water Substances 0.000 abstract description 2
- 230000002349 favourable effect Effects 0.000 abstract 1
- 238000002485 combustion reaction Methods 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000003507 refrigerant Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES
- F23J15/00—Arrangements of devices for treating smoke or fumes
- F23J15/06—Arrangements of devices for treating smoke or fumes of coolers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
- F23K3/02—Pneumatic feeding arrangements, i.e. by air blast
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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
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D15/00—Other domestic- or space-heating systems
- F24D15/02—Other domestic- or space-heating systems consisting of self-contained heating units, e.g. storage heaters
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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
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Air Supply (AREA)
Abstract
The invention discloses a system and a method for heating primary air, water supply and circulating water by using bypass flue gas, wherein a hot flue gas outlet of a coal-fired boiler of the system is divided into a hot flue gas main path and a hot flue gas bypass; the hot flue gas main path is communicated with a flue gas chamber of the three-chamber preheater, and the flue gas chamber is communicated with the cold flue gas main path; a baffle door is arranged on the hot flue gas bypass and is sequentially communicated with a water supply heat exchanger, a high-temperature primary air heat exchanger, a circulating water heat exchanger of a fan heater and a low-temperature primary air heat exchanger; the low-temperature primary air heat exchanger is communicated with the cold flue gas bypass; wherein, the water supply heat exchanger is used for heating water, the low-temperature primary air heat exchanger and the high-temperature primary air heat exchanger are used for heating cold primary air, and the water pipe and the air heater circulating water heat exchanger are used for heating circulating water. The method comprises the following steps: the water supply, the primary air and the circulating water are simultaneously heated by using the waste heat of the bypass flue gas. The utilization of the flue gas waste heat is greatly improved, and the method is more favorable for environmental protection, energy conservation and cost reduction.
Description
Technical Field
The invention relates to a system and a method, in particular to a system and a method for heating primary air, water supply and circulating water by using bypass flue gas.
Background
The air preheater is one of the important components of the pulverized coal boiler system, and plays the roles of reducing the exhaust gas temperature, improving the temperature of air for combustion, enabling fuel to easily catch fire, enabling combustion to be stable and improving the combustion efficiency. The air preheater mainly comprises a trisection bin and a shell-and-tube type. At present, over 90 percent of coal-fired boilers of power stations adopt three-bin air preheaters, and hot flue gas, primary air and secondary air respectively circulate in three bins. In the existing pulverized coal boiler system, high-temperature flue gas generated by a coal-fired boiler is mainly sent into a three-bin air preheater to heat air for combustion (namely secondary air), and the heat of the high-temperature flue gas is sufficient for heating the secondary air, so that the energy is wasted; meanwhile, the flue gas waste heat of the bypass cannot be fully utilized in a gradient manner, so that energy waste is caused, environmental protection and energy conservation are not facilitated, and a system and a method which can effectively heat primary air, water supply and circulating water of the air heater at the same time do not exist, so that a large amount of energy is consumed to heat the primary air, the water supply and the circulating water of the air heater, and the operation cost is increased to a certain extent.
Disclosure of Invention
In order to solve the defects of the technology, the invention provides a system and a method for heating primary air, water supply and circulating water by using bypass flue gas.
In order to solve the technical problems, the invention adopts the technical scheme that: the system for heating primary air, water supply and circulating water by using bypass flue gas comprises a three-compartment preheater, a water supply heat exchanger, a high-temperature primary air heat exchanger, a circulating water heat exchanger of a fan heater, a low-temperature primary air heat exchanger and a fan heater;
the three-bin preheater is communicated with a coal-fired boiler, a hot flue gas outlet is arranged at the coal-fired boiler, and the hot flue gas outlet is divided into a hot flue gas main path and a hot flue gas bypass at the inlet of the three-bin preheater;
the main branch flue gas main path is communicated with the main branch flue gas main path, the main branch flue gas main path enters the main branch flue gas main path, and the main branch flue gas main path is communicated with a flue gas subsequent treatment device;
the hot flue gas bypass is provided with a baffle door which is communicated with the water supply heat exchanger, the baffle door is positioned between the hot flue gas bypass and the water supply heat exchanger, the high-temperature primary air heat exchanger, the air heater circulating water heat exchanger and the low-temperature primary air heat exchanger are communicated in sequence; the low-temperature primary air heat exchanger is communicated with a cold flue gas bypass, hot flue gas flowing through the hot flue gas bypass sequentially passes through the baffle door, the water supply heat exchanger, the high-temperature primary air heat exchanger, the air heater circulating water heat exchanger and the low-temperature primary air heat exchanger and releases heat, the hot flue gas passing through the hot flue gas bypass is changed into bypass cold flue gas to enter the cold flue gas bypass, and the cold flue gas bypass is also communicated with a flue gas subsequent treatment device;
the water supply heat exchanger is communicated with a water supply pipe at one side and communicated with an economizer at the other side, and the water supply enters the economizer after being absorbed in the water supply heat exchanger; the low-temperature primary air heat exchanger is communicated with a cold primary air inlet pipe at one side and is communicated with a middle primary air pipe at the other side, the low-temperature primary air heat exchanger is communicated with the high-temperature primary air heat exchanger through the middle primary air pipe, the high-temperature primary air heat exchanger is communicated with a hearth, and cold primary air firstly absorbs heat through the low-temperature primary air heat exchanger and then enters the high-temperature primary air heat exchanger to be heated and then enters the coal mill;
the circulating water inlet pipe of the air heater and the circulating water outlet pipe of the air heater are respectively communicated with the air heater; the air heater is communicated with a cold secondary air inlet pipe at one side and a warm secondary air outlet pipe at the other side, the warm secondary air outlet pipe is divided into two paths, one path is communicated with the primary air chamber of the three-chamber preheater, the other path is communicated with the secondary air chamber of the three-chamber preheater, the cold secondary air is changed into warm secondary air after heat exchange of the air heater, and the warm secondary air is heated by the primary air chamber and the secondary air chamber respectively and then is converged into outlet hot secondary air; the outlet pipes of the primary air chamber and the secondary air chamber are converged to form a hot secondary air outlet pipe, and the hot secondary air outlet pipe is also communicated with the hearth.
Furthermore, a shell-and-tube heat exchanger is adopted for both the high-temperature primary air heat exchanger and the low-temperature primary air heat exchanger.
Furthermore, the economizer and the hearth are both positioned at the coal-fired boiler.
A heating method of a system for heating primary air, water supply and circulating water by using bypass flue gas comprises the following specific steps:
high-temperature hot flue gas generated by the coal-fired boiler is divided into two paths, wherein one path enters a hot flue gas main path, and the other path enters a hot flue gas bypass; the hot flue gas entering the hot flue gas main path flows through the flue gas chamber of the three-chamber preheater to release heat and is changed into main path cold flue gas, the released heat enters the secondary air chamber and the primary air chamber, and the main path cold flue gas flows through the cold flue gas main path and then enters the flue gas subsequent treatment device to be subsequently treated by the flue gas subsequent treatment device;
the hot flue gas entering the hot flue gas bypass adjusts the flux through the baffle door, passes through the water supply heat exchanger, the high-temperature primary air heat exchanger, the air heater circulating water heat exchanger and the low-temperature primary air heat exchanger in sequence, releases heat, enters the cold flue gas bypass after releasing heat to become bypass cold flue gas, and the bypass cold flue gas also enters the flue gas post-treatment device to be subjected to post-treatment by the flue gas post-treatment device;
when hot flue gas of the hot flue gas bypass flows through the water supply heat exchanger, water is introduced into the water supply heat exchanger through the water supply pipe, the water enters the economizer after absorbing heat, and the economizer continues to heat the water supply;
when hot flue gas of a hot flue gas bypass flows through a high-temperature primary air heat exchanger and a low-temperature primary air heat exchanger, cold primary air firstly flows into the low-temperature primary air heat exchanger through a cold primary air inlet pipe, the cold primary air absorbs heat in the low-temperature primary air heat exchanger and then enters an intermediate primary air pipe to become intermediate primary air, the intermediate primary air continuously flows into the high-temperature primary air heat exchanger to further absorb heat and raise temperature to become hot primary air, and the hot primary air finally enters a coal mill;
when hot flue gas of the hot flue gas bypass flows through the circulating water heat exchanger of the air heater, cold secondary air enters the air heater through the cold secondary air inlet pipe, the circulating water heat exchanger of the air heater provides a heating medium for the air heater through the circulating water outlet pipe of the air heater, the cold secondary air is heated by the heating medium in the air heater to become hot secondary air, and the heat medium after heat exchange continuously enters the circulating water heat exchanger of the air heater through the circulating water outlet pipe of the air heater to absorb heat, so that the heating medium is continuously provided for the air heater; meanwhile, the warm secondary air flows into the primary air bin and the secondary air bin through the warm secondary air outlet pipe respectively to be reheated, and then is converged into outlet hot secondary air at the hot secondary outlet pipe after being heated, and the outlet hot secondary air is discharged into the hearth through the hot secondary outlet pipe.
The invention discloses a system and a method for heating primary air, water supply and circulating water by using bypass flue gas, wherein the system and the method disclosed by the invention simultaneously heat the primary air, the water supply and the circulating water of a fan heater by using the waste heat of the bypass flue gas, realize the step utilization of the waste heat of the flue gas, greatly improve the utilization of the waste heat of the flue gas, and are more beneficial to environmental protection and energy conservation, and simultaneously reduce the energy loss for heating the primary air, the water supply and the circulating water of the fan heater, and reduce the operation cost of a pulverized coal boiler system to a certain extent.
Drawings
FIG. 1 is a schematic diagram of a system for heating primary air, water supply and circulating water by using bypass flue gas according to the present invention.
In the figure: 1. a coal-fired boiler; 2. a hot flue gas bypass; 3. a hot flue gas main path; 4. a three-bin preheater; 5. a primary air plenum; 6. a secondary air chamber; 7. a flue gas chamber; 8. a hot secondary air outlet pipe; 9. a warm secondary air outlet pipe; 10. a cold flue gas main path; 11. a flapper door; 12. a feedwater heat exchanger; 13. a high-temperature primary air heat exchanger; 14. a circulating water heat exchanger of the air heater; 15. a low-temperature primary air heat exchanger; 16. a coal economizer; 17. a hearth; 18. SCR; 19. a circulating water outlet pipe of the air heater; 20. a cold primary air inlet pipe; 21. a cold flue gas bypass; 22. a warm air blower; 23. a cold secondary air inlet pipe; 24. a flue gas subsequent treatment device; 25. a circulating water outlet pipe of the air heater; 26. a middle primary air pipe; 27. a water supply pipe; 28. provided is a coal mill.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
A system for heating primary air, water supply and circulating water by using bypass flue gas comprises a trisection bin preheater 4, a water supply heat exchanger 12, a high-temperature primary air heat exchanger 13, a circulating water heat exchanger 14 of a fan heater, a low-temperature primary air heat exchanger 15 and a fan heater 22 as shown in figure 1.
The system for heating primary air, water supply and circulating water by using bypass flue gas is built on the basis of the existing pulverized coal boiler system, wherein a three-bin preheater 4 is communicated with a coal-fired boiler 1, an SCR18 is arranged at the position of the coal-fired boiler 1, and hot flue gas at the outlet of an SCR18 is divided into a hot flue gas main path 3 and a hot flue gas bypass 2 at the inlet of the three-bin preheater 4; and a primary air chamber 5, a secondary air chamber 6 and a flue gas chamber 7 which are communicated with each other are arranged in the three-chamber preheater 4.
For the main hot flue gas path 3, the main hot flue gas path is communicated with the flue gas chambers 7 of the three-chamber preheater 4, the flue gas chambers 7 are communicated with the main cold flue gas path 10, therefore, hot flue gas flowing through the main hot flue gas path 3 is changed into main cold flue gas after heat release in the flue gas chambers 7, the main cold flue gas enters the main cold flue gas path 10, the main cold flue gas path 10 is communicated with the flue gas post-processing device 24, the main cold flue gas is subjected to post-processing by the flue gas post-processing device 24, and safe emission of the flue gas is realized. The heat of the hot flue gas released in the flue gas chamber 7 is circulated to the secondary air chamber 6 and the primary air chamber 5 to heat the entering secondary air, and high-temperature outlet hot secondary air is obtained.
For the hot flue gas bypass 3, in order to realize the sufficient ladder utilization of the waste heat of the bypass flue gas, firstly, a baffle door 11 is installed on the hot flue gas bypass 3, and the flue gas quantity of the circulating hot flue gas bypass 3 is adjusted through the baffle door 11. Meanwhile, the hot flue gas bypass 3 is communicated with a water supply heat exchanger 12, a baffle door 11 is positioned between the hot flue gas bypass 3 and the water supply heat exchanger 12, the high-temperature primary air heat exchanger 13, the air heater circulating water heat exchanger 14 and the low-temperature primary air heat exchanger 15 are sequentially communicated, so that hot flue gas flowing through the hot flue gas bypass 3 sequentially passes through the water supply heat exchanger 12, the high-temperature primary air heat exchanger 13, the air heater circulating water heat exchanger 14 and the low-temperature primary air heat exchanger 15 after the ventilation quantity is adjusted through the baffle door 11 and releases heat, and the released heat is used as a heating medium for heating a refrigerant by each heat.
The water supply heat exchanger 12 is communicated with a water supply pipe 27 on one side and communicated with the economizer 16 on the other side, so that heat emitted by bypass flue gas flowing through the water supply heat exchanger 12 is used for heating water, the water supply enters the economizer 16 for continuous heating after being absorbed in the water supply heat exchanger 12, and therefore the waste heat of the bypass flue gas is used for heating the water supply, and the energy loss of the economizer 16 for heating the water supply is reduced.
The low-temperature primary air heat exchanger 15 is communicated with a cold primary air inlet pipe 20 at one side and is communicated with an intermediate primary air pipe 26 at the other side, the low-temperature primary air heat exchanger 15 is communicated with the high-temperature primary air heat exchanger 13 through the intermediate primary air pipe 26, and the high-temperature primary air heat exchanger 13 is communicated with a hearth 17, so that cold primary air firstly absorbs heat through the low-temperature primary air heat exchanger 15 to become intermediate primary air, then enters the high-temperature primary air heat exchanger 13 through the intermediate primary air pipe 26 to continuously absorb heat and heat up to become hot primary air, and finally heated hot primary air conveys heated pulverized coal and enters a coal mill 28; therefore, the waste heat of the bypass flue gas is utilized to heat the primary air, so that the energy loss of heating the primary air is reduced; moreover, the low-temperature primary air heat exchanger 15 and the high-temperature primary air heat exchanger 13 are adopted to exchange heat for the primary air for two times so as to ensure that the temperature of the primary air reaches the use requirement, and meanwhile, the high-temperature primary air heat exchanger 13 and the low-temperature primary air heat exchanger 15 both adopt shell-and-tube heat exchangers so as to ensure the heat exchange efficiency.
The circulating water inlet pipe 19 of the air heater and the circulating water outlet pipe 25 of the air heater are respectively communicated with the air heater 22; the temperature of the circulating water after heat exchange in the air heater 22 is reduced, the circulating water enters the air heater circulating water heat exchanger 14 through the air heater circulating water inlet pipe 19 and is heated by using the waste heat of the flue gas, and then the heating medium (namely the heated circulating water) is continuously provided for the air heater 22 through the air heater circulating water outlet pipe 25, so that the circulating water of the air heater is heated by using the waste heat of the flue gas, and the energy loss of heating the circulating water of the air heater is reduced;
the air heater 22 is mainly used for primarily heating cold secondary air, one side of the air heater 22 is communicated with a cold secondary air inlet pipe 23, the other side of the air heater 22 is communicated with a warm secondary air outlet pipe 9, the cold secondary air enters the heat exchanger 22 through the cold secondary air inlet pipe 23 and exchanges heat with heated circulating water, and the cold secondary air is changed into warm secondary air and flows into the warm secondary air outlet pipe 9; the warm secondary air outlet pipe 9 is divided into two paths, one path is communicated with the primary air chamber 5 of the three-chamber preheater 4, the other path is communicated with the secondary air chamber 6 of the three-chamber preheater 4, the outlet pipes of the primary air chamber 5 and the secondary air chamber 6 are converged to form the warm secondary air outlet pipe 8, and the warm secondary air outlet pipe 8 is also communicated with the hearth 17, so that the warm secondary air is respectively heated by the primary air chamber 5 and the secondary air chamber 6 and then converged into outlet hot secondary air which enters the hearth 17 through the hot secondary air outlet pipe 8, the hot secondary air is high-temperature air, and is matched with the primary air to stir and mix pulverized coal, thereby providing the air quantity required by pulverized coal combustion.
Finally, the bypass flue gas carries out ladder heating to feedwater, primary air, fan heater circulating water, realizes the make full use of bypass flue gas waste heat, and the bypass flue gas after exothermic then becomes bypass cold flue gas, and the cold flue gas of bypass gets into cold flue gas bypass 21 in, because cold flue gas bypass 21 also is linked together with flue gas follow-up treatment device 24, the cold flue gas of bypass finally gets into and carries out the subsequent processing in flue gas follow-up treatment device 24, realizes safe emission.
In addition, the coal economizer 16 and the hearth 17 are both positioned at the coal-fired boiler 1, so that the pulverized coal boiler system can normally operate.
The invention also discloses a heating method of the system for heating the primary air, the water supply and the circulating water by using the bypass flue gas, which comprises the following specific steps:
high-temperature hot flue gas generated by the coal-fired boiler 1 is divided into two paths, wherein one path enters a hot flue gas main path 3, and the other path enters a hot flue gas bypass 2; the hot flue gas entering the hot flue gas main path 3 flows through a flue gas chamber 7 of a trisection bin preheater 4 to release heat and is changed into main path cold flue gas, the released heat enters a secondary air chamber 6 and a primary air chamber 5, the main path cold flue gas flows through a cold flue gas main path 10 and then enters a flue gas post-processing device 24, and the flue gas post-processing device 24 performs post-processing;
the hot flue gas entering the hot flue gas bypass 2 is subjected to flux adjustment through a baffle door 11, and passes through a water supply heat exchanger 12, a high-temperature primary air heat exchanger 13, a fan heater circulating water heat exchanger 14 and a low-temperature primary air heat exchanger 15 in sequence to release heat, and then enters a cold flue gas bypass 21 to become bypass cold flue gas, and the bypass cold flue gas also enters a flue gas post-treatment device 24 to be subjected to post-treatment through the flue gas post-treatment device 24;
when hot flue gas of the hot flue gas bypass 2 flows through the water supply heat exchanger 12, water supply is introduced into the water supply heat exchanger 12 through the water supply pipe 27, the water supply absorbs heat and then enters the economizer 16, and the economizer 16 continues to heat the water supply;
when hot flue gas of the hot flue gas bypass 2 flows through the high-temperature primary air heat exchanger 13 and the low-temperature primary air heat exchanger 15, cold primary air firstly flows into the low-temperature primary air heat exchanger 15 through the cold primary air inlet pipe 20, the cold primary air absorbs heat in the low-temperature primary air heat exchanger 15 and then enters the intermediate primary air pipe 26 to become intermediate primary air, the intermediate primary air continuously flows into the high-temperature primary air heat exchanger 13 to further absorb heat and raise temperature to become hot primary air, and the hot primary air finally enters the coal mill 28;
when hot flue gas of the hot flue gas bypass 2 flows through the circulating water heat exchanger 14 of the air heater, cold secondary air enters the air heater 22 through the cold secondary air inlet pipe 23, the circulating water heat exchanger 14 of the air heater provides heat medium for the air heater 22 through the circulating water outlet pipe 25 of the air heater, the cold secondary air is heated by the heat medium in the air heater 22 to become hot secondary air, the heat medium after heat exchange continuously enters the circulating water heat exchanger 14 of the air heater through the circulating water outlet pipe 19 of the air heater to absorb heat, and therefore the heat medium is continuously provided for the air heater 22; meanwhile, the warm secondary air flows into the primary air chamber 5 and the secondary air chamber 6 respectively through the warm secondary air outlet pipe 9 to be reheated, and then is converged at the hot secondary outlet pipe 8 to form outlet hot secondary air, and the outlet hot secondary air is discharged into the hearth 17 through the hot secondary outlet pipe 8.
The system and the method disclosed by the invention utilize the waste heat of the bypass flue gas to heat the primary air, the water supply and the circulating water of the air heater at the same time, realize the step utilization of the waste heat of the flue gas, greatly improve the utilization of the waste heat of the flue gas, are more beneficial to environmental protection and energy conservation, simultaneously reduce the energy consumption for heating the primary air, the water supply and the circulating water of the air heater, and reduce the operation cost of the pulverized coal fired boiler system to a certain extent.
The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make variations, modifications, additions or substitutions within the technical scope of the present invention.
Claims (4)
1. Utilize bypass flue gas heating primary air, feedwater and circulating water's system, including three fens storehouse pre-heaters (4), its characterized in that: the air conditioner also comprises a water supply heat exchanger (12), a high-temperature primary air heat exchanger (13), a circulating water heat exchanger (14) of the air heater, a low-temperature primary air heat exchanger (15) and an air heater (22);
the three-bin preheater (4) is communicated with the coal-fired boiler (1), the SCR (18) is arranged at the position of the coal-fired boiler (1), and hot flue gas at the outlet of the SCR (18) is divided into a hot flue gas main path (3) and a hot flue gas bypass (2) at the inlet of the three-bin preheater (4);
a primary air chamber (5), a secondary air chamber (6) and a flue gas chamber (7) which are communicated with each other are arranged in the trisection bin preheater (4), a hot flue gas main path (3) is communicated with the flue gas chamber (7) of the trisection bin preheater (4), the flue gas chamber (7) is communicated with a cold flue gas main path (10), hot flue gas flowing through the hot flue gas main path (3) is changed into main path cold flue gas after heat release in the flue gas chamber (7), the main path cold flue gas enters the cold flue gas main path (10), and the cold flue gas main path (10) is communicated with a flue gas subsequent treatment device (24);
the hot flue gas bypass (2) is provided with a baffle door (11), the hot flue gas bypass (2) is communicated with a water supply heat exchanger (12), the baffle door (11) is positioned between the hot flue gas bypass (2) and the water supply heat exchanger (12), the high-temperature primary air heat exchanger (13), the air heater circulating water heat exchanger (14) and the low-temperature primary air heat exchanger (15) are communicated in sequence; the low-temperature primary air heat exchanger (15) is communicated with a cold flue gas bypass (21), hot flue gas flowing through the hot flue gas bypass (2) sequentially passes through the baffle door (11), the water supply heat exchanger (12), the high-temperature primary air heat exchanger (13), the air heater circulating water heat exchanger (14) and the low-temperature primary air heat exchanger (15) and releases heat, the hot flue gas passing through the hot flue gas bypass (3) is changed into bypass cold flue gas to enter the cold flue gas bypass (21), and the cold flue gas bypass (21) is also communicated with a flue gas subsequent treatment device (24);
the feed water heat exchanger (12) is communicated with a feed water pipe (27) at one side and communicated with an economizer (16) at the other side, and feed water enters the economizer (16) after being absorbed in the feed water heat exchanger (12); the low-temperature primary air heat exchanger (15) is communicated with a cold primary air inlet pipe (20) at one side and is communicated with a middle primary air pipe (26) at the other side, the low-temperature primary air heat exchanger (15) is communicated with the high-temperature primary air heat exchanger (13) through the middle primary air pipe (26), the high-temperature primary air heat exchanger (13) is communicated with a hearth (17), and cold primary air firstly absorbs heat through the low-temperature primary air heat exchanger (15), then enters the high-temperature primary air heat exchanger (13) to be heated and then enters a coal mill (28);
the circulating water inlet pipe (19) of the air heater and the circulating water outlet pipe (25) of the air heater are respectively communicated with the air heater (22); the hot air device (22) is communicated with a cold secondary air inlet pipe (23) at one side and a hot secondary air outlet pipe (9) at the other side, the hot secondary air outlet pipe (9) is divided into two paths, one path is communicated with the primary air chamber (5) of the three-chamber preheater (4), the other path is communicated with the secondary air chamber (6) of the three-chamber preheater (4), the cold secondary air is changed into the hot secondary air after heat exchange of the hot air device (22), and the hot secondary air is heated by the primary air chamber (5) and the secondary air chamber (6) respectively and then is converged into outlet hot secondary air; the outlet pipes of the primary air chamber (5) and the secondary air chamber (6) are converged to form a hot secondary air outlet pipe (8), and the hot secondary air outlet pipe (8) is also communicated with the hearth (17).
2. The system for heating primary air, feed water and circulating water by using bypass flue gas as claimed in claim 1, wherein: and the high-temperature primary air heat exchanger (13) and the low-temperature primary air heat exchanger (15) both adopt shell-and-tube heat exchangers.
3. The system for heating primary air, feed water and circulating water by using bypass flue gas as claimed in claim 1, wherein: the coal economizer (16) and the hearth (17) are both positioned at the position of the coal-fired boiler (1).
4. A heating method of a system for heating primary air, feed water and circulating water by using bypass flue gas as claimed in any one of claims 1 to 3, wherein: the heating method comprises the following specific steps:
high-temperature hot flue gas generated by the coal-fired boiler (1) is divided into two paths at an SCR (18) outlet, wherein one path enters a hot flue gas main path (3) and the other path enters a hot flue gas bypass path (2); hot flue gas entering a hot flue gas main path (3) flows through a flue gas chamber (7) of a trisection bin preheater (4) to release heat and is changed into main path cold flue gas, the released heat enters a secondary air chamber (6) and a primary air chamber (5), the main path cold flue gas flows through a cold flue gas main path (10) and then enters a flue gas post-processing device (24), and the flue gas post-processing device (24) performs post-processing;
the hot flue gas entering the hot flue gas bypass (2) is subjected to flux adjustment through a baffle door (11), passes through a water supply heat exchanger (12), a high-temperature primary air heat exchanger (13), a circulating water heat exchanger (14) of a fan heater and a low-temperature primary air heat exchanger (15) in sequence, releases heat, enters a cold flue gas bypass (21) after heat release to become bypass cold flue gas, and also enters a flue gas post-treatment device (24) to be subjected to post-treatment through the flue gas post-treatment device (24);
when hot flue gas of the hot flue gas bypass (2) flows through the water supply heat exchanger (12), water supply is introduced into the water supply heat exchanger (12) through the water supply pipe (27), the water supply absorbs heat and then enters the economizer (16), and the economizer (16) continues to heat the water supply;
when hot flue gas of the hot flue gas bypass (2) flows through the high-temperature primary air heat exchanger (13) and the low-temperature primary air heat exchanger (15), cold primary air firstly flows into the low-temperature primary air heat exchanger (15) through the cold primary air inlet pipe (20), the cold primary air absorbs heat in the low-temperature primary air heat exchanger (15) and then enters the middle primary air pipe (26) to become middle primary air, the middle primary air continuously flows into the high-temperature primary air heat exchanger (13) to further absorb heat and raise temperature to become warm primary air, and the warm primary air finally enters the coal mill (28);
when hot flue gas of the hot flue gas bypass (2) flows through the circulating water heat exchanger (14) of the air heater, cold secondary air enters the air heater (22) through the cold secondary air inlet pipe (23), the circulating water heat exchanger (14) of the air heater provides heat medium for the air heater (22) through the circulating water outlet pipe (25) of the air heater, the heat medium is heated circulating water, the cold secondary air is heated by the heat medium in the air heater (22) to become the hot secondary air, the heat medium after heat exchange continuously enters the circulating water heat exchanger (14) of the air heater through the circulating water outlet pipe (19) of the air heater to absorb heat, and therefore the heat medium is continuously provided for the air heater (22); meanwhile, the warm secondary air flows into the primary air chamber (5) and the secondary air chamber (6) through the warm secondary air outlet pipe (9) respectively to be reheated, and then is converged into outlet hot secondary air at the hot secondary outlet pipe (8) after being heated, and the outlet hot secondary air is discharged into the hearth (17) through the hot secondary outlet pipe (8).
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| CN201911142147.3A CN110779036A (en) | 2019-11-20 | 2019-11-20 | System and method for heating primary air, water supply and circulating water by using bypass flue gas |
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| CN201911142147.3A CN110779036A (en) | 2019-11-20 | 2019-11-20 | System and method for heating primary air, water supply and circulating water by using bypass flue gas |
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| CN111442256A (en) * | 2020-04-29 | 2020-07-24 | 北京慧峰仁和科技股份有限公司 | System and method for heating primary air, water supply and circulating water by using bypass flue gas |
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