CN117516243A - Deep recovery energy-saving system for waste heat of boiler flue gas - Google Patents
Deep recovery energy-saving system for waste heat of boiler flue gas Download PDFInfo
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- CN117516243A CN117516243A CN202311754762.6A CN202311754762A CN117516243A CN 117516243 A CN117516243 A CN 117516243A CN 202311754762 A CN202311754762 A CN 202311754762A CN 117516243 A CN117516243 A CN 117516243A
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- flue gas
- heat
- boiler
- air
- medium water
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 322
- 239000003546 flue gas Substances 0.000 title claims abstract description 322
- 239000002918 waste heat Substances 0.000 title claims abstract description 136
- 238000011084 recovery Methods 0.000 title claims abstract description 47
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 249
- 239000008236 heating water Substances 0.000 claims abstract description 119
- 238000005507 spraying Methods 0.000 claims abstract description 30
- 239000007921 spray Substances 0.000 claims abstract description 28
- 238000005192 partition Methods 0.000 claims description 47
- 238000010438 heat treatment Methods 0.000 claims description 37
- 238000009833 condensation Methods 0.000 claims description 7
- 230000005494 condensation Effects 0.000 claims description 7
- 230000001502 supplementing effect Effects 0.000 claims description 2
- 239000000779 smoke Substances 0.000 abstract description 20
- 238000007599 discharging Methods 0.000 abstract description 11
- 239000000446 fuel Substances 0.000 abstract description 10
- 238000002485 combustion reaction Methods 0.000 abstract description 8
- 238000001816 cooling Methods 0.000 abstract description 4
- 238000010586 diagram Methods 0.000 description 14
- 239000007789 gas Substances 0.000 description 13
- 206010022000 influenza Diseases 0.000 description 13
- 238000004064 recycling Methods 0.000 description 10
- 239000007791 liquid phase Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 7
- 239000012530 fluid Substances 0.000 description 6
- 238000004134 energy conservation Methods 0.000 description 3
- 238000010792 warming Methods 0.000 description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000006477 desulfuration reaction Methods 0.000 description 2
- 230000023556 desulfurization Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 238000003287 bathing Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
- F28D21/0001—Recuperative heat exchangers
- F28D21/0003—Recuperative heat exchangers the heat being recuperated from exhaust gases
-
- 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
-
- 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
- F23L15/04—Arrangements of recuperators
-
- 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
- F24D19/00—Details
-
- 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
- F24D2200/00—Heat sources or energy sources
- F24D2200/16—Waste heat
- F24D2200/18—Flue gas recuperation
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 a deep recovery energy-saving system for waste heat of boiler flue gas, wherein a spraying device and a first air heater are arranged on an air inlet pipeline; the smoke discharging flue is provided with a first smoke condenser and a second smoke condenser; the spray device is used for increasing the water content of air, a heat medium water circulation pipeline is arranged between the first air heater and the second flue gas condenser, heat medium water exchanges heat with flue gas in the second flue gas condenser, the heat medium water enters the first air heater to heat the air after being heated, water vapor entering the boiler along with the air is discharged out of the boiler along with flue gas after being heated by combustion, heat transfer and cooling, the temperature of the water vapor increased in the flue gas is increased, the dew point temperature of the flue gas is increased simultaneously, the flue gas discharged by the boiler enters the first flue gas condenser to exchange heat with heating water, waste heat is extracted from the flue gas, the flue gas waste heat is deeply recovered by the system, the boiler efficiency is improved, the fuel consumption is reduced, the structure is simple, the occupied area is small, the arrangement is flexible, and the spray device is suitable for various boiler pipelines.
Description
Technical Field
The invention relates to the field of energy conservation, environmental protection and flue gas waste heat recovery, in particular to a deep flue gas waste heat recovery energy-saving system for a boiler.
Background
The coal-fired boiler or the gas-fired boiler is a common boiler device for heating, bathing and other purposes, and common coal-fired boilers and gas-fired boilers comprise a hot water boiler, a steam boiler and the like.
The content of sulfide in the exhaust gas of the coal-fired boiler is high, the content of sulfide in the exhaust gas is reduced by adopting a wet desulfurization technology, and the content of water vapor in the exhaust gas of the coal-fired boiler is high after wet flue gas desulfurization; the gas boiler is affected by the chemical composition of the fuel, and the water vapor content in the discharged smoke is also very high. In addition, since the exhaust gas temperature of the coal-fired boiler or the gas-fired boiler is usually saturated temperature or higher than the dew point temperature of water vapor, the exhaust gas water vapor contains a large amount of water vapor latent heat, and according to analysis, the water vapor latent heat in the exhaust gas of the coal-fired boiler or the gas-fired boiler accounts for 10-11% of the heat value of fuel, and for the part of the exhaust gas waste heat, no effective recycling measures are available in the industry, so that huge energy waste is caused. Therefore, the deep recycling of the flue gas waste heat including the latent heat of water vapor of the coal-fired boiler or the gas-fired boiler has important significance for energy conservation and emission reduction.
In order to recycle the flue gas waste heat of the boiler, the prior art mainly realizes flue gas condensation, reduces the flue gas temperature and recovers part of condensed water in a flue gas and water heat exchange mode, and simultaneously recovers the sensible heat of the flue gas and the latent heat of water vapor, and as the backwater temperature of heating water is usually maintained at 40-55 ℃ and is limited by the backwater temperature of the heating water, the flue gas temperature of the boiler in the above measures cannot be reduced to be lower than the backwater temperature of the heating water, so that the flue gas waste heat cannot be deeply recovered. In order to reduce the exhaust gas temperature below 30 ℃, the existing treatment measures firstly adopt heat medium water as a carrier for circulation, and simultaneously set up a heat pump, absorb the waste heat of flue gas through the heat medium water, then send the waste heat into a heat pump unit to raise the temperature of heating water, and finally be used for central heating of a heat network. However, there are technical problems in practice with the treatment measures, such as (1) the heat pump requires high-grade heat source driving; (2) the heat pump has high manufacturing cost, large investment and long investment recovery period; (3) The heat pump requires extra space, is greatly limited by space, and is difficult to be used for modifying a pipeline system of a hot water boiler or a steam boiler. The existing treatment measure II adopts boiler water supply/waste heat water backwater to heat air firstly and then exchanges heat with flue gas, and the heated boiler water supply/waste heat water backwater is fed into a heat pump, so that compared with the conventional heat pump technology adopted by the treatment measure I, the driving heat source required by the treatment measure II is less, the heat pump investment is small, the waste heat of the same quantity is recovered, the heat load of the heat pump can be reduced by 20-40%, but the treatment measure II has the same problems, for example, the recovery capacity of the flue gas waste heat is limited because the specific heat of air is small, the air temperature rise is large and the heat carrying capacity of the air is small, and in addition, the heat pump and the driving heat source are also arranged in the treatment measure II, so that the same technical problems as the treatment measure I exist.
How to further optimize the boiler flue gas waste heat recycling system, not only can the deep recovery boiler flue gas waste heat be realized, but also the practical engineering implementation is realized, the method can be practically used for improving the existing boiler pipeline system, and meanwhile, the method can also improve the boiler efficiency, reduce the fuel consumption, simplify the system structure, reduce the investment and improve the return on investment, and is still the direction of the effort pursuit in the field.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides an optimized boiler flue gas waste heat deep recovery energy-saving system, which can deeply recover the boiler flue gas waste heat, improve the boiler efficiency and reduce the fuel consumption, has the advantages of simple structure, small equipment occupation area, flexible arrangement and strong engineering feasibility, and can be widely applied to the transformation and upgrading of the existing boiler pipeline system.
In order to achieve the above technical effects, according to one embodiment of the present invention, the technical scheme provided is as follows:
the boiler flue gas waste heat recovery energy-saving system comprises a boiler, wherein the boiler is provided with an air inlet pipeline and an exhaust flue,
a spraying device and a first air heater are sequentially arranged on an air inlet pipeline of the boiler;
A first flue gas condenser and a second flue gas condenser are sequentially arranged on a flue gas discharge flue of the boiler;
heating water returned from the heat supply pipe network enters a first flue gas condenser to exchange heat with a flue gas dividing wall, and flue gas waste heat is recovered;
the air is sprayed and humidified by the spraying device and then enters the first air heater to perform partition wall heat exchange and temperature rise, and finally enters the boiler;
a heat medium water circulation pipeline is arranged between the first air heater and the second flue gas condenser, heat medium water enters the second flue gas condenser to exchange heat with the low-temperature flue gas partition wall, waste heat of the flue gas is recovered and then enters the first air heater, heat exchange is carried out between the heat medium water and the sprayed and humidified air partition wall in the first air heater, so that the temperature of the air is increased, water is evaporated, and the heat medium water flowing out of the first air heater enters the second flue gas condenser again through the heat medium water circulation pipeline, so that heat medium water circulation is realized;
the flue gas is discharged from the boiler and is discharged after waste heat recovery.
The basic principle of the technical scheme is as follows:
in order to deeply recycle the waste heat of low-grade flue gas, a humidifying spraying device and a first air heater are arranged on an air inlet pipeline of a boiler; a first flue gas condenser and a second flue gas condenser are arranged on a flue gas discharge flue of the boiler; the spraying device is used for increasing the water content in the inlet air of the boiler, increasing the air heat capacity and improving the air heat carrying capacity; the heat medium water circulation pipeline is arranged between the first air heater and the second flue gas condenser, the heat medium water exchanges heat with low-temperature flue gas in the second flue gas condenser, low-grade flue gas waste heat takes the heat medium water as a carrier, and the low-grade flue gas waste heat is sent into the first air heater to heat the sprayed and humidified air and simultaneously evaporate liquid phase water into gas phase water, so that latent heat and sensible heat in the low-grade flue gas waste heat are transferred to the boiler air inlet (air), the boiler air inlet (air) carries the low-grade flue gas waste heat into the boiler, the fuel consumption is reduced after the air inlet temperature is increased, water vapor entering the boiler along with the air is discharged out of the boiler along with the flue gas after the combustion temperature is increased, the temperature of the water vapor increased in the flue gas is increased, the dew point temperature of the flue gas is also increased, the boiler is discharged into the first flue gas condenser and the heating heat exchange temperature is reduced, and finally, and the effect of recovering waste heat from the low-temperature flue gas and transferring the heating water is finally realized. The system can deeply recover the waste heat of the boiler flue gas, improves the boiler efficiency, reduces the fuel consumption, has the advantages of simple structure, small occupied area, flexible arrangement, strong engineering feasibility and the like, and can be widely applied to various boiler pipelines.
The boiler is a coal-fired boiler or a gas-fired boiler, more specifically a hot water boiler or a steam boiler.
When the boiler is a steam boiler, a heat supply network heater is also arranged, steam generated by the steam boiler enters the heat supply network heater to exchange heat with heating water flowing into the heat supply network heater, and the temperature of the heating water is increased.
The invention is applicable to various types of boiler smoke discharge flues, and the smoke discharge flues can be vertical smoke discharge flues or horizontal smoke discharge flues and can be original smoke discharge flues or modified smoke discharge flues of the boiler.
The invention is also not particularly limited to the air inlet pipeline of the boiler, and is applicable to various types of boiler air inlet pipelines, wherein the air inlet pipeline can be a vertical air inlet pipeline or a horizontal air inlet pipeline and can be an original air inlet pipeline or a modified air inlet pipeline of the boiler.
According to another embodiment of the invention, in order to prevent the sprayed and humidified air from still containing some liquid phase water after being heated by the first air heater, a second air heater is further arranged on an air inlet pipeline of the boiler, the sprayed and humidified air flows out of the first air heater and enters the second air heater, and partition wall heat exchange and temperature rise are carried out in the second air heater again, so that the sprayed and humidified air finally enters the boiler. By arranging the second air heater, the temperature of the inlet air (air) is further improved, unevaporated liquid-phase water in the inlet air of the boiler is eliminated, and the influence of the liquid-phase water on the combustion of the boiler is eliminated.
When the second air heater is arranged, optionally, heating water returned from the heat supply pipe network firstly enters the second air heater to be used as a heat source of the second air heater, exchanges heat with an air partition wall in the air inlet pipeline, improves the air temperature, and heating water flowing out of the second air heater enters the first flue gas condenser to exchange heat with the flue gas partition wall to recover flue gas waste heat, and is heated by the boiler or the heat supply network heater to become external hot water after being heated, so that heating water circulation is realized. In another alternative mode, part of the heating water returned from the heat supply pipe network enters the second air heater first to be used as a heat source of the second air heater, exchanges heat with an air partition wall in the air inlet pipeline, improves the air temperature, and the heating water flowing out of the second air heater and the rest of the heating water which does not enter the second air heater enter the first flue gas condenser to exchange heat with the flue gas partition wall together to recover flue gas waste heat.
When the second air heater is arranged, heating water heated by the boiler or the heat supply network heater is used as a heat source of the second air heater, the heating water firstly enters the first flue gas condenser to exchange heat with the flue gas partition wall, waste heat of the flue gas is recovered, then after the heating water is heated by the boiler or the heat supply network heater, all or part of the heating water enters the second air heater to be used as a heat source of the second air heater, sprayed and humidified air flows out of the first air heater and enters the second air heater, partition wall heat exchange is carried out again in the second air heater to heat, and finally the air enters the boiler.
Optionally, an economizer is further arranged on the smoke discharging flue of the boiler, and the economizer adopts a common structure in the prior art, and can be an original economizer of the boiler or an economizer added according to actual needs. And the flue gas is discharged from the boiler and then sequentially passes through the energy economizer, the first flue gas condenser and the second flue gas condenser for waste heat recovery, and then becomes discharged flue gas.
When the energy-saving device is arranged, heating water flows out from the first flue gas condenser and then enters the energy-saving device in whole or in part, and after the flue gas waste heat is recovered in the energy-saving device, the heating water enters the boiler or the heat supply network heater for heating. When the boiler is a hot water boiler, heating water flowing out of the first flue gas condenser completely enters the energy saver to recover flue gas waste heat, and then enters the boiler to be heated; the heating water flowing out of the first flue gas condenser can be partially sent into the energy saver to recover the waste heat of the flue gas and then sent into the boiler, and the other part of the heating water can be directly sent into the boiler without the energy saver. When the boiler is a steam boiler, the heating water flowing out of the first flue gas condenser can fully enter the energy saver to recover flue gas waste heat, and then the flue gas waste heat is sent into the heat supply network heater, and steam generated by the steam boiler enters the heat supply network heater to exchange heat with the heating water, so that the heating water is heated; the steam of the steam boiler becomes steam condensate after being cooled for cyclic utilization; the heating water flowing out of the first flue gas condenser can also partially enter the energy-saving device to recycle the flue gas waste heat and then enter the heat supply network heater, and the other part directly enters the heat supply network heater without passing through the energy-saving device.
Optionally, an air blower is arranged on an air inlet pipeline of the boiler, and heated air is fed into the boiler by the air blower.
Optionally, a heat medium water tank is arranged on the heat medium water circulation pipeline, the temperature of the heat medium water is reduced after the heat medium water flows out of the first air heater, the cooled heat medium water enters the heat medium water tank, and the heat medium water enters the second flue gas condenser for recycling the flue gas waste heat through the heat medium water circulation pipeline again, so that the heat medium water circulation is realized;
preferably, a heat medium water pump is arranged on the heat medium water circulation pipeline, and after the heat medium water flows out of the first air heater and enters the heat medium water tank, the heat medium water is sent into the second flue gas condenser again through the heat medium water circulation pipeline by the heat medium water pump to recover flue gas waste heat, so that the recycling of the flue gas waste heat and the circulation of the heat medium water are realized.
Preferably, the spraying device is connected with the heating medium water tank, the heating medium water is taken as spraying water from the heating medium water tank, the air is sprayed and humidified, the water content in the air is increased, the heat carrying capacity of the air is improved, the sprayed and humidified air enters the air heater for heating, and the absorption capacity of the air to the flue gas waste heat are enhanced.
Optionally, a spray water pump is arranged on a connecting pipeline of the spray device and the heating medium water tank, and the heating medium water is sent into the spray device by the spray water pump. In another alternative embodiment, the spraying device may also be connected to the outlet of the heat medium water pump of the heat medium water tank, and the heat medium water is delivered to the spraying device through the heat medium water pump after flowing out of the heat medium water tank.
After the boiler exhaust gas is subjected to waste heat recovery treatment, water vapor in the exhaust gas is cooled in a flue gas condenser and an energy saver to condense out flue gas condensate, and in order to achieve the technical effects of energy saving and emission reduction, the flue gas condensate is used as heat medium water supplementing water and is conveyed to a heat medium water tank through a pipeline.
Preferably, the flue gas condensate needs to be subjected to water treatment before or after entering the heat medium water tank;
further preferably, a drain valve is arranged on the heat medium water tank, and when the supply amount of the flue gas condensation water to the heat medium water tank exceeds the water amount required by the heat medium water circulation, part of the heat medium water in the heat medium water tank is discharged through the drain valve, so that the balance of the heat medium water circulation is maintained.
Preferably, after the heating water flows out of the first flue gas condenser, the heating water is conveyed by a water pump so as to reduce the design pressure of the first flue gas condenser.
The first flue gas condenser, the second flue gas condenser, the first air heater and the second air heater are partition wall type heat exchangers, and the partition wall type heat exchangers preferably adopt plate type heat exchangers or fin type tube heat exchangers. Compared with a direct contact type heat exchanger, such as a spray type heat exchanger (also called a spray tower), the dividing wall type heat exchanger has a plurality of advantages, for example, when the dividing wall type heat exchanger exchanges heat, cold and hot fluid is mutually isolated through a heat transfer wall surface, only heat exchange is carried out and the cold and hot fluid is not contacted with each other, the dividing wall type heat exchanger has small occupied space, simple structure and flexible arrangement, is not limited by sites, has no special requirements on the structure and the form of a flue in the use process, and can be suitable for horizontal flues, vertical flues and even various special-shaped flues; the direct contact type heat exchanger, such as a spray tower, needs to be vertically arranged in the use process, flue gas is from bottom to top, spray media are from top to bottom, cold and hot fluid realizes contact heat exchange in the convection process, in order to improve the heat exchange flow, enhance the heat exchange effect, the spray tower is generally higher and larger in space requirement, is not suitable for a horizontal flue or a special-shaped flue, is large in arrangement limitation and is limited in application scene, so that the invention simplifies the structural form of the system in order to improve the adaptability of the system, and adopts a dividing wall type heat exchanger.
The first flue gas condenser and the second flue gas condenser can be two partition wall type heat exchangers, and can also be a combined partition wall type heat exchanger, so that partition wall heat exchange of flue gas, heating water and heating medium water is realized in the same heat exchange plate pair.
When the first flue gas condenser and the second flue gas condenser are a combined dividing wall type heat exchanger, a flue gas flow channel is formed between a plate pair of the combined dividing wall type heat exchanger; the flue gas flows in from one side of the flue gas flow channel and flows out from the other side; the plate pairs are internally provided with heating water flow channels and heating medium water flow channels alternately; the heating water runner is provided with a heating water runner inlet and a heating water runner outlet; the heat medium water flow passage is provided with a heat medium water flow passage inlet and a heat medium water flow passage outlet.
The first air heater and the second air heater can be two partition wall type heat exchangers, and can also be a combined partition wall type heat exchanger, and partition wall heat exchange of air, heating water and heating medium water is realized in the same heat exchange plate pair.
When the first air heater and the second air heater are a combined dividing wall type heat exchanger, an air flow channel is formed between the plate pairs of the combined dividing wall type heat exchanger; air flows in from one side of the air flow channel and flows out from the other side; the plate pairs alternately form a heating medium water flow passage and a heating water flow passage inside; the heat medium water flow passage is provided with a heat medium water flow passage inlet and a heat medium water flow passage outlet; the heating water runner has a heating water runner inlet and a heating water runner outlet.
The invention has the beneficial effects that:
compared with the technical problems of low flue gas waste heat recovery utilization rate, high heat pump unit manufacturing cost, high operation and maintenance cost, complex structure, large occupied area, strong space and environment restriction and poor engineering adaptability in the prior art, the invention has the following advantages and technical effects:
(1) The heat pump unit is not needed, the structure is simple, the implementation difficulty is small, and the waste heat recovery energy efficiency is high.
(2) A humidifying spraying device and a first air heater are arranged on an air inlet pipeline of the boiler; a first flue gas condenser and a second flue gas condenser are arranged on a flue gas discharge flue of the boiler; the spraying device is used for increasing the water content in the inlet air of the boiler, increasing the air heat capacity and improving the air heat carrying capacity; the heat medium water circulation pipeline is arranged between the first air heater and the second flue gas condenser, the heat medium water exchanges heat with low-temperature flue gas in the second flue gas condenser, low-grade flue gas waste heat takes the heat medium water as a carrier, and the low-grade flue gas waste heat is sent into the first air heater to heat the sprayed and humidified air and evaporate liquid phase water into gas phase water, so that latent heat and sensible heat in the low-grade flue gas waste heat are transferred to the boiler air inlet (air), the boiler air inlet (air) carries the low-grade flue gas waste heat into the boiler, the fuel consumption is reduced after the air inlet temperature is increased, water vapor entering the boiler along with the air is discharged out of the boiler along with the flue gas after the combustion temperature is increased, the temperature of the water vapor increased in the flue gas is increased, the dew point temperature of the flue gas is also increased, the boiler is discharged into the first flue gas condenser to exchange heat with the heating water, and the temperature is reduced, and finally, the effect of recovering waste heat from the low-temperature flue gas and transferring the heating water is realized.
(3) The first flue gas condenser, the second flue gas condenser, the first air heater and/or the second air heater and the spraying device are arranged, so that deep recycling of flue gas waste heat is realized.
(4) The system can deeply recover the waste heat of the boiler flue gas, improve the boiler efficiency and reduce the fuel consumption.
(5) The invention adopts the dividing wall type heat exchanger, the dividing wall type heat exchanger has the characteristics of compact structure, small occupied area and flexible arrangement, is not limited by the structure and arrangement form of the boiler smoke exhaust flue and the air inlet pipeline in use, has strong engineering adaptability, and can well adapt to the reconstruction requirements of various new and old boiler systems. And the first flue gas condenser, the second flue gas condenser, the first air heater and the second air heater can also adopt a combined dividing wall type heat exchanger, so that the heat exchange requirements of different circulating pipelines can be realized in the same heat exchange plate pair, the equipment structure is further simplified, the transformation difficulty and the cost investment are reduced, and the occupied area and the space are saved.
Drawings
Fig. 1: the embodiment 1 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 2: the embodiment 2 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 3: the embodiment 3 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 4: the embodiment 4 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 5: the embodiment 5 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 6: the embodiment 6 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 7: embodiment 7 of the invention provides a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 8: the embodiment 8 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 9: the embodiment 9 of the invention provides a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 10: the embodiment 10 of the invention provides a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 11: the embodiment 11 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 12: the embodiment 12 of the invention shows a schematic diagram of a boiler flue gas waste heat recovery energy-saving system
Fig. 13: the first flue gas condenser and the second flue gas condenser are plate structure schematic diagrams when the combined dividing wall type heat exchanger is adopted
Fig. 14: the first air heater and the second air heater are plate structure schematic diagrams when the combined dividing wall type heat exchanger
Reference numerals illustrate:
the boiler comprises a boiler 1, a spraying device 2, a first air heater 3, a first flue gas condenser 4 and a second flue gas condenser 5;
an air blower 6, a heating medium water tank 7, a heating medium water pump 8, a spray water pump 9, a water treatment device 10, a drain valve 11, a water pump 12, a second air heater, 13 and a heating network heater 14;
heating water a; air b; heating medium water c; flue gas d; flue gas condensation water e; an economizer f; steam g.
Detailed Description
The invention will now be further described with reference to the accompanying drawings, but the following embodiments do not limit the invention.
Example 1
Fig. 1 shows a boiler flue gas waste heat recovery energy-saving system provided by the invention, which comprises a boiler 1, wherein the boiler 1 is a hot water boiler, the boiler 1 is provided with an air inlet pipeline and an exhaust flue,
a spraying device 2 and a first air heater 3 are sequentially arranged on an air inlet pipeline of the boiler;
a first flue gas condenser 4 and a second flue gas condenser 5 are sequentially arranged on a flue gas discharge flue of the boiler;
the heating water a returned from the heat supply pipe network enters the first flue gas condenser 4 to recover flue gas waste heat, and the heated heating water a is heated by the boiler 1 to become external hot water, so that heating water circulation is realized;
The air b is sprayed and humidified by the spraying device 2 and then enters the first air heater 3 to be heated, and then is fed into the boiler 1;
a heat medium water circulation pipeline is arranged between the first air heater 3 and the second flue gas condenser 5, heat medium water c is recycled in the second flue gas condenser 5 and then enters the first air heater 3, the recycled flue gas heat is used for heating air b and evaporating water, and the cooled heat medium water c enters the second flue gas condenser 5 again through the heat medium water circulation pipeline to realize heat medium water c circulation;
the flue gas d is discharged from the boiler 1 and is discharged after waste heat recovery.
According to the invention, the first flue gas condenser 4 is arranged, the flue gas waste heat is recovered to improve the temperature of heating water a, and the heating water a is heated by the boiler 1 to become external hot water, so that heating water circulation is realized, the fuel consumption is reduced by recovering the flue gas waste heat, and the energy is saved; (2) The flue gas waste heat is recovered through the heat medium water c by utilizing a heat medium water circulation pipeline between the first air heater 3 and the second flue gas condenser 5, and the recovered flue gas heat is transferred to the air b for air heating, so that the air inlet temperature of the boiler is improved, and the combustion performance of the boiler is improved; (3) The spraying device 2 sprays and humidifies the air b, so that the water content in the air fed by the boiler is increased, the heat capacity of the air is increased, the heat carrying capacity of the air is improved, and the absorption capacity of the air to the residual heat of the flue gas are further improved.
The invention has no special limitation on the smoke discharging flue of the boiler, is applicable to various types of boiler smoke discharging flues, the smoke discharging flue can be a vertical smoke discharging flue or a horizontal smoke discharging flue, can be an original smoke discharging flue of the boiler or a modified smoke discharging flue,
the invention is also not particularly limited to the air inlet pipeline of the boiler, and is applicable to various types of boiler air inlet pipelines, wherein the air inlet pipeline can be a vertical air inlet pipeline or a horizontal air inlet pipeline and can be an original air inlet pipeline or a modified air inlet pipeline of the boiler.
Preferably, the spraying device 2 and the first air heater 3 are arranged on an original air inlet pipeline of the boiler 1; the first flue gas condenser 4 and the second flue gas condenser 5 are arranged on an original smoke discharging flue of the boiler.
Optionally, an air blower 6 is arranged on an air inlet pipeline of the boiler 1, and heated air is fed into the boiler 1 by the air blower 6.
Optionally, a heat medium water tank 7 is arranged on the heat medium water circulation pipeline, the temperature of the heat medium water c is reduced after the heat medium water c flows out of the first air heater 3, the cooled heat medium water c enters the heat medium water tank 7, and then the heat medium water c is circulated into the second flue gas condenser 5 through the heat medium water circulation pipeline to recover flue gas waste heat, so that heat medium water circulation is realized;
Preferably, a heat medium water pump 8 is arranged on the heat medium water circulation pipeline, the heat medium water c flows out of the first air heater 3 and enters the heat medium water tank 7, and then the heat medium water is sent into the second flue gas condenser 5 by the heat medium water pump 8 through the heat medium water circulation pipeline, so that the recycling of the flue gas waste heat and the circulation of the heat medium water are realized.
Preferably, the spraying device 2 is connected with the heating medium water tank 7, and the heating medium water is taken from the heating medium water tank 7 as spraying water to spray and humidify the air b. Optionally, a spray water pump 9 is arranged on a connecting pipeline between the spray device 2 and the heat medium water tank 7, and the heat medium water c is conveyed to the spray device 2 through the spray water pump 9.
In another alternative embodiment, the spraying device 2 is directly connected with the outlet of the heat medium water pump 8, and the heat medium water pump 8 takes water from the heat medium water tank 7 and then conveys the water to the spraying device 2 to realize the spraying humidification of air.
After the boiler flue gas is subjected to waste heat recovery treatment, water vapor in the flue gas is cooled and condensed in the flue gas to obtain flue gas condensate e, and in order to realize energy conservation and emission reduction, the flue gas condensate e is used as heat medium water to be fed to the heat medium water tank 7 through a pipeline.
Optionally, the flue gas condensate e may require water treatment before or after entering the heating medium tank 7. Preferably, a water treatment device 10 is arranged on a conveying pipeline of the flue gas condensation water e, and the flue gas condensation water e enters the heat medium water tank 7 after being treated by the water treatment device 10; further preferably, the water discharge valve 11 is arranged on the heat medium water tank 7, and when the supply amount of the flue gas condensation water e to the heat medium water tank 7 exceeds the water amount required by the heat medium water circulation, part of the heat medium water in the heat medium water tank is discharged through the water discharge valve 11, so that the balance of the heat medium water circulation is maintained.
Preferably, the heating water a is delivered through the water pump 12 after flowing out of the first flue gas condenser 4 to reduce the design pressure of the first flue gas condenser 4.
The first flue gas condenser 4, the second flue gas condenser 5 and the first air heater 3 are dividing wall type heat exchangers, and the dividing wall type heat exchangers are preferably plate type heat exchangers or fin tube type heat exchangers. Compared with a direct contact type heat exchanger, such as a spray type heat exchanger (also called a spray tower), the dividing wall type heat exchanger has a plurality of advantages, for example, when the dividing wall type heat exchanger exchanges heat, cold and hot fluid is mutually isolated through a heat transfer wall surface, only heat exchange is carried out and the cold and hot fluid is not contacted with each other, the dividing wall type heat exchanger has small occupied space, simple structure and flexible arrangement, is not limited by sites, has no special requirements on the structure and the form of a flue in the use process, and can be suitable for horizontal flues, vertical flues and even various special-shaped flues; the direct contact type heat exchanger, such as a spray tower, needs to be vertically arranged in the use process, flue gas is from bottom to top, spray media are from top to bottom, cold and hot fluid realizes contact heat exchange in the convection process, in order to improve the heat exchange flow, enhance the heat exchange effect, the spray tower is generally higher and larger in space requirement, is not suitable for a horizontal flue or a special-shaped flue, is large in arrangement limitation and is limited in application scene, so that the invention simplifies the structural form of the system in order to improve the adaptability of the system, and adopts a dividing wall type heat exchanger.
The first flue gas condenser 4 and the second flue gas condenser 5 can be two partition wall type heat exchangers, and can also be a combined partition wall type heat exchanger, so that partition wall heat exchange of flue gas, heating water and heating medium water is realized in the same heat exchange plate pair.
When the first flue gas condenser 4 and the second flue gas condenser 5 are a combined dividing wall type heat exchanger, the plate structure of the combined dividing wall type heat exchanger is shown in fig. 13; a flue gas flow channel is formed between the plate pairs of the combined dividing wall type heat exchanger; the flue gas flows in from one side of the flue gas flow channel and flows out from the other side; the plate pairs are internally provided with heating water flow channels and heating medium water flow channels alternately; the heating water runner is provided with a heating water runner inlet and a heating water runner outlet; the heat medium water flow passage is provided with a heat medium water flow passage inlet and a heat medium water flow passage outlet.
Example 2
Fig. 2 shows another energy-saving system for recovering flue gas waste heat of a boiler according to the present invention, which is different from embodiment 1 in that a second air heater 13 is added to the air inlet duct.
In order to prevent the air b sprayed and humidified by the spraying device 2 from containing liquid phase water after being heated by the first air heater 3 and further affecting the combustion performance of the boiler, the invention adds a second air heater 13 on the air inlet pipeline of the boiler 1. The sprayed and humidified air flows out from the first air heater 3 and enters the second air heater 13, and the air is subjected to partition wall heat exchange again in the second air heater 13 to raise the temperature, and finally enters the boiler 1. By providing the second air heater 13, the temperature of the inlet air (air b) is further raised, the unevaporated liquid phase water in the inlet air of the boiler is eliminated, and the influence of the liquid phase water on the combustion performance of the boiler is eliminated.
The second air heater 13 uses the heating water a as a heat source, the heating water a returned from the heat supply pipe network firstly enters the second air heater 13 to exchange heat with the air b from the air inlet pipe in a partition wall manner, the air temperature is raised, then the cooled heating water a flowing out of the second air heater 13 enters the first flue gas condenser 4 to exchange heat with the flue gas partition wall, the temperature of the recovered flue gas waste heat is raised, and the heated heating water a becomes external hot water after being heated by the boiler, thereby realizing heating water circulation. In another alternative mode, the heating water a returned from the heat supply pipe network firstly enters the second air heater 13 partially and is used as a heat source of the second air heater 13 to exchange heat with an air partition wall, so that the air temperature is raised, the heating water flowing out of the second air heater 13 and the rest of heating water which does not enter the second air heater enter the first flue gas condenser 4 to exchange heat with the flue gas partition wall, the flue gas waste heat is recovered, and the heating water is heated by a boiler or a heat supply network heater to become external hot water, so that the heating water circulation is realized.
Other structures in embodiment 2 are the same as those in embodiment 1.
The first air heater 3 and the second air heater 13 can be two partition wall type heat exchangers, or can be a combined partition wall type heat exchanger, and partition wall heat exchange of air, heating water and heating medium water is realized in the same heat exchange plate pair. The dividing wall type heat exchanger is preferably a plate type heat exchanger or a fin tube type heat exchanger.
When the first air heater 3 and the second air heater 13 are a combined dividing wall type heat exchanger, the plate structure of the combined dividing wall type heat exchanger is shown in fig. 14; an air flow channel is formed between the plate pairs of the combined dividing wall type heat exchanger; air flows in from one side of the air flow channel and flows out from the other side; the plate pairs alternately form a heating medium water flow passage and a heating water flow passage inside; the heat medium water flow passage is provided with a heat medium water flow passage inlet and a heat medium water flow passage outlet; the heating water runner has a heating water runner inlet and a heating water runner outlet.
Example 3
Fig. 3 shows another energy-saving system for recovering flue gas waste heat of a boiler, which is different from embodiment 1 in that an economizer f is further arranged on the flue of the boiler 1, and the economizer f adopts a common structure in the prior art, and can be an original economizer of the boiler or an economizer added according to actual needs. The flue gas is discharged from the boiler and then sequentially passes through the economizer f, the first flue gas condenser 4 and the second flue gas condenser 5 for waste heat recovery, and then becomes discharged flue gas.
When the economizer f is provided, the heating water a flows out of the first flue gas condenser 4 and then enters the economizer f in whole or in part, and after the flue gas waste heat is recovered in the economizer f, the heating water a is heated by the boiler to become external hot water. Fig. 3 shows a case where part of the heating water a flowing out of the first flue gas condenser 4 is sent to the economizer f to be heated and then sent to the boiler to be heated, and the other part is directly sent to the hot water boiler to be heated without passing through the economizer f.
Example 4
Fig. 4 shows another energy-saving system for recovering flue gas waste heat of a boiler, which is different from embodiment 2 in that an economizer f is further arranged on a flue for discharging flue gas of the boiler 1, and flue gas is discharged from the boiler and then subjected to waste heat recovery through the economizer f, the first flue gas condenser 4 and the second flue gas condenser 5 in sequence, and then becomes discharged flue gas.
Heating water a firstly enters the second air heater 13 to exchange heat with air b from the air inlet pipeline, the air temperature is raised, then the cooled heating water a flowing out of the second air heater 13 enters the first flue gas condenser 4 to exchange heat with flue gas, the temperature of the recovered flue gas waste heat is raised, the heating water a flows out of the first flue gas condenser 4 and then enters the energy saver f in whole or in part, and after the flue gas waste heat is recovered in the energy saver f, the heating water a is heated by a boiler to be external hot water.
In another alternative mode, the heating water a returned from the heat supply pipe network firstly enters the second air heater 13 partially and is used as a heat source of the second air heater 13 to exchange heat with an air partition wall, so that the air temperature is raised, the heating water flowing out of the second air heater 13 and the rest of heating water which does not enter the second air heater enter the first flue gas condenser 4 to exchange heat with the flue gas partition wall, the flue gas waste heat is recovered, and the heating water is heated by a boiler or a heat supply network heater to become external hot water, so that the heating water circulation is realized.
Fig. 4 shows a case where part of the heating water a flowing out of the first flue gas condenser 4 is sent to the economizer f to be heated and then sent to the boiler to be heated, and the other part is directly sent to the hot water boiler to be heated without passing through the economizer f.
Example 5
Fig. 5 shows another boiler flue gas waste heat recovery energy saving system of the present invention, which differs from embodiment 1 in that the boiler 1 is a steam boiler, and the boiler flue gas waste heat recovery energy saving system is further provided with a heat supply network heater 14;
the heating water a enters the first flue gas condenser 4 to exchange heat with flue gas to recover flue gas waste heat, the heating water a flowing out of the first flue gas condenser 4 is sent to the heat supply network heater 14, and steam g generated by the boiler 1 enters the heat supply network heater 14 to exchange heat with the heating water a in the heat supply network heater 14; the heating water a becomes external hot water after heating, and the steam g of the boiler 1 becomes steam condensate after cooling down for recycling.
Example 6
Fig. 6 shows another energy-saving system for recovering flue gas waste heat of a boiler, which is different from embodiment 5 in that a second air heater 13 is added on an air inlet pipeline of the boiler 1 in order to prevent the air b sprayed and humidified by the spraying device 2 from containing some liquid phase water after being heated by the first air heater 3, thereby affecting the combustion performance of the boiler.
The second air heater 13 takes heating water a as a heat source, all the heating water a returned from a heat supply pipe network firstly enters the second air heater 13 to exchange heat with air b from an air inlet pipeline, the temperature of the air is raised, then the cooled heating water a flowing out of the second air heater 13 enters the first flue gas condenser 4 to exchange heat with flue gas, the temperature of the recovered flue gas waste heat is raised, the heated heating water a is sent into the heat supply network heater 14, and steam g generated by the boiler 1 enters the heat supply network heater 14 to exchange heat with the heating water a in the heat supply network heater 14; the heating water a becomes external hot water after heating, and the steam g of the boiler 1 becomes steam condensate after cooling down for recycling. Alternatively, the heating water a returned from the heat supply pipe network enters the second air heater 13 as a heat source of the second air heater 13, exchanges heat with the air partition wall, raises the air temperature, and enters the first flue gas condenser 4 together with the rest of heating water which does not enter the second air heater, exchanges heat with the flue gas partition wall, and recovers the flue gas waste heat.
Example 7
Fig. 7 shows another energy-saving system for recovering flue gas waste heat of a boiler, which is different from embodiment 5 in that an economizer f is further arranged on a flue gas discharge flue of the boiler 1, and flue gas is discharged from the boiler and then subjected to waste heat recovery through the economizer f, the first flue gas condenser 4 and the second flue gas condenser 5 in sequence, and then becomes discharged flue gas.
When the energy-saving device f is arranged, heating water a flows out of the first flue gas condenser 4 and then enters the energy-saving device f in whole or in part, after flue gas waste heat is recovered in the energy-saving device f, the heating water a flowing out of the energy-saving device f is sent into the heat supply network heater 14, and steam g generated by the boiler 1 enters the heat supply network heater 14 to exchange heat with the heating water a in the heat supply network heater 14; the heating water a becomes external hot water after heating, and the steam g of the boiler 1 becomes steam condensate after cooling down for recycling.
Example 8
Fig. 8 shows another energy-saving system for recovering flue gas waste heat of a boiler, which is different from embodiment 6 in that an economizer f is further arranged on the flue of the boiler 1, and the rest of the structure is the same as embodiment 6.
Example 9
Fig. 9 shows another boiler flue gas waste heat recovery and energy saving system of the present invention, which is different from embodiment 2 in the flow pattern of heating water a in the second air heater 13.
Heating water a returned from a heat supply pipe network firstly enters a first flue gas condenser 4 to exchange heat with a flue gas partition wall, waste heat of flue gas is recovered, then the flue gas is heated and warmed by a boiler 1, then all or part of the flue gas enters a second air heater 13 to serve as a heat source of the second air heater 13, sprayed and humidified air b flows out of the first air heater 3 and enters the second air heater 13, partition wall heat exchange and warming are carried out in the second air heater 13 again, and finally the flue gas enters the boiler 1.
Example 10
Fig. 10 shows another boiler flue gas waste heat recovery and energy saving system of the present invention, which is different from embodiment 4 in the flow pattern of heating water a in the second air heater 13.
Heating water a returned from a heat supply pipe network firstly enters a first flue gas condenser 4 to exchange heat with a flue gas partition wall, the temperature of recovered flue gas waste heat is increased, all or part of the heating water a flows out of the first flue gas condenser 4 and then enters an energy economizer f, after the flue gas waste heat is recovered in the energy economizer f, the heating water a is heated and raised through a boiler 1, all or part of the heating water a enters a second air heater 13 to serve as a heat source of the second air heater 13, sprayed and humidified air b flows out of the first air heater 3 and then enters the second air heater 13, partition wall heat exchange and raised in the second air heater 13 are performed again, and finally the heating water a enters the boiler 1.
Example 11
Fig. 11 shows another boiler flue gas waste heat recovery and energy saving system of the present invention, which is different from embodiment 6 in the flow pattern of heating water a in the second air heater 13.
Heating water a returned from a heat supply pipe network firstly enters a first flue gas condenser 4 to exchange heat with a flue gas partition wall, waste heat of the flue gas is recovered, then the flue gas is heated and warmed by a heat supply network heater 14, then all or part of the flue gas enters a second air heater 13 to serve as a heat source of the second air heater 13, sprayed and humidified air b flows out of the first air heater 3 and enters the second air heater 13, partition wall heat exchange and warming are carried out in the second air heater 13 again, and finally the flue gas enters the boiler 1.
Example 12
Fig. 12 shows another boiler flue gas waste heat recovery and energy saving system of the present invention, which is different from embodiment 8 in the way of circulating heating water a in the second air heater 13.
Heating water a returned from a heat supply pipe network firstly enters a first flue gas condenser 4 to exchange heat with a flue gas partition wall to recover flue gas waste heat, then enters an energy economizer f in whole or in part, after the flue gas waste heat is recovered in the energy economizer f, the flue gas waste heat is heated and warmed by a heat supply network heater 14, then enters a second air heater 13 in whole or in part to serve as a heat source of the second air heater 13, sprayed and humidified air b flows out of the first air heater 3 and enters the second air heater 13, partition wall heat exchange and warming are carried out again in the second air heater 13, and finally the air enters the boiler 1.
While the invention has been described in detail in the foregoing description with reference to specific examples, which are provided to illustrate the principles and embodiments of the invention, the examples are provided to assist in understanding the invention and are not to be construed as limiting the invention.
Claims (21)
1. The deep recovery energy-saving system for the flue gas waste heat of the boiler comprises the boiler, wherein the boiler is provided with an air inlet pipeline and an exhaust flue,
A spraying device and a first air heater are sequentially arranged on an air inlet pipeline of the boiler;
a first flue gas condenser and a second flue gas condenser are sequentially arranged on a flue gas discharge flue of the boiler;
heating water returned from the heat supply pipe network enters a first flue gas condenser to exchange heat with a flue gas dividing wall, and flue gas waste heat is recovered;
the air is sprayed and humidified by the spraying device and then enters the first air heater to perform partition wall heat exchange and temperature rise, and finally enters the boiler;
a heat medium water circulation pipeline is arranged between the first air heater and the second flue gas condenser, heat of the heat medium water enters the second flue gas condenser to exchange heat with the flue gas partition wall, after the waste heat of the flue gas is recovered, the heat medium water enters the first air heater to exchange heat with the sprayed and humidified air partition wall in the first air heater, so that the temperature of the air is raised, water is evaporated, and the heat medium water flowing out of the first air heater is sent into the second flue gas condenser again through the heat medium water circulation pipeline to realize heat medium water circulation;
the flue gas is discharged from the boiler and is discharged after waste heat recovery.
2. The boiler flue gas waste heat recovery energy saving system of claim 1, wherein the boiler is a hot water boiler or a steam boiler; when the boiler is a steam boiler, a heat supply network heater is arranged, steam generated by the steam boiler enters the heat supply network heater to exchange heat with heating water flowing into the heat supply network heater, and the temperature of the heating water is increased.
3. The energy-saving system for recovering flue gas waste heat of a boiler according to claim 2, wherein the air inlet pipeline is further provided with a second air heater, the sprayed and humidified air flows out of the first air heater and then enters the second air heater, and the partition wall heat exchange and the temperature rise are carried out in the second air heater again, so that the air finally enters the boiler.
4. The energy saving system for recovering waste heat of flue gas of boiler as claimed in claim 3, wherein the heating water returned from the heat supply pipe network is fed into the second air heater in whole or in part as a heat source of the second air heater to exchange heat with the air partition wall in the air inlet pipe, thereby raising the air temperature.
5. The energy-saving system for recovering waste heat of flue gas of boiler as claimed in claim 3, wherein the heating water heated by the boiler or the heating network heater is wholly or partially fed into the second air heater as the heat source of the second air heater, the sprayed and humidified air flows out of the first air heater and then fed into the second air heater, and the air is subjected to heat exchange of partition walls again in the second air heater to be heated, and finally fed into the boiler.
6. The energy-saving system for recovering waste heat of flue gas of a boiler according to claim 2, wherein an energy economizer is further arranged on the flue gas discharge flue, and flue gas is discharged after being discharged from the boiler and is subjected to waste heat recovery through the energy economizer, the first flue gas condenser and the second flue gas condenser in sequence.
7. The energy saving system for recovering flue gas waste heat of boiler according to claim 6, wherein the heating water flows out from the first flue gas condenser and then enters the energy saving device in whole or in part, and after the flue gas waste heat is recovered in the energy saving device, the heating water enters the boiler or the heating network heater for heating.
8. The energy saving system for recovering flue gas waste heat of boiler according to claim 2, wherein an air blower is arranged on the air inlet pipe of the boiler, and air is fed into the boiler by the air blower.
9. The energy-saving system for recovering waste heat of boiler flue gas according to claim 2, wherein the heat medium water circulating pipeline is provided with a heat medium water tank, and the heat medium water flows out of the first air heater, enters the heat medium water tank, and is sent into the second flue gas condenser again through the heat medium water circulating pipeline to realize heat medium water circulation.
10. The energy-saving system for recovering waste heat of boiler flue gas according to claim 9, wherein the heat medium water circulating pipeline is provided with a heat medium water pump, and after the heat medium water enters the heat medium water tank, the heat medium water pump is adopted to send the heat medium water into the second flue gas condenser again through the heat medium water circulating pipeline.
11. The energy-saving system for recovering waste heat of flue gas of a boiler according to claim 10, wherein the spraying device is connected with the heating medium water tank, and the heating medium water is taken from the heating medium water tank as spraying water to spray and humidify air.
12. The energy-saving system for recovering waste heat of flue gas of a boiler according to claim 11, wherein a spray water pump is arranged on a connecting pipeline of the spray device and the heat medium water tank, and the heat medium water is sent into the spray device by adopting the spray water pump.
13. The energy saving system for recovering waste heat of boiler flue gas according to claim 11, wherein the spraying device is connected to an outlet of the heat medium water pump, and the heat medium water is delivered to the spraying device by the heat medium water pump after flowing out from the heat medium water tank.
14. The energy-saving system for recovering waste heat of flue gas of claim 9, wherein the water vapor contained in the flue gas is cooled and condensed to form flue gas condensate after waste heat recovery, and the flue gas condensate is used as the hot medium water for supplementing water and is conveyed to the hot medium water tank through a pipeline.
15. The boiler flue gas waste heat recovery energy saving system of claim 14, wherein flue gas condensate is treated with water before or after delivery to the heat medium tank.
16. The energy saving system for recovering waste heat of flue gas of claim 14, wherein a drain valve is provided on the heat medium water tank, and when the supply amount of flue gas condensation water to the heat medium water tank exceeds the water amount required by the heat medium water circulation, part of the heat medium water in the heat medium water tank is discharged through the drain valve to maintain the balance of the heat medium water circulation.
17. The energy saving system for recovering waste heat of flue gas from a boiler according to claim 1, wherein the heating water flowing out from the first flue gas condenser is transported by a water pump.
18. The energy saving system for recovering waste heat of flue gas from a boiler according to claim 1, wherein the first flue gas condenser and the second flue gas condenser are two dividing wall type heat exchangers or one combined dividing wall type heat exchanger.
19. The boiler flue gas waste heat recovery energy saving system of claim 1, wherein the first air heater is a dividing wall heat exchanger.
20. The energy-saving system for recovering waste heat of flue gas of boiler according to claim 3, wherein the first air heater and the second air heater are two dividing wall type heat exchangers or one combined dividing wall type heat exchanger.
21. The boiler flue gas waste heat recovery energy saving system of any one of claims 18 to 20, wherein the dividing wall heat exchanger is a plate heat exchanger or a fin tube heat exchanger.
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| CN202311754762.6A CN117516243A (en) | 2023-12-18 | 2023-12-18 | Deep recovery energy-saving system for waste heat of boiler flue gas |
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| CN202311754762.6A CN117516243A (en) | 2023-12-18 | 2023-12-18 | Deep recovery energy-saving system for waste heat of boiler flue gas |
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