CN117663103A - Waste heat recovery system of thermal power plant - Google Patents
Waste heat recovery system of thermal power plant Download PDFInfo
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- CN117663103A CN117663103A CN202311560648.XA CN202311560648A CN117663103A CN 117663103 A CN117663103 A CN 117663103A CN 202311560648 A CN202311560648 A CN 202311560648A CN 117663103 A CN117663103 A CN 117663103A
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- 238000011084 recovery Methods 0.000 title claims abstract description 36
- 239000002918 waste heat Substances 0.000 title claims abstract description 29
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 138
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 123
- 239000003546 flue gas Substances 0.000 claims abstract description 121
- 239000007789 gas Substances 0.000 claims abstract description 43
- 230000001502 supplementing effect Effects 0.000 claims abstract description 25
- 238000009833 condensation Methods 0.000 claims abstract description 13
- 230000005494 condensation Effects 0.000 claims abstract description 13
- 238000010438 heat treatment Methods 0.000 claims abstract description 13
- 238000000034 method Methods 0.000 claims abstract description 7
- 239000002699 waste material Substances 0.000 claims abstract description 5
- 239000003507 refrigerant Substances 0.000 claims description 10
- 239000007788 liquid Substances 0.000 claims description 9
- 230000006835 compression Effects 0.000 claims description 6
- 238000007906 compression Methods 0.000 claims description 6
- 230000003020 moisturizing effect Effects 0.000 claims description 6
- 238000005260 corrosion Methods 0.000 claims description 5
- 230000007797 corrosion Effects 0.000 claims description 5
- 229910000831 Steel Inorganic materials 0.000 claims description 4
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- 239000010959 steel Substances 0.000 claims description 4
- 238000010521 absorption reaction Methods 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 239000011152 fibreglass Substances 0.000 claims description 2
- 239000010908 plant waste Substances 0.000 claims 3
- 239000000126 substance Substances 0.000 abstract description 4
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- 230000008016 vaporization Effects 0.000 abstract description 4
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 239000013589 supplement Substances 0.000 abstract description 3
- 239000003570 air Substances 0.000 description 6
- 239000002253 acid Substances 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000000428 dust Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 238000010248 power generation Methods 0.000 description 4
- 239000003344 environmental pollutant Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 2
- 239000012080 ambient air Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 239000011555 saturated liquid Substances 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 1
- 108700041286 delta Proteins 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
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Abstract
The invention discloses a waste heat recovery system of a thermal power plant, which comprises a power station boiler, a steam turbine, a waste steam waste heat recovery device, a gas-gas heat exchanger, a wet deacidification tower, a flue gas condenser, an induced draft fan, a chimney and a water supplementing mechanism, wherein the steam turbine is connected with the power station boiler; the water supplementing mechanism is used for supplementing the condensate water obtained by the exhaust steam waste heat recovery device into the power station boiler and supplementing the water obtained by condensation in the flue gas condenser into the wet deacidification tower. The beneficial effects of the invention are as follows: the latent heat of vaporization of the vapor in the flue gas exhausted by the power station boiler is fully recovered and then used for heating the condensed water, so that the heating vapor amount consumed by the deaerator is reduced, and meanwhile, the condensed water is recovered as the water supplement of the wet deacidification tower after chemical adding treatment, so that the consumption of water resources in the deacidification process is reduced; meanwhile, heat of exhaust steam generated by the steam turbine is transferred to combustion-supporting air for heating a power station boiler, so that cold source loss of the power station is avoided.
Description
Technical Field
The invention relates to the technical field of thermal power generation, in particular to a waste heat recovery system of a thermal power plant.
Background
At present, the installed scale of the thermal power plant in China is approximately 14 hundred million kilowatts, but the energy utilization efficiency of the thermal power plant is only 20% -40%, and the energy utilization efficiency of the thermal power plant is improved, so that the thermal power plant has become urgent demands of enterprises.
The method is influenced by the environmental temperature, the exhaust pressure of a steam turbine of a thermal power plant is about 0.008MPa, the corresponding saturation temperature is 41 ℃, main steam enters a condenser to be absorbed and condensed by circulating water after the expansion work of the steam turbine is reduced to the exhaust pressure, the inlet of the circulating water is about 30 ℃, the outlet of the circulating water is about 39 ℃, and the heat accounts for more than 60% of the energy of the whole plant, but the grade is too low, so that the heat is difficult to directly utilize.
In addition, the water vapor content in the flue gas of the power station boiler reaches 10% -30%, the dew point of the water in the flue gas is about 60 ℃, in the prior art, the flue gas of the power station boiler is directly discharged, so that energy waste is caused, the water vapor in the flue gas is also wasted, and in addition, the atmospheric environment is seriously polluted if harmful components such as acid gas, dust and the like in the flue gas are directly discharged without being treated.
Disclosure of Invention
In view of the foregoing, it is necessary to provide a waste heat recovery system for a thermal power plant, so as to solve the technical problems of low energy utilization efficiency and high water resource consumption of the thermal power plant caused by the fact that steam turbine exhaust energy, power station boiler flue gas energy and water vapor in flue gas are not effectively utilized.
In order to achieve the aim, the invention provides a waste heat recovery system of a thermal power plant, which comprises a power plant boiler, a steam turbine, a waste steam waste heat recovery device, a gas-gas heat exchanger, a wet deacidification tower, a flue gas condenser, an induced draft fan, a chimney and a water supplementing mechanism;
the steam outlet of the power station boiler is communicated with the inlet of the steam turbine;
the exhaust steam waste heat recovery device is used for condensing exhaust steam generated by the steam turbine into condensed water and transferring heat generated in the condensation process into combustion-supporting air for heating the power station boiler;
the hot flue gas inlet of the gas-gas heat exchanger is communicated with the flue gas outlet of the power station boiler, and the hot flue gas outlet of the gas-gas heat exchanger is communicated with the flue gas inlet of the wet deacidification tower;
the flue gas inlet of the flue gas condenser is communicated with the flue gas outlet of the wet deacidification tower, the flue gas outlet of the flue gas condenser is communicated with the cold flue gas inlet of the gas-gas heat exchanger, the cold flue gas outlet of the gas-gas heat exchanger is communicated with the inlet of the induced draft fan, and the outlet of the induced draft fan is communicated with the inlet of the chimney;
the water supplementing mechanism is used for supplementing the condensate water obtained by the exhaust steam waste heat recovery device into the power station boiler and supplementing the water obtained by condensation in the flue gas condenser into the wet deacidification tower.
In some embodiments, the exhaust steam waste heat recovery device comprises a heat pump device, a condenser, a circulating water pump and a condensate pump;
the heat pump device is an absorption heat pump device or a compression heat pump device, when the heat pump device is a compression heat pump device, the heat pump device comprises an evaporator, a compressor, a condenser and a throttle valve, wherein the outlet of the evaporator is communicated with the inlet of the compressor, the outlet of the compressor is communicated with one end of the condenser, the other end of the condenser is communicated with one end of the throttle valve, the other end of the throttle valve is communicated with the inlet of the evaporator, and refrigerant liquid is filled in the evaporator;
the gas inlet of the condenser is communicated with the outlet of the steam turbine, a heat exchange tube is arranged in the condenser, the inlet of the heat exchange tube is communicated with the outlet of the circulating water pump, the outlet of the heat exchange tube is communicated with the circulating water inlet of the evaporator, the circulating water outlet of the evaporator is communicated with the inlet of the circulating water pump, and the outlet at the bottom of the condenser is communicated with the inlet of the condensing water pump through a pipeline.
In some embodiments, the compressor is driven by the turbine.
In some embodiments, the water replenishing mechanism comprises a water replenishing pump, a deaerator and a water feeding pump, wherein a plurality of snake-shaped heat exchange tube rows are arranged in the flue gas condenser, the inlets of the snake-shaped tube rows are communicated with the outlet of the condensate pump, the outlets of the snake-shaped tube rows are communicated with the inlet of the deaerator, the outlet of the deaerator is communicated with the inlet of the water feeding pump, and the water feeding pump is used for supplying water to the power station boiler;
the upper portion of flue gas condenser establishes defogging device, flue gas condenser's lower part is provided with condensate tank, condensate tank's import and flue gas condenser's comdenstion water export intercommunication, condensate tank's export and moisturizing pump's import intercommunication, the condensate tank side is equipped with charge device, moisturizing pump's export and wet deacidification tower's moisturizing mouth of a river intercommunication.
In some embodiments, the serpentine tube array comprises a plurality of light tubes arranged side by side, the light tubes having a gauge of 10mm in diameter and 1mm in thickness.
In some embodiments, the flue gas in the flue gas condenser flows from bottom to top, and the flow rate is 5-7 m/s.
In some embodiments, the demister is a two-layer glass fiber reinforced plastic wave demister.
In some embodiments, the transverse pitch and the longitudinal pitch of the serpentine tube rows are 20mm.
In some embodiments, the gas-gas heat exchanger is a tube array heat exchanger, the upper tube plate and the lower tube plate of the gas-gas heat exchanger are made of Q235 material, the thickness is 20-30 mm, and the tube array of the gas-gas heat exchanger adopts corrosion-resistant ND steel H-shaped fin tubes.
In some embodiments, the flow rate of the hot flue gas in the gas-gas heat exchanger is controlled to be 10-14 m/s, and the flow rate of the cold flue gas in the gas-gas heat exchanger is controlled to be 45% -55% of the flow rate of the hot flue gas.
Compared with the prior art, the technical scheme provided by the invention has the beneficial effects that: the latent heat of vaporization of the vapor in the flue gas discharged from the power station boiler is fully recovered and then is used for heating the condensed water, so that the heating vapor amount consumed by the deaerator is reduced, when the vapor in the flue gas is condensed into condensed water, part of harmful components such as acid gas, dust and the like are also dissolved in the condensed water, the pollutant emission concentration in the flue gas is reduced, and meanwhile, the condensed water is recovered as the water supplement of the wet deacidification tower after the chemical adding treatment, so that the consumption of water resources in the deacidification process is reduced; meanwhile, the exhaust steam waste heat recovery device transfers the heat of the exhaust steam generated by the steam turbine to the combustion-supporting air for heating the power station boiler, so that the heat loss of the power station is avoided, a circulating water cooling tower is not required to be built, and the construction investment of the thermal power station is reduced.
Drawings
FIG. 1 is a schematic diagram of a heat recovery system of a thermal power plant according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of the front view of the gas-gas heat exchanger of FIG. 1;
FIG. 3 is a schematic cross-sectional view of the gas-gas heat exchanger of FIG. 2;
FIG. 4 is a schematic view of the internal structure of the flue gas condenser of FIG. 1;
in the figure: 1-heat pump device, 101-evaporator, 102-compressor, 103-condenser, 104-throttle valve, 2-power station boiler, 201-main steam header, 202-main steam pipeline, 3-steam turbine, 4-condenser, 401-heat exchange tube, 5-circulating water pump, 6-condensate pump, 7-gas heat exchanger, 701-hot flue gas inlet, 702-hot flue gas outlet, 703-cold flue gas inlet, 704-cold flue gas outlet, 8-wet deacidification tower, 801-water supplementing port, 9-flue gas condenser, 901-serpentine tube bank, 902-defogging device, 903-condensate tank, 904-dosing device, 10-induced draft fan, 11-chimney, 12-water supplementing pump, 13-deaerator, 14-water feeding pump.
Detailed Description
Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and together with the description serve to explain the principles of the invention, and are not intended to limit the scope of the invention.
Referring to fig. 1-3, the invention provides a waste heat recovery system of a thermal power plant, which comprises a power station boiler 2, a steam turbine 3, a waste steam waste heat recovery device, a gas-gas heat exchanger 7, a wet deacidification tower 8, a flue gas condenser 9, an induced draft fan 10, a chimney 11 and a water supplementing mechanism.
The tail part of the utility boiler 2 is a flue gas outlet, the top of the utility boiler 2 is provided with a main steam header 201, and the outlet of the main steam header 201 is communicated with the inlet of the steam turbine 3 through a main steam pipeline 202. The steam turbine 3 is used for power generation of a thermal power plant.
The exhaust steam waste heat recovery device is used for transferring heat of exhaust steam generated by the steam turbine 3 to combustion-supporting air for heating the power station boiler 2.
Specifically, the exhaust steam waste heat recovery device comprises a heat pump device 1, wherein the heat pump device 1 is an absorption heat pump device or a compression heat pump device, when the heat pump device 1 is a compression heat pump device, the heat pump device 1 comprises an evaporator 101, a compressor 102, a condenser 103 and a throttle valve 104, an outlet of the evaporator 101 is communicated with an inlet of the compressor 102, an outlet of the compressor 102 is communicated with one end of the condenser 103, the other end of the condenser 103 is communicated with one end of the throttle valve 104, the other end of the throttle valve 104 is communicated with an inlet of the evaporator 101, and refrigerant liquid is filled in the evaporator 101.
The exhaust steam waste heat recovery device further comprises a condenser 4, a circulating water pump 5 and a condensate water pump 6, wherein a gas inlet of the condenser 4 is communicated with an outlet of the steam turbine 3, a heat exchange tube 401 is arranged inside the condenser 4, an inlet of the heat exchange tube 401 is communicated with an outlet of the circulating water pump 5, an outlet of the heat exchange tube 401 is communicated with a circulating water inlet of the evaporator 101, a circulating water outlet of the evaporator 101 is communicated with an inlet of the circulating water pump 5, and a bottom outlet of the condenser 4 is communicated with an inlet of the condensate water pump 6 through a pipeline.
The working principle of the exhaust steam waste heat recovery device is as follows: the pressure of the discharged steam after the steam turbine 3 generates electricity is about 0.008MPa, the corresponding saturation temperature is 41 ℃, the pressure of the main steam discharged from the outlet of the main steam header 201 is reduced to the pressure of the discharged steam after the steam turbine 3 expands to do work to generate electricity, and the main steam enters the condenser 4 to be condensed after being absorbed by circulating water flowing through the heat exchange tube 401. The circulating water inlet of the heat exchange tube 401 is about 30 ℃, the circulating water outlet of the heat exchange tube 401 is about 39 ℃, the circulating water outlet enters the evaporator 101 to exchange heat with the refrigerant liquid and is reduced to 30 ℃, and the circulating water is sent back to the circulating water of the heat exchange tube 401 by the circulating water pump 5 to circulate. The refrigerant liquid in the evaporator 101 is evaporated into saturated vapor after absorbing heat, the saturated vapor is compressed into superheated vapor by the compressor 102 and enters the condenser 103, the condenser 103 is filled with 30 ℃ ambient air, the ambient air is heated into about 90 ℃ hot air by the superheated vapor of the refrigerant in the condenser 103, the superheated vapor of the refrigerant is condensed into saturated liquid in the condenser 103, the saturated liquid is cooled and depressurized by the throttle valve 104 to become the refrigerant liquid, the refrigerant liquid flows back to the evaporator 101, the refrigerant is recycled in the heat pump device 1, and the heated hot air is sent into the utility boiler 2 as combustion-supporting air through a pipeline.
Preferably, the compressor 102 is driven by the steam turbine 3, so that there is no need to additionally provide power for the operation of the compressor 102.
Referring to fig. 1 and 2, the gas-gas heat exchanger 7 is a tube array heat exchanger, a hot flue gas inlet 701 is formed in the upper portion of the tube array heat exchanger, a hot flue gas outlet 702 is formed in the lower portion of the tube array heat exchanger, a cold flue gas inlet 703 is formed in the left side of the tube array heat exchanger, a cold flue gas outlet 704 is formed in the right side of the tube array heat exchanger, the hot flue gas inlet 701 is communicated with a flue gas outlet of the utility boiler 2, and the hot flue gas outlet 702 is communicated with a flue gas inlet of the wet deacidification tower 8.
The upper tube plate and the lower tube plate of the gas-gas heat exchanger 7 are made of Q235 material and have the thickness of 20-30 mm, the tube array of the gas-gas heat exchanger 7 adopts corrosion-resistant ND steel H-shaped fin tubes, the tube diameters of the fin tubes are D=32 mm or 38mm, the thickness delta 1 of the fin tubes is 3-4 mm, the fin height is H=10-15 mm, the thickness of the fin is delta 2=1-2 mm, and the transverse spacing of the tube array of the gas-gas heat exchanger 7 is as follows: s1=1.5×d+2h to 1.75×d+2h, and the longitudinal spacing s2= (d+2h) to 1.25×d+2h of the tubes of the gas-gas heat exchanger 7.
The flow rate of hot flue gas in the gas-gas heat exchanger 7 is controlled to be 10-14 m/s, and the flow rate of cold flue gas in the gas-gas heat exchanger 7 is controlled to be 45% -55% of the flow rate of hot flue gas.
The upper part of the wet deacidification tower 8 is provided with a water supplementing port 801, and the flow rate of the flue gas in the wet deacidification tower 8 is 3-4 m/s.
Referring to fig. 1 and 3, the flue gas inlet of the flue gas condenser 9 is communicated with the flue gas outlet of the wet deacidification tower 8, the flue gas outlet of the flue gas condenser 9 is communicated with the cold flue gas inlet 703 of the gas-gas heat exchanger 7, the cold flue gas outlet 704 of the gas-gas heat exchanger 7 is communicated with the inlet of the induced draft fan 10, and the outlet of the induced draft fan 10 is communicated with the inlet of the chimney 11.
The water supplementing mechanism is used for supplementing condensation water obtained by the exhaust steam waste heat recovery device into a power station boiler and supplementing water obtained by condensation in the flue gas condenser 9 into the wet deacidification tower 8.
Specifically, the water replenishing mechanism includes a water replenishing pump 12, a deaerator 13, and a water feeding pump 14.
The flue gas condenser 9 is internally provided with a plurality of snake-shaped heat exchange tube rows 901, the inlets of the snake-shaped tube rows 901 are communicated with the outlets of the condensate pumps 6, the outlets of the snake-shaped tube rows 901 are communicated with the inlets of the deaerators 13, the outlets of the deaerators 13 are communicated with the inlets of the water feeding pumps 14, and the water feeding pumps 14 are used for supplying water to the utility boilers.
Specifically, the serpentine tube row 901 includes a plurality of light tubes arranged side by side, the light tubes are made of fluoroplastic, the light tube has a diameter d=10mm and a thickness δ=1mm, and the transverse pitch s1=the longitudinal pitch s2=20mm of the serpentine tube row 901.
The flue gas in the flue gas condenser 9 flows from bottom to top, and the flow speed is 5-7 m/s.
The upper portion of flue gas condenser 9 is established defogging device 902, defogging device 902 is the wave form defroster of two-layer glass steel.
The hot flue gas generated by the incineration of the utility boiler 2 is cooled to about 180 ℃ after entering the gas-gas heat exchanger 7 and enters the wet deacidification tower 8, the flue gas is further reduced to about 60 ℃ of the dew point of the flue gas water after deacidification treatment in the wet deacidification tower 8, the flue gas at the moment absorbs the moisture in the wet deacidification tower 8 to become wet saturated flue gas, the wet saturated flue gas at the temperature of 60 ℃ enters the flue gas condenser 9 to exchange heat with the condensation water at the temperature of about 40 ℃ sent by the condensate pump 6, the condensation water absorbs the vaporization latent heat released by condensation of the vapor in the flue gas and rises to 55 ℃, the condensation water absorbing the heat of the flue gas is deoxidized in the deaerator 13, the water is supplied to the utility boiler 2 through the water supply pump 14, the flue gas temperature is reduced from 60 ℃ to the new dew point of the flue gas water 55 ℃ when the vapor in the flue gas condenser 9 is subjected to heat exchange condensation in the liquid water, the cold flue gas at the temperature of 55 ℃ after the flue gas condenser 9 is subjected to removal of condensed water carried by the flue gas through the flue gas device 902, the condensed water is heated to about 120 ℃ by the wet saturated flue gas, and discharged to the chimney 11 through the induced draft fan 10.
Referring to fig. 1 and 3, a condensate tank 903 is disposed at the lower part of the flue gas condenser 9, an inlet of the condensate tank 903 is communicated with a condensate outlet of the flue gas condenser 9, an outlet of the condensate tank 903 is communicated with an inlet of a water supplementing pump 12, a dosing device 904 is disposed on a side surface of the condensate tank 9, an outlet of the water supplementing pump 12 is communicated with a water supplementing port 801 of the wet deacidification tower 8, when in use, water vapor in the flue gas exchanges heat in the flue gas condenser 9 and condenses into liquid and then flows into the condensate tank 903, alkaline agent is added into the condensate tank 9 by the dosing device 904, acidic condensate water is neutralized to be alkaline, and the neutralized condensate water is sent into the water supplementing port 801 of the wet deacidification tower 8 through the water supplementing pump 12 to serve as water supplementing of the wet deacidification tower 8.
According to the waste heat recovery system of the thermal power plant, provided by the invention, the latent heat of vaporization of the vapor in the flue gas is fully recovered and then is used for heating the condensed water, so that the temperature of the condensed water is increased, the heating vapor amount consumed by the deaerator is reduced, when the vapor of the flue gas is condensed into condensed water, part of harmful components such as acid gas and dust in the vapor of the flue gas are dissolved in the condensed water, the pollutant emission concentration in the flue gas is reduced, and meanwhile, the condensed water is recovered as the water supplement of the wet deacidification tower after the chemical adding treatment, so that the consumption of water resources in the deacidification process is reduced.
It should be understood that the deaerator is one of the key equipment of the boiler and the power generation system, if the deaerator has poor deaeration capability, serious corrosion will be caused to the boiler water supply pipeline, the economizer and other auxiliary equipment, the economic loss caused by the deaerator will be tens or hundreds times of the manufacturing cost of the deaerator, and the national electric power enterprise union therefore provides partial standards for the oxygen content of the water supply of the deaerator of the power station boiler, namely, the main steam pressure is 5.8MPa or less, the oxygen content of the water supply is not more than 15 mu m/L, and the oxygen content of the water supply with the main steam pressure of more than 5.8MPa is not more than 7 mu m/L. The spiral film deaerator is a substitute product of a spray filling deaerator, and the principle of the spiral film deaerator is that water is sprayed out from a film lifting pipe in a spiral mode according to a certain angle to be subjected to heat exchange deoxidization with heating steam, and the water is heated to a saturation temperature corresponding to the working pressure of the deaerator to remove oxygen and other gases dissolved in the water, so that corrosion of a boiler water supply pipe, an economizer and other accessory equipment is prevented and reduced.
In addition, the heat pump device is used for recycling low-grade heat of the condenser circulating water, so that the cold source loss of the power plant is avoided, a circulating water cooling tower is not required to be built, and the construction investment of the thermal power plant is reduced.
In summary, the technical scheme provided by the invention has the following beneficial effects:
(1) Exhaust steam discharged after turbine power generation enters condenser 4, be provided with heat exchange tube 401 in condenser 4 and condense exhaust steam, that is to say, exhaust steam condensation released heat has been taken away by the circulating water in heat exchange tube 401, this part of heat is the place that thermal power factory energy loss is biggest, about account for 60% of total energy loss, this technical scheme has retrieved this part of energy loss, retrieve the back through heat pump device 1, be used for heating the combustion-supporting wind of power station boiler 2, namely can rough estimation, avoided about 60% of heat loss:
(2) In the technical scheme, the flue gas temperature is reduced to be below the dew point of water by a flue gas condenser 9, so that sensible heat in the flue gas and latent heat in the flue gas (the latent heat is the heat released by condensing a large amount of water vapor in the flue gas of the power station boiler) are recovered;
(3) After the sensible heat and the latent heat of the water vapor in the flue gas exhausted by the utility boiler 2 are recovered, the water vapor is condensed into water, and the water absorbs some harmful components such as acid gas, dust and the like in the flue gas, so that the pollutant emission concentration in the flue gas is reduced, and meanwhile, the acidic condensed water is changed into alkaline by adding chemicals and then is sent back to the wet deacidification tower 8, so that the advantage is that: in the wet deacidification process, a large amount of water is dissolved in the flue gas and taken away, so that water resource consumption is serious, new water is required to be continuously supplemented into the deacidification tower, and water obtained by condensing vapor in the flue gas can be recovered in the scheme, and the water is basically not required to be supplemented into the wet deacidification tower 8, so that the consumption of water resource is greatly reduced.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the technical scope of the present invention should be included in the scope of the present invention.
Claims (10)
1. The waste heat recovery system of the thermal power plant is characterized by comprising a power station boiler, a steam turbine, a waste steam waste heat recovery device, a gas-gas heat exchanger, a wet deacidification tower, a flue gas condenser, an induced draft fan, a chimney and a water supplementing mechanism;
the steam outlet of the power station boiler is communicated with the inlet of the steam turbine;
the exhaust steam waste heat recovery device is used for condensing exhaust steam generated by the steam turbine into condensed water and transferring heat generated in the condensation process into combustion-supporting air for heating the power station boiler;
the hot flue gas inlet of the gas-gas heat exchanger is communicated with the flue gas outlet of the power station boiler, and the hot flue gas outlet of the gas-gas heat exchanger is communicated with the flue gas inlet of the wet deacidification tower;
the flue gas inlet of the flue gas condenser is communicated with the flue gas outlet of the wet deacidification tower, the flue gas outlet of the flue gas condenser is communicated with the cold flue gas inlet of the gas-gas heat exchanger, the cold flue gas outlet of the gas-gas heat exchanger is communicated with the inlet of the induced draft fan, and the outlet of the induced draft fan is communicated with the inlet of the chimney;
the water supplementing mechanism is used for supplementing the condensate water obtained by the exhaust steam waste heat recovery device into the power station boiler and supplementing the water obtained by condensation in the flue gas condenser into the wet deacidification tower.
2. The heat power plant waste heat recovery system according to claim 1, wherein the exhaust steam waste heat recovery device comprises a heat pump device, a condenser, a circulating water pump and a condensate pump;
the heat pump device is an absorption heat pump device or a compression heat pump device, when the heat pump device is a compression heat pump device, the heat pump device comprises an evaporator, a compressor, a condenser and a throttle valve, wherein the outlet of the evaporator is communicated with the inlet of the compressor, the outlet of the compressor is communicated with one end of the condenser, the other end of the condenser is communicated with one end of the throttle valve, the other end of the throttle valve is communicated with the inlet of the evaporator, and refrigerant liquid is filled in the evaporator;
the gas inlet of the condenser is communicated with the outlet of the steam turbine, a heat exchange tube is arranged in the condenser, the inlet of the heat exchange tube is communicated with the outlet of the circulating water pump, the outlet of the heat exchange tube is communicated with the circulating water inlet of the evaporator, the circulating water outlet of the evaporator is communicated with the inlet of the circulating water pump, and the outlet at the bottom of the condenser is communicated with the inlet of the condensing water pump through a pipeline.
3. The heat power plant waste heat recovery system according to claim 2, wherein the compressor is driven by the steam turbine.
4. The waste heat recovery system of a thermal power plant according to claim 2, wherein the water replenishing mechanism comprises a water replenishing pump, a deaerator and a water feeding pump, a plurality of snake-shaped heat exchange tube rows are arranged in the flue gas condenser, an inlet of each snake-shaped tube row is communicated with an outlet of the condensate pump, an outlet of each snake-shaped tube row is communicated with an inlet of the deaerator, an outlet of the deaerator is communicated with an inlet of the water feeding pump, and the water feeding pump is used for supplying water to a power station boiler;
the upper portion of flue gas condenser establishes defogging device, flue gas condenser's lower part is provided with condensate tank, condensate tank's import and flue gas condenser's comdenstion water export intercommunication, condensate tank's export and moisturizing pump's import intercommunication, the condensate tank side is equipped with charge device, moisturizing pump's export and wet deacidification tower's moisturizing mouth of a river intercommunication.
5. The heat recovery system of claim 4, wherein the serpentine tube array comprises a plurality of light tubes arranged side by side, the light tubes having a diameter of 10mm and a thickness of 1mm.
6. The heat recovery system of a thermal power plant according to claim 4, wherein the flue gas in the flue gas condenser flows from bottom to top at a flow rate of 5-7 m/s.
7. The waste heat recovery system of a thermal power plant according to claim 4, wherein the demister is a two-layer glass fiber reinforced plastic wave-shaped demister.
8. The heat power plant waste heat recovery system of claim 4, wherein the transverse pitch and the longitudinal pitch of the serpentine tube rows are 20mm.
9. The heat recovery system of a thermal power plant according to claim 1, wherein the gas-gas heat exchanger is a tube array heat exchanger, an upper tube plate and a lower tube plate of the gas-gas heat exchanger are made of Q235 material, the thickness is 20-30 mm, and the tube array of the gas-gas heat exchanger adopts corrosion-resistant ND steel H-shaped fin tubes.
10. The waste heat recovery system of a thermal power plant according to claim 1, wherein the flow rate of hot flue gas in the gas-gas heat exchanger is controlled to be 10-14 m/s, and the flow rate of cold flue gas in the gas-gas heat exchanger is controlled to be 45% -55% of the flow rate of hot flue gas.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311560648.XA CN117663103A (en) | 2023-11-20 | 2023-11-20 | Waste heat recovery system of thermal power plant |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311560648.XA CN117663103A (en) | 2023-11-20 | 2023-11-20 | Waste heat recovery system of thermal power plant |
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| CN117663103A true CN117663103A (en) | 2024-03-08 |
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