CN115247784B - Power plant waste heat utilization system and use method - Google Patents

Power plant waste heat utilization system and use method Download PDF

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Publication number
CN115247784B
CN115247784B CN202210817850.5A CN202210817850A CN115247784B CN 115247784 B CN115247784 B CN 115247784B CN 202210817850 A CN202210817850 A CN 202210817850A CN 115247784 B CN115247784 B CN 115247784B
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China
Prior art keywords
control valve
water
valve
heat exchanger
water pump
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CN115247784A (en
Inventor
罗浩东
向魁
林燕
仲伟龙
施海云
王东雷
王晓东
张赢
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China Energy Engineering Group Guangdong Electric Power Design Institute Co Ltd
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China Energy Engineering Group Guangdong Electric Power Design Institute Co Ltd
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22STEAM GENERATION
    • F22DPREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D1/00Feed-water heaters, i.e. economisers or like preheaters
    • F22D1/003Feed-water heater systems
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B15/00Sorption machines, plants or systems, operating continuously, e.g. absorption type
    • F25B15/02Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas
    • F25B15/06Sorption machines, plants or systems, operating continuously, e.g. absorption type without inert gas the refrigerant being water vapour evaporated from a salt solution, e.g. lithium bromide
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25BREFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B27/00Machines, plants or systems, using particular sources of energy
    • F25B27/02Machines, plants or systems, using particular sources of energy using waste heat, e.g. from internal-combustion engines
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28DHEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0001Recuperative heat exchangers
    • F28D21/0012Recuperative heat exchangers the heat being recuperated from waste water or from condensates
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28HEAT EXCHANGE IN GENERAL
    • F28FDETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
    • F28F27/00Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
    • F28F27/02Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus for controlling the distribution of heat-exchange media between different channels

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)
  • Engine Equipment That Uses Special Cycles (AREA)

Abstract

The invention relates to the technical field of power plant preheating utilization, in particular to a power plant waste heat utilization system and a use method thereof, wherein the power plant waste heat utilization system comprises a first low-pressure economizer, a first flow regulating valve, a first heat exchanger, a second heat exchanger, a three-way regulating valve and a first water pump, the first heat exchanger is used for heating lithium bromide aqueous solution of a refrigeration station, and the second heat exchanger is used for preheating natural gas of a natural gas pressure regulating station; the water outlet of the first low-pressure economizer, the first flow regulating valve, the water inlet end of the three-way regulating valve, the first water outlet end of the three-way regulating valve, the first heat exchanger, the second heat exchanger, the first water pump and the water inlet of the first low-pressure economizer are sequentially communicated to form a circulation loop; the hot water flow of the first flow regulating valve is larger than or equal to the lowest drainage amount of the first water pump, so that cavitation of the first water pump is avoided; the backwater of the first heat exchanger is led into the second heat exchanger to preheat natural gas, so that the stepped utilization of heat is realized; the heat utilization efficiency is improved.

Description

Power plant waste heat utilization system and use method
Technical Field
The invention relates to the technical field of power plant waste heat utilization, in particular to a power plant waste heat utilization system and a using method.
Background
In order to comprehensively utilize energy, part of power plants can use hot water in the low-pressure economizer as a heat source to preheat natural gas in the natural gas pressure regulating station or use the hot water in the low-pressure economizer as a heat source to heat lithium bromide water solution in the vaporization refrigerating station. Fig. 1 is a schematic diagram of a currently-used power plant waste heat utilization system, as shown in fig. 1, a water outlet of a first low-pressure economizer is provided with a first flow regulating valve, the other end of the first flow regulating valve is connected with a first heat exchanger of a natural gas pressure regulating station, the hot water quantity supplied by the first economizer to the first heat exchanger is regulated through the first flow regulating valve, and backwater of the first heat exchanger is conveyed back to the first economizer through a first water pump; and a second flow regulating valve is arranged at the water outlet of the second low-pressure economizer, the other end of the second flow regulating valve is connected with a second heat exchanger of the refrigerating station, the hot water quantity supplied by the second heat exchange intensity is regulated through the second flow regulating valve, and backwater of the second heat exchanger is conveyed back to the second economizer through a second water pump.
The hot water quantity requirements of the natural gas pressure regulating station and the refrigerating station are changed greatly, so that the standard drainage flow of the first water pump and the second water pump is larger in order to ensure the use requirements of the hot water quantity of the natural gas pressure regulating station and the refrigerating station when the load is larger; when the hot water load of the natural gas pressure regulating station and the refrigerating station is small, the water flow is required to be reduced through a first flow regulating valve and a second flow regulating valve; however, a decrease in water flow may result in the actual water intake of the first and second water pumps being less than the standard water intake of the first and second water pumps, resulting in cavitation of the first and second water pumps such that the first and second water pumps have a low lifetime.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: in the existing power plant waste heat utilization system, cavitation easily occurs in a first water pump connected with a natural gas pressure regulating station and a second water pump connected with a refrigerating station.
In order to solve the technical problems, the invention aims to provide a power plant waste heat utilization system which comprises a first low-pressure economizer, a first flow regulating valve, a first heat exchanger, a second heat exchanger, a three-way regulating valve and a first water pump, wherein the first heat exchanger is used for heating a lithium bromide aqueous solution of a refrigeration station, and the second heat exchanger is used for preheating natural gas of a natural gas pressure regulating station;
the water outlet of the first low-pressure economizer, the first flow regulating valve, the water inlet end of the three-way regulating valve, the first water outlet end of the three-way regulating valve, the first heat exchanger, the second heat exchanger, the first water pump and the water inlet of the first low-pressure economizer are sequentially communicated to form a circulation loop; the hot water flow of the first flow regulating valve is larger than or equal to the lowest drainage amount of the first water pump; and the second water outlet end of the three-way regulating valve is communicated with the water inlet of the second heat exchanger.
As an optimal scheme, the power plant waste heat utilization system comprises a second flow regulating valve, wherein a second water outlet end of the three-way regulating valve, a water return port of the first heat exchanger and a water outlet of the first low-pressure economizer are communicated with a water inlet of the second flow regulating valve, and a water outlet of the second flow regulating valve is communicated with a water inlet of the second heat exchanger.
As a preferred scheme, the power plant waste heat utilization system comprises a first three-way valve, a first port of the first three-way valve is communicated with a water outlet of the first low-pressure economizer, a second port of the first three-way valve is communicated with a water inlet of the first flow regulating valve, a third port of the first three-way valve is connected with a first pipeline, the other end of the first pipeline is connected with a water inlet of the second flow regulating valve, and a first control valve is arranged on the first pipeline.
As a preferable scheme, the power plant waste heat utilization system comprises a second low-pressure economizer and a second water pump, wherein a second water outlet end of the three-way regulating valve is communicated with a water inlet of the first flow regulating valve, a water return port of the first heat exchanger is communicated with a water inlet of the first flow regulating valve through a second pipeline, and a second control valve is arranged on the second pipeline; the second water outlet end of the three-way regulating valve is communicated with the water inlet of the second water pump, and the water return port of the first heat exchanger is communicated with the water inlet of the second water pump through a third pipeline which is provided with a third control valve; the water outlet of the second water pump is communicated with the water return port of the first low-pressure economizer through a fourth control valve;
the water outlet of the second low-pressure economizer is communicated with the water inlet of the second flow regulating valve; a fifth control valve is arranged between the water outlet of the first water pump and the water inlet of the first low-pressure economizer, the water outlet of the first water pump is communicated with the water inlet of the second low-pressure economizer through a fourth pipeline, and a sixth control valve is arranged on the fourth pipeline.
As an optimal scheme, the power plant waste heat utilization system comprises a seventh control valve, one end of the seventh control valve is connected with the water outlet of the second low-pressure economizer, and the other end of the seventh control valve is connected with the water inlet of the second flow regulating valve.
As a preferable scheme, the power plant waste heat utilization system comprises a third water pump, wherein the water return port of the first heat exchanger, the water return port of the second heat exchanger and the second water outlet end of the three-way regulating valve are communicated with the water inlet of the third water pump, and the water inlet of the first low-pressure economizer and the water inlet of the second low-pressure economizer are communicated with the water outlet of the third water pump.
As a preferable scheme, an eighth control valve is arranged between the water inlet of the third water pump and the water return port of the second heat exchanger; a water inlet of the third water pump is connected with a ninth control valve, and a water return port of the first heat exchanger and a second water outlet end of the three-way regulating valve are both connected with the other end of the ninth control valve; a tenth control valve is arranged between the water outlet of the third water pump and the water inlet of the first low-pressure economizer; an eleventh control valve is arranged between the water outlet of the third water pump and the water inlet of the second low-pressure economizer.
As a preferable scheme, a twelfth control valve is arranged between the water inlet of the first water pump and the water return port of the second heat exchanger.
In the application method of the power plant waste heat utilization system, when the refrigerating station and the natural gas pressure regulating station are in low load, the first water pump is started; adjusting the first flow regulating valve so that the flow rate of the hot water entering the first flow regulating valve is greater than or equal to the lowest displacement of the first water pump; closing the first control valve, the third control valve, the eighth control valve, the ninth control valve, the tenth control valve, the eleventh control valve, the sixth control valve, and opening the second control valve, the twelfth control valve, and the fifth control valve;
the refrigeration station and the natural gas pressure regulating station are at medium load; closing the third control valve, the eighth control valve, the ninth control valve, the tenth control valve, the eleventh control valve, the sixth control valve, and opening the first control valve, the second control valve, the twelfth control valve, and the fifth control valve;
when the refrigerating station and the natural gas pressure regulating station are in high load, the first water pump and the second water pump are started; adjusting the first flow regulating valve so that the flow rate of the hot water entering the first flow regulating valve is greater than or equal to the lowest displacement of the second water pump; adjusting a second flow rate adjusting valve so that the flow rate of the hot water entering the second flow rate adjusting valve is greater than or equal to the lowest displacement of the first water pump; closing the first control valve, the second control valve, the eighth control valve, the ninth control valve, the tenth control valve, the eleventh control valve, the fifth control valve, and opening the third control valve, the fourth control valve, the seventh control valve, the twelfth control valve, and the sixth control valve.
As a preferable scheme, the refrigerating station and the natural gas pressure regulating station are under high load, when the first water pump fails, the first water pump is closed, and the third water pump is started; adjusting the second flow rate adjusting valve so that the flow rate of the hot water entering the second flow rate adjusting valve is equal to or greater than the lowest displacement of the third water pump; closing the twelfth control valve, the first control valve, the second control valve, the ninth control valve, the eleventh control valve, the fifth control valve, and opening the third control valve, the fourth control valve, the seventh control valve, the eighth control valve, and the tenth control valve.
Compared with the prior art, the invention has the beneficial effects that:
the invention relates to a power plant waste heat utilization system, which comprises a first low-pressure economizer, a first flow regulating valve, a first heat exchanger, a second heat exchanger, a three-way regulating valve and a first water pump, wherein the first heat exchanger is used for heating lithium bromide aqueous solution of a refrigeration station, and the second heat exchanger is used for preheating natural gas of a natural gas pressure regulating station; the water outlet of the first low-pressure economizer, the first flow regulating valve, the water inlet end of the three-way regulating valve, the first water outlet end of the three-way regulating valve, the first heat exchanger, the second heat exchanger, the first water pump and the water inlet of the first low-pressure economizer are sequentially communicated to form a circulation loop; the hot water flow of the first flow regulating valve is larger than or equal to the lowest drainage amount of the first water pump, so that cavitation of the first water pump is avoided; a part of hot water flowing out of the first flow regulating valve flows into the first heat exchanger through a first water outlet end of the three-way regulating valve, and the lithium bromide aqueous solution in the first heat exchanger is heated; the temperature of the backwater of the first heat exchanger after the lithium bromide is heated is higher, and the backwater of the first heat exchanger is introduced into the second heat exchanger to preheat natural gas, so that the stepped utilization of heat is realized, and the heat utilization efficiency is improved; the other part of the hot water flowing out of the first flow regulating valve is communicated with the water inlet of the second heat exchanger through the second water outlet end of the three-way regulating valve, and the hot water quantity entering the first heat exchanger and the hot water quantity entering the second heat exchanger are regulated through the three-way regulating valve, so that the distribution of the hot water quantity entering the first heat exchanger and the hot water quantity entering the second heat exchanger can be realized, and the power plant waste heat utilization system can flexibly distribute the hot water flow according to the load of the pressure regulating station and the load of the natural gas station.
Drawings
FIG. 1 is a schematic diagram of the operation of the power plant waste heat utilization system of the present invention with refrigeration and natural gas pressure regulating stations at low load;
FIG. 2 is a schematic diagram of the operation of the power plant waste heat utilization system of the present invention with the refrigeration and natural gas pressure regulating stations at medium load;
FIG. 3 is a schematic diagram of the operation of the power plant waste heat utilization system of the present invention with the refrigeration and natural gas pressure regulating stations at high load;
in the figure, 1, a first low-pressure economizer; 2. a first flow regulating valve; 3. a first heat exchanger; 4. a second heat exchanger; 5. a three-way regulating valve; 6. a first water pump; 7. a second flow regulating valve; 8. a first three-way valve; 9. a first pipeline; 10. a first control valve; 11. a second low pressure economizer; 12. a second water pump; 13. a second pipeline; 14. a second control valve; 15. a third pipeline; 16. a third control valve; 17. a fourth control valve; 18. a fifth control valve; 19. a fourth pipeline; 20. a sixth control valve; 21. a seventh control valve; 22. a third water pump; 23. an eighth control valve; 24. a ninth control valve; 25. a tenth control valve; 26. an eleventh control valve; 27. a twelfth control valve; 28. a fifth pipeline; 29. a thirteenth control valve; 30. a sixth pipeline; 31. fourteenth control valve.
Detailed Description
The following describes in further detail the embodiments of the present invention with reference to the drawings and examples. The following examples are illustrative of the invention and are not intended to limit the scope of the invention.
In the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "top", "bottom", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention. It should be understood that the terms "first," "second," and the like are used herein to describe various information, but such information should not be limited to these terms, which are used merely to distinguish one type of information from another. For example, a "first" message may also be referred to as a "second" message, and similarly, a "second" message may also be referred to as a "first" message, without departing from the scope of the invention.
As shown in fig. 1 to 3, a preferred embodiment of the power plant waste heat utilization system of the present invention includes a first low pressure economizer 1, a first flow rate adjusting valve 2, a first heat exchanger 3, a second heat exchanger 4, a three-way adjusting valve 5 and a first water pump 6, the first heat exchanger 3 is used for heating lithium bromide aqueous solution of a refrigeration station, and the second heat exchanger 4 is used for preheating natural gas of a natural gas pressure regulating station; the water outlet of the first low-pressure economizer 1, the first flow regulating valve 2, the water inlet end of the three-way regulating valve 5, the first water outlet end of the three-way regulating valve 5, the first heat exchanger 3, the second heat exchanger 4, the first water pump 6 and the water inlet of the first low-pressure economizer 1 are sequentially communicated to form a circulation loop; the flow rate of the hot water of the first flow rate adjusting valve 2 is equal to or more than the lowest displacement of the first water pump 6; thereby avoiding cavitation of the first water pump 6, and the second water outlet end of the three-way regulating valve 5 is communicated with the water inlet of the second heat exchanger 4. A part of hot water flowing out of the first flow regulating valve 2 flows into the first heat exchanger 3 through the first water outlet end of the three-way regulating valve 5, and the lithium bromide aqueous solution in the first heat exchanger 3 is heated; the temperature of the backwater after the first heat exchanger 3 heats the lithium bromide is higher, and the backwater of the first heat exchanger 3 is led into the second heat exchanger 4 to preheat natural gas, so that the stepped utilization of heat is realized, and the heat utilization efficiency is improved; the other part of the hot water flowing out of the first flow regulating valve 2 is communicated with the water inlet of the second heat exchanger 4 through the second water outlet end of the three-way regulating valve 5, and the hot water quantity entering the first heat exchanger 3 and the hot water quantity entering the second heat exchanger 4 are regulated through the three-way regulating valve 5, so that the distribution of the hot water quantity entering the first heat exchanger 3 and the hot water quantity entering the second heat exchanger 4 can be realized, and the power plant waste heat utilization system can flexibly distribute the hot water flow according to the load of the pressure regulating station and the load of the natural gas station.
In this embodiment, the waste heat utilization system of the power plant includes a second flow regulating valve 7, a second water outlet end of the three-way regulating valve 5, a water return port of the first heat exchanger 3, and a water outlet of the first low-pressure economizer are all communicated with a water inlet of the second flow regulating valve 7, and a water outlet of the second flow regulating valve 7 is communicated with a water inlet of the second heat exchanger 4. When the loads of the natural gas pressure regulating station and the refrigerating station are high, the hot water quantity entering the first heat exchanger 3 can be controlled by regulating the first flow regulating valve 2 and the three-way regulating valve 5; the hot water quantity entering the first heat exchanger 3 can be controlled by adjusting the first flow regulating valve 2, the three-way regulating valve 5 and the second flow regulating valve 7, so that the power plant waste heat utilization system can distribute the hot water flow more flexibly according to the load of the pressure regulating station and the load of the natural gas station.
Specifically, the waste heat utilization system of the power plant comprises a first three-way valve 8, a first port of the first three-way valve 8 is communicated with a water outlet of the first low-pressure economizer 1, a second port of the first three-way valve 8 is communicated with a water inlet of the first flow regulating valve 2, and a third port of the first three-way valve 8 is communicated with a water inlet of the second flow regulating valve 7; further, a third port of the first three-way valve 8 is connected with a first pipeline 9, the other end of the first pipeline 9 is connected with a water inlet of the second flow regulating valve 7, and a first control valve 10 is arranged on the first pipeline 9.
In the embodiment, the power plant waste heat utilization system comprises a second low-pressure economizer 11 and a second water pump 12, wherein a second water outlet end of the three-way regulating valve 5 is communicated with a water inlet of the first flow regulating valve 2, a water return port of the first heat exchanger 3 is communicated with a water inlet of the first flow regulating valve 2 through a second pipeline 13, and a second control valve 14 is arranged on the second pipeline 13; the second water outlet end of the three-way regulating valve 5 is communicated with the water inlet of the second water pump 12, and the water return port of the first heat exchanger 3 is communicated with the water inlet of the second water pump 12 through a third pipeline 15, and a third control valve 16 is arranged on the third pipeline 15; the water outlet of the second water pump 12 is communicated with the water return port of the first low-pressure economizer 1 through a fourth control valve 17; the water outlet of the second low-pressure economizer 11 is communicated with the water inlet of the second flow regulating valve 7; a fifth control valve 18 is arranged between the water outlet of the first water pump 6 and the water inlet of the first low-pressure economizer 1, the water outlet of the first water pump 6 is communicated with the water inlet of the second low-pressure economizer 11 through a fourth pipeline 19, and a sixth control valve 20 is arranged on the fourth pipeline 19. When the loads of the natural gas pressure regulating station and the refrigerating station are further increased, in order to avoid the influence on the operation of the boiler caused by using the same low-pressure economizer, water is supplied to the first heat exchanger 3 through the first low-pressure economizer 1, and backwater of the first heat exchanger 3 is conveyed to the first low-pressure economizer 1 through the second water pump 12; the water is supplied to the second heat exchanger 4 through the second low-pressure economizer 11, the backwater of the second heat exchanger 4 is conveyed to the second low-pressure economizer 11 through the low-pressure water pump 6, and at the moment, the flow rate of the hot water of the first flow regulating valve 2 is more than or equal to the lowest drainage rate of the second water pump 12, and the flow rate of the hot water of the second flow regulating valve 7 is more than or equal to the lowest drainage rate of the first water pump 6.
Specifically, the waste heat utilization system of the power plant comprises a seventh control valve 21, one end of the seventh control valve 21 is connected with the water outlet of the second low-pressure economizer 11, and the other end of the seventh control valve 21 is connected with the water inlet of the second flow regulating valve 7.
In this embodiment, the power plant waste heat utilization system includes a third water pump 22, the water return port of the first heat exchanger 3, the water return port of the second heat exchanger 4, and the second water outlet end of the three-way regulating valve 5 are all communicated with the water inlet of the third water pump 22, and the water inlet of the first low-pressure economizer 1 and the water inlet of the second low-pressure economizer 11 are both communicated with the water outlet of the third water pump 22. When the first water pump 6 or the second water pump 12 fails, the third water pump 22 is activated, thereby maintaining the hot water supply of the natural gas pressure regulating station or the refrigeration station.
Specifically, an eighth control valve 23 is arranged between the water inlet of the third water pump 22 and the water return port of the second heat exchanger 4; a water inlet of the third water pump 22 is connected with a ninth control valve 24, and a water return port of the first heat exchanger 3 and a second water outlet end of the three-way regulating valve 5 are both connected with the other end of the ninth control valve 24; a tenth control valve 25 is arranged between the water outlet of the third water pump 22 and the water inlet of the first low-pressure economizer 1; an eleventh control valve 26 is arranged between the water outlet of the third water pump 22 and the water inlet of the second low-pressure economizer 11. A twelfth control valve 27 is arranged between the water inlet of the first water pump and the water return port of the second heat exchanger 4.
In the embodiment of the method for using the power plant waste heat utilization system, when the refrigeration station and the natural gas pressure regulating station are in low load, as shown in fig. 1, the first water pump 6 is started; adjusting the first flow rate adjusting valve 2 so that the flow rate of the hot water entering the first flow rate adjusting valve 2 is equal to or greater than the minimum displacement of the first water pump 6; closing the first control valve 10, the third control valve 16, the eighth control valve 23, the ninth control valve 24, the tenth control valve 25, the eleventh control valve 26, the sixth control valve 20, and opening the second control valve 14, the twelfth control valve 27, and the fifth control valve 18;
when the refrigeration station and the natural gas pressure regulating station are in medium load, the first water pump 6 is started; adjusting the first flow rate adjusting valve 2 so that the flow rate of the hot water entering the first flow rate adjusting valve 2 is equal to or greater than the minimum displacement of the first water pump 6; closing the third control valve 16, the eighth control valve 23, the ninth control valve 24, the tenth control valve 25, the eleventh control valve 26, the sixth control valve 20, and opening the first control valve 10, the second control valve 14, the twelfth control valve 27, and the fifth control valve 18;
when the refrigerating station and the natural gas pressure regulating station are under high load, the first water pump 6 and the second water pump 12 are started; adjusting the first flow rate adjustment valve 2 such that the flow rate of the hot water entering the first flow rate adjustment valve 2 is equal to or greater than the lowest displacement of the second water pump 12; the second flow rate adjusting valve 7 is adjusted so that the flow rate of the hot water entering the second flow rate adjusting valve 7 is equal to or more than the lowest displacement of the first water pump 6; the first control valve 10, the second control valve 14, the eighth control valve 23, the ninth control valve 24, the tenth control valve 25, the eleventh control valve 26, the fifth control valve 18 are closed, and the third control valve 16, the fourth control valve 17, the seventh control valve 21, the twelfth control valve 27, and the sixth control valve 20 are opened.
In this embodiment, when the refrigeration station and the natural gas pressure regulating station are under high load and the first water pump 6 fails, the first water pump 6 is turned off and the third water pump 22 is turned on; the second flow rate adjusting valve 7 is adjusted so that the flow rate of the hot water entering the second flow rate adjusting valve 7 is equal to or more than the lowest displacement of the third water pump 22; the twelfth control valve 27, the first control valve 10, the second control valve 14, the ninth control valve 24, the eleventh control valve 26, the fifth control valve 18 are closed, and the third control valve 16, the fourth control valve 17, the seventh control valve 21, the eighth control valve 23, and the tenth control valve 25 are opened.
In other embodiments of the present invention, as shown in fig. 3, the present invention includes a fifth pipeline 28, a thirteenth control valve 29, a sixth pipeline 30 and a fourteenth control valve 31, wherein a first end of the fifth pipeline 28 is communicated with the water inlet of the 11, a water outlet end of the second water pump 12, the eleventh control valve 26 and the fourth control valve 17 are all communicated with a second end of the fifth pipeline 28, and the thirteenth control valve 29 is disposed on the fifth pipeline 28; a first end of the sixth pipeline 30 is arranged between the water outlet of the second low-pressure economizer 11 and the seventh control valve 21, a second end of the sixth pipeline 30 is arranged between the first three-way valve 8 and the first flow regulating valve 2, and a fourteenth control valve 31 is arranged on the sixth pipeline 30; when the fourteenth control valve 31 and the thirteenth control valve 29 are closed and the fourth control valve 17 is opened, the second low-pressure economizer 11 supplies water to the second heat exchanger 4, and the first low-pressure economizer 1 supplies water to the first heat exchanger 3.
In summary, in the power plant waste heat utilization system, the water outlet of the first low-pressure economizer 1, the first flow regulating valve 2, the water inlet end of the three-way regulating valve 5, the first water outlet end of the three-way regulating valve 5, the first heat exchanger 3, the second heat exchanger 4, the first water pump 6 and the water inlet of the first low-pressure economizer 1 are sequentially communicated to form a circulation loop; the flow rate of the hot water of the first flow rate adjusting valve 2 is equal to or more than the lowest displacement of the first water pump 6; thereby avoiding cavitation of the first water pump 6, and the second water outlet end of the three-way regulating valve 5 is communicated with the water inlet of the second heat exchanger 4. A part of hot water flowing out of the first flow regulating valve 2 flows into the first heat exchanger 3 through the first water outlet end of the three-way regulating valve 5, and the lithium bromide aqueous solution in the first heat exchanger 3 is heated; the temperature of the backwater after the first heat exchanger 3 heats the lithium bromide is higher, and the backwater of the first heat exchanger 3 is led into the second heat exchanger 4 to preheat natural gas, so that the stepped utilization of heat is realized, and the heat utilization efficiency is improved; the other part of the hot water flowing out of the first flow regulating valve 2 is communicated with the water inlet of the second heat exchanger 4 through the second water outlet end of the three-way regulating valve 5, and the hot water quantity entering the first heat exchanger 3 and the hot water quantity entering the second heat exchanger 4 are regulated through the three-way regulating valve 5, so that the distribution of the hot water quantity entering the first heat exchanger 3 and the hot water quantity entering the second heat exchanger 4 can be realized, and the power plant waste heat utilization system can flexibly distribute the hot water flow according to the load of the pressure regulating station and the load of the natural gas station.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims (8)

1. The power plant waste heat utilization system is characterized by comprising a first low-pressure economizer (1), a first flow regulating valve (2), a first heat exchanger (3), a second heat exchanger (4), a three-way regulating valve (5) and a first water pump (6), wherein the first heat exchanger (3) is used for heating a lithium bromide aqueous solution of a refrigeration station, and the second heat exchanger (4) is used for preheating natural gas of a natural gas pressure regulating station;
the water outlet of the first low-pressure economizer (1), the first flow regulating valve (2), the water inlet end of the three-way regulating valve (5), the first water outlet end of the three-way regulating valve (5), the first heat exchanger (3), the second heat exchanger (4), the first water pump (6) and the water inlet of the first low-pressure economizer (1) are sequentially communicated to form a circulation loop; the hot water flow of the first flow regulating valve (2) is more than or equal to the lowest drainage of the first water pump (6); the second water outlet end of the three-way regulating valve (5) is communicated with the water inlet of the second heat exchanger (4);
the power plant waste heat utilization system comprises a second flow regulating valve (7), wherein a second water outlet end of the three-way regulating valve (5), a water return port of the first heat exchanger (3) and a water outlet of the first low-pressure economizer are communicated with a water inlet of the second flow regulating valve (7), and a water outlet of the second flow regulating valve (7) is communicated with a water inlet of the second heat exchanger (4);
the power plant waste heat utilization system comprises a second low-pressure economizer (11) and a second water pump (12), wherein a second water outlet end of the three-way regulating valve (5) is communicated with a water inlet of the first flow regulating valve (2), a water return port of the first heat exchanger (3) is communicated with a water inlet of the first flow regulating valve (2) through a second pipeline (13), and a second control valve (14) is arranged on the second pipeline (13); the second water outlet end of the three-way regulating valve (5) is communicated with the water inlet of the second water pump (12), and the water return port of the first heat exchanger (3) is communicated with the water inlet of the second water pump (12) through a third pipeline (15), and a third control valve (16) is arranged on the third pipeline (15); the water outlet of the second water pump (12) is communicated with the water return port of the first low-pressure economizer (1) through a fourth control valve (17);
the water outlet of the second low-pressure economizer (11) is communicated with the water inlet of the second flow regulating valve (7); a fifth control valve (18) is arranged between the water outlet of the first water pump (6) and the water inlet of the first low-pressure economizer (1), the water outlet of the first water pump (6) is communicated with the water inlet of the second low-pressure economizer (11) through a fourth pipeline (19), and a sixth control valve (20) is arranged on the fourth pipeline (19).
2. The power plant waste heat utilization system according to claim 1, characterized in that the power plant waste heat utilization system comprises a first three-way valve (8), a first port of the first three-way valve (8) is communicated with a water outlet of the first low-pressure economizer (1), a second port of the first three-way valve (8) is communicated with a water inlet of the first flow regulating valve (2), a third port of the first three-way valve (8) is connected with a first pipeline (9), the other end of the first pipeline (9) is connected with a water inlet of the second flow regulating valve (7), and a first control valve (10) is arranged on the first pipeline (9).
3. The power plant waste heat utilization system according to claim 2, characterized in that the power plant waste heat utilization system comprises a seventh control valve (21), one end of the seventh control valve (21) is connected with the water outlet of the second low-pressure economizer (11), and the other end of the seventh control valve (21) is connected with the water inlet of the second flow regulating valve (7).
4. A plant waste heat utilization system according to claim 3, characterized in that the plant waste heat utilization system comprises a third water pump (22), the water return port of the first heat exchanger (3), the water return port of the second heat exchanger (4) and the second water outlet end of the three-way regulating valve (5) are all communicated with the water inlet of the third water pump (22), and the water inlet of the first low-pressure economizer (1) and the water inlet of the second low-pressure economizer (11) are both communicated with the water outlet of the third water pump (22).
5. The power plant waste heat utilization system according to claim 4, wherein an eighth control valve (23) is arranged between the water inlet of the third water pump (22) and the water return port of the second heat exchanger (4); a water inlet of the third water pump (22) is connected with a ninth control valve (24), and a water return port of the first heat exchanger (3) and a second water outlet end of the three-way regulating valve (5) are both connected with the other end of the ninth control valve (24); a tenth control valve (25) is arranged between the water outlet of the third water pump (22) and the water inlet of the first low-pressure economizer (1); an eleventh control valve (26) is arranged between the water outlet of the third water pump (22) and the water inlet of the second low-pressure economizer (11).
6. The power plant waste heat utilization system according to claim 5, characterized in that a twelfth control valve (27) is arranged between the water inlet of the first water pump and the water return port of the second heat exchanger (4).
7. A method of using a plant waste heat utilization system according to claim 6, characterized in that the first water pump (6) is turned on when the refrigeration station and the natural gas pressure regulating station are at low load; the first flow rate regulating valve (2) is regulated so that the flow rate of the hot water entering the first flow rate regulating valve (2) is greater than or equal to the lowest drainage rate of the first water pump (6); closing the first control valve (10), the third control valve (16), the eighth control valve (23), the ninth control valve (24), the tenth control valve (25), the eleventh control valve (26), the sixth control valve (20), and opening the second control valve (14), the twelfth control valve (27) and the fifth control valve (18);
the refrigeration station and the natural gas pressure regulating station are at medium load; -closing the third control valve (16), the eighth control valve (23), the ninth control valve (24), the tenth control valve (25), the eleventh control valve (26), the sixth control valve (20), opening the first control valve (10), the second control valve (14), the twelfth control valve (27) and the fifth control valve (18);
when the refrigerating station and the natural gas pressure regulating station are under high load, the first water pump (6) and the second water pump (12) are started; adjusting the first flow rate adjustment valve (2) so that the flow rate of the hot water entering the first flow rate adjustment valve (2) is equal to or greater than the lowest displacement of the second water pump (12); adjusting a second flow rate adjustment valve (7) such that the flow rate of hot water entering the second flow rate adjustment valve (7) is equal to or greater than the lowest displacement of the first water pump (6); -closing the first control valve (10), the second control valve (14), the eighth control valve (23), the ninth control valve (24), the tenth control valve (25), the eleventh control valve (26), the fifth control valve (18), -opening the third control valve (16), the fourth control valve (17), the seventh control valve (21), the twelfth control valve (27) and the sixth control valve (20).
8. The method of using a power plant waste heat utilization system according to claim 7, wherein the refrigeration station and the natural gas pressure regulating station are under high load, when the first water pump (6) fails, the first water pump (6) is turned off, and a third water pump (22) is turned on; -adjusting the second flow rate adjustment valve (7) such that the flow rate of the hot water entering the second flow rate adjustment valve (7) is equal to or greater than the lowest displacement of the third water pump (22); -closing the twelfth control valve (27), the first control valve (10), the second control valve (14), the ninth control valve (24), the eleventh control valve (26), the fifth control valve (18), -opening the third control valve (16), the fourth control valve (17), the seventh control valve (21), the eighth control valve (23) and the tenth control valve (25).
CN202210817850.5A 2022-07-12 2022-07-12 Power plant waste heat utilization system and use method Active CN115247784B (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103206697A (en) * 2013-04-12 2013-07-17 凤阳海泰科能源环境管理服务有限公司 Cooling, heating, power supplying and water supplying combined device capable of utilizing waste heat of flue gas of gas turbine
CN204922357U (en) * 2015-07-16 2015-12-30 上海华电奉贤热电有限公司 Liquefied natural gas heating system
CN211454379U (en) * 2019-12-25 2020-09-08 杭州国能汽轮工程有限公司 Condenser hot well liquid level control system for steam turbine
CN215261251U (en) * 2021-06-29 2021-12-21 无锡华光环保能源集团股份有限公司 Natural gas system of exhaust-heat boiler hot water pumping heating pressure regulating station
CN216767574U (en) * 2021-12-10 2022-06-17 上海申能奉贤热电有限公司 Natural gas heating device

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103206697A (en) * 2013-04-12 2013-07-17 凤阳海泰科能源环境管理服务有限公司 Cooling, heating, power supplying and water supplying combined device capable of utilizing waste heat of flue gas of gas turbine
CN204922357U (en) * 2015-07-16 2015-12-30 上海华电奉贤热电有限公司 Liquefied natural gas heating system
CN211454379U (en) * 2019-12-25 2020-09-08 杭州国能汽轮工程有限公司 Condenser hot well liquid level control system for steam turbine
CN215261251U (en) * 2021-06-29 2021-12-21 无锡华光环保能源集团股份有限公司 Natural gas system of exhaust-heat boiler hot water pumping heating pressure regulating station
CN216767574U (en) * 2021-12-10 2022-06-17 上海申能奉贤热电有限公司 Natural gas heating device

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