CN115342673A - Anti-freezing system for molten salt heat exchange equipment and pipeline and control method - Google Patents
Anti-freezing system for molten salt heat exchange equipment and pipeline and control method Download PDFInfo
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- 150000003839 salts Chemical class 0.000 title claims abstract description 203
- 238000000034 method Methods 0.000 title claims abstract description 17
- 238000007710 freezing Methods 0.000 title abstract description 19
- 239000007788 liquid Substances 0.000 claims abstract description 59
- 238000004146 energy storage Methods 0.000 claims abstract description 43
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 68
- 238000010248 power generation Methods 0.000 claims description 23
- 230000001105 regulatory effect Effects 0.000 claims description 18
- 230000002528 anti-freeze Effects 0.000 claims description 15
- 238000010438 heat treatment Methods 0.000 claims description 12
- 238000010792 warming Methods 0.000 claims description 10
- 238000012544 monitoring process Methods 0.000 claims description 8
- 238000011144 upstream manufacturing Methods 0.000 claims description 6
- 230000001276 controlling effect Effects 0.000 claims description 4
- 108010053481 Antifreeze Proteins Proteins 0.000 claims description 2
- 230000002209 hydrophobic effect Effects 0.000 claims 1
- 238000005265 energy consumption Methods 0.000 abstract description 4
- 238000009833 condensation Methods 0.000 abstract description 2
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- 239000011550 stock solution Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 238000005338 heat storage Methods 0.000 description 2
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- 241000196324 Embryophyta Species 0.000 description 1
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- 238000005496 tempering Methods 0.000 description 1
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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
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D20/0034—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B1/00—Methods of steam generation characterised by form of heating method
- F22B1/02—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers
- F22B1/06—Methods of steam generation characterised by form of heating method by exploitation of the heat content of hot heat carriers the heat carrier being molten; Use of molten metal, e.g. zinc, as heat transfer medium
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
- F22B33/00—Steam-generation plants, e.g. comprising steam boilers of different types in mutual association
- F22B33/18—Combinations of steam boilers with other apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F27/00—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus
- F28F27/02—Control arrangements or safety devices specially adapted for heat-exchange or heat-transfer apparatus for controlling the distribution of heat-exchange media between different channels
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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
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D20/0034—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material
- F28D2020/0047—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00 using liquid heat storage material using molten salts or liquid metals
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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
- F28D20/00—Heat storage plants or apparatus in general; Regenerative heat-exchange apparatus not covered by groups F28D17/00 or F28D19/00
- F28D2020/0065—Details, e.g. particular heat storage tanks, auxiliary members within tanks
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Abstract
The invention discloses an anti-freezing system and a control method for fused salt heat exchange equipment and pipelines. When the heat tracing system is shut down, the liquid level meter, the first thermometer, the pressure gauge, the second thermometer and the like can be monitored through the heat tracing system, when heat tracing is needed, steam in the steam energy storage unit is led out to the existing steam circulation pipeline, heat tracing is carried out on the molten salt through the heat exchange capacity of the steam molten salt heat exchange equipment, and therefore the molten salt is maintained above the condensation temperature. The consumed residual heat energy is only residual heat energy in the external molten salt storage tank, the operation is stable and reliable, and the problems of large energy consumption and low reliability of the conventional electric tracing system are solved.
Description
Technical Field
The invention belongs to the technical field of solar thermal power generation, and particularly relates to an anti-freezing system for molten salt heat exchange equipment and pipelines and a control method.
Background
Molten salt (binary salt) in the solar thermal power generation project is used as a heat storage medium, and the working temperature is higher than the solidification temperature of the molten salt. In order to prevent the liquid molten salt working medium from being solidified in the transferring and storing processes, the commonly adopted method is to lay electric tracing heat between the molten salt pipeline and the outer surface of the molten salt heat exchange equipment and the heat preservation layer, and offset the heat dissipation loss between the molten salt heat exchange equipment and the outside through the electric tracing heat heating, thereby ensuring that the temperature of the molten salt in the heat exchange equipment is above the solidification temperature.
The electric tracing system can realize automatic adjustment through temperature monitoring, and has the defects of higher plant power consumption and higher failure rate, thereby reducing the comprehensive efficiency of the system and increasing the forced shutdown maintenance time. Therefore, a more reliable anti-solidification system is urgently needed in the field of solar thermal power generation molten salt heat storage and exchange.
The main disadvantages of the electric tracing heat used for the molten salt heat exchange equipment are: 1. along with the start and stop of a unit, the temperature of the molten salt working medium is in the process of repeated circulation of temperature rise and temperature reduction, and the insulating layer is easily damaged due to expansion with heat and contraction with cold; 2. the reliability is reduced due to frequent actions of the electrical elements, and the field overhaul workload is large; 3. the unreasonable arrangement of electric tracing heat will cause the local metal to be over-heated, and the metal creep speed is accelerated.
Disclosure of Invention
The invention aims to solve the technical problem of providing an anti-freezing system for molten salt heat exchange equipment and pipelines and a control method thereof, and solving the problems of high energy consumption and low reliability of the conventional electric tracing system.
In order to solve the problems, the technical scheme of the invention is as follows:
the invention discloses an anti-freezing system for molten salt heat exchange equipment and pipelines, which is used for providing back-warm steam to a steam circulating pipeline of an external solar power generation system and comprises:
the steam output end of the back-warming pipeline is communicated with the steam circulation pipeline and is positioned at the upstream of the first steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline; the water return end of the back-warming pipeline is communicated with the steam circulation pipeline and is positioned at the downstream of the last steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline;
the inverted heating pipeline is sequentially provided with a liquid storage unit, a circulating pump, a molten salt heat exchange unit and a steam energy storage unit; a liquid level meter and a first thermometer are arranged on the liquid storage unit; the molten salt input end of the molten salt heat exchange unit is provided with a temperature adjusting pump and is communicated with a molten salt storage tank of an external solar power generation system; a pressure gauge is arranged on the steam energy storage unit;
the second thermometer is arranged at the molten salt outlet temperature of the preheater of the external solar power generation system;
and the control part is in signal connection with the liquid level meter, the first thermometer, the pressure gauge, the second thermometer, the temperature adjusting pump and the circulating pump respectively and is used for controlling the temperature adjusting pump and the circulating pump according to the parameters of the liquid level meter, the first thermometer, the pressure gauge and the second thermometer.
The anti-freezing system for the molten salt heat exchange equipment and the pipeline comprises a back heating pipeline, a water conveying pipeline, a steam input pipeline and a steam output pipeline, wherein the back heating pipeline comprises a water return pipeline, a water conveying pipeline, a steam output pipeline and a water return pipeline;
the input end of the water return pipeline is communicated with the steam circulation pipeline and is positioned at the downstream of the last steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline; the input end of the water return pipeline is communicated with the input end of the liquid storage unit;
two ends of the water conveying pipeline are respectively communicated with the output end of the liquid storage unit and the liquid input end of the molten salt heat exchange unit;
two ends of the steam input pipeline are respectively communicated with a steam output end of the molten salt heat exchange unit and a steam input end of the steam energy storage unit;
the input end of the steam output pipeline is communicated with the steam output end of the steam energy storage unit; the output end of the steam output pipeline is communicated with the steam circulation pipeline and is positioned at the upstream of the first steam molten salt heat exchange device in the medium flowing direction on the steam circulation pipeline.
According to the anti-freezing system for the molten salt heat exchange equipment and the pipeline, the steam circulation pipeline comprises the superheater branch and the reheater branch which are independent of each other;
the water return pipeline is a first water return pipe and a second water return pipe; two ends of the first water return pipe are respectively communicated with the output end of the superheater branch and the input end of the liquid storage unit, and two ends of the second water return pipe are respectively communicated with the output end of the reheater branch and the input end of the liquid storage unit;
and the first water return pipe and the second water return pipe are respectively provided with a first water return valve and a second water return valve.
According to the anti-freezing system for the molten salt heat exchange equipment and the pipeline, the steam input end and the steam output end of the steam energy storage unit are steam connectors located on the steam energy storage unit;
the steam input pipeline comprises a first steam section and a second steam section which are sequentially connected, the head end of the first steam section is communicated with the steam output end of the molten salt heat exchange unit, and the tail end of the second steam section is communicated with the steam connecting port;
the steam output pipeline comprises the second steam section, a third steam section, a first steam branch and a second steam branch; the head end of the third steam section is communicated with the head end of the second steam section; two ends of the first steam branch are respectively communicated with the tail end of the third steam section and the input end of the superheater branch; two ends of the first steam branch are respectively communicated with the tail end of the third steam section and the input end of the reheater branch;
the first steam section is provided with a first steam valve, the second steam section is provided with a second steam valve, the first steam branch is provided with a superheated steam valve, and the second steam branch is provided with a reheated steam valve.
According to the anti-freezing system for the molten salt heat exchange equipment and the pipeline, the superheater branch is provided with the superheater, the steam drum, the evaporator and the preheater in sequence;
the second thermometer is arranged at the molten salt outlet of the preheater.
The invention discloses an anti-freezing system for molten salt heat exchange equipment and pipelines, wherein a molten salt heat exchange unit comprises an auxiliary heat exchanger, a first molten salt pipeline and a second molten salt pipeline;
the input end of the first molten salt pipeline is communicated with the molten salt storage tank, the output end of the first molten salt pipeline is communicated with the molten salt inlet of the auxiliary heat exchanger, and the temperature regulating pump is arranged on the first molten salt pipeline;
the input end of the second molten salt pipeline is communicated with the molten salt outlet of the auxiliary heat exchanger, and the output end of the second molten salt pipeline is communicated with the corresponding molten salt storage tank.
The anti-freezing system for the molten salt heat exchange equipment and the pipeline further comprises a third molten salt pipeline;
a first molten salt valve is arranged on the first molten salt pipeline and is positioned at the downstream of the temperature regulating pump;
the input end of the third molten salt pipeline is communicated with the first molten salt pipeline and is positioned between the temperature regulating pump and the first molten salt valve; and the output end of the third molten salt pipeline is connected to a salt inlet main pipe of an external solar power generation system.
The invention relates to an anti-freezing system for molten salt heat exchange equipment and pipelines, which also comprises a drain pipeline;
the input end of the drain pipeline is communicated with the bottom of the steam energy storage unit, the output end of the water conveying pipeline is communicated with the input end of the liquid storage unit, and a drain valve is arranged on the drain pipeline.
The control method is applied to any one of the anti-freezing systems for the molten salt heat exchange equipment and the pipeline, and comprises the following steps:
when the external solar power generation system reduces the load: starting the temperature adjusting pump and the circulating pump, and storing energy to preset energy storage pressure by the steam energy storage unit;
when the external solar power generation system is shut down: monitoring parameters of a second thermometer, and if the parameters are lower than preset parameters, starting a back-warming pipeline to carry out heat tracing on steam molten salt heat exchange equipment on a steam circulation pipeline;
and monitoring parameters of the liquid level meter, the first thermometer and the pressure gauge, and starting the temperature regulating pump and the circulating pump if the parameters are lower than preset parameters.
Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:
according to the embodiment of the invention, the reverse heating pipeline is arranged on the conventional steam circulating pipeline, the liquid storage unit, the circulating pump, the molten salt heat exchange unit and the steam energy storage unit are sequentially arranged on the reverse heating pipeline, circulating liquid in the liquid storage unit enters the molten salt heat exchange unit under the action of the circulating pump, and exchanges heat with molten salt introduced from an external molten salt storage tank to form heat tracing steam which is stored in the steam energy storage unit. When the solar power generation system is shut down, parameters of equipment such as a liquid level meter, a first thermometer, a pressure gauge and a second thermometer can be monitored through the solar power generation system, when heat tracing is needed, heat tracing steam in the steam energy storage unit is led out to an existing steam circulation pipeline, steam molten salt heat exchange equipment on the steam circulation pipeline receives the heat tracing steam, heat tracing is conducted on molten salt through the heat exchange capacity of the steam molten salt heat exchange equipment, and therefore the molten salt is maintained above the condensation temperature. The consumed residual heat energy is only residual heat energy in the external molten salt storage tank, power consumption is not needed, the operation is stable and reliable, the fault rate is low, the design life is the same as that of a pressure pipeline and a container, and the problems of large energy consumption and low reliability of the conventional electric tracing system are solved.
Drawings
FIG. 1 is a schematic diagram of the freeze protection system for molten salt heat exchange equipment and piping of the present invention.
Description of reference numerals: 1: a liquid storage unit; 2: a circulation pump; 3: an auxiliary heat exchanger; 4: a steam energy storage unit; 5: a liquid level meter; 6: a first thermometer; 7: a tempering pump; 8: a pressure gauge; 9: a second thermometer; 10: a first return pipe; 11: a second water return pipe; 12: a water delivery pipeline; 13: a first steam section; 14: a second steam section; 15: a third steam stage; 16: a first steam branch; 17: a second steam branch; 18: a first water return valve; 19: a second water return valve; 20: a first steam valve; 21: a second steam valve; 22: a superheated steam valve; 23: a reheat steam valve; 24: a first molten salt pipeline; 25: a second molten salt pipeline; 26: a third molten salt conduit; 27: a first molten salt valve; 28: a second molten salt valve; 29: a molten salt storage tank; 30: a salt inlet main pipe; 31: a superheater; 32: a steam drum; 33: an evaporator; 34: a preheater; 35: a reheater.
Detailed Description
The anti-freezing system and the control method for the molten salt heat exchange equipment and the pipeline provided by the invention are further described in detail with reference to the attached drawings and specific embodiments. Advantages and features of the present invention will become apparent from the following description and from the claims.
Referring to FIG. 1, in one embodiment, an antifreeze system for molten salt heat exchange equipment and piping for providing back-warmed steam to a steam circulation line of an external solar power system may include the back-warmed line, a second thermometer 9, and a control section.
The steam output end of the back-warming pipeline is communicated with the steam circulation pipeline and is positioned at the upstream of the first steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline. And the water return end of the back-warming pipeline is communicated with the steam circulation pipeline and is positioned at the downstream of the last steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline.
Wherein, be equipped with stock solution unit 1, circulating pump 2, fused salt heat transfer unit and steam energy storage unit 4 on the warm pipeline of falling in proper order. The liquid storage unit 1 is provided with a liquid level meter 5 and a first thermometer 6. The molten salt input end of the molten salt heat exchange unit is provided with a temperature regulating pump 7, and the molten salt input end is communicated with a molten salt storage tank 29 of an external solar power generation system. The steam energy storage unit 4 is provided with a pressure gauge 8.
The second thermometer 9 is the molten salt outlet temperature of the preheater 34 provided in the external solar power generation system.
The control part is respectively connected with the liquid level meter 5, the first thermometer 6, the pressure gauge 8, the second thermometer 9, the temperature adjusting pump 7 and the circulating pump 2 in a signal mode and used for controlling the temperature adjusting pump 7 and the circulating pump 2 according to parameters of the liquid level meter 5, the first thermometer 6, the pressure gauge 8 and the second thermometer 9.
This embodiment is through setting up the warm pipeline of falling on current steam circulation pipeline to set gradually stock solution unit 1, circulating pump 2, fused salt heat transfer unit and steam energy storage unit 4 on the warm pipeline of falling, the circulating liquid in the stock solution unit 1 gets into the fused salt heat transfer unit under circulating pump 2's effect, forms heat tracing steam with the fused salt heat transfer that 29 departments of outside fused salt storage tanks let in, and stores to steam energy storage unit 4. When solar power system shut down, the accessible monitors the parameter of equipment such as level gauge 5, first thermometer 6, manometer 8, second thermometer 9, when needs heat tracing, draws forth the heat tracing steam in the steam energy storage unit 4 to current steam circulation pipeline, and steam fused salt heat transfer equipment on the steam circulation pipeline receives heat tracing steam, utilizes the heat exchange capacity of steam fused salt heat transfer equipment itself to carry out the heat tracing to the fused salt to maintain the fused salt above the condensing temperature. The consumed residual heat energy is only residual heat energy in the external molten salt storage tank 29, power consumption is not needed, the operation is stable and reliable, the fault rate is low, the design life is the same as that of a pressure pipeline and a container, and the problems of large energy consumption and low reliability of the conventional electric tracing system are solved.
The following further explains the specific structure of the antifreeze system for molten salt heat exchange equipment and pipelines in this embodiment, taking the circulating liquid as water as an example:
in this embodiment, the back-warming pipeline may specifically include a water return pipeline, a water conveying pipeline 12, a steam input pipeline, and a steam output pipeline.
The input end of the water return pipeline is communicated with the steam circulation pipeline and is positioned at the downstream of the last steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline. The input end of the water return pipeline is communicated with the input end of the liquid storage unit 1.
The two ends of the water conveying pipeline 12 are respectively communicated with the output end of the liquid storage unit 1 and the liquid input end of the fused salt heat exchange unit, and the circulating pump 2 is arranged on the water conveying pipeline 12 and used for pumping water into the fused salt heat exchange unit for heat exchange.
Two ends of the steam input pipeline are respectively communicated with the steam output end of the fused salt heat exchange unit and the steam input end of the steam energy storage unit 4. The input end of the steam output pipeline is communicated with the steam output end of the steam energy storage unit 4. The output end of the steam output pipeline is communicated with the steam circulation pipeline and is positioned at the upstream of the first steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline.
Further, many of the existing steam circuits are not just a single circuit, but many have certain branches within a large cycle frame to improve efficiency, for example, the steam circuit may include separate superheater 31 branch and reheater 35 branch.
In this case, the return line may be divided into a first return pipe 10 and a second return pipe 11. The two ends of the first water return pipe 10 are respectively communicated with the output end of the superheater 31 branch and the input end of the liquid storage unit 1, and the two ends of the second water return pipe 11 are respectively communicated with the output end of the reheater 35 branch and the input end of the liquid storage unit 1.
Wherein, a first water return valve 18 and a second water return valve 19 are respectively arranged on the first water return pipe 10 and the second water return pipe 11. The on-off of different pipelines can be realized through the opening and closing of the two water return valves.
Likewise, the steam supply line and the steam discharge line can also be adjusted. The steam input and the steam output of the steam energy storage unit 4 may be provided as a steam connection port on the steam energy storage unit 4.
The steam input pipeline comprises a first steam section 13 and a second steam section 14 which are connected in sequence, the head end of the first steam section 13 is communicated with the steam output end of the molten salt heat exchange unit, and the tail end of the second steam section 14 is communicated with the steam connecting port.
The steam outlet line may then comprise the second steam section 14, the third steam section 15, the first steam branch 16 and the second steam branch 17 described above. The head end of the third steam stage 15 is in communication with the head end of the second steam stage 14. The two ends of the first steam branch 16 are respectively communicated with the tail end of the third steam section 15 and the input end of the superheater 31 branch. Both ends of the first steam branch 16 are respectively communicated with the tail end of the third steam section 15 and the input end of the reheater 35 branch.
The first steam section 13 is provided with a first steam valve 20, the second steam section 14 is provided with a second steam valve 21, the first steam branch 16 is provided with a superheated steam valve 22, and the second steam branch 17 is provided with a reheated steam valve 23. Wherein, the second steam valve can be a switching valve.
When the steam needs to be stored, the first steam valve 20 and the second steam valve 21 are opened, and the superheated steam valve 22 and the reheat steam valve 23 are closed; when the steam to be generated is directly subjected to heat tracing, the first steam valve 20 and the superheated steam valve 22 and/or the reheat steam valve 23 are opened, and the second steam valve 21 is closed; when only the extraction of steam is required, the second steam valve 21 and the superheated steam valve 22 and/or the reheat steam valve 23 are opened, and the first steam valve 20 is closed.
Specifically, the superheater 31 branch can be provided with a superheater 31, a steam drum 32, an evaporator 33 and a preheater 34 in sequence. The second thermometer 9 is provided at the molten salt outlet of the preheater 34, and detects the temperature of the molten salt at the molten salt outlet.
In this embodiment, the molten salt heat exchange unit may include the auxiliary heat exchanger 3, the first molten salt pipeline 24, and the second molten salt pipeline 25.
The input end of the first molten salt pipeline 24 is communicated with the molten salt storage tank 29 (specifically, the cold salt storage tank), the output end of the first molten salt pipeline 24 is communicated with the molten salt inlet of the auxiliary heat exchanger 3, and the first molten salt pipeline 24 is provided with the temperature regulating pump 7. The input end of the second molten salt pipeline 25 is communicated with the molten salt outlet of the auxiliary heat exchanger 3, and the output end of the second molten salt pipeline 25 is communicated with the corresponding molten salt storage tank 29.
Further, the antifreeze system may also include a third molten salt line 26. The first molten salt pipeline 24 is provided with a first molten salt valve 27, the first molten salt valve 27 is located at the downstream of the temperature adjusting pump 7, and the first molten salt valve 27 can be used for adjusting the flow of molten salt.
The input end of the third molten salt pipeline 26 is communicated with the first molten salt pipeline 24 and is positioned between the temperature regulating pump 7 and the first molten salt valve 27, the output end of the third molten salt pipeline 26 is connected to a salt inlet main pipe 30 of an external solar power generation system, and the third molten salt pipeline 26 can be provided with a second molten salt valve 28.
When the temperature of the second thermometer 9 is lower than the preset value, the temperature regulating pump 7 can be started and the second molten salt valve 28 can be opened, molten salt can be slowly pushed through the main path of the molten salt system, and freezing is prevented.
In this embodiment, the anti-freeze system may further include a drain line. The input end of the drain pipeline is communicated with the bottom of the steam energy storage unit 4, the output end of the water conveying pipeline 12 is communicated with the input end of the liquid storage unit 1, and a drain valve is arranged on the drain pipeline.
In summary, the embodiment utilizes two modes of the steam reverse heating heat tracing and the molten salt continuous flowing maintenance to ensure that the molten salt is more energy-saving and more reliable in freezing prevention
The main factors for solidification of the molten salt are: (1) The heat dissipation capacity of the outer surface of the equipment is large in the shutdown state, and the electric tracing faults occur. (2) The lower feed water temperature when the unit is started leads to the solidification of the shell-side molten salt of the preheater 34.
The basic workflow of the anti-freezing system is as follows: saturated steam in the steam energy accumulator flows through the superheater 31/reheater 35, the steam drum 32, the evaporator 33 and the preheater 34 step by means of pressure difference, condensed water for completing heat exchange is connected into the liquid storage unit 1 and is pumped into the auxiliary heat exchanger 3 through the circulating pump 2, a part of generated steam enters the steam energy storage unit 4 for storage, and a part of generated steam continuously supplies steam to steam molten salt heat exchange equipment in a steam circulating pipeline.
The use of the antifreeze system is as follows: 1. and continuously heating the heat exchanger equipment pipes, plates, the shell and the internal reserved molten salt in the shutdown state, wherein the temperature of the outer surface of the heat exchanger is not lower than the solidification temperature of the molten salt. Meanwhile, the temperature interlocking temperature regulating pump 7 of the wall of the molten salt outlet pipe of the preheater 34 is started, the flow of the cold molten salt is controlled by the regulating valve, the molten salt is pushed to slowly flow in the heat exchange equipment and the pipeline, and the molten salt close to the solidification temperature in the system is sent back to the cold salt tank to replace the molten salt with higher temperature; 2. the method comprises the steps of preheating the tubes, plates, the shell and the molten salt reserved in the heat exchanger before starting, carrying out operations such as feeding water to the boiler, starting the circulating temperature rise equipment by the steam drum 32, feeding salt into the equipment and the pipeline and the like after ensuring that the temperature of the outer surface of the heat exchanger is not lower than the solidification temperature of the molten salt, and shortening the starting time.
The working pressure of the steam energy storage unit 4 can be set to be 5MPa, and the heat tracing steam pressure from the inlet of the superheater 31 to the outlet of the preheater 34 is always maintained above the saturated steam pressure with the molten salt solidification temperature as the saturation temperature in the working process. The stored effective heat supply amount can meet the requirement of maintaining the surface temperature of the heat exchange equipment in the first warm-state starting and stopping time and also can meet the preheating steam amount of the first cold-state starting of the steam generation system.
The embodiment utilizes the principle that the temperature of the working medium is not changed in a saturated steam state, a steam-water two-phase mixture and a saturated water state, combines the characteristic of large phase-change heat exchange quantity, and realizes a novel heat tracing system through the circulating storage and release of energy. Its main advantage is as follows: 1. the operation is stable and reliable, the failure rate is low, and the design life is the same as that of a pressure pipeline and a container; 2. the embodiment and the power generation steam generation system process share part of temperature and pressure measuring points, so that a control system is simplified; 3. the steam energy storage unit 4 has the effects of pressure stabilization and energy storage, can be used as a heat tracing steam source and can be used for supplying heating and process steam, the operation is very flexible, and the temperature fluctuation interval of the heat exchange equipment is reduced. 4. The unit can warm up in advance to indirect heating equipment before starting, compares and starts that circulation electric heater is more nimble, shortens the activation time.
Example two
The embodiment provides a control method, which is applied to the antifreeze system for the molten salt heat exchange equipment and the pipeline in the first embodiment, and comprises the following steps:
when the external solar power generation system reduces the load: the temperature adjusting pump 7 and the circulating pump 2 are started to preheat and supplement steam for the steam energy storage unit 4, the steam energy storage unit 4 stores energy to a preset energy storage pressure (6 MPa), and the second steam valve 21 is closed while the machine is stopped.
When the external solar power generation system is shut down: when the temperature of the second thermometer 9 is lower than 260 ℃ or the temperature of the steam-water remote thermometer is lower than 250 ℃, the second steam valve 21 is started, steam in the steam energy storage unit 4 is divided into two paths, one path of steam enters the superheater 31, the steam drum 32, the evaporator 33 and the preheater 34, back heating is realized through a main steam pipeline, an ascending pipe, a descending pipe, a water supply pipeline and the like, the isolation valve of the water supply inlet of the preheater 34 is stopped and closed at the same time, the first water return pipe 10 is led out between the isolation valve and the preheater 34 and is connected into the liquid storage unit 1, and the first water return valve 18 is started.
The other path enters a reheater 35 through a branch of a superheated and reheated steam pipeline, a steam inlet and outlet isolation valve of the reheater 35 is closed when the machine is stopped, a second water return pipe 11 is arranged in front of a steam inlet isolation valve of the reheater 35, a second water return valve 19 is opened, and return water enters the liquid storage unit 1.
Monitoring the steam pocket 32 and the pressure gauge 8, when the indication value of the pressure gauge 8 is lower than 3.5MPa, and the liquid level meter 5 displays that the liquid level of the liquid storage unit 1 is in a normal liquid level, starting the circulating pump 2 and the temperature adjusting pump 7 at the moment, stabilizing the liquid level meter 5, controlling the pressure of the steam pocket 32 and the pressure gauge 8 to be more than 3.5MPa, and simultaneously monitoring the temperature of a medium in the liquid storage unit 1 to be more than 250 ℃.
When the temperature of the molten salt outlet at the second thermometer 9 is lower than 260 ℃, the temperature-adjusting pump 7 and the second molten salt valve 28 are started, and molten salt is slowly pushed through the main path of the molten salt system to prevent freezing.
By monitoring the liquid level meter 5, when the liquid level is at a high liquid level, the interlocking circulating pump 2 is started and the temperature regulating pump 7 is started, and simultaneously the first steam valve 20 and the second steam valve 21 are interlockingly regulated by remote pressure of the pressure gauge 8; when the liquid level of the liquid storage unit 1 returns to be below the low liquid level, the steam energy storage process is ended, the circulating pump 2 and the first steam valve 20 are closed, and the second steam valve 21 is operated to change the steam process into the flow direction of the steam energy storage unit 4 towards the superheater 31 and the reheater 35.
The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments. Even if various changes are made to the present invention, they are still within the scope of the present invention provided that they fall within the scope of the claims of the present invention and their equivalents.
Claims (9)
1. An anti-freeze system for molten salt heat exchange equipment and pipes, for providing back-warmed steam to a steam circulation line of an external solar power generation system, comprising:
the steam output end of the back-warming pipeline is communicated with the steam circulation pipeline and is positioned at the upstream of the first steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline; the water return end of the back-warming pipeline is communicated with the steam circulation pipeline and is positioned at the downstream of the tail steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline;
the inverted heating pipeline is sequentially provided with a liquid storage unit, a circulating pump, a molten salt heat exchange unit and a steam energy storage unit; a liquid level meter and a first thermometer are arranged on the liquid storage unit; the molten salt input end of the molten salt heat exchange unit is provided with a temperature adjusting pump and is communicated with a molten salt storage tank of an external solar power generation system; a pressure gauge is arranged on the steam energy storage unit;
the second thermometer is arranged at the molten salt outlet temperature of the preheater of the external solar power generation system;
and the control part is in signal connection with the liquid level meter, the first thermometer, the pressure gauge, the second thermometer, the temperature regulating pump and the circulating pump respectively, and is used for controlling the temperature regulating pump and the circulating pump according to the parameters of the liquid level meter, the first thermometer, the pressure gauge and the second thermometer.
2. The antifreeze system for molten salt heat exchange equipment and pipes of claim 1, wherein the back-warming pipeline comprises a water return pipeline, a water delivery pipeline, a steam input pipeline, and a steam output pipeline;
the input end of the water return pipeline is communicated with the steam circulation pipeline and is positioned at the downstream of the last steam molten salt heat exchange equipment in the medium flowing direction on the steam circulation pipeline; the input end of the water return pipeline is communicated with the input end of the liquid storage unit;
two ends of the water conveying pipeline are respectively communicated with the output end of the liquid storage unit and the liquid input end of the fused salt heat exchange unit;
two ends of the steam input pipeline are respectively communicated with a steam output end of the molten salt heat exchange unit and a steam input end of the steam energy storage unit;
the input end of the steam output pipeline is communicated with the steam output end of the steam energy storage unit; the output end of the steam output pipeline is communicated with the steam circulation pipeline and is positioned at the upstream of the first steam molten salt heat exchange device in the medium flowing direction on the steam circulation pipeline.
3. The antifreeze system for molten salt heat exchange equipment and piping according to claim 2, wherein the steam circulation line comprises a superheater branch and a reheater branch that are independent of each other;
the water return pipeline is a first water return pipe and a second water return pipe; two ends of the first water return pipe are respectively communicated with the output end of the superheater branch and the input end of the liquid storage unit, and two ends of the second water return pipe are respectively communicated with the output end of the reheater branch and the input end of the liquid storage unit;
and the first water return pipe and the second water return pipe are respectively provided with a first water return valve and a second water return valve.
4. The antifreeze system for molten salt heat exchange equipment and piping of claim 3, wherein the steam input and the steam output of the steam energy storage unit are steam connection ports on the steam energy storage unit;
the steam input pipeline comprises a first steam section and a second steam section which are sequentially connected, the head end of the first steam section is communicated with the steam output end of the molten salt heat exchange unit, and the tail end of the second steam section is communicated with the steam connecting port;
the steam output pipeline comprises the second steam section, a third steam section, a first steam branch and a second steam branch; the head end of the third steam section is communicated with the head end of the second steam section; two ends of the first steam branch are respectively communicated with the tail end of the third steam section and the input end of the superheater branch; two ends of the first steam branch are respectively communicated with the tail end of the third steam section and the input end of the reheater branch;
the first steam section is provided with a first steam valve, the second steam section is provided with a second steam valve, the first steam branch is provided with a superheated steam valve, and the second steam branch is provided with a reheated steam valve.
5. The antifreeze system for molten salt heat exchange equipment and pipelines according to claim 3, wherein the superheater branch is provided with a superheater, a steam drum, an evaporator and a preheater in sequence;
the second thermometer is arranged at the molten salt outlet of the preheater.
6. The antifreeze system for molten salt heat exchange equipment and piping of claim 1 wherein the molten salt heat exchange unit comprises an auxiliary heat exchanger, a first molten salt conduit, a second molten salt conduit;
the input end of the first molten salt pipeline is communicated with the molten salt storage tank, the output end of the first molten salt pipeline is communicated with the molten salt inlet of the auxiliary heat exchanger, and the temperature regulating pump is arranged on the first molten salt pipeline;
the input end of the second molten salt pipeline is communicated with the molten salt outlet of the auxiliary heat exchanger, and the output end of the second molten salt pipeline is communicated with the corresponding molten salt storage tank.
7. The antifreeze system for molten salt heat exchange equipment and piping according to claim 6, further comprising a third molten salt conduit;
a first molten salt valve is arranged on the first molten salt pipeline and is positioned at the downstream of the temperature adjusting pump;
the input end of the third molten salt pipeline is communicated with the first molten salt pipeline and is positioned between the temperature regulating pump and the first molten salt valve; and the output end of the third molten salt pipeline is connected to a salt inlet main pipe of an external solar power generation system.
8. The antifreeze system for molten salt heat exchange equipment and piping of claim 1, further comprising a hydrophobic conduit;
the input end of the drain pipeline is communicated with the bottom of the steam energy storage unit, the output end of the water conveying pipeline is communicated with the input end of the liquid storage unit, and a drain valve is arranged on the drain pipeline.
9. A control method, applied to the antifreeze system for molten salt heat exchange equipment and pipes according to any one of claims 1 to 8, is as follows:
when the external solar power generation system reduces the load: starting the temperature regulating pump and the circulating pump, and storing energy to preset energy storage pressure by the steam energy storage unit;
when the external solar power generation system is shut down: monitoring parameters of a second thermometer, and if the parameters are lower than preset parameters, starting a back-warming pipeline to carry out heat tracing on steam molten salt heat exchange equipment on a steam circulation pipeline;
and monitoring parameters of the liquid level meter, the first thermometer and the pressure gauge, and starting the temperature regulating pump and the circulating pump if the parameters are lower than preset parameters.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211027818.3A CN115342673A (en) | 2022-08-25 | 2022-08-25 | Anti-freezing system for molten salt heat exchange equipment and pipeline and control method |
| CN202310352557.0A CN116428900A (en) | 2022-08-25 | 2023-04-04 | Antifreezing system for molten salt heat exchange equipment and pipeline and control method |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211027818.3A CN115342673A (en) | 2022-08-25 | 2022-08-25 | Anti-freezing system for molten salt heat exchange equipment and pipeline and control method |
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| CN115342673A true CN115342673A (en) | 2022-11-15 |
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| CN202211027818.3A Pending CN115342673A (en) | 2022-08-25 | 2022-08-25 | Anti-freezing system for molten salt heat exchange equipment and pipeline and control method |
| CN202310352557.0A Pending CN116428900A (en) | 2022-08-25 | 2023-04-04 | Antifreezing system for molten salt heat exchange equipment and pipeline and control method |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202310352557.0A Pending CN116428900A (en) | 2022-08-25 | 2023-04-04 | Antifreezing system for molten salt heat exchange equipment and pipeline and control method |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116718059A (en) * | 2023-08-07 | 2023-09-08 | 山西中能天胜科技有限公司 | Power station peak shaving system and method based on high-capacity high-temperature molten salt energy storage |
-
2022
- 2022-08-25 CN CN202211027818.3A patent/CN115342673A/en active Pending
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2023
- 2023-04-04 CN CN202310352557.0A patent/CN116428900A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116718059A (en) * | 2023-08-07 | 2023-09-08 | 山西中能天胜科技有限公司 | Power station peak shaving system and method based on high-capacity high-temperature molten salt energy storage |
| CN116718059B (en) * | 2023-08-07 | 2023-10-27 | 山西中能天胜科技有限公司 | Power station peak shaving system and method based on high-capacity high-temperature molten salt energy storage |
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| Publication number | Publication date |
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| CN116428900A (en) | 2023-07-14 |
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Application publication date: 20221115 |