Thermoelectric decoupling control system for full-energy heat storage of coupling steam energy accumulator

Abstract

The invention provides a thermoelectricity decoupling control system coupled with steam energy accumulator total energy heat storage, and relates to the technical field of steam power cycle thermoelectricity decoupling control, the thermoelectricity decoupling control system comprises a heat storage heat exchanger, a fused salt heat storage system, a steam energy accumulator heat storage system and a gas supply pipeline, and the heat storage heat exchanger is internally provided with a heat supply medium passage and a heat storage medium passage; a medium inlet of the heat supply medium passage is communicated with a steam source; the fused salt heat storage system comprises a low-temperature fused salt tank and a high-temperature fused salt tank, and the low-temperature fused salt tank and the high-temperature fused salt tank communicate with a medium inlet and a medium outlet in the heat storage medium channel correspondingly. The steam energy accumulator heat storage system comprises a steam energy accumulator, and the air inlet end of the steam energy accumulator communicates with a medium outlet of the heat supply medium channel. The air inlet end of the air supply pipeline is communicated with a pipeline between the heat supply medium passage and the steam energy accumulator; high-grade sensible heat, low-grade sensible heat and all latent heat of steam heat energy can be fully utilized, the energy utilization rate is increased, regulation and control of the heat storage system are more flexible, and meanwhile economic benefits are increased.

Description

Technical Field

[0001] The invention relates to the technical field of thermoelectric decoupling control of steam power cycles, and in particular to a thermoelectric decoupling control system coupled with a steam accumulator for full energy heat storage. Background Art

[0002] In today's energy sector, with the rapid development of renewable energy and the diversification of energy supply and demand, the flexibility and stability of energy systems have become crucial considerations. On the one hand, energy demand varies significantly in different periods and seasons. When dealing with changes in energy supply and demand, traditional steam power cycle systems often have problems with the flexibility to adjust heat and electricity, which limits their efficient operation in a complex energy environment. On the other hand, the intermittent and instability of renewable energy also poses a huge challenge to energy supply.

[0003] In order to achieve thermoelectric decoupling of steam power cycle systems and improve energy efficiency and system flexibility, heat storage technology has gradually become the focus of current energy research. Reasonable and efficient heat storage technology can effectively regulate the conversion and balance between thermal energy and electrical energy, and adapt to the dynamic changes in a wider range of energy demand. However, the existing heat storage process control methods are not perfect, and the heat storage efficiency is low. Moreover, in the face of complex, changeable and unpredictable energy supply and demand conditions, it is difficult to achieve flexible regulation and control, and it is impossible to maximize the utilization of energy, which in turn restricts the widespread application and further development of steam power cycle systems in the energy field to a certain extent.

[0004] Therefore, it is urgent to effectively solve the problems of low heat storage efficiency and inflexible regulation in the thermoelectric decoupling process through innovative control strategies and advanced technical means, and to achieve efficient control of the heat storage process. Summary of the invention

[0005] The purpose of the present invention is to provide a thermoelectric decoupling control system coupled with a steam accumulator for full energy heat storage to solve the problems existing in the prior art. It can fully utilize the high-grade sensible heat, low-grade sensible heat and all latent heat of steam thermal energy to improve energy utilization, and make the regulation of the heat storage system more flexible, while improving economic benefits.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] A thermoelectric decoupling control system coupled with a steam accumulator for full energy heat storage, comprising a heat storage heat exchanger, a molten salt heat storage system, a steam accumulator heat storage system and an air supply pipeline, wherein the heat storage heat exchanger is provided with a heat supply medium passage and a heat storage medium passage for circulating a heat exchange medium, and a medium inlet of the heat supply medium passage is connected to a steam source; the molten salt heat storage system comprises a low-temperature molten salt tank and a high-temperature molten salt tank, and the low-temperature molten salt tank and the high-temperature molten salt tank are respectively connected to a medium inlet and a medium outlet in the heat storage medium passage; the steam accumulator heat storage system comprises a steam accumulator, and an air inlet end of the steam accumulator is connected to a medium outlet of the heat supply medium passage; and an air inlet end of the air supply pipeline is connected to a pipeline between the heat supply medium passage and the steam accumulator.

[0008] As an embodiment, a first desuperheater is further provided between the steam source and the heat supply medium passage, the first desuperheater is connected to a cold medium source, and the cold medium source provides cold medium to reduce the temperature and pressure of the steam.

[0009] As an implementation mode, along the supply direction of steam, a first shut-off valve, a hydraulic fast-closing valve and a flow meter are sequentially arranged between the steam source and the first desuperheater.

[0010] As one embodiment, a first regulating valve group for regulating the flow rate of cold medium supplied by the cold medium source is arranged between the cold medium source and the first cooler, and the first regulating valve group includes a second shut-off valve, a first regulating valve and a third shut-off valve arranged in sequence along the cold medium supply direction.

[0011] As an embodiment, a second regulating valve group for regulating the gas supply flow is arranged on the gas supply pipeline; the second regulating valve group includes a fifth shut-off valve, a second regulating valve and a fourth shut-off valve arranged in sequence along the gas supply direction.

[0012] As an embodiment, a second desuperheater is further provided between the steam accumulator and the heat supply medium passage, and the second desuperheater is connected to a cold medium source, and the cold medium source provides cold medium to reduce the temperature and pressure of the steam.

[0013] As one embodiment, a third regulating valve group is arranged between the cold medium source and the second cooler for regulating the flow rate of cold medium supplied by the cold medium source, and the third regulating valve group includes a sixth shut-off valve, a third regulating valve and a seventh shut-off valve arranged in sequence along the cold medium supply direction.

[0014] As an embodiment, a molten salt pump for providing power for the flow of molten salt is provided between the low-temperature molten salt tank and the heat supply medium passage.

[0015] As an implementation manner, an eighth shutoff valve is provided at the air inlet of the steam accumulator, and a check valve is provided in front of the eighth shutoff valve along the steam supply direction.

[0016] As an implementation mode, the steam accumulator is connected to a replenishment water source via a replenishment water pump.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] The present invention can make full use of high-grade sensible heat, low-grade sensible heat and all latent heat of steam thermal energy and improve energy utilization rate by providing a molten salt heat storage system and a steam accumulator heat storage system; moreover, after the steam accumulator is fully filled with thermal energy before the high-temperature molten salt tank, the heating pipeline provided at the medium outlet of the heating medium passage can be used for industrial gas supply, so that the regulation and control of the heat storage system is more flexible, which is conducive to realizing resource redistribution, optimizing the regional energy structure and improving the comprehensive efficiency of the energy system; at the same time, the additional industrial steam supply can increase the source of income, reduce production costs, and enhance economic benefits and market competitiveness.

[0019] Other technical solutions in the present invention also have the following technical effects:

[0020] 1. The present invention provides a first desuperheater between the steam source and the heating medium passage, so as to maintain the steam about to enter the heating medium passage within a certain temperature range by spraying cold water, thereby reducing the loss of the heat storage heat exchanger, ensuring that the heat storage heat exchanger operates under stable and safe conditions, and at the same time reducing the grade of the material used in the pipeline, reducing the investment and operation and maintenance costs, and improving the reliability and safety of the overall operation of the pipeline system.

[0021] 2. The present invention is provided with a second desuperheater between the steam accumulator and the heat supply medium passage, which can reduce the temperature of the steam in the second desuperheater by spraying, so that the temperature of the steam entering the steam accumulator reaches the set temperature of the air inlet end of the steam accumulator, which can ensure that the steam accumulator operates under safe and stable working conditions, protect the safety of the steam pipeline after the heat storage heat exchanger, and further reduce the material grade of the pipeline behind it, thereby reducing the cost of pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1It is a schematic structural diagram of a thermoelectric decoupling control system coupled with a steam accumulator for full energy heat storage in one embodiment of the present invention;

[0024] Description of reference numerals:

[0025] 1. Steam supply pipeline; 2. First shut-off valve; 3. Hydraulic fast closing valve; 4. Flow meter; 5. First desuperheater; 6. Second shut-off valve; 7. First regulating valve; 8. Third shut-off valve; 9. Safety valve; 10. Heat storage heat exchanger; 11. Fourth shut-off valve; 12. Second regulating valve; 13. Fifth shut-off valve; 14. Sixth shut-off valve; 15. Third regulating valve; 16. Seventh shut-off valve; 17. Second desuperheater; 18. High-temperature molten salt tank; 19. Molten salt pump; 20. Low-temperature molten salt tank; 21. Check valve; 22. Eighth shut-off valve; 23. Steam accumulator; 24. Make-up water pump; 25. First regulating valve group; 26. Second regulating valve group; 27. Third regulating valve group; 28. Molten salt heat storage system; 29. ​​Steam accumulator heat storage system; 30. Heat storage control system. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a thermoelectric decoupling control system coupled with a steam accumulator for full energy heat storage to solve the problems existing in the prior art. It can fully utilize the high-grade sensible heat, low-grade sensible heat and all latent heat of steam thermal energy to improve energy utilization, and make the regulation of the heat storage system more flexible, while improving economic benefits.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] like Figure 1As shown, this embodiment provides a thermoelectric decoupling control system 30 coupled with full energy heat storage of a steam accumulator, comprising a heat storage heat exchanger 10, a molten salt heat storage system 28, a steam accumulator heat storage system 29 and a heat storage control system 30. A heat supply medium passage and a heat storage medium passage for circulating a heat exchange medium are provided in the heat storage heat exchanger 10, the medium inlet of the heat supply medium passage is connected to the steam source through a steam supply pipeline 1, and the medium outlet of the heat supply medium passage is connected to the air inlet end of the steam accumulator 23 in the steam accumulator heat storage system 29. The molten salt heat storage system 28 comprises a low-temperature molten salt tank 20 and a high-temperature molten salt tank 18, and the low-temperature molten salt tank 20 and the high-temperature molten salt tank 18 are respectively connected to the medium inlet and the medium outlet of the heat storage medium passage. The heat storage control system 30 comprises an air supply pipeline, and the air inlet end of the air supply pipeline is connected to the pipeline between the heat supply medium passage and the steam accumulator.

[0030] When in use, the gas supply pipeline is first in a cut-off state. The steam power cycle unit extracts steam and passes it into the steam supply pipeline 1 and into the heat medium passage in the heat storage heat exchanger 10, and the low-temperature molten salt in the low-temperature molten salt tank 20 flows into the heat storage medium passage; the low-temperature molten salt and steam exchange heat in the heat storage heat exchanger 10, and the low-temperature molten salt flows into the high-temperature molten salt tank 18 after the temperature rises to store the heat energy. In order to enhance the heat exchange efficiency between the molten salt and the steam, the flow direction of the molten salt is opposite to the flow direction of the steam. After a heat exchange, the steam enters the steam accumulator 23, and the steam accumulator 23 stores the low-grade sensible heat and all the latent heat in the medium and low temperature sections of the steam. If the steam accumulator 23 is full of heat energy before the high-temperature molten salt tank 18, the passage between the heat supply medium passage and the steam accumulator 23 is cut off, and the gas supply pipeline is connected. The steam flowing out of the medium outlet in the heat supply medium passage is directly used for industrial steam supply, which can be used for industrial production or heating.

[0031] Therefore, this embodiment can make full use of the high-grade sensible heat, low-grade sensible heat and all latent heat of steam thermal energy and improve energy utilization by setting up the molten salt heat storage system 28 and the steam accumulator heat storage system 29; and, after the steam accumulator 23 is fully filled with thermal energy before the high-temperature molten salt tank 18, the heating pipeline set at the medium outlet of the heating medium passage can be used for industrial gas supply, so that the regulation of the heat storage system is more flexible, which is conducive to realizing resource redistribution, optimizing the regional energy structure, and improving the overall efficiency of the energy system; at the same time, the additional industrial steam supply can increase the source of income, reduce production costs, and improve economic benefits and market competitiveness.

[0032] As one embodiment, a molten salt pump 19 for providing power for the flow of molten salt is provided between the low-temperature molten salt tank 20 and the heat supply medium passage.

[0033] In this embodiment, a first desuperheater 5 is further provided between the steam source and the heat supply medium passage, and the first desuperheater 5 is connected to a cold medium source, which provides a cold medium to reduce the temperature and pressure of the steam. The cold medium in this embodiment is cold water, and acts on the first desuperheater 5 in a spraying manner to reduce the temperature of the steam in the first desuperheater 5, and the steam about to enter the heat supply medium passage is maintained within a certain temperature range by controlling the amount of sprayed cold water, thereby reducing the loss of the heat storage heat exchanger 10 and ensuring that the heat storage heat exchanger 10 operates under stable and safe conditions. In addition, the material selected for the main steam pipeline of the supercritical unit is generally chrome-molybdenum steel of ASTMA335 P91 or chrome-molybdenum-vanadium steel of ASTM A335 P92. When the steam temperature is reduced, the steam pipeline material can be 12Cr1MonVG steel pipe or 12CrMonV steel pipe. Water spray cooling can effectively reduce the temperature of the extracted steam, maintain a constant temperature in the pipeline, and reduce the grade of the material used in the pipeline. That is, the steam pipelines behind the first desuperheater 5 can all use consistent, relatively low-grade material pipelines to reduce initial investment and operation and maintenance costs. When the steam pipeline uses consistent materials, on the one hand, the same pipeline materials have consistent reactions and tolerances to external influences, and are more stable in performance; on the other hand, the same pipeline materials react consistently in indicators such as stress strength and sealing, reducing local weak links caused by material differences and improving the reliability and safety of the overall operation of the pipeline system.

[0034] As an embodiment, along the steam supply direction, a first shutoff valve 2, a hydraulic quick-closing valve 3 and a flow meter 4 are sequentially arranged between the steam source and the first desuperheater 5. The flow meter 4 is used to monitor the steam flow. When the heat storage process is completed, the first shutoff valve 2 is closed, and the hydraulic quick-closing valve 3 can achieve rapid switching of the valve position in a very short time, which is used to quickly isolate the heat storage system, minimize potential risks, and enhance the overall safety of the system.

[0035] In order to control the amount of sprayed cold water, in this embodiment, a first regulating valve group 25 for adjusting the cold medium supply flow is arranged between the cold medium source and the first cooler 5. The first regulating valve group 25 includes a second shut-off valve 6, a first regulating valve 7 and a third shut-off valve 8 which are arranged in sequence along the cold medium supply direction.

[0036] As an implementation mode, a safety valve 9 is provided on the pipeline between the first desuperheater 5 and the energy storage transducer to prevent excessive pressure in the pipeline.

[0037] As an embodiment, a second regulating valve group 26 for regulating the industrial gas supply flow is provided on the gas supply pipeline; the second regulating valve group 26 includes a fifth shut-off valve 13, a second regulating valve 12 and a fourth shut-off valve 11 which are sequentially arranged along the gas supply direction.

[0038] As an embodiment, a second desuperheater 17 is also provided between the steam accumulator 23 and the heat supply medium passage, and the second desuperheater 17 is connected to a cold medium source (the cold medium source here can be the same as the cold medium source connected to the first desuperheater 5), and the cold medium source provides cold medium to reduce the temperature and pressure of the steam. The cold medium here is cold water, and acts on the second desuperheater 17 in a spraying manner to reduce the temperature of the steam in the second desuperheater 17, so that the temperature of the steam entering the steam accumulator 23 reaches the set temperature of the air inlet end of the steam accumulator 23, which can ensure that the steam accumulator 23 operates under safe and stable working conditions and protect the safety of the steam pipeline behind the second desuperheater 17. On the other hand, the selected materials for the pipeline before water spraying desuperheating are Cr-Mo alloy steel and Inconel 625 nickel-based alloy. When the steam is desuperheated by water spraying, the selected pipeline materials are usually carbon steel and Austenic 304 stainless steel. It can be seen that by setting the second desuperheater 17, the material grade of the pipeline behind it can be further reduced, reducing the cost of pipes.

[0039] It should be noted that when the high-temperature molten salt tank 18 and the steam accumulator 23 are both performing the heat storage process, the second desuperheater 17 generally does not need to spray to reduce the temperature, unless it is monitored that the temperature at the air inlet end of the steam accumulator 23 exceeds its set value. When the high-temperature molten salt tank 18 stores the heat energy before the steam accumulator 23, the molten salt pump 19 is turned off and the heat storage heat exchanger 10 also stops working accordingly. The steam temperature passing through the heat storage heat exchanger 10 is relatively high, and at this time the second desuperheater 17 starts to spray to reduce the temperature of the steam.

[0040] As one embodiment, a third regulating valve group 27 for regulating the flow rate of cold medium supplied by the cold medium source is arranged between the cold medium source and the second cooler 17. The third regulating valve group 27 includes a sixth shut-off valve 14, a third regulating valve 15 and a seventh shut-off valve 16 arranged in sequence along the cold medium supply direction.

[0041] As an embodiment, an eighth shutoff valve 22 is provided at the air inlet of the steam accumulator 23, and a check valve 21 is provided in front of the eighth shutoff valve 22 along the steam supply direction to prevent steam backflow.

[0042] As an implementation method, the steam accumulator 23 is connected to the replenishment water source through the replenishment pump 24 to achieve the liquid level and working medium quality control of the steam accumulator 23. At the same time, the steam energy storage system also has a sewage discharge mechanism for the steam accumulator 23. The sewage discharge mechanism can be a conventional device.

[0043] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0044] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A thermoelectric decoupling control system for full energy heat storage coupled with a steam accumulator, characterized in that: include: A heat storage heat exchanger, wherein the heat storage heat exchanger is provided with a heat supply medium passage and a heat storage medium passage for circulating a heat exchange medium, and a medium inlet of the heat supply medium passage is connected to a steam source; A molten salt heat storage system, the molten salt heat storage system comprising a low-temperature molten salt tank and a high-temperature molten salt tank, the low-temperature molten salt tank and the high-temperature molten salt tank are respectively connected to a medium inlet and a medium outlet in the heat storage medium passage; A steam accumulator heat storage system, the steam accumulator heat storage system comprising a steam accumulator, an air inlet end of the steam accumulator being connected to a medium outlet of the heat supply medium passage; and an air supply pipeline, wherein an air inlet end of the air supply pipeline is connected with the pipeline between the heat supply medium passage and the steam accumulator.

2. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 1 is characterized in that: A first desuperheater is further provided between the steam source and the heat supply medium passage, the first desuperheater is connected to a cold medium source, and the cold medium source provides cold medium to reduce the temperature and pressure of the steam.

3. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 2 is characterized in that: Along the supply direction of steam, a first shut-off valve, a hydraulic fast-closing valve and a flow meter are sequentially arranged between the steam source and the first desuperheater.

4. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 2 is characterized in that: A first regulating valve group for regulating the flow rate of cold medium supplied by the cold medium source is arranged between the cold medium source and the first desuperheater. The first regulating valve group includes a second shut-off valve, a first regulating valve and a third shut-off valve arranged in sequence along the cold medium supply direction.

5. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 1 is characterized in that: The gas supply pipeline is provided with a second regulating valve group for regulating the gas supply flow rate; the second regulating valve group includes a fifth shut-off valve, a second regulating valve and a fourth shut-off valve which are sequentially arranged along the gas supply direction.

6. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 1 is characterized in that: A second desuperheater is further provided between the steam accumulator and the heat supply medium passage, and the second desuperheater is connected to a cold medium source, and the cold medium source provides cold medium to reduce the temperature and pressure of steam.

7. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 6, characterized in that: A third regulating valve group for regulating the flow rate of cold medium supplied by the cold medium source is arranged between the cold medium source and the second desuperheater. The third regulating valve group includes a sixth shut-off valve, a third regulating valve and a seventh shut-off valve arranged in sequence along the cold medium supply direction.

8. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 1 is characterized in that: A molten salt pump for providing power for the flow of molten salt is arranged between the low-temperature molten salt tank and the heat supply medium passage.

9. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 1, characterized in that: An eighth shutoff valve is arranged at the air inlet of the steam accumulator, and a check valve is arranged in front of the eighth shutoff valve along the steam supply direction.

10. The thermoelectric decoupling control system for full energy heat storage of coupled steam accumulator according to claim 1, characterized in that: The steam accumulator is connected to a replenishing water source via a replenishing water pump.

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