Peaking power generation system coupled with gas holder and molten salt energy storage

Abstract

The present application relates to a kind of coupling gas holder and molten salt energy storage peak shaving power generation system, belong to the field of power generation peak shaving.It includes coal gas storage system, coal gas power generation system, peak shaving power generation system and molten salt system;The coal gas power generation system includes coal gas boiler, coal gas generator unit, steam is generated by the coal gas boiler and drives the coal gas generator unit power generation;The peak shaving power generation system includes peak shaving coal gas boiler, peak shaving steam turbine generator unit, steam is generated by the peak shaving coal gas boiler and drives the peak shaving steam turbine generator unit power generation;The molten salt system is with molten salt and water as medium and carries out energy storage, energy release to match working condition;The coal gas power generation system and the molten salt system are coupled by the coal gas boiler and the coal gas power generation system.The present application integrates gas holder, coal gas boiler, molten salt system, peak shaving coal gas boiler, to match different working conditions, realize more long-time, more flexible energy storage regulation.

Description

Technical Field

[0001] This invention belongs to the field of power generation peak shaving, and relates to a peak shaving power generation system that couples a gas holder and molten salt energy storage. Background Technology

[0002] The steel industry accounts for approximately 11% of China's total energy consumption and contributes over 60% of global carbon emissions from the steel sector. As major energy consumers, steel plants possess significant waste heat and surplus coal gas resources. The conventional practice for steel companies is to utilize recovered waste heat and surplus coal gas from production processes to generate electricity. This typically includes coal gas power generation, waste heat power generation (high-temperature, medium-temperature, and low-temperature saturated steam), TRT (Transmission Reduction Heat Transfer) waste pressure power generation, and photovoltaic power generation. The power generation system has the following areas for optimization during the production process:

[0003] 1. Mismatch between boiler and turbine loads. The minimum stable combustion load for a boiler is 30% to 50% of its rated load. The greater the deviation of the boiler from its economic load, the greater the decrease in thermal efficiency. However, the low-load operating capacity of a steam turbine is much higher than that of a boiler, and can be reduced to as low as 20% to 25%. This mismatch between boiler and turbine loads means that the flexibility of the unit's adjustments cannot be fully utilized in actual production.

[0004] 2. The peak-shaving function of gas holders needs further development. The capacity of gas holders is planned and designed based on the fluctuating gas volume during process production. Conventional steel enterprises primarily use gas holders for pressure stabilization, failing to fully explore their peak-shaving economic value. When there is a large surplus of gas during process production, due to the limited capacity of the gas holder, the excess gas is often disposed of by ignition in a venting tower, resulting in significant energy waste. Further development is needed for gas holders in short-term energy storage and long-term energy storage systems coupled with other production systems.

[0005] 3. Low- and medium-temperature waste heat power generation and saturated steam power generation have low energy efficiency. Waste heat resources in steel plants are mostly used for power generation via low- and medium-temperature or saturated steam methods, resulting in small-scale units and low energy efficiency. Saturated steam has a high moisture content, posing significant safety hazards. The steam parameters generated by flue gas heat recovery are somewhat unstable, causing frequent start-ups and shutdowns of waste heat power generation units and large load fluctuations, resulting in substantial economic losses.

[0006] 4. The peak-valley electricity price difference is widening. The rapid development of photovoltaic, wind, and hydropower in recent years has led to a gradual decline in the share of thermal power. Steel companies are also gradually increasing their allocation to wind power and rooftop photovoltaic systems. New energy power generation is highly volatile and seasonal, and the influx of new energy electricity has a significant impact on the power grid system. The large peak-valley electricity price difference is prompting and inducing energy-consuming enterprises to utilize off-peak energy storage to profit from the price difference. Summary of the Invention

[0007] In view of this, the purpose of the present invention is to provide a peak-shaving power generation system that couples a gas holder and molten salt energy storage, integrating the gas holder, gas boiler, molten salt system and peak-shaving gas boiler to match different operating conditions and achieve longer-term and more flexible energy storage regulation.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A peak-shaving power generation system coupling a gas holder and molten salt energy storage includes a gas storage system, a gas power generation system, a peak-shaving power generation system, and a molten salt system. The gas storage system includes at least one gas holder for supplying gas to the gas power generation system and the peak-shaving power generation system. The gas power generation system includes a gas boiler and a gas generator set, with the gas boiler generating steam to drive the gas generator set for power generation. The peak-shaving power generation system includes a peak-shaving gas boiler and a peak-shaving steam turbine generator set, with the peak-shaving gas boiler generating steam to drive the peak-shaving steam turbine generator set for power generation. The molten salt system uses molten salt and water as media for energy storage and release to match operating conditions. The gas power generation system and the molten salt system are coupled to the gas power generation system through the peak-shaving gas boiler.

[0010] Optionally, the gas storage system is connected to the peak-shaving gas boiler via the peak-shaving generator unit's gas regulating valve group; the gas storage system is also connected to the gas boiler via the gas generator unit's gas regulating valve group.

[0011] Optionally, the peak-shaving gas boiler includes at least two steam sources, one or more of which are saturated steam, connected to the peak-shaving gas boiler via a saturated steam regulating valve group; the other one or more of which are medium- and low-temperature superheated steam, connected to the peak-shaving gas boiler via a medium- and low-temperature superheated steam regulating valve group.

[0012] Optionally, the inlet parameters of the peak-shaving gas boiler shall meet the following conditions: the saturated steam pressure parameter is 0.5-1.6MPa and the temperature is the saturation temperature; the medium and low pressure superheated steam pressure parameter is ≤3.92MPa and the temperature is ≤450℃.

[0013] Optional, the main steam pressure parameter of the gas boiler and the main steam temperature parameter of the gas generator set are ≥13.7MPa and ≥540℃.

[0014] Optionally, the peak-shaving power generation system further includes a peak-shaving unit condenser, a peak-shaving unit condensate pump, and a regenerative heating system. The peak-shaving gas boiler, peak-shaving steam turbine generator set, peak-shaving unit condenser, peak-shaving unit condensate pump, and regenerative heating system are connected in sequence to form a loop.

[0015] Optionally, the gas power generation system further includes a power generation system steam switch, a gas power generation condenser, a gas power generation condensate pump, and a gas power generation regenerative system; the gas boiler, the power generation system steam switch, the gas generator set, the gas power generation condenser, the gas power generation condensate pump, and the gas power generation regenerative system are connected in sequence to form a loop.

[0016] Optionally, the gas-fired power generation regenerative system includes, in sequence, a shaft seal heater, a low-pressure heater, a deaerator, a feedwater pump, and a high-pressure heater.

[0017] Optionally, the molten salt system includes a molten salt energy storage and heat exchange system, a high-temperature molten salt storage tank, a high-temperature molten salt pump, a molten salt energy release and heat exchange system, a low-temperature molten salt storage tank, and a low-temperature molten salt pump, which are connected in sequence to form a loop.

[0018] Optionally, the molten salt energy storage heat exchange system is connected to the outlet of the gas boiler via a molten salt energy storage exhaust regulating valve group; the molten salt energy storage heat exchange system is reconnected to the inlet of the gas boiler via a molten salt energy storage return water pump.

[0019] Optionally, the gas power generation system is connected to the molten salt energy release heat exchange system via a molten salt energy release feedwater valve group and a molten salt energy release feedwater pump, and is then connected back to the outlet of the gas boiler.

[0020] Optionally, a molten salt electric heating unit is provided between the molten salt energy storage heat exchange system and the high-temperature molten salt storage tank, and a molten salt electric heating unit bypass valve is connected in parallel to the molten salt electric heating unit; a molten salt electric heating unit shut-off valve is provided on the molten salt electric heating unit.

[0021] Optionally, the molten salt energy release heat exchange system includes a preheater, an evaporative deaerator, and a first superheater connected in sequence; the molten salt energy storage heat exchange system includes a second superheater, a condensation deaerator, and a hot water heat exchanger connected in sequence.

[0022] Optionally, the gas boiler and the gas holder use surplus blast furnace gas, converter gas, coke oven gas, natural gas, or a mixture of two or more gas media.

[0023] Optionally, the system provides the following operating modes:

[0024] Energy storage working mode: Adjust the load of the gas power generation system to the minimum and use the molten salt system for energy storage. For long-term molten salt energy storage, the priority is higher than that of gas energy storage. The gas that cannot be stored is transported to the peak-shaving power generation system.

[0025] Energy release mode: Adjust the load of the gas power generation system to the maximum and use the molten salt system to release energy. For long periods of time, the priority of molten salt energy release is higher than that of gas energy release.

[0026] The beneficial effects of this invention are as follows:

[0027] This invention provides a peak-shaving power generation system that couples a gas holder and molten salt energy storage. This system allows the gas boiler to maintain a relatively efficient combustion load for peak power generation without reducing its operating load, utilizing main steam extraction or feedwater to regulate the power generation load. By linking it to the gas holder, it achieves short-term gas storage combined with long-term molten salt thermal storage, resulting in more flexible system energy storage and greater economic benefits from peak-valley electricity pricing compared to short-term energy storage. Transporting gas to the peak-shaving gas boiler effectively improves the steam parameters for waste heat power generation, reduces steam moisture content, and thus improves the operating efficiency and safety of the waste heat power generation unit, generating more self-generated electricity.

[0028] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0029] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0030] Figure 1 This is a system diagram of the present invention.

[0031] Figure label:

[0032] 1. Peak-shaving gas boiler; 2. Peak-shaving steam turbine generator set; 3. Peak-shaving unit condenser; 4. Peak-shaving unit condensate pump; 5. Regenerative heating system; 6. Gas holder group; 7. Saturated steam regulating valve group; 8. Medium and low temperature superheated steam regulating valve group; 9. Peak-shaving unit gas regulating valve group; 10. Molten salt energy storage steam extraction regulating valve group; 11. Gas regulating valve group; 12. Gas boiler; 13. Gas generator set; 14. Gas generator condenser; 15. Gas generator condensate pump. 16. Gas-fired power generation regenerative system; 17. Molten salt energy storage return water pump; 18. Molten salt energy release feed water valve group; 19. Molten salt energy release feed water pump; 20. Molten salt energy release heat exchange system; 21. Low temperature molten salt storage tank; 22. Low temperature molten salt pump; 23. Molten salt energy storage heat exchange system; 24. Molten salt electric heater; 25. Molten salt electric heater bypass valve; 26. Molten salt electric heater shut-off valve; 27. High temperature molten salt storage tank; 28. High temperature molten salt pump; 29. ​​Gas-fired power generation main steam regulating valve. Detailed Implementation

[0033] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0034] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0035] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0036] Please see Figure 1 This invention designs a peak-shaving power generation system coupling a gas holder and molten salt energy storage, including a peak-shaving gas boiler 1, a peak-shaving steam turbine generator set 2, a peak-shaving unit condenser 3, a peak-shaving unit condensate pump 4, a regenerative heating system 5, a gas holder group 6, a saturated steam regulating valve group 7, a medium- and low-temperature superheated steam regulating valve group 8, a peak-shaving unit gas regulating valve group 9, a molten salt energy storage extraction steam regulating valve group 10, a gas power generation gas regulating valve group 11, a gas boiler 12, a gas generator set 13, and a gas power generation system. 14. Condenser, 15. Condensate pump for gas power generation, 16. Regenerative system for gas power generation, 17. Molten salt energy storage return water pump, 18. Molten salt energy release feedwater valve group, 19. Molten salt energy release feedwater pump, 20. Molten salt energy release heat exchange system, 21. Low temperature molten salt storage tank, 22. Low temperature molten salt pump, 23. Molten salt energy storage heat exchange system, 24. Molten salt electric heater, 25. Molten salt electric heater bypass valve, 26. Molten salt electric heater shut-off valve, 27. High temperature molten salt storage tank, 28. High temperature molten salt pump, 29. Main steam regulating valve for gas power generation.

[0037] The system comprises four subsystems:

[0038] ① Gas storage system: Gas holder group 6 is connected to peak-shaving gas boiler 1, and the connecting pipeline is equipped with peak-shaving unit gas regulating valve group 9 to regulate the gas volume. Gas holder group 6 is connected to gas boiler 12, and the connecting pipeline is equipped with gas generator set 13 gas regulating valve group to regulate the gas volume.

[0039] ② Molten Salt System: The cryogenic molten salt storage tank 21 is connected to the cryogenic molten salt pump 22, which pumps the molten salt to the molten salt energy storage heat exchange system 23 for heating. The heated molten salt is then connected to the molten salt electric heater 24. Under normal circumstances, the molten salt electric heater shut-off valve 26 is closed, and the molten salt electric heater bypass valve 25 is open. When additional heating is required, the molten salt electric heater shut-off valve 26 is opened, and the molten salt electric heater bypass valve 25 is closed. After heating, the molten salt is piped to the high-temperature molten salt storage tank 27 for storage. The high-temperature molten salt storage tank 27 is connected to the high-temperature molten salt pump 28, which pumps the molten salt to the molten salt energy release heat exchange system 20 for cooling. This system is connected to the cryogenic molten salt storage tank 21, completing the entire molten salt system connection.

[0040] ③ Gas-fired power generation system: Gas boiler 12 generates main steam, which is sent to gas generator set 13 through pipeline. After the steam does work in the turbine, it is sent to the condenser for condensation through pipeline. The condenser is connected to the gas-fired power generation condensate pump 15 and the gas-fired power generation regenerative system 16 through pipeline. The regenerative system includes shaft seal, low-pressure heater, deaerator, feedwater pump and high-pressure heater equipment in sequence. After the condensate is heated and deaerated, it is finally sent to the feedwater inlet of gas boiler 12 through pipeline.

[0041] After deoxygenation, the gas-fired power generation regenerative system 16 leads out a feedwater line, which is connected to the molten salt energy release system through a pipeline. The pipeline is first connected to the molten salt energy release feedwater valve group 18, then to the molten salt energy release feedwater pump 19, and finally to the molten salt energy release heat exchange system 20. The feedwater is heated into superheated steam and then flows into the main steam pipeline at the outlet of the gas boiler 12, which in turn drives the gas generator set 13 to generate electricity.

[0042] Steam is drawn from the main steam pipeline at the outlet of the gas boiler 12. After passing through the molten salt energy storage extraction steam regulating valve group 10, it is connected to the molten salt energy storage heat exchange system 23. The steam after heat exchange is condensed into feedwater. The cooled feedwater is connected to the molten salt energy storage return water pump 17. After being pressurized, it flows into the feedwater inlet of the gas boiler 12.

[0043] ④ Peak-shaving power generation system: Peak-shaving gas boiler 1 includes at least two steam sources for supplementary steam. One or more of these sources are saturated steam, which is sent to peak-shaving gas boiler 1 via pipeline after passing through the saturated steam regulating valve group 7 from the external network. The other one or more sources are medium- and low-temperature superheated steam, which is sent to peak-shaving gas boiler 1 via pipeline after passing through the medium- and low-temperature superheated steam regulating valve group 8. The outlet steam of peak-shaving gas boiler 1 is connected to peak-shaving turbine generator set 2 via pipeline. After steam power generation, the turbine is connected to the condenser 3 of the peak-shaving unit via pipeline. The cooled condensate is first connected to the condensate pump 4 of the peak-shaving unit via pipeline, and then connected to the regenerative heating system 5 via pipeline. Finally, the regeneratively heated feedwater is sent to peak-shaving gas boiler 1 via pipeline.

[0044] The gas holder group 6 is connected to both peak-shaving gas boiler 1 and gas boiler 12 via the plant's gas pipeline network. Peak-shaving gas boiler 1 and gas boiler 12 are respectively connected to peak-shaving steam turbine generator set 2 and gas generator set 13 via steam pipelines. The gas pipelines connecting the outlet of gas holder group 6 to gas boiler 12 and peak-shaving gas boiler 1 are respectively equipped with gas generator gas regulating valve group 11 and peak-shaving unit gas regulating valve group 9, which can freely adjust the amount of gas on both sides.

[0045] The peak-shaving gas boiler 1 includes at least two steam sources. One source of multiple saturated steam is connected to the peak-shaving gas boiler 1 via a saturated steam regulating valve group 7, and the other source of one or more medium- and low-temperature superheated steam is connected to the peak-shaving gas boiler 1 via a medium- and low-temperature superheated steam regulating valve group 8. The steam inlet parameters of the peak-shaving gas boiler 1 meet the following conditions: the saturated steam pressure is 0.5-1.6 MPa, and the temperature is the saturation temperature; the medium- and low-pressure superheated steam pressure is ≤3.92 MPa, and the temperature is ≤450℃.

[0046] The gas generator set 13 can be an ultra-high temperature and ultra-high pressure turbine, a subcritical ultra-high temperature turbine, or a supercritical ultra-high temperature turbine, with a pressure parameter ≥13.7MPa and a temperature parameter ≥540℃, employing reheat technology. The gas boiler 12 can be an ultra-high temperature and ultra-high pressure gas boiler, a subcritical ultra-high temperature gas boiler, or a supercritical ultra-high temperature gas boiler, with a pressure parameter ≥13.7MPa and a temperature parameter ≥540℃, employing reheat technology. The gas generator set 13 and the peak-shaving turbine generator set 2 are connected to the plant's power grid via transformers. Peak-shaving gas boiler 1, gas boiler 12, peak-shaving turbine generator set 2, and gas generator set 13 are all wide-load peak-shaving units. By coupling the molten salt energy storage and release with the power generation system, the operation of molten salt energy storage or molten salt energy release can be selected according to the actual power generation needs. The molten salt energy storage extraction steam regulating valve group 10 or the molten salt energy release feedwater valve group 18 can be selected for opening and closing.

[0047] The peak-shaving unit gas regulating valve group 9, the gas power generation gas regulating valve group 11, the molten salt energy storage steam extraction regulating valve group 10, and the molten salt energy release feedwater valve group 18 are intelligently connected, allowing for the regulation of gas supply, steam extraction, and feedwater delivery according to actual power generation needs. The molten salt electric heater 24 can be flexibly activated by adjusting the molten salt electric heater bypass valve 25 and the molten salt electric heater shut-off valve 26. The molten salt used in the molten salt system is a multi-element mixed inorganic salt with an operating temperature range of 150℃ to 800℃.

[0048] Steam extracted from the main steam source is cooled from superheated steam via molten salt energy storage heat exchange system 23. After passing through molten salt energy storage return water pump 17, it is cooled and depressurized to the feedwater parameters of the gas boiler 12. Deoxygenated water from molten salt energy release feedwater pump 19 is heated and pressurized to the superheated steam parameters of the generator main steam source after passing through molten salt energy release heat exchange system 20. The gas boiler 12 and the gas holder group 6 may use surplus blast furnace gas, converter gas, coke oven gas, natural gas, or a mixture of two or more gas media.

[0049] Peak-shaving gas boiler 1 can regulate the unit's power generation load by adjusting the peak-shaving unit's gas regulating valve group 9. For supplementary steam, the saturated steam temperature can be increased to above the superheat parameters (superheat ≥ 70℃), and after appropriate pressure enhancement, it can be sent separately to the peak-shaving turbine interstage. The medium- and low-temperature superheated steam temperature parameters can be increased to above the high-temperature parameters (temperature ≥ 540℃), and after appropriate pressure enhancement, it can be sent separately to the peak-shaving turbine interstage. The peak-shaving gas boiler 1 generates superheated steam through gas combustion, and the main superheated steam parameters can reach high temperature and high pressure (steam pressure ≥ 9.8 MPa, temperature ≥ 510℃).

[0050] This system is characterized by comprising a gas storage system, a molten salt system, a gas power generation system, and a peak-shaving power generation system. The peak-shaving power generation system utilizing the above-mentioned coupled gas holder and molten salt energy storage specifically includes the following operational steps:

[0051] (1) Energy storage working mode

[0052] During off-peak electricity demand periods, the main steam regulating valve 29 of the gas-fired power generation unit is adjusted to minimize the load of the gas-fired generator unit 13. While ensuring the overall gas balance and pressure stability of the plant, the gas-fired power generation gas regulating valve group 11 and the molten salt energy storage extraction steam regulating valve group 10 are adjusted to maximize the energy storage capacity of the gas holder and molten salt. Molten salt energy storage has higher priority than gas holder energy storage for long-term energy storage. Gas that cannot be stored in the gas holder is regulated by the peak-shaving unit gas regulating valve group 9 and sent to the peak-shaving gas boiler 1.

[0053] Specifically, for long-term energy storage, molten salt system thermal storage is prioritized, followed by gas holder group 6 energy storage. Due to a significant reduction in load on gas generator unit 13, a substantial amount of gas remains. This surplus gas is sent to peak-shaving gas boiler 1 via peak-shaving unit gas regulating valve group 9 to supplement the combustion heating of saturated steam and medium-low temperature superheated steam recovered throughout the plant. While ensuring the economical operating load of peak-shaving turbine generator unit 2, the surplus gas is then sent to gas holder group 6 for storage.

[0054] Under energy storage conditions, the molten salt energy storage extraction steam regulating valve group 10 is open, and the molten salt energy release feedwater valve group 18 is closed. The system regulates the opening of the gas-fired power generation gas regulating valve group 11, the molten salt energy storage extraction steam regulating valve group 10, and the gas-fired power generation main steam regulating valve 29. This regulates the extraction of steam from the gas boiler 12 to the molten salt energy storage system. After heat exchange in the molten salt energy storage heat exchange system 23, the steam is cooled and then passes through the molten salt energy storage return water pump 17, which then collects the feedwater into the feedwater inlet pipe of the gas boiler 12. This regulation can minimize the power generation load of the gas generator set 13 and achieve maximum long-term molten salt energy storage and short-term gas holder energy storage.

[0055] The cryogenic molten salt pump 22 is started to send the cold molten salt in the cryogenic molten salt storage tank 21 to the molten salt energy storage heat exchange system 23 for heat exchange. After being heated, it is then transported to the high-temperature molten salt storage tank 27 for storage. If the molten salt storage temperature meets the storage requirements after heat exchange in the molten salt energy storage heat exchange system 23, the molten salt electric heater bypass valve 25 is opened and the molten salt electric heater shut-off valve 26 is closed. If the molten salt storage temperature does not meet the storage requirements after heat exchange in the molten salt energy storage heat exchange system 23, the molten salt electric heater shut-off valve 26 is opened and the molten salt electric heater bypass valve 25 is closed.

[0056] (2) Energy release working mode

[0057] Under this operating condition, long-term energy release will prioritize the release of heat stored in the molten salt system, followed by the release of energy stored in the gas holder group 6. The remaining gas will prioritize powering the gas boiler 12, then the peak-shaving gas boiler 1, then the gas generator unit 13 at full load, then the peak-shaving steam turbine generator unit 2 at full load, and finally, the remaining gas can be reserved for use in non-energy storage release conditions.

[0058] Specifically, during peak electricity consumption periods, the main steam regulating valve 29 of the gas-fired power generation unit is adjusted to maximize the load of the gas generator set 13. While ensuring the overall gas pressure balance of the plant, the gas regulating valve group 11 and the molten salt energy release feedwater valve group 18 are adjusted to maximize the energy release from the gas holder and the molten salt. For long-term energy release, the molten salt release takes precedence over the gas holder release.

[0059] In the energy release operation, the molten salt energy storage extraction steam regulating valve group 10 is closed, and the molten salt energy release feedwater valve group 18 is opened. The system regulates the opening of the gas-fired power generation gas regulating valve group 11, the molten salt energy release feedwater valve group 18, and the gas-fired power generation main steam regulating valve 29 to fully release the heat stored in the molten salt system. After passing through the molten salt energy release feedwater valve group 18, the feedwater is transported to the molten salt energy release heat exchange system 20 via the molten salt energy release feedwater pump 19. After being heated, the superheated steam flows into the main steam pipeline at the outlet of the gas boiler 12. The regulation can adjust the power generation load of the gas generator set 13 to the maximum and achieve maximum long-term energy release of molten salt and short-term energy release of the gas holder.

[0060] Start the high-temperature molten salt pump 28 to send the high-temperature molten salt to the molten salt energy release heat exchange system 20 for heat exchange, and send the cooled molten salt to the low-temperature molten salt storage tank 21 for storage.

[0061] 3. In non-energy storage and release conditions, the molten salt system can selectively put into operation either the molten salt energy storage system or the molten salt energy release system based on the heat balance results of the above two conditions.

[0062] Based on the gas balance results of the above two operating conditions, the gas storage system selectively adjusts the gas regulating valve group 9 of the gas regulating and peak shaving unit and the gas regulating valve group 11 of the gas power generation unit to ensure that the peak shaving turbine generator unit 2 is above the economic operating load, maximize the power generation of the peak shaving turbine generator unit 2, and ensure that the gas storage of the gas holder group 6 is at the minimum load before the energy storage operating period.

[0063] This system can effectively participate in the plant's grid peak shaving, effectively integrating high-efficiency coal gas power generation with the plant's saturated steam power generation and medium- and low-temperature waste heat steam power generation. It optimizes the plant's gas, steam, and electricity balance by utilizing short-term coal gas storage in gas holders and long-term molten salt thermal storage. Actual production can be adjusted in a timely manner according to regional peak-valley electricity price characteristics and coal gas production and sales characteristics, increasing the plant's self-generated electricity and grid-connected electricity during peak hours, and reducing self-generated electricity and increasing purchased electricity during off-peak hours. This reduces power generation and consumption costs.

[0064] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A peak-shaving power generation system coupling a gas holder and molten salt energy storage, characterized in that: This includes gas storage systems, gas power generation systems, peak-shaving power generation systems, and molten salt systems; The gas storage system includes at least one gas holder for supplying gas to the gas power generation system and the peak-shaving power generation system. The gas power generation system includes a gas boiler (12), a gas generator set (13), and a gas power generation reheat system (16) connected in sequence to form a loop. The gas boiler (12) generates steam to drive the gas generator set (13) to generate electricity. The peak-shaving power generation system includes a peak-shaving gas boiler (1) and a peak-shaving steam turbine generator set (2). The peak-shaving gas boiler (1) generates steam to drive the peak-shaving steam turbine generator set (2) to generate electricity. The molten salt system uses molten salt and water as media for energy storage and release to match operating conditions; The molten salt system is coupled to the gas power generation system via the gas boiler (12); The gas storage system is connected to the peak-shaving gas boiler (1) via the peak-shaving unit gas regulating valve group (9); the gas storage system is connected to the gas boiler (12) via the gas regulating valve group (11); The molten salt system includes a molten salt energy storage and heat exchange system (23), a high-temperature molten salt storage tank (27), a molten salt energy release and heat exchange system (20), and a low-temperature molten salt storage tank (21), which are connected in sequence to form a loop. The molten salt energy storage heat exchange system (23) is connected to the outlet of the gas boiler (12) via the molten salt energy storage exhaust regulating valve group (10); the molten salt energy storage heat exchange system (23) is connected back to the inlet of the gas boiler (12) via the molten salt energy storage return water pump (17); The gas power generation regenerative system (16) is connected to the molten salt energy release heat exchange system (20) via the molten salt energy release water valve group (18), and is connected back to the outlet of the gas boiler (12).

2. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The peak-shaving gas boiler (1) contains at least two steam sources, one or more of which are saturated steam, which are connected to the peak-shaving gas boiler (1) through a saturated steam regulating valve group (7); the other one or more are medium-low temperature superheated steam, which are connected to the peak-shaving gas boiler (1) through a medium-low temperature superheated steam regulating valve group (8).

3. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 2, characterized in that: The inlet parameters of the peak-shaving gas boiler (1) meet the following conditions: the saturated steam pressure parameter is 0.5-1.6MPa and the temperature is the saturation temperature; the medium and low pressure superheated steam pressure parameter is ≤3.92MPa and the temperature is ≤450℃.

4. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: Gas boiler (12), gas generator set (13) main steam pressure parameter of turbine ≥13.7MPa, main steam temperature parameter ≥540℃.

5. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The peak-shaving power generation system also includes a peak-shaving unit condenser (3), a peak-shaving unit condensate pump (4), and a regenerative heating system (5). The peak-shaving gas boiler (1), the peak-shaving steam turbine generator set (2), the peak-shaving unit condenser (3), the peak-shaving unit condensate pump (4), and the regenerative heating system (5) are connected in sequence to form a loop.

6. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The gas power generation system also includes a power generation system steam switch, a gas power generation condenser (14), and a gas power generation condensate pump (15); the power generation system steam switch, gas generator set (13), gas power generation condenser (14), and gas power generation condensate pump (15) are connected in sequence between the gas boiler (12) and the gas power generation regenerative system (16).

7. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The gas power generation regenerative system (16) includes, in sequence, a shaft seal heater, a low-pressure heater, a deaerator, a feed water pump, and a high-pressure heater.

8. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The molten salt system also includes a high-temperature molten salt pump (28) and a low-temperature molten salt pump (22). The high-temperature molten salt pump (28) is located between the high-temperature molten salt storage tank (27) and the molten salt energy release heat exchange system (20), and the low-temperature molten salt pump (22) is located between the low-temperature molten salt storage tank (21) and the molten salt energy storage heat exchange system (23).

9. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: A molten salt energy release water supply pump (19) is provided between the molten salt energy release water supply valve group (18) and the molten salt energy release heat exchange system (20).

10. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: A molten salt electric heater (24) is provided between the molten salt energy storage heat exchange system (23) and the high-temperature molten salt storage tank (27). A molten salt electric heating unit bypass valve (25) is connected in parallel with the molten salt electric heating unit. A molten salt electric heater shut-off valve (26) is provided on the molten salt electric heater (24).

11. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The molten salt energy release heat exchange system (20) includes a preheater, an evaporative deaerator, and a first superheater connected in sequence; the molten salt energy storage heat exchange system (23) includes a second superheater, a condenser deaerator, and a hot water heat exchanger connected in sequence.

12. The peak-shaving power generation system with coupled gas holder and molten salt energy storage according to claim 1, characterized in that: The gas boiler (12) and the gas holder use surplus blast furnace gas, converter gas, coke oven gas, natural gas, or a mixture of two or more gas media.

13. The peak-shaving power generation system with coupled gas holder and molten salt energy storage as described in any one of claims 1-12, characterized in that: The following working modes are available: Energy storage working mode: Adjust the load of the gas generator set (13) to the minimum and use the molten salt system for energy storage. The priority of long-term energy storage molten salt energy storage is higher than that of gas holder (6) energy storage. The gas that cannot be stored is transported to the peak shaving power generation system. Energy release working mode: Adjust the load of the gas generator set (13) to the maximum and use the molten salt system to release energy. The molten salt release priority is higher than the gas holder (6) release energy during long-term energy release.

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