Thermal power plant peak regulation system based on electric power spot transaction

Abstract

The invention relates to the technical field of thermal power plant peak regulation, in particular to a thermal power plant peak regulation system based on electric power spot transaction. The peak shaving system comprises a boiler system used for generating high-pressure main steam and reheat steam in the production process and a steam turbine power generation system used for generating power according to the high-pressure main steam generated by the boiler system, and further comprises a control system and a power supply system, the control module is used for generating a first control instruction according to the obtained real-time electricity price and preset electricity price of the electric power spot market, and sending the first control instruction to the fused salt heat storage and exchange system; the fused salt heat storage and exchange system is used for extracting high-pressure main steam and reheated steam generated by the boiler system according to the first control instruction to perform heat exchange with pre-stored low-temperature fused salt; and the extracted high-pressure main steam generated by the boiler system is converted into a liquid-state water solution, the reheated steam is converted into low-temperature steam, and the low-temperature fused salt is converted into high-temperature fused salt.

Description

Technical Field

[0001] The present invention relates to the technical field of peak load regulation in thermal power plants, and in particular to a peak load regulation system for thermal power plants based on spot electricity trading. Background Art

[0002] The traditional electricity trading model is dominated by the power grid, and the supply and demand of electricity are carried out through long-term contracts. There are problems such as imbalance between supply and demand, information asymmetry, and inefficient resource allocation. With the reform of the power market, electricity spot trading has gradually become a hot topic in the industry.

[0003] Electricity spot trading refers to the electricity trading method in the electricity market, which is to conduct instant transactions at a fixed price at the current electricity trading time. After the establishment of the electricity spot market, the electricity supply and demand parties can directly trade through the market mechanism, and the electricity price is determined by the market supply and demand relationship. This real-time supply and demand matching mechanism realizes the optimal scheduling of power resources, solves the imbalance between supply and demand, greatly reduces resource waste, and improves the efficiency of power resource utilization.

[0004] Currently, the more mature peak-shaving transformation technologies for coal-fired power units in thermal power plants mainly include peak-shaving transformation of the unit itself, low-load coordinated control, and the use of thermal-electric decoupling technology for cogeneration units. However, they generally have problems such as insufficient peak-shaving capacity of the units, low response speed, and high coal consumption. Summary of the invention

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a peak-shaving system for a thermal power plant based on spot electricity trading.

[0006] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0007] The embodiment of the present invention provides a peak-shaving system for a thermal power plant based on spot electricity trading, wherein the peak-shaving system includes a boiler system for generating high-pressure main steam and reheated steam in a production process and a steam turbine power generation system for generating electricity according to the high-pressure main steam generated by the boiler system, and the peak-shaving system also includes:

[0008] A control system, configured to generate a first control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, and send the first control instruction to the molten salt heat storage and exchange system;

[0009] The molten salt heat storage and exchange system is used to extract the high-pressure main steam and reheated steam generated by the boiler system according to the first control instruction, and exchange heat with the pre-stored low-temperature molten salt respectively, so that the extracted high-pressure main steam generated by the boiler system is converted into a liquid aqueous solution, the reheated steam is converted into low-temperature steam, and the low-temperature molten salt is converted into a high-temperature molten salt.

[0010] Preferably, the molten salt heat storage and exchange system comprises: a molten salt / main steam heat exchanger 13, a molten salt / reheat steam heat exchanger 12, and a first valve device 10, a second valve device 11, a high-temperature molten salt storage tank 15 and a low-temperature molten salt storage tank 14 respectively connected to the control system;

[0011] The first valve device 10 is arranged on the first pipeline and connected to the air inlet of the molten salt / main steam heat exchanger 13, and is used to extract the high-pressure main steam in the first pipeline and transport it to the molten salt / main steam heat exchanger 13 according to the first control instruction;

[0012] The first pipeline is a pipeline for high-pressure main steam generated by the boiler superheater 1 in the boiler system to enter the high-pressure cylinder 3 in the steam turbine power generation system;

[0013] The second valve device 11 is arranged on the second pipeline and connected to the air inlet of the molten salt / reheat steam heat exchanger 12, and is used to extract the reheat steam in the second pipeline and transport it to the molten salt / reheat steam heat exchanger 12 according to the first control instruction;

[0014] The second pipeline is a pipeline for the reheated steam generated by the boiler reheater 2 in the boiler system to enter the intermediate pressure cylinder 4 in the steam turbine power generation system;

[0015] The salt outlet of the low-temperature molten salt storage tank 14 is connected to the salt inlet of the molten salt / main steam heat exchanger 13 and the salt inlet of the molten salt / reheat steam heat exchanger 12, respectively, for transmitting the stored low-temperature molten salt to the molten salt / main steam heat exchanger 13 and the molten salt / reheat steam heat exchanger 12 according to the first control instruction;

[0016] The molten salt / main steam heat exchanger 13 is used to use low-temperature molten salt to perform heat exchange on the input high-pressure main steam, so that the high-pressure main steam is converted into a liquid aqueous solution and the low-temperature molten salt is converted into a high-temperature molten salt;

[0017] The molten salt / reheat steam heat exchanger 12 is used to perform heat exchange on the input reheat steam using low-temperature molten salt, so that the reheat steam is converted into low-temperature steam and the low-temperature molten salt is converted into high-temperature molten salt.

[0018] Preferably,

[0019] The molten salt heat storage and exchange system is also used to return the converted liquid aqueous solution and low-temperature steam to the boiler system, and to store the converted high-temperature molten salt in the high-temperature molten salt storage tank 15.

[0020] Preferably,

[0021] The salt outlet of the molten salt / main steam heat exchanger 13 and the salt outlet of the molten salt / reheat steam heat exchanger 12 are both connected to the salt inlet of the high-temperature molten salt storage tank 15;

[0022] The water outlet of the liquid aqueous solution converted by the molten salt / main steam heat exchanger 13 is connected to the water supply port of the boiler superheater 1 in the boiler system;

[0023] The outlet of the low-temperature steam converted by the molten salt / reheat steam heat exchanger 12 is connected to the air inlet of the boiler reheater 2 .

[0024] Preferably,

[0025] The control system is further used to generate a second control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, and send the second control instruction to the molten salt heat storage and exchange system;

[0026] The molten salt heat storage and exchange system is used to use the pre-stored high-temperature molten salt to exchange heat with the condensed water generated by the steam turbine power generation system according to the second control instruction, so that the condensed water is converted into water vapor and the high-temperature molten salt is converted into low-temperature molten salt.

[0027] Preferably,

[0028] The molten salt heat storage and exchange system is also used to input the water vapor converted from the condensed water generated by the steam turbine power generation system into the steam turbine power generation system, and to store the converted low-temperature molten salt in the low-temperature molten salt storage tank 14 .

[0029] Preferably,

[0030] The molten salt heat storage and exchange system further comprises: a molten salt / water heat exchanger 16;

[0031] The salt inlet of the molten salt / water heat exchanger 16 is connected to the salt outlet of the high-temperature molten salt storage tank 15;

[0032] The high-temperature molten salt storage tank 15 is also used to transfer the stored high-temperature molten salt to the molten salt / water heat exchanger 16 according to the second control instruction;

[0033] The salt outlet of the molten salt / water heat exchanger 16 is connected to the salt inlet of the low-temperature molten salt storage tank 14;

[0034] The molten salt / water heat exchanger 16 is used to use high-temperature molten salt to perform heat exchange on condensed water generated by the steam turbine power generation system, so that the condensed water is converted into water vapor and the high-temperature molten salt is converted into low-temperature molten salt.

[0035] Preferably,

[0036] The water inlet of the molten salt / water heat exchanger 16 is connected to the water outlet of the deaerator 8 for discharging condensed water in the steam turbine power generation system through a water pump.

[0037] Preferably,

[0038] The high-temperature steam outlet of the molten salt / water heat exchanger 16 is connected to the low-pressure cylinder 5 in the steam turbine power generation system.

[0039] Preferably,

[0040] The control system generates a first control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, which specifically includes:

[0041] When the real-time electricity price in the electricity spot market is lower than a preset value of the preset electricity price, a first control instruction is generated;

[0042] The control system generates a second control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, specifically including:

[0043] When the real-time electricity price in the electricity spot market is higher than a preset value of the preset electricity price, a second control instruction is generated.

[0044] The beneficial effects of the present invention are as follows: a peak-shaving system for a thermal power plant based on spot electricity trading of the present invention, because the control system extracts the high-pressure main steam and reheated steam generated by the boiler system through the molten salt energy storage system and exchanges heat with the pre-stored low-temperature molten salt respectively, so that the extracted high-pressure main steam generated by the boiler system is converted into a liquid aqueous solution, the reheated steam is converted into low-temperature steam, and the low-temperature molten salt is converted into a high-temperature molten salt, thereby being able to store excess heat when the electricity price in the electricity spot market is low, and releasing the stored heat for power generation when the electricity price is high, effectively buffering the rigid connection between the boiler and the steam turbine, so that the thermal power plant can flexibly adjust the output power according to the demand of the electricity market, and improving the regulation ability of the thermal power plant in the electricity market with large load fluctuations.

[0045] The invention discloses a thermal power plant peak load regulation system based on spot electricity trading. When the real-time electricity price is low, the control system extracts the high-pressure main steam and reheat steam generated by the boiler system through the molten salt energy storage system and exchanges heat with the pre-stored low-temperature molten salt, respectively, so that the boiler system can maintain stable low-load operation without being completely shut down. When the boiler system stores energy during the low-price period, it can also reduce the minimum load of the thermal power unit, avoid frequent startup and shutdown of the boiler system, reduce heat loss and equipment wear, and ensure the safe and stable operation of the boiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a schematic diagram of a peak load regulation system for a thermal power plant based on spot electricity trading in an embodiment of the present invention.

[0047] Description of Reference Numerals

[0048] 1: Boiler superheater;

[0049] 2: Boiler reheater;

[0050] 3: High pressure cylinder;

[0051] 4: Medium pressure cylinder;

[0052] 5: Low pressure cylinder;

[0053] 6: Condenser;

[0054] 7: Low pressure heater;

[0055] 8: Deaerator;

[0056] 9: High voltage heater;

[0057] 10: first valve device;

[0058] 11: second valve device;

[0059] 12: Molten salt / reheat steam heat exchanger;

[0060] 13: Molten salt / main steam heat exchanger;

[0061] 14: Low temperature molten salt storage tank;

[0062] 15: High temperature molten salt storage tank;

[0063] 16: Molten salt / water heat exchanger;

[0064] 17: Generator. DETAILED DESCRIPTION

[0065] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation modes in conjunction with the accompanying drawings.

[0066] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0067] Embodiment 1

[0068] See also Figure 1 This embodiment provides a peak-shaving system for a thermal power plant based on spot electricity trading, the peak-shaving system comprising a boiler system for generating high-pressure main steam and reheated steam in a production process and a steam turbine power generation system for generating electricity according to the high-pressure main steam generated by the boiler system, the peak-shaving system further comprising:

[0069] A control system, configured to generate a first control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, and send the first control instruction to the molten salt heat storage and exchange system;

[0070] The molten salt heat storage and exchange system is used to extract the high-pressure main steam and reheated steam generated by the boiler system according to the first control instruction, and exchange heat with the pre-stored low-temperature molten salt respectively, so that the extracted high-pressure main steam generated by the boiler system is converted into a liquid aqueous solution, the reheated steam is converted into low-temperature steam, and the low-temperature molten salt is converted into a high-temperature molten salt.

[0071] In this embodiment, by real-time monitoring of electricity price fluctuations in the electricity spot market, the peak load regulation system of the thermal power plant can dynamically adjust the power generation load. When the electricity price is low, the power generation load can be reduced, and part of the heat of the high-pressure main steam and reheated steam can be transferred to the molten salt heat storage and exchange system. This method avoids ineffective high-cost power generation and helps reduce production costs.

[0072] In the practical application of this embodiment, the molten salt heat storage and exchange system includes: a molten salt / main steam heat exchanger 13, a molten salt / reheat steam heat exchanger 12, and a first valve device 10, a second valve device 11, a high-temperature molten salt storage tank 15 and a low-temperature molten salt storage tank 14 respectively connected to the control system;

[0073] The first valve device 10 is arranged on the first pipeline and connected to the air inlet of the molten salt / main steam heat exchanger 13, and is used to extract the high-pressure main steam in the first pipeline and transport it to the molten salt / main steam heat exchanger 13 according to the first control instruction;

[0074] In this embodiment, the setting of the first valve device 10 enables the system to control the opening and closing of the first valve device 10 through the first control instruction, and can introduce part of the high-pressure steam in the first pipeline into the heat exchanger to exchange heat with the molten salt to achieve heat energy transfer.

[0075] The first pipeline is a pipeline for high-pressure main steam generated by the boiler superheater 1 in the boiler system to enter the high-pressure cylinder 3 in the steam turbine power generation system;

[0076] In this embodiment, the high-pressure main steam generated by the boiler superheater 1 enters the high-pressure cylinder 3, the medium-pressure cylinder 4 and the low-pressure cylinder 5 in the steam turbine power generation system through the first pipeline. The high-pressure main steam is continuously acted upon by the high-pressure cylinder 3, the medium-pressure cylinder 4 and the low-pressure cylinder 5, and the thermal energy of the high-pressure main steam is converted into mechanical energy to drive the generator 17 to generate electricity.

[0077] In this embodiment, the steam turbine power generation system further includes a condenser 6 and a heating device, wherein the condenser 6 and the heating device are arranged on the connecting pipe between the low-pressure cylinder of the steam turbine and the boiler, and the heating device includes a low-pressure heater 7 and a high-pressure heater 9. The condenser is used to condense the steam discharged from the low-pressure cylinder 5 into condensed water, and the condensed water is heated by the low-pressure heater 7 and then added to the deaerator 8 to remove the gas in the condensed water, and then heated by the high-pressure heater 9 and transported to the boiler as the main feed water of the boiler, so as to realize the effective circulation of steam in the thermal power unit.

[0078] The second valve device 11 is arranged on the second pipeline and connected to the air inlet of the molten salt / reheat steam heat exchanger 12, and is used to extract the reheat steam in the second pipeline and transport it to the molten salt / reheat steam heat exchanger 12 according to the first control instruction;

[0079] In this embodiment, the setting of the second valve device 11 enables the system to control the opening and closing of the second valve device 11 through the first control instruction, so that the reheated steam flows to the molten salt heat exchanger, which can realize the transfer and storage of steam thermal energy and provide a stable heat source for subsequent power generation.

[0080] The second pipeline is a pipeline for the reheated steam generated by the boiler reheater 2 in the boiler system to enter the intermediate pressure cylinder 4 in the steam turbine power generation system;

[0081] The salt outlet of the low-temperature molten salt storage tank 14 is connected to the salt inlet of the molten salt / main steam heat exchanger 13 and the salt inlet of the molten salt / reheat steam heat exchanger 12, respectively, for transmitting the stored low-temperature molten salt to the molten salt / main steam heat exchanger 13 and the molten salt / reheat steam heat exchanger 12 according to the first control instruction;

[0082] In this embodiment, the salt outlet of the low-temperature molten salt storage tank 14 is respectively connected to the salt inlet of the molten salt / main steam heat exchanger 13 and the salt inlet of the molten salt / reheat steam heat exchanger 12, providing a flexible molten salt transmission path, which can cool and store high-pressure main steam and reheat steam respectively. The low-temperature molten salt is transmitted from the storage tank to different heat exchangers so that the steam is sufficiently cooled when entering the heat exchanger, helping the steam to release heat energy to the molten salt, thereby achieving efficient heat exchange.

[0083] The molten salt / main steam heat exchanger 13 is used to use low-temperature molten salt to perform heat exchange on the input high-pressure main steam, so that the high-pressure main steam is converted into a liquid aqueous solution and the low-temperature molten salt is converted into a high-temperature molten salt;

[0084] In this embodiment, the molten salt / main steam heat exchanger 13 can effectively store the heat energy of the high-pressure main steam in the molten salt and cool the steam to a liquid water state to reduce the energy waste of the steam. Through heat exchange, the energy in the high-pressure main steam is transferred to the molten salt, and the steam is cooled to water, thereby avoiding the energy loss of direct steam release and improving energy utilization efficiency.

[0085] The molten salt / reheat steam heat exchanger 12 is used to use low-temperature molten salt to perform heat exchange on the input reheat steam, so that the reheat steam is converted into low-temperature steam and the low-temperature molten salt is converted into high-temperature molten salt. In this embodiment, by transferring the heat of the reheat steam to the molten salt, the system can flexibly adjust the temperature of the reheat steam to meet the needs of power load fluctuations. The reheat steam is cooled by low-temperature molten salt and the heat energy is stored in the molten salt, so that excess heat energy can be stored when the power load is low, and released during peak hours to support the power peak load demand.

[0086] In this embodiment, the first valve device 10 is arranged on the first pipeline, and the second valve device 11 is arranged on the second pipeline. The first valve device 10 and the second valve device 11 are both controlled by the first control instruction, so that the extraction of a preset proportion of the high-pressure main steam in the first pipeline and the reheated steam in the second pipeline can be controlled for heat exchange with the molten salt.

[0087] In this embodiment, molten salt is used to store heat extracted from high-pressure main steam and reheated steam, and the heat energy of these steams is transferred to molten salt through a heat exchanger. After the low-temperature molten salt exchanges heat with steam through a heat exchanger, it becomes a high-temperature molten salt and is stored. Molten salt has a high specific heat capacity and can store heat for a long time. It has a strong heat storage capacity. The advantage of this is that excess heat energy can be stored when the power demand is low, and the heat can be released for power generation during peak hours, balancing the demand for heat energy. The molten salt heat storage and exchange system stores heat when the power demand is low, avoiding the necessity of continuous high-load operation of the boiler system. When the power demand is high, the heat energy stored in the molten salt can be released to supplement or increase the power generation load, realizing flexible peak shaving. The extraction and heat transfer of high-pressure main steam and reheated steam enable the system to quickly adapt to fluctuations in power demand and effectively support the peak shaving demand of the spot market. By extracting high-pressure steam and reheated steam during low-load periods and transferring them to the molten salt heat storage and exchange system, the system reduces the operation of the boiler at low loads and reduces the frequency of load fluctuations, thereby reducing the wear and thermal fatigue of the boiler superheater and reheater and extending the life of the equipment. In addition, this method avoids the thermal and mechanical stress caused by frequent start-ups and shutdowns, which helps to ensure long-term stable operation of the equipment.

[0088] In this embodiment, the temperature of the high-temperature main steam is 540-560°C. The molten salt in this embodiment is ternary nitrate, and its melting point is 142°C. The maximum operating temperature can reach 450-550°C. The temperature of the high-temperature molten salt obtained after heat exchange can reach above 400°C.

[0089] In one embodiment, the molten salt heat storage and exchange system is also used to return the converted liquid aqueous solution and low-temperature steam to the boiler system, and to store the converted high-temperature molten salt in the high-temperature molten salt storage tank 15.

[0090] In this embodiment, by returning the cooled aqueous solution and low-temperature steam to the boiler system, the system realizes the recycling of water resources and efficient management of steam energy, which helps to save water resources and maintain the stability of the boiler. The aqueous solution and low-temperature steam returned to the boiler can be heated again and converted into high-temperature and high-pressure steam, recycling the heat in the steam system, avoiding water resource waste, and reducing the boiler system's dependence on external water sources, thereby optimizing the entire power production process.

[0091] In this embodiment, high-temperature molten salt is stored in a high-temperature storage tank, which can efficiently store excess heat energy and facilitate its release during peak electricity demand, providing a stable heat energy reserve for peak-shaving operations. By storing high-temperature molten salt in a storage tank, the system can accumulate heat energy during low electricity consumption, ensuring sufficient heat energy supply during peak demand to support rapid response of power generation loads and improve the operational flexibility and economy of the power plant. This energy storage mode also reduces the idle waste of high-temperature heat sources, helps to extend the service life of molten salt and reduce operating costs.

[0092] Specifically, the salt outlet of the molten salt / main steam heat exchanger 13 and the salt outlet of the molten salt / reheat steam heat exchanger 12 are both connected to the salt inlet of the high-temperature molten salt storage tank 15;

[0093] In this embodiment, the high-temperature molten salt generated by the two heat exchangers (molten salt / main steam heat exchanger 13 and molten salt / reheat steam heat exchanger 12) is collected in the high-temperature molten salt storage tank 15, which effectively stores heat energy in a centralized manner, facilitates supply and utilization at any time, and improves the thermal energy management efficiency of the peak-shaving system. Storing high-temperature molten salt in a storage tank not only simplifies the structure of the energy storage system, but also provides efficient heat energy supply for power plants at different demand loads. The centralized high-temperature molten salt can be used for reheating when the power generation load is increased, realizing efficient energy management.

[0094] The water outlet of the liquid aqueous solution converted by the molten salt / main steam heat exchanger 13 is connected to the water supply port of the boiler superheater 1 in the boiler system;

[0095] In this embodiment, the liquid aqueous solution generated after heat exchange is directly transported back to the boiler superheater 1 as feed water, so as to realize the recycling of water resources, reduce the external water supply demand, and improve the water utilization efficiency of the system. The returned aqueous solution is already at a relatively high temperature state, and after re-entering the boiler, it can reduce the energy required for boiler heating, improve the boiler heating efficiency, reduce additional energy consumption, and reduce the overall operating cost.

[0096] The outlet of the low-temperature steam converted by the molten salt / reheat steam heat exchanger 12 is connected to the air inlet of the boiler reheater 2 .

[0097] In this embodiment, the low-temperature steam is returned to the boiler reheater 2 for subsequent heating, so that the residual heat of the steam can be reused, and the stability of the reheat steam cycle can be maintained, thereby enhancing the thermal energy utilization rate of the system.

[0098] After returning to the reheater 2, the low-temperature steam can be reheated to further increase its temperature and pressure to meet the operation requirements of the steam turbine. This cycle not only optimizes the use of boiler heat energy, but also reduces the demand for new steam, reduces energy waste, and improves the economy and environmental protection of the overall system.

[0099] The control system is further used to generate a second control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, and send the second control instruction to the molten salt heat storage and exchange system;

[0100] The molten salt heat storage and exchange system is used to use the pre-stored high-temperature molten salt to exchange heat with the condensed water generated by the steam turbine power generation system according to the second control instruction, so that the condensed water is converted into water vapor and the high-temperature molten salt is converted into low-temperature molten salt.

[0101] In this embodiment, by comparing the real-time electricity price with the preset electricity price, a second control instruction is generated, and the thermal energy stored in the molten salt can be used when the electricity price is high to convert the condensed water generated by the steam turbine back into steam for power generation. This approach can increase the power generation during periods of high electricity prices and improve revenue. In the electricity spot market, electricity prices fluctuate frequently. Using high-temperature molten salt heat storage to convert condensed water when the electricity price is high can generate electricity and sell electricity during periods of high demand, optimizing the revenue structure of the power plant and enhancing economic benefits.

[0102] In this embodiment, high-temperature molten salt is used to heat the condensed water of the steam turbine into water vapor, which is then used for power generation again. This can effectively utilize the heat energy cycle within the system, avoid direct heat discharge, and reduce energy waste. Condensed water is usually in a low-temperature and low-pressure state. By using the high-temperature heat energy of molten salt for secondary heating, it can be converted back into high-temperature and high-pressure steam for power generation, further recovering waste heat resources and improving the overall thermal efficiency of the system.

[0103] This control strategy in this embodiment enables the power plant to flexibly respond to the power market demand, adjust the power generation load according to the power price, realize peak load regulation, and alleviate the supply and demand fluctuations of the power system. The peak load regulation system adjusts the power generation load according to the real-time power price, ensuring that the output is increased during the high power price period and reduced during the low power price period, which not only balances the power grid load, but also reduces the cost loss caused by peak load regulation and increases the stability of the system.

[0104] In this embodiment, by using high-temperature molten salt to perform heat exchange on condensed water and lowering its temperature, the temperature of the molten salt can be lowered to a low temperature state, which is convenient for subsequent recycling and prolongs the life of the heat storage system. Using molten salt to heat condensed water can gradually lower its temperature, maintain the stable performance of the molten salt system, reduce material stress and chemical deterioration risks under high temperature conditions, and prolong the service life of the heat storage equipment.

[0105] In this embodiment, the molten salt heat storage and exchange system is also used to input the water vapor converted from the condensed water generated by the steam turbine power generation system into the steam turbine power generation system, and to store the converted low-temperature molten salt in the low-temperature molten salt storage tank 14.

[0106] In this embodiment, the water vapor converted from condensed water is re-input into the steam turbine power generation system, realizing secondary utilization and maximizing the power generation efficiency of the system. The water vapor converted from condensed water has enough energy to drive the steam turbine again. By recycling the generated water vapor, the effective working time of the steam turbine can be increased, thereby improving the overall power generation efficiency of the power plant.

[0107] In this embodiment, the low-temperature molten salt is returned to the low-temperature molten salt storage tank to achieve the temperature cycle of the molten salt, which helps to reduce the energy consumption in the cooling and heating process and reduce the overall energy consumption of the system. The molten salt becomes low temperature after using high temperature for heat exchange. After being centrally stored, it can be used again in subsequent heat exchange links, avoiding the use of new molten salt for heating and cooling each time, thereby saving energy and improving the sustainability of the system. Through the closed-loop circulation of molten salt and water vapor, not only the demand for the introduction of new resources is reduced, but also the emission risk is reduced, and the system can be kept stable for a long period of time. The recycling of molten salt and water vapor reduces the dependence of the thermal system on external substances, ensures the efficient operation of internal resources in the peak-shaving system, and helps maintain the long-term stability and reliability of the power plant.

[0108] The molten salt heat storage and exchange system further comprises: a molten salt / water heat exchanger 16;

[0109] The salt inlet of the molten salt / water heat exchanger 16 is connected to the salt outlet of the high-temperature molten salt storage tank 15;

[0110] The high-temperature molten salt storage tank 15 is also used to transfer the stored high-temperature molten salt to the molten salt / water heat exchanger 16 according to the second control instruction; the flow of molten salt is adjusted through the control instruction, responding to the fluctuation of market electricity price, and providing the load adjustment capability of the system. The system can flexibly transfer high-temperature molten salt according to the high or low electricity price, provide heat source for the heat exchanger, thereby increasing power generation during the peak period of electricity price and improving economic benefits.

[0111] The salt outlet of the molten salt / water heat exchanger 16 is connected to the salt inlet of the low-temperature molten salt storage tank 14;

[0112] In this embodiment, the low-temperature molten salt flows back to the low-temperature storage tank, which helps to efficiently recover and reuse resources, reduce system energy waste, and improve overall thermal efficiency.

[0113] The molten salt / water heat exchanger 16 is used to use high-temperature molten salt to perform heat exchange on the condensed water generated by the steam turbine power generation system, so that the condensed water is converted into water vapor and the high-temperature molten salt is converted into low-temperature molten salt. In this embodiment, the high-temperature molten salt converts the condensed water into water vapor, which can directly improve the output of the steam turbine and the power generation efficiency of the system; at the same time, the molten salt temperature is reduced and then flows back to the low-temperature storage tank, realizing a closed-loop circulation of resources, which helps to save heat sources and improve the continuous operation capability of the system.

[0114] This embodiment adds a molten salt / water heat exchanger so that the system can transfer the heat of the molten salt directly to the condensed water, which is more flexible and can adapt to more working conditions. The molten salt / water heat exchanger is specifically responsible for the heat exchange of the condensed water evaporation process, which can accurately control the heating process and optimize the operating efficiency of the system. The peak-shaving system of the thermal power plant based on the spot electricity transaction in this implementation realizes the direct transmission of high-temperature molten salt from the storage tank to the heat exchanger, providing sufficient heat for the heat exchanger. Sending high-temperature molten salt directly from the storage tank to the heat exchanger can reduce intermediate heat loss, maintain the stability of the high-temperature molten salt in the heat exchanger, and ensure the heat exchange effect.

[0115] The water inlet of the molten salt / water heat exchanger 16 is connected to the water outlet of the deaerator 8 for discharging condensed water in the steam turbine power generation system through a water pump.

[0116] When the molten salt heat storage and exchange system receives the second control instruction, the condensed water flowing out of the outlet of the deaerator 8 is pressurized by the feed water pump and sent to the molten salt / water heat exchanger 16 to exchange heat with the high-temperature molten salt in the high-temperature molten salt storage tank 15. After generating high-temperature and high-pressure steam, it is recycled to the low-pressure cylinder 5 of the thermal power unit to do work, or replace the steam extraction between the turbine stages to heat the feed water, thereby increasing the amount of steam for work and improving the unit output. After the high-temperature molten salt releases heat, it enters the low-temperature molten salt storage tank 14 for storage and is used for the next heating, thereby realizing the circulation and heat storage of the molten salt.

[0117] Condensed water has reached a certain temperature in the deaerator 8, and directly entering the heat exchanger helps maintain thermal energy continuity, reduce the impact of water temperature fluctuations on heat exchange efficiency, and improve the overall thermal efficiency of the system. The deoxygenated water has a low oxygen content, which helps reduce the risk of equipment oxidation and corrosion, and ensures the reliability and service life of the heat exchanger. The water pump provides stable flow and pressure control, avoiding fluctuations in the condensed water transmission process, thereby ensuring the continuity and efficiency of the system operation.

[0118] The high-temperature steam outlet of the molten salt / water heat exchanger 16 is connected to the low-pressure cylinder 5 in the steam turbine power generation system.

[0119] In this embodiment, by reusing the steam generated by the molten salt heat exchanger as a power source, the system utilizes the heat stored in the molten salt and converts it into mechanical energy, thereby efficiently utilizing thermal energy and increasing power generation. The molten salt heat storage system provides thermal energy by storing and releasing heat, and does not rely on direct combustion, thereby reducing the boiler's demand for fuel and achieving energy conservation and emission reduction. The steam temperature and flow provided by the molten salt heat exchanger are relatively stable, so the low-pressure cylinder obtains a more stable steam input, which is conducive to the smooth operation of the turbine and reduces the risk of failure.

[0120] The control system generates a first control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, which specifically includes:

[0121] When the real-time electricity price in the electricity spot market is lower than a preset value of the preset electricity price, a first control instruction is generated;

[0122] The control system generates a second control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, specifically including:

[0123] When the real-time electricity price in the electricity spot market is higher than a preset value of the preset electricity price, a second control instruction is generated.

[0124] In this embodiment, the control system monitors the real-time electricity price in the electricity spot market and compares it with the preset electricity price to generate corresponding control instructions. This function enables the system to flexibly adjust the operation strategy according to market price fluctuations.

[0125] When the real-time electricity price in the electricity spot market is lower than the preset value of the preset electricity price, the control system generates a first control instruction. This instruction may mean that when the electricity price is low, the system can choose to increase the consumption or generation of electricity. For example, more equipment may be enabled, the power generation output may be increased, or the energy storage system may be charged, because the low electricity price represents a more economical cost of purchasing electricity.

[0126] When the real-time electricity price in the electricity spot market is higher than the preset value of the preset electricity price, the control system generates a second control instruction. When the electricity price is high, the control system will choose to reduce the consumption or generation of electricity, or start the energy storage system to transmit electricity to the grid to obtain higher market price income. This helps to reduce operating costs or improve economic benefits.

[0127] By dynamically adjusting power consumption and production strategies, the control system can better respond to market changes and maximize economic benefits. For example, it can use cheap electricity during low-price periods to operate equipment and store energy, and then release electricity during high-price periods to gain benefits from price differences. This intelligent control system based on real-time data and preset values ​​improves the regulation capability of the power system, enabling it to optimize energy use and power generation strategies at different times and effectively respond to fluctuations in the power market.

[0128] Embodiment 2

[0129] A peak load regulation system for a thermal power plant based on power spot trading in this embodiment includes:

[0130] Boiler system: used to generate high-pressure main steam and reheat steam to supply the steam turbine power generation system.

[0131] Steam turbine power generation system: uses high-pressure steam generated by a boiler to generate electricity.

[0132] Control system: Generates control instructions based on the real-time electricity price and preset electricity price in the electricity spot market, and directs the operation of the molten salt heat storage and exchange system.

[0133] Molten salt heat storage and exchange system: used for heat exchange, specifically including molten salt / main steam heat exchanger, molten salt / reheat steam heat exchanger, valve device, and high-temperature and low-temperature molten salt storage tanks.

[0134] The working principle of the peak-shaving system of a thermal power plant based on spot electricity trading in this embodiment is as follows: when the electricity price in the spot electricity market is low, the control system generates a first control instruction to instruct the molten salt storage and heat exchange system to extract the high-pressure main steam and reheat steam generated by the boiler and exchange heat with the pre-stored low-temperature molten salt. Through the molten salt / main steam heat exchanger, the high-pressure main steam is converted into liquid water, and the molten salt is heated; through the molten salt / reheat steam heat exchanger, the reheat steam is converted into low-temperature steam, and the molten salt is heated at the same time. The converted liquid water and low-temperature steam flow back to the boiler system, and the molten salt is stored in a high-temperature molten salt storage tank. When the electricity price in the spot electricity market is higher than the preset electricity price, the control system generates a second control instruction to instruct the molten salt storage and heat exchange system to use the stored high-temperature molten salt to exchange heat with the condensed water generated by the steam turbine power generation system, so that the condensed water is converted into water vapor, and the molten salt is cooled at the same time. In this way, the boiler can continue to operate efficiently.

[0135] The peak load regulation system can achieve the following: store heat when electricity prices are low, reducing electricity production costs during peak hours. Dynamically adjust power generation and heat exchange strategies based on real-time electricity prices to ensure maximum benefits during high electricity price moments. Help the power grid cope with load fluctuations and improve the stability of the power system.

[0136] The thermal power plant peak-shaving system based on electricity spot trading in this embodiment combines the price information of the real-time electricity market, optimizes the operation mode of the thermal power plant through efficient heat exchange and storage strategies, and improves the economic benefits and flexibility of the power system.

[0137] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0138] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0139] In the present invention, unless otherwise clearly specified and limited, when a first feature is “on” or “below” a second feature, it may be that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, when a first feature is “above”, “above” or “above” a second feature, it may be that the first feature is directly above or obliquely above the second feature, or it may simply mean that the first feature is higher in level than the second feature. When a first feature is “below”, “below” or “below” a second feature, it may be that the first feature is directly below or obliquely below the second feature, or it may simply mean that the first feature is lower in level than the second feature.

[0140] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0141] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A peak-shaving system for a thermal power plant based on spot electricity trading, the peak-shaving system comprising a boiler system for generating high-pressure main steam and reheated steam in a production process and a steam turbine power generation system for generating electricity based on the high-pressure main steam generated by the boiler system, characterized in that: The peak shaving system further comprises: A control system, configured to generate a first control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, and send the first control instruction to the molten salt heat storage and exchange system; The molten salt heat storage and exchange system is used to extract the high-pressure main steam and reheated steam generated by the boiler system according to the first control instruction, and exchange heat with the pre-stored low-temperature molten salt respectively, so that the extracted high-pressure main steam generated by the boiler system is converted into a liquid aqueous solution, the reheated steam is converted into low-temperature steam, and the low-temperature molten salt is converted into a high-temperature molten salt.

2. The peak load regulation system of a thermal power plant based on spot electricity trading according to claim 1 is characterized in that: The molten salt heat storage and exchange system comprises: a molten salt / main steam heat exchanger (13), a molten salt / reheat steam heat exchanger (12), and a first valve device (10), a second valve device (11), a high-temperature molten salt storage tank (15), and a low-temperature molten salt storage tank (14) respectively connected to the control system; The first valve device (10) is arranged on the first pipeline and connected to the air inlet of the molten salt / main steam heat exchanger (13), and is used to extract high-pressure main steam in the first pipeline and transport it to the molten salt / main steam heat exchanger (13) according to the first control instruction; The first pipeline is a pipeline for high-pressure main steam generated by a boiler superheater (1) in a boiler system to enter a high-pressure cylinder (3) in a steam turbine power generation system; The second valve device (11) is arranged on the second pipeline and connected to the air inlet of the molten salt / reheat steam heat exchanger (12), and is used to extract the reheat steam in the second pipeline and transport it to the molten salt / reheat steam heat exchanger (12) according to the first control instruction; The second pipeline is a pipeline for the reheated steam generated by the boiler reheater (2) in the boiler system to enter the intermediate pressure cylinder (4) in the steam turbine power generation system; The salt outlet of the low-temperature molten salt storage tank (14) is respectively connected to the salt inlet of the molten salt / main steam heat exchanger (13) and the salt inlet of the molten salt / reheat steam heat exchanger (12), and is used to transmit the stored low-temperature molten salt to the molten salt / main steam heat exchanger (13) and the molten salt / reheat steam heat exchanger (12) respectively according to the first control instruction; The molten salt / main steam heat exchanger (13) is used to use low-temperature molten salt to perform heat exchange on the input high-pressure main steam, so that the high-pressure main steam is converted into a liquid aqueous solution and the low-temperature molten salt is converted into a high-temperature molten salt; The molten salt / reheat steam heat exchanger (12) is used to use low-temperature molten salt to perform heat exchange on the input reheat steam, so that the reheat steam is converted into low-temperature steam and the low-temperature molten salt is converted into high-temperature molten salt.

3. The peak load regulation system of a thermal power plant based on spot electricity trading according to claim 2 is characterized in that: The molten salt heat storage and exchange system is also used to return the converted liquid aqueous solution and low-temperature steam to the boiler system, and to store the converted high-temperature molten salt in a high-temperature molten salt storage tank (15).

4. The peak load regulation system of a thermal power plant based on spot electricity trading according to claim 3 is characterized in that: The salt outlet of the molten salt / main steam heat exchanger (13) and the salt outlet of the molten salt / reheat steam heat exchanger (12) are both connected to the salt inlet of the high-temperature molten salt storage tank (15); The water outlet of the liquid aqueous solution converted by the molten salt / main steam heat exchanger (13) is connected to the water supply port of the boiler superheater (1) in the boiler system; The outlet of the low-temperature steam converted by the molten salt / reheat steam heat exchanger (12) is connected to the air inlet of the boiler reheater (2).

5. The peak load regulation system of thermal power plant based on power spot trading according to claim 3 is characterized in that: The control system is further used to generate a second control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, and send the second control instruction to the molten salt heat storage and exchange system; The molten salt heat storage and exchange system is used to use the pre-stored high-temperature molten salt to exchange heat with the condensed water generated by the steam turbine power generation system according to the second control instruction, so that the condensed water is converted into water vapor and the high-temperature molten salt is converted into low-temperature molten salt.

6. The peak load regulation system of thermal power plant based on power spot trading according to claim 5 is characterized in that: The molten salt heat storage and exchange system is also used to input water vapor converted from condensed water generated by the steam turbine power generation system into the steam turbine power generation system, and to store the converted low-temperature molten salt in a low-temperature molten salt storage tank (14).

7. The peak load regulation system of thermal power plant based on power spot trading according to claim 6 is characterized in that: The molten salt heat storage and exchange system further comprises: a molten salt / water heat exchanger (16); The salt inlet of the molten salt / water heat exchanger (16) is connected to the salt outlet of the high-temperature molten salt storage tank (15); The high-temperature molten salt storage tank (15) is also used to transfer the stored high-temperature molten salt to the molten salt / water heat exchanger (16) according to a second control instruction; The salt outlet of the molten salt / water heat exchanger (16) is connected to the salt inlet of the low-temperature molten salt storage tank (14); The molten salt / water heat exchanger (16) is used to use high-temperature molten salt to perform heat exchange on condensed water generated by the steam turbine power generation system, so that the condensed water is converted into water vapor and the high-temperature molten salt is converted into low-temperature molten salt.

8. The peak load regulation system of thermal power plant based on electricity spot trading according to claim 7 is characterized in that: The water inlet of the molten salt / water heat exchanger (16) is connected to the water outlet of the deaerator (8) for discharging condensed water in the steam turbine power generation system via a water pump.

9. The peak load regulation system of thermal power plants based on electricity spot trading according to claim 8 is characterized in that: The high-temperature steam outlet of the molten salt / water heat exchanger (16) is connected to the low-pressure cylinder (5) in the steam turbine power generation system.

10. The peak load regulation system of thermal power plant based on power spot trading according to claim 8, characterized in that: in, The control system generates a first control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, which specifically includes: When the real-time electricity price in the electricity spot market is lower than a preset value of the preset electricity price, a first control instruction is generated; The control system generates a second control instruction according to the acquired real-time electricity price and preset electricity price in the electricity spot market, specifically including: When the real-time electricity price in the electricity spot market is higher than a preset value of the preset electricity price, a second control instruction is generated.

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