Fused salt heat storage and turbine steam supplement coupled peak regulation power generation system and method

Abstract

The invention provides a peak regulation power generation system and method coupling fused salt heat storage and steam supplementing of a steam turbine, and relates to the technical field of heat energy engineering.The system comprises a fused salt heat storage and heat exchange system comprising a low-temperature fused salt tank, a fused salt heater, a high-temperature fused salt tank and a fused salt steam-water heat exchanger; comprising a gas-fired boiler, a steam turbine and a water supply system; the fused salt heater is used for receiving low-temperature fused salt fed by the low-temperature fused salt tank through the low-temperature fused salt pump in the electricity utilization trough period and heating the low-temperature fused salt through heat provided by the gas-fired boiler. The fused salt steam-water heat exchanger is used for receiving high-temperature fused salt fed by the high-temperature fused salt tank through the high-temperature fused salt pump during the peak period of electricity consumption and transferring heat energy of the high-temperature fused salt to high-pressure feed water from the water supply system to generate superheated steam; and one part of the superheated steam is fed into a main steam main pipe connected with the gas-fired boiler. The power generation efficiency of the steam turbine can be effectively improved, and efficient utilization of heat energy and flexible adjustment of power grid loads are achieved.

Description

Technical Field

[0001] The present application relates to the field of thermal energy engineering technology, and in particular to a peak-shaving power generation system and method that couples molten salt heat storage with steam turbine supplementation. Background Art

[0002] With rapid economic development and accelerating industrialization, the contradiction between energy shortages and high energy consumption is becoming increasingly prominent. Energy storage is a key supporting technology for the energy revolution and a means to address the large-scale integration of renewable energy, improve the efficiency of power and regional energy systems, and enhance safety and cost-effectiveness.

[0003] Molten salt heat storage offers advantages such as a wide temperature range, large heat capacity, and high heat exchange efficiency. It can deliver stored heat energy to thermal power generation equipment in a clean, efficient, and flexible manner. In power system operation, deep peak shaving is crucial for ensuring grid stability and efficient energy utilization. Currently, molten salt heat storage technology is being applied to deep peak shaving of generator sets. This technology uses molten salt electric heaters to heat the molten salt to quickly respond to peak shaving demands, and a molten salt cooling system transfers the heat energy to the generator feed water. This technology features self-condensation protection, with no phase transition between hot and cold media. Leveraging existing high-efficiency steam turbine generator sets, it can reduce heat consumption, achieving high-capacity, long-term, highly safe, and low-cost deep peak shaving.

[0004] However, the existing deep peak-shaving scheme for power generation units based on molten salt heat storage has obvious shortcomings, among which the mismatch between the molten salt heat release system and the steam production parameters of the power generation units is particularly prominent. This limits the further optimization and development of this technology in practical applications, and innovative technical solutions are urgently needed to solve related problems. Summary of the Invention

[0005] In response to the problems in the prior art, the embodiments of the present application provide a peak-shaving power generation system and method that couples molten salt heat storage with steam turbine supplementation, which can solve the problems in the prior art.

[0006] In a first aspect, the present application provides a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation, comprising: a molten salt heat storage and heat exchange system and a steam-water circulation system;

[0007] The molten salt heat storage and heat exchange system includes a low-temperature molten salt tank, a molten salt heater, a high-temperature molten salt tank and a molten salt steam-water heat exchanger;

[0008] The steam-water circulation system includes a gas boiler, a steam turbine and a water supply system; the steam turbine includes a high-pressure cylinder and a medium- and low-pressure cylinder;

[0009] The molten salt heater is used to receive the low-temperature molten salt fed into the low-temperature molten salt tank through the low-temperature molten salt pump during the off-peak period of electricity consumption, and heat the low-temperature molten salt with the heat provided by the gas boiler;

[0010] The high-temperature molten salt tank is connected to the molten salt heater and is used to receive and store the heated molten salt;

[0011] The molten salt steam-water heat exchanger is used to receive the high-temperature molten salt fed into the high-temperature molten salt tank by the high-temperature molten salt pump during peak electricity consumption, and transfer the heat energy of the high-temperature molten salt to the high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler;

[0012] The low-temperature molten salt tank is connected to the molten salt steam-water heat exchanger and is used to receive and store the molten salt after heat exchange.

[0013] Furthermore, another portion of the superheated steam is fed into the middle stage of the high-pressure cylinder and the middle stage of the medium- and low-pressure cylinders.

[0014] Furthermore, it also includes: a first-stage desuperheater and a second-stage desuperheater and a pressure reducer;

[0015] The first-stage desuperheater is connected to the molten salt steam-water heat exchanger and the high-pressure cylinder, and is used to perform a first desuperheating and pressure reduction on the received superheated steam, and then send a portion of the superheated steam after the first desuperheating and pressure reduction to the middle stage of the high-pressure cylinder;

[0016] The secondary desuperheater and pressure reducer is connected to the primary desuperheater and pressure reducer and the intermediate and low pressure cylinders, and is used to perform secondary desuperheating and pressure reduction on another portion of the superheated steam after the primary desuperheating and pressure reduction, and then send the steam into the middle stage of the intermediate and low pressure cylinders.

[0017] Furthermore, the steam-water circulation system further comprises: a condenser;

[0018] The condenser is connected to the intermediate and low pressure cylinders and the water supply system, and is used for condensing the exhaust gas of the intermediate and low pressure cylinders into condensed water and transporting the condensed water to the water supply system through a condensate pump.

[0019] Furthermore, the water supply system includes: a low-pressure heater, a deaerator and a high-pressure heater;

[0020] The low-pressure heater is connected to the deaerator and is used to heat the condensate using the heat of the steam extracted from the medium and low-pressure cylinders, and to transport the obtained preheated water to the deaerator;

[0021] The deaerator is connected to the high-pressure heater and is used to deoxygenate the preheated water by utilizing the heat of the steam extracted from the medium and low-pressure cylinders, and to pressurize the obtained deoxygenated water through the feed water pump and then deliver it to the high-pressure heater;

[0022] The high-pressure heater is connected to the gas boiler and the molten salt steam-water heat exchanger, and is used to use the heat of the high-pressure cylinder extraction steam to further heat the pressurized deoxygenated water, and to transport the obtained high-pressure feed water to the gas boiler and the molten salt steam-water heat exchanger.

[0023] Furthermore, another portion of the superheated steam is fed into the high-pressure heater and the low-pressure heater as a steam heat source.

[0024] Furthermore, it also includes: a first-stage desuperheater and a second-stage desuperheater and a pressure reducer;

[0025] The first-stage desuperheater is connected to the molten salt steam-water heat exchanger and the high-pressure heater, and is used to perform a first desuperheating and pressure reduction on the received superheated steam, and then send a portion of the superheated steam after the first desuperheating and pressure reduction into the high-pressure heater;

[0026] The secondary desuperheater and pressure reducer is connected to the primary desuperheater and pressure reducer and the low-pressure heater, and is used to perform secondary desuperheating and pressure reduction on another portion of the superheated steam after the primary desuperheating and pressure reduction, and then send the steam into the low-pressure heater.

[0027] Furthermore, a steam bypass channel is provided between the molten salt steam-water heat exchanger and the gas boiler, and a flow limiting valve is provided on the steam bypass channel, and the flow limiting valve is used to limit the maximum flow of molten salt steam entering the main steam main pipe.

[0028] Furthermore, the maximum flow rate does not exceed 30% of the main steam flow rate.

[0029] In a second aspect, the present application provides a peak-shaving power generation method coupled with molten salt heat storage and steam turbine supplementation, which is applied to the peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation described in any of the above embodiments, comprising:

[0030] The molten salt heater receives the low-temperature molten salt fed into the low-temperature molten salt tank through the low-temperature molten salt pump during the off-peak period of electricity consumption, and heats the low-temperature molten salt with the heat provided by the gas boiler;

[0031] The high-temperature molten salt tank receives and stores the heated molten salt;

[0032] The molten salt steam-water heat exchanger receives the high-temperature molten salt fed into the high-temperature molten salt tank by the high-temperature molten salt pump during peak electricity consumption, and transfers the heat energy of the high-temperature molten salt to the high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler;

[0033] The low-temperature molten salt tank receives and stores the molten salt after heat exchange.

[0034] The present application provides a peak-shaving power generation system and method coupled with molten salt heat storage and steam turbine supplementation, the system comprising: a molten salt heat storage and heat exchange system and a steam-water circulation system; the molten salt heat storage and heat exchange system comprising a low-temperature molten salt tank, a molten salt heater, a high-temperature molten salt tank and a molten salt steam-water heat exchanger; the steam-water circulation system comprising a gas boiler, a steam turbine and a water supply system; the molten salt heater is configured to receive low-temperature molten salt fed into the low-temperature molten salt tank via a low-temperature molten salt pump during off-peak hours, and heat the low-temperature molten salt using heat provided by the gas boiler; the high-temperature molten salt tank is connected to the molten salt heater and is configured to receive and store the heated molten salt; the molten salt steam-water heat exchanger is configured to receive high-temperature molten salt fed into the high-temperature molten salt tank via a high-temperature molten salt pump during peak hours, and transfer the heat energy of the high-temperature molten salt to high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into a main steam main pipe connected to the gas boiler; the low-temperature molten salt tank is connected to the molten salt steam-water heat exchanger and is configured to receive and store the molten salt after heat exchange. The peak-shaving power generation system and method coupled with molten salt heat storage and steam turbine supplementation provided in the present application effectively improve the power generation efficiency of the steam turbine, reduce the dependence on steam extraction, and achieve efficient utilization of thermal energy and flexible regulation of grid load.

[0035] Among them, the thermal energy storage of coal gas during off-peak periods is used to adapt to the price difference of industrial electricity and realize economic peak regulation; during peak periods, molten salt steam is used to supplement steam or connect steam to the turbine to increase the power generation capacity; the steam is accurately adjusted to the middle cylinder section by using a temperature and pressure reducer to ensure the stable operation of the turbine; the strategy of limiting the steam flow rate and the main pipe ratio is adopted to control the thermal disturbance range of the main pipe; molten salt steam is used instead of extraction steam for feed water heating to reduce extraction steam loss and improve work capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 This is a structural diagram of a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application;

[0038] Figure 2 This is a structural diagram of a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application;

[0039] Figure 3 This is a structural diagram of a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application;

[0040] Figure 4 It is a flow chart of a peak-shaving power generation method coupling molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application. DETAILED DESCRIPTION

[0041] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clearly understood, the embodiments of the present application are further described in detail below with reference to the accompanying drawings. The illustrative embodiments of the present application and their descriptions are used to explain the present application but are not intended to limit the present application. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present application may be combined with each other in any manner.

[0042] Figure 1 This is a schematic diagram of the structure of a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application. Figure 1 As shown, the peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplement provided by the present application includes: a molten salt heat storage and heat exchange system and a steam-water circulation system;

[0043] The molten salt heat storage and heat exchange system includes a low-temperature molten salt tank 11, a molten salt heater 10, a high-temperature molten salt tank 12 and a molten salt steam-water heat exchanger 9;

[0044] The steam-water circulation system includes a gas boiler 1, a steam turbine and a water supply system; the steam turbine includes a high-pressure cylinder 21 and a medium- and low-pressure cylinder 22;

[0045] The molten salt heater 10 is used to receive the low-temperature molten salt sent by the low-temperature molten salt tank 11 through the low-temperature molten salt pump 13 during the off-peak period of electricity consumption, and heat the low-temperature molten salt with the heat provided by the gas boiler 1;

[0046] The high-temperature molten salt tank 12 is connected to the molten salt heater 10 and is used to receive and store the heated molten salt;

[0047] The molten salt steam-water heat exchanger 9 is used to receive the high-temperature molten salt fed into the high-temperature molten salt tank 12 via the high-temperature molten salt pump 14 during peak electricity consumption hours, and transfer the heat energy of the high-temperature molten salt to the high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler 1;

[0048] The low-temperature molten salt tank 11 is connected to the molten salt steam-water heat exchanger 9 and is used to receive and store the molten salt after heat exchange.

[0049] Specifically, during periods of low electricity consumption, the molten salt in the low-temperature molten salt tank 11 is pumped into the molten salt heater 10 via the low-temperature molten salt pump 13. The heated high-temperature molten salt is then stored in the high-temperature molten salt tank 12, completing the heat storage process. During peak electricity consumption, the high-temperature molten salt in the high-temperature molten salt tank 12 is pumped into the molten salt steam-water heat exchanger 9 via the high-temperature molten salt pump 14. After exchanging heat with the boiler feed water and cooling it, the low-temperature molten salt is then stored in the low-temperature molten salt tank 11, completing the heat release process.

[0050] During off-peak hours, the steam-water circulation system operates in the same manner as the existing steam turbine generator set. During peak hours, a portion of the steam generated by the molten salt heat release is fed into the main steam header connected to gas boiler 1, increasing the flow of new steam for steam turbine power generation.

[0051] In one embodiment, if Figure 1 As shown, another part of the superheated steam is sent to the middle stage of the high-pressure cylinder 21 and the middle stage of the medium- and low-pressure cylinders 22.

[0052] Specifically, another part of the steam generated by the molten salt heat release is fed into the middle stage of the high-pressure cylinder 21 and the middle stage of the medium- and low-pressure cylinder 22 of the steam turbine as steam supplement to increase the power generation of the steam turbine generator set during peak power consumption periods.

[0053] In one embodiment, if Figure 1 As shown, the peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplement provided by the present application further includes: a first-stage desuperheater and pressure reducer 15 and a second-stage desuperheater and pressure reducer 16;

[0054] The first-stage desuperheater 15 is connected to the molten salt steam-water heat exchanger 9 and the high-pressure cylinder 21, and is used to perform a first desuperheating and pressure reduction on the received superheated steam, and then send a portion of the superheated steam after the first desuperheating and pressure reduction into the middle stage of the high-pressure cylinder 21;

[0055] The secondary desuperheater 16 is connected to the primary desuperheater 15 and the intermediate and low pressure cylinders 22 , and is used to perform secondary desuperheating and decompression on another portion of the superheated steam after the primary desuperheating and decompression, and then send the steam into the middle stage of the intermediate and low pressure cylinders 22 .

[0056] Specifically, the high-pressure feed water generates superheated steam after heat exchange with the molten salt in the molten salt steam-water heat exchanger 9. Part of the superheated steam is introduced into the main steam main pipe connected to the gas boiler 1, and the other part is introduced into the middle stage of the high-pressure cylinder 21 of the steam turbine after being cooled and reduced in pressure by the first-stage temperature reducer 15, and is used as steam supply to the high-pressure cylinder 21; and the other part is introduced into the middle stage of the medium and low-pressure cylinders 22 of the steam turbine after being cooled and reduced in pressure by the second-stage temperature reducer 16, and is used as steam supply to the medium and low-pressure cylinders 22.

[0057] In one embodiment, if Figure 1 As shown, the steam-water circulation system further includes: a condenser 3;

[0058] The condenser 3 is connected to the intermediate and low pressure cylinders 22 and the water supply system, and is used to condense the exhaust gas of the intermediate and low pressure cylinders 22 into condensed water and transport the condensed water to the water supply system through a condensate pump 4.

[0059] In one embodiment, if Figure 1 As shown, the water supply system includes: a low-pressure heater 5, a deaerator 6 and a high-pressure heater 8;

[0060] The low-pressure heater 5 is connected to the deaerator 6 and is used to heat the condensate using the heat of the steam extracted from the medium- and low-pressure cylinders 22, and to transport the obtained preheated water to the deaerator 6;

[0061] The deaerator 6 is connected to the high-pressure heater 8 and is used to deoxygenate the preheated water by utilizing the heat of the steam extracted from the medium and low-pressure cylinders 22, and the obtained deoxygenated water is pressurized by the water feed pump 7 and then transported to the high-pressure heater 8;

[0062] The high-pressure heater 8 is connected to the gas boiler 1 and the molten salt steam-water heat exchanger 9, and is used to use the heat of the steam extracted from the high-pressure cylinder 21 to further heat the pressurized deoxygenated water, and to transport the obtained high-pressure feed water to the gas boiler 1 and the molten salt steam-water heat exchanger 9.

[0063] Specifically, the exhaust steam from the low-pressure cylinder of the steam turbine enters the condenser 3 and condenses into condensate, which is then sent to the low-pressure heater 5 and the deaerator 6 in sequence by the condensate pump 4. The deoxygenated low-pressure feed water is sent to the high-pressure heater 8 through the feed water pump 7. After being heated by the high-pressure heater 8, part of the high-pressure feed water enters the gas boiler 1, and the other part enters the molten salt steam-water heat exchanger 9, completing the steam-water cycle.

[0064] The heating steam for the high-pressure heater 8, the deaerator 6 and the low-pressure heater 5 comes from the extraction steam from the high-pressure cylinder 21 and the medium- and low-pressure cylinders 22 of the steam turbine respectively.

[0065] Figure 2 This is a schematic diagram of the structure of a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application. Figure 2 As shown, another part of the superheated steam is sent to the high-pressure heater 8 and the low-pressure heater 5 as a steam heat source.

[0066] In one embodiment, if Figure 2 As shown, it also includes: a first-stage desuperheater and pressure reducer 15 and a second-stage desuperheater and pressure reducer 16;

[0067] The primary desuperheater 15 is connected to the molten salt steam-water heat exchanger 9 and the high-pressure heater 8, and is used to perform a primary desuperheating and decompression on the received superheated steam, and then send a portion of the superheated steam after the primary desuperheating and decompression into the high-pressure heater 8;

[0068] The secondary desuperheater 16 is connected to the primary desuperheater 15 and the low-pressure heater 5 and is used to perform secondary desuperheating and decompression on another portion of the superheated steam after the primary desuperheating and decompression and then send the steam to the low-pressure heater 5 .

[0069] Specifically, part of the superheated steam generated by the molten salt steam-water heat exchanger 9 is introduced into the main steam main pipe generated by the boiler, and the other part is introduced into the high-pressure cylinder 21 of the steam turbine for extraction after being cooled and reduced in pressure by the first-stage temperature reducer 15, and is used as heating steam for the high-pressure heater 8. The second part is introduced into the medium- and low-pressure cylinders 22 of the steam turbine for extraction after being cooled and reduced in pressure by the second-stage temperature reducer 16, and is used as heating steam for the low-pressure heater 5, thereby reducing the steam extraction of the steam turbine, increasing the amount of steam involved in the work of the steam turbine, and improving the power generation capacity of the steam turbine during peak hours of electricity consumption.

[0070] In one embodiment, if Figure 3 As shown, part of the superheated steam generated by the molten salt steam-water heat exchanger 9 is fed into the main steam header generated by the boiler, and the other part completely replaces the steam extracted from the steam turbine as heating steam for the high-pressure heater 8 and the low-pressure heater 5.

[0071] In one embodiment, a steam bypass channel is provided between the molten salt steam-water heat exchanger 9 and the gas boiler 1 , and a flow limiting valve is provided on the steam bypass channel, which is used to limit the maximum flow of molten salt steam entering the main steam main pipe.

[0072] In one embodiment, the maximum flow rate does not exceed 30% of the main steam flow rate.

[0073] Specifically, a high-pressure steam bypass channel with controllable on / off is provided before the superheated steam generated by the molten salt steam-water heat exchanger 9 is merged into the main steam main pipe connected to the gas boiler 1, so as to control the molten salt heat release steam production flow rate to be less than 30% of the steam main pipe flow rate, thereby ensuring that the temperature change of the steam main pipe is less than ±5°C after the molten salt heat release steam production flow rate is merged into the main pipe.

[0074] This application utilizes the heat energy generated by gas combustion during periods of low electricity prices to heat molten salt, stores it in the form of heat energy in a high-temperature molten salt storage tank, and releases the energy during peak electricity consumption periods, increasing the supply of electricity or steam. This is beneficial to regional power grid load regulation, improving energy utilization, and has good social benefits. Combining the steam generated by the molten salt heat release with the steam generated by the generator boiler through a main pipe can reduce the impact of the mismatch between the two steam parameters on the steam turbine; at the same time, the steam generated by the molten salt heat release is cooled and decompressed and then incorporated into the intermediate stage of the steam turbine, or replaces the steam extraction of the steam turbine, which can increase the power generation of the steam turbine during peak electricity periods and ensure the matching of the steam generated by the molten salt heat release with the steam turbine, making the system more efficient, stable, and reliable.

[0075] The present application provides a peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation, the system comprising: a molten salt heat storage and heat exchange system and a steam-water circulation system; the molten salt heat storage and heat exchange system comprising a low-temperature molten salt tank, a molten salt heater, a high-temperature molten salt tank and a molten salt steam-water heat exchanger; the steam-water circulation system comprising a gas boiler, a steam turbine and a water supply system; the molten salt heater is configured to receive low-temperature molten salt fed into the low-temperature molten salt tank via a low-temperature molten salt pump during off-peak hours, and heat the low-temperature molten salt using heat provided by the gas boiler; the high-temperature molten salt tank is connected to the molten salt heater and is configured to receive and store the heated molten salt; the molten salt steam-water heat exchanger is configured to receive high-temperature molten salt fed into the high-temperature molten salt tank via a high-temperature molten salt pump during peak hours, and transfer the heat energy of the high-temperature molten salt to high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into a main steam main pipe connected to the gas boiler; the low-temperature molten salt tank is connected to the molten salt steam-water heat exchanger and is configured to receive and store the molten salt after heat exchange. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation provided in this application effectively improves the power generation efficiency of the steam turbine, reduces dependence on steam extraction, and realizes efficient utilization of thermal energy and flexible regulation of grid load.

[0076] Among them, the thermal energy storage of coal gas during off-peak periods is used to adapt to the price difference of industrial electricity and realize economic peak regulation; during peak periods, molten salt steam is used to supplement steam or connect steam to the turbine to increase the power generation capacity; the steam is accurately adjusted to the middle cylinder section by using a temperature and pressure reducer to ensure the stable operation of the turbine; the strategy of limiting the steam flow rate and the main pipe ratio is adopted to control the thermal disturbance range of the main pipe; molten salt steam is used instead of extraction steam for feed water heating to reduce extraction steam loss and improve work capacity.

[0077] Figure 4 This is a flow chart of a peak-shaving power generation method coupled with molten salt heat storage and steam turbine supplementation provided in one embodiment of the present application, such as Figure 4 As shown, the peak-shaving power generation method provided by the present application that couples molten salt heat storage with steam turbine supplementation includes:

[0078] S401: The molten salt heater receives the low-temperature molten salt delivered from the low-temperature molten salt tank through the low-temperature molten salt pump during the off-peak period of electricity consumption, and heats the low-temperature molten salt with the heat provided by the gas boiler;

[0079] S402: The high-temperature molten salt tank receives and stores the heated molten salt;

[0080] S403: The molten salt steam-water heat exchanger receives high-temperature molten salt fed from the high-temperature molten salt tank via the high-temperature molten salt pump during peak electricity consumption, and transfers heat energy of the high-temperature molten salt to high-pressure feed water from the water feed system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler;

[0081] S404: The low-temperature molten salt tank receives and stores the molten salt after heat exchange.

[0082] Specifically, during periods of low electricity consumption, the molten salt in the low-temperature molten salt storage tank is pumped into the molten salt heater via a low-temperature molten salt pump. The heated high-temperature molten salt is then stored in the high-temperature molten salt storage tank, completing the heat storage process. During peak electricity consumption periods, the high-temperature molten salt in the high-temperature molten salt storage tank is pumped into the molten salt steam-water heat exchanger via a high-temperature molten salt pump. After heat exchange with boiler feed water and cooling, the low-temperature molten salt is then stored in the low-temperature molten salt storage tank, completing the heat release process.

[0083] During peak electricity consumption periods, part of the steam produced by molten salt heat release is fed into the main steam pipe of the gas boiler to increase the new steam flow for turbine power generation, and the other part is used as steam supplement for the turbine to increase the power generation of the turbine generator set during peak electricity consumption periods, or as heating steam for high-pressure heaters and low-pressure heaters, thereby reducing steam extraction from the turbine, increasing the amount of steam involved in the work of the turbine, and improving the power generation capacity of the turbine during peak electricity consumption periods.

[0084] This application utilizes the heat energy generated by gas combustion during periods of low electricity prices to heat molten salt, stores it in the form of heat energy in a high-temperature molten salt storage tank, and releases the energy during peak electricity consumption periods, increasing the supply of electricity or steam. This is beneficial to regional power grid load regulation, improving energy utilization, and has good social benefits. Combining the steam generated by the molten salt heat release with the steam generated by the generator boiler through a main pipe can reduce the impact of the mismatch between the two steam parameters on the steam turbine; at the same time, the steam generated by the molten salt heat release is cooled and decompressed and then incorporated into the intermediate stage of the steam turbine, or replaces the steam extraction of the steam turbine, which can increase the power generation of the steam turbine during peak electricity periods and ensure the matching of the steam generated by the molten salt heat release with the steam turbine, making the system more efficient, stable, and reliable.

[0085] The present application provides a peak-shaving power generation method that couples molten salt heat storage with steam supplement to a steam turbine. The molten salt heater receives the low-temperature molten salt delivered by the low-temperature molten salt tank through a low-temperature molten salt pump during a low-power consumption period, and heats the low-temperature molten salt through the heat provided by the gas boiler; the high-temperature molten salt tank receives and stores the heated molten salt; the molten salt steam-water heat exchanger receives the high-temperature molten salt delivered by the high-temperature molten salt tank through a high-temperature molten salt pump during a peak power consumption period, and transfers the heat energy of the high-temperature molten salt to the high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler; the low-temperature molten salt tank receives and stores the molten salt after heat exchange, thereby effectively improving the power generation efficiency of the steam turbine, reducing dependence on steam extraction, and realizing efficient utilization of thermal energy and flexible adjustment of the grid load.

[0086] Among them, the thermal energy storage of coal gas during off-peak periods is used to adapt to the price difference of industrial electricity and realize economic peak regulation; during peak periods, molten salt steam is used to supplement steam or connect steam to the turbine to increase the power generation capacity; the steam is accurately adjusted to the middle cylinder section by using a temperature and pressure reducer to ensure the stable operation of the turbine; the strategy of limiting the steam flow rate and the main pipe ratio is adopted to control the thermal disturbance range of the main pipe; molten salt steam is used instead of extraction steam for feed water heating to reduce extraction steam loss and improve work capacity.

[0087] In the description of this specification, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "multiple" means two or more.

[0088] The descriptions with reference to the terms "one embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples" mean 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 application. 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 a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present application, and the order of steps therein is not limited and can be appropriately adjusted as needed.

[0089] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0090] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A peak-shaving power generation system coupling molten salt heat storage and steam turbine supplementation, characterized in that: include: Molten salt heat storage and heat exchange system and steam-water circulation system; The molten salt heat storage and heat exchange system includes a low-temperature molten salt tank, a molten salt heater, a high-temperature molten salt tank and a molten salt steam-water heat exchanger; The steam-water circulation system includes a gas boiler, a steam turbine and a water supply system; the steam turbine includes a high-pressure cylinder and a medium- and low-pressure cylinder; The molten salt heater is used to receive the low-temperature molten salt fed into the low-temperature molten salt tank through the low-temperature molten salt pump during the off-peak period of electricity consumption, and heat the low-temperature molten salt with the heat provided by the gas boiler; The high-temperature molten salt tank is connected to the molten salt heater and is used to receive and store the heated molten salt; The molten salt steam-water heat exchanger is used to receive the high-temperature molten salt fed into the high-temperature molten salt tank by the high-temperature molten salt pump during peak electricity consumption, and transfer the heat energy of the high-temperature molten salt to the high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler; The low-temperature molten salt tank is connected to the molten salt steam-water heat exchanger and is used to receive and store the molten salt after heat exchange.

2. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 1 is characterized in that: Another portion of the superheated steam is fed into the middle stage of the high-pressure cylinder and the middle stage of the medium- and low-pressure cylinders.

3. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 2 is characterized in that: Also includes: First-stage desuperheater and pressure reducer and second-stage desuperheater and pressure reducer; The first-stage desuperheater is connected to the molten salt steam-water heat exchanger and the high-pressure cylinder, and is used to perform a first desuperheating and pressure reduction on the received superheated steam, and then send a portion of the superheated steam after the first desuperheating and pressure reduction to the middle stage of the high-pressure cylinder; The secondary desuperheater and pressure reducer is connected to the primary desuperheater and pressure reducer and the intermediate and low pressure cylinders, and is used to perform secondary desuperheating and pressure reduction on another portion of the superheated steam after the primary desuperheating and pressure reduction, and then send the steam into the middle stage of the intermediate and low pressure cylinders.

4. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 1 is characterized in that: The steam-water circulation system further comprises: a condenser; The condenser is connected to the intermediate and low pressure cylinders and the water supply system, and is used for condensing the exhaust gas of the intermediate and low pressure cylinders into condensed water and transporting the condensed water to the water supply system through a condensate pump.

5. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 4 is characterized in that: The water supply system includes: a low-pressure heater, a deaerator and a high-pressure heater; The low-pressure heater is connected to the deaerator and is used to heat the condensate using the heat of the steam extracted from the medium and low-pressure cylinders, and to transport the obtained preheated water to the deaerator; The deaerator is connected to the high-pressure heater and is used to deoxygenate the preheated water by utilizing the heat of the steam extracted from the medium and low-pressure cylinders, and to pressurize the obtained deoxygenated water through the feed water pump and then deliver it to the high-pressure heater; The high-pressure heater is connected to the gas boiler and the molten salt steam-water heat exchanger, and is used to use the heat of the high-pressure cylinder extraction steam to further heat the pressurized deoxygenated water, and to transport the obtained high-pressure feed water to the gas boiler and the molten salt steam-water heat exchanger.

6. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 5 is characterized in that: Another portion of the superheated steam is fed into the high-pressure heater and the low-pressure heater as a steam heat source.

7. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 6 is characterized in that: Also includes: First-stage desuperheater and pressure reducer and second-stage desuperheater and pressure reducer; The first-stage desuperheater is connected to the molten salt steam-water heat exchanger and the high-pressure heater, and is used to perform a first desuperheating and pressure reduction on the received superheated steam, and then send a portion of the superheated steam after the first desuperheating and pressure reduction into the high-pressure heater; The secondary desuperheater and pressure reducer is connected to the primary desuperheater and pressure reducer and the low-pressure heater, and is used to perform secondary desuperheating and pressure reduction on another portion of the superheated steam after the primary desuperheating and pressure reduction, and then send the steam into the low-pressure heater.

8. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 1 is characterized in that: A steam bypass channel is provided between the molten salt steam-water heat exchanger and the gas boiler. A flow limiting valve is provided on the steam bypass channel. The flow limiting valve is used to limit the maximum flow of molten salt steam entering the main steam main pipe.

9. The peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to claim 8, characterized in that: The maximum flow rate does not exceed 30% of the main steam flow rate.

10. A peak-shaving power generation method coupled with molten salt heat storage and steam turbine supplementation, applied to the peak-shaving power generation system coupled with molten salt heat storage and steam turbine supplementation according to any one of claims 1 to 9, characterized in that: include: The molten salt heater receives the low-temperature molten salt fed into the low-temperature molten salt tank through the low-temperature molten salt pump during the off-peak period of electricity consumption, and heats the low-temperature molten salt with the heat provided by the gas boiler; The high-temperature molten salt tank receives and stores the heated molten salt; The molten salt steam-water heat exchanger receives the high-temperature molten salt fed into the high-temperature molten salt tank by the high-temperature molten salt pump during peak electricity consumption, and transfers the heat energy of the high-temperature molten salt to the high-pressure feed water from the water supply system to generate superheated steam; a portion of the superheated steam is fed into the main steam main pipe connected to the gas boiler; The low-temperature molten salt tank receives and stores the molten salt after heat exchange.

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