New energy large base-oriented multi-mode power generation system and operation method thereof

Abstract

The invention relates to the technical field of peak regulation of power generation systems, in particular to a multi-mode power generation system for a new energy large base and an operation method of the multi-mode power generation system. The multi-mode power generation system comprises a thermal power station and a fused salt energy storage power station. The thermal power station comprises a boiler, a first turbine, a first water return unit and a first generator; the fused salt energy storage power station comprises a high-temperature fused salt tank, a low-temperature fused salt tank, a fused salt heating unit, a steam-water heating unit, a second water return unit, a second steam turbine and a second generator; an air inlet of the fused salt heating unit is configured to obtain steam flowing out of the boiler, and a second discharging opening of the fused salt heating unit is connected with the first water return unit; an air outlet of the steam-water heating unit is connected with the first steam turbine and the second steam turbine. The first water return unit and the second water return unit are connected with a second feeding port of the steam-water heating unit. The multi-mode power generation system can set different operation modes according to different requirements, so that the new energy large base can meet higher requirements.

Description

Technical Field

[0001] This application relates to the technical field of peak shaving of power generation systems, and particularly to a multi-mode power generation system for new energy large bases and an operation method thereof. Background Art

[0002] A new energy large base refers to a large-scale energy base where multiple types of power sources such as wind power, photovoltaic power, thermal power, and energy storage facilities are synchronously constructed, synchronously grid-connected, jointly dispatched, and bundled for transmission. Large-scale construction of new energy large bases in areas such as deserts, gobi, and wastelands can not only effectively utilize local wind, light, and land resources, but also effectively cover the desert surface through the erection of photovoltaic panels, reduce groundwater evaporation, and at the same time cooperate with technologies such as under-panel planting and drip irrigation to achieve land treatment in sandy gobi areas, ultimately realizing ecological improvement while utilizing energy.

[0003] Currently, new energy large bases include new energy power stations and thermal power stations. The thermal power stations are set to operate in a flexible dispatching mode, and there is coupling between the new energy power stations and the thermal power stations. When new energy resources such as wind energy and light energy are abundant, the load of the thermal power stations is reduced; when new energy resources are insufficient, the load of the thermal power stations is increased. The thermal power stations are used to adjust the output of the new energy large bases.

[0004] With the continuous adjustment of the energy structure, higher requirements have been imposed on new energy large bases. Specifically, when new energy resources are abundant, the load of the thermal power stations needs to be further reduced; during peak electricity consumption periods, the output of the new energy large bases needs to be further increased; the rate of change of the load of the thermal power stations needs to be further increased. Therefore, it is urgent to adjust the existing power generation system to meet the above requirements. Summary of the Invention

[0005] Based on this, this application provides a multi-mode power generation system for new energy large bases and an operation method thereof to solve the deficiency that new energy large bases in the related art cannot meet higher requirements.

[0006] On the one hand, this application provides a multi-mode power generation system for new energy large bases, including a thermal power station and a molten salt energy storage power station;

[0007] The thermal power station includes a boiler, a first steam turbine, a first water return unit, and a first generator. The discharge port of the boiler is connected to the feed port of the first steam turbine. The first water return unit is connected between the first steam turbine and the boiler. The first generator is connected to the first steam turbine;

[0008] The molten salt energy storage power station includes a high-temperature molten salt tank, a low-temperature molten salt tank, a molten salt heating unit, a steam-water heating unit, a second water return unit, a second steam turbine, and a second generator. The outlet of the low-temperature molten salt tank is connected to the inlet of the molten salt heating unit, the first outlet of the molten salt heating unit is connected to the inlet of the high-temperature molten salt tank, the outlet of the high-temperature molten salt tank is connected to the first inlet of the steam-water heating unit, and the outlet of the steam-water heating unit is connected to the inlet of the low-temperature molten salt tank;

[0009] The inlet of the molten salt heating unit is configured to obtain the steam flowing out of the boiler, and the second outlet of the molten salt heating unit is connected to the first water return unit; the outlet of the steam-water heating unit is respectively connected to the first steam turbine and the second steam turbine, the outlet of the second steam turbine is connected to the second water return unit, the second generator is connected to the second steam turbine, and the first water return unit and the second water return unit are respectively connected to the second inlet of the steam-water heating unit.

[0010] In a possible implementation manner, the molten salt energy storage power station further includes an electric heater. The inlet of the electric heater is connected to the first outlet of the molten salt heating unit, the outlet of the electric heater is connected to the inlet of the high-temperature molten salt tank, and the electric heater is electrically connected to the new energy power station.

[0011] In a possible implementation manner, the outlet of the steam-water heating unit is further connected to the first water return unit.

[0012] In a possible implementation manner, the steam-water heating unit includes a plurality of sequentially connected steam heating devices, and the second water return unit includes a peak condenser, a plurality of low-pressure heaters, a deaerator, and a plurality of high-pressure heaters. The peak condenser is connected to the second steam turbine, the plurality of low-pressure heaters are sequentially connected between the peak condenser and the deaerator, and the plurality of high-pressure heaters are connected between the deaerator and the steam-water heating unit.

[0013] In a possible implementation manner, the inlets of the respective low-pressure heaters, the inlet of the deaerator, and the inlets of the respective high-pressure heaters are respectively connected in one-to-one correspondence with the outlets of the respective steam heating devices, and the drain outlets of the respective low-pressure heaters and the drain outlets of the respective high-pressure heaters are respectively connected to the peak condenser.

[0014] In a possible implementation manner, on-off valves are respectively provided on the pipelines between the respective low-pressure heaters and the corresponding steam heating devices, on the pipelines between the deaerator and the corresponding steam heating devices, and on the pipelines between the respective high-pressure heaters and the corresponding steam heating devices.

[0015] In a possible implementation manner, valves are respectively provided on the pipelines between the boiler and the first steam turbine, on the pipelines between the boiler and the molten salt heating unit, and on the pipelines between the molten salt heating unit and the first water return unit.

[0016] In a possible implementation, valves are provided on the pipelines between the steam heating unit and the first steam turbine, between the steam heating unit and the second steam turbine, between the first water return unit and the steam heating unit, and between the second water return unit and the steam heating unit.

[0017] On the other hand, the present application provides an operation method applied to the above multi-mode power generation system, which is coupled with a new energy power station. The operation method includes:

[0018] When the thermal power station is in the first state and the sum of the loads of the thermal power station and the new energy power station is greater than the power transmission load: adjust the operating load of the boiler to the lowest stable combustion load, control the steam generated by the boiler to enter the molten salt heating unit, and control the steam flowing out of the molten salt heating unit to flow back to the first water return unit;

[0019] When the thermal power station is in the first state and the sum of the loads of the thermal power station and the new energy power station is less than the power transmission load: increase the operating load of the boiler, control the steam generated by the boiler to enter the first steam turbine, control a part of the steam and water in the first water return unit to enter the steam heating unit, and control the steam flowing out of the steam heating unit to enter the first steam turbine;

[0020] When the thermal power station is in the second state and the sum of the loads of the thermal power station and the new energy power station is less than the power transmission load: control the steam generated by the boiler to enter the first steam turbine, control a part of the steam and water in the first water return unit to enter the steam heating unit, and control the steam flowing out of the steam heating unit to enter the second steam turbine;

[0021] Among them, the first state is that the boiler reaches the lowest stable combustion load, and the boiler drives the first steam turbine to drive the first generator to generate electricity; the second state is that the boiler reaches the highest load, and the boiler drives the first steam turbine to drive the first generator to generate electricity.

[0022] In a possible implementation, when the load of the new energy power station is greater than the power transmission load, control the excess power generated by the new energy power station to drive the electric heater to heat the molten salt flowing out of the molten salt heating unit.

[0023] A multi-mode power generation system for new energy large bases and its operation method provided by this application. When there is abundant new energy resources, the operation load of the boiler can be reduced to the lowest stable combustion load, and the steam generated by the boiler can flow to the molten salt heating unit to heat the molten salt. At this time, the molten salt energy storage power station is in the energy storage mode, and the load of the thermal power station can be further reduced, increasing the proportion of new energy power generation output. When there is insufficient new energy resources, part of the steam-water mixture in the first water return unit can be heated to steam via the steam-water heating unit, and the steam flowing out of the steam-water heating unit can flow to the first steam turbine together with the steam generated by the boiler, increasing the change rate of the load of the thermal power station. During peak electricity consumption periods, the steam generated by the boiler flows to the first steam turbine, and the steam generated by the steam-water heating unit flows to the second steam turbine, enabling the first generator and the second generator to generate electricity simultaneously. At this time, the power generation system is in the peak power generation mode to ensure that the output of the power generation system meets the electricity demand. In this way, the new energy large base adopting the multi-mode power generation system can meet higher requirements. Description of the Drawings

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 Schematic diagram of the power output of large base power sources in the related art;

[0026] Figure 2 Schematic diagram of the multi-mode power generation system provided by the embodiment of this application;

[0027] Figure 3 Schematic diagram of the thermal power station provided by the embodiment of this application;

[0028] Figure 4 Schematic diagram of the molten salt energy storage power station provided by the embodiment of this application;

[0029] Figure 5 Schematic diagram of the power output of large base power sources provided by the embodiment of this application;

[0030] Figure 6 Operation output diagram of the molten salt energy storage power station provided by the embodiment of this application.

[0031] Explanation of the reference numerals:

[0032] 100 - Thermal power station; 110 - Boiler; 120 - First steam turbine; 130 - First water return unit; 131 - Condenser; 132 - Low - pressure heating device; 133 - Deaerator; 134 - High - pressure heating device; 140 - First generator;

[0033] 200 - Molten salt energy storage power station; 210 - High - temperature molten salt tank; 220 - Low - temperature molten salt tank; 230 - Molten salt heating unit; 240 - Steam - water heating unit; 241 - Steam heating device; 250 - Second water return unit; 251 - Peak condenser; 252 - Low - pressure heater; 253 - Deaerator; 254 - High - pressure heater; 260 - Second steam turbine; 270 - Second generator; 280 - Electric heater;

[0034] 310 - On - off valve; 320 - Valve;

[0035] 400 - New energy power station. Detailed implementation manners

[0036] To make the objectives, technical solutions and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings in the preferred embodiments of this application. In the drawings, the same or similar reference numerals denote the same or similar components or components with the same or similar functions from beginning to end. The described embodiments are some, but not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain this application and should not be construed as a limitation of this application. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, or an indirect connection through an intermediate medium, and can be the internal connection of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the description of this application, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships in the drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0039] In the description and claims of this application and the above-mentioned drawings, the terms "first", "second", "third" (if any) are used to distinguish similar objects and do not necessarily describe a specific order or sequence.

[0040] In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or display that includes a series of steps or units need not be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or displays.

[0041] In the prior art, large new energy bases include new energy power stations and thermal power stations. The thermal power stations are set to operate in a flexible dispatching mode, and there is coupling between the new energy power stations and the thermal power stations. When new energy resources such as wind energy and solar energy are abundant, the load of the thermal power stations is reduced; when new energy resources are insufficient, the load of the thermal power stations is increased. The output of the large new energy bases is regulated by the thermal power stations. However, the load of the thermal power stations cannot achieve ultra-low load operation. The minimum stable combustion load of the boilers of the thermal power stations is generally 30% of the rated working condition. For example, for a thermal power station with a rated capacity of 1000 MW, the minimum load of the thermal power station cannot be lower than 300 MW. When the load of the boiler is lower than the minimum stable combustion load, accidents such as flameout and shutdown of the boiler are likely to occur. As Figure 1 shown, when new energy resources are abundant, the load of the thermal power stations cannot be further reduced, resulting in curtailment of new energy. The change rate of the load of the thermal power stations cannot be further adjusted, making it difficult to match the changes in new energy. The load of the boilers of the thermal power stations can be adjusted by controlling coal feeding, water feeding, air distribution, etc. However, the adjustment rate is mostly 1%-1.5% Pe / minute. That is, for a 1000 MW thermal power station, the change rate of the load of the thermal power station is about 10-15 MW / minute. If the coal feeding amount, air distribution amount and water feeding amount of the boiler are forcibly increased, malignant accidents such as local overheating of the boiler and bursting of the water wall are likely to occur. Figure 1 It is shown that during peak electricity consumption periods, the output of large new energy bases cannot meet the electricity demand, resulting in an electricity gap. Although the use of electrochemical energy storage can enable the power generation system to meet the above requirements, the cost of electrochemical energy storage is high, and the service life of electrochemical energy storage is low, and the electrochemical energy storage needs to be replaced multiple times.

[0042] After repeated thinking and verification, the inventor found that if a thermal power station is coupled with a molten salt energy storage power station, when new energy resources are abundant, the steam generated by the boiler can be transported to the molten salt energy storage power station. At this time, the molten salt energy storage power station is in the energy storage mode, reducing the steam input to the steam turbine in the thermal power station, thereby reducing the load of the thermal power station. The steam flowing out of the molten salt energy storage power station can flow to the device downstream of the steam turbine in the thermal power station. When new energy resources are insufficient, the steam generated by the boiler flows to the steam turbine of the thermal power station, and part of the steam-water mixture flowing out of the steam turbine can flow to the molten salt energy storage power station. The steam heated by the molten salt energy storage power station can flow to the steam turbine of the thermal power station, increasing the change rate of the load of the thermal power station. In addition, the molten salt energy storage power station is also equipped with a steam turbine. During peak electricity consumption periods, the steam generated by the boiler flows to the steam turbine of the thermal power station, and the steam of the molten salt energy storage power station flows to the steam turbine of the molten salt energy storage power station. The two steam turbines drive two generators to generate electricity respectively, so that the output of the power generation system meets the electricity demand. At the same time, the power generation system does not need to be equipped with electrochemical energy storage, reducing the cost of the power generation system and ensuring the service life of the power generation system.

[0043] In view of this, the inventor designed a multi-mode power generation system for large new energy bases and its operation method. The multi-mode power generation system includes a thermal power station and a molten salt energy storage power station. The thermal power station includes a boiler and a first steam turbine. The molten salt energy storage power station includes a molten salt heating unit, a steam-water heating unit, and a second steam turbine. The steam generated by the boiler can flow to the first steam turbine or the molten salt heating unit. The steam flowing out of the steam-water heating unit can flow to the first steam turbine or the second steam turbine. By adjusting the flow direction of the steam in the thermal power station and the molten salt energy storage power station, the working mode of the power generation system can be adjusted, so that the power generation system can meet more requirements.

[0044] The following will describe in detail the technical solutions of a multi-mode power generation system for large new energy bases and its operation method provided by the embodiments of the present application with reference to the accompanying drawings.

[0045] Refer to Figures 2 to 6As shown in the figure, the multi-mode power generation system for new energy large bases provided by the embodiments of the present application includes a thermal power station 100 and a molten salt energy storage power station 200. The thermal power station 100 includes a boiler 110, a first steam turbine 120, a first water return unit 130, and a first generator 140. The discharge port of the boiler 110 is connected to the feed port of the first steam turbine 120. The first water return unit 130 is connected between the first steam turbine 120 and the boiler 110. The first generator 140 is connected to the first steam turbine 120. The molten salt energy storage power station 200 includes a high-temperature molten salt tank 210, a low-temperature molten salt tank 220, a molten salt heating unit 230, a steam-water heating unit 240, a second water return unit 250, a second steam turbine 260, and a second generator 270. The discharge port of the low-temperature molten salt tank 220 is connected to the feed port of the molten salt heating unit 230. The first discharge port of the molten salt heating unit 230 is connected to the feed port of the high-temperature molten salt tank 210. The discharge port of the high-temperature molten salt tank 210 is connected to the first feed port of the steam-water heating unit 240. The discharge port of the steam-water heating unit 240 is connected to the feed port of the low-temperature molten salt tank 220. The air inlet of the molten salt heating unit 230 is configured to obtain the steam flowing out of the boiler 110. The second discharge port of the molten salt heating unit 230 is connected to the first water return unit 130. The air outlet of the steam-water heating unit 240 is respectively connected to the first steam turbine 120 and the second steam turbine 260. The discharge port of the second steam turbine 260 is connected to the second water return unit 250. The second generator 270 is connected to the second steam turbine 260. The first water return unit 130 and the second water return unit 250 are respectively connected to the second feed port of the steam-water heating unit 240.

[0046] Those skilled in the art can understand that when steam enters the first steam turbine 120, the first steam turbine 120 can drive the first generator 140 to generate electricity; when steam enters the second steam turbine 260, the second steam turbine 260 can drive the second generator 270 to generate electricity.

[0047] In a possible implementation, the boiler 110 is respectively connected to the first steam turbine 120 and the molten salt heating unit 230 through a gas supply pipeline. The gas supply pipeline includes a main pipe, a first branch pipe, and a second branch pipe. The main pipe is connected to the boiler 110. The first branch pipe is connected between the first steam turbine 120 and the main pipe. The second branch pipe is connected between the molten salt heating unit 230 and the boiler 110. The steam generated by the boiler 110 can enter the first steam turbine 120 via the main pipe and the first branch pipe, or can enter the molten salt heating unit 230 via the main pipe and the second branch pipe.

[0048] Exemplarily, such as Figure 1 and Figure 2As shown, the first water cycle unit 130 includes a condenser 131, a plurality of low-pressure heaters 132, a deaerator 133, and a plurality of high-pressure heaters 134. The condenser 131 is connected to the first steam turbine 120. The plurality of low-pressure heaters 132 can be sequentially arranged between the condenser 131 and the deaerator 133. The plurality of high-pressure heaters 134 can be sequentially arranged between the boiler 110 and the deaerator 133. The steam flowing out of the first steam turbine 120 can flow to each of the low-pressure heaters 132 and each of the high-pressure heaters 134 respectively. The condenser 131 can collect the condensate discharged from the first steam turbine 120 and each heater. Each heater can heat the water entering the boiler 110. When the steam enters the first steam turbine 120, the first steam turbine 120 can drive the first generator 140 to generate electricity.

[0049] It can be understood that the high-temperature molten salt tank 210 is used to store high-temperature molten salt, and the low-temperature molten salt tank 220 is used to store low-temperature molten salt. The molten salt in the low-temperature molten salt tank 220 can flow to the high-temperature molten salt tank 210 via the molten salt heating unit 230. When the steam enters the molten salt heating unit 230, it can heat the molten salt flowing in the molten salt heating unit 230. Exemplarily, as Figure 2 and Figure 4 shown, the molten salt heating unit 230 can include a plurality of molten salt heaters, and the plurality of molten salt heaters are sequentially connected between the high-temperature molten salt tank 210 and the low-temperature molten salt tank 220. Each molten salt heater is provided with an air inlet, a feed inlet, a first discharge outlet, and a second discharge outlet. The steam flows in from the air inlet and flows out from the second discharge outlet, and the molten salt flows in from the feed inlet and flows out from the first discharge outlet. By setting the number of molten salt heaters to be plural, the steam discharged from the boiler 110 can be used to achieve step-by-step heating of the contained molten salt, and the energy utilization rate of the power generation system can be improved. The molten salt in the high-temperature molten salt tank 210 can flow to the low-temperature molten salt tank 220 via the steam-water heating unit 240. The molten salt flowing in the steam-water heating unit 240 can heat the steam and water entering the steam-water heating unit 240, so that the steam-water heating unit 240 can discharge steam.

[0050] The multi-mode power generation system provided in this embodiment, as Figure 5 and Figure 6As shown in the figure, when there is an abundant supply of new energy resources, the operating load of the boiler 110 can be reduced to the minimum stable combustion load. The steam generated by the boiler 110 can flow to the molten salt heating unit 230 to heat the molten salt. At this time, the molten salt energy storage power station 200 is in the energy storage mode, and the load of the thermal power station can be further reduced or the thermal power output can be stopped, increasing the proportion of new energy power generation output. When there is a shortage of new energy resources, part of the steam-water mixture in the first water return unit 130 can be heated to steam via the steam-water heating unit 240. The steam flowing out of the steam-water heating unit 240 and the steam generated by the boiler 110 can jointly flow to the first steam turbine 120, increasing the rate of change of the load of the thermal power station. After the load of the thermal power station approaches saturation, it can be controlled that the steam-water mixture in the first water return unit 130 does not flow to the steam-water heating unit 240, or it can be controlled that the steam flowing out of the steam-water heating unit 240 flows to the second steam turbine 260. During the peak electricity consumption period, the steam generated by the boiler 110 flows to the first steam turbine 120, and the steam generated by the steam-water heating unit 240 flows to the second steam turbine 260, enabling the first generator 140 and the second generator 270 to generate electricity simultaneously. At this time, the power generation system is in the peak power generation mode to ensure that the power output of the power generation system meets the electricity demand. After the peak electricity consumption period, the molten salt energy storage power station 200 releases all its energy, and the second steam turbine 260 and the second generator 270 stop operating. When there is sufficient new energy resources at this time, the energy storage mode is restarted. In this way, the molten salt energy storage power station 200 is jointly dispatched and integratedly controlled with the thermal power station 100 and the new energy power station 400, and the large new energy base with a multi-mode power generation system can meet higher requirements.

[0051] With the multi-mode power generation system provided in this embodiment, the power supply can be stably delivered, the utilization rate of new energy can exceed 90%, and the proportion of new energy in the delivered electricity exceeds 50%. In addition, the multi-mode power generation system provided in this embodiment does not require the setting of electrochemical energy storage, and the power generation system has low cost, long service life, and good safety.

[0052] In one embodiment, as Figure 2 and Figure 4 shown, the molten salt energy storage power station 200 further includes an electric heater 280. The feed inlet of the electric heater 280 is connected to the first discharge outlet of the molten salt heating unit 230, the discharge outlet of the electric heater 280 is connected to the feed inlet of the high-temperature molten salt tank 210, and the electric heater 280 is electrically connected to the new energy power station 400.

[0053] Schematically, the electric heater 280 is provided with a power waste interface for electrically connecting to the new energy power station 400, where the new energy power station 400 may include a wind power station or a photovoltaic power station. It can be understood that after the molten salt flows out of the first discharge port of the molten salt heating unit 230, it can enter the electric heater 280 and flow to the high-temperature molten salt tank 210 after being heated by the electric heater 280. The molten salt energy storage power station 200 has two energy storage modes: steam heat storage and electric heat storage. Among them, the steam heating power and capacity are matched with those of the thermal power station 100, and the electric heating power and capacity are matched with the power waste situation of the large new energy base.

[0054] During the energy storage process, the steam flowing out of the boiler 110 is used to provide a medium- and low-grade heat source to heat the molten salt in the molten salt heating unit 230, and the power waste generated by the new energy power station 400 is used to provide a high-grade heat source to heat the molten salt in the electric heater 280.

[0055] In this embodiment, by setting the electric heater 280, when there is abundant new energy resources, if there is excess power in the new energy power station 400 that cannot be sent out or consumed, the excess power can drive the electric heater 280 to heat the molten salt, further storing the electric energy in the form of heat energy to achieve the consumption and storage of power waste.

[0056] In one embodiment, as Figures 2 - 4 shown, the outlet of the steam-water heating unit 240 is also connected to the first return water unit 130.

[0057] Exemplarily, a supply air pipeline is connected between the first steam turbine 120 and the high-pressure heating device 134, and the steam discharged from the first steam turbine 120 can enter the high-pressure heating device 134 via the supply air pipeline. The outlet of the steam-water heating unit 240 can be respectively connected to the first steam turbine 120, the deaerator 133, and the supply air pipeline between the first steam turbine 120 and the high-pressure heating device 134 through an outlet pipeline.

[0058] With this structure, the steam flowing out of the steam-water heating unit 240 can not only flow to the first steam turbine 120 to increase the change rate of the load of the thermal power station. At the same time, the steam flowing out of the steam-water heating unit 240 can also flow to the high-pressure heating device 134 and the deaerator 133 to provide heat sources for the high-pressure heating device 134 and the deaerator 133. In this way, the load increase rate of the boiler 110 can be improved. If all the steam flowing out of the steam-water heating unit 240 flows to the first steam turbine 120, due to the limitation of the steam quality flowing out of the steam-water heating unit 240, the effect of increasing the change rate of the load of the thermal power station is limited. For the multi-mode power generation system provided in this embodiment, both the load increase rate of the boiler 110 and the load increase rate of the first steam turbine 120 are increased, further increasing the change rate of the load of the thermal power station.

[0059] In other embodiments, the steam flowing out of the steam-water heating unit 240 may also flow to the low-pressure heating device 132, which is not uniquely defined herein.

[0060] In one embodiment, as Figure 2 and Figure 4 shown, the steam-water heating unit 240 includes a plurality of steam heating devices 241 connected in sequence. The second water return unit 250 includes a peak condenser 131, a plurality of low-pressure heaters 252, a deaerator 253, and a plurality of high-pressure heaters 254. The peak condenser 131 is connected to the second steam turbine 260. The plurality of low-pressure heaters 252 are connected in sequence between the peak condenser 131 and the deaerator 253. The plurality of high-pressure heaters 254 are connected between the deaerator 253 and the steam-water heating unit 240.

[0061] Exemplarily, the number of the steam heating devices 241 may be five. For example, in the direction from the low-temperature molten salt tank 220 to the high-temperature molten salt tank 210, the five steam heating devices 241 are respectively a preheater, a steam generator, a primary steam heater, a secondary steam heater, and a steam superheater. Each steam heating device 241 is provided with a first feed port, a second feed port, a discharge port, and a gas outlet. The molten salt flows in from the first feed port and out from the discharge port, and the steam-water flows in from the second feed port and out from the gas outlet. The steam-water flowing out of the second steam turbine 260 may flow to the boiler 110 via the peak condenser 131, the plurality of low-pressure heaters 252, the deaerator 253, and the plurality of high-pressure heaters 254 in sequence. As Figure 2 and Figure 4 shown, when the number of the steam heating devices 241 is five, the number of the low-pressure heaters 252 and the high-pressure heaters 254 may both be two. In this embodiment, the plurality of steam heating devices 241 can gradually heat the steam-water to generate steam, improving the energy utilization rate. The steam-water flowing out of the second steam turbine 260 may flow to the boiler 110 via the second water return unit 250. During this process, the second water return unit 250 can gradually heat the steam-water. The above settings can, on the one hand, realize the recycling of the steam-water and save energy; on the other hand, by heating the steam-water by the second water return unit 250, it is beneficial to increase the amount of steam discharged from the steam-water heating unit 240.

[0062] In a specific embodiment, as Figure 2 and Figure 4 shown, the air inlets of the respective low-pressure heaters 252, the air inlet of the deaerator 253, and the air inlets of the respective high-pressure heaters 254 are respectively connected in one-to-one correspondence with the gas outlets of the respective steam heating devices 241. The drain outlets of the respective low-pressure heaters 252 and the drain outlets of the respective high-pressure heaters 254 are respectively connected to the peak condenser 131.

[0063] Specifically, the steam flowing out of the preheater can enter one of the low-pressure heaters 252, the steam flowing out of the steam generator can enter another low-pressure heater 252, the steam flowing out of the primary steam heater can enter the deaerator 253, the steam flowing out of the secondary steam heater can enter one of the low-pressure heaters 252, and the steam flowing out of the steam superheater can enter another low-pressure heater 252.

[0064] Optionally, the drain outlets of the high-pressure heaters 254 and the drain outlets of the low-pressure heaters 252 can be connected to the peak condenser 131 through pipelines respectively.

[0065] In this embodiment, the steam flowing out of each steam heating device 241 can partially flow to the deaerator 253 and the heaters of the second water return unit 250. The above settings make the heating curve of the second water return unit 250 relatively gentle, reduce the exergy loss of the second water return unit 250, and improve the thermal efficiency of the molten salt energy storage power station 200.

[0066] In a more specific embodiment, as Figure 2 and Figure 4 shown, on the pipelines between each low-pressure heater 252 and the corresponding steam heating device 241, on the pipelines between the deaerator 253 and the corresponding steam heating device 241, and on the pipelines between each high-pressure heater 254 and the corresponding steam heating device 241, switching valves 310 are respectively arranged.

[0067] Specifically, on the pipelines between the preheater and one of the low-pressure heaters 252, between the steam generator and another low-pressure heater 252, between the primary steam heater and the deaerator 253, between the secondary steam heater and one of the high-pressure heaters 254, and between the steam superheater and another high-pressure heater 254, switching valves 310 are respectively arranged.

[0068] In this embodiment, by controlling the corresponding switching valves 310, the working states of the low-pressure heaters 252, the deaerator 253, and the high-pressure heaters 254 can be controlled, and the staff can control the operation of each device in the second water return unit 250 according to the temperature of the steam and water discharged by the second steam turbine 260, improving the flexibility of the molten salt energy storage power station 200.

[0069] As Figures 2 - 4 shown, on the pipelines between the boiler 110 and the first steam turbine 120, between the boiler 110 and the molten salt heating unit 230, and between the molten salt heating unit 230 and the first water return unit 130, valves 320 are respectively arranged.

[0070] Schematically, when the new energy resources are abundant, the staff can control the valve 320 on the pipeline between the boiler 110 and the first steam turbine 120 to close, open the valve 320 on the pipeline between the boiler 110 and the molten salt heating unit 230, and open the valve 320 on the pipeline between the molten salt heating unit 230 and the first water return unit 130. At this time, the steam generated by the boiler 110 enters the molten salt heating unit 230 and returns to the first water return unit 130 via the molten salt heating unit 230, which can prevent the steam from entering the first steam turbine 120 and reduce the load of the thermal power station.

[0071] When the new energy resources are insufficient, the staff can open the valve 320 on the pipeline between the boiler 110 and the first steam turbine 120, and close the valve 320 on the pipeline between the boiler 110 and the molten salt heating unit 230 and the valve 320 on the pipeline between the molten salt heating unit 230 and the first water return unit 130 respectively. At this time, the steam generated by the boiler 110 enters the first steam turbine 120 to drive the first generator 140 to generate electricity.

[0072] Through the above settings, the staff can control the working state of the multi-mode power generation system by controlling the valve 320 on the corresponding pipeline.

[0073] Continue to refer to Figures 2 - 4 , valves 320 are provided on the pipelines between the steam-water heating unit 240 and the first steam turbine 120, between the steam-water heating unit 240 and the second steam turbine 260, between the first water return unit 130 and the steam-water heating unit 240, and between the second water return unit 250 and the steam-water heating unit 240.

[0074] When the new energy resources are insufficient, the valve 320 on the pipeline between the steam-water heating unit 240 and the first steam turbine 120 can be opened, the valve 320 on the pipeline between the first water return unit 130 and the steam-water heating unit 240 can be opened, the valve 320 on the pipeline between the steam-water heating unit 240 and the second steam turbine 260 can be closed, and the valve 320 on the pipeline between the second water return unit 250 and the steam-water heating unit 240 can be closed. At this time, the steam flowing out of the steam-water heating unit 240 can enter the first steam turbine 120 to increase the ramp rate of the thermal power station 100, that is, to further increase the change rate of the load of the thermal power station.

[0075] During peak electricity consumption periods, the valves 320 on the pipeline between the steam-water heating unit 240 and the first steam turbine 120 and the valves 320 on the pipeline between the first water return unit 130 and the steam-water heating unit 240 can be closed respectively, and the valves 320 on the pipeline between the steam-water heating unit 240 and the second steam turbine 260 and the valves 320 on the pipeline between the second water return unit 250 and the steam-water heating unit 240 can be opened respectively. At this time, the steam flowing out of the steam-water heating unit 240 can enter the second steam turbine 260, and the power generation system is in the peak power generation mode.

[0076] In this embodiment, by controlling each valve 320, the movement direction of the steam flowing out of the steam-water heating unit 240 can be controlled, so that the molten salt energy storage power station 200 can increase the ramp rate of the thermal power station 100 or drive the second steam turbine 260 to make the power generation system in the peak power generation mode.

[0077] This application also provides an operation method, which is applied to the above multi-mode power generation system. The multi-mode power generation system is coupled with the new energy power station 400. The operation method includes:

[0078] When the thermal power station 100 is in the first state and the sum of the loads of the thermal power station 100 and the new energy power station 400 is greater than the power transmission load: adjust the operation load of the boiler 110 to decrease to the lowest stable combustion load, control the steam generated by the boiler 110 to enter the molten salt heating unit 230, and control the steam flowing out of the molten salt heating unit 230 to flow back to the first water return unit 130;

[0079] When the thermal power station 100 is in the first state and the sum of the loads of the thermal power station 100 and the new energy power station 400 is less than the power transmission load: increase the operation load of the boiler 110, control the steam generated by the boiler 110 to enter the first steam turbine 120, control a part of the steam and water in the first water return unit 130 to enter the steam-water heating unit 240, and control the steam flowing out of the steam-water heating unit 240 to enter the first steam turbine 120;

[0080] When the thermal power station 100 is in the second state and the sum of the loads of the thermal power station 100 and the new energy power station 400 is less than the power transmission load: control the steam generated by the boiler 110 to enter the first steam turbine 120, control a part of the steam and water in the first water return unit 130 to enter the steam-water heating unit 240, and control the steam flowing out of the steam-water heating unit 240 to enter the second steam turbine 260;

[0081] Among them, the first state is that the boiler 110 reaches the lowest stable combustion load, and the boiler 110 drives the first steam turbine 120 to drive the first generator 140 to generate electricity; the second state is that the boiler 110 reaches the highest load, and the boiler 110 drives the first steam turbine 120 to drive the first generator 140 to generate electricity.

[0082] Exemplarily, when the thermal power plant 100 is in the first state and the sum of the loads of the thermal power plant 100 and the new energy power plant 400 is greater than the power transmission load, it indicates that the new energy resources are abundant. At this time, the load of the boiler 110 can be adjusted to 30% of the rated load, that is, the minimum stable combustion load. When the steam generated by the boiler 110 enters the molten salt heating unit 230, the first steam turbine 120 stops admitting steam, and the thermal power plant 100 stops operating.

[0083] When the thermal power plant 100 is in the first state and the sum of the loads of the thermal power plant 100 and the new energy power plant 400 is less than the power transmission load, it indicates that the new energy resources are insufficient. The load of the boiler 110 can be gradually increased to 100% of the rated load. The steam flowing out of the steam-water heating unit 240 enters the first steam turbine 120, which improves the ramp rate of the thermal power plant 100. Optionally, the steam flowing out of the steam-water heating unit 240 can also enter the first water return unit 130, which improves the load increase rate of the boiler 110. After the ramp rate of the power generation system is improved, there is no need to set up electrochemical energy storage in the power generation system, which reduces the cost of the power generation system, and the power generation system has a long service life and good safety.

[0084] During the peak electricity consumption period, the first steam turbine 120 and the second steam turbine 260 work simultaneously to meet the electricity demand, and there is no need to set up electrochemical energy storage in the power generation system, saving the cost of electrochemical energy storage.

[0085] For the operation method provided in this embodiment, the power generation system can adjust the working mode according to different requirements, and the power generation system can meet the requirements of a new energy utilization rate exceeding 90%, a new energy proportion exceeding 50%, and stable power supply.

[0086] In a possible implementation manner, when the load of the new energy power plant 400 is greater than the power transmission load, it is controlled that the excess power generated by the new energy power plant 400 drives the electric heater 280 to heat the molten salt flowing out of the molten salt heating unit 230.

[0087] Among them, when the load of the new energy power plant 400 is greater than the power transmission load, it indicates that the new energy resources are excessive. The molten salt energy storage power plant 200 has two ways of heating molten salt, namely steam heating and electric heating. By setting the electric heater 280, the abandoned electricity can be directly consumed and stored when the new energy resources are excessive.

[0088] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A multi-mode power generation system for large-scale new energy bases, characterized in that, It includes a thermal power station and a molten salt energy storage power station; The thermal power station includes a boiler, a first steam turbine, a first water return unit and a first generator. The discharge port of the boiler is connected to the feed port of the first steam turbine. The first water return unit is connected between the first steam turbine and the boiler. The first generator is connected to the first steam turbine; The molten salt energy storage power station includes a high-temperature molten salt tank, a low-temperature molten salt tank, a molten salt heating unit, a steam-water heating unit, a second water return unit, a second steam turbine and a second generator. The discharge port of the low-temperature molten salt tank is connected to the feed port of the molten salt heating unit. The first discharge port of the molten salt heating unit is connected to the feed port of the high-temperature molten salt tank. The discharge port of the high-temperature molten salt tank is connected to the first feed port of the steam-water heating unit. The discharge port of the steam-water heating unit is connected to the feed port of the low-temperature molten salt tank; The air inlet of the molten salt heating unit is configured to obtain the steam flowing out of the boiler. The second discharge port of the molten salt heating unit is connected to the first water return unit. The air outlet of the steam-water heating unit is respectively connected to the first steam turbine and the second steam turbine. The discharge port of the second steam turbine is connected to the second water return unit. The second generator is connected to the second steam turbine. The first water return unit and the second water return unit are respectively connected to the second feed port of the steam-water heating unit.

2. The multimode power generation system according to claim 1, wherein The molten salt energy storage power station further includes an electric heater. The feed port of the electric heater is connected to the first discharge port of the molten salt heating unit. The discharge port of the electric heater is connected to the feed port of the high-temperature molten salt tank. The electric heater is electrically connected to a new energy power station.

3. The multimode power generation system according to claim 1, wherein The air outlet of the steam-water heating unit is also connected to the first water return unit.

4. The multimode power generation system according to claim 1, wherein The steam-water heating unit includes a plurality of steam heating devices connected in sequence. The second water return unit includes a peak condenser, a plurality of low-pressure heaters, a deaerator and a plurality of high-pressure heaters. The peak condenser is connected to the second steam turbine. The plurality of low-pressure heaters are sequentially connected between the peak condenser and the deaerator. The plurality of high-pressure heaters are connected between the deaerator and the steam-water heating unit.

5. The multimode power generation system according to claim 4, characterized in that The air inlets of each of the low-pressure heaters, the air inlet of the deaerator and the air inlets of each of the high-pressure heaters are respectively connected in one-to-one correspondence with the air outlets of each of the steam heating devices. The drain ports of each of the low-pressure heaters and the drain ports of each of the high-pressure heaters are respectively connected to the peak condenser.

6. The multi-mode power generation system according to claim 5, wherein, Switch valves are respectively provided on the pipelines between each of the low-pressure heaters and the corresponding steam heating devices, the pipelines between the deaerator and the corresponding steam heating devices, and the pipelines between each of the high-pressure heaters and the corresponding steam heating devices.

7. The multimode power generation system according to any one of claims 1-6, characterized in that, Valves are respectively provided on the pipelines between the boiler and the first steam turbine, the pipelines between the boiler and the molten salt heating unit, and the pipelines between the molten salt heating unit and the first water return unit.

8. The multimode power generation system according to claim 7, wherein Valves are provided on the pipelines between the steam heating unit and the first steam turbine, between the steam heating unit and the second steam turbine, between the first water return unit and the steam heating unit, and between the second water return unit and the steam heating unit.

9. A running method, characterized in that, Applied to the multi-mode power generation system according to any one of claims 1-8, the multi-mode power generation system is coupled with a new energy power station, and the operation method includes: When the thermal power station is in the first state and the sum of the loads of the thermal power station and the new energy power station is greater than the power transmission load: adjust the operation load of the boiler to be reduced to the lowest stable combustion load, control the steam generated by the boiler to enter the molten salt heating unit, and control the steam flowing out of the molten salt heating unit to flow back to the first water return unit; When the thermal power station is in the first state and the sum of the loads of the thermal power station and the new energy power station is less than the power transmission load: increase the operation load of the boiler, control the steam generated by the boiler to enter the first steam turbine, control a part of the steam and water in the first water return unit to enter the steam heating unit, and control the steam flowing out of the steam heating unit to enter the first steam turbine; When the thermal power station is in the second state and the sum of the loads of the thermal power station and the new energy power station is less than the power transmission load: control the steam generated by the boiler to enter the first steam turbine, control a part of the steam and water in the first water return unit to enter the steam heating unit, and control the steam flowing out of the steam heating unit to enter the second steam turbine; Wherein, the first state is that the boiler reaches the lowest stable combustion load, and the boiler drives the first steam turbine to drive the first generator to generate electricity; the second state is that the boiler reaches the highest load, and the boiler drives the first steam turbine to drive the first generator to generate electricity.

10. The operating method according to claim 9, characterized in that, When the load of the new energy power station is greater than the power transmission load, control the excess power generated by the new energy power station to drive the electric heater to heat the molten salt flowing out of the molten salt heating unit.

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