Turbine with less steam and reactive power working condition cooling steam system coupled with molten salt carnot cell

Abstract

The embodiment of the present disclosure provides a steam turbine low-steam non-reactive working condition cooling steam system coupled with a molten salt Carnot battery, which comprises: a molten salt energy storage unit, a high-temperature molten salt outlet of the molten salt energy storage unit being communicated with a molten salt side inlet of a steam generating device, and a low-temperature molten salt inlet of the molten salt energy storage unit being communicated with a molten salt side outlet of the steam generating device; a steam generating unit, comprising the steam generating device and a feedwater pipeline communicated with the steam generating device, and a steam distribution pipeline connected to a steam outlet of the steam generating device; a steam turbine through-flow unit, a high-temperature steam inlet of a high-pressure cylinder of the steam turbine through-flow unit being communicated with the steam distribution pipeline through a main steam pipeline; a cooling steam header, an inlet of the cooling steam header being communicated with the steam distribution pipeline through a branch pipeline, and an outlet of the cooling steam header being connected to a cooling steam inlet of a cylinder of the steam turbine through-flow unit through a cooling steam pipeline; and further comprising: an attemperator arranged in the branch pipeline, and a flow regulating valve arranged in the cooling steam pipeline.

Description

Technical Field

[0001] The embodiments disclosed herein belong to the field of energy and power technology, specifically relating to a steam cooling system for a steam turbine under low steam reactive power conditions coupled with a molten salt Carnot battery. Background Technology

[0002] Molten salt Carnot battery systems are large-scale, long-term energy storage technologies based on molten salt thermal energy storage. They achieve energy storage and release through an "electricity-heat-electricity" conversion process. During charging, surplus electrical energy is used to heat the molten salt to store thermal energy; during discharging, the high-temperature molten salt heats water to generate steam, which drives a turbine to generate electricity. They are primarily used for grid peak shaving, renewable energy consumption, and industrial waste heat utilization.

[0003] In the non-heat-releasing power-generating phase of a molten salt Carnot battery system, the steam flow is too small to drive the turbine. To prevent damage to components due to thermal stress caused by frequent start-stop cycles, the turbine needs to be in a hot standby state. In this state, the turbine operates in a "low-steam, no-power" condition, meaning no or very little steam enters the turbine to perform work. The turbine is driven by a generator-motor system. The turbine blades and cylinder will still continuously heat up due to blade blowout cooling. Therefore, a small amount of cooling steam must be introduced into the turbine cylinder to prevent overheating. Traditionally, cooling steam comes from boilers or adjacent units, resulting in energy waste, strong system dependence, and slow response.

[0004] Therefore, how to solve the above problems has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The embodiments disclosed herein aim to at least solve one of the technical problems existing in the prior art, and provide a steam cooling system for turbines operating under low steam reactive power conditions coupled with molten salt Carnot batteries.

[0006] One aspect of the embodiments of this disclosure provides a steam cooling system for a steam turbine operating under low-steam, reactive power conditions coupled with a molten salt Carnot battery, comprising: The high-temperature molten salt outlet of the molten salt energy storage unit is connected to the molten salt side inlet of the steam generator, and the low-temperature molten salt inlet of the molten salt energy storage unit is connected to the molten salt side outlet of the steam generator. A steam generating unit includes the steam generating device and a water supply pipeline connected to the steam generating device, and the steam outlet of the steam generating device is connected to a steam distribution pipeline; The high-temperature steam inlet of the high-pressure cylinder of the steam turbine flow unit is connected to the steam distribution pipeline through the main steam pipeline; The cooling steam header has its inlet connected to the steam distribution pipeline via a branch pipeline, and its outlet connected to the cooling steam inlet of the pressure cylinder of the turbine flow unit via a cooling steam pipeline; it also includes: A desuperheater and pressure reducer installed in the branch pipeline, and a flow regulating valve installed in the cooling steam pipeline; The steam distribution pipeline is equipped with a first control valve group for controlling the steam flow to the main steam pipeline, and the branch pipeline is equipped with a second control valve group for controlling the steam flow to the cooling steam header.

[0007] Optionally, the molten salt energy storage unit includes a cryogenic molten salt tank, a cryogenic molten salt pump, a molten salt electric heater, and a high-temperature molten salt tank connected sequentially by pipelines. The high-temperature molten salt outlet of the high-temperature molten salt tank is connected to the molten salt side inlet of the steam generator, and the cryogenic molten salt inlet of the cryogenic molten salt tank is connected to the molten salt side outlet of the steam generator.

[0008] Optionally, the turbine flow path unit includes a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder connected sequentially through the main steam pipeline.

[0009] Optionally, the flow regulating valve includes a first flow regulating valve disposed on a cooling steam pipeline connected to the high-pressure cylinder, a second flow regulating valve disposed on a cooling steam pipeline connected to the intermediate-pressure cylinder, and a third flow regulating valve disposed on a cooling steam pipeline connected to the low-pressure cylinder.

[0010] Optionally, the molten salt energy storage unit further includes a molten salt electric heater disposed in the pipeline between the high-temperature molten salt tank and the low-temperature molten salt tank, and a power supply electrically connected to the molten salt electric heater.

[0011] Optionally, a condenser connected to the exhaust port of the low-pressure cylinder may also be included.

[0012] Optionally, it may also include a generator that is drivenly connected to the turbine flow passage unit, wherein the generator is configured to drive the turbine flow passage unit to rotate in electric motor mode.

[0013] Optionally, the steam generating device includes a molten salt-water heat exchanger or a molten salt-steam heat exchanger.

[0014] The beneficial effects of the embodiments of this disclosure include: This application deeply couples the thermal energy storage of a molten salt Carnot battery system with the cooling requirements of a steam turbine under specific operating conditions. The molten salt energy storage unit serves as an independent and controllable heat source, driving the steam generation unit to produce steam. Through coordinated control of the valve group and the cooling steam header, when the steam turbine is in a "low steam, no power" hot standby state, the steam can be directionally and adjustably introduced into each cylinder of the turbine's flow path unit for cooling. This system achieves self-sufficiency in cooling steam, fundamentally solving the problems of energy waste, slow response, and high system dependence caused by traditional solutions relying on external boilers, thus improving the overall operational economy, flexibility, and safety. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of a turbine cooling steam system under low-steam, reactive power conditions coupled with a molten salt Carnot battery, according to an embodiment of this disclosure.

[0016] In the diagram, 1. High-temperature molten salt tank; 2. High-temperature molten salt pump; 3. Steam generator; 4. Low-temperature molten salt tank; 5. Low-temperature molten salt pump; 6. Molten salt electric heater; 7. Power supply; 8. High-pressure cylinder; 9. Medium-pressure cylinder; 10. Low-pressure cylinder; 11. Condenser; 12. Desuperheater and pressure reducer; 13. Cooling steam header; 14. Generator; 15. First flow regulating valve; 16. Second flow regulating valve; 17. Third flow regulating valve. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of this disclosure, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] The embodiments of this application will be further described in detail below with reference to the accompanying drawings and examples. The detailed descriptions and accompanying drawings of the following embodiments are used to exemplarily illustrate the principles of this application, but should not be used to limit the scope of this application; that is, this application is not limited to the described embodiments. In the description of this application, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicating orientation or positional relationships 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, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. "Vertical" is not strictly vertical, but within the allowable error range. "Parallel" is not strictly parallel, but within the allowable error range.

[0019] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0020] like Figure 1 As shown, a cooling steam system for a steam turbine under low-steam, reactive power conditions coupled with a molten salt Carnot battery includes a molten salt energy storage unit, a steam generation unit, a steam turbine flow passage unit, and a cooling steam header 13.

[0021] The high-temperature molten salt outlet of the molten salt energy storage unit is connected to the molten salt side inlet of the steam generator 3, and the low-temperature molten salt inlet of the molten salt energy storage unit is connected to the molten salt side outlet of the steam generator 3.

[0022] The steam generating unit includes the steam generating device 3 and a water supply pipeline connected to the steam generating device 3. The steam outlet of the steam generating device 3 is connected to a steam distribution pipeline 20.

[0023] The high-temperature steam inlet of the high-pressure cylinder 8 of the steam turbine flow unit is connected to the steam distribution pipeline 20 through the main steam pipeline 21.

[0024] The inlet of the cooling steam header 13 is connected to the steam distribution pipeline 20 via a branch pipeline 22, and the outlet of the cooling steam header 13 is connected to the cooling steam inlet of the pressure cylinder of the turbine flow unit via a cooling steam pipeline 23. Specifically, the outlet of the cooling steam header 13 is connected to the cooling steam inlets of the high-pressure cylinder 8, the intermediate-pressure cylinder 9, and the low-pressure cylinder 10 via the cooling steam pipeline 23.

[0025] The system also includes a desuperheater and pressure reducer 12 installed in the branch pipeline 22, and a flow regulating valve installed in the cooling steam pipeline 23.

[0026] The steam distribution pipeline is equipped with a first control valve group for controlling the steam flow to the main steam pipeline 21, and the branch pipeline 22 is equipped with a second control valve group for controlling the steam flow to the cooling steam header 13.

[0027] Furthermore, under the condition of low steam power consumption, the first control valve group on the main steam pipeline leading to the turbine flow unit to perform work is closed or reduced, and the second control valve group on the branch pipeline of the cooling steam header 13 is opened, so that the steam generated by the steam generator is directly introduced into each cylinder in the turbine flow unit for cooling.

[0028] This application deeply couples the thermal energy storage of the molten salt Carnot battery system with the cooling requirements of the steam turbine under special operating conditions. The molten salt energy storage unit serves as an independent and controllable heat source, driving the steam generation unit to produce steam. Through the coordinated control of the valve group and the cooling steam header 13, when the steam turbine is in a "low steam, no power" hot standby state, the steam can be directionally and adjustablely introduced into each cylinder of the turbine's flow path unit for cooling. This system achieves self-sufficiency in cooling steam, fundamentally solving the problems of energy waste, slow response, and strong system dependence caused by the reliance on external boilers in traditional solutions, thus improving the overall operational economy, flexibility, and safety.

[0029] In some embodiments, the molten salt energy storage unit includes a cryogenic molten salt tank 4, a cryogenic molten salt pump 5, a molten salt electric heater 6, and a high-temperature molten salt tank 1 connected in sequence by pipelines. The high-temperature molten salt outlet of the high-temperature molten salt tank 1 is connected to the molten salt side inlet of the steam generator 3, and the cryogenic molten salt inlet of the cryogenic molten salt tank 4 is connected to the molten salt side outlet of the steam generator 3.

[0030] In this application, the above-mentioned configuration can ensure the reliability and operational efficiency of the thermal energy storage, boosting and release cycle.

[0031] In some embodiments, the turbine flow path unit includes a high-pressure cylinder 8, an intermediate-pressure cylinder 9, and a low-pressure cylinder 10 connected sequentially through the main steam pipeline.

[0032] In some embodiments, the flow regulating valve includes a first flow regulating valve 15 disposed on a cooling steam pipeline connected to the high-pressure cylinder 8, a second flow regulating valve 16 disposed on a cooling steam pipeline connected to the intermediate-pressure cylinder 9, and a third flow regulating valve 17 disposed on a cooling steam pipeline connected to the low-pressure cylinder 10.

[0033] In this application, by setting independent flow regulating valves for the cooling steam pipelines of the high, medium and low pressure cylinders 10, the cooling steam flow of each cylinder is precisely and independently controlled. This allows the cooling steam to be allocated according to the actual heat dissipation needs of each cylinder, optimizing the cooling effect and improving the safety and controllability of the system operation.

[0034] In some embodiments, the molten salt energy storage unit further includes a molten salt electric heater 6 disposed in a pipeline between the high-temperature molten salt tank 1 and the low-temperature molten salt tank 4, and a power supply 7 electrically connected to the molten salt electric heater 6.

[0035] In some embodiments, a condenser 11 is also included, which is connected to the exhaust port of the low-pressure cylinder 10.

[0036] In some embodiments, a generator 14 is also included, which is drivenly connected to the turbine flow passage unit, wherein the generator 14 is configured to drive the turbine flow passage unit to rotate in electric motor mode.

[0037] In this application, by configuring the generator 14 to drive the turbine in electric motor mode, the system can actively maintain the turbine speed under the "low steam and no power" condition, achieve stable hot standby, create conditions for rapid switching back to the power generation mode, and enhance the stability and responsiveness of the system operation.

[0038] In some embodiments, the steam generating device 3 includes a molten salt-water heat exchanger or a molten salt-steam heat exchanger.

[0039] Specifically, this application provides a steam cooling system for a steam turbine under low steam and reactive power conditions coupled with a molten salt Carnot battery. By storing and releasing the thermal energy of the molten salt Carnot battery, it provides stable and controllable cooling steam for the steam turbine under low steam and reactive power conditions, solving the defects of insufficient cooling and reliance on boilers in traditional systems.

[0040] The system includes a molten salt energy storage unit, a steam generation unit, a steam turbine flow passage unit, and a cooling steam header 13.

[0041] The molten salt energy storage unit includes a cryogenic molten salt tank 4, a high-temperature molten salt tank 1, a cryogenic molten salt pump 5, a high-temperature molten salt pump 2, and a molten salt electric heater 6. The outlet of the cryogenic molten salt tank 4 is connected to the molten salt electric heater 6 via the cryogenic molten salt pump 5, and after heating, the molten salt is sent to the high-temperature molten salt tank 1 for storage. The outlet of the high-temperature molten salt tank 1 is connected to the molten salt side inlet of the steam generator via the high-temperature molten salt pump 2, and after releasing heat, it returns to the cryogenic molten salt tank 4, forming a molten salt cycle.

[0042] The steam generator in the steam generation unit is fed with feedwater on the water side, absorbs heat from the molten salt to generate steam, and has two outlets: One path, after being regulated by the desuperheater and pressure reducer 12, is connected to the cooling steam header 13 for supplying cooling steam to the turbine under conditions of low steam power consumption. The other path sequentially feeds steam into the turbine's high-pressure cylinder 8, intermediate-pressure cylinder 9, and low-pressure cylinder 10 to perform work, and the exhaust steam enters the condenser 11.

[0043] Furthermore, the cooling steam header 13 is connected to the cooling steam inlets of each cylinder of the turbine (high-pressure cylinder 8, intermediate-pressure cylinder 9, and low-pressure cylinder 10), and the flow regulating valve includes a first flow regulating valve 15 installed on the cooling steam pipeline connected to the high-pressure cylinder 8, a second flow regulating valve 16 installed on the cooling steam pipeline connected to the intermediate-pressure cylinder 9, and a third flow regulating valve 17 installed on the cooling steam pipeline connected to the low-pressure cylinder 10, and safety valves are correspondingly installed on the cooling steam pipelines corresponding to the high-pressure cylinder 8, intermediate-pressure cylinder 9, and low-pressure cylinder 10.

[0044] In the case of low steam power consumption, the first control valve group on the main steam pipeline leading to the turbine to perform work is closed or reduced, and the second control valve group on the branch pipeline of the cooling steam header 13 is opened to directly introduce the steam generated by the steam generator into each cylinder for cooling.

[0045] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A steam cooling system for a steam turbine operating under low-steam, reactive power conditions coupled with a molten salt Carnot battery, characterized in that, include: The high-temperature molten salt outlet of the molten salt energy storage unit is connected to the molten salt side inlet of the steam generator, and the low-temperature molten salt inlet of the molten salt energy storage unit is connected to the molten salt side outlet of the steam generator. A steam generating unit includes the steam generating device and a water supply pipeline connected to the steam generating device, and the steam outlet of the steam generating device is connected to a steam distribution pipeline; The high-temperature steam inlet of the high-pressure cylinder of the steam turbine flow unit is connected to the steam distribution pipeline through the main steam pipeline; The cooling steam header has its inlet connected to the steam distribution pipeline via a branch pipeline, and its outlet connected to the cooling steam inlet of the pressure cylinder of the turbine flow unit via a cooling steam pipeline; it also includes: A desuperheater and pressure reducer installed in the branch pipeline, and a flow regulating valve installed in the cooling steam pipeline; The steam distribution pipeline is equipped with a first control valve group for controlling the steam flow to the main steam pipeline, and the branch pipeline is equipped with a second control valve group for controlling the steam flow to the cooling steam header.

2. The system according to claim 1, characterized in that, The molten salt energy storage unit includes a low-temperature molten salt tank, a low-temperature molten salt pump, a molten salt electric heater, and a high-temperature molten salt tank connected in sequence by pipelines. The high-temperature molten salt outlet of the high-temperature molten salt tank is connected to the molten salt side inlet of the steam generator, and the low-temperature molten salt inlet of the low-temperature molten salt tank is connected to the molten salt side outlet of the steam generator.

3. The system according to claim 1, characterized in that, The turbine flow path unit includes a high-pressure cylinder, an intermediate-pressure cylinder, and a low-pressure cylinder connected sequentially through the main steam pipeline.

4. The system according to claim 3, characterized in that, The flow regulating valve includes a first flow regulating valve disposed on a cooling steam pipeline connected to the high-pressure cylinder, a second flow regulating valve disposed on a cooling steam pipeline connected to the intermediate-pressure cylinder, and a third flow regulating valve disposed on a cooling steam pipeline connected to the low-pressure cylinder.

5. The system according to claim 2, characterized in that, The molten salt energy storage unit also includes a molten salt electric heater installed in the pipeline between the high-temperature molten salt tank and the low-temperature molten salt tank, and a power supply electrically connected to the molten salt electric heater.

6. The system according to claim 3, characterized in that, It also includes a condenser connected to the exhaust port of the low-pressure cylinder.

7. The system according to claim 1, characterized in that, It also includes a generator that is drivenly connected to the turbine flow passage unit, wherein the generator is configured to drive the turbine flow passage unit to rotate in electric motor mode.

8. The system according to claim 1, characterized in that, The steam generating device includes a molten salt-water heat exchanger or a molten salt-steam heat exchanger.

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