Steel heat storage and power generation coupling system

Abstract

This utility model discloses a steel thermal energy storage and power generation coupling system, including a thermal energy storage passage surrounding a solid thermal energy storage device and a heat release passage composed of the solid thermal energy storage device and a heat exchanger. The heat release passage is as follows: the heat medium inlet of the heat exchanger is connected to the high-temperature medium outlet of the solid thermal energy storage device, and the cold medium outlet of the heat exchanger is connected to the steam inlet of the power generation system. The heat exchanger is used to receive the thermal energy stored in the solid thermal energy storage device when the power generation system does not need to reduce its load, and generate steam by exchanging heat with the feed water from the power generation system. The steam is then transported to the power generation system for power generation. This utility model solves the problems of high energy storage cost, short service life, and high safety risk in electrochemical energy storage, as well as the problems of high molten salt solidification risk, high power consumption, and high cost of molten salt-related equipment and materials in molten salt energy storage.

Description

Technical Field

[0001] This utility model belongs to the field of thermal energy storage and power generation coupling, and relates to a steel thermal energy storage and power generation coupling system. Background Technology

[0002] The limited operational flexibility of thermal power generating units is mainly due to constraints imposed by factors such as their role in external heat supply and the design of boilers for stable combustion loads, resulting in relatively low safe operation. With the large-scale integration of renewable energy sources such as photovoltaics and wind power, thermal power generating units need to undertake more peak-shaving tasks, smoothing out the fluctuations in renewable energy generation. This requires reducing load during periods of high renewable energy generation to free up capacity, and increasing load during periods of low renewable energy generation to ensure power supply. Therefore, it is necessary to expand the operating load range of existing thermal power generating units.

[0003] Equipping generator sets with energy storage can significantly improve the flexibility of unit operation. Currently, the most commonly used types include electrochemical energy storage and molten salt energy storage. Among them, electrochemical energy storage uses batteries to store and release electrical energy, which has the advantages of high electricity-to-electricity conversion efficiency, simple system operation, and fast implementation cycle. However, it also has the disadvantages of high energy storage cost, short service life, and high safety risks. Molten salt energy storage, as a form of thermal energy storage, has the advantages of mature technology, high heat storage temperature, and high compatibility with the original system. However, it also has the disadvantages of high risk of molten salt solidification, high power consumption, and high cost of molten salt-related equipment and materials.

[0004] Therefore, it is urgent to solve the problems of high energy storage cost, short service life and high safety risk of electrochemical energy storage, as well as the high risk of molten salt solidification, high power consumption and high cost of molten salt related equipment and materials of molten salt energy storage, and to find an energy storage form with simple structure and high heat storage capacity to couple with generator sets in order to significantly improve the operating load range of the generator sets. Utility Model Content

[0005] To achieve the above objectives, this utility model provides a steel thermal storage and power generation coupling system, which solves the problems of high energy storage cost, short service life, and high safety risk of electrochemical energy storage, as well as the problems of high molten salt solidification risk, high power consumption, and high cost of molten salt-related equipment and materials in molten salt energy storage.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is a steel thermal storage and power generation coupling system, including a thermal storage passage arranged around a solid thermal storage device and a heat release passage composed of a solid thermal storage device and a heat exchanger; the input terminal of the electric heating element of the solid thermal storage device is connected to the output terminal of the generator of the power generation system through a cable.

[0007] The heat storage pathway is as follows: the high-temperature medium inlet and high-temperature medium outlet of the solid-state heat storage device are connected by a connecting pipeline. A heat circulation fan is installed on the connecting pipeline. The solid-state heat storage device is used to receive electrical energy from the power generation system when the power generation system needs to reduce its load, and then convert the electrical energy into heat energy.

[0008] The heat release pathway is as follows: the heat medium inlet of the heat exchanger is connected to the high-temperature medium outlet of the solid-state thermal storage device, and the cold medium outlet of the heat exchanger is connected to the steam inlet of the power generation system. The heat exchanger is used to receive the heat energy stored in the solid-state thermal storage device when the power generation system does not need to reduce the load, and generate steam by exchanging heat with the feed water from the power generation system, and then transport the steam to the power generation system for power generation.

[0009] The beneficial effects of this utility model are:

[0010] This invention relates to a steel heat storage and release subsystem coupled to a thermal power generating unit. When the thermal power generating unit needs to reduce its load for peak shaving, a portion of the generated electricity can be drawn out to heat the steel, storing some of the heat in the high-temperature steel. This allows the load reduction of the unit to be unaffected by the boiler's minimum stable combustion load, increasing the peak shaving range of the thermal power generating unit and significantly improving its operational flexibility. When the thermal power generating unit does not need to reduce its load for peak shaving, the heat from the high-temperature steel can be used to heat the feedwater or heating return water to generate steam, which can be used for external heating or fed into the turbine and generator for power generation. This reduces the fuel consumption of the thermal power generating unit, improves its energy utilization efficiency, and increases its economic efficiency.

[0011] The steel heat storage and release subsystem of this utility model has a simple structure, low operating cost, long service life, and low safety risk. In addition, steel can store heat at a high temperature. Using steel as the heat storage medium can generate high-temperature and high-pressure steam exceeding 600°C, which can be applied to large-capacity and high-parameter generator sets. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model.

[0013] Figure 2 This is a schematic diagram of the solid-state thermal storage device of this utility model.

[0014] In the diagram, 1. Power generation system, 2. Steel heat storage and release subsystem, 11. Boiler, 12. High-pressure cylinder of steam turbine, 13. Medium and low-pressure cylinder of steam turbine, 14. Generator, 15. Low-pressure heater, 16. Deaerator, 17. High-pressure heater, 18. Power grid, 21. Solid-state heat storage device, 22. Heat exchanger, 23. Circulating fan, 24. Heating return water pipeline, 25. External heating pipeline, 31. First valve, 32. Second valve, 33. Third valve, 34. Fourth valve, 35. Fifth valve, 201. Steel structure frame, 202. Refractory material, 203. Steel bar, 204. Electric heating element, 205. Flow channel space, 206. Concrete foundation. Detailed Implementation

[0015] This utility model discloses a steel thermal storage and power generation coupling system, such as Figure 1 As shown, it includes a heat storage passage surrounding the solid-state heat storage device (21) and a heat release passage consisting of the solid-state heat storage device (21) and a heat exchanger (22); the input terminal of the electric heating element (204) of the solid-state heat storage device (21) is connected to the output terminal of the generator (14) of the power generation system (1) via a cable.

[0016] The heat storage path is as follows: the high-temperature medium inlet and high-temperature medium outlet of the solid heat storage device 21 are connected by a connecting pipe. A heat circulation fan 23 is installed on the connecting pipe. The solid heat storage device 21 is used to receive the electrical energy of the power generation system 1 when the power generation system 1 needs to reduce the load, and then convert the electrical energy into heat energy.

[0017] The heat release pathway is as follows: the heat medium inlet of the heat exchanger 22 is connected to the high temperature medium outlet of the solid heat storage device 21, and the cold medium outlet of the heat exchanger 22 is connected to the steam inlet of the power generation system 1. The heat exchanger 22 is used to receive the heat energy stored in the solid heat storage device 21 when the power generation system 1 does not need to reduce the load, and generate steam by exchanging heat with the feed water from the power generation system 1, and then transport the steam to the power generation system 1 for power generation.

[0018] When the power generation system 1 needs to reduce its load, the solid-state thermal storage device 21 is electrically connected to the power generation system 1. The solid-state thermal storage device 21 is used to receive part of the electrical energy of the power generation system 1 and then convert the electrical energy into heat energy.

[0019] When the power generation system 1 does not require load reduction, the heat exchanger 22 is used to receive the heat energy stored in the solid-state thermal storage device 21, and generate steam by exchanging heat with the feed water from the power generation system 1, and then transport the steam to the power generation system 1 to generate electricity.

[0020] Preferably, the cold medium outlet of heat exchanger 22 is also connected to an external heat-demanding terminal via a pipeline. Similarly, the cold medium inlet of heat exchanger 22 is connected to the return water of the external heat-demanding terminal via a pipeline. Heat exchanger 22 enables heat exchange between the heat medium and steam, as well as between the heat medium and water, and can be configured as a single unit or multiple units connected in series or parallel.

[0021] Preferably, the cold medium inlet of the heat exchanger 22 is also connected to the return water pipeline of the power generation system 1 through a pipeline; that is, the cold medium inlet of the heat exchanger 22 is connected to the outlet of the high-pressure heater 17 in the power generation system 1; then, when the power generation system 1 does not need to reduce the load, the hot medium inlet of the heat exchanger 22 is connected to the high-temperature medium outlet of the solid heat storage device 21, and the hot medium outlet of the heat exchanger 22 is connected to the high-temperature medium inlet of the solid heat storage device 21, thereby forming a circulation.

[0022] In addition to the electric heating element 204, the solid-state thermal storage device 21 also includes: a steel structure frame 201 and steel bars 203.

[0023] The steel frame 201 has a high-temperature medium inlet and a high-temperature medium outlet; the outside of the steel frame 201 is provided with refractory material 202.

[0024] The steel rod 203 is located inside the steel structure frame 201 and is used to store thermal energy.

[0025] The electric heating element 204 is located in the inner cavity of the steel structure frame 201, and the electric heating element 204 and the steel rod 203 are arranged alternately. The electric heating element 204 is used to convert electrical energy into heat energy.

[0026] A flow channel space 205 is provided between the steel rod 203, the electric heating element 204, and the steel structure frame 201. The flow channel space 205 is used to accommodate the flow of the heat medium. The steel structure frame 201, the steel rod 203, and the electric heating element 204 are all fixed above the concrete foundation 206. The concrete foundation 206 serves as the bottom foundation of the solid-state heat storage device 21.

[0027] The refractory material 202 is installed on the outside of the steel structure frame 201. The refractory material 202 has inlets and outlets for the heating medium corresponding to the steel structure frame 201. The refractory material 202 is used for heat insulation.

[0028] Preferably, the steel frame 201 is made of chromium-nickel austenitic stainless steel, nickel-based high-temperature alloy steel, cobalt-based high-temperature alloy steel or ferritic heat-resistant steel with a temperature resistance of >600℃; the steel bar 203 is made of chromium-nickel austenitic stainless steel, nickel-based high-temperature alloy steel, cobalt-based high-temperature alloy steel or ferritic heat-resistant steel with a temperature resistance of >600℃.

[0029] Preferably, the electric heating element 204 is made of one of the following materials: nickel-chromium wire, iron-chromium-aluminum wire, nickel-iron wire, and nickel-copper wire.

[0030] In addition to the generator 14, the power generation system 1 also includes a boiler 11, a high-pressure cylinder 12 of the steam turbine, and a medium- and low-pressure cylinder 13 of the steam turbine. The boiler 11 is used to provide steam to the high-pressure cylinder 12 and the medium- and low-pressure cylinder 13 of the steam turbine, thereby enabling the high-pressure cylinder 12 and the medium- and low-pressure cylinder 13 of the steam turbine to drive the generator 14 to generate electricity.

[0031] Boiler 11 includes a preheater, an evaporator, a superheater, and a reheater. The preheater, evaporator, and superheater are connected in series, and the superheater and reheater are connected in parallel.

[0032] The steam inlet of the high-pressure cylinder 12 of the steam turbine is connected to the superheater outlet of the boiler 11, and the steam outlet of the high-pressure cylinder 12 of the steam turbine is connected to the reheater inlet of the boiler 11. The steam inlet of the intermediate and low-pressure cylinder 13 of the steam turbine is connected to the reheater outlet of the boiler 11.

[0033] The generator 14 is connected to the high-pressure cylinder 12 and the medium-low pressure cylinder 13 of the steam turbine. The high-pressure cylinder 12 and the medium-low pressure cylinder 13 of the steam turbine are used to drive the generator 14 to generate electricity. The output terminal of the generator 14 is electrically connected to the power grid 18 and the solid thermal storage device 21, respectively.

[0034] The exhaust port of the low-pressure cylinder 13 of the steam turbine is connected in sequence to the low-pressure heater 15, the deaerator 16 and the high-pressure heater 17. The outlet of the high-pressure heater 17 is connected to the inlet of the preheater of the boiler 11. The high-pressure heater 17 is used to heat the steam under high pressure.

[0035] Therefore, the power generation system 1 includes a boiler 11, a high-pressure cylinder 12 of a steam turbine, a low-pressure cylinder 13 of a steam turbine, a low-pressure heater 15, a deaerator 16, and a high-pressure heater 17 connected sequentially according to the working fluid flow direction. The superheater outlet of the boiler 11 is connected to the steam inlet of the high-pressure cylinder 12 of the steam turbine; the exhaust port of the high-pressure cylinder 12 is connected to the reheater inlet of the boiler 11; the reheater outlet of the boiler 11 is connected to the steam inlet of the low-pressure cylinder 13 of the steam turbine; both the high-pressure cylinder 12 and the low-pressure cylinder 13 of the steam turbine are connected to the generator 14 to jointly drive the generator 14 to generate electricity; the exhaust port of the low-pressure cylinder 13 of the steam turbine is sequentially connected to the low-pressure heater 15 (heating temperature less than 200℃), the deaerator 16, and the high-pressure heater 17 (heating temperature 200℃~350℃); and the outlet of the high-pressure heater 17 is connected to the preheater inlet of the boiler 11. The preheater outlet and superheater inlet of boiler 11 are connected by an evaporator, and the superheater and reheater are connected in parallel.

[0036] The number of generators 14 can be one or more, that is, multiple generators 14 can form a generator set. The boiler 11 is a boiler that can convert water into steam, such as a coal-fired boiler, a gas boiler, or a natural gas boiler.

[0037] The present invention also includes a first valve 31, which is installed on the pipeline between the high-temperature medium outlet of the solid-state heat storage device 21 and the hot medium inlet of the heat exchanger 22; the first valve 31 is used to control the opening and closing of the pipeline between the solid-state heat storage device 21 and the heat exchanger 22.

[0038] The present invention also includes a second valve 32, which is disposed on the pipeline between the high-temperature medium outlet of the solid-state heat storage device 21 and the inlet of the heat circulation fan 23; the second valve 32 is used to control the opening and closing of the pipeline between the solid-state heat storage device 21 and the inlet of the heat circulation fan 23.

[0039] The present invention also includes a third valve 33, which is disposed on the pipeline between the outlet of the high-pressure heater 17 and the cold medium inlet of the heat exchanger 22; the third valve 33 is used to control the opening and closing of the pipeline between the outlet of the high-pressure heater 17 and the cold medium inlet of the heat exchanger 22.

[0040] This utility model also includes a fourth valve 34, which is installed on the pipeline between the cold medium outlet of the heat exchanger 22 and the inlet of the high-pressure cylinder 12 of the steam turbine. The fourth valve 34 is used to control the opening and closing of the pipeline between the cold medium outlet of the heat exchanger 22 and the inlet of the high-pressure cylinder 12 of the steam turbine.

[0041] This utility model also includes a fifth valve 35, which is installed on the heat exchanger 22 cold medium inlet and the external heat demand terminal heating return water pipeline 24. The fifth valve 35 is used to control the opening and closing of the heating return water pipeline 24.

[0042] The working process and principle of this utility model are as follows:

[0043] When the generator set (i.e., generator 14) needs to reduce load and regulate peak load, a portion of the electrical energy is drawn from the generator 14's outlet into the steel heat storage and release subsystem 2, thereby reducing the amount of electricity fed into the grid and achieving the purpose of reducing output and regulating peak load. Simultaneously, the electrical energy entering the steel heat storage and release subsystem 2 provides energy to the electric heating element 204, starting to heat the heat medium in the steel rod 203 within the solid-state heat storage device 21. The circulating fan 23 is started, the first valve 31 is closed, and the second valve 32 is opened. The circulating fan 23 circulates the heat medium, which flows in the flow channel space 205 between the electric heating element 204, the steel structure frame 201, and the steel rod 203. The heat energy generated by the electric heating element 204 is used to heat the steel rod 203 through convection and radiation, thus storing the heat energy. By controlling the amount of electricity drawn out, the unit load can be controlled downwards, realizing the transfer of electrical energy to heat energy.

[0044] When the generator set does not require load reduction, the third valve 33 on the pipeline from the outlet of the high-pressure heater 17 to the heat exchanger 22 is opened, and part of the high-pressure feedwater is drawn from the outlet of the high-pressure heater 17 into the heat exchanger 22 of the steel heat storage and release subsystem 2. The first valve 31 of the steel heat storage and release subsystem 2 is opened, and the second valve 32 is closed. The circulating fan 23 carries the heat from the solid-state heat storage device 21 into the heat exchanger 22, where it exchanges heat with the feedwater (the high-pressure feedwater drawn from the outlet of the high-pressure heater 17) to generate steam. At the same time, the fourth valve 34 on the steam pipeline is opened to send the steam into the high-pressure cylinder 12 of the steam turbine and generate electricity through the generator 14, thereby increasing the unit output while keeping the boiler 11 load unchanged. Meanwhile, for periods when there is a need for external heating, the fifth valve 35 of the heating return water pipeline 24 is opened, allowing the heating return water to enter the heat exchanger 22 and be heated to qualified parameters by the heat medium. The hot water / steam is then supplied to the outside through the external heating pipeline 25. By controlling the feed water flow rate of the high-pressure heater 17 and the return water flow rate, the unit load can be rapidly increased, and the heat energy can be transferred to electrical energy.

Claims

1. A steel heat storage and power generation coupling system, characterized in that, include: A heat storage passage is provided around the solid-state heat storage device (21) and a heat release passage is composed of the solid-state heat storage device (21) and the heat exchanger (22); The input terminal of the electric heating element (204) of the solid thermal storage device (21) is connected to the output terminal of the generator (14) of the power generation system (1) via a cable; The heat storage passage is as follows: the high temperature medium inlet and the high temperature medium outlet of the solid heat storage device (21) are connected by a connecting pipe. The solid heat storage device (21) is used to receive the electrical energy of the power generation system (1) when the power generation system (1) needs to reduce the load, and then convert the electrical energy into heat energy. The heat release pathway is as follows: the heat medium inlet of the heat exchanger (22) is connected to the high temperature medium outlet of the solid heat storage device (21), and the cold medium outlet of the heat exchanger (22) is connected to the steam inlet of the power generation system (1). The heat exchanger (22) is used to receive the heat energy stored in the solid heat storage device (21) when the power generation system (1) does not need to reduce the load, and generate steam by exchanging heat with the feed water from the power generation system (1), and then transport the steam to the power generation system (1) for power generation.

2. The steel-based thermal storage and power generation coupling system according to claim 1, characterized in that, The cold medium outlet of the heat exchanger (22) is also connected to an external heat-demanding terminal via a pipeline.

3. The steel-based thermal energy storage and power generation coupling system according to claim 1, characterized in that, The cold medium inlet of the heat exchanger (22) is connected to the return water of the external heat-demanding terminal through a pipeline.

4. The steel-based thermal energy storage and power generation coupling system of claim 1, wherein, The cold medium inlet of the heat exchanger (22) is also connected to the return water pipeline of the power generation system (1) via a pipeline.

5. The steel-based thermal energy storage and power generation coupling system according to claim 1, characterized in that, The heat medium outlet of the heat exchanger (22) is connected to the high-temperature medium inlet of the solid heat storage device (21) through a pipeline.

6. The steel-based thermal energy storage and power generation coupling system of claim 1, wherein, The solid-state thermal storage device (21) includes: A steel frame (201) is provided with a high-temperature medium inlet and a high-temperature medium outlet; refractory material (202) is provided on the outside of the steel frame (201); A steel rod (203) is located in the inner cavity of the steel structure frame (201) and is used to store thermal energy. The electric heating element (204) is located in the inner cavity of the steel structure frame (201), and the electric heating element (204) and the steel rod (203) are arranged alternately. The electric heating element (204) is used to convert electrical energy into heat energy.

7. The steel-based thermal energy storage and power generation coupling system according to claim 5, characterized in that, The generator system (1) also includes a boiler (11), a high-pressure cylinder (12) of a steam turbine, and a medium- and low-pressure cylinder (13) of a steam turbine; the boiler (11) is used to provide steam to the high-pressure cylinder (12) and the medium- and low-pressure cylinder (13) of the steam turbine, thereby enabling the high-pressure cylinder (12) and the medium- and low-pressure cylinder (13) of the steam turbine to drive the generator (14) to generate electricity.

8. The steel-based thermal energy storage and power generation coupling system of claim 1, wherein, A heat circulation fan (23) is installed on the connecting pipeline.

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