A system and method for realizing peak shaving operation of a thermal power plant by using solid-state hydrogen storage

Abstract

The application discloses a system and method for realizing peak shaving operation of a thermal power plant by using a solid-state hydrogen storage mode, and relates to the technical field of thermal power plants. The system comprises a water electrolysis hydrogen production unit, a solid-state hydrogen storage device, a heat conducting oil circulating pump, a cooler, a boiler, a blower, a steam turbine, a generator and a power grid. Part of hydrogen produced by the water electrolysis hydrogen production unit is used as a reducing agent of a boiler denitration device, and the rest is stored in the solid-state hydrogen storage device. The solid-state hydrogen storage device is connected with the cooler and a boiler bypass flue heat exchanger through a heat conducting oil circulating system to realize heat management of hydrogen absorption and heat release and hydrogen release and heat supply processes. When the thermal power plant needs to operate in a peak shaving mode, hydrogen is produced by using excess power and stored, and when the thermal power plant does not need to operate in the peak shaving mode, hydrogen is provided to the boiler by the solid-state hydrogen storage device. The application can realize the peak shaving operation of the thermal power plant without greatly reducing the unit load, improves energy utilization efficiency, and effectively avoids ammonia escape and equipment corrosion problems of a traditional process by using hydrogen as a denitration reducing agent.

Description

Technical Field

[0001] This invention belongs to the field of power energy technology, specifically relating to a system and method for achieving peak-shaving operation of thermal power plants using solid-state hydrogen storage. Background Technology

[0002] With the large-scale integration of renewable energy sources such as wind and solar power, the power grid faces significant peak-shaving pressure when absorbing renewable energy power due to the volatility and intermittency of its generation. Currently, thermal power units in my country's power system still bear the main peak-shaving responsibility.

[0003] Under traditional peak-shaving methods, thermal power units typically need to operate at low loads for extended periods, which not only reduces unit operating efficiency but may also adversely affect the safe operation of the units.

[0004] On the other hand, ammonia is usually used as a reducing agent in the denitrification process of flue gas from coal-fired boilers. However, ammonia denitrification is prone to ammonia escape and may form ammonium bisulfate, which can cause corrosion to low-temperature heating surfaces.

[0005] Therefore, how to achieve grid peak shaving while ensuring the safe and economical operation of thermal power units, and reduce the problems existing in traditional denitrification technology, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to provide a system and method for peak-shaving operation of thermal power plants using solid-state hydrogen storage, in order to solve the safety and economic problems caused by long-term low-load operation of thermal power units under traditional peak-shaving methods, while using hydrogen as a denitrification reducing agent to reduce ammonia escape and equipment corrosion problems.

[0007] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: Firstly, a system for peak-shaving operation of thermal power plants using solid-state hydrogen storage is provided, including: Electrolysis water hydrogen production unit, solid hydrogen storage device, heat transfer oil circulation pump, cooler, boiler, blower, steam turbine, generator and power grid; The hydrogen outlet of the water electrolysis hydrogen production unit is divided into two paths. One path is connected to the denitrification device of the boiler to provide hydrogen as a reducing agent to the denitrification device. The other path is connected to the hydrogen absorption port of the solid hydrogen storage device to store excess hydrogen in the solid hydrogen storage device. The oxygen outlet of the water electrolysis hydrogen production unit is connected to the blower inlet, and the blower outlet is connected to the boiler to send oxygen as a combustion-supporting gas into the boiler. The hydrogen outlet of the solid hydrogen storage device is connected to the denitrification device of the boiler, and is used to supply hydrogen to the denitrification device of the boiler when the water electrolysis hydrogen production unit is shut down. The solid hydrogen storage device is equipped with a heat exchanger. The heat transfer oil outlet of the solid hydrogen storage device is connected to the heat transfer oil circulation pump inlet. The heat transfer oil circulation pump outlet is selectively connected to the cooler inlet or the heat exchanger inlet in the boiler bypass flue through a switching pipeline. Both the cooler outlet and the bypass flue heat exchanger outlet are connected to the heat transfer oil inlet of the solid hydrogen storage device.

[0008] Optionally, the denitrification device of the boiler is a selective catalytic reduction denitrification device that uses hydrogen as a reducing agent.

[0009] Optionally, the solid hydrogen storage device is equipped with a heat exchanger that exchanges heat with the heat transfer oil, which is used to remove the heat released by the reaction during the hydrogen absorption stage and to provide the required heat during the hydrogen release stage.

[0010] Optionally, a flue gas-thermal oil heat exchanger is installed in the boiler bypass flue to heat the thermal oil using boiler flue gas.

[0011] Optionally, baffles and regulating baffles are installed at the inlet and outlet of the boiler bypass flue to regulate the flue gas flow rate in the bypass flue.

[0012] Optionally, the cooler uses condensate from the power plant's thermal system as the cooling medium.

[0013] Optionally, the condensate inlet of the cooler is connected to the condensate extraction point of the power plant, and the condensate outlet is connected to the condensate return point.

[0014] Secondly, a method for peak-shaving operation of thermal power plants using solid-state hydrogen storage is provided, which is implemented using the aforementioned system and includes the following steps: When a thermal power plant needs to operate for peak shaving: The excess electricity from the power plant is used to drive the water electrolysis hydrogen production unit to produce hydrogen through water electrolysis. Part of the generated hydrogen is sent to the boiler denitrification unit as a reducing agent, and the rest of the hydrogen is sent to the solid hydrogen storage unit for storage. The heat released during the hydrogen absorption stage of the solid hydrogen storage unit is carried away by heat transfer oil and returned to the solid hydrogen storage unit after being cooled by a cooler. When thermal power plants do not require peak shaving: When the water electrolysis hydrogen production unit is shut down, the solid hydrogen storage device releases the stored hydrogen and delivers it to the boiler denitrification device as a reducing agent. At the same time, the heat transfer oil absorbs the heat of the flue gas through the heat exchanger in the boiler bypass flue and returns to the solid hydrogen storage device to meet the heat required for the hydrogen release stage.

[0015] Optionally, during peak-shaving operation, the oxygen produced by the water electrolysis hydrogen production unit is sent to the boiler as a combustion-supporting gas via a blower.

[0016] Optionally, the boiler outlet is connected to the turbine inlet, the turbine drives the generator to generate electricity, and the generator outputs electricity in two ways: one is sent to the power grid, and the other is sent to the water electrolysis hydrogen production unit.

[0017] Compared with the prior art, the beneficial effects of the embodiments of this application are: 1. This application sets up an electrolytic water hydrogen production unit, a solid hydrogen storage device, and a heat transfer oil circulation system, and thermally couples the solid hydrogen storage device with the cooler and the boiler bypass flue heat exchanger, so that the thermal power plant can use surplus electricity to produce and store hydrogen during the peak shaving period, and release hydrogen for the denitrification device during the non-peak shaving period, thereby achieving grid peak shaving operation without significantly reducing the unit load.

[0018] 2. This application uses hydrogen as a boiler denitrification reducing agent to replace the traditional ammonia denitrification process, which can effectively avoid the problem of ammonia escape, reduce ammonium bisulfate deposition and corrosion of low-temperature heating surfaces, and improve the safety of boiler system operation.

[0019] 3. This application uses solid-state hydrogen storage to store hydrogen, which has advantages such as high hydrogen storage density, low operating pressure, high safety, and small footprint compared to high-pressure gaseous or liquid hydrogen storage.

[0020] 4. This application achieves energy coupling between the solid-state hydrogen storage hydrogen absorption and release process and the thermal power plant's thermal system through a heat transfer oil circulation system. The reaction heat generated during the hydrogen absorption stage is transferred through a cooler, while the heat required for the hydrogen release stage is provided by flue gas in the boiler bypass flue, thereby improving the overall energy efficiency of the power plant. The heat required for the hydrogen release stage, provided by the flue gas in the boiler bypass flue, not only provides heat for the hydrogen release reaction but also recovers waste heat from the flue gas, reducing the boiler exhaust temperature and thus improving boiler operating efficiency and the overall energy efficiency of the power plant. During the hydrogen absorption stage, the reaction heat is used to heat the condensate, thereby reducing the amount of steam extracted by the turbine and improving turbine efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This illustration shows a structural diagram of a system for peak-shaving operation of a thermal power plant using solid-state hydrogen storage, as provided in an embodiment of this application.

[0023] Illustration: 1. Electrolysis of water to produce hydrogen; 2. Solid hydrogen storage device; 3. Heat transfer oil circulation pump; 4. Cooler; 5. Boiler; 51. Denitrification device; 52. Bypass flue; 6. Blower; 7. Steam turbine; 8. Generator; 9. Power grid. Detailed Implementation

[0024] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0025] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0027] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0028] Please see Figure 1 As shown, this embodiment provides a system for peak-shaving operation of a thermal power plant using solid-state hydrogen storage, including a water electrolysis hydrogen production unit 1, a solid-state hydrogen storage device 2, a heat transfer oil circulation pump 3, a cooler 4, a boiler 5, a blower 6, a steam turbine 7, a generator 8, and a power grid 9.

[0029] The hydrogen produced by the water electrolysis hydrogen production unit 1 is divided into two streams: one stream enters the denitrification device 51 of boiler 5 as a reducing agent, and the other stream enters the solid-state hydrogen storage device 2 for storage. The solid-state hydrogen storage device 2 is equipped with a heat exchanger and is connected to external heat exchange equipment via a heat transfer oil circulation system. This structure allows for the storage of excess hydrogen during peak-shaving periods and the release of hydrogen for denitrification during off-peak periods, thus achieving synergy between peak-shaving and hydrogen energy utilization.

[0030] In this application, the outlet of the heat transfer oil circulation pump 3 has different flow paths depending on the power plant's operating status. When the power plant is in peak-shaving operation and the solid hydrogen storage device 2 is in the hydrogen absorption stage, the outlet of the heat transfer oil circulation pump 3 is connected to the inlet of the cooler 4, and the heat transfer oil that absorbs heat and heats up in the solid hydrogen storage device 2 is transported to the cooler 4 for cooling via the heat transfer oil circulation pump 3. When the power plant does not need peak-shaving operation and the solid hydrogen storage device 2 is in the hydrogen release stage, the outlet of the heat transfer oil circulation pump 3 is connected to the heat exchanger inlet in the bypass flue 52 of the boiler 5, and the heat transfer oil that releases heat and cools down in the solid hydrogen storage device 2 is heated by high-temperature flue gas in the bypass flue 52 of the boiler 5.

[0031] In some embodiments, the denitrification device 51 of the boiler 5 is a selective catalytic reduction denitrification device using hydrogen as a reducing agent. Using hydrogen as a reducing agent can avoid the ammonia escape problem existing in the traditional ammonia denitrification method, reduce ammonium bisulfate deposition, and improve the reliability of equipment operation.

[0032] In some embodiments, the solid hydrogen storage device 2 is equipped with a heat exchanger that exchanges heat with the heat transfer oil. During the hydrogen absorption phase, the heat exchanger removes the heat released by the reaction, and during the hydrogen release phase, it provides the heat required for the reaction. This structure ensures that the solid hydrogen storage material operates within a suitable temperature range, thereby improving hydrogen storage and release efficiency.

[0033] In some embodiments, a flue gas-thermal oil heat exchanger is installed in the bypass flue duct 52 of the boiler 5 to heat the thermal oil using the flue gas from the boiler 5. When the solid hydrogen storage device 2 is in the hydrogen release stage, the thermal oil absorbs heat in the flue gas heat exchanger and returns to the solid hydrogen storage device 2 to provide the heat required for the hydrogen release reaction, thereby realizing energy recovery and utilization.

[0034] In some embodiments, baffles and regulating baffles are provided at the inlet and outlet of the bypass flue duct 52 of the boiler 5 to regulate the flow rate of flue gas entering the bypass flue duct 52. By adjusting the opening of the baffles, the heat exchange capacity of the flue gas heat exchanger can be controlled, thereby regulating the temperature conditions of the hydrogen storage and release process.

[0035] In some embodiments, the cooler 4 uses condensate from the power plant's thermal system as the cooling medium. During the hydrogen absorption stage of the solid hydrogen storage device 2, the cooler 4 removes the heat released from the reaction, cooling the heat transfer oil before it returns to the solid hydrogen storage device 2. This method can fully utilize the existing thermal system of the power plant and improve the overall energy utilization efficiency of the system.

[0036] By using the condensate in the power plant's thermal system as a cooling medium, the heat released by the hydrogen absorption reaction can be used to heat the condensate, thereby reducing the steam extraction volume of turbine 7 and improving the efficiency of turbine 7.

[0037] In some embodiments, the condensate inlet of the cooler 4 is connected to the power plant's condensate extraction point, and the condensate outlet is connected to the condensate return point. In this way, the heat released by the hydrogen absorption reaction can be carried away by the condensate, thereby reducing the steam extraction rate of the turbine 7 and improving the efficiency of the turbine 7.

[0038] In other embodiments of this application, a method for peak-shaving operation of a thermal power plant using the above-described system is provided. When the thermal power plant needs to operate during peak shaving, excess electricity is used to drive the water electrolysis hydrogen production unit 1 to produce hydrogen. Part of the generated hydrogen is transported to the denitrification device 51 of the boiler 5, and the other part is stored in the solid hydrogen storage device 2. At the same time, the heat generated during the hydrogen absorption process is carried away by heat transfer oil and cooled by the cooler 4. When the thermal power plant does not need to operate during peak shaving, the water electrolysis hydrogen production unit 1 stops operating, the solid hydrogen storage device 2 releases the stored hydrogen for use by the denitrification device 51, and at the same time, the heat transfer oil circulation pump 3 sends the heat transfer oil to the heat exchanger in the bypass flue duct 52 of the boiler 5. After absorbing the heat of the high-temperature flue gas, the oil returns to the solid hydrogen storage device 2 to provide the required heat for the hydrogen release reaction.

[0039] In some embodiments of this application, during peak-shaving operation, the oxygen generated by the water electrolysis hydrogen production unit 1 is sent to the boiler 5 as a combustion-supporting gas through the blower 6, thereby improving the combustion efficiency of the boiler 5 and further improving the energy utilization rate.

[0040] In some embodiments of this application, the steam generated by boiler 5 enters steam turbine 7 to drive generator 8 to generate electricity. Part of the electricity output by generator 8 is transmitted to grid 9, and the other part is transmitted to water electrolysis hydrogen production unit 1. When the power plant has surplus electricity, it can be used for hydrogen production and energy storage, thereby realizing the conversion and regulation between electrical energy and hydrogen energy.

[0041] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A system for peak-shaving operation of a thermal power plant using solid-state hydrogen storage, characterized in that, include: Electrolysis water hydrogen production unit, solid hydrogen storage device, heat transfer oil circulation pump, cooler, boiler, blower, steam turbine, generator and power grid; The hydrogen outlet of the water electrolysis hydrogen production unit is divided into two paths. One path is connected to the denitrification device of the boiler to provide hydrogen as a reducing agent to the denitrification device. The other path is connected to the hydrogen absorption port of the solid hydrogen storage device to store excess hydrogen in the solid hydrogen storage device. The oxygen outlet of the water electrolysis hydrogen production unit is connected to the blower inlet, and the blower outlet is connected to the boiler to send oxygen as a combustion-supporting gas into the boiler. The hydrogen outlet of the solid hydrogen storage device is connected to the denitrification device of the boiler, and is used to supply hydrogen to the denitrification device of the boiler when the water electrolysis hydrogen production unit is shut down. The solid hydrogen storage device is equipped with a heat exchanger. The heat transfer oil outlet of the solid hydrogen storage device is connected to the heat transfer oil circulation pump inlet. The heat transfer oil circulation pump outlet is selectively connected to the cooler inlet or the heat exchanger inlet in the boiler bypass flue through a switching pipeline. Both the cooler outlet and the bypass flue heat exchanger outlet are connected to the heat transfer oil inlet of the solid hydrogen storage device.

2. The system according to claim 1, characterized in that: The denitrification device of the boiler is a denitrification device that uses hydrogen as a reducing agent.

3. The system according to claim 1, characterized in that: The solid hydrogen storage device is equipped with a heat exchanger that exchanges heat with the heat transfer oil, which is used to remove the heat released by the reaction during the hydrogen absorption stage and to provide the required heat during the hydrogen release stage.

4. The system according to claim 1, characterized in that: A flue gas-thermal oil heat exchanger is installed in the boiler bypass flue to heat the thermal oil using boiler flue gas.

5. The system according to claim 4, characterized in that: The boiler bypass flue is equipped with baffles and regulating baffles at the inlet and outlet to regulate the flue gas flow rate in the bypass flue.

6. The system according to claim 1, characterized in that: The cooler uses condensate from the power plant's thermal system as the cooling medium.

7. The system according to claim 6, characterized in that: The condensate inlet of the cooler is connected to the condensate extraction point of the power plant, and the condensate outlet is connected to the condensate return point.

8. A method for achieving peak-shaving operation of a thermal power plant using solid-state hydrogen storage, characterized in that, The system described in any one of claims 1-7 is implemented by comprising the following steps: When a thermal power plant needs to operate for peak shaving: The excess electricity from the power plant is used to drive the water electrolysis hydrogen production unit to produce hydrogen through water electrolysis. Part of the generated hydrogen is sent to the boiler denitrification unit as a reducing agent, and the remaining hydrogen is sent to the solid hydrogen storage unit for storage. The heat released during the hydrogen absorption stage of the solid hydrogen storage unit is carried away by heat transfer oil and returned to the solid hydrogen storage unit after being cooled by a cooler. The cooler uses condensate from the power plant's thermal system as the cooling medium. The condensate inlet is connected to the power plant's condensate extraction point, and the condensate outlet is connected to the condensate return point. When thermal power plants do not require peak shaving: When the water electrolysis hydrogen production unit is shut down, the solid hydrogen storage device releases the stored hydrogen and delivers it to the boiler denitrification device as a reducing agent. At the same time, the heat transfer oil absorbs the heat of the flue gas through the heat exchanger in the boiler bypass flue and returns to the solid hydrogen storage device to meet the heat required for the hydrogen release stage.

9. The method according to claim 8, characterized in that: During peak-shaving operation, the oxygen produced by the water electrolysis hydrogen production unit is sent to the boiler as a combustion-supporting gas via a blower.

10. The method according to claim 8, characterized in that: The boiler outlet is connected to the turbine inlet. The turbine drives the generator to generate electricity. The generator outputs electricity in two ways: one is sent to the power grid, and the other is sent to the water electrolysis hydrogen production unit.

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