Combined energy storage coupling heat network auxiliary thermal power unit device and method

Abstract

This invention relates to the power grid field, specifically to a combined energy storage coupled heating network auxiliary thermal power unit device and method. It includes: a dispatch control platform; a phase change thermal storage and heat exchange unit connected to the dispatch control platform; a feedwater system connected to the phase change thermal storage and heat exchange unit; and a steam drum, one end of which is connected to a superheater, and the other end to the phase change thermal storage and heat exchange unit. The phase change thermal storage and heat exchange unit of this invention can achieve independent storage at medium and low temperatures and high temperatures, facilitating temperature rise control by the dispatch control platform without requiring an additional low-temperature molten salt pump or a complex control system. The solid thermal storage unit, phase change thermal storage container, and high-temperature molten salt storage tank of this invention can match the heat requirements of the preheating, evaporation, and superheating sections required for the steam generation process of the heating network main pipe, and the matching of steam generation parameters with the steam of the heating network main pipe can be achieved using the feedwater system.

Description

Technical Field

[0001] This invention relates to the field of power grids, and more specifically to a combined energy storage coupled heating network auxiliary thermal power unit device and method. Background Technology

[0002] Grid peak shaving refers to the service provided by generator sets to adjust their output in a planned manner and at a certain adjustment rate to track load peak-valley changes. The main purpose of peak shaving is to maintain power balance, keep the system stable, and solve the problem of daily peak-valley load differences in the power grid, that is, the fluctuations in load between peaks and troughs throughout the day. Grid frequency regulation, on the other hand, refers to the process of adjusting the output of generator sets to keep the grid frequency within a specified range. Frequency is an important parameter reflecting power quality, and the role of frequency regulation is to cope with short-term, rapid load fluctuations and maintain the stability of the system frequency.

[0003] In existing technologies, during peak shaving or frequency regulation, the rapid changes in load demand or the volatility of energy supply can easily cause significant fluctuations in steam pressure, flow rate, or temperature during the adjustment process of the heating network, thus affecting the stability of the steam supply. When steam supply fluctuations occur, the heating temperature becomes unstable, affecting the user's heating experience. More seriously, after steam supply fluctuations occur, operators need to constantly adjust the steam supply parameters and equipment operating status to maintain heating quality. This high-intensity real-time control not only increases the labor intensity and work pressure of operators, but may also lead to over-adjustment or under-adjustment during the control process. This not only increases the operating cost of the heating system, but also exacerbates unnecessary energy consumption, leading to resource waste and increased costs. Summary of the Invention

[0004] To address the problems mentioned in the prior art, this invention proposes a combined energy storage coupled heating network auxiliary thermal power unit device and method. Through the set phase change heat storage and heat conversion units, it can meet the frequency regulation or peak regulation requirements of the power grid. At the same time, when the steam supply of the heating network fluctuates during operation, this device can achieve stable steam supply of the heating network.

[0005] To achieve the above objectives, the present invention provides a combined energy storage coupled heating network auxiliary thermal power unit device, comprising:

[0006] Dispatch and control platform;

[0007] Phase change heat storage and heat transfer unit, which is connected to the dispatch and control platform;

[0008] The water supply system is connected to the phase change heat storage and heat transfer unit;

[0009] The steam drum is connected at one end to the superheater and at the other end to the phase change heat storage and heat transfer unit.

[0010] The superheater is connected to the phase change heat storage and heat transfer unit, and also to the main pipe of the heating network.

[0011] Preferably, the phase change heat storage and heat transfer unit includes a medium-low temperature heater, a solid heat storage unit connected to the medium-low temperature heater, a phase change heat storage container connected to the solid heat storage unit, a high-temperature molten salt storage tank, and a high-temperature electric heater.

[0012] Preferably, the phase change heat storage container contains molten salt, and the phase change heat storage container is connected to a high-temperature molten salt storage tank through a liquid phase self-overflow pipe.

[0013] Preferably, it also includes an embedded steam generator disposed in the phase change heat storage and heat transfer unit, the embedded steam generator being connected to the water supply system.

[0014] Preferably, a forced circulation pump is provided between the steam drum and the water supply system.

[0015] Preferably, a pressure self-balancing check valve is provided between the heating network main pipe and the superheater.

[0016] Preferably, the dispatch control platform includes an instruction receiving module, an analysis module, a calculation module, a dispatch control module, and a pressure analysis module.

[0017] Preferably, the main heating network pipe is connected to the heating user's network.

[0018] The method of using a combined energy storage coupled with a heating network to assist thermal power units involves the dispatch control platform activating a low-temperature heater to heat a solid thermal storage unit when the power grid needs peak shaving or frequency regulation. The solid thermal storage unit then transfers heat to a phase change thermal storage container. The molten salt in the phase change thermal storage container is heated and then transferred to a high-temperature molten salt storage tank. The dispatch control platform then activates a high-temperature heater. Through the low-temperature heater and the high-temperature electric heater, the peak shaving or frequency regulation needs of the power grid are met, and pressure stability is achieved.

[0019] Preferably, after the pressure stabilizes, the feedwater system generates steam through an embedded steam generator, and the steam enters the steam drum to maintain pressure stability; when the pressure of the heat user network fluctuates, the pressure of the heat network main pipe drops, and the steam in the steam drum is quickly heated by the superheater and delivered to the heat network main pipe to achieve stable steam supply parameters.

[0020] Compared with the prior art, the present invention achieves the following technical effects:

[0021] Compared with existing peak shaving or frequency regulation processes in heating networks, the phase change heat storage and heat exchange unit of this invention can achieve independent heat storage at medium and low temperatures and high temperatures, facilitating temperature rise control by the dispatching and control platform. Secondly, it eliminates the need for additional low-temperature molten salt pumps, making the overall system structure relatively simple and reducing the overall system cost. In addition, the solid heat storage unit, phase change heat storage container, and high-temperature molten salt storage tank in the device can match the heat requirements of the preheating section, evaporation section, and superheating section required for the steam generation process of the heating network header. By utilizing the feedwater system, the steam generation parameters can be matched with the steam of the heating network header, reducing steam supply fluctuations caused by peak shaving or frequency regulation in existing heating networks, achieving stable steam supply, and thus ensuring stable heating temperature and improving the user's heating experience.

[0022] The steam drum in this invention only needs to meet the startup time of the feedwater system, without needing to store excessive steam for pressure stabilization. The heat required for the steam comes from the phase change heat storage and heat exchange unit. Compared with the existing peak shaving or frequency regulation process of the heating network, it solves the problem of the huge demand on the pressure vessel of the steam drum in the existing heating network for steam pressure stabilization. It can not only achieve steam pressure stabilization, but also reduce the pressure on operators during regulation. In addition, since the steam pressure can be kept stable, it can reduce the over-regulation or under-regulation problems that occur in the existing heating network during the regulation process.

[0023] Compared with the existing frequency regulation or peak regulation process of heating networks, the phase change heat storage and heat exchange unit set in the system of the present invention can store heat during peak regulation or frequency regulation. The stored heat energy can enter the heating network main pipe, thereby realizing all-time regulation and solving the problem that the existing heating network cannot be regulated in real time. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0025] Reference numerals in the attached diagram: 1. Dispatch and control platform; 2. Phase change heat storage and heat transfer unit; 3. Steam drum; 4. Superheater; 5. Main pipe of the heating network; 6. Water supply system; 7. Heat user network; 8. Forced circulation pump; 9. Pressure self-balancing check valve; 10. Water flow regulating valve; 201. Medium and low temperature heater; 202. High temperature electric heater; 203. High temperature molten salt storage tank; 204. Liquid phase self-overflow pipeline; 205. Phase change heat storage container. Detailed Implementation

[0026] The embodiments of this application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. Rather, the embodiments of this application include all variations, modifications, and equivalents falling within the spirit and scope of the appended claims.

[0027] Examples of this application are described in detail below, with examples shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The examples described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0028] like Figure 1 As shown, the combined energy storage coupled heating network auxiliary thermal power unit device of the present invention includes:

[0029] Dispatch and control platform 1, which is connected to the heating network; phase change heat storage and heat transfer unit 2, which is connected to dispatch and control platform 1; water supply system 6, which is connected to phase change heat storage and heat transfer unit 2; steam drum 3, which is connected at one end to superheater 4 and at the other end to phase change heat storage and heat transfer unit 2; superheater 4, which is connected to phase change heat storage and heat transfer unit 2 and also to the heating network main pipe 5.

[0030] like Figure 1 As shown, the phase change heat storage and heat transfer unit 2 specifically includes a low-temperature heater 201, a solid heat storage unit, a phase change heat storage container 205, a high-temperature molten salt storage tank 203, and a high-temperature electric heater 202; wherein the low-temperature heater 201 is connected to the solid heat storage unit, the solid heat storage unit is connected to the phase change heat storage container 205, the phase change heat storage container 205 is connected to the high-temperature molten salt storage tank 203 through a liquid phase self-overflow pipe 204, and the high-temperature electric heater 202 is connected to the high-temperature molten salt storage tank 203.

[0031] In this embodiment, when the power grid issues a peak-shaving or frequency-regulating command, the command is transmitted to the dispatch control platform 1. The dispatch control platform 1 controls the low-temperature heater 201 to heat the fixed thermal storage unit. The heat generated by the solid thermal storage unit is conducted to the phase change thermal storage container 205, thereby heating the molten salt in the phase change thermal storage container 205. The heated molten salt flows into the high-temperature molten salt storage tank 203 through the liquid phase overflow pipe 204. According to the power grid command and the temperature rise of the molten salt, the dispatch control platform 1 adjusts the low-temperature heater 201 and the high-temperature electric heater 202 to... The temperature rise is distributed, and the molten salt in the high-temperature molten salt storage tank 203 is heated to a high temperature for storage, so as to meet the peak shaving and frequency regulation requirements of the power grid and store heat. At this time, the dispatch control platform 1 adjusts the medium and low temperature heater 201 and the high temperature electric heater 202 according to the power grid command and the temperature rise of the molten salt to distribute the temperature rise, thereby meeting the peak shaving or frequency regulation requirements of the power grid. While meeting the peak shaving or frequency regulation requirements of the power grid, the high temperature electric heater 202 will also heat the molten salt in the high-temperature molten salt storage tank 203, so that the high-temperature molten salt storage tank 203 will complete the high-temperature heat storage.

[0032] The medium-low temperature heater 201 used in this embodiment is a heating device that can raise the temperature of a liquid to a certain level (usually below 100°C). Its operating temperature range is usually low. In this embodiment, the medium-low temperature heater 201 heats the solid heat storage unit, thereby raising the temperature of the solid heat storage unit.

[0033] In this embodiment, the fixed heat storage unit is a device for storing and releasing thermal energy. The fixed heat storage unit stores thermal energy through the heat storage material filled inside, such as paraffin, water, or molten salt, and releases this thermal energy when needed. This can balance the time mismatch between energy supply and demand and improve energy utilization efficiency. When the fixed heat storage unit receives heat from the medium-low temperature heater 201, the heat storage material in the fixed heat storage unit absorbs the heat energy, causing the temperature of the heat storage material to gradually rise. The heat generated by the rise is transferred to the phase change heat storage container 205 to achieve heat transfer.

[0034] In this embodiment, the phase change thermal storage container 205 is an energy storage device based on phase change energy storage material. It utilizes the characteristic of a substance absorbing or releasing a large amount of latent heat during the phase change process to store and release heat. The phase change thermal storage container 205 utilizes this characteristic to cause the phase change material to absorb heat and undergo a phase change when heat energy needs to be stored, storing the heat energy in the form of latent heat in the material; when heat energy needs to be released, the phase change material undergoes a reverse phase change to release the stored latent heat. In this embodiment, the phase change material of the phase change thermal storage container 205 is preferably solid molten salt. Solid molten salt has a high energy storage density and good thermal stability. The solid molten salt is heated by heat from the solid thermal storage unit in the phase change thermal storage container 205. During the heating process, the solid molten salt will become liquid molten salt. Due to the difference in density, the liquid molten salt will rise and the solid molten salt will sink. The resulting liquid molten salt will expand in volume. The expanded liquid molten salt will flow into the high-temperature molten salt storage tank 203 through the liquid phase overflow pipe 204 and be stored in the high-temperature molten salt tank.

[0035] The liquid phase self-overflow pipe 204 in this embodiment is an automatically controlled fluid management device. It controls the flow of liquid by setting a preset liquid level. When the liquid reaches or exceeds this level, the excess liquid will automatically flow out through the overflow pipe, thereby keeping the liquid level in the container or system within a safe range. In this embodiment, in order to ensure the amount of liquid molten salt flowing into the high-temperature molten salt storage tank 203, the liquid phase self-overflow pipe 204 is used to transport the liquid molten salt.

[0036] In this embodiment, the high-temperature electric heater 202 generates heat through a high-temperature resistance wire evenly distributed inside a seamless stainless steel tube. When current passes through the resistance wire, the resistance wire heats up, and the generated heat diffuses to the surface of the metal tube through the densely packed crystalline magnesium oxide powder filling the gaps, and is then transferred to the heated component or the air, thereby achieving the purpose of heating.

[0037] In this embodiment, a forced circulation pump 8 is installed between the steam drum 3 and the water supply system 6. The purpose is to ensure that the steam water level in the steam drum 3 can be stably maintained within a predetermined normal range. This is because the water level in the steam drum 3 is directly related to the safe operation and efficiency of the entire system. If the water level is too high, it may cause water to be carried in the steam, thereby affecting the steam quality and damaging the equipment. If the water level is too low, it may cause dry burning, resulting in equipment damage or even safety accidents. Therefore, the forced circulation pump 8 is introduced. Its main function is to actively regulate the water level in the steam drum 3 by increasing the flow rate and power of the water circulation. Specifically, when the dispatch control platform 1 detects that the water level in the steam drum 3 exceeds the set upper limit, it will start the forced circulation pump 8 to control the water level.

[0038] In this embodiment, a water flow regulating valve 10 is provided between the water supply system 6 and the phase change heat storage and heat transfer unit 2. The water flow regulating valve 10 serves as a component connecting the water supply system 6 and the phase change heat storage and heat transfer unit 2. Its main function is to dynamically adjust and control the water flow rate according to the requirements of the scheduling and control platform 1 or preset conditions, so as to achieve precise water flow control between the water supply system 6 and the phase change heat storage and heat transfer unit 2, thereby improving the heat storage efficiency and system stability.

[0039] The purpose of the superheater 4 in the embodiment is that after the water supply system 6 passes through the phase change heat storage and heat conversion unit 2, the steam generated will be stored in the steam drum 3. The steam in the steam drum 3 will be heated by the superheater 4 and then transported to the heating network main pipe 5.

[0040] In this embodiment, the superheater 4 is specifically connected to the high-temperature molten salt storage tank 203 in the phase change heat storage and heat transfer unit 2. A high-temperature pump is installed between the superheater 4 and the high-temperature molten salt storage tank 203 to transfer the heat stored in the high-temperature molten salt storage tank 203 to the superheater 4 by pumping. In this embodiment, the superheater 4 is preferably a convection superheater 4, which uses the high-temperature molten salt tank to provide a heat source, thereby raising the steam temperature to meet the quality requirements of the heating network header 5 and sending it into the heating network header 5 to stabilize the fluctuating steam supply pressure of the heating network.

[0041] In this embodiment, a pressure self-balancing check valve 9 is installed between the superheater 4 and the steam supply header according to the steam flow direction. To ensure the safety, efficiency and stability of steam during transmission, a pressure self-balancing check valve 9 is arranged at the connection between the superheater 4 and the steam supply header. The pressure self-balancing check valve 9 can automatically adjust the steam flow direction and provide additional safety assurance under specific conditions (such as pressure fluctuations). Specifically, when the pressure in the steam supply header drops instantaneously, the valve can quickly sense this change and automatically open after detecting the pressure difference, thereby allowing saturated steam from the steam drum 3 to pass through quickly after being heated by the superheater 4. This process effectively alleviates the problem of unstable steam supply that may be caused by pressure drop in the steam supply header. It can respond quickly to sudden situations such as pressure fluctuations and ensure the stability and reliability of steam supply parameters by automatically adjusting the steam flow direction and heating process.

[0042] In this embodiment, the dispatch control platform 1 includes an instruction receiving module, an analysis module, a calculation module, a dispatch control module, and a pressure analysis module. The instruction receiving module is used to receive power grid dispatch instructions.

[0043] Analysis module: Analyzes the state of the electric heating in phase change heat storage and heat transfer unit 2 in the system.

[0044] The calculation module analyzes the amplitude that the calculation system needs to adjust and converts the frequency-modulated power signal into an executable valve opening degree and electric heater load signal.

[0045] Transportation control module: It achieves the tracking of target values ​​through invocation and control.

[0046] Pressure analysis module: Real-time detection of heating network pressure fluctuations. When pressure fluctuations occur in the heating network, the phase change heat storage and heat transfer unit 2, steam drum 3, superheater 4, and feedwater system 6 are used to stabilize the heating network.

[0047] When this device is in use, if the power grid has peak shaving or frequency regulation requirements, the dispatch control platform 1 starts the medium-low temperature heater 201 in the phase change heat storage and heat transfer unit 2 to heat the solid heat storage unit. The heated solid heat storage unit transfers heat to the phase change heat storage container 205, and the solid molten salt in the phase change heat storage container 205 is heated by the heat from the solid heat storage unit. Due to the difference in density, the liquid molten salt in the phase change heat storage container 205 moves upward and the solid molten salt sinks. Moreover, due to the expansion of the liquid molten salt volume, the liquid molten salt will flow into the high temperature molten salt storage tank 203 through the liquid phase overflow pipe 204. At this time, the dispatch control platform 1 starts the high temperature electric heater 202 according to the power grid dispatch instructions and the temperature rise of the molten salt in the high temperature molten salt storage tank 203, and distributes the temperature rise of the high temperature electric heater 202 and the medium-low temperature heater 201. When the high temperature electric heater 202 heats, it will continue to heat the molten salt in the high temperature molten salt storage tank 203 to a high temperature for storage. While fulfilling the peak shaving or frequency regulation requirements of the power grid, it can also store heat.

[0048] When the pressure is stable, the water supply system 6 is turned on, and the water supply system 6 transports water into the phase change heat storage and heat transfer unit 2. After passing through the embedded steam generator in the phase change heat storage and heat transfer unit 2, saturated steam is generated. The saturated steam enters the steam drum 3 and ensures that the water level in the steam drum 3 is within the normal range. When the liquid level in the steam drum 3 is too high, the forced circulation pump 8 needs to be turned on to control the water level so that the water level is always within the normal range. The steam drum 3 stores saturated steam at a certain pressure. Since the saturated pressure corresponding to the phase change temperature of the molten salt in this device can match the steam supply pressure of the heating network main pipe 5, additional pressure control is performed. When the pressure of the heat user network 7 fluctuates, it will cause the pressure of the heating network main pipe 5 to drop. The pressure self-balancing check valve 9 will open automatically, and the saturated steam in the steam drum 3 will be quickly heated by the superheater 4 to the required steam supply parameters of the heating network main pipe 5 to achieve stable steam supply parameters.

[0049] In order to maintain the continuous and stable operation of superheater 4 and ensure that the parameters of the self-balancing steam match the steam supply parameters required by the heating network header 5, the temperature of the molten salt in the high-temperature molten salt storage tank 203 needs to be kept slightly higher than the steam supply temperature. The high-temperature molten salt pump needs to be continuously started to keep superheater 4 at a constant temperature.

[0050] The specific example uses a 2x330MW coal-fired power plant unit as an example. The steam turbine is a 17.75 / 540 / 540 type subcritical, single-stage reheat, three-cylinder, two-exhaust condensing steam turbine. After heating system modification, steam can be extracted from the cold and hot sections of the turbine for external heating, with a total designed heating steam capacity of 140T / h for both units. The regulation capacity of the two units is only 1%Pe / min, that is, a total regulation capacity of 6.6MW / min. By coupling the combined energy storage coupled heating network frequency regulation auxiliary power plant unit device and method of the present invention, the regulation capacity is increased by nearly 2.5 times after the total capacity reaches 10MW.

[0051] It should be noted that in the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0052] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A combined energy storage coupled heating network auxiliary thermal power unit device, characterized in that, include: Dispatch and control platform; Phase change heat storage and heat transfer unit, which is connected to the dispatch and control platform; The water supply system is connected to the phase change heat storage and heat transfer unit; The steam drum is connected at one end to the superheater and at the other end to the phase change heat storage and heat transfer unit. The superheater is connected to the phase change heat storage and heat transfer unit, and also to the main pipe of the heating network. The phase change heat storage and heat transfer unit includes a medium-low temperature heater, a solid heat storage unit connected to the medium-low temperature heater, a phase change heat storage container connected to the solid heat storage unit, a high-temperature molten salt storage tank, and a high-temperature electric heater. The phase change heat storage container is filled with molten salt, and the phase change heat storage container is connected to the high temperature molten salt storage tank through a liquid phase self-overflow pipe; It also includes an embedded steam generator located in the phase change heat storage and heat transfer unit, wherein the embedded steam generator is connected to the water supply system; The dispatch control platform includes an instruction receiving module, an analysis module, a calculation module, a dispatch control module, and a pressure analysis module.

2. The combined energy storage coupled heating network auxiliary thermal power unit device according to claim 1, characterized in that, A forced circulation pump is installed between the steam drum and the feedwater system.

3. The combined energy storage coupled heating network auxiliary thermal power unit device according to claim 1, characterized in that, A pressure self-balancing check valve is installed between the main heating network pipe and the superheater.

4. The combined energy storage coupled heating network auxiliary thermal power unit device according to claim 1, characterized in that, The main pipe of the heating network is connected to the heating user network.

5. The method for the combined energy storage coupled heating network assisted thermal power unit device according to any one of claims 1 to 4, characterized in that, When the power grid needs peak shaving or frequency regulation, the dispatch control platform starts the medium-low temperature heater to heat the solid thermal storage unit. The solid thermal storage unit transfers heat to the phase change thermal storage container. The molten salt in the phase change thermal storage container is heated and then transferred to the high-temperature molten salt storage tank. The dispatch control platform starts the high-temperature heater. Through the medium-low temperature heater and the high-temperature electric heater, the power grid's peak shaving or frequency regulation needs are met, and pressure stability is achieved.

6. The method for the combined energy storage coupled heating network assisted thermal power unit device according to claim 5, characterized in that, After the pressure stabilizes, the feedwater system generates steam through the embedded steam generator, and the steam enters the steam drum to maintain pressure stability. When the pressure of the heat user network fluctuates, the pressure of the heat network main pipe drops, and the steam in the steam drum is quickly heated by the superheater and delivered to the heat network main pipe to stabilize the steam supply parameters.

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