Pressure stabilization control method, device, equipment and medium for compressed carbon dioxide energy storage system

Abstract

The invention provides a pressure stabilization control method, device, equipment and medium for a compressed carbon dioxide energy storage system, relates to the technical field of compressed energy storage, is applied to the compressed carbon dioxide energy storage system, and comprises a high-pressure gas storage unit with a carbon dioxide pipeline at the bottom end and a liquid pump; the method comprises the following steps: acquiring state data of a high-pressure gas storage unit at an initial moment, and determining thermodynamic parameters at the initial moment according to the state data at the initial moment; according to the thermodynamic parameters and the state data at the initial moment, thermodynamic parameters and state data at the next moment are determined, the thermodynamic parameters and the state data at the moment serve as initial parameters and state data at the next moment to be subjected to iterative calculation, and thermodynamic parameters at each moment and state data at each moment are obtained; and according to the thermodynamic parameters and the state data of each moment, generating a thermodynamic change curve, and according to the thermodynamic change curve, performing frequency conversion control on the operation of the liquid pump. The energy utilization efficiency can be improved.

Description

Technical Field

[0001] The present invention relates to the field of compressed energy storage technology, and in particular to a method, device, equipment and medium for voltage stabilization control of a compressed carbon dioxide energy storage system. Background Art

[0002] Compressed CO2 energy storage uses electricity to compress and store CO2 in geological structures or man-made tanks. When needed, the high-pressure CO2 is released to drive turbines for power generation. This technology is primarily used for large-scale grid energy storage to balance grid loads, increase renewable energy utilization, address the mismatch between supply and demand in the renewable energy power generation industry, and assist in peak-shaving.

[0003] In related technologies, compressed carbon dioxide is released through an expander, converting the stored high-pressure gas energy into mechanical energy, which is then used to generate electricity through a generator. During the release process, supercritical carbon dioxide in compressed carbon dioxide energy storage systems liquefies, necessitating a heating device. To ensure the operating efficiency of the expander, the current main methods are to operate the expander in a sliding pressure mode to ensure isentropic efficiency, or to maintain a stable inlet pressure using a throttle valve. However, the former is difficult to control, making it difficult to maintain a constant output power, while the latter results in significant exergy losses, reducing the system's electrical-to-electrical conversion efficiency. Summary of the Invention

[0004] The present invention aims to solve at least one of the above problems.

[0005] To solve the above problems, the present invention provides a method, device, equipment and medium for voltage stabilization control of a compressed carbon dioxide energy storage system.

[0006] In a first aspect, the present invention provides a method for controlling a pressure of a compressed carbon dioxide energy storage system, which is applied to a compressed carbon dioxide energy storage system. The compressed carbon dioxide energy storage system includes a high-pressure gas storage unit having a carbon dioxide pipeline at its bottom end and a liquid pump disposed at the outlet of the carbon dioxide pipeline. The liquid pump is used to control the energy release pressure of the compressed carbon dioxide energy storage system. The method for controlling the pressure stabilization of the compressed carbon dioxide energy storage system includes: Acquiring state data of the high-pressure gas storage unit at an initial moment, and determining thermodynamic parameters at the initial moment based on the state data at the initial moment; Determining the thermodynamic parameters and the state data at the next moment according to the thermodynamic parameters at the initial moment and the state data at the initial moment, and performing iterative calculations using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and state data at the next moment, to obtain the thermodynamic parameters and the state data at each moment; A thermodynamic change curve is generated according to the thermodynamic parameters at each moment and the state data at each moment, and the operation of the liquid pump is frequency-controlled according to the thermodynamic change curve.

[0007] Optionally, the state data at the initial moment includes the volume of the high-pressure gas storage unit, the temperature value at the initial moment, the pressure value at the initial moment, the gas mass flow rate during the energy release process, the gas density at the initial moment, and the total gas mass at the initial moment, wherein the volume and the gas mass flow rate are fixed; The obtaining of the initial state data of the high-pressure gas storage unit includes: Obtaining the preset volume, the temperature value at the initial moment, the pressure value at the initial moment, and the gas mass flow rate; Determining the gas density at the initial moment using thermodynamic software based on the temperature value and the pressure value at the initial moment; The total mass of the gas at the initial moment is determined according to the volume and the gas density at the initial moment.

[0008] Optionally, the thermodynamic parameters at the initial moment include a specific thermodynamic energy parameter at the initial moment, a specific enthalpy parameter at the initial moment, and a specific entropy parameter at the initial moment; Determining the thermodynamic parameters at the initial moment according to the state data at the initial moment includes: According to the temperature value at the initial moment and the pressure value at the initial moment, the thermodynamic software is used to determine the specific thermodynamic energy parameter at the initial moment, the specific enthalpy parameter at the initial moment, and the specific entropy parameter at the initial moment.

[0009] Optionally, determining the thermodynamic parameters at a next moment and the state data at a next moment based on the thermodynamic parameters at the initial moment and the state data at the initial moment includes: Obtaining the gas mass flow rate of the high-pressure gas storage unit during the energy release process, and determining the total mass of gas in the high-pressure gas storage unit at a next moment based on the gas mass flow rate, and determining the density at a next moment based on the total mass of gas in the high-pressure gas storage unit at the next moment and the volume; According to the law of conservation of energy of unsteady flow in an open system, the specific thermodynamic energy parameters at the next moment are determined; According to the specific thermodynamic energy parameter at the next moment and the density at the next moment, the thermodynamic software is used to respectively determine the temperature value at the next moment, the pressure value at the next moment, the specific enthalpy parameter at the next moment, and the specific entropy parameter at the next moment.

[0010] Optionally, determining the specific thermodynamic energy parameter at the next moment according to the law of conservation of energy of unsteady flow in an open system includes: According to the law of conservation of energy of the unsteady flow of the opening system, the specific thermodynamic energy parameter determination formula is used to determine the specific thermodynamic energy parameter at the next moment. The specific thermodynamic energy parameter determination formula includes: ; in, is the initial moment, is the time interval, For the next moment, is the specific thermodynamic energy parameter at the next moment, m is the total mass of the gas at the initial moment, is the specific thermodynamic energy parameter at the initial moment, mf is the gas mass flow rate, h is the specific enthalpy parameter, is the specific enthalpy parameter of carbon dioxide in saturated liquid state at the pressure at time t, is the total mass of gas in the high-pressure gas storage unit at the next moment.

[0011] Optionally, the thermodynamic change curve includes a dryness change curve, a high-pressure gas storage unit internal pressure change curve, and a liquid pump pressure head change curve. Generating the thermodynamic change curve according to the thermodynamic parameters at each moment and the state data at each moment includes: generating the dryness variation curve according to the thermodynamic parameters at each moment; generating a pressure change curve inside the high-pressure gas storage unit according to the state data at each moment; The liquid pump pressure head variation curve is generated according to the internal pressure variation curve of the high-pressure gas storage unit and the preset outlet pressure value.

[0012] Optionally, the variable frequency control of the operation of the liquid pump according to the thermodynamic change curve includes: determining the state of high-pressure carbon dioxide at the outlet of the high-pressure gas storage unit according to the dryness change curve; The operation of the liquid pump is controlled by frequency conversion according to the high-pressure carbon dioxide state and the pressure head change curve of the liquid pump.

[0013] In a second aspect, the present invention provides a compressed carbon dioxide energy storage system pressure stabilization control device, which is applied to a compressed carbon dioxide energy storage system. The compressed carbon dioxide energy storage system includes a high-pressure gas storage unit with a carbon dioxide pipeline at the bottom and a liquid pump provided at the outlet of the carbon dioxide pipeline. The liquid pump is used to control the energy release pressure of the compressed carbon dioxide energy storage system. The compressed carbon dioxide energy storage system pressure stabilization control device includes: An initial module, configured to obtain state data of the high-pressure gas storage unit at an initial moment, and determine thermodynamic parameters at the initial moment based on the state data at the initial moment; an iteration module, configured to determine the thermodynamic parameters and the state data at the next moment based on the thermodynamic parameters and the state data at the initial moment, and perform iterative calculations using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and the state data at the next moment, to obtain the thermodynamic parameters and the state data at each moment; The control module is used to generate a thermodynamic change curve according to the thermodynamic parameters at each moment and the state data at each moment, and to frequency-control the operation of the liquid pump according to the thermodynamic change curve.

[0014] In a third aspect, the present invention provides an electronic device comprising a memory and a processor; The memory is used to store computer programs; The processor is configured to implement the method for controlling the pressure stabilization of the compressed carbon dioxide energy storage system as described in the first aspect when executing the computer program.

[0015] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system as described in the first aspect is implemented.

[0016] The beneficial effects of the compressed carbon dioxide energy storage system pressure stabilization control method, device, electronic device and storage medium of the present invention are: By arranging the carbon dioxide pipeline and liquid pump at the bottom of the high-pressure gas storage unit, the high-pressure carbon dioxide in the high-pressure gas storage unit can flow out from the bottom of the high-pressure gas storage unit in the form of supercritical state or liquid under the dual effects of gravity and pressure difference. No additional heating device is required to make the high-pressure carbon dioxide flow out, which saves operating costs. By determining the thermodynamic parameters at the initial moment based on the state data of the high-pressure gas storage unit at the initial moment, the thermodynamic parameters at each moment can be accurately calculated, thereby generating a curve of the thermodynamic parameters in the high-pressure gas storage unit changing with time. Then, according to the thermodynamic change curve, the operation of the liquid pump is frequency-controlled, and the pressure of the high-pressure carbon dioxide at the expander inlet during the energy release process of the compressed carbon dioxide energy storage system is more conveniently adjusted and controlled to be constant, thereby reducing exergy loss and improving energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic flow chart of a method for controlling a compressed carbon dioxide energy storage system voltage stabilization according to an embodiment of the present invention; Figure 2A schematic structural diagram of a compressed carbon dioxide energy storage system provided in an embodiment of the present invention; Figure 3 A schematic diagram of gas changes in a compressed carbon dioxide energy storage system provided in an embodiment of the present invention; Figure 4 A schematic diagram of a dryness variation curve provided in an embodiment of the present invention; Figure 5 A schematic diagram of an internal pressure variation curve provided by an embodiment of the present invention; Figure 6 A schematic diagram of a pressure head variation curve of a liquid pump provided in an embodiment of the present invention; Figure 7 A schematic structural diagram of a pressure stabilizing control device for a compressed carbon dioxide energy storage system according to an embodiment of the present invention; Figure 8 A schematic structural diagram of an electronic device provided by an embodiment of the present invention.

[0018] Description of reference numerals: 1. High-pressure gas storage unit; 11. Carbon dioxide pipeline; 12. Ball valve; 2. Liquid pump. DETAILED DESCRIPTION

[0019] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as being limited to the embodiments described herein. Instead, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] It should be understood that the various steps described in the method embodiments of the present invention may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present invention is not limited in this respect.

[0021] The term "including" and its variations used in this document are open inclusions, that is, "including but not limited to"; the term "based on" means "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first", "second", etc. mentioned in the present invention are only used to distinguish different devices, modules or units, and are not used to limit the order or interdependence of the functions performed by these devices, modules or units.

[0022] It should be noted that the modifications of "one" and "multiple" mentioned in the present invention are illustrative rather than restrictive. Those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0023] The names of the messages or information exchanged between multiple devices in the embodiments of the present invention are only used for illustrative purposes and are not used to limit the scope of these messages or information.

[0024] In response to the problems existing in the above-mentioned related technologies, this embodiment provides a method, device, equipment and medium for voltage stabilization control of a compressed carbon dioxide energy storage system.

[0025] The embodiment of the present invention provides a method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system, which is applied to a compressed carbon dioxide energy storage system, such as Figure 2 As shown, the compressed carbon dioxide energy storage system includes a high-pressure gas storage unit 1 with a carbon dioxide pipeline 11 at the bottom and a liquid pump 2 arranged at the outlet of the carbon dioxide pipeline 11. The liquid pump 2 is used to control the energy release pressure of the compressed carbon dioxide energy storage system.

[0026] Specifically, a carbon dioxide pipeline 11 is provided at the bottom of the high-pressure gas storage unit 1 of the compressed carbon dioxide energy storage system. That is, the carbon dioxide outlet in the high-pressure gas storage unit 1 is provided at the bottom, so that the high-pressure carbon dioxide in the high-pressure gas storage unit 1 flows out from the bottom of the high-pressure gas storage unit in a supercritical state or liquid form under the dual effects of gravity and pressure difference. The carbon dioxide pipeline 11 is also provided with a ball valve 12 and a liquid pump 2 in sequence along the direction of high-pressure carbon dioxide release. The ball valve 12 is used to control the gas mass flow rate during the energy release process. By adjusting the opening of the ball valve, the mass flow rate of the carbon dioxide outflow can be accurately controlled to ensure a constant energy release flow rate. The liquid pump 2 can be a corrosion-resistant centrifugal pump, which is used to control the constant energy release pressure of the compressed carbon dioxide energy storage system.

[0027] like Figure 1 As shown, the pressure stabilization control method of the compressed carbon dioxide energy storage system includes: The state data of the high-pressure gas storage unit 1 at the initial moment is acquired, and the thermodynamic parameters at the initial moment are determined according to the state data at the initial moment.

[0028] Specifically, the state data at the initial moment include the volume of the high-pressure gas storage unit 1, the temperature value at the initial moment, the pressure value at the initial moment, the gas mass flow rate during the energy release process, the gas density at the initial moment, and the total gas mass at the initial moment. Among them, the volume, gas mass flow rate, the temperature value at the initial moment, and the pressure value at the initial moment are preset values ​​and can be set according to actual conditions. For example, the volume is set to 80 m 3 The gas mass flow rate is set to 5 kg / s, the initial temperature is set to 308.15 K, and the initial pressure is set to 10 MPa. The volume and gas mass flow rate remain constant, and neither changes with increasing energy release time. Based on the initial state data, thermodynamic parameters at the initial time can be determined using thermodynamic software such as refprop. The initial thermodynamic parameters include the specific thermodynamic energy parameter, the specific enthalpy parameter, and the specific entropy parameter. The specific entropy parameter can be used to verify the accuracy of the calculation process.

[0029] According to the thermodynamic parameters at the initial moment and the state data at the initial moment, the thermodynamic parameters at the next moment and the state data at the next moment are determined, and the thermodynamic parameters at the next moment and the state data at the next moment are used as the initial thermodynamic parameters and state data at the next moment for iterative calculation to obtain the thermodynamic parameters at each moment and the state data at each moment.

[0030] Specifically, based on the thermodynamic parameters at the initial moment and the state data at the initial moment, the thermodynamic parameters at the next moment and the state data at the next moment are determined, and the thermodynamic parameters at the next moment and the state data at the next moment are used as the initial thermodynamic parameters and state data at the next moment for iterative calculation, that is, the obtained thermodynamic parameters at the next moment and the state data at the next moment are used as the data at the current moment, and based on the data at the current moment, the data at the next moment after the current moment is determined, and an iterative cycle calculation is performed to obtain the thermodynamic parameters at each moment and the state data at each moment, that is, the data at each moment in the process from the start to the end of energy release is obtained.

[0031] A thermodynamic change curve is generated according to the thermodynamic parameters at each moment and the state data at each moment, and the operation of the liquid pump 2 is frequency-controlled according to the thermodynamic change curve.

[0032] Specifically, according to the thermodynamic parameters and state data at each moment, a thermodynamic change curve is generated, such as Figure 4-6As shown, the thermodynamic change curve includes a dryness change curve, a pressure change curve inside the high-pressure gas storage unit 1, and a liquid pump pressure head change curve. Dryness refers to the proportion of saturated gaseous carbon dioxide in the gas-liquid coexisting carbon dioxide in the high-pressure gas storage unit 1. The dryness change curve can clearly define the internal state of the high-pressure gas storage unit 1, such as temperature and pressure, and thus determine the state of the compressed carbon dioxide, that is, Figure 3 As shown, as the energy release time increases, when the dryness value is in the interval [0, 1], the high-pressure carbon dioxide in the high-pressure gas storage unit 1 is converted from a supercritical state to a gas-liquid coexistence state, and the gas-liquid boundary moves from the top to the bottom of the high-pressure gas storage unit 1. During this period, the high-pressure carbon dioxide can be released. As the energy release time increases, when it is outside the interval [0, 1], for example, when it is greater than 1, as shown in FIG. Figure 3 As shown, the high-pressure carbon dioxide in the high-pressure gas storage unit 1 is converted from a gas-liquid coexistence state to a gaseous state. At this time, the compressed carbon dioxide release operation is stopped and the energy release process is completed. The internal pressure change curve of the high-pressure gas storage unit 1 refers to the change of the internal pressure of the high-pressure gas storage unit 1 with the energy release time. The liquid pump pressure head change curve refers to the change of the pressure head of the liquid pump with the energy release time. The pressure head of the liquid pump is the difference between the outlet pressure and the inlet pressure of the liquid pump. The outlet pressure is a fixed value and can be set according to actual conditions. For example, the preset outlet pressure value is set to 10 MPa, and the inlet pressure is the same as the internal pressure of the high-pressure gas storage unit 1. Therefore, the liquid pump pressure head change curve can be determined by the outlet pressure and the internal pressure change curve. Then, based on the similarity law and the liquid pump pressure head change curve, the frequency can be determined to control the operation of the liquid pump 2 by frequency conversion, thereby ensuring that the energy release pressure of the high-pressure carbon dioxide in the compressed carbon dioxide energy storage system is constant, that is, the expander inlet pressure is kept constant.

[0033] In this embodiment, the carbon dioxide pipeline 11 and liquid pump 2 disposed at the bottom of the high-pressure gas storage unit 1 allow the high-pressure carbon dioxide within the high-pressure gas storage unit 1 to flow out of the bottom of the high-pressure gas storage unit 1 in a supercritical or liquid state under the dual effects of gravity and pressure differential. No additional heating device is required to cause the high-pressure carbon dioxide to flow out of the top as a gas, thus saving operating costs. Furthermore, by determining the thermodynamic parameters at the initial moment based on the initial state data of the high-pressure gas storage unit 1, the thermodynamic parameters at each moment can be accurately calculated, thereby generating a curve showing the change of the thermodynamic parameters within the high-pressure gas storage unit 1 over the energy release time. Based on this thermodynamic change curve, the operation of the liquid pump 2 is frequency-controlled to maintain a constant energy release pressure of the compressed carbon dioxide energy storage system, that is, to maintain a constant expander inlet pressure, thereby reducing exergy losses and improving electrical-to-electrical conversion efficiency. Furthermore, frequency-controlled operation of the liquid pump can exploit the problem of supercritical carbon dioxide liquefaction within the high-pressure gas storage unit 1 during energy release, thereby enhancing energy utilization efficiency, increasing the minimum operating pressure of the high-pressure gas storage unit 1, and improving the efficiency of the high-pressure gas storage unit's container utilization.

[0034] Optionally, the state data at the initial moment includes the volume of the high-pressure gas storage unit 1, the temperature value at the initial moment, the pressure value at the initial moment, the gas mass flow rate during the energy release process, the gas density at the initial moment, and the total gas mass at the initial moment, wherein the volume and the gas mass flow rate are fixed; The obtaining of the initial state data of the high-pressure gas storage unit 1 includes: Obtaining the preset volume, the temperature value at the initial moment, the pressure value at the initial moment, and the gas mass flow rate; Determining the gas density at the initial moment using thermodynamic software based on the temperature value and the pressure value at the initial moment; The total mass of the gas at the initial moment is determined according to the volume and the gas density at the initial moment.

[0035] Specifically, the volume, the temperature value at the initial moment, the pressure value at the initial moment, and the gas mass flow rate are all preset values. Based on the temperature value at the initial moment and the pressure value at the initial moment, thermodynamic software, such as refprop software, can be used to determine the gas density at the initial moment. Based on the volume and the gas density at the initial moment, the total mass of the gas at the initial moment can be determined using a mass formula. The mass formula includes: ; Where m is the total mass of gas at the initial moment, V is the volume, is the gas density at the initial moment.

[0036] Optionally, the thermodynamic parameters at the initial moment include a specific thermodynamic energy parameter at the initial moment, a specific enthalpy parameter at the initial moment, and a specific entropy parameter at the initial moment; Determining the thermodynamic parameters at the initial moment according to the state data at the initial moment includes: According to the temperature value at the initial moment and the pressure value at the initial moment, the thermodynamic software is used to determine the specific thermodynamic energy parameter at the initial moment, the specific enthalpy parameter at the initial moment, and the specific entropy parameter at the initial moment.

[0037] Specifically, based on the temperature value and the pressure value at the initial moment, thermodynamic software, such as refprop software, can be used to determine the specific thermodynamic energy parameter at the initial moment, the specific enthalpy parameter at the initial moment, and the specific entropy parameter at the initial moment.

[0038] Optionally, determining the thermodynamic parameters at a next moment and the state data at a next moment based on the thermodynamic parameters at the initial moment and the state data at the initial moment includes: Obtaining the gas mass flow rate of the high-pressure gas storage unit 1 during the energy release process, and determining the total mass of the gas in the high-pressure gas storage unit 1 at the next moment based on the gas mass flow rate, and determining the density at the next moment based on the total mass of the gas in the high-pressure gas storage unit 1 at the next moment and the volume; According to the law of conservation of energy of unsteady flow in an open system, the specific thermodynamic energy parameters at the next moment are determined; According to the specific thermodynamic energy parameter at the next moment and the density at the next moment, the thermodynamic software is used to respectively determine the temperature value at the next moment, the pressure value at the next moment, the specific enthalpy parameter at the next moment, and the specific entropy parameter at the next moment.

[0039] Specifically, the gas mass flow rate of the high-pressure gas storage unit 1 during the energy release process is obtained. The gas mass flow rate refers to the mass of supercritical or liquid high-pressure carbon dioxide flowing out of the high-pressure gas storage unit 1 per unit time. The total mass of gas in the high-pressure gas storage unit 1 at the next moment is the total mass of high-pressure carbon dioxide remaining in the high-pressure gas storage unit 1 after a time interval. According to the gas mass flow rate and the mass conservation formula, the total mass of gas in the high-pressure gas storage unit 1 at the next moment is determined. The mass conservation formula includes: ; in, is the total mass of gas in the high-pressure gas storage unit 1 at the next moment, is the total mass of gas in the high-pressure gas storage unit 1 at the initial moment or the total mass of gas in the high-pressure gas storage unit 1 at the current moment, is the gas mass flow rate, is the time interval.

[0040] Then, based on the total mass of gas in the high-pressure gas storage unit 1 and the volume at the next moment, the density at the next moment is determined using a density formula. The density formula includes: ; Where m is the total mass of gas in the high-pressure gas storage unit 1 at the next moment, V is the volume, is the gas density at the next moment.

[0041] Then, according to the law of conservation of energy and mass of unsteady flow in an open system, the specific thermodynamic energy parameter at the next moment is determined. Then, according to the specific thermodynamic energy parameter at the next moment and the density at the next moment, the refprop software and the thermodynamic parameter formula group are used to determine the temperature value at the next moment, the pressure value at the next moment, the specific enthalpy parameter at the next moment, and the specific entropy parameter at the next moment on the physical property curve. The thermodynamic parameter formula group includes: ; in ，T The temperature value at the next moment ，P The pressure value at the next moment ，h is the specific enthalpy parameter at the next moment ，s is the specific entropy parameter at the next moment ， 、 、 are all functions in the refprop software, u is the specific thermodynamic energy parameter at the next moment, is the density at the next moment.

[0042] Optionally, determining the specific thermodynamic energy parameter at the next moment according to the law of conservation of energy of unsteady flow in an open system includes: According to the law of conservation of energy of the unsteady flow of the opening system, the specific thermodynamic energy parameter determination formula is used to determine the specific thermodynamic energy parameter at the next moment. The specific thermodynamic energy parameter determination formula includes: ; in, is the initial moment, is the time interval, For the next moment, is the specific thermodynamic energy parameter at the next moment, m is the total mass of the gas at the initial moment, is the specific thermodynamic energy parameter at the initial moment, mf is the gas mass flow rate, h is the specific enthalpy parameter, is the specific enthalpy parameter of carbon dioxide in saturated liquid state at the pressure at time t, is the total mass of gas in the high-pressure gas storage unit 1 at the next moment.

[0043] Specifically, is the specific enthalpy parameter of carbon dioxide in saturated liquid state at the pressure at time t. Because when high-pressure carbon dioxide is in gas-liquid coexistence state, the liquid carbon dioxide released at the bottom of the high-pressure gas storage unit 1 is in saturated state. In the subsequent iterative cycle calculation process, the parameters at the initial moment are replaced by the current moment, that is, in the subsequent iterative cycle calculation process, is the current moment, m is the total mass of gas in the high-pressure gas storage unit 1 at the current moment, is the specific thermodynamic energy parameter at the current moment.

[0044] Optionally, the thermodynamic change curve includes a dryness change curve, a pressure change curve inside the high-pressure gas storage unit 1, and a liquid pump pressure head change curve. Generating the thermodynamic change curve according to the thermodynamic parameters at each moment and the state data at each moment includes: generating the dryness variation curve according to the thermodynamic parameters at each moment; generating a pressure change curve inside the high-pressure gas storage unit 1 according to the state data at each moment; The liquid pump pressure head variation curve is generated according to the internal pressure variation curve of the high-pressure gas storage unit 1 and the preset outlet pressure value.

[0045] Specifically, the dryness change curve is generated using a dryness formula according to the thermodynamic parameters at each moment. The dryness formula includes: ; Where x is the dryness, is the enthalpy of gas-liquid coexistence of carbon dioxide, is the enthalpy of saturated liquid carbon dioxide, is the enthalpy of saturated gaseous carbon dioxide. In addition, the dryness can also be determined by using the refprop software, using density and specific thermodynamic energy to determine the dryness at that moment from the physical property curve.

[0046] According to the status data at each moment, that is, the pressure value at each moment, a pressure change curve inside the high-pressure gas storage unit 1 is generated. The liquid pump pressure head change curve refers to a curve showing that the pressure head of the liquid pump changes with the energy release time. The pressure head of the liquid pump is the difference between the outlet pressure and the inlet pressure of the liquid pump. The outlet pressure is a fixed value and can be set according to actual conditions. For example, the preset outlet pressure value is set to 10 MPa, and the inlet pressure is the same as the internal pressure of the high-pressure gas storage unit 1. Therefore, the liquid pump pressure head change curve can be determined by the outlet pressure and internal pressure change curves.

[0047] Optionally, the frequency conversion control of the operation of the liquid pump 2 according to the thermodynamic change curve includes: Determining the high-pressure carbon dioxide state at the outlet of the high-pressure gas storage unit 1 according to the dryness change curve; The operation of the liquid pump 2 is controlled by frequency conversion according to the high-pressure carbon dioxide state and the pressure head change curve of the liquid pump.

[0048] Specifically, the state of high-pressure carbon dioxide at the outlet of the high-pressure gas storage unit 1 is determined according to the dryness change curve, such as Figure 3 As shown, when the high-pressure carbon dioxide at the outlet of high-pressure gas storage unit 1 is in a supercritical state or a gas-liquid coexistence state, energy release can be performed. The liquid pump pressure head curve is determined based on the change in the high-pressure carbon dioxide state within high-pressure gas storage unit 1 over the energy release time. The liquid pump frequency is dynamically adjusted according to the similarity law, and the operation of liquid pump 2 is controlled by frequency conversion, thereby achieving precise control of the energy release pressure, namely the expander inlet pressure. The specific steps include determining initial conditions, calculating target state parameters, deriving a new frequency using the similarity law, and finally setting this frequency in the frequency converter. Dynamically adjusting the liquid pump frequency compensates for pressure losses within the high-pressure gas storage unit, ensuring a constant expander inlet pressure and, consequently, stable system output power. When the high-pressure carbon dioxide at the outlet of high-pressure gas storage unit 1 is in a gaseous state, the energy release operation ceases.

[0049] like Figure 7 As shown, an embodiment of the present invention provides a compressed carbon dioxide energy storage system pressure stabilization control device 700, which is applied to a compressed carbon dioxide energy storage system. The compressed carbon dioxide energy storage system includes a high-pressure gas storage unit 1 with a carbon dioxide pipeline 11 at the bottom end and a liquid pump 2 provided at the outlet of the carbon dioxide pipeline 11. The liquid pump 2 is used to control the energy release pressure of the compressed carbon dioxide energy storage system. The compressed carbon dioxide energy storage system pressure stabilization control device 700 includes: An initial module 710 is configured to obtain state data of the high-pressure gas storage unit 1 at an initial moment, and determine thermodynamic parameters at the initial moment based on the state data at the initial moment; an iterative module 720, configured to determine the thermodynamic parameters and the state data at the next moment based on the thermodynamic parameters and the state data at the initial moment, and perform iterative calculations using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and the state data at the next moment, to obtain the thermodynamic parameters and the state data at each moment; The control module 730 is used to generate a thermodynamic change curve according to the thermodynamic parameters at each moment and the state data at each moment, and to perform frequency conversion control on the operation of the liquid pump 2 according to the thermodynamic change curve.

[0050] like Figure 8As shown, an electronic device 800 provided by an embodiment of the present invention includes a memory 810 and a processor 820; the memory 810 is used to store a computer program; the processor 820 is used to implement the above-mentioned compressed carbon dioxide energy storage system pressure stabilization control method when executing the computer program.

[0051] In other words, an electronic device 800 includes a memory 810 and a processor 820 coupled to the memory 810; the memory 810 is configured to store a computer program; and the processor 820 is configured to perform the following operations when executing the computer program: Acquiring state data of the high-pressure gas storage unit 1 at an initial moment, and determining thermodynamic parameters at the initial moment based on the state data at the initial moment; determining the thermodynamic parameters and the state data at the next moment according to the thermodynamic parameters at the initial moment and the state data at the initial moment, and performing iterative calculation using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and the state data at the next moment to obtain the thermodynamic parameters and the state data at each moment; A thermodynamic change curve is generated according to the thermodynamic parameters at each moment and the state data at each moment, and the operation of the liquid pump 2 is frequency-controlled according to the thermodynamic change curve.

[0052] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the above-mentioned method for controlling pressure stabilization of a compressed carbon dioxide energy storage system is implemented.

[0053] In other words, a non-volatile computer-readable storage medium stores a computer program, which, when executed by a processor, causes the processor to perform the following operations: Acquiring state data of the high-pressure gas storage unit 1 at an initial moment, and determining thermodynamic parameters at the initial moment based on the state data at the initial moment; determining the thermodynamic parameters and the state data at the next moment according to the thermodynamic parameters at the initial moment and the state data at the initial moment, and performing iterative calculation using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and the state data at the next moment to obtain the thermodynamic parameters and the state data at each moment; A thermodynamic change curve is generated according to the thermodynamic parameters at each moment and the state data at each moment, and the operation of the liquid pump 2 is frequency-controlled according to the thermodynamic change curve.

[0054] An electronic device 800 that can serve as a server or client of the present invention will now be described, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device 800 is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device 800 can also represent various forms of mobile devices, such as personal digital assistants, cellular phones, smart phones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely examples and are not intended to limit the implementation of the present invention described and / or required herein.

[0055] Electronic device 800 includes a computing unit that can perform various appropriate actions and processes based on a computer program stored in a read-only memory (ROM) or loaded from a storage unit into a random access memory (RAM). The RAM can also store various programs and data required for device operation. The computing unit, ROM, and RAM are interconnected via a bus. An input / output (I / O) interface is also connected to the bus.

[0056] Those skilled in the art will appreciate that all or part of the processes in the above-described method embodiments can be implemented through computer program instructions and associated hardware. The program can be stored in a computer-readable storage medium, and when executed, the program can include the processes in the above-described method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM). In this application, the units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in a single location or distributed across multiple network elements. Some or all of these units can be selected based on actual needs to achieve the objectives of the embodiments of the present invention. Furthermore, the functional units in the various embodiments of the present invention can be integrated into a single processing unit, each unit can exist physically separately, or two or more units can be integrated into a single unit. These integrated units can be implemented in either hardware or software functional units.

[0057] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for controlling pressure stabilization of a compressed carbon dioxide energy storage system, characterized in that: Applicable to a compressed carbon dioxide energy storage system, the compressed carbon dioxide energy storage system comprises a high-pressure gas storage unit (1) having a carbon dioxide pipeline (11) at its bottom end and a liquid pump (2) arranged at the outlet of the carbon dioxide pipeline (11), the liquid pump (2) being used to control the energy release pressure of the compressed carbon dioxide energy storage system; The method for controlling the pressure stabilization of the compressed carbon dioxide energy storage system includes: Acquiring state data of the high-pressure gas storage unit (1) at an initial moment, and determining thermodynamic parameters at the initial moment based on the state data at the initial moment; Determining the thermodynamic parameters and the state data at the next moment according to the thermodynamic parameters at the initial moment and the state data at the initial moment, and performing iterative calculations using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and state data at the next moment, to obtain the thermodynamic parameters and the state data at each moment; A thermodynamic change curve is generated according to the thermodynamic parameters at each moment and the state data at each moment, and the operation of the liquid pump (2) is frequency-controlled according to the thermodynamic change curve.

2. The method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to claim 1, wherein: The state data at the initial moment include the volume of the high-pressure gas storage unit (1), the temperature value at the initial moment, the pressure value at the initial moment, the gas mass flow rate during the energy release process, the gas density at the initial moment, and the total gas mass at the initial moment, wherein the volume and the gas mass flow rate are fixed; The obtaining of the initial state data of the high-pressure gas storage unit (1) comprises: Obtaining the preset volume, the temperature value at the initial moment, the pressure value at the initial moment, and the gas mass flow rate; Determining the gas density at the initial moment using thermodynamic software based on the temperature value and the pressure value at the initial moment; The total mass of the gas at the initial moment is determined according to the volume and the gas density at the initial moment.

3. The method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to claim 2, wherein: The thermodynamic parameters at the initial moment include a specific thermodynamic energy parameter at the initial moment, a specific enthalpy parameter at the initial moment, and a specific entropy parameter at the initial moment; Determining the thermodynamic parameters at the initial moment according to the state data at the initial moment includes: According to the temperature value at the initial moment and the pressure value at the initial moment, the thermodynamic software is used to determine the specific thermodynamic energy parameter at the initial moment, the specific enthalpy parameter at the initial moment, and the specific entropy parameter at the initial moment.

4. The method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to claim 3, wherein: The step of determining the thermodynamic parameters at a next moment and the state data at a next moment based on the thermodynamic parameters at the initial moment and the state data at the initial moment includes: Obtaining the gas mass flow rate of the high-pressure gas storage unit (1) during the energy release process, and determining the total mass of gas in the high-pressure gas storage unit (1) at the next moment based on the gas mass flow rate, and determining the density at the next moment based on the total mass of gas in the high-pressure gas storage unit (1) at the next moment and the volume; According to the law of conservation of energy of unsteady flow in an open system, the specific thermodynamic energy parameters at the next moment are determined; According to the specific thermodynamic energy parameter at the next moment and the density at the next moment, the thermodynamic software is used to respectively determine the temperature value at the next moment, the pressure value at the next moment, the specific enthalpy parameter at the next moment, and the specific entropy parameter at the next moment.

5. The method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to claim 4, characterized in that: The method of determining the specific thermodynamic energy parameter at the next moment according to the law of conservation of energy of unsteady flow in an open system includes: According to the law of conservation of energy of the unsteady flow of the opening system, the specific thermodynamic energy parameter determination formula is used to determine the specific thermodynamic energy parameter at the next moment. The specific thermodynamic energy parameter determination formula includes: ； in, For the next moment, is the initial moment, is the time interval, is the specific thermodynamic energy parameter at the next moment, m is the total mass of the gas at the initial moment, is the specific thermodynamic energy parameter at the initial moment, mf is the gas mass flow rate, h is the specific enthalpy parameter, is the specific enthalpy parameter of carbon dioxide in saturated liquid state at the pressure at time t, is the total mass of gas in the high-pressure gas storage unit (1) at the next moment.

6. The method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to claim 1, wherein: The thermodynamic change curve includes a dryness change curve, an internal pressure change curve of the high-pressure gas storage unit (1), and a liquid pump pressure head change curve. The thermodynamic change curve is generated based on the thermodynamic parameters at each moment and the state data at each moment, including: generating the dryness variation curve according to the thermodynamic parameters at each moment; Generating a pressure change curve inside the high-pressure gas storage unit (1) based on the state data at each moment; The liquid pump pressure head variation curve is generated according to the internal pressure variation curve of the high-pressure gas storage unit (1) and a preset outlet pressure value.

7. The method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to claim 6, wherein: The variable frequency control of the operation of the liquid pump (2) according to the thermodynamic change curve comprises: Determining the high-pressure carbon dioxide state at the outlet of the high-pressure gas storage unit (1) according to the dryness variation curve; The operation of the liquid pump (2) is controlled by frequency conversion according to the high-pressure carbon dioxide state and the pressure head change curve of the liquid pump.

8. A pressure stabilizing control device for a compressed carbon dioxide energy storage system, characterized in that: The invention is applied to a compressed carbon dioxide energy storage system, wherein the compressed carbon dioxide energy storage system comprises a high-pressure gas storage unit (1) provided with a carbon dioxide pipeline (11) at the bottom end thereof, and a liquid pump (2) provided at the outlet of the carbon dioxide pipeline (11), wherein the liquid pump (2) is used to control the energy release pressure of the compressed carbon dioxide energy storage system, and the compressed carbon dioxide energy storage system pressure stabilization control device comprises: An initial module, used for acquiring state data of the high-pressure gas storage unit (1) at an initial moment, and determining thermodynamic parameters at the initial moment based on the state data at the initial moment; an iteration module, configured to determine the thermodynamic parameters and the state data at the next moment based on the thermodynamic parameters and the state data at the initial moment, and perform iterative calculations using the thermodynamic parameters and the state data at the next moment as the initial thermodynamic parameters and the state data at the next moment, to obtain the thermodynamic parameters and the state data at each moment; The control module is used to generate a thermodynamic change curve according to the thermodynamic parameters at each moment and the state data at each moment, and to frequency-control the operation of the liquid pump (2) according to the thermodynamic change curve.

9. An electronic device, characterized in that: including memory and processor; The memory is used to store computer programs; The processor is configured to implement the method for controlling the pressure stabilization of a compressed carbon dioxide energy storage system according to any one of claims 1 to 7 when executing the computer program.

10. A computer-readable storage medium, characterized in that The storage medium stores a computer program, and when the computer program is executed by the processor, the method for voltage stabilization control of a compressed carbon dioxide energy storage system according to any one of claims 1 to 7 is implemented.

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