An analytical method for performance of advanced adiabatic compressed air energy storage system

Abstract

The application relates to a performance analysis method of an advanced adiabatic compressed air energy storage system, which comprises the following steps: when the application scene is determined, the inlet pressure and temperature of a first compressor, the outlet pressure of a last compressor, the inlet pressure of a first expander and the outlet pressure of a last expander are known; the outlet temperature of the first compressor, the outlet temperature of the first expander, the pinch point temperature difference of a heat exchanger, the isentropic efficiency of each compressor and expander, the compressed mass flow, the compression time length, the expanded mass flow, the expansion time length are unknown; the outlet temperature of the last compressor, the inlet temperature of the first expander, the outlet temperature of the last expander and the polytropic efficiency of each compressor and expander are dependent variables of the known and unknown parameters; according to the relationship among the parameters, the compression power, the expansion power and the electric-to-electric efficiency are theoretically calculated, and the optimal scheme of the system performance of the advanced adiabatic compressed air energy storage is obtained in the shortest time cost and the least calculation cost.

Description

Technical Field

[0001] This invention belongs to the field of new energy and energy-saving technology, and specifically relates to a method for analyzing the performance of an advanced adiabatic compressed air energy storage system. Background Technology

[0002] The achievement of carbon neutrality is inextricably linked to long-term energy storage technology. Long-term energy storage can enhance the absorption capacity of new energy sources, provide flexibility for the power grid, and capture peak-valley arbitrage opportunities. Among long-term energy storage technologies, advanced adiabatic compressed air energy storage technology has seen rapid growth in its construction scale due to its advantages such as low pollution, low investment, and large capacity.

[0003] Existing advanced adiabatic compressed air energy storage technologies typically employ commercial software to calculate the thermal processes, selecting the optimal thermal process scheme based on a limited number of calculations. However, this method incurs significant time and computational costs, and it remains impossible to determine whether the selected thermal process scheme is truly the optimal one.

[0004] Whether it is possible to derive universal formulas from thermodynamic principles to calculate system performance, whether it is possible to calculate data such as compression power, expansion power, and electro-electric efficiency of advanced adiabatic compressed air energy storage using certain formulas and select the optimal process conditions, and whether there are methods to save time and computational costs—these questions remain unresolved. Summary of the Invention

[0005] The purpose of this invention is to provide an analytical method for the performance of an advanced adiabatic compressed air energy storage system. This method theoretically calculates the power consumption during compression, the work done during expansion, and the efficiency of the electricity-to-electricity pair, so as to obtain the optimal system performance solution for advanced adiabatic compressed air energy storage with the shortest time cost and the lowest computational cost.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for analyzing the performance of an advanced adiabatic compressed air energy storage system includes the following steps:

[0008] When the application scenario of the advanced adiabatic compressed air energy storage system is determined, the outlet temperature of the last compressor is determined based on the inlet pressure, inlet temperature, and outlet temperature of the first compressor, the outlet pressure of the last compressor, and the isentropic efficiency of each compressor; the polytropic efficiency of each compressor is determined based on the inlet temperature, outlet temperature, and isentropic efficiency of the first compressor; and the compression power of the compression stage is determined based on the inlet temperature and outlet temperature of the first compressor, the polytropic efficiency of each compressor, and the mass flow rate of the compression stage.

[0009] The inlet temperature of the first expander is determined based on the outlet temperature of the first compressor and the pinch temperature difference of the heat exchanger. The outlet temperature of the last expander is determined based on the inlet pressure, inlet temperature, and outlet temperature of the first expander, the outlet pressure of the last expander, and the isentropic efficiency of each expander. The polytropic efficiency of each expander is determined based on the inlet temperature, outlet temperature, and isentropic efficiency of the first expander. The expansion power of the expansion stage is determined based on the inlet temperature and outlet temperature of the first expander, the polytropic efficiency of each expander, and the mass flow rate of the expansion stage.

[0010] The electrical-to-electrical efficiency of an advanced adiabatic compressed air energy storage system is determined based on compression power, compression duration, expansion power, and expansion duration.

[0011] A further improvement of the present invention is that the outlet temperature of the final compressor is:

[0012]

[0013] Where, p 1C,in p is the inlet pressure of the first compressor. aC,out T is the outlet pressure of the last compressor. 1C,in T is the inlet temperature of the first compressor. 1C,out η is the outlet temperature of the first compressor. s,xC For any compressor, η is the isentropic efficiency. s,aC Let be the isentropic efficiency of the last compressor, and 'a' be the total number of compressors.

[0014] A further improvement of this invention is that the variable efficiency of each compressor is:

[0015]

[0016] Among them, T xC,out Let T be the outlet temperature of any compressor, and let T be the outlet temperature of all compressors except the last compressor. xC,out =T 1C,out .

[0017] A further improvement of the present invention is that the compression power during the compression stage is:

[0018]

[0019] in, R is the mass flow rate during the compression stage, κ is the air adiabatic index, and R is the mass flow rate during the compression stage. g is the gas constant.

[0020] A further improvement of the present invention is that the inlet temperature of each expander is:

[0021] T 1EX,in =T 1C,out-2ΔT

[0022] Where T 1EX,in T is the inlet temperature of the first expander. 1C,out ΔT is the outlet temperature of the first compressor, and ΔT is the pinch temperature difference of the heat exchanger.

[0023] A further improvement of the present invention is that the outlet temperature of the final expander is:

[0024]

[0025] Where, p 1EX,in p is the inlet pressure of the first expander. bEX,out T is the outlet pressure of the final expander. 1EX,out η is the outlet temperature of the first expander. s,yEX Let η be the isentropic efficiency of any expander. s,bEX Let b be the isentropic efficiency of the final expander, and b be the total number of expanders.

[0026] A further improvement of the present invention is that the variable efficiency of each expander is:

[0027]

[0028] Among them, T yEX,out Let be the outlet temperature of any expander.

[0029] A further improvement of the present invention is that the expansion power during the expansion stage is:

[0030]

[0031] in, This refers to the mass flow rate during the expansion phase.

[0032] A further improvement of this invention lies in the electrical-to-electrical efficiency of the advanced adiabatic compressed air energy storage system:

[0033]

[0034] Among them, h C To compress the duration, h EX This is the duration of the expansion.

[0035] A further improvement of this invention is that the mass flow rate during the compression phase, the mass flow rate during the expansion phase, the compression duration, and the expansion duration all exhibit a mass conservation relationship:

[0036]

[0037] in, It is the mass flow rate offset coefficient that exists due to the influence of humid air.

[0038] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0039] (1) This invention proposes an analytical algorithm for the power and efficiency of an advanced adiabatic compressed air energy storage system, which is derived based on the fundamental thermodynamic theorem and has universality and accuracy.

[0040] (2) The power and efficiency analytical algorithm has fewer variables, which can save time and computational resources and improve computational efficiency.

[0041] (3) Taking into account the actual situation of equipment manufacturers, the relationship between isentropic efficiency and polytropic efficiency of compressors and expanders is derived, making the application scope of this analytical algorithm wider.

[0042] (4) By analyzing the calculation results of this analytical algorithm, the optimal process configuration of the advanced adiabatic compressed air energy storage system under specific application scenarios can be quickly obtained. Attached Figure Description

[0043] Figure 1 This is a flowchart of an advanced insulated compressed air energy storage system.

[0044] The symbols in the diagram represent the following: 1-First compressor, 2-Second compressor, 3-Final compressor, 4-Gas storage device, 5-First expander, 6-Second expander, 7-Final expander, 8-First high-quality heat cooler, 9-Second high-quality heat cooler, 10-Third high-quality heat cooler, 11-First high-quality heat heater, 12-Second high-quality heat heater, 13-Third high-quality heat heater, 14-First water cooler, 15-Second water cooler, 16-Third water cooler, 17-First water heater, 18-Fourth water cooler, 19-High-quality high-temperature storage tank, 20-High-quality low-temperature storage tank, 21-High-temperature water storage tank, 22-Low-temperature water storage tank, 23-First gas-liquid separator, 24-Second gas-liquid separator, 25-Third gas-liquid separator.

[0045] Figure 2 This is a schematic diagram of the compression power for implementing Case 1.

[0046] Figure 3 This is a schematic diagram of the expansion power for implementing Case 1.

[0047] Figure 4 This is a schematic diagram illustrating the electricity-to-electricity efficiency of Case Study 1.

[0048] Figure 5 A schematic diagram of the compression power for implementing Case 2.

[0049] Figure 6 This is a schematic diagram of the expansion power for implementing Case 2.

[0050] Figure 7 A schematic diagram illustrating the electricity-to-electricity efficiency of Case 2. Detailed Implementation

[0051] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0052] This invention, based on the first and second laws of thermodynamics, provides a thermodynamic derivation of an advanced adiabatic compressed air energy storage system. Since the storage device in an advanced adiabatic compressed air energy storage system can be a salt cavern, artificial chamber, etc., its pressure-bearing capacity is limited by the inherent performance of the storage device. Therefore, the outlet pressure of the final compressor in the compression stage should match the pressure-bearing capacity of the energy storage device; that is, the outlet pressure of the final compressor is a known value.

[0053] To facilitate the derivation of thermodynamic processes, the following assumptions are made:

[0054] (1) The working medium, air, is an ideal gas that satisfies the ideal gas law pv = R g T;

[0055] (2) The heat exchangers, separators, pipelines, gas storage devices, etc. in the system have no pressure loss, and the power consumption of the oil pumps, water pumps, etc. in the system is ignored.

[0056] (3) During the compression stage, the mass flow rate of the air remains constant. If the inlet air is humid air, the humid air mass flow rate is used when calculating the compression power, the mass flow rate offset coefficient is introduced when calculating the mass conservation, and the dry air mass flow rate is used when calculating the expansion power.

[0057] (4) During the compression stage, the inlet temperature and pressure of the first compressor are the ambient temperature and pressure, which are known values;

[0058] (5) During the compression stage, due to the influence of the compressor precooler, the air temperature at the inlet of each compressor is the same, which is the air inlet temperature.

[0059] (6) During the compression stage, the outlet temperature of all compressors except the last compressor is set to be the same, which is a variable in the performance calculation process;

[0060] (7) During the expansion stage, the inlet pressure of the first expander is the same as the outlet pressure of the last compressor.

[0061] (8) During the expansion stage, the inlet temperature of each expander is the same due to the performance of the heater in front of the expander.

[0062] (9) During the expansion stage, it is assumed that the outlet temperature of all expanders except the last expander is the same, which is a variable in the calculation process;

[0063] (10) During the expansion stage, the outlet pressure of the last expander is the ambient pressure, which is a known value;

[0064] (11) The pinch temperature difference between hot and cold fluids is the same in all heat exchangers (coolers for compression and heaters for expansion) in the system.

[0065] In addition to the above assumptions, it should be noted that:

[0066] ①According to the ideal gas polymorphic process equation, we have For any compressor or expander, when the inlet gas state is known, the outlet gas state p out T out They are mutually dependent variables, meaning that when one is constant, the other is also constant. All formulas in this invention use temperature as the main variable.

[0067] ②Since the outlet pressure of the last compressor is known, the outlet temperature of the last compressor is a dependent variable of the outlet pressure, not an unknown value.

[0068] ③Since the outlet pressure of the final expander is known, the outlet temperature of the final expander is a dependent variable of the outlet pressure, not an unknown value.

[0069] ④ Since the heat storage medium is used in both the compression and expansion stages, the inlet temperature of the expander is a dependent variable of the compressor outlet temperature and the temperature difference between the heat exchanger pinch points, influenced by the heat storage medium.

[0070] 1) Performance Analysis Formula for Advanced Adiabatic Compressed Air Energy Storage System Based on Variable Efficiency of Compressor and Expander

[0071] Based on the above assumptions, and in conjunction with the first and second laws of thermodynamics, the formulas for calculating the compression power, expansion power, and electro-pair efficiency of an advanced adiabatic compressed air energy storage system containing an arbitrary number of compressors and expanders are as follows:

[0072]

[0073]

[0074]

[0075] In equations (1)-(3), there are some mutually constrained variables, as follows:

[0076] If mass is conserved during the compression and expansion phases, then... in It is the mass flow rate offset coefficient that exists due to the influence of humid air.

[0077] Due to the heat transfer effect of the heat storage medium, T 1EX,in =T 1C,out -2ΔT, where ΔT is the temperature difference at the heat exchanger pinch point.

[0078] Based on equation (1), the compression power can be calculated by specifying the air mass flow rate of the compression stage, the inlet and outlet temperatures of the first compressor, the inlet pressure of the first compressor and the outlet pressure of the last compressor, and the polytropic efficiency of each compressor.

[0079] Based on equation (2), the expansion power can be calculated by specifying the air mass flow rate of the expansion stage, the inlet and outlet temperatures of the first expander, the inlet pressure of the first expander and the outlet pressure of the last expander, and the polytropic efficiency of each expander.

[0080] Based on equation (3), the electrical efficiency of the advanced adiabatic compressed air energy storage system can be calculated by specifying the compression and expansion durations.

[0081] For advanced adiabatic compressed air energy storage systems with defined application scenarios, the ambient temperature, ambient pressure, and pressure of the storage device are all known. Therefore, the inlet temperature and inlet pressure of the first compressor, and the outlet pressure of the last compressor are known. Only the air mass flow rate during the compression stage, the outlet temperature of the first compressor, and the polytropic efficiency of each compressor need to be specified to calculate the power of the compression process.

[0082] Accordingly, the inlet pressure of the first expander and the outlet pressure of the last expander in the expansion stage are known parameters. After determining the compression and expansion durations, the air mass flow rate in the expansion stage can be determined. After specifying the pinch temperature difference of the heat exchangers, the inlet temperature of the first expander can be determined. Therefore, by specifying the outlet temperature of the first expander in the expansion stage and the polytropic efficiency of each expander, the expansion power can be calculated.

[0083] The electrical-to-electrical efficiency of an advanced adiabatic compressed air energy storage system can be calculated using parameters such as compression power, compression duration, expansion power, and expansion duration, along with calculation results.

[0084] 2) Relationship between isentropic efficiency and polytropic efficiency of compressors and expanders

[0085] In engineering applications, some equipment manufacturers only provide the isentropic efficiency of their equipment, not its variable efficiency. To address the impact of this situation on the performance calculation failure of advanced adiabatic compressed air energy storage systems, it is necessary to establish the relationship between isentropic efficiency and variable efficiency.

[0086] For any compressor, the relationship between the compressor's isentropic efficiency and polytropic efficiency is as follows:

[0087]

[0088] The inlet temperature of all compressors is known. Except for the last compressor, the outlet temperature of the remaining compressors is a variable that can affect the compression power.

[0089] The outlet temperature of the final compressor is the dependent variable of the outlet pressure, which can be expressed as:

[0090]

[0091] By converting the isentropic efficiency of each compressor into the polytropic efficiency using equations (4) and (5), the compression power can be calculated using equation (1). No new calculation variables were introduced during the calculation process.

[0092] For any expander, the relationship between the isentropic efficiency and the polytropic efficiency is as follows:

[0093]

[0094] The inlet temperature of all expanders is a dependent variable of the compressor outlet temperature and the temperature difference at the heat exchanger pinch point. Except for the last expander, the outlet temperature of the other expanders is a variable that can affect the expansion power.

[0095] The outlet temperature of the final expander is a dependent variable of the outlet pressure, which can be expressed as:

[0096]

[0097] By converting the isentropic efficiency of each expander into the polytropic efficiency using equations (6) and (7), the expansion power can be calculated using equation (2). No new calculation variables were introduced during the calculation process.

[0098] After calculating the compression power and expansion power separately, the electrical-to-electrical efficiency of the advanced adiabatic compressed air energy storage system can be calculated based on the compression duration and expansion duration.

[0099] The meanings of the symbols in equations (1)-(7) are as follows:

[0100]

[0101]

[0102] Example

[0103] like Figure 1 As shown, the present invention takes an advanced adiabatic compressed air energy storage system consisting of three compressors, three expanders, and multiple heat exchangers as a specific embodiment.

[0104] During the compression stage, ambient air is compressed into high-temperature, high-pressure gas by three compressors. To recover high-temperature heat energy, the gas exiting the compressors exchanges heat with a high-quality heat transfer medium in a high-quality thermal cooler, and then enters a water cooler for further cooling, ensuring that the inlet temperature of all three compressors is the same as the ambient temperature. Considering that the inlet air may be humid, a separator is installed in the process. During the compression process, the air undergoes three compressions and multiple coolings before entering the gas storage device.

[0105] The high-quality heat medium is stored in a high-quality heat storage tank after heat exchange, and is used to heat high-pressure air during the expansion stage.

[0106] During the expansion phase, high-pressure, room-temperature air is drawn from the storage device, preheated by a water heater, and then flows into a high-quality heat heater where it is heated by a high-temperature, high-quality heat medium into a high-temperature, high-pressure gas. It then flows into the expander to expand and perform work. During the expansion phase, the air undergoes multiple heating cycles and three expansions. The outlet pressure of the third expander is ambient pressure. The air then flows into a water cooler, where it is cooled to ambient temperature and pressure and discharged into the atmosphere.

[0107] In the calculations of this embodiment, the following assumptions are made:

[0108] (1) The working medium, air, is an ideal gas.

[0109] (2) The heat exchangers, separators, pipelines, gas storage devices, etc. in the system have no pressure loss, and the power consumption of the oil pumps, water pumps, etc. in the system is ignored.

[0110] (3) During the compression phase, the mass flow rate of air remains constant;

[0111] (4) The ambient temperature is 20℃ and the ambient pressure is 101.325kPa.

[0112] (5) During the compression stage, due to the influence of the compressor precooler, the inlet temperature of each compressor is the ambient temperature, i.e., T. 1C,in =T 2C,in =T 3C,in =20℃;

[0113] (6) During the compression stage, the inlet pressure of the first compressor is the same as the ambient pressure, i.e., p 1C,in =101.325 kPa, the outlet pressure of the last compressor is p 3C,out =20MPa;

[0114] (7) During the expansion stage, the inlet pressure of the first expander is p 1EX,in =20MPa;

[0115] (8) During the expansion stage, due to the performance of the heaters before the expanders, the inlet temperature of each expander is the same, i.e., T. 1EX,in =T 2EX,in =T 3EX,in ;

[0116] (9) During the expansion stage, the outlet temperatures of the first and second expanders are the same, i.e., T 1EX,out T 2EX,out ;

[0117] (10) During the expansion stage, the outlet pressure of the final expander is the ambient pressure, p 3EX,out =101.325 kPa;

[0118] (11) The pinch temperature difference between the hot and cold fluids in all heat exchangers in the system is the same, ΔT = 10℃;

[0119] (12) The upper limit of the temperature of the high-quality heat transfer medium is 340℃, and the lower limit is 80℃;

[0120] (13) Compression time: 8 hours; expansion time: 5 hours.

[0121] Implementation Case 1:

[0122] In addition to the basic assumptions mentioned above, this case also includes the following assumptions:

[0123] (1) The inlet of the first compressor is dry air;

[0124] (2) The polytropic efficiency of the three compressors and the three expanders is 85.15%.

[0125] According to equations (1)-(3), the formulas used to calculate compression power, expansion power, and electric couple efficiency in this example can be written as follows:

[0126]

[0127]

[0128]

[0129] Because the inlet medium is dry air, the mass flow rate offset coefficient...

[0130] When the compressor outlet temperature ranges from [230℃ to 380℃] and the expander outlet temperature ranges from [80℃ to 220℃], the changes in compression power, expansion power, and electro-pair efficiency are shown below. Figures 2-4 .

[0131] Depend on Figure 2 From equation (8), we can see that the compression power is T. 1C,out A single-valued function, has a T 1C,out This value minimizes the compression power. On both sides of the minimum value, the compressor outlet temperature T... 1C,out As the value moves away from its minimum, the compression power increases. At T... 1C,out At the upper boundary of 380°C, the compression power is at its maximum value.

[0132] like Figure 3 As shown, the expansion power is simultaneously affected by T 1EX,out T 1EX,in The combined effects of these factors. Because the temperature difference between the high-quality heat cooler pinch points during compression is 10℃, the heat storage temperature of the high-quality heat medium and the compressor outlet temperature T... 1C,out There will always be a difference. Since the upper temperature limit for high-quality heat transfer media is 340℃, when the compressor outlet temperature T... 1C,out Above 350℃, the heat storage temperature of the high-quality heat transfer medium remains at 340℃. Therefore, during the expansion stage, the upper limit of the expander inlet temperature is 330℃. When the expander inlet temperature is at the upper limit of 330℃, as the expander outlet temperature T... 1EX,out Within the temperature range of [80℃, 220℃], there exists a working point that maximizes the expansion power. Specific information includes: expander inlet temperature T. 1EX,in =330℃, expander outlet temperature T 1EX,out =120℃, the expander power is 305.72MW.

[0133] When the compressor outlet temperature T 1C,out When the temperature varies between [350℃, 380℃], the compression power increases with increasing outlet temperature. However, when the compressor outlet temperature T... 1C,out When the temperature varies from [350℃, 380℃], the expander inlet temperature T 1EX With in constant, the expander power increases with the expander outlet temperature T. 1EX,out And changes. Therefore, the compressor outlet temperature T is selected. 1C,out and expander outlet temperature T 1EX,out The description of the changes in the electro-pair efficiency is presented in [the table / document]. Figure 4 When the compressor outlet temperature T 1C,out At [230℃, 380℃], the expander outlet temperature T 1EX,out Within the range of [80℃, 220℃], there exists an operating point that optimizes the efficiency of the electro-pair circuit. Specific information includes: compressor outlet temperature T. 1C,out =350℃, expander outlet temperature T 1EX,out =120℃, the electro-electric efficiency is 83.11%.

[0134] according to It can be calculated that when the electrical-to-electric efficiency is optimal, the outlet pressure of the first compressor is 958.86 kPa, the outlet pressure of the second compressor is 9.07 MPa, the outlet pressure of the first expander is 3.44 MPa, and the outlet pressure of the second expander is 593 kPa.

[0135] When the electro-electric efficiency is optimal, the detailed thermal process is as follows: Dry air flows into the first compressor at 20°C and 101.325 kPa, with a mass flow rate of 1,140,000 kg / h. The outlet temperature of the first compressor is 350°C and 958.86 kPa. After heat exchange in the cooler, it flows into the second compressor at 20°C and 958.86 kPa, with an outlet temperature of 350°C and 9.07 MPa. After heat exchange in the cooler, it flows into the final compressor at 20°C and 9.07 MPa, with an outlet pressure of 20 MPa. After further heat exchange in the cooler, it enters the gas storage device at 20°C and 20 MPa. When power generation is required, ambient temperature high-pressure air flows out from the gas storage device, is heated by the heater, and flows into the first expander at 330℃ and 20MPa, with a mass flow rate of 1,824,000 kg / h. The outlet temperature of the first expander is 120℃ and 3.44MPa. Heated to 330℃ and 3.44MPa in the heater, it flows into the second expander, exiting at 120℃ and 593kPa. Heated to 330℃ and 593kPa in the heater, it flows into the final expander, expanding to 101.325kPa before exiting. The total compression power is 229.90MW, the expansion power is 305.72MW, and the electricity-to-electricity efficiency is 83.11%.

[0136] Implementation Case 2:

[0137] In addition to the basic assumptions mentioned above, this case also includes the following assumptions:

[0138] (1) The inlet of the first compressor is humid air with a relative humidity of 0.87;

[0139] (2) The isentropic efficiency of the three compressors is 80%, and the isentropic efficiency of the three expanders is 85.6%.

[0140] Based on fundamental thermodynamic principles, the mass flow rate offset coefficient of moist air Where d represents the moisture content of the humid air.

[0141] Since the known data in this example are the isentropic efficiencies of the compressor and expander, in order to calculate the compression power, expansion power, and electro-pair efficiency, it is first necessary to convert the isentropic efficiencies into polytropic efficiencies. According to equation (4), the polytropic efficiencies of the first compressor, the second compressor, and the last compressor are calculated as follows:

[0142]

[0143]

[0144]

[0145] According to equation (5), T in equation (13) 3C,out The calculation method is as follows:

[0146]

[0147] According to equation (6), the polytropic efficiency calculation formulas for the first, second, and third expanders are as follows:

[0148]

[0149]

[0150]

[0151] According to equation (7), T in equation (17) 3EX,out The calculation method is as follows:

[0152]

[0153] Substituting equations (11)-(13) and (15)-(17) into equations (8)-(10), when the compressor outlet temperature range is [230℃, 380℃] and the expander outlet temperature range is [80℃, 220℃], the changes in compression power, expansion power, and electro-pair efficiency are shown in the figure. Figures 5-7 .

[0154] In this case, the compression power is T. 1C,out A single-valued function, has a T 1C,out This value minimizes the compression power. On both sides of the minimum value, the compressor outlet temperature T... 1C,out As the value moves away from its minimum, the compression power increases. At T... 1C,out At the upper boundary of 380°C, the compression power is at its maximum value, such as... Figure 5 As shown.

[0155] like Figure 6 As shown, the expansion power is simultaneously affected by T 1EX,out T 1EX,in The combined effects of these factors. Because the temperature difference between the high-quality heat cooler pinch points during compression is 10℃, the heat storage temperature of the high-quality heat medium and the compressor outlet temperature T... 1C,out There will always be a difference. Since the upper temperature limit for high-quality heat transfer media is 340℃, when the compressor outlet temperature T...1C,out Above 350℃, the heat storage temperature of the high-quality heat transfer medium remains at 340℃. Therefore, during the expansion stage, the upper limit of the expander inlet temperature is 330℃. When the expander inlet temperature is at the upper limit of 330℃, as the expander outlet temperature T... 1EX,out Within the temperature range of [80℃, 220℃], there exists a working point that maximizes the expansion power. Specific information includes: expander inlet temperature T. 1EX,in =330℃, expander outlet temperature T 1EX,out =125℃, the expander power is 300.83MW.

[0156] When the compressor outlet temperature T 1C,out When the temperature varies between [350℃, 380℃], the compression power increases with increasing outlet temperature. However, when the compressor outlet temperature T... 1C,out When the temperature varies from [350℃, 380℃], the expander inlet temperature T 1EX,in The expander power remains constant, but the expander outlet temperature T changes with the expander outlet temperature. 1EX,out And changes. Therefore, the compressor outlet temperature T is selected. 1C,out and expander outlet temperature T 1EX,out The description of the changes in the electro-pair efficiency is presented in [the table / document]. Figure 7 When the compressor outlet temperature T 1C,out At [230℃, 380℃], the expander outlet temperature T 1EX,out Within the range of [80℃, 220℃], there exists an operating point that optimizes the efficiency of the electro-pair circuit. Specific information includes: compressor outlet temperature T. 1C,out =350℃, expander outlet temperature T 1EX,out =125℃, the electric field efficiency is 81.37%.

[0157] according to It can be calculated that when the electrical-to-electric efficiency is optimal, the outlet pressure of the first compressor is 958.97 kPa, the outlet pressure of the second compressor is 9.08 MPa, the outlet pressure of the first expander is 3.40 MPa, and the outlet pressure of the second expander is 579.37 kPa.

[0158] When the electro-electric efficiency is optimal, the detailed thermal process is as follows: Air flows into the first compressor at 20°C, 101.325 kPa, and 0.87 relative humidity, with a mass flow rate of 1,140,000 kg / h. The outlet temperature of the first compressor is 350°C and 958.97 kPa. After heat exchange in the cooler, it flows into the second compressor at 20°C and 958.97 kPa, with an outlet temperature of 350°C and 9.08 MPa. After heat exchange in the cooler, it flows into the final compressor at 20°C and 9.08 MPa, with an outlet pressure of 20 MPa. After further heat exchange in the cooler, it enters the gas storage device at 20°C and 20 MPa. When power generation is required, ambient temperature high-pressure air flows out from the gas storage device, is heated by the heater, and flows into the first expander at 330℃ and 20MPa, with a mass flow rate of 1800272 kg / h. The outlet temperature of the first expander is 125℃ and 3.40MPa. Heated to 330℃ and 3.40MPa in the heater, it flows into the second expander, exiting at 125℃ and 579.37kPa. Heated to 330℃ and 579.37kPa in the heater, it flows into the final expander, expanding to 101.325kPa before exiting. The total compression power is 231.06MW, the expansion power is 300.83MW, and the electricity-to-electric efficiency is 81.37%.

[0159] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for analyzing the performance of an advanced adiabatic compressed air energy storage system, characterized in that, Includes the following steps: When the application scenario of the advanced adiabatic compressed air energy storage system is determined, the outlet temperature of the last compressor is determined based on the inlet pressure, inlet temperature and outlet temperature of the first compressor, the outlet pressure of the last compressor and the isentropic efficiency of each compressor. The polytropic efficiency of each compressor is determined based on the inlet temperature, outlet temperature, and isentropic efficiency of the first compressor. The compression power of the compression stage is determined based on the inlet and outlet temperatures of the first compressor, the polytropic efficiency of each compressor, and the mass flow rate during the compression stage. The inlet temperature of the first expander is determined based on the outlet temperature of the first compressor and the pinch temperature difference of the heat exchanger. The outlet temperature of the last expander is determined based on the inlet pressure, inlet temperature, and outlet temperature of the first expander, the outlet pressure of the last expander, and the isentropic efficiency of each expander. The polytropic efficiency of each expander is determined based on the inlet temperature, outlet temperature, and isentropic efficiency of the first expander. The expansion power of the expansion stage is determined based on the inlet temperature and outlet temperature of the first expander, the polytropic efficiency of each expander, and the mass flow rate of the expansion stage. The electrical-to-electrical efficiency of an advanced adiabatic compressed air energy storage system is determined based on compression power, compression duration, expansion power, and expansion duration.

2. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 1, characterized in that, The outlet temperature of the last compressor is: Where, p 1C,in p is the inlet pressure of the first compressor. aC,out T is the outlet pressure of the last compressor. 1C,in T is the inlet temperature of the first compressor. 1C,out η is the outlet temperature of the first compressor. s,xC For any compressor, η is the isentropic efficiency. s,aC Let be the isentropic efficiency of the last compressor, and 'a' be the total number of compressors.

3. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 2, characterized in that, The variable efficiency of each compressor is: Among them, T xC,out Let T be the outlet temperature of any compressor, and let T be the outlet temperature of all compressors except the last compressor. xC,out =T 1C,out .

4. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 3, characterized in that, The compression power during the compression stage is: in, R is the mass flow rate during the compression stage, κ is the air adiabatic index, and R is the mass flow rate during the compression stage. g is the gas constant.

5. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 4, characterized in that, The inlet temperature of each expander is: T 1EX,in =T 1C,out -2ΔT Where T 1EX,in T is the inlet temperature of the first expander. 1C,out ΔT is the outlet temperature of the first compressor, and ΔT is the pinch temperature difference of the heat exchanger.

6. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 5, characterized in that, The outlet temperature of the final expander is: Where, p 1EX,in p is the inlet pressure of the first expander. bEX,out T is the outlet pressure of the final expander. 1EX,out η is the outlet temperature of the first expander. s,yEX Let η be the isentropic efficiency of any expander. s,bEX Let b be the isentropic efficiency of the final expander, and b be the total number of expanders.

7. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 6, characterized in that, The variable efficiency of each expander is: Among them, T yEX,out Let be the outlet temperature of any expander.

8. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 7, characterized in that, The expansion power during the expansion phase is: in, This refers to the mass flow rate during the expansion phase.

9. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 8, characterized in that, The electrical efficiency of the advanced adiabatic compressed air energy storage system: Among them, h C To compress the duration, h EX This is the duration of the expansion.

10. The method for analyzing the performance of an advanced adiabatic compressed air energy storage system according to claim 9, characterized in that, There is a mass conservation relationship between the mass flow rate during compression, the mass flow rate during expansion, the compression duration, and the expansion duration. in, It is the mass flow rate offset coefficient that exists due to the influence of humid air.

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