CN117172155A - Analysis method for performance of advanced adiabatic compressed air energy storage system - Google Patents
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Abstract
The invention discloses an analysis method for the performance of an advanced adiabatic compressed air energy storage system, which comprises the following steps: when the application scenario is determined, the inlet pressure and temperature of the first compressor, the outlet pressure of the last compressor, the inlet pressure of the first expander, and the outlet pressure of the last expander are all known. The outlet temperature of the first compressor, the outlet temperature of the first expander, the pinch temperature difference of the heat exchanger, the isentropic efficiency of each compressor and expander, the compression stage mass flow, the compression time period, the expansion stage mass flow and the expansion time period are unknown. The last compressor outlet temperature, the first expander inlet temperature, the last expander outlet temperature, the polytropic efficiency of each compressor and expander are dependent variables of the known and unknown quantities. According to the relation of the parameters, the invention carries out theoretical calculation on the compression power, the expansion power and the electric-to-electric efficiency, and obtains the optimal scheme of the system performance of the advanced adiabatic compressed air energy storage with the shortest time cost and the least calculation cost.
Description
Technical Field
The invention belongs to the technical field of new energy and energy conservation, and particularly relates to an analysis method for the performance of an advanced adiabatic compressed air energy storage system.
Background
The realization of the carbon neutralization target is indispensible from long-term energy storage technology. The long-term energy storage can improve new energy consumption capacity, provide flexibility for a power grid and acquire peak valley arbitrage spaces. In the long-term energy storage technology, the advanced adiabatic compressed air energy storage technology has the advantages of low pollution, low investment, large capacity and the like, and the construction scale is rapidly increased.
The thermodynamic flow of the existing advanced adiabatic compressed air energy storage technology is usually calculated by adopting commercial software, and a thermodynamic flow scheme with better system performance is screened out through limited calculation results. However, this calculation method consumes significant time and calculation costs, and it is not yet possible to determine whether the selected thermal flow scheme is the optimal scheme.
Whether the system performance can be calculated by deducing a general formula through a thermodynamic principle, whether the data such as compression power, expansion power, electric-to-electric efficiency and the like of advanced adiabatic compressed air energy storage can be calculated by certain formulas, and the optimal flow working condition is screened, and whether the method can save time cost and calculation cost is available, so the problems are not solved.
Disclosure of Invention
The invention aims to provide an analysis method for the performance of an advanced adiabatic compressed air energy storage system, which is used for carrying out theoretical calculation on the power consumption, the work in the expansion process and the electric-to-electric efficiency in the compression process, and obtaining a system performance optimal scheme of the advanced adiabatic compressed air energy storage system with the shortest time cost and the least calculation cost.
In order to achieve the above purpose, the invention adopts the following technical scheme:
an analytical method for the performance of an advanced adiabatic compressed air energy storage system, comprising the following steps:
when the application scene of the advanced adiabatic compressed air energy storage system is determined, determining the outlet temperature of the last compressor according to the inlet pressure, the inlet temperature and the outlet temperature of the first compressor, the outlet pressure of the last compressor and the isentropic efficiency of each compressor; determining the polytropic efficiency of each compressor according to the inlet temperature, the outlet temperature and the isentropic efficiency of the first compressor; determining the compression power of the compression stage according to the inlet temperature and the outlet temperature of the first compressor, the polytropic efficiency of each compressor and the mass flow of the compression stage;
determining the inlet temperature of the first expander according to the outlet temperature of the first compressor and the temperature difference of the clamping points of the heat exchanger; determining the outlet temperature of the last expander according to the inlet pressure, the inlet temperature and the outlet temperature of the first expander, the outlet pressure of the last expander and the isentropic efficiency of each expander; determining the polytropic efficiency of each expander according to the inlet temperature, the outlet temperature and the isentropic efficiency of the first expander; determining expansion power of an expansion stage according to inlet temperature and outlet temperature of the first expander, polytropic efficiency of each expander and mass flow of the expansion stage;
the electrical to electrical efficiency of the advanced adiabatic compressed air energy storage system is determined based on the compression power, the compression duration, the expansion power, and the expansion duration.
The invention is further improved in that the outlet temperature of the last compressor is:
wherein p is 1C,in For the inlet pressure, p, of the first compressor aC,out T is the outlet pressure of the last compressor 1C,in For the inlet temperature of the first compressor, T 1C,out For the outlet temperature, η of the first compressor s,xC Isentropic efficiency, η, of any compressor s,aC For isentropic efficiency of the last compressor, a is the total number of compressors.
The invention further improves that the multiple transformation efficiency of each compressor is as follows:
wherein T is xC,out Outlet temperature T of any compressor except the last compressor xC,out ＝T 1C,out 。
The invention is further improved in that the compression power of the compression stage is as follows:
wherein,for mass flow in compression stage, κ is air insulation index, R g Is a gas constant.
The invention is further improved in that the inlet temperature of each expansion machine is as follows:
T 1EX,in ＝T 1C,out -2ΔT
wherein T is 1EX,in For the inlet temperature of the first expander, T 1C,out The outlet temperature of the first compressor, deltaT, is the pinch temperature difference of the heat exchanger.
The invention is further improved in that the outlet temperature of the last expander is:
wherein p is 1EX,in For the inlet pressure, p, of the first expander bEX,out T is the outlet pressure of the final expander 1EX,out For the outlet temperature, η of the first expander s,yEX Isentropic efficiency, η, of any expander s,bEX Isentropic efficiency for the last expander, b is the total number of expanders.
The invention further improves that the polytropic efficiency of each expansion machine is as follows:
wherein T is yEX,out Is the outlet temperature of either expander.
The invention is further improved in that the expansion power of the expansion stage is:
wherein,is the mass flow rate in the expansion stage.
The invention is further improved in that the electrical to electrical efficiency of the advanced adiabatic compressed air energy storage system:
wherein h is C For the duration of compression, h EX Is the expansion duration.
The invention is further improved in that mass conservation relation exists among mass flow in the compression stage, mass flow in the expansion stage, compression time length and expansion time length:
wherein,is the mass flow offset coefficient that exists under the influence of humid air.
Compared with the prior art, the invention has at least the following beneficial technical effects:
(1) The invention provides an analysis algorithm of power and efficiency of an advanced adiabatic compressed air energy storage system, which is derived based on thermodynamic basic theorem and has universality and accuracy.
(2) The power and efficiency analysis algorithm has few variables, can save time cost and calculation resource cost, and improves calculation efficiency.
(3) The practical situation of equipment manufacturers is comprehensively considered, the relationship between isentropic efficiency and polytropic efficiency of the compressor and the expander is deduced, and the application range of the analytical algorithm is wider.
(4) By analyzing the calculation result of the analysis algorithm, the optimal flow configuration condition of the performance of the advanced adiabatic compressed air energy storage system in a specific application scene can be rapidly obtained.
Drawings
FIG. 1 is a flow chart of an advanced adiabatic compressed air energy storage system.
The meaning of each symbol in the figure is: the system comprises a first compressor, a second compressor, a 3-last compressor, a 4-gas storage device, a 5-first expansion machine, a 6-second expansion machine, a 7-last expansion machine, an 8-first high-quality heat cooler, a 9-second high-quality heat cooler, a 10-third high-quality heat cooler, an 11 first high-quality heat heater, a 12-second high-quality heat heater, a 13-third high-quality heat heater, a 14-first water cooler, a 15-second water cooler, a 16-third water cooler, a 17-first water heater, an 18-fourth water cooler, a 19-high-quality heat high-temperature storage tank, a 20-high-quality heat low-temperature storage tank, a 21-high-temperature water storage tank, a 22 low-temperature water storage tank, a 23-first gas-liquid separator, a 24-second gas-liquid separator and a 25-third gas-liquid separator.
Fig. 2 is a schematic diagram of compression power according to a first embodiment.
Fig. 3 is a schematic diagram of the expansion power of the first embodiment.
Fig. 4 is a schematic diagram of the electrical to electrical efficiency of the first embodiment.
Fig. 5 is a schematic diagram of compression power in the second embodiment.
Fig. 6 is a schematic diagram of the expansion power of the second embodiment.
Fig. 7 is a schematic diagram of the electrical to electrical efficiency of the second embodiment.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below 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 embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other. The invention will be described in detail below with reference to the drawings in connection with embodiments.
The invention is based on the first law of thermodynamics and the second law of thermodynamics, and carries out thermodynamic deduction on an advanced adiabatic compressed air energy storage system. Because the gas storage device of the advanced adiabatic compressed air energy storage system can adopt salt caves, artificial chambers and the like, the pressure bearing capacity of the gas storage device is within a certain range under the constraint of the self performance of the gas storage device. The outlet pressure of the last compressor of the compression stage should therefore be matched to the pressure-bearing capacity of the energy storage device, i.e. the outlet pressure of the last compressor is of a known value.
To facilitate thermodynamic process derivation, the following assumptions are made:
(1) The working medium air is ideal gas, and satisfies the ideal gas state equation pv=r g T；
(2) The heat exchanger, the separator, the pipeline, the gas storage device and the like in the system have no pressure loss, and the power consumption of the oil pump, the water pump and other devices in the system is ignored;
(3) In the compression stage, the mass flow of air is unchanged; if the inlet air is wet air, wet air mass flow is used when calculating the compression power, mass flow offset coefficient is introduced when mass conservation is calculated, and dry air mass flow is used when calculating the expansion power;
(4) In the compression stage, the inlet temperature and pressure of the first compressor are the ambient temperature and pressure and are known values;
(5) In the compression stage, the air temperature at the inlet of each compressor is the same and is the air inlet temperature under the influence of a cooler before the compressors;
(6) In the compression stage, the outlet temperatures of the other compressors except the last compressor are set to be the same, and the outlet temperatures are set as variables in the performance calculation process;
(7) An expansion stage, wherein the inlet pressure of the first expander is the same as the outlet pressure of the last compressor;
(8) The expansion stage is influenced by the performance of a heater in front of the expansion machines, and the inlet temperature of each expansion machine is the same;
(9) In the expansion stage, the outlet temperatures of the rest expansion machines except the last expansion machine are set to be the same, and the outlet temperatures are the variables in the calculation process;
(10) In the expansion stage, the outlet pressure of the final expander is ambient pressure and is a known value;
(11) The temperature difference between the cold and hot fluid in all the heat exchangers (the cooler in the compression process and the heater in the expansion process) in the system is the same.
In addition to the above assumptions, it is to be noted that:
(1) according to the ideal gas variable process equationFor either compressor, expander, when the inlet gas state is known, the outlet gas state p out 、T out Are dependent variables of each other, i.e. when one is quantitative the other is quantitative. All formulas in the invention adopt temperature as a main variable;
(2) since 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;
(3) since the outlet pressure of the last expander is known, the outlet temperature of the last expander is a dependent variable of the outlet pressure, not an unknown value;
(4) since the heat storage medium is applied to both the compression stage and the expansion stage, the inlet temperature of the expander is a dependent variable of the compressor outlet temperature and the heat exchanger pinch temperature difference, affected by the heat storage medium.
1) Performance analysis type advanced adiabatic compressed air energy storage system based on multiple efficiencies of compressor and expander
Based on the above assumption, and in combination with the first law of thermodynamics and the second law of thermodynamics, the calculation of the compression power, expansion power and electrical to electrical efficiency for an advanced adiabatic compressed air energy storage system containing any number of compressors and any number of expanders is:
(1) In equation- (3), there are some variables that are constrained to each other as follows:
the mass conservation exists in the compression stage and the expansion stage, thenWherein->Is the mass flow offset coefficient that exists under the influence of humid air.
Heat storage mediumT of the transmission action of (C) 1EX,in ＝T 1C,out -2 Δt, wherein Δt is the heat exchanger pinch temperature difference.
According to equation (1), the compression power can be calculated by specifying the mass air flow of the compression stage, the inlet and outlet temperatures of the first compressor, the inlet and outlet pressures of the first compressor, the final compressor, and the polytropic efficiency of each compressor.
According to equation (2), the expansion power can be calculated by specifying the mass air flow in the expansion stage, the inlet and outlet temperatures of the first expander, the inlet and outlet pressures of the first expander, the polytropic efficiency of each expander.
According to the formula (3), the compression time length and the expansion time length are specified, and the electric-to-electric efficiency of the advanced adiabatic compressed air energy storage system can be calculated.
For advanced adiabatic compressed air energy storage systems for determining application scenarios, the ambient temperature, ambient pressure and the pressure of the gas 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, and the compression process power can be calculated by only specifying the air mass flow rate of the compression stage, the outlet temperature of the first compressor and the polytropic efficiency of each compressor.
Accordingly, the first expander inlet pressure, the last expander outlet pressure of the expansion stage are known parameters. After the compression period and the expansion period are determined, the mass air flow in the expansion stage can be determined. After the pinch point temperature difference of the heat exchanger is specified, the inlet temperature of the first expander can be determined. Therefore, the expansion power can be calculated by only specifying the outlet temperature of the first expander in the expansion stage and the polytropic efficiency of each expander.
The electric-to-electric efficiency of the advanced adiabatic compressed air energy storage system can be calculated according to parameters such as compression power, compression time, expansion power, expansion time and the like and calculation results.
2) Isentropic efficiency and polytropic efficiency relationship for compressors and expanders
In engineering applications, some equipment manufacturers only provide isentropic efficiency of the equipment, and do not provide polytropic efficiency of the equipment. In order to solve the influence of the current situation on the performance calculation failure of the advanced adiabatic compressed air energy storage system, the relation between isentropic efficiency and polytropic efficiency needs to be built.
For any compressor, the isentropic efficiency and polytropic efficiency of the compressor are related as:
the inlet temperatures of all compressors are known. Except the last compressor, the outlet temperatures of the remaining compressors are variables that can affect the compression power.
The outlet temperature of the last compressor is a dependent variable of the outlet pressure and can be expressed as:
the isentropic efficiency of each compressor is converted into polytropic efficiency by the formulas (4) and (5), and the compression power can be calculated by the formula (1). During the calculation, no new calculation variables are introduced.
For any expander, the isentropic efficiency and polytropic efficiency of the expander are related as follows:
the inlet temperature of all the expanders is a dependent variable of the temperature difference between the outlet temperature of the compressor and the clamping point of the heat exchanger. Except the last expander, the outlet temperatures of the rest of the expanders are variables which can influence the expansion power.
The outlet temperature of the last expander is a function of the outlet pressure and can be expressed as:
the isentropic efficiency of each expander is converted into polytropic efficiency by the formulas (6) and (7), and the expansion power can be calculated by the formula (2). During the calculation, no new calculation variables are introduced.
After calculating the compression power and the expansion power, respectively, the electrical to electrical efficiency of the advanced adiabatic compressed air energy storage system may be calculated based on the compression time period and the expansion time period.
(1) The meaning of each symbol in the formula (7) is as follows:
examples
As shown in FIG. 1, the present invention is embodied in an advanced adiabatic compressed air energy storage system comprised of three compressors and three expanders and multiple heat exchangers.
In the compression stage, ambient air is compressed into high-temperature and high-pressure gas by three compressors. In order to recover high-temperature heat energy, the gas at the outlet of the compressor exchanges heat with a high-quality heat medium in the high-quality heat cooler, and then enters the water cooler for further cooling, so that the inlet temperatures of the three compressors are ensured to be the same as the ambient temperature. The separator is provided in the flow path, taking into account that the inlet air may be humid air. In the compression process, air enters the air storage device after being compressed for three times and cooled for many times.
The high-quality heat medium is stored in the high-quality hot and high-temperature storage tank after heat exchange and is used for heating high-pressure air in the expansion stage.
In the expansion stage, high-pressure normal-temperature air is led out from the air storage device, preheated by the water heater, and then flows into the high-quality heat heater to be heated into high-temperature high-pressure air by the high-temperature high-quality heat medium. Then flows into an expander to expand and do work. In the expansion stage, the air undergoes multiple heating and three expansion, the outlet pressure of the third expander is ambient pressure, and then the air flows into a water cooler, and the air cooled to the ambient temperature and the ambient pressure is discharged to the atmosphere.
In the calculation of the embodiment, there are the following assumptions:
(1) The air of the working medium is an ideal gas,
(2) The heat exchanger, the separator, the pipeline, the gas storage device and the like in the system have no pressure loss, and the power consumption of the oil pump, the water pump and other devices in the system is ignored;
(3) In the compression stage, the mass flow of air is unchanged;
(4) The ambient temperature was 20℃and the ambient pressure was 101.325kPa.
(5) In the compression stage, the inlet temperature of each compressor is ambient temperature, namely T, under the influence of a cooler before the compressors 1C,in ＝T 2C,in ＝T 3C,in ＝20℃；
(6) In 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；
(7) In the expansion stage, the inlet pressure of the first expander is p 1EX,in ＝20MPa；
(8) The expansion stage is influenced by the performance of the heater before the expansion machines, and the inlet temperature of each expansion machine is the same, namely T 1EX,in ＝T 2EX,in ＝T 3EX,in ；
(9) In the expansion stage, the outlet temperatures of the first expander and the second expander are the same, namely T 1EX,out T 2EX,out ；
(10) In the expansion stage, the outlet pressure of the final expander is ambient pressure, p 3EX,out ＝101.325kPa；
(11) The temperature difference of the clamping points of cold and hot fluid in all heat exchangers in the system is the same, and delta T=10 ℃;
(12) The upper limit of the temperature of the high-quality heat medium is 340 ℃, and the lower limit of the temperature is 80 ℃;
(13) Compression time is 8 hours and expansion time is 5 hours.
Embodiment case one:
in addition to the basic assumptions above, this case includes the following assumptions:
(1) The first compressor inlet is dry air;
(2) The polytropic efficiency of both the three compressors and the three expanders was 85.15%.
According to formulas (1) to (3), the formulas for calculating the compression power, the expansion power, and the electric-to-electric efficiency in this example can be written as:
because the inlet medium is dry air, the mass flow offset coefficient
When the temperature change interval of the outlet of the compressor is [230 ℃ and 380 ℃ and the temperature change interval of the outlet of the expander is [80 ℃ and 220 ℃, the change conditions of compression power, expansion power and electric-to-electric efficiency are respectively shown in fig. 2-4.
As can be seen from fig. 2 and equation (8), the compression power is T 1C,out There is a T as a single-valued function of (1) 1C,out The value is such that the compression power is minimal. On both sides of the minimum, with compressor outlet temperature T 1C,out Away from the minimum value, the compression power increases. At T 1C,out At 380 c, the compression power is at a maximum.
As shown in fig. 3, the expansion power is simultaneously subjected to T 1EX,out 、T 1EX,in Is a common influence of (a) and (b). Because the temperature difference between the clamping points of the high-quality heat cooler in the compression process is 10 ℃, the heat storage temperature of the high-quality heat medium and the compressorOutlet temperature T 1C,out There is always a difference. Since the upper temperature limit of the high-quality heat medium is 340 ℃, the temperature T of the outlet of the compressor 1C,out At temperatures above 350 ℃, the heat storage temperature of the high quality heat medium is still 340 ℃. Thus, during the expansion phase, the expander inlet temperature is up to 330 ℃. When the inlet temperature of the expander is 330 ℃, the outlet temperature T of the expander 1EX,out At [80 ℃,220 DEG C]The change, there is the operating point that makes the expansion power the biggest, and specific information is: expander inlet temperature T 1EX,in Temperature at expander outlet t=330℃ 1EX,out =120 ℃, expander power is 305.72MW.
When the outlet temperature T of the compressor 1C,out At [350 ℃,380℃ ]]The compression power increases with increasing outlet temperature as it changes. While at compressor outlet temperature T 1C,out At [350 ℃,380℃ ]]When changing, the inlet temperature T of the expander 1EX In is unchanged, and the power of the expander is along with the outlet temperature T of the expander 1EX,out But vary. Therefore, the outlet temperature T of the compressor is selected 1C,out And expander outlet temperature T 1EX,out The change in electrical to electrical efficiency is described and the results are shown in fig. 4. When the outlet temperature T of the compressor 1C,out At [230 ℃,380℃ ]]Expander outlet temperature T 1EX,out At [80 ℃,220 DEG C]There are operating points that optimize the electrical to electrical efficiency, the specific information is: compressor outlet temperature T 1C,out Temperature at expander outlet t=350℃ 1EX,out =120 ℃, the electrical to electrical efficiency is 83.11%.
According toIt can be calculated that when the electric to electric efficiency is optimal, the first compressor is 958.86kPa, the outlet pressure of the second compressor is 9.07MPa, the outlet pressure of the first expander is 3.44MPa, and the outlet pressure of the second expander is 593kPa.
When the electricity-to-electricity efficiency is optimal, the detailed information of the thermodynamic flow is as follows: dry air flows into the first compressor at 20 ℃ and 101.325kPa, the mass flow rate is 1140000kg/h, and the outlet state of the first compressor is 350 ℃ and 958.86kPa; after heat exchange by the cooler, the refrigerant flows into the second compressor at 20 ℃ and 958.86kPa, and the outlet state of the second compressor is 350 ℃ and 9.07MPa; after heat exchange by the cooler, the refrigerant flows into the last compressor at 20 ℃ and 9.07MPa, and the outlet pressure of the last compressor is 20MPa. Then heat exchanging is carried out by a cooler, and the heat exchanged water enters a gas storage device for storage in a state of 20 ℃ and 20MPa. When power generation is needed, normal-temperature high-pressure air flows out of the air storage device, flows through the heater to be heated, flows into the first expander at 330 ℃ and 20MPa, and has a mass flow rate of 1824000kg/h, and an outlet state of the first expander is 120 ℃ and 3.44MPa; the heat is supplied to the second expander in a state of being heated to 330 ℃ and 3.44MPa in the heater, and the outlet state of the heat is 120 ℃ and 593kPa; the mixture was heated to 330℃in a heater and was fed into a final expander at 593kPa, and expanded to 101.325kPa and discharged. The compression power of the whole process is 229.90MW, the expansion power is 305.72MW, and the electric to electric efficiency is 83.11%.
Implementation case two:
in addition to the basic assumptions above, this case includes the following assumptions:
(1) The inlet of the first compressor is humid air, and the relative humidity is 0.87;
(2) The isentropic efficiency of the three compressors is 80%, and the isentropic efficiency of the three expanders is 85.6%.
Mass flow rate shift coefficient of humid air according to thermodynamic basic principleWhere d is the moisture content of the humid air.
Since the data is known in this example as isentropic efficiency of the compressor and expander, in order to calculate compression power, expansion power and electrical to electrical efficiency, it is first necessary to convert the isentropic efficiency into polytropic efficiency. As can be seen from equation (4), the polytropic efficiency calculations of the first, second and last compressors are:
t in formula (13) according to formula (5) 3C,out The calculation method comprises the following steps:
as can be seen from equation (6), the polytropic efficiency calculations of the first expander, the second expander and the third expander are:
t in formula (17) according to formula (7) 3EX,out The calculation method comprises the following steps:
when equations (11) - (13) and equations (15) - (17) are substituted into equations (8) - (10) and the compressor outlet temperature change interval is [230 ℃,380 ℃ and the expander outlet temperature change interval is [80 ℃,220 ℃), the changes of compression power, expansion power and electric to electric efficiency are shown in fig. 5-7, respectively.
In this case, the compression power is T 1C,out Single value function of (2)Number, there is one T 1C,out The value is such that the compression power is minimal. On both sides of the minimum, with compressor outlet temperature T 1C,out Away from the minimum value, the compression power increases. At T 1C,out At 380 c, the compression power is at a maximum as shown in fig. 5.
As shown in fig. 6, the expansion power is simultaneously subjected to T 1EX,out 、T 1EX,in Is a common influence of (a) and (b). Because the temperature difference between the clamping points of the high-quality heat cooler in the compression process is 10 ℃, the heat storage temperature of the high-quality heat medium and the outlet temperature T of the compressor 1C,out There is always a difference. Since the upper temperature limit of the high-quality heat medium is 340 ℃, the temperature T of the outlet of the compressor 1C,out At temperatures above 350 ℃, the heat storage temperature of the high quality heat medium is still 340 ℃. Thus, during the expansion phase, the expander inlet temperature is up to 330 ℃. When the inlet temperature of the expander is 330 ℃, the outlet temperature T of the expander 1EX,out At [80 ℃,220 DEG C]The change, there is the operating point that makes the expansion power the biggest, and specific information is: expander inlet temperature T 1EX,in Temperature at expander outlet t=330℃ 1EX,out =125 ℃, expander power is 300.83MW.
When the outlet temperature T of the compressor 1C,out At [350 ℃,380℃ ]]The compression power increases with increasing outlet temperature as it changes. While at compressor outlet temperature T 1C,out At [350 ℃,380℃ ]]When changing, the inlet temperature T of the expander 1EX,in The power of the expander is unchanged along with the outlet temperature T of the expander 1EX,out But vary. Therefore, the outlet temperature T of the compressor is selected 1C,out And expander outlet temperature T 1EX,out The change in electrical to electrical efficiency is described and the results are shown in fig. 7. When the outlet temperature T of the compressor 1C,out At [230 ℃,380℃ ]]Expander outlet temperature T 1EX,out At [80 ℃,220 DEG C]There are operating points that optimize the electrical to electrical efficiency, the specific information is: compressor outlet temperature T 1C,out Temperature at expander outlet t=350℃ 1EX,out =125 ℃, the electrical to electrical efficiency is 81.37%.
According toIt can be calculated that when the electric to electric efficiency is optimal, the first compressor is 958.97kPa, the outlet pressure of the second compressor is 9.08MPa, the outlet pressure of the first expander is 3.40MPa, and the outlet pressure of the second expander is 579.37kPa.
When the electricity-to-electricity efficiency is optimal, the detailed information of the thermodynamic flow is as follows: air flows into the first compressor at 20 ℃, 101.325kPa and a relative humidity of 0.87, a mass flow rate of 1140000kg/h, and a first compressor outlet state of 350 ℃ and 958.97kPa; after heat exchange by a cooler, the heat flows into a second compressor at 20 ℃ and 958.97kPa, and the outlet state of the second compressor is 350 ℃ and 9.08MPa; after heat exchange by the cooler, the refrigerant flows into the last compressor at 20 ℃ and 9.08MPa, and the outlet pressure of the last compressor is 20MPa. Then heat exchanging is carried out by a cooler, and the heat exchanged water enters a gas storage device for storage in a state of 20 ℃ and 20MPa. When power generation is needed, normal-temperature high-pressure air flows out of the air storage device, flows through the heater to be heated, flows into the first expander at 330 ℃ and 20MPa, and has a mass flow rate of 1800272kg/h, and an outlet state of the first expander is 125 ℃ and 3.40MPa; the heat was applied to the second expander at 330℃under 3.40MPa, and the outlet from the second expander was applied at 125℃under 579.37kPa; the mixture was heated to 330℃in a heater and was fed into a final expander at 579.37kPa, and expanded to 101.325kPa and discharged. The compression power of the whole process is 231.06MW, the expansion power is 300.83MW, and the electric to electric efficiency is 81.37%.
While the invention has been described in detail in the foregoing general description and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that modifications and improvements can be made thereto. Accordingly, such modifications or improvements may be made without departing from the spirit of the invention and are intended to be within the scope of the invention as claimed.
Claims (10)
1. The analysis method of the performance of the advanced adiabatic compressed air energy storage system is characterized by comprising the following steps of:
when the application scene of the advanced adiabatic compressed air energy storage system is determined, determining the outlet temperature of the last compressor according to the inlet pressure, the inlet temperature and the outlet temperature of the first compressor, the outlet pressure of the last compressor and the isentropic efficiency of each compressor; determining the polytropic efficiency of each compressor according to the inlet temperature, the outlet temperature and the isentropic efficiency of the first compressor; determining the compression power of the compression stage according to the inlet temperature and the outlet temperature of the first compressor, the polytropic efficiency of each compressor and the mass flow of the compression stage;
determining the inlet temperature of the first expander according to the outlet temperature of the first compressor and the temperature difference of the clamping points of the heat exchanger; determining the outlet temperature of the last expander according to the inlet pressure, the inlet temperature and the outlet temperature of the first expander, the outlet pressure of the last expander and the isentropic efficiency of each expander; determining the polytropic efficiency of each expander according to the inlet temperature, the outlet temperature and the isentropic efficiency of the first expander; determining expansion power of an expansion stage according to inlet temperature and outlet temperature of the first expander, polytropic efficiency of each expander and mass flow of the expansion stage;
the electrical to electrical efficiency of the advanced adiabatic compressed air energy storage system is determined based on the compression power, the compression duration, the expansion power, and the expansion duration.
2. The method of claim 1, wherein the outlet temperature of the last compressor is:
wherein p is 1C,in For the inlet pressure, p, of the first compressor aC,out T is the outlet pressure of the last compressor 1C,in For the inlet temperature of the first compressor, T 1C,out For the outlet temperature, η of the first compressor s,xC Isentropic efficiency, η, of any compressor s,aC For isentropic efficiency of the last compressor, a is the total number of compressors.
3. The method of claim 2, wherein the multiple efficiencies of each compressor are:
wherein T is xC,out Outlet temperature T of any compressor except the last compressor xC,out ＝T 1C,out 。
4. A method of resolving the performance of an advanced adiabatic compressed air energy storage system as claimed in claim 3, wherein the compression stage has a compression power of:
wherein,for mass flow in compression stage, κ is air insulation index, R g Is a gas constant.
5. The method of claim 4, wherein the inlet temperature of each expander is:
T 1EX,in ＝T 1C,out -2ΔT
wherein T is 1EX,in For the inlet temperature of the first expander, T 1C,out The outlet temperature of the first compressor, deltaT, is the pinch temperature difference of the heat exchanger.
6. The method of claim 5, wherein the final expander outlet temperature is:
wherein p is 1EX,in For the inlet pressure, p, of the first expander bEX,out T is the outlet pressure of the final expander 1EX,out For the outlet temperature, η of the first expander s,yEX Isentropic efficiency, η, of any expander s,bEX Isentropic efficiency for the last expander, b is the total number of expanders.
7. The method of claim 6, wherein the multiple efficiencies of each expander are:
wherein T is yEX,out Is the outlet temperature of either expander.
8. The method of claim 7, wherein the expansion power of the expansion phase is:
wherein,is the mass flow rate in the expansion stage.
9. The method of claim 8, wherein the advanced adiabatic compressed air energy storage system has an electrical to electrical efficiency of:
wherein h is C For the duration of compression, h EX Is the expansion duration.
10. The method for resolving the performance of an advanced adiabatic compressed air energy storage system according to claim 9, wherein mass conservation relations exist among mass flow in the compression stage, mass flow in the expansion stage, compression duration and expansion duration:
wherein,is the mass flow offset coefficient that exists under the influence of humid air.
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