Transcritical co2 cycle power generation system

Abstract

The application discloses a transcritical CO2 cycle power generation system, which comprises a transcritical CO2 cycle system, a turbine generator, a heat exchange system and a temperature control machine. The transcritical CO2 cycle system comprises a working medium inlet and a working medium outlet. The working medium outlet of the turbine generator is communicated with the working medium inlet. The turbine generator is communicated with an external power grid through a low-voltage power grid. The working medium three-way valve of the heat exchange system is communicated with the working medium outlet. Two outlet ends are respectively communicated with a working medium injection inlet through a heater and a phase change energy storage array. The heat source outlet of the temperature control machine is respectively communicated with the phase change energy storage array and the heat source inlet end of the heater through a heat source three-way valve. The temperature control machine and the heat source three-way valve are respectively configured to adjust the heat source temperature and the heat source flow rate injected into the phase change energy storage array and the heater according to the power demand of the external power grid, so as to adjust the heat source flow rate and the heat source temperature injected into the heater, thereby adjusting the heat absorbed by the CO2 liquid working medium injected into the turbine generator, and adjusting the power generation capacity of the turbine generator, so as to adapt to the change of the power demand of the external power grid.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of generator technology characterized by the application of special working fluid, in particular to a transcritical CO2 cycle power generation system. BACKGROUND

[0002] At present, steam power plants based on Rankine cycle and gas turbine power plants based on Brayton cycle are widely used thermal power conversion systems, but both of them rely on primary energy and fossil fuels, and emit a large amount of carbon emissions in the actual production process. Therefore, developing renewable energy technology, improving energy utilization efficiency and developing efficient and low-carbon energy conversion technology are important technical means to realize green and sustainable development of economic society.

[0003] At present, carbon dioxide is widely used in thermal power conversion systems by researchers due to its environmental friendliness, safety, thermal stability and the advantage of being easy to heat to supercritical state. Supercritical carbon dioxide (sCO2) power cycle has the advantages of high thermal efficiency, compact components and simple power plant construction, and can be directly used to obtain medium and high temperature energy, and has a wide range of applications, including nuclear power generation, solar power generation and other fields.

[0004] In order to obtain high efficiency, in the power cycle with CO2 as the working medium, the CO2 at the inlet of the compressor is usually in a state close to but slightly higher than the critical point. However, the thermal physical properties of CO2 will change significantly near the critical point. The most important problem caused by this property mutation is that the fluid density at the inlet of the compressor will change sharply with the influence of the ambient temperature, which will cause the system to run unstable due to the change of mass flow.

[0005] The patent application with publication number CN111852602A discloses a transcritical carbon dioxide power generation system based on a vortex tube. The system pressurizes and heats the low-pressure protective liquid CO2 fluid through a CO2 working fluid pump and a heater, injects the high-pressure superheated CO2 fluid into a CO2 turbine, thereby driving the generator to generate electricity, and the CO2 fluid discharged from the CO2 turbine is cooled by a cooler and injected into the vortex tube for separation. The separated superheated gaseous CO2 fluid is pressurized by a compressor and then injected into the vortex tube for separation again, until all of them are converted into low-pressure saturated liquid CO2 fluid, thereby solving the problem of difficult condensation of CO2 in high temperature environment.

[0006] However, in the prior art, the heat provided by the heat source is generally stable, so that the power generated by the power generation system is also stable without special circumstances. The prior art does not consider the influence of the power demand change of the external power grid, and cannot dynamically adjust the power generation power of the power generation system according to the power demand of the external power grid. For example, when the power demand of the external power grid decreases and the power generation power of the power generation system is greater than the power demand of the external power grid, the excess power generated by the power generation system is wasted. Conversely, when the power demand of the external power grid increases and the power generation power of the power generation system is less than the power demand of the external power grid, the power generation system cannot meet the power demand of the external power grid. SUMMARY

[0007] In view of the deficiencies in the prior art, the present application provides a transcritical CO2 cycle power generation system. The power generation power of the power generation system can be dynamically adjusted, and the specific technical solutions are as follows:

[0008] A transcritical CO2 cycle power generation system is provided. In a first implementation mode, the transcritical CO2 cycle power generation system comprises:

[0009] The transcritical CO2 cycle system comprises a working medium inlet and a working medium outlet.

[0010] The turbine generator comprises a working medium injection port and a working medium discharge port, and the working medium discharge port is connected to the working medium inlet. The turbine generator is connected to the external power grid through a low-voltage power grid.

[0011] The heat exchange system comprises a working medium three-way valve, and the inlet end of the working medium three-way valve is connected to the working medium outlet. The two outlet ends are connected to the working medium injection port through a heater and a phase change energy storage array, respectively.

[0012] The temperature control machine is provided with a heat source inlet and a heat source outlet. The heat source outlet is connected to the heat source inlet end of the phase change energy storage array and the heater through a heat source three-way valve, respectively.

[0013] The working medium three-way valve and the heat source three-way valve are respectively configured to adjust the flow of the heat source injected into the phase change energy storage array and the heater and the flow of the working medium according to the power demand of the external power grid.

[0014] In a second implementation mode, the transcritical CO2 cycle system comprises:

[0015] The vortex tube comprises a CO2 working medium inlet, a CO2 saturated liquid outlet, a CO2 saturated vapor outlet, and a CO2 superheated vapor outlet. The CO2 working medium inlet is connected to the working medium inlet.

[0016] The liquid mixer comprises two liquid inlet ends and a liquid discharge end. One of the liquid inlet ends is connected to the CO2 saturated liquid outlet, and the liquid discharge end is connected to the working medium outlet.

[0017] The gas mixer comprises two gas inlet ends and a gas outlet end, and the two gas inlet ends are connected with the CO2 saturated vapor outlet and the CO2 superheated vapor outlet respectively.

[0018] The compressor comprises a gas inlet and a liquid outlet, the gas inlet is connected with the gas outlet end, and the liquid outlet is connected with another liquid inlet end.

[0019] In the third implementation, in combination with the second implementation, the transcritical CO2 cycle system further comprises a pre-cooler, two ends of the pre-cooler are connected with the CO2 working medium inlet and the working medium inlet respectively.

[0020] In the fourth implementation, in combination with the third implementation, the transcritical CO2 cycle system further comprises a high-temperature regenerator, the high-temperature regenerator comprises two high-temperature heat exchange pipes, one of the high-temperature heat exchange pipes is connected with the liquid outlet and the working medium outlet, and the other high-temperature heat exchange pipe is connected with the pre-cooler and the working medium inlet.

[0021] In the fifth implementation, in combination with the fourth implementation, the transcritical CO2 cycle system further comprises a low-temperature regenerator, the low-temperature regenerator comprises two low-temperature heat exchange pipes, one of the low-temperature heat exchange pipes is connected with the CO2 saturated liquid outlet and the liquid inlet end, and the other low-temperature heat exchange pipe is connected with the high-temperature heat exchange pipe and the pre-cooler.

[0022] In the sixth implementation, in combination with the fifth implementation, the transcritical CO2 cycle system further comprises a booster pump, the booster pump is connected with the CO2 saturated liquid outlet and the low-temperature heat exchange pipe.

[0023] In the seventh implementation, in combination with the fifth implementation, the transcritical CO2 cycle system further comprises a heat-consuming device, the low-temperature heat exchange pipe is connected with the pre-cooler through the heat-consuming device.

[0024] In the eighth implementation, in combination with the sixth implementation, the low-voltage power grid is electrically connected with the temperature control machine, the compressor and the booster pump respectively.

[0025] In the ninth implementation, in combination with the first implementation, the heat source flow and the working medium flow injected into the phase change energy storage array and the heater are adjusted according to the power demand of the external power grid, and the adjusting comprises the following steps:

[0026] When the power demand of the external power grid is in a low load, the heat source flow injected into the phase change energy storage array and the heater is determined according to the following calculation formula:

[0027] ;

[0028] ;

[0029] When the power demand of the external power grid is at high load, the heat source flow injected into the heater is determined according to the following calculation formula:

[0030] .

[0031] In a tenth implementation manner, the first implementation manner is combined, further comprising a photovoltaic power generation system, and / or a wind power generation system, and / or a battery energy storage system, which are electrically connected with the low-voltage power grid.

[0032] Beneficial effects: By adopting the transcritical CO2 cycle power generation system, the temperature of the heat source injected into the phase change energy storage array and the heater can be adjusted by the temperature control machine, and the heat source flow injected into the phase change energy storage array and the heater can be adjusted by the heat source three-way valve. By adjusting the heat source flow and temperature injected into the heater, the heat absorbed by the CO2 liquid working medium injected into the turbine generator can be adjusted, so that the power generation of the turbine generator is adjusted to adapt to the power demand change of the external power grid. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present application, the drawings required to be used in the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn according to the actual proportion.

[0034] Figure 1 The schematic diagram of the transcritical CO2 cycle power generation system provided by an embodiment of the present application;

[0035] Reference signs:

[0036] 1-compressor, 2-turbine, 3-turbine generator, 4-high-temperature regenerator, 5-liquid mixer, 6-low-temperature regenerator, 7-boost pump, 8-heat-consuming device, 9-vortex tube, 10-pre-cooler, 11-gas mixer, 12-photovoltaic power generation system, 13-transformer, 14-wind power generation system, 15-battery energy storage system, 16-inverter, 17-heat source three-way valve, 18-phase change energy storage array, 19-working medium three-way valve, 20-heater, 21-temperature control machine. DETAILED DESCRIPTION

[0037] The embodiments of the technical solutions of the present application will be described in detail below in combination with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0038] As Figure 1 shown in the schematic diagram of the transcritical CO2 cycle power generation system, the power generation system comprises:

[0039] The transcritical CO2 cycle system comprises a working fluid inlet and a working fluid outlet.

[0040] The turbine generator 3 comprises a working fluid injection inlet and a working fluid discharge outlet, which is connected to the working fluid inlet, and the turbine generator 3 is connected to an external power grid through a low-voltage power grid.

[0041] The heat exchange system comprises a working fluid three-way valve 19, the inlet end of which is connected to the working fluid outlet, and the two outlet ends are connected to the working fluid injection inlet through the heater 20 and the phase change energy storage array 18 respectively.

[0042] The temperature control machine 21 is provided with a heat source inlet and a heat source outlet, and the heat source outlet is connected to the heat source inlet end of the phase change energy storage array 18 and the heater 20 through the heat source three-way valve 17 respectively.

[0043] The temperature control machine 21 and the heat source three-way valve 17 are respectively configured to adjust the heat source temperature and the heat source flow injected into the phase change energy storage array 18 and the heater 20 according to the power demand of the external power grid.

[0044] Specifically, the power generation system comprises a transcritical CO2 cycle system, a turbine generator 3, a heat exchange system and a temperature control machine 21. Among them, the high-temperature CO2 working fluid is injected into the turbine 2 of the turbine generator 3 through the working fluid injection inlet, and after doing work, it is discharged from the working fluid discharge outlet, and then injected into the transcritical CO2 cycle system through the working fluid inlet to recover into low-temperature CO2 working fluid. The low-temperature CO2 working fluid is injected into the working fluid three-way valve 19 through the working fluid outlet, and the working fluid three-way valve 19 can adjust the low-temperature CO2 working fluid flow injected into the heater 20 and the phase change energy storage array 18. After the low-temperature CO2 liquid working fluid exchanges heat with the heater 20 and the phase change energy storage array 18 respectively, it recovers into high-temperature CO2 working fluid and is injected into the turbine 2 again to generate electricity.

[0045] In the process of power generation, the heat source can be injected into the heater 20 and the phase change energy storage array 18 through the temperature control machine 21 and the heat source three-way valve 17 respectively. The temperature control machine 21 can adjust the injected heat source temperature, the heat source three-way valve 17 can distribute the heat source energy injected into the heater 20 and the phase change energy storage array 18, and by cooperating with the working fluid three-way valve 19, the flow and temperature of the high-temperature CO2 working fluid injected into the turbine 2 can be controlled, so as to adjust the power generation power of the turbine generator 3 to adapt to the power demand change of the external power grid.

[0046] For example, when the external grid power demand increases, the output ac of the working fluid three-way valve 19 can be opened, and the output ai of the working fluid three-way valve 19 can be opened. At the same time, the output c of the heat source three-way valve 17 can be closed, and the output i of the heat source three-way valve 17 can be fully opened. In this way, the heat source working fluid can be injected into the heater 20 to heat the injected CO2 working fluid. At the same time, the phase change energy storage array 18 can also inject the CO2 working fluid to heat the heat stored in the phase change energy storage array 18 when the external grid power demand decreases.

[0047] The high-temperature CO2 working fluid heated by the phase change energy storage array 18 and the heater 20 is injected into the turbine 2 through the working fluid injection port to do work. At this time, all heat sources are injected into the heater 20, so that the heat absorption of the CO2 working fluid reaches the maximum, thereby increasing the output power of the turbine 2, and thereby increasing the power generation of the turbine generator 3 to meet the increased external grid power demand.

[0048] Furthermore, the heat source temperature of the heat source working fluid can be adjusted by the temperature control machine 21 according to the degree of increase of the external grid power demand. If the degree of increase is small, the temperature control machine 21 can not be started. If the degree of increase is large, the temperature control machine 21 can be started to heat the heat source working fluid, thereby increasing the heat of the heat source working fluid, and further increasing the heat absorption of the CO2 working fluid.

[0049] Conversely, when the external grid power demand decreases, the output ac of the working fluid three-way valve 19 can be closed, and the output c of the heat source three-way valve 17 can be opened. At this time, part of the heat source working fluid can be injected into the phase change energy storage array 18 along the output c. The phase change material in the phase change energy storage array 18 can absorb heat and melt, and store the energy of the heat source working fluid in the phase change energy storage array 18. Another part of the heat source working fluid can be injected into the heater 20 from the output i to heat the CO2 working fluid. The flow of the heat source working fluid injected into the heater 20 decreases, and the heat absorbed by the CO2 working fluid also decreases, thereby reducing the output power of the turbine 2, and further reducing the power generation of the turbine generator 3 to meet the reduced external grid power demand.

[0050] The heat source three-way valve 17 can be a three-way flow regulating valve, which can adjust the flow of the heat source injected into the phase change energy storage array 18 and the heater 20 according to the degree of decrease of the external grid power demand. If the degree of decrease is small, most of the heat source working fluid can be injected into the heater 20. If the degree of decrease is large, most of the heat source working fluid can be injected into the phase change energy storage array 18, so that most of the heat is stored in the phase change energy storage array 18 to avoid waste.

[0051] In the embodiment, the transcritical CO2 cycle system can include:

[0052] The vortex tube 9 includes a CO2 working medium inlet q, a CO2 saturated liquid outlet t, a CO2 saturated vapor outlet r and a CO2 superheated vapor outlet o, the CO2 working medium inlet q is communicated with the working medium inlet;

[0053] The liquid mixer 5 includes two liquid inlets and a liquid outlet, one of the liquid inlets is communicated with the CO2 saturated liquid outlet t, and the liquid outlet is communicated with the working medium outlet;

[0054] The gas mixer 11 includes two gas inlets and a gas outlet, the two gas inlets are respectively communicated with the CO2 saturated vapor outlet r and the CO2 superheated vapor outlet o;

[0055] The compressor 1 includes a gas inlet and a liquid outlet, the gas inlet is communicated with the gas outlet, and the liquid outlet is communicated with the other liquid inlet.

[0056] Specifically, the transcritical CO2 cycle system includes the vortex tube 9, the liquid mixer 5, the gas mixer 11 and the compressor 1. The low-temperature CO2 working medium discharged from the turbine 2 can be injected into the vortex tube 9 through the CO2 working medium inlet q of the vortex tube 9.

[0057] It should be understood that the vortex tube 9 is a simple and compact pressure reduction device without moving parts and does not consume any additional power, and is easy to operate and maintain. By using the Ranque-Hilsch effect, the vortex tube 9 can simultaneously separate a flow of fluid into two streams of cold and hot fluid with different temperatures. When high-pressure gas is injected into the vortex tube 9, the high-pressure gas will be separated into three parts, which are saturated vapor, saturated liquid and superheated gas. Compared with the traditional low-temperature condenser, the use of the vortex tube 9 realizes the self-condensation of CO2 at the near-critical point, and solves the problem of unstable operation of the system caused by the sudden change of the properties of CO2 near the near-critical point.

[0058] Therefore, the vortex tube 9 can split the low-temperature CO2 working medium vapor. The split CO2 saturated liquid can be discharged from the CO2 saturated liquid outlet t of the vortex tube 9 and injected into the liquid mixer 5 through the pipeline. The split CO2 saturated vapor and CO2 superheated vapor of the vortex tube 9 can be discharged from the CO2 saturated vapor outlet r and the CO2 superheated vapor outlet o respectively and injected into the gas mixer 11 through the pipeline respectively. After the CO2 saturated vapor and the CO2 superheated vapor are fully mixed in the gas mixer 11, the mixed gas of the CO2 saturated vapor and the CO2 superheated vapor can be injected into the compressor 1, and the mixed gas of the CO2 saturated vapor and the CO2 superheated vapor is compressed into CO2 liquid by the compressor 1 and discharged from the liquid outlet. The CO2 liquid discharged from the liquid outlet is injected into the liquid mixer 5 through the pipeline, and after being fully mixed with the CO2 saturated liquid in the liquid mixer 5, it is injected into the heat exchange system through the working medium three-way valve 19.

[0059] In the embodiment, the transcritical CO2 cycle system further comprises a pre-cooler 10, two ends of the pre-cooler 10 are communicated with the CO2 working medium inlet q and the working medium inlet respectively.

[0060] Specifically, the pre-cooler 10 is further arranged between the turbine 2 and the vortex tube 9, the pre-cooler 10 comprises a refrigeration pipe and a working medium pipe, an input end k and an output end l of the refrigeration pipe are communicated with a circulating cold source, so that the cold source working medium can flow in the refrigeration pipe. Two ends of the working medium pipe are communicated with the working medium inlet and the CO2 working medium inlet q of the vortex tube 9 respectively. In this way, the low-temperature CO2 working medium can exchange heat with the cold source working medium flowing in the refrigeration pipe before being injected into the vortex tube 9, so as to further reduce the temperature of the low-temperature CO2 working medium, make the CO2 working medium enter the two-phase region, so that the vortex tube 9 can carry out two-phase separation, and the energy consumed in the compression process can be reduced.

[0061] In the embodiment, the transcritical CO2 cycle system further comprises a high-temperature regenerator 4, the high-temperature regenerator 4 comprises two high-temperature heat exchange pipes, one of the high-temperature heat exchange pipes is communicated with the liquid outlet end and the working medium outlet, and the other high-temperature heat exchange pipe is communicated with the pre-cooler 10 and the working medium inlet.

[0062] Specifically, the high-temperature regenerator 4 is further arranged between the pre-cooler 10 and the working medium inlet, the high-temperature regenerator 4 comprises two high-temperature heat exchange pipes. An input end z of one of the high-temperature heat exchange pipes is communicated with the working medium inlet, and an output end aa is connected to the working medium pipe of the pre-cooler 10. An input end x of the other high-temperature heat exchange pipe is communicated with the liquid outlet end of the liquid mixer 5, and an output end y is communicated with the working medium outlet.

[0063] In this way, the low-temperature CO2 working medium injected from the working medium inlet can be injected into the high-temperature heat exchange pipe to exchange heat with the CO2 liquid injected from the liquid mixer 5 in the other high-temperature heat exchange pipe, and the heated CO2 liquid can be injected into the heat exchange system from the working medium outlet for further heating. Thus, the heat in the low-temperature CO2 working medium is recycled, and the energy consumption is further reduced. Moreover, the temperature of the low-temperature CO2 working medium injected into the pre-cooler 10 can be reduced in advance, and the cooling effect is improved.

[0064] In the embodiment, the transcritical CO2 cycle system further comprises a low-temperature regenerator 6, the low-temperature regenerator 6 comprises two low-temperature heat exchange pipes, one of the low-temperature heat exchange pipes is communicated with the CO2 saturated liquid outlet t and the liquid inlet end, and the other low-temperature heat exchange pipe is communicated with the high-temperature heat exchange pipe and the pre-cooler 10.

[0065] Specifically, a low-temperature regenerator 6 is further arranged between the high-temperature regenerator 4 and the pre-cooler 10. The low-temperature regenerator 6 can heat the CO2 saturated liquid discharged from the CO2 saturated liquid outlet t of the vortex tube 9 by using the heat in the low-temperature CO2 working medium after heat exchange in the high-temperature regenerator 4, so as to increase the temperature of the CO2 saturated liquid, further recover the heat in the low-temperature CO2 working medium, and reduce the heat consumed for heating the CO2 working medium.

[0066] In the embodiment, the low-temperature regenerator 6 includes two low-temperature heat exchange tubes. One low-temperature heat exchange tube is connected at the input end u to the CO2 saturated liquid outlet t of the vortex tube 9 and at the output end v to the liquid inlet end of the liquid mixer 5. The other low-temperature heat exchange tube is connected at the input end to the output end aa of the high-temperature regenerator and at the output end ab to the working medium tube of the pre-cooler 10.

[0067] In this way, the low-temperature CO2 working medium cooled in the high-temperature regenerator 4 can be injected into one of the low-temperature heat exchange tubes of the low-temperature regenerator 6 and heat exchanged with the CO2 saturated liquid injected into the other low-temperature heat exchange tube, so as to heat the CO2 saturated liquid discharged from the vortex tube 9. The heated CO2 saturated liquid can be injected into the liquid mixer 5 and mixed with the CO2 liquid discharged from the compressor 1.

[0068] In the embodiment, the transcritical CO2 cycle system further includes a booster pump 7 connected to the CO2 saturated liquid outlet t and the low-temperature heat exchange tube.

[0069] Specifically, the booster pump 7 is arranged between the CO2 saturated liquid outlet t of the vortex tube 9 and the input end u of the low-temperature regenerator 6. The booster pump 7 can boost the CO2 saturated liquid discharged from the CO2 saturated liquid outlet t, so as to increase the liquid pressure of the CO2 saturated liquid and keep the pressure of the CO2 saturated liquid the same as the pressure of the CO2 liquid discharged from the compressor 1, thereby increasing the inlet pressure of the CO2 working medium injected into the turbine 2 to generate power.

[0070] In the embodiment, the transcritical CO2 cycle system further includes a heat-consuming device 8. The low-temperature heat exchange tube is connected to the pre-cooler 10 through the heat-consuming device 8.

[0071] Specifically, the heat-consuming device 8 can be arranged between the working medium tube of the pre-cooler 10 and the output end ab of the low-temperature regenerator 6. The heat-consuming device 8 can supply heat to users, such as a heating device. The heat-consuming device 8 can recover and utilize the heat of the low-temperature CO2 working medium and further reduce the temperature of the low-temperature CO2 working medium injected into the pre-cooler 10.

[0072] In the embodiment, optionally, the low-voltage power grid is electrically connected with the temperature control machine 21, the compressor 1 and the booster pump 7 respectively. Specifically, the low-voltage power grid can be connected to the external power grid through the transformer 13. Part of the electric energy generated by the turbine generator 3 can be supplied to the temperature control machine 21, the compressor 1 and the booster pump 7 in the system through the low-voltage power grid. Another part can be supplied to the external power grid.

[0073] In the embodiment, optionally, a photovoltaic power generation system 12, and / or a wind power generation system 14, and / or a battery energy storage system 15 are further included, and all are electrically connected with the low-voltage power grid.

[0074] Specifically, the photovoltaic power generation system 12, and / or the wind power generation system 14, and / or the battery energy storage system 15 can be connected to the low-voltage power grid. The photovoltaic power generation system 12 can generate electricity by using sunlight, and the electric energy generated by the photovoltaic power generation system 12 can be converted into a voltage suitable for the low-voltage power grid through a DC / AC conversion module and the transformer 13. Similarly, the wind power generation system 14 can generate electricity by using wind power, and the electric energy generated by the wind power generation system 14 can be converted into a voltage suitable for the low-voltage power grid through a DC / AC conversion module and the transformer 13.

[0075] The electric energy generated by the wind power generation system 14 and the photovoltaic power generation system 12 can provide additional electric power for the operation of the entire system to supplement the electric power generated by the turbine generator 3 when the electric power generated by the turbine generator 3 is insufficient, so as to maintain the booster pump 7, the compressor 1 and the temperature controller to continue to work normally.

[0076] When the electric power generated by the wind power generation system 14, the photovoltaic power generation system 12 and the turbine generator 3 is sufficient and has a surplus, the excess electric power can be input into the battery through the inverter 16 for storage. When the power demand of the external power grid increases, the electric power released by the battery can be used to supplement the insufficient part of the turbine generator 3.

[0077] In the embodiment, optionally, the working fluid flow and the heat source flow injected into the phase change energy storage array 18 and the heater 20 are adjusted according to the power demand of the external power grid, including:

[0078] When the power demand of the external power grid is in a low load state, and the battery energy storage system is saturated, at this time, the additional electric energy generated by the new energy system such as the wind power generation system 14 and the photovoltaic power generation system 12 can be input into the phase change energy storage array 18 for storage, and part of the heat source working fluid flowing from the heat source three-way valve can be injected into the heater 20 through the output end i to maintain the stable operation of the power generation system, and the remaining part can be injected into the phase change energy storage array 18 through the output end c to store the heat source. The heat source working fluid flow distribution of the output end i and the output end c of the heat source three-way valve 17 can be calculated according to the following calculation formula:

[0079] ;

[0080] ;

[0081] wherein, is the heat source flow rate injected into the heater before the demand change, is the heat source enthalpy injected into the heater before the demand change, is the heat source flow rate output by the temperature controller before the demand change, is the heat source flow rate injected into the temperature controller before the demand change, is the heat source enthalpy output by the temperature controller before the demand change, which can be directly calculated by monitoring the temperature and pressure of the heat source output by the corresponding output end of the temperature controller and using existing enthalpy calculation software, is the heat source enthalpy injected into the heater after the demand change and again stable, is the heat source flow rate injected into the heater after the demand change and again stable, is the heat source flow rate injected into the phase change energy storage array after the demand change and again stable;

[0082] When the power demand of the external power grid is in a high load state, the electric heating temperature controller stops heating. Part of the CO2 working medium injected into the working medium three-way valve 19 is injected into the phase change energy storage array 18 from the output end ac, and the output end ac of the working medium three-way valve 19 can output CO2 working medium at the maximum flow rate of the phase change energy storage array 18. The remaining part can be injected into the heater 20 along the output end ai to absorb the heat of the heat source working medium. The output end c of the heat source three-way valve 17 can be closed, and all the injected heat source working medium is injected into the heater 20 along the output end i. The flow rate of the heat source working medium required to be injected can be calculated according to the following formula:

[0083] ;

[0084] wherein, is the working medium flow rate injected into the phase change energy storage array after the demand change and again stable, i.e., the CO2 working medium at the maximum flow rate of the phase change energy storage array 18, which can be directly set according to the design parameters of the phase change energy storage array 18, is the working medium flow rate injected into the heater after the demand change and again stable, is the working medium flow rate of the injected working medium three-way valve, which can be directly measured by the flow meter arranged at the input end of the working medium three-way valve, is the heat source enthalpy output by the heater before the demand change, which can be directly calculated by monitoring the temperature and pressure of the output heat source at the output end j of the heater 20 and using existing enthalpy calculation software according to the measured temperature data and pressure data, The enthalpy value of the working medium outputted by the heater before the demand changes, The enthalpy value of the heat source injected into the heater before the demand changes, can be calculated by monitoring the temperature and pressure of the working medium at the input end ai and the output end ah of the heater.

[0085] After the flow rate injected into the heater 20 is calculated, the flow rate inputted into the temperature control machine 21 can be adjusted, and the flow rate of the heat source working medium injected into the heater 20 can be increased to meet the power demand of the external power grid.

[0086] The above examples are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions described in the foregoing examples can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the description of the present application.

Claims

1. A transcritical CO2 cycle power generation system characterized by comprising: The application relates to a transcritical CO2 cycle system, which comprises a working medium inlet and a working medium outlet; a turbine generator comprising a working medium injection inlet and a working medium discharge outlet, the working medium discharge outlet being connected to the working medium inlet, the turbine generator being connected to an external power grid via a low-voltage power grid; a heat exchange system comprising a working medium three-way valve, the inlet end of the working medium three-way valve being connected to the working medium outlet, and the two outlet ends being connected to the working medium injection inlet via a heater and a phase change energy storage array respectively; and a temperature control machine provided with a heat source inlet and a heat source outlet, the heat source outlet being connected to the heat source inlet end of the phase change energy storage array and the heater via a heat source three-way valve; wherein the working medium three-way valve and the heat source three-way valve are respectively configured to adjust the heat source flow and the working medium flow injected into the phase change energy storage array and the heater according to the power demand of the external power grid. The transcritical CO2 cycle system comprises: a vortex tube comprising a CO2 working medium inlet, a CO2 saturated liquid outlet, a CO2 saturated vapor outlet and a CO2 superheated steam outlet, the CO2 working medium inlet being connected to the working medium inlet; a liquid mixer comprising two liquid inlets and a liquid outlet, one of the liquid inlets being connected to the CO2 saturated liquid outlet, and the liquid outlet being connected to the working medium outlet; a gas mixer comprising two gas inlets and a gas outlet, the two gas inlets being connected to the CO2 saturated vapor outlet and the CO2 superheated steam outlet respectively; and a compressor comprising a gas inlet and a liquid outlet, the gas inlet being connected to the gas outlet, and the liquid outlet being connected to the other liquid inlet. The transcritical CO2 cycle system further comprises: a pre-cooler, the two ends of the pre-cooler being connected to the CO2 working medium inlet and the working medium inlet respectively. The transcritical CO2 cycle system further comprises: a high-temperature regenerator comprising two high-temperature heat exchange pipes, one of the high-temperature heat exchange pipes being connected to the liquid outlet and the working medium outlet, and the other high-temperature heat exchange pipe being connected to the pre-cooler and the working medium inlet. The transcritical CO2 cycle system further comprises: a low-temperature regenerator comprising two low-temperature heat exchange pipes, one of the low-temperature heat exchange pipes being connected to the CO2 saturated liquid outlet and the liquid inlet, and the other low-temperature heat exchange pipe being connected to the high-temperature heat exchange pipe and the pre-cooler. The transcritical CO2 cycle system further comprises: a booster pump connected to the CO2 saturated liquid outlet and the low-temperature heat exchange pipe. The transcritical CO2 cycle system further comprises: a heat-consuming device, the low-temperature heat exchange pipe being connected to the pre-cooler via the heat-consuming device. The low-voltage power grid is electrically connected to the temperature control machine, the compressor and the booster pump respectively. The adjustment of the heat source flow and the working medium flow injected into the phase change energy storage array and the heater according to the power demand of the external power grid comprises: when the power demand of the external power grid is at a low load, the heat source flow injected into the phase change energy storage array and the heater is determined according to the following calculation formula: when the power demand of the external power grid is at a high load, the heat source flow injected into the heater is determined according to the following calculation formula: ​ ​ ​ ​ 2. The transcritical CO2 cycle power generation system according to claim 1, characterized by, ​ 3. The transcritical CO2 cycle power generation system according to claim 2, characterized by, ​ 4. The transcritical CO2 cycle power generation system according to claim 3, characterized by, ​ 5. The transcritical CO2 cycle power generation system according to claim 3, characterized by, ​ 6. The transcritical CO2 cycle power generation system according to claim 4, characterized by, ​ 7. The transcritical CO2 cycle power generation system of claim 1, wherein, ​ ​ ； ； wherein, is the heat source flow rate injected into the heater before the demand change, is the heat source enthalpy injected into the heater before the demand change, is the heat source flow rate output by the temperature control machine before the demand change, is the heat source flow rate injected into the temperature control machine before the demand change, is the heat source enthalpy output by the temperature control machine before the demand change, is the heat source enthalpy injected into the heater after the demand change and the new stability, is the heat source flow rate injected into the heater after the demand change and the new stability, is the heat source flow rate injected into the phase change energy storage array after the demand change and the new stability. ​ ； wherein, is the mass flow rate of the working fluid injected into the phase change thermal energy storage array after the demand has changed and stabilized again, is the mass flow rate of the working fluid injected into the heater after the demand has changed and stabilized again, is the mass flow rate of the working fluid injected into the three-way valve, is the heat source enthalpy output from the heater before the demand has changed, is the working fluid enthalpy output from the heater before the demand has changed, is the heat source enthalpy injected into the heater before the demand has changed.

Images