A coupled thermodynamic cycle system

Abstract

The present invention discloses a coupled thermodynamic cycle system, which relates to the technical field of energy utilization. By inputting the expanded first working fluid and the deaerated second working fluid into the heat exchanger module for heat exchange, the coupling of the organic Rankine cycle module and the Brayton cycle module in the application of the heat source of the fusion reactor is effectively realized. On the one hand, the temperature of the first working fluid can be reduced through heat transfer to reduce the cooling cost of the first working fluid. On the other hand, the heat in the Brayton cycle module can be utilized to reduce the generation of waste heat. In addition, the organic Rankine cycle module has a reheating stage, which can effectively improve the energy conversion efficiency of the coupled thermodynamic cycle system. Moreover, setting the parameters of the coupled thermodynamic cycle system based on enthalpy values can further improve the system thermal efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of energy utilization, and particularly to a coupled thermodynamic cycle system. Background Art

[0002] Compared with non-dispatchable renewable energy sources such as wind energy and photovoltaic power generation, fusion energy has the prospect of large-scale power generation because its fuel is almost inexhaustible and it is a dispatchable energy source.

[0003] During the power generation process, the thermodynamic cycle is the bridge connecting heat energy and electrical energy. A reasonable thermodynamic cycle can effectively improve the energy utilization efficiency. However, the heat generated by the fusion reactor is accompanied by a high-temperature and high-pressure environment, and there is still a large amount of waste heat that is not utilized when the existing thermodynamic cycle is applied to the fusion reactor, which severely restricts the wide application and development of fusion energy as a power generation energy source. Summary of the Invention

[0004] The purpose of the embodiments of the present invention is to provide a coupled thermodynamic cycle system, which can make full use of the heat energy of the fusion reactor and the low-grade waste heat generated during the power generation process by coupling the Brayton cycle and the organic Rankine cycle, reduce the waste heat generated by the entire system, and has good thermal performance.

[0005] The embodiments of the present invention provide a coupled thermodynamic cycle system, including a Brayton cycle module, a heat exchanger module, and an organic Rankine cycle module with a reheat stage; the heat exchanger module includes a first channel and a second channel;

[0006] The working fluid of the Brayton cycle module is a first working fluid, and the working fluid of the organic Rankine cycle module is an organic second working fluid; the parameters of the coupled thermodynamic cycle system are set according to the enthalpy changes of the first working fluid and the second working fluid;

[0007] The Brayton cycle module is connected to a heat source and is used to convert the heat energy transmitted by the heat source into first electric energy; the first channel inhales the first working fluid expanded by the Brayton cycle module at the inlet, the second channel inhales the second working fluid deaerated by the organic Rankine cycle module at the inlet, and the outlets of the first channel and the second channel respectively return the heat-exchanged first working fluid and second working fluid to the Brayton cycle module and the organic Rankine cycle module; the organic Rankine cycle module is used to convert the heat energy transmitted by the heat exchanger module into second electric energy.

[0008] As an improvement of the above solution, the first working fluid is supercritical carbon dioxide, and the second working fluid is R245fa.

[0009] As an improvement of the above solution, the Brayton cycle module includes a first turbine unit, a regenerator, a cooler unit, a compressor unit, and a first generator;

[0010] The heat source is connected to the inlet of the first turbine unit. The outlet of the first turbine unit is connected to the inlet of the regenerator, the first generator, and the inlet of the first channel. The first outlet of the regenerator is connected to the heat source. The second outlet of the regenerator is connected to the inlet of the compressor unit through a cooler unit. The outlet of the compressor unit is connected to the inlet of the regenerator and the first turbine unit.

[0011] As an improvement to the above solution, the first working fluid sequentially passes through the compressor unit, the first turbine unit, the regenerator, the cooler unit, and then is introduced into the compressor unit to form a cycle; the first working fluid output from the outlet of the first channel sequentially passes through the regenerator and the cooler unit and is introduced into the compressor unit.

[0012] As an improvement to the above solution, the compressor unit includes a cooler and a number of compressors connected in sequence, and a cooler is also provided between adjacent compressors.

[0013] As an improvement to the above solution, the first turbine unit includes a first high-pressure turbine and a first low-pressure turbine connected in sequence. The inlet of the first high-pressure turbine is the inlet of the first turbine unit, and the outlet of the first low-pressure turbine is the outlet of the first turbine unit.

[0014] As an improvement to the above solution, the organic Rankine cycle module includes a second turbine unit, a reheater, a condenser, a deaerator, a mixer unit, a steam extraction pipeline unit, and a second generator;

[0015] The second turbine unit includes a second high-pressure turbine and a second low-pressure turbine. The mixer unit includes a first mixer, a second mixer, and a third mixer. The steam extraction pipeline unit includes a first steam extraction pipeline, a second steam extraction pipeline, and a third steam extraction pipeline;

[0016] The outlet of the second channel is connected to the inlet of the second high-pressure turbine. The outlet of the second high-pressure turbine is connected to the inlet of the second low-pressure turbine and the inlet of the reheater. The outlet of the reheater is connected to the inlet of the second low-pressure turbine. The outlet of the second low-pressure turbine is connected to the second generator and the inlet of the condenser. The outlet of the condenser is connected to the inlet of the first mixer. The outlet of the first mixer is connected to the second mixer. The outlet of the second mixer is connected to the inlet of the first mixer, and the outlet of the second mixer is connected to the inlet of the deaerator. The outlet of the deaerator is connected to the inlet of the third mixer. The outlet of the third mixer is connected to the inlet of the deaerator and the inlet of the second channel; the first steam extraction pipeline connects the second high-pressure turbine to the third mixer and the reheater; the second steam extraction pipeline connects the second low-pressure turbine to the first mixer; the third steam extraction pipeline connects the second low-pressure turbine to the second mixer.

[0017] As an improvement of the above solution, the second working fluid sequentially passes through a deaerator, a third mixer, a heat exchanger module, a second high-pressure turbine, a reheater, a second low-pressure turbine, a condenser, a first mixer and a second mixer, and then is introduced into the deaerator to form a cycle; the second working fluid also enters the third mixer and the reheater through the second high-pressure turbine; the second working fluid also enters the first mixer and the second mixer respectively through the second low-pressure turbine.

[0018] As an improvement of the above solution, the organic Rankine cycle module further includes a power unit, and the power unit includes a first pump and a second pump; the second working fluid enters the organic Rankine cycle module through the power unit;

[0019] The first pump is arranged between the outlet of the condenser and the inlet of the first mixer, and the second pump is arranged between the outlet of the deaerator and the inlet of the third mixer.

[0020] As an improvement of the above solution, the organic Rankine cycle module further includes a valve unit, and the valve unit includes a first valve, a second valve, a third valve and a fourth valve;

[0021] The first valve is arranged between the outlet of the second channel and the inlet of the second high-pressure turbine, and the second valve is arranged between the outlet of the second mixer and the inlet of the first mixer; the third valve is arranged between the outlet of the third mixer and the inlet of the deaerator; the fourth valve is arranged between the outlet of the third mixer and the inlet of the second channel.

[0022] Compared with the prior art, a coupled thermal power cycle system disclosed by the present invention effectively realizes the coupling of the organic Rankine cycle module and the Brayton cycle module by inputting the expanded first working fluid and the deaerated second working fluid into the heat exchanger module for heat exchange. On the one hand, it can reduce the temperature of the first working fluid through heat transfer to reduce the cooling cost of the first working fluid, and on the other hand, it can also utilize the heat in the Brayton cycle module to reduce the generation of waste heat. In addition, the organic Rankine cycle has a reheating stage, which can effectively improve the energy conversion efficiency of the coupled thermal power cycle system. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of a coupled thermal power cycle system provided by an embodiment of the present invention;

[0024] Figure 2 is a schematic structural diagram of a Brayton cycle module provided by an embodiment of the present invention;

[0025] Figure 3 is a schematic structural diagram of another Brayton cycle module provided by an embodiment of the present invention;

[0026] Figure 4 is a schematic structural diagram of an organic Rankine cycle provided by an embodiment of the present invention. Detailed implementation manners

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the description of the specification and claims, it should be understood that the terms first, second, etc. in the specification and claims are only used for the purpose of distinguishing the description of the same technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features, nor necessarily describing the order or time sequence. The terms can be interchanged under appropriate circumstances. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features.

[0029] Since the fusion reactor has the characteristics of high temperature and high pressure, when using it for energy conversion and power generation, the Brayton cycle or the Rankine cycle is usually adopted. However, the problems existing in the prior art at least lie in that neither the Brayton cycle nor the Rankine cycle can make good use of low-grade waste heat, resulting in low thermal energy utilization efficiency during the power generation process and causing a large amount of losses.

[0030] Based on the above considerations, the embodiments of the present invention provide a coupled thermodynamic cycle system. Please refer to Figure 1 , in this embodiment, the coupled thermodynamic cycle system includes a Brayton cycle module 1, a heat exchanger module 2, and an organic Rankine cycle module 3 with a reheat stage; the heat exchanger module includes a first channel and a second channel;

[0031] The working fluid of the Brayton cycle module 1 is the first working fluid, and the working fluid of the organic Rankine cycle module 3 is the organic second working fluid; the parameters of the coupled thermodynamic cycle system are set according to the enthalpy change of the first working fluid and the second working fluid;

[0032] The Brayton cycle module 1 is connected to a heat source and is used to convert the thermal energy transferred by the heat source into the first electric energy; the first channel inhales the first working fluid expanded by the Brayton cycle module at the inlet, and the second channel inhales the second working fluid deaerated by the organic Rankine cycle module 3 at the inlet. The outlets of the first channel and the second channel respectively return the heat-exchanged first working fluid and second working fluid to the Brayton cycle module 1 and the organic Rankine cycle module 3; the organic Rankine cycle module 3 is used to convert the thermal energy transferred by the heat exchanger module 2 into the second electric energy.

[0033] The Brayton cycle module can perform energy cycle conversion on the thermal energy generated by a fusion reactor in a high-temperature and high-pressure environment to generate electrical energy. However, it can be understood that during the operation of a traditional Brayton cycle, the working fluid needs to be cooled, and a large amount of thermal energy will be lost during the cooling process, greatly reducing the utilization efficiency of thermal energy.

[0034] In the embodiment of the present invention, the expanded first working fluid and the deoxygenated second working fluid are input into the heat exchanger module for heat exchange, effectively realizing the coupling of the organic Rankine cycle module and the Brayton cycle module in the application of the heat source of the fusion reactor. On the one hand, it can reduce the temperature of the first working fluid through heat transfer to reduce the cooling cost of the first working fluid. On the other hand, it can also utilize the heat in the Brayton cycle module to reduce the generation of waste heat. In addition, the organic Rankine cycle module has a reheating stage, which can effectively improve the energy conversion efficiency of the coupled thermodynamic cycle system. The parameters of the coupled thermodynamic cycle system are set based on enthalpy values, which can further improve the system thermal efficiency.

[0035] The traditional Rankine cycle uses water as the working fluid. Its thermodynamic cycle is that water is heated into high-temperature and high-pressure steam in a boiler, and the steam enters a steam turbine to expand and do work, driving the rotation of the steam turbine rotor, thereby driving a generator to generate electricity. The exhausted steam after doing work enters a condenser, is cooled and condensed into water, and then is sent back to the boiler by a feed pump to complete a cycle. However, it can be understood that since water cannot evaporate at a low temperature, it is not suitable for heat sources in the low-temperature range. In the organic Rankine cycle module described in the embodiment of the present invention, an organic second working fluid is used, which can perform energy conversion on low-grade waste heat.

[0036] It should also be noted that as the service life of the traditional heat exchanger module increases, temperature slip may occur, which will further lead to a reduction in the thermal efficiency of the thermodynamic cycle system. Considering that it is difficult to efficiently match the temperature curves of the organic Rankine cycle module and the Brayton cycle in the prior art, the embodiment of the present invention proposes to set the parameters of the coupled thermodynamic cycle system according to the enthalpy change of the first working fluid and the second working fluid. Exemplarily, the organic Rankine cycle module includes a pump for pumping the second working fluid. The power of the pump is calculated according to the mass and enthalpy value changes of the second working fluid under the pump connection line. Setting the parameters of the coupled thermodynamic cycle system through the enthalpy change situation can improve the system thermal efficiency and avoid an increase in exergy loss.

[0037] As a preferred embodiment, the first working fluid is supercritical carbon dioxide, and the second working fluid is R245fa.

[0038] It should be noted that the Brayton cycle module with supercritical carbon dioxide as the working fluid usually operates at 500 - 700 °C, and the organic Rankine cycle module with R245fa as the working fluid usually operates under temperature conditions below 200 °C.

[0039] In the embodiments of the present invention, water, toluene, and R245fa are respectively selected as the secondary working fluid for the thermal performance analysis of the system, and the analysis is shown in Table 1.

[0040] Table 1 Thermal performance corresponding to different secondary working fluids

[0041]

[0042] It can be seen that compared with water or toluene, R245fa can operate at a lower pressure and has a lower boiling point. In the embodiments of the present invention, considering the operating conditions of the organic Rankine cycle module in the coupled thermodynamic cycle system, R245fa is preferably used as the secondary working fluid.

[0043] As a preferred embodiment, please refer to Figure 2 , the Brayton cycle module 1 includes a first turbine unit 11, a recuperator 12, a cooler unit 13, a compressor unit 14, and a first generator 15;

[0044] The heat source is connected to the inlet of the first turbine unit 11. The outlet of the first turbine unit 11 is connected to the inlet of the recuperator 12, the first generator 15, and the inlet of the first channel. The first outlet of the recuperator 12 is connected to the heat source. The second outlet of the recuperator 12 is connected to the inlet of the compressor unit 14 through the cooler unit 13. The outlet of the compressor unit 14 is connected to the inlets of the recuperator 12 and the first turbine unit 11.

[0045] In the above solution, the first turbine unit 11 expands and does work using the heat source, converts thermal energy into mechanical energy, and drives the first generator 15 to generate electricity to achieve energy conversion. The recuperator 12 recovers the waste heat from the first turbine unit 11, inputs a part of the remaining heat into the compressor unit 14, and sends another part of the remaining heat back to the heat source for reheating, improving the thermal efficiency of the entire cycle. The cooler unit 13 ensures the normal operation of the compressor unit 14 by cooling. The compressor unit 14 increases energy through work to prepare for subsequent expansion and work. By adopting the Brayton cycle module 1 described in the embodiments of the present invention, the processes of expansion and work, waste heat recovery, cooling, and compression can be continuously repeated to form a continuous cycle and continuously achieve energy conversion and power generation.

[0046] The embodiments of the present invention give the structural schematic diagrams of the Brayton cycle module as shown in Figure 2 and Figure 3 . It should be noted that Figure 2 and Figure 3 The dashed parts are the flow paths of the first working fluid, and the first working fluid circulates in the Brayton cycle module.

[0047] In some preferred embodiments of the present invention, the temperature and / or pressure at each node in the Brayton cycle module are pre-selected to accurately set the specific parameters of the coupled thermodynamic cycle system. The selected temperature and / or pressure are required to meet the operating temperature and / or pressure of the Brayton cycle module and the organic Rankine cycle module.

[0048] Exemplarily, the pre-selected temperatures include the outlet temperature of the first turbine unit being 270 °C, the inlet temperature of the regenerator being 210 °C, the outlet temperature of the regenerator being 130 °C, the pressure being 8.65 MPa, the thermal power being 300 kW, and the inlet temperature of the compressor unit being 32 °C. Based on the set temperature and / or pressure, the initial enthalpy change is obtained for parameter design.

[0049] Further, preferably, the first working fluid sequentially passes through the compressor unit 14, the first turbine unit 11, the regenerator 12, the cooler unit 13, and then enters the compressor unit 14 to form a cycle; the first working fluid output from the outlet of the first channel sequentially passes through the regenerator 12 and the cooler unit 13 and enters the compressor unit 14.

[0050] In the embodiments of the present invention, the first working fluid flows orderly between different components, making the energy distribution of the system more flexible.

[0051] Preferably, referring to Figure 3 , the compressor unit 14 includes a cooler and a plurality of compressors connected in sequence, and a cooler is also provided between adjacent compressors.

[0052] Further, in some preferred embodiments, the compressor includes a first compressor 141, a second compressor 142, and a third compressor 143 connected in sequence, and the cooler includes a first cooler 144 and a second cooler 145. Among them, the first cooler 144 is provided between the first compressor 141 and the second compressor 142, and the second cooler 145 is provided between the second compressor 142 and the third compressor 143. The inlet of the first compressor 141 is the inlet of the compressor unit 14, and the outlet of the third compressor 143 is the outlet of the compressor unit 14.

[0053] By providing a cooler between adjacent compressors, the temperature after each stage of compression can be reduced, the irreversible loss during the compression process can be reduced, and the compression efficiency can be improved. And the multi-stage compressor can flexibly adjust the compression ratio and flow rate according to different working conditions.

[0054] It should be noted that in the embodiments of the present invention, there are two flow paths between adjacent compressors, namely the flow path directly from the upper-stage compressor to the lower-stage compressor, and the flow path from the upper-stage compressor through the cooler to the lower-stage compressor. In the embodiments of the present invention Figure 3Among them, different circuits are represented by solid lines and dashed lines. In actual operation, both the solid line and the dashed line correspond to real physical connection relationships.

[0055] Preferably, the first turbine unit 11 includes a first high-pressure turbine 111 and a first low-pressure turbine 112 connected in sequence. The inlet of the first high-pressure turbine 111 is the inlet of the first turbine unit 11, and the outlet of the first low-pressure turbine 112 is the outlet of the first turbine unit 11.

[0056] By expanding and doing work in two stages, the first working fluid can expand and do work gradually at different pressure stages, making full use of the energy of the high-temperature and high-pressure working fluid, and converting heat energy into mechanical energy more efficiently.

[0057] As a preferred implementation, please refer to Figure 4 , the organic Rankine cycle module 3 includes a second turbine unit, a reheater 32, a condenser 33, a deaerator 34, a mixer unit, a steam extraction pipeline unit, and a second generator 37;

[0058] The second turbine unit includes a second high-pressure turbine 311 and a second low-pressure turbine 312. The mixer unit includes a first mixer 351, a second mixer 352, and a third mixer 353. The steam extraction pipeline unit includes a first steam extraction pipeline 361, a second steam extraction pipeline 362, and a third steam extraction pipeline 363;

[0059] The outlet of the second channel is connected to the inlet of the second high-pressure turbine 311. The outlet of the second high-pressure turbine 311 is connected to the inlet of the second low-pressure turbine 312 and the inlet of the reheater 32. The outlet of the reheater 32 is connected to the inlet of the second low-pressure turbine 312. The outlet of the second low-pressure turbine 312 is connected to the second generator 37 and the inlet of the condenser 33. The outlet of the condenser 33 is connected to the inlet of the first mixer 351. The outlet of the first mixer 351 is connected to the second mixer 352. The outlet of the second mixer 352 is connected to the inlet of the first mixer 351, and the outlet of the second mixer 352 is connected to the inlet of the deaerator 34. The outlet of the deaerator 34 is connected to the inlet of the third mixer 353. The outlet of the third mixer 353 is connected to the inlet of the deaerator 34 and the inlet of the second channel; The first steam extraction pipeline 361 connects the second high-pressure turbine 311 with the third mixer 353 and the reheater 32; The second steam extraction pipeline 362 connects the second low-pressure turbine 312 with the first mixer 351; The third steam extraction pipeline 363 connects the second low-pressure turbine 312 with the second mixer 352.

[0060] It should be noted that different reheating and steam extraction settings of the organic Rankine cycle module will greatly affect the thermal performance of the system. Moreover, even if the reheating stage is the same, the regenerative configuration and position of the high-pressure / low-pressure turbines will also change the thermal performance of the power conversion system.

[0061] In the above preferred embodiment of the present invention, the organic Rankine cycle module realizes two-stage expansion through the second high-pressure turbine and the second low-pressure turbine, and a reheater is equipped between the two-stage expansions, which can effectively improve the quality of the second working fluid, and increase the temperature of the second working fluid entering the second low-pressure turbine, so that the enthalpy drop of the second working fluid expanding and doing work in the second low-pressure turbine increases, so as to improve the mechanical work output and energy utilization efficiency.

[0062] It should also be noted that water is used as the second working fluid in the traditional Rankine cycle module, and a steam-water separator also needs to be configured in the system, which reduces the energy conversion efficiency. However, the organic second working fluid adopted in the solution of the present application does not contain moisture or water droplets, so there is no need to equip a steam-water separator.

[0063] In addition, the extraction pipeline unit set as in the embodiment of the present invention can effectively optimize the organic Rankine cycle module.

[0064] There are three extractions in the organic Rankine cycle module. The first extraction draws the second working fluid out of the second high-pressure turbine and enters the third mixer and the reheater to realize the stepped utilization of energy. The second extraction and the third extraction draw the second working fluid out of the second low-pressure turbine and enter the second mixer and the third mixer respectively, which can flexibly adjust the load and balance the pressure and temperature of the organic Rankine cycle module.

[0065] In the embodiment of the present invention, preferably, the second working fluid sequentially passes through the deaerator 34, the third mixer 353, the heat exchanger module 2, the second high-pressure turbine 311, the reheater 32, the second low-pressure turbine 312, the condenser 33, the first mixer 351 and the second mixer 352, and then is introduced into the deaerator 34 to form a cycle; the second working fluid also enters the third mixer 353 and the reheater 32 through the second high-pressure turbine 311; the second working fluid also enters the first mixer 351 and the second mixer 352 respectively through the second low-pressure turbine 312.

[0066] Preferably, the organic Rankine cycle module 3 further includes a power unit, and the power unit includes a first pump 381 and a second pump 382; the second working fluid enters the organic Rankine cycle module 3 through the power unit;

[0067] The first pump 381 is arranged between the outlet of the condenser 33 and the inlet of the first mixer 351, and the second pump 382 is arranged between the outlet of the deaerator 34 and the inlet of the third mixer 353.

[0068] It should be noted that the setting of the power unit can ensure the continuous circulation of the secondary working fluid in the system and realize the continuous conversion of energy. The first pump is arranged near the condenser, which can enable the liquid working fluid discharged from the condenser to be sucked into the pump with the shortest distance and the least resistance. The pipeline resistance loss is reduced, the energy consumption of the pump is lowered, and the system efficiency is improved. In the embodiment of the present invention, the position of the pump in the power unit can meet the flow requirements of the secondary working fluid, and the layout of the organic Rankine cycle module and the equipment installation space are fully considered.

[0069] In some preferred embodiments, the secondary working fluid enters the organic Rankine cycle module through the power unit. It should be noted that, for the sake of utilization rate and energy conservation, not every pump of the power unit extracts the secondary working fluid from the outside to enter the cycle, and only some pumps can be selected as the working fluid inlets.

[0070] In some other preferred embodiments, it is also possible to pre-fill the secondary working fluid in the organic Rankine cycle module and utilize the existing secondary working fluid in the cycle for heat energy conversion during operation.

[0071] Preferably, the organic Rankine cycle module further includes a valve unit, and the valve unit includes a first valve 391, a second valve 392, a third valve 393, and a fourth valve 394;

[0072] The first valve 391 is arranged between the outlet of the second channel and the inlet of the second high-pressure turbine 311, and the second valve 392 is arranged between the outlet of the second mixer 352 and the inlet of the first mixer 351; the third valve 393 is arranged between the outlet of the third mixer 353 and the inlet of the deaerator 34; the fourth valve 394 is arranged between the outlet of the third mixer 353 and the inlet of the second channel.

[0073] By adjusting the opening degrees of the valves in the valve unit, the flow rate of the secondary working fluid between the various components of the system can be accurately controlled, and the pressures of the various components can be maintained within a preset range. The setting of the valve parameters needs to be combined with the design pressure and safety requirements of the organic Rankine cycle module to ensure that the system can perform timely and effective safety protection.

[0074] It should be noted that in the preferred embodiment of the present invention, the secondary working fluid flows out of the second mixer 352, flows through the second valve 392 to the first mixer 351, and is mixed with the secondary working fluid extracted from the second extraction steam pipeline 362, and then enters the deaerator 34 through the second mixer 352 again.

[0075] It is understandable that the parameter design of the coupled thermodynamic cycle system is as important as the architecture design. In the above embodiments, it has been illustrated that in the present invention, the parameters of the coupled thermodynamic cycle system are set according to the enthalpy changes of the first working fluid and the second working fluid. More specifically, it is set according to the enthalpy changes of the first working fluid and the second working fluid before and after passing through each component. In this process, the change in the heat capacity flow rate will be fully considered to avoid the problem of reduced thermal efficiency caused by temperature slip in the heat exchanger module.

[0076] To better understand and implement the embodiments of the present invention, the following will give a configuration method for a coupled thermodynamic cycle system in combination with the system structure shown in the drawings of the present invention.

[0077] An embodiment of the present invention provides a configuration method for a coupled thermodynamic cycle system, which is applied to the above-mentioned coupled thermodynamic cycle system. The configuration method includes:

[0078] According to the structure of the coupled thermodynamic cycle system and the selection of the working fluid, perform thermodynamic modeling to obtain a thermodynamic simulation model;

[0079] In the thermodynamic simulation model, based on the thermodynamic performance, calculate the enthalpy change of the working fluid when passing through each component to obtain the performance indexes of each component; the performance indexes include power and efficiency;

[0080] According to the performance indexes, perform preliminary configuration and verification on the thermodynamic simulation model to obtain a verification result;

[0081] According to the verification result, generate an optimized configuration plan, and use the optimized configuration plan to configure the coupled thermodynamic cycle system.

[0082] In the process of establishing and solving the thermodynamic simulation model, the law of conservation of mass, the law of conservation of energy, and the laws of thermodynamics need to be followed. The embodiments of the present invention also take into account the change in enthalpy value.

[0083] In some preferred embodiments, according to the law of conservation of mass, it can be obtained that:

[0084] ; ; ;

[0085] Among them, is the mass flow rate of the second working fluid at the inlet of the second high-pressure turbine; is the mass flow rate of the second working fluid extracted by the third mixer from the second high-pressure turbine; is the mass flow rate of the second working fluid at the outlet of the second high-pressure turbine; is the mass flow rate of the second working fluid lost in the reheater; is the mass flow rate of the second working fluid at the outlet of the reheater; The mass flow rate of the second working fluid extracted from the second low-pressure turbine by the second mixer; The mass flow rate of the second working fluid extracted from the second low-pressure turbine by the first mixer; The mass flow rate of the second working fluid at the outlet of the second low-pressure turbine.

[0086] In the embodiments configured with the steam extraction pipeline / steam extraction point, it is necessary to set the pressure and temperature of the steam extraction pipeline / steam extraction point, and the selection is based on the requirement of the outlet temperature.

[0087] In the embodiments of the present invention, the first steam extraction pipeline is connected to the outlet of the second high-pressure turbine, and the flow direction of the second working fluid in the first steam extraction pipeline is from the second high-pressure turbine to the third mixer. In practical applications, generally, a first steam extraction point is set on the third mixer, and the first steam extraction point is connected to the first steam extraction pipeline to achieve the steam extraction operation. The parameter design of the steam extraction point is very important, which will affect the energy distribution and regeneration efficiency of the system. By controlling the fluid mass of the first steam extraction pipeline, the system load can be effectively balanced and the stable operation of the system can be ensured.

[0088] In some preferred embodiments, the mass flow rate of the first steam extraction pipeline is expressed as:

[0089] ;

[0090] Wherein, is the mass flow rate of the extracted second working fluid; is the change in enthalpy value before and after steam extraction at the first steam extraction point; is the mass flow rate of the second working fluid at the inlet of the second high-pressure turbine; is the enthalpy value when the second working fluid flows out of the third mixer, is the enthalpy value when the second working fluid flows into the third mixer.

[0091] In the above solution, based on the law of conservation of energy, by solving the mass flow rate at the inlet of the first steam extraction pipeline through the known mass flow rate and enthalpy value parameters, the influence of the change in the heat capacity flow rate on the system parameters can be effectively and fully considered.

[0092] The second steam extraction pipeline is connected to the second low-pressure turbine and the second mixer, and the flow direction of the second working fluid in the second steam extraction pipeline is from the second low-pressure turbine to the second mixer. In practical applications, generally, a second steam extraction point is set on the second mixer, and the second steam extraction point is connected to the second steam extraction pipeline to achieve the steam extraction operation.

[0093] In some preferred embodiments, the mass flow rate of the second steam extraction pipeline is expressed as:

[0094] ;

[0095] wherein, is the mass of the second working fluid at the outlet of the second low-pressure turbine; and are the enthalpy values of the second working fluid at the inlet and outlet of the second mixer respectively; is the mass flow rate of the second working fluid extracted at the second extraction point; is the change in enthalpy before and after extraction at the second extraction point.

[0096] The third extraction pipeline is connected to the second low-pressure turbine and the first mixer, and the flow direction of the second working fluid in the third extraction pipeline is from the second low-pressure turbine to the first mixer. In practical applications, generally a third extraction point is set on the second mixer, and this third extraction point is connected to the third extraction pipeline to achieve the extraction operation.

[0097] In some preferred embodiments, the mass flow rate at the inlet of the third extraction pipeline is expressed as:

[0098] ;

[0099] wherein, is the enthalpy value of the second working fluid at the inlet of the first mixer; is the mass flow rate of the second working fluid extracted at the third extraction point; is the change in enthalpy before and after extraction at the third extraction point.

[0100] When optimizing the model parameters, it is necessary to calculate the efficiency, power, etc. of the system to achieve precise optimization.

[0101] Since losses will inevitably occur during the expansion process of the turbine unit and the compression process of the working fluid by the power unit, the thermal efficiency of the pump is expressed as:

[0102] ;

[0103] wherein, is the actual work done by the pump on the unit mass of the working fluid, including various losses inside the pump; is the isentropic work done assuming the compression process inside the pump is an isentropic process; is the actual enthalpy value of the working fluid at the inlet of the pump; is the ideal enthalpy value at the inlet of the pump during the isentropic process; is the ideal enthalpy value at the outlet of the pump during the isentropic process.

[0104] It can be understood that the power of the pump is also calculated based on the enthalpy values of the second working fluid at its inlet and outlet, and is expressed as:

[0105] ;

[0106] ;

[0107] ;

[0108] wherein, is the total system power; is the power of the second high-pressure turbine; is the power of the second low-pressure turbine; is the conventional loss power; is the pump power; is the efficiency of the second generator; is the heat rate; is the heat consumption of the system; is the mass flow rate of the second working fluid in the system; is the enthalpy loss of the second working fluid.

[0109] In order to enable the condenser to have better thermal performance when condensing the working fluid, the condenser pressure cannot be selected as the saturation pressure. This is because if the condenser pressure is too low, it will increase the humidity of the last-stage turbine, which will reduce the life and efficiency of the turbine. The calculation of the condenser parameters can be expressed as:

[0110] ;

[0111] wherein, is the mass of the second working fluid in the condenser; is the enthalpy value when the steam enters the condenser; is the mass flow rate of the cooling water in the condenser; is the enthalpy value when the cooling water enters the condenser; is the enthalpy value when the steam leaves the condenser; is the enthalpy value when the cooling water leaves the condenser.

[0112] It should be noted that the setting of the reheating stage can also improve the thermal performance of the coupled thermodynamic cycle system.

[0113] It has been verified that in the coupled thermodynamic cycle system described in the embodiments of the present invention, compared with the traditional thermodynamic cycle system for fusion reactors, the isentropic efficiency of the second turbine unit in the organic Rankine cycle module has been increased from 0.85 to 0.92. And with the increase of the isentropic efficiency of the turbine, the net work done by the system has increased from 77.64 kW to 82.23 kW, while the heat extracted by the condenser has decreased from 216.1 kW to 211.5 kW. It can be seen that by adopting the embodiments of the present invention, the thermal performance of the thermodynamic cycle system can be effectively improved in many aspects.

[0114] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above various methods. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc.

[0115] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the technical field, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A coupled thermodynamic cycle system, characterized in that, It includes a Brayton cycle module, a heat exchanger module, and an organic Rankine cycle module with a reheating stage; the heat exchanger module includes a first channel and a second channel; The working fluid of the Brayton cycle module is a first working fluid, and the working fluid of the organic Rankine cycle module is an organic second working fluid; the parameters of the coupled thermodynamic cycle system are set according to the enthalpy changes of the first working fluid and the second working fluid; The Brayton cycle module is connected to a heat source and is used to convert the thermal energy transferred by the heat source into first electric energy; the inlet of the first channel sucks in the first working fluid expanded by the Brayton cycle module, and the inlet of the second channel sucks in the second working fluid deaerated by the organic Rankine cycle module. The outlets of the first channel and the second channel respectively return the heat-exchanged first working fluid and second working fluid to the Brayton cycle module and the organic Rankine cycle module; the organic Rankine cycle module is used to convert the thermal energy transferred by the heat exchanger module into second electric energy; The Brayton cycle module includes a first turbine unit, a regenerator, a cooler unit, a compressor unit, and a first generator; The heat source is connected to the inlet of the first turbine unit. The outlet of the first turbine unit is connected to the inlet of the regenerator, the first generator, and the inlet of the first channel. The first outlet of the regenerator is connected to the heat source, and the second outlet of the regenerator is connected to the inlet of the compressor unit through the cooler unit. The outlet of the compressor unit is connected to the inlet of the regenerator and the first turbine unit; The first turbine unit includes a first high-pressure turbine and a first low-pressure turbine connected in sequence. The inlet of the first high-pressure turbine is the inlet of the first turbine unit, and the outlet of the first low-pressure turbine is the outlet of the first turbine unit; The organic Rankine cycle module includes a second turbine unit, a reheater, a condenser, a deaerator, a mixer unit, a steam extraction pipeline unit, and a second generator; The second turbine unit includes a second high-pressure turbine and a second low-pressure turbine. The mixer unit includes a first mixer, a second mixer, and a third mixer. The steam extraction pipeline unit includes a first steam extraction pipeline, a second steam extraction pipeline, and a third steam extraction pipeline; The outlet of the second channel is connected to the inlet of the second high-pressure turbine. The outlet of the second high-pressure turbine is connected to the inlet of the second low-pressure turbine and the inlet of the reheater. The outlet of the reheater is connected to the inlet of the second low-pressure turbine. The outlet of the second low-pressure turbine is connected to the second generator and the inlet of the condenser. The outlet of the condenser is connected to the inlet of the first mixer. The outlet of the first mixer is connected to the second mixer. The outlet of the second mixer is connected to the inlet of the first mixer, and the outlet of the second mixer is connected to the inlet of the deaerator. The outlet of the deaerator is connected to the inlet of the third mixer. The outlet of the third mixer is connected to the inlet of the deaerator and the inlet of the second channel; the first steam extraction pipeline connects the second high-pressure turbine to the third mixer and the reheater; the second steam extraction pipeline connects the second low-pressure turbine to the first mixer; the third steam extraction pipeline connects the second low-pressure turbine to the second mixer.

2. The coupled thermodynamic cycle system according to claim 1, wherein The first working fluid is supercritical carbon dioxide, and the second working fluid is R245fa.

3. A coupled thermodynamic cycle system according to claim 1, wherein, The first working fluid sequentially passes through a compressor unit, a first turbine unit, a recuperator, and a cooler unit, and then is introduced into the compressor unit to form a cycle; the first working fluid output from the outlet of the first channel sequentially passes through the recuperator and the cooler unit and is introduced into the compressor unit.

4. A coupled thermodynamic cycle system according to claim 1, wherein, The compressor unit includes a cooler and a plurality of compressors connected in sequence, and a cooler is also provided between adjacent compressors.

5. A coupled thermodynamic cycle system as claimed in claim 1, wherein The second working fluid sequentially passes through a deaerator, a third mixer, a heat exchanger module, a second high-pressure turbine, a reheater, a second low-pressure turbine, a condenser, a first mixer, and a second mixer, and then is introduced into the deaerator to form a cycle; the second working fluid also enters the third mixer and the reheater through the second high-pressure turbine; the second working fluid also passes through the second low-pressure turbine and is introduced into the first mixer and the second mixer respectively.

6. The coupled thermodynamic cycle system according to claim 1, characterized in that, The organic Rankine cycle module further includes a power unit, and the power unit includes a first pump and a second pump; the second working fluid enters the organic Rankine cycle module through the power unit; The first pump is provided between the outlet of the condenser and the inlet of the first mixer, and the second pump is provided between the outlet of the deaerator and the inlet of the third mixer.

7. A coupled thermodynamic cycle system according to claim 1, wherein, The organic Rankine cycle module further includes a valve unit, and the valve unit includes a first valve, a second valve, a third valve, and a fourth valve; The first valve is provided between the outlet of the second channel and the inlet of the second high-pressure turbine, and the second valve is provided between the outlet of the second mixer and the inlet of the first mixer; the third valve is provided between the outlet of the third mixer and the inlet of the deaerator; the fourth valve is provided between the outlet of the third mixer and the inlet of the second channel.

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