Supercritical carbon dioxide cycle self-adaptive system and adjusting method thereof

Abstract

The invention discloses a supercritical carbon dioxide cycle self-adaptive system and an adjusting method thereof, and belongs to the technical field of power generation systems. The system comprises a supercritical CO2 Brayton cycle subsystem, a working medium adjusting and switching subsystem and a monitoring control subsystem, the working medium adjusting and switching subsystem is selectively communicated with the cycle subsystem through a switchable flow path control unit, and the working medium adjusting and switching subsystem comprises a working medium separation and purification module, a pure component storage tank set and a working medium preparation and injection unit. Separation, purification, storage and proportional injection of a mixed working medium can be achieved, the monitoring control subsystem collects environment temperature and heat source parameters, and a controller automatically determines the type and proportion of a target working medium according to the environment temperature and the heat source parameters, completes working medium switching and dynamically adjusts the flow of the working medium. The problem that in the prior art, working medium types and proportions cannot be rapidly switched according to day and night environment temperature and seasonal fluctuation is solved, separation and recycling of mixed working medium components are achieved, and heat source parameter changes can be rapidly responded.

Description

Technical Field

[0001] This invention relates to the field of power generation system technology, specifically to a supercritical carbon dioxide cycle adaptive system and its regulation method. Background Technology

[0002] Supercritical carbon dioxide (CO2) cycle, as a highly promising and efficient energy conversion technology, owes its advantages primarily to the relatively low critical temperature (304 K) and moderate critical pressure (7.38 MPa) of carbon dioxide (CO2), making it easier to achieve and maintain supercritical operation. In this state, CO2 properties undergo significant abrupt changes, drastically reducing compressor power consumption. However, the critical temperature of CO2 also constitutes a major limitation to its application: in arid, hot regions with scarce water resources, cooling often relies on air cooling, and the high temperature environment can cause the compressor inlet working fluid temperature to be significantly higher than the critical temperature, resulting in compressor inlet conditions far from the near-critical region, a sharp increase in compressor power consumption, and a significant decrease in system cycle efficiency. To overcome these drawbacks, binary mixed working fluids based on CO2, composed of inorganic or organic additives, have attracted widespread attention. By adjusting the composition of the mixture, the critical temperature of the working fluid can be changed, thereby matching it with local climatic conditions and ensuring that the compressor always operates efficiently in the near-critical region. Therefore, CO2-based mixed working fluids have become a research hotspot in many fields such as solar power plants, industrial waste heat recovery, and geothermal power generation.

[0003] However, existing research on CO2 mixed working fluids still has significant shortcomings. First, in actual operating environments using air cooling, a fixed-ratio CO2 mixture cannot effectively cope with diurnal or seasonal temperature variations, making it difficult to maintain the compressor's inlet parameters near the working fluid's critical point. Existing systems lack the ability to quickly switch working fluid types based on ambient temperature changes and to separate and recover the original mixed working fluid in real time. Second, in application scenarios where heat source parameters, such as those in gas turbine waste heat recovery, fluctuate significantly, existing systems lack sufficient adjustment capabilities. In addition to adapting to ambient temperature changes and adjusting the working fluid's critical characteristics, the system should also be able to dynamically adjust the circulating working fluid flow rate based on real-time changes in heat source parameters such as temperature and flow rate to maximize waste heat recovery efficiency and maintain stable system operation.

[0004] Therefore, current technical solutions lack an adaptive regulation system that can quickly switch, separate, and recover mixed working fluid components based on ambient temperature, while simultaneously adjusting the working fluid flow rate in real time according to heat source fluctuations. Summary of the Invention

[0005] The purpose of this invention is to provide a supercritical carbon dioxide cycle adaptive system and its regulation method to overcome the shortcomings of the prior art. It provides an adaptive system and method that can quickly switch the working fluid type and ratio according to changes in ambient temperature, separate and recover mixed working fluid components, and dynamically regulate the working fluid flow rate according to heat source parameters.

[0006] The present invention solves the above-mentioned technical problems through the following technical solution: This invention provides a supercritical carbon dioxide cycle adaptive system, comprising a supercritical CO2 Brayton cycle subsystem, a working fluid regulation and switching subsystem, and a monitoring and control subsystem. The working fluid regulation and switching subsystem is selectively connected to the supercritical CO2 Brayton cycle subsystem via a switchable flow path control unit. The working fluid regulation and switching subsystem includes: a working fluid separation and purification module for separating and purifying the mixed working fluid from the supercritical CO2 Brayton cycle subsystem into single-component working fluids; a pure component storage tank group, connected to the working fluid separation and purification module, for storing the purified single-component working fluids respectively; and a working fluid preparation and injection unit, connected to the pure component storage tank group, for extracting single-component working fluids from the pure component storage tank group and injecting them into the supercritical CO2 Brayton cycle subsystem according to a target ratio. The monitoring and control subsystem includes an ambient temperature sensor, a heat source parameter sensor, and a controller. The controller is signal-connected to the ambient temperature sensor, the heat source parameter sensor, the switchable flow path control unit, the working fluid separation and purification module, the pure component storage tank group, and the working fluid preparation and injection unit.

[0007] A further improvement of the present invention is that the supercritical CO2 Brayton cycle subsystem includes a first cooler, a compressor, a regenerator, a first heater, and a turbine; the switchable flow path control unit includes a first three-way reversing valve and a first shut-off valve; wherein, the outlet of the first cooler is connected to the inlet of the first three-way reversing valve in sequence via the compressor, the heat absorption side of the regenerator, the heat absorption side of the first heater, the turbine, and the heat release side of the regenerator; the first outlet of the first three-way reversing valve is connected to the inlet of the first cooler; the second outlet of the first three-way reversing valve is connected to the inlet of the working fluid regulation and switching subsystem; the outlet of the working fluid regulation and switching subsystem is connected to the inlet of the first cooler via the first shut-off valve.

[0008] A further improvement of the present invention is that the working fluid preparation and injection unit includes a mixer, a first variable frequency working fluid pump, and a second heater. The outlet of the mixer is connected to the heat absorption side inlet of the second heater via the first variable frequency working fluid pump, which is used to pressurize the mixed target working fluid to supercritical pressure. The heat absorption side outlet of the second heater is connected to the first shut-off valve as the outlet of the working fluid regulation and switching subsystem. The heat release side inlet of the second heater is connected to the heat release side outlet of the first heater. A heat source is introduced into the heat release side inlet of the first heater. The heat release side outlet of the second heater is used to output flue gas. The inlet of the mixer is connected to the outlet of the pure component storage tank group.

[0009] A further improvement of the present invention is that the switchable flow path control unit further includes a second three-way reversing valve, the outlet of the first heater heat release side is connected to the inlet of the second three-way reversing valve, the first outlet of the second three-way reversing valve is connected to the inlet of the second heater heat release side; the second outlet of the second three-way reversing valve is used to output flue gas.

[0010] A further improvement of this invention is that the working fluid separation and purification module includes a third three-way reversing valve, a separator, a CO2 purification device, a fourth three-way reversing valve, a fifth three-way reversing valve, a He purification device, a second shut-off valve, an H2S absorption tower, an H2S desorption tower, a second cooler, and a third shut-off valve. Specifically, the inlet of the third three-way reversing valve serves as the inlet of the working fluid regulation and switching subsystem and is connected to the second outlet of the first three-way reversing valve. The first outlet of the third three-way reversing valve is connected to the inlet of the separator. The first outlet of the separator is connected to the inlet of the fifth three-way reversing valve. The first outlet of the fifth three-way reversing valve is connected to the first inlet of the H2S absorption tower. The first outlet of the absorption tower is connected to the inlet of the separator via the third shut-off valve. The second outlet of the separator is connected to the inlet of the CO2 purification device. The first outlet of the CO2 purification unit is connected to the first inlet of the pure component storage tank group. The second outlet of the CO2 purification unit is connected to the inlet of the fourth three-way reversing valve. The first outlet of the fourth three-way reversing valve is connected to the second inlet of the H2S absorption tower. The second outlet of the fourth three-way reversing valve is connected to the inlet of the He purification unit. The first outlet of the He purification unit is connected to the second inlet of the pure component storage tank group. The second outlet of the He purification unit is connected to the inlet of the separator via the second shut-off valve. The second outlet of the fifth three-way reversing valve is connected to the inlet of the He purification unit. The second outlet of the absorption tower is connected to the inlet of the H2S desorption tower. The first outlet of the H2S desorption tower is connected to the third inlet of the pure component storage tank group. The second outlet of the H2S desorption tower is connected to the third inlet of the H2S absorption tower via the second cooler.

[0011] A further improvement of the present invention is that the working fluid separation and purification module also includes a pressure reducing valve and a second variable frequency working fluid pump, the second cooler is connected to the third inlet of the H2S absorption tower via the second variable frequency working fluid pump; the second outlet of the first three-way reversing valve is connected to the inlet of the third three-way reversing valve via the pressure reducing valve.

[0012] A further improvement of this invention is that the pure component storage tank group includes a first regulating valve, a second regulating valve, a third regulating valve, a fourth shut-off valve, a fifth shut-off valve, a sixth shut-off valve, a seventh shut-off valve, a CO2 storage tank, a He storage tank, and an H2S storage tank; wherein, the inlet of the CO2 storage tank serves as the first inlet of the pure component storage tank group and is connected to the outlet of the CO2 purification device sequentially via the fifth shut-off valve and the fourth shut-off valve; the inlet of the He storage tank serves as the second inlet of the pure component storage tank group and is connected to the outlet of the He purification device via the sixth shut-off valve; the inlet of the H2S storage tank serves as the third inlet of the pure component storage tank group and is connected to the outlet of the H2S desorption tower via the seventh shut-off valve; the outlet of the H2S storage tank is connected to the inlet of the mixer via the first regulating valve; the outlet of the He storage tank is connected to the inlet of the mixer via the second regulating valve; and the outlet of the CO2 storage tank is connected to the inlet of the mixer via the third regulating valve.

[0013] This invention also provides an adjustment method for a supercritical carbon dioxide cycle adaptive system. Using the supercritical carbon dioxide cycle adaptive system described above, the method determines the target working fluid type and target ratio based on the ambient temperature detected by an ambient temperature sensor. A controller then controls a switchable flow path control unit, a working fluid separation and purification module, a pure component storage tank group, and a working fluid preparation and injection unit to switch the current working fluid in the supercritical CO2 Brayton cycle subsystem to the target working fluid. Furthermore, based on the heat source temperature and flow rate detected by a heat source parameter sensor, the method adjusts the working fluid flow rate injected into the supercritical CO2 Brayton cycle subsystem by the working fluid preparation and injection unit. When the ambient temperature is below the first temperature threshold, a binary mixture of CO2 and He is selected as the target working medium type; when the ambient temperature is between the first and second temperature thresholds, pure CO2 is selected as the target working medium type; when the ambient temperature is above the second temperature threshold, a binary mixture of CO2 and H2S is selected as the target working medium type.

[0014] A further improvement of the present invention is that when the target working fluid is a binary mixture of CO2 and He or a binary mixture of CO2 and H2S, the target critical temperature is calculated based on the ambient temperature and the preset heat exchange temperature difference, so that the target critical temperature is equal to the ambient temperature plus the preset heat exchange temperature difference, and the target ratio corresponding to the target critical temperature is determined by querying the pre-stored database of working fluid critical temperature and ratio relationship.

[0015] A further improvement of the present invention is that the first temperature threshold is 288K and the second temperature threshold is 298K.

[0016] Compared with the prior art, the positive and progressive effects of the present invention are as follows: The supercritical carbon dioxide cycle adaptive system provided by this invention includes a supercritical CO2 Brayton cycle subsystem, a working fluid regulation and switching subsystem, and a monitoring and control subsystem. The cycle subsystem completes the heating, expansion, reheating, and cooling compression processes of the working fluid. The regulation and switching subsystem is used to separate, purify, and store the working fluid in the cycle, and can mix CO2 with additives (He or H2S) according to a set ratio to form a new supercritical mixed working fluid. The monitoring and control subsystem automatically determines the working fluid type (pure CO2, CO2 / He, or CO2 / H2S) based on the real-time ambient temperature, automatically calculates the additive ratio based on the ambient temperature and the set heat exchange temperature difference, and dynamically adjusts the working fluid circulation flow rate according to the heat source temperature and flow rate. This invention effectively solves the problem in the prior art of failing to quickly switch the type and ratio of working fluid according to the diurnal and seasonal fluctuations of ambient temperature, and realizes the separation and recovery of mixed working fluid components. It can quickly respond to changes in heat source parameters and always operate near the critical point of the working fluid, thereby significantly improving the efficiency and adaptability of the system under wide temperature range and variable load conditions. It is particularly suitable for variable operating conditions such as solar thermal power generation, industrial waste heat recovery and geothermal power generation. Attached Figure Description

[0017] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the structure of a supercritical carbon dioxide cycle adaptive system according to the present invention; Figure 2 Figure (a) shows the relationship between the working fluid ratio and the critical temperature of the working fluid in this invention; Figure (b) shows the relationship between the working fluid He ratio and the critical temperature of the working fluid. Figure 3 This is a flowchart of an adjustment method for a supercritical carbon dioxide cycle adaptive system according to the present invention.

[0019] Among them, 1-1, first cooler; 1-2, compressor; 1-3, regenerator; 1-4, first heater; 1-5, turbine; 1-6, first three-way reversing valve; 1-7, first shut-off valve; 1-8, second three-way reversing valve; 2-1. Pressure reducing valve; 2-2. Third three-way directional valve; 2-3. Separator; 2-4. CO2 purification unit; 2-5. Fourth shut-off valve; 2-6. Fifth shut-off valve; 2-7. CO2 storage tank; 2-8. Fourth three-way directional valve; 2-9. Fifth three-way directional valve; 2-10. He purification unit; 2-11. Sixth shut-off valve; 2-12. He storage tank; 2-13. Second shut-off valve; 2-14. 2-15 H2S Absorption Tower; 2-16 H2S Desorption Tower; 2-17 Seventh Shut-off Valve; 2-18 H2S Storage Tank; 2-19 Second Cooler; 2-10 Second Variable Frequency Working Fluid Pump; 2-21 Third Shut-off Valve; 2-22 First Regulating Valve; 2-23 Third Regulating Valve; 2-24 Mixer; 2-25 First Variable Frequency Working Fluid Pump; 2-26 Second Heater. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This is an explanation of the present invention and not a limitation thereof.

[0025] This invention provides a supercritical carbon dioxide cycle adaptive system, comprising a supercritical CO2 Brayton cycle subsystem, a working fluid regulation and switching subsystem, and a monitoring and control subsystem. The working fluid regulation and switching subsystem is selectively connected to the supercritical CO2 Brayton cycle subsystem via a switchable flow path control unit. The working fluid regulation and switching subsystem includes: a working fluid separation and purification module for separating and purifying the mixed working fluid from the supercritical CO2 Brayton cycle subsystem into single-component working fluids; a pure component storage tank group, connected to the working fluid separation and purification module, for storing the purified single-component working fluids respectively; and a working fluid preparation and injection unit, connected to the pure component storage tank group, for extracting single-component working fluids from the pure component storage tank group and injecting them into the supercritical CO2 Brayton cycle subsystem according to a target ratio. The monitoring and control subsystem includes an ambient temperature sensor, a heat source parameter sensor, and a controller. The controller is signal-connected to the ambient temperature sensor, the heat source parameter sensor, the switchable flow path control unit, the working fluid separation and purification module, the pure component storage tank group, and the working fluid preparation and injection unit.

[0026] The supercritical carbon dioxide cycle adaptive system provided by this invention, through the integration of a monitoring and control subsystem, enables dynamic switching of working fluid type and ratio based on ambient temperature, and real-time adjustment of working fluid flow rate based on heat source parameters, thus solving the problem of system adaptability under changes in ambient temperature and fluctuations in heat source. Specifically, the supercritical CO2 Brayton cycle subsystem serves as the basic cycle framework, providing energy conversion functionality. The working fluid regulation and switching subsystem, through a working fluid separation and purification module, separates the mixed working fluid in the cycle into single components, facilitating recovery and reuse, thus solving the defect of the inability to separate and recover working fluids in real time. Pure component storage tanks store these pure components, providing a resource base for the formulation of new working fluids. The working fluid formulation and injection unit extracts components from the storage tanks according to the target ratio and injects them into the cycle system, achieving rapid working fluid switching to adapt to changes in ambient temperature. The monitoring and control subsystem detects ambient temperature through an ambient temperature sensor and heat source parameter sensors to detect heat source parameters. The controller determines the target working fluid type and ratio based on the ambient temperature, ensuring that the system selects the appropriate working fluid at different temperatures to maintain near-critical operation of compressors 1-2, and achieves seamless working fluid switching through control flow control units, separation and purification modules, etc. Simultaneously, it adjusts the working fluid injection flow rate based on heat source temperature and flow rate to optimize heat source utilization efficiency and respond to heat source fluctuations.

[0027] Preferably, the supercritical CO2 Brayton cycle subsystem includes a first cooler 1-1, a compressor 1-2, a regenerator 1-3, a first heater 1-4, and a turbine 1-5; the switchable flow path control unit includes a first three-way reversing valve 1-6 and a first shut-off valve 1-7; wherein, the outlet of the first cooler 1-1 is connected sequentially to the inlet of the first three-way reversing valve 1-6 via the heat absorption side of the compressor 1-2, the heat absorption side of the regenerator 1-3, the heat absorption side of the first heater 1-4, the turbine 1-5, and the heat release side of the regenerator 1-3; the first outlet of the first three-way reversing valve 1-6 is connected to the inlet of the first cooler 1-1, and the second outlet of the first three-way reversing valve 1-6 is connected to the inlet of the working fluid regulation and switching subsystem; the outlet of the working fluid regulation and switching subsystem is connected to the inlet of the first cooler 1-1 via the first shut-off valve 1-7.

[0028] By specifically defining the components and connection methods of the supercritical CO2 Brayton cycle subsystem and the switchable flow path control unit, flexible flow path control is achieved, ensuring efficient and reliable working fluid switching. The supercritical CO2 Brayton cycle subsystem includes a first cooler 1-1, a compressor 1-2, a regenerator 1-3, a first heater 1-4, and a turbine 1-5. These components work together to achieve the compression, heating, expansion, and cooling cycle of the working fluid, maintaining the supercritical state to improve system efficiency. The switchable flow path control unit includes a first three-way reversing valve 1-6 and a first shut-off valve 1-7. The first three-way reversing valve 1-6 receives the working fluid from the heat release side of the regenerator 1-3 through its inlet, and connects to the inlet of the first cooler 1-1 and the inlet of the working fluid regulation and switching subsystem through its first outlet and second outlet, respectively, to realize flexible switching of the flow path between normal circulation and working fluid regulation. The first shut-off valve 1-7 connects the outlet of the working fluid regulation and switching subsystem and the inlet of the first cooler 1-1 to control the injection of the working fluid back into the circulation system and avoid flow path blockage or pressure fluctuation. The outlet of the first cooler 1-1 passes through the compressor 1-2, the heat absorption side of the regenerator 1-3, the heat absorption side of the first heater 1-4, the turbine 1-5, and the heat release side of the regenerator 1-3 to the inlet of the first three-way reversing valve 1-6, ensuring that the working fluid flow path is continuous and smooth during switching and supporting the system to adaptively adjust the working fluid type according to the ambient temperature.

[0029] Preferably, the working fluid preparation and injection unit includes a mixer 2-24, a first variable frequency working fluid pump 2-25, and a second heater 2-26. The outlet of the mixer 2-24 is connected to the heat absorption side inlet of the second heater 2-26 via the first variable frequency working fluid pump 2-25, which is used to pressurize the mixed target working fluid to supercritical pressure. The heat absorption side outlet of the second heater 2-26 is connected to the first shut-off valve 1-7 as the outlet of the working fluid regulation and switching subsystem. The heat release side inlet of the second heater 2-26 is connected to the heat release side outlet of the first heater 1-4. A heat source is introduced into the heat release side inlet of the first heater 1-4, and the heat release side outlet of the second heater 2-26 is used to output flue gas. The inlet of the mixer 2-24 is connected to the outlet of the pure component storage tank group.

[0030] By optimizing the configuration of the working fluid preparation and injection unit, the problem of insufficient pressurization and heating efficiency of the working fluid under heat source fluctuations is solved. Specifically, mixer 2-24 is used to mix the single-component working fluid in the pure component storage tank according to the target ratio to form the target mixed working fluid; the outlet of mixer 2-24 is connected to the heat absorption side inlet of the second heater 2-26 via the first variable frequency working fluid pump 2-25, and the mixed working fluid is pressurized by the first variable frequency working fluid pump 2-25 to ensure that the working fluid is efficiently boosted to the supercritical pressure, thereby meeting the critical pressure regulation requirements caused by changes in working fluid type or ratio; the heat absorption side outlet of the second heater 2-26 is connected to the first shut-off valve 1-7 as the subsystem outlet to realize the smooth injection of the working fluid into the circulation subsystem; the heat release side inlet of the second heater 2-26 is connected to the first heater 1-4 for heat release. The first heater 1-4 utilizes waste heat from its exhaust to heat the working fluid, reducing additional energy consumption and improving heat source utilization efficiency. The first heater 1-4's ​​heat-exhausting inlet is connected to the heat source, while the second heater 2-26's heat-exhausting outlet is used to output flue gas. This series heating structure maximizes the recovery of heat source energy. The mixer 2-24's inlet connects to the outlet of the pure component storage tank group, ensuring direct access to pure components from the tanks and supporting rapid preparation and switching of the working fluid. The variable frequency characteristic of the first variable frequency working fluid pump 2-25 allows for dynamic adjustment of the working fluid flow rate, and the waste heat integration design of the second heater 2-26 reduces heating energy consumption, collectively enhancing the system's adaptability to changes in heat source parameters.

[0031] Preferably, the switchable flow path control unit further includes a second three-way reversing valve 1-8, the heat release side outlet of the first heater 1-4 is connected to the inlet of the second three-way reversing valve 1-8, the first outlet of the second three-way reversing valve 1-8 is connected to the heat release side inlet of the second heater 2-26, and the second outlet of the second three-way reversing valve 1-8 is used to output flue gas.

[0032] The switchable flow path control unit also includes a second three-way reversing valve 1-8, which provides selectivity for the heat source flow direction, enabling the system to dynamically adjust the path according to the heat source status; the outlet of the first heater 1-4 on the heat release side is connected to the inlet of the second three-way reversing valve 1-8, ensuring that the heat source output can be effectively controlled and preventing the heat source from directly entering the fixed flow path; the first outlet of the second three-way reversing valve 1-8 is connected to the inlet of the second heater 2-26 on the heat release side, allowing the heat source to be used to heat the working fluid when the parameters are suitable, thereby improving the working fluid regulation efficiency; the second outlet of the second three-way reversing valve 1-8 is used to output flue gas, allowing the heat source to be directly discharged when the parameters are mismatched, reducing unnecessary heat loss, thereby optimizing heat source utilization and system stability.

[0033] Preferably, the working fluid separation and purification module includes a third three-way reversing valve 2-2, a separator 2-3, a CO2 purification device 2-4, a fourth three-way reversing valve 2-8, a fifth three-way reversing valve 2-9, a He purification device 2-10, a second shut-off valve 2-13, an H2S absorption tower 2-14, an H2S desorption tower 2-15, a second cooler 2-18, and a third shut-off valve 2-20. The inlet of the third three-way reversing valve 2-2 serves as the inlet of the working fluid regulation and switching subsystem and is connected to the second outlet of the first three-way reversing valve 1-6. The first outlet of the third three-way reversing valve 2-2 is connected to the inlet of the separator 2-3. The first outlet of the separator 2-3 is connected to the inlet of the fifth three-way reversing valve 2-9. The first outlet of the fifth three-way reversing valve 2-9 is connected to the first inlet of the H2S absorption tower 2-14. The first outlet of the absorption tower is connected to the inlet of the separator 2-3 via the third shut-off valve 2-20. The second outlet of the separator 2-3 is connected to the inlet of the CO2 purification device 2-4. The first outlet of the CO2 purification unit 2-4 is connected to the first inlet of the pure component storage tank group. The second outlet of the CO2 purification unit 2-4 is connected to the inlet of the fourth three-way reversing valve 2-8. The first outlet of the fourth three-way reversing valve 2-8 is connected to the second inlet of the H2S absorption tower 2-14. The second outlet of the fourth three-way reversing valve 2-8 is connected to the inlet of the He purification unit 2-10. The first outlet of the He purification unit 2-10 is connected to the second inlet of the pure component storage tank group. The second outlet of the He purification unit 2-10 is connected to the inlet of the separator 2-3 via the second shut-off valve 2-13. The second outlet of the fifth three-way reversing valve 2-9 is connected to the inlet of the He purification unit 2-10. The second outlet of the absorption tower is connected to the inlet of the H2S desorption tower 2-15. The first outlet of the H2S desorption tower 2-15 is connected to the third inlet of the pure component storage tank group. The second outlet of the H2S desorption tower 2-15 is connected to the third inlet of the H2S absorption tower 2-14 via the second cooler 2-18.

[0034] The working fluid separation and purification module integrates multiple dedicated components and flow path control units to achieve separation, purification, and recycling of different components. Specifically, the system inlet is connected to the third three-way reversing valve 2-2, which switches the flow direction according to the monitored input working fluid type: when pure CO2 is input, the working fluid enters the CO2 storage tank 2-7 directly from the second outlet via the fifth shut-off valve 2-6; when mixed working fluid is input, the working fluid enters the separator 2-3 from the first outlet for preliminary separation. The separator 2-3 separates the main components based on differences in physical properties and switches the flow path according to the type of additive. When the additive is H2S, the first outlet of separator 2-3 is connected to H2S absorption tower 2-14 through the fifth three-way reversing valve 2-9 to absorb and purify the H2S component, preventing it from interfering with other components. The second outlet is connected to CO2 purification device 2-4, which is used to purify CO2 and store it directly, ensuring high-purity recovery. The by-product of CO2 purification device 2-4 is controlled by the fourth three-way reversing valve 2-8 and enters H2S absorption tower 2-14 from its first outlet to further absorb residual H2S. The rich liquid after H2S absorption enters H2S desorption tower 2-15 for desorption, obtaining H2S and storing it. The desorbed absorbent is cooled by a cooler and returned to the absorption tower, forming a closed-loop recovery, improving the absorption agent recycling rate and avoiding waste. The unpurified by-product in H2S absorption tower 2-14 is returned from its first outlet to the inlet of separator 2-3 through the third shut-off valve 2-20, repeating the above separation and purification process to ensure that all components are completely separated, purified and stored. When the additive is He, the first outlet of separator 2-3 is connected to He purification unit 2-10 via the fifth three-way reversing valve 2-9 for dedicated purification and storage of He. The second outlet is connected to CO2 purification unit 2-4 for CO2 purification and storage. The byproducts of CO2 purification unit 2-4 enter He purification unit 2-10 from its second outlet via the fourth three-way reversing valve 2-8 for further absorption of residual He. The residue remaining after processing by He purification unit 2-10 is returned to separator 2-3 for reprocessing via the second shut-off valve 2-13, achieving complete separation and purification of the working fluid. The module can flexibly adjust the opening and closing and flow direction of each reversing valve and shut-off valve according to the type of additive to achieve flow path switching. The purification flow paths of H2S and He additives are independent of each other, adapting to different mixed working fluid types, ensuring that the module maintains high efficiency and adaptability during separation, purification and recovery processes, and supporting rapid switching of working fluids in the system.

[0035] Preferably, the working fluid separation and purification module further includes a pressure reducing valve 2-1 and a second variable frequency working fluid pump 2-19, and the second cooler 2-18 is connected to the third inlet of the H2S absorption tower 2-14 via the second variable frequency working fluid pump 2-19; ​​the second outlet of the first three-way reversing valve 1-6 is connected to the inlet of the third three-way reversing valve 2-2 via the pressure reducing valve 2-1.

[0036] By introducing a pressure reducing valve 2-1 and a second variable frequency working fluid pump 2-19, the pressure regulation and fluid delivery capabilities of the working fluid separation and purification module are optimized, effectively improving separation efficiency and operational stability. Specifically, the working fluid separation and purification module also includes a pressure reducing valve 2-1, which is used to throttle and reduce the pressure of the working fluid from the first three-way reversing valve 1-6, facilitating efficient working fluid separation in the separator 2-3; and a second variable frequency working fluid pump 2-19, which is used to pressurize the H2S absorbent output from the cooler, ensuring that the fluid enters the third inlet of the H2S absorption tower 2-14 at sufficient pressure, realizing the recycling of the absorbent. At the same time, the variable frequency adjustment can dynamically match the flow rate and pressure required by the system, ensuring the continuous stability of the absorption process; the second outlet of the first three-way reversing valve 1-6 is connected to the inlet of the third three-way reversing valve 2-2 via the pressure reducing valve 2-1. The setting of the pressure reducing valve 2-1 precisely matches the operating conditions of the working fluid separation and purification module, avoiding pressure fluctuations from affecting the separation effect.

[0037] Preferably, the pure component storage tank group includes a first regulating valve 2-21, a second regulating valve 2-22, a third regulating valve 2-23, a fourth shut-off valve 2-5, a fifth shut-off valve 2-6, a sixth shut-off valve 2-11, a seventh shut-off valve 2-16, a CO2 storage tank 2-7, a He storage tank 2-12, and an H2S storage tank 2-17; wherein, the inlet of the CO2 storage tank 2-7 serves as the first inlet of the pure component storage tank group, and is sequentially connected to the outlet of the CO2 purification device 2-4 via the fifth shut-off valve 2-6 and the fourth shut-off valve 2-5; the inlet of the He storage tank 2-12 serves as the pure component... The second inlet of the storage tank group is connected to the outlet of the He purification unit 2-10 via the sixth shut-off valve 2-11; the inlet of the H2S storage tank 2-17 serves as the third inlet of the pure component storage tank group and is connected to the outlet of the H2S desorption tower 2-15 via the seventh shut-off valve 2-16; the outlet of the H2S storage tank 2-17 is connected to the inlet of the mixer 2-24 via the first regulating valve 2-21; the outlet of the He storage tank 2-12 is connected to the inlet of the mixer 2-24 via the second regulating valve 2-22; and the outlet of the CO2 storage tank 2-7 is connected to the inlet of the mixer 2-24 via the third regulating valve 2-23.

[0038] By introducing a combination of specific valves and storage tanks, effective isolation, precise storage, and on-demand proportioning control of the working fluid are achieved. Specifically, the inlet of CO2 storage tank 2-7 is connected to the outlet of CO2 purification unit 2-4 via the fifth shut-off valve 2-6 and the fourth shut-off valve 2-5. This dual shut-off valve design ensures safe isolation and prevents backflow of the working fluid when switching between the two branches of pure CO2 recovery and storage and CO2 recovery and storage purified from the mixed working fluid. The inlet of He storage tank 2-12 is connected to the outlet of He purification unit 2-10 via the sixth shut-off valve 2-11, similarly achieving independent storage and isolation of the He working fluid. The inlet of H2S storage tank 2-17 is connected to the outlet of H2S desorption tower 2-15 via the seventh shut-off valve 2-16, ensuring the purified storage of H2S working fluid and maintaining its chemical stability. At the outlet, the outlet of H2S storage tank 2-17 is connected to mixer 2-24 via the first regulating valve 2-21, the outlet of He storage tank 2-12 is connected to mixer 2-24 via the second regulating valve 2-22, and the outlet of CO2 storage tank 2-7 is connected to mixer 2-24 via the third regulating valve 2-23. These regulating valves precisely control the extraction flow rate of each working substance according to the target ratio, thereby achieving dynamic ratio adjustment during injection into the system and ensuring the accuracy and reliability of the working substance switching process.

[0039] Based on the same inventive concept, this invention also provides an adjustment method for a supercritical carbon dioxide cycle adaptive system. Using the supercritical carbon dioxide cycle adaptive system described above, the method determines the target working fluid type and target ratio based on the ambient temperature detected by an ambient temperature sensor. A controller then controls a switchable flow path control unit, a working fluid separation and purification module, a pure component storage tank group, and a working fluid preparation and injection unit to switch the current working fluid in the supercritical CO2 Brayton cycle subsystem to the target working fluid. Furthermore, based on the heat source temperature and flow rate detected by a heat source parameter sensor, the method adjusts the working fluid flow rate injected into the supercritical CO2 Brayton cycle subsystem by the working fluid preparation and injection unit. When the ambient temperature is below the first temperature threshold, a binary mixture of CO2 and He is selected as the target working medium type; when the ambient temperature is between the first and second temperature thresholds, pure CO2 is selected as the target working medium type; when the ambient temperature is above the second temperature threshold, a binary mixture of CO2 and H2S is selected as the target working medium type.

[0040] The adjustment method for a supercritical carbon dioxide cycle adaptive system provided by this invention solves the problem of reduced system efficiency during temperature fluctuations by selecting the appropriate working fluid type according to different ambient temperature ranges, ensuring that the inlet conditions of compressor 1-2 are always maintained in the near-critical region, thereby improving overall operating efficiency. Specifically, the supercritical carbon dioxide cycle adaptive system described above provides the hardware foundation for working fluid switching and adjustment, enabling the method to achieve dynamic adjustment. When the ambient temperature is below the first temperature threshold, a binary mixture of CO2 and He is selected as the working fluid. He is used to lower the critical temperature of the mixture, adapting to the low-temperature environment and preventing the inlet temperature of compressor 1-2 from deviating from the critical point. When the ambient temperature is between the first and second temperature thresholds, pure CO2 is selected as the working fluid, leveraging its inherent critical temperature characteristics to maintain efficient operation at moderate temperatures. When the ambient temperature is above the second temperature threshold, a binary mixture of CO2 and H2S is selected as the working fluid. H2S is used to raise the critical temperature of the mixture, coping with high-temperature conditions and ensuring stable operation of the system in the near-critical state. This segmented selection strategy based on ambient temperature achieves adaptive optimization of the working fluid type.

[0041] Preferably, when the target working fluid is a binary mixture of CO2 and He or a binary mixture of CO2 and H2S, the target critical temperature is calculated based on the ambient temperature and the preset heat exchange temperature difference, so that the target critical temperature is equal to the ambient temperature plus the preset heat exchange temperature difference, and the target ratio corresponding to the target critical temperature is determined by querying the pre-stored database of working fluid critical temperature and ratio relationship.

[0042] This method is limited to binary working fluid mixtures of CO2 and He or CO2 and H2S, ensuring that it only applies to operating conditions requiring ratio adjustments. It calculates the target critical temperature based on ambient temperature and a preset heat exchange temperature difference. Ambient temperature is a key parameter monitored in real time, and the preset heat exchange temperature difference serves as a fixed offset, both used to calculate the target critical temperature. This solves the problem of setting a reasonable target value, ensuring the target critical temperature is higher than the ambient temperature to maintain heat exchange efficiency. The target critical temperature is equal to the ambient temperature plus the preset heat exchange temperature difference, ensuring the working fluid remains in a near-critical state during operation and optimizing the power consumption of compressors 1-2. By querying a pre-stored database of working fluid critical temperatures and ratios, which stores critical temperature mappings for different ratios, the query operation achieves rapid matching, avoiding the complexity of real-time calculations. Finally, the target ratio corresponding to the target critical temperature is determined, and the ratio value is directly output, enabling the system to configure the working fluid to achieve the target critical temperature, thereby ensuring that the inlet parameters of compressors 1-2 remain stable near the critical point.

[0043] Preferably, the first temperature threshold is 288K and the second temperature threshold is 298K.

[0044] The first temperature threshold is 288K. When the ambient temperature is below this value, the system selects a binary mixture of CO2 and He as the working fluid, which helps to optimize the critical characteristics of the working fluid at lower temperatures and prevents the inlet conditions of compressor 1-2 from being far from the near-critical region. The second temperature threshold is 298K. When the ambient temperature is above this value, the system selects a binary mixture of CO2 and H2S as the working fluid, which helps to maintain operation near the critical point of the working fluid at higher temperatures and reduces the power consumption of compressor 1-2. The temperature threshold is set based on the ambient temperature range to ensure that the switching point is reasonable and to avoid efficiency loss and system instability caused by improper threshold settings.

[0045] In a specific embodiment of the present invention, a supercritical carbon dioxide cycle adaptive system includes a supercritical CO2 Brayton cycle system, a working fluid regulation and switching subsystem, and a monitoring and control subsystem. The supercritical CO2 Brayton cycle system may be, but is not limited to, a supercritical CO2 Brayton cycle system. Figure 1 The diagram shows a simple regenerative supercritical Brayton cycle, which is the most common supercritical Brayton cycle configuration used for waste heat recovery. This section uses this configuration as an example to illustrate the operation of a supercritical carbon dioxide cycle system where the type, ratio, and flow rate of the mixed working fluid need to be switched and adjusted according to operating conditions.

[0046] See Figure 1 The supercritical CO2 Brayton cycle system includes a first cooler 1-1, a compressor 1-2, a regenerator 1-3, a first heater 1-4, a turbine 1-5, a first three-way reversing valve 1-6, a first shut-off valve 1-7, and a second three-way reversing valve 1-8. The inlet flow of the first cooler 1-1 has two paths: one from the outlet of the first three-way reversing valve 1-6, and the other from the outlet of the first shut-off valve 1-7. The outlet of the first cooler 1-1 is connected to the inlet of the compressor 1-2. The outlet of the compressor 1-2 is connected to the heat absorption side inlet of the regenerator 1-3. The heat absorption side outlet of the regenerator 1-3 is connected to the heat absorption side inlet of the first heater 1-4. The heat absorption side outlet of the first heater 1-4 is connected to the inlet of the turbine 1-5. The outlet of the turbine 1-5 is connected to the heat release side inlet of the regenerator 1-3. The heat release side outlet of the regenerator 1-3 is connected to the inlet of the first three-way reversing valve 1-6. The first three-way reversing valve 1-6... The outlet is connected to the inlet of the first cooler 1-1, and the other outlet is connected to the inlet of the pressure reducing valve 2-1 of the working fluid regulation and switching subsystem. The inlet of the first shut-off valve 1-7 is connected to the heat absorption side outlet of the second heater 2-26 of the working fluid regulation and switching subsystem. The outlet of the first shut-off valve 1-7 is connected to the inlet of the first cooler 1-1. The heat release side inlet of the first heater 1-4 is connected to the heat source. The heat release side outlet of the first heater 1-4 is connected to the inlet of the second three-way reversing valve 1-8. The outlet of the second three-way reversing valve 1-8 has two paths: one is directly connected to the atmospheric environment, and the other is connected to the heat release side inlet of the second heater 2-26 of the working fluid regulation and switching subsystem.

[0047] The working fluid regulation and switching subsystem includes pressure reducing valve 2-1, third three-way reversing valve 2-2, separator 2-3, CO2 purification device 2-4, fourth shut-off valve 2-5, fifth shut-off valve 2-6, CO2 storage tank 2-7, fourth three-way reversing valve 2-8, fifth three-way reversing valve 2-9, He purification device 2-10, sixth shut-off valve 2-11, He storage tank 2-12, second shut-off valve 2-13, H2S absorption tower 2-14, H2S desorption tower 2-15, seventh shut-off valve 2-16, H2S storage tank 2-17, second cooler 2-18, second variable frequency working fluid pump 2-19, third shut-off valve 2-20, first regulating valve 2-21, second regulating valve 2-22, third regulating valve 2-23, mixer 2-24, first variable frequency working fluid pump 2-25, and second heater 2-26. Specifically, the outlet of pressure reducing valve 2-1 is connected to the inlet of the third three-way directional valve 2-2. The outlet of the third three-way directional valve 2-2 has two paths: one path connects to the inlet of CO2 storage tank 2-7 via the fifth shut-off valve 2-6, and the other path connects to the inlet of separator 2-3. The outlet of separator 2-3 has two paths: one path connects to the inlet of the fifth three-way directional valve 2-9, and the other path connects to CO2 purification device 2-4. The outlet of CO2 purification device 2-4 has two paths: one path connects to the inlet of the fourth three-way directional valve 2-8, and the other path connects to the inlet of the fourth shut-off valve 2-9. 5. The fifth shut-off valve 2-6 is connected to the inlet of CO2 storage tank 2-7. The outlet of CO2 storage tank 2-7 is connected to mixer 2-24 via the third regulating valve 2-23. The outlets of the fourth three-way reversing valve 2-8 and the fifth three-way reversing valve 2-9 are divided into two identical paths: one path is connected to the inlet of He purification unit 2-10, and the other path is connected to the inlet of H2S absorption tower 2-14. The outlet of He purification unit 2-10 has two paths: one path is connected to the inlet of separator 2-3 via the second shut-off valve 2-13, and the other path is connected to the inlet of separator 2-3 via the sixth shut-off valve 2-14. 11 is connected to the inlet of He storage tank 2-12. The outlet of He storage tank 2-12 is connected to mixer 2-24 via second regulating valve 2-22. The outlet of H2S absorption tower 2-14 has two paths: one is connected to the inlet of separator 2-3 via third shut-off valve 2-20, and the other is connected to the inlet of H2S desorption tower 2-15. The outlet of H2S desorption tower 2-15 has two paths: one is connected to the inlet of second cooler 2-18, and the other is connected to the inlet of H2S storage tank 2-17 via seventh shut-off valve 2-16. H2S storage... The outlet of tank 2-17 is connected to mixer 2-24 via first regulating valve 2-21. The outlet of second cooler 2-18 is connected to inlet of second variable frequency working fluid pump 2-19. The outlet of second variable frequency working fluid pump 2-19 is connected to inlet of H2S absorption tower 2-14. The outlet of mixer 2-24 is connected to inlet of first variable frequency working fluid pump 2-25. The outlet of first variable frequency working fluid pump 2-25 is connected to heat absorption side inlet of second heater 2-26. Heat absorption side outlet of second heater 2-26 is connected to supercritical CO2 Brayton cycle system.

[0048] In the working fluid conditioning and switching subsystem, switchable flow paths are formed between the cold-side outlet of the heater and the inlet of the cooler, and between the inlet of the cooler and the outlet of the working fluid conditioning and switching subsystem, respectively, through three-way reversing valves and shut-off valves. This allows the circulating working fluid to either directly enter the cooler for circulation or enter the working fluid conditioning and switching subsystem for working fluid switching, separation, and recovery. The system mainly includes three functional branches: a pure CO2 treatment branch, a CO2 / He treatment branch, and a CO2 / H2S treatment branch. The pure CO2 treatment branch is equipped with a pressure reducing valve, a shut-off valve, a CO2 purification device, and a CO2 storage tank. The CO2 / He treatment branch is equipped with a pressure reducing valve, a separator, a shut-off valve, a CO2 purification device, a CO2 storage tank, a three-way reversing valve, a He purification device (including but not limited to a membrane separation device), and a He storage tank, used for separating, purifying, and storing CO2 and He. The CO2 / H2S treatment branch is equipped with a pressure reducing valve, separator, shut-off valve, CO2 purification unit, CO2 storage tank, three-way directional valve, H2S absorption tower (including but not limited to MDEA chemical absorbent), H2S desorption tower, cooler, and H2S storage tank. It is used to separate CO2 and H2S, purify and store CO2, and absorb, desorb, purify, and store H2S. Pure CO2, He, and H2S can be injected into the mixer from their respective storage tanks via regulating valves as needed. The mixed working fluid is pressurized by a variable frequency pump, heated by a heater, and then injected into the power circulation via a shut-off valve. The pure CO2 treatment branch and the mixed working fluid treatment branch are switched via a three-way directional valve. The separator's top outlet is connected to the inlet of the He purification unit and the H2S absorption tower; the CO2 purification unit outlet is connected to the inlet of the He purification unit and the H2S absorption tower via three-way directional valves; the He purification unit outlet is connected to the separator inlet, and the H2S absorption tower outlet is connected to the separator inlet via two shut-off valves. The two three-way directional valves automatically switch paths according to the type of binary mixed working fluid additive, while the two shut-off valves automatically open and close according to the type of binary mixed working fluid additive. By controlling the two three-way directional valves and the two shut-off valves, the complete separation and purification process of the mixed working fluid is achieved.

[0049] The heat release side outlet of the supercritical CO2 Brayton cycle subsystem heater and the heat release side inlet of the working fluid regulation and switching subsystem heater are connected by a three-way reversing valve. When the system is used for waste heat recovery and utilization, the three-way reversing valve is adjusted to divert the flue gas at the heat release side outlet of the supercritical CO2 Brayton cycle subsystem heater, and part of the flue gas is diverted to the working fluid regulation and switching subsystem heater to heat the working fluid, thereby further improving the waste heat utilization rate.

[0050] The monitoring and control subsystem includes a sensor network deployed at key locations in the system, such as ambient temperature sensors, heat source temperature and flow sensors, and online component analyzers for the working fluid, as well as a central controller (including but not limited to PLCs and DCS). The controller receives real-time signals from all sensors and executes control measures: First, based on the threshold range of the ambient temperature (below 288 K, 288 K-298 K, above 298 K), it automatically decides whether to use pure CO2, CO2 / He, or CO2 / H2S as the working fluid. For binary mixed working fluids, it further calculates the target critical temperature based on the ambient temperature and a preset heat exchange temperature difference (e.g., 10 K), and uses this to retrieve the precise target ratio of the required additives from a database. Second, based on the temperature and flow parameters of the heat source, it calculates and adjusts the optimal flow rate of the working fluid required for the power cycle in real time. When a change in working fluid is required, the controller automatically operates the relevant valves according to a preset program, sequentially completing the separation and recovery of the old working fluid, the mixing and injection of the new working fluid, ultimately achieving seamless switching of the working fluid type.

[0051] As the ambient temperature changes, the system can automatically and quickly switch between and separate three different working fluids: pure CO2, CO2 / He, and CO2 / H2S. It also automatically adjusts the binary mixed working fluid ratio based on the ambient temperature and the set heat exchange temperature difference between the ambient temperature and the first cooler 1-1, ensuring that the working fluid parameters at the compressor 1-2 inlet are always maintained near the critical point of the working fluid. The monitoring and control subsystem includes an ambient temperature sensor, a heat source flow sensor, a heat source temperature sensor, a working fluid component analyzer, and a controller. The controller is connected to the sensors, the working fluid component analyzer, the second variable frequency working fluid pump 2-19, the first variable frequency working fluid pump 2-25, each three-way reversing valve, regulating valve, and shut-off valve, and is used to switch the working fluid type and flow rate according to the ambient temperature threshold, and to adjust the working fluid circulation flow rate according to the heat source flow rate and temperature. The He purification device 2-10 is implemented, but is not limited to, membrane separation. The membrane separation materials used include, but are not limited to, polyimide and polysulfone. The H2S separation and purification module uses chemical absorption, and the absorbent in the H2S absorption tower 2-14 includes, but is not limited to, an aqueous solution of methyldiethanolamine.

[0052] The system monitors ambient temperature and the temperature and flow rate of the heat source in real time. Based on the ambient temperature, it selects the working fluid type and calculates the target ratio. When the ambient temperature is below 288K, it selects a binary mixture of CO2 and He as the working fluid, calculating the target ratio of He to ensure the critical temperature of the mixture equals the ambient temperature plus a preset heat exchange temperature difference. When the ambient temperature is between 288K and 298K, it selects pure CO2 as the working fluid. When the ambient temperature is above 298K, it selects a binary mixture of CO2 and H2S as the working fluid, calculating the target ratio of H2S to ensure the critical temperature of the mixture equals the ambient temperature plus a preset heat exchange temperature difference. Based on the temperature and flow rate of the heat source, it calculates the required working fluid flow rate. If the current system working fluid is inconsistent with the target working fluid, it initiates a working fluid switching process, separating and storing the current working fluid, while simultaneously injecting a new working fluid into the system according to the target ratio. It continuously monitors the ambient temperature and heat source parameters, dynamically adjusting the working fluid ratio and flow rate.

[0053] This system monitors ambient temperature in real time and dynamically adjusts the type, ratio, and circulation flow of the mixed working fluid to ensure that the compressor inlet parameters are always maintained near the critical point of the working fluid. This significantly widens the temperature range for efficient system operation and improves thermal efficiency under all operating conditions. It can synchronously respond to changes in ambient temperature and fluctuations in heat source parameters, automatically adjusting the working fluid composition and flow rate, significantly improving the system's adaptability and stability under varying environmental and load conditions. It enables rapid switching, separation, and recovery of the mixed working fluid, allowing for the recycling of additives. This reduces working fluid replenishment costs while adapting to different climatic conditions and facilitates system maintenance and long-term reliable operation. Addressing the significant differences in heat source parameters in typical application scenarios such as solar energy, industrial waste heat, and geothermal energy, it achieves efficient recovery and conversion of heat sources of different grades through synchronous optimization of working fluid composition and flow rate, improving overall energy utilization efficiency.

[0054] See Figure 3 Three working fluid rapid switching and separation and recovery methods; Depending on the operating conditions, when the pure CO2 working medium needs to be switched, pure CO2 flows out from the supercritical CO2 Brayton cycle system through the first three-way reversing valve 1-6, flows through the pressure reducing valve 2-1 and the fifth shut-off valve 2-6 in sequence, and is stored in the CO2 storage tank 2-7, thus completing the separation, purification and storage of the working medium.

[0055] Similarly, when the CO2 / He working fluid needs to be switched, the CO2 / He working fluid flows into separator 2-3 via the first three-way reversing valve 1-6, pressure reducing valve 2-1, and third three-way reversing valve 2-2. A large amount of CO2 carrying a small amount of He enters CO2 purification unit 2-4 from the bottom of separator 2-3. The purified CO2 is stored in CO2 storage tank 2-7 from the bottom of CO2 purification unit 2-4 via the fourth shut-off valve 2-5 and fifth shut-off valve 2-6. The unpurified CO2 / He working fluid in CO2 purification unit 2-4... He enters the He purification unit 2-10 via the fourth three-way reversing valve 2-8. A large amount of He, carrying a small amount of CO2, enters the He purification unit 2-10 from the top of the separator 2-3 via the fifth three-way reversing valve 2-9. The purified He is stored in the He storage tank 2-12 from the bottom of the He purification unit 2-10 via the sixth shut-off valve 2-11. The unpurified CO2 / He flows out of the He purification unit 2-10 and returns to the separator 2-3 via the second shut-off valve 2-13 to continue the above process, completing the separation, purification and storage of the working fluid.

[0056] Similarly, when the CO2 / H2S working fluid needs to be switched, the CO2 / H2S working fluid flows into separator 2-3 through the first three-way reversing valve 1-6, pressure reducing valve 2-1, and the third three-way reversing valve 2-2. A large amount of CO2 carrying a small amount of H2S enters CO2 purification unit 2-4 from the bottom of separator 2-3. The purified CO2 is stored in CO2 storage tank 2-7 from the bottom of CO2 purification unit 2-4 through the fourth shut-off valve 2-5 and the fifth shut-off valve 2-6. The unpurified CO2 / H2S in CO2 purification unit 2-4 enters H2S absorption tower 2-14 through the fourth three-way reversing valve 2-8. A large amount of H2S carrying a small amount of CO2 enters H2S absorption tower 2-14 from the top of separator 2-3 through the fifth three-way reversing valve 2-9. After being absorbed by the absorbent, H2S enters H2S desorption tower 2-15 from the bottom of H2S absorption tower 2-14 to desorb the purified H2S. The absorbent is stored in H2S storage tank 2-17 from the top of H2S stripping tower 2-15 via the seventh shut-off valve 2-16. The absorbent is returned to H2S absorption tower 2-14 from the bottom of H2S stripping tower 2-15 via the second cooler 2-18 and the second variable frequency working fluid pump 2-19. The unpurified CO2 / H2S flows out from the top of H2S absorption tower 2-14 and returns to separator 2-3 via the third shut-off valve 2-20 to continue the above process, thus completing the separation, purification and storage of the working fluid.

[0057] While the above-mentioned working fluid is separated, purified and stored, the opening of the regulating valve above the storage tank of the required new working fluid is opened and controlled to adjust the ratio and flow rate. The new working fluid flows into the supercritical CO2 Brayton cycle system through the mixer 2-24, the first variable frequency working fluid pump 2-25, the second heater 2-26, and the first shut-off valve 1-7. When the new working fluid fills the entire supercritical CO2 Brayton cycle system, all shut-off valves and regulating valves are closed. The outlet of the first three-way reversing valve 1-6 is switched from being connected to the inlet of the pressure reducing valve 2-1 to being connected to the end of the first cooler 1-1, thus completing the working fluid switching.

[0058] By querying a pre-stored database of critical temperatures and ratios of working fluids, the target ratio of He or H2S is determined, enabling adaptive adjustment of the working fluid type, ratio, and flow rate.

[0059] In the supercritical CO2 binary working fluid, the molar ratio of additive He ranges from 0 to 0.14, and the molar ratio of additive H2S ranges from 0 to 0.5.

[0060] When the system is used for waste heat recovery and utilization, the method further includes: the controller monitors the temperature of the new working fluid at the outlet of the first variable frequency working fluid pump 2-25 through a temperature sensor, adjusts the three-way reversing valve to divert the flue gas at the outlet of the first heater 1-4 on the heat release side, and diverts part of the flue gas to the second heater 2-26 to heat the working fluid, thereby further improving the waste heat utilization rate.

[0061] See Figure 2 The relationship between the ratio of He or H2S and the critical temperature of the working medium is established by mapping the critical temperatures of the two working mediums to their ratios. The target ratio of He or H2S can be directly determined based on the critical temperature.

[0062] Assume this system is applied to a waste heat recovery scenario in a gas turbine power plant. Initially, the ambient temperature is 293 K (20 ℃), the system uses pure CO2 as the circulating working fluid, the ambient temperature sensor of the monitoring and control subsystem continuously monitors the data, and the heat source temperature and flow sensors monitor the flue gas parameters from the gas turbine.

[0063] Table 1. Examples of system efficiency calculations and efficiency improvements based on the present invention under different environmental conditions.

[0064] See Table 1: 1. Normal operation in pure CO2 mode: Table 1 Example 2: In this mode, the first three-way reversing valve 1-6 switches to a path that allows the working fluid at the outlet of the regenerator 1-3 to directly enter the first cooler 1-1, the first shut-off valve 1-7 closes, and the second three-way reversing valve 1-8 switches to an outlet connected to the environment. The working fluid flows in the power cycle: after being heated by the flue gas, it drives the turbine 1-5 to do work, then recovers waste heat through the regenerator 1-3, is cooled by the first cooler 1-1, compressed by the compressor 1-2, and then re-enters the regenerator 1-3 to absorb heat, completing the cycle.

[0065] 2. A decrease in ambient temperature triggers the switching of the working fluid to CO2 / He mode: Table 1 Example 1-1: When the ambient temperature sensor detects that the temperature drops to 10 ℃ (283K), which is lower than the first threshold of 288K, the controller determines that it needs to switch to the CO2 / He mixed working fluid mode to reduce the critical temperature of the mixed working fluid and bring it closer to the new ambient temperature.

[0066] First, the pure CO2 recovery process is initiated: the controller switches the first three-way reversing valve 1-6 to the path connecting to the working fluid regulation and switching subsystem, and opens the fifth shut-off valve 2-6. The circulating pure CO2 working fluid, after being depressurized by the pressure reducing valve 2-1, is directly stored in the CO2 storage tank 2-7 through the third three-way reversing valve 2-2 and the fifth shut-off valve 2-6. Simultaneously, based on the current ambient temperature (e.g., 273 K) and the preset heat exchange temperature difference (e.g., 10 K), the controller calculates the target mixed working fluid critical temperature to be 283 K, and determines the required target molar ratio of He to be 7% by querying the pre-stored CO2 / He mixed working fluid phase database.

[0067] Next, the new working fluid CO2 / He preparation and injection process is executed: the controller adjusts the opening of regulating valves 2-23 and 2-22 according to the target flow rate and ratio, so that pure CO2 in CO2 storage tank 2-7 and pure He in He storage tank 2-12 flow into mixer 2-24 for mixing. The mixed working fluid is pressurized to above supercritical pressure by the first variable frequency working fluid pump 2-25, and then flows through the second heater 2-26. At this time, the controller adjusts the second three-way reversing valve 1-8 to guide a portion of the waste heat flue gas from the first heater 1-4 to the second heater 2-26, heating the new working fluid to a supercritical state. Finally, the first shut-off valve 1-7 is opened to inject the prepared supercritical CO2 / He mixed working fluid into the inlet of the cooler of the power cycle.

[0068] When the online component analyzer confirms that the new working fluid has filled the entire cycle and the ratio has reached the target value, that is, when the working fluid at the outlet of the exothermic side of the regenerator 1-3 is consistent with the target working fluid, the controller will switch the first three-way reversing valve 1-6 back to the direct cooling path and close the relevant inlet and outlet valves of the working fluid regulation subsystem, thus completing the switch from pure CO2 to CO2 / He mixed working fluid.

[0069] 3. A rapid increase in ambient temperature within a short period triggers the switching of the working fluid to CO2 / H2S mode: Table 1 Example 3-2: Similarly, when the ambient temperature rises to 308 K (35 ℃), which is higher than the second threshold of 298 K, the controller determines that it needs to switch to the CO2 / H2S mixed working fluid mode to increase the critical temperature.

[0070] Used working fluid recovery process: If the current working fluid is CO2 / He, recovery is initiated. The controller operates the valves to allow the working fluid to enter separator 2-3. Most of the CO2 and a small amount of He enter the CO2 purification unit 2-4 from the bottom. The purified CO2 is stored in CO2 storage tank 2-7 via the fourth shut-off valve 2-5 and the fifth shut-off valve 2-6. The He-rich stream enters the He purification unit 2-10 (e.g., polyimide membrane separation) from the top via the fifth three-way reversing valve 2-9 and the unpurified stream from CO2 purification unit 2-4. The purified He is stored in He storage tank 2-12 via the sixth shut-off valve 2-11. The unpurified stream returns to the separator via the second shut-off valve 2-13. This process continues until the working fluid is basically separated.

[0071] New working fluid preparation and injection process: Based on the current ambient temperature (e.g., 308K) and the preset heat exchange temperature difference (e.g., 10K), the controller calculates the critical temperature of the target mixed working fluid to be 318K, and determines the target molar ratio of H2S to be 35%. Then, the working fluid is extracted from CO2 storage tank 2-7 and H2S storage tank 2-17 according to the flow rate and ratio, mixed in mixer 2-24, and after pumping and heating, injected into the power cycle through the first shut-off valve 1-7 to complete the switching to CO2 / H2S working fluid.

[0072] Similarly, when the online component analyzer confirms that the new working fluid has filled the entire cycle and the ratio has reached the target value, the controller will switch the first three-way reversing valve 1-6 back to the direct cooling path and close the relevant inlet and outlet valves of the working fluid conditioning subsystem to complete the switching of the working fluid.

[0073] 4. A decrease in ambient temperature triggers the switching of the working fluid to pure CO2 mode: When the ambient temperature drops to 295 K, the controller determines that it needs to switch to pure CO2 working fluid operation.

[0074] Used working fluid recovery process: If the current working fluid is CO2 / H2S, recovery is initiated. The controller operates the valves to allow the working fluid to enter separator 2-3. Most of the CO2 and a small amount of H2S enter the CO2 purification unit 2-4 from the bottom. The purified CO2 is stored in CO2 storage tank 2-7 via the fourth shut-off valve 2-5 and the fifth shut-off valve 2-6. The unpurified CO2 / H2S in CO2 purification unit 2-4 enters the H2S absorption tower 2-14 via the fourth three-way reversing valve 2-8 and the H2S-rich stream from the top outlet of separator 2-3 via the fifth three-way reversing valve 2-9. The absorbent is MDEA solution. After the H2S is absorbed by the absorbent, it enters the H2S desorption tower 2-15 from the bottom of the H2S absorption tower 2-14 to desorb and purify the H2S. The absorbent is stored in H2S storage tank 2-17 from the top of H2S stripping tower 2-15 via the seventh shut-off valve 2-16. The absorbent is returned to H2S absorption tower 2-14 from the bottom of H2S stripping tower 2-15 via the second cooler 2-18 and the second variable frequency working fluid pump 2-19. The unpurified CO2 / H2S flows out from the top of H2S absorption tower 2-14 and returns to separator 2-3 via the third shut-off valve 2-20 to continue the above process, thus completing the separation, purification and storage of the working fluid.

[0075] New working fluid preparation and injection process: The controller calculates the target flow rate of CO2. Then, the working fluid is extracted from CO2 storage tank 2-7 according to the flow rate and proportion, mixed in mixer 2-24, pumped and heated, and then injected into the power cycle through the first shut-off valve 1-7 to complete the switching of pure CO2 working fluid.

[0076] Similarly, when the online component analyzer confirms that the new working fluid has filled the entire cycle and the ratio has reached the target value, the controller will switch the first three-way reversing valve 1-6 back to the direct cooling path and close the relevant inlet and outlet valves of the working fluid conditioning subsystem to complete the switching of the working fluid.

[0077] 4. Flow rate regulation during heat source fluctuations: 1. Pure CO2 mode: Based on real-time flue gas flow and temperature, when the flue gas flow or temperature changes and the working fluid flow needs to be changed, if the current working fluid is CO2, the first three-way reversing valve 1-6 switches to the inlet of the pressure reducing valve 2-1, and the working fluid directly enters the working fluid regulation and switching subsystem. The third three-way reversing valve 2-2 switches to connect with the inlet of the CO2 storage tank 2-7 via the fifth shut-off valve 2-6, and the fifth shut-off valve 2-6 opens, completing the old working fluid storage process. At the same time, the controller controls the first shut-off valve 1-7 and the third regulating valve 2-23 to open, and regulates the three-way reversing valve to divert the flue gas from the heat release side outlet of the first heater 1-4, diverting part of the flue gas to the second heater 2-26 to heat the working fluid. The new working fluid enters the mixer 2-24 from the outlet of the CO2 storage tank 2-7 through the third regulating valve 2-23, and flows sequentially through the first variable frequency working fluid pump 2-25, the second heater 2-26, and the first shut-off valve 1-7 into the supercritical CO2 Brayton cycle system, starting the circulation process from the first cooler 1-1. When the working fluid flow rate at the outlet of the heat release side of the regenerator 1-3 is detected to be consistent with the target flow rate, the system closes all shut-off valves. The first three-way reversing valve 1-6 switches to the path that allows the working fluid at the outlet of the heat release side of the regenerator 1-3 to directly enter the first cooler 1-1, and the second three-way reversing valve 1-8 switches to the outlet connected to the environment.

[0078] 2CO2 / H2S mode Based on real-time flue gas flow and temperature, when changes in flue gas flow or temperature necessitate altering the working fluid flow, the controller switches the first three-way directional valve 1-6 to the inlet of the pressure reducing valve 2-1, allowing the working fluid to directly enter the working fluid regulation and switching subsystem. Used working fluid recovery process: If the current working fluid is CO2 / H2S, recovery is initiated. The controller operates the valves to allow the working fluid to enter separator 2-3. Most of the CO2 and a small amount of H2S enter the CO2 purification unit 2-4 from the bottom. The purified CO2 is stored in CO2 storage tank 2-7 via the fourth shut-off valve 2-5 and the fifth shut-off valve 2-6. The unpurified CO2 / H2S in CO2 purification unit 2-4 enters the H2S absorption tower 2-14 via the fourth three-way reversing valve 2-8 and the H2S-rich stream from the top outlet of separator 2-3 via the fifth three-way reversing valve 2-9. After being absorbed by the absorbent, the H2S enters the H2S desorption tower 2-15 from the bottom of the H2S absorption tower 2-14 to desorb and purify the H2S. The absorbent is stored in H2S storage tank 2-17 from the top of H2S stripping tower 2-15 via the seventh shut-off valve 2-16. The absorbent is returned to H2S absorption tower 2-14 from the bottom of H2S stripping tower 2-15 via the second cooler 2-18 and the second variable frequency working fluid pump 2-19. The unpurified CO2 / H2S flows out from the top of H2S absorption tower 2-14 and returns to separator 2-3 via the third shut-off valve 2-20 to continue the above process, thus completing the separation, purification and storage of the working fluid.

[0079] New working fluid preparation and injection process: The controller calculates the target flow rate and ratio of H2S. Then, the working fluid is extracted from CO2 storage tank 2-7 and H2S storage tank 2-17 according to the flow rate and ratio, mixed in mixer 2-24, pumped and heated, and then injected into the power cycle through the first shut-off valve 1-7 to complete the switch to CO2 / H2S working fluid.

[0080] Similarly, when the online component analyzer confirms that the new working fluid has filled the entire cycle and the ratio has reached the target value, the controller will switch the first three-way reversing valve 1-6 back to the direct cooling path and close the relevant inlet and outlet valves of the working fluid conditioning subsystem to complete the switching of the working fluid.

[0081] As can be seen from the above embodiments and the efficiency results in Table 1, this system achieves dual self-adaptation to ambient temperature and heat source parameters, can quickly and automatically switch between three working fluids, and optimize operating parameters in real time, thereby significantly expanding the efficient operating range of the supercritical CO2 cycle system and improving its economy and reliability in various industrial applications.

[0082] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A supercritical carbon dioxide cycle adaptive system, characterized in that, It includes a supercritical CO2 Brayton cycle subsystem, a working fluid regulation and switching subsystem, and a monitoring and control subsystem. The working fluid regulation and switching subsystem is selectively connected to the supercritical CO2 Brayton cycle subsystem through a switchable flow path control unit. The working fluid regulation and switching subsystem includes: a working fluid separation and purification module, used to separate and purify the mixed working fluid from the supercritical CO2 Brayton cycle subsystem into single-component working fluids; a pure component storage tank group, connected to the working fluid separation and purification module, used to store each purified single-component working fluid separately; and a working fluid preparation and injection unit, connected to the pure component storage tank group, used to extract single-component working fluids from the pure component storage tank group according to the target ratio and inject them into the supercritical CO2 Brayton cycle subsystem. The monitoring and control subsystem includes an ambient temperature sensor, a heat source parameter sensor, and a controller. The controller is connected to the ambient temperature sensor, the heat source parameter sensor, a switchable flow path control unit, a working fluid separation and purification module, a pure component storage tank group, and a working fluid preparation and injection unit.

2. The supercritical carbon dioxide cycle adaptive system according to claim 1, characterized in that, The supercritical CO2 Brayton cycle subsystem includes a first cooler (1-1), a compressor (1-2), a regenerator (1-3), a first heater (1-4), and a turbine (1-5); the switchable flow path control unit includes a first three-way reversing valve (1-6) and a first shut-off valve (1-7). The outlet of the first cooler (1-1) is connected to the inlet of the first three-way reversing valve (1-6) in sequence via the compressor (1-2), the heat absorption side of the regenerator (1-3), the heat absorption side of the first heater (1-4), the turbine (1-5), and the heat release side of the regenerator (1-3). The first outlet of the first three-way reversing valve (1-6) is connected to the inlet of the first cooler (1-1), and the second outlet of the first three-way reversing valve (1-6) is connected to the inlet of the working fluid regulation and switching subsystem. The outlet of the working fluid regulation and switching subsystem is connected to the inlet of the first cooler (1-1) via the first shut-off valve (1-7).

3. The supercritical carbon dioxide cycle adaptive system according to claim 2, characterized in that, The working fluid preparation and injection unit includes a mixer (2-24), a first variable frequency working fluid pump (2-25), and a second heater (2-26). The outlet of the mixer (2-24) is connected to the heat absorption side inlet of the second heater (2-26) via the first variable frequency working fluid pump (2-25) to pressurize the mixed target working fluid to supercritical pressure. The heat absorption side outlet of the second heater (2-26) is connected to the first shut-off valve (1-7) as the outlet of the working fluid regulation and switching subsystem. The heat release side inlet of the second heater (2-26) is connected to the heat release side outlet of the first heater (1-4). A heat source is introduced into the heat release side inlet of the first heater (1-4), and the heat release side outlet of the second heater (2-26) is used to output flue gas. The inlet of the mixer (2-24) is connected to the outlet of the pure component storage tank group.

4. The supercritical carbon dioxide cycle adaptive system according to claim 3, characterized in that, The flow path control unit that can be switched also includes a second three-way reversing valve (1-8). The heat release side outlet of the first heater (1-4) is connected to the inlet of the second three-way reversing valve (1-8). The first outlet of the second three-way reversing valve (1-8) is connected to the heat release side inlet of the second heater (2-26). The second outlet of the second three-way reversing valve (1-8) is used to output flue gas.

5. The supercritical carbon dioxide cycle adaptive system according to claim 3, characterized in that, The working fluid separation and purification module includes a third three-way reversing valve (2-2), a separator (2-3), a CO2 purification device (2-4), a fourth three-way reversing valve (2-8), a fifth three-way reversing valve (2-9), a He purification device (2-10), a second shut-off valve (2-13), an H2S absorption tower (2-14), an H2S desorption tower (2-15), a second cooler (2-18), and a third shut-off valve (2-20). Among them, the inlet of the third three-way reversing valve (2-2) serves as the inlet of the working fluid regulation and switching subsystem and is connected to the second outlet of the first three-way reversing valve (1-6). The first outlet of the third three-way reversing valve (2-2) is connected to the inlet of the separator (2-3). The first outlet of the separator (2-3) is connected to the inlet of the fifth three-way reversing valve (2-9). The first outlet of the fifth three-way reversing valve (2-9) is connected to the first inlet of the H2S absorption tower (2-14). The first outlet of the absorption tower (2-14) is connected to the inlet of the separator (2-3) via the third shut-off valve (2-20). The second outlet of the separator (2-3) is connected to the inlet of the CO2 purification unit (2-4). The first outlet of the CO2 purification unit (2-4) is connected to the first inlet of the pure component storage tank group. The second outlet of the CO2 purification unit (2-4) is connected to the inlet of the fourth three-way reversing valve (2-8). The first outlet of the three-way reversing valve (2-8) is connected to the second inlet of the H2S absorption tower (2-14). The second outlet of the fourth three-way reversing valve (2-8) is connected to the inlet of the He purification unit (2-10). The first outlet of the He purification unit (2-10) is connected to the second inlet of the pure component storage tank group. The second outlet of the He purification unit (2-10) is connected to the inlet of the separator (2-3) via the second shut-off valve (2-13). The second outlet of the fifth three-way reversing valve (2-9) is connected to the inlet of the He purification unit (2-10). The second outlet of the absorption tower (2-14) is connected to the inlet of the H2S desorption tower (2-15). The first outlet of the H2S desorption tower (2-15) is connected to the third inlet of the pure component storage tank group. The second outlet of the H2S desorption tower (2-15) is connected to the third inlet of the H2S absorption tower (2-14) via the second cooler (2-18).

6. The supercritical carbon dioxide cycle adaptive system according to claim 5, characterized in that, The working fluid separation and purification module also includes a pressure reducing valve (2-1) and a second variable frequency working fluid pump (2-19). The second cooler (2-18) is connected to the third inlet of the H2S absorption tower (2-14) via the second variable frequency working fluid pump (2-19). The second outlet of the first three-way reversing valve (1-6) is connected to the inlet of the third three-way reversing valve (2-2) via the pressure reducing valve (2-1).

7. The supercritical carbon dioxide cycle adaptive system according to claim 6, characterized in that, The pure component storage tank group includes a first regulating valve (2-21), a second regulating valve (2-22), a third regulating valve (2-23), a fourth shut-off valve (2-5), a fifth shut-off valve (2-6), a sixth shut-off valve (2-11), a seventh shut-off valve (2-16), a CO2 storage tank (2-7), a He storage tank (2-12), and an H2S storage tank (2-17). The inlet of the CO2 storage tank (2-7) serves as the first inlet of the pure component storage tank group and is connected to the outlet of the CO2 purification unit (2-4) via the fifth shut-off valve (2-6) and the fourth shut-off valve (2-5); the inlet of the He storage tank (2-12) serves as the second inlet of the pure component storage tank group and is connected to the outlet of the He purification unit (2-10) via the sixth shut-off valve (2-11); the inlet of the H2S storage tank (2-17) serves as the third inlet of the pure component storage tank group and is connected to the outlet of the H2S desorption tower (2-15) via the seventh shut-off valve (2-16). The outlet of the H2S storage tank (2-17) is connected to the inlet of the mixer (2-24) via the first regulating valve (2-21); the outlet of the He storage tank (2-12) is connected to the inlet of the mixer (2-24) via the second regulating valve (2-22); and the outlet of the CO2 storage tank (2-7) is connected to the inlet of the mixer (2-24) via the third regulating valve (2-23).

8. A method for regulating a supercritical carbon dioxide cycle adaptive system, characterized in that, The supercritical carbon dioxide cycle adaptive system as described in any one of claims 1 to 7 determines the target working fluid type and target ratio based on the ambient temperature detected by the ambient temperature sensor, and controls the switchable flow path control unit, working fluid separation and purification module, pure component storage tank group and working fluid preparation and injection unit through the controller to switch the current working fluid in the supercritical CO2 Brayton cycle subsystem to the target working fluid; and adjusts the working fluid flow rate injected into the supercritical CO2 Brayton cycle subsystem by the working fluid preparation and injection unit based on the heat source temperature and flow rate detected by the heat source parameter sensor. When the ambient temperature is below the first temperature threshold, a binary mixture of CO2 and He is selected as the target working fluid type. When the ambient temperature is between the first temperature threshold and the second temperature threshold, pure CO2 is selected as the target working fluid type. When the ambient temperature is higher than the second temperature threshold, a binary mixture of CO2 and H2S is selected as the target working fluid type.

9. The adjustment method for a supercritical carbon dioxide cycle adaptive system according to claim 8, characterized in that, When the target working fluid is a binary mixture of CO2 and He or a binary mixture of CO2 and H2S, the target critical temperature is calculated based on the ambient temperature and the preset heat exchange temperature difference, so that the target critical temperature is equal to the ambient temperature plus the preset heat exchange temperature difference. The target ratio corresponding to the target critical temperature is determined by querying the pre-stored database of working fluid critical temperature and ratio relationship.

10. The adjustment method for a supercritical carbon dioxide cycle adaptive system according to claim 8, characterized in that, The first temperature threshold is 288K, and the second temperature threshold is 298K.

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