A supercritical carbon dioxide power generation system and its power regulation method

Abstract

The present application provides a supercritical carbon dioxide cycle power generation system and its power regulation method. The cycle power generation system includes a circulation pipeline and a drive unit, a power generation unit, a regenerator assembly, a main heater, a shunt, a pre-cooler and a reheater disposed in the circulation pipeline. The drive unit and the power generation unit of the present power generation system form a split-shaft layout, decoupling the complex supercritical carbon dioxide system mechanically, increasing the adjustable parameters and making the off-design conditions more flexible. When operating under off-design conditions, instead of discharging the supercritical carbon dioxide working fluid in the system, the output power of the driving turbine and the power generation turbine is changed by adjusting the opening degrees of the first, second and third regulating valves. The rotational speed of the power generation unit is generally a constant rotational speed, and the rotational speed of the drive unit is adjustable. The increased or decreased generated power is flexibly taken over and adjusted by the drive unit to meet and cooperate with the demand for variable power without discharging or increasing the supercritical carbon dioxide working fluid in the system, still ensuring the stability and high efficiency of the system.

Description

Technical Field

[0001] The present application relates to the technical field of supercritical carbon dioxide cycle power generation, and more particularly, to a supercritical carbon dioxide cycle power generation system and a power regulation method thereof. Background Art

[0002] The supercritical carbon dioxide cycle power generation system benefits from the good thermal properties of the carbon dioxide critical point: the critical conditions are easily achieved (30.978 °C, 7.377 MPa), the density in the supercritical state is similar to that of a liquid, the compression factor is between 0.2 - 0.5, the surface tension is small, the thermal conductivity is larger than that of the atmospheric gas, the viscosity is low, etc., and it has the characteristics of high efficiency, compactness, etc., and has high economy.

[0003] The volumetric method for power regulation is one of the commonly used methods for closed-cycle power generation systems, and it has the advantages of convenient regulation and high off-design efficiency. It is very effective in a closed cycle with an ideal gas (such as helium) as the working fluid. Because the pressure of an ideal gas changes proportionally with the density, when the mass flow rate of the system is reduced, the pressure and density of the working fluid will decrease, but the inlet volume flow rate of the turbine equipment remains unchanged. The compressor and the turbine operate at similar design points, and the cycle can maintain high efficiency within a large power range.

[0004] However, the physical properties of carbon dioxide change non-linearly and even undergo mutations near the critical point. During the volumetric regulation process, it is inevitable that the inlet pressure of the main compressor will decrease due to the reduction of the working fluid in the system and reach near the critical point. Therefore, it may bring unpredictable system stability problems, making it difficult for the system to maintain its original stability and high efficiency.

[0005] In addition, for existing supercritical carbon dioxide cycle power generation systems, their power generation is generally constant. When facing off-design conditions, they cannot flexibly adjust the power generation, and cannot cope with variable power generation and power consumption conditions. Summary of the Invention

[0006] The purpose of the present application is to provide a supercritical carbon dioxide cycle power generation system and a power regulation method thereof. By setting a split-shaft layout structure for the drive unit and the generator unit, the number of adjustable parameters is increased, and the system power generation can be flexibly adjusted without discharging or adding system working fluid, while maintaining the stability and high efficiency of the system to meet the off-design power generation requirements.

[0007] The present application provides a supercritical carbon dioxide circulation power generation system, including a circulation pipeline and a driving unit, a generator unit, a regenerator assembly, a main heater, a diverter, a precooler and a reheater arranged in the circulation pipeline. The regenerator assembly includes a high-temperature regenerator, a low-temperature regenerator and a mixer. The driving unit includes a starter and a driving turbine and a main compressor driven by the starter. The generator unit includes an initiator and a power generation turbine and a recompressor connected to the initiator.

[0008] The two outlets of the splitter are connected to the main compressor inlet and the recompressor inlet respectively. A precooler is arranged between the splitter and the main compressor, and a first regulating valve is arranged between the splitter and the recompressor. The main compressor outlet is connected to the cold source side inlet of the low-temperature regenerator, and the cold source side outlet of the low-temperature regenerator and the recompressor outlet are connected to the two inlets of the mixer respectively; the outlet of the mixer is connected to the cold source side inlet of the high-temperature regenerator, and the cold source side outlet of the high-temperature regenerator is connected to the main heater inlet, and the main heater outlet is connected to the driving turbine inlet. The driving turbine outlet is divided into a first branch and a second branch. The first branch is connected to the power generation turbine inlet, and the second branch is connected to the heat source side inlet of the high-temperature regenerator. The second regulating valve and the reheater are arranged in sequence on the first branch, and the third regulating valve is arranged on the second branch. The power generation turbine outlet is connected to the heat source side inlet of the high-temperature regenerator, and the heat source side outlet of the high-temperature regenerator is connected to the heat source side inlet of the low-temperature regenerator, and the heat source side outlet of the low-temperature regenerator is connected to the splitter inlet. When working, supercritical carbon dioxide working fluid is filled into various places of the circulation pipeline.

[0009] In an practicable solution, the supercritical carbon dioxide cycle power generation system includes a storage tank storing carbon dioxide working fluid, and the storage tank is connected to a circulation pipeline from a low-temperature regenerator to an inlet of a diverter.

[0010] In an implementable solution, the inlet of the storage tank is connected to the circulation pipeline through an inlet valve, and the outlet of the storage tank is connected to the circulation pipeline through an outlet valve.

[0011] In an implementable solution, a pressure boosting device is provided in the storage tank, and the pressure boosting device is used to increase the pressure of the carbon dioxide working fluid at the outlet valve.

[0012] In an implementable solution, the first regulating valve, the second regulating valve and the third regulating valve are electric regulating valves. The supercritical carbon dioxide cycle power generation system includes a main control device, which is at least connected to the first regulating valve, the second regulating valve and the third regulating valve for adjusting the valve opening.

[0013] In an implementable solution, the main control device is connected to the main heater and the reheater in communication to control the heating power of the main heater and the reheater.

[0014] In an implementable solution, a pressure detection sensor is provided at the outlet of the driving turbine. The pressure detection sensor is communicatively connected to the main control device, and the main control device adjusts the heating power of the main heater according to the pressure information of the pressure detection sensor.

[0015] In a second aspect, the present application provides a power regulation method for a supercritical carbon dioxide cycle power generation system as described above, including:

[0016] S1. Determine the real-time power generation power W before power regulation m ;

[0017] S2. Determine the target power generation power W after regulation t ;

[0018] S3. Based on the magnitude difference between the target power generation power W t and the real-time power generation power W before regulation m , adjust the opening degrees of the first regulating valve, the second regulating valve, and the third regulating valve.

[0019] In an implementable solution, in step S3, based on the magnitude difference between the target power generation power W t and the real-time power generation power W before regulation m , the step of adjusting the opening degrees of the first regulating valve, the second regulating valve, and the third regulating valve includes:

[0020] S31. Determine the power difference ΔW between the target power generation power W t and the real-time power generation power W before regulation m ; t-m ;

[0021] S32. Judge whether the absolute value of the power difference ΔW t-m is less than or equal to a first preset difference; if so, go to step S33; if not, go to step S34;

[0022] S33. Keep the current opening degrees of the first regulating valve, the second regulating valve, and the third regulating valve unchanged;

[0023] S34. Judge whether the target power generation power W t is less than the real-time power generation power W before regulation m ; if W t is less than W m , go to step S35; if W t is greater than W m , go to step S36;

[0024] S35. Adjust the opening degree of the second regulating valve downwards, the opening degree of the third regulating valve upwards, and the opening degree of the first regulating valve upwards according to a preset unit opening measure;

[0025] S36. Increase the opening degree of the second regulating valve, decrease the opening degree of the third regulating valve, and decrease the opening degree of the first regulating valve according to a preset unit.

[0026] S37. Determine the adjusted real-time power generation W a , and determine whether the absolute value of the difference between the adjusted real-time power generation W a and the target power generation W t is less than or equal to a second preset difference; if so, complete the adjustment of the opening degrees of the first regulating valve, the second regulating valve, and the third regulating valve; if not, repeat steps S35 and S37, or repeat steps S36 and S37.

[0027] In an implementable solution, before step S3, it further includes: S03. Obtain the outlet pressure P0 of the driving turbine before the regulating valve is adjusted;

[0028] After step S3, it further includes:

[0029] S4. Obtain the outlet pressure P of the driving turbine after the regulating valve is adjusted t ;

[0030] S5. Determine whether the absolute value of the difference between the outlet pressure P t and the outlet pressure P0 is less than or equal to a preset pressure difference; if so, keep the current heating power of the main heater unchanged; if not, adjust the heating power of the main heater, and repeat steps S4 to S5 until the difference between the outlet pressure P t and the outlet pressure P0 is controlled within a predetermined difference range.

[0031] Compared with the prior art, the beneficial effects of the present application at least include the following.

[0032] The supercritical carbon dioxide cycle power generation system of the present application includes a driving unit and a power generation unit, forming a split-shaft layout, decoupling the complex supercritical two-system mechanically, so that the adjustable parameters increase and the off-design conditions are more flexible.

[0033] The supercritical carbon dioxide cycle power generation system of the present application, when operating under off-design conditions (changing the power generation), does not need to discharge the supercritical two working medium in the system (that is, does not need to adopt the variable volume method), but relies on adjusting the opening degrees of the first, second, and third regulating valves to realize the change of the output power of the driving turbine and the power generation turbine, rather than simply reducing or increasing the system pressure. The rotational speed of the power generation unit is generally a constant rotational speed, and the rotational speed of the driving unit is adjustable. The increased or decreased power generation is flexibly taken over and adjusted by the driving unit to adapt to and cooperate with the demand for variable power. It can ensure the operation stability and high efficiency of the system without discharging or increasing the supercritical two working medium in the system during the power adjustment process.

[0034] For example, when operating at reduced power, there is no need to discharge the supercritical working fluid within the system (i.e., there is no need to adopt the variable volume method). Instead, by adjusting the opening degrees of the first, second, and third regulating valves, the output powers of the driving turbine and the power generation turbine are changed, rather than simply reducing the system pressure. Therefore, the inlet conditions of the main compressor will not enter the critical point but only remain relatively close to the critical point. As a result, the power regulation of this system can bypass the influence of the critical point of supercritical carbon dioxide, enabling the system to maintain operational stability and high efficiency during the power regulation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] To more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present application and should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings.

[0036] Figure 1 FIG. is a schematic diagram showing the composition of a supercritical carbon dioxide cycle power generation system according to an embodiment of the present application.

[0037] Figure 2 FIG. is a schematic diagram showing the composition of another supercritical carbon dioxide cycle power generation system according to an embodiment of the present application.

[0038] Figure 3 FIG. is a flowchart of a power regulation method for a supercritical carbon dioxide cycle power generation system according to an embodiment of the present application.

[0039] In the figure: 1, driving unit; 11, starting machine; 12, driving turbine; 13, main compressor; 2, generating unit; 21, starting and generating integrated machine; 22, power generation turbine; 23, recompressor; 3, recuperator assembly; 31, high-temperature recuperator; 32, low-temperature recuperator; 33, mixer; 4, main heater; 5, diverter; 6, precooler; 7, reheater; 8, storage tank; 81, inlet valve; 82, outlet valve; 101, first regulating valve; 102, second regulating valve; 103, third regulating valve; 100, circulation pipeline; 200, main control device; 300, pressure detection sensor. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Usually, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0042] like Figure 1 As shown, the embodiment of the present application first provides a supercritical carbon dioxide circulation power generation system, including a circulation pipeline 100 and a driving unit 1, a generator set 2, a regenerator assembly 3, a main heater 4, a diverter 5, a precooler 6 and a reheater 7 arranged in the circulation pipeline 100. The regenerator assembly 3 includes a high-temperature regenerator 31, a low-temperature regenerator 32 and a mixer 33. The driving unit 1 includes a starter 11 and a driving turbine 12 and a main compressor 13 driven by the starter 11. The generator set 2 includes an initiator 21 and a power generation turbine 22 and a recompressor 23 connected to the initiator 21.

[0043] Among them, the two outlets of the splitter 5 are respectively connected to the inlet of the main compressor 13 and the inlet of the recompressor 23, a precooler 6 is arranged between the splitter 5 and the main compressor 13, and a first regulating valve 101 is arranged between the splitter 5 and the recompressor 23. The outlet of the main compressor 13 is connected to the cold source side inlet of the low-temperature regenerator 32, and the cold source side outlet of the low-temperature regenerator 32 and the outlet of the recompressor 23 are respectively connected to the two inlets of the mixer 33. The outlet of the mixer 33 is connected to the cold source side inlet of the high-temperature regenerator 31, and the cold source side outlet of the high-temperature regenerator 31 is connected to the inlet of the main heater 4, and the outlet of the main heater 4 is connected to the inlet of the driving turbine 12.

[0044] The outlet of the driving turbine 12 is divided into a first branch and a second branch, the first branch is connected to the inlet of the power generation turbine 22, and the second branch is connected to the heat source side inlet of the high temperature regenerator 31. The first branch is provided with a second regulating valve 102 and a reheater 7 in sequence, and the second branch is provided with a third regulating valve 103. The outlet of the power generation turbine 22 is connected to the heat source side inlet of the high temperature regenerator 31, the heat source side outlet of the high temperature regenerator 31 is connected to the heat source side inlet of the low temperature regenerator 32, and the heat source side outlet of the low temperature regenerator 32 is connected to the inlet of the diverter 5. When working, the supercritical carbon dioxide working medium is filled into various places of the circulation pipeline 100.

[0045] It should be noted that the function of the driving unit 1 is to provide the generator set 2 with high-pressure, high-temperature supercritical carbon dioxide circulating working fluid, and the starter 11 is used to start the rotation of the driving turbine 12 and the main compressor 13 at the initial stage. The function of the generator set 2 is to convert the total enthalpy of the high-pressure, high-temperature supercritical carbon dioxide circulating working fluid into electrical energy, that is, the starter 21 is used to convert the mechanical energy of the power turbine 22 into electrical energy. The precooler 6 is used to reduce the temperature of the working fluid entering the main compressor 13.

[0046] The working principle of the supercritical carbon dioxide cycle power generation system of this embodiment is as follows.

[0047] Before the system is operated, supercritical carbon dioxide (hereinafter referred to as super-II) is charged into various places of the circulation pipeline 100. The starter 11 of the drive unit 1 drives the drive turbine 12 and the main compressor 13 to rotate, and a part of the super-II is compressed in the main compressor 13, and then flows along the system pipeline, passes through the cold source side of the low-temperature regenerator 32 to absorb heat, and is mixed with the super-II at the outlet of the recompressor 23 through the mixer 33, and then enters the cold source side of the high-temperature regenerator 31 to absorb heat, and then enters the main heater 4.

[0048] After that, the super-two working fluid absorbs heat from the main heater 4 and enters the driving turbine 12 for expansion, driving the main compressor 13 to increase speed. After the expanded super-two working fluid is divided by the second regulating valve 102 and the third regulating valve 103, a part of the super-two working fluid enters the reheater 7 through the second regulating valve 102 for further temperature increase, and then enters the power turbine 22 to expand and do work (i.e., generate electricity), while driving the recompressor 23 to rotate. The other part of the working fluid enters the heat source side of the high-temperature regenerator 31 and the heat source side of the low-temperature regenerator 32 for heat recovery after the working fluid expands in the power turbine 22 through the third regulating valve 103.

[0049] Afterwards, the working fluid on the heat source side of the low-temperature regenerator 32 flows to the splitter 5 and is divided into two paths. One path enters the precooler 6 to reduce the working fluid temperature to near the critical point and then is compressed at the main compressor 13. The other path of working fluid enters the re-compressor 23 for compression, and a new power generation cycle is restarted.

[0050] When the system needs to reduce the power generation, the flow of the super-two working fluid in the power turbine 22 is reduced by reducing the opening of the second regulating valve 102 and increasing the opening of the third regulating valve 103. At the same time, the opening of the first regulating valve 101 is increased to increase the flow in the re-compressor 23. In this way, the power output of the power turbine 22 can be reduced, and the power consumption of the re-compressor 23 can be increased, thereby quickly reducing the power generation and reducing the power generated by the all-in-one machine 21. On the other hand, the increased flow of the re-compressor 23 will reduce the flow in the main compressor 13, reduce power consumption, and increase the speed of the driving unit 1 due to the reduced power consumption of the main compressor 13, so that the balance state of the whole system can still be guaranteed. At the same time, the inlet pressure of the main compressor 13 will increase because the super-two working fluid has not been fully expanded by the power turbine 22, so it is not easy to enter the two-phase region, thereby ensuring the stable operation of the driving unit 1 and the generator set 2.

[0051] When the cycle needs to increase the power generation, the opening of the second regulating valve 102 can be increased and the opening of the third regulating valve 103 can be decreased to increase the flow rate of the supercritical two-phase working fluid in the power generation turbine 22. At the same time, the opening of the first regulating valve 101 is decreased to reduce the flow rate in the recompressor 23. In this way, the output work of the power generation turbine 22 can be increased and the power consumption of the recompressor 23 can be reduced, thereby quickly increasing the power generation and increasing the electric energy generated by the integrated starter-generator 21. On the other hand, the reduced flow rate of the generator set 2 will increase the flow rate of the main compressor 13 in the drive unit 1 and increase the power consumption, so the rotational speed of the drive unit 1 will decrease. Therefore, the balance state of the entire system can still be ensured. At the same time, although the inlet pressure of the main compressor 13 will decrease somewhat, it is still higher than the design point pressure, so it is not easy to enter the two-phase region, thus ensuring the stable operation of the drive unit 1 and the generator set 2.

[0052] In summary, the supercritical carbon dioxide cycle power generation system of this embodiment includes a drive unit 1 and a generator set 2, forming a split-shaft layout, decoupling the complex supercritical two-phase system mechanically, thereby increasing the adjustable parameters and making the off-design conditions more flexible.

[0053] In the supercritical carbon dioxide cycle power generation system of this embodiment, when operating under off-design conditions (changing the power generation), it is not necessary to discharge the supercritical two-phase working fluid in the system (i.e., without using the variable volume method), but rather to rely on adjusting the opening degrees of the first, second, and third regulating valves to achieve changes in the output power of the driving turbine 12 and the power generation turbine 22, rather than simply reducing or increasing the system pressure. The rotational speed of the generator set 2 is generally a constant speed, and the rotational speed of the drive unit 1 is adjustable. The increased or decreased power generation is flexibly taken over and adjusted by the drive unit 1 to adapt to and meet the requirements of variable power. During the power regulation process, without discharging or increasing the supercritical two-phase working fluid in the system, the operation stability and efficiency of the system can still be ensured.

[0054] For example, compared with the prior art, when reducing the power generation, the conventional variable volume method is to discharge the supercritical two-phase working fluid in the system to reduce the system pressure, thereby reducing the power generation. The reduction in pressure means that the compressor inlet approaches or even enters the critical point, thus bringing unpredictable system stability problems.

[0055] When the supercritical carbon dioxide cycle power generation system of this embodiment operates under reduced power, it is not necessary to discharge the supercritical two-phase working fluid in the system (i.e., without using the variable volume method), but rather to rely on adjusting the opening degrees of the first, second, and third regulating valves to achieve changes in the output power of the driving turbine 12 and the power generation turbine 22, rather than simply reducing the system pressure. Therefore, the inlet conditions of the main compressor 13 will not enter the critical point, but only remain relatively close to the critical point, so that the power generation regulation of this system can bypass the influence of the critical point of supercritical carbon dioxide, thus ensuring the operation stability and efficiency of the system during the power regulation process.

[0056] In this embodiment, as Figure 1 shown, the supercritical carbon dioxide power generation system may further include a storage tank 8, which stores a carbon dioxide working fluid. The storage tank 8 is connected to the circulation pipeline 100 between the low-temperature recuperator 32 and the inlet of the splitter 5. When the system starts to work, the stored carbon dioxide working fluid (generally supercritical carbon dioxide working fluid) in the storage tank 8 is filled into various parts of the circulation pipeline 100. For the convenience of filling and discharging the supercritical carbon dioxide working fluid in the circulation pipeline 100, the inlet of the storage tank 8 is connected to the circulation pipeline 100 through an inlet valve 81, and the outlet of the storage tank 8 is connected to the circulation pipeline 100 through an outlet valve 82. It should be noted that during the circulation operation, the storage tank 8 and the circulation pipeline 100 are generally kept disconnected. In addition, a pressurizing device may be provided inside the storage tank 8, and the pressurizing device is used to increase the pressure of the carbon dioxide working fluid at the outlet valve 82.

[0057] In this embodiment, as Figure 2 shown, the first regulating valve 101, the second regulating valve 102, and the third regulating valve 103 may be electric regulating valves. And, the supercritical carbon dioxide power generation system may further include a main control device 200, and the main control device 200 is at least communicatively connected to the first regulating valve 101, the second regulating valve 102, and the third regulating valve 103 to adjust the valve opening.

[0058] In this embodiment, as Figure 2 shown, the main control device 200 may be communicatively connected to the main heater 4 and the reheater 7 to control the heating power of the main heater 4 and the reheater 7. At the same time, a working fluid temperature detection sensor or a pressure detection sensor may be provided at the main heater 4, the reheater 7, or other required positions of the circulation pipeline 100 and connected to the main control device 200. The main control device 200 compares the values of the working fluid temperature detection sensor and / or the pressure detection sensor with the desired values, and then adjusts the heating power of the main heater 4 and the reheater 7.

[0059] In addition, the main control device 200 may be communicatively connected to the precooler 6. An inlet temperature detection sensor or an inlet pressure detection sensor may be provided between the precooler 6 and the inlet of the main compressor 13. The main control device 200 may adjust the cooling power of the precooler 6 according to the values of the inlet temperature detection sensor or the inlet pressure detection sensor, so that the inlet conditions of the main compressor 13 do not enter the critical point.

[0060] In this embodiment, as Figure 2 shown, a pressure detection sensor 300 may be provided at the outlet of the driving turbine 12. The pressure detection sensor 300 is communicatively connected to the main control device 200, and the main control device 200 regulates the heating power of the main heater 4 according to the pressure information of the pressure detection sensor 300.

[0061] As Figure 3 shown, an embodiment of the present application further provides a power regulation method for a supercritical carbon dioxide cycle power generation system as described above, including:

[0062] S1. Determine the real-time power generation power W before power regulation m ;

[0063] S2. Determine the target power generation power W after regulation t ;

[0064] S3. Based on the magnitude difference between the target power generation power W t and the real-time power generation power W before regulation m , adjust the opening degrees of the first regulating valve 101, the second regulating valve 102, and the third regulating valve 103.

[0065] Among them, in step S1, some power detection sensors can be added to the generator set 2 to determine the real-time power generation power W before power regulation m , or it can be obtained by manual measurement. In step S2, the target power generation power W t is the expected value of the power generation power after the power needs to be reduced or increased, and is determined according to the actual situation.

[0066] In this embodiment, in step S3, based on the magnitude difference between the target power generation power W t and the real-time power generation power W before regulation m , the step of adjusting the opening degrees of the first regulating valve 101, the second regulating valve 102, and the third regulating valve 103 may include:

[0067] S31. Determine the power difference ΔW between the target power generation power W t and the real-time power generation power W before regulation m ; t-m ;

[0068] S32. Judge whether the absolute value of the power difference ΔW t-m is less than or equal to the first preset difference; if so, go to step S33; if not, go to step S34;

[0069] S33. Keep the current opening degrees of the first regulating valve 101, the second regulating valve 102, and the third regulating valve 103 unchanged;

[0070] S34. Judge whether the target power generation power W t is less than the real-time power generation power W before regulation m ; if W t is less than W m , go to step S35; if W t is greater than Wm , then proceed to step S36;

[0071] S35, W t is less than W m , that is, it is necessary to reduce the power generation. Adjust the opening of the second regulating valve 102 smaller, the opening of the third regulating valve 103 larger, and the opening of the first regulating valve 101 larger according to the preset unit opening measurement;

[0072] S36, W t is greater than W m , that is, it is necessary to increase the power generation. Adjust the opening of the second regulating valve 102 larger, the opening of the third regulating valve 103 smaller, and the opening of the first regulating valve 101 smaller according to the preset unit opening measurement;

[0073] S37. Determine the adjusted real-time power generation W a , and determine whether the absolute value of the difference between the adjusted real-time power generation W a and the target power generation W t is less than or equal to the second preset difference; if so, complete the adjustment of the openings of the first regulating valve 101, the second regulating valve 102, and the third regulating valve 103; if not, repeat steps S35 and S37, or repeat steps S36 and S37.

[0074] Among them, it should be noted that the first preset difference is determined according to the actual situation of reducing or increasing the power generation. Since it may be difficult to achieve exactly the same numerical value in power adjustment, this value represents the allowable consistency error range between the adjusted target power generation W t and the real-time power generation W before adjustment m . The absolute value of the difference between the target power generation W t and the real-time power generation W before adjustment m does not exceed the first preset difference, indicating that no power adjustment is required. The absolute value of the difference between the target power generation W t and the real-time power generation W before adjustment m exceeds the first preset difference, indicating that power adjustment is required.

[0075] In addition, it should be noted that the setting of the second preset difference is similar to that of the first preset difference. Since the finally adjusted real-time power generation W a may be difficult to achieve exactly the same numerical value as the target power generation W t , therefore, this value represents the allowable consistency error range between the adjusted real-time power generation W a and the target power generation W t . The target power generation W t and the adjusted real-time power generation W aThe absolute value of the difference does not exceed the second preset difference, indicating that the power adjustment is completed. The target power generation is W t and the adjusted real-time power generation W a The absolute value of the difference exceeds the second preset difference, indicating that the power adjustment is not completed and further adjustment is required.

[0076] The preset unit opening measure in steps S35 and S36 can be set according to the actual structure of the valve and the actual adjustment requirements. However, it should be noted that the value of the preset unit opening measure should not be too large to avoid excessive adjustment and over-adjustment of the power.

[0077] In this embodiment, before step S3, it may further include: S03, obtaining the outlet pressure P0 of the drive turbine 12 before the adjustment of the regulating valve. After step S3, it further includes:

[0078] S4, obtaining the outlet pressure P of the drive turbine 12 after the adjustment of the regulating valve t ;

[0079] S5, judging whether the absolute value of the difference between the outlet pressure P t and the outlet pressure P0 is less than or equal to the preset pressure difference; if so, keep the current heating power of the main heater 4 unchanged; if not, adjust the heating power of the main heater 4 and repeat steps S4 to S5 until the difference between the outlet pressure P t and the outlet pressure P0 is controlled within the predetermined difference range.

[0080] For example, when reducing the power generation, the increased flow rate of the recompressor 23 will cause the flow rate in the main compressor 13 to decrease and the power consumption to decrease. Since the flow rate of the supercritical working fluid in the main compressor 13 increases, the speed of the drive unit 1 increases (the inlet temperature of the drive turbine 12 remains basically unchanged), so it is still in a balanced state. And subsequently, by controlling the heat added by the main heater 4, the overall speed of the drive unit 1 can be controlled to maintain the outlet pressure of the drive turbine 12 unchanged.

[0081] The above are only the preferred embodiments of the present application and are not used to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A supercritical carbon dioxide power generation system, characterized in that, It comprises a circulation pipeline (100) and a driving unit (1), a generator unit (2), a regenerator assembly (3), a main heater (4), a flow divider (5), a precooler (6) and a reheater (7) arranged in the circulation pipeline (100); The regenerator assembly (3) comprises a high-temperature regenerator (31), a low-temperature regenerator (32) and a flow mixer (33); The driving unit (1) comprises a starter (11), and a driving turbine (12) and a main compressor (13) driven by the starter (11); The generator set (2) comprises an integrated initiator (21), and a power generation turbine (22) and a recompressor (23) drivingly connected to the integrated initiator (21); The two outlets of the flow splitter (5) are respectively connected to the inlet of the main compressor (13) and the inlet of the re-compressor (23); the pre-cooler (6) is arranged between the flow splitter (5) and the main compressor (13); and a first regulating valve (101) is arranged between the flow splitter (5) and the re-compressor (23); The outlet of the main compressor (13) is connected to the cold source side inlet of the low-temperature regenerator (32), and the cold source side outlet of the low-temperature regenerator (32) and the outlet of the recompressor (23) are respectively connected to the two inlets of the mixer (33); the outlet of the mixer (33) is connected to the cold source side inlet of the high-temperature regenerator (31), and the cold source side outlet of the high-temperature regenerator (31) is connected to the inlet of the main heater (4), and the outlet of the main heater (4) is connected to the inlet of the driving turbine (12); The outlet of the driving turbine (12) is divided into a first branch and a second branch, the first branch is connected to the inlet of the power generation turbine (22), the second branch is connected to the heat source side inlet of the high-temperature regenerator (31), a second regulating valve (102) and the reheater (7) are sequentially arranged on the first branch, and a third regulating valve (103) is arranged on the second branch; The outlet of the power generation turbine (22) is connected to the heat source side inlet of the high-temperature heat regenerator (31), the heat source side outlet of the high-temperature heat regenerator (31) is connected to the heat source side inlet of the low-temperature heat regenerator (32), and the heat source side outlet of the low-temperature heat regenerator (32) is connected to the inlet of the diverter (5); During operation, supercritical carbon dioxide working fluid is filled into various locations of the circulation pipeline (100); Among them, the real-time power generation power of the generator set (2) before adjusting the power is W m , the set target power generation power is W t , a first preset difference is set, a second preset difference is set, and the real-time power generation power after adjusting the power is W a , then the opening adjustment steps of the first, second, and third regulating valves include: Determine the real-time power generation W m and the target power generation W t for the power difference W t-m ; Determine the power difference W t-m If the absolute value of the power difference is less than or equal to the first preset difference, then keep the opening degrees of the first, second, and third regulating valves unchanged; Determine the power difference W t-m If the absolute value of is greater than the first preset difference, adjust the opening degrees of the first, second, and third regulating valves until the real-time power generation power W a after adjustment and the target power generation power W t The absolute value of the difference is less than or equal to the second preset difference.

2. The supercritical carbon dioxide cycle power generation system according to claim 1, wherein It comprises a storage tank (8) storing carbon dioxide as a working medium, wherein the storage tank (8) is connected to the circulation pipeline (100) between the low-temperature regenerator (32) and the inlet of the splitter (5).

3. The supercritical carbon dioxide cycle power generation system according to claim 2, characterized in that The inlet of the storage tank (8) is connected to the circulation pipeline (100) through an inlet valve (81), and the outlet of the storage tank (8) is connected to the circulation pipeline (100) through an outlet valve (82).

4. The supercritical carbon dioxide cycle power generation system according to claim 3, wherein A pressure boosting device is provided in the storage tank (8), and the pressure boosting device is used to increase the pressure of the carbon dioxide working fluid of the outlet valve (82).

5. The supercritical carbon dioxide cycle power generation system according to claim 1, characterized in that The first regulating valve (101), the second regulating valve (102) and the third regulating valve (103) are electric regulating valves; The supercritical carbon dioxide power generation system includes a main control device (200), and the main control device (200) is communicatively connected to at least the first regulating valve (101), the second regulating valve (102), and the third regulating valve (103) to adjust the valve opening degree.

6. The supercritical carbon dioxide cycle power generation system according to claim 5, wherein, The main control device (200) is communicatively connected to the main heater (4) and the reheater (7) to control the heating power of the main heater (4) and the reheater (7).

7. The supercritical carbon dioxide cycle power generation system according to claim 6, wherein A pressure detection sensor (300) is provided at the outlet of the driving turbine (12), the pressure detection sensor (300) is communicatively connected to the main control device (200), and the main control device (200) adjusts the heating power of the main heater (4) according to the pressure information of the pressure detection sensor (300).

8. A power regulation method for a supercritical carbon dioxide cycle power generation system according to any one of claims 1 to 7, characterized in that, Including: S1. Determine the real-time power generation power W before adjusting the power m ; S2. Determine the adjusted target power generation W t ; S3. Based on the target power generation W t and the magnitude difference from the real-time power generation W m before adjustment, adjust the opening degrees of the first regulating valve (101), the second regulating valve (102), and the third regulating valve (103).

9. The power adjustment method according to claim 8, wherein In step S3, based on the target power generation W t and the real-time power generation W before adjustment m The steps of adjusting the opening degrees of the first regulating valve (101), the second regulating valve (102) and the third regulating valve (103) according to the magnitude difference include: S31. Determine the target power generation W t and the power difference W m from the real-time power generation W t-m before adjustment; S32. Determine the power difference W t-m Check if the absolute value of the power difference is less than or equal to a first preset difference. If so, proceed to step S33; if not, proceed to step S34. S33. Keep the current opening degrees of the first regulating valve (101), the second regulating valve (102), and the third regulating valve (103) unchanged; S34. Determine the target power generation W t Is it less than the real-time power generation W before regulation? m If W t is less than W m , then go to step S35; if W t is greater than W m , then go to step S36; S35. Adjust the opening degree of the second regulating valve (102) downwards, adjust the opening degree of the third regulating valve (103) upwards, and adjust the opening degree of the first regulating valve (101) upwards according to a preset unit opening measure; S36. Adjust the opening degree of the second regulating valve (102) upwards, adjust the opening degree of the third regulating valve (103) downwards, and adjust the opening degree of the first regulating valve (101) downwards according to a preset unit opening measure; S37. Determine the adjusted real-time power generation W a , and determine whether the absolute value of the difference between the adjusted real-time power generation W a and the target power generation W t is less than or equal to a second preset difference; if so, complete the opening adjustment of the first regulating valve (101), the second regulating valve (102) and the third regulating valve (103); if not, repeat steps S35 and S37, or repeat steps S36 and S37.

10. The power adjustment method according to claim 8, characterized in that, Before step S3, it further includes: S03. Obtain the outlet pressure P0 of the driving turbine (12) before the regulating valve is adjusted; After step S3, it further includes: S4. Obtain the outlet pressure P of the drive turbine (12) after the regulating valve is adjusted t ; S5. Determine the outlet pressure P t Whether the absolute value of the difference from the outlet pressure P0 is less than or equal to a preset pressure difference; if so, keep the current heating power of the main heater (4) unchanged; if not, adjust the heating power of the main heater (4), and repeat steps S4 to S5 until the outlet pressure P t The difference from the outlet pressure P0 is controlled within a predetermined difference range.

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