Waste heat driven S-CO2 power cycle operation method and system

Abstract

The invention provides an operation method of an S-CO2 power cycle system driven by waste heat, which belongs to the field of waste heat utilization and power generation and comprises the following steps: CO2 filling: filling a system working medium into a storage tank through an injection pipeline; the system is started and runs under variable working conditions, the environment temperature is lower than the normal working temperature, the cooling water flow is adjusted, liquid CO2 is formed at an output port of a cooler and separated into a storage tank, when the load needs to be increased, a waste heat valve of a waste heat pipeline is opened, the CO2 flow is increased, and when the load needs to be reduced, the waste heat valve of the waste heat pipeline is opened, the CO2 flow is reduced, and the CO2 flow is reduced. Storage tank cold tracing keeps the inlet pressure of the first compressor constant; when the environment temperature is low, the cooling water flow is adjusted, and then the system temperature, pressure and flow are rapidly adjusted, so that CO2 at an inlet of the compressor is effectively prevented from being in a liquid state, and rapid response of the system under variable working conditions is achieved.

Description

Technical Field

[0001] The invention belongs to the field of waste heat utilization and power generation, and in particular relates to a waste heat driven S-CO2 power cycle operation method and system. Background Art

[0002] The S-CO2 power cycle is considered to be the most promising power generation cycle in the future due to its small size and high efficiency, and is expected to replace the water vapor Rankine cycle. Therefore, in the field of waste heat recovery, the S-CO2 power cycle has been widely used.

[0003] In the existing technical solutions, more attention is paid to the improvement of the internal structure of the cycle, so as to improve the system performance and energy utilization, or to the coordinated control method of the system variable load operation to adapt to the changes of intermittent renewable energy such as wind power and solar energy. However, from a practical point of view, a very important component of the S-CO2 power cycle is the working fluid. The filling and recovery of the working fluid and the change of the working fluid flow rate during operation are crucial to the research of the S-CO2 power cycle. The CO2 power cycle has high pressure and a large amount of CO2 filling required. How to safely and quickly fill CO2 into the power system and recover CO2 from the power system has not yet been determined. In addition, for the case of variable load operation, due to the fluctuation of ambient temperature, the cooling water temperature changes greatly. How to prevent the CO2 at the compressor inlet from being in a liquid state is a problem that must be solved. At the same time, the fluctuation of the flue gas waste heat flow temperature will also directly affect the safety of the system. How to quickly and efficiently complete the regulation of the circulating working fluid flow is also a problem that needs to be considered. Summary of the invention

[0004] In view of the above problems, the present invention proposes an operation method of a waste heat driven S-CO2 power cycle system, comprising the following steps:

[0005] CO2 filling, filling the system working fluid into the storage tank through the injection pipeline;

[0006] The system starts, opens the main compression circuit and the waste heat pipeline, controls the working fluid in the storage tank to the preset temperature and the working fluid in the main compression circuit to the preset pressure; opens the first throttle valve, and after the working fluid reaches the preset pressure, starts the high-pressure turbine;

[0007] During variable operating conditions, the load is increased, the fifteenth valve of the waste heat pipeline is opened wider, the working fluid flow is increased, and the storage tank is heated to keep the inlet pressure of the first compressor constant; the load is reduced, the fifteenth valve of the waste heat pipeline is opened narrower, the CO2 flow is reduced, and the storage tank is cooled to keep the inlet pressure of the first compressor constant; when the ambient temperature is lower than the normal operating temperature, the cooling water flow is adjusted, liquid CO2 is formed at the output port of the cooler, separated to the storage tank through the separator, and the heat pump refrigerator heats the CO2 in the storage tank.

[0008] Specifically, the CO2 filling is performed by injecting the system working fluid into the storage tank in the form of gas-liquid alternating injection through the injection pipeline.

[0009] Specifically, the CO2 filling into the storage tank in the form of gas-liquid alternating injection through the injection pipeline includes the following steps:

[0010] Gaseous CO2 filling is achieved by opening the first valve and the sixth valve and closing the second valve, the fifth valve and the third valve;

[0011] After the storage tank reaches the predetermined pressure, the second valve is closed and the fourth valve is opened, so that CO2 can continue to be filled through the primary pump to increase the pressure;

[0012] After the storage tank reaches the set pressure, liquid CO2 is filled by closing the third valve and opening the sixth valve;

[0013] When the liquid CO2 in the storage tank exceeds the specified value, the gaseous CO2 is filled by closing the sixth valve and opening the third valve;

[0014] When the pressure in the storage tank exceeds a predetermined value, the fourth valve is closed and the fifth valve is opened to increase the pressure of the primary pump and the secondary pump simultaneously to complete the CO2 filling.

[0015] Specifically, the system startup includes the following steps:

[0016] Open the cooler to allow the cooling water to circulate.

[0017] The first compressor is started to allow the CO2 in the storage tank to enter the first compressor for compression after passing through the eighth valve and the separator, and the compressed CO2 is heated by the first regenerator, the second regenerator and the first heater of the third pipeline in sequence;

[0018] Close the ninth valve to hold the pressure, and when the pressure gradually reaches the preset pressure, open the ninth valve, and CO2 enters the first throttle valve through the ninth valve for throttling;

[0019] Open the fifteenth valve to allow the first heater to utilize waste heat to heat CO2 and start the high-pressure turbine.

[0020] Specifically, the system startup further includes the following steps:

[0021] After the first compressor is turned on, the first anti-surge valve is opened.

[0022] Specifically, the variable operating condition operation and load increase include the following steps:

[0023] Open the fifteenth and seventeenth valves, and at the same time open the eighth valve;

[0024] Start the heat pump refrigerator to heat the storage tank, so that CO2 flows into the main compression circuit and the inlet pressure of the first compressor remains unchanged;

[0025] When the inlet pressure of the first compressor reaches the preset pressure, the eighth valve is closed to make the system operate normally, and at the same time, the heat pump refrigerator is turned off to stop heating.

[0026] Specifically, the variable operating condition operation and load reduction include the following steps:

[0027] Close the 15th and 17th valves, and open the 8th valve;

[0028] Start the heat pump refrigerator to cool the storage tank, so that the CO2 in the main pressure circuit flows into the storage tank, and the inlet pressure of the first compressor remains unchanged;

[0029] After the system runs stably, close the eighth valve and simultaneously turn off the heat pump refrigerator to stop refrigeration.

[0030] Specifically, the variable operating condition operation, in which the ambient temperature is lower than the normal operating temperature, comprises the following steps:

[0031] Adjust the cooling water flow in the cooler so that the CO2 at the inlet of the first compressor is in gaseous state.

[0032] When the CO2 at the cooler outlet is in liquid state, it is separated into gas and liquid through a separator.

[0033] Open the eighth valve to store liquid CO2 into the storage tank;

[0034] Start the heat pump refrigerator to heat the storage tank, increase the inlet temperature of the first compressor, and reduce the formation of liquid CO2.

[0035] Specifically, the following steps are also included:

[0036] The system is shut down, and the fifteenth and seventeenth valves of the waste heat pipeline are gradually closed to reduce the waste heat, reduce the frequency and output pressure of the first compressor, and decouple the high-pressure turbine; the first throttle valve is bypassed, the storage tank is refrigerated to stabilize the inlet pressure of the first compressor, the first compressor is stopped, and the cooling water is turned off.

[0037] Specifically, the following steps are also included:

[0038] During system maintenance, CO2 is discharged, the storage tank is refrigerated, and the liquid CO2 is discharged into the CO2 Dewar tank; after the liquid CO2 is discharged, the storage tank is heated, and the gaseous CO2 is discharged into the CO2 Dewar tank, and a CO2 booster is used to press the system's gaseous CO2 into the CO2 Dewar tank until the gaseous CO2 is emptied.

[0039] A waste heat driven S-CO2 power cycle system, comprising a CO2 tanker, an injection pipeline, a storage tank, a main compression circuit, a first heater, a high pressure turbine, a waste heat pipeline and a separator;

[0040] The input port of the injection pipeline is connected to the CO2 tank truck, and the outlet of the injection pipeline is connected to the injection port of the storage tank;

[0041] The first inlet of the separator is connected to the output port of the storage tank;

[0042] The main compression circuit input port is connected to the first outlet of the separator, and the main compression circuit output port is connected to the second inlet of the separator; the working fluid at the main compression circuit output port is first heated by the expanded CO2 exhaust gas, and then heated by the waste heat pipeline for a second time, and then the high-temperature CO2 enters the high-pressure turbine to expand and perform work;

[0043] The main compression circuit includes a first heater and a high-pressure turbine, and the first heater is close to the main compression circuit input port; the high-pressure turbine is close to the main compression circuit output port;

[0044] The waste heat pipeline is in communication with the waste heat flow side of the first heater and is used for conveying waste heat to the first heater to heat the working medium flowing through the first heater.

[0045] Specifically, a heat pump refrigerator is arranged outside the storage tank, and the heat pump refrigerator is used to control the internal temperature of the storage tank.

[0046] Specifically, the main compression circuit comprises:

[0047] a third pipeline, wherein the input port of the third pipeline is connected to the output port of the separator, a first compressor, a first regulating valve, a high-pressure turbine and a first check valve are sequentially arranged from the input port to the output port of the third pipeline, and an input port of a tenth valve is connected to the output port end of the third pipeline;

[0048] The first pipeline of the first heat regenerator, the first pipeline of the second heat regenerator, and the first pipeline of the first heater are connected in sequence at a position between the first compressor and the first regulating valve of the third pipeline, and the first heat regenerator is located near the outlet of the first compressor;

[0049] a fourth pipeline, wherein the input port of the fourth pipeline is connected to the output port of the tenth valve, and the output port of the fourth pipeline is sequentially connected to the heat dissipation pipeline of the second heat regenerator and the heat dissipation pipeline of the first heat regenerator;

[0050] The second pipeline, the second pipeline input port is connected with the fourth pipeline output port, and the second pipeline output port is connected with the circulation inlet of the separator; the twentieth valve and the cooler are sequentially arranged from the input port to the output port of the second pipeline.

[0051] Specifically, the waste heat pipeline includes:

[0052] a first waste heat pipeline, wherein the output port of the first waste heat pipeline is connected to the second pipeline inlet of the first heater; and a fifteenth valve is arranged on the first waste heat pipeline;

[0053] A second waste heat pipeline, wherein an input port of the second waste heat pipeline is connected to a first pipeline outlet of the first heater, and an output port of the second waste heat pipeline is connected to the outside.

[0054] Specifically, the system further includes a second compression circuit, wherein the second compression circuit includes:

[0055] a fifth pipeline, wherein the input port of the fifth pipeline is connected to the output port of the fourth pipeline, and the input port of the fifth pipeline is connected to the input port of the twentieth valve, and the output port of the fifth pipeline is connected to the output port end of the second heat regenerator,

[0056] The fifth pipeline is provided with an eleventh valve, a second compressor, a thirteenth valve, a second regulating valve, a low-pressure turbine and a second check valve in sequence from the input port to the output port; the outlet of the second check valve is connected between the second pipeline of the first regenerator and the second pipeline of the second regenerator;

[0057] A second pipeline having a second heater is connected between the second compressor of the fifth pipeline and the thirteenth valve;

[0058] The medium pipeline of the second heater is communicated with the fifth pipeline, and the waste heat pipeline of the second heater is communicated with the second waste heat pipeline.

[0059] Specifically, the system further includes a CO2 discharge module, and the CO2 discharge module includes:

[0060] A first discharge pipe, wherein the input port end of the first discharge pipe is connected to the storage tank, the output port end of the first discharge pipe is connected to the CO2 Dewar tank, and an eighteenth valve is provided on the first discharge pipe;

[0061] A second discharge pipe, wherein the input port end of the second discharge pipe is connected to the input port end of the eighteenth valve, the output port end of the second discharge pipe is connected to the CO2 Dewar tank, and the nineteenth valve and the CO2 booster are sequentially arranged on the second discharge pipe;

[0062] The CO2 Dewar tank is connected with a refrigerator.

[0063] Beneficial effects:

[0064] 1. In the present invention, when the load needs to be increased, the waste heat valve of the waste heat pipeline is opened wide to increase the CO2 flow rate, and the storage tank is heated to keep the first compressor inlet pressure constant; when the load needs to be reduced, the waste heat valve of the waste heat pipeline is opened small to reduce the CO2 flow rate, and the storage tank is cooled to keep the first compressor inlet pressure constant; when the ambient temperature is low, the cooling water flow rate is adjusted, and liquid CO2 is formed at the output port of the cooler and separated to the storage tank, and the heat pump refrigerator is appropriately heated, thereby realizing rapid adjustment of system temperature, pressure and flow, thereby effectively preventing the compressor inlet CO2 from being in liquid state, and realizing rapid response of the system under variable working conditions.

[0065] 2. The present invention sets a CO2 discharge module and starts a heat pump refrigerator to cool the storage tank, maintains the temperature of the storage tank at about 5°C, and makes the supercritical CO2 form a liquid in the storage tank, while the system pressure drops. Afterwards, the liquid CO2 in the storage tank is discharged into the CO2 dewar tank through the eighteenth valve by using the pressure difference. When the liquid is almost discharged, in order to discharge the gaseous CO2 as much as possible, the heat pump refrigerator can be started to heat the storage tank appropriately to increase the system pressure, so as to maximize the recovery of the gaseous CO2 into the CO2 dewar tank through the eighteenth valve through the pressure difference, which can realize the recycling of CO2 to a great extent, thereby reducing the waste of working fluid and the safety risks and environmental pollution caused by the large-scale and direct discharge of CO2 into the environment.

[0066] 3. The present invention is connected to the CO2 tank truck through the input port of the injection pipeline, and the outlet of the injection pipeline is connected to the injection port of the storage tank; the injection pipeline can inject the working fluid in the CO2 tank truck into the storage tank in gaseous or liquid state; it can effectively realize the safe and rapid filling of CO2 in the S-CO2 power cycle system.

[0067] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0069] Figure 1 This is a basic flow chart for the charging, startup and operation process of the S-CO2 power cycle system.

[0070] Figure 2This is the basic flow chart of the shutdown process of the S-CO2 power cycle system.

[0071] Figure 3 Basic flow chart of CO2 exhaust process for S-CO2 system maintenance.

[0072] Figure 4 Structural diagram of the S-CO2 power cycle system driven by waste heat.

[0073] Figure 5 This is the structural diagram of the heating and cooling storage tank.

[0074] Figure 6 This is the system structure diagram of the maintenance process.

[0075] In the figure, 1, CO2 tank truck; 2, first valve; 3, second valve; 4, flow meter; 5, third valve; 6, gasifier; 7, primary pump; 8, fourth valve; 9, fifth valve; 10, secondary pump; 11, sixth valve; 12, seventh valve;

[0076] 13. Storage tank; 14. Eighth valve; 15. Separator; 16. First compressor; 17. First anti-surge valve; 18. First regenerator; 19. Second regenerator; 20. First heater; 21. Ninth valve; 22. First throttle valve; 23. First check valve; 24. Tenth valve; 25. Second check valve; 26. Eleventh valve; 27. Second compressor; 28. Second anti-surge valve; 29. ​​Second heater; 30. Twelfth valve; 31. Second throttle valve; 32. 1st regulating valve; 33, high pressure turbine; 34, 13th valve; 35, 2nd regulating valve; 36, low pressure turbine; 37, safety valve; 38, 14th valve; 39, 15th valve; 40, 16th valve; 41, 17th valve; 42, control cabinet; 43, gas discharge valve; 44, 18th valve; 45, CO2 dewar tank; 46, chiller; 47, 19th valve; 48, CO2 booster; 49, 20th valve; 50, cooler; 201, heat pump refrigeration machine;

[0077] 101, first pipeline; 102, second pipeline; 103, third pipeline; 104, fourth pipeline; 105, fifth pipeline;

[0078] 301, first branch road; 302, second branch road; 303, third branch road; 304, fourth branch road; 305, fifth branch road;

[0079] 401, the first anti-asthma branch; 402, the second anti-asthma branch;

[0080] 501, a first waste heat pipeline; 502, a second waste heat pipeline;

[0081] 601, first discharge pipe; 602, second discharge pipe. DETAILED DESCRIPTION

[0082] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0083] Embodiment 1,

[0084] like Figure 1 As shown, Figure 1 This is a basic flow chart of the charging, startup and operation process of the S-CO2 power cycle system. Figure 1 , a method for operating a waste heat driven S-CO2 power cycle system, comprising the following steps:

[0085] S1: CO2 filling, filling the storage tank 13 with the system working fluid in the form of gas-liquid alternating injection through the injection pipeline; specifically, according to the system design working conditions and component design, the system CO2 filling amount is estimated, and the system working fluid is filled in the form of gas-liquid alternating injection through the injection pipeline;

[0086] The steps include:

[0087] Gaseous CO2 filling is achieved by opening the first valve 2 and the sixth valve 11, and closing the second valve 3, the fifth valve 9 and the third valve 5;

[0088] After the storage tank 13 reaches a predetermined pressure, the CO2 is continuously filled by increasing the pressure through the primary pump 7 by closing the second valve 3 and opening the fourth valve 8;

[0089] After the storage tank 13 reaches the set pressure, liquid CO2 is filled by closing the third valve 5 and opening the sixth valve 11;

[0090] When the liquid CO2 in the storage tank 13 exceeds the specified value, the gaseous CO2 is filled by closing the sixth valve 11 and opening the third valve 5;

[0091] When the pressure in the storage tank 13 exceeds a predetermined value, the fourth valve 8 is closed and the fifth valve 9 is opened so that the primary pump 7 and the secondary pump 10 are simultaneously pressurized to complete CO2 filling.

[0092] S2: The system starts, and the working medium in the filled storage tank 13 is heated or cooled to a preset temperature, which is the optimal operating temperature of the working medium, and the inlet of the first compressor 16 reaches a preset pressure (the preset pressure is the optimal operating pressure of the first compressor 16); the first throttle valve 22 is opened, and a preliminary circulation is established to make the working medium reach a predetermined pressure (the predetermined pressure is the optimal operating pressure of the equipment). Specifically, the main compression circuit and the waste heat pipeline are opened, and the filled storage tank 13 is cooled and heated to stabilize the inlet pressure of the first compressor 16 and circulate the working medium; the first throttle valve 22 is opened, and a preliminary circulation is established and the valve of the waste heat pipeline is gradually opened to achieve the rush adjustment to open the high-pressure turbine 33. The cooling and heating are cooling and heating;

[0093] The steps include:

[0094] The cooler 50 is turned on to allow the cooling water to circulate, and the first compressor 16 is started to allow the CO2 in the storage tank 13 to enter the first compressor 16 through the eighth valve 14 and the separator 15 for compression. The compressed CO2 is heated by the first regenerator 18, the second regenerator 19 and the first heater 20 of the third pipeline 103 in sequence. The ninth valve 21 is closed to hold the pressure, and when the pressure gradually reaches the predetermined pressure, the ninth valve 21 is opened, and the CO2 enters the first throttle valve 22 through the ninth valve 21 for throttling.

[0095] The fifteenth valve 39 is opened to allow the first heater 20 to heat CO2 with waste heat and to start the high pressure turbine 33. After the first compressor 16 is started, the first anti-surge valve 17 is opened.

[0096] S3: Variable operating conditions: increase the load, open the waste heat valve of the waste heat pipeline to increase the CO2 flow rate, and heat the storage tank 13 to keep the inlet pressure of the first compressor 16 constant; reduce the load, open the waste heat valve of the waste heat pipeline to reduce the CO2 flow rate, and cool the storage tank 13 to keep the inlet pressure of the first compressor 16 constant; when the ambient temperature is low, adjust the cooling water flow rate, and form liquid CO2 at the output port of the cooler 50 to separate it into the storage tank 13, and heat the heat pump refrigerator 201 appropriately.

[0097] Specifically, during the variable operating condition operation, when the load increases, the fifteenth valve 39 and the seventeenth valve 41 for controlling the waste heat flow are opened, and the inlet and outlet eighth valve 14 of the storage tank 13 connecting the system is opened, and the heat pump refrigeration machine 201 is started to heat the storage tank 13 appropriately, so that CO2 can flow into the system, and the inlet pressure of the first compressor 16 remains basically unchanged. When the non-design load steady state is reached, the eighth valve 14 is closed to make the system operate normally, and the heat pump refrigeration machine 201 is closed to stop heating. When the load decreases, the fifteenth valve 39 and the seventeenth valve 41 for controlling the waste heat flow are opened, and the temperature of the storage tank 13 is appropriately reduced. The inlet and outlet eighth valve 14 of the storage tank 13 connecting the system is opened, and the heat pump refrigeration machine 201 is started to cool the storage tank 13 appropriately, so that CO2 in the system can flow into the storage tank 13, so as to keep the inlet pressure of the first compressor 16 unchanged. After the system runs stably, the eighth valve 14 is closed, and the heat pump refrigeration machine 201 is closed to stop cooling. When the ambient temperature is low, the cooling water temperature is low, and the entire cooling process can be adjusted by adjusting the cooling water flow in the cooler 50, so that the CO2 at the inlet of the first compressor 16 is gaseous. When the CO2 at the outlet of the cooler 50 is liquid, the fluid passes through the separator 15 for gas-liquid separation, and at the same time, the eighth inlet and outlet valve 14 of the Unicom system on the storage tank 13 is opened to store the liquid CO2 in the storage tank 13. At this time, the heat pump refrigerator 201 can be started to heat the storage tank 13 appropriately to appropriately increase the inlet temperature of the first compressor 16 and reduce the formation of liquid CO2.

[0098] S4: The system is shut down, the waste heat valve of the waste heat pipeline is gradually closed to reduce the waste heat, the frequency and output pressure of the first compressor 16 are reduced, and the turbine unit is decoupled; the first throttle valve 22 is bypassed, the storage tank 13 is cooled to stabilize the inlet pressure of the first compressor 16, the first compressor 16 is stopped, and the cooling water is turned off.

[0099] During shutdown (ref. Figure 2 ), first close the waste heat pipeline, close the fifteenth valve 39 and the seventeenth valve 41, detect the pressure and temperature of CO2 at the inlet of the high-pressure turbine 33 and the low-pressure turbine 36, and disconnect the high-pressure turbine 33 from the system, and at the same time open the eighth inlet and outlet valve 14 on the storage tank 13 that connects the system, start the heat pump refrigerator 201 to properly cool the storage tank 13, so that the CO2 in the system can flow into the storage tank 13, and reduce the CO2 flow in the system. When it is impossible to flush, open the ninth valve 21 and the twelfth valve 30, start the first throttle valve 22 and the second throttle valve 31, and then gradually reduce the CO2 flow through the first compressor 16 and the second compressor 27. When the minimum flow is reached, stop the operation of the first compressor 16 and the second compressor 27, and at the same time turn off the cooling water of the cooler 50.

[0100] S5: When the system is inspected and CO2 is discharged (refer to Figure 3 ), the storage tank 13 is refrigerated, and the liquid CO2 is discharged into the CO2 Dewar tank 45 until the liquid CO2 can no longer be discharged; the storage tank 13 is heated, and the gaseous CO2 is discharged into the CO2 Dewar tank 45, and the CO2 booster 48 is used to press the gaseous CO2 into the external Dewar tank 45 until the gaseous CO2 is emptied.

[0101] Example 2

[0102] like Figure 4 As shown, Figure 4 The structure diagram of the S-CO2 power cycle system driven by waste heat. Figure 4 A waste heat driven S-CO2 power cycle system, comprising a CO2 tanker 1, an injection pipeline, a storage tank 13, a main compression circuit, a first heater 20, a high pressure turbine 33, a waste heat pipeline, a separator 15 and a control cabinet 42, wherein the input port of the injection pipeline is connected to the CO2 tanker 1, and the outlet of the injection pipeline is connected to the injection port of the storage tank 13; the injection pipeline can inject the working medium in the CO2 tanker 1 into the storage tank 13 in a gaseous or liquid state; the first inlet of the separator 15 is connected to the output port of the storage tank 13, and the first inlet is an injection port for receiving The working fluid injected from the storage tank 13; the main compression loop input port is connected to the first outlet of the separator 15, the first outlet is the gas outlet, the main compression loop output port is connected to the medium flow side of the separator 15, and the second inlet port is the input port; and the main compression loop is located on the side of the separator 15 away from the injection pipeline; the main compression loop is used to circulate CO2 to drive the high-pressure turbine 33 to do work; the working fluid at the main compression loop output port is first heated by the expanded CO2 exhaust gas, and then heated for the second time by the waste heat pipeline, and then the high-temperature CO2 enters the high-pressure turbine 33 to expand and do work;

[0103] The medium flow side between the main compression circuit and the first heater 20, the first heater 20 is located near the main compression circuit input port; the first pipeline of the first heater 20 is a working medium passing pipeline, and the second pipeline is a waste heat passing pipeline;

[0104] The high-pressure turbine 33 is connected to the main compression circuit, and the high-pressure turbine 33 is located at the outlet end of the first pipeline of the first heater 20;

[0105] The waste heat pipeline is connected to the waste heat flow side of the first heater 20, and is used to transport waste heat to the first heater 20 to heat the working medium flowing through the first heater 20; the working medium is CO2; the main compression circuit is connected to the output port of the storage tank 13, and the first heater 20 is provided on the main compression circuit, and the first heater 20 is used to heat the working medium in the main compression circuit. The first heater 20 is a high-temperature heater. The waste heat pipeline is connected to the waste heat pipeline of the first heater 20, and is used to transport waste heat to the first heater 20 to heat the working medium flowing through the first heater 20.

[0106] Specifically, the first heater 20 has two groups of pipes, one group is the working fluid flow pipe (i.e., the first pipe), which is used for the circulation of the working fluid, and the other group is the waste heat connecting pipe (i.e., the second pipe), which is used to connect the first waste heat pipe 501 and the second waste heat pipe 502, and use waste heat to heat the working fluid.

[0107] The control cabinet 42 is connected to the storage tank 13, the injection pipeline, the main compression circuit and the waste heat pipeline by electrical signals. The control cabinet 42 detects the relevant data in the storage tank 13, the injection pipeline, the main compression circuit and the waste heat pipeline and controls the flow in the injection pipeline, the main compression circuit and the waste heat pipeline to quickly and efficiently adjust the flow of the circulating working medium.

[0108] In the implementation of the present invention, a heat pump refrigerator 201 is provided outside the storage tank 13. The change of the internal temperature of the storage tank 13 can be controlled by the heat pump refrigerator 201. When the heat pump refrigerator 201 is used for heating, the temperature of the storage tank 13 increases, and when the heat pump refrigerator 201 is used for cooling, the temperature of the storage tank 13 decreases.

[0109] In the implementation of the present invention, the injection pipeline includes a first pipeline 101, the input port of the first pipeline 101 is connected to the CO2 tanker 1, and the output port of the first pipeline 101 is connected to the input port of the storage tank 13; the first valve 2, the primary pump 7, the fourth valve 8, the flow meter 4, the third valve 5 and the gasifier 6 are arranged in sequence from the input port to the output port of the first pipeline 101; the flow meter 4 is connected to the control cabinet 42 by electrical signals. By arranging the gasifier 6 and the primary pump 7 on the first pipeline 101, CO2 can be compressed and gasified and input into the storage tank 13. A first branch 301 is arranged on the first pipeline 101, the input port of the first branch 301 is connected between the first valve 2 and the primary pump 7, and the output port of the first branch 301 is connected between the fourth valve 8 and the flow meter 4; a second valve 3 is arranged on the first branch 301. By arranging the first branch 301, CO2 can be directly input into the storage tank 13 after being gasified.

[0110] In the above embodiment, another optional implementation is that a second branch 302 is provided on the first pipeline 101, the input port of the second branch 302 is connected between the primary pump 7 and the fourth valve 8, the output port of the second branch 302 is connected between the fourth valve 8 and the flow meter 4, and a fifth valve 9 and a secondary pump 10 are sequentially provided on the second branch 302 from the input port to the output port. By providing the second branch 302, CO2 can be gasified and enter the input storage tank 13 after being double compressed by the primary pump 7 and the secondary pump 10.

[0111] Preferably, a third branch 303 is provided on the first pipeline 101, the input port of the third branch 303 is connected between the flow meter 4 and the third valve 5, the output port of the third branch 303 is connected between the gasifier 6 and the seventh valve 12, and a sixth valve 11 is provided on the third branch 303. By providing the third branch 303, CO2 can be directly input into the storage tank 13 without being gasified, and in combination with the first pipeline 101, the first branch 301 and the second branch 302, CO2 can be input into the storage tank 13 in gaseous or liquid form in multiple ways.

[0112] Specifically, the injection pipeline is used to ensure that the total amount of working fluid is filled. The specific filling process is as follows: the CO2 injection pipeline is mainly used for the CO2 filling process. During the CO2 filling process, after the system is vacuumed, the CO2 in the CO2 tanker 1 is injected into the system. The liquid CO2 flowing out of the CO2 tanker 1 flows into the flowmeter 4 through the first valve 2 of the first pipeline 101 and the second valve 3 of the first branch 301 to measure its flow, and then enters the gasifier 6 through the third valve 5 to complete gasification. The gasified CO2 is injected into the storage tank 13 through the seventh valve 12 of the first pipeline 101. With the continuous injection of gaseous CO2, the pressure in the system continues to increase. When the pressure reaches the pressure of the CO2 tanker 1, the primary pump 7 is started, and the liquid CO2 flowing out of the CO2 tanker 1 flows into the primary pump 7 through the first valve 2 for pressure boosting. The pressurized CO2 flows into the flowmeter 4 through the fourth valve 8 to measure its flow, and then enters the gasifier 6 through the third valve 5 to complete gasification. The gasified CO2 is injected into the storage tank 13 through the seventh valve 12. Since the volume of the storage tank 13 is fixed, the temperature in the system will continue to rise for constant volume filling. After reaching the set pressure, it is changed to direct liquid injection. During the liquid injection process, the liquid CO2 flowing out of the CO2 tanker 1 flows into the primary pump 7 through the first valve 2 for pressure boosting. The pressurized CO2 passes through the fourth valve 8 and the flow meter 4 in turn, and is directly injected into the storage tank 13 through the sixth valve 11 and the seventh valve 12. Due to the high temperature, the liquid CO2 injected into the storage tank 13 at the beginning will gradually gasify and disappear. When there is enough liquid CO2, there will be liquid CO2 remaining in the storage tank 13. Observe the liquid level of the storage tank 13. When it exceeds the specified value, it is modified to inject gaseous CO2. During the gas injection process, the liquid CO2 flowing out of the CO2 tanker 1 flows through the first valve 2, the primary pump 7, the fourth valve 8, the flow meter 4, the third valve 5, the gasifier 6 and the seventh valve 12 in turn and is finally injected into the storage tank 13. When the pressure in the system is high, the secondary pump 10 can be turned on, that is, the liquid CO2 flowing out of the CO2 tanker 1 flows through the first valve 2, the primary pump 7, the fifth valve 9 and the secondary pump 10 in sequence to complete two pressure increases, and then flows into the flow meter 4 to measure its flow, and then decides whether to flow through the third valve 5 and the gasifier 6 to inject gas into the system, or to flow through the sixth valve 11 to inject liquid into the system according to needs. During the filling process, the temperature and pressure of each point in the system are detected while filling, and the liquid level of the storage tank 13 is observed to decide whether to fill liquid or gas, until the CO2 injected into the system reaches the total amount of working fluid required by the system.In the implementation of the present invention, the main compression circuit includes a separator 15, the working fluid injection port of the separator 15 is connected to the output port end of the storage tank 13; the input port of the third pipeline 103 is connected to the output port of the separator 15, and the first compressor 16, the first regulating valve 32, the high-pressure turbine 33 and the first check valve 23 are sequentially arranged from the input port to the output port of the third pipeline 103, and the input port of the tenth valve 24 is connected to the output port end of the third pipeline 103; the high-pressure turbine 33 is the first turbine of the expansion process in the gas turbine having multiple turbines; in the third The first pipeline of the first reheater 18, the first pipeline of the second reheater 19, and the first pipeline of the first heater 20 are connected in sequence between the first compressor 16 and the first regulating valve 32 of the pipeline 103, and the first pipeline of the first reheater 18 is located near the outlet of the first compressor 16; the first pipeline of the first reheater 18 and the first pipeline of the second reheater 19 are working fluid heating pipelines, that is, the working fluid is heated through these pipelines, and the second pipeline of the first reheater 18 and the second pipeline of the second reheater 19 are working fluid heat release pipelines, that is, the working fluid releases heat through these pipelines;.

[0113] The first compressor 16 is used to compress and transport CO2; the first regenerator 18 is a low-temperature regenerator, and the second regenerator 19 is a high-temperature regenerator; the first regenerator 18 and the second regenerator 19 are used to recover the heat of CO2 in the fourth pipeline 104 and heat the CO2 in the third pipeline 103; the first regulating valve 32 is used to adjust the flow of CO2 and is electrically connected to the control cabinet 42; CO2 flows through the high-pressure turbine 33 to expand and do work, and a temperature and pressure sensor is provided at the input port of the high-pressure turbine 33, and the temperature and pressure sensors are electrically connected to the control cabinet 42 respectively; the first check valve 23 prevents the initial CO2 from O2 does not reach the specified pressure and flows back to the high-pressure turbine 33; the input port of the fourth pipeline 104 is connected to the output port of the tenth valve 24, and the output port of the fourth pipeline 104 is connected to the heat dissipation pipelines of the second regenerator 19 and the first regenerator 18 in sequence; the first regenerator 18 and the second regenerator 19 are used to recover the heat of CO2 in the fourth pipeline 104; the input port of the second pipeline 102 is connected to the output port of the fourth pipeline 104, and the output port of the second pipeline 102 is connected to the circulation inlet of the separator 15; the twentieth valve 49 and the cooler 50 are sequentially arranged from the input port to the output port of the second pipeline 102. The cooler 50 is used to cool CO2.

[0114] In the above embodiment, another optional implementation is that the main compression circuit also includes a fourth branch 304, the fourth branch 304 input port is connected between the first regulating valve 32 and the first heater 20, and the fourth branch 304 output port is connected between the first check valve 23 and the tenth valve 24; the fourth branch 304 is sequentially provided with a ninth valve 21 and a first throttle valve 22 from the input port to the output port.

[0115] The working process of the main compression circuit is as follows: at the beginning, during the startup process, the cooler 50 is first opened to allow the cooling water to circulate, and then the first compressor 16 is started. The CO2 in the storage tank 13 enters the first compressor 16 for compression after passing through the eighth valve 14 and the separator 15, and the first anti-surge valve 17 is opened. The compressed CO2 passes through the first regenerator 18, the second regenerator 19 and the first heater 20 of the third pipeline 103 in sequence. At the same time, the ninth valve 21 is not opened to hold the pressure. After the pressure gradually reaches the design pressure, the ninth valve 21 is opened, and the CO2 enters the first throttle valve 22 for throttling through the ninth valve 21. At the same time, the fifteenth valve 39 is opened so that the waste heat can be used to heat the CO2 in the first heater 20.

[0116] Preferably, the main compression circuit further includes a first anti-surge branch 401, the input port of the first anti-surge branch 401 is connected between the first compressor 16 and the first regenerator 18, the output port of the first anti-surge branch 401 is connected to the third inlet of the separator 15, and a first anti-surge valve 17 is arranged on the first anti-surge branch 401. The first anti-surge valve 17 is used to prevent the third pipeline 103 from surging.

[0117] In the implementation of the present invention, the waste heat pipeline includes a first waste heat pipeline 501, the output end of the first waste heat pipeline 501 is connected to the second pipeline inlet of the first heater 20; a fifteenth valve 39 is arranged on the first waste heat pipeline 501; the input port of the second waste heat pipeline 502 is connected to the second pipeline outlet of the first heater 20, and the output port of the second waste heat pipeline 502 is connected to the outside. The waste heat heats the CO2 in the third pipeline 103 through the first heater 20.

[0118] During the startup of the system, the cooler 50 is first opened to allow the cooling water to circulate, and then the first compressor 16 is started. The CO2 in the storage tank 13 enters the first compressor 16 for compression after passing through the eighth valve 14 and the separator 15, and the first anti-surge valve 17 is opened. The compressed CO2 passes through the first reheater 18, the second reheater 19 and the first heater 20 of the third pipeline 103 in sequence. At the same time, the ninth valve 21 is not opened to hold the pressure. After the pressure gradually reaches the design pressure, the ninth valve 21 is opened, and the CO2 enters the first throttle valve 22 for throttling through the ninth valve 21. At the same time, the fifteenth valve 39 is opened so that the waste heat can be used to heat the CO2 in the first heater 20. At the same time, the second compressor 27 is started, and the throttled CO2 passes through the tenth valve 24 in sequence through the second reheater 19 and the first reheater 18 to release heat. The CO2 after heat release is divided into two branches, one of which enters the cooler 50 through the twentieth valve 49 for cooling, and then enters the separator 15 for gas-liquid separation. The other path enters the second compressor 27 through the eleventh valve 26 of the fifth pipeline 105 for recompression, and the second anti-surge valve 28 is opened. The recompressed CO2 flows through the second heater 29, while the twelfth valve 30 and the thirteenth valve 34 are not opened to hold the pressure. When the pressure reaches the design pressure, the twelfth valve 30 is opened, the second throttle valve 31 of the second compression circuit is started, and the seventeenth valve 41 is opened at the same time, so that the residual heat can enter the second heater 29 to heat the CO2 flowing therethrough. The CO2 heated in the second heater 29 enters the second throttle valve 31 through the twelfth valve 30 for throttling, and then mixes with the CO2 at the output port of the second regenerator 19 through the second check valve 25, and then flows into the first regenerator 18 for heat release. The first check valve 23 and the second check valve 25 in the cycle can prevent CO2 from flowing into the high-pressure turbine 33 or the low-pressure turbine 36 before the rush condition is met. At this time, the first regulating valve 32 and the second regulating valve 35 are both in the closed state. The pressure and temperature of CO2 at the inlet of the high-pressure turbine 33 and the low-pressure turbine 36 are continuously observed. When the conditions for the start-up are met, the first throttle valve 22 and the second throttle valve 31 are closed, and the first regulating valve 32 and the second regulating valve 35 are opened to gradually adjust the system to the design operating point. At this time, the CO2 at the outlet of the first heater 20 enters the high-pressure turbine 33 through the first regulating valve 32 to expand and do work, and then enters the second regenerator 19 through the first check valve 23 and the tenth valve 24 to release heat. The CO2 at the outlet of the second heater 29 enters the low-pressure turbine 36 through the thirteenth valve 34 and the second regulating valve 35 to expand and do work, and then mixes with the CO2 at the outlet of the second regenerator 19 through the second check valve 25, and then flows into the first regenerator 18 to release heat. The safety valve 37 can ensure the safe operation of the system under high pressure. When the system pressure is too high, the pressure can be released through the safety valve 37.In addition, before the fifteenth valve 39 is opened, the residual heat flows directly into the outside through the fourteenth valve 38 for user use. After the fifteenth valve 39 is opened, the fourteenth valve 38 can be closed as needed. Before the seventeenth valve 41 is opened, the residual heat after passing through the first heater 20 flows into the outside through the sixteenth valve 40 for user use. After the seventeenth valve 41 is opened, the sixteenth valve 40 can be closed as needed, and the residual heat after passing through the second heater 29 flows into the outside.

[0119] In the implementation of the present invention, the system also includes a second compression circuit, which includes a fifth pipeline 105, the input port of the fifth pipeline 105 is connected to the output port end of the fourth pipeline 104, and the input port of the fifth pipeline 105 is connected to the input port of the twentieth valve 49, and the output port of the fifth pipeline 105 is connected to the output port end of the second reheater 19. The fifth pipeline 105 is sequentially provided with an eleventh valve 26, a second compressor 27, a thirteenth valve 34, a second regulating valve 35, a low-pressure turbine 36 and a second check valve 25 from the input port to the output port, and the outlet of the second check valve 25 is connected between the second pipeline of the first reheater 18 and the second pipeline of the second reheater 19; the second pipeline of the second heater 29 is connected between the second compressor 27 and the thirteenth valve 34 of the fifth pipeline 105; the second heater 29 is a low-temperature heater, and the low-pressure turbine 36 is the last turbine in the expansion process in some gas turbines with multiple turbines.

[0120] The second compression circuit is used to compress the working fluid again to do work, and at the same time, the waste heat pipeline is used for reheating, which improves the utilization efficiency of the waste heat. The eleventh valve 26 is used to open and close the second compression circuit, and the second heater 29 is used to reheat CO2 using waste heat; the second regulating valve 35 is used to adjust the flow of CO2 flowing into the low-pressure turbine 36, and is connected to the control cabinet 42 by electrical signals; the low-pressure turbine 36 is used for CO2 expansion to do work, and a temperature and pressure sensor is provided at the input port of the low-pressure turbine 36, and the temperature and pressure sensors are respectively connected to the control cabinet 42 by electrical signals; the second check valve 25 prevents CO2 from flowing back into the low-pressure turbine 36 when it does not reach the specified pressure at the beginning;

[0121] The main compression loop of the S-CO2 power cycle and the second compression loop of the S-CO2 power cycle are connected by the eleventh valve 26. When the eleventh valve 26 is opened, CO2 flows through the second compression loop of the S-CO2 power cycle, and when the eleventh valve 26 is closed, CO2 does not flow through the second compression loop of the S-CO2 power cycle. In addition, for different operation processes of the system, the flow trajectory of CO2 in the S-CO2 power cycle is different.

[0122] In the implementation of the present invention, the second compression circuit includes a fifth branch 305, the input port of the fifth branch 305 is connected between the thirteenth valve 34 and the first pipeline of the second heater 29, and the output port is connected between the second check valve 25 and the low-pressure turbine 36. The twelfth valve 30 and the second throttle valve 31 are arranged in sequence from the input port to the output port of the fifth branch 305.

[0123] The working principle of the second compression circuit is to start the second compressor 27, and CO2 enters the second compressor 27 for compression after passing through the eleventh valve 26, and the second anti-surge valve 28 is opened. The compressed CO2 passes through the second heater 29 in sequence, and the twelfth valve 30 is not opened to hold the pressure. After the pressure gradually reaches the design pressure, the twelfth valve 30 is opened, and CO2 enters the second throttle valve 31 for throttling through the twelfth valve 30, and the seventeenth valve 41 is opened at the same time, so that the waste heat can be used to heat the CO2 in the second heater 29, and the medium pipeline of the second heater 29 is connected to the fifth pipeline 105, and the waste heat pipeline of the second heater 29 is connected to the second waste heat pipeline 502.

[0124] In the above embodiment, another optional implementation is that the second compression circuit includes a second anti-surge branch 402, the input port of the second anti-surge branch 402 is connected between the second pipe of the second compressor 27 and the second heater 29, the output port of the second anti-surge branch 402 is connected between the second compressor 27 and the eleventh valve 26, and a second anti-surge valve 28 is arranged on the second anti-surge branch 402. The second anti-surge valve 28 is used to prevent the fifth pipeline 105 from surging. Start the second compressor 27, and the throttled CO2 flows through the second regenerator 19 and the first regenerator 18 in sequence through the tenth valve 24 to release heat. The CO2 after heat release is divided into two branches, one of which enters the cooler 50 through the twentieth valve 49 for cooling, and then enters the separator 15 for gas-liquid separation.

[0125] like Figure 6 As shown, Figure 6 This is the system structure diagram of the maintenance process. Figure 6 The system includes a CO2 discharge module, which includes a first discharge pipe 601, wherein the input port end of the first discharge pipe 601 is connected to the storage tank 13, the output port end of the first discharge pipe 601 is connected to the CO2 dewar tank 45, and an eighteenth valve 44 is arranged on the first discharge pipe 601; the input port end of the second discharge pipe 602 is connected to the input port end of the eighteenth valve 44, the output port end of the second discharge pipe 602 is connected to the CO2 dewar tank 45, and a nineteenth valve 47 and a CO2 booster 48 are arranged in sequence on the second discharge pipe 602; and a refrigerator 46 is connected to the CO2 dewar tank 45.

[0126] When the system is overhauled and CO2 is discharged, the storage tank 13 is cooled and the liquid CO2 is discharged to the outside; the storage tank 13 is heated and the gaseous CO2 is discharged to the dewar tank 45, and the CO2 booster 48 is used to press the gaseous CO2 into the external dewar tank 45, and finally the gaseous CO2 is discharged.

[0127] The CO2 tanker 1 is mainly divided into a CO2 dewar tank 45 and a refrigeration machine 46. The CO2 dewar tank 45 is used to store liquid CO2. The refrigeration machine 46 provides cooling for the CO2 dewar tank 45 to maintain the low temperature state of the CO2 dewar tank 45 and liquefy the gaseous CO2 recovered into the CO2 dewar tank 45 into liquid.

[0128] The CO2 discharge module is mainly used in the system maintenance process. During the system maintenance process, the CO2 needs to be recovered into the CO2 Dewar tank 45 first. During the recovery process, first open the eighth inlet and outlet valve 14 of the storage tank 13 connecting the system, start the heat pump refrigerator 201 to cool the storage tank 13, maintain the temperature of the storage tank 13 at about 5°C, so that the supercritical CO2 forms a liquid in the storage tank 13, and the system pressure drops at the same time. Afterwards, the liquid CO2 in the storage tank 13 is discharged into the CO2 dewar tank 45 through the eighteenth valve 44 by using the pressure difference. When the liquid is almost discharged, in order to discharge the gaseous CO2 as much as possible, the heat pump refrigerator 201 can be started to heat the storage tank 13 appropriately to increase the system pressure, so as to recover the gaseous CO2 into the CO2 dewar tank 45 through the eighteenth valve 44 through the pressure difference to the maximum extent. When the pressure in the storage tank 13 is lower than the pressure in the CO2 dewar tank 45, the gaseous CO2 in the storage tank 13 enters the CO2 booster 48 through the nineteenth valve 47 for boosting, and then further discharges the CO2 into the CO2 dewar tank 45 by using the pressure difference. Afterwards, the CO2 in the storage tank 13 is emptied through the gas discharge valve 43. During the whole process of recovering CO2 into the CO2 dewar tank 45, the refrigerator 46 is always in the open state.

[0129] During the system filling, startup, operation, shutdown and maintenance process, the control cabinet 42 continuously monitors the temperature and pressure conditions at various locations in the system.

[0130] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for operating a waste heat driven S-CO2 power cycle system, characterized in that: The steps include: CO2 filling, filling the storage tank (13) with system working fluid through the injection pipeline; The system is started, the main compression circuit and the waste heat pipeline are opened, the working medium in the storage tank (13) is controlled to reach a preset temperature and the working medium in the main compression circuit is controlled to reach a preset pressure; the first throttle valve (22) is opened, and after the working medium reaches a preset pressure, the high-pressure turbine (33) is turned on; During variable operating conditions, the load is increased, the fifteenth valve (39) of the waste heat pipeline is opened wide, the working fluid flow rate is increased, the storage tank (13) is heated to maintain a constant inlet pressure of the first compressor (16); the load is reduced, the fifteenth valve (39) of the waste heat pipeline is opened narrowly, the CO2 flow rate is reduced, the storage tank (13) is cooled to maintain a constant inlet pressure of the first compressor (16); when the ambient temperature is lower than the normal operating temperature, the cooling water flow rate is adjusted, liquid CO2 is formed at the output port of the cooler (50), and is separated into the storage tank (13) through the separator (15), and the heat pump refrigerator (201) heats the CO2 in the storage tank (13).

2. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The CO2 filling is performed by injecting the system working fluid into the storage tank (13) in the form of gas-liquid alternating injection through the injection pipeline.

3. The method for operating a waste heat driven S-CO2 power cycle system according to claim 2, characterized in that: The CO2 filling method includes the following steps: Gaseous CO2 filling is achieved by opening the first valve (2) and the sixth valve (11) and closing the second valve (3), the fifth valve (9) and the third valve (5); After the storage tank (13) reaches a predetermined pressure, the second valve (3) is closed and the fourth valve (8) is opened, so that CO2 is pressurized and continues to be filled through the primary pump (7); After the storage tank (13) reaches the set pressure, liquid CO2 is filled by closing the third valve (5) and opening the sixth valve (11); When the liquid CO2 in the storage tank (13) exceeds a specified value, the gaseous CO2 is filled by closing the sixth valve (11) and opening the third valve (5); When the pressure in the storage tank (13) exceeds a predetermined value, the fourth valve (8) is closed and the fifth valve (9) is opened, so that the primary pump (7) and the secondary pump (10) are simultaneously pressurized to complete CO2 filling.

4. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The system startup includes the following steps: Open the cooler (50) to allow cooling water to circulate. The first compressor (16) is started to allow the CO2 in the storage tank (13) to enter the first compressor (16) for compression after passing through the eighth valve (14) and the separator (15), and the compressed CO2 is heated by passing through the first regenerator (18), the second regenerator (19) and the first heater (20) of the third pipeline (103) in sequence; The ninth valve (21) is closed to hold the pressure, and when the pressure gradually reaches a predetermined pressure, the ninth valve (21) is opened, and CO2 enters the first throttle valve (22) through the ninth valve (21) for throttling; The fifteenth valve (39) is opened to allow the first heater (20) to utilize the waste heat to heat the CO2 and to start the high-pressure turbine (33).

5. The method for operating a waste heat driven S-CO2 power cycle system according to claim 4, characterized in that: The system startup also includes the following steps: After the first compressor (16) is turned on, the first anti-surge valve (17) is also turned on.

6. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The variable operating condition operation and load increase include the following steps: Open the fifteenth valve (39) and the seventeenth valve (41), and simultaneously open the eighth valve (14); Starting the heat pump refrigerator (201) to heat the storage tank (13), allowing CO2 to flow into the main compression circuit, and maintaining the inlet pressure of the first compressor (16) unchanged; When the inlet pressure of the first compressor (16) reaches a preset pressure, the eighth valve (14) is closed to allow the system to operate normally, and at the same time, the heat pump refrigerator (201) is turned off to stop heating.

7. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The variable operating condition operation and load reduction comprises the following steps: The fifteenth valve (39) and the seventeenth valve (41) are closed, and the eighth valve (14) is opened; Starting the heat pump refrigerator (201) to cool the storage tank (13), allowing the CO2 in the main pressure circuit to flow into the storage tank (13), and maintaining the inlet pressure of the first compressor (16) unchanged; After the system runs stably, the eighth valve (14) is closed and the heat pump refrigerator (201) is turned off at the same time to stop refrigeration.

8. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The variable operating condition operation, in which the ambient temperature is lower than the normal operating temperature, comprises the following steps: The cooling water flow rate in the cooler (50) is adjusted so that the CO2 at the inlet of the first compressor (16) is in a gaseous state. When the CO2 at the outlet of the cooler (50) is in liquid state, the gas-liquid separation is performed through the separator (15). Open the eighth valve (14) to store the liquid CO2 into the storage tank (13); The heat pump refrigerator (201) is started to heat the storage tank (13), thereby increasing the inlet temperature of the first compressor (16) and reducing the formation of liquid CO2.

9. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The following steps are also included: The system is shut down, the fifteenth valve (39) and the seventeenth valve (41) of the waste heat pipeline are gradually closed to reduce the waste heat, the frequency and the output pressure of the first compressor (16) are reduced, and the high-pressure turbine (33) is disconnected; the first throttle valve (22) is bypassed, the storage tank (13) is refrigerated to stabilize the inlet pressure of the first compressor (16), the first compressor (16) is stopped, and the cooling water is turned off.

10. The method for operating a waste heat driven S-CO2 power cycle system according to claim 1, characterized in that: The following steps are also included: During system maintenance, CO2 is discharged, and the storage tank (13) is cooled to discharge the liquid CO2 into the CO2 Dewar tank (45); after the liquid CO2 is discharged, the storage tank (13) is heated to discharge the gaseous CO2 into the CO2 Dewar tank (45), and a CO2 booster (48) is used to press the system gaseous CO2 into the CO2 Dewar tank (45) until the gaseous CO2 is emptied.

11. A waste heat driven S-CO2 power cycle system, characterized in that: include: A CO2 tanker (1), an injection pipeline, a storage tank (13), a main compression circuit, a first heater (20), a high-pressure turbine (33), a waste heat pipeline and a separator (15); The input port of the injection pipeline is connected to the CO2 tank truck (1), and the outlet of the injection pipeline is connected to the injection port of the storage tank (13); The first inlet of the separator (15) is connected to the outlet of the storage tank (13); The main compression circuit input port is connected to the first outlet of the separator (15), and the main compression circuit output port is connected to the second inlet of the separator (15); the working fluid at the main compression circuit output port is first heated by the expanded CO2 exhaust gas, and then heated by the waste heat pipeline for a second time, and then the high-temperature CO2 enters the high-pressure turbine (33) to expand and perform work; The main compression circuit comprises a first heater (20) and a high-pressure turbine (33), wherein the first heater (20) is close to the main compression circuit input port; the high-pressure turbine (33) is close to the main compression circuit output port; The waste heat pipeline is in communication with the waste heat flow side of the first heater (20) and is used to transport the waste heat to the first heater (20) to heat the working medium flowing through the first heater (20).

12. The waste heat driven S-CO2 power cycle system according to claim 11, characterized in that: A heat pump refrigerator (201) is arranged outside the storage tank (13), and the heat pump refrigerator (201) is used to control the internal temperature of the storage tank (13).

13. A waste heat driven S-CO2 power cycle system according to claim 11 or 12, characterized in that: The main compression circuit comprises: a third pipeline (103), wherein the input port of the third pipeline (103) is in communication with the output port of the separator (15), and a first compressor (16), a first regulating valve (32), a high-pressure turbine (33) and a first check valve (23) are sequentially arranged from the input port to the output port of the third pipeline (103), and the input port of a tenth valve (24) is connected to the output port end of the third pipeline (103); A first pipeline of a first heat regenerator (18), a first pipeline of a second heat regenerator (19), and a first pipeline of a first heater (20) are connected in sequence at a position between the first compressor (16) and the first regulating valve (32) of the third pipeline (103), and the first heat regenerator (18) is located near the outlet of the first compressor (16); a fourth pipeline (104), wherein the input port of the fourth pipeline (104) is connected to the output port of the tenth valve (24), and the output port of the fourth pipeline (104) is connected in sequence to the heat dissipation pipeline of the second heat regenerator (19) and the heat dissipation pipeline of the first heat regenerator (18); A second pipeline (102), wherein the input port of the second pipeline (102) is connected to the output port of the fourth pipeline (104), and the output port of the second pipeline (102) is connected to the circulation inlet of the separator (15); a twentieth valve (49) and a cooler (50) are sequentially arranged from the input port to the output port of the second pipeline (102).

14. The waste heat driven S-CO2 power cycle system according to claim 11, characterized in that: The waste heat pipeline comprises: A first waste heat pipeline (501), wherein the output port of the first waste heat pipeline (501) is connected to the second pipeline inlet of the first heater (20); a fifteenth valve (39) is provided on the first waste heat pipeline (501); A second waste heat pipe (502), wherein the input port of the second waste heat pipe (502) is connected to the first pipe outlet of the first heater (20), and the output port of the second waste heat pipe (502) is connected to the outside.

15. The waste heat driven S-CO2 power cycle system according to claim 13, characterized in that: The system further comprises a second compression circuit, the second compression circuit comprising: a fifth pipeline (105), wherein the input port of the fifth pipeline (105) is connected to the output port of the fourth pipeline (104), and the input port of the fifth pipeline (105) is connected to the input port of the twentieth valve (49), and the output port of the fifth pipeline (105) is connected to the output port end of the second heat regenerator (19), The fifth pipeline (105) is provided with an eleventh valve (26), a second compressor (27), a thirteenth valve (34), a second regulating valve (35), a low-pressure turbine (36) and a second check valve (25) in sequence from the input port to the output port; the outlet of the second check valve (25) is connected between the second pipeline of the first regenerator (18) and the second pipeline of the second regenerator (19); A second pipeline of a second heater (29) is connected between the second compressor (27) of the fifth pipeline (105) and the thirteenth valve (34); The first pipe of the second heater (29) is in communication with the fifth pipe (105), and the second pipe of the second heater (29) is in communication with the second waste heat pipe (502).

16. The waste heat driven S-CO2 power cycle system according to claim 11, characterized in that: The system also includes a CO2 discharge module, and the CO2 discharge module includes: a first discharge pipe (601), wherein an input end of the first discharge pipe (601) is in communication with the storage tank (13), and an output end of the first discharge pipe (601) is in communication with a CO2 Dewar tank (45), and an eighteenth valve (44) is provided on the first discharge pipe (601); a second discharge pipe (602), wherein the input port of the second discharge pipe (602) is connected to the input port of the eighteenth valve (44), the output port of the second discharge pipe (602) is connected to the CO2 Dewar tank (45), and the nineteenth valve (47) and the CO2 booster (48) are sequentially arranged on the second discharge pipe (602); The CO2 Dewar tank (45) is connected to a refrigerator (46).

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