A regenerative supercritical carbon dioxide Brayton cycle system

Abstract

The application discloses a supplemental combustion type supercritical carbon dioxide Brayton cycle system, which comprises a supercritical carbon dioxide closed-type Brayton cycle subsystem; a supercritical carbon dioxide outlet of a partition type heater in the supercritical carbon dioxide closed-type Brayton cycle subsystem is connected with a supercritical carbon dioxide inlet of a combustion chamber; a combustion product outlet of the combustion chamber is connected with a supercritical carbon dioxide inlet of a turbine expander; a working medium outlet of a compressor in the supercritical carbon dioxide closed-type Brayton cycle subsystem is connected with a working medium outlet of a second cooler; the working medium outlet of the second cooler is connected with an inlet of a supercritical carbon dioxide storage tank; and an outlet of the supercritical carbon dioxide storage tank is connected with a connecting pipeline between an outlet of a water separation tank and an inlet of the compressor. The application can realize the sudden increase of the instantaneous power of the system through the rapid combustion and heat release of oxygen and hydrocarbon fuel in the combustion chamber, and can also be used as a standby emergency heat source.

Description

Technical Field

[0001] This invention relates to the field of thermal cycle system technology, and in particular to a supplementary combustion supercritical carbon dioxide Brayton cycle system. Background Technology

[0002] Supercritical carbon dioxide (CO2) Brayton cycle systems have attracted widespread attention due to their high power density, simple and compact structure, high efficiency, and safe and pollution-free working fluid. Currently, extensive research and applications have been conducted in various fields such as solar energy, nuclear energy, distributed energy, marine propulsion, and fuel cells, and it is considered one of the most promising energy conversion systems.

[0003] In actual operation, supercritical carbon dioxide (CO2) Brayton cycle systems may face the demand for a rapid increase in load, especially the system as a power unit. How to meet the demand for a rapid increase in load and achieve load regulation of the system in the later stage is a key problem that urgently needs to be solved.

[0004] For supercritical carbon dioxide (CO2) Brayton cycle systems, although there are many current load regulation methods, mostly involving adjusting valve openings and expander speeds using controllers, these methods still cannot meet the requirements for instantaneous power boost. This is mainly because traditional supercritical carbon dioxide (CO2) Brayton cycle systems employ a closed-loop circulation method with indirect heating. Due to the significant thermal inertia of the indirect heaters, the rate of change of the system's output power cannot be further increased.

[0005] Therefore, there is an urgent need to develop a technology to solve the above-mentioned technical problems. Summary of the Invention

[0006] The purpose of this invention is to address the technical deficiencies of existing technologies by providing a supplementary combustion supercritical carbon dioxide Brayton cycle system.

[0007] Therefore, the present invention provides a supplementary combustion supercritical carbon dioxide Brayton cycle system, including a supercritical carbon dioxide closed Brayton cycle subsystem, a combustion chamber, a second cooler, and a supercritical carbon dioxide storage tank.

[0008] The supercritical carbon dioxide closed Brayton cycle subsystem includes, in sequence, a wall-mounted heater, a turbine expander, a first cooler, a water separator, a compressor, and a water discharge valve;

[0009] The supercritical carbon dioxide outlet of the indirect-fired heater in the supercritical carbon dioxide closed Brayton cycle subsystem is connected to the supercritical carbon dioxide inlet of the combustion chamber to supply supercritical carbon dioxide to the combustion chamber.

[0010] The fuel inlet of the combustion chamber is used to introduce fuel;

[0011] The combustion product outlet of the combustion chamber is connected to the supercritical carbon dioxide inlet of the turbine expander;

[0012] The working fluid outlet of the compressor in the supercritical carbon dioxide closed Brayton cycle subsystem is connected to the working fluid outlet of the second cooler, and is used to output compressed supercritical carbon dioxide to the second cooler.

[0013] The working fluid outlet of the second cooler is connected to the inlet of the supercritical carbon dioxide storage tank.

[0014] The outlet of the supercritical carbon dioxide storage tank is connected to the outlet of the water separator and the inlet of the compressor via a connecting pipe.

[0015] As can be seen from the technical solution provided by the present invention above, compared with the prior art, the present invention provides a supplementary combustion supercritical carbon dioxide Brayton cycle system, which is scientifically designed and achieves a sudden increase in instantaneous power of the system by rapidly burning oxygen and hydrocarbon fuels in the combustion chamber to release heat.

[0016] Furthermore, the system of the present invention can also be used as a backup emergency heat source when the heat source of the Brayton system fails, which has significant practical implications. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a supplementary combustion supercritical carbon dioxide Brayton cycle system provided by the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this patent, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "setting" should be interpreted broadly. For example, they can refer to direct connection or indirect connection; they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this patent according to the specific circumstances.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] See Figure 1 The present invention provides a supercritical carbon dioxide Brayton cycle system with afterburning, including a supercritical carbon dioxide closed Brayton cycle subsystem, a combustion chamber 2-1, a second cooler 3 and a supercritical carbon dioxide storage tank 4.

[0022] The supercritical carbon dioxide closed Brayton cycle subsystem includes, in sequence, a partitioned heater 1-1, a turbine expander 1-2, a first cooler 1-3, a water separator 1-4, a compressor 1-5, and a water discharge valve 1-6;

[0023] The supercritical carbon dioxide outlet of the indirect-contact heater 1-1 in the supercritical carbon dioxide closed Brayton cycle subsystem is connected to the supercritical carbon dioxide inlet of the combustion chamber 2, and is used to supply supercritical carbon dioxide to the combustion chamber 2.

[0024] The fuel inlet of combustion chamber 2-1 is used to introduce fuel 2-4;

[0025] The combustion product outlet of combustion chamber 2-1 is connected to the supercritical carbon dioxide inlet of turbine expander 1-2;

[0026] The working fluid outlet of compressor 1-5 in the supercritical carbon dioxide closed Brayton cycle subsystem is connected to the working fluid outlet of the second cooler 3, and is used to output compressed supercritical carbon dioxide (CO2) to the second cooler 3.

[0027] The working fluid outlet of the second cooler 3 is connected to the inlet of the supercritical carbon dioxide storage tank 4.

[0028] The outlet of the supercritical carbon dioxide storage tank 4 is connected to the outlet of the water separator 1-4 and the inlet of the compressor 1-5 via a connecting pipe.

[0029] It should be noted that supercritical carbon dioxide is a carbon dioxide fluid maintained above the critical temperature and critical pressure (supercritical fluid).

[0030] It should be noted that, in specific implementation, the supercritical carbon dioxide closed Brayton cycle system can be a basic cycle consisting of a sequentially connected indirect-contact heater 1-1, a turbine expander 1-2, a first cooler 1-3, and a compressor 1-5, or it can be other complex cycle configurations, such as regenerative, regenerative-recompression, etc. This invention is applicable to all types of supercritical carbon dioxide (CO2) Brayton cycle configurations.

[0031] In this invention, specifically, for the supercritical carbon dioxide closed Brayton cycle subsystem, the working fluid outlet of compressor 1-5 is connected to the supercritical carbon dioxide inlet of indirect-contact heater 1-1.

[0032] The supercritical carbon dioxide outlet of the indirect-contact heater 1-1 is connected to the supercritical carbon dioxide inlet of the turbine expander 1-2.

[0033] The supercritical carbon dioxide outlet of the turbine expander 1-2 is connected to the supercritical carbon dioxide inlet of the first cooler 1-3.

[0034] The supercritical carbon dioxide outlet of the first cooler 1-3 is connected to the working fluid inlet of the water separator 1-4.

[0035] The working fluid outlet of water separator 1-4 is connected to the working fluid inlet of compressor 1-5;

[0036] The drain outlet at the bottom of the water separator 1-4 is connected to one end of the water discharge valve 1-6;

[0037] The other end of water drain valves 1-6 is connected to the outside.

[0038] It should be noted that the bottom of the water separator 1-4 is connected to the water discharge valve 1-6 via a pipe. The water discharge valve 1-6 is used to discharge the condensate that settles at the bottom of the water separator 1-4.

[0039] It should be noted that, see Figure 1 As shown, in Figure 1In the supercritical carbon dioxide closed Brayton cycle subsystem shown, supercritical carbon dioxide (CO2) is pressurized to a high-pressure state by compressor 1-5; the working fluid outlet of compressor 1-5 is connected to the supercritical carbon dioxide inlet of indirect heater 1-1, where the supercritical carbon dioxide is heated to a high temperature; the supercritical carbon dioxide outlet of indirect heater 1-1 is connected to the inlet of turbine expander 1-2, where the supercritical carbon dioxide expands and does work; the outlet of turbine expander 1-2 is connected to the supercritical CO2 inlet of cooler 1-3, where the expanded supercritical CO2, with its lower pressure, is cooled to a low temperature; the supercritical CO2 outlet of cooler 1-3 is connected to the working fluid inlet of water separator 1-4, and the working fluid outlet of water separator 1-4 is connected to the inlet of compressor 1-5, where the supercritical CO2 is pressurized by compressor 1-5 to start the next cycle.

[0040] In practice, the cold end inlet of coolers 1-3 is connected to the outlet of an external cold source generating device, which provides the cooling medium and cooling capacity.

[0041] The cold end outlet of coolers 1-3 is connected to the inlet of an external cold source generating device.

[0042] It should be noted that the cold end inlet of cooler 1-3 is connected to the cold end outlet through the inner cavity of the shell of cooler 1-3; that is, the cold end inlet and the cold end outlet are located at both ends of the inner cavity of the shell of cooler 1-3.

[0043] It should be noted that the supercritical carbon dioxide inlet of cooler 1-3 is connected to the supercritical carbon dioxide outlet of cooler 1-3 through a connecting pipe located in the inner cavity of cooler 1-3 shell; therefore, the cold source (such as dry air or cooling water) entering through the cold end inlet of cooler 1-3 can cool the working fluid (specifically the low-pressure working fluid output from turbine expander 1-2) entering through the working fluid inlet of cooler 1-3, thereby cooling it into a low-pressure, low-temperature working fluid.

[0044] In practice, the hot end inlet of the indirect heat heater 1-1 is connected to the heat source outlet of the external heat source system.

[0045] The hot end outlet of the indirect heat exchanger 1-1 is connected to the external atmospheric environment (i.e., the external location) or external equipment, that is, it is connected to the outside world. It should be noted that different heat source outlets are different; they may be discharged into the atmosphere or return to the external heat source system (i.e., the heat source generator).

[0046] In practice, the external heat source system includes one or more of the following: boiler, nuclear energy, waste heat exchanger or solar heat source. For example, hot water can be output from a boiler or solar heat source to the hot end inlet of the indirect heating element 1-1.

[0047] It should be noted that in this invention, the external heat source system can heat the working fluid in the indirect heater 1-1. The high-pressure working fluid delivered by the compressor 1-5 absorbs heat in the indirect heater 1-1 and becomes a high-temperature and high-pressure working fluid. Then, the high-temperature and high-pressure working fluid discharged from the indirect heater 1-1 enters the turbine expander 1-2 and is converted into kinetic energy. In the turbine expander 1-2, when the high-temperature and high-pressure working fluid flows through the rotor, the fluid impacts the blades and drives the rotor to rotate, thereby driving the turbine shaft to rotate. The turbine shaft directly or indirectly drives other loads through the transmission mechanism, outputting mechanical work and converting the energy of the fluid into mechanical energy, causing the working fluid to expand into a low-pressure working fluid.

[0048] The low-pressure working fluid output after expansion and work done by the turbine expander 1-2 is then cooled by the cooler 1-3 to release heat and become a low-pressure, low-temperature working fluid. Then, the low-temperature, low-pressure working fluid is pressurized by the compressor 1-5 to become a low-temperature, high-pressure working fluid, and then returns to the indirect heating element 1-1, where it absorbs heat again to become a high-temperature, high-pressure working fluid, completing the cycle.

[0049] In practical implementation, the load can be, for example, a power grid peak-shaving unit, a ship's power plant, or other existing equipment requiring power supply. The connection method between the load and the turbine expander 1-2 can directly adopt existing and well-known technologies, which will not be elaborated here.

[0050] In this invention, specifically, a supply valve 4-1 is provided on the connecting pipe between the outlet of the supercritical carbon dioxide storage tank 4 and the inlet of the compressor 1-5.

[0051] A filling valve 4-2 is installed on the connecting pipe between the working fluid outlet of the second cooler 3 and the inlet of the supercritical carbon dioxide storage tank 4.

[0052] In this invention, specifically, the combustion chamber 2-1 is connected to the supercritical carbon dioxide closed Brayton cycle subsystem via a first three-way valve 2-2 and a second three-way valve 2-3; the specific connection structure is as follows:

[0053] The inlet of the first three-way valve 2-2 is connected to the supercritical carbon dioxide outlet of the indirect-contact heater 1-1;

[0054] The first outlet of the first three-way valve 2-2 is connected to the supercritical carbon dioxide inlet of the combustion chamber 2-1;

[0055] The second outlet of the first three-way valve 2-2 is connected to the first inlet of the second three-way valve 2-3;

[0056] The second inlet of the second three-way valve 2-3 is connected to the combustion product outlet of the combustion chamber 2-1;

[0057] The outlet of the second three-way valve 2-3 is connected to the supercritical carbon dioxide inlet of the turbine expander 1-2.

[0058] Specifically, the fuel 2-4 introduced into combustion chamber 2-1 is preferably a mixture of oxygen and hydrocarbon fuel. The hydrocarbon fuel can be, for example, methane, ethane, propane, butane, or other hydrocarbon compounds. The hydrocarbon fuel is preferably a hydrocarbon fuel after impurities have been removed. The oxygen is preferably pure oxygen.

[0059] In this invention, specifically, for the supplementary combustion supercritical carbon dioxide Brayton cycle system provided by this invention, when it is necessary to rapidly increase the system output power, pure oxygen and impurity-removed hydrocarbon fuel are introduced into the combustion chamber 2-1, and they are rapidly combusted and released heat in the supercritical carbon dioxide fluid flowing through the combustion chamber 2-1, so that the temperature of the supercritical carbon dioxide at the inlet of the turbine expander 1-2 is rapidly increased (for example, increased to a specified temperature range), thereby instantaneously increasing the system output power;

[0060] It should be noted that most of the water vapor in the combustion products of combustion chamber 2-1 is condensed into liquid in the first cooler 1-3, and then enters the water separator 1-4 together with carbon dioxide. In the water separator 1-4, the condensate settles at the bottom of the tank and is discharged from the system through the pipe connected to the water discharge valve 1-6. The high-purity carbon dioxide flows to the compressor 1-5 through the pipe at the top of the water separator 1-4.

[0061] In addition, when the system is in a steady state and does not require a rapid increase in output power, the indirect heating element 1-1 operates independently, while the combustion chamber 2-1 does not operate.

[0062] In this invention, specifically, the discharge port on the supercritical carbon dioxide storage tank 4 is connected to one end of the discharge valve 4-3;

[0063] The other end of the discharge valve 4-3 is connected to the external atmospheric environment (i.e., the external location) or a pre-set external device, that is, connected to the outside world.

[0064] It should be noted that, in this invention, for the supercritical carbon dioxide closed-loop Brayton cycle subsystem, the working fluid outlet of compressor 1-5 is connected in parallel to a branch, specifically: sequentially connected to the second cooler 3 and the supercritical carbon dioxide storage tank 4; the outlet of the supercritical carbon dioxide storage tank 4 is connected between the outlet of the water separator 1-4 and the inlet of compressor 1-5. The supercritical carbon dioxide storage tank 4 is equipped with a discharge valve 4-3 for releasing supercritical carbon dioxide to the outside. After being cooled by the second cooler 3, the compressed high-pressure carbon dioxide working fluid becomes a low-temperature, high-density working fluid, which is then stored in the supercritical carbon dioxide storage tank 4.

[0065] In this invention, specifically, the supercritical carbon dioxide storage tank 4 is used to replenish the system with supercritical carbon dioxide when the system is deficient in supercritical carbon dioxide.

[0066] It should be noted that when there is a shortage of supercritical carbon dioxide in the system, the supercritical carbon dioxide in the supercritical carbon dioxide storage tank 4 can be used to replenish the system; when there is an excess of working fluid in the supercritical carbon dioxide storage tank 4, the supercritical carbon dioxide can also be transferred to other places through the discharge valve.

[0067] To better understand the technical solution of the present invention, the working mode of the present invention is described below. The system of the present invention specifically includes the following working modes:

[0068] 1. During the normal operation of the supercritical carbon dioxide closed Brayton cycle subsystem, if the system load demand of the supplementary combustion supercritical carbon dioxide Brayton cycle system increases rapidly, pure oxygen and purified hydrocarbon fuel are introduced into the combustion chamber 2-1. The fuel is rapidly combusted and releases heat in the supercritical carbon dioxide fluid flowing through the combustion chamber 2-1, which causes the temperature of the supercritical carbon dioxide at the inlet of the turbine expander 1-2 to increase rapidly, thereby instantly increasing the system output power. At the same time, the speed of the compressor 1-5 is also increased to increase the flow rate of supercritical carbon dioxide.

[0069] It should be noted that the working fluid flow rate and temperature at the inlet of the turbine expander 1-2 increase rapidly, thereby meeting the demand for rapid load increases.

[0070] It should be noted that the combustion products in combustion chamber 2-1 increase the content of supercritical carbon dioxide working fluid in the system. The supercritical carbon dioxide working fluid contains water vapor. Most of the water vapor condenses into liquid in the first cooler 1-3 and then enters the water separator 1-4 together with the carbon dioxide. In the water separator 1-4, the condensate settles at the bottom of the tank and is discharged from the system through the pipe connected to the water discharge valve 1-6. The high-purity carbon dioxide flows to the compressor 1-5 through the pipe at the top of the water separator 1-4.

[0071] Furthermore, the height of the bottom drain outlet of the water separator 1-4 used to connect the water discharge valve 1-6, the height of the working fluid inlet of the water separator 1-4 used to connect the supercritical carbon dioxide outlet of the first cooler 1-3, and the height of the working fluid outlet of the water separator 1-4 used to connect the working fluid inlet of the compressor 1-5 gradually increase in sequence.

[0072] It should be noted that there are height requirements for the three pipe inlets and outlets on the water separator 1-4. The connection between the water discharge valve 1-6 and the water separator 1-4 is located at the bottom of the water separator 1-4; the connection between the compressor 1-5 and the water separator 1-4 is located at the top of the water separator 1-4; and the connection between the first cooler 1-3 and the water separator 1-4 is located in the middle of the water separator 1-4.

[0073] Among them, the high-pressure supercritical carbon dioxide (CO2) compressed by compressors 1-3 is cooled by the second cooler 3 and stored in the supercritical carbon dioxide storage tank 4. When the supercritical carbon dioxide working medium in the supercritical carbon dioxide storage tank 4 is insufficient, it can be used to replenish the system; of course, when the working medium is in excess, it can also be transferred to the outside.

[0074] Second, when the supplementary combustion supercritical carbon dioxide Brayton cycle system is in a steady state and does not require a rapid increase in output power, the indirect heating element 1-1 works independently, while the combustion chamber 2-1 does not work.

[0075] III. In this invention, the supercritical carbon dioxide storage tank 4 has the function of regulating the system output power. The supercritical carbon dioxide storage tank 4 includes the following operating modes:

[0076] Mode 1: When the supplementary combustion supercritical carbon dioxide Brayton cycle system needs to increase power, open the supply valve 4-1 of the supercritical carbon dioxide storage tank 4 to the inlet of the compressor 1-5 to replenish the working fluid to the system.

[0077] Mode 2: When the power of the supplementary combustion supercritical carbon dioxide Brayton cycle system needs to be reduced, open the charging valve 4-2 after the outlet of the supercritical carbon dioxide storage tank 4 to the compressor 1-5, so that the working fluid of the supercritical carbon dioxide closed Brayton cycle subsystem is charged into the supercritical carbon dioxide storage tank 4, thereby regulating the system power.

[0078] Fourth, in addition, when the indirect heating element 1-1 fails, the combustion chamber 2-1 is used as a backup heat source to independently provide heat to the supplementary combustion supercritical carbon dioxide Brayton cycle system, thereby ensuring that the supplementary combustion supercritical carbon dioxide Brayton cycle system can operate normally for a short period of time.

[0079] In other words, combustion chamber 2-1 can serve as a backup heat source in case of failure of indirect heating element 1-1, thereby maintaining normal system operation for a short period of time.

[0080] Compared with the prior art, the afterburning supercritical carbon dioxide Brayton cycle system provided by the present invention has the following beneficial effects:

[0081] This invention connects a combustion chamber in parallel with the indirect heating element of a supercritical carbon dioxide closed Brayton cycle subsystem, and introduces oxygen and purified hydrocarbon fuel for combustion. This enables the system to instantly and rapidly increase its output power while using indirect heating as the main heat source.

[0082] 2. The carbon dioxide produced during combustion in the combustion chamber can be easily collected and used as a supplementary working fluid for the system. After the water and carbon dioxide produced by fuel combustion are cooled and separated in the cooler, the carbon dioxide is stored in a supercritical carbon dioxide storage tank. This supercritical carbon dioxide storage tank serves two purposes: firstly, it temporarily stores carbon dioxide for replenishment of the system; secondly, it can charge or release supercritical carbon dioxide into the system, thereby regulating the system's output power.

[0083] 3. Furthermore, when the indirect heating source fails, the combustion chamber can independently serve as a backup heat source. Therefore, the entire system of this invention has greater flexibility, mobility, and reliability.

[0084] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A post-combustion supercritical carbon dioxide Brayton cycle system, characterized in that, It includes a supercritical carbon dioxide closed Brayton cycle subsystem, a combustion chamber (2-1), a second cooler (3), and a supercritical carbon dioxide storage tank (4). The supercritical carbon dioxide closed Brayton cycle subsystem includes a wall heater (1-1), a turbine expander (1-2), a first cooler (1-3), a water separator (1-4), a compressor (1-5), and a water discharge valve (1-6) connected in sequence. The supercritical carbon dioxide outlet of the indirect-contact heater (1-1) in the supercritical carbon dioxide closed Brayton cycle subsystem is connected to the supercritical carbon dioxide inlet of the combustion chamber (2-1) for supplying supercritical carbon dioxide to the combustion chamber (2-1). The fuel inlet of the combustion chamber (2-1) is used to introduce fuel (2-4). The combustion product outlet of the combustion chamber (2-1) is connected to the supercritical carbon dioxide inlet of the turbine expander (1-2); The working fluid outlet of the compressor (1-5) in the supercritical carbon dioxide closed Brayton cycle subsystem is connected to the working fluid inlet of the second cooler (3) for outputting compressed supercritical carbon dioxide to the second cooler (3). The working fluid outlet of the second cooler (3) is connected to the inlet of the supercritical carbon dioxide storage tank (4); The outlet of the supercritical carbon dioxide storage tank (4) is connected to the connecting pipe between the outlet of the water separator (1-4) and the inlet of the compressor (1-5); A supply valve (4-1) is installed on the connecting pipe between the outlet of the supercritical carbon dioxide storage tank (4) and the inlet of the compressor (1-5). A filling valve (4-2) is installed on the connecting pipe between the working fluid outlet of the second cooler (3) and the inlet of the supercritical carbon dioxide storage tank (4). The combustion chamber (2-1) is connected to the supercritical carbon dioxide closed Brayton cycle subsystem via a first three-way valve (2-2) and a second three-way valve (2-3). The inlet of the first three-way valve (2-2) is connected to the supercritical carbon dioxide outlet of the indirect-contact heater (1-1); The first outlet of the first three-way valve (2-2) is connected to the supercritical carbon dioxide inlet of the combustion chamber (2-1); The second outlet of the first three-way valve (2-2) is connected to the first inlet of the second three-way valve (2-3); The second inlet of the second three-way valve (2-3) is connected to the combustion product outlet of the combustion chamber (2-1); The outlet of the second three-way valve (2-3) is connected to the supercritical carbon dioxide inlet of the turbine expander (1-2); The afterburning supercritical carbon dioxide Brayton cycle system includes the following operating modes: During normal operation of the supercritical carbon dioxide closed Brayton cycle subsystem, if the system load demand of the supplementary combustion supercritical carbon dioxide Brayton cycle system increases rapidly, pure oxygen and purified hydrocarbon fuel are introduced into the combustion chamber (2-1). The supercritical carbon dioxide fluid flowing through the combustion chamber (2-1) burns rapidly and releases heat, causing the temperature of the supercritical carbon dioxide at the inlet of the turbine expander (1-2) to increase rapidly, thereby instantaneously increasing the system output power. At the same time, the speed of the compressor (1-5) is also increased to increase the flow rate of supercritical carbon dioxide. When the supplementary combustion supercritical carbon dioxide Brayton cycle system is in steady state and does not require a rapid increase in output power, the indirect heating element (1-1) works independently, while the combustion chamber (2-1) does not work. When the indirect heating element (1-1) fails, the combustion chamber (2-1) is used as a backup heat source to independently provide heat to the supplementary combustion supercritical carbon dioxide Brayton cycle system, thereby ensuring that the supplementary combustion supercritical carbon dioxide Brayton cycle system can operate normally for a short period of time. Mode 1: When the supplementary combustion supercritical carbon dioxide Brayton cycle system needs to increase power, open the supply valve (4-1) before the compressor (1-5) inlet of the supercritical carbon dioxide storage tank (4) to replenish the working fluid to the system; Mode 2: When the power of the supplementary combustion supercritical carbon dioxide Brayton cycle system needs to be reduced, open the charging valve (4-2) after the outlet of the supercritical carbon dioxide storage tank (4) to the compressor (1-5), so that the working fluid of the supercritical carbon dioxide closed Brayton cycle subsystem is charged into the supercritical carbon dioxide storage tank (4), which plays the role of regulating the power of the system.

2. The afterburning supercritical carbon dioxide Brayton cycle system as described in claim 1, characterized in that, For the supercritical carbon dioxide closed Brayton cycle subsystem, the working fluid outlet of the compressor (1-5) is connected to the supercritical carbon dioxide inlet of the indirect-contact heater (1-1). The supercritical carbon dioxide outlet of the indirect-contact heater (1-1) is connected to the supercritical carbon dioxide inlet of the turbine expander (1-2). The supercritical carbon dioxide outlet of the turbine expander (1-2) is connected to the supercritical carbon dioxide inlet of the first cooler (1-3). The supercritical carbon dioxide outlet of the first cooler (1-3) is connected to the working fluid inlet of the water separator (1-4); The working fluid outlet of the water separator (1-4) is connected to the working fluid inlet of the compressor (1-5).

3. The afterburning supercritical carbon dioxide Brayton cycle system as described in claim 1, characterized in that, The hot end inlet of the indirect heat exchanger (1-1) is connected to the heat source outlet of the external heat source system; The hot end outlet of the indirect-contact heater (1-1) is connected to the outside.

4. The afterburning supercritical carbon dioxide Brayton cycle system as described in claim 1, characterized in that, Fuel (2-4) is a mixture of pure oxygen and hydrocarbon fuels; The discharge port on the supercritical carbon dioxide storage tank (4) is connected to one end of the discharge valve (4-3); The other end of the discharge valve (4-3) is connected to the outside.

5. The afterburning supercritical carbon dioxide Brayton cycle system as described in claim 2, characterized in that, The drain outlet at the bottom of the water separator (1-4) is connected to one end of the water discharge valve (1-6); The other end of the water drain valve (1-6) is connected to the outside. The height of the bottom drain of the water separator (1-4) used to connect the water discharge valve (1-6), the height of the working medium inlet of the water separator (1-4) used to connect the supercritical carbon dioxide outlet of the first cooler (1-3), and the height of the working medium outlet of the water separator (1-4) used to connect the working medium inlet of the compressor (1-5) gradually increase in sequence.

Images