Device system for coupling sCO2 Brayton cycle with organic Rankine cycle and operation method

Abstract

The invention provides a device system for coupling an sCO2 Brayton cycle with an organic Rankine cycle and an operation method. The device system comprises an sCO2 Brayton cycle unit and an organic Rankine cycle unit, the organic Rankine cycle unit comprises a first organic working medium evaporation device and a second organic working medium evaporation device; the sCO2 Brayton cycle unit is connected with the organic Rankine cycle unit through the first organic working medium evaporation device and the second organic working medium evaporation device. The organic Rankine cycle unit is used for recycling waste heat of the sCO2 Brayton cycle unit and outputting electric energy, and the power generation capacity of the whole device system is improved; meanwhile, flexible adjustment of power generation output of the device system is achieved through all the shut-off valves and the adjusting valves, it is guaranteed that the device system runs more safely, effectively and economically, and the device system is suitable for large-range application and popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of waste heat recovery, and in particular to a device system and an operation method of a sCO2 Brayton cycle coupled with an organic Rankine cycle. Background Art

[0002] The Brayton cycle system can be divided into supercritical carbon dioxide (sCO2) Brayton cycle, air Brayton cycle and helium Brayton cycle according to the difference in working fluid. Among them, the supercritical carbon dioxide Brayton cycle has the advantages of high efficiency, compact structure and low water consumption, and is suitable for various energy systems such as solar energy, fossil fuels, nuclear power, waste heat utilization and geothermal energy. Since the critical point of carbon dioxide is close to the ambient temperature, the supercritical carbon dioxide cycle does not have the condensation phase change process of the steam Rankine cycle in the low temperature zone, and the heat recovery efficiency is higher. At the same time, the turbine inlet of the supercritical carbon dioxide cycle can reach a higher temperature than the steam Rankine cycle, and the system efficiency potential is higher. Compared with other working fluid Brayton cycles, the overall working pressure of the supercritical carbon dioxide cycle is higher than 7.4MPa, the working fluid density is high, the core equipment of the system is compact, the compressor works in the near-critical zone, the compression power consumption is low, and the cycle efficiency is higher. However, there is a large waste heat loss in the Brayton cycle power system alone.

[0003] CN111486067A discloses a geothermal-solar power generation system based on sCO2 Brayton cycle, including sCO2 Brayton cycle, CO2 plume geothermal system and tower solar system as auxiliary heat source. sCO2 Brayton cycle includes: turbine, high temperature regenerator, low temperature regenerator, cooler, main compressor and recompressor. CO2 plume geothermal system includes: injection well, production well and separator. Tower solar system includes solar tower, heliostat field, absorber, high temperature molten salt tank, low temperature molten salt tank, heat exchanger, molten salt pump and the like. The power generation system realizes the combination of CO2 storage system and geothermal exploitation system through the coupling of sCO2 recompression Brayton cycle, CO2 plume geothermal system and tower solar system, and at the same time improves the utilization rate of medium and low temperature geothermal resources and the thermal efficiency of the cycle, and reduces the cost of geothermal exploitation.

[0004] CN211950614U discloses a sCO2 Brayton cycle power generation device and a power generation system, wherein the power generation device comprises: a turbine, a generator, a compressor, a regenerator, a heater, a cooler and a CO2 buffer tank. The power generation device is pre-filled with CO2 for enabling the power generation device to operate at full power. When the power generation device is started, high-pressure CO2 is filled into the power generation device through the CO2 buffer tank to drive the turbine to rotate, thereby driving the compressor to rotate. When the outlet pressure of the compressor is higher than its inlet pressure, the turbine drives the compressor and the generator to rotate simultaneously, and the generator starts to generate electricity, thereby realizing self-starting of the power generation device, greatly reducing the control difficulty of the system, reducing the system's failure points, increasing the system's application scenarios, and increasing the system's adaptability.

[0005] CN113251462A discloses a combined heat and power system and method of Brayton cycle coupled with absorption refrigeration cycle, the system comprises a sCO2 Brayton cycle power generation and heating module and a lithium bromide absorption refrigeration module, the heat before condensation of the sCO2 Brayton cycle is transferred to the lithium bromide absorption refrigeration cycle and utilized in the generator, thereby driving the refrigeration cycle, while a part of the energy of the CO2 working fluid that has done work in the turbine is used for external heat supply; the system can reduce the loss of cold source, improve the energy utilization rate of the system, and achieve the effect of combined heat and power; the system has multiple operating modes such as power generation mode, combined heat and power mode, combined heat and power mode and combined heat and power.

[0006] However, the above-mentioned device system does not effectively recover and utilize the waste heat at the high-temperature heater before the turbine inlet and the waste heat at the cooler before the compressor inlet in the Brayton cycle power system. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a device system and an operation method of a sCO2 Brayton cycle coupled with an organic Rankine cycle, which uses an organic Rankine cycle unit to recycle the waste heat at the heating device before the turbine inlet and the waste heat at the cooling device before the compressor inlet in the sCO2 Brayton cycle unit and output electrical energy, thereby improving the power generation capacity of the entire device system.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a device system for coupling a sCO2 Brayton cycle with an organic Rankine cycle, the device system comprising a sCO2 Brayton cycle unit and an organic Rankine cycle unit;

[0010] The organic Rankine cycle unit comprises a first organic working fluid evaporation device and a second organic working fluid evaporation device; the sCO2 Brayton cycle unit is connected to the organic Rankine cycle unit via the first organic working fluid evaporation device and the second organic working fluid evaporation device respectively.

[0011] The sCO2 Brayton cycle coupled with organic Rankine cycle device system structure design of the present invention is reasonable, and the organic Rankine cycle technology is used to recover the waste heat. The waste heat of the heating medium at the hot side outlet of the heating device before the turbine inlet in the sCO2 Brayton cycle unit and the waste heat of the CO2 working fluid before the compressor inlet are used as heat sources. The organic working fluid is converted into organic working fluid steam in the first organic working fluid evaporation device and the second organic working fluid evaporation device, and then enters the organic working fluid turbine of the organic Rankine cycle unit to perform work and output electrical energy, thereby realizing the effective recovery and utilization of waste heat and improving the power generation capacity of the entire device system.

[0012] Preferably, the sCO2 Brayton cycle unit comprises a cyclically connected CO2 compressor, a heat recovery device, a heating device, a CO2 turbine, a heat recovery device and a CO2 cooling device.

[0013] Preferably, the first organic working fluid evaporation device is arranged on a bypass pipeline between the CO2 compressor and the heat recovery device.

[0014] Preferably, the second organic working fluid evaporation device is connected to a heating device.

[0015] Preferably, the organic Rankine cycle unit further comprises an organic working fluid turbine, an organic working fluid condensing device and an organic working fluid pump which are connected in sequence.

[0016] Preferably, the organic working fluid pump is connected to the first organic working fluid evaporation device and the second organic working fluid evaporation device respectively.

[0017] Preferably, the organic working fluid turbine is connected to the first organic working fluid evaporation device and the second organic working fluid evaporation device respectively.

[0018] Preferably, a regulating valve and a first shut-off valve are sequentially arranged between the organic working fluid pump and the first organic working fluid evaporation device.

[0019] Preferably, a second shut-off valve is provided between the organic working fluid pump and the second organic working fluid evaporation device.

[0020] Preferably, a third shut-off valve is provided between the heat recovery device and the first organic working fluid evaporation device.

[0021] Preferably, a fourth shut-off valve is provided between the heat recovery device and the CO2 cooling device.

[0022] Preferably, a fifth shut-off valve is provided between the first organic working medium evaporation device and the organic working medium turbine.

[0023] Preferably, a sixth shut-off valve is provided between the second organic working medium evaporation device and the organic working medium turbine.

[0024] The present invention can control the flow rate of the organic working fluid flowing through the first organic working fluid evaporation device and the second organic working fluid evaporation device by reasonably setting various shut-off valves and regulating valves, and adjust the output of the organic Rankine cycle system while ensuring that the output of the sCO2 Brayton cycle system remains unchanged, thereby flexibly adjusting the output of the device system of the sCO2 Brayton cycle coupled with the organic Rankine cycle.

[0025] In a second aspect, the present invention also provides an operating method for a device system of a sCO2 Brayton cycle coupled with an organic Rankine cycle as described in the first aspect, the operating method comprising an operating method of using a first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of a heat recovery device and an operating method of using a second organic working fluid evaporation device to recover the waste heat of the heating medium at the hot side of a heating device.

[0026] Preferably, the operating method of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device includes: closing the fourth shut-off valve, the sixth shut-off valve and the second shut-off valve, opening the third shut-off valve, the fifth shut-off valve and the first shut-off valve, and the organic working fluid enters the first organic working fluid evaporation device after being pressurized by the organic working fluid circulation pump, absorbs the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device and forms organic working fluid steam; the organic working fluid steam enters the organic working fluid turbine to perform work and output electrical energy, and the organic working fluid exhaust gas after the work enters the organic working fluid condensing device to be cooled, and after cooling, enters the organic working fluid circulation pump to be pressurized to complete the cycle.

[0027] Preferably, in the process of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device, the valve openings of the fourth shut-off valve and the third shut-off valve are adjusted to distribute the flow of the CO2 working fluid entering the CO2 cooling device and the organic working fluid evaporation device, thereby adjusting the output of the organic Rankine cycle system.

[0028] Preferably, in the process of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device, the frequency of the organic working fluid pump and the opening of the regulating valve are adjusted to adjust the organic working fluid flow rate so that the CO2 side outlet temperature of the first organic working fluid evaporation device meets the design value of the CO2 compressor inlet temperature.

[0029] Preferably, the operating method of using a second organic working fluid evaporation device to recover the waste heat of the heating medium on the hot side of the heating device includes: closing the third shut-off valve, the fifth shut-off valve, and the first shut-off valve, and opening the sixth shut-off valve, the second shut-off valve, and the fourth shut-off valve; the organic working fluid enters the second organic working fluid evaporation device after being pressurized by an organic working fluid circulation pump, absorbs the waste heat after the heating medium on the hot side of the heating device heats CO2 and forms organic working fluid steam; the organic working fluid steam enters the organic working fluid turbine to perform work and output electrical energy, and the organic working fluid exhaust gas after the work enters the organic working fluid condensing device to be cooled, and after cooling, enters the organic working fluid circulation pump to be pressurized to complete the cycle.

[0030] Preferably, in the process of using the second organic working fluid evaporation device to recover the waste heat of the heating medium on the hot side of the heating device, the frequency of the organic working fluid pump and the opening of the regulating valve are adjusted to adjust the organic working fluid flow rate and the heat exchange power of the second organic working fluid evaporation device, thereby adjusting the output power of the organic Rankine cycle unit.

[0031] The operating method of the sCO2 Brayton cycle coupled with organic Rankine cycle device system of the present invention effectively recovers and utilizes the waste heat at the heating device before the turbine inlet and the waste heat at the cooling device before the compressor inlet in the sCO2 Brayton cycle unit by controlling the opening and closing of each shut-off valve, thereby improving the power generation capacity of the system; at the same time, the system power generation output is flexibly adjusted by regulating the regulating valve, ensuring that the system operates more safely, efficiently and economically.

[0032] As a preferred technical solution of the present invention, the operating method includes an operating method of using a first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device and an operating method of using a second organic working fluid evaporation device to recover the waste heat of the heating medium at the hot side of the heating device;

[0033] The operation method of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device comprises: closing the fourth shut-off valve, the sixth shut-off valve and the second shut-off valve, opening the third shut-off valve, the fifth shut-off valve and the first shut-off valve, and the organic working fluid enters the first organic working fluid evaporation device after being pressurized by the organic working fluid circulation pump, absorbs the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device and forms organic working fluid steam; the organic working fluid steam enters the organic working fluid turbine to perform work and output electrical energy, and the organic working fluid exhaust gas after the work enters the organic working fluid condensing device to be cooled, and after cooling, enters the organic working fluid circulation pump to be pressurized to complete the cycle;

[0034] In the process of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device, the valve openings of the fourth shut-off valve and the third shut-off valve are adjusted to distribute the flow of the CO2 working fluid entering the CO2 cooling device and the organic working fluid evaporation device, and to adjust the output of the organic Rankine cycle system; the frequency of the organic working fluid pump and the opening of the regulating valve are adjusted to adjust the organic working fluid flow rate, so that the CO2 side outlet temperature of the first organic working fluid evaporation device meets the design value of the CO2 compressor inlet temperature;

[0035] The operating method of using the second organic working medium evaporation device to recover the waste heat of the heating medium on the hot side of the heating device comprises: closing the third shut-off valve, the fifth shut-off valve, and the first shut-off valve, opening the sixth shut-off valve, the second shut-off valve, and the fourth shut-off valve, the organic working medium enters the second organic working medium evaporation device after being pressurized by the organic working medium circulation pump, absorbs the waste heat after the heating medium on the hot side of the heating device heats CO2 and forms organic working medium steam; the organic working medium steam enters the organic working medium turbine to perform work and output electrical energy, the organic working medium exhaust gas after the work enters the organic working medium condensing device to cool, and after cooling, enters the organic working medium circulation pump to increase pressure to complete the cycle;

[0036] In the process of using the second organic working fluid evaporation device to recover the waste heat of the heating medium on the hot side of the heating device, the frequency of the organic working fluid pump and the opening of the regulating valve are adjusted to adjust the organic working fluid flow rate and the heat exchange power of the second organic working fluid evaporation device, thereby adjusting the output power of the organic Rankine cycle unit.

[0037] Compared with the prior art, the present invention has at least the following beneficial effects:

[0038] The sCO2 Brayton cycle coupled with organic Rankine cycle device system provided by the present invention recovers the waste heat of the sCO2 Brayton cycle unit through the organic Rankine cycle unit and outputs electrical energy, thereby improving the power generation capacity of the entire device system; at the same time, the working loop of the organic Rankine cycle unit is switched by various shut-off valves and regulating valves, thereby realizing flexible control of the system's power generation output. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of a device system for coupling a sCO2 Brayton cycle with an organic Rankine cycle in a specific embodiment of the present invention.

[0040] In the figure: 1-first organic working fluid evaporation device; 2-organic working fluid turbine; 3-organic working fluid condensation device; 4-organic working fluid pump; 5-regulating valve; 6-third shut-off valve; 7-fifth shut-off valve; 8-first shut-off valve; 9-sixth shut-off valve; 10-second shut-off valve 11-second organic working fluid evaporation device; 12-CO2 compressor; 13-heat recovery device; 14-heating device; 15-CO2 turbine; 16-fourth shut-off valve; 17-CO2 cooling device. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0042] The present invention is further described in detail below. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0043] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0044] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0045] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0046] As a specific embodiment of the present invention, a device system for coupling a sCO2 Brayton cycle with an organic Rankine cycle is provided, and its schematic diagram is as follows: Figure 1 shown.

[0047] The device system includes a sCO2 Brayton cycle unit and an organic Rankine cycle unit;

[0048] The organic Rankine cycle unit comprises a first organic working medium evaporation device 1 and a second organic working medium evaporation device 11;

[0049] The sCO2 Brayton cycle unit is connected to the organic Rankine cycle unit via the first organic working medium evaporation device 1 and the second organic working medium evaporation device 11 respectively.

[0050] The sCO2 Brayton cycle unit comprises a CO2 compressor 12, a heat recovery device 13, a heating device 14, a CO2 turbine 15, a heat recovery device 13 and a CO2 cooling device 17 which are cyclically connected.

[0051] The first organic working medium evaporation device 1 is arranged on a bypass pipeline between the CO 2 compressor 12 and the heat recovery device 13 .

[0052] The second organic working medium evaporation device 11 is connected to the heating device 14 .

[0053] The organic Rankine cycle unit also includes an organic working fluid turbine 2, an organic working fluid condensing device 3 and an organic working fluid pump 4 which are connected in sequence;

[0054] The organic working medium pump 4 is connected to the first organic working medium evaporation device 1 and the second organic working medium evaporation device 11 respectively;

[0055] The organic working medium turbine 2 is connected to the first organic working medium evaporation device 1 and the second organic working medium evaporation device 11 respectively.

[0056] A regulating valve 5 and a first shut-off valve 8 are sequentially arranged between the organic working medium pump 4 and the first organic working medium evaporation device 1;

[0057] A second shutoff valve 10 is provided between the organic working medium pump 4 and the second organic working medium evaporation device 11 .

[0058] A third shut-off valve 6 is provided between the heat recovery device 13 and the first organic working medium evaporation device 1;

[0059] A fourth shut-off valve 16 is provided between the heat recovery device 13 and the CO2 cooling device 17;

[0060] A fifth shut-off valve 7 is provided between the first organic working medium evaporation device 1 and the organic working medium turbine 2;

[0061] A sixth shut-off valve 9 is provided between the second organic working medium evaporation device 11 and the organic working medium turbine 2 .

[0062] As a specific embodiment of the present invention, an operating method of the above-mentioned sCO2 Brayton cycle coupled with an organic Rankine cycle device system is also provided, and the operating method includes an operating method of using a first organic working fluid evaporation device 1 to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device 13 and an operating method of using a second organic working fluid evaporation device 11 to recover the waste heat of the heating medium at the hot side of the heating device 14.

[0063] The operation method of using the first organic working medium evaporation device 1 to recover the CO2 working medium waste heat at the cold side outlet of the heat recovery device 13 includes: closing the fourth shut-off valve 16, the sixth shut-off valve 9 and the second shut-off valve 10, opening the third shut-off valve 6, the fifth shut-off valve 7 and the first shut-off valve 8, the organic working medium enters the first organic working medium evaporation device 1 after being pressurized by the organic working medium circulation pump 4, absorbs the CO2 working medium waste heat at the cold side outlet of the heat recovery device 13 and forms organic working medium steam; the organic working medium steam enters the organic working medium turbine 2 to perform work and output electrical energy, the organic working medium exhaust gas after the work enters the organic working medium condensing device 3 to be cooled, and after cooling, enters the organic working medium circulation pump 4 to be pressurized to complete the cycle;

[0064] In the process of using the first organic working fluid evaporation device 1 to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device 13, the valve openings of the fourth shut-off valve 16 and the third shut-off valve 6 are adjusted to distribute the flow of the CO2 working fluid entering the CO2 cooling device 17 and the organic working fluid evaporation device 1, and to adjust the output of the organic Rankine cycle system; the frequency of the organic working fluid pump 4 and the opening of the regulating valve 5 are adjusted to adjust the organic working fluid flow rate, so that the CO2 side outlet temperature of the first organic working fluid evaporation device 1 meets the design value of the CO2 compressor 12 inlet temperature;

[0065] The operation method of using the second organic working medium evaporation device 11 to recover the waste heat of the heating medium on the hot side of the heating device 14 includes: closing the third shut-off valve 6, the fifth shut-off valve 7, and the first shut-off valve 8, and opening the sixth shut-off valve 9, the second shut-off valve 10, and the fourth shut-off valve 16; the organic working medium enters the second organic working medium evaporation device 11 after being pressurized by the organic working medium circulation pump 4, absorbs the waste heat after the heating medium on the hot side of the heating device 14 heats CO2, and forms organic working medium steam; the organic working medium steam enters the organic working medium turbine 2 to perform work and output electrical energy, and the organic working medium exhaust gas after the work enters the organic working medium condensing device 3 to cool, and after cooling, enters the organic working medium circulation pump 4 to increase pressure, completing the cycle;

[0066] In the process of using the second organic working medium evaporation device 11 to recover the waste heat of the heating medium on the hot side of the heating device 14, the frequency of the organic working medium pump 4 and the opening of the regulating valve 5 are adjusted to adjust the organic working medium flow rate and the heat exchange power of the second organic working medium evaporation device 11, thereby adjusting the output power of the organic Rankine cycle unit.

[0067] In summary, the sCO2 Brayton cycle coupled with organic Rankine cycle device system provided by the present invention has a reasonable structural design and convenient operation and regulation. The organic Rankine cycle unit is used to recover the waste heat of the sCO2 Brayton cycle unit and output electrical energy, thereby improving the power generation capacity of the entire device system. At the same time, the system power generation output can be flexibly adjusted through various shut-off valves and regulating valves, ensuring that the system operates more safely, efficiently and economically, and is suitable for large-scale promotion and application.

[0068] The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the components selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0069] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A sCO2 Brayton cycle coupled with an organic Rankine cycle, characterized in that: The device system includes a sCO2 Brayton cycle unit and an organic Rankine cycle unit; The organic Rankine cycle unit comprises a first organic working fluid evaporation device and a second organic working fluid evaporation device; the sCO2 Brayton cycle unit is connected to the organic Rankine cycle unit via the first organic working fluid evaporation device and the second organic working fluid evaporation device respectively.

2. The device system according to claim 1, characterized in that: The sCO2 Brayton cycle unit comprises a CO2 compressor, a heat recovery device, a heating device, a CO2 turbine, a heat recovery device and a CO2 cooling device which are cyclically connected.

3. The device system according to claim 1 or 2, characterized in that: The first organic working medium evaporation device is arranged on a bypass pipeline between the CO2 compressor and the heat recovery device.

4. The device system according to any one of claims 1 to 3, characterized in that: The second organic working medium evaporating device is connected to the heating device.

5. The device system according to any one of claims 1 to 4, characterized in that: The organic Rankine cycle unit also includes an organic working fluid turbine, an organic working fluid condensing device and an organic working fluid pump which are connected in sequence; Preferably, the organic working fluid pump is connected to the first organic working fluid evaporation device and the second organic working fluid evaporation device respectively; Preferably, the organic working fluid turbine is connected to the first organic working fluid evaporation device and the second organic working fluid evaporation device respectively.

6. The device system according to claim 5, characterized in that: A regulating valve and a first shut-off valve are sequentially arranged between the organic working fluid pump and the first organic working fluid evaporation device; Preferably, a second shut-off valve is provided between the organic working fluid pump and the second organic working fluid evaporation device.

7. The device system according to any one of claims 1 to 6, characterized in that: A third shut-off valve is provided between the heat recovery device and the first organic working medium evaporation device; Preferably, a fourth shut-off valve is provided between the heat recovery device and the CO2 cooling device; Preferably, a fifth shut-off valve is provided between the first organic working medium evaporation device and the organic working medium turbine; Preferably, a sixth shut-off valve is provided between the second organic working medium evaporation device and the organic working medium turbine.

8. A method for operating a sCO2 Brayton cycle coupled with an organic Rankine cycle device system as claimed in any one of claims 1 to 7, characterized in that: The operation method includes an operation method of using a first organic working medium evaporation device to recover the waste heat of CO2 working medium at the cold side outlet of a heat recovery device and an operation method of using a second organic working medium evaporation device to recover the waste heat of a heating medium at the hot side of a heating device.

9. The operating method according to claim 8, characterized in that: The operation method of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device comprises: closing the fourth shut-off valve, the sixth shut-off valve and the second shut-off valve, opening the third shut-off valve, the fifth shut-off valve and the first shut-off valve, and the organic working fluid enters the first organic working fluid evaporation device after being pressurized by the organic working fluid circulation pump, absorbs the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device and forms organic working fluid steam; the organic working fluid steam enters the organic working fluid turbine to perform work and output electrical energy, and the organic working fluid exhaust gas after the work enters the organic working fluid condensing device to be cooled, and after cooling, enters the organic working fluid circulation pump to be pressurized to complete the cycle; Preferably, in the process of using the first organic working medium evaporation device to recover the waste heat of the CO2 working medium at the cold side outlet of the heat recovery device, the valve openings of the fourth shut-off valve and the third shut-off valve are adjusted to distribute the flow of the CO2 working medium entering the CO2 cooling device and the organic working medium evaporation device, and adjust the output of the organic Rankine cycle system; Preferably, in the process of using the first organic working fluid evaporation device to recover the waste heat of the CO2 working fluid at the cold side outlet of the heat recovery device, the frequency of the organic working fluid pump and the opening of the regulating valve are adjusted to adjust the organic working fluid flow rate so that the CO2 side outlet temperature of the first organic working fluid evaporation device meets the design value of the CO2 compressor inlet temperature.

10. The operating method according to claim 8 or 9, characterized in that: The operating method of using the second organic working medium evaporation device to recover the waste heat of the heating medium on the hot side of the heating device comprises: closing the third shut-off valve, the fifth shut-off valve, and the first shut-off valve, opening the sixth shut-off valve, the second shut-off valve, and the fourth shut-off valve, the organic working medium enters the second organic working medium evaporation device after being pressurized by the organic working medium circulation pump, absorbs the waste heat after the heating medium on the hot side of the heating device heats CO2 and forms organic working medium steam; the organic working medium steam enters the organic working medium turbine to perform work and output electrical energy, the organic working medium exhaust gas after the work enters the organic working medium condensing device to cool, and after cooling, enters the organic working medium circulation pump to increase pressure to complete the cycle; Preferably, in the process of using the second organic working fluid evaporation device to recover the waste heat of the heating medium on the hot side of the heating device, the frequency of the organic working fluid pump and the opening of the regulating valve are adjusted to adjust the organic working fluid flow rate and the heat exchange power of the second organic working fluid evaporation device, thereby adjusting the output power of the organic Rankine cycle unit.

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