Device system and operating method for coupling a gas turbine to a carbon dioxide rankine cycle

Abstract

This invention provides a device system and operating method for a gas turbine coupled with a carbon dioxide Rankine cycle. The device system includes a gas turbine subsystem and a supercritical carbon dioxide Rankine dual-turbine subsystem. The gas turbine subsystem and the supercritical carbon dioxide Rankine dual-turbine subsystem are connected via a flue gas duct. The flue gas duct is sequentially connected to a first heat exchanger, a second heat exchanger, and a third heat exchanger within the supercritical carbon dioxide Rankine dual-turbine subsystem. The device system of this invention achieves good heat matching, improves energy utilization efficiency, and has prospects for large-scale application.

Description

Technical Field

[0001] This invention relates to the field of new energy power generation technology, and in particular to a device system and operating method for coupling a gas turbine with a carbon dioxide Rankine cycle. Background Technology

[0002] A gas turbine is a power machine that converts the thermal energy of high-temperature gas into mechanical work. It is characterized by high efficiency, cleanliness, flexible starting, and compact structure. Gas turbines support the combustion of various fuels, including various combustible gaseous and liquid fuels, with natural gas being the primary fuel. Gas turbine power generation can quickly regulate peak demand and promote the construction of new power systems; however, the combustion process of natural gas still produces carbon dioxide emissions. Blending natural gas with hydrogen or replacing natural gas with hydrogen can effectively reduce carbon dioxide emissions from gas turbines.

[0003] CN113756954A discloses a gas turbine power generation system and method. The gas turbine power generation system includes a renewable energy power generation device, a hydrogen production device, an air energy storage device, a gas turbine, and a first turbine. The renewable energy power generation device is connected to the hydrogen production device, and the air energy storage device is also connected to the hydrogen production device. The gas turbine is connected to both the hydrogen production device and the air energy storage device. The gas turbine can generate electricity using hydrogen produced by the hydrogen production device and air and oxygen from the air energy storage device. The first turbine can generate electricity by using the exhaust gas emitted by the gas turbine and the air and oxygen from the air energy storage device. This gas turbine power generation system has high power generation efficiency and can convert intermittent, fluctuating renewable energy power into stable power with rotational inertia under zero-carbon conditions.

[0004] CN114483307A discloses an efficiency improvement system and control method for a hydrogen fuel cell gas turbine. By setting at least one heat exchange section, which extracts the cold energy from the cryogenic hydrogen and cools the gas participating in the work within the gas turbine, the cooled gas improves the gas turbine's efficiency. Furthermore, a direct-flow component is provided to control whether the cryogenic hydrogen flows directly to the heat exchange section or bypasses it, thus controlling whether the cryogenic hydrogen undergoes heat exchange. Simultaneously, after absorbing heat, the cryogenic hydrogen's temperature increases, further enhancing its combustion efficiency when entering the gas turbine's combustion chamber. This improves the overall efficiency of the gas turbine, solving the technical problem that when using high-pressure hydrogen storage or cryogenic liquid hydrogen as a hydrogen source, the low temperature of the supplied hydrogen necessitates the absorption of some of the heat released during combustion, leading to reduced gas turbine efficiency.

[0005] However, the energy utilization efficiency of the above system needs further improvement. Therefore, developing a gas turbine coupled with a Rankine cycle carbon dioxide system and its operation method is of great significance for achieving better energy efficiency. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a device system and operation method for a gas turbine coupled with a carbon dioxide Rankine cycle. The flue gas generated by the gas turbine subsystem passes through a three-stage heat exchange device to exchange heat with carbon dioxide, making reasonable use of the heat of the flue gas. CO2 undergoes a three-stage heating and two-stage reheating process in the supercritical carbon dioxide Rankine dual turbine subsystem, which significantly improves the energy cycle efficiency of the entire device system.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a device system for coupling a gas turbine with a carbon dioxide Rankine cycle, characterized in that the device system includes a gas turbine subsystem and a supercritical carbon dioxide Rankine dual-turbine subsystem; the gas turbine subsystem and the supercritical carbon dioxide Rankine dual-turbine subsystem are connected by a flue gas duct; the flue gas duct is sequentially connected to a first heat exchanger, a second heat exchanger and a third heat exchanger within the supercritical carbon dioxide Rankine dual-turbine subsystem.

[0009] In the gas turbine-coupled Rankine cycle system of this invention, the flue gas generated by the gas turbine subsystem first enters the gas turbine to perform work, and then enters the first, second, and third heat exchangers within the supercritical Rankine dual-turbine subsystem, where it exchanges heat with carbon dioxide, thus making efficient use of the flue gas's heat. The heated carbon dioxide then enters the two supercritical CO2 turbines within the supercritical Rankine dual-turbine subsystem to perform work, significantly improving the energy efficiency of the entire system. Compared to the traditional gas turbine-coupled supercritical Brayton cycle system, the gas turbine-coupled supercritical Rankine cycle system of this invention produces more power output from the turbines.

[0010] The main function of the pre-cooling device and the second intermediate cooling device in this invention is to reduce the power consumption of the CO2 compression device and the second CO2 conveying device.

[0011] The gas turbine subsystem in this invention has high operating parameters, mainly reflected in the compressor pressure ratio of 20~45 and the combustion chamber temperature of 1600~1800℃.

[0012] Preferably, the gas turbine subsystem includes a compressor, a combustion chamber, and a gas turbine connected in sequence.

[0013] Preferably, the compressor is connected to an air delivery pipeline.

[0014] Preferably, the compressor is an axial flow compressor, and the compressor stages can have multi-stage extraction cooling.

[0015] Preferably, the combustion chamber is connected to a gas delivery pipeline.

[0016] Preferably, the supercritical carbon dioxide Rankine dual-turbo subsystem includes a first heat exchange module and a second heat exchange module connected in series via a first pipeline.

[0017] Preferably, the first heat exchange module includes a third heat exchange device and a first regenerating device connected in parallel.

[0018] Preferably, the second heat exchange module includes a second heat exchange device and a second regeneration device connected in parallel.

[0019] Preferably, the supercritical carbon dioxide Rankine dual turbine subsystem includes a CO2 compression device, a first intermediate cooling device, a first CO2 conveying device, a second intermediate cooling device, and a second CO2 conveying device connected in sequence.

[0020] Preferably, the CO2 compression device includes a centrifugal CO2 compression device.

[0021] Preferably, the second CO2 conveying device is connected in sequence to the first heat exchange module and the second heat exchange module.

[0022] Preferably, the second heat exchange module is connected to the first heat exchange device and the first supercritical CO2 turbine via a second pipeline.

[0023] Preferably, the first supercritical CO2 turbine is connected in sequence to the first regenerating device, the precooling device, and the CO2 compression device.

[0024] Preferably, the first heat exchange device is connected in sequence to the second supercritical CO2 turbine, the second regeneration device, the first regeneration device, the precooling device, and the CO2 compression device.

[0025] The supercritical carbon dioxide Rankine dual-turbine subsystem of the present invention includes a first supercritical CO2 turbine and a second supercritical CO2 turbine. The dual turbines produce more power, and the CO2 at the outlets of both turbines expands to a subcritical state, which further increases the power output of the turbines.

[0026] Preferably, the first heat exchange device includes any one or a combination of at least two of shell-and-tube heat exchangers, plate heat exchangers, or plate-fin heat exchangers.

[0027] Preferably, the second heat exchange device includes any one or a combination of at least two of shell-and-tube heat exchangers, plate heat exchangers, or plate-fin heat exchangers.

[0028] Preferably, the third heat exchange device includes any one or a combination of at least two of shell-and-tube heat exchangers, plate heat exchangers, or plate-fin heat exchangers.

[0029] In a second aspect, the present invention also provides a method for operating a gas turbine coupled with a carbon dioxide Rankine cycle device system as described in the first aspect, the method comprising:

[0030] Air supplied by the air supply pipeline enters the combustion chamber via a compressor, where it is burned with gas supplied by the gas supply pipeline. The resulting flue gas enters the gas turbine to perform work. The flue gas discharged from the gas turbine passes through the first heat exchanger, the second heat exchanger, and the third heat exchanger in sequence to exchange heat with CO2 before being discharged into the atmosphere.

[0031] After being pressurized by the CO2 compression unit, the CO2 enters the first intermediate cooling unit and is cooled into a liquid phase. It then sequentially enters the first CO2 conveying unit, the second intermediate cooling unit, and the second CO2 conveying unit. It is then split into two streams, one entering the third heat exchange unit and the other the first regenerating unit for heat exchange, before converging into the first pipeline. It is then split into two streams again, one entering the second heat exchange unit and the other the second regenerating unit for heat exchange, before converging into the second pipeline. Finally, it splits into two streams once more: one enters the first heat exchange unit for heat exchange, becoming the first CO2; the other enters the first supercritical CO2 turbine to perform work, becoming the second CO2.

[0032] After the first CO2 enters the second supercritical CO2 turbine to do work, it enters the second regenerator and the first regenerator in sequence for heat exchange, and then enters the CO2 compression unit through the precooling unit; the second CO2 enters the first regenerator for heat exchange, and then enters the CO2 compression unit through the precooling unit, thus completing the Rankine cycle of carbon dioxide.

[0033] In the operation method of the gas turbine coupled CO2 Rankine cycle device system described in this invention, CO2 is divided into two paths via a second CO2 conveying device. One path of CO2 enters a third heat exchange device to exchange heat with flue gas, while the other path enters a first regenerative device, where it exchanges heat with CO2 discharged from the first supercritical CO2 turbine and CO2 discharged from the second regenerative device, before converging into a first pipeline. Then, it is further divided into two paths: one path enters a second heat exchange device to exchange heat with flue gas, and the other path enters a second regenerative device to exchange heat with CO2 discharged from the first supercritical CO2 turbine, before converging into a second pipeline. Finally, it is divided again: one path enters the first heat exchange device to exchange heat with flue gas, becoming the first CO2; the other path enters the first supercritical CO2 turbine to perform work, becoming the second CO2. The CO2 undergoes a three-stage heating and two-stage regenerative process, achieving better heat matching and significantly improving the overall cycle efficiency of the device system.

[0034] Preferably, the pressure ratio of the compressor is 20 to 45, for example, it can be 20, 25, 30, 35, 40 or 45, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the temperature of the flue gas generated in the combustion chamber is 1600~1800℃, for example, it can be 1600℃, 1650℃, 1700℃, 1750℃ or 1800℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] The flue gas generated in the combustion chamber is preferably 1600~1800℃. Excessively high temperatures will affect the normal operation of the gas turbine blades.

[0037] Preferably, the fuel gas includes hydrogen and natural gas.

[0038] Preferably, the volume percentage of hydrogen in the gas is 5% to 100%, for example, it can be 5%, 10%, 20%, 50%, 80% or 100%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0039] Preferably, the pressure of the flue gas discharged from the gas turbine is ≥1.03 bar, for example, it can be 1.03 bar, 10.5 bar, 1.08 bar, 1.1 bar, 1.12 bar or 1.15 bar, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] Preferably, the temperature of the flue gas discharged from the gas turbine is ≥600℃, for example, it can be 600℃, 620℃, 650℃, 700℃, 800℃ or 900℃, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] Preferably, the pressure of CO2 at the outlet of the first CO2 conveying device is 10~25MPa, for example, it can be 10MPa, 13MPa, 16MPa, 19MPa, 23MPa or 25MPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0042] Preferably, the CO2 pressure at the outlet of the second CO2 conveying device is 25~36MPa, for example, it can be 25MPa, 27MPa, 29MPa, 31MPa, 33MPa or 36MPa, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0043] Preferably, the CO2 flow rate at the inlet of the first supercritical CO2 turbine is 380~415 kg / s, for example, it can be 380 kg / s, 385 kg / s, 390 kg / s, 395 kg / s, 400 kg / s or 415 kg / s, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] Preferably, the temperature of the CO2 at the inlet of the second supercritical CO2 turbine is 550~610℃, for example, it can be 550℃, 560℃, 570℃, 580℃, 590℃, 600℃ or 610℃, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0045] Preferably, the pressure of CO2 at the outlet of the second supercritical CO2 turbine is 4.5~7.3MPa, for example, it can be 4.5MPa, 5.1MPa, 5.7MPa, 6.4MPa, 6.9MPa or 7.3MPa, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0046] As a preferred technical solution of the present invention, the operating method includes:

[0047] Air supplied through an air delivery pipeline enters the combustion chamber via a compressor with a pressure ratio of 20-45, where it combusts with fuel gas supplied through a gas delivery pipeline, producing flue gas at a temperature of 1600-1800℃. This flue gas then enters a gas turbine to perform work. The flue gas discharged from the gas turbine, with a pressure ≥1.03 bar and a temperature ≥600℃, sequentially passes through a first heat exchanger, a second heat exchanger, and a third heat exchanger to exchange heat with CO2 before being discharged into the atmosphere. The fuel gas includes hydrogen and natural gas; the volume percentage of hydrogen in the fuel gas is 5-100%.

[0048] After being pressurized by the CO2 compression unit, the CO2 enters the first intermediate cooling unit and is cooled into a liquid phase. It then sequentially enters the first CO2 conveying unit, the second intermediate cooling unit, and the second CO2 conveying unit. It is then split into two streams, one entering the third heat exchange unit and the other the first regenerating unit for heat exchange, before converging into the first pipeline. It is then split into two streams again, one entering the second heat exchange unit and the other the second regenerating unit for heat exchange, before converging into the second pipeline. Finally, it splits into two streams once more: one enters the first heat exchange unit for heat exchange, becoming the first CO2; the other enters the first supercritical CO2 turbine to perform work, becoming the second CO2.

[0049] After the first CO2 enters the second supercritical CO2 turbine to do work, it enters the second regenerator and the first regenerator in sequence for heat exchange, and then enters the CO2 compression unit through the precooling unit; the second CO2 enters the first regenerator for heat exchange, and then enters the CO2 compression unit through the precooling unit, thus completing the CO2 Rankine cycle.

[0050] The outlet CO2 pressure of the first CO2 conveying device is 10~25MPa; the outlet CO2 pressure of the second CO2 conveying device is 25~36MPa; the inlet CO2 flow rate of the first supercritical CO2 turbine is 380~415kg / s; the inlet CO2 temperature of the second supercritical CO2 turbine is 550~610℃; and the outlet CO2 pressure of the second supercritical CO2 turbine is 4.5~7.3MPa.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] The gas turbine coupled with a carbon dioxide Rankine cycle device system provided by this invention has a reasonable design. The supercritical carbon dioxide Rankine dual turbine subsystem includes a two-stage intermediate cooling device, a three-stage heat exchange device, a two-stage regeneration device, and a two-stage supercritical CO2 turbine. In the operation method, the CO2 at the outlet of the second CO2 conveying device undergoes a three-stage heating and two-stage regeneration process, achieving good heat matching and improving the energy utilization efficiency of the device system. Attached Figure Description

[0053] Figure 1This is a schematic diagram of the structure of the device system that couples a gas turbine with a carbon dioxide Rankine cycle in a specific implementation.

[0054] Figure 2 This is a temperature-entropy diagram of the carbon dioxide cycle in the supercritical carbon dioxide Rankine dual turbine system in a specific implementation.

[0055] Figure 3 The graph shows the thermal efficiency of the gas turbine coupled with the carbon dioxide Rankine cycle in the specific implementation scheme and the thermal efficiency of the supercritical carbon dioxide Rankine dual-turbo subsystem as a function of the compressor pressure ratio.

[0056] In the diagram: 1-Compressor; 2-Combustion chamber; 3-Gas turbine; 4-First heat exchanger; 5-Second heat exchanger; 6-Third heat exchanger; 7-Second supercritical CO2 turbine; 8-First supercritical CO2 turbine; 9-Second regeneration device; 10-First regeneration device; 11-Precooling device; 12-CO2 compression device; 13-First intermediate cooling device; 14-First CO2 conveying device; 15-Second intermediate cooling device; 16-Second CO2 conveying device; 17-First pipeline; 18-Second pipeline. Detailed Implementation

[0057] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0058] The present invention will now be described in further detail. However, the examples described below are merely 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 is determined by the claims.

[0059] It should be understood that in the description of this invention, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0060] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] Those skilled in the art should understand that the present invention necessarily includes the necessary pipelines, conventional valves and general pump equipment for achieving process integrity, but the above content is not the main inventive point of the present invention. Those skilled in the art can add layouts based on process flow and equipment structure selection, and the present invention does not make any special requirements or specific limitations in this regard.

[0062] As a specific embodiment of the present invention, a device system for coupling a gas turbine with a carbon dioxide Rankine cycle is provided, the structural schematic diagram of which is shown below. Figure 1 As shown.

[0063] The device system includes a gas turbine subsystem and a supercritical carbon dioxide Rankine dual turbine subsystem; the gas turbine subsystem and the supercritical carbon dioxide Rankine dual turbine subsystem are connected by a flue gas duct; the flue gas duct is sequentially connected to a first heat exchanger 4, a second heat exchanger 5 and a third heat exchanger 6 within the supercritical carbon dioxide Rankine dual turbine subsystem.

[0064] The gas turbine subsystem includes a compressor 1, a combustion chamber 2, and a gas turbine 3 connected in sequence.

[0065] The compressor 1 is connected to the air delivery pipeline; the compressor 1 is an axial flow type. The combustion chamber 2 is connected to the gas delivery pipeline.

[0066] The supercritical carbon dioxide Rankine dual-turbine subsystem includes a first heat exchange module and a second heat exchange module connected in series via a first pipe 17; the first heat exchange module includes a third heat exchange device 6 and a first regenerator 10 connected in parallel; the second heat exchange module includes a second heat exchange device 5 and a second regenerator 9 connected in parallel.

[0067] The supercritical carbon dioxide Rankine dual turbine subsystem includes a precooling device 11, a CO2 compression device 12, a first intermediate cooling device 13, a first CO2 conveying device 14, a second intermediate cooling device 15, and a second CO2 conveying device 16 connected in sequence.

[0068] The CO2 compression device 12 includes a centrifugal CO2 compression device; the second CO2 conveying device 16 is connected to the first heat exchange module and the second heat exchange module in sequence.

[0069] The second heat exchange module is connected to the first heat exchange device 4 and the first supercritical CO2 turbine 8 via the second pipe 18; the first supercritical CO2 turbine 8 is connected to the first regeneration device 10 and the precooling device 11 in sequence.

[0070] The first heat exchange device 4 is connected in sequence to the second supercritical CO2 turbine 7, the second regeneration device 9, the first regeneration device 10, and the precooling device 11.

[0071] The first heat exchange device 4 is a shell-and-tube heat exchanger; the second heat exchange device 5 is a plate heat exchanger; and the third heat exchange device 6 is a plate-fin heat exchanger.

[0072] As a specific embodiment of the present invention, an operating method for the above-mentioned gas turbine coupled with a carbon dioxide Rankine cycle device system is provided, characterized in that the operating method includes:

[0073] Air supplied by the air supply pipeline enters the combustion chamber 2 via a compressor 1 with a pressure ratio of 35.6, where it is combusted with the fuel gas supplied by the gas supply pipeline. The resulting flue gas, with a temperature of 1800°C, enters the gas turbine 3 to perform work. The flue gas discharged from the gas turbine 3, with a pressure ≥1.03 bar and a temperature ≥600°C, passes through the first heat exchanger 4, the second heat exchanger 5, and the third heat exchanger 6 in sequence to exchange heat with CO2 before being discharged into the atmosphere. The fuel gas is 100% hydrogen by volume, with a lower heating value of 119906 kJ / kg.

[0074] After being pressurized by the CO2 compression device 12, the CO2 enters the first intermediate cooling device 13 and is cooled into a liquid phase. It then sequentially enters the first CO2 conveying device 14, the second intermediate cooling device 15, and the second CO2 conveying device 16, with a CO2 pressure of 34 MPa. It is then divided into two paths: one path enters the third heat exchange device 6 to exchange heat with the flue gas, and the other path enters the first regeneration device 10 to exchange heat with the CO2 discharged from the first supercritical CO2 turbine 8 and the CO2 discharged from the second regeneration device 9, before converging into the first pipeline 17. It is then further divided into two paths: one path enters the second heat exchange device 5 to exchange heat with the flue gas, and the other path enters the second regeneration device 9 to exchange heat with the CO2 discharged from the first supercritical CO2 turbine 8, before converging into the second pipeline 18. Finally, it is divided again: one path enters the first heat exchange device 4 to exchange heat with the flue gas, becoming the first CO2; the other path enters the first supercritical CO2 turbine 8 to perform work, becoming the second CO2.

[0075] After the first CO2 enters the second supercritical CO2 turbine 7 to do work, it enters the second regenerator 9 and the first regenerator 10 in sequence for heat exchange, and then enters the CO2 compression unit 12 through the precooling unit 11; after the second CO2 enters the first regenerator 10 for heat exchange, it enters the CO2 compression unit 12 through the precooling unit 11, thus completing the CO2 Rankine cycle.

[0076] The CO2 pressure at the outlet of the first CO2 conveying device is 14 MPa; the CO2 pressure at the outlet of the second CO2 conveying device is 25 MPa; the CO2 flow rate at the inlet of the first supercritical CO2 turbine is 400 kg / s; the CO2 temperature at the inlet of the second supercritical CO2 turbine is 610 °C; and the CO2 pressure at the outlet of the second supercritical CO2 turbine is 5.7 MPa.

[0077] In this specific embodiment, the inlet flow rate of the CO2 compression device is 1060 kg / s. The CO2 is split into two streams from the second CO2 conveying device, which enter the third heat exchange device and the first regenerating device for heat exchange, respectively, with a CO2 split ratio of 0.358. The CO2 is also split into two streams through the first pipeline, which enter the second heat exchange device and the second regenerating device for heat exchange, respectively, with a CO2 split ratio of 0.495. Finally, the CO2 is split into two streams through the second pipeline, with one stream entering the first heat exchange device for heat exchange and the other stream entering the first supercritical CO2 turbine for work, with a CO2 split ratio of 0.377.

[0078] Calculate the overall thermal efficiency of the device system in this specific embodiment. In the formula This refers to the net power of the gas turbine subsystem. The net power of the bottom cycle is calculated, resulting in a total thermal efficiency of 69.04% (lower heating value). The net thermal power of the system is 620.7MW, of which the net power of the gas turbine subsystem is 420.7MW and the net power of the supercritical carbon dioxide Rankine dual turbine subsystem is 181MW. The temperature of the flue gas discharged into the atmosphere after heat exchange with CO2 in the third heat exchange unit is 52.8℃.

[0079] In this specific embodiment, the temperature-entropy diagram of the carbon dioxide cycle in the supercritical carbon dioxide Rankine dual-turbine system is as follows: Figure 2 As shown. From Figure 2 As can be seen, in this specific embodiment, the CO2 from the outlets of the first and second supercritical CO2 turbines is pressurized by the CO2 compression device, then cooled into a liquid phase by the first intermediate cooling device, and then pressurized by the first and second CO2 conveying devices. The lower limit of the entire temperature entropy diagram is lowered, and the average heat release temperature of the CO2 cycle in the supercritical carbon dioxide Rankine dual turbine subsystem is reduced, which is beneficial to both power output and efficiency.

[0080] In this specific embodiment, the thermal efficiency of the gas turbine coupled with a carbon dioxide Rankine cycle system and the thermal efficiency of the supercritical carbon dioxide Rankine dual-turbo subsystem as a function of compressor pressure ratio are shown in the following graphs. Figure 3 As shown. From Figure 3 It can be seen that as the compressor pressure ratio increases, the thermal efficiency of the gas turbine coupled with the carbon dioxide Rankine cycle system first increases and then slowly decreases, and the thermal efficiency of the supercritical carbon dioxide Rankine dual turbine subsystem gradually decreases.

[0081] The applicant declares that the detailed structural features of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions for the components selected in the present invention, additions of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0082] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A device system for coupling a gas turbine with a carbon dioxide Rankine cycle, characterized in that, The device system includes a gas turbine subsystem and a supercritical carbon dioxide Rankine dual turbine subsystem; the gas turbine subsystem and the supercritical carbon dioxide Rankine dual turbine subsystem are connected by a flue gas duct; the flue gas duct is sequentially connected to a first heat exchanger, a second heat exchanger and a third heat exchanger within the supercritical carbon dioxide Rankine dual turbine subsystem. The supercritical carbon dioxide Rankine dual turbine subsystem includes a first heat exchange module and a second heat exchange module connected in series via a first pipeline. The first heat exchange module includes a third heat exchange device connected in parallel to the first regenerative device; The second heat exchange module includes a second heat exchange device and a second regeneration device connected in parallel. The supercritical carbon dioxide Rankine dual turbine subsystem includes a CO2 compression device, a first intermediate cooling device, a first CO2 conveying device, a second intermediate cooling device, and a second CO2 conveying device connected in sequence. The second CO2 conveying device is connected in sequence to the first heat exchange module and the second heat exchange module; The second heat exchange module is connected to the first heat exchange device and the first supercritical CO2 turbine via a second pipeline; The first supercritical CO2 turbine is connected in sequence to the first regenerating device, the precooling device, and the CO2 compression device; The first heat exchange device is connected in sequence to the second supercritical CO2 turbine, the second regeneration device, the first regeneration device, the precooling device, and the CO2 compression device.

2. The device system according to claim 1, characterized in that, The gas turbine subsystem includes a compressor, a combustion chamber, and a gas turbine connected in sequence.

3. The device system according to claim 2, characterized in that, The compressor is connected to an air delivery pipeline.

4. The device system according to claim 2, characterized in that, The compressor is an axial flow type.

5. The device system according to claim 2, characterized in that, The combustion chamber is connected to the gas delivery pipeline.

6. The device system according to claim 1, characterized in that, The CO2 compression device includes a centrifugal CO2 compression device.

7. The device system according to claim 1, characterized in that, The first heat exchange device includes any one or a combination of at least two of shell-and-tube heat exchangers, plate heat exchangers, or plate-fin heat exchangers.

8. The device system according to claim 1, characterized in that, The second heat exchange device includes any one or a combination of at least two of shell-and-tube heat exchangers, plate heat exchangers, or plate-fin heat exchangers.

9. The device system according to claim 1, characterized in that, The third heat exchange device includes any one or a combination of at least two of the following: shell-and-tube heat exchangers, plate heat exchangers, or plate-fin heat exchangers.

10. A method for operating a gas turbine coupled with a carbon dioxide Rankine cycle device system as described in any one of claims 1 to 9, characterized in that, The operating method includes: Air supplied by the air supply pipeline enters the combustion chamber via a compressor, where it is burned with gas supplied by the gas supply pipeline. The resulting flue gas enters the gas turbine to perform work. The flue gas discharged from the gas turbine passes through the first heat exchanger, the second heat exchanger, and the third heat exchanger in sequence to exchange heat with CO2 before being discharged into the atmosphere. After being pressurized by the CO2 compression unit, the CO2 enters the first intermediate cooling unit and is cooled into a liquid phase. It then sequentially enters the first CO2 conveying unit, the second intermediate cooling unit, and the second CO2 conveying unit. It is then split into two streams, one entering the third heat exchange unit and the other the first regenerating unit for heat exchange, before converging into the first pipeline. It is then split into two streams again, one entering the second heat exchange unit and the other the second regenerating unit for heat exchange, before converging into the second pipeline. Finally, it splits into two streams once more: one enters the first heat exchange unit for heat exchange, becoming the first CO2; the other enters the first supercritical CO2 turbine to perform work, becoming the second CO2. After the first CO2 enters the second supercritical CO2 turbine to do work, it enters the second regenerator and the first regenerator in sequence for heat exchange, and then enters the CO2 compression unit through the precooling unit; the second CO2 enters the first regenerator for heat exchange, and then enters the CO2 compression unit through the precooling unit, thus completing the Rankine cycle of carbon dioxide.

11. The operating method according to claim 10, characterized in that, The compressor has a pressure ratio of 20 to 45.

12. The operating method according to claim 10, characterized in that, The fuel gas includes hydrogen and natural gas.

13. The operating method according to claim 12, characterized in that, The volume percentage of hydrogen in the gas is 5-100%.

14. The operating method according to claim 10, characterized in that, The temperature of the flue gas produced in the combustion chamber is 1600~1800℃.

15. The operating method according to claim 10, characterized in that, The pressure of the flue gas discharged from the gas turbine is ≥1.03 bar.

16. The operating method according to claim 10, characterized in that, The temperature of the flue gas discharged from the gas turbine is ≥600℃.

17. The operating method according to claim 10, characterized in that, The pressure of CO2 at the outlet of the first CO2 conveying device is 10~25MPa.

18. The operating method according to claim 10, characterized in that, The outlet pressure of CO2 in the second CO2 conveying device is 25~36MPa.

19. The operating method according to claim 10, characterized in that, The CO2 flow rate at the inlet of the first supercritical CO2 turbine is 380~415 kg / s.

20. The operating method according to claim 10, characterized in that, The temperature of CO2 at the inlet of the second supercritical CO2 turbine is 550~610℃.

21. The operating method according to claim 10, characterized in that, The pressure of CO2 at the outlet of the second supercritical CO2 turbine is 4.5~7.3 MPa.

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