Zero-emission marine sofc / gt / sc02 hybrid power system

Abstract

The application discloses a zero-carbon emission ship SOFC / GT / SCO2 hybrid power system, which comprises an air separation oxygen production subsystem, an SOFC / GT hybrid power subsystem, an SCO2 circulation subsystem and a carbon capture subsystem, wherein the air separation oxygen production subsystem combines membrane separation and low-temperature distillation two air separation processes, and meanwhile, the cold energy of LNG and air separation products is fully utilized to liquefy low-temperature distillation raw gas; the SOFC / GT hybrid power subsystem adopts cathode recirculation to realize SOFC temperature control operation, and utilizes cathode recirculation gas to drive a first SCO2 circulation subsystem and utilizes tail gas waste heat to drive a second SCO2 circulation subsystem; in addition, a reforming chamber is combined with a post-combustion chamber, and meanwhile, post-combustion chamber temperature control and reforming chamber efficient reaction are realized; low-temperature carbon capture is adopted to separate water and high-purity CO2 through step-by-step liquefaction. The system has high energy efficiency, and meanwhile, zero-carbon emission of the system is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to energy power equipment, in particular to a zero-carbon emission ship SOFC / GT / SCO2 hybrid power system. BACKGROUND

[0002] LNG-powered ships gradually become the mainstream of green shipping due to their high-efficiency emission reduction advantages. With the increasingly stringent emission regulations and the strong pursuit of "zero-carbon" ships, how to further increase efficiency and reduce emissions has become a research hotspot. At present, LNG-powered ships mostly use dual-fuel engines, which cannot truly achieve zero-carbon emission.

[0003] Solid oxide fuel cell (SOFC) is a device that can directly convert the chemical energy of hydrogen and other fuels into electrical energy. It can be combined with gas turbines, Rankine cycles, etc. to improve the energy utilization efficiency of the system. Although combining SOFC with other power systems can achieve efficiency far exceeding that of traditional internal combustion engines, natural gas itself contains carbon, so additional carbon capture devices need to be added after the power device to achieve zero-carbon emission.

[0004] CN116006361A discloses a LNG-powered ship carbon emission reduction system and method using SOFC. On the basis of the LNG fuel supply system, the SOFC fuel cell cathode reaction gas and anode reaction gas are isolated from each other, the nitrogen gas not participating in the reaction is excluded, and the generated carbon oxides are concentrated and treated, greatly reducing the energy consumption of separation, collection and liquefaction of CO2. However, in this carbon emission reduction system, neither the LNG cold energy nor the SOFC tail gas heat energy can be fully utilized, and the system energy efficiency is low. In addition, only part of the CO2 can be liquefied, and zero-carbon emission cannot be achieved. SUMMARY

[0005] The purpose of the present application is to provide a ship SOFC / GT / SCO2 hybrid power system with high energy efficiency and zero-carbon emission.

[0006] Technical scheme: The zero-carbon emission ship SOFC / GT / SCO2 hybrid power system provided by the present application comprises:

[0007] An air separation oxygen production subsystem is used for low-temperature air separation with LNG and air separation products as cold sources, and the air separation products include high-purity liquid oxygen and nitrogen;

[0008] The SOFC / GT hybrid power subsystem comprises a SOFC and a second turbine, LNG gas is fed into the SOFC anode, oxygen-rich gas is fed into the SOFC cathode, the SOFC anode outlet gas is fed into the afterburning chamber, part of the cathode outlet gas is fed into the afterburning chamber, and the other part is used as cathode recirculation gas; the high-temperature and high-pressure gas combusted in the afterburning chamber is used to drive the second turbine to form SOFC tail gas; and the SOFC tail gas is used to heat the LNG gas fed into the SOFC anode.

[0009] The carbon capture subsystem is arranged at the end of the SOFC tail gas passage, used to separate H2O in the SOFC tail gas, and further used to liquefy CO2 in the tail gas by using the cold energy of the LNG and the air separation product; and high-purity liquid oxygen and LNG are formed after passing through the carbon capture subsystem, and are used to supply oxygen-rich gas and LNG gas to the SOFC respectively; and

[0010] The first SCO2 cycle subsystem is driven by the cathode recirculation gas, and the cathode recirculation gas discharged from the first SCO2 cycle subsystem is mixed with the oxygen-rich gas fed into the SOFC cathode.

[0011] Further, the SOFC / GT hybrid power subsystem further comprises a water pump, an eighth heat exchanger, a fourth compressor, and a second compressor, a third heat exchanger, the fourth heat exchanger, a fifth heat exchanger and a reforming chamber connected in sequence; the LNG gas formed after passing through the carbon capture subsystem is compressed by the second compressor, heated by the third heat exchanger, mixed with water vapor pressurized by the water pump and heated by the eighth heat exchanger, and then heated by the fourth heat exchanger and the fifth heat exchanger in sequence to form hydrogen-rich reforming gas; the hydrogen-rich reforming gas is fed into the fourth heat exchanger as a heat source, and then fed into the SOFC anode; the SOFC tail gas is sequentially passed through the fifth heat exchanger, the third heat exchanger and the eighth heat exchanger as a heat source; the oxygen-rich gas formed after passing through the carbon capture subsystem is compressed by the fourth compressor, mixed with the cathode recirculation gas discharged from the first SCO2 cycle subsystem, and then fed into the SOFC cathode.

[0012] Further, the reforming chamber is arranged inside the afterburning chamber, and the afterburning chamber supplies heat required for the operation of the reforming chamber.

[0013] The present technical solution combines the afterburning chamber and the reforming chamber, uses the highly endothermic methane steam reforming reaction inside the reforming chamber to reduce the operating temperature of the afterburning chamber during oxygen-rich combustion, and simultaneously realizes the control of the afterburning chamber temperature and the improvement of the hydrogen conversion efficiency of the reforming chamber.

[0014] Further, the ship SOFC / GT / SCO2 hybrid power system further comprises a second SCO2 cycle subsystem arranged before the carbon capture subsystem and driven by the SOFC tail gas.

[0015] Further, the second SCO2 cycle subsystem comprises a third turbine, a sixth heat exchanger, a first cooler, a third compressor and a seventh heat exchanger; the SOFC tail gas passes through the third heat exchanger, the seventh heat exchanger and the eighth heat exchanger in sequence; the SOFC tail gas heats the circulating medium in the seventh heat exchanger, and then the circulating medium expands to do work in the third turbine; the expanded circulating medium is cooled in the sixth heat exchanger and further cooled in the first cooler; the further cooled circulating medium is compressed in the third compressor and heated in the sixth heat exchanger, and then returns to the seventh heat exchanger to complete a cycle.

[0016] Further, the air separation oxygen production subsystem comprises a first turbine, a second rectification tower, and an air separation membrane, a vacuum pump, a first compressor, a first heat exchanger, a pump turbine and a first rectification tower connected in sequence; air is purified into oxygen-rich air by the air separation membrane, the vacuum pump is used to provide gas diffusion driving force, and then compressed by the first compressor, cooled and liquefied in the first heat exchanger, decompressed by the pump turbine and then enters the first rectification tower for preliminary rectification; the separated high-purity nitrogen is used to do work in the first turbine, and the separated oxygen-rich liquid is introduced into the second rectification tower for further rectification; the high-purity nitrogen separated from the second rectification tower is combined with the high-purity nitrogen after work, and the high-purity liquid oxygen separated from the second rectification tower, the combined high-purity nitrogen and the LNG are used as the cold source liquid of the first heat exchanger to liquefy the oxygen-rich air.

[0017] The air separation oxygen production subsystem combines the membrane separation and low-temperature distillation air separation processes, and fully utilizes the cold energy of the LNG and the air separation products to liquefy the low-temperature distillation raw gas.

[0018] Further, the first SCO2 cycle subsystem comprises a ninth heat exchanger, a fourth turbine, a tenth heat exchanger, a second cooler and a fifth compressor; the cathode recirculation gas heats the circulating medium in the ninth heat exchanger, and then the circulating medium expands to do work in the fourth turbine; the expanded circulating medium is cooled in the tenth heat exchanger and further cooled in the second cooler; the further cooled circulating medium is compressed in the fifth compressor and heated in the tenth heat exchanger, and then returns to the ninth heat exchanger to complete a cycle.

[0019] Further, the carbon capture subsystem comprises a second heat exchanger, a third cooler, a water vapor separation tower and a sixth compressor; the SOFC tail gas is cooled in the third cooler, and then H2O and uncondensed gas are separated in the water vapor separation tower; the uncondensed gas is compressed by the sixth compressor and then condensed into high-purity liquid CO2 in the second heat exchanger; the cold source of the second heat exchanger is the LNG and the air separation products discharged from the air separation oxygen production subsystem.

[0020] Further, the cooler uses seawater as the cold source.

[0021] Further, the compressors in the SCO2 cycle subsystem and the carbon capture subsystem adopt a multi-stage compression intercooling process.

[0022] Advantages: Compared with the prior art, the present application has the following remarkable advantages:

[0023] (1) The cold energy of LNG and air separation products is utilized simultaneously, thereby reducing the energy consumption of air separation;

[0024] (2) The SCO2 cycle subsystem is adopted to replace the common water vapor power cycle to recover the heat of tail gas and cathode circulating gas, thereby reducing the volume of equipment and improving the efficiency of circulation; the cathode recirculation process is adopted in the first SCO2 cycle subsystem SOFC, thereby realizing the control of SOFC operating temperature under the condition of low cathode inlet gas flow, and the high-temperature gas of the cathode is used to drive the first SCO2 cycle subsystem, so that the temperature control of SOFC and the effective utilization of system energy are realized simultaneously.

[0025] (3) The air separation oxygen-enriched combustion technology is adopted, thereby greatly reducing the nitrogen content in tail gas; the low-temperature carbon capture method is adopted, thereby realizing the step-by-step liquefaction and separation of water and high-purity CO2, and realizing the cascade utilization of cold energy of LNG and air separation products, and realizing zero carbon emission of the system.

[0026] In the present application, the LNG cold energy and SOFC tail gas waste heat are effectively utilized, the system has high energy efficiency; at the same time, zero carbon emission of the system can be realized; the present application provides a feasible solution for the efficient and zero-carbon development of LNG power ships. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a structural schematic diagram of a zero-carbon emission ship SOFC / GT / SCO2 hybrid power system provided by the embodiment of the present application. DETAILED DESCRIPTION

[0028] The present application will be further described below with reference to the drawings.

[0029] As Figure 1 shown is a structural schematic diagram of a zero-carbon emission ship SOFC / GT / SCO2 hybrid power system provided by the embodiment of the present application, the ship SOFC / GT / SCO2 hybrid power system comprises the following components:

[0030] 1, air separation membrane; 2, vacuum pump; 3, first compressor; 4, first heat exchanger; 5, second heat exchanger; 6, pump turbine; 7, first rectifying tower; 8, first turbine; 9, second rectifying tower; 10, first mixer; 11, second compressor; 12, third heat exchanger; 13, second mixer; 14, fourth heat exchanger; 15, fifth heat exchanger; 16, reforming chamber; 17, SOFC; 18, separator; 19, afterburning chamber; 20, second turbine; 21, third turbine; 22, sixth heat exchanger; 23, first cooler; 24, third compressor; 25, seventh heat exchanger; 26, water pump; 27, eighth heat exchanger; 28, fourth compressor; 29, third mixer; 30, ninth heat exchanger; 31, fourth turbine; 32, tenth heat exchanger; 33, second cooler; 34, fifth compressor; 35, third cooler; 36, water vapor separation tower; 37, sixth compressor.

[0031] The structure and working principle of the ship SOFC / GT / SCO2 hybrid power system are specifically introduced below.

[0032] The zero-carbon emission ship SOFC / GT / SCO2 hybrid power system provided by the embodiment of the application comprises an air separation oxygen production subsystem, an SOFC / GT hybrid power subsystem, an SCO2 cycle subsystem, and a carbon capture subsystem, wherein the SCO2 cycle subsystem comprises a first SCO2 cycle subsystem and a second SCO2 cycle subsystem.

[0033] The air separation oxygen production subsystem comprises an air separation membrane 1, a vacuum pump 2, a first compressor 3, a first heat exchanger 4, a pump turbine 6, a first rectifying tower 7, a first turbine 8, a second rectifying tower 9, and a first mixer 10.

[0034] The air separation membrane 1, the vacuum pump 2, the first compressor 3, the first heat exchanger 4, the pump turbine 6, and the first rectifying tower 7 are sequentially connected, the top end of the first rectifying tower 7 is connected with the first turbine 8, the bottom end is connected with the second rectifying tower 9, and the bottom end of the second rectifying tower 9 is connected with the first heat exchanger 4. The front end of the first mixer 10 is connected with the outlet of the first turbine 8 and the top of the second rectifying tower 9 respectively, and the rear end is connected with the first heat exchanger 4.

[0035] The SOFC / GT hybrid power subsystem comprises a second compressor 11, a third heat exchanger 12, a second mixer 13, a fourth heat exchanger 14, a fifth heat exchanger 15, a reforming chamber 16, an SOFC 17, a separator 18, an afterburning chamber 19, a second turbine 20, a water pump 26, an eighth heat exchanger 27, a fourth compressor 28, and a third mixer 29.

[0036] The second compressor 11 is connected with the third heat exchanger 12, the water pump 26 is connected with the eighth heat exchanger 27, and the front end of the second mixer 13 is connected with the third heat exchanger 12 and the eighth heat exchanger 27 respectively. The rear end of the second mixer 13 is connected with the fourth heat exchanger 14, and the fourth heat exchanger 14, the fifth heat exchanger 15 and the reforming chamber 16 are connected in sequence. The outlet of the reforming chamber 16 is connected with the upper inlet of the fourth heat exchanger 14, the anode inlet of the SOFC 17 is connected with the lower outlet of the fourth heat exchanger 14, the cathode inlet of the SOFC 17 is connected with the rear end of the third mixer 29, the anode outlet of the SOFC 17 is connected with the inlet of the afterburning chamber 19, the cathode outlet of the SOFC 17 is connected with the separator 18, and the separator 18 separates the cathode outlet gas into two streams, one of which is introduced into the afterburning chamber 19, and the other is used as the cathode recirculation gas. The outlet of the afterburning chamber 19 is connected with the second turbine 20, the outlet of the second turbine 20 is connected with the upper inlet of the fifth heat exchanger 15, and the lower outlet of the fifth heat exchanger 15 is connected with the upper inlet of the third heat exchanger 12.

[0037] The first SCO2 circulation subsystem includes the ninth heat exchanger 30, the fourth turbine 31, the tenth heat exchanger 32, the second cooler 33 and the fifth compressor 34. The ninth heat exchanger 30 is arranged between the third mixer 29 and the separator 18, the cathode recirculation gas is introduced into the right end inlet of the ninth heat exchanger 30, and the front end of the third mixer 29 is connected with the outlet of the fourth compressor 28 and the left end outlet of the ninth heat exchanger 30 respectively. The fourth turbine 31 is arranged between the ninth heat exchanger 30 and the tenth heat exchanger 32. The inlet of the second cooler 33 is connected with the tenth heat exchanger 32, the inlet of the fifth compressor 34 is connected with the outlet of the second cooler 33, and the outlet of the fifth compressor 34 is connected with the tenth heat exchanger 32.

[0038] The second SCO2 circulation subsystem includes the third turbine 21, the sixth heat exchanger 22, the first cooler 23, the third compressor 24 and the seventh heat exchanger 25. The third heat exchanger 12, the seventh heat exchanger 25 and the eighth heat exchanger 27 are connected in sequence. The third turbine 21 is arranged between the seventh heat exchanger 25 and the sixth heat exchanger 22. The inlet of the first cooler 23 is connected with the sixth heat exchanger 22. The inlet of the third compressor 24 is connected with the outlet of the first cooler 23, and the outlet of the third compressor 24 is connected with the sixth heat exchanger 22.

[0039] The carbon capture subsystem includes the second heat exchanger 5, the third cooler 35, the water vapor separation tower 36 and the sixth compressor 37. The eighth heat exchanger 27, the third cooler 35, the water vapor separation tower 36, the sixth compressor 37 and the second heat exchanger 5 are connected in sequence. The second heat exchanger 5, the second compressor 11 and the third heat exchanger 12 are connected in sequence.

[0040] In the embodiment, the reforming chamber 16 is arranged inside the afterburning chamber 19, and the afterburning chamber 19 supplies the heat required for the operation of the reforming chamber 16.

[0041] The third compressor 24 and the fifth compressor 34 adopt a multi-stage compression intercooling process to reduce the energy consumption of the compressor and improve the power generation efficiency of the cycle.

[0042] The first cooler 23, the second cooler 33 and the third cooler 35 adopt seawater as the cold source, and the seawater temperature is 20℃.

[0043] The sixth heat exchanger 22 and the tenth heat exchanger 32 are regenerators, which can recover the waste heat of the high-temperature gas at the turbine outlet, reduce the energy loss at the corresponding cooler end, and improve the power generation efficiency of the cycle.

[0044] The working principle of the zero-carbon emission ship SOFC / GT / SCO2 hybrid power system provided in the embodiments of the present application is specifically introduced below.

[0045] (I) Air separation and oxygen production subsystem

[0046] The air separation and oxygen production subsystem combines membrane separation and low-temperature distillation air separation processes, and uses the cold energy of LNG and air separation products to liquefy gas.

[0047] Specifically, air is purified by an air separation membrane 1 to contain 40.81% of oxygen-enriched air, a vacuum pump 2 is used to provide gas diffusion driving force, then the oxygen-enriched air is compressed by a first compressor 3 and liquefied by a first heat exchanger 4, and then depressurized by a pump turbine 6 and enters a first rectifying column 7 for preliminary rectification. High-purity nitrogen is separated from the top of the first rectifying column 7, and oxygen-enriched liquid is separated from the bottom of the first rectifying column 7. The oxygen-enriched liquid is introduced into a second rectifying column 9 for further rectification, and high-purity nitrogen is led out from the top of the second rectifying column 9. The high-purity nitrogen is combined with the high-purity nitrogen at the top of the first rectifying column 7 that has done work through the first turbine 8 in a first mixer 10, and high-purity liquid oxygen is led out from the bottom of the second rectifying column 9. The LNG, the high-purity liquid oxygen and the combined high-purity nitrogen are respectively introduced into the first heat exchanger 4 to liquefy the oxygen-enriched air.

[0048] (II) SOFC / GT hybrid power subsystem

[0049] The LNG gasified by the second heat exchanger 5 is compressed by a second compressor 11 to a certain pressure, heated by a third heat exchanger 12, and mixed with water vapor gasified by a water pump 26 and an eighth heat exchanger 27 in a second mixer 13. The mixed gas is heated by a fourth heat exchanger 14 and a fifth heat exchanger 15 in turn, and then sent to a reforming chamber 16. The heat for the operation of the reforming chamber 16 is provided by a post-combustion chamber 19. The hydrogen-rich reforming gas at the outlet of the reforming chamber 16 is cooled by the fourth heat exchanger 14 and introduced into the anode of an SOFC 17.

[0050] The oxygen-enriched gas, which is gasified by the second heat exchanger 5 and compressed by the fourth compressor 28, is mixed with the cathode recirculation gas from the left end outlet of the ninth heat exchanger 30 in the third mixer 29, and then enters the cathode of the SOFC 17. The hydrogen-rich reforming gas reacts with the oxygen-enriched gas in the SOFC 17 to generate electric energy. The gas after the anode reaction of the SOFC 17 directly enters the afterburner 19 for combustion. The gas from the cathode outlet of the SOFC 17 is separated by the separator 18 into two streams. One stream enters the afterburner 19 for combustion, and the other stream drives the first SCO2 circulation subsystem through the ninth heat exchanger 30. The SOFC can adjust the operating temperature by adjusting the cathode recirculation ratio.

[0051] The high-temperature and high-pressure exhaust gas after combustion in the afterburner 19 drives the second turbine 20. The gas after work is sequentially passed through the fifth heat exchanger 15, the third heat exchanger 12, the seventh heat exchanger 25, and the eighth heat exchanger 27. The seventh heat exchanger 25 drives the second SCO2 circulation subsystem using the waste heat of the exhaust gas.

[0052] (Three) SCO2 Circulation Subsystem

[0053] The first SCO2 circulation subsystem is driven by the cathode recirculation gas. The ninth heat exchanger 30 heats the circulating working medium, which is then expanded to do work at the fourth turbine 31. The expanded working medium gas is cooled by the tenth heat exchanger 32 and further cooled at the second cooler 33. The further cooled gas is compressed at the fifth compressor 34 and heated by the tenth heat exchanger 32, and then returns to the ninth heat exchanger 30 to complete a cycle.

[0054] The second SCO2 circulation subsystem is driven by the waste heat of the SOFC exhaust gas. The circulating working medium is heated at the seventh heat exchanger 25 and expanded to do work at the third turbine 21. The expanded working medium gas is cooled by the sixth heat exchanger 22 and further cooled at the first cooler 23. The further cooled gas is compressed at the third compressor 24 and heated by the sixth heat exchanger 22, and then returns to the seventh heat exchanger 25 to complete a cycle.

[0055] (Four) Carbon Capture Subsystem

[0056] The carbon capture system uses a low-temperature method to capture liquefied CO2, realizing simultaneous carbon capture and carbon storage.

[0057] In the carbon capture subsystem, the exhaust gas is cooled to 25°C by the third cooler 35, at which time most of the water vapor condenses and is separated out. Then, the uncondensed gas is compressed by the sixth compressor 37 and then enters the second heat exchanger 5 to be condensed into liquid high-purity CO2. The second heat exchanger 5 uses the remaining cold energy after air separation of the air separation product and LNG to liquefy CO2, achieving full utilization of the cold energy of the system.

[0058] The following gives a specific example to further introduce the feasibility of the present application.

[0059] The system initial conditions are shown in Table 1, and the system simulation results are shown in Table 2.

[0060] Table 1 System initial conditions

[0061]

[0062] Table 2 System simulation results

[0063]

[0064] From Table 2, under the system initial conditions of Table 1, the present application can achieve a system net power generation efficiency of 55.92% and a system net power generation of 6730 kW, and the present application can achieve a CO2 capture rate of 15 mol / s, achieving zero carbon emission operation of the system. If calculated according to 6000 hours of system operation per year, 22963 tons of CO2 emission can be reduced per year.

[0065] In summary, the present application achieves efficient zero emission operation of a ship, and provides a feasible scheme for green and efficient development of a LNG powered ship.

Claims

1. A zero-carbon emission marine SOFC / GT / SCO2 hybrid power system, characterized in that, include: The air separation oxygen generation subsystem is used to perform cryogenic air separation using LNG and air separation products as a cold source. The air separation products include high-purity liquid oxygen and nitrogen. The SOFC / GT hybrid subsystem includes an SOFC (17) and a second turbine (20). LNG gas is fed into the anode of the SOFC (17), oxygen-enriched gas is fed into the cathode of the SOFC (17), and the outlet gas of the SOFC (17) anode is fed into the afterburner (19). Part of the outlet gas of the cathode is fed into the afterburner (19), and the other part is used as cathode recirculation gas. The high-temperature and high-pressure gas after combustion in the afterburner (19) is used to form SOFC exhaust gas after the second turbine (20) does work. The SOFC exhaust gas is used to heat the LNG gas fed into the anode of the SOFC (17). A carbon capture subsystem, located at the end of the SOFC tail gas passage, is used to separate H2O from the SOFC tail gas and further utilize the cooling energy of LNG and air separation products to liquefy CO2 in the tail gas. High-purity liquid oxygen and LNG, after passing through the carbon capture subsystem, respectively form oxygen-enriched gas and LNG gas supplied to the SOFC (17); and... The first SCO2 circulation subsystem is driven by cathode recirculation gas. The cathode recirculation gas discharged from the first SCO2 circulation subsystem is mixed with the oxygen-enriched gas fed into the cathode of SOFC (17). SOFC (17) adjusts the SOFC operating temperature by adjusting the cathode recirculation ratio. The air separation oxygen generation subsystem includes a first turbine (8), a second distillation column (9), and air separation membrane (1), vacuum pump (2), first compressor (3), first heat exchanger (4), pump turbine (6), and first distillation column (7) connected in sequence. Air is purified into oxygen-enriched air by the air separation membrane (1), the vacuum pump (2) is used to provide gas diffusion driving force, and then compressed by the first compressor (3) and liquefied by cooling in the first heat exchanger (4). After being depressurized by the pump turbine (6), it enters the first distillation column (7) for preliminary distillation. The separated high-purity nitrogen is used to do work in the first turbine (8), and the separated oxygen-enriched liquid is introduced into the second distillation column (9) for further distillation. The high-purity nitrogen separated from the second distillation column (9) is combined with the high-purity nitrogen after doing work. The high-purity liquid oxygen separated from the second distillation column (9), the combined high-purity nitrogen, and LNG are used as the cold source of the first heat exchanger (4) to liquefy the oxygen-enriched air.

2. The marine SOFC / GT / SCO2 hybrid power system according to claim 1, characterized in that, The SOFC / GT hybrid subsystem also includes a water pump (26), an eighth heat exchanger (27), a fourth compressor (28), and a second compressor (11), a third heat exchanger (12), a fourth heat exchanger (14), a fifth heat exchanger (15), and a reforming chamber (16) connected in sequence. The LNG gas formed after passing through the carbon capture subsystem is compressed by the second compressor (11), heated by the third heat exchanger (12), and then mixed with water vapor formed by pressurization by the water pump (26) and heating by the eighth heat exchanger (27). The mixed gas is then transferred to the fourth heat exchanger (28) for further processing. After being heated, the heat exchangers (14) and the fifth heat exchanger (15) are sent to the reforming chamber (16) to generate hydrogen-rich reformed gas. The hydrogen-rich reformed gas is sent to the fourth heat exchanger (14) as a heat source and then sent to the SOFC (17) anode. The SOFC tail gas is used as a heat source and passes through the fifth heat exchanger (15), the third heat exchanger (12) and the eighth heat exchanger (27) in sequence. The oxygen-rich gas formed after passing through the carbon capture subsystem is compressed by the fourth compressor (28) and mixed with the cathode recirculated gas discharged from the first SCO2 cycle subsystem and sent to the SOFC (17) cathode.

3. The marine SOFC / GT / SCO2 hybrid power system according to claim 2, characterized in that, The reforming chamber (16) is located inside the afterburner (19), and the afterburner (19) supplies the heat required for the operation of the reforming chamber (16).

4. The marine SOFC / GT / SCO2 hybrid power system according to claim 2, characterized in that, It also includes a second SCO2 cycle subsystem, located before the carbon capture subsystem, driven by SOFC exhaust gas.

5. The marine SOFC / GT / SCO2 hybrid power system according to claim 4, characterized in that, The second SCO2 cycle subsystem includes a third turbine (21), a sixth heat exchanger (22), a first cooler (23), a third compressor (24), and a seventh heat exchanger (25). The SOFC exhaust gas passes through the third heat exchanger (12), the seventh heat exchanger (25), and the eighth heat exchanger (27) in sequence. The SOFC exhaust gas heats the working fluid in the seventh heat exchanger (25), and then the working fluid expands and does work in the third turbine (21). The expanded working fluid is cooled by the sixth heat exchanger (22) and further cooled by the first cooler (23). The further cooled working fluid is compressed in the third compressor (24) and heated by the sixth heat exchanger (22), and then returns to the seventh heat exchanger (25) to complete one cycle.

6. The marine SOFC / GT / SCO2 hybrid power system according to claim 1, characterized in that, The first SCO2 cycle subsystem includes a ninth heat exchanger (30), a fourth turbine (31), a tenth heat exchanger (32), a second cooler (33), and a fifth compressor (34). The cathode recirculated gas heats the working fluid in the ninth heat exchanger (30), and then the working fluid expands and does work in the fourth turbine (31). The expanded working fluid is cooled by the tenth heat exchanger (32) and further cooled by the second cooler (33). The further cooled working fluid is compressed in the fifth compressor (34), heated by the tenth heat exchanger (32), and then returns to the ninth heat exchanger (30) to complete a cycle.

7. The marine SOFC / GT / SCO2 hybrid power system according to claim 1, characterized in that, The carbon capture subsystem includes a second heat exchanger (5), a third cooler (35), a water vapor separator (36), and a sixth compressor (37). After the SOFC tail gas is cooled by the third cooler (35), H2O and uncondensed gas are separated in the water vapor separator (36). The uncondensed gas is compressed by the sixth compressor (37) and then condensed into high-purity liquid CO2 in the second heat exchanger (5). The cold source of the second heat exchanger (5) is the LNG and air separation products discharged from the air separation oxygen production subsystem.

8. The marine SOFC / GT / SCO2 hybrid power system according to claim 5, 6 or 7, characterized in that, The cooler uses seawater as its cooling source.

9. The marine SOFC / GT / SCO2 hybrid power system according to claim 5, 6 or 7, characterized in that, The compressors in the SCO2 cycle subsystem and carbon capture subsystem employ a multi-stage compression interstage cooling process.

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