LNG transport ship power generation system and LNG transport ship

Abstract

The invention provides an LNG transport ship power generation system and an LNG transport ship, the power generation system comprises a fuel cell power generation assembly, and the fuel cell power generation assembly comprises a methane reforming reactor, a first heat exchanger, a second heat exchanger, a fuel cell, a post-combustion module, a converter and a discharge end. Liquefied natural gas (LNG) liquid cargo tank flash steam is conveyed to the methane reforming reactor, and a reforming product enters a fuel cell anode through the first side of the first heat exchanger. Air enters the cathode through the first side of the second heat exchanger. And the electric energy output end of the fuel cell is connected with the converter and outputs the electric energy. The first heat exchanger second-side outlet is connected with the second heat exchanger second-side inlet, and the second heat exchanger second-side outlet is connected with the discharge end. Tail gas of the rear combustion module is connected with a second side inlet of the first heat exchanger, a second side inlet of the second heat exchanger and a discharge end through three branches, and each branch is provided with an on-off valve. The LNG flash steam serves as fuel, power is generated through the fuel cell to supply power to the ship, carbon emission is reduced, reliquefaction is abandoned, and reasonable utilization of waste heat is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of fuel cell power generation, and in particular, to an LNG carrier power generation system and an LNG carrier that use fuel cells for power generation. Background Art

[0002] Boil Off Gas (BOG) refers to the gas generated by the vaporization of liquid cargo in a liquid cargo carrier due to environmental heat exchange or pressure changes. Taking an LNG (Liquefied Natural Gas) carrier as an example, its BOG is mainly formed by the evaporation of LNG due to heat, and its main component is methane (CH 4 )). It will not only lead to a reduction in the LNG cargo volume, but also increase the pressure in the liquid cargo tank. If these evaporation gases cannot be effectively treated, the excessive pressure may damage the structure of the liquid cargo tank and even cause safety problems.

[0003] Traditionally, in order to prevent the pressure in the LNG liquid cargo tank from being too high and to minimize the waste of LNG boil-off gas as much as possible, the BOG is usually re-liquefied and returned to the liquid cargo tank. Existing re-liquefaction systems usually include equipment such as multi-stage compressors, expanders, heat exchangers, and condensers. Their complex process flow results in a large volume of equipment, making it difficult to efficiently arrange them in the limited space of a ship. At the same time, the re-liquefaction system requires a large amount of electricity to maintain low-temperature conditions to prevent LNG evaporation, and this electricity often comes from burning more fuel, forming a vicious cycle. In addition, some of the residual BOG that is not completely liquefied or the BOG that exceeds the re-liquefaction processing capacity during system operation needs to be discharged by flare combustion, which not only causes energy waste but also further increases the emissions of greenhouse gases, which is extremely unfavorable to environmental protection requirements.

[0004] In addition, with the increasingly strict requirements of international relevant organizations for ship carbon emissions and energy efficiency, LNG carriers face multiple challenges: on the one hand, it is necessary to optimize the space occupation of the BOG re-liquefaction treatment system and the energy efficiency of the ship; on the other hand, the traditional ship propulsion system still mainly relies on fossil fuel internal combustion engines to provide power, and its carbon emission level is difficult to meet the sustainable development goals of the industry's energy conservation and emission reduction. Summary of the Invention

[0005] The purpose of the present application is to provide an LNG carrier power generation system and an LNG carrier that can use LNG boil-off gas as fuel and generate electricity through a solid oxide fuel cell to supply ship power, significantly reduce carbon emissions, can streamline the re-liquefaction system, avoid the energy consumption during the re-liquefaction process, and can also achieve the efficient and reasonable utilization of the waste heat of the exhaust gas after power generation.

[0006] In a first aspect, a power generation system for an LNG carrier is provided, which includes an LNG cargo tank and a fuel cell power generation component. The fuel cell power generation component includes a methane reforming reactor, a first heat exchanger, a second heat exchanger, a fuel cell, a post-combustion module, a converter, and an emission end; both the first heat exchanger and the second heat exchanger include a first side and a second side. The flash gas in the LNG cargo tank is transported to the methane reforming reactor. The outlet of the methane reforming reactor is connected to the inlet of the first side of the first heat exchanger, and the outlet of the first side of the first heat exchanger is connected to the anode inlet of the fuel cell. Air is transported to the inlet of the first side of the second heat exchanger, and the outlet of the first side of the second heat exchanger is connected to the cathode inlet of the fuel cell. The anode and cathode outlets of the fuel cell are connected to the post-combustion module, and the power output end of the fuel cell is connected to the converter and outputs power outward.

[0007] The outlet of the second side of the first heat exchanger is connected to the inlet of the second side of the second heat exchanger, and the outlet of the second side of the second heat exchanger is connected to the emission end. The emission port of the post-combustion module is connected to the inlet of the second side of the first heat exchanger, the inlet of the second side of the second heat exchanger, and the emission end through three branch roads, and a on-off valve is arranged on each branch road.

[0008] In an implementable solution, by comparing the temperatures at the emission port of the post-combustion module, the inlet of the first side of the first heat exchanger, and the inlet of the first side of the second heat exchanger, the opening or closing of the on-off valve is controlled.

[0009] In an implementable solution, the three branch roads connecting the emission port of the post-combustion module to the inlet of the second side of the first heat exchanger, the inlet of the second side of the second heat exchanger, and the emission end are respectively the first branch road, the second branch road, and the third branch road; a first on-off valve is arranged on the first branch road, a second on-off valve is arranged on the second branch road, and a third on-off valve is arranged on the third branch road; a control module is further included, which is communicatively connected to the first on-off valve, the second on-off valve, and the third on-off valve and controls the opening or closing of each valve.

[0010] In an implementable solution, a first temperature sensor is arranged at the emission port of the post-combustion module, a second temperature sensor is arranged at the inlet of the first side of the first heat exchanger, and a third temperature sensor is arranged at the inlet of the first side of the second heat exchanger; the first temperature sensor, the second temperature sensor, and the third temperature sensor are communicatively connected to the control module.

[0011] In an implementable solution, the steps for the control module to control the opening or closing of the first on-off valve, the second on-off valve, and the third on-off valve include:

[0012] The control module obtains the temperature values of the first temperature sensor, the second temperature sensor, and the third temperature sensor, which are respectively , , ;

[0013] The control module performs operations on , , Compare the sizes and send corresponding control signals;

[0014] If , the control module controls the first on-off valve to remain open and controls the second on-off valve and the third on-off valve to remain closed;

[0015] If and , the control module controls the second on-off valve to remain open and controls the first on-off valve and the third on-off valve to remain closed;

[0016] If and , the control module controls the third on-off valve to remain open and controls the first on-off valve and the second on-off valve to remain closed.

[0017] In an implementable solution, the post-combustion module includes a separator and a post-combustion chamber; the anode outlet of the fuel cell is connected to the inlet of the separator, and the cathode outlet of the fuel cell is connected to the post-combustion chamber; the separator includes a first outlet and a second outlet, and the first outlet of the separator is connected to the methane reforming reactor, and the second outlet of the separator is connected to the post-combustion chamber.

[0018] In an implementable solution, proportional valves are provided at both the first outlet and the second outlet of the separator, and the proportional valves are used to adjust the gas outlet ratio of the first outlet and the second outlet of the separator.

[0019] In an implementable solution, the LNG carrier power generation system further includes a buffer tank, a flow detector, and a buffer controller; the buffer tank is upstream of the methane reforming reactor and is connected to the pipeline in parallel. A buffer inlet valve is installed at the inlet of the buffer tank, a buffer outlet valve is installed at the outlet of the buffer tank, and a through valve is installed in the pipeline parallel to the buffer tank; the flow detector is arranged on the outlet side of the LNG cargo tank, and the buffer controller is communicatively connected to the flow detector, the buffer inlet valve, the buffer outlet valve, and the through valve.

[0020] In an implementable solution, a flow desired threshold value is pre-stored in the buffer controller ; the steps for the buffer controller to control the opening or closing of the buffer inlet valve, the buffer outlet valve, and the through valve include:

[0021] The buffer controller obtains the real-time flow value as through the flow detector;

[0022] The buffer controller judges the size of the real-time flow value and the flow desired threshold value ;

[0023] If , the buffer controller controls the buffer inlet valve and the buffer outlet valve to remain closed, and controls the direct-through valve to remain open;

[0024] If , the buffer controller controls the buffer inlet valve and the buffer outlet valve to remain open, and controls the direct-through valve to remain open.

[0025] In an implementable solution, the converter power output terminal includes a first interface and a second interface. The first interface is connected to an electrical load device, and the second interface is connected to an energy storage device.

[0026] In an implementable solution, the LNG carrier power generation system includes a waste heat utilization module, which includes a first side and a second side. The discharge end is discharged through the first side pipeline of the waste heat utilization module, and normal temperature water is introduced into the second side of the waste heat utilization module.

[0027] In an implementable solution, the LNG carrier power generation system further includes a box structure and a temperature control component. At least the fuel cell is in the box structure; the temperature control component includes an electric heating rod placed in the box structure and a thermocouple placed in the fuel cell. The temperature control component further includes a temperature master controller, and the temperature master controller determines the temperature in the fuel cell through the thermocouple and controls the energization or de-energization of the electric heating rod.

[0028] In a second aspect, an LNG carrier is further provided, which includes a hull and the aforementioned LNG carrier power generation system; the hull includes an engine room and a number of LNG cargo tanks, and the LNG carrier power generation system is arranged at the engine room.

[0029] Compared with the prior art, the beneficial effects of the present application at least include: the LNG carrier power generation system of the present application can consume LNG flash gas as fuel for power generation, and there is no need to consume electricity to maintain low temperature to prevent the evaporation of re-liquefied LNG. Therefore, the re-liquefaction system can be discarded, the fuel management system on the ship can be simplified, the energy consumption can be greatly reduced, and at the same time, the ship structure can be optimized, the space utilization rate of the ship can be improved, and it is helpful to increase the loading capacity of the LNG carrier. At the same time, for the LNG power generation system of the present application, the fuel cell and the reaction products after post-combustion hardly produce any harmful emissions, and almost no other pollutants are released except carbon dioxide. Although CO 2 is still a greenhouse gas, compared with traditional internal combustion engines or re-liquefaction equipment, the carbon footprint of the fuel cell power generation of the power generation system of the present application is much smaller, so the emission of greenhouse gases can be reduced. Further, since the amount of flash gas generated in the LNG cargo tank is large enough, the LNG carrier power generation system of the present application can be used as the navigation and full-ship power source of the LNG carrier, thereby optimizing the internal combustion engine configuration. On the one hand, the space occupancy rate is optimized, and on the other hand, it provides assistance for realizing the low-carbon emission of the ship.

[0030] Meanwhile, in the power generation system of the LNG carrier of the present application, the exhaust gas emitted by the post-combustion module is respectively connected to the first heat exchanger, the second heat exchanger and the discharge end through three branches provided with on-off valves, so as to selectively use the high-temperature exhaust gas for preheating air, preheating methane fuel or directly discharging according to needs, thereby more reasonably and effectively utilizing the heat of the combustion exhaust gas of the post-combustion module, realizing temperature complementarity and selective cascade utilization of energy, improving the cascade utilization rate of the system waste heat, and avoiding the adverse effects brought by unreasonable waste heat utilization to the reaction of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a schematic diagram of the composition of an LNG carrier power generation system shown in an embodiment of the present application.

[0033] Figure 2 It is a schematic diagram of the composition of an LNG carrier power generation system with an automatic exhaust gas path selection function shown in an embodiment of the present application.

[0034] Figure 3 It is a schematic diagram of the composition of an LNG carrier power generation system with a buffer tank shown in an embodiment of the present application.

[0035] Figure 4 It is a schematic diagram of the composition of an LNG carrier power generation system with an energy storage device shown in an embodiment of the present application.

[0036] Figure 5 It is a schematic diagram of the composition of an LNG carrier shown in an embodiment of the present application.

[0037] Figure 6 It is a schematic diagram of the composition of another LNG carrier shown in an embodiment of the present application.

[0038] In the figure: 1. Fuel cell power generation module; 11. Methane reforming reactor; 12. First heat exchanger; 13. Second heat exchanger; 14. Fuel cell; 15. Post-combustion module; 151. Separator; 152. Post-combustion chamber; 16. Converter; 17. Discharge end; 18. Control module; A1. First branch; A2. Second branch; A3. Third branch; P1. First on-off valve; P2. Second on-off valve; P3. Third on-off valve; H1. First temperature sensor; H2. Second temperature sensor; H3. Third temperature sensor; 2. Buffer tank; 21. Flow detector; 22. Buffer controller; M1. Buffer inlet valve; M2. Buffer outlet valve; M3. Straight-through valve; 3. Energy storage device; 4. Temperature control module; 5. Waste heat utilization module; 100. LNG cargo tank; 200. Engine room. Detailed implementation manners

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. The components of the embodiments of the present application usually described and illustrated in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application claimed, but merely represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0041] One of the objectives of the inventors of the present application in proposing the technical solutions of the present application is, on the one hand, to improve the utilization rate of LNG flash gas and to expect to abandon the re-liquefaction system to optimize the hull structure; on the other hand, it is to achieve further energy conservation and emission reduction.

[0042] Meanwhile, the inventors also found that in the power generation system of a conventional solid oxide fuel cell, the gases that have not fully reacted at the anode and cathode of the fuel cell are transported to the afterburner for combustion treatment. Since the temperature of the exhaust gas discharged from the outlet of the afterburner is quite high, the usual treatment method is to use this part of the exhaust gas to preheat the air entering the fuel cell, and then discharge the exhaust gas after completion of the preheating. However, even after being used to preheat the air, the exhaust gas discharged from the afterburner still retains a relatively high temperature. If directly discharged, it will cause a large amount of heat waste, resulting in low energy utilization rate, which is actually an indirect waste of flash steam. In addition, in some power generation systems, the exhaust gas will be further used to preheat the fuel gas after preheating the air. However, in certain specific situations, the temperature of the exhaust gas discharged from the afterburner may be lower than the temperature of the fuel gas. At this time, if the exhaust gas is allowed to exchange heat with the fuel gas, not only can effective preheating not be achieved, but on the contrary, the temperature of the fuel gas will be reduced, resulting in side effects, thereby reducing the reaction efficiency and adding an additional burden to the reaction process of the fuel cell.

[0043] To solve the foregoing technical problems, as Figure 1 shown, an embodiment of the present application first provides an LNG carrier power generation system, including an LNG liquid cargo tank 100 and a fuel cell power generation assembly 1. The fuel cell power generation assembly 1 includes a methane reforming reactor 11, a first heat exchanger 12, a second heat exchanger 13, a fuel cell 14, an afterburning module 15, a converter 16, and an emission end 17.

[0044] Both the first heat exchanger 12 and the second heat exchanger 13 include a first side and a second side. The flash steam in the LNG liquid cargo tank 100 is transported to the methane reforming reactor 11. The outlet of the methane reforming reactor 11 is connected to the inlet of the first side of the first heat exchanger 12, and the outlet of the first side of the first heat exchanger 12 is connected to the anode inlet of the fuel cell 14. Air is transported to the inlet of the first side of the second heat exchanger 13, and the outlet of the first side of the second heat exchanger 13 is connected to the cathode inlet of the fuel cell 14. The anode and cathode outlets of the fuel cell 14 are connected to the afterburning module 15. The electric energy output end of the fuel cell 14 is connected to the converter 16 and outputs outward;

[0045] The outlet of the second side of the first heat exchanger 12 is connected to the inlet of the second side of the second heat exchanger 13, and the outlet of the second side of the second heat exchanger 13 is connected to the emission end 17. The emission port of the afterburning module 15 is connected to the inlet of the second side of the first heat exchanger 12, the inlet of the second side of the second heat exchanger 13, and the emission end 17 through three branches, and on each branch, an on-off valve is provided.

[0046] It should be noted that the fuel cell 14 in this embodiment is a solid oxide fuel cell (SOFC). As a highly efficient energy conversion device, SOFC shows great potential as a power option due to its high efficiency, strong fuel adaptability, and recoverable high-temperature waste heat. Compared with traditional internal combustion engines, SOFC can not only significantly reduce greenhouse gas emissions but also effectively reduce the emissions of harmful substances such as NO X etc.

[0047] In the power generation system of the LNG carrier of this application, the flash gas (vaporized natural gas, mainly composed of methane gas) generated in the LNG cargo tank 100 is first transported to the methane reforming reactor 11, and water is also input into the methane reforming reactor 11. The water and the flash gas undergo a reforming reaction in the methane reforming reactor 11.

[0048] Among them, the reaction formula in the methane reforming reactor 11 is:

[0049]

[0050]

[0051] After that, the reaction products of the methane reforming reactor 11 enter the first side of the first heat exchanger 12 to be heated up and then enter the anode of the fuel cell 14 to undergo an electrochemical reaction. At the same time, the air is preheated and heated up by the second heat exchanger 13 and then enters the cathode of the fuel cell 14 to undergo an electrochemical reaction.

[0052] Among them, the reaction formula in the fuel cell 14 is:

[0053]

[0054] After that, the charges generated by the fuel cell 14 enter the converter 16, which is used to convert them into the rated voltage of the ship and then output for power supply to provide power for the ship's navigation. Since the amount of flash gas generated in the LNG cargo tank 100 is sufficient, the electric energy generated by the fuel cell 14 is sufficient to fully supply the power demand for the ship's navigation. Therefore, even without setting an internal combustion engine power, it is sufficient for use. In addition, the reaction products at the anode outlet of the fuel cell 14 contain a large amount of water and a small amount of unreacted methane, while the high-temperature gas at the cathode outlet of the fuel cell 14 is the unreacted air that is not completely reacted. The tail gases at the anode and cathode of the fuel cell 14 are transported to the afterburning chamber 152 in the afterburning module 15 for combustion.

[0055] Among them, the reaction formula in the afterburning chamber 152 is:

[0056]

[0057] In summary, the power generation system of the LNG carrier of the present application can consume LNG flash gas as fuel for power generation, without the need to consume electricity to maintain low temperature to prevent the evaporation of re-liquefied LNG. Therefore, the re-liquefaction system can be discarded, the fuel management system on the ship can be simplified, the energy consumption can be greatly reduced, and at the same time, the ship structure can be optimized, the space utilization rate of the ship can be improved, and it is helpful to increase the loading capacity of the LNG carrier. At the same time, in the LNG power generation system of the present application, the reaction products after the fuel cell 14 and post-combustion hardly produce any harmful emissions, and there are almost no other pollutants released except carbon dioxide. Although CO 2 is still a greenhouse gas, compared with traditional internal combustion engines or re-liquefaction equipment, the carbon footprint of the fuel cell power generation of the power generation system of the present application is much smaller, so the emission of greenhouse gases can be reduced. Further, since the amount of flash gas generated in the LNG cargo tank 100 is large enough, the LNG carrier power generation system of the present application can be used as the navigation and ship-wide power source of the LNG carrier, thereby optimizing the internal combustion engine configuration, optimizing the space occupancy rate on the one hand, and providing assistance for realizing low-carbon emissions of the ship on the other hand.

[0058] All in all, the present application uses the fuel cell 14 as the main power generation device of the LNG carrier, and with its efficient, flexible and environmentally friendly characteristics, provides a better choice than traditional re-liquefaction devices. It can not only effectively solve the problem of evaporation gas, but also significantly improve the energy utilization efficiency, reduce the operating cost, reduce environmental pollution, and make an important contribution to realizing green shipping.

[0059] In the LNG carrier power generation system of the present application, for the high-temperature tail gas discharged from the discharge port of the post-combustion module 15, three discharge branch roads are reserved in the solution of the present application, and on-off valves are arranged on each branch road, so that the high-temperature tail gas can be selectively used for preheating air, preheating methane fuel or directly discharging according to needs.

[0060] For example, if the temperature of the fuel entering the first heat exchanger 12 is relatively high and already meets the temperature requirement for entering the fuel cell 14, at this time, only the high-temperature tail gas discharged from the post-combustion of the post-combustion module 15 needs to be introduced into the second side of the second heat exchanger 13, so as to preheat the air more effectively.

[0061] For another example, if the temperature of the fuel entering the first heat exchanger 12 is not lower than the temperature of the high-temperature tail gas, at this time, only the high-temperature tail gas discharged from the post-combustion module 15 needs to be introduced into the second side of the second heat exchanger 13, so as to avoid the reduction of the fuel temperature caused by the heat exchange process through the first heat exchanger 12, thereby ensuring the reaction efficiency in the subsequent fuel cell 14.

[0062] For another example, if the temperature of the fuel entering the first heat exchanger 12 is much lower than the temperature of the high-temperature tail gas, the high-temperature tail gas of the post-combustion module 15 can first enter the second side of the first heat exchanger 12 to preheat the fuel, and then enter the second side of the second heat exchanger 13 to preheat the air, thereby making more full use of the heat of the high-temperature tail gas.

[0063] For yet another example, if the discharge amounts of the products at the anode and cathode of the fuel cell 14 are very small, the combustion temperature in the post-combustion module 15 is relatively low, the discharge amount of the combustion tail gas is relatively low, and the tail gas temperature is also relatively low. And the air entering the second heat exchanger 13 may have been preheated by other preheating devices first and the temperature is already higher than the tail gas temperature of the post-combustion module 15. At this time, the tail gas of the post-combustion module 15 can be directly transported to the discharge end 17.

[0064] In summary, in the power generation system of the LNG carrier of the present application, the tail gas discharged by the combustion of the post-combustion module 15 is respectively connected to the first heat exchanger 12, the second heat exchanger 13 and the discharge end 17 through three branches provided with on-off valves, so as to selectively use the high-temperature tail gas for preheating air, preheating methane fuel or directly discharging according to needs, thereby making more reasonable and effective use of the heat of the combustion tail gas of the post-combustion module 15, realizing temperature complementarity and selective cascade utilization of energy, improving the cascade utilization rate of the system waste heat, and avoiding the adverse effects brought by unreasonable waste heat utilization to the reaction of the fuel cell 14.

[0065] In some embodiments, as Figure 1 shown, the post-combustion module 15 may include a separator 151 and a post-combustion chamber 152. The anode outlet of the fuel cell 14 is connected to the inlet of the separator 151, and the cathode outlet of the fuel cell 14 is connected to the post-combustion chamber 152. The separator 151 includes a first outlet and a second outlet. The first outlet of the separator 151 is connected to the methane reforming reactor 11, and the second outlet of the separator 151 is connected to the post-combustion chamber 152.

[0066] Since a large amount of water and a small amount of unreacted methane are contained in the outlet reaction products at the anode of the fuel cell 14, the separator 151 can separate a part of the anode outlet products. One part enters the post-combustion chamber 152 for combustion, and the other part of the anode outlet products can enter the methane reforming reactor 11 to continue to participate in the methane wet reforming reaction, realizing the reuse of the anode products, improving the resource utilization rate and reducing waste.

[0067] In some embodiments, proportional valves may be provided at both the first outlet and the second outlet of the separator 151. The proportional valves are used to adjust the gas outlet ratio of the first outlet and the second outlet of the separator 151, so as to distribute the ratio of the anode products transported to the post-combustion chamber 152 and the methane reforming reactor 11.

[0068] In some embodiments, by comparing the temperatures at the exhaust port of the post-combustion module 15, the temperature at the inlet of the first side of the first heat exchanger 12, and the temperature at the inlet of the first side of the second heat exchanger 13, the opening or closing of the on-off valve is controlled, so as to realize the reasonable and efficient utilization of the tail gas heat of the post-combustion module 15.

[0069] In some embodiments, as Figure 2 shown, the three branches connecting the exhaust port of the post-combustion module 15 to the inlet of the second side of the first heat exchanger 12, the inlet of the second side of the second heat exchanger 13, and the discharge end 17 are the first branch A1, the second branch A2, and the third branch A3 respectively. A first on-off valve P1 is provided on the first branch A1, a second on-off valve P2 is provided on the second branch A2, and a third on-off valve P3 is provided on the third branch A3. The first on-off valve P1, the second on-off valve P2, and the third on-off valve P3 can adopt manual switch valves. However, preferably, the LNG carrier power generation system further includes a control module 18, which is communicatively connected to the first on-off valve P1, the second on-off valve P2, and the third on-off valve P3 and controls the opening or closing of each valve.

[0070] In some embodiments, as Figure 2 shown, a first temperature sensor H1 is provided at the exhaust port of the post-combustion module 15, a second temperature sensor H2 is provided at the inlet of the first side of the first heat exchanger 12, and a third temperature sensor H3 is provided at the inlet of the first side of the second heat exchanger 13. The first temperature sensor H1, the second temperature sensor H2, and the third temperature sensor H3 are communicatively connected to the control module 18.

[0071] In this embodiment, the steps for the control module 18 to control the opening or closing of the first on-off valve P1, the second on-off valve P2, and the third on-off valve P3 may include:

[0072] The control module 18 obtains the temperature values of the first temperature sensor H1, the second temperature sensor H2, and the third temperature sensor H3, which are respectively , , ;

[0073] The control module 18 compares the magnitudes of , , and issues corresponding control signals;

[0074] If , the control module 18 controls the first on-off valve P1 to remain open and controls the second on-off valve P2 and the third on-off valve P3 to remain closed; at this time, the high-temperature tail gas passes through the second side of the first heat exchanger 12 and the second side of the second heat exchanger 13 in sequence and then reaches the discharge end 17, realizing the preheating of the flash gas fuel and air;

[0075] If And If, then the control module 18 controls the second on-off valve P2 to remain open and controls the first on-off valve P1 and the third on-off valve P3 to remain closed; at this time, the high-temperature tail gas passes through the second side of the second heat exchanger 13 and then reaches the discharge end 17, realizing the preheating of the air;

[0076] If And If, then the control module 18 controls the third on-off valve to remain open and controls the first on-off valve and the second on-off valve to remain closed; at this time, the high-temperature tail gas directly reaches the discharge end 17.

[0077] In addition, a temperature threshold value can be pre-stored in the control module 18 This temperature threshold value is used to indicate that the fuel temperature entering the fuel cell 14 has reached the required level and preheating is no longer required. Therefore, if When, regardless of And How big the difference is, at this time, the control module 18 can control the first on-off valve P1 to remain closed. If When, then the control module 18 performs a size comparison on , , And issue corresponding control signals.

[0078] In summary, the control module 18 of this embodiment realizes the comprehensive comparison and judgment of the gas temperatures at the discharge port of the afterburner 152, the inlet of the first side of the first heat exchanger 12, and the inlet of the first side of the second heat exchanger 13 based on the temperature data obtained by the first temperature sensor H1, the second temperature sensor H2, and the third temperature sensor H3, and then automatically regulates the discharge path of the high-temperature tail gas discharged from the afterburner 152 to realize the reasonable and efficient reuse of the waste heat of the tail gas.

[0079] In some embodiments, such as Figure 3As shown, the power generation system of the LNG carrier may further include a buffer tank 2, a flow detector 21, and a buffer controller 22. The buffer tank 2 is upstream of the methane reforming reactor 11 and is connected to the pipeline in parallel. A buffer inlet valve M1 is installed at the inlet of the buffer tank 2, a buffer outlet valve M2 is installed at the outlet of the buffer tank 2, and a direct-through valve M3 is installed in the pipeline parallel to the buffer tank 2. The flow detector 21 is disposed on the outlet side of the LNG cargo tank 100, and the buffer controller 22 is communicatively connected to the flow detector 21, the buffer inlet valve M1, the buffer outlet valve M2, and the direct-through valve M3. The buffer controller 22 can obtain the flow rate of the flashed gas output from the LNG cargo tank 100 through the flow detector 21, and then determine whether the flashed gas is excessive. If it is excessive, at this time, the flow detector 21 can open the buffer inlet valve M1 to allow part of the flashed gas to enter the buffer tank 2 for storage, thereby preventing the fuel cell 14 from generating too much unreacted gas and reducing the waste of the flashed gas.

[0080] When using the gas in the buffer tank 2, the buffer controller 22 can control to keep the buffer inlet valve M1 and the buffer outlet valve M2 open.

[0081] It should be noted that a compression device can be installed on the outlet side of the buffer tank 2 to increase the outlet pressure of the buffer tank 2 to meet the subsequent pipeline pressure requirements.

[0082] In some embodiments, a flow rate desired threshold can be pre-stored in the buffer controller 22 ; assuming that the standard methane gas volume required for the fuel cell 14 to reach the high-efficiency power generation level (which can be defined by the designer) is , however, in order to ensure that the flow rate of the flashed gas is sufficient to maintain the high-efficiency power generation of the fuel cell 14, the set flow rate desired threshold is at least not less than the size of the standard methane gas volume .

[0083] Therefore, in this embodiment, it is preferably set that the buffer outlet valve M2 has a check valve characteristic, or an independent check valve is provided at the outlet of the buffer tank 2.

[0084] Furthermore, the steps for the buffer controller 22 to control the opening or closing of the buffer inlet valve M1, the buffer outlet valve M2, and the direct-through valve M3 include:

[0085] The buffer controller 22 obtains the real-time flow rate value as through the flow detector 21;

[0086] The buffer controller 22 determines the size of the real-time flow rate value and the flow rate desired threshold ;

[0087] If , the buffer controller 22 controls the buffer inlet valve M1 and the buffer outlet valve M2 to remain closed, and controls the direct flow valve M3 to remain open, so that the flash gas is directly transported to the methane reforming reactor 11;

[0088] If , the buffer controller 22 controls the buffer inlet valve M1 and the buffer outlet valve M2 to remain open, and controls the direct flow valve M3 to remain open, and then temporarily receives the excessive flash gas through the buffer tank 2.

[0089] In some embodiments, the buffer inlet valve M1 and the direct flow valve M3 can adopt proportional valves, and the buffer controller 22 is used to control the opening ratio of the buffer inlet valve M1 and the direct flow valve M3, so as to divert the flash gas, control part of the flash gas to enter the buffer tank 2, and the flash gas required for power generation is transported to the methane reforming reactor 11 through the direct flow valve M3.

[0090] In some embodiments, as Figure 4 shown, the power output terminal of the converter 16 includes a first interface and a second interface. The first interface is connected to the electrical load device, and the second interface is connected to the energy storage device 3. During the normal navigation of the ship, the electric energy generated by the fuel cell 14 is basically all output from the first interface of the converter 16 to supply the ship's navigation. When there is a surplus of the electric power generated by the fuel cell 14, the excess electric power enters the energy storage device 3 through the second interface of the converter 16 for storage, and is released and used through the energy storage device 3 when the whole ship performs peak shaving and valley filling of electricity consumption.

[0091] In some embodiments, as Figure 4 shown, it includes a waste heat utilization module 5, which includes a first side and a second side. The discharge end 17 is discharged through the first side pipeline of the waste heat utilization module 5. The second side of the waste heat utilization module 5 is introduced with normal temperature water (generally engine room fresh water), and after heat exchange with the high-temperature tail gas discharged from the discharge end 17, the second side of the waste heat utilization module 5 discharges hot water that meets the ship's heat load requirements and leads to the heat user through the pipeline. For example, the waste heat utilization module 5 can be a waste heat boiler.

[0092] In some embodiments, the LNG carrier power generation system further includes a box structure (not shown in the figure) and a temperature control component 4 (see Figure 4 ), at least the fuel cell 14 is in the box structure to facilitate the hoisting of the whole fuel cell 14. Preferably, the fuel cell power generation assembly 1 is concentrated in a box structure as a whole. Among them, the temperature control component 4 generally includes an electric heating rod placed in the box structure and a thermocouple placed in the fuel cell 14. The temperature control component 4 further includes a temperature main controller, and the temperature main controller determines the temperature in the fuel cell 14 through the thermocouple and controls the energization or power-off of the electric heating rod. Through the action of the temperature control component 4, the high-temperature state during the operation of the fuel cell 14 is maintained.

[0093] As Figure 5 and Figure 6 shown, the embodiment of the present application further provides an LNG carrier, which includes a hull and the aforementioned LNG carrier power generation system. The hull includes an engine room 200 and a plurality of LNG cargo tanks 100. The LNG carrier power generation system is arranged at the engine room 200. The electric energy output by the converter 16 of the LNG carrier power generation system is used to drive the main engine of the ship to work.

[0094] Among them, the fuel cell power generation component 1 in the aforementioned LNG carrier power generation system can be placed inside or outside the engine room 200. The buffer tank 2, the energy storage device 3, the waste heat utilization module 5, the temperature control component 4, etc. can be arranged inside the engine room 200.

[0095] The above are only some preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An LNG carrier power generation system, comprising an LNG cargo tank (100), characterized in that: It also includes a fuel cell power generation assembly (1), which includes a methane reforming reactor (11), a first heat exchanger (12), a second heat exchanger (13), a fuel cell (14), a post-combustion module (15), a converter (16) and an exhaust end (17); the first heat exchanger (12) and the second heat exchanger (13) both include a first side and a second side; The flash gas in the LNG cargo tank (100) is transported to the methane reforming reactor (11), the outlet of the methane reforming reactor (11) is connected to the first side inlet of the first heat exchanger (12), and the first side outlet of the first heat exchanger (12) is connected to the anode inlet of the fuel cell (14); The air is delivered to the first side inlet of the second heat exchanger (13), and the first side outlet of the second heat exchanger (13) is connected to the cathode inlet of the fuel cell (14); The anode and cathode outlets of the fuel cell (14) are connected to the post-combustion module (15); The electric energy output end of the fuel cell (14) is connected to the converter (16) and outputs externally; The second side outlet of the first heat exchanger (12) is connected to the second side inlet of the second heat exchanger (13), and the second side outlet of the second heat exchanger (13) is connected to the discharge end (17); The discharge port of the post-combustion module (15) is respectively connected to the second side inlet of the first heat exchanger (12), the second side inlet of the second heat exchanger (13) and the discharge end (17) through three branches, and each branch is provided with an on-off valve.

2. The LNG carrier power generation system according to claim 1, characterized in that: The opening or closing of the on-off valve is controlled by comparing the temperature at the exhaust port of the post-combustion module (15), the temperature at the first side inlet of the first heat exchanger (12), and the temperature at the first side inlet of the second heat exchanger (13).

3. The LNG carrier power generation system according to claim 1, characterized in that: The three branches connecting the discharge port of the post-combustion module (15) with the second side inlet of the first heat exchanger (12), the second side inlet of the second heat exchanger (13) and the discharge end (17) are respectively the first branch, the second branch and the third branch; A first on-off valve is provided on the first branch, a second on-off valve is provided on the second branch, and a third on-off valve is provided on the third branch; It also includes a control module (18) which is in communication with the first on-off valve, the second on-off valve, and the third on-off valve and controls the opening or closing of each valve.

4. The LNG carrier power generation system according to claim 3, characterized in that: A first temperature sensor is arranged at the discharge port of the post-combustion module (15), a second temperature sensor is arranged at the first side inlet of the first heat exchanger (12), and a third temperature sensor is arranged at the first side inlet of the second heat exchanger (13); The first temperature sensor, the second temperature sensor, and the third temperature sensor are communicatively connected to the control module (18).

5. The LNG carrier power generation system according to claim 4, characterized in that: The step of the control module (18) controlling the first on-off valve, the second on-off valve and the third on-off valve to open or close comprises: The control module (18) obtains the temperature values ​​of the first temperature sensor, the second temperature sensor, and the third temperature sensor, which are respectively , , ; The control module (18) , , Perform size comparison and send corresponding control signals; like , the control module (18) controls the first on-off valve to remain open, and controls the second on-off valve and the third on-off valve to remain closed; like and , the control module (18) controls the second on-off valve to remain open, and controls the first on-off valve and the third on-off valve to remain closed; like and , the control module (18) controls the third on-off valve to remain open, and controls the first on-off valve and the second on-off valve to remain closed.

6. The LNG carrier power generation system according to any one of claims 1 to 5, characterized in that: The afterburning module (15) comprises a separator (151) and an afterburning chamber (152); The anode outlet of the fuel cell (14) is connected to the inlet of the separator (151), and the cathode outlet of the fuel cell (14) is connected to the post-combustion chamber (152); The separator (151) comprises a first outlet and a second outlet, the first outlet of the separator (151) is connected to the methane reforming reactor (11), and the second outlet of the separator (151) is connected to the post-combustion chamber (152).

7. The LNG carrier power generation system according to claim 6, characterized in that: Proportional valves are provided at both the first outlet and the second outlet of the separator (151), and the proportional valves are used to adjust the gas outlet ratio between the first outlet and the second outlet of the separator (151).

8. The LNG carrier power generation system according to claim 1, characterized in that: It also includes a buffer tank (2), a flow detector (21) and a buffer controller (22); The buffer tank (2) is located upstream of the methane reforming reactor (11) and is connected to a pipeline in parallel. A buffer inlet valve is installed at the inlet of the buffer tank (2), a buffer outlet valve is installed at the outlet of the buffer tank (2), and a through valve is installed in the pipeline connected in parallel with the buffer tank (2); The flow detector (21) is arranged at the outlet side of the LNG liquid cargo tank (100), and the buffer controller (22) is communicatively connected with the flow detector (21), the buffer inlet valve, the buffer outlet valve, and the through valve.

9. The LNG carrier power generation system according to claim 8, characterized in that: The buffer controller (22) pre-stores a flow expectation threshold The steps of the buffer controller (22) controlling the buffer inlet valve, the buffer outlet valve, and the through valve to open or close include: The buffer controller (22) obtains the real-time flow value through the flow detector (21). ; The buffer controller (22) determines the real-time flow value Expected flow threshold size; like , the buffer controller (22) controls the buffer inlet valve and the buffer outlet valve to remain in a closed state, and controls the through valve to remain in an open state; like , the buffer controller (22) controls the buffer inlet valve and the buffer outlet valve to remain in an open state, and controls the through valve to remain in an open state.

10. The LNG carrier power generation system according to claim 1, characterized in that: The power output end of the converter (16) comprises a first interface and a second interface, the first interface being connected to a power load device, and the second interface being connected to an energy storage device (3).

11. The LNG carrier power generation system according to claim 1, characterized in that: It comprises a waste heat utilization module (5), which comprises a first side and a second side, the discharge end (17) is discharged through the first side pipeline of the waste heat utilization module (5), and the second side of the waste heat utilization module (5) is fed with normal temperature water.

12. The LNG carrier power generation system according to claim 1, characterized in that: It also includes a box structure and a temperature control component (4), wherein at least the fuel cell (14) is located in the box structure; The temperature control component (4) comprises an electric heating rod disposed in the box structure and a thermocouple disposed in the fuel cell (14). The temperature control component (4) further comprises a temperature controller, which determines the temperature in the fuel cell (14) through the thermocouple and controls the power on or off of the electric heating rod.

13. An LNG carrier, characterized in that: A LNG carrier power generation system comprising a hull and any one of claims 1 to 12; The hull comprises an engine room (200) and a plurality of LNG liquid cargo tanks (100), and the LNG carrier power generation system is arranged in the engine room (200).

Images