LNG carrier power generation system and LNG carrier

Abstract

The present application provides an LNG carrier power generation system and an LNG carrier. The power generation system includes a fuel cell power generation assembly, including a methane reforming reactor, first and second heat exchangers, a fuel cell, an afterburning module, a converter, and an exhaust port. LNG cargo tank flash gas is transported to the methane reforming reactor, and the reforming product enters the 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. The anode and cathode outlets are connected to the afterburning module, and the fuel cell power output end is connected to the converter and output. The second side outlet of the first heat exchanger is connected to the second side inlet of the second heat exchanger, and the second side outlet of the second heat exchanger is connected to the exhaust port. The exhaust gas from the afterburning module is connected to the second side inlet of the first heat exchanger, the second side inlet of the second heat exchanger, and the exhaust port through three branches, each branch being provided with an on-off valve. The present application uses LNG flash gas as fuel, generates electricity through fuel cells to supply ship power, reduces carbon emissions, abandons reliquefaction, and realizes the rational use of waste heat.

Description

Technical Field

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

[0002] Boil-off gas (BOG) refers to the gas produced by the vaporization of liquid cargo within a liquid cargo carrier due to heat exchange or pressure changes. For example, on LNG (liquefied natural gas) carriers, BOG is primarily formed by the evaporation of LNG due to heat, and its primary component is methane (CH4). This not only reduces the amount of LNG cargo but also increases pressure within the cargo tanks. If this boil-off gas is not effectively handled, the excessive pressure could damage the cargo tank structure and even pose safety risks.

[0003] Traditionally, in order to prevent excessive pressure in the LNG cargo tank and to minimize the waste of LNG flash gas, BOG is usually reliquefied and returned to the cargo tank. Existing reliquefaction systems usually include equipment such as multi-stage compressors, expanders, heat exchangers and condensers. Their complex process flow results in large equipment volumes, making it difficult to efficiently arrange them within the limited space of a ship. At the same time, the reliquefaction system requires a large amount of electricity to maintain low temperature conditions to prevent LNG from evaporating, and this electricity often comes from burning more fuel, forming a vicious cycle. In addition, during system operation, some residual BOG that is not fully liquefied or BOG that exceeds the reliquefaction processing capacity needs to be discharged through flaring, which not only wastes energy but also further increases greenhouse gas emissions, which is extremely unfavorable to environmental protection requirements.

[0004] In addition, as relevant international organizations have increasingly stringent requirements on ship carbon emissions and energy efficiency, LNG carriers face multiple challenges: on the one hand, it is necessary to optimize the space occupied by the BOG reliquefaction treatment system and the ship's energy efficiency; on the other hand, traditional ship propulsion systems still mainly rely on fossil fuel internal combustion engines for power, and their carbon emission levels are difficult to meet the industry's sustainable development goals of energy conservation and emission reduction. Summary of the Invention

[0005] The purpose of this application is to provide an LNG carrier power generation system and an LNG carrier, which can use LNG flash gas as fuel and generate electricity through solid oxide fuel cells to supply ship power, significantly reducing carbon emissions, and can streamline the reliquefaction system, avoiding energy consumption in the reliquefaction process, and can also achieve efficient and reasonable utilization of exhaust waste heat after power generation.

[0006] In a first aspect, a power generation system for an LNG carrier is provided, comprising an LNG cargo tank and a fuel cell power generation assembly. 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 an exhaust port. The first heat exchanger and the second heat exchanger each comprise a first side and a second side. Flash gas from the LNG cargo tank is transported to the methane reforming reactor, the methane reforming reactor outlet being connected to the first side inlet of the first heat exchanger, which in turn is connected to the anode inlet of the fuel cell. Air is transported to the first side inlet of the second heat exchanger, which in turn 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 fuel cell power output is connected to the converter and output externally.

[0007] The second side outlet of the first heat exchanger is connected to the second side inlet of the second heat exchanger, which is in turn connected to the exhaust port. The exhaust port of the post-combustion module is connected to the second side inlet of the first heat exchanger, the second side inlet of the second heat exchanger, and the exhaust port via three branches, each of which is equipped with an on-off valve.

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

[0009] In an implementable solution, the three branches connecting the exhaust port of the post-combustion module and the second side inlet of the first heat exchanger, the second side inlet of the second heat exchanger and the exhaust end 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; and a control module is also included, which is communicated 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.

[0010] In one feasible solution, a first temperature sensor is provided at the exhaust port of the post-combustion module, a second temperature sensor is provided at the first side inlet of the first heat exchanger, and a third temperature sensor is provided at the first side inlet 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 step of the control module controlling the first on-off valve, the second on-off valve, and the third on-off valve to open or close includes:

[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] Control module pair 、 、 Perform size comparison and issue corresponding control signals;

[0014] like , 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] like 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] like 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 one feasible solution, the post-combustion module includes a separator and a post-combustion chamber; the anode outlet of the fuel cell is connected to the separator inlet, 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, 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 between the first outlet and the second outlet of the separator.

[0019] In an implementable solution, the LNG carrier power generation system also includes a buffer tank, a flow detector and a buffer controller; the buffer tank is located 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 straight-through valve is installed in the pipeline parallel to the buffer tank; the flow detector is arranged on the outlet side of the LNG liquid cargo tank, and the buffer controller is communicatively connected with the flow detector, the buffer inlet valve, the buffer outlet valve and the straight-through valve.

[0020] In one feasible solution, a flow expectation threshold is pre-stored in the buffer controller. The steps of the buffer controller controlling the buffer inlet valve, buffer outlet valve, and through valve to open or close include:

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

[0022] Buffer controller determines the real-time flow value and traffic expectation threshold size;

[0023] like , the buffer controller 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;

[0024] like , the buffer controller controls the buffer inlet valve and the buffer outlet valve to remain in the open state, and controls the through valve to remain in the open state.

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

[0026] In one feasible 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 one feasible solution, the LNG carrier power generation system also 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, and the temperature control component also includes a temperature controller, which determines the temperature in the fuel cell through the thermocouple and controls the power on or off of the electric heating rod.

[0028] In a second aspect, an LNG carrier is also provided, comprising a hull and the aforementioned LNG carrier power generation system; the hull comprises an engine room and several LNG liquid cargo tanks, and the LNG carrier power generation system is arranged in the engine room.

[0029] Compared to the prior art, the present invention offers at least the following advantages: the LNG carrier power generation system of the present invention can use LNG flash gas as fuel to generate electricity, eliminating the need to consume electricity to maintain low temperatures to prevent evaporation of reliquefied LNG. This eliminates the need for a reliquefaction system, simplifies the onboard fuel management system, and significantly reduces energy consumption. Furthermore, the system optimizes the ship's structure, improves ship space utilization, and contributes to increasing the cargo capacity of LNG carriers. Furthermore, the LNG power generation system of the present invention, including the fuel cell and post-combustion reaction products, produces virtually no harmful emissions, with virtually no other pollutants released besides carbon dioxide. While CO2 remains a greenhouse gas, the carbon footprint of the fuel cell power generation system of the present invention is significantly smaller than that of traditional internal combustion engines or reliquefaction equipment, thereby reducing greenhouse gas emissions. Furthermore, because the amount of flash gas generated in the LNG cargo tanks is sufficient, the LNG carrier power generation system of the present invention can serve as the ship's navigation and overall power source, thereby optimizing the internal combustion engine configuration, improving space utilization, and contributing to achieving low-carbon emissions for ships.

[0030] At the same time, in the LNG carrier power generation system of the present application, the exhaust gas emitted by the after-combustion module is connected to the first heat exchanger, the second heat exchanger and the discharge end respectively through three branches provided with on-off valves, so that the high-temperature exhaust gas can be selectively used for preheating air, preheating methane fuel or directly discharged as needed, thereby more reasonably and effectively utilizing the heat of the combustion exhaust gas of the after-combustion module, realizing temperature complementarity and selective cascade utilization of energy, improving the cascade utilization rate of the system's waste heat, and avoiding the adverse effects of unreasonable waste heat utilization on 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 is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This 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 This 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 A schematic diagram of the composition of a power generation system for an LNG carrier with a buffer tank, shown in an embodiment of the present application.

[0035] Figure 4 This 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 This is a schematic diagram of the composition of an LNG carrier shown in an embodiment of the present application.

[0037] Figure 6 This 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 assembly; 11. Methane reforming reactor; 12. First heat exchanger; 13. Second heat exchanger; 14. Fuel cell; 15. After-combustion module; 151. Separator; 152. After-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. Through valve; 3. Energy storage device; 4. Temperature control assembly; 5. Waste heat utilization module; 100. LNG cargo tank; 200. Engine room. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein 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 accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0041] The inventors of this application proposed the technical solution of this application for the purpose of, on the one hand, improving the utilization rate of LNG flash gas and hoping to abandon the reliquefaction system to optimize the hull structure; on the other hand, to achieve further energy conservation and emission reduction.

[0042] At the same time, the inventors also discovered that in conventional solid oxide fuel cell power generation systems, gases that have not completely reacted at the anode and cathode of the fuel cell are transported to the afterburner for combustion. Because the exhaust gas discharged from the exhaust port of the afterburner is quite hot, the usual treatment method is to use this exhaust gas to preheat the air entering the fuel cell, and then discharge the exhaust gas after preheating. However, even after being used to preheat the air, the exhaust gas discharged from the afterburner still maintains a relatively high temperature. If it is discharged directly, a large amount of heat will be wasted, resulting in low energy utilization, which is actually an indirect waste of flash gas. In addition, in some power generation systems, the exhaust gas is further used to preheat the fuel gas after preheating the air. However, in certain specific circumstances, the temperature of the exhaust gas discharged from the afterburner may be lower than that of the fuel gas. At this time, if the exhaust gas is allowed to exchange heat with the fuel gas, not only will it fail to achieve effective preheating, but it will also lower the temperature of the fuel gas, resulting in side effects, thereby reducing the reaction efficiency and adding additional burden to the reaction process of the fuel cell.

[0043] In order to solve the above technical problems, Figure 1 As 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 including 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 port 17.

[0044] 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. The first side outlet of the first heat exchanger 12 is connected to the anode inlet of the fuel cell 14. Air is transported to the first side inlet of the second heat exchanger 13. 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 power output of the fuel cell 14 is connected to the converter 16 and outputs externally.

[0045] The second side outlet of the first heat exchanger 12 is connected to the second side inlet of the second heat exchanger 13, which is in turn connected to the exhaust port 17. The exhaust port of the post-combustion module 15 is connected to the second side inlet of the first heat exchanger 12, the second side inlet of the second heat exchanger 13, and the exhaust port 17 via three branches, each of which is equipped with an on-off valve.

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

[0047] In the LNG carrier power generation system of the present application, the flash gas (gasified natural gas, the main component of which is methane gas) generated in the LNG liquid cargo tank 100 is first transported to the methane reforming reactor 11. Water is also input into the methane reforming reactor 11, and the water and the flash gas undergo a reforming reaction in the methane reforming reactor 11.

[0048] The reaction formula in the methane reforming reactor 11 is:

[0049]

[0050]

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

[0052] The reaction equation in the fuel cell 14 is:

[0053]

[0054] Afterwards, the charge generated by the fuel cell 14 enters the converter 16, which is used to convert it into the rated voltage for the ship and then output the 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 electricity generated by the fuel cell 14 is sufficient to fully supply the power needs of the ship's navigation, so it is sufficient even if the internal combustion engine power is not installed. 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 contains incompletely reacted air. The exhaust gas from the anode and cathode of the fuel cell 14 is transported to the afterburner chamber 152 in the afterburner module 15 for combustion.

[0055] The reaction equation in the afterburner 152 is:

[0056]

[0057] In summary, the LNG carrier power generation system of the present application can use LNG flash gas as fuel to generate electricity, eliminating the need to consume electricity to maintain low temperatures to prevent evaporation of reliquefied LNG. Therefore, the reliquefaction system can be eliminated, simplifying the onboard fuel management system and significantly reducing energy consumption. Furthermore, the ship structure can be optimized, improving ship space utilization, and contributing to increased LNG carrier loading capacity. Furthermore, the LNG power generation system of the present application, the fuel cell 14, and the reaction products after post-combustion, produce virtually no harmful emissions, with virtually no other pollutants released other than carbon dioxide. Although CO2 is still a greenhouse gas, the carbon footprint of the fuel cell power generation system of the present application is much smaller than that of traditional internal combustion engines or reliquefaction equipment, thereby reducing greenhouse gas emissions. Furthermore, because the amount of flash gas generated in the LNG cargo tank 100 is sufficient, the LNG carrier power generation system of the present application can serve as the LNG carrier's navigation and overall ship power source, thereby optimizing the internal combustion engine configuration, not only improving space occupancy but also contributing to achieving low-carbon emissions for ships.

[0058] In summary, this application utilizes fuel cells 14 as the primary power generation device for LNG carriers. With their high efficiency, flexibility, and environmental friendliness, they offer an alternative to traditional reliquefaction systems. Not only does this effectively address the boil-off gas issue, it also significantly improves energy efficiency, reduces operating costs, and minimizes environmental pollution, making a significant contribution to achieving green shipping.

[0059] In the LNG carrier power generation system of the present application, the high-temperature exhaust gas discharged from the exhaust port of the post-combustion module 15 has three exhaust branches reserved in the solution of the present application, and each branch is provided with an on-off valve, so that the high-temperature exhaust gas can be selectively used to preheat air, preheat methane fuel or directly discharged as needed.

[0060] For example, if the temperature of the fuel entering the first heat exchanger 12 is high enough to meet the temperature requirement of the fuel cell 14, then the high-temperature exhaust gas discharged by the post-combustion module 15 only needs to be passed into the second side of the second heat exchanger 13 to preheat the air more effectively.

[0061] For another example, if the temperature of the fuel entering the first heat exchanger 12 is no lower than the temperature of the high-temperature exhaust gas, it is only necessary to pass the high-temperature exhaust gas discharged from the post-combustion module 15 into the second side of the second heat exchanger 13, thereby avoiding the heat exchange process through the first heat exchanger 12 causing the fuel temperature to drop, 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 exhaust gas, the high-temperature exhaust gas from the afterburning 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 effective use of the heat of the high-temperature exhaust gas.

[0063] For example, if the product discharge from the anode and cathode of the fuel cell 14 is minimal, the combustion temperature in the post-combustion module 15 is low, resulting in a low exhaust gas volume and temperature. Furthermore, the air entering the second heat exchanger 13 may have already been preheated by other preheating devices, resulting in a temperature higher than the exhaust gas temperature from the post-combustion module 15. In this case, the exhaust gas from the post-combustion module 15 can be directly delivered to the exhaust port 17.

[0064] In summary, in the LNG carrier power generation system of the present application, the exhaust gas emitted by the after-combustion module 15 is connected to the first heat exchanger 12, the second heat exchanger 13 and the exhaust port 17 respectively through three branches provided with on-off valves, so that the high-temperature exhaust gas can be selectively used for preheating air, preheating methane fuel or directly discharged as needed, thereby more reasonably and effectively utilizing the heat of the combustion exhaust gas of the after-combustion module 15, realizing temperature complementarity and selective cascade utilization of energy, improving the cascade utilization rate of the system's waste heat, and avoiding the adverse effects of unreasonable waste heat utilization on the reaction of the fuel cell 14.

[0065] In some embodiments, as Figure 1 As 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 the outlet reaction products of the anode of the fuel cell 14 contain a large amount of water and a small amount of unreacted methane, the separator 151 can separate a part of the anode outlet products, a part of which enters the after-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, thereby realizing the reuse of the anode products, improving resource utilization 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, and the proportional valves are used to adjust the gas outlet ratio of the first outlet and the second outlet of the separator 151, thereby allocating the ratio of the anode product to be delivered to the post-combustion chamber 152 and the methane reforming reactor 11.

[0068] In some embodiments, by comparing the temperature at the exhaust port of the afterburning 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, the opening or closing of the on-off valve is controlled, thereby achieving reasonable and efficient utilization of the exhaust heat of the afterburning module 15.

[0069] In some embodiments, as Figure 2 As shown, the exhaust port of the post-combustion module 15 is connected to the second side inlet of the first heat exchanger 12, the second side inlet of the second heat exchanger 13, and the exhaust port 17 through three branches: a first branch A1, a second branch A2, and a third branch A3. 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. Manual on / off valves P1, P2, and P3 can be used for the first, second, and third on / off valves, but preferably, the LNG carrier power generation system also includes a control module 18, which is in communication with the first, second, and third on / off valves P1, P2, and P3 and controls the opening and closing of each valve.

[0070] In some embodiments, as Figure 2 As 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 first side inlet of the first heat exchanger 12, and a third temperature sensor H3 is provided at the first side inlet of the second heat exchanger 13. The first temperature sensor H1, the second temperature sensor H2, and the third temperature sensor H3 are in communication with the control module 18.

[0071] In this embodiment, the step of the control module 18 controlling the first on-off valve P1, the second on-off valve P2, and the third on-off valve P3 to open or close 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] 18 pairs of control modules 、 、 Perform size comparison and issue corresponding control signals;

[0074] like , 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 exhaust 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, thereby preheating the flash gas fuel and air;

[0075] like and , 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 exhaust gas passes through the second side of the second heat exchanger 13 and reaches the discharge end 17, achieving preheating of the air;

[0076] 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; at this time, the high-temperature exhaust gas directly reaches the exhaust end 17.

[0077] In addition, a temperature threshold value can be pre-stored in the control module 18 , this temperature threshold is used to indicate that the temperature of the fuel entering the fuel cell 14 has reached the required level and no further preheating is required. When, regardless of and The control module 18 can control the first on-off valve P1 to remain closed. When the control module 18 、 、 Perform size comparison and send corresponding control signals.

[0078] In summary, the control module 18 of this embodiment realizes a comprehensive comparison and judgment of the gas temperature at the exhaust port of the afterburner 152, the first side inlet of the first heat exchanger 12, and the first side inlet 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 adjusts the emission path of the high-temperature exhaust gas emitted by the afterburner 152, thereby realizing the reasonable and efficient reuse of the waste heat of the exhaust gas.

[0079] In some embodiments, as Figure 3As shown, the LNG carrier power generation system may also include 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 connected in parallel to the pipeline. 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 through valve M3 is installed in the pipeline parallel to the buffer tank 2. The flow detector 21 is located at the outlet of the LNG cargo tank 100. The buffer controller 22 is communicatively connected to the flow detector 21, the buffer inlet valve M1, the buffer outlet valve M2, and the through valve M3. The buffer controller 22 can detect the flow rate of flash gas output from the LNG cargo tank 100 through the flow detector 21 and determine whether the flash gas is excessive. If so, the flow detector 21 can open the buffer inlet valve M1 to allow some flash gas to enter the buffer tank 2 for pre-storage, thereby preventing the fuel cell 14 from generating excessive unreacted gas and reducing flash gas waste.

[0080] When the gas in the buffer tank 2 is used, the buffer controller 22 may control the buffer inlet valve M1 and the buffer outlet valve M2 to remain open.

[0081] It should be noted that a compression device may 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, the buffer controller 22 may pre-store a flow expectation threshold value Assume that the standard methane gas amount required for the fuel cell 14 to achieve an efficient power generation level (which can be defined by the designer) is However, in order to ensure that the flow rate of the flash gas is sufficient to maintain the efficient power generation of the fuel cell 14, the flow rate threshold is set to At least not less than the standard methane gas volume size.

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

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

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

[0086] Buffer controller 22 determines the real-time value of flow and traffic expectation threshold size;

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

[0088] like , the buffer controller 22 controls the buffer inlet valve M1 and the buffer outlet valve M2 to remain open, and controls the through valve M3 to remain open, thereby temporarily absorbing the excess flash gas through the buffer tank 2.

[0089] In some embodiments, the buffer inlet valve M1 and the straight-through 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 straight-through valve M3, thereby diverting the flash gas and controlling part of the flash gas to enter the buffer tank 2, so that the flash gas required for power generation is transported to the methane reforming reactor 11 via the straight-through valve M3.

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

[0091] In some embodiments, as Figure 4 As shown, the waste heat utilization module 5 includes a first side and a second side. A discharge port 17 is discharged through a pipeline on the first side of the waste heat utilization module 5. Normal temperature water (typically engine room fresh water) is introduced into the second side of the waste heat utilization module 5. This water exchanges heat with the high-temperature exhaust gas discharged from the discharge port 17, thereby discharging hot water that meets the ship's heat load requirements from the second side of the waste heat utilization module 5 and passing it through a pipeline to a heat user. For example, the waste heat utilization module 5 may 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 located within the housing structure to facilitate the hoisting of the entire fuel cell 14. Preferably, the entire fuel cell power generation assembly 1 is centralized within a housing structure. The temperature control assembly 4 generally includes an electric heating rod placed within the housing structure and a thermocouple placed within the fuel cell 14. The temperature control assembly 4 also includes a temperature controller, which uses the thermocouple to determine the temperature within the fuel cell 14 and control the powering on and off of the electric heating rod. The temperature control assembly 4 maintains a high temperature during fuel cell operation.

[0093] like Figure 5 and Figure 6 As shown, an embodiment of the present application also provides an LNG carrier, comprising 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 in the engine room 200. The power outputted by the converter 16 of the LNG carrier power generation system is used to drive the ship's main engine.

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

[0095] The foregoing description is merely a partial list of preferred embodiments of the present application and is not intended to limit the present application. Persons skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection 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; 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 power output end of the fuel cell (14) is connected to the converter (16) and outputs power to the outside; 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 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 a first branch, a second branch and a third branch respectively; 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; A first temperature sensor is provided at the discharge port of the post-combustion module (15), a second temperature sensor is provided at the first side inlet of the first heat exchanger (12), and a third temperature sensor is provided at the first side inlet of the second heat exchanger (13); It also includes a control module (18) that is in communication with each on-off valve and controls the opening or closing of each valve, and is in communication with each temperature sensor; The control module (18) pre-stores a temperature threshold , the temperature threshold It is used to indicate that the temperature of the fuel entering the fuel cell 14 has reached the required level; the steps of the control module (18) controlling the opening or closing of each on-off valve include: 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) determines and The size of , then control the first on-off valve to remain closed; if , then continue with the following steps; The control module (18) 、 、 Perform size comparison and issue 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.

2. The LNG carrier power generation system according to claim 1, characterized in that: The afterburning module (15) includes 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).

3. The LNG carrier power generation system according to claim 2, 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).

4. 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 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.

5. The LNG carrier power generation system according to claim 4, 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 value of the flow and traffic expectation 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.

6. 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, wherein the first interface is connected to an electrical load device, and the second interface is connected to an energy storage device (3).

7. 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, wherein the discharge end (17) is discharged through the first side pipeline of the waste heat utilization module (5), and normal temperature water is introduced into the second side of the waste heat utilization module (5).

8. 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), at least the fuel cell (14) is located in the box structure; The temperature control assembly (4) includes an electric heating rod placed in the box structure and a thermocouple placed in the fuel cell (14). The temperature control assembly (4) also includes a temperature controller. The temperature controller determines the temperature in the fuel cell (14) through the thermocouple and controls the power on or off of the electric heating rod.

9. An LNG carrier, characterized in that: A LNG carrier power generation system comprising a hull and any one of claims 1 to 8; 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).

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