System and method for supplying fuel to ammonia gas turbine of ship

Abstract

The present invention relates to a ship provided with a gas turbine using ammonia as fuel. The ammonia gas turbine fuel supply system according to the present invention comprises: a gas turbine for generating electricity by using gaseous ammonia as fuel; an ammonia storage tank for storing ammonia in a liquid state; an ammonia fuel supply unit for supplying gaseous ammonia fuel to the gas turbine; an ammonia condensation unit for condensing ammonia boil-off gas generated in the ammonia storage tank and collecting the condensed matter into the ammonia storage tank; an ammonia treatment unit for treating ammonia in purging gas generated while purging at least one of the ammonia fuel supply unit or the ammonia condensation unit; a waste heat recovery unit for generating electricity by recovering waste heat from exhaust gas discharged from the gas turbine while circulating supercritical carbon dioxide; and a heat source supply unit for supplying the ammonia fuel supply unit with heat energy or steam heat energy generated in the waste heat recovery unit.

Description

Ammonia gas turbine fuel supply system and method for a ship

[0001] The present invention relates to a ship equipped with a gas turbine that uses ammonia as fuel.

[0002] The International Maritime Organization (IMO), a specialized agency of the United Nations established to internationally unify shipping routes, traffic rules, port facilities, etc., has also set a goal of reducing greenhouse gases by 50% by 2050 and 100% by 2100 (GHG Zero Emission) compared to 2008, and it is expected that regulations in each country and region will be strengthened accordingly.

[0003] According to the Energy Efficiency Design Index (EEDI), a mandatory carbon dioxide reduction regulation applied by the IMO to new ships, the initial EEDI announcement stipulated that EEDI Phase 1 would be applied, reducing carbon dioxide emissions by 10% in 2015 based on carbon dioxide emissions from 2013 to 2015, and that it would be strengthened and applied by one stage every five years, with Phase 3 to be applied in 2025. However, for LPG carriers, EEDI Phase 3 will be applied early starting in 2022, just two years after the application of EEDI Phase 2. As such, regulations on carbon dioxide emissions are being rapidly strengthened, and for LPG carriers of 15,000 DWT or more, if the standards of Phase 4 (40% reduction in carbon dioxide emissions) or higher are applied in the future, it may be difficult to achieve carbon dioxide emission regulations with LPGCs that currently use LPG as fuel.

[0004] Accordingly, various studies are being conducted on eco-friendly ship fuels that can reduce carbon dioxide emissions, and recently, technology is being developed for ships that can use ammonia as fuel along with fuels such as LNG or LPG.

[0005] Ammonia (NH3) is a substance in which three hydrogen atoms are bonded to one nitrogen atom. It can form strong hydrogen bonds between molecules, making it easy to liquefy. At normal pressure, its boiling point is approximately -33.34℃, and its melting point is approximately -77.73℃.

[0006] This ammonia is easier to store than LNG and does not emit any carbon dioxide, so it is attracting attention as an eco-friendly ship fuel that can respond to the trend of strengthening international greenhouse gas emission standards.

[0007] Accordingly, the present invention aims to provide an ammonia gas turbine fuel supply system capable of complying with greenhouse gas emission regulations for ships, which will be strengthened in the future, by using ammonia, a chemical substance that has been used on land for over 100 years and whose supply chain, including production, storage, transportation, and supply, has been sufficiently verified, as fuel for ships.

[0008] In particular, the purpose is to provide a system and method for supplying ammonia gas turbine fuel for a ship, which can improve energy efficiency by storing ammonia as fuel in a liquid form, vaporizing the liquid ammonia to supply gaseous ammonia to an engine, and recovering waste heat of exhaust gas to vaporize the liquid ammonia.

[0009] According to one aspect of the present invention for achieving the above-described object, an ammonia gas turbine fuel supply system is provided, including: a gas turbine that generates electricity using gaseous ammonia as fuel; an ammonia storage tank that stores liquid ammonia; an ammonia fuel supply unit for supplying gaseous ammonia fuel to the gas turbine; an ammonia condenser unit for condensing ammonia evaporation gas generated in the ammonia storage tank and recovering it to the ammonia storage tank; an ammonia treatment unit for processing ammonia in a purging gas generated while purging at least one of the ammonia fuel supply unit and the ammonia condenser unit; a waste heat recovery unit for generating electricity by recovering waste heat of exhaust gas discharged from the gas turbine while circulating supercritical carbon dioxide; and a heat source supply unit for supplying heat energy or heat energy of steam generated in the waste heat recovery unit to the ammonia fuel supply unit.

[0010] Preferably, the gas turbine is a dual-fuel gas turbine that selectively uses ammonia and liquefied gas as fuel, and the ammonia gas turbine fuel supply system may further include a gas fuel supply unit for vaporizing liquefied gas stored in a liquid state and supplying it as fuel for the gas turbine.

[0011] Preferably, the gas fuel supply unit may include a liquefied gas storage tank that stores the liquefied gas in a liquid state; and a gas fuel compressor that compresses the evaporated gas of the liquefied gas generated by natural vaporization of the liquefied gas in the liquefied gas storage tank and supplies the evaporated gas to the gas turbine.

[0012] Preferably, it may include a cold heat recovery device for cooling the ammonia by heat exchange with the ammonia and the evaporated gas of the liquefied gas supplied to the gas fuel compressor and recovering it to the ammonia storage tank.

[0013] Preferably, the system further includes a generator engine that receives gas fuel from the gas fuel supply unit and generates electric power, and the generator engine can generate electric power equivalent to a load exceeding the output of the gas turbine.

[0014] Preferably, the gas turbine can generate power using the gas fuel as fuel when the load is less than the first load, and can generate power using at least one of the ammonia and the gas fuel as fuel when the load is greater than the first load and less than the second load.

[0015] Preferably, the heat source supply unit can supply heat energy from the waste heat recovery unit to the ammonia fuel supply unit when the gas turbine operates to generate electricity, and can supply heat energy of the steam to the ammonia supply unit when the gas turbine does not operate and only the generator engine is used to generate electricity.

[0016] Preferably, when the amount of liquefied gas vaporization gas generated by natural vaporization of the liquefied gas is greater than the amount that can be consumed by the gas turbine and generator engine, the system may further include a boiler that generates steam by burning the liquefied gas vaporization gas.

[0017] Preferably, the ammonia condenser may include an ammonia compressor that compresses the ammonia evaporation gas; an ammonia condenser that condenses the ammonia evaporation gas compressed in the ammonia compressor; and an ammonia re-liquefaction line that recovers the liquid ammonia condensed in the ammonia condenser to an ammonia storage tank.

[0018] Preferably, the waste heat recovery unit may include a waste heat recovery device that recovers waste heat of the exhaust gas to generate supercritical carbon dioxide; a supercritical turbine that expands the supercritical carbon dioxide generated in the waste heat recovery device to generate electricity; a recuperator that recovers residual heat of the carbon dioxide expanded in the supercritical turbine; and a supercritical compressor that compresses the carbon dioxide from which the residual heat has been recovered to a supercritical pressure and supplies the compressed carbon dioxide to the waste heat recovery device.

[0019] Preferably, the heat medium circulation line may further include a heat medium circulation line that sends carbon dioxide, from which residual heat has been recovered in the above-mentioned recuperator, to an ammonia fuel supply unit.

[0020] Preferably, the method may further include a heat recovery cooler that recovers the residual heat of carbon dioxide recovered from the recuperator by heat-exchanging it with a heat medium circulating through the heat source supply unit; and a heat source supply line that sends the heat medium heated in the heat recovery cooler to the ammonia fuel supply unit.

[0021] According to another aspect of the present invention for achieving the above-described purpose, a ship is provided, including the ammonia gas turbine fuel supply system.

[0022] In addition, according to another aspect of the present invention for achieving the above-described object, there is provided a method for generating gaseous ammonia, comprising: a step of vaporizing and heating ammonia stored in a liquid state to generate gaseous ammonia; a step of generating electric power by driving a gas turbine by combusting the gaseous ammonia and using the generated electric power as propulsion energy; a step of generating electric power by recovering waste heat of exhaust gas discharged from the gas turbine while circulating supercritical carbon dioxide; a step of condensing and recovering ammonia boil-off gas generated by natural vaporization of the ammonia stored in a liquid state instead of supplying it to the gas turbine; a step of recovering residual heat of the supercritical carbon dioxide or thermal energy of steam and supplying it to the step of generating gaseous ammonia; a step of purging at least one of a pipe through which the gaseous ammonia is supplied to the gas turbine and a pipe through which the ammonia boil-off gas is condensed and recovered when the mode in which the gas turbine is supplied with gaseous ammonia as fuel is stopped; A method for supplying ammonia gas turbine fuel to a ship is provided, further comprising a step of absorbing ammonia in the purging gas generated in the purging step.

[0023] Preferably, the gaseous ammonia supplied to the gas turbine can be entirely combusted in the gas turbine without any amount being recovered or discharged from the gas turbine.

[0024] Preferably, the method further includes a step of supplying the vaporized gas generated by natural vaporization of liquefied gas to the gas turbine as fuel; and the gas turbine can selectively use the gaseous ammonia and the vaporized gas, individually or in combination, as fuel to generate electricity.

[0025] The ammonia gas turbine fuel supply system and method for a vessel according to the present invention can store ammonia, an environmentally friendly fuel, in a liquid state and supply it to the engine in a gaseous state for use as fuel. Furthermore, when applied to vessels, the use of ammonia as fuel can reduce greenhouse gas emissions during operation and help meet regulatory standards set forth in international agreements.

[0026] Additionally, by generating electricity using a gas turbine that includes a combustor that burns ammonia, methane slip does not occur, so there is no need to release methane into the atmosphere, and carbon-free power generation is possible because carbon-containing fossil fuels are not used.

[0027] Additionally, the waste heat from the exhaust gas of the gas turbine can be recovered to vaporize liquid ammonia and other liquid gaseous fuels, thereby improving overall energy efficiency.

[0028] Additionally, since the gas turbine's gas valve unit is located within an enclosure, the risk of ammonia leakage is low.

[0029] In addition, by generating electricity using a gas turbine, nitrogen oxide emission regulations can be satisfied even when using ammonia as fuel, and since there is no need to install nitrogen oxide reduction devices such as selective catalytic reduction devices, space utilization can be increased and operating costs can be reduced.

[0030] In addition, the ammonia gas turbine fuel supply system and method of a ship according to the present invention is easily compatible with liquefied gases having similar properties to ammonia, such as methanol or LPG, and can be easily applied and used in engines other than gas turbines.

[0031] FIG. 1 is a schematic diagram illustrating an ammonia gas turbine fuel supply system according to embodiments of the present invention.

[0032] FIG. 2 is a schematic diagram illustrating an ammonia gas turbine fuel supply system including an ammonia fuel supply unit, an ammonia condenser unit, and an ammonia treatment unit according to one embodiment of the present invention.

[0033] FIG. 3 is a drawing for explaining the configuration of a gas turbine according to embodiments of the present invention.

[0034] FIG. 4 is a schematic diagram illustrating an ammonia fuel supply unit according to embodiments of the present invention.

[0035] FIG. 5 is a schematic diagram illustrating an ammonia condenser according to embodiments of the present invention.

[0036] FIG. 6 is a drawing for explaining a method for preventing leakage of a cold heat recovery device according to one embodiment of the present invention.

[0037] Figure 7 is a schematic diagram illustrating an ammonia treatment unit according to embodiments of the present invention.

[0038] Figure 8 is a schematic diagram illustrating a modified example of an ammonia treatment unit according to embodiments of the present invention.

[0039] FIG. 9 is a drawing for explaining one embodiment of a method for arranging a clean drain tank according to one embodiment of the present invention.

[0040] Figure 10 is a schematic diagram illustrating another embodiment of the ammonia treatment unit of the present invention.

[0041] Figure 11 is a schematic diagram illustrating another embodiment of the ammonia treatment unit of the present invention.

[0042] FIG. 12 is a schematic diagram illustrating a waste heat recovery unit according to one embodiment of the present invention.

[0043] FIG. 13 is a schematic diagram illustrating a modified example of a waste heat recovery unit according to one embodiment of the present invention.

[0044] Figure 14 is a schematic diagram illustrating an embodiment of supplying a heat source to an ammonia vaporizer according to the present invention.

[0045] FIG. 15 is a drawing for explaining a method of supplying thermal energy of steam as a heat source of an ammonia vaporizer using a heat source supply unit according to one embodiment of the present invention.

[0046] FIG. 16 is a drawing for explaining a method of supplying heat energy of a waste heat recovery unit as a heat source of an ammonia vaporizer using a heat source supply unit according to one embodiment of the present invention.

[0047] Figure 17 is a schematic diagram illustrating a gas fuel supply unit and a re-liquefaction unit according to one embodiment of the present invention.

[0048] Figure 18 is a drawing for explaining one embodiment of supplying a heat source from a waste heat recovery unit of the present invention to a fuel vaporizer.

[0049] FIG. 19 is a drawing for explaining another embodiment of supplying a heat source from a waste heat recovery unit to a fuel vaporizer according to one embodiment of the present invention.

[0050] FIG. 20 is a drawing illustrating a gas fuel compressor (720) and an evaporation gas compressor (810) in more detail according to one embodiment of the present invention.

[0051] FIG. 21 is a drawing for explaining a purging method of a gas turbine according to one embodiment of the present invention.

[0052] FIG. 22 is a drawing for explaining a purging method of a gas turbine according to one embodiment of the present invention.

[0053] Figure 23 is a cross-sectional view illustrating one embodiment of a ship arrangement configuration according to the present invention.

[0054] Fig. 24 is a plan view illustrating one embodiment of the ship arrangement configuration shown in Fig. 23.

[0055] Figure 25 is a cross-sectional view illustrating another embodiment of a ship arrangement configuration according to the present invention.

[0056] Fig. 26 is a plan view illustrating one embodiment of the ship arrangement configuration shown in Fig. 25.

[0057] To fully understand the operational advantages of the present invention and the objectives achieved by the embodiments of the present invention, reference should be made to the accompanying drawings, which illustrate preferred embodiments of the present invention, and the contents described therein. Even if the attached drawings are not directly referenced, if a person skilled in the art can clearly understand the operating principle based solely on the contents depicted in the drawings, the invention is considered to be described in this specification.

[0058] Hereinafter, the configuration and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Here, when adding reference numerals to components in each drawing, it should be noted that, as much as possible, identical components are indicated with the same numerals even if they are shown in different drawings. In addition, the following embodiments may be modified in various other forms, and the scope of the present invention is not limited to the following embodiments.

[0059]

[0060] The ammonia gas turbine fuel supply system and method according to embodiments of the present invention described below can be applied to a ship or land equipped with an ammonia storage tank that stores ammonia in a liquid state and an engine that can use ammonia as fuel, alone or in combination with other fuels.

[0061] Here, the term "engine" may refer to an internal combustion engine such as a two-stroke or four-stroke cycle engine, as well as equipment such as a fuel cell or turbine-generator that generates propulsion power for a ship or the electricity necessary to operate a ship by burning gaseous ammonia alone or mixed with other gaseous fuels.

[0062] In explaining the embodiments of the present invention described below, the engine is an ammonia gas turbine that generates power by driving a turbine with combustion gas generated by burning gaseous ammonia or gaseous fuel mixed with gaseous ammonia.

[0063] In addition, the ships here may include not only propulsion ships with propulsion capabilities, such as container ships and liquefied gas carriers, but also floating offshore structures that do not have propulsion capabilities but can use electricity produced using ammonia as fuel on board, such as FPSO (Floated Production, Storage and Offloading).

[0064] In addition, a liquefied gas carrier may be a hydrocarbon liquefied gas carrier such as liquefied natural gas (LNG), liquefied petroleum gas (LPG), or methanol (CH3OH), or a non-hydrocarbon liquefied gas carrier such as ammonia (NH3), hydrogen (H2), or carbon dioxide (CO2).

[0065] In the embodiments of the present invention described below, an example will be described in which the ship is an LNG carrier equipped with a cargo hold for storing LNG and transporting LNG.

[0066] In addition, in the embodiments of the present invention described below, the fuel is explained using ammonia as an example, but it can also be applied to fuels that have chemical properties similar to ammonia and can replace ammonia, such as methanol (CH3OH) and liquefied petroleum gas (LPG).

[0067] In summary, in the embodiments of the present invention described below, the ship is an electric propulsion gas turbine LNG carrier equipped with a gas turbine that uses ammonia as fuel as a carbon-free propulsion system, and the LNG carrier is a large-scale carrier of the 174,000㎥ class, as an example.

[0068]

[0069] Hereinafter, an ammonia gas turbine fuel supply system and method for a ship according to embodiments of the present invention will be described with reference to FIGS. 1 to 26.

[0070] First, referring to FIG. 1, an ammonia gas turbine fuel supply system according to embodiments of the present invention may include at least one of an engine that uses gaseous ammonia as fuel, an ammonia fuel supply unit (100) that supplies ammonia fuel to the engine, a heat source supply unit (300) that supplies a heat source for vaporizing liquid ammonia into gaseous ammonia to the ammonia fuel supply unit (100), a waste heat recovery unit (200) that recovers waste heat of exhaust gas from the engine and supplies it to the ammonia fuel supply unit (100) to vaporize liquid ammonia, an ammonia condenser (400) that condenses and recovers ammonia evaporation gas generated by natural vaporization of liquid ammonia, and an ammonia treatment unit (500) that processes ammonia in a purging gas generated while purging the ammonia gas turbine fuel supply system.

[0071] In explaining the embodiments of the present invention described below, the ammonia gas turbine fuel supply system of a ship is explained based on the case where it includes an ammonia fuel supply unit (100), a waste heat recovery unit (200), a heat source supply unit (300), an ammonia condensation unit (400), and an ammonia treatment unit (500), as shown in FIG. 1.

[0072] However, it is not limited thereto, and as shown in FIG. 2, it may be provided by selectively combining the ammonia fuel supply unit (100), the ammonia condenser unit (400), and the ammonia treatment unit (500), such as including only the ammonia fuel supply unit (100), the ammonia condenser unit (400), and the ammonia treatment unit (500).

[0073]

[0074]

[0075] Gas Turbine (GT)

[0076] An engine according to embodiments of the present invention may include a gas turbine (GT) that generates rotational force by using exhaust gas generated by combusting ammonia in the atmosphere and generates electric power using the rotational force.

[0077] Electricity generated by a gas turbine (GT) can be used for onboard power demand. When the ammonia gas turbine fuel supply system according to embodiments of the present invention is applied to a ship, the gas turbine (GT) can be used for electric propulsion of the ship and to generate the power required for onboard power demand.

[0078] A gas turbine (GT) may be a dual-fuel gas turbine that can use exhaust gas generated by burning other gaseous fuels, such as natural gas, in addition to ammonia as a working fluid.

[0079] That is, a gas turbine (GT) uses exhaust gas generated by combusting gaseous fuel as a working fluid, wherein the gaseous fuel may be at least one of gaseous ammonia, a mixed gas containing gaseous ammonia, or a gaseous gaseous fuel other than ammonia.

[0080] Therefore, the gas turbine (GT) can be selectively operated in one of the following modes depending on the situation: a mode using gaseous ammonia as fuel, a mode using a mixed gas containing gaseous ammonia as fuel, and a mode using another gaseous fuel as fuel.

[0081] Let's take the example of a dual-fuel gas turbine (GT) that uses gaseous ammonia as fuel, but uses natural gas as another gaseous fuel.

[0082] If the gas turbine (GT) is a dual-fuel gas turbine, ammonia and natural gas can be used as fuel, either individually or in combination, thereby reducing the emission of air pollutants and flexibly controlling the operating mode of the gas turbine (GT) for power generation.

[0083] A gas turbine (GT) initially operates in a mode that uses natural gas as fuel from the time of startup, and when the operating load reaches or exceeds the minimum load, it can be switched to a mode that uses ammonia or mixed gas as fuel.

[0084] Additionally, gas turbines (GTs) can generate electricity from loads above the minimum load, and can operate in an idling mode where they do not generate electricity but only drive the turbine by consuming fuel below the minimum load.

[0085] The no-load operation of the gas turbine (GT) can serve to pre-operate the gas turbine (GT) until the load of the gas turbine (GT) reaches the minimum load or higher, and can also serve to burn the gas to be incinerated on board.

[0086]

[0087] Meanwhile, conventional main propulsion engines that use ammonia and natural gas as fuel, following a four-stroke or two-stroke cycle, require pilot oil to burn the fuel. In addition, NO in the exhaust gas after combustion x Because of the high emissions, a Selective Catalytic Reduction (SCR) device was installed to meet emission regulations.

[0088] However, according to embodiments of the present invention, ammonia, a carbon-free fuel, is supplied as a gaseous phase to a gas turbine (GT) instead of an internal combustion engine for power generation of an electric propulsion ship, and is combusted in the combustion chamber of the gas turbine (GT), so pilot oil is not required, and CO2, NO x It may not produce any air pollutants at all. It also emits almost no nitrous oxide, which has the greatest greenhouse effect.

[0089] Therefore, even if ammonia and natural gas are burned, NO in the exhaust gas x Since it emits below the regulatory level, it can satisfy the emission regulations of the International Maritime Organization (IMO) without having to install nitrogen oxide reduction equipment such as SCR, which can increase space utilization and reduce operating costs as it does not require substances required for catalytic reaction such as urea water.

[0090]

[0091] Referring to FIG. 3, a gas turbine (GT) may be equipped with a combustion air inlet duct (CI) for inhaling combustion air necessary for combusting gaseous ammonia, and an exhaust duct (CO) for discharging combustion gas generated after combustion.

[0092] In addition, an air compressor (not shown) that generates compressed air by compressing combustion air sucked in through a combustion air intake duct (CI), a burner (not shown) that combusts fuel to generate exhaust gas, a combustion chamber (not shown) that is provided with an ammonia nozzle into which ammonia fuel is injected and a gas fuel nozzle into which natural gas is injected, in which a combustion reaction of the fuel occurs to generate combustion gas, a turbine (NH3gas turbine F&G system) (T) that uses the combustion gas (exhaust gas) discharged from the combustion chamber as a working fluid to rotate blades, and a generator (G) that generates electric power with the rotational force of the turbine (T) can be shielded and placed within an enclosure (EC).

[0093] In addition, auxiliary equipment essential for the operation of the gas turbine (GT) can be placed inside the enclosure (EC).

[0094] Combustion air compressed by an air compressor is supplied to the combustion chamber and used to combust ammonia or natural gas. When compressing combustion air using an air compressor, foreign substances can reduce turbine efficiency. Therefore, a combustion air inlet filter (CF) may be installed in the combustion air intake duct (CI) to filter out foreign substances such as yellow dust contained in the intake air.

[0095]

[0096] A gas valve unit or gas valve train including an ammonia purging valve (double block bleed valve) (AG) for preventing leakage of ammonia fuel supplied to a gas turbine (GT) through an ammonia supply line (FL) described later from an ammonia fuel supply unit (100) and a gas valve unit or gas valve train including a gas fuel purging valve (not shown) for preventing leakage of natural gas supplied from a gas fuel supply unit (700) described later are arranged in a pipe extending into an enclosure (EC) and sealed within the enclosure (EC).

[0097] The ammonia purging valve (AG) is installed in the ammonia supply line (FL) and is provided to block the supply of ammonia gas to the gas turbine (GT) when operation is stopped to ensure safety in accordance with international and classification regulations.

[0098] The ammonia purging valve (AG) consists of two double-blocking valves installed in series to isolate the front and rear ends, and a bleed valve installed between the double-blocking valves to naturally discharge (vent) the fluid between the double-blocking valves.

[0099] According to embodiments of the present invention, since the gas valve unit for ammonia and the gas valve unit for gas fuel are arranged within an enclosure (EC), environmental problems or safety problems that may arise due to leakage of ammonia or natural gas can be prevented.

[0100] The gas fuel valve unit installed in the gas fuel supply line (GL) for supplying natural gas as fuel to a gas turbine (GT) may be configured in two units for emergency situations. If one gas fuel valve unit experiences a problem, the other gas fuel valve unit can be used as an auxiliary valve to continuously supply natural gas to the gas turbine (GT) without stopping operation.

[0101] On the other hand, only one ammonia gas valve unit may be provided in the ammonia supply line (FL) for supplying ammonia as fuel to the gas turbine (GT), and no auxiliary valve may be provided.

[0102] That is, according to embodiments of the present invention, when a problem occurs in the ammonia gas turbine fuel supply system and the gas turbine (GT) cannot be operated in a mode using ammonia as fuel, the operation mode of the gas turbine (GT) can be automatically changed to a mode using natural gas as fuel and operated.

[0103]

[0104] Meanwhile, the ammonia supply line (FL) and the gas fuel supply line (GL) extending outside the enclosure (EC) may be provided with double-wall pipes to prevent fuel leakage. In the drawing, the portion provided with double-wall pipes is indicated with double lines (solid lines and double-dotted lines surrounding the solid lines). The portion provided with double-wall pipes may be from the downstream of the ammonia main supply valve (160) to the inlet of the enclosure (EC), and from the downstream of the gas fuel main supply valve (750) to the inlet of the enclosure (EC).

[0105]

[0106] Gas turbines (GTs) use toxic gaseous ammonia as fuel, and can also use liquefied gases such as LNG, which are explosive, as fuel. Therefore, the interior of the enclosure (EC) may be designed to satisfy a certain level of ventilation capacity using fans according to classification regulations.

[0107] A gas turbine (GT) may further be provided with a ventilation air inlet duct (VI) for sucking in ventilation air and a ventilation air outlet duct (VO) for exhausting ventilation air as a forced ventilation device, and a ventilation fan (FN) for transporting air may be provided in the ventilation air outlet duct (VO).

[0108] A ventilation air inlet filter (VF) may be installed in the ventilation air intake duct (VI) to filter out foreign substances such as yellow dust contained in the intake air.

[0109] Additionally, a sufficient number of gas detection sensors (not shown) are installed inside the enclosure (EC) to detect gas leaks. If a gas detection sensor detects a gas leak inside the enclosure (EC), the ventilation fan (FN) is stopped for the crew's evacuation, the fire damper is shut off (not shown), and visual / audible alarms (flash lamp and horn) are activated for 30 seconds.

[0110] When a gas leak is detected and the inside of the gas turbine (GT) and enclosure (EC) is ventilated, the ventilation air (⑨) discharged through the ventilation fan (FN) can be discharged into the atmosphere after the ammonia concentration is adjusted in the ammonia treatment unit (500) described below.

[0111]

[0112] Meanwhile, the classification society stipulates that when the forced ventilation devices lose their ventilation capacity or a leak occurs from the double-structure pipe, the ammonia master supply valve (160) and the gas fuel master supply valve (750) described later are to be closed.

[0113] When the ammonia main supply valve (160) or the gas fuel main supply valve (750) is closed, compressed air compressed by an air compressor can be supplied from the rear end of the ammonia purging valve or the gas fuel purging valve (double block valve or double block bleed valve) to the gas turbine (GT) for purging.

[0114] At this time, in order to supply compressed air for purging as illustrated in Fig. 22, a compressed air purging line (PGL, PGLf, PFLa) connected to the rear end of each purging valve (AGf, AGa) provided in a line (ammonia supply line (FL) or gas fuel supply line (GL)) for purging from an air compressor of a gas turbine (GT) and a compressed air purging valve (PGVf, PGVa) arranged on the compressed air purging line may be provided.

[0115] Additionally, purging can be performed using nitrogen generated on board from the front end of the ammonia purging valve (AGa) to the ammonia main supply valve (160).

[0116] The purging gas (① to ⑨) may be discharged through the ammonia treatment unit (500) described later, or may be discharged to the outside through the combustion gas discharge unit (CO) of the gas turbine (GT).

[0117] In addition, regardless of whether ammonia, natural gas, or mixed gas is used as fuel, the classification society and international regulations stipulate that in an emergency situation, the double block valve among the ammonia purging valve (double block and bleed valve) (AGa) and the gas fuel purging valve (AGf) must be closed.

[0118] The gas remaining between the double shut-off valves of the ammonia purging valve (AGa) is naturally vented through the bleed valve of the ammonia purging valve, and the vented ammonia can be discharged through the ammonia treatment unit (500) according to the classification regulations.

[0119]

[0120]

[0121] Ammonia fuel supply unit (100)

[0122] Referring to FIG. 4, an ammonia fuel supply unit (100) according to embodiments of the present invention may include at least one of an ammonia storage tank (110) for storing ammonia in a liquid state, an ammonia pressurizing pump (140) for pressurizing liquid ammonia transferred from the ammonia storage tank (110) so that gaseous ammonia supplied from the ammonia fuel supply unit (100) to the gas turbine (GT) can satisfy gaseous fuel pressure conditions required by the gas turbine (GT), and an ammonia vaporizer (150) for vaporizing ammonia pressurized by the ammonia pressurizing pump (140) to generate gaseous ammonia.

[0123]

[0124] An ammonia storage tank (ammonia fuel tank) (110) can store ammonia in a liquid state. Generally, ammonia is easier to store in a liquid state than in a gaseous state because it has a smaller volume. Therefore, gaseous fuel is stored in a liquefied state.

[0125] In addition, the ammonia storage tank (110) is an independent non-pressurized tank, and is described as an IMO Type A tank as an example. The ammonia storage tank (110) can be set to have an operating pressure at the atmospheric pressure level and an operating temperature at about -30 to -35°C or about -33°C so that ammonia can be stably stored while maintaining a liquid state.

[0126]

[0127] When the ammonia gas turbine fuel supply system according to embodiments of the present invention is applied to a ship, the ship stores ammonia in a liquid state, vaporizes the ammonia stored in the liquid state to generate gaseous ammonia fuel, combusts the gaseous ammonia in a combustion chamber of a gas turbine (GT) to generate combustion gas, and uses the combustion gas as a working fluid to drive the gas turbine (GT), thereby generating electric power that can be used as propulsion power for the ship.

[0128] The ammonia fuel supply unit (100) according to embodiments of the present invention is designed to supply ammonia according to the required pressure and temperature of a gas turbine (GT).

[0129] A gas turbine (GT) requires a gas fuel supply pressure of approximately 30 to 40 bar, or 32 to 36 bar, or approximately 34 bar. Here, the gas fuel supply pressure of a gas turbine (GT) of 34 bar will be used as an example for explanation.

[0130] Therefore, the ammonia fuel supply unit (100) according to embodiments of the present invention can produce gaseous ammonia gas fuel at the gas fuel supply pressure of a gas turbine (GT), i.e., about 34 bar.

[0131]

[0132] An ammonia boosting pump (140) can pressurize liquid ammonia transferred from an ammonia storage tank (110) so that gaseous ammonia generated by vaporization in an ammonia vaporizer (150) at the rear end can satisfy the fuel supply conditions of a gas turbine (GT).

[0133] The ammonia pressurizing pump (140) according to embodiments of the present invention can pressurize liquid ammonia to 30 to 40 bar, or 32 to 36 bar, or about 34 bar.

[0134] Considering the pressure loss that may occur during the process of transporting ammonia from the rear end of the ammonia pressurizing pump (140) to the front end of the gas turbine (GT), the discharge pressure of the ammonia pressurizing pump (140) may be set to a pressure slightly higher than the introduction pressure of the gas fuel required by the gas turbine (GT).

[0135] FIG. 4 illustrates an example in which two ammonia pressurizing pumps (140) are installed in parallel for redundancy. In this case, one ammonia pressurizing pump (140) is used to pressurize ammonia, while the other ammonia pressurizing pump (140) can be placed in an operation standby state so that the fuel supply system can continue to operate without interruption even if the ammonia pressurizing pump (140) in use has a problem and cannot be used. Alternatively, in cases where the ammonia flow rate required by the gas turbine (GT) is large, both ammonia pressurizing pumps (140) can be used to pressurize ammonia.

[0136] The ammonia pressurized pump (140) can be provided with a VFD (variable frequency drive) to have a speed control function for controlling the discharge flow rate of ammonia.

[0137]

[0138] Meanwhile, the ammonia gas turbine fuel supply system according to embodiments of the present invention may further include at least one of an ammonia supply pump (120) for discharging liquid ammonia stored in the ammonia storage tank (110) from the ammonia storage tank (110), and a buffer tank (130) for storing liquid ammonia discharged from the ammonia storage tank (110) by the ammonia supply pump (120) before supplying it to the ammonia pressurizing pump (140) to prepare for load fluctuations.

[0139] The ammonia feed pump (120) may be a semi-submersible pump installed on the bottom of the ammonia storage tank (110).

[0140] In Fig. 4, two ammonia supply pumps (120) are provided as an example. In this case, one of the two ammonia supply pumps (120) may be used as a redundancy for the other ammonia supply pump (120), or both ammonia supply pumps (120) may be used to discharge ammonia from the ammonia storage tank (110).

[0141] Liquid ammonia discharged by the ammonia supply pump (120) may be supplied to the ammonia pressurizing pump (140), or may be first stored in the buffer tank (130) and then supplied to the ammonia pressurizing pump (140) from the buffer tank (130) through the ammonia supply line (FL).

[0142] The operation of the ammonia supply pump (120) can be controlled according to the liquid level measurement value of the buffer tank (130).

[0143]

[0144] The buffer tank (130) stores a certain amount of liquid ammonia transported by the ammonia supply pump (120) and supplies the stored ammonia to the ammonia pressurizing pump (140), thereby preventing gaseous ammonia from flowing into the ammonia pressurizing pump (140) and causing problems in the operation of the ammonia pressurizing pump (140).

[0145] The ammonia in the gas phase that flows into the buffer tank (130) or the ammonia in the gas phase that is generated within the buffer tank (130) can be re-liquefied through the ammonia condenser (400) and recovered into the ammonia storage tank (110).

[0146] In addition, by providing a buffer tank (130), it is possible to ensure that liquid ammonia is stably supplied to the suction portion of the ammonia pressurizing pump (140) while maintaining a constant flow. Even if the load of the ammonia pressurizing pump (140) fluctuates, the flow rate of ammonia flowing into the ammonia pressurizing pump (140) from the buffer tank (130) can be adjusted, thereby also playing a role in buffering load fluctuations.

[0147] For example, if the flow rate of ammonia required by the gas turbine (GT) is less than the minimum flow rate of the ammonia pressurizing pump (140), the ammonia pressurizing pump (140) may be operated at the minimum flow rate, but the flow rate exceeding the ammonia flow rate required by the gas turbine (GT) may be circulated back to the buffer tank (130).

[0148] A buffer tank (130) may be equipped with a level gauge (not shown). The operation of the ammonia pressurized pump (140) may be controlled based on the liquid level measured by the level gauge. When the liquid level of the buffer tank (130) exceeds a preset value, the ammonia pressurized pump (140) is operated and liquid ammonia may flow from the buffer tank (130) into the ammonia pressurized pump (140).

[0149] In addition, the operation of the ammonia supply pump (120) can also be controlled according to the liquid level measured by the level gauge of the buffer tank (130). If the liquid level of the buffer tank (130) is lower than a preset value, the ammonia supply pump (120) can be operated to transfer ammonia stored in the ammonia storage tank (110) to the buffer tank (130). If the liquid level of the buffer tank (130) is higher than a preset value, the ammonia supply pump (120) can be controlled to automatically stop operation.

[0150] In the past, buffer tanks were used to temporarily store excess liquid fuel supplied to the engine by recovering it, and the conventional buffer tank controlled the operation of the pressurizing pump that supplied fuel to the engine according to changes in the engine load.

[0151] However, since the buffer tank (130) according to embodiments of the present invention does not supply and discharge ammonia according to the load of the gas turbine (GT), but its capacity is selected as a means to alleviate load fluctuations, the water level of the buffer tank (130) must be controlled so that it is filled to a preset value or higher.

[0152] If the ammonia pressure required by the gas turbine (GT) can be satisfied with only the ammonia supply pump (120), the system can be simplified without the ammonia pressurization pump (140) and the buffer tank (130). In this case, the liquid ammonia discharged from the ammonia storage tank (110) by the ammonia supply pump (120) can be supplied directly to the ammonia vaporizer (150) without passing through the buffer tank (130).

[0153] In explaining embodiments of the present invention, it will be explained based on the case having an ammonia supply pump (120), a buffer tank (130), and an ammonia pressurizing pump (140).

[0154]

[0155] An ammonia vaporizer (HP (high pressure) vaporizer) (150) vaporizes liquid ammonia pressurized by an ammonia pressurization pump (140) to produce gaseous ammonia. The gaseous ammonia vaporized in the ammonia vaporizer (150) can be introduced into a combustion chamber of a gas turbine (GT).

[0156] Meanwhile, in order to prevent ammonia from condensing during the process of being supplied from the ammonia fuel supply unit (100) to the gas turbine (GT), the ammonia vaporizer (150) may also have the role of heating the ammonia to a temperature higher than the dew point at the corresponding pressure.

[0157] For example, the introduction pressure of gaseous ammonia fuel required in a gas turbine (GT) according to embodiments of the present invention is about 34 bar, and at this pressure, the dew point of ammonia is about 80°C. To ensure that gaseous ammonia is introduced into the gas turbine (GT), the ammonia vaporizer (150) may change the phase of pressurized liquid ammonia into gaseous ammonia, thereby causing the temperature of the gaseous ammonia to be about 95 to 105°C, which is about 15 to 25°C higher than the dew point, or about 90 to 100°C, which is 10 to 20°C higher.

[0158] In the ammonia vaporizer (150), the pressure change of ammonia during phase change and heating may be negligible or may be negligible.

[0159] A temperature measuring device (not shown) may be provided downstream of the ammonia vaporizer (150) to measure the temperature of gaseous ammonia flowing into the gas turbine (GT) from the ammonia vaporizer (150). If the temperature measured by the temperature measuring device does not meet the temperature required by the gas turbine (GT), the ammonia discharged from the ammonia vaporizer (150) may be recycled back to the buffer tank (130).

[0160]

[0161] In addition, the ammonia fuel supply unit (100) may further include an ammonia supply line (FL) that extends from an ammonia supply pump (120) to a combustion chamber of a gas turbine (GT) and is equipped with at least one of a buffer tank (130), an ammonia pressurizing pump (140), and an ammonia vaporizer (150).

[0162] The ammonia supply line (FL) can be kept filled with liquid or gaseous ammonia at all times, except in emergency situations. If the gas turbine (GT) requires ammonia supply, gaseous ammonia can be supplied to the GT through the ammonia supply line (FL) at any time.

[0163] The ammonia fuel supply unit (100) is described based on the case where it includes an ammonia supply pump (120), a buffer tank (130), an ammonia pressurizing pump (140), and an ammonia vaporizer (150). In this case, the ammonia supply pump (120), the buffer tank (130), the ammonia pressurizing pump (140), and the ammonia vaporizer (150) can be sequentially arranged in the ammonia supply line (FL).

[0164] Liquid ammonia stored in an ammonia storage tank (110) can be discharged by an ammonia supply pump (120) and introduced into a combustion chamber of a gas turbine (GT) through a buffer tank (130), an ammonia pressurizing pump (140), and an ammonia vaporizer (150) along an ammonia supply line (FL).

[0165] The ammonia supply line (FL) consists of one line, and if the ammonia supply line (FL) becomes inoperable for any reason, it is impossible to use ammonia gas as fuel for the gas turbine (GT), so the gas turbine (GT) can be operated by switching to a mode that uses gas fuel, i.e., natural gas, as fuel according to the present embodiments.

[0166] An ammonia flow rate control valve (not given in the drawing) may be provided in the ammonia supply line (FL) to control the flow rate of gaseous ammonia supplied from the ammonia fuel supply unit (100) to the gas turbine (GT) so that an appropriate amount of gaseous ammonia can be supplied to the gas turbine (GT).

[0167]

[0168] An ammonia master gas valve (160) may be provided in the ammonia supply line (FL) between the ammonia vaporizer (150) and the gas turbine (GT) to control whether gaseous ammonia is supplied from the ammonia vaporizer (150) to the gas turbine (GT) or the supply is cut off.

[0169] Upstream of the ammonia main supply valve (160), at least one of the above-described temperature measuring device and a pressure measuring device (not shown) for measuring the pressure of gaseous ammonia may be provided.

[0170] When the temperature of gaseous ammonia measured by the temperature measuring device satisfies the supply temperature required by the gas turbine (GT) and the pressure of gaseous ammonia measured by the pressure measuring device satisfies the supply pressure required by the gas turbine (GT), the ammonia main supply valve (160) is opened so that gaseous ammonia can be supplied to the combustion chamber of the gas turbine (GT).

[0171]

[0172] Through the ammonia fuel supply unit (100), the ammonia supplied to the gas turbine (GT) is completely combusted. That is, in the embodiments of the present invention, there is no excess ammonia discharged from the gas turbine (GT).

[0173] Accordingly, the ammonia gas turbine fuel supply system according to embodiments of the present invention is not equipped with recovery equipment such as a return line or a pipe for recovering excess ammonia or ammonia slip back to the ammonia fuel supply unit (100), or a recovery buffer tank for receiving recovered ammonia so as to maintain the pressure of the system.

[0174] If there is excess ammonia or ammonia slip discharged from a gas turbine (GT), a recovery buffer tank and a separate recovery line are required, making the system configuration and control complicated. However, embodiments of the present invention have the effect of eliminating all of these configurations.

[0175] If the engine is a liquid-fuel engine, ammonia is supplied to the engine in a liquid state, which is an incompressible fluid. At this time, in order to flexibly respond to engine load fluctuations and to prevent cavitation in the pressurizing pump (booster pump), an excess amount of liquid fuel must be supplied to the engine, exceeding the flow rate required by the engine. It is desirable that only the amount of excess liquid fuel supplied to the engine be injected into the cylinders as required by the engine, and the remaining liquid fuel be recirculated back into the engine.

[0176] If the engine is supplied with gaseous ammonia as fuel, such as a gas turbine, there is no need to supply excess fuel to the engine, so a pressurization pump and a recirculation line for recirculating excess fuel from the engine are not required.

[0177]

[0178]

[0179] <Operating method of ammonia fuel supply unit (100)>

[0180] When supplying gaseous ammonia using a gas turbine (GT), an ammonia supply pump (120) provided in an ammonia storage tank (110) is operated to transfer ammonia to a buffer tank (130).

[0181] When the ammonia liquid level in the buffer tank (130) exceeds a certain level, the ammonia pressurizing pump (140) is operated to pressurize the ammonia and transfer it to the ammonia vaporizer (150).

[0182] In the ammonia vaporizer (150), ammonia is heated to the temperature required by the gas turbine and supplied to the gas turbine (GT).

[0183] The temperature is measured at the rear end of the ammonia vaporizer (150), and if it does not reach the temperature required by the gas turbine (GT), it is circulated to the buffer tank (130). When the temperature at the rear end of the ammonia vaporizer (150) reaches the supply temperature and pressure required by the gas turbine (GT), the ammonia main supply valve (160) opens and ammonia gas is supplied to the gas turbine (GT).

[0184]

[0185] It operates according to the liquid level of the buffer tank (130), and when the liquid level of the buffer tank (130) is below a certain level, it operates to transfer ammonia from the ammonia storage tank (110) to the buffer tank (130), and when the liquid level is above a certain level, the ammonia supply pump (120) automatically stops operating.

[0186] Ammonia transferred to the buffer tank (130) is pressurized in a liquid state by an ammonia pressurizing pump (140), and then passes through an ammonia vaporizer (150) to supply gaseous ammonia to a gas turbine (GT).

[0187] In the ammonia vaporizer (150), ammonia can be heated to a temperature of about 100°C, which is about 15 to 20°C higher than the dew point, and supplied to the gas turbine to prevent condensation of ammonia in the gas turbine and to combust it.

[0188] The ammonia gas naturally vaporized in the ammonia storage tank (110) is liquefied through the ammonia condenser (400) and re-stored in the ammonia storage tank (110), thereby controlling the pressure of the ammonia storage tank (110).

[0189] By using the flow rate control valve (FVa) among the gas valve units for ammonia provided inside the enclosure (EC) of the gas turbine (GT), the amount of gaseous ammonia required by the gas turbine (GT) is supplied to the combustion chamber of the gas turbine (GT), and ammonia is supplied from the ammonia pressurizing pump (140) to the ammonia vaporizer (150) in a corresponding amount. At this time, the control of the ammonia pressurizing pump (140) may be performed according to the flow rate or pressure of ammonia introduced into the gas turbine (GT).

[0190]

[0191]

[0192] <Ammonia condensing system (400)>

[0193] Referring to FIG. 5, an ammonia condenser (400) according to embodiments of the present invention may be provided as a means for re-liquefying naturally vaporized ammonia (ammonia vaporization gas) generated by naturally vaporizing liquid ammonia stored in an ammonia storage tank (110) and returning it to the ammonia storage tank (110).

[0194] The ammonia condenser (400) may include an ammonia compressor (410) that compresses ammonia evaporation gas discharged from an ammonia storage tank (110) through an ammonia evaporation gas line (BL), and an ammonia condenser (420) that condenses the evaporation gas compressed by the ammonia compressor (410) to produce re-liquefied ammonia.

[0195] The ammonia compressor (410) can compress ammonia vapor gas to 16 to 18 bar.

[0196] Ammonia evaporation gas compressed in the ammonia compressor (410) can be cooled to about 50°C in an aftercooler (not given a drawing symbol) provided downstream of the ammonia compressor (410).

[0197] The ammonia compressor (410) of the present embodiment may be an oil-free three-stage reciprocating compressor. Or, it may be an oil-injected screw compressor.

[0198]

[0199] The cooling source for condensing the ammonia evaporation gas in the ammonia condenser (420) may be fresh water or seawater provided within the system.

[0200] In the ammonia condenser (420), the ammonia evaporation gas can be condensed while being cooled to about 40°C.

[0201] The condensed evaporated gas, i.e., liquid ammonia, in the ammonia condenser (420) can be recovered to the ammonia storage tank (110) along the ammonia reliquefaction line (RL).

[0202]

[0203] Meanwhile, the ammonia condenser (400) may further include a receiver (430) that receives ammonia evaporation gas cooled by heat exchange with a cooling source in the ammonia condenser (420).

[0204] Even if all of the ammonia evaporation gas is condensed through heat exchange with the cooling source in the ammonia condenser (420), there is a possibility that some of it may vaporize during the transport process. In addition, if the amount of ammonia evaporation gas is large or cooling energy is insufficient, only a portion of the ammonia evaporation gas may be condensed, and uncondensed ammonia evaporation gas may exist.

[0205] According to embodiments of the present invention, by receiving ammonia discharged from an ammonia condenser (420) in a receiver (430) before supplying it to an ammonia storage tank (110), only liquid ammonia can be supplied from the receiver (430) to the ammonia storage tank (110).

[0206] The uncondensed ammonia vapor separated from the receiver (430), i.e., gaseous ammonia, can be recycled to the ammonia compressor (410), and in case of an emergency, it can be sent to the vent mast (VM2) and released into the atmosphere for disposal.

[0207] By re-liquefying the gaseous ammonia generated by natural vaporization of liquid ammonia in the ammonia storage tank (110) and recovering the liquid re-liquefied ammonia from the receiver (430) to the ammonia storage tank (110), the pressure and temperature of the ammonia storage tank (110) can be maintained within the operating pressure and operating temperature ranges.

[0208] The internal pressure of the receiver (430) can be controlled by a valve (not given a drawing symbol) provided downstream of the receiver (430).

[0209]

[0210] Meanwhile, in the case where the ammonia gas turbine fuel supply system according to embodiments of the present invention further includes a gas fuel supply unit (700) and a re-liquefaction unit (800) described below, the ammonia condensation unit (400) may further include a cold heat recovery device (440) that recovers cold heat of LNG boil-off gas transferred from the LNG storage tank (600) to the gas fuel supply unit (700) or the re-liquefaction unit (800).

[0211] A tank cooling line (CL) branching from an ammonia supply line (FL) connecting an ammonia supply pump (120) and a buffer tank (130) and connected to a cold heat recovery device (440) is further included, so that at least a portion of the liquid ammonia supplied to the buffer tank (130) by the ammonia supply pump (120) can be supplied to the cold heat recovery device (440).

[0212] For example, if the temperature of the ammonia storage tank (110) is too high, the temperature of the ammonia storage tank (110) can be lowered by heat-exchanging the liquid ammonia discharged by the ammonia supply pump (120) with the LNG evaporation gas to cool the liquid ammonia and then returning it to the ammonia storage tank (110).

[0213] The cooled ammonia re-supplied to the ammonia storage tank (110) through the tank cooling line (CL) can be supplied by spraying from the top of the ammonia storage tank (110) in a supercooled state.

[0214] In addition, if the cold heat of the LNG boil-off gas is not recovered in the re-liquefaction device (830) described later, the cold heat can be recovered by supplying the LNG boil-off gas to the cold heat recovery device (440).

[0215]

[0216]

[0217] <LNG 증발가스냉열을활용한 암모니아 저장탱크 냉각 및 가스연료공급부로의암모니아 누출 방지>

[0218] In a vessel according to embodiments of the present invention, as described above, the ammonia evaporation gas generated from the ammonia stored in the ammonia storage tank (110) is re-liquefied through the ammonia condenser (400) and returned to the ammonia storage tank (110), thereby controlling the internal pressure of the ammonia storage tank (110).

[0219] A cold heat recovery device (440) utilizing the cold heat of LNG evaporation gas can be used to cool and control the internal pressure of the ammonia storage tank (110).

[0220] To this end, a tank cooling line (CL) is provided to cool the ammonia transferred from the ammonia storage tank using the LNG evaporation gas cooling heat and then return it to the ammonia storage tank using the ammonia supply pump (120) provided to transfer ammonia from the ammonia storage tank (110) to the ammonia fuel supply unit (100).

[0221] A cold heat recovery device (440) is provided in the tank cooling line (CL) to cool ammonia by heat exchange with LNG evaporation gas generated in the LNG storage tank.

[0222] Ammonia pumped from the ammonia supply pump (120) can be recovered to the ammonia storage tank (110) in a sub-cooled state by exchanging heat with LNG evaporation gas through the cold heat recovery device (440).

[0223] LNG boil-off gas generated in an LNG storage tank (600) is transferred to a gas fuel supply unit (700) after recovering cold heat from a cold heat recovery device (440) through a gas fuel supply line (GL). If a re-liquefaction unit (800) is in operation to re-liquefy surplus LNG boil-off gas, the cold heat of LNG boil-off gas generated in the LNG storage tank (600) is recovered first through a re-liquefaction device (830), and then passed through a cold heat recovery device (440) to recover cold heat secondarily and then transferred to a gas fuel supply unit (700).

[0224] Supercooled ammonia that has passed through the cold heat recovery device (440) can be sprayed onto the upper portion of the ammonia storage tank (110). By spraying the supercooled ammonia in this way to cool the upper portion of the ammonia storage tank, the temperature at the upper portion of the tank can be lowered, thereby reducing the generation of ammonia evaporation gas and controlling the pressure inside the tank. Ammonia that has been re-liquefied through the ammonia condenser (400) and recovered into the ammonia storage tank can also be sprayed onto the upper portion of the ammonia storage tank to cool the upper portion of the tank.

[0225] In this way, by controlling the temperature and pressure of the ammonia storage tank through the cold heat recovery device (440) and the tank cooling line (CL), the operation of the ammonia condenser can be reduced, thereby reducing the driving power and the use of seawater or fresh water for cooling. Furthermore, if the pressure of the ammonia storage tank can be controlled without re-liquefying the ammonia evaporation gas through the cold heat recovery device and the tank cooling line, a method of reducing CAPEX without installing the ammonia condenser (400) can also be considered.

[0226] Meanwhile, even when the ammonia storage tank (110) and the LNG storage tank (600) are set to similar operating pressures at the atmospheric pressure level, ammonia is pumped and transported from the ammonia storage tank through the ammonia supply pump (120), and the LNG boil-off gas is naturally generated and discharged from the LNG storage tank. Therefore, the ammonia flow has a relatively higher operating pressure than the LNG boil-off gas flow when passing through the cold heat recovery device (440). Therefore, if a hole or damage occurs in the heat exchanger-type cold heat recovery device, ammonia may leak toward the LNG boil-off gas flow. If the leaked ammonia flows into the gas fuel supply unit (700) through the gas fuel supply line (GL), it may lead to damage to the pipes and devices, failure, etc.

[0227] To prevent this, a device can be configured to detect ammonia leakage and discharge ammonia when a leakage is detected, thereby allowing for proper discharge.

[0228] Figure 6 illustrates an ammonia cooling system according to a modified example in which a device capable of detecting and discharging ammonia leakage from a cold heat recovery device is additionally configured.

[0229] As illustrated in FIG. 6, the ammonia cooling system according to the present embodiment includes a gas receiver (450) provided in a gas fuel supply line (GL) to receive LNG evaporation gas that has passed through a cold heat recovery device, and an ammonia detection unit (470) to detect the presence or absence of ammonia inside the gas receiver.

[0230] A non-return valve (490) is provided at the front end of the gas receiver in the gas fuel supply line (GL), and an emergency stop valve (ESD valve) (460) is provided at the rear end of the gas receiver in the gas fuel supply line.

[0231] In addition, when ammonia is detected in the ammonia detection unit (470), an ammonia discharge line (DL) is provided to discharge ammonia from the gas receiver (450), and an ammonia discharge valve (480) is provided in the ammonia discharge line.

[0232] The LNG evaporation gas that has passed through the cold heat recovery device (440) and gas receiver (450) via the gas fuel supply line (GL) is transferred to the gas fuel supply unit (700) and supplied as fuel for a gas turbine, etc.

[0233] When ammonia is detected in the gas receiver (450), the emergency stop valve (460) is immediately controlled to close by the ammonia detection unit (470), thereby preventing ammonia from flowing into the gas fuel supply unit (700) from the gas receiver. The ammonia detection unit (470) opens the ammonia discharge valve (480) to discharge the remaining ammonia in the gas fuel supply line (GL) from the cold heat recovery device (440) to the gas receiver (450) through the ammonia discharge line (DL).

[0234] Ammonia discharged through the ammonia discharge line can be transferred to and processed in an ammonia treatment unit (500) provided on board to control the ammonia concentration of the purging gas containing ammonia.

[0235] As discussed above, this embodiment utilizes the cold energy from the LNG boil-off gas to cool the ammonia storage tank, thereby controlling the internal pressure of the ammonia storage tank, thereby reducing the power consumption required to operate the ammonia condenser. Furthermore, even if a puncture or damage occurs in the cold energy recovery device, the risk of ammonia flowing into the LNG boil-off gas due to operating pressure differences, leading to damage to piping and equipment, or failure, can be reduced.

[0236]

[0237]

[0238] <Purging method>

[0239] When performing maintenance on an ammonia gas turbine fuel supply system according to embodiments of the present invention, or when the operation mode for operating ammonia is interrupted, such as when a problem occurs while the gas turbine (GT) is operating in a mode using ammonia as fuel or when operation must be switched to a mode using natural gas as fuel, the pipes or equipment through which ammonia flows must be purged before resuming operation.

[0240] For the purpose of performing purging, a purging supply unit is provided for supplying purging fluid upstream or downstream of equipment requiring purging, and a purging discharge unit is provided for discharging purging gas discharged while purging ammonia remaining in the pipe or equipment.

[0241] In explaining embodiments of the present invention, nitrogen is used as an example as a purging fluid, but the same can be applied even if another inert gas or compressed air compressed in the above-described air compressor is used instead of nitrogen.

[0242]

[0243] The purging supply unit may be equipped with a purging valve (not shown) for supplying purging fluid to each line in a specific situation, i.e., a situation where purging must be performed.

[0244] When purging is to be performed, the system operation is stopped, the valves are closed to isolate each purging point, and then nitrogen or compressed air compressed from a gas turbine (GT) air compressor is supplied to the purging supply section of the point requiring purging. The nitrogen or compressed air supplied to the purging supply section flows through the pipes and equipment, generating purging gas together with the remaining ammonia, which can then be discharged through the purging discharge section.

[0245] In particular, the line connecting the rear end of the purging valve to the gas turbine when switching fuel of the gas turbine (GT) must be purged.

[0246] When purging is performed, the purging valve of the line requiring purging is opened, compressed air is supplied to the rear of the purging valve, and the remaining gas is blown out into the combustion chamber using the compressed air and combusted together.

[0247] Purging gas containing the purged fuel from the rear end of the purging valve to the gas turbine (GT) can be used together as fuel for the gas turbine (GT), resulting in fuel savings.

[0248] In general, when purging natural gas, it is known that the natural gas is released into the atmosphere as is and the global warming impact is 28 times that of CO2 (ICCT report, 100 years without Climate Carbon FeedBack), and when natural gas is burned and released, the impact is 2.75 times that of CO2 (MEPC.308(73), Conversion factor between fuel consumption and CO2 emission).

[0249] Therefore, it has been shown that emitting natural gas as it is has an environmental impact that is about 10 times greater than emitting it by combustion. However, according to embodiments of the present invention, the environmental impact can be reduced by also emitting the purged gas by combustion.

[0250] In the case of an ammonia supply line (FL), the purging gas must be discharged by lowering the concentration of ammonia to a certain level or lower using an ammonia treatment unit (500), but according to embodiments of the present invention, the purging gas can be treated by combustion in a gas turbine (GT), so it does not have to go through the ammonia treatment unit (500), and thus the capacity of the ammonia treatment unit (500) can be reduced and operating costs can also be reduced.

[0251] In addition, purging using compressed air can reduce the amount of N2 consumed during purging with N2, thereby reducing the operating costs required for N2 production. The purging method from the rear end of the purging valve using compressed air to the gas turbine (GT) is described below.

[0252]

[0253] Here, the mixture of nitrogen or compressed air and ammonia discharged together with ammonia is called purging gas.

[0254] In the attached drawings, nitrogen supplied to the purging supply section is indicated as N2, and the purging gas discharged from the purging exhaust section is indicated with circle letters ①, ②, ③, ④, ⑤, ⑥, ⑦, ⑧, and ⑨, respectively.

[0255]

[0256] *When purging is performed, nitrogen can be supplied to each point of the ammonia fuel supply unit (100), for example, upstream of the ammonia pressurizing pump (140), and discharged to the downstream side, and nitrogen can be supplied to the upstream of the ammonia vaporizer (150) and discharged to the downstream side.

[0257] In addition, purging can also be performed on the ammonia condenser (400). At this time, nitrogen can be supplied to each point of the ammonia condenser (400), for example, upstream of the ammonia compressor (410), and discharged downstream of the ammonia condenser (420) and downstream of the receiver (430), i.e., to the line through which the gas phase is discharged from the receiver (430).

[0258] In explaining embodiments of the present invention, the purging gas may include at least one of a purging gas (①, ②) generated while purging an ammonia pressurizing pump (140) and an ammonia supply line (FL) connected upstream and downstream of the ammonia pressurizing pump (140), and a purging gas (③) generated while purging an ammonia vaporizer (150) and an ammonia supply line (FL) connected upstream and downstream of the ammonia vaporizer (150).

[0259] In addition, the purging gas may include at least one of the following: the purging gas (④) generated while purging the cold heat recovery device (440), the tank cooling line (CL) connected upstream and downstream of the cold heat recovery device (440), the purging gas (⑤) generated while purging the receiver (430), and the purging gas (⑥) generated while purging the ammonia evaporation gas line (BL) from the upstream of the ammonia condenser (420) and the ammonia compressor (410) to the downstream of the ammonia condenser (420).

[0260] In addition, the purging gas may include at least one of the following: purging gas (⑦) generated while purging between the double shut-off valves of the ammonia purging valve (AG), purging gas (⑧) generated while purging the double-structure pipe from the upstream of the ammonia purging valve (AG) to the downstream of the ammonia main supply valve (160), and purging gas (⑨) generated while purging or ventilating the inside of the gas turbine (GT) or the inside of the enclosure (EC).

[0261] Whether or not the purging gas, purging supply unit, and purging discharge unit described above are indicated in each drawing does not mean that the purging gas, purging supply unit, and purging discharge unit are included or excluded as essential components in applying the embodiments of the present invention, and may be appropriately omitted or indicated for the visibility of the drawing.

[0262]

[0263]

[0264] <Purging method using compressed air from a gas turbine>

[0265] As described above, in the case of fuel switching, maintenance, etc., purging is required to discharge the gas from the pipes through which fuel was supplied, among the gas fuel supply line (GL) and the ammonia supply line (FL) connected to the gas turbine, as shown in Fig. 21.

[0266] In the case of natural gas, there are no regulations on direct emissions, but in the case of ammonia gas, there are regulations prohibiting the emission of ammonia gas above a certain concentration. Therefore, in the case of ammonia operation, before stopping the gas turbine operation, the gas turbine is switched to natural gas fuel mode and operated with natural gas for a certain period of time before being stopped.

[0267] The air compressor, which compresses combustion air in a gas turbine to generate compressed air, continues to rotate for a certain period of time due to inertia even after the gas turbine has been shut down, generating compressed air. This compressed air can be used to effectively purge the line from the downstream end of the purging valve of the fuel supply pipe to the gas turbine, especially before fuel switching or shutdown. As mentioned above, nitrogen is supplied to the upstream end of the purging valve of each pipe to perform the purging.

[0268] As illustrated in Fig. 22, in order to supply compressed air and transport the fuel remaining between the gas turbine and the combustion chamber (GTC) from the downstream of the double shut-off valve (AGf or AGa) of the corresponding pipe, a first compressed air purging line (PGLf) is connected from an air compressor (GTP) to a downstream of a gas fuel purging valve (AGf) provided in a gas fuel supply line (GL), and a second compressed air purging line (PGLa) is connected from an air compressor (GTP) to a downstream of an ammonia purging valve (AGa) provided in an ammonia supply line (FL). A first compressed air purging valve (PGVf) is provided in the first compressed air purging line, and a second compressed air purging valve (PGVa) is provided in the second compressed air purging line.

[0269] When switching fuel in a gas turbine, the double shut-off valve of the pipe through which the fuel was supplied before switching is closed, the compressed air purging valve provided in the line connected to the pipe among the first and second compressed air purging lines is opened to supply compressed air to the pipe through which the fuel was supplied before switching, and the fuel remaining between the gas turbine and the downstream side of the double shut-off valve of the pipe is transferred to the combustion chamber (GTC) and combusted before being discharged as exhaust gas.

[0270] In particular, when switching from ammonia fuel mode, which is subject to direct emission regulations, to natural gas fuel mode, or when switching to natural gas fuel mode for a certain period of time to stop the gas turbine while operating in ammonia fuel mode, the ammonia supply line can be purged in this way, and the ammonia fuel remaining in the pipe can be burned together in the gas turbine to be discharged as exhaust gas. In addition, the natural gas remaining in the pipe can also be processed as fuel in the gas turbine by burning it in the combustion chamber of the gas turbine. In this way, according to the present embodiment, by combusting and utilizing the fuel gas discarded during purging in the gas turbine, the amount of fuel used can be reduced, toxic gases can be effectively processed, and the impact on the environment can be reduced and emission regulations can be met.

[0271]

[0272]

[0273] Ammonia catching system (500)

[0274] Referring to FIG. 7, the ammonia treatment unit (500) according to embodiments of the present invention may be provided as a means for controlling the ammonia concentration in the purging gas (① to ⑨) generated while purging ammonia remaining in at least one of the ammonia fuel supply unit (100) and the ammonia condenser unit (400) when the operation of the gas turbine (GT) is stopped while the operation is being performed in a mode using ammonia as fuel or a mode using a mixed gas as fuel.

[0275] Except for ammonia released in emergency situations, the concentration of ammonia released into the atmosphere is limited by classification regulations. To ensure compliance with the limited concentration, an ammonia treatment unit (500) may be provided.

[0276] The purging gas generated while purging at least one of the ammonia fuel supply unit (100) and the ammonia condenser unit (400) is a mixture of nitrogen and ammonia supplied for purging, and after passing through the ammonia treatment unit (500) to adjust the ammonia concentration, can be released into the atmosphere through the vent mast (VM2).

[0277] The ammonia treatment unit (500) can be operated when the gas turbine (GT) is operated in a mode using ammonia as fuel or a mode using mixed gas as fuel, and then trips, stops operation, or switches to a mode using natural gas as fuel.

[0278] Except for the gas released into the atmosphere through the emergency vent mast (VM1) in an emergency situation specified by the classification society, all gas containing ammonia discharged from the ammonia gas turbine fuel supply system can be discharged into the atmosphere through the operating vent mast (VM2) after the ammonia concentration has been adjusted through the ammonia treatment unit (500).

[0279]

[0280] The ammonia treatment unit (500) may include a separator (510) for separating gas and liquid from the purging gas (① to ⑨) generated during purging, and an absorber (520) for separating ammonia from the gas components separated in the separator (510).

[0281] The liquid component separated in the separator (510) is liquid ammonia transferred from a gas turbine (GT), an ammonia fuel supply unit (100) or an ammonia condenser unit (400), or liquid ammonia condensed during the process of being transferred together with nitrogen.

[0282] Liquid ammonia separated in the separator (510) can be recovered in the ammonia storage tank (110) and used again as fuel.

[0283] Additionally, the gas component separated in the separator (510) may be a mixed gas of nitrogen and gaseous ammonia supplied for purging.

[0284] The gas component separated in the separator (510) is supplied to the absorber (520), where ammonia in the mixed gas is captured, and the remaining gas after capturing the ammonia, i.e., nitrogen-rich gas, satisfies exhaust gas emission regulations and can be released into the atmosphere through the vent mast (VM2).

[0285]

[0286] The absorber (520) may be equipped with a water (make-up water) replenishment unit (not shown) that supplies water as a solvent for capturing ammonia in the mixed gas.

[0287] Here, a water tank (not shown) for storing absorption water to be supplied to the absorber (520) is further provided, and absorption water can be supplied to the absorber (520) from the water tank.

[0288] In describing embodiments of the present invention, the water for absorption may be seawater or technical water.

[0289] The mixed gas supplied to the absorber (520) exchanges materials with the water supplied to the absorber (520), so that the gaseous ammonia in the mixed gas is dissolved in the water.

[0290] Water containing dissolved ammonia can be discharged to the bottom of the absorber (520).

[0291] The remaining residual gas components from which ammonia has been removed through material exchange with water in the absorber (520) can be transported to the vent mast (VM2) through the upper part of the absorber (520) as nitrogen or nitrogen-rich gas containing a small amount of ammonia.

[0292]

[0293] The water in which ammonia is dissolved, discharged from the bottom of the absorber (520), is stored in the drain tank (530). By circulating the water stored in the drain tank (530) back to the absorber (520) using a water circulation pump (not given a drawing symbol), ammonia is further absorbed into the circulated water at the bottom of the absorber (520), so that ammonia is not discharged.

[0294] Additionally, during this process, water may be lost, or water may be supplied to the absorber (520) through a water replenishment unit to dissolve ammonia.

[0295] In addition, an acidity meter (not shown) for measuring the acidity of the drain tank (530) is further provided, so that when the measured acidity does not reach the set value, that is, when the pH rises above the set standard, water is supplied to the absorber (520) through a water replenishment unit, so that the acidity of the water recirculated from the drain tank (530) to the absorber (520) can be maintained.

[0296] In addition, when high-concentration ammonia dissolved water is generated as ammonia dissolved water accumulates in the drain tank (530), the high-concentration ammonia dissolved water may be transferred to a separate ammonia bilge tank (540) or may be discharged into the sea as is.

[0297] In the past, excess ammonia or slipped ammonia was inevitably discharged from the engine, and thus recovery lines or recovery equipment had to be included to recover it. Compared to conventional ammonia fuel supply systems, the ammonia gas turbine fuel supply system according to embodiments of the present invention does not have excess or slipped ammonia, and therefore the amount of ammonia contained in the purging gas flowing into the ammonia treatment unit (500) is relatively small.

[0298] Therefore, according to embodiments of the present invention, ammonia in the purging gas can be dissolved with only pure water without using a separate chemical solvent, thereby reducing the concentration of ammonia in the purging gas discharged into the atmosphere.

[0299]

[0300] Referring to FIG. 8, the ammonia treatment unit (500) may further include a supplementary water cooling device for cooling the supplementary water to be supplied to the absorber (520).

[0301] Ammonia interacts with water through hydrogen bonding, making it highly soluble at room temperature. Because hydrogen bonding is a type of weak electrostatic interaction, increasing water temperature increases the activity of water molecules, making it more difficult for ammonia molecules to bond with water molecules, and weakening the hydrogen bond.

[0302] Therefore, as the water temperature increases, the solubility of ammonia decreases, and as the water temperature decreases, the solubility of ammonia increases. When the water temperature decreases from approximately 36°C to 5°C, the solubility of ammonia more than doubles.

[0303] The supplementary water cooling device is a means for increasing the solubility of ammonia in water, and by using the supplementary water cooling device, the temperature of the water supplied to the absorber (520) can be kept low.

[0304] The supplementary water cooling device can be applied when an ammonia gas turbine fuel supply system according to embodiments of the present invention is installed in a ship.

[0305] Typically, ships have cabin areas (Q) for crew work and rest, and air conditioning units (QC) are installed in cabin areas (Q) to control the temperature within the cabin areas (Q). The air conditioning unit (QC) is a device that transfers the cold heat of the refrigerant into the cabin areas (Q) as water circulates through the refrigerant cycle. As the water circulates through the refrigerant cycle, it condenses to produce low-temperature clean drain water. Typically, the temperature of the clean drain water produced by the air conditioning unit (QC) is approximately 6 to 13°C when cooling is performed in the summer.

[0306] The supplementary water cooling device may include a clean drain water tank (550) that stores clean drain water, and a clean drain pump (570) that supplies water stored in the clean drain water tank (550) to an absorber (520).

[0307] The clean drain water tank (550) may be the water tank described above.

[0308] Since the temperature of clean drain water is 6 to 13°C, the solubility of ammonia can be increased compared to the case where clean water of about 36°C is supplied to the absorber (520).

[0309] In this embodiment, the low-temperature condensate generated by cooling indoor air in an air conditioning unit (QC) is stored in a clean drain water tank (550) as an example, but the present invention is not limited thereto, and any low-temperature fluid generated in a ship, such as cooling water, or low-temperature water can be applied. Here, low temperature can be less than 36°C, or 6 to 13°C, or 1 to 20°C.

[0310] In addition, the supplementary water cooling device may further include a drain temperature measuring unit (551) that measures the temperature of the clean drain tank (550) and a chiller (560) that cools the clean drain tank (550).

[0311] When the temperature of the clean drain tank (550) measured by the drain temperature measuring unit (551) becomes higher than the set value, the chiller (560) can be operated to cool the clean drain tank (550) to below the set value.

[0312] In this embodiment, the temperature setting value of the clean drain tank (550) may be 5 to 10°C.

[0313] In summer, the air conditioning unit (QC) operates in cooling mode, so the temperature of the clean drain water is sufficiently low. However, the temperature of the clean drain water generated in spring, fall, and winter is lower than the temperature of the clean drain water generated in summer. The chiller (560) of the present embodiment can be operated primarily in spring, fall, and winter.

[0314] Meanwhile, referring to FIG. 9, a clean drain tank (550) may be provided within a ballast tank (BT). The ballast tank (BT) is provided to maintain the balance of the hull by controlling the water level of seawater stored in the ballast tank (BT), and the temperature of the seawater stored in the ballast tank (BT) is approximately 0°C to 32°C.

[0315] Therefore, by installing the clean drain tank (550) inside the ballast tank (BT), the temperature stability of the clean drain tank (550) can be improved.

[0316]

[0317] Meanwhile, as another embodiment, referring to FIG. 10, an ammonia treatment unit (500) according to another embodiment of the present invention may further include a purging gas condensation line (PL) that sends the purging gas (① to ⑨) transferred to the ammonia treatment unit (500) to the ammonia condensation unit (400).

[0318] When the purging gas condensation line (PL) is opened, at least a portion of the purging gas (① to ⑨) can be transported upstream of the ammonia compressor (410) through the purging gas condensation line (PL) before being introduced into the absorber (520).

[0319] In this embodiment, the purging gas that can be supplied to the ammonia condenser (400) through the purging gas condensation line (PL) may include one or more of the above-described purging gases ①, ②, ③, ⑤, ⑦, and ⑧.

[0320] The purging gases (① to ③, ⑤, ⑦, ⑧) mentioned in this embodiment are all generated from downstream of the ammonia pressurization pump (140) or downstream of the ammonia compressor (410). That is, these purging gases (① to ③, ⑤, ⑦, ⑧) contain ammonia compressed to the pressure of the fuel required by the gas turbine (GT), i.e., approximately 34 to 37 barg.

[0321] When the purging gases (① to ③, ⑤, ⑦, ⑧) mentioned in this embodiment are supplied to the ammonia condenser (420) through the purging gas condensation line (PL) and the compression branch line (PL1) connected to bypass the ammonia compressor (410) and supplied to the ammonia condenser (420), the ammonia components in the purging gas can be condensed by heat exchange in the ammonia condenser (420).

[0322] When the pressure of compressed ammonia is lowered while being purged, the purging gases (① to ③, ⑤, ⑦, ⑧) may be supplied to the ammonia compressor (410) through the purging gas condensation line (PL), compressed, and then sent to the ammonia condenser (420).

[0323] In the ammonia compressor (410), the purging gas can be compressed to about 18 bar.

[0324] After heat exchange in the ammonia condenser (420), the purging gas in which the ammonia components are condensed is introduced into the receiver (430) through the ammonia evaporation gas line (BL).

[0325] In the receiver (430), the purging gas containing condensed ammonia components is separated into gas and liquid, so that the liquid ammonia can be recovered to the ammonia storage tank (110), and the remaining purging gas that is not condensed, i.e., the purging gas such as nitrogen or compressed air supplied for purging, can be recycled to the ammonia treatment unit (500) or released into the atmosphere through the vent mast (VM2).

[0326] According to this embodiment, there is an effect of recovering and reusing as much ammonia as possible in the purging gas.

[0327] However, in this embodiment, the purging gas (⑥) generated while purging the ammonia compressor (410), the ammonia condenser (420), and the ammonia evaporation gas line (BL) from the upstream of the ammonia compressor (410) to the downstream of the ammonia condenser (420) can be supplied downstream of the point where the purging gas condensation line (PL) branches off from the pipe through which the purging gas is supplied to the absorber (520) so as not to flow into the purging gas condensation line (PL).

[0328] That is, the purging gas ⑥ can be supplied directly to the separator (510) without being supplied to the ammonia condenser (400).

[0329]

[0330] In addition, as another embodiment, referring to FIG. 11, an ammonia treatment unit (500) according to another embodiment of the present invention may further include a solvent injection device (521) that injects a solvent capable of removing ammonia through a chemical reaction into the absorber (520) and into the scrubber.

[0331] If the ammonia concentration of the gas discharged from the absorber (520) does not decrease below a preset reference value for a certain period of time, a solvent capable of absorbing ammonia can be injected into the absorber (520) using a solvent injection device (521).

[0332] This embodiment can be applied to cases where purging gas containing a high concentration of ammonia must be processed, compared to the above embodiment in which water is injected into the absorber (520) to absorb ammonia.

[0333] In this embodiment, the purging gas may include one or more of the purging gases ① to ⑨ described above.

[0334] The solvent injection device (521) can be operated when the ammonia concentration of the gas discharged from the absorber (520) does not fall below a reference value for a certain period of time, even if the ammonia is dissolved in the absorber (520) using water.

[0335] The solvent injection device (521) can be used as a means for quickly controlling the ammonia concentration of gas discharged from the absorber (520) by injecting a solvent into the absorber (520) and causing a chemical reaction with ammonia.

[0336] According to this embodiment, it can be usefully used in cases where the concentration of ammonia in the purging gas is high, such as when ammonia leaks inside the enclosure (EC) of a gas turbine (GT).

[0337]

[0338]

[0339] <Waste heat recovery unit (sCO2power system) (200)>

[0340] Referring to FIG. 7, the waste heat recovery unit (200) is a closed-loop cycle that uses supercritical carbon dioxide (sCO2) as a working fluid, and recovers waste heat from the exhaust gas (combustion gas) of a gas turbine (GT), heats the carbon dioxide to generate supercritical carbon dioxide, and expands the supercritical carbon dioxide to generate electricity through expansion work, thereby generating additional electricity other than the electricity generated by the gas turbine (GT).

[0341] Compared to conventional steam generators, which generate electricity by driving a turbine using steam as the working fluid, using supercritical carbon dioxide as the working fluid reduces frictional losses compared to steam, thereby increasing power generation efficiency. Furthermore, its higher density compared to steam allows for a reduction in the volume of fluid used for the same mass.

[0342] The waste heat recovery unit (200) may include at least one of an exhaust gas line (EL) that discharges exhaust gas from a gas turbine (GT), a waste heat recovery device (main heater) (220) that recovers waste heat of the exhaust gas discharged through the exhaust gas line (EL) to generate supercritical carbon dioxide, a supercritical turbine (sCO2turbine) (230) that generates power by driving a turbine using the supercritical carbon dioxide generated in the waste heat recovery device (220) as a working fluid, and a supercritical compressor (sCO2compressor) (260) that compresses carbon dioxide expanded in the supercritical turbine (230) to generate supercritical carbon dioxide again.

[0343] It may further include a supercritical line (SL) that connects a waste heat recovery device (220), a supercritical turbine (230), and a supercritical compressor (260) to form a closed cycle.

[0344] The medium circulating in the supercritical line (SL) can be carbon dioxide. Carbon dioxide has a critical temperature of 31°C and a critical pressure of 73.8 bar. At atmospheric pressure and temperature (1 bar, 20°C), the densities of air and carbon dioxide are 1.29 kg / m2, respectively. 3 , 1.97kg / m 3 It has the characteristic of high density compared to compressed air. The efficiency of gas turbines (GT) can be improved by recovering waste heat from exhaust gas using high-density supercritical carbon dioxide as a medium.

[0345] Carbon dioxide can be circulated through a waste heat recovery device (220), a supercritical turbine (230), and a supercritical compressor (260) along a supercritical line (SL) and then back to the waste heat recovery device (220) in a repeating process.

[0346]

[0347] In a supercritical compressor (260), carbon dioxide can be compressed to a critical pressure of 73.8 bar or higher. The compressed carbon dioxide compressed in the supercritical compressor (260) has a high temperature and pressure.

[0348] In the waste heat recovery device (220), waste heat of exhaust gas discharged from a gas turbine (GT) through an exhaust gas line (EL) is recovered and carbon dioxide compressed in a supercritical compressor (260) is heated, thereby generating supercritical carbon dioxide.

[0349] Carbon dioxide that has passed through the supercritical compressor (260) and the waste heat recovery device (220) has pressure and temperature conditions that satisfy the supercritical conditions of carbon dioxide, and the supercritical carbon dioxide generated through the supercritical compressor (260) and the waste heat recovery device (220) can be supplied to the supercritical turbine (230).

[0350] The work generated when supercritical carbon dioxide is expanded by a supercritical turbine (230) can be converted into electricity to generate electricity, and the electricity generated by the supercritical turbine (230) can be supplied to an internal power demand source.

[0351]

[0352] In addition, the waste heat recovery unit (200) according to embodiments of the present invention may further include one or more of a preheater (210) provided on a supercritical line (SL) to further recover residual heat of exhaust gas from which waste heat has been recovered in a waste heat recovery device (220), a recuperator (240) to recover residual heat of carbon dioxide discharged after driving a supercritical turbine (230), and a precooler (250) to maintain a constant temperature of carbon dioxide introduced into a supercritical compressor (260).

[0353] In describing embodiments of the present invention, the description will be based on a case in which a preheater (210), a recuperator (240), and a precooler (250) are all included. If necessary, the residual heat of carbon dioxide may be recovered by using only one of the preheater (210), recuperator (240), and precooler (250).

[0354] In the preheater (210), residual heat of the exhaust gas from which waste heat has been recovered in the waste heat recovery device (220) can be further recovered to heat the compressed carbon dioxide supplied from the supercritical compressor (260) to the waste heat recovery device (220).

[0355] The exhaust gas cooled after heat exchange in the preheater (210) can be released into the atmosphere, and the heated compressed carbon dioxide can be introduced into the waste heat recovery device (220).

[0356]

[0357] In the recuperator (240), the expanded carbon dioxide that is discharged in an expanded state while driving the supercritical turbine (230) and supplied to the supercritical compressor (260) is heat-exchanged with the compressed carbon dioxide that is supplied from the supercritical compressor (260) to the waste heat recovery device (220), so that the compressed carbon dioxide can be heated with the residual heat of the expanded carbon dioxide.

[0358] The temperature of carbon dioxide heated by the residual heat of carbon dioxide in the recuperator (240) can be about 110°C.

[0359] The cooled expanded carbon dioxide after heat exchange in the recuperator (240) can be introduced into the supercritical compressor (260), and the heated compressed carbon dioxide can be introduced into the waste heat recovery device (220).

[0360] Either the preheater (210) or the recuperator (240) may be installed on the supercritical line (SL), and the other may be installed on the supercritical branch line (SL1) branched from the supercritical line (SL) connecting the supercritical compressor (260) and the waste heat recovery device (220).

[0361] That is, the compressed carbon dioxide compressed in the supercritical compressor (260) can be preheated in at least one of the preheater (210) and the recuperator (240) before being introduced into the waste heat recovery device (220).

[0362] In Fig. 12, a recuperator (240) is provided on a supercritical line (SL), and a preheater (210) is provided on a supercritical branch line (SL1) that branches off from the supercritical line (SL) connecting the supercritical compressor (260) and the recuperator (240) and joins the supercritical line (SL) connecting the recuperator (240) and the waste heat recovery device (220).

[0363] At this time, the compressed carbon dioxide supplied from the supercritical compressor (260) to the waste heat recovery device (220) may be preheated by either the preheater (210) or the recuperator (240), or the flow rate of the compressed carbon dioxide supplied to the preheater (210) and the flow rate of the compressed carbon dioxide supplied to the recuperator (240) may be adjusted so that some of the compressed carbon dioxide is preheated in the recuperator (240) and then supplied to the waste heat recovery device (220), and the remainder is preheated in the preheater (210) and then supplied to the waste heat recovery device (220).

[0364]

[0365] In the precooler (250), the expanded carbon dioxide transferred from the supercritical turbine (230) or the expanded carbon dioxide expanded in the supercritical turbine (230) and then recovered from the residual heat in the recuperator (240) is cooled by heat exchange between the refrigerant and the expanded carbon dioxide supplied to the supercritical compressor (260).

[0366] The temperature of the expanded carbon dioxide after the residual heat is recovered in the recuperator (240) is still high. In order to efficiently operate the waste heat recovery unit (200), a pre-cooler (250) is provided to further cool the expanded carbon dioxide and then supply it to the supercritical compressor (260).

[0367] In the pre-cooler (250), seawater or fresh water can be used as a refrigerant to cool carbon dioxide to approximately 37°C.

[0368] By providing a pre-cooler (250) to cool the expanded carbon dioxide supplied to the supercritical compressor (260), the compressor inlet temperature of the supercritical compressor (260) can be kept constant, while the compression efficiency for producing supercritical carbon dioxide is increased.

[0369]

[0370] Meanwhile, referring to FIG. 8, the waste heat recovery unit (200) according to embodiments of the present invention may further include a heat recovery cooler (HR (hot recovery) cooler) (270) provided downstream of the recuperator (240) to further recover residual heat of expanded carbon dioxide from which residual heat has been recovered in the recuperator (240).

[0371] The temperature of the expanded carbon dioxide before being cooled in the precooler (250) may still be too high to be compressed in the supercritical compressor (260) to produce supercritical carbon dioxide. Therefore, before being introduced into the supercritical compressor (260), at least one of the precooler (250) and the heat recovery cooler (270) may be provided to further utilize the residual heat of the expanded carbon dioxide expanded in the supercritical turbine (230).

[0372] According to embodiments of the present invention, the residual heat of the expanded carbon dioxide recovered in the heat recovery cooler (270) can be used in the ammonia fuel supply unit (100) or the gas fuel supply unit (700).

[0373]

[0374]

[0375] <Operating method of waste heat recovery unit (200)>

[0376] When the operation of the gas turbine (GT) is stabilized, the waste heat recovery unit (200) operates, and the waste heat of the exhaust gas discharged from the gas turbine (GT) can be recovered using the waste heat recovery unit (200).

[0377] The temperature of carbon dioxide from which residual heat has been recovered in the recuperator (240) may still be high enough to be compressed in the supercritical compressor (260) to produce supercritical carbon dioxide. Therefore, a heat recovery heater (270) is provided downstream of the recuperator (240) to further recover residual heat of carbon dioxide recycled to the supercritical compressor (260) and use it at a heat source demand location requiring heat energy.

[0378] A heat source demander that uses the residual heat of carbon dioxide recovered from a heat recovery cooler (270) may be an ammonia vaporizer (150).

[0379]

[0380] Hereinafter, with reference to FIGS. 13 and 14, examples of utilizing the residual heat of expanded carbon dioxide recovered from a heat recovery cooler (270) in an ammonia fuel supply unit (100) will be described.

[0381] First, as an example, referring to FIG. 13, a heat recovery cooler (270) and an ammonia vaporizer (150) are connected, and a heat medium circulation line (HL) through which a heat medium circulates is further provided, so that ammonia can be vaporized by indirectly utilizing the waste heat of carbon dioxide.

[0382] The heat medium is heated by heat exchange with expanded carbon dioxide in a heat recovery cooler (270), and then transferred to an ammonia vaporizer (150) through a heat medium circulation line (HL) and cooled by heat exchange with liquid ammonia, and a cycle can be formed in which the heat medium is circulated to the heat recovery cooler (270) through the heat medium circulation line (HL).

[0383] By using a heat medium to supply the waste heat of carbon dioxide as a heat source to vaporize ammonia, the carbon dioxide and ammonia do not come into direct contact, so the problem of mutual contamination can be prevented.

[0384]

[0385] As another embodiment, referring to FIG. 14, a heat source supply line (HL3) branching downstream of the recuperator (240) from the supercritical line (SL) and connected to the ammonia vaporizer (150) may be included.

[0386] That is, according to the embodiment illustrated in FIG. 14, the heat recovery cooler (270) described above may be an ammonia vaporizer (150).

[0387] Expanded carbon dioxide supplied from a supercritical turbine (230) or recuperator (240) to a precooler (250) or a supercritical compressor (260) through a supercritical line (SL) can be supplied to an ammonia vaporizer (150) through a heat source supply line (HL3) downstream of the supercritical turbine (230) or recuperator (240).

[0388] At this time, in the ammonia vaporizer (150), the carbon dioxide transferred through the heat source supply line (HL3) and the liquid ammonia transferred through the ammonia supply line (FL) exchange heat, so that the carbon dioxide is cooled and the liquid ammonia is vaporized and heated by the residual heat of the carbon dioxide.

[0389] Carbon dioxide cooled after heat exchange in the ammonia vaporizer (150) can be circulated to the supercritical compressor (260) or precooler (250) through a heat source supply line (HL3) connected from the ammonia vaporizer (150) to the supercritical line (SL) upstream of the supercritical compressor (260) or precooler (250).

[0390] The waste heat recovery unit (200) according to the embodiment illustrated in FIG. 14 may further include at least one of a heat source supply valve (280) provided in a heat source supply line (HL3) upstream of an ammonia vaporizer (150), and a heat source branch valve (290) provided in a supercritical line (SL) downstream of a point where the heat source supply line (HL3) branches off downstream of a recuperator (240) and upstream of a point where the heat source supply line (HL3) joins the supercritical line (SL).

[0391] The heat source supply valve (280) enables carbon dioxide to be supplied to the ammonia vaporizer (150) from downstream of the recuperator (240) by opening and closing control, and can adjust the flow rate of carbon dioxide supplied to the ammonia vaporizer (150) by opening amount control.

[0392] The heat source branch valve (290) can control the opening and closing so that carbon dioxide is not supplied to the ammonia vaporizer (150) but to the precooler (250) or the supercritical compressor (260) downstream of the recuperator (240), and can control the flow rate of carbon dioxide supplied to the precooler (250) or the supercritical compressor (260) by bypassing the ammonia vaporizer (150) by controlling the opening amount.

[0393] When the gas turbine (GT) is initially started and when the load is below a certain level, for example, below 60%, it can be operated in a mode using natural gas as fuel until the operation of the gas turbine (GT) is stabilized.

[0394] When the gas turbine (GT) is operated in a mode using natural gas as fuel, the ammonia vaporizer (150) does not operate, so the heat source supply valve (280) is controlled to be closed and the heat source branch valve (290) is controlled to be open, so that the carbon dioxide from which residual heat has been recovered in the recuperator (240) can bypass the ammonia vaporizer (150) and be cooled in the precooler (250).

[0395] When the gas turbine (GT) is changed to a mode that uses gaseous ammonia as fuel, ammonia must be supplied to the gas turbine (GT), so the heat source supply valve (280) is controlled to open gradually so that carbon dioxide is supplied to the ammonia vaporizer (150), and the heat source branch valve (290) is controlled to close gradually.

[0396] The heat source supply valve (280) and the heat source branch valve (290) can be organically controlled to control the flow rate of carbon dioxide supplied to the ammonia vaporizer (150) in order to supply the amount of heat required by the ammonia vaporizer (150).

[0397]

[0398] If the waste heat of the exhaust gas of a gas turbine (GT) recovered through a waste heat recovery unit (200) is used as a heat source for an ammonia vaporizer (150), not only can additional power be generated using the waste heat of the exhaust gas, but also ammonia can be vaporized, thereby greatly improving the efficiency of the gas turbine (GT).

[0399] The pressure of the liquid ammonia is compressed to about 30 to 40 barg by at least one of the ammonia supply pump (120) and the ammonia pressurizing pump (140), but the temperature is maintained at the temperature of the ammonia stored in the ammonia storage tank (110), i.e., about -30 to -35°C, or increased to a level slightly higher therefrom.

[0400] That is, in the ammonia vaporizer (150), liquid ammonia at about 30 to 40 barg and about -30 to -35°C must be heated to about 100°C, which is a temperature higher than the dew point, so the temperature change of ammonia required in the ammonia vaporizer (150) requires a large amount of heat, reaching about 130 to 135°C.

[0401] By recovering the waste heat of carbon dioxide circulating through the waste heat recovery unit (200) and utilizing it as heat energy to vaporize liquid ammonia in the ammonia vaporizer (150), the heating duty of the ammonia fuel supply unit (100) can be reduced.

[0402] Additionally, since conventional heat sources such as steam or electricity are not required to vaporize ammonia, the amount of fuel required to generate steam can be reduced, thereby reducing operating costs and reducing negative impacts on the environment.

[0403]

[0404]

[0405] <Hot water system (300)>

[0406] The heat source supply unit (300) according to embodiments of the present invention has a function of supplying the heat energy of carbon dioxide or steam circulating in the waste heat recovery unit (200) as a heat source to the ammonia vaporizer (150).

[0407] The heat source supply unit (300) may be configured as a cycle in which a heated heat medium is supplied to an ammonia vaporizer (150) as a heat source for vaporizing ammonia, and the cooled heat medium is heated by heat exchange with steam or carbon dioxide circulating in a waste heat recovery unit (200) while vaporizing liquid ammonia in the ammonia vaporizer (150), and then supplied to the ammonia vaporizer (150).

[0408] In explaining embodiments of the present invention, the heat medium circulating in the heat source supply unit (300) may be fresh water or technical water.

[0409] By using clean water or industrial water as a heat medium, even if ammonia leaks during the process of exchanging heat with ammonia in an ammonia vaporizer (150), the system can be operated safely because ammonia is a component that dissolves in water, and the problem of ammonia and carbon dioxide being mixed can be prevented.

[0410]

[0411] Referring to FIGS. 15 and 16, the heat source supply unit (300) according to embodiments of the present invention comprises a heat medium heater (HW (hot water) heater) (330) that heats the heat medium to be supplied to the ammonia vaporizer (150) by heat exchange with steam to generate a high-temperature heat medium, a heat medium circulation pump (HW circ. pump) (320) that pressurizes the low-temperature heat medium cooled by heat exchange in the ammonia vaporizer (150) and supplies it to the heat medium heater (330) or the heat recovery cooler (270), a heat medium tank (HW exp. tank) (310) for receiving the low-temperature heat medium discharged from the ammonia vaporizer (150) and supplying it to the heat medium circulation pump (320), and a heat medium supplement unit (make-up water) (not given a drawing symbol) that supplements the heat medium circulating in the heat source supply unit (300) to the heat medium tank (310). It can contain one or more.

[0412] The heat medium is heated by heat exchange with steam in the heat medium heater (330), cooled by heat exchange with liquid ammonia in the ammonia vaporizer (150), and then introduced into the heat medium circulation pump (320) through the heat medium tank (310), pressurized by the heat medium circulation pump (320), and can be circulated back to the heat medium heater (330).

[0413] The gaseous heat medium heated by heat exchange with steam in the heat medium heater (330) can be separated into gas and liquid in the heat medium tank (310) and vented into the atmosphere, and only the liquid heat medium can be introduced into the heat medium circulation pump (320) from the heat medium tank (310).

[0414]

[0415] If the temperature rises excessively during the process of circulating the heat medium, the temperature can be maintained by supplying supplemental water to the heat medium tank (310) through the heat medium replenishment unit.

[0416] The supplemental water may be technical water, which is generally lower in temperature than the heat medium circulating in the heat source supply unit (300) in embodiments of the present invention, and thus can lower the temperature of the heat medium.

[0417] The internal pressure of the heat medium tank (310) can be controlled to a preset pressure using a control valve (not shown) to prevent overpressure.

[0418]

[0419] According to embodiments of the present invention, a steam heating line (HL1) may be further included, which branches off from the heat medium circulation line (HL) downstream of the heat medium circulation pump (320), is connected to the heat medium heater (330), and joins the heat medium circulation line (HL) downstream of the heat recovery cooler (270) downstream of the heat medium heater (330).

[0420] That is, the liquid heat medium pressurized by the heat medium circulation pump (320) can be heated by the residual heat of carbon dioxide in the waste heat recovery unit (200) through the heat medium circulation line (HL) connected from the downstream of the heat medium circulation pump (320) to the upstream of the heat recovery cooler (270), depending on whether the waste heat recovery unit (200) is operating, or can be supplied to the heat medium heater (330) by bypassing the waste heat recovery unit (200) through the steam heating line (HL1) branching from the downstream of the heat medium circulation pump (320) to the heat medium heater (330), thereby being heated by steam and being supplied as a heat source for the ammonia vaporizer (150).

[0421] That is, the liquid heat medium pressurized by the heat medium circulation pump (320) can be selectively controlled to be heated by heat exchange with steam in the heat medium heater (330) or by heat exchange with carbon dioxide in the heat recovery cooler (270).

[0422] In addition, the liquid heat medium pressurized by the heat medium circulation pump (320) may be supplied to both the heat medium heater (330) and the heat recovery cooler (270), with some of the heat medium being supplied to the heat medium heater (330) and the remainder being supplied to the heat recovery cooler (270), and then combined downstream of the heat medium heater (330) and supplied to the ammonia vaporizer (150).

[0423] Additionally, if necessary, at least a portion of the liquid heat medium pressurized by the heat medium circulation pump (320) may be introduced into a steam bypass line (HL2) that is provided to bypass both the heat medium heater (330) and the heat recovery cooler (270) without heating.

[0424]

[0425] As described above, in the ammonia vaporizer (150), liquid ammonia can be vaporized using at least one of the heat energy of carbon dioxide supplied through the waste heat recovery unit (200), the heat energy of steam supplied through the heat source supply unit (300), and the heat energy supplied through the heat source supply unit (300) and the waste heat recovery unit (200).

[0426] The ammonia vaporizer (150) can receive a heat medium heated by the waste heat recovery unit (200) when the waste heat recovery unit (200) is in operation, and can receive a heat medium heated by steam when the waste heat recovery unit (200) is not in operation. Even when the waste heat recovery unit (200) is in operation, if the heat energy of carbon dioxide that can be recovered by the waste heat recovery unit (200) is insufficient, the ammonia vaporizer (150) can be supplied with a heat source by using the heat energy of carbon dioxide vapor in combination.

[0427] Referring to Fig. 15, when the waste heat recovery unit (200) is not in operation, the liquid heat medium pressurized by the heat medium circulation pump (320) is supplied to the heat medium heater (330) through the steam heating line (HL1), and after being heated by heat exchange with steam in the heat medium heater (330), it is joined to the heat medium circulation line (HL) through the steam heating line (HL1) and can be supplied to the ammonia vaporizer (150).

[0428] Referring to Fig. 16, when the waste heat recovery unit (200) is in operation, the liquid heat medium pressurized by the heat medium circulation pump (320) is supplied to the heat recovery cooler (270) through the heat medium circulation line (HL), and after being heated by the residual heat of carbon dioxide in the heat recovery cooler (270), it can be supplied to the ammonia vaporizer (150) through the heat medium circulation line (HL).

[0429]

[0430]

[0431] <Gas Fuel Supply Unit (700)>

[0432] Meanwhile, the gas turbine (GT) according to embodiments of the present invention can use other gaseous fuels as fuel in addition to ammonia, and the other gaseous fuel according to embodiments of the present invention can be natural gas.

[0433] Accordingly, the gas turbine fuel supply system according to embodiments of the present invention may further include a gas fuel supply unit (700) for supplying natural gas fuel to the gas turbine (GT).

[0434] Referring to FIG. 17, the gas fuel supply unit (700) according to embodiments of the present invention may further include at least one of an LNG storage tank (600) that stores natural gas in a liquid state, i.e., LNG, and a gas fuel compressor (720) that receives LNG boil-off gas (BOG) generated by natural vaporization of LNG stored in the LNG storage tank (600) and compresses it to satisfy pressure conditions required by a gas turbine (GT).

[0435] LNG boil-off gas generated in the LNG storage tank (600) can be supplied to the combustion chamber of the gas turbine (GT) through a gas fuel supply line (GL) connected from the LNG storage tank (600) to the gas turbine (GT).

[0436] A gas fuel supply line (GL) between a gas fuel compressor (720) and a gas turbine (GT) may be provided with a gas fuel main supply valve (750) to control whether LNG boil-off gas from the gas fuel compressor (720) is supplied to the gas turbine (GT) or the supply is cut off.

[0437]

[0438] Meanwhile, two gas fuel supply lines (GL) are installed in parallel, so that when one line is in a state of failure for some reason, gas fuel can be supplied to the gas turbine (GT) or generator engine (GE) using the other line, so that electric power propulsion can be operated without any problem.

[0439] When starting a gas turbine (GT), only natural gas can be used as fuel, and since the operating range is wider when using natural gas as fuel than when using ammonia, it is safe to install a spare gas fuel supply line (GL) to allow for natural gas operation.

[0440] In addition, the gas fuel supply line (GL) may be equipped with a gas fuel purging valve (double block bleed valve) (AGf in Fig. 21) to block the supply of natural gas fuel to the gas turbine (GT) or generator engine (GE) for safety purposes in accordance with international and classification regulations when the mode of supplying gas fuel is interrupted. One set of the gas fuel purging valve (AGf) may be installed per each gas fuel supply line (GL1, GL2) as illustrated in Figs. 21 and 22.

[0441] The gas fuel purging valve (AGf) consists of two double block valves installed in series to isolate the front and rear ends, and a bleed valve installed between the double block valves to naturally discharge (vent) the fluid between the double block valves.

[0442] In addition, the gas fuel supply line (GL) may be equipped with a gas fuel flow rate control valve (FVf in FIG. 21) that controls the flow rate of natural gas supplied from the gas fuel supply unit (700) to the gas turbine (GT) so that an appropriate amount of natural gas can be supplied to the gas turbine (GT). One set of gas fuel flow rate control valves may be installed per gas fuel supply line (GL).

[0443]

[0444] The LNG storage tank (600) may be a fuel tank that stores LNG as fuel. In addition, when the ammonia gas turbine fuel supply system according to embodiments of the present invention is applied to an LNG carrier, one or more LNG storage tanks (600) are provided, and may be cargo tanks that store LNG as cargo.

[0445] Fig. 17 illustrates an example in which four cargo tanks are provided as LNG storage tanks (600).

[0446]

[0447] The LNG boil-off gas compressed in the gas fuel compressor (720) can be supplied to the combustion chamber as fuel for a gas turbine (GT). The pressure conditions of natural gas required by the gas turbine (GT) may be the same as those of gaseous ammonia.

[0448] The gas fuel compressor (720) may be provided as a multi-stage compressor, and the number of stages of the multi-stage compressor may vary depending on the fuel supply pressure required by a consumer to which natural gas is supplied, such as a gas turbine.

[0449] In embodiments of the present invention, a multi-stage compressor is described as a three-stage compressor as an example. Natural gas compressed in the third stage can be compressed to a fuel supply pressure required by a gas turbine (GT), i.e., a pressure of about 30 to 40 bar, or about 36 barg in the present embodiment. The natural gas that has undergone three-stage compression is discharged at a pressure required by the gas turbine (GT) and supplied to the gas turbine (GT) through a gas fuel main supply valve (750).

[0450] The temperature of natural gas fuel required in a gas turbine (GT) may be about 30 to 40°C, or about 43 to 45°C.

[0451] For example, the temperature of the evaporated gas compressed at about 36 barg in the gas fuel compressor (720) is about 45°C.

[0452] During the process of being compressed in the gas fuel compressor (720), the temperature of the LNG evaporation gas rises, and it is discharged from the gas fuel compressor (720) and introduced into the gas turbine (GT) at a temperature of about 30 to 40°C.

[0453] On the other hand, natural gas compressed in the second stage can meet the fuel supply pressure required by the generator engine (GE) and boiler (Aux. Boiler) (BR), which have relatively low fuel supply pressure.

[0454] The gas fuel compressor (720) can serve to maintain the absolute pressure of the LNG storage tank (600) at a constant level or within a preset value.

[0455] When the absolute pressure of the LNG storage tank (600) increases or is about to reach a value higher than the set value, LNG boil-off gas is discharged from the LNG storage tank (600) through the gas fuel supply line (GL), and the discharged LNG boil-off gas can be supplied to the gas fuel compressor (720). The boil-off gas compressed in the gas fuel compressor (720) can be supplied as fuel to one or more of a gas turbine (GT), a generator engine (GE), and a boiler (BR).

[0456]

[0457] Meanwhile, when the gas turbine (GT) is stopped or is operated in a mode using ammonia as fuel, the gas fuel compressor (720) may not be operated, but considering energy efficiency, the natural gas compressor (720) may be operated to compress the LNG boil-off gas and supply it as fuel for the generator engine (GE) and boiler (BR).

[0458] Accordingly, the gas fuel supply unit (700) may further include a pressure reducing device (not given a drawing symbol) that reduces the pressure of the LNG evaporation gas compressed in the gas fuel compressor (720) to the fuel pressure required by the generator engine (GE) and boiler (BR) described below.

[0459] Natural gas depressurized in the depressurizer can be supplied as fuel for a generator engine (GE) or boiler (BR).

[0460]

[0461] In addition, the gas fuel supply unit (700) according to one embodiment of the present invention may further include a cold heat recovery device (440) that recovers cold heat of LNG evaporation gas supplied from the LNG storage tank (600) to the gas fuel compressor (720) and cools ammonia.

[0462] Ammonia cooled by heat exchange with LNG evaporation gas in the cold heat recovery device (440) is recovered back to the ammonia storage tank (110), so that the temperature of the ammonia storage tank (110) can be maintained low.

[0463]

[0464] When the re-liquefaction unit (800) described below is in operation, the LNG evaporation gas supplied from the LNG storage tank (600) to the gas fuel compressor (720) may be supplied to the gas fuel compressor (720) after the cold heat is recovered in the re-liquefaction unit (800).

[0465] The cold heat of the LNG boil-off gas recovered in the re-liquefaction unit (800) can be used as cold heat to condense the LNG boil-off gas to be re-liquefied.

[0466] When the re-liquefaction unit (800) is not in operation, the LNG boil-off gas supplied from the LNG storage tank (600) to the gas fuel compressor (720) can bypass the re-liquefaction unit (800) and pass through the cold heat recovery device (440), or bypass the cold heat recovery device (440) and be supplied to the gas fuel compressor (720).

[0467]

[0468] A gas fuel supply unit (700) according to one embodiment of the present invention may further include a fuel pressurization pump (730) that receives LNG stored in an LNG storage tank (600) and compresses it to satisfy a pressure condition required by a gas turbine (GT), and a fuel vaporizer (740) that vaporizes the compressed LNG to generate natural gas that satisfies a pressure condition required by the gas turbine (GT).

[0469] When the amount of LNG vaporization gas generated in the LNG storage tank (600) is less than the flow rate of natural gas required by the gas turbine (GT) or generator engine (GE) and boiler (BR), forced vaporization gas can be generated using a fuel pressurization pump (730) and a fuel vaporizer (740) and supplied as gas fuel.

[0470] The LNG storage tank (600) may be equipped with an LNG supply pump (710) to discharge liquid LNG stored in the LNG storage tank (600) to the outside of the LNG storage tank (600).

[0471] In the case where two or more LNG storage tanks (600) are installed as cargo tanks, the LNG supply pump (710) may be installed only in some of the two or more LNG storage tanks (600).

[0472] For example, in the case where a ship according to the present embodiment is equipped with four LNG storage tanks (600) as cargo tanks, the LNG supply pump (710) may be equipped only in the third LNG storage tank and the fourth LNG storage tank installed on the stern side.

[0473]

[0474] The fuel pressure pump (730) can pressurize the LNG transported by the LNG supply pump (710) to 30 to 40 barg, or about 36 barg.

[0475] The fuel vaporizer (740) can vaporize LNG pressurized by the fuel pressure pump (730) at 20 to 30°C, or about 25°C.

[0476]

[0477] The forced vaporization gas generated in the fuel vaporizer (740) can be supplied as fuel to a gas turbine (GT), and can also be supplied as fuel to a generator engine (GE) and boiler (BR) through a pressure reducing device.

[0478]

[0479] When the amount of LNG boil-off gas generated in the LNG storage tank (600) is equal to or greater than the amount of gas fuel required by the gas turbine (GT), generator engine (GE), and boiler (BR), the LNG boil-off gas can be compressed in the gas fuel compressor (720) after cold heat is recovered in at least one of the cold heat recovery device (440) and the re-liquefaction device (830) through the gas fuel supply line (GL) and supplied as fuel to at least one of the gas turbine (GT), generator engine (GE), and boiler (BR).

[0480] When the amount of LNG boil-off gas generated in the LNG storage tank (600) is less than the amount of gas fuel required by the gas turbine (GT), the generator engine (GE), and the boiler (BR), the LNG pressurized using the LNG supply pump (710) is supplied to the fuel pressurization pump (730) through the forced vaporization line (LL), and the LNG compressed in the fuel pressurization pump (730) is vaporized in the fuel vaporizer (740), and the generated forced vaporization gas can be supplied as fuel to one or more of the gas turbine (GT), the generator engine (GE), and the boiler (BR).

[0481]

[0482]

[0483] <Method of providing heat source with fuel carburetor (740)>

[0484] The heat source for vaporizing LNG in the fuel vaporizer (740) according to one embodiment of the present invention can be supplied from a heat source supply unit (300) or a waste heat recovery unit (200).

[0485] In the embodiments described below, the heat source demander that uses the residual heat of carbon dioxide recovered in the heat recovery cooler (270) of the waste heat recovery unit (200) described above may be a fuel vaporizer (740).

[0486]

[0487] Hereinafter, with reference to FIGS. 18 and 19, an embodiment of supplying a heat source to a fuel vaporizer (740) of a gas fuel supply unit (700) will be described.

[0488] In order to control the efficiency of ship operation and the internal pressure of the LNG storage tank (600), LNG BOG naturally vaporized inside the LNG storage tank (600) is given priority to be supplied as fuel for a gas turbine (GT) or generator engine (GE), but in cases where gas fuel is insufficient, LNG stored in the LNG storage tank (600) may be vaporized and used as fuel.

[0489] A fuel vaporizer (740) can be used to vaporize LNG, and a heat source for vaporizing LNG must be supplied to the fuel vaporizer (740).

[0490]

[0491] First, as an example, referring to FIG. 18, the gas fuel supply unit (700) according to the present embodiment may further include a vaporization heat source line (HL4) branched from the supersonic line (SL) between the recuperator (240) and the precooler (250) of the waste heat recovery unit (200) and connected to the fuel vaporizer (740).

[0492] Expanded carbon dioxide supplied from a supercritical turbine (230) or recuperator (240) to a precooler (250) or a supercritical compressor (260) through a supercritical line (SL) can be supplied to a fuel vaporizer (740) along a vaporization heat source line (HL4) downstream of the supercritical turbine (230) or recuperator (240).

[0493] At this time, in the fuel vaporizer (740), the carbon dioxide transferred through the vaporization heat source line (HL4) and the LNG transferred through the forced vaporization line (LL) exchange heat, so that the carbon dioxide is cooled and the LNG is vaporized and heated by the residual heat of the carbon dioxide.

[0494] Carbon dioxide cooled after heat exchange in the fuel vaporizer (740) can be circulated to the supercritical compressor (260) or precooler (250) through a vaporization heat source line (HL4) connected from the fuel vaporizer (740) to a supercritical line (SL) upstream of the supercritical compressor (260) or precooler (250).

[0495] That is, according to the embodiment illustrated in FIG. 18, the heat recovery cooler (270) described above may be a fuel vaporizer (740).

[0496] Meanwhile, the vaporization heat source line (HL4) may further include at least one of a vaporization heat source valve (760) provided upstream of a fuel vaporizer (740) and a heat source branch valve (290) provided in a supercritical line (SL) downstream of a point where the vaporization heat source line (HL4) branches off downstream of a recuperator (240) and upstream of a point where the vaporization heat source line (HL4) joins the supercritical line (SL).

[0497] The vaporization heat source valve (760) can supply carbon dioxide to the fuel vaporizer (740) from downstream of the recuperator (240) by opening and closing control, and can adjust the flow rate of carbon dioxide supplied to the fuel vaporizer (740) by opening amount control.

[0498] The heat source branch valve (290) can control the opening and closing so that carbon dioxide is not supplied to the fuel vaporizer (740) downstream of the recuperator (240) but to the precooler (250) or the supercritical compressor (260), and can control the flow rate of carbon dioxide supplied to the precooler (250) or the supercritical compressor (260) by bypassing the fuel vaporizer (740) by controlling the opening amount.

[0499]

[0500] When the gas turbine (GT) is initially started and when the load is below a certain level, for example, below 60%, it can operate in a mode that uses natural gas as fuel until the operation of the gas turbine (GT) stabilizes. At this time, the natural gas supplied as fuel to the gas turbine (GT) can be used entirely as LNG boil-off gas, so the fuel vaporizer (740) may not be operated.

[0501] When the fuel vaporizer (740) is not in operation, the vaporization heat source valve (760) is controlled to be closed and the heat source branch valve (290) is controlled to be open, so that carbon dioxide with residual heat recovered in the recuperator (240) bypasses the fuel vaporizer (740) and is cooled in the precooler (250).

[0502] In preparation for a situation where the fuel vaporizer (740) is not used, the precooler (250) may be selected with a capacity sufficient to cool all the heat of carbon dioxide in a state where no additional residual heat is recovered after the waste heat is recovered from the recuperator (240).

[0503] Meanwhile, when the load of the gas turbine (GT) is at its maximum in a high-speed section or other mode and only natural gas is used as fuel, LNG vaporization gas alone is not enough, so forced vaporization gas must also be supplied as fuel. In this case, the fuel vaporizer (740) must be operated.

[0504] When the mode is changed to operate the fuel vaporizer (740), the vaporization heat source valve (760) is controlled to open gradually so that carbon dioxide is supplied to the fuel vaporizer (740), and the heat source branch valve (290) is controlled to close gradually.

[0505] In addition, when the mode is changed to not operate the fuel vaporizer (740), the vaporization heat source valve (760) is controlled to close gradually so that the carbon dioxide bypasses the fuel vaporizer (740) and is cooled in the precooler (250), and the heat source branch valve (290) is controlled to open gradually.

[0506] The vaporization heat source valve (760) and the heat source branch valve (290) can be organically controlled to adjust the flow rate of carbon dioxide supplied to the fuel vaporizer (740) in order to supply the amount of heat required by the fuel vaporizer (740).

[0507] According to this embodiment, since the waste heat of the waste heat recovery unit (200) is used to vaporize and heat LNG, an additional heat source such as steam is not required, and thus the fuel required for steam generation can be reduced, thereby reducing operating costs and reducing environmental impact.

[0508]

[0509] As another embodiment, referring to FIG. 19, the gas fuel supply unit (700) according to the present embodiment may further include a heat medium vaporization line (HL5) branched from the heat medium circulation line (HL) and connected to a fuel vaporizer (740).

[0510] According to the present embodiment, a cycle can be formed in which the heat medium is heated in at least one of a heat recovery cooler (270) and a heat medium heater (330), then supplied to a fuel vaporizer (740) through a heat medium vaporization line (HL5), cooled by heat exchange with LNG in the fuel vaporizer (740), and rejoined to the heat medium circulation line (HL) upstream of the heat medium tank (310) through the heat medium vaporization line (HL5).

[0511] When a situation arises where a heat source needs to be supplied to the fuel vaporizer (740) while the waste heat recovery unit (200) is in operation, the heat medium discharged from the heat medium tank (310) by the heat medium circulation pump (320) is supplied to the heat recovery cooler (270) through the heat medium circulation line (HL), and after being heated by the waste heat of carbon dioxide in the heat recovery cooler (270), can be supplied to the fuel vaporizer (740) through the heat medium vaporization line (HL5). The heat medium cooled while vaporizing LNG in the fuel vaporizer (740) is recycled back to the heat medium tank (310).

[0512] When a situation arises where a heat source needs to be supplied to the fuel vaporizer (740) while the waste heat recovery unit (200) is not in operation, the heat medium discharged from the heat medium tank (310) by the heat medium circulation pump (320) is supplied to the heat medium heater (330) through the steam heating line (HL1), heated by heat exchange with steam in the heat medium heater (330), and then supplied to the fuel vaporizer (740) through the heat medium vaporization line (HL5). The heat medium cooled while vaporizing LNG in the fuel vaporizer (740) is recycled back to the heat medium tank (310).

[0513]

[0514] In this way, by vaporizing LNG using a heat medium heated by at least one of the waste heat of carbon dioxide and steam, even if the waste heat of carbon dioxide is utilized, it is possible to prevent the problem of mutual contamination because it does not come into direct contact with LNG.

[0515] In addition, since waste heat from a waste heat recovery unit (200) is used as a heat source in addition to steam, which was previously used as a heat source for vaporizing LNG, the amount of steam used can be reduced, thereby reducing the energy and operating costs (OPEX) required for vaporizing LNG.

[0516]

[0517]

[0518] <Reliquefaction Department (800)>

[0519] Referring again to FIG. 17, the ammonia gas turbine fuel supply system according to embodiments of the present invention may further include a re-liquefaction unit (800) for re-liquefying LNG evaporation gas generated by natural vaporization of LNG stored in an LNG storage tank (600) and returning it back to the LNG storage tank (600).

[0520] When the engines of the present embodiment, i.e., the gas turbine (GT), the generator engine (GE), and the boiler (BR), are operated in a mode using natural gas as fuel, LNG boil-off gas, which is natural gas vaporized in the LNG storage tank (600), can be supplied as fuel first.

[0521] When the amount of LNG boil-off gas discharged from the LNG storage tank (600) is greater than the natural gas fuel flow rate required by the gas turbine (GT) or generator engine (GE) and boiler (BR), the LNG boil-off gas is re-liquefied using the re-liquefaction unit (800) and returned to the LNG storage tank (600), thereby preventing the pressure of the LNG storage tank (600) from increasing excessively.

[0522] The re-liquefaction unit (800) can be designed to have a capacity to re-liquefy all of the LNG boil-off gas discharged from the LNG storage tank (600).

[0523] When the re-liquefaction unit (800) is in operation, the LNG evaporation gas discharged from the LNG storage tank (600) can be introduced to the evaporation gas compressor (810) after the evaporation gas has had its evaporation heat recovered in the re-liquefaction device (830) so that the evaporation gas can be re-liquefied by recovering the evaporation heat.

[0524] Meanwhile, if the amount of LNG boil-off gas discharged from the LNG storage tank (600) is equal to or less than the amount of natural gas fuel required by the gas turbine (GT), generator engine (GE), and boiler (BR), the re-liquefaction unit (800) does not operate, so the LNG boil-off gas bypasses the re-liquefaction unit (800) and is supplied to the gas fuel compressor (720) and compressed to meet the pressure conditions required by the engine.

[0525]

[0526] The re-liquefaction unit (800) may include at least one of a vaporization gas compressor (810) that compresses vaporization gas to be re-liquefied, and a re-liquefaction device (830) that condenses vaporization gas compressed in the vaporization gas compressor (810).

[0527] The evaporation gas compressor (810) can be used for the same function as the gas fuel compressor (720), such as regulating the pressure of the LNG storage tank (600), except that it compresses the LNG evaporation gas and supplies it as fuel to one or more of a gas turbine (GT), a generator engine (GE), and a boiler (BR).

[0528]

[0529] The boil-off gas compressor (810) can compress the LNG boil-off gas to a pressure required by the generator engine (GE) and boiler (BR), for example, about 10 to 20 barg, or about 13 barg.

[0530] The temperature of the evaporation gas compressed at about 13 barg in the evaporation gas compressor (810) may be about 45°C.

[0531] Additionally, the boil-off gas compressor (810) can be used to supply LNG boil-off gas to the re-liquefaction device (830) when the gas fuel compressor (720) is inoperative, when the gas turbine (GT) is not operating in a mode using natural gas as fuel, or when there is no natural gas consumption.

[0532]

[0533] In addition, the re-liquefaction device (830) may further include a refrigerant circulation device (820) that circulates refrigerant to condense the compressed evaporation gas.

[0534] The refrigerant circulating through the refrigerant circulation device (820) and re-liquefaction device (830) of the present embodiment may be liquid nitrogen.

[0535]

[0536] *When the gas turbine (GT), generator engine (GE) and boiler (BR) are not operated in a mode using natural gas as fuel, or the remaining LNG boil-off gas exceeding the required amount of gas fuel is supplied to the boil-off gas compressor (810) upstream of the gas fuel compressor (720), compressed, and condensed in the re-liquefaction device (830) by at least one low-temperature energy of the cold heat of the boil-off gas before compression and the cold heat of the refrigerant circulating in the refrigerant circulation device (820). The condensed re-liquefied boil-off gas can be recovered to the LNG storage tank (600) through the re-liquefaction recovery line (TL).

[0537]

[0538]

[0539] *In addition, the re-liquefaction device (830) can recover the cold heat of the ultra-low temperature LNG evaporation gas supplied to the gas fuel compressor (720) or the evaporation gas compressor (810) and use it as cold heat to re-liquefy the compressed evaporation gas.

[0540] That is, the LNG boil-off gas supplied from the LNG storage tank (600) to the gas fuel compressor (720) or boil-off gas compressor (810) can be heated while recovering cold heat in the re-liquefaction device (830) and then introduced into the gas fuel compressor (720) or boil-off gas compressor (810).

[0541] When both a cold heat recovery device (440) and a re-liquefaction device (830) are provided, the LNG boil-off gas supplied from the LNG storage tank (600) to the gas fuel compressor (720) or the boil-off gas compressor (810) can be supplied to the gas fuel compressor (720) or the boil-off gas compressor (810) after first recovering cold heat through heat exchange with the LNG boil-off gas to be re-liquefied in the re-liquefaction device (830) and secondly recovering cold heat through heat exchange with ammonia to be cooled in the cold heat recovery device (440).

[0542]

[0543] In LNG carriers, a gas fuel compressor (720) is applied for the purpose of controlling the pressure of an LNG storage tank and supplying fuel gas. Using the gas fuel compressor (720), LNG boil-off gas can be supplied to a gas turbine (GT), a generator engine (GE), and a re-liquefaction unit (800).

[0544] Considering the situation where the gas fuel compressor (720) cannot be used (failure) according to classification and international regulations, one more spare compressor of the same specifications is applied.

[0545] That is, it is common to configure redundancy so that at least two gas fuel compressors (720) and evaporative gas compressors (810) are each installed, and when one of them is in operation, at least one is in standby mode, and when one of the operating compressors becomes unusable, the compressor in standby mode can be used. However, since the gas fuel compressor (720) accounts for a large portion of the installation cost (CAPEX), it often affects the ship price.

[0546] According to embodiments of the present invention, the gas fuel compressor (720) compresses LNG boil-off gas to a pressure required by a gas turbine (GT), for example, about 30 to 40 bar, and can also compress and supply to 13 bar to supply to a generator engine (GE), a boiler (BR), and a re-liquefaction device (830).

[0547] The evaporative gas compressor (810) has the same capacity as the gas fuel compressor (720), but has an output pressure of 13 bar, which can be supplied to the generator engine (GE), boiler (BR), and reliquefaction device (830).

[0548] Referring to Fig. 20, in order to improve the above-described problem, in the present embodiment, one gas fuel compressor (720) and one evaporation gas compressor (810) are each provided, and the gas fuel compressor (720) and the evaporation gas compressor (810) can be configured to have redundancy with each other.

[0549] The gas fuel compressor (720) operates in a mode of supplying natural gas as fuel for a gas turbine (GT) or a generator engine (GE), and the evaporative gas compressor (810) operates in a mode of supplying natural gas as fuel for a generator engine (GE) or to a re-liquefaction device (830), so that the same redundancy configuration is possible.

[0550] That is, instead of providing an additional spare gas fuel compressor (720) of the same specifications, the LNG boil-off gas can be processed using the boil-off gas compressor (810) in a situation where the gas fuel compressor (720) cannot be used.

[0551] The boil-off gas compressor (810) of the present embodiment is not only for the purpose of re-liquefying LNG boil-off gas, but can also be operated in the event of a failure of the gas fuel compressor (720) to supply LNG BOG as fuel to a gas turbine (GT), a generator engine (GE), or a boiler (BR), and can also be supplied to a re-liquefaction device (830) to re-liquefy LNG boil-off gas and lower the pressure of an LNG storage tank (600).

[0552] When the gas fuel compressor (720) is in a malfunction state, the LNG boil-off gas cannot be supplied as fuel to the gas turbine (GT), and in this case, the LNG boil-off gas is supplied as fuel to the generator engine (GE) or boiler (BR) using the boil-off gas compressor (810).

[0553] When the amount of LNG boil-off gas is greater than the amount of fuel consumed, the LNG boil-off gas compressed in the boil-off gas compressor (810) is sent to the re-liquefaction device (830) to be re-liquefied and processed.

[0554] Meanwhile, even when the gas fuel compressor (720) is available but the gas turbine (GT) is not operated in a mode that uses LNG boil-off gas as fuel, considering energy efficiency, the LNG boil-off gas is compressed using the boil-off gas compressor (810) in the same way as when the gas fuel compressor (720) is disabled and supplied to the generator engine (GE), boiler (BR), or re-liquefaction device (830).

[0555]

[0556]

[0557] Generator Engine (GE) and Boiler (BR)

[0558] In addition, the engine of the ammonia gas turbine fuel supply system according to embodiments of the present invention may further include at least one of a generator engine (GE), which is an internal combustion engine that generates electricity using LNG as fuel, and a boiler (BR) that generates steam using LNG as fuel.

[0559] In cases where the output of the gas turbine (GT) alone cannot meet the power demand from power demand sources such as propulsion motors, a generator engine (GE) may be installed to supplement the power shortage and to prepare for situations where the gas turbine (GT) cannot be operated.

[0560] For example, when a ship is sailing, it mainly uses a gas turbine (GT) to generate the power required for propulsion and the power required for onboard power demand sources. When the ship is operating at low speed or at anchor, the amount of power required for propulsion and power demand sources is not large, so the load is low, and power can be generated using a generator engine (GE) rather than operating a gas turbine (GT).

[0561] Additionally, when a ship is operating at high speed, the gas turbine (GT) alone may not be enough to generate the power required for propulsion, so a gas turbine (GT) and a generator engine (GE) can be used together to generate the power required for propulsion and power demand.

[0562] At this time, a power management system (not shown) may be provided to manage the power generated by the gas turbine (GT) and generator engine (GE) and distribute and supply it to the propulsion unit and power demanders.

[0563]

[0564] The generator engine (GE) according to embodiments of the present invention may be a dual fuel diesel generator engine (DFDG) that can selectively use LNG, i.e. natural gas, and fuel oil, either alone or in combination, as fuel.

[0565] Generator engines (GE) can also be used as a means to process LNG boil-off gas.

[0566] The gas fuel supply line (GL) may be equipped with a gas fuel main supply valve (not shown) for the generator engine to supply or cut off natural gas supplied to the generator engine (GE).

[0567]

[0568] The boiler (BR) of the present embodiment may be a dual-fuel boiler that can selectively use natural gas and fuel oil, either singly or in combination, as fuel.

[0569] In addition, the boiler (BR) may have a function of generating steam to be supplied to a steam demand source, and may be operated in GCU mode to combust and process LNG boil-off gas when the LNG boil-off gas cannot be supplied to a gas turbine (GT) or generator engine (GE) or cannot be re-liquefied in a re-liquefaction unit (800).

[0570] Depending on the boiler (BR) capacity, all of the LNG boil-off gas may be processed in the boiler, or a portion of the LNG boil-off gas may be processed in the boiler (BR) by operating together with the gas turbine (GT) and generator engine (GE).

[0571] When the boiler (BR) is operated in GCU mode, a steam condensation system may be further provided to condense the excess steam generated by using LNG boil-off gas as fuel in the boiler (BR).

[0572] Meanwhile, the gas fuel supply line (GL) may be equipped with a boiler gas fuel main supply valve (not shown) for supplying or cutting off natural gas supplied to the boiler (BR).

[0573]

[0574] In this embodiment, low sulfur marine gas oil (LSMGO) may be used as fuel oil. Although not illustrated in the drawing, when the ammonia gas turbine fuel supply system according to this embodiment is applied to an LNG carrier, the vessel of this embodiment may further include a fuel oil supply system (not illustrated) for supplying fuel oil as fuel for a generator engine (GE) and a boiler (BR). A known fuel oil supply system may be used.

[0575]

[0576] When the gas turbine (GT) is unavailable, the generator engine (GE) can be used to generate electricity. Furthermore, when the ship is at anchor (including loading and unloading), a dual-fuel generator engine (GE) can be used to generate and supply electricity, as a large amount of electricity is not required.

[0577] In this embodiment, an example is given in which two generator engines (GE) are provided.

[0578] Typically, when there is no cargo, one generator engine can be operated to supply power to onboard power needs.

[0579] On the other hand, when a vessel is anchored while carrying cargo, a large amount of LNG vapor is generated, and to control this, the re-liquefaction unit (800) is operated, which increases the required power. To prepare for this, two generator engines (GE) can be designed to handle this amount of power.

[0580] During loading and unloading, electric heaters are generally operated to generate steam required by the steam demand sources on board, but when a large amount of steam is required, a boiler (BR) can be operated to generate steam.

[0581] Since the amount of LNG evaporation gas generated in the LNG storage tank (600) changes depending on the presence or absence of cargo, and accordingly the amount of power required in the re-liquefaction unit (800) changes, the operating load (speed) of the engine generating power in this embodiment, i.e., the gas turbine (GT) and generator engine (GE), may change.

[0582]

[0583] According to one embodiment of the present invention, an economizer (not shown) may be further included to recover waste heat from exhaust gas discharged from a generator engine (GE) to generate steam.

[0584] When the generator engine (GE) is operated in high-speed, low-speed and anchored conditions, steam is generated by the generator economizer connected to the generator engine (GE).

[0585] A steam heating line (not shown) may be provided so that steam generated from the economizer can be used at an onboard steam demand location. Here, the onboard steam demand location may include the heat source supply unit (300) described above.

[0586] Steam can be generated from the waste heat of exhaust gas discharged from a generator engine (GE) using an economizer, and used as a heat source for heating water as a heat medium in an onboard heat medium heater (330), for example.

[0587]

[0588]

[0589]

[0590] <Layout>

[0591] Hereinafter, with reference to FIGS. 21 to 24, the arrangement structure of a ship to which an ammonia gas turbine fuel supply system according to embodiments of the present invention described above is applied will be described.

[0592] According to embodiments of the present invention, a vessel can use all of the LNG boil-off gas generated in an onboard LNG storage tank (cargo hold) as fuel even when using a mixture of ammonia and natural gas, thereby increasing fuel efficiency.

[0593] Additionally, even when using natural gas as fuel, the amount of methane emitted without combustion can be drastically reduced compared to the engine that emits the least methane among existing engines.

[0594] In addition, by using a gas turbine (GT) smaller in size than a conventional diesel engine as the main propulsion engine for propulsion of the ship, the ammonia storage tank (110) and the ammonia fuel supply unit (100) can be arranged without changing the length of the ship.

[0595]

[0596] A ship according to one embodiment of the present invention can be broadly divided into a stern area (A), an engine room area (E), an ammonia storage tank (110), an ammonia fuel preparation room (P), an LNG storage tank (cargo tank) (600), a cargo compressor room (C), a cabin area (Q), and a bow area (F).

[0597] Referring to FIGS. 23 and 24, the ammonia fuel supply unit (100) is placed within the ammonia fuel preparation room (P), and the ammonia fuel preparation room (P) can be installed on the outer deck (D).

[0598] The gas fuel supply unit (700) is arranged in the cargo compressor room (C), and the cargo compressor room (C) can be arranged on the opposite side of the ammonia fuel preparation room (P) on the outer deck (D). For example, if the ammonia fuel preparation room (P) is arranged on the starboard side, the cargo compressor room (C) can be arranged on the port side.

[0599] Gas turbines (GT), generator engines (GE) and boilers (BR) can be installed in the engine room area (E).

[0600] Meanwhile, by using an ammonia gas turbine electric propulsion system, the ammonia storage tank (110) may be placed in the engine room area (E), thereby reducing the area of ​​the engine room area (R). In addition, since the ammonia storage tank (110) is placed in contact with the engine room and at the location where the LNG storage tank (cargo hold) (600) is placed, the cabin area (Q) may be placed on the bow side.

[0601]

[0602] As another embodiment, as shown in FIGS. 25 and 26, the ammonia storage tank (110) may be placed in the bow area (F), and the cabin area (Q) may be configured to be located above the engine room.

[0603]

[0604] Meanwhile, the waste heat recovery unit (200) is provided in a separate room on the upper part of the stern section (A) and is placed therein.

[0605] The waste heat recovery unit (200) includes a waste heat recovery device (220) for recovering exhaust gas waste heat of a gas turbine (GT), and the waste heat recovery device (220) can be arranged to be connected to a chimney (U).

[0606] When the waste heat recovery device (220), the ammonia vaporizer (150), and the fuel vaporizer (740) are circulated using a heat medium, the heat source supply unit (300) can be placed in the ammonia fuel preparation room (P) or the engine room (R). Alternatively, some of the components included in the heat source supply unit (300) can be placed in the ammonia fuel preparation room (P) or the cargo compressor room (C), and the remaining components can be placed in the engine room (R). The heat source supply unit (300) has the advantage of connecting the waste heat recovery unit (200), which is geographically distant, and the ammonia fuel preparation room (P) and the cargo compressor room (C).

[0607]

[0608] Meanwhile, international regulations require that the pressure of an LNG storage tank (600) be controlled for safety reasons. In this embodiment, in order to control the pressure of an LNG storage tank (600), LNG boil-off gas is discharged from the LNG storage tank (600), and the discharged LNG boil-off gas is supplied as fuel to one or more of the engines of this embodiment, i.e., a gas turbine (GT), a generator engine (GE), and a boiler (BR).

[0609] As a conventional method for processing LNG boil-off gas, LNG boil-off gas is used as fuel, and when the fuel demand is exceeded, it is re-liquefied and processed. However, in cases where both fuel supply and re-liquefaction are impossible for some reason, a method of incinerating using a gas combustion unit (GCU) for the purpose of maintaining the pressure of an LNG storage tank (600) has been generally used.

[0610] Gas incinerators have the problem of being large in size, taking up a lot of space, wasting energy when processing evaporated gas by incineration, and also emitting carbon dioxide.

[0611] According to embodiments of the present invention, to solve this problem, a gas incinerator is not installed on the ship.

[0612] A ship according to embodiments of the present invention can reduce GCU installation costs by using a gas turbine (GT) as a substitute for a GCU, utilize the GCU installation space in various ways, and reduce the weight of the ship.

[0613] In the case of a gas turbine (GT), it does not produce power and operates in idling mode from 0% load until it reaches the minimum load at which power can be generated. Since natural gas is used as fuel in the idling mode, the gas turbine (GT) can replace the role of a gas incinerator when operating in the idling mode, and depending on the capacity of the gas turbine (GT), all LNG boil-off gas can be incinerated.

[0614] When using a small-capacity gas turbine (GT), the role of the existing gas incinerator can be replaced by the operation combination of the re-liquefaction unit (800), gas turbine (GT), generator engine (GE), and boiler (BR), so that all LNG boil-off gas can be processed.

[0615] The gas turbine (GT), generator engine (GE), and boiler (BR) of this embodiment can use LNG boil-off gas as fuel. Furthermore, the gas turbine (GT) and generator engine (GE) can operate in no-load mode to consume LNG boil-off gas even when there is no power generation load, and the boiler can also operate in GCU mode to combust natural gas. The excess steam generated during boiler GCU mode operation can be condensed and disposed of.

[0616] For example, the estimated LNG evaporation gas amount when the outside temperature is 35℃ is 1,750 kg / h (100%).

[0617] According to embodiments of the present invention, a gas turbine (GT) is continuously operated at a minimum load (20%) in a no-load operation mode to process about 1,050 kg / h (60%) of boil-off gas, and about 200 kg / h (10%) of boil-off gas is combusted as the basic gas consumption required for generating basic power of a generator engine (GE), and about 500 kg / h (30%) of boil-off gas is combusted as the gas consumption when operating a boiler (BR) in GCU mode, so that the entire amount of LNG boil-off gas can be incinerated and processed.

[0618] The gas turbine capacity can be designed to process all LNG boil-off gas generated from the LNG storage tank by incineration through a combination of operation modes, such as no-load operation and GCU mode, of each piece of equipment, when necessary, and the boil-off gas processing ratio of each piece of equipment can be arbitrarily adjusted according to the characteristics of the installed equipment and the ship's operating conditions.

[0619]

[0620]

[0621] <als>

[0622] The systems of this embodiment further include an Air Lubrication System (ALS) installed on the vessel to inject air onto the outer bottom surface of the vessel's hull to reduce frictional resistance during vessel movement. The ALS injects air onto the outer bottom surface of the vessel, thereby continuously forming an air layer between the vessel and the seawater, thereby reducing frictional resistance between the seawater and the vessel as the vessel moves, thereby improving fuel efficiency.

[0623] The air lubrication system (ALS) is composed of an air compressor for injecting air into the bottom of a ship, a pipe for moving the air, an air injection unit, an air layer formed on the surface of the bottom of the hull, a control unit, etc. In the present exemplary systems, by supplying combustion air (bleeding compressed air) or a portion of the ammonia exhaust gas discharged from the gas turbine to the air lubrication system and utilizing it as lubrication air, the installation cost of the device can be reduced by not installing an air compressor, and the power consumption required to operate the air compressor can also be reduced, thereby reducing the operating cost. The combustion air or exhaust gas of a gas turbine is approximately 30 to 34 bar, and the air injection pressure in the air lubrication system is lower than that, so it can be injected by reducing the pressure accordingly. Accordingly, there is an effect of reducing the air flow rate required for the operation of the air lubrication system.

[0624] By configuring the air lubrication system in this way, the frictional resistance during ship operation can be reduced, thereby improving fuel efficiency, and the costs required for configuring and operating the air lubrication system can be reduced. In addition, by driving it with a generator engine that uses ammonia as fuel, the effect of reducing greenhouse gas emissions during ship operation can be further increased.

[0625]

[0626]

[0627] <Gas turbine operation according to load from start-up>

[0628] The gas turbine of this embodiment operates without load and does not produce power from the time of starting until a certain load is reached, and even if it is a gas turbine that can be supplied with ammonia and natural gas as fuel, the fuel supply may be limited depending on a specific load.

[0629]

[0630] In these examples, the operating sections of the gas turbine are first classified into the following three based on the load.

[0631] 1. Idling section - The period from when the gas turbine load is 0% until it reaches the minimum load (BP) at which power generation is possible (0 < gas turbine load (%) ≤ BP)

[0632] 2. First power generation section - from minimum load to constant load (TP) (BP < gas turbine load (%) ≤ TP)

[0633] 3. Second generation section - When the constant load is exceeded (TP < gas turbine load (%))

[0634] As previously described, conventional main propulsion engines require pilot oil for ignition. However, the gas turbines employed in the vessels of this embodiment operate without pilot oil. However, from startup until a certain load is reached, the gas turbines do not use ammonia as fuel; instead, they are supplied only with natural gas as fuel and do not generate electricity. The no-load operation period refers to the period in which the turbines are supplied with natural gas as fuel but do not produce electricity. The minimum load for power generation may vary depending on the gas turbine and may be, for example, 50%. During the no-load operation period, power supplied to onboard power demands, including propulsion power, may be generated by the generator engine.

[0635] The first power generation section is where the gas turbine generates electricity beyond the minimum power load (BP) for power generation, but still relies solely on natural gas as fuel. The gas turbine generates the power needed onboard, using only natural gas as fuel, until it reaches a certain load, the minimum load required for fuel switching. The minimum load for fuel switching can also vary depending on the gas turbine, for example, as high as 60%.

[0636] The second power generation section is where the gas turbine load exceeds the minimum fuel conversion load, allowing the gas turbine fuel to be converted to ammonia and used for combustion or for co-firing ammonia and natural gas. In this section, ammonia and natural gas are co-fired at 0-100% as needed, or ammonia or natural gas is co-fired as needed to generate the power needed onboard.

[0637]

[0638] The operating modes of gas turbines are classified into the following two based on the selection of fuel supplied to the gas turbine.

[0639] 1. Natural gas operation mode - supplies only natural gas as fuel to the gas turbine.

[0640] 2. Fuel selection operation mode - fuel can be selectively supplied to the gas turbine from ammonia and natural gas.

[0641] When this is examined together with the load-based operating section of the gas turbine, the gas turbine is operated without pilot oil when started, and operates in natural gas operating mode in the no-load operating section and the first power generation section, and switches to fuel selection operating mode in the second power generation section.

[0642] Gas turbines are more efficient at higher loads. Therefore, when the ship's total power demand, including propulsion, can be met solely by operating the gas turbine, the gas turbine load can be increased to operate solely. Once the gas turbine reaches its minimum load, the load on the generator engine in the first and second power generation sections can be reduced and the gas turbine load gradually increased, allowing the gas turbine to produce all the power needed for power demand, including propulsion.

[0643] For example, from the time of starting to 60% of the operating load, the engine is operated in natural gas operation mode using only natural gas as fuel, and when the gas turbine operating load exceeds 60%, it is operated in fuel selection operation mode, so that ammonia and natural gas can be used as fuels, either singly or in combination, as needed.

[0644]

[0645] As previously mentioned, during no-load operation, the gas turbine is not in operation. Therefore, the generator engine generates the power required to meet the ship's total power demand, including propulsion power, to be supplied to onboard power sources. If the gas turbine alone can meet the total power demand, power can be generated solely by the gas turbine. Thus, based on the operation of the gas turbine and generator engine, gas turbine operating modes are categorized into the following three categories.

[0646] 1. Generator-only operation mode - A mode in which the generator engine alone produces the power required to meet the total power demand.

[0647] 2. Turbine-only operation mode - A mode in which the gas turbine alone produces the power required to meet total power demand.

[0648] 3. Simultaneous operation mode - A mode in which the generator engine and gas turbine are operated simultaneously to produce the power required for the total power demand.

[0649]

[0650] Gas turbines are more efficient at higher loads. Therefore, when the ship's total power demand can be met solely by the gas turbine, the ship can operate in turbine-only mode while increasing the gas turbine load to generate power. Furthermore, when total power demand is low, such as when the ship is at anchor, or during no-load operation periods, the ship can operate in generator-only mode.

[0651] At this time, in situations where the generator engine or gas turbine is operated alone, such as in generator-only operation mode or turbine-only operation mode, the operating load of each equipment is partially limited to prepare for a sudden increase in load, and it is operated at a limited maximum load value. For example, in turbine-only operation mode, the individual maximum load of the gas turbine can be limited to 95%, and in generator-only operation mode, the maximum load of the generator engine can be limited to 90% to prepare for a sudden increase in load. In simultaneous operation mode, the generator engine and gas turbine are operated together, so the gas turbine can operate without restriction up to 100% of the maximum load, and the maximum load of the generator engine can be partially limited to prepare for a sudden increase in the overall power load. For example, in simultaneous operation mode, the gas turbine can operate up to 100% of the maximum load, and the simultaneous maximum load of the generator engine can be limited to 90%.

[0652] If the total power demand on board can be met by gas turbine operation alone within these limited maximum load values, the turbine-only operation mode can be selected to increase gas turbine efficiency.

[0653] The onboard power management system can select an operating mode and control the load of the gas turbine and generator engines based on the total onboard power demand, which is the sum of propulsion power and onboard power requirements.

[0654]

[0655] <Gas turbine fuel operation mode>

[0656] The fuel operation mode of a gas turbine that can use ammonia and natural gas as fuel is largely composed of the following three modes, and the ship can be operated by selecting one of the modes as needed during operation.

[0657] 1. Ammonia maximum mode - fuel operation mode that supplies ammonia as fuel to the gas turbine first.

[0658] 2. BOG maximum mode - A fuel operation mode that supplies LNG boil-off gas generated from LNG in an LNG storage tank as fuel for the gas turbine and supplies ammonia to compensate for fuel shortage.

[0659]

[0660] *3. Natural gas maximum mode - A fuel operation mode that supplies LNG BOG as fuel to the gas turbine first and supplies LNG in the LNG storage tank by forcibly vaporizing it to compensate for the fuel shortage.

[0661]

[0662] When selecting the ammonia maximum mode, the gas turbine operates using natural gas during the no-load operation period from startup to the minimum load that allows fuel switching of the gas turbine and the first power generation period. From the second power generation period, which exceeds the minimum load for fuel switching (e.g., >60%), the fuel is switched to ammonia, and the load can be maintained by burning ammonia. This mode can minimize carbon dioxide emissions and environmental impact associated with ship operation.

[0663] BOG maximum mode, which operates using natural gas from startup through the no-load operation and the first power generation section, prioritizes LNG boil-off gas (BOG) in the second power generation section, supplementing ammonia to account for fuel shortages and maintaining load through co-firing of natural gas and ammonia. By discharging and processing the boil-off gas from the LNG storage tank, the pressure in the LNG storage tank can be controlled, while co-firing ammonia and natural gas can reduce environmental impact. By prioritizing the use of naturally vaporized natural gas as fuel, the power consumption required for re-liquefaction of the boil-off gas is reduced, enabling economical vessel operation.

[0664] Natural Gas Maximum Mode operates using natural gas from startup, during no-load operation and during the first power generation section, and in the second power generation section, preferentially using naturally vaporized LNG boil-off gas. If boil-off gas alone is insufficient, LNG in the LNG storage tank is forcibly vaporized and supplied to the gas turbine to make up for the fuel shortage, thereby operating solely on natural gas. The discharge of boil-off gas allows the internal pressure of the LNG storage tank to be controlled, and by reducing the power consumption required for re-liquefaction, the vessel can operate economically by using naturally vaporized and forced vaporized natural gas as fuel, which has a high energy density.

[0665]

[0666] Fuel Conversion for Gas Turbines

[0667] As mentioned above, even if a gas turbine uses natural gas and ammonia as fuel, ammonia cannot be used as fuel during initial operation. That is, from startup to initial operation (no-load operation section and first power generation section), only natural gas is used as fuel, and when the gas turbine's operating load reaches a certain range (second power generation section), ammonia can be used as fuel from then on. Depending on the fuel operation mode selection, the gas turbine can be operated by switching the fuel to operate exclusively on ammonia, or, if necessary, by co-firing natural gas with ammonia at 0-100%.

[0668] For example, the supply specifications of ammonia required by a gas turbine are a pressure of 30 to 40 barg and a temperature of about 100°C, and the supply specifications of natural gas can be the same as ammonia, at a pressure of 30 to 40 barg and a temperature of about 40°C.

[0669] In the gas turbine, two lines, a gas fuel supply line (GL) and an ammonia supply line (FL), are provided separately for supplying natural gas and ammonia fuel, and a main supply valve for fuel supply is provided for each supply line, and a gas valve unit is also provided for each supply line inside the enclosure.

[0670] From the start of the gas turbine operation until the minimum load for fuel conversion (no-load operation section and first power generation section), natural gas is supplied to the gas turbine through the gas fuel supply line (GL) for operation.

[0671] During the no-load operation and primary power generation sections of these gas turbines, the gas fuel supply unit (700) operates continuously to supply fuel. The fuel requirement for the gas turbine varies depending on the total onboard power demand, which includes propulsion power and onboard power requirements. Therefore, the amount of natural gas supplied to the gas turbine can be adjusted accordingly.

[0672] In the second generation section where fuel switching is possible, when the crew selects a mode that can use ammonia as fuel (BOG max mode or ammonia max mode), the ammonia supply line is purged to prepare for ammonia fuel supply.

[0673] In addition, for ammonia fuel supply, an ammonia supply pump (120) in an ammonia storage tank (110) is operated to transfer ammonia in the tank to a buffer tank (130). The ammonia supply pump is operated according to the ammonia liquid level in the buffer tank, and if the liquid level does not reach a certain level, the ammonia in the ammonia storage tank is transferred to the buffer tank, and if the liquid level is above a certain level, the operation of the ammonia supply pump is automatically stopped.

[0674] When the liquid level in the buffer tank exceeds a certain level, the ammonia pressurization pump (140) of the ammonia fuel supply unit is operated to pump ammonia and transfer it to the ammonia vaporizer (150). The temperature is measured at the rear end of the ammonia vaporizer, and if it does not reach the supply temperature required by the gas turbine, the ammonia fuel is supplied by circulating it back to the buffer tank.

[0675] In this way, when preparation for supplying ammonia fuel from the ammonia fuel supply unit is completed through purging, the main supply valve (160) of the ammonia fuel supply unit (100) is opened, and the flow control valve (FVa) inside the enclosure is opened so that the required amount of ammonia gas is supplied to the gas turbine according to the selected operation mode and gas turbine load.

[0676] The ammonia pressurized pump (140) is of a speed-adjustable type, so that it can supply ammonia in the amount required by the gas turbine. If the gas turbine requires less than the minimum flow rate of the pump, the surplus flow rate of ammonia pumped from the ammonia pressurized pump is circulated to the buffer tank (130) at the rear end of the ammonia pressurized pump.

[0677] Ammonia is transferred to a buffer tank in a liquid state, pumped from an ammonia pressurized pump, vaporized through an ammonia vaporizer (150), and supplied to a gas turbine in a gaseous state.

[0678] In ammonia maximum mode, the entire fuel supplied to the gas turbine is ultimately converted to ammonia. When the gas turbine fuel conversion to 100% ammonia gas is completed, the gas fuel supply unit (700) stops operating and the gas fuel main supply valve (750) closes. The gas fuel supply line (GL) from the rear end of the gas fuel main supply valve to the gas turbine is purged with compressed air or an inert gas (N2) of the gas turbine, and the purged gas can be burned in the combustion chamber of the gas turbine and discharged as exhaust gas.

[0679] When a gas turbine operating in ammonia maximum mode is stopped or changed to a fuel operation mode using natural gas, the main gas fuel supply valve opens again, the gas fuel supply unit operates, and natural gas is supplied according to the gas turbine load, and the appropriate amount of gas is mixed and operated.

[0680] In the case of ammonia, regulations prohibit the emission of ammonia gas above a certain concentration. Therefore, when a gas turbine running on ammonia is shut down, it can switch to natural gas mode and operate for a certain period of time, purging the ammonia supply line. The purged gas can then be combusted in the gas turbine and discharged overboard as exhaust gas.

[0681] When switching to a gas turbine fuel source while operating on natural gas, the gas fuel supply line can be purged. The purged gas can be combusted in the gas turbine's combustion chamber and discharged overboard as exhaust gas. When the vessel is shut down, the purged gas is discharged overboard through the exhaust gas pipe.

[0682]

[0683] <Examples of driving methods according to ship operation>

[0684] Let's look at some examples of driving methods according to specific ship operation situations, such as when the ship is at anchor or underway.

[0685] 1. When the vessel is at anchor (including loading and unloading)

[0686] When a ship is at anchor, its onboard power needs are low, so generator engines are used to generate and supply power. Ships are equipped with multiple generator engines. For example, if two generator engines are installed, one generator can be operated to meet onboard power needs when no cargo is present.

[0687] When a liquefied natural gas carrier (LNG) is at anchor and carrying cargo, a large amount of LNG boil-off gas is generated. Since this amount is insufficient to fuel the gas turbine, the onboard power requirement increases as the re-liquefaction unit operates to re-liquefy the boil-off gas. Therefore, multiple generator engines are designed with the capacity to handle this increased power demand.

[0688] During loading and unloading, electric heaters are used to supply the necessary steam onboard. If large quantities are needed, boilers can be used to generate steam. Natural gas can be used as fuel for these boilers.

[0689] Generator engines and dual-fuel boilers can use natural gas and fuel oil.

[0690]

[0691] 2. When the ship is in operation

[0692] When the vessel is in operation, it can be operated by selecting a fuel operation mode among ammonia maximum mode, BOG maximum mode, and natural gas maximum mode.

[0693] 1) When operating in ammonia maximum mode

[0694] - Generator engine operation section (generator-only operation mode): When the vessel is operating at low speeds, such as up to the minimum load speed at which power generation by the gas turbine is possible (no-load operation section), the generator engine is used to generate power for propulsion and onboard use. The generator engine generates power using BOG as fuel, and can be operated using low-sulfur marine gas oil when natural gas is unavailable or necessary.

[0695] - Gas turbine operation section (turbine-only operation mode): As ship speed gradually increases during the generator engine operation section, the power demand for propulsion increases. When the increase in ship speed necessitates power generation above the minimum load of the gas turbine (generating section 1 and generating section 2), the onboard power management system gradually reduces the load on the generator engine, allowing operation using only the gas turbine.

[0696] In the first power generation section, natural gas is used as fuel to drive the gas turbine, and in the second power generation section, which exceeds the minimum load for fuel conversion, natural gas and ammonia are supplied together, but the ammonia mixing ratio is gradually increased to switch the gas turbine fuel from natural gas to ammonia, so that ultimately the gas turbine can be driven using only ammonia gas.

[0697] Gas turbines are more efficient at higher loads. Therefore, when the ship's total power demand, including propulsion, can be met solely by gas turbine operation, the gas turbine load can be increased to operate solely on the ship. When operating solely with gas turbines, the gas turbines operate at a limited maximum load to accommodate sudden load fluctuations. For example, the maximum load may be limited to around 95%.

[0698] When the ship is a liquefied natural gas carrier, if the gas turbine is operated in ammonia maximum mode instead of turbine-only operation mode, only ammonia is ultimately used as gas turbine fuel and the generator engine is not operated, so all of the boil-off gas generated in the LNG storage tank can be re-liquefied and processed.

[0699] - Gas turbine and generator operation sections (simultaneous operation mode): In sections where power is required beyond the gas turbine's limited maximum load, for example, above 95% of the gas turbine load, the generator engine operates together with the gas turbine. In ammonia maximum mode, the gas turbine is supplied with ammonia as fuel, and the generator engine, which does not use ammonia as fuel, can be supplied with naturally vaporized or forced natural gas as fuel.

[0700] In simultaneous operation mode with the generator engine, the gas turbine can operate up to 100% load, and the maximum load of the generator engine is limited (e.g. 90%) to prepare for load fluctuations.

[0701]

[0702] 2) When operating in BOG maximum mode

[0703] - Generator engine operation section (generator-only operation mode): Operates identically to ammonia maximum operation. During the gas turbine's no-load operation section, the generator engine uses BOG as fuel to generate propulsion and onboard power.

[0704] - Gas turbine operating section (turbine-only operating mode): When the ship speed is gradually increased in the low-speed generator engine operating section, the power demand required for propulsion increases, and when the power required exceeds the minimum load for power generation of the gas turbine, the power management system gradually reduces the load of the generator engine and increases the load of the gas turbine. Even if it exceeds the minimum load for fuel conversion of the gas turbine, BOG is supplied as a priority as fuel, and only when the fuel demand is not met by BOG alone, ammonia is supplied as supplementary fuel to account for the fuel shortage, so that the load can be maintained by co-firing natural gas and ammonia.

[0705] As mentioned above, when operating using only a gas turbine, the maximum load of the gas turbine is partially limited to prepare for load fluctuations.

[0706] - Gas turbine and generator engine operation section (simultaneous operation mode): In sections where power exceeding the limited maximum load value of the gas turbine is required, such as when a ship is operating at high speed, the generator engine is operated together with the gas turbine. BOG is supplied as fuel to the generator engine. When operating in BOG maximum mode, the generator engine does not use ammonia as fuel, so BOG is supplied to the generator engine first, and the remaining BOG is supplied to the gas turbine, and ammonia is supplied to compensate for the fuel shortage of the gas turbine, allowing the gas turbine to be operated through co-firing.

[0707] As mentioned above, since it is a simultaneous operation mode, the gas turbine can be operated up to 100% load, and the generator engine can be operated with the maximum load limited to prepare for load fluctuations.

[0708]

[0709] 3) When operating in natural gas maximum mode

[0710] - Generator engine operation section (generator only operation mode): Operates in the same manner as the ammonia maximum mode.

[0711] - Gas turbine operation section (turbine-only operation mode): When the ship speed is gradually increased from the low-speed generator engine operation section to medium-speed operation, the power required for the gas turbine power generation exceeds the minimum load (e.g., 50%), and the power management system can reduce the generator engine load and operate using only the gas turbine. In natural gas maximum mode, BOG is supplied as gas turbine fuel first, and LNG in the LNG storage tank is forcibly vaporized to supplement the fuel supply to compensate for the fuel shortage. In standalone operation mode, the gas turbine is operated at a limited maximum load value to prepare for load fluctuations.

[0712] - Gas turbine and generator engine operation sections (simultaneous operation mode): When power exceeding the gas turbine's limited maximum load is required, such as when a ship is operating at high speed, the generator engine operates together with the gas turbine. In natural gas maximum mode, both the gas turbine and generator engine are supplied with natural gas for operation.

[0713] Since it is a simultaneous operation mode, the gas turbine operates up to 100% load, and the generator engine operates with the maximum load partially limited to prepare for load fluctuations. BOG is supplied as fuel to the gas turbine and generator engine, and the insufficient fuel is supplied by forcibly vaporizing liquefied natural gas in the LNG storage tank.

[0714]

[0715] The generator-only operation mode, turbine-only operation mode, and simultaneous operation mode described above can be referred to as low-speed section, medium-speed section, and high-speed section, respectively, based on line speed.

[0716] That is, in the low-speed section, when the ship is anchored or at a speed below the minimum load (e.g., 50%) at which power can be generated by the gas turbine, the total power demand on board, including propulsion, is met by priority operation of the generator engine. The generator engine is a dual-fuel generator supplied with natural gas or low-sulfur marine gas oil (LSMGO), so it can use naturally vaporized natural gas (BOG) or forced vaporized natural gas as fuel, or LSMGO as fuel. As the ship speed gradually increases, the power required for propulsion increases, and when the power required exceeds the minimum load for power generation of the gas turbine (50%), the gas turbine is operated using natural gas from that speed up to the minimum load for fuel conversion.

[0717] The medium-speed section is where the ship's total power demand can be met by the gas turbine. In the first power generation section, the gas turbine operates using only natural gas as fuel. In the second power generation section, the ship's speed exceeds the speed at which ammonia can be used as fuel for the gas turbine. Therefore, the ship operates in turbine-only mode, and the fuel operation mode can be selected from ammonia maximum mode, boil-of-gas maximum mode, and natural gas maximum mode as needed. Depending on the fuel operation mode selected, the ammonia mixing ratio can be gradually increased to operate using only 100% ammonia gas, boil-of-gas can be supplied first and ammonia can be supplied to make up for the fuel shortage through mixing, or boil-of-gas can be supplied first and then forced-vaporized natural gas can be supplied. In turbine-only mode, the gas turbine operates at a limited maximum load to prepare for sudden load fluctuations.

[0718] In high-speed sections, it is difficult to meet the total on-board power demand, including propulsion, solely with the gas turbine. Therefore, the gas turbine and generator engine are operated together (simultaneous operation mode). By operating the generator engine and gas turbine together, the gas turbine can operate up to 100% load, and the maximum load of the generator engine can be limited to prepare for load fluctuations. Since the generator engine does not use ammonia as fuel, it is supplied with naturally or forcedly vaporized natural gas or LSMGO. Depending on the fuel operation mode selected, the gas turbine can either use 100% ammonia, receive the remaining BOG after supplying it to the generator engine first, and then supplement the fuel shortage with ammonia for co-firing, or receive BOG first and then receive forcedly vaporized natural gas.

[0719] The amount of natural gas naturally vaporized in the LNG storage tank varies depending on the presence or absence of cargo in the LNG storage tank and the amount of cargo loaded, and accordingly, the amount of power supply required for re-liquefaction varies, so the ship speed corresponding to the low, medium, and high speed sections may change.

[0720]

[0721]

[0722] In describing the embodiments of the present invention described above, except in cases where it is specifically stated that it is necessarily included or not necessarily required, whether or not a specific description of each embodiment is given and whether or not a specific component or description is shown in each drawing does not mean that the component or description is necessarily included or excluded in applying each embodiment of the present invention, and the components and operating methods described above can be appropriately synthesized and modified to be applied in various ways.

[0723] As described above, embodiments of the present invention have been described. It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms, in addition to the embodiments described above, without departing from the spirit or scope thereof. Therefore, the above-described embodiments should be considered illustrative rather than restrictive, and accordingly, the present invention is not limited to the above description, but may be modified within the scope of the appended claims and their equivalents.

[0724]

[0725] <Explanation of symbols>

[0726] 100: Ammonia fuel supply unit

[0727] 110: Ammonia storage tank 120: Ammonia supply pump

[0728] 130: Buffer tank 140: Ammonia pressurization pump

[0729] 150: Ammonia vaporizer 160: Ammonia main supply valve

[0730] 200: Waste heat recovery unit

[0731] 210: Preheater 220: Waste heat recovery device

[0732] 230: Supercritical turbine 240: Recuperator

[0733] 250: Pre-cooler 260: Supercritical compressor

[0734] 270: Heat recovery cooler 280: Heat source supply valve

[0735] 290: Heat source branch valve

[0736] 300: Heat source supply section

[0737] 310: Heat medium tank 320: Heat medium circulation pump

[0738] 330: Heat medium heater

[0739] 400: Ammonia condenser

[0740] 410: Ammonia compressor 420: Ammonia condenser

[0741] 430: Receiver 440: Cooling recovery device

[0742] 450: Gas receiver 460: Emergency stop valve

[0743] 470: Ammonia detection unit 480: Ammonia discharge valve

[0744] 490: Check valve

[0745] 500: Ammonia treatment unit

[0746] 510: Separator 520: Absorber

[0747] 530: Drain tank 540: Ammonia bilge tank

[0748] 550: Clean drain tank 551: Drain temperature measuring unit

[0749] 560: Chiller 570: Clean drain pump

[0750] 700: Gas fuel supply unit 600: LNG storage tank

[0751] 710: Fuel supply pump 720: Gas fuel compressor

[0752] 730: Fuel pressure pump 740: Fuel carburetor

[0753] 750: Gas fuel main supply valve 760: Vaporization heat source valve

[0754] 800: Reliquefaction Department

[0755] 810: Evaporative gas compressor 820: Refrigerant circulation device

[0756] 830: Reliquefaction device

[0757] GT: Gas Turbine

[0758] CF: Combustion air filter VF: Air filter

[0759] CI: Combustion air intake duct VI: Ventilation air intake duct

[0760] CO: Combustion air exhaust duct VO: Ventilation air exhaust duct

[0761] T: Turbine G: Generator

[0762] FN: Ventilation fan

[0763] GE: Generator Engine

[0764] BR: Boiler VM1, VM2: Vent Mast

[0765] FL: Ammonia supply line BL: Ammonia evaporation gas line

[0766] RL: Ammonia reliquefaction line GL: Gas fuel supply line

[0767] LL: Forced vaporization line TL: Reliquefaction recovery line

[0768] CL: Tank cooling line DL: Ammonia discharge line

[0769] EL: Exhaust gas line HL: Heat medium circulation line

[0770] HL1: Steam heating line HL2: Steam branch line

[0771] HL3: Heat source supply line HL4: Vaporization heat source line

[0772] HL5: Heat medium vaporization line PL: Purging gas condensation line

[0773] SL: Supercritical Line SL1: Supercritical Branch Line

[0774] A: Stern area F: Bow area

[0775] E: Engine room area U: Chimney

[0776] P: Ammonia fuel preparation room C: Cargo compressor room

[0777] D: Outer deck Q: Cabin area

[0778] QC: Air conditioning unit< / als>

Claims

1. A gas turbine that generates electricity using gaseous ammonia as fuel; Ammonia storage tank for storing ammonia in liquid state; An ammonia fuel supply unit for supplying gaseous ammonia fuel to the above gas turbine; An ammonia condenser for condensing ammonia evaporation gas generated in the ammonia storage tank and recovering it to the ammonia storage tank; An ammonia treatment unit for treating ammonia in the purging gas generated while purging at least one of the ammonia fuel supply unit and the ammonia condenser unit; A waste heat recovery unit that generates electricity by recovering waste heat from exhaust gas discharged from the gas turbine while circulating supercritical carbon dioxide; and An ammonia gas turbine fuel supply system, comprising: a heat source supply unit that supplies heat energy or steam heat energy generated in the waste heat recovery unit to the ammonia fuel supply unit.

2. In claim 1, The above gas turbine is a dual-fuel gas turbine that selectively uses ammonia and liquefied gas as fuel. The above ammonia gas turbine fuel supply system, A liquefied gas storage tank for storing the liquefied gas in a liquid state; and An ammonia gas turbine fuel supply system, comprising: a gas fuel compressor for compressing evaporated gas of liquefied gas generated by natural vaporization of liquefied gas in the liquefied gas storage tank and supplying the evaporated gas to the gas turbine.

3. In claim 2, An ammonia gas turbine fuel supply system further comprising a cold heat recovery device for cooling the ammonia by heat exchange with the evaporated gas of the ammonia and the liquefied gas supplied to the gas fuel compressor and recovering the ammonia into an ammonia storage tank.

4. In claim 2, Further comprising a generator engine that generates electric power by receiving gas fuel from the above gas fuel compressor; An ammonia gas turbine fuel supply system, wherein the above generator engine generates electric power equivalent to a load exceeding the output of the gas turbine.

5. In claim 2, The above gas turbine, Below the first load, the gas fuel is used as fuel to generate electricity, An ammonia gas turbine fuel supply system that generates electricity by using at least one of ammonia and gas fuel as fuel when the first load is greater than or equal to the first load and less than or equal to the second load.

6. A step of vaporizing and heating ammonia stored in a liquid state to produce gaseous ammonia; A step of generating electricity by burning the above-mentioned gaseous ammonia to drive a gas turbine and using the generated electricity as propulsion energy; A step of generating electricity by recovering waste heat from exhaust gas discharged from the gas turbine while circulating supercritical carbon dioxide; A step of condensing and recovering ammonia evaporation gas generated by natural vaporization of ammonia stored in the above liquid state without supplying it to the gas turbine; A step of recovering the residual heat or steam energy of the supercritical carbon dioxide and supplying it to the step of generating the gaseous ammonia; When the mode in which the gas turbine is supplied with gaseous ammonia as fuel is stopped, a step of purging at least one of the pipes through which the gaseous ammonia is supplied to the gas turbine and the pipes through which the ammonia evaporation gas is condensed and recovered; and A method for supplying ammonia gas turbine fuel to a ship, further comprising a step of absorbing ammonia in the purging gas generated in the above purging step.

7. In claim 6, A method for supplying ammonia gas turbine fuel to a ship, wherein the gaseous ammonia supplied to the gas turbine is entirely combusted in the gas turbine without being recovered or discharged from the gas turbine.

8. In claim 6, It further includes a step of supplying the evaporated gas generated by naturally vaporizing the liquefied gas using the above gas turbine as fuel; A method for supplying fuel to an ammonia gas turbine of a ship, wherein the gas turbine generates electricity by selectively using the ammonia and the evaporated gas, either individually or in combination, as fuel.

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