Methanol fuel supply system and method for operating methanol fuel supply system

Abstract

The present disclosure relates to a methanol fuel supply system (1) for supplying methanol fuel (2) to a marine fuel consumer (4). The system (1) comprises: a fuel storage tank (6) configured to contain methanol fuel (2) to be delivered to a fuel consumer (4); a first fuel pump (8) fluidly connected to the fuel storage tank (6) and to the fuel consumption device (4). The system (1) comprises a recovery tank (10) fluidly connected to the fuel consumption device (4), the recovery tank (10) configured to collect and recover methanol fuel (2) purged from the fuel consumption device (4). The present disclosure also relates to a method for operating a methanol fuel supply system (1).

Description

Technical Field

[0001] The present invention relates to a methanol fuel supply system for supplying methanol fuel to a marine fuel consumption device and a method for operating the methanol fuel supply system. More specifically, the present invention relates to a methanol fuel supply system for supplying methanol fuel to a marine fuel consumption device and a method for operating the methanol fuel supply system as defined in the preamble of the independent claims. Background Art

[0002] Methanol is one of the strategic fuels for achieving the ambitious decarbonization goals of the International Maritime Organization in the coming decades. The shipping industry plays a key role in the global economy, transporting people and goods worldwide. Ships contribute to the world's carbon dioxide emissions. In accordance with the Paris Agreement on climate change, strategies have been adopted to gradually reduce the greenhouse gas emissions of the shipping industry.

[0003] Methanol is also known as methyl alcohol and has the chemical formula CH3OH. Traditionally, methanol is made from fossil raw materials via syngas. Renewable methanol is produced from biomass, resulting in bio-methanol; or from captured CO2 and H2 produced from water by electrolysis via renewable electricity, resulting in electro-methanol. Compared with other fuels, depending on the raw material, methanol can reduce CO2 emissions by 65% to 95%. Therefore, the use of renewable methanol as a fuel is strategic for achieving the decarbonization goal of shipping. In addition, compared with other traditional fossil fuels, its combustion is sulfur-oxide-free.

[0004] Currently, methanol is used as a fuel for propulsion on methanol tankers. The current methanol fuel supply systems on the market are based on a two-pressure-stage supercharger, which pumps fuel from a service tank located on deck to a dual-fuel diesel engine at the required pressure, temperature, flow rate, and filtration level. When the dual-fuel engine operation mode is switched to diesel, methanol is removed by purging with compressed inert gas.

[0005] The existing configuration of the methanol fuel supply system based on two-pressure-stage supercharging also requires two heat exchangers for methanol conditioning and for removing excess heat input during pump recirculation in full recirculation mode. The equipment of two-pressure-stage supercharging can be skid-mounted.

[0006] The purged methanol collected in the service tank may be contaminated with oil from the engine. The design of the service tank is specifically defined to handle the purged methanol that may be contaminated with engine oil.

[0007] For the existing configuration of the fuel supply system, an external pump is used as a low-pressure pump.

[0008] Given the strategic role of methanol in decarbonization, it can be used as a propulsion fuel for more demanding vessels such as container ships. However, higher power engines may require a larger methanol fuel storage volume, which may be difficult to arrange on board. Therefore, a more compact and simplified on-board fuel handling system is needed. Summary of the Invention

[0009] As mentioned above, in the case of higher power engines, fuel storage tanks with a larger fuel storage volume may be required. However, considering that the deck may be used for other purposes depending on the type of vessel, it is not convenient or even infeasible to use large fuel storage tanks on the deck. Arranging the fuel storage tanks below the deck and inside the ship may require a dedicated explosion-proof safety area, namely the so-called ATEX area, which is an area compliant with ATEX workplace and / or equipment guidelines. Therefore, the traditional fuel supply system configuration based on an external low-pressure pump for supplying fuel to the engine may also require a dedicated explosion-proof safety area in the ship's midsection.

[0010] In existing solutions, an external low-pressure pump needs to be arranged to avoid cavitation. Therefore, the external low-pressure pump is positioned as close as possible to the service tank, and a minimum liquid level is required in the service tank relative to the inlet nozzle to reduce the risk of pump cavitation. Therefore, a fuel preparation room must be arranged close to the fuel service tank to accommodate the external low-pressure pump.

[0011] Although there are known solutions in the art, there is still a need to develop a methanol fuel supply system for supplying methanol fuel to a marine fuel consumption device and a method for supplying fuel to a marine fuel consumption device through the methanol fuel supply system, which overcomes or alleviates at least some of the disadvantages of the prior art.

[0012] Therefore, an object of the present invention is to mitigate, alleviate or eliminate one or more of the deficiencies and disadvantages identified above in the prior art and to solve at least the problems mentioned above.

[0013] Furthermore, an object of the present invention is to provide a methanol fuel supply system that simplifies the system layout and provides a more compact system compared to known systems.

[0014] Another object of the present invention is to provide a methanol fuel supply system that does not require numerous and complex components for proper operation.

[0015] A further object of the present invention is to provide a methanol fuel supply system that is safe for operators.

[0016] These objects are achieved by a methanol fuel supply system for supplying methanol fuel to a marine fuel consumption device and a method for supplying fuel to a fuel consumption device through the methanol fuel supply system according to the appended claims.

[0017] According to a first aspect, there is provided a methanol fuel supply system for supplying methanol fuel from a fuel storage tank configured to contain methanol fuel to a marine fuel consumption device. The system includes: a first fuel pump fluidly connected to the fuel storage tank and the fuel consumption device. Characteristically, the system includes: a recovery tank fluidly connected to the fuel consumption device; and a purge circuit configured to purge the fuel consumption device and / or the fuel supply system with an inert gas. The purge circuit is fluidly connected to the recovery tank, which is configured to collect and recover methanol fuel and inert gas during purging.

[0018] By incorporating a recovery tank in the system to receive the purged methanol fuel, there is no need for a fuel service tank, resulting in a more compact system that saves space on deck. Thus, the system is configured such that methanol fuel can be supplied to the fuel consumption device without being routed through a buffer tank (such as a day tank or service tank between the storage tank and the fuel consumption device).

[0019] The methanol fuel supply system includes components such as pipes and controllable valves, which are configured and adapted to cooperate together to supply methanol to the marine fuel consumption device. A plurality of marine fuel consumption devices can be arranged in parallel and supplied with methanol fuel by the methanol fuel supply system.

[0020] Methanol fuel can be supplied to the marine fuel consumption device via a pipe including a controllable valve. The marine fuel consumption device can consume methanol fuel by igniting and burning it. The energy released from methanol combustion can be used as energy for propelling the ship and / or other uses, such as steam generation in boilers and auxiliary power generation devices. Methanol fuel can be maintained and stored in the storage tank in liquid form. The tank can completely contain the methanol fuel, or only a part of the tank can contain the methanol fuel. The tank can operate at ambient temperature. The tank can be pressurized from atmospheric pressure to about 0.2 bar, for example, by covering it with an inert gas (such as nitrogen).

[0021] Methanol fuel can be supplied to the fuel consumption device via a main fuel pipe that fluidly connects the fuel storage tank to the fuel consumption device. The first fuel pump can be connected to the main fuel pipe. Thus, the first fuel pump can be fluidly connected to the fuel storage tank and the fuel consumption device. The first fuel pump can be designed to suck methanol fuel from the fuel storage tank and convey the fuel along the main fuel pipe.

[0022] The recovery tank is configured to receive the purged methanol and the inert gas used for purging. Additionally, during purging, any contaminants, such as lubricating oil residues from fuel-consuming devices in the system, can be received in the recovery tank. The recovery tank is used to collect the purged methanol, inert gas, and contaminants, and is used to separate the inert gas used for purging. The recovery tank is not configured to receive methanol directly from the storage tank. Thus, the recovery tank is not used as a buffer, i.e., it is not configured to store, for example, an amount sufficient for daily use. The recovery tank can also be configured to separate the inert gas and contaminants from the methanol and recover the methanol. The separation can occur, for example, by sedimentation of different phases, but is not limited thereto. When a high liquid level in the recovery tank is detected and the fuel-consuming device is operating on methanol, the methanol can be transferred from the recovery tank to the main fuel pipeline. For this reason, the recovery tank can be designed to have a volume and dimensions that allow it to be installed in a limited area on a ship. The volume and dimensions of the recovery tank can be smaller than those of the service tank. The recovery tank can include an exhaust arrangement for discharging excess inert gas. The purged methanol is collected in the recovery tank in the fuel supply system, and thus the need for a dedicated service tank design for separating contaminants in the purged methanol is avoided. This will simplify the system and provide a more compact system than known systems. Additionally, such a system will not require numerous and complex components to operate correctly. This also provides a system that is safe for the operator.

[0023] The system further includes a purge circuit that is fluidly connected to the fuel-consuming device and the recovery tank, and the purge circuit is configured to remove the methanol fuel and any contaminants in the methanol fuel from the fuel-consuming device to the recovery tank by an inert gas. The purge circuit can be hydraulically connected to the main fuel pipeline and can include an inert gas source and is designed to supply the inert gas to the methanol fuel supply system. The purge pipeline can connect the inert gas source to the main fuel pipeline, and the purge pipeline can be connected to the fuel valve train of a marine internal combustion engine. The inert gas source can be the inert gas pipeline network of the ship on which the fuel supply system is installed. This inert gas pipeline network can be hydraulically connected to the main fuel pipeline. Alternatively, the inert gas source can include one or more dedicated containers, each containing a predetermined amount of inert gas.

[0024] The purge circuit can also be used for leak testing after maintenance of the fuel supply system and for reducing any oxygen content in the fuel supply system before filling the fuel supply system with a methanol-based fuel. Thus, the possibility of generating a combustible atmosphere in the fuel supply system is reduced. Eventually, a critical concentration is reached below which ignition cannot occur. The purge circuit can avoid this defect by creating a non-combustible atmosphere in the main fuel pipeline and any other pipelines connected to the main fuel pipeline.

[0025] Inerting can be performed at the first startup of the fuel supply system and at each startup after maintenance to remove air and / or oxygen from the pipeline. Before performing maintenance operations on the fuel supply system, a purging operation can also be performed by pushing the methanol-based fuel back into the fuel storage tank or the recovery tank through one or more discharge pipelines to avoid contact with air and also with the operator.

[0026] The purge circuit can be provided with one or more nitrogen inlets with filters, one or more pressure indicators and transmitters, one or more discharge valves, and one or more discharge pumps. The purged methanol is collected in the recovery tank in the fuel supply system, thus avoiding the need for a dedicated service tank design for separating contaminants in the purged methanol. The separation function can be achieved in the recovery tank in the fuel supply system. The inert gas can be held in the inert gas tank.

[0027] The first fuel pump can be arranged inside the fuel storage tank. The first fuel pump can be configured to be submerged in the methanol fuel contained in the fuel storage tank and is thus fluidly connected to the fuel storage tank. Submerging the first fuel pump in the methanol fuel can solve the cavitation critical problem without the need for a residual minimum liquid level in the tank. Using a submerged pump can also solve the problem of installing an external low-pressure stage pump in a dedicated explosion-proof safety area inside the ship, which results in no restrictions on the location of the fuel preparation room.

[0028] The first fuel pump can be controlled by at least one control device. The first fuel pump can be controlled at a variable pressure, which can vary within a pressure range that allows proper operation of the downstream system or equipment. For example, the pressure range can be between 2 and 7 bar, and the storage temperature can vary between -20°C and 40°C, but is not limited thereto. The first fuel pump can be a centrifugal pump.

[0029] The system can also include a high-pressure section fluidly connected to the fuel storage tank and the fuel consumption device, and can include one or more of the following: a second fuel pump (which is a high-pressure pump), at least one heat exchanger configured to heat or cool the methanol temperature, one or more filters, an inert gas supply device, a transfer pump for properly transferring methanol from the recovery tank to the suction side of the high-pressure pump. According to the present disclosure, a single heat exchanger can be used to regulate the temperature of the methanol. The high-pressure section can also include a heat exchange medium circuit, which includes a heat exchange medium tank, a pump, and at least one heat exchanger configured to maintain the temperature of the heat exchange medium within a determined temperature range to heat or cool the methanol. This temperature can vary, for example, between 30 and 50°C, but is not limited thereto.

[0030] The recovery tank can be fluidly connected to the main fuel pipeline through a connecting pipeline, and the main fuel pipeline connects the storage tank and the first fuel pump to the fuel-consuming device. In this way, the recovered methanol can return from the recovery tank to the fuel supply system. Therefore, the system can also include a second fuel pump, which is arranged downstream of the first fuel pump and upstream of the fuel-consuming device and is fluidly connected to the fuel storage tank and the fuel-consuming device. The first fuel pump is designed to suck fuel from the fuel storage tank at a first pressure value and convey the fuel along the main fuel pipeline at a second pressure value, where the second pressure value is higher than the first pressure value. The first fuel pump can generate a low-pressure pumping stage, and the first fuel pump can be a low-pressure pump.

[0031] The second fuel pump can be placed downstream of the first fuel pump along the main fuel pipeline. The recovery tank can be connected to the main fuel pipeline upstream of the second fuel pump via a connecting pipeline. Therefore, the second fuel pump can be placed downstream of the connecting pipeline of the recovery tank on the main fuel supply pipeline. The recovery tank can be configured to separate methanol fuel, inert gas, and pollutants from each other and return the recovered methanol fuel to the fuel-consuming device, for example, via a connecting pipeline.

[0032] The second fuel pump can be configured to receive fuel from the first fuel pump at a second pressure value and supply the fuel along the main fuel pipeline at a third pressure value, where the third pressure value can be equal to or higher than the second pressure value. The third pressure value can be equal to the fuel operating pressure value required by the fuel-consuming device. The second fuel pump can be a high-pressure pump. It can be, for example, a centrifugal pump. However, if the first fuel pump has the ability to generate a pressure equal to or higher than the operating pressure value of the fuel required by the fuel-consuming device, the second fuel pump may be redundant. In this case, it may not be necessary to install a second fuel pump in the system.

[0033] The fuel-consuming device can be a dual-fuel-driven fuel-consuming device, which is configured to be driven by the main fuel in the first operating mode and by methanol fuel as an auxiliary fuel in the second operating mode. In the second operating mode, the methanol fuel is conveyed to the fuel-consuming device as an auxiliary fuel through the methanol fuel supply system. In the first operating mode, by closing the valve on the main fuel pipeline, the conveyance of the methanol fuel as an auxiliary fuel to the fuel-consuming device is shut off. In the first operating mode, the main fuel is conveyed to the dual-fuel-driven fuel-consuming device, and the dual-fuel-driven fuel-consuming device is driven by the main fuel. Depending on the type of the dual-fuel-driven fuel-consuming device, the main fuel can be heavy fuel oil or diesel or other types of marine fuel.

[0034] The dual-fuel diesel engine can be a marine dual-fuel internal combustion engine. The dual-fuel internal combustion engine can operate relying on an auxiliary fuel such as methanol fuel and a main fuel such as heavy fuel oil or diesel. A separate oil tank (such as a diesel tank) can be fluidly connected to the dual-fuel internal combustion engine.

[0035] The marine fuel consumption device can be a boiler. The boiler can be a methanol fuel boiler.

[0036] The fuel supply system described above can be configured to feed multiple parallel fuel consumption devices (such as multiple engines). In that case, the pressure at the outlet of the system components may be different, and parallel methanol supply pipelines can be installed. The supply pipelines may require dedicated heat exchangers and filters. In addition, another high-pressure pump can also be installed.

[0037] The system can include an additional separator arrangement configured to separate methanol fuel, inert gas, and contaminants in the recovery tank from each other. The separator arrangement can be configured to return the recovered methanol fuel to the fuel consumption device during a second operating mode. The purged methanol fuel, inert gas, and contaminants collected in the recovery tank can be separated from each other by the separator arrangement. The separator arrangement can be arranged near the recovery tank or arranged in the recovery tank. The separator arrangement can be a sedimentation arrangement or a precipitation arrangement and can be provided by the recovery tank. The separation arrangement can include a filter arrangement.

[0038] A skid-mounted assembly provided with a single frame can be arranged to support at least some components downstream of the fuel storage tank. The frame can be designed to be as compact as possible and can be easily connected to the fuel storage tank and / or the fuel consumption device. In this way, the fuel supply system can be easily installed in any environment, such as inside the ship and / or on the deck of the ship.

[0039] One of the components supported by the single frame can be the recovery tank. Since the recovery tank is not used as a buffer, that is, not as an intermediate memory between the storage tank 6 and the fuel consumption device 4, it can be smaller than the service tank. The recovery tank can be used only for purged methanol. The recovery tank can be used only for separating lubricating oil residues (engine-related waste) and / or inert gas for purging. In addition to the recovery tank, the single frame can also support other components, such as a second fuel pump and / or other components including the high-pressure section of the second fuel pump. At least some components of the high-pressure section can be included in the skid-mounted assembly, where the high-pressure section includes a second fuel pump (which is a high-pressure pump), a heat exchanger configured to raise or lower the temperature of methanol or ethylene glycol-water, one or more filters, an inert gas supply device, a pump for transferring methanol from the recovery tank, and a heat exchange medium circuit that includes a heat exchange medium tank, a pump, and a heat exchanger, and the heat exchanger is configured to maintain the temperature of the heat exchange medium within a determined medium temperature range. The temperature range can be, for example, between 30°C and 50°C, but is not limited to this. The temperature can be lower or higher than within this range.

[0040] The heat exchanger device can be connected to the main fuel pipeline and is configured to perform heat exchange with the methanol fuel to bring it to a temperature value within a predetermined temperature range. This temperature range is equal to the operating temperature range of the methanol fuel required by the fuel consumption device. The heat exchange medium can be an ethylene glycol aqueous solution stored in an ethylene glycol water tank.

[0041] The fuel filtration unit can be connected to the main fuel pipeline and is configured to filter the methanol fuel before it is supplied to the fuel consumption device. The fuel filtration unit can include a plurality of filter elements and a plurality of filter valves such that during the maintenance of one or more filter elements, the methanol fuel can be continuously filtered through the fuel filtration unit. The system can also include arrangements for temperature regulation, pressure regulation, flow monitoring, automatic purging of the fuel supply system itself, pre-filtration, and filter double-block - vent isolation. These arrangements and components can be controlled by at least one control device.

[0042] The ship can be a transport ship. The methanol fuel supply system or at least some components of the methanol fuel supply system can be arranged in the ship. The methanol fuel supply system or at least some components of the methanol fuel supply system can be arranged on the deck of the ship. The ship can include a dedicated explosion-proof safety area, and wherein, the dedicated explosion-proof safety area is configured to accommodate at least some components of the system. The dedicated explosion-proof safety area can be arranged in the ship and / or on the deck of the ship. Methanol is a flammable and toxic liquid, and in the event of a leak, a dangerously high vapor concentration may be reached in the main fuel pipeline. This can lead to a fire if the following conditions are met: the temperature of the methanol fuel is higher than the flash point; there is a certain concentration of oxygen in the methanol fuel; the fuel vapor / oxygen ratio is within a certain range; there is an ignition source with a high enough temperature and energy. The dedicated explosion-proof safety area can eliminate this risk.

[0043] According to another aspect, a method for operating a methanol fuel supply system according to the first aspect is provided, wherein the method includes the following steps: supplying methanol fuel to the fuel consumption device; closing the supply of methanol fuel to the fuel consumption device; starting a purge circuit fluidly connected to the fuel consumption device and a recovery tank for removing the methanol fuel and any contaminants in the methanol fuel from the fuel consumption device and / or the fuel supply system to the recovery tank through an inert gas. In this way, the main fuel supply to the fuel consumption device can be started to operate the fuel consumption device. The main fuel and the auxiliary fuel are different fuels and are transported from different fuel storage tanks. The supply of methanol to the fuel consumption device can be closed by closing one or a group of valves on the main fuel pipeline and placing the full-circulation supply system in the full-circulation mode. The start of the purge circuit can be automatically executed. The methanol fuel supply system is capable of receiving and processing the purged flow and flow rate. The methanol fuel supply system can also start and process the automatic purging of the fuel supply system.

[0044] The step of supplying methanol fuel as an auxiliary fuel from a methanol fuel supply system to a fuel consumption device to operate the fuel consumption device in a second operation mode may include: supplying methanol fuel as an auxiliary fuel through a first fuel pump disposed in a fuel storage tank, the first fuel pump being configured to be submerged in the methanol fuel contained in the fuel storage tank. Submerging the first fuel pump in the methanol fuel can solve the cavitation critical problem without a residual minimum liquid level in the tank. Using a submerged pump will also solve the problem of installing an external low-pressure stage pump in a dedicated explosion-proof safety area in a ship, which results in no restriction on the location of the fuel preparation room. The first fuel pump may be controlled by a control device.

[0045] The step of supplying methanol fuel as an auxiliary fuel from a methanol fuel supply system to a fuel consumption device to operate the fuel consumption device in a second operation mode may include: supplying methanol fuel as an auxiliary fuel from a methanol fuel supply system disposed in a dedicated explosion-proof safety area in a ship to a dual-fuel diesel engine as a fuel consumption device for propelling the ship. The dual-fuel diesel engine may be a marine dual-fuel internal combustion engine. The dual-fuel internal combustion engine may operate relying on an auxiliary fuel such as methanol fuel and a main fuel such as heavy fuel oil or diesel or other marine fuels. A separate oil tank (such as a diesel tank) may be fluidly connected to the dual-fuel internal combustion engine. The dedicated explosion-proof safety area may be disposed in and / or on the deck of the ship.

[0046] The effects and features of the second aspect and the third aspect are largely similar to the effects and features described above with respect to the first aspect. The embodiments mentioned with respect to the first aspect are largely compatible with the second aspect and the third aspect.

[0047] Those skilled in the art will clearly understand the additional objects, advantages, and novel features of the present invention through the following details and by practicing the present invention. Although the present invention is described below, it should be apparent that the present invention is not limited to the specifically described details. Those skilled in the art will recognize additional applications, modifications, and combinations in other fields after reading the teachings herein, which all fall within the scope of the present invention. Brief Description of the Drawings

[0048] The above objects and additional objects, features, and advantages of the present disclosure will be more fully understood by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure in conjunction with the accompanying drawings.

[0049] Figure 1 A methanol fuel supply system according to an example is schematically illustrated.

[0050] Figure 2 A methanol fuel supply system according to an example is schematically illustrated;

[0051] Figure 3 Schematically shows a methanol fuel supply system according to an example;

[0052] Figure 4 Schematically shows a ship including a methanol fuel supply system. Detailed implementation

[0053] The present disclosure will now be described with reference to the accompanying drawings, in which preferred exemplary embodiments of the present disclosure are shown. However, the present disclosure may be implemented in other forms and should not be construed as limited to the embodiments disclosed herein. The disclosed embodiments are provided to fully convey the scope of the present disclosure to those skilled in the art.

[0054] Figure 1 Schematically shows a methanol fuel supply system 1 according to an example. The methanol fuel supply system 1 is configured to supply methanol fuel 2 to a marine fuel consumption device 4. The fuel consumption device 4 may be a dual-fuel diesel engine. The system 1 includes: a fuel storage tank 6 configured to hold the methanol fuel 2 to be delivered to the fuel consumption device 4; and a first fuel pump 8 fluidly connected to the fuel storage tank 6 and the fuel consumption device 4 via a main fuel pipeline 34. The fuel is supplied to the fuel consumption device 4 by the first fuel pump without being transferred through a buffer tank (such as a day tank or a service tank). The first fuel pump 8 is disposed in the fuel storage tank 6 and is configured to be immersed in the methanol fuel 2 contained in the fuel storage tank 6. The system 1 further includes a recovery tank 10 fluidly connected to the fuel consumption device 4 via a purge circuit 16 and a connecting pipeline 32. The recovery tank 10 is configured to collect and recover the methanol fuel 2 purged from the fuel consumption device 4 and is smaller than the previously used service tank. The recovery tank does not act as a buffer or buffer tank between the storage tank 6 and the fuel consumption device 4. Therefore, the recovery tank is not configured to directly receive fuel from the storage tank 6 to store, for example, an amount of fuel corresponding to daily use. Instead, it can only be used to separate lubricating oil residues (engine-related waste) and / or inert gases (such as nitrogen) from the purge, and thus, it can be smaller than the previously used service tank or day tank located on the deck. The recovery tank may include a connection for sealing oil discharge.

[0055] The fuel consumption device 4 is a dual-fuel driven fuel consumption device configured to be driven by a main fuel 14 in a first operating mode and by the methanol fuel 2 as an auxiliary fuel in a second operating mode.

[0056] System 1 also includes the purge circuit 16 mentioned above, which is fluidly connected to the fuel consumption device 4 and the recovery tank 10, and the purge circuit 16 is configured to remove the methanol fuel 2 and any contaminants 17 in the methanol fuel 2 from the fuel consumption device 4 to the recovery tank 10 by an inert gas 18 (which can be nitrogen). This is done when the fuel consumption device switches to the main fuel mode. The skid-mounted assembly 22 supports the recovery tank 10, and at least some of the pipes, valves, and other equipment for the fluid connection between the storage tank 6 and the fuel consumption device 4 can be included in the assembly 22. The skid-mounted assembly is a module that can be delivered and installed as a retrofit for an existing ship.

[0057] The recovery tank 10 is configured to separate the methanol fuel 2, the inert gas 18, and the contaminants 17 in the recovery tank 10 from each other. The separation can be carried out by sedimentation, but the recovery tank 10 can also include a separator arrangement 20. The recovery tank is configured to return the recovered methanol fuel 2 to the fuel consumption device 4 when a high liquid level in the recovery tank is detected and the fuel consumption device is operating on methanol and the methanol is being consumed, i.e., during the second operating mode. The return can be performed, for example, by inert gas pressurization or by a pump. The recovered methanol fuel 2 returns to the fuel consumption device 4 through a connecting pipe 32 from the separator arrangement 20 to the main fuel pipe 34, and the main fuel pipe 34 connects the storage tank 6 and the first fuel pump 8 to the fuel consumption device through the fuel valve train 30. As mentioned above, the recovery tank may not be configured to receive fuel directly from the fuel storage tank 6. However, it can be connected to the main fuel pipe 34 via the pipe 32.

[0058] Figure 2 A methanol fuel supply system 1 according to another example is schematically shown. The system 1 according to this example includes a second fuel pump 12, which is arranged downstream of the first fuel pump 8 and upstream of the fuel valve train 30 and the fuel consumption device 4. The second fuel pump 12 is arranged downstream of the connection point between the connecting pipe 32 from the recovery tank 10 and the main fuel pipe 34. The second fuel pump 12 can be a high-pressure fuel pump. The second fuel pump 12 is arranged on the skid-mounted assembly 22.

[0059] Figure 3A more detailed view of a methanol fuel supply system 1 according to the present disclosure is schematically shown. The skid-mounted assembly 22 is arranged to support a plurality of components downstream of the fuel storage tank 6 of the system 1. The recovery tank 10 with an optional separator arrangement 20 and the second fuel pump 12 connected to the main fuel pipeline 34 are supported by the skid-mounted assembly 22. The skid-mounted assembly 22 can be connected to an inert gas source 36. In addition, the assembly can further include an ethylene glycol water tank 38, a methanol heat exchanger device 40, and a fuel filtration unit 42 including a plurality of filter elements 46. The filtration unit 42 can be equipped with a double block and bleed isolation to allow for clean operation under safe conditions. The methanol heat exchanger device 40 can be connected to the main fuel pipeline 34 and configured to perform a heat exchange with the methanol fuel to bring it to a value within a predetermined temperature range. The heat exchange medium can be an ethylene glycol aqueous solution stored in the ethylene glycol water tank 38. The ethylene glycol water pump 39 and the ethylene glycol water heat exchanger 41 are fluidly connected to the ethylene glycol water tank 38. The fuel filtration unit 42 can be connected to the main fuel pipeline 34 and configured to filter the methanol fuel before supplying it to the fuel consumption device 4. The components of the system 1 described above can be controlled by a control device 50. The components arranged downstream of the high-pressure pump 12 are included in a high-pressure section, which can be mounted on the assembly 22. The assembly 22 can be located in a fuel preparation room.

[0060] Figure 4 A ship 26 including a methanol fuel supply system 1 is schematically shown. The ship 26 can be a transport ship. The ship 26 includes a methanol fuel supply system 1 configured to supply methanol fuel 2 to a marine fuel consumption device 4 arranged on the ship 26. The high-pressure section of the fuel supply system can be mounted on the assembly 22 as shown in Figure 3 . The fuel consumption device 4 can be a dual-fuel diesel engine 4a. Instead of, or in combination with, the dual-fuel diesel engine 4a, the fuel consumption device 4 can be a boiler 4b or another marine diesel engine. The system 1 is arranged in a dedicated fuel preparation room 28 inside the ship 26. Alternatively or in combination, the system 1 can be arranged in a dedicated fuel preparation room 28 on the deck 48 of the ship 26. The storage tank 6 is placed on board in accordance with International Maritime Organization (IMO) regulations.

[0061] The present disclosure also relates to a method of supplying fuel to a marine fuel consumption device 4 through a methanol fuel supply system 1. The method includes the following steps: supplying methanol fuel 2 from the methanol fuel supply system 1 to the fuel consumption device 4 to operate the fuel consumption device 4; closing the supply of methanol fuel to the fuel consumption device 4; starting a purge circuit 16 fluidly connected to the fuel consumption device 4 and the recovery tank 10 to remove the methanol fuel 2 and any contaminants 17 in the methanol fuel 2 from the fuel consumption device 4 to the recovery tank 10 through an inert gas 18.

[0062] The step of supplying the methanol fuel 2 may include supplying the methanol fuel 2 to the fuel consuming device at least by a first fuel pump 8 arranged in the fuel storage tank 6, the first fuel pump 8 being immersed in the methanol fuel 2 contained in the fuel storage tank 6. The fuel is supplied to the fuel consuming device. The supply is suitably accomplished without passing through a buffer tank (such as a day tank or a service tank).

[0063] The step of supplying the methanol fuel may include supplying the methanol fuel 2 from a methanol fuel supply system 1 in a dedicated fuel preparation chamber 28 arranged in a ship 26 to at least one dual-fuel diesel engine as the fuel consuming device 4 for propelling the ship 26. The supply is arranged via a main fuel pipeline 34 connecting the storage tank 6 and the fuel consuming device 4. The fuel supply system may be configured to supply to a plurality of parallel fuel consuming devices simultaneously.

[0064] The above description of the embodiments is provided only for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the described variations. Various modifications and variations will be apparent to those skilled in the art. These embodiments are selected and described in order to best illustrate the principles and practical applications and thus enable those skilled in the art to understand the invention in its various embodiments and the various variations suitable for its intended use. Within the framework of the present disclosure, the components and features specified above may be combined between the different embodiments specified.

Claims

1. A methanol fuel supply system (1) for supplying methanol fuel (2) from a fuel storage tank (6) configured to contain methanol fuel (2) to at least one marine fuel consumption device (4), the system (1) comprising: A first fuel pump (8) fluidly connected to the fuel storage tank (6) and the fuel consumption device (4), characterized in that The system (1) includes a recovery tank (10) fluidly connected to the fuel consumption device (4), and A purge circuit (16) configured to purge the fuel consumption device (4) and / or the fuel supply system with an inert gas, the purge circuit being fluidly connected to the fuel consumption device and the recovery tank (10), and wherein The recovery tank (10) is configured to collect methanol fuel and inert gas (2) during purging.

2. The system (1) according to claim 1, wherein, The first fuel pump (8) is arranged in the fuel storage tank (6) and configured to be immersed in the methanol fuel (2) contained in the fuel storage tank (6).

3. The system (1) according to claim 1 or 2, comprising a high-pressure section fluidly connected to the fuel storage tank (6) and the fuel consumption device (4), and including one or more of the following: a second fuel pump (12) which is a high-pressure pump; at least one heat exchanger (40) configured to heat or cool the methanol temperature; one or more filters (46); an inert gas supply device (36); a pump or other pressurizing device for transferring liquid from the recovery tank (10); and a heat exchange medium circuit including a heat exchange medium tank (38), a pump (39) and at least one heat exchanger (41), the at least one heat exchanger (41) being configured to maintain the temperature of the heat exchange medium within a determined temperature range.

4. The system (1) according to claim 1, 2 or 3, wherein, The recovery tank (10) is fluidly connected to the main fuel pipe (34) through a connecting pipe (32), and the main fuel pipe (34) connects the storage tank (6) and the first fuel pump (8) to the fuel consumption device (4).

5. The system (1) according to any one of the preceding claims, wherein, The system (1) includes a second fuel pump (12) arranged downstream of the first fuel pump (8) and upstream of the fuel consumption device (4).

6. The system (1) according to claim 5, wherein, The recovery tank (10) is connected to the main fuel pipe (34) upstream of the second fuel pump (12) via the connecting pipe (32).

7. The system (1) according to any one of the preceding claims, wherein, The fuel consumption device (4) is a dual-fuel-driven fuel consumption device configured to be driven by a main fuel (14) in a first operating mode and by methanol fuel (2) as an auxiliary fuel in a second operating mode.

8. The system (1) according to any one of the preceding claims, wherein, The recovery tank (10) is configured to separate the methanol fuel (2), inert gas (18) and contaminants (17) from each other and return the recovered methanol fuel (2) to the fuel consumption device (4).

9. The system (1) according to any one of the preceding claims, wherein, A skid-mounted assembly (22) is arranged to support at least some components downstream of the fuel storage tank (6).

10. The system (1) according to claim 9, wherein, One of the components supported by the skid-mounted assembly provided with a single frame (24) is the recovery tank (10).

11. The system (1) according to any one of the preceding claims, wherein, The system is configured to supply the methanol fuel to the fuel consumption device without passing through a buffer tank, such as a day tank or service tank located between the storage tank (6) and the fuel consumption device (4).

12. The system (1) according to any one of the preceding claims, wherein, The recovery tank is configured to receive only purged methanol and / or inert gas used for purging.

13. The system (1) according to any one of claims 1 to 12, configured to feed a plurality of fuel consumption devices connected in parallel.

14. A method for operating a methanol fuel supply system (1) according to any one of the preceding claims, wherein the method comprises the following steps: Supplying methanol fuel (2) to at least one fuel consumption device (4); Closing the supply of methanol fuel to the fuel consumption device (4); Activating a purge circuit (16) fluidly connected to the fuel consumption device (4) and the recovery tank (10) for removing methanol fuel (2) and any contaminants (17) in the methanol fuel (2) from the fuel consumption device (4) and / or the fuel supply system (1) to the recovery tank (10) by means of an inert gas (18).

15. The method according to claim 14, wherein, The step of supplying methanol fuel (2) comprises: supplying methanol fuel (2) to the fuel consumption device by means of at least the first fuel pump (8) arranged in the fuel storage tank (6), the first fuel pump (8) being configured to be immersed in the methanol fuel (2) contained in the fuel storage tank (6), and wherein the fuel is supplied to the fuel consumption device without passing through a buffer tank, such as a day tank or service tank.

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