Use of Hydrogen and Liquid Natural Gas Hybrid Fuels in Marine Applications to Reduce Carbon Footprint

Abstract

A method of operating a marine vessel includes supplying hydrogen or a fuel mixture including hydrogen and a hydrocarbon fuel to a generator located on the vessel and supplying power to an electrical load of the vessel from the generator.

Description

[Technical Field]

[0001] This disclosure relates generally to marine power generation systems, and more particularly to hydrogen-fueled power generation systems. [Background technology]

[0002] The shipping industry is preparing to meet new IMO (International Maritime Organization) targets of a 40% emissions reduction by 2030. The shipping industry is seeking solutions to achieve short- and long-term emissions reduction targets for new and existing ships. There are over 100,000 existing ships that need to catch up to IMO requirements. Summary of the Invention

[0003] In one embodiment, a method of operating a marine vessel includes supplying hydrogen or a fuel mixture including hydrogen and a hydrocarbon fuel to an electrical generator located on the vessel, and supplying electrical power to an electrical load of the vessel from the electrical generator.

[0004] In another embodiment, a marine vessel comprises a hull, a deck, an electrical load, a hydrogen tank, and a generator configured to receive hydrogen from the hydrogen tank or a fuel mixture comprising hydrogen and a hydrocarbon fuel and to power the electrical load.

[0005] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the general description above and the detailed description below, serve to explain features of the invention. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram of a marine vessel including a hybrid power system according to various embodiments of the present disclosure. [Figure 2] FIG. 2 is a flowchart illustrating steps in a method for controlling emissions of a vessel according to various embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0007] Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References to specific examples and implementations are made for illustrative purposes and are not intended to limit the scope of the invention or the claims.

[0008] When an element or layer is referred to as being "on" or "connected to" another element or layer, it is understood that the element or layer can be directly on or connected to the other element or layer, or that there can be intervening elements or layers. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element or layer, there are no intervening elements or layers. For purposes of this disclosure, it is understood that "at least one of X, Y, and Z" can be interpreted as X only, Y only, Z only, or any combination of two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ).

[0009] Where a range of values ​​is presented, unless the context clearly dictates otherwise, it is understood that each value between the upper and lower limits of that range, to one decimal place of the lower limit's unit, and any other stated or intervening value in that stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included within the smaller ranges and are also encompassed within the invention, subject to any specifically excluded limit within the stated range. When a stated range includes one or both of the limits, ranges excluding either or both of those included limits are also encompassed within the invention. It is also understood that the term "about" may refer to minor measurement errors, for example, 5% to 10%. Additionally, as used herein, weight percent (wt%) and atomic percent (at%) refer to percent by total weight or percent by total number of atoms, respectively, of the corresponding composition.

[0010] Words such as "then," "then," and "next" are not necessarily intended to limit the order of steps, but rather these words may be used to guide the reader through the method description. Further, any reference to a claim element in the singular, for example, using the article "a," "an," or "the," should not be construed as limiting that element to the singular.

[0011] In one embodiment shown in FIG. 1 , a method of operating a vessel (i.e., a watercraft) 10 includes using a fuel including pure hydrogen or a mixture of hydrogen and another fuel to power a marine vessel. The terms "vessel" and "ship" are used interchangeably herein. A vessel or ship may transport cargo and / or passengers. The vessel 10 may include a hull 12 and a deck 14. The vessel 10 may also include a bridge 16. In one embodiment, the vessel 10 may be a marine vessel configured to operate in seas and oceans. However, vessels 10 configured to operate in rivers and lakes may also be used.

[0012] In one embodiment, hydrogen is stored on board the vessel. In another embodiment, hydrogen is generated on board the vessel by electrolysis. For example, hydrogen is generated by a solid oxide electrolysis cell (i.e., a solid oxide electrolyzer). In one embodiment, a mixture of hydrogen and liquid natural gas is used to power the vessel. The mixture may contain 10 to 90 percent hydrogen by volume. In one embodiment, the fuel is supplied to a solid oxide fuel cell power generation system to generate electricity for the vessel.

[0013] Various embodiments of the present disclosure have application throughout the marine sector to use a blend of various fuel types, with or without existing diesel fuel, to reduce carbon (e.g., greenhouse gas) emissions. For example, various embodiments provide a marine hybrid power system that utilizes hydrogen to reduce the carbon emissions of a vessel.

[0014] 1 is a schematic diagram of a vessel 10 including a vessel power system 100 according to various embodiments of the present disclosure. In one embodiment, the vessel 10 may include a marine vessel, and the vessel power system 100 may include a marine vessel power system located within a hull 12 and / or on a deck 14 of the vessel 10. Referring to FIG. 1 , the power system 100 may include an optional fuel tank 102, a hydrogen tank 104, a fuel valve 106, an energy storage device 108, a generator (i.e., electrical generator) 110, an optional hydrogen generator 114, and a controller 120.

[0015] The fuel tank 102 may be configured to store a hydrocarbon fuel, such as liquefied natural gas (LNG), marine diesel, or the like. However, the present disclosure is not limited to any particular type of hydrocarbon fuel. In one embodiment, the fuel tank 102 may be omitted if the vessel is configured to operate solely on hydrogen as fuel. The hydrogen tank 104 may be configured to store hydrogen (H), which may be generated on board or supplied from an external source, such as a container ship or port generation or storage facility. The hydrogen tank may be a gas storage cylinder, which may optionally include a hydrogen storage medium that absorbs hydrogen.

[0016] Hydrogen produced via a conventional steam methane reforming (SMR) reaction process is believed to result in the generation of significant carbon emissions. Therefore, in some embodiments, the hydrogen supplied to the hydrogen tank 104 may be "green hydrogen" generated using low-carbon power sources, such as solar, wind, hydroelectric, or nuclear power, to reduce overall carbon emissions.

[0017] In various embodiments, the fuel tank 102 and / or the hydrogen tank 104 may include pumps and / or flow control valves (e.g., two-way valves) to control the flow rates of hydrogen and hydrocarbon fuel supplied to the fuel valve 106 and / or the generator 110 via respective fuel flow conduits (e.g., pipes or manifolds) 103 and hydrogen flow conduits (e.g., pipes or manifolds) 105. The fuel valve 106 may be a three-way valve configured to control the hydrogen-to-hydrocarbon ratio of the fuel supplied to the generator 110 via the inlet flow conduit (e.g., pipe or manifold) 107.

[0018] The energy storage device 108 may include any device configured to store electrical energy, such as a battery (e.g., a battery bank), a supercapacitor, a flywheel, etc. The energy storage device 108 may be electrically connected to the load power bus 111 by an electrical connection (e.g., a power bus) 113.

[0019] The generator 110 may be an electric generator configured to power the vessel's onboard electrical loads 112, such as the propulsion system and / or general electrical loads, using an electrical power bus 111. In some embodiments, the generator 110 may be a combustion-type generator, such as a turbine or a reciprocating piston engine. In other embodiments, the generator 110 may be a fuel cell system, such as a solid oxide fuel cell (SOFC) system. In still other embodiments, the generator 110 may include both a fuel cell system and a combustion-type generator, such as a turbine or a reciprocating piston engine. The generator 110 may be configured to operate using a hydrocarbon fuel stored in the fuel tank 102, hydrogen stored in the hydrogen tank 104, or a mixture thereof.

[0020] A marine vessel may have various operating modes, such as a cold start mode, a port mode, a sailing / steering mode, and a loading / unloading mode. The magnitude of the load 112 applied to the generator 110 may vary for each mode. In addition, local and international emission requirements may impose unique constraints on the operation and / or emissions of the vessel. For example, carbon emission limits may be lower near shore and / or in port than in the open sea. In addition, carbon emission limits may vary for each operating mode.

[0021] Thus, the controller 120 may be a central processing unit or the like configured to control the operation of the power system 100 based on an operating mode and / or applicable emission limits. For example, the controller 120 may be configured to control the energy storage device 108, the generator 110, the hydrogen generator 114, and / or the fuel valve 106 based on the size of the load 112 and / or applicable carbon emission limits.

[0022] For example, in some embodiments, the controller 120 can be configured to add hydrogen to a hydrocarbon fuel to form a fuel mixture configured to reduce the vessel's carbon emissions in order to comply with local authority or international emission requirements having jurisdiction. The controller 120 can be configured to adjust the fuel valve 106 to control the relative amounts of hydrogen and hydrocarbon fuel included in the fuel mixture delivered to the generator 110. In some embodiments, the fuel mixture delivered to the generator can include between about 0 volume percent and about 90 volume percent (vol.%), e.g., between about 10 vol.% and about 90 vol.%, of hydrogen, and between about 100 vol.% and about 10 vol.%, e.g., between about 90 vol.% and about 10 vol.% of hydrocarbon fuel.

[0023] For example, the controller 120 may be configured to determine an amount of hydrogen to be mixed with a hydrocarbon fuel to form a fuel mixture configured to minimize overall fuel costs while meeting the emission requirements of a given jurisdiction. For example, because hydrogen may currently be more expensive to produce than hydrocarbon fuels such as LNG, the controller 120 may be configured to utilize only the amount of hydrogen necessary to meet applicable emission requirements, such as carbon emission requirements, when forming the fuel mixture. In various embodiments, the controller 120 may utilize the vessel's global positioning system (GPS) coordinates and a lookup table to determine the emission requirements currently applicable to the vessel.

[0024] In some embodiments, for example, when power requirements are relatively low, such as when the vessel 100 is operating in a port mode, the controller 120 may be configured to utilize power stored in the energy storage device 108 and / or power provided by port electrical utilities to power the loads 112. In the alternative, hydrogen provided by the port utilities (e.g., flexible hose connections) may be used to operate the generators 110 to power the loads 112.

[0025] In some embodiments, the power system 100 can optionally include a hydrogen generator 114. For example, the hydrogen generator 114 can include a solid oxide electrolysis cell (SOEC) system configured to produce hydrogen by water electrolysis. For example, the hydrogen generator 114 can operate using power provided by the generator 110 and / or power provided by port facilities. For example, while in port, the vessel can be powered by onshore green energy sources, such as solar, wind, tidal, or nuclear power sources. In some embodiments, the generator 110 can be used to power the hydrogen generator 114 via an electrical connection (e.g., a power bus) 115, for example, while navigating an area with less restrictive emission requirements. Hydrogen generated by the hydrogen generator 114 can be supplied to the hydrogen tank 104 via a hydrogen inlet conduit (e.g., a pipe or manifold) 117 connecting the outlet of the hydrogen generator 114 to the inlet of the hydrogen tank 104. During operation of the vessel 10 in locations requiring reduced carbon emissions, stored hydrogen may be supplied from the hydrogen tank 104 via conduit 105 to the generator 110 .

[0026] FIG. 2 is a flowchart illustrating steps of a method for operating the marine vessel 10 with the hybrid power system 100 shown in FIG. 1 , according to various embodiments of the present disclosure. Referring to FIGS. 1 and 2 , in step 200, a carbon emission limit for the marine vessel 10 may be determined. For example, the controller 120 may identify applicable jurisdictional carbon emission regulations based on the current location of the vessel, which may be determined based on the vessel's GPS coordinates. The carbon emission limit may be determined based on the vessel's current operating mode and / or corresponding carbon emission limits and / or emission rates set forth in the applicable emission regulations. The emission regulations may include regional emission regulations and / or International Maritime Organization targets. In an alternative, the carbon emission rate may be manually set by the vessel operator.

[0027] A current carbon emission rate may be determined in step 202. For example, the carbon emission rate may be determined based on the current hydrocarbon fuel consumption by the vessel and the corresponding carbon emission rate.

[0028] In step 204, the controller 120 may compare the current carbon emission rate to the established carbon emission limit to determine whether the current carbon emission is below the emission limit and therefore acceptable. If the carbon emission rate is lower than the established carbon emission limit, the method may return to step 200. If the carbon emission rate exceeds the emission limit, the method may proceed to step 206.

[0029] In step 206, the controller 120 may calculate a hydrogen-to-hydrocarbon fuel ratio based on the determined carbon emission limits and the vessel's current power requirements (e.g., the vessel's current operating mode power load). For example, the controller 120 may increase the hydrogen-to-hydrocarbon fuel ratio supplied to the generator 110 to form a fuel mixture configured to reduce carbon emissions. In particular, the controller 120 may determine the magnitude of the power demand of the load 112 based on the current operating mode, and then calculate the corresponding hydrogen-to-hydrocarbon fuel ratio and total flow rate of the fuel mixture based on the estimated power magnitude of the load 112.

[0030] For example, in some embodiments, the controller 120 can calculate the maximum amount of hydrocarbon fuel that can be used by the generator 110 without causing the carbon emissions of the generator 110 to exceed the carbon emission limit. The controller 120 can then calculate the corresponding hydrocarbon power output of the generator. The controller 120 can then calculate the amount of hydrogen needed to increase the power output of the generator by an amount equal to the difference between the hydrocarbon power output and the magnitude of the load. The controller 120 can then calculate the amount of hydrogen to add to the hydrocarbon fuel to form a fuel mixture configured to generate a sufficient amount of power to meet the power demand of the load 112 and carbon emissions that are lower than the carbon emission limit.

[0031] In some embodiments, the power generated by the generator 110 can be supplemented by power stored in the energy storage device 108, such that the amount of hydrocarbon fuel and / or hydrogen supplied to the generator 110 can be reduced. Thus, the controller 120 can calculate a hydrogen to hydrocarbon fuel ratio based on the state of charge of the device 108 and the corresponding reduction in the size of the load 112 due to the power supplied to the load 112 from the device 108.

[0032] In step 208, the controller 120 may adjust the flow rates of hydrogen and hydrocarbon fuel used to form the fuel mixture supplied to the generator 110 based on the calculated hydrogen-to-hydrocarbon fuel ratio. For example, the controller 120 may control the fuel valve 106 to adjust the relative hydrogen and hydrocarbon fuel flow rates to the generator 110 to achieve corresponding levels of carbon emissions and power output from the generator 110. In one embodiment, the generator 110 may operate solely on hydrogen fuel. In this case, the hydrogen-to-hydrocarbon fuel ratio is represented by a specific value or code to avoid division by zero.

[0033] In some embodiments, the generator 110 can include a SOFC system and the hydrocarbon fuel can be natural gas, such as liquid natural gas. The controller can control the fuel valve 106 to adjust the relative flow rates of hydrogen and hydrocarbon fuel (e.g., hydrogen-to-hydrocarbon fuel ratio) to the generator 110 to achieve a corresponding level of carbon emissions from the generator 110.

[0034] In various embodiments, the generator 110 may generate power in excess of the power demand of the load 112 while maintaining carbon emissions at a level below applicable carbon emission limits. In such situations, the controller 120 can provide excess power from the generator 110 to the hydrogen generator 114 and / or the energy storage device 108. The hydrogen generated by the hydrogen generator 114 can be stored in the hydrogen tank 104 for later use.

[0035] This approach provides a novel way to use a mixture of fuels tailored to the specific operating mode of a ship at the right time to reduce carbon emissions. The use of different fuel types can be used to reduce the emissions footprint of legacy and new ships or fleets.

[0036] The controller 120 described herein can be implemented using a computing device (such as a computer) that includes a programmable processor, memory, and other components that are programmed with instructions to perform certain functions, or can be implemented within a processor designed to perform certain functions. The processor can be any programmable microprocessor, microcomputer, or one or more multiprocessor chips that can be configured by software instructions (applications) to perform various functions, including those of the various embodiments described herein. In some computing devices, multiple processors can be provided. Typically, software applications can be stored in internal memory before being accessed and loaded into the processor. In some computing devices, the processor can have sufficient internal memory to store application software instructions.

[0037] The various illustrative logic blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the particular application and design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

[0038] The hardware used to implement the various example logic, logic blocks, modules, and circuits described in connection with the aspects disclosed herein may be implemented or performed using a controller that may be or include a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, such as a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Alternatively, some blocks or methods may be performed by circuitry that is specific to a given function.

[0039] The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use any of the described embodiments. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of the present disclosure. Accordingly, the claims are not intended to be limited to the embodiments shown herein, but are to be accorded the widest scope consistent with the language of the claims and the principles and novel features disclosed herein.

Claims

1. 1. A method of operating a marine vessel, comprising: determining carbon emission limits applicable to the vessel based on the vessel's current location; determining a magnitude of the electrical power demand of the vessel's electrical loads to be applied to a generator; calculating a hydrogen to hydrocarbon ratio based on the carbon emission limit and the magnitude of the power demand of the electrical load; forming a fuel mixture by adding hydrogen to a hydrocarbon fuel such that the fuel mixture has the calculated hydrogen to hydrocarbon ratio; supplying the fuel mixture comprising the hydrogen and the hydrocarbon fuel to a generator located on the vessel; supplying electrical power from the generator to the electrical loads of the vessel; The method comprising:

2. The method of claim 1 , wherein the hydrogen is stored on board the vessel.

3. 10. The method of claim 1, further comprising generating the hydrogen on board the vessel by electrolysis.

4. generating hydrogen on board the marine vessel includes generating the hydrogen from water using a solid oxide electrolysis cell; The method of claim 3 , wherein the solid oxide electrolysis cell is powered by the generator.

5. The method of claim 1 , wherein the generator comprises a solid oxide fuel cell power generation system and the vessel comprises a marine vessel.

6. The method of claim 1 , wherein the generator comprises a gas turbine or a reciprocating piston engine.

7. the fuel mixture comprises 10 volume percent to 90 volume percent hydrogen and 10 volume percent to 90 volume percent of the hydrocarbon fuel; The method of claim 1 , wherein the hydrocarbon fuel comprises natural gas.

8. 10. The method of claim 1, further comprising using electrical power stored on board the vessel to reduce the magnitude of the electrical power demand of the electrical load prior to calculating the hydrogen to hydrocarbon ratio.

9. Calculating the hydrogen to hydrocarbon ratio comprises: calculating the maximum amount of hydrocarbon fuel that can be used by the generator without causing the generator's carbon emissions to exceed the carbon emission limit and the generator's corresponding hydrocarbon power output; calculating an amount of hydrogen required to increase the power output of the generator by an amount equal to the difference between the hydrocarbon power output and the magnitude of the power demand of the electrical load; The method of claim 1 , comprising:

10. The hull and The deck and The electrical load and A hydrogen tank and a hydrocarbon fuel tank; a generator configured to receive hydrogen from the hydrogen tank or a fuel mixture comprising hydrogen and a hydrocarbon fuel and to provide power to the electrical load; Controller and Equipped with The controller determining carbon emission limits applicable to the vessel based on the vessel's current location; determining a magnitude of the electrical demand of the electrical load applied to the generator; calculating a hydrogen to hydrocarbon ratio based on the carbon emission limit and the magnitude of the power demand of the electrical load; determining a composition of the fuel mixture having the calculated hydrogen to hydrocarbon ratio; A vessel configured to:

11. a hydrogen generator electrically connected to the generator and configured to generate the hydrogen; a hydrogen inlet conduit connecting the outlet of the hydrogen generator to the inlet of the hydrogen tank; The watercraft of claim 10 further comprising:

12. 12. The marine vessel of claim 11, wherein the hydrogen generator comprises a solid oxide electrolysis cell.

13. The watercraft of claim 10 , wherein the generator comprises a solid oxide fuel cell power generation system and the watercraft comprises a marine vessel.

14. The marine vessel of claim 10 , wherein the generator comprises a gas turbine or a reciprocating piston engine.

15. The controller calculating the maximum amount of hydrocarbon fuel that can be used by the generator without causing the generator's carbon emissions to exceed the carbon emission limit and the generator's corresponding hydrocarbon power output; calculating an amount of hydrogen required to increase the power output of the generator by an amount equal to the difference between the hydrocarbon power output and the magnitude of the power demand of the electrical load; 11. The marine vessel of claim 10, configured to calculate the hydrogen to hydrocarbon ratio by:

16. The marine vessel of claim 10 , further comprising an energy storage device electrically connected to a power bus connecting the generator and the electrical load.

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