System for manufacturing fuel offshore

Abstract

A method and system for manufacturing fuel offshore includes an offshore ocean platform on which an ammonia manufacturing unit is mounted. The ammonia manufacturing unit may manufacture ammonia using raw materials including seawater procured from an adjacent ocean platform and electricity from an offshore wind turbine. The manufactured ammonia may subsequently be liquefied and transported to a location away from the ocean platform or transferred to a remote location via a subsea pipeline. A portion of the hydrogen produced as part of the ammonia manufacturing process may be utilized to operate a mounted combustion turbine, thereby driving a generator on the ocean platform to generate electricity.

Description

Detailed Description of the Invention

[0001] [Field of the Invention] The present disclosure generally relates to the production of fuel for power generation, and more specifically, to hydrogen production using offshore fuel production facilities.

[0002] [Background of the Invention] It is known to use natural gas mainly composed of methane (CH4) for heat generation and power generation. Specifically, natural gas may be burned in a combustion turbine as fuel to generate mechanical power that is converted into electricity by a generator. However, when natural gas is burned, carbon dioxide (CO2) is produced as a by-product. Since the environmental impact of greenhouse gases such as carbon dioxide is known, there is a desire to reduce carbon dioxide emissions during power generation by finding other fuels for combustion turbines. In this regard, the use of hydrogen as an alternative fuel to natural gas for power generation has been gaining support.

[0003] One of the difficulties in using hydrogen is that it is difficult to transport. Since hydrogen molecules are smaller in size compared to methane molecules, conventional pipelines used for methane transportation may not be suitable for hydrogen transportation. For this reason, it has been proposed to liquefy hydrogen using known liquefaction technologies in order to transport hydrogen in cryogenic storage tanks. However, one of the difficulties of liquefied hydrogen is that liquefied hydrogen has a much lower energy per volume than liquefied natural gas (LNG), and more liquefied hydrogen transportation is required to achieve the same energy output as LNG. One solution is to transport hydrogen in another form, namely liquefied ammonia (NH3). However, since ammonia in gaseous or liquefied state is toxic, handling and utilization are not easy due to the risk of exposure to the human body. [Brief Description of the Drawings]

[0004] To more fully understand the present disclosure and its features and advantages, the following description is to be read in conjunction with the accompanying drawings.

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Best Mode for Carrying Out the Invention

[0005] [Detailed Description] Disclosed herein are methods and systems for producing hydrogen fuel at an offshore marine platform, where liquefied ammonia is delivered and cracked to produce hydrogen gas, which may be delivered by pipeline to land for use as fuel in generating electricity, or may be used at the offshore platform to generate electricity. Specifically, an ammonia cracking system mounted on the marine platform is semi-permanently installed offshore. A liquefied ammonia storage unit may be disposed adjacent to the marine platform to deliver a large volume of liquefied ammonia to the marine platform for cracking. In one or more embodiments, a floating liquefied ammonia storage unit and a floating liquefied natural gas storage unit are disposed adjacent to the marine platform such that the produced hydrogen can be mixed with natural gas before combustion or pipeline transfer. In other embodiments, the hydrogen fuel production system includes an offshore marine platform having a water purification unit for purifying seawater recovered from an adjacent marine platform. The purified water is used within the mounted hydrogen production system to produce hydrogen. After producing nitrogen using the mounted nitrogen production system, the produced hydrogen and nitrogen are utilized on-site by the mounted ammonia production system to produce liquefied ammonia. In other embodiments, the hydrogen fuel production system includes an offshore marine platform having a methane treatment system for converting methane to hydrogen to generate electricity on the marine platform. In still other embodiments, the hydrogen fuel production system includes an offshore marine platform having a water purification unit for purifying seawater recovered from an adjacent marine platform. The purified water is used within the mounted hydrogen production system to produce hydrogen. A mounted carbon dioxide source supplies carbon dioxide for reacting with the produced hydrogen to produce synthetic methane within a methane production reactor disposed on the marine platform.

[0006] Referring to FIG. 1, the hydrogen fuel production system 10 includes an offshore marine platform 20, and the offshore marine platform 20 is arranged to receive liquefied ammonia from a liquefied ammonia storage unit 26 located on or adjacent to the offshore marine platform 20. In one or more embodiments, the liquefied ammonia storage unit 26 is a floating liquefied ammonia storage unit 26 moored adjacent to the marine platform 20 and arranged to transfer liquefied ammonia for processing into hydrogen gas fuel to the marine platform 20. The floating liquefied ammonia storage unit 26 may include a plurality of large-capacity storage tanks 28 for receiving liquefied ammonia delivered from a liquefied ammonia carrier 30. In some embodiments, the total storage capacity of the liquefied ammonia load of the liquefied ammonia carrier 30 is smaller than the total storage capacity of the liquefied ammonia in the liquefied ammonia storage unit 26 so that the liquefied ammonia storage unit 26 can be used as a recovery or collection location for storing a small amount of liquefied ammonia delivered by the liquefied ammonia carrier 30 in a large volume. Thus, the floating liquefied ammonia storage unit 26 has a first total liquefied ammonia storage capacity, and the liquefied ammonia carrier 30 has a second total liquefied ammonia storage capacity smaller than the first total liquefied ammonia storage capacity. In such a case, the floating liquefied ammonia storage unit 26 is used to collect a sufficient amount of liquefied ammonia on the floating liquefied ammonia storage unit 26 before pumping the liquefied ammonia from the floating liquefied ammonia storage unit 26 to the liquefied ammonia carrier 30, and the amount of liquefied ammonia collected on the floating storage unit 26 is larger than the total storage capacity of the liquefied ammonia carrier 30.

[0007] In one or more embodiments, the liquefied ammonia carrier 30 may be moored at a mooring facility 33 separated from the floating liquefied ammonia storage unit 26 and the marine platform 20. In such a case, a floating transfer terminal 31 may be used to transfer liquefied ammonia from the floating liquefied ammonia storage unit 26 to the liquefied ammonia carrier 30.

[0008] In one or more embodiments, the marine platform 20 may be a jack-up platform, semi-submersible platform, barge, floating ship, fixed platform, cylindrical platform, or tension moored platform that is fixed to the ocean floor or moored at only one location during a long deployment period. In other embodiments, the marine platform 20 may be a floating ship such as a barge or a ship that can be moored at a predetermined position during a long deployment period. Further, although the marine platform 20 and the floating liquefied ammonia storage unit 26 are shown separately, the marine platform 20 and the floating liquefied ammonia storage unit 26 may be integrally formed on either the marine platform 20 or the floating storage unit 26. In any case, the marine platform 20 and the floating storage unit 26 may be relocatable to supply hydrogen corresponding to a demand to consumers through ammonia intake, such as from a liquefied ammonia carrier 30 or the floating liquefied ammonia storage unit 26.

[0009] In one or more embodiments, the marine platform 20 includes at least one platform deck 21 and three or more platform legs 23, and each platform leg 23 has a first end 23a and a second end 23b. The platform deck 21 is disposed adjacent to the first end 23a of each platform leg 123 and is supported above the sea surface 25. The second end 23b of each platform leg 123 may be connected to the sea floor 27.

[0010] The hydrogen fuel production system 10 may include one or more seawater inlets 29 for sucking in seawater for use in the hydrogen production process. The seawater inlet 29 is not limited to a specific system for sucking in seawater. However, in one or more embodiments, one or more seawater inlets 29 may be disposed near the second end 23b of the platform leg 23 of the ocean platform 20 to suck in cold water from the adjacent water mass. On the other hand, in other embodiments, the seawater inlets 29 may be respectively disposed at positions near the sea surface 125 between the first and second leg ends 23a, 23b of the platform leg 23 to suck in warm water from the adjacent water mass. The vertical height of the seawater inlet 29 may be adjusted based on the season so that the seawater used for a specific process on the ocean platform 20 surely reaches the optimal temperature. In still other embodiments, a first plurality of seawater inlets 29 may be disposed adjacent to the second end 23b of one or more platform legs 23, and a second plurality of seawater inlets 29 may be spaced apart from the second end 23b of one or more platform legs 23. In other words, the first plurality of seawater inlets 29 may be at a first distance from the second end 23b of one or more platform legs 23, and the second plurality of seawater inlets 29 may be at a second distance from the second end 23b of one or more platform legs 23, and the second distance may be greater than the first distance. In some embodiments, the second distance may be at least twice the first distance so that the warm mixed water on the sea surface and the colder deeper water below can be utilized to use seawater in different thermoclines in the process on the ocean platform 20.

[0011] Arranged on the marine platform 20 is an ammonia cracking system 36. The ammonia cracking system 36 does not need to be limited to a system for a specific type of ammonia cracking. However, in FIG. 1, the ammonia cracking system 36 includes a cracking reactor 40 that produces hydrogen (H2) and nitrogen (N2) from liquefied ammonia delivered to the marine platform 20 by a liquefied ammonia carrier 30 and stored in a floating liquefied ammonia storage unit 26. In some embodiments, the ammonia cracking system 36 may also include a pretreatment unit 38 for converting liquefied ammonia to ammonia gas prior to cracking. In one or more embodiments, the pretreatment unit 38 may be an expansion valve, and the liquefied ammonia is converted to ammonia gas as it passes through the expansion valve. In one or more other embodiments, the pretreatment unit 38 may be a heat exchanger for heating the liquefied ammonia pumped from the floating storage unit 26, i.e., cryogenic ammonia. When heated, the liquefied ammonia is converted to ammonia gas. Thus, the pretreatment unit 38 may be regarded as a regasification unit for converting liquefied ammonia to ammonia gas. In any case, after gasification, ammonia is introduced into a cracking reactor 40 that produces a production gas mixture of hydrogen and nitrogen from the ammonia gas. Optionally, thereafter, the production gas mixture may be introduced into a hydrogen purification unit 42 mounted on the marine platform 20 to produce purified hydrogen from the production gas mixture.

[0012] At this point, the hydrogen produced, whether it is purified hydrogen or a production gas mixture, may be sent via a transfer system 44, such as the illustrated hydrogen gas pipeline 44, to an onshore or coastal location or terminal. Alternatively, or in addition, all or part of the hydrogen produced may be transferred to the installed power generation system and used for power generation on the offshore platform 20. In other words, a first portion of the hydrogen produced may be sent via the pipeline 44, while a second portion of the hydrogen produced may be utilized for power generation on the offshore platform 20. For this reason, in one or more embodiments, the offshore platform 20 may include one or more combustion turbines 48, and the one or more combustion turbines 48 burn at least a portion of the hydrogen produced to supply mechanical power that is converted into electricity by one or more generators 50. In this regard, the combustion turbines 48 are in fluid communication with the ammonia cracking system 36 or the hydrogen purification unit 42, either directly or indirectly, to utilize at least a portion of the hydrogen produced as fuel for the combustion turbines 148. The nitrogen from the hydrogen purification unit 42 may be released into the atmosphere. In addition, in one or more embodiments, the heat generated from the combustion turbines 48 may be utilized by the ammonia cracking system 36 as a heat source for the pretreatment unit 38 and / or the cracking reactor 40, or for other heating applications. Similarly, the electricity generated from the generators 50 may be utilized by the ammonia cracking system 36 to operate the ammonia cracking system 36. Alternatively, or in addition, a plurality of offshore wind turbines 51 near the offshore platform 20 may be electrically connected to the offshore platform 20 to supply electricity to the offshore platform 20 for performing various processes, and in some embodiments, the electricity may include electricity for the ammonia cracking system 36.

[0013] Referring to FIG. 2, an embodiment of the ammonia cracking system 36 is shown in more detail by a flow diagram. Specifically, a cryopump 54 is utilized to pump liquid ammonia along a flow line 57 from a cryogenic storage tank 28, which can be mounted, for example, on a floating liquid ammonia storage unit 26, to a cracking reactor 40. In one or more embodiments, the pretreatment unit 38 may be disposed along the flow line 57. In the illustrated embodiment of FIG. 2, the pretreatment unit 38 is shown as a heat exchanger 38 that is utilized to convert liquid ammonia to ammonia gas. The heat exchanger 38 includes a container 55 having a liquid ammonia inlet 56 and an ammonia gas outlet 58. Although not essential, as shown, in some embodiments, heat may be supplied to the heat exchanger 38 using the heated product gas mixture from the cracking reactor 40. In other embodiments, the heat to the heat exchanger 38 may be supplied from another source, such as combustion gas obtained from the operation of a combustion turbine 48. Further, although the heat exchanger 38 is shown as being separated from the cracking reactor 40, in other embodiments, the heat exchanger 38 may be integrally configured as part of the cracking reactor 40. In any case, the heat exchanger 38 is not limited to a particular type of heat exchanger. In the illustrated embodiment, the container 55 includes a heat exchange mechanism 60, such as tubes or flat plates, where heated nitrogen gas and heated hydrogen gas are introduced into the heat exchange mechanism 60 at an inlet 62 and discharged from the heat exchange mechanism 60 at an outlet 64.

[0014] Whether the pretreatment unit 38 is a heat exchanger, an expansion valve, or some other device, the ammonia gas from the pretreatment unit 38 is introduced into the cracking reactor 40 via the ammonia gas inlet 70. The cracking reactor 40 includes a reaction vessel 72 that dissociates ammonia gas within the reaction chamber 73. In one or more embodiments, the cracking reactor 40 may be a catalytic cracking reactor 40 in which a catalyst 74 is disposed therein. In one or more embodiments, the catalyst 74 may be a nickel or other metal catalyst, but may be any other type of catalyst. In any case, heat is supplied to the reaction chamber 73 by applying heat from the heat source 76 to the reaction vessel 72. In some embodiments, the heat from the heat source 76 may be applied via a heat exchanger 78 disposed adjacent to the reaction vessel 72. In one or more embodiments, the heat source 76 may be a heating coil or heating element disposed adjacent to the reaction vessel 72. It will be understood that the present disclosure is not limited to the specific types of cracking reactors described herein, nor is it limited to their individual components.

[0015] As is known in the art, by dissociating ammonia gas inside the cracking reactor 40, a production gas mixture of hydrogen and nitrogen is obtained, and the production gas mixture exits the cracking reactor 40 via the production gas outlet 80. In one or more embodiments, the production gas mixture exiting the cracking reactor 40 via the production gas outlet 80 may then be introduced into a hydrogen purification unit 82 for further processing. Specifically, the hydrogen purification unit 82 may include an inlet 84 in fluid communication with the production gas outlet 80 of the cracking reactor 40. In other embodiments, as shown, the production gas mixture from the cracking reactor 40 may first be utilized in the heat exchanger 38 to preheat the liquefied ammonia from the cryogenic storage tank 28 before the production gas mixture is introduced into the hydrogen purification unit 82.

[0016] In some embodiments, hydrogen purification unit 82 is more preferred, but it should be understood that the present disclosure is not limited to the use of a hydrogen purification unit. Further, the present disclosure is not limited to a particular type of hydrogen purification unit. Thus, hydrogen purification unit 82 may include, but is not limited to, a pressure swing adsorption (PSA) system having two or more pressure vessels each containing at least a nitrogen absorbent, a membrane separation system that separates hydrogen from nitrogen using the flow of a gas mixture through a membrane, an electrochemical separation system, and a distillation system.

[0017] In any case, the purified hydrogen exits the hydrogen purification unit 82 through outlet 86. In one or more embodiments, outlet 86 is in fluid communication with pipeline 44 either directly or indirectly through a booster unit 88 (see FIG. 1) arranged to increase the pressure of the purified hydrogen for delivery to another location via pipeline 44. In one or more other embodiments, outlet 86 may also be in fluid communication with one or more combustion turbines 48 mounted on the offshore platform 20, whereby a portion of the hydrogen produced can be utilized as fuel within the combustion turbines 48 to generate electricity and / or heat for use in the cracking process described herein.

[0018] In some embodiments, rather than transporting the hydrogen produced by ammonia cracking on land, all of the produced hydrogen may be burned in the combustion turbine 48 to generate electricity in the generator 50, or may be combusted, and this electricity may then be transmitted to a remote location via the transfer system 44, where the transfer system 44 may be an electrical cable. Alternatively, the transfer system may include both a pipeline for transporting a first portion of the hydrogen produced on the offshore platform 20 and an electrical cable for transmitting the electricity generated on the offshore platform 20 using a second portion of the hydrogen produced on the offshore platform 20. This may be desirable if the offshore platform 20 generates more electricity than is required for the cracking operations described herein. In such a case, the excess electricity may be transmitted to an onshore or coastal location together with the produced hydrogen for distribution and / or use.

[0019] Referring to FIG. 3, in one or more embodiments, in addition to the ammonia cracking system 36, the offshore platform 20 may further include an LNG regasification unit 96 and a mixing unit 98 arranged to receive hydrogen gas and gaseous natural gas to produce a mixed natural gas. In this regard, in addition to the liquefied ammonia storage unit 26 provided on the offshore platform 20, for example, the floating liquefied ammonia storage unit 26 shown to be moored adjacent to the offshore platform 20, a floating liquefied natural gas storage unit 90 may also be provided on the offshore platform 20. In the illustrated embodiment, the floating liquefied natural gas storage unit 90 is moored adjacent to the offshore platform 20 and has a large-capacity storage tank 92 for receiving liquefied natural gas (LNG1) delivered from an external supply source 94 such as a liquefied natural gas carrier. The amount of hydrogen in the delivered natural gas may be minimal, for example, less than 0.5% in some embodiments, less than 1% in other embodiments, or less than 3% in still other embodiments, etc. In still other embodiments, the ratio of hydrogen in the delivered natural gas is simply lower than the desired ratio of hydrogen in the mixed fuel. In any case, for this reason, the hydrogen fuel production system 10 includes a first pump for transferring the liquefied natural gas LNG1 delivered from the floating liquefied natural gas storage unit 90 to the offshore platform 20 by pumping it for mixing, and a second pump for transferring the liquefied ammonia delivered from the floating storage unit 26 to the offshore platform 20 by pumping it for ammonia cracking.

[0020] In some embodiments where mixing occurs on the marine platform 20, the marine platform 20 may have at least a first side 20a and a second side 20b, a floating liquefied ammonia storage unit 26 may be moored adjacent to the first side 20a of the marine platform 20, and a floating liquefied natural gas storage unit 90 may be moored adjacent to the second side 20b of the marine platform 20. In any case, the LNG regasification unit 96 is utilized to convert the delivered liquefied natural gas back into gaseous natural gas, and after conversion, the natural gas can be mixed with purified hydrogen in the mixing unit 98 to produce a mixed fuel with a higher hydrogen ratio than the ratio initially contained in the delivered LNG1. In other words, the delivered LNG1 may have a first ratio of hydrogen, and the mixed fuel (LNG2) may have a second ratio of hydrogen that is higher than the first ratio of hydrogen.

[0021] Thereafter, the mixed fuel can be sent to another location via the pipeline 44 and / or burned as fuel in the combustion turbine 48. In one or more embodiments, the purified hydrogen may be sent via the pipeline 44, while the mixed fuel may be utilized in the combustion turbine 48 on the marine platform 20. Since the combustion turbine 48 may not be evaluated or designed to burn purified hydrogen, although mixing is required on the marine platform 20, it will be understood that unmixed purified hydrogen may be desired and thus sent via the pipeline 44 as unmixed purified hydrogen.

[0022] In some embodiments, rather than transferring purified hydrogen or a blended fuel from the offshore platform 20, all of the hydrogen produced, whether or not it is blended, may be burned in the combustion turbine 48 to generate electricity with the generator 50, and this electricity may then be sent to a remote location via the transfer system 44, in which case the transfer system 44 may be an electric cable. Alternatively, the transfer system may comprise both a pipeline for transferring a first portion of the hydrogen (either purified hydrogen or a blended fuel) produced on the offshore platform 20 and an electric cable for transmitting the electricity generated on the offshore platform 20 using a second portion of the hydrogen mixed with the natural gas LNG1 produced and delivered on the offshore platform 20. This may be desirable if the offshore platform 20 generates more electricity than is required for the ammonia cracking operations described herein. In such a case, the excess electricity may be transmitted to an onshore or coastal location, along with the hydrogen produced and / or the natural gas blended, for distribution and / or use.

[0023] It will be appreciated that the above-described system is desirable because it moves the handling of the toxic ammonia away from areas where people live, reducing the risks associated with the handling of ammonia. Further, the above-described system provides a solution for the bulk transport and storage of ammonia in a hydrogen fuel production system prior to dissociation during hydrogen fuel production.

[0024] Referring to FIG. 4, another embodiment of the hydrogen fuel production system 110 is shown, in which the offshore platform 120 is located offshore and includes an ammonia production system 136 for the production of liquefied ammonia. The produced liquefied ammonia is then stored in large quantities in a liquefied ammonia storage unit 126 on or adjacent to the offshore platform 120. In one or more embodiments, the liquefied ammonia storage unit 126 is a floating liquefied ammonia storage unit 126 and may include a plurality of large-capacity storage tanks 128 for receiving the liquefied ammonia produced on the offshore platform 120. In the illustrated embodiment, the liquefied ammonia produced on the offshore platform 120 and stored in large quantities by the floating liquefied ammonia storage unit 126 can be transferred to a liquefied ammonia carrier 130 for transportation to other locations. Thus, the hydrogen fuel production system 10 includes a first pump for transferring the produced liquefied ammonia NH3 by pumping it from the offshore platform 20 to the floating storage unit 26.

[0025] In one or more embodiments, the marine platform 120 may be a jack-up platform, semi-submersible platform, barge, floating ship, fixed platform, cylindrical platform, or tension moored platform that is fixed to the ocean floor or moored in only one location during a long deployment period. In other embodiments, the marine platform 120 may be a floating ship such as a barge or a ship that can be moored in a predetermined position during a long deployment period. In other embodiments, the marine platform 120 may be a floating ship such as a barge or a ship. Further, although the marine platform 120 and the floating liquefied ammonia storage unit 126 are shown separately, the marine platform 120 and the floating liquefied ammonia storage unit 126 may be integrally formed on either the marine platform 120 or the floating liquefied ammonia storage unit 126. Electricity for ammonia production may be supplied to the marine platform 120 by the offshore wind turbine 51 disposed in the vicinity of the marine platform 120.

[0026] In one or more embodiments, the marine platform 120 includes at least one platform deck 121 and three or more platform legs 123, and each leg 123 has a first end 123a and a second end 123b. The platform deck 121 is disposed adjacent to the first end 123a of each platform leg 123 and is supported above the sea surface 125. The second end 123b of each platform leg 123 may be connected to the seabed 127.

[0027] The floating liquefied ammonia storage unit 126 and the offshore platform 120 may be spaced apart from each other. However, in one or more embodiments, since liquefied ammonia is produced without the need for intermediate storage, the floating liquefied ammonia storage unit 126 is moored in proximity to the offshore platform 120 so as to maintain a continuous flow of liquefied ammonia between the floating liquefied ammonia storage unit 126 and the offshore platform 120. Here, when the output of the ammonia production unit 136 is low, it is understood that at low output, it may not be possible to easily pump liquefied ammonia to a storage unit at a distance from the offshore platform 120 or directly to the liquefied ammonia carrier 130. In this regard, the floating liquefied ammonia storage unit 126 is desirable because it can be used as a recovery storage facility for the liquefied ammonia produced on the offshore platform 120 until a sufficient amount of liquefied ammonia is produced for transportation to another location by the liquefied ammonia carrier 130. In this regard, the floating liquefied ammonia storage unit 126 has a first total liquefied ammonia storage capacity, and the liquefied ammonia carrier 130 has a second total liquefied ammonia storage capacity that is smaller than the first total liquefied ammonia storage capacity.

[0028] In any case, the ammonia production system 136 produces liquefied ammonia using hydrogen (H2) and nitrogen (N2) procured on the offshore platform 120. In one or more embodiments, the offshore platform 120 includes a water purification unit 140, a hydrogen production system 142, and a nitrogen production system 146. The hydrogen production system 142 uses the purified water from the water purification unit 140 to produce hydrogen for use in the ammonia production system 136.

[0029] Although not limited to a particular water purification unit, in some embodiments, the water purification unit 140 utilizes reverse osmosis and includes a water purification container 152 having a first chamber 154 and a second chamber 156, with a semi-permeable membrane 158 disposed between the first chamber 154 and the second chamber 156. A seawater inlet 160 is provided in the first chamber 154, and a purified water outlet 162 is provided in the second chamber 156. The water purification unit 140 also includes a pump 164 for pressurizing seawater within the first chamber 154. The pump 164 is in fluid communication with a seawater intake 129 that draws in seawater for purification.

[0030] Referring again to FIG. 4, in one or more embodiments, the seawater intake 129 is disposed near the second end 123b of the platform leg 123 of the offshore platform 120 to draw in colder water from the adjacent water mass, while in other embodiments, the seawater intake 129 is disposed near the sea surface 125 between the first and second leg ends 123a, 123b of the platform leg 123 to draw in warmer water from the adjacent water mass.

[0031] The semi-permeable membrane 158 may be any membrane known for use in reverse osmosis, but in one or more embodiments, the semi-permeable membrane 158 may be a polyimide thin film (less than 200 nm) having a pore size of about 0.0001 microns, adhered on top of a polysulfone porous layer (about 50 microns) on a non-woven support sheet. The drawn-in seawater is pumped to the water purification unit 140, where the water purification unit 140 is utilized to at least partially purify the pumped seawater to produce purified water, and then the hydrogen production system 142 is used to generate hydrogen gas from the purified water. In one or more embodiments, a purified water storage container 166 is fluidly disposed between the purified water outlet 162 of the water purification unit 140 and the hydrogen production system 142.

[0032] Referring to FIG. 6, although not limited to a specific hydrogen production system, in some embodiments, hydrogen production system 142 utilizes electrolysis for hydrogen production. Thus, in the illustrated hydrogen production system 142, a hydrogen production vessel 170 is provided having a first chamber 172 and a second chamber 174, with a membrane 176 disposed therebetween. Although not limited to a specific type of membrane, in one or more embodiments, membrane 176 is a proton exchange membrane (PEM) or an alkaline membrane. However, other membranes may also be utilized. In any case, the purified water 177 obtained from the water purification unit 140 is delivered to the hydrogen production vessel 170 via a purified water inlet 178 provided in the hydrogen production vessel 170. An anode assembly 180 having an anode 182 extending into the first chamber 172 is provided on a first side 176a of the membrane 176, and a cathode assembly 184 having a cathode 186 extending into the second chamber 174 is provided on a second side 176b of the membrane 176. A power source 188 electrically connects the anode assembly 180 and the cathode assembly 184. As will be appreciated, the purified water 177 may be supplied to either or both of the first chamber 172 and the second chamber 174 depending on the hydrogen production system 142. In this regard, the purified water inlet 178 may similarly be provided in either or both of the first chamber 172 and the second chamber 174. In any case, the first chamber 172 is provided with an oxygen outlet 190 for passing oxygen 192 therethrough, and the second chamber 174 is provided with a hydrogen outlet 194 for passing hydrogen 196 therethrough. In one or more embodiments, the electricity is supplied to the power source 188 from the wind turbine 51 (see FIG. 4), while in other embodiments, the electricity may be supplied to the power source 188 from another source, such as a generator disposed on the ocean platform 120, etc.

[0033] Referring to FIGS. 7 and 8, the ocean platform 120 also includes a nitrogen production system 146. Without being limited to a particular nitrogen production system, one embodiment of the nitrogen production system 146 is shown in FIG. 7 as a pressure swing adsorption (PSA) nitrogen production system, and another embodiment of the nitrogen production system 146 is shown in FIG. 8 as a membrane nitrogen production system. The nitrogen production system 146 may also utilize cryogenic distillation as is known in the art.

[0034] The nitrogen production system 146 includes at least one nitrogen production pressure vessel 200. In some embodiments, as illustrated in FIGS. 7A and 7B, the nitrogen production system 146 includes two or more pressure vessels, such as a first pressure vessel 200 and a second pressure vessel 202, etc. Regardless of the number of pressure vessels, each pressure vessel 200, 202 of the nitrogen production system 146 includes an absorption assembly 204 arranged to absorb oxygen O2 from the pressurized air stream 205 delivered to the pressure vessel 200 by the air compressor 206. The absorption assembly 204 may be formed of any material utilized to absorb or remove oxygen from the air stream 205 and may include an absorbent bed or absorbent membrane as known in the art. For example, the absorption assembly may be a carbonaceous absorbent bed having a carbon molecular sieve. The first pressure vessel 200 includes at least a first port 208 through which the pressurized air stream 205 flows into the first pressure vessel 200. The first pressure vessel 200 includes at least a second port 210 through which the nitrogen stream 212 flows out of the first pressure vessel 200. Similarly, the second pressure vessel 202 includes at least a first port 214 through which the pressurized air stream 205 flows into the second pressure vessel 202. The second pressure vessel 202 includes at least a second port 216 through which the nitrogen stream 212 flows out of the second pressure vessel 202. As known in the art, various pipes, valves, and additional ports may be utilized. It will be understood that when the flow into the pressure vessels 200, 202 is reversed, the respective first ports 208, 214 may be utilized to flush the absorption assembly 204 using a flushing fluid, such as a portion of the nitrogen stream 212, injected into the pressure vessels 200, 202 using their respective second ports 210, 216. FIG. 7A illustrates the first pressure vessel 200 generating the nitrogen stream 212 while the second pressure vessel 202 is being flushed using a portion of the nitrogen stream 212, while FIG. 7B illustrates the second pressure vessel 202 generating the nitrogen stream 212 while the first pressure vessel 200 is being flushed using a portion of the nitrogen stream 212. In one or more embodiments, the nitrogen stream 212 may then be directed to an additional nitrogen purification system 220 as known in the art.

[0035] In one or more embodiments, the marine platform 120 may include a process air intake 131 (see FIG. 4) in fluid communication with an air compressor 206. In some embodiments, the process air intake 131 is spaced apart from the platform deck 121 above the platform deck 121 to take in drier and warmer air for use by the nitrogen production system 146, while in other embodiments, the process air intake 131 is located below the platform deck 121 above the sea surface 125 to take in cooler air when a higher concentration of air input for use in the nitrogen production system 146 is desired.

[0036] Referring to FIG. 8, in other embodiments, the nitrogen production system 146 may include a nitrogen production reaction vessel 230, which is composed of an elongated cylinder 232 formed along a main axis 233. The elongated cylinder 232 has a first end 234 and a second end 236, and a cylinder wall 238 extends between the first end 234 and the second end 236. The elongated cylinder 232 is closed by a first end wall 232a closing the first end 234 of the elongated cylinder 232 and a second end wall 232b closing the second end 236 of the elongated cylinder 232.

[0037] The nitrogen production reaction vessel 230 has a nitrogen gas outlet 240 at the second end 236 of the cylinder 232, a compressed air inlet 242 at the first end 234 of the cylinder 232 and in fluid communication with at least one air compressor 206 (see FIG. 7A), and a by-product outlet 244. In one or more embodiments, the nitrogen gas outlet 240 is disposed on the second end wall 232b, the compressed air inlet 242 is disposed on the first end wall 232a, and the by-product outlet 244 is disposed on the cylinder wall 238.

[0038] A polymer fiber membrane 246 is disposed between a compressed air inlet 242 and a by-product outlet 244 within the reaction vessel 230. In one or more embodiments, the cylindrical wall 238 defines an interior 248 of the elongate cylinder 232, the compressed air inlet 242 is axially disposed at a first end 234 of the cylinder 232, the nitrogen gas outlet 240 is axially disposed at a second end 236 of the cylinder 232, and the by-product outlet 244 is disposed radially outward from the main axis 233 in the cylindrical wall 238. In the illustrated embodiment of FIG. 8, the compressed air stream 205 is introduced into the interior 248 of the cylinder 232. Under pressure, oxygen is moved radially outward and flows through the membrane 246 to the outlet 244, while the nitrogen stream 212 continues to flow longitudinally along the cylinder 232 to the nitrogen gas outlet 240. In one or more embodiments, the polymer fiber membrane 246 is configured as a plurality of axially extending elongate tubes 250 that are parallel to the main axis 233 and disposed within the interior 248 of the elongate cylinder 232. In one or more embodiments, the polymer fiber membrane 246 is disposed around the inner surface of the cylindrical wall 238, while in other embodiments, the polymer fiber membrane 246 forms a column or floor between the first end 234 and the second end 236 of the elongate cylinder 232.

[0039] Although it will be understood that the present disclosure is not limited to a particular ammonia production system 136, FIG. 9 illustrates one embodiment of an ammonia production system 136. Nitrogen gas from the nitrogen production system 146 and hydrogen gas from the hydrogen production system 142 are pressurized by one or more compressors 260 having a supply gas inlet 260a and a compressed supply gas outlet 260b. In one or more embodiments, nitrogen gas and hydrogen gas are mixed and supplied together to the supply gas inlet 260a of the compressor 260, and the compressor 260 compresses the mixed gas into a supply gas stream 262 of hydrogen and nitrogen. The supply gas stream 262 exiting from the supply gas outlet 260b is then directed to a preheater 264, where the supply gas stream 262 is preheated. Specifically, the preheater inlet 264a is in fluid communication with the supply gas outlet 260b of the compressor 260. After the heated pressurized supply gas stream 262 exits the preheater 264 via the supply gas outlet 264b, the heated pressurized supply gas stream 262 is contacted with a catalyst assembly 266 disposed within the ammonia production reactor 268. In some embodiments, the reactor 268 may be a column formed of a long vertical vessel 270 in which the catalyst assembly 266 is disposed. In one or more embodiments, the catalyst assembly 266 may be an iron or iron-based catalyst supported on a catalyst bed as known in the art. In one or more embodiments, the preheater 264 may be integrally disposed inside the reactor 268. In any case, the reactor 268 includes an inlet 274 in fluid communication with the outlet 264b of the preheater 264. In one or more embodiments, the pressure and temperature of the supply gas stream 262 introduced into the reactor 268 are at least about 400-450 degrees Celsius at about 200 atmospheres. The reactor 268 also includes an ammonia gas outlet 272 through which a hot ammonia gas stream 273 exits the reactor 268. In one or more embodiments where the reactor 268 is a long vertical vessel 270, the inlet 274 is disposed below the catalyst assembly 266 at the lower portion 270a of the long vertical vessel 270, and the outlet 272 is disposed above the catalyst assembly 266 at the upper portion 270b of the long vertical vessel 270.

[0040] The outlet 272 of the reactor 268 is in fluid communication with a liquefaction system 280 that includes at least a condenser 282 for producing liquefied ammonia from the ammonia gas stream 273. In some embodiments, the liquefaction system 280 may also include a heat exchanger assembly 284 having an ammonia gas inlet 284a and an ammonia gas outlet 284b that processes the high-temperature ammonia gas stream 273 prior to introduction into the condenser 282. In one embodiment, the condenser 282 may have a heat exchange mechanism 286 disposed within a condensation vessel 288. The ammonia gas inlet 290 of the condenser 282 is in fluid communication with the outlet 272 of the vessel 270. By the cooling fluid inlet 292 and the cooling fluid outlet 294 of the condenser 282, the cooling fluid 296 can pass through the condenser 282 to condense the ammonia gas introduced into the condenser 282. In one or more embodiments, the cooling fluid 296 is seawater and the cooling fluid inlet 292 is in fluid communication with a seawater intake 129 (see FIG. 4), while in other embodiments, the cooling fluid inlet 292 may be in fluid communication with purified water from the water purification unit 140. Finally, the condenser 282 includes a liquefied ammonia outlet 298 for removing the ammonia condensed from the condenser 282. In some embodiments, the cooling fluid passes through the heat exchanger assembly 284, while in other embodiments, the high-temperature ammonia gas stream passes through the heat exchanger assembly 284. In any case, the liquefied ammonia from the liquefied ammonia outlet 298 may then be recovered into a cryogenic storage tank such as 128 of the floating liquefied ammonia storage unit 126 shown in FIG. 4, for example. In one or more embodiments, as shown in FIG. 9 for example, the heat exchanger assembly 284 may be utilized to cool the high-temperature ammonia gas stream 273 prior to introduction into the condenser 282. In such a case, using the inlet 287a and the outlet 287b, a cooling fluid such as seawater or purified water from the water purification unit 140 may be introduced into the heat exchanger assembly 284 and circulated therein.In other embodiments, the heat exchanger assembly 284 may utilize the high temperature ammonia gas stream 273 from the reactor 268 to heat the unreacted nitrogen and hydrogen gases recovered from the ammonia gas stream 273 introduced into the condenser 282. In such a case, the unreacted nitrogen and hydrogen gases recovered from the condenser 282 circulate through the heat exchanger assembly 284 using the inlet 287a and the outlet 287b.

[0041] FIG. 10 illustrates another embodiment of an ammonia production system 136 that takes advantage of the offshore location of the offshore platform 120. Specifically, the ammonia production system 136 is shown as a reverse fuel cell assembly 300 that utilizes electricity supplied from an offshore power source 302, such as a wind turbine 51 or a solar cell assembly 304, located near the offshore platform 120, for example. Seawater is purified using a water purification unit 140 as described above, and air is processed within a nitrogen production system 146 as described above to produce nitrogen gas. The reverse fuel cell assembly 300 includes an ammonia production vessel 310 having a first chamber 312 and a second chamber 314, with a membrane 316 disposed therebetween. Without being limited to a particular type of membrane, in one or more embodiments, the membrane 316 is an ion exchange membrane. However, other membranes may also be utilized. In any case, the purified water 177 obtained from the water purification unit 140 is delivered to the ammonia production vessel 310 via a purified water inlet 318 provided in the ammonia production vessel 310. A cathode assembly 320 having a cathode 322 extending into the first chamber 312 is provided on a first side 316a of the membrane 316, and an anode assembly 326 having an anode 328 extending into the second chamber 314 is provided on a second side 316b of the membrane 316. A power source 330 electrically connects the anode assembly 326 and the cathode assembly 320. As will be appreciated, the purified water 177 is supplied to the first chamber 312 and the second chamber 314. The reverse fuel cell assembly 300 also includes a nitrogen gas inlet 334 that is in fluid communication with the nitrogen production system 146 and is arranged to introduce nitrogen gas into the purified water 177 disposed within the first chamber 312.

[0042] In some embodiments, the first chamber 312 may include a first catalyst 319, and the second chamber 314 may include a second catalyst 321. In some embodiments, the first catalyst 319 and the second catalyst 321 are suspended within their respective chambers 312, 314. In some embodiments, the first catalyst 319 covers the surface of the cathode 322, and the second catalyst 321 covers the surface of the anode 328. At the anode 328, water molecules are decomposed into oxygen, hydrogen ions, and electrons. Protons flow through the water and the membrane 316 to the cathode 322. At the cathode 322, nitrogen is decomposed into molecules, and hydrogen ions and electrons react with the nitrogen to produce ammonia.

[0043] The first chamber 312 is provided with an ammonia gas outlet 336 for passing ammonia 338, and the second chamber 314 is provided with an oxygen outlet 340 for passing oxygen 342. In one or more embodiments, electricity is supplied from a wind turbine 51 (see FIG. 4) or a solar cell assembly 304 mounted on the offshore platform 120 to the power source 188, while in other embodiments, electricity may be supplied from another source, such as a generator mounted and disposed on the offshore platform 120, to the power source 330.

[0044] The ammonia gas exiting the outlet 336 may be pumped to a liquefaction system 346 to produce liquefied ammonia for local storage, such as a floating liquefied ammonia storage unit 126.

[0045] FIG. 11 illustrates another embodiment of an ammonia production system 136 that takes advantage of the offshore location of the ocean platform 120. Specifically, the ammonia production system 136 is shown as a membrane reactor 350 that extends along an axis 353 and has a long first cylinder 352 concentrically disposed within a long second cylinder 354 that also extends along the axis 353. The first cylinder 352 is spaced from the second cylinder 354 to form an annulus 356 therebetween. The first cylinder 352 has a first end 352a and a second end 352b, and a cylinder wall 358 extends between the two ends 352a, 352b. The cylinder wall 358 has an inner surface 358a and an outer surface 358b, and a plurality of perforations 360 are formed in the cylinder wall 258. Similarly, the second cylinder 354 is formed of a cylinder wall 362 having an inner surface 362a and an outer surface 362b. A first catalyst 364 is disposed adjacent to the outer surface 358b of the first cylinder 352 to dissociate hydrogen gas molecules into hydrogen atoms for reaction with nitrogen. In some embodiments, the first catalyst 364 may also be disposed adjacent to the inner surface 362a of the outer cylinder 354 to facilitate the dissociation of hydrogen. In any case, hydrogen gas is injected into the annulus 356 under pressure. The two cylinders are exposed to heat from a heat source 365 to promote the dissociation of hydrogen into individual hydrogen atoms. In any case, under pressure, the hydrogen atoms pass through the first catalyst 364 and the perforations 360 formed in the inner cylinder 352 and enter the interior 366 of the first cylinder 352.

[0046] The second catalyst 368 is disposed adjacent to the inner surface 358a of the first cylinder 352. Nitrogen gas is injected into the inside 366 of the first cylinder 352, where dissociation of nitrogen occurs by the second catalyst 368 and the heat from the heat source 365, and ammonia is generated by hydrogen atoms passing through to the inside 366 and combining with nitrogen atoms. In one or more embodiments, the second catalyst 368 may be palladium. In one or more embodiments, a single first cylinder 352 may be replaced by a plurality of smaller first cylinders 352 each having the perforations 360, the first catalyst 364, and the second catalyst 368 as described above (similar to the configuration of the elongated tube 250 extending in the axial direction described above), in which case hydrogen is introduced axially into the plurality of first cylinders 352.

[0047] It will be understood that each of the first and second cylinders 352, 354 may be closed by end walls as depicted, for example, as 332a, 332b in FIG. 8. Similarly, the hydrogen inlet 370 may be utilized to introduce pressurized hydrogen gas into the annulus 356, and an inlet similar to the air inlet 242 of FIG. 8 may be used to introduce nitrogen into the inside 366 of one or more of the first cylinders 352. The ammonia outlet 372 may be utilized to remove ammonia gas, unreacted nitrogen, and hydrogen from the inside 366 of one or more of the first cylinders 352. The ammonia outlet 372 may be axially disposed. In this regard, similar to FIG. 8, the nitrogen inlet and the ammonia outlet 372 may be axially arranged on the opposing ends 352a, 352b of the elongated first cylinder 352 to allow for a continuous flow introducing nitrogen gas near the first end 352a and discharging ammonia gas near the second end 352b.

[0048] Referring to FIG. 12, there is shown a hydrogen fuel production system 400 in which an offshore platform 420 is located offshore to receive liquefied methane from a liquefied methane storage unit 426 located on or adjacent to the offshore platform 420. In one or more embodiments, the liquefied methane storage unit 426 is a floating storage unit moored adjacent to the offshore platform 420 and arranged to transfer liquefied methane to the offshore platform 420 for processing into hydrogen gas fuel. The floating liquefied methane storage unit 426 may include a plurality of large-capacity storage tanks 428 for receiving liquefied ammonia delivered from a liquefied methane carrier 430. In some embodiments, the total storage capacity of the liquefied methane load of the liquefied methane carrier 430 is such that the liquefied methane storage unit 426 can be utilized as a recovery or collection location for storing a small amount of liquefied methane delivered by the liquefied methane carrier 430 in large volumes. Thus, it will be understood that the total storage capacity of the liquefied methane of the floating liquefied methane storage unit 426 is greater than the total storage capacity of the liquefied methane of the liquefied methane carrier 430. That is, the floating liquefied methane storage unit 426 has a first total liquefied methane storage capacity, and the liquefied methane carrier 430 has a second total liquefied methane storage capacity that is less than the first total liquefied methane storage capacity.

[0049] In one or more embodiments, the marine platform 420 may be a jack-up platform, semi-submersible platform, barge, floating ship, fixed platform, cylindrical platform, or tension moored platform that is fixed to the ocean floor or moored in only one location during a long deployment period. In other embodiments, the marine platform 420 may be a floating ship such as a barge or a ship that can be moored in a predetermined position, for example, during a long deployment period. In other embodiments, the marine platform 420 may be a floating ship such as a barge or a ship. Further, although the marine platform 420 and the floating liquefied methane storage unit 426 are shown separately, the marine platform 420 and the floating liquefied methane storage unit 426 may be integrally formed on either the marine platform 420 or the floating liquefied methane storage unit 426. In any case, the marine platform 420 and the floating liquefied methane storage unit 426 may be relocatable to supply hydrogen corresponding to demand to consumers through intake of methane, for example, from the liquefied methane carrier 430 or the floating liquefied methane storage unit 426.

[0050] Arranged on the marine platform 420 is a hydrogen production system 436 that produces hydrogen (H2) from methane gas. The hydrogen production system 436 may also include a pretreatment unit 438 for converting liquefied methane into methane gas. In one or more embodiments, the pretreatment unit 438 may be an expansion valve, and when cryogenic methane passes through the expansion valve, the cryogenic methane is converted into methane gas. In one or more other embodiments, the pretreatment unit 438 may be a heat exchanger 439 for heating the liquefied methane from the floating liquefied methane storage unit 426, i.e., cryogenic methane. The heated liquefied methane is converted into methane gas, and then the methane gas is introduced into the reactor 441 of the hydrogen production system 436, and the reactor 441 produces a production gas mixture of hydrogen and other gases from the methane gas. Although not essential, in some embodiments, the production gas mixture may be introduced into a hydrogen purification unit 442, for example, as described above, to produce purified hydrogen from the production gas mixture.

[0051] At this point, the hydrogen produced may be used to generate electricity on the offshore platform 420, whether it is purified hydrogen or a production gas mixture. Specifically, the hydrogen produced is being used to generate electricity on the offshore platform 420. For this reason, the offshore platform 420 is provided with one or more combustion turbines 448 that generate mechanical power to be converted into electrical power by one or more generators 450. The nitrogen obtained from the hydrogen purification unit 442 may be released into the atmosphere. Additionally, in one or more embodiments, the heat generated from the combustion turbine 448 may be utilized by the hydrogen production system 436 as a heat source for the heat exchanger 439 and / or the reactor 441, or for other heating applications. Similarly, the electricity generated from the generator 450 may be utilized by the hydrogen production system 436 to operate the hydrogen production system 436. Alternatively, or in addition, the offshore platform 420 and the hydrogen production system 436 may be supplied with electricity by the offshore wind turbine 51 disposed in the vicinity of the offshore platform 420. In some embodiments, the offshore wind turbine 51 may first be used to supply electricity to the hydrogen production system 436 until the combustion turbine 448 is operated to generate mechanical power to be converted into electrical power by one or more generators 450, and then the generator 450 may supply electricity for the hydrogen production system 436. In other words, the wind turbine 51 can be used for the startup of the hydrogen production system 436, while the generator 450 can be used for ongoing operations. In any case, the electricity generated by the generator 450 can be transmitted via the transfer system 44, such as the illustrated electrical cable 44, to an onshore or coastal location or terminal.

[0052] The hydrogen production system 436 is any system utilized to produce hydrogen from methane, and may be any system including, but not limited to, catalytic cracking, thermal cracking, and methane reforming. However, FIG. 13 illustrates in more detail an embodiment of the hydrogen production system 436 by means of a flow diagram. In FIG. 13, for example, a cryopump 554 is utilized to pump liquefied methane along a flow line 557 from a cryogenic storage tank 528 that may be mounted on a liquefied methane storage unit 526 to a production reactor 540. In one or more embodiments, the pretreatment unit 538 may be disposed along the flow line 557. In the illustrated embodiment of FIG. 13, the pretreatment unit 538 is shown as a heat exchanger 538 utilized to convert liquefied methane into methane gas. The heat exchanger 538 includes a container 555 having a liquefied methane inlet 556 and a methane gas outlet 558. Although not essential, as shown, in some embodiments, the heated production gas mixture from the production reactor 540 may be used to supply heat to the heat exchanger 538. In other embodiments, the heat exchanger 38 may be supplied with heat from another source, such as combustion gas resulting from the operation of a combustion turbine 548. Further, although the heat exchanger 538 is shown as being separated from the production reactor 540, in other embodiments, the heat exchanger 538 may be integrally configured as part of the production reactor 540. In any case, the heat exchanger 538 is not limited to a particular type of heat exchanger. In the illustrated embodiment, the container 555 includes a heat exchange mechanism 560, such as a tube or a flat plate, where the heated production gas containing the produced hydrogen, methane, and other carbon-containing gases, such as carbon monoxide and carbon dioxide, is introduced into the heat exchange mechanism 560 at an inlet 562 and discharged from the heat exchange mechanism 560 at an outlet 564.

[0053] Whether the pretreatment unit 538 is a heat exchanger, an expansion valve, or some other device, the methane gas from the pretreatment unit 538 is introduced into the production reactor 540 via the methane gas inlet 570. The production reactor 540 includes a reaction vessel 572 in which the methane gas is dissociated within the reaction chamber 573. In some embodiments, a catalyst system 574 may be disposed inside the reaction vessel 572. It will be understood that the type of the catalyst system 574 will depend on the particular hydrogen production method performed by the hydrogen production system 436. For example, in some embodiments, the catalyst system 574 may include a zeolite catalyst. In some embodiments, the catalyst system 574 may include a platinum catalyst or a nickel catalyst.

[0054] In any case, heat from the heat source 576 is applied to the reaction vessel 572 to supply heat to the reaction chamber 573. In some embodiments, the heat from the heat source 576 may be applied via a heat exchanger 578 disposed adjacent to the reaction vessel 572. In one or more embodiments, the heat source 576 may be a heating coil or a heating element disposed adjacent to the reaction vessel 572. In some embodiments, the heat source 576 may be steam, such as used in steam reforming. In some embodiments, the heat source 576 may be plasma. It will be understood that the present disclosure is not limited to the particular types of hydrogen production reactors described herein, nor to their individual components.

[0055] As is known in the art, methane gas dissociates inside the production reactor 540 to produce hydrogen gas and other gases, and the gas mixture exits the production reactor 540 via the production gas outlet 580. In one or more embodiments, the production gas mixture exiting the production reactor 540 via the production gas outlet 580 can then be introduced into the hydrogen purification unit 582 for further processing. Specifically, the hydrogen purification unit 582 may include an inlet 584 that is in fluid communication with the production gas outlet 580 of the production reactor 540. In other embodiments, as shown, the gas mixture from the production reactor 540 may first be utilized in the heat exchanger 538 to preheat the liquefied methane from the cryogenic storage tank 528 before the gas mixture is introduced into the hydrogen purification unit 582. Although the hydrogen purification unit 582 is more preferred in some embodiments, it will be understood that the present disclosure is not limited to the use of a hydrogen purification unit. Further, the present disclosure is not limited to a particular type of hydrogen purification unit. For this reason, the hydrogen purification unit 582 may include, but is not limited to, a pressure swing adsorption (PSA) system having two or more pressure vessels each containing at least a nitrogen absorbent, a membrane separation system that utilizes the flow of the gas mixture through a membrane to separate hydrogen from other gases, an electrochemical separation system, and a distillation system.

[0056] In any case, the purified hydrogen exits the hydrogen purification unit 582 through the outlet 586. In one or more embodiments, the outlet 586 is in fluid communication with one or more combustion turbines 448 mounted on the offshore platform 420, whereby the hydrogen produced can be utilized as fuel within the combustion turbine 448 to generate electricity, and this electricity is then transmitted to a remote location via the transfer system 444, where the transfer system 44 may be an electrical cable. Alternatively, the transfer system may comprise both a pipeline for transferring a first portion of the hydrogen produced on the offshore platform 420 and an electrical cable for transmitting the electricity generated on the offshore platform 420 using a second portion of the hydrogen produced on the offshore platform 420.

[0057] Referring to FIGS. 14 and 15, another embodiment of a hydrogen fuel production system 610 is shown, in which the offshore platform 620 is located offshore and comprises a methane production system 636 for the production of methane, and the methane produced is liquefied and stored in large volumes in a liquefied methane storage unit 626 adjacent to the offshore platform 620, thereby utilizing the great potential of methane as a renewable hydrogen carrier. In one or more embodiments, the liquefied methane storage unit 626 is a floating liquefied methane storage unit 626 and may comprise a plurality of large-capacity storage tanks 628 for receiving the liquefied methane produced on the offshore platform 620. In the illustrated embodiment, the liquefied methane produced on the offshore platform 620 and stored in large volumes by the floating liquefied methane storage unit 626 can be transferred to a liquefied methane tanker 630 for transportation to other locations. Accordingly, the hydrogen fuel production system 610 comprises a first pump for transferring the liquefied methane produced by pumping it from the offshore platform 620 to the floating liquefied methane storage unit 626.

[0058] In one or more embodiments, the offshore platform 620 may be a jack-up platform, a semi-submersible platform, a barge, a floating vessel, a fixed platform, a cylindrical platform, or a tension-leg platform that is fixed to the ocean floor or moored in only one location during a long deployment period. In other embodiments, the offshore platform 620 may be a floating vessel such as a barge or a ship that can be moored in a predetermined position during a long deployment period. In other embodiments, the offshore platform 620 may be a floating vessel such as a barge or a ship. Further, although the offshore platform 620 and the floating liquefied methane storage unit 626 are shown separately, the offshore platform 620 and the floating liquefied methane storage unit 626 may be integrally formed on either the offshore platform 620 or the floating liquefied methane storage unit 626. Electricity for methane production may be supplied to the offshore platform 620 by one or more offshore wind turbines 51 disposed in the vicinity of the offshore platform 620.

[0059] In one or more embodiments, the offshore platform 620 includes a deck 621 and three or more platform legs 623, each leg 623 having a first end 623a and a second end 623b. The deck 621 is disposed adjacent to the first end 623a of each platform leg 623 and is supported above the sea surface 625. The second end 623b of each platform leg 623 may be connected to the sea floor 627.

[0060] In any case, the methane production system 636 uses hydrogen (H2) procured on the offshore platform 620 and a carbon source such as carbon monoxide (CO) or carbon dioxide (CO2) to produce liquefied methane in a methanation process. It will be understood that methane produced using hydrogenation as described herein is often referred to as synthetic methane.

[0061] In one or more embodiments, the marine platform 620 includes a water purification unit 640 and a hydrogen production system 642, and the hydrogen production system 642 produces hydrogen using the purified water from the water purification unit 640.

[0062] Further located on or adjacent to the marine platform 620 is a carbon source 643 that supplies carbon gas to the marine platform 620. In one or more embodiments, the carbon source 643 may supply carbon gas in the form of carbon dioxide or carbon monoxide from a carbon source mounted on the marine platform 620, for example, as exhaust from a combustion turbine 648 utilized on the marine platform 620. In other embodiments, the carbon source 643 may be the exhaust from other industrial processes utilized on the marine platform 620, such as a boiler (not shown). As used herein, the carbon source 643 may include an industrial facility that burns fuel to generate exhaust gas containing carbon gas and a carbon recovery system utilized to remove carbon gas from the exhaust gas of the industrial facility. In other embodiments, the carbon source 643 may be a carbon recovery system that forms part of the combustion turbine 648 and is arranged to receive exhaust gas from the combustion turbine 648 on the marine platform 620. In other embodiments, the carbon source 643 may be a regasification system 645 mounted on the marine platform 620 that converts liquefied carbon dioxide delivered from an external source such as a transport ship similar to the transport ship 630 into a gas for use within the hydrogen production system 642. In yet other embodiments, the carbon source 643 may be a direct air capture (DAC) system 647 mounted on the marine platform 620 that directly captures carbon dioxide from the ambient air. Similar to seawater and the electricity from the offshore wind turbine 51 located in the vicinity of the marine platform 620, the air for the DAC system 647 is obtained or supplied on-site at or adjacent to the marine platform 620.

[0063] In any case, the produced hydrogen is utilized together with the carbon obtained from the carbon source 643 to produce methane in the methane production system 636. Although not limited to a specific water purification unit, in some embodiments, the water purification unit 640 of the methane production system 636 is the same as the water purification unit 140 shown in FIG. 6. This water purification unit 140 utilizes reverse osmosis and includes a water purification container 152 having a first chamber 154 and a second chamber 156, with a semi-permeable membrane 168 disposed between the first chamber 154 and the second chamber 156. A seawater inlet 160 is provided in the first chamber 154, and a purified water outlet 162 is provided in the second chamber 156. The water purification unit 140 also includes a pump 164 for pressurizing seawater in the first chamber 154. The pump 164 is in fluid communication with the seawater intake 629 shown in FIG. 13 for sucking in seawater for purification.

[0064] Referring back to FIG. 14, in one or more embodiments, the seawater intake 629 is disposed near the second end 623b of the platform leg 623 of the offshore platform 620 to suck in colder water from the nearby water mass. In other embodiments, the seawater intake 629 is disposed near the sea surface 625 between the first and second ends 623a, 623b of the platform leg 623 to suck in warmer water from the nearby water mass.

[0065] The semipermeable membrane 168 of FIG. 6 may be any membrane known to be used for reverse osmosis, but in one or more embodiments, the semipermeable membrane 168 may be a polyimide thin film (less than 200 nm) having a pore diameter of about 0.0001 microns, attached on top of a polysulfone porous layer (about 60 microns) on a nonwoven support sheet. The suctioned seawater is pumped to the water purification unit 140, where the water purification unit 140 is utilized to at least partially purify the pumped seawater to produce purified water, and then the hydrogen production system 642 of FIG. 14 is used to generate hydrogen gas from the purified water. In one or more embodiments, a purified water storage container 166 is fluidly disposed between the purified water outlet 162 of the water purification unit 140 and the hydrogen production system 642.

[0066] Continuing to refer to FIG. 6 while again referring to FIG. 14, in some embodiments, although not limited to a particular hydrogen production system, the hydrogen production system 642 on the ocean platform 620 utilizes electrolysis for hydrogen production. Thus, the hydrogen production system 642 of FIG. 14 may be the same as the hydrogen production system 142 shown in FIG. 6, and this hydrogen production system 142 is provided with a hydrogen production container 170 having a first chamber 172 and a second chamber 174, and a membrane 176 is disposed between the first chamber 172 and the second chamber 174. Although not limited to a particular type of membrane, in one or more embodiments, the membrane 176 is a proton exchange membrane (PEM) or an alkaline membrane. However, other membranes may also be utilized. In any case, the purified water 177 obtained from the water purification unit 140, or optionally the water purification unit 640, is delivered to the hydrogen production container 170 through a purified water inlet 178 provided in the hydrogen production container 170. An anode assembly 180 having an anode 182 extending into the first chamber 172 is provided on a first side 176a of the membrane 176, and a cathode assembly 184 having a cathode 186 extending into the second chamber 174 is provided on a second side 176b of the membrane 176. A power source 188 electrically connects the anode assembly 180 and the cathode assembly 184. As will be understood, depending on the hydrogen production system 142, the purified water 177 may be supplied to either one or both of the first chamber 172 and the second chamber 174. In this regard, the purified water inlet 178 may similarly be provided in either one or both of the first chamber 172 and the second chamber 174. In any case, the first chamber 172 is provided with an oxygen outlet 190 for passing oxygen 192, and the second chamber 174 is provided with a hydrogen outlet 194 for passing hydrogen 196. In one or more embodiments, the electricity is supplied from the wind turbine 61 to the power source 188, while in other embodiments, the electricity may be supplied from another source, such as a generator or the like mounted and disposed on the ocean platform 620, to the power source 188.

[0067] The methane production system 636 mounted on the ocean platform 620 is not limited to a specific configuration. In some embodiments, the methane production system 636 may include a methane production reactor or a methane production reaction column, and the methane production reactor or the methane production reaction column is provided with a catalyst system for interacting hydrogen gas injected from the hydrogen production system 642 with gaseous carbon gas for the production of methane gas.

[0068] More specifically, in one embodiment shown in FIG. 16, the methane production system 636 includes a methane production vessel 700 having a hydrogen gas inlet 702, a carbon dioxide inlet 704, and a methane gas outlet 706. In some embodiments, the methane production vessel 700 is an elongated vertical vessel having a first lower end 700a and a second upper end 700b, the hydrogen gas inlet 702 and the carbon dioxide inlet 704 are adjacent to the first lower end 700a, and the methane gas outlet 706 is adjacent to the second upper end 700b. A heat source 708 may be thermally connected to the vessel 700 to provide heat for the methanation reaction. In one or more embodiments, the heat source may be one or more combustion turbines 648 on the ocean platform 620. Disposed inside the vessel 700 is a catalyst system 710. In one or more embodiments, the catalyst system 710 is a metal-based catalyst suspended in a liquid placed inside the methane production vessel. In one or more embodiments, the metal-based catalyst is nickel. In any case, hydrogen and carbon dioxide react inside the vessel 700 to produce methane gas.

[0069] Thereafter, the methane gas produced on the ocean platform 620 is liquefied by a methane liquefaction system 646 mounted on the ocean platform 620. Although the present disclosure is not limited to a specific methane liquefaction system 646, it may include any methane liquefaction system known in the art. The liquefied methane from the methane liquefaction system 646, i.e., cryogenic methane, is then stored in a floating liquefied methane storage unit 626 for recovery until it is loaded onto one or more liquefied methane carriers 630.

[0070] A plurality of offshore wind turbines 51 may supply electricity to the offshore platform 620 to supply power to one or more of the carbon source 643, the hydrogen production system 642, the water purification unit 640, and the methane production system 636.

[0071] So far, a system for manufacturing fuel offshore has been described. The system may include an offshore ocean platform, at least one ammonia cracking system located on the ocean platform and arranged to produce hydrogen from ammonia, a floating liquefied ammonia storage unit moored adjacent to the ocean platform and in fluid communication with the ammonia cracking system, and a subsea transfer system extending from the offshore ocean platform. In other embodiments, the system includes an offshore ocean platform, at least one ammonia cracking reactor on the ocean platform, a dissociation vessel having a reaction chamber in which a catalyst bed is disposed, an ammonia gas inlet, a product gas outlet, a heat source arranged to supply heat to the reaction chamber, an ammonia cracking reactor, a regasification unit on the ocean platform having a liquefied ammonia inlet and an ammonia gas outlet, the ammonia gas outlet being in fluid communication with the ammonia gas inlet of the dissociation vessel, a floating liquefied ammonia storage unit moored adjacent to the ocean platform and in fluid communication with the liquefied ammonia inlet of the regasification unit, a cryopump arranged to pump liquefied ammonia from the floating liquefied ammonia storage unit to the regasification unit, one or more combustion turbines on the ocean platform arranged to combust hydrogen from the ammonia cracking reactor, one or more generators driven by the one or more combustion turbines, and a subsea transfer system extending away from the ocean platform, and the combustion turbine is a heat source for at least one ammonia cracking reactor. In other embodiments, the system may include an offshore ocean platform, at least one ammonia production system on the ocean platform, and a floating liquefied ammonia storage unit moored adjacent to the ocean platform and in fluid communication with the ammonia production system.In other embodiments, the system includes an offshore ocean platform, a first pump for transferring the produced liquefied ammonia from the ocean platform to a floating storage unit by pumping, a water purification unit on the ocean platform, the water purification unit having a purified water outlet and a seawater inlet, the seawater inlet being in fluid communication with one or more seawater inlets for sucking in seawater for purification, a hydrogen production unit on the ocean platform, the hydrogen production unit having a hydrogen gas outlet and a purified water inlet, the purified water inlet being in fluid communication with the purified water outlet of the water purification unit, a nitrogen production system on the ocean platform having a nitrogen gas outlet, an ammonia production system on the ocean platform having a hydrogen gas inlet in fluid communication with the hydrogen gas outlet of the hydrogen production unit, a nitrogen gas inlet in fluid communication with the nitrogen gas outlet of the nitrogen production unit, and an ammonia gas outlet, a liquefaction system in fluid communication with the ammonia gas outlet of the ammonia production unit and having a liquefied ammonia outlet, a plurality of offshore wind turbines arranged to supply electricity to at least one of the hydrogen production unit, the nitrogen production system, or the ammonia production system, and a floating liquefied ammonia storage unit moored adjacent to the ocean platform and in fluid communication with the liquefied ammonia outlet of the liquefaction system. In other embodiments, the system may include an offshore ocean platform, at least one methane cracking system disposed on the ocean platform, a floating liquefied methane storage unit moored adjacent to the ocean platform and in fluid communication with the methane cracking system, a pump for pumping liquefied methane from the liquefied methane storage container to the offshore ocean platform, and a hydrogen gas transfer system extending from the offshore ocean platform.In other embodiments, the system may include an offshore marine platform, at least one methane cracking reactor on the marine platform, the dissociation vessel having a reaction chamber therein, a methane gas inlet, a product gas outlet, a heat source arranged to supply heat to the reaction chamber, a methane cracking reactor; a regasification unit on the marine platform having a liquefied methane inlet and a methane gas outlet, the methane gas outlet being in fluid communication with the methane gas inlet of the dissociation vessel; a floating liquefied methane storage unit moored adjacent to the marine platform and in fluid communication with the liquefied methane inlet of the regasification unit; a cryopump arranged to pump liquefied methane from the floating liquefied methane storage unit to the regasification unit; one or more combustion turbines on the marine platform arranged to combust hydrogen from the methane cracking reactor; one or more generators driven by the one or more combustion turbines; and a subsea transfer system extending away from the marine platform, wherein the combustion turbine is a heat source for at least one methane cracking reactor. In other embodiments, the system may include an offshore marine platform, at least one methane production system on the marine platform, at least one hydrogen supply source on the marine platform in fluid communication with the methane production system, at least one carbon dioxide supply source on the marine platform in fluid communication with the methane production system, and a floating liquefied methane storage vessel moored adjacent to the marine platform and in fluid communication with the at least one methane production system.In other embodiments, the system includes an offshore ocean platform, a water purification unit on the ocean platform, the water purification unit having a purified water outlet and a seawater inlet, the seawater inlet being in fluid communication with one or more seawater inlets adjacent to the ocean platform for sucking in seawater for purification; a hydrogen production unit on the ocean platform, the hydrogen production unit having a hydrogen gas outlet and a purified water inlet, the purified water inlet being in fluid communication with the purified water outlet of the water purification unit; a carbon source disposed on the ocean platform and arranged to supply carbon gas; a methane production system on the ocean platform, the methane production system including a methane production vessel having a hydrogen gas inlet in fluid communication with the hydrogen production unit, a carbon gas inlet in fluid communication with the carbon source, and a methane gas outlet, a catalyst disposed within the methane production vessel, and a heat source thermally connected to the methane vessel; a liquefaction system in fluid communication with the methane gas outlet of the methane production system and having a liquefied methane outlet; a plurality of offshore wind turbines arranged to supply electricity to at least one of the hydrogen production unit, the carbon source, or the methane production system; and a floating liquefied methane storage unit moored adjacent to the ocean platform and in fluid communication with the liquefied methane outlet of the liquefaction system.

[0072] Any of the above-described offshore fuel production systems may further include any of the following, either alone or in combination. A hydrogen purification unit disposed on the ocean platform and in fluid communication with an ammonia cracking system.

[0073] The ammonia cracking system includes a pretreatment unit 38 for converting liquefied ammonia to ammonia gas and a catalytic cracking reactor for producing a product gas mixture of at least hydrogen and nitrogen from the ammonia gas.

[0074] The catalytic cracking reactor comprises an ammonia gas inlet, a reaction vessel having a reaction chamber, a catalyst bed comprising nickel and disposed within the reaction chamber, a heat source disposed to provide heat to the reaction chamber, and a product gas outlet.

[0075] The ammonia cracking system further includes a pretreatment unit in fluid communication with the floating liquefied ammonia storage unit. A plurality of offshore wind turbines positioned proximate to the marine platform and electrically connected to the ammonia cracking system.

[0076] The transfer system includes a gas pipeline in fluid communication with one of a hydrogen purification unit, an ammonia cracking system, or a mixing unit mounted on the offshore platform.

[0077] The transportation system includes both a gas pipeline and an electrical cable. The hydrogen purification unit is equipped with a pressure swing adsorption (PSA) system. The first pump transfers the produced liquefied ammonia from the offshore platform to the floating storage unit by pumping it.

[0078] Liquefied ammonia transport ship. The offshore platform comprises a platform deck and three or more platform legs supporting the platform deck, with at least one seawater intake disposed along at least one of the legs and in fluid communication with the water purification unit.

[0079] The offshore platform is a jack-up platform connected to the ocean floor. A number of offshore wind turbines positioned in close proximity to an ocean platform. A water purification unit on an offshore platform, comprising a water purification container having a first chamber and a second chamber, with a semi-permeable membrane disposed between the first chamber and the second chamber, a seawater inlet in the first chamber, a purified water outlet in the second chamber, and a pump for pressurizing the seawater in the first chamber. The pump is in fluid communication with one or more seawater inlets that suck in seawater for purification.

[0080] The offshore platform comprises a platform deck and three or more platform legs supporting the platform deck. At least one seawater inlet is disposed along at least one leg at a first distance from the end of the leg, and at least one seawater inlet is disposed along at least one leg at a second distance from the end of the leg, where the second distance is greater than the first distance.

[0081] A nitrogen production system on an offshore platform, the nitrogen production system having a nitrogen gas outlet. A nitrogen production system comprising a pressure swing adsorption (PSA) nitrogen production system.

[0082] A nitrogen production system comprising a membrane nitrogen production system. The nitrogen production system is a nitrogen production reaction vessel composed of a long cylinder extending along a main axis. The long cylinder has a first end and a second end, with a cylindrical wall extending between the first end and the second end. It includes a nitrogen production reaction vessel, a first end wall closing the first end of the long cylinder and a second end wall closing the second end of the long cylinder, a nitrogen gas outlet at the second end of the cylinder, a compressed air inlet at the first end of the cylinder in fluid communication with at least one air compressor, and a by-product outlet. A polymer fiber membrane is disposed between the compressed air inlet and the by-product outlet within the reaction vessel.

[0083] The cylindrical wall defines the interior of the elongated cylinder. The compressed air inlet is axially arranged at the first end of the cylinder, the nitrogen gas outlet is axially arranged at the second end of the cylinder, the by-product outlet is arranged radially outward from the main axis on the cylindrical wall, and the polymer fiber membrane is arranged around the inner surface of the cylindrical wall.

[0084] The ammonia production system includes a nitrogen inlet in fluid communication with the nitrogen gas outlet of the nitrogen production system, a hydrogen inlet in fluid communication with the hydrogen gas outlet of the hydrogen production unit, a supply gas inlet in fluid communication with the nitrogen inlet and the hydrogen inlet, and one or more compressors having a compressed supply gas outlet; a preheater inlet in fluid communication with the compressed supply gas outlet of the compressor, and a preheater having a supply gas outlet; an ammonia production reactor in fluid communication with the supply gas outlet of the preheater; a catalyst assembly disposed inside the ammonia production reactor; the ammonia production reactor including an ammonia gas outlet through which a high-temperature ammonia gas stream is sent out from the ammonia production reactor; and a liquefaction system in fluid communication with the ammonia gas outlet, the liquefaction system having a liquid ammonia outlet in fluid communication with a floating liquefied ammonia storage unit.

[0085] The liquefaction system includes a condenser for producing liquefied ammonia from the ammonia gas stream, and a heat exchanger assembly having an ammonia gas inlet in fluid communication with the ammonia gas outlet of the ammonia production reactor and an ammonia gas outlet in fluid communication with the condenser.

[0086] The catalyst assembly includes an iron-based catalyst. The ammonia production system includes an ammonia production container having a first chamber and a second chamber with a membrane disposed therebetween, a purified water inlet provided in the ammonia production container and in fluid communication with a purified water unit, a cathode assembly having a cathode extending into the first chamber on a first side of the membrane, an anode assembly having an anode extending into the second chamber on a second side of the membrane, a power source electrically connecting the anode assembly and the cathode assembly, a nitrogen gas inlet in fluid communication with a nitrogen production system and arranged to introduce nitrogen gas into purified water disposed in the first chamber, an ammonia gas outlet in the first chamber for passing ammonia, and a liquefaction system in fluid communication with the ammonia gas outlet and having a liquid ammonia outlet in fluid communication with a floating liquefied ammonia storage unit.

[0087] The power source is electrically connected to one or more of a plurality of wind turbines. The ammonia production system is a membrane reactor having a long first cylinder concentrically disposed inside a long second cylinder extending along an axis, the first cylinder being spaced from the second cylinder to form an annulus therebetween, the first cylinder defining an interior thereof, the first cylinder having a first end and a second end, a cylinder wall extending between the first end and the second end, the cylinder wall having an inner surface and an outer surface, a plurality of perforations formed in the cylinder wall, the second cylinder being composed of a cylinder wall having an inner surface and an outer surface, a first catalyst disposed adjacent to the outer surface of the first cylinder, a heat source arranged to supply heat to the first cylinder and the second cylinder, a second catalyst disposed adjacent to the inner surface of the first cylinder, a nitrogen gas inlet in fluid communication with the interior of the first cylinder, a hydrogen inlet in fluid communication with the annulus, and an ammonia gas outlet in fluid communication with the interior of the first cylinder.

[0088] The second catalyst is palladium. The first cylinder includes a plurality of first cylinders. The nitrogen inlet is at the first end of the first cylinder, and the ammonia outlet is at the second end of the first cylinder.

[0089] A hydrogen purification unit disposed on an offshore platform and in fluid communication with a methane cracking system. The methane cracking system includes a pretreatment unit for converting liquefied methane into methane gas, and a cracking reactor for producing at least a production gas mixture of hydrogen from the methane gas.

[0090] The methane cracking system includes a cracking reactor having a dissociation vessel with a reaction chamber, a methane gas inlet, a production gas outlet, and a heat source operably connected to the reactor to supply heat to the reaction chamber.

[0091] The methane cracking system is further a catalytic cracking system including the following. A floating liquefied natural gas storage unit moored adjacent to the offshore platform, a first regasification system on the offshore platform and in fluid communication with the floating liquefied natural gas storage unit, and a mixing unit on the offshore platform and in fluid communication with the first regasification system.

[0092] One or more combustion turbines arranged to burn a hydrogen-based fuel produced on the offshore platform. One or more generators driven by the combustion turbines.

[0093] The transfer system includes a gas pipeline mounted on the offshore platform and in fluid communication with one of the hydrogen purification unit, the methane cracking system, or the mixing unit.

[0094] The transfer system includes an electrical cable electrically connected to one or more generators mounted on the offshore platform. A floating liquefied natural gas storage unit moored adjacent to an offshore platform, an LNG regasification system located on the offshore platform and in fluid communication with the floating liquefied natural gas storage unit, and a mixing unit located on the offshore platform and in fluid communication with each of the LNG regasification system and the methane cracking reactor, wherein the mixing unit is also in fluid communication with one or more combustion turbines for supplying LNG mixed with hydrogen from the methane cracking reactor.

[0095] A plurality of offshore wind turbines arranged near the offshore platform and electrically connected to the methane cracking reactor. The carbon source is a carbon recovery system arranged to receive exhaust from one or more combustion turbines on the offshore platform.

[0096] A hydrogen production unit on the offshore platform, having a hydrogen production container having a first chamber and a second chamber with a membrane disposed therebetween, an anode assembly having an anode extending into the first chamber provided on a first side of the membrane, a cathode assembly having a cathode extending into the second chamber on a second side of the membrane, a power source electrically connected to the anode assembly and the cathode assembly, an oxygen outlet in the first chamber, and a hydrogen gas outlet in the second chamber, wherein the power source electrically connects the anode assembly and the cathode assembly.

[0097] One or more combustion turbines located on the offshore platform and arranged to burn hydrogen from a hydrogen source. One or more combustion turbines are thermally connected to a methane production system, and one or more combustion turbines are the carbon source.

[0098] A first pump for transferring the produced liquefied methane from the offshore platform to the floating storage unit by pumping. The carbon source is a direct air capture (DAC) system.

[0099] The carbon source is one or more combustion turbines on an offshore platform. A water purification unit on an offshore platform, comprising a water purification container having a first chamber and a second chamber with a semipermeable membrane disposed therebetween, and a pump for pressurizing seawater in the first chamber, the pump being in fluid communication with one or more seawater inlets, the seawater inlet being disposed in the first chamber, and the purified water outlet being disposed in the second chamber.

[0100] A hydrogen production unit on an offshore platform, comprising a hydrogen production container having a first chamber and a second chamber with a membrane disposed therebetween, an anode assembly having an anode extending into the first chamber provided on a first side of the membrane, a cathode assembly having a cathode extending into the second chamber on a second side of the membrane, and a power source electrically connected to the anode assembly and the cathode assembly, the purified water inlet being disposed within the hydrogen production container and the hydrogen gas outlet being within the second chamber.

[0101] One or more wind turbines disposed in the vicinity of the offshore platform, the power source being electrically connected to the one or more wind turbines. Similarly, a method for manufacturing fuel offshore has been described. The method may include mooring a liquefied ammonia storage vessel adjacent to an offshore marine platform, transferring liquefied ammonia from the liquefied ammonia storage vessel to the offshore marine platform, converting the liquefied ammonia to ammonia gas, cracking the ammonia gas on the offshore marine platform to produce hydrogen gas, and generating electricity using the hydrogen. In other embodiments, the method may include pumping seawater to a water purification system mounted on an offshore marine platform connected to the seabed, using the water purification system to at least partially purify the pumped seawater to produce purified water, pumping air to a nitrogen production system mounted on the offshore marine platform, using the nitrogen production system to produce nitrogen gas from the pumped air, generating hydrogen gas from the purified water using a hydrogen production system mounted on the offshore marine platform, and producing ammonia gas from the nitrogen gas and the hydrogen gas using an ammonia production system mounted on the offshore marine platform. In other embodiments, the method may include pumping seawater to a water purification system on the offshore marine platform, using the water purification system to at least partially purify the pumped seawater to produce purified water, generating hydrogen gas from the purified water using a hydrogen production system mounted on the offshore marine platform, producing carbon gas from a carbon source on the platform, and producing methane gas from the carbon gas and the hydrogen gas using a methane production system on the offshore marine platform.

[0102] Any of the above-described embodiments of the method may include any of the following, either alone or in combination. Transferring at least a portion of the hydrogen gas to a location remote from the marine platform using a subsea transfer system.

[0103] The utilization process includes delivering liquefied natural gas to an offshore platform, where the delivered natural gas has a first hydrogen content, gasifying the delivered natural gas to produce gaseous natural gas, and mixing the gaseous natural gas with at least a portion of the hydrogen gas produced on the offshore platform to produce a mixed fuel containing natural gas with a second hydrogen content greater than the first hydrogen content.

[0104] To generate electricity on the offshore platform, a portion of the mixed fuel is utilized in a combustion turbine. To generate electricity on the offshore platform, a portion of the gaseous natural gas having a second hydrogen concentration is burned in a combustion turbine, and the generated electricity is transmitted to a location away from the offshore platform.

[0105] Delivering liquefied natural gas to an offshore platform, where the delivered liquefied natural gas has a first hydrogen concentration, storing the delivered liquefied natural gas in a first floating storage unit adjacent to the offshore platform, pumping liquefied hydrogen from a floating liquefied hydrogen storage unit moored adjacent to the offshore platform to the offshore platform, gasifying the natural gas pumped and delivered to the offshore platform to produce gaseous natural gas having a first hydrogen concentration, mixing the gaseous natural gas having a first hydrogen concentration with at least a portion of the hydrogen gas to produce gaseous natural gas having a second hydrogen concentration, and burning a portion of the gaseous natural gas having a second hydrogen concentration in a combustion turbine to generate electricity on the offshore platform.

[0106] The utilization includes burning a portion of the hydrogen in a combustion turbine to generate electricity on the offshore platform. Transmitting the generated electricity away from the offshore platform to a power distribution system.

[0107] Operating at least one of a nitrogen production system, a hydrogen production system, and an ammonia production system using electricity from one or more offshore wind turbines. Converting ammonia gas to liquefied ammonia using a liquefaction system on an offshore platform and then pumping the liquefied ammonia to a floating liquefied ammonia storage unit moored adjacent to the offshore platform.

[0108] Collecting a sufficient amount of liquefied ammonia on the floating liquefied ammonia storage unit and then pumping the liquefied ammonia from the floating liquefied ammonia storage unit to a liquefied ammonia carrier, wherein the sufficient amount of liquefied ammonia collected on the floating storage unit is more than the total storage capacity of the liquefied ammonia carrier.

[0109] Collecting a sufficient amount of liquefied gas on the floating liquefied gas storage unit and then pumping the liquefied gas from the floating liquefied gas storage unit to a liquefied gas carrier, wherein the sufficient amount of liquefied gas collected on the floating storage unit is more than the total storage capacity of the liquefied gas carrier.

[0110] Converting methane gas to liquefied ammonia using a liquefaction system on an offshore platform. Pumping liquefied methane to a floating liquefied methane storage unit moored adjacent to the offshore platform.

[0111] Collecting a sufficient amount of liquefied methane on the floating liquefied methane storage unit and then pumping the liquefied methane from the floating liquefied methane storage unit to a liquefied methane carrier, wherein the amount of liquefied methane collected on the floating storage unit is more than the total storage capacity of the liquefied methane carrier.

[0112] Operating at least one of a methane production system, a hydrogen production system, and a carbon source using electricity from one or more offshore wind turbines. Producing carbon gas involves operating one or more combustion turbines on an offshore platform to generate exhaust gas, and recovering carbon gas from the exhaust gas of the combustion turbines.

[0113] Producing carbon gas includes operating a carbon recovery system on an offshore platform. Producing carbon gas includes directly removing carbon gas from air recovered from an adjacent offshore platform.

[0114] Operating one or more combustion turbines on an offshore platform to generate exhaust gas and heat, where the exhaust gas is used for the supply of carbon gas and the heat is used for the production of methane gas by a methane production system.

[0115] Although various embodiments have been shown and described, it should be understood that the present disclosure is not limited to such embodiments and includes all modifications and variations that would be apparent to those skilled in the art. Therefore, it should be understood that the present disclosure is not intended to be limited to the specific forms disclosed, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A system for manufacturing fuel offshore, comprising: an offshore marine platform; at least one ammonia cracking system disposed on the marine platform and configured to produce hydrogen from ammonia; a floating liquefied ammonia storage unit moored adjacent to the marine platform and in fluid communication with the ammonia cracking system; a subsea transfer system extending from the offshore marine platform and a system.

2. The system according to claim 1, further comprising: a hydrogen purification unit disposed on the marine platform and in fluid communication with the ammonia cracking system.

3. The system according to claim 1 or claim 2, wherein the ammonia cracking system comprises a pretreatment unit for converting liquefied ammonia into ammonia gas, and a catalytic cracking reactor for producing a product gas mixture containing at least hydrogen and nitrogen from the ammonia gas.

4. The system according to claim 3, wherein the catalytic cracking reactor comprises an ammonia gas inlet, a reaction vessel having a reaction chamber, a catalyst bed provided with nickel and disposed in the reaction chamber, a heat source disposed to supply heat to the reaction chamber, and a product gas outlet.

5. The system according to claim 4, wherein the ammonia cracking system further comprises a pretreatment unit in fluid communication with the floating liquefied ammonia storage unit.

6. The system according to any one of the preceding claims, further comprising: a plurality of offshore wind turbines disposed near the marine platform and electrically connected to the ammonia cracking system.

7. The system according to any one of the preceding claims, further comprising: a floating liquefied natural gas storage unit moored adjacent to the marine platform, a first regasification system disposed on the marine platform and in fluid communication with the floating liquefied natural gas storage unit, and a mixing unit disposed on the marine platform and in fluid communication with the first regasification system.

8. The system according to any one of the preceding claims, further comprising: One or more combustion turbines arranged to burn hydrogen-based fuel produced on the marine platform. **Claim 9** The system according to claim 8, further comprising: One or more generators driven by the combustion turbine. **Claim 10** The system according to any one of the preceding claims, The transfer system comprises a gas pipeline in fluid communication with one of a hydrogen purification unit, an ammonia cracking system, or a mixing unit mounted on the marine platform. **Claim 11** The system according to any one of the preceding claims, The transfer system comprises an electrical cable electrically connected to one or more generators mounted on the marine platform. **Claim 12** The system according to any one of the preceding claims, The transfer system comprises both a gas pipeline and an electrical cable. **Claim 13** The system according to claim 2 or any one of claims 3 to 12 when dependent on claim 2, The hydrogen purification unit comprises a pressure swing adsorption (PSA) system. **Claim 14** A system for producing fuel offshore, An offshore marine platform, At least one ammonia cracking reactor on the marine platform, the dissociation vessel having a reaction chamber with a catalyst bed disposed therein, an ammonia gas inlet, a product gas outlet, and a heat source arranged to supply heat to the reaction chamber. A regasification unit on the marine platform having a liquefied ammonia inlet and an ammonia gas outlet, the ammonia gas outlet being in fluid communication with the ammonia gas inlet of the dissociation vessel. A floating liquefied ammonia storage unit moored adjacent to the marine platform and in fluid communication with the liquefied ammonia inlet of the regasification unit. A cryopump arranged to pump liquefied ammonia from the floating liquefied ammonia storage unit to the regasification unit. One or more combustion turbines located on the offshore platform and arranged to combust hydrogen from the ammonia cracking reactor; One or more generators driven by the one or more combustion turbines; A subsea transfer system extending away from the offshore platform; Comprising; The combustion turbine is the heat source for the at least one ammonia cracking reactor, a system.

15. The system according to claim 14, further comprising: A floating liquefied natural gas storage unit moored adjacent to the offshore platform, an LNG regasification system located on the offshore platform and in fluid communication with the floating liquefied natural gas storage unit, and a mixing unit located on the offshore platform and in fluid communication with the LNG regasification system; Comprising; The mixing unit is in fluid communication with the one or more combustion turbines, a system.

16. The system according to claim 14 or claim 15, further comprising: A plurality of offshore wind turbines disposed in the vicinity of the offshore platform and electrically connected to the ammonia cracking system, a system.

17. A method for producing fuel offshore, comprising: Mooring a liquefied ammonia storage ship adjacent to an offshore platform; Transferring liquefied ammonia from the liquefied ammonia storage ship to the offshore platform; Converting the liquefied ammonia to ammonia gas; Cracking the ammonia gas on the offshore platform to produce hydrogen gas; Generating electricity using the hydrogen; Comprising, a method.

18. The method according to claim 17, further comprising: Using a subsea transfer system to transfer at least a portion of the hydrogen gas away from the offshore platform, a method.

19. The method according to claim 17 or claim 18, wherein The step of using comprises: Delivering liquefied natural gas to the offshore platform, the delivered natural gas having a first hydrogen content; Vaporizing the delivered natural gas to produce gaseous natural gas; producing a mixed fuel comprising natural gas having a second hydrogen content greater than the first hydrogen content by mixing the gaseous natural gas with at least a portion of the hydrogen gas produced on the offshore platform A method comprising.

20. The method according to claim 19, further comprising utilizing a portion of the mixed fuel in a combustion turbine to generate electricity on the offshore platform. A method comprising.

21. The method according to claim 19 or claim 20, further comprising burning a portion of the gaseous natural gas having a second hydrogen concentration in a combustion turbine to generate electricity on the offshore platform; transmitting the generated electricity to a location away from the offshore platform A method comprising.

22. The method according to any one of claims 17 to 21, further comprising delivering liquefied natural gas to the offshore platform, the delivered liquefied natural gas having a first hydrogen concentration; storing the delivered liquefied natural gas in a first floating storage unit adjacent to the offshore platform; pumping liquefied hydrogen from a floating liquefied hydrogen storage unit moored adjacent to the offshore platform to the offshore platform; vaporizing the delivered natural gas pumped to the offshore platform to produce gaseous natural gas having a first hydrogen concentration; mixing the gaseous natural gas having a first hydrogen concentration with at least a portion of the hydrogen gas to produce gaseous natural gas having a second hydrogen concentration; burning a portion of the gaseous natural gas having a second hydrogen concentration in a combustion turbine to generate electricity on the offshore platform A method comprising.

23. The method according to any one of claims 17 to 22, wherein the utilizing step comprises burning a portion of the hydrogen in a combustion turbine to generate electricity on the offshore platform. A method comprising.

24. The method according to claim 23, further comprising sending the generated electricity from the offshore platform to a power distribution system. A method comprising.

25. A system for producing fuel offshore, comprising an offshore platform, At least one ammonia production system on the marine platform, and A floating liquefied ammonia storage unit moored adjacent to the marine platform and in fluid communication with the ammonia production system A system comprising.

26. The system according to claim 25, further comprising A system comprising a first pump for transferring the produced liquefied ammonia by pumping it from the marine platform to the floating storage unit.

27. The system according to claim 26, further comprising A system comprising a liquefied ammonia carrier.

28. The system according to any one of claims 25 to 27, The marine platform comprises a platform deck and three or more platform legs supporting the platform deck, and at least one seawater intake is arranged along at least one leg and is in fluid communication with the water purification unit. A system.

29. The system according to claim 28, The offshore marine platform is a jack-up platform attached to the seabed. A system.

30. The system according to any one of claims 25 to 29, further comprising A system comprising a plurality of offshore wind turbines arranged in the vicinity of the marine platform.

31. The system according to any one of claims 25 to 30, further comprising A water purification unit on the marine platform, having a water purification container having a first chamber and a second chamber, with a semi-permeable membrane arranged between the first chamber and the second chamber, a seawater inlet in the first chamber, a purified water outlet in the second chamber, and a pump for pressurizing the seawater in the first chamber, the pump being in fluid communication with one or more seawater inlets for sucking in seawater for purification. A system.

32. The system according to claim 31, further comprising A hydrogen production unit on the marine platform, comprising a hydrogen production container having a first chamber and a second chamber, with a membrane disposed between the first chamber and the second chamber, an anode assembly having an anode extending into the first chamber provided on a first side of the membrane, a cathode assembly having a cathode extending into the second chamber on a second side of the membrane, a power source electrically connected to the anode assembly and the cathode assembly, an oxygen outlet in the first chamber, and a hydrogen gas outlet in the second chamber, and the power source electrically connecting the anode assembly and the cathode assembly, a system.

33. The system according to claim 32, wherein the power source is electrically connected to one or more of a plurality of wind turbines, a system.

34. The system according to claim 32 or claim 33, wherein the marine platform comprises a platform deck and three or more platform legs supporting the platform deck, at least one seawater intake is disposed at a first distance from the end of at least one leg along the at least one leg, at least one seawater intake is disposed at a second distance from the end of at least one leg along the at least one leg, and the second distance is greater than the first distance, a system.

35. The system according to any one of claims 25 to 34, further comprising a nitrogen production system on the marine platform, the nitrogen production system having a nitrogen gas outlet, a system.

36. The system according to claim 35, wherein the nitrogen production system comprises a pressure swing adsorption (PSA) nitrogen production system, a system.

37. The system according to claim 35, wherein the nitrogen production system comprises a membrane nitrogen production system, a system.

38. The system according to any one of claims 35 to 37, The nitrogen production system is a nitrogen production reaction vessel composed of a long cylinder extending along the main axis. The long cylinder has a first end and a second end, and a cylindrical wall extends between the first end and the second end. The system includes a nitrogen production reaction vessel, a first end wall closing the first end of the long cylinder and a second end wall closing the second end of the long cylinder, a nitrogen gas outlet at the second end of the cylinder, a compressed air inlet at the first end of the cylinder and in fluid communication with at least one air compressor, and a by-product outlet / exhaust port. A polymer fiber membrane is disposed in the reaction vessel between the compressed air inlet and the by-product outlet.

39. The system according to claim 38, wherein the cylindrical wall defines the interior of the long cylinder, the compressed air inlet is axially disposed at the first end of the cylinder, the nitrogen gas outlet is axially disposed at the second end of the cylinder, the by-product outlet / exhaust port is disposed radially outward from the main axis in the cylindrical wall, and the polymer fiber membrane is in the form of a plurality of axially extending long tubes parallel to the main axis and disposed inside the long cylinder.

40. The system according to claim 38, wherein the cylindrical wall defines the interior of the long cylinder, the compressed air inlet is axially disposed at the first end of the cylinder, the nitrogen gas outlet is axially disposed at the second end of the cylinder, the by-product outlet / exhaust port is disposed radially outward from the main axis in the cylindrical wall, and the polymer fiber membrane is disposed around the inner surface of the cylindrical wall.

41. The system according to any one of claims 25 to 40, The ammonia production system includes a nitrogen inlet in fluid communication with the nitrogen gas outlet of the nitrogen production system, a hydrogen inlet in fluid communication with the hydrogen gas outlet of the hydrogen production unit, a supply gas inlet in fluid communication with the nitrogen inlet and the hydrogen inlet, and one or more compressors having a compressed supply gas outlet; a preheater inlet in fluid communication with the compressed supply gas outlet of the compressor, and a preheater having a supply gas outlet; an ammonia production reactor in fluid communication with the supply gas outlet of the preheater; a catalyst assembly disposed inside the ammonia production reactor; and the ammonia production reactor including an ammonia gas outlet through which a high-temperature ammonia gas stream is sent out from the ammonia production reactor, and a liquefaction system in fluid communication with the ammonia gas outlet, the liquefaction system having a liquid ammonia outlet in fluid communication with the floating liquefied ammonia storage unit.

42. The system according to claim 41, wherein the liquefaction system includes a condenser for producing liquefied ammonia from an ammonia gas stream, and a heat exchanger assembly having an ammonia gas inlet in fluid communication with the ammonia gas outlet of the ammonia production reactor and an ammonia gas outlet in fluid communication with the condenser.

43. The system according to claim 41 or claim 42, wherein the catalyst assembly includes an iron-based catalyst.

44. The system according to any one of claims 25 to 43, The ammonia production system includes an ammonia production container having a first chamber and a second chamber, with a membrane disposed between the first chamber and the second chamber; a purified water inlet provided in the ammonia production container and in fluid communication with the purified water unit; a cathode assembly having a cathode extending into the first chamber on a first side of the membrane; an anode assembly having an anode extending into the second chamber on a second side of the membrane; a power source electrically connecting the anode assembly and the cathode assembly; a nitrogen gas inlet disposed in fluid communication with a nitrogen production system and configured to introduce nitrogen gas into the purified water disposed in the first chamber; an ammonia gas outlet in the first chamber for passing ammonia; and a liquefaction system in fluid communication with the ammonia gas outlet and having a liquid ammonia outlet in fluid communication with the floating liquefied ammonia storage unit.

45. The system according to any one of Claims 41 to 44, wherein the power source is electrically connected to one or more of a plurality of wind turbines.

46. The system according to any one of Claims 25 to 45, wherein the ammonia production system is a membrane reactor having a long first cylinder concentrically disposed inside a long second cylinder extending along an axis, the first cylinder being spaced from the second cylinder to form an annulus therebetween, the first cylinder defining an interior thereof, the first cylinder having a first end and a second end with a cylindrical wall extending therebetween, the cylindrical wall having an inner surface and an outer surface, a plurality of perforations being formed in the cylindrical wall, the second cylinder being composed of a cylindrical wall having an inner surface and an outer surface; a first catalyst disposed adjacent to the outer surface of the first cylinder; a heat source disposed to heat the first cylinder and the second cylinder; a second catalyst disposed adjacent to the inner surface of the first cylinder; a nitrogen gas inlet in fluid communication with the interior of the first cylinder; a hydrogen inlet in fluid communication with the annulus; and an ammonia gas outlet in fluid communication with the interior of the first cylinder.

47. The system according to Claim 46, wherein the second catalyst is palladium.

48. The system according to claim 46 or 47, wherein the first cylinder comprises a plurality of first cylinders, the system. **Claim 49** The system according to any one of claims 46 to 48, wherein the nitrogen inlet is at a first end of the first cylinder, and the ammonia outlet is at a second end of the first cylinder, the system. **Claim 50** A system for producing fuel offshore, comprising an offshore marine platform, a first pump for transferring the produced liquefied ammonia from the marine platform to a floating storage unit by pumping, a water purification unit on the marine platform, the water purification unit having a purified water outlet and a seawater inlet, the seawater inlet being in fluid communication with one or more seawater inlets for sucking in seawater for purification, the water purification unit, a hydrogen production unit on the marine platform, the hydrogen production unit having a hydrogen gas outlet and a purified water inlet, the purified water inlet being in fluid communication with the purified water outlet of the water purification unit, the hydrogen production unit, a nitrogen production system on the marine platform and having a nitrogen gas outlet, an ammonia production system on the marine platform, the ammonia production system having a hydrogen gas inlet in fluid communication with the hydrogen gas outlet of the hydrogen production unit, a nitrogen gas inlet in fluid communication with the nitrogen gas outlet of the nitrogen production unit, and an ammonia gas outlet, a liquefaction system in fluid communication with the ammonia gas outlet of the ammonia production unit and having a liquefied ammonia outlet, the liquefaction system, a plurality of offshore wind turbines arranged to supply electricity to at least one of the hydrogen production unit, the nitrogen production system, or the ammonia production system, and a floating liquefied ammonia storage unit moored adjacent to the marine platform and in fluid communication with the liquefied ammonia outlet of the liquefaction system The system comprising. **Claim 51** A method for producing fuel offshore, comprising pumping seawater to a water purification system mounted on an offshore marine platform connected to the seabed, using the water purification system to at least partially purify the pumped seawater to produce purified water, pumping air to a nitrogen production system mounted on an offshore marine platform; producing nitrogen gas from the pumped air using the nitrogen production system; generating hydrogen gas from the purified water using a hydrogen production system mounted on the offshore marine platform; producing ammonia gas from the nitrogen gas and the hydrogen gas using an ammonia production system mounted on the offshore marine platform A method comprising:

52. The method according to claim 51, further comprising: operating at least one of the nitrogen production system, the hydrogen production system, and the ammonia production system using electricity from one or more offshore wind turbines. A method.

53. The method according to claim 51 or claim 52, further comprising: converting the ammonia gas to liquefied ammonia using a liquefaction system on the marine platform, and then pumping the liquefied ammonia to a floating liquefied ammonia storage unit moored adjacent to the marine platform. A method.

54. The method according to claim 53, further comprising: collecting a sufficient amount of liquefied ammonia on the floating liquefied ammonia storage unit, and then pumping the liquefied ammonia from the floating liquefied ammonia storage unit to a liquefied ammonia transport ship, wherein the sufficient amount of liquefied ammonia collected on the floating storage unit is greater than the total storage capacity of the liquefied ammonia transport ship. A method.

55. A system for producing fuel offshore, comprising: an offshore marine platform; at least one methane cracking system disposed on the marine platform; a floating liquefied methane storage unit moored adjacent to the marine platform and in fluid communication with the methane cracking system; a pump for pumping liquefied methane from the liquefied methane storage container to the offshore marine platform; a hydrogen gas transfer system extending from the offshore marine platform A system comprising:

56. The system according to claim 55, further comprising: a hydrogen purification unit disposed on the marine platform and in fluid communication with the methane cracking system. A system.

57. The system according to claim 55 or claim 56, wherein the methane cracking system includes a pretreatment unit for converting liquefied methane into methane gas, and a cracking reactor for producing a production gas mixture containing at least hydrogen from the methane gas.

58. The system according to claim 57, wherein the methane cracking system includes a dissociation vessel having a reaction chamber, a methane gas inlet, a production gas outlet, and a heat source operably connected to the reactor to supply heat to the reaction chamber.

59. The system according to claim 58, wherein the methane cracking system is a catalytic cracking system further comprising a catalyst disposed within the vessel.

60. The system according to any one of claims 55 to 59, further comprising a plurality of offshore wind turbines disposed near the offshore platform and electrically connected to the methane cracking system.

61. The system according to any one of claims 55 to 60, further comprising a floating liquefied natural gas storage unit moored adjacent to the offshore platform, a first regasification system located on the offshore platform and in fluid communication with the floating liquefied natural gas storage unit, and a mixing unit located on the offshore platform and in fluid communication with the first regasification system.

62. The system according to any one of claims 55 to 61, further comprising one or more combustion turbines arranged to burn the hydrogen-based fuel produced on the offshore platform.

63. The system according to claim 62, further comprising one or more generators driven by the combustion turbine.

64. The system according to any one of claims 55 to 63, wherein the transfer system includes a gas pipeline in fluid communication with one of a hydrogen purification unit mounted on the offshore platform, the methane cracking system, or the mixing unit.

65. The system according to any one of claims 55 to 64, wherein The transfer system is a system comprising an electrical cable electrically connected to one or more generators mounted on the marine platform.

66. A system according to any one of claims 55 to 65, wherein the transfer system comprises both a gas pipeline and an electrical cable.

67. A system according to claim 56 or any one of claims 57 to 66 when dependent on claim 56, wherein the hydrogen purification unit comprises a pressure swing adsorption (PSA) system.

68. A system for producing fuel offshore, an offshore marine platform, at least one methane cracking reactor on the marine platform, the dissociation vessel having a reaction chamber therein, a methane gas inlet, a production gas outlet, and a heat source arranged to supply heat to the reaction chamber, a methane cracking reactor; a regasification unit on the marine platform having a liquefied methane inlet and a methane gas outlet, the methane gas outlet being in fluid communication with the methane gas inlet of the dissociation vessel; a floating liquefied methane storage unit moored adjacent to the marine platform and in fluid communication with the liquefied methane inlet of the regasification unit; a cryopump arranged to pump liquefied methane from the floating liquefied methane storage unit to the regasification unit; one or more combustion turbines on the marine platform arranged to combust hydrogen from the methane cracking reactor; one or more generators driven by the one or more combustion turbines; a subsea transfer system extending away from the marine platform and comprising wherein the combustion turbine is the heat source for the at least one methane cracking reactor.

69. A system according to claim 68, further comprising A floating liquefied natural gas storage unit moored adjacent to the offshore platform, an LNG regasification system on the offshore platform and in fluid communication with the floating liquefied natural gas storage unit, and a mixing unit on the offshore platform and in fluid communication with each of the LNG regasification system and the methane cracking reactor, wherein the mixing unit is also in fluid communication with the one or more combustion turbines to supply LNG mixed with hydrogen from the methane cracking reactor. **Claim 70** The system according to claim 68 or claim 69, further comprising A plurality of offshore wind turbines arranged near the offshore platform and electrically connected to the methane cracking reactor. **Claim 71** A system for producing fuel offshore, comprising An offshore platform, At least one methane production system on the offshore platform, At least one hydrogen supply source on the offshore platform and in fluid communication with the methane production system, At least one carbon dioxide supply source on the offshore platform and in fluid communication with the methane production system, A floating liquefied methane storage vessel moored adjacent to the offshore platform and in fluid communication with the at least one methane production system A system. **Claim 72** The system according to claim 71, wherein The carbon supply source is a direct air capture (DAC) system. **Claim 73** The system according to claim 71 or claim 72, wherein The carbon supply source is one or more combustion turbines on the offshore platform. **Claim 74** The system according to any one of claims 71 to 73, wherein The carbon supply source is a carbon recovery system arranged to receive exhaust from one or more combustion turbines on the offshore platform. **Claim 75** The system according to any one of claims 71 to 74, further comprising A water purification unit on the ocean platform, the water purification unit comprising: a water purification container having a first chamber and a second chamber, with a semi-permeable membrane disposed between the first chamber and the second chamber; a seawater inlet in the first chamber; a purified water outlet in the second chamber; and a pump for pressurizing the seawater in the first chamber, the pump being in fluid communication with one or more seawater inlets for sucking in seawater for purification.

76. The system according to claim 75, further comprising: A hydrogen production unit on the ocean platform, the hydrogen production unit comprising: a hydrogen production container having a first chamber and a second chamber, with a membrane disposed between the first chamber and the second chamber; an anode assembly having an anode extending into the first chamber provided on a first side of the membrane; a cathode assembly having a cathode extending into the second chamber on a second side of the membrane; a power source electrically connected to the anode assembly and the cathode assembly; an oxygen outlet in the first chamber; and a hydrogen gas outlet in the second chamber. The power source electrically connects the anode assembly and the cathode assembly.

77. The system according to claim 76, further comprising: One or more wind turbines disposed in the vicinity of the ocean platform, The power source is electrically connected to the one or more wind turbines.

78. The system according to any one of claims 75 to 77, The ocean platform comprises a platform deck and three or more platform legs supporting the platform deck, with at least one seawater inlet disposed along at least one leg at a first distance from the end of the leg, and at least one seawater inlet disposed along at least one leg at a second distance from the end of the leg, the second distance being greater than the first distance.

79. The system according to any one of claims 71 to 78, further comprising: One or more combustion turbines disposed on the ocean platform and arranged to burn hydrogen from the hydrogen supply source.

80. The system according to claim 79, The one or more combustion turbines are thermally connected to the methane production system, and the one or more combustion turbines are the carbon source, the system. **Claim 81** The system according to any one of Claims 71 to 80, further comprising: A first pump for transferring the produced liquefied methane by pumping it from the offshore platform to the floating storage unit, the system. **Claim 82** A system for producing fuel offshore, An offshore platform, A water purification unit on the offshore platform, the water purification unit having a purified water outlet and a seawater inlet, the seawater inlet being in fluid communication with one or more seawater inlets adjacent to the offshore platform for sucking in seawater for purification, the water purification unit; A hydrogen production unit on the offshore platform, the hydrogen production unit having a hydrogen gas outlet and a purified water inlet, the purified water inlet being in fluid communication with the purified water outlet of the water purification unit, the hydrogen production unit; A carbon source located on the offshore platform and arranged to supply carbon gas, A methane production system on the offshore platform, the methane production system having a hydrogen gas inlet in fluid communication with the hydrogen production unit, a carbon gas inlet in fluid communication with the carbon source, and a methane gas outlet, a methane production vessel, a catalyst disposed within the methane production vessel, and a heat source thermally connected to the methane production vessel, the methane production system; A liquefaction system in fluid communication with the methane gas outlet of the methane production system, the liquefaction system having a liquefied methane outlet, A plurality of offshore wind turbines arranged to supply electricity to at least one of the hydrogen production unit, the carbon source, or the methane production system, A floating liquefied methane storage unit moored adjacent to the offshore platform and in fluid communication with the liquefied methane outlet of the liquefaction system and comprising a system. **Claim 83** The system according to Claim 82, wherein the carbon source is a direct air capture (DAC) system, the system. **Claim 84** The system according to Claim 82 or Claim 83, wherein The carbon source is one or more combustion turbines on the offshore platform, a system.

85. The system according to any one of Claims 82 to 84, wherein the carbon source is a carbon recovery system arranged to receive exhaust from one or more combustion turbines on the offshore platform, a system.

86. The system according to any one of Claims 82 to 85, further comprising a water purification unit on the offshore platform, the water purification unit having a water purification container having a first chamber and a second chamber with a semi-permeable membrane disposed therebetween, and a pump for pressurizing the seawater in the first chamber, the pump being in fluid communication with the one or more seawater inlets, the seawater inlet being disposed in the first chamber, and the purified water outlet being disposed in the second chamber, a system.

87. The system according to Claim 86, further comprising a hydrogen production unit on the offshore platform, the hydrogen production unit having a hydrogen production container having a first chamber and a second chamber with a membrane disposed therebetween, an anode assembly having an anode extending into the first chamber provided on a first side of the membrane, a cathode assembly having a cathode extending into the second chamber on a second side of the membrane, and a power source electrically connected to the anode assembly and the cathode assembly, the purified water inlet being disposed in the hydrogen production container, and the hydrogen gas outlet being in the second chamber, a system.

88. The system according to Claim 87, further comprising one or more wind turbines disposed in the vicinity of the offshore platform, the power source being electrically connected to the one or more wind turbines, a system.

89. A method for producing fuel offshore, comprising pumping seawater to a water purification system on an offshore platform, using the water purification system to at least partially purify the pumped seawater to produce purified water, using a hydrogen production system mounted on the offshore platform to generate hydrogen gas from the purified water, producing carbon gas from a carbon source on the platform Producing methane gas from the carbon gas and hydrogen gas by using the methane production system on the offshore marine platform A method comprising this.

90. The method according to claim 89, further comprising Converting the methane gas into liquefied ammonia by using the liquefaction system on the marine platform. A method comprising this.

91. The method according to claim 90, further comprising Pumping the liquefied methane to a floating liquefied methane storage unit moored adjacent to the marine platform. A method comprising this.

92. The method according to claim 90 or claim 91, further comprising Collecting a sufficient amount of liquefied methane on the floating liquefied methane storage unit, and then pumping the liquefied methane from the floating liquefied methane storage unit to a liquefied methane carrier. The amount of liquefied methane collected on the floating storage unit is greater than the total storage capacity of the liquefied methane carrier. A method comprising this.

93. The method according to any one of claims 89 to 92, further comprising Operating at least one of the methane production system, the hydrogen production system, and the carbon source by using electricity from one or more offshore wind turbines. A method comprising this.

94. The method according to any one of claims 89 to 93, wherein Producing carbon gas comprises operating one or more combustion turbines on the marine platform to generate exhaust gas, and recovering carbon gas from the exhaust gas of the combustion turbines. A method comprising this.

95. The method according to any one of claims 89 to 94, wherein Producing carbon gas comprises operating a carbon recovery system on the marine platform. A method comprising this.

96. The method according to any one of claims 89 to 95, wherein Producing carbon gas comprises directly removing carbon gas from the air recovered from the adjacent marine platform. A method comprising this.

97. The method according to any one of claims 89 to 96, further comprising Operating one or more combustion turbines on the marine platform to generate exhaust gas and heat. The exhaust gas is used for the supply of carbon gas, and the heat is used for the production of methane gas by the methane production system. A method comprising this.

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