A methane transportation system is provided. The system may include a methane source configured to dispense methane at a first location, and an underwater vehicle. The underwater vehicle may include a propulsion system configured to transport the underwater vehicle underwater from the first location to a second location and a vessel defining a storage chamber configured to receive water and the methane from the methane source. The storage chamber of the vessel may have a pressure exceeding one atmosphere and a temperature during transport from the first location to the second location sufficient to form methane clathrate in the storage chamber. The system may further include a methane receiver configured to receive the methane released from the storage chamber at the second location. Related methods are also provided.

Provided is a pressure testing method for a high-pressure tank capable of avoiding a destruction of the high-pressure tank during a pressure test. A pressure testing method includes: extracting a plurality of AE waveforms from output waveforms of an AE sensor while increasing a pressure inside the high-pressure tank; and testing the high-pressure tank based on the extracted plurality of AE waveforms. The method includes: while increasing the pressure inside the high-pressure tank, classifying the extracted AE waveforms into first waveforms and second waveforms with a classifier that is machine-learned so as to classify the plurality of AE waveforms into the first waveforms derived from a macrocrack that increases immediately before destruction of the high-pressure tank, and the second waveforms derived from a microcrack smaller than the macrocrack; and stopping pressurization of the high-pressure tank based on the number of the first waveforms.

A pressure testing method capable of determining with a higher accuracy whether a high-pressure tank is deteriorated. The pressure testing method tests the high-pressure tank that includes a liner and a fiber-reinforced resin layer covering the outer surface of the liner and that has been used while repeating charge and discharge of gas to and from the inside thereof after undergoing a pressure resistance test conducted at a pressure resistance test pressure. The method increases the internal pressure of the high-pressure tank filled with gas to a test pressure that is lower than the pressure resistance test pressure, so that a plurality of AE waveforms is extracted from output waveforms of an AE sensor that detects AE waves generated in the high-pressure tank, and determines whether the high-pressure tank is deteriorated, on the basis of the extracted AE waveforms.

A high-pressure tank includes: a liner; an epoxy resin; a fiber; and a fiber-reinforced epoxy resin layer formed on an outer side of the liner. The epoxy resin has a contact angle on polytetrafluoroethylene ((C.sub.2F.sub.4).sub.n) of 70° or less in an uncured state.

A high-pressure vessel that includes a cylinder, at least one half-shell, and a substantially rotationally symmetrical insert member. The cylinder, forming a middle region of the high-pressure vessel, is composed of a multilayer composite plastic having a first barrier layer. The at least one half-shell is formed at an axial end of the cylinder, and is composed of a multilayer composite plastic having a second barrier layer. The substantially rotationally symmetrical insert member has a foot member at an end thereof which faces an interior of the high-pressure vessel. The foot member has a diameter that is greater than a diameter of a middle region of the insert member. The foot member is configured to substantially form a hollow cone or hollow cylinder and at least a first groove or recess filled with the multilayer composite plastic of the at least one half-shell, and which is configured to extend around at least in certain portions on an inner circumference of the foot member.

Various embodiments provide an end-to-end gaseous fuel transportation solution without using physical pipelines. A virtual pipeline system and methods thereof may involve transportation of gaseous fuels including compressed natural gas (CNG), liquefied natural gas (LNG), and/or adsorbed natural gas (ANG). An exemplary pipeline system may include a gas supply station, a mother station for treating gaseous fuels from the gas supply station, a mobile transport system for receiving and transporting the gaseous fuels, and user site for unloading the gaseous fuels from the mobile transport system. The unloaded gaseous fuels can be further used or distributed.

A high-pressure tank includes a liner, a release agent layer disposed on a surface of the liner, and a reinforcing layer disposed on the release agent layer. The reinforcing layer includes a resin and a fiber. The thickness of the release agent layer is equal to or smaller than the diameter of the fiber of the reinforcing layer.

A hydrogen tank body includes a base layer formed of a synthetic resin selected from the group consisting of silicon resin, polyphenylene sulfide, polybutylene terephthalate, polyvinyl chloride, polypropylene, polyethylene, and polycarbonate, and a liner layer formed of hydrogen impermeable resin, on an inside wall surface of the base layer.

A high-pressure tank includes: a cylindrical hollow container; an outer shell that is formed of a fiber-reinforced plastic band which is wound on an outer circumference of the hollow container to cover the outer circumference; and a cap that is attached to an inner side of at least one of one axial end and the other axial end of the outer shell. The hollow container is formed of a material which has airtightness and which is able to expand and contract in an axial direction and a radial direction inside the outer shell, and a frictional portion that is used to set a frictional resistance to an inner circumferential surface of the outer shell to be greater than that in the other area is provided in an axial intermediate portion on an outer circumferential surface of the hollow container.

A storage tank for a gas is provided. The storage tank includes a liner defining an internal compartment; a boss coupled to the liner; an interlayer covering a portion of the boss and the liner, the interlayer being non-pyrolyzed and including an interconnected web and pores having a diameter greater than the diameter of a hydrogen molecule and less than or equal to about 2 nm; and an outer shell including a carbon fiber reinforced composite, the outer shell covering the interlayer, except for an interlayer end that is in contact with the boss, so that the interlayer end defines an interlayer ring that is exposed to an external environment. The storage tank is configured so that when gas diffuses through the liner to the interlayer, the interlayer channels the gas out of the exposed interlayer ring. Methods of fabricating the storage tank are also provided.