Abstract: A primary stream of boiled-off natural gas taken from the ullage space of a liquefied natural gas storage vessel is compressed by a compressor. A flow of liquefied natural gas taken from the storage vessel is partially and forcedly vaporised in a vaporiser 36 so as to form a secondary stream of natural gas containing unvaporised liquefied natural gas. Unvaporised liquefied natural gas is disengaged from the secondary stream in a phase separator. The secondary stream is mixed with the compressed primary stream to form a supply of natural gas fuel. The fuel supply may be formed and used on board an ocean-going LNG tanker.

Abstract: A machine for recovering power from a flow of compressed gas, for example, natural gas includes a turbo-expander having a turbo-expander wheel, and a generator having a rotor able to be driven by the turbo-expander wheel and a stator about the rotor. The turbo-expander and the generator are housed in a length of pipe. The turbo-expander wheel has an obverse side facing the generator. There is a flow passage for the flow of expanded gas that places the obverse side of the wheel in gas flow communication with an outer surface of the stator. This outer surface typically carries fins to facilitate cooling of the stator by expanded gas from the turbo-expander.

Abstract: Liquefied Natural Gas (LNG) is converted to a superheated fluid at a temperature greater than 5° C. by being passed under pressure through a train of first, second and third main heat exchange stages in series, in which the natural gas is heated by a circulating heat exchange fluid flowing in heat exchange circuits. The heat exchange fluid condenses in the first and second heat exchange stages and is partially vaporised in subsidiary heat exchangers which may be heated by sea water flowing in open cycle.

Abstract: A method and apparatus for the controlled storage of liquefied gases such as liquefied natural gas in an enclosed insulated container, in which part of the liquid is withdrawn and fed to an external refrigeration unit for subcooling and the subcooled liquid is reintroduced into the container via one or more valve-controlled headers under the control of a control system operated in response to pressure and temperature signals from within the container, wherein the level of subcooling is matched to the heat inleak into the container and most or all of the subcooled liquid is reintroduced directly into the stored liquid so as to maintain stable conditions in the stored liquid and to minimise evaporation thereof.

Abstract: A method of and apparatus for converting liquefied natural gas (LNG) to a superheated fluid through vaporisation and superheating of the LNG employs a first main heat exchanger in series with a second main heat exchanger. The first main heat exchanger is heated by a condensing first heat exchange fluid flowing in a first heat exchange circuit including a first supplementary heat exchanger for revaporising the first heat exchange fluid and the second main heat exchanger by a condensing second heat exchange fluid flowing in a second heat exchange circuit including a second heat exchanger for vaporising the second heat exchange fluid. The circuits and may share a common vessel for collecting condensate. The condensing pressure of the heat exchange fluid in the first circuit is less than condensing pressure of the heat exchange fluid in the second circuit.

Abstract: A machine for recovering power from a flow of compressed gas, for example, natural gas includes a turbo-expander having a turbo-expander wheel, and a generator having a rotor able to be driven by the turbo-expander wheel and a stator about the rotor. The turbo-expander and the generator are housed in a length of pipe. The turbo-expander wheel has an obverse side facing the generator. There is a flow passage for the flow of expanded gas that places the obverse side of the wheel in gas flow communication with an outer surface of the stator. This outer surface typically carries fins to facilitate cooling of the stator by expanded gas from the turbo-expander.

Abstract: A primary stream of boiled-off natural gas taken from the ullage space (6) of a liquefied natural gas storage vessel (2) is compressed by a compressor (12). A flow of liquefied natural gas taken from the storage vessel (2) is partially and forcedly vaporised in a vaporiser (36) so as to form a secondary stream of natural gas containing unvaporised liquefied natural gas. Unvaporised liquefied natural gas is disengaged from the secondary stream in a phase separator (42). The secondary stream is mixed with the compressed primary stream to form a supply of natural gas fuel. The fuel supply may be formed and used on board an ocean-going LNG tanker.

Abstract: A rotary liquefied natural gas boil-off compressor has a series of compression stages. A gas passage passes through the series of compression stages. The gas passage extends through and is in heat exchange relationship with cooling means in the form of indirect heat exchangers. Each of the heat exchangers is cooled by LNG supplied from a pipeline. Flow control valves are provided for controlling the flow of LNG to the heat exchangers respectively. The valves are controlled in response to temperature sensors respectively, so as to maintain the inlet temperature of each of the compression stages at a chosen sub-ambient temperature or between chosen sub-ambient temperature limits.

Abstract: A method and apparatus for the controlled storage of liquefied gases such as liquefied natural gas in an enclosed insulated container, in which part of the liquid is withdrawn and fed to an external refrigeration unit for subcooling and the subcooled liquid is reintroduced into the container via one or more valve-controlled headers under the control of a control system operated in response to pressure and temperature signals from within the container, wherein the level of subcooling is matched to the heat inleak into the container and most or all of the subcooled liquid is reintroduced directly into the stored liquid so as to maintain stable conditions in the stored liquid and to minimise evaporation thereof.

Abstract: An apparatus for use on board ship to reliquefy a compressed vapour employs pre-assemblies of components. The reliquefaction is effected in a closed cycle in which a working fluid is compressed in at least one compressor, is cooled in a first heat exchanger, is expanded in a turbine and is warmed in a second heat exchanger in which the compressed vapour is at least partially condensed. The apparatus comprises a first pre-assembly including the second heat exchanger and a second pre-assembly including the first heat exchanger, the compressor and the expansion turbine are positioned. The pre-assemblies are positioned on respective platforms.

Abstract: Liquefied natural gas is stored in an insulated tank, typically forming part of an ocean going tanker. Boiled off vapour is compressed in a compressor and at least partially condensed in a condenser. The resulting condensate is returned to the tank. The vapour is mixed with liquefied natural gas in a mixing chamber upstream of the compressor. The liquefied natural gas so mixed with the vapour in the mixing chamber is taken from the condensate or from the storage tank.

Abstract: A cryogenic turbo-expander has a rotary shaft which carries a turbine wheel and carries or is operatively associated with an energy dissipating device and which extends axially through a sleeve. Two sets of bearings, which are housed by two races surrounding the shaft, are axially spaced from one another. Each race has an aperture therein extending from an outer to an inner surface thereof communicating with a lubricating oil passage extending from an outer surface to an inner surface of the sleeve. Both races are arranged so that spent lubricating oil can pass therefrom to a common drain passage. The cryogenic turbo-expander additionally includes a reservoir for lubricating oil communicating with the aperture in the first race via an intermittently-operable metering pump and with the second race via an intermittently operable metering pump.

Abstract: Liquefied natural gas is stored in an insulated tank, typically forming part of an ocean going tanker. Boiled off vapor is compressed in a compressor and at least partially condensed in a condenser. The resulting condensate is returned to the tank. The vapor is mixed with liquefied natural gas in a mixing chamber upstream of the compressor. The liquefied natural gas so mixed with the vapor in the mixing chamber is taken from the condensate or from the storage tank.

Abstract: An apparatus for use on board ship to reliquefy a compressed vapor employs pre-assemblies of components. The reliquefaction is effected in a closed cycle in which a working fluid is compressed in at least one compressor, is cooled in a first heat exchanger, is expanded in a turbine and is warmed in a second heat exchanger in which the compressed vapor is at least partially condensed. The apparatus comprises a first pre-assembly including the second heat exchanger and a second pre-assembly including the first heat exchanger, the compressor and the expansion turbine are positioned. The pre-assemblies are positioned on respective platforms.

Abstract: A cryogenic rotary pump for pressurizing a flow of a cryogenic liquid and for dividing the flow into a first lower pressure and a second higher pressure stream has a series of pumping chambers. A single rotary drive shaft carries a rotary inducer located in the chamber, a first impeller in the chamber, and a second impeller in the chamber. A liquid receiving chamber is located intermediate the pumping chambers. A first outlet from the pump for the first lower pressure stream is contiguous to the chamber and a second outlet is provided for the second higher pressure stream. The pump may serve to pressurize a flow of unboiled liquid oxygen from a sump of a lower pressure column of a double column also having a higher pressure column.