A method for producing liquefied natural gas and a stream of liquid nitrogen including step a): producing gaseous nitrogen in an air separation unit; step b): liquefying a stream of natural gas in a natural gas liquefaction unit including a main heat exchanger and a system for producing cold; step c): liquefying the nitrogen stream resulting from step a) in the main exchanger of the natural gas liquefaction unit in parallel with the liquefied natural gas in step b); wherein all the cold necessary for liquefying the stream of nitrogen and for liquefying the natural gas is supplied by the system for producing cold of the natural gas liquefaction unit.

A device for processing boil-off gas in a liquefied gas regasification system includes a fuel compressor for compressing boil-off gas at a pressured required by a fuel consumer; a high-pressure compressor installed at the rear end of the fuel compressor in series with the fuel compressor so as to compress the low-pressure boil-off gas, which has been compressed by the fuel compressor, at a pressure required by a regasified gas consumer; a low-temperature heat exchanger for cooling the high-pressure boil-off gas compressed by the high-pressure compressor; a pressure-reducing device for reducing the pressure of the high-pressure boil-off gas, which has been cooled by the low-temperature heat exchanger, to the inner pressure of a liquefied gas storage tank for storing the liquefied gas; and a liquefied gas drum for separating flash gas generated by the pressure-reducing device in the pressure-reducing process.

Described herein are methods and systems for the liquefaction of a natural gas stream using a refrigerant comprising methane or a mixture of methane and nitrogen. The methods and systems use a refrigeration circuit and cycle that employs one or more turbo-expanders to expand one or more streams of gaseous refrigerant to provide one or more streams of at least predominantly gaseous refrigerant that are used to provide refrigeration for liquefying and/or precooling the natural gas, and a J-T valve to expand down to a lower pressure a stream of liquid or two-phase refrigerant to provide a vaporizing stream of refrigerant that provides refrigeration for sub-cooling.

A system and method for producing an LNG product stream to provide fuel to generators, as an alternative to diesel, to power drilling and other equipment. Using sales gas from a natural gas/NGL plant containing less than 95% methane as a feed stream, production of LNG having 95% or more methane in quantities of 100,000 GPD or more LNG product are achievable with the system and method. The system and method preferably combine use of strategic heat exchange between the feed and a nitrogen-methane flash vapor stream and other streams within the LNG processing system without requiring heat exchange with process streams in the natural gas/NGL plant and a rectifier column that uses an internal knockback condenser and does not require a reboiler to remove heavier components from the sales gas feed.

The present invention relates to a refrigerant composition comprising neon and hydrogen. The present invention further relates to the use of the refrigerant composition in liquefying gaseous substances such as hydrogen or helium.

A system (100) for liquefying a gas comprises a liquid piston gas multistage compressor (2). It can be arranged on-board a liquefied gas carrier for recycling boil-off gas. Such system may be easily adapted or controlled for matching wide requirement ranges for variations of the liquefaction capacity. In addition, at least part of the liquid piston gas multistage compressor can be shared between the gas liquefying system and an extra gas-fed device. Such extra gas-fed device may be in particular a gas-fuelled or hybrid fuel propulsion engine of the vessel.

Described herein are methods and systems for the liquefaction of a natural gas feed stream using a refrigerant comprising methane. The methods and systems use a refrigeration circuit and cycle that employs two or more turbo-expanders to expand two or more streams of gaseous refrigerant down to different pressures to provide cold streams of at least predominantly gaseous refrigerant at different pressures that are used to provide refrigeration for precooling and liquefying the natural gas. The resulting liquefied natural gas stream is then flashed to produce an LNG product and a flash gas, the flash gas being recycled to the natural gas feed stream.

Systems and methods for reducing the pressure of a first pressurized fluid, thereby reducing the temperature of the pressurized fluid, and utilization of the reduced-pressure and temperature fluid to cool a second fluid. Such an approach can enable a reduction in the size and weight of a hydraulic system, utilize waste energy in a system, and/or minimize electrical power requirements of a system, among other benefits.

A gas liquefaction apparatus includes at least a source-gas supply line that supplies source gas; a room-temperature heat exchanger, a preliminary-cooling heat exchanger, and a liquefaction/supercooling heat exchanger that are provided in series sequentially in the source-gas supply line and that cool the source gas; a separation drum that separates the source gas containing a condensate, which has been cooled by heat exchange up to a liquefaction temperature of the source gas or below, into a gas component and a liquefied component; and a refrigerant-gas supply line that uses a gas component separated by the separation drum as refrigerant gas to supply the refrigerant gas in a direction opposite to a supply direction of the source gas, in order of the liquefaction/supercooling heat exchanger, the preliminary-cooling heat exchanger, and the room-temperature heat exchanger.

The system comprises: a main driver configured for rotating at a substantially constant rotational speed; a rotating load configured to be driven into rotation by the main driver; a controller, for controllably adjusting a load rotational speed; a variable speed transmission, arranged between the main driver and the load and comprised of a speed summing gear arrangement having a first input shaft, a second input shaft and an output shaft; an auxiliary driver, mechanically coupled to the second input shaft of the speed summing gear arrangement. The first input shaft of the speed summing gear arrangement is drivingly coupled to the main driver. The output shaft of the speed summing gear arrangement is drivingly coupled to the rotating load. The speed of the output shaft is a combination of a speed of the main driver and of a speed of the auxiliary driver.