Methods and systems for liquefying natural gas using environmentally-friendly low combustibility refrigerants are provided. Methods of liquefaction include cooling a fluid in an LNG facility via indirect heat exchange with an environmentally-friendly low combustibility refrigerants that are propane, ethane and methane mixed with small amounts of fluorinated olefin, but still within close proximity to the boiling points of the pure refrigerants such that the mixed refrigerants can still be used in an optimized cascade process.

A liquefaction system and method for producing liquefied natural gas (LNG) is provided. The liquefaction system may include a heat exchanger to cool natural gas to LNG, a first compressor to compress and combine first and second portions of a single mixed refrigerant from the heat exchanger, a first cooler to cool the single mixed refrigerant from the first compressor to a first liquid phase and a gaseous phase, and a first liquid separator to separate the first liquid phase from the gaseous phase. The liquefaction system may also include a second compressor to compress the gaseous phase, a second cooler to cool the compressed gaseous phase to a second liquid phase and the second portion of the single mixed refrigerant, a second liquid separator to separate the second liquid phase from the second portion of the single mixed refrigerant, and a pump to pressurize the first liquid phase.

The present invention relates to a cryogen-gas liquefaction system (1) and method comprising: a storage container (2) comprising a liquid storage portion (3) and a neck portion (4) with a liquefaction region (8) above said bath (7); a coldhead (9) arranged at the neck portion (4) comprising one or more refrigeration stages (10, 11); a gas intake module (12) containing an amount of gas-phase cryogen for its introduction into the storage container (2); and a pressure control mechanism (13) for controlling the cryogen gas pressure within the liquefaction region (8) of the storage container (2). Advantageously, the coldhead (9) further comprises: a refrigeration compressor (17) for distributing gas-phase cryogen inside the coldhead (9); one or more extraction orifices (22) communicating a gas circulation circuit inside the coldhead (9) with the external region of the refrigeration stages (10, 11), acting as pass-through ports (23); and a gas injection source (19) connected with the gas circulation circuit of said refrigeration compressor (17) through a gas injection valve (20), that maintains a total amount of gas constant in the compressor gas circuit, to compensate for the amount of gas extracted and liquefied through the extraction orifices (22).

A method is provided for operating a system for the liquefaction of gas of the type comprising a main heat exchange vessel, a bundle for the gas to be liquefied extending through said MCHE and a refrigerant compression circuit of which a first end leads evaporated refrigerant from the vessel towards a compressor and a second end supplies the compressed and cooled refrigerant from the compressor towards the MCHE. For avoiding problems during heat up or during start up of the heat exchanger the pressure within the liquefaction system is controlled by regulating the amount of evaporated refrigerant in the liquefaction circuit.

A distillation apparatus includes a first distillation column and one or more second distillation columns. A higher-pressure part of the first distillation column includes at least part of a rectifying section, and performs gas-liquid contact at a relatively high pressure. A lower pressure-part of the first distillation column includes at least part of a stripping section and performs gas-liquid contact at a relatively low pressure. A vapor line, which includes a pressurizing means, directs a vapor discharged from a column top of the lower-pressure part to a column bottom of the higher-pressure part. A liquid line directs a liquid discharged from the column bottom of the higher-pressure part to the column top of the lower pressure part. Corresponding heat exchange structures transfer heat in both directions between the rectifying section of the first distillation column and at least one second distillation column.

The device comprises: a shell defining an interior volume to receive the first fluid extending along a longitudinal axis; a tube bundle arranged inside the shell, the tube bundle extending longitudinally in the interior volume to receive the second fluid; a disengagement member, able to perform liquid vapor separation in the fluid carried from the interior volume, the disengagement member being arranged above the tube bundle. In at least one plane perpendicular to the longitudinal axis, the disengagement member includes at least two separate fluid passage regions and at least one intermediate region preventing fluid from passing.

Apparatus, systems, and methods use cryogenic liquids such as, for example, liquefied natural gas and liquefied air or liquefied air components to store thermal energy. The cryogenic liquids may be produced using electrically powered liquefaction methods, for example, using excess electric power during periods of over-generation on the electric grid.

An oxygen liquefier system may be configured to defrost an oxygen line included therein. The system may include one or more sieve beds, a liquid oxygen reservoir, an oxygen line, a controller, a heating apparatus, and/or other components. The one or more sieve beds are configured to extract oxygen from air obtained from an ambient environment. The liquid oxygen reservoir is configured to store oxygen extracted at the one or more sieve beds that has been liquefied. The oxygen line is configured to provide fluid communication between the one or more sieve beds and the liquid oxygen reservoir. The controller is configured to detect a blockage caused by frozen liquid within the oxygen line based on a liquid oxygen production rate. The heating apparatus is configured to defrost the oxygen line to melt frozen liquid within the oxygen line responsive to the detection of the blockage.

The invention relates to a liquefied gas storage facility, in particular for liquid hydrogen, comprising a liquefied gas tank intended to contain gas in liquid form and a gaseous phase, a device for cooling the contents of the tank, the cooling device comprising at least a first refrigerator with a cycle for refrigerating a cycle gas, said first refrigerator comprising, arranged in series in a cycle circuit: a member for compressing the cycle gas, a member for cooling the cycle gas, a member for expanding the second cycle gas and a member for reheating the expanded cycle gas, the cooling device comprising a first heat transfer fluid loop comprising a first end exchanging heat with a cold end of the first refrigerator and a second end comprising a first heat exchanger located in the tank, the first heat transfer fluid loop comprising a member for circulating the heat transfer fluid, characterized in that the first heat exchanger exchanges heat directly with the inside of the tank, that is to say that the first heat exchanger exchanges heat directly with the fluid which surrounds it in the tank.

Implementations described and claimed herein provide systems and methods for processing liquefied natural gas (LNG). In one implementation, a dry feed gas is received. The dry feed gas is chilled with clean vapor from a heavies removal column to form a chilled feed gas. The chilled feed gas is partially condensed into a vapor phase and a liquid phase. The liquid phase retains freezing components. The freezing components are extracted using a reflux stream in the heavies removal column. The freezing components are removed as a condensate. The vapor phase is compressed into a clean feed gas. The clean feed gas is free of the freezing components for downstream liquefaction.