A variable speed liquid LNG expander (X1) and a variable speed two-phase LNG expander (X2) in line, downstream from X1. The rotational speed of both expanders can be controlled and changed independent from each other. The speed of expander X1 and expander X2 is determined in such way that the amount of liquid LNG downstream from the PHS compared to the feed gas supply is maximized and the amount of vapor and boil-off downstream of X2 is minimized.

Provided are mixed refrigerant systems and methods and, more particularly, to a mixed refrigerant system and methods that provides greater efficiency and reduced power consumption via control of a liquid level in a cold vapor separator device.

The invention relates to a method for adjusting a cryogenic refrigeration apparatus including a plurality of liquefiers/refrigerators arranged in parallel in order to cool a single device. The method includes a step of calculating in real time the dynamic mean value of at least one operating parameter for all the liquefiers/refrigerators. The apparatus controlling in real time the at least one valve for controlling the stream of working gas of at least one liquefier/refrigerator in accordance with the difference between the instantaneous values of the parameter relative to said dynamic converge toward said dynamic mean value.

A method for operating an air separation unit during an unexpected disturbance is provided. The method can include the steps of: determining that a process disturbance has occurred; starting-up a liquid back-up system that is configured to deliver a product gas at a desired product pressure; and introducing compressed air from an air accumulator into the air separation unit at a location that is downstream a main air compressor and upstream a cold box, wherein the compressed air is introduced in an amount that is effective for maintaining nominal operation of the air separation unit during the process disturbance and until the liquid back-up system is delivering the product gas at the desired product pressure.

A cryogenic fluid containment system is disclosed. The system can store a fluid such as hydrogen at a cryogenic temperature and pressure. As the fluid naturally warms, the fluid can be directed to a portion of a liquefaction system that is configured to perform a cooling technique on the fluid. The cooling techniques may be Joule-Thomson cooling techniques. The liquefaction system may be equipped to perform both non-Joule-Thomson cooling techniques and Joule-Thomson cooling techniques. The system is configured to direct fluid to an appropriate portion of the liquefaction system, which may be based at least in part upon a Joule-Thomson coefficient of the fluid.

An apparatus to directly detect solids formation in a fluid under known pressure and temperature conditions is disclosed. The apparatus includes a vessel having an electromagnetic resonant cavity defined by an upper portion, a lower portion and a gap defined therebetween, the gap having resonant properties sensitive to the presence of a solid phase therein. The upper portion or the lower portion may be provided with a passage extending therethrough in fluid communication with an inlet to allow ingress of a stream of fluid to the gap and thereby purge solids from the cavity subsequent to solids formation.

The apparatus also includes one or more probes, one or more sensors and a signal processor operatively connected to said sensors and said one or more probes to directly detect solids formation in the fluid within the cavity in response to detected changes in the resonant properties of the cavity.

An apparatus for reliquefaction of boil-off gas for a vessel, comprises: a compression unit for compressing the boil-off gas discharged from the storage tank; and a heat exchanger for heat-exchanging the compressed boil-off gas compressed by the compression unit with the boil-off gas discharged from the storage tank; a first expansion means for dividing the boil-off gas passing through the heat exchanger into at least two flows including a first flow and a second flow, and expanding the divided first flow; a first intercooler for cooling the second flow remaining after the division of the first flow by using the first flow expanded by the expansion means as a refrigerant; and a receiver for receiving a second flow having passed through the first intercooler, in which a downstream pressure of the compression unit is controlled by a flow discharged from the receiver.

A BOG reliquefaction system includes: a compressor; a heat exchanger cooling the BOG compressed by the compressor through heat exchange using BOG not compressed by the compressor; a pressure reducer disposed downstream of the heat exchanger and reducing a pressure of fluid cooled by the heat exchanger; and a combination of a first temperature sensor disposed upstream of a cold fluid channel of the heat exchanger and a fourth temperature sensor disposed downstream of a hot fluid channel of the heat exchanger, combination of a second temperature sensor disposed downstream of the cold fluid channel of the heat exchanger and a third temperature sensor disposed upstream of the hot fluid channel of the heat exchanger, or combination of a first pressure sensor disposed upstream of the hot fluid channel of the heat exchanger and a second pressure sensor disposed downstream of the hot fluid channel of the heat exchanger.

A method and apparatus for liquefying a feed gas stream comprising natural gas and carbon dioxide. A method includes compressing an input fluid stream to generate a first intermediary fluid stream; cooling the first intermediary fluid stream with a first heat exchanger to generate a second intermediary fluid stream, wherein a temperature of the second intermediary fluid stream is higher than a carbon dioxide-freezing temperature for the second intermediary fluid stream; expanding the second intermediary fluid stream to generate a third intermediary fluid stream, wherein the third intermediary fluid stream comprises solid carbon dioxide; separating the third intermediary fluid stream into a fourth intermediary fluid stream and an output fluid stream, wherein the output fluid stream comprises a liquefied natural gas (LNG) liquid; and utilizing the fourth intermediary fluid stream as a cooling fluid stream for the first heat exchanger.

A method for improving the efficiency of liquefied natural gas (LNG) liquefaction including receiving a gas feed stream at an LNG facility, condensing the gas feed stream into an LNG product stream, removing nitrogen from the LNG product stream via a nitrogen rejection unit coupled with the LNG facility to produce a final LNG product stream, analyzing one or more process samples taken throughout the liquefaction and nitrogen removal processes via mass spectrometry, and adjusting one or more aspects of the LNG processing system based on the analysis.