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 system for liquefying production gas from a gas source containing a fluid having C1-C12 entrained gases includes a first phase separator for separating the C1-C12 gases from the fluid from the gas source. The first phase separator has an inlet in fluid communication with the gas source, a gas outlet and at least one alternative outlet. A first cryogenic liquefaction vessel has an inlet and an outlet. The inlet is in fluid communication with the gas outlet of the first phase separator. The first cryogenic liquefaction vessel cools the C1-C12 gases to liquefy the C3-C12 petroleum gases. A second phase separator is provided for separating the C3-C12 liquefied gases from the C1-C2 gases. The second phase separator has an inlet, a liquid outlet and a gas outlet. The inlet is in fluid communication with the outlet of the first cryogenic liquefaction vessel. At least one storage vessel is provided in fluid communication with the liquid outlet of the second phase separator for collection of the liquefied C3-C12 petroleum gases.

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.

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.

Disclosed herein is a micro-leak detection system of a reliquefaction system for ships. The micro-leak detection system includes: a reliquefaction system reliquefying boil-off gas generated from a liquefied gas stored in a storage tank in a ship by recovering cold heat from the boil-off gas in a heat exchanger, compressing the boil-off gas, and cooling the compressed boil-gas in the heat exchanger through heat exchange with refrigerant circulated along a refrigerant circulation line; a heater heating the boil-off gas to be supplied from the storage tank to the heat exchanger through heat exchange with an antifreeze liquid; and a micro-leak detection device connected to a drain port through which a remaining liquid is drained from the heater and detecting small leaks in the heater.

A method for liquefying production gas from a gas source containing a fluid having C1-C12 entrained gases includes passing the gas through a first stage of cryogenic liquefaction to cool the gas to a temperature between −50 degrees Celsius and −87 degrees Celsius to create a fluid containing a liquefied C3-C12 petroleum gas and a gaseous C1-C2 natural gas. The liquefied C3-C12 petroleum gas and gaseous C1-C2 natural gas are passed through a second phase separator to separate the liquefied C3-C12 petroleum gas from the gaseous C1-C2 natural gas. The liquefied C3-C12 petroleum gas is collected into liquefied petroleum gas storage vessels.

A method for converting excess liquid oxygen into liquid nitrogen, including introducing a gaseous nitrogen stream into a main heat exchanger, therein exchanging heat with a vaporized oxygen stream, a vapor phase nitrogen steam, and a waste liquid nitrogen stream; thereby producing a cold gaseous nitrogen stream, an oxygen vent stream, a nitrogen vent steam, and a gaseous nitrogen waste stream, introducing the cold gaseous nitrogen stream into a secondary heat exchanger, therein exchanging heat with a liquid oxygen stream; thereby producing the vaporized oxygen stream and a cold liquid nitrogen stream, introducing the cold liquid nitrogen stream into a nitrogen pressure reduction valve thereby producing a two-phase nitrogen stream, introducing the two-phase nitrogen stream into a nitrogen flash vessel thereby producing a liquid phase nitrogen stream and the vapor phase nitrogen stream, wherein the method is performed in the absence of refrigerant turbo-expanders, refrigerant expansion turbines, or refrigerant compressors.

An apparatus for converting excess liquid oxygen into liquid nitrogen, including a main heat exchanger to exchange heat between a gaseous nitrogen stream, a vaporized oxygen stream, a vapor phase nitrogen steam, and a waste liquid nitrogen stream; thereby producing a cold gaseous nitrogen stream, an oxygen vent stream, a nitrogen vent steam, and a gaseous nitrogen waste stream, a secondary heat exchanger to exchange heat between a liquid oxygen stream and the cold gaseous nitrogen stream; thereby producing the vaporized oxygen stream and a cold liquid nitrogen stream, a nitrogen pressure reduction valve to reduce the pressure of the cold liquid nitrogen stream; thereby producing a two-phase nitrogen stream, a nitrogen flash vessel to receive the two-phase nitrogen stream, and to generate a liquid phase nitrogen stream and a vapor phase nitrogen stream, wherein the apparatus does not include any refrigerant turbo-expanders, refrigerant expansion turbines, or refrigerant compressors.

A drive system for liquefied natural gas (LNG) production. A standardized machinery string consisting of a multi-shaft gas turbine with no more than three compressor bodies, where the compressor bodies are applied to one or more refrigerant compressors employed in one or more refrigerant cycles (e.g., single mixed refrigerant, propane precooled mixed refrigerant, dual mixed refrigerant). The standardized machinery strings and associated standardized refrigerators are designed for a generic range of feed gas composition and ambient temperature conditions and are installed in opportunistic liquefaction plants without substantial reengineering and modifications. The approach captures D1BM (“Design 1 Build Many) cost and schedule efficiencies by allowing for broader variability in liquefaction efficiency with location and feed gas composition.

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.