Abstract: A method and system for controlling the nitrogen concentration in an LNG product and fuel from flash gas within preferred ranges. A cooled LNG stream is separated into a nitrogen-enriched vapor stream, a fuel stream, and an LNG product stream using a plurality of phase separating devices, such as flash drum or rectifying column. A portion of the vapor stream is recycled to the rectifying column as reflux. A portion of a stream having a higher concentration of nitrogen is combined with the fuel stream to maintain the fuel stream within a desired nitrogen concentration range.

Abstract: A coil-wound heat exchanger with mixed refrigerant shell side cooling that is adapted to reduce radial temperature maldistribution by providing tube sheets at one end of a warm bundle that are each connected to tube sheets in a single circumferential zone and are in fluid flow communication with a control valve. Tube sheets at the other end of the warm bundle are each connected to tube sheets in a single radial section and in multiple circumferential zones. A temperature sensor is provided in each circumferential zone. When a temperature difference is detected, one or more of the control valves is adjusted to reduce the temperature difference.

Abstract: Described herein are methods and systems for producing liquefied natural gas (LNG) from a methane-containing synthetic gas (MCSG). An MCSG feed stream may be cooled and partially liquefied using one or more heat exchanger units. A first phase separator and a second phase separator in downstream fluid flow communication with the first phase separator may be used to separate the partially liquefied MCSG stream into a first residue gas stream and first and second feed streams, the first and second feed streams then being fed into a distillation column to produce an LNG stream and a second residue gas stream.

Abstract: Described herein are methods and systems for liquefying natural gas using an open-loop natural gas refrigeration cycle; coil wound heat exchanger units suitable for cooling one or more feed streams, such as for example one or more natural gas feed streams, via indirect heat exchange with a gaseous refrigerant; and methods and systems for removing heavy components from a natural gas prior to liquefying the natural gas using an open-loop natural gas refrigeration cycle.

Abstract: A liquefaction system is capable of sequentially or simultaneously liquefying multiple feed streams of hydrocarbons having different normal bubble points with minimal flash. The liquefying heat exchanger has separate circuits for handling multiple feed streams. The feed stream with the lowest normal boiling point is sub-cooled sufficiently to suppress most of the flash. Feed streams with relatively high normal boiling points are cooled to substantially the same temperature, then blended with bypass streams to maintain each product near its normal bubble point. The system can also liquefy one stream at a time by using a dedicated circuit or by allocating the same feed to multiple circuits.

Abstract: Integration of a natural gas liquefaction system, a hydrogen production system, and power generation system to increase CO2 capture and improve overall plant efficiency. The predominantly methane endflash is sent to the hydrogen production system which produces hydrogen and CO2. The CO2 may be captured or beneficially used. At least a portion of the hydrogen produced is used to fuel gas turbines in the power generation which, in turn, provides power for the refrigeration compressor of the natural gas liquefaction system—either in the form of mechanical work or electricity.

Abstract: A natural gas liquefaction method and system having integrated nitrogen removal. Recycled LNG gas is cooled in a separate and parallel circuit from the natural gas stream in the main heat exchanger. Cooled recycled gas and natural gas streams are directed to a nitrogen rectifier column after the warm bundle. The recycle stream is introduced to the rectifier column above the natural gas stream and at least one separation stage is located in the rectifier column between the recycle stream inlet and the natural gas inlet. The bottom stream from the rectifier column is directed to a cold bundle of the main heat exchanger where it is subcooled.

Abstract: Described herein are methods and systems for liquefying natural gas using an open-loop natural gas refrigeration cycle; coil wound heat exchanger units suitable for cooling one or more feed streams, such as for example one or more natural gas feed streams, via indirect heat exchange with a gaseous refrigerant; and methods and systems for removing heavy components from a natural gas prior to liquefying the natural gas using an open-loop natural gas refrigeration cycle.

Abstract: A coil-wound heat exchanger with mixed refrigerant shell side cooling that is adapted to reduce radial temperature maldistribution by providing tube sheets at one end of a warm bundle that are each connected to tube sheets in a single circumferential zone and are in fluid flow communication with a control valve. Tube sheets at the other end of the warm bundle are each connected to tube sheets in a single radial section and in multiple circumferential zones. A temperature sensor is provided in each circumferential zone. When a temperature difference is detected, one or more of the control valves is adjusted to reduce the temperature difference.

Abstract: A method and system for liquefying a natural gas feed stream and removing nitrogen therefrom.

Abstract: Systems and methods are described for increasing capacity and efficiency of a nitrogen refrigerant boil-off gas recovery system for a natural gas storage tank. Boil-off gas is condensed against two-phase nitrogen in a condensing heat exchanger having an inner vessel through which the boil-off gas flows and an outer vessel through which the two phase nitrogen flows. Logic controls maintain storage tank pressure and power consumption within preferred levels by adjusting the pressure of the two-phase nitrogen in the heat exchanger. Additional logic controls maintain the temperature difference between the nitrogen streams entering into and returning from the cold end of a second heat exchanger by controlling the position of an expansion valve on the return circuit.

Abstract: Described herein are methods and systems for the liquefaction of natural gas to produce a LNG product. The methods and systems use an apparatus for separating a flash gas from a liquefied natural gas (LNG) stream to produce a LNG product and recovering refrigeration from the flash gas. The apparatus includes a shell casing enclosing a heat exchange zone comprising a coil wound heat exchanger, and a separation zone. The heat exchange zone is located above and in fluid communication with the separation zone. Flash gas is separated from the LNG product in the separation zone and flows upwards from the separation zone into the heat exchange zone where refrigeration is recovered from the separated flash gas.

Abstract: 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.

Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. A flash gas separated from the liquefied natural gas is warmed and combined with the natural gas feed stream.

Abstract: 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.

Abstract: Described herein is a method of removing refrigerant from a natural gas liquefaction system in which vaporized mixed refrigerant is withdrawn from the closed-loop refrigeration circuit and introduced into a distillation column so as to be separated into an overhead vapor enriched in methane and a bottoms liquid enriched in heavier components. Overhead vapor is withdrawn from the distillation column to form a methane enriched stream that is removed from the liquefaction system, and bottoms liquid is reintroduced from the distillation column into the closed-loop refrigeration circuit. Also described are methods of altering the rate of production in a natural gas liquefaction system in which refrigerant is removed as described above, and a natural gas liquefaction systems in which such methods can be carried out.

Abstract: A method and apparatus for liquefying a natural gas feed stream and removing nitrogen therefrom to produce a nitrogen-depleted LNG product, in which a natural gas feed stream is fed into the warm end of a main heat exchanger, cooled and at least partially liquefied, withdrawn from an intermediate location of the main heat exchanger and separated to form a nitrogen-enriched natural gas vapor stream and a nitrogen-depleted natural gas liquid stream, the liquid and vapor streams being reintroduced into an intermediate location of the main heat exchanger and further cooled in parallel to form a first LNG stream and a first at least partially liquefied nitrogen-enriched natural gas stream, respectively.

Abstract: Systems and methods described for increasing capacity and efficiency of natural gas liquefaction processes having a mixed refrigerant precooling system with multiple pressure levels comprising cooling the compressed mixed refrigerant stream and separating the cooled compressed mixed refrigerant stream into a vapor and liquid portion. The liquid portion provides refrigeration duty to a first precooling heat exchanger. The vapor portion is further compressed, cooled, and condensed, and used to provide refrigeration duty to a second precooling heat exchanger. A flash gas separated from the liquefied natural gas is warmed and combined with the natural gas feed stream.

Abstract: A system and method for increasing the efficiency of natural gas liquefaction processes by using a hybrid cooling system and method. More specifically, a system and method for converting a transcritical precooling refrigeration process to a subcritical process. In one embodiment, the refrigerant is cooled to sub-critical temperature using an economizer. In another embodiment, the refrigerant is cooled to a sub-critical temperature using an auxiliary heat exchanger. Optionally, the economizer or auxiliary heat exchanger can be bypassed when ambient temperatures are sufficiently low to cool the refrigerant to a sub-critical temperature. In another embodiment, the refrigerant is isentropically expanded.

Abstract: A liquefaction system is capable of sequentially or simultaneously liquefying multiple feed streams of hydrocarbons having different normal bubble points with minimal flash. The liquefying heat exchanger has separate circuits for handling multiple feed streams. The feed stream with the lowest normal boiling point is sub-cooled sufficiently to suppress most of the flash. Feed streams with relatively high normal boiling points are cooled to substantially the same temperature, then blended with bypass streams to maintain each product near its normal bubble point. The system can also liquefy one stream at a time by using a dedicated circuit or by allocating the same feed to multiple circuits.