A cold energy recovery facility includes a liquid hydrogen tank configured to store liquid hydrogen a first circuit configured to circulate a first working medium, a second circuit configured to circulate a second working medium having a freezing point higher than the first working medium, a first turboexpander provided in the first circuit, the first turboexpander being configured to be driven by the first working medium in a gas state, a second turboexpander provided in the second circuit, the second turboexpander being configured to be driven by the second working medium in a gas state, a first heat exchanger configured to vaporize the liquid hydrogen from the liquid hydrogen tank by heat exchange with the first working medium, a second heat exchanger configured to vaporize the first working medium in a liquid state by heat exchange with the second working medium, and a third heat exchanger configured to vaporize the second working medium in a liquid state by heat exchange with a heat medium, wherein the first circuit and the first turboexpander form a part of a first thermodynamic cycle that uses the liquid hydrogen as a low-temperature heat source in the first heat exchanger, and the second circuit and the second turboexpander form a part of a second thermodynamic cycle that uses the first working medium as a low-temperature heat source in the second 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.

Embodiments relate generally to systems and methods for pre-cooling a natural gas stream to a liquefaction plant. A system may include a compressor configured to receive a first natural gas stream at a first pressure and produce a second natural gas stream at a second pressure; an exchanger, wherein the exchanger is configured to receive the second natural gas stream as the second pressure and cool the second natural gas stream to produce a cooled natural gas stream; and an expander, wherein the expander is configured to receive the cooled natural gas stream and expand the cooled natural gas stream to produce a chilled natural gas stream from the second pressure to a third pressure.

An LNG liquefaction plant system, wherein the refrigeration content of the external or internal refrigerant is used to liquefy and sub-cool a natural gas stream to produce liquefied natural gas (LNG) in a cold box or cryogenic exchanger. The refrigerant may be an external gas (N.sub.2) or an internal (CH.sub.4—BOG) refrigerant working fluid expanded and compressed in a twin compander arrangement and compressed by a refrigerant compressor, or an external single mixed refrigerant (SMR) working fluid compressed by a refrigerant compressor and expanded thru a JT valve.

An expander and motor-compressor unit is disclosed. The unit includes a casing and an electric motor arranged in the casing. A compressor is arranged in the casing and drivingly coupled to the electric motor through a central shaft. Furthermore, a turbo-expander is arranged for rotation in the casing and is drivingly coupled to the electric motor and to the compressor through the central shaft.

Liquefier arrangements configured for flexible co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) are provided. Each liquefier arrangement comprises separate and independent nitrogen recycle circuits or loops, including a warm recycle circuit and a cold recycle circuit with a means for diverting nitrogen refrigerant between the two recycle circuits or loops. The warm recycle circuit includes a booster loaded warm turbine, a warm booster compressor and warm recycle compression whereas the cold recycle circuit includes a booster loaded cold turbine, a cold booster compressor and a separate cold recycle compression.

A natural gas liquefaction system and method for effectively and efficiently removing heavy hydrocarbons and converting natural gas into liquefied natural gas. Natural gas streams entering the system may consist of varied gas compositions, pressures, and temperatures. In embodiments the system may comprise a natural gas (NG)-to-liquefied natural gas (LNG) portion and a closed-loop refrigeration portion comprising a closed-loop single mixed refrigerant system. In other embodiments the system may comprise an NG-to-LNG portion and a closed-loop refrigeration portion comprising a closed-loop gaseous nitrogen expansion refrigeration system. All embodiments utilize an integrated heat exchanger with cold-end and warm-end sections and integrated multi-stage compressor and expander configurations (e.g. compander) in order to increase overall operation flexibility and efficiency. This optimized method and system is capable of more efficiently producing a liquefied natural gas product at a desired capacity using a minimum amount of equipment and a modularized design to reduce construction costs.

A system and method for producing liquefied natural gas (LNG) from a natural gas stream. Each of a plurality of LNG trains liquefies a portion of the natural gas stream to generate a warm LNG stream in a first operating mode, and a cold LNG stream in a second operating mode. A sub-cooling unit is configured to, in the first operating mode, sub-cool the warm LNG streams to thereby generate a combined cold LNG stream. The warm LNG streams have a higher temperature than a temperature of the cold LNG streams in the second operating mode and the combined cold LNG stream. The combined cold LNG stream has, in the first operating mode, a higher flow rate than the flow rate of the cold LNG streams in the second operating mode.

Liquefier arrangements configured for co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) configured to operate in two distinct operating modes are provided.

Liquefier arrangements configured for co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) configured to operate using direct drive motor/generator arrangement for the warm and/or cold booster compressors and turbines. Alternatively, the use of a conventional generator with a bull gear in lieu of the direct drive motor/generator arrangement on the warm turbine and warm booster compressor coupling is also disclosed.

An LNG plant comprises a cold box and a refrigeration unit fluidly coupled with a plurality of heat exchanger passes in the cold box. The refrigeration unit is configured to provide a first refrigerant stream to a first heat exchanger pass of the plurality of heat exchanger passes at a first pressure, a second refrigerant stream to a second heat exchanger pass at a second pressure, and a third refrigerant stream to a third heat exchanger pass at a third pressure. The second refrigerant stream comprises a first portion of the first refrigerant stream, and the third refrigerant stream comprises a second portion of the first refrigerant stream. The second pressure and the third pressure are both below the first pressure. The cold box is configured to produce LNG from a natural gas feed stream to the cold box using a refrigeration content from the refrigeration unit.