The present disclosure provides a supercritical compressed air energy storage system. The supercritical compressed air energy storage system includes a supercritical liquefaction subsystem, an evaporation and expansion subsystem, a staged cryogenic storage subsystem, a heat storage and heat exchange subsystem, and a cryogenic energy compensation subsystem, the staged cryogenic storage subsystem being used for implementing the staged storage and release of cryogenic energy, improving efficiency of recovering cryogenic energy during energy release and energy storage, and thereby improving cycle efficiency of the system. The present disclosure does not need to provide any inputs of additional cryogenic energy and heat energy input externally, and has the advantages of high cycle efficiency, low cost, independent operation, environmental friendliness, and no limitation on terrain conditions, and it is suitable for large-scale commercial applications.

A method for loading liquefied nitrogen (LIN) into a cryogenic storage tank initially containing liquid natural gas (LNG) and a vapor space above the LNG. First and second nitrogen gas streams are provided. The first nitrogen stream has a lower temperature than the second nitrogen gas stream. While the LNG is offloaded from the storage tank, the first nitrogen gas stream is injected into the vapor space. The storage tank is then purged by injecting the second nitrogen gas stream into the storage tank to thereby reduce a natural gas content of the vapor space to less than 5 mol %. After purging the storage tank, the storage tank is loaded with LIN.

A method of liquefying natural gas. The method comprises cooling a gaseous natural gas process stream with a refrigerant flowing in a path isolated from the natural gas process stream. The refrigerant may differ in composition from a composition of the natural gas process stream, and the refrigerant composition may be selected to enhance efficiency of the refrigerant path with regard to a specific composition of the natural gas process stream. The refrigeration path may be operated at pressures, temperatures and flow rates differing from those of the natural gas process stream. Other methods of liquefying natural gas are described. A natural gas liquefaction plant is also described.

A method for energy storage which integrates charging a liquid in an energy storage facility through consumption of a power from the grid with reduction pressure of natural gas through expander at the co-located city gate station and includes recovery of mechanical power of the natural gas expander and cold thermal energy of the expanded natural gas for an increase in production of liquid air per each kW of low-demand power consumed from the grid during off-peak hours.

There is provided a system and method for producing liquefied natural gas (LNG). An exemplary method includes flowing a high-pressure stream of LNG through a first series of liquid turbines. The exemplary method also includes generating electricity by reducing the pressure of the high-pressure stream of LNG to form a low-pressure stream of LNG. The exemplary method additionally includes bypassing any one the liquid turbines that has a failure while continuing to produce electricity from the first series.

A proposed method provides a highly efficient fueled power output augmentation of the liquid air energy storage (LAES) through its integration with the semi-closed CO.sub.2 bottoming cycle. It combines the production of liquid air in air liquefier during LAES charge using excessive power from the grid and an effective recovery of stored air for production of on-demand power in the fueled supercharged reciprocating internal combustion engine (ICE) and associated expanders of the power block during LAES discharge. A cold thermal energy of liquid air being re-gasified is recovered for cryogenic capturing most of CO.sub.2 emissions from the facility exhaust with following use of the captured CO.sub.2 in the semi-closed bottoming cycle, resulting in enhancement of total LAES facility discharge power output and suppressing the thermal NOx formation in the ICE.

A method for large-scale offshore LNG production from natural gas gathered from an onshore gas pipe network is described. The natural gas is pre-treated on an onshore facility for removal of mercury, acid gas, water and C5+ hydrocarbons, and then compressed and piped to an offshore platform for further compression and cooling before being transferred to a floating liquefaction, storage and offloading vessel for liquefaction of the natural gas.

A system for removing freezing components from a feed gas includes a heavy hydrocarbon removal heat exchanger and a scrub device. The scrub device includes a scrub column that receives a cooled feed gas stream from the heat exchanger and a reflux separation device. Vapor from the scrub column is directed to the heat exchanger and cooled to create a reflux stream that includes a liquid component. This reflux stream is directed to the reflux separation device and a resulting liquid component stream is used to reflux the column. Vapor from the reflux separation device is expanded and directed to the heat exchanger, where it provides refrigeration, and a processed feed gas line.

The present invention relates to a method of cooling and separating a hydrocarbon stream: (a) passing an hydrocarbon feed stream (7) through a first cooling and separation stage to provide a methane enriched vapour overhead stream (110) and a methane depleted liquid stream (10); (b) passing the methane depleted liquid stream (10) to a fractionation column (200) to obtain a bottom condensate stream (210), a top stream enriched in C1-C2 (220) and a midstream enriched in C3-C4 (230), (c) cooling the upper part of the fractionation column (201) by a condenser (206), (d) obtaining a split stream (112) from the methane enriched vapour overhead stream (110) and obtaining a cooled split stream (112) by expansion-cooling the split stream (112), (e) providing cooling duty to the top of the fractionation column (201) using the cooled split stream (112).

Described herein are systems and processes to produce liquefied nitrogen (LIN) using liquefied natural gas (LNG) as the refrigerant. The LIN may be produced by indirect heat exchange of at least one nitrogen gas stream with at least two LNG streams within at least one heat exchanger where the LNG streams are at different pressures.