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 process for liquefying methane-rich gases comprising providing a stream of feed methane-rich gas at a pressure of from 40 bar to 120 bar and containing higher hydrocarbons; providing a stream of methane-rich recycle gas at a pressure of from 40 bar to 120 bar; mixing the feed gas with a first part of the recycle gas; passing the resulting mixture to a gas expander, the expander outlet having a pressure of between 3 bar and 50 bar, so as to form a mixture of vapor and a condensed liquid containing higher hydrocarbons; separating the expander outlet stream into a liquid stream and a vapor stream; reheating and compressing said vapor stream to a pressure of from 40 bar to 120 bar to form a first constituent of the above-said recycle gas; cooling a second part of the said recycle gas to a temperature higher than the outlet temperature of the said expander; passing said cooled second part of the recycle gas into a liquefaction unit to form liquefied methane and a second vapor stream; reheating and compressing said second vapor stream to a pressure of from 40 bar to 120 bar to form a second constituent of the above-said recycle gas.

The method for producing liquid hydrogen can include the steps of: introducing pressurized natural gas from a high pressure natural gas pipeline to a gas processing unit under conditions effective for producing a purified hydrogen stream; and introducing the purified hydrogen stream to a hydrogen liquefaction unit under conditions effective to produce a liquid hydrogen stream, wherein the hydrogen liquefaction unit provides a warm temperature cooling and a cold temperature cooling to the purified hydrogen stream, wherein the warm temperature cooling is provided by utilizing letdown energy of a pressurized stream selected from the group consisting of a nitrogen stream sourced from a nitrogen pipeline, a natural gas stream sourced from the high pressure natural gas pipeline, an air gas sourced from an air separation unit, and combinations thereof, wherein the cold temperature is provided by utilizing letdown energy of the purified hydrogen stream.

Systems and methods for increasing the efficiency of liquefied natural gas (LNG) production, as well as facilitating coproduction of electric power, and compressed natural gas (CNG) are described. The systems and methods facilitate producing an intermediate LNG at a higher temperature, recovering refrigeration from flash gas and boil-off gas from the LNG, using flash-gas and boil-off gas as fuel to generate electric power, and providing LNG, CNG, and electric power to a vehicle fueling facility.

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.

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.

A system for reliquefying a boil off gas generated in a storage tank includes a first compressor compressing a partial amount (hereinafter, referred to as fluid a) of boil off gas discharged from the storage tank, a second compressor compressing another partial amount (hereinafter, referred to as fluid b) of boil off gas discharged from the storage tank, a second expanding unit expanding a partial amount (hereinafter, referred to as fluid c) of a flow formed as the fluid a and the fluid b join, a heat-exchanger cooling another partial amount (hereinafter, referred to as fluid d) of the flow formed as the fluid a and the fluid b join, and a first expanding unit expanding the fluid d cooled by the heat-exchanger, wherein the heat-exchanger heat-exchanges the fluid d with the fluid c as a coolant expanded by the second expanding unit to cool the fluid d.

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.

A method for liquefying gas involving pre-treating the gas stream in a pre-treater to remove impurities, and then passing the gas stream through a first flow path of a first heat exchanger to lower a temperature of the gas stream. The gas stream is then passed through the gas expansion turbine to lower a pressure of the gas stream and further decrease the temperature of the gas stream. The gas stream is then passed into a primary separator to separate the gas stream into a liquid stream and a cold gas stream. The liquid stream is collected. Selected quantities of the cold gas stream are passed through a second flow path of the first heat exchanger whereby a heat exchange takes place to cool the gas stream flowing through the first flow path to maintain the temperature of the gas stream entering the gas expansion turbine at a temperature which promotes the production of liquids.

A proposed method for thermally assisted electric energy storage is intended for increase in round-trip efficiency through recovery of waste heat energy streams from the co-located power generation and industrial facilities, combustion of renewable or fossil fuels, or harnessing the renewable energy sources. In the charge operation mode, it is achieved by superheating and expansion of recirculating air stream in the liquid air energy storage with self-producing a part of power required for air liquefaction. In the discharge operation mode, it is attained through the repeated use of a stream of discharged air for production of an additional power in auxiliary discharge cycle.