Apparatus, systems, and methods use cryogenic liquids such as, for example, liquefied natural gas and liquefied air or liquefied air components to store thermal energy. The cryogenic liquids may be produced using electrically powered liquefaction methods, for example, using excess electric power during periods of over-generation on the electric grid.

A system for the regeneration of nitrogen energy within a closed loop cryogenic system is described. A liquid nitrogen storage is provided in fluid communication with a first flow line. A pump pumps liquid nitrogen from the liquid nitrogen storage to the first flow line. At least one cryogenic cooling loop is provided in fluid communication with the first flow line. The cryogenic cooling loop has an nitrogen intake and a nitrogen outlet with the nitrogen outlet being positioned downstream of the nitrogen intake. The cryogenic cooling loop has a heat exchanger between the nitrogen intake and the nitrogen outlet. A turbo expander used for re-cooling the nitrogen flowing through the first flow line and the at least one cryogenic cooling loop has an inlet and an outlet. The inlet is provided in fluid communication with the first flow line. The turbo expander is connected to a power source. A second flow line connects the outlet of the turbo expander to the liquid nitrogen storage.

The invention relates to an integrated process and apparatus for liquefaction of natural gas and recovery of natural gas liquids. In particular, the improved process and apparatus reduces the energy consumption of a Liquefied Natural Gas (LNG) unit by using a portion of the already cooled overhead vapor from a fractionation column from an NGL (natural gas liquefaction) unit to, depending upon composition, provide, for example, reflux for fractionation in the NGL unit and/or a cold feed for the LNG unit, or by cooling, within the NGL unit, a residue gas originating from a fractionation column of the NGL unit and using the resultant cooled residue gas to, depending upon composition, provide, for example, reflux/feed for fractionation in the NGL and/or a cold feed for the LNG unit, thereby reducing the energy consumption of the LNG unit and rendering the process more energy-efficient.

A process of liquefying a natural gas stream in a liquefied natural gas facility is provided. The process includes cooling the natural gas stream in a first refrigeration cycle to produce a cooled natural gas stream. The process also includes cooling the cooled natural gas stream in a first chiller of a second refrigeration cycle, the cooled natural gas stream exiting the first chiller at a first pressure. The process further includes cooling the cooled natural gas stream in a first core of a second chiller of the second refrigeration cycle. The process yet further includes cooling a refrigerant of a refrigerant recycle stream separate from the cooled natural gas stream in a second core of the second chiller of the second refrigeration cycle, wherein the refrigerant recycle stream enters the second chiller at a second pressure that is lower than the first pressure of the cooled natural gas stream.

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.

Provided is a liquefied gas treatment system for a vessel, which includes a cargo tank storing liquefied natural gas (LNG), and an engine using the LNG as fuel. The liquefied gas treatment system includes: a compressor line configured to compress boil-off gas (BOG) generated in the cargo tank by a compressor and supply the compressed BOG to the engine as fuel; a high pressure pump line configured to compress the LNG stored in the cargo tank by a pump and supply the compressed LNG to the engine as fuel; and a heat exchanger configured to liquefy a part of BOG, which is compressed by the compressor, by exchanging heat with BOG that is discharged from the cargo tank and transferred to the compressor.

An apparatus for using nitrogen within a closed loop cryogenic system is described. A cryochamber is provided that has a first nitrogen flow line with an inlet for connection to a nitrogen source and an outlet. At least one cryogenic cooling loop is provided that has a nitrogen inlet and a nitrogen outlet. The nitrogen inlet and outlet are in fluid communication with the first nitrogen flow line. The nitrogen inlet is positioned upstream of the nitrogen outlet. A heat exchanger is provided on the at least one cryogenic cooling loops through which the nitrogen passes. The heat exchanger has a fluid inlet and a fluid outlet. A turbo expander is in fluid communication with the outlet of the first nitrogen flow line and the nitrogen source. The turbo expander re-cools the nitrogen that passes through the first flow line and the at least one cryogenic cooling loop.

A natural gas liquefaction process combined with a synthesis gas production process. At least one part of the heat source required in the synthesis gas production process is provided by at least a portion of the regeneration stream utilized to pretreat the natural gas to be liquefied.

A method for improved operation of a natural gas liquids stabilizer column, particularly a small-scale, is provided. The method can include the steps of: introducing a first feed stream comprising heavy hydrocarbons and natural gas to a stabilizer column to produce a top gas and a bottoms liquid, wherein the top gas has a higher concentration of natural gas as compared to the first feed stream, and the bottoms liquid has a higher concentration of heavy hydrocarbons as compared to the first feed stream; introducing a second feed stream into the stabilizer column, wherein the second feed stream has a higher concentration of natural gas as compared to the first feed stream, wherein the second feed stream is at a warmer temperature than the first feed stream when introduced into the stabilizer column, wherein the second feed stream is a gaseous stream; withdrawing the top gas from a top portion of the stabilizer column; withdrawing the bottoms liquid from a bottom portion of the stabilizer column; and sending at least a portion of the bottoms liquid to a liquid storage tank.

A method of cooling a boil off gas stream from a liquefied cargo (50a) in a floating transportation vessel is described. The method comprises: compressing a boil off gas stream in two or more stages of compression to provide a compressed BOG discharge stream; cooling the compressed BOG discharge stream against one or more first coolant streams to provide a first cooled compressed BOG stream; cooling the first cooled compressed BOG stream against at least one second coolant stream to provide a second cooled compressed BOG stream; providing a vessel fuel stream from the liquefied cargo; using the vessel fuel stream as a coolant stream to cool either the compressed BOG discharge stream, or the first cooled compressed BOG stream, or both said streams.