Disclosed is a re-liquefying device using a boil-off gas as a cooling fluid so as to re-liquefy the boil-off gas generated from a liquefied gas storage tank provided in a ship. A boil-off gas re-liquefying device for a ship comprises: a multi-stage compression unit for compressing boil-off gas generated from a liquefied gas storage tank; a heat exchanger in which the boil-off gas generated from the storage tank and the boil-off gas compressed exchange heat; a vaporizer for heat exchanging the boil-off gas cooled by the heat exchanger and a separate liquefied gas supplied to a fuel demand source of a ship, and thus cooling the boil-off gas; an intermediate cooler for cooling the boil-off gas that has been cooled by the heat exchanger; and an expansion means for branching a part of the boil-off gas, which is supplied to the intermediate cooler, and expanding the same.

The system for treating a gas deriving from the evaporation of a cryogenic liquid and supplying pressurized gas to a gas engine according to the invention comprises, on the one hand, from upstream to downstream, a reliquefaction unit (10) with compression means (11, 12, 13), a first heat exchanger (17) and expansion means (30), and, on the other hand, a pressurized gas supply line comprising, from upstream to downstream, a pump (48) for pressurizing the liquid and high-pressure vaporization means (61). The pressurized gas supply line has, upstream of the vaporization means (61), a bypass (57) for supplying a second heat exchanger (60) between, on the one hand, pressurized liquid of the supply line (56) and, on the other hand, a line (22) of the reliquefaction unit (10) downstream of the first exchanger and upstream of the expansion means (30).

A booster system includes: a cooling temperature regulating unit configured to regulate a temperature of an intermediate supercritical pressure liquid cooled and generated by a main cooling unit on upstream of a pump unit according to a flow rate of a supplied cooling medium; and a pressure detection unit configured to detect inlet pressure of the intermediate supercritical pressure liquid on an inlet side of the pump unit and detect outlet pressure of a target supercritical fluid on an outlet side of the pump unit. The cooling temperature regulating unit controls the flow rate of the cooling medium based on a pressure difference between the inlet pressure and the outlet pressure or a pressure ratio between the inlet pressure and the outlet pressure.

A proposed method provides a fueled power output augmentation of the liquid air energy storage (LAES) with zero carbon emissions of its exhaust. It combines the production of liquid air using a low-demand power from the renewable or/and conventional energy sources and the recovery of stored air for production of on-demand power in the fueled supercharged reciprocating internal combustion engine (RICE) and associated expanders. An integration between the LAES and RICE makes possible to recover the RICE exhaust energy for increase in power produced by the expanders of LAES and to use a cold thermal energy of liquid air being re-gasified at the LAES facility for cryogenic capture of CO.sub.2 emissions from the RICE exhaust.

Systems and processes for natural gas processing, liquefaction, and storage are described. The systems and processes include one or more arrangements of features which are capable of liquefying all of the gas entering an inlet of the system or a portion of the entering gas. The portion of the entering gas that is liquefied can vary based on the pressure of an outlet of the system, which can be fixed or vary based on usage downstream.

A system, and a method for producing liquefied natural gas are provided. The system includes a heat exchanger, a first supersonic chiller, and a compression unit. The heat exchanger is for cooling a feed natural gas stream to obtain a cooled natural gas stream. The first supersonic chiller is for chilling the cooled natural gas stream to produce liquefied natural gas and output at least a portion of chilled gaseous natural gas to the heat exchanger to be heated to obtain a heated natural gas stream. The compression unit is for compressing the heated natural gas stream from the heat exchanger and providing a compressed natural gas stream to the heat exchanger to be cooled together with the feed natural gas stream by heat exchanging with the at least a portion of the chilled gaseous natural gas.

In a cryogenic combined cycle power plant electric power drives a cryogenic refrigerator to store energy by cooling air to a liquid state for storage within tanks, followed by subsequent release of the stored energy by first pressurizing the liquid air, then regasifying the liquid air and raising the temperature of the regasified air at least in part with heat exhausted from a combustion turbine, and then expanding the heated regasified air through a hot gas expander to generate power. The expanded regasified air exhausted from the expander may be used to cool and make denser the inlet air to the combustion turbine. The combustion turbine exhaust gases may be used to drive an organic Rankine bottoming cycle. An alternative source of heat such as thermal storage, for example, may be used in place of or in addition to the combustion turbine.

A ship comprising an engine is disclosed. The ship comprising an engine comprises: a self-heat exchanger which heat-exchanges boil-off gas discharged from a storage tank; a multi-stage compressor which compresses, in multi-stages, boil-off gas that passed through the self-heat exchanger after being discharged from the storage tank; a first decompressing device which expands one portion of boil-off gas that passed through the self-heat exchanger after being compressed by the multi-stage compressor; and a second decompressing device which expands the other portion of the boil-off gas that passed through the self-heat exchanger after being compressed by the multi-stage compressor, wherein the self-heat exchanger uses boil-off gas discharged from the storage tank and boil-off gas expanded by the first decompressing device as refrigerants for cooling boil-off gas compressed by the multi-stage compressor.

A method for producing liquefied natural gas and a stream of liquid nitrogen including step a): producing gaseous nitrogen in an air separation unit; step b): liquefying a stream of natural gas in a natural gas liquefaction unit including a main heat exchanger and a system for producing cold; step c): liquefying the nitrogen stream resulting from step a) in the main exchanger of the natural gas liquefaction unit in parallel with the liquefied natural gas in step b); wherein all the cold necessary for liquefying the stream of nitrogen and for liquefying the natural gas is supplied by the system for producing cold of the natural gas liquefaction unit.

Power recovery sub-systems, cryogenic energy storage systems, and methods of capturing, storing, and re-using thermal energy are disclosed.