Cryogenic refrigeration device comprising a working circuit intended to cool a working fluid circulating in the said circuit, the working circuit comprising, arranged in series in a loop: a compression portion, a cooling portion, a portion with valve(s), an expansion portion and a reheating portion, in order to subject the working fluid to a recuperative working cycle comprising compression, then cooling, then expansion and then reheating to prepare for a new cycle, wherein the compression portion comprises at least one compressor having a linear piston driven by a linear motor, the expansion proportion comprises at least one expander with a linear piston, the portion with valve(s) comprises at least one regulating valve linearly actuated by a linear motor and controlled in order to supply or extract the working fluid from the at least one expansion piston.

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.

A method for producing liquefied natural gas (LNG) from a natural gas stream having a nitrogen concentration of greater than 1 mol %. At least one liquid nitrogen (LIN) stream is received at an LNG liquefaction facility. The LIN streams may be produced at a different geographic location from the LNG liquefaction facility. A natural gas stream is liquefied by indirect heat exchange with a nitrogen vent stream to form a pressurized LNG stream. The pressurized LNG stream has a nitrogen concentration of greater than 1 mol %. The pressurized LNG stream is directed to one or more stages of a column to produce an LNG stream and the nitrogen vent stream. The column has upper stages and lower stages. The LIN streams are directed to one or more upper stages of the column.

A method for exhaust waste energy recovery at the reciprocating gas engine-based polygeneration plant which includes supplying this plant with any on-site available methaneous gas, converting from 15 to 30% of supplied gas into electric or mechanical power and producing a liquefied methaneous gas (LMG) co-product from the other 85-70% of supplied gas, and thereby obviates a need for any specialized refrigeration equipment, refrigerants and fuel for LMG co-production at a rate of 0.4-0.6 ton/h for each MW of engine output and makes possible to increase the LMG co-production rate up to 0.9-1.1 t/MWh at the sacrifice of a fuel self-consumption minimized down to 1-2% of the amount of gas intended for liquefaction.

A liquefaction apparatus that automatically adjusts the load on the liquefaction apparatus correspondingly with an upper limit value of contracted power in different time slots, and which is capable of maximizing the amount of liquefied product produced and of achieving optimum operating efficiency is provided. In certain embodiments, the liquefaction apparatus can include: a production amount calculation unit 91 for obtaining an actual production amount of a liquefied product; a predicted power calculation unit 92 for obtaining a predicted power amount after a predetermined time has elapsed, on the basis of an integrated power value obtained by integrating a usage power; and a power demand control unit 93 for comparing the predicted power amount and a moving average of instantaneous power, and controlling a discharge flow rate of a compressor 3 in such a way as to come infinitely close to a target value, without exceeding the target value, and while using the larger value of the predicted power amount and the moving average of instantaneous power as a value being controlled.

Liquefaction of industrial gases or gas mixtures (hydrocarbon and/or non-hydrocarbon) uses a modified aqua-ammonia absorption refrigeration system (ARP) to chill the gas or gas mixture during the liquefaction process. The gas is compressed to above its critical point, and the heat of compression energy may be recovered to provide some or all of the thermal energy required to drive the ARP. A Joule Thomson (JT) adiabatic expansion process results in no requirement for specialty cryogenic rotating equipment. The aqua-ammonia absorption refrigeration system includes a vapour absorber tower (VAT) that permits the recovery of some or all of the heat of solution and heat of condensation energy in the system when anhydrous ammonia vapour is absorbed into a subcooled lean aqua-ammonia solution. The modified ARP with VAT may operate at pressures as low as 10 kPa, and the ammonia gas chiller may operate at temperatures as low as −71° C.

A gas processing system according to an embodiment of the present invention controls inflow fuel pressure of a low pressure demand source according to an operation or a non-operation of a high pressure demand source and the low pressure demand source.

A method and system for liquefying a natural gas feed stream and removing nitrogen therefrom.

In an aspect, a system comprises a water stream in fluid communication with an electrolyzer; the electrolyzer comprising an anode and a cathode side chamber; a deep space oxygen radiator in fluid communication with the anode side chamber of the electrolyzer; a cryogenic heat exchanger comprising an oxygen storage tank in fluid communication with the deep space oxygen radiator; an electrochemical hydrogen compressor in fluid communication with the cathode side chamber; a hydrogen storage tank in fluid communication with the electrochemical hydrogen compressor via a cooled hydrogen stream; wherein at least a portion of the cooled hydrogen stream is in a first fluid communication with an expansion valve and the cryogenic heat exchanger; wherein the hydrogen storage tank is in a second fluid communication with the electrochemical hydrogen compressor via a warmed hydrogen stream; and wherein the cryogenic heat exchanger is in fluid communication with the warmed hydrogen stream.

Disclosed is a method of discharging lubricant oil from a BOG reliquefaction system configured to reliquefy BOG by compressing the BOG by a compressor, cooling the compressed BOG through heat exchange with non-compressed BOG by a heat exchanger, and reducing a pressure of fluid cooled through heat exchange by a pressure reducer. In the lubricant oil discharge method, the compressor comprises at least one oil-lubrication type cylinder and it is determined that it is time to discharge condensed or solidified lubricant oil, if at least one of preset conditions is satisfied.