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 process for co-producing a liquid oxygen and a liquefied hydrocarbon stream, including introducing a gaseous hydrocarbon stream and a gaseous nitrogen stream into a liquefier, thereby producing a liquefied hydrocarbon stream and a liquid nitrogen stream, liquefying a gaseous oxygen stream, wherein at least a portion of the required refrigeration is obtained from the liquid nitrogen stream. Wherein the liquefied hydrocarbon stream and the liquefied gaseous oxygen stream have mass flow rates. The liquid oxygen stream may be produced in an aft separation unit, wherein at least a portion of the required refrigeration is obtained from the liquid nitrogen stream.

Disclosed is a low-temperature refrigeration device comprising a working circuit that forms a loop and contains a working fluid, the device further comprising a cooling exchanger for extracting heat from at least one member by exchanging heat with the working fluid, the working circuit forming a cycle comprising, connected in series: a compression mechanism, a cooling mechanism, an expansion mechanism and a heating mechanism, wherein the mechanism for cooling the working fluid and the heating mechanism comprise a common heat exchanger in which the working fluid flows in opposite directions in two separate transit portions of the circuit according to whether it is cooled or heated, the device being designed to ensure equal mass flow rates in the two transit portions in the common heat exchanger, the device also comprising a bypass for bypassing one of the two transit portions, said bypass comprising a bypass valve which, in the open state, changes the mass flow rate in one of the two transit portions.

A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gasses put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self produced liquid nitrogen, pump it up to a runnable 420 psig pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.

The present invention pertains to a cooling method for liquefying a feed gas, comprising the steps of providing a cooling cycle with a refrigerant stream; dividing the refrigerant stream into a first partial stream and a second partial stream; expanding the first partial stream in a first expansion device; and transferring cooling energy from the expanded first partial stream to a feed gas stream to be cooled, particularly comprising hydrogen and/or helium. Further the method comprises the steps of guiding the expanded first partial stream to a suction inlet of an ejector; and guiding the second partial stream to a propellant inlet of the ejector such that, upon expanding the second partial stream in the ejector, the expanded first partial stream is compressed and merged with the expanded second partial stream.

The invention relates to a method for condensing a gas, wherein the gas is subjected to cooling in indirect heat exchange with a refrigerant and at least part of the refrigerant is subjected, after the heat exchange with the gas, to compression by means of a drive (GT1) that produces waste heat and to a partial or complete condensing process. After the partial or complete condensing process, a first portion of the refrigerant is subjected to the heat exchange with the gas and a second portion of the refrigerant is subjected, in succession, to pressurization, heating by means of the waste heat of the drive (GT1) and work-performing expansion and thereafter is fed back to the partial or complete condensing process. The invention further relates to a corresponding system.

Liquefier arrangements configured for co-production of both liquid natural gas (LNG) and liquid nitrogen (LIN) configured to operate in two distinct operating modes are provided.

The present invention relates to a refrigerant composition. According to the invention it is envisioned that the composition comprises comprising an inert gas selected from nitrogen, argon, neon and a mixture thereof, and a mixture of at least two C.sub.1-C.sub.5 hydrocarbons. The present invention further relates to the use of the refrigerant composition in a method for liquefying a gaseous substance, particularly hydrogen or helium.

Provided is a natural gas liquefaction apparatus including: a cryogenic heat exchanger through which natural gas passes through and is liquefied into liquefied natural gas (LNG) through heat exchange with a first refrigerant and a second refrigerant; a first refrigerant cycle through which the first refrigerant circulates, which has some paths passing through the cryogenic heat exchanger to perform heat exchange, and which has a path of the first refrigerant divided into a plurality of paths after performing heat exchange at the cryogenic heat exchanger and performs expansion and pre-compression of the first refrigerant; and a second refrigerant cycle through which the second refrigerant circulates and which has some paths passing though the cryogenic heat exchanger.

A method of producing LNG. According to the method, a natural gas stream is compressed using first and second compressors. A cooler cools the natural gas stream so that the second compressor produces a cooled, compressed natural gas stream, which is liquefied in a liquefaction process. The liquefaction process uses a refrigerant compressor configured to compress a stream of refrigerant used to chill, condense, or liquefy the cooled, compressed natural gas stream. Using a heat recovery steam generation (HRSG) system, heat is recovered from a power source of the refrigerant compressor. A stream of pressurized steam is generated from the recovered heat. At least one of the first and second compressors is powered using at least part of the stream of pressurized steam.