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 method for controlling the flow of natural gas and refrigerant in the main heat exchanger of a natural gas liquefaction facility. The method provides for the automated control of a flow rate of a natural gas feed stream through a heat exchanger based on one or more process variables and set points. The flow rate of refrigerant streams through the heat exchanger is controlled by different process variables and set points, and is controlled independently of the flow rate of the natural gas feed stream.

A method for liquefying a natural gas primarily including methane, preferably at least 85% of methane, the other components essentially including nitrogen and C2-C4 alkanes, in which the natural gas to be liquefied is liquefied by circulating at a pressure P0 no lower than the atmospheric pressure (Patm), P0 preferably being higher than the atmospheric pressure, in at least one cryogenic heat-exchanger (EC1, EC2, EC3) by a counter-current closed-circuit circulation in indirect contact with at least one stream of coolant gas remaining in the compressed gaseous state at a pressure P1 that is entering the cryogenic heat-exchanger at a temperature T3′ that is lower than T3, T3 being the liquefaction temperature of the liquefied natural gas at the pressure P0 at the output of said cryogenic exchanger, characterized in that the coolant gas includes a mixture of nitrogen and at least one other component selected from among neon and hydrogen.

Process for eliminating the evaporation of a liquefied natural gas stream during the transfer thereof into a storage facility, comprising the following steps: Step a): liquefaction, by means of a refrigeration cycle, of a natural gas stream and of a nitrogen stream in a main heat exchanger; Step b): cooling of the liquefied natural gas stream from step a) in a second heat exchanger by circulation of said liquefied natural gas stream countercurrent to a liquid nitrogen flow that is vaporized while cooling said liquefied natural gas stream; wherein the liquid nitrogen flow used in step b) is from step a).

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.

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.

Process for eliminating the evaporation of a liquefied natural gas stream during the transfer thereof into a storage facility, comprising the following steps: Step a): liquefaction, by means of a refrigeration cycle, of a natural gas stream and of a nitrogen stream in a main heat exchanger; Step b): cooling of the liquefied natural gas stream from step a) in a second heat exchanger by circulation of said liquefied natural gas stream countercurrent to a liquid nitrogen flow that is vaporized while cooling said liquefied natural gas stream; wherein the liquid nitrogen flow used in step b) is from step a).

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.