Abstract: In this method, the LNG stream (11) is cooled using a refrigerating fluid (83) in a first heat-exchanger (19). The refrigerating fluid (83) is subjected to a second semi-open refrigeration cycle (21) which is independent of the first cycle (15). The method comprises a step for introducing the stream (59) of sub-cooled LNG into a distillation column (49) and a step for recovering a stream (69) of gas at the top of the column (49). The second refrigeration cycle (21) comprises a step for forming a stream (73) of refrigerating fluid from a portion of the top stream (69) of gas, a step for compressing the stream of refrigerating fluid (73) to a high pressure, then a step for expanding a portion (81) of the stream (75) of compressed refrigerating fluid in order to form a substantially liquid sub-cooling stream (83). The substantially liquid stream (83) is evaporated in the first heat-exchanger (19).

Abstract: The invention relates to a method for fractionating a gas produced by the pyrolysis of hydrocarbons (1) for the recovery of C2 and higher hydrocarbons, in particular ethylene and ethane, comprising an operation (70) for compressing and drying gas (1) as a result of it passing into a series of compressors (3, 10, 17, 24, 36), an operation (80) for progressively cooling and partially liquefying the gas produced by compression and drying operation (70) as a result of it successively passing into a cryogenic exchanger (62), and a distillation operation (90) in a column (64), and the corresponding installation. According to the invention, cryogenic exchanger (62) is cooled by at least one cooling liquid (400) which is liquid natural gas (LNG).

Abstract: The invention relates to a method of separating a dry feed gas (1) containing mostly methane, ethane and propane into a first product (17), called the treated gas, which is relatively more volatile, and a second product (34), called fraction C2 plus, which is relatively less volatile. The inventive method comprises: (i) an operation involving the cooling of the supply gas (1) into a cooled gas (2); (ii) an operation whereby the cooled gas (2) from operation (i) is separated and treated; and (iii) distillation in a distillation device (C3). The invention also relates to the corresponding installation. According to the invention, the distillation device (C3) comprises at least first and second distillation columns, (C1) and (C2), which operate at different pressures.

Abstract: In this process, the LNG stream is sub-cooled with a refrigerating fluid in a first heat exchanger. This refrigerating fluid undergoes a closed second refrigeration cycle which is independent of the first cycle. The closed cycle comprises a phase of heating the refrigerating fluid in a second heat exchanger, and a phase of compressing the refrigerating fluid in a compression apparatus to a pressure greater than its critical pressure. It further comprises a phase of cooling the refrigerating fluid originating from the compression apparatus in the second heat exchanger and a phase of dynamically expanding of a proportion of the refrigerating fluid issuing from the second heat exchanger in a turbine. The refrigerating fluid is formed by a mixture of nitrogen-containing fluids.

Abstract: The invention concerns a method comprising: (a) a first step whereby natural gas (1) is subjected to a first refrigerating cycle to obtain cooled natural gas (4), and brought to a temperature less than 20° C. by a first coolant (201); a second step whereby the cooled natural gas (4) is subjected to a second refrigerating cycle wherein the cooled natural gas (4) is cooled and condensed by a second coolant (103) comprising methane, ethane, propane, and nitrogen. The second coolant (103) further contains ethylene, the total ethane and ethylene content being close to 50 mole %.

Abstract: This method comprises the cooling of the initial natural gas and its introduction into a column for recovering C2+ hydrocarbons. It comprises the recovery of the top stream from the column to form the treated natural gas, and the recovery of the bottom stream from the column for introducing it at a feed level of a fractionating column equipped with a top condenser. The column produces the said C3+ hydrocarbons at the bottom. The method comprises the recovery of the ethane rich stream from an intermediate level of the column located above the said feed level and the production of a secondary reflux stream from the said top condenser refluxed to the top of the recovery column.

Abstract: The invention concerns a method for refrigerating liquefied natural gas under pressure (1), comprising a first step wherein the LNG (1) is cooled, expanded and separated (a) in a first base fraction (4) which is collected, and (b) a first top fraction (3) which is heated, compressed in a compressor (K1) and cooled into a first compressed fraction (5) which is collected; a second compressed fraction (6) is drawn from the fuel gas (5), cooled then mixed with the cooled and expanded LNG (1). The invention is characterised in that it comprises a second step wherein the second compressed fraction (6) is compressed and cooled, and a flux is (8) drawn and cooled, expanded and introduced in the compressor (K1). The invention also describes other embodiments.

Abstract: The invention relates to a method of separating a dry feed gas (1) containing mostly methane, ethane and propane into a first product (17), called the treated gas, which is relatively more volatile, and a second product (34), called fraction C2 plus, which is relatively less volatile. The inventive method comprises: (i) an operation involving the cooling of the supply gas (1) into a cooled gas (2); (ii) an operation whereby the cooled gas (2) from operation (i) is separated and treated; and (iii) distillation in a distillation device (C3). The invention also relates to the corresponding installation. According to the invention, the distillation device (C3) comprises at least first and second distillation columns, (C1) and (C2), which operate at different pressures.

Abstract: The invention concerns a method comprising: (a) a first step whereby natural gas (1) is subjected to a first refrigerating cycle to obtain cooled natural gas (4), and brought to a temperature less than 20° C. by a first coolant (201); a second step whereby the cooled natural gas (4) is subjected to a second refrigerating cycle wherein the cooled natural gas (4) is cooled and condensed by a second coolant (103) comprising methane, ethane, propane, and nitrogen. The second coolant (103) further contains ethylene, the total ethane and ethylene content being close to 50 mole %.

Abstract: This process includes the following steps:

Abstract: The invention relates to a method for fractionating a gas produced by the pyrolysis of hydrocarbons (1) for the recovery of C2 and higher hydrocarbons, in particular ethylene and ethane, comprising an operation (70) for compressing and drying gas (1) as a result of it passing into a series of compressors (3, 10, 17, 24, 36), an operation (80) for progressively cooling and partially liquefying the gas produced by compression and drying operation (70) as a result of it successively passing into a cryogenic exchanger (62), and a distillation operation (90) in a column (64), and the corresponding installation.

Abstract: The invention concerns a method and an installation for refrigerating gas mixtures, for cryogenic separation of a pressurised gas (1) constituents. The method comprises a refrigerating cycle wherein a fluid (13) is separated in a separator tank (B2) into a less volatile fraction (4), for producing refrigeration at a relatively high first temperature in an exchanger (E1), and into a more volatile second fraction (5) for producing refrigeration at a relatively low temperature in an exchanger (E2). The heated and expanded fractions (4, 5) are brought together then compressed in a compressor (K1). A fraction (26) derived from said compressor (K1) is cooled to supply the fraction (13).

Abstract: The invention concerns a method for refrigerating liquefied natural gas under pressure (1), comprising a first step wherein the LNG (1) is cooled, expanded and separated (a) in a first base fraction (4) which is collected, and (b) a first top fraction (3) which is heated, compressed in a compressor (K1) and cooled into a first compressed fraction (5) which is collected; a second compressed fraction (6) is drawn from the fuel gas (5), cooled then mixed with the cooled and expanded LNG (1). The invention is characterised in that it comprises a second step wherein the second compressed fraction (6) is compressed and cooled, and a flux is (8) drawn and cooled, expanded and introduced in the compressor (K1). The invention also describes other embodiments.

Abstract: A process and apparatus for separation of a gas mixture. A process and an installation for cryogenic separation of the constituents of a natural gas under pressure in a first phase separator in which the constituents of each phase are separated in a distillation column. Part of the gaseous fraction from the top of the column is recycled into the highest stage of the column. The process also includes branching of part of a first top fraction from the first phase separator. The process also includes separation of a first bottom fraction from the first separator, in a second separator.

Abstract: A process for liquefaction of and nitrogen extraction from natural gas, an installation for implementation of the process, and gases obtained by this process. In the process, a first top fraction is cooled and liquefied, separated into a second top fraction which is relatively volatile and which provides gaseous nitrogen, and into a second bottom fraction which is withdrawn. The first bottom fraction is cooled in order to provide liquefied natural gas essentially free nitrogen.

Abstract: Process and installation for separation of a gas mixture, and gases obtained by this installation. The present invention pertains to a process and an installation for cryogenic separation of the constituents of a natural gas under pressure (14) by a first phase separator (B1) in which the constituents of each phase are separated in a distillation column (C1). Part of the gaseous fraction (5) from the top of the column (C1) is recycled into the highest stage of the column. The process also includes branching (9) of part of a first top fraction (3) from the first phase separator. The process also includes separation of a first bottom fraction (4) from the first separator, in a second separator (B2). Other modes of embodiment are also described.

Abstract: A process and apparatus for the purification of a gas, in particular natural gas, in order to eliminate mercaptans without the use of gas adsorption or cryogenic expansion processes. Natural gas, dried and cooled, is supplied to an absorption column under pressure, producing a head product of a purified gas, and a base product supplied to a fractionating column which separates the most volatile compounds, free from mercaptans, from a gasoline fraction of the natural gas. The mercaptans are eliminated at the head of at least one distillation column, producing a base end product consisting of a mixture of C5 hydrocarbons, heavier than and free from volatile mercaptans, partially mixed with the most volatile recompressed compounds of the natural gas. This mixture is cooled and sent by reflux to the absorption column.

Abstract: A method allowing a gaseous mixture such as a natural gas to be liquefied by using a first compressed coolant mixture M.sub.1, at least partially condensed by cooling with the aid of an external coolant fluid, then subcooled, expanded, and vaporized, and a second compressed coolant mixture, cooled with the aid of an external coolant fluid, then cooled by heat exchange with the first coolant mixture M.sub.1 during the first cooling stage (I), after which it is in an at least partially condensed state. The second partially condensed coolant mixture is sent without phase separation to a second cooling stage (II) where it is fully condensed, expanded, and vaporized at at least two pressure levels. The subcooled natural gas is expanded to form the LNG produced.

Abstract: A method of drying a gas making use of the distillation of a liquid desiccant, the method comprising the introduction of a stream of make-up liquid containing water and of an organic solvent miscible with water, the solvent being a more volatile solvent than water under the conditions of the method and forming no azeotropes with water, in an intermediate zone of an elongated vertical contact and fractional distillation zone.

Abstract: A self-refrigerated method of cryogenic fractionation and purification of gas and a heat exchanger for performing the method, wherein the gaseous fluid is treated in an exchanger forming a unitary assembly: it is partially condensed by cooling in a fifth and first circuits and the non-condensed gaseous fraction is re-heated in a second circuit, the required cold being supplied by the condensates which after having been sub-cooled in a third circuit and expanded in a valve are evaporating in a fourth circuit, the method permitting the purification of a gaseous fluid with several condensable components through cooling possibly in an exchanger with multiple channels for each circuit.