Abstract:
The present invention relates to a method for liquefying a natural gas primarily including methane, in which said natural gas to be liquefied is liquefied by performing the following concomitant steps: (a) circulating said natural gas to be liquefied that is circulating in three heat exchangers which are mounted in series and in which the gas is cooled to T3, T3 being no higher than the liquefaction temperature of said natural gas at atmospheric pressure; (b) the closed-circuit circulation of at least: a first stream of coolant gas at a pressure P1 that is lower than P3, which is entering the third exchanger and leaving said first exchanger, said first stream being obtained by expanding, in a first expansion valve, a first portion of said second stream to P3, which is higher than P2, said second stream circulating parallel to said stream of natural gas while entering said first exchanger and leaving said second exchanger; and a third stream at a pressure P2 higher than P1 and lower than P3 circulating parallel to said first stream which is entering said second exchanger and exiting said first exchanger, and which is obtained by expanding, in a second expansion valve, a second portion of said second stream exiting said first exchanger; and (c) said second stream of coolant gas at the pressure P3, which is obtained by compression by means of at least two first and second compressors arranged in series and coupled to said first and second expansion valves.
Abstract:
The present invention relates to a method for liquefying a natural gas primarily including methane, in which said natural gas to be liquefied is liquefied by performing the following concomitant steps: (a) circulating said natural gas to be liquefied that is circulating in three heat exchangers which are mounted in series and in which the gas is cooled to T3, T3 being no higher than the liquefaction temperature of said natural gas at atmospheric pressure; (b) the closed-circuit circulation of at least: a first stream of coolant gas at a pressure P1 that is lower than P3, which is entering the third exchanger and leaving said first exchanger, said first stream being obtained by expanding, in a first expansion valve, a first portion of said second stream to P3, which is higher than P2, said second stream circulating parallel to said stream of natural gas while entering said first exchanger and leaving said second exchanger; and a third stream at a pressure P2 higher than P1 and lower than P3 circulating parallel to said first stream which is entering said second exchanger and exiting said first exchanger, and which is obtained by expanding, in a second expansion valve, a second portion of said second stream exiting said first exchanger; and (c) said second stream of coolant gas at the pressure P3, which is obtained by compression by means of at least two first and second compressors arranged in series and coupled to said first and second expansion valves.
Abstract:
The present invention relates to 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 said natural gas to be liquefied is liquefied by circulating said natural gas to be liquefied that is 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 means of 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 said cryogenic heat-exchanger at a temperature T3' that is lower than T3, T3 being the liquefaction temperature of said liquefied natural gas at said pressure P0 at the output of said cryogenic exchanger, characterised in that said coolant gas includes a mixture of nitrogen and at least one other component selected from among neon and hydrogen.
Abstract:
La présente invention a pour objet un procédé de liquéfaction d'un gaz naturel comprenant majoritairement du méthane, dans lequel on liquéfie ledit gaz naturel à liquéfier en réalisant les étapes concomitantes suivantes de : (a) circulation dudit gaz naturel à liquéfier circulant dans 3 échangeurs thermiques montés en série dans lesquels il est refroidit à T3, T3 étant inférieure ou égale à la température de liquéfaction dudit gaz naturel à pression atmosphérique, et (b) circulation à circuit fermé d'au moins: - un premier flux de gaz réfrigérant à une pression PI inférieure à P3 entrant dans le troisième échangeur et sortant dudit premier échangeur, ledit premier flux étant obtenu par détente dans un premier détendeur d'une première partie d'un dit deuxième flux à P3 supérieure à P2, ledit deuxième flux circulant à co-courant dudit flux gaz naturel en entrant dans ledit premier échangeur et sortant dudit deuxième échangeur, et - un troisième flux à une pression P2 supérieure à PI et inférieure à P3 circulant à co-courant dudit premier flux, entrant dans ledit deuxième échangeur et sortant dudit premier échangeur, obtenu par détente dans un deuxième détendeur d'une deuxième partie dudit deuxième flux sortant dudit premier échangeur, (c) ledit deuxième flux de gaz réfrigérant à la pression P3 étant obtenu par compression par au moins deux premier et deuxième compresseurs disposés en série et couplés auxdits premier et deuxième détendeurs.
Abstract:
La présente invention a pour objet un procédé de liquéfaction d'un gaz naturel comprenant majoritairement du méthane, de préférence, au moins 85% de méthane, les autres composants comprenant essentiellement de l'azote et des alcanes en C-2 à C-4, dans lequel on liquéfie le dit gaz naturel à liquéfier par circulation dudit gaz naturel à liquéfier circulant à une pression PO supérieure ou égale à la pression atmosphérique (Patm.)/ de préférence PO étant supérieure à la pression atmosphérique, dans au moins 1 échangeur de chaleur cryogénique (EC1, EC2, EC3) par circulation en circuit fermé à contre-courant en contact indirect avec au moins un flux de gaz réfrigérant restant à l'état gazeux comprimé à une pression PI entrant dans le dit échangeur cryogénique à une température T3' inférieure à T3, T3 étant la température de liquéfaction du dit gaz naturel liquéfié à la dite pression PO en sortie dudit échangeur cryogénique, caractérisé en ce que le dit gaz réfrigérant comprend un mélange d'azote et d'au moins un autre constituant choisi parmi le néon et l'hydrogène.