Method for ethane recovery, using a refrigeration cycle with a mixture of at least two coolants, gases obtained by said method, and installation therefor
OwnerHenri Paradowskiinventor
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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).
Claims11
A process for recovering the ethane contained in a pressurized gas (1) containing methane and C2 and higher hydrocarbons, operating a refrigerating cycle in which a relatively less-volatile first refrigerant (2) is compressed, cooled and expanded in order thereafter to be used for cooling said pressurized gas (1) to be separated or first separation products to a relatively high first temperature, and in which a relatively more-volatile second refrigerant (3) is compressed, cooled and expanded in order thereafter to be used for cooling at least second separation products obtained from said pressurized gas (1) to a relatively low second temperature *1, *2 characterized in that the first and second refrigerants (2, 3) are used as a mixture when they are compressed and cooled, in that this mixture then undergoes a separation into a first fraction (4) essentially containing the relatively less-volatile first refrigerant (2) and into a second fraction (5) essentially containing the relatively more-volatile second refrigerant (3), in that the first refrigerant is used in the form of the first fraction, for cooling to the relatively high first temperature, and in that the second refrigerant is used in the form of the second fraction, for cooling to the relatively low second temperature.
The process as claimed in any one of the preceding claims, characterized in that said first and second refrigerants (2, 3) are used as a mixture with a third refrigerant (12).
A methane-enriched gas obtained by the process as claimed in one of the preceding claims.
A plant for recovering the ethane contained in a pressurized gas (1) containing methane and C2 and higher hydrocarbons, this plant comprising means for compressing, cooling and expanding a relatively less-volatile first refrigerant (2), means for cooling, by means of the first refrigerant, said pressurized gas (1) to be separated or first separation products to a relatively high first temperature, and means for compressing, cooling and expanding a relatively more-volatile second refrigerant (3), means for cooling, by means of the second refrigerant (3), at least second separation products obtained from said pressurized gas (1) to a relatively low second temperature, characterized in that the first and second refrigerants (2, 3) are used as a mixture when they are compressed and cooled and in that this plant comprises means for this mixture to undergo a separation into a first fraction (4) essentially containing the relatively less-volatile first refrigerant (2) and into a second fraction (5) essentially containing the relatively more-volatile second refrigerant (3), the first refrigerant being used in the form of the first fraction for cooling to the relatively high first temperature and the second refrigerant being used in the form of the second fraction for cooling to the relatively low second temperature.
Dependencies are inferred from the claim text.