Patent ID: 6358399
Filing Date: 2002-03-19
Classification: C07C,C10G

Abstract:
A process for separating a mixture that consists essentially of ethane and ethylene from a hydrocarbon steam-cracking effluent, whereby the effluent comprises hydrogen, methane, ethylene, ethane, acetylene, methylacetylene, propadiene, propene and hydrocarbons with at least 4 carbon atoms, whereby the process is characterized in that:said feedstock is absorbed in at least one absorption column (7) by a cooled solvent phase under suitable absorption conditions, and a gaseous phase that contains in particular hydrogen and methane is recovered at the top of the column and a partly liquid phase (12) is recovered at the bottom of the column that contains the solvent that is enriched with ethylene, ethane, acetylene, methylacetylene, propadiene, propene and hydrocarbons with at least 4 carbon atoms; the liquid phase is hydrogenated in at least one catalytic hydrogenation zone (15) in the presence of hydrogen and a hydrogenation catalyst under suitable hydrogenation conditions, and at least one liquid phase that is at least partly hydrogenated and that essentially does not contain acetylene is recovered; the following stage sequence is carried out: the liquid phase that is at least in part hydrogenated is regenerated in at least a first distillation column (70), and there is recovered at the top of the column a gaseous phase (71) that is condensed to separate a vapor phase (74) and a phase (75) that essentially consists of hydrocarbons with at least two carbon atoms that are partly recycled as reflux, and at the bottom of the column a regenerated solvent phase (26, 9); remaining portion (76) of the phase that consists essentially of hydrocarbons with at least two carbon atoms is circulated in at least a second distillation column (77), and there are recovered at the top a second phase (78) that is condensed to separate a second light gaseous phase (81); by a lateral draw-off, said mixture (83) that consists essentially of ethane and ethylene; and at the bottom of the column, a hydrocarbon-enriched fraction (84) with at least 3 carbon atoms. Solvent phase (26) is cooled (13, 28), and it is at least partly recycled in absorption column (7).