Operable and efficient distillation schemes for multicomponent separations

摘要

Mixtures (10) containing three or more components (A, B, C) are distilled into respective streams 70,80,90 enriched in one of the components in a distillation column system in which a liquid stream (88) enriched in the least volatile component (C) is withdrawn from the bottom of one distillation column(100) while a vapor stream (68) enriched in the most volatile component (A) is withdrawn from the top of another distillation column (200). The pressure of the distillation column (100) with the bottom liquid enriched in the least volatile component (c) is higher than at a corresponding location in the other distillation column (200) to facilitate transfer of at least two vapor streams (32,50) from different locations to either one or more other distillation columns within the distillation system. For a ternary mixture, both the vapor streams (32,50) are transferred to the distillation column (200) with the top vapor enriched in the most volatile component. In the preferred mode, at least one of the vapor transfer (50) is part of a two-way communication (50,52) between the two columns (100,200) whereby, in addition to the transfer (50) of the vapor stream, a return liquid stream (52) is implemented between the same locations of the two columns.