Operable and efficient distillation schemes for multicomponent separations

摘要

The present invention teaches an efficient and easier to operate distillation system to separate mixtures containing three or more components into streams enriched in one of the components. In this invention, a liquid stream enriched in the least volatile component is withdrawn from the bottom of one distillation column while a vapor stream enriched in the most volatile component is withdrawn from the top of another distillation column. Of these two distillation columns, the pressure of the distillation column with the bottom liquid enriched in the least volatile component is higher; and this higher pressure distillation column transfers at least two vapor streams from different locations to either one or more other distillation columns within the distillation system. For a ternary mixture, both the vapor streams are transferred to the distillation column with the top vapor enriched in the most volatile component. In the preferred mode, at least one of the vapor transfer is part of a two-way communication between the two columns, i.e., in addition to the transfer of the vapor stream, a return liquid stream is implemented between the same locations of the two columns. This invention allows the flow of all vapor streams from a higher pressure column to a lower pressure column and thereby does not suffer with the operating pressure constraints of the prior art efficient processes.