| 摘要 |
Process for distillatively separating a liquid mixture containing at least two miscible volatile components having different boiling points using low-grade heat and, if necessary, low-grade cooling. Distillation is carried out at a pressure sufficiently low to cause the mixture at the bottom of the distillation column to boil below the temperature of the low-grade heat supplied and condensation of at least a portion of the vapor fraction is carried out at a pressure which permits using available cooling liquid. Condensed liquid is returned as reflux to the distillation column at a temperature and pressure essentially equal to the temperature and pressure prevailing near the top of the column. The progressive increase of vapor recompression in the system makes it possible to provide an increasing proportion of the energy to the system in the form of electrical energy, up to the total energy requirement. The process and apparatus of this invention are particularly suited to separating ethyl alcohol from dilute aqueous mixtures, where the formation of the ethyl alcohol azeotrope can be reduced or eliminated.
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