PURPOSE: To easily produce anhydrous alcohol having a purity higher than a specific level and useful from industrial viewpoint while saving energy consumption by carrying out pressurized extractive distillation of raw material composed mainly of ethanol and water using propane as an extraction solvent.
CONSTITUTION: The space in the 1st distillation column 1 is maintained at a temperature and pressure to enable the coexistence of the liquid and gas of propane. Raw materials 2 composed mainly of ethanol and water are supplied to the middle part of the column 1 and propane solvent 15, 16 is supplied to the column top. At the same time, essentially anhydrous ethanol and liquid propane 8 are extracted from the lower part of the column 1 and propane vapor and water essentially free from ethanol 3 are taken out from the top. Anhydrous ethanol having a purity of ≥99wt.% can be easily produced from the above raw materials by this process. The energy consumption can be remarkably reduced by pressurizing (4) the upper gaseous phase 3, etc., of the column 1, utilizing the compression heat as a heat source of the reboiler 8 of the 1st distillation column and refluxing the gaseous phase to the top of the above column 1, etc.
TANIMOTO TETSUYA
KANO YOSHIKAZU
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