METHOD OF PRODUCING THREE SEPARATE STREAMS OF METHANOL AND ETHANOL, PROPANOL, AND ISOBUTANOL Russian patent published in 2000 - IPC

FIELD: chemical engineering. SUBSTANCE: invention relates to separation of alcohol mixture prepared from carbon monoxide and hydrogen (synthesis gas) and used as high-octane fuel additives. Mixture coming into separation unit contains, wt %: methanol 20-80, ethanol 0.1-10, propanol 0.1-20, isobutanol 2-40, and water 0.1-50, and low- and high-boiling organics - the balance. Separation is carried out in three rectification columns. From top part of the first column, waterless stream 1 largely consisting of methanol and ethanol is run off as side-cut distillate. Second side-cut distillate is also run off from the first column at point located below the raw material introduction point. This distillate is cooled and separated into organic and water phases. The former is returned into the bottom part of column as recycling stream. From the first column still, liquid stream largely containing propanol, isobutanol and other high-boiling compounds with methanol and ethanol traces is tapped and directed into second column. From top part of the second column, stream 2 largely consisting of propanol with small admixtures of initial alcohols and water is run off. Stream 3 containing up to 95% isobutanol with admixtures of high- boiling compounds is run off from bottom part of the second column. Third column serves for separation of water phase of lower distillate from the first column to give top distillate containing alcohols and other organics to return into the first column. Stream from the bottom part of this column mainly consists of water. Pressures in the columns and separator vary from 30 to 500 kPa. EFFECT: improved qualitative composition of alcohols meeting requirements for mixtures of oxygen- containing high-octane compounds. 12 cl, 1 dwg