| 摘要 |
<p>A process is disclosed for the dehydration of a mixture of methanol and higher alcohols, containing 20 to 80% by weight of methanol, 1 to 60% by weight of at least a higher alcohol selected from those containing from 2 to 10 carbon atoms, 1 to 50% by weight of water and 0.1 to 10% by weight of hydrocarbons and/or of oxygen-containing organic compounds different from alcohols, which process comprises the following steps: p0 (a) feeding to a first rectification tower the mixture of methanol and higher alcohols to be dehydrated, a gaseous stream being discharged from the tower head, which contains a portion of the hydrocarbons and/or of the oxygen-containing organic compounds different from the alcohols; from a side point at a level higher than 2/3 of the tower height, a stream containing methanol and possibly ethanol being drawn; and from the tower bottom a stream being obtained with a methanol, and possibly ethanol, and having a content not larger than 10% by weight; (b) separating at least once the stream obtained from the bottom of the first column into two phases, one of which being aqueous, and the other phase being organic; (c) feeding the organic phase to a second tower of azeotropic distillation, using a liquid-vapor and liquid-liquid separation agent; at the bottom an anhydrous stream being obtained, which contains the higher alcohol(s); and from the tower head a stream being obtained, which contains methanol, possibly ethanol and/or propanol, water, and the separation agent used, which is added to the stream obtained from the bottom of the first tower; and (d) feeding the aqueous phase to a third rectification tower; from the bottom a stream being removed which contains water; and overhead a stream being recovered, which is enriched with methanol and higher alcohols, which is recycled by being added to the mixture of methanol and higher alcohols to be dehydrated before being fed to the first rectification tower.</p> |
