| 摘要 |
<p>The invention relates to a method for the separation and purification of an aqueous mixture of main components, namely acetic acid and formic acid and non-volatiles by extraction, using a solvent in a circulatory system characterized in that the raffinate stream is mixed with the larger proportion of water from a solvent stripper column (11) for the removal of water. The extraction stream is introduced into a solvent distillation column (8), from which in a first step involving the use of a mixture (A) containing a large proportion of the solvent is separated out via a header and a mixture (B) consisting of formic acid, water and solvent is separated out via a side-arm and a mixture (C) consisting of acetic acid and non-volatiles is also separated out. A mixture (B) is introduced into a formic acid distillation column (4) for further processing, and a mixture (C) is introduced into an acetic acid distillation column (5), and purified acetic acid is subsequently isolated in the acetic acid distillation column (5) from the header. Pure formic acid is isolated at the settling basin of the formic acid distillation column (4) and a mixture of solvent and water is extracted via the header which is then reintroduced into the extractor (7) after the water component has been separated off from the mixture (A).</p> |
