| 摘要 |
<p>The invention relates to a process and an apparatus for separating degassed and dewatered thermally sensitive multi-component mixtures in vacuum. The aim and object of the invention are to ensure the attainment of high yields of a colour-stable main fraction of good quality with complete separation of residue and first runnings and with low consumption of energy and low expenditure in terms of apparatus. The object is achieved according to the invention in that the multi-component mixture is divided into two fractions at 300 to 500 Pa, from which, at 100-200 Pa, by evaporation and condensation and circulation of the vapours containing non-condensing first runnings, a first main fraction, the residue, a second main fraction and, if present in the multi-component mixture, first runnings are successively condensed. The separation of this multi-component mixture is carried out in only one column which is furnished with external and internal heat exchanger surfaces and is subdivided by chambers into a plurality of functional spaces. The vapour velocities in counter-current flow are 30 to 50 m/s. The first runnings fractions can be removed to a level lower than 0.1%, for which purpose only small reflux rates are required.</p> |
