| 摘要 |
The invention relates to a method for providing a vaporous purified crude C4 fraction as a feed stream for an extractive distillation process using a selective solvent, having the method steps of 1) separating the C3-hydrocarbons, 2) separating the C4-oligomers and -polymers as well as the C5+-hydrocarbons up to the respective residual content specified above for the vaporous purified crude C4 fraction, and 3) evaporating the liquid crude C4 fraction. The method is characterized in that all the method steps 1), 2), and 3) are carried out in a single distillation column which is fed the liquid crude C4 fraction in the upper third of the column thereby forming a rectifying section and a stripping section and from which a head stream containing the C3-hydrocarbons and a bottom stream containing the C4-oligomers and -polymers as well as the C5+-hydrocarbons are drawn, and the vaporous purified crude C4 fraction is drawn from the stripping section as a side stream. |
