METHOD FOR OBTAINING A CONJUGATED DIOLEFIN AND / OR OLEFIN FROM A C (DOWN ARROW) 4 (DOWN ARROW) - OR C (DOWN ARROW) 5 (DOWN ARROW) HYDROCARBON MIXTURE

摘要

1. A process for recovering a conjugated diolefin and/or olefin or olefin mixture from a C4 - or C5 -hydrocarbon mixture which contains the conjugated diolefin and/or the olefin or olefins, hydrocarbons which are more sparingly soluble in the selective solvent than the said diolefin and/or the olefin or olefins, and hydrocarbons which are more readily soluble in the said solvent than the said diolefin and/or the olefin or olefins, the C4 - or C5 -hydrocarbon mixture being separated, by means of extractive distillation, into a distillate containing the more sparingly soluble hydrocarbons, a product stream containing the conjugated diolefin and/or the olefin or olefin mixture, and a stream containing the more readily soluble hydrocarbons, wherein the extractive distillation is carried out using - a distillate take-off zone (separation zone C), - a feed zone for the starting C4 - or C5 -hydrocarbon mixture (separation zone A), - a product take-off zone for the product stream (separation zone B) and - a stripping zone in which the selective solvent is recovered and from which the stream containing the more readily soluble hydrocarbons is taken off (separation zone D), and (a) the starting C4 - or C5 -hydrocarbon mixture is fed to separation zone A, (b) the selective solvent to be fed to the extractive distillation is introduced into the upper part of separation zone C, (c) some of the laden selective solvent obtained in the lower part of separation zone C is fed to the upper part of separation zone A and the remainder is fed to the upper part of separation zone B, (d) the laden selective solvent obtained in the lower part of separation zone A, and that obtained in the lower part of separation zone B, are fed to separation zone D, from which the stream containing the more readily soluble hydrocarbons, and a stream of the selective solvent which has been partially or completely freed from the hydrocarbons, are removed, (e) a product stream containing the conjugated diolefin and/or the olefin or olefin mixture is taken off from separation zone B, and (f) the distillate is removed from separation zone C.