| 摘要 |
Separation of a 4 carbon (C) hydrocarbon mixture (I) involves extractive distillation with N-methyl-2-pyrrolidinone (NMP) into 1,3-butadiene, butene and butane fractions and fraction(s) containing other 4 C hydrocarbons (II). The stages used comprise; (1) complete absorption of 1,3-butadiene and (II) from gaseous (I) with NMP and separating the solution (III) from a gas stream (IV) of unabsorbed butenes and butanes; (2) desorption of butadiene from (III) and separation from the liquid phase (V) containing most of (II); (3) desorption of (II) in one or more fractions from (V); (4) complete absorption of butenes in (IV) in NMP from stage (3) and separating the unabsorbed butanes; (5) desorbing the butenes from the solution; and (6) recycling the NMP free from stage (5) to one of the extraction zones. Each desorption zone operates at a lower pressure and/or higher temperature than the immediately preceding absorption or desorption zone. Separation of a 4 carbon (C) hydrocarbon mixture (I) involves extractive distillation with N-methyl-2-pyrrolidinone (NMP) into >= 4 fractions comprising (a) a 1,3-butadiene fraction, (b) a butene fraction, (c) a butane fraction and (d) fraction(s) containing other 4 C hydrocarbons (II). The stages used comprise; (1) complete absorption of 1,3-butadiene and (II) from gaseous (I) with NMP and separating the solution (III) from a gas stream (IV) of unabsorbed butenes and butanes; (2) desorption of butadiene from (III) and separation from the liquid phase (V) containing most of (II); (3) desorption of (II) in one or more fractions from (V) and separation from NMP free from 4 C hydrocarbons; (4) complete absorption of butenes in (IV) in NMP from stage (3) and separating the unabsorbed butanes and solution (VI); (5) desorbing the butenes from (VI) and separation from NMP free from 4 C hydrocarbons; and (6) recycling the NMP from stage (5) to one of the extraction zones. Each desorption zone operates at a lower pressure and/or higher temperature than the immediately preceding absorption or desorption zone.
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