Patent ID: 7994378

Claim:
A process of butadiene-1,3 extraction, comprising: feeding a C4 material to a middle portion of a first extractive fractionator, a solvent to a top portion of the first extractive fractionator; wherein, by extractive fractionating, butane and butylene is separated from the top of a column of the first extractive fractionator, butadiene-1,3, trans-butylene-2, cis-butylene-2, butadiene-1,2, butyne-1, vinyl acetylene and solvent are discharged from the bottom to a first stripper and, after separation, butadiene-1,3, trans-butylene-2, cis-butylene-2, butadiene-1,2, butyne-1, vinyl acetylene get out from the top of the first stripper and solvent is discharged from the bottom of the first stripper; pressuring butadiene-1,3, trans-butylene-2, cis-butylene-2, butadiene-1,2, butyne-1, vinyl acetylene discharged from the top of the first stripper, and sending them to the bottom of a second extractive fractionator, and further introducing a solvent from the top of the second extractive fractionator; wherein, by extractive fractionation, crude butadiene comes out from the top of the second extractive fractionator and liquid in the column of the second extractive fractionator is discharged from the bottom of the second extractive fractionator to a butadiene recovery column and, after separation, butadiene-1,3 discharged from the top of the butadiene recovery column is fed to a compressor and liquid in the column gets out from the bottom of the butadiene recovery column to a second stripper, vinyl acetylene offgas is discharged from the top of the second stripper after separation and solvent comes out from the bottom of the column; introducing the crude butadiene from the second extractive fractionator to the top of a first distillation column; wherein, by separation, methyl acetylene offgas is discharged from the top of the first distillation column, the mixture at bottom is sent to the upper portion of a second distillation column for separation and, then, butadiene-1,3 is drawn from the top of the second distillation column and bottom waste containing C 4 and C 5 is discharged to a vaporizer to remove inhibitor, and then enters to the top of the second stripper for diluting vinyl acetylene offgas; partially introducing the butane and butylene separated by the first extractive fractionator to the top of a alkyne fractionator, introducing the vinyl acetylene offgas separated by the second stripper to the bottom of the alkyne fractionator, and introducing the methyl acetylene offgas from the first distillation column to the top of the alkyne fractionator; wherein, by re-separating, butadiene-1,3 is side-drawn from the middle of the alkyne fractionator and returns to the first extractive fractionator through a feed vaporizer, methyl acetylene is vent from the top of the alkyne fractionator and vinyl acetylene is discharged from the bottom of the alkyne fractionator.