Patent ID: 8232442

Claim:
A method for separating aromatic compounds using a simulated moving bed adsorptive chromatography and a crystallization process, comprising: removing a non-aromatic compound from a mixture of aromatic compounds having 7 or less carbon atoms by a sulfolan process; fractionating benzene/toluene; fractionating an aromatic compound which separates aromatic compounds having 8 or more carbon atoms; selectively disproportionating toluene; transalkylating; crystallizing to separate para-xylene; separating para-xylene with a simulated moving bed; and isomerizing xylene; pretreating a xylene mixture with the simulated moving bed between the fractionating the aromatic compound step and the separating the para-xylene with the simulating moving bed step; and an additional isomerizing of xylene to which the xylene mixture from the simulated moving bed xylene mixture pretreating is inputted, wherein a resultant of the sulforan process is inputted to the fractionating of benzene/toluene step, the toluene from the fractionating of benzene/toluene is inputted to the selectively disproportionating of toluene step and the transalkylating step, some of the resultant of the selective disproportionating of toluene step is inputted again to the fractionating of benzene/toluene step, a residual amount of the resultant of the selective disproportionating of toluene step is inputted to an additional benzene/toluene fractionating step, the toluene separated from the additional benzene/toluene fractionating step is inputted to the selective disproportionating of toluene step again, a xylene mixture separated from the additional benezene/toluene fractionating is inputted to the crystallizing for para-xylene separation step, a residual xylene mixture other than the para-xylene is inputted to the simulated moving bed separating of para-xylene step, the xylene mixture from the fractionating the aromatic compound step is inputted to the simulated moving bed separating the para-xylene, and the xylene mixture from the simulated moving bed separating the para-xylene step is inputted to the isomerizing the xylene step.