US Patent 10392324 Xylene separation process

A process to separate paraxylene from a mixture of paraxylene, metaxylene, orthoxylene, and ethylbenzene in a commercial simulated moving bed apparatus in a reduced number of beds is provided, allowing an additional separation to be conducted in the remaining beds. This additional separation may separate another xylene isomer, ethylbenzene, or a non-aromatic C8+ hydrocarbon from the raffinate stream produced by the first separation. A PowerFeed process is used to recover paraxylene in a first adsorption zone containing 8-16 beds of a conventional 24-bed simulated moving bed adsorption apparatus, and then a second separation may be conducted in a second adsorption zone containing the remaining beds.