Patent ID: 6696616
Filing Date: 2004-02-24
Classification: C07C

Abstract:
A process for co-production of metaxylene and paraxylene from a hydrocarbon feedstock wherein the process comprises a separation stage of the feedstock in a simulated moving bed in at least one chromatographic column containing a plurality of beds of an adsorbent, interconnected in a loop, said column comprising an injection of the feedstock, which contains at least 6% by weight of ethylbenzene, a draw-off of a first raffinate, a draw-off of a second raffinate comprising metaxylene, an injection of desorbent and a draw-off of an extract comprising paraxylene, whereby the process comprising simultaneous periodic offsetting of injection positions and draw-off position of the extract of a bed in the direction of flow of the main flux that circulates in the column, wherein a first raffinate comprising desorbent, orthoxylene, metaxylene and ethylbenzene is drawn off continuously or intermittently, said second raffinate comprising orthoxylene and metaxylene is drawn off intermittently, and the second raffinate is distilled to recover orthoxylene and metaxylene separately with at least 99% purity, and with yield of metaxylene of more than 10%.