Device for the separation of paraxylene from the aromatic hydrocarbon cut by adsorption, comprises ordinary elementary zones in series functioning as a closed loop, and a specific elementary zone

摘要

The device for the separation of paraxylene from the aromatic hydrocarbon cut with 8 carbon atoms by adsorption, comprises ordinary elementary zones Z iin series functioning as a closed loop, and a specific elementary zone (Z o). Each ordinary elementary zone comprises single solid absorbent bed L ihaving a volume VA i, a circulation volume, a volume VA and a non-selective empty volume V iand V between two successive points of sequential injection of filler or eluent or sequential extraction of the extract or raffinate. The specific elementary zone is different from the ordinary zone. The device for the separation of paraxylene from the aromatic hydrocarbon cut with 8 carbon atoms by adsorption, comprises ordinary elementary zones Z iin series functioning as a closed loop, and a specific elementary zone (Z o). Each ordinary elementary zone comprises single solid absorbent bed L ihaving a volume VA i, a circulation volume, a volume VA and a non-selective empty volume V iand V between two successive points of sequential injection of filler or eluent or sequential extraction of the extract or raffinate. The specific elementary zone is different from the ordinary zone, comprises a non-selective empty volume V ohigher than V and a solid single bed L oof volume VA olower than VA. Same solid absorbent units S are used for the different ordinary zones. Solid absorbent unit S ois a mixture of two solid absorbents S 1and S 2of different volumic absorption capacity such as C 1and C 2, where C 1greater than C 2, and is used for the specific elementary zone. The voluminal adsorption capacity Co of the solid So is higher than that of the solid S, so that the total adsorption capacity CoVAo of the particular elementary zone Zo is close to the total adsorption capacity CVA of each ordinary elementary zone than the calculated total adsorption capacity. The difference in the total adsorption capacity of the specific elementary zone Zo is reduced to 70% compared to the total adsorption capacity of the ordinary elementary zone, as given in the specification. The solid absorbent S 1possesses high volumic absorption capacity. The percentage of S 1in each of the ordinary elementary zone is zero or lower than the percentage of S 1in the bed L o. The solid absorbent unit in each of the ordinary elementary zone is constituted by a homogenous solid absorbent unit S of volumic absorption capacity C. The solid absorbent unit S ocomprises another absorbent unit S 1of volumic absorption capacity C 1, which is greater than C. An independent claim is included for a process for loading a simulated movable bed in a separation device by absorption.