METHOD FOR THE SEPARATION OF PARAXYLENE INVOLVING AT LEAST ONE HIGH TEMPERATURE CRYSTALLIZATION STAGE AND AT LEAST ONE CLAY TREATMENT LOCATED UPSTREAM OF THE ADSORPTION AREA.

摘要

Method for the separation of high purity paraxylene from a charge containing xylene isomers comprising the steps of selective adsorption (8) of a paraxylene-rich fraction, at least one stage for crystallizing (5a) said fraction at a high temperature, isomerizing (21) the paraxylene-depleted fraction, recycling the mother liquor (3) to the selective adsorption unit (8) optionally through a clay treatment (26), optionally followed by distillation (28) of the treated effluent. The mother liquor can be injected into a distillation unit (23) after isomerization before being treated in the clay reactor (26). The crystallization stage can include several high temperature stages, wherein the temperature in one of the stages can be comparatively higher or lower than that in the other stage. The method of the invention is suitable for preparing high purity paraxylène for the synthesis of terephtalic acid.