Influence of p-Xylene Accumulation on the Operation of Pure Terephthalic Acid Solvent Dehydratic Distillation

A model for solvent dehydratic distillation in pure terephthalic acid process is established and embed in Aspen Plus and the influence of p-xylene mass fraction in reflux on the operation of solvent dehydratic distillation is simulated. By analyzing the residue curves of three key components, it is suggested that when n-butyl acetate is employed as the entrainer, a bypass should be used to control the mass fraction of p-xylene below 0. 15 by draining some solvent from the reflux drum.