Oxidation Of M-Xylene And Primary Product Separation Technology

PIA (Isophthalic Acid), one of the most important raw materials of polyester industry, is produced by the air oxidation of MX (m-Xylene) in acetic acid. This paper mainly studies on the MX catalytic oxidation process and primary product separation technology, and establishes an industrial oxidation dynamic model. Use process simulation software, a practical reactor of liquid-phase catalytic oxidation of m-xylene(MX) to isophthalic acid(PIA), has been evaluated based on the operation results. The thesis mainly includes following three parts:1. Solid-liquid equilibrium of PIA in Acetic Acid+Water Solvent MixturesIn order to make a deeper understanding of the industrial crystallize process, the solid-liquid equilibrium data of isophthalic acid in acetic acid+water solvent mixtures are essential thermodynamic data. The experiments are conducted at different temperatures and solvent compositions covering the industrial operating range. The experimental solubilities are correlated by the λ-h equation and can be used in the synthesis and purification process of isophthalic acid.2. Oxidation reaction kinetics of MX to PIABased on the developed semi-batch experimental technique, the effect of reactant concentration on the oxidation of MX was experimentally examined. The model parameters were re-fitted by coupling the new semi-batch and the previous batch experimental results and can be used to simulate the industrial MX catalytic oxidation process.3. Modeling and analysis for industrial processUsing the solid-liquid equilibrium data in the second chapter and the oxidation reaction kinetics data in the third chapter, a practical reactor of liquid-phase catalytic oxidation of m-xylene (MX) to isophthalic acid (PIA), has been simulated through Aspen Plus. We mainly focus on the oxidation reactor and three-stage crystallizers. The model results showed good agreement with industrial data.