Process Simulation of m-Xylene and Ethylbenzene Co-oxidation
1. College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China;
2. Yisheng Dahua Petrochemical Company Limited, Dalian 116000, China
Abstract Co-oxidation of m-xylene (MX) and ethylbenzene (EB) is a new technology to produce isophthalic acid (IA) and benzoic acid (BA). In order to understand the characteristics of MX-EB co-oxidation, the reactor model was established in Aspen Customer Modeler platform and simulated. The hyperbolic kinetic equations of MX-EB co-oxidation were proposed, and mechanism analysis indicated that the introduction of EB would promote the oxidation of MX, which resulted in higher MX conversion, higher IA yield and lower reaction pressure compared with pure component oxidation. Based on this, a co-oxidation reactor model with an annual productivity of 250,000 tons of IA was established. The simulation results showed that the increase of EB content, reaction pressure, catalyst concentration and the decrease of water content would increase the conversion of MX and the yield of IA, and the mass fraction of 3-CBA would decrease, while the concentration of benzoic acid and the consumption of side reactions correspondingly increased. The optimal conditions for MX-EB co-oxidation process are as follows: the mass ratio of EB to MX in raw material is about 0.05, the operating pressure is 1.1 to 1.25 MPa, the catalyst concentration is 200 to 300 mg/kg, and the water content is 8% to 10%.
