Modeling And Optimization Study On PX Oxidation Process

As the most important raw material for the production of polyester, terephthalic acid (TA) is largely produced through the oxidation reaction of p-xylene in acetic acid environment at high-temperature with the cobalt, manganese, and bromine as the catalyst. To further improve the TA production, the modeling and optimization of the industrial reactor were studied in this thesis.The background of the TA production was first introduced in this paper, leading to the research objectives of this thesis. Based on the review of the main and side reaction mechanism of the p-xylene oxidation, a reactor kinetic model comprising both the main and side reactions was proposed. Different from previous researches in lab, the influence of the water in the reactor upon the reaction is also considered in the model to better represent the real production. The kinetic parameters of the model were identified using industrial data, results of which were further compared with the literature reports.With the reactor model developed, simulation was conducted on the p-xylene oxidation process. Consumption of Oa, by-productions of CCh and 4_CBA, average conversion rate and product yield were computed based on collected online data, together with an comparison with the industrial results.To derive the optimal operation conditions for the industry, the influences of the catalyst content, reactor temperature, water composition, and resident time on the production were quantitatively analyzed. Optimization problems for minimizing the consumption of acetic acid and maximizing the throughput of the current equipment were also studied separately. Both the derived results were discussed for the industrial production.As an instruction tool for TA production, the developed reactor model and the proposed optimization technique in this thesis have a powerful potential for the future production enhancement.