Abstract:

This article focuses on the study of the promoting influence of CO₂ on the liquid phase oxidation of p-xylene (PX) under industrial reaction conditions. Using a continuous experimental setup, the influences of gas-phase CO₂ content and temperature on PX oxidation were investigated, and the processes were simulated by means of reactor modeling. It was found that CO₂ could significantly increase the PX conversion and the yield of the primary product in the reactor outlet and reduce the content of the main impurities in liquid phase, when the CO₂ concentration is between 40%—60%. When temperatures are higher than 192℃, the effect of temperature on the reactor outlet index is noticeably higher than that at lower temperatures. The mixed-flow reactor model successfully predicted the main index changes of reactor outlet with the residence time at different CO₂ contents and temperatures, such as the PX conversion, yield of the primary product, and the contents of major impurities in the liquid phase. Hopefully, the results of this work could provide new ideas for enhancing efficiency and energy saving of current industrial PX oxidation processes.

Key words: carbon dioxide promoting oxidation, p-xylene, continuous experiment, simulation

摘要：

利用连续实验装置考察了气相CO₂浓度和反应温度对PX氧化反应的影响,并通过反应器建模对连续实验过程进行了模拟计算。研究结果表明,当气相CO₂浓度介于40%～60%时,CO₂能显著提高反应器出口PX转化率以及主产物收率,并且可以降低液相中主要杂质的含量;温度高于192℃后对反应器出口指标的影响比低温时明显。本文建立的全混流反应器模型能够预测气相CO₂含量以及温度等不同反应条件下氧化反应器出口的PX转化率、主产物收率以及液相主要杂质随停留时间的变化。相关研究结果可为当前工业PX氧化过程效率提高以及节能降耗提供新的思路。

关键词: 连续实验, 模拟计算, 二氧化碳, 对二甲苯