PX氧化反应过程多变量预测控制

精对苯二甲酸(purified terephthalic acid,PTA)是我国最重要的化工原料之一。对二甲苯(p-xylene,PX)氧化反应器是PTA装置的核心运行设备,PX氧化反应是高温高压下的固液相催化反应,其关系到整个装置的产量和消耗。目前,PX氧化反应过程的常规控制虽然可以满足工业装置的生产,但关键产品指标粗对苯二甲酸中对羧基苯甲醛(4-carboxybenzaldehyde,4-CBA)含量和尾气氧浓度波动范围较大,不利于工业装置的进一步优化操作。本文利用FRONT-Suite先进控制软件进行了工业PTA装置PX氧化反应过程的多变量预测控制,稳定优化了关键控制指标反应器尾氧浓度和第一结晶器尾氧浓度以及质量指标4-CBA含量的控制,取得了显著的控制效果。

Multivariable predictive control of p-xylene oxidation reaction process

Purified terephthalic acid is one of the most important chemical raw materials.p-Xylene oxidation is a solid-liquid phased catalytic reaction process under high temperature and high pressure.The reactor is the core unit of purified terephthalic acid plant,which affects the product yield and quality noticeably.Current traditional control strategy can meet the demands of the industrial operation,but the variation of the key quality indexes-the concentration of 4-carboxybenzaldehyde in crude terephthalic acid and the oxygen content in the exhaust are big,which influence the further optimization of the process.In this paper,in order to solve this problem,a multivariable predictive control strategy fulfilled by the FRONT-Suite software is put forward.After the application,the control performance on the 4-carboxybenzaldehyde concentration in crude terephthalic acid and oxygen content in the exhaust of p-xylene oxidation process are improved obviously.