碱减量废水残渣甲酯化反应动力学研究

为实现碱减量废水残渣有效利用,对碱减量废水残渣甲酯化反应条件与反应动力学规律进行了系统考察。论文首先考虑洗涤干燥等预处理方法对碱减量废水残渣组成的影响,然后通过改变醇酸比、初始水分含量及反应温度条件,进行了碱减量废水残渣甲酯化反应动力学实验研究。结果表明,预处理可有效去除残渣中的无机盐杂质提高对苯二甲酸纯度,但预处理会明显降低后续残渣甲酯化产物对苯二甲酸二甲酯(DMT)的收率以及对苯二甲酸(TA)甲酯化反应的转化。TA甲酯化两步反应均对温度敏感,采用典型的可逆平衡反应模型对实验数据进行拟合,得到动力学模型参数,并在此基础上对动力学模型进行检验,结果表明所建立的动力学模型是可靠的,能很好的预测各组分的浓度。研究所得可为碱减量废水残渣甲酯化工艺放大与设计提供依据。

Study on Kinetics of Methyl Esterification of Alkali Weight-Reduction Wastewater Residue

To achieve the effective utilization of alkali weight-reduction wastewater residue,the methyl esterification reaction conditions and the reaction kinetics were systematically investigated.The kinetics of methyl esterification reaction of alkali weight reduction wastewater residue was studied by firstly considering the effect of pretreatment such as washing and drying on the composition on the wastewater residue and followed by changing the alcohol-to-acid ratio,initial moisture content and reaction temperature.The results showed that the pretreatment could on one hand effectively remove the inorganic salt impurities in the residue to improve the purity of terephthalic acid (TA),but on the other hand it could significantly reduce the yield of dimethyl terephthalate (DMT) and the conversion of terephthalic acid (TA) methylation reaction.Two steps TA methyl esterification reactions were both temperature sensitive.The typical reversible equilibrium reaction model was used to fit the experimental data to obtain the kinetic model parameters,and on this basis,the kinetic model was tested.The results showed that the established kinetic model was reliable and can well predict the concentration of each component.The study can provide the basis for further scale-up and design of methyl esterification process for alkali weight reduction wastewater residue.