对苯二甲酸的加氢精制过程Ⅱ.不同粒度催化剂上4-CBA表观加氢动力学

Hydropurification of Terephthalic Acid over Pd/AC Ⅱ.Apparent Kinetics of 4-CBA Hydrogenation on Catalysts of Different Sizes

摘要: 对Pd/AC催化剂上对苯二甲酸(TA)加氢精制过程中的对羧基苯甲醛(4-CBA)加氢反应进行了研究。考察了氢分压、反应温度、催化剂颗粒大小对4-CBA消逝速率的影响,结果表明:在高于0.35 M Pa时,氢分压对4-CBA加氢反应速率的影响很小,而温度和催化剂粒度大小对加氢反应的影响显著。同时,工业条件下的TA加氢精制过程存在着严重的内外扩散。采用幂函数动力学模型方程利用M atlab拟合得到了不同粒度催化剂上的表观动力学方程。

Abstract: A study is carried out on purification of crude terephthalic acid using a batch autoclave.The dependence of 4-CBA hydrogenation rate on reaction conditions such as hydrogen atmosphere,agitation rate,temperature and catalyst particle size is carefully investigated.Results indicate that the hydrogen(atmosphere) has little effect on hydrogenation reaction within the industrially-acknowledged boundary.(However,) the hydrogenation rate is sensitive to temperature and catalyst particle size,implying strong diffusion resistance in the hydropurification process.As a result,kinetic equations for hydrogenation of(4CBA)(under) different conditions are obtained from the experimental data.The activation energy as well as the(reaction) order are estimated based on the power-law kinetics under various conditions.