苯乙炔选择性加氢滴流床反应器内的液相轴向返混特性

Axial backmixing of liquid phase in a trickle bed reactor for selective hydrogenation of phenylacetylene

苯乙炔选择性加氢是从裂解汽油C8馏分中回收苯乙烯的关键反应,本文采用滴流床反应器对该反应体系的液相轴向返混行为进行了研究。首先利用脉冲示踪法测得了不同操作条件下的液相停留时间分布密度;然后基于固定床轴向扩散模型,通过有限元正交配置法和Levenberg-Marquardt非线性最小二乘法,计算得到了Péclet数和液相平均停留时间;最后考察了主要操作条件对液相轴向返混的影响。研究结果表明,增大液体流量、气体流量、温度以及压力均可减小液相返混,而增大颗粒粒径会使液相返混加剧。

Recovery of styrene from the C8 fraction of pyrolysis gasoline, a byproduct of steam cracking of naphtha, has been recognized as a very promising approach to meet with increasing demand for styrene, and selective hydrogenation of phenylacetylene is the key reaction during the recovery process. The present study investigated the axial backmixing behaviors of liquid phase in a trickle bed reactor for selective hydrogenation of phenylacetylene. The liquid-phase residence time distribution under various experimental conditions was first measured by using a pulse tracer technique, and then Prclet number and average residence time of liquid phase were determined by the finite element orthogonal collocation method and the Levenberg-Marquardt nonlinear least-squares method. Finally, the effects of operation conditions on axial backmixing of liquid were studied. Liquid backmixing could be reduced by increasing liquid flow rate, gas flow rate, temperature and pressure, but would be exacerbated by increasing particle size.