乙酸甲酯水解催化精馏过程催化剂包内的传质模型(Ⅰ)数学模型

分析了催化精馏过程催化剂包内的传质 ,提出催化剂颗粒的不完全润湿和包内反应物浓度的不均匀是造成催化剂效率下降的原因 .催化剂包总效率因子是表征催化剂不完全润湿程度的表面润湿率 η_s 和表征由于包内反应物浓度的不均造成催化剂效率下降的效率因子 η_c 的乘积 .建立了一个二维传质模型 ,给出了 η_c 的计算式 .结果表明 ,η_c 不仅与反映扩散速率的Thiele模数有关 ,还与反映包内液体轴向流速的参数Ψ或γ有关 .由于催化剂包内存在液体的轴向流动 ,大大减小了扩散传质速率对催化剂包效率因子的影响

MASS TRANSFER MODEL FOR CATALYST CAPSULE IN CATALYTIC DISTILLATION (Ⅰ) MATHEMATICAL MODEL

The mass transfer in catalyst capsule is analysed.It is pointed out that the wetting incompletion of catalyst beads and the concentration gradient within the catalyst capsule reduce catalyst efficiency.The effectiveness factor of catalyst capsule equals to the product of η _s and η _c.The former,the effective wetting rate of catalyst beads,represents the influences of wetting incompletion of catalyst on catalyst efficiency,the latter represents that of concentration gradient.A two- dimensional model is established and an equation to calculate η _c is given.It is indicated that η _c is influenced not only by radial diffusion,but also by axial liquid flow.The influence of diffusion resistance on effectiveness factor is greatly weakened by axial liquid flow.