规整填料塔多元蒸馏过程混合型模型的模拟

填料塔精馏过程的模拟设计大多采用平衡级模型,但由于单一板效率值的难以确定,很多场合模拟很不成功;而新提出的非平衡级模型认为塔内传质传热均处于非平衡状态,由于方程数和经验性参数多,模型求解非常困难。文章针对规整填料的特点,建立了规整填料塔蒸馏过程的一种混合型模型,模型的主要特征是认为气液二相传质处于不平衡状态,而传热处于平衡状态。模型建立在实际填料基础上,既舍去传统的平衡级模型不确定性,又省略了非平衡级模型中复杂的经验性传热系数和液相传质系数的计算。模型计算值和实验值符合较好,也证实混合型模型既反映实际,又使模型求解变得相对容易。

A hybrid simulation model for multicomponent distillation in structured packing column

For modeling and designing distillation process in packed columns,conventional equilibrium-stage model is mainly used.But this approach is unsuccessful in many cases due to difficulty in determining the unique plate-efficiency value.Newly developed non-equilibrium stage model deemed as "mass transfer and heat transfer both in non equilibrium state"sounds more reasonable but leads to difficulty in model solving because of introducing more equations and more empirical computations.Aiming at the feature of structured packing,a hybrid simulation model for multicomponent distillation in structured packing columns was developed.A key feature of this model was deemed as "mass transfer in non equilibrium state while heat transfer in thermodynamic equilibrium state".Under proper assumption that mass transfer resistance is only in vapor phase,this approach not only avoids the uncertainty associated with equilibrium stage model,but also omits the empirical computations of heat transfer coefficients and liquid mass transfer coefficients.The comparison of the model prediction and experimental observation shows a good agreement,which proves that the hybrid model is not only more reasonable in state but also easier in model solving.