考虑降液管影响的多元精馏塔动态机理建模 I. 动态机理模型的建立

板式精馏塔的塔板可以分为有降液管和无降液管2种类型，有降液管板式塔中降液管是一个重要的塔内件，合理的降液管既可使液体顺利通过，又可使夹带的气体分离出去，同时防止发生液泛。而目前的精馏塔动态模拟中，其机理模型大都没有考虑降液管的影响，不利于分析蒸馏塔的液相滞留量及故障诊断。在考虑降液管影响的基础上，基于严格理论推导对多元精馏塔进行了动态机理建模，建立了降液管结构和水力学模型，并且考虑降液管部分液相混合的影响，建立了其关联板效率及传质扩散的数学模型。通过理论分析发现，降液管对塔板效率、相平衡常数、蓄液量以及塔板压降等有一定程度的影响，将其影响纳入到多元精馏塔的完整动态机理模型中，通过修正相关模型，更充分地反映了精馏塔的内在机理及其动态特性。

DYNAMIC MECHANISM MODELLING OF MULTICOMPONENT DISTILLATION COLUMN BY CONSIDERING INFLUENCE OF DOWNCOMER I. Building of Dynamic Mechanism Model

The plate distillation column can be classified into two types, one of which is with downcomer and the other without. The downcomer is one of important components in plate distillation columns, so the logical downcomer can make streams pass fluently, the compressibility of gas separated, and prevent the flooding. However mostly the effect of downcomer is not considered in present simulation of plate distillation columns, which makes against the liquid deposition quantities and the fault diagnostics. Based on the consideration of effects of the downcomer and the rigorous theoretical analysis, the dynamic mechanism model of multicomponent distillation column was built. By sufficient considering the liquid mixing phenomena, the structure of downcomer and its hydraulic model were completed. The model of the related efficiency Of plate and mass transfer diffusivity was also established. Through theoretical analysis, a conclusion that some factors such as plate efficiency, phase equilibrium constant, the amount of liquid holdup and pressure drop can be influenced by downcomer was obtained. By modifying relevant models, putting these influences into the integrated dynamic mechanism model, the intrinsic mechanism and dynamic characteristic of multicomponent distillation column can be expressed completely.