间歇精馏塔启动过程的模型化

引　言在以往的研究中 ,间歇精馏塔的模型大部分建立在平衡模型的基础上1] ,系统初值的选取基于伪热初始状态 ,即每层塔板上有足够的积液量 ,塔板温度在泡点温度以上的汽液平衡状态 .多数间歇精馏过程的仿真模拟软件中使用伪热状态作为初始状态2 ] ,例如 ,ＨＹＳＹＳ Ｒ○ (Ｈｙｐｒｏｔｅｃｈ )、ＢＡＴＣＨＦＲＡＣＴＭ (Ａｓｐｅｎｔｅｃｈ )和ＣＣ -ＢＡＴＣＨ Ｒ○(ＣＨＥＭＣＡＤ) .它们都是通过稳态和平衡计算为微分代数方程组提供了满足一致性要求的初始值 .间歇精馏过程的一个特点就是精馏塔频繁地从冷状态启动 ,初始状态会因再…

MODELING OF BATCH DISTILLATION STARTING FROM COLD STATE

Modeling of batch distillation has been mostly based on equilibrium model in previous studies.It leads to a large-scale differential algebraic equations (DAEs) system.Due to its dynamic nature,initialization of the system has been a problem.Batch distillation columns are frequently started up with different initial reboiler charges.A model to express startup behavior of batch columns starting from an empty cold state is proposed to handle this issue.Each tray will be described from a non-equilibrium phase in which only mass and energy transfer are taking place to an equilibrium phase in which the vapor-liquid equilibrium is reached.The switching point between these two phases is decided by the relationship of bubble-point temperature at the operating pressure.The liquid holdup of each tray is related to the geometry of the trays.The model is verified through experiment on a pilot batch plant with a bubble-cap tray column to separate a methanol-water mixture.