间歇精馏模型说明书

间歇精馏模型BatchFrac事例用于模拟丙酮和水说明书

(1) BatchFrac模型简介

BatchFrac 是一个用于间歇蒸馏的单元操作模型，它是模拟多级间歇蒸馏塔的一个严格的模型。BatchFrac 用一种十分有效的算法来求解非稳态的描述间歇蒸馏过程的热平衡方程和物料平衡方程，在每个平衡级上都提供了严格的热平衡物料平衡和相平衡关系。BatchFrac 能够处理各种间歇蒸馏问题包括以下系统：● 窄沸程

● 宽沸程

● 高度非理想系统

● 三相系统

● 反应系统

BatchFrac能够检测冷凝器中游离水的存在或者是塔中任意位置的第二液相的存在，BatchFrac在模拟级间倾析器时具有很大的灵活性，BatchFrac可以模拟带有平衡或速度控制的反应的间歇蒸馏塔这些反应可以发生在任意一个平衡级上包括再沸器和冷凝器。

BatchFrac模型假定：

● 使用平衡级但你可以规定汽化率

● 有连续的液体滞留且没有气体滞留

● 不模拟塔水力学

(2) BatchFrac模型输入规定

BatchFrac塔板是从上往下计算的，起始于冷凝器。其精馏过程是一个连串的顺序操作过程，BatchFra的第一个操作步骤是进行全回流运算。

BatchFra有两种形式的数据输入规定：

● Column setup(塔设置)

● Column operation(塔操作)

①Column setup(塔设置)

Setup specifications define the column you are modeling, but they do not define its operation. These specifications include:Number of stages、Column holdup profile、Pressure profile、Initial charge、Final product specifications

You can choose to specify these on the BatchFrac Setup Form:

Interstage heaters and coolers

Heat-loss profile

Three-phase distillation and decanters

Vaporization efficiency

Reactions and property options for column segments

All Column Setup specifications, except for the initial feed and final charge, can be overridden during any subsequent operation step. You can also request the simulation to record result profiles other than the default at the Setup level. You can set specific block options, algorithm convergence parameters, and diagnostic levels. You can specify user subroutines for pressure profile calculation and reboiler heat

duty calculation.

You must specify On this sheet

Total number of stages Setup Configuration

Column holdup profile Setup Holdup

Column pressure profile Setup Pressure

Initital charge stream and final outlet streams Setup Charge/Products

②Column operation(塔操作)

Column operation specifications define the operating conditions of the column during an operation step. They include operating specifications such as reflux ratio and distillate rate, and stop-criterion information. You can choose to specify intermediate charges to the reboiler, continuous feeds, sidedraws, and intermediate dumps at the operation step level. You can override some global specifications at the operation step level. Other specifications depend on the column configuration and algorithm being used.

(3) BatchFrac事例

丙酮与水的分离。

进料：25℃，1.051atm，3200kg/h，组成：丙酮0.99，水0.01

由于是间歇精馏，因此釜液的进料量为一定量，等于total flow（3200kg/h）乘以

进料时间（在BachFra c 中BLOCK1→setup →Charge/Product →Initial Charge 中的Feed Time 规定进料时间）

①物流1输入如下图所示

②BachFra c 模块设置如下图所示