间歇精馏塔启动过程的流程模拟及混杂性分析

Complex hybrid model for startup of batch distillation

间歇精馏塔启动过程的流程模拟是通过一个动态混杂系统模型来描述的.通过分析模型中的混杂性问题,对非连续性特性进行了分类:即与启动过程状态转换有关的模型结构的不连续性;与物理过程有关的塔板动力学方程的切换.并针对动态模型所涉及的变量初始值问题,给出了不同类型变量的初值选取方法.最后通过基于gPROMS计算平台的仿真结果和实验结果的比较,验证了模型求解的有效性.

A property of batch distillation startup process is that a batch column will be frequently started up from a cold state. The amount , composition as well as the kind of components in the initial charge may be varia ble from batch to batch. For one batch, the transients/transitions or (thermodyn amic) phase changes are very likely to occur. So batch distillation startup proc ess is a complex hybrid (discrete/continuous) dynamic system. The model for star tup operation appears discontinuous between nonequilibrium phase and equilibrium phase. There are two kinds of discontinuous mode in simulation model: (1) s truc ture discontinuous mode of the model, (2) equilibrium and hydraulic equations sw itching. In this paper, some trivial equations are introduced to solve the first problem. The second problem was related to with the variables' initial value. T here ar e three types of variables: state variables, hydraulic variables and attendant v ariables, and different methods are used to describe the variabl es' initial value. T he software gPROMS was used for solving the equations due to its ability of deal ing with discontinuities of variables. The model was verified through the experi ment.