基于非线性wave理论的内部热耦合精馏过程建模与控制研究

Heat integrated distillation technology is an emerging technology of energy saving in distillation process. Although the heat integrated distillation column (HIDiC) has great energy saving potential, its development and application are limited due to the complex nonlinear characteristics. The mechanism model of HIDiC is too complex, and traditional simplified modeling methods can lead to severe model/plant mismatch. In this study, the nonlinear wave theory will be used to depict the concentration wave profile and velocity, and establish the nonlinear wave model of HIDiC. The wave theory can simplify the model of HIDiC and capture the nonlinear dynamics of the plant as well. Based on the wave model, the state observer will be designed to observe the wave position and parameters online as the bridge between the wave model and the controller. A quality-guaranteed control scheme will be designed to produce high-purity product, and a economy-oriented optimization control problem will be investigated to make sure that the system is both controllable and in the optimal economic condition. In this method, the controllability and the economic optimization are realized simultaneously, in case the traditional optimal system would be hard to control. HIDiC is a frontier in energy-saving distillation, involving both control field and chemical engineering. The entire study will provide a new research strategy for the development of HIDiC and accelerate the industry development of this new technology.

内部热耦合精馏技术是一项节能潜力巨大的新兴精馏节能技术。由于其复杂的非线性特性，使得该技术的发展和应用受到极大的限制。本项目拟采用非线性wave理论的手段，通过对精馏过程中浓度波的波形及波速描述，建立内部热耦合精馏塔的非线性wave模型，在模型简化的同时，保证模型能够准确描述对象的非线性特性，解决机理模型复杂难用、而传统简化建模方法易出现模型失配的问题；设计基于wave模型的状态观测器，实时观测波形位置及波形参数；以wave模型及观测器为基础，首先以产品质量为导向，设计高纯控制方案，然后以经济效益为导向，在确保效益最优的同时，保证系统的可控性，实现控制优化一体化，解决传统方法优化后难以控制以及难以达到实时效益最优的问题。本项目是精馏节能技术的一个前沿，是涉及控制与化学工程的交叉学科，项目的实施为该技术的进一步发展提供新的研究思路，有助于推动内部热耦合精馏技术的工业化进程。

内部热耦合精馏塔具有巨大的节能潜力，然而其复杂的非线性特性使得控制方案的设计较为困难。针对内部热耦合精馏塔非线性强、控制设计难的问题，通过非线性wave理论的手段，研究内部热耦合精馏塔的非线性特性，从wave现象的角度分析内部热耦合精馏塔在操作条件变化或者扰动影响下的变化规律，进而建立相应的非线性wave模型准确的描述研究对象的稳态与动态特性；在wave理论的基础上了设计了在线观测器，用于实时估计无法直接测量的模型参数；在非线性wave模型以及在线观测器的基础上设计了非线性控制方案，解决由于内部热耦合精馏塔的复杂非线性特性带来的控制难题，主要包括两类控制设计方法，一类为以wave模型为基础的基于模型的非线性控制方案，优点是控制精度高，一类为在现有常规控制方案的基础上，通过wave理论在线实时调整设定值，达到减小余差的目的，优点是可实施性强。