融合CFD与非平衡模拟的复杂精馏过程多尺度模型

The green and sustainable chemical engineering in the 21 century is known complex and characterized with multiscale natures. Hence, an integrated multiscale modeling will be the future direction for chemical process simulations. However, it is still difficult to combine directly molecular simulation with process simulation due to the limited computing power. This research focuses on mesoscopic and macroscopic scale to establish a multiscale modeling approach with combined mesoscopic CFD (computational fluid dynamics) simulation and macroscopic process simulation. Under the proposed multiscale framework, a "mesoscopic-macroscopic" scale oriented general modeling strategy called DCIMM (decomposition, coordination, and integration for multiscale model) will be explored for complex chemical processes. As application examples, the complex distillations such as multicomponent distillation, heterogeneous distillation and reactive distillation will be studied in this research. The mesoscopic CFD model and the macroscopic NEQ (nonequilibrium) model will be built up and can exchange parameters through middleware integration. In the DCIMM, the CFD model simulates the mesoscopic fluid dynamics and computes out the transfer parameters, which are needed in the NEQ distillation simulations but known difficult to be derived. Hence, the DCIMM can achieve all mechanism based simulation in the "mesoscopic-macroscopic" scales. The contributions of the research can build up a bridge between mesoscopic and macroscopic, and help to catch up the mesoscopic essential factors which affect the mass transfer and separation efficiency, and establish a solid model background for optimized design and control of complex chemical processes.

二十一世纪的绿色化工和可持续化工呈现多尺度的复杂特性。因此多尺度集成模型将成为未来化工过程模拟的发展方向。然而受计算能力的限制，当前要实现从分子模拟到过程模拟的直接集成还存在困难。本项目从介观尺度和宏观尺度着手，致力于建立"融合介观CFD和宏观过程模拟的多尺度模型"- - 在多尺度系统的理论框架下，探索面向"宏观-介观"尺度的化工过程复杂系统"多尺度分解、协调与综合"的一般性理论和集成化建模方法；同时，以多组份精馏、非均相精馏、反应精馏等复杂精馏过程为应用研究对象，分别建立介观CFD模型和宏观非平衡模型，并通过中间件实现集成和参数交换。在该模型下，利用CFD模型仿真介观流体特性并计算介观传递参数，克服当前精馏非平衡模拟的一个主要困难，实现融合"宏观-介观"尺度的全机理仿真。研究成果搭建宏观和介观的桥梁，有助于抓住影响传质和分离效率的介观本质，为优化设计和控制奠定模型基础。

本项目从介观尺度和宏观尺度着手，建立了“融合介观CFD和宏观过程模拟的多尺度模型”——在多尺度系统的理论框架下，探索面向“宏观-介观”尺度的化工过程复杂系统“多尺度分解和连接”的一般性理论和集成化建模方法；同时，以多组份精馏、非均相精馏等复杂精馏过程为应用研究对象，建立了基于实验环境和基于Labview的自动化测试系统，在气液液三相多流态辨识的基础上建立介观CFD模型库。在该模型下，利用CFD模型仿真介观流体特性并计算介观传递参数，克服当前精馏非平衡模拟的一个主要困难，实现融合“宏观-介观”尺度的全机理仿真。同时，针对精馏过程多尺度建模研究解决了参数辨识的关键技术，提出了基于EWMA滤波的闭环辨识方法。此外，通过国内外合作研究，建立了精馏多尺度模型的实验数据库和并确立了精馏多尺度建模所需的传质参数关联公式体系，为优化设计和控制奠定模型基础。