Collaborative Research: Design and Model-based Control of Nonlinear Chemical Processes

摘要：Masoud Soroush机构：德雷克塞尔大学（Drexel University）为了获得更大的盈利能力，过程设计师一直在复杂非线性领域进行设计，而过程控制器在这些领域面临着严峻的挑战。稳态多重性、极限环、混沌和参数敏感性是非线性的表现。除了非线性之外，还有许多工艺设计具有不稳定和/或非最小相位稳态。在许多情况下，在不稳定的稳定状态下，或者在不稳定的稳定状态附近的稳定状态下，通常涉及非最小相位行为（逆响应），操作更有利可图。可以表现出这种行为的工艺设计的例子有化学反应器、发酵反应器、流化催化裂化装置、反应器-分离器-回收装置、共沸蒸馏塔和再锅炉。与稳定和最小相位稳态的过程相比，具有这种设计的过程更具有挑战性。这个宾夕法尼亚大学和德雷塞尔大学的联合研究项目旨在解决不稳定和/或非最小相稳态过程的更有效和更容易的操作。它研究过程中设计和控制之间的相互作用，以及开发过程设计使过程控制更容易的策略。现有的化学和生化过程的不稳定和/或非最小相稳态的设计将被研究，以确定设计特征，导致这种过程的行为。如果可能的话，将为这些工艺开发可替代的新工艺设计，以便保持相同水平的盈利能力，但消除不稳定性和非最小阶段行为。对于无法找到所需替代设计的过程，将开发新的微分几何，基于模型的控制律，适用于一般非线性过程，无论是最小相位还是非最小相位。最初，控制律将发展为一般的，非线性的，连续时间过程没有死时间或输入饱和约束。随后，后两个复杂问题将得到解决，方法将扩展到多输入多输出（MINO）系统，并对化学、石化和生化过程进行测试。一个原型符号操作软件，给定一个过程模型，将自动生成微分几何控制规律，以简化其工业实施和测试。

ABSTRACTPI: Masoud Soroush Institution: Drexel University Proposal Number: 0101133To achieve greater profitability, process designers have been creating design in regions involving complex nonlinearity where process controllers continue to face stiff challenges. Steady state multiplicity, limit cycles, chaos, and parametric sensitivity are manifestations of the nonlinearity. In addition to the nonlinearity, there are many process designs that have unstable and/or non-minimum-phase steady states. In many cases, operation is more profitable at an unstable steady state, or at a stable steady state in the close proximity of an unstable steady state, often involving non-minimum-phase behavior (inverse response). Examples of process designs that can show such behavior are chemical reactors, fermentation reactors, fluidized catalytic crackers, reactor-separator-recycle plants, azeotropic distillation towers, and reboilers. Processes with such designs are known to be more challenging to control than processes with stable and minimum-phase steady states.This University of Pennsylvania-Drexel University joint research project is aimed at addressing more efficient and easier operation of processes with unstable and/or non-minimum-phase steady states. It is a study of the interactions between design and control in the processes, and strategies to develop process designs that make control of the processes easier. The designs of existing chemical and biochemical processes with unstable and/or non-minimum phase steady states will be studied to identify the design features that give rise to such process behavior. Alternative new process designs, if possible, will then be developed for the processes such that the same level of profitability is maintained but the instability and non-minimum-phase behavior are eliminated. For processes for which such desired alternative designs cannot be found, new differential-geometric, model-based control laws will be developed that are applicable to general nonlinear processes, whether minimum-phase or non-minimum-phase. Initially, control laws will be developed for general, nonlinear, continuous-time processes without deadtimes or input-saturation constraints. Subsequently, the latter two complications will be addressed, and the methods will be extended to multi-input-multi-output (MINO) systems and tested for chemical, petrochemical, and biochemical processes. A prototype symbolic-manipulation software that, given a process model, automatically generates differential geometric control laws will be developed to simplify their industrial implementation and testing.