Global Optimization of Process Models Incorporating Detailed Chemical Kinetics Mechanisms

点击翻译按钮获取中文摘要

Abstract - Carr 9504827 Chemical engineering is concerned with the design, construction, operation, and control of complex processes. The associated system geometry can be complex because the chemical reactions involved take place within a time- and space-varying environment and/or the reactions themselves may be very complex, entailing hundreds of species participating in a network of many more reactions. Optimization of the system or process may require a global search through a parameter space of high dimension, each step of the search requiring integration of the chemical-kinetic equations and the equations of mass and heat transport with time-dependent boundary conditions and spatial inhomogeneity. Large demands are thus made for quantitative information on reactions rates and for computing power. This research will address the problem by proceeding along two fronts: (1) the development of numerical analytic and visualization tools, and (2) the application of the available tools to kinetic and reactor models of varying complexity. The PIs plan to develop a data parallel code for the local optimization of large sets of ordinary differential equations/differential algebraic equations (ODEs/DAEs) on the CM-5 (connection machine) at the Minnesota Supercomputer Institute. An augmented Lagrangian code has been developed and another code incorporating successive quadratic programming will be written. These codes will be tailored for simultaneous optimization and solution of the underlying ODEs/DAEs via orthogonal collocation and used to study larger and more detailed kinetic models for methane oxidation. One dimensional transport and simple turbulence models may also be included. The next stage of development will be to construct a code for Bayesian stopping rules in conjunction with multistart random search. The construction of a small step methane oxidation kinetic mechanism will follow. It will be optimized to match the output of the full kinetic scheme in a simple reactor in t he vicinity of the global optimum of the latter.