Design of Operating Strategies for Processes with Recycle

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

ABSTRACT PI: Michael F. Doherty and Duncan Mellichamp Institution: University of California Santa Barbara Proposal Number: 0554718 Title: Design of Operating Strategies for Processes with Recycle The PIs plan a research education project to develop hierarchical design methods for rapidly estimating economically optimal operating policies for plants with recycle, and to incorporate the results in a revised edition of James Douglas textbook, Conceptual Design of Chemical Processes. Intellectual Merit The US process industries are under massive pressure to compete in the global marketplace. With such a large asset base, this sector is constantly searching for effective ways to operate these assets more efficiently, e.g., by saving raw materials through improved reaction selectivity, or saving energy by increased reaction conversion, etc. These objectives often conflict, therefore, decentralized or local economic optimization often leads to under performance of the overall manufacturing process. The true overall economic optimum operating policy for a manufacturing process can only be found using plantwide optimization. This leads to a large engineering investment for each individual project, which comes with the risk of finding only marginal improvements for any specific project that did not justify the effort. The PIs approach is to develop mathematically rigorous general rules for classifying rate based processes into equivalence classes that have the same optimal operating strategies. Each individual process can then be classified rapidly according to the rules developed. These rules have the advantage that they are rigorously derived from a mathematical model of the process, and therefore offer a significant improvement over ad hoc heuristics. However, the method of derivation is simple enough that the method and the results can be taught to undergraduates and to plant engineers and operators. Thus, this research fulfils the dual objectives of making the science of process design both more mathematically rigorous and more teachable. This approach also allows for the rapid estimation of the potential economic value of sophisticated process optimization using more rigorous models. Projects can be ranked according to their payback, thereby justifying further engineering investment in more detailed optimization and economic evaluation using advanced methods. . Broader Impact The results of this work may help the chemical process industries by designing more commercially profitable manufacturing facilities while also having a benefit on the environment by saving energy. The revised textbook will help educate undergraduates. Graduate research assistants will also be educated in this important area, and they will help transfer the technology to industry when they graduate.