Process Synthesis in the Presence of Intricate Chemistry

Ohio State University Research Foundation -Do Not Use, Columbus OH

Investigators

Abstract

In prior grant periods, the PI examined properties of the attainable region for the reactor synthesis problem - i.e. for the problem: given a network of chemical reactions and given feed streams of several reactants, how should those reactants be contacted so as to best meet a specified production objective. He showed that classical reactor types, plug flow reactors (PFRs), continuous flow stirred tank reactors (CSTRs), and differential sidestream reactors (DSRs) play special characteristic roles in shaping the attainable region's outer boundary. He also showed that CSTRs and DSRs that provide access to states at the outermost limits of what is achievable are governed by special design equations. These equations derive in a precise way from the underlying kinetics and can be constructed in great detail even when the attainable region's boundary is unknown. In this new grant period, study of those critical design equations will continue, as will computer "experiments" aimed at evolving the full attainable region. At the same time, there will be a new effort aimed at resolution of certain general reactor-separator questions. Of special interest will be means for assessing sharp kinetic bounds on productivity and selectivity in steady state reactor-separator systems of arbitrary design. Given a kinetics, for example, one might want to know the highest possible steady-state production rate of certain desired species from prescribed feed streams, if there is a specified availability of catalyst, if it is agreed that temperatures and pressures within any reactor component will not exceed levels, and if there are bounds set on the effluent rates of certain toxic side-products. That is one might want to know the highest production rate that can possibly be achieved as one considers all design consistent with the constraints imposed. In broader terms, it is important to know the best that can be hoped for in a stead-state reactor-separator design and to understand when no amount of nonfigurative innovation can produce further gains, so long as certain natural design constraints are respected. Knowledge of this kind provides benchmarks against which existing designs can be measure. The aim is to provide practical tools for designers, managers, and regulators, who faced with a bewildering array of configuration choices, would to well to know, in advance, sharp outer limits on yields and product distributions that can be expected from any constraint-consistent reactor-separator configuration.