Beyond Yield: Assessing Reaction System Performance using Economics

Abstract

Early stage exploration of reaction systems, including catalyst selection, operating conditions� specifications, reactor design, and optimization, is critical in the engineering field. It is general practice in the reaction engineering field to explore systems against certain performance metrics, of which yield is one of the most commonly utilized objectives. While the yield provides a quantitative measure of how efficiently reactants are converted into target product(s), its definition is ambiguous, particularly in the presence of side/ incomplete reactions, and multiple products. Most of the yield definitions focus on a specific target product; however, conditions within the reactor search space that provide a maximum yield for one product may not be the same as those for another. Moreover, the presence of other undesired products that are not considered may reduce the overall efficiency of the system. This necessitates the utilization of a more holistic metric that encompasses the value of all the generated products. Attempts to address this consider lumping components into a total yield metric. However, this assumes equal weights on all components without adequately capturing their individual significance on the actual performance. This study proposes the utilization of an �economic-value yield� objective that captures all the products� value by using the market price as a weight factor. The traditional yield metric for the various products is contrasted against the economic one to highlight its ability of providing insight into regions within the reactor search space that are associated with high-value products that are otherwise not observed in the conventional definition. This is illustrated with a case study utilizing propane as a feedstock in the novel piston reactor technology.