Impact of catalyst, bubble and droplet properties on the selectivity of fast multiphase reactions

Many industrial processes in chemical, petrochemical, and pharmaceutical manufacturing involve reactive mass transfer across a fluid interface. Understanding the impact of reactive mass transfer and local flow in these systems is crucial for maximizing reaction selectivity and minimizing byproduct formation. These byproducts can be detrimental to the environment and costly because additional manufacturing steps are often needed to separate, dispose, or rework the byproducts.; The goal of this research is to improve our understanding of how mixing impacts fast multiphase reactions. A reaction is considered fast in a multiphase system if the reaction occurs close to the liquid-liquid or gas-liquid interface, i.e., near the roof or wake of the bubble or droplet. The dynamics of the wake determine the mixing and transport of reactants. If the reaction is heterogeneously catalyzed, then additional information regarding the dispersion of catalyst particles is needed to determine the reaction products. Previous work in homogeneous reaction systems has extensively demonstrated that the final product composition and yield are strongly influenced by the contacting scheme, mixing, and reactor hydrodynamics. Unfortunately, our understanding of fast multiphase reaction systems is still limited.; Through a comprehensive theoretical study, this research identified the relationship between bubble and particle properties and the selectivity of fast heterogeneously catalyzed gas-liquid reactions. In these types of reactions, the selectivity of the reaction network becomes dependent upon the mixing and segregation of the catalyst particles, as well as the mixing and segregation of the reactants. Two industrially relevant reaction systems were used to demonstrate the selectivity dependence on the operating conditions of the bubble column and the catalyst particle size. Additionally, a fast liquid-liquid reaction was used to demonstrate the relationship of droplet properties on the selectivity. This demonstration was possible since the mixing in these experiments was created by the motion of the droplet falling through a stagnant liquid. By understanding that bubble or droplet dynamics impact the yield and selectivity of fast reactions, the formation of byproducts can be minimized by optimizing operating parameters. These systems can then be optimized to obtain the maximum reaction yield for a specified selectivity.