SUMMARY
Chemical processing frequently requires vaporizing liquid reagents, mixing, and heterogeneous reaction in the presence of a solid catalyst, followed by product separation. In traditional large scale chemical reactors each process is typically carried out in dedicated components, optimized for their given function, and linked together to form the overall system. Scaled down versions of these large-scale chemical plants have been considered for distributed applications, in particular hydrogen generation from carbohydrate liquid feedstock, but the reactor design based on the individual unit operation approach has been shown to quickly become sub-optimal especially for space-constrained applications. To address this challenge of reactor scale-down, the concept of multifunctional reactors has emerged, in which synergistic combination of different unit operations is explored to achieve improved performance. Among several proposed approaches, combining flash evaporation of finely atomized liquid reagents and catalytic reaction upon contact of the sprayed reagent droplets with the catalyst has been shown to enable a simple, reliable, compact, and scalable reactor platform that offers unique opportunities for greatly improving reactor performance. This proposal focuses on establishing fundamental understanding of the complex interplay between the fuel delivery, evaporation, and reaction in such reactors, resulting in an experimentally-validated methodology for optimal design and operation of a new class of reactors, which we have termed Direct Droplet Impingement Reactors (DDIR). Methanol steam reforming (MSR) will be used as the primary case study for this work since it has significant practical utility as a high energy density source of hydrogen for fuel cells.