Title: Polymorph Selection in Continuous, Reactive, Rate-based, Precipitation Systems
Many materials are capable of organizing into multiple distinct solid phases, each exhibiting a unique set of material properties (e.g., mechanical, optical, electronic, catalytic, etc.). This material property diversity implies that a specific solid form or structure is typically preferred for a specific application. Thus, directing and controlling solid form during crystallization processes is a fundamental solid state engineering challenge. Here, for the first time, a general procedure is presented for designing continuous crystallizers that produce polymorphicly pure crystal distributions of a preferred polymorph regardless of that polymorph's relative thermodynamic stability. The design rules were generated by developing and analyzing a multi-polymorph mixed suspension mixed product removal precipitator model, and they have been corroborated both by experimental data generated in our lab and by all of the applicable data in the published literature. These design rules were originally developed to build understanding and aid in the process design of a carbon capture and utilization as structural materials process that requires the selective precipitation of thermodynamically metastable polymorphs of CaCO3. Other aspects of this process as well as interest in another sustainable energy technology (hydrogen production by molten metal methane pyrolysis) motivated the development of new models for calculating interphase mass transport in concentrated, electrolytic, reacting solutions and for three-phase membrane reactors. The development and analysis of these additional models and a thermodynamic minimum energetic cost assessment of a wider set of sustainable energy technologies are included in the dissertation, but they will not be discussed in detail during the defense presentation due to time constraints.