CAREER: Influence of electric fields on liquid-to-solid phase change associated with clathrate hydrate formation

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CAREER: Investigation of the fundamental mechanisms underlying electric field-induced formation of hydratesClathrate hydrates are water-based crystalline solids consisting of a guest molecule (methane, carbon dioxide, tetrahydrofuran, cyclopentane and others) trapped in a lattice of water molecules. Hydrates can be the basis of novel applications in many energy-water related areas such as natural gas transportation, desalination and carbon sequestration. A significant challenge associated with hydrate formation is the long wait time before hydrates start forming (nucleate), which can range from hours to days. Recent studies indicate that applied electrical voltages can significantly accelerate hydrate formation, and reduce the wait time by a factor of hundred or more. This electro-nucleation concept can enable rapid and controlled synthesis of hydrates for the above applications, all of which require rapid hydrate formation. This project is a fundamental study of the mechanisms underlying electric-field induced formation of hydrates. The influence of electric charge, current flow, heat transfer and surface chemistry on hydrate formation will be analyzed for three kinds of hydrates. Overall, this work will lead to seminal contributions in the fields of hydrates and liquid-to-solid phase change. The results of this project have the potential of completely eliminating the delay in hydrate formation, and enabling "on-demand" hydrate formation. Results from this research will be integrated into educational activities, which include the development of a graduate level course on Phase Change Heat Transfer and research opportunities for undergraduates and under-represented minorities. This project studies the electro-nucleation of three kinds of hydrates. In the first set of studies, hydrate formation from two immiscible liquids will be analyzed. Cyclopentane hydrate formation will be studied via experiments and analytical modeling to quantify the role of electric fields and interfacial charge on hydrate nucleation. In the second set of studies, hydrate formation from miscible liquids will be analyzed. Tetrahydrofuran hydrate formation will be analyzed to understand the influence of electric current and the resultant bubble generation on nucleation. The third set of studies will analyze electro-nucleation of methane hydrates, wherein hydrates nucleate at a liquid-gas interface at elevated pressures. This project includes nucleation-measurement experiments, analytical multiphysics modeling, and correlation development. Microfluidic cells will be fabricated to obtain statistically meaningful estimates of electro-nucleation. Specific outcomes of this project include measurements of electro-nucleation rates, and an understanding of the physics underlying the formation of various hydrates. This project will highlight the role of electric fields in fundamentally changing the nature of nucleation from stochastic to deterministic. Overall, this research will enable an in depth understanding of the influence of electrical phenomena on micro/mesoscale thermo-fluidic phenomena associated with hydrate formation.