V. Amar, J. Puszynski, R. Shende
South Dakota School of Mines and Technology,
Keywords: thermochemical water-splitting, hydrogen, core-shell, immobilization, nanoscale ferrites
Summary:In this study, water was used as energy carrier for H2 generation via thermochemical water-splitting process using core-shell and immobilized nanoscale ferrite materials. Core-shell ferrite nanoparticles were synthesized using pluronic P123 templating assisted sol-gel method. Nanoparticles containing porous yttria shell and doped/undoped ferrite nanoparticles as core were synthesized and characterized by SEM/EDX, BET surface area analyzer and TEM. Immobilization of ferrite nanoparticles on highly porous ceramic supports was accomplished by soaking the support into a sol followed by gelation and calcination at 1000oC. These nanomaterials were thoroughly characterized to understand their phase composition by x-ray diffraction and utilized in a continuous flow through tubular reactor as a packed bed for thermochemical water-splitting process. First step of the process involves regeneration, which was carried out at 950 - 1150oC under continuous N2 flow of 35 SCCM, whereas the second step that refers to water-splitting was performed at 800-1100oC. Multiple thermochemical cycles were performed and H2 and O2 volumes were continuously recorded using the online sensors integrated with the reactor system. Thermal efficiency, and Fanning friction factor and Reynolds numbers for porous packed bed have been estimated for different nanomaterials. To accomplish H2 generation from water-splitting at the temperatures similar to steam methane reforming process, these ferrite nanoparticles were further modified by Li. It is possible that immobilized ferrite nanomaterials can be utilized as a packed-bed configuration for distributed H2 production system at 0.1 ton capacity, which is industrially relevant. Details on the synthesis methods, characterization, H2 and O2 production, energy and mass balance, and some process economics aspects will be presented.