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Sustainable hydrogen production process development using reducible oxides

2020
Çalışan, Atalay
The energy demand is driven by increasing world population and living standards. Sustaining this demand with available and renewable energy sources is a major challenge. The options such as solar and wind power, are unreliable for a steady energy production due to their intermittent nature. Therefore, the storage of renewable energy, such as hydrogen, gains importance. In the scope of this thesis, a sustainability barrier in front of solar integrated hydrogen production processes was addressed in terms of material development and energy utilization perspectives for the two step thermochemical cycles and methane reforming processes. From the material development perspective, thermodynamic analysis was performed for investigating the driving force towards metal oxygen bond breaking and bond formation. The effect of reaction control mechanisms on the processes is studied through temperature programmed experiments etc. Conducted experiments revealed that hydrogen yield (maximum 52.5 mL/g MO¬¬x) was limited by heat and mass transfer resistances as well as a severe thermodynamic barrier in front of metal oxygen bond breaking. The studied red/ox couples were also investigated in conventional methane reforming process. Thereafter, solar energy integration to methane reforming process was studied for sustaining reaction energy from solar. Simulations performed by ASPEN Plus revealed that the solar energy losses observed in a daily basis is overcame with an integrated combustion zone to solar reformer, so a unique hybrid process was proposed for uninterruptable hydrogen production. The demonstration of this proposed process under real environment was left as a future subject.