Education
- Ph.D., Chemical Engineering, Â鶹¹ÙÍø
The goal of my research is the discovery of a feasible means of transforming solar energy into chemical energy in the form of hydrogen, thus uncovering a renewable, sustainable pathway to the "hydrogen economy."Ìý The pathway I am focusing on is a solar thermal water splitting cycle utilizing metal oxides.Ìý A metal oxide (e.g. ZnO) is passed through a solar thermal reactor and undergoes a thermal dissociation reaction.Ìý The reduced metal or metal oxide is collected and the oxygen gas is allowed to escape.Ìý The reduced metal or metal oxide can then be fed to another reactor containing water, where an oxidation reaction occurs, splitting the water, releasing hydrogen, and forming once again the original metal oxide.Ìý This metal oxide can be recycled to the solar reactor, forming an overall cycle where the only feed is water and the only products are hydrogen and oxygen.
The solar thermal dissociation is performed in a high flux solar furnace, where radiant energy from the sun is concentrated up to 10,000 times by parabolic mirrors and focused on a chemical reactor.Ìý With this configuration, temperatures up to 3000 K and heating rates of 1,000,000 K/s can be achieved, providing access to reaction regimes not available to any other renewable energy technology.
The cycle currently of most interest to me utilizes zinc oxide (ZnO) as the metal oxide energy carrier.Ìý ZnO is used in the thermal dissociation step, and thermodynamic simulations suggest that it should react to completion between 2100 K and 2300 K.Ìý The water splitting step employs the reduced Zn metal, and will react exothermally around 700 K.Ìý Due to the exothermic nature of this reaction, it can be run autothermally.Ìý My current work with the ZnO cycle focuses on determining the intrinsic kinetics of the ZnO dissociation reaction and attempting to engineer methods to prevent recombination of the Zn and oxygen products in the cooling stage of the reactor.