Investigation of Rapid Zno Dissociation in an Aerosol Flow Reactor

Christopher Perkins1, Paul Lichty2, Tom Melchior3, Aldo Steinfeld4, and Alan W. Weimer2. (1) University of Colorado, 1111 Engineering Drive, Boulder, CO 8030900424, (2) Chemical and Biological Engineering, University of Colorado, 1111 Engineering Drive, Boulder, CO 8030900424, (3) ETH Zurich, Sonneggstrasse 3, Zurich, 8092, Switzerland, (4) Department of Mechanical and Process Engineering, ETH Zurich, Sonneggstrasse 3, ML J42.1, Zurich, 8092, Switzerland

The dissociation of ZnO is a critical reaction in a two-step water splitting process for the production of hydrogen, and the reaction can be performed in solar thermal reactors for sustainable hydrogen generation. Fundamental understanding of the reaction is critical to solar reactor design, and so the dissociation must be explored at residence times typical to these reactors (0.05s to 1.5s).

Dissociation of fine zinc oxide particles (<1 µm) was explored at ultra-high temperatures (1800-2100 K) using an alumina aerosol reactor heated in a graphite tube furnace, as well as in a solar simulator at the Swiss Federal Institute. Conversions between 10% and 30% were obtained at temperatures ranging between 1800 K and 2100 K and residence times scattered about 1.2 s. Computational fluid dynamics simulations were performed using reaction kinetics determined from thermogravimetric analysis, and the results were compared to the experimental conversions.