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Kinetics Analysis of Ammonia Electrolysis

Wednesday, May 14, 2014: 09:05
Nassau, Ground Level (Hilton Orlando Bonnet Creek)
L. A. Diaz and G. G. Botte (Ohio University)
Introduction

 

When ammonia electro-oxidation in alkaline media is coupled with water reduction, in a process known as ammonia electrolysis [1], it is theoretically possible to produce hydrogen with just five percent of the energy required from water electrolysis [2,3]. However, the lack of understanding of the reaction mechanism and reaction kinetics has not allowed the full utilization and implementation of the technology in processes such as the removal of ammonia from wastewater [4].

In this work, it is discussed a methodology for the elucidation of a reaction mechanism and the kinetics parameters for ammonia electro-oxidation in a well characterized polycrystalline Pt electro-catalyst. Experimental data and mathematical modeling of a rotating disk electrode system were combined with parameter estimation to obtain information about the intrinsic kinetics of the ammonia electro-oxidation reaction.  The validation of the reaction mechanism and kinetics parameters was supplemented by the analysis of a fluid cell electrolyzer.

Valuable information regarding operation conditions and catalyst deactivation were obtained from the mathematical model and corroborated with the fluid cell system. Finally it was possible to observe the scalability advantage of the developed methodology and the application of the calculated kinetic parameters for the ammonia electro-oxidation simulation and process design.

References

[1] G. G. Botte. (2010). U.S. Patent No. 7,803,264.

[2] F. Vitse, M. Cooper, G.G. Botte, J.  Power Sources 142 (2005) 18.

[3] F. Vitse, M. Cooper, G.G. Botte, J.  Power Sources 152 (2005) 311.

[4] L.A. Diaz, G.G. Botte, Ind.  Eng.  Chem.  Res. 51 (2012) 12167.