Experimental and Computational Fluid Dynamics Studies on Hydrous Hydrazine Decomposition over the Ir/Ni10Ce Catalyst

Abstract

Hydrogen storage materials are promising as a fuel source for the adaption of a hydrogen-based economy toward more sustainable energy production. An example of such a material is hydrous hydrazine with a hydrogen content of 8.0 wt %. In this study, an iridium-based catalyst was developed via incipient wetness impregnation and used for hydrous hydrazine decomposition in a batch reactor for H2 generation. The reaction conditions were optimized in a batch reactor, and the results were validated utilizing computational fluid dynamics (CFD). The developed catalyst achieved a yield of over 80% and a TOF value of around 2400 h-1 at 80 °C. Upon validating the experimental data, CFD studies were performed to provide information on the mixing flow phenomena occurring in the reactor. A different batch reactor configuration was developed, which showcased a lower velocity magnitude compared to the original configuration. Models were developed using a one-dimensional (1D) stirrer and four different shapes of two-dimensional (2D) stirrers. The results among simulations using 1D and the 2D pivot ring stirrer did not vary significantly, validating the accuracy of the model. Given the small reactor size, the effect of a different shape was expected to be negligible; however, the smallest stirrer resulted in a poor mixing profile, highlighting the importance of appropriate mixing. The potential of using a packed-bed microreactor was also simulated. The yield reached a maximum value and then decreased due to the continuous generation of ammonia in addition to hydrogen. The outcomes of this study make a significant contribution to the integration of experimental data with CFD on the decomposition of hydrous hydrazine for catalytic green H2 generation, highlighting how reactor configurations influence reaction performance and providing insights for scalability on H2 technologies.