Hydrogen production using chemical looping technology: A review with emphasis on H2 yield of various oxygen carriers

Natural H-2 in useful quantities is negligible, which makes hydrogen unsuitable as an en-ergy resource compared to other fuels. H-2 production by solar, biological, or electrical sources needs more energy than obtained by combusting it. Lower generation of pollutants and better energy efficiency makes hydrogen a potential energy carrier. Hydrogen finds potential applications in automobile and energy production. However, the cost of pro-ducing hydrogen is extremely high. Chemical-looping technology for H-2 generation has caught widespread attention in recent years. This work, presents some recent findings and provides a comprehensive overview of different chemical looping techniques such as chemical looping reforming, syngas chemical looping, coal direct chemical looping, and chemical looping hydrogen generation method for H-2 generation. The above processes are discussed in terms of the relevant chemical reactions and the associated heat of reactions to ascertain the overall endothermicity or exothermicity of the H-2 production. We have compared the H-2 yield data of different Fe/Ni, spinel and perovskites-based oxygen carriers (OC) reported in previous literature. This review is the first comprehensive study to compare the H-2 yield data of all the previously reported oxygen carriers as a function of temperature and redox cycles. In addition, the article summarizes the characteristics and reaction mechanisms of various oxygen carrier materials used for H-2 generation. Lastly, we have reviewed the application of Density Function Theory (DFT) to study the effect of various dopant addition on the efficiency of H-2 production of the oxygen carriers and discussed ASPEN simulations of different chemical looping techniques.(C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This article discusses the limitations of hydrogen as an energy resource, as well as the methods of producing hydrogen using solar, biological, or electrical sources. Chemical-looping technology has gained widespread attention in recent years as a way to produce hydrogen, with the article also comparing the H-2 yield data of different oxygen carriers.