H2 production from a plasma-assisted chemical looping system from the partial oxidation of CH4 at mild temperatures

Zheng, Yaoyao; Marek, Ewa; A. Scott, Stuart

Abstract

A plasma-assisted chemical looping system for the production of H2 (PCLH) was investigated in this study. This system allows the partial oxidation of CH4 at mild temperatures (573–773 K). Four active oxygen carriers: Fe2O3, NiO-impregnated Fe2O3 (NiO/Fe2O3), SrFeO3−δ and NiO-impregnated SrFeO3−δ (NiO/SrFeO3−δ) were compared, each working both as a packed material for the plasma reactor and an oxygen source for the partial oxidation of CH4. Similar conversions of CH4, and low yields of H2 were obtained in Fe2O3 and SrFeO3−δ. It was concluded that in these cases, H2 was mainly produced from direct cracking of CH4 by plasma. In contrast, when using NiO/Fe2O3 and NiO/SrFeO3−δ, substantial production of H2 was achieved. It is proposed that there is a synergistic effect between the catalyst and the oxygen carrier; the presence of the metallic Ni phase was responsible for catalysing the production of H2, and the oxygen from the support helped prevent the build-up of coke. As a result, the activity of Ni was continuously maintained for H2 production. The chemical loop is closed with the oxygen carriers being regenerated in air with plasma and then used in the next looping cycle. The high H2 production capability in NiO/Fe2O3 was repeatable; whilst, NiO/SrFeO3−δ deactivated in the second and third cycles. Amongst the temperatures studied, NiO/Fe2O3 at 673 K resulted in the best performance for H2-rich gas production. A further increase in the operating temperature led to a total combustion of CH4.

Citation

Zheng, Y., Marek, E., & A. Scott, S. (2020). H2 production from a plasma-assisted chemical looping system from the partial oxidation of CH4 at mild temperatures. Chemical Engineering Journal, 379, Article 122197. https://doi.org/10.1016/j.cej.2019.122197

• Journal Article Type: Article
• Acceptance Date: Jul 9, 2019
• Online Publication Date: Jul 13, 2019
• Publication Date: Jan 1, 2020
• Deposit Date: Apr 3, 2024
• Publicly Available Date: Apr 24, 2024
• Journal: Chemical Engineering Journal
• Print ISSN: 1385-8947
• Electronic ISSN: 1873-5606
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 379
• Article Number: 122197
• DOI: https://doi.org/10.1016/j.cej.2019.122197
• Public URL: https://nottingham-repository.worktribe.com/output/32757533
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S1385894719315918?via%3Dihub