High thermal stability Si-Al based N-carrier for efficient and stable chemical looping ammonia generation. (1st October 2022)

• Record Type: Journal Article
• Authors: Xiong, Chuhao; Wu, Ye; Feng, Mingqian; Fang, Jing; Liu, Dong; Shen, Laihong; Argyle, Morris D.; A. M. Gasem, Khaled; Fan, Maohong
• Is Part Of: Applied energy. Volume 323(2022)
• Publication Date: 2022-10-01
• Subjects: Chemical looing ammonia generation (CLAG) -- Cyclic N-sorption/desorption performance -- Si-modified alumina-based N-carrier -- High thermal stability -- Catalytic N-carrier -- Zirconia support; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2022.119519
• Languages: English
• ISSNs: 0306-2619

Abstract

Graphical abstract: Highlights: The cyclic N-sorption/desorption characteristics of the N-carriers were studied. The Si-modified Al2 O3 N-carrier enhanced the cyclic N-sorption/desorption performance. Loading Si-modified Al2 O3 N-carrier on ZrO2 could increase the NH3 yield and selectivity. The nitriding and ammoniating conversion efficiency maintained at about 71% and 60% respectively in five cycles. Abstract: Chemical looping ammonia generation (CLAG) is a promising NH3 production technology due to its potential for high yield of NH3 and low CO2 emission footprint. However, the stabilities of the existing N-carriers are problematic during the cyclic N-sorption/desorption. This research was designed to overcome that challenge through use of elemental doping and depositing the N-carrier on a support. The experimental results show that the N-sorption/desorption performance of γ-Al2 O3 N-carriers decreased with cycling due to the deterioration of the pore structure and phase transformation. A Si-modified alumina-based N-carrier, with a Si: Al molar ratio of 1:20 prepared by co-precipitation, was much more resistant to high-temperature phase transition and collapse of pore structure, resulting in highly stable cyclic N-sorption/desorption performance. Use of ZrO2 as a support for the Si-modified Al-based N-carrier further reduced NH3 decomposition and thus increased the NH3 yield and selectivity by 85.6% and 53.6% compared to that obtained with the pure γ-Al2 O3 N-carrier.