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Redox property and kinetics of copper oxygen carrier under different oxygen concentrations
Author(s) -
Wang Kun,
Yu Qingbo,
Wu Tianwei,
Qin Qin
Publication year - 2015
Publication title -
environmental progress and sustainable energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.495
H-Index - 66
eISSN - 1944-7450
pISSN - 1944-7442
DOI - 10.1002/ep.12228
Subject(s) - oxygen , chemical looping combustion , redox , chemistry , limiting oxygen concentration , kinetics , copper , nucleation , chemical stability , inorganic chemistry , chemical engineering , materials science , organic chemistry , physics , quantum mechanics , engineering
Chemical looping with oxygen uncoupling and chemical looping air separation technologies all depend on the redox property of oxygen carrier. The present work investigated the redox properties of Cu/Zr oxygen carrier under different oxygen concentrations by TG technique. The durability and stability of oxygen carrier is also investigated under 1065°C reduction and 800°C oxidation temperatures. For reduction, the starting and ending temperatures and the peaks of DTG curves shift to high values with oxygen concentration increasing. The effect of oxygen concentration on oxidation is little and the regeneration of Cu/Zr oxygen carrier can be achieved in thin oxygen environment. For reduction and oxidation, times for complete conversion decrease with heating rates increasing. Kinetic models were proposed based on the nucleation and nuclei growth model. The reduction mechanism function is: f ( α ) = 3 ( 1 ‐ α ) [ ‐ ln ( 1 ‐ α ) ] 2 / 3and the oxidation mechanism function is: f ( α ) = 1.5 ( 1 ‐ α ) [ ‐ ln ( 1 ‐ α ) ] 1 / 3. For reduction, the values of E and A all increase as oxygen concentrations increase and heating rates decrease. For oxidation, the values of E and A are almost the same. The Cu/Zr oxygen carrier has high stability and it is a good candidate for chemical looping technologies at high temperatures. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 531–539, 2016