Copper manganese oxides as oxygen carriers for chemical looping air separation for near-zero emission power generation
File(s)
Author(s)
Patzschke, Clemens Frederic
Type
Thesis
Abstract
In this thesis, copper manganese oxides were evaluated as oxygen carriers for chemical looping air separation. This process allows for the production of a O2+CO2 mixture, which can be used for oxy-fuel combustion of biomass for near-zero emission generation of power. Unsupported oxygen carriers were prepared via co-precipitation at low and at high super-saturation and via mechanical mixing. Furthermore, TiO2, ZrO2 and Al2O3-supported oxygen carriers were prepared. The oxygen carriers were characterised to study the effect of synthesis conditions on the material properties, and experiments in the TGA and fluidised bed were performed to assess their kinetic and long-term cycling performance. The unsupported oxygen carriers showed a highly stable cycling behaviour over a high number of redox-cycles. The O2 capacities and O2 equilibria were measured and the data reported. Cycled oxygen carriers were characterised to study the particle evolution for different redox-cycling modes (isothermal, non-isothermal, fuelled process with CH4) and at various conditions. The characterisation also elucidated the relevant redox-reactions and reaction pathways, as well as interactions between active phases and the supporting materials. During redox-cycling, the unsupported oxygen carriers were prone to swelling (an increase in the specific particle volume). It was demonstrated that the use of ZrO2 as a supporting material inhibits the swelling and result in a shrinking. Kinetic parameters were isolated from experiments in the fluidised bed, and the homogeneous reaction model was found to represent the O2 release and oxidation reaction best.
Version
Open Access
Date Issued
2019-02
Date Awarded
2019-03
Copyright Statement
Creative Commons Attribution NonCommercial Licence
Advisor
Fennell, Paul S.
Sponsor
Imperial College London
Publisher Department
Chemical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)