- Title
- Selection of suitable oxygen carriers for chemical looping air separation: a thermodynamic approach
- Creator
- Shah, Kalpit; Moghtaderi, Behdad; Wall, Terry
- Relation
- Energy & Fuels Vol. 26, Issue 4, p. 2038-2045
- Publisher Link
- http://dx.doi.org/10.1021/ef300132c
- Publisher
- American Chemical Society (ACS)
- Resource Type
- journal article
- Date
- 2012
- Description
- The increasing demand for oxygen combined with the need for improved economic performance necessitates the search for alternative methods of oxygen production. Chemical looping air separation (CLAS) is one of these alternatives with a relatively small energy footprint. The present paper describes the results of a comprehensive thermodynamic study conducted by our group to identify suitable oxygen carriers for CLAS at medium to low temperatures. The thermodynamic simulations were carried out using Fact-Sage 6.1 for 20 different metal oxides forming 40 oxygen carrier systems. An Ellingham diagram was developed to relate the Gibbs free energy of the relevant reactions to the temperature for all metal oxide systems. Furthermore, the equilibrium partial pressure of oxygen was calculated at elevated temperatures. The mass balance calculations were also performed for identifying the steam/CO₂ requirements for the reduction reactor. On the basis of the comprehensive thermodynamic study, oxides of manganese, cobalt, and copper have been found most suitable for the CLAS process. Additionally, the possibility of carbonate and hydroxide formation during the reduction with CO₂ and steam, respectively, was calculated. The formation of the mixed oxide phases or the spinel structures between the metal oxides and various supports (such as SiO₂ and Al₂O₃) has also been thermodynamically investigated. Several other important factors were also qualitatively assessed. The Cu oxides with SiO₂ and the Co oxides with Al₂O₃ were found to be the most suitable oxygen carriers for CLAS.
- Subject
- chemical looping air separation; oxygen production; CLAS; oxygen carriers
- Identifier
- http://hdl.handle.net/1959.13/1307094
- Identifier
- uon:21329
- Identifier
- ISSN:0887-0624
- Language
- eng
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