Abstract
Iron-based oxygen carriers supported on alumina or alumina/titania were fabricated and evaluated for chemical looping combustion of isopropanol (IPA). Hydrogen is the major combustible gas generated by IPA decomposition prior to combustion with oxygen carriers at temperatures above 800°C. Nearly complete combustion (above 95%) of IPA was achieved for experiments conducted with fabricated Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 operated at lower inlet IPA flow rates. Carbon deposition during the chemical looping combustion of IPA was minimized using Fe2O3/Al2O3/TiO2 as an oxygen carrier. The reduction of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 by hydrogen was markedly increased with increasing inlet hydrogen concentration (5–20%), and was not obviously influenced by operating temperature (875–925°C). According to the shrinking core model, the mass transfer coefficients (kg) of Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 reduction with H2 were found to be 0.22 and 0.24 mm s–1, while the effective diffusion diffusivity (De) of Fe2O3/Al2O3 oxygen carriers was more easily depended on the oxygen carrier conversion. The higher reduction conversions obtained for experiments conducted with Fe2O3/Al2O3/TiO2 because it can be further reduced to FeO and Fe; comparing to those with Fe2O3/Al2O3, which is primarily reduced to FeO. Hydrogen molecules are found to diffuse more easily through the FeO product-layer on Fe2O3/Al2O3 than the FeO/Fe product-layer on Fe2O3/Al2O3/TiO2.
Highlights
Liquid waste combustion by chemical looping technology is aimed to eliminate liquid waste and simultaneously to generate hydrogen and/or heat
More than 95% IPA was combusted for most experiments conducted in the moving-bed reactor with fabricated Fe2O3/Al2O3 and Fe2O3/Al2O3/TiO2 operated at inlet IPA flow rate ranged from 4.1 to 5.8 mmol min–1 and 4.1 to 7.2 mmol min–1, respectively; in addition, the oxygen carrier conversions were respectively reached less than about 16.3% and 17.5%
Major crystalline phases generated during the chemical looping combustion of IPA with Fe2O3/Al2O3
Summary
Liquid waste combustion by chemical looping technology is aimed to eliminate liquid waste and simultaneously to generate hydrogen and/or heat. Serrano et al (2017) investigated the application of Fe2O3/Al2O3 for chemical looping of combustion diesel and lubricant oil, and reported that the reactivity of Fe2O3/Al2O3 oxygen carriers was not affected by sulphur or impurities present in the Aerosol and Air Quality Research | https://aaqr.org fuels. This is because the formation of iron sulfide is thermodynamically feasible only under substoichiometric conditions (fuel-rich), so sulphur does not react with the components existing in the Fe-based oxygen carrier during the combustion process
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
