Testing of a highly reactive impregnated Fe2O3/Al2O3 oxygen carrier for a SR–CLC system in a continuous CLC unit

• Published in: Fuel processing technology Vol. 96; pp. 37 - 47
• Main Authors: Gayán, Pilar, Pans, Miguel A., Ortiz, María, Abad, Alberto, de Diego, Luis F., García-Labiano, Francisco, Adánez, Juan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2012; Elsevier
• Subjects: aluminum oxide; Applied sciences; burning; carbon; carbon dioxide; Chemical looping combustion; CO2 capture; combustion; Energy; Energy. Thermal use of fuels; Exact sciences and technology; fluidized beds; Fuels; heat; Hydrogen; hydrogen production; inventories; Iron oxide; methane; oxygen; Oxygen carrier; steam; Steam reforming; Oxygen carrier; Steam reforming; Iron oxide; CO2 capture; Hydrogen; Chemical looping combustion; Methane; Fluidized bed reactor; Gaseous fuel; Thermogravimetry; CO2 sequestration; Composition effect; Fuel gas; capture; Agglomeration; Iron; Endothermic reaction; Fluidization; CO; Attrition; Alumina; Combustion efficiency
• ISSN: 0378-3820; 1873-7188
• DOI: 10.1016/j.fuproc.2011.12.008

A Fe‐based oxygen carrier (OC) was evaluated for H2 production with CO2 capture by coupling steam reforming of methane and chemical‐looping combustion (CLC) processes (SR–CLC). The CLC system supplies the heat necessary to carry out the endothermic reformed reactions, using the PSA off‐gas as fuel. The Fe‐based OC was made by incipient hot impregnation using Al2O3 as support and was first characterized by TGA and batch fluidized bed reactor in order to determine its reactivity and its fluidization behavior. The OC behavior in a continuous CLC unit was evaluated using a simulated PSA off‐gas and methane as fuels. During 46h of continuous operation, the OC never showed agglomeration or carbon deposition, and the attrition was moderate. It was found that the fuel composition has low effect on the combustion efficiency and full conversion can be obtained at 1153K with an oxygen carrier‐to‐fuel ratio>1.5. The solids inventory needed to fully convert methane or PSA off‐gas was lower than those found with other Fe‐based materials. These results were due to the positive effect of the alumina on the OC reactivity. Therefore, the Fe2O3/Al2O3 OC prepared by impregnation is suitable for burning a PSA off‐gas in the SR–CLC process. ► An impregnated Fe2O3/Al2O3 carrier was evaluated for the SR–CLC process. ► The carrier was used in a continuous CLC unit to burn a PSA tail gas and CH4. ► Full conversion of PSA-offgass and CH4 at 880°C was obtained. ► The metal inventory needed is much lower (50kg/MWth) than for other Fe-based OC.