2nd International Conference on Chemical Looping, 26-28 September 2012, Darmstadt, Germany 1 Developing a Highly Reactive and Low Nickel Content Oxygen Carrier for Gaseous Fuels in CLC Arturo Cabello*, Pilar Gayán, Francisco García-Labiano, Alberto Abad, Luis F. de Diego and Juan Adánez Instituto de Carboquímica (ICB-CSIC), Department of Energy and Environment, Miguel Luesma Castán 4, Zaragoza 50018, SPAIN. *Arturo Cabello, acabello@icb.csic.es Abstract – The behavior of a Ni – based oxygen carrier with low NiO content (11.8 wt% NiO) prepared by impregnation on CaAl 2 O 4 has been studied in a continuous CLC unit (500 W th ) using different gases as fuels (methane, H 2 , CO, syngas, ethane and propane). More than 90 h of successfully operation at high temperature (900 ºC) have been carried out analyzing the effect of the oxygen carrier - to - fuel ratio and fuel gas composition regarding combustion efficiency and gas product distribution. Using syngas, pure CO or H 2 as fuels, full combustion can be achieved working at oxygen carrier - to - fuel ratios, φ, higher than 1.2. Regarding methane, the maximum fuel combustion efficiency is reached in a narrow range of φ values close to 1 (1.0 – 1.2). An increase in the value of this parameter produces a decrease in the combustion efficiency. This behavior is different to that found using most of the Ni-based oxygen carriers present in literature, and can be attributed to the low global catalytic activity of the reduced oxygen carrier for reforming reactions. When light hydrocarbons are used as fuels, the oxygen carrier presents a similar behavior than in the case of methane combustion tests, reaching to the maximum fuel combustion efficiency at the same φ values. This fact also indicates that light hydrocarbons combustion mechanism is carried out through cracking reaction. The solids inventory needed to obtain a methane combustion efficiency of 99 % is 180 kg/MW th , which corresponds to a metallic Ni inventory around 17 kg/MW th . This value is the lowest referred in the literature for any kind of Ni-based oxygen carrier. This remarkable result is due to the low NiO content (11.8 wt.%) and the very high reactivity of this oxygen carrier because all nickel in the particle is present as free NiO, since the formation of less reactive nickel compounds is avoided using CaAl 2 O 4 as inert support. 1 Introduction Nickel materials have received more attention than other candidates for CLC gas combustion due to its high reactivity and thermal stability at high temperatures (900 – 1100 ºC). However, due to the high cost and the special environmental-safety precautions that have to be taken with nickel-based materials, the current tendency in the development of CLC technologies