Development of CuFeMnAlO4+δ oxygen carrier with high attrition resistance and 50-kWth methane/air chemical looping combustion tests

•Highly attrition resistant CuFeMnAlO4+δ oxygen carrier.•Incorporation of Mn increased attrition resistance by lowering carbon formation and alumina segregation.•Successful commercial preparation of 180 Kg CuFeMnAlO4+δ with natural ore and pigment grade raw materials.•Low oxygen carrier make-up cost observed during 50 kWth chemical looping combustion (CLC) 54 hr. test.•Estimated oxygen carrier Make-up cost less than $1.5/(MWhth) A Copper-Ferri-Manganese-Aluminate spinel (CuFeMnAlO4+δ) oxygen carrier, developed at the US Department of Energy’s (DOE) National Energy Technology Laboratory (NETL), shows promising results for chemical looping combustion with methane. Attrition resistance of the spinel oxygen carrier (160–600 µm) produced by a wet agglomeration method was significantly higher than that observed previously with a Copper-Ferri-Aluminate (CuFeAlO4) oxygen carrier. Improved attrition resistance of the novel carrier can be attributed to minimal alumina phase segregation and minimal carbon formation. Heats of reaction measured by differential scanning calorimetry indicated exothermicity during reduction with methane. The total oxygen transfer capacity of the material was about 10.5 wt% at 850 °C. The attrition resistance and the oxygen transfer capacity of the carrier prepared at a commercial manufacturing facility (180 kg) were very similar to observed values during the development phase with the lab scale preparations. The material displays satisfactory methane conversion and significantly high particle durability during a 54 h test campaign conducted in NETL’s 50-kWth chemical looping dual fluid bed reactor unit at temperatures ranging from 700 to 900 °C. Low oxygen carrier make-up cost, due to the use of natural ore and pigment grade raw materials during synthesis and very low attrition rates, exceeded the performance goals determined by systems studies.