Experimental investigation of chemical-looping combustion in packed beds : a parametric study

Recently a novel reactor concept for chemical-looping combustion (CLC) has been proposed exploiting dynamically operated packed beds. In this work, an experimental parametric study on this reactor concept has been carried out. The effects of operating temperature, feed oxygen concentration, steam addition, and type of oxygen carrier material (CuO/Al2O3 and CaMnO3) have been evaluated. It has been found that an increase of the reduction temperature resulted in a higher conversion of the oxygen carrier, increased reduction reaction rates, and increasing significance of various side-reactions. Steam addition suppresses carbon deposition on the oxygen carrier. Interesting insights in the relevance of steam reforming and water-gas shift during the reduction cycle were obtained. Finally, CaMnO3 is of interest for CLC in packed beds in view of the high oxygen capacity of the material and the excellent selectivity to the formation of CO2.