CaO sorbent stabilisation for CO2 capture applications

Large differences have been observed in CO2 sorption behaviour of various commercial calcium oxide materials during multi cycle sorption tests. ICP analyses of these materials have shown a significant variance in magnesium impurities within these materials. Because it is well known that magnesium can stabilize CaO sorbents, optimization of CaO for CO2 sorption has been performed by examining the effects of magnesium loading with respect to the pre-cursor, Mg-loadings and temperature treatments. Experiments have been performed in a fixed bed reactor at 650 degrees C in the presence of steam. The experimental results show that it is possible to improve the cyclic stability significantly. Loading with a small amount of magnesium (similar to 1wt%), followed by a high temperature treatment at 1000 degrees C results in a performance which is very similar to the commercial material with high magnesium impurities. The CaO show a stable cyclic capacity of 19% from the 150(th) cycle until the 250(th) cycle. Finally, Sorption Enhanced-Steam Methane Reforming experiments are performed with the stabilized material, resulting in an increased CH4 conversion to almost 100%. (C) 2011 Published by Elsevier Ltd.