Comparison of pyrite cinder with synthetic and natural iron-based oxygen carriers in coal-fueled chemical-looping combustion

Pyrite cinder, a Fe2O3-containing industrial waste derived from the sulfuric acid manufacturing industry, was compared with the synthetic and natural iron-based oxygen carriers, to explore its potential superiority in coal-fueled chemical-looping combustion. The oxygen carriers were evaluated through a lab-scale fluidized-bed reactor regarding their reactivity, recyclability, and attrition performance. The results showed that pyrite cinder prevailed over synthetic and natural iron-based oxygen carriers in terms of the reactivity. Similar CO2 yields were obtained by both pyrite cinder and synthetic Fe-Al(10nm) oxygen carrier, but the char conversion rate for pyrite cinder was obviously higher than that of synthetic and natural iron-based oxygen carriers. As for the cyclic reaction behavior, both pyrite cinder and natural MAC iron ore performed well regarding the stable yield of CO2, whereas synthetic Fe-Al(10nm) oxygen carrier showed a poor resistance to the decay of reactivity and occurrence of severe sintering. The attrition performance of three oxygen carriers under different operation parameters showed that the particle collision and the collisions between oxygen carrier particle and reactor wall were the major triggers to the attrition. The cyclic attrition tests showed that the abrasion-resistant capability for the pyrite cinder pelletized by the double-roller squeezing granulation method was lower than that of synthetic and natural iron-based oxygen carriers. It can be concluded that the pyrite cinder would be an outstanding candidate as the iron-based oxygen carrier, but its mechanical strength should be enhanced before produced in large scale. (c) 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.