Evaluation of Fe-Ni Composite Oxygen Carrier in Coal Chemical Looping Gasification

Abstract

Although coal chemical looping gasification (CCLG) is a promising technology for the efficient utilization of coal, limited studies concerned about the industrial application of oxygen carrier in CCLG system owing to its performance requirements including high reactivity with solid fuel, high carbon conversion, and good mechanical property. To meet the requirements of oxygen carriers in CCLG system, novel Fe-Ni composite oxygen carrier (OC) samples were successfully prepared. The performances of these OCs were evaluated in a fixed bed reactor, where they were reduced by solid fuel and then fully oxidized by air. Both fixed bed tests and thermodynamic analysis showed that the prepare OCs exhibited high reactivity with coal and syngas selectivity, making them suitable for the CCLG process. Specifically, when the loading amount of NiO was 20 wt%, the Fe-Ni composite OCs achieved the highest carbon conversion (93.03%) and synthesis gas selectivity (73.29%). Additionally, the thermogravimetric data revealed that the Curie temperature of the OCs was higher than 550°C, making them suitable for magnetic separation of the OC particles and carbon residue in the CCLG system.