Study of chemical looping co-gasification (CLCG) of coal and rice husk with an iron-based oxygen carrier via solid–solid reactions

Abstract

The chemical looping gasification (CLG) is a promising gasification technology for syngas production. It reduces the demand for pure oxygen and heat from outside by the cycle of oxygen carriers. The lattice oxygen is transferred by oxygen carrier like Fe2O3 in CLG. Considering the synergy between lignite and rice husk, the chemical looping co-gasification (CLCG) of lignite and rice husk with Fe2O3 as oxygen carrier was studied in this work. The mass loss of lignite increased by about 3% with the help of rice husk. Due to the synergetic effect, rice husk developed the pyrolysis of coal in the co-gasification. It is found that the most contributing reaction at around 800 °C–1000 °C in CLG is the gasification of char with Fe2O3via solid-solid reactions. The kinetic fitting was used to explore the reaction mechanism of CLCG. The modified random pore model (MRPM) fitted the experimental data well, which confirmed the solid-solid reactions between char and Fe2O3, and the synergy between lignite and rice husk in CLCG. Finally, the gas analysis was conducted in a fixed bed system with gas analyzers. It is found that Fe2O3 enhanced the concentration of CO and CO2 in CLG process.