Red mud as promising oxygen carrier in chemical looping gasification of distilled spent grain from Chinese baijiu production

Abstract

In this study, red mud was employed as an oxygen carrier (OC) in the chemical looping gasification (CLG) of distilled spent grain with husk (DSGH) from Chinese baijiu. The components of DSGH were found to be very complex. The presence of peptides and amino acids reduced the initial thermal decomposition temperature to as low as 197 °C. The activation energy during the initial combustion stage was also low (less than 280 kJ mol⁻¹). Chemical looping gasification, with red mud as an OC, proved feasible for processing DSGH, producing high-quality syngas. Gasification temperature was a more important factor than steam concentration in CLG. The activity of lattice oxygen was more affected by gasification temperature, and steam concentration mainly influenced the process by promoting carbon gasification, methane reforming, and altering the water-gas shift (WGS) equilibrium. A 30-redox-cycle test demonstrated the excellent stability of red mud as an OC, making it a promising candidate for CLG of DSGH.