Experimental investigation on the oxy-fuel co-combustion behavior of anthracite coal and spent coffee grounds.

The combustion behaviors of anthracite coal/spent coffee grounds under oxy-fuel condition were assessed by a thermal analysis technique. At heating rates of 10-40 K min, the ignition temperatures and burnout temperatures of all anthracite coal/spent coffee grounds blends decreased with increasing the blending ratios of biomass or oxygen contents in O/CO atmospheres. The ignition temperatures of all samples at the similar oxygen content in oxy-fuel with that of air were higher than that in air atmosphere. In 30 % O/70 % CO atmosphere, the average ignition and comprehensive performance indices of anthracite coal/spent coffee grounds at 40 K min were about 4 times and 18 times more than that at 10 K min, respectively. At heating rate of 20 K min, the comprehensive performance indices of all samples in 30 % O/70 % CO were very close to those in air. In air and O/CO (21-40 % oxygen contents) atmospheres, the activation energies of release and combustion for volatile matters in the blends ranged from 33.66 to 147.32 kJ mol. Activation energies of char combustion in the blends ranged from 21.06 to 109.49 kJ mol. There were more significant synergistic effects between anthracite coal and spent coffee grounds during co-combustion in air and oxy-fuel atmospheres at 40 K min. [ABSTRACT FROM AUTHOR]