Oxygen enriched co-combustion characteristics of herbaceous biomass and bituminous coal

•The samples were investigated using thermogravimetric analysis.•The incorporation of beetroot or switchgrass improve the combustion of the coal.•The ignition tempeatures and burnout tempeatures of co-combustion are determined.•The comprehensive performance indices of blends and their parents are determined.•Significant interactions between bituminous coal and beetroot or switchgrass.

The oxy-fuel co-combustion behavior of two different herbaceous biomass species (beetroot and switchgrass) with bituminous coal was investigated by thermal gravimetric analysis (40 °C/min). The effects of sample kinds, oxygen concentrations and blend ratios on the co-combustion characteristics were obtained. The results showed that the incorporation of the beetroot or switchgrass could improve the combustion characteristics of the bituminous coal. The ignition temperatures (Ti) of the blends were very close to the pure beetroot and switchgrass. The Ti values of the pure beetroot and beetroot/coal blends were lower than those of the pure switchgrass and switchgrass/coal blends. The Ti values and Tb values of blends and their parent samples decreased with increasing the oxygen concentration. The comprehensive performance indices of blends and their parent samples increased with increasing the oxygen concentration. A significant interaction was detected between the bituminous coal and the beetroot or switchgrass during the oxy-fuel co-combustion.