Analysis of influence factors on co-combustion characteristics of bituminous coal with herbal biomass

For investigating the co-combustion characteristics of herbal biomasses with bituminous coal, the co-combustion characteristics of beet and switchgrass, with bituminous coal were studied by thermogravimetric experiments. The influences of samples kinds, heating rates and blend ratios on the co-combustion characteristics under air atmosphere were analyzed and compared with those of bituminous coal and biomasses. The results showed that the initial release temperatures of volatile for all samples decreased with the increase of blend ratio and heating rates. The ignition temperatures of blend fuels were much lower than that of bituminous coal, but slightly higher than that of pure biomasses. The heating rates and blend ratios had little influence on ignition temperature. Volatile matter release index and comprehensive characteristic index of samples only above mass percentage of 20% for biomasses presented an upward trend with the increasing of heating rates, and these indexes improved as blend ratio increased. The better co-combustion characteristics can be obtained at mass percentage of 80% for biomass with heating rate of 50℃/min. These indexes for blend fuels of switchgrass with bituminous coal were higher than that for blend fuels of beet and bituminous coal between heating rates of 10 to 90℃/min. The research can provide a reference for efficient utilization of biomass.