Influence of particle size on combustion behavior of bamboo char used for blast furnace injection

The combustion behavior of bamboo char and its relationship with particle sizes were evaluated using thermo-gravimetric analysis.The results showed that the combustion properties of bamboo char were much better than those of the anthracite used as a coal injected for blast furnace ironmaking due to its porous structure,disordered microcrystalline and higher catalytic index of ash minerals.When the particle size increased from -0.074 to 0.500-1.000 mm,the ignition temperature and burnout temperature of bamboo char increased,while the combustible index and comprehensive combustion characteristic index decreased slightly.The apparent activation energies of non-isothermal combustion of bamboo char and anthracite were calculated based on the distributed activation energy model.The results showed that the average activation energy was 162.86 kJ/mol for-0.074 mm anthracite,while it ranged from 71.01 to 89.44 kJ/mol for bamboo chars of different sizes.It revealed that the combustion reactivity of bamboo char in the largest size (0.500-1.000 mm)was much better than that of -0.074 mm,anthracite;thus,the size of biomass char could be enlarged to the maximum size specified by the injection application of blast furnace.