Co-combustion kinetic analysis of biomass hydrochar and anthracite in blast furnace injection

•Hydrochar was low ash and better combustion performance to be used in blast furnace injection.•The alkali metal content in ash of hydrochar has a synergistic effect on the combustion of mixed fuel.•When the proportion of hydrochar was 60%, the combustion activation energy of mixed fuel is the lowest.•Hydrochar injection in blast furnace has significant effect on energy saving and carbon reduction.