8th International Congress on Science and Technology of Ironmaking - ICSTI 2018

The benefits of biomass usage as renewable energy source and reducing agent in the steel industry, particularly, by its injection into the blast furnace tuyeres is known. This contribution focuses on two aspects, which could increase the economic efficiency of this technology. The first one is related to the thermal treatment of biomass. Woody biomass waste and biomass residues were pyrolysed in a laboratory scale screw continuous reactor at different temperature profiles. Besides charcoal, yields of organic liquid and a gas mixture consisting of carbon oxides, light hydrocarbons and hydrogen were considered. The share and quality of these three fractions can be controlled by the pyrolysis parameters such as temperature, heating rate, residence time or presence of catalysts. The second aspect is related to the optimisation of grain size of injected solids. Different grain size fractions in the range from about 0.1 to 1.8 mm were prepared and tested using a batch injection rig. Furthermore, microstructure of samples were examined. Results were compared with PC. It was concluded that coarser grinding of charcoal than that for coal can be sufficient for its conversion in the blast furnace raceway. The microstructure of charcoals may have a great influence on their conversion behaviour along with the chemistry. The effect of injection rate on conversion rate depends on grain size of charcoal.