Implications of wood pyrolysis intensity considering a combined production of solid blast furnace injectants and hot blast stove fuel gas

The utilization of wood as energy source for the production of high-quality iron and steel necessitates significant fuel upgrading. The process of carbonization, referred to as torrefaction or pyrolysis, is considered an effective strategy for this upgrading, wherein wood is separated into solid and gaseous product streams. This study evaluates the implementation of such a carbonization facility within steelworks and examines the implications of the selected treatment strategies. The study assesses the use of the solid product as a substitute for injection coal, as well as the application of the corresponding gaseous products in the hot blast stoves, across various treatment strategies, wood characteristics, and scenarios of pyrolysis gas utilization. An integration of mass and energy balances for the thermal treatment stage and the blast furnace and periphery was established, presenting an encompassing method to evaluate accurate wood carbonization intensities. The findings indicate that a favorable substitution outcome is probable for projected energy prices in 2030 under the European Union regulatory framework, with optimal treatment strategies yielding solid phase between 0.4 and 0.3. Moreover, the importance of enhancing bioreductant carbon yields and increasing pyrolysis gas utilization is underscored, as these factors facilitate substantial improvements in efficiency and CO2 emission reduction.