Using Biomass for Pig Iron Production: A Technical, Environmental and Economical Assessment

The classical route for iron- and steel-making today is based on massive use of fossil coal, which is responsible for most of the large CO2 emissions of the steel industry. Biomass, as a renewable carbon resource, is a good candidate to substitute for fossil coal and even partial substitution could lead to a significant reduction in CO2 emissions. Depending on the type of biomass, its processing, and the way it is used in the iron making process, many different scenarios may be considered. Those scenarios should be evaluated and compared from technical, environmental, and economical points of view in order to figure out the best options. The case of a real pig iron plant located in the North East of France was investigated. First, we checked the relevance of various biomass options on the basis of the biomass availability around the plant and of the technical requirements of the processes. Then, we carried out a screening life cycle assessment focusing on global warming impacts and following a cradle-to-gate approach. Different biomass-based pig iron production scenarios were compared. The results showed that for a 20 % substitution of biomass for coke, around 300 kg of CO2-equivalent per ton of pig iron produced could be saved, which represents a reduction of 15 % in the total greenhouse gas emissions. Finally, a brief economic evaluation of the resulting scenarios was performed.