Preparation of bio coke from coking coal and high-moisture biomass-derivative for steel making

Bio coke has the potential to reduce the fossil-based materials in metallurgical processes, along with mitigating CO₂ emission, which is one of the major challenges of steel industry emitting 2.6 Gt CO₂ annually (7-9% of global emission). Our work focused on the preparation of bio coke by the utilization of wet biomass-derived bio coal with coal blend, which could work as metallurgical coke in steel industry. Bio coal was blended with coking coal (C_T) at different percentages (1%, and 2%) and sizes (1 mm and 2 mm). The FTIR analysis of bio coal suggested that it comprised oxygen-rich functional groups (aliphatic and aromatic -C-O-C, -OH, -COOH) showing no caking property. Gieseler fluidity of the bio coal-C_t blend decreased from 400 ddpm to 178.3 ddpm when bio coal percentage was increased to 2%. Coke quality was determined through coke reactivity index (CRI) and coke strength after reaction (CSR). A decrease in CSR and increase in CRI was observed for coke prepared using 1% and 2% bio coal-Cr blend for a bio coal size of 1 mm as compared to the Cr. When the bio coal size was increased to 2 mm, coke quality of 1% and 2% bio coal-C_T blend (CRI = 32.1%, CSR= 54.2%) was comparable to that of C_T. Bio coke prepared from carbon neutral biomass-derivates such as bio coal use in steel industry could be a pathway towards green steel production. (author)