Cross-upgrading of biomass hydrothermal carbonization and pyrolysis for high quality blast furnace injection fuel production: Physicochemical characteristics and gasification kinetics analysis

The paper proposes a biomass cross-upgrading process that combines hydrothermal carbonization and pyrolysis to produce high-quality blast furnace injection fuel. The results demonstrate significant reductions in the volatile content of biochar, from 45.35% to 16.19%, as well as decreases in alkali metal content, ash content, and specific surface area. The optimal route for biochar production is hydrothermal carbonization-pyrolysis, resulting in biochar (P-HC) with a higher calorific value, C=C structure, and increased graphitization degree. The apparent activation energy (E) of the sample ranges from 199.1 kJ/mol to 324.8 kJ/mol, with P-HC having an E of 277.8 kJ/mol, lower than that of raw biomass, primary biochar, and anthracite. This makes P-HC more suitable for blast furnace injection fuel. Additionally, the paper proposes a path for P-HC injection in blast furnaces and calculates potential environmental benefits. P-HC offers the highest potential for carbon emission reduction, capable of reducing emissions by 96.04 kg/tHM when replacing 40% coal injection.