Increasing the sustainability of steel production in the electric arc furnace by substituting fossil coal with biochar agglomerates

摘要

Biochar fines from a wood gasification plant and from pyrolysis of agricultural residues were investigated as substitutes for fossil coal used in the steel production in the electric arc furnace (EAF). During previous tests biochar fines with high specific surface showed problematic burn-off behaviour. Therefore the agglomeration behaviour of the biochar fines was investigated. Different binary and ternary mixtures of biochar with water and binders were tested in a hydraulic stamp press and evaluated with regard to green strength and fatigue strength of the briquettes after 3 days. One selected mixture was used to produce pillow briquettes in a double roll press. The abrasion behaviour of the produced briquettes was tested and compared to an anthracite reference coal (RC). Melting tests in a pilot EAF showed that the agglomerated biochar reacts similar to the RC. The briquetting leads to reduced reactivity and slower burn-off compared to the biochar fines.